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  • 1.
    Lundberg, Peter
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radio Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Ekblad, Alf
    Nilsson, Mats
    13C NMR spectroscopy studies of forest soil microbial activity: Glucose uptake and fatty acid biosynthesis2001In: Soil Biology and Biochemistry, ISSN 0038-0717, Vol. 33, no 4-5, 621-632 p.Article in journal (Refereed)
    Abstract [en]

    The intimate association of soil microorganisms with the soil matrix complicates analysis of their metabolism, since thorough separation of intact cells from the matrix is very difficult using standard protocols. Thus, in the study reported here, in situ glucose decomposition and metabolism in humus from a coniferous forest soil was monitored and evaluated using 'solution state' 13C NMR, which can be used in a non-invasive manner. [U-13C] glucose was added at a concentration of 1.73 mmol C g-1 dry organic matter, which is known to allow maximal substrate induced respiration (SIR), and the microbial metabolism of the added C was followed over a period of 28 days. The data showed that ~50% of the added glucose was consumed within three days, coinciding with the appearance of label in CH3, -CH2- and -CH = CH-groups, and in glycerol-carbons, suggesting that olefinic triacylglycerols were being formed, probably located in oil droplets. During days two to three, around 40% of the consumed glucose C was allocated into solid state components, about 40% was respired and about 20% was found as triglycerols. The triacylglycerol signal reached a maximum after 13 days, but subsequently declined by 60%, as the triacylglycerols were apparently consumed, by day 28 of the incubation. Our results indicate there was an initial formation of structural microbial C (solid state carbon) followed by formation of storage lipid C, which subsequently decreased, probably because it was used to provide the organisms with energy when the external energy source (i.e. the glucose) was depleted. The formation of unsaturated triacylglycerols, typical storage metabolites of eucaryotes, suggests that fungi were the most active organisms in the glucose degradation. ⌐ 2001 Elsevier Science Ltd.

  • 2.
    Olafsdottir, Arndis F.
    et al.
    NU Hospital Grp, Sweden; University of Gothenburg, Sweden.
    Attvall, Stig
    Sahlgrens University Hospital, Sweden; University of Gothenburg, Sweden.
    Sandgren, Ulrika
    Sahlgrens University Hospital, Sweden.
    Dahlqvist, Sofia
    NU Hospital Group, Uddevalla, Sweden.
    Pivodic, Aldina
    Statistiska Konsultgruppen, Sweden.
    Skrtic, Stanko
    University of Gothenburg, Sweden; AstraZeneca Rand D, Sweden.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Lind, Marcus
    NU Hospital Grp, Sweden; University of Gothenburg, Sweden.
    A Clinical Trial of the Accuracy and Treatment Experience of the Flash Glucose Monitor FreeStyle Libre in Adults with Type 1 Diabetes2017In: Diabetes Technology & Therapeutics, ISSN 1520-9156, E-ISSN 1557-8593, Vol. 19, no 3, 164-172 p.Article in journal (Refereed)
    Abstract [en]

    Background: In Sweden, FreeStyle Libre a flash glucose monitoring system came onto the market in 2014 as a complement to self-monitoring of blood glucose. The aim of this study was to evaluate the accuracy and treatment experience of the FreeStyle Libre system. Methods: Fifty-eight adults with type 1 diabetes used FreeStyle Libre for 10-14 days and measured capillary blood glucose levels with the HemoCue blood glucose measurement system at least six times a day simultaneously. Results: For the entire study period, the mean absolute relative difference (MARD) was 13.2% (95% confidence interval [CI] 12.0%-14.4%). MARD was 13.6% (95% CI 12.1%-15.4%) during week 1 and 12.7% (95% CI 11.5%-13.9%) during week 2. The mean absolute difference (MAD) for the whole study period was 19.8mg/dL (1.1mmol/L) (95% CI 17.8-21.8 mg/dL), including 20.5 mg/dL (1.14 mmol/L) during week 1 and 19.0 mg/dL (1.05 mmol/L) during week 2. The overall correlation coefficient was 0.96. For glucose values amp;lt; 72, 72-180, and amp;gt; 180mg/dL (amp;lt; 4, 4-10, and amp;gt; 10 mmol/L), the MARD was 20.3% (95% CI 17.7%-23.1%), 14.7% (95% CI 13.4%-16%), and 9.6% (95% CI 8.5%-10.8%), respectively, and respective MAD values were 12.3, 17.8, and 23.6 mg/dL (0.69, 0.99, and 1.31mmol/L). Using the 10-item visual analog scale, patients rated their experience with FreeStyle Libre as generally positive, with mean values ranging from 8.22 to 9.8. Conclusions: FreeStyle Libre had a similar overall MARD as continuous blood glucose monitoring systems in earlier studies when studied in similar at-home conditions. The overall patient satisfaction was high.

  • 3.
    Petersson, Ulla
    et al.
    Linköping University, Department of Medical and Health Sciences, General Practice. Linköping University, Faculty of Health Sciences.
    Östgren, Carl Johan
    Linköping University, Department of Medical and Health Sciences, General Practice. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Primary Health Care in Motala.
    Brudin, Lars
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Nilsson, Peter
    Department of Clinical Sciences, Lund University, University Hospital, Malmö , Sweden.
    A consultation-based method is equal to SCORE and an extensive laboratory-based method in predicting risk of future cardiovascular disease2009In: European Journal of Cardiovascular Prevention & Rehabilitation, ISSN 1741-8267, E-ISSN 1741-8275, Vol. 16, no 5, 536-540 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: As cardiovascular disease (CVD) is one of the most common causes of mortality worldwide, much interest has been focused on reliable methods to predict cardiovascular risk.

    DESIGN: A cross-sectional, population-based screening study with 17-year follow-up in Southern Sweden.

    METHODS: We compared a non-laboratory, consultation-based risk assessment method comprising age, sex, present smoking, prevalent diabetes or hypertension at baseline, blood pressure (systolic >/=140 or diastolic >/=90), waist/height ratio and family history of CVD to Systemic COronary Risk Evaluation (SCORE) and a third model including several laboratory analyses, respectively, in predicting CVD risk. The study included clinical baseline data on 689 participants aged 40-59 years without CVD. Blood samples were analyzed for blood glucose, serum lipids, insulin, insulin-like growth factor-I, insulin-like growth factor binding protein-1, C-reactive protein, asymmetric dimethyl arginine and symmetric dimethyl arginine. During 17 years, the incidence of total CVD (first event) and death was registered.

    RESULTS: A non-laboratory-based risk assessment model, including variables easily obtained during one consultation visit to a general practitioner, predicted cardiovascular events as accurately [hazard ratio (HR): 2.72; 95% confidence interval (CI): 2.18-3.39, P<0.001] as the established SCORE algorithm (HR: 2.73; 95% CI: 2.10-3.55, P<0.001), which requires laboratory testing. Furthermore, adding a combination of sophisticated laboratory measurements covering lipids, inflammation and endothelial dysfunction, did not confer any additional value to the prediction of CVD risk (HR: 2.72; 95% CI: 2.19-3.37, P<0.001). The c-statistics for the consultation model (0.794; 95% CI: 0.762-0.823) was not significantly different from SCORE (0.767; 95% CI: 0.733-0.798, P=0.12) or the extended model (0.806; 95% CI: 0.774-0.835, P=0.55).

    CONCLUSION: A risk algorithm based on non-laboratory data from a single primary care consultation predicted long-term cardiovascular risk as accurately as either SCORE or an elaborate laboratory-based method in a defined middle-aged population.

  • 4.
    Ekman, Bertil
    et al.
    Linköping University, Department of Medicine and Care, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Lindström, Torbjörn
    Linköping University, Department of Medicine and Care, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Nyström, Fredrik
    Linköping University, Department of Medicine and Care, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Olsson, Anders
    Linköping University, Department of Medicine and Care, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Toss, Göran
    Linköping University, Department of Medicine and Care, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Arnqvist, Hans
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    A dose titration model for recombinant GH substitution aiming at normal plasma concentrations of IGF-I in hypopituitary adults2002In: European Journal of Endocrinology, ISSN 0804-4643, E-ISSN 1479-683X, Vol. 147, no 1, 49-57 p.Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To evaluate a dose titration model for recombinant human GH substitution in adult patients with GH deficiency, aiming at normal plasma levels of IGF-I.

    DESIGN AND METHODS: Eighteen patients participated and a start dose of 0.17 mg GH/day was used except by two men who started with 0.33 mg/day. To demonstrate a clear GH effect the patients were first titrated, with steps of 0.17 mg GH/day every 6-8 weeks, to IGF-I levels in the upper range of age-adjusted reference values. The GH dose was then reduced 1 dose step and kept for a further 6 months. For comparison we investigated 17 healthy control subjects.

    RESULTS: Plasma IGF-I was increased after 2 weeks on the start dose and did not increase further for up to 8 weeks. Women had significantly lower GH sensitivity than men measured as net increment of IGF-I on the start dose of GH. GH sensitivity was not changed by age. The plasma IGF-I levels increased from 76.3+/-47.0 (s.d.) to 237+/-97 microg/l at the end of the study (P<0.001), and similar IGF-I levels were obtained in both sexes. The maintenance median GH dose was 0.33 mg/day in males and 0.83 mg/day in females (P=0.017). The GH dose correlated negatively with age in both sexes. Body weight, very low density triglycerides, lipoprotein(a) (Lp(a)), and fasting insulin increased, whereas insulin sensitivity index (QUICKI) decreased significantly. In comparison with the controls, the patients had lower fasting blood glucose, fasting insulin and Lp(a) levels at baseline, but these differences disappeared after GH substitution. The two groups had equal insulin sensitivity (QUICKI), but 2 h oral glucose tolerance test values of blood glucose and insulin were significantly higher in the patients at the end of the study.

    CONCLUSIONS: In conclusion our data suggest that the starting dose of GH substitution and the dose titration steps should be individualised according to GH sensitivity (gender) and the IGF-I level aimed for (age). The reduced insulin sensitivity induced by GH substitution could be viewed as a normalisation if compared with control subjects.

  • 5.
    Usman Ali, Syed M
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Danielsson, B.
    Lund University.
    A fast and sensitive potentiometric glucose microsensor based on glucose oxidase coated ZnO nanowires grown on a thin silver wire2010In: Sensors and actuators. B, Chemical, ISSN 0925-4005, Vol. 145, no 2, 869-874 p.Article in journal (Refereed)
    Abstract [en]

    In this study, a potentiometric glucose biosensor was fabricated by immobilization of glucose oxidase on to zinc oxide nanowires. Zinc oxide nanowires with 250-300 nm diameters and approximately 1.2 mu m lengths were grown on the surface of silver wires with a diameter of 250 mu m. Glucose oxidase (GOD) was electrostatically immobilized on the surface of the well aligned zinc oxide nanowires resulting in sensitive, selective, stable and reproducible glucose biosensors. The potentiometric response vs. Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (0.5-1000 mu M) suitable for intracellular glucose detection. By applying a membrane on the sensor the linear range could be extended to 0.5 mu M to 10 mM, which increased the response time from less than 1 to 4s. On the other hand the membrane increased the sensor durability considerably. The sensor response was unaffected by normal concentrations of common interferents with glucose sensing such as uric acid and ascorbic acid.

  • 6.
    Turner, Anthony
    et al.
    Cranfield University, UK.
    and seven more authors,
    A ferrocene-based enzyme electrode for amperometric glucose detection1983In: Bioelectrochemistry and Bioenergetics, University of Nottingham , 1983Conference paper (Refereed)
  • 7.
    Olsson, John
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Winquist, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    A Flow System for Urea and Glucose Measurement with a Self Polishing Electronic TongueManuscript (preprint) (Other academic)
    Abstract [en]

    A self polishing voltammetric electronic tongue was evaluated for simultaneousl prediction of urea and glucose concentrations in phosphate buffer in a flow system. The voltammetric electronic tongue consisted of three working electrodes (gold, platinum and rhodium) and a counter electrode, also acting as reference electrode. The flowsystem contained five valves, controlled by a computer and a peristaltic pump. Two batches of sample standards were used; one for calibration and the other for validation. The system could predict concentrations of urea and glucose in the interval 0 – 20 mM in the validation batch. No significant difference between the two batches was seen. The self polishing approach makes the system in principle maintenance free. With a large potential use in hemodialysis.

  • 8.
    HENDRY, SP
    et al.
    ; .
    TURNER, APF
    Cranfield University, UK.
    A GLUCOSE SENSOR UTILIZING TETRACYANOQUINODIMETHANE AS A MEDIATOR1988In: Hormone and Metabolic Research, ISSN 0018-5043, Vol. 20, 37-40 p.Article in journal (Refereed)
    Abstract [en]

    n/a

  • 9.
    Nyman, Elin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Brännmark, Cecilia
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Palmér, Robert
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Brugård, Jan
    MathCore Engn.
    Nyström, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Cedersund, Gunnar
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    A Hierarchical Whole-body Modeling Approach Elucidates the Link between in Vitro Insulin Signaling and in Vivo Glucose Homeostasis2011In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 286, no 29, 26028-26041 p.Article in journal (Refereed)
    Abstract [en]

    Type 2 diabetes is a metabolic disease that profoundly affects energy homeostasis. The disease involves failure at several levels and subsystems and is characterized by insulin resistance in target cells and tissues (i.e. by impaired intracellular insulin signaling). We have previously used an iterative experimental-theoretical approach to unravel the early insulin signaling events in primary human adipocytes. That study, like most insulin signaling studies, is based on in vitro experimental examination of cells, and the in vivo relevance of such studies for human beings has not been systematically examined. Herein, we develop a hierarchical model of the adipose tissue, which links intracellular insulin control of glucose transport in human primary adipocytes with whole-body glucose homeostasis. An iterative approach between experiments and minimal modeling allowed us to conclude that it is not possible to scale up the experimentally determined glucose uptake by the isolated adipocytes to match the glucose uptake profile of the adipose tissue in vivo. However, a model that additionally includes insulin effects on blood flow in the adipose tissue and GLUT4 translocation due to cell handling can explain all data, but neither of these additions is sufficient independently. We also extend the minimal model to include hierarchical dynamic links to more detailed models (both to our own models and to those by others), which act as submodules that can be turned on or off. The resulting multilevel hierarchical model can merge detailed results on different subsystems into a coherent understanding of whole-body glucose homeostasis. This hierarchical modeling can potentially create bridges between other experimental model systems and the in vivo human situation and offers a framework for systematic evaluation of the physiological relevance of in vitro obtained molecular/cellular experimental data.

  • 10.
    Ali Kamyabi, Mohammad
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Hajari, Nasim
    University of Zanjan, Iran .
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    A high-performance glucose biosensor using covalently immobilised glucose oxidase on a poly(2,6-diaminopyridine)/carbon nanotube electrode2013In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 116, 801-808 p.Article in journal (Refereed)
    Abstract [en]

    A highly-sensitive glucose biosensor amenable to ultra-miniaturisation was fabricated by immobilisation of glucose oxidase (GOx), onto a poly(2,6-diaminopyridine)/multi-walled carbon nanotube/glassy carbon electrode (poly(2,6-DP)/MWNT/GCE). Cyclic voltammetry was used for both the electrochemical synthesis of poly-(2,6-DP) on the surface of a MWNT-modified GC electrode, and characterisation of the polymers deposited on the GC electrode. The synergistic effect of the high active surface area of both the conducting polymer, i.e., poly-(2,6-DP) and MWNT gave rise to a remarkable improvement in the electrocatalytic properties of the biosensor. The transfer coefficient (alpha), heterogeneous electron transfer rate constant and Michaelis-Menten constant were calculated to be 0.6, 4 s(-1) and 0.20 mM at pH 7.4, respectively. The GOx/poly(2,6-DP)/MWNT/GC bioelectrode exhibited two linear responses to glucose in the concentration ranging from 0.42 mu M to 8.0 mM with a correlation coefficient of 0.95, sensitivity of 52.0 mu AmM-1 cm(-2), repeatability of 1.6% and long-term stability, which could make it a promising bioelectrode for precise detection of glucose in the biological samples. (C) 2013 Elsevier B.V. All rights reserved.

  • 11.
    Folkesson, Tchou
    et al.
    Pharmaceutical Biosciences, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden,.
    Samuelsson, Anders
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Intensive Care UHL. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Dahlström, B.
    Berzelius Clinical Research Center, Linköping, Sweden.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Plastic Surgery, Hand surgery UHL. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    A human vascular model based on microdialysis for the assessment of the vasoconstrictive dose-response effects of noradrenaline and vasopressin in skin: in JOURNAL OF VASCULAR RESEARCH, vol 48, pp 320-3202011In: JOURNAL OF VASCULAR RESEARCH, Karger , 2011, 320-320 p.Conference paper (Refereed)
    Abstract [en]

    Microdialysis is a well-established technique for continuous sampling of small, water-soluble molecules within the extracellular fluid space in vivo. It also allows the use of microdoses of drugs, and the simultaneous evaluation of their related effects at the site of action. The present study was an experimental, randomized microdose trial to develop a human vascular model of dose response. We aimed to evaluate a microdialysis dosing method using urea clearance as a marker of druginduced changes in dermal blood flow and metabolism (glucose and lactate) in 12 healthy volunteers. We found that asymptomatic vasoconstriction can be detected by continuous microdialysis measurements of urea clearance in dermal tissue. More importantly, dose-effect relations using the Emax model could be constructed using the corresponding data on drug doses and both the urea clearance-based flow estimates and the changes in concentrations of tissue metabolites. This in vivo human experimental skin model offers an interesting tool with which both the dose-response effects on blood flow and concentrations of tissue metabolites of potent vasoactive substances can be evaluated.

  • 12.
    Tchou Folkesson, Kim
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Samuelsson, Anders
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Intensive Care UHL.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences.
    Dahlström, Bengt
    AB Biopharmacon, Uppsala.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Plastic Surgery, Hand surgery UHL. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    A Human Vascular Model Based on Microdialysis for the Assessment of the Vasoconstrictive Dose-Response Effects of Norepinephrine and Vasopressin in Skin2012In: Microcirculation, ISSN 1073-9688, Vol. 19, no 4, 352-359 p.Article in journal (Refereed)
    Abstract [en]

    Abstract Objective: Microdialysis enables drug delivery in the skin and simultaneous measurement of their effects. The present study aimed to evaluate dose-dependent changes in blood flow and metabolism during microdialysis of norepinephrine and vasopressin. Methods: We investigated whether increasing concentrations of norepinephrine (NE, 1.859 mu mol/L) and vasopressin (VP, 1100 nmol/L), delivered sequentially in one catheter or simultaneously through four catheters, yield dose-dependent changes in blood flow (as measured using urea clearance) and metabolism (glucose and lactate). Results: We found a significant dose-dependent vasoconstriction with both drugs. Responses were characterized by a sigmoid dose response model. Urea in the dialysate increased from a baseline of 7.9 +/- 1.7 to 10.9 +/- 0.9 mmol/L for the highest concentration of NE (p andlt; 0.001) and from 8.1 +/- 1.4 to 10.0 +/- 1.7 mmol/L for the highest concentration of VP (p = 0.037). Glucose decreased from 2.3 +/- 0.7 to 0.41 +/- 0.18 mmol/L for NE (p = 0.001) and from 2.7 +/- 0.6 to 1.3 +/- 0.5 mmol/L for VP (p andlt; 0.001). Lactate increased from 1.1 +/- 0.4 to 2.6 +/- 0.5 mmol/L for NE (p = 0.005) and from 1.1 +/- 0.4 to 2.6 +/- 0.5 mmol/L for VP (p = 0.008). There were no significant differences between responses from a single catheter and from those obtained simultaneously using multiple catheters. Conclusions: Microdialysis in the skin, either with a single catheter or using multiple catheters, offers a useful tool for studying dose response effects of vasoactive drugs on local blood flow and metabolism without inducing any systemic effects.

  • 13.
    Svedjeholm, Rolf
    et al.
    Linköping University, Department of Medicine and Health Sciences, Thoracic Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Vidlund, Marten
    Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery. Linköping University, Faculty of Health Sciences.
    Vanhanen, Ingemar
    Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery. Linköping University, Faculty of Health Sciences.
    Hakanson, Erik
    Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery. Linköping University, Faculty of Health Sciences.
    A metabolic protective strategy could improve long-term survival in patients with LV-dysfunction undergoing CABG2010In: SCANDINAVIAN CARDIOVASCULAR JOURNAL, ISSN 1401-7431, Vol. 44, no 1, 45-58 p.Article in journal (Refereed)
    Abstract [en]

    Objective. Adverse outcome after CABG is closely related to postoperative heart failure precipitated by ischemia and myocardial infarction. Restrictive use of inotropes is therefore desirable. Patients with preoperative left ventricular dysfunction are a high-risk group in this respect. To reduce myocardial oxygen expenditure we evolved a metabolic strategy for perioperative care. Design. Observational study on 104 consecutive patients with severe left ventricular dysfunction undergoing CABG. The metabolic strategy implied physiological measures to minimize myocardial oxygen expenditure including restrictive use of inotropes and specific measures such as extended CPB and metabolic support to facilitate myocardial recovery. Hemodynamic state was primarily assessed by mixed venous oxygen saturation (SvO(2)). Follow-up averaged 9.7 +/- 1.4 years. Results. LVEF was 0.30 +/- 0.05 (range 0.20-0.37) and 3.5 +/- 1.3 vessels were bypassed. Inotropes were used in 6.7% for weaning from CPB. Increase of s-creatinine by andgt;= 50% compared to preoperative values was observed in 2.9%. Logistic EuroSCORE was 8.3% whereas observed 30-day mortality was 1.0%. Crude 5-year survival was 89.4%. Conclusions. The metabolic strategy allowed restrictive use of inotropes and was associated with encouraging long-term survival. Renal function was well preserved suggesting that SvO(2) served as an adequate marker of circulation. Randomized trials with metabolic support are warranted.

  • 14.
    Sunnaker, Mikael
    et al.
    Fraunhofer Chalmers Research Centre for Industrial Math.
    Cedersund, Gunnar
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Jirstrand, Mats
    Fraunhofer Chalmers Research Centre for Industrial Math.
    A method for zooming of nonlinear models of biochemical systems2011In: BMC Systems Biology, ISSN 1752-0509, Vol. 5, no 140Article in journal (Refereed)
    Abstract [en]

    Background: Models of biochemical systems are typically complex, which may complicate the discovery of cardinal biochemical principles. It is therefore important to single out the parts of a model that are essential for the function of the system, so that the remaining non-essential parts can be eliminated. However, each component of a mechanistic model has a clear biochemical interpretation, and it is desirable to conserve as much of this interpretability as possible in the reduction process. Furthermore, it is of great advantage if we can translate predictions from the reduced model to the original model. less thanbrgreater than less thanbrgreater thanResults: In this paper we present a novel method for model reduction that generates reduced models with a clear biochemical interpretation. Unlike conventional methods for model reduction our method enables the mapping of predictions by the reduced model to the corresponding detailed predictions by the original model. The method is based on proper lumping of state variables interacting on short time scales and on the computation of fraction parameters, which serve as the link between the reduced model and the original model. We illustrate the advantages of the proposed method by applying it to two biochemical models. The first model is of modest size and is commonly occurring as a part of larger models. The second model describes glucose transport across the cell membrane in bakers yeast. Both models can be significantly reduced with the proposed method, at the same time as the interpretability is conserved. less thanbrgreater than less thanbrgreater thanConclusions: We introduce a novel method for reduction of biochemical models that is compatible with the concept of zooming. Zooming allows the modeler to work on different levels of model granularity, and enables a direct interpretation of how modifications to the model on one level affect the model on other levels in the hierarchy. The method extends the applicability of the method that was previously developed for zooming of linear biochemical models to nonlinear models.

  • 15.
    Hillman, Jan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Neurosurgery. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Aneman, Oscar
    Anderson, Chris
    Sjögren, Florence
    Säberg, Carina
    Mellergård, Per Erik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Neurosurgery. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    A microdialysis technique for routine measurement of macromolecules in the injured human brain2005In: Neurosurgery, ISSN 0148-396X, Vol. 56, no 6, 1264-1268 p.Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To evaluate a new intracerebral microdialysis catheter with a high-cutoff membrane and its potential for the study of macromolecules in the human brain. METHODS: Paired intracerebral microdialysis catheters were inserted in 10 patients who became comatose after subarachnoid hemorrhage or traumatic brain injury and were then treated in our neurosurgical unit. The only differences from the routine use of microdialysis in our clinic were the length (20 mm) and cutoff properties of the catheter membranes (100 kD) and the perfusion fluids used (standard perfusion fluid, 3.5% albumin, or Ringer-dextran 60). Samples were weighed (for net fluid fluxes) and analyzed at bedside (for routine metabolites) and later in the laboratory (for total protein and interleukin-6). The in vitro recovery of glucose, glutamate, and glycerol were also investigated under different conditions. RESULTS: Even brief perfusion with standard perfusion fluid resulted in a significant loss of volume from the microdialysis system. For albumin and Ringer-dextran 60 fluid, recovery was comparable to standard settings. Interleukin-6 (highest value close to 25,000 pg/ml) was sampled from all catheters, and total protein was analyzed from catheters perfused with Ringer-dextran 60 (average concentration, 234 μg protein/ml). There were detectable patterns of variations in the concentration of interleukin-6, seemingly related to concomitant variations in intracerebral conditions. In the present study, no direct comparison was made with the standard CMA 70 catheter (CMA Microdialysis, Stockholm, Sweden), but in vivo, the measured mean concentrations of glucose, glycerol, lactate, and pyruvate were comparable to those previously reported from standard catheters. In vitro, the recovery of metabolites was better when using Ringer-dextran 60 compared with albumin. CONCLUSION: Microdialysis catheters with high-cutoff membranes can be used in routine clinical practice, allowing for sampling and analysis of cytokines and other macromolecules.

  • 16.
    ul Hasan, Kamran
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. CESAT, Islamabad, Pakistan.
    Asif, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. COMSATS Institute Informat Technology, Lahore, Pakistan.
    Umair Hassan, Muhammad
    COMSATS Institute Informat Technology, Lahore, Pakistan.
    Sandberg, Mats O.
    Acreo AB, Norrköping, Sweden.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Fagerholm, Siri
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    A Miniature Graphene-based Biosensor for Intracellular Glucose Measurements2015In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 0019-4686, Vol. 174, 574-580 p.Article in journal (Refereed)
    Abstract [en]

    We report on a small and simple graphene-based potentiometric sensor for the measurement of intracellular glucose concentration. A fine borosilicate glass capillary coated with graphene and subsequently immobilized with glucose oxidase (GOD) enzyme is inserted into the intracellular environment of a single human cell. The functional groups on the edge plane of graphene assist the attachment with the free amine terminals of GOD enzyme, resulting in a better immobilization. The sensor exhibits a glucose-dependent electrochemical potential against an Ag/AgCl reference microelectrode which is linear across the whole concentration range of interest (10 - 1000 mu M). Glucose concentration in human fat cell measured by our graphene-based sensor is in good agreement with nuclear magnetic resonance (NMR) spectroscopy.

  • 17.
    Stenkula, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    A molecular approach to insulin signalling and caveolae in primary adipocytes2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The prevalence of type II diabetes is increasing at an alarming rate due to the western world lifestyle. Type II diabetes is characterized by an insulin resistance distinguished by impaired glucose uptake in adipose and muscle tissues. The molecular mechanisms behind the insulin recistance and also the knowledge considering normal insulin signalling in fat cells, especially in humans, are still unclear.

    Insulin receptor substrate (IRS) is known to be important for medating the insulin-induced signal from the insulin receptor into the cell. We developed and optimized a method for transfection of primary human adipocytes by electroporation. By recombinant expression of proteins, we found a proper IRS to be crucial for both mitogenic and metabolic signalling in human adipocytes. In human, but not rat, primary adipocytes we found IRS1 to be located at the plasma membrane in non-insulin stimulated cells. Insulin stimulation resulted in a two-fold increase of the amount of IRS1 at the plasma membrane in human cells, compared with a 12-fold increase in rat cells. By recombinant expression of IRS1 we found the species difference between human and rat IRS1 to depend on the IRS proteins and not on properties of the host cell.

    The adipocytes function as an energy store, critical for maintaining the energy balance, and obesity strongly correlates with insulin resistance. The insulin sensitivity of the adipocytes with regard to the size of the cells was examined by separating small and large cells from the same subject. We found no increase of the GLUT4 translocation to the plasma membrane following insulin stimulation in the large cells, whereas there was a two-fold increase in the small cells. This finding supports the idea of a causal relationship between the enlarged fat cells and reduced insulin sensitivity found in obese subjects.

    The insulin receptor is located and functional in a specific membrane structure, the caveola. The morphology of the caveola and the localization of the caveolar marker proteins caveolin-1 and -2 were examined. Caveolae were shown to be connected to the exterior by a narrow neck. Caveolin was found to be located at the neck region of caveolae, which imply importance of caveolin for maintaining and sequestering caveolae to the plasma membrane.

    In conclusion, the transfection technique proved to be highly useful for molecular biological studies of insulin signal transduction and morphology in primary adipocytes.

    List of papers
    1. Expression of a mutant IRS inhibits metabolic and mitogenic signalling of insulin in human adipocytes
    Open this publication in new window or tab >>Expression of a mutant IRS inhibits metabolic and mitogenic signalling of insulin in human adipocytes
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    2004 (English)In: Molecular and Cellular Endocrinology, ISSN 0303-7207, Vol. 221, no 1-2, 1-8 p.Article in journal (Refereed) Published
    Abstract [en]

    Adipose tissue is a primary target of insulin, but knowledge about insulin signalling in human adipocytes is limited. We developed an electroporation technique for transfection of primary human adipocytes with a transfection efficiency of 15% ± 5 (mean ± S.D.). Human adipocytes were co-transfected with a mutant of IRS-3 (all four potential PI3-kinase binding motifs mutated: IRS-3F4) and HA-tagged protein kinase B (HA-PKB/Akt). HA-PKB/Akt was immunoprecipitated from cell lysates with anti-HA antibodies, resolved with SDS-PAGE, and immunoblotted with phospho-specific antibodies. We found that IRS-3F4 blocked insulin stimulation of HA-PKB/Akt phosphorylation and in further analyses also translocation of recombinant HA-tagged glucose transporter to the plasma membrane. IRS-3F4 also blocked insulin-induced activation of the transcription factor Elk-1. Our results demonstrate the critical importance of IRS for metabolic as well as mitogenic signalling by insulin. This method for transfection of primary human adipocytes will be useful for studying insulin signalling in human adipocytes with molecular biological techniques.

    Keyword
    Insulin, Transfection, Human, Adipocytes, Protein kinase B, Elk-1
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14538 (URN)10.1016/j.mce.2004.04.011 (DOI)000222854100001 ()
    Available from: 2007-06-01 Created: 2007-06-01 Last updated: 2013-10-22Bibliographically approved
    2. Cell surface orifices of caveolae and localization of caveolin to the necks of caveolae in adipocytes
    Open this publication in new window or tab >>Cell surface orifices of caveolae and localization of caveolin to the necks of caveolae in adipocytes
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    2003 (English)In: Molecular Biology of the Cell, ISSN 1059-1524, E-ISSN 1939-4586, Vol. 14, no 10, 3967-3976 p.Article in journal (Refereed) Published
    Abstract [en]

    Caveolae are noncoated invaginations of the plasma membrane that form in the presence of the protein caveolin. Caveolae are found in most cells, but are especially abundant in adipocytes. By high-resolution electron microscopy of plasma membrane sheets the detailed structure of individual caveolae of primary rat adipocytes was examined. Caveolin-1 and -2 binding was restricted to the membrane proximal region, such as the ducts or necks attaching the caveolar bulb to the membrane. This was confirmed by transfection with myc-tagged caveolin-1 and -2. Essentially the same results were obtained with human fibroblasts. Hence caveolin does not form the caveolar bulb in these cells, but rather the neck and may thus act to retain the caveolar constituents, indicating how caveolin participates in the formation of caveolae. Caveolae, randomly distributed over the plasma membrane, were very heterogeneous, varying in size between 25 and 150 nm. There was about one million caveolae in an adipocyte, which increased the surface area of the plasma membrane by 50%. Half of the caveolae, those larger than 50 nm, had access to the outside of the cell via ducts and 20-nm orifices at the cell surface. The rest of the caveolae, those smaller than 50 nm, were not open to the cell exterior. Cholesterol depletion destroyed both caveolae and the cell surface orifices.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14539 (URN)10.1091/mbc.E03-01-0050 (DOI)
    Available from: 2007-06-01 Created: 2007-06-01 Last updated: 2013-09-10
    3. Human, but not rat, IRS1 targets to the plasma membrane in both human and rat primary adipocytes
    Open this publication in new window or tab >>Human, but not rat, IRS1 targets to the plasma membrane in both human and rat primary adipocytes
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    2007 (English)In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, Vol. 363, no 3, 840-845 p.Article in journal (Refereed) Published
    Abstract [en]

    Adipocytes are primary targets for insulin control of metabolism. The activated insulin receptor phosphorylates insulin receptor substrate-1 (IRS1), which acts as a docking protein for downstream signal mediators. In the absence of insulin stimulation, IRS1 in rat adipocytes is intracellular but in human adipocytes IRS1 is constitutively targeted to the plasma membrane. Stimulation of adipocytes with insulin increased the amount of IRS1 at the plasma membrane 2-fold in human adipocytes, but >10-fold in rat adipocytes, with the same final amount of IRS1 at the plasma membrane in cells from both species. Cross-transfection of rat adipocytes with human IRS1, or human adipocytes with rat IRS1, demonstrated that the species difference was due to the IRS1 protein and not the cellular milieus or posttranslational modifications. Chimeric IRS1, consisting of the conserved N-terminus of rat IRS1 with the variable C-terminal of human IRS1, did not target the plasma membrane, indicating that subtle sequence differences direct human IRS1 to the plasma membrane.

    Keyword
    Insulin receptor substrate; Human; Rat; Insulin; Plasma membrane; Signaling; Transfection; Caveolae
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14540 (URN)10.1016/j.bbrc.2007.09.065 (DOI)
    Available from: 2007-06-01 Created: 2007-06-01 Last updated: 2013-09-10
    4. Insulin-induced GLUT4 translocation to the plasma membrane is blunted in large compared with small primary fat cells isolated from the same individual
    Open this publication in new window or tab >>Insulin-induced GLUT4 translocation to the plasma membrane is blunted in large compared with small primary fat cells isolated from the same individual
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    2007 (English)In: Diabetologia, ISSN 0012-186X, Vol. 50, no 8, 1716-1722 p.Article in journal (Refereed) Published
    Abstract [en]

    Aims/hypothesis: Several studies have suggested that large fat cells are less responsive to insulin than small fat cells. However, in these studies, large fat cells from obese individuals were compared with smaller fat cells from leaner participants, in effect making it impossible to draw conclusions about whether there is a causal relationship between fat cell size and insulin sensitivity. We hypothesised that small fat cells might be more insulin-responsive than large adipocytes when obtained from the same individual.

    Materials and methods: We developed a method of sorting isolated primary human fat cells by using nylon filters of two different pore sizes. The cells were stained to visualise DNA, which allowed discrimination from artefacts such as lipid droplets. The sorted cells were left to recover overnight, since we had previously demonstrated that this is necessary for correct assessment of insulin response.

    Results: We found similar amounts of the insulin receptor (IR), IRS-1 and GLUT4 when we compared small and large adipocytes from the same volunteer by immunoblotting experiments using the same total cell volume from both cell populations. Activation of IR, IRS-1 and Akt1 (also known as protein kinase B) by insulin was similar in the two cell populations. However, immunofluorescence confocal microscopy of plasma membrane sheets did not reveal any increase in the amount of GLUT4 in the plasma membrane following insulin stimulation in the large fat cells, whereas we saw a twofold increase in the amount of GLUT4 in the small fat cells.

    Conclusions/interpretation: Our results support a causal relationship between the accumulation of large fat cells in obese individuals and reduced insulin responsiveness.

    Keyword
    Adipocyte, GLUT4, Human, Insulin, Insulin receptor, Insulin resistance, IRS-1, Primary fat cell
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14541 (URN)10.1007/s00125-007-0713-1 (DOI)
    Available from: 2007-06-01 Created: 2007-06-01 Last updated: 2013-09-10Bibliographically approved
  • 18.
    Turner, Anthony
    Cranfield University, UK.
    A new approach to blood glucose tests1983In: Balance, Vol. 76, 4-5 p.Article in journal (Refereed)
  • 19.
    Psoma, Sotiria D.
    et al.
    Cranfield University, Cranfield Health, Cranfield, Bedfordshire, UK.
    D. van der Wal, Peter
    EPFL, IMT-SAMLAB, Switzerland.
    Frey, Olivier
    EPFL, IMT-SAMLAB, Switzerland.
    de Rooij, Nicolaas F.
    EPFL, IMT-SAMLAB, Switzerland.
    Turner, Anthony P. F.
    Cranfield University, UK.
    A novel enzyme entrapment in SU-8 microfabricated films for glucose micro-biosensors2010In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 26, no 4, 1582-1587 p.Article in journal (Refereed)
    Abstract [en]

    The present work investigates the utilisation of the widely used SU-8 photoresist as an immobilisation matrix for glucose oxidase (GOx) for the development of glucose micro-biosensors. The strong advantage of the proposed approach is the simultaneous enzyme entrapment during the microfabrication process within a single step, which is of high importance for the simplification of the BioMEMS procedures. Successful encapsulation of the enzyme GOx in "customised" SU-8 microfabricated structures was achieved through optimisation of the one-step microfabrication process. Although the process involved contact with organic solvents, UV-light exposure, heating for pre- and post-bake and enzyme entrapment in a hard and rigid epoxy resin matrix, the enzyme retained its activity after encapsulation in SU-8. Measurements of the immobilised enzymes activity inside the SU-8 matrix were carried out using amperometric detection of hydrogen peroxide in a 3-electrode setup. Films without enzyme showed negligible variation in current upon the addition of glucose, as opposed to films with encapsulated enzyme which showed a very clear increase in current. Experiments using films of increased thickness or enzyme concentration, showed a higher response, thus proving that the enzyme remained active not only on the films surface, but also inside the matrix as well. The proposed enzyme immobilisation in SU-8 films opens up new possibilities for combining BioMEMS with biosensors and organic electronics.

  • 20.
    Turner, Anthony
    et al.
    Cranfield University, UK.
    and five more authors,
    A novel enzyme immobilisation technique using a one-step microfabrication process for disposable glucose micro-biosensor applications2010Conference paper (Refereed)
  • 21.
    Turner, Anthony
    et al.
    Cranfield University, UK.
    and eight more authors,
    A novel enzyme-based glucose sensor: construction and clinical potential1983In: Abstracts of the Medical and Scientific Section Autumn Meeting, 1983Conference paper (Refereed)
  • 22.
    Lundberg, Peter
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
    Vogel, Hans J.
    Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
    Brodelius, Peter E.
    Department of Plant Biochemistry, Lund University, Lund, Sweden.
    A phosphorus-31 nuclear magnetic resonance study of elicitor-mediated metabolic changes in Catharanthus roseus suspension cultures1997In: In vitro cellular & developmental biology. Plant, ISSN 1054-5476, E-ISSN 1475-2689, Vol. 33, no 4, 301-305 p.Article in journal (Refereed)
    Abstract [en]

    The induction of metabolic changes in suspension cultured cells of Catharanthus roseus upon elicitation has been investigated. Addition of a yeast glucan preparation to the growth medium resulted in induction of phenylalanine ammonia lyase. Phosphate uptake and metabolism of elicited cells was followed by 31P nuclear magnetic resonance. The uptake rate of Pi from the medium by oxygenated cells of C. roseus was reduced immediately after elicitation. Despite this reduced Pi uptake elicited cells had significantly increased amounts of ATP (twofold increase within 6 h). Cytoplasmic levels of Pi, phosphomonoesters, and Uridine Diphasphate glucose (UDP-Glc) were unaffected by eliciation. Furthermore, the cytoplasmic and vacuolar pH remained constant after addition of elicitor.

  • 23.
    Usman Ali, Syed
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. NED University of Engineering and Technology, Pakistan.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Kashif, Muhammad
    University of Malaysia Perlis, Malaysia.
    Hashim, Uda
    University of Malaysia Perlis, Malaysia.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    A Potentiometric Indirect Uric Acid Sensor Based on ZnO Nanoflakes and Immobilized Uricase2012In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 12, no 3, 2787-2797 p.Article in journal (Refereed)
    Abstract [en]

    In the present work zinc oxide nanoflakes (ZnO-NF) structures with a wall thickness around 50 to 100 nm were synthesized on a gold coated glass substrate using a low temperature hydrothermal method. The enzyme uricase was electrostatically immobilized in conjunction with Nafion membrane on the surface of well oriented ZnO-NFs, resulting in a sensitive, selective, stable and reproducible uric acid sensor. The electrochemical response of the ZnO-NF-based sensor vs. a Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (500 nM to 1.5 mM). In addition, the ZnO-NF structures demonstrate vast surface area that allow high enzyme loading which results provided a higher sensitivity. The proposed ZnO-NF array-based sensor exhibited a high sensitivity of similar to 66 mV/ decade in test electrolyte solutions of uric acid, with fast response time. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea.

  • 24.
    Hedborg, Julia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    A Printed Biosensor Based on an Organic Electrochemical Transistor with Mediated Gate Electrode2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biosensor technology is an expanding field of research and there is a great market demand for low-cost disposable sensors. The aim of this project was to come up with a printed, disposable biosensor for glucose based on an organic electrochemical transistor (OECT). The organic semiconductor PEDOT:PSS was used as the material for the transistor channel and the gate electrode was made of carbon bulk modified with the different redox mediators potassium ferricyanide and ferrocene and the catalyst cobalt phthalo cyanine (CoPC) respectively. The enzyme glucose oxidase, that oxidases glucose, was used as sensing element and was immobilised on top of the gate electrodes. The sensor was fabricated with screen-printing, a low-cost technique that offers high throughput and is robust, simple and flexible. The gate electrodes were evaluated with cyclic voltammetry and chronoamperometry before integrated in the transistor device. The results showed that electrodes containing CoPC could detect hydrogen peroxide, a product in the reaction between glucose and the enzyme. Ferricyanide-electrodes showed good results regarding the activity of the mediator but no good results were achieved for the ferrocene-mediated electrodes. Transistor devices with CoPCmediated electrodes gave a response for 1mM hydrogen peroxide at 0.55V with good reproducibility, but the sensitivity needs to be further investigated. Transistor measurements with ferricyanide-mediated gates at 0.25V and glucose oxidase indicated that the glucose sensing works with these electrodes as well, but more measurements are needed. It was also concluded that the geometry of the transistor device had an influence on the relative response for the sensor, and a long channel proved to be better than a wide. The method used to fabricate the sensor offers great variation options and few production steps and the mediator approach enables inexpensive material costs.

  • 25.
    Keselman, Boris
    et al.
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Vergara Valgañon, Marta
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Nyberg, Sofia
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Nyström, Fredrik H
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Endocrinology.
    A randomized cross-over study of the acute effects of running 5 km on glucose, insulin, metabolic rate, cortisol and Troponin T2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 6, e0179401Article in journal (Refereed)
    Abstract [en]

    Background We aimed to study the impact by running 5 km, at maximal speed, on the normal variations of metabolic variables related to glucose, insulin, insulin sensitivity, cortisol, glucagon, Troponin T and metabolic rate. Material and methods Five women and 12 men 25.7 +/- 5.2 years of age with a body-mass-index of 22.5 +/- 2.3 kg/m(2) where recruited to run 5 km at individual maximal speed in the morning, and to a corresponding day of rest, followed by standardized breakfast and lunch meals. Blood sampling and measurement of indirect calorimetry were done before and after meals. The participants were randomized regarding the order of the two trial-days in this cross-over study. Results Insulin and cortisol levels were higher, and insulin sensitivity was lower, on the race-day compared with the day of rest (linear mixed model: pamp;lt;0.0001 for all three analyses). However, glucose levels and metabolic rate did not differ between the two trial days (p = 0.29 and p = 0.53, respectively). When analyzing specific time-points we found that glucose increased from 5.01 +/- 0.37 mmol/l to 6.36 +/- 1.3 mmol/l, pamp;lt;0.0001, by running, while serum insulin concomitantly increased from 42 21 to 90 54 pmo1/1, pamp;lt;0.0001. In accordance, the QUICKI index of serum sensitivity, 1/(log(10)insulin+log(10)glucose), was lowered post-race, pamp;lt;0.0001. Serum cortisol levels increased from 408 137 nmol/l to 644 171 nmol/l, pamp;lt;0.0001, post-race while serum glucagon levels were unaffected. Troponin T was detectable in serum post-race in 12 out of the 17 participants and reached or surpassed the clinical reference level of 15 ng/l in three subjects. Post-race electrocardiograms displayed no pathologies. Conclusions Relatively short running-races can apparently induce a reduction in insulin sensitivity that is not fully compensated by concomitantly increased insulin secretion intended to ensure euglycemia. Since also Troponin T was detected in plasma in a majority of the participants, our data suggest that it is possible to induce considerable metabolic stress by running merely 5 km, when striving for maximal speed.

  • 26.
    Fernemark, Hanna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Jaredsson, Christine
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Bunjaku, Bekim
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Rosenqvist, Ulf
    Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Research & Development Unit in Local Health Care.
    Nyström, Fredrik H
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Endocrinology.
    Guldbrand, Hans
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    A Randomized Cross-Over Trial of the Postprandial Effects of Three Different Diets in Patients with Type 2 Diabetes2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 11, e79324- p.Article in journal (Refereed)
    Abstract [en]

    Background: In the clinic setting both fasting levels of glucose and the area under the curve (AUC) of glucose, by determination of HbA1c levels, are used for risk assessments, in type 2 diabetes (NIDDM). However little is known about postprandial levels, and hence AUC, regarding other traditional risk factors such as insulin and blood-lipids and how this is affected by different diets. less thanbrgreater than less thanbrgreater thanObjective: To study postprandial effects of three diets, during a single day, in NIDDM. less thanbrgreater than less thanbrgreater thanMethods: A low-fat diet (45-56 energy-% from carbohydrates), and a low-carbohydrate diet (16-24 energy-% from carbohydrates) was compared with a Mediterranean-style diet (black coffee for breakfast and the same total-caloric intake as the other two diets for lunch with red wine, 32-35 energy-% from carbohydrates) in a randomized cross-over design. Total-caloric intake/test-day at the clinic from food was 1025-1080 kCal in men and 905-984 kCal in women. The test meals were consumed at a diabetes ward under supervision. less thanbrgreater than less thanbrgreater thanResults: Twenty-one participants were recruited and 19 completed the studies. The low-carbohydrate diet induced lower insulin and glucose excursions compared with the low-fat diet (pandlt;0.0005 for both AUC). The insulin-response following the single Mediterranean-style lunch-meal was more pronounced than during the low-fat diet lunch (insulin increase-ratio of the low-fat diet: 4.35 +/- 2.2, of Mediterranean-style diet: 8.12 +/- 5.2, p=0.001) while postprandial glucose levels were similar. The increase-ratio of insulin correlated with the elevation of the incretin glucose-dependent insulinotropic-polypeptide following the Mediterranean-style diet lunch (Spearman, r = 0.64, p = 0.003). less thanbrgreater than less thanbrgreater thanConclusions: The large Mediterranean-style lunch-meal induced similar postprandial glucose-elevations as the low-fat meal despite almost double amount of calories due to a pronounced insulin-increase. This suggests that accumulation of caloric intake from breakfast and lunch to a single large Mediterranean style lunch-meal in NIDDM might be advantageous from a metabolic perspective.

  • 27.
    Baloach, Qurrat-ul-Ain
    et al.
    University of Sindh, Pakistan.
    Tahira, Aneela
    University of Sindh, Pakistan.
    Begum Mallah, Arfana
    University of Sindh, Pakistan.
    Ishaq Abro, Muhammad
    Mehran University of Engn and Technology, Pakistan.
    Uddin, Siraj
    University of Sindh, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    A Robust, Enzyme-Free Glucose Sensor Based on Lysine-Assisted CuO Nanostructures2016In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, no 11, 1878Article in journal (Refereed)
    Abstract [en]

    The production of a nanomaterial with enhanced and desirable electrocatalytic properties is of prime importance, and the commercialization of devices containing these materials is a challenging task. In this study, unique cupric oxide (CuO) nanostructures were synthesized using lysine as a soft template for the evolution of morphology via a rapid and boiled hydrothermal method. The morphology and structure of the synthesized CuO nanomaterial were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The prepared CuO nanostructures showed high potential for use in the electrocatalytic oxidation of glucose in an alkaline medium. The proposed enzyme-free glucose sensor demonstrated a robust response to glucose with a wide linear range and high sensitivity, selectivity, stability, and reproducibility. To explore its practical feasibility, the glucose content of serum samples was successfully determined using the enzyme-free sensor. An analytical recovery method was used to measure the actual glucose from the serum samples, and the results were satisfactory. Moreover, the presented glucose sensor has high chemical stability and can be reused for repetitive measurements. This study introduces an enzyme-free glucose sensor as an alternative tool for clinical glucose quantification.

  • 28.
    Hahn, Robert
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Ljunggren, Stefan
    Södertalje Hospital.
    Larsen, Filip
    Karolinska Institute.
    Nystrom, Thomas
    Karolinska Institute.
    A simple intravenous glucose tolerance test for assessment of insulin sensitivity2011In: Theoretical Biology Medical Modelling, ISSN 1742-4682, Vol. 8, no 12Article in journal (Refereed)
    Abstract [en]

    Background

    The aim of the study was to find a simple intravenous glucose tolerance test (IVGTT) that can be used to estimate insulin sensitivity.

    Methods

    In 20 healthy volunteers aged between 18 and 51 years (mean, 28) comparisons were made between kinetic parameters derived from a 12-sample, 75-min IVGTT and the Mbw (glucose uptake) obtained during a hyperinsulinemic euglycemic glucose clamp. Plasma glucose was used to calculate the volume of distribution (Vd) and the clearance (CL) of the injected glucose bolus. The plasma insulin response was quantified by the area under the curve (AUCins). Uptake of glucose during the clamp was corrected for body weight (Mbw).

    Results

    There was a 7-fold variation in Mbw. Algorithms based on the slope of the glucose-elimination curve (CL/Vd) in combination with AUCins obtained during the IVGTT showed statistically significant correlations with Mbw, the linearity being r2 = 0.63-0.83. The best algorithms were associated with a 25-75th prediction error ranging from -10% to +10%. Sampling could be shortened to 30-40 min without loss of linearity or precision.

    Conclusion

    Simple measures of glucose and insulin kinetics during an IVGTT can predict between 2/3 and 4/5 of the insulin sensitivity.

  • 29.
    Bergqvist, Niclas
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Nyman, Elin
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering. AstraZeneca RandD, Sweden.
    Cedersund, Gunnar
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering. Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Stenkula, Karin G.
    Lund University, Sweden.
    A systems biology analysis connects insulin receptor signaling with glucose transporter translocation in rat adipocytes2017In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 292, no 27, 11206-11217 p.Article in journal (Refereed)
    Abstract [en]

    Type 2 diabetes is characterized by insulin resistance, which arises from malfunctions in the intracellular insulin signaling network. Knowledge of the insulin signaling network is fragmented, and because of the complexity of this network, little consensus has emerged for the structure and importance of the different branches of the network. To help overcome this complexity, systems biology mathematical models have been generated for predicting both the activation of the insulin receptor (IR) and the redistribution of glucose transporter 4 (GLUT4) to the plasma membrane. Although the insulin signal transduction between IR and GLUT4 has been thoroughly studied with modeling and time-resolved data in human cells, comparable analyses in cells from commonly used model organisms such as rats and mice are lacking. Here, we combined existing data and models for rat adipocytes with new data collected for the signaling network between IR and GLUT4 to create a model also for their interconnections. To describe all data (amp;gt;140 data points), the model needed three distinct pathways from IR to GLUT4: (i) via protein kinase B (PKB) and Akt substrate of 160 kDa (AS160), (ii) via an AS160-independent pathway from PKB, and (iii) via an additional pathway from IR, e.g. affecting the membrane constitution. The developed combined model could describe data not used for training the model and was used to generate predictions of the relative contributions of the pathways from IR to translocation of GLUT4. The combined model provides a systems-level understanding of insulin signaling in rat adipocytes, which, when combined with corresponding models for human adipocytes, may contribute to model-based drug development for diabetes.

  • 30.
    Ljunggren, Stefan
    et al.
    Södertälje Hospital, Sweden.
    Nyström, Thomas
    Karolinska Institutet, Södersjukhuset, Stockholm, Sweden.
    Hahn, Robert G
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping. Södertälje Hospital, Sweden.
    Accuracy and precision of commonly used methods for quantifying surgery-induced insulin resistance: Prospective observational study2014In: European Journal of Anaesthesiology, ISSN 0265-0215, E-ISSN 1365-2346, Vol. 31, no 2, 110-116 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Insulin resistance develops in the perioperative setting and has an adverse influence on postoperative recovery and well-being.

    OBJECTIVES: To evaluate the effectiveness of commonly used methods for quantifying surgery-induced insulin resistance.

    DESIGN: Prospective observational study.

    SETTING: Surgery department and orthopaedic ward at two regional hospitals.

    PATIENTS: Twenty-two patients (mean age 68 years) scheduled for elective hip replacement.

    INTERVENTIONS: A short seven-sample intravenous glucose tolerance test (IVGTT) followed by a euglycaemic hyperinsulinaemic glucose clamp 1 day before and 2 days after the surgery.

    MAIN OUTCOME MEASURES: Insulin resistance shown by dynamic tests (the IVGTT and the glucose clamp) were compared to static tests [the quantitative insulin sensitivity check index (QUICKI) and the homeostatic model assessment-insulin resistance (HOMA-IR)], which use only the plasma glucose and insulin concentrations at baseline.

    RESULTS: The linear correlation coefficients for the relationship between insulin resistance as obtained with the glucose clamp and the other methods before or after surgery were 0.76 (IVGTT), 0.58 (QUICKI) and -0.65 (HOMA). The prediction errors (precision) averaged 18, 29 and 31%, respectively. Surgery-induced insulin resistance amounted to 45% (glucose clamp), 26% (IVGTT), 4% (QUICKI) and 3% (HOMA).

    CONCLUSION: Despite reasonably good linear correlations, the static tests grossly underestimated the degree of insulin resistance that developed in response to surgery.

  • 31.
    Lundström, Patrik
    et al.
    University of Toronto, Departments of Biochemistry, Chemistry and Medical Genetics.
    Hansen, D. Flemming
    University of Toronto, Departments of Biochemistry, Chemistry and Medical Genetics.
    Vallurupalli, Parmodh
    University of Toronto, Departments of Biochemistry, Chemistry and Medical Genetics.
    Kay, Lewis E.
    University of Toronto, Departments of Biochemistry, Chemistry and Medical Genetics.
    Accurate Measurement of Alpha Proton Chemical Shifts of Excited Protein States by Relaxation Dispersion NMR Spectroscopy2009In: Journal of the American Chemical Society, ISSN 0002-7863, Vol. 131, no 5, 1915-1926 p.Article in journal (Refereed)
    Abstract [en]

    Carr-Purcell-Meiboom-Gill relaxation dispersion NMR spectroscopy can provide detailed information about low populated, invisible states of protein molecules, including backbone chemical shifts of the invisible conformer and bond vector orientations that can be used as structural constraints. Notably, the measurement of H-1(alpha) chemical shifts in excited protein states has not been possible to date because, in the absence of suitable labeling, the homonuclear proton scalar coupling network in side chains of proteins leads to a significant degradation in the performance of proton-based relaxation dispersion experiments. Here we have overcome this problem through a labeling scheme in which proteins are prepared with U-H-2 glucose and 50% D2O/50% H2O that results in cleuteration levels of between 50-88% at the C-beta carbon. Effects from residual H-1(alpha)-H-1(beta) scalar couplings can be suppressed through a new NMR experiment that is presented here. The utility of the methodology is demonstrated on a ligand binding exchanging system and it is shown that H-1(alpha) chemical shifts extracted from dispersion profiles are, on average, accurate to 0.03 ppm, an order of magnitude better than they can be predicted from structure using a database approach. The ability to measure H-1(alpha) chemical shifts of invisible conformers is particularly important because such shifts are sensitive to both secondary and tertiary structure. Thus, the methodology presented is a valuable addition to a growing list of experiments for characterizing excited protein states that are difficult to study using the traditional techniques of structural biology.

  • 32.
    Osikoya, Adeniyi
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Vanderbijlpark, South Africa.
    Parlak, Onur
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Murugan, N .Arul
    Stockholm, Sweden.
    Dikio, Ezekiel Dixon
    Vanderbijlpark, South Africa.
    Moloto, Harry
    Vanderbijlpark, South Africa.
    Uzun, Lokman
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Department of Chemistry, Hacettepe University, Ankara, Turkey.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. UCS, Tekidag AB, Linkoping,, Sweden; Vinoba Bhave Research Institute, Sirsa Road, Saidabad, Allahabad 221508, India.
    Acetylene-sourced CVD-synthesised catalytically active graphene for electrochemical biosensing.2017In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 89, 496-504 p.Article in journal (Refereed)
    Abstract [en]

    In this study, we have demonstrated the use of a graphene sheet as a fundamental building block to obtain a highly ordered graphene-enzyme electrode for electrochemical biosensing. Firstly, thin graphene sheets were deposited on 1.00 mm thick copper sheet at 850 oC, via chemical vapour deposition (CVD), using acetylene (C2H2) as carbon source in an argon (Ar) and nitrogen (N2) atmosphere. An anionic surfactant was used to introduce electrostatic charges and increase wettability and hydrophilicity on the basal plane of the otherwise hydrophobic graphene, thereby facilitating the assembly of biomolecules on the graphene surface. The bioelectrocatalytic activity of the system was investigated by the assembly of glucose oxidase (GOx) on the surface of the graphene sheet by intermolecular attractive forces. The electrochemical sensing activity of the graphene-based system was explored as a model for bioelectrocatalysis. The bioelectrode exhibited a linear response to glucose concentration from 0.2 to 9.8 mM, with sensitivity of 0.087 µA/µM/cm2 and a detection limit of 0.12 µM (S/N=3). This work sets the stage for the use of acetylene-sourced graphene sheets as fundamental building blocks in the fabrication of electrochemical biosensors and other biocatalytic devices.

  • 33.
    Dahlfors, Gunilla
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Action and interaction of growth factors and regulatory molecules in vascular cells: With special reference to the IGF-I-system2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Vascular function is greatly influenced by growth factors and regulatory molecules that can interact with each other in a complex pattern in the vascular wall. In this thesis we studied how different substances of special interest in the pathogenesis of vascular disease interact and regulate each other's expressions in endothelial cells and vascular smooth muscle cells (VSMCs).

    In VSMCs, angiotensin II was shown to delay PDGF-BB induced cell growth. This transient inhibitory effect of angiotensin II was mediated by the AT1-receptor, did not involve autocrine action of transforming growth factor-ß1 (TGF-ß1) and acted at a site downstream of PDGF-ß receptor phosphorylation.

    The interaction of the insulin-like growth factor-system (IGF-system) with various growth factors, glucose and nitric oxide (NO) was studied in vascular cells. Vascular endothelial growth factor (VEGF) and transforming growth factor-ß1 (TGF-ß1) regulated the expression of insulin-like growth factor-binding proteins (IGFBPs) in large vessel endothelial cells in a way that might cause an increased bioavailability of IGF-I locally in the subendothelial space. Angiotensin II, IGF-I and insulin did not affect IGFBP expression in these cells. The expression of IGFBPs was studied for the first time in human micro vessel endothelial cells. No effect of high glucose treatment on IGFBP expression was seen in either large vessel endothelial cells or microvessel endothelial cells. A possible interaction between NO and the IGF-system was studied in VSMCs. IGF-I did not have any significant effect on NO production in VSMCs and neither exogenous nor endogenous NO had any effect on IGFBP expression.

    In conclusion, we found that angiotensin II interacts with PDGF-BB in the regulation of VSMC growth. The IGF-system is regulated by VEGF and TGF-ß1 in endothelial cells while no effect of angiotensin II, IGF-I, insulin or high glucose was seen. We found no evidence for interaction of NO and the IGF-system in VSMCs.

    List of papers
    1. PDGF-BB-induced DNA synthesis is delayed by angiotensin II in vascular smooth muscle cells
    Open this publication in new window or tab >>PDGF-BB-induced DNA synthesis is delayed by angiotensin II in vascular smooth muscle cells
    1998 (English)In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 274, no 5, H1742-H1748 p.Article in journal (Refereed) Published
    Abstract [en]

    The interaction of ANG II with platelet-derived growth factor (PDGF)-BB-induced DNA synthesis was studied in cultured rat aortic smooth muscle cells. PDGF-BB-induced DNA synthesis was delayed (∼6–8 h) by ANG II as shown by a time-course experiment. Losartan, an AT1-receptor antagonist, blocked the transient inhibitory effect of ANG II, whereas the AT2-receptor antagonist PD-123319 had no effect. Autocrine- or paracrine-acting transforming growth factor-β1 (TGF-β1), believed to be a mediator of ANG II-induced inhibitory effects, was not responsible for the delay of PDGF-BB-induced DNA synthesis, because a potent TGF-β1 neutralizing antibody could not reverse this effect of ANG II, nor was the delay of the PDGF-BB effect caused by inhibition of PDGF-β-receptor phosphorylation as shown by Western blot analysis of immunoprecipitated PDGF-β receptor. In conclusion, our results show that ANG II can exert a transient inhibitory effect on PDGF-BB-induced proliferation via the AT1 receptor.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-79727 (URN)
    Available from: 2012-08-13 Created: 2012-08-13 Last updated: 2012-08-13Bibliographically approved
    2. Vascular Endothelial Growth Factor and Transforming Growth Factor-β1 Regulate the Expression of Insulin-Like Growth Factor-Binding Protein-3, -4, and -5 in Large Vessel Endothelial Cells
    Open this publication in new window or tab >>Vascular Endothelial Growth Factor and Transforming Growth Factor-β1 Regulate the Expression of Insulin-Like Growth Factor-Binding Protein-3, -4, and -5 in Large Vessel Endothelial Cells
    2000 (English)In: Endocrinology, ISSN 0013-7227, E-ISSN 1945-7170, Vol. 141, no 6, 2062-2067 p.Article in journal (Refereed) Published
    Abstract [en]

    We investigated the effect of diabetes-associated growth factors on the expression of insulin-like growth factor-I (IGF-I) and IGF-binding proteins (IGFBPs) in cultured endothelial cells from bovine aorta. Gene expression was measured by solution hybridization, and proteins were measured by enzyme-linked immunosorbent assay, RIA, or Western blot. The cells expressed messenger RNA (mRNA) for IGFBP-2 through -6 and IGFBP-2 through -5 proteins were detected in conditioned medium. Vascular endothelial growth factor inhibited IGFBP-3 mRNA (P < 0.01) and protein expression and increased IGFBP-5 mRNA (P < 0.001) and protein. Transforming growth factor-β1 inhibited IGFBP-3 (P < 0.01), IGFBP-4 (P < 0.01), and IGF-I mRNA expression, whereas at the protein level only IGFBP-3 was significantly decreased. IGF-I, insulin, or angiotensin II did not affect IGF-I or IGFBP mRNA expression. At the protein level, IGF-I clearly increased IGFBP-5 levels in conditioned medium. In conclusion, vascular endothelial growth factor and transforming growth factor-β1 regulate IGFBP expression in bovine aortic endothelial cells. These observations provide a new aspect of regulation for the IGF-system in macrovascular endothelium, with possible implications for subendothelial smooth muscle cells and development of diabetic angiopathy.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-24909 (URN)10.1210/en.141.6.2062 (DOI)9312 (Local ID)9312 (Archive number)9312 (OAI)
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2012-08-13Bibliographically approved
    3. Expression of insulin-like growth factor binding proteins and transforming growth factor-ß1 in human microvascular endothelial and bovine aortic endothelial cells, no effects of high glucose
    Open this publication in new window or tab >>Expression of insulin-like growth factor binding proteins and transforming growth factor-ß1 in human microvascular endothelial and bovine aortic endothelial cells, no effects of high glucose
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Vascular complications are the major cause of morbidity and mortality in patients with diabetes mellitus. Insnlin-like growth factor-I (IGF-I) and transforming growth factor-ß1 (TGF-ß1) are two growth factors that regnlate vascular smooth muscle cell function in vivo and might be involved in the development of diabetic vascnlar complications. In this study we measnred the expression of IGF-binding proteins (IGFBPs) and TGF-ß1 in human dermal microvessel endothelial cells (HDMEC). We also studied the effect of high glucose levels on the expression of IGFBPs and TGF-ß1 in cnltured HDMEC and bovine aortic endothelial cells (BAEC). Gene expression was measured by an RNase-protection assay and proteins secreted into conditioned medium by ELISA or Western blot. The HDMEC expressed mRNAs for IGF-I and IGFBP-2 through -6 of which IGFBP-4 was the most excessively expressed and IGFBP-2 and -4 were detected in conditioned medium. Culture of HDMEC in high glucose (25 mM) for two passages did not change mRNA expressions for IGFBP-2, -3 or -4 significantly. Neither did low glucose+ mannitol (5.6 mM+ 20 mM) have any effect. In BAEC, high glucose (25 mM) for 48 h or 96 h did not affect IGFBP-3, -4 or -5 mRNA or protein and exposnre of BAEC to high glucose for two passages did also not affect IGFBP mRNA. TGF-ß1 mRNA was expressed by both BAEC and HDMEC. High glucose for two passages did not alter TGF-ß1 gene expression in either BAEC or HDMEC. In conclusion, we show that HDMEC express IGFBPs and TGF-ß1 andthat high glucose does not affect the expression in either HDMEC or BAEC.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-79728 (URN)
    Available from: 2012-08-13 Created: 2012-08-13 Last updated: 2012-08-13Bibliographically approved
    4. Effect of nitric oxide on vascular smooth muscle cell proliferation and insulin-like growth factor binding protein expression
    Open this publication in new window or tab >>Effect of nitric oxide on vascular smooth muscle cell proliferation and insulin-like growth factor binding protein expression
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    A possible interaction between nitric oxide (NO) and the insulin-like growth factor (IGF)-system was studied in cultured rat aortic smooth muscle cells. The NO-donor SNAP markedly inhibited basal and sernm-induced DNA synthesis while addition of L-NAME, an inhibitor of endogenous NO production, had no effect. L-NAME did also not significantly affect IGF-I, angiotensin II or TGF-ß1- induced effects on DNA synthesis. IGF-I was shown to stimulate the expression of IGFBP-4 mRNA, as measured by an RNase-protection assay, and angiotensin II inhibited expression of IGFBP-2 mRNA. Addition of L-NAME did not significantly change the effect of IGF-I or angiotensin II on IGFBP mRNA expression, neither did L-NAME or SNAP affect basal expression of IGFBP-2, -4 or -6 mRNA. In conclusion, we found no evidence for interaction of NO with the IGF-system in smooth muscle cells. Nitric oxide did not regulate the expression of IGFBPs and IGF-I-induced smooth muscle cell proliferation was not affected by inhibition of endogenous NO production.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-79729 (URN)
    Available from: 2012-08-13 Created: 2012-08-13 Last updated: 2012-08-13Bibliographically approved
  • 34.
    ONeill, Julie
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Fasching, Angelica
    Uppsala University, Sweden.
    Pihl, Liselotte
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Patinha, Daniela
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Franzén, Stephanie
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Palm, Fredrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Uppsala University, Sweden.
    Acute SGLT inhibition normalizes O-2 tension in the renal cortex but causes hypoxia in the renal medulla in anaesthetized control and diabetic rats2015In: American Journal of Physiology - Renal Physiology, ISSN 1931-857X, E-ISSN 1522-1466, Vol. 309, no 3, F227-F234 p.Article in journal (Refereed)
    Abstract [en]

    Early stage diabetic nephropathy is characterized by glomerular hyperfiltration and reduced renal tissue PO2. Recent observations have indicated that increased tubular Na+-glucose linked transport (SGLT) plays a role in the development of diabetes-induced hyperfiltration. The aim of the present study was to determine how inhibition of SLGT impacts upon PO2 in the diabetic rat kidney. Diabetes was induced by streptozotocin in Sprague-Dawley rats 2 wk before experimentation. Renal hemodynamics, excretory function, and renal O-2 homeostasis were measured in anesthetized control and diabetic rats during baseline and after acute SGLT inhibition using phlorizin (200 mg/kg ip). Baseline arterial pressure was similar in both groups and unaffected by SGLT inhibition. Diabetic animals displayed reduced baseline PO2 in both the cortex and medulla. SGLT inhibition improved cortical PO2 in the diabetic kidney, whereas it reduced medullary PO2 in both groups. SGLT inhibition reduced Na+ transport efficiency [tubular Na+ transport (TNa)/renal O-2 consumption (QO(2))] in the control kidney, whereas the already reduced TNa/QO(2) in the diabetic kidney was unaffected by SGLT inhibition. In conclusion, these data demonstrate that when SGLT is inhibited, renal cortex PO2 in the diabetic rat kidney is normalized, which implies that increased proximal tubule transport contributes to the development of hypoxia in the diabetic kidney. The reduction in medullary PO2 in both control and diabetic kidneys during the inhibition of proximal Na+ reabsorption suggests the redistribution of active Na+ transport to less efficient nephron segments, such as the medullary thick ascending limb, which results in medullary hypoxia.

  • 35.
    Eriksson, Andreas C
    et al.
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Whiss, Per A
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Nilsson, Ulrika K
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Adhesion of human platelets to albumin is synergistically increased by lysophosphatidic acid and adrenaline in a donor-dependent fashion2006In: Blood Coagulation and Fibrinolysis, ISSN 0957-5235 (print), 1473-5733 (online), Vol. 17, no 5, 359-368 p.Article in journal (Refereed)
    Abstract [en]

    Lysophosphatidic acid (LPA) and adrenaline are weak platelet activators considered important for thrombus formation, and were previously shown to synergistically increase platelet aggregation. Here we investigate synergistic activation by LPA and adrenaline when measuring platelet adhesion. Platelet-rich plasma from healthy blood donors together with adrenaline and/or LPA were added to protein-coated microplates. Platelets were allowed to adhere and the amount of adhesion detected enzymatically. The LPA and adrenaline combination induced a synergistic increase of platelet adhesion to a normally non-adhesive albumin surface. The degree of synergy varied markedly between individuals; these variations could not be explained by age, gender, blood type or different amounts of platelets, oxidized low-density lipoprotein, insulin or glucose in plasma. There was a trend indicating increased synergistic effect for platelets sensitive to adrenaline stimulation. The synergistic effect was blocked by the α2-adrenoceptor antagonist yohimbine and inhibited by the ADP scavenger system creatine phosphate/creatine phosphokinase and antibodies against αIIbβ3. Furthermore, platelets adhering to albumin after adrenaline and LPA treatment expressed P-selectin. In conclusion, LPA and adrenaline act synergistically to increase αIIbβ3-mediated platelet adhesion to albumin, dependent on α2-adrenoceptor signalling and platelet secretion. We also confirm that synergistic platelet activation achieved with LPA and adrenaline is highly donor dependent.

  • 36. Pavasars, I
    et al.
    Hagberg, J
    Borén, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Analytical Chemistry .
    Allard, B
    Alkaline degradation of cellulose: Mechanisms and kinetics2003In: Journal of polymers and the environment, ISSN 1566-2543, Vol. 11, no 2, 39-47 p.Article in journal (Refereed)
    Abstract [en]

    Cellulose powder and softwood sawdust were subjected to alkaline degradation under conditions representative of a cementitious environment for periods of 7 and 3 years, respectively. During the first 3 years, sampling was frequent, and data on the degradation of cellulose and production of isosaccharinic acid was used for establishing long-term prediction models. Samples after an additional period of 4 years were compared to the predicted values. The total rate of degradation was measured as the increase in total organic carbon (TOC) in corresponding solutions. A previously published theoretical model of degradation kinetics gave a good approximation of the present experimental data. Peeling-off, stopping, and alkaline hydrolysis reaction rate constants were obtained as model parameters, and the results suggested that the transformation of the glucose end group is the rate-limiting step in the cellulose peeling-off reaction and also determines the pH dependence of that reaction. After 3 years, isosaccharinic (ISA) acid represented 70-85% of all degradation products as quantified by capillary zone electrophoresis. The long-term prediction model indicated that all of the cellulose would be degraded after only 150-550 years. The control sampling after 7 years points toward a lower degradation of cellulose and production of ISA than predicted by the model, reflecting either a degradation of ISA that was faster than the production or a termination of the ISA production.

  • 37.
    Morales Drissi, Natasha
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Szakacs, Attila
    University of Gothenburg, Sweden.
    Witt, Suzanne
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    Wretman, Anna
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Ulander, Martin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Clinical Neurophysiology.
    Ståhlbrandt, Henriettae
    Highland Hospital, Sweden.
    Darin, Niklas
    University of Gothenburg, Sweden.
    Hallbook, Tove
    University of Gothenburg, Sweden.
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Uppsala University, Sweden.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Altered Brain Microstate Dynamics in Adolescents with Narcolepsy2016In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 10, no 369Article in journal (Refereed)
    Abstract [en]

    Narcolepsy is a chronic sleep disorder caused by a loss of hypocretin-1 producing neurons in the hypothalamus. Previous neuroimaging studies have investigated brain function in narcolepsy during rest using positron emission tomography (PET) and single photon emission computed tomography (SPECT). In addition to hypothalamic and thalamic dysfunction they showed aberrant prefrontal perfusion and glucose metabolism in narcolepsy. Given these findings in brain structure and metabolism in narcolepsy, we anticipated that changes in functional magnetic resonance imaging (fMRI) resting state network (RSN) dynamics might also be apparent in patients with narcolepsy. The objective of this study was to investigate and describe brain microstate activity in adolescents with narcolepsy and correlate these to RSNs using simultaneous fMRI and electroencephalography (EEG). Sixteen adolescents (ages 13-20) with a confirmed diagnosis of narcolepsy were recruited and compared to age-matched healthy controls. Simultaneous EEG and fMRI data were collected during 10 min of wakeful rest. EEG data were analyzed for microstates, which are discrete epochs of stable global brain states obtained from topographical EEG analysis. Functional fMRI data were analyzed for RSNs. Data showed that narcolepsy patients were less likely than controls to spend time in a microstate which we found to be related to the default mode network and may suggest a disruption of this network that is disease specific. We concluded that adolescents with narcolepsy have altered resting state brain dynamics.

  • 38.
    Banerjee, S
    et al.
    Department of Polymer Science and Technology, University of Calcutta, India.
    Sarkar, Priya
    Department of Polymer Science and Technology, University of Calcutta, India.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Amperometric Biosensor for estimation of Glucose-6-phosphate Using Prussian Blue Nanoparticles.2013In: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 439, no 2, 194-200 p.Article in journal (Refereed)
    Abstract [en]

    Glucose-6-phosphateplays an important role in carbohydrate metabolism of all living organisms.Compared to the conventional analytical methods available for estimation of glucose-6-phosphate,the biosensors having relative simplicity, specificity, low-cost and fastresponse time are a promising alternative. We have reported a glucose-6-phosphatesensor based on screen-printed electrode utilizing Prussian blue nanoparticlesand enzymes, glucose-6-phosphate dehydrogenase and glutathione reductase. The Prussianblue nanoparticles acted as a mediator enhancing the rate of electrochemical responses.The Fourier transforminfrared spectroscopy and energy-dispersiveX-ray spectroscopy study confirmed the formation of Prussian blue, whereas, the atomic forced microscopy revealed that Prussian bluenanoparticles were about 25-30 nm in diameter. To obtainmaximum amperometric response, optimization studies were conducted for pH,enzyme and cofactor loading. The proposed glucose-6-phosphate biosensor showed goodstability, rapid response time and broad linear response in the range of 0.01-1.25mM and detection limit of 6.3 mM. The biosensor also worked well for serum samples and exhibitedexcellent anti-interference ability.

  • 39.
    Turner, Anthony
    et al.
    Cranfield University, UK.
    and six more authors,
    Amperometric enzyme electrode for glucose determination1984In: Charge and Field Effects in Biosystems / [ed] M.J. Allen and P.N.R. Usherwood, Abacus Press , 1984, 475-482 p.Chapter in book (Refereed)
  • 40.
    Baloach, Qurrat-ul-ain
    et al.
    University of Sindh, Pakistan.
    Nafady, Ayman
    King Saud University, Saudi Arabia; Sohag University, Egypt.
    Tahira, Aneela
    University of Sindh, Pakistan.
    Tufail Hussain Sirajuddin; Sherazi, Syed
    University of Sindh, Pakistan.
    Shaikh, Tayyaba
    University of Sindh, Pakistan.
    Arain, Munazza
    University of Sindh, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    An amperometric sensitive dopamine biosensor based on novel copper oxide nanostructures2017In: Microsystem Technologies: Micro- and Nanosystems Information Storage and Processing Systems, ISSN 0946-7076, E-ISSN 1432-1858, Vol. 23, no 5, 1229-1235 p.Article in journal (Refereed)
    Abstract [en]

    It is highly important to explore the influence of counter anions on the morphology in order to have a desired nanostructure with unique properties. Therefore, in this research work the influence of counter anions on the morphology of copper oxide (CuO) nanostructures is presented using copper chloride and copper acetate salts. A significant role of counter anions on the morphology of CuO nanostructures is observed. The hydrothermal method is used to carry out the synthesis of CuO nanomaterial. The prepared CuO nanostructures are characterized by scanning electron microscopy and X-ray diffraction techniques. The prepared CuO nanomaterial exhibits porous nature with thin nanowires and sponge like morphologies. The dopamine sensing application was carried for exploring the electrocatalytic properties of CuO nanostructures. The presented dopamine biosensor exhibited wide linear range for detection of dopamine from 5 to 40 A mu M with sensitivity of 12.8 A mu A mM(-1) cm(-2). The limit of detection and limit of quantification were estimated in order 0.11 and 0.38 A mu M respectively. The developed dopamine biosensor is highly sensitive, selective, stable and reproducible. The common interfering species such as glucose, ascorbic acid and uric acid showed negligible change in the current when same concentration of dopamine and these interfering species was used. The fabricated biosensor could be used for the determination of dopamine from real blood samples.

  • 41.
    MORRIS, NA
    et al.
    CRANFIELD INST TECHNOL,CTR BIOTECHNOL,CRANFIELD MK43 0AL,BEDS,ENGLAND; PAISLEY COLL TECHNOL,DEPT BIOL,PAISLEY PA1 2BE,RENFREW,SCOTLAND; UNILEVER RES,COLWORTH LAB,SHARNBROOK MK44 1LQ,BEDS,ENGLAND; .
    CARDOSI, MF
    CRANFIELD INST TECHNOL,CTR BIOTECHNOL,CRANFIELD MK43 0AL,BEDS,ENGLAND; PAISLEY COLL TECHNOL,DEPT BIOL,PAISLEY PA1 2BE,RENFREW,SCOTLAND; UNILEVER RES,COLWORTH LAB,SHARNBROOK MK44 1LQ,BEDS,ENGLAND; .
    BIRCH, BJ
    CRANFIELD INST TECHNOL,CTR BIOTECHNOL,CRANFIELD MK43 0AL,BEDS,ENGLAND; PAISLEY COLL TECHNOL,DEPT BIOL,PAISLEY PA1 2BE,RENFREW,SCOTLAND; UNILEVER RES,COLWORTH LAB,SHARNBROOK MK44 1LQ,BEDS,ENGLAND; .
    TURNER, APF
    Cranfield University, UK.
    AN ELECTROCHEMICAL CAPILLARY FILL DEVICE FOR THE ANALYSIS OF GLUCOSE INCORPORATING GLUCOSE-OXIDASE AND RUTHENIUM(III) HEXAMINE AS MEDIATOR1992In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 4, no 1Article in journal (Refereed)
    Abstract [en]

    This article describes a coulometric measurement device for glucose based on thin-layer bulk electrolysis. The analysis is carried out in a specially constructed cell, the electrochemical capillary fill device, which has a total volume of less than 20-mu-l. Once the sample enters the cell by capillary action, the freeze-dried assay components (glucose oxidase, ruthenium (III) hexamine, buffer salts, etc.) become solubilized and quickly disperse throughout the volume of the cell. After a period of one min, the time taken for the enzyme catalyzed oxidation of glucose to gluconic acid to reach completion, a potential step is applied and the current transient, resulting from the oxidation of reduced mediator at the working electrode, integrated over a period of 60 s. From the resultant charge value, the concentration of glucose in the sample can be unambiguously determined. The response of the sensor is both linear and accurate over the range 2-30 mM, which covers the normally accepted range for blood glucose levels in diabetic patients. The second order rate constant for the reaction between reduced glucose oxidase and ruthenium (III) hexamine was evaluated by conducting a numerically based analysis that was designed to separate the diffusional and catalytic components of current transients.

  • 42.
    Khun, Kimleang
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Mansor, N. A.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    An Electrochemical Dopamine Sensor Based on the ZnO/CuO Nanohybrid Structures2014In: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, Vol. 14, no 9, 6646-6652 p.Article in journal (Refereed)
    Abstract [en]

    The selective detection of dopamine (DA) is of great importance in the modern medicine because dopamine is one of the main regulators in human behaviour. In this study, ZnO/CuO nanohybrid structures, grown on the gold coated glass substrate, have been investigated as a novel electrode material for the electrochemical detection of dopamine. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were used for the material characterization and the obtained results are in good agreement. The selective determination of dopamine was demonstrated by cyclic voltammetry (CV) and amperometric experiments. The amperometric response was linear for dopamine concentrations between 1.0 x 10(-3) and 8.0 mM with a sensitivity of 90.9 mu A mM(-1) cm(-2). The proposed dopamine biosensor is very stable, selective over common interferents as glucose, uric acid and ascorbic acid, and also good reproducibility was observed for seven electrodes. Moreover, the dopamine sensor exhibited a fast response time of less than 10 s. The wide range and acceptable sensitivity of the presented dopamine sensor provide the possible application in analysing the dopamine from the real samples.

  • 43.
    HU, J
    et al.
    CRANFIELD INST TECHNOL,CTR BIOTECHNOL,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    TURNER, APF
    Cranfield University, UK.
    AN ENZYME ELECTRODE FOR GLUCOSE CONSISTING OF GLUCOSE-OXIDASE IMMOBILIZED AT A BENZOQUINONE-MODIFIED CARBON ELECTRODE1991In: Analytical Letters, ISSN 0003-2719, E-ISSN 1532-236X, Vol. 24, no 1, 15-24 p.Article in journal (Refereed)
    Abstract [en]

    This paper describes an amperometric enzyme electrode for the analysis of glucose. The glucose sensor utilised adsorbed benzoquinone on a carbon electrode to mediate electron transfer from glucose oxidase. A linear response to 0-15 mM glucose was observed. The electrodes response to glucose, its pH profile and the effect of temperature are presented.

  • 44.
    Fulati, Alimujiang
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Usman Ali, Syed M.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Asif, Muhammad H.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Pakistan.
    Hassan Alvi, Naveed Ul
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Brännmark, Cecilia
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Börjesson, Sara I.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Elinder, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Danielsson, Bengt
    Lund University, Sweden.
    An intracellular glucose biosensor based on nanoflake ZnO2010In: Sensors and actuators. B, Chemical, ISSN 0925-4005, Vol. 150, no 2, 673-680 p.Article in journal (Other academic)
    Abstract [en]

    In this study, an improved potentiometric intracellular glucose biosensor was fabricated with immobilization of glucose oxidase on a ZnO nanoporous material. The ZnO nanoporous material with a wall thickness around 200 nm was grown on the tip of a borosilicate glass capillary and used as a selective intracellular glucose sensor for the measurement of glucose concentrations in human adipocytes and frog oocytes. The results showed a fast response within 4 s and a linear glucosedependent electrochemical response over a wide range of glucose concentration (500 nM-10 mM). The measurements of intracellular glucose concentrations with our biosensor were consistent with the values of intracellular glucose concentrations reported in the literature. The sensor also demonstrated its capability by detecting an increase in the intracellular glucose concentration induced by insulin. We found that the ZnO nanoporous material provides sensitivity as high as 1.8 times higher than that obtained using ZnO nanorods under the same conditions. Moreover, the fabrication method in our experiment is simple and the excellent performance of the developed nanosensor in sensitivity, stability, selectivity, reproducibility and anti-interference was achieved. All these advantageous features of this intracellular glucose biosensor based on functionalised ZnO nanoporous material compared to ZnO nanorods demonstrate a promising way of enhancing glucose biosensor performance to measure reliable intracellular glucose concentrations within single living cells.

  • 45.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Anaerobic degradation of phenol and related aromatics2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Phenol and other simple aromatic compounds have been found in water leached from landfills, showing that these types of compounds could be either present in disposed waste, or released from it via transformation and degradation processes. Hence, the fate anddegradation potential of such compounds under landfilling conditions is of great concern. Therefore, using micro-organisms from landfills, I have investigated the anaerobic biodegradation of phenol, dimethyl phthalate, 3-chlorobenzoate, 2,4,6-trichlorophenol, tetrabromophthalic acid and aniline. The compounds were chosen to represent substrates of potentially important reactions in the transformation and degradation of aromatic compounds. 24 waste samples from landfills and a time series of samples taken over five years from fourlandfill simulation reactors (in all 20 waste samples) were used as sources of microorganisms. The capacity of these waste samples to degrade the halogenated aromatics was poor or completely absent, indicating that halogenated compounds could be more persistent inlandfills than in other previously investigated anaerobic environments. Phenol and dimethyl phthalate were more readily transformed by most landfill samples, but the degradation capacity was poorer in the landfill simulation experiments. Here the unique sampling series showed an increase in degradation capacity with time, indicating that one to two years is needed to allow a micro-flora capable of degrading aromatic compounds to develop. However, the landfill samples showed higher degradation potentials than the simulation reactor samples, even from the later stages.

    A more extensive study designed to elucidate the phenol degradation pathway under anaerobic, fermenting conditions is also presented. Here, phenol was for the first time shown to be degraded to non-aromatic products in a non-methanogenic fermenting culture. The endproductsformed were benzoate, acetate and butyrate. The conversion of phenol to benzoate was proved to be an electron sink reaction, used during processes such as degradation of glucose and is a new example of the diversity of compounds that can used as electronsinks/ acceptors in anaerobic environments. The degradation pathway in the studied cultureproceeds via fom1ation of 4-hydroxybenzoate, 4-hydroxybenzoyl-CoA and benzoyl-CoA, and the activity of a CoA-transferase which activates 4-hydroxybenzoate was measured.

    List of papers
    1. Anaerobic degradation of xenobiotics by organisms from munical solid waste under landfilling conditions
    Open this publication in new window or tab >>Anaerobic degradation of xenobiotics by organisms from munical solid waste under landfilling conditions
    Show others...
    1995 (English)In: Antonie van Leeuwenhoek. International Journal of General and Molecular Microbiology, ISSN 0003-6072, E-ISSN 1572-9699, Vol. 69, no 1, 67-74 p.Article in journal (Refereed) Published
    Abstract [en]

    The potential for biological transformation of 23 xenobiotic compounds by microorganisms in municipal solid waste (MSW) samples from a laboratory scale landfill reactor was studied. In addition the influence of these xenobiotic compounds on methanogenesis was investigated. All R11, 1,1 dichloroethylene, 2,4,6 trichlorophenol, dimethyl phthalate, phenol, benzoate and phthalic acid added were completely transformed during the period of incubation (> 100 days). Parts of the initially added perchloroethylene, trichloroethylene, R12, R114, diethyl phthalate, dibutyl phthalate and benzylbutyl phthalate were transformed. Methanogenesis from acetate was completely inhibited in the presence of 2,5 dichlorophenol, whereas 2,4,6 trichlorophenol and R11 showed an initial inhibition, whenafter methane formation recovered. No transformation or effect on the anaerobic microflora occurred for R13, R22, R114, 3 chlorobenzoate, 2,4,6 trichlorobenzoate, bis(2 ethyl)hexyl phthalate, diisodecyl phthalate and dinonyl phthalate. The results indicate a limited potential for degradation, of the compounds tested, by microorganisms developing in a methanogenic landfill environment as compared with other anaerobic habitats such as sewage digestor sludge and sediments.

    Keyword
    biodegradation, chlorinated compounds, freons, methane formation, phthalic acid esters, phenol
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-31281 (URN)10.1007/BF00641613 (DOI)17042 (Local ID)17042 (Archive number)17042 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2012-06-29Bibliographically approved
    2. Degradation of aromatic compounds by micro-organisms in solid waste samples from landfills and landfill simulation reactors
    Open this publication in new window or tab >>Degradation of aromatic compounds by micro-organisms in solid waste samples from landfills and landfill simulation reactors
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The ability by micro-organisms developed in landfilled waste totransform phenol, dimethyl phthalate (DMP), aniline, tetrabromophthalic acid (TBPA), 3-chlorobenzoate (CB) and 2,4,6-trichlorophenol (TCP) was investigated using a method modified after ISO 17334. Forty-four solid waste samples from landfills and landfill simulation reactors (LSRs) were used. The LSRs were run over a five-year period and simulated acid and methanogenic landfill conditions. The biodegradability of each aromatic compound (0.5-0. 7 mM) was assayed over 100-200 days. The degradation capacity was monitored both by quantification of the aromatic compounds and by methane analysis

    The degradation capacity for the halogenated aromatics was poor or completely lacking by the landfill inocula investigated showing that this kind of compounds might persist in landfill. TCP inhibited both the methanogenic and fermentative micro-flora present in the waste samples, however, in early LSR assays no inhibition was observed. Phenol and DMP was transformed to non aromatic products in most assays. The biodegradation capacity towards these compounds increased over time in the LSR studies i.e. the acid and early methanogenic land fill phases had no or poor degradation capacity. These results indicates that the earlymethanogcnic tlora developing in landfills and landfill simulation reactors is different from the one later established by being less efficient in transformation of aromatic compounds but also less sensitive to aryl halides.

    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-79139 (URN)
    Available from: 2012-06-29 Created: 2012-06-29 Last updated: 2012-06-29Bibliographically approved
    3. Degradation of phenol under meso- and thermophilic, anaerobic conditions
    Open this publication in new window or tab >>Degradation of phenol under meso- and thermophilic, anaerobic conditions
    1998 (English)In: Anaerobe, ISSN 1075-9964, E-ISSN 1095-8274, Vol. 5, no 1, 25-35 p.Article in journal (Refereed) Published
    Abstract [en]

    Based on the results of preliminary studies on phenol degradation under mesophilic conditions with a mixed methanogenic culture, we proposed a degradation pathway in which phenol is fermented to acetate: Part of the phenol is reductively transformed to benzoate while the rest is oxidised, forming acetate as end product. According to our calculations, this should result in three moles of phenol being converted to two moles of benzoate and three moles of acetate (3phenol+2CO2+3H2O→3acetate+2benzoate): To assess the validity of our hypothesis concerning the metabolic pathway, we studied the transformation of phenol under mesophilic and thermophilic conditions in relation to the availability of hydrogen. Hence, methanogenic meso- and thermophilic cultures amended with phenol were run with or without an added over-pressure of hydrogen under methanogenic and non-methanogenic conditions. Bromoethanesulfonic acid (BES) was used to inhibit methanogenic activity. In the mesophilic treatments amended with only BES, about 70% of the carbon in the products found was benzoate. During the course of phenol transformation in these BES-amended cultures, the formation pattern of the degradation products changed: Initially nearly 90% of the carbon from phenol degradation was recovered as benzoate, whereas later in the incubation, in addition to benzoate formation, the aromatic nucleus degraded completely to acetate. Thus, the initial reduction of phenol to benzoate resulted in a lowering of H2levels, giving rise to conditions allowing the degradation of phenol to acetate as the end product. Product formation in bottles amended with BES and phenol occurred in accordance with the hypothesised pathway; however, the overall results indicate that the degradation of phenol in this system is more complex.

    During phenol transformation under thermophilic conditions, no benzoate was observed and no phenol was transformed in the BES-amended cultures. This suggests that the sensitivity of phenol transformation to an elevated partial pressure of H2is higher under thermophilic conditions than under mesophilic ones. The lack of benzoate formation could have been due to a high turnover of benzoate or to a difference in the phenol degradation pathway between the thermophilic and mesophilic cultures.

    Keyword
    phenol degradation, electronacceptor, acetate formation, meso and thermophilic conditions, methane formation
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-31040 (URN)10.1006/anae.1998.0187 (DOI)16748 (Local ID)16748 (Archive number)16748 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2012-06-29Bibliographically approved
    4. CO2-dependent fermentation of phenol to acetate, butyrate and benzoate by an anaerobic, pasteurised culture
    Open this publication in new window or tab >>CO2-dependent fermentation of phenol to acetate, butyrate and benzoate by an anaerobic, pasteurised culture
    2000 (English)In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 173, no 5-6, 398-402 p.Article in journal (Refereed) Published
    Abstract [en]

    Fermentative degradation of phenol was studied using a non-methanogenic, pasteurised enrichment culture containing two morphologically different bacteria. Phenol was fermented to benzoate, acetate and butyrate and their relative occurrence depended on the concentration of hydrogen. Proportionately more benzoate was formed with high initial levels of H2. The influence of P(H2) on the fermentation pattern was studied both in dense cell suspensions and in growing cultures by addition of hydrogen. An increase in growth yield (OD578 was observed, compared to controls, as a consequence of phenol degradation, however, the increase was less in H2-amended treatments, in which most of the phenol ended up as benzoate. The degradation of phenol in the dense cell suspension experiments was dependent on CO2. Benzoate was not degraded when added as a substrate to the growing culture. This is, to our knowledge, the first report concerning the fermentative degradation of phenol to nonaromatic products.

    Keyword
    Phenol fermentation, Reductive dehydroxylation, Hydrogen partial pressure, Ring cleavage
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-32080 (URN)10.1007/s002030000160 (DOI)17935 (Local ID)17935 (Archive number)17935 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2012-06-29Bibliographically approved
    5. Reduction of phenol to benzoate: an electron sink reaction used by a highly enriched anaerobic culture
    Open this publication in new window or tab >>Reduction of phenol to benzoate: an electron sink reaction used by a highly enriched anaerobic culture
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    A non-methanogenic pasteurised enrichment culture fermenting phenolto benzoate, butyrate and acetate was studied, focusing on the effects of adding yeast extract (0.1, 0.2 or I g!l) or glucose (1.5 mM) together with the phenol (5 mM). The results showed that the reductive formation of benzoate from phenol increased when either yeast extract (1 g 1-') or glucose was added to the medium. The culture also transformed phenol at a higher rate when glucose was added as a "co-substrate" than when it was grown on phenol alone. Furthermore, higher growth rates occurred in cultures grown on both substrates rather than on glucose or phenol alone.

    Keyword
    phenol fermentation, electron sink, glucose
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-79144 (URN)
    Available from: 2012-06-29 Created: 2012-06-29 Last updated: 2012-06-29Bibliographically approved
  • 46.
    Skogsdal, Y.
    et al.
    Department of Paediatricedical Centre Hospital, Örebro, Swedens, Örebro M.
    Eriksson, Mats
    Department of Paediatricedical Centre Hospital, Örebro, Swedens, Örebro M.
    Schollin, J.
    Department of Paediatricedical Centre Hospital, Örebro, Swedens, Örebro M.
    Analgesia in newborns given oral glucose1997In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 86, no 2, 217-220 p.Article in journal (Refereed)
    Abstract [en]

    There is evidence that newborn babies feel pain even at the lowest gestational ages when they can survive. Because sweet solutions such as sucrose, given orally, may relieve pain in neonates, we decided to compare the effects of two concentrations of glucose (normally used for intravenous infusions) and of breast milk in a randomized controlled trial in 120 babies requiring heel-prick tests. Glucose solutions and breast milk are readily available in the neonatal department. No other treatment was given. Our results strongly suggest that 1 ml of a 30% glucose solution given orally alleviates mild pain significantly and can be used for this purpose in newborns. Breast milk and 10% glucose did not have a similar effect.

  • 47.
    Laustsen, Christoffer
    et al.
    Aarhus University, Denmark.
    Mose Nielsen, Per
    Aarhus University, Denmark.
    Stokholm Norlinger, Thomas
    Aarhus University, Denmark.
    Qi, Haiyun
    Aarhus University, Denmark.
    Kjaergaard Pedersen, Uffe
    Aarhus University, Denmark.
    Bonde Bertelsen, Lotte
    Aarhus University, Denmark.
    Appel Ostergaard, Jakob
    Aarhus University, Denmark; Danish Diabet Acad, Denmark.
    Flyvbjerg, Allan
    Aarhus University, Denmark.
    Henrik Ardenkjaer-Larsen, Jan
    GE Healthcare, Denmark; Technical University of Denmark, Denmark.
    Palm, Fredrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Uppsala University, Sweden.
    Stodkilde-Jorgensen, Hans
    Aarhus University, Denmark.
    Antioxidant treatment attenuates lactate production in diabetic nephropathy2017In: AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY, ISSN 1931-857X, Vol. 312, no 1, F192-F199 p.Article in journal (Refereed)
    Abstract [en]

    The early progression of diabetic nephropathy is notoriously difficult to detect and quantify before the occurrence of substantial histological damage. Recently, hyperpolarized [1-C-13] pyruvate has demonstrated increased lactate production in the kidney early after the onset of diabetes, implying increased lactate dehydrogenase activity as a consequence of increased nicotinamide adenine dinucleotide substrate availability due to upregulation of the polyol pathway, i.e., pseudohypoxia. In this study, we investigated the role of oxidative stress in mediating these metabolic alterations using state-of-the-art hyperpolarized magnetic resonance (MR) imaging. Ten-week-old female Wistar rats were randomly divided into three groups: healthy controls, untreated diabetic (streptozotocin treatment to induce insulinopenic diabetes), and diabetic, receiving chronic antioxidant treatment with TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl) via the drinking water. Examinations were performed 2, 3, and 4 wk after the induction of diabetes by using a 3T Clinical MR system equipped with a dual tuned C-13/H-1-volume rat coil. The rats received intravenous hyperpolarized [1-C-13] pyruvate and were imaged using a slice-selective C-13-IDEAL spiral sequence. Untreated diabetic rats showed increased renal lactate production compared with that shown by the controls. However, chronic TEMPOL treatment significantly attenuated diabetes-induced lactate production. No significant effects of diabetes or TEMPOL were observed on [C-13] alanine levels, indicating an intact glucose-alanine cycle, or [C-13] bicarbonate, indicating normal flux through the Krebs cycle. In conclusion, this study demonstrates that diabetes-induced pseudohypoxia, as indicated by an increased lactate-to-pyruvate ratio, is significantly attenuated by antioxidant treatment. This demonstrates a pivotal role of oxidative stress in renal metabolic alterations occurring in early diabetes.

  • 48.
    Skogsberg, J.
    et al.
    The Computational Medicine Group, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    Dicker, A.
    Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden.
    Ryden, M.
    Rydén, M., Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden.
    Astrom, G.
    Åström, G., Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden.
    Nilsson, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Computational Biology .
    Bhuiyan, H.
    Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    Vitols, S.
    Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    Mairal, A.
    Inserm, U586, Obesity Research Unit, Toulouse, France.
    Langin, D.
    Inserm, U586, Obesity Research Unit, Toulouse, France.
    Alberts, P.
    Biovitrum AB, Stockholm, Sweden.
    Walum, E.
    Biovitrum AB, Stockholm, Sweden.
    Tegnér, Jesper
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Computational Biology .
    Hamsten, A.
    Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    Arner, P.
    Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden.
    Bjorkegren, J.
    Björkegren, J., The Computational Medicine Group, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    ApoB100-LDL acts as a metabolic signal from liver to peripheral fat causing inhibition of lipolysis in adipocytes2008In: PLoS ONE, ISSN 1932-6203, Vol. 3, no 11Article in journal (Refereed)
    Abstract [en]

    Background: Free fatty acids released from adipose tissue affect the synthesis of apolipoprotein B-containing lipoproteins and glucose metabolism in the liver. Whether there also exists a reciprocal metabolic arm affecting energy metabolism in white adipose tissue is unknown. Methods and Findings: We investigated the effects of apoB-containing lipoproteins on catecholamine-induced lipolysis in adipocytes from subcutaneous fat cells of obese but otherwise healthy men, fat pads from mice with plasma lipoproteins containing high or intermediate levels of apoB100 or no apoB100, primary cultured adipocytes, and 3T3-L1 cells. In subcutaneous fat cells, the rate of lipolysis was inversely related to plasma apoB levels. In human primary adipocytes, LDL inhibited lipolysis in a concentration-dependent fashion. In contrast, VLDL had no effect. Lipolysis was increased in fat pads from mice lacking plasma apoB100, reduced in apoB100-only mice, and intermediate in wild-type mice. Mice lacking apoB100 also had higher oxygen consumption and lipid oxidation. In 3T3-L1 cells, apoB100-containing lipoproteins inhibited lipolysis in a dose-dependent fashion, but lipoproteins containing apoB48 had no effect. ApoB100-LDL mediated inhibition of lipolysis was abolished in fat pads of mice deficient in the LDL receptor (Ldlr-/- Apob100/100). Conclusions: Our results show that the binding of apoB100-LDL to adipocytes via the LDL receptor inhibits intracellular noradrenaline-induced lipolysis in adipocytes. Thus, apoB100-LDL is a novel signaling molecule from the liver to peripheral fat deposits that may be an important link between atherogenic dyslipidemias and facets of the metabolic syndrome. © 2008 Skogsberg et al.

  • 49.
    Shavanova, Kateryna
    et al.
    National University of Life and Environm Science Ukraine, Ukraine.
    Bakakina, Yulia
    National Academic Science Belarus, Byelarus.
    Burkova, Inna
    National University of Life and Environm Science Ukraine, Ukraine.
    Shtepliuk, Ivan
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Viter, Roman
    University of Latvia, Latvia.
    Ubelis, Arnolds
    University of Latvia, Latvia.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Starodub, Nickolaj
    National University of Life and Environm Science Ukraine, Ukraine.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology2016In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, no 2Article, review/survey (Refereed)
    Abstract [en]

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

  • 50.
    D'Orazio, P.
    et al.
    Instrumentation Laboratory, Lexington, MA, United States.
    Burnett, R.W.
    Hartford Hospital, Hartford, CT, United States.
    Fogh-Andersen, N.
    Herlev Hospital, Herlev, Denmark, Department of Clinical Biochemistry, Herlev Hospital, 2730 Herlev, Denmark.
    Jacobs, E.
    Wadsworth Center, Albany, NY, United States.
    Kuwa, K.
    University of Tsukuba, Tsukuba, Japan.
    Kulpmann, W.R.
    Külpmann, W.R., Medizinizche Hochschule Hannover, Hannover, Germany.
    Larsson, Lasse
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry.
    Lewenstam, A.
    Åbo Akademi University, Åbo-Turku, Finland.
    Maas, A.H.J.
    Eurotrol bv, Ede, Netherlands.
    Mager, G.
    Fresenius, Bad Homburg, Germany.
    Naskalski, J.W.
    Jagiellonian University, Krakow, Poland.
    Okorodudu, A.O.
    Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States.
    Approved IFCC recommendation on reporting results for blood glucose2006In: Clinical Chemistry and Laboratory Medicine, ISSN 1434-6621, Vol. 44, no 12, 1486-1490 p.Article in journal (Refereed)
    Abstract [en]

    In current clinical practice, plasma and blood glucose are used interchangeably with a consequent risk of clinical misinterpretation. In human blood, glucose is distributed, like water, between erythrocytes and plasma. The molality of glucose (amount of glucose per unit water mass) is the same throughout the sample, but the concentration is higher in plasma, because the concentration of water and therefore glucose is higher in plasma than in erythrocytes. Different devices for the measurement of glucose may detect and report fundamentally different quantities. Different water concentrations in the calibrator, plasma, and erythrocyte fluid can explain some of the differences. Results for glucose measurements depend on the sample type and on whether the method requires sample dilution or uses biosensors in undiluted samples. If the results are mixed up or used indiscriminately, the differences may exceed the maximum allowable error for glucose determinations for diagnosing and monitoring diabetes mellitus, thus complicating patient treatment. The goal of the International Federation of Clinical Chemistry and Laboratory Medicine, Scientific Division, Working Group on Selective Electrodes and Point of Care Testing (IFCC-SD-WG-SEPOCT) is to reach a global consensus on reporting results. The document recommends reporting the concentration of glucose in plasma (in the unit mmol/L), irrespective of sample type or measurement technique. A constant factor of 1.11 is used to convert concentration in whole blood to the equivalent concentration in plasma. The conversion will provide harmonized results, facilitating the classification and care of patients and leading to fewer therapeutic misjudgments. © 2006 by Walter de Gruyter.

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