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  • 1.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Johansson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Uhlin, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nephrology.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Noninvasive investigation of blood pressure changes using the pulse wave transit time: A novel approach in the monitoring of hemodialysis patients2005In: Journal of Artificial Organs, ISSN 1434-7229, E-ISSN 1619-0904, Vol. 8, no 3, p. 192-197Article in journal (Refereed)
    Abstract [en]

    Severe blood pressure changes are well known in hemodialysis. Detection and prediction of these are important for the well-being of the patient and for optimizing treatment. New noninvasive methods for this purpose are required. The pulse wave transit time technique is an indirect estimation of blood pressure, and our intention is to investigate whether this technique is applicable for hemodialysis treatment. A measurement setup utilizing lower body negative pressure and isometric contraction was used to simulate dialysis-related blood pressure changes in normal test subjects. Systolic blood pressure levels were compared to different pulse wave transit times, including and excluding the cardiac preejection period. Based on the results of these investigations, a pulse wave transit time technique adapted for dialysis treatment was developed and tried out on patients. To determine systolic blood pressure in the normal group, the total pulse wave transit time was found most suitable (including the cardiac preejection period). Correlation coefficients were r = 0.80 ± 0.06 (mean ± SD) overall and r = 0.81 ± 0.16 and r = 0.09 ± 0.62 for the hypotension and hypertension phases, respectively. When applying the adapted technique in dialysis patients, large blood pressure variations could easily be detected when present. Pulse wave transit time is correlated to systolic blood pressure within the acceptable range for a trend-indicating system. The method's applicability for dialysis treatment requires further studies. The results indicate that large sudden pressure drops, like those seen in sudden hypovolemia, can be detected. © The Japanese Society for Artificial Organs 2005.

  • 2.
    Almroth, Gabriel
    et al.
    Linköping University, Department of Medicine and Care, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Lonn, J
    University of Örebro, Sweden .
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Nayeri, Fariba
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Infectious Diseases.
    Brudin, Lars
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Andersson, B
    Sahlgrens University Hospital, Sweden .
    Hahn-Zoric, M
    Sahlgrens University Hospital, Sweden .
    Fibroblast Growth Factor 23, Hepatocyte Growth Factor, Interleukin-6, High-Sensitivity C-Reactive Protein and Soluble Urokinase Plasminogen Activator Receptor. Inflammation Markers in Chronic Haemodialysis Patients?2013In: Scandinavian Journal of Immunology, ISSN 0300-9475, E-ISSN 1365-3083, Vol. 78, no 3, p. 285-290Article in journal (Refereed)
    Abstract [en]

    Sera from 84 haemodialysis (HD) patients and 68 healthy blood donors were analysed with commercially available ELISA techniques for fibroblast growth factor 23 (FGF-23), hepatocyte growth factor (HGF), interleukin-6 (Il-6), high-sensitivity C-reactive protein (hs-CRP) and soluble urokinase plasminogen activator receptor (suPAR), to find a possible correlation of FGF-23 and HGF with the earlier recognized inflammatory markers Il-6 and hs-CRP or suPAR. All patients studied had significantly elevated levels of FGF-23, HGF, hs-CRP and suPAR as compared to the controls. Il-6 and hs-CRP correlated for patients (R=0.6) as well as for patients and controls altogether. Ln (natural logarithm) of HGF correlated weakly with Ln Il-6 and Ln CRP (R 0.28-0.37). Ln FGF-23 correlated only with Ln HGF (r=-0.25) in controls. Ln HGF correlated with ln suPAR (r=0.6) in both patients and controls. Although elevated as compared to controls, we found no correlation of FGF-23 with the recognized inflammatory markers Il-6, hs-CRP, nor HGF or the new marker suPAR in HD patients. Ln HGF correlated with Ln Il-6, Ln CRP and Ln suPAR. Although probably involved in vessel disease, FGF-23 and HGF may play other roles than acting in inflammatory vessel disease in HD patients. Further studies are necessary to evaluate the role of these immunological markers in chronic haemodialysis patients with atherosclerosis.

  • 3.
    Almroth, Gabriel
    et al.
    Linköping University, Department of Medical and Health Sciences, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Lönn, J
    School of Health and Medical Sciences, Örebro, Sweden.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Nayeri, Fariba
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Infectious Diseases.
    Brudin, Lars
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Andersson, B
    Hahn-Zoric, M
    Sahlgrenska University Hospital, Gothenburg, Sweden.
    Tillväxtfaktorer och inflammationsmarkörer vid kronisk njursvikt2013In: Njurmedicinskt vårmöte Jönköping 12-14 maj 2013, 2013Conference paper (Refereed)
  • 4.
    Almroth, Gabriel
    et al.
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Nephrology. Linköping University, Department of Medical and Health Sciences, Division of Drug Research.
    Lönn, Johanna
    Örebro Universitet, Sweden.
    Uhlin, Fredrik
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Nephrology. Linköping University, Department of Medical and Health Sciences, Division of Drug Research.
    Brudin, Lars
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Department of Physiology, County Hospital, Kalmar, Sweden.
    Andersson, Bengt Andersson
    Sahlgrenska University Hospital, Göteborg, Sweden.
    Hahn-Zoric, Mirjana
    Sahlgrenska University Hospital, Göteborg, Sweden.
    Sclerostin, TNF-alpha and Interleukin-18 Correlate and are Together with Klotho Related to Other Growth Factors and Cytokines in Haemodialysis Patients2016In: Scandinavian Journal of Immunology, ISSN 0300-9475, E-ISSN 1365-3083, Vol. 83, no 1, p. 58-63Article in journal (Refereed)
    Abstract [en]

    Patients with chronic renal failure are known to have renal osteodystrophy (bone disease) and increased calcification of vessels. A new marker of bone disease, sclerostin, the two pro-inflammatory cytokines tumour necrosis factor-alpha (TNF-alpha) and interleukin-18 (IL-18), and the fibroblast growth factor-23 (FGF-23) receptor-associated marker Klotho were tested in 84 haemodialysis (HD) patients and in healthy controls. The patients had significantly higher levels of the three former markers than of the controls while Klotho was significantly higher in the controls. Low level, but significant, correlations were observed in the patient group when the levels of these four markers were compared to each other and to those of 5 cytokines and growth factors tested earlier; high-sensitive CRP (hsCRP), interleukin-6 (IL-6), hepatocyte growth factor (HGF), fibroblast growth factor-23 (FGF-23) and soluble urokinase plasminogen activator (suPAR). Ln sclerostin correlated positively to Ln hsTNF-alpha, Ln HGF and Ln suPAR. Ln hsTNF-alpha correlated positively to Ln sclerostin, Ln hsCRP, Ln IL-6, Ln FGF-23, Ln suPAR and Ln IL-18. Ln IL-18 correlated positively to Ln suPAR and Ln TNF-alpha. Ln Klotho correlated negatively to Ln hsCRP but did not correlate to Ln FGF-23. The markers studied here may be involved in the calcification of vessels seen in HD patients due to a combination of inflammation and bone disease. The mechanisms are still not fully known but may be of importance for future therapeutic possibilities in this group of patients.

  • 5. Arund, J
    et al.
    Tanner, Risto
    Tallinn University.
    Lauri, Kai
    Tallinn University.
    Luman, Merike
    Tallinn University.
    Uhlin, 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 Nephrology UHL.
    Fridolin, Ivo
    Contribution of uremic compounds to the total UV absorbance in respect to optical monitoring of dialysis quality2010Conference paper (Other academic)
  • 6. Arund, J
    et al.
    Tanner, Risto
    Tallinn University.
    Lauri, Kai
    Tallinn University.
    Luman, Merike
    Tallinn University.
    Uhlin, 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 Nephrology UHL.
    Fridolin, Ivo
    Relative importance of uremic compounds in total UV absorbance of spent dialysate2010Conference paper (Other academic)
  • 7.
    Arund, Jurgen
    et al.
    Tallinn University of Technology, Estonia.
    Luman, Merike
    North Estonia Medical Centre, Estonia.
    Uhlin, Fredrik
    Region Östergötland, Heart and Medicine Center, Department of Nephrology. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Tallinn University of Technology, Estonia.
    Tanner, Risto
    Tallinn University of Technology, Estonia.
    Fridolin, Ivo
    Tallinn University of Technology, Estonia.
    Is Fluorescence Valid to Monitor Removal of Protein Bound Uremic Solutes in Dialysis?2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 5, article id e0156541Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate the contribution and removal dynamics of the main fluorophores during dialysis by analyzing the spent dialysate samples to prove the hypothesis whether the fluorescence of spent dialysate can be utilized for monitoring removal of any of the protein bound uremic solute. A high performance liquid chromatography system was used to separate and quantify fluorophoric solutes in the spent dialysate sampled at the start and the end of 99 dialysis sessions, including 57 hemodialysis and 42 hemodiafiltration treatments. Fluorescence was acquired at excitation 280 nm and emission 360 nm. The main fluorophores found in samples were identified as indole derivatives: tryptophan, indoxyl glucuronide, indoxyl sulfate, 5-hydroxy-indoleacetic acid, indoleacetyl glutamine, and indoleacetic acid. The highest contribution (35 +/- 11%) was found to arise from indoxyl sulfate. Strong correlation between contribution values at the start and end of dialysis (R-2 = 0.90) indicated to the stable contribution during the course of the dialysis. The reduction ratio of indoxyl sulfate was very close to the decrease of the total fluorescence signal of the spent dialysate (49 +/- 14% vs 51 +/- 13% respectively, P = 0.30, N = 99) and there was strong correlation between these reduction ratio values (R-2 = 0.86). On-line fluorescence measurements were carried out to illustrate the technological possibility for real-time dialysis fluorescence monitoring reflecting the removal of the main fluorophores from blood into spent dialysate. In summary, since a predominant part of the fluorescence signal at excitation 280 nm and emission 360 nm in the spent dialysate originates from protein bound derivatives of indoles, metabolites of tryptophan and indole, the fluorescence signal at this wavelength region has high potential to be utilized for monitoring the removal of slowly dialyzed uremic toxin indoxyl sulfate.

  • 8.
    Arund, Jürgen
    et al.
    Tallinn University of Technology, Estonia.
    Tanner, Risto
    Tallinn University of Technology, Estonia.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Fridolin, Ivo
    Tallinn University of Technology, Estonia.
    Do Only Small Uremic Toxins, Chromophores, Contribute to the Online Dialysis Dose Monitoring by UV Absorbance?2012In: Toxins, ISSN 2072-6651, E-ISSN 2072-6651, Vol. 4, no 10, p. 849-861Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to evaluate the contributions of the main chromophores to the total UV absorbance of the spent dialysate and to assess removal dynamics of these solutes during optical on-line dialysis dose monitoring. High performance chromatography was used to separate and quantify UV-absorbing solutes in the spent dialysate sampled at the start and at the end of dialysis sessions. Chromatograms were monitored at 210, 254 and 280 nm routinely and full absorption spectra were registered between 200 and 400 nm. Nearly 95% of UV absorbance originates from solutes with high removal ratio, such as uric acid. The contributions of different solute groups vary at different wavelengths and there are dynamical changes in contributions during the single dialysis session. However, large standard deviation of the average contribution values within a series of sessions indicates remarkable differences between individual treatments. A noteworthy contribution of Paracetamol and its metabolites to the total UV absorbance was determined at all three wavelengths. Contribution of slowly dialyzed uremic solutes, such as indoxyl sulfate, was negligible.

  • 9.
    Broström, Anders
    et al.
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Department of Medicine and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Ståhlkrantz, A
    n/a.
    Albers, J
    n/a.
    Nyström, Fredrik
    Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL. Linköping University, Department of Medicine and Health Sciences, Internal Medicine . Linköping University, Faculty of Health Sciences.
    Sunnergren, O
    n/a.
    Uhlin, Fredrik
    Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL. Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences.
    Svanborg, Eva
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Department of Clinical and Experimental Medicine, Clinical Neurophysiology . Linköping University, Faculty of Health Sciences.
    Difference in clinical characteristics, self rated sleep and daytime sleepiness between hypertensive patients with or without risk of obstructive sleep apnoea - a pilot study in a primary care setting2008In: ESC - European Society of Cardiology EruoPRevent Congress, 2008Conference paper (Refereed)
  • 10.
    Enberg, Per
    et al.
    Linköping University, Department of Medical and Health Sciences, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Nephrology UHL.
    Fridolin, Ivo
    Tallinn University of Technology, Estonia.
    Holmar, Jana
    Tallinn University of Technology, Estonia.
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Nephrology UHL.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Nephrology UHL.
    Utilization of UV absorbance for estimation of phosphate elimination during hemodiafiltration2012In: Nephron. Clinical practice, ISSN 1660-8151, E-ISSN 2235-3186, Vol. 121, no 1-2, p. c1-c9Article in journal (Refereed)
    Abstract [en]

    Background: Phosphate is an important factor in explaining the high progress of vascular calcification among dialysis patients. Today, phosphate concentration is measured in plasma on a regular basis. The aim of this study was to find out if it is possible to estimate total removed phosphate (TRp) in spent dialysate utilizing UV absorbance during hemodiafiltration. Methods: Eleven patients were monitored online with UV absorbance at 297 nm, three times during one week each (n = 33). Dialysate samples were taken at different times during treatment and from a collection tank to chemically determine phosphate concentrations. Two mathematical models (UVIND and UVGROUP) were tested to estimate TRp with supervision by UV absorbance and compared with TRp measured in the tank (reference). Results: High correlation between UV absorbance and phosphate concentration for each single patient and lower for the whole group together was found. TRp was (mean +/- SD) 30.7 +/- 7.3 mmol for the reference and 30.8 +/- 8.2 and 29.1 +/- 5.2 mmol for UVIND and UVGROUP, respectively (p > 0.05). Conclusion: This study demonstrates a novel possibility to estimate TRp based on linear relationship between online monitoring of UV absorbance and concentration of phosphate in spent dialysate.

  • 11. Fogelberg, Annika
    et al.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Yngman-Uhlin, Pia
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Research & Development Unit in Local Health Care.
    VÄNTAN PÅ EN NJURTRANSPLANTATION - ur ett patientperspektiv2014Conference paper (Other academic)
  • 12.
    Fridolin, Ivo
    et al.
    Tallinn University, Estonia.
    Holmar, Jana
    Tallinn University, Estonia.
    Arund, Jürgen
    Tallinn University, Estonia.
    Tanner, Risto
    Tallinn University, Estonia.
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Optical dialysis dose estimation for B2-microglubulin by fluorescencein the spent dialysate2011Conference paper (Refereed)
  • 13. Fridolin, Ivo
    et al.
    Jerotskaja, Jana
    Tallinn University.
    Lauri, Kai
    Tallinn University.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Luman, Merike
    Tallinn University.
    A New Optical Method for Measuring Creatinine Concentration Removed During Dialysis2010In: XII Mediterranean Conference on Medical and Biological Engineering and Computing 2010 IFMBE Proceedings, 2010, Springer , 2010, p. 379-382Conference paper (Refereed)
    Abstract [en]

    The aim of this study was to compare creatinine (Cr) concentration measurements removed during dialysis by two optical algorithms based on single wavelength and multiwavelength UV-absorbance. Ten uremic patients, three females and seven males, mean age 62.6 ± 18.6 years, on chronic thrice-weekly hemodialysis were included in the study. Double-beam spectrophotometer (Shimatsu UV-2401 PC, Japan) was used for the determination of UV-absorbance in the collected spent dialysate samples. Two optical algorithms were developed to calculate Cr concentration removed during dialysis from measured UVabsorbance: (i) an algorithm utilizing only a single wavelength, revealing Cr concentration Cr_sw; (ii) an algorithm utilizing several wavelengths (multiwavelength algorithm), revealing Cr concentration Cr_mw. The mean value of Cr estimated at the laboratory was 107 ± 46,7 micromol/l, while UV-absorbance as Cr_sw (242 nm) was 107 ± 42.7 micromol/l, and 107 ± 44.7 micromol/l as Cr_mw. The mean concentrations were not significantly different (P = 0.99). The systematic errors, using Cr_lab as a reference, were -2.7% for Cr_sw and -1.7% for Cr_mw, and random errors were 17.3% and 13.6% for Cr_sw and Cr_mw, respectively. The systematic error was not significantly different for two optical algorithms (P = 0.25). The random error decreased significantly (P < 0.05) using Cr_mw algorithm compared to the Cr_sw model. In summary, the creatinine concentration removed during dialysis can be estimated with UV-absorbance technique.

  • 14. Fridolin, Ivo
    et al.
    Jerotskaja, Jana
    Tallinn University.
    Lauri, Kai
    Tallinn University.
    Uhlin, 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 Nephrology UHL.
    Luman, Merike
    Tallinn University.
    Lean Body Mass (LBM) Estimation by UV-Absorbance Measurements in the Spent Dialysate2010Conference paper (Other academic)
  • 15.
    Holmar, J
    et al.
    Tallin University of Technology, Estonia .
    Fridolin, I
    Tallin University of Technology, Estonia .
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Luman, M
    North Estonian Medical Centre, Estonia .
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Can combined assessment of small molecule uremic markers improve prediction of dialysis patients survival?2014Conference paper (Other academic)
  • 16.
    Holmar, Jana
    et al.
    Tallinn University of Technology, Estonia.
    Arund, Jürgen
    Tallinn University of Technology, Estonia.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Tanner, Risto
    Tallinn University of Technology, Estonia.
    Fridolin, Ivo
    Tallinn University of Technology, Estonia.
    New optical method for estimation of protein bound uremic toxins elimination2012Conference paper (Refereed)
    Abstract [en]

    The aim of this study was to investigate the possibility to determine the amount of removed Indoxyl Sulphate (IS) during dialysis session. An optical method using fluorescence spectra was used.

    Eight uremic patients were studied during three dialysis treatments per patient in one week at the Department of Nephrology at Linköping University Hospital. Dialysate samples were taken during each treatment and analyzed at laboratory. IS concentration was estimated using HPLC method, and fluorescence spectra was measured with spectrofluorophotometer. The fluorescence spectral values were transformed into IS concentration using regression model from the total material noted as fluorescence method (F). Removal ratio (RR) was calculated for both. Achieved results were compared regarding mean values and SD and collated with urea reduction ratio (URR) of same dialysis procedures.

    Mean RR value (%) for urea was 74.55±8.11. RR for IS estimated by HPLC was 54.01±8.44 % and by F 58.95±10.94 %. The values were not significantly different (p≤0.05).

    This study indicates, that it is possible to estimate RR of IS using only fluorescence values of the spent dialysate and achieved parameter can be used for describing the elimination of protein bound uremic toxins during the dialysis procedure.

  • 17.
    Holmar, Jana
    et al.
    Tallinn University.
    Arund, Jürgen
    Uhlin, 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 Nephrology UHL.
    Tanner, Risto
    Tallinn University.
    Fridolin, Ivo
    Tallinn University.
    Quantification of indoxyl sulphate in the spent dialysate using fluorescence spectra2011In: IFMBE Proceedings, ISSN 1680-0737, Vol. 34, p. 45-48Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate the possibility to determine the amount of Indoxyl Sulphate (IS) in the spent dialysate using fluorescence spectra. Eight uremic patients from Linköping were studied during their three dialysis treatments in one week at the Department of Dialysis and Nephrology at Linköping University Hospital. Dialysate samples were taken during each treatment and analyzed, IS concentration was estimated using HPLC method, and fluorescence spectra was measured with spectrofluorophotometer. The fluorescence spectral values were transformed into IS concentration using regression model from total material noted as fluorescence method (F). Achieved results were compared regarding mean values and SD. Mean value of IS estimated by HPLC was 1.21±0.77 mg/l and by F 1.22±0.72 mg/l. Concentrations were not significantly different (p≤0,05). This study indicates, that it is possible to estimate the concentration of IS using only fluorescence values of the spent dialysate.

  • 18.
    Holmar, Jana
    et al.
    Tallinn University of Technology, Estonia.
    Fridolin, Ivo
    Tallinn University of Technology, Estonia.
    Uhlin, Fredrik
    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 Nephrology. Tallinn University of Technology, Estonia.
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Luman, Merike
    Tallinn University of Technology, Estonia; North Estonian Medical Centre, Estonia.
    Estimation of dialysis patients survival through combined approach of small molecule uremic markers2014In: Proceedings of the Estonian Academy of Sciences, ISSN 1736-6046, E-ISSN 1736-7530, Vol. 63, no 3, p. 227-233Article in journal (Refereed)
    Abstract [en]

    Survival rate of dialysis patients is still alarmingly low and various factors may have in it an important role. The purpose of this study was to observe the relationship between the survival of dialysis patients and the serum level of urea, creatinine, and uric acid (UA). Serum urea and creatinine concentrations may express patients nutritional status and muscle mass, and high UA value may refer to higher risk for cardiovascular events. The idea of combining the concentrations and removal of urea and UA into a single model for predicting the patients outcome is introduced. The study included 33 hemodialysis patients from Link ping, Sweden and 10 from Tallinn, Estonia. Kaplan-Meier analysis was used for survival analysis. Logistic and Cox regression analysis was applied to create models for predicting patients three-year survival. It was observed that higher serum UA is significantly related to poor survival in dialysis patients (p = 0.026). A reverse effect was observed in case of urea (p = 0.095). The level of creatinine was not related to survival (p = 0.905). The best logistic regression model for predicting patients outcome included both UA and urea based parameters (Chi Square 21.0, p = 0.0001). Survival of dialysis patients seems to be determined by a set of causal factors and combined models may have a predictive relevance. A possibility for automatic online monitoring of small molecule uremic markers is proposed. Since the number of participating patients was small, larger studies including more patients and testing the models in independent validation cohort is the future goal.

  • 19.
    Holmar, Jana
    et al.
    Department of Biomedical Engineering, Technomedicum, Tallinn University.
    Fridolin, Ivo
    1Department of Biomedical Engineering, Technomedicum, Tallinn University.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Lauri, Kai
    1Department of Biomedical Engineering, Technomedicum, Tallinn University.
    Luman, Merike
    1Department of Biomedical Engineering, Technomedicum, Tallinn University.
    Optical method for cardiovascular risk marker uric acid removal assessment during dialysis2012In: Scientific World Journal, ISSN 1537-744X, E-ISSN 1537-744X, Vol. 2012, p. 8-Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to estimate the concentration of uric acid (UA) optically by using the original and processed ultraviolet (UV) absorbance spectra of spent dialysate. Also, the effect of using several wavelengths (multi-wavelength algorithms) for estimation was examined. This paper gives an overview of seven studies carried out in Linköping, Sweden, and Tallinn, Estonia. A total of 60 patients were monitored over their 188 dialysis treatment procedures. Dialysate samples were taken and analysed by means of UA concentration in a chemical laboratory and with a double-beam spectrophotometer. The measured UV absorbance spectra were processed. Three models for the original and three for the first derivate of UV absorbance were created; concentrations of UA from the different methods were finally compared in terms of mean values and SD. The mean concentration (micromol/L) of UA was 49.7 ± 23.0 measured in the chemical laboratory, and 48.9 ± 22.4 calculated with the best estimate among all models. The concentrations were not significantly different (P ≥ 0.17). It was found that using a multi-wavelength and processed signal approach leads to more accurate results, and therefore these approaches should be used in future.

  • 20.
    Holmar, Jana
    et al.
    Tallinn University of Technology, Estonia.
    Fridolin, Ivo
    Tallinn University of Technology, Estonia.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Luman, Merike
    Estonian Medical Centre, Tallinn, Estonia.
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Serum uric acid level and long term survival in dialysis patients2013In: 50th ERA-EDTA Congress, Istanbul, 2013, 2013Conference paper (Other academic)
  • 21.
    Holmar, Jana
    et al.
    Tallinn University of Technology, Estonia .
    Uhlin, Fredrik
    Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology. Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Ferenets, R
    Tallinn University of Technology, Estonia.
    Lauri, K
    Tallinn University of Technology, Estonia.
    Tanner, R
    Tallinn University of Technology; Estonia.
    Arund, J
    Tallinn University of Technology, Estonia.
    Luman, M
    Tallinn University of Technology, Estonia.
    Fridolin, Ivo
    Tallinn University of Technology, Estonia.
    Estimation of removed uremic toxin indoxyl sulphate during hemodialysis by using optical data of the spent dialysate2013In: IEEE Engineering in Medicine and Biology Society Conference Proceedings, IEEE , 2013, p. 6707-6710Conference paper (Refereed)
    Abstract [en]

    The aim of this study was to explore the possibility to determine the amount of total removed Indoxyl Sulphate (TR_IS) during dialysis session, an optical method utilizing absorbance and fluorescence spectral data of the spent dialysate was used. Eight uremic patients from Linköping, Sweden and 10 from Tallinn, Estonia, were studied during dialysis treatments. Dialysate samples were taken during each treatment and analyzed at a laboratory. Fluorescence and absorbance spectra of the spent dialysate were measured with spectrofluorophotometer and spectrophotometer. The spectral values were transformed into IS concentration using multiple linear regression model from the total material noted as optical method (Opt). IS concentration was estimated using high-performance liquid chromatography (HPLC) method as a reference. TR_IS values were calculated. Achieved results were compared regarding mean values and SD and collated with the amount of total removed urea value (TR_Urea) for the same dialysis procedures. Mean TR value ± SD (mg) for urea was 28 947 ± 9 241; TR for IS was 151.4 ± 87.3 estimated by HPLC and 149.4 ± 84.9 estimated by Opt. The TR_IS values were not significantly different (p ≤ 0.05). This study indicates, that it is possible to estimate TR_IS using only spectral values of the spent dialysate and the parameter can be used for quantifying the elimination of protein bound uremic toxins during the dialysis procedure.

  • 22.
    Holmar, Jana
    et al.
    Tallin University of Technology, Tallin, Estonia .
    Uhlin, Fredrik
    Region Östergötland, Heart and Medicine Center, Department of Nephrology. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Region Östergötland, Heart and Medicine Center, Department of Nephrology. Linköping University, Faculty of Medicine and Health Sciences.
    Luman, Merike
    Tallin University of Technology, North Estonian Medical Centre, Tallin, Estonia.
    Jankowski, Joachim
    Aachen University , University Hospital Aachen, Germany .
    Fridolin, Ivo
    Tallin University of Technology, Tallin, Estonia.
    An Optical Method for Serum Calcium and Phosphorus Level Assessment during Hemodialysis2015In: Toxins, ISSN 2072-6651, Vol. 7, no 3, p. 719-727Article in journal (Refereed)
    Abstract [en]

    Survival among hemodialysis patients is disturbingly low, partly because vascular calcification (VC) and cardiovascular disease are highly prevalent. Elevated serum phosphorus (P) and calcium (Ca) levels play an essential role in the formation of VC events. The purpose of the current study was to reveal optical monitoring possibilities of serum P and Ca values during dialysis. Twenty-eight patients from Tallinn (Estonia) and Linköping (Sweden) were included in the study. The serum levels of Ca and P on the basis of optical information, i.e., absorbance and fluorescence of the spent dialysate (optical method) were assessed. Obtained levels were compared in means and SD. The mean serum level of Ca was 2.54 ± 0.21 and 2.53 ± 0.19 mmol/L; P levels varied between 1.08 ± 0.51 and 1.08 ± 0.48 mmol/L, measured in the laboratory and estimated by the optical method respectively. The levels achieved were not significantly different (p = 0.5). The Bland-Altman 95% limits of agreement between the two methods varied from -0.19 to 0.19 for Ca and from -0.37 to 0.37 in the case of P. In conclusion, optical monitoring of the spent dialysate for assessing the serum levels of Ca and P during dialysis seems to be feasible and could offer valuable and continuous information to medical staff.

  • 23.
    Holmar, Jana
    et al.
    1Tallinn University of Technology, Department of Biomedical Engineering, Tallinn, Estonia.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences.
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences.
    Luman, Merike
    North Estonia, Medical Centre, Centre of Nephrology,Tallinn, Estonia.
    Jankowski, Joachim
    RWTH Aachen University, Institute for Molecular Cardiovascular.
    Fridolin, Ivo
    1Tallinn University of Technology, Department of Biomedical Engineering, Tallinn, Estonia.
    Optical assesment of calcification markers during hemodialysis2015Conference paper (Other academic)
  • 24.
    Jerotskaja, J
    et al.
    n/a.
    Uhlin, F
    Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL. Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences.
    Fridolin, I
    n/a.
    A Multicenter Study of Removed Uric Acid Estimated by Ultra Violet Absorbance in the Spent Dialysate2008In: NBC - Nordic-Baltic Conference on Biomedical Engineering and Medical Physics, Springer Berlin Heidelberg , 2008, p. 252-256Conference paper (Refereed)
    Abstract [en]

    The aim of this study was to investigate the relation between removed uric acid (UA) and measured ultra violet (UV) absorbance of the spent dialysate during dialysis.

    Ten uremic patients from Tallinn and ten from Linköping, during 30+40 haemodialysis treatments, were followed at the Departments of Dialysis and Nephrology at North-Estonian Medical Centre and at Linköping University Hospital. The dialysate samples were taken and analyzed by means of UA concentration at the chemical laboratory and with a doublebeam spectrophotometer. UV absorbance at the wavelength of 297 nm was transformed into UA concentration in the spent dialysate using the regression model from the total material, noted as general model.

    Mean concentration of UA was 53,4 ± 22,7 micromol/l measured at the chemical laboratory, and 53,4 ± 21,4 micromol/l determined by UV-absorbance. The results were not significantly different (p < 0.05). The concentrations found did differ less than 10%.

    Our study indicates that the removed UA can be reliably estimated in different dialysis centres by the UV technique.

  • 25.
    Jerotskaja, J
    et al.
    n/a.
    Uhlin, Fredrik
    Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL. Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences.
    Lauri, Kai
    n/a.
    Tanner, Risto
    n/a.
    Luman, Merike
    n/a.
    Fridolin, Ivo
    n/a.
    A multicentre study of an enhanced optical method for measuring concentration of uric acid removed during dialysis2009In: EMBC`09, The Engineering in Medicine and Biology Conference, 2009Conference paper (Refereed)
  • 26.
    Jerotskaja, Jana
    et al.
    n/a.
    Uhlin, Fredrik
    Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL. Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Internal Medicine .
    Fridolin, Ivo
    n/a.
    Fernström, Anders
    Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL. Linköping University, Department of Medicine and Health Sciences. Linköping University, Faculty of Health Sciences.
    Luman, Merike
    n/a.
    Multicenter optical monitoring of removed uremic toxin and cardiovascular risk marker uric acid during dialysis2009In: World Congress of Nephrology, 2009Conference paper (Other (popular science, discussion, etc.))
  • 27.
    Jerotskaja, Jana
    et al.
    Tallinn University Technology.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL. Östergötlands Läns Landsting, Heart and Medicine Center.
    Fridolin, Ivo
    Tallinn University Technology.
    Lauri, Kai
    Tallinn University Technology.
    Luman, Merike
    North Estonia Medical Centre.
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Optical Online Monitoring of Uric Acid Removal during Dialysis2010In: BLOOD PURIFICATION, ISSN 0253-5068, Vol. 29, no 1, p. 69-74Article in journal (Refereed)
    Abstract [en]

    This study estimates the total removal of uric acid (TRUA) by online UV absorbance measurements in the spent dialysate in two different dialysis centers in Estonia and Sweden. Sixteen dialysis patients were included. All dialysate was collected that gave the reference for TRUA. Two regression models were investigated: one for each patient (UV1) and one for the entire material (UV2). TRUA from the three methods was in the same order but showed a statistically significant difference when the UV2 model was built on data from both centers together. TRUA, (n = 56) was (mean +/- SD, mu mol): 5,854 +/- 1,377 for reference, 6,117 +/- 1,795 for UV1 and 5,762 +/- 1,591 for UV2. Six patients were monitored 1 year after the first study session, using the same models as the previous year, still having a nonsignificant difference. The results show the possibility of estimating TRUA by using UV absorbance. The method appeared to be reliable also in long-term patient monitoring.

  • 28.
    Jerotskaja, Jana
    et al.
    Department of Biomedical Engineering, Technomedicum, Tallinn University of Technology, Tallinn, Estonia.
    Uhlin, Fredrik
    Linköping University, Department of Medicine and Care, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    Lauri, Kai
    Department of Biomedical Engineering, Technomedicum, Tallinn University of Technology, Tallinn, Estonia.
    Tanner, Risto
    Department of Biomedical Engineering, Technomedicum, Tallinn University of Technology, Tallinn, Estonia.
    Luman, Merike
    Department of Dialysis and Nephrology, North-Estonian Regional Hospital, Tallinn, Estonia.
    Fridolin, Ivo
    Department of Biomedical Engineering, Technomedicum, Tallinn University of Technology, Tallinn, Estonia.
    A multicentre study of an enhanced optical method for measuring concentration of uric acid removed during dialysis.2009In: Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009. EMBC 2009, 2009, no 1, p. 1477-1480Conference paper (Refereed)
    Abstract [en]

    The aim of this study was to compare concentration measurements of uric acid (UA) removed during dialysis by two algorithms based on UV-absorbance and the 1st derivate of UV absorbance. Ten uremic patients from Tallinn and ten from Linköping, during 30+40 haemodialysis treatments, were followed at the Departments of Dialysis and Nephrology at North-Estonian Medical Centre and at Linköping University Hospital. The dialysate samples were taken and analyzed by means of UA concentration at the chemical laboratory and with a double-beam spectrophotometer. UV absorbance and derivate of UV absorbance was transformed into UA concentration in the spent dialysate using the regression models from the calibration set of material, noted as UV-absorbance (UV_A) and the 1st derivate of UV absorbance (UV_D) method. These models were tested on validation set of material and concentrations of UA from the two methods were compared regarding mean values and SD. Mean concentration of UA were 52.7 +/- 25.0 micromol/l measured at the chemical laboratory (UA_Lab), 54.9 +/- 23.8 micromol/l determined by UV_A and 52.9 +/- 23.0 micromol/l determined by UV_D. The results of mean concentrations were not significantly different (p >/= 0.54). The systematic errors were -7.8 % and -3.3% and random errors were 15.8 % and 10.4 % using UV_A and UV_D respectively. The systematic and random errors were significantly different (p < 0.05) indicating that the new algorithm enables more accurate UA estimation.

  • 29.
    Jerotskaja, Jana
    et al.
    Tallinn University.
    Uhlin, 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 Nephrology UHL.
    Lauri, Kai
    Tallinn University.
    Tanner, Risto
    Tallinn University.
    Luman, Merike
    Tallinn University.
    Fridolin, Ivo
    Concentration of uric acid removed during dialysis. Estimated by multi wavelength and processed ultra violet absorbance spectra2010In: Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE, ISSN: 1557-170X, IEEE , 2010, Vol. 2010, p. 5791-5794Conference paper (Refereed)
    Abstract [en]

    The aim of this study was to estimate the concentration of uric acid (UA) optically by using original and processed ultra violet (UV) absorbance spectra's of the spent dialysate. Also the effect of using several wavelengths for estimation was examined. Ten uremic patients from Tallinn and ten from Linkoping, during 30+40 hemodialysis treatments, were followed at the Departments of Dialysis and Nephrology at North-Estonian Medical Centre and at Linkoping University Hospital. The dialysate samples were taken and analyzed by means of UA concentration at the chemical laboratory and with a doublebeam spectrophotometer. From the calibration set of material three models for original and three for Is' derivate of UV absorbance were created. These models were tested on validation set of material and concentrations of UA from the different methods were compared regarding mean values and SD. It was found that the concentration of UA can be estimated by UV absorbance method whereby using processed UV absorbance spectra and absorbance values from several wavelengths gives better and more accurate results.

  • 30.
    Jerotskaja, Jana
    et al.
    Tallinn University.
    Uhlin, 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 Nephrology UHL.
    Luman, Merike
    Tallinn University.
    Lauri, Kai
    Tallinn University.
    Fridolin, Ivo
    Improved optical method for measuring concentration of uric acid removed during dialysis2010In: XII Mediterranean Conference on Medical and Biological Engineering and Computing 2010 IFMBE Proceedings, 2010, Springer , 2010, p. 124-127Conference paper (Refereed)
    Abstract [en]

    The aim of this study was to compare concentration measurements of uric acid (UA) removed during dialysis. Algorithms based on ultraviolet (UV) absorbance and 1st derivate of UV-absorbance whereby single and multi-wavelength was used. Ten uremic patients from Tallinn and ten from Linköping, during 30+40 haemodialysis treatments, were followed at the Departments of Dialysis and Nephrology at North-Estonian Medical Centre and at Linköping University Hospital. The dialysate samples were taken and analyzed by means of UA concentration at the chemical laboratory and with a double-beam spectrophotometer. UV absorbance and derivate of UV absorbance value on single or multi wavelength was transformed into UA concentration in the spent dialysate using the regression models from the total material, noted as UV-absorbance (UV_A _single and UV_A_multi) and the 1st derivate of UV absorbance (UV_D_single and UV_D_multi) method. Concentrations of UA from the different methods were finally compared regarding mean values and SD. Mean concentration of UA were 52,40 ± 23,1 micromol/l measured at the chemical laboratory (UA_Lab), 52,39 ± 21,8 micromol/l determined by UV_A_single, 52,42 ± 22,4 micromol/ l determined by UV_A_multi and 52,4 ± 22,2 micromol/l determined by UV_D_single and 52,4 ± 22,9 micromol/l determined by UV_D_multi. The results of mean concentrations were not significantly different (p ≥ 0,95). The systematic errors were -0,7- -2,6% and random errors were 8 - 16 % using different methods. The systematic and random errors were significantly different (p < 0.05) between different algorithms indicating that the algorithm that uses multi wavelengths from derivative spectra enables more accurate UA estimation. Our study indicates that the removed UA can be reliably and more accurately estimated by the UV_D_multi technique.

  • 31.
    Jerotskaja, Jana
    et al.
    Tallinn University.
    Uhlin, 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 Nephrology UHL.
    Luman, Merike
    Tallinn University.
    Lauri, Kai
    Tallinn University.
    Tanner, Risto
    Tallinn University.
    Fridolin, Ivo
    Determination of concentration of uric acid removed during dialysis by ultraviolet absorbance:  A multi wavelength and processed spectra approach2010Conference paper (Other academic)
  • 32.
    Jia, Ting
    et al.
    Karolinska Institute, Sweden .
    Rashid Qureshi, Abdul
    Karolinska Institute, Sweden .
    Brandenburg, Vincent
    Aachen University Hospital, Germany .
    Ketteler, Markus
    Klinikum Coburg, Germany .
    Barany, Peter
    Karolinska Institute, Sweden .
    Heimburger, Olof
    Karolinska Institute, Sweden .
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Magnusson, Per
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Lindholm, Bengt
    Karolinska Institute, Sweden .
    Stenvinkel, Peter
    Karolinska Institute, Sweden .
    Larsson, Tobias E.
    Karolinska Institute, Sweden .
    Determinants of Fibroblast Growth Factor-23 and Parathyroid Hormone Variability in Dialysis Patients2013In: American Journal of Nephrology, ISSN 0250-8095, E-ISSN 1421-9670, Vol. 37, no 5, p. 462-471Article in journal (Refereed)
    Abstract [en]

    Background/Aims: Treatment strategies for abnormal mineral metabolism in chronic kidney disease are largely based on achieving target ranges of biomarkers that vary considerably over time, yet determinants of their variability are poorly defined. Methods: Observational study including 162 patients of three dialysis cohorts (peritoneal dialysis, n = 78; hemodialysis, n = 49; hemodiafiltration, n = 35). Clinical and biochemical determinants of parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF23) variability were analyzed in the peritoneal dialysis cohort. All cohorts were used for comparison of PTH and FGF23 intra-subject variability (intra-class correlation), and their intra-subject variability in different modes of dialysis was explored. Results: High PTH variability was independently associated with lower 25-hydroxyvitamin D concentration and factors of lipid and glucose metabolism, whereas high FGF23 variability was mainly associated with lower baseline serum phosphorous. These results were consistent in multivariate and sensitivity analyses. The intra-subject variability of FGF23 was lower than for PTH irrespective of dialysis mode. Conclusions: Baseline vitamin D status and serum phosphorous are independent determinants of the longitudinal variation in PTH and FGF23, respectively. The clinical utility of FGF23 measurement remains unknown, yet it appears favorable based on its greater temporal stability than PTH in dialysis patients.

  • 33. Lindley, EJ
    et al.
    De Vos, JY
    Morgan, I
    Murcott, G
    Noenich, N
    Polaschegg, H
    Johnson, A
    Daugirdas, J
    Wupper, A
    Ward, R
    Gorke, A
    Fettouhi, M
    Milo, E
    Sramek, J
    Nilsson, EL
    Belot, B
    Luman, M
    Walker, D
    Gerrish, M
    Harrington, M
    Francis, V
    Iwaasa, K
    Girak, M
    Eleftheroundi, M
    Simard, JC
    Fridolin, I
    Uhlin, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nephrology.
    On line UV-absorbance measurements. Summary of the EDTNA/ERCA journal club discussion. Summer 2006.2007In: EDTNA-ERCA Journal, ISSN 1019-083X, Vol. 33, p. 41-48Article in journal (Refereed)
  • 34.
    Lindström, Stefan B
    et al.
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Nephrology. Department of Biomedical Engineering, Technomedicum, Tallinn University of Technology, Tallinn, Estonia.
    Bjarnegård, Niclas
    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 Clinical Physiology in Linköping.
    Gylling, Micael
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Nephrology.
    Nilsson, Kamilla
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Svensson, Christina
    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 Clinical Physiology in Linköping.
    Yngman-Uhlin, Pia
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in West Östergötland, Research & Development Unit in Local Health Care.
    Länne, Toste
    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 Thoracic and Vascular Surgery.
    Computer-Aided Evaluation of Blood Vessel Geometry From Acoustic Images2018In: Journal of ultrasound in medicine, ISSN 0278-4297, E-ISSN 1550-9613, Vol. 37, no 4, p. 1025-1031Article in journal (Refereed)
    Abstract [en]

    A method for computer-aided assessment of blood vessel geometries based on shape-fitting algorithms from metric vision was evaluated. Acoustic images of cross sections of the radial artery and cephalic vein were acquired, and medical practitioners used a computer application to measure the wall thickness and nominal diameter of these blood vessels with a caliper method and the shape-fitting method. The methods performed equally well for wall thickness measurements. The shape-fitting method was preferable for measuring the diameter, since it reduced systematic errors by up to 63% in the case of the cephalic vein because of its eccentricity.

  • 35.
    Lönn, Johanna
    et al.
    PEAS Institut AB, Linköping, Sweden.
    Shahzad, Faisal
    PEAS Institut AB, Linköping, Sweden.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Bengtsson, Torbjörn
    Örebro University, Sweden.
    Almroth, Gabriel
    Linköping University, Department of Medical and Health Sciences, Nephrology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Nayeri, Fariba
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Infectious Diseases.
    High concentration but low biological activity of hepatocyte growth factor in patients with chronic renal failure2012In: Advances in Bioscience and Biotechnology, ISSN 2156-8456, E-ISSN 2156-8502, Vol. 3, no 4, p. 516-523Article in journal (Refereed)
    Abstract [en]

    Hepatocyte growth factor (HGF) is a renotropic, an- tifibrotic and regenerative factor with cytoprotective effects that is produced by mesenchymal cells and shows high affinity to components of extra cellular matrix, such as heparan sulphate proteoglycan (HS- PG), in healthy. Patients with chronic renal failure (CRF) suffer from a chronic inflammatory disorder. In order to assess the underlying mechanisms for de- velopment of CRF we aimed to assess the amounts and affinity of HGF in this patient group. ELISA, western blot and surface plasmon resonance (SPR) were used to study HGF in blood samples, as well as in isolated neutrophils, in CRF patients compared to healthy controls. Patients with CRF showed higher HGF levels in serum (P < 0.0001), but decreased af- finity to HSPG (P < 0.0001). Addition of protease in-hibitors decreased the difference between patients with CRF compared to healthy individuals. HGF with potent regenerative function during injury lacks af-finity to HSPG in patients with CRF that may depend on production of proteases from activated immune cells. This information might be used to highlight un-derlying mechanisms for chronicity and leading to new strategies for treatment of chronic injuries.

     

     

  • 36.
    Metry, G.
    et al.
    Department of Nephrology, University Hospital of Linköping, Linköping, Sweden.
    Uhlin, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Internal Medicine . Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL.
    Almroth, Gabriel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nephrology. Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL.
    Swedish experience of the Dialock2007In: Scandinavian Journal of Urology and Nephrology, ISSN 0036-5599, E-ISSN 1651-2065, Vol. 41, no 3, p. 249-253Article in journal (Refereed)
    Abstract [en]

    Objective. To study the patency and complications associated with the Dialock, an access device for haemodialysis. Material and methods. The records of seven Swedish patients who were treated with the Dialock access device between 2000 and 2004 were studied retrospectively. Results. A total of 10 Dialock devices were used in seven patients. The mean period of patency was 16.3±13.8 months. Major complications observed were bleeding in the dose pocket in three patients and infection in four. Three patients experienced no complications. The 1-year patency was similar to that of a newly created arteriovenous fistula used in our unit. Conclusions. In spite of the associated complications, the Dialock is an acceptable access device for haemodialysis patients with vascular access problems. Although the Dialock is no longer available on the market, similar access devices may be of importance in the future. © 2007 Taylor & Francis.

  • 37.
    Osman, Abdimajid
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Frånlund, Ebba
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Fernström, Anders
    Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology. Linköping University, Department of Medical and Health Sciences, Nephrology. Linköping University, Faculty of Health Sciences.
    Magnusson, Per
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Exon resequencing of the gene encoding UCMA/GRP reveals a common carboxy-terminal 138Thr > Ser Polymorphism2013In: Clinical Laboratory, ISSN 1433-6510, Vol. 59, no 11-12, p. 1397-1401Article in journal (Refereed)
    Abstract [en]

    Background: The upper zone of growth plate and cartilage matrix-associated protein (UCMA), also called Gla-rich protein (GRP), is a novel protein found at sites af-fected by pathological calcifications.Methods: We performed a full exon resequencing on DNA samples from 17 chronic kid-ney disease (CKD) patients (stage 5) and compared the results with 121 healthy con-trols in a Swedish population.Results: A novel non-synonymous single nucleotide polymorphism (SNP) causing a car-boxy-terminal amino acid exchange was found. This SNP involves an alteration of the last ACC codon for threonine in exon 5 (adjacent to the stop codon) to an AGC ser-ine codon (138Thr > Ser). Six controls and two CKD patients were heterozygous for the 138Thr > Ser polymorphism. Both patients had histories of vascular calcifica-tion; however, it is uncertain whether this SNP has any significance for the func-tional domains of the UCMA protein. In addition, a heterozygous transversion muta-tion was found in a patient at SNP rs4750328 (A/G) in intron 2, involving an ex-change of the ancestral A allele to a T base.Conclusions: The 138Thr > Ser polymorphism seems to be the only non-synonymous SNP found in the UCMA gene in a Swedish population.

  • 38.
    Tomson, R
    et al.
    Tallinn University of Technology, Estonia .
    Fridolin, Ivo
    Tallinn University of Technology, Estonia .
    Uhlin, 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 Nephrology UHL.
    Holmar, Jana
    Tallinn University of Technology, Estonia .
    Lauri, K.
    Tallinn University of Technology, Estonia .
    Luman, M.
    Estonian Medical Centre, Tallinn, Estonia.
    Development of the model for the optical monitoring of urea in spent dialysate2012In: Electronics Conference (BEC), 2012, 2012, p. 179-182Conference paper (Refereed)
    Abstract [en]

    The aim of the study was to develop a mathematical model suitable for the estimation of urea concentration removed during dialysis through UV-absorbance. 29 haemodialysis patients on chronic three-times-a-week haemodialysis were studied in 6 separate studies. Double-beam spectrophotometer was used for the determination of UV-absorbance in the collected spent dialysate samples. A single wavelength (SW) and a multi-wavelength (MW) model were developed using stepwise regression utilizing urea values from the laboratory as the dependent parameter. For SW model R2 was 0.656 (calibration set) and 0.729 (validation set), for MW model R2 was 0.696 and 0.764, respectively. In summary, the urea concentration removed during dialysis can be estimated with UV-absorbance technique.

  • 39.
    Tomson, R
    et al.
    Tallinn University.
    Fridolin, Ivo
    Uhlin, 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 Nephrology UHL.
    Jerotskaja, Jana
    Tallinn University.
    Lauri, Kai
    Tallinn University.
    Luman, Merike
    Tallinn University.
    Development of the Model for the Optical Multiwavelength Monitoring of Creatinine in the Spent Dialysate2010In: Proceedings of the 12th Biennial Baltic Electronics Conference: 12th Biennial Baltic Electronics Conference, Tallinn, Estonia, October 4 - 6, 2010, ISSN: 1736-3705, 2010, p. 261-264Conference paper (Refereed)
    Abstract [en]

    The aim of the study was to develop a statistical model suitable for the estimation of creatinine concentration removed during dialysis through UV-absorbance. Ten uremic patients, three females and seven males, mean age 62.6 ± 18.6 years, on chronic thrice-weekly hemodialysis were included in the study. Double-beam spectrophotometer (Shimatsu UV-2401 PC, Japan) was used for the determination of UV-absorbance in the collected spent dialysate samples. Due to differences in independent variables included two multiwavelength models were developed using stepwise regression. The coefficient of determination, R2 was 0.8709 for the first and 0.8756 for the second model. The standard errors were 15.86 micromol/l and 16.01 micromol/l, respectively. In summary, the creatinine concentration removed during dialysis can be estimated with UV-absorbance technique.

  • 40.
    Tomson, Ruth
    et al.
    Tallinn University of Technology, Estonia.
    Fridolin, Ivo
    Tallinn University of Technology, Estonia.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Holmar, Jana
    Tallinn University of Technology, Estonia.
    Lauri, Kai
    Tallinn University of Technology, Estonia.
    Luman, Merike
    North Estonia Medical Center, Tallinn, Estonia.
    Optical measurement of creatinine in spent dialysate2013In: Clinical Nephrology, ISSN 0301-0430, Vol. 79, no 2, p. 107-117Article in journal (Refereed)
    Abstract [en]

    Aim: The aim of the study was to develop an optical method for the estimation of creatinine (Cr) removal during dialysis using UV-absorbance. Material and methods: 29 hemodialysis patients on chronic 3-times-a-week hemodialysis were studied in 6 separate studies. Double-beam pectrophotometer was used for the determination of UV-absorbance in the collected spent dialysate samples. A single wavelength (SW) and a multi-wavelength (MW) model were developed using stepwise regression utilizing Cr values from the laboratory as the dependent parameter. The reduction ratio (RR) and total removed Cr (TRCr) were estimated. Results: For blood-Cr RRb (mean ± SD) was 60.9 ± 5.0% (calibration set) and 58.1 ± 6.0% (validation set), for SW UVabsorbance RR_SW was 61.5 ± 5.9% and 57.3 ± 6.0%, and for MW UV-absorbance RR_MW was 65.8 ± 5.8% and 61.7 ± 6.4% respectively. RR_SW and RRb were not statistically different. RR_MW was higher compared to RRb (p < 0.05). TRCr_lab was 13.8 ± 3.8 mmol, TRCr_SW 14.5 ± 2.5 mmol and TRCr_MW 13.8 ± 2.6 mmol, being not statistically different. Conclusion: In summary, creatinine removal during dialysis can be estimated as reduction ratio and total removed creatinine with the UV-absorbance technique.

  • 41.
    Tomson, Ruth
    et al.
    Tallinn University of Technology, Estonia .
    Uhlin, Fredrik
    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 Nephrology. Tallinn University of Technology, Estonia .
    Fridolin, Ivo
    Tallinn University of Technology, Estonia .
    Urea rebound assessment based on UV-absorbance in spent dialysate2014In: ASAIO journal (1992), ISSN 1058-2916, E-ISSN 1538-943X, Vol. 60, no 4, p. 459-465Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to examine the possibility of post-dialysis urea rebound assessment using UV-absorbance measurements in spent dialysate. Twenty-six patients on chronic three-times-a-week hemodialysis (HD) were studied in two separate studies. Double-beam spectrophotometer was used for the determination of UV absorbance in the collected spent dialysate samples. Also, on-line UV absorbance was monitored. The equilibrium concentration (C-eq) of urea at the end of the rebound phase was calculated based on urea concentration in blood and dialysate and UV absorbance in spent dialysate. Based on C-eq, urea rebound was expressed relative to urea concentration at the end of HD (R-1) and relative to the decrease in urea concentration during HD (R-2). Estimates based on UV-absorbance values in spent dialysate (R-1_a, R-2_a) slightly over assess postdialysis rebound compared with results based on the blood sample drawn 30 min after HD (R-1_30post, R-2_30post), but R-1_a and R-2_a presented greater consistency and accuracy compared with the estimates based on the intradialytic blood sample (R-1_b, R-2_b). In summary, the results show that it is possible to assess postdialysis urea rebound in blood based on UV-absorbance measurements in spent dialysate.

  • 42.
    Tomson, Ruth
    et al.
    Tallinn University of Technology, Estonia.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    Holmar, Jana
    Tallinn University of Technology, Estonia.
    Lauri, Kai
    Tallinn University of Technology, Estonia.
    Luman, Merike
    North Estonia Medical Centre, Tallinn, Estonia.
    Fridolin, Ivo
    Tallinn University of Technology, Estonia.
    Development of a method for optical monitoring of creatinine in the spent dialysate2011In: Estonian Journal of Engineering, ISSN 1736-6038, Vol. 17, no 2, p. 140-150Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to develop a method suitable for the estimation of the amount of creatinine, removed during dialysis through UV-absorbance. Sixteen uremic patients, seven females and nine males, on chronic thrice-weekly hemodialysis were included in the study. Double-beam spectrophotometer was used for the determination of UV-absorbance in the collected spent dialysate samples. Due to differences in independent variables, two multi-wavelength models (m1 and m2) were developed using stepwise regression, utilizing creatinine values from the laboratory as the dependent parameter. The coefficient of determination, R2 was 0.8690 for the first and 0.9103 for the second model. The systematic error, estimated as BIAS, was zero for both models compared to the creatinine values from the laboratory. The standard errors were 10.06 µmol/l and 15.24 µmol/l for m1 and m2, respectively. The average reduction ratio (RR) from creatinine blood values was 59.8 ± 5.4% (N = 50), average RR from m1 was 63.7 ± 7.3% (N = 50) and average RR from m2 was 64.8 ± 6.4% (N = 48). In summary, the amount of creatinine removed as well as the reduction ratio of creatinine during dialysis can be estimated with UV-absorbance technique.

  • 43.
    Uhlin, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nephrology.
    Avhandling visar att dialyseffekten kan mätas on-line med UV-ljus.2007In: Nefromedia, ISSN 1652-2710, Vol. 2, no 5Article in journal (Other academic)
    Abstract [en]

      

  • 44.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Nephrology. Linköping University, Faculty of Medicine and Health Sciences.
    Fler patienter fick D-vitaminbrist efter övergång till HDF.2015In: Dialäsen, ISSN 1104-4616, Vol. 4, p. 19-20Article in journal (Other academic)
  • 45.
    Uhlin, Fredrik
    Linköping University, Department of Medicine and Health Sciences, Internal Medicine . Linköping University, Faculty of Health Sciences.
    Haemodialysis Treatment Monitored On-line by Ultra Violet Absorbance2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes and evaluates an optical method utilizing ultra violet (UV) absorbance for on-line monitoring of haemodialysis treatment. Increased efficiency of haemodialysis treatment is considered to correlate to decreased morbidity and mortality when urea clearance (Kt/V) is elevated. However, further improvements have not been achieved at a higher Kt/V. The mortally rate in the haemodialysis population is still high (27% in Sweden).

    Urea as the clinical marker is under discussion, partly due to urea being non-toxic, but also that the uraemic syndrom is the result of a cumulative retention of innumerable involved compounds.

    On-line monitoring systems based on urea determination for improved dialysis efficiency have been suggested and developed in different settings over the last two decades, but have not achieved worldwide utilisation as routine clinical equipment. This thesis demonstrates that the UV-technique utilising 280, 285 and 297 nm is capable of estimating dialysis efficiency in therms of Kt/V, nutritional status in terms of protein catabolic rate (PCR), with the same characteristics as existing methods. One novel finding using UV-absorbance with high sampling rates is the on-line visualisation of the clearance process for following variations in clearance caused by clinical events and disturbances as well as during and after adjustments. The fact that the UV-absorbance technique does not measure urea directly but has high correlation to several other both UV-absorbing and not-absorbing solutes makes it suitable to reflect a more overall solute retention process. Finally, a new efficiency parameter based on the calculation of the area under UV- curve (clearance curve), is suggested to reflect the total removal of some solutes.

    In summary the UV-technique has the potential to be an additional tool to evaluate improvements of dialysis efficiency, which may result in decreased morbidity, longer life span and enhanced quality of life for the haemodialysis patients.

    List of papers
    1. Estimation of delivered dialysis dose by on-line monitoring of the ultraviolet absorbance in the spent dialysate
    Open this publication in new window or tab >>Estimation of delivered dialysis dose by on-line monitoring of the ultraviolet absorbance in the spent dialysate
    2003 (English)In: American Journal of Kidney Diseases, ISSN 0272-6386, E-ISSN 1523-6838, Vol. 41, no 5, p. 1026-1036Article in journal (Refereed) Published
    Abstract [en]

    Background:

    Several methods are available to determine Kt/V, from predialysis and postdialysis blood samples to using on-line dialysate urea monitors or to ionic dialysance using a conductivity method. The aim of this study is to compare Kt/V calculated from the slope of the logarithmic on-line ultraviolet (UV) absorbance measurements, blood urea Kt/V, dialysate urea Kt/V, and Kt/V from the Urea Monitor 1000 (UM; Baxter Healthcare Corp, Deerfield, IL).

    Methods:

    Thirteen uremic patients on chronic thrice-weekly hemodialysis therapy were included in the study. The method uses absorption of UV radiation by means of a spectrophotometric set-up. Measurements were performed on-line with the spectrophotometer connected to the fluid outlet of the dialysis machine; all spent dialysate passed through a specially designed cuvette for optical single-wavelength measurements. UV absorbance measurements were compared with those calculated using blood urea and dialysate urea, and, in a subset of treatments, the UM.

    Results:

    Equilibrated Kt/V (eKt/V) obtained with UV absorbance (eKt/Va) was 1.19 ± 0.23; blood urea (eKt/Vb), 1.30 ± 0.20, and dialysate urea (eKt/Vd), 1.26 ± 0.21, and Kt/V in a subset measured by the UM (UM Kt/V) was 1.24 ± 0.18. The difference between eKt/Vb and eKt/Va was 0.10 ± 0.11, showing a variation similar to the difference between eKt/Vb and eKt/Vd (0.03 ± 0.10) and in a subset between eKt/Vb and UM Kt/V (−0.02 ± 0.11).

    Conclusion:

    The study suggests that urea Kt/V can be estimated by on-line measurement of UV absorption in the spent dialysate.

    Keywords
    Hemodialysis (HD), dialysis monitoring, dialysis dose, spectrophotometry, absorption, ultraviolet (UV), solute removal, spent dialysate, dialysis adequacy, dialysis efficiency, urea, Kt/V
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14191 (URN)10.1016/S0272-6386(03)00200-2 (DOI)
    Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2017-12-13
    2. Estimating total urea removal and protein catabolic rate by monitoring UV absorbance in spent dialysate
    Open this publication in new window or tab >>Estimating total urea removal and protein catabolic rate by monitoring UV absorbance in spent dialysate
    2005 (English)In: Nephrology Dialysis Transplantation, ISSN 0931-0509, Vol. 20, no 11, p. 2458-2464Article in journal (Refereed) Published
    Abstract [en]

    Background. Dialysate-based, on-line measurements of Kt/V and protein catabolic rate (PCR) in dialysis patients have been considered more accurate compared with measurements on the blood side during dialysis. The primary aim of this study was to compare total removed urea (TRU) and PCR, normalized to body weight (nPCRw), obtained by three dialysate-based methods: (i) on-line ultraviolet (UV) absorbance of the spent dialysate; (ii) total dialysate collection (TDC), as reference method; and (iii) Urea Monitor 1000 (UM) from Baxter Healthcare Corp.

    Methods. We studied 10 uraemic patients on chronic, thrice-weekly haemodialysis. We made absorption measurements (UV radiation) on-line with a spectrophotometer connected to the fluid outlet of the dialysis machine, with all spent dialysate passing through an optical cuvette for single-wavelength measurements. UV absorbance measurements were compared with TDC and the UM.

    Results. nPCRw obtained with UV absorbance was 0.82±0.17, that from TDC 0.81±0.18, and that measured by UM 0.87±0.18, which was significantly higher than the results of the other methods. The difference between nPCRw calculated by TDC and by UM was –0.05±0.06, showing a slightly lower SD than the difference between nPCRw by TDC and UV absorbance, –0.01±0.07.

    Conclusion. The study demonstrates that TRU, and consequently PCR, can be estimated by on-line measurement of the UV absorption in the spent dialysate.

    Keywords
    dialysis adequacy; haemodialysis monitoring; protein catabolic rate; total removed urea; urea; UV absorption
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14192 (URN)10.1093/ndt/gfi026 (DOI)
    Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2009-06-05
    3. Dialysis dose (Kt/V) and clearance variation sensitivity using measurement of ultraviolet-absorbance (on-line), blood urea, dialysate urea and ionic dialysance
    Open this publication in new window or tab >>Dialysis dose (Kt/V) and clearance variation sensitivity using measurement of ultraviolet-absorbance (on-line), blood urea, dialysate urea and ionic dialysance
    2006 (English)In: Nephrology Dialysis Transplantation, ISSN 0931-0509, Vol. 21, no 8, p. 2225-2231Article in journal (Refereed) Published
    Abstract [en]

    Background. An on-line monitoring system for dialysis dose calculations could make it possible to provide an adequate dialysis dose that is consistently given to haemodialysis (HD) patients. The aim of this study was to compare dialysis dose (Kt/V) using four different methods and their sensitiveness to a reduction in clearance.

    Methods. Six patients were monitored on-line with ultraviolet (UV)-absorbance at a wavelength of 297 nm in three consecutive dialysis sessions during 1 week. During the last treatment, the clearance was reduced by 25% by decreasing the blood flow. For the determination of UV-absorbance, a spectrophotometer was connected to the fluid outlet of the dialysis machine with all spent dialysate passing through a flow cuvette. The equilibrated Kt/V (eKt/V) estimated by UV-absorbance was compared with eKt/V from the ionic dialysance method using the on-line clearance monitor (OCM) and the appurtenant software dose-calculation tool DCTool (Fresenius Medical Care, Germany), eKt/V calculated from the dialysate-urea slope and with eKt/V from pre- and post-dialysis blood-urea samples as reference.

    Results. The study demonstrates that the sensitiveness to clearance reduction is similar in the four methods compared for eKt/V. When the different methods were compared, the mean eKt/V of UV-absorbance was 1.21 ± 0.20, blood 1.30 ± 0.21, dialysate 1.32 ± 0.21 and OCM (using the DCTool) 1.31 ± 0.21. The standard deviation was of the same magnitude.

    Conclusion. The UV-method gives a similar response to clearance reduction compared with the other methods when comparing dialysis dose. The high sampling rate by continuous monitoring of UV-absorbance allows evaluation of the clearance process during dialysis and gives immediate feedback to on-line adjustments.

    Keywords
    clearance; haemodialysis monitoring; ionic dialysance; Kt/V; ultra violet absorption; urea
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14193 (URN)10.1093/ndt/gfl147 (DOI)
    Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2009-06-05
    4. Ultra violet absorbance on-line measurement utilized to monitor clinical events during haemodialysis
    Open this publication in new window or tab >>Ultra violet absorbance on-line measurement utilized to monitor clinical events during haemodialysis
    2006 (English)In: Journal of Renal Care, ISSN 1755-6678, E-ISSN 1755-6686, Vol. 32, no 3, p. 141-146Article in journal (Refereed) Published
    Abstract [en]

    Background: On-line monitoring systems of the spent dialysate, used to estimate dialysis dose, have been developed with different instrumentation during the last two decades. The routine use of an on-line monitoring system has been suggested to provide to give an adequate dialysis dose to the haemodialysis (HD) patients. The aim of this study was to show that monitoring the spent dialysate using UV-absorbance may bring new information about the clearance process. Methods: 108 HD treatments distributed among 16 clinical stable patients were monitored on-line using ultra violet (UV) absorbance. For the measurement of UV-absorbance a spectrophotometer was connected to the fluid outlet of the dialysis machine with all spent dialysate passing through a flow cuvette. The UV-absorbance curves were examined in combination with the recorded observations of events that occurred during the studied treatments.Results: The study demonstrates that UV-absorbance visualizes different kind of events such as hypotension, conductivity alarms, restricted flow in artery needle blood pump stop that often occur during dialysis treatment.Conclusion: An on-line UV-monitoring system with a high sampling rate makes it possibility to identify variations in dialysis clearance of different origin and gives feedback after performing interventions during a dialysis session

    Keywords
    dialysis adequacy; dialysis clearance; haemodialysis monitoring; on-line adjustments; ultra violet absorption
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14194 (URN)17393808 (PubMedID)
    Note

    Tidigare titel: [On line monitoring using ultraviolet absorption for surveillance of clinical events during hemodialysis]

    Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2017-12-13
    5. Complementary parameter for dialysis monitoring based on UV absorbance
    Open this publication in new window or tab >>Complementary parameter for dialysis monitoring based on UV absorbance
    2009 (English)In: Hemodialysis International, ISSN 1492-7535, E-ISSN 1542-4758, Vol. 13, no 4, p. 492-497Article in journal (Refereed) Published
    Abstract [en]

    An optical on-line monitoring system aimed at the estimation of dialysis dose has been tested clinically. The natural logarithmic slope is used to calculate Kt/V(urea) from ultraviolet (UV)-absorbance measurements. Errors in the calculation of Kt/V(urea) may appear due to changes in blood and dialysate flow or due to disturbances when the slope is used to estimate dialysis dose. This study introduces a new parameter for dialysis monitoring that may be used as a complementary parameter, the area under UV-absorbance curve (AUCa), to reflect a total solute removal during dialysis. The aim was to investigate the relationship between this new dialysis on-line monitoring parameter, AUCa, and the total removal of a few solutes. Fifteen patients were monitored during hemodialysis using UV absorbance at the wavelength of 297 nm. All spent dialysate passed through a flow cuvette in a spectrophotometer and then further to a collection tank where solute concentrations in the entire spent dialysate were determined. The AUCa at 297 nm was compared with the total amount of removed solute in the tank (reference method). The result shows strong correlations between AUCa and the total removal of urea, urate, creatinine, and phosphate during a given treatment and less strong correlation in all 15 patients together. A first indication of a new, possible, complementary parameter in hemodialysis treatment is presented, the AUCa, prospected to estimate solute removal.

    Keywords
    Area under curve, on-line monitoring, solute removal, total dialysate collection, UV absorbance
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14195 (URN)10.1111/j.1542-4758.2009.00381.x (DOI)
    Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2017-12-13
  • 46.
    Uhlin, Fredrik
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Nephrology.
    On-line mätning av uremiska toxiner2014Conference paper (Other academic)
  • 47.
    Uhlin, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nephrology.
    Uv-ljus för att övervaka bloddialys2006In: Dialäsen : tidningen för personal inom njursjukvård, ISSN 1104-4616, Vol. 1, p. 30-31Article in journal (Other academic)
  • 48.
    Uhlin, Fredrik
    Linköping University, Department of Medicine and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Nephrology UHL.
    VOLUPRES -ett trådlöst optiskt system för dialysövervakning2010In: Incitament, ISSN 1103-503X, no 3, p. 227-229Article in journal (Other (popular science, discussion, etc.))
  • 49.
    Uhlin, Fredrik
    et al.
    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 Nephrology UHL.
    Fernström, Anders
    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 Nephrology UHL.
    Från traditionell hemodialys (HD) till hemodiafiltration (HDF)2010In: Incitament, ISSN 1103-503X, no 2, p. 135-139Article in journal (Other (popular science, discussion, etc.))
  • 50.
    Uhlin, Fredrik
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Nephrology. Tallinn Univ Technol, Estonia.
    Fernström, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Nephrology.
    Knapen, Marjo H. J.
    Maastricht Univ, Netherlands.
    Vermeer, Cees
    Maastricht Univ, Netherlands.
    Magnusson, Per
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Chemistry. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Long-term follow-up of biomarkers of vascular calcification after switch from traditional hemodialysis to online hemodiafiltration2019In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 79, no 3, p. 174-181Article in journal (Refereed)
    Abstract [en]

    Rapid progression of vascular calcification (VC) in hemodialysis (HD) patients is caused by several factors including inflammation and an imbalance between active inducers and inhibitors of VC. Growing evidence shows that online hemodiafiltration (ol-HDF), a combination of diffusive and convective solute transport, has positive effects on the uremic environment that affects patients on dialysis. However, we recently reported that serum 25-hydroxyvitamin D (25(OH)D) decreased after a switch from HD to ol-HDF. As a consequence of this finding, the present study was undertaken to investigate if inducers and inhibitors of VC (i.e. the inactive matrix Gla protein fractions dp-ucMGP and t-ucMGP, fetuin-A, Gla-rich protein (GRP), osteopontin (OPN), bone-specific alkaline phosphatase (BALP), and osteoprotegerin (OPG)) also are affected by ol-HDF. This non-comparative prospective study comprised 35 prevalent patients who were investigated 6, 12, and 24 months after their switch from HD to ol-HDF. Most patients had increased levels of the calcification inhibitors OPN and OPG; and of the inactive calcification inhibitor dp-ucMGP during the study period irrespective of the dialysis modality. BALP and t-ucMGP were mostly within the reference interval, but fetuin-A was mostly below the reference interval during the study period. OPN was significantly associated with BALP and parathyroid hormone, r = 0.62 and r = 0.65 (p amp;lt; .001), respectively. In conclusion, in contrast to decreased 25(OH)D levels, no differences were found for any of the measured biomarkers of VC following the switch from HD to ol-HDF. Further studies are needed to elucidate how these biomarkers can contribute to calcification risk assessment.

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  • text
  • asciidoc
  • rtf