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  • 1.
    Ask, Per
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    EDWALL, G
    Tibbling, Lita
    ESOPHAGEAL PH MEASUREMENTS USING AN ANTIMONY ELECTRODE1980In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 18, no 1Article in journal (Refereed)
  • 2.
    Ask, Per
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Öberg, Åke
    Linköping University, Department of Biomedical Engineering.
    Tibbling, Lita
    ESOPHAGEAL MANOMETRY - DETERMINATION OF BANDWIDTH REQUIREMENTS BY SIGNAL ANALYSIS1980In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 25, no 5Article in journal (Refereed)
  • 3.
    Cardemil, Carina
    Department of Biomaterials, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden.
    Effects of antiresorptive agents on inflammation and bone regeneration in different osseous sites - experimental and clinical studies2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The biological mechanisms involved in bone regeneration in osteoporotic bone and the effect of antiresorptive drugs in relation to surgically inserted biomaterials are not fully understood. Improved osseointegration of titanium implants but also adverse effects of antiresorptive therapies, such as osteonecrotic jaw have been described in the literature. The aims of this research project were, firstly, to investigate and to understand the biological events determining bone regeneration and implant integration, after administration of antiresorptive agents; secondly, to determine the cellular and molecular patterns of bone regeneration at implants and synthetic bone substitutes under osteoporotic conditions and, thirdly, to determine how different skeletal sites are affected. The present research included a study of jawbone morphology and gene expression in patients treated with systemic bisphosphonates. When compared to controls, higher gene expression levels of IL-1β was observed in bisphosphonate treated patients with osteonecrosis while bisphosphonate treated patients without necrosis showed lower expression levels of caspase 8, an apoptosis marker involved in the immune response. In ovariectomised rats, zoledronic acid resulted in site-specific differences in the rate of osseointegration and also of gene expression involved in bone healing and regeneration. Strontium-doped calcium phosphate inserted in the rat femur induced lower expression of osteoclastic markers compared to hydroxyapatite and higher bone formation in the periphery of the defects. Whereas major structural changes were demonstrated in the long bones of the ovariectomised rat, less structural alterations were shown in the mandible. However, ovariectomy resulted in lower expression of genes coding for bone formation and angiogenesis in the mandible. In conclusion, the present study shows that the mandible is differently affected by experimentally induced estrogen deficiency than the long bones. Bisphosphonates, administered systemically to estrogen deficient animals, impair osseointegration in the mandible, at least partly related to a downregulation of genes important for the osteogenic process. These observations may have implications for understanding the mechanisms involved in the deranged bone healing observed in the jawbone of bisphosphonate treated patients.

    List of papers
    1. The effects of a systemic single dose of zoledronic acid on post-implantation bone remodelling and inflammation in an ovariectomised rat model.
    Open this publication in new window or tab >>The effects of a systemic single dose of zoledronic acid on post-implantation bone remodelling and inflammation in an ovariectomised rat model.
    Show others...
    2013 (English)In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 34, no 5, p. 1546-1561Article in journal (Refereed) Published
    Abstract [en]

    Bisphosphonates reverse the negative effects of ovariectomy on bone, but they have also been associated with adverse processes in human jawbone. The molecular events determining bone regeneration and implant integration in osteoporotic conditions, with and without bisphosphonate treatment, are unclear. In this study, ovariectomised rats, to which a single dose of saline (NaCl) or zoledronic acid (Zol) was administered, received titanium alloy implants in their tibiae and mandibles. An enzyme-linked immunosorbent assay, gene expression analysis and histomorphometry were performed. The results show that ovariectomy, per se, upregulated the expression of genes denoting bone formation in the tibia, bone remodelling in the mandible and apoptosis in the tibia and mandible. Zoledronic acid administration resulted in lower levels of a remodelling marker in serum and downregulated gene expression for inflammation, bone formation, angiogenesis and apoptosis, mainly in the mandible, after 28 d of healing. Histomorphometry revealed improved bone-to-implant contact in the tibia, while the opposite was observed in the mandible. The present data show that a systemic single dose of zoledronic acid, in ovariectomised animals, results in site-specific differences in the regulation of genes involved in bone healing and regeneration in association with implant installation. These events occur in parallel with site-specific differences in the rate of osseointegration, indicating diverse tissue responses in the tibia and mandible after zoledronic acid treatment. The zoledronic acid effect on gene expression, during the late phase of healing in the mandible, suggests negative effects by the anti-resorptive agent on osseointegration at that particular site.

    National Category
    Basic Medicine
    Identifiers
    urn:nbn:se:liu:diva-135755 (URN)10.1016/j.biomaterials.2012.11.003 (DOI)23182921 (PubMedID)
    Available from: 2017-03-21 Created: 2017-03-21 Last updated: 2018-01-13
    2. Strontium-doped calcium phosphate and hydroxyapatite granules promote different inflammatory and bone remodelling responses in normal and ovariectomised rats
    Open this publication in new window or tab >>Strontium-doped calcium phosphate and hydroxyapatite granules promote different inflammatory and bone remodelling responses in normal and ovariectomised rats
    Show others...
    2013 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 12, article id e84932Article in journal (Refereed) Published
    Abstract [en]

    The healing of bone defects may be hindered by systemic conditions such as osteoporosis. Calcium phosphates, with or without ion substitutions, may provide advantages for bone augmentation. However, the mechanism of bone formation with these materials is unclear. The aim of this study was to evaluate the healing process in bone defects implanted with hydroxyapatite (HA) or strontium-doped calcium phosphate (SCP) granules, in non-ovariectomised (non-OVX) and ovariectomised (OVX) rats. After 0 (baseline), six and 28d, bone samples were harvested for gene expression analysis, histology and histomorphometry. Tumour necrosis factor-α (TNF-α), at six days, was higher in the HA, in non-OVX and OVX, whereas interleukin-6 (IL-6), at six and 28d, was higher in SCP, but only in non-OVX. Both materials produced a similar expression of the receptor activator of nuclear factor kappa-B ligand (RANKL). Higher expression of osteoclastic markers, calcitonin receptor (CR) and cathepsin K (CatK), were detected in the HA group, irrespective of non-OVX or OVX. The overall bone formation was comparable between HA and SCP, but with topological differences. The bone area was higher in the defect centre of the HA group, mainly in the OVX, and in the defect periphery of the SCP group, in both non-OVX and OVX. It is concluded that HA and SCP granules result in comparable bone formation in trabecular bone defects. As judged by gene expression and histological analyses, the two materials induced different inflammatory and bone remodelling responses. The modulatory effects are associated with differences in the spatial distribution of the newly formed bone.

    National Category
    Biomaterials Science Medical Materials Medical Biotechnology Cell and Molecular Biology
    Identifiers
    urn:nbn:se:liu:diva-136113 (URN)10.1371/journal.pone.0084932 (DOI)24376855 (PubMedID)
    Available from: 2017-03-28 Created: 2017-03-28 Last updated: 2018-01-13Bibliographically approved
  • 4.
    Cardemil, Carina
    et al.
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, Department of Oral and Maxillofacial Surgery, Örebro University Hospital, Örebro, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden .
    Elgali, Ibrahim
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Xia, Wei
    Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Emanuelsson, Lena
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Norlindh, Birgitta
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Omar, Omar
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden.
    Thomsen, Peter
    Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden, BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg, Sweden .
    Strontium-doped calcium phosphate and hydroxyapatite granules promote different inflammatory and bone remodelling responses in normal and ovariectomised rats2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 12, article id e84932Article in journal (Refereed)
    Abstract [en]

    The healing of bone defects may be hindered by systemic conditions such as osteoporosis. Calcium phosphates, with or without ion substitutions, may provide advantages for bone augmentation. However, the mechanism of bone formation with these materials is unclear. The aim of this study was to evaluate the healing process in bone defects implanted with hydroxyapatite (HA) or strontium-doped calcium phosphate (SCP) granules, in non-ovariectomised (non-OVX) and ovariectomised (OVX) rats. After 0 (baseline), six and 28d, bone samples were harvested for gene expression analysis, histology and histomorphometry. Tumour necrosis factor-α (TNF-α), at six days, was higher in the HA, in non-OVX and OVX, whereas interleukin-6 (IL-6), at six and 28d, was higher in SCP, but only in non-OVX. Both materials produced a similar expression of the receptor activator of nuclear factor kappa-B ligand (RANKL). Higher expression of osteoclastic markers, calcitonin receptor (CR) and cathepsin K (CatK), were detected in the HA group, irrespective of non-OVX or OVX. The overall bone formation was comparable between HA and SCP, but with topological differences. The bone area was higher in the defect centre of the HA group, mainly in the OVX, and in the defect periphery of the SCP group, in both non-OVX and OVX. It is concluded that HA and SCP granules result in comparable bone formation in trabecular bone defects. As judged by gene expression and histological analyses, the two materials induced different inflammatory and bone remodelling responses. The modulatory effects are associated with differences in the spatial distribution of the newly formed bone.

  • 5.
    Ghareh Baghi, Ghareh Baghi
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Assessment of Valvular Aortic Stenosis by Signal Analysis of the Phonocardiogram2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Aortic stenosis (AS) is one of the most prevalent valvular heart diseases in elderly people. According to the recommendations of both the American Heart Association and the European Society of Cardiology, severity assessment of AS is primarily based on echocardiographic findings. The experience of the investigator here play important roles in the accuracy of the assessment, and therefore in the disease management. However, access to the expert physicians could be limited, especially in rural health care centers of developing countries.

    This thesis aims to develop processing algorithms tailored for phonocardiographic signal with the intension to obtain a noninvasive diagnostic tool for AS assessment and severity grading. The algorithms employ a phonocardiogram as input signal and perform analysis for screening and diagnostics. Such a decision support system, which we call “the intelligent phonocardiography”, can be widely used in primary healthcare centers.

    The main contribution of the thesis is to present innovative models for the phonocardiographic analysis by taking the segmental characteristics of the signal into consideration. Three novel methodologies are described, based on the presented models, to perform robust classification. In the first attempt, a novel pattern recognition framework is presented for screening of AS-related murmurs. The framework offers a hybrid model for classifying cyclic time series in general, but is tailored to detect the murmurs as a special case study. The time growing neural network is another method that we use to classify short time signals with abrupt frequency transition. The idea of the growing frames is extended to the cyclic signals with stochastic properties for the screening purposes. Finally, a combined statistical and artificial intelligent classifier is proposed for grading the severity of AS.

    The study suggests comprehensive statistical validations not only for the evaluation and representation of systolic murmurs but also for setting the methodology design parameters, which can be considered as one of the significant features of the study. The resulting methodologies can be implemented by using web and mobile technologies to be utilized in distributed healthcare system.

    List of papers
    1. A pattern recognition framework for detecting dynamic changes on cyclic time series
    Open this publication in new window or tab >>A pattern recognition framework for detecting dynamic changes on cyclic time series
    2015 (English)In: Pattern Recognition, ISSN 0031-3203, E-ISSN 1873-5142, Vol. 48, no 3, p. 696-708Article in journal (Refereed) Published
    Abstract [en]

    This paper proposes a framework for binary classification of the time series with cyclic characteristics. The framework presents an iterative algorithm for learning the cyclic characteristics by introducing the discriminative frequency bands (DFBs) using the discriminant analysis along with k-means clustering method. The DFBs are employed by a hybrid model for learning dynamic characteristics of the time series within the cycles, using statistical and structural machine learning techniques. The framework offers a systematic procedure for finding the optimal design parameters associated with the hybrid model. The proposed  model is optimized to detect the changes of the heart sound recordings (HSRs) related to aortic stenosis. Experimental results show that the proposed framework provides efficient tools for classification of the HSRs based on the heart murmurs. It is also evidenced that the hybrid model, proposed by the framework, substantially improves the classification performance when it comes to detection of the heart disease.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keywords
    Hybrid model, cyclic time series, time series, phonocardiogram, systolic murmurs
    National Category
    Biomedical Laboratory Science/Technology Medical Biotechnology
    Identifiers
    urn:nbn:se:liu:diva-110177 (URN)10.1016/j.patcog.2014.08.017 (DOI)000347747000008 ()
    Available from: 2014-09-04 Created: 2014-09-04 Last updated: 2017-12-05Bibliographically approved
    2. Detection of systolic ejection click using time growing neural network
    Open this publication in new window or tab >>Detection of systolic ejection click using time growing neural network
    2014 (English)In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 36, no 4, p. 477-483Article in journal (Refereed) Published
    Abstract [en]

    In this paper, we present a novel neural network for classification of short-duration heart sounds: the time growing neural network (TGNN). The input to the network is the spectral power in adjacent frequency bands as computed in time windows of growing length. Children with heart systolic ejection click (SEC) and normal children are the two groups subjected to analysis. The performance of the TGNN is compared to that of a time delay neural network (TDNN) and a multi-layer perceptron (MLP), using training and test datasets of similar sizes with a total of 614 normal and abnormal cardiac cycles. From the test dataset, the classification rate/sensitivity is found to be 97.0%/98.1% for the TGNN, 85.1%/76.4% for the TDNN, and 92.7%/85.7% for the MLP. The results show that the TGNN performs better than do TDNN and MLP when frequency band power is used as classifier input. The performance of TGNN is also found to exhibit better immunity to noise.

    Place, publisher, year, edition, pages
    Elsevier, 2014
    Keywords
    Systolic ejection click; Time growing neural network; Time delay neural network; Heart sound
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-106865 (URN)10.1016/j.medengphy.2014.02.011 (DOI)000334976800008 ()
    Available from: 2014-05-28 Created: 2014-05-23 Last updated: 2017-12-05
    3. A novel method for discrimination between innocent and pathological heart murmurs
    Open this publication in new window or tab >>A novel method for discrimination between innocent and pathological heart murmurs
    2015 (English)In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 37, no 7, p. 674-682Article in journal (Refereed) Published
    Abstract [en]

    This paper presents a novel method for discrimination between innocent and pathological murmurs using the growing time support vector machine (GTSVM). The proposed method is tailored for characterizing innocent murmurs (IM) by putting more emphasis on the early parts of the signal as IMs are often heard in early systolic phase. Individuals with mild to severe aortic stenosis (AS) and IM are the two groups subjected to analysis, taking the normal individuals with no murmur (NM) as the control group. The AS is selected due to the similarity of its murmur to IM, particularly in mild cases. To investigate the effect of the growing time windows, the performance of the GTSVM is compared to that of a conventional support vector machine (SVM), using repeated random sub-sampling method. The mean value of the classification rate/sensitivity is found to be 88%/86% for the GTSVM and 84%/83% for the SVM. The statistical evaluations show that the GTSVM significantly improves performance of the classification as compared to the SVM.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keywords
    Growing-time support vector machine, support vector machine, phonocardiogram signal, heart murmurs, innocent murmurs.
    National Category
    Medical Engineering
    Identifiers
    urn:nbn:se:liu:diva-117825 (URN)10.1016/j.medengphy.2015.04.013 (DOI)000357354400007 ()26003286 (PubMedID)
    Note

    At the time for thesis presentation publication was in status: Manuscript

    Available from: 2015-05-08 Created: 2015-05-08 Last updated: 2017-12-04Bibliographically approved
    4. An Automatic Tool for Pediatric Heart Sounds Segmentation
    Open this publication in new window or tab >>An Automatic Tool for Pediatric Heart Sounds Segmentation
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    In this paper, we present a novel algorithm for pediatric heart sound segmentation, incorporated into a graphical user interface. The algorithm employs both the Electrocardiogram (ECG) and Phonocardiogram (PCG) signals for an efficient segmentation under pathological circumstances.First, the ECG signal is invoked in order to determine the beginning and end points of each cardiac cycle by using wavelet transform technique. Then, first and second heart sounds within the cycles are identified over the PCG signal by paying attention to the spectral properties of the sounds. The algorithm is applied on 120 recordings of normal and pathological children, totally containing 1976 cardiac cycles. The accuracy of the segmentation algorithm is 97% for S1 and 94% for S2 identification while all the cardiac cycles are correctly determined.

    National Category
    Biomedical Laboratory Science/Technology Medical Biotechnology
    Identifiers
    urn:nbn:se:liu:diva-110179 (URN)
    Available from: 2014-09-04 Created: 2014-09-04 Last updated: 2014-09-04Bibliographically approved
    5. Severity assessments of aortic stenosis using intelligent phonocardiography
    Open this publication in new window or tab >>Severity assessments of aortic stenosis using intelligent phonocardiography
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Objectives: To study capabilities of the intelligent phonocardiography (IPCG) in automatic grading severity of the aortic stenosis (AS).

    Methods: Phonocardiogram signals were recorded from the patients with AS, as diagnosed by echocardiography. The patient group is comprised of signals, recorded from 5 patients (2 recordings from each), mostly elderly referrals (>60 years) with mild to severe AS. An advanced processing algorithm, consisted of the wavelet transform and the stepwise regression analysis, characterizes the systolic murmur caused by the AS in order to predict the 5 indicators; mean pressure gradient over the aortic valve (MPG), maximum jet velocity (MJV), aortic valve area (AVA), velocity time integral and the ejection period. The automatic assessment is performed by an artificial neural network using the predicted values of the indicators as the input data. Reliability of the IPCG is validated by applying repeated random sub-sampling (RRSS) with 70%/30% of the training/testing data, and calculating the accuracy. The RRSS is also employed to validate reproducibility of the IPCG by using 70% of the signals for training and the second recording of the same individuals for  testing.

    Results: Accuracy of the IPCG is estimated to be and (95% confidence interval) for the reliability and the reproducibility, respectively. Linear correlation between the characterized systolic murmur and the MPG (r>0.81), the MJV (r>0.82) and the AVA (r>0.85) is observed.

    Conclusions: The IPCG has the potential to objectively serve as a clinical tool for grading severity of the aortic stenosis.

    National Category
    Biomedical Laboratory Science/Technology Medical Biotechnology
    Identifiers
    urn:nbn:se:liu:diva-110181 (URN)
    Available from: 2014-09-04 Created: 2014-09-04 Last updated: 2014-09-04Bibliographically approved
  • 6. HULTEN, J
    et al.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    A DEVICE FOR BLADDER PRESSURE MONITORING DURING TRANS-URETHRAL RESECTION1984In: Scandinavian Journal of Urology and Nephrology, ISSN 0036-5599, E-ISSN 1651-2065, no 82, p. 75-80Article in journal (Refereed)
  • 7. JOHANSSON, KE
    et al.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    EDWALL, G
    Tibbling, Lita
    A PORTABLE UNIT FOR 24-HOUR ESOPHAGEAL PH MONITORING WITH ANTIMONY ELECTRODES1981In: ACTA CHIRURGICA SCANDINAVICA, ISSN 0001-5482, no 506Article in journal (Refereed)
  • 8.
    Lantz, Jonas
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wren, Joakim
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Heating in a Stenosed Coronary Artery With Pulsating Flow and Non-Newtonian Viscosity2009In: ASME 2008 Summer Bioengineering Conference: Parts A and B, The American Society of Mechanical Engineers (ASME) , 2009, no PART A, p. 331-332Conference paper (Refereed)
    Abstract [en]

    Cardiovascular disease is the most prevalent cause of death in the developed countries and most deaths are due to coronary atherosclerosis [1]. During the development of atherosclerosis, several stages can be distinguished including vulnerable plaque. This group of plaque has an inclination for erosion and rupture and is therefore of particular interest. Due to the inflammatory response of vulnerable plaque including an increased metabolism and thereby a locally increased temperature, it is possible to detect such warm cores by intracoronally temperature measurement under some prerequisitions. Temperature differences up to 2.2 K on the surface of carotid plaques have been measured [2], but the relation between plaque vulnerability, inflammatory response, temperature increase and possibility to detection by means of temperature measurement is far from fully perceived.

  • 9.
    Loyd, Dan
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Doppler prediction of transvalvular gradient and stenotic orifice area.1988In: American Journal of Cardiology, ISSN 0002-9149, E-ISSN 1879-1913, Vol. 61, no 11, p. 958-959Article in journal (Refereed)
  • 10.
    Loyd, Dan
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    BARCLAY, SA
    XIONG, Changsheng
    ANDERSSON, Gunnar
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    ECHOCARDIOGRAPHIC ASSESSMENT OF HEART-VALVE REGURGITANT FLOW USING THE FLOW CONVERGENCE METHOD1991In: PROCEEDINGS OF THE ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOL 13, PTS 1-5, 1991, p. 191-192Conference paper (Refereed)
  • 11.
    Nyman, Erika
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Henricson, Joakim
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Rakar, Jonathan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences.
    Olausson, Patrik
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Anderson, Chris
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Dermatology and Venerology.
    Kratz, Gunnar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Exogenous hyaluronic acid induces accelerated re-epithelialization and altered protein expression in adult human skin wounds in vivoManuscript (preprint) (Other academic)
    Abstract [en]

    Background

    Hyaluronic acid, a large glycosaminoglycan involved in proliferation, migration, and tissue repair, is suggested to play an important role in ideal scarless fetal wound healing. This study aimed to investigate the effect of exogenous hyaluronic acid intradermal during deep dermal wound healing. Study parameters were erythema, re-epithelialization, and protein expression examined by using a previously described, minimally invasive in vivo human wound model in combination with tissue viability imaging, histology, and proteomics.

    Methods

    Standardized deep dermal wounds were created in the ventral forearm in ten healthy volunteers using blood collection lancets. The wound sites were injected with hyaluronic acid or saline solution, prior to wounding, or were left untreated. To quantify changes in red blood cell concentration as a measurement of inflammation, the study sites were photographed daily for two weeks using a tissue viability imaging system. At 24 hours and after 14 days, biopsy specimens were taken for histology and proteomics analysis.

    Results

    The inflammatory response was not affected by the injection of hyaluronic acid, as measured by tissue viability imaging. Hyaluronic acid significantly induced (p < 0.05) accelerated reepithelialization at 24 hours, and wounds treated with hyaluronic acid showed an altered protein expression.

    Conclusion

    The results from the present study are in concordance with  previous in vitro findings and suggest that exogenous hyaluronic acid has a  positive effect on the healing process of cutaneous wounds. We conclude that hyaluronic acid injected intradermally induces accelerated re-epithelialization and alters protein expression in vivo in human deep dermal skin wounds.

  • 12.
    Persson, Anna
    Linköping University, Department of Physics, Chemistry and Biology.
    Non-vitamin K dependent oral anticoagulants (NOACs) controls2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years non-vitamin K dependent oral anticoagulants (NOACs) have started to replace warfarin for treatment and prevention of deep venous thrombosis (DVT), pulmonary embolism (PE) and stroke in patients with and without atrial fibrillation. There is a need for a simple and rapid method to detect the presence of these drugs in patient plasma. To meet these new demands, MediRox is developing a screening assay based on a novel prothrombin time (PT) method for rapid detection of NOACs in plasma. The assay is semi-quantitative and by dividing the International Normalised Index (INR) from a NOAC sensitive PT method with the INR from a NOAC insensitive PT method, NOAC containing samples be detected while plasma from normal donors and with warfarin are excluded.

     

    The purpose of this project is to develop prototypes of assay quality controls for detection of NOACs in plasma.

     

    The results show that the method used for the NOAC control prototypes is applicable and the PT ratio is comparable to patient samples for the low, medium and high concentrations of NOAC. The effect of lyophilisation indicates that the PT ratios for the NOAC control prototypes were nearly unaffected by the lyophilisation. The in-use stability at room temperature (20-25oC) for all NOAC control prototypes were at least 24 hours.

     

    The methodology for production needs to be further optimised to increase the commutability to patient samples with very high concentrations of NOAC. The data indicates that the effect of lyophilisation is minimal and the stability of the NOAC control prototypes are satisfying, which is promising for future product development of NOAC controls. 

  • 13. POPE, CE
    et al.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    DEBLAN, H
    WINGATE, DL
    MEASUREMENT OF INSTANTANEOUS FLOW VELOCITY IN THE HUMAN GASTROINTESTINAL-TRACT1988In: Gastroenterology, ISSN 0016-5085, E-ISSN 1528-0012, Vol. 95, no 3Article in journal (Refereed)
  • 14.
    Rattfält, Linda
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology. Biomedical Engineering, Örebro County Council, Örebro, Sweden.
    Ahlström, Christer
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology. Biomedical Engineering, Örebro County Council, Örebro, Sweden.
    Eneling, Martin
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Ragnemalm, Bengt
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Hult, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements. Biomedical Engineering, Örebro County Council, Örebro, Sweden.
    Lindén, M.
    Intelligent Sensor Systems, Mälardalen University, Västerås, Sweden.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology. Biomedical Engineering, Örebro County Council, Örebro, Sweden.
    A platform for physiological signals including an intelligent stethoscope2009In: 4th European Conference of the International Federation for Medical and Biological Engineering: ECIFMBE 2008 23–27 November 2008 Antwerp, Belgium / [ed] Jos Sloten, Pascal Verdonck, Marc Nyssen, Jens Haueisen, Springer Berlin/Heidelberg, 2009, Vol. 22, p. 1038-1041Chapter in book (Refereed)
    Abstract [en]

    We have developed a physiological signal platform where presently phonocardiographic (PCG) and electrocardiographic (ECG) signals can be acquired and on which our signal analysis techniques can be implemented. The platform can also be used to store patient data, to enable comparison over time and invoke distance consultation if necessary. Our studies so far indicate that with our signal analysis techniques of heart sounds we are able to separate normal subject from those with aortic stenosis and mitral insufficiency. Further we are able to identify the third heart sound. The platform is being tested in a primary health care setting.

  • 15.
    Renner, Johan
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Gårdhagen, Roland
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Subject Specific In-Vivo CFD Estimated Aortic WSS: Comparison Between Manual and Automated Segmentation Methods2009In: ASME 2008 Summer Bioengineering Conference: Parts A and B, The American Society of Mechanical Engineers (ASME) , 2009, no PART A, p. 425-426Conference paper (Refereed)
    Abstract [en]

    When making computational fluid dynamics (CFD) based estimations of wall shear stress (WSS) in the human aorta, medical image converting processes to 3D geometries are important as the result is strongly dependent on the quality of the geometry [1]. The image interpretation process or segmentation can be more or less automated; however in clinical work today the gold standard is to manually interpret the medical image information. This combined magnetic resonance imaging (MRI) and CFD method aims to estimate WSS in human arteries in-vivo as WSS is strongly linked to atherosclerosis [2]. More or less automated segmentation has been used in previous studies but normally based on a stack of 2D individually segmented slices which is combined into a 3D model [3]. The aim of this work is to compare manual 2D and automatic 3D segmentations.

  • 16.
    Samuelsson, Johanna
    Linköping University, Department of Medical and Health Sciences.
    Visualization of Regional Liver Function with Hepatobiliary Contrast Agent Gd-EOB-DTPA2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Liver biopsy is a very common, but invasive procedure for diagnosing liver disease. However, such a biopsy may result in severe complications and in some cases even death. Therefore, it would be highly desirable to develop a non-invasive method which would provide the same amount of information on staging of the disease and also the location of pathologies. This thesis describes the implementation of such a non-invasive method for visualizing and quantifying liver function by the combination of MRI (Magnetic Resonance Imaging), image reconstruction, and image analysis, and pharmacokinetic modeling. The first attempt involved automatic segmentation, functional clustering (k-means) and classification (kNN) of in-data (liver, spleen and blood vessel segments) in the pharmacokinetic model. However, after implementing and analyzing this method some important issues were identified and the image segmentation method was therefore revised. The segmentation method that was subsequently developed involved a semi-automatic procedure, based on a modified image forest transform (IFT). The data were then simulated and optimized using a pharmacokinetic model describing the pharmacokinetics of the liver specific contrast agent Gd-EOB-DTPA in the human body. The output from the modeling procedure was then further analyzed, using a least-squares method, in order to assess liver function by estimating the fractions of hepatocytes, extracellular extravascular space (EES) and blood plasma in each voxel of the image. The result were in fair agreement with literature values, although further analyses and developments will be required in order to validate and also to confirm the accuracy of the method.

  • 17. Spånberg, Anders
    et al.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    ENGBERG, Anders
    TERIO, Hikki
    URODYNAMIC ASSESSMENT OF OBSTRUCTION - SHOULD IT BE EVALUATED ACCORDING TO GRIFFITHS OR SCHAFER MODEL1987In: Scandinavian Journal of Urology and Nephrology, ISSN 0036-5599, E-ISSN 1651-2065, no 105Article in journal (Refereed)
  • 18. Tibbling, Lita
    et al.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Öberg, Åke
    Linköping University, Department of Biomedical Engineering.
    ACCURACY AND VALIDITY OF ESOPHAGEAL MANOMETRY SYSTEMS1980In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 25, no 5Article in journal (Refereed)
  • 19.
    Turkina, Maria
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences.
    Ghafouri, Nazdar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Evaluation of dynamic changes in interstitial fluid proteome following microdialysis probe insertion trauma in trapezius muscle of healthy women2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 43512Article in journal (Refereed)
    Abstract [en]

    Microdialysis ( MD) has been shown to be a promising technique for sampling of biomarkers. Implantation of MD probe causes an acute tissue trauma and provokes innate response cascades. In order to normalize tissue a two hours equilibration period for analysis of small molecules has been reported previously. However, how the proteome profile changes due to this acute trauma has yet to be fully understood. To characterize the early proteome events induced by this trauma we compared proteome in muscle dialysate collected during the equilibration period with two hours later in "post-trauma". Samples were collected from healthy females using a 100 kDa MW cut off membrane and analyzed by high sensitive liquid chromatography tandem mass spectrometry. Proteins involved in stress response, immune system processes, inflammatory responses and nociception from extracellular and intracellular fluid spaces were identified. Sixteen proteins were found to be differentially abundant in samples collected during first two hours in comparison to "post-trauma". Our data suggests that microdialysis in combination with mass spectrometry may provide potentially new insights into the interstitial proteome of trapezius muscle, yet should be further adjusted for biomarker discovery and diagnostics. Moreover, MD proteome alterations in response to catheter injury may reflect individual innate reactivity.

  • 20.
    Turner, Anthony
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Torrens del Valle, M.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Ortiz, M.
    O'Sullivan, Ciara
    Universitat Rovira i Virgili, Tarragona, Spain.
    Development of alternative for carbon surface functionalisation with diazonium derivative andits application on DNA and protein detections2013In: Doctoral Days, 2013, Tarragona, Spain: Universitat Rovira i Virgili , 2013Conference paper (Other academic)
  • 21.
    Vastesson, Alexander
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Micro-Structuring of New Materials Combined with Electronic Polymers for Interfaces with Cells2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Materials based on novel Off-Stoichiometry Thiol-Ene polymers, abbreviated OSTE, show promising properties as materials forlow cost and scalable manufacturing of micro- and nanosystems such as lab-on-chip devices. The OSTE materials have tunablemechanical properties, offer possibility for low temperature bonding to many surfaces via tunable surface chemistry, and can beused in soft lithography. Unlike the commonly used elastomer poly(dimethylsiloxane), PDMS, the OSTE materials have lowpermeability for gasses, are resistant to common solvents and can be more permanently surface modified.In this master’s thesis project, the OSTE materials have been evaluated with focus on compatibility with cells, possibility fornanostructuring using soft lithography and the use of OSTE as a flexible support for conducting polymers.Results from cell seeding studies with HEP G2 cells suggest that cells can proliferate on a low thiol off-stoichiometry OSTEmaterial for at least five days. The biocompatibility for this type of OSTE material may be similar to poly(styrene). However, highlevels of free thiol monomers in the material decrease cell viability considerably.By using soft lithography techniques it is possible to fabricate OSTE nanochannels with at least the dimensions of 400 nm x 15nm. Combined with the advantages of using the OSTE materials, such as low temperature bonding and possibility for stablesurface modifications, a candidate construction material for future development of systems for DNA analysis is at hand.OSTE can serve as a flexible support for an adsorbed film of a conducting polymer with the possibility for future applicationssuch as electronic interfaces in microsystems. In this project, a film of PEDOT:PSS with the electrical resistance of ~5 kΩ wascreated by adsorption to an flexible OSTE material. Furthermore, results suggest that it is possible to further optimize theconductivity and water resistance of PEDOT:PSS films on OSTE.

  • 22.
    Wren, Joakim
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Andersson, P.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Radiofrequency Thermal Ablation of Liver Tumors: Impact of Large Vessels2009In: ASME 2008 Summer Bioengineering Conference: Parts A and B, The American Society of Mechanical Engineers (ASME) , 2009, no PART B, p. 611-612Conference paper (Refereed)
    Abstract [en]

    Surgical resection is the golden standard for treatment of both primary and metastatic liver tumors, and the method is associated with the highest long-time survival rates [1]. A large number of patients are however not candidates for tumor resection, for example due to un-sufficent hepatic reserve or tumor location relative to large blood vessels. In those cases, an alternative treatment strategy is to heat the tumor(s) to lethal temperatures by means of Radiofrequency (RF) current.

1 - 22 of 22
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