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  • 1. Arsov, S.
    et al.
    Trajceska, L.
    van Oeveren, W.
    Smit, A. J.
    Vidimliski, P. Dzekova
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Sikole, A.
    Rakhorst, G.
    Graaff, R.
    The use of a skin age reader to evaluate risk of cvd and mortality in dialysis patients2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 606-606Article in journal (Other academic)
  • 2. Arsov, S.
    et al.
    Vidimliski, P. Dzekova
    Trajceska, L.
    Graaff, R.
    van Oeveren, W.
    Smit, A. J.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Schalkwijk, C.
    Sikole, A.
    Rakhorst, G.
    Accumulation rate of ages in the skin biopsy tissue of dialysis patients2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 650-650Article in journal (Other academic)
  • 3.
    Brännström, Thomas
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Forsberg, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Ch.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Hultdin, Johan
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Micro embolies of air are deposited in the organs in hemodialysis patients: a case report2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 636-636Article in journal (Other academic)
  • 4.
    Forsberg, Ulf
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Air contamination during medical treatment results in deposits of microemboli in the lungs: an autopsy study2019In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 42, no 9, p. 477-481Article in journal (Refereed)
    Abstract [en]

    Introduction: Microbubbles of air may enter into patients during conventional hemodialysis, infusions of fluids, or by injections. The aim of this study was to investigate whether the air that enters the patient during hemodialysis can be detected in the lungs after death, and if so, whether this may be related to tissue damage. Methods: The material consisted of lung tissue from five chronic hemodialysis patients who died either during (two) or after hemodialysis (range 10 min from start until 3333 min after the last hemodialysis session); as reference group tissue was taken from seven patients who died due to amyotrophic lateral sclerosis. The lung tissue was investigated by microscopy after autopsy using a fluorescein-marked polyclonal antibody against fibrinogen as a marker for clots preformed before death. Results: All five hemodialysis patients had microbubbles of air in the lung tissue, whereas two of seven amyotrophic lateral sclerosis patients had such findings (Fisher's test p = 0.0278, relative risk = 3.5, confidence interval: 1.08-11.3). There were more microbubbles of air/10 randomly investigated microscopic fields of tissue in the hemodialysis patients than the amyotrophic lateral sclerosis patients (Student's test, p < 0.05). All hemodialysis patients had a medium graded extent of pulmonary fibrosis that was not found in any of the ALS patients. The microbubbles of air were surrounded by fibrin as a sign of development of clots around the air bubbles while the patients were still alive. Conclusion: Exposure to microbubbles of air during various treatments such as hemodialysis may result in microemboli. Future studies should clarify whether microbubbles of air contribute to tissue scarring. We suggest preventive measures against the exposure to microbubbles of air during especially repeated exposures such as hemodialysis.

  • 5.
    Fransson, Filip
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Kyrk, Tobias
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Skagerlind, Malin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Rinsing the extra corporeal circuit with a heparin and albumin solution reduces the need for systemic anticoagulant in hemodialysis2013In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 36, no 10, p. 725-729Article in journal (Refereed)
    Abstract [en]

    Background: Systemic anticoagulation during hemodialysis (HD) increases the risk for bleeding complications pre- or post-operatively. Based on the concept of blood-membrane interaction, we developed a heparin-albumin solution to rinse the dialysis circuit before start. The aim of this study was to investigate if this method was a valuable tool for our patients at risk for bleeding complications.

    Material and methods: This retrospective, comparative, quality assessment study included 248 HD in 68 patients; Group 1: 178 treatments were performed at patients for risk of bleeding using heparin-albumin-priming and Group 2: 70 acute HD were performed on patients without increased risk of bleeding using a bolus of heparin at start and a continuous infusion of heparin. In Group 1 additional heparin was given upon suspicion of progressive clotting. One L saline contained albumin (1 g/I) and heparin (5000 U/I) used for priming. Excess priming solution was removed by filling the circuit with blood at start of treatment.

    Results: In Group 1, a mean total dose of 2000 U of heparin was given during the HD (18% performed HD without any heparin) and Group 2 used a mean total dose of 5500 U (p<0.001). There was no increased incidence of clotting in Group 1 versus Group 2 compared to standard HD. No bleeding complications were reported during any of the HA-priming treatments.

    Conclusions: Heparin-albumin priming resulted in a reduced total dose of heparin. There was no increased clotting and no incidence of bleeding was reported in either group.

  • 6. Graaff, R.
    et al.
    Arsov, S.
    Trajceska, L.
    Dzekova, P.
    Engels, G. E.
    Koetsier, M.
    van Oeveren, W.
    Lundberg, L.
    Assa, S.
    Franssen, C. F. M.
    Smit, A. J.
    Rakhorst, G.
    Sikole, A.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Ages in hemodialysis: tissue- and plasma- autofluorescence2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 606-606Article in journal (Other academic)
  • 7. Hadimeri, Ursula
    et al.
    Wärme, Anna
    Nasic, Salmir
    Fransson, Sven-Göran
    Wigelius, Ann
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Angiography and phlebography in a hemodialysis population: A retrospective analysis of interventional results2019In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040Article in journal (Refereed)
    Abstract [en]

    Objective: To clarify the reasons and beneficial effects and duration of arteriovenous fistula patency after radiological interventions in arteriovenous fistula. The patients investigated were referred due to arteriovenous fistula access flow problems.

    Material and methods: In 174 patients, 522 radiological investigations and endovascular treatments such as percutaneous transluminal angioplasty were analyzed, retrospectively. All investigations were performed due to clinical suspicion of impaired arteriovenous fistula function.

    Results: Arterial stenosis was significantly more frequent among patients with diabetic nephropathy (p < 0.001) and interstitial nephritis (p < 0.001). According to the venous stenosis, the diagnosis did not affect the frequency (p = 0.22) or the degree (p = 0.39) of stenosis. The degree of stenosis prior to percutaneous transluminal angioplasty correlated significantly with the degree of remaining stenosis after intervention (p < 0.001). Of the 174 patients, 123 (71%) performed a total of 318 investigations including percutaneous transluminal angioplasty. Repeated percutaneous transluminal angioplasty was performed significantly more often in patients with diabetic nephropathy. The median times to the first percutaneous transluminal angioplasty and to the subsequent percutaneous transluminal angioplasties were 9.5 and 5 months, respectively. Arteriovenous fistula in patients with diabetic nephropathy performed similar to most other diagnoses, although performing more percutaneous transluminal angioplasty/patient than most other diagnoses.

    Conclusion: Many patients could maintain long-term patency of arteriovenous fistula, including those with diabetic nephropathy, with repeated interventions; this motivates a closer follow-up for these patients. Clinically significant stenosis should be dilated as meticulously and as soon as possible. Occlusions of the arteriovenous fistula in most instances can be successfully thrombolyzed or dilated upon early diagnosis.

  • 8.
    Johagen, Daniel
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Svenmarker, Pontus
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Department of Biomedical Engineering and Informatics, Umeå University, Umeå, Sweden.
    Svenmarker, Staffan
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    A microscopic view of gaseous microbubbles passing a filter screen2017In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 40, no 9, p. 498-502Article in journal (Refereed)
    Abstract [en]

    Purpose: The aim of this study was to investigate the filtration efficacy of a 38-µm 1-layer screen filter based on Doppler registrations and video recordings of gaseous microbubbles (GME) observed in a microscope.

    Methods: The relative filtration efficacy (RFE) was calculated from 20 (n = 20) sequential bursts of air introduced into the Plasmodex® primed test circuit.

    Results: The main findings indicate that the RFE decreased (p = 0.00), with increasing flow rates (100-300 mL/min) through the filter screen. This reaction was most accentuated for GME below the size of 100 µm, where counts of GME paradoxically increased after filtration, indicating GME fragmentation. For GME sized between 100-250 µm, the RFE was constantly >60%, independently of the flow rate level. The video recording documenting the GME interactions with the screen filter confirmed the experimental findings.

    Conslusions: The 38-µm 1-layer screen filter investigated in this experimental setup was unable to trap gaseous microbubbles effectively, especially for GME below 100 µm in size and in conjunction with high flow rates.

  • 9.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Evaluation of air contamination incidences and in vitro settings and experiences of micro bubbles2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 636-636Article in journal (Other academic)
  • 10.
    Jonsson, Per
    et al.
    Department of Biomedical Engineering, University Hospital, Umeå, Sweden.
    Forsberg, Ulf
    Department of Internal Medicine, University Hospital, Umeå, Sweden.
    Niklasson, Johan
    Department of Internal Medicine, University Hospital, Umeå, Sweden.
    Stegmayr, Bernd G.
    Department of Internal Medicine, University Hospital, Umeå, Sweden.
    Electrical current leakage during hemodialysis may increase blood-membrane interaction2001In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 24, no 3, p. 136-139Article in journal (Refereed)
    Abstract [en]

    During hemodialysis blood - membrane interaction causes complement activation. During dialysis there may be an electrical current leakage to the dialyzer, especially if there is a broken ground or a defect in another electrical device coupled to the patient.

    This study investigated whether an electric current of 1.5 mA DC could alter blood membrane interaction as measured by changes in C3d in the blood. Such a high current leakage could occur because there is no protection in the dialysis machine (Class 1B) against auxiliary current leakage. Such a current could come from a defective external device in contact with the patient during hemodialysis.

    Materials: A dialysis machine (Fresenius 2008C) with a filled blood-line system containing about 350 ml whole blood from each of 8 different donors was used in vitro. Each of the eight test-runs also contained 1000 U added heparin. The dialysis procedure was performed using hemophan membranes (GFS +12, Gambro) with bicarbonate and potassium 3.0 (D210, Gambro) as dialysate. Two electric poles were placed in the blood line, before and after the dialyzer (connected in parallel) and the ground was placed at entry and exit of the dialysate fluid coming from the machine to the dialysis filter. C3d was measured before the start of “dialysis” and at 15, 30, 45 and 60 min, during dialysis. Thereafter the 1.5 mA current was switched on and additional samples were drawn at 75 and 90 min. The mean C3d values were calculated. Paired non-parametric statistical analyses were performed.

    Results: There was a significant and continuous increase in C3d as compared to the “predialysis” level. The increase during 0 to 30 minutes was greater than that from 30 to 60 minutes (p=0.018); the increase in C3d during 60 to 90 min, was greater than that from 30 to 60 min (p=0.018) and there was no difference between the 0 to 30 and the 60 to 90 min increases.

    Conclusions: A current, used in this study, was able to induce a blood membrane interaction during in vitro dialysis. Even a weaker current leakage might have such adverse effects and similar interactions seem possible during regular dialysis depending on the extent of the leakage.

  • 11.
    Kyrk, Tobias
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Bechara, Alex
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Skagerlind, Malin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Heparin and albumin as part of the priming solution limits exposure to anticoagulation during hemodialysis: in vitro studies2014In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 37, no 10, p. 734-740Article in journal (Refereed)
    Abstract [en]

    Background: Hemodialysis patients who are subject to increased risk of hemorrhage may need specific dialysis regimes to avoid bleeding. The aim of this study was to determine in vitro which of various anticoagulation options were most beneficial.

    Materials and method: 60 in vitro hemodialyses (HD) were performed in parallel using blood from healthy donors. The dialysis circuits were rinsed with either 1 L of 0.9% NaCl alone (n = 6), or with 1 L saline and the addition of either 5 mL 20% albumin (Alb, n = 6), 5,000 U of heparin (Hep, n = 6), Hep and Alb in combination (HA, n = 30), 20,000 U of Hep and Alb (4H-A, n = 6), and finally Hep and 20 mL 20% albumin (H-4A, n = 6). The blood was recirculated for a maximum of 192 min. Clotting was graded.

    Results: A 192 min dialysis was completed with all series of HA, 4H-A, and H-4A, all with a slight grade of clotting. In contrast to the above settings (p = 0.002, Fisher's test), a total clotting of the dialysis circuit occurred for all series using the NaCl rinsing alone (median time to stop: 21, range: 18-27 min, p = 0.026 compared to the HA setting) and for the Alb rinsing (median 26, range: 19-35 min, p = 0.028).

    Conclusions: Priming using HA, Hep, 4H-A, and H-4A reduced clotting and allowed 192 min of HD. Clinical studies need to confirm these data in vivo.

  • 12.
    Laveborn, Emilie
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lindmark, Krister
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Skagerlind, Malin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    NT-proBNP and troponin T levels differ after haemodialysis with a low versus high flux membrane2015In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 38, no 2, p. 69-75Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Brain natriuretic peptide (BNP), N-terminal-proBNP (NT-proBNP), and high sensitive cardiac troponin T (TnT) are markers that are elevated in chronic kidney disease and correlate with increased risk of mortality. Data are conflicting on the effect of biomarker levels by hemodialysis (HD).Our aim was to clarify to what extent HD with low-flux (LF) versus high-flux (HF) membranes affects the plasma levels of BNP, NT-proBNP, and TnT.

    METHODS AND MATERIALS: 31 HD patients were included in a crossover design, randomized to start dialysis with a LF-HD or HF-HD dialyzer. Each patient was his/her own control. The dialyses included in the study were the first treatments of two consecutive weeks with each mode of dialysis. Patients normally on hemodiafiltration (HDF) also performed a HDF the third week. Values after HD were corrected for extent of ultrafiltration.

    RESULTS: During LF-HD the biomarkers NT-proBNP and TnT increased (15 versus 6%, P ≤ .001) while there was a slight decrease in BNP (P<.05). During HF-HD the NT-proBNP, BNP and TnT levels decreased (P ≤ .01 for all). During HDF all three markers decreased (P<.01 for all). The rise in TnT during LF-HD correlated with dialysis vintage (months on HD, r = .407, P = .026), Kt/V-urea (r = .383, P = .037), HD time in hours/treatment (r = .447, P = .013) and inversely with residual urinary output (r = -.495, P = .005). The baseline levels of BNP and NT-proBNP correlated with blood pressure.

    CONCLUSIONS: Cardiac biomarkers increase slightly during LF-HD. A HF-HD eliminates the biomarkers and can mask increases caused by, e.g., myocardial infarction.

  • 13.
    Mahmood, Dana
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Makoveichuk, Elena
    Nilsson, Solveig
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Olivecrona, Gunilla
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Physiological chemistry.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Response of angiopoietin-like proteins 3 and 4 to haemodialysis2014In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 37, no 1, p. 13-20Article in journal (Refereed)
    Abstract [en]

    Background/Aim: Patients on chronic hemodialysis (cHD) have decreased activity of lipoprotein lipase (LPL). Angiopoietin-like proteins (ANGPTL) 3 and 4 have been shown to inactivate LPL. The aim of this study was to investigate the levels of the ANGPTLs in plasma of cHD-patients and to evaluate if cHD may alter these levels. Material and methods: Baseline data were collected from cHD patients (n = 23), and controls (n = 23) and samples were analyzed from 17 patients during low-flux or high-flux HD, and from ultrafiltrate (n = 5). The levels of ANGPTL3 and 4, LPL and triglycerides were studied in a cross-over design on cHD with local citrate compared to tinzaparin as anticoagulant. Results: The level of ANGPTL3 was higher than ANGPTL4 in patients and controls (p<0.01); the ANGPTL3 was 2.0 and ANGPTL4 was 3.3-fold higher in cHD versus controls. The levels of ANGPTL4 increased during cHD. After 180 min of HD the values had decreased again. When the dialysis was performed with high-flux filter, the mean level of ANGPTL4 at 180 min was below the value observed before cHD (p = 0.003). There was immunoreaction for ANGPTL4 in UFs when using high-flux, but not with low-flux, filter. ANGPTL3 was not detectable in UF. On cHD with citrate, no LPL activity was released into the blood. Conclusions: ANGPTL3 and ANGPTL4 were increased in HD patients. Anticoagulation with tinzaparin during cHD causes release of ANGPTL4 from tissues into blood. cHD using high-flux filters, to some extent, removed ANGPTL4. With citrate the levels of ANGPTL4 decreased.

  • 14. Polaschegg, H. D.
    et al.
    Stegmayr, B.
    Brännström, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Forsberg, U.
    Jonsson, P.
    Stegmayr, C.
    Hultdin, Johan
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Clinical chemistry.
    Microbubbles of air during hemodialysis: negligible for the patient?2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 654-654Article in journal (Refereed)
    Abstract [en]

    The symposium covers information about the presence of microbubbles in hemodialysis. Physical basis, technical considerations and regulations will be presented by Hans-Dietrich Polaschegg (Koestenberg, Austria). Per Jonsson (Umeå, Sweden) will cover experimental projects that were focused to evaluate the presence of microbubble air as contamination in the

    in vitro setting and some experiences. Those data and techniques were further used in in vitro testing of prevailing materials and basis for initial clinical studies on chronic hemodialysis sessions (Bernd Stegmayr, Umeå, Sweden). The symposium will thereafter focus on more clinical studies to investigate various clinical settings in relation to micro bubble exposure. This will be presented by Ulf Forsberg (Skellefteå, Sweden). The importance of microbubbles of air may be questioned. Therefore post mortem investigations were performed on hemodialysis patients. These data will be presented by Thomas Brännström (Umeå, Sweden). The symposium will end with time for discussion.

  • 15.
    Pulkkinen, Hertta
    et al.
    Institute of Biomedicine, Department of Anatomy, University of Kuopio, Kuopio, Finland; Department of Orthopaedics and Traumatology, Jyväskylä Central Hospital, Jyväskylä, Finland.
    Tiitu, Virpi
    Institute of Biomedicine, Department of Anatomy, University of Kuopio, Kuopio, Finland; Department of Orthopaedics and Traumatology, Jyväskylä Central Hospital, Jyväskylä, Finland.
    Valonen, Piia
    Institute of Biomedicine, Department of Anatomy, University of Kuopio, Kuopio, Finland; Department of Orthopaedics and Traumatology, Jyväskylä Central Hospital, Jyväskylä, Finland.
    Hämäläinen, Eija-Riitta
    Bioprocess Engineering Laboratory, University of Oulu, Oulu, Finland.
    Lammi, Mikko
    Institute of Biomedicine, Department of Anatomy, University of Kuopio, Kuopio, Finland; Department of Biosciences, Applied Biotechnology, University of Kuopio, Kuopio, Finland.
    Kiviranta, Ilkka
    Department of Orthopaedics and Traumatology, Jyväskylä Central Hospital, Jyväskylä, Finland; Department of Orthopaedics and Traumatology, Helsinki University Hospital, Helsinki, Finland.
    Recombinant human type II collagen as a material for cartilage tissue engineering.2008In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 31, no 11, p. 960-969, article id 19089798Article in journal (Refereed)
    Abstract [en]

    PURPOSE: Collagen type II is the major component of cartilage and would be an optimal scaffold material for reconstruction of injured cartilage tissue. In this study, the feasibility of recombinant human type II collagen gel as a 3-dimensional culture system for bovine chondrocytes was evaluated in vitro.

    METHODS: Bovine chondrocytes (4x106 cells) were seeded within collagen gels and cultivated for up to 4 weeks. The gels were investigated with confocal microscopy, histology, and biochemical assays.

    RESULTS: Confocal microscopy revealed that the cells maintained their viability during the entire cultivation period. The chondrocytes were evenly distributed inside the gels, and the number of cells and the amount of the extracellular matrix increased during cultivation. The chondrocytes maintained their round phenotype during the 4-week cultivation period. The glycosaminoglycan levels of the tissue increased during the experiment. The relative levels of aggrecan and type II collagen mRNA measured with realtime polymerase chain reaction (PCR) showed an increase at 1 week.

    CONCLUSION: Our results imply that recombinant human type II collagen is a promising biomaterial for cartilage tissue engineering, allowing homogeneous distribution in the gel and biosynthesis of extracellular matrix components.

  • 16.
    Ramsauer, Bernd
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Engels, Gerwin
    Arsov, Stefan
    Hadimeri, Henrik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Sikole, Aleksandar
    Graaff, Reindert
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Comparing changes in plasma and skin autofluorescence in low-flux versus high-flux hemodialysis2015In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 38, no 9, p. 488-493Article in journal (Refereed)
    Abstract [en]

    Background: Tissue advanced glycation end products (AGE) are increased in hemodialysis (HD) patients, especially those with cardiovascular complications. Skin autofluorescence (skin-AF) can noninvasively estimate the accumulation of AGE in tissue. The aim was to clarify whether HD using a high-flux (HF) dialyzer favors plasma-or skin-AF removal compared to low-flux (LF) dialysis. Material and methods: 28 patients were treated with either an HF-HD or LF-HD but otherwise unchanged conditions in a cross-over design. A glucose containing dialysate was used. Skin-AF was measured noninvasively with an AGE reader before and after HD. Fluorescence (370 nm/465 nm) of plasma (p-AF) was determined as total and nonprotein-bound fractions. Correction for hemoconcentrations were made using the change in serum albumin. Paired and nonpaired statistical analyses were used. Results: Skin-AF was unchanged after LF- and HF-dialysis. Total, free, and protein-bound p-AF was reduced after a single LF-HD by 21%, 28%, and 17%, respectively (P<.001). After HF HD total and free p-AF was reduced by 5% and 15%, respectively (P<.001), while protein bound values were unchanged. The LF-HD resulted in a more pronounced reduction of p-AF than did HF HD (P<.001). Serum albumin correlated inversely with p-AF in HF-HD. Conclusions: In the dialysis settings used there was no significant change in skin AF after dialysis, with LF or with HF dialysis. Although only limited reduction in plasma fluorescence was observed, this was more pronounced when performing LF dialysis. These data are not in overwhelming support of the use of HF dialysis in the setting used in this study.

  • 17. Sikole, A.
    et al.
    Trajceska, L.
    Arsov, S.
    Dzekova, P.
    Amitov, V.
    Selim, G.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Graff, R.
    Rakhorst, G.
    Does the advanced glycation end-products (ages) food intake influence mortality in dialysis patients?2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 606-606Article in journal (Other academic)
  • 18.
    Stegmayr, B. G.
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Forsberg, U.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, C. J.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, P.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    In vitro testing of prevailing materials and initial clinical findings2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 636-636Article in journal (Refereed)
    Abstract [en]

    Objectives: During HD previous studies have shown that especially micro bubbles of air may pass the air detector. These studies focused to analyse in vitro if the air trap of various producers may contribute to the presence of micro embolic counts in the fluid that has passed the air trap detector. In addition another in vitro study analysed if the dialyzer by itself may contribute to these contaminations. In parallel a clinical study was performed to evaluate if findings during in vitro tests could be found to some extent during chronic hemodialysis. If such contamination was present how frequent this would be and would it be a greater risk at the start or the end of dialysis.

    Methods: A ultrasound probe was placed on the venous dialysis tube after the air detector and venous chamber (Hatteland, Norway).

    Results:The studies verified previous in vitro studies with micro embolic counts that pass the air trap without inducing an alarm. Fewer embolic signals were detected in the in vitro studies when using a high level of the fluid in the air trap and when using a wet dialyzers. In the clinical studies high counts were present both at the first period as well as the last period of hemodialysis.

    Conclusions: These studies verify the finding of embolic counts in various extents in various in vitro settings, but also verify the presence of such counts in the dialysis tubes after the air trap in clinical routine hemodialysis. Further studies are warranted to clarify how to prevent patients from such problems and to clarify if the counts are clinically relevant.

  • 19.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Medicine.
    Abstracts of the XXXIV Annual ESAO (European Society for Artificial Organs) Congress, Krems, Austria, 3-5 September 2007.: World Apheresis Registry data 20052007In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 30, no 8, p. 689-748Article in journal (Refereed)
  • 20.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Presidential address: XLI Annual ESAO Congress - 17-20 September 2014, Rome, Italy2014In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 37, no 8, p. 569-Article in journal (Other academic)
  • 21.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    The use of citrate-containing dialysate for anticoagulation in hemodialysis (hd). report of clinical experience2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 629-629Article in journal (Other academic)
  • 22.
    Stegmayr, Bernd
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Brännström, M
    Bucht, S
    Dimeny, Emöke
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Ekspong, A
    Granroth, B
    Gröntoft, KC
    Hadimeri, H
    Holmberg, Benny
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Ingman, B
    Isaksson, B
    Johansson, G
    Lindberger, K
    Lundberg, Lennart
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lundström, Ola
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Mikaelsson, L
    Mörtzell, Monica
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Olausson, E
    Persson, B
    Svensson, L
    Wikdahl, AM
    Minimized weight gain between hemodialysis contributes to a reduced risk of death2006In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 29, no 7, p. 675-680Article in journal (Refereed)
  • 23.
    Stegmayr, Bernd
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Mahmood, Dana
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    A significant proportion of patients treated with citrate containing dialysate need additional anticoagulation2013In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 36, no 1, p. 1-6Article in journal (Refereed)
    Abstract [en]

    Background: The blood membrane interaction induced during hemodialysis (HD) activates the coagulation system. To prevent clotting and to maintain dialyzer patency, an anticoagulant such as tinzaparin is used. To increase patency of the dialyzers and to reduce the risk of bleeding related to anticoagulation, citrate-containing dialysate has been introduced in Europe.

    Purpose: The aim of this randomized, cross-over study was to investigate if citrate-containing dialysate was safe and efficient enough as the sole anticoagulation agent in chronic HD patients.

    Material and Methods: In this clinical setting, 23 patients on chronic hemodialysis were randomized in a cross-over design using anticoagulation either by LMWH-tinzaparin or citrate (Cit) as dialysate (22 completed the study). The study included paired analyses of subjective patency, ionized calcium (iCa), urea reduction rate. During Cit-HD, the iCa was significantly more reduced with prolonged time. The lowest iCa measured was 0.96 mmol/l. The median iCa after 210 min of HD was 1.02 for Cit-Hd and 1.16 for standard tinzaparin-HD (p = 0.001). Patency of dialyzers was estimated as clear in 14%, stripes of clotted fibers in 36%, and a red filter in 32% of HD session. The addition of approximately 40% of the patients’ usual dose of tinzaparin was given to 7 of the patients as a bolus. Four Cit-HD sessions had to be interrupted prematurely due to clotting.

    Conclusion: A significant proportion of patients treated with citrate-containing dialysate need additional anticoagulation.

  • 24.
    Stegmayr, Bernd
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Klinkmann, Horst
    Dieter Falkenhagen (1942-2015): a multifaceted scientist2015In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 38, no 11, p. 617-623Article, review/survey (Refereed)
    Abstract [en]

    Dieter Falkenhagen was born in 1942 in Dresden, Germany and died in 2015. He specialized in internal medicine and nephrology. Focusing on artificial organ research, he investigated various aspects of the efficacy and safety of hemodialysis and adsorption technologies, including biocompatibility issues related to blood versus surface interactions and the adverse effects of endotoxin contamination. He studied various mathematical models to analyze efficacy and safety, and animal models to help clarify uncertainty issues. Through his studies, adsorbents were developed, resulting in Prometheus, an artificial liver support device. Anticoagulation models, including citrate perfusion, were improved and made safer by his work. He also stepped into bioreactor research to increase efficacy of liver support devices.

  • 25.
    Stegmayr, Bernd
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Ptak, J
    Wikström, B
    World apheresis registry2004In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 27, no 7, p. 589-Article in journal (Refereed)
  • 26.
    Stegmayr, Bernd
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Raumsaur, B.
    Arsov, S.
    Lundberg, Lennart
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Rakhorst, G.
    Sikole, A.
    Graaff, R.
    How can we optimize hemodialysis to prevent from ages2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 607-607Article in journal (Other academic)
  • 27.
    Stegmayr, Christoffer
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Forsberg, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Hemodialysis dialyzers contribute to contamination of air microemboli that bypass the alarm system in the air trap.2008In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 31, no 4, p. 317-22Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Previous studies have shown that micrometer-sized air bubbles are introduced into the patient during hemodialysis. The aim of this study was to investigate, in vitro, the influence of dialysis filters on the generation of air bubbles. METHODS: Three different kind of dialyzers were tested: one high-flux FX80 dry filter (Fresenius Medical Care AG&Co. KGaA, Bad Homburg, Germany), one low-flux F8HPS dry filter (Fresenius Medical Care AG&Co. KGaA, Bad Homburg, Germany) and a wet-stored APS-18u filter (Asahi Kasei Medical, Tokyo, Japan). The F8HPS was tested with pump flow ranging between 100 to 400 ml/min. The three filters were compared using a constant pump flow of 300 ml/min. Measurements were performed using an ultrasound Doppler instrument. RESULTS: In 90% of the series, bubbles were measured after the outlet line of the air trap without triggering an alarm. There were significantly more bubbles downstream than upstream of the filters F8HPS and FX80, while there was a significant reduction using the APS-18u. There was no reduction in the number of bubbles after passage through the air trap versus before the air trap (after the dialyzer). Increased priming volume reduced the extent of bubbles in the system. CONCLUSIONS: Data indicate that the air trap does not prevent air microemboli from entering the venous outlet part of the dialysis tubing (entry to the patient). More extended priming of the dialysis circuit may reduce the extent of microemboli that originate from dialysis filters. A wet filter may be favorable instead of dry-steam sterilized filters.

  • 28. Trajceska, L.
    et al.
    Arsov, S.
    Graaff, R.
    Oeveren, W.
    Smit, A. J.
    Dzekova, P.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Sikole, A.
    Rakhorst, G.
    Skin af and food, is there any relation?2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 8, p. 606-606Article in journal (Other academic)
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