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- Alquist, M, et al.
(author)
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Development of a urea concentration gradient between muscle interstitium and plasma during hemodialysis
- 1999
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In: The International journal of artificial organs. - : SAGE Publications. - 0391-3988 .- 1724-6040. ; 22:12, s. 811-815
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Journal article (peer-reviewed)abstract
- In this pilot study, muscle interstitial urea concentrations during hemodialysis (HD) were determined with a microdialysis technique and the results were compared with plasma water urea concentrations. Three patients were investigated during a total of five treatments. Under predialysis steady-state conditions, no difference was observed. During treatment, the muscle interstitial urea concentration was on average 19% higher (range 13–28%, n=4) than the plasma urea concentration after 17±3 min, 29% higher (25–31%, n=3) after 53±10 min, 40% higher (26–50%, n=3) after 117±6 min, 31% higher (26–34%, n= 3) after 179±5 min, and 31% higher (27–36%, n=4) after 231±5 min. The gradient declined after the conclusion of HD, muscle interstitial concentrations being on average 16% (9–26%, n=4) higher than plasma urea concentrations 9±2 min after treatment, and 8% (6–10%, n=3) 25±3 min after treatment. Thus, a urea concentration gradient with a higher concentration in muscle interstitium than in plasma, developed during HD, and dissipated gradually after treatment. This is consistent with blood flow-dependent urea sequestration in muscle tissue, causing intercompartment disequilibrium of urea during HD, and its consequent redistribution after treatment contributing to postdialysis urea rebound.
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| 2. |
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| 3. |
- Lindström, Veronica, et al.
(author)
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Different elimination patterns of beta-trace protein, beta(2)-microglobulin and cystatin C in haemodialysis, haemodiafiltration and haemofiltration.
- 2008
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In: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 68, s. 685-691
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Journal article (peer-reviewed)abstract
- Objective. Low molecular mass proteins (LMMP) are putative uraemic toxins, but their elimination is negligible in standard haemodialysis (HD). In this study, we used beta(2)-microglobulin, cystatin C and beta-trace protein, which differ in molecular mass and charge, to characterize the elimination patterns of three different dialysis modalities. Material and methods. Plasma samples were obtained at the start, 30 min after the start, at the end of the dialysis treatment and 30 min after termination of the dialysis session. Seventeen patients were treated with low-flux HD, 13 with post-dilution haemodiafiltration (HDF) and 8 with pre-dilution haemofiltration (HF). The changes in concentrations of the three LMMPs were monitored and expressed as percentages of the concentrations at the start of treatments. Results. Conventional HD with low-flux membranes showed a high elimination of small molecules (urea and creatinine), but did not reduce the levels of the three LMMPs studied. During HDF and HF, there was a significant decrease in the plasma levels of cystatin C (to 28 % and 44 %, respectively) (p<0.001) and of beta(2)-microglobulin (to 23 % and 33 %, respectively) (p<0.001). However, the level of beta-trace protein was significantly reduced (to 65 %) only after HDF. Conclusions . The three dialysis modalities showed significantly different elimination patterns for the LMMPs studied. Elimination of beta-trace protein was lower than those of cystatin C and beta(2)-microglobulin both in HDF and HF. beta-trace protein was only moderately eliminated by HDF and not at all by HF, and may be a useful marker in the evaluation of different convective therapies.
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