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C Woffindin

Publications and source records attributed to C Woffindin.

26 records · Page 2Linked to original sources
PubMed1986

Complement activation in haemodialysis: a comparison of new and re-used dialysers.

The magnitude of leucopenia and complement activation when reusing cellulose based (Cuprophan) and synthetic (polyacrylonitrile AN-69S) haemodialysis membranes as well as their modifications by the priming of the dialysers with fresh frozen plasma and by the introduction of a period of stagnation during haemodialysis were studied using radioimmunoassay (C3a), centrifugal analysis (C3d), immunochemical (C3, Factor B) and functional (CH50 and alternate pathway) assays. Our findings demonstrate that complement activation and leucopenia induced by Cuprophan are linked and are modified when the membrane is reused, or primed with plasma protein. However, chemical exposure during reuse to sodium hypochlorite modifies these observations. Reuse of the AN-69S membrane resulted in no modification of either leucopenia or complement activity, but this membrane consistently demonstrated lower levels of C3a than observed with either first use or reused Cuprophan membranes.

Acrylic Resins↗
PubMed1985

A clinical appraisal and comparison of double pump single needle dialysis systems.

Six recently developed double pump tidal flow single needle systems have been assessed clinically and the magnitude of recirculation, efficiency of dialysis determined and compared with the classical system (Bellco BL 760). Results indicate that the problems of designing twin pump systems with instantaneous response, occlusive rollers capable of generating clinically acceptable blood flow rates has been largely overcome and such systems offer a high degree of patient acceptance, flexibility, safety and an efficiency of dialysis comparable with that obtained using two needle access.

Blood Flow Velocity↗
PubMed1985

Some aspects of residual formaldehyde testing when reusing haemodialysers.

To assess the adequacy of quantifying residual formaldehyde concentrations when reusing, four semi quantitative methods of concentration estimation (Clinitest tablets, Schiff's reagent, Formalert Formotest) were compared. Two of these methods (Schiff's reagent and Clinitest) were inadequate in detecting low concentrations of formaldehyde and were associated with false positives from interference by chemicals contained in the dialysate. When using the two reagents specifically manufactured for this purpose, we also observed false positives with one (Formotest) while the other was capable of detecting formaldehyde concentrations as low as 4.5 mg/l. To minimise patients' exposure and the formation of anti-N like antibodies resulting from formaldehyde damage of red cells, it would be prudent when reusing, to select the most sensitive of these semi-quantitative techniques for routine use, to perform regular screening for anti-N antibodies and to periodically check formaldehyde levels by the use of the highly specific Hantzsch reaction.

Formaldehyde↗
PubMed1983

Dialysis leucopenia--no correction after prolonged washing of the membrane.

Re-use of hemodialysers diminishes the extent of leucopenia observed during hemodialysis. A possible cause of this change is the prolonged washing of the membrane by an aqueous solution on both sides and by protein contained solutions on the blood side which removes some substance from the membrane which affects leucocytes directly or by activation of complement. A series of studies to test this hypothesis were performed using two hemodialysis membranes -Cuprophan (Enka AG) and Cellulate (Cordis Dow Corporation) and the results obtained demonstrate no elution of any water soluble substance from the dialyser membrane.

Humans↗
PubMed1983

The effect of hematocrit on the clearance of small molecules during hemodialysis.

Data collected during the evaluation of a series of hemodialysers were analysed to see the effect of hematocrit on the clearance of urea and creatinine. All evaluations were performed on patients with a range of hematocrits with a mean close to 20%. The urea clearance of those in the upper half of the distribution curve (mean hematocrit 29.4%) was not significantly different from that of patients in the lower half of the distribution curve (mean hematocrit 16.9%) whether the clearance was studied at high or low blood flow rates and with hollow fibre or flat plate disposable hemodialysers. Likewise, there was no correlation between hematocrit and urea clearance by regression analysis. In contrast, the clearance of creatinine was affected by hematocrit being greater at lower hematocrit values. This difference was independent of blood flow rate and dialyser type and was confirmed by regression analysis.

Creatinine↗