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Biomedical subjects

K Era

Publications and source records attributed to K Era.

23 records · Page 2Linked to original sources

Development of continuous recirculating peritoneal dialysis using a double lumen catheter.

Continuous recirculating peritoneal dialysis (CRPD) was newly introduced to improve solute removal efficiency in conventional dialysis therapies such as hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD). In CRPD, a part of the dialysate in the peritoneal cavity was drained through a double-lumen catheter and purified by an extracorporeal dialyzer. Urea removal characteristics in CRPD were examined in a canine study. In this study, a recirculation-dialysis experiment using a dog weighing 9.0 kg was carried out under 100 and 200 ml/min of flow for recirculating and delivered dialysates, respectively. An FB-50H (Nipro Medical Industries, Ltd., Osaka, Japan) composed of cellulose diacetate membrane with 0.5 m2 of surface area and Dianeal-1.5 (Baxter Limited Laboratories, Tokyo, Japan) containing urea were used as the extracorporeal dialyzer and dialysate. Urea peritoneal and dialyzer dialysances (DBP and DBD) were 3.05 and 33.3 ml/min by computer simulation using a compartment model for CRPD. This DBP value can be estimated as 20.3 ml/min for a 60 kg human. From this result, time-averaged value for BUN over an 8 hr/day CRPD, combined with three exchanges/day as CAPD is estimated to be 34.3 mg/dl, which is much lower than 45.2 mg/dl for a 12 hr/week HD, or 53.0 mg/dl for conventional CAPD.

Animals↗

Non-heparin hemodialysis with oral administration of newly developed antiplatelet agent.

Non-heparin hemodialysis (HD) was successfully done in anuric dogs with the oral administration of a newly developed antiplatelet agent, 4-cyano-5,5-bis(4-methoxyphenyl)-4-pentenoic acid, (E5510, Eisai Pharmaceutical Co., Japan). In the current study, the antithrombotic effect of E5510 during HD was investigated. Eleven mongrel dogs with bilateral ureteral ligation were given 0.1 mg/kg of E5510 orally 1 hr before undergoing 4 hr HD using hollow fiber dialyzers, (PMMA 5, regenerated cellulose 6) without heparin and under general anesthesia. Blood samples were taken before the administration of E5510 and before and 1, 2, 3, and 4 hr after starting HD; blood counts, hematocrits, blood chemistries, and plasma thromboxane levels (TxB2) were examined. Platelet aggregation, activated clotting times (ACT), and activated partial thrombin times (APTT) were also measured, and sequential plasma E5510 concentrations were determined. In 10 of 11 anuric dogs, non-heparin HD was successfully done with minimal clotting in the dialyzer and drip chambers. The maximum aggregation rate was depressed to less than 20% of the initial value throughout HD. Plasma TxB2 concentration was depressed, and ACT and APTT were mildly, but not significantly prolonged. Neither hemorrhagic complications nor other side effects of E5510 were observed.

Administration, Oral↗

Difference in beta 2-microglobulin removal between cellulosic and synthetic polymer membrane dialyzers.

Several kinds of dialyzers, with highly permeable membranes (HPM), have been designed to specifically remove beta 2-microglobulin (BMG). To clarify their solute transport characteristics, nine types of HPM dialyzers were evaluated during in vivo and in vitro studies using human plasma and aqueous solutions. No BMG membrane adsorption and/or plugging was seen with cellulosic membrane dialyzers during in vitro experiments using human plasma. On the other hand, all synthetic polymer membrane dialyzers had adsorptive properties, and in a dialyzer with a polymethylmethacrylate membrane, a large amount of BMG was removed by adsorption alone. Dialyzers with cellulose triacetate and polyacrylonitril membranes showed higher values of BMG diffusive dialysance (greater than 20 ml/min) and sieving coefficient (greater than 0.9). From in vitro experiments using an aqueous solution containing several solutes with relatively small or middle molecular weights, all HPM dialyzers had a higher overall mass transfer coefficient than any conventional membrane dialyzer.

Blood Flow Velocity↗

Changes in electrical charge of leukocyte surface membranes during hemodialysis. Possible role in transient leukopenia.

Change in the electrical charge of leukocyte surface membranes during hemodialysis (HD) using a cellulose membrane was studied by examining adsorbability of leukocytes taken from patients undergoing HD to cation and anion exchange resins. Leukocytes of HD patients were well adsorbed to both anion and cation exchange resins, whereas normal leukocytes were only minimally adsorbed to a cation exchange resin, suggesting that the surface membranes of normal leukocytes were charged electronegatively. Adsorbability to anion exchange resin by patients' leukocytes taken from the venous limb of the HD circuit line 15 minutes after starting HD was significantly decreased when using a cellulosic membrane. This suggests that the decrease in electronegative leukocyte surface membrane charge, which may facilitate the attachment of leukocytes to electronegatively charged endothelial cell membranes, is the factor leading to leukopenia. Adsorbability to anion exchange resin by normal leukocytes incubated with plasma taken from HD patients 10 to 60 minutes after starting HD was increased, suggesting an increase in electronegatively charged substances in patients' plasma; these recombine with leukocyte surface membranes thereby increasing the electronegative charges of the leukocyte surface membranes and enabling subsequent release of leukocytes from endothelial cells, consistent with the transient nature of the leukopenia.

Adsorption↗