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Biomedical subjects

T Akizawa

Publications and source records attributed to T Akizawa.

124 records · Page 7Linked to original sources
PubMed1981

Plasma beta-thromboglobulin levels in chronic renal failure patients.

Impaired platelet function is commonly recognized in uremia. It is partially improved by dialysis. However, in regular hemodialysis patients (RD), platelet function is not fully evaluated. This study investigated platelet activity in chronic renal failure (CRF) using beta-thromboglobulin (BTG) as a marker. BTG in RD were significantly higher than those in non-dialyzed CRF patients (P less than 0.05), and BTG in non-dialyzed CRF were higher than in normal controls (P less than 0.01). In non-dialyzed CRF, BTG were correlated to serum creatinine value (P less than 0.01). Arteriovenous fistula did not affect BTG. Hemodialysis and direct hemoperfusion with charcoal beads increased BTG but neither peritoneal dialysis nor hemofiltration altered BTG. RD treated over one year showed higher BTG than those treated for less than one year (P less than 0.01). In RD who showed elevated BTG, platelet aggregation and retention rates were depressed and bleeding times were prolonged. These results indicate that BTG can be used as the marker of impaired platelet function in CRF and of the blood compatibility of artificial kidneys.

Beta-Globulins↗
PubMedDate not supplied

Efficiency and biocompatibility of a polyethylene glycol grafted cellulosic membrane during hemodialysis.

Dialytic efficiency and biocompatibility of a new modified cellulose membrane (NMC) were examined in vitro and clinically. NMC was obtained by grafting polyethylene-glycol (PEG) chains to the membrane surface of ordinary cellulose (OC), and it was expected that the random movement of PEG chains would prevent blood cells and large plasma proteins from coming into contact with the membrane surface, resulting in improving the biocompatibility and thrombogenicity of the membrane. Surface characteristics of NMC were rendered anionic and hydrophilic, however, the activations of complement and platelet systems were clearly suppressed in NMC. Minimum heparin requirement for hemodialysis was significantly lower with NMC than with OC dialyzer. No significant difference in solute and water removal was observed between the two dialyzers. These results indicate that NMC can provide increased biocompatibility and antithrombogenic effect while retaining the essential dialysis efficiency of OC.

Biocompatible Materials↗
PubMedDate not supplied

Development of a new cellulose triacetate membrane with a microgradient porous structure for hemodialysis.

Dialytic performance and biocompatibility of a newly developed cellulose triacetate (CTA) membrane with a microgradient porous structure, produced without using polyvinylpyrrolidone (PVP) and liquid paraffin, were compared with those of a conventional polysulfone (PS) membrane dialyzer. In vitro and clinical results demonstrated no significant difference in the dialytic performance and biocompatibility of the two dialyzers, but the CTA dialyzer lost less albumin during dialysis than the PS. These results suggest that a CTA membrane dialyzer with a porous microgradient structure attained comparable performance and biocompatibility to PS, and the risk of albumin loss was suppressed by the new CTA membrane.

Cellulose↗
PubMedDate not supplied

Endothelin and platelet activating factor. Possible indices for biocompatibility of hemodialysis.

To clarify the roles of endothelin (ET: vasoconstrictor) and platelet activating factor (PAF: vasodilator) in hemodialysis (HD), intradialytic changes in those substances were compared by a crossover study between HD with regenerated cellulose (RC) and polymethylmethacrylate (PMMA) membranes using currently developed radioimmunoassay methods. Hemodialysis patients demonstrated higher plasma ET values than normal controls, and hypertensive HD cases showed the highest levels. Although ET decreased significantly during the initial stage of HD with both membranes, the decreasing rates were greater in the group with intradialytic hypotension than those in the normotensive group. Plasma PAF did not differ among normal controls, hypertensive HD, and normotensive HD patients. Platelet activating factor tended to increase during HD in both hypotensive and normotensive groups; however, the increasing rates were greater in HD with RC than those with PMMA. These results indicate that the decrease in ET may partially contribute to the initiation of HD induced hypotension. Because PAF is an intracellular mediator, and there is an intradialytic increase in PAF with RC membrane, PAF should be regarded as one of the indices of membrane biocompatibility.

Adult↗
PubMedDate not supplied

Changes in endothelial vasoactive substances under recombinant human erythropoietin therapy in hemodialysis patients.

The effects of recombinant human erythropoietin (rHuEPO) on endothelial vasoactive substances were evaluated in 19 regular hemodialysis patients. Blood cell counts, plasma endothelin (ET), alpha-human atrial natriuretic peptide (ANP), platelet activating factor (PAF), 6-keto-prostaglandin F1 alpha (PGF1 alpha), and 11-dehydro-thromboxane B2 (TXB2) were evaluated before rHuEPO treatment; at 4, 8, and 12 weeks during treatment; and 5 weeks after the end of treatment. PAF and TXB2 remained unchanged during the study period, PGF1 alpha and ET significantly increased, and ANP decreased along with an improvement in the anemia. Since endothelial vasoactive substances changed significantly during rHuEPO therapy, the correction of anemia with rHuEPO may affect endothelium.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Clinical effects of a polyethylene glycol grafted cellulose membrane on thrombogenicity and biocompatibility during hemodialysis.

The biocompatibility and thrombogenicity of polyethylene-glycol (PEG)-grafted cellulose hemodialysis (HD) membranes (PEGC) were investigated in cross-over HD of five HD patients with ordinary cellulose (OC). The PEGC significantly suppressed transient leukocyte and thrombocytopenia, and release of C3a, beta-thromboglobulin and platelet factor 4, in corresponding with the quantity of grafted PEG. HD with PEGC resulted in lower granulocyte elastase production, protein and blood cells adsorption on the membrane surface than those with OC. Minimum heparin in HD with PEGC was three times lower than that with OC, with the thrombin-antithrombin III complex elevation lower than that in HD with OC. The results indicate that the grafted PEG effectively suppresses blood and membrane interaction, thus improving biocompatibility and reducing thrombogenicity in clinical HD.

Biocompatible Materials↗
PubMedDate not supplied

Comparative clinical trial of regional anticoagulation for hemodialysis.

The regional anticoagulating effects of FUT-175 (protease inhibitor), and regional or low dose heparinization (RH or LH) were examined comparatively by randomized controlled protocol on 157 hemodialysis (HD) patients with hemorrhagic complications. Increases in bleeding because of HD were milder in FUT as compared with RH and LH, and the bleeding time after needle removal was significantly shorter in FUT than that in heparin. During HD, the prolongation of celite activated coagulation time (CCT) of the intracorporeal blood was significantly milder in FUT than in heparin and that of blood passing through the dialyzer was increased in FUT compared with LH. FUT showed no prolongation of CCT after HD. These results indicate that FUT is a more useful and safer anticoagulant for HD patients with hemorrhagic complications than any regional anticoagulating method using heparin (RH or LH).

Anticoagulants↗
PubMedDate not supplied

Development of a regenerated cellulose non-complement activating membrane for hemodialysis.

We have developed a new cellulose membrane in which the active hydroxyl and carboxyl groups of the original cellulose fibers are masked with cationic synthetic polymers. The membrane was shown by in vitro and clinical tests to affect the activation of the complement system very little, and it retains the high dialysis efficiency, good tolerance to steam autoclave sterilization, and economical production cost characteristics of the original cellulose membrane. It thus appears that the new cellulose provides the optimum combination of qualities needed in a hemodialysis membrane.

Cellulose↗