Biomedical subjects
Masamiki Miwa
Publications and source records attributed to Masamiki Miwa.
A timesaving method to create a fixed puncture route for the buttonhole technique.
BACKGROUND: Up to now, for a successful buttonhole puncture of the vascular access vessel, the fistula should be punctured by the same experienced medical staff for 2-3 months, using sharp needles, until a fixed puncture route is established. METHODS: We developed a timesaving method to create the fixed puncture route for the buttonhole technique. In this method, after the usual haemodialysis (HD), a newly developed thumbtack-shaped polycarbonate peg is thrust toward the access vessel along the same path as the puncture needle that has just been removed. Then, at the beginning of the next HD, the peg is removed and a dull puncture needle is inserted along the track already formed by the peg left in place. These steps are repeated at each HD session for 14 days. Thereafter, the vascular access is achieved at HD sessions by inserting a dull puncture needle through the established puncture route. RESULTS: This buttonhole puncture approach was used in 37 patients for 3 months. While the polycarbonate peg was in place, patients experienced no restrictions in their normal activities of daily living, except during bathing and showering. As for puncture pain, no patient found the pain of the buttonhole technique to be greater than that of the conventional puncture technique. Moreover, no significant bleeding was noted during HD. With this buttonhole puncture approach, only one patient had enough erythema at the puncture site to suggest possible infection. After HD, the time for bleeding to stop was <10 min in 95% of patients. CONCLUSION: This study showed the new timesaving method for creating a buttonhole to be safe and useful.
Changes in Mac-1 and CD14 expression on monocytes and serum soluble CD14 level during push/pull hemodiafiltration.
BACKGROUND/AIM: Employment of treated dialysate as replacement fluid raises concerns about exposure of patients to pyrogenic substances. This study was undertaken to evaluate the safety of treated dialysate as the replacement fluid for push/pull hemodiafiltration. METHODS: In the present study, changes in the expressions of Mac-1 and CD14 on monocytes, which are upregulated by monocyte activation, were analyzed by flow cytometry, and the serum level of sCD14 which elevates by monocyte activation was measured by enzyme-linked immunosorbent assay (ELISA) during treatment in 7 patients on hemodialysis with regenerated cellulose (RC) membrane, polysulfone (PS) membranes and by push/pull hemodiafiltration (HDF) with PS membranes in a cross-over fashion. RESULTS: During hemodialysis with RC, hemodialysis with PS or push/pull hemodiafiltration with PS, both Mac-1 and CD14 expressions on monocytes significantly increased by passing through the artificial kidneys, and, accordingly, the respective values downstream of the artificial kidneys were significantly higher than the predialysis values, even when the lipopolysaccharide level in dialysate was not detectable by Limulus assay. There was no significant variation in serum sCD14 levels during any of the hemodialysis with RC, hemodialysis with PS or push/pull hemodiafiltration. However, during hemodialysis with PS or push/pull hemodiafiltration with PS, changes in Mac-1 and CD14 expression on monocytes were significantly smaller than those during hemodialysis with RC. CONCLUSION: Monocytes are activated to a greater extent during hemodialysis with RC membranes than during push/pull HDF with PS membranes. We consider that push/pull HDF may be safer than hemodialysis with RC membrane and that it is as safe as hemodialysis with the PS membrane in terms of monocyte activation, when pyrogen-free dialysate is employed.
Platelet GPIIb/IIIa is activated and platelet-leukocyte coaggregates formed in vivo during hemodialysis.
BACKGROUND/AIM: During hemodialysis, platelets and leukocytes are activated and form platelet-leukocyte coaggregates in which GPIIb/IIIa (CD41/CD61) and CD62P (P-selectin) are involved. However, it is still controversial whether platelet activation and platelet-leukocyte coaggregate formation are dependent on the dialyzer membrane material. METHOD: We examined the appearance of activation-dependent antibody on platelets as an index of platelet activation, and the appearance of platelet-specific antigen on leukocytes as an index of platelet-leukocyte coaggregation, during hemodialysis in 7 patients treated using regenerated cellulose (RC) membrane and next using polysulfone (PS) membrane. In order to reduce the influence of factors other than dialyzer membrane material, this study was conducted in a prospective crossover fashion using a pyrogen-free bicarbonate dialysate. Moreover, flow cytometric techniques with whole blood were employed, which reduce artificial cell activation during the cell or plasma separation procedure. The platelet-specific monoclonal antibodies used in this study were anti-CD61, PAC-1 (which recognizes only the conformationally activated GPIIb/IIIa) and anti-CD62P. RESULTS: Changes in the percentage of PAC-1-positive platelets were significantly greater during hemodialysis with RC than with PS. However, changes in the percentage of CD62P-positive platelets were not significantly different between hemodialysis with RC and PS. Changes in the percentage of CD61- or CD62P-positive leukocytes were significantly greater during hemodialysis with RC than with PS. Although changes in percentage of PAC-1-positive platelets did not parallel those of CD62P-positive platelets during hemodialysis, there was a significant positive correlation between the percentage of CD61-positive leukocytes and the percentage of CD62P-positive leukocytes. CONCLUSION: This study, conducted in a prospective crossover fashion using a pyrogen-free bicarbonate dialysate in order to reduce the influence of factors other than the dialyzer membrane material, demonstrated that both the degrees of GPIIb/IIIa activation and platelet-leukocyte coaggregation were greater during hemodialysis with RC than PS.
Which Kt/V is the most valid for assessment of both long mild and short intensive hemodialyses?
It is unclear at present which mathematical modeling Kt/V(urea) is valid for assessment of both long mild hemodialysis (HD) and short intensive HD, the single-pool modeling Kt/V (Kt/Vsp) based on the pre- and postdialysis serum urea concentrations, double-pool modeling Kt/V (Kt/Vdp) based on the predialysis concentration and the estimated postdialysis equilibrated concentration, or Kt/V calculated on the basis of dialyzer urea clearance, HD session duration and urea distribution volume (Kt/Vdl). Thus, the respective Kt/V during a short intensive HD was compared with its counterpart Kt/V during a long mild HD, where the same amount of urea is removed during both HD treatments. It was found that the Kt/Vsp and Kt/Vdl during short intensive HD were significantly greater than the respective Kt/V during the long mild HD. On the other hand, there was no significant difference in the Kt/Vdp between the long mild and short intensive HDs. In conclusion, Kt/Vdp may be more valid for assessment of both long mild and short intensive HDs.