atsushi ohashi

Abstract Introduction Indoxyl sulfate (IS) is a protein‐bound uremic toxin that causes uremic sarcopenia. IS has poor dialysis clearance; however, the addition of a binding competitor improves its removal efficiency. Methods Dialysis experiments were performed using N‐acetyl‐l‐tryptophan (L‐NAT) instead of l‐tryptophan (Trp) using pooled sera obtained from dialysis patients. The molecular structures of L‐NAT and Trp were similar to that of IS. Therefore, we examined whether Trp and L‐NAT were involved in muscle atrophy in the same manner as IS by performing culture experiments using a human myotube cell line. Results The removal efficiency of L‐NAT was the same as that of Trp. However, L‐NAT concentrations in the pooled sera increased at the end of the experiment. Trp (1 mM) decreased the area of human myocytes, similar to IS, whereas L‐NAT did not. Conclusion L‐NAT is a binding competitor with the ability to remove protein‐bound IS while preventing sarcopenia.

Cell-free and concentrated ascites reinfusion therapy (CART) is performed by collecting the ascites from the patient, followed by filtration and concentration. Thereafter, concentrated cell-free ascites is reinfused into the patient intravenously. The new type of machine, Plasauto μ, for managing the process of CART was launched onto the market. We have evaluated the machine through postmarketing clinical study in 17 patients with malignant ascites. The amounts of original and concentrated ascites were 3673 ± 1920 g and 439 ± 228 g, respectively. Recovery rates were acceptable regarding values of total protein, albumin, and IgG that were 55.6% ± 17.3%, 60.2% ± 20.8%, and 58.2% ± 20.5%, respectively. Recovery rates were positively associated with amounts of original ascites and negatively associated with total protein concentration. No adverse events related to the machine were observed. The new type of machine showed preferable performance in processing malignant ascites.

Cell-free and concentrated ascites reinfusion therapy (CART) by internal filtration pressure method (internal method) and external filtration pressure method (external method) using the same cancerous ascites was performed. The rate of rise in circuit pressure and recovered components were compared between the two methods. The factors related to circuit pressure rise were also researched. In both methods, circuit pressure rose in 50% of cases. The recovery rates of IgG, IgA, IgM, and haptoglobin were significantly higher for the internal method than for the external method, whereas the recovery rate of α1 -antitrypsin was significantly lower in the internal method than in the external method. The levels of IL-6, haptoglobin, α1 -antitrypsin, and fibrinogen/fibrindegradation products (FDP) in the original ascites were significantly higher in the group wherein circuit pressure rose than in that without circuit pressure rise. These proteins might be related to the rise in circuit pressure.

Silver is used in various fields because of its high safety and broad antimicrobial spectrum. Here, the bactericidal activities of silver ion (Ag⁺) solution were compared to those of sodium hypochlorite (NaClO) in order to determine its usefulness as a disinfectant in hemodialysis. The minimum killing concentration (MKC) of each disinfectant was measured using the bacterial strains Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. With bacteria isolated from product water manufacturing processes (tap water, activated carbon filter treatment water, and RO water) and the dialysis fluid line (B tank and dialysis fluid), antibacterial tests were conducted using each disinfectant. In terms of MKC, while Ag⁺ solution was not as fast acting as NaClO, comparable bactericidal activities were observed over time. In particular, Ag⁺ solution appears to be more effective than NaClO in disinfecting chlorine-resistant water-borne bacteria inside the product water manufacturing line. In addition, Ag⁺ solution killed not only Gram-negative bacteria, but also Gram-positive bacteria. Thus, Ag⁺ solution may be used as a disinfectant in hemodialysis and it appears to be as useful as NaClO.

Anticoagulant free hemodialysis (HD), without complications, was possible with selection of an antithrombogenic membrane material and improvement of HD lines.<br>We performed anticoagulant free HD in 6 long-term maintenance HD patients and assessed changes in various parameters involved in the coagulation-fibrinolysis system. Based on the results, the antithrombogenic properties of various membrane materials were evaluated.<br>Although the thrombin-antithrombin III complex (TAT) values were not significantly changed during HD with heparin, they rose significantly, by 9.1 fold, during anticoagulant free HD as compared to HD with heparin.<br>Among the various HD membranes compared, polyethylene glycol grafted cellulose (PC) membrane was rated superior in terms of antithrombogenicity, since the changes in TAT, percent decrease in platelet counts and PF-4 were smaller, and no residual blood was observed after HD.

We assessed whether increased RBC counts in patients with renal anemia, in response to erythropoietin (EPO) therapy, can be predicted on the basis in reticulocyte (RET) counts before and after the treatment.<br>The subjects consisted of 10 stable hemodialysis (HD) patients who had been on HD for 2 years or more and 8 patients who were in the initial stage of HD.<br>We devised a simulation curve of RBC counts based on the results of serial RBC counts and RET counts before and after EPO administration and various published reports, and derived a formula for predicting increases in RET counts 2 weeks later, i.e. during the period from 4 to 14 weeks after EPO administration.<br>When we applied the RET and RBC counts at 4 weeks after EPO administration to this prediction formula in six of the stable HD patients and compared predicted values with the actual values at 8 weeks, they proved to be very similar, suggesting that it was possible to make the predictions.<br>When the actual values for RBC counts and RET counts were compared with the predicted values in the initial stage HD patients, the actual values were somewhat higher than the predicted values.<br>The average increase in the RBC count 5 weeks after EPO administration was 460, 000 in the stable and 820, 000 in the initial stage HD patients. The latter value was approximately 1.8 times higher than that of the stable HD patients.