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Introduction: Polysulfone (PSf) membrane has been widely used for hemodialysis. A few studies have been reported in which a method of sterilization may affect biocompatibility. In this study, the comparison was made between two PSf membranes in order to evaluate the effect of sterilization from the biocompatibility point of view. Methods: We investigated the biocompatibility of the following two dialyzers, that is, APS‐11SA (Asahi Kasei medical Co., Tokyo, Japan), sterilized by gamma‐ray irradiation, and RENAK PS‐1.0 (Kawasumi laboratories, Tokyo, Japan), sterilized by autoclave. Heparin of 40 units/mL was put in a syringe, and test blood was collected from healthy volunteers. Then, the dialyzer and blood circuit were filled with the test blood. Subsequently, the blood was circulated by a roller pump at the rate of 200 mL/min. We measured the platelet counts, CD41 and CD42b platelet surface markers, beta‐thromboglobulin (beta‐TG) and platelet factor 4 (PF4) at 30, 120, and 240 minutes, respectively. Findings: The platelet counts at 30, 120, and 240 minutes decreased significantly from the initiation of blood circulation in both dialyzers. The average beta‐TG and PF4 increased from 61.3 ± 22.1 and 17.0 ± 6.4 ng/mL to 680.7 ± 217.1 and 550.7 ± 116.7 ng/mL with APS‐11SA and to 454.3 ± 85.6 and 402.0 ± 58.0 ng/mL with RENAK PS‐1.0, respectively. The average expression of CD41 and CD42b in APS‐11SA and RENAK PS‐1.0 was similar. Discussion: There are some reports that the gamma‐ray irradiation changes the membrane structure of the PSf membrane, crosslinking the polyvinylpyrrolidone (PVP), a hydrophilic agent, on to the membrane. On the other hand, excess amount of PVP may have been eluted during the rinsing procedure in RENAK PS‐1.0 because it was sterilized with autoclave. Because both these factors influenced on our results, APS‐11SA and RENAK PS‐1.0 dialyzers showed excellent blood compatibility.

Objective: Solute removal performance of the dialyzer is closely related to physicochemical structures of the membrane. The objective of this study is to devise a new in vitro evaluation technique to directly correlate the physicochemical structures of the membrane to the dialysis performance.Materials and Methods: Commercial 11 dialyzers with cellulose triacetate (CTA), ethylene vinylalcohol co-polymer (EVAL), asymmetry CTA (termed ATA), 4 polysulfone (PSf), polyether sulfone (PES), and 3 polyester polymer alloy (PEPA) membranes were employed for investigation. Normal dialysis experiments were performed with aqueous creatinine (MW 113), bromophenol blue (MW 670), vitamin B 12 (MW 1355), chymotrypsin (MW 25,000) test solutions. Reversal dialysis experiments were devised introducing the test solution outside the hollow fiber (HF) and the dialysate inside the HF, respectively. Clearances were measured under Q B 5 200 mL/min and Q D 5 500 mL/ min at 310 K. The ratio of clearance in the reversal dialysis to that in the normal dialysis termed the yielding factor of asymmetry, f YA , was defined for evaluation.Results and Discussion: According to the classic mass transfer theory, clearance in the normal dialysis and that in the reversal dialysis are expected to be identical; however, the average f YA was 0.96 for creatinine and was always slightly lower than unity in 10 dialyzers out of 11. This may be caused by un-uniform distribution of the test solution outside the HF, which was more likely to occur than when it flowed inside the HF. Unlike creatinine, the average f YA for vitamin B 12 was 1.0 and that for chymotrypsin was 1.06 to 1.45 in membranes with heterogeneous structures (ATA, PSf, PEPA, and PES), but was almost unity (1.02) in homogeneous membrane (CTA). This must be based on the fact that the membrane permeability in the reversal dialysis is much larger than that in the normal dialysis due to the physicochemical structures of the heterogeneous membrane that has a wedge-like pore size distribution in the radial direction.Conclusions: A wedge-like pore size distribution in the radial direction in heterogeneous membrane was semiquantitatively evaluated by introducing a reversal dialysis technique with a new index.

An asymptomatic 52-year-old male, who was diagnosed as poorly controlled diabetes mellitus (DM), was referred to our hospital because of abnormal shadows on chest X-rays. Physical examinations and laboratory data showed no abnormal findings except increased values of blood sugar and HbA1c (12.1%). Chest X-ray and CT scan revealed multiple nodular shadows in both lung fields. The specimens from transbronchial biopsy showed epithelioid granuloma, and Mycobacterium tuberculosis was confirmed with bronchial wash fluid. The patient was then treated with antimycobacterial drugs and sulfonylurea along with diet therapy. The multiple nodular shadows gradually disappeared. It seemed that impaired host defense mechanisms caused by poorly controlled DM is responsible for the bronchogenic dissemination of M. tuberculosis, resulting in the extension into the multiple nodular shadows. Thus, a good control of DM is important for the prevention of an onset and excerbation of tuberculosis in patients with DM.

Performance of the dialysis membrane is strongly dependent upon the physicochemical structure of the membrane. The objective of this study is to devise a new in vitro evaluation technique to quantify the physicochemical structures of the membrane. Three commercial dialyzers with cellulose triacetate (CTA), asymmetric CTA (termed ATA®), and polyether sulfone (PES) membranes (Nipro Co., Osaka, Japan) were employed for investigation. Forward and backward ultrafiltration experiments were performed separately with aqueous vitamin B12 (MW 1355), α-chymotrypsin (MW 25,000), albumin (MW 66,000) and dextran solutions, introducing the test solution inside or outside the hollow fiber (HF), respectively. Sieving coefficients (s.c.) for these solutes were measured under the test solution flow rate of 200 mL/min and the ultrafiltration rate of 10 mL/min at 310 K, according to the guidelines provided by Japanese academic societies. We defined the ratio of s.c. in the backward ultrafiltration to that in the forward ultrafiltration and termed it the index for asymmetricity (IA). The IA values were unity for vitamin B12 and α-chymotrypsin in all three of the dialyzers. The IA values for albumin, however, were 1.0 in CTA, 1.9 in ATA®, and 3.9 in PES membranes, respectively, which corresponded well with the fact that CTA is homogeneous, whereas ATA® and PES are asymmetrical in structure. Moreover, the asymmetricity of ATA® and PES may be different by twofold. This fact was verified in continuous basis by employing dextran solution before and after being fouled with albumin. These findings may contribute to the development of a novel membrane for improved success of dialysis therapy.