The Experts below are selected from a list of 6165 Experts worldwide ranked by ideXlab platform
Masanori Abe - One of the best experts on this subject based on the ideXlab platform.
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effect of dialyzer membrane materials on survival in chronic hemodialysis patients results from the annual survey of the japanese nationwide dialysis registry
PLOS ONE, 2017Co-Authors: Masanori Abe, Takayuki Hamano, Atsushi Wada, Shigeru Nakai, Ikuto MasakaneAbstract:Background Little information is available regarding which type of dialyzer membrane results in good prognosis in patients on chronic hemodialysis. Therefore, we conducted a cohort study from a nationwide registry of hemodialysis patients in Japan to establish the association between different dialyzer membranes and mortality rates. Methods We followed 142,412 patients on maintenance hemodialysis (female, 39.1%; mean age, 64.8 ± 12.3 years; median dialysis duration, 7 [4–12] years) for a year from 2008 to 2009. We included patients treated with seven types of high-flux dialyzer membranes at baseline, including cellulose triacetate (CTA), ethylene vinyl alcohol (EVAL), polyacrylonitrile (PAN), polyester Polymer Alloy (PEPA), polyethersulfone (PES), polymethylmethacrylate (PMMA), and polysulfone (PS). Cox regression was used to estimate the association between baseline dialyzers and all-cause mortality as hazard ratios (HRs) and 95% confidence intervals for 1-year mortality adjusting for potential confounders, and propensity score matching analysis was performed. Results The distribution of patients treated with each membrane was as follows: PS (56.0%), CTA (17.3%), PES (12.0%), PEPA (7.5%), PMMA (4.9%), PAN (1.2%), and EVAL (1.1%). When data were adjusted using basic factors, with PS as a reference group, the mortality rate was significantly higher in all groups except for the PES group. When data were further adjusted for dialysis-related factors, HRs were significantly higher for the CTA, EVAL, and PEPA groups. When the data were further adjusted for nutrition-and inflammation-related factors, HRs were significantly lower for the PMMA and PES groups compared with the PS group. After propensity score matching, HRs were significantly lower for the PMMA group than for the PS group. Conclusion The results suggest that the use of different membrane types may affect mortality in hemodialysis patients. However, further long-term prospective studies are needed to clarify these findings, including whether the use of the PMMA membrane can improve prognosis.
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Characterization of insulin adsorption behavior of dialyzer membranes used in hemodialysis.
Artificial organs, 2011Co-Authors: Masanori Abe, Kazuyoshi Okada, K. Ikeda, Shiro Matsumoto, Masayoshi Soma, K MatsumotoAbstract:Although it has been reported that plasma insulin is removed by hemodialysis (HD), the mechanism for this has not been elucidated. We investigated the mechanism of insulin removal during HD treatment and the characteristics of insulin removal with three high-flux membranes. In our in vivo study, 20 stable diabetic patients on HD were randomly selected for three HD sessions with three different membranes: polysulfone (PS), cellulose triacetate (CTA), and polyester Polymer Alloy (PEPA). Blood samples were obtained from the blood tubing at the arterial (A) site at the beginning and end of the sixth HD session to investigate insulin reduction in patients. At 1 h after the initiation of dialysis, blood samples were obtained from both the A and venous sites of the dialyzer to investigate the insulin clearance with the different membranes. There was a significant reduction in patients' plasma insulin at each time point with each of the three membranes. The insulin clearance with the PS membrane was significantly higher than that with the CTA and PEPA membranes. Although no difference was observed in the plasma insulin reduction rate between the three membranes in the total subject group, there was a significantly higher reduction rate with the PS membrane in insulin-dependent diabetes mellitus subjects. The clearance of insulin in in vitro tests was significantly higher with the PS and PEPA membranes than with the CTA membrane in both new and clinically used dialyzers. Insulin was not detected in the dialysate or ultrafiltration fluids in either the in vivo or in vitro studies. The mechanism of plasma insulin clearance by HD is mainly by adsorption, and the amount of insulin adsorbed differed depending on the dialyzer membrane used.
Kazuhiko Ishihara - One of the best experts on this subject based on the ideXlab platform.
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hybridization of poly 2 methacryloyloxyethyl phosphorylcholine block 2 ethylhexyl methacrylate with segmented polyurethane for reducing thrombogenicity
Colloids and Surfaces B: Biointerfaces, 2013Co-Authors: Yoshiharu Asanuma, Yuuki Inoue, Shin-ichi Yusa, Kazuhiko IshiharaAbstract:Segmented polyurethanes (SPUs) are widely used in biomedical devices owing to their superior mechanical properties. However, their applicability in blood-contacting devices such as small-diameter vascular prostheses is severely limited owing to their thrombogenicity. Thus, it is necessary to develop an SPU material that has a surface with low thrombogenicity. In this study, poly(2-methacryloyloxyethyl phosphorylcholine-block-2-ethylhexyl methacrylate) (B-PMEH) was synthesized as a well-defined diblock coPolymer by reversible addition–fragmentation chain transfer (RAFT) Polymerization. B-PMEH was hybridized with SPU by the integration of the Polymer layers to prepare an SPU/B-PMEH Polymer Alloy membrane (SB membrane). The MPC units in the B-PMEH phase separated on the immersion of the SB membrane in water, producing a surface that drastically lowered the amount of the absorbed fibrinogen and platelet adhesion as compared to the SPU. Importantly, it was demonstrated that the bulk mechanical properties of the SPU were not affected by the addition of B-PMEH.
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pressure induced change in permeation of insulin through a Polymer Alloy membrane for an implantable insulin pump
Journal of Membrane Science, 2002Co-Authors: Tomoaki Uchiyama, Junji Watanabe, Kazuhiko IshiharaAbstract:Abstract Pressure-induced change in insulin permeability through a Polymer Alloy membrane for an implantable insulin pump was investigated. The Polymer Alloy membrane was composed of a segmented polyurethane (SPU) and poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-2-ethylhexyl methacrylate) (PMEH). The Polymer Alloy membrane had a pathway for insulin permeation because the hydrophilic PMEH became the domain structure in the Polymer Alloy. The functions of the SPU/PMEH Alloy membrane were characterized in terms of insulin permeability and water permeability with an applied pressure, mechanical properties, and strain and volume changes under the pressured condition. The insulin permeability synchronized with the applied pressure, that is, the insulin permeability increased 3.4 times with the applied pressure (pressure-on state) of 18 kPa in comparison with no applied pressure (pressure-off state). The permeability changed reversibly without lag time between the pressure-on and -off states. The phenomenon was caused by an increase in water permeation with the applied pressure. From the observation of volume change in the insulin reservoir in the pressure-on state, the effective pressure advancing water permeation was produced by the elasticity of the Polymer Alloy membrane. The Polymer Alloy membrane had excellent mechanical properties resisting the applied pressure, as was indicated by stress–strain measurements. It was concluded that the SPU/PMEH Alloy membrane had a useful function for an implantable insulin pump.
K Matsumoto - One of the best experts on this subject based on the ideXlab platform.
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Characterization of insulin adsorption behavior of dialyzer membranes used in hemodialysis.
Artificial organs, 2011Co-Authors: Masanori Abe, Kazuyoshi Okada, K. Ikeda, Shiro Matsumoto, Masayoshi Soma, K MatsumotoAbstract:Although it has been reported that plasma insulin is removed by hemodialysis (HD), the mechanism for this has not been elucidated. We investigated the mechanism of insulin removal during HD treatment and the characteristics of insulin removal with three high-flux membranes. In our in vivo study, 20 stable diabetic patients on HD were randomly selected for three HD sessions with three different membranes: polysulfone (PS), cellulose triacetate (CTA), and polyester Polymer Alloy (PEPA). Blood samples were obtained from the blood tubing at the arterial (A) site at the beginning and end of the sixth HD session to investigate insulin reduction in patients. At 1 h after the initiation of dialysis, blood samples were obtained from both the A and venous sites of the dialyzer to investigate the insulin clearance with the different membranes. There was a significant reduction in patients' plasma insulin at each time point with each of the three membranes. The insulin clearance with the PS membrane was significantly higher than that with the CTA and PEPA membranes. Although no difference was observed in the plasma insulin reduction rate between the three membranes in the total subject group, there was a significantly higher reduction rate with the PS membrane in insulin-dependent diabetes mellitus subjects. The clearance of insulin in in vitro tests was significantly higher with the PS and PEPA membranes than with the CTA membrane in both new and clinically used dialyzers. Insulin was not detected in the dialysate or ultrafiltration fluids in either the in vivo or in vitro studies. The mechanism of plasma insulin clearance by HD is mainly by adsorption, and the amount of insulin adsorbed differed depending on the dialyzer membrane used.
Yoichi Jinbo - One of the best experts on this subject based on the ideXlab platform.
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polyester Polymer Alloy as a high performance membrane
Contributions To Nephrology, 2011Co-Authors: Tadaaki Igoshi, Narumi Tomisawa, Yoshinori Hori, Yoichi JinboAbstract:Polyester Polymer Alloy (PEPA) membrane is developed as a synthetic Polymermembrane. It consists of two Polymers – polyethersulfone (PES) and polyarylate (PAR).The pore size in membrane can be controlled by a blend ratio of PES and PAR. One unique characteristic is that PEPA membrane has three layers of a skin layer on the inner surface, a porous layer in the membrane, and a skin layer on the outer surface, respectively. The permeability of water and substances is controlled by the skin layer on the inner surface. PEPA membrane dialyzer can be adequately considered as a high-performance dialyzer. Furthermore, the skin layer on the outer surface can block endotoxin from the dialysis fluid side. PEPA membrane can therefore be used as an endotoxin-retentive filter. The other unique characteristic is that each amount of albumin loss or β2-microglobulin removal can be controlled by an additive amount of polyvinylpyrrolidone. This means that the PEPA dialyzer can be clinically used to meet the conditions of the patient.
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polyester Polymer Alloy as a high performance membrane
Contributions To Nephrology, 2011Co-Authors: Tadaaki Igoshi, Narumi Tomisawa, Yoshinori Hori, Yoichi JinboAbstract:Polyester Polymer Alloy (PEPA) membrane is developed as a synthetic Polymermembrane. It consists of two Polymers – polyethersulfone (PES) and polyarylate (PAR).The pore size in membrane can be controlled by a blend ratio of PES and PAR. One unique characteristic is that PEPA membrane has three layers of a skin layer on the inner surface, a porous layer in the membrane, and a skin layer on the outer surface, respectively. The permeability of water and substances is controlled by the skin layer on the inner surface. PEPA membrane dialyzer can be adequately considered as a high-performance dialyzer. Furthermore, the skin layer on the outer surface can block endotoxin from the dialysis fluid side. PEPA membrane can therefore be used as an endotoxin-retentive filter. The other unique characteristic is that each amount of albumin loss or β2-microglobulin removal can be controlled by an additive amount of polyvinylpyrrolidone. This means that the PEPA dialyzer can be clinically used to meet the conditions of the patient.
Ikuto Masakane - One of the best experts on this subject based on the ideXlab platform.
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effect of dialyzer membrane materials on survival in chronic hemodialysis patients results from the annual survey of the japanese nationwide dialysis registry
PLOS ONE, 2017Co-Authors: Masanori Abe, Takayuki Hamano, Atsushi Wada, Shigeru Nakai, Ikuto MasakaneAbstract:Background Little information is available regarding which type of dialyzer membrane results in good prognosis in patients on chronic hemodialysis. Therefore, we conducted a cohort study from a nationwide registry of hemodialysis patients in Japan to establish the association between different dialyzer membranes and mortality rates. Methods We followed 142,412 patients on maintenance hemodialysis (female, 39.1%; mean age, 64.8 ± 12.3 years; median dialysis duration, 7 [4–12] years) for a year from 2008 to 2009. We included patients treated with seven types of high-flux dialyzer membranes at baseline, including cellulose triacetate (CTA), ethylene vinyl alcohol (EVAL), polyacrylonitrile (PAN), polyester Polymer Alloy (PEPA), polyethersulfone (PES), polymethylmethacrylate (PMMA), and polysulfone (PS). Cox regression was used to estimate the association between baseline dialyzers and all-cause mortality as hazard ratios (HRs) and 95% confidence intervals for 1-year mortality adjusting for potential confounders, and propensity score matching analysis was performed. Results The distribution of patients treated with each membrane was as follows: PS (56.0%), CTA (17.3%), PES (12.0%), PEPA (7.5%), PMMA (4.9%), PAN (1.2%), and EVAL (1.1%). When data were adjusted using basic factors, with PS as a reference group, the mortality rate was significantly higher in all groups except for the PES group. When data were further adjusted for dialysis-related factors, HRs were significantly higher for the CTA, EVAL, and PEPA groups. When the data were further adjusted for nutrition-and inflammation-related factors, HRs were significantly lower for the PMMA and PES groups compared with the PS group. After propensity score matching, HRs were significantly lower for the PMMA group than for the PS group. Conclusion The results suggest that the use of different membrane types may affect mortality in hemodialysis patients. However, further long-term prospective studies are needed to clarify these findings, including whether the use of the PMMA membrane can improve prognosis.