Shun Murabayashi

Application of magnetic field for biological response modification

The study of magnetic effects on biological system was started in response to Dr. Noses wish for the development of extracorporeal immunomodulation therapy. In the extracorporeal immunomodulation system, monocytes or lymphocytes in blood are stimulated by the interactions with immune-active materials. The concept of magnetic field application was introduced in order to enhance the cell activation. Therefore, the applicability of magnetic field was studied. This paper was concerned with in vitro study of magnetic field effects on macrophage/monocytes and lymphocytes activations. Time-varying magnetic field could enhance macrophages/monocytes and lymphocytes activations.

Biocompatibility: Bioengineering aspects

Bioengineers have contributed to biocompatibility research. Many materials have been designed, synthesized and characterized by use of various analytical instruments. The blood compatibility of materials has been studied by focusing on the blood-material interfacial reactions. Although much information has been accumulated regarding such local reactions, understanding of biocompatibility is still limited. A more global approach to study is needed. A new approach to understanding biocompatibility is proposed and discussed. Three points are stressed: interaction within bodys defense system and its effect on blood-material reactions; induction of a systemic reaction by a local reaction, which then affects the blood-material interaction; the time sequence of such interactions between local and systemic reactions. To establish a logical approach to study biocompatibility is most important at this moment for the future progress in biocompatibility research.

Lymphocyte activation effect of (1→6)-2, 5-anhydro-d-glucitol and it derivatives with 3,4-di-O-methyl and sulfate groups

(1-->6)-2,5-Anhydro-3,4-di-O-methyl-D-glucitol (2a) and (1-->6)-2,5-anhydro-D-glucitol (2c) and its sulfated derivative (2d) were synthesized and their biological activities were evaluated in regards to the effects on murine lymphocytes. The polymers showed different effects on the lymphocytes depending on the substituent groups. The sulfated polymer (2d) induced mitogenic activities, and specifically activated the CD4(-)CD8(-) subset of lymphocytes.

Adsorption of glycated proteins by boronic copolymer-coated adsorbents

The presence of glycated proteins in the plasma of diabetic patients may play a role in serious complications such as nephritis, retinosis, and nerve disorders. We evaluated the adsorption properties of copolymers of styreneboronic acid and styrenesulfonic acid for glycated protein and glycated lipoprotein. Porous glass with pore sizes of 50 and 100nm and cellulose gel were coated with or bound to the copolymer of styreneboronic acid, styrenesulfonic acid, and glycidyl methacrylate. These adsorbents showed selective adsorptivity for glycated albumin and glycated lipoprotein, depending on their boronic acid content. Copolymer composition affects the adsorption properties in a different manner for glycated albumin and glycated lipoprotein, suggesting that not only boronic acid but also sulfonic acid moieties play an important role in adsorption. The copolymer of styreneboronic acid and hydroxyethyl methacrylate had a smaller adsorption capacity than the copolymer of styreneboronic acid and styrenesulfonic acid without positive participation of the hydroxyethyl methacrylate moiety, which also showed the need for sulfonic acid in selective adsorption. Furthermore, these adsorbents had less capacity to activate the intrinsic blood coagulation cascade. Therefore, it may be possible to use these adsorbents to prevent the complications of diabetes by plasmapheresis.The presence of glycated proteins in the plasma of diabetic patients may play a role in serious complications such as nephritis, retinosis, and nerve disorders. We evaluated the adsorption properties of copolymers of styreneboronic acid and styrenesulfonic acid for glycated protein and glycated lipoprotein. Porous glass with pore sizes of 50 and 100nm and cellulose gel were coated with or bound to the copolymer of styreneboronic acid, styrenesulfonic acid, and glycidyl methacrylate. These adsorbents showed selective adsorptivity for glycated albumin and glycated lipoprotein, depending on their boronic acid content. Copolymer composition affects the adsorption properties in a different manner for glycated albumin and glycated lipoprotein, suggesting that not only boronic acid but also sulfonic acid moieties play an important role in adsorption. The copolymer of styreneboronic acid and hydroxyethyl methacrylate had a smaller adsorption capacity than the copolymer of styreneboronic acid and styrenesulfonic acid without positive participation of the hydroxyethyl methacrylate moiety, which also showed the need for sulfonic acid in selective adsorption. Furthermore, these adsorbents had less capacity to activate the intrinsic blood coagulation cascade. Therefore, it may be possible to use these adsorbents to prevent the complications of diabetes by plasmapheresis.

The outline sampling strategies for the femoral CT images

As the result of developments in computer technology in recent years, the calculation, simulation and analysis of the stress environment for the artificial hip prosthesis and the femur have been made possible. In order to perform an exact calculation, three-dimensional modeling with the hip prosthesis and femur is required. The modeling of a femur is done by reconstructing the femoral outline data from CT images using three-dimensional CAD. The outline extraction work is performed by the experience and subjectivity of the operator, and the reliability of the data and working efficiency is low. In this paper, algorithms that extract the femur outline from CT images automatically are proposed.

Bonding strength evaluation of Cementless Implant by grit blasting

As a method of porous coating for cementless implant, sintering and diffusion bonding are usually used. But the bonding techniques have trouble with decreasing fatigue strength and boundary separation. In this study, we applied grit blasting for porous coating. Polygonal iron particle was sprayed on the titanium base material by compressed-air power.