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Biomedical subjects

Y Murao

Publications and source records attributed to Y Murao.

11 recordsLinked to original sources
PubMed1991

The immunosuppressive effect of hepatocytes in rats--assessment by heart allograft survival and delayed-type-hypersensitivity reactions.

The immunosuppressive effect of hepatocytes was examined experimentally by heart allograft and delayed-type-hypersensitivity (DTH) reactions. The hepatocyte inoculation (1 X 10(7) of BDE (of the major histocompatibility complex haplotype RT1u), LEW (RT1l), and DA (RT1a) into the spleens of LEW rats significantly prolonged the survival of BDE heart allografts to 14.3 +/- 2.7 (mean +/- SD), 9.2 +/- 0.8, and 10.8 +/- 2.3 days respectively, compared with 6.7 +/- 0.8 days in controls (p less than 0.01). Moreover, the BDE hepatocytes had a significantly prolonged survival compared to the LEW (p less than 0.01) and DA (0.02 less than p less than 0.05) groups. BDE hepatocyte (donor specific) inoculation 4 and 7 days before priming with the spleen cells reduced DTH responses in the LEW rats to 44.6 +/- 4.8 per cent, and 74.2 +/- 8.0 per cent, respectively. DA hepatocyte inoculation (third party) 4 and 7 days prior to priming reduced DTH responses to 72.5 +/- 11.5 per cent, and 76.5 +/- 11.9 per cent, respectively. All DTH responses were significantly suppressed after hepatocyte inoculation compared to 100 per cent in the controls (p less than 0.01). Moreover, the inoculation of BDE hepatocytes (donor specific) 4 days prior to the priming significantly reduced DTH responses compared to the group primed 7 days before (p less than 0.01). From these results we concluded that hepatocytes produced not only non-specific but also donor specific immunosuppressive effects through T cell immune reaction. Moreover, donor specific immunosuppressive effects were induced at least 4 to 7 days after hepatocyte inoculation.

Animals↗
PubMed1991

Evaluation of initial hepatic allograft function with changes of free plasma amino acids in canine orthotopic liver transplantation.

We investigated the correlation between amino acid level and hepatic graft function. Plasma amino acid levels were measured at three time periods during canine orthotopic liver transplantation. During the anhepatic phase, plasma amino acid levels rose except for tryptophan. Cystine and alanine (Ala) increased significantly to 210 +/- 28% (n = 20, mean +/- SEM) and 203 +/- 11% from preoperative values (100%), respectively. In animals successfully surviving without hepatic insufficiency after transplantation of fresh livers (n = 7), plasma amino acid levels were restored to preoperative values within 3 hr following reperfusion. On the other hand, in animals that died from hepatic insufficiency within 5 days after grafting of warm ischemically damaged livers (n = 8), plasma amino acids, especially Ala, phenylalanine, total free plasma amino acids, and aromatic amino acids progressively increased to 216 +/- 25, 274 +/- 36, 152 +/- 15, and 152 +/- 15% at 3 hr after reperfusion. These were significantly higher compared to those of the group of animals transplanted with fresh livers (P less than 0.01-0.05). Furthermore, higher values were found in those dogs transplanted with warm ischemically damaged livers surviving for shorter periods. Also in dogs that died from hepatic insufficiency within 8 hr after grafting of livers preserved for 24 hr (n = 5), amino acid levels were at high values at 3 hr. These results suggest that in animals having good graft function, plasma amino acid levels are restored to preoperative values by 3 hr after reperfusion. In other cases, primary nonfunction should be strongly suspected after liver transplantation.

Amino Acids↗
PubMed1984

Complement activation by polymer binding IgG.

It was found that immobilized IgG on polymer carriers activates complement on contact with the serum. As polymers were microspherical in this study, complement fragments bound to polymers were detected by the agglutination of the polymer microspheres with the corresponding antisera or rosette formation with cells having complement receptors. Without the immobilization of IgG, polymers having amino, carboxyl, cyano or phenyl groups activated complement in the serum, while the presence of hydroxyl and carbamoyl groups in polymers did not cause complement activation. When intact IgG was bound to poly(glyceryl methacrylate) by the use of glutaraldehyde, the IgG-polymer conjugate activated complement in spite of the inertness of the polymer itself. The polymers immobilizing F(ab')2 activated complement less than the polymers immobilizing intact IgG. When dextran aldehyde prepared by periodate oxidation of dextran was used as a binder instead of glutaraldehyde, complement activation by F(ab')2-polymer conjugate was remarkably reduced, though antibody activity for binding the antigen remained. These results should be taken into consideration in the design of an immunosorption therapy.

Animals↗
PubMed1983

Preparation of microspheres of poly(glycidyl methacrylate) and its derivatives as carriers for immobilized proteins.

Microspheres of poly(glycidyl methacrylate) and its derivatives have been prepared. The diameter can be varied in the range from 0.5 to 5 micron. Proteins were immobilized on the microspheres by various processes. The maximum amount of covalently immobilized gamma-globulin on the microspheres was found to be about 6 mg/m2. It was shown that dyed microspheres with a diameter of 2-4 micron are applicable to immunological agglutination tests on a microplate as carrier particles substituting for red blood cells.

Acrylates↗
PubMed1982

Polymer microbeads bound to C3 fragments for detecting and labeling cells with C3 receptors.

Monodisperse microbeads (mbs) of a hydrophilic polymer with diameters of 4 microns and 0.2 micron were prepared. To these mbs, IgM or a sugar was bound covalently, and then the mbs were treated with fresh human or mouse serum. This led to the activation of complement and to the binding of C3 fragments to the mbs. C3 fragments fixed on mbs varied with the type of immobilized substance on the mbs and the incubation time of the mbs with fresh serum. Three kinds of mbs binding C3 fragments were prepared: mbs binding C3b, C3bi and C3d (C3hu-mbs); the ones binding C3bi and C3d (C3mu-mbs); and the ones binding only C3b (C3bhu-mbs). They formed rosettes with cells which had the corresponding receptor. When lymphocytes were incubated with C3hu- or C3bhu-mbs with a diameter of 0.2 micron, cap formation of each receptor was observed under a microscope. Once prepared, C3hu-, C3mu- and C3bhu-mbs were stable for more than 4 months.

Animals↗