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Biomedical subjects

M Tsuchiya

Publications and source records attributed to M Tsuchiya.

At least 469 records · Page 26Linked to original sources
PubMed1985

Effects of melanin on lysosomal enzymes in bovine ciliary body and iris in vitro.

We studied biochemically the effects of melanin on activities of lysosomal enzymes prepared from the bovine ciliary body and iris in vitro. Melanin was prepared from the bovine ciliary body and iris by acid treatment. Acid phosphatase, N-acetyl-beta-D-glucosaminidase, alpha-D-mannosidase, alpha-L-fucosidase, and beta-D-glucuronidase in the ammonium sulfate fraction were used as lysosomal marker enzymes. After the enzyme solution was incubated with melanin, enzyme activity was reduced and protein content in the supernatant was decreased. Each enzyme showed a different activity. The data suggested that 1) the decreased activity may depend on the affinity of lysosomal enzyme protein for melanin and 2) each enzyme may have a different affinity for melanin. These findings were discussed with respect to biochemical interaction between melanin and lysosomal enzymes in the ocular tissue in vivo.

Acid Phosphatase↗
PubMed1985

Demonstration and characterization of immunosuppressive factors in sera from patients with Crohn's disease.

The effect of sera from 17 patients with Crohn's disease, 8 with ulcerative colitis or 5 with intestinal tuberculosis on the proliferative response of mouse spleen cells induced by phytohemagglutinin (PHA) was studied. Sera from patients with Crohn's disease markedly suppressed the blastogenesis of mouse spleen cells (S.I. = 6.8 +/- 2.0, % suppression = 83%), as compared with normal sera (S.I. = 41.0 +/- 5.2, p less than 0.001, % suppression = 0). Conversely, ulcerative colitis sera did not suppress the blastogenesis of mouse spleen cells (S.I. = 43.5 +/- 8.7, % suppression = -6%), nor the sera of intestinal tuberculosis (S.I. = 38.9 +/- 4.0, % suppression = 6%). Thus, we confirmed the possible existence of immunosuppressive factors in Crohn's disease. Moreover, immunosuppressive factors in Crohn's disease were characterized for biochemical properties. The approximate molecular weight is 45,000 estimated by diafiltration and gel filtration on a Sephadex G-75 column. Analytical isoelectric focusing showed an increased amount of acidic protein in fractionated sera (m.w. ranging 30,000-50,000) from patients with Crohn's disease and ulcerative colitis, in comparison with that in normal sera. Furthermore, the main peak of this acidic protein in Crohn's disease was an isoelectric point (pI) of 2.8, while the pI of that from ulcerative colitis was 3.0. These results suggest that qualitative differences of such acidic protein may serve to discriminate between the sera of Crohn's disease and ulcerative colitis.

Adolescent↗
PubMed1985

Pericentral pigmentary retinal degeneration.

We studied five patients with pericentral pigmentary retinal degeneration, whose fundus lesions were bilateral, symmetrical grayish zones with pigments surrounding the macular region. All showed good visual acuity, normal color vision, mild deterioration of scotopic electroretinographic response, normal photopic electroretinographic response, subnormal electrooculogram and paracentral ring scotoma. The fluorescein angiography demonstrated hyperfluorescent dots around the macula. Their family history was noncontributory. The retinal lesions showed only very slow progression.

Adult↗
PubMed1984

Enzyme-linked immunosorbent assay for detection of receptors for polymerized human serum albumin on hepatitis B surface antigen particles.

An enzyme-linked immunosorbent assay (ELISA) was developed to detect the polymerized human serum albumin (pHSA) receptor on hepatitis B virus surface antigen (HBsAg) particles. The receptor values on particles from HBeAg-positive patients were significantly higher than those from anti-HBe-positive and HBeAg-, anti-HBe-negative patients. In patients' sera with moderate to high receptor values, there was significant correlation between the values obtained in the ELISA and serum DNA-polymerase activity (P less than 0.005), but not with HBeAg titer. During a 1-year follow-up of 47 HBeAg-positive patients with chronic hepatitis, termination of active viral replication, as evidenced by seroconversion from HBeAg to anti-HBe-positive, was observed in 1 of 26 with high initial receptor values, 2 of 12 with moderately high values and 6 of 9 with low receptor values. The results suggest that the ELISA described, which detects pHSA receptors on HBsAg particles, might be of value as a prognostic test in HBeAg-positive chronic hepatitis type B.

DNA-Directed DNA Polymerase↗
PubMed1984

Possible participation of Ca2+, Mg2+-dependent endonuclease in liver DNA fragmentation after N-methyl-N-nitrosourea treatment.

We examined the fragmentation of DNA treated with N-methyl-N-nitrosourea under conditions in which Ca2+, Mg2+-dependent endonuclease is active. The molecular mass of DNA found in mouse liver slices treated with methylnitrosurea in the presence of Ca2+ plus Mg2+ was 4 X 10(5) Da. Similar results were obtained with a reconstituted system containing partially purified Ca2+, Mg2+-dependent endonuclease and methylnitrosurea-treated DNA. The enzyme extensively cleaved methylnitrosurea-treated DNA, compared with non-treated DNA. The methylnitrosurea-treated nuclear proteins obtained from mouse liver nuclei had no effect on the DNA fragmentation by the enzyme. Using closed-circular DNA treated with methylnitrosurea, the enzyme produced single-strand cuts in the DNA, as was seen in non-treated, closed-circular DNA, however, the rate of hydrolysis was increased. Ca2+, Mg2+-dependent endonuclease thus warrants further investigation, with regard to the precise mechanism of extensive degradation of DNA in cells treated with carcinogenic alkylating agents.

Animals↗
PubMed1984

ADP-ribosyltransferase from hen liver nuclei. Purification and characterization.

Chromatin-bound ADP-ribosyltransferase from adult hen liver nuclei was purified to a homogeneous state through salt extraction, gel filtration, hydroxyapatite, phenyl-Sepharose, Cm-cellulose, and DNA-Sepharose. The ADP-ribosyltransferase has a pH optimum at 9.0 and does not require DNA for reaction. The purified enzyme has a molecular weight of 27,500 +/- 500. Agmatine sulfate, arginine methyl ester, histones, and casein proved to be effective acceptors for the ADP-ribose molecule. Among histones, H3 was most active, followed by H2a, H4, and H2b, in that order, the lowest activity seen with H1. With all the acceptors tested, the rate of nicotinamide release was in excess of the ADP-ribosylation. However, changes in the ratio of nicotinamide release to ADP-ribosylation seemed to depend on concentrations of the acceptor used. ADP-ribose-whole histones X adducts formed by ADP-ribosyltransferase served as initiators for poly(ADP-ribose) synthesis when these adducts were incubated in the presence of NAD, DNA, Mg2+, and the purified poly(ADP-ribose) synthetase, in which poly(ADP-ribose) formation can occur.

Animals↗
PubMed1984

Polymorphism of human liver alcohol dehydrogenase: identification of ADH2 2-1 and ADH2 2-2 phenotypes in the Japanese by isoelectric focusing.

Liver homogenate-supernatants from most Japanese exhibit an "atypical" pH optimum for ethanol oxidation at pH 8.8 instead of 10.5, the "typical" pH-activity optimum. It has been proposed that atypical livers contain alcohol dehydrogenase isozymes with beta 2 subunits while typical livers contain isozymes with beta 1 subunits, both produced by the ADH2 gene. Because it is difficult to differentiate the atypical ADH2 2-2 phenotype from the ADH2 2-1 phenotype by starch gel electrophoresis, an agarose isoelectric focusing procedure was developed that clearly separated the atypical Japanese livers into two groups, A1 and A2. The beta beta isozymes in A1 and A2 livers were purified. Type A1 livers contained a single beta beta isozyme with an atypical pH-rate profile; it was designated beta 2 beta 2. Three beta beta isozymes were isolated from A2 livers, two of which corresponded to beta 1 beta 1 and beta 2 beta 2. A third, absent from the typical and the atypical A1 livers, had an intermediate mobility; it was designated beta 2 beta 1. Type A1 livers are, therefore, the homozygous ADH2 2-2 phenotype, and type A2 livers, the heterozygous ADH2 2-1 phenotype. The ADH2 2-2 phenotype was found in 53% of 194 Japanese livers, and the ADH2 2-1 phenotype, in 31%. Accordingly, the frequency of ADH2(2) was 0.68.

Adult↗
PubMed1984

Microcirculatory responses to estradiol benzoate in chronic liver damage induced by carbon tetrachloride in the rat.

Microcirculatory responses to estradiol benzoate (ES) under condition of chronic liver damage induced by long-term administration of carbon tetrachloride (CCl4) was investigated in the rat. One hundred and five male rats were divided into the following groups receiving 0.1 mg/100 g body weight ES injected intraperitoneally 5 times per week: controls, exposed to CCl4 alone; rats treated with ES from the fourth week of CCl4 exposure; animals treated with ES from the 11th week of CCl4 exposure. In rats receiving CCl4 alone, liver cirrhosis was induced by 10 consecutive weeks of exposure. Microangiograms of the liver demonstrated conspicuous rarefaction of the vascular tree. On the other hand, animals treated with ES had neither atrophic liver nor rarefaction of the intrahepatic vascular tree. ES produced also intrahepatic neovascular proliferation in the cirrhotic liver. After long-term CCl4 administration, ES treated rats had extremely enlarged nodules with tumor-stain like findings, giving rise to a structure differing from hepatocellular carcinoma which latter generally displays a broom-swept appearance. It is concluded that in providing potent angiogenesis in the liver, ES protects the liver against microcirculatory dearangement and parenchymal damage induced by CCl4.

Angiography↗