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Biomedical subjects

K Shinohara

Publications and source records attributed to K Shinohara.

At least 325 records · Page 18Linked to original sources
PubMed1984

Cyclic AMP-dependent phosphorylation of erythrocyte variant pyruvate kinase.

Cyclic AMP-dependent phosphorylation of a variant erythrocyte pyruvate kinase (PK; EC 2.7.1.40) was studied. This variant PK shows a faster electrophoretic mobility than the normal enzyme. The decreased enzyme activity observed in this variant is associated with a quantitative decrease of enzyme protein. Other parameters are within normal ranges. The partially purified variant PK is phosphorylated with a subsequent increase of k0.5s (phosphoenolpyruvate) similar to the normal control, suggesting that the structural abnormality of the variant enzyme has no influence on the phosphorylation-deactivation mechanism. On the other hand, the variant PK in the erythrocyte was less extensively phosphorylated than PK in normal erythrocytes. This may be the result of abnormal metabolism in the patient's red cells, including increased 2,3-diphosphoglycerate and decreased adenosine triphosphate levels.

Adolescent↗
PubMed1984

The inhibitory effect of circulating lymphocytes on granulopoiesis in human cyclic neutropenia in vitro.

The effect of peripheral mononuclear cells (MNCs), lymphocytes and sera of a patient with typical cyclic neutropenia (CN) upon the normal colony forming unit in culture (CFU-C) growth was examined. MNCs and lymphocytes obtained during the recovery phase of the cycles inhibited CFU-C growth. In contrast, these cells obtained during the neutropenic phase revealed no suppressive effect. Serum inhibitors of granulopoiesis were not detected at any time during the cycle. These findings suggest that MNCs, especially lymphocytes, may be one of the contributory factors for the development of CN in this case.

Adult↗
PubMed1984

Live varicella vaccine: prevention of nosocomial infection and protection of high risk infants from varicella infection.

For prevention of nosocomial infection, 25 infants including high risk patients received an emergency injection of live varicella vaccine. Three patients developed a rash within 5 days after vaccination, but their symptoms were mild. The other 22 showed no clinical symptoms and gave an immune response. Twenty-two patients receiving immunosuppressive therapy were vaccinated and 20 of them showed a positive response in the varicella skin test. Of 14 vaccinated patients with malignancies, 2 giving a positive skin test, later showed clinical varicella, but their symptoms were not severe. One case with ALL was immunized safely under very poor conditions during the first induction therapy. No complications were observed in any patients.

Chickenpox↗
PubMed1984

[A clinical study on cefoperazone in serious infections associated with hematological malignancy].

Clinical and bacteriological efficiencies of cefoperazone (CPZ) in 19 serious infections associated with hematological malignancy were studied. CPZ was clinically effective in 13 cases (68.4%). Excellent effects were obtained in 3 cases (15.8%), good effects in 7 cases (36.8%) and fairly good effects in 3 cases (15.8%). The rate of clinical effectiveness by CPZ was not dependent on neutrophils number in peripheral blood. Bacteriological effectiveness to isolated organisms in 15 cases was obtained in 9 cases (60%). Clinically significant serum concentrations of CPZ persisted over 6 hours after injection (1 g/l hour, d.i.v.). In comparative study of MIC against clinically isolated P. aeruginosa, CPZ was superior to other cephalosporins. Adverse reactions were not significant except for 3 cases with abnormalities of hepatic function.

Adult↗
PubMed1983

Inhibition and resumption of replicon initiation in X-irradiated mouse L5178Y cells.

Cultured mouse L5178Y cells were irradiated at room temperature with various doses of X-rays, and the rate of 3H-thymidine incorporation was followed for 2 1/2h after exposure. The rate of 3H-thymidine incorporation is affected by two factors; inhibition and resumption of replicon initiation, and chain elongation. A simple method has been developed for estimating the amount of thymidine incorporation which is accounted for by DNA chain elongation after irradiation. This then allows an analysis of the inhibition and resumption of replicon initiation caused by X-rays. The method is based on knowledge of the rate of DNA chain elongation and of the distribution of replicon sizes which are determined by fiber autoradiography. The duration of the inhibition of replicon initiation and the initial slope of the curve showing recovery of initiation were obtained by subtracting the DNA synthesis due to chain elongation from the overall rate of 3H-thymidine incorporation. The interval of depressed DNA synthesis increased with increasing dose of X-rays but only gradually at doses higher than 500 rad. The interval did not exceed 60 min even after 5,000 rad. The initial shope of the curve showing recovery of initiation decreased in a dose dependent manner but very slowly at doses higher than 1,000 rad of X-rays. It appears likely that this initial slope correlates with the relative number of replicons initiating synthesis at the beginning of the recovery period.

Animals↗
PubMed1983

Formation of mutagens by amino-carbonyl reactions.

The formation of mutagens by amino-carbonyl reactions of 20 kinds of amino acid and sugars after heating at 100 degrees C for 10 h was examined by the Ames test. The browned solutions of Gly, Ala, Val, Leu, Ile, Ser, Thr, Gln, Lys X HCl, Arg, Phe, Cys, Met and Pro with Glc caused mutation of Salmonella typhimurium TA100 and/or TA98 with or without S9 mix. The presence of S9 mix increased the mutagenic activity of the browned solutions of Cys and Phe with Glc on TA100 and of those of Gly, Ala, Val, Ile and Cys on TA98, but decreased the activity of other solutions. No revertants of Salmonella were induced by the browned solutions of Trp, Tyr, Asp, Asn, Glu and (Cys)2 with Glc. Among positive browned solutions, Cys, Lys, Arg and Phe had the stronger activity, but their activity was weak compared with that of pyrolysates or chemical mutagens such as Trp-P-1, Trp-P-2 and 4-nitroquinoline-N-oxide. The mutagenic activity of the browned solutions increased with prolongation of heating time and varied with the pH of the reaction mixture. Fru, Gal, Ara, Xyl, Man, Lac and Suc also had the ability to form mutagens in the browning reactions with amino acids.

Amino Acids↗
PubMed1983

Electrophoretic study on the DNA-breaking actions of ascorbic acid and triose reductone in the presence of Cu2+.

The mode of DNA-breaking actions of ascorbic acid (AsA) and triose reductone (TR) in the presence of Cu2+ was studied by use of 0.8% agarose slab gel electrophoretic analysis. The DNA-breaking actions of the mixture of AsA or TR and Cu2+ were inhibited by N2 gas, hydroxyl radical scavengers and catalase, indicating that the oxidation of AsA or TR by Cu2+ and the hydrogen peroxide and hydroxyl radicals resulting from the oxidation are essential for the fragmentation of DNA by the mixture of AsA or TR and Cu2+. However, the DNA-breaking activity of these reductones varied with pH, while their oxidation rates were proportional to the increase in pH. The marked fragmentation of DNA occurred at pH 4, 7 or 8. The breakages of DNA by AsA or TR in the presence of Cu2+ were concluded not to be associated with the oxidation rates of reductones.

Animals↗
PubMed1983

Function of Cu2+ on the DNA-breaking actions of ascorbic acid and triose reductone.

The role of Cu2+ on the DNA-breaking action of ascorbic acid (AsA) and triose reductone (TR) was studied with an agarose slab gel electrophoretic analysis. AsA and TR decomposed calf thymus DNA which had been pretreated with Cu2+, and their decomposing activity was proportional to the concentration of Cu2+ bound to the DNA. The DNA-Cu2+ complex had the ability to oxidize reductones. AsA and TR also decomposed the pretreated DNA with Cu2+ more markedly than that pretreated with Cu2+ and successively with EDTA. The DNA-breaking activity of AsA and TR showed no Cu2+-concentration dependency. The maximal fragmentation of DNA occurred at the concentration ratio of DNA and Cu2+ of 4:1. Excess concentration of Cu2+ decreased the activity of reductones. The present results indicate that the binding of Cu2+ to DNA molecules is also essential for the DNA-breaking action of AsA and TR in the presence of Cu2+ and that Cu2+ bound to DNA molecules has more effective promoting activity than free Cu2+.

Animals↗
PubMed1983

lambda DNA-fragmenting actions of ascorbic acid and triose reductone in the presence of Cu2+.

Lambda DNA-fragmenting actions of ascorbic acid (AsA) and triose reductone (TR) in the presence of Cu2+ were studied. The mixture of AsA or TR and Cu2+ caused a marked fragmentation of lambda DNA (3.2 X 10(7) daltons) within the first 1 min of reaction. Further incubation resulted in accumulation of the most abundant species of fragmented lambda DNA having a molecular weight of 1.3 X 10(5) daltons. The mixture of AsA or TR and Cu2+ fragmented calf thymus DNA to produce the fragmented DNA of which 5'-OH terminal groups have a mixture of free OH groups and phosphodiester linkage. The mixture of AsA or TR and Cu2+ was also found to fragment lambda DNA to produce dCMP predominantly as 5'-OH terminal nucleotides.

Adenosine Triphosphate↗