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Biomedical subjects

K Sakaguchi

Publications and source records attributed to K Sakaguchi.

At least 415 records · Page 23Linked to original sources
PubMed1983

Hepatocyte plasma membrane antigens. II. Characterization of liver-specific membrane lipoprotein (LP-1) and Tamm-Horsfall glycoprotein (THGP) like antigens (hepatic THGP) on the plasma membrane of Chang liver cell.

Radioiodinated cell-surface antigens of Chang liver cells recognized with anti-liver-specific membrane lipoprotein (anti-LP-1) and anti-Tamm-Horsfall glycoprotein (anti-THGP) rabbit antibodies were analyzed by the immunoprecipitation followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The analysis revealed that the antigens precipitated with anti-LP-1 were heterogeneous in molecular species consisting of 2 major and 5 minor polypeptides with molecular weights ranging from 36 X 10(3) (36 K) to 250 K daltons. That with anti-urinary THGP was a single polypeptide with a molecular weight of 67 K daltons, which was different from urinary THGP in molecular size, and was designated hepatic THGP.

Antigens, Neoplasm↗
PubMed1983

Photo-oxidation of Jack bean urease in the presence of methylene blue.

Photo-oxidation of Jack bean urease was performed in the presence of a low concentration of methylene blue, which led to the complete loss of the enzymatic activity. The inactivation was more remarkable in an alkaline region than in an acidic region and prevented by the addition of histidine or methionine. Amino acid analysis of the oxidized enzyme revealed that the number of histidine residues had decreased to 73% that of the native enzyme, but the numbers of other amino acid residues were not significantly affected. Benzohydroxamic acid, a specific urease inhibitor, protected the active site of the enzyme against photo-oxidation. On the other hand, oxidation of the enzyme decreased its binding ability with caprylo- and benzohydroxamic acid to one-third. These results suggest that histidine residues are modified by photo-oxidation and are essential to both the enzymatic activity and the binding ability with hydroxamic acid.

Fabaceae↗
PubMed1983

Nasal histamine sensitivity in allergic rhinitis.

Our recent studies of nasal histamine sensitivity in nasal allergy are presented. The sensitivity differed according to the site and size of the nasal mucosa and was correlated with the degree of provocation reaction to antigen. This sensitivity appears to be established in childhood and strongly correlated with the increased sensitivity of histamine receptors as well as the autonomic nervous system dysfunction of the nose.

Adolescent↗
PubMed1983

Intranasal beclomethasone: mode of action in nasal allergy.

The mode of action of topical steroid therapy was investigated in connection with the effects of beclomethasone nasal spray on the three important factors in allergic nasal manifestation: 1) the number of basophilic cells (blood basophils and tissue mast cells) in the nasal mucosa, 2) the sensitivity of the basophilic cells to allergen and 3) the mucosal sensitivity to histamine. The results indicated that of the three factors the inhibition in the accumulation of basophilic cells in the mucosal surface was the most important mode of action of beclomethasone nasal spray.

Administration, Intranasal↗
PubMed1982

Antagonization by cycloheximide of ethyl methanesulfonate-induced 6-thioguanine-resistant mutation and sister-chromatid exchanges.

We studied the effect of cycloheximide (CH) on the induction of mutation and sister-chromatid exchanges (SCEs) in ethyl methanesulfonate (EMS)-treated Chinese hamster cells. At 10(-6)M, CH strongly antagonized the induction of mutation and SCEs and cell survival increased. This suggests that protein synthesis is essential for the induction of mutation as well as SCEs. Results of experiments in which CH treatment preceded or followed exposure to mutagens were similar with respect to the response curves obtained for mutation and SCEs.

Animals↗
PubMed1982

Transformation of Saccharomyces cerevisiae with linear DNA killer plasmids from Kluyveromyces lactis.

Protoplasts of Saccharomyces cerevisiae were mixed with linear DNA plasmids, pGKl1 and pGKl2, isolated from a Kluyveromyces lactis killer strain and treated with polyethylene glycol. Out of 2,000 colonies regenerated on a nonselective medium, two killer transformants were obtained. The pGKl plasmids and the killer character were stably maintained in one (Pdh-1) of them. Another transformant, Pdl-1, was a weak killer, and the subclones consisted of a mixture of weak and nonkiller cells. The weak killers were characterized by the presence of pGKl1 in a decreased amount, and nonkillers were characterized by the absence of pGKl1. The occurrence of two new plasmids which migrated faster than pGKl1 in an agarose gel was observed in Pdl-1 and its subclones, whether weak or nonkillers. Staining with 4',6-diamidino-2-phenylindole revealed that the pGKl plasmids exist in the cytosol of transformant cells with numerous copy numbers.

Ascomycota↗
PubMed1982

Meiosis in Coprinus: characterization and activities of two forms of DNA polymerase during meiotic stages.

Two forms of DNA polymerase have been studied in the basidiomycete Coprinus. DNA polymerase from basidiocarp tissues at zygotene-pachytene stage has been purified 3,500-fold and defined as DNA polymerase b by virtue of its insensitivity to N-ethylmaleimide and by its low molecular weight (76,000). This enzyme has optimal activity at pH 7.0 to 7.5, at 200 mM KCl, and at 25 degrees C incubation temperature. It can use polycytidylic acid-oligo(dG)12-18 as template primer in addition to homodeoxypolymers. The DNA polymerase a is mainly produced in the exponentially growing mycelium. It is sensitive to N-ethylmaleimide and has a temperature optimum at 35 degrees C. At the premeiotic S phase, activities from both polymerase a and polymerase b are found in cell-free extracts. The b enzyme is the only DNA polymerase produced during meiotic prophase. Its assayable activity exhibits two peaks, one at premeiotic S stage and one at pachytene. It is possible that DNA polymerase b is responsible for pachytene repairs involved in recombination.

DNA-Directed DNA Polymerase↗