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Biomedical subjects

S Hara

Publications and source records attributed to S Hara.

At least 613 records · Page 34Linked to original sources
PubMed1982

Effect of hydralazine on hepatic drug metabolizing enzymes in rats.

The effects of hydralazine on hepatic drug metabolizing enzymes were studied in rats. Hydralazine inhibited aminopyrine N-demethylase and aniline hydroxylase in vitro. Kinetic studies indicated that the inhibitory natures of hydralazine were recognized as almost mixed types and a change in difference spectrum demonstrated that hydralazine could bind to cytochrome P-450 as a characteristic type II. A single administration of hydralazine inhibited the drug metabolism, but neither reduction nor induction of the mixed function oxidase system were observed after the hydralazine treatment for 7 days, except the reduction of cytochrome b5 content. In addition, acidophilic degeneration and the formation of acidophilic bodies in liver cells by hydralazine were observed.

Animals↗
PubMed1982

A case of tick bite.

A 30-year-old women suffered from right superior eyelid infestation of Ixodes ovatus Neumann, which was mechanically removed with forceps after application of benzine. No mouth parts were retained in the eyelid. Removed mouth parts were examined by a scanning electron microscope. There were no complications except focal trichotylosis in the involved area. The mode of attachment of the tick to the host and the method of removal were discussed.

Adult↗
PubMed1982

Programmed flow preparation of DNA-oligomers.

A new liquid phase preparation system for the phosphotriester method has been developed in which the usual batch process is carried out by flow manipulations. All processes including reactions, extraction and chromatography separation were performed in glass and PTFE tubing through which the solution was passed along a programmed course controlled by valves. A micro-computer programme was compiled for automatic control of the entire system.

Base Sequence↗
PubMed1981

The three-dimensional structure of the lysozyme produced by Streptomyces erythraeus.

Streptomyces erythraeus lysozyme is different in its amino acid composition, primary structure, and specificity from all other mammalian lysozymes. The structure of the crystalline enzyme has been determined by x-ray diffraction analysis to a resolution of 2.9 A using multiple isomorphous replacement. The primary structure of the enzyme is only partially known and therefore the electron density map has been fitted with all the atoms of the main polypeptide chain and some atoms of the side chain. The enzyme consists of three different domains, and about 18% of the structure has helical conformation. A comparison of the tertiary structure of the bacterial lysozyme with either the mammalian or phage lysozyme does not show any obvious similarities.

Amino Acids↗
PubMed1981

Ligand-dependent reactivity of (Na+ + K+)-ATPase with showdomycin.

Showdomycin inhibited pig brain (Na+ + K+)-ATPase with pseudo first-order kinetics. The rate of inhibition by showdomycin was examined in the presence of 16 combinations of four ligands, i.e., Na+, K+, Mg2+ and ATP, and was found to depend on the ligands added. Combinations of ligands were divided into five groups in terms of the magnitude of the rate constant; in the order of decreasing rate constants these were: (1) Na+ + Mg2+ + ATP, (2) Mg2+, Mg2+ + K+, K+ and none, (3) Na+ + Mg2+, Na+, K+ + Na+ and Na+ + K+ + Mg2+, (4) Mg2+ + K+ + ATP, K+ + ATP and Mg2+ + ATP, (5) K+ + Na + + ATP, Na+ + ATP, Na+ + K+ + Mg2+ + ATP and ATP. The highest rate was obtained in the presence of Na+, Mg2+ and ATP. The apparent concentrations of Na+, Mg2+ and ATP for half-maximum stimulation of inhibition (KS0.5) were 3 mM, 0.13 mM and 4 MicroM, respectively. The rate was unchanged upon further increase in Na+ concentration from 140 to 1000 mM. The rates of inhibition could be explained on the basis of the enzyme forms present, including E1, E2, ES, E1-P and E2-P, i. e., E2 has higher reactivity with showdomycin than E1, while E2-P has almost the same reactivity as E1-P. We conclude that the reaction of (Na+ + K+)- ATPase proceeds via at least four kinds of enzyme form (E1, E2, E1 . nucleotide and EP), which all have different conformations.

Adenosine Triphosphate↗
PubMed1981

Regional distribution of lysosomal enzymes in the retina and choroid of human eyes.

Regional distribution of lysosomal enzymes in the retina and choroid of human eyes was studied biochemically. Specific activities of acid phosphatase, cathepsin D, and arylsulfatase in the retina and choroid varied by area were also studied. The macular area showed the highest activities in comparison to other areas.

Acid Phosphatase↗
PubMed1981

Induction of hypersensitivity of brain by hydralazine treatment in rats.

Pretreatment with hydralazine caused prolongation of hypnosis induced by hexobarbital (80 mg/kg, i.p.) or intracerebroventricular injection of phenobarbital (1 mg/rat). Under the same condition, brain concentration of hexobarbital was lower than that of no hydralazine treatment. In addition, no appreciable change in liver microsomal drug metabolizing enzyme activities of rats after hydralazine treatment was observed. These findings strongly suggested that hydralazine increases the sensitivity of brain to barbiturates, which leads to prolongation of sleeping time without inhibition of drug metabolizing enzymes.

Animals↗
PubMed1981

Heterotransplantation of human urinary bladder cancers in nude mice.

Thirty-one human urinary bladder cancers were transplanted subcutaneously into congenitally athymic nude mice. Subcutaneous growth was obtained in eight at the initial transplantation. Only one of these eight successful transplants, which was derived from squamous cell carcinoma, has been serially transplanted successfully and was characterized by high thromboplastic and low fibrinolytic activities which were virtually constant throughout the serial passages. This strain will provide a useful model system for studying anticancer therapies.

Animals↗