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Biomedical subjects

K Motohashi

Publications and source records attributed to K Motohashi.

At least 19 recordsLinked to original sources
PubMed1984

Purification and properties of cytochrome P-450 from untreated monkey liver microsomes.

Untreated monkey liver cytochrome P-450 (monkey P-450) has been purified to a specific content of 14.9 n mole/mg protein. The purified preparation was apparently homogeneous and the minimum molecular weight was estimated to be 50,000 by SDS-PAGE. Absolute spectrum of the oxidized form showed peaks at 565, 535 and 417 nm. The monkey P-450 was active in the mixed function oxidation of benzphetamine, aminopyrine, ethylmorphine, aniline and 7-ethoxycoumarin in the presence of rat liver NADPH-cytochrome P-450 reductase and DLPC. Anti monkey P-450 IgG could not inhibit rat P-450s (PB P-450, MC P-448(1) and MC P-448(2] catalyzed 7-ethoxycoumarin O-deethylation activities.

Animals↗
PubMed1983

The bioavailability of flufenamic acid and its dissolution rate from capsules.

The bioavailabilities of five commercially available flufenamic acid (FA) capsules were studied in humans and beagle dogs. The dissolution rates of these capsules were determined by several methods. Experiments on in vitro/in vivo and humans/dogs correlations were performed to evaluate the dissolution test methods and the values of beagle dogs as models for predicting bioavailability of weak acid drugs in humans. Significant differences in the rates and extents of bioavailability of the different capsules were observed both in humans and dogs, but results in humans differed from those in dogs. The dissolution rates, determined by dissolution methods involving pretreatment with acidic solutions, correlated significantly with bioavailabilities in humans and dogs; however, those obtained by the rotating basket and paddle methods without any surface active agents did not correlate with in vivo data.

Adult↗
PubMed1980

Isolation and characterization of a composite plasmid Rms201 mutant temperature sensitive for replication.

A mutant temperature-sensitive for R-plasmid replication, Rms201ts14, was isolated from composite plasmid Rms201 after mutagenesis of P1 transducing lysate with 100 mM hydroxylamine for 40 h at 37 degrees C. When Escherichia coli ML1410(Rms201ts14)(+) was grown at temperatures between 40 and 42 degrees C in L broth, antibiotic-sensitive cells were segregated. When the incubation temperature of ML1410(Rms201ts14)(+) in L-broth was shifted to 42 from 30 degrees C, the increase in the number of antibiotic-resistant cells ceased 90 min after the temperature shift. However, the total number of cells continuously increased, and only 3% of the cells retained the plasmid at 5 h after the temperature shift to 42 degrees C. At 30 degrees C the amounts of covalently closed circular deoxyribonucleic acid per chromosome of Rms201ts14 and Rms201 were 3.8 and 6.3%, respectively. Incorporation of radioactive thymidine into the covalently closed circular deoxyribonucleic acid of Rms201ts14 did not take place at 42 degrees C, whereas radioactive thymidine was incorporated into the covalently closed circular deoxyribonucleic acid of Rms201 at a rate of 4%/chromosome even at 42 degrees C. The synthesis of plasmid covalently closed circular deoxyribonucleic acid in a cell harboring Rms201ts14 was almost completely blocked at 42 degrees C. These results indicated that the gene(s) responsible for plasmid deoxyribonucleic acid replication was affected in the mutant Rms201ts14. Temperature-sensitive miniplasmid pMSts214, which has a molecular weight of 5.3 x 10(6) and encodes ampicillin resistance, was isolated from Rms201ts14. Similarly, miniplasmid pMS201, which encodes single ampicillin resistance, was isolated from its parent, Rms201, and its molecular weight was 4.7 x 10(6). These results indicate that the gene(s) causing temperature sensitivity for replication of Rms201 resides on the miniplasmid.

Ampicillin↗