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Biomedical subjects

H Ohno

Publications and source records attributed to H Ohno.

At least 595 records · Page 33Linked to original sources
PubMed1981

Fluorescence polarization study on the increase of membrane fluidity of human erythrocyte ghosts induced by synthetic water-soluble polymers.

The effect of water-soluble polymers on the membrane fluidity of human erythrocyte ghosts was investigated and was compared with that of concanavalin A by means of the fluorescence polarization technique. 8-Anilino-1-naphthalene sulfonic acid sodium salt and 1,6-diphenyl-1,3,5-hexatriene were used as probe molecules. The membrane fluidity was increased by the addition of polycations with concentrations of less than 2 x 10(-3) wt% 60 min after mixing. The fluidity changes were affected by the chemical structure (hydrophobicity, charge density, etc.) of polycations. Thus, the membrane fluidity increased markedly with increasing charge density on the chain backbone of polycations. On the other hand, nonionic polymers such as poly(ethylene glycol) and poly(N-vinyl-2-pyrrolidone) changed the membrane fluidity in a biphasic manner. That is, the fluidity of human erythrocyte ghost was temporarily increased and then decrease. For example, 20 wt.% of poly(ethylene glycol) gave a maximum fluidity 15 min after mixing with erythrocyte ghosts. A similar fluidity change was observed by adding concanavalin A. Such fluidity changes were not observed when lipid bilayer vesicles were used instead of cell membranes. These results suggested that the increase of membrane fluidity resulted from the intramembraneous aggregation of membrane-bound proteins which was induced by the added polymers. Cell agglutination was also induced by the addition of a large amount of polymers. This agglutination was considered to be due to the intermembraneous aggregation of membrane-bound proteins.

Concanavalin A↗
PubMed1981

1H-NMR study of the effect of synthetic polymers on the fluidity, transition temperature and fusion of dipalmitoyl phosphatidylcholine small vesicles.

The interaction of water-soluble polymers with dipalmitoyl phosphatidylcholine small vesicles and the effect on vesicle fusion were studied by means of 1H-NMR spectrometry. The motion of dipalmitoyl phosphatidylcholine molecules decreased on interaction with the polymers and was detected as a change in the signal intensity. The interaction behavior of polymers is very sensitive to the chemical structure of the applied polymers. Poly(styrene sulfonic acid) and poly(ethylene glycol) decreased the motion of the choline methyl group, predominantly through coulombic and hydrophobic interaction forces, respectively. For example, in the case of the poly(styrene sulfonic acid)-containing system, the signal intensity of the choline methyl group was decreased about 15% while those of the hydrophobic methylene and terminal methyl groups were scarcely decreased by the addition of polymer to a final concentration of 4.0 x 10(-2) unit mol/l. These polymers are considered to interact with the surface of the vesicle membrane. On the other hand, poly(L-glutamic acid) and poly(N-vinyl-2-pyrrolidone) decreased the signal intensities of not only the choline methyl group, but also those of the hydrophobic methylene and terminal methyl groups. This result suggests that part of these polymers might be incorporated into the hydrophobic region of the vesicle membrane. Addition of the non-ionic polymers inhibited vesicle fusion considerably. This effect was explained by the stabilization of dipalmitoyl phosphatidylcholine vesicles by complexation with these polymers.

Kinetics↗
PubMed1981

Preparation of spherical matrixes of prolonged-release drugs from liquid suspension.

A simple and less expensive method for the preparation of spherical matrixes of prolonged-release drugs was developed from liquid suspension. The drugs dispersed in distilled water were agglomerated with a small amount of organic solution or melt of matrix material. The process, called a "solution" or "melting" method, depended on the state of matrix material. In the present study, sulfamethoxazole and sulfanilamide were agglomerated with white beeswax and ethylcellulose. Furthermore, the parameters affecting the average size and release behavior of the resultant matrixes were investigated. Increasing the amount of matrix material used yielded large matrixes and prolonged-release action. The drugs rendered hydrophobic by surface treatment produced larger matrixes that released drug more slowly than untreated drugs. The sizes of the matrixes decreased and became uniform with increasing agitation speed. The sulfamethoxazole matrixes with wax proved to be enteric coated since the release rate was fast in the alkaline test solution (pH 7.5) but slow in the acidic one (pH 1.2).

Delayed-Action Preparations↗
PubMed1981

Effect of pyridoxal 5-phosphate on the activity of GOT isozyme in plasma from patients with Duchenne muscular dystrophy.

GOT isozyme (soluble GOT, s-GOT and mitochondrial GOT, m-GOT) activities with and without reactivation by the co-enzyme pyridoxal 5-phosphate (PALP) in plasma from 42 patients with Duchenne muscular dystrophy (DMD), and 11 normal controls were investigated. The magnitude of the enzyme activities in patients at the early stage of DMD greatly exceeded those of controls. As the disease progressed, the levels gradually declined, but late stage values were still higher than the control values except s-GOT with PALP. At the mid stage as well as the late stage, the increase in m-GOT activity was approximately to double the unstimulated activity, indicating that, in these patients, as much as half the m-GOT in the circulation was in the inactive apoenzyme form, whereas s-GOT showed negligible increase following PALP addition at any stage.

Adolescent↗
PubMed1980

Studies on antitumor polysaccharides, especially D-II, from mycelium of Coriolus versicolor.

A water-soluble polysaccharide, D-II with marked antitumor activity was isolated from the cultured mycelium of Coriolus versicolor by extraction with hot-water, fractional precipitation with ethanol and ion-exchange chromatography. D-II strongly inhibited the growth of Sarcoma-180 transplanted subcutaneously in mice by intraperitoneal, intravenous, subcutaneous or intra-muscular administration at a dose of 5 mg/kg. the molecular weight was estimated to be 2,000,000 by gel-filtration or 6,500,000 by light scattering analysis. The chemical structure of D-II was then investigated by periodate oxidation, methylation analysis, Smith degradation, and a combination of controlled Smith degradation and methylation analysis. These studies proposed that D-II is composed of a unit structure of four D-glucose residues, and is a glucan consisting of beta-D-1,3-linked main chain in which one for every three D-glucose residues is branched at C-6 with beta-D-1,6-linkage.

Animals↗
PubMed1980

Improvement of the productivity of elasnin, a specific elastase inhibitor, by Streptomyces noboritoensis KM-2753.

Streptomyces noboritoensis KM-2753, an elasnin-producing strain, co-produces an antimycin complex and its elasnin productivity is low (0.006 mg/ml). To obtain mutants possessing higher degrees of elasnin productivity and deficient in antimycin production, the strain was treated with N-methyl-N'-nitro-N-nitrosoguanidine (NTG), ultraviolet light, acriflavine (AF) and high temperature. Mutant N-134 obtained by treatment with NTG was 108 times higher than the original strain in elasnin productivity and produced no antimycin. Strain AF-17 obtained by AF treatment and strain H-80 obtained by incubation at high temperature showed 715 and 428 times higher productivities than that of the original strain, respectively. The productivity of elasnin was further increased 1.6 approximately 2.6 times by addition of saturated fatty acids, especially lauric acid, to the culture. Consequently, strain AF-17 produced 11.1 mg/ml of elasnin in the presence of 10 microgram/ml of lauric acid.

Acriflavine↗