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Biomedical subjects

T Ochi

Publications and source records attributed to T Ochi.

At least 325 records · Page 18Linked to original sources
PubMed1981

Induction of chromosomal aberrations and 8-azaguanine-resistant mutations by aryldialkyltriazenes in cultured mammalian cells.

Inducibility of chromosomal aberrations, cell survival, and mutation to 8-azaguanine (8AG) resistance in cultured V79 cells by 1-phenyl-3,3-dimethyltriazene (PDMT), 1-phenyl-3,3-diethyltriazene (PDET), and 1-(pyridyl-3)-3,3-diethyltriazene (PyDET) were examined with or without metabolic activation. Chromosomal aberrations were induced in a dose-dependent manner by all 3 triazenes in a direct treatment for 24 h. Chromosomal aberrations were also induced by PDMT with metabolic activation system for 3 h, and little differences in the incidences were observed compared with those obtained by a direct treatment. All 3 triazenes were slightly mutagenic in a direct treatment for 24 h. In metabolic activation experiments, however, PDMT and PyDET were highly mutagenic. The mutagenicity, when compared with the cytotoxicity, was significantly higher in a metabolic activation system than in a direct treatment.

Animals↗
PubMed1981

A comparative study of assay systems for drug-resistant mutation in cultured mammalian cells.

Three assay methods which have been reported previously for the detection of drug-resistant mutation in mammalian cells were compared using V79 cells growing monolayer and FM3A cells growing in suspension. 8-Azaguanine and ouabain were used for the selection. A method in which mutagen-treated cells were replated and cultured in the control medium during expression period, followed by the incubation in a selection medium (we named immediate replating method), was more efficient for demonstrating mutated cells than other replating methods in every occasions examined. Further, the optimum expression periods by this method were shown to be 3 to 4 cell divisions after the replating on cells treated with different concentrations of a mutagen.

Animals↗
PubMed1980

Immunochemical quantitation of complement components of Clq and C3 in sera and synovial fluids of patients with bone and joint diseases.

The amount of the initiating complement component (Clq) in the classical pathway and the first essential component (C3) in the alternative complement pathway were measured with a single radial immunodiffusion (SRID). A high ionic strength was used corresponding to that of 0 . 25 M NaCl and 0 . 01 M EDTA to avoid nonspecific binding of Clq with immune aggregates. Measurements were made on sera and/or synovial fluids from 165 patients with various bone and joint diseases. Values of Clq and C3 in synovial fluids were also expressed as ratios to that of albumin in the same specimens to avoid the influence of differences in volume of synovial fluid in various diseases, and this appeared to provide a reliable index reflecting pathological conditions. Both serum Clq and C3 levels were raised highly in rheumatoid arthritis, gout, and osteomyelitis, but the extent of the elevation of C3 was less conspicuous. Values of Clq and C3 in synovial fluids also markedly increased in rheumatoid arthritis.

Adolescent↗
PubMed1980

Identification of type A and type C virus particles in BF murine osteosarcoma.

Two types of virus particles, intracisternal type A and extracellular type C with budding, were detected in the same cells of BF osteosarcoma, its cultured cell lines, and their BFO tumors in CBA mice. The type C particles were approximately 100 microns in diameter. The buoyant density of the virions was 1.16g/ml in sucrose and 1.07 g/ml in Ficoll. A 72S RNA was demonstrated by gel electrophoresis, but no DNA was detected. Reverse transcriptase activity was also demonstrated in detergent-treated virions. Thus, the particles seem to be RNA virus. Cellular transformation and focus formation were observed after rat and mouse embryo cell monolayers were infected with the virus. The same kind of osteosarcoma was produced by inoculation of cloned transformed cells (BFOSV) of CBA embryo cells into CBA mice. Thus, the virus seems to be an oncornavirus.

Animals↗
PubMed1980

Osteogenesis by factor(s) isolated from mouse osteosarcoma cells in combination with collagen.

An osteogenic factor(s) was extracted with acetic acid from cultures of mouse osteosarcoma cells. The extract was mixed with acid-soluble human skin collagen as a carrier and the mixture was aggregated by dialysis against 0.02 M Na2HPO4. Thirty days after implanting the resulting precipitate into the muscle pouch of mice, new bone formation was observed at the site of implantation. Only fibrous tissue was formed in controls implanted with acid-soluble collagen alone. Therefore, it was concluded that the osteogenic factor(s) from the osteosarcoma cultures is an acid-soluble, non-dialyzable substance that interacts with collagen.

Animals↗
PubMed1978

Hypersensitivity pneumonitis with antibodies to Cryptococcus neoformans.

Clinical and immunological studies were made in forty-two patients diagnosed as suffering from hypersensitivity pneumonitis at Osaka Prefectural Habikino Hospital between 1973 and 1977. All the sera from forty-one patients tested had high titres of antibody against Cryptococcus neoformans in indirect fluorescent antibody tests, and twelve also had precepitins against Cryptococcus neoformans polysaccharide. Only about 10% of control sera from patients with other lung diseases had low titres of antibody against Cryptococcus neoformans. Antibody against Cryptococcus neoformans was also found frequently in the sera of asymptomatic members of the families of the patients. A possible relationship of Cryptococcus neoformans to hypersensitivity pneumonitis is suggested.

Adolescent↗
PubMed1978

Effect of age on C1q and C3 levels in human serum and their presence in colostrum.

The initiating complement component (C1q) in the classical pathway of 730 subjects and the first essential component (C3) in the alternative pathway of 461 subjects in Japan were examined. The study population consisted of normal healthy newborns, infants, children, adults and the old (from birth up to 75 years of age). In cord sera, both C1q and C3 were about 60% to the total mean level. At 3 days of age, C1q markedly increased to the mean level which remained relatively invariable up to 40 years of age. And above 40 years, the C1q level increased steadily with age up to about 75 years of age. C3 reached the mean level at about 1 month of age, and was highest during infancy. This level declined at about puberty and then continued to increase steadily with age up to around 55 years. In normal healthy subjects, a moderate positive rank correlation was found between C1q and C3 amounts. No significant differences of C1q and C3 levels were evident between male and female. No C1q was demonstrable in the colostrum from which lipids were previously removed, but after concentration by precipitation in a chelating agent with a low ionic strength, C1q, measured immunochemically, was detectable at concentrations of 300 ng/ml of colostrum. C3 was also detected at concentrations of about 200 microgram/ml of colostrum.

Adolescent↗
PubMed1977

Effect of methylnitrosocyanamide on cultured mammalian cells.

Effect of methylnitrosocyanamide (MNC) on a cultured mammalian cell line was examined in comparison with that of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). It was observed that MNC was about 3 times more potent than MNNG in the experiments on toxicity and inducibility of chromosome aberration and mutation. An increase in toxicity of MNNG was observed by minimizing the elevation of pH, while toxicity of MNC was more potent in the serum-free condition than in the presence of serum. Further, MNC was shown to be extremely rapid-acting, that is, 10 min was enough to exert its toxic effect.

Cell Division↗
PubMed1976

Development of two inbred strains of rats and characteristics of their skin reactions.

Two inbred strains of rat (Donryu and Sprague-Dawley strains) were developed. The skin reactions of these strains immunized with M. tuberculosis, hen egg albumin (OVA) or hen egg lysozyme and challenged with the purified protein derivative (PPD) or each antigen were even and uniform. The Donryu strain showed a typical Arthus reaction with petechiae and edema and a negligible delayed skin reaction, whereas the Sprague-Dawley strain showed a poor Arthus reaction and a typical delayed skin reaction with central necrosis and induration. The Arthus reaction or delayed skin reaction could be passively transferred to recipient rats of each strain by immune sera or sensitized peritoneal exudate cells (PEC), respectively.

Animals↗