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Biomedical subjects

G Sato

Publications and source records attributed to G Sato.

At least 145 records · Page 8Linked to original sources
PubMed1976

Cloned mouse mammary cell lines requiring androgens for growth in culture.

Clonally derived cell lines have been established from the mouse mammary tumor Shionogi carcinoma 115. Physiological concentrations of androgens markedly increase the growth rate and saturation density of these clones. The cells fail to grow in 1% fetal bovine serum-supplemented medium, but addition of 10-50 nM androstanolone or testosterone results in resumption of exponential growth. Some other androgens, but not estrogens or progesterone, stimulate growth of these cells. Steroid receptors can be isolated from the cells. In addition to their effect on growth, androgens also cause a marked alteration in the cell and colony morphology of the clones.

Androsterone↗
PubMed1976

The replacement of serum by hormones in cell culture media.

The replacement of serum by hormones in cell culture media. (Reemplazo del suero por hormonas en el medio de cultivo de células). Arch. Biol. Med. Exper. 10: 120-121, 1976. The serum used in cell culture media can be replaced by a mixture of hormones and some accesory blood factors. The pituitary cell line GH3 can be grown in a medium in which serum is replaced by triiodothyronine, transferrin, parathormone, tyrotrophin releasing hormone and somatomedins. Hela and BHK cell strains can also be grown in serum free medium supplemented with hormones. Each cell type appears to have different hormonal requirements yet it may found that some hormones are required for most cell types.

Blood↗
PubMed1976

Growth control of heterologous tissue culture cells in the congenitally athymic nude mouse.

A variety of heterologous mammalian cells were inoculated into nude mice and scored for tumorigenicity. The cells tested were from primary cell cultures, established cell lines of neoplastic origin, established cell lines of nontumor origin, and primary cell cultures transformed by oncogenic viruses. Regardless of the animal species of origin, every cell line that was tumorigenic in some other animal host and every cell line of neoplastic origin was tumorigenic in nude mice. Several tissue culture cells lines capable of indefinite growth in vitro failed to form tumors in nude mice, and the basis of this growth suppression was investigated. The findings suggest that the failure of an established cell line to form tumors in nude mice is an authentic response to host-mediated growth-regulatory signals.

Animals↗
PubMed1976

Age-dependent resistance of chickens to salmonella in vitro: phagocytic and bactericidal activities of splenic phagocytes.

The phagocytic and bactericidal activities to Salmonella pullorum (strain 9-25) or Salmonella senftenberg (strain 99D) were examined in chicken splenic phagocytes from 0-day-old to 2-month-old chickens. The phagocytic activity against S pullorum increased in splenic phagocytes from chickens older than 7 days, but significant changes in activity against S senftenberg were not observed during the experimental period. The bactericidal activity of splenic phagocytes against S senftenberg was higher than that of phagocytes against S pullorum during the same period. Increase of the bactericidal activity against S pullorum was observed with increasing age, but the activity of the splenic phagocytes from 0-day-old chickens against S senftenberg was similar to that of the phagocytes from 2-month-old chickens. Although delayed hypersensitivity was confirmed by delayed wattle reaction in 2-month-old chickens sensitized with living S pullorum, the sensitization did not markedly affect phagocytic and bactericidal activities.

Age Factors↗
PubMed1976

Relationship of cell growth behavior in vitro to tumorigenicity in athymic nude mice.

The serum requirements, anchorage requirements, saturation densities, and contact inhibition responses of a variety of mammalian cell lines were determined under uniform conditions. The serum requirement of both transformed and normal cells was a sensitive function of initial plating density. Cloning efficiency on irradiated mouse monolayers was found to be an invalid indicator of contact inhibition of growth, since most cell lines that failed to form visible colonies on cell monolayers nonetheless proliferated on these monolayers. When normal and neoplastic cells from a variety of sources were examined, none of the growth parameters that serve to define the transformed state in vitro correlated consistently with cellular tumorigenicity in athymic nude mice. It is concluded that the most reliable and physiologically meaningful assay for malignant transformation is, at present, cellular tumorigenicity in athymic nude mice.

Animals↗
PubMed1975

Failure of human cells transformed by simian virus 40 to form tumors in athymic nude mice.

Four individual lines and one subline of human cells, permanently established in tissue culture after infection with simian virus 40, failed to form tumors when inoculated into athymic nude mice. Under identical conditions, three established human cell lines of neoplastic origin and a spontaneously established human lymphocyte line formed tumors. Nude mice that failed to grow tumors from inocula of simian virus 40-transformed human cells, grew tumors from subsequent injections of authentic human cancer cells. Further efforts to demonstrate an immunologic basis for the growth suppression of human simian virus 40 transformants were also negative. The data suggest that the changes in morphology and in vitro growth behavior induced by the viral information are not sufficient for, or are only coincidentally related to, the neoplastic state.

Animals↗
PubMed1975

Control of ovarian cell growth in culture by serum and pituitary factors.

An ovarian cell line was developed that requires hormonal conditioning of the host for growth in vivo and that requires special factors for growth in vitro. It is necessary to prepare special culture media to demonstrate the effects of growth factors in vitro. To this end, methods were developed for removing from serum those essential factors required for the growth of ovarian cells in culture. Minimal growth occurred in medium containing fetal calf serum that had been passed through a porcelain filter. This method of depleting serum was replaced by a procedure involving passage through a carboxymethylcellulose column. Either pituitary extract or the eluate from the column restored growth in these depleted media. The eluate was more active than pituitary extract with regard to maximal growth enhancement. When the cells were incubated in the depleted media, viability, as measured by plating efficiency, decreased with incubation time. Either pituitary extract or the eluate from the column prevented such death of cells. Based on these findings, we postulate that the eluate contains both a survival factor and a growth-promoting factor for these ovarian cells, while pituitary extract contains only the survival factor.

Animals↗
PubMed1975

Enzootic occurrence of chloramphenicol-resistant Salmonella typhimurium var copenhagen in calf population.

Chloramphenicol (CP)-resistant Salmonella typhimurium var copenhagen was frequently isolated (44.1 to 76.7%) from dead, diseased, and healthy calves on 3 farms in 1973 in northern Japan. On 2 of the farms, CP-resistant salmonella appeared suddenly during an epizootic of salmonella infection, and persisted. Of 87 CP-resistant to tetracycline (TC), streptomycin (SM), and sulfonamides (SA), and the remaining 13 isolates from dead calves on a farm were resistant to TC, SM, SA, and kanamycin (KM). Resistance patterns of all CP-resistant isolates were transferred completely.

Animals↗
PubMed1974

Purification of a growth factor for ovarian cells from bovine pituitary glands.

The purification of a growth factor from bovine pituitary glands that controls the division of an ovarian cell line maintained in tissue culture is reported. Extraction of bovine pituitary glands at pH 4.5 followed by ammonium sulfate precipitation, chromatography on carboxymethylcellulose, and gel filtration on Sephadex G-50 gives yields of ovarian growth factor of about 7 mg/kg of glands. Contamination by other pituitary hormones was not detected. The preparation obtained has been characterized with respect to biological activity, molecular weight, and amino-acid composition. The implication of this growth factor in the development of ovarian tumors is discussed.

Amino Acids↗