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Biomedical subjects

T Takaoka

Publications and source records attributed to T Takaoka.

At least 91 records · Page 5Linked to original sources
PubMed1981

A sensitive new method for measurement of guanase with 8-azaguanine in bicine bis-hydroxy ethyl glycine buffer as substrate.

Serum guanase activity has been considered as a possible specific indicator of hepatocellular diseases. However, no suitable method is available for routine clinical determination of serum guanase activity. Conventional assay methods are troublesome and inaccurate, since guanine and 8-azaguanine, the substrates of the enzyme, are scarcely soluble in water so that it is not possible to prepare a stable substrate solution of sufficient concentration for use in assays. A new method was developed for assay of guanase activity by direct colorimetric determination of ammonia. In this method, bicine bis-hydroxy ethyl glycine (dotite bicine) buffer is used for preparation of a stable substrate solution and with a fixed concentration of substrate of sufficient strength serum guanase can be measured sensitively and reproducibly. This assay system could be used as a routine clinical laboratory test in the diagnosis of liver damage.

Aminohydrolases↗
PubMed1981

Clinical evaluation of measurement of serum guanase activity as a screening test of liver damage.

A new method was developed for assay of guanase activity by direct colorimetric determination of ammonia. In this method, dotite bicine buffer is used for preparation of a stable substrate solution and with a fixed concentration of substrate of sufficient strength serum guanase can be measured sensitively and reproducibly. This assay system could be used as a routine clinical laboratory test in the diagnosis of liver damage. GOT, GPT and guanase activities were found to be significantly elevated in patients with various liver disorders, and those with acute myocardial infarction with prominent congestion of the liver and also in CCl4- treated dogs. However, serum guanase activity was normal in patients with various other diseases, in those with acute myocardial infarction and in dogs with experimental myocardial infarction without liver damage, even when the serum GOT and GPT activities were increased. The GOT, GPT and guanase in the medium of rat hepato cytes culture with 5.0 mM CCl4 were elevated. These findings suggest that serum guanase activity is a more specific indicator of liver damage than serum GOT and GPT. The determination of serum guanase activity in patients without liver damage, even when their serum GOT and GPT levels elevated, might be useful as a screening test of liver damage.

Adolescent↗
PubMed1981

Clinical and experimental studies of the determination of serum guanase activity in acute myocardial infarction.

Serum guanase activity was measured by a new method using direct colorimetric determination of ammonia in 25 patients with acute myocardial infarction, 21 dogs with experimental myocardial infarction and 6 CCl4-treated dogs, and compared with serum GOT and GPT activity. We found normal serum guanase activity in patients with acute myocardial infarction and in dogs with experimental myocardial infarction without liver damage, even when the serum GOT and GPT activities increased. On the other hand, serum guanase and transaminase activities were elevated significantly in the patients with acute myocardial infarction who had prominent symptoms of cardiac failure and congestion of the liver and CCl4-treated dogs. These findings suggested that the serum guanase activity was more specific than serum GOT and GPT activity as an indicator of liver damage and determination of serum guanase activity in the patients with acute myocardial infarction might be useful in assessing the presence of liver impairment.

Aminohydrolases↗
PubMed1980

Establishment of tissue culture cell strains from normal fetal human liver and kidney.

Three cells strains of tissue culture were established from normal fetal human liver and kidney tissues. The rate of cell proliferation decreased with time after the primary culture. The cells were rarely subcultured, but the medium was renewed routinely twice a week. After 9 months of cultivation, the cells were found in both tissues to have abruptly begun to proliferate rapidly, but only in the group culture in the medium containing galactose and sodium pyruvate in place of glucose. No special treatment were given to these cultures, e.g. treatment with viruses, chemical carcinogens and others. The chromosome number was kept around diploid in the beginning but was shifted to hypotriploid after the establishment. The cell strain from liver consists of epithelial cells. The cell strains from kidney consist of mixed population of various kinds of cells. Doubling time of cells is about 33.4 hours in all of them, as determined by cinemicrography. This might be the first establishment of cell strains from untreated, normal human tissues.

Cell Division↗
PubMed1980

Neutralization of cytotoxicity of spermine on the proliferation of rat liver cells in tissue culture.

Cytotoxicity of spermine in tissue culture was found previously. To neutralize this toxicity, the addition of various high molecular weight substances and others was attempted in this paper, e.g. lysozyme, N-acetyl-D-glucosamine, chondroitin sulfate, poly-L-glutamic acid, bovine serum fractions V and VI, fetal calf serum, methyl cellulose, carboxymethyl cellulose, polyvinylpyrrolidone and others. Into the culture of rat liver cells, strain RLC-10(2), simultaneous addition of other substances with spermine did not neutralize the toxicity. However, by the pretreatment of spermine with fetal calf serum or bovine serum albumin (fraction V) at 37 degrees C for 24 hr, the toxicity of spermine was markedly reduced. This was probably due to the denaturation of spermine caused by the pretreatment.

Animals↗
PubMed1980

An attempt in tissue culture at preventing and treating the collagen fiber formation of liver cells.

To prevent and to cure liver cirrhosis, we examined the effect of the ethanol extract of berries of Japanese ampelopsis on the collagen formation of rat liver cells in tissue culture. These cells had been transformed to produce collagen fibers very actively. When added at a time of subcultivation, the extract prevented the formation of collagen fibers. When it was added after the formation of collagen fibers, the fibers were fragmented into fine microfilaments.

Animals↗
PubMed1979

Tapping culture--an improved method for cell suspension culture.

A new culture vessel was designed for cell suspension culture. A silicone-covered magnet bar fixed by one end to the side wall of the bottle was held horizontally a short distance from the bottom. A standard type magnetic stirrer was used. In contrast to the conventional horizontal movement of "stirring" in cultures the bar moves vertically with a "tapping" motion. This improvement resulted in less cell injury, higher rate of cell proliferation and formation of fewer bubbles than in the conventional type. Nine cell types were simultaneously cultivated in tapping, stirring and stationary culture. All cell types proliferated more luxuriously in tapping cultures then in stirring cultures. Serial cultivation of cells in tapping cultures was also successful.

Animals↗
PubMed1979

Carcinogenesis in tissue culture 30: malignant transformation of normal rat liver cells treated with diethylnitrosamine in tissue culture with special reference to the differential effects of cytochalasin B on various cells with and without tumorigenicity.

Liver tissue of a suckling rat was cultured. After 3 weeks of cultivation, the cultures consisting of epithelial cells were treated with 50 micrograms/ml or 100 micrograms/ml DEN for 7 days. 5 months after the treatment, the mode of chromosome number was found decreased from 42 to 40 in the 100 micrograms/ml DEN-treated group and shifted to triploid range after 21 months. The mode in the 50 micrograms/ml DEN-treated group maintained the diploid number until the 5th month but was found reduced to 40 in 21 months. On subcutaneous backtransplantation into young rats at the 22nd month, the treated cells produced tumors at the site inoculated in all the rats. Metastatic foci were also detected in lungs. These tumors were histologically diagnosed as hepatomas. Untreated control cells did not produce tumors. The differential effects of cytochalasine B on the cells with and without tumorigenicity were examined by the use of these cells and other cells, and it revealed that the capacity of multinucleated cell-formation by cytochalasin B fairly corresponds with the backtransplantability of the cells. Binucleated cell formation, not more than 2 nuclei, in the culture of normal cells was found by time-lapse cinemicrography to be not due to the non-capacity of multinucleation but to the destruction of multinucleated cells.

Animals↗
PubMed1978

Pedigree analysis of the hypothermal recovery of the effects of gamma-rays on hepatoma cells.

Cultured hepatoma cells of the rat were irradiated with 400 to 900 R of gamma-rays. They were kept at room temperature for several hours before transferred to normal culture condition at 37 degrees C. The pedigree analysis of growing cells recorded by cinematography indicated a variety of lethal and non-lethal recovery events such as a decrease in lethal branch formation and an increase in locomotion. The so-called repair immediately after irradiation has many facets depending upon dose and duration of the low temperature treatment.

Animals↗
PubMed1977

Establishment of epithelial cell lines from rat glandular stomachs.

Nine epithelial cell lines were isolated from glandular stomach cells of fetal and suckling JAR-2 rats after the elimination of mesenchymal cells by mechanical and colonial isolation methods. Those cells have been proliferating continuously in a typical pavement-like arrangement. In early cultures a part of focal monolayers of small epithelial cells died simultaneously ("contact death"). The cells of three lines (RGS-2,RGS-5 and RGS-8) formed hemicysts when incubated for several weeks without subcultivation. Addition of But2cAMP and theophilline into culture medium enhanced the hemicyst formation by RGS-8 cells. Some evidence suggested that those three lines were originated from mucous epithelium of rat glandular stomach. These epithelial cell lines would be useful in the study of chemical carcinogenesis in culture.

Animals↗
PubMed1976

Kinetics of microcolonies of cultured mammalian cells after bleomycin treatment.

Cultured ascites hepatoma cells of the rat were treated with 400 to 900 R of gamma rays or 25 to 100 mug/ml of bleomycin for 30 min. The cells were followed up for 133 hr and the pedigrees were analyzed. Gamma rays and 2 low doses of bleomycin gave rise to typical reproductive death in generations 1 and 2 but 100 mug of the drug produced frequent interphase death. Natural death and induced death did not follow statistical randomness suggesting an existence of weak and sensitive clones in a population.

Bleomycin↗
PubMed1976

Carcinogenesis in tissue culture 27: heterotransplantation as an alternative in vivo assay for neoplastic state of cells in culture.

Cells of serially cultured strains and newly-isolated cells originating from rat liver and lung were heterotransplanted into pouches of golden hamsters treated with antithymocyte serum (ATS). The "take" was determined by histopathological examination of nodules formed by 3 weeks after the transplantation. The results obtained under this criteria showed that 9 of 11 cell strains backtransplantable to rats and 2 of 4 strains untransplantable were in parallel with those in rats. Three kinds of uncultured liver cells resulted in "no take".

Animals↗
PubMed1976

Carcinogenesis in tissue culture 26: malignant transformation of rat liver cells in vitro associated with paradoxical electrokinetic changes.

Periodical examinations of the electrophoretic mobility of rat liver cells of two culture strains, RLC-10(2) and JTC-25.P3, were performed after the treatment with 3.3 X 10(-6) M 4-nitroquinoline 1-oxide (4NQO) for 30 min in culture. As early as 47th day after a single treatment with 4NQO, both control and treated cells of RLC-10(2) were found to produce tumors in animals on back-transplantation. At this stage, however, little difference was yet observed in electrokinetic patterns between the treated cells and the original antecedent cells. In contrast, a subline, JTC-25.P3, treated twice with 4NQO under the same conditions demonstrated a malignant electrokinetic pattern resembling that of rat ascites hepatocarcinoma strains, although its tumorigenicity was not verified. These discrepancies between changes of electrokinetic pattern and tumorigenicity were discussed with special references to the antigenic difference between cultured cell strains and each original host rats.

Antibodies, Neoplasm↗