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Biomedical subjects

Y Katoh

Publications and source records attributed to Y Katoh.

At least 289 records · Page 16Linked to original sources
PubMed1982

Higher efficiency of hamster hepatocytes than rat hepatocytes for detecting dimethylnitrosamine and diethylnitrosamine in hepatocyte-mediated Chinese hamster V79 cell mutagenesis assay.

The mutagenicities of dimethylnitrosamine (DMN) and diethylnitrosamine (DEN) on Chinese hamster V79 cells were examined by cocultivation of the cells with primary cultures of rat hepatocytes or hamster hepatocytes. Mutations in V79 cells were selected by resistance to ouabain. The mutation frequencies induced by all doses of DMN (1, 5, 10 and 50 micrograms/ml) and DEN (10, 50, 100 and 500 g/ml) were substantially higher on cocultivation with hamster hepatocytes than with rat hepatocytes. Thus it is proposed that hamster hepatocytes are useful for detecting mutagenesis in V79 cells induced by nitrosamines.

Animals↗
PubMed1982

Conversion of platelet-derived growth factor-dependent cells to growth factor-independent cells during chemical carcinogenesis in vitro.

The growth responses of hamster dermal fibroblasts (HDF cells) to platelet-derived growth factor (PDGF) during chemical carcinogenesis in vitro were investigated. Normal HDF cell grew in medium with whole blood serum (WBS), but not in medium with plasma-derived serum (PDS). However, they grew in PDS medium when PDGF was added. In contrast to control cultures which finally stopped proliferating, 7 out of 8 cell strains treated with 4-nitroquinoline-1-oxide (4NQO) or N-methyl-N'-nitro-nitrosoguanidine changed to cell lines. Later, 5 of these 7 cell lines became able to grow in PDS medium in association with ability to grow in soft agar. When clonal cell lines were isolated at early stages of carcinogenesis while parental cell lines were still PDGF-dependent, most of them gradually became PDGF-independent as well. Dialysed cell lysates of transformed HDF cells showed strong growth stimulating activity on normal HDF cells in PDS medium. Thus, this conversion of PDGF-dependent cells to PDGF-independent cells was correlated with the appearance of a growth factor(s) produced specifically by transformed HDF cells.

4-Nitroquinoline-1-oxide↗
PubMed1982

The light and electron microscopic localization of intracytoplasmic nucleolus-like bodies in the mouse brain stained by Holmes' silver method.

By light microscopic observation of the mouse brain impregnated by the Holmes' method, intensely stained cytoplasmic inclusion bodies were demonstrated in the nerve cells of the hypothalamus, locus coeruleus and other autonomic regions in addition to the limbic system and some circumventricular organs. Electron microscope observation of ultrathin sections made from vibratome sections impregnated by the Holmes' method revealed that the structures which have been called the nucleolus-like bodies were loaded with large amounts of gold particles. Hence, the Holmes-impregnated cytoplasmic inclusions could be identified with the so-called nucleolus-like bodies. The fine structure, distribution and significance of these bodies were described.

Animals↗
PubMed1982

[On the changes of Holmes positive intracytoplasmic bodies in the mouse locus coeruleus (author's transl)].

The intracytoplasmic inclusion bodies were found to be intensely stained in the normal nerve cells by the modified Holmes method (Katoh and Shimizu, 1982b). In the present study we used ddY mouse under normal and experimental conditions and stained locus coeruleus region, where the inclusion bodies are remarkably rich in number. The inclusion bodies stained by Holmes method were round in shape and 1--3 micrometers in size and were present singly or 2 in one cell. Total number of these bodies amounted to 1569 +/- 166 in the unilateral locus coeruleus in both sexes. Experimental conditions, such as dehydration for 3--6 days, fasting for 3--6 days, dehydration plus fasting for 3--6 days and reserpine (5 mg/Kg) administration markedly decreased the number of the bodies. However castration (10 to 30 days after operation) and vasopressin (2 IU each for 13 days) produced no changes. Nialamide (300 mg/Kg each for 3 days) caused slight increase. In the ontogenetic development the bodies already appeared in the late fetal life.

Animals↗
PubMed1982

[Fine structure of the locus coeruleus in the mouse (author's transl)].

The aim of this study is to clarify the fine structural organization of the mouse locus coeruleus (LC), which has not been thoroughly investigated yet, by a light and electron microscope. In a light microscopic study we used the wet fluorescent method and counted numbers of fluorescent LC cells and obtained 1326 +/- 64 in oneside, and many processes of LC cells reached and expanded into the latero-dorsal tegmental nucleus and nucl. parabrachialis medialis and lateralis. By EM study of glyoxylic acid and permanganate fixed material, LC cells (the principal cells, (16.8 +/- 2.9) X (27.8 +/- 5.1) micrometers), which contained small and large cored vesicles characteristic for NA, were divided into 2 types. The one was rich in Golgi apparatuses, ER and other cell organelles, the other being poor in these cell organelles. Another type of cells, devoid of cored vesicles, were small in size (12 X 15 micrometers) and poor in cell organelles. In the neuropil of LC, the % of axon terminals containing NA cored vesicles amounted to 2.2 (+/- 0.67) % of all axon terminals (a total of 10,545). Counted NA terminals (a total of 232) showed apposition to dendrites at 43%, free endings at 52%, contacts to LC cells at 5%. Moderate number of dendrites containing cored vesicles contacted with LC cell bodies or their dendrites especially in the caudal part of LC.

Animals↗
PubMed1981

The growth responses of hamster chondrocytes, dermal fibroblasts and embryo cells to whole blood serum and plasma-derived serum.

Autoradiographic studies with 3H-thymidine demonstrated that the growth responses of hamster chondrocytes, dermal fibroblasts and embryo cells, respectively, differed in media containing whole blood serum (WBS) and plasma-derived serum (PDS). Dermal fibroblasts seemed to require a growth factor from platelets for growth, but chondrocytes did not. Embryo cells showed an intermediate pattern of growth response to this factor.

Animals↗
PubMed1981

Cultured human bronchial epithelial cells: blood group antigens, keratin, collagens, and fibronectin.

Immunofluorescence and immunoperoxidase methods were used to identify constituents and products of cultured human bronchial epithelial cells and fibroblasts. Epithelial cells, but not fibroblasts, from patients with blood Types A or B reacted to the respective antisera to either the A or B blood group antigens. However, neither the epithelial cells nor the fibroblasts from patients with blood type O[H] reacted with the anti-H antisera. Epithelial cells in primary culture reacted with antibody to prekeratin proteins from human stratum corneum and fibroblasts did not react. Moreover, keratin filaments were assembled in vitro from proteins isolated from the epithelial cells. These immunological and biochemical data support previous morphological observations that human bronchial epithelial cells in primary culture shift progressively from a mucociliary epithelium to a keratinizing epithelium. Epithelial cells and fibroblasts could also be identified by their reactivity to anti-collagen antibodies. Fibroblasts reacted strongly with antibodies to Types I and III collagens and epithelial cells did not. On the other hand, epithelial cells reacted weakly with antibodies to Type IV collagen and fibroblasts were completely negative. Both epithelial cells and fibroblasts reacted with antibody to fibronectin; however, the distribution of fibronectin differed in the two cell types. In epithelial cells, fibronectin was restricted to the cell surface, whereas in fibroblasts it was found on the cell surface and in the extracellular matrix where fibrils of fibronectin were both cell associated and deposited on the surface of the dish where the fibroblasts had migrated.

ABO Blood-Group System↗
PubMed1981

In vitro transformation of hamster embryo cells by 3-(N-salicyloyl)amino-1,2,4-triazole.

The in vitro carcinogenic activities of 3-(N-salicyloyl)amino-1,2,4-triazole (SAT) and its two components, 3-amino-1,2,4-triazole and phenyl salicylate were examined in a transformation assay with cryopreserved hamster embryo cells. SAT induced morphological transformation at certain doses between 10 microgram/ml and 100 microgram/ml in each of 5 repeated experiments, but gave a negative result in the Salmonella mutation assay. 3-Amino-1,2,4-triazole also induced transformation in 3 repeated experiments. Phenyl salicylate did not induce transformation at any of the doses tested in 3 consecutive experiments.

Amitrole↗
PubMed1981

Morphological transformation, sister chromatid exchange and mutagenesis assay of betel constituents.

Betel quid, a masticatory widely used in Sri Lanka, consists of Jaffna tobacco, the nuts and leaves of betel plants and calcium hydroxide. An ethyl acetate extract of Jaffna tobacco induced morphological transformation of hamster embryo cells. The extract also induced sister chromatid exchanges inn virally transformed and phytohaemagglutinin (PHA)-stimulated human lymphocytes. The induction of sister chromatid exchanges was potentiated by addition of rat liver homogenate. The extract did not induce ouabain-resistant mutation of V79 cells. Extracts of betel nuts and leaves gave negative results in assay of morphological transformation, sister chromatid exchange and mutagenesis.

Areca↗
PubMed1981

Parathyroid hormone has a positive inotropic action in the rat.

Parathyroid hormone (PTH: synthetic bovine, amino terminus 1-34 amino acids) demonstrates a positive inotropic action on the isolated papillary muscle of the rat heart. The effect was evident at PTH concentration of 10(-12)M, and the maximum inotropic effect occurred with PTH concentrations greater than 10(-11)M. Biologically inactive PTH (PTH treated with H2O2) was without effect. The inotropic effect of PTH was partially blocked by propranolol and also suppressed in the papillary muscle of the rat pretreated with reserpine. Methoxyverapamil completely blocked the inotropic action of PTH. PTH was without effects on adenylate cyclase activity of the myocardium. Results show the presence of an inotropic action of PTH in vitro and suggest that this action of PTH is partially mediated by releasing the endogenous myocardial norepinephrine which exerts a positive inotropic effect via beta-adrenergic stimulation and by an increase in Ca++ influx across plasma membranes, but independent of adenylate cyclase activation. The inotropic action of PTH may be of significance in normal cardiac function.

Animals↗
PubMed1980

Morphological, growth, and chromosomal changes in bovine pancreatic duct epithelial cells exposed to N-methyl-N'-nitro-N-nitrosoguanidine.

Epithelial cells cultured from bovine pancreatic ducts were given a single treatment of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Multinucleated cells and giant cells were observed more frequently in carcinogen-treated cultures than in controls. The MNNG-treated cultures also contained a sizeable population of small, dense cells that were not observed in control cultures. At the concentration of 1.0 microgram/ml, MNNG caused an initial depression in the growth rate of the cells followed by growth stimulation for several weeks. The MNNG produced chromosomal damage in the cells as indicated by the observation that a substantial proportion of carcinogen-treated cells were heteroploid and contained a high frequency of metacentric and submetacentric chromosomes and a dicentric marker chromosome. The MNNG treated and control cultures did not acquire the ability to grow in soft agar or to produce tumors after transplantation into athymic, nude mice.

Agar↗
PubMed1980

Inhibition of mutagenesis in Chinese hamster V-79 cells by antioxidants.

The mutagenicity of benzo(a)pyrene (BP) on Chinese hamster V-79 cells cocultivated with X-irradiated hamster embryo cells was inhibited by phenolic antioxidants, such as tert-butyl-4-hydroxyanisole (BHA) and butyl-hydroxytoluene (BHT), but not by disulfiram and its related compounds such as tetraethylthiuram disulfide, diethyldithiocarbamic acid and dimethyldithiocarbamic acid. The mutagenicity of BP on V-79 cells was reduced 44% by BHA and 25% by BHT. BHA inhibited BP-induced mutagenesis, but not N-acetoxy-2-acetylaminofluorene (N-acetoxy-AAF)-induced mutagenesis. BHA is suggested to inhibit the mutagenic action of BP by altering its metabolism.

Animals↗