Search PubMed⌕ Search

Biomedical subjects

W Nakamura

Publications and source records attributed to W Nakamura.

At least 55 records · Page 3Linked to original sources
PubMed1981

[Effect of hyperthermia and methylprednisolone acetate on circulating thrombocytes in mice].

The effect of microwave-induced whole body hyperthermia and methylprednisolone acetate on the count of circulating thrombocyte in mice was investigated. Mice were heated at 43.5 degree C for 5, 10, 15 or 45 minutes with or without anesthesia. In all cases a high level of thrombocytosis was induced. Such effect was abolished by administration of methylprednisolone acetate 3 hours before heat treatment.

Animals↗
PubMed1981

Effects of hyperthermia on cell surface charge and cell survival in mastocytoma cells.

Changes in the structure of the surface of mastocytoma cells were induced by hyperthermia and were investigated by means of cell electrophoresis. A decrease in the cell electrophoretic mobility was detected as early as 15 min after treatment at 42 degrees and progressed more rapidly under hypoxic conditions than under oxic conditions. Subsequent recovery of electrophoretic mobility at 37 degrees was dependent on the length of heat treatment and oxygenation. The surviving fraction of cells detected by their colony-forming ability and the fraction of electrophoretically recovered cells 24 hr after exposure to hyperthermia showed a good statistical correlation. It was suggested that the mechanism of electrophoretic mobility reduction by heating was the vertical translocation of hyaluronidase-sensitive charge from the peripheral layer into a deeper layer by combined use of specific enzymes and stepwise different ionic strengths. These results suggest the importance of irreparable changes of membrane conformation in the loss of colony-forming ability of heated tumor cells.

Animals↗
PubMed1980

[Role of virus inhibitory factor or interferon in the antitumoral effect of whole-body hyperthermia].

The interferon inducing effect of hyperthermia was studied in normal and tumor-bearing mice. Circulating interferon was temporarily detected one day after subcutaneous transplantation of 1.6 X 10(6) Ehrlich's ascites tumor cells. Hyperthermia of 43.5 degrees C for 5 min did not induce the interferon formation in mice with or without subcutaneous tumor of the cells. These findings showed that the induction of interferon formation was not main cause of the hyperthermia-induced tumor inhibition.

Animals↗
PubMed1978

Radioprotective effect of 5-hydroxytryptamine and 5-hydroxytryptophan on mammalian cells irradiated in vitro.

The radioprotective effect in vitro of 5-hydroxytryptamine (5-HT) and 5-hydroxytryptophan (k-HTP) was studied with cultured mammalian cells of three cell lines: 5-HT-synthesizing FMA and 5-HT-non-synthesizing FM3A and B16-C2W. In these cells, the addition of 5-HT to the suspending medium induced only a weak protection or no protection at all. The increase in the 5-HT content of these cells at the time of irradiation was negligible. Pre-incubation of cells for 40 min in a 5-HTP-containing medium resulted in an elevation of the 5-HT content concomitantly with an increase in the radioresistance of FMA cells, where the DRF at 1 per cent was 1 x 8. In FM3A and B16-C2W cells such an effect was not observed. The same relationship between 5-HT content and radioresistance was also observed in FMA cells which were cultured in different densities or with reserpine. These results strongly suggest that the substance playing the main role in the induction of radioresistance in cells in vitro is the 5-HT that exists in the cells.

5-Hydroxytryptophan↗
PubMed1977

Cytoplasmic leucine naphthylamidase activity expressed in signet-ring cell carcinoma of the stomach.

Histochemical studies were performed on signet-ring cells in surgically resected gastric carcinomas from 64 patients. On the basis of periodic acid-Schiff reactivity of the intracellular mucin, the signet-ring cells were classified as type A (immature), type B (intermediate), or type C (mature). Different staining reactions to Alcian blue at pH 2.5 enabled type C cells to be subclassified as C-1 or C-2. In 63 cases (98.4%), intense leucine naphthylamidase (LNAase) activity was found histochemically in the cytoplasm of nearly all cancer cells except type C-2. Localization of LNAase activity in the cytoplasm was confirmed by conventional biochemical assay. From the present results, histochemical characteristics of signet-ring cell carcinoma are discussed.

Adenocarcinoma, Mucinous↗
PubMed1976

[Relative biological efficiency of neutrons (2 MeV) and X-rays for mastocytoma cell division capacity].

The effects of 2 MeV neutrons were compared with those of 200 kV X-rays for the criterion of lethality in mastocytoma cells of ascites type. The cells prepared as suspension were exposed to the radiations in vitro under aerobic condition and transplanted in the abdominal cavity of mice. Their viability was estimated according to the growing speed of the excreted amount of urinary 5-HIAA in the host animal. The RBE varied between a value of 3.1 at the 10 per cent level of cell survival to 1.8 for the mean lethal dose (Do).

Animals↗
PubMed1976

[Characteristics of a mastocytoma cell line adapted to in-vitro culture].

A cell line adapted to in vitro culture was obtained starting from ascites type mastocytoma cells which were maintained by successive transplantation in mice. The cells make colonies in liquid culture medium as well as on agar plate. In comparison under microscope and of behaviour in abdominal cavity of mice, no difference was detected between cells of this cell line and those of original one.

Animals↗
PubMed1976

Prediction of radiosensitivity of individual mice by multidimensional analysis.

Ten physiological indices on each mouse were measured before an exposure to ionizing radiation. The exposure of mice to 700R of X-rays induced 45% mortality within 30 days. A prediction of death or life of each mouse was done by a multidimensional quantification. The highest success rate of prediction was obtained by using all ten indices and it resulted in 74.1%. Accordingly, it was possible to predict death of individual mice exposed to a dose around LD50 (30) with a high rate of success. When one selected five indices out of the ten indices by some criterion, the success rate of prediction decreased to 67.1%.

Animals↗
PubMed1975

[Incapacity of 5-hydroxytryptophan to act against the depression of tumor-resisting power of host animal which is induced by whole body x-irradiation].

The effect of L-5-hydroxytryptophan (L-5-HTP) against the depression of tumor-resisting power in host animal, which is induced by a whole body x-irradiation of 500 R, was studied. Host animal and tumor cell used were LAF, hybrid mouse and mastocytoma cell, respectively. The i.p. injected dose of L-5-HTP was 6.25 mg per mouse, which is most effective for protecting mice from radiation-induced hematopoietic death. In the experimental conditions, the agent was not effective to prevent the radiation-induced depression of tumor-resisting power of the animal.

5-Hydroxytryptophan↗