Biomedical subjects

K Sakita

Publications and source records attributed to K Sakita.

5 recordsLinked to original sources

PubMed1999

Underdevelopment of fetal thyroid follicular cells in athymic nude mouse (BALB/cAnNCrj-nu/nu) observed by electron microscopic morphometry.

Fetal thyroid follicular cells of congenitally athymic nude mouse (BALB/cAnNCrj-nu/nu) were studied with an electron microscope. The area of the entire cell, nucleus and mitochondrion were measured and compared in athymic and euthymic fetal nude mice (BALB/cAnNCrj-nu/+) at 18 days of gestation. The mean area of cytoplasm was significantly smaller in homozygous athymic nude mice than in heterozygous euthymic ones. The mean area of the mitochondrion was also smaller in homozygous athymic nude mice, but the difference was not statistically significant. There was no significant difference between the two groups in the area of the nucleus. These findings suggest that the thyroid gland of athymic nude mice is still underdeveloped at the end of gestation as compared to that of their euthymic littermates.

Animals↗

PubMed1997

In vitro cytotoxicity of imidazolyl-1,3,5-triazine derivatives.

We examined in vitro cytotoxic activity of imidazolyl-1,3,5-triazine derivatives using human breast cancer cell lines (MCF-7, R-27, T-47D and ZR-75-1) and murine leukemia cell line (P388). The percentage of viable cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazorium bromide (MTT) assay. Hexamethylmelamine (HMM), a 1,3,5-triazine derivative has previously been recognized as an antitumor agent effective against lung, ovarian and breast cancer, but failed to show a significant cytotoxic activity in the present study. In contrast, four imidazolyl-1,3,5-triazine derivatives, 2-(1-imidazolyl)-4,6-bis(morpholino)-1,3,5-triazine, 2-(1-imidazolyl)-4-morpholino-6-(3-thiazolidinyl)-1,3,5-triazine, 2-(4-cyano-4-phenylpiperidino)-4-(1-imidazolyl)-6-morpholino-1,3,5-triaz ine and 2-(1-imidazolyl)-4-(N-methyl-N-phenylamino)-6-morpholino-1,3,5-triazine showed cytotoxic activity for most cell lines, which was significantly greater than the activity of hydroxymethylpentamethylmelamine (HMPMM), a major metabolite of HMM.

Altretamine↗

PubMed1997

Structure and function of the hemolymph node in rats.

Hemolymph nodes (HLs) are unique lymph nodes, in that their lymphatic sinuses contain numerous erythrocytes. In this study, we compared the internal structure and immunologic function of HLs with those of ordinary lymph nodes (OLs) and the spleen. Electron microscopy revealed erythrocytes passing through the walls of blood vessels in the intermediate sinus area (IMSA) of a HL between expanded endothelial cell junctions. However, no direct communication was found between lymphatic sinuses and blood vessels. Numerous carbon particles appeared in the IMSA of HLs on 5 days after intravenous carbon particle injection, while OLs lacked particle deposition. Immunohistochemical studies showed that lipopolysaccharide (LPS) reached the IMSA of HLs and extravasated into medullary cords 4 hours after intravenous LPS injection, resulting in the appearance of more IgM-stained lymphocytes in the IMSA of HLs than in that of OLs on day 5. The ability of organs to produce antibodies was determined by counting the number of plaque forming colonies after intravenous injection of sheep red blood cells (SRBC). The HLs antibody-producing ability was between that of OLs and the spleen. These results suggest that HLs possess functionally open blood vessels in the IMSA and their immunologic capability is between that of OLs and the spleen. These findings suggests that HLs are lymphoid organs that have characteristics between those of the OLs and the spleen, both ultrastructurally and functionally.

Animals↗

PubMed1996

Morphometric study on the fetal thyroid gland in the nude mouse (BALB/cAnNCrj-nu/nu).

Fetal thyroid glands of athymic nude mice (BALB/cAnNCrj-nu/nu) were examined morphometrically on day 18 of gestation. Compared to euthymic litter mate controls (BALB/ cAnNCrj-nu/+), both the cell height and diameter of thyroid follicles were significantly smaller; fewer well-developed follicles were found in the peripheral region of the thyroid; the body weight and total volume of the thyroid gland were also smaller in nude mice. These results suggest underdevelopment of the fetal thyroid gland of the athymic nude mouse.

Animals↗

PubMed1993

Influence of adrenalectomy on the developing rat thymus during peri-weaning period.

Adrenalectomy of 17-, 18- and 19-day-old male and female rats did not cause any changes in the weight of thymus 4 days later. Adrenalectomy on day 20 of age induced a significant hypertrophy of the thymus 4 days later. These results indicate that on day 20 of age, just before weaning, the thymus is under some inhibitory regulation by the adrenal gland.

Adrenal Glands↗