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S Kitada

Publications and source records attributed to S Kitada.

50 records · Page 3Linked to original sources
PubMed1987

Gangliosides shed by tumor cells enhance tumor formation in mice.

The role of tumor cell membrane gangliosides in tumor formation was probed using a series of cloned murine AKR lymphoma cell lines. Tumor formation was directly related to high expression and shedding of membrane gangliosides. In vivo, as little as 1 pmol of purified total gangliosides of highly tumorigenic cells, injected intradermally with poorly tumorigenic cells (which lacked and did not shed gangliosides), markedly increased the tumorigenicity of these cells in syngeneic normal mice. Thus, gangliosides shed by tumor cells are a previously unrecognized, extremely potent enhancer of tumor formation in vivo.

AKR murine leukemia virus↗
PubMed1987

[The pharmacological properties of a new anti-allergic agent, KP-136, in cutaneous models].

The pharmacological properties of KP-136 were studied using cutaneous reactions in rats and guinea pigs. KP-136 remarkably inhibited the passive cutaneous anaphylaxis (PCA) with intravenous and oral dosing. However, the inhibitory effect of KP-136 had an apparent species difference. Thus, KP-136 was more effective on rat PCA than that of guinea pig. In four rat cutaneous reactions produced by three allergic reactions and compound 48/80, KP-136 was remarkably effective on two homologous PCA induced by IgE and IgGa. The intravenous and oral doses for 50% inhibition on the PCA were 0.2 mg/kg to 0.4 mg/kg and 0.5 mg/kg to 0.9 mg/kg, respectively. KP-136 was scarcely effective on cutaneous reactions elicited by intradermal injection of histamine and serotonin which are main chemical mediators in rat homologous PCA. However, KP-136 blocked the degranulation of mast cells and decrease of histamine content in skin elicited by the PCA. In addition, KP-136 showed a potent inhibition on the immunological release of histamine from rat peritoneal exudate cells. The concentration for 50% inhibition on the histamine release was 5 ng/ml. These findings indicate that KP-136 is an oral potent inhibitor on PCA, and it acts by blocking the release of chemical mediator(s) from mast cells.

Administration, Oral↗
PubMed1986

Tumorigenicity of T lymphoma/T lymphoma hybrids and T lymphoma/normal cell hybrids.

Stable hybrids formed between clones of established murine T-cell lymphoma lines, and between lymphoma clones and normal spleen or thymus cells were examined for their tumorigenic properties by intravenous (i.v.) and intradermal (i.d.) inoculation into syngeneic AKR mice. Fusion parents consisted of T lymphoma clones of high and low tumorigenicity derived from the SL 12 cell line. In addition, normal spleen cells and thymocytes were fused with poorly tumorigenic T-lymphoma clones. Hybrids tested by i.v. inoculation of 10(6) cells to syngeneic hosts showed that fusion between the lymphoma cells resulted in hybrids which displayed the phenotype of the highly tumorigenic parent. Also, it was shown that fusion of poorly tumorigenic lymphoma cells with normal spleen cells resulted in hybrids with enhanced tumorigenicity. Fusion of poorly tumorigenic lymphoma cells with normal thymocytes resulted in hybrids with the highest tumorigenic potential. The pattern of spread for the tumor/tumor hybrid was that of the highly tumorigenic parent. Tumor spread patterns for the spleen/tumor hybrids were different from those of the thymocyte/tumor hybrids. Intradermal inoculation of 10(5) cells from tumor/spleen or tumor/thymocyte hybrids revealed differences in latent periods between parental and hybrid cells, the tumor/thymocyte hybrids having the shortest latent period. Surface marker studies and T-cell antigen receptor mRNA determinations in the tumor cell/normal cell hybrids indicated that the normal parent was a cell of immature phenotype. Therefore, high tumorigenicity is a dominant characteristic, and poorly tumorigenic but "immortal" T lymphoma cells can derive characteristics which increase their in vivo growth capacity from the putative immature normal cells with which they selectively fuse.

Animals↗
PubMed1985

Conditions affecting clonal growth of lymphoma cells in a semisolid matrix.

This study demonstrated the importance of the methods used in determining the lymphoma cell colony stimulating activity of factors derived from lymphoma cells. The in vitro colony formation in a semisolid matrix of the AKR mouse lymphoma cell line, SL 12, and three cloned derivatives, SL 12.1, SL 12.3, and SL 12.4, was studied. We show that the use of soft agar or methylcellulose as a semisolid matrix results in colony formation by the lymphoma cells only in the presence of serum. The addition of conditioned medium (CM) from lymphoma cells growing in serum-free medium does not stimulate colony growth. However, when purified agarose is used, colonies grow in a dose-dependent manner in the absence of serum and in the presence of CM. These results indicate that the type of semisolid matrix used can influence results in studies of this nature. Purified agarose provides the best environment when colony formation by lymphoma cells is used to measure the presence of growth factors in test-conditioned media.

Agar↗
PubMed1985

Transferrin-like activity produced by murine malignant T-lymphoma cell lines.

Transferrin has been considered to be an essential requirement for hematopoietic cell proliferation in culture. We have isolated two cloned lymphoma cell lines, SL 12.1 and SL 12.4, which grow and adapt in serum-free medium without added transferrin. Antibody to the transferrin receptor blocks the growth of these cells. We have also demonstrated that transferrin-free conditioned medium from the cells will compete with transferrin for binding. Furthermore, conditioned medium from SL 12.1 and SL 12.4 cells induces and supports exponential growth of a transferrin-dependent lymphoma cell line, SL 12. We conclude that these two transferrin-independent cloned lines produce transferrin-like activity which plays a crucial role for cell proliferation.

Animals↗
PubMed1978

Liver and thymus lipid composition in AKR mice with and without lymphomas.

Lipid composition of liver and thymus in controls, early stage lymphoma, and advanced stage lymphoma-bearing AKR mice was studied. There was a significant decrease in the liver total lipid content in mice with advanced lymphoma, whereas in the early stages, no quantitative change was seen. In livers of mice with advanced stage lymphoma, there was a significant decrease in the nonpolar fraction. The decrease was in triglyceride, whereas the cholesterol fractions were relatively increased though hig,ly variable. There was an increase in the polar lipid/nonpolar lipid ratio in the advanced lymphoma livers and a very large increase in the polar lipid/triglyceride ratio, indicating that the decrease in total lipid in these livers was largely in the triglyceride fraction. Similar changes were seen in the thymus, in which the lipid composition reflected the transformation from normal to malignant cells.

Animals↗