Search PubMed⌕ Search

Biomedical subjects

S Toyoshima

Publications and source records attributed to S Toyoshima.

At least 181 records · Page 10Linked to original sources
PubMed1977

Isolation of glycopeptides from the lectin-stimulated human peripheral lymphocyte cell surface.

Three radioactive glycopeptides were isolated from human peripheral lymphocytes stimulated with Wistaria floribunda mitogen in the presence of D-[14C]glucosamine hydrochloride by mild trypsin digestion followed by gel filtration and preparative high-voltage paper electrophoresis. The carbohydrate compositions of these glycopeptides suggest that one has a sugar chain of the type found in serum glycoproteins, consisting of sialic acid, galactose, N-acetylglucosamine, mannose, and fucose in a molar ratio of 2:2:4:2:1, and the other two have sugar chains like those of mucins, consisting of sialic acid, galactose, and N-acetylgalactosamine in a molar ratio of 1 or 2:1:1. The results of enzymic degradation with purified glycosidases indicate that these sugar chains are similar in structure to their counterparts in human erythrocyte membranes.

Carbohydrates↗
PubMed1976

Antiinflammatory activity of some 2,3-dihydrobenzofuran-5-acetic acids and related compounds.

A series of 2,3-dihydrobenzofuran-5-acetic acids and related compounds was prepared as potential antiinflammatory agents. As measured by the carrageenan-induced edema method for the preliminary screening test, introduction of a methyl group alpha to the acetic acid function enhanced the antiinflammatory activity, and alpha-(7-chloro-2,2-dimethyl-2,3-dihydrobenzofuran)-alpha-methyl-5-acetic acid (13a) showed the most potent activity in this series.

Acetates↗
PubMed1975

Lectins from Wistaria floribunda seeds and their effect on membrane fluidity of human peripheral lymphocytes.

Two lectins were isolated from Wistaria floribunda seeds. One is a strong mitogen against human peripheal lymphocytes and has been purified in the previous paper (Toyo-Shima S., Y., Nakano K., Tonomura, A., and Osawa T. (1971) Biochemistry 10, 4457). The other, which is a strong hemagglutinin being devoid of mitogenic activity against normal lymphocytes, has been purified in this paper by affinity chromatography on a Sepharose 6B column followed by DEAE-Sephadex column chromatography. Both lectins were found to be glycoproteins and their molecular weights were estimated to be 136,000 for the equilibrium. The hemagglutinin is composed of four apparently identical subunits of a molecular weight of 35,000 and the mitogen is adimer of 32,000 molecular weight subunit. Binding experiments with 125-I-labeled W. floribunda mitogen revealed that the maximal incorporation of [6-3H]thymidine or 32-PO4 occurred when only 5.2% of the avaliable receptor sites on normal lymphocytes were occupied by the mitogen. Furthermore, the mobility of W. floribunda lectins as well as other lectins bound to the cell receptor sites of normal lymphocytes was determined by fluorescence polarization of fluorescein-labeled lectins. The mitogen lectins tested, have high mobility and Lens culinaris hemagglutinin, have high mobility whereas the nonmitogenic lectins, W. floribunda hemagglutinin, Sophora japonica hemagglutinin, and eel serum anti-H hemagglutin show relatively low mobility. However, W. floribunda hemagglutinin bound to neuraminidase-treated lymphocytes showed relatively high mobility in accord with the fact that this hemagglutinin exerted weak but definite mitogenic activity against neuraminidase-treated lymphocytes. The change of membrane fluidity upon binding of the lectins to normal lymphocytes was also measured by fluorescence polarization of fluorescent hydrocarbon, 1,6-diphenyl-1,3,5-hexatriene, embedded in the membrane. The mitogenic lectins, W. floribunda mitogen and L. culinaris hemagglutinin, increased the membrane fluidity upon binding to lymphocyte cell surface within 30 min, whereas the non-mitogenic lectins, W. floribunda hemagglutinin and S. japonica hemagglutinin, did not effect the membrane fluidity. We suggest that the increase of membrane fluidity is one of the common biochemical events in the earliest stage of lymphocytes transformation.

Binding Sites↗
PubMed1975

Mechanism of action of anti-influenza benzamidine derivatives.

Benzamidine derivatives exhibited a high antiviral effect in vivo against influenza virus strains A2/Adachi and B/Lee. The inhibiting properties of anti-influenza benzamidine derivatives on the virus-induced inflammation undoubtedly plays an important role in the clarification of the mechanism of action of these drugs.

Amidines↗
PubMed1975

Antitumor activity of amino acid derivatives in the primary screening.

Approximately 350 amino acid derivatives were synthesized and tested for antitumor activity in four tumor systems. The effect on life prolongation and tumor growth was examined using mouse leukemia SR-61, Ehrlich ascites carcinoma, ascites sarcoma-180, and rat ascites hepatoma (AH-60C). Among these 350 derivatives, 29 compounds were found to be significantly effective in prolongation of the median life-span and inhibitory effect on tumor growth in the primary screening. Among these 29 compounds, the following five compounds were found to possess potential antitumor activity: N-(2-Naphthalene)sulfonyl-DL-tryptophan (A-91), 2-naphthylaminomethyl-gamma-aminobutyric acid (A-144), N-ethylcarbaminomethyl-L-isoleucine (A-145), N-9-fluorenylacetyl-L-phenylalanine (A-192), and N-propionyl-L-valine (A-195). These five compounds were active in prolongation of the life-span of mice bearing Ehrlich ascites carcinoma and in the inhibition of the cell growth. Some of these amino acid derivatives inhibited biosynthesis of macromolecules, DNA, RNA, and protein, in tumor cells. These results suggest that the site of action of the five amino acid derivatives appears to result from the inhibition of macromolecules and another unknown mechanism.

2-Naphthylamine↗