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Biomedical subjects

J Sawada

Publications and source records attributed to J Sawada.

At least 127 records · Page 7Linked to original sources
PubMed1977

Morphological microassay and kinetics of the cytotoxicity of guinea pig lymphotoxin.

The kinetics of guinea pig lymphotoxin (GLT)-cytotoxicity on three L cell sublines were studied in detail by a micromethod using morphological distinctions between intact cells and dead cells. The reduction of the intact cell number and increase of the dead one concurrently occurred after a lag time, its length depending upon the GLT concentration ([GLT]). Although different patterns of the changes in the survival ratio (S) were discerned with different sublines, under appropriate conditions, --ln S was proportional to [GLT] and the reciprocal of the initial target cells number. Furthermore, it was shown that the S value at 24 hr was dependent upon the absolute amount of GLT.

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PubMed1977

The effect of pulse treatment of target cells with guinea pig lymphotoxin and the nature of its binding to target cells.

In order to investigate the binding of guinea pig lymphotoxin (GLT) to target cells, the reduction of survival ratio (S) after the pulsed exposure of target cells to GLT at 4 degrees C and subsequent incubation at 37 degrees C for 24 hr was examined in detail. The dose response of GLT, and the relation between the S value and the length of pulse treatment demonstrated the saturation and equilibrium of the GLT-binding. It was also shown that the GLT once bound to the target cells dissociated very slowly. Several sugars possessing a terminal beta-galactosyl residue had an inhibitory activity against the effect of pulse treatment. This suggests that GLT binds to receptors on the target cell surface, probably glycoproteins having beta-galactosyl residues as terminal sugar residues. The trypsin treatment of GLT-pulsed target cells restored survival ratios and this restoration was dependent upon the time of trypsin treatment. This suggests that the stage of the association of GLT to target cells changes from trypsin-sensitive into trypsin-insensitive.

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PubMed1977

[Lymphokines].

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Animals↗
PubMed1976

Isolation of a new polyether antibiotic, lonomycin.

A new polyether antibiotic, lonomycin, was isolated from the culture of Streptomyces ribosidifcus strain TM-481. The antibiotic obtained as a sodium salt is a colorless prism having a molecular formula of C44H75O14Na(M.W. 850), m.p. 188 approximately 189 degrees C, and has no absorption maxima in the ultraviolet region. The infrared and NMR spectra of the antibiotic suggest the presence of a carboxyl and four methoxyl groups. Lonomycin shows antimicrobial activity against gram-positive bacteria.

Animals↗
PubMed1976

Cytotoxic activity of purified guinea pig lymphotoxin against various cell lines.

Cytotoxic activity of the purified guinea pig lymphotoxin (GLT) was tested on various blood cells and various cultured cell lines. GLT was generally ineffective on erythrocytes and lymphocytes, but it was somewhat effective on peritoneal exudate cells indicating GLT might play an important role in the regulatory mechanism of the cellular immunity. Considerable difference in target cell sensitivity was observed among the cultured cell lines tested. The sensitivity of L cells to GLT was significantly lowered by the trypsin treatment of the cells. Furthermore, porcine thyroglobulin glycopeptide exerted weak but definite inhibitory activity against GLT. These results suggest that the cytotoxicity of GLT might be triggered by the binding of GLT to the receptor sites of glycoprotein nature on the cell surface.

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