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Biomedical subjects

I Kato

Publications and source records attributed to I Kato.

At least 613 records · Page 34Linked to original sources
PubMed1982

Effects of diphtheria toxin and other exotoxins on oxidant generation by human and murine phagocytes.

Bacterial exotoxins such as diphtheria toxin (D.T.), staphylococcal alpha toxin and Leucocidin can powerfully activate granulocytes and macrophages as detected by production of chemiluminescence in presence of Luminol. Production of superoxide by granulocytes and of prostaglandin E2 in macrophages is also stimulated by D.T. In contrast with the known resistance of rodent parenchymal cells to the diphtheria toxin, human and rodent leucocytes have similar sensitivities to D.T.

Animals↗
PubMed1982

Mode of action of staphylococcal leukocidin: effects of the S and F components on the activities of membrane-associated enzymes of rabbit polymorphonuclear leukocytes.

The cytotoxic action of the S component of leukocidin from Staphylococcus aureus on rabbit polymorphonuclear leukocytes was supported by the following observations, (i) Leukocytes displayed a large chemotactic response to the S component (10(-10) M) as well as to the chemotactic factor N-formylmethionylleucylphenylalanine (10(-11) M). (ii) The S component stimulated high levels of phospholipase A2 activity in the cell membranes, with concomitant synthesis and release of prostaglandins. (iii) Uptake of 45Ca into leukocytes exposed to the S component was about double the rate of uptake into untreated cells. The increased 45Ca uptake into the cells was not inhibited by trifluoperazine and ruthenium red. (iv) Indomethacin and alloxazine, which had no effects on the binding of the S component to the cells, attenuated markedly the stimulation of phospholipase A2 activity, the syntheses of prostaglandins, and the increased uptake of 45Ca caused by the S component. The F component of leukocidin, bound to rabbit leukocytes with the aid of the S component, rapidly induced complete release of 86Rb from preloaded leukocytes. This release resulted from stimulation of ouabain-insensitive (Na+ + K+)-adenosine triphosphatase activity and inhibition of cyclic AMP-dependent protein kinase.

Animals↗
PubMed1982

Increased urinary excretion of angiotensin converting enzyme in patients with renal diseases.

We measured the activity of angiotensin converting enzyme (ED 3.4.15.1) in urine samples from normal subjects and patients with nephrotic syndrome and chronic glomerulonephritis. Urinary excretion of angiotensin converting enzyme in patients with nephrotic syndrome (1.58 +/- 0.50 (SD) units/day; n = 15) and chronic glomerulonephritis (1.01 +/- 0.45 units/day; n = 12) was significantly increased compared with normal subjects (0.38 +/- 0.10 units/day; n = 18). It was demonstrated that a high molecular weight form of the enzyme (more than 400000) was mainly excreted in urines from patients with nephrotic syndrome. After trypsin treatment, this form was altered to a low molecular weight form (290000). These two different forms of urinary angiotensin converting enzyme were compared with the enzyme purified from human kidney, and found to be identical with respect to Km values (2 mmol/l), pH optimum (pH 8.3), chloride ion dependency (0.8 mol/l), inhibitory effect of captopril (I50, 21 nmol/l), and behavior towards antiserum to human kidney angiotensin converting enzyme.

Adolescent↗
PubMed1981

Mode of action of staphylococcal leukocidin: relationship between binding of 125I-labeled S and F components of leukocidin to rabbit polymorphonuclear leukocytes and leukocidin activity.

The binding of (125)I-labeled S component to rabbit polymorphonuclear leukocytes was found to be concentration dependent and saturable at 37 degrees C. Scatchard analysis of the binding curve gave a straight line, indicating that S component binds to a single population of sites. The dissociation constant, K(D), derived from the Scatchard plot was 5.57 x 10(-9) M, and the number of binding sites per leukocyte was calculated to be approximately 5,300. Unlabeled S component (10(-8) M) or subunit B of cholera toxin (10(-7) M) readily competed with (125)I-labeled S component binding, and the labeled S component, preincubated with ganglioside G(M1) at equimolar proportions for 5 min, lost the binding capacity to the leukocyte membranes. The binding number of (125)I-labeled F component to leukocidin-sensitive cells, such as rabbit polymorphonuclear leukocytes and the established human myelocytic leukemia cells, in the absence and in the presence of the unlabeled S component (2.1 nM), was calculated to be 50 and 1,300 molecules per cell, respectively. This increased binding of the labeled F component was time and temperature dependent. The binding number of labeled F component to other cell types comparatively insensitive to leukocidin, such as erythrocytes, adipocytes, intestinal cells, and HeLa cells, was calculated to be less than 50 molecules per cell in spite of the sufficient amount of unlabeled S component bound to their cells. These observations are consistent with the view that in rabbit leukocyte the S component, preferentially bound to the cell surface at 5,300 molecules per cell, contributes to enhance the F component binding up to about 1,300 molecules per cell and may thus play a role of synergistic action of both leukocidin components on the cell membranes in the leukocytolysis.

Adipose Tissue↗
PubMed1981

Effects of proteases on the structure and activity of Pseudomonas aeruginosa exotoxin A.

The effects of various proteases on the enzymatic or biological activity and structure of exotoxin A from Pseudomonas aeruginosa were systematically studied. The toxin was extremely resistant to treatment with various enzymes. The lethality of the toxin disappeared upon treatment with P. aeruginosa protease and elastase, thermolysin, and trypsin with a long incubation time (5h) in the presence of a high enzyme concentration (molar concentration of enzyme to toxin, 1:10 or 1:20), but was little altered by either alpha-chymotrypsin or subtilisin. The decrease of adenosine diphosphate ribosylation activity was moderate when the same treatment was used, regardless to the protease source, except in the case of papain, which was tested in the presence of reducing agents. The increase in activation of the treated toxin determined in the presence of a denaturant and a reducing agent was less than that of the intact toxin, except in the case of trypsin. The differences in disc and sodium dodecyl sulfate gel electropherograms of the toxins treated with these proteases, except for those treated with papain, suggested that the toxins had been nicked by the protease, which resulted in their degradation by sodium dodecyl sulfate treatment. Papain degraded the toxin into fragments and caused the disappearance of lethality or a marked decrease of adenosine diphosphate ribosylation activity.

ADP Ribose Transferases↗
PubMed1981

Chemical analysis of glycosaminoglycans inhibiting DNA synthesis.

Sulfated glycosaminoglycans having inhibitory activity in cellular and subcellular systems were found in some tumor tissues from humans. These glycosaminoglycans inhibited more efficiently DNA synthesis of virus transformed cells (SV40-WIRL-3 cells) than their parent normal cells (WIRL-3 cells). Sulfated glycosaminoglycans found in normal human and non-tumor tissues did not have as high an inhibitory activity on DNA synthesis by cells used in this investigation as those from some human tumor tissues. The former did not inhibit as effectively DNA synthesis by virus transformed cells, as DNA synthesis by their normal parent cells. The monosaccharide composition of these sulfated glycosaminoglycans showed N-acetyl glucosamine (Glu-NAc) as a main monosaccharide, and xylose (Xyl), glucose (Glu), galactose (Gal), hyaluronic acid (Hu-A) as minor monosaccharides. N-acetyl galactosamine was not detected.

Adult↗
PubMed1981

Antitumor activity of Lactobacillus casei in mice.

The effect of Lactobacillus casei YIT 9018 (LC 9018) on the growth of transplantable allogeneic and syngeneic mouse tumors was studied. Intraperitoneal treatment of LC 9018 caused a significant prolongation of the life span of ICR mice inoculated with sarcoma-180 intraperitoneally and BDF1 mice inoculated with L1210 leukemia intraperitoneally. Intravenous injection of LC 9018 markedly inhibited the growth of subcutaneously inoculated sarcoma-180. This organism was also effective against methylcholanthrene-induced syngeneic MCA K-1 tumor in BALB/c mice. The antitumor activity of LC 9018 was reduced by treatment with carrageenan, an anti-macrophage agent, and was also observed in T-cell deficient athymic nude mice. These results suggested that the antitumor activity of LC 9018 may be macrophage-dependent.

Animals↗