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Biomedical subjects

A Taranta

Publications and source records attributed to A Taranta.

At least 55 records · Page 3Linked to original sources
PubMed1975

Host factors in the susceptibility of rheumatic patients to streptococcal infections.

In children and adolescents who each had at least one previous episode of rheumatic fever and who were not maintaining effective anti-streptococcal prophylaxis, the attack rates of subsequent streptococcal infections declined with advancing age, but were unaffected by gender, cardiac status, or multiplicity of antecedent rheumatic episodes. The rate of rheumatic recurrence per streptococcal infection fell with advancing age, but rose with increasing amounts of cardiac damage and with multiplicity of previous rheumatic attacks. The results suggest that the underlying clinical features of the host have a greater effect on the rheumatogenicity of an acquired streptococcal infection than on the ability to avoid the infection.

Acute Disease↗
PubMed1972

Isolation by electrofocusing of two lymphocyte mitogens produced by Staphylococcus aureus.

Staphylococcus aureus strain DA352, grown in a diffusate of Todd-Hewitt broth, produced two extracellular nondialyzable lymphocyte mitogens having isoelectric points of 5.5 to 5.7 and 8.6 to 9.0. The mitogens were separable from one another by isoelectric focusing and could be isolated free of detectable amounts of other staphylococcal products by ethanol precipitation followed by isoelectric focusing. Dose-response curves with both mitogens showed a maximum per cent transformation in the range (90%+) obtained with phytohemagglutinin (PHA), a decrease of transformation with excess mitogen, and, with decreasing concentrations, a slope somewhat less steep than that obtained with PHA. Incubation with undigested or pepsin-digested pooled human gamma globulin enhanced the activity of the basic mitogen.

Ammonium Sulfate↗
PubMed1969

Dissociation of hemolytic and lymphocyte-transforming activities of streptolysin S preparations.

The ability of streptolysin S preparations to induce high percentages of transformation in human peripheral blood lymphocytes was confirmed in a series of apparently healthy donors. Transforming activity was not demonstrated in the two media used for streptolysin S production, nor in control preparations in which a strain each of Streptococcus viridans, Staphylococcus aureus (nonhemolytic), and Diplococcus pneumoniae was substituted for the beta hemolytic streptococcal strain used for streptolysin S production. The relation of the hemolytic activity to the lymphocyte transforming activity of streptolysin S preparations was studied by means of inactivation and fractionation experiments. Heating produced a loss in both activities, but more in the hemolytic than in the transforming activity. The transformation obtained with a heated preparation had a high degree of correlation with that obtained with the unheated preparation in a series of normal subjects and patients with various rheumatic diseases, whose lymphocytes were often less responsive to stimulation with streptolysin S preparations (both heated and unheated) than the lymphocytes of the normal subjects studied. Treatment of streptolysin S preparations with chymotrypsin, vegetable lecithin, or trypan blue (the latter in minute amounts) resulted in preparations with no detectable hemolytic activity but with undiminished lymphocyte transforming activity. Chromatographic fractionations on DEAE-Sephadex columns yielded fractions endowed with transforming but not with hemolytic activity, and other fractions endowed with hemolytic but not with transforming activity. The recovery of the hemolytic activity was not complete and quantitation of the recovery of the transforming activity was not attempted. These experiments indicate that the hemolytic and transforming activities of streptolysin S preparations are independent of each other, and specifically that they are the attributes of two different streptococcal products, one of which is streptolysin S. The other is a nonhemolytic streptococcal product present in streptolysin S preparations but previously unrecognized. Some implications of these findings are discussed.

Blood Donors↗