Biomedical subjects
Publications and source records attributed to M A MADOFF.
Purified staphylococcal alpha-hemolysin (but not the toxoid) was demonstrated on the surface of rabbit and human erythrocytes by immunofluorescence. This occurred during the period of maximal hemolysis and was a transient event. These findings have been analyzed in relation to previous data on the kinetics of leakage of both small and complex molecular constituents of the erythrocyte.
Cooper, Louis Z. (New England Center Hospital, Boston, Mass.), Morton A. Madoff, and Louis Weinstein. Hemolysis of rabbit erythrocytes by purified staphylococcal alpha-toxin: I. Kinetics of the lytic reaction. J. Bacteriol. 87:127-135. 1964.-The hemolytic activity of purified staphylococcal alpha-lysin was found to be directly proportional to toxin concentration and inversely related to the log concentration of rabbit erythrocytes. Activity was directly proportional to the duration of lysin-red cell incubation until inactivating effects of heat and dilution became significant; this linear relationship was prolonged by incubation at a lower temperature and addition of bovine serum albumin. Study of the time course of hemolysis at different alpha-lysin concentrations revealed a family of sigmoid curves characterized by a prelytic lag phase and a period of rapid linear release of hemoglobin. The duration of prelytic lag varied inversely with the quantity of toxin, but the rate of hemolysis was directly proportional to toxin and red-cell concentrations. The presence of bovine serum albumin decreased the prelytic lag, prolonged the linear phase of the reaction, and increased total hemolysis. In the range of 25 to 46 C, the prelytic lag period became shorter with increase in temperature; at 48 to 52 C, it was markedly prolonged and hemolysis was strikingly diminished. As the incubation temperature was increased from 25 to 52 C, there was a decrease in the degree of maximal hemolysis, presumably due to thermal inactivation of alphalysin. The rate of hemolysis, when measured to 50% hemolysis, was optimal between 34 and 42 C but, when determined to the 10% level, was greatest between 40 and 46 C. The features of the hemolytic reaction suggest that staphylococcal alpha-toxin has the characteristics of an enzyme.
Cooper, Louis Z. (New England Center Hospital, Boston, Mass.), Morton A. Madoff, and Louis Weinstein. Hemolysis of rabbit erythrocytes by purified staphylococcal alpha-toxin. II. Effect of inhibitors on the hemolytic sequence. J. Bacteriol. 87:136-144. 1964.-Study of the time course of hemolysis of rabbit erythrocytes by purified staphylococcal alpha-lysin revealed that the specific toxin-red cell reaction occurs during the prelytic period. This reaction could be prevented or decreased by alpha-lysin antitoxin added early, but not by antitoxin added at the end of the prelytic phase or at any time thereafter. In contrast, hemolysis is suppressed temporarily by sucrose and permanently by polyethylene glycol, even when these are added during the period of rapid release of hemoglobin. When sucrose is present together with alpha-lysin and red cells only during the prelytic period, and when the cells are then washed and resuspended in phosphate-buffered saline, their subsequent hemolysis is not altered by the presence of the sugar. This is not so when antitoxin is employed. When erythrocytes are laked by a measured excess of alpha-lysin, only a portion of the original hemolytic activity can be recovered. Repeated exposure of lysin to red cells produces a loss of activity represented by a linear function when logs of residual activity are plotted sequentially. Once alpha-lysin has reacted with red cells, it does not appear to be available for attachment to other erythrocytes.
Madoff, Morton A. (New England Center Hospital, Boston, Mass.), Louis Z. Cooper, and Louis Weinstein. Hemolysis of rabbit erythrocytes by purified staphylococcal alpha-toxin. III. Potassium release. J. Bacteriol. 87:145-149. 1964.-The reaction between staphylococcal alpha-toxin and erythrocytes was characterized by rapid release of K(+) from the cells, early in the prelytic period; 50 to 75% of this loss occurred before leakage of hemoglobin was detectable. The addition of specific antitoxin early enough in the reaction to inhibit gross hemolysis also inhibited cation release. The presence of sucrose or polyethylene glycol prevented hemoglobin release, but was without effect on K(+) leak. These observations suggest that K(+) loss is a more specific indication of the progress of the reaction between alpha-toxin and erythrocytes than is the release of hemoglobin.
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Madoff, Morton A. (New England Center Hospital, Boston, Mass.) and Louis Weinstein. Purification of staphylococcal alpha-hemolysin. J. Bacteriol. 83:914-918. 1962. - Staphylococcal alpha-toxin has been purified by metal-ion precipitation, column chromatography, and continuous-flow paper electrophoresis. The resultant preparation is highly unstable. A single line is obtained on agar-gel diffusion analysis against staphylococcal antiserum. Two bands, both associated with hemolytic activity and migrating cathodally at pH 8.4, are obtained on starch-gel electrophoresis. Levels of lytic, dermonecrotic, and lethal toxin activity maintain a constant relationship in the crude and purified materials, suggesting the unity of these effects.
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