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M BOVARNICK

Publications and source records attributed to M BOVARNICK.

10 recordsLinked to original sources
PubMed1960

An adenosine-triphosphate-activated hemolytic system. III. Effect of rabbit hemolytic factor on the membrane permeability of human red cells.

Lysis of human red cells in vitro by an enzyme obtained from rabbit red cell hemolysates and the inhibition of this lytic activity by human stroma have been shown to require Mg(++) and ATP, and ATP utilization has been demonstrated in both reactions. We find that sodium or potassium ions are also required for the lytic phenomenon and that they enhance the inhibition. The rate of hemolysis is not affected by the internal concentrations of these ions but depends only on the external concentration. The rate of influx and efflux of Na(22)Cl and K(42)Cl in surviving red cells is greatly enhanced both during and after treatment with rabbit hemolytic factor whereas the entry of C(24)-sucrose, a small foreign molecule, is mediated only in the presence of hemolytic factor. Glycolysis neither protects against lysis nor enhances the activity of this system, and cardiac glycosides which are known inhibitors of active transport of ions also have no effect. It appears that lysis in this system is not brought about by increased active transport of ions into the cell but that the rabbit factor degrades or combines with some membrane component, altering permeability and resulting in increased diffusion, first of sodium and potassium ions and other small molecules, and finally of large molecules (hemoglobin) out of the cell.

Adenine Nucleotides↗
PubMed1959

An adenosinetriphosphate-activated hemolytic system. II. Utilization of adenosinetriphosphate in the reaction.

Failure to demonstrate ATP(1) utilization in an ATP-activated hemolytic system had been previously reported. In the present study ATP utilization is shown to be associated with the hemolytic reaction and also with the ATP-dependent inactivation of the hemolytic factor of the system by crude, washed, human red cell stroma. Using crude stroma, relatively large ATP utilization occurs and continues, but at a decreasing rate, after inactivation of the hemolytic factor is complete. With purified stroma there is very slight uptake of ATP by the stroma in the presence of hemolytic factor and Mg(++). This uptake can only be demonstrated by radioactive ATP. Both C(14)- and P(32)-labelled nucleotide were used for this purpose. In the presence of an excess of stroma the uptake seems to be dependent on the amount of hemolytic factor used. Evidence is given contraindicating the possibility that this uptake is non-specific.

Adenosine Triphosphate↗
PubMed1956

An adenosinetriphosphate-activated hemolytic system.

1. Hemolyzed rabbit cells contain a factor which lyses human erythrocytes in vitro when Mg(++) and certain nucleotides are supplied to the system. Of the nucleotides tested ATP is the most active, although no net loss of ATP or of labile phosphate seems to be associated with the hemolytic process. 2. The lytic factor appears to be a sulfhydryl enzyme which attacks the membrane of the human red cell, its hemolytic activity being inhibited by human stroma. 3. The system is activated by glutathione and is inhibited by heavy metals, oxidized glutathione, cysteine, ergothionine, and a number of metabolic inhibitors. Physostigmine has no effect. 4. Partial purification of the lytic factor has been achieved by fractional centrifugation.

Adenosine Triphosphate↗
PubMed1956

Efficiency of glutamyl peptide polymers as plasma volume extenders.

A series of polymers of polyglutamic acid have been tested as plasma volume expanders. The results indicate that those polymers prepared from backbones of 40,000 molecular weight or over and side chains of 3,000 molecular weight or over, will have plasma volume retention half-life of 15 hours or longer. Measurements of the oncotic efficiency of these polymers in vivo indicated a blood stream fluid retention of approximately 51 ml./gm. of polymer. Similar measurements of polymer-serum albumin solutions in vitro showed a retention of 52 ml./gm. of polymer. The clinical response to infusion of solutions of these polymers indicated no untoward pharmacological properties. Although the number of trials presented is too small for ultimate conclusion regarding either the physiological or clinical effects of these polymers, they do provide a strong indication of the desirability of further clinical testing of this polymer and a sound basis on which to plan the larger scale preparation of polymer. Both measures are currently under way.

Glutamates↗