Canadian clinical trial of antilymphocyte globulin in human cadaver renal transplantation.

A multicentre, randomized clinical trial of antilymphocyte globulin (ALG) was conducted among patients who had undergone cadaver kidney transplantation; follow-up was continued for a minimum of 1 year. Of the 179 patients 92 were given conventional treatment only, while 87 were given in addition ALG (from a standardized, highly immunosuppressive, common pool of equine ALG), 20 mg/kg-d intravenously for 10 days after transplantation. The ALG-treated group had better accumulated graft survival, fewer nephrectomies, better graft function, less than half the number of acute rejection episodes and less prednisone use. There was a beneficial drug (ALG)-related effect in both the graft and the host during the first 3 months after transplantation.     

Morphological and electrophysiological changes produced by electrical stimulation in cultured neuroblastoma cells.

Electric fields, which were equivalent to those generated by medical devices, were applied to cultured neuroblastoma cells (mouse and human) to test for morphological damage and to establish damage thresholds. Each of two methods of applying fields permitted flow of electrical current and minimized exposure of cells to electrode-breakdown products. One method consisted of a pair of parallel wires in a Petri dish by which current was delivered within a fixed volume of flowing tissue-culture media. With the other method, the cells were held in a confined geometrical chamber and current was applied via agar bridges. Under a given set of stimulation parameters, damage was found to be variable from cell to cell. By changing the strength of the electric field (frequency and duration of stimulation held constant), thresholds of several V/cm were found above which cell damage could be reliably produced. Depending on the intensity of the field, damage took the form of cell lysis or damage to neurites. Intracellular recordings from the mouse neuroblastoma cells revealed a correlation between a decline in resting transmembrane potential and stimulus intensity. Human neuroblastoma cells were less susceptible to damage than were the mouse neuroblastoma cells, given the same strength of applied electric fields.     

Yeast 5S rRNA binding to ribosomal protein L1a alters the fluorescence of tryptophan residues lying outside the binding site.

The yeast ribosomal protein L1a contains two tryptophan residues located at positions 95 and 183. Spectrofluorometric analysis showed that the average tryptophan environment is moderately polar. Quenching studies of the yeast 5S rRNA-L1a protein complex (RNP) with acrylamide and iodide revealed tryptophan heterogeneity. The two tryptophan residues are located in the non-RNA-binding region of the L1a molecule. However, dissociation of the yeast 5S rRNA-L1a protein RNP complex to its components resulted in a decline of tryptophan fluorescence. The observation implied that the environment of the tryptophan-containing L1a regions which were not known to be involved in RNA binding was influenced by association with the 5S rRNA molecule.     

A study of the apolar interaction of the enzyme rhodanese with octyl substituted agarose gel

The accessibilities of sites on the surface of the enzyme rhodanese for binding to macromolecular apolarity have been measured for the two forms of the enzyme related to obligatory catalytic intermediates: the free enzyme, E and the sulfur substituted enzyme, ES. This study was done using a micromethod developed for this purpose which allows facile assessment of the apolar binding of proteins to commercially available beads of cross-linked agarose on which hydrophobic groups have been immobilized. The results indicate that the enzyme rhodanese can bind to macromolecular apolarity and that there is considerably more binding of the E form than the ES form. The fact that the binding is relatively slow implicates a protein conformational change in the rate limiting binding step. In fact, there is a large increase in the binding when the temperature is raised from 23° to 40° which correlates with previous results showing a conformational change in rhodanese over the same temperature range. These results in comparison with other solution studies and with x-ray studies are consistent with a model for rhodanese which has an apolar active site and a mechanism for catalysis that includes a conformational change.