Faculty Bibliography

Three scorpion venoms caused a transitory decrease in the rate of fluid secretion and increases in the concentration, in pancreatic juice, of total protein and individual enzymes. Protein and enzyme elevations 4-7 fold over the basal levels were produced by the venom of Tityus bahiensis and 6-7 fold by venoms from Tityus serrulatus and Buthus quinquestriatus. Although these increases were smaller than those stimulated by the C-terminal octapeptide of cholecystokin (OP-CCK; 8-9 fold), the secretory responses were of longer duration, so that the total output of protein caused by each of the three venoms was significantly greater than that observed with OP-CCK. Although electron microscopy revealed evidence of widespread degeneration of acinar cells at 1 hr and more extensive damage at 2 hr following injection of scorpion venom, no free protease was detected in pancreatic secretion collected during this period. The scorpion venoms also caused hypersecretion of viscid saliva. In contrast, rattlesnake venom, had no detectable effect on salivation, pancreatic secretion or morphology of the pancreas.

We studied the capacities of naked and protein-coated monosodium urate (MSU) crystals to stimulate superoxide anion (O(2)) release by human polymorphonuclear leukocytes (PMN). Uncoated MSU estimated significant O(2) production by cytochalasin B-treated PMN. Precoating MSU with IgG caused an increase in mean O(2) production, whereas precoating heated MSU with serum or plasma inhibited O(2) release. Unheated MSU crystals, which activate complement to a greater extent than heated crystals, also provoked O(2) generation, an effect again abrogated by precoating with serum but not with plasma. Coincubation of unheated MSU and plasma resulted in an enhancement of O(2) generation. The results of these experiments support the hypothesis that adsorbed proteins modulate the phlogistic potential of MSU and that the surface activation of humoral mediators contributes to the local inflammatory response

Human polymorphonuclear leukocytes exposed to phagocytic stimuli undergo a series of cellular reactions designed to eliminate foreign invaders such as bacteria, viruses, or fungi. The responses of human granulocytes to the stimuli of phagocytosis are initiated at the cell surface and proceed in the following sequence: a. ligand binding to surface receptors; b. membrane hyperpolarization; c. O2- generation by a surface oxidase and 1O2 metabolism; d. generation of thromboxanes and prostaglandins; e. lysosomal enzyme secretion. These events, known as 'stimulus-secretion coupling', result in the secretion of toxic substances which, though intended to end up in the phagocytic vacuole, may escape to the extracellular space where they initiate inflammation