778 Biologic events resulting from contamination of the abdomen or injury to the mesothelial cells include release of catecholamines, histamine, and serotonin from peritoneal mast cells; vasodilation and hyperemia; an increase in peritoneal vascular permeability; secretion of protein-rich fluid into the peritoneum; transformation of mesothelial cells into macrophages; and influx of PMN cells, humoral opsonins, natural antibodies, and serum complement into the peritoneal cavity.