MS

thesisComparative chemotaxis studies of adult and newborn polymerphonuclear leukocytes (PMNs) were performed by a technique which adapted the micro-pore filter method to a multiwall chamber. Cord blood neutrophils responded to the chemoattractant FMLP with 60% of adult PMN activity. In order to investigate the defect of neonatal PMN chemotaxis as a calcium-associated phenomenon, PMNs wre suspended in a calcium-deprived buffer and in the presence of the calcium channel blocker, verapamil, before being assayed for migration. Adult neutrophils responded to both calcium manipulations with reduced chemotaxis as expected-19% inhibition in calcium-deprived media (p<0.05), and 32% reduction (p<0.001) with 10[-4] M verapamil, Neonatal PMNs, however, increased chemotactic activity in the absence of extracellular calcium-26% (p<0.05) and to a greater extent in the presence of 10[-4] M verapamil (p