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R E Whatley

Publications and source records attributed to R E Whatley.

23 records · Page 2Linked to original sources
PubMedDate not supplied

Endothelial cells reestablish functional integrity after reversible permeabilization.

Permeabilization is an important tool in cell biology that allows manipulation of intracellular mechanisms by introduction of probes and regulatory molecules into the cell cytoplasm. We found that incubation of endothelial cells (ECs) with glass beads resulted in nonspecific permeabilization of human and bovine ECs without removal of the cells from monolayer culture. This poration of the plasma membrane allowed the introduction of macromolecules (dextrans less than or equal to 152 kd and immunoglobulins) as well as small, charged molecules (Lucifer Yellow). We found that nonspecific permeabilization of the EC was transient and defined the conditions under which integrity of the plasma membrane was reestablished. This process was dependent on time, temperature, and the presence of extracellular calcium. We also demonstrated that permeabilized ECs regain functional characteristics. This was defined by a number of criteria, including the ability to rapidly reestablish confluent monolayer morphology, to extrude Lucifer Yellow, to adhere and spread after passage, and to synthesize biologically active molecules after stimulation with a receptor-mediated agonist. Thus, transiently porated ECs loaded with appropriate probes can be used in studies of regulatory mechanisms while remaining in monolayer culture, a condition in which many phenotypic features are similar to in situ endothelium. Furthermore, the porated EC may be a useful model for defining the mechanisms that influence the repair of endothelial plasma membrane injury.

Acid-Base Equilibrium↗
PubMedDate not supplied

Endothelium from diverse vascular sources synthesizes platelet-activating factor.

Stimulation of cultured bovine endothelial cells from aorta, pulmonary artery, coronary artery, and vena cava with calcium ionophore A23187, adenosine triphosphate (ATP), bradykinin, and angiotensin II resulted in production of platelet-activating factor (PAF), 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine. In pulmonary artery endothelial cells, maximal accumulation occurred within 20 minutes, and the PAF remained cell-associated. This response was concentration-dependent with a maximal effect at 10(-8)M bradykinin and 10(-6)M angiotensin II. Stimulation of in situ endothelial cells on isolated strips of bovine pulmonary artery with calcium ionophore, ATP, and bradykinin also resulted in production of PAF. In cultured pulmonary artery endothelial cells, PAF appeared only in response to the same agonists that caused prostacyclin (PGI2) release. These findings are similar to earlier studies with human umbilical vein endothelial cells and suggest that the production of PAF and the arachidonate metabolite PGI2 are tightly linked in these vessels. Aortic endothelial cells, both in culture and on isolated strips of aorta, also produced PAF in response to bradykinin in a time-and concentration-dependent fashion. Cultured endothelial cells from coronary vessels and the inferior vena cava accumulated PAF when appropriately stimulated as well. The finding that both cultured endothelial cells and in situ, ex vivo endothelium from diverse vascular sites produce PAF when appropriately stimulated suggests that this is a generalized response of endothelial cells. Because PAF has potent vasoactive, pro-aggregatory, and pro-inflammatory effects, the results from these experiments suggest that the local accumulation of this lipid may be important in vascular injury and inflammation.

Adenosine Triphosphate↗