Effects of gravity and the presence of erythrocytes on platelet and granulocyte adhesion in stagnant blood 1

Abstract

Effects of gravity in presence and absence of red blood cells, on adhesion of platelets to polyvinylchloride (pvc) slides, and of granulocytes to gamma globulin preabsorbed onto pvc, were studied by placing whole heparinized human blood or its red cell poor supernatant between 2 slides, and allowing this sandwich to reside in 1 position followed by the inverted one for various periods. Counts of adhering elements indicated that a) settling red cells drastically interfered with platelet and granulocyte adhesion to the surfaces facing up, but enhanced their adherence to surfaces facing down; b) in absence of red cells, granulocytes adhered in great numbers to the globulin surfaces and platelets to the “blank” surfaces facing up during the first 5 min of the experiment, and few adhered to the surfaces that had faced down; c) upon inversion, granulocytes would still refuse to adhere to the surfaces that had initially faced down, while platelet adhesion increased during the subsequent 30 min; the nonadhering granulocytes would still be able to adhere if transferred to a new globulin-coated pvc surface facing up, and unused supernatant would still deposit granulocytes onto the used globulin-coated pvc surfaces if facing up. Experiments to be performed at near 0 gravity are suggested.