ristocetin and Pre-Eclampsia

We determined in normal nonpregnant (group 1) women, normal pregnant (group 2) women, and patients with preeclampsia (group 3) the serum inhibition of platelet-activating factor activity, the presence of detectable amounts of platelet-activating factor in the blood, and platelet responsiveness in vitro to platelet-activating factor, and to other agonists (adenosine diphosphate, collagen, and ristocetin), and prostacyclin (prostaglandin I2). In patients with preeclampsia (group 3) the serum inhibition of platelet-activating factor activity was significantly lower than that in groups 1 and 2. However, no detectable amounts of platelet-activating factor were observed. The mean values of platelet aggregation induced by platelet-activating factor, adenosine diphosphate, collagen and ristocetin, and the prostaglandin I2-inhibitory concentration of 50% which is inversely correlated with platelet sensitivity to prostaglandin I2, were not significantly different between groups 2 and 3. It is suggested that in preeclampsia the defect in serum inhibitory potential of platelet-activating factor--induced platelet aggregation may contribute to the disturbance in the homeostatic balance between proaggregant and antiaggregant substances.

Topics: Adenosine Diphosphate; Adult; Chromatography, Thin Layer; Collagen; Female; Humans; Platelet Activating Factor; Platelet Aggregation; Pre-Eclampsia; Pregnancy; Ristocetin

We determined in normal nonpregnant (group I) and normal pregnant (group II) women and in patients with preeclampsia (group III): (1) immunoglobulins and complement C3b associated with polymorphonuclear leukocytes and platelet surfaces in an attempt to evaluate the interaction in vivo of immune complexes with the membranes of these cells; (2) the occurrence of circulating immune complexes; (3) the serum levels of immunoglobulins, C3, and C4; and (4) the plasma levels of complement C3d. In patients with preeclampsia (group III), the percentages of polymorphonuclear leukocytes and platelets positive for membrane-bound IgG, IgM, IgA, and C3 were significantly higher than the percentages in groups I and II. In group III, there also was a significant increase in circulating immune complexes, as compared to groups I and II. However, circulating immune complexes were also present in significant amounts in normal pregnancy (group II). The plasma levels of complement C3d were markedly increased in the most severe cases of preeclampsia.

Topics: Adult; Antigen-Antibody Complex; Blood Platelets; Complement Activation; Complement C3; Complement C3b; Complement C3d; Complement C4; Female; Humans; Immunoenzyme Techniques; Immunoglobulins; Latex Fixation Tests; Neutrophils; Pre-Eclampsia; Pregnancy; Ristocetin