Nonmuscle Myosin IIA Regulates Platelet Contractile Forces Through Rho Kinase and Myosin Light-Chain Kinase.

Platelet contractile forces play a major role in clot retraction and help to hold hemostatic clots against the vessel wall. Platelet forces are produced by its cytoskeleton, which is composed of actin and nonmuscle myosin filaments. In this work, we studied the role of Rho kinase, myosin light-chain kinase, and myosin in the generation of contractile forces by using pharmacological inhibitors and arrays of flexible microposts to measure platelet forces.

Glycoprotein Ib-IX-V Complex Transmits Cytoskeletal Forces That Enhance Platelet Adhesion.

Platelets bind to exposed vascular matrix at a wound site through a highly specialized surface receptor, glycoprotein (GP) Ib-IX-V complex, which recognizes von Willebrand factor (VWF) in the matrix. GPIb-IX-V is a catch bond for it becomes more stable as force is applied to it. After attaching to the wound site, platelets generate cytoskeletal forces to compact and reinforce the hemostatic plug.

Mode of delivery in pregnancies complicated by preeclampsia with very low birth weight infants.

The aims of this study were to examine data from an institution at which the goal has been to pursue vaginal delivery in patients with a preterm gestation and preeclampsia and to test the hypothesis that labor does not increase the risk of poor outcome for the preterm infant of a mother with preeclampsia. An analysis of all singleton infants born live who weighed 1500 gm or less and who were born to mothers with preeclampsia or eclampsia from 1975 to 1990 was undertaken. The infants who were delivered by cesarean section without labor and with a reassuring fetal assessment were compared with the infants who went through labor.

Cost effects of surfactant therapy for neonatal respiratory distress syndrome.

Objective: To examine the cost effects of a single dose (5 ml/kg) of a protein-free synthetic surfactant (Exosurf) as therapy for neonatal respiratory distress syndrome, for both rescue and prophylactic therapy.

Research Design: Nonblinded, randomized clinical trials of both rescue and prophylactic therapy. Regression analyses were used to control for the independent effects of sex, multiple birth, delivery method, birth weight, and surfactant therapy.

Initial clinical trial of EXOSURF, a protein-free synthetic surfactant, for the prophylaxis and early treatment of hyaline membrane disease.

EXOSURF is a protein-free surfactant composed of 85% dipalmitoylphosphatidylcholine, 9% hexadecanol, and 6% tyloxapol by weight. A single dose of 5 mL of EXOSURF per kilogram body weight, which gave 67 mg of dipalmitoylphosphatidylcholine per kilogram body weight, or 5 mL/kg air was given intratracheally in each of two controlled trials: at birth to neonates 700 through 1350 g (the prophylactic trial, n = 74) or at 4 to 24 hours after birth to neonates greater than 650 g who had hyaline membrane disease severe enough to require mechanical ventilation (the rescue trial, n = 104). In both studies, time-averaged inspired oxygen concentrations and mean airway pressures during the 72 hours after entry decreased significantly (P less than .