Comments on the role of H2S in the chemistry of Earth's early atmosphere and in prebiotic synthesis.

: Free energy calculations and experimental measurements have been used to show that H2S/CO2 mixtures outgassing from a prebiotic Earth's crust would have produced a reducing gas mixture containing CO, H2, H2O, and Sx as principal components. Due to rapid recombination of H2, CO, and Sx to H2S and CO2 on cooling from a high temperature to ambient conditions, reducing components would have been retained only if efficient quenching of the reduced gas mixture had been possible. Consequently, subsea vents or vents with efficient infusion of water would have been ideal sites for retention of reduced species and for prebiotic organic synthesis. It is suggested that C/H/O/S ratios are important factors in controlling the degree of prebiotic organic synthesis and, hence, the emergence of life, since if oxygen is abundant, CO2 and SO2 would have been dominant species.

Binding of a novel radioiodinated thromboxane A2/prostaglandin H2 antagonist to guinea pig lung membranes.

The utilization of a novel radioiodinated TXA2/PGH2 receptor antagonist, ISAP (7-[(1R,2S,3S,5R)-6,6-dimethyl-3(4- iodobenzenesulfonylamino)-bicyclo[3.1.1]-hept-2-yl]-5(Z)-heptenoic acid) to characterize TXA2/PGH2 receptors from guinea pig lung parenchymal membranes in radioligand binding assays is described. [125I]ISAP binding was saturable, displaceable, and dependent upon protein concentration. The time course of binding yielded k1 = 2.12 x 10(8) M-1 min-1, k1 = 4.46 x 10(-3) min-1, Kd = k-1/k1 = 17.8 pM. Equilibrium binding studies indicated a single class of high affinity binding sites with a Kd of 52.7 +/- 1.9 pM and a Bmax of 92.7 +/- 7.2 fmoles/mg protein (n = 4). Binding was inhibited by a series of structurally diverse mimetics and antagonists with the rank order of potency IBOP greater than ONO11113 = SQ26655 greater than U46619 (mimetics) and (d)-S-145 greater than ISAP greater than (1)-S-145 greater than SQ29548 greater than BM13505 = I-PTA-OH (antagonists), with entantioselectivity of binding demonstrated by (d) and (1) S-145. Binding was also inhibited by prostanoids (PGD2, PGF2 alpha, and 9 alpha, 11 beta-PGF2) thought to act at the airway TXA2/PHH2 receptor, but not by histamine or carbachol, and only weakly by LTB4 and LTD4, consistent with specific binding to the lung TXA2/PGH2 receptor.

Alcohol and substance abuse among schizophrenic patients presenting to an emergency psychiatric service.

To obtain information regarding patterns of alcohol and substance use, portions of the Diagnostic Interview Schedule (DIS) were administered to 53 schizophrenic patients who presented to the crisis service of an emergency room in a major general hospital. The number of individuals in the sample qualifying for a lifetime diagnosis of an alcohol abuse-related disorder was quite high (47%), and there was a strong correlation between disorders of alcohol abuse and the use of other drugs. Other than alcohol, marijuana was the most frequently abused drug. Individuals who qualified for a diagnosis of an alcohol-related disorder were compared with those who did not on a variety of diagnostic and demographic variables. The authors conclude by suggesting that the high-risk rates of drug use-related disorders reported in this sample may be due to the preferential use of emergency services by schizophrenic patients with alcohol and drug abuse-related disorders.

Determinants of blood lead concentrations of pregnant women living in Port Pirie and surrounding areas.

In the context of a wider prospective investigation into the effects of cumulative exposure to lead, in utero and postnatally, on the outcome of pregnancy and growth and development in early childhood, 831 pregnant women who were living in Port Pirie, South Australia, the site of Australia's largest lead smelter, were recruited between May 1979 and May 1982, and the various factors that were likely to influence their blood lead concentration were examined. No significant difference in blood lead level was found among different stages of pregnancy. Higher concentrations of blood lead were measured in women who resided in areas of high soil lead content and in women who had resided in Port Pirie for three or more years. A low socioeconomic status, the use of water from the reticulated water supply rather than rainwater, an age of 21 years or less, a high body mass index, a low dietary intake of calcium, and cigarette smoking were all factors that were associated with a higher blood lead concentration. Lower blood lead concentrations were observed in women who took iron and folic acid to supplement their diet. Multiple regression analysis of average antenatal blood lead levels confirmed most of the univariate associations.

The Port Pirie cohort study: maternal blood lead and pregnancy outcome.

During a three-year period, 831 pregnant women in and around Port Pirie, South Australia--a lead smelter community with longstanding lead pollution--were enrolled in a cohort study to examine prospectively the relation between body lead burden and pregnancy outcome. Three-quarters of the enrolled women were residents of the Port Pirie municipality; the other women lived in adjacent towns and countryside. At 14-20 weeks' gestation, the Port Pirie resident women had a mean blood lead concentration of 10.6 micrograms/dl, while the mean in the other (non-Port Pirie) women was 7.6 micrograms/dl. Similar differences were observed in maternal blood samples taken at 30-36 weeks, at delivery, and from the umbilical cord. These blood lead measures, in conjunction with information collected on other risk factors, were then examined in relation to pregnancy outcome. Among 749 pregnancies followed to completion, pre-term delivery was statistically significantly associated, in a dose-response manner, with maternal blood lead concentration at delivery. Mothers of late fetal deaths (stillbirths) had blood lead concentrations at 14-20 weeks' gestation similar to those of all the other women but had lower concentrations at delivery than the other women. Outcomes of pregnancy for which no association with blood lead was detected were spontaneous abortion, low birthweight (for births at term), intrauterine growth retardation, premature rupture of the membranes, and congenital anomalies.