Direct measurement of energetic electrons coupling to an imploding low-adiabat inertial confinement fusion capsule.

We have imaged hard x-ray (>100 keV) bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. We measure 570 J in electrons with E>100 keV impinging on the fusion capsule under ignition drive conditions. This translates into an acceptable increase in the adiabat α, defined as the ratio of total deuterium-tritium fuel pressure to Fermi pressure, of 3.5%. The hard x-ray observables are consistent with detailed radiative-hydrodynamics simulations, including the sourcing and transport of these high energy electrons.

Trisomic pregnancy and elevated FSH: implications for the oocyte pool hypothesis.

BACKGROUND: Some studies, but not all, support the hypothesis that trisomy frequency is related to the size of the oocyte pool, with the risk increased for women with fewer oocytes (older ovarian age). We tested this hypothesis by comparing hormonal indicators of ovarian age among women who had trisomic pregnancy losses with indicators among women with non-trisomic losses or chromosomally normal births. The three primary indicators of advanced ovarian age were low level of anti-Müllerian hormone (AMH), high level of follicle-stimulating hormone (FSH) and low level of inhibin B. METHODS: The analysis drew on data from two hospital-based case-control studies. Data were analyzed separately and the evidence from the two sites was combined. We compared 159 women with trisomic pregnancy losses to three comparison groups: 60 women with other chromosomally abnormal losses, 79 women with chromosomally normal losses and 344 women with live births (LBs) age-matched to women with losses. We analyzed the hormone measures as continuous and as categorical variables. All analyses adjust for age in single years, day of blood draw, interval in storage and site. RESULTS: AMH and inhibin B did not differ between women with trisomic losses and any of the three comparison groups. Mean ln(FSH) was 0.137 units (95% confidence interval (CI): 0.055, 0.219) higher for trisomy cases compared with LB controls; it was also higher, though not significantly so, for trisomy cases compared with women with other chromosomally abnormal losses or chromosomally normal losses. The adjusted odds ratio in relation to high FSH (≥ 10 mIU/ml) was significantly increased for trisomy cases versus LB controls (adjusted odds ratio (OR): 3.8, 95% CI: 1.6, 8.9). CONCLUSIONS: The association of trisomy with elevated FSH is compatible with the oocyte pool hypothesis, whereas the absence of an association with AMH is not. Alternative interpretations are considered, including the possibility that elevated FSH may disrupt meiotic processes or allow recruitment of abnormal follicles.

The Yugoslavia Prospective Study of environmental lead exposure.

The Yugoslavia Prospective Study of environmental lead exposure has studied the associations between exposure to lead and pregnancy outcomes; childhood neuropsychological, behavioral, and physical development; and hematologic, renal, and cardiovascular function. The cohort comprises 577 children born to women recruited at midpregnancy in two towns in Kosovo, Yugoslavia; one town is the site of a lead smelter, refinery, and battery plant and the other is 25 miles away and relatively unexposed. A sample of these children has been followed at 6-month intervals through 7.5 years of age. Blood lead concentrations ranged from 1 to 70 microg/dl. Exposure to lead was not associated with adverse pregnancy outcomes. Exposure was associated with modest decrements in intelligence, small increases in blood pressure, higher risks of proteinuria, small increases in behavior problems, and perturbed hematopoiesis. Only at low level exposures (i.e., <16 microg/dl) were small associations with decreased height found. We discuss methodological problems that may hinder causal interpretation of these data, namely, use of blood lead concentration as an exposure measure, confounding, and town-specific associations. We conclude that while reported associations are small, collectively they lend support to the notion that lead is a toxicant with numerous adverse health effects.

Prenatal cocaine exposure and school-age intelligence.

Assessments of the possible consequences of prenatal exposure to cocaine have been limited by lack of control for socio-demographic confounders and lack of follow-up into the school years. We evaluated intelligence at ages 6-9 years in 88 children from a cohort of 280 born between September 1, 1985 and August 31, 1986 and identified at birth as cocaine-exposed, and in a group of unexposed (n = 96) births of comparable gender and birthweight. IQ scores did not differ between children with and without prenatal exposure to cocaine (mean 82.9 vs. 82.4, difference = 0.5 points, 95% CI-3.1, 4.1); results were unchanged with adjustment for child height, head circumference and prior residence in a shelter or on the street, and for caregiver IQ and home environment (mean difference = 2.2 points, 95% CI-1.5, 5.8).

Lead exposure and intelligence in 7-year-old children: the Yugoslavia Prospective Study.

For a prospective study of lead exposure and early development, we recruited pregnant women from a lead smelter town and from an unexposed town in Yugoslavia and followed their children through 7 years of age. In this paper we consider associations between lifetime lead exposure, estimated by the area under the blood lead (BPb) versus time curve (AUC7), and intelligence, with particular concern for identifying lead's behavioral signature. The Wechsler Intelligence Scales for Children-Version III (WISC-III) was administered to 309 7-year-old children, 261 of whom had complete data on intelligence, blood lead, and relevant sociodemographic covariates (i.e., Home Observation for the Measurement of the Environment (HOME), birth weight, gender, sibship size, and maternal age, ethnicity, intelligence, and education). These showed anticipated associations with 7-year intelligence, explaining 41-4% of the variance in Full Scale, Performance, and Verbal IQ. Before covariate adjustment, AUC7 was unrelated to intelligence; after adjustment, AUC7 explained a significant 2.8%-4.2% of the variance in IQ. After adjustment, a change in lifetime BPb from 10 to 30 micro/dl related to an estimated decrease of 4.3 Full Scale IQ points; estimated decreases for Verbal and Performance IQ were 3.4 and 4.5 points, respectively. AUC7 was significantly and negatively related to three WISC-III factor scores: Freedom from Distractibility, Perceptual Organization, and Verbal Comprehension; the association with Perceptual Organization was the strongest. Consistent with previous studies, the IQ/lead association is small relative to more powerful social factors. Findings offer support for lead's behavioral signature; perceptual-motor skills are significantly more sensitive to lead exposure than are the language-related aspects of intelligence.

Blood lead and blood pressure in young children.

We examined associations between blood lead concentration (BPb) and blood pressure in 282 children age 5.5 years, residing in an exposed or unexposed town in Kosovo, Yugoslavia. Mean BPb in the exposed town was 37.3 micrograms per dl (standard deviation = 12.0 micrograms per dl) and in the unexposed town was 8.7 micrograms per dl (standard deviation = 2.8 micrograms per dl). After adjustment, a 10 micrograms per dl increase in BPb was associated with a 0.5 (95% CL = -0.2, 1.3) mmHg increase in systolic and a 0.4 (95%, CL = -0.1, 0.9) mmHg increase in diastolic blood pressure. These associations, although compatible with no relation, are similar to those observed in adults; and the data are most consistent with a small association between BPb and blood pressure.

Placental cadmium and birthweight in women living near a lead smelter.

It has been suggested that the accumulation of tobacco-derived cadmium (Cd) in the placenta is responsible for the adverse effect of cigarette smoking on infant birthweight. We chose to test this hypothesis; therefore, we studied a population of nonsmoking pregnant women who were exposed to low levels of smelter-derived Cd and a group of nonexposed women. A higher mean placental Cd concentration (p less than .0007) was found in the exposed women (n = 106), compared with those who were not exposed (n = 55); the observed Cd concentrations were comparable to concentrations reported previously for smoking and nonsmoking women, respectively. Least squares multiple regression (controlling for potentially confounding variables) revealed no association between placental Cd and birthweight. It was, therefore, concluded that the effect of smoking on birthweight was not mediated through Cd.

A prospective study of birthweight and length of gestation in a population surrounding a lead smelter in Kosovo, Yugoslavia.

This paper tests the hypothesis that exposure to lead during pregnancy is associated with reduced intrauterine growth and an increase in preterm delivery. The sample comprises women, recruited at mid-pregnancy, residing in Titova Mitrovica, a lead smelter town, or in Pristina, a non-exposed town 25 miles away. Both towns are in the province of Kosovo, Yugoslavia. Mean blood lead concentrations (BPb's) at mid-pregnancy were 0.92 mumol/L (+/- 0.38, N = 401) in the exposed town and 0.27 mumol/L (+/- 0.09, N = 506) in the comparison town. No differences were found between towns for either birthweight or length of gestation. Mean birthweight was 3308 (+/- 566) grams in Titova Mitrovica and 3361 (+/- 525) grams in Pristina. Mean length of gestation was 274 (+/- 18.8) days in Titova Mitrovica and 275 (+/- 15.6) days in Pristina. After adjustment for the effects of potential confounders, no significant relationships were found between maternal BPb measured at mid-pregnancy, at delivery or in the umbilical cord and either birthweight, length of gestation, or preterm delivery (less than 37 weeks). We conclude that exposure to environmental lead does not impair fetal growth or influence length of gestation.

Past pregnancy outcomes among women living in the vicinity of a lead smelter in Kosovo, Yugoslavia.

This analysis compares the rates of spontaneous abortion among women living in the vicinity of a lead smelter with those of women living in a town where blood lead levels were low. Data derive from the obstetric histories of both groups of women obtained while seeking prenatal care for a later pregnancy. A total of 639 women (304 exposed, 335 unexposed) had at least one previous pregnancy and lived at the same address since their first pregnancy. The geometric mean blood lead concentrations in the sample at the time of the interviews were 0.77 mumol/L in the exposed town and 0.25 mumol/L in the unexposed town. The rates of spontaneous abortions in first pregnancies were similar, with 16.4 percent of women in the exposed town and 14.0 percent in the unexposed town reporting loss. The adjusted odds ratio relating town of residence to spontaneous abortion was 1.1 (95% CI = 0.9, 1.4). This analysis represents the first systematic attempt to seek an association between environmental lead exposure and spontaneous abortion. As such, the failure to find a positive association strongly suggests that at the levels of exposure represented in our sample, such an association does not exist.

Evidence for a novel FMRFamide-related heptapeptide in the pulmonate snail Siphonaria pectinata.

Extracts of whole false limpets (Siphonaria pectinata) were analysed to determine their complement of FMRFamide-related peptides. As in other pulmonates, FMRFamide itself was found to account for only a portion of the immunoreactivity; the largest immunoreactive peptide peak eluted during HPLC under acidic conditions at the same position as a peak also found in other pulmonates. This major peak was resolved into two components by HPLC at neutral pH, and one component was identified as the heptapeptide amide, GDPFLRFamide, previously described from Lymnaea. The amino acid composition of the second component indicates that it is also a heptapeptide, but that it has two Asx (aspartic acid or asparaginyl) residues instead of the one found in the previously identified pulmonate heptapeptides.

Maternal occupation: effects on spontaneous abortions and malformations.

The epidemiology of spontaneous abortion is described and the literature relating selected occupations to spontaneous abortion and to malformations is reviewed. A study on the effects of anesthetic gases on pregnancy outcome is presented to demonstrate approaches to research.