Metals of the bottom muds in Belize City Harbor, Belize.

Seven bottom samples extending from the ocean up through Belize Harbor and City were acid leached (EPA method 200.7) and analyzed using inductively coupled plasma spectrometry to measure the bioavailability of Cd, Cr, Cu, Pb and Zn. Soil and environmental chemists would compare data to world averages of unpolluted soils, these samples were higher than this average by a factor of 10 for Cd, 4 for Cu, 2.7 for Zn and 2.6 for Pb. Geochemists argue that it's hard to find unpolluted soil so their comparison is with world average of ancient (pre-man) shales and the Belize samples were higher than this shale average by a factor of 30 for Cd, 3.7 for Pb, 2.2 for Cu and 1.7 for Zn. Ecologists would argue that the metal effect on the biota is the correct way to analyze the data by using the biological effects toxicity method, and this way the samples were above the lower limit by a factor of 5.1 for Cd, 2.9 for Cu and 1.6 for Pb. By all three lines of reasoning, it can be concluded that Cd, Cu, Pb and Zn, in that order, pose environmental problems. Since this site is located in the middle of Belize Barrier Reef, a highly sensitive environmental area that is also economically important to Belize, it poses a critical problem that needs to be addressed further.

Prevalence of asymptomatic hepatitis B infection in pregnant Mexican-American women.

Recent reports document high rates of asymptomatic hepatitis B virus infection in pregnant Hispanic women of Caribbean and Latin American origin, frequently in the absence of identifiable risk factors. We hypothesized that the prevalence of asymptomatic hepatitis B virus infection in Mexican-American women was much lower and that most belonged to established risk groups. Three thousand seven hundred eight-nine pregnant women, 77% of whom had Hispanic surnames, were screened for hepatitis B surface antigen upon admission in labor to Medical Center Hospital in San Antonio. Twelve women, six of whom had Hispanic surnames, were found to have asymptomatic hepatitis B infections. The prevalence of asymptomatic infections was 3.2 per 1000 (95% confidence interval 1.6-5.5) in the total population, 2.0 per 1000 (95% confidence interval 0.7-4.5) in those with Hispanic surnames, and 7.0 per 1000 (95% confidence interval 2.5-15.0) in those with non-Hispanic surnames. Risk factors, as defined by the Centers for Disease Control, were found in five (42%) of the positive patients overall and in only one (17%) of the positive patients with an Hispanic surname. We conclude that, although asymptomatic hepatitis B infection is uncommon in these pregnant Mexican-American women, the absence of identifiable risk factors in the majority of those infected suggests that routine screening in this population is justified.

Risk factors for preterm premature rupture of fetal membranes: a multicenter case-control study.

To assess the association between women with preterm premature rupture of membranes and 41 potential risk factors, we conducted a case-control study in six United States tertiary perinatal centers. The study involved completion of a comprehensive questionnaire for 341 women with preterm premature rupture of membranes in singleton pregnancies from 20 to 36 weeks' gestation and 253 control women matched for maternal age, gestational age, parity, clinic or private patient status, and previous vaginal or cesarean delivery. Univariate analysis revealed 11 variables associated with a significantly (p less than 0.05) increased risk of preterm premature rupture of membranes. After multiple logistic regression analysis, three variables remained in the model as independent risk factors: antepartum vaginal bleeding in more than one trimester (odds ratio 7.4; 95% confidence interval, 2.2, 25.6), current cigarette smoking (odds ratio, 2.1; 95% confidence interval, 1.4, 3.1), and previous preterm delivery (odds ratio, 2.5; 95% confidence interval, 1.4, 2.5). Cessation of cigarette smoking by pregnant women may reduce the risk of preterm premature rupture of membranes. Further study is necessary to determine the nature of the relationship between antepartum vaginal bleeding and preterm premature rupture of membranes.