Human endometrial nuclear estrogen receptors among Norplant implant users.

Twenty-four parous women were included in this study. Sixteen cases were using the Norplant implant contraceptive system for more than 6 months (Group A) while eight cases served as matched controls in the secretory phase (Group B). Norplant implant users belonged to one of two equal subgroups according to whether they experienced regular menstrual bleeding (Subgroup A1) or prolonged episodes of amenorrhoea (Subgroup A2). Endometrial samples were processed for nuclear oestrogen receptor assay and for evaluation of the receptor's binding affinity to oestrogen. The results showed marked reduction in endometrial nuclear oestrogen receptors in Norplant users compared with controls as the majority of users had undetectable receptor levels. This down-regulation effect was significantly more pronounced among women with prolonged episodes of amenorrhoea. The affinity section of the study revealed no significant differences between groups or subgroups probably due to the small number of subjects with detectable receptor concentrations for comparison. These data may help in the understanding of contraceptive mechanisms and menstrual associated problems, and in the development of therapeutic measures.     

Time-dependent inhibition and tetrahydrobiopterin depletion of endothelial nitric-oxide synthase caused by cigarettes.

Smoking causes a dysfunction in endothelial nitric-oxide synthase (eNOS), which is ameliorated, in part, by administration of tetrahydrobiopterin (BH(4)). The exact mechanism by which the nitric oxide deficit occurs is unknown. We have previously shown that aqueous extracts of chemicals in cigarettes (CE) cause the suicide inactivation of neuronal NO synthase (nNOS) by interacting at the substrate-binding site. In the current study, we have found that CE directly inactivates eNOS by a process that is not affected by the natural substrate l-arginine and is distinct from the mechanism of inactivation of nNOS. We discovered that CE causes a time-, concentration-, and NADPH-dependent inactivation of eNOS in an in vitro system containing the purified enzyme, indicating a metabolic component to the inactivation. The CE-treated eNOS but not nNOS was nearly fully reactivated upon incubation with excess BH(4), suggesting that BH(4) depletion is a potential mechanism of inactivation. Moreover, in the presence of CE, eNOS catalyzed the oxidation of BH(4) to dihydrobiopterin and biopterin by a process attenuated by high concentrations of superoxide dismutase but not catalase. We speculate that a redox active component in CE, perhaps a quinone compound, causes oxidative uncoupling of eNOS to form superoxide, which in turn oxidizes BH(4). The discovery of a direct inactivation of eNOS by a compound(s) present in tobacco provides a basis not only for further study of the mechanisms responsible for the biological effects of tobacco but also a search for a potentially novel inactivator of eNOS.     

A Comparative Study to Evaluate the Essential Work of Fracture to Measure the Fracture Toughness of Quasi-Brittle Material

In the present work, three different woven composite laminates were fabricated using the hand lay-up method. The woven reinforcement fibres were carbon fibres (CFRP), glass fibres (GFRP-W) and (GFRP-R) in combination with epoxy resin. Then, the central notch specimen tensile test (CNT) was used to measure the fracture toughness and the corresponding surface release energy (GIC). Then, the data were compared with the essential work of fracture (we) values based on the stored energy of the body to obtain a new standard fracture toughness test for composite laminates using relatively simple techniques. In addition to an extended finite element model, XFEM was implemented over a central notch specimen geometry to obtain a satisfactory validation of the essential work of fracture concepts. Therefore, the average values of (GIC) were measured with CNT specimens 25.15 kJ/m², 32.5 kJ/m² and 20.22 kJ/m² for CFRP, GFRP-W and GFRP-R, respectively. The data are very close as the percentage error for the surface release energy measured by the two methods was 0.83, 4.6 and 5.16 for carbon, glass and random fibre composite laminates, respectively. The data for the fracture toughness of XFEM are also very close. The percentage error is 4.6, 5.25 and 2.95 for carbon, glass and random fibre composite laminates, respectively. Therefore, the fundamental work of the fracture concept is highly recommended as a fracture toughness test for composite laminates or quasi-brittle Material.     

Drug-prescribing patterns during pregnancy in the tertiary care hospitals of Pakistan: a cross sectional study

Background

Low birth weight (LBW) is considered as a major multifaceted public health concern. Seventy-two percent of LBW infants are born in Asia. An estimation of 8% LBW infants has been reported for Eastern Mediterranean region including Iran. This study investigated contributory factors of LBW in singleton term births in Tehran, Iran. Tehran is a multicultural metropolitan area and a sample from the general population in Tehran could be regarded as a representative sample of urban population in Iran.

Methods

This was a retrospective study using data from 15 university maternity hospitals in Tehran, Iran. Data on all singleton term births in these hospitals were extracted from case records during a one calendar year. Study variables included: maternal age, maternal educational level, history of LBW deliveries, history of preterm labor, cigarette smoking during pregnancy, number of parities, chronic diseases and residential area (Tehran versus suburbs of Tehran). In order to examine the relationship between LBW and demographic and reproductive variables the adjusted logistic regression analysis was performed.

Results

In all, data for 3734 term pregnancies were extracted. The mean age of women was 25.7 (SD = 5.3) years and 5.2% of term births were LBW. In addition to association between LBW and maternal age, significant risk factors for LBW were: history of LBW deliveries [adjusted odds ratio (OR) = 2.53, 95% confidence interval (CI) = 1.06–6.03], smoking during pregnancy (OR = 4.64, 95% CI = 1.97–10.95) and chronic diseases (OR for hypertension = 3.70, 95% CI = 2.25–6.06, OR for others = 2.04, 95% CI = 1.09–3.83).

Conclusion

The findings indicate that in addition to maternal age, history of LBW deliveries; smoking during pregnancy and chronic diseases are significant determinants of LBW in this population. This is consistent with national and international findings indicating that maternal variables and risk behaviors during pregnancy play important roles on LBW.     

Acceptance of preimplantation genetic diagnosis for beta-thalassemia in Lebanese women with previously affected children

OBJECTIVE: The aim of the study was to assess the rate of acceptance of preimplantation genetic diagnosis (PGD) as an alternative to prenatal diagnosis in Lebanese women with previously affected children with homozygous beta-thalassemia. METHODS: Women with a previously affected child attending a nongovernmentally funded thalassemia care center between 1 June 2005 and 31 May 2007 were offered a genetic counseling session. This was followed by administering a questionnaire through direct interview. RESULTS: All 97 women approached accepted to participate in the study (100% response rate). Sixty eight per cent of women considered PGD a better alternative to prenatal diagnosis. The most important perceived advantage of PGD was the avoidance of termination of an affected pregnancy. CONCLUSIONS: PGD is an acceptable alternative to conventional prenatal diagnosis in women at risk of conceiving a child affected with beta-thalassemia. This is particularly true in countries of the Middle-East where therapeutic abortions for fetal indications are prohibited by the law and religion. Copyright (c) 2008 John Wiley & Sons, Ltd.     

Pregnancy outcome in patients with previous uterine rupture

BACKGROUND: To review the outcome of subsequent pregnancies in conservatively managed cases of uterine rupture. METHODS: Charts of patients with full thickness uterine rupture in the past 25 years were reviewed and information on subsequent pregnancies was extracted from maternal and neonatal charts. RESULTS: Thirty-seven patients with uterine rupture were identified; the uterus was scarred in 62.2%. Ruptures were repaired in 26 (70.3%). Twelve patients subsequently conceived (24 pregnancies), with recurrence in 8/24 (33.3%) pregnancies or 5/12 (41.7%) patients. Patients with recurrence had a shorter median interval from previous rupture (2 versus 5 years), a higher incidence of previous longitudinal ruptures (60.0% versus 0.0%), and the median gestational age at the preceding rupture was lower without reaching statistical significance (34 versus 38 weeks; p = 0.209). CONCLUSIONS: Longitudinal ruptures and short intervals between rupture and subsequent pregnancy predispose to recurrence of uterine rupture.     

Marked hypocalcemia after tocolytic magnesium sulphate therapy

Symptomatic hypocalcemia has been reported infrequently in association with magnesium sulfate (MgSO (4)) tocolytic therapy. We report a 38-year-old woman who presented in preterm labor at 24 3/7 weeks. Twenty hours after starting MgSO (4), she developed chest pain. Studies revealed therapeutic serum Mg level, total serum calcium (Ca) = 5.5 mg/dL, 24-hour urine Ca = 763.9 mg, and low serum uric acid and phosphate levels. All studies corrected day 1 postpartum; urine Ca level corrected on day 2. Even short courses of MgSO (4) can result in severe hypocalcemia, raising the question of whether Ca levels should be routinely monitored.