321 research outputs found

    Metformin use in pregnancy: promises and uncertainties

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    Metformin has been prescribed in pregnancy for over 40 years; for much of this time, use has been limited both in numbers and geographically, and the evidence base has been confined to observational studies. In early years, perceived safety concerns and lack of availability of the drug in many countries acted as a barrier to use. More recently, RCTs have begun to examine the role of metformin in pregnancy in much-needed detail. However, this evidence base has been interpreted differently in different countries, leading to very wide variation in its current application in pregnancy. In this short review, we will discuss the history of metformin in pregnancy and highlight some of the key clinical trials. We will then consider some of the remaining controversies associated with metformin use in pregnancy, most important of these being the potential for long-term ‘programming’ effects on the fetus as a result of metformin being able to cross the placenta. We will also consider clinical situations where metformin might be avoided. Finally, we will discuss some future directions for this drug as it reaches its sixtieth anniversary

    Identification of a new binding motif for the paired domain of Pax-3 and unusual characteristics of spacing of bipartite recognition elements on binding and transcription activation

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    Pax-3, a transcription factor that is required for development of the embryonic neural tube, neural crest, and somitic derivatives, contains two DNA-binding domains, a paired domain, and a paired-type homeodomain. Although Pax-3 binds to sequences related to the e5 element of the Drosophila even-skipped gene, the sequence requirements of an optimal Pax-3 response element have not been well characterized. Using both DNA-binding domains and a pool of random oligonucleotides, we identified a new paired box consensus motif, “GTTAT,” which was located 1, 4, 5, 8, or 13 base pairs downstream of the homeobox binding motif, “ATTA.” Binding analysis of these sequences demonstrated that the distance between recognition elements for the homeodomain and the paired domain affects affinity. Specifically, spacing elements 1 or 13 base pairs apart from each other conferred low affinity Pax-3 binding, whereas intermediate spacing (5 or 8 base pairs) conferred high affinity binding. Contrary to previous reports, oligonucleotides deleted for either the ATTA or the GTTAT could also be bound by Pax-3, although both sites were necessary for maximal affinity. Finally, transient transfections demonstrated that Pax-3 trans-activation correlated with binding affinity. Because the Pax-3-responsive genes identified to date contain almost exclusively low affinity binding sequences, our analysis indicates that they may be responsive to Pax-3 only when cellular levels are high

    Lipid-soluble Vitamins A, D, and E in HIV-Infected Pregnant women in Tanzania.

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    There is limited published research examining lipid-soluble vitamins in human immunodeficiency virus (HIV)-infected pregnant women, particularly in resource-limited settings. This is an observational analysis of 1078 HIV-infected pregnant women enrolled in a trial of vitamin supplementation in Tanzania. Baseline data on sociodemographic and anthropometric characteristics, clinical signs and symptoms, and laboratory parameters were used to identify correlates of low plasma vitamin A (<0.7 micromol/l), vitamin D (<80 nmol/l) and vitamin E (<9.7 micromol/l) status. Binomial regression was used to estimate risk ratios and 95% confidence intervals. Approximately 35, 39 and 51% of the women had low levels of vitamins A, D and E, respectively. Severe anemia (hemoglobin <85 g/l; P<0.01), plasma vitamin E (P=0.02), selenium (P=0.01) and vitamin D (P=0.02) concentrations were significant correlates of low vitamin A status in multivariate models. Erythrocyte Sedimentation Rate (ESR) was independently related to low vitamin A status in a nonlinear manner (P=0.01). The correlates of low vitamin D status were CD8 cell count (P=0.01), high ESR (ESR >81 mm/h; P<0.01), gestational age at enrollment (nonlinear; P=0.03) and plasma vitamins A (P=0.02) and E (P=0.01). For low vitamin E status, the correlates were money spent on food per household per day (P<0.01), plasma vitamin A concentration (nonlinear; P<0.01) and a gestational age <16 weeks at enrollment (P<0.01). Low concentrations of lipid-soluble vitamins are widely prevalent among HIV-infected women in Tanzania and are correlated with other nutritional insufficiencies. Identifying HIV-infected persons at greater risk of poor nutritional status and infections may help inform design and implementation of appropriate interventions

    Noble gases in twenty Yamato H-chondrites: Comparison with Allan Hills chondrites and modern falls

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    Concentration and isotopic composition of noble gases have been measured in 20 H-chrondrites found on the Yamato Mountains ice fields in Antarctica. The distribution of exposure ages as well as of radiogenic He-4 contents is similar to that of H-chrondrites collected at the Allan Hills site. Furthermore, a comparison of the noble gas record of Antarctic H-chrondrites and finds or falls from non-Antarctic areas gives no support to the suggestion that Antarctic H-chrondrites and modern falls derive from differing interplanetary meteorite populations

    Pax3 Stimulates p53 Ubiquitination and Degradation Independent of Transcription

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    Background: Pax3 is a developmental transcription factor that is required for neural tube and neural crest development. We previously showed that inactivating the p53 tumor suppressor protein prevents neural tube and cardiac neural crest defects in Pax3-mutant mouse embryos. This demonstrates that Pax3 regulates these processes by blocking p53 function. Here we investigated the mechanism by which Pax3 blocks p53 function. Methodology/Principal Findings We employed murine embryonic stem cell (ESC)-derived neuronal precursors as a cell culture model of embryonic neuroepithelium or neural crest. Pax3 reduced p53 protein stability, but had no effect on p53 mRNA levels or the rate of p53 synthesis. Full length Pax3 as well as fragments that contained either the DNA-binding paired box or the homeodomain, expressed as GST or FLAG fusion proteins, physically associated with p53 and Mdm2 both in vitro and in vivo. In contrast, Splotch Pax3, which causes neural tube and neural crest defects in homozygous embryos, bound weakly, or not at all, to p53 or Mdm2. The paired domain and homeodomain each stimulated Mdm2-mediated ubiquitination of p53 and p53 degradation in the absence of the Pax3 transcription regulatory domains, whereas Splotch Pax3 did not stimulate p53 ubiquitination or degradation. Conclusions/Significance: Pax3 inactivates p53 function by stimulating its ubiquitination and degradation. This process utilizes the Pax3 paired domain and homeodomain but is independent of DNA-binding and transcription regulation. Because inactivating p53 is the only required Pax3 function during neural tube closure and cardiac neural crest development, and inactivating p53 does not require Pax3-dependent transcription regulation, this indicates that Pax3 is not required to function as a transcription factor during neural tube closure and cardiac neural crest development. These findings further suggest novel explanations for PAX3 functions in human diseases, such as in neural crest-derived cancers and Waardenburg syndrome types 1 and 3

    Diabetic fetopathy associated with bilateral adrenal hyperplasia and ambiguous genitalia: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Many fetal malformations can occur because of maternal diabetes. However, ambiguous genital organs have never been reported as an associated finding in the literature. This is the first report of associated ambiguous genital organ and bilateral adrenal hyperplasia in a case of diabetic fetopathy.</p> <p>Case presentation</p> <p>A 19-year-old Thai primigravida with familial history of diabetes mellitus (DM) was diagnosed as having gestational DM type 2, based on 100 g oral glucose tolerance test, and was poorly controlled with insulin injections. Delayed targeted ultrasonography at 28 weeks gestation revealed multiple fetal anomalies. The woman underwent low transverse cesarean section at 30 weeks gestation due to preterm labor and transverse lie. The newborn with ambiguous genitalia was delivered but expired after birth. Autopsy findings revealed alobar holoprosencephaly, a prominent forehead, hypotelorism, an absent nose, absent bilateral ears, median cleft lip and palate, preaxial polydactyly of the right hand, accessory spleens, single umbilical artery, markedly enlarged adrenal glands and ambiguous external genitalia The subsequent fetal chromosomal study revealed 46,XX.</p> <p>Conclusion</p> <p>We describe a case of diabetic fetopathy with classic facial malformation and preaxial hallucal polydactyly which has been proposed as a marker of diabetic embryopathy. Bilateral adrenal hyperplasia with ambiguous genitalia, an uncommon associated anomaly, was also identified. It is controversial whether adrenal hyperplasia can be a novel feature of diabetic fetopathy or just a coincidental finding. Further observation and adequate investigation are needed in such cases.</p

    A core outcome set for studies of gestational diabetes mellitus prevention and treatment

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    AIMS/HYPOTHESIS: The aim of this systematic review was to develop core outcome sets (COSs) for trials evaluating interventions for the prevention or treatment of gestational diabetes mellitus (GDM). METHODS: We identified previously reported outcomes through a systematic review of the literature. These outcomes were presented to key stakeholders (including patient representatives, researchers and clinicians) for prioritisation using a three-round, e-Delphi study. A priori consensus criteria informed which outcomes were brought forward for discussion at a face-to-face consensus meeting where the COS was finalised. RESULTS: Our review identified 74 GDM prevention and 116 GDM treatment outcomes, which were presented to stakeholders in round 1 of the e-Delphi study. Round 1 was completed by 173 stakeholders, 70% (121/173) of whom went on to complete round 2; 84% (102/121) of round 2 responders completed round 3. Twenty-two GDM prevention outcomes and 30 GDM treatment outcomes were discussed at the consensus meeting. Owing to significant overlap between included prevention and treatment outcomes, consensus meeting stakeholders agreed to develop a single prevention/treatment COS. Fourteen outcomes were included in the final COS. These consisted of six maternal outcomes (GDM diagnosis, adherence to the intervention, hypertensive disorders of pregnancy, requirement and type of pharmacological therapy for hyperglycaemia, gestational weight gain and mode of birth) and eight neonatal outcomes (birthweight, large for gestational age, small for gestational age, gestational age at birth, preterm birth, neonatal hypoglycaemia, neonatal death and stillbirth). CONCLUSIONS/INTERPRETATION: This COS will enable future GDM prevention and treatment trials to measure similar outcomes that matter to stakeholders and facilitate comparison and combination of these studies. TRIAL REGISTRATION: This study was registered prospectively with the Core Outcome Measures in Effectiveness Trials (COMET) database: http://www.comet-initiative.org/studies/details/686/
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