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PubMed1998

The generation of human gammadelta T cell repertoires during fetal development.

The nature of how human gammadelta T cells are normally generated is not clear. We have used an RT-PCR assay and DNA sequencing to identify and compare delta-encoded TCRs (TCRDs) that are generated de novo in the fetal gut, liver, and thymus and to determine when, where, and how the TCRD repertoire is established during normal embryonic development. Rearranged TCRDV genes are first expressed outside of the thymus in the liver and primitive gut between 6 and 9 wk gestation. Although DV1Rs and/or DV2Rs predominated, differences in the pattern of TCRDV gene rearrangement and transcription in each tissue during ontogeny were identified. Specific, DV2-encoded TCRs are highly conserved throughout ontogeny in the tissues from the same and between genetically distinct donors. Although the thymic and intestinal gammadelta T cell repertoires partially overlap early in development, they diverge and become nonoverlapping during the second trimester, and the generation of the intestinal gammadelta T cell repertoire is characterized by differences in the processing of DV1Rs and DV2Rs. Whereas the structural diversity of DV1Rs progressively increases during gut development up to birth, DV2Rs have limited structural diversity throughout ontogeny. Together, our findings provide evidence for the ability of different fetal tissues to support the development of gammadelta T cells.

Animals↗
PubMed2005

Fish consumption in pregnancy and omega-3 status after birth are not associated with postnatal depression.

BACKGROUND: Research to date suggests a relationship between fish consumption, omega-3 polyunsaturated fatty acids, and depression. However, interpretation of this research is difficult due to methodological limitations. Postpartum women provide an excellent opportunity to examine these relationships because omega-3s are transferred from mother to fetus during pregnancy and from mother to child after birth through breast milk. Hence new mothers are more likely to be depleted in omega-3s. Our aim was to determine whether prenatal fish consumption and omega-3 status after birth were associated with postnatal depression. METHODS: Eighty first-time mothers were recruited; 41 who scored on or over the cut-off on one of two depression-screening instruments, and 39 in the control group. Depression was diagnosed using the Composite International Diagnostic Interview. Fish consumption was measured during pregnancy, and depression and omega-3 status were determined postnatally. Logistic regression and t-tests were used to examine relationships between fish consumption, omega-3 status, and postnatal depression, while controlling for known covariates. RESULTS: Prenatal fish consumption was not predictive of postnatal depression, and postnatal omega-3 status was not associated with postnatal depression. However, prenatal fish consumption did predict omega-3 status after birth. LIMITATIONS: Prenatal fish consumption was measured using only a food frequency questionnaire, and no participants consumed oily fish (rich in omega-3s) regularly. CONCLUSIONS: There was no association between postnatal depression and either fish consumption in early pregnancy, or omega-3 status after birth. Our findings make it difficult to justify trials of omega-3 polyunsaturated fatty acids in the treatment of postnatal depression.

Adult↗
PubMed1988

Diffusion approximation and first-passage-time problem for a model neuron. III. A birth-and-death process approach.

A stochastic model for single neuron's activity is constructed as the continuous limit of a birth-and-death process in the presence of a reversal hyperpolarization potential. The resulting process is a one dimensional diffusion with linear drift and infinitesimal variance, somewhat different from that proposed by Lánský and Lánská in a previous paper. A detailed study is performed for both the discrete process and its continuous approximation. In particular, the neuronal firing time problem is discussed and the moments of the firing time are explicitly obtained. Use of a new computation method is then made to obtain the firing p.d.f. The behaviour of mean, variance and coefficient of variation of the firing time and of its p.d.f. is analysed to pinpoint the role played by the parameters of the model. A mathematical description of the return process for this neuronal diffusion model is finally provided to obtain closed form expressions for the asymptotic moments and steady state p.d.f. of the neuron's membrane potential.

Membrane Potentials↗
PubMed2006

The interrelation of birth weight and regional lipid deposition: a twins study.

This study examined the hypothesis that low birth weight is associated with changes in regional lipid deposition as well as insulin sensitivity in adult twins. Eleven adult female twin pairs were studied by magnetic resonance to determine regional adiposity. Their insulin sensitivity was assessed by the homeostasis model assessment. There were significant associations between birth weight and current homeostasis model assessment value (r=-0.528, P=.012), abdominal visceral (r=-0.581, P=.005), and subcutaneous fat volumes (r=-0.638, P=.001) if the group of 22 subjects were analyzed as individuals. There were no significant associations of the intratwin pair difference in birth weight and differences between adult twins in these same variables possibly because of limited patient numbers. Reduced birth weight does confer an increased risk of abdominal adiposity as well as insulin resistance in twin populations as it does in the general population.

Abdominal Fat↗
PubMed1988

Congenital malformations and intrauterine growth retardation: a population study.

The relationship between congenital malformations and intrauterine growth retardation was investigated using data from the population-based Metropolitan Atlanta Congenital Defects Program. Between 1970 and 1984, the system ascertained 13,074 infants with major structural malformations diagnosed in the first year of life and born to metropolitan Atlanta residents. These infants were classified as having intrauterine growth retardation if their birth weight was below the race-, sex-, and gestational age-specific tenth percentile limits for all Atlanta births. Overall, the frequency of intrauterine growth retardation among malformed infants was 22.3% (relative risk 2.6). Of 48 defect categories evaluated, 46 were associated with excess intrauterine growth retardation, most notably chromosomal anomalies (eg, 83.7% for infants with trisomy 18, relative risk 46) and anencephaly (73.3%, relative risk 25). Only a few isolated defects (such as isolated polydactyly, pyloric stenosis, and congenital hip dislocation) were not associated with excess intrauterine growth retardation. Among infants with multiple malformations, the frequency of intrauterine growth retardation increased markedly with increasing number of defects--from 20% for infants with two defects to 60% for infants with nine or more defects. The relationship between malformations and intrauterine growth retardation can be explained by one or more of three mechanisms: (1) intrauterine growth retardation can be a secondary disturbance to the presence of malformations; (2) intrauterine growth retardation can predispose the fetus to malformations; and (3) intrauterine growth retardation can coexist with malformations because of common etiologic factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Anencephaly↗
PubMed1987

Limit theorems for the population size of a birth and death process allowing catastrophes.

The linear birth and death process with catastrophes is formulated as a right continuous random walk on the non-negative integers which evolves in continuous time with an instantaneous jump rate proportional to the current value of the process. It is shown that distributions of the population size can be represented in terms of those of a certain Markov branching process. The ergodic theory of Markov branching process transition probabilities is then used to develop a fairly complete understanding of the behaviour of the population size of the birth-death-catastrophe process.

Animals↗
PubMed2003

Zinc supplementation and growth of the fetus and low birth weight infant.

Zinc deficiency limits growth in young children, and in animal models it also affects fetal growth. In animals, the effect of severe zinc deficiency on growth is evident. However, controlled trials of zinc supplementation during pregnancy in humans have not demonstrated consistent effects on weight at birth and/or duration of gestation. Those studies that have identified a positive effect of zinc on fetal growth were performed on low-socioeconomic or migrant groups in industrialized countries or in countries where diet and living conditions are improving. In contrast, in studies conducted either on populations with minimal risk of zinc deficiency or those suffering from multiple and severe nutritional deficiencies, no effects have been found. The potential confounding factors that may help explain the contradictory results include the following: age of pregnant women; presence of digestive diseases, other nutritional deficiencies, phytates or other factors that affect bioavailability; timing and duration of zinc supplementation and compliance with supplements. Few studies of zinc supplementation were conducted on infants that were born small for their gestational age or preterm; in this case, a positive effect on growth was shown. A study of zinc supplementation during pregnancy found reduced risk of diseases (diarrhea or impetigo) in small-for-gestational-age but not preterm infants. A second study demonstrated reduced mortality in small-for-gestational-age infants. We conclude that supplementation trials during human pregnancy do not provide conclusive evidence for a beneficial effect of zinc supplementation despite the experimental evidence that zinc deficiency may retard fetal growth or shorten pregnancy. However, early zinc supplementation in low birth weight or small-for-gestational-age infants reveals an effective improvement in growth, which suggests a prenatal depletion or insufficient zinc intake to support catch-up growth postnatally.

Animals↗
PubMed1994

Survival and short-term outcome in newborns of 23 to 25 weeks' gestation.

OBJECTIVES: We determined which factors are associated with survival and good short-term neurologic outcome in newborns of 23 to 25 weeks' gestation. STUDY DESIGN: We retrospectively reviewed the charts of all (n = 82) infants born alive at our hospital at 23 to 25 weeks' gestation from 1988 through 1991. We used univariate and multiple logistic regression analysis to compare survivors at hospital discharge with nonsurvivors and those with and without good short-term neurologic outcome. RESULTS: Survival rates were 19%, 59%, and 65% at 23, 24, and 25 weeks' gestation, respectively. A total of 90% of survivors had good short-term neurologic outcome. On multiple logistic regression analysis, female sex (odds ratio 8.7, 95% confidence limits 2.2 and 34), larger birth weight (odds ratio 2.5 per 100 gm increment, 95% confidence limits 1.3 and 4.9), and more advanced gestational age (odds ratio 5.3, 95% confidence limits 1.2 and 22 for 24 weeks; odds ratio 3.8, 95% confidence limits 0.6 and 22 for 25 weeks) were associated with survival. Female sex, more advanced gestational age, and larger birth weight were also associated with good short-term neurologic outcome. CONCLUSIONS: Good short-term neurologic outcome is possible in many survivors in this gestational age range. Factors other than gestational age may be considered when intervention in these pregnancies is contemplated.

Birth Weight↗
PubMed2005

Tubal flushing for subfertility.

BACKGROUND: A possible therapeutic effect of diagnostic tubal patency testing has been debated in the literature for half a century. Further debate surrounds whether oil-soluble or water-soluble contrast media might have the bigger fertility-enhancing effect. Historically a variety of agents have been used to 'flush' the fallopian tubes, although tubal flushing does not currently form part of routine practice in the treatment of fertility delay. OBJECTIVES: To evaluate the effect of flushing a woman's fallopian tubes with oil- or water-soluble contrast media on subsequent fertility outcomes in couples with infertility. SEARCH STRATEGY: We searched the Cochrane Menstrual Disorders and Subfertility Group's specialised register of trials (searched 2 March 2004), MEDLINE (1966 to Mar 2004), EMBASE (1980 to Mar 2004), Biological Abstract (1980 to Mar 2004) and reference lists of articles. SELECTION CRITERIA: All randomised trials where tubal flushing with oil-soluble contrast media or tubal flushing with water-soluble media was compared with one another or with no treatment were considered for inclusion in the review. DATA COLLECTION AND ANALYSIS: Eleven randomised controlled trials were identified and included in this review. All trials were assessed for quality criteria. The studied primary outcome was live birth (and ongoing pregnancy), with secondary outcomes pregnancy, miscarriage, ectopic pregnancy, treatment complications including pain, intravasation of contrast medium, infection and haemorrhage, and image quality. MAIN RESULTS: Tubal flushing with oil-soluble media versus no intervention (three trials including 381 participants) was associated with a significant increase in the odds of live birth (Peto OR 2.98, 95%CI 1.40 to 6.37) and of pregnancy (Peto OR 3.30, 95%CI 2.00 to 5.43). There were no data from RCTs to assess tubal flushing with water-soluble media versus no intervention. For the comparison of tubal flushing with oil-soluble media versus tubal flushing with water-soluble media (six trials including 1,483 participants), the increase in the odds of live birth for tubal flushing with oil-soluble versus water-soluble media (Peto OR 1.49, 95%CI 1.05 to 2.11) was based on two trials where statistical heterogeneity was present and the higher quality trial showed no significant difference; there was no evidence of a significant difference in the odds of pregnancy (Peto OR 1.24, 95%CI 0.97 to 1.57). The addition of oil-soluble media to flushing with water-soluble media (water-soluble plus oil-soluble media versus water-soluble media alone; three trials including 555 participants) showed no evidence of a significant difference in the odds of pregnancy (Peto OR 1.18, 95%CI 0.82 to 1.70) or live birth (Peto OR 1.06, 95%CI 0.64 to 1.77). Adverse event data were only available for the comparison OSCM versus WSCM: OSCM carried a significantly higher chance of intravasation (Peto OR 5.41, 95%CI 2.57 to 11.37) but a significantly lower chance of immediate pain (Peto OR 0.53, 95%CI 0.34 to 0.84), prolonged pain (Peto OR 0.26, 95%CI 0.15 to 0.45) and post-procedure bleeding (Peto OR 0.22, 95%CI 0.15 to 0.31), and no serious adverse events were reported. AUTHORS' CONCLUSIONS: There is evidence of effectiveness of tubal flushing with oil-soluble contrast media in increasing the odds of pregnancy and live birth versus no intervention. The limited evidence of an increase in the odds of live birth from tubal flushing with oil-soluble contrast media versus water-soluble contrast media must be interpreted cautiously. Further robust randomised trials, comparing oil-soluble versus water-soluble media and comparing water-soluble media versus no intervention, would be a useful further guide to clinical practice. Further research is merited to ascertain the mechanism of the fertility enhancing effect of oil-soluble media, as to whether this is a 'tubal flushing' phenomenon, an effect on the intraperitoneal environment, or an implantation enhancing effect on the endometrium.

Contrast Media↗
PubMed2006

Validity of self-reported use of assisted reproductive technology treatment among women participating in the Pregnancy Risk Assessment Monitoring System in five states, 2000.

OBJECTIVES: To assess the validity of a question on assisted reproductive technology (ART) incorporated into the Pregnancy Risk Assessment Monitoring System (PRAMS) in 2000. While the intent of the question is to ascertain whether the index infant was conceived using ART, the phrasing was ambiguous for women who had used ART while trying to conceive the index infant but became pregnant after discontinuing treatment. METHODS: We compared weighted PRAMS estimates from five states that incorporated the ART question in 2000 with data from the U.S. ART Surveillance System (ART-SS) maintained by the Centers for Disease Control and Prevention (CDC). U.S. medical practices are mandated to report data for every ART procedure to CDC annually; thus, the ART-SS is highly specific and complete. RESULTS: ART use was reported for 156 of the PRAMS births in our study population, representing 4,571 (95% Confidence Limit, 3,452-5,690) births from the total birth cohort in the five states of interest in 2000. For the same maternal residency states and year, 1,768 births were reported to the ART-SS. Thus, we calculate that PRAMS overestimated ART use by 2,803 births. PRAMS estimated 2.59 times as many ART births as reported to the ART-SS. While for singletons, a large excess in estimated births from PRAMS was observed (ratio=3.50), there was little difference between the PRAMS estimates and ART-SS for twin and triplet births. CONCLUSION: These findings suggest women responding to PRAMS may be reporting past ART use in addition to current. The findings by plurality support this hypothesis.

Birth Weight↗
PubMed1993

The causes of cerebral palsy. Recent evidence.

Cerebral palsy (CP), unlike many other neurodevelopmental disorders, is associated with abnormalities of pregnancy and birth, particularly 'birth asphyxia' and low birthweight. Associations, however, need not be causal, and some prenatally damaged infants manifest clinical signs suggestive of birth asphyxia in the perinatal period. The lack of a clinically reliable indicator of impaired fetal-placental gas exchange limits our confidence that birth asphyxia plays a true causal role in cerebral palsy. Premature delivery is the single most important antecedent of cerebral palsy, and the increase in survival of very small infants resulting from newborn intensive care may augment this contribution in the future. Cranial ultrasound imaging can describe patterns of neonatal brain damage in the low birthweight infant that are highly predictive of later cerebral palsy. Future research on the causes of cerebral palsy may benefit from improvements in the neurological assessment of the fetus prior to labor and from a clearer understanding of the role of endocrine factors, particularly thyroid disorders, in neurologic development.

Asphyxia Neonatorum↗
PubMed1997

Effective priming of neonates born to immune dams against the immunogenic pseudorabies virus glycoprotein gD by replication-incompetent adenovirus-mediated gene transfer at birth.

One of the main limitations of the vaccination of neonates from vaccinated or infected mothers is the interference by inherited maternal antibodies, which are known to inhibit the immune response against both live and inactivated vaccines. The efficiency of bypassing this inhibition by the transfer of an immunogenic glycoprotein gene, the gD gene of pseudorabies virus (PRV), into neonates was explored. The experiments were conducted in 1-day-old piglets, which are immunocompetent at birth. The same transcription unit (gD of PRV under the control of the adenovirus major late promoter) was delivered intramuscularly at birth either in the form of naked DNA or cloned in the genome of a replication-defective adenovirus. A booster injection of a conventional live PRV vaccine strain was given at 10 weeks of age, the replication of which was greatly restricted by the residual amounts of colostral antibodies in control animals. Piglets were challenged at the age of 16 weeks with a virulent PRV strain. The replication-defective adenovirus was able to efficiently prime piglets born to immune dams against gD in such a way that inoculation with the Bartha strain protected them against a subsequent challenge with the same level of efficacy in piglets born to naive or immune dams. In contrast, piglets born to immune dams into which the gD gene was not transferred, or transferred as naked DNA at birth, were not protected. These results open the way for early immunization of neonates born to vaccinated or infected mothers.

Adenoviridae↗
PubMedDate not supplied

Expression of the P2X7 receptor subunit of the adenosine 5'-triphosphate-gated ion channel in the developing and adult rat cochlea.

ATP-gated ion channels assembled from P2X(7) subunits have been implicated in ontogeny and cellular pathology. Here, the expression of the P2X(7) receptor subunit was studied in the embryonic (E14-E18 days) and postnatal (P0-adult) rat cochlea using immunohistochemistry. Strong P2X(7) immunolabelling was observed in the primary auditory neurons of the spiral ganglion from E18 to adult and in the fibres innervating the sensory inner and outer hair cells from birth to adult. Strong immunolabelling of P2X(7) receptor protein was also observed in the inner and outer hair cells over a limited developmental period, from birth to P6. Weak expression was observed in cochlear duct epithelium on E18 and in the supporting cells (footplates of pillar cells in adult and in Böttcher's cells after birth). The immunolocalisation of P2X(7) receptors further implicates extracellular ATP in signalling process in cochlear ontogeny and in establishment and function of auditory neurotransmission. The P2X(7) receptors may be involved in signal transduction and modulation as well as in regulating cell death during development and in pathological conditions.

Adenosine Triphosphate↗
PubMed2003

Brn3c null mutant mice show long-term, incomplete retention of some afferent inner ear innervation.

BACKGROUND: Ears of Brn3c null mutants develop immature hair cells, identifiable only by certain molecular markers, and undergo apoptosis in neonates. This partial development of hair cells could lead to enough neurotrophin expression to sustain sensory neurons through embryonic development. We have therefore investigated in these mutants the patterns of innervation and of expression of known neurotrophins. RESULTS: At birth there is a limited expression of BDNF and NT-3 in the mutant sensory epithelia and DiI tracing shows no specific reduction of afferents or efferents that resembles neurotrophin null mutations. At postnatal day 7/8 (P7/8), innervation is severely reduced both qualitatively and quantitatively. 1% of myosin VIIa-positive immature hair cells are present in the mutant cochlea, concentrated in the base. Around 20% of immature hair cells exist in the mutant vestibular sensory epithelia. Despite more severe loss of hair cells (1% compared to 20%), the cochlea retains many more sensory neurons (46% compared to 15%) than vestibular epithelia. Even 6 months old mutant mice have some fibers to all vestibular sensory epithelia and many more to the cochlear apex which lacks MyoVIIa positive hair cells. Topologically organized central cochlea projections exist at least until P8, suggesting that functional hair cells are not required to establish such projections. CONCLUSION: The limited expression of neurotrophins in the cochlea of Brn3c null mice suffices to support many sensory neurons, particularly in the cochlea, until birth. The molecular nature of the long term survival of apical spiral neurons remains unclear.

Age Factors↗
PubMed2006

The limitations on choice: Palestinian women's childbirth location, dissatisfaction with the place of birth and determinants.

BACKGROUND: Analysing the Palestinian Central Bureau of Statistics (PCBS) Demographic and Health Survey 2004 (DHS-2004) data, this article focuses on the question of where women living in the Occupied Palestinian Territory give birth, and whether it was the preferred/place of choice for delivery. We further identify some of the determinants of women's dissatisfaction with childbirth location. METHODS: A total of 2158 women residing in the West Bank and Gaza Strip were included in this study. Regression analysis established the association between dissatisfaction with the place of birth and selected determinants. RESULTS: A total of 3.5% of women delivered at home, with the rest in assisted facilities. Overall, 20.5% of women reported that their childbirth location was not the preferred place of delivery. Women who delivered at home; in governmental facilities; in regions other than the central West Bank; who had sudden delivery or did not reach their preferred childbirth location because of closures and siege; because of costs/the availability of insurance; or because there were no other locations available, were significantly more likely to be dissatisfied with their childbirth location compared to those who birthed in private facilities, the central West Bank, and in locations with better and more available services. CONCLUSION: The findings demonstrate that Palestinian women's choice of a place of birth is constrained and modified by the availability, affordability, and limited access to services induced by continuing closures and siege. These findings need to be taken into consideration when planning for maternity services in the Occupied Palestinian Territory.

Adolescent↗