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Late Gestation (late + gestation)
Selected AbstractsSuppression of the Febrile Response in Late Gestation: Evidence, Mechanisms and OutcomesJOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2008A. Mouihate Fever is a beneficial host defence response. However, fever caused by the immune stimulant, lipopolysaccharide (LPS), are attenuated in many species during pregnancy, particularly near term. A number of parallel mechanisms may be responsible, and these vary in magnitude according to the time of gestation, type of inflammatory stimulus and species of animal. Some studies report a reduction in the plasma levels of circulating pro-inflammatory cytokines such as tumour necrosis factor-,, interleukin-1, and interleukin-6 along with increased levels of anti-inflammatory cytokines such as interleukin-1 receptor antagonist. Associated with the attenuated febrile response to LPS is a reduction in the activation of the prostaglandin synthesising enzyme, cyclo-oxygenase 2, resulting in reduced levels of the obligatory prostaglandin mediators of the febrile response in the brain. There is also a reduction in the sensitivity of the brain to the pyrogenic action of prostaglandins, which does not appear to be due to a change in the levels of hypothalamic EP3 prostaglandin receptors. The suppression of fever at term may be important for the health of the neonate because fever in pregnant mothers may be harmful to the late-term foetus and neonate. [source] 24-Hour Secretion Patterns of Plasma Oestradiol 17, in Pony Mares in Late GestationREPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2003LJ O'Donnell Contents The mare exhibits nocturnal uterine contractions in the last 6 days of gestation. It is hypothesized that estradiol 17, (O17,) may be associated with the nightly increase in uterine contractions. The 24-h secretion pattern of plasma O17, was measured in 3 pony mares in late gestation to identify changes in release as the mare neared parturition. Blood was collected weekly at 08:00 hours beginning on day 240 and every third day from day 330 until delivery. Serial blood samples were collected from each mare every 30-min for 24-h beginning on gestation day 310 and every sixth day thereafter until parturition. Concentrations of O17, were elevated at night with lowest concentrations occurring directly before sunset (p < 0.01). The natural log of the variance was increased at sunset (p < 0.01) and was decreased during the 6-h period immediately after sunrise. This pattern was especially evident in the 6 days that preceded parturition. The contrast between nocturnal and daytime concentrations of O17, in the last 6 days of gestation may contribute to night-time delivery in the mare. [source] Development of olfactory epithelium in the human fetus: Scanning electron microscopic observationsCONGENITAL ANOMALIES, Issue 3 2009Mitsuhiro Kimura ABSTRACT Aims:, Human olfactory epithelium becomes functional at birth, but prenatal development remains unclear. In the present study, we aimed to clarify the development of human olfactory epithelium using scanning electron microscopy (SEM). Methods:, The development of human olfactory epithelium was observed in 24 externally normal fetuses, which were formalin-fixed and long-preserved, with a crown-rump length (CRL) of 102,336 mm (gestational week 14,38). The olfactory mucosa in the superior wall of the nasal septum near the choana were dissected and observed under SEM. We examined the number of olfactory vesicles per unit area, diameter of olfactory vesicles, and number and length of cilia on olfactory vesicles. Results:, At circa (ca) CRL 100 mm (ca 14 weeks), olfactory epithelium displayed several olfactory vesicles with 1,2 short cilia per unit area. At ca CRL 150 mm (ca 18 weeks), olfactory vesicles were present in small clusters, and cilia were longer. At CRL lager than 225 mm (ca 26 weeks), olfactory vesicles became located separately from each other, while length and number of cilia per olfactory vesicle were further increased. Conclusion:, The present findings suggest that fetal olfactory epithelium becomes morphologically almost the same as that in adults in late gestation, much later than previously thought. [source] Expression, functional, and structural analysis of proteins critical for otoconia developmentDEVELOPMENTAL DYNAMICS, Issue 10 2010Yinfang Xu Abstract Otoconia, developed during late gestation and perinatal stages, couple mechanic force to the sensory hair cells in the vestibule for motion detection and bodily balance. In the present work, we have investigated whether compensatory deposition of another protein(s) may have taken place to partially alleviate the detrimental effects of Oc90 deletion by analyzing a comprehensive list of plausible candidates, and have found a drastic increase in the deposition of Sparc-like 1 (aka Sc1 or hevin) in Oc90 null versus wt otoconia. We show that such up-regulation is specific to Sc1, and that stable transfection of Oc90 and Sc1 full-length expression constructs in NIH/3T3 cells indeed promotes matrix calcification. Analysis and modeling of Oc90 and Sc1 protein structures show common features that may be critical requirements for the otoconial matrix backbone protein. Such information will serve as the foundation for future regenerative purposes. Developmental Dynamics 239:2659,2673, 2010. © 2010 Wiley-Liss, Inc. [source] Screening for gestational diabetes; past, present and futureDIABETIC MEDICINE, Issue 5 2002F. W. F. Hanna Abstract Gestational diabetes is carbohydrate intolerance, with onset or first recognition of hyperglycaemia during pregnancy. Several studies have suggested that gestational hyperglycaemia is associated with adverse maternal and fetal outcomes, promoting the case for screening. Conversely, others argue that screening for gestational diabetes may colour the clinical judgement, influencing further management, e.g. more ,unjustified' caesarean sections. Additionally, the lack of definitive data either on a clear-cut glycaemic threshold for the development of adverse outcomes or on the impact of intervention is emphasized by opponents of screening. This review attempts to evaluate the available data on screening for gestational diabetes. Oral glucose tolerance test is promoted on the basis that the diabetogenic stress of pregnancy is encountered during late gestation and is best recognized in the fed state. There are different tests, including the 1 h/50-g, 2 h/75-g and 3 h/100-g tests, with practical limitations, including the time and cost involved and the unpleasant supra-physiological glucose load that is unrelated to body weight, and issues of reproducibility and sensitivity/specificity profiles. Despite its convenience, the poor sensitivity of random glucose has precluded its routine use for screening. Fasting glucose appears to be promising but further testing is required to ensure satisfactory sensitivity/specificity in different populations. Despite its limitations, the oral glucose tolerance test has become established as the ,most acceptable' diagnostic test for gestational diabetes. More convenient methods, e.g. fasting or random or post-load glucose, have to be validated therefore against the oral glucose tolerance test to gain acceptance for routine screening. Diabet. Med 19, 351,358 (2002) [source] Complications of late gestation in the mareEQUINE VETERINARY EDUCATION, Issue S5 2002G. S. Frazer First page of article [source] Introducing a mouse model for pre-eclampsia: adoptive transfer of activated Th1 cells leads to pre-eclampsia-like symptoms exclusively in pregnant miceEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2004Abstract Pre-eclampsia (PE) is the most severe pregnancy-related disease, leading to high maternal and fetal morbidity/mortality. Immunological imbalances associated with endothelial cell dysfunction have been hypothesized as a cause for the onset and perpetuation of PE. Valid and reliable animal models are urgently required to test this hypothesis and to better understand the mechanisms underlying PE. We developed a novel PE-model by adoptively transferring activated BALB/c Th1-like splenocytes into allogeneically pregnant BALB/c female mice during late gestation; the model mimicked the symptoms of PE, i.e. increased blood pressure and glomerulonephritis accompanied by proteinuria. Interestingly, these PE-like symptoms were not detectable in non-pregnant recipients of activated Th1-like cells. Adoptive cell transfer adversely affected the outcome of pregnancy by increasing fetal rejection, with uterine immune cells showing an inflammatory profile. In conclusion, we have established a valid and reliable PE mouse model, which opens vast opportunities for therapeutic interventions. [source] Conditional alleles of Msx1 and Msx2,GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 8 2007Hualin Fu Abstract The msh-related homeobox genes, Msx1 and Msx2, have a variety functions during murine organogenesis, Msx1 in the development of the palate and teeth, Msx2 in the skull, teeth, and skin. Msx1 mutants die perinatally. Compound Msx1-2 mutants do not survive past late gestation. The multiplicity of functions of Msx1 and 2, as well as the lethality of Msx1 and Msx1-2 mutants limits the utility of the conventional knockouts. We therefore produced conditional alleles of Msx1 and Msx2. We constructed targeting vectors with LoxP sites flanking the homeodomain-encoding second exons and Frt sites flanking a neo gene. These vectors were used to produce targeted ES cells and mice with floxed alleles. The functionality of the LoxP sites in the floxed alleles was established by crosses with K14-Cre mice (epidermis-specific), and with an Msx2 -Cre line that produces a germline deletion. Analysis of progeny by PCR revealed correct Cre-mediated recombination, as well as expected phenotypes. genesis 45:477,481, 2007. Published 2007 Wiley-Liss, Inc. [source] Maternal depression and anxiety effects on the human fetus: Preliminary findings and clinical implications,INFANT MENTAL HEALTH JOURNAL, Issue 5 2008John N.I. Dieter Newborns of depressed and anxious mothers show biobehavioral abnormalities suggesting that maternal psychological distress has negative effects on the fetus. Two studies examined the fetuses of depressed and nondepressed mothers: (a) a cross-sectional investigation of fetal activity during the second and third trimesters and (b) an examination of behavioral and heart rate response to vibratory stimulation in late-gestation fetuses. Fetuses of depressed mothers were more active during the fifth, sixth, and seventh gestational months. Assessment of late-term fetuses consisted of a baseline, trials of vibratory stimulation directed towards measuring habituation, and a poststimulation period. During baseline, the fetuses of depressed mothers exhibited a lower heart rate. During stimulation trials, they showed less total movement and appeared to habituate more often. Approximately 35% of the variance in fetal behavior was accounted for by the mothers' depression and anxiety symptoms. Maternal depression may be linked to greater fetal activity during the second and third trimesters and decreased behavioral responsivity during late gestation. The response of late-term fetuses of depressed mothers to vibratory stimulation may reflect "receptor adaptation/effector fatigue" and not true habitation. Future studies should examine the value of clinical interventions provided to the pregnant mother. [source] Plasma vitamin A status in calves fed colostrum from cows that were fed vitamin A during late pregnancyJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 5 2008G. Puvogel Summary Calves are born vitamin A and ,-carotene deficient and the ,-carotene conversion to vitamin A is limited. Colostrum, contains relatively large amounts of vitamin A and ,-carotene and the retinol and ,-carotene status of calves can be normalized with colostrum consumption. We studied whether vitamin A supplementation of cows during late gestation (dry period) increases cow plasma retinol concentrations, the retinol content of first colostrum, and the plasma vitamin A status of calves during their first month of life. Both plasma and colostrum retinol concentrations were higher in vitamin A supplemented cows than in non-supplemented cows. In calves that were for 5 days fed colostrum (milk) from vitamin A-supplemented cows and then mature milk, plasma retinol concentrations were higher from 14 to 30 days after birth than in calves that were fed colostrum (milk) from cows that were not vitamin A supplemented. The study shows that vitamin A supplementation of cows during the dry period can improve the vitamin A status of their calves up to 1 month, if calves ingest their colostrum/milk for up to 5 days. [source] Metabolic changes during the perinatal period in dairy sheep in relation to level of nutrition and breed.JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-4 2000Summary The effect of level of nutrition during pregnancy was investigated on various plasma parameters, on energy intake, body weight, energy balance and milk yield, after parturition in two Greek dairy breeds. Thirteen Chios (CH) and 17 Karagouniko (K) pregnant ewes were assigned to groups A and B, which received 110% of their energy requirements for maintenance plus pregnancy for two foetuses and 90% of their maintenance energy requirements, respectively. After parturition all ewes were fed ad libitum. Body weights of group A and K ewes were higher (p 0.05) compared with group B and CH ewes, during lactation, although daily energy intakes tended to be greater in group B than in A ewes, during the first 3 weeks and in CH than K ewes (p 0.05), after the second week post-partum. Total mean milk production was 114 ± 11 l and 82 ± 10 l for groups A and B (p 0.05) and 120 ± 12 l and 70 ± 7 l for CH and K ewes (p 0.001), respectively. Positive energy balance appeared after the day 15 and 7 of lactation, for groups A and B ewes and after the day 15 and 5 of lactation, for CH and K ewes, respectively. The group B and K ewes tended to have higher mean plasma glucose concentrations than group A and CH ewes, during early lactation. There were no significant differences in free fatty acids, ,-hydroxybutyric acid, insulin and T4 concentrations between A and B ewes. CH had higher free fatty acids (p 0.05) and ,-hydroxybutyric acid (p 0.05), and lower T4 (p 0.01) and insulin (p 0.05) concentrations than K ewes. It was concluded that under-nutrition during pregnancy results in low milk yields of ewes fed ad libitum in early lactation, due to the poor development of the udder during late gestation. [source] Central Regulation of the Hypothalamic-Pituitary-Adrenal Axis During Fetal Development in the Guinea-PigJOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2005D. Owen Abstract We have previously shown that the foetal guinea-pig hypothalamic-pituitary-adrenal (HPA) axis is activated near the time of parturition and that this is associated with changes in limbic glucocorticoid receptors (GR) and mineralocorticoid receptors. In the present study, we hypothesized that the foetal hypothalamic paraventricular nucleus (PVN) and pituitary contribute significantly to foetal HPA drive but that these areas remain sensitive to negative feedback by circulating glucocorticoids in late gestation. However, we observed decreased corticotrophin-releasing hormone mRNA expression in the PVN and decreased pro-opiomelanocortin (POMC) mRNA levels in the anterior pituitary with advanced gestational age. The reduction in POMC mRNA expression was likely the result of negative feedback via circulating glucocorticoids because GR mRNA was unchanged during development in the foetal pituitary. Furthermore, we found that maternally administered glucocorticoids significantly decreased foetal pituitary POMC mRNA expression in a dose-dependent manner at gestational day (gd) 62 with male foetuses being more sensitive to these effects. These findings show that the foetal HPA axis remains highly sensitive to glucocorticoid feedback even as plasma adrenocorticotropic hormone and cortisol levels are elevated at the end of gestation. [source] Fetal Exposure to Moderate Ethanol Doses: Heightened Operant Responsiveness Elicited by Ethanol-Related ReinforcersALCOHOLISM, Issue 11 2009Samanta M. March Background:, Prenatal exposure to moderate ethanol doses during late gestation modifies postnatal ethanol palatability and ingestion. The use of Pavlovian associative procedures has indicated that these prenatal experiences broaden the range of ethanol doses capable of supporting appetitive conditioning. Recently, a novel operant technique aimed at analyzing neonatal predisposition to gain access to ethanol has been developed. Experiment 1 tested the operant conditioning technique for developing rats described by Arias and colleagues (2007) and Bordner and colleagues (2008). In Experiment 2, we analyzed changes in the disposition to gain access to ethanol as a result of moderate prenatal exposure to the drug. Methods:, In Experiment 1, newborn pups were intraorally cannulated and placed in a supine position that allowed access to a touch-sensitive sensor. Paired pups received an intraoral administration of a given reinforcer (milk or quinine) contingent upon physical contact with the sensor. Yoked controls received similar reinforcers only when Paired pups activated the circuit. In Experiment 2, natural reinforcers (water or milk) as well as ethanol (3% or 6% v/v) or an ethanol-related reinforcer (sucrose compounded with quinine) were tested. In this experiment, pups had been exposed to water or ethanol (1 or 2 g/kg) during gestational days 17 to 20. Results:, Experiment 1 confirmed previous results showing that 1-day-old pups rapidly learn an operant task to gain access to milk, but not to gain access to a bitter tastant. Experiment 2 showed that water and milk were highly reinforcing across prenatal treatments. Furthermore, general activity during training was not affected by prenatal exposure to ethanol. Most importantly, prenatal ethanol exposure facilitated conditioning when the reinforcer was 3% v/v ethanol or a psychophysical equivalent of ethanol's gustatory properties (sucrose,quinine). Conclusions:, The present results suggest that late prenatal experience with ethanol changes the predisposition of the newborn to gain access to ethanol-related stimuli. In conjunction with prior literature, this study emphasizes the fact that intrauterine experience with ethanol not only augments ethanol's palatability and ingestion, but also facilitates the acquisition of response,stimulus associations where the drug acts as an intraoral reinforcer. [source] Fetal Learning With Ethanol: Correlations Between Maternal Hypothermia During Pregnancy and Neonatal Responsiveness to Chemosensory Cues of the DrugALCOHOLISM, Issue 5 2004Paula Abate Abstract: Background: Fetuses learn about ethanol odor when the drug is present in the amniotic fluid. Prenatal learning comprising ethanol's chemosensory cues also suggests an acquired association between ethanol's chemosensory and postabsorptive properties. Ethanol-related thermal disruptions have been implicated as a significant component of the drug's unconditioned properties. In the present study, ethanol-induced thermal changes were analyzed in pregnant rats subjected to a moderate ethanol dose. This thermal response was later tested for its correlation with the responsiveness of the progeny to ethanol and nonethanol chemosensory stimuli. Methods: During gestational day (GD) 14, pregnant rats were subjected to a minor surgical procedure to place a subcutaneous telemetric thermal sensor in the nape of the neck. During GDs 17 to 20, females received a daily intragastric administration of ethanol (2 g/kg) or water, using solutions kept at room temperature. Maternal body temperatures were recorded before and after (4 consecutive hours) the administration of water or ethanol. Newborns representative of both prenatal treatments were tested in terms of behavioral activity elicited by the smell of ethanol or of a novel odorant (cineole). A third group of pups were tested in response to unscented air stimulation. Results: Ethanol administration during late gestation induced reliable maternal hypothermia, a thermal disruption greater than that observed in water-treated females. It was systematically observed that maternal ethanol-induced hypothermia negatively correlated with neonatal motor reactivity elicited by ethanol olfactory stimulation. No other significant correlations were observed in terms of responsiveness to cineole or to unscented air in animals prenatally exposed to ethanol or water. Conclusions: In conjunction with prior research, the present results indicate that fetal ethanol exposure may yield learning of an association between ethanol's sensory and unconditioned properties. Ethanol-induced hypothermia during late gestation seems to represent a significant component of ethanol's unconditioned consequences. Specifically, ethanol-related thermal disruptions in the womb are highly predictive of neonatal responsiveness to ethanol's chemosensory cues that are known to be processed by the near-term fetus. [source] Perceived health of adults after prenatal exposure to the Dutch faminePAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 4 2003Tessa J. Roseboom Summary People who were undernourished in early gestation are more obese, have a more atherogenic lipid profile, and altered blood coagulation and seem to have an increased risk of coronary heart disease. We now report on whether they also feel less healthy. We therefore assessed the perceived health of 50-year-old-men and women born alive as singletons around the time of the Dutch famine in the Wilhelmina Gasthuis in Amsterdam. People who had been exposed to famine in early gestation, but not those exposed in mid- or late gestation, more often rated their health as poor (10.3% vs. to 4.9% in the unexposed, odds ratio (OR) 2.2 [1.0, 4.8]). The effect of exposure to famine in early gestation on perceived health could only partly be explained by an increased prevalence of coronary heart disease, respiratory diseases, hypertension, type 2 diabetes, hypercholesterolaemia or cancer (adjusted OR 2.2 [0.9, 5.2]). Adjustment for adult risk factors (BMI, LDL/HDL cholesterol ratio, blood pressure, smoking, lung function) also attenuated the results to some extent (adjusted OR 1.9 [0.6, 5.5]). People who were exposed to famine in early gestation were not only less healthy in terms of objective measures of health but they also felt less healthy. Because poor perceived health is a strong predictor of mortality, we may expect increased mortality in people who were exposed to famine in early gestation in the future. [source] Effects of fetal growth restriction on lung development before and after birth: A morphometric analysisPEDIATRIC PULMONOLOGY, Issue 3 2001G.S. Maritz PhD Abstract Our aim was to determine the effects of fetal growth restriction (FGR) during late gestation on the structure of the lungs in the fetus near term and at 8 weeks after birth. The studies were performed using two groups of pregnant sheep and their offspring. In both groups, FGR was induced by umbilico-placental embolisation (UPE); for fetal studies, UPE was performed from 120 days of gestation until 140 days (term, ,146 days), when fetuses were killed for tissue analysis. For postnatal studies, UPE continued from 120 days until delivery at term; postnatal lambs were killed at 8 weeks after birth for tissue analysis. UPE led to a thicker pulmonary blood-air barrier at 140 days of gestation and this difference, which was due to a thickened basement membrane, was still present at 8 weeks after birth. At 8 weeks, we also observed a smaller number of alveoli per respiratory unit, thicker interalveolar septa, and a greater volume density of lung tissue in FGR lambs compared to controls. These changes would be expected to impair gas exchange and alter the mechanical properties of the lungs. Our data show that structural alterations in the lungs induced by placental insufficiency were more evident at 8 weeks of postnatal age than near term, indicating that the effects of FGR on the lung may become more serious with age and may affect respiratory health later in life. Pediatr Pulmonol. 2001; 32:201,210. © 2001 Wiley-Liss, Inc. [source] Boys live dangerously in the wombAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2010Johan G. Eriksson The growth of every human fetus is constrained by the limited capacity of the mother and placenta to deliver nutrients to it. At birth, boys tend to be longer than girls at any placental weight. Boy's placentas may therefore be more efficient than girls, but may have less reserve capacity. In the womb boys grow faster than girls and are therefore at greater risk of becoming undernourished. Fetal undernutrition leads to small size at birth and cardiovascular disorders, including hypertension, in later life. We studied 2003 men and women aged around 62 years who were born in Helsinki, Finland, of whom 644 had hypertension: we examined their body and placental size at birth. In both sexes, hypertension was associated with low birth weight. In men, hypertension was also associated with a long minor diameter of the placental surface. The dangerous growth strategy of boys may be compounded by the costs of compensatory placental enlargement in late gestation. In women, hypertension was associated with a small placental area, which may reduce nutrient delivery to the fetus. In men, hypertension was linked to the mothers' socioeconomic status, an indicator of their diets: in women it was linked to the mothers' heights, an indicator of their protein metabolism. Boys' greater dependence on their mothers' diets may enable them to capitalize on an improving food supply, but it makes them vulnerable to food shortages. The ultimate manifestation of their dangerous strategies may be that men have higher blood pressures and shorter lives than women. Am. J. Hum. Biol., 2010. © 2009 Wiley-Liss, Inc. [source] Molecular prenatal diagnosis for hereditary distal arthrogryposis type 2BPRENATAL DIAGNOSIS, Issue 5 2007Miao Jiang Abstract Autosomal dominant distal arthrogryposes (DAs) are a group of muscle diseases characterized by congenital contractures of the limbs. Currently, prenatal diagnosis of DAs depends upon ultrasound examination during late gestation. Recently, five genes encoding fast switch proteins located at 9p13.2, 11p15.5 and 17q13.1 were identified. These included TPM2, TNNI2/TNNT3, and MYH3/MYH8. Last year, we discovered a novel heterozygous mutation c.523_525delAAG (p.K175del) in the TNNI2 gene, which encodes the isoform of troponinI, in a seven-generation Chinese family affected with distal arthrogryposis type 2B (DA2B). Here, we report the molecular prenatal diagnosis of 3 high-risk fetuses of two women in the family by two-point linkage inferential analysis and deletion detection of the TNNI2 gene with chorionic villus sampling (CVS) or amniocentesis. To our knowledge, this is the first description of molecular prenatal diagnosis for DAs. Copyright © 2007 John Wiley & Sons, Ltd. [source] Assessment of fetal lung development by quantitative ultrasonic tissue characterization: a methodical studyPRENATAL DIAGNOSIS, Issue 9 2004Ismail Tekesin Abstract Objectives This study was performed to evaluate the quantitative ultrasonic tissue characterization of the normal fetal lung development by using acoustic raw data captured after preprocessing. Methods One hundred and sixty-two patients with completed gestational ages between 22 and 37 weeks were enrolled in this study. Longitudinal and transverse sections of the fetal thorax and upper abdomen were imaged. A region of interest of constant size was defined and the tissue-specific gray scale was determined by using an interactive software. Results A total of 162 patients met the inclusion criteria. The echogenicity of the fetal lung showed a particular changing pattern during pregnancy: the mean gray value of the fetal lung (MGV) is almost the same as the MGV of the fetal liver at 22 and 23 weeks, decreases between 22 and 31 weeks and increases between 31 and 37 weeks. The MGV of the fetal liver decreases significantly from 24 weeks to 31 weeks and increases significantly again toward 37 weeks. We stated that the MGV of the lung is smaller than the MGV of the liver during 31 weeks of gestation and the relation reverses in late gestation. At term, the MGV of the liver is greater than the MGV of the lung. The lung-to-liver ratio is <1 between 24 and 29 weeks and >1 between 30 and 35 weeks. Conclusion The echogenicity of the fetal lung showed a particular changing pattern during pregnancy, which corresponds to morphologic changes of the fetal lung development. Copyright © 2004 John Wiley & Sons, Ltd. [source] 24-Hour Secretion Patterns of Plasma Oestradiol 17, in Pony Mares in Late GestationREPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2003LJ O'Donnell Contents The mare exhibits nocturnal uterine contractions in the last 6 days of gestation. It is hypothesized that estradiol 17, (O17,) may be associated with the nightly increase in uterine contractions. The 24-h secretion pattern of plasma O17, was measured in 3 pony mares in late gestation to identify changes in release as the mare neared parturition. Blood was collected weekly at 08:00 hours beginning on day 240 and every third day from day 330 until delivery. Serial blood samples were collected from each mare every 30-min for 24-h beginning on gestation day 310 and every sixth day thereafter until parturition. Concentrations of O17, were elevated at night with lowest concentrations occurring directly before sunset (p < 0.01). The natural log of the variance was increased at sunset (p < 0.01) and was decreased during the 6-h period immediately after sunrise. This pattern was especially evident in the 6 days that preceded parturition. The contrast between nocturnal and daytime concentrations of O17, in the last 6 days of gestation may contribute to night-time delivery in the mare. [source] Long-term effects of a midgestational asphyxial episode in the ovine fetusTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 10 2006Amanda E. O'Connell Abstract We and others have shown previously that fetuses at midgestation can survive 30 min of complete umbilical cord occlusion, although hydrops fetalis (or gross fetal edema) results. To investigate whether this hydrops resolves by late gestation and if there are any long-term consequences of the asphyxial insult on the heart and kidneys, eight fetuses were subjected to 30 min of complete umbilical cord occlusion at 0.6 gestation (90 days; term 150 days) and were compared to a sham group (n = 10). During the occlusion period, fetuses became severely hypoxemic, hypercapnemic, and acidotic, with both blood pressure and heart rate decreasing. Most variables had returned to normal by 2-hr recovery. At 129 ± 1 days of gestation, approximately 40 days post occlusion, some fetuses were still slightly hydropic as skin fold measurements were increased (P < 0.01), although fetal body weight was not different from the sham group. The two groups had similar heart and kidney weights, ventricular cardiac myocyte nucleation, and glomerular number. By contrast, brain weight was reduced by 37% (P < 0.001) and the cerebral lateral ventricles were grossly dilated. Lungs were 50% smaller than in sham fetuses (P < 0.001). Thus, the hydrops that develops at midgestation as a result of a severe asphyxial episode can, but does not always, fully resolve by late gestation. Also, while fetuses at midgestation can survive this asphyxial episode with no long-term impact in renal or cardiac size, nephron number, or cardiomyocyte nucleation, the brain and lungs are severely affected. Anat Rec Part A, 288A:1112,1120, 2006. © 2006 Wiley-Liss, Inc. [source] Mechanical ventilatory constraints during incremental cycle exercise in human pregnancy: implications for respiratory sensationTHE JOURNAL OF PHYSIOLOGY, Issue 19 2008Dennis Jensen The aim of this study was to identify the physiological mechanisms of exertional respiratory discomfort (breathlessness) in pregnancy by comparing ventilatory (breathing pattern, airway function, operating lung volumes, oesophageal pressure (Poes)-derived indices of respiratory mechanics) and perceptual (breathlessness intensity) responses to incremental cycle exercise in 15 young, healthy women in the third trimester (TM3; between 34 and 38 weeks gestation) and again 4,5 months postpartum (PP). During pregnancy, resting inspiratory capacity (IC) increased (P < 0.01) and end-expiratory lung volume decreased (P < 0.001), with no associated change in total lung capacity (TLC) or static respiratory muscle strength. This permitted greater tidal volume (VT) expansion throughout exercise in TM3, while preserving the relationship between contractile respiratory muscle effort (tidal Poes swing expressed as a percentage of maximum inspiratory pressure (PImax)) and thoracic volume displacement (VT expressed as a percentage of vital capacity) and between breathlessness and ventilation . At the highest equivalent work rate (HEWR = 128 ± 5 W) in TM3 compared with PP: , tidal Poes/PImax and breathlessness intensity ratings increased by 10.2 l min,1 (P < 0.001), 8.8%PImax (P < 0.05) and 0.9 Borg units (P < 0.05), respectively. Pulmonary resistance was not increased at rest or during exercise at the HEWR in TM3, despite marked increases in mean tidal inspiratory and expiratory flow rates, suggesting increased bronchodilatation. Dynamic mechanical constraints on VT expansion (P < 0.05) with associated increased breathlessness intensity ratings (P < 0.05) were observed near peak exercise in TM3 compared with PP. In conclusion: (1) pregnancy-induced increases in exertional breathlessness reflected the normal awareness of increased and contractile respiratory muscle effort; (2) mechanical adaptations of the respiratory system, including recruitment of resting IC and increased bronchodilatation, accommodated the increased VT while preserving effort,displacement and breathlessness, relationships; and (3) dynamic mechanical ventilatory constraints contributed to respiratory discomfort near the limits of tolerance in late gestation. [source] Adaptations in placental nutrient transfer capacity to meet fetal growth demands depend on placental size in miceTHE JOURNAL OF PHYSIOLOGY, Issue 18 2008P. M. Coan Experimental reduction in placental growth often leads to increased placental efficiency measured as grams of fetus produced per gram of placenta, although little is known about the mechanisms involved. This study tested the hypothesis that the smallest placenta within a litter is the most efficient at supporting fetal growth by examining the natural intra-litter variation in placental nutrient transfer capacity in normal pregnant mice. The morphology, nutrient transfer and expression of key growth and nutrient supply genes (Igf2P0, Grb10, Slc2a1, Slc2a3, Slc38a1, Slc38a2 and Slc38a4) were compared in the lightest and heaviest placentas of a litter at days 16 and 19 of pregnancy, when mouse fetuses are growing most rapidly in absolute terms. The data show that there are morphological and functional adaptations in the lightest placenta within a litter, which increase active transport of amino acids per gram of placenta and maintain normal fetal growth close to term, despite the reduced placental mass. The specific placental adaptations differ with age. At E16, they are primarily morphological with an increase in the volume fraction of the labyrinthine zone responsible for nutrient exchange, whereas at E19 they are more functional with up-regulated placental expression of the glucose transporter gene, Slc2a1/GLUT1 and one isoform the System A family of amino acid transporters, Slc38a2/SNAT2. Thus, this adaptability in placental phenotype provides a functional reserve capacity for maximizing fetal growth during late gestation when placental growth is compromised. [source] Role of leptin in the regulation of growth and carbohydrate metabolism in the ovine fetus during late gestationTHE JOURNAL OF PHYSIOLOGY, Issue 9 2008Alison J. Forhead Leptin is an important regulator of appetite and energy expenditure in adulthood, although its role as a nutritional signal in the control of growth and metabolism before birth is poorly understood. This study investigated the effects of leptin on growth, carbohydrate metabolism and insulin signalling in fetal sheep. Crown,rump length-measuring devices and vascular catheters were implanted in 12 sheep fetuses at 105,110 days of gestation (term 145 ± 2 days). The fetuses were infused i.v. either with saline (0.9% NaCl; n= 6) or recombinant ovine leptin (0.5,1.0 mg kg,1 day,1; n= 6) for 5 days from 125 to 130 days when they were humanely killed and tissues collected. Leptin receptor mRNA and protein were expressed in fetal liver, skeletal muscle and perirenal adipose tissue. Throughout infusion, plasma leptin in the leptin-infused fetuses was 3- to 5-fold higher than in the saline-infused fetuses, although plasma concentrations of insulin, glucose, lactate, cortisol, catecholamines and thyroid hormones did not differ between the groups. Leptin infusion did not affect linear skeletal growth or body, placental and organ weights in utero. Hepatic glycogen content and activities of the gluconeogenic enzymes glucose-6-phosphatase and phosphoenolpyruvate carboxykinase in the leptin-infused fetuses were lower than in the saline-infused fetuses by 44, 48 and 36%, respectively; however, there were no differences in hepatic glycogen synthase activity or insulin signalling protein levels. Therefore, before birth, leptin may inhibit endogenous glucose production by the fetal liver when adipose energy stores and transplacental nutrient delivery are sufficient for the metabolic needs of the fetus. These actions of leptin in utero may contribute to the development of neonatal hypoglycaemia in macrosomic babies of diabetic mothers. [source] Effects of twin pregnancy and periconceptional undernutrition on maternal metabolism, fetal growth and glucose,insulin axis function in ovine pregnancyTHE JOURNAL OF PHYSIOLOGY, Issue 5 2008C. W. H. Rumball Although twins have lower birthweights than singletons, they may not experience the increased disease risk in adulthood reportedly associated with low birthweight. In contrast, another periconceptional event, maternal undernutrition, does not reduce birthweight but does affect fetal and postnatal physiology in sheep. We therefore studied maternal and fetal metabolism, growth and glucose,insulin axis function in late gestation in twin and singleton sheep pregnancies, either undernourished from 60 days before until 30 days after conception or fed ad libitum. We found that twin-bearing ewes had decreased maternal food intake in late gestation and lower maternal and fetal plasma glucose and insulin levels. Twin fetuses had fewer everted placentomes, grew slower in late gestation, and had a greater insulin response to a glucose challenge, but lesser response to arginine. In contrast, periconceptional undernutrition led to increased maternal food intake and a more rapid fall in maternal glucose levels in response to fasting. Periconceptional undernutrition increased the number of everted placentomes, and abolished the difference in insulin responses to glucose between twins and singletons. Thus, the physiology of twin pregnancy is quite different from that of singleton pregnancy, and is probably determined by a combination of factors acting in both early and late gestation. The inconsistency of the relationships between low birthweight and postnatal disease risk of twins may lie in their very different fetal development. These data suggest that twin pregnancy may be another paradigm of developmental programming, and indicate that twins and singletons must be examined separately in any study of fetal or postnatal physiology. [source] Short periods of prenatal stress affect growth, behaviour and hypothalamo,pituitary,adrenal axis activity in male guinea pig offspringTHE JOURNAL OF PHYSIOLOGY, Issue 3 2005Amita Kapoor Prenatal stress can have profound long-term influences on physiological function throughout the course of life. We hypothesized that focused periods of moderate prenatal stress at discrete time points in late gestation have differential effects on hypothalamo,pituitary,adrenal (HPA) axis function in adult guinea pig offspring, and that changes in HPA axis function will be associated with modification of anxiety-related behaviour. Pregnant guinea pigs were exposed to a strobe light for 2 h on gestational days (GD) 50, 51, 52 (PS50) or 60, 61, 62 (PS60) (gestation length ,70 days). A control group was left undisturbed throughout pregnancy. Behaviour was assessed in male offspring on postnatal day (PND)25 and PND70 by measurement of ambulatory activity and thigmotaxis (wall-seeking behaviour) in a novel open field environment. Subsequent to behavioural testing, male offspring were cannulated (PND75) to evaluate basal and activated HPA axis function. Body weight was significantly decreased in adult PS50 and PS60 offspring and this effect was apparent soon after weaning. The brain-to-body-weight ratio was significantly increased in adult PS50 males. Basal plasma cortisol levels were elevated in PS50 male offspring throughout the 24 h sampling period compared with controls. In response to an ACTH challenge and to exposure to an acute stressor, PS60 male offspring exhibited elevated plasma cortisol responses. Plasma testosterone concentrations were strikingly decreased in PS50 offspring. Thigmotaxis in the novel environment was increased in PS50 male offspring at PND25 and PND70, suggesting increased anxiety in these animals. In conclusion, prenatal stress during critical windows of neuroendocrine development programs growth, HPA axis function, and stress-related behaviour in adult male guinea pig offspring. Further, the nature of the effect is dependant on the timing of the maternal stress during pregnancy. [source] Impact of glucose infusion on the structural and functional characteristics of adipose tissue and on hypothalamic gene expression for appetite regulatory neuropeptides in the sheep fetus during late gestationTHE JOURNAL OF PHYSIOLOGY, Issue 1 2005B. S. Mühlhäusler In the present study, our aim was to determine whether intrafetal glucose infusion increases fetal adiposity, synthesis and secretion of leptin and regulates gene expression of the ,appetite regulatory' neuropeptides neuropepetide Y (NPY), agouti-related peptide (AGRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) and receptors (leptin receptor (OB-Rb) and melancortin 3 receptor (MC3R)) within the fetal hypothalamus. Glucose (50% dextrose in saline) or saline was infused (7.5 ml h,1) into fetal sheep between 130 and 140 days gestation (term = 150 ± 3 days gestation). Glucose infusion increased circulating glucose and insulin concentrations, mean lipid locule size (532.8 ± 3.3 ,m2versus 456.7 ± 14.8 ,m2) and total unilocular fat mass (11.7 ± 0.6 g versus 8.9 ± 0.6 g) of the perirenal fat depot. The expression of OB-Rb mRNA was higher in the ventromedial nucleus compared to the arcuate nucleus of the hypothalamus in both glucose and saline infused fetuses (F= 8.04; P < 0.01) and there was a positive correlation between expression of OB-Rb and MC3R mRNA in the arcuate nucleus (r= 0.81; P < 0.005). Glucose infusion increased mRNA expression for POMC, but not for the anorectic neuropeptide CART, or the orexigenic neuropeptides NPY and AGRP, in the arcuate nucleus of the fetal hypothalamus. These findings demonstrate that increased circulating glucose and insulin regulate gene expression of the neuropeptides within the fetal hypothalamus that are part of the neural network regulating energy balance in adult life. [source] Effects of low dose dexamethasone treatment on basal cardiovascular and endocrine function in fetal sheep during late gestationTHE JOURNAL OF PHYSIOLOGY, Issue 2 2002Andrew J. W. Fletcher This study investigated the effects on ovine fetal basal cardiovascular and endocrine functions of fetal intravenous dexamethasone treatment, resulting in circulating concentrations that were one-fifth of the values measured clinically in human infants following maternal antenatal glucocorticoid therapy. Between 117-120 days gestation (dGA; term: ca 145 dGA), 26 Welsh Mountain sheep fetuses were surgically prepared under general anaesthesia with vascular catheters and a Transonic flow probe positioned around a femoral artery. At 125 ± 1 dGA, fetuses were infused with dexamethasone (2.06 ± 0.13 ,g kg,1 h,1i.v.; n= 13) or saline (n= 13) for 48 h. Daily fetal arterial blood samples were taken and cardiovascular data were recorded continuously (data acquisition system). Pressor, vasoconstrictor and chronotropic responses to exogenously administered doses of phenylephrine, angiotensin II and arginine vasopressin (AVP) were determined at 124 ± 1 (pre-infusion), 126 ± 1 (during infusion) and 128 ± 1 (post-infusion) dGA. Fetal cardiac baroreflex curves were constructed using peak pressor and heart rate responses to phenylephrine. Dexamethasone treatment elevated fetal mean arterial blood pressure by 8.1 ± 1.0 mmHg (P < 0.05), increased femoral vascular resistance by 0.65 ± 0.12 mmHg (ml min,1),1 (P < 0.05), depressed plasma noradrenaline concentrations and produced a shift in set-point, but not sensitivity, of the cardiac baroreflex (P < 0.05). Elevations in fetal arterial blood pressure, but not femoral vascular resistance and the shift in baroreflex set-point, persisted at 48 h following dexamethasone treatment. By 48 h following dexamethasone infusion, basal plasma noradrenaline concentration was restored, whilst plasma adrenaline and neuropeptide Y (NPY) concentrations were enhanced, compared with controls (P < 0.05). Fetal dexamethasone treatment did not alter the fetal pressor or femoral vasoconstrictor responses to adrenergic, vasopressinergic or angiotensinergic agonists. These data show that fetal treatment with low concentrations of dexamethasone modifies fetal basal cardiovascular and endocrine functions. Depending on the variable measured, these changes may reverse, persist or become enhanced by 48 h following the cessation of treatment. [source] Effects of LPS and IL-6 on Oxytocin Receptor in Non-Pregnant and Pregnant Rat UterusAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 2 2000XIN FANG PROBLEM: Little is known regarding the regulation of the timing of parturition. Recent evidence suggests an interaction between the immune system and uterine contractility in late gestation. METHOD: Pregnant rats were treated with LPS in vivo in attempts to establish a model of premature parturition induced by the pro-inflammatory response. Uterine explants were incubated in vitro to determine the effects of IL-6 on uterine synthesis of oxytocin (OT) and its receptor (OTR). RESULTS: LPS injection was quite toxic to pregnant rats and gave extremely variable results. In animals that delivered, there was a marked increase in the uterine concentrations of OTR and OTR mRNA. There was no consistent effect regarding the timing of parturition. IL-6 caused a significant increase in the concentration of OTR mRNA in uterine explants from pregnant rats but not in tissues from non-pregnant animals. CONCLUSION: Rat uterine concentrations of OTR are regulated by IL-6. Pro-inflammatory cytokines may stimulate uterine contractility in late gestation rat uterine tissues through a mechanism involving stimulation of OTR. [source] Effects of dietary glucose level during late gestation on litter performance and glucose concentration in sowsANIMAL SCIENCE JOURNAL, Issue 1 2009Young-Keun HAN ABSTRACT The effects of feeding glucose during the 5 days before parturition on litter performance and on glucose concentration in sows were studied. At day 100 of gestation, 130 multiparous sows were assigned to the treatments. Late gestating sows were fed 0 g, 150 g, 250 g, 350 g and 450 g of glucose a day, respectively. During lactation, all sows were given free access to the same lactation diet (without glucose). One day before parturition, blood samples were collected from 30 sows (6 sows per treatment) at 10 before and 20, 40, 60 and 80 min after the meal. The supply of additional dietary glucose increased piglet birth weight (P < 0.05). Feed intake in week 1 and week 1,4 of lactation was greatest in sows fed the 0% glucose diet, least by sows fed the 18% glucose diet, and intermediate by sows fed the 6, 10, 14% glucose diets (P < 0.05). Basal glucose concentration and time of maximum glucose concentration after glucose intake were not affected by dietary treatment in the last 5 days of gestation. The sows fed the 14 and 18% glucose diets had greater maximum increase in glucose concentration than sows fed diet without glucose (P < 0.05). In conclusion, feeding glucose to sows during 5 days before parturition increased birth weight of live-born piglet and decreased sows feed intake during lactation, but did not affect the performance of sows and piglets. [source] | |||||||||||||