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At least 253 records · Page 14Linked to original sources
PubMed2006

Maternal dietary (n-3) fatty acid deficiency alters neurogenesis in the embryonic rat brain.

Docosahexaenoic acid [22:6(n-3)] is enriched in brain membrane phospholipids and essential for brain function. Neurogenesis during embryonic and fetal development requires synthesis of large amounts of membrane phospholipid. We determined whether dietary (n-3) fatty acid deficiency during gestation alters neurogenesis in the embryonic rat brain. Female rats were fed diets with 1.3% energy [(n-3) control] or 0.02% energy [(n-3) deficient], from alpha-linolenic acid [18:3(n-3)], beginning 2 wk before gestation. Morphometric analyses were performed on embryonic day 19 to measure the mean thickness of the neuroepithelial proliferative zones corresponding to the cerebral cortex (ventricular and subventricular zones) and dentate gyrus (primary dentate neuroepithelium), and the thickness of the cortical plate and sectional area of the dentate gyrus. Phospholipids and fatty acids were determined by HPLC and GLC. Docosahexaenoic acid was 55-65% lower and (n-6) docosapentaenoic acid [22:5(n-6)] was 150-225% higher in brain phospholipids at embryonic day 19 in the (n-3) deficient (n = 6 litters) than in the control (n = 5 litters) group. The mean thickness of the cortical plate and mean sectional area of the primordial dentate gyrus were 26 and 48% lower, respectively, and the mean thicknesses of the cortical ventricular zone and the primary dentate neuroepithelium were 110 and 70% higher, respectively, in the (n-3) deficient than in the control embryonic day 19 embryos. These studies demonstrate that (n-3) fatty acid deficiency alters neurogenesis in the embryonic rat brain, which could be explained by delay or inhibition of normal development.

Animals↗
PubMed2000

[Fetal exposure to endocrine disruptors].

Endocrine disruptors act to alter blood hormone levels or the subsequent action of hormones. Disturbances of hormonal regulation during fetal or postnatal development in human may induce adverse effects, but these adverse effects of endocrine disruptors on humans are subtle. We investigated fetal exposure to endocrine disruptors in Japan by analyzing umbilical cords or cord sera. Many endocrine disruptors including dioxins, polychlorinated biphenyls, organochlorine pesticides, bisphenol A, nonylphenol and phytoestrogen were detected in umbilical cords and cord sera. Here we summarize the present status of fetal exposure to endocrine disruptors in Japan and other countries.

Child Development↗
PubMed2004

The effect of divergent selection for uterine capacity on fetal and placental development at term in rabbits: maternal and embryonic genetic effects.

The aim of this work was to study the effects of the genotype of the dam, the embryo, or their interactions on prenatal growth by performing double-reciprocal embryo transfers between two lines of rabbits divergently selected for uterine capacity. Females from high (n = 53) and low (n = 48) lines were slaughtered at 72 h of gestation, and recovered embryos were transferred to the oviducts of recipient does from the high (n = 23) and low (n = 19) lines. Each recipient doe received eight embryos from the high line into one oviduct and eight embryos from the low line into the other. Recipient does were slaughtered on d 28 of gestation. The percentages of live fetuses at 28 d of gestation were 89.2 and 74% for high and low recipient lines, respectively. Length and weight of the empty uterine horn and weight of the full uterine horn were not affected by either the recipient or by donor line. Fetal weight was affected by the recipient line but not by the donor line. Fetuses gestated in high recipient does were 7% heavier (P < 0.10) than those in the low recipient does. There was a donor and a donor x recipient interaction effect on fetal placental weight. Fetal placental weight was heavier (7%, P < 0.01) for embryos from the low line. Embryos from the high line gestated in low-line uteri showed a lower fetal placenta weight than did low-line embryos gestated in high-line uteri and low-line uteri (P < 0.05). Linear regression coefficients of fetal weight at term on fetal placental weights differed (P < 0.05) for the high and low donors (4.33 +/- 0.28 and 3.41 +/- 0.29 respectively). A significant effect of the donor genotype on individual placental length was observed (P < 0.05), which might have resulted from a smaller individual placental length of low-line embryos gestated high-line uteri (P < 0.10). Neither donor nor recipient lines affected maternal placental weight or available space for fetuses. Fetuses and their fetal placentae were heavier when receiving more than four blood vessels than when receiving less than three blood vessels (13 and 17% respectively, P < 0.05). Neither recipient nor donor genotype affected the number of blood vessels arriving at each live fetus. Thus, fetal weight depends on the maternal genotype, whereas fetal placental weight depends on the embryo genotype in these two lines of rabbits divergently selected for uterine capacity.

Animals↗
PubMed1997

Relationship between concentration of serum leptin and fetal growth.

The serum leptin concentration reflects the amount of adipose tissue in the body. Although fat deposition in the fetus in the third trimester markedly increases, the role of leptin during pregnancy has not been clarified. In the present study, whether or not the serum leptin concentration correlates with growth in utero was investigated, in addition to how leptin levels change in the first few days after birth. One hundred sixteen Japanese infants were divided into term (n = 91) and preterm groups (n = 25). Term infants were divided into 3 subgroups: birth weight appropriate for gestational age (AGA) (n = 44), birth weight large for gestational age (LGA) (n = 28), and birth weight small for gestational age (SGA) (n = 19). Longitudinal changes in the concentration of serum leptin after birth were examined in 48 infants. The serum leptin concentration was determined by RIA. No significant difference in leptin levels between cord sera and infants' sera obtained within the first 6 h of life (n = 28) was observed. Within the first 6 h of life, the concentration of serum leptin in LGA infants (12.8 +/- 10.2 ng/mL) and SGA infants (1.6 +/- 1.1 ng/mL) was significantly higher and lower, respectively, than that in the AGA infants (4.4 +/- 3.0 ng/mL) (P < 0.01). A significant positive correlation was found between the leptin concentration within 6 h of life and birth body weight (r = 0.59, P < 0.01). After birth, the concentration of leptin in LGA and AGA infants significantly decreased to the level in SGA infants within 72 h [corrected] of delivery (P < 0.05). After 72 h [corrected] of life, no significant differences in the concentration of leptin were observed among the three groups, and low levels continued to 7 days of age. These findings indicate that serum level of leptin correlates with fetal body weight gain.

Adult↗
PubMed1995

Myogenin is required for late but not early aspects of myogenesis during mouse development.

Mice with a targeted mutation in the myogenic basic helix-loop-helix regulatory protein myogenin have severe muscle defects resulting in perinatal death. In this report, the effect of myogenin's absence on embryonic and fetal development is investigated. The initial events of somite differentiation occurred normally in the myogenin-mutant embryos. During primary myogenesis, muscle masses in mutant embryos developed simultaneously with control siblings, although muscle differentiation within the mutant muscle masses was delayed. More dramatic effects were observed when secondary myofibers form. During this time, very little muscle formation took place in the mutants, suggesting that the absence of myogenin affected secondary myogenesis more severely than primary myogenesis. Monitoring mutant neonates with fiber type-specific myosin isoforms indicated that different fiber types were present in the residual muscle. No evidence was found to indicate that myogenin was required for the formation of muscle in one region of the embryo and not another. The expression patterns of a MyoD-lacZ transgene in myogenin-mutant embryos demonstrated that myogenin was not essential for the activation of the MyoD gene. Together, these results indicate that late stages of embryogenesis are more dependent on myogenin than early stages, and that myogenin is not required for the initial aspects of myogenesis, including myotome formation and the appearance of myoblasts.

Animals↗
PubMed2002

Studies of 50 Hz circularly polarized magnetic fields of up to 350 microT on reproduction and embryo-fetal development in rats: exposure during organogenesis or during preimplantation.

Groups of mated female Sprague-Dawley rats were simultaneously exposed to 0 (sham exposed), 7, 70, or 350 microT (rms) circularly polarized 50 Hz magnetic fields (MF) for 22 h/day on gestational day 8-15, the period of rat fetal organogenesis (organogenesis study) or from day 0 to day 7 of gestation, the rat preimplantation period (preimplantation study). Developmental toxicity was assessed on gestational day 20. Identical experiments were repeated to confirm reproducibility of both studies. In both studies, statistically significant differences between exposed and sham exposed animals were observed in several measured parameters; however, these differences only appeared in one, but not both replicate experiments and generally at only an isolated exposure level. Because these differences were not reproducible and did not show a dose response relationship, they were not considered related to MF exposure. In the organogenesis study, lower kidney weights of dams were seen at 70 and 350 microT in Experiment 1. Lower dam liver weights and lower mean body weights of viable female and male fetuses were seen at 70 microT in Experiment 2. Otherwise, there were no differences in these parameters or in group means for fetal loss after implantation, number of viable fetuses, fetal body weight and sex ratio, incidences of external, visceral, and skeletal abnormalities or variations, or tissue abnormalities after histopathological examination. In the preimplantation study, dam health and indices for reproduction and embryo-fetal development, including pre or postimplantation loss, number and body weight of live fetuses, and sex ratio, external, skeletal abnormalities and variations, and skeletal ossification did not differ. Dam inorganic phosphorous concentration at 350 microT was elevated in one experiment and depressed in another. In one experiment, visceral abnormalities, primarily thymic remnant in neck and accessory liver lobe, were increased in the 7 microT group. Based on these results from two studies, we conclude that circularly polarized 50 Hz MF exposure of up to 350 microT during the fetal organogenesis or during the preimplantation period does not affect reproduction and embryo-fetal development in Sprague-Dawley rats.

Animals↗
PubMedDate not supplied

Tibiofibular torsion from the fetal period until birth.

The anatomic findings of Le Damany and Dupuis are still valuable as a reference. However, their measurement of tibial torsion does not correspond to clinical conditions. In fact, the torsion of the tibiofibular functional unit corresponds to the angle between the transverse axis of the proximal tibial epiphyseal plate and the axis through the middle of both malleoli. A comparative morphologic, radiologic, computerized axial tomographic and anatomic study performed on 50 fetuses with this definition has shown different results. Tibiofibular torsion was in the clear lateral position from the beginning of the fetal period, with a positive gradient at birth.

Anthropometry↗
PubMed1980

Embryogenesis and prenatal development of congenital vertebral anomalies and their classification.

Vertebral anomalies were studied in 144 patients. The specific anatomic defects were defined by serial roentgenograms: anterior approaches were used in 42 operations and posterior approaches in 74 operations. Growth features of the spine were examined histologically in 15 embryos and fetuses ranging in length from 6 to 120 mm. After an extensive review of the literature on normal human spine embryology and fetal development, and after defining the specific vertebral anatomic defects and their pathogenesis, some new concepts of congenital vertebral anomalies formation are proposed. Old concepts are found to be inadequate in light of our current knowledge of embryogenesis. The authors' new and all-inclusive classification of congenital vertebral anomalies is based on specific defects, pathogenesis, and time for origin in embryonic or fetal development.

Female↗
PubMed1999

Developmental expression of N-acetyltransferases in C57BI/6 mice.

N-Acetyltransferases (NATs) play an important role in the biotransformation of a wide variety of arylamine drugs and carcinogens. Two genes (NAT1, NAT2) have been identified and allelic variation in NAT2 has been associated with arylamine toxicity in adults. Little information has been reported on expression of NAT genes during embryonic and fetal development although substrate specific NAT activity has been detected. The current study investigated the expression of NAT1 and NAT2 in mice pre-and postnatally. RNA was isolated from maternal liver, embryonic tissue at gestational days (GD) 10, 15, and 18, or neonates at neonatal day 3. Reverse transcription-polymerase chain reaction was performed using primers designed to amplify portions of either the NAT1 or the NAT2 gene. NAT1 and NAT2 mRNAs were detected in the embryo/placental complex at GD 10 and in GD 15 and 18 embryos. NAT2 but not NAT1 was expressed in GD 18 and neonatal day 3 hepatic tissue. These data demonstrate the differential expression of NAT genes in the mouse embryo and suggest a potential role for NAT in development.

Acetyltransferases↗
PubMed2003

Genomic organization and embryonic expression of Igsf8, an immunoglobulin superfamily member implicated in development of the nervous system and organ epithelia.

Igsf8 is an immunoglobulin protein that binds to the tetraspanin molecules, CD81 and CD9. We describe the genomic organization of mouse and human Igsf8, and reveal a dynamic expression pattern during embryonic and fetal development. Igsf8 is first expressed at E9.5 in a ventral domain of the neural tube, with dorsal expression apparent at E10.5. We show that the ventral, but not the dorsal, domain of neural tube expression is dependent on Shh signaling. From E11.5, Igsf8 is expressed at the lateral edge of the ventricular zone, in early postmitotic neuroblasts, and in dorsal root and cranial ganglia. Igsf8 is also expressed in the branchial arches, dorsal pancreatic primordium, neural retina, olfactory epithelium, gut, kidney, and lung.

Animals↗
PubMed1981

Vinyl chloride: inhalation teratology study in mice, rats and rabbits.

These studies evaluated the effects of inhaled vinyl chloride monomer (VCM) on mouse, rat and rabbit embryonal and fetal development. Groups of pregnant CF-1 mice, Sprague-Dawley rats and New Zealand white rabbits were exposed to 500 ppm VCM for 7 hr daily during the period of major organogenesis. Subsequently, other groups of mice were similarly exposed to 50 ppm VCM, and rats and rabbits were exposed to 2500 ppm. While maternal toxicity was observed, exposure to VCM did not cause significant embryonal or fetal toxicity and was not teratogenic in any of the three species at the concentrations tested. Simultaneous exposure of some of the pregnant animals to VCM by inhalation plus 15% ethanol in the drinking water resulted in toxic effects greater than those associated with exposure to VCM alone in the three species. The fetal effects observed were similar to those reported for these three species following administration of ethanol without VCM exposure.

Abnormalities, Drug-Induced↗
PubMed1989

Lectin histochemistry of the embryonic heart: expression of terminal and penultimate galactose residues in developing rats and chicks.

Rat embryos at days 10-18 of gestation and chicken embryos at days 3-6 of incubation were fixed and processed for lectin histochemistry. The distribution of binding sites for a lectin from the peanut Arachis hypogaea (PNA) conjugated to horseradish peroxidase (HRP) was determined on tissue sections both before and after enzymatic cleavage of sialic acid with neuraminidase (sialidase). Endocardial cushion tissue in the rat, but not in the chick, reacted with PNA-HRP prior to digestion with sialidase. Endocardium of both species (12 and 13 days in rat, 5 and 6 days in chick), particularly at the level of endocardial cushions, reacted strongly with the sialidase-PNA sequence; this staining decreased markedly after day 14 of gestation in the rat. PNA binding sites capped by sialic acid were most abundant in the developing rat heart during the critical period of endocardial cushion formation and decreased as development proceeded. The marked changes in the appearance and distribution of cardiac cell and tissue glycoconjugates during cardiogenesis support the concept that rapid changes occur in the structure of complex carbohydrates during embryonic and fetal development. The findings also suggest that such glycosylation-related events may be species specific.

Animals↗
PubMed1997

In vitro regulation of insulin release and biosynthesis of fetal rat pancreatic cells explanted on pregnancy day 16.

Although the morphological development of the fetal pancreatic B cell has been studied in considerable detail, knowledge about the functional maturation, particularly in early stages of development, is still poor. The present paper describes a method for monolayer culture of fetal rat islet cells which allows a study of the regulation of insulin biosynthesis, release and content during critical stages of embryonic and fetal development. Suspensions of pancreatic cells were prepared from rat fetuses on pregnancy day 16 and cultured for 3 days. During the initial 2 days cultures were performed in the presence of 5 or 15 mmol/l glucose. During this initial period, culture at 5 mmol/l glucose was carried out in the presence or absence of either 10 mmol/l nicotinamide (NA) or 5 or 100 ng/ml nerve growth factor (NGF). After changing the media the cells were further exposed for 24 h to either 5 or 15 mmol/l glucose or 15 mmol/l glucose plus 5 mmol/l theophylline before measuring the insulin concentration in the culture medium. Cells that had initially been cultured for 2 days in 5 mmol/l glucose showed an increased insulin release, when subsequently cultured in 15 mmol/l glucose for 24 h. Theophylline potentiated the response and caused a decrease in cellular insulin content. Cells initially cultured in the presence of 15 mmol/l glucose showed unchanged insulin release during the subsequent 24-hour exposure to 15 mmol/l glucose, irrespective of the presence or absence of theophylline. The presence of NGF (100 ng/ml) during the initial 2-day culture period increased the insulin release in the presence of 15 mmol/l glucose and theophylline during the subsequent 24-hour culture period as compared to cells cultured in the absence of NGF. When cells were first exposed to either NA or NGF followed by exposure to 5 mmol/l glucose alone in the last 24-hour culture period, there was an increased insulin content. Rates of insulin biosynthesis remained unchanged irrespective of the glucose concentration in the culture medium. It is concluded that, already in early fetal development, B cells show glucose stimulation of insulin release albeit less pronounced than in the postnatal state.

Animals↗
PubMedDate not supplied

Developmental regulation of a cloned adult beta-globin gene in transgenic mice.

At different stages of mammalian development, distinct embryonic, fetal and adult haemoglobins are synthesized in erythroid cells, a process termed haemoglobin switching. The cellular and molecular mechanisms controlling haemoglobin switching have been intensively studied, but remain poorly understood. To study the developmental regulation of globin gene expression, we have produced transgenic mice in which cloned globin genes are present in erythroid cells throughout development. Recently, we reported that adult mice in several transgenic lines carrying a hybrid mouse/human adult beta-globin gene, expressed the gene in a correct tissue-specific manner. This finding raised the question of whether an exogenous globin gene could also be subject to appropriate stage-specific regulation. We report here that the hybrid beta-globin gene, like the endogenous adult beta-globin genes, is inactive in yolk sac-derived embryonic erythroid cells and is expressed for the first time in fetal liver erythroid cells. Our results indicate that a stage-specific pattern of expression can be conferred by cis-acting regulatory elements closely linked to an adult beta-globin gene. They also suggest that the embryonic and adult beta-globin genes in the mouse are activated (or repressed) by distinct trans-acting regulatory factors present in embryonic, fetal and adult erythroid cells.

Animals↗