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At least 469 records · Page 26Linked to original sources
PubMed1994

Inhibition of iodothyronine 5'-deiodinase by iopanoic acid does not block nuclear T3 accumulation during rat fetal development.

We studied the effect of iopanoic acid (IOP), an iodinated contrast medium, on iodothyronine 5'-deiodinase (5'D) and nuclear T3 content (nT3) in fetal tissues. In 18- and 20 day-old fetuses from control dams, nT3 was higher in interscapular brown adipose tissue (IBAT, 69 +/- 5 and 281 +/- 8 fmol/mg of DNA) than in brain (16 +/- 2 and 42 +/- 3 fmol/mg of DNA) or liver (5.6 +/- 1 and 27 +/- 2 fmol/mg of DNA). IOP administration (10 mg, twice daily) to pregnant rats on days 18 and 19 postconception significantly blocked 5'D activity in fetal IBAT and brain at day 20. Liver 5'D was not affected. The rise in nT3 was not modified by IOP treatment in IBAT, but it was enhanced in brain and liver of IOP-treated fetuses on day 20. In contrast, in adult rats, IOP treatment reduced IBAT nT3. Prolongation of IOP treatment until day 21 decreased fetal body weight on day 22 and inhibited IBAT 5'D. No change was produced in mitochondrial oxidative capacity, the subunit II of cytochrome oxidase, or uncoupling protein mRNA expression in IBAT from IOP-treated fetuses. Thus, the finding that IOP does not decrease the nT3 of fetal IBAT explains the lack of effect of IOP on uncoupling protein expression in fetuses, in contrast with the known decrease in adults. Present results also show that IOP increases nT3 in brain and liver, indicating a general incapacity of IOP to decrease nT3 in fetal tissues. It is concluded that the effects of IOP during fetal life differ from those in adults.

Adipose Tissue, Brown↗
PubMed1994

Oral polio vaccination during pregnancy: lack of impact on fetal development and perinatal outcome.

Prompted by a nascent epidemic of poliomyelitis in Finland, a mass vaccination program with live oral poliovirus vaccine (OPV) was implemented in February and March 1985. The final rate of coverage was approximately 94%. Pregnant women were included, and a cohort study was launched to evaluate any harmful effects of OPV on the developing embryo. All records of births to mothers who were pregnant during the period of vaccination and whose infants were delivered at the three major hospitals in the Helsinki area were reviewed. Within the study cohort, mothers were grouped into three categories according to their trimester of pregnancy during the program. In addition, two reference cohorts were evaluated; these cohorts consisted of infants delivered at the same hospitals during the second half of 1984 and of 1986, respectively. Each of the three categories in the study cohort included approximately 3,000 children, while each reference cohort included approximately 6,000 children. Data were analyzed on the rate of intrauterine growth and the prevalences of stillbirth, neonatal death, congenital malformation, premature birth, perinatal infection, and neurological aberration. No differences were documented among the study and reference cohorts or among the three categories within the study cohort. Thus, under the conditions described here, the inclusion of pregnant women in programs of mass vaccination with OPV appears to be safe.

Cohort Studies↗
PubMed1993

Intracellular signalling of epinephrine in rat hepatocytes during fetal development and hepatic regeneration.

The changes in intracellular calcium concentration and IP3 production after the addition of epinephrine were analysed in adult, fetal (20th-22nd day of intrauterine life), and regenerating rat hepatocytes (4 h-24 h after partial hepatectomy) to determine whether the signal transduction is the same in quiescent proliferating and differentiating cells. The epinephrine treatment causes a significative cytosolic calcium transient in hepatocytes isolated in the last day of fetal life (22-day old) and in the early stage of regeneration (4 h). This effect is not significant in the previous stage of fetal life (20-day old) and at the onset of M phase of cell cycle after partial hepatectomy (24 h). [3H]myo inositol incorporation into IP3 and IP4 is higher in 20 day fetal and regenerating hepatocytes with respect to the control. In these cells the epinephrine does not affect basal level of IP3 and IP4, while it causes a substantial increase of these inositol phosphates in adult hepatocytes. [3H]myo inositol incorporation into PIP2 is very low at the 20th day of fetal life. Epinephrine has no effect on this parameter in fetal and regenerating hepatocytes. Our results show that the epinephrine signal is mediated differently in proliferating and in quiescent hepatocytes.

Animals↗
PubMed1999

The influence of maternal nutrient restriction in early to mid-pregnancy on placental and fetal development in sheep.

Placental weight is a primary factor determining size at birth in many species. In sheep, placental weight peaks at approximately mid-gestation, with structural remodelling occurring over the second half of pregnancy to meet the increasing nutritional demands of the growing fetus. Numerous factors influence placental growth and development in sheep, and many workers (see Kelly, 1992) have investigated the role of maternal nutrition as a regulator of placental and fetal size. We have studied the effects of feeding ewes approximately 50% of their recommended energy requirements during early to mid-pregnancy on fetal and placental indices measured at mid-gestation (i.e. 80 d) and close to term (i.e. 145 d). Maternal nutrient restriction is associated with a reduction in placental weight at 80 d, but an increase in placental weight at 145 d of gestation, compared with ewes fed adequately in early pregnancy. No significant effect on fetal weight was observed at either 80 or 145 d gestation, although differences in body dimensions and the insulin-like growth factor-1 axis were found in lambs from nutrient-restricted ewes delivered close to term. Maternal nutrition during pregnancy plays a pivotal role in the regulation of fetal and placental development in sheep, and therefore has the potential to influence both short- and longer-term health outcomes.

Animals↗
PubMed1977

Endocrine regulation of fetal development and its relation to parturition in the rhesus monkey.

Rhesus monkey fetuses were surgically prosencephalectomized (Type 2) or functionally hypophysectomized (Type 1) at 75 days gestation, then returned to the uterus until elective Caesarean section on day 145--150 (term 167 days). Deprivation of fetal hypothalamic releasing factors in Type 2 and fetal pituitary tropic hormones in Type 1 significantly delayed the ontogeny and functional development of fetal endocrine tissues. Bone ossification and growth were significantly retarded in Type 1 only, not in Type 2. In Type 1 the body and all organs except the endocrine glands were about half normal weight. The adrenals, thyroids, ovaries and testes were histologically abnormal and about one-tenth normal weight. Non-endocrine organs were histologically similar to 110-130-day fetuses. Thyroxine (T4) concentrations were significantly depressed in Type 1 fetal and maternal plasma at Caesarean section but normal in Type 2. Cortisol concentrations were normal in Type 1 fetal and maternal plasma. Types 1 and 2 plasma oestradiol concentrations were significantly lower in mothers but normal in fetuses. Type 1 placentas produced significantly less progesterone in vitro than normal. Fetal endocrine autonomy is indicated (thyrotropin-releasing factor excepted). Many of the hypothalamic and anterior pituitary hormones do not pass in effective amounts from mother to fetus. Fetal endocrine autonomy is a prerequisite for the control of both development and parturition.

Adrenal Glands↗
PubMed1992

Some effects of feeding Tribulus terrestris, Ipomoea lonchophylla and the seed of Abelmoschus ficulneus on fetal development and the outcome of pregnancy in sheep.

Pregnant ewes and their fetuses were chronically catheterized using aseptic procedures under general anaesthesia, and the ewes were then fed either lucerne chaff alone, or lucerne mixed with dried plant material obtained from one of three forb species, Tribulus terrestris (caltrop), Abelmoschus ficulneus (native rosella) or Ipomoea lonchophylla (cowvine), from 103-112 days gestation until term. Ingestion of the forb material was not associated with changes in maternal blood gases, plasma glucose concentrations, or the length of gestation. However, ingestion of rosella seed was associated with a significantly greater fall of fetal arterial pO2 with advancing gestation, and ingestion of either rosella or cowvine was associated with significantly lower fetal mean arterial pressure at 127-131 days, compared with the Tribulus and lucerne groups. Also, the incidence of fetal breathing movements was significantly lower, and did not show a normal day-night variation, in each of the forb-fed groups compared with the lucerne-fed group. The results indicate that these forb plants may contain substances that affect the functional development of the fetal brain. Although ingestion of these plants did not appear to affect the outcome of pregnancy in this study, the possibility that these forbs have a greater impact in sheep populations with poor nutrition and in more extreme environmental conditions is discussed.

Animal Feed↗
PubMed2006

Embryo-fetal development toxicity of prenatal exposure to penequine hydrochloride intramuscularly in rats.

The potential for penequine hydrochloride to induce maternal and embryo-fetal developmental toxicity was evaluated in Wistar rats. The drug was administered intramuscularly (i.m.) at dose levels of 0, 10, 30 or 50mg/kg/day to groups of pregnant rats from day 6 to 15 of gestation. All dams were observed for maternal body weights, food consumption and any abnormal change, and subjected to caesarean-section on gestation day (GD) 20; all fetuses obtained from caesarean-section were assessed by external inspection, visceral and skeletal examinations. In the 50mg/kg/day group, maternal toxicity included an increase in the incidence of abnormal clinical signs, and decrease in the body weight and body weight gain. Developmental toxicity included an increase in the postimplantation loss, a decrease in the litter size, and a reduction in the gravid uterus weight. In addition, a statistically non-significant increase in the incidence of fetal external, visceral, and skeletal alterations including malformations and variations were seen in high-dose group. There were no treatment-related findings in maternal clinical and intrauterine observations, and fetal morphological examinations in mid-, low-dose and control groups. Thus, under the conditions of this study, the no-observed-adverse-effect-level (NOAEL) and lowest-observed-adverse-effect-level (LOAEL) of penequine hydrochloride for both maternal and embryo-fetal toxicity in the Wistar rats were considered to be 30mg/kg/day and 50mg/kg/day, which are approximately 900 and 1500 above the therapeutic dosage, respectively.

Abnormalities, Drug-Induced↗
PubMed1993

Expression of human cytochrome c oxidase subunits during fetal development.

Expression of human cytochrome c oxidase (COX) subunits was examined at fetal (20-28 weeks) and adult state by Northern blot hybridization with mRNA from liver, heart, skeletal muscle, and intestine. The data were related to COX and citrate synthase activities and to immunodetected COX subunits (II/III, IV, VIIaH). In liver little changes of COX transcripts are observed from fetal to adult state. In contrast, in heart and skeletal muscle all transcripts of COX subunits increase between 2-20-fold, when related to the amount of 28S rRNA. In fetal heart and skeletal muscle the relative amounts of the liver-type transcripts of subunit VIa were 30% and 25% from total VIa transcripts (VIaL+VIaH), respectively, but decrease to only 2-5% at adult state. The liver-type transcripts of subunit VIIa occur to 50% in fetal heart and skeletal muscle, which remained unchanged in adult heart and decrease to 5-8% in adult skeletal muscle. The results clearly indicate a switch of gene expression in heart and skeletal muscle during development, from the liver type to the heart/muscle type of subunit VIa (and partly VIIa).

Adult↗
PubMed2005

[Effect of maternal diabetes on human and rat fetal development].

Diabetes is a genetically determined metabolic disease with fasting hyperglycemia due to relative or absolute absence of insulin. With the use of exogenous insulin, successful gestations are now possible. Nevertheless, there are still severe problems associated, such as spontaneous abortion, perinatal mortality and congenital malformations. Caudal regression syndrome, disclosure of the neural tube and cardiovascular alterations are the most common malformations. Gestational diabetes can induce increased fetal corporal fat and macrosomia with hyperinsulinemia, hypoglycemic, hypoxia, metabolic acidosis and perinatal death. During adult life, diabetic mothers' children can develop obesity, glucose intolerance and type 2 diabetes. In order to study fetuses' alterations during diabetic gestations we now have animal models of diabetes. Maternal diabetes in rats alters fetal development in a very similar manner to that of humans. Although we do not accurately know the pathogenic mechanism by which diabetes produces fetuses' abnormal development, hyperglycemia and hyperketonemia had been mentioned to have predominant roles. Hyperglycemia damages DNA and increases oxidative stress and hyperketonemia increases the rate of embryo malformations. The addition of antioxidants such as C and E vitamins can reduce this damage. During adult life, diabetic rats' cubs have alterations in glucose metabolism and in reproductive function. The understanding of mechanisms by which maternal diabetes affects fetuses development, can help us to prevent complications and improve mothers' and children's life quality.

Adult↗