(1/1684) Restriction of placental and fetal growth in sheep alters fetal blood pressure responses to angiotensin II and captopril.
1. We have measured arterial blood pressure between 115 and 145 days gestation in normally grown fetal sheep (control group; n = 16) and in fetal sheep in which growth was restricted by experimental restriction of placental growth and development (PR group; n = 13). There was no significant difference in the mean gestational arterial blood pressure between the PR (42.7 +/- 2.6 mmHg) and control groups (37.7 +/- 2.3 mmHg). Mean arterial blood pressure and arterial PO2 were significantly correlated in control animals (r = 0.53, P < 0.05, n = 16), but not in the PR group. 2. There were no changes in mean arterial blood pressure in either the PR or control groups in response to captopril (7.5 microg captopril min-1; PR group n = 7, control group n = 6) between 115 and 125 days gestation. After 135 days gestation, there was a significant decrease (P < 0.05) in the fetal arterial blood pressure in the PR group but not in the control group during the captopril infusion (15 microg captopril min-1; PR group n = 7, control group n = 6). 3. There was a significant effect (F = 14.75; P < 0.001) of increasing doses of angiotensin II on fetal diastolic blood pressure in the PR and control groups. The effects of angiotensin II were different (F = 8.67; P < 0.05) in the PR and control groups at both gestational age ranges. 4. These data indicate that arterial blood pressure may be maintained by different mechanisms in growth restricted fetuses and normally grown counterparts and suggests a role for the fetal renin-angiotensin system in the maintenance of blood pressure in growth restricted fetuses. (+info)
(2/1684) Changes in surfactant-associated protein mRNA profile in growth-restricted fetal sheep.
To test the hypothesis that chronic placental insufficiency resulting in fetal growth restriction causes an increase in fetal lung surfactant-associated protein (SP) gene expression, we embolized chronically catheterized fetal sheep (n = 6) daily using nonradioactive microspheres in the abdominal aorta for 21 days (between 0.74 and 0.88 of gestation) until fetal arterial oxygen content was reduced by approximately 40-50%. Control animals (n = 7) received saline only. Basal fetal plasma cortisol concentration was monitored. At the end of the experiment, fetal lung tissues were collected, and ratios of tissue levels of SP-A, SP-B, and SP-C mRNA to 18S rRNA were determined by standard Northern blot analysis. Total DNA content of fetal lungs was reduced by 30% in the embolized group compared with control group (P = 0.01). There was a 2.7-fold increase in fetal lung SP-A mRNA (P < 0.05) and a 3.2-fold increase in SP-B mRNA (P < 0.01) in the chronically embolized group compared with those in the control group. SP-A and SP-B mRNA tissue levels were highly correlated with the mean fetal plasma cortisol levels on days 20-21 (r = 0.90, P < 0.01 for SP-A mRNA and r = 0.94, P < 0.01 for SP-B mRNA). SP-C mRNA tissue levels were not significantly affected by placental insufficiency. We conclude that fetal growth restriction due to placental insufficiency is associated with alterations in fetal lung SP, suggesting enhanced lung maturation that was highly dependent on the degree of increase in fetal plasma cortisol levels. (+info)
(3/1684) Endothelial function is impaired in fit young adults of low birth weight.
OBJECTIVE: Non-insulin-dependent diabetes, hypertension and ischaemic heart disease, with insulin resistance, are associated with low birth weight (the 'Small Baby Syndrome'). Common to these adult clinical conditions is endothelial dysfunction. We tested the hypothesis that endothelial dysfunction could precede their development in those of low birth weight. METHODS: Endothelial function was measured by ultrasonic 'wall-tracking' of flow-related brachial artery dilatation in fit 19-20 year old subjects randomly selected (blind to the investigators throughout the study) from low (< 2.5 kg) and normal (3.0-3.8 kg) birth weight subjects in the 1975-7 cohort of the Cardiff Births Survey and with no known cause for endothelial dysfunction. RESULTS: Flow-related dilatation was impaired in low birth weight relative to normal birth weight subjects (median 0.04 mm [1.5%] [n = 22] cf. 0.11 mm [4.1%] [n = 17], p < 0.05; 0.04 mm [1.5%] [n = 15] cf. 0.12 mm [4.4%] [n = 12], p < 0.05 after exclusion of inadvertently included ever-smokers). CONCLUSION: The findings suggest that endothelial dysfunction is a consequence of foetal malnutrition, consistent with contributing to the clinical features of the 'Small Baby Syndrome' in later adult life. (+info)
(4/1684) Fetal yawning activity in normal and high-risk fetuses: a preliminary observation.
OBJECTIVE: To study yawning activity in healthy fetuses and in fetuses at high risk. METHODS: Yawning activity was studied in 16 healthy and 22 high-risk fetuses. Studies were performed in the postprandial state at 09.00 and 12.00 in a quiet room with the woman in the lateral recumbent position. All ultrasound examinations were performed using a 3.5-MHz Acuson 128 PX curvilinear probe. Fetal lips, mouth, tongue, pharynx, larynx, trachea and esophagus were surveyed in serial coronal and sagittal planes. All fetal mouthing movements were analyzed by a review of the videotape in slow motion. RESULTS: In both normal and high-risk fetuses, yawning was represented by isolated mouthing movements and consisted of slow opening of the mouth with simultaneous downward movements of the tongue. This phase occupied 50-75% of the yawning cycle. After reaching its maximum opening, the mouth remained wide open for 2-8 s and returned to its resting position within seconds. Growth-restricted fetuses demonstrated yawning patterns consisting of isolated yawns similar to those seen in healthy fetuses. Unusual bursts of fetal yawning activity were recorded in anemic fetuses. CONCLUSION: Yawning activity in anemic fetuses may represent a compensatory process to increase venous return to the heart. (+info)
(5/1684) The effects on fetal development of high alpha-fetoprotein and maternal smoking.
OBJECTIVES: This study determined the risk of impaired fetal growth resulting from the interaction between maternal smoking during pregnancy and unexplained elevated concentrations of maternal serum alpha-fetoprotein (MSAFP). METHODS: This observational study involved 123 pregnant smokers with unexplained second-trimester elevated concentrations of MSAFP, 827 smokers with normal levels, and 471 nonsmokers with raised levels. RESULTS: By logistic regression, coincident smoking and elevated MSAFP levels were found to be associated with increases in the low basic risks of prematurity, small-for-gestational-age births, low birthweight, and need for neonatal care. CONCLUSIONS: Maternal smoking has an adverse effect on fetal development in pregnancies with unexplained elevated MSAFP concentrations. Such pregnancies merit close surveillance. (+info)
(6/1684) Characteristics of blood flow in intrauterine growth-restricted fetuses with hypercoiled cord.
OBJECTIVE: To clarify the characteristics of fetoplacental blood flow of growth-restricted fetuses with hypercoiled umbilical cord. SUBJECTS: Eight growth-restricted fetuses with hypercoiled cord. METHODS: Flow velocity waveforms of the umbilical cord artery and vein, fetal abdominal aorta and fetal inferior vena cava were analyzed. RESULTS: The resistance index in the umbilical artery in the hypercoiled cases was lower than that in normal fetuses. Early-diastolic reversed flow was observed in the abdominal aorta in some cases. In all cases, umbilical venous pulsation was observed in the entire cord until delivery. In one case, fetal heart failure occurred, resulting in pre-mature delivery. An atrophic type of single umbilical artery was observed in four cases. CONCLUSION: Fetal blood flow disturbance caused by a hypercoiled umbilical cord may be a cause of growth restriction. (+info)
(7/1684) Chemical hair treatments and adverse pregnancy outcome among Black women in central North Carolina.
Several studies suggest that toxic chemicals in hair products may be absorbed through the scalp in sufficient amounts to increase the risks of adverse health effects in women or their infants. This case-control study of 525 Black women from three counties in North Carolina who had delivered a singleton, liveborn infant examined whether exposure to chemicals used in hair straightening and curling increased the odds that the infant was preterm or low birth weight. Cases consisted of 188 preterm and 156 low birth weight births (for 123 women, their infant was both low birth weight and preterm). Controls were 304 women who delivered term and normal birth weight infants. Women who used a chemical hair straightener at any time during pregnancy or within 3 months prior to conception had an adjusted odds ratios (OR) of 0.7 (95% confidence interval (CI) 0.4-1.1) for preterm birth and 0.6 (95% CI 0.4-1.1) for low birth weight. Exposure to chemical curl products was also not associated with preterm delivery (adjusted OR = 0.9, 95% CI 0.5-1.8) or low birth weight (adjusted OR = 1.0, 95% CI 0.5-1.9). Despite this failure to find an association, continued search for risk factors to which Black women are uniquely exposed is warranted. (+info)
(8/1684) Growth retardation of inner cell mass cells in polyspermic porcine embryos produced in vitro.
The in vitro viability of polyspermic pig eggs was investigated. Immature oocytes were matured and fertilized in vitro. Approximately 10 h after insemination, the eggs were centrifuged at 12 000 x g for 10 min and individually classified into two (2PN)- and poly-pronuclear (PPN, 3 or 4 pronuclei) eggs. The classified eggs were cultured in vitro or in vivo. Nuclei numbers of inner cell mass (ICM) and trophectoderm (TE) were compared between 2PN- and PPN-derived blastocysts. The frequency of development in vitro of 2PN and PPN eggs to the blastocyst stage was 53.6% and 40.7%, respectively. The mean number (8.2 +/- 0.7, n = 48) of ICM nuclei of 2PN-derived blastocysts was higher than that (4.2 +/- 0.8, n = 37) of PPN-derived blastocysts (p < 0.001), whereas there was no difference (p > 0.05) in mean numbers of total (46.7 +/- 3.4 vs. 39. 9 +/- 3.9) and TE nuclei (38.5 +/- 2.9 vs. 35.7 +/- 3.3) between the two groups. Development of 2PN and PPN eggs cultured in vivo to the blastocyst stage was 33.3% and 27.4%, respectively. The numbers of ICM and TE nuclei of these embryos cultured in vivo showed a pattern similar to that for the in vitro-produced blastocysts. Additionally, fetuses were obtained on Day 21 from both the 2PN and the PPN groups. This suggests that polyspermic pig embryos develop to the blastocyst stage and beyond, although showing a smaller ICM cell number as compared to normal embryos. (+info)