Effect of periconceptional nutrition on the growth, behaviour and survival of the neonatal lamb.

Periconceptional nutrition (PCN) can influence foetal hypothalamo-pituitary adrenal (HPA) axis function and alter cortisol secretion with possible consequences for maturation and growth of major organs, gestation length and behaviour. We examined effects of PCN on phenotype and survival of the neonatal lamb in 466 Merino ewes allocated to treatments providing 70%, 100% and 150% respectively, of maintenance requirements for 17 days prior and 6 days after insemination. Gestation length and birth weight for lambs in PCN treatment groups was similar (P > 0.05) but low PCN decreased the size of the neonate (crown-rump-length and metacarpal length P < 0.05). A subset of lambs euthanased at 5 days of age further showed that low PCN decreased the amount of peri-renal fat (P < 0.05) and increased liver mass (P < 0.05) while high PCN increased neck thymus and ovary mass (P < 0.05). Neonatal lambs from low PCN ewes returned faster to their mothers after release (P < 0.05) and contacted the udder in the shortest time (P < 0.05). Significant interactions between PCN treatment and sex (P < 0.05) and between PCN treatment and ewe age (P < 0.05) were also observed for time lambs took to follow the ewe. Survival of lambs was similar but potential differences may have been masked by favourable weather conditions. In conclusion, this study provides evidence of significant changes in lamb growth and development dependent on PCN and, for the first time, links these changes with significant changes in behaviour of the neonate. The impact of these effects on lamb survival and potential reproductive capacity of female offspring remains to be determined.

Maternal undernutrition around the time of conception and embryo number each impact on the abundance of key regulators of cardiac growth and metabolism in the fetal sheep heart.

Poor maternal nutrition before and during pregnancy is associated with an increased risk of cardiovascular disease in later life. To determine the impact of maternal undernutrition during the periconceptional (PCUN: -45 days to 6 days) and preimplantation (PIUN: 0-6 days) periods on cardiac growth and metabolism, we have quantified the mRNA and protein abundance of key regulators of cardiac growth and metabolism in the left ventricle of the sheep fetus in late gestation. The cardiac protein abundance of AMP-activated protein kinase (AMPK), phospho-acetyl CoA carboxykinase (ACC) and pyruvate dehydrogenase kinase-4 (PDK-4) were decreased, whereas ACC was increased in singletons in the PCUN and PIUN groups. In twins, however, cardiac ACC was decreased in the PCUN and PIUN groups, and carnitine palmitoyltransferase-1 (CPT-1) was increased in the PIUN group. In singletons, the cardiac abundance of insulin receptor ß (IRß) was decreased in the PCUN group, and phosphoinositide-dependent protein kinase-1 (PDPK-1) was decreased in the PCUN and PIUN groups. In twins, however, the cardiac abundance of IRß and phospho-Akt substrate 160kDa (pAS160) were increased in the PIUN group. The cardiac abundance of insulin-like growth factor-2 receptor (IGF-2R), protein kinase C alpha (PKCα) and mammalian target of rapamycin (mTOR) were decreased in PCUN and PIUN singletons and extracellular-signal-regulated kinase (ERK) was also decreased in the PIUN singletons. In contrast, in twins, cardiac abundance of IGF-2R and PKCα were increased in the PCUN and PIUN groups, phospho-ribosomal protein S6 (pRPS6) was increased in the PCUN group, and ERK and eukaryotic initiation factor 4E (eIF4E) were also increased in the PIUN fetuses. In conclusion, maternal undernutrition limited to around the time of conception is sufficient to alter the abundance of key factors regulating cardiac growth and metabolism and this may increase the propensity for cardiovascular diseases in later life.

Maternal undernutrition during the first week after conception results in decreased expression of glucocorticoid receptor mRNA in the absence of GR exon 17 hypermethylation in the fetal pituitary in late gestation.

Exposure to maternal undernutrition during the periconceptional period results in an earlier prepartum activation of the fetal hypothalamo-pituitary-adrenal (HPA) axis and altered stress responsiveness in the offspring. It is not known whether such changes are a consequence of exposure of the oocyte and/or the early embryo to maternal undernutrition in the periconceptional period. We have compared the effects of 'periconceptional' undernutrition (PCUN: maternal undernutrition imposed from at least 45 days before until 6 days after conception), and 'early preimplantation' undernutrition (PIUN: maternal undernutrition imposed for only 6 days after conception) on the expression of genes in the fetal anterior pituitary that regulate adrenal growth and steroidogenesis, proopiomelanorcortin (POMC), prohormone convertase 1 (PC1), 11ß-hydroxysteroid dehydrogenase type 1 and 2 (11ßHSD1 and 2) and the glucocorticoid receptor (GR) in fetal sheep at 136-138 days of gestation. Pituitary GR mRNA expression was significantly lower in the PCUN and PIUN groups in both singletons and twins compared with controls, although this suppression of GR expression was not associated with hypermethylation of the exon 17 region of the GR gene. In twin fetuses, the pituitary 11ßHSD1 mRNA expression was significantly higher in the PIUN group compared with the PCUN but not the control group. Thus, exposure of the single or twin embryo to maternal undernutrition for only 1 week after conception is sufficient to cause a suppression of the pituitary GR expression in late gestation. These changes may contribute to the increased stress responsiveness of the HPA axis in the offspring after exposure to poor nutrition during the periconceptional period.

Impact of maternal periconceptional overnutrition on fat mass and expression of adipogenic and lipogenic genes in visceral and subcutaneous fat depots in the postnatal lamb.

Women entering pregnancy with a high body weight and fat mass have babies who are at increased risk of becoming overweight or obese in later life. We investigated whether maternal overnutrition in the periconceptional period results in an increased fat mass and expression of adipogenic and lipogenic genes in offspring and whether dietary restriction can reverse these changes. Nonpregnant donor ewes (n = 23) were assigned to one of four groups: control-control fed at 100% maintenance energy requirements (MER) for at least 5 months, control-restricted fed 100% MER for 4 months and 70% MER for 1 month, high-high (HH) fed ad libitum (170-190% MER) for 5 months, or high-restricted (HR) fed ad libitum for 4 months and 70% MER for 1 month. Single embryos were transferred to nonobese recipient ewes, and lamb fat depots were weighed at 4 months. Peroxisome proliferator-activated receptor-γ, glyceraldehyde-3-phosphate dehydrogenase, lipoprotein lipase, leptin, and adiponectin mRNA expression was measured in the lamb fat depots. Total fat mass was higher in female lambs in the HH but not HR group than controls. There was a relationship between donor ewe weight and total fat mass and G3PDH mRNA expression in perirenal fat in female lambs. There was no effect of periconceptional nutritional treatment on peroxisome proliferator-activated receptor-γ, glyceraldehyde-3-phosphate dehydrogenase, lipoprotein lipase, leptin, and adiponectin mRNA expression in any fat depot. Thus, exposure to maternal overnutrition in the periconceptional period alone results in an increased body fat mass in the offspring and that a short period of dietary restriction can reverse this effect.

Periconceptional nutrition and the relationship between maternal body weight changes in the periconceptional period and feto-placental growth in the sheep.

Recent studies in the sheep have shown that maternal undernutrition during the periconceptional period, when the nutrient demands of the embryo are minimal, can alter the subsequent development of the metabolic, endocrine and cardiovascular systems and that these effects may, in part, depend on embryo number. We have tested the hypotheses that there are relationships between maternal weight or body condition at the time of conception and feto-placental growth during the first 55 days of pregnancy, and that periconceptional undernutrition has a differential effect on these relationships in singleton and twin pregnancies. We have investigated the effect of periconceptional undernutrition in the ewe (control n= 24, restricted at 70% of control feed allowance, PCUN n= 21) from 45 days prior to mating until 7 days after mating on placental and fetal weight and on placental histology in singleton and twin pregnancies at 53-56 days' gestation, i.e. during the period of maximal placental growth. In control, but not PCUN ewes carrying singleton pregnancies, there were direct relationships between maternal weight gain during the periconceptional period and uteroplacental weights at 53-56 days' gestation. There were direct relationships, however, between placental and fetal weights in both control and PCUN singleton pregnancies. In contrast to the singletons, in control twin pregnancies, there was no effect of maternal weight gain in the periconceptional period on any measure of uteroplacental growth, and there was also no relationship between placental and fetal weight. This lack of a relationship may be related to the increased uteroplacental weight and mean placentome weight in the twin pregnancies (control singletons: 2.45 +/- 0.18 g; control twins: 4.10 +/- 0.62 g). In the PCUN group, however, a greater weight loss between the start of the feeding regime and post mortem at approximately day 55, was associated with a larger placenta and fetus, and the direct relationship between placental and fetal mass was restored. In summary, the present study has demonstrated that there are important relationships between maternal weight gain during the periconceptional period and feto-placental growth during the first 56 days of pregnancy, and that periconceptional undernutrition has a differential effect on these relationships in singleton and twin pregnancies. In singleton pregnancies, periconceptional undernutrition disrupts the relationship between maternal weight gain during the periconceptional period and uteroplacental growth, and in twin pregnancies periconceptional undernutrition results in the emergence of an inverse relationship between maternal weight gain during early pregnancy and uteroplacental growth and a dependence of fetal growth on placental growth. These changes highlight the importance of the periconceptional environment in setting the placental and fetal growth trajectories, and have implications for the programmed development of the metabolic, cardiovascular and endocrine systems of the fetus and adult.

Vertebral body diameters and sex prediction.

As a direct consequence of the generally larger body size of the male, it is reasonable to expect the adult human vertebral column to display sexual dimorphism. However, there is a distinct paucity of literature concerning sex-related variation in vertebral dimensions. This study examines the accuracy with which sex may be predicted from vertebral body diameters. In a sample selected from a documental skeletal series, sex could be correctly assigned with an accuracy approaching 90%. This degree of sexual differentiation is of value for both the forensic and archeological identification of human skeletal remains. An interesting relationship was noted between the degree of expression of sexual dimorphism and the role of each area of the vertebral body in body weight transfer. The posterior aspect of the vertebral body is involved in the transmission of body weight both vertically and laterally from the transverse processes. This area was consistently less dimorphic than the anterior region of the vertebral body, which is more concerned with the transfer of body weight from the vertebra above.

The accuracy of sex identification in European skeletal remains using the phenice characters.

Three documented European skeletal series were examined to assess the accuracy and reliability of the pubic variables described by Phenice for correctly identifying the sex of adult human skeletal remains. The accuracy and objectivity of these variables, as reported by Phenice, Kelley, Sutherland and Suchey, and Lovell, could not be confirmed on this European material. In general, the subpubic concavity feature, when used alone, proved to be the most reliable variable for sex identification. In this study, the level of correct sex identification that could be achieved using the Phenice variables was shown to be significantly affected by the previous experience of the observer.

The sciatic notch/acetabular index as a discriminator of sex in European skeletal remains.

The sciatic notch/acetabular index and its rule of thumb application was tested on two European skeletal series of documented sex. The results showed poor consistency between documented and estimated sex. Of the two variables comprising the index, it appeared that sciatic notch width was a particularly poor discriminator of sex. It is suggested that this may be due to differences in the relationship between sciatic notch form and body size in different ethnic groups.

A simple univariate technique for determining sex from fragmentary femora: its application to a Scottish short cist population.

A simple univariate technique for sexing individuals represented by fragmentary skeletal remains is described. The results obtained were highly consistent (about 90%) with those obtained by conventional analysis of pelvic and cranial morphology. It is suggested that using maximum anteroposterior diameter of the femoral shaft as a sex discriminator has advantages over midshaft circumference even when intact femora are available.

Epidural anesthesia for obstetric patients.

The use of epidural anesthesia for the obstetric patient is increasing in many areas of the country. The maternity nurse needs to have a basic understanding of the technique used by the physician to initiate this type of anesthesia, and also has a responsibility to know the contraindications, possible complications, and disadvantages and advantages of epidural anesthesia. This information is presented below. Skilled nursing and medical management will reduce the potential risks of epidural anesthesia for both the mother and fetus.