Objectives: To determine the levels of tocopherols, retinol and carotenoids in maternal and umbilical cord blood plasma and to investigate the relationships between them. Design: Venous blood plasma concentrations of a, g and d-tocopherol, retinol, lutein, lycopene, zeaxanthin, bcryptoxanthin, a and b-carotene were determined by HPLC in healthy pregnant women and in pair-matched umbilical cords. Plasma levels of triglycerides and cholesterol were also measured. Subjects: Sixty-six women, between 10 and 20 weeks gestation, were recruited randomly during their ®rst antenatal appointment. From this group, 40 pair-matched umbilical cord blood samples were obtained. Results: Tocopherols, retinol, carotenoids and lipids were present in signi®cantly higher (P`0.001) concentrations in maternal plasma than in cord plasma. There was a signi®cant correlation (r 0.45, P`0.005) between maternal and cord levels of g-tocopherol, but not of a-tocopherol, retinol or carotenoids. Tocopherols and carotenoids were signi®cantly correlated with each other (P`0.05) in maternal and cord plasma. Cconclusions: Plasma levels of tocopherols, carotenoids and lipids are substantially lower at birth than in adulthood. There is a clear relationship between g-tocopherol levels in maternal and cord plasma. The importance of g-tocopherol in human nutrition should be further investigated. There are no signi®cant relationships between plasma a-tocopherol and carotenoids in pregnant mothers and cords. More research is needed to elucidate the maternal-foetal transfer of tocopherols and carotenoids, and to examine the impact of maternal antioxidant nutrient status on neonatal antioxidant capacity. It is important to determine if a low level of tocopherols and carotenoids at birth is a normal stage of human development or indicative of de®ciency.

Leptin, a recently discovered hormone secreted mainly from adipose tissue, was first described as a regulator of adiposity, food intake and energy metabolism. It is now apparent that leptin physiology is much more complex and is likely to play an important role in many other systems including reproduction, haematopoiesis and immunity. Leptin levels have been shown to be well correlated with body fat in both humans and rodents, with administration of exogenous leptin to rats and mice resulting in loss of body fat. Leptin is, therefore, likely to be an important humoral signal to the central nervous system on body composition and regulation of food consumption.Due to the limited cross-reactivity of leptin from other species in the current assays for leptin, physiological research on leptin has, to a large extent, been restricted to rodents and humans. The aim of this study was to develop a leptin immunoassay suitable for use with sheep, enabling the investigation of the basic physiology of leptin in an animal larger than rats or mice, thus allowing repeated blood sampling. Using this assay we investigated the short-term effects of insulin, adrenaline and glucagon (all modulators of blood glucose) on plasma leptin levels.Antiserum to bovine recombinant leptin (brLeptin) raised in chickens was used to develop a competitive ELISA. Using brLeptin as standard, the assay has a sensitivity of 0·5 ng/ml with inter-and intra-assay variation of 15% and 7% respectively. The cross-reactivity of human recombinant leptin was 36·5%, while mouse leptin showed no cross-reactivity. Plasma samples from ewes, male castrate animals and rams (n=4-5) diluted in parallel to the standard with mean leptin concentrations of 6·0 2·9, 3·3 0·4 and 3·1 1·3 ng/ml respectively. Leptin levels in rams were significantly lower than in ewes. The non-significant difference in leptin levels between rams and male castrate animals suggests that testosterone may not be responsible for the lower levels of leptin.Four groups of 3-4 ewes were given intravenous insulin (1 iu/kg), adrenaline (65 µg/kg), glucagon (24 iu/kg) or saline. Blood samples were taken at 1, 3, 5, 10, 20, 30, 60, 90 and 120 min after injection. As expected, glucose levels declined within 10 min of the insulin injection and rose after 3 min following both adrenaline and glucagon injections. Leptin levels, however, remained relatively unchanged for the 2 h following the treatments. Finally, a bolus intravenous dose of glucose (240 mg/kg) was given and sequential blood samples taken. Despite plasma glucose levels rising to over 200 mg/dl, leptin levels did not significantly change over the three hours following treatment. These data indicate that plasma leptin levels in sheep, in contrast to rodents, are not responsive to short-term changes in blood glucose or insulin, as has been shown in humans.

No abstract

Adult hypertension has been linked to fetal growth. This study investigates whether this link is evident in the newborn. We measured blood pressure by oscillometry in 248 healthy neonates on day 3/4 of life. Antenatal data and neonatal measurements were obtained from hospital records. Elevated neonatal blood pressure correlated with higher birthweight. There was no correlation between placental weight and blood pressure. Babies born by caesarean section had lower systolic blood pressure. Babies of maternal smokers had higher diastolic blood pressure, but their mothers (45% of this study) had lower blood pressure than non-smokers. Thus, smoking was associated with a significant change in both maternal and neonatal blood pressure, and may be an important influence on the developing cardiovascular system.

Objective: To determine the concentrations of the low molecular weight antioxidants urate, bilirubin, albumin and sulphydryl groups and to measure lipid peroxidation levels in pair-matched maternal and cord blood plasma. Design: Venous blood plasma concentrations of urate, bilirubin, albumin and sulphydryls were determined in healthy pregnant women and in pair matched umbilical cords. The ability of maternal and cord plasma to withstand Cu 2 -induced lipid peroxidation was assessed by measuring the production of thiobarbituric acid reactive substances (TBARS) over time in plasma incubated with Cu 2 . Subjects: Forty healthy women, between 10 and 20 weeks gestation, were recruited randomly from an antenatal clinic. Venous blood samples were obtained from the mothers at the recruitment stage and from the umbilical cords of their newborn after delivery. Results: Urate, bilirubin and sulphydryls were present in signi®cantly higher concentrations (P`0.001) in cord plasma than in maternal plasma. Albumin levels were similar in mothers and cords. Signi®cantly lower levels (P 0.018) of TBARS were produced in cord plasma compared with maternal plasma following incubation with Cu 2 . There were signi®cant correlations between albumin and sulphydryl concentrations in maternal plasma (r 0.43, P 0.007) and between urate concentrations in maternal and cord plasma (r 0.37, P 0.026). Conclusion: Urate, bilirubin and sulphydryls are present in signi®cantly higher concentrations in cord blood than in maternal blood. The increased levels of these antioxidants in cord plasma may contribute to the increased resistance of cord plasma to Cu 2 -induced lipid peroxidation.

Serum methotrexate levels were measured for 5 h after oral intake in 11 children with acute lymphoblastic leukaemia. The curves obtained with the child's regular dose of methotrexate varied widely, and were independent of the doses used. Peak levels were found in samples taken up to 3h after ingestion, and ranged from 300 to 1250 ng/ml. In the doses used, methotrexate toxicity was present in one of the eleven children, and was associated with a delayed peak and a high 5-h methotrexate level. Individual drug metabolism could be an important factor in the response to treatment, and needs to be evaluated in the assessment of protocols.

The concentrations of tocopherols and carotenoids are lowered in umbilical cord blood plasma, which may have a negative effect on antioxidant protection in neonates. Smoking may adversely affect dietary intakes and plasma concentrations of carotenoids. The dietary intakes of vitamin E and beta-carotene were assessed in 66 pregnant women (31 smokers and 35 non-smokers) between 10 and 20 weeks gestation using a food frequency questionnaire. The concentrations of alpha-tocopherol and beta-carotene were measured in maternal plasma at the time of the dietary assessment, and in the matched umbilical cords of their newborn after delivery. In smoking and non-smoking mothers, the mean intakes of vitamin E (9.3 [SD 5] and 8.2 [SD 5] mgd-1) and beta-carotene (3464 [SD 1885] and 2977 [SD 1503] micrograms d-1) were not significantly different. The plasma concentrations of alpha-tocopherol (20.8 [SD 4] and 20.5 [SD 4] mumol L-1), the alpha-tocopherol to lipid ratios (3.2 [SD 0.8] and 3.5 [SD 0.8]) and the plasma concentrations of beta-carotene (0.22 [SD 0.1] and 0.22 [SD 0.1] mumol L-1) were not significantly different in smoking and non-smoking mothers. There were no significant differences in plasma alpha-tocopherol (7.4 [SD 2] and 7.3 [SD 2] mumol L-1), in alpha-tocopherol to lipid ratios (3.2 [SD 0.6] and 2.8 [SD 0.6]) or in beta-carotene concentrations (0.05 [SD 0.04] and 0.03 [SD 0.02] mumol L-1) in cords from newborns of smoking and non-smoking mothers. There was a significant correlation (r = 0.41, P = 0.015) between dietary intakes and plasma concentrations of beta-carotene in non-smoking mothers. However, this relationship was not significant in smoking mothers (r = 0.28, P = 0.12). There were no relationships between dietary intakes and plasma concentrations of tocopherol. These results indicate that smoking during pregnancy does not appear to affect the dietary intakes or plasma concentrations of alpha-tocopherol and beta-carotene in pregnant women or their babies. However, smoking does influence the relationship between dietary intakes and plasma levels of beta-carotene.

Growth and hypothalamic-pituitary function have been studied in children in long-term remission from acute lymphoblastic leukaemia (ALL). All 14 children are growing and developing normally; in the 8 children in whom the hypothalamic pituitary axis was investigated endocrine function is normal. Continuing long-term review of these children is essential, but hypothalamic-pituitary investigation is required only when there is a decrease in growth velocity or delay in the onset of puberty.