The Ca and P intakes of 148 pregnant and lactating women in a rural village in The Gambia, West Africa, have been estimated by direct weighing of food on a total of 4188 d. The Ca and P contents of local foods were determined by analysis of raw ingredients, snack foods and prepared dishes. Information about the contribution of mineral-rich seasonings was obtained. Efforts were made to discover unusual sources of Ca that might not be perceived as food by subject or observer. The main contributors to daily Ca intake were shown to be leaves, fish, cereals, groundnuts and local salt. Cow's milk accounted for only 5 ' YO of Ca intake. Unusual sources of Ca were discovered, namely baobab (Adunsonia digitata) fruit and selected earths, but these were consumed infrequently and their contributions to Ca intakes were small. Cereals and groundnuts were the main sources of P. Ca and P intakes (mg/d) were shown to average 404 (SD 110) and 887 (SD 219) respectively. Seasonal changes in the availability of leaves, cereals and groundnuts resulted in variations in Ca and P intakes. The rainy season was associated with increased Ca intakes (by 16%) but decreased P consumption (by 15%). No difference was observed in Ca intake between pregnant and lactating women but P intake in lactation was 11 YO higher than that in pregnancy during the post-harvest season. The implications of these low Ca intakes require investigation.
SummaryNitrogen metabolism was studied in three preterm infants (mean gestation 32 wk) by the method of consecutive metabolic balance. The absorption and retention of nitrogen from breast milk was measured, and protein turnover, synthesis, and breakdown were calculated from isotopic plateau of urinary urea and ammonia using an intermittent oral administration of "N-glycine. Weight gain and nitrogen retention were compared with the weight gain and nitrogen accumulated for a foetus of equivalent gestational age in utero.The average composition of the milk was 289 + 19 K J dl-' and 1.44 + 24 g protein dl-'. The intake of energy was 572 + 61 KJ kg-' day -' and of nitrogen 447 + 99 mg kg-' day-'. Stool output of nitrogen was 100 + 32 mg kg-' day-' giving an absorption of 348 + 78 mg kg-' day-', as urinary excretion was 91 + 17 mg kg-' day-' retained nitrogen was 256 2 71 mg kg-' day-', or 56% of intake.The specific weight gain was 15.6 5 2.6 g kg-' day-' and 53% of this comprised lean tissue (range 34 to 89%). In all but one study the postnatal retention of nitrogen fell far short of calculated in utero accumulation.The results of protein turnover were surprising. In six of the eight studies urinary urea failed to become enriched at all. Protein turnover calculated from the ammonia plateau was 1.94
Detailed investigation of breast-milk calcium concentrations during 2 years of lactation have been conducted in Cambridge, UK, and rural Gambia. Mature milk concentrations remained steady for 3 months but declined during months 4-12 by over 25% (p less than 0.001). The pattern was identical in both communities despite differences in breast-feeding practices. Calcium concentrations were not related to feed frequency or breast-milk sodium concentrations, suggesting that breast involution is not responsible for the decrease after 3 months. Breast-milk calcium concentrations were characteristic of the individual, varied twofold between mothers and were independent of maternal age, parity and milk output. Gambian breast-milk contained 19% less calcium than Cambridge milk, throughout lactation (p less than 0.001). The extent to which this reflected the lower calcium intakes of Gambian mothers is unknown. Further studies are required to determine factors regulating breast-milk calcium secretion.
1. Rabbits in balance on a low sodium diet were given doses of sodium chloride either orally or intravenously. 2. Those receiving oral doses responded with a much greater natriuresis than those receiving intravenous ones. 3. This could be explained by the existence of a sodium input monitor somewhere in the gut or portal circulation.
Over five weeks 136 out of 246 deliveries were studied. Maternal plasma sodium concentrations were normal at admission. At delivery no significant difference was found between maternal and infant cord plasma sodium concentrations. Twenty-four of the 41 mothers who had received only oral fluids during labour had infants whose cord plasma sodium concentrations were normal. Of the 95 mothers who had been given intravenous fluids, however, only 14 had infants with normal plasma sodium concentrations, 31 had a concentration of 130 mmol (mEq)/l or less and nine of these had a concentration of 125 mmol/l or less. There was a highly significant inverse relation between cord plasma sodium concentration and rate of fluid administration, suggesting that hyponatraemia was due to intravenous treatment with predominantly sodium-free solutions. Endogenous antidiuretic activity probably increases during labour, and synthetic oxytocin in large doses has been shown to have an antidiuretic effect. The dose used in this study did not appear to have such an effect. Glucose solutions are often used as a vehicle for oxytocin; 83% of all fluid intake in this study was 5% or 10% glucose in water.Fluid balance in labour should be supervised closely, and oxytocin should be given in a more concentrated solution.
SUMMARY Continuous sequential urinary arginine vasopressin measurements in 14 preterm, ventilated infants suggest that both osmoreceptor and volume receptor systems are able to stimulate the prolonged secretion of arginine vasopressin from 26 weeks' gestation. The kidney is able to respond to arginine vasopressin stimulation from the first day of life and from 26 weeks' gestation. A maximum urine osmolality not exceeding 550 mOsm/kg was reached which varied with hydration of the infant. Excretion of arginine vasopressin and urine osmolality increased during deterioration of respiratory illness, mask ventilation, bilateral pneumothoraces, and severe intraventricular haemorrhage. The data show that inappropriate arginine vasopressin secretion is common during illness in the first week of life in preterm infants and that strict attention must be paid to water balance during this time.
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