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Biomedical subjects

A Lucas

Publications and source records attributed to A Lucas.

At least 379 records · Page 21Linked to original sources
PubMed1978

Plasma-prostaglandins in pre-term neonates before and after treatment for patient ductus arteriosus.

9 pre-term babies with patent ductus arteriosus (P.D.A.) and cardiac failure were found to have significantly higher plasma-levels of three prostaglandins (P.G.E, P.G.F, and P.G.FM) than a group of normal pre-term infants of the same age. There was no difference in the plasma-prostaglandin levels before and after surgery in the 5 infants who underwent ligation of the ductus, suggesting that the high P.G. levels are not the result of a patent ductus, but that P.G.S may have a role in the pathogenesis of P.D.A. 3 infants who were treated by indomethacin (a P.G. synthetase inhibitor) showed a sharp initial drop in plasma-levels of the three P.G.S, but levels of P.G.F and P.G.FM had risen either during or within 48 h of completion of the course of indomethacin. These results may explain why high failure-rates have been reported for treatment of P.D.A. by indomethacin.

Ductus Arteriosus, Patent↗
PubMed1978

Creamatocrit: simple clinical technique for estimating fat concentration and energy value of human milk.

A simple micromethod has been devised for estimating the fat and energy content of human milk based on the centrifugation of milk in a haematocrit centrifuge. The percentage of cream, or "creamatocrit," is read from the haematocrit capillary tube and is linearly related to the fat and energy content. The technique, which is rapid and cheap, may be used in clinical practice, in research, and in epidemiological studies.

Centrifugation↗
PubMed1978

Plasma prostaglandin levels during early neonatal life following term and pre-term delivery.

The concentrations of prostaglandin E (PGE), prostaglandin F (PGF) and 13,14-dihydro-15-oxo-PGF (PGFM) have been measured by sensitive and specific radioimmunoassays in neonatal plasma after term and pre-term delivery. Blood samples were taken in the term delivery group from the umbilical artery at birth and on the sixth post-natal day and after pre-term delivery at 2-4 days, on the sixth day, at 2-4 weeks and at 5-8 weeks after birth. The levels of prostaglandins circulating during the first month of life were far greater than those found in normal adults. In neonates delivered at term the plasma concentration of PGE was significantly lower six days after delivery compared with the concentration at delivery whereas the concentrations of PGF and PGFM were essentially unchanged. Following pre-term delivery prostaglandin concentrations declined with increasing neonatal age although only levels of PGE at 5-8 weeks of age were within the normal range of adult values. Comparison of prostaglandin levels six days after delivery between neonates born at term and pre-term showed no significant differences. These results suggest that prematurity per se is not associated with marked abnormalities in the ability of the neonate to synthesize or metabolize prostaglandins.

Age Factors↗
PubMed1978

Selective elevation of circulating prostaglandin concentrations in hyaline membrane disease in pre-term infants.

The plasma concentrations of prostaglandins E and F (PGE, PGF) and 13, 14-dihydro-15-keto-PGF (PGFM) have been measured in pre-term neonates with hyaline membrane disease (HMD) and controls. The concentrations of PGF and PGFM were significantly higher in infants having HMD with a disproportionate increase in PGFM levels for the increase in PGF found. The vasoconstrictor nature of PGF may contribute to the morbidity associated with HMD and the possible therapeutic benefit from the use of prostaglandin synthetase inhibitors is discussed.

Humans↗
PubMed1978

The biology of human drip breast milk.

The milk which drips from the opposite breast during breast feeding is used in some centres for feeding premature babies, yet there is little scientific information on the biology of this secretion. Drip breast milk (DBM) differs from expressed breast milk (EBM), both in its contents and in the change in its composition over the period of lactation. The fat concentration and energy value of DBM are low, compared with levels reported for EBM: protein, fat, sodium and energy value in DBM fall with the duration of lactation, whereas magnesium and calcium rise, and lactose, potassium osmolality and lysozyme remain constant. The milk fat content of DBM produced by individual donors is linearly related to the daily volume of DBM produced. Studies on 477 women admitted to the Oxford General Practice Obstetric Unit over 1 yr showed that, of the 75% who were lactating successfully 2 wk after delivery, 19% were producing DBM by 2--4 wk. Women who produced DBM did not differ in age or parity from those lactating women who did not, and their babies did not differ in birthweight, gestation, centile or sex. The suitability of DBM as a food for premature infants is discussed.

Breast↗
PubMed1978

Metabolic and endocrine events at the time of the first feed of human milk in preterm and term infants.

The first feed of breast milk given to a group of 12 term infants was previously shown to increase the levels of blood glucose and plasma insulin, growth hormone (GH), gastrin, and enteroglucagon. We have now studied the effects of the first feed of breast milk in two similar groups of preterm infants, to compare the results with those obtained for the term infant. One group of 8 preterm infants received a bolus (2.5 ml/kg) of breast milk via a nasogastric tube; the other group of 5 infants received a continuous intragastric infusion (2.5 ml/kg per hour) of breast milk. No change occurred in the concentrations of blood glucose, lactate, pyruvate, or ketone bodies, or in plasma insulin, GH, pancreatic glucagon, or enteroglucagon in either the 'bolus fed' or the 'infusion fed' group of preterm infants. Thus the marked metabolic and endocrine changes in term infants after the first feed do not occur in preterm infants with standard methods of feeding.

Blood Glucose↗
PubMed1977

Head circumference as an index of brain weight in the fetus and newborn.

Postmortem brain weight and head circumference were measured in 485 fetuses and newborn infants. A cubic relationship was demonstrated between these two variables in normal infants. Statistically, a significantly larger brain weight for a given head circumference was found in small-for-gestational-age infants.

Brain↗
PubMed1977

The role of activated accessory cells in preventing immunosuppression by hydrocortisone.

The generation of humoral immunity in vitro by normal and antigen-primed mouse spleen cells was suppressed by in vitro treatment with hydrocortisone. Functions of normal and antigen-activated helper T lymphocytes and of accessory cells were inhibited by the corticosteroids. Spleen cells cultured overnight in medium containing fetal bovine serum became highly resistant to the effects of hydrocortisone. Similar resistance was found to occur when spleen cells were cultured with accessory cells that previously had been activated with bacterial lipopolysaccharide. These studies show that immunologically nonspecific processes significantly alter the effects of the steroids on specific immune responses and suggest that accessory cell products modulate T cells in ways which differ from antigen induction.

Animals↗