Frank H. Morriss

Syndrome of inappropriate antidiuretic hormone secretion in neonates with pneumothorax or atelectasis

Nine episodes of the syndrome of inappropriate antidiuretic hormone secretion occurred in five newborn infants following atelectasis or pneumothorax. All infants had pre-existing lung disease and were being treated with positive pressure ventilation. The mean interval between acute atelectasis or pneumothorax and the development of diagnostic hyponatremia, hypo-osmolal serum, hyperosmolal urine, and oliguria was 13.4 hours. Fluid restriction and removal of the triggering event resulted in resolution of the abnormalities within 1.5 to 4 days. Infants who develop atelectasis or pneumothorax should be evaluated for the subsequent occurrence of SIADH; the administration of a water load to them may result in dilutional hyponatremia, for which fluid restriction, not sodium infusion, is the proper therapy.

Uterine uptake of amino acids throughout gestation in the unstressed ewe

The uterine uptake of 21 amino acids was determined in chronically catheterized ewes from 35 to 145 days of gestation. Total uptake of amino acids increased as gestation progressed as described by the equation: Q (mmoles/kgxa0·xa0day)xa0=xa00.19 gestational age (days)xa0+xa00.30. We were unable to detect a statistically significant correlation of uterine A-V concentration difference and gestational age for most amino acids. The uptakes of only eight amino acids contributed to the total increase (arginine, glutamine, valine, leucine, ornithine, isoleucine, tyrosine, phenylalanine). The amino acids which made the largest contribution to uterine uptake are similar to those which furnish the largest contributions to umbilical uptake previously reported, except for glycine, which exhibits significant umbilical uptake, but no uterine uptake. Glutamate, which is removed by the placenta from the umbilical circulation, exhibited no significant uterine uptake nor production. The total amino acid nitrogen uptake by the uterus extrapolated to 130 days’ gestation, 1.20 gm/kg fetal weightxa0·xa0day, closely approximates the previously reported value for umbilical amino acid nitrogen uptake at 130 days. Comparison of the individual amino acids removed from the uterine circulation with those which enter the umbilical circulation, however, suggests that metabolic conversions which involve glutamate and glycine occur in the placenta.

Effect of maternal serum insulin on umbilical extraction of glucose and lactate in fed and fasted sheep.

In 18 chronically instrumented pregnant ewes in late gestation, umbilical extractions of glucose and lactate were determined before and during the continuous infusion of ovine insulin, 0.25 mU/kg . min, into one uterine artery. Studies were conducted in both well-nourished and fasting ewes. Exogenous insulin increased the umbilical extraction of glucose without altering the umbilical extraction of lactate over the range of concentrations of maternal blood glucose encountered in the fed and fasted states. Moreover, the efflux of lactate into the uterine venous circulation in two additional ewes was not altered by the administration of insulin. These studies support the hypothesis that maternal circulating insulin binds to insulin receptors on the microvillous brush border of the placenta to effect an increase in the carrier-mediated transfer of glucose rather than cause an intraplacental decrease in the catabolism of glucose to lactate. The results suggest that, as maternal levels of blood glucose and serum insulin spontaneously rise in concert over the physiologic range, both factors may contribute to the increasing umbilical extraction of glucose. Furthermore, these observations raise the possibility that decreased binding of insulin by placental insulin receptors, which is reported to occur in placentas from diabetic women, may be accompanied by a relatively decreased umbilical uptake of glucose for a given maternal concentration of glucose, but not of lactate.

Determination of newborn special care bed requirements by application of queuing theory to 1975-1976 morbidity experience

The movement of newborn infants from the delivery room of a level III perinatal center to nursing units that provided different levels of care was prospectively documented for 1975 and 1976. These data were employed in a computer modeling experiment based on sequential queuing theory to determine the relationships between numbers of available intermediate and maximum care nursery beds, the probability that a given newborn arrival could not be accommodated, and the occupancy rates for each level of care. The nursery bed requirements for the level III center were used to estimate the number of special care beds needed by the regional Health Service Area.

Contraplacental Hypogastrinemic Effect of Gastrin Infusion in Sheep

Summary: Infusion of gastrin, G-171, at 0.4 μg/min into either the maternal or fetal venous circulation of six late gestation sheep was associated with increases in serum gastrin concentration in the infused circulation and reciprocal decreases in the serum gastrin concentration in the other circulation (contraplacental) that perfused the placenta. Pentagastrin infusion at 0.4 μg/min was associated with an increase in C-terminal specific gastrin immunoreactivity in both the infused and the contraplacental circulations. These observations suggest that biologically active fragments of gastrin, but not the intact molecule, may cross the ovine placenta. An alternative explanation for our results is that gastrin infusion into either the maternal or fetal circulation which perfuses the placenta may result in the release of an inhibitor (ie., somatostatin) into the other circulation. Of broad importance, these observations indicate that although intact polypeptide hormones may not traverse the placenta, their concentrations in maternal and fetal sera may not be as independent as previously believed. Serum gastrin half-life values in late gestation sheep fetuses, lambs, and ewes were determined to be 13.7 ± 1.9, 16.7 ± 2.6, and 15.2 ± 2.8 min, respectively. These similar values indicate that the relatively high serum gastrin concentrations observed in near-term sheep fetuses are not the result of pro-longed half-life in the fetus.

452 NEONATAL GASTRIC MOTILITY IN DOGS: MATURATION AND RESPONSE TO PENTAGASTRIN

The postnatal development of gastric motility and pH, and the response to pentagastrin (PG) were studied at 10 intervals in 5 beagles from birth to 6 weeks. Motility was monitored using twin single lumen 1.7 mm catheters with 1 mm side openings at the tips which were 2 cm apart. Catheters were perfused with distilled H2O at a constant rate and pressure transducers were interposed in the system. Oral catheter insertion distance to the antrum of the stomach was determined radiographically. Puppies were fasted 3-6 hours prior to study; gastric contents were aspirated, and the stomach rinsed with distilled H2O. After an initial gastric pH determination and a 10-20 min. period of baseline motility monitoring, the response to 8 μ g/kg of s.c. PG was determined.Baseline mean antral contractions increased from 0.25/min on day 1 to 2.0/min on day 1 through weaning in the 4th week when the frequency decreased to < 1.25/min. Fundal contraction frequency and pressure increased during the 3rd week from significantly lower levels than the antrum suggesting the development of propagated peristalsis. Control gastric pH was > 6.0 until day 7 when mean pH was 3.4. PG produced a significant decrease in pH on day 3 (p < 0.05), but the maximum decrease did not appear until day 9 and thereafter (p < 0.005). PG inhibition of the frequency and force of antral contractions was apparent from the 3rd day through the 6th week.These observations in beagle puppies suggest a developmental maturation in gastric motility and acid secretion from birth through the 2nd week, and a delay in responsiveness to PG.