Fetal umbilical glucose uptake was compared with simultaneous measurements of glucose turnover and utilization rates in 12 pregnant sheep, at a mean of 137 days gestational age (range, 118-146 days). Umbilical glucose uptake was calculated by application of the Fick principle. Fetal glucose turnover rate was measured by a primed-constant infusion of [14C]- and [3H]glucose (glucose turnover rate = tracer infusion rate divided by fetal glucose sp act). The calculation of fetal glucose utilization rate required substraction of the loss of tracer to the placenta from the tracer infusion rate, thus defining the net tracer entry into the fetus for direct comparison with the net umbilical glucose uptake. In fed, normoglycemic sheep, these measurements demonstrated statistical equivalence of umbilical glucose uptake rate (4.77 mg.min-1.kg-1 +/- 0.34 SE) and glucose utilization rate ([14C]glucose, 5.58 mg.min-1.kg-1 +/- 0.54 SE; and [3H]glucose, 7.19 mg.min-1.kg-1 +/- 1.24 SE) when tested by two-way analysis of variance (P greater than 0.1). In three fasted, hypoglycemic sheep, the umbilical glucose uptake rate fell to 1.43 mg.min-1.kg-1 +/- 0.56 SE, which was considerably lower than the simultaneous glucose utilization rate ([14C]glucose, 4.78 mg.min-1.kg-1 +/- 0.48 SE; and [3H]glucose, 6.81 mg.min-1.kg-1 +/- 2.19 SE). Thus, in the normoglycemic, late-gestation fetal lamb, there appears to be little glucogenesis, whereas glucogenesis may become significant during fasting-induced fetal hypoglycemia.

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Due to the high mortality associated with pulmonary interstitial emphysema in the low-birth-weight infant, a method was developed to predict the infants most at risk for death. This information will allow the discriminant selection of patients for future trials of an alternative method of mechanical ventilation, highfrequency ventilation. During a 3-year-period (July 1, 1979 through June 30, 1982), 70 infants were retrospectively analyzed to determine the clinical parameters important in predicting mortality. The infants at highest risk for death included those of younger gestational age, those with birth weight less than 1,500 g (95% of all mortalities), and those that developed pulmonary interstitial emphysema within the first 24 hours of life. Mortality sharply increased in the infants with birth weight less than 1,500 g whose ventilatory requirements exceeded a peak inspiratory pressure of 25 cm H2O on day 1. Morbidity was high in the survivors as evidenced by a 54% incidence of bronchopulmonary dysplasia. With multivariant analysis, it was possible to isolate the variables (birth weight and highest peak inspiratory pressure on day 1) most influential in predicting mortality and to construct a formula for predicting mortality in the infants with birth weight less than 1,500 g. With a subsequent prospective study of 30 infants, the predictive accuracy of the formula was established.

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of Iowa College Med., Dept. Ped. and Anesth. Iowa City.To evaluate the effect of H and surgery on thyroid and hepati function in the pregnant sheep, 14 date bred ewes from 104 to 1: days gestation were anesthetized with 0.5 to 1.5% H in nitrous oxide and oxygen. The surgical procedure began 15 minutes later and lasted from 2 to 2 112 hours. Serum samples were obtained prior to and at 112 hour intervals for 2 hours after the start c H and at 24 and 48 hours post-operatively (PO). Pre-operatively the mean serum ('SEM) thyroxine (T ) and triiodothyronine (T ) levels were 3.9'0.2 ~g / d l and 117id.3 ngldl, respectively. '?he mean serum T level remained unchanged during the operative procedure but wis elevated at 24 and 48 hours PO. The mean serum T level was lower at 2 hours post-anesthesia (84.8'10.8 ngldl, pi0.025) returning to the pre-operative level by 48 hours. The mean T /T ratio was decreased at 2 and 24 hours post-anesthesia but re?uried to the pre-operative level by 48 hours. Pre-operatively, the mean SGOT ('SEM) level was 8.522.9 IU/L and the SGP? (?SEMI level was 61.7'7.1 IUIL and remained unchanged during the operative procedure. The mean SCOT level was increased at 48 hours PO (21.4'3.8 IUIL, pC0.025) Studies altering plasma calcium levels have demonstrated that the maternal (M) and fetal (F) parathyroid glands appear to func tion automonously and suggest a lack of placental permeability to PTH. To determine whether the ovine placenta is permeable to PTH 1-125, catheters were placed into the F abdominal aorta and pedal vein and M abdominal aorta and jugular vein in 5 date bred ewes at 121 to 135 days gestation. The studies were conducted 24 to 48 hours after surgery when the M and F arterial blood gases and pH returned to normal. Purified intact bovine PTH (1-84) was iodinated by the chloramine-T method. The placenta transfer of tracer quantities of PTH 1-125 was studied in 5 animals in the W F and 4 in the F+M direction. Simultaneous serial F and M plasma samples were obtained during the 60 minute study period and precipitated with 15% trichloracetic acid and the results expressed as percent doselliter plasma. During the initial 20 minutes of the study, the t 112 was 21 minutes (r= -0.99) in the F and 21 minutes in the M (r=-0.99). In the WF studies, no more than 0.3% of the injection doselliter plasma was detected in the F and in the F+M studies, no more than 0.5% of the injected doselliter plasma was detected in the M at 15 tc 30 minutes post injection. Thus, during the 3rd trimester, the ovine placenta is impermeable to PTH 1-125. The t 112 of PTH I-125 is similar in both the ovine F and M. Prostaglandin (PG) biosyntliesis by the mammalian kidney occur! mainly in the medulla (11) and PG breakdown takes place mainly in the cortex (C). We have studied the PG synthetase system in 6 human newborn kidneys (16,22,26,28,31,32 weeks of gestation) 2 hours after death Slices of M and C were incubated in a medium containing 50 ug arachidonic acid (M) and 50 uCi [ 3~] -~. The incorporation of [311]-~ in...