Robert Schwartz

The Infant of the Diabetic Mother

Although there has been continuing improvement in outcome for infants born to diabetic mothers, they remain a high-risk population needing expert neonatal supervision preceded by meticulous medical-obstetric care. This article evaluates many of the difficulties that the infant of the diabetic mother may encounter, analyzes the pathophysiologic basis for their occurrence, and outlines specific rationale for treatment.

Chronic Maternal Hyperinsulinemia and Hypoglycemia

Chronic hypoglycemia was produced in pregnant rats during the last third of gestation through the constant infusion of insulin by a subcutaneously implanted, osmotically driven minipump. The offspring

'Minor hemoglobins': an alternative approach for evaluating glucose control in pregnancy.

Minor hemoglobins (Hb AI) were measured in 178 women during pregnancy and immediately postpartum by a thiobarbituric acid spectrophotometric method. The patients were classified according to an oral glucose tolerance test (GTT) and an assessment of risk factors for diabetes in normal (n = 75), probably normal (n = 72) and chemical diabetics (n = 26). 5 pregnant insulin-dependent diabetics were also studied. Hb AI was unchanged during the second and third trimesters of pregnancy and immediately postpartum (less than 6 days) in women with normal glucose tolerance. Moreover, no difference of Hb AI level was found when compared with a separate group of nonpregnant individuals (n = 15). Chemical diabetics had significantly higher mean third trimester and postpartum Hb AI than normals (p less than 0.001). The highest Hb AI levels during pregnancy were found in the insulin-dependent diabetics, although these were lower compared to a separate group of nonpregnant insulin-dependent diabetics (n = 10; p less than 0.05). During pregnancy, a significant correlation was found between Hb AI and the 2-hour value of the GTT (p less than 0.001). A positive correlation was also found between third trimester maternal Hb AI and infant birth weight (p less than 0.001). Hb AI may complement other parameters in evaluating maternal glucose tolerance during pregnancy.

Behavioral consequences of neonatal hypoglycemia in the rhesus monkey: A preliminary report*

Three behavioral tests were conducted on each of two young rhesus monkeys, one of which (Animal 1-80) had 6–12 hr. of symptomatic neonatal hypoglycemia, and the other (Animal 315-80) not more than one hr. Animal 1-80 took considerably longer to adapt to the behavioral test apparatus than either Animal 315-80 or a group of 16 control animals. Animal 1-80 was also much slower than either 315-80 or the control animals at learning two complex visual discrimination tasks, the learning set, and delayed matching to sample tasks. The performance of animal 315-80 was indistinguishable from that of the control animals on all tests. The results suggest long-term effects of prolonged symptomatic neonatal hypoglycemia on aspects of emotional behavior and complex cognitive functions.

Evidence for the existence of phosphoenolpyruvate carboxykinase ferroactivator activity in adult and fetal guinea pigs.

Newborn (24--72 h) guinea pig liver cytosolic phosphoenolpyruvate carboxykinase (PEPCK) activity is increased by incubation of the cytosol with the metal salts FeCl2, MnCl2, CoCl2 and CdCl2. FeCl2 at 30 micromol/l concentration is the most effective activator causing a 3.5-fold increase in activity. Purified rat liver cytosolic PEPCK is activated by 30 mumol/l FeCl2 in the presence of liver cytosol of fetal and newborn guinea pigs. These results confirm the existence of PEPCK ferroactivator in the guinea pig which has properties similar to the one found in rat liver. The tissue distribution of ferroactivator activity parallels that of cytosolic PEPCK, being highest in the gluconeogenic organs liver and kidney. Hepatic PEPCK ferroactivator activity can be demonstrated by day 45 of gestation, increasing linearly in specific activity to adult levels at term (65 days). The distribution and development of the ferroactivator is consistent with the hypothesis that it may play a role in the physiologic control of PEPCK.

Fetal and Neonatal Brain Injury: Hypoglycemia in the neonate

After a brief history of the development of neonatal hypoglycemia, this review emphasizes the current approach to the anticipation, diagnosis, and management of the neonate with a low plasma glucose concentration. Both transient and recurrent or persistent hypoglycemia are discussed. Current techniques for studying the neurophysiologic and endocrine-metabolic effects of significant hypoglycemia provide new approaches for establishing relevant definitions of significant hypoglycemia, its prognosis, and pathogenesis. The inadequacy of glucose oxidase strips for screening, the definition of high risk infants, new definitions for low plasma glucose concentrations and their treatment are discussed. New data concerning the hereditary aspects of hyperinsulinemia, the role of glucose transporters, and the ability of the neonate to respond to significantly low glucose values are presented as well.