The use of dexamethasone in premature infants to prevent and/or treat bronchopulmonary dysplasia adversely affects neurocognitive development and is associated with cerebral palsy. The underlying mechanisms of these effects are multifactorial and likely include apoptosis. The objective of this study was to confirm whether dexamethasone causes apoptosis in different regions of the developing rat brain. On postnatal day 2, pups in each litter were randomly divided into the dexamethasone-treated (n = 91) or vehicle-treated (n = 92) groups. Rat pups in the dexamethasone group received tapering doses of dexamethasone on postnatal days 3-6 (0.5, 0.25, 0.125, and 0.06 mg/kg/day, respectively). Dexamethasone treatment significantly decreased the gain of body and brain weight and increased brain caspase-3 activity, DNA fragments, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and cleaved caspse-3-positive cells at 24 hr after treatment. Dexamethasone increased cleaved caspse-3-positive cells in the cortex, thalamus, hippocampus, cerebellum, dentate gyrus, and subventricular zone. Double-immunofluorescence studies show that progenitor cells in the subventricular zone and dentate gyrus preferentially undergo apoptosis following dexamethasone exposure. These results indicate that dexamethasone-induced apoptosis in immature cells in developing brain is one of the mechanisms of its neurodegenerative effects in newborn rats.

Hemolytic disease of the fetus and newborn is a common consideration in newborn medicine, especially among the jaundiced. Maternal breastmilk provides numerous benefits to the infant, including nutrition and immunologic factors. Here, we present an infant who received three intrauterine transfusions for anemia secondary to anti-K1 (Kell), anti-C, and anti-e antibodies and whose maternal breastmilk tested positive for anti-Kell antibodies. The infant required another transfusion at 4 weeks of life for anemia. We review the pathophysiology of anti-Kell antibodies, the immunology of breast milk, and the intersection of these two topics.

Effects of intrauterine hypoxia-ischemia (HI) on brain func-thase inhibitor, NMDA-induced cGMP formation was blocked, tional development in the term rat were examined in cerebellar and the blockade of cGMP formation by L-NMMA (10 pM) granule cell cultures obtained from an in utero HI model. On could be reversed by simultaneous application of 1 mM arginine gestation d 17, HI conditions were achieved by complete clamp-in both control and HI cells. Antenatal HI insult (20-35 min) also ing of the uterine vasculature for designated durations followed augmented NMDA-, but not KA-, stimulated accumulation of by removal of the clamps to permit reperfusion. Sham operation extracellular glutamate. The hypersensitive response in NMDA-(surgery without vasculature clamping) was performed as the induced glutamate accumulation could be suppressed by 150 p M control. After surgery, the uterine horns were returned to dam's L-NMMA. The overall results suggest that antenatal HI occurring abdomen to let the pups deliver naturally. Severe HI insult from in the last half of gestation may result chronically in adverse the surgical manipulation was evident in that the lactate levels of effects on NMDA receptor-mediated neurotransmission and that fetal Gain increased, and fetal blood pH decreased with the nitric oxide is possibly involved in these effects. In utero HI is a major contributor to long-term neurologic humans, and brain injury is determined immediately after the abnormalities. The severe sequelae include learning disabili-insult. It is not fully understood whether and how HI occurring ties, motor disturbances, behavioral alterations, and mental retardation (1, 2). The establishment of many perinatal HI animal models (3, 4), including several rat models (5-8), has greatly expanded our knowledge of the critical events and biochemical alterations occurring during or after the initial HI insult. However, in most of these experimental models the HI insult is given acutely near term or during the first a few days of postnatal life (in case of the rat model), which is thought to be a developmental stage equivalent to the third trimester in Received November 18, 1994; accepted March 7, 1995 at a relatively early gestational stage results in chronic adverse effects on CNS development. Recent animal studies have provided evidence that intermittent antenatal hypoxia has longterm effects on rat brain ornithine decarboxylase activity and causes several behavioral changes, although with maturation those abnormal behaviors are not evident (9). Clinical evidence also indicates that neurologic damage in newborn infants due to antenatal insults is demonstrable (10-12) and that the observed neonatal encephalopathy, after the exclusion of infants with major malformations or infections, is not always due to birth asphyxia and is sometimes due to preexisting abnormalities (13). It is thus desirable to have an animal model for

Perinatal hypoxic-ischemic (HI) insult is known to cause cellular and molecular disturbances leading to functional and behavioral abnormalities during brain development. In this study, we examined the effects of an in utero HI insult on poly-phosphoinositide turnover in vivo in the cerebrum and cerebellum as well as cholinergic-stimulated turnover in cortical slices from developing rat brain. In utero HI treatment was carried out by clamping the uterine blood vessels of near-term fetuses for 5, 10 and 15 min followed by resuscitation of the newborn pups. The in vivo protocol for examining poly-PI signaling activity in 2 week-old pup brain involved intracerebral injection of [3H]inositol for 16 hr and subsequent intraperitoneal injection with lithium (8 meq/kg) for 4 hr prior to decapitation. In the control pups, lithium elicited a 2.6 fold increase in labeled inositol phosphate (IP) in the cerebrum as compared to a 1.3 fold increase in the cerebellum. In utero HI insult (5 to 15 min) resulted in a small increase in labeled IP in the cerebrum but not in the cerebellum. Carbachol stimulation of poly-PI turnover was examined in brain slices prelabeled with [3H]inositol in vivo. Incubation of the prelabeled slices with carbachol in the presence of LiCl (10 mM) resulted in a time-, dose- and age-dependent increase in labeled IP. Brain slices from 2 week-old pups that experienced in utero HI-treatment for 10 and 15 min (but not 5 min) showed a significant decrease in carbachol-stimulation of labeled IP as compared with control pups. These results indicate the effects of in utero HI on the choninergic-stimulated poly-PI signaling pathway and its implication on related functional deficits in the developing brain.