Impact on neonatal morbidities after a change in policy to administer antenatal corticosteroids to mothers at risk for late preterm delivery.

OBJECTIVES: Antenatal corticosteroids (ACS) administered to mothers at risk for preterm delivery before 34 weeks has been standard care to improve neonatal outcomes. After introducing a new obstetric policy based on updated recommendations advising the administration of ACS to pregnant women at risk for late preterm (LPT) delivery (34-36 6/7 weeks), we set out to determine the short-term clinical impact on those LPT neonates. METHODS: Retrospective chart review of LPT neonates delivered at NYU Langone Medical Center both one year before and after the policy went into place. We excluded subjects born to mothers with pre-gestational diabetes, multiple gestations, and those with congenital/genetic abnormalities. We also excluded subjects whose mothers already received ACS previously in pregnancy. Subjects were divided into pre-policy and post-policy groups. Neonatal and maternal data were compared for both groups. RESULTS: 388 subjects; 180 in the pre-policy and 208 in the post-policy group. This policy change resulted in a significant increase in ACS administration to mothers who delivered LPT neonates (67.3 vs. 20.6%, p<0.001). In turn, there was a significant reduction in LPT neonatal intensive care unit (NICU) admissions (44.2 vs. 54.4%, p=0.04) and need for respiratory support (27.9 vs. 42.8%, p<0.01). However, we also found an increased incidence of hypoglycemia (49.5 vs. 28.3%, p<0.001). CONCLUSIONS: This LPT ACS policy appears effective in reducing the need for LPT NICU level care overall. However, clinicians must be attentive to monitor for adverse effects like hypoglycemia, and there remains a need for better understanding of potential long-term impacts.

The Impact of Circulating Antibody on Group B Streptococcus Intestinal Colonization and Invasive Disease.

Gastrointestinal (GI) colonization with group B Streptococcus (GBS) is an important precursor to late-onset (LO) disease in infants. The host-pathogen interactions that mediate progression to invasive disease remain unknown due, in part, to a paucity of robust model systems. Passively acquired maternal GBS-specific antibodies protect newborns from early-onset disease, yet their impact on GI colonization and LO disease is unexplored. Using murine models of both perinatal and postnatal GBS acquisition, we assessed the kinetics of GBS GI colonization, progression to invasive disease, and the role of GBS-specific IgG production in exposed offspring and juvenile mice at age 12 and 14 days, respectively. We defined LO disease as >7 days of life in the perinatal model. We studied the impact of maternal immunization using a whole-cell GBS vaccine on the duration of intestinal colonization and progression to invasive disease after postnatal GBS exposure in offspring. Animals exhibit sustained GI colonization following both perinatal and postnatal exposure to GBS, with 21% and 27%, respectively, developing invasive disease. Intestinal colonization with GBS induces an endogenous IgG response within 20 days of exposure. Maternal vaccination with whole-cell GBS induces production of GBS-specific IgG in dams that is vertically transmitted to their offspring but does not decrease the duration of GBS intestinal colonization or reduce LO mortality following postnatal GBS exposure. Both perinatal and postnatal murine models of GBS acquisition closely recapitulate the human disease state, in which GBS colonizes the intestine and causes LO disease. We demonstrate both endogenous production of anti-GBS IgG in juvenile mice and vertical transfer of antibodies to offspring following maternal vaccination. These models serve as a platform to study critical host-pathogen interactions that mediate LO GBS disease.

Hyponatremic Seizures and Adrenal Hypoplasia Congenita in a Neonate with Congenital Diaphragmatic Hernia.

Congenital diaphragmatic hernia (CDH) in neonates may occur as an isolated finding, in association with other anomalies, or as part of a genetic syndrome. We report the first case of an infant with CDH who presented with hyponatremic seizures due to adrenal hypoplasia congenita (AHC). The patient underwent repair of CDH defect. After an uncomplicated postoperative course while on discharge planning, he developed a seizure episode associated with severe hyponatremia and hyperkalemia. Extensive diagnostic workup revealed an NR0B1 gene variant confirming the diagnosis of X-linked AHC. The patient was eventually discharged home on hydrocortisone, fludrocortisone, and salt supplements. There are a few case reports of adrenal insufficiency in neonates with CDH, manifesting with symptoms before and immediately after reparative surgery. Clinical presentation of our patient was unique in manifesting as neonatal seizure secondary to severe hyponatremia after a stable postoperative phase. The patient's electrolytes and hemodynamic status remained stable before, during, and after surgery for CDH. This case underlines the importance of taking detailed family history and continued vigilance for signs and symptoms of adrenal insufficiency in infants with repaired CDH by pediatricians and intensivists.

The composition of the inner nuclear layer of the cat retina.

The cellular composition of the inner nuclear layer (INL) is largely conserved among mammals. Studies of rabbit, monkey, and mouse retinas have shown that bipolar, amacrine, Müller, and horizontal cells make up constant fractions of the INL (42, 35, 20, and 3%, respectively); these proportions remain relatively constant at all retinal eccentricities. The purpose of our study was to test whether the organization of cat retina is similar to that of other mammalian retinas. Fixed retinas were embedded in plastic, serially sectioned at a thickness of 1 microm, stained, and imaged at high power in the light microscope. Bipolar, amacrine, Müller, and horizontal cells were classified and counted according to established morphological criteria. Additional sets of sections were processed for protein kinase C and calretinin immunoreactivity to determine the relative fraction of rod bipolar and AII amacrine cells. Our results show that the organization of INL in the cat retina contains species-specific alterations in the composition of the INL tied to the large fraction of rod photoreceptors. Compared with other mammalian retinas, cat retinas show an expansion of the rod pathway with rod bipolar cells accounting for about 70% of all bipolar cells and AII cells accounting for nearly a quarter of all amacrine cells. Our results suggest that evolutionary pressures in cats over time have refined their retinal organization to suit its ecological niche.

The Drosophila RNA-binding protein Lark is required for localization of Dmoesin to the oocyte cortex during oogenesis.

The RNA-binding protein Lark has an essential maternal role during Drosophila oogenesis. Elimination of maternal expression results in defects in cytoplasmic dumping and actin cytoskeletal organization in nurse cells. The function of this protein is dependent on the activity of one or more N-terminal RNA-binding domains. Here, we report the identification of Dmoesin (Dmoe) as a candidate RNA target of Lark during oogenesis. In addition to actin defects in the nurse cells of lark mutant ovaries, we observed mislocalization of posteriorly localized mRNAs including oskar and germ cell less in the developing oocyte. Anteriorly and dorsally localized mRNAs were not affected. In addition, we observed displacement of the actin cytoskeleton from the oocyte plasma membrane. These phenotypes are reminiscent of mutations in Dmoe and suggested that this RNA maybe a potential target of Lark. We observed a significant decrease in Dmoe protein associated with the membrane of the developing oocyte with no changes in expression or localization within the nurse cells. Evidence for an association between Lark protein and moe RNA during oogenesis comes from results of a microarray-based Ribonomics approach to identify Lark RNA targets. Thus, our results provide evidence that Dmoe RNA is a target of Lark during oogenesis and that it likely regulates either the splicing or translation of this RNA.