19 research outputs found
Formal relational database design: an exercise in extending the formal template language
Changes in the Incidence and Spectrum of Neonatal Septicemia during a Fifteen-year Period
Septicaemia with Coagulase Negative Staphylococci in a Neonatal Intensive Care Unit Risk Factors for Infection, and Antimicrobial Susceptibility of the Bacterial Strains
Early Total Versus Gradually Advanced Enteral Nutrition in Stable Very-Low-Birth-Weight Preterm Neonates: A Randomized, Controlled Trial
Pharmacodynamically optimized erythropoietin treatment combined with phlebotomy reduction predicted to eliminate blood transfusions in selected preterm infants
Assessing Variation in the Cost of Palivizumab for Respiratory Syncytial Virus Prevention in Preterm Infants
Fetal and postnatal ovine mesenteric vascular reactivity
BACKGROUND: Intestinal circulation and mesenteric arterial (MA) reactivity may play a role in preparing the fetus for enteral nutrition. We hypothesized that MA vasoreactivity changes with gestation and vasodilator pathways predominate in the postnatal period. METHODS: Small distal MA rings (0.5-mm diameter) were isolated from fetal (116-d, 128-d, 134-d, and 141-d gestation, term ~ 147 d) and postnatal lambs. Vasoreactivity was evaluated using vasoconstrictors (norepinephrine (NE) after pretreatment with propranolol and endothelin-1(ET-1)) and vasodilators (NO donors A23187 and s-nitrosopenicillamine (SNAP)). Protein and mRNA assays for receptors and enzymes (endothelin receptor A, alpha-adrenergic receptor 1A (ADRA1A), endothelial NO synthase (eNOS), soluble guanylyl cyclase (sGC), and phosphodiesterase5 (PDE5)) were performed in mesenteric arteries. RESULTS: MA constriction to NE and ET-1 peaked at 134 d. Relaxation to A23187 and SNAP was maximal after birth. Basal eNOS activity was low at 134 d. ADRA1A mRNA and protein increasedsignificantlyat134danddecreasedpostnatally.sGC and PDE5 protein increased from 134 to 141 d. CONCLUSION: Mesenteric vasoconstriction predominates in late-preterm gestation (134 d; the postconceptional age with the highest incidence of necrotizing enterocolitis (NEC)) followed by a conversion to vasodilatory influences near the time of full-term birth. Perturbations in this ontogenic mechanism, including preterm birth, may be a risk factor for NEC