Positive end-expiratory pressure during resuscitation at birth in very-low birth weight infants: A randomized-controlled pilot trial

Background: There is limited evidence of the effect of positive end-expiratory pressure (PEEP) during resuscitation soon after birth. Premature neonates may experience respiratory distress from surfactant insufficiency and providing PEEP after the very first breath, may improve outcomes following appropriate resuscitation. The objective of this study was to evaluate the short term respiratory outcomes after positive pressure ventilation (PPV) with PEEP in preterm infants at birth. Methods: A prospective randomized-controlled, pilot trial was conducted. Premature neonates ≤ 32 weeks gestational age or birth weight < 1500 g were recruited. Subjects were allocated to either PEEP of 5 cm H2O (PEEP-5) or no PEEP (PEEP-0) if PPV was administered. Pre-ductal, peripheral capillary oxygen saturation (SpO2) and fraction of inspired oxygen concentration (FiO2) were monitored at 1, 3, 5, 10, 15, and 20 min after birth. FiO2 was adjusted to achieve targeted SpO2 using the 2010 neonatal resuscitation protocol guidelines. Results: 56% (14/25; PEEP-0) and 50% (13/26; PEEP-5) infants received PPV. Mean gestational age was 30 (PEEP-0) vs 31 (PEEP-5) weeks. The mean [SD] birthweight (g) of PEEP-0 was significantly lower than PEEP-5 (1050.4 [262.7] vs 1218.8 [236.8], p = 0.02). Pre-ductal SpO2, FiO2 delivered at each time point, and rates of pneumothorax, surfactant administration and oxygen dependency at 36 weeks postmenstrual age or death was similar. Conclusion: Due to the small sample size and potential bias accrued through random allocation of higher birthweight infants to the PEEP-5 group, the results did not confirm differences in outcomes between the groups, despite evidence favoring postnatal ventilation with PEEP. A further randomized, controlled clinical trial with a larger sample size is warranted to determine the utility and safety of PEEP during the resuscitation of premature infants immediately after birth. Key Words: neonatal resuscitation, oxygen saturation, positive end-expiratory pressure, positive-pressure ventilation, preter

Small-Molecule Vasopressin-2 Receptor Antagonist Identified by a G-Protein Coupled Receptor &quot;Pathway&quot; Screen

ABSTRACT G-protein-coupled receptors (GPCRs) such as the vasopressin-2 receptor (V 2 R) are an important class of drug targets. We developed an efficient screen for GPCR-induced cAMP elevation using as read-out cAMP activation of cystic fibrosis transmembrane conductance regulator (CFTR) Cl Ϫ channels. Fischer rat thyroid cells expressing CFTR and a halide-sensing yellow fluorescent protein (H148Q/I152L) were transfected with V 2 R. Increased cell Cl Ϫ conductance after agonist-induced cAMP elevation was assayed using a plate reader from cell fluorescence after solution I Ϫ addition. The ZЈ factor for the assay was ϳ0.7 with the V 2 R agonist [deamino-Cys1, Val4, D-Arg8]-vasopressin (1 nM) as positive control. Primary screening of 50,000 small molecules yielded a novel, 5-aryl-4-benzoyl-3-hydroxy-1-(2-arylethyl)-2H-pyrrol-2-one class of V 2 R antagonists that are unrelated structurally to known V 2 R antagonists. The most potent compound, V 2 R inh -02, which was identified by screening 35 structural analogs, competitively inhibited V 2 R-induced cAMP elevation with K i value of ϳ70 nM and fully displaced radiolabeled vasopressin in binding experiments. V 2 R inh -02 did not inhibit forskolin or ␤ 2 -adrenergic receptor-induced cAMP production and was more than 50 times more potent for V 2 R than for V 1a R. The favorable in vitro properties of the pyrrol-2-one antagonists suggests their potential usefulness in aquaretic applications. The CFTR-linked cAMP assay developed here is applicable for efficient, high-throughput identification of modulators of cAMP-coupled GPCRs

Thiophenecarboxylate Suppressor of Cyclic Nucleotides Discovered in a Small-Molecule Screen Blocks Toxin-Induced Intestinal Fluid SecretionS⃞

We carried out a “pathway” screen of 50,000 small molecules to identify novel modulators of cAMP signaling. One class of compounds, the 2-(acylamino)-3-thiophenecarboxylates, strongly suppressed cAMP and cGMP in multiple cell lines in response to different agonists acting on G-protein-coupled receptors, adenylyl cyclase, and guanylyl cyclase. The best compounds from structure-activity analysis of 124 analogs, including several synthesized chiral analogs, had and IC50 of <5 μM for suppression of agonist-induced cAMP and cGMP elevation. Measurements of cAMP, cGMP, and downstream signaling in response to various activators/inhibitors suggested that the 2-(acylamino)-3-thiophenecarboxylates function as nonselective phosphodiesterase activators, although it was not determined whether their action on phosphodiesterases is direct or indirect. The 2-(acylamino)-3-thiophenecarboxylates suppressed CFTR-mediated Cl- current in T84 colonic cells in response to cholera and Escherichia coli (STa) toxins, and prevented intestinal fluid accumulation in a closed-loop mouse model of secretory diarrhea. They also prevented cyst growth in an in vitro renal epithelial cell model of polycystic kidney disease. The 2-(acylamino)-3-thiophenecarboxylates represent the first small-molecule cyclic nucleotide suppressors, whose potential therapeutic indications include secretory diarrheas, polycystic kidney disease, and growth inhibition of cAMP-dependent tumors

TITLE PAGE Small-Molecule Vasopressin-2 Receptor Antagonist Identified by a G- Protein Coupled Receptor &apos;Pathway&apos; Screen MOL #34496 2 RUNNING TITLE PAGE Running title: Small-molecule V 2 R antagonist Corresponding author: Number of text pages: 31 Number o

Number of references: 40 Number of words in Abstract: 200 Number of words in Introduction: 496 Number of words in Discussion: 1,102 List of abbreviations: GPCR, G-protein coupled receptor; cAMP, cyclic adenosine monophospate; CFTR