Pediatric research
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This study is a retrospective, case control study involving 535 preterm infants examining the roles of sequence polymorphisms in genes that mediate host immune responses to bacterial infection in newborn infants. A total of 49 single nucleotide polymorphisms (SNPs) in 19 candidate genes including inflammatory cytokines (IL6, IL10, IL1B, and TNF), cytokine receptors (IL1RN), toll-like receptors (TLR2, TLR4, and TLR5), and cell surface receptors (CD14) were genotyped. Subjects were stratified into three groups (sepsis, suspected sepsis, and control). ⋯ Polymorphisms in TLR2 (rs3804099), TLR5 (rs5744105), IL10 (rs1800896), and PLA2G2A (rs1891320) genes were associated with sepsis. Allelic variants in PLA2G2A and TLR2 were associated with Gram-positive infections, whereas IL10 was associated with Gram-negative infections (p < 0.05). We conclude allelic variations in PLA2G2A, TLR2, TLR5, and IL10 may moderate the predisposition to sepsis in preterm infants.
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The mechanisms underlying the therapeutic function of caffeine on apneas in preterm neonates are not well determined. To better understand these effects, we exposed rat pups from postnatal d 3-12 to chronic intermittent hypoxia (5% O2/100 s every 10 min; 6 cycles/h followed by 1 h at 21% O2, 24 h/d), a model mimicking hypoxemic exposure in apneic neonates. Then, using whole-body plethysmography, we evaluated minute ventilation, apnea frequency, and duration after i.p injection of caffeine citrate (20 mg/kg) or saline under normoxia and in response to either sustained (FiO2 12%, 20 min) or brief (FiO2 5%, 60 s, total 10 episodes of 8 min each) hypoxia. ⋯ This effect was correlated with a decrease in apnea frequency (not duration). On the contrary, caffeine did not change the ventilatory response to sustained or brief hypoxic exposure. These results suggest that the effects of caffeine on apnea depend on increased central normoxic respiratory drive and enhancement of ventilatory long-term facilitation rather than on higher hypoxic ventilatory response.
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Herein, we determined the contribution of mechanical ventilation, hyperoxia and inflammation, individually or combined, to the cytokine/chemokine response of the neonatal lung. Eight-day-old rats were ventilated for 8 h with low ( approximately 3.5 mL/kg), moderate ( approximately 12.5 mL/kg), or high ( approximately 25 mL/kg) tidal volumes (VT) and the cytokine/chemokine response was measured. Next, we tested whether low-VT ventilation with 50% oxygen or a preexisting inflammation induced by lipopolysaccharide (LPS) would modify this response. ⋯ In contrast, low VT up-regulated CXCL-2 levels were reduced to nonventilated levels when LPS-treated newborn rats were ventilated with 50% oxygen. Thus, low-VT ventilation triggers the expression of acute phase cytokines and CXC chemokines in newborn rat lung, which is amplified by oxygen but not by a preexisting inflammation. Depending on the individual cytokine or chemokine, the combination of both oxygen and inflammation intensifies or abrogates the low VT-induced inflammatory response.
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Comparative Study
Effect of sedation and analgesia on postoperative amplitude-integrated EEG in newborn cardiac patients.
The aim of this study is to describe the effect of sedation and analgesia on postoperative amplitude-integrated EEG (aEEG) in newborns with congenital heart disease (CHD) undergoing heart surgery. This is a consecutive series of 26 newborns with CHD of which 16 patients underwent cardiopulmonary bypass (CPB) surgery and 10 patients did not. aEEG was monitored for at least 12 h preoperatively and started within the first 6 h postoperatively for 48 h. Outcome was assessed at 1 year of age. ⋯ Sedation with midazolam has a transient effect on the background activity, whereas fentanyl can induce a severe pathologic background pattern. The significance of these changes on outcome is not yet clear. Thus, more attention should be paid to these effects when interpreting aEEG in this population.
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Comparative Study
Noninvasive respiratory support of juvenile rabbits by high-amplitude bubble continuous positive airway pressure.
Bubble continuous positive airway pressure (B-CPAP) applies small-amplitude, high-frequency oscillations in airway pressure (DeltaPaw) that may improve gas exchange in infants with respiratory disease. We developed a device, high-amplitude B-CPAP (HAB-CPAP), which provides greater DeltaPaw than B-CPAP provides. We studied the effects of different operational parameters on DeltaPaw and volumes of gas delivered to a mechanical infant lung model. ⋯ PaCO2 levels did not differ (p=0.073) among the three bubbler configurations. PRP with HAB-CPAP135 were half of the PRP with HAB-CPAP0 or HAB-CPAP90 (p=0.001). These results indicate that HAB-CPAP135 provides greater respiratory support than conventional B-CPAP does.