Pediatric research
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The Fas-Fas ligand system is important for apoptosis of activated immune cells. Perturbation of this system occurs in diseases with dysregulated inflammation. Increased soluble Fas (sFas) occurs in systemic inflammatory response syndrome (SIRS) and can block apoptosis. ⋯ Plasma sFas, sFasL, IL-6, IL-10, nitrite + nitrates, and organ failure scores were measured on d 1 and d 3 in 92 children with severe sepsis and 12 critically ill control children. sFas levels were increased in severe sepsis, continued to increase in persistent MOF and nonsurvivors, and were correlated with serum inflammatory markers (IL-6, IL-10, nitrite + nitrate levels). In contrast, sFasL was not increased in severe sepsis and did not correlate with inflammation. sFasL was, however, increased in liver failure-associated MOF and in nonsurvivors, and was associated with viral infection. At autopsy, hepatocyte destruction and lymphocyte infiltration were associated with increased sFas and sFasL levels. sFas may interfere with activated immune cell death and contribute to dysregulation of inflammation, worsening outcome from severe sepsis. sFasL may contribute to hepatic injury and the development of liver failure-associated MOF.
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Comparative Study
The risk of mortality or cerebral palsy in twins: a collaborative population-based study.
The purpose of the paper was to describe demographic and clinical factors associated with fetal or neonatal death or cerebral palsy (CP) in twins. Vital statistics from five populations in the United States and Australia, which included information on CP diagnosed after 1 y of age. Information on zygosity was not available. ⋯ In this large data set spanning a 10-y period, overall rates of death or cerebral palsy were higher in twins than singletons, although small twins generally did better than small singletons. Co-twin death was a strong predictor of CP in surviving twins. This risk was the same for same- and different-sex pairs, and observed both for preterm and term infants.
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In the healthy animal lung, high-frequency oscillatory ventilation (HFOV) achieves effective ventilation at tidal volumes (V(T)) less than or equal to dead space while generating very small pressure fluctuations in the alveolar spaces (deltaP(A)). We hypothesized that the respiratory mechanical parameters influence the magnitude of the intrapulmonary pressure fluctuations during HFOV. A computer model of the neonatal respiratory system was used to examine the independent effects of altering the compliance, nonlinear and linear resistance, and inertance of the respiratory system on V(T), and cyclic intrapulmonary pressures under homogeneous and heterogeneous conditions. ⋯ The deltaP(A)/deltaP(ao) also decreased with increasing alveolar compartment compliance, a finding that was verified in the preterm lamb lung. There was an exponential decrease in the magnitude of deltaP(A1) compared with deltaP(A2) as the ratio of the time constants of the two parallel compartments (tau(1)/tau(2)) increased in the heterogeneous computer lung model. The transmission of driving pressure amplitude to both the proximal airways and lung tissue during HFOV is dependent on lung mechanics and may be greater in the poorly compliant lung than that observed previously in experiments on healthy animals.
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Nonketotic hyperglycinemia is a life-threatening disorder in neonates characterized by a deficiency of the glycine cleavage system. We report on four cases of the neonatal form of the disease, which were investigated by in vitro(1)H magnetic resonance spectroscopy of blood and cerebrospinal fluid, and in vivo(1)H magnetic resonance spectroscopy of brain. ⋯ A recurrent decrease of glutamine and citrate was observed in cerebrospinal fluid, which might be related to abnormal glutamine metabolism in brain. Finally, the cerebral N-acetylaspartate to myo-inositol-glycine ratio was identified as a prognostic indicator of the disease.
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Comparative Study
Partial liquid ventilation versus conventional mechanical ventilation with high PEEP and moderate tidal volume in acute respiratory failure in piglets.
This prospective randomized pilot study aimed to test the hypotheses that partial liquid ventilation combined with a high positive end-expiratory pressure (PEEP) and a moderate tidal volume results in improved gas exchange and lung mechanics without negative hemodynamic influences compared with conventional mechanical ventilation in acute lung injury in piglets. Acute lung injury was induced in 12 piglets weighing 9.0 +/- 2.4 kg by repeated i.v. injections of oleic acid and repeated lung lavages. Thereafter, the animals were randomly assigned either to partial liquid ventilation (n = 6) or conventional mechanical ventilation (n = 6) at a fractional concentration of inspired O(2) of 1.0, a PEEP of 1.2 kPa, a tidal volume < 10 mL/kg body weight (bw), a respiratory rate of 24 breaths/min, and an inspiratory/expiratory ratio of 1:2. ⋯ Dead space ventilation appeared to be lower during partial liquid ventilation compared with conventional mechanical ventilation. No significant differences were observed in airway pressures, pulmonary compliance, and airway resistance between both groups. The results of this pilot study suggest that partial liquid ventilation combined with high PEEP and moderate tidal volume improves oxygenation, dead space ventilation, cardiac output, and oxygen delivery compared with conventional mechanical ventilation in acute lung injury in piglets but has no significant influence on lung mechanics.