Extubation in the operating room after surgery for congenital heart disease was successful in the majority of patients. The strongest independent risk factors for failure of this strategy included younger age and longer cardiopulmonary bypass time.

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Maple syrup urine disease (MSUD) is an inborn error of metabolism caused by a deficiency in branched chain ␣-keto acid dehydrogenase that can result in neurodegenerative sequelae in human infants. In the present study, increased concentrations of MSUD metabolites, in particular ␣-keto isocaproic acid, specifically induced apoptosis in glial and neuronal cells in culture. Apoptosis was associated with a reduction in cell respiration but without impairment of respiratory chain function, without early changes in mitochondrial membrane potential and without cytochrome c release into the cytosol. Significantly, ␣-keto isocaproic acid also triggered neuronal apoptosis in vivo after intracerebral injection into the developing rat brain. These findings suggest that MSUD neurodegeneration may result, at least in part, from an accumulation of branched chain amino acids and their ␣-keto acid derivatives that trigger apoptosis through a cytochrome c-independent pathway.

Fas/CD95/Apo-1 is a cell surface receptor that transduces apoptotic death signals following activation and has been implicated in triggering apoptosis in infected or damaged cells in disease states. Apoptosis is a major mechanism of neuronal loss following hypoxic-ischemic injury to the developing brain, although the role of Fas in this process has not been studied in detail. In the present study, we have investigated the expression and function of Fas in neuronal cells in vitro and in vivo. Fas was found to be expressed in the 14 day old rat brain, with strongest expression in the cortex, hippocampus and cerebellum. Cross-linking of Fas induced neuronal apoptosis both in neuronal PC12 cells in culture and following intracerebral injection in vivo, indicating that neuronal Fas was functional as a death receptor. This death was shown to be caspase dependent in primary neuronal cultures and was blocked by the selective caspase 8 inhibitor IETD. Finally, cerebral hypoxia-ischemia resulted in a strong lateralised upregulation of Fas in the hippocampus, that peaked six to twelve hours after the insult and was greater on the side of injury. These results suggest that Fas may be involved in neuronal apoptosis following hypoxic-ischemic injury to the developing brain.

Transient unilateral forebrain hypoxia-ischaemia (HI) in 14-day-old rats produces infarction and delayed neuronal death in the frontal cortex. Cell death can also be observed in regions distant from the primary injury, a phenomenon known as diaschisis. While apoptosis is involved in selective neuronal death, its role in infarction and diaschisis remains poorly understood. Here, we have investigated the proteolytic cleavage of poly(ADP ribose) polymerase (PARP) and the occurrence of apoptosis in the hippocampus and the cerebellum following either HI or traumatic brain injury. We demonstrate that: (i) in vitro, PARP is cleaved during apoptosis but not necrosis in cultured neuronal (N1E) cells and Swiss 3T3 fibroblasts; (ii) following HI, apoptotic cells can be detected by 4 h after injury in the hippocampus; (iii) in the ipsilateral hippocampus the appearance of cells with apoptotic morphology is preceded by a dramatic increase in PARP cleavage in the same region, starting immediately following HI and persisting for 24 h; (iv) HI also induces apoptosis in the cerebellum and, as in the hippocampus, the appearance of cells with apoptotic morphology is preceded by PARP cleavage that is greater on the side ipsilateral to forebrain injury; and (v) similarly, traumatic brain injury to the forebrain leads to PARP cleavage and apoptosis in the cerebellum. We conclude that HI injury or traumatic injury to the developing rat forebrain leads to PARP cleavage in directly affected areas and in sites distant from the primary injury that precedes the appearance of cells with apoptotic morphology. Our results are consistent with a role for apoptotic cell death in infarction and in diaschisis resulting from forebrain injury to the developing brain.

Background:Primary repair of tetralogy of Fallot (TOF) has low surgical mortality, but some patients still experience significant postoperative morbidity.Aim:To review our institutional experience with primary TOF repair, and identify predictors of intensive care unit (ICU) morbidity.Settings and Design:Medium-sized pediatric cardiology program. Retrospective study.Subjects and Methods:We retrospectively reviewed all the patients with TOF and pulmonic stenosis who underwent primary repair in infancy at our institution from January 2001 to December 2012. Preoperative, operative, and postoperative demographic and morphologic data were analyzed. ICU morbidity was defined as prolonged ICU stay (≥7 days), and/or prolonged duration of mechanical ventilation (≥48 h).Statistical Analysis Used:Multiple logistic regression analysis.Results:Ninety-seven patients underwent primary surgical repair during the study period. The median age was 4.9 months (1-9 months) and the median weight was 5.3 kg (3.1-9.8 kg). There was no early surgical mortality. Incidence of junctional ectopic tachycardia (JET) and persistent complete heart block was 2 and 1%, respectively. The median length of ICU stay was 6 days (2-21 days) and median duration of mechanical ventilation was 19 h (0-136 h). By multiple regression analysis, age and weight were independent predictors of length of ICU stay, while surgical era was an independent predictor of duration of mechanical ventilation.Conclusion:Primary TOF repair is a safe procedure with low mortality and morbidity in a medium-sized program with outcomes comparable to national standards. Age and weight at the time of surgery remain significant predictors of morbidity.

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Perinatal hypoxic ischaemic brain injury (HII) is a major cause of neonatal mortality and long-term neurological morbidity. An understanding of the molecular events which follow HII may lead to novel treatments to improve the final outcome for affected infants. The beta-amyloid precursor protein (beta-APP) is a widely expressed transmembrane protein whose proposed functions include stabilization of neuronal calcium fluxes, inhibition of the clotting cascade and cell-cell or cell-matrix adhesion. Normally present at low levels in neurons its expression is induced as part of the acute response of the adult brain to HII. This study aimed to determine whether beta-APP is also part of the acute adaptive response of the infant brain to HII. Immunohistochemistry and Western blotting were used to assess cerebral beta-APP expression in 14-day-old rat pups subjected to unilateral HII, and in 10 term human infants, who died between 12 h and 16 months after severe perinatal HII. In the rat pups beta-APP expression was increased by 2 h post-injury, peaked, fourfold above control levels, at 24 h and gradually declined over the following 4 days. Expression was induced bilaterally, but was greater on the side of injury. In the human infants, increased, predominantly neuronal expression of beta-APP, was detectable immunohistochemically within 24 h of injury and was greatest in those infants dying within 3 days. Expression was particularly strong in the areas showing histological evidence of injury, but was also seen in apparently undamaged areas. We conclude that beta-APP induction is part of the the acute adaptive response of the neonatal brain to HII.