Early human development
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Early human development · Nov 1998
ReviewThe 'pharmacology' of neuronal rescue with cerebral hypothermia.
The neuroprotective effects of hypothermia during cerebral ischaemia or asphyxia are well known. Although, in view of this, the possibility of a therapeutic role for hypothermia during or after resuscitation from such insults has been a long standing focus of research, early studies had limited and contradictory results. Clinically and experimentally severe perinatal asphyxial injury is associated with a latent phase after reperfusion, with initial recovery of cerebral energy metabolism but EEG suppression, followed by a secondary phase with seizures, cytotoxic edema, accumulation of cytotoxins, and cerebral energy failure from 6 to 15 h after birth. ⋯ Moderate cerebral hypothermia initiated in the latent phase, between one and as late as 6 hours after reperfusion, and continued for a sufficient duration in relation to the severity of the cerebral injury, has been associated with potent, long-lasting neuroprotection in both adult and perinatal species. These encouraging results must be balanced against the adverse systemic effects of hypothermia. Randomised clinical trials are in progress to establish the safety and efficacy of prolonged cerebral hypothermia.
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Bronchopulmonary dysplasia (BPD)/chronic lung disease occurs primarily in very low birth weight infants (VLBW) often without antecedent severe respiratory distress syndrome. The BPD in these VLBW infants results in less fibrosis than the traditional BPD but the normal process of alveolarization seems to be disrupted. This review develops the thesis that BPD in VLBW infants results from inflammatory mediators interfering with the signaling required for normal late gestational lung development. ⋯ The preterm lung is highly susceptible to injury during resuscitation or more chronic mechanical ventilation because the gas volumes/kg body weight of the lungs are small. An understanding of what causes cytokine release and how cytokines influence lung development is necessary to develop targeted therapies to minimize BPD. However, care strategies that minimize inflammation and ventilator-induced lung injury should help decrease BPD.