Cell stress could be due to infection, injury, ischemia, hypoxia, acidosis and complement lysis. Permanent brain damage may occur due to cerebral hypoxia or opioid-induced neurotoxicity. Most cases affect preterm birth infants and result from placental insufficiency and/or fetal hypoxia. Asphyxia causes generalized hypoxia, which affects primarily the tissues and organs. Insufficient oxygen will lead to cerebral hypoxia and permanent brain damage. Asparagine can be hydroxylated in the HIF1 hypoxia inducible transcription factor. The role of reactive oxygen species in hypoxia sensing is also under question. Also oxygen demand was reduced, thereby protecting against hypoxia. Objective measurements of the severity of cerebral hypoxia depend on the cause. In general, respiratory reflexes such as response to hypoxia diminish. Conditions such as high levels of erythropoesis, iron deficiency and tissue hypoxia inhibit hepcidin expression. They have extensive areas of necrosis and hypoxia. The baby is at increased risk of hypoxia and hypoglycaemia. Travelling above 8,000 feet altitude is a factor in cerebral hypoxia. Twenty-six bodies showed signs of hypoxia (lack of oxygen).