Studies in adult animal models of transient @entity7853 (HI) and @entity63 suggest that morphologic evidence of @entity528 in some regions such as striatum appears early, while in other regions such as cerebral cortex and @entity1249 region of hippocampus it is delayed for few days and is referred to as delayed @entity528 (DND). Moreover, in some regions such as @entity1250 / @entity1251 early 'reactive' neuronal changes occur that are potentially reversible. The aim of this study was to determine whether such changes may also occur in the developing brain. To that end, unilateral cerebral HI was produced in postnatal @entity35 of 13, 21, and 30 days (p13, @entity7504 , p30) by right common carotid artery ligation and @entity519 (breathing 8% O2), and their brains were examined at 24 h, 36 h, 72 h, and 96 h of recovery. The results suggest that: (i) DND is present in developing brain, but its regional distribution varies with animals' age. In cerebral cortex, it is more pronounced in p30 @entity35 than in younger animals. In hippocampus, comparison of lesions of similar severity at different age groups shows a more pronounced DND in @entity1250 / @entity1251 region of p13 @entity35 than in older animals, but no significant differences exist in the degree of DND in @entity1249 neurons among different age groups. (ii) 'Reactive' neuronal changes characterized by reduction in Nissl staining and acidophilia of neuronal perikaryon with minimal nuclear abnormality are present at 24 h of recovery. These changes in some regions, such as in @entity1249 and cortex, progress to @entity528 , while in other regions such as in @entity1250 / @entity1251 are potentially reversible. (iii) Recovery of reactive neurons in @entity1250 / @entity1251 region is age dependent in that there is significant recovery in the older age groups, but not in p13 @entity35 . The pathogenetic mechanisms of the reactive neuronal changes, the chain of events leading to DND or neuronal recovery, and the influence of age in these processes remain to be elucidated.

Temporal evolution of neuronal changes in @entity7853 in developing XXXX : a quantitative light microscopic study.

@entity7504 :: ('24525(Tax:10116)', 'Gene') :: ['p21'] @entity1249 :: ('310218(Tax:10116)', 'Gene') :: ['CA1'] @entity63 :: ('MESH:D007511', 'Disease') :: ['ischemia'] @entity7853 :: ('MESH:D020925', 'Disease') :: ['cerebral hypoxia-ischemia'] @entity519 :: ('MESH:D000860', 'Disease') :: ['hypoxemia'] @entity1250 :: ('54231(Tax:10116)', 'Gene') :: ['CA2'] @entity1251 :: ('54232(Tax:10116)', 'Gene') :: ['CA3'] @entity35 :: ('10116', 'Species') :: ['rats'] @entity528 :: ('MESH:D009410', 'Disease') :: ['neuronal death']
@entity35 :: (10116,Species) :: ['rats']
