Decreased neurogenesis in aged rats results from loss of granule cell precursors without lengthening of the cell cycle.

It is well established that neurogenesis in the dentate gyrus slows with aging, but it is unclear whether this change is due to slowing of the cell cycle, as occurs during development, or to loss of precursor cells. In the current study, we find that the cell cycle time of granule cell precursors in middle-aged male rats is not significantly different from that in young adults. The size of the precursor pool, however, was 3-4 times smaller in the middle-aged rats, as determined using both cumulative bromodeoxyuridine (BrdU) labeling as well as labeling with the endogenous marker of cell proliferation, proliferating cell nuclear antigen (PCNA).

Early results of single-stage biventricular repair of severe aortic hypoplasia or atresia with ventricular septal defect and normal left ventricle.

Objective: Biventricular repair of aortic atresia (or severe aortic hypoplasia) is possible in the presence of a ventricular septal defect and normal left ventricle. We considered whether primary biventricular repair was a safe alternative in all cases, even in the presence of interrupted aortic arch.

Methods: This was a retrospective analysis of patients who underwent primary biventricular repair consisting of a combination Norwood-type reconstruction of the aortic arch, baffle of the left ventricle to both semilunar roots, and conduit placement from the right ventricle to pulmonary arteries.

A natural form of learning can increase and decrease the survival of new neurons in the dentate gyrus.

Granule cells born in the adult dentate gyrus undergo a 4-week developmental period characterized by high susceptibility to cell death. Two forms of hippocampus-dependent learning have been shown to rescue many of the new neurons during this critical period. Here, we show that a natural form of associative learning, social transmission of food preference (STFP), can either increase or decrease the survival of young granule cells in adult rats.

New GABAergic interneurons in the adult neocortex and striatum are generated from different precursors.

Ongoing neurogenesis in the adult mammalian dentate gyrus and olfactory bulb is generally accepted, but its existence in other adult brain regions is highly controversial. We labeled newly born cells in adult rats with the S-phase marker bromodeoxyuridine (BrdU) and used neuronal markers to characterize new cells at different time points after cell division. In the neocortex and striatum, we found BrdU-labeled cells that expressed each of the eight neuronal markers.

Short-term and long-term survival of new neurons in the rat dentate gyrus.

New neurons continue to be generated in the dentate gyrus throughout adulthood. Previous studies have shown that a significant proportion of new granule cells labeled with the thymidine analogue bromodeoxyuridine (BrdU) are lost from the adult dentate gyrus within 2 weeks. How long this loss continues and the extent to which it represents cell death, as opposed to dilution of label, is unclear.