Bidirectional control of CNS capillary diameter by pericytes.

Neural activity increases local blood flow in the central nervous system (CNS), which is the basis of BOLD (blood oxygen level dependent) and PET (positron emission tomography) functional imaging techniques. Blood flow is assumed to be regulated by precapillary arterioles, because capillaries lack smooth muscle. However, most (65%) noradrenergic innervation of CNS blood vessels terminates near capillaries rather than arterioles, and in muscle and brain a dilatory signal propagates from vessels near metabolically active cells to precapillary arterioles, suggesting that blood flow control is initiated in capillaries.

Gap junctions modulate interkinetic nuclear movement in retinal progenitor cells.

During early retinal development, progenitor cells must divide repeatedly to expand the progenitor pool. During G(1) and G(2) of the cell cycle, progenitor cell nuclei migrate back-and-forth across the proliferative zone in a process termed interkinetic nuclear movement. Because division can only occur at the ventricular surface, factors that affect the speed of nuclear movement could modulate the duration of the cell cycle.

Differential effect of dopamine on mitosis in early postnatal albino and pigmented rat retinae.

Insufficient levels of L-DOPA, released from the retinal pigment epithelium (RPE), in albino animals are considered responsible for the abnormal development of the underlying neural retina. L-DOPA normalizes retinal neurogenesis by reducing levels of cell proliferation either by acting on the cells directly or by being converted into dopamine. Here we report the effects of dopamine on mitosis in early postnatal neural retinae from albino and pigmented rats, using 4D (x, y, z and time) confocal microscopy.

The sterility of hospital-prepared Soffban bandages.

An evaluation of the sterility of hospital-prepared Soffban bandages was undertaken. Discs of Bacillus stearothermophilus were inserted into the bandage rolls, prior to sterilization in "porous load" autoclaves. The discs were subsequently removed and placed in culture media, with growth of the organism indicating failure of sterilization.

ATP released via gap junction hemichannels from the pigment epithelium regulates neural retinal progenitor proliferation.

The retinal pigment epithelium (RPE) plays an essential role in the normal development of the underlying neural retina, but the mechanisms by which this regulation occurs are largely unknown. Ca2+ transients, induced by the neurotransmitter ATP acting on purinergic receptors, both increase proliferation and stimulate DNA synthesis in neural retinal progenitor cells. Here, we show that the RPE regulates proliferation in the underlying neural retina by the release of a soluble factor and identify that factor as ATP.