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Van Norren D.,University Utrecht | Gorgels T.G.M.F.,Institute of the Royal Netherlands Academy of science
Photochemistry and Photobiology | Year: 2011

Photochemical damage to the retina occurs for prolonged exposures of intense light. Two action spectra exist for this phenomenon. In rat an action spectrum matching the absorption spectrum of rhodopsin was found. In macaque, the susceptibility for photochemical damage decreased continuously from the UV to long visible wavelengths. Later, such a spectrum was also found in rat. In search for critical parameters that determine the shape of the spectrum we gathered all available data on the damage threshold dose for monochromatic radiation and noted the experimental conditions. The rhodopsin action spectrum was found in two sources; the other 16 sources adhered to the short wavelength spectrum. Comparing the conditions we conclude that the critical parameters for the generation of either action spectrum remain elusive. Experiments are suggested to resolve this issue and fill a few gaps in our knowledge. In 1966 Noell published his landmark study on photochemical damage of the retina. The action spectrum (in rat) was identical to the absorption spectrum of rhodopsin. Ten years later Ham published a different action spectrum (in monkey) with highest susceptibility in the blue rather than the green. This spectrum was later also found in rat. In an attempt to find the unique conditions for each spectrum we gathered all monochromatic threshold data from the literature. Two sources adhered to the Noell type, 16 to the Ham type. An analysis of the conditions did not yield unique ones. © 2011 The American Society of Photobiology. Source

Van Strien M.E.,Institute of the Royal Netherlands Academy of science | Sluijs J.A.,Institute of the Royal Netherlands Academy of science | Reynolds B.A.,University of Florida | Steindler D.A.,University of Amsterdam | And 3 more authors.
Stem Cells Translational Medicine | Year: 2014

Neural progenitor cells (NPCs) in the subventricular zone (SVZ) hold promise for future therapy for neurodegenerative disorders, because the stimulation of adult neurogenesis could potentially restore the function of degenerating neurons and glia. To obtain more knowledge on these NPCs, we developed a method to specifically isolate NPCs from postmortem adult human brains based on the expression of the specific human adult neural stem/progenitor cell marker glial fibrillary acidic protein δ (GFAPδ). An extensive immunophenotyping analysis for cell surface markers resulted in the observation that CD271 was limited to the SVZ-derived GFAPδ-positive cells. CD271+ cells developed into neurospheres and could be differentiated into astrocytes, neurons, and oligodendrocytes. We are the first to show that a pure population of NPCs can be isolated from the adult human SVZ, which is highly instrumental for developing future therapies based on stimulating endogenous SVZ neurogenesis. © AlphaMed Press. Source

van den Berge S.A.,Institute of the Royal Netherlands Academy of science | Middeldorp J.,Institute of the Royal Netherlands Academy of science | Eleana Zhang C.,Institute of the Royal Netherlands Academy of science | Curtis M.A.,University of Auckland | And 7 more authors.
Aging Cell | Year: 2010

A main neurogenic niche in the adult human brain is the subventricular zone (SVZ). Recent data suggest that the progenitors that are born in the human SVZ migrate via the rostral migratory stream (RMS) towards the olfactory bulb (OB), similar to what has been observed in other mammals. A subpopulation of astrocytes in the SVZ specifically expresses an assembly-compromised isoform of the intermediate filament protein glial fibrillary acidic protein (GFAP-δ). To further define the phenotype of these GFAP-δ expressing cells and to determine whether these cells are present throughout the human subventricular neurogenic system, we analysed SVZ, RMS and OB sections of 14 aged brain donors (ages 74-93). GFAP-δ was expressed in the SVZ along the ventricle, in the RMS and in the OB. The GFAP-δ cells in the SVZ co-expressed the neural stem cell (NSC) marker nestin and the cell proliferation markers proliferating cell nuclear antigen (PCNA) and Mcm2. Furthermore, BrdU retention was found in GFAP-δ positive cells in the SVZ. In the RMS, GFAP-δ was expressed in the glial net surrounding the neuroblasts. In the OB, GFAP-δ positive cells co-expressed PCNA. We also showed that GFAP-δ cells are present in neurosphere cultures that were derived from SVZ precursors, isolated postmortem from four brain donors (ages 63-91). Taken together, our findings show that GFAP-δ is expressed in an astrocytic subpopulation in the SVZ, the RMS and the OB. Importantly, we provide the first evidence that GFAP-δ is specifically expressed in longterm quiescent cells in the human SVZ, which are reminiscent of NSCs. © 2010 The Authors Journal compilation © Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland 2010. Source

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