Molecular Genetic Pathogenesis

For many years, RS was thought to be a result of a defect in the Muller cell that acted as a cellular scaffold within the retinal architecture. Recent studies on gene expression and immunolocalization of retinoschisin indicate that it is expressed in all major classes of adult retinal neural cells, with the possible exception of horizontal cells, and that there is no retinoschisin detected in Muller cells or processes,[22] although this is reported by others.[33,34] RS! is abundantly expressed in the inner segments of photo-receptors in human and mouse eye sections.[21,22,32] The exact cause of the retinal separation in RS is not known. To address this and understand the pathological basis of RS, Wang et al.[35] conducted in vitro experiments and reported that the cause of RS is due to intracellular retention of the majority of mutant proteins. The phenotype may depend on the secretory capacity of the cells and the degree to which they may induce the unfolded protein response. Another study showed that misfolding of the discoidin domain, defective disulfide-linked subunit assembly, and inability of retinoschisin to insert into the endoplasmic reticulum membrane as part of the protein secretion process are all responsible for the loss in function of retinoschisin as a cell adhesion protein and lead to the development of RS.[36] Other investigators suggest that the mutant retinoschisin may be functionally defective leading to schisis formation.[32,37] A study of retinoschisin during development of the mouse retina showed that retinal ganglion cells are the first to express RS protein, by postnatal day P1; RS expression subsequently occurs in posterior retinal layers over a 14-day developmental period, indicating the presumptively important role of this protein in early eye development.1-22-1

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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