Morphologic Evaluation of Cat Corneal Endothelium Preserved in Korean Corneal Storage Medium

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Cell Death and Cell Proliferation during Histogenesis in the Rat Retina after Birth / 대한해부학회지

During development of central nervous system, cell proliferation, cell migration, cell differentiation and cell death are required. It has been reported that a number of cells are dying during development in the mammalian retinae examined so far, but the pattern of cell death has not been clarified yet. In addition. little has been studied on cell proliferation after birth. This study was conducted to identify histogenesis, cell death and cell proliferation in the retinae of the developing rats by light and electron microscopic methods as well as by immunohistochemical method using anti-proliferating cell nuclear antigen [PCNA] antiserum. The results were as follows : 1. In the developing rat, from postnatal 0 through 7 days, retina consisted of ganglion cell layer, inner plexiform layer and neuroblast layer. Neuroblast layer could be subdivided into three sublaminae : sublamina a, sublamina b and sublamina p, from postnatal 3 through 7 days. 2. From postnatal 10 days, retina consisted of ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer and outer nuclear layer. 3. Cells undergoing degeneration were observed from postnatal 0 to 13 days, and patterns of cell death were apoptosis, cytoplasmic degeneration and autophagic degeneration. 4. PCNA-immunoreactivity was seen in the cells located in sublaminae b and p of the neuroblast layer at postnatal 0 and 1 days. From postnatal 3 days PCNA immunoreactivity decreased. At 7-day-old rat, PCNA-Immunoreactive cells scattered in the distal part of sublamina p of the neuroblast layer.No immunoreactivity was observed from postnatal 10 days. These results demonstrate that retinal cell proliferation ends at postnatal 7 days, and histogenesis of retina is completed at postnatal 10 days, and superfluous cells during retinal development are eliminated by apoptosis, cytoplasmic degeneration and autophagic degeneration.

Immunocytochemical Study of Calcium Binding Protein in the Distal Nephron of Rat Kidney / 대한해부학회지

Calbindin-D28k, a vitamin D-dependent calcium binding protein, plays a cardinal role in transport of calcium in kidney. Previous studies have demonstrated calbindin-D28k immunoreactivity in the distal nephron of mammalian kidney. However, it is well known that in most species including rat and human, there is a gradual transition from the distal convoluted tubule to the cortical collecting duct, and that the connecting segment do no tclearly demarcated, because of intermingling of distal convoluted tubule cells, connecting tubule cells, principal cells and at least two configurations of intercalated cells. In this study, to identify the cell types of calbindin-D28k-positive cells in distal nephron of rat kidney, we used double immunostaining with an antibody against calbindin-D28k and antibodies against thiazide sensitive Na+/Cl- cotransporter for distal convoluted tubule or H+-ATPase for intercalated cells. In the distal convoluted tubule, most of the distal convoluted tuble cells were calbindin-D28k-positive, whereas the intercalated cells were calbindin-D28k-negative. In the connecting tubule, 68% of the cells were calbindin-D28k-positive, and about 97% of the positive cells were connecting tubule cells and only 3% of them were intercalated cells. In the cortical collecting duct, and outer medullary collecting duct of outer stripe and inner stripe, only 8.6%, 11.8% and 4.4% of cells were weak positive for calbindin-D28k respectively. These weak positive cells in the collecting duct are mainly identified as intercalated cells. These findings indicate that calbindin-D28k is involved in not only transcellular transport of calcium but also processes regulating intracellular calcium in rat kidney.

Colocalization of GABA and Glycine within the Neurons of the Rat Retina / 대한해부학회지

The role of GABA or glycine as an inhibitory neurotransmitter is well established, and GABAergic or glycinergic neurons appear to play an important role in the mammalian retinas. It has been reported that certain amacrine, bipolar, displaced amacrine and ganglion cells are consistently labeled with anti-GABA or anti-glycine antisera in the mammalian retinae so far, and it has been suggested that colocalization of GABA and glycine within the retinal neurons could be common in the mammalian retina by recent immunecytochemical and electrophysiological studies. This study was conducted to localize GABAergic and glycinergic neurons and to define whether GABA and glycine are colocalized within same retinal neurons of the rat retina by immunocytochemical method using anti-GABA and anti-glycine antisera. The results were as follows : 1. GABAergic neurons of the rat retina were amacrine, interplexiform, bipolar, displaced amacrine and ganglion cells, and processes of GABAergic neurons formed dense networks with distinct two bands in the inner plexiform layer. 2. Glycinergic neurons were amacrine, bipolar, displaced amacrine and ganglion cells,and their processes were evenly distributed as dense networks through whole inner plexiform layer. 3. 28.5% of GABA immunoreactive amacrine cells and 9.8% of GABA immunoreactive bipolar cells located in the inner nuclear layer,and 11.9% of labeled neurons located in the ganglion cell layer showed glycine immunoreactivity in the rat retina. These results demonstrate that GABA and glycine, major inhibitory neurotransmitters, are colocalized within certain amacrine and displaced amacrine cells, and a few bipolar cells, and that neurons synthesizing and utilizing both GABA and glycine as their neurotransmitters may play an unique role in the visual processing in the rat retina.