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showing 10 items of 384 documents
Electron microscopic localization of nitric oxide I synthase in the organ of Corti of the guinea pig
1997
Nitric oxide synthase (NOS) activity has been detected previously in the mammalian cochlea at a light microscopic level. Here we present results of electron microscopic analysis for post-embedding immunoreactivity of neural-type NOS I in the cochlea of the guinea pig. Strong enzyme immunoreactivity was identified in the cytoplasm of inner and outer hair cells. Gold-labeled NOS I antibodies were mainly located in electron-dense areas of the cytoplasm, whereas electron-lucent regions of the receptor cells were nearly free from any immunoreactivity. In both types of hair cells anti-NOS I antibodies were also visible in the cuticular plates, hair bundles and nuclei. Further ultrastructural anal…
Cadmium and mitochondria
2009
The heavy metal cadmium (Cd) a pollutant associated with several modern industrial processes, is absorbed in significant quantities from cigarette smoke, water, food and air contaminations. It is known to have numerous undesirable effects on health in both experimental animals and humans, targeting kidney, liver and vascular system. The molecular mechanism accounting for most of the biological effects of Cd are not well-understood and the toxicity targets are largely unidentified. The present review focuses on important recent advances about the effects of cadmium on mitochondria of mammalian cells. Mitochondria are the proverbial powerhouses of the cell, running the fundamental biochemical…
Neurosteroidogenesis in Rat Retinas
2002
Neurosteroids (steroids synthesized in the CNS) function by modulating neurotransmission. To establish an experimental model for investigation of neurosteroid synthesis and regulation, independent of blood-borne steroids, we examined the steroidogenic activity of isolated rat retinas. We identified progesterone, pregnenolone, dehydroepiandrosterone, desoxycorticosterone, 3 alpha,5 alpha-tetrahydrodesoxycorticosterone, 3 alpha-hydroxy-5 alpha-dihydroprogesterone, 17-hydroxyprogesterone, and 17-hydroxypregnenolone together with their esterified forms. As pregnenolone is the precursor of all steroids, its formation was studied in detail as an index of a steroid-synthesizing tissue. Pregnenolon…
High levels of exogenous C2-ceramide promote morphological and biochemical evidences of necrotic features in thyroid follicular cells
2002
CD95 and ceramide are known to be involved in the apoptotic mechanism. The triggering of CD95 induces a cascade of metabolic events that progressively and dramatically modifies the cell shape by intense membrane blebbing, leading to apoptotic bodies production. Although the CD95 pathway has been abundantly described in normal thyrocytes, the effects of cell permeable synthetic ceramide at morphological and biochemical levels are not fully known. In the present study, we show that thyroid follicular cells (TFC) exposed to 20 microM of C(2)-ceramide for 4 h are characterized by morphological features of necrosis, such as electron-lucent cytoplasm, mitochondrial swelling, and loss of plasma me…
Delayed postnatal neurogenesis in the cerebral cortex of lizards
1988
Labelled cells were consistently observed in the medial cortex of the lizard brain after i.p. injections of tritiated thymidine (5 microCi/g b. wt.), 1, 7, 18 or 28 days of survival and posterior autoradiographic evaluation. In 3 groups of specimens (postnatal, young and adult) of the species Podarcis hispanica, after one day of survival, labelled cells were located in the ependymal cell layer underlying the medial cortex. After intermediate survival times (7, 18 days), labelled cells were found in 3 zones: the ependymal layer, the inner plexiform layer and the granular layer. After one month of survival, most labelled cells were observed in the granular layer. In the granular layer, these …
Postnatal neurogenesis in the medial cortex of the tropical lizard Tropidurus hispidus.
2004
Young, adult and presumed old specimens of the tropical lizard Tropidurus hispidus, living in an almost steady warm habitat, have been the subjects of a 5-bromodeoxiuridine immunocytochemical study to label proliferating brain cells. All animals showed abundant 5-bromodeoxiuridine-labeled nuclei in the ependyma of their telencephalic lateral ventricles, with these being especially abundant in the medial cortex ependyma. Surprisingly, adult animals displayed higher numbers of labeled nuclei when compared with those of young specimens. In a second experiment, in order to check the evolution of ependymal-labeled nuclei, adult specimens were allowed 4 h or 2, 4, 7, 15 or 30 days of survival aft…
Long-spined polymorphic neurons of the medial cortex of lizards: a Golgi, Timm, and electron-microscopic study.
1988
The morphology, ultrastructure, and principal synaptic input of longspined neurons located in the inner plexiform layer of the medial cortex in three related species of lizards is described. Golgi impregnations have been used to define the external morphology of these neurons and their axonal trajectories. Their most striking characteristic is the presence of very long spines or “microdendrites” especially abundant on the distal dendritic segments. Axons have ascendent trajectories, pass through the cell layer, and ramify in the outer plexiform layer. Combined Golgi-electron microscopy as well as standard electron microscopy permitted the definition of the ultrastructure of these neurons. T…
Ontogeny of somatostatin immunoreactive neurons in the medial cerebral cortex and other cortical areas of the lizardPodarcis hispanica
1996
The ontogeny of somatostatin immunoreactive interneurons in the cerebral cortex of the lizard Podarcis hispanica has been studied in histological series of embryos, perinatal specimens, and adults. Somatostatin immunoreactive interneurons appear in the early stages of lizard cerebral cortex ontogeny, their number increases during embryonary development, reaches a peak in early postnatal life, and decreases in adult lizards. The first somatostatin immunoreactive somata in the lizard forebrain appeared on E36, and they were located in non cortical areas. Then, on E39 and later, somatostatin immunoreactive neurons were seen in the lizard cortex in a rostral-to-caudal spatial gradient, which pa…
Initial Radical Cation Pathway in the Mo2Cl10-Mediated Dehydrogenative Arene Coupling
2015
Experimental (EPR) and theoretical (DFT) evidence is provided for radical cation formation as initial step in the Mo2Cl10-mediated dehydrogenative arene coupling. The initial electron transfer from methoxyarenes to molybdenum proceeds via an inner sphere mechanism.
The inner nuclear membrane protein Src1 associates with subtelomeric genes and alters their regulated gene expression
2008
Inner nuclear membrane proteins containing a LEM (LAP2, emerin, and MAN1) domain participate in different processes, including chromatin organization, gene expression, and nuclear envelope biogenesis. In this study, we identify a robust genetic interaction between transcription export (TREX) factors and yeast Src1, an integral inner nuclear membrane protein that is homologous to vertebrate LEM2. DNA macroarray analysis revealed that the expression of the phosphate-regulated genes PHO11, PHO12, and PHO84 is up-regulated in src1Δ cells. Notably, these PHO genes are located in subtelomeric regions of chromatin and exhibit a perinuclear location in vivo. Src1 spans the nuclear membrane twice an…