Showing papers in "Neurosignals in 2001"
01 May 2001-Neurosignals
TL;DR: The mitochondrion is the subcellular organelle affected earliest during the development of alcoholic liver disease, and hepatic mitochondria either acutely or chronically exposed to ethanol generate increased levels of reactive oxygen species (ROS), which is demonstrated in both isolated mitochondria and hepatocytes.
Abstract: The mitochondrion is the subcellular organelle affected earliest during the development of alcoholic liver disease. As a result of chronic ethanol consumption mitochondrial protein synthesis is decreased significantly due to a depression in the functioning of the mitochondrial ribosome. This causes a significant decrease in the concentrations of the thirteen mitochondria gene products, all of which are components of the oxidative phosphorylation system. Consequently, there is a depression in the rate at which ATP is synthesized in hepatic mitochondria. In addition to this loss in function, hepatic mitochondria either acutely or chronically exposed to ethanol generate increased levels of reactive oxygen species (ROS). This elevation in ROS has been demonstrated in both isolated mitochondria and hepatocytes. The increase in mitochondrial ROS production accompanying acute ethanol exposure is due to mitochondrial associated reoxidation of NADH produced during ethanol and acetaldehyde metabolism. The elevation in ROS generation observed in mitochondria from chronic ethanol consumers is likely due to decreases in mitochondrial-derived electron transport components, which in turn results in higher levels of the semiquinone forms of flavin mononucleotide and ubiquinone. Both these semiquinones readily donate electrons to molecular oxygen to form superoxide.
TL;DR: Melatonin receptors were studied in isolated mouse hepatocytes using the 2[125I]iodomelatonin binding assay, indicating that the binding was mediated by the ML1 receptor subtype and the linear Rosenthal plots, the close proximity of the Hill coefficient to unity and the monophasic competition curves suggest that a single class of 2[ 125I?]iodomelsatonin binding sites is present in the mouse hepatocyte.
Abstract: Melatonin receptors were studied in isolated mouse hepatocytes using the 2[125I]iodomelatonin binding assay. The binding of 2[125I]iodomelatonin to hepatocytes isolated from the
24 May 2001-Neurosignals
TL;DR: The idea that genetically damaged mitochondria accumulate with time and are causally responsible for the aging phenotype via a disturbed energy budget is at the core of the so called mitochondrial theory of aging.
Abstract: Mitochondria are not only the main source of energy for most eukaryotic cells, but also the main source of free radicals. These reactive molecules can damage all components of a cell such as membranes, proteins and DNA. Therefore they have long been suspected to be involved in the biological aging process. The fact that mitochondria posses their own genetic material (mtDNA) and that they only have a limited arsenal of DNA repair processes makes them one of the prime targets for reactive oxygen species. The idea that genetically damaged mitochondria accumulate with time and are causally responsible for the aging phenotype via a disturbed energy budget is at the core of the so called mitochondrial theory of aging. In recent years this idea has gained impetus from the discovery of mitochondrial diseases and mtDNA deletions in old organisms. However, there are still many open questions regarding the mechanism of the accumulation of these deletions and their physiological relevance. This review is therefore intended to give an overview of the current state of the mitochondrial theory of aging and to discuss some recent experimental findings.
TL;DR: A brief description of a search for a putative mVDR that lasted for over a decade is provided, which indicates that there are two mechanisms of the molecular mode-of-action of 1,25-dihydroxyvitamin D3.
Abstract: 1,25-Dihydroxyvitamin D3 is the hormonally active form of vitamin D3. Its involvement in regulation of calcium and phosphate homeostasis as well as in differentiation and regulat
01 May 2001-Neurosignals
TL;DR: The role of mitochondrial Ca2+ signaling in the control of cardiac apoptosis is concerned with the role of mitochondria play important role in the signaling machinery of apoptotic cell death.
Abstract: The broad significance of apoptosis in the cardiovascular system only began to be recognized more widely recently. Apoptotic cell death is a normal component of postnatal morphogenesis of the human ca
TL;DR: The results support the earlier concept and show for the first time that MEL can be transported from the mother to the young either prenatally through the placenta or postnatally via the milk in order to influence neonatal growth and sexual maturation.
Abstract: To date, the phenomenon of maternal transfer of hormones to the young is an enigma. The present study explains for the first time the maternal transfer of melatonin (MEL) to the young, affecting neona
TL;DR: It is suggested that melatonin levels may be affected in patients anaesthetized with halothane or ketamine, resulting in disturbed biological rhythms, especially the sleep-wake cycle following recovery.
Abstract: In mammals, the nocturnal rise in pineal melatonin is regulated by signals from the endogenous clock, the hypothalamic suprachiasmatic nuclei There have been few reports on whether anaesthetics which
28 Feb 2001-Neurosignals
TL;DR: The biogenesis of mitochondria requires the translocation of most mitochondrial proteins across two biological membranes through three large integral membrane protein complexes forming specialized preprotein translocases.
Abstract: The biogenesis of mitochondria requires the translocation of most mitochondrial proteins across two biological membranes. Mitochondrial preproteins are synthesized in the cytosol carrying targeting in
01 Nov 2001-Neurosignals
TL;DR: This appears to be the first demonstration of such categorical and prolonged potentials in a photoreceptor neuron, and suggests that efferent-driven neuromodulation can enable the development of a persisting short-term representation of a brief stimulus, with this representation being retained at the most distal possible neural site.
Abstract: Octopamine, a major efferent neurotransmitter in the lateral eye of the horseshoe crab (Limulus polyphemus) , has previously been shown to modulate photoreceptor responses evoked by
TL;DR: It is believed that PML functions as a stress-response gene in G8 cells rather than as a gene normally involved in regulating muscle development, as it significantly inhibited FGF-8b-stimulated cell proliferation and inhibited AP-1 and E-box transactivation.
Abstract: Muscle cell growth is regulated by growth-promoting and -inhibiting factors. In this study, the physiological effects of fibroblast growth factor (FGF)-8b and the promyelocytic leukemia (PML)
TL;DR: Neither PGF< sub>2α nor PGE2
Abstract: This study examined the effects of prostaglandin-F2α (PGF2α), prostaglandin-E2 (PGE2) and their interactions on progesterone production in human granulosa-l
TL;DR: The polysaccharide isolated from the capsule of Klebsiella pneumoniae serotype K24 was found to suppress the proliferation of Ehrlich ascites tumour cells in vitro, but did not alter the cell cycle distribution of cells.
Abstract: K24 capsular polysaccharide (K24-CPS), with a known structure of a repeating unit, was isolated from the capsule of Klebsiella pneumoniae serotype K24. The polysaccharide was found to suppress the proliferation of Ehrlich ascites tumour (EAT) cells in vitro, but did not alter the cell cycle distribution of cells. K24-CPS treatment reduced the tyrosine phosphorylation of some proteins in EAT cells. Furthermore, the treatment also decreased the expression of c-JUN, but had no effect on the levels of c-FOS and c-MYC. It is speculated that the growth suppression effect of K24-CPS may be related to its effect in down-regulating c-JUN expression.
TL;DR: This study examined how external cyclic nucleotides affect the light response mechanism of the pineal photoreceptors and explored the existence of parietal eye type of photoreceptor of which the internal cGMP concentration increased during the light responded, but does not indicate that the parietalEye type of Photoreceptor found in lizard participates in the chromatic and achromatic-type responses in the lamprey pineal organ.
Abstract: We examined in this study how external cyclic nucleotides affect the light response mechanism of the pineal photoreceptors and explored the existence of parietal eye type of photoreceptor of which the