Response analysis of vertebrate retina

In a recent work (Ouztöreli, 1980) a mathematical model for studying the neural activities in a vertebrate retina has been investigated, where the basic network contains five interconnected neurons: a receptor cell, a bipolar cell, a horizontal cell, an amacrine cell, and a retinal ganglion cell. More recently, in (Ouztöreli and O'Mara, 1980) the basic network has been extended to a larger network containing twelve neurons. In both of these works, the performances of the basic and extended models were discussed under different structural and processing conditions with constant inputs by using the results of one of our earlier work (Ouztöreli, 1979). In the present paper we investigate by simulations the responses of the basic retinal network to piecewise constant and periodic inputs. The step and frequency responses of the extended retinal network will be discussed in a forthcoming paper.This work was partially supported by the Natural Sciences and Engineering Research Council of Canada under Grant A-4345 through the University of alberta     

Identification of a novel IVD mutation in a consanguineous family with isovaleric acidemia

Isovaleric acidemia (IVA) is a rare autosomal recessive disorder caused by a deficiency of isovaleryl-CoA dehydrogenase encoded by IVD gene. In this case study we report the first Saudi IVA patients from a consanguineous family with a novel transversion (p.G362V) and briefly discuss likely phenotype–genotype correlation of the disease in the Saudi population. We explored the functional consequences of the mutation by using various bioinformatics prediction algorithms and discussed the likely mechanism of the disease caused by the mutation.     

Calorie restriction modulates hippocampal NMDA receptors in diet-induced obese rats

Calorie restriction (CR) has attracted increased interest since CR enhances lifespan and alters age-related decline in hippocampal-dependent cognitive functions. Obesity is associated with poor neurocognitive outcome including impaired hippocampal synaptic plasticity and cognitive abilities such as learning and memory. N-Methyl-D-aspartate receptors (NMDARs) are linked to hippocampal-dependent learning and memory, which may be stabilized by CR. In the present study, we aimed to establish the effects of CR on NMDARs in CA1 region of hippocampus in obese and non-obese rats. In addition, malondialdehyde (MDA) levels were determined as a marker for lipid peroxidation (LPO) in hippocampus. Four groups were constituted as control group (C, n?=?9), obese group (OB, n?=?10), obese calorie-restricted group (OCR, n?=?9), and non-obese calorie-restricted group (NCR, n?=?10). OCR and NCR were fed with a 60% CR diet for 10 weeks. After 10 weeks of CR, the MDA levels significantly decreased in the calorie-restricted groups. Obesity caused significant decreases in NR2A and NR2B subunit expressions in the hippocampus. The hippocampal NR2A and NR2B levels significantly increased in the OCR group compared with the OB group (P?相似文献   

Agricultural recovery of a formerly radioactive area: II. Systematic proteomic characterization of flax seed development in the remediated Chernobyl area

Molecular characterization of crop plants grown in remediated, formerly radioactive, areas could establish a framework for future agricultural use of these areas. Recently, we have established a quantitative reference map for mature flax seed proteins (Linum usitatissimum L.) harvested from a remediated plot in Chernobyl town. Herein we describe results from our ongoing studies of this subject, and provide a proteomics-based characterization of developing flax seeds harvested from same field. A quantitative approach, based on 2-dimensional electrophoresis (2-DE) and tandem mass spectrometry, yielded expression profiles for 379 2-DE spots through seed development. Despite the paucity of genomic resources for flax, the identity for 102 proteins was reliably determined. These proteins were sorted into 11 metabolic functional classes. Proteins of unknown function comprise the largest group, and displayed a pattern of decreased abundance throughout seed development. Analysis of the composite expression profiles for metabolic protein classes revealed specific expression patterns during seed development. For example, there was an overall decrease in abundance of the glycolytic enzymes during seed development.     

The effects of isoniazid on hippocampal NMDA receptors: Protective role of Erdosteine

Isoniazid (INH) has neurotoxic effects such as seizure, poor concentration, subtle reduction in memory, anxiety, depression and psychosis. INH-induced toxic effects are thought to be through increased oxidative stress, and these effects have been shown to be prevented by antioxidant therapies in various organs. Increased oxidative stress may be playing a role in these neurotoxic effects. N-methyl D-aspartat receptors (NMDA) are a member of the ionotropic group of glutamate receptors. These receptors are involved in a wide variety of processes in the central nervous system including synaptogenesis, synaptic plasticity, memory and learning. Erdosteine is a potent antioxidant and mucolytic agent. We aimed to investigate adverse effects of INH on rat hippocampal NMDAR receptors, and to elucidate whether erdosteine prevents possible adverse effects of INH. In the present study, compared to control group, NMDAR2A (NR2A) receptors were significantly decreased and malondialdehyde (MDA), end product of lipid peroxidation, production was significantly increased in INH-treated group. On the other hand, administration of erdosteine to INH-treated group significantly increased NR2A receptors and decreased MDA production. In conclusion, decreasing NR2A receptors in hippocampus and increasing lipid peroxidation correlates with the degree of oxidative effects of INH and erdosteine protects above effect of INH on NR2A receptors and membrane damage due to lipid peroxidation by its antioxidant properties.     

The effects of subchronic methidathion toxicity on rat liver: Role of antioxidant vitamins C and E

Methidathion (MD) phosphorodithioic acid S-[(5-methoxy-2-oxo-1,3,4-thiadiazol-3(2H)-yl)methyl] O,O-dimethyl ester is the organophosphate insecticide (OPI) most commonly used worldwide in the pest control of crops. Subchronic MD exposure was evaluated for its effects on lipid peroxidation, the serum activities of cholinesterase (ChE), and enzymes concerning liver damage, and the protective effects of combination of vitamins E and C in albino rats. Additionally, the histopathological changes in liver tissue were examined. Experimental groups were as follows: control group; a group treated with 5 mg/kg body weight MD (MD group); and a group treated with 5 mg/kg body wight MD plus vitamin E plus vitamin C (MD+AO group). The MD and MD+AO groups were treated orally with MD on five days a week for 4 weeks. The serum activities of cholinesterase (ChE), alanine transferase (ALT), aspartate amiotransferase (AST), lactate dehydrogenase (LDH), γ-glutamyltransferase (GGT), alkaline phosphatase (ALP), and the concentration of malondialdehyde (MDA) and liver histopathology were studied. In serum samples, MD significantly increased MDA concentration and ALP, AST, GGT, LDH activities but decreased the ALT and ChE activities. In the MD+AO group, MDA level and ALP, AST, LDH activities were significantly decreased and ChE activity was increased compared to the MD group. Histopathological changes found in liver tissue of rats treated with MD included were infiltration with mononuclear cells in all portal areas, sinusoidal dilatation, and focal microvesicular steatosis and hydropic degenerations in parenchymal tissue. The severity of these lesions was reduced by administration of vitamins. From these results, it can be concluded that subchronic MD causes liver damage, and lipid peroxidation may be a molecular mechanism involved in MD-induced toxicity. Furthermore, the combination of vitamins E and C can reduce the toxic effects of MD on liver tissue of rats.     

Comparative evaluation of western blotting in hepatic and pulmonary cystic echinococcosis

Many serological tests are widely used in the diagnosis of cystic echinococcosis (CE), caused by the larval stages of Echinococcus granulosus. The present study was carried for differentiation between hepatic and pulmonary cystic echinococcosis by Western Blotting (WB). A total of 121 sera from patients with hepatic CE (37), pulmonary CE (31) and controls (53; consisting of six healthy, seven Hymenolepis nana infection, 20 hepatic and 20 pulmonary diseases other than CE) were examined. In all of the CE patients, E. gronulosus infection was confirmed by surgical intervention. Sera were previously tested using IHA and ELISA to detect the E. gronulosus specific antibodies. Sera from hepatic cases of CE reacted with 16 polypeptides of 6-116 kDa and sera from pulmonary cases of CE reacted with 14 polypeptides of 4-130 kDa by Western Blotting. The WB test enabled the detection of antibodies in the hepatic CE samples for proteins of 24, 32 34, 44-46 and 52-54 kDa in molecular weight in 78.4%, 75.7%, 78.4% and 89.2% of the patients, respectively. In the pulmonary CE samples sera WB test enabled the detection of antibodies 24, 44-46, 100, 110, 116 and 120 124 kDa in molecular weight in 81.3%, 75.0%, 87.5%, 71.9%, 84.4% and 65.6% of the patients, respectively. We indicated that the antigenic components of high molecular weight can be good candidates for differentiation of hepatic CE from pulmonary CE.