Effects of dietary vitamin E and selenium on arginase activity in the liver, kidneys, and heart of rats treated with high doses of glucocorticoid

The effects of dietary intake of vitamin E and selenium on arginase activity in the liver, kidneys, and heart of rats treated with high doses of prednisolone were investigated. Rats were divided into five groups. Groups 3, 4, and 5 received a daily supplement in their drinking water of vitamin E, Se, and a combination of vitamin E and Se, respectively, for 30 days. For 3 days subsequently, the control group (group 1) was given a placebo, and the remaining four groups were injected intramuscularly with prednisolone. The tissue samples were collected from each group at 4, 8, 12, 24, and 48 h after the last administration of prednisolone. In the group treated with prednisolone alone, arginase activity in the liver was found to have increased at all the time periods, whereas it had decreased significantly in the heart at 48 h. Arginase activity in the kidneys was not affected by prednisolone. Compared to the control and prednisolone groups, arginase activity in the kidneys and heart of the vitamin E- and Se-supplemented groups was found to be significantly increased at all time periods, however, no difference was seen in the combination group. Arginase activity in the liver of the vitamin E-supplemented group was found to have decreased at all time periods, however, in the Se group compared to the prednisolone group it had reduced at 24 and 48 h only. In the combination group compared to the prednisolone group, liver arginase activity increased constantly up to 12 h returning to normal values at 48 h. Vitamin E and Se in combination may prevent the changes in arginase activity in various tissues caused by prednisolone.     

Influence of dietary selenium and vitamin E on the levels of fatty acids in brain and liver tissues of lambs

In this study, the effects of dietary vitamin E, selenium, and their combination on the levels of fatty acid composition of the brain and liver tissues were examined. In brain tissue, the amounts of most fatty acids increased in vitamin E, combination and selenium groups compared with control group values. While the proportions of myristic, pentadecanoic, palmitic, linoleic, and total saturated fatty acids were decreased in vitamin E, Se and combination groups, eicosapentaenoic, total unsaturated and MUFA were increased in the same groups. In addition, the proportions arachidonic, eicosapentaenoic, total unsaturated, ω6 and MUFA in the combination group were higher than in the control group. In liver tissue, the amounts of myristic, pentadecanoic, palmitic, eicosedienoic, eicosapentaenoic, docosahexaenoic, ω3 and PUFA were higher in the combination group than in the control group. Also the proportions of eicosapentaenoic, docosahexaenoic acids in supplemented groups were higher than those in the control group. We conclude that dietary vitamin E and selenium have an influence on the levels of fatty acids in the brain and liver. Copyright © 1999 John Wiley & Sons, Ltd.     

A Rat Brain Bicistronic Gene with an Internal Ribosome Entry Site Codes for a Phencyclidine-binding Protein with Cytotoxic Activity

The cloning and characterization of the gene for the fourth subunit of a glutamate-binding protein complex in rat brain synaptic membranes are described. The cloned rat brain cDNA contained two open reading frames (ORFs) encoding 8.9- (PRO1) and 9.5-kDa (PRO2) proteins. The cDNA sequence matched contiguous genomic DNA sequences in rat chromosome 17. Both ORFs were expressed within the structure of a single brain mRNA and antibodies against unique sequences in PRO1- and PRO2-labeled brain neurons in situ, indicative of bicistronic gene expression. Dicistronic vectors in which ORF1 and ORF2 were substituted by either two different fluorescent proteins or two luciferases indicated concurrent, yet independent translation of the two ORFs. Transfection with noncapped mRNA led to cap-independent translation of only ORF2 through an internal ribosome entry sequence preceding ORF2. In vitro or cell expression of the cloned cDNA led to the formation of multimeric protein complexes containing both PRO1 and PRO2. These complexes had low affinity (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801)-sensitive phencyclidine-binding sites. Overexpression of PRO1 and PRO2 in CHO cells, but not neuroblastoma cells, caused cell death within 24–48 h. The cytotoxicity was blocked by concurrent treatment with MK-801 or by two tetrahydroisoquinolines that bind to phencyclidine sites in neuronal membranes. Co-expression of two of the other subunits of the protein complex together with PRO1/PRO2 abrogated the cytotoxic effect without altering PRO1/PRO2 protein levels. Thus, this rare mammalian bicistronic gene coded for two tightly interacting brain proteins forming a low affinity phencyclidine-binding entity in a synaptic membrane complex.A complex of four proteins purified from brain synaptic membranes was shown to have recognition sites for l-glutamate, N-methyl-d-aspartate (NMDA),⁴ and other ligands characteristic of NMDA receptors in brain, including binding sites for the co-agonist glycine, the modulator spermine, the competitive antagonist (+)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP), and the ion channel inhibitors thienylcyclohexylpiperidine (TCP) and (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) (1, 2). Reconstitution of the purified complex into planar lipid bilayer membranes leads to the formation of channels with four ion conductance levels upon activation by glutamate or NMDA in the presence of glycine (3). These conductances differ from either the predominant NMDA-activated receptor-ion channels of brain neurons or those formed by reconstitution of the NMDA receptor subunits (4), but are similar to those described for ion channels in rat spinal cord motor neurons (5).The genes for three of the proteins in this complex have been cloned and expressed in heterologous cells (6–10). The gene GRINA for the glutamate-binding protein (GBP) subunit was identified as part of a “learning and memory” module of genes expressed in the entorhinal cortex of the mammalian brain (11), and as the gene responsible for mental retardation and epilepsy in infants with a gene duplication in chromosome 8q24.3 (12). Expression of GRINA in heterologous cells leads to activation of mitogen-activated protein kinases (13), i.e. it may be involved in signal transduction in neurons. Because of the potential role of GBP and of the associated membrane complex in cell signaling, there is a need to fully characterize all components of the complex and reconstitute the intact complex in cells lacking in its expression. The genes for two other components of the complex have been cloned, those for the glycine-binding and CPP-binding proteins. But the gene for the fourth subunit has not yet been cloned.The fourth protein of the complex was identified on SDS-PAGE as an ∼40-kDa protein. To complete the characterization of this complex of proteins, the cDNA for the fourth subunit was cloned, and a corresponding genomic sequence in rat genome was identified. The presence of two open reading frames (ORFs) in the cloned cDNA, the expression of both ORFs in a single mRNA in brain, and the translation in brain of the two proteins coded by the cDNA, led to the investigation of the mechanism of translation of both ORFs. Translation of both ORFs through an internal ribosome entry sequence (IRES) was identified, as was the need for the co-expression of the two proteins to create a functional protein, a phencyclidine-binding protein.     

Arachidonic acid metabolites and colchicine in Beh?et's disease (BD)

Vasculitis is accepted to be the basis of Beh?et's disease (BD) which is a multisystem disease, and the arachidonic acid(AA) metabolites acting as balancing mediators in the organism are accepted to be responsible for the vasculitis. In this study, we examined the prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) levels of the patients with BD before and after colchicine therapy. We found a statistical decrease in the PGE2 and LTC4 levels after colchicine therapy compared to the previous levels, concluding that colchicine inhibits the inflammation and the polymorphonuclear leukocyte (PML) chemotaxis by inhibiting the cyclooxygenase and lipoxygenase pathways.     

Nobiletin attenuates acetaminophen‐induced hepatorenal toxicity in rats

The study aimed to examine the effects of nobiletin on the toxicity model induced with acetaminophen (APAP). For this purpose, 24 adult male rats were equally divided into four groups. The groups were the control group (group 1); dimethyl sulfoxide only, the APAP group (group 2) received a single dose of APAP 1000 mg/kg on the 10th day of experiment; the Nobiletin group (group 3), nobiletin (10 mg/kg) for 10 days; and the APAP + Nobiletin group (group 4), nobiletin (10 mg/kg) for 10 days with a single dose of APAP (1000 mg/kg) administered on the 10th day and the experiment ended after 48 hours. At the end of the study, a significant increase in malondialdehyde, interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6), and tumor necrosis factor‐α (TNF‐α) levels and a significant decrease in glutathione levels, glutathione peroxidase activities and nuclear factor erythroid‐derived 2‐like 2 (Nrf‐2) and heme oxygenase‐1 (HO‐1) expressions were observed with APAP application in liver and kidney tissues. Serum aspartate transaminase (AST), alanine transaminase (ALT), urea, and creatinine levels were also significantly increased in the APAP group. However, nobiletin treatment in group 4 reversed oxidative stress and inflammatory and histopathological signs caused by APAP. It is concluded that nobiletin may be a beneficial substance that confers hepatorenal protection to APAP‐induced toxicity via antioxidant and anti‐inflammatory mechanisms.     

Effects of dietary vitamin E and selenium on antioxidative defense mechanisms in the liver of rats treated with high doses of glucocorticoid

The aim of this work was to determine the effects of dietary intake vitamin E and selenium (Se) on lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and on the antioxidative defense mechanisms in the liver of rats treated with high doses of prednisolone. Two hundred fifty adult male Wistar rats were randomly divided into five groups. The rats were fed a normal diet, but groups 3, 4, and 5 received a daily supplement in their drinking water of 20 mg vitamin E, 0.3 mg Se, and a combination of vitamin E and Se, respectively, for 30 d. For 3 d subsequently, the control group (group 1) was treated with a placebo, and the remaining four groups were injected intramuscularly with 100 mg/kg body weight (BW) prednisolone. After the last administration of prednisolone, 10 rats from each group were killed at 4, 8, 12, 24, and 48 h and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) enzymes and the levels of glutathione (GSH) and TBARS in their livers were measured. GSH-Px, SOD, and CAT enzyme activities and GSH levels in prednisolone-treatment group (group 2) began to decrease gradually at 4 h, falling respectively to 38%, 55%, and 40% of the control levels by 24 h, and recovering to the control levels at 48 h. In contrast, prednisolone administration caused an increase in the hepatic TBARS, reaching up to four times the levels of the control at 24 h. However, supplementation with vitamin E and Se had a preventive effect on the elevation of the hepatic TBARS and improved the diminished activities of the antioxidative enzymes and the levels of GSH. Therefore, the present study demonstrates the effectiveness of vitamin E and Se in reducing hepatic damage in glucocorticoid-treated rats and suggests that reductions in increased TBARS as a result of prednisolone may be an important factor in the action of vitamin E and Se.     

Structure and function of an early divergent form of laminin in hydra: a structurally conserved ECM component that is essential for epithelial morphogenesis

As a major component of the extracellular matrix (ECM), laminin has been found in many vertebrate and invertebrate organisms. Its molecular structure is very similar across species lines and its biological function in the ECM has been extensively studied. In an effort to study ECM structure and function in hydra, we have cloned a partial hydra laminin alpha chain and the full-length hydra laminin beta chain using ECM-enriched cDNA libraries. Analysis of deduced amino acid sequences indicated that both polypeptides have high sequence similarity to a number of invertebrate and vertebrate laminin alpha and beta subunits. Rotary shadow analysis of isolated hydra laminin indicates it has a heterotrimeric organization that is characteristic of vertebrate laminins. A putative integrin-class protein was also identified using a cell-binding peptide sequence from the laminin beta chain as an affinity probe, indicating that integrins are possible cell surface receptors in hydra. In agreement with previous results for the hydra laminin beta chain, in situ hybridization experiments revealed that hydra laminin alpha chain mRNA is restricted to endodermal cells. As with a number of other hydra ECM components, higher levels of laminin alpha chain mRNA are localized to regions where cell migration and differentiation are actively undertaken such as the base of tentacles, the peduncle region, buds, regenerating tentacles, and at the head end during regeneration. The role of laminin in morphogenesis was studied using an antisense approach and the results indicated that translation of the laminin alpha chain is required for head regeneration.     

Blood plasma levels of lipoperoxides,glutathione peroxidase,beta carotene,vitamin A and E in women with habitual abortion

The plasma levels of lipoperoxides, glutathione peroxidase (GSH-Px), reduced glutathione (GSH), beta carotene, vitamin A, E, some plasma biochemical and blood haematological parameters were investigated in 40 women with habitual abortion (HA) and controls. The levels of GSH, vitamin A, E and beta carotene were significantly lower in women with HA than in controls. However, the plasma levels of lipid peroxidation, alkaline phosphatase (ALP), glucose and blood haemoglobin were significantly higher in HA than in controls. In addition, plasma levels of GSH-Px, AST, ALT, total bilirubin, total protein, albumin, sodium, potassium, calcium and number of white blood cells, red blood cells, platelet and values of packet cell volume showed no significant differences between HA and controls. According to the results of this study, we observed that the levels of lipid peroxidation were increased and plasma levels of vitamin A, E and beta carotene were decreased in HA. The decrease of those antioxidants may play a significant role in women with habitual abortion. Copyright © 1998 John Wiley & Sons, Ltd.     

Influence of Cobalt and Zinc Exposure on mRNA Expression Profiles of Metallothionein and Cytocrome P450 in Rainbow Trout

The present research aims to evaluate the effects of cobalt and zinc exposure of rainbow trout (Oncorhynchus mykiss) on metallothioneins and cytocrome P450. Mature rainbow trouts were exposed to 10?mg/L CoCl(2).6H(2)O and 1?mg/L ZnSO(4).7H(2)O. After 6, 12, 24, and 48?h of treatment, expressions of muscle MT-A, MT-B, and CYP P4501A1 mRNAs were measured by means of quantitative real-time polymerase chain reaction. During the exposure experiments, no mortalities occurred. We observed that expression levels of all genes increased with exposure time. Since the organism has not learned how to completely dispose of heavy metals and tends to bioaccumulate them, our results indicate that cobalt and zinc exposure may result in accumulation of the non-eliminated metals which may lead to fish death.