Spontaneous tone in deoxycorticosterone acetate-salt hypertensive rats

This body of work tests the hypothesis that reactive oxygen species (ROS) contribute to the modulation of spontaneous tone observed in aortic rings from deoxycorticosterone acetate (DOCA) salt hypertensive rats. In isolated organ baths, tension developed in rings from hypertensive but not SHAM-normotensive rats in response to increases in preload. Endothelial-denudation and nitric oxide (NO) synthase inhibition with NG-nitro-L arginine methyl ester (L-NAME) increased spontaneous tone. These results indicate that spontaneous tone is related to the preload and that NO plays a protective role opposing tone. Basal superoxide anion (02.-) production was increased in aortic rings from DOCA-salt hypertensive rats. Stretch increased 02.- production even further. Tempol, an 02.- scavenger, or apocynin, an inhibitor of NADPH-oxidase, attenuated hypertension. Spontaneous tone was abolished by superoxide dismutase (SOD), tempol, or apocynin in endothelium-intact rings but not in endothelium-denuded rings nor in L-NAME treated rings. Catalase, the enzyme that breaks down hydrogen peroxide (H202), increased spontaneous tone. Taken together, these findings suggest that O2.- derived from NAD(P)H-oxidase modulates spontaneous tone primarily by scavenging NO, while H202 serves as a protective mechanism. The cyclooxygenase (COX) inhibitor, valeroyl salicylate, and the thromboxane-prostaglandin (TP) receptor antagonist, SQ 29548, inhibited spontaneous tone. 20-hydroxyeicosatetraenoic acid (20-HETE) production was increased in rings from DOCA-salt hypertensive rats. Inhibition of the CYP4A isozyme with aminobenzotriazole decreased spontaneous tone. Exogenous 20-HETE increased spontaneous tone in an endothelium-dependent manner. These effects were blocked by the COX inhibitor or the TP-receptor antagonist. Thus 20 HETE increases tone, an effect likely mediated by its COX metabolites. Cromakalim, a KATP channel opener, abolished spontaneous tone in a glibenclamide-sensitive fashion. In aortic cells from DOCA-salt hypertensive rats, ATP-dependent K+(KATP) channel currents were either absent or weak in response to challenges by elevated extracellular K+ and by cromokalim. These findings suggest that the function of KATP channels is impaired in smooth muscle cells from aorta of DOCA-salt hypertensive rats. The data support the hypothesis that a complex array of ROS and metabolites of arachidonic acid (20-HETE and its metabolites) interact in concert with depressed KATP channel activity to modulate spontaneous tone in the DOCA-salt model

Utilization of Acacia auriculiformis seed (Akashmoni) oil – A new source for the synthesis of alkyd resin

717-723An alkyd resin is prepared from a renewable raw material Acacia auriculiformis seed oil (ASO), which has a high content of linoleic acid. Long oil alkyd resins have been synthesized by alcoholysis followed by the poly-esterification method using oil, glycerol, pentaerythritol (PE), sorbitol, phthalic anhydride (PA), and maleic anhydride (MA) in proportions according to alkyd formula calculation. The various physicochemical properties of ASO like acid value, saponification value, iodine value, etc, and fatty acid composition were determined. Physico-chemical properties of alkyd resins like viscosity, acid value, nonvolatile matter, etc. were determined and compared with soybean oil-based alkyd resins. The structural characterization of the resins was carried out using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopic techniques. These resins were cured by drier and their film properties were determined. The drying properties of the alkyd resins had been improved remarkably in the case of ASO-based resin. The performance of coating film produced by these alkyd resins were characterized by drying time, gloss measurement, hardness test, cross-cut adhesion test, and chemical resistance test. Analysis of these alkyds proved that ASO can be used as a new potential raw material for surface coating application

Protective role of Ipomoea aquatica Forsk. crude extract on rat tissues in the presence of acephate and carbofuran by histopathology and cytometric determination

118-124Ipomoea aquatica Forsk., commonly called water spinach ( ‘kalmi’ in Bengali) is an underexploited local green leafy vegetable having enormous scope as a cheap antioxidant source. The study explores the ameliorative effect of aqueous I. aquatica extract (IAE) in acephate and carbofuran treated Wistar male rats. Aqueous IAE (@ 20 mg/kg body wt.), administered to rats treated with organophosphate acephate (@ 30 mg/kg body wt.) and carbamate carbofuran (@ 0.1 mg /kg body wt.), attenuated the cholinesterase activity in brain, liver and cellular blood and reformed the histological perturbations in the brain cortex as well as the kidney anomalies, to a good extent. The IAE also upregulated the NF-E2-related factor-2 (Nrf-2) and MnSOD gene expression against pesticide toxicity. Hence, results of the present study intervenes into a new approach of justifying the deleterious side effects of pesticides that are commonly used, and how green leafy vegetables can help ameliorate those harmful effects

Protective role of Ipomoea aquatica Forsk. crude extract on rat tissues in the presence of acephate and carbofuran by histopathology and cytometric determination

Ipomoea aquatica Forsk., commonly called water spinach ( ‘kalmi’ in Bengali) is an underexploited local green leafy vegetable having enormous scope as a cheap antioxidant source. The study explores the ameliorative effect of aqueous I. aquatica extract (IAE) in acephate and carbofuran treated Wistar male rats. Aqueous IAE (@ 20 mg/kg body wt.), administered to rats treated with organophosphate acephate (@ 30 mg/kg body wt.) and carbamate carbofuran (@ 0.1 mg /kg body wt.), attenuated the cholinesterase activity in brain, liver and cellular blood and reformed the histological perturbations in the brain cortex as well as the kidney anomalies, to a good extent. The IAE also upregulated the NF-E2-related factor-2 (Nrf-2) and MnSOD gene expression against pesticide toxicity. Hence, results of the present study intervenes into a new approach of justifying the deleterious side effects of pesticides that are commonly used, and how green leafy vegetables can help ameliorate those harmful effects

Structural change in a B-DNA helix with hydrostatic pressure

Study of the effects of pressure on macromolecular structure improves our understanding of the forces governing structure, provides details on the relevance of cavities and packing in structure, increases our understanding of hydration and provides a basis to understand the biology of high-pressure organisms. A study of DNA, in particular, helps us to understand how pressure can affect gene activity. Here we present the first high-resolution experimental study of B-DNA structure at high pressure, using NMR data acquired at pressures up to 200 MPa (2 kbar). The structure of DNA compresses very little, but is distorted so as to widen the minor groove, and to compress hydrogen bonds, with AT pairs compressing more than GC pairs. The minor groove changes are suggested to lead to a compression of the hydration water in the minor groove

Amelioration of galactosamine-induced nephrotoxicity by a protein isolated from the leaves of the herb, Cajanus indicus L

<p>Abstract</p> <p>Background</p> <p>Galactosamine (GalN), an established experimental toxin, mainly causes liver injury via the generation of free radicals and depletion of UTP nucleotides. Renal failure is often associated with end stage liver damage. GalN intoxication also induces renal dysfunction in connection with hepatic disorders. Present study was designed to find out the effect of a protein isolated from the leaves of the herb <it>Cajanus indicus </it>against GalN induced renal damage.</p> <p>Methods</p> <p>Both preventive as well as curative effect of the protein was investigated in the study. GalN was administered intraperitoneally at a dose of 800 mg/kg body weight for 3 days pre and post to protein treatment at an intraperitoneal dose of 2 mg/kg body weight for 4 days. The activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione-S-transferase (GST), levels of cellular metabolites, reduced glutathione (GSH), total thiols, oxidized glutathione (GSSG) and lipid peroxidation end products were determined to estimate the status of the antioxidative defense system. In addition, serum creatinine and urea nitrogen (UN) levels were also measured as a marker of nephrotoxicity.</p> <p>Results</p> <p>Results showed that GalN treatment significantly increased the serum creatinine and UN levels compared to the normal group of mice. The extent of lipid peroxidation and the level of GSSG were also enhanced by the GalN intoxication whereas the activities of antioxidant enzymes SOD, CAT, GR and GST as well as the levels of total thiols and GSH were decreased in the kidney tissue homogenates. Protein treatment both prior and post to the toxin administration successfully altered the effects in the experimental mice.</p> <p>Conclusion</p> <p>Our study revealed that GalN caused a severe oxidative insult in the kidney. Protein treatment both pre and post to the GalN intoxication could protect the kidney tissue against GalN induced oxidative stress. As GalN induced severe hepatotoxicity followed by renal failure, the protective role of the protein against GalN induced renal damages is likely to be an indirect effect. Since the protein possess hepatoprotective activity, it may first ameliorate GalN-induced liver damage and consequently the renal disorders are reduced. To the best of our knowledge, this is probably the first report describing GalN-induced oxidative stress in renal damages and the protective role of a plant protein molecule against it.</p

Molecular association of glucose-6- phosphate isomerase and pyruvate kinase M2 with glyceraldehyde-3-phosphate dehydrogenase in cancer cells

Background: For a long time cancer cells are known for increased uptake of glucose and its metabolization through glycolysis. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key regulatory enzyme of this pathway and can produce ATP through oxidative level of phosphorylation. Previously, we reported that GAPDH purified from a variety of malignant tissues, but not from normal tissues, was strongly inactivated by a normal metabolite, methylglyoxal (MG).Molecular mechanism behind MG mediated GAPDH inhibition in cancer cells is not well understood. Methods: GAPDH was purified from Ehrlich ascites carcinoma (EAC) cells based on its enzymatic activity. GAPDH associated proteins in EAC cells and 3-methylcholanthrene (3MC) induced mouse tumor tissue were detected by mass spectrometry analysis and immunoprecipitation (IP) experiment, respectively. Interacting domains of GAPDH and its associated proteins were assessed by in silico molecular docking analysis. Mechanism of MG mediated GAPDH inactivation in cancer cells was evaluated by measuring enzyme activity, Circular dichroism (CD) spectroscopy, IP and mass spectrometry analyses. Result: Here, we report that GAPDH is associated with glucose-6-phosphate isomerase (GPI) and pyruvate kinase M2 (PKM2) in Ehrlich ascites carcinoma (EAC) cells and also in 3-methylcholanthrene (3MC) induced mouse tumor tissue. Molecular docking analyses suggest C-terminal domain preference for the interaction between GAPDH and GPI. However, both C and N termini of PKM2 might be interacting with the C terminal domain of GAPDH. Expression of both PKM2 and GPI is increased in 3MC induced tumor compared with the normal tissue. In presence of 1 mM MG,association of GAPDH with PKM2 or GPI is not perturbed, but the enzymatic activity of GAPDH is reduced to 26.8 ± 5 % in 3MC induced tumor and 57.8 ± 2.3 % in EAC cells. Treatment of MG to purified GAPDH complex leads to glycation at R399 residue of PKM2 only, and changes the secondary structure of the protein complex. Conclusion: PKM2 may regulate the enzymatic activity of GAPDH. Increased enzymatic activity of GAPDH in tumor cells may be attributed to its association with PKM2 and GPI. Association of GAPDH with PKM2 and GPI could be a signature for cancer cells. Glycation at R399 of PKM2 and changes in the secondary structure of GAPDH complex could be one of the mechanisms by which GAPDH activity is inhibited in tumor cells by MG

Aqueous extract of Terminalia arjuna prevents carbon tetrachloride induced hepatic and renal disorders

BACKGROUND: Carbon tetrachloride (CCl(4)) is a well-known hepatotoxin and exposure to this chemical is known to induce oxidative stress and causes liver injury by the formation of free radicals. Acute and chronic renal damage are also very common pathophysiologic disturbances caused by CCl(4). The present study has been conducted to evaluate the protective role of the aqueous extract of the bark of Termnalia arjuna (TA), an important Indian medicinal plant widely used in the preparation of ayurvedic formulations, on CCl(4 )induced oxidative stress and resultant dysfunction in the livers and kidneys of mice. METHODS: Animals were pretreated with the aqueous extract of TA (50 mg/kg body weight) for one week and then challenged with CCl(4 )(1 ml/kg body weight) in liquid paraffin (1:1, v/v) for 2 days. Serum marker enzymes, namely, glutamate pyruvate transaminase (GPT) and alkaline phosphatase (ALP) were estimated in the sera of all study groups. Antioxidant status in both the liver and kidney tissues were estimated by determining the activities of the antioxidative enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST); as well as by determining the levels of thiobarbutaric acid reactive substances (TBARS) and reduced glutathione (GSH). In addition, free radical scavenging activity of the extract was determined from its DPPH radical quenching ability. RESULTS: Results showed that CCl(4 )caused a marked rise in serum levels of GPT and ALP. TBARS level was also increased significantly whereas GSH, SOD, CAT and GST levels were decreased in the liver and kidney tissue homogenates of CCl(4 )treated mice. Aqueous extract of TA successfully prevented the alterations of these effects in the experimental animals. Data also showed that the extract possessed strong free radical scavenging activity comparable to that of vitamin C. CONCLUSION: Our study demonstrated that the aqueous extract of the bark of TA could protect the liver and kidney tissues against CCl(4)-induced oxidative stress probably by increasing antioxidative defense activities

Studies on the crystal growth of rice bran wax in a hexane medium

Rice bran oil (RBO) is well known for its high wax content (2-4 %). A good separation of waxes must be ensured through the formation of crystals that can be removed with a minimal retention of oil to maintain high yields of refined oil. In the present study, the form and size distribution of RBO wax crystals were investigated using a laser diffraction technique. An attempt was made to study the effect of cooling on growth and size distribution of RBO wax crystals in hexane medium, and it showed that high cooling rate and low temperature induces the formation of a great number of small nuclei. In addition, experiments were performed to evaluate the effect on the growth of wax crystals of successive additions of gum and pure TG to the medium. The entire experiment was designed to optimize the temperature and incubation time of wax crystallization to facilitate the efficient separation of wax from crude RBO-hexane miscella using membrane technology