Showing papers by "University of Madras published in 1996"
TL;DR: The results suggest that the antioxidant deficiency and excessive peroxide-mediated damage may appear early on in non-insulin-dependent diabetes mellitus, before the development of secondary complications.
Abstract: 1. This study was conducted on 467 cases of non-insulin-dependent diabetes mellitus and 180 healthy controls. Lipid peroxidation products in plasma and erythrocytes were assayed as thiobarbituric acid reactive substances, along with the erythrocyte antioxidant enzymes, namely superoxide dismutase, catalase and glutathione peroxidase. In addition, scavenger vitamins A, C and E and reduced glutathione levels in blood were also measured. 2. Lipid peroxidation was significantly raised within the first 2 years of diagnosis, and superoxide dismutase, catalase, reduced glutathione and vitamins C and E were significantly lowered. 3. These changes were correlated with the duration of the disease and were of a higher magnitude with the development of complications. 4. The results suggest that the antioxidant deficiency and excessive peroxide-mediated damage may appear early on in non-insulin-dependent diabetes mellitus, before the development of secondary complications.
307 citations
TL;DR: Powder X-ray diffraction analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis were employed to characterize the coral and to optimize the processing parameters as well as to confirm the hydroxyapatite formation.
205 citations
TL;DR: It is concluded that antioxidant status is poor in both IGT and NIDDM, suggesting an overlap of frank diabetic state in those classified as IGT, and it is possible that antioxidant therapy might retard progression from IGT to NID DM.
Abstract: A total of 105 subjects with impaired glucose tolerance were classified into two groups, 51 subjects with plasma glucose > 11.1 mmol l-1 in one of the blood samplings during OGTT, but at 2 h being less than < 11.1 mmol l-1 were classified as early hyperglycaemics. Fifty-four cases were classified as true IGT, with fasting plasma glucose < 7.8 mmol l-1 and post plasma glucose level between 7.8 and 11.1 mmol l-1. Age and sex matched groups of normals (healthy adults) and NIDDM cases without symptomatic secondary complications were also included in the study. Lipid peroxidation (LPO) product in plasma, erythrocyte, and erythrocyte cell membrane were found to be significantly elevated (p < 0.001) in IGT, early hyperglycaemia and diabetes mellitus while glycosylated haemoglobin was also higher. Antioxidant enzymes superoxide dismutase and catalase were significantly lower in red blood cells obtained from IGT and early hyperglycaemic groups. They were closer to the levels showed in NIDDM confirming that antioxidant deficiency is already present in subjects classified as impaired glucose tolerant. Among the antioxidant scavengers, reduced glutathione (GSH) and ascorbic acid are reduced by 15% and 20% in IGT and NIDDM, respectively. We conclude that antioxidant status is poor in both IGT and NIDDM, suggesting an overlap of frank diabetic state in those classified as IGT. It is possible that antioxidant therapy might retard progression from IGT to NIDDM.
168 citations
TL;DR: In this article, the synthesis, characterization, and electrochemical behavior of some acridinedione derivatives are reported, and a mechanistic scheme for the electrochemical oxidation is proposed.
Abstract: The synthesis, characterization, and electrochemical behavior of some acridinedione derivatives are reported. Cyclic voltammetric studies show that all the dyes undergo irreversible oxidation irrespective of the substitution on the nitrogen. The product formed on oxidation is the aromatic derivative in the case of N-H compounds and the acridinium salt in the case of the N-substituted compounds, which have been isolated and characterized. Formation of an intermediate carbon-centered radical is observed as evidenced by ESR spin-trapping experiments. A mechanistic scheme for the electrochemical oxidation is proposed. On carrying out reduction after oxidation, different products are formed depending on the substitution on the nitrogen. There is no reduction of the oxidized product in the case of N-H compounds, and compounds with substitution on nitrogen undergo reduction consistent with the observation in N-alkylpyridinium salts.
141 citations
TL;DR: The hypocholesterolemic action of TCR appears to be due to an upregulation of hepatic LDL-receptors resulting in greater influx of plasma cholesterol into the liver.
96 citations
TL;DR: In this article, a new class of laser dyes called bisacridinediones (3a-e) were described, based on the synthesis of 9-alkyl, 10-hexahydro, 9,10-dialkyl and 10-aryl.
Abstract: Synthesis of 9-alkyl, 10-alkyl, 9,10-dialkyl, and 10-aryl-3,4,6,7,9,10-hexahydro-1,8(2H,5H)acridinedione (2a–r) are described as a new class of laser dyes. Reactions of diamines with methylene bis(cyclohexane-1,3-dione) yielded the respective bisacridinediones (3a–e). These dyes lase around 478–494 nm and are compared with the standard dye coumarin-102. © 1996 John Wiley & Sons, Inc.
76 citations
TL;DR: It is suggested that eugenol, by incorporating into the membrane protects it from free radical attack, and by maintaining the activities of the antioxidant enzymes at normal levels removes the oxidative stress imposed by CCl 4.
Abstract: Simultaneous administration of eugenol (10.7 mg/kg of body weight/day) with carbon tetrachloride (CCl 4 ) (1.195 g/kg of body weight, i.p. 3 times a week for 2 weeks) to rats protected the loss of functional integrity and membrane lipid alterations in red blood cells (RBCs) induced by oxidative stress. Eugenol, an allyl benzene that is the major ingredient of cloves, Osimum, and nutmeg, inhibits the accumulation of lipid peroxidation products in red blood cells and maintains the activities of the antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase(s), glutathione reductase, and glucose-6-phosphate dehydrogenase at normal levels. The CCl 4 -induced increase in membrane fluidity was decreased by eugenol, and the altered activities of membrane-bound enzymes Na + , K + -ATPase, NADH-dehydrogenase, and Ca 2+ -ATPase were normalized. Eugenol exhibited a concentration-dependent binding into RBC membranes in vitro, and it also inhibited the hemolysis of RBCs induced by liver S9 fraction-treated CCl 4 . Hence, it is suggested that eugenol, by incorporating into the membrane protects it from free radical attack, and by maintaining the activities of the antioxidant enzymes at normal levels removes the oxidative stress imposed by CCl 4 .
64 citations
TL;DR: In this paper, a diver-assisted inspection of the tunnel proved that the green mussel Perna viridis (L.) was the major component of the fouling community inside the cooling conduits.
63 citations
TL;DR: The data obtained clearly indicate that the Semecarpus anacardium is effective at the dose level of 150 mg/kg body weight in adjuvant-induced arthritis in albino Wistar rats.
Abstract: 1. Adjuvant-induced arthritis in rats is used as a pathologic model for chronic inflammatory disease to evaluate the efficacy of therapeutic agents. 2. In the present work, attempts have been made to study the potency of a milk extract of Semecarpus anacardium (Serankottai Nei), a Siddha preparation from Semecarpus anacardium nut, which has been shown to have antiarthritic effects. 3. Experimental arthritis induces a significant modification in lysosomal enzyme release and total carbohydrate components of glycoprotein. 4. Milk extract was administered at the dose level of 50, 100, 150, 200, and 250 mg/kg body weight in olive oil orally (volume 0.5 ml) after 14 days from the day of adjuvant injection. 5. After administration of the extract the lysosomal enzyme activity and protein-bound carbohydrate component levels were significantly normalized. 6. The data obtained clearly indicate that the Semecarpus anacardium is effective at the dose level of 150 mg/kg body weight in adjuvant-induced arthritis in albino Wistar rats.
56 citations
TL;DR: In this article, the oscillatory behavior of solutions of second order nonlinear neutral delay difference equations is investigated and several examples which dwell upon the importance of their results are also illustrated.
51 citations
TL;DR: Different tissues exhibited oxalate binding showing ubiquitous nature, and calf thymus H1 showed maximal binding similar to liver histones, and di- and tri-carboxylate carrier inhibitors and thiol modifying agents significantly lowered the binding activity.
Abstract: The rat liver nuclear oxalate binding protein was isolated, purified by anion and cation exchange column chromatography using Diethyl Amino Ethyl Sephadex, Carboxy Methyl Cellulose and Carboxy Methyl Sephadex C-50 ion exchangers. The purified oxalate binding protein was found to be H1B of H1 fraction of histories. Kinetic analysis of oxalate binding showed the presence of two affinity sites, one with Kd of 133.5 nM and Bmax of 40 pmoles and another with Kd of 262.5 nM and Bmax of 210 pmoles. The optimal oxalate binding was at pH 4.2 and at 28°C. The oxalate binding was specific and reversible and not due to ionic charge interaction. The IC50 of other dicarboxylates was higher than that of oxalate. EGTA had no effect on oxalate binding but di- and tri-carboxylate carrier inhibitors and thiol modifying agents significantly lowered the binding activity. Oxalate binding to histones was significantly reduced in the presence of DNA or nucleotides, but RNA had no effect. ATP completely inhibited the oxalate binding activity at 1 mM concentration. Different tissues exhibited oxalate binding showing ubiquitous nature. Calf thymus H1 showed maximal binding similar to liver histones.
TL;DR: The results indicate the possibility of using selective organic amendments to enhance development of native AM fungi and thus reduce disease incidence in rice plants.
Abstract: The effect of various organic soil amendments on arbuscular myorrhizal (AM) fungal activity on rice plants was tested under greenhouse and field conditions with reference to sheath blight (ShB) disease caused by Rhizoctonia solani. AM spore density, per cent infection, and intensity of infection were increased by organic amendments, whilst ShB disease was decreased. Certain amendments, especially green leaf manure, stimulated arbuscule development in rice plants. Mycorrhiza formation and sporulation were higher with healthy rice plants than with rice plants infected with R. solani. Our results indicate the possibility of using selective organic amendments to enhance development of native AM fungi and thus reduce disease incidence.
Journal Article•
TL;DR: This experiment proved the anti hepatitis B virus property of P. amarus at cellular level and further confirmed its beneficial use in the treatment of acute and chronic hepatitis B and healthy carriers of HBV.
Abstract: Alexander cell line, an human hepatocellular carcinoma derived cell line which has the property of secreting HBsAg in the supernatant was used to study the antiviral property of phyllanthus amarus. Aquous extract of Phyllanthus amarus was evaluated for its in vitro ability to inhibit HBsAg secretion on a dose dependent manner. It was seen that P. amarus at 1mg/ml concentration on a single dose inhibited the secretion of HBsAg for a period of 48 hours. This experiment proved the anti hepatitis B virus property of P. amarus at cellular level and further confirmed its beneficial use in the treatment of acute and chronic hepatitis B and healthy carriers of HBV.
TL;DR: Gas phase N-methylation of aniline with methanol was carried out in a fixed bed flow reactor over the calcined Mg II Al III layered double hydroxides (LDHs) with various atomic ratios of Mg:Al from 3 to 10 as discussed by the authors.
Abstract: Gas phase N-methylation of aniline with methanol was carried out in a fixed bed flow reactor over the calcined Mg II Al III layered double hydroxides (LDH) with various atomic ratios of Mg:Al from 3 to 10. Only a single product (N-methylaniline) was formed. The catalytic activity, selectivity, longevity, time on stream and reactivations are investigated based on the extent of mono-alkylated product formations. All calcined LDHs were more active than the physical mixtures of MgO Al 2 O 3 . A higher surface area and lattice parameter of 4:1 mole ratio of calcined LDHs effectively produced a maximum conversion of 68% at 425°C at a feed mixture mole ratio of 1:7 (aniline to methanol) when the flow rate was 5 ml/h over all other catalysis.
TL;DR: DL alpha-lipoic acid is a dithiol which is effective in rendering protection against cadmium-associated liver damage, by virtue of its two sulfhydryl moieties, and this work highlights the antioxidant property of lipoic Acid and its efficacy in mitigating cad mium- associated liver assault even in the absence of glutathione synthesis.
Abstract: Cadmium, a divalent metal toxicant, preferentially localizes in hepatocytes and causes liver injury. DL alpha-lipoic acid is a dithiol which is effective in rendering protection against cadmium-associated liver damage, by virtue of its two sulfhydryl moieties. Lipoate was administered to cadmium-exposed rats which were either prior administered with buthionine sulfoximine to deplete liver glutathione or not. During lipoate treatment, significant protection was rendered against cadmium toxicity even under glutathione-depleted experimental condition. This highlights the antioxidant property of lipoic acid and its efficacy in mitigating cadmium-associated liver assault even in the absence of glutathione synthesis.
TL;DR: Field trials with an Ant-deficient mutant carrying a single-site mini-Tn 5 -Km insertion revealed that antibiotic production by Pf714 was required for the control of blast as well as sheath blight, and data show that Pf7-14 was as effective as the fungicide tricyclazole in controlling these rice diseases.
TL;DR: In this paper, the principal component analysis (PCA) of 23 features of the geological, geomorphological, basin morphometry and land-use aspects of the Tamiraparani basin defined in terms of 63 micro-basins was performed.
TL;DR: It is evident that quercetin has an inhibitory effect on DMBA-induced carcinogenesis and further studies will throw more light on its use as a chemopreventive agent against oral cancer.
Abstract: The inhibitory effect of dietary supplementation with flavonol quercetin on 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis was investigated. Dietary quercetin inhibited the incidence of both papillomas and tumors induced by DMBA. The fluorescence spectra of papillomas and tumors showed different prominent maxima and a characteristic peak around 620-630 nm, which could be attributed to the accumulation of porphyrin compounds. Further, the fluorescence intensities at 630 nm (FI630nm) were elevated, whereas the ratio FI530nm/FI630nm was decreased in DMBA-induced lesions. Quercetin treatment significantly decreased FI630nm and increased the ratio FI520nm/FI630nm when compared with DMBA-induced lesions. It is therefore evident that quercetin has an inhibitory effect on DMBA-induced carcinogenesis and further studies will throw more light on its use as a chemopreventive agent against oral cancer.
TL;DR: In this article, a study was designed to determine whether dietary supplementation of DL α-lipoic acid (15 and 30 mg/kg), a "meta-vitamin," to cadmium-intoxicated rats (3 mg/ kg) affords protection against the oxidative stress caused by the metal, and the liver and kidney of the metal-administered rats showed elevated levels of hydroxyl radicals and malondialdehyde (basal and induced), a decreased level of antioxidants-reduced glutathione, total thiols, protein thiol
Abstract: Cadmium as an environmental pollutant has aroused great concern due to its toxic effects on various body tissues. Supplementation of thiol compounds has been suggested to protect against the toxic effects of reduced oxygen species by contributing to the thiol pool of the cell. The present study was designed to determine whether dietary supplementation of DL α-lipoic acid (15 and 30 mg/kg), a “meta-vitamin,” to cadmium-intoxicated rats (3 mg/kg) affords protection against the oxidative stress caused by the metal. The liver and kidney of the metal-administered rats showed elevated levels of hydroxyl radicals and malondialdehyde (basal and induced), a decreased level of antioxidants-reduced glutathione, total thiols, protein thiols, nonprotein thiols, ascorbate, α-tocopherol and retinol and antioxidizing enzymes-superoxide dismutase, catalase, τ-glutamyl transpeptidase, glutathione peroxidase, glucose-6-phosphate dehydrogenase, glutathione reductase, and glutathione-S-transferase. Lipoate supplementation changed the tissue redox state directly by scavenging the free radicals and indirectly by bolstering the antioxidants and antioxidizing enzyme defenses. In vitro studies revealed that, among the mono and dithiols (glutathione, cysteine, dithiothreitol, and lipoic acid), lipoic acid was the most potent scavenger of free radicals produced during cadmium-induced hepatotoxicity. The drug contributes its thiol groups to detoxify the divalent metal and subsequently ameliorates the cell membrane integrity.
TL;DR: Asymmetric syntheses of the diketones S-1, S-6, and S-10 from the precursors 3, 5 and 8 respectively have been carried out in the absence of solvent employing S-proline as chiral auxiliary as mentioned in this paper.
Abstract: Asymmetric syntheses of the diketones S-1, S-6, and S-10 from the precursors 3, 5 and 8 respectively have been carried out in the absence of solvent employing S-proline as chiral auxiliary.
01 Jan 1996
TL;DR: The vesicular arbuscular mycorrhizae (VAM) help in conversion of arid soil to fertile and productive soil, and by synergistic action with nitrogen fixing nodulating organisms enhance mineral nutrition and growth of crop plants.
Abstract: The vesicular arbuscular mycorrhizae (VAM) help in conversion of arid soil to fertile and productive soil. VAM fungi increase plant growth through enhanced nutrient uptake and cycling of phosphorus, nitrogen, carbon, zinc, copper and other minerals. The bacteria associated with mycorrhizal fungi solubilize P which is transported through the mycorrhizal fungi to plant. Mycorrhizal fungal hyphae produce phosphatases and organic acids that enhance the availability of soil P by weathering P from the clay matrix and maintaining the solution P by binding Ca with the secreted oxalates. There are reports that N fixed by one plant has been transported to an adjacent, non-fixing plant through mycorrhizal fungal hyphae. Mycorrhizal hyphae form aggregates by directly binding soil particles possibly by producing polysaccharides. These aggregates are a major input into systems with low organic matter. Apart from nutrient uptake, mycorrhizae also enhance the transport of water from soil to plant. VAM fungal inoculated plants exhibit increased drought resistance and resistance to fungal root diseases and nematode diseases. VAM fungi initiate host defence response in roots by increasing phenols, peroxidases, phytoalexins etc. VAM fungi by synergistic action with nitrogen fixing nodulating organisms enhance mineral nutrition and growth of crop plants. Agricultural practices such as fallowing, tillage, top soil removal, fires, water logging and the use of chemicals like pesticides and fertilizers can influence VAM inoculum potential. Large differences exist between plant species in their dependence of VAM fungi for uptake and growth. The selection of VAM fungi, inoculum production and inoculation techniques are important factors which play a major role in favouring good results of VAM fungi for agricultural systems. The benefits of VAM fungi for sustainable agriculture are immense.
TL;DR: The quantum theory of continuous measurements is an appropriate generalization of the conventional quantum theory, which is adequate to deal with counting experiments where a detector monitors a system continuously over an interval of time and records the times of occurrence of a given type of event, such as the emission or arrival of a particle.
Abstract: We present an overview of the quantum theory of continuous measurements and discuss some of its important applications in quantum optics. Quantum theory of continuous measurements is the appropriate generalization of the conventional formulation of quantum theory, which is adequate to deal with counting experiments where a detector monitors a system continuously over an interval of time and records the times of occurrence of a given type of event, such as the emission or arrival of a particle.
TL;DR: It is shown that nauplius stage larvae of penaeid prawns can be considered a suitable stage for cryopreservation, both by the conventional slow cooling method and also the vitrification technique as it allows use of high levels of cryoprotectant.
TL;DR: In the crystal structure of a di-aIkyne that contains a cocrystallized water molecule, an unprecedentedly rich system of interconnected O(H)⋯O, CH ⋯ and O(π) hydrogen bonds is found as discussed by the authors.
TL;DR: In this paper, the emission, absorption and fluorescence excitation spectra of thionine dye covelently linked to poly(acrylamidoglycolic acid) were studied.
Abstract: Thionine dye was condensed with poly(acrylamidoglycolic acid) (P(AGA)) and poly (methylolacrylamide) (P(MAAM)). Phenosafranine dye was condensed with P(MAAM). The emission, absorption and fluorescence excitation spectra of thionine dye covelently linked to P(AGA) were studied. Electrochemical reduction of P (AGA)-bound thionine shows that both monomeric thionine and non-reducible thionine are bound to the macromolecule; bound non-reducible thionine is non-fluorescent in nature. The polymer-bound thionine and phenosafranine dyes in aqueous solution exhibit biexponential fluorescence decay, in contrast with the corresponding unbound dye, which is attributed to the effect of the macromolecular chain conformation and solvent environment on the photophysics of the polymer-bound dyes. The excited state which decays with a shorter lifetime is suggested to be in a more polar aqueous environment (as in the case of the unbound dyes dissolved in aqueous medium), whereas the excited state which shows a longer lifetime is situated in a hydrophobic environment inside the coil of the polymeric chain where less interaction with the solvent molecules is experienced.
TL;DR: In this article, a method for the synthesis of 4-substituted β-carbolines from the corresponding N-allylisogramine derivative is reported using intramolecular free radical cyclisation or Heck reaction.
TL;DR: In this article, a new class of imaginary roots called purely imaginary roots is introduced, and a necessary and sufficient condition for an imaginary root to be purely imaginary is given, which is the same as the condition for a purely imaginary root in Kac-Moody algebras.
Abstract: In this paper, we introduce a new class of imaginary roots, called purely imaginary roots and give a necessary and sufficient condition for an imaginary root to be purely imaginary,thereby giving a complete classification of those Kac-Moody algebras with the purely imaginary property, namely, all their imaginary roots are purely imaginary. We also define a new class of non-hyperbolic indefinite Kac-Moody algebras, called the extended hyperbolic kac-Moody algebras possessing the purely imaginary property.
TL;DR: The effect of ascorbic acid supplementation was determined in young and aged rats for 15, 30, and 60 days, where cholesterol, triglycerides, phospholipids, and lipid peroxidation were considerably high, whereas, antioxidants superoxide dismutase, catalase, glutathione peroxidase,glutathione, ascorBic acid, and α-tocopherol were low.
Abstract: Molecular mechanisms responsible for age-dependent deterioration of biochemical functions remain unclear. We determined the effect of ascorbic acid supplementation (20 mg/100 g body weight/day) in young and aged rats for 15, 30, and 60 days. In the aged animals cholesterol, triglycerides, phospholipids, and lipid peroxidation were considerably high, whereas, antioxidants superoxide dismutase, catalase, glutathione peroxidase, glutathione, ascorbic acid, and α-tocopherol were low. Administration of ascorbic acid reverted these age-associated differences to the status comparable to young rats.
Journal Article•
TL;DR: A-Tocopherol pretreated rats showed a nearnormal ECG pattern, levels of lipid peroxides, activities of marker enzymes and a near normal histology of heart and aorta on isoproterenol administration.
Abstract: The effect of a-tocopherol (6 mg/lOO g body wt, orally, daily for 90 days) pretreatment in isoproterenol (20 mg/IOO g body wt, subcutaneously, twice at an interval of two days at the end of the a-tocopherol pretreatment) induced myocardial infarction was studied in rats. Isoproterenol administered rats showed electrocardiographic changes suggestive of myocardial infarction with marked ST segment elevation, Q waves appearance and a significant increase in heart rate. In isoproterenol administered rats, a significant decrease was observed in the activities of marker enzymes such as aspartate amino transferase, alanine amino transferase, lactate dehydrogenase and creatine kinase in heart and aorta with a significant increase in their activities in serum. The levels of lipid peroxides in terms of "TBA reactants" increased significantly in serum, heart and aorta on isoproterenol administration. The histology of heart and aorta showed marked fragmentation of muscle fibres and necrotic lesions in isoproterenol administered rats. a-Tocopherol pretreated rats showed a near normal ECG pattern, levels of lipid peroxides, activities of marker enzymes and a near normal histology of heart and aorta on isoproterenol administration.
TL;DR: In this paper, an electron transfer reaction pathway is proposed for phenylalanine and histidine, whereas a hydrogen abstraction pathway is invoked for the other amino acids, based on the magnitudes of the second-order rate constants and the observation of cation radicals.
Abstract: The reactions of nitrate radical (photochemically generated by the flash photolysis of a mixture of ceric ammonium nitrate and nitric acid) with amino acids are reported. An electron transfer reaction pathway is proposed for phenylalanine and histidine, whereas a hydrogen abstraction pathway is invoked for the other amino acids, based on the magnitudes of the second- order rate constants and teh observation of cation radicals. The reactivity of the nitrate radical is compared with that of other oxidizing radicals, such as Cl 2 − CO 3 − and SO 4 − . The nitrte radical is expected to show a higher reactivity than SO 4 − based on their redox couples, but an inverse reactivity relationship is observed and is suggested to be due to the difference in solvation in the transition state.