Showing papers by "University of Madras published in 1999"
TL;DR: In this paper, the electrocatalytic properties of hexacyanoferrates were studied by cyclic voltammetry using hydrazine as substrate and it was observed that the current ratio is higher at slow scan rates and lower at high scan rates.
Abstract: The electrocatalytic properties of electrodes modified with metal [Cr(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Cd(II) and In(III)] hexacyanoferrates(II) were studied by cyclic voltammetry using hydrazine as substrate. The electrodes were prepared by mechanically transferring microparticles of the hexacyanoferrates onto the surface of a paraffin impregnated graphite electrode. The catalytic activities of these compounds were compared based on the ratio of the total current for the catalytic oxidation to the current for the modified electrode. This ratio has been calculated at the peak potentials of the cyclic voltammograms and also at some fixed anodic potentials. As expected for an electrocatalytic reaction, it was observed that the current ratio is higher at slow scan rates and lower at high scan rates. The catalytic activities of hexacyanoferrates are rather complex and they do not follow any uniform pattern. The hexacyanoferrates of manganese, zinc and indium turned out to possess the highest catalytic activity.
135 citations
TL;DR: The degree of radiation affects the extent of the depression of the antioxidant enzyme activities and increases lipid peroxidation, thereby rendering the system inefficient in management of the free radical attack.
93 citations
TL;DR: In this paper, the reactions of diperiodatoargentate(III) with glycine and related compounds have been examined and it was shown that the reaction has a second order rate constant of (0.2-1.6)×10 4 dm 3 mol −1 s −1 whereas the redox process occurs at a rate of ( 0.3-6.0)× 10 2 dm3 mol − 1 s − 1 except in case of cysteine with which these processes occurred by an order of magnitude faster.
90 citations
TL;DR: In this paper, an ac ionic conductivity study of 3 mol% yttria stabilized zirconia (3YSZ) in tetragonal phase shows maximum conductivity both in grains and grain boundaries for a range of temperatures.
86 citations
TL;DR: Observations suggest that the orally administered extract of O. sanctum may have the ability to prevent the early events of carcinogenesis.
86 citations
TL;DR: Serum levels of interleukin-6 were decreased during late puberty and were negatively correlated with bone density in TS III and IV girls, which are consistent with a model in which the sex steroid hormone-induced increase in the IGF system leads to an increase in longitudinal growth and periosteal bone expansion.
Abstract: In this study we evaluated the role of cytokines and insulin-like growth factor (IGF) system in mediating the skeletal changes that occur during puberty by determining the relationship between serum levels of cytokines and IGF system components vs. 1) bone formation and resorption parameters in serum and urine, 2) bone density, and 3) metacarpal bone indexes in 65 pubertal girls. Lumbar bone mineral density and metacarpal width increased significantly both between Tanner stages (TS) II and III and between TS III and IV, whereas metacarpal length and serum levels of stimulatory IGF system components increased significantly only between TS II and III. Biochemical markers of bone turnover were significantly less in TS IV girls than in TS II and III girls. In general, serum levels of IGF system components showed a significant positive correlation to bone density in TS II and III girls, whereas bone resorption markers corrected for creatinine showed a significant negative correlation to bone density in TS III and IV girls. Serum levels of IGF system components showed a significant positive correlation to serum osteocalcin levels as well as metacarpal width in TS II girls, whereas urinary levels of bone resorption markers showed a significant negative correlation to metacarpal width in TS IV girls. Serum levels of interleukin-6 were decreased during late puberty and were negatively correlated with bone density in TS III and IV girls. Our data are consistent with a model in which the sex steroid hormone-induced increase in the IGF system leads to an increase in longitudinal growth and periosteal bone expansion, whereas the sex steroid hormone-induced reduction in bone turnover (possibly via cytokines) leads to an increase in cortical thickness via endosteal regulation.
86 citations
Journal Article•
TL;DR: In this paper, a study on the Kallankurichchi Formation in order to understand the elemental behaviour in marine limestones of the Tiruchirapalli Cretaceous was carried out.
Abstract: Studies on calcium carbonate (CaCO 3 ), trace elements and rare earth elements were carried out on the Kallankurichchi Formation in order to understand the elemental behaviour in marine limestones of the Tiruchirapalli Cretaceous. Variation in EREE content between Sandy Fossiliferous Limestone (SFL) and Fossiliferous Limestone (FL) can be explained as due to the varying amounts of terrigenous material present in the limestones. PAAS (Post Archaean Australian Shale) normalised REE patterns and La N /Yb N ((La Sample /La Shale )/(Yb Sample /Yb Shale )) ratios suggest that the terrestrial rocks are the major source for REE in these limestones. The SFL and FL show negative Ce anomalies, with slight variation between these limestones. The negative correlation between CaCO 3 and Ce/Ce* values indicates that the observed Ce anomalies are not related to the CaCO 3 content in SFL and FL, whereas Ce/Ce* values show positive correlation with detrital elements implying that the observed variations in the Ce anomalies resulted from the variation in the terrigenous material supplied by the continental area. SFL and FL show low U/Th ratio and U content. Low U contents suggest that the oxic condition prevailed in the bottom water and sediment column during the deposition of Kallankurichchi Formation.
69 citations
TL;DR: The results of this study demonstrate the existence of six diagnostically relevant antigenic domains within the HEV ORF2 protein.
Abstract: The antigenic composition of the hepatitis E virus (HEV) protein encoded by open reading frame 2 (ORF2) was determined by using synthetic peptides. Three sets of overlapping 18-, 25-, and 30-mer peptides, with each set spanning the entire ORF2 protein of the HEV Burma strain, were synthesized. All synthetic peptides were tested by enzyme immunoassay against a panel of 32 anti-HEV-positive serum specimens obtained from acutely HEV-infected persons. Six antigenic domains within the ORF2 protein were identified. Domains 1 and 6 located at the N and C termini of the ORF2 protein, respectively, contain strong immunoglobulin G (IgG) and IgM antigenic epitopes that can be efficiently modeled with peptides of different sizes. In contrast, antigenic epitopes identified within the two central domains (3 and 4) were modeled more efficiently with 30-mer peptides than with either 18- or 25-mers. Domain 2 located at amino acids (aa) 143 to 222 was modeled best with 25-mer peptides. A few 30-mer synthetic peptides derived from domain 5 identified at aa 490 to 579 demonstrated strong IgM antigenic reactivity. Several 30-mer synthetic peptides derived from domains 1, 4, and 6 immunoreacted with IgG or IgM with more than 70% of anti-HEV-positive serum specimens. Thus, the results of this study demonstrate the existence of six diagnostically relevant antigenic domains within the HEV ORF2 protein.
66 citations
TL;DR: In this article, the main aim of the study was to test the hypothesis that skeletal muscle ATP concentration, creatine phosphokinase and myokinase enzyme activities are stimulated by the sex steroids in both male and female rats.
Abstract: The main aim of the present study was to test the hypothesis that skeletal muscle ATP concentration, creatine phosphokinase and myokinase enzyme activities are stimulated by the sex steroids in both male and female rats (animals were not subjected to any kind of exercise or any training) To test the hypothesis healthy mature (90-120 days old, weighing about 160-180 g) male and female rats were gonadectomized Gonadectomized male and female rats were administered with testosterone (Sigma Chemical, St Louis, MO, USA) at a dose of 100 microg (100 g body weight)-1 day-1 for males and 5 microg (100 g body weight)-1 day-1 for females for 30 days from day 31 post-castration onwards; and oestradiol at a dose of 5 microg (100 g body weight)-1 day-1 for 30 days from day 31 post-castration onwards for both males and females (17beta oestradiol, Sigma Chemical Company, St Louis, MO, USA) The ATP content, creatine phosphokinase and myokinase enzyme activities of skeletal muscles were significantly higher than that of skeletal muscles of female control rats Gonadectomy resulted in a significant decrease in ATP content and creatine phosphokinase myokinase enzyme activities in both male and female rats Testosterone treatment to gonadectomized male rats brought back the parameters to normalcy whereas the same to the female rats enhanced the enzyme activities and ATP contents to the level of control male rats Oestradiol treatment to castrated male rats did not bring about any significant alterations whereas the same in gonadectomized female rats brought them back to normalcy Therefore from the present study it is concluded that testosterone is effective in both males and females whereas oestradiol was effective only in the females in enhancing skeletal muscle energy metabolism
61 citations
TL;DR: Phylogenetic analyses of mtDNA control region sequence from individuals with the 9-bp deletion indicate that it has arisen independently in some Indian tribal populations, implying multiple origins of the 9 -bp deletion in South India.
Abstract: The origins and genetic affinities of the more than 500 tribal populations living in South Asia are widely disputed. This may reflect differential contributions that continental populations have made to tribal groups in South Asia. We assayed for the presence of the intergenic COII/ tRNALys 9-bp deletion in human mtDNA in 646 individuals from 12 caste and 14 tribal populations of South India and compared them to individuals from Africa, Europe, and Asia. The 9-bp deletion is observed in four South Indian tribal populations, the Irula, Yanadi, Siddi, and Maria Gond, and in the Nicobarese. Length polymorphisms of the 9-bp motif are present in the Santal, Khonda Dora, and Jalari, all of whom live in a circumscribed region on the eastern Indian coast. Phylogenetic analyses of mtDNA control region sequence from individuals with the 9-bp deletion indicate that it has arisen independently in some Indian tribal populations. Other 9-bp deletion haplo- types are likely to be of Asian and African origin, implying multiple origins of the 9-bp deletion in South India. These results demonstrate varying genetic affinities of different South Indian tribes to continental populations and underscore the complex histories of the tribal populations living in South Asia. Am J Phys Anthropol 109:147-158, 1999. r 1999 Wiley-Liss, Inc.
58 citations
TL;DR: It can be concluded that the observed anticancer property of Semecarpus anacardium nut extract may also be explained by its strong antioxidant capacity and capability to induce the in vivo antioxidant system.
TL;DR: The results from the experiments involving [U-14C]p-nitrophenol provided the evidence for incorporation of carbon into the cellular constituents and release of CO2 from this insecticide.
Abstract: Organophosphorus insecticides are widely used in agriculture. Despite their biodegradable nature, some are highly toxic and their residues are found in the environment. Reports on the mineralization of a spectrum of these insecticides by a single potential strain are scarce. We have isolated a soil isolate, Pseudomonas sp. A3, through enrichment technique, able to degrade methylparathion (MP), malathion, monocrotophos, and Diazinon. The potential of this strain to mineralize MP as a carbon and/or phosphorus source has been evaluated. On hydrolysis of MP, the aromatic portion (p-nitrophenol) was used as a carbon and energy source whereas the alkyl moiety (dithiomethylphosphorothioate) was broken down for the phosphorus source. The results from the experiments involving [U-14C]p-nitrophenol provided the evidence for incorporation of carbon into the cellular constituents and release of CO2 from this insecticide. During the breakdown of MP, nitrite was released as a catabolic by-product.
TL;DR: In this paper, it was shown that the problem of prime pairs is related to autocorrelation and hence to a Wiener{Khintchine formula, and experimental evidence was given for this.
Abstract: The Wiener{Khintchine formula plays a central role in statistical mechanics. It is shown here that the problem of prime pairs is related to autocorrelation and hence to a Wiener{Khintchine formula. \Experimental" evidence is given for this. c 1999 Elsevier Science B.V. All rights reserved.
TL;DR: Administration of aqueous and ethanolic extracts of Ocimum sanctum to mice bearing Sarcoma-180 solid tumors mediated a significant reduction in tumor volume and an increase in lifespan, which clearly indicate Ocitation sanctum extracts possess anticancer activity.
Abstract: Ocimum sanctum L. (Labiatae), a plant with various medicinal properties, has been investigated against human fibrosarcoma cells (HFS cells) in culture. Treatment with an ethanolic extract of Ocimum sanctum induced cytotoxicity at 50 � g/ml and above. Morphologically the cells showed shrunken cytoplasm and condensed nuclei. The DNA was found to be fragmented on observation in agarose gel electrophoresis. Biochemically the extract-treated HFS cells showed depleted intracellular glutathione and increased levels of lipid peroxidation products. Administration of aqueous and ethanolic extracts of Ocimum sanctum to mice bearing Sarcoma-180 solid tumors mediated a significant reduction in tumor volume and an increase in lifespan. These observations clearly indicate Ocimum sanctum extracts possess anticancer activity.
TL;DR: The data obtained suggest a stimulatory effect of testosterone on skeletal muscle glycogenesis and an inhibitory effect on glycogenolysis in male rats.
Abstract: Although reports on sex steroids have implicated them as promoting protein synthesis and also providing extra strength to the skeletal muscle, it remains unclear whether sex steroids affect glycoge...
Journal Article•
TL;DR: It is evident that ethanol has an adverse effect on sperm maturation, which may be affected due to the decrease in serum/epididymal testosterone and DHT level and epididymic secretory products.
Abstract: Alcoholics are often associated with fertility disturbances with low sperm count and impaired sperm motility. Spermatozoa attains forward motility and fertilizing capacity during their transit through the epididymis. Epididymal secretory products form a suitable microenvironment, which favors sperm maturation. To study the effects of ethanol on epididymal sperm maturation, ethanol (3 g/kg body weight as 25%, v/v) was given by gastric intubation twice daily for 30 days, and in another group, rats given treatment for 30 days were withdrawn of treatment for a further period of 30 days to assess the reversibility of ethanol-induced changes. Serum and epididymidal testosterone and dihydrotestosterone (DHT), epididymidal tissue and sperm carnitine, acetyl carnitine, glycerylphosphoryl choline (GPC), and sialic acid were studied along with epididymidal sperm count and cauda epididymidal sperm motility. Ethanol treatment significantly reduced the epididymal tissue/sperm carnitine, acetyl carnitine, GPC, and sialic acid, suggesting its adverse effect on these secretory products. Impaired cauda epididymidal sperm motility and fertility (in vivo) of ethanol-treated rats imply the defective sperm maturation. All these changes were reverted back to normalcy after withdrawal of ethanol treatment, indicating the transient effects of ethanol. In conclusion, it is evident that ethanol has an adverse effect on sperm maturation, which may be affected due to the decrease in serum/epididymal testosterone and DHT level and epididymal secretory products.
TL;DR: The results suggest that the anti-inflammatory activity of triterpenes may be due to their anticomplementary activity.
Abstract: Adjuvant arthritis is widely used as an experimental model for rheumatoid arthritis and inflammation. It is useful in the evaluation of anti-inflammatory drugs. Lupeol is a naturally occuring triterpene isolated from Crataeva nurvala stem bark, and its ester lupeol linoleate was synthesized. The effects of lupeol and lupeol linoleate on the development of complement in adjuvant arthritis in rats were studied and compared with those of indomethacin. The effect of lupeol linoleate in reducing the foot-pad thickness and complement activity in arthritic rats was even greater than that of unesterified lupeol and indomethacin. Because complement is highly involved in inflammation, the results suggest that the anti-inflammatory activity of triterpenes may be due to their anticomplementary activity.
TL;DR: Seminal plasma of the mud crab Scylla serrata has been found to possess significant antibacterial activity when tested against some of the commonly occurring marine bacteria like Cytophaga sp.
TL;DR: It was observed that the growth rate in rats was normal and there was no change in blood parameters, which clearly suggested the antitumor potency of Muthu Marunthu in experimentally induced fibrosarcoma in rats.
TL;DR: In this article, a newly modified electrode was prepared by mechanical immobilization of copper hexacyanoferrate (CuHCF) on a graphite electrode, which was characterized by cyclic voltammetric experiments.
Abstract: A newly modified electrode was prepared by mechanical immobilization of copper hexacyanoferrate (CuHCF) on a graphite electrode. The modified electrode was characterized by cyclic voltammetric experiments. The effect of different background electrolytes, pHs and scan rates on the electrochemical behaviour of the electrode has been evaluated. In NH4Cl two reversible redox peaks were observed. The first redox peak corresponding to Cu+/Cu2+ is observed only in this medium. The second redox peak corresponds to the Fe(CN)6
4–/Fe(CN)6
3– couple. Both anodic peaks were used for catalytic oxidation of ascorbic acid. As the anodic current for catalytic oxidation was proportional to the amount of ascorbic acid, an analytical method was developed for the determination of ascorbic acid in commercial samples.
TL;DR: It is concluded that testosterone is effective in both males and females whereas oestradiol was effective only in the females in enhancing skeletal muscle energy metabolism.
Abstract: The main aim of the present study was to test the hypothesis that skeletal muscle ATP concentration, creatine phosphokinase and myokinase enzyme activities are stimulated by the sex steroids in both male and female rats (animals were not subjected to any kind of exercise or any training). To test the hypothesis healthy mature (90–120 days old, weighing about 160–180 g) male and female rats were gonadectomized. Gonadectomized male and female rats were administered with testosterone (Sigma Chemical, St Louis, MO, USA) at a dose of 100 μg (100 g body weight)–1 day–1 for males and 5 μg (100 g body weight)–1day–1 for females for 30 days from day 31 post-castration onwards; and oestradiol at a dose of 5 μg (100 g body weight)–1day–1 for 30 days from day 31 post-castration onwards for both males and females (17β oestradiol, Sigma Chemical Company, St Louis, MO, USA). The ATP content, creatine phosphokinase and myokinase enzyme activities of skeletal muscles were significantly higher than that of skeletal muscles of female control rats. Gonadectomy resulted in a significant decrease in ATP content and creatine phosphokinase myokinase enzyme activities in both male and female rats. Testosterone treatment to gonadectomized male rats brought back the parameters to normalcy whereas the same to the female rats enhanced the enzyme activities and ATP contents to the level of control male rats. Oestradiol treatment to castrated male rats did not bring about any significant alterations whereas the same in gonadectomized female rats brought them back to normalcy. Therefore from the present study it is concluded that testosterone is effective in both males and females whereas oestradiol was effective only in the females in enhancing skeletal muscle energy metabolism.
Journal Article•
TL;DR: The results suggest that eugenol is nontoxic, protective and induces glutathione-S-transferases (GSTs) and thereby it may facilitate the removal of toxic substances from the intestine.
Abstract: The effect of eugenol on the antioxidant status of the rat intestine after short and long term (15 days and 90 days respectively) oral administration of 1000 mg/kg.b.wt (a dosage which has been reported to be highly hepatoprotective) was studied. The level of lipid peroxidation products (TBARS) and the activities of glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) and catalase (CAT) were found to be near normal on eugenol treatment. The level of glutathione (GSH) did not show any change on 15 days of eugenol treatment, but it was increased significantly on 90 day eugenol treatment. The activity of glutathione-S-transferases (GSTs) was increased significantly in both 15 day eugenol treated and 90-day eugenol treated groups. The results suggest that eugenol is nontoxic, protective and induces glutathione-S-transferases (GSTs) and thereby it may facilitate the removal of toxic substances from the intestine.
TL;DR: In this article, a copper hexacyanoferrate (CuHCF) modified graphite electrode prepared by mechanical immobilisation method has been used for the amperometric determination of sulphite, which can be extended for the determination of SO 2 in air after absorbing the pollutant in sodium hydroxide solution.
Abstract: Copper hexacyanoferrate (CuHCF) modified graphite electrode prepared by mechanical immobilisation method has been used for the amperometric determination of sulphite, which can be extended for the determination of SO 2 in air after absorbing the pollutant in sodium hydroxide solution. This method is based upon the electrocatalytic oxidation of sulphite by the modified electrode. The pH of the medium for oxidation should be in the range of 3.5–8.0. The range of determination of SO 2 is from 5.1 to 30.7 ppm. The presence of H 2 S with SO 2 will interfere in the determination. This can be eliminated by precipitating H 2 S as CuS.
TL;DR: An Indian family with multiple consanguineous marriages and a total of four patients with autosomal recessive RP is described and the homozygosity mapping strategy was successfully used and indicated close linkage between the disease locus and patients.
Abstract: Retinitis pigmentosa (RP) is a group of clinically and genetically heterogeneous disorders characterised by night blindness, constriction of visual field, and dystrophic changes of the retina. Previous genetic studies have shown extensive allelic and non-allelic genetic heterogeneity of RP. Here we describe an Indian family with multiple consanguineous marriages and a total of four patients with autosomal recessive (AR) RP. The homozygosity mapping strategy was successfully used and indicated close linkage between the disease locus and D2S380, D2S441, D2S291, and D2S1394 with maximum lod scores between 1.51-3.07 at θ=0.00. The analysis of multiply informative meioses maps the locus (RP28) for ARRP in this family between D1S1337 and D2S286 on 2p11-p15. The involvement of visinin (VSNL1), a promising candidate gene assigned to chromosome 2p by previous studies, has been excluded by the absence of linkage.
Keywords: retinitis pigmentosa; RP28; chromosome 2p11-p15; homozygosity mapping
TL;DR: Light and electron microscopic studies reveal that the spermatophores received by the females during coitus are discernible within the s permathecae until 24 h postmating, demonstrating time-dependent dissolution of the sPermatophore of M. messor within the Spermathecal lumen.
Abstract: In the brachyuran crab Metopograpsus messor mating occurs only among "hard" (intermolt) individuals. Our present light and electron microscopic studies reveal that the spermatophores received by the females during coitus are discernible within the spermathecae until 24 h postmating. The study demonstrates time-dependent dissolution of the spermatophores of M. messor within the spermathecal lumen. The spermatozoa of M. messor were subjected to electron microscopic analysis. In addition to decapod and brachyuran features, the spermatozoa of M. messor display characters typical of the heterotreme-thoracotreme assemblage crabs, such as acrosomal length : width ratio (1.2), and the concentric arrangement of the acrosomal zones around the perforatorium. While the "onion ring" lamellation of the outer acrosome zone represents a typical thoracotreme character, the occurrence of the accessory opercular ring is indicative of its affinity to the GrapsinaeSesarminae subfamilies within the Grapsidae.
TL;DR: The level of collagen was significantly decreased and the excretion of urinary hydroxyproline, hexosamine, hexuronic acid and glycosaminoglycans were increased in arthritic rats.
Abstract: Lysosomal enzymes play important roles in the inflammatory process. The pentacyclic triterpenes, lupeol and lupeol linoleate were administered orally (50 mg/kg) for 8 days to arthritic rats, after 11th day of adjuvant injection. The lysosomal enzymes were significantly increased in arthritic condition, which are involved in the destruction of structural macromolecules in connective tissue and cartilage in rheumatoid arthritis. Hence the level of collagen was significantly decreased and the excretion of urinary hydroxyproline, hexosamine, hexuronic acid and glycosaminoglycans were increased in arthritic rats. Treatment of arthritic rats with triterpenes reversed the above changes, which may be due to stabilization of the lysosomal membrane. Out of the two triterpenes tested, lupeol linoleate showed better ameliorating action than lupeol.
TL;DR: Curcumin, the active constituent of Curcuma longa, enhances the antitumour effect of the widely used anticancer drug cisplatin, when used in combination against fibrosarcoma.
TL;DR: It is shown that high concentrations of NO in the brain suppresses the activity of GABA-T, and the fact that the NOS inhibitor (N(G)-nitro-L-Arg methyl ester (L-NAME) diminished theActivity of NOS and increased the activity for the involvement of NO on GABA-GABAT-T provides support for this.
TL;DR: In this paper, the binding of carboplatin to calf thymus DNA in the presence of thiourea, glutathione, and human breast cancer MCF-7 cell cytoplasmic extracts by measurement of DNA-dependent ethidium bromide fluorescence and atomic absorption spectroscopy was studied.
TL;DR: Glucose-6-phosphatase (G6Pase) and the membrane bound ATPase activities were decreased in CCI 4 treated animals and were completely restored on TAP treatment, thus, suggesting that T AP treatment prevents tissue injury by neutralizing the oxidative stress induced changes.