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Showing papers by "University of Madras published in 1994"


Journal ArticleDOI
TL;DR: Findings strongly suggest that all the three sequences adopt an intramolecular i-motif structure for KRC6, a critical functional stretch of the c-ki-ras promoter proto-oncogene, besides the human telomeric sequence HTC4, may be suggestive of larger significance in the functioning of DNA.
Abstract: The structural behaviour of repetitive cytosine DNA is examined in the oligodeoxynucleotide sequences of (CCCTAA)3CCCT (HTC4), GC(TCCC)3TCCT(TCCC)3 (KRC6) and the methylated (CCCT)3TCCT(CCCT)3C (KRM6) by circular dichroism (CD), gel electrophoresis (PAGE), and ultra violet (UV) absorbance studies. All the three sequences exhibit a pH-induced cooperative structural transition as monitored by CD. An intense positive CD band around 285 nm develops on lowering the pH from 8 to slightly acidic condition, indicative of the formation of base pairs between protonated cytosines. The oligomers are found to melt in a fully reversible and cooperative fashion, with a melting temperature (Tm) of around 50 degrees C at pH 5.5. The melting temperatures are independent from DNA concentration, indicative of an intramolecular process involved in the structural formation. PAGE experiments performed with 32P-labeled samples as well as with normal staining procedures show a predominantly single band migration for all the three oligomers suggestive of a unimolecular structure. From pH titrations the number of protons required for generating the structures formed by HTC4, KRC6 and KRM6 results to be around six. These findings strongly suggest that all the three sequences adopt an intramolecular i-motif structure. The demonstration of i-motif structure for KRC6, a critical functional stretch of the c-ki-ras promoter proto-oncogene, besides the human telomeric sequence HTC4, may be suggestive of larger significance in the functioning of DNA.

177 citations


Journal ArticleDOI
TL;DR: In vitro [3H]thymidine incorporation showed the inhibition of DNA synthesis in fibrosarcoma cells by the flavonoids, and Elevated levels of lipid peroxides, cytochrome P450 and decreased activity of glutathione-S-transferase (GST) were observed in the tumor bearing animals.

176 citations


Journal ArticleDOI
TL;DR: Embelin, a plant-based benzoquinone derivative, has been found to exhibit significant antitumor activity in methylcholanthrene-induced fibrosarcoma in albino rats besides enhancing their survival time and has an appreciable action on pain and inflammation.
Abstract: Embelin, a plant-based benzoquinone derivative, has been found to exhibit significant antitumor activity in methylcholan-threne-induced fibrosarcoma in albino rats besides enhancing their survival tim

162 citations


Journal ArticleDOI
01 Feb 1994-Cancer
TL;DR: The purpose of the study was to evaluate the effects of tamoxifen on plasma lipid and lipoprotein profiles in postmenopausal Indian women who were disease‐free after primary treatment for breast cancer.
Abstract: Background. Adjuvant tamoxifen therapy is given to large and increasing numbers of women with early-stage breast cancer. The effects of this drug on plasma lipids and lipoprotein profiles are important, because cardiovascular disease also develops over time in a large percentage of tamoxifen-treated postmenopausal women. The purpose of the study was to evaluate the effects of tamoxifen on plasma lipid and lipoprotein profiles in postmenopausal Indian women who were disease-free after primary treatment for breast cancer. Methods. A short-term evaluation of 6 months of tamoxifen therapy (10 mg twice a day) in 45 postmenopausal women was conducted. The plasma lipids and lipoprotein levels were evaluated before and after 3 and 6 months of tamoxifen treatment. Results. At 3 and 6 months' evaluation, patients receiving tamoxifen showed significantly decreased levels of total cholesterol, free cholesterol, and low-density lipoprotein cholesterol (P < 0.001 for each) and increased levels of plasma triglycerides, free fatty acids, very low density lipoprotein cholesterol, and high-density lipoprotein cholesterol. Conclusion. The results suggest that tamoxifen therapy benefits postmenopausal patients with breast cancer, with likely reduction in the risk of cardiovascular disease. Cancer 1994: 73659-63.

86 citations


Journal ArticleDOI
01 Jul 1994-Cancer
TL;DR: The purpose of this study was to understand the rate of lipid peroxidation and the status of antioxidants in tamoxifen‐treated postmenopausal women with breast cancer.
Abstract: Background. Current evidence clearly indicates that free radicals play a prominent role in the incidence and development of breast cancer. Available literature suggests that tamoxifen is a potent suppressor of lipid peroxide formation in both animal and human systems. The purpose of this study was to understand the rate of lipid peroxidation and the status of antioxidants in tamoxifen-treated postmenopausal women with breast cancer. Methods. A short term evaluation of 6 months' tamoxifen therapy (10 mg twice a day) in 64 postmeno-pausal women was conducted. The rate of serum lipid peroxidation and the status of enzymic and nonenzymic antioxidants were evaluated before and after 3 and 6 months' tamoxifen treatment. Results. At 3 and 6 months' evaluation, tamoxifen-treated patients showed a significantly decreased concentration of malondialdehyde (P < 0.001), an end product of lipid peroxidation, and remarkably increased levels of enzymic and nonenzymic antioxidants. In addition to that, the concentrations of serum selenium and vitamins A, C, and E were increased significantly (P < 0.01 for each) in these patients. Conclusion. The results suggest that tamoxifen therapy exerts significant positive effects on the rate of lipid peroxidation and protective systems in postmenopausal women with breast cancer.

69 citations


Journal Article
TL;DR: Analysis of the plasma lipoprotein profile showed that TCR produced remarkable reduction in the increased levels of cholesterol, triglycerides and phospholipids in the low densitylipoprotein (LDL) and very low density lipoprotein fractions in hyperlipidemic rats.
Abstract: Tincture of Crataegus (TCR), an alcoholic extract of the berries of Crataegus oxyacantha, when administered to rats fed a hyperlipidemic diet (HLD), could prevent the elevation in plasma lipid levels. A significant decrease in lipid deposits in liver and aorta was also observed. Analysis of the plasma lipoprotein profile showed that TCR produced remarkable reduction in the increased levels of cholesterol, triglycerides and phospholipids in the low density lipoprotein (LDL) and very low density lipoprotein (VLDL) fractions in hyperlipidemic rats. Histological examination showed severe fatty vacuolation and degeneration of liver of HLD fed rats. TCR administration had an ameliorating effect on these changes. Agarose gel electrophoretic pattern of plasma lipoproteins also indicated that the drug brought down the raised levels of the atherogenic beta-lipoproteins in hyperlipidemic rats.

59 citations


Journal ArticleDOI
TL;DR: It is suggested that the uncompetitive inhibition of this phosphatase by lithium ions may prevent the formation of an enzyme-bound non-isomeric (meso) intermediate, Mg(2+)-inositol 1,3 or 4,6 cyclic monophosphate when this enzyme hydrolyzes its respective isomeric substrates.

55 citations


Journal ArticleDOI
TL;DR: A 10-year human study indicates that the leaf extract can be reliably used as a herbal medicine to treat Pityriasis versicolor and has no side-effects.

54 citations



Journal ArticleDOI
TL;DR: Several characterizing theorems of fuzzy semi-continuity and its relationship with fuzzy continuity are investigated.

48 citations


Journal ArticleDOI
TL;DR: In this paper, the deblocking temperatures were determined by nitrogen estimation, IR, and 1 H-NMR spectroscopy, and the absence of an IR absorption band at 2270 cm -1 confirmed the completion of the reaction between the isocyanate and the blocking agents, whereas the presence of a band at 1075-1150 cm - 1 confirmed the formation of poly(ether urethanes).
Abstract: Phenol-, 2-naphthol-, and 1-nitroso-2-naphthol-blocked toluene diisocyanate (TDI) and isophorone diisocyanate (IPDI) adducts and their polymers with PPG-1000 were prepared and characterized by nitrogen estimation, IR, and 1 H-NMR spectroscopy. The absence of an IR absorption band at 2270 cm -1 confirmed the completion of the reaction between the isocyanate and the blocking agents, whereas the presence of a band at 1075-1150 cm -1 confirmed the formation of poly(ether urethanes). The deblocking temperatures were determined. The thermal stabilities of the 2-naphtol-blocked diisocyanates were less than the phenol-blocked diisocyanates. Dissociation temperature was also reduced by the nitroso group in the blocking agent

Journal ArticleDOI
TL;DR: A reinvestigation of the X-ray crystal structure of malonic acid (C3H4O4) has been made in the light of some observations arising from solid-state 13C NMR studies on this compound as mentioned in this paper.
Abstract: A reinvestigation of the X-ray crystal structure of malonic acid (C3H4O4) has been made in the light of some observations arising from solid-state13C NMR studies on this compound. The unit cell parameters are:a=5.156(1),b=5.341(1),c=8.407(1) A, α=71.48o (2), β=76.12o (2), γ=85.09o (2), space group $$P\bar 1$$ ,Z=2. The structure was solved by direct methods and refined by full-matrix least-squares refinement to a finalR value of 0.038 for 711 unique reflections withl>3σ. The packing of the molecules involves dimeric hydrogen bonded association of each carboxyl group with a centrosymmetrically related neighbor. The angles O−C−O (123.3o and 124.8o, respectively) for the two carboxyl groups agree qualitatively with the values predicted from a linear relationship relating the observed σ22 component of the Carbon-13 NMR chemical shielding tensor for the carboxyl carbon atom to the bond angle O−C−O at the carbon atom.

Journal ArticleDOI
TL;DR: A serotonergic involvement was significant in endosulfan-induced learning impairment and it appeared to be negligible in its memory disrupting action, interpreted as an indication that a motivation deficit and not motor impairment was responsible for the inhibitory action of endos sulfuran on pole-climbing escape and avoidance responses.

Journal ArticleDOI
01 Jul 1994-BJUI
TL;DR: Banana stem extract from the Musaceae family may be a useful agent in the treatment of patients with hyperoxaluric urolithiasis and in the rats treated with aqueous banana stem extract, urinary oxalate excretion was significantly reduced when compared with the controls.
Abstract: Objective To study the effect of banana stem (Family Musaceae) extract on urinary risk factors in an animal model of hyperoxaluria. Materials and methods Thirty male rats were divided into five groups of six rats each. The rats in Group I acted as the control, in Group II rats hyperoxaluria was induced using sodium glycollate, Group III were given aqueous banana stem extract alone, Group IV were given both sodium glycollate and aqueous banana stem extract and Group V were given sodium glycollate alone followed by aqueous banana stem extract. Urine analysis (24 h) was carried out to determine the levels of calcium, phosphorous, oxalate, glycollic acid and glyoxylic acid in each of the five groups. Results In the rats treated with aqueous banana stem extract, urinary oxalate excretion was significantly reduced when compared with the controls. The extract reduced urinary oxalate, glycollic and glyoxylic acid and phosphorus excretion in the hyperoxaluric rats. The extract appeared to have no effect on urinary calcium excretion. Conclusion Banana stem extract from the Musaceae family may be a useful agent in the treatment of patients with hyperoxaluric urolithiasis.

Journal Article
TL;DR: Most of breast cancer patients are treated with CMF, which is a combination of three anticancer agents, cyclophosphamide, methotrexate and 5-fluorouracil, and metabolites of CMF induce lipid peroxidation by inactivating the antioxidant enzymes, thereby rendering the system inefficient in management of the free radical attack.
Abstract: Most of breast cancer patients are treated with CMF, which is a combination of three anticancer agents, cyclophosphamide, methotrexate and 5-fluorouracil. Metabolites of CMF induce lipid peroxidation by inactivating the antioxidant enzymes, thereby rendering the system inefficient in management of the free radical attack. Acrolein and phosphoramide mustard are the metabolites of cyclophosphamide which are among the causative agents which reduce the activity of superoxide dismultase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and glucose-6-phosphate dehydrogenase in erythrocytes of CMF treated breast cancer patients.

Journal ArticleDOI
TL;DR: The tissue level of lipid peroxides and the activity of glutathione-S-transferase were found to be significantly higher than that of normals from stage II onwards, which suggested the impaired antioxidant status in carcinoma of the uterine cervix.

Journal ArticleDOI
TL;DR: 1,3-diphenylnitrilimine generated in situ undergoes 1,3dipolar cycloaddition with C60 to form a diadduct which is characterised by FAB mass spectrum and other spectroscopic techniques.

Journal ArticleDOI
TL;DR: In this article, the pit protection potential for nitrogen-bearing stainless steels was more noble than the corrosion potential indicating the higher repassivation tendency of actively growing pits in these alloys.
Abstract: Potentiodynamic anodic polarization experiments on advanced stainless steels (SS), such as nitrogenbearing type 316L and 317L SS, were carried out in Hank’s solution (8 g NaCl, 0.14 g CaCl2, 0.4 g KC1, 0.35 g NaHCO3, 1 g glucose, 0.1 g NaH2PO4, 0.1 g MgCl2, 0.06 g Na2HPO4 2H2O, 0.06 g MgSO4 7H2O/1000 mL) in order to assess the pitting and crevice corrosion resistance. The results showed a significant improvement in the pitting and crevice corrosion resistance than the commonly used type 316L stainless steel implant material. The corrosion resistance was higher in austenitic stainless steels containing higher amounts of nitrogen. The pit-protection potential for nitrogen-bearing stainless steels was more noble than the corrosion potential indicating the higher repassivation tendency of actively growing pits in these alloys. The accelerated leaching study conducted for the above alloys showed very little tendency for leaching of metal ions, such as iron, chromium, and nickel, at different impressed potentials. This may be due to the enrichment of nitrogen and molybdenum at the passive film and metal interface, which could have impeded the releasing of metal ions through passive film.

Journal ArticleDOI
TL;DR: In this paper, the concepts of fuzzy α-open (α-closed) sets, fuzzy pre- open (pre-closed), fuzzyα-continuous ( pre-Continuous) mappings due to Bin Shahna have been generalized to the fuzzy bitopological setting and some of its basic properties are studied.

Journal ArticleDOI
TL;DR: In this paper, seven hundred fifty-three students from seven cities of India reported: (a) their perception of what people in general believe, practise and prefer (i.e., operative values); (b) their own allocentric and idiocentric orientations; (c) the extent to which they attached importance to other's (over their own) opinions, desires and interests; and (d) their age, gender, caste, class and urban exposure.
Abstract: Seven hundred fifty-three students from seven cities of India reported: (a) their perception of what people in general believe, practise and prefer (i.e., operative values); (b) their own allocentric and idiocentric orientations; (c) the extent to which they attached importance to other's (over their own) opinions, desires and interests; and (d) their age, gender, caste, class and urban exposure.The significant mean differences between the seven sub-samples led to identify three clusters of cities, namely the North, the South and the Central. The North and the South presented a contrast—the former manifesting strong orientations to meet unjustifiable and inconvenient social obligations and to cultivate personalised relationships. The Central cluster showed a differentpattern. The items on which the sub-samples did not differ formed a general factor of collectivism consisting of the themes of familialism, hierarchy and relationship orientation. Collectivism was found to be unrelated to the respondents' rat...

Journal ArticleDOI
TL;DR: A preliminary growth study was conducted with juvenile Oreuchromis mossambicus using a live-food Streptocephalus dichotomus, and experimental fish showed better growth, survival and food conversion ratios, as well as a significant increase in protein, free sugars and protein bound sugars.
Abstract: A preliminary growth study was conducted with juvenile Oreuchromis mossambicus using a live-food Streptocephalus dichotomus. Experimental fish showed better growth, survival and food conversion ratios, as well as a significant increase in protein (12%), free sugars (34.4%) and protein bound sugars (101%). However, there was a decline in the lipid content (-3.99%). Energy budget analysis revealed that about 90% of the consumed energy (as live-food) was assimilated by the experimental fishes. It is likely that the fish used 45% of the total energy assimilated for metabolic activities associated with growth.

Journal ArticleDOI
TL;DR: In this article, the anticarcinogenic activity of α-tocopherol (Vitamin E) was tried in fibrosarcoma induced rats through its antioxidative potential.
Abstract: The anticarcinogenic activity of α-tocopherol (Vitamin E) was tried in fibrosarcoma induced rats through its antioxidative potential. The rate of formation of malondialdehyde (MDA), the end product of lipid peroxidation was analysed in α-tocopherol (400 mg/kg body weight) treated and untreated fibrosarcoma bearing rats with respective controls. The levels of non-enzymic antioxidants like, glutathione and vitamin E, and enzymic antioxidants viz., catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and glutathione-S-transferase (GST) were assayed as well. Significantly increased (p<0.001) level of lipid peroxide was observed with concomitant decreases in the level of enzymic and non-enzymic antioxidants in fibrosarcoma bearing rats when compared with control animals. In α-tocopherol supplemented animals, the corrected level of these parameters were observed likely to near normal values. Thus, α-tocopherol can be accepted to pose first line of defence mechanism against excessively formed reactive species due to impaired antioxidant systems in fibrosarcoma conditions, that cause membrane damage leading to deleterious effects.

Journal ArticleDOI
TL;DR: Bacterial antagonists of both fluorescent and nonfluorescent groups were screened for in-vitro inhibition of the rice sheath blight fungus Rhizoctonai solani Kuhn and chitinase production in the laboratory and there was no correlation between chit inase activity in the antagonists and ShB suppression in the seed-bed or field plots.
Abstract: Bacterial antagonists of both fluorescent and nonfluorescent groups were screened for in-vitro inhibition of the rice sheath blight (ShB) fungus Rhizoctonai solani Kuhn and chitinase production in the laboratory. Twelve percent of the total 1,757 strains screened inhibited R. solani while 31% of the total 1,366 strains tested were positive for chitinase activity. The efficient strains were then evaluated in the field for ShB suppression. Two strains from each of the three seed-bed experiments were chosen for the field test in a hot-spot location. Additional treatments were a Bacillus and validamycin, the fungicide. There was no correlation between chitinase activity in the antagonists and ShB suppression in the seed-bed or field plots. Two most efficient Pseudomonas putida and P. fluorescens strains afforded 68 and 52% ShB suppression while validamycin afforded 27% disease control.

Journal Article
TL;DR: The results confirm drug-induced inhibition of mitochondrial respiration, thereby impairing availability and utilisation of energy.
Abstract: Chloroquine causes an increase in phospholipid and a decrease in cholesterol in liver mitochondria. A significant decrease in the activities of mitochondrial inner membrane enzymes such as NADH dehydrogenase, succinate dehydrogenase and cytochrome c oxidase is observed. Decrease in cytochrome contents and respiratory control ratio, shown by a decrease in state 3(+ADP) and an increase in state 4 (-ADP), implies decreased ATP synthesis following chloroquine administration. The results confirm drug-induced inhibition of mitochondrial respiration, thereby impairing availability and utilisation of energy.

Journal ArticleDOI
TL;DR: In this paper, the Wittig-Horner reaction of the phosphonate esters of 1-benzenesulfonyl-2- bromomethyl-3-substituted indoles with o-nitrobenzaldehydes followed by deoxygenation with triethyl phosphite gave 2,2′-biindolyls.

Journal ArticleDOI
TL;DR: Amrita Bindu is a salt-spice-herbal mixture and was tested for its effect in maintaining antioxidant defense systems in blood and liver when exposed to a carcinogenic nitrosamine, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG).

Journal ArticleDOI
TL;DR: In this article, an attempt was made to prepare Pt/Bi 2 O 3 /RuO 2 (PhC) catalyst and to use it for photocatalytic production of hydrogen from water in the presence of: (i) methyl viologen (MV 2+ ) as an electron relay, (ii) Ru(bpy) 3 2+ as a photosensitizer, or (iii) both (i and λ ⩾ 400 nm).

Journal ArticleDOI
TL;DR: The crystal structure of a dipeptide L‐leucyl–L‐leucine (C12H24N2O3) has been determined and the trans peptide unit shows substantial degree of non‐planarity.
Abstract: The crystal structure of a dipeptide L-leucyl-L-leucine (C12H24N2O3) has been determined. The crystals are monoclinic, space group P2(1), with a = 5.434(4) A, b = 15.712(7) A, c = 11.275(2) A, beta = 100.41(1) degrees, and Z = 2. The crystals contain one molecule of dimethyl sulfoxide (DMSO) as solvent of crystallization for each dipeptide molecule. The structure has been solved by direct methods and refined to a final R index of 0.059 for 920 reflections (sin theta/lambda or = 2 sigma (I). The trans peptide unit shows substantial degree of non-planarity (delta omega = 14 degrees). The peptide backbone adopts an extended conformation with torsion angles of psi 1 = 138(1) degrees, omega 1 = 166(1) degrees, phi 2 = -149.3(7) degrees, psi 21 = 164.2(7) degrees, and psi 22 = -15(1) degrees. For the first leucyl residue, the side-chain conformation is specified by the torsion angles 1 chi 1 = 176.7(7) degrees, 1 chi 21 = 62(1) degrees, 1 chi 22 = -177.4(8) degrees; the second leucyl residue adopts a sterically unfavorable conformation with 2 chi 1 = 61(1) degrees, 2 chi 21 = 97(1) degrees, and 2 chi 22 = -151(1) degrees. The packing involves head-to-tail interaction of peptide molecules and segregation of polar and nonpolar regions. The DMSO molecule is strongly hydrogen bonded to the terminal NH3+ group.

Journal ArticleDOI
TL;DR: In this paper, a 3-year study was carried out in the Bay of Bengal off Madras in order to understand the influence of physical and chemical variables on the occurrence, abundance and productivity of its phytoplankton.
Abstract: A 3 year study (1986–1989) was carried out in the Bay of Bengal off Madras in order to understand the influence of physical and chemical variables on the occurrence, abundance and productivity of its phytoplankton. Biochemical oxygen demand and nutrient concentrations were highest near the mouth of river Cooum. Pigments and net primary production in nearshore waters varied between 4.1 and 1113 C mg m−3 h−1, while in offshore waters the maximum was only 201 mg C m−3 h−1. Multiple regression analysis with net photosynthesis as the dependent variable and other variates as the independent variables revealed that nutrients did not account for much variation in net photosynthesis in nearshore stations but contributed significantly to variation in offshore station. Analyses of seawater collected during two cruises in coastal waters at 18–22° N latitude revealed that nitrogen was low in comparison to phosphorus and could be limiting primary production in the surface waters of the Bay.

Journal ArticleDOI
TL;DR: In this article, a thermodynamic bag model is proposed to study the parton distribution functions and nucleon structure functions in the deep inelastic scattering (DIS) of leptons on nucleons.
Abstract: A thermodynamical bag model is proposed to study the parton distribution functions and nucleon structure functions in the deep inelastic scattering (DIS) of leptons on nucleons. Equations of state for the thermodynamical bag are deduced and solved self-consistently. The theory explains all the observed features in DIS and gives a good fit to the experimental data.