Showing papers by "University of Madras published in 1991"

Increased degradation of dermal collagen in diabetic rats.

Abstract: The effect of alloxan induced diabetes on the dermal collagen content of albino rats was studied in relation to few lysosomal enzymes. Diabetes decreased the dermal collagen content. The specific activities of the lysosomal enzymes studied in the diabetic rat skin were elevated. It has been established that lysosomal enzymes degrade the connective tissue components. Thus, it may be suggested that the increase in the lysosomal enzymes studied should have facilitated the decrease in dermal collagen content of diabetic rats by increasing the degradation of dermal collagen.

Changes observed in antioxidant system in the blood of postmenopausal women with breast cancer

Abstract: From experimental studies and epidemiological data, it can be inferred that lipid peroxidation is increased in cancer patients. Cases of post-menopausal, untreated women with benign and malignant breast tumours, were compared with their age matched controls in their serum lipid peroxides, antioxidant vitamins (E and C), serum selenium and serum ceruloplasmin. Erythrocyte and its membrane lipid peroxidation and antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase and glutathione-S-transferase) levels were also analyzed. Significant increase in circulating lipid peroxides, ceruloplasmin and significant decrease in antioxidant vitamins and selenium were observed in breast cancer women. The erythrocyte and its membrane lipid peroxidation was increased significantly and severe impairment of antioxidant potential was observed in breast cancer women.

Studies on the changes in plasma lipids and lipoproteins in patients with benign and malignant breast cancer.

Abstract: Experimental studies and epidemiological data suggest that, high fat diet increases the risk of developing breast cancer, both in animal and in human population. Cases of postmenopausal, untreated women with malignant and benign breast tumors, were compared for their age, body weight, plasma lipid fractions and lipoproteins. There was a significant increase in body weight, total plasma lipids, total cholesterol, LDL--cholesterol, VLDL--cholesterol, phospholipids, triacylglycerols, free fatty acids in malignant breast cancer patients. HDL--cholesterol had been significantly decreased in benign and malignant patients when compared with the control subjects.

Geology, Petrography and Systematic Stratigraphy of Pre-Ariyalur Sequence in Tiruchirapaui District, Tamil Nadu, India

Abstract: A new litho unit-Terani Formation is proposed. The lower part of the Uttatur Formation is found to be homotaxially equivalent to the Dalmiapuram Formation. A new geological map based on these units is presented.

Antitumor effect of echitamine chloride on methylcholonthrene induced fibrosarcoma in rats.

Abstract: Echitamine chloride a plant alkaloid from Alstonia scholaris has been used to examine the anticancer effects on methylcholanthrene-induced fibrosarcoma. Echitamine chloride dissolved in saline (10 mg/kg body weight) and injected subcutaneously for 20 days in fibrosarcoma rats has exhibited significant regression in tumor growth. The altered activities of plasma and liver transaminases and gamma-glutamyl transpeptidase and lipid peroxidation in fibrosarcoma have been corrected to near normal after echitamine chloride treatment. The decreased liver glutathione content and the lowered activities of glutathione peroxidase, superoxide dismutase and catalase have also been reversed to near normals after echitamine chloride treatment.

Biofouling and its control in a tropical coastal power station: A case study

Abstract: Macrofouling in the cooling circuits of coastal nuclear power stations is an important problem from the operational and safety viewpoints. However, comprehensive studies on settlement, biomass build‐up and response of settled organisms to control measures are very few. This paper presents data on the biofouling problems encountered in the precondenser section of the cooling circuit of a tropical coastal power station and the control measures adopted to alleviate them. In the Madras Atomic Power Station, development of severe, mussel‐dominated biofouling was noticed in the cooling water intake tunnel, in spite of intermittent chlorination used as a fouling control measure, resulting in serious pressure drop in the cooling water circuits. Switching over to shock dose chlorination, followed by continuous low dose chlorination helped removal of a large quantity of sessile biomass from the tunnel, leading to satisfactory flow performance. The data also indicate the effectiveness of continuous low level chlorin...

Molecular structure, polymorphism, and toxicity of lantadene a, the pentacyclic triterpenoid from the hepatotoxic plant Lantana camara

Abstract: Lantadene A (22 beta-angeloyloxy-3-oxo-olean-12-en-28-oic acid), a pentacyclic triterpenoid compound from lantana (Lantana camara) leaves has been obtained in two polymorphic forms I and II. Form I had white, fluffy, and rod-shaped uniform crystals. Form II particles were irregular, shining, and polyhedral. The two forms differed in melting behavior. The powder x-ray diffraction of form I showed sharp peaks whereas from II did not contain distinct peaks. From single-crystal three-dimensional x-ray structure determination, the molecular structure of form I has been established. A/B and B/C rings of the molecule are trans fused while D/E rings are cis fused. The packing of the molecule is stabilized by hydrogen bonding. Form I of lantadene A was non-toxic to guinea pigs on oral administration. Form II induced ictericity and toxicity associated with decrease in feed intake and fecal output, hepatomegaly, increase in plasma bilirubin, and acid phosphatase activity.

Methionine feeding prevents kidney stone deposition by restoration of free radical mediated changes in experimental rat urolithiasis.

Abstract: Feeding calculi producing diet (CPD) to rats for 4 weeks produced calcium oxalate stones deposition. Supplementation of methionine to CPD (m-CPD) prevented the stone deposition. However the urine pH and excretion of oxalate and calcium in m-CPD-fed rats was still as high as in CPD-fed groups compared to that of the control group. The CPD-fed rats exhibited an increase in liver oxalate synthesizing enzymes and glycolic acid oxidase (GAO) and lactate dehydrogenase (LDH), and these activities were not restored in m-CPD-fed rats. Similarly, the elevated LDH activity and oxalate concentration observed in the kidney of CPD-fed rats were not restored by methionine supplementation. Kidney sub-cellular fractions of CPD-fed rats showed increased susceptibility for lipid peroxidation in presence of iron, ascorbate, and t-butyl hydroperoxide. Antioxidant enzyme activities of superoxide dismutase (SOD), catalase, and glutathione peroxidase and antioxidant concentrations of reduced glutathione, total thiols, ascorbic acid, and vitamin E were significantly decreased, while the xanthine oxidase activity and concentrations of hydroxyl radical, diene conjugates, and hydroperoxides were significantly increased in CPD-fed rats. The susceptibility to lipid peroxidation, activities of antioxidant enzymes, and the concentration of antioxidants were normalized in m-CPD—fed rats, thus suggesting that methionine feeding prevents the stone formation by neutralizing the free radical induced changes.

Estimation of Storativity from Recovery Data

Abstract: In estimating aquifer parameters from pumping test data, it is often found advantageous to use recovery, rather than drawdown, measurements. An equation, derived from Cooper-Jacob's (1946), is suggested for estimating storativity using residual drawdown measurements from an observation well.

Distribution of vesicular-arbuscular mycorrhizal fungi in coal, lignite, and calcite mine spoils of India

Abstract: We assessed vesicular-arbuscular mycorrhizal (VAM) fungi in coal, lignite, and calcite mine spoils. The level of VAM fungal infection and the population of VAM species in plants on the coal-waste sites were similar to those in plants on the calcite mine spoil. The plants on the coal-waste sites and their associated VAM fungi included Tephrosia purpurea (L.) Pers. with Glomus heterosporum and Sclerocystis microcarpus and Euphorbia hirta L. with G. botryoides and G. ambisporum. The recently revegetated lignite mine spoil supported Eragrostis sp. with G. globiferum, while the oldest revegetated lignite mine spoil supported Cocos nucifera L. with Scutellospora aurigloba and G. aggregatum, and Albizia lebbeck (L.) Benth. with Scutellospora dipapillosa and G. tenue. In the calcite mine spoil, roots of Mukia maderaspatana (L.) M. Romer with Sclerocystis sinuosa, G. dimorphicum, G. heterosporum and G. ambisporum and Datura metal L. with G. pustulatum and G. pulvinatum were found. The level of VAM infection and the population of VAM species in the oldest revegetated site (lignite mine spoil) were comparable with those in the coal-waste and calcite mine-spoil sites.

Effect of oral methionine and vitamin e on blood lipid peroxidation in vitamin b6 deficient rats

Abstract: Lipid peroxidation in blood of vitamin B6 deficient rats was significantly increased when compared to pair-fed controls. The observed increased lipid peroxidation in vitamin B6 deficiency was correlated with high levels of lipids, metal ions and low levels of antioxidants, alpha-tocopherol, ascorbic acid and reduced GSH. Supplementation of methionine or vitamin E along with the vitamin B6 deficient diet restored the levels of antioxidants to near normal and also protected against oxidative stress. However plasma TBARS level as well as total lipids were still elevated in M-B6 diet fed rats and normalized in E-B6-d rats.

Biochemistry of seminal secretions of the crab Scylla serrata with reference to sperm metabolism and storage in the female.

Abstract: Biochemical studies on the male reproductive tissues and seminal secretions have been made with reference to sperm metabolism and different stages of maturity in the crab Scylla serrata. The results reveal that the seminal plasma and spermatophores are rich in protein, carbohydrate, and lipid. In general, organic components of spermatophores are considerably higher than those of seminal plasma. Enzyme studies show that the succinate dehydrogenase (SDH) activity is very low, whereas fumarate reductase (FR) and lactate dehydrogenase (LDH) exhibit high activity. Electrophoretic studies on LDH show that, in addition to the occurrence of a sperm-specific fraction, LDHx, the M-type subunits are predominant in the mature spermatophores. These results from enzyme studies suggest that sperm metabolism is mainly anaerobic, utilizing the carbohydrates as substrates. The results for maturational changes reveal that the male reproductive tissues and their secretions contain lesser quantity of organic components in the immature crabs; as the maturity proceeds, there is not only concentration of organic substances but also an increase in the size of spermatophores. The concentration of biochemical constituents is highest in the proximal vas deferens (PVD), suggesting that the granular seminal plasma as well as the sperm-agglutinating substance and spermatophoric wall are secreted in this region. The spermatheca of the unmated female crabs are poor in organic constitutents. After mating, their contents are enriched by organic substances derived from contributions of the seminal substances. During sperm storage in the spermatheca, only the carbohydrates decline steeply. A low activity of SDH, but a moderate level of LDH and a high level of FR activity, is recorded in the spermathecal content of mated crabs, providing further evidence for anaerobic metabolism of sperm during storage in female. A sharp fall in the stored carbohydrates constitutes further evidence in this regard.

Lipid peroxidation in liver of vitamin B-6 deficient rats

Abstract: Vitamin B-6 deficient diet fed rat showed increased lipid peroxidation reactions in liver when compared to that of control. Liver homogenate of vitamin B-6 deficient rats showed enhanced susceptibility to lipid peroxidation upon incubation with NADPH or ascorbate or t-butyl hydroperoxide. Vitamin B-6 deficient liver showed increased levels of lipids, oxalate, calcium, iron, and copper, and decreased levels of antioxidants, ascorbic acid, α-tocopherol, reduced glutathione, total thiol groups, and antioxidant enzymes, glutathione peroxidase, catalase, and glucose 6-phosphate dehydrogenase. Further, vitamin B-6 deficient liver showed enhanced level of hydroxyl radicals and hydroperoxides when compared to that of control liver. The decreased antioxidant protection against free radicals may have led to increased levels of hydroxyl radicals and hydroperoxides which in turn may have led to increased levels of diene conjugates, thiobarbutric acid reactive substances, and lipofuscin-like pigments in liver homogenate. These observations may be an indirect secondary effect of the general disruption of metabolism associated with vitamin B-6 deficiency.

Role of prolactin on Leydig, Sertoli and germ cellular neutral lipids in bonnet monkeys, Macaca radiata.

Abstract: To elucidate the specific influence of prolactin on neutral lipids in Leydig, Sertoli and germ cell compartments of the testis in immature and mature monkeys, the present study was carried out by injecting ovine prolactin (oPRL) (1 mg/kg body weight/twice daily for 10 days ip), to both age groups. Similarly, bromocryptine (an ergot alkaloid which inhibits prolactin secretion) was given to other sets of immature and mature monkeys (1 mg/kg body weight/twice daily for 10 days ip) to induce hypoprolactinemia. It was observed that after oPRL administration the total lipid accumulated in the germ cells of immature and mature monkeys. Total lipid was markedly decreased in the Leydig cells of mature monkeys only. But no such influence of PRL was evident in the Leydig cells of immature monkeys, suggesting an age-dependent effect of PRL on the Leydig cells. The increase in total lipid in the germ cells following PRL treatment was contributed by mono, di- and triacyl glycerols and free cholesterol. However, an opposite effect of PRL was evident in the Leydig cells of mature monkeys, where the cholesterols and glyceride fractions registered a decrease. The reduced cholesterol fractions in the Leydig cells following PRL treatment suggests the utilization of cholesterol for steroidogenesis. Sertoli cells were found to be comparatively resistant to change in PRL status. Bromocryptine treatment brought about the opposite effect of PRL in almost all parameters studied in both immature and mature monkeys. In general, these findings with prolactin suggests that PRL has a specific and definite influence on testicular neutral lipids and the response of different cellular compartments was found to vary.

Effect of diabetes mellitus on epididymal enzymes of adult rats.

Abstract: Diabetes mellitus caused significant reduction in serum testosterone and accessory sex glands weight. The sperm content of epididymal regions also decreased. Among the epididymal regions, the cauda epididymidal tissue alone showed significant reduction in Na(+)-K+ ATPase activity. However, Mg2+ ATPase activity was lowered in caput epididymidis only. Specific activity of Ca2+ ATPase significantly decreased in caput and cauda epididymides. All three ATPases decreased significantly in caput epididymidal spermatozoa leaving cauda epididymidal spermatozoa unaffected. Specific activity of alkaline phosphatase was suppressed in caput epididymidis and in the spermatozoa collected from caput and cauda epididymides, while the acid phosphatase was unaffected. In general, the results are suggestive of definite influence of diabetes on epididymal phosphatases which is region specific. Diabetes induced decrease in phosphatases may have an impact on secretory and absorptive functions of epididymis and thus on sperm maturation.

Induction of oxalate binding by lipid peroxidation in rat kidney mitochondria.

Abstract: Enhanced oxalate binding (150-180% of control) was observed in kidney, liver, brain and heart, after subjecting them to lipid peroxidation in presence of iron. Kidney mitochondrial oxalate binding was stimulated by different promoters, and the order of stimulation was Fe2+ greater than t-BH greater than ascorbic acid greater than Fe3+ greater than H2O2. Oxalate binding was maximum when iron concentration was between 1-2 mM. The iron-induced oxalate binding was inhibited by reduced glutathione, beta-mercaptoethanol, alpha-tocopherol and hydroxyl ion scavengers, histidine and mannitol. Catalase inhibited both Fe(2+)-H2O2 induced oxalate binding and lipid peroxidation reactions, suggesting that the induced oxalate binding in mitochondria was mediated through the hydroxyl radical reaction mechanism.

Thermodynamical model for proton spin

Abstract: The spin content of the proton, is studied in the thermodynamical model of a nucleon. In this study, the different ingredients and their contributions to the spin are studied. The chemical potentials of constituent quarks, spin contributions coming from valence quarks and asymmetries are calculated and compared with the available data. We find that this statistical model with number conservation of valence quarks reproduces the naive quark model prediction for the spin content of the proton.

Utilization of catechin and its metabolites by Bradyrhizobium japonicum.

Abstract: Catechin, a condensed tannin was utilized as sole carbon source by Bradyrhizobium japonicum. Protocatechuic acid, phloroglucinolcarboxylic acid, phloroglucinol, resorcinol and hydroxyquinol were identified as intermediates of catechin degradation. The aromatic substrates favoured good growth up to 5 or 10 mM: . B. japonicum tolerated up to 50 mM: catechin and phloroglucinolcarboxylic acid, 40 mM: phloroglucinol and resorcinol, 30mM: protocatechuic acid and 10 mM: hydroxyquinol. Catechin-induced cells oxidized catechin more rapidly than uninduced cells. The two final ring compounds of the catechin catabolic pathway, protocatechuic acid and hydroxyquinol, were oxidized differentially. The enzymes of the catechin degradative pathway were inducible in B. japonicum.

Degradation of lignin and lignin derivatives by Acinetobacter sp.

Abstract: An Acinetobacter sp. utilized 2-methoxy-4-formylphenoxyacetic acid, dehydrodivanillyl alcohol, dehydrodiisoeugenol and conidendrin as sole carbon source. It also degraded 14 C-labelled DHP lignin and teakwood lignin. Vanillic acid, protocatechuic acid and catechol were separated from 2-methoxy- 4-formylphenoxyacetic acid grown cultures. Both protocatechuic acid and catechol were formed from dehydrodivanillyl alcohol, dehydrodiisoeugenol and conidendrin. On the dimeric lignin model substances this Acinetobacter sp. produced protocatechuate 3,4-dioxygenase and catechol 1,2-dioxygenase

On weak spectral synthesis

Abstract: Weak spectral synthesis fails in the group algebra and the generalised group algebra of any non compact locally compact abelian group and also in the Fourier algebra of any infinite compact Lie group.

Effect of subacute administration of isoniazid and pyridoxine on lipids in plasma, liver and adipose tissues in the rabbit.

Abstract: The effect of subacute intraperitoneal administration of Isoniazid (INH) on various lipid parameters was studied in liver and adipose tissue in addition to plasma. In the liver, its effect on various phospholipid fractions was also assessed. The changes in lipid profile reflected INH-induced hepatic steatosis. While pyridoxine alone did not alter any of these lipid parameters, its concurrent administration with INH prevented almost all the INH-induced lipid changes. The enhanced lipid mobilization into liver, and a fall in phosphatidylcholine with a concomitant rise in phosphatidylethanolamine in liver impeding lipoprotein synthesis, might be responsible for the hepatic steatosis. Pyridoxal, a pyridoxine metabolite, might have trapped the primary amine functional group of acetylhydrazine and thus prevented the steatosis.

Biochemical studies on the antidiarrhoeal effects of Cauvery-100, an ayurvedic formulation, in rats.

Abstract: Diarrhoea is a common gastrointestinal disorder which is a state of fluid and ion loss from the gut. Cauvery-100, an Ayurvedic formulation has been used in this study for the treatment of diarrhoea. Diarrhoea was induced in experimental rats by oral administration of castor oil. The increased gastrointestinal motility in diarrhoea was brought back to near normal levels on the treatment of Cauvery-100. The activities of the enzymes alkaline phosphatase, total ATPase and Na+,K(+)-ATPase were decreased in the diarrhoeal group and was brought back to near normal levels in the treated group. The serum levels of sodium and potassium were decreased in the diarrhoeal group and brought back to normal levels in the treated group. Prior treatment of the drug Cauvery-100 did not induce diarrhoea on administration of castor oil, suggesting the protective influence of the drug on the gastrointestinal tract.

Toxic effect of morphine and the antagonistic role of naloxone on isolated rat hepatocytes.

Abstract: Isolated rat hepatocytes when incubated with various concentrations of morphine exhibited a marked decrease in the level of glutathione and resulted in cell death. The formation of electrophilic intermediates make the cell more susceptible to peroxidative attack, which is reflected by the increase in thiobarbituric acid reactant material as well as lipid fluorescence. Pretreatment of cells with naloxone blocked the morphine induced damage and itself has no cytotoxic effects on the cells.

Effect of alpha-tocopherol on doxorubicin-induced changes in rat liver and heart microsomes.

Abstract: Rats were treated with doxorubicin (2.5 mg/kg body wt, iv) once a week for 8 weeks. Alpha-Tocopherol (400 mg/kg body wt/day) was co-administered orally for 2 months. Cytochrome-P450 (Cyt-P450) and Cytochrome-b5 (Cyt-b5) levels decreased significantly in doxorubicin treated rats. Significant decreases were observed in glucose-6-phosphatase, Cyt-P450 and Cyt-b5 reductase activities. In vitro lipid peroxidation study showed that alpha-tocopherol significantly minimises the lipid peroxide formation by doxorubicin. There was a significant change in microsomal cholesterol and phospholipid levels. Alpha-Tocopherol co-administration reduced the alterations in xenobiotic metabolising system and microsomal lipid levels. The results were discussed with reference to drug metabolising enzymes, lipid peroxidation and antioxidant nature of alpha-tocopherol.

Studies on the cross stand hydrogen bonds in DNA double helices.

Abstract: A systematic analysis has been carried out to examine all the stereochemically possible bifurcated hydrogen bonds including those of cross strand type between propeller twisted base pairs in DNA double helices by stereochemical considerations involving base pairs alone and by molecular mechanics studies on dimer and trimer duplexes. The results show that there are limited number of combinations of adjacent base pairs that would facilitate bifurcated cross-strand hydrogen bond (CSH). B-type helices concomitant with negative propeller twist seem to be more favored for the occurrence of CSH than canonical A-type helices because of slide in the latter. The results also demonstrate that helices with appropriate sequences may possess continuous run of these propeller twist driven cross strand hydrogen bonds indicating that they may in fact be considered as yet another general structural feature of DNA helices.