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Biomedical subjects

A Sharma

Publications and source records attributed to A Sharma.

At least 793 records · Page 44Linked to original sources
PubMed1990

Hepatoprotective activity of andrographolide against galactosamine & paracetamol intoxication in rats.

Hepatoprotective effect of andrographolide (the major active diterpenoid lactone of the plant Andrographis paniculata) was studied on acute hepatitis induced in rats by single dose of galactosamine (800 mg/kg, ip)/paracetamol (3g/kg, po). Hepatoprotective activity was monitored by estimating the serum transaminases (GOT and GPT), alkaline phosphatase and bilirubin in serum, hepatic triglycerides, and by histopathological changes in the livers of experimental rats. Pre-treatment and/or post-treatment of rats at different time intervals with different doses of andrographolide in the two experimental models of hepatotoxicity showed that treatment of rats with 400 mg/kg, ip or 800 mg/kg, po, 48, 24 and 2 h before galactosamine administration or with 200 mg/kg, ip, 1, 4 and 7 h after paracetamol challenge leads to complete normalisation of toxin-induced increase in the levels of all the five biochemical parameters, and significantly ameliorates toxin-induced histopathological changes in the livers of experimental rats. The results confirmed the in vivo hepatoprotective effect of andrographolide against galactosamine or paracetamol-induced hepatotoxicity in rats. Since the protective effect of andrographolide was observed in two types of intoxication, which are very different in their primary mechanism of inducing hepatotoxicity, it is suggested that protective mechanisms of andrographolide which are not specific to galactosamine or paracetamol toxicity may be responsible for the hepatoprotective activity of the compound.

Acetaminophen↗
PubMed1990

Concurrent analysis of plasma retinol and alpha-tocopherol by isocratic HPLC.

A simple, rapid and reliable method is described for simultaneous determination of plasma retinol and alpha-tocopherol. Plasma is deprotenized with 100% ethanol which contains retinyl acetate as internal standard and later extracted with HPLC grade n-hexane. The evaporated organic layer is reconstituted with methanol; diethyl ether (75:25 v/v) and injected onto a 250 x 4.6 mm column of zorbax CIS ODS C18 at a 1.5 ml/min flow rate. The system is monitored at 280 nm for both retinol and alpha-tocopherol. Intrabatch CVs were 3.9% for retinol and 1.8% for alpha-tocopherol respectively. Interbatch CVs over a 8-12 weeks period were about 9.48% for retinol and 6.7% for alpha-tocopherol. Our results agree well with those of retinol and alpha-tocopherol in quality control samples. This method should prove useful for routine analysis in clinical and epidemiological work.

Chromatography, High Pressure Liquid↗
PubMed1990

Flocculation of serum lipoproteins with cyclodextrins: application to assay of hyperlipidemic serum.

We describe the complexation of isolated and native lipoproteins by natural macrocyclic polymers of glucose ("cyclodextrins"). Treatment of serum with cyclodextrin produces an immediate flocculation of the lipoproteins. The formation of cyclodextrin-lipoprotein complexes was evident on agarose electrophoresis gels. The concentration-dependent ability of alpha-cyclodextrin to precipitate chylomicrons and very-low-, low-, and high-density lipoproteins was used for clarifying lipemic serum. Results for normal and lipemic patients' specimens for some routinely measured analytes showed a good correlation between cyclodextrin treatment and ultracentrifugation. Unlike the use of organic solvents or ultracentrifugation, the proposed system provides a simple, mild, non-hazardous, and effective means for removing interfering lipid particles from biological specimens.

Chemical Precipitation↗
PubMed1990

Modifying effects of calcium on aluminum induced toxicity in mammalian tissues in vivo.

Oral administration of calcium, following by aluminium or together with Al, has been found to counteract the toxic effects of the latter metal as observed in histological preparations of liver, brain, kidney, and bone of laboratory albino rats. No such improvement was seen if Ca was administered after Al. The protection afforded by Ca against Al toxicity may be due to the previous occupation by Ca ions of the binding sites of Al ions in the affected organs.

Aluminum↗
PubMed1990

Inhibition of lipoprotein lipase activity by high density lipoprotein & apolipoproteins C, E & A in rhesus monkeys.

Experiments were conducted to study the effects of high density lipoprotein (HDL) and apolipoproteins C, E, and A on lipoprotein lipase activity in rhesus monkeys. The lipoprotein lipase activity was inhibited up to 32 +/- 6 per cent by monkey HDL. This inhibition was considerably decreased (2 +/- 0.02%) by using apolipoprotein-poor HDL. Apolipoproteins C and E inhibited the hydrolysis of activated intralipid by monkey lipoprotein lipase to a maximum of 83 +/- 7 and 57 +/- 5 per cent respectively. Apolipoprotein A produced little inhibition of lipoprotein lipase activity. The results of these studies demonstrate that HDL and apolipoproteins compete with the substrate for the binding to lipoprotein lipase in rhesus monkeys.

Animals↗
PubMed1989

Intracellular hydrolases of Aspergillus parasiticus and Aspergillus flavus.

When the distribution profile of hydrolases in mycelial homogenates and culture filtrates of A. parasiticus and A. flavus was examined, six hydrolytic enzymes viz. N-acetyl-beta-glucosaminidase, aryl sulfatase, alkaline proteinase, cathepsin B, cathepsin D and aminopeptidase were detected in homogenate. The culture filtrates were devoid of any activity of these enzymes. The enzyme levels varied with the stage of incubation. The most abundant fungal exopeptidase showing preference for basic amino acid naphthylamides seems to be an aminopeptidase B. Incorporation of CEPA, an ethylene generating compound, stimulated the amino peptidase activity in the mycelium but inhibited the enzyme in vitro. The enzyme was also inhibited by different aflatoxins to varying degree. While aminopeptidase B was located intracellularly, a non-dialysable, heat-stable inhibitor of the enzyme was found to be secreted in the culture filtrate. This peptide inhibitor was however ineffective on the other enzymes.

Aspergillus↗
PubMed1989

Sister chromatid exchanges induced by tertiary butyl hydroquinone in bone marrow cells of mice.

Tertiary butyl hydroquinone (TBHQ)--a phenolic antioxidant, was evaluated by assessing the induction of sister chromatid exchanges (SCEs) in bone marrow metaphase cells of mice. Six concentrations, 0.5, 2, 20, 50, 100, and 200 mg/kg, of TBHQ were injected intraperitoneally. A positive dose-response effect in the SCE frequency was observed using the Cochran-Armitage trend test. Two mg/kg of TBHQ was found to be the minimum effective dose. Study of the cell-cycle kinetics showed a delay in cell cycle induced by the higher concentrations of TBHQ. Thus, TBHQ was found to be a DNA damage-inducing agent and also a cytotoxic chemical in vivo in mice.

Animals↗
PubMed1989

The relation of rural alcoholism to farm economy.

Several studies have suggested an association between the farm crisis of the 1980's and the increase in mental health problems in rural America. A stress hypothesis for alcoholism would indeed predict such an association. The study presented herein examines the rate of new referrals for treatment of alcohol abuse and/or dependence to state-funded agencies in Nebraska. Between mid-1978 and mid-1986, the rate of subjects seeking treatment grew steadily, paralleling an increase in both population and available treatment programs. Yet, the total number of farmers seeking treatment peaked around 1982 and declined steadily thereafter, outpacing any change in the total number of farmers in the state. Possible interpretations of these findings are discussed.

Adult↗
PubMed1989

Effects of copper on mammalian cell components.

Both deficiency and excess of copper induce toxic effects on mammalian cell systems in vivo and in vitro. The effects can be related to the affinities of Cu(II) ions for specific cell components. The nucleus is a potential site for temporary Cu storage while primary targets for free Cu(II) ions are the thiol groups which reduce the ions to Cu(I). Cu(II) ions show a high affinity for nucleic acids, binding with DNA both at intrastrand and interstrand levels, possibly through intercalation between GC pairs. The ability to chelate Cu(II) ions is seen to be of the order: purine greater than purine ribonucleotides greater than purine ribonucleoside greater than pyrimidine ribonucleotides. Copper is an integral part of enzyme activation and enters into the molecular structure of several proteins, like ceruloplasmin. Cu(II) ion is a potential mutagenic agent as seen by its property of inducing infidelity in DNA synthesis in vitro. Teratogenic activities of copper have been reported but carcinogenicity is not yet confirmed. Copper is an essential component of chromatin and is known to accumulate preferentially in the heterochromatic regions. External application of higher doses, however, induces both clastogenic effects and spindle disturbances. In certain forms, inorganic copper enhances the clastogenic activity of other agents. The most widely studied human genetic maladies linked with copper metabolism are Menkes' and Wilson's diseases. Several mutations are known which influence Cu homeostasis in mammals. Such mutations in mice have been used extensively for biochemical studies.

Animals↗
PubMed1989

Frequency of sister chromatid exchanges induced by trimethyltin chloride in human peripheral blood lymphocytes as related to age of donors. A brief report.

Two concentrations (0.5 microgram and 1.0 microgram) of trimethyltin chloride were added to lymphocytes of healthy male and female donors of different age groups and cultured at 37 degrees C for 72 h. The range and mean number of sister chromatid exchanges were significantly increased in the treated cells but could not be related to age or sex of the donor.

Adolescent↗
PubMed1989

Toxicological consequences of chloroquine and ethanol on the developing fetus.

In the present study, the effects of chloroquine and ethanol administration during gestation have been investigated on the developing rat fetus. Intragastric administration of chloroquine (700 mg/kg body weight) resulted in several structural abnormalities. The incidence of hepatomegaly was increased by 30%, the liquification of visceral organs was increased by 15% and a 9% higher incidence of cleft palate, wrist drop, clubbed foot and brain liquification was observed in the fetuses from the chloroquine-treated group compared to the corresponding controls. Fetuses from the chloroquine-treated group also showed a decrease of about 40% in the body weight and a 30% reduction in the ossification of the sternum. The teratogenic effects of oral ethanol administration in several respects were similar to those of the chloroquine. Ethanol, when administered as 30% of the total daily calories, resulted in growth retardation, resorption, still births, liquification of the brain, wrist drop and clubbed foot. Additionally, ethanol resulted in the inhibition of several metabolic pathways in the liver and brain of the developing fetuses. This included the inhibition of protein, RNA and DNA metabolism in the fetal livers and brains. The feto-toxic effects of these two xenobiotics and their possible molecular mechanisms have been discussed.

Abnormalities, Drug-Induced↗
PubMed1989

A time-course study on effects of aluminium on mitotic cell division in Allium sativum.

Cytotoxic effects of aluminium sulphate on root-tip cells of Allium sativum during a time-course study and during recovery were observed. The endpoints considered were mitotic index and frequencies of aberrant cells and micronuclei induced. Chronic exposure induced mitotic depression and abnormal cells to a degree directly proportional to the concentration used and the period of treatment up to 24 h. A reduction of the early higher level of toxicity was noticed following 48 h of treatment and subsequent recovery in aluminium-free nutrient media in experiments carried out with lower concentrations.

Allium↗
PubMed1989

Betel cytotoxicity.

An attempt to summarise the phytochemical composition of the betel quid, formation of N-nitrosation products during chewing, results of carcinogenicity and mutagenicity studies and the relationship between betel chewing and submucous fibrosis have been made from presently available literature. The present review provides a better understanding of the capacity of the quid ingredients in inducing preneoplastic changes for evaluation of the risk involved with its chewing.

Animals↗
PubMed1989

Increased compliance in response to salbutamol in premature infants with developing bronchopulmonary dysplasia.

We compared the effect of salbutamol and placebo in a double-blind study of preterm infants with bronchopulmonary dysplasia, using a randomized, crossover design with several replicates per subject. Sixty-two tests were performed on 20 ventilator-dependent infants weighing less than 1500 gm. Patients were entered as early as the first week of life and studied for at least 4 weeks or until extubation. Each subject was his own control subject and was randomly assigned to a placebo-salbutamol or salbutamol-placebo sequence administered on 2 consecutive days of each week. Static compliance, expiratory resistance of the respiratory system, and changes in transcutaneous oxygen and carbon dioxide tension were measured. Static compliance improved by 0.240 ml/cm H2O/kg (35.3%) after salbutamol and by 0.010 ml/cm H2O/kg (2.8%) after placebo (p less than 0.0001). The presence of a predetermined decrease in carbon dioxide tension correlated with large changes in static compliance per kilogram and with the need for a high level of fractional inspired oxygen. The magnitude of the clinical and physiologic improvement observed, and the early response suggest that long-term bronchodilator therapy starting as early as the second week of life may be beneficial for very low birth weight infants with early bronchopulmonary dysplasia.

Albuterol↗
PubMed1989

Serum enzymes in head and neck cancer. IV: 5-nucleotidase.

Serum 5-nucleotidase levels have been estimated in a group of 50 patients with head and neck cancer. The mean value was significantly higher in patients compared to the controls. In patients with non-malignant growths, the activity was comparable with the controls. The increase was higher in patients with proliferative lesions than those with ulcerative growths. Enzyme activity was found to be increased with the advancement in the stage of cancer. The rise was comparatively higher in patients with cervical metastasis. After radiotherapy, a gradual and significant reduction of serum 5-nucleotidase activity was observed.

5'-Nucleotidase↗