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Biomedical subjects

A Sharma

Publications and source records attributed to A Sharma.

At least 775 records · Page 43Linked to original sources
PubMed1990

Modification of clastogenicity of lead and aluminium in mouse bone marrow cells by dietary ingestion of Phyllanthus emblica fruit extract.

Extract of Phyllanthus emblica fruit and ascorbic acid were evaluated separately for protection against clastogenicity induced by lead (Pb) and aluminium (Al) salts on mouse bone marrow chromosomes. Oral administration of Phyllanthus fruit extract (PFE) for 7 days before exposure to both metals by intraperitoneal injection increased the frequency of cell division and reduced the frequency of chromosome breaks significantly. Comparable doses of synthetic ascorbic acid (AA) were less effective and could protect against the effects of Al and only a low dose of Pb (10 mg/kg body weight). AA administered before treatment in mice given higher doses of Pb (40 mg/kg body weight) enhanced the frequency of chromosome breaks, giving a synergistic effect. The higher protection afforded by PFE may be due to the combined action of all ingredients, rather than to AA alone.

Administration, Oral↗
PubMed1990

Comparison of different plants in screening for Mn clastogenicity.

Cationic (MnSO4.H2O) and anionic (KMnO4) manganese salts in aqueous solutions enhanced the frequency of chromosomal aberrations including both chromosome- and chromatid-type breaks, gaps, translocations and spindle disturbances in different plant systems in vivo to a statistically significant level. The activity of the cationic salt was more drastic, particularly on the submerged plant studied (Vallisneria spiralis L.), on prolonged exposure, when compared with bulbs of Allium cepa L. and seeds of Pisum sativum L.

Chromosome Aberrations↗
PubMed1990

Comparison of clastogenicity of inorganic Mn administered in cationic and anionic forms in vivo.

A comparison of the cytotoxic activity of cationic (MnSO4) and anionic (KMnO4) salts of inorganic manganese in the mouse in vivo indicated that the former was more strongly clastogenic than the latter. Mice were administered different doses of the salt orally over a period of 3 weeks. In general, both the frequencies of chromosomal aberrations in bone marrow cells and micronuclei were increased significantly by both salts. Sperm-head abnormalities showed a significant enhancement as well. The clastogenic effects were directly related to the concentrations used and were not markedly influenced by the duration of treatment. In view of the known affinity of Mn2+ for chromosomal components, it has been suggested that the effects were mediated by these ions produced directly from MnSO4 and indirectly from KMnO4 following conversion under acidic pH of the gastric juices.

Animals↗
PubMed1990

Frequency of micronuclei induced in peripheral lymphocytes by trimethyltin chloride.

The clastogenicity of trimethyltin chloride was evaluated in human peripheral blood lymphocytes with micronucleus counts (MNC) as the endpoint. Two concentrations (0.5 micrograms and 1.0 microgram) of trimethyltin chloride were added to lymphocytes of healthy male and female subjects of different age groups, in mitogen-stimulated and serum-supplemented culture medium (RPMI 1640, Gibco) for 48 h at 37 degrees C. A significant increase in micronucleus counts was observed with both doses, which was more pronounced with the lower dose. ANOVA in male and female donors revealed significant differences between age groups (P less than 0.001), chemical concentrations (P less than 0.001) and for the interaction of these 2 factors (P less than 0.05 in females only). However, no regular increase or decrease in MNC frequencies was observed with the donor's age. Higher frequencies of MNC enhancement were observed in male individuals than in females.

Adolescent↗
PubMed1990

Clastogenic effects of cesium chloride on mouse bone marrow cells in vivo.

Clastogenic effects of cesium chloride (CsCl) on mouse bone marrow cells in vivo following oral administration were studied after 24 h. The incidence of chromosome aberrations increased linearly with increasing concentrations of the chemical from 1/20th to 1/5th of the LD50. The frequency of cell division was also enhanced by the lower doses but higher doses were mitostatic. This report is the first on the clastogenicity of cesium on animals.

Administration, Oral↗
PubMed1990

Clastogenic effects of copper sulphate on the bone marrow chromosomes of mice in vivo.

Copper sulphate administered intraperitoneally to Swiss albino mice in vivo induced a significant increase in the frequency of chromosomal aberrations in bone marrow cells as all concentrations used (1.1-6.6 mg/kg b.w.), when compared to the negative control. Statistical analysis indicates that the degree of clastogenicity was directly related to the concentrations used and indirectly to the period of exposure. The effect was maximal at 6 h after treatment as compared with 12 and 24 h.

Animals↗
PubMed1990

Cytotoxic effects of zirconium oxychloride on bone marrow cells of mice.

A single oral administration of an aqueous solution of zirconium oxychloride to mice of both sexes in concentrations 1/20, 1/6, 1/2 of LD50 induced chromosomal abnormalities in bone marrow cells. The frequencies of aberration were directly proportionate to the concentrations used. Female mice were found to be more susceptible than male mice, though not to a significantly higher level. This is the first report on the clastogenicity of this metal.

Animals↗
PubMed1990

Role of magnetic resonance (MR) in the diagnosis and management of intracranial tuberculomas.

Thirty-one patients with intracranial tuberculomas were diagnosed on the basis of magnetic resonance (MR) imaging. The diagnosis was confirmed in 30; one case was a false-positive. A total of 44 tuberculomas was found in these patients of which 41 were distributed in the cerebral hemispheres, two in the brainstem and one in the cerebellum. No correlation was found between the type of lesion seen on CT and those seen on MR imaging. CT was negative in one patient with a low brainstem tuberculoma. The final diagnosis was based on the response to antituberculous drug treatment as judged by serial MR imaging in 29 patients and by biopsy in one; and one was false-positive. Thirty-nine tuberculomas, all under 2.5 cm in size, showed complete resolution after 5-8 months of treatment. The remaining five lesions were larger than 2.5 cm; four showed a 50% reduction in size after 12 months of treatment and one was completely excised. Three types of response are described to the treatment with anti-tuberculous drugs. The diagnosis of intracranial tuberculomas can be made more objectively with MR imaging.

Adolescent↗
PubMed1990

Serum and tear immunoglobulins in bacterial, fungal and viral corneal ulcers.

Serum and tear IgA, IgG and IgM levels were studied in patients with bacterial, fungal and viral corneal ulcers. In patients with viral corneal ulcers serum IgA and IgG levels were found to be significantly raised, while IgM concentration remained unaltered. In bacterial and mycotic ulcerations, serum IgA, IgG and IgM levels remained unaltered. All three immunoglobulins were found to be raised in tears of patients with viral corneal ulcers, while only IgA levels were found to be increased in bacterial and mycotic ulcerations.

Adult↗
PubMed1990

Multiple scleral abscesses with recurrent bacterial endophthalmitis eight months following cataract surgery.

Scleral involvement in association with endophthalmitis is unusual. We report a case of recurrent bacterial endophthalmitis and multiple scleral abscesses occurring 8 months following cataract extraction. Culture of pus from scleral abscesses first grew Pseudomonas aeruginosa; and klebsiella pneumoniae on recurrence. The patient responded to intensive topical and systemic antibiotic therapy and recovered visual acuity of 20/60.

Abscess↗
PubMed1990

Retinol inhibition of in vitro human neutrophil superoxide anion release.

Retinol deficiency has been clinically associated with visual impairment as well as altered growth and differentiation of various epithelial cell populations. An additional factor that may be operative in the setting of retinol deficiency is impaired immunomodulation of the neutrophil inflammatory response. Our study demonstrated a concentration-dependent inhibition by retinol of activated neutrophil superoxide anion (O2.-) release. Concentration of drug (retinol) causing 50% inhibition of initial velocity O2.- production (IC50) was 42.6 +/- 10.9 microM. Latter phases of the O2.- release reaction displayed significantly lower IC50 values. Similarly, as time of retinol-neutrophil incubation was increased, IC50 decreased. Retinol inhibition of neutrophil O2.- did not appear to involve activation/desensitization, cytotoxicity, or free-radical scavenging mechanisms. Retinol was shown to inhibit intact PMN O2.- release even after addition of the respiratory burst stimulus. Moreover, retinol inhibited O2.- release in membranes isolated from activated neutrophils. In addition to promoting proper organization and differentiation of epithelial cells, appropriate plasma/tissue retinol levels may also modulate the neutrophil tissue inflammatory response.

Adult↗
PubMed1990

Cytogenetic studies in human populations exposed to gas leak at Bhopal, India.

Frequencies of chromosomal abnormalities, sister chromatid exchanges, and replicative index were assessed following peripheral lymphocyte culture in 129 individuals from Bhopal, India. Of these, 83 persons (40 male and 43 female) had been exposed directly to the methyl isocyanate (MIC) gas after the accident at the Union Carbide plant on December 2 and 3, 1984. The remaining 46 samples were taken from age-matched unexposed persons in the same city. Chromosome aberrations were recorded at first cycle metaphase (M1) and sister chromatid exchanges, at second cycle metaphase (M2), following standard schedule. The frequency of chromosomal aberrations was, in general, higher in individuals from the exposed populations, with the females showing a higher incidence. Nondisjunction of chromosomes or laggard was rare. The frequencies of sister chromatid exchanges and depression in mitotic and replicative indices could not be related to exposure or sex. The persistence of chromosomal abnormalities in the form of replicating minutes and exchange configurations, even 1114 days after exposure to the gas, may indicate a residual effect on T-cell precursors.

Accidents, Occupational↗
PubMed1990

Effect of testosterone on the glycosphingolipid composition of the rat kidney.

A series of experiments was conducted to examine the effect of subcutaneous administration of synthetic testosterone (500 micrograms/100 g body weight) on the acidic and neutral glycolipids. The kidney glycosphingolipids were separated by using Sep-Pak cartridge column. Florisil column, and high performance thin layer chromatography, and analyzed by gas liquid chromatography. Testosterone administration increased the total content of ceramide, acidic and neutral glycolipids. The increase in total neutral glycolipids was mainly due to an increase in glucosyl- and globotetraosylceramide. The increase in total gangliosides was due to the increase in GM3 (hematoside) and "others". The relative percentage of N-glycolylneuraminic acid in GM3 was increased whereas the relative percentage of sphingoside and phytosphingosine were increased and decreased, respectively, in GM3, glucosyl- and globotetraosylceramide. The relative percentage and chain length of hydroxy and nonhydroxy fatty acids of major glycosphingolipids were altered in this organ.

Animals↗
PubMed1990

A comparison of the effects of conventional insulin treatment and continuous insulin infusion therapy on established morphological and biochemical abnormalities of peripheral nerve in experimental diabetes.

This study compared the relative efficacy of conventional insulin therapy (CIT) and continuous subcutaneous insulin infusion therapy (CSII) in correcting a range of morphological and biochemical abnormalities of peripheral nerve in rodents with experimental diabetes mellitus. Both treatments were applied for two months and were commenced two months after the induction of diabetes in 11 week old rats. Better diurnal glycaemic control was achieved with CSII therapy than with CIT. An established deficit in body weight in the diabetic animals was partially, but not fully corrected by both treatments. Retardation of long bone growth in the diabetic animals was corrected by CSII therapy but not CIT. Elevated levels of sciatic nerve glucose, sorbitol and fructose found in diabetic animals were normalized by both treatments. However, depleted levels of nerve myo-inositol which were also found in diabetic animals were restored to normal only by CSII therapy. Abnormal myelinated nerve fibre morphology, indexed by fibre and axon cross-sectional area measurements, was again corrected more effectively by CSII therapy. This study has demonstrated that often partial and sometimes complete amelioration of established biochemical and morphological abnormalities of peripheral nerve in diabetic animals can be achieved by the application of either CSII therapy or CIT. However, under the controlled conditions of this experimental study better overall performance was gained from CSII therapy.

Animals↗
PubMed1990

A new perspective on myelinated nerve fibre pathology in experimental diabetes.

Quantitative electron-microscopical techniques were used to investigate the effects of experimental streptozotocin-diabetes on the longitudinal morphology of myelinated fibres in rat sural nerve. The morphology of myelinated fibres was symmetrical at proximal and distal levels in the nerves of control animals aged three months. Further development of myelinated fibres in control animals between three and seven months of age involved proximal and distal fibre growth with the simultaneous formation of a proximo-distal taper. The same pattern of fibre growth was not observed in animals with experimental diabetes. Although both fibre and axon size increased with age in both proximal and distal regions of sural nerve in the diabetic animals, a taper was not established. This impairment of fibre maturation by experimental diabetes was manifest more strongly in the proximal part of the nerve. There was no evidence favouring selective involvement of the axon or Schwann cell in the fibre pathology found in the diabetic animals. The results of this study do not support previous suggestions that experimental diabetic neuropathy is mainly a dying-back axonopathy. This report reaffirms that normal maturation of myelinated fibres is prevented by experimental diabetes mellitus.

Analysis of Variance↗
PubMed1990

Sister chromatid exchange and chromosome aberrations induced by curcumin and tartrazine on mammalian cells in vivo.

Sister chromatid exchanges (SCEs) and chromosomal aberrations induced by curcumin (a natural dye) and tartrazine (a synthetic dye) were studied on bone marrow cells of mice and rats following acute and chronic exposure via the diet. Except for two low concentrations in the curcumin and one low concentration in the tartrazine treated series a significant increase in SCEs was observed in all the concentrations of the two dyes tested. Except for two high concentrations during the 9 months treatment no significant increase in chromosomal aberrations was observed in the curcumin treated series, whereas tartrazine showed a significant increase in chromosomal aberrations in some of the higher concentrations in all the series tested. The results indicate that tartrazine is more clastogenic than curcumin.

Animals↗
PubMed1990

Hepatoprotective activity of andrographolide from Andrographis paniculata against carbontetrachloride.

Andrographolide, a diterpenoid lactone, was isolated (yield 0.78% w/w) from A. paniculata (whole plant). Its LD50 in male mice was 11.46 g/kg, ip. Antihepatotoxic activity of andrographolide (100 mg/kg, ip) was compared with 861.33 mg/kg, ip, of the methanolic extract (equivalent to 100 mg/kg of andrographolide) and 761.33 mg/kg ip, of the andrographolide-free methanolic extract (equivalent to 861.33 mg/kg of the methanolic extract) of the plant, using CCl4-intoxicated rats. Biochemical parameters like serum transaminases--GOT and GPT, serum alkaline phosphatase, serum bilirubin and hepatic triglycerides were estimated to assess the liver function. Overall inhibition of CCl4-induced increase in the five biochemical parameters was found to be 48.6 per cent (andrographolide), 32.0 per cent (methanolic extract) and 15.0 per cent (andrographolide-free methanolic extract). These biochemical observations were supplemented by histopathological examination of the liver slices. Further, andrographolide (100 mg/kg, ip) was found to normalize completely the CCl4-induced increase in the pentobarbitone induced sleep time of mice. The results suggest that andrographolide is the major active antihepatotoxic principle present in A. paniculata.

Analysis of Variance↗