Search PubMed⌕ Search

Biomedical subjects

A Sharma

Publications and source records attributed to A Sharma.

At least 739 records · Page 41Linked to original sources
PubMed1991

Cytogenetic damage induced in vivo to mice by single exposure to cesium chloride.

Female laboratory bred albino mice (2n = 40) were orally administered cesium chloride (CsCl) in aqueous solution as a single dose and the damage induced at the chromosomal level was observed in bone marrow cells after 6, 12, 18, and 24 hours of exposure. The concentrations of the chemical given were calculated as fractions of the LD50, namely 1/5, 1/10, and 1/20. The cytogenetic endpoints screened for were chromosomal aberrations (CA) and divisional frequency or mitotic index (MI). The frequency of chromosomal aberrations induced was directly proportional to the concentration of the chemical administered. The highest dose was the most toxic and was considered to be the maximum tolerance level. Effects on divisional frequency were variable, the highest concentration being significantly mitostatic, the middle one ineffective, and the lowest slightly mitogenic. In general, the observations indicate that CsCl is clastogenic when administered orally to mice in vivo and the effects are dose-dependent.

Analysis of Variance↗
PubMed1991

Traumatic aneurysm of superficial temporal artery. CT demonstration.

A case of traumatic pseudo-aneurysm of the superficial temporal artery documented on Computed tomography (CT) and angiography is described in a 55-years-old female, who was treated by surgical excision. Computed tomographic appearance of this lesion is illustrated. This represents, to our knowledge, the first CT demonstration of traumatic aneurysm of superficial temporal artery within a large subgaleal haematoma.

Accidents, Occupational↗
PubMed1991

Comparative efficacy of chlorophyllin in reducing cytotoxicity of some heavy metals.

The potential of chlorophyllin in reducing clastogenicity was studied against two concentrations of each of three potent metallic clastogens (cesium chloride, mercuric chloride and cobalt chloride) in bone marrow cells of mice in vivo. The respective salts and chlorophyllin were administered orally to mice by gavaging in different combinations. Simultaneous administration of chlorophyllin with both concentrations of each salt reduced the clastogenic effects in the order Cs greater than Hg greater than Co. Chlorophyllin could not decrease the clastogenic effects when administered 2 h before the salts.

Animals↗
PubMed1991

Cytotoxicity of zinc chloride in mice in vivo.

Intraperitoneal administration of zinc chloride (ZnCl2) to Swiss albino mice in vivo induced a significant (p less than or equal to 0.05) increase in the frequencies of chromosomal aberrations of the bone-marrow cells at all concentrations used following acute (7.5, 10, 15 mg/kg body weight) and chronic (2.0, 3.0 mg/kg body wt) treatment. The degree of clastogenicity was directly proportional to the concentrations (p less than or equal to 0.05, trend test) and indirectly to the period of treatment (p less than or equal to 0.05, ANOVA test). It induced a dose-dependent, statistically significant increase (Mann-Whitney U statistics, Student's t-test) in sperm-head abnormalities. The data designate ZnCl2 as a potent clastogen and as a toxic chemical at the concentrations used.

Animals↗
PubMed1991

Modification of cesium toxicity by calcium in mammalian system.

The interaction between cesium chloride CsCl and calcium chloride CaCl2 was observed in bone marrow chromosomes of mice. The two salts were administered orally to laboratory bred Swiss albino mice in vivo singly or one followed by the other, or both simultaneously. CsCl induced chromosomal aberrations in frequencies directly proportional to the dose administered. The frequency of aberrations was reduced significantly when the two chemicals were administered simultaneously or when CaCl2 was given 2 h before CsCl. Thus, CaCl2 is able to protect against the cytotoxicity of CsCl.

Administration, Oral↗
PubMed1991

Chromosomal aberrations induced by cobaltous chloride in mice in vivo.

The effects of cobaltous chloride in inducing chromosomal aberrations were observed on laboratory bred mice in vivo after single oral administration of different fractions (1/10, 1/20, 1/40) of the lethal toxic dose of the salt. Bone marrow cells were flushed out and processed for chromosome studies following colchicine, hypotonic, giemsa, air drying procedure. The parameters screened were chromosomal aberrations, with and without gaps and break per cell. Slides were screened after the expiry of 6, 12, 18, and 24 h. Statistical analysis indicated the clastogenic effects of the salt. The degree of chromosome damage was directly related to the concentration, and also to the period after administration. The different stages of the cell cycle were affected.

Administration, Oral↗
PubMed1991

Frequency of chromosome aberrations induced by trimethyltin chloride in human peripheral blood lymphocytes in vitro: related to age of donors.

Human peripheral blood lymphocytes of healthy male and female individuals of different age groups were treated with two aqueous doses (0.5 microgram and 1.0 microgram) of trimethyltin chloride in mitogen stimulated and serum supplemented culture medium for 72 h at 37 degrees C. Chromatid and chromosome types of aberrations were observed to be increased in both treated sets in all age groups. Significant variations were observed between age groups (P less than 0.001) and between experimental sets (P less than 0.001). Moreover, interaction of chemical and donors age was statistically highly significant (P less than 0.05-P less than 0.001). However, no linear correlation between the increase of donor's age and aberrations was observed.

Adolescent↗
PubMed1991

Anticlastogenic activity of beta-carotene against cyclophosphamide in mice in vivo.

beta-Carotene (BC), a natural food colourant and an antioxidant, acts as an antimutagen/anticarcinogen in several test systems. The anticlastogenic activity of BC against cyclophosphamide (CP) was studied in bone marrow cells of mice in vivo. Seven days' oral priming with BC (2.7 and 27 mg/kg b.w.) followed by an acute treatment with cyclophosphamide (25 mg/kg b.w.; i.p.) inhibited clastogenicity. The values of chromosomal aberrations and micronucleated polychromatic erythrocytes were consistently lower than the sum of the expected values of BC and CP given individually. This antagonistic response indicates anticlastogenic activity of BC against CP.

Animals↗
PubMed1991

Effect of chlorophyllin on mercuric chloride-induced clastogenicity in mice.

The effect of chlorophyllin (1.5 mg/kg body weight) on the clastogenicity of mercuric chloride (HgCl2) was studied in vivo in mouse bone marrow cells. HgCl2 (3.0, 6.0 and 12.0 mg/kg body weight) administered by gavage induced chromosomal aberrations at frequencies directly proportional to the dose. Chlorophyllin was not clastogenic, and significantly reduced the mitotic index when given alone. Chlorophyllin administered simultaneously with HgCl2 significantly reduced the frequencies of chromosomal aberrations in a dose-dependent manner. When given simultaneously with the lowest HgCl2 concentration tested (3.0 mg/kg body weight), chlorophyllin provided total protection. A lower degree of protection was given by chlorophyllin administered 2 hr before HgCl2. The data demonstrate the potential of green plant components to modify the genotoxic activity of HgCl2 when administered orally.

Administration, Oral↗
PubMed1991

Inhibition of clastogenic effects of cesium chloride in mice in vivo by chlorophyllin.

The antagonistic effect of chlorophyllin was tested in reducing the clastogenic action of cesium chloride (CsCl) in vivo on mice bone marrow cells. CsCl induced chromosomal aberration in frequencies directly proportional to the dose administered. Chlorophyllin, when given alone, was not clastogenic even at a concentration of 1.5 mg/kg body wt. of the animal. Simultaneous administration of chlorophyllin and CsCl reduced chromosomal aberrations significantly at 24 h. Exposure to the same dose of chlorophyllin 2 h before exposure to CsCl also decreased clastogenic effects but to a lesser extent. These findings are of importance in view of the uptake of radioactive Cs by green plants after nuclear fallout.

Animals↗
PubMed1991

Relationship of clastogenic effects of zirconium oxychloride to dose and duration of exposure in bone marrow cells of mice in vivo.

Zirconium oxychloride was administered as a single oral dose to laboratory-bred Swiss albino mice corresponding to 1/2, 1/6 and 1/20 of the LD50 values. Bone marrow cells were screened after 6, 12 and 24h for chromosomal aberrations following an air-drying-Giemsa schedule. The frequencies of chromosomal breaks and alterations induced increased significantly at a rate directly proportional to the concentration used. The increase was also related to the period after exposure, although to a less extent than the concentration used. No direct relationship could be observed to the sex of the animal.

Administration, Oral↗
PubMed1991

Temporal events regulating the early phases of the mammalian cell cycle.

It is proposed that the regulation of the pathways directing mammalian cell cycle progression involves several oncogenes. A summary of what is known about some of these regulatory oncogenes (fos, jun, myc, and Rb-1) and where they might function in the progression of a cell from G0 to G1 and G1 to S is presented. Data on two replication-dependent genes, those encoding histones and thymidine kinase, respectively, are also presented as models for describing transcriptional and post-transcriptional events at the G1-S border.

Animals↗
PubMed1991

Solitary retinal astrocytoma.

A two-year-old female child presented with a left retinal mass in front of the optic disc and total serous retinal detachment. Enucleation was performed for suspected retinoblastoma. Histopathologically the tumour was composed of astrocytic giant cells with a few spindle-shaped astrocytes. Presence of multiple necrotic foci in the tumour resembling micro-abscesses and extension of tumour cells beyond lamina cribrosa were additional unusual features.

Astrocytoma↗
PubMed1991

Medullary carcinoma of the thyroid presenting as multifocal bronchial carcinoid tumour.

A 21 year old man presented with diarrhoea and flushing after meals and later developed miliary shadowing on his chest radiograph. Multifocal bronchial carcinoid tumour was diagnosed initially, but at necropsy metastatic medullary carcinoma of the thyroid was found. Multifocal bronchial carcinoid tumour should not be accepted as a primary diagnosis without first excluding medullary carcinoma of the thyroid because of the need to screen relatives of affected patients.

Adult↗
PubMed1991

Synthesis and release of cell surface-derived and sulfated lactosaminoglycans by human ovarian carcinoma cells.

Ovarian carcinoma cell clusters were isolated from patient effusions. Cell-surface glycoconjugates were radiolabelled by a galactose oxidase-borotritide method. The surface-labelled glycoconjugates and metabolically labelled glycoconjugates released to culture medium were characterized. The surface-derived glycoconjugates were highly heterodisperse and had the same molecular weight distribution as the metabolically labelled components. Lectin precipitation assays showed that both classes of glycoconjugates contained N-linked oligosaccharides bearing N-acetyllactosamine moieties. A121 ovarian carcinoma cells also synthesized and released a heterodisperse array of glycoconjugates to culture medium. Ricinus communis agglutinin I (RCAI) precipitated glycoconjugates of MW greater than 100 kDa for both A121 cells and cells from effusions. Cells of different ovarian carcinoma histology yielded similar results. Metabolic labelling experiments with 35SO4 showed that the RACI-bound glycoconjugates released by A121 cells were sulfated. The RCAI-bound sulfated lactosaminoglycans may be associated with malignant transformation and/or metastasis since similar components were not produced by mesothelial cells isolated from effusions [Allen, H.J., M. Gamarra M.S. Piver and E.A.Z. Johnson (1989). Cancer Biochem. Biophys. 10, 219-226].

Amino Sugars↗
PubMed1991

Prevalence & spectrum of congenital malformations in a prospective study at a teaching hospital.

A prospective survey for congenital malformations at birth, at a teaching hospital, over a period of two and half years on 9405 consecutive single births has shown that prevalence of major congenital malformations in live births was 1.6 per cent and in still births 16.4 per cent. There was no significant difference in the prevalence of congenital malformations between Hindus (2.0%) and Muslims (2.7%) but amongst Muslims with consanguinity the prevalence of congenital malformation was 4.6 per cent compared to 2.3 per cent in non-consanguineous Muslim spouses (P less than 0.05). Open neural tube defect was the single most common anomaly (31.7% of all malformations) occurring at a rate of 4.7 per 1000 single births, with equal prevalence of anencephaly and meningomyelocoele. Case control study showed that history of concomitant medical illness, drug intake during the first trimester, threatened abortion, hydramnios and pre-eclamptic toxaemia in the current pregnancy were significantly associated with the occurrence of congenital malformations.

Congenital Abnormalities↗