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Biomedical subjects

A Sharma

Publications and source records attributed to A Sharma.

At least 811 records · Page 45Linked to original sources
PubMed1989

Interaction of cellular factors related to the Jun oncoprotein with the promoter of a replication-dependent hamster histone H3.2 gene.

The promoter region of a replication-dependent histone H3.2 gene contains a putative DNA binding site for the Jun oncoprotein within a 32-nucleotide regulatory domain. The hamster sequence differs by one nucleotide from the AP-1 consensus sequence found in several promoters responsive to phorbol 12-myristate 13-acetate. We have identified the factors interacting with this region as 42- and 45-kDa proteins by DNA affinity chromatography, immunoblotting, and UV crosslinking. These proteins, which are candidates for conferring high-level expression to the histone promoter, share an antigenic epitope with the DNA-binding domain of Jun but diverge from it at the amino terminus. The interaction of these proteins with the promoter of a replication-dependent cellular gene provides evidence that members of the Jun oncoprotein family may play specific roles in the expression of genes essential for progression of the cell cycle.

Animals↗
PubMed1989

Autonomously functioning thyroid nodule.

We report 408 cases of autonomously functioning thyroid nodule (AFTN); 85.5% occurred in female patients, for a male-female ratio of 1:6. Eighty-nine patients (21.8%) were hyperthyroid, 76 of them being female, also yielding a male-female ratio of 1:6. There was a linear increase in the incidence of hyperthyroidism with age and with an increase in the size of the nodule, especially for nodules more than 3 cm in diameter. There was a significantly higher incidence of hyperthyroidism for nodules of the same size when they occurred in patients more than 40 years of age. There was a corresponding increase in hyperthyroidism with an increase in the length of time after the initial detection of the nodule; this finding was significantly greater in patients more than 40 years of age. Thus, the age of the patient was found to be a more important determinant in the production of hyperthyroidism associated with an AFTN than either the size of the nodule or the duration of symptoms.

Adult↗
PubMed1989

Cell cycle regulation of H2b histone octamer DNA-binding activity in Chinese hamster lung fibroblasts.

The promoter regions of H2b histone genes contain a 14-base-pair element which includes the octamer ATTTGCAT. Mutational analysis has implicated the octamer element in the cell cycle-dependent expression of H2b histone genes. In this report, we address the question of whether the DNA-binding activity of the octamer transcription factor is itself cell cycle regulated. By using a gel mobility shift assay, we measured the relative amounts of octamer-binding activity during various phases of the cell cycle in serum-synchronized Chinese hamster fibroblasts. We found that the activity increased approximately fivefold between late G1 phase and early S phase and then decreased threefold between late S phase and G2 phase. These cell cycle-dependent changes in octamer DNA-binding activity may in part account for the selective transcription of H2b histone genes in late G1 and S phases.

Animals↗
PubMed1989

Notting Hill Carnival 1988.

The injuries sustained at the 1988 Notting Hill Carnival were documented in order to suggest ways in which these might be reduced in future years. Sixty-four patients presented to six hospitals participating in the study over a 48-h period, most of whom were victims of accidents (63%) rather than assaults (37%). Many of the accidents were caused by motorized floats or by stepping on broken glass.

Emergency Medical Services↗
PubMed1989

Does the warming of local anaesthetic reduce the pain of its injection?

One hundred and fifty-seven patients who warranted the injection of local anaesthetic were divided into two groups. One group received local anaesthetic at room temperature (21 degrees C) and the other at body temperature (37 degrees C). The pain resulting from the injection was assessed using a visual analogue scale. There was no significant difference in the level of pain experienced by the two patient groups. It is concluded that no advantage is gained by the warming of local anaesthetic before its administration.

Adolescent↗
PubMed1989

Chromosomal alterations and DNA content in rats during ageing.

Chromosome analysis of bone marrow cells from 96 sex-matched Rattus norvegicus of 12 different age groups showed a significant increase in hypodiploid cells with ageing. However, in meiotic preparations from gonadal cells of male rats the frequency of hypodiploid or hyperdiploid cells did not change significantly. In situ DNA estimation of bone marrow nuclei, following Feulgen cytophotometry, also did not show any significant difference with gradual age changes.

Aging↗
PubMed1989

The glycosphingolipid composition and glycosyltransferase activities of the small intestinal mucosa of testosterone-treated rats.

Prior studies have demonstrated that sex hormones can influence the glycosphingolipid composition of different organs, including small intestine. However, to date, the effects of testosterone on glycosphingolipids of rat small intestinal mucosa have not been examined. Experiments were conducted to examine the effect of subcutaneous administration of synthetic testosterone (500 micrograms/100 g body wt.) on the gangliosides and neutral glycosphingolipids of rat small intestinal mucosa. Their results demonstrated that testosterone administrations: (i) increased the ganglioside content including hematoside (GM3); (ii) increased the total content of neutral glycosphingolipids, which was due to the increases in glucosylceramide and globotriaosylceramide; (iii) increased the activities of cytidine 5'-monophosphate-N-acetylneuraminic acid: lactosylceramide sialyltransferase, and UDPgalactose: lactosylceramide galactosyltransferase; (iv) increased the percentage of the long chain base phytosphingosine in hematoside, glucosyl-, and globotriaosylceramide; and (v) significantly altered the fatty acid composition of each of these glycosphingolipids. These results demonstrate that administration of testosterone induces alterations in glycosphingolipid composition and glycosyltransferases activities in rat small intestinal mucosa.

Animals↗
PubMed1989

Cytotoxic effects of trimethyltin chloride on human peripheral blood lymphocytes in vitro.

Trimethyltin chloride was found to induce cytotoxic damage in vitro in human peripheral blood lymphocytes. Two concentrations (0.5 micrograms and 1.0 micrograms) were added to lymphocytes from male and female subjects in mitogen stimulated and serum supplemented culture medium for 72 h. A dose-related increase of inhibition of replication index (P less than 0.01) and cell division (P less than 0.001) was observed. The frequencies of abnormal cells and chromosomal aberrations such as chromatid and chromosome breaks, dicentrics, triradial and quadriradial configurations were increased significantly (P less than 0.001), as were micronucleus counts (P less than 0.001) and sister chromatid exchanges (P less than 0.001). Endoreduplication, an extremely rare spontaneous event in human lymphocytes, was observed in a few cases at all dose levels. The effects were more pronounced in lymphocytes obtained from habitual smokers.

Cell Cycle↗
PubMed1989

Basic fibroblast growth factor does not initiate mitogenic signalling via phosphoinositide hydrolysis in PC12 cells.

Basic fibroblast growth factor (b FGF) was found to be equally potent mitogen as compared to alpha-thrombin to reinitiate DNA synthesis in quiescent PC12 cells. Whereas thrombin was found to be an activator of phospholipase C as judged by a rapid increase in the formation of inositol triphosphate, inositol biphosphate and a massive accumulation of inositol phosphate when 20 mM LiCl was present as an inhibitor of inositol mono phosphatases, basic FGF failed to induce the breakdown of the polyphosphoinositides in quiescent PC12 cells to any appreciable levels, however, a simultaneous increase in the level of diacylglycerol was observed. b FGF also failed to stimulate protein kinase C which is believed to be activated by diacylglycerol. It is therefore concluded that bFGF receptor mediated 'signalling is not via phospholipase C activation and bFGF's early mitogenic responses and DNA synthesis are initiated independent of the inositol lipids and protein kinase C activation. Thus bFGF must have its own unique signal transducing mechanism independent of inositol pathways.

Animals↗
PubMed1989

DNA ploidy with relation to histology in tumours of breast and rectum.

Biopsy materials from breast and rectal tumour cases were studied for cytophotometric analysis of DNA ploidy levels. Aneuploid DNA patterns were observed in majority cases of late stage and poorly differentiated carcinomas. Increased aneuploidy was also observed in metastatic growths and post menopausal cases of breast cancers.

Aneuploidy↗
PubMed1989

Virulence of Giardia lamblia: an in vitro study on host-parasite interaction.

Trophozoites of G. lamblia, a human parasite, were lysed by polymorphonuclear leukocytes (PMNL) of healthy individuals during in vitro interaction. However, the parasite damaged PMNL of giardiasis patients. A prior treatment of giardia trophozoites with anti-giardia serum, caused agglutination of pathogen and, thereby, the cytotoxic capacity of the parasite was reduced. Interaction of giardia-trophozoites with peritoneal macrophage, derived from infected mouse, reduced the phagocytic activity of the latter to 43% (against 100% in control). Macrophage activity was, however, stimulated to 131% when the mice were immunized with giardia antigen prior to experimental infection. Giardia extract proved cytotoxic at a dose of 0.7 mg, to HeLa cells in tissue culture. These in vitro studies offer experimental evidence of the cytotoxic and immuno-toxic behaviour of G. lamblia towards the host cells.

Animals↗
PubMed1989

Adrenocortical involvement in aluminium phosphide poisoning.

The effect of aluminium phosphide (AlP) which is a systemic poison on the adrenal cortex was studied in 30 patients of AlP poisoning. A significant rise in the plasma cortisol level (greater than 1048 nmol/l) was observed in the twenty patients. Mortality was 50 per cent. Autopsy study could be undertaken only in 10 patients. Histopathology showed mild to moderate changes. In the rest (10 patients), the adrenal cortex was critically involved and the cortisol level failed to rise beyond normal levels (less than 690 nmol/l). The histopathology revealed severe changes (complete lipid depletion, haemorrhage, necrosis etc.) and all these patients died. In the critically ill patients, the cortisol levels remained low because of severe adreno-cortical involvement. The changes in the adrenal cortex could be due to shock or to cellular toxic effect of phosphine. The histopathological changes in various viscera showed congestion, edema and cellular infiltration. In the heart, there were patchy areas of necrosis, while the liver showed fatty changes and the lungs showed, in addition areas of gray/red hepatization. There was no adrenal apoplexy or extensive haemorrhage that could explain shock in these patients. Cardiogenic shock could not be confirmed due to lack of facilities for haemodynamic monitoring, but there was histopathological evidence in support of cardiovascular shock.

Adolescent↗
PubMed1989

Plasma cortisol levels in enteric fever.

Plasma cortisol levels were estimated in twenty two culture positive cases of enteric fever and in equal number of patients with fever due to non-enteric causes. Patients of typhoid with severe toxaemia and or some complication were found to have lowered mean levels on the day of admission and at the time of defervescence. The levels returned to normal one week later. Patients of typhoid with mild to moderate illness showed elevated levels of plasma cortisol. To conclude cases of typhoid with severe toxaemia and/or complications have lower cortisol levels and may be given supplementary steroids (if no contraindications exist). Since these values return to normal one week after fever subsides, supplementary steroids need not be given for longer than one week of acute illness.

Adolescent↗
PubMed1989

Kinetics of corneal epithelial maintenance and graft loss. A population balance model.

We use a population balance model to study the mechanism and the rate of centripetal migration of epithelial cells, renewal of the corneal epithelial population by the cell derived from (progeny of) the limbal stem cells and the kinetics of the replacement of the donor corneal epithelium. The epithelial mass is constant under the normal circumstances and therefore the rate of cellular entry due to centripetal motion and mitosis into any epithelial volume must equal the cell loss from the same volume. The magnitude of the centripetal velocity and the rate of replacement of the donor tissue following keratoplasty are shown to depend only on the following directly quantifiable factors--the difference in the mitotic rates of the corneal and limbal epithelia and the radii of these two epithelia. The a priori model predictions are found to be in very good agreement with the observed centripetal velocities and the rate of corneal graft replacement. The model provides an independent support for the hypothesis that the stem cells for the corneal epithelium are located in the limbus and are responsible for a slow replenishment of the corneal epithelial cell. The model suggests some factors that diminish the centripetal supply of cells and thus provides insights into the pathogenesis of persistent corneal defects and delayed reepithelialization of defects and grafts. The model is suitable for interpreting and quantitatively correlating the influence of some epithelial alterations and drugs on the centripetal supply of epithelial cells.

Animals↗
PubMed1989

Relationship between multiple drug-resistance & enterotoxin production by Shigella species.

Culture filtrates prepared with strains of Shigella dysenteriae 1 and those of Sh. flexneri and Sh. sonnei, collected from different geographical locations in India caused accumulation of fluid in rabbit gut loops, indicating their capability to produce Shiga and Shiga-like toxins respectively. Sh. boydii strains were noted for the first time to produce Shiga-like toxins. The failure of production of fluid accumulation in rabbit gut by Shigella strains that lacked the R-markers of the antibiotics tested and the gradual enhancement in the secretory response by strains containing R-markers in the increasing order indicate a possible correlation between acquisition of higher number of R-markers and enterotoxic activity. The non-transferable and non-curable nature of most of the drug resistance markers, coupled with the failure of the two transconjugants to elicit a secretory response and the capacity of the single cured variant to retain this property suggest the involvement of certain chromosomal locii in mediating drug resistance and enterotoxicity in Shigella.

Animals↗
PubMed1989

Serum protein patterns in adenocarcinoma of breast and rectum.

Serum protein patterns were studied in 27 cases of adenocarcinoma of breast and rectum by polyacrylamide gel disc electrophoresis. Pretreatment and post-treatment cases showed different protein patterns. The increased number of bands in zone A in pretreatment rectal cancer cases decreased after chemotherapy. Thus, the number and position of bands before and after treatment and in different types of cancer may be used in diagnosis and prognosis of the disease.

Adenocarcinoma↗