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Biomedical subjects

M Sharma

Publications and source records attributed to M Sharma.

At least 109 records · Page 6Linked to original sources
PubMed1994

Effects of carbon dioxide-induced anesthesia on cholinergic parameters in rat brain.

We report that acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities in rat brain were virtually identical whether the rat was anesthetized with carbon dioxide (CO2) before decapitation or decapitated without prior sedation. The AChE and ChAT activities were measured in three brain regions: the hippocampus, cerebral cortex, and cerebellum. Enzyme activities varied significantly by brain region, with the highest values in the hippocampus and the lowest values in the cerebellum. Enzyme activities, however, did not vary with the method of euthanasia, either CO2-induced anesthesia prior to decapitation or decapitation without anesthesia. These data suggest that CO2-induced anesthesia prior to decapitation does not alter activities of these cholinergic markers in rat hippocampus, cerebral cortex, and cerebellum. This method of euthanasia eliminates the need to capture a conscious animal, which reduces stress to the animal and the experimenter.

Acetylcholinesterase↗
PubMed1994

Differential effects on spatial navigation of immunotoxin-induced cholinergic lesions of the medial septal area and nucleus basalis magnocellularis.

The effects on anatomy and behavior of a ribosomal inactivating protein (saporin) coupled to a monoclonal antibody against the low-affinity NGF receptor (NGFr) were examined. In adult rats, NGFr is expressed predominantly in cholinergic neurons of the medial septal area (MSA), diagonal band nuclei, and nucleus basalis magnocellularis (nBM), but also in noncholinergic cerebellar Purkinje cells. Rats with immunotoxin injections to the MSA, nBM, and lateral ventricle were compared to controls on a spatial and cued reference memory task in the Morris maze. Toxin injections to the MSA slightly impaired the initial, but not asymptotic, phase of spatial navigation. Injections to the nBM impaired all phases of spatial navigation. Cued navigation, however, was not affected in either the MSA or nBM group. The ventricular injections severely affected spatial and cued navigation. Acetylcholinesterase (AChE) histochemistry and NGFr and choline acetyltransferase immunohistochemistry revealed a loss of (1) almost all NGFr-positive cholinergic neurons in the MSA and AChE fibers in hippocampus (MSA group); (2) almost all NGFr neurons in the nBM, some in the MSA, most AChE fibers in neocortex and some in the hippocampus (nBM group), and (3) almost all NGFr neurons in the MSA and nBM and their corresponding hippocampal and cortical AChE fibers (ventricular group). Cholinergic nBM projections to the amygdala were largely preserved in all groups. The amount of cholinergic fiber loss in the cortex correlated modestly, but significantly, with the severity of impairment of the asymptotic phase of performance of the spatial task. An unambiguous interpretation of the anatomical locus of behavioral deficits was not possible because of damage to cholinergic striatal interneurons (nBM group) and to noncholinergic cerebellar Purkinje cells (ventricular group). These data suggest that the cholinergic cortical system is critical to the performance of this spatial memory task. Cholinergic denervation of the hippocampus alone, however, is not sufficient to impair markedly performance of this task.

Animals↗
PubMed1994

Protective effect of Rubia cordifolia on lipid peroxide formation in isolated rat liver homogenate.

Rubia cordifolia Linn. (Rubiaceae) is an important component of the ayurvedic system of medicine. It has a variety of uses such as blood purifier, immunomodulant, antiinflammatory and anti-PAF. In this report the anti-peroxidative property of the solvent free alcoholic extract of R. cordifolia has been studied in rat liver homogenate. It prevents the cumene hydroperoxide induced malondialdehyde formation in the dose and time dependent manner. This effect is accompanied by the maintained reduced glutathione level even in the presence of above toxin.

Animals↗
PubMed1994

Carriage of Gardnerella vaginalis in the urethra of Indian men.

A total of 310 consecutive sexually active men attending sexually transmitted disease clinic of the Nehru Hospital, Chandigarh, were studied to assess the prevalence of G vaginalis. Non-gonococcal urethritis (NGU) was diagnosed in 53, acute gonococcal urethritis (AGU) in 20, psychosomatic disorders in 50 and genital ulcer disease in 187 patients. G. vaginalis was isolated in 11 patients (3.5%) only. Of these 11 isolates, 4(7.5%) were from patients with NGU, 2(10.0%) from men diagnosed to have AGU, 3(6%) from the patients with psychosomatic disorders and 2 isolates (1.7%) from patients with genital ulcer disease.

Bacterial Infections↗
PubMed1993

Effect of chronic cadmium exposure on glutathione S-transferase and glutathione peroxidase activities in rhesus monkey: the role of selenium.

The effect of cadmium (Cd) on the activity of glutathione S-transferase (GST) and glutathione peroxidase (GSH-Px) which play an important role in the detoxification of xenobiotics, was studied in the liver, kidney, heart and lung of Rhesus monkeys. Furthermore, the role of selenium (Se) in the modulation of Cd toxicity with respect to GST and GSH-Px was also evaluated. Cadmium exposure (5 mg Cd/kg body wt./day as CdCl2 for 10 weeks) to monkeys resulted in decreased GSH-Px activity in all four organs present in the order liver > kidney > heart > lung. Cadmium administration also resulted in a significant decrease in total GST activity present in the order liver > heart > kidney > lung, whereas a significant increase in the pi class GST activity was observed greatest in the heart followed by lung, kidney and liver. Oral administration of Se (0.5 mg Se/kg body wt./day as Na2SeO3 for 10 weeks) caused a significant increase in GSH-Px activity in the order liver > heart > kidney > lung. Selenium administration caused an increase in total GST activity in liver and lung but a decrease in kidney and heart. Simultaneous administration of Cd and Se resulted in an increase in total GST activity (except in lung) including the pi class activity as well as GSH-Px activity in all four tissues under study. Thus, the mechanism by which selenium decreases Cd toxicity in Rhesus monkeys, seems to rely on the protection of the enzyme systems GST and GSH-Px in the four organs, possibly by forming non-toxic cadmium selenide.

Animals↗
PubMed1993

Fluorescence postlabeling assay of DNA damage induced by N-methyl-N-nitrosourea.

We have used a new technique to assay DNA adduct by combining enzymatic digestion of DNA to nucleotides and fluorescence postlabeling. The assay relies on the selectivity of nucleotide chromatography by high-performance liquid chromatography and the sensitivity of fluorescence detection. This report describes the fluorescence postlabeling assay of N7-(N7-methyldGuo) and O6-methyl-2'-deoxyguanosine (O6-methyldGuo) in calf thymus DNA exposed to N-methyl-N-nitrosourea. Using a conventional fluorescence detector, fluorescence postlabeling assay detected 1 modified nucleotide/10(6) normal nucleotides in 100 micrograms DNA. Laser induced fluorescence detection offers a linear response of the chromatographic signal from 10(-13)-10(-16) mol fluorescent nucleotides (correlation coefficient, 0.998) improving the detection limit of the assay to 1 modified nucleotide/10(8) normal nucleotides in 10 micrograms DNA. Fluorescence postlabeling analysis of the authentic markers shows that both N7- and O6-methyldGuo can be assayed with similar detection sensitivity. However, the inherent nature of the instability of N7-methyldGuo, even under physiological conditions, makes its quantitation difficult by any postlabeling technique. O6-MethyldGuo, on the other hand, can be detected with sufficient selectivity and sensitivity by a fluorescence postlabeling assay. Quantitative efficiency of enzymatic excision and chemical postlabeling of O6-methyldGuo were validated by fluorescence postlabeling analysis of synthetic model DNA. Fluorescence postlabeling assay complements 32P-postlabeling assay for O6-methyldGuo without requiring the handling and disposal of radiolabel. Fluorescence postlabeling assay has potential, therefore, to monitor the level of O6-alkyldGuo in human DNA exposed to both environmental and chemotherapeutic alkylating agents.

Animals↗
PubMed1993

Fluorinated carbohydrates as potential plasma membrane modifiers. Synthesis of 3-deoxy-3-fluoro derivatives of 2-acetamido-2-deoxy-D-hexopyranoses.

Treatment of benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-alpha-D-allopyranoside with diethylaminosulfur trifluoride or of the 3-O-mesyl derivative with tetrabutylammonium fluoride gave the 2,3-unsaturated compound instead of the expected 3-deoxy-3-fluoro derivative. The latter was obtained when benzyl 2-acetamido-4,6-di-O-benzyl-2-deoxy-3-O-mesyl-alpha-D-allopyran oside was treated with potassium fluoride. Methyl 2-azido-4,6-O-benzylidene-2-deoxy-alpha-D-altropyranoside was converted into the 2-acetamido- and 2-phthalimido-3-O-mesyl derivatives; when treated with fluoride nucleophile, these gave only the 2,3-aziridine derivative. However, treatment of the 2-azido-2-deoxy derivative with diethylaminosulfur trifluoride gave methyl 2-azido-2,3-dideoxy-3-fluoro-alpha-D-mannopyranoside which, after reduction, deprotection, and acetylation, gave the acetylated derivative of methyl 2-acetamido-2,3-dideoxy-3-fluoro-alpha-D-mannopyranoside in excellent yield. These acetylated 3-fluoro derivatives exhibited inhibition of cell growth of murine L1210 leukemia cells in culture at micromolar concentrations.

Acetylglucosamine↗
PubMed1993

When more means less: assessing the impact of dairy 'development' on the lives and health of women in rural Rajasthan (India).

Following upon the proclaimed success of cooperative dairy schemes in other parts of India (Operation Flood based on the Amul model), the Rajasthan government is attempting a similar scheme. A key theme of the project is to bring women into the mainstream of dairy development in order to improve their economic, nutritional, and social status. For this purpose a special program was initiated to train poor rural women in 'dairy camps' on how to care for their milch animals. Successful completion of such 'camp' training then qualifies the woman for a loan to buy an animal in her name. It is hoped that a part of the milk obtained will go to the village dairy cooperative. The major aims of this program are to: remove milch animals from the cities; encourage production of more milk for the cooperative dairies; encourage modern techniques of animal care; put control of the income from milk-selling in the hands of the women who care for the animals by permitting them to own the animals and hence contribute to their 'independence' and 'development;' and to encourage self-sufficiency for the weaker sections by providing loans to the poor. Data for this paper were collected during fieldwork in a village in Alwar District, Rajasthan and specifically from observation and participation in the two-week dairy 'camp' there. Eighteen women were selected on poverty criteria to participate in the program. The general situation of these women is analyzed within the context of a critical discussion of the dairy movement in India, in general, and the intended effects on the lives of the village women, in particular, with special attention to the impact on their workload, nutritional intake and, ultimately, overall health. Concluding remarks are addressed to the broad issues of government development programs and why more of the same type of development strategies persist in the face of often-repeated failures.

Dairying↗
PubMed1993

Serodiagnosis of tuberculosis: assessment of kaolin agglutination test.

Kaolin agglutination test (KAT), for the detection of anti-tuberculophospholipid antibodies for the serodiagnosis of tuberculosis, was performed on the sera of 137 pulmonary and 276 extra pulmonary tuberculosis patients and 140 controls. The sensitivity and specificity of KAT was 86.9% and 100%, respectively, at the titre of 1:128 and more.

Agglutination Tests↗
PubMed1993

Lung carcinoma in a patient with Lucite sphere plombage thoracoplasty.

A patient with a history of pulmonary tuberculosis was treated in 1949 with Lucite sphere plombage thoracoplasty. She subsequently developed squamous cell carcinoma of the lung despite having no history of exposure to known carcinogens associated with the development of squamous cell carcinoma. The patient's lung carcinoma developed adjacent to the plombage space. Lung carcinoma has not previously been reported in association with Lucite sphere plombage.

Aged↗
PubMed1993

Evaluation of lactic dehydrogenase in cases of meningitis.

Lactic dehydrogenase (LDH) was measured serially in cerebrospinal fluid (CSF) and serum in 23 cases of meningitis (15 pyogenic and 8 tuberculous) and equal number of age and sex matched healthy controls to find out its diagnostic and prognostic significance in cases of meningitis. The LDH activity was significantly elevated in the CSF and serum (p < 0.001) in cases of pyogenic (PM) as well as tuberculous meningitis (TBM). The maximum elevation was seen on the 1st day and the activity declined thereafter. However, in 3 cases of PM and 5 cases of TBM, the LDH activity on subsequent estimations increased serially and all these cases died. Further, the basal LDH activity in the 3 cases of PM who died was significantly higher (p < 0.01) than those who survived. The rise in enzymatic activity in the CSF was significantly higher (p < 0.001) than in the serum in all the cases of meningitis. The LDH activity was significantly higher in PM as compared to TBM (p < 0.001) both in the CSF as well as the serum.

Adult↗
PubMed1992

Identification of a family of bacteriophage T4 genes encoding proteins similar to those present in group I introns of fungi and phage.

The bacteriophage T4 segA gene lies in a genetically unmapped region between the gene beta gt (beta-glucosyltransferase) and uvsX (recombination protein) and encodes a protein of 221 amino acids. We have found that the first 100 amino acids of the SegA protein are highly similar to the N termini of four other predicted T4 proteins, also of unknown function. Together these five proteins, SegA-E (similar to endonucleases of group I introns), contain regions of similarity to the endonuclease I-Tev I, which is encoded by the mobile group I intron of the T4 td gene, and to putative endonucleases of group I introns present in the mitochondria of Neurospora crassa, Podospora anserina, and Saccharomyces douglasii. Intron-encoded endonucleases are required for the movement (homing) of the intron DNA into an intronless gene, cutting at or near the site of intron insertion. Our in vitro assays indicate that SegA, like I-Tev I, is a Mg(2+)-dependent DNA endonuclease that has preferred sites for cutting. Unlike the I-Tev I gene, however, there is no evidence that segA (or the other seg genes) resides within introns. Thus, it is possible that segA encodes an endonuclease that is involved in the movement of the endonuclease-encoding DNA rather than in the homing of an intron.

Amino Acid Sequence↗
PubMed1992

Cyst fluid from human autosomal dominant polycystic kidneys promotes cyst formation and expansion by renal epithelial cells in vitro.

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive renal enlargement, culminating in renal insufficiency in over one half of affected individuals. The highly variable onset and clinical course of ADPKD may be due to factors extrinsic to the genetically defined renal cysts. In this study, cyst fluid samples from 12 nonazotemic and 18 azotemic ADPKD subjects were examined for in vitro biologic activity that promotes cellular proliferation and the secretion of fluid by renal epithelial monolayers, two pathogenetic mechanisms that have critical roles in the formation and the rate of expansion of renal cysts. Cyst fluid added to culture medium (final concentrations, 1 to 20%) caused Madin-Darby canine kidney cells and human kidney cortex (HKC) cells derived from primary cultures to form cysts in Type I collagen matrix. Cyst fluid stimulated the net transepithelial secretion of fluid by polarized monolayers composed of these same cells. Absolute levels of fluid secretory activity determined by MDCK bioassay were correlated directly with the rate of fluid secretion by HKC cell monolayers and with the extent of cyst formation by MDCK and HKC cells embedded in collagen matrix. The secretory activity of urine was negligible; secretory activity was detectable in the serum of normal and ADPKD subjects, but the levels were much lower than in cyst fluid. cAMP agonists prostaglandins E1 and E2, arginine vasopressin, and 8-Br-cAMP stimulated fluid secretion by MDCK and HKC monolayers, but these substances did not cause HKC cells to form cysts in collagen matrix, whereas cyst fluid did. Among other naturally occurring growth factors and autacoids, only epidermal growth factor and transforming growth factor alpha stimulated cyst formation by HKC cells; however, the capacity of cyst fluid to stimulate fluid secretion was not affected by treatment with antiserum to epidermal growth factor. It was concluded that potent, and possibly unique, substances in the cyst fluids of individuals with ADPKD support and augment biologic processes in renal epithelial cells that may be important in the promotion of progressive cyst expansion.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1992

Methotrexate: clinical and immunological effects in refractory rheumatoid arthritis.

Thirty five patients with refractory rheumatoid arthritis were given 7.5 mg of methotrexate (Mtx) every week. Eleven patients had to discontinue treatment either because of adverse effects or unresponsiveness. Twenty four patients showed clinical response and significant improvement in ESR and they continued Mtx for a mean of 25.24 months. Seven patients achieved clinical remission as defined by ARA criteria. Immunological parameeters including IgG, IgM, IgA, lymphocyte subsets (CD3+, CD4+, CD8+ and B), C3 and C4 however, did not show any change during this treatment in any of the groups upto 6 months. There was a significant fall in the erythrocyte sedimentation rate (ESR), c-reactive protein (CRP) and rheumatoid factor (RF) levels in responders only.

Administration, Oral↗