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Biomedical subjects

S K Sharma

Publications and source records attributed to S K Sharma.

At least 271 records · Page 15Linked to original sources
PubMed1996

Comparison of two methods for determining in vitro intestinal absorption of nutrients using rats fed different diets.

Absorption of sucrose, glucose, leucine and aspartate was studied using intestinal everted sac of rats fed on french bean diets namely PDR-14, HUR-137 and HUR-15 using casein as a control. Absorption of nutrients was monitored spectrophotometrically and by 14C radio assay of metabolites using scientillation counting. The absorption pattern of amino acids was found to be similar but of glucose and sucrose differed. Glucose was found to be more absorbed than sucrose in spectrophotometer assay and the pattern reversed in radio assay. Absorption of sucrose and leucine were higher by rats fed on HUR-137 diet and similarly, more aspartate was absorbed when fed on HUR-15 diet as demonstrated by both the methods. Rats fed on HUR-137 diet exhibited higher glucose absorption as shown by spectrophotometric assay, but rats on HUR-15 diet by radio assay. Absorption of nutrients differed significantly between casein and french beans.

Amino Acids↗
PubMed1996

Mechanism of action of NIM-76: a novel vaginal contraceptive from neem oil.

The present study was undertaken to elucidate the mechanism of spermicidal action of NIM-76, a fraction isolated from neem oil. The spermicidal activity of NIM-76 was confirmed using a fluorescent staining technique. NIM-76 was found to affect the motility of the sperm in a dose-dependent manner. Supplementation of pentoxifylline, which is known to enhance the motility of the sperm, could not prevent the spermicidal action of NIM-76. There was a gradual leakage of cytosolic LDH from the sperm in the presence of NIM-76. Electron microscopic studies revealed the formation of pores and vesicles over the sperm head, indicating the damage to the cell membrane. Membrane fluidization studies did not reveal any significant change in the fluidity of sperm cell membrane structure.

Animals↗
PubMed1996

Chemoprevention of carcinogen-DNA binding: the relative role of different oxygenated substituents on 4-methylcoumarins in the inhibition of aflatoxin B1-DNA binding in vitro.

Eighteen 4-methylcoumarins bearing methoxy/hydroxy/acetoxy functionalities have been reported to effectively inhibit the rat liver microsome-mediated aflatoxin B1-DNA binding in vitro. The contribution of functionality on coumarin nucleus towards the inhibition of AFB1-DNA binding is in the order acetoxy > hydroxy > methoxy. The results illustrate the structure-activity relationship.

Aflatoxin B1↗
PubMed1996

Altered biodistribution of an antibody--enzyme conjugate modified with polyethylene glycol.

Polyethylene glycol modification of the antibody--enzyme conjugate, F(ab')2-A5B7-CPG2, extends its duration in the circulation of nude mice bearing human colonic cancer xenografts (LS174T). Increased concentration of modified conjugate is achieved in the tumour, but residual non-specific enzyme concentrations in normal tissue and blood demonstrate the fundamental requirement to remove or inactivate non-specifically held enzyme in this system.

Animals↗
PubMed1996

Calculogenic potential of galactose and fructose in relation to urinary excretion of lithogenic substances in vitamin B6 deficient and control rats.

OBJECTIVE: Calculogenic potential of refined sugars galactose and fructose was examined in vitamin B6 deficient and control rats in terms of their capacity to increase urinary excretion of lithogens. METHODS: Male albino rats were fed vitamin B6 deficient diet with 51.7% sucrose+ starch or galactose or fructose as the source of carbohydrate. Pair-fed controls were maintained for all the groups for a period of four weeks. Twenty-four hour urine samples obtained at weekly intervals were analyzed for creatinine, calcium, oxalate, phosphate and uric acid. Microscopic urinalysis was performed at the end of the study. RESULTS: Urinary calcium excretion increased with respect to baseline in all groups except vitamin B6 control group. On day 28, galactose and fructose-fed rats demonstrated significant hypercalciuria as compared to the sucrose + starch fed group. Vitamin B6 deficient rats (irrespective of the sugar fed) excreted significantly greater urinary calcium compared to pair-fed controls. Oxalate excretion was significantly increased in rats fed galactose compared to those fed fructose or sucrose + starch. Vitamin B6 deficiency further increased oxalate excretion by 1.5, 1.9 and 1.7 fold in sucrose + starch, fructose or galactose fed animals, respectively. Urinary uric acid excretion was enhanced only in fructose-fed rats. There was no change in urinary excretion of creatinine and phosphate in different experimental and control groups. Increased urinary saturation with lithogens caused pronounced crystalluria in all the vitamin B6 deficient groups as well as galactose control group. CONCLUSION: The results suggest galactose ingestion is associated with a greater propensity to form calcium oxalate kidney stones than fructose. Calculogenic potential of galactose and fructose is further enhanced in vitamin B6 deficiency.

Animals↗
PubMed1996

Isolated collagenoma: a case report with a review of connective tissue nevi of the collagen type.

A 22-year-old male had had five skin colored tumorous growths on the mid-palm, ring and little fingers of the right hand for the last 15 years. Histopathological examination with hematoxylin and eosin and special stains confirmed the diagnosis of connective tissue nevi of collagen type. There were no associated cutaneous or systemic findings; thus the case was designated as isolated collagenoma. A review of connective tissue nevi of the collagen type is presented.

Adult↗
PubMed1996

Tropical pulmonary eosinophilia: a comparative evaluation of plain chest radiography and computed tomography.

Plain chest radiography and computed tomography (CT) of the chest were performed on 10 patients with tropical pulmonary eosinophilia (TPE). Chest radiographs revealed bilateral diffuse lesions in the lungs of all the patients with relative sparing of lower lobes in one patient. However, computed tomography revealed bilateral diffuse lung lesions in all of the patients with relative sparing of lower lobes in three patients. In seven (70%) of the 10 patients, CT provided additional information. Computed tomography was found to be superior for the detection of reticulonodular pattern, bronchiectasis, air trapping, calcification and mediastinal adenopathy. No correlation was found between pulmonary function and gas exchange data using CT densities. There was also no correlation between the absolute eosinophil count (AEC) and the radiological severity of lesions. In six patients, high-resolution CT (HRCT) was performed in addition to conventional CT (CCT), and nodularity of lesions was better appreciated in these patients. It is concluded from this study that CT is superior to plain radiography for the evaluation of patients with TPE. However, more work needs to be done to substantiate the results of the present study.

Adolescent↗
PubMed1996

An ultrasonographic study of Peyronie's disease.

A study was undertaken to determine the usefulness of ultrasonography as an investigative tool, and its role in deciding the management of Peyronie's disease. Fifteen patients with Peyronie's disease were studied by ultrasonography. The plaque could be demonstrated in all patients. The dimensions of the plaque varied from less than 1 cm to more than 7 cm in length and 2-4mm in thickness. The disease was active in 26% of the patients, as indicated by the presence of hypoechoic areas around a central region of hyperechoism. Ultrasonogram was more accurate than clinical assessment in delineating the extent of lesions. In one-third of the patients, sonography demonstrated the plaques to be more extensive than had been detected by clinical examination. Calcification and activity of disease (which are clearly defined by ultrasonogram) are determining factors in the management of Peyronie's disease. This information allows the surgeon to select the modality of treatment, the timing of surgery and extent of excision. Thus, ultrasonography plays a vital role in the preliminary investigation and management of Peyronie's disease.

Humans↗
PubMed1996

Computed tomography in miliary tuberculosis: comparison with plain films, bronchoalveolar lavage, pulmonary functions and gas exchange.

Computed tomography (CT) of the chest, pulmonary function tests, bronchoalveolar lavage (BAL) and arterial blood gas analysis were performed in 26 patients with non-HIV miliary tuberculosis (MTB). CT was repeated after treatment in 11 patients. Nodular lesions were characteristically seen on CT. CT showed discrete and fine nodules in five patients in whom the lesions appeared to be larger than miliary on chest X-rays. Coalescing nodular lesions were noted on chest X-rays (n = 7) and CT (n = 18). Consolidation (n = 6), cavitation (n = 4), fibrosis (n = 9) and air trapping (n = 14) were detected on CT only. During follow up, air trapping increased (n = 14) and in some patients it appeared for the first time (n = 2). Lymph node enlargement and calcification were seen on both chest X-rays (n = 9 and n = 3, respectively) and CT (n = 12 and n = 7, respectively). Pleural involvement was also seen in chest X-rays (n = 4) and CT (n = 5). Total lung capacity was higher in patients with a chest X-ray score > 10. Similarly a higher total cell count in BAL fluid was observed in patients with a CT score > 10. It is concluded from this study that CT is superior to chest X-rays in detecting nodular lesions, lymphadenopathy and air trapping in patients with MTB.

Adult↗
PubMed1996

(Alkylamino) piperidine bis(heteroaryl)piperizine analogs are potent, broad-spectrum nonnucleoside reverse transcriptase inhibitors of drug-resistant isolates of human immunodeficiency virus type 1 (HIV-1) and select for drug-resistant variants of HIV-1IIIB with reduced replication phenotypes.

The (alkylamino)piperidine bis(heteroaryl)piperizines (AAP-BHAPs) are a new class of human immunodeficiency virus type 1 (HIV-1)-specific inhibitors which were identified by targeted screening of recombinant reverse transcriptase (RT) enzymes carrying key nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance-conferring mutations and NNRTI-resistant variants of HIV-1. Phenotypic profiling of the two most potent AAP-BHAPs, U-95133 and U-104489, against in vitro-selected drug-resistant HIV-1 variants carrying the NNRTI resistance-conferring mutation (Tyr->Cys) at position 181 of the HIV-1 RT revealed submicromolar 90% inhibitory concentration estimates for these compounds. Moreover, U-104489 demonstrated potent activity against BHA-P-resistant HIV-1MF harboring the Pro-236->Leu RT substitution and significantly suppressed the replication of clinical isolates of HIV-1 resistant to both delavirdine (BHAP U-90152T) and zidovudine. Biochemical and phenotypic characterization of AAP-BHAPresistant HIV-1IIIB variants revealed that high-level resistance to the AAP-BHAPs was mediated by a Gly-190->Glu substitution in RT, which had a deleterious effect on the integrity and enzymatic activity of virion-associated RT heterodimers, as well as the replication capacity of these resistant viruses.

Antiviral Agents↗
PubMed1996

Identification of a cyclin-cdk2 recognition motif present in substrates and p21-like cyclin-dependent kinase inhibitors.

Understanding how cyclin-cdk complexes recognize their substrates is a central problem in cell cycle biology. We identified an E2F1-derived eight-residue peptide which blocked the binding of cyclin A and E-cdk2 complexes to E2F1 and p21. Short peptides spanning similar sequences in p107, p130, and p21-like cdk inhibitors likewise bound to cyclin A-cdk2 and cyclin E-cdk2. In addition, these peptides promoted formation of stable cyclin A-cdk2 complexes in vitro but inhibited the phosphorylation of the retinoblastoma protein by cyclin A- but not cyclin B-associated kinases. Mutation of the cyclin-cdk2 binding motifs in p107 and E2F1 likewise prevented their phosphorylation by cyclin A-associated kinases in vitro. The cdk inhibitor p21 was found to contain two functional copies of this recognition motif, as determined by in vitro kinase binding/inhibition assays and in vivo growth suppression assays. Thus, these studies have identified a cyclin A- and E-cdk2 substrate recognition motif. Furthermore, these data suggest that p21-like cdk inhibitors function, at least in part, by blocking the interaction of substrates with cyclin-cdk2 complexes.

Amino Acid Sequence↗
PubMed1996

The effect of an anti-CD3 monoclonal antibody on bleomycin-induced lymphokine production and lung injury.

Acute lung injury was produced in C57BL/6 mice by the intratracheal (i.t.) administration of bleomycin (BLM). Following injection of 0.1 U BLM, CD3+ lymphocytes and the production of the T-helper-1 (Th1) lymphokines interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were increased in lung and lymph nodes. The production of the Th2 cytokine IL-4 by lung lymphocytes was decreased. Intraperitoneal (i.p.) injection of a rat antimurine CD3 (YCD3) monoclonal antibody (mAb) blocked the accumulation of pulmonary CD3+ cells for up to 14 d and effectively suppressed IL-2 and IL-4 but not IFN-gamma production by lung lymphocytes throughout the protocol. Secretion of all of the above lymphokines by lymph node cells was inhibited by YCD3 treatment. Administration of YCD3 diminished pulmonary fibrosis and increased survival (p < 0.01) following BLM administration compared with mice treated with an isotype-matched control mAb. Initiating treatment with YCD3 at Days 5-7 following BLM also decreased pulmonary fibrosis and significantly reduced mortality (p < 0.02). We conclude that BLM yields a potentially lethal fibroinflammatory response in the lung that is markedly diminished by antagonizing the functional activities of CD3+ cells in vivo.

Animals↗
PubMed1996

Mosquito breeding in relation to aquatic vegetation and some physico-chemical parameters in rice fields of central Gujarat.

Mosquito breeding in relation to aquatic vegetation and certain physico-chemical parameters was studied in rice fields of Kheda district in central Gujarat. A total of 14 anopheline and 15 culicine species were encountered in close association with different types of aquatic vegetation in different proportions. Among anophelines, Anopheles annularis, An. nigerrimus, An. subpictus and An. tessellatus were of general distribution and were found associated with each aquatic vegetation. An. culicifacies showed poor association with most of the aquatic weeds. Maximum number of anophelines were found associated with algae. Culex vishnui sub-group predominated among culicines and showed frequent association with Ceratophyllum, Hydrilla and algae. Physico-chemical parameters also exerted some impact on mosquito larval population.

Agriculture↗
PubMed1996

Studies on Plasmodium vivax relapse pattern in Kheda district, Gujarat.

Relapse pattern in P. vivax malaria was studied in five villages of Nadiad taluka, Kheda district, Gujarat. P. vivax cases treated with 600 mg chloroquine and in combination with 50 mg pyrimethamine (adult dose) yielded 28.31 and 27.73% relapse rate respectively. While relapse rate of 5.78% was observed with five day course of 75 mg primaquine (15 mg/day) administered as radical treatment. Relapse rate in 5-10 yr of age group was comparatively more than other age groups. There was no noticeable difference in relapse rates among male and female. The short-term relapse with a lag period of 2-3 months was significantly higher in this area. The longest relapse with an interval of 17 months was found in one case treated with chloroquine along with pyrimethamine. However, primaquine regimen prevented consecutive relapses. Primaquine has been found adequate to prevent relapse in more than 90% vivax cases, while efficacy of chloroquine-pyrimethamine and chloroquine alone was almost comparable. A high proportion of relapse may be minimized, if 5-days radical treatment is given at appropriate time.

Adolescent↗
PubMed1996

Socio-economic aspects of malaria in Kheda district, Gujarat.

Study on the socio-cultural factors and economic loss due to malaria in rural and urban areas of Kheda district, Gujarat revealed that factors such as education, profession, income, housing pattern, social groups, water storage and treatment seeking behaviour play an important role in malaria transmission. However, the difference of these components in respect to malaria cases between rural and urban areas were statistically insignificant. Mean monetary loss per malaria episode was found to be more in urban area (Rs. 393.59) as compared to rural (Rs. 157.59). The study also suggests the importance of socio-cultural factors in implementing any community health programme. Health education is needed to make the people aware and health conscious for prevention of disease at their own level.

Adolescent↗