Rakesh Sharma

Publications (66) View all

• Article: In vivo genotoxicity evaluation of a plant based antiarthritic and anticancer therapeutic agent Boswelic acids in rodents.

  R Sharma, S Singh, G D Singh, A Khajuria, T Sidiq, S K Singh, G Chashoo, S S Pagoch, A Kaul, A K Saxena, R K Johri, S C Taneja
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  ABSTRACT: The genotoxic potential of anti-inflammatory/anti-arthritic and anticancer plant based drug molecule Boswelic acids (BA) was studied by in vivo system. Systematic literature survey revealed that studies on the genotoxicity of BA are not available. Although reports on genotoxicity of Boswellia serrata dry extract and modified 3-O-acetyl-11-keto-beta-boswelic acid are available and these studies were conducted in in vitro systems. The earlier general toxicity study of BA has been conducted by us, revealed it to be non toxic. The genotoxicity was carried out in Wistar rats using different cytogenetic assay system-abnormalities viz. chromosomal aberrations; sperm morphology, micronuclei and comet assays. Six groups of animals, each comprised of five rats, were taken for each study. Group1-4 received BA at 125, 250, 500 and 1000 mg/kg p.o., respectively prepared as 2% gum acacia suspension, fifth group received a positive control cyclophosphamide (CP) 40 mg/kg p.o. or metronedazole (MTZ) 130 mg/kg p.o. or mercuric chloride (HgCl(2)) 0.864 mg/kg p.o. (as per the experiment requirement) whereas the sixth group kept as vehicle control. The results on the bases of the data obtained revealed that BA is quite safe as it did not show any genotoxicity at any dose level up to 1000 mg/kg. The positive controls used in different experiments showed highly significant abnormal cytogenetic changes in comparison to the control group.
  Phytomedicine: international journal of phytotherapy and phytopharmacology 09/2009; 16(12):1112-8. · 2.17 Impact Factor
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  Available from: Rakesh Sharma

  Article: Increased myocardial wall thickening as index of viability assessment: a preliminary report on delayed contrast MRI.

  Rakesh Sharma, Jose K Katz
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  ABSTRACT: Regional wall thickening measurement by delayed contrast MRI may assess myocardial viability and functional recovery of ischemic cardiomyopathy. Delayed contrast MRI data was used in 40 patients with significant coronary artery disease and severe left ventricular dysfunction. Regional wall thickening on follow-up MRI served as an index of functional recovery in patients receiving revascularization. For comparison, myocardial viability was assessed by MRI and 201Tl SPECT in 10 patients using a 17-segment method. On 480 segments, MRI hyperintensities showed positive correlation with 201Tl reduction (r = 0.71, p < 0.0001) in the inferior wall and apex. Delayed MRI detected myocardial viability better than 201Tl SPECT. Delayed contrast-enhanced MRI showed diagnostic accuracy 65%, sensitivity 95%, specificity 25%, positive predictive value 65% and negative predictive value 75%, whereas 201Tl SPECT showed diagnostic accuracy 54%, sensitivity 72%, specificity 25%, positive predictive value 52% and negative predictive value 54%. Areas under the ROC curves by MRI and 201Tl SPECT were 0.59 +/- 0.04, 0.52 +/- 0.05, respectively (p = 0.07). The viability concordance was 80% between 201Tl SPECT and MRI. Delayed contrast-enhanced MRI may detect the inferior wall thickening and apex as an index of viable myocardium better than 201Tl SPECT. Myocardial viability may predict functional recovery after revascularization in ischemic cardiomyopathy.
  Contrast Media & Molecular Imaging 01/2009; 4(1):37-41. · 3.33 Impact Factor
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  Available from: fsu.edu

  Article: Microimaging of hairless rat skin by magnetic resonance at 900 MHz.

  Rakesh Sharma
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  ABSTRACT: Quantitative imaging of the rat skin was performed using magnetic resonance imaging (MRI) at 900 MHz. A number of imaging techniques utilized for multiple contrast included magnetization transfer contrast, spin-lattice relaxation constant (T1-weighting), combination of T2-weighting with magnetic field inhomogeneity (T2*-weighting), magnetization transfer weighting and diffusion tensor weighting. These were used to obtain 2D slices and 3D multislice-multiecho images with high magnetic resonance contrast. These 2D and 3D imaging techniques were combined to achieve high-resolution MRI. Oil-water phantom showed distinct fat-water contrast. The dermis and epidermis, including the stratum corneum remnants, of nude rat skin were distinct due to their proton magnetic resonance as a result of proton interactions with the skin interstitial tissue. Combined details obtained from high-resolution, high-quality ex vivo skin images with different multicontrast characteristics generated better differentiation of skin layers, sublayers and significant correlation (r(2)=0.4927 for MRI area, r(2)=0.3068 for histology area; P<.0148) of MR data with co-registered histological areas of the epidermis as well as the hair follicle. The multiple contrast approach provided a noninvasive ex vivo MRI visualization with semi-quantitative assessment of the major skin structures including the stratum corneum remnants, epidermis, hair, papillary dermis, reticular dermis and hypodermis.
  Magnetic Resonance Imaging 09/2008; 27(2):240-55. · 1.99 Impact Factor
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  Available from: Rakesh Sharma

  Article: Taxotere chemosensitivity evaluation in mice prostate tumor: validation and diagnostic accuracy of quantitative measurement of tumor characteristics by MRI, PET, and histology of mice tumor.

  Rakesh Sharma, Jose K Katz
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  ABSTRACT: Increased PET and MRI image intensities of mouse prostate tumors were correlated with histostaining tumor characteristics. The hypothesis was that increased intracellular sodium microMRI signal intensities and flouro-2-deoxy-glucose utilization by microPET in apoptosis rich regions in tumors were positively correlated as chemosensitivity assay of Taxotere. The PC-3 cancer cell line induced prostate tumor MRI and PET images and histology slices were digitally captured and compared in pre- and post-Taxotere treated tumors. The optimization of inversion recovery MRI parameters was done to generate sodium images of phantom. The (18)FDG biotransformation was optimized to measure PET image intensities. A criterion was developed to evaluate malignancy by histology. For correlation, regression analysis was done using imaging, histology, and immunostaining data from PC3 tumor after 24 and 48 hours post-Taxotere treatment. Apoptosis indices were calculated by histostaining and ss-DNA antibody assay. Sodium MRI and PET signal intensity distributions were comparable at specific locations relatively and measured in tumor tissue regions. In tumors, Taxotere induced an increase in intracellular sodium MRI signal 30% (p<0.001) with decreased tumor size (20%; p<0.001) and micro-PET showed FDG uptake increase 15% (p<0.001) with decreased tumor size (10%; p<0.001) than that of control tumors after 24 hours. Histological features indicated tumor risk (high 'intracellular/extracellular ratio', high mitotic index, and apoptotic index), decreased tumor viability (reduced mitotic figures, reduced diploidy or aneuploidy, and proliferation index) after Taxotere treatment. These features in co-registered intracellular sodium, microPET hypermetabolic, and monoclonal antibody (ss-DNA) sensitive regions showed (% difference > 6%). Apoptosis rich regions showed characteristic nuclei with S phase DNA histogram, appearing brighter on IC-Na images and mild active on PET images (sensitivity=65%; specificity=70%). In conclusion, MRI and PET multimodal imaging may be rapid non-invasive chemosensitivity assay to monitor the drug anticancer effect.
  Technology in cancer research & treatment 07/2008; 7(3):175-85. · 2.02 Impact Factor
• Article: TEXTURAL PROFILE ANALYSIS OF SUNFLOWER–SESAME KERNEL CONFECTION (CHIKKI)

  R.K. GUPTA, A. SHARMA, R. SHARMA
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  ABSTRACT: Models capable of predicting textural quality of sunflower–sesame kernel confection (chikki) have been developed using response surface methodology. The model can be used to determine the effect of sunflower–sesame kernel proportions on texture profile analysis (TPA) parameters of the product. The quality attributes measured were hardness, cohesiveness, springiness, chewiness and resilience, whose values varied from 100–183 N, 1.01–2.82, 1.00–1.18, 21.7–495.1 N and 0.297–0.436, respectively. The highest values of hardness, chewiness and resilience were attained for the snacks prepared using jaggery (brown sugar) : sunflower kernel : sesame kernel in the ratio of 50:35:25. The highest values of cohesiveness and springiness were observed with 50:25:15 (jaggery : sunflower : sesame) proportions. The sensory term overall acceptability of the snacks is significantly correlated with instrumental cohesiveness, springiness and chewiness, which are the desired quality attributes of the snacks.PRACTICAL APPLICATIONSPopularizing sunflower kernel in the diet can help combat protein–calorie malnutrition in children to a certain extent in developing countries. This research may provide an opportunity to consider sunflower kernel as an ingredient in new products by manufacturers of baked goods and snack foods. The objective of the study was to quantify characteristics of textural profile of sunflower–sesame kernel chikki prepared using various proportions of sunflower and sesame kernels. Models developed using response surface methodology for predicting the textural quality of snacks can be used to determine the effect of sunflower–sesame kernel proportions on texture profile analysis parameters of the product. The confection (chikki) prepared taking jaggery, sunflower and sesame kernels as ingredients is an organoleptically accepted product.
  Journal of Texture Studies 01/2007; 38(1):153 - 165. · 0.82 Impact Factor