Browsing by Author "S. Mitra"

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A new dihydrazone based "turn on" fluorescent sensor for Zn(II) ion in aqueous medium
(Elsevier, 2015) R. Borthakur; U. Thapa; M. Asthana; S. Mitra; K. Ismail; R.A. Lal
A new simple dihydrazone based colorimetric and fluorescent "turn-on" chemosensor (disalicyladehyde succinoyldihydrazone, I) for Zn(II) was designed and synthesized. The photophysical behavior of the ligand and metal coordinated complex was characterized by steady state and time-resolved fluorescence, density functional theory calculation in combination with 1H NMR and mass spectroscopy results. The compound acts as a highly selective and sensitive detector of Zn(II) in aqueous medium with almost six times increase in fluorescence intensity. The optimum condition for sensing ability of I with a detection limit of ca. 2 μM of Zn(II) was found at solution pH 8.6 and at excitation wavelength of 380 nm. The other interfering elements, including Cd(II), show either no or very little change in fluorescence intensity under similar experimental conditions. © 2014 Elsevier B.V. All rights reserved.
Angiogenesis and histologic scoring in prostatic carcinoma - A valuable cost effective prognostic indicator
(2004) M. Kumar; V. Tandon; P.B. Singh; S. Mitra; N. Vyas
Objective: To find any correlation between microscopic angiogenesis grading system (MAGS) score and Gleason score and serum prostate specific antigen (S.PSA) in carcinoma of prostate. Study design: Examination of 30 patients with prostatic carcinoma compared with an age matched control group of 30 patients having histopathologically proven benign prostatic Hyperplasia. The Preoperative serum PSA level was determined in all patients. Histopathological examination for MAGS score was done in all patients and Gleason scoring was done for cases of prostatic carcinoma. Result: MAGS score had a definite correlation with Gleason score (Correlation coefficient, r = 0.84, p = 0.008). Studying the relationship between MAGS score and S.PSA, a statistically significant difference is found between S.PSA levels in study and control groups, and in the three MAGS score groups namely 21-30, 31-40 and 41-50. Conclusion: Gleason score and MAGS score are well related to each other. As tumor becomes more poorly differentiated with rising Gleason score, it would also have increased number of capillaries and higher grade endothelial cytology leading to a higher MAGS score.
Coexistence of Folded and Extended Conformations of a Tripeptide Containing α,α-Di-n-propylglycine in Crystals
(1994) S. Prasad; S. Mitra; E. Subramanian; D. Velmurugan; R.B. Rao; P. Balaram
The crystal structure of the tripeptide Boc-Leu-Dpg-Val-OMe (Dpg, α, α-di-n-propylglycine) reveals the coexistence of two distinct backbone conformations. In molecule A the Dpg residue adopts a fully extended conformation (φ = 76.0°, ψ =180.0°) while in molecule B a left handed helical conformation (φ = 62.8°, ψ = 39.6°) is observed. Molecule B adopts a folded structure corresponding to a highly distorted Type II β-turn conformation, which lacks an intramolecular 4 → 1 hydrogen bond. In contrast, molecule A has an open, extended conformation. The results demonstrate that both fully extended and helical conformations are energetically accessible to the Dpg residue. © 1994 Academic Press. All rights reserved.
Effect of ethanolic extract of root of Pongamia pinnata (L) pierre on oxidative stress, behavioral and histopathological alterations induced by cerebral ischemia-reperfusion and long-term hypoperfusion in rats
(2007) M. Raghavendra; Anshuman Trigunayaf; R.K. Singh; S. Mitra; R.K. Goel; S.B. Achaiya
Possible effect of an ethanolic root extract of Pongamia pinnata (L) Pierre (P. pinnata) on oxidant-antioxidant status and histopathological changes in acute ischemia-reperfusion injury in the rat forebrain have been investigated. Further, its effect was also assessed on long-term cerebral hypoperfusion- induced changes in anxiety, cognitive and histopathological parameters. Cerebral post-ischemic reperfusion is known to be associated with generation of free radicals. In the present study, bilateral common carotid artery occlusion (BCCAO) for 30 min followed by 45 min reperfusion produced increases in lipid peroxidation, superoxide dismutase (SOD) activity and a fall in the total tissue sulfhydryl (T-SH) levels. The ethanolic extract of roots of P. pinnata (50 mg kg" , po for 5 days) attenuated the ischemia-reperfusion-induced increase in lipid peroxidation, SOD activity and a fall in T-SH levels. The extract also ameliorated histopathological changes and inflammatory cell infiltration in the frontoparietal region of the rat brain. The extract (50 mg kg" , po for 15 days) was also found to alleviate the long-term hypoperfusion-induced anxiety and listlessness (open field paradigm). There was an improvement of learning and memory deficits (Morris' water maze testing). It also attenuated reactive changes in forebrain histology like gliosis, lymphocytic infiltration, astrocytosis and cellular edema. Results suggest protective role of P. pinnata in ischemia-reperfusion injury and cerebrovascular insufficiency states.