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Biomedical subjects

S K Dutta

Publications and source records attributed to S K Dutta.

At least 19 recordsLinked to original sources

Binding of diclofenac sodium with bovine serum albumin at different temperatures, pH and ionic strengths.

The study was designed to examine the binding of diclofenac sodium with bovine serum albumin (BSA) at different temperatures (20 degrees, 30 degrees and 40 degrees C), pH (6.4, 7.4 and 8.4) and ionic strengths (micro = 0.1, 0.2 and 0.3) by means of equilibrium dialysis method. The concentration of diclofenac sodium was maintained at wider range from 15 to 900 micromole/l and BSA concentration was maintained at 61.5 micromole/l. The data obtained were interpreted by nonlinear regression method using Graphpad prism software. The analysis showed that the interaction between diclofenac sodium with BSA results in two-site saturable binding. A decrease in association constant was observed with increasing temperature. The average standard free energy change (deltaGdegrees) value was -7.07 (site I) and -4.2 (site II) Kcal/mol. The standard enthalpy change (deltaHdegrees) and the standard entropy change (deltaSdegrees) were -7.8 Kcal/mole, -2.35 cal/mole (site I) and -7.4 Kcal/mole, -10.5 cal/mole (site II), respectively. The negative enthalpy change suggested the binding between diclofenac sodium and the binding sites of BSA were spontaneous and exothermic. The negative value of deltaHdegrees and deltaSdegrees indicated hydrogen bonding and van der Waal's force was the major mechanism for diclofenac sodium and BSA interaction. Increase in pH and ionic strength also caused decrease in association constant of diclofenac sodium and BSA binding.

Animals↗

Molecular evidence of genetic modification of Sinorhizobium meliloti: enhanced PCB bioremediation.

The genome of the nitrogen-fixing soil bacterium Sinorhizobium meliloti does not possess genes for bioremediation of aromatic pollutants. It has the well-known ability to interact specifically with the leguminous alfalfa plant, Medicago sativa. Our previous work has shown enhanced degradation of the nitroaromatic compound 2,4-dinitrotoluene (DNT) when a plasmid containing degradative genes was introduced in it. In this study we report molecular evidence of the transfer of a polychlorinated biphenyl (PCB)-biodegradative plasmid pE43 to S. meliloti strain USDA 1936. Several standard analytical tests and plant growth chamber studies were conducted to test the ability of S. meliloti to degrade 2',3,4-PCB congener. Alfalfa plant alone was able to degrade 30% of PCBs compared with control. No enhanced dechlorination was noted when alfalfa plant was grown with wild-type S. meliloti, and when alfalfa plant was grown with the S. meliloti electrotransformants (genetically modified) dechlorination of PCBs was more than twice that when alfalfa plant was grown with wild-type S. meliloti. When alfalfa plant was grown with uncharacterized mixed culture (containing nodule formers), almost equally significant PCB degradation was observed. The significance of this work is that the naturally occurring nitrogen-fixing soil bacterium S. meliloti (genetically modified) has the ability to enhance fertility of soil in association with the leguminous alfalfa plant while simultaneously enhancing bioremediation of PCB-contaminated soils. Enhanced bioremediation of PCB and robust alfalfa plant growth was also noted when uncharacterized mixed cultures containing alfalfa plant nodule formers were used.

Biodegradation, Environmental↗

Spectroscopy of three-particle entanglement in a macroscopic superconducting circuit.

We study the quantum mechanical behavior of a macroscopic, three-body, superconducting circuit. Microwave spectroscopy on our system, a resonator coupling two large Josephson junctions, produced complex energy spectra well explained by quantum theory over a large frequency range. By tuning each junction separately into resonance with the resonator, we first observe strong coupling between each junction and the resonator. Bringing both junctions together into resonance with the resonator, we find spectroscopic evidence for entanglement between all 3 degrees of freedom and suggest a new method for controllable coupling of distant qubits, a key step toward quantum computation.

Journal Article↗

Skin cancers in chronic arsenic toxicity--a study of predictive value of some proliferative markers.

Prolonged exposure to arsenic contaminated water produces various clinical features, cutaneous features e.g. melanosis, keratosis and cancers being very common. Evaluation of such lesions by proliferative markers can provide useful information in regards to the biological behaviour of the lesions. Thus, cases with high proliferative status can be ominous sign for development of cancers. We studied skin biopsy of 42 cases. These were evaluated with AgNOR score and PCNA stain, in addition to H & E examination. Here, invasive cancer cases had mean AgNOR score of 3.56, those with severe dysplasia had 3.0, moderate and mild dysplasia scored 1.73, benign changes had mean score of 1.35 while normal control cases had 1.08. PCNA index in cancers was above 50, that of severe dysplasia 25-30, mild to moderate dysplasia 1.0-5.0, those with benign changes 0.5 -1.0 and normal control had LI of less than 0.5%. PCNA has the advantage of less chance of observer error over AgNOR stain.

Adolescent↗

Simultaneous induction of ectopic pelvic zone and duplication of regenerated limbs in tadpoles of Polypedates maculatus by vitamin A.

With a view to determine ectopic limb developing capacity along with normal hind limb regeneration in response to vitamin A palmitate in well-differentiated hind limb stage tadpoles of P. maculatus, higher doses of vitamin A (30 IU/ml and 20 IU/ml) were administered for a longer period (120 hr) to the tadpoles following tail amputation through middle and hind limb amputation through middle of thigh. Simultaneous development of ectopic pelvic zone was observed along with hind limbs from the cut end of tail and duplication of regenerated hind limbs in the same tadpole for the first time. Besides, development of double ectopic pelvic girdle was also reported in one case. Results also indicate that induction of pelvic zone and duplication of regenerated limbs are concentration dependent.

Animals↗

Coulomb expansion of laser-excited ion plasmas.

We determine the electric field in mm-sized clouds of cold Rb+ ions, produced by photoionization of laser-cooled 87Rb atoms in a magneto-optical trap, using the Stark effect of embedded Rydberg atoms. The dependence of the electric field on the time delay between the ion plasma production and the probe of the electric field reflects the Coulomb expansion of the plasma. Our experiments and models show expansion times <1micros.

Journal Article↗

Feedback control of atomic motion in an optical lattice.

We demonstrate a real-time feedback scheme to manipulate wave-packet oscillations of atoms in an optical lattice. The average position of the atoms in the lattice wells is measured continuously and nondestructively. A feedback loop processes the position signal and translates the lattice potential. Depending on the feedback loop characteristics, we find amplification, damping, or an entire alteration of the wave-packet oscillations. Our results are well supported by simulations.

Journal Article↗

Sheep form of leucocyte function antigen-3 (T11TS) exerts immunostimulatory and anti-tumor activity against experimental brain tumor. A new approach to biological response modifier therapy.

In order to establish the mechanism(s) of immunomodulatory and anti-tumor properties of sheep erythrocytes (SRBC), the T11 target structure (T11TS) or CD58 molecule as a pertinent component of SRBC was isolated, purified and finally administered in rats with experimentally induced brain tumor. Results showed inhibition and/or abrogation of tumor growth. Subsequent studies on cellular immunity also revealed potentiation of lymphocytes and PMNs at peripheral level. Presence of activated lymphocytes as revealed through flowcytometric analysis of CD25 expression evidenced infiltration of activated lymphocytes in the brain tumor tissues. The analysis of data suggests that T11TS or sheep form of LFA3 is capable of inhibiting/preventing tumor growth in rat brain by way of immunopotentiation (CMI) at the peripheral immune system and thereby facilitating infiltration of the activated lymphocytes into the brain cavity through the blood brain barrier.

Animals↗

High-angular-momentum states in cold Rydberg gases.

Cold, dense Rydberg gases produced in a cold-atom trap are investigated using spectroscopic methods and time-resolved electron counting. Optical excitation on the discrete Rydberg resonances reveals long-lasting electron emission from the Rydberg gas ( >20 ms). Our observations are explained by lm-mixing collisions between Rydberg atoms and slow electrons that lead to the population of long-lived high-angular-momentum Rydberg states. These atoms thermally ionize slowly and with large probabilities.

Journal Article↗

Diagnostic accuracy of simpson atherectomy catheter biopsy in detecting pancreaticobiliary malignancy.

OBJECTIVE: Impressive advances have been made in imaging the biliary tree by various modalities in the last few decades. However, the histological diagnosis of stenosing lesions in the biliary ductal system has remained difficult and unreliable. Application of Simpson atherectomy catheter biopsy in obtaining accurate histological diagnosis of bile duct lesions appears promising. The purpose of our study was to determine the clinical accuracy of the Simpson atherectomy catheter biopsy in the evaluation of bile duct strictures. METHODS: A retrospective study of medical records of patients who underwent bile duct biopsy by atherectomy catheter was conducted between 1991 and 1999. During this period, 53 patients underwent 56 endoluminal bile duct biopsies with an atherectomy catheter as part of an obstructive jaundice workup. Histological diagnosis on biopsy was confirmed by subsequent surgical biopsy and/or clinical follow-up. RESULTS: Fifty-four (96%) bile duct biopsies were technically successful in terms of yielding a histological diagnosis. Thirty-one of the 56 (55%) biopsy specimens were positive for malignancy (27 adenocarcinoma, two islet cell-carcinoids, one small cell carcinoma, and one malignant lymphoma). Four (7%) were read by the pathologist as highly suspicious for malignancy, and 19 (34%) specimens were considered negative for malignancy. Sensitivity of atherectomy catheter endoluminal biliary biopsy in this study was 97% with a specificity of 100%. In addition, the positive predictive and negative predictive values of this modality were 100% and 93%, respectively. CONCLUSIONS: Endoluminal bile duct biopsy by Simpson atherectomy catheter appears to be a highly sensitive and specific method for establishing histological diagnosis of stenosing lesions in the biliary ductal system.

Adult↗

Prominence of symptoms and level of stigma among depressed patients in Calcutta.

A pilot study of 29 patients for research on clinical depression employed the framework of cultural epidemiology to examine illness-related experience, meaning, behaviour with a Bengali version of the explanatory Model Interview Catalogue (EMIC). This report examined patterns of distress and stigma with reference to the most troubling patient-specified symptom. All subjects were psychiatric outpatients in the Institute of Psychiatry, Calcutta, and met Diagnostic and Statistical Manual (DSM)-IV criteria for a major depressive episode. Only 5 patients (17.2%) identified sadness as the most troubling problem, and 48.3% specified pains and other somatic symptoms instead. An internally consistent stigma scale with Cronbach's alpha of .67, comprised 13 items, was used to assess stigma. In addition to the scale score for each subject, the contribution of each item was reported and compared. A suggestive, though not significantly lower value of the stigma score for patients reporting somatic symptoms as most troubling, compared with sadness, was consistent with findings from prior studies showing a positive relationship between the magnitude of depression and stigma. These findings are discussed with reference to their impact on recognition and help seeking among patients, and recognition and management of depression by general practitioner. Culturally distinctive presentations and social contexts of depression and other mental illnesses should be addressed in professional training and public health communications.

Adult↗

Evaluation of fine needle aspiration and imprint cytology in the early diagnosis of breast lesions with histopathological correlation.

Fifty-one breast lumps were studied by fine needle aspiration cytology (FNAC) and scrape imprint cytology. Of the 51 cases, 28 were malignant and included infiltrating duct carcinoma (22), well differentiated adenocarcinoma (2), mucinous, papillary and lobular carcinoma (one each) and malignant lymphoma (one). Benign lesions were mastitis, fibroadenoma and fibrocystic disease. The diagnostic accuracy of FNAC was 90.2% and that of imprint 94.1% with no false negatives. Two imprint smears and one aspirate designated suspicious were proved to be benign. The combination of FNAC and imprint cytodiagnosis gave a diagnostic accuracy of 96% thus proving their value in the rapid diagnosis of breast lesions.

Biopsy, Needle↗

An evaluation of ductal carcinoma in-situ of breast and its correlation with the grade of associated invasive component.

Twenty-five cases of Ductal carcinoma in situ(DCIS), of breast with an associated invasive component were selected for this study. The aim was to identify the percentage of malignant cases having DCIS component, to analyse the distribution of DCIS according to architecture and cytonuclear grading and evaluate the correlation between grade of DCIS with that of associated invasive component. The DCIS component was classified according to traditional architectural classification and Van-Nuys cytonuclear classification. The grading of the invasive component was done according to Nottingham's modification of Bloom-Richardson system. Architecturally 72% of DCIS components were of pure form, 28% were of mixed pattern. According to cytonuclear grading 24% cases had grade-I, 28% grade-II and 48% grade-III DCIS. The invasive component showed 16% cases in grade-III. After correlating the grade of DCIS and invasive component 91% positive correlation was found in grade-III cases followed by 66.6% in grade-I and 57.1% in grade-II cases.

Breast Neoplasms↗

Ponderomotive optical lattice for Rydberg atoms.

We propose to use the ponderomotive energy of Rydberg electrons in standing-wave light fields to form an optical lattice for Rydberg atoms. Application of the Born-Oppenheimer approximation shows that, with readily achievable experimental parameters, atoms in any Rydberg state can be trapped. Realization of this scheme would extend the benefits of atom trapping to highly excited atoms.

Journal Article↗

1,2-bis(pyridine-2-carboxamido)benzenate(2-), (bpb)2-: a noninnocent ligand. Syntheses, structures, and mechanisms of formation of [(n-Bu)4N][FeIV2(mu-N)(bpb)2(X)2] (X = CN-, N3-) and the electronic structures of [MIII(bpbox1)(CN)2] (M = Co, Fe).

The well-known tetradentate ligand 1,2-bis(pyridine-2-carboxamido)benzenate(2-), (bpb)2-, and its 4,5-dichloro analogue, (bpc)2-, are shown to be "noninnocent" ligands in the sense that in coordination compounds they can exist in their radical one- and diamagnetic two-electron-oxidized forms (bpbox1)- and (bpbox2)0 (and (bpcox1)- and (bpcox2)0), respectively. Photolysis of high-spin [(n-Bu)4N][FeIII(bpb)(N3)2] and its (bpc)2- analogue in acetone solution at room temperature generates the diamagnetic dinuclear complex [(n-Bu)4N][FeIV2(mu-N)(bpb)2(N3)2] and its (bpc)2- analogue; the corresponding cyano complex [(n-Bu)4N][FeIV2(mu-N)(bpb)2(CN)2] has been prepared via N3- substitution by CN-. Photolysis in frozen acetonitrile solution produces a low-spin ferric species (S = 1/2) which presumably is [FeIII(bpbox2)(N)(N3)]-, as has been established by EPR and Mössbauer spectroscopy. The mononuclear complexes [(n-Bu)4N][FeIII(bpb)(CN2)] (low spin), [Et4N][CoIII(bpb)(CN)2] and Na[CoIII(bpc)-(CN)2].3CH3OH can be electrochemically or chemically one-electron-oxidized to give [FeIII(bpbox1)(CN)2]0 (S = 0), [CoIII(bpbox1)(CN)2]0 (S = 1/2), and [CoIII(bpcox1)(CN)2]0 (S = 1/2). All complexes have been characterized by UV-vis, EPR, and Mössbauer spectroscopy, and their electro- and magnetochemistries have been studied. The crystal structures of [(n-Bu)4N][FeIII(bpb)(N3)2].1/2C6H6CH3, Na[FeIII(bpb)(CN)2], Na[CoIII(bpc)(CN)2].3CH3OH, [(n-Bu)4N][FeIV2(mu-N)(bpb)2(CN)2], and [(n-Bu)4N][FeIV2(mu-N)(bpb)(N3)2] have been determined by single-crystal X-ray diffraction.

Journal Article↗