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S Mitra

Publications and source records attributed to S Mitra.

At least 37 records · Page 2Linked to original sources
PubMed2004

Rho kinase mediates cold-induced constriction of cutaneous arteries: role of alpha2C-adrenoceptor translocation.

Cold-induced vasoconstriction in cutaneous blood vessels is mediated in part by increased activity of vascular smooth muscle alpha2-adrenoceptors (VSM alpha2-ARs). In mouse cutaneous arteries, alpha2C-ARs are normally silent at 37 degrees C but mediate cold-induced augmentation of alpha2-AR responsiveness. In transfected HEK293 cells, this functional rescue is mediated by cold-induced translocation of alpha2C-ARs from the Golgi to the plasma membrane. Experiments were performed to determine the role of Rho/Rho kinase signaling in this process. Inhibition of Rho kinase (fasudil, Y27632 or H-1152) did not affect constriction of isolated mouse tail arteries to the alpha2-AR agonist UK 14 304 at 37 degrees C but dramatically reduced the augmented responses to the agonist at 28 degrees C. After Rho kinase inhibition, cooling no longer increased constriction evoked by alpha2-AR stimulation. Cooling (to 28 degrees C) activated Rho in VSM cells and increased the calcium sensitivity of constriction in alpha toxin-permeabilized arteries. Stimulation of alpha2-ARs in VSM cells had no effect on Rho activity or calcium sensitivity at 37 degrees C or 28 degrees C. In HEK293 cells transfected with alpha2C-ARs, cooling (to 28 degrees C) stimulated the translocation of alpha2C-ARs to the plasma membrane and this effect was prevented by inhibition of Rho kinase, using fasudil or RNA interference. Consistent with inhibition of the spatial rescue of alpha2C-ARs, fasudil inhibited alpha2-AR-mediated mobilization of calcium in tail arteries at 28 degrees C but not 37 degrees C. Therefore, cold-induced activation of Rho/Rho kinase can mediate cold-induced constriction in cutaneous arteries by enabling translocation of alpha2C-ARs to the plasma membrane and by increasing the calcium sensitivity of the contractile process.

Animals↗
PubMed2004

Anti-inflammatory activity of tea (Camellia sinensis) root extract.

Pharmacological studies were carried out with methanol-water (1:1) extract of dried tea (Camellia sinensis) root extract (TRE). TRE was found to possess anti-inflammatory, analgesic and antipyretic activities at 1/10th of its LD50 dose of 100 mg/kg i.p. It was found that TRE inhibited the arachidonic acid-induced paw oedema in rats which indicated that TRE produced the anti-inflammatory activity by inhibiting both the cyclooxygenase and lypooxygenase pathways of arachidonic acid metabolism. TRE also enhanced peritoneal cell count and the number of macrophages in normal mice. It is plausible that the saponins present in TRE may be responsible for these activities of TRE.

Animals↗
PubMed2004

Prevention of bone loss by oil extract of garlic (Allium sativum Linn.) in an ovariectomized rat model of osteoporosis.

The effects of oil extract of garlic (Allium sativum Linn.) on different primary and secondary osteoporotic marker changes were tested in an ovariectomized rat model of osteoporosis. Experiments were performed on three different rat models: sham-operated control, ovariectomized and ovariectomized supplemented with garlic oil. In ovariectomized group, there has been a significant increase in different relative organ weights compared to sham-operated control, while the uterine weight was found to be decreased. Supplementation with oil extract of garlic could effectively reverse these changes. Also low bone densities that developed in the ovariectomized group were significantly recovered in the garlic oil supplemented group. In our study, the development of high rate of bone turnover and osteoporosis in the ovariectomized animals were confirmed by significant alteration of serum alkaline phosphatase activity, serum tartrate resistant acid phosphatase activity, urinary excretion of calcium, phosphate, hydroxyproline and urinary calcium to creatinine ratio, when compared with the sham-operated control group. Garlic oil extract supplementation, apart from its unique influence in lowering blood cholesterol, could also prevent ovariectomy-induced rise in all the above-mentioned marker changes. The results of this study emphasize that oil extract of garlic possibly has a positive role in suppressing ovariectomy-induced bone resorption.

Alkaline Phosphatase↗
PubMed2004

Comparison of a digital and an analog signal processing system for neutron inelastic gamma-ray spectrometry.

We compared the value of using a digital signal processing unit for gamma-ray spectroscopy with that of an analog one for in situ measurements of gamma-rays generated by inelastic neutron scattering reactions with soil elements. A large cylindrical NaI(Tl) scintillation detector, 15.24 cm high by 15.24 cm diameter was used to measure carbon (C) and oxygen (O). The performance of the systems was assessed as a function of input count rate (ICR) by monitoring the peak areas of the C, 4.43 MeV, and O, 6.13 MeV, gamma-rays. In separate experiments, the digital and the analog systems were also compared using an intense 10.3 mCi 137Cs source to vary the ICR, and the 1.17 MeV peak area of 60Co was used as the reference.

Analog-Digital Conversion↗
PubMed2004

Pseudoaneurysm following lateral wall myocardial infarction.

Pseudoaneursym (PA) formation of left ventricle (LV) following acute myocardial infarction (AMI) is uncommon and is usually believed to be associated with a grave prognosis. We describe a case of 55 year old male patient presented with AMI and heart failure with a systolic murmur later diagnosed to have PA of the lateral wall of LV on echocardiography (transthoracic and transesophageal, TTE andTEE). Cardiac MRI and coronary angiogram (CAG) were performed. CAG showed 60% lesion at origin of major obtuse marginal artery (OM1). The patientwas advised surgical treatment, but he refused and took discharge against medical advice on 27th dayof admission on stable condition.

Aneurysm, False↗
PubMed2003

Sediment characteristics affecting desorption kinetics of select PAH and PCB congeners for seven laboratory spiked sediments.

Measures of desorption are currently considered important as potential surrogates for bioaccumulation as measures of the bioavailability of sediment-sorbed contaminants. This study determined desorption rates of four laboratory spiked compounds, benzo[a]pyrene (BaP), 2,4,5,2',4',5'-hexachlorobiphenyl (HCBP), 3,4,3',4'-tetrachlorobiphenyl (TCBP), and pyrene (PY), to evaluate the effect of sediment characteristics. The compounds were sorbed onto seven sediments with a broad range of characteristics. Desorption was measured by Tenax-TA extraction from aqueous sediment suspensions. Desorption rates were modeled using an empirical three compartment model describing operationally defined rapid, slow, and very slow compartments. The sediments were characterized for plant pigments, organic carbon (OC), total nitrogen (TN), lipids, NaOH extractable residue, lignin, amino acids, soot carbon, and particle size fractions. Desorption from the rapid compartment for each of the planar compounds BaP, PY, and TCBP was significantly correlated to sediment characteristics that could be considered to represent younger (i.e., less diagenetically altered) organic matter, e.g., plant pigment, lipid, and lignin contents. However, for these compounds there were no significant correlations between desorption and OC, TN, soot carbon, or amino acid contents. HCBP desorption was different from the three planar molecules. For HCBP, the flux from the rapid compartment was negatively correlated (0.1 > p > 0.05) with the OC content of the sediment. Overall, HCBP desorption was dominated by the amount of OC and the particle size distribution of the sediments, while desorption of the planar compounds was dominated more by the compositional aspects of the organic matter.

Adsorption↗
PubMed2003

Retinopathy of prematurity in VLBW and extreme LBW babies.

OBJECTIVE: This is a hospital-based, prospective clinical study to determine the incidence, risk factors, and outcome of extreme low birth weight and very low birth weight pre-term babies with retinopathy of prematurity (ROP) at the Sultan Qaboos University Hospital, Oman. METHODS: All babies with a birth weight =/< 1500 g and gestational age =/< 32 weeks admitted in the Neonatal Unit, were screened for ROP between 4 to 6 weeks of age and staged according to the international classification and were followed up until complete vascularization of the retina. Fifty nine babies formed the study group. RESULTS: The overall incidence of ROP was 25.4% (15 out of 59), of which 6 babies had severe ROP and underwent cryotherapy/laser. All babies with ROP had a birth weight < 1250 g and were born before 31 weeks of gestation. CONCLUSION: ROP is a multifactorial disease, the immature retina of the pre-term baby being the primary factor. Incidence and severity was inversely proportional to birth weight and gestational age. Multiple logistic regression analysis showed that sepsis and total parenteral nutrition to be highly significant risk factors. Repeated blood transfusions, hypotension and congenital heart disease with left to right shunt were seen to be considerably associated with the development of ROP. A decrease in overall incidence and severity of ROP was observed in this study.

Blood Transfusion↗
PubMed2003

Haplotype structure of TP53 locus in Indian population and possible association with head and neck cancer.

It has been proposed that a constellation of three TP53 polymorphisms (intron 3 16 bp duplication, codon 72 BstUI, and intron 6 Nci I RFLP at nt 13494) constitute a haplotype predictive of increased cancer risk. We have estimated the allele frequency of these polymorphisms in three endogamous Indian ethnic populations from three different geographic locations (viz. Iyer from south India, Brahmin from central India and Mahishya from eastern India), as well as in head and neck squamous cell carcinoma (HNSCC) patients, and in ethnically matched normal individuals from the eastern region of India. The genotype distributions and allele frequencies of the three polymorphisms in all but one population, as well as in patients, showed a good fit to Hardy-Weinberg equilibrium. Strong linkage disequilibria were observed between all loci in every population examined, except for the 16bp-Nci I haplotype in the Mahishya population. The Mahishya population differed significantly from the other two populations with respect to differences in allele frequency and haplotype frequency. Although there were no significant differences in genotypic frequency at any of the loci between HNSCC patients and the matched control population, the minor allele frequency of codon 72 and intron 3 16 bp polymorphisms showed significant variation. Variation in overall haplotype frequency between patients and normal individuals was significant (p = 0.036) when two rare haplotypes 2-1-2 and 1-2-1 were combined. The rare haplotype 2-1-2 was found to be modestly over represented in HNSCC patients as compared to normal individuals.

DNA↗
PubMed2003

Comparison of temperament and character profiles of anesthesiologists and surgeons: a preliminary study.

BACKGROUND: Given the high levels of stress in anesthesiologists and also their close working liaison with surgeons, it may be worthwhile to compare the personality profiles of these two groups of professionals. AIM: To compare the personality profiles of surgeons and anesthesiologists, using a well-standardized and validated instrument. SETTINGS AND DESIGN: Survey (cross-sectional) on surgeons and anesthesiologists working in several medical institutes in India. MATERIAL & METHODS: The self-report Temperament and Character Inventory, 125-item version (TCI-125) was mailed out to an incidental sample of surgeons and anesthesiologists working in medical institutes in India. Of the 200 questionnaires sent (100 to anesthesiologists and surgeons each), 93 completed responses were returned (46 anesthesiologists, 47 surgeons; return rate 46.5%). STATISTICAL ANALYSIS: Student's unpaired 't' test; P<0.05 was considered statistically significant. RESULTS: The mean scores of anesthesiologists vis-a-vis surgeons on the various temperament dimensions were Novelty seeking: 8.6 vs. 9.2; Harm avoidance: 7.3 vs. 8.1; Reward dependence: 8.1 vs. 8.0; and Persistence: 3.0 vs. 3.1, respectively. Similar scores for the character dimensions were Self-directedness: 16.9 vs. 15.9; Cooperativeness: 17.5 vs. 16.5; and Self-transcendence: 7.0 vs. 6.7, respectively. There was no significant difference between the surgeons and anesthesiologists on any of the temperament and character variables of personality chosen for the study. CONCLUSION: Personality measures did not differ significantly between surgeons and anesthesiologists in this preliminary investigation. If replicated on a larger and more representative sample, the findings have clinical relevance to improve the working relationship between these two groups of closely working professionals.

Adult↗
PubMed2002

Rotational dynamics of propane in Na-Y zeolite: a molecular dynamics and quasielastic neutron-scattering study.

We report results from molecular dynamics (MD) simulations and quasielastic neutron-scattering (QENS) measurements on the rotational dynamics of propane in Na-Y zeolite at room temperature with a loading of four molecules per alpha cage. Rotational part of the intermediate scattering function F(Q,t) obtained from the MD simulation suggests that rotational motion is faster relative to the translational motion. Various rotational models fitted to the MD data suggest that rotation is isotropic. It is found that the hydrogen atoms lie, on the average, on a sphere of radius 1.88+/-0.05 A, which is also the average distance of the hydrogen atoms from the center of mass of the propane molecule. Results from QENS measurements are in excellent agreement with those obtained from MD, suggesting that the intermolecular potential employed in the MD simulation provides a realistic description of propane motion within faujasite. The rotational diffusion constant D(R) is 1.05+/-0.09 x 10(12) sec(-1) from the QENS data, which may be compared with that obtained from the MD data (0.82+/-0.05 x 10(12) sec(-1)).

Journal Article↗
PubMed2002

Trends in long-term management of survivors of acute myocardial infarction by cardiologists in a government university-affiliated teaching hospital.

BACKGROUND: Despite prospective randomized control trials showing that beta blockers, aspirin, angiotensin-converting enzyme (ACE) inhibitors, and lipid-lowering agents improve survival rates after myocardial infarction (MI), these agents are routinely underutilized. HYPOTHESIS: Our aim was to determine the frequency with which cardiologists at a government, university-affiliated teaching hospital prescribe aspirin, beta blockers, ACE inhibitors, calcium-channel blocking agents (CCBs), and lipid-lowering agents in patients post MI. The patients were followed by their primary care physicians in this hospital after discharge. We evaluated changes in patients' medical management at an average of 24 months after discharge from the acute event. METHODS: Clinical data relative to long-term use of life-saving drugs in 156 survivors of definite MI (WHO criteria) at a government, university-affiliated teaching hospital were analyzed over a 24-month follow-up period. RESULTS: Over 90% of patients with acute MI were given aspirin and beta blockers at discharge. About 50% of these patients were given ACE inhibitors, only 25% were prescribed CCBs, and 21% were given lipid-lowering agents. At 24 months of follow-up, the percentage of patients receiving aspirin, beta blockers, and ACE inhibitors had fallen to 88% (p = 0.0408), 71% (p < 0.0001), and 43% (p = 0.1122), respectively, whereas use of lipid-lowering agents slightly increased (p = 0.4277). Use of CCBs had also fallen (p = 0.0001). Nonetheless, the use of aspirin, beta blockers, and ACE inhibitors was higher than that in the National Registry of similar patients at discharge (p < 0.0001). CONCLUSIONS: Patients at a government, university-affiliated teaching hospital are likely to receive life-saving therapy at discharge, in accordance with the American College of Cardiology/American Heart Association (ACC/AHA) guidelines. There is a modest decrease in intake of these life-saving drugs during the follow-up period. As documented earlier, cardiologists in a teaching institution are more likely to prescribe established life-saving drugs than do primary care physicians. However, full-time primary care physicians at a university-affiliated teaching hospital continue to use these therapies at a higher rate than do those outside academic medicine.

Adrenergic beta-Antagonists↗
PubMed2002

Effect of alkalinization and/or hyaluronidase adjuvancy on a local anesthetic mixture for sub-Tenon's ophthalmic block.

BACKGROUND AND OBJECTIVES: pH adjustment and/or addition of hyaluronidase to local anesthetic drugs decrease the time to onset and prolong the duration of regional anesthetic techniques for ocular surgery. The objective of this study was to investigate whether these factors are effective also in sub-Tenon's block. METHODS: Sixty patients were randomly assigned to four groups in a double blind, prospective fashion, and received 5.125 ml mixtures as follows: 2.5 ml lignocaine 2%, 2.5 ml bupivacaine 0.5% and 0.125 ml isotonic saline (group LB); 2.5 ml lignocaine 2%, 2.5 ml bupivacaine 0.5%, 15 IU hyaluronidase/ml and 0.125 ml isotonic saline (group LBH); 2.5 ml lignocaine 2%, 2.5 ml bupivacaine 0.5% and 0.125 ml sodium bicarbonate 8.4% (group LBpH); and 2.5 ml lignocaine 2%, 2.5 ml bupivacaine 0.5%, 15 IU hyaluronidase/ml and 0.125 ml sodium bicarbonate 8.4% (group LBHpH). This measurement was based on one quadrant sub-Tenon's block. Akinesia was assessed every 30 s. RESULTS: No statistically significant differences were found between the groups regarding mean times to onset and to complete akinesia. Group LBH displayed a significantly lower frequency of patients experiencing pain and a lower need for rescue medication during surgery than the other groups. CONCLUSION: pH adjustment and/or addition of hyaluronidase to a mixture of lignocaine and bupivacaine did not shorten the time to onset of akinesia following sub-Tenon's technique. However, the addition of hyaluronidase was associated with a lower fraction of patients experiencing pain during surgery.

Adjuvants, Anesthesia↗
PubMed2002

Antineoplastic effect of new boron compounds against leukemic cell lines and cells from leukemic patients.

Three new boron compounds, dihydroxy (oxybiguanido) boron (iii) hydrochloride monohydrate (HB), guanidine biboric acid adduct (GB) and hydroxosalicyl hydroxomato boron (iii) (SHB) were studied to observe their antineoplastic effect, if any. Leukemic cells isolated from acute lymphatic leukaemia (ALL) patients and chronic myeloid leukaemia patients (CML) and myeloid leukemia cell lines (HL 60 and U-937) showed cell growth inhibition after treatment with the boron compounds. MTT assay showed that the growth of metabolically active cells was inhibited by treatment with these drugs. The molecular mechanism by which SHB induced apoptosis in immature blast cells was also investigated by ladder formation in gel electrophoresis.

Acute Disease↗