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Biomedical subjects

A Mitra

Publications and source records attributed to A Mitra.

At least 55 records · Page 3Linked to original sources
PubMed2000

Evaluation of groundwater pollution potential of sewage-irrigated vegetable growing areas of the eastern fringe of Calcutta city.

In recent years recycling in agriculture is a common method of disposal or utilisation of waste. However, recycling of wastes may cause contamination of groundwater by toxic elements like heavy metals, cationic and anionic contaminants and pathogens. Groundwater of shallow and deep tubewells was collected during 1991 to 1997 from raw sewage effluent irrigated garbage farming areas on the eastern fringe of Calcutta city. In general raw sewage effluents, sludges and sewage-irrigated soils contain very high amounts of cations, anions, organics and heavy metals. It is found that most of the groundwater contained undesirable pH, total dissolved solids, total hardness, calcium, magnesium, phenolic compounds, iron and manganese and the observed values or concentrations were much above the maximum desirable limits specified by World Health Organisation (WHO) and Bureau of Indian Standards (BIS) for use as drinking water. Groundwater of that area may be used for irrigation. Dispersion by leaching of the metals, cationic and anionic contaminants from irrigated soil and from settled bottom sludge in unlined sewage channels are the principal causes of groundwater contamination. Some management plans have been suggested to control further deterioration of groundwater quality.

Agriculture↗
PubMed1999

4-hydroxycinnamoyl-CoA hydratase/lyase (HCHL)--An enzyme of phenylpropanoid chain cleavage from Pseudomonas.

The enzyme 4-hydroxycinnamoyl-CoA hydratase/lyase (HCHL), which catalyzes a hydration and two-carbon cleavage step in the degradation of 4-hydroxycinnamic acids, has been purified and characterized from Pseudomonas fluorescens strain AN103. The enzyme is a homodimer and is active with three closely related substrates, 4-coumaroyl-CoA, caffeoyl-CoA, and feruloyl-CoA (Km values: 5.2, 1.6, and 2.4 microM, respectively), but not with cinnamoyl-CoA or with sinapinoyl-CoA. The abundance of the enzyme reflects a low catalytic center activity (2.3 molecules s-1 at 30 degrees C; 4-coumaroyl-CoA as substrate).

Acyl Coenzyme A↗
PubMed1999

Gunshot wounds to the hand: management and economic impact.

Low-velocity firearms represent the majority of civilian gunshot wounds to the hand, yet much of the literature is based on high-velocity injuries. The authors reviewed their treatment regimen for civilian gunshot wounds to the hand and offer a treatment algorithm that emphasizes early debridement and fracture stabilization. They also address the economic impact on society. The authors reviewed 121 fractures in 90 patients with gunshot wounds to the hand treated at an urban trauma center during the last 5 years. All patients were managed with irrigation and debridement, elevation, intravenous antibiotics, and early fracture stabilization. Sixty fractures were managed with rigid internal or external fixation: Kirshner wires (26%), miniplates (16%), and external fixation (8%). Fifty-six fractures were managed with closed reduction. Five fractures required amputation. There was one subsequent infection and two late amputations. The cost of hospitalization and operative care was more than $1.7 million. For gunshot wounds to the hand the authors advocate immediate irrigation and debridement, intravenous antibiotics, early fracture stabilization, and a low threshold for internal fixation. This regimen is supported by their low infection and complication rates.

Algorithms↗
PubMed1998

Kappa-casein polymorphisms in Indian dairy cattle and buffalo: a new genetic variant in buffalo.

We screened 57 Sahiwal cattle (Bos indicus) and 53 Murrah, 19 Nili-Ravi and 11 Egyptian buffaloes (Bubalus bubalis) to detect the polymorphisms at kappa-casein (CSN3) gene using the polymerase chain reaction (PCR). CSN3 A and B alleles were identified by PCR-RFLP using the restriction enzymes that detect the underlying nucleotide changes at codon 136 (Taql) and at codon 148 (HindIII or HinfI) in cattle. The frequency of CSN3 B allele in the Sahiwal cattle was estimated as 0.16 with no homozygous BB animal. Using the same set of primers as used in the Sahiwal cattle, a part of exon IV of buffalo CSN3 gene was amplified, but restriction enzyme analysis using HindIII/HinfI and TaqI did not reveal any polymorphism. However, DNA sequencing of the amplified fragment (GenBank Acc. No. U96662) revealed one polymorphism at codon 135 (ThrACC -->I1eATC) in buffalo; the frequencies of 135 Thr/Ile alleles were estimated as 0.88 and 0.12, respectively.

Alleles↗
PubMed1998

T cells and T-cell cytokine transcripts in the synovial membrane in patients with osteoarthritis.

The synovial membrane in osteoarthritis (OA) often exhibits inflammatory infiltrates, but the role of T cells in these infiltrates is not known. T-cell activation antigens were analyzed by immunohistochemistry, and T-cell cytokine transcripts were measured by competitive PCR in synovial membranes from patients with OA and rheumatoid arthritis (RA). Lymphoid cell aggregates, containing primarily CD3+ T lymphocytes, were found in 65% of patients with OA. Mononuclear cells expressing the activation antigens CD69, CD25, CD38, CD43, CD45RO, and HLA class II were present in both patient groups, although in higher numbers in patients with RA. Interleukin 2 (IL-2) transcripts were found in 10 of 18 patients with OA versus 12 of 13 patients with RA (P = 0.03). Gamma interferon (IFN-gamma) transcripts were detected in 9 of 18 patients with OA versus 10 of 13 patients with RA (not significant), whereas IL-10 transcripts were found in nearly all patients. IL-4 and IL-5 were not detected in any patients. The levels of IFN-gamma and IL-2 transcripts, normalized for T-cell number equivalents, were not statistically different between OA and RA, but the levels of IFN-gamma, normalized for total cell number equivalents, were lower in OA than in RA (P = 0.01). Synovial membranes that expressed IL-2 and IFN-gamma transcripts were more likely to have heavier infiltrations of T cells and cells bearing activation markers than synovial membranes that did not express these cytokines. The presence of activated T cells and TH1 cytokine transcripts in chronic joint lesions of patients with OA suggests that T cells contribute to chronic inflammation in a large proportion of these patients.

Aged↗
PubMed1998

Effect of inhaled surfactant on pulmonary deposition and clearance of technetium-99m-DTPA radioaerosol.

UNLABELLED: To establish the effect of an aerosolized synthetic surfactant (Exosurf) on pulmonary 99mTc-diethylenetriamine pentaacetic acid (DTPA) aerosol deposition and clearance, radioaerosol studies were performed at varying times and under varying conditions after surfactant inhalation in canine lungs. METHODS: Twenty-three dogs had a baseline 99mTc-DTPA study; 2 days later the study was repeated after inhalation of a 1.5-ml/kg dose of Exosurf aerosolized by an ultrasonic nebulizer. The clearance half-time (T1/2) of 99mTc-DTPA from each lung was measured at different times (from 10 min to 3 hr) after Exosurf inhalation. For comparison, five animals had a 99mTc-DTPA study 10 min after inhalation of the same dose of saline as Exosurf. An additional five animals inhaled a 99mTc-DTPA-Exosurf mixture to investigate the distribution of Exosurf. RESULTS: Technetium-99m-DTPA distributed uniformly without significant changes in penetration indexes before and after inhalation of Exosurf and the 99mTc-DTPA-Exosurf mixture. After Exosurf inhalation, 99mTc-DTPA clearance at 10 min (T1/2; 35.6 +/- 8.7 min; n = 6) and 40 min (29.4 +/- 6.3 min; n = 4) was significantly prolonged compared with the matched baseline values (24.7 +/- 6.4 min, p < 0.0001; and 21.7 +/- 8.9 min, p = 0.01, respectively). However, later clearance times were not prolonged. By contrast, after saline inhalation, 99mTc-DTPA distributed inhomogeneously, and clearance times T1/2) were not altered from the matched baseline values. CONCLUSION: Aerosolized Exosurf distributes homogeneously in the lungs. Exosurf initially retards 99mTc-DTPA aerosol clearance, but 99mTc-DTPA transalveolar clearance returns to baseline rates within 1-2 hr. Technetium-99m-DTPA aerosol clearance measurements can be used to monitor the effect of inhaled Exosurf on pulmonary epithelial integrity.

Administration, Inhalation↗
PubMed1998

Spectrophotometric and spectrofluorometric studies on interaction of cationic dyes with bacterial capsular polysaccharide.

Interaction of Klebsiella K14 capsular polysaccharide with cationic dyes pinacyanol chloride, acridine orange and phenosafranin has been studied by spectrophotometric and spectrofluorometric techniques. The polymer containing both glucuronic acid and pyruvic acid in its repeating unit behaved as a unique polyelectrolyte. It induced blue shift of the absorption band of pinacyanol chloride indicating strong metachromasy. Stoichiometry of the polyanion and the dye cations in the polymer-dye compound (1:2) indicated that both glucuronic acid and pyruvic acid acted as potential anionic sites for interaction with the cationic dye molecules. The stoichiometry of anionic site (of polyanion): cationic site (of dye) in the polymer dye compound was calculated as 1:1. Interaction of the polymer with acridine orange and phenosafranin dyes studied by fluorescence measurements demonstrated Stern-Volmer type of quenching. Equivalent weight of the polymer was determined by spectrophotometric and spectrofluorometric titrations. From the present studies chromotropic property of the polymer was established.

Acridine Orange↗
PubMed1997

Inactivation of rotavirus by new polymeric water disinfectants.

Two new insoluble polymeric materials were evaluated for their efficacies in inactivating rotavirus in flowing water in a biocidal filter application. The two polymers are N-chloro and N-bromo derivatives of a poly-styrene hydantoin prepared from commercial poly-styrene. The studies were conducted for rotavirus in halogen demand-free water at pH 7.0, 25 degrees C and Environmental Protection Agency (EPA) Test Water no. 2 at pH 9.0, 4 degrees C which contained heavy halogen demand. The range of flow rates studied was 0.16-1.22 ml s-1 corresponding to contact times in the range of 4-24 s. Both of the polymers were effective in inactivating rotavirus, the N-bromo derivative providing a 4-6 log reduction under the test conditions. The materials may be useful as supplemental filters for hand-held water purification units.

Disinfectants↗
PubMed1997

Perceptions and misconceptions of the plastic and reconstructive surgeon.

Little is known about professional perceptions of plastic and reconstructive surgery. In an era of managed health care and social reform, public perception, or misconception, may ultimately have a significant impact on this specialty. A survey was conducted to provide some initial evidence for the scope and scale of the misconceptions. Three populations were surveyed for this study: consecutive patients visiting a primary-care facility, medical students, and primary-care physicians. The survey addressed various aspects of plastic surgery-reconstruction, hand, craniofacial, and aesthetic surgery. One thousand one hundred twenty-one individuals of various ages, education levels, and ethnic backgrounds participated in this study. Our data demonstrate that public perception of the plastic and reconstructive surgeon is limited and grossly underestimates this specialty. Although the plastic surgeon is associated with reconstructive surgery, they are not necessarily identified as primary surgeons for procedures fundamental to this specialty. Furthermore, a significant number of respondents would prefer a cosmetic surgeon for aesthetic procedures. We believe that it is crucial that the public, physicians, and medical establishments (e.g., insurance companies, hospital administrations) be educated on the essence of plastic and reconstructive surgery.

Adult↗
PubMed1997

Thromboxane-mediated alveolar responses to acute obstruction of the pulmonary vasculature.

To investigate the mechanisms responsible for the accelerated radioaerosol transalveolar clearance rates caused by acute balloon occlusion of the pulmonary arterial tree in dogs, the effects of vagal tone (n = 5) and prostaglandins (n = 21) including thromboxane were evaluated. In 15 animals, serial pulmonary arterial and aortic blood samples were acquired to evaluate pertinent metabolic products. Balloon occlusion of a localized arterial territory caused significant acceleration of technetium-99m diethylenetriamine pentaacetic acid (Tc-99m DTPA) clearance in the zone immediately distal to the occlusion (baseline clearance half-time 23.1 +/- 0/7 min versus 19.3 +/- 0.4 min, mean +/- SEM, p < 0.05). Vagotomy had no effect on occlusion-accelerated clearance. However, significant (p < 0.05) normalization did occur in the presence of indomethacin (21.9 +/- 0.4 min) and meclofenamic acid (20.4 +/- 0.5 min). Plasma values of thromboxane rose dramatically (pulmonary blood baseline 119 pg/ml to > 40,000 pg/ml) and transiently immediately after pulmonary vascular occlusion, and this rise was blunted significantly (peak pulmonary thromboxane B2 [TXB2] concentration = 668 pg/ml, p < 0.05) by meclofenamic acid. Significant normalization of local DTPA clearance rates also occurred in the presence of a thromboxane receptor blocker (n = 4), even when blood levels of thromboxane were elevated. Changes in transalveolar DTPA clearance rates after balloon occlusion of pulmonary arteries seem to a significant extent to be thromboxane-mediated.

Animals↗
PubMed1996

A mammalian 2-5A system functions as an antiviral pathway in transgenic plants.

Resistance to virus infections in higher vertebrates is mediated in part through catalysis of RNA decay by the, interferon-regulated 2-5A system. A functional 2-5A system requires two enzymes, a 2-5A synthetase that produces 5'-phosphorylated, 2',5'-linked oligoadenylates (2-5A) in response to double-stranded RNA, and the 2-5A-dependent RNase L. We have coexpressed these human enzymes in transgenic tobacco plants by using a single plasmid containing the cDNAs for both human RNase L and a low molecular weight form of human 2-5A synthetase under control of different, constitutive promoters. Expression of the human cDNAs in the transgenic plants was demonstrated from Northern blots, by specific enzyme assays, and by immunodetection (for RNase L). Infection of leaves, detached or in planta, of the coexpressing transgenic plants by tobacco mosaic virus, alfalfa [correction of alfafa] mosaic virus, or tobacco etch virus resulted in necrotic lesions. In contrast, leaves expressing 2-5A synthetase or RNase L alone and leaves containing the plasmid vector alone produced typical systemic infections. While alfalfa mosaic virus produced lesions only in the inoculated leaves regardless of the concentration of virus in the inoculum, high, but not low, levels of tobacco etch virus inoculum resulted in escape of virus to uninoculated leaves. Nevertheless, there was a substantial reduction of tobacco etch virus yield as measured by ELISA assay in the coexpressing transgenic plants. These results indicate that expression of a mammalian 2-5A system in plants provides resistance to virus infections.

Adenine Nucleotides↗
PubMed1996

Porcine gastroepiploic artery as an in vitro experimental model to study vasodilators in microsurgery.

Arterial vasospasm is a common problem in microsurgery. This pharmacological study compares seven vasodilators-lidocaine, papaverine, nicardipine, verapamil, diltiazem, sodium nitroprusside, and hydralazine-for their efficacy and potency in an experimental model of vasospasm. Porcine gastroepiploic arteries were cut into rings to measure isometric tension development in vitro. The arteries were preconstricted with endothelin-1, a stable thromboxane A2 analogue, norepinephrine, or potassium, and then exposed to increasing concentrations of each vasodilator. Every vasodilator except hydralazine and sodium nitroprusside was efficacious in producing near-maximal relaxation of arteries preconstricted with any vasospastic substance. The five efficacious vasodilators differed markedly in potency, as reflected in the concentrations producing half-maximal relaxation. The order of potency was nicardipine < or = verapamil or diltiazem < papaverine < lidocaine. This study suggests that nicardipine would be the most potent vasodilator for systemic or direct intra-arterial administration. Papaverine and lidocaine, in concentrations employed clinically, were both efficacious as topical vasodilators.

Animals↗
PubMed1996

Water transport across mammalian cell membranes.

This review summarizes recent progress in water-transporting mechanisms across cell membranes. Modern biophysical concepts of water transport and new measurement strategies are evaluated. A family of water-transporting proteins (water channels, aquaporins) has been identified, consisting of small hydrophobic proteins expressed widely in epithelial and nonepithelial tissues. The functional properties, genetics, and cellular distributions of these proteins are summarized. The majority of molecular-level information about water-transporting mechanisms comes from studies on CHIP28, a 28-kDa glycoprotein that forms tetramers in membranes; each monomer contains six putative helical domains surrounding a central aqueous pathway and functions independently as a water-selective channel. Only mutations in the vasopressin-sensitive water channel have been shown to cause human disease (non-X-linked congenital nephrogenic diabetes insipidus); the physiological significance of other water channels remains unproven. One mercurial-insensitive water channel has been identified, which has the unique feature of multiple overlapping transcriptional units. Systems for expression of water channel proteins are described, including Xenopus oocytes, mammalian and insect cells, and bacteria. Further work should be directed at elucidation of the role of water channels in normal physiology and disease, molecular analysis of regulatory mechanisms, and water channel structure determination at atomic resolution.

Amino Acid Sequence↗
PubMed1996

Clinical profile of stroke in relation to glycaemic status of patients.

Present study was undertaken in fifty consecutive patients of acute stroke to assess the role of glycemic status on clinical profile of stroke. Majority of patients (76%) were in age group of 41-70 years. The patients were classified into four groups: euglycemics (33), known diabetics (8), newly diagnosed diabetics (6) and stress hyperglycemics (3). Diabetics as well as stress hyperglycemics had higher prevalence of larger sized severe haemorrhagic stroke with poor outcome and there was positive correlation between them.

Acute Disease↗
PubMed1996

Complications of treadmill testing.

Complications occurring in 2,400 treadmill tests are reported, out of which 2107 (87.8%) were on males and 292 (12.2%) on females. The total number of patients with complications was 29 (1.2%) and the types were: acute MI in 2, ventricular tachycardia (sustained) in 3, nonsustained in 7 with ventricular couplets in 3 patients, atrial tachyarrhythmias in four of AVNRT in 2, EAT in 2, SVT with abberancy in 1, SVT (undifferentiated) in 3, bradyarrhythmias in form of sinus bradycardia in 4, hypotension in 4 and AV block in 2. There were no deaths. Only 8 (0.33%) patients required treatment-2 each of acute MI, sustained VT, AVNRT and hypotension, though only 4 of them were hospitalised (2 each of acute MI and VT) and subsequently discharged. Highest incidence of complications was seen in post MI patients (2.01%) followed by those with typical anginal pain (1.9%) and they had more serious problems in form of MI and sustained VT. 55.17% patients with complications were positive for provocative ischaemia as compared to 22.75% positivity in the total. Although 14 (38.2%) patients developed complications at workload of 4-6 METS but 2 achieved load of 10 METS also. Complications were seen mostly during exercise and also during recovery only.

Arrhythmias, Cardiac↗