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Biomedical subjects

A Mitra

Publications and source records attributed to A Mitra.

At least 19 recordsLinked to original sources
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↗
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↗
PubMed1995

Isolated avulsion of the flexor digitorum superficialis tendon.

Isolated, closed avulsion of the flexor digitorum superficialis tendon at its insertion is thought to be a rare diagnostic entity, with only six cases reported in the literature. However, we have diagnosed and treated 11 such cases, each presenting with a tender palmar mass and loss of active flexor digitorum superficialis function. Some patients had proximal interphalangeal joint contractures. Upon exploration, the retracted superficialis tendon was found to ensnare the profundus tendon at the level of the A1 pulley. Following tenolysis, flexor digitorum superficialis tendon excision, and in selected patients capsulotomies, each patient achieved good functional capacity.

Adult↗
PubMed1995

Structure and function of kidney water channels.

There is now firm evidence that water transporting proteins are expressed in renal and extrarenal tissues. In the kidney, proximal-type (CHIP28) and collecting duct (WCH-CD) water channels have been identified. We have cloned three kidney cDNAs with homology to the water channel (aquaporin) family, including a mercurial-insensitive water channel (MIWC), and a glycerol-transporting protein (GLIP) in collecting duct basolateral membrane. To elucidate water transporting mechanisms, a series of molecular and spectroscopic studies were carried out on purified CHIP28 protein and expressed chimeric and mutated CHIP28 cDNAs. The results indicate that CHIP28 transports water selectively, that CHIP28 monomers are assembled in membranes as tetramers, but that individual monomers function independently. Monomers contain multiple membrane-spanning helical domains. Based on these data and recent electron crystallography results, a model for water transport is proposed in which water moves through narrow pores located within individual CHIP28 monomers.

Amino Acid Sequence↗
PubMed1995

Peroneal nerve entrapment in athletes.

Peroneal nerve entrapment is one of the less common causes of exercise-induced leg pain in competitive athletes. This type of lower extremity peripheral nerve dysfunction is usually associated with activities that subject the nerve to constant compression or repetitive trauma. Herein, we present our experience with 12 competitive athletes treated for peroneal nerve entrapment. Diagnostic electromyography results, intraoperative findings, and the results of cadaveric dissections are discussed.

Athletic Injuries↗
PubMed1995

On-site adequacy assessments for image-directed fine needle aspirations: a study of 341 cases.

On-site adequacy assessments (OSAA) are reported to decrease the unsatisfactory and nondiagnostic rates of fine needle aspirations (FNAs). These have been routine in many institutions but were only recently introduced to our large teaching hospital. The results of FNAs performed in diagnostic radiology between January to December 1992 were compared to aspirations done by the same clinical staff during the first year (1993) after the addition of an on-site adequacy assessment service. In the year prior to OSAA, 154 FNAs were performed in diagnostic radiology and the material obtained was processed by a cytotechnologist. Of these, 89 (58%) cases were positive for malignant cells. Approximately half of these cases had confirmatory tissue biopsies processed in the surgical pathology department of our institution. The remaining 65 (42%) of cytology specimens were determined to be negative or nondiagnostic for malignancy. These canes either had no tissue follow-up or the tissue obtained was nondiagnostic. Before beginning OSAA, nine cases (6%) were interpreted as negative for malignancy, but subsequent tissue biopsies were malignant. There were no false positives during this time. Diagnostic sensitivity was 86% before OSAA. One hundred seventy-seven image directed FNAs were performed in the first year following the establishment of OSAA. Of these, 102 (58%) cases were interpreted as positive for malignant cells. About half of these patients went on to have confirmative tissue biopsies. Fifty-six (32%) cases were interpreted as negative for malignancy or nondiagnostic on FNA and follow-up tissue biopsies were also either negative or nondiagnostic. The false negative rate was 1% after OSAA and there were no false positives during this period. Diagnostic sensitivity was 98% after OSAA. In addition, the average overall number of passes per patient have decreased from 2.4 before OSAA to 1.6 after OSAA.

Biopsy, Needle↗
PubMed1994

A Chlorella virus gene promoter functions as a strong promoter both in plants and bacteria.

An upstream region from an algal virus methyltransferase gene was tested for promoter function in transgenic plants, electroporated monocot protoplasts and bacteria. Fusion of the 851 bp upstream region to a reporter gene significantly enhanced the reporter gene expression in transgenic Arabidopsis and potato plants and in electroporated maize and Sorghum cells relative to the cauliflower mosaic virus 35S promoter. The promoter was also functional in several Escherichia coli strains and in three species of phytopathogenic bacteria, Erwinia, Pseudomonas, and Xanthomonas. These findings indicate that the upstream region is a strong promoter uniquely functional in both eukaryotes and prokaryotes and capable of using both eukaryotic RNA polymerase II and bacterial RNA polymerases.

Arabidopsis↗