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Biomedical subjects

R Dutta

Publications and source records attributed to R Dutta.

At least 19 recordsLinked to original sources
PubMed2006

Prevalence of Chlamydia trachomatis and bacterial vaginosis in women presenting to the early pregnancy unit.

A total of 674 women attending the early pregnancy unit during the study period were offered screening with high vaginal and endocervical swabs and 516 agreed to participate in the study. The overall prevalence of chlamydia was 1.96% (95% CI 0.9-3.6). Some 10.5% were under the age of 25 years and the prevalence in this group was 1.85% (95% CI 0.05-9.9). The overall prevalence of bacterial vaginosis was 3.5% (95% CI 2.2-5.5). The prevalence of common genital infections is low in a population of women presenting to the early pregnancy unit. This is of relevance to women having surgical evacuation for miscarriage and randomised trials should be undertaken to evaluate the role of prophylactic antibiotics for such cases.

Adult↗
PubMed2004

Clinical evaluation of the electronic nose in the diagnosis of ear, nose and throat infection: a preliminary study.

The term electronic nose describes an electronic system that is able to mimic the human sense of smell. Electronic noses have been developed over the last 10 or more years to perform a variety of identification tasks in various industries. More recently electronic noses have attracted new interest in their application in the field of medical diagnosis. The aim of this study is to explore the use of an electronic nose to identify and classify pathogens associated with ear, nose and throat (ENT) infections. In this study 90 bacterial swab samples were collected from 90 patients with ENT infections. Some of these samples were analysed immediately with a commercial electronic nose (Cyranose C320). Similar numbers of swabs were also taken from the same site of infection and were sent for microbiology culture and sensitivity. The electronic nose diagnosis was compared with the microbiology diagnosis and it was found that the electronic nose diagnosis was correct in 88.2 per cent of the cases, which is an encouraging result.

Bacterial Infections↗
PubMed2001

Genetic variation at minisatellite loci D1S7, D4S139, D5S110 and D17S79 among three population groups of eastern India.

Genetic variation at four minisatellite loci D1S7, D4S139, D5S110 and D17S79 in three predominant population groups of eastern India, namely Brahmin, Kayastha and Garo, are reported in this study. The Brahmin and Kayastha are of Indo-Caucasoid origin while the Garo community represents the Indo-Mongoloid ethnic group. The methodology employed comprised generation of HaeIII-restricted fragments of isolated DNA, Southern blotting, and hybridization using chemiluminescent probes MS1, pH30, LH1 and V1 for the four loci. All four loci were highly polymorphic in the population groups. Heterozygosity values for the four loci ranged between 0.68 and 0.95. Neither departure from Hardy Weinberg expectations nor evidence of any association across alleles among the selected loci was observed. The gene differentiation value among the loci is moderate (GST = 0.027). A neighbour-joining tree constructed on the basis of the generated data shows very low genetic distance between the Brahmin and Kayastha communities in relation to the Garo. Our results based on genetic distance analysis are consistent with results of earlier studies based on serological markers and linguistic as well as morphological affiliations of these populations and their Indo-Caucasoid and Indo-Mongoloid origin. The minisatellite loci studied here were found to be not only useful in showing significant genetic variation between the populations but also to be suitable for human identity testing among eastern Indian populations.

Asian People↗
PubMed2001

Nux vomica 30 prepared with and without succession shows antialcoholic effect on toads and distinctive molecular association.

Adult toads, Bufo melanostictus, were administered Nux vomica (Nux v) 30 prepared with and without succussion on the tongue. The drug was mixed with sterile distilled water at the rate 0.05ml/ml water and given orally 0.05ml/individual. The control consisted of blank ethanol solution. Seeds of Strychnos nuxvomica were ground and extracted with 90% ethanol in the laboratory. Nux v 30 was prepared by successive dilution and succussion in 30 steps, Nux v 30 u was prepared by successive dilution only. Four hours after treatment, toads were given 25% ethanol i.p. at 8g/kg body weight. The duration of ethanol induced sleep time was recorded for each toad. Both Nux v 30 and Nux v 30 u significantly reduced ethanol induced sleep time in toads as compared to their respective controls. Electronic, infra red and nuclear magnetic resonance spectra of Nux v 30, Nux v 30 u and their diluent medium (90% ethanol) show marked differences from each other. These dilutions and ethanol 30 and ethanol 30 u show marked differences from each other with respect to spin-lattice relaxation time (T1) and chemical shift. The difference has been attributed to the variation in intra and inter-molecular association of ethanol and water.

Administration, Oral↗
PubMed2001

Detection of species of graft in xenotransplants using arbitrary primed polymerase chain reaction.

Because of a shortage in the availability of human organs, xenografts have been attempted in humans with cardiac, renal, and hepatic failure, despite limited success. Use of xenografts, however, is regulated under law in various countries. In xenotransplant cases related to violation of transplantation law, determination of species of the source of tissue and organ(s) becomes highly essential. Random amplified polymorphic DNA (RAPD) protocols using six sets of arbitrary short-sequenced primers have been standardized for verifying claims of porcine cardiac and renal grafts in human transplantation cases. Six arbitrary primers used were found to generate unique amplicon patterns at 36 degrees C annealing temperature. Among the selected primers, a single primer set having the sequence 5'- GGTGCGGGAA -3' is found to be the most informative in discerning porcine tissue contamination in humans. The patterns obtained were consistent for a particular genome. The grafted organs in the studied case were analyzed to be of porcine origin.

Adult↗
PubMed2001

Effect of VMH lesion on sucrose-fed analgesia in formalin pain.

The ingestion of sucrose (ad libitum) produces an immediate analgesic response to phasic noxious stimuli. The underlying mechanism for the analgesic effect of sucrose is attributed to its palatability, which mediates analgesia probably by the release of beta-endorphin in the hypothalamus. The present study was designed to explore the role of ventromedial hypothalamus in the mediation of sucrose-fed analgesia. Adult male albino rats each received (20%) sucrose solution orally through a separate bottle until they had ingested 4-5 ml. Their behavioral responses to tonic noxious stimulus in a formalin test were studied in pre- and postsucrose-fed rats of control and in the VMH lesion groups. The average pain rating of a 60-min session significantly (p < 0.01) decreased after sucrose feeding in control rats, from 1.94 +/- 0.13 to 1.45 +/- 0.14, but sucrose feeding by the VMH lesion rats did not alter their tonic nociceptive response from a 1.70 +/- 0.07 presucrose-fed state to a 1.71 +/- 0.08 postsucrose-fed state. VMH lesion per se did not alter the nociceptive response in comparison with controls. The results suggest that sucrose feeding produces analgesia to tonic noxious stimulus, which is abolished by lesion of the VMH, thereby indicating a significant role of VMH in sucrose-fed analgesia.

Analgesia↗
PubMed2001

Pilomatrix carcinoma: case report and review of literature.

We report the case of a 57-year-old immunocompromised man with a pilomatrix carcinoma in his left forearm. Pilomatrix carcinoma is the rare malignant counterpart of pilomatrixoma. It has a potential for local recurrence and can metastasise to distant sites. We discuss the differential diagnosis of this rare tumour, and the difficulty in distinguishing this lesion from an atypical proliferating pilomatrixoma. Ultrastructural features of pilomatrix carcinoma are also discussed.

Carcinoma↗
PubMed2000

The critical role of the conserved Thr247 residue in the functioning of the osmosensor EnvZ, a histidine Kinase/Phosphatase, in Escherichia coli.

The histidine kinase/phosphatase EnvZ helps Escherichia coli adapt to osmotic shock by controlling the phosphorylation state of the transcription factor OmpR, which regulates the levels of the outer membrane porin proteins OmpF and OmpC. We examined the effects of mutating the highly conserved Thr(247) residue in EnvZ. Using purified C-terminal domains of wild-type and mutant EnvZ proteins, we demonstrate that Thr(247) plays a vital role in EnvZ function, variously affecting its autokinase and phosphotransferase activities, but mostly its function as a phosphatase. The cytoplasmic domain of EnvZ (EnvZc) is composed of three segments: the linker domain (residues 180-222), domain A (residues 223-289), and domain B (residues 290-450). It has been shown that the isolated domain A itself can dephosphorylate phosphorylated OmpR. Here we show that mutating Thr(247) to Arg in domain A abolishes its phosphatase activity. Furthermore, using an in vivo beta-galactosidase activity assay of Taz1-1 (hybrid of the aspartate receptor Tar and EnvZ) constructs of the Thr(247) mutants in RU1012 cells expressing ompC-lacZ, we demonstrate that the external signal primarily down-regulates the phosphatase activity of EnvZ. Of the nine EnvZc(T247X) mutants (X = Ser, Ala, Cys, Lys, Asn, Glu, Gln, Tyr, or Arg) analyzed, only Ser functionally substituted for Thr at this position, whereas all the others displayed constitutive expression of beta-galactosidase.

Amino Acid Sequence↗
PubMed2000

GHKL, an emergent ATPase/kinase superfamily.

An interesting recent development is the recognition of a novel ATP-binding superfamily that includes diverse protein families such as DNA topoisomerase II, molecular chaperones Hsp90, DNA-mismatch-repair enzymes MutL and histidine kinases. The most singular unifying feature of this superfamily is the unconventional Bergerat ATP-binding fold. The far-reaching significance of this commonality is still in the process of being explored.

Adenosine Triphosphatases↗
PubMed2000

A monomeric histidine kinase derived from EnvZ, an Escherichia coli osmosensor.

Histidine kinases function as dimers. The kinase domain of the osmosensing histidine kinase EnvZ of Escherichia coli consists of two domains: domain A (67 residues) responsible for histidine phosphotransfer and dimerization, and domain B (161 residues) responsible for the catalytic and ATP-binding function. The individual structures of these two domains have been recently solved by NMR spectroscopy. Here, we demonstrate that an enzymatically functional monomeric histidine kinase can be constructed by fusing in tandem two domains A and one domain B to produce a single polypeptide (A-A-B). We show that this protein, EnvZc[AAB], is soluble and exists as a stable monomer. The autophosphorylation and OmpR kinase activities of the monomeric EnvZc[AAB] are similar to that of the wild-type EnvZ, while OmpR-binding and phosphatase functions are reduced. V8 protease digestion and mutational analyses indicate that His-243 of only the amino proximal domain A is phosphorylated. Based on these results, molecular models are proposed for the structures of EnvZc[AAB] and the kinase domain of EnvZ. The present results demonstrate for the first time the construction of a functional, monomeric histidine kinase, further structural studies of which may provide important insights into the structure-function relationships of histidine kinases.

Bacterial Outer Membrane Proteins↗
PubMed1999

Solution structure of the homodimeric core domain of Escherichia coli histidine kinase EnvZ.

Escherichia coli osmosensor EnvZ is a protein histidine kinase that plays a central role in osmoregulation, a cellular adaptation process involving the His-Asp phosphorelay signal transduction system. Dimerization of the transmembrane protein is essential for its autophosphorylation and phosphorelay signal transduction functions. Here we present the NMR-derived structure of the homodimeric core domain (residues 223-289) of EnvZ that includes His 243, the site of autophosphorylation and phosphate transfer reactions. The structure comprises a four-helix bundle formed by two identical helix-turn-helix subunits, revealing the molecular assembly of two active sites within the dimeric kinase.

Amino Acid Sequence↗
PubMed1999

Histidine kinases: diversity of domain organization.

Histidine kinases play a major role in signal transduction in prokaryotes for the cellular adaptation to environmental conditions and stresses. Recent progress in the three-dimensional structure determination of two representative members of histidine kinases, EnvZ (class I) and CheA (class II), has revealed common structural features, as well as a kinase catalytic motif topologically similar to those of the ATP-binding domains of a few ATPases. They have also disclosed that there are significant differences in domain organization between class I and II histidine kinases, possibly reflecting their distinct locations, functions and regulatory mechanisms. In spite of this diversity, both class I and II histidine kinases use similar four-helix bundle motifs to relay phosphoryl groups from ATP to regulatory domains of response regulators. The previously known so-called transmitter domain of histidine kinase is further dissected into two domains: a CA (Catalytic ATP-binding) domain and a DHp (Dimerization Histidine phosphotransfer) domain for class I, or a CA domain and an HPt (Histidine-containing Phosphotransfer) domain for class II histidine kinases. From a comparative analysis of the CA domains of EnvZ, CheA and their ATPase homologues, the core elements of the CA domain have been derived. The apparent resemblance between DHp and HPt domains is only superficial, and significant differences between them are discussed.

Adenosine Triphosphate↗
PubMed1998

NMR structure of the histidine kinase domain of the E. coli osmosensor EnvZ.

Bacteria live in capricious environments, in which they must continuously sense external conditions in order to adjust their shape, motility and physiology. The histidine-aspartate phosphorelay signal-transduction system (also known as the two-component system) is important in cellular adaptation to environmental changes in both prokaryotes and lower eukaryotes. In this system, protein histidine kinases function as sensors and signal transducers. The Escherichia coli osmosensor, EnvZ, is a transmembrane protein with histidine kinase activity in its cytoplasmic region. The cytoplasmic region contains two functional domains: domain A (residues 223-289) contains the conserved histidine residue (H243), a site of autophosphorylation as well as transphosphorylation to the conserved D55 residue of response regulator OmpR, whereas domain B (residues 290-450) encloses several highly conserved regions (G1, G2, F and N boxes) and is able to phosphorylate H243. Here we present the solution structure of domain B, the catalytic core of EnvZ. This core has a novel protein kinase structure, distinct from the serine/threonine/tyrosine kinase fold, with unanticipated similarities to both heatshock protein 90 and DNA gyrase B.

Amino Acid Sequence↗