Biomedical subjects
Publications and source records attributed to A Rai.
We report a case of neglected, strangulated, inguinal hernia in a middle-aged male, which presented as a scrotal fecal fistula. This is the first such case reported in an adult. The patient was treated by resection and anastamosis of the ileum, local debridement of the scrotum and Shouldice repair for the inguinal defect.
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Rabies virus (RV) glycoprotein (gp) consists of three domains: cytoplasmic, transmembrane and ectodomain. It occurs in a complete, membrane-bound form within the infected cell, but it is released from them in a deleted, secreted form lacking the transmembrane domain. This study was performed to test the importance of the transmembrane domain for the capability of the RV gp gene, introduced into mice via a recombinant plasmid (DNA vaccine), to induce immune response and protection against challenge. Although the antibody response to the secreted form of gp was higher than that to complete gp, the protective efficacy of the respective DNA vaccine against challenge was not better than that of the DNA vaccine inducing complete gp. This indicates that the transmembrane domain of RV gp is important for generating protection against rabies and should be present in RV DNA vaccines.
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Rabies virus glycoprotein is a type I transmembrane protein exposed on the surface on the mature virus particle that induces virus neutralizing antibodies. In the present study, 60 amino acid C-terminal hydrophobic anchor (transmembrane) and cytoplasmic domains of glycoprotein were deleted from full-length glycoprotein and fused with polyhistidine tag. The N-terminal viral signal peptide was also replaced with CD33 signal peptide for efficient secretion in mammalian cells. Following transfection of Madin Darby bovine kidney (MDBK) cells with plasmid encoding this soluble form of glycoprotein, polyclonal populations of stably transfected resistant cells were obtained after G418 selection. The protein was expressed as a glycosylated protein and secreted outside the cells utilizing N-terminal CD33 signal peptide. The secreted soluble glycoprotein was purified from cell culture supernatant by Ni--agarose affinity chromatography utilizing C-terminal polyhistidine tag. Like full-length glycoprotein, the expressed recombinant soluble glycoprotein was found to be immunogenic when injected in rabbits. In this study, we have assessed the potential of recombinant soluble glycoprotein as diagnostic antigen in ELISA and found that this recombinant protein can be used as diagnostic antigen in ELISA for detecting anti-glycoprotein antibodies in immunized host.
Aluminum nanoparticles are being considered as a possible fuel in advanced energetic materials application. Of considerable interest therefore is a knowledge of just how reactive these materials are, and what the effect of size on reactivity is. In this paper we describe results of size resolved oxidation rate using a recently developed quantitative single particle mass spectrometer (SPMS). Aluminum nanoparticles used were either generated by DC Arc discharge or laser ablation, or by use of commercial aluminum nanopowders. These particles were oxidized in an aerosol flow reactor in air for specified various temperatures (25-1100 degrees C), and subsequently sampled by the SPMS. The mass spectra obtained were used to quantitatively determine the elemental composition of individual particles and their size. We found that the reactivity of aluminum nanoparticles is enhanced with decreasing primary particle size. Aluminum nanoparticles produced from the DC Arc, which produced the smallest primary particle size (approximately 19 nm), were found to be the most reactive (approximately 68% aluminum nanoparticles completely oxidized to aluminum oxide at 900 degrees C). In contrast, nanopowders with primary particle size greater than approximately 50 nm were not fully oxidized even at 1100 degrees C (approximately 4%). The absolute rates observed were found to be consistent with an oxide diffusion controlled rate-limiting step. We also determined the size-dependent diffusion-limited rate constants and Arrehenius parameters (activation energy and pre-exponential factor). We found that as the particle size decreases, the rate constant increases and the activation energy decreases. This work provides a quantification of the known pyrophoric nature of fine metal particles.
A recombinant plasmid pTargeT.rabgp containing the glycoprotein (G) gene of Rabies virus (RV) was constructed and produced for immunogenicity studies on mice and dogs. The mice immunized twice with 50 microg or 100 microg of pTargeT.rabgp intramuscularly (i.m.), showed a serum antibody titer of 256 or 64, respectively 14 days post immunization (p.i.). When the vaccinated mice were challenged at 14 days p.i. with RV i.c., they were protected in 81.25% or 87.5%, respectively. A positive cell mediated immune response was observed by lymphocyte proliferation assay and macrophage migration inhibition test. These results indicate that the pTargeT.rabgp plasmid can be used as a rabies DNA vaccine.
The degree of genetic variability among Hepatitis C virus strains circulating in India is currently unknown. In order to get insight into this matter, sequence data obtained from the 5' non coding region from 8 patients from New Delhi were compared with sequences from 16 HCV isolates from different geographic locations of India. The phylogenetic analysis of most prevalent genotypes revealed the presence of novel HCV variants in type 1 strains.
Genomic variability within the sequences of VP1/2A junction among polioviruses from across the globe has revealed the existence of several endemic genotypes and their epidemiological inter-relationships; but such data on Indian isolates are scanty. The present work was intended to ascertain the persistence and transmission pattern of different genotypes of wild type 1 polioviruses circulating in India. Forty-eight wild type 1 poliovirus isolates obtained from different parts of India during 1996-8 were subjected to RT-PCR and nucleotide sequencing using M13 tailed primers. A 293 base pair region was amplified and sequenced for genetic variation study. Considering the 15% divergence of the sequences from Sabin 1, the isolates from six different states of India confirmed a single dominant genotype 4. Phylogenetic analysis revealed the circulation and active inter-state transmission of many genetically distinct strains of wild poliovirus type 1 belonging to genotype 4. This warrants the need for insisting on more efficient surveillance mechanisms so as to assess the impact of an extensive pulse polio immunization programme in India.
Previously considered solely as the laboratory contaminants and normal flora of skin in man, coagulase negative Staphylococci are now a major cause of nosocomial and opportunistic infections. This study was conducted at IGIMS, Patna to find out the coagulase negative Staphylococcus isolates from urine and their antimicrobial resistance. In a period of ten months, the relative frequency of main coagulase negative Staphylococci were as follows--Staphylococcus epidermidis-45.90%, Staphylococcus saprophyticus 34% and Staphylococcus haemolyticus-8.50%. others were 11.60%. most of the Staphylococcus saprophyticus was isolated from young female patients suffering from uncomplicated acute cystitis and Staphylococcus epidermidis was mainly from patients with indwelling catheters and complicated cases. Staphylococcus saprophyticus showed the highest sensitivities to all the antimicrobials whereas Staphylococcus haemolyticus had the highest resistance rates. 66.6% of staphylococcus epidermidis and 60% of staphylococcus haemolyticus were resistant to oxacillin, whereas only 10% of staphylococcus saprophyticus resistant and 90% were sensitive to it. As is in the emerging state, vancomycin resistance was very less but in future it may cause a major problem to treat these cases. So this area needs further exploration.
Genetic linkage calculations can be time consuming, even on a fast computer. The ability to collect large family pedigrees has increased the magnitude of linkage computations. Sequential genetic algorithms have many successful applications in very different domains, but they have a main drawback in their utilization. Evaluations are very time-consuming, e.g., a pedigree consisting of 55 nodes takes about 70 min on a DEC-Alpha processor and about 270 min on a 166 MHz Pentium for certain likelihood calculations. This time increases exponentially with the increase in the size of the pedigree. In order to solve these shortcomings and to study new models of higher efficiency and efficacy, parallel platforms are being used for genetic programs. LINKAGE is a software package for performing genetic likelihood calculations; FASTLINK is an improved, faster version of it. This paper provides a parallel implementation of the "Linkmap" program (one of the four programs in LINKAGE/FASTLINK) for a heterogeneous environment, using a static and a dynamic strategy for task allocation. It was found that the increased performance by the dynamic strategy was close to the estimated maximum speed up.
To study the genetic variability and to detect evolutionary changes and movement of dengue 2 (DEN-2) strains, nucleotide sequencing of the envelope protein gene and the nonstructural protein 1 gene junction was performed for 9 isolates from the 1996 Delhi epidemic and 1 isolate from the 1967 Delhi epidemic. The epidemic strains had a divergence of 10%-11% from the 1967 strains, but were quite similar to DEN-2 isolates from Seychelles, Somalia, and Torres Strait. In addition, the sequence data were compared to the prototype DEN-2 strain, New Guinea C, and other published DEN-2 sequences from different parts of the world. The phylogenetic analysis by the Molecular Evolutionary Genetics Analysis program suggests that the 1996 Delhi isolates of DEN-2 were genotype IV. The 1967 isolate was similar to a 1957 isolate of DEN-2, P9-122, from India, and was classified as genotype V. This study indicates that earlier DEN-2 strains of genotype V have been replaced by genotype IV.
Hypoxemia is common during various endoscopic procedures and may result from a variety of causes. These causes range from benign and otherwise easily reversible events like oversedation to potentially life threatening complications such as pneumothorax. Although pneumothorax has been reported secondary to gastrointestinal perforation as a complication of various therapeutic endoscopic procedures, there has been no report of pneumothorax without perforation. We report a case of a patient who developed severe hypoxemia and hemodynamic instability during diagnostic upper endoscopy as a result of pneumomediastinum and tension pneumothorax in the absence of any signs of gastrointestinal perforation and comment on various possible mechanisms. Immediate endotracheal intubation and bilateral chest tube placement resulted in prompt return of the patient's oxygenation and vital signs back to normal. This report enlarges the list of possible causes of hypoxemia during endoscopy and shows the importance of early and prompt recognition, which allowed directed therapy with a good outcome.
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Three infectious bursal disease virus (IBDV) isolates were adapted to culture in chick embryo fibroblast cells in which they produced a cytopathic effect. The isolates were identified as IBDV by virus neutralization tests using a standard hyperimmune serum against infectious bursal disease, physicochemical properties and their pathogenicity in chick embryos and chicks. The IBDV S394 strain was antigenically different from IBDV S194/IBDV S494 as well as from the IBDV Intermediate Georgia strain, one of the vaccine strains in use in India.
Polymerase chain reaction (PCR) technique was applied to detect BHV-1 in bovine semen inoculated with BHV-1. The technique was found to be 10(6) times more sensitive than a non-isotopic dot-blot hybridization method in detecting viral genomic DNA. Of the three primer pairs used, the one chosen from glycoprotein gC appeared to be most sensitive as it could detect up to 0.01 TCID50 of BHV-1 in the semen. The technique could be useful in screening breeding bulls or samples of frozen semen prior to use in artificial insemination.
To investigate the relationship between isoniazid resistance and HIV infection in patients with tuberculosis, we evaluated data in the Los Angeles County tuberculosis registry on 1,506 patients for whom drug susceptibility results were available. Among 235 HIV-infected patients, isoniazid resistance was less common than in 1,271 patients who were HIV-seronegative or who had not been tested for HIV, with an unadjusted odds ratio of 0.3. After adjustment for other factors that affect drug resistance (ethnicity, country of birth, prior diagnosis of tuberculosis, and cavitation), the frequency if isoniazid resistance remained lower than that in patients without HIV infection, with an odds ratio of 0.4 (95% confidence interval, 0.2 to 0.8; p = 0.02). We conclude that in Los Angeles, a setting where there is no ongoing outbreak of drug-resistant tuberculosis, isoniazid-resistant tuberculosis is not more common in HIV-infected patients.