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Biomedical subjects

R K Singh

Publications and source records attributed to R K Singh.

At least 55 records · Page 3Linked to original sources
PubMed2004

An outbreak of sheep pox on a sheep breeding farm in Jammu, India.

An outbreak of sheep pox occurred in December 2001 on a sheep breeding farm in Jammu, India. The farm maintains three exotic breeds of sheep, i.e. American Merino, Rambouillet and Australian cross. The disease agent was confirmed as sheep pox virus by clinical and post-mortem examination as well as laboratory testing. Typical pock lesions were dispersed over the body of the affected animals with nodular lesions observed in the lung tissue of the dead animals. Sheep pox virus antigen and antibody were detected in infected tissue and convalescent sera, respectively, with serological tests. Viral deoxyribonucleic acid was extracted from the infected tissue and amplified using a diagnostic polymerase chain reaction. Sheep of the Rambouillet breed were found to be most susceptible to infection with morbidity and mortality rates of 26.9% and 8.3%, respectively. Morbidity and mortality rates in the entire flock were 18.4% and 6.3%, respectively. The grazing and migration pattern indicates that the disease was probably introduced to the farm by local sheep.

Animals↗
PubMed2004

A Vero cell-attenuated Goatpox virus provides protection against virulent virus challenge.

An Indian isolate of Goatpox virus (GTPV) was adapted and propagated in Vero cells for development of an attenuated virus. The virus was initially passaged in primary lamb testes cells and subsequently in Vero cells. At the 55th passage, the virus showed evidence of attenuation when tested for safety in seronegative goats. At this stage, the virus was found to be completely non-pathogenic. The virus was passaged further and the 60th passage was used for testing its immunogenicity in goats. The latter were inoculated with 10, 100 and 1000 TCID50 of the attenuated virus by intradermal (i.d.) route and challenged after 28 days with virulent GTPV. The attenuated virus produced no adverse reaction even at the highest dose and conferred complete protection even at the lowest dose against challenge with a high dose (2 x 10(6) of 50% skin-reactive dose SRD50) of virulent virus. Increased levels of virus-specific serum antibodies could be demonstrated by both indirect enzyme-linked immunosorbent assay (ELISA) and virus neutralization (VN) test in all the immunized goats. No horizontal transmission of the virus from the immunized to in-contact animals took place. Our results suggest that this attenuated virus could be a safe, immunogenic and potent candidate for developing a vaccine against goatpox.

Animals↗
PubMed2004

Development of a N gene-based PCR-ELISA for detection of Peste-des-petits-ruminants virus in clinical samples.

A highly sensitive N gene-based PCR-ELISA for the detection of Peste-des-petits-ruminants virus (PPRV) was developed. The RT-PCR yielded a digoxigenin (DIG)-labeled product of 336 bp comprising a sequence from PPRV N gene, which was then detected by ELISA. The assay could detect the viral RNA in PPRV-infected tissue culture fluids with a titer as low as 0.1 TCID(50)/ml. The assay is 10,000 times more sensitive than a classical RT-PCR combined with agarose gel electrophoresis. The assay could detect the virus in the clinical samples, which were negative by conventional sandwich ELISA (S-ELISA). The percentage positivity of the assay in detecting the virus in clinical samples was 66.2% compared to 48.6% for S-ELISA. The assay was more sensitive than S-ELISA also in detecting the virus in early as well as late phases of the disease. In addition, the assay could also be used for differential diagnosis of PPRV and Rinderpest virus (RPV).

Animals↗
PubMed2004

Predatory potential of Nepa cinerea against mosquito larvae in laboratory conditions.

Biocontrol potential of nepidae bug, Nepa cinerea against immature stages of Anopheles stephensi, Anopheles culicifacies, Culex quinquefasciatus and Aedes aegypti was studied under laboratory conditions. It was found that N. cinerea had the highest predation against An. stephensi followed by An. culicifacies, Cmx quinquefasciatus and Ae. aegypti. From the analysis, it was found that N. cinerea has good predation efficacy. It can be used as a biological control agent to control of mosquito breeding in integrated disease vector control programme.

Aedes↗
PubMed2003

55 kb plasmid and virulence-associated genes are positively correlated with Salmonella enteritidis pathogenicity in mice and chickens.

Twenty-four strains of Salmonella enteritidis, isolated from several outbreaks of salmonellosis from different poultry farms in India, were checked for the plasmid profile and detection of virulence gene(s) by PCR. Most of the strains contained only a single plasmid of 55 kb. Additional plasmids of 23.2 kb and 8.7 kb were seen in one of the strains, and another strain carried only two plasmids of 23.2 kb and 8.7 kb. Four strains did not carry any plasmid. PCR amplification showed the presence of virulence-associated genes in all the isolates harbouring the 55 kb plasmid. Intraperitoneal inoculation of mice, with most of the strains carrying the 55 kb plasmid, caused 100% mortality. Most strains lacking the 55 kb plasmid were avirulent. In chickens, oral inoculation of the S. enteritidis strains carrying the 55 kb plasmid produced 40-100% mortality, with characteristic signs of salmonellosis. Oral inoculation of strains lacking the 55 kb plasmid did not cause any mortality. Hence, it appears that the large plasmid of S. enteritidis probably contributes towards virulence in mice and chickens.

Animals↗
PubMed2003

Ultrafast MR imaging in pediatric neuroradiology.

PURPOSE: To compare the diagnostic information obtained from ultrafast MR imaging with standard MR imaging techniques in pediatric neuroradiology. The goal was to judge whether ultrafast methods can be used to replace standard methods and reduce the need for sedation or general anesthesia as a result of the considerably shorter scan times. MATERIAL AND METHODS: Our prospective study involved 125 patients. Routine clinical imaging was performed along with two ultrafast methods. Single shot fast spin echo (SSFSE) was used to give T2-weighted images and an echo planar imaging (EPI) sequence to provide a T1-weighted images. The ultrafast images were presented to an experienced neuroradiologist who was also given the information present on the initial referral card. These reports based on the ultrafast images were then compared with the formal radiologic report made solely on the basis of the standard imaging. RESULTS: The overall sensitivity and specificity for ultrafast imaging when compared to the reference standard were 78% and 98% with positive and negative predictive values of 98% and 76%. Pathologies characterized by small areas of subtle T2 prolongation were difficult or impossible to see on the ultrafast images but otherwise they provided reliable information. CONCLUSIONS: This paper demonstrates that ultrafast MR imaging can diagnose many pediatric intracranial abnormalities as well as standard methods. Anatomic resolution limits its capacity to define subtle developmental anomalies and contrast resolution limitations of the ultrafast methods reduce the detection of pathology characterized by subtle T2 prolongation.

Brain Diseases↗
PubMed2003

Molecular characterization and quantitative analysis of superoxide dismutases in virulent and avirulent strains of Aeromonas salmonicida subsp. salmonicida.

Aeromonas salmonicida subsp. salmonicida is a facultatively intracellular gram-negative bacterium that is the etiological agent of furunculosis, a bacterial septicemia of salmonids that causes significant economic loss to the salmon farming industry. The mechanisms by which A. salmonicida evades intracellular killing may be relevant in understanding virulence and the eventual design of appropriate treatment strategies for furunculosis. We have identified two open reading frames (ORFs) and related upstream sequences that code for two putative superoxide dismutases (SODs), sodA and sodB. The sodA gene encoded a protein of 204 amino acids with a molecular mass of approximately 23.0 kDa (SodA) that had high similarity to other prokaryotic Mn-SODs. The sodB gene encoded a protein of 194 amino acids with a molecular mass of approximately 22.3 kDa that had high similarity to other prokaryotic Fe-SODs. Two enzymes with activities consistent with both these ORFs were identified by inhibition of O(2)(-)-catalyzed tetrazolium salt reduction in both gels and microtiter plate assays. The two enzymes differed in their expression patterns in in vivo- and in vitro-cultured bacteria. The regulatory sequences upstream of putative sodA were consistent with these differences. We could not identify other SOD isozymes such as sodC either functionally or through data mining. Levels of SOD were significantly higher in virulent than in avirulent strains of A. salmonicida subsp. salmonicida strain A449 when cultured in vitro and in vivo.

Aeromonas↗
PubMed2003

Lucio's phenomenon.

Explore the source record for details and available documents.

Anti-Bacterial Agents↗
PubMed2003

Laboratory studies on the predatory potential of dragon-fly nymphs on mosquito larvae.

Biocontrol potential of dragonfly nymph, Brachythemis contaminata Fabricius against the larvae of Anopheles stephensi, Culex. quinquefasciatus and Aedes aegypti was studied under laboratory conditions. It was found that dragonfly nymph had highest predation efficacy against An. stephensi followed by Cx. quinquefasciatus and Ae. aegypti. Feeding rate increased with decrease in prey size/stage. Analysis of data indicated that dragonfly nymphs have good predatory potential and can be used as a biological control agent for control of mosquito breeding.

Animals↗
PubMed2002

A multiplex-PCR for the differentiation of Mycobacterium bovis and Mycobacterium tuberculosis.

A multiplex-polymerase chain reaction (PCR) assay based on one-step amplification and detection of two different mycobacterial genomic fragments was designed for differentiation of Mycobacterium bovis and Mycobacterium tuberculosis. The oligonucleotide primers were chosen from a 500-bp genomic fragment which is well conserved in M. bovis and the pncA gene (based on M. tuberculosis-specific nucleotide polymorphism, a cytosine residue at position 169), specific for M. tuberculosis. The multiplex-PCR allowed detection of a single product of 500 bp in M. bovis isolates while M. tuberculosis isolates generated a single product of 185 bp, with or without an additional product of 500 bp. None of the atypical mycobacterial isolates revealed any amplification products. The method was found to be highly specific and could detect as little as 20 pg of pure DNA. This multiplex-PCR assay, based on the 500-bp fragment and the pncA gene, may be very useful for the rapid and specific differentiation of these two closely related mycobacteria and easy to use in medical and veterinary microbiological laboratories.

Amidohydrolases↗
PubMed2002

Supercritical fluid extraction of lycopene from tomato processing byproducts.

Tomato seeds and skins acquired from the byproduct of a local tomato processing facility were studied for supercritical fluid extraction (SFE) of phytochemicals. The extracts were analyzed for lycopene, beta-carotene, alpha-carotene, alpha-tocopherol, gamma-tocopherol, and delta-tocopherol content using high-performance liquid chromatography-electrochemical detection and compared to a chemically extracted control. SFEs were carried out using CO(2) at seven temperatures (32-86 degrees C) and six pressures (13.78-48.26 MPa). The effect of CO(2) flow rate and volume also was investigated. The results indicated that the percentage of lycopene extracted increased with elevated temperature and pressure until a maximum recovery of 38.8% was reached at 86 degrees C and 34.47 MPa, after which the amount of lycopene extracted decreased. Conditions for the optimum extraction of lycopene from 3 g of raw material were determined to be 86 degrees C, 34.47 MPa, and 500 mL of CO(2) at a flow rate of 2.5 mL/min. These conditions resulted in the extraction of 61.0% of the lycopene (7.19 microg lycopene/g).

Carotenoids↗
PubMed2002

Studies on essential oils: part 10; antibacterial activity of volatile oils of some spices.

The essential oils extracted from the seeds of seven spices, Anethum graveolens, Carum capticum, Coriandrum sativum, Cuminum cyminum, Foeniculum vulgare, Pimpinella anisum and Seseli indicum have been studied for antibacterial activity against eight pathogenic bacteria, causing infections in the human body. It has been found that the oil of C. capticum is very effective against all tested bacteria. The oil of C. cyminum and A. graveolens also gave similar results. These oils are equally or more effective when compared with standard antibiotics, at a very low concentration.

Anethum graveolens↗
PubMed2002

Antigenic relationships within the genus Salmonella as revealed by anti-Salmonella enteritidis monoclonal antibodies.

A panel of 38 monoclonal antibodies (MAbs) that react with outer membrane proteins (OMPs) of Salmonella enteritidis was produced. On the basis of their binding pattern in ELISA, the MAbs were divided into three groups. The first group, consisting of 15 MAbs, was found to be Salmonella-specific as they did not cross-react with Escherichia coli or Pasteurella multocida. The second group of 15 MAbs cross-reacted with E. coli but not with P. multocida, reflecting the closer antigenic relationship of E. coli with Salmonella. The third group of 8 MAbs cross-reacted with both E. coli and P. multocida, indicating that the antigenic determinants identified by these MAbs are conserved in all the three genera. The antigenic relationship of the Salmonella serovars (S. enteritidis, S. gallinarum, S. typhimurium, S. dublin, S. agona, S. indiana and S. choleraesuis) was studied using OMPs prepared from them and the anti-S. enteritidis MAbs. Three MAbs appeared to be specific for S. enteritidis as they did not cross-react with any of the other Salmonella serovars. Twelve of the 38 MAbs cross-reacted with all the serovars tested. Six of these were specific to the Salmonella genus as they did not cross-react with any of the other Gram-negative bacteria tested. The reactivity pattern of the other MAbs indicated that S. gallinarum was antigenically close to S. enteritidis, followed in order by S. dublin, S. agona, S. typhimurium and S. indiana, whereas S. choleraesuis seemed to be antigenically quite distant from S. enteritidis.

Animals↗
PubMed2002

MHC-DRB exon 2 allele polymorphism in Indian river buffalo (Bubalus bubalis).

The polymorphism of the major histocompatibility complex (MHC) class II DRB gene of riverine buffalo (Bubalus bubalis) was studied. Second exon sequences from the buffalo DRB locus, homologous to the cattle DRB3 gene, were amplified and characterized. A combination of single strand conformation polymorphism (SSCP) and heteroduplex analysis (HA) in a non-denaturing gel was used to identify new DRB second exon sequences. SSCP, HA and finally sequencing allowed the identification of 22 MHC-DRB exon 2 alleles from 25 unrelated Indian river buffalo. These are the first river buffalo DRB second exon sequences reported. A high degree of polymorphism in the sequences encoding the peptide binding regions was observed and some amino acid substitutions were found unique to the river buffalo.

Amino Acid Sequence↗
PubMed2002

Prospective analysis of the association of infection with CagA bearing strains of Helicobacter pylori and coronary heart disease.

OBJECTIVE: To see whether it was possible to replicate in a prospective study the association recently reported between infection with the more virulent (type 1) cytotoxin associated gene A (CagA) antigen carrying strains of Helicobacter pylori and increased risk of coronary heart disease. DESIGN AND SETTING: Nested case-control study in a clinical outcomes trial. SUBJECTS: Participants in the West of Scotland coronary prevention study. METHODS: H pylori CagA serological status was determined in plasma samples of 201 subjects (cases) who subsequently had a coronary event during follow up and in 414 subjects (controls) matched for age and smoking who remained event-free, using a semiquantitative commercial enzyme linked immunosorbent assay (ELISA) kit against the p120 antigen of CagA. RESULTS: 105 (52%) in the case group and 176 (43%) in the control group were seropositive (odds ratio (OR) 1.49, 95% confidence interval (CI) 1.06 to 2.10, p = 0.022). The association remained significant after adjustment for blood pressure, body mass index, plasma concentrations of low density lipoprotein and high density lipoprotein cholesterol, history of hypertension and diabetes, statin treatment, and socioeconomic status (OR 1.51, 95% CI 1.06 to 2.16, p = 0.023). Baseline inflammatory markers (white cell count, C reactive protein, fibrinogen) were not significantly increased in either H pylori CagA positive cases or controls. CONCLUSIONS: The findings provide support from a prospective study for the hypothesis that there is an association between infection with CagA bearing strains of H pylori and coronary heart disease. The mechanism(s) underlying the association remain to be elucidated.

Antigens, Bacterial↗