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Biomedical subjects

P Roy

Publications and source records attributed to P Roy.

At least 271 records · Page 15Linked to original sources
PubMed1991

Detection of bluetongue virus RNA by in situ hybridization: comparison with virus isolation and antigen detection.

An in situ nucleic acid hybridization (ISH) technique was developed to detect bluetongue virus (BTV) RNA in cell culture. The sensitivity of the ISH technique was compared with virus isolation (VI) and antigen detection, using an indirect fluorescent-antibody (IFA) or an enzyme immunocytoassay (EICA) technique, for detection of 5 BTV serotypes indigenous to the United States. The VI was the most sensitive technique, detecting BTV early after infection of the cells. The IFA and EICA were of similar sensitivity; BTV antigen could be detected shortly after demonstration of virus by isolation. The sensitivity of ISH for detection of BTV-17 was equivalent to that of antigen detection. The ISH was not as sensitive as VI or antigen detection when assaying for the other BTV serotypes.

Animals↗
PubMed1991

Enterotoxigenic Klebsiella pneumoniae in acute childhood diarrhoea.

K. pneumoniae strains recovered as pure or predominant isolate from stool specimens of 50 children below three years of age, presenting with acute watery diarrhoea, were studied for heat-labile enterotoxin production. Twenty three (46%) of the 50 crude toxin concentrates showed positivity in rabbit ileal loops and skin permeability tests. Antigenically 17 (34%) and 20 (40%) of the toxin extracts reacted with immuno-purified anti H-LT antibody in latex particle agglutination and immuno-dot blot assays respectively. Polyacrylamide-gel electrophoresis, Western-blotting and enzyme-immunoassay revealed heat-labile enterotoxin and its subunits in 19 (68%) of 28 extracts tested. In 5 of 10 strains tested the toxigenicity could be transferred to recipient Escherichia coli J-35 in plasmid transfer experiments. Klebsiella induced enterotoxigenic diarrhoea and produced a heat-labile toxin which seems to be biologically, antigenically and possibly genetically related to the heat-labile toxin of the cholera-coli family.

Acute Disease↗
PubMed1991

A comparison of controlled release metoclopramide and domperidone in the treatment of nausea and vomiting.

Dopamine antagonists are effective anti-emetics. Domperidone does not readily cross the blood-brain barrier and is less likely to cause central nervous system side-effects than metoclopramide. However, a direct comparison of the safety and efficacy of the two drugs has not hitherto been made. Ninety-five patients, with symptoms of nausea and vomiting due to a variety of oesophageal or gastric disorders, were recruited into a randomised, double-blind, three-part, parallel-group comparative study of controlled release metoclopramide 15 mg (Gastrobid Continus tablets, Napp Laboratories) given twice daily, and domperidone 10 mg or 20 mg given three times daily. Assessments for nausea, vomiting, reflux symptoms and adverse events were made on entry to the study. Patients were randomly allocated to one of the three treatment regimes for a period of seven days, throughout which daily symptomatology and use of escape medication were recorded on a diary card. At the end of the treatment period, nausea, vomiting and reflux symptoms, adverse events and a global assessment of patients' symptom control were recorded by the investigator. Both controlled release metoclopramide and high and low dose domperidone significantly reduced symptoms of belching, flatulence, distension, heartburn, regurgitation, reflux, nausea and vomiting compared to baseline. There were no significant differences between the three treatments in efficacy or in the number and severity of side-effects.

Delayed-Action Preparations↗
PubMed1990

Effect of mRNA secondary structure on the efficiency of translational initiation by eukaryotic ribosomes.

We have used site-directed mutagenesis to determine whether the structural context surrounding the AUG triplet influences its ability to be selected as an initiation codon by the eukaryotic preinitiation complex. AUG triplets were introduced in a loop and stem structure naturally occurring at the midpoint of the 129-nucleotides-long 5'-untranslated region of the porcine proopiomelanocortin mRNA; one AUG triplet was inserted in the loop while another was inserted in the stem of the hairpin structure. The proopiomelanocortin cDNA and the mutant cDNAs were inserted downstream from the early promoter of an expression vector derived from simian virus 40 (SV40) and transfected into monkey kidney COS-1 cells. Analysis of the proopiomelanocortin-related peptides present in the culture medium 72 h after transfection revealed that both mutant cDNAs direct the synthesis of more proopiomelanocortin than the non-mutant cDNA. The increased translational efficiency observed with both mutants is probably due to the decreased secondary structures of the shortened 5'-untranslated region. In addition, comparison of the two mutants indicates that the mutant mRNA with the AUG triplet inserted in the loop region of the hairpin structure directs the synthesis of approximately 75% more proopiomelanocortin than the mutant mRNA with the AUG triplet inserted in the stem region of the same hairpin structure, supporting a role for the structural context in the efficiency of translational initiation.

Animals↗
PubMed1990

High level expression of the two outer capsid proteins of bluetongue virus serotype 10: their relationship with the neutralization of virus infection.

DNA representing RNA segments 2 and 5 of bluetongue virus (BTV) serotype 10, corresponding to the genes that code for the outer capsid proteins VP2 and VP5, have been inserted into a baculovirus transfer vector in lieu of the coding region of the polyhedrin gene of Autographa californica nuclear polyhedrosis virus (AcNPV). After co-transfection of Spodoptera frugiperda cells with wild-type AcNPV DNA in the presence of the recombinant transfer vector DNAs polyhedrin-negative recombinant baculoviruses were recovered. When S. frugiperda cells were infected with these recombinant viruses proteins of similar size and antigenic properties to BTV VP2 and VP5 were synthesised. The recombinant VP2, but not the recombinant VP5, was shown to be capable of inducing antibodies that neutralized the infectivity of BTV-10 in vitro.

Antibodies, Viral↗
PubMed1990

The association of cutaneous malignant melanoma with the use of sunbeds and sunlamps.

Data are presented from a large case-control study (583 cases, 608 controls) to estimate the association of melanoma with the use of sunbeds and sunlamps. Odds ratios of 1.88 and 1.45 were found for ever having used a sunbed or sunlamp in males and females, respectively, which was statistically significant in males and of borderline significance in females. These effects persisted when adjustments were made for age and a variety of potential confounders. The effect was slightly stronger for lentigo maligna and for lesions of the face, head, neck, and arms. The risk was greater and significant for both sexes for domestic use of sunbeds/sunlamps, and increased with duration and amount of use. A comparison of 43 cases interviewed before a diagnosis of melanoma had been made with the other 540 cases suggests that recall bias was not responsible for the association. The authors conclude that use of artificial tanning devices appears to be a risk factor for melanoma.

Adult↗
PubMed1990

Purification and characterization of the major group-specific core antigen VP7 of bluetongue virus synthesized by a recombinant baculovirus.

The major core protein, VP7, of bluetongue virus serotype 10 (BTV-10) has been purified from insect cells infected with a genetically manipulated recombinant baculovirus. The high level expression of VP7 (in excess of 100 mg per litre of culture) and its presence in the soluble fraction of infected cells following lysis by detergent has allowed the purification of the protein virtually to homogeneity (95%) by a simple two-step procedure of ammonium sulphate fractionation and ion-exchange chromatography. The purified antigen is highly immunogenic and has been shown in an ELISA to be reactive with antisera of 24 BTV serotypes (1 to 24) as well as with an antiserum raised to African horsesickness virus type 4 (AHSV-4), a representative of another serogroup of orbiviruses. In confirmation of these data a monospecific antiserum raised with the expressed product has been shown by Western blot analyses to react with other BTV serotypes as well as with two serotypes of epizootic haemorrhagic disease virus (EHDV-1 and EHDV-2), a closely related orbivirus. The data indicated that VP7 is a highly conserved protein amongst BTV serotypes and at least partly conserved amongst three serogroups of orbiviruses.

African Horse Sickness Virus↗
PubMed1990

Biophysical studies on the morphology of baculovirus-expressed bluetongue virus tubules.

Bluetongue virus tubules were purified from Spodoptera frugiperda cells infected with a recombinant baculovirus containing the NS1 gene from bluetongue virus serotype 10, and expressed under control of the Autographa californica nuclear polyhedrosis virus polyhedrin promoter. These tubules were subjected to a variety of chemical and physical treatments and the resulting effects on tubule morphology were examined by electron microscopy. A number of morphological similarities were noted between bluetongue virus tubules and cellular microtubules despite a lack of homology between the component proteins at the primary sequence level. A possible multistranded helical configuration is proposed for the tubule structure.

Animals↗
PubMed1990

Synthesis of bluetongue virus-encoded phosphoprotein and formation of inclusion bodies by recombinant baculovirus in insect cells: it binds the single-stranded RNA species.

A DNA clone of RNA segment 8 (S8) of bluetongue virus type 10 (BTV-10), an orbivirus member of the Reoviridae family has been expressed to high levels (20 mg/1 x 10(9) cells) using an Autographa californica nuclear polyhedrosis virus expression vector (pA-cYM1). The expressed protein is similar to the authentic BTV phosphoprotein NS2, in its size, antigenicity, and also the manner of phosphorylation (e.g. same peptides and residues). Both mammalian and insect cell-derived NS2 proteins are phosphorylated at serine residues only. Using affinity column chromatography and a gel retardation assay, the expressed protein has been shown to possess ssRNA-binding ability, a property which is shown to be independent of the phosphorylation state of the protein. In immunoelectron micrographic studies, gold-labelled anti-expressed NS2 antibodies have been used to localize the NS2 protein within the viral inclusion bodies (VIBs) in BTV-infected mammalian cells. Large inclusion bodies, morphologically similar to VIBs, have been identified in the recombinant virus-infected Spodoptera frugiperda cells. These structures have been shown to react with gold-labelled anti-BTV-10 antisera, demonstrating the first direct evidence of the origin of inclusion bodies in orbivirus infection.

Animals↗