Search PubMed⌕ Search

Biomedical subjects

P Roy

Publications and source records attributed to P Roy.

At least 325 records · Page 18Linked to original sources
PubMed1988

Complete sequence of neutralization protein VP2 of the recent US isolate bluetongue virus serotype 2: its relationship with VP2 species of other US serotypes.

In order to determine the relationship between the most recently isolated bluetongue virus serotype (BTV-2), and other US serotypes, the complete nucleotide sequence was determined from cDNA clones representing the L2 dsRNA of BTV-2, the gene that codes for the outer capsid neutralization antigen (VP2). The predicted amino acid sequence of the protein was compared with the VP2 sequences of the US serotypes BTV-10, BTV-11, BTV-13 and BTV-17. The VP2 protein of BTV-2 was found to exhibit 47% homology with the VP2 species of BTV-13, but only 40-41% homology with the VP2 species of earlier US isolates, BTV-10-, and -17. However, Diagon comparisons and hydropathic plots of all five VP2 species indicated that all of them are structurally very similar.

Amino Acid Sequence↗
PubMed1988

Bluetongue virus tubules made in insect cells by recombinant baculoviruses: expression of the NS1 gene of bluetongue virus serotype 10.

Bluetongue virus (BTV) forms tubules in mammalian cells. These tubules appear to be composed of only one type of protein, NS1, a major nonstructural protein of the virus. To obtain direct evidence for the origin of the tubules, the complete M6 gene of BTV serotype 10 was inserted into the baculovirus transfer vector pAcYM1, so that it was under the control of the polyhedrin promoter of Autographa californica nuclear polyhedrosis virus. After cotransfection of Spodoptera frugiperda cells with wild-type A. californica nuclear polyhedrosis virus DNA in the presence of recombinant transfer vector DNA, polyhedrin-negative baculoviruses were recovered. When S. frugiperda cells were infected with one of the derived recombinant viruses, a protein similar in size and antigenic properties to the authentic BTV NS1 protein was made (representing ca. 50% of the stained cellular proteins). The protein reacted with BTV antibody and formed numerous tubular structures in the cytoplasm of S. frugiperda cells. The tubular structures have been purified to homogeneity from infected-cell extracts by gradient centrifugation. By enzyme-linked immunosorbent assay, the recombinant virus antigen has been used to identify antibodies to five United States BTV serotypes in infected sheep sera, indicating the potentiality of the expressed protein as a group-reactive antigen in the diagnosis of BTV infections.

Animals↗
PubMed1988

Tissue tropism and target cells of bluetongue virus in the chicken embryo.

In situ cytohybridization was used to determine the tissue tropism and target cells for replication of bluetongue virus (BTV) in the developing chicken embryo. Hybridization with a biotinylated probe specific for segment 3 of BTV serotype 17 detected viral replication in embryos inoculated with U.S. serotypes 2, 10, 11, 13, and 17 or sheep blood containing a BTV field strain. At the final stages of infection, when the embryos were hemorrhagic, viral infection could consistently be detected in the brain, kidney, spinal cord, heart, lung, and liver, with the brain and kidney most severely affected. Other tissues, such as the retina, skin, tongue, and intestinal villi, also supported viral replication in some embryos. Greater concentrations of virus tended to be localized within epithelial cells, such as those lining the kidney tubules and tertiary bronchi of the lungs. Kinetics studies with BTV serotypes 11 and 17 and a field strain indicated that within 24 h after inoculation, viral replication occurred initially in the brain and kidney. By 48 h, viral replication was also detected in the lungs, heart, and spinal cord, with the liver being severely infected by 72 h. Low levels of hybridization could be detected in embryos infected with epizootic hemorrhagic disease virus, which is antigenically related to BTV.

Animals↗
PubMed1988

[Acid gastroesophageal reflux in the child with intubation, artificial respiration and continuous nutrition. Apropos of 28 cases].

Continuous monitoring of distal oesophageal pH and oesophagoscopy were performed in 28 children aged 15 days to 12 years (mean: 14 months) intubated and ventilated for bronchiolitis (7), pneumonia (8), epiglotitis (2), neurological distress (8), whooping cough (2) or recurrent apneic spells (1). Esophageal pH was studied 2-8 days (mean: 2 days) after intubation; its duration was 12-23 h 50 min (M: 22 h). An abnormal gastroesophageal reflux was presumed when the percent of total monitoring time during which the esophageal pH fell below 4.0 was above 5.2%. The esophagoscopy was carried out on the day following the pH monitoring. All children were in the supine position and fed a pH 7 diet infused continuously with a nasogastric tube; 15 children were under pancuronium. An abnormal gastroesophageal reflux was found in 4 children, associated with a benign esophagitis in 2. A benign esophagitis without gastroesophageal reflux was found in 3 cases. One child had a peptic ulcer of the bulb without gastroesophageal reflux nor oesophagitis. 21 children had no abnormality. Only one of the 15 children under pancuronium had an abnormal gastroesophageal reflux. We conclude that in intubated children fed continuously with a nasogastric tube, gastroesophageal reflux is unfrequent and, when present, appears to have little consequences.

Enteral Nutrition↗
PubMed1988

[Benign tumors of the spine in the adolescent. Surgical considerations apropos of 4 cases].

About 4 observations of benign tumours of the spine of the adolescent, we have studied the surgical aspect of the treatment of these lesion. The choice of the surgical approach is fundamental in view of the necessity of a complete exeresis, which implies techniques of spinal reconstruction and stabilization. Those problems are illustrated by: 2 cases of aneurysmal cyst, 1 case of eosinophilic granuloma, and 1 case of osteochondroma.

Adolescent↗
PubMed1988

[Modalities of the care of acute non-severe infantile diarrhea as a function of the place of care. Prospective study during a winter epidemic].

Seventeen pediatricians and 34 general practitioners (GP) randomly selected in the closest area around Edouard-Herriot hospital (Lyon, France) were questioned regarding socio-economic status of families of infants who were treated for non severe acute diarrhea (loss of weight less than 10% of the initial body weight, no dehydration), and gave a copy of their prescription. During the same period, information was collected on outpatients as well as hospitalized cases of non severe acute diarrhea. Results show that in 3 months, GPs treated approximately 500 cases of non severe acute diarrhea, pediatricians 230 and the hospital 64. Oral rehydration was prescribed in 16% of diarrhea treated by GPs and 50% of those treated by pediatricians. The socio-economic status of families treated by pediatricians differed widely from those treated by GPs as well as those cared for in hospital. Vomiting as an argument for admission was found in 55% of referrals.

Acute Disease↗
PubMed1987

Identification and characterization of conserved and variable regions in the neutralization VP2 gene of bluetongue virus.

To determine the extent and nature of genetic variation among three serotypes of bluetongue virus (BTV), the nucleotide sequences of the outer capsid gene (L2) encoding the neutralization antigen (VP2) of serotypes BTV-11 and BTV-17 were determined. The predicted amino acids of the two proteins were then compared with that of BTV-10 (M. A. Purdy, H. Ghiasi, C. D. Rao, and P. Roy, 1985, J. Virol. 55, 826-830). The results indicated that although the three genes were closely related (70% conserved), the variation is extensive in comparison to the gene encoding the inner capsid polypeptide, VP3, which is 98% conserved in these serotypes (H. Ghiasi, M. A. Purdy, and P. Roy, 1985, Virus Res. 3, 181-190). Several regions with clustered amino acid substitution were identified. Based on predicted secondary structure and hydrophilicity, these variable regions represent potential antigenic sites. In contrast to the variable regions, other sequences and the overall VP2 structure (including cysteine, proline, and glycine residues) were highly conserved.

Amino Acid Sequence↗
PubMed1987

Production and characterization of the neutralization antigen VP2 of bluetongue virus serotype 10 using a baculovirus expression vector.

DNA representing RNA segment 2 of bluetongue virus (BTV) serotype 10, corresponding to the gene that codes for the BTV neutralization antigen VP2, has been inserted into a baculovirus transfer vector in lieu of the 5' coding region of the polyhedrin gene of Autographa californica nuclear polyhedrosis virus (AcNPV). After cotransfection of Spodoptera frugiperda cells with wild-type AcNPV DNA in the presence of the derived recombinant transfer vector DNA, polyhedrin-negative recombinant baculoviruses were recovered. When S. frugiperda cells were infected with one of these recombinant viruses, a protein that was similar in size and antigenic properties to the BTV VP2 protein was synthesized. Antibodies raised in mice or rabbits to the baculovirus expressed VP2 protein neutralized the infectivity of BTV-10 virus and to lesser extents BTV serotype 11 and 17 viruses but not BTV-13 virus.

Animals↗
PubMed1987

Variation in the bluetongue virus neutralization protein VP2.

To determine the extent and nature of the antigenic variation of four U.S.A. serotypes of bluetongue virus (BTV), the complete nucleotide sequence was determined for cDNA clones representing the L2 dsRNA of BTV serotype 13, the gene that codes for the outer capsid neutralization antigen (VP2). The predicted amino acid sequence of the protein was compared with the VP2 sequences of the U.S.A. serotypes of BTV-10, BTV-11 and BTV-17. Diagon comparisons, hydropathic plots and analyses of potential secondary structure of the four proteins indicated that all four VP2 proteins were structurally similar. However, the VP2 protein of BTV-13 was found to exhibit only 40% homology with the VP2 species of the other three viruses. The comparative sequence data indicated that there were regions of the proteins with greater variability than other regions, as expected for proteins that vary antigenically but are structurally similar.

Amino Acid Sequence↗
PubMed1987

Expression of bluetongue virus group-specific antigen VP3 in insect cells by a baculovirus vector: its use for the detection of bluetongue virus antibodies.

DNA representing RNA segment 3 of bluetongue virus (BTV) serotype 17, corresponding to the gene that codes for a group-specific antigen VP3, has been inserted into a baculovirus transfer vector in lieu of the 5' coding region of the polyhedrin gene of Autographa californica nuclear polyhedrosis virus (AcNPV). After cotransfection of Spodoptera frugiperda cells with wild-type AcNPV DNA in the presence of the derived recombinant transfer vector DNA, polyhedrin-negative recombinant baculoviruses were recovered. When S. frugiperda cells were infected with one of these recombinant viruses, a protein that was similar in size and antigenic properties to the BTV VP3 protein was synthesized. Antibodies raised in mice or rabbits to the baculovirus-expressed VP3 protein immunoprecipitated the VP3 protein of BTV-17 as well as that of BTV-10. The expressed antigen reacted with antisera representing four U.S.A. BTV serotypes in an indirect ELISA test.

Animals↗
PubMed1987

Conformational analysis of pepstatin and related renin inhibitors by 400 MHz 1H n.m.r. spectroscopy.

The conformational behaviour of pepstatin (Iva-Val-Val-Sta-Ala-Sta) and of two derived renin inhibitors, Boc-Phe-Nle-Sta-Ala-Sta-OMe, 1, and Boc-Phe-Nle-X-Ala-Sta-OMe, 2 (X = -NH-CH(iPr)-CHOH-CH2-CO-) was assessed in DMSO-d6 at various temperatures and in deuteriopyridine at -35 degrees. Complete assignment of almost all proton signals was achieved by 2D COSY, 2D NOESY and selective NOE experiments. The three compounds show similar extended conformations in both solvents, with the hydrophobic lateral chains extending away from the peptide backbone. In the case of pepstatin the solvated conformation is closely related to the structure found in the crystal of the pepstatin-Rhizopus chinensis complex. Strong NOE effects and precise determination of vicinal coupling constants show the lack of large structural differences between 1 and 2 at the level of the internal Sta or X residues, which are assumed to interact with the aspartyl residues of the renin active-site. This suggests that the 100-fold lower inhibitory potency of 2 is mainly due to unfavorable close contacts of the beta-branched residue X with constituent amino acids of the enzyme.

Dimethyl Sulfoxide↗