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Biomedical subjects

P Roy

Publications and source records attributed to P Roy.

At least 145 records · Page 8Linked to original sources
PubMed1997

Baculovirus-expressed nonstructural protein NS2 of bluetongue virus induces a cytotoxic T-cell response in mice which affords partial protection.

Virus-specific cytotoxic T lymphocytes were generated in two strains of mice (BALB/c and CBA/Ca) against baculovirus recombinant proteins (minor and nonstructural) derived from bluetongue virus serotype 10. Immunization of mice with recombinant baculovirus insect cell extracts expressing the nonstructural protein NS2 (Bac-NS2) conferred partial protection against infection with vaccinia virus expressing the NS2 protein. This protective immunity was mediated by CD8+ cells. In contrast, no protection was observed when mice were immunized with similarly expressed Bac-NS1 or -NS3 or the virion minor structural proteins (Bac-VP1, -VP4, or -VP6). Furthermore, the in vitro cytotoxicity activity of T cells derived from immunized animals did not correlate to the protective efficacy of baculovirus recombinant proteins. The implications of this work with regard to the design of noninfectious subunit vaccines are discussed.

Animals↗
PubMed1997

Serologic markers in early stages of African horse sickness virus infection.

Fifteen horses were experimentally infected with African horse sickness virus (AHSV) serotype 4. To learn more about the time course of production and specificity of AHSV-specific antibodies, sera were analyzed by immunoblot analysis. Only animals that survived for more than 9 days were able to develop a humoral immune response detectable by immunoblotting. The earliest serological markers corresponded mainly to VP5, VP6, and NS2 and to a lesser extent to VP3, NS1, and NS3. Neutralizing antibodies to VP2 were not detected by immunoblotting, suggesting that they are mostly conformation dependent. VP7-specific antibodies were detected later in infection. These results make NS2 and VP6 the most attractive candidates for the rapid diagnosis of the infection.

African Horse Sickness↗
PubMed1997

Bluetongue virus VP6 protein binds ATP and exhibits an RNA-dependent ATPase function and a helicase activity that catalyze the unwinding of double-stranded RNA substrates.

RNA-dependent ATPase and helicase activities have been identified associated with the purified VP6 protein of bluetongue virus, a member of the Orbivirus genus of double-stranded RNA (dsRNA; Reoviridae family) viruses. In addition, the protein has an ATP binding activity. RNA unwinding of duplexes occurred with both 3' and 5' overhang templates, as well as with blunt-ended dsRNA, an activity not previously identified in other viral helicases. Although little sequence similarity to other helicases was detected, certain similarities to motifs commonly attributed to such proteins were identified.

Adenosine Triphosphatases↗
PubMed1997

Does maternal employment augment spending for children's health care? A test from Haryana, India.

Evidence that women's employment and earnings foster increased allocations of household resources to children's well-being have led to advocacy of investment in women's employment as a method for targeting the social benefits of enhanced economic opportunity. Work and associated earnings are hypothesized to empower women, who can then exercise their individual preferences for spending on child well-being as well as influence household spending patterns. This paper presents results from a small detailed household and community study of maternal employment and child health in northern India (one of six studies in a research network), which sought to show that such effects did indeed occur and that they could be linked to work characteristics. Careful analysis of employment and earnings showed that they are multidimensional and highly variable over occupations and seasons. Contrary to expectations, spending on health care for children's illness episodes was negatively associated with maternal employment and earnings variables in econometric analysis. The expected individual effects on women of work and earnings, if they did occur, were not sufficient to alter the general spending pattern. We conclude that the attributes of work as well as the social and cultural environment are important mediators of such effects, suggesting a confluence of 'individual' and 'collective' behavioural determinants meeting in the locus of the household.

Adult↗
PubMed1997

Interethnic marriage: identifying the second generation in Australia.

"Studies in Australia show that an increasing proportion of the population have ancestors from more than one country. Evidence regarding differences in the marriage patterns of first and second generation migrants has been restricted in scope as published marriage registration data includes only birthplace of partners. Marriage registration records include information about the birthplace of parents of partners, but is available only through specially produced tabulations. Changes in the census for 1986 and 1991 make it possible to identify the second generation in households, and this article examines the use of census data as an alternative to marriage registration records in tracing changes in intermarriage patterns and differences between urban and rural areas."

Australia↗
PubMed1997

[Peroperative radiotherapy in the conservative treatment of infiltrating bladder cancers].

OBJECTIVE: Descriptive analysis of an intraoperative radiotherapy protocol (IOR) in the context of conservative management of invasive bladder cancer. METHOD: From November 1988 to September 1994, 24 patients with invasive bladder carcinoma (20 T2, 3 T3) were included in this protocol consisting of: transurethral resection (TUR), neoadjuvant chemotherapy (M.V.C.) in 14 patients, external irradiation (x 18 MV: 48 Gy/24 F/5 weeks) with concomitant chemotherapy (cisplatin 30 mg/day-3 days-2 cycles during irradiation)-follow-up cystoscopy then surgery with IOR (E 9 MeV: 15 Gy). RESULTS: The global 3-year survival was 69%. An invasive intravesical relapse developed in 3 patients (1 salvaged by cystectomy) and a superficial relapse occurred in 1 patient. One patient developed pelvic lymph node progression and 7 developed distant metastases. The early and late toxicity was acceptable with 3 cases of ureteric necrosis or stenoses resolving after medical treatment. CONCLUSION: This series shows encouraging preliminary results. IOR appears to be a technique well adapted to lesions of the fixed portion of the bladder.

Adult↗
PubMed1997

Population-based study of the treatment and prognosis of carcinoma of the rectum.

BACKGROUND: Few population-based studies address the issue of treatment of carcinoma of the rectum (15 cm or less from the anal verge) both from surgical and epidemiological aspects. METHODS: Some 827 patients were analysed in the cancer registry of the Côte-d'Or (Burgundy, France) from 1976 to 1990 (493,931 inhabitants). RESULTS: Resection for cure increased from 57.2 per cent before 1981 to 77.0 per cent after 1985 (P < 0.001), and the proportion of Dukes A and B cases from 35.8 to 52.5 per cent (P < 0.001). Among patients resected for cure, continence-preserving resections were performed more frequently during the 1986-1990 period (48.0 per cent) than during the two previous 5-year periods (20.0 per cent; P < 0.001), more often in women, in the upper half of the ampulla and for tumours of less than 45 mm. The operative mortality rate after curative surgery decreased from 13.9 to 3.7 per cent (P < 0.001) between the first and the last period whereas the 5-year crude survival rate rose from 25.8 to 42.6 per cent (P < 0.001). Age, stage of disease and period of diagnosis were independent prognostic factors of death in a relative survival model. CONCLUSION: This study indicates that significant advances have been achieved at a population level in the treatment of rectal cancer in terms of diagnosis, continence-preserving procedures and survival.

Aged↗
PubMed1996

Molecular characterization of the segment 2 gene of epizootic hemorrhagic disease virus serotype 2: gene sequence and genetic diversity.

The complete nucleotide sequence of the gene encoding the major outer capsid protein VP2 from the Alberta isolate of epizootic hemorrhagic disease virus serotype 2 (EHDV-2) was determined. Complementary DNA (cDNA) corresponding to segment 2 was 3002 nucleotides in length with a single open reading frame that encoded a VP2 of 982 amino acids. Although the VP2 from EHDV-2 was only 34% homologous to the cognate protein from EHDV-1, their predicted hydropathic profiles were similar, suggesting that conservation of structure is important biologically to these capsid proteins. Sequence analysis of six North American EHDV-2 field isolates showed a high degree of comparative genetic identity (> 97%). Phylogenetic profiles constructed suggest that regionalization of the viruses within the North American continent has contributed to the genetic diversity.

Amino Acid Sequence↗
PubMed1996

The solution structure of the bovine leukaemia virus matrix protein and similarity with lentiviral matrix proteins.

In the mature virion, retroviral matrix proteins are found in association with the inner face of the viral membrane. They play a critical role in determining the morphogenesis of virus assembly. We have determined the three-dimensional solution structure of the bovine leukaemia virus (BLV) matrix protein by heteronuclear nuclear magnetic resonance. The protein contains four principal helices that are joined by short, partially structured loops. Despite no sequence similarity with the lentiviruses, the structure shows an intriguing homology with the equivalent protein from the human and simian immunodeficiency viruses. A root-mean-square deviation of 3.78 angstrom is observed over the backbone atoms of 36 equivalent helical positions. The similarity implies a possible common assembly unit for the matrix proteins of type C retroviruses.

Amino Acid Sequence↗
PubMed1996

Immunization with VP2 is sufficient for protection against lethal challenge with African horsesickness virus Type 4.

Horses were immunized by inoculation with a vaccinia construct containing a full-length cDNA corresponding to the L2 gene segment of African horsesickness virus type 4(AHSV-4). All immunized horses developed serum neutralizing antibodies prior to challenge with virulent AHSV-4. No ELISA-reactive antibodies were present prior to challenge. A group of four seronegative control horses died after developing clinical signs and lesions typical of the pulmonary form of African horsesickness while the immunized horses were clinically normal. Increases in serum neutralizing and ELISA-reactive antibody titers following challenge indicate that at least some replication of challenge virus occurred in immunized horses. These results demonstrate that AHSV VP2 alone is sufficient to induce a protective immune response in horses and indicate the usefulness of ELISA-reactive antibodies for differentiation of vaccinated and naturally exposed horses.

African Horse Sickness↗
PubMed1996

A new form of particulate single and multiple immunogen delivery system based on recombinant bluetongue virus-derived tubules.

The development of particular vector systems for the presentation of immunogenic epitopes provides a powerful approach for the delivery of antigens. These include the core-like particles formed by recombinant bluetongue virus (BTV) capsid proteins VP3 and VP7 synthesized in insect cells by recombinant baculoviruses. Previously we have reported localization of an antigenic site on the surface of tubular structures formed by the nonstructural protein NS1 of BTV, and their potential use for epitope presentation. In this study foreign sequences ranging form 44 to 116 aa in length and representing 44 aa sequence from Clostridium difficile toxin A, 48 aa of the hepatitis B virus preS2 region, and the whole of bovine leukemia virus p15 protein were inserted at the C-terminus of BTV-10 NS1. The chimeric NS1 genes were expressed using recombinant baculoviruses and the ability of the mutated NS1 proteins to form tubules was investigated. All chimeric constructs formed tubular structures which carried the foreign antigenic sequences exposed on the surface of the tubules and were highly immunogenic. When Sf cells were coinfected with three recombinant baculoviruses expressing chimeric NS1 proteins with different epitopes, their simultaneous assembly into the same tubule was demonstrated. This observation opens up the possibility of using recombinant NS1 tubules as carriers for the delivery of multiple epitopes.

Animals↗
PubMed1996

Orbivirus structure and assembly.

Orbiviruses (Reoviridae family) are complex nonenveloped RNA viruses with seven structural proteins and a RNA genome consisting of 10 variously sized double-stranded RNA segments. Significant advances in orbivirus research have been made in recent years through the use of gene manipulation techniques coupled with the baculovirus expression system. Several orbivirus proteins have yielded to crystallization and X-ray crystallographic structure determination and, when combined with the three-dimensional image reconstruction of virion particles and cores obtained by cryoelectron microscopy, considerable insight has been gained into the intricate organization and topography of the individual viral components. Formal identification of the sites of interaction has been obtained through protein-protein interaction studies on the components of the virion particle, including those that are involved in capsid assembly. Finally, a beginning of the understanding of the sequence of assembly events has also been obtained.

Animals↗
PubMed1996

Combined curative radiation therapy alone in (T1) T2-3 rectal adenocarcinoma: a pilot study of 29 patients.

AIM: Analysis of a pilot study including 29 consecutive patients with high surgical risk or refusal of colostomy treated with radiation therapy alone with curative intent. PATIENTS: Between 1986 and 1992, 29 patients were treated for infiltrating adenocarcinoma of the rectum. Median age was 72 years. Transrectal ultrasound staging was used in 24 patients (T1, 2; T2, 14; T3, 13; N0, 23; N1, 6). In 20 patients the lower border of the tumor was at 5 cm or less from the anal verge and in 19 patients the diameter exceeded 3 cm. CEA was elevated in seven cases. TREATMENT: Contact X-ray (50 kV) was given first (70 Gy/3 fractions). External beam radiation therapy used a three-field technique in the prone position. Accelerated schedule (39 Gy/13 fractions/17 days) with a concomitant boost "field within the field' (4 Gy/4 fractions). Six weeks later an iridium-192 implant was performed in 21 (20 Gy/22 h). RESULTS: Median follow-up time was 46 months. Overall and specific survival at 5 years was 68% (SE = 0.09) and 76% (SE = 0.08). Local control was obtained in 21/29 patients (72%). There was one grade 2 rectal bleeding and five grade 2 rectal necroses. The overall tolerance was good in these frail patients. DISCUSSION: For T2. T3 or T1 > 3 cm diameter rectal adenocarcinoma, where contact X-ray alone is not recommended, a combined treatment with radiation therapy alone is able to give good local control with acceptable toxicity. This treatment should be restricted to inoperable patients.

Adenocarcinoma↗