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R A Guerrero

Publications and source records attributed to R A Guerrero.

8 recordsLinked to original sources
PubMed2006

A new species of Hypocristata (Nematoda, Trichostrongyuna, Heligmosomoidea) a parasite of Sigmodon hispidus (Cricetidae, Sigmodontinae) from Venezuela.

Description of Hypocristata tercera n. sp. (Heligmonellidae, Nippostrongylinae) a parasite of the small intestine of Sigmodon hispidus (Rodent, Sigmodontinae) from Venezuela. Two other species were described in the genus, both from Colombia and parasitic in Sigmodontinae. H. thomosomysi Durette-Desset, 1970, a parasite of Thomasomys sp. has about the same number of cuticular ridges at mid-body but differs by ridges having chitinoid struts, a caudal bursa pattern of type 2-2-1 (vs 1-3-1). H. anguillula Durette-Desset, 1970, a parasite of Sigmodontomys alfari (= Nectomys alfari) has the same caudal bursa pattern (type 1-3-1) but differs by the presence of ridges at mid-body in both sexes (absent at that level in H. tercera) and by ridges having chitinoid struts in female. This is the first report of the genus Hypocristata Durette-Desset, 1971 in Venezuela and in the genus Sigmodon (Sigmodontinae).

Animals↗
PubMed2001

Recombinant Norwalk virus-like particles administered intranasally to mice induce systemic and mucosal (fecal and vaginal) immune responses.

Recombinant Norwalk virus-like particles (rNV VLPs) were administered to BALB/c mice by the intranasal (i.n.) route to evaluate the induction of mucosal antibody responses. The results were compared to systemic and mucosal responses observed in new and previous studies (J. M. Ball, M. E. Hardy, R. L. Atmar, M. E. Connor, and M. K. Estes, J. Virol. 72:1345-1353, 1998) after oral administration of rNV VLPs. Immunizations were given in the presence or absence of a mucosal adjuvant, mutant Escherichia coli heat-labile toxin LT(R192G). rNV-specific immunoglobulin G (IgG) and fecal IgA were evaluated by enzyme-linked immunosorbent assay. The i.n. delivery of rNV VLPs was more effective than the oral route at inducing serum IgG and fecal IgA responses to low doses of rNV particles. Vaginal responses of female mice given VLPs by the i.n. and oral routes were also examined. All mice that received two immunizations with low doses i.n. (10 or 25 microg) of rNV VLPs and the majority of mice that received two high doses orally (200 microg) in the absence of adjuvant had rNV-specific serum IgG, fecal, and vaginal responses. Additional experiments evaluated whether rNV VLPs can function as a mucosal adjuvant by evaluating the immune responses to two soluble proteins, keyhole limpet hemocyanin and chicken egg albumin. Under the conditions tested, rNV VLPs did not enhance the serum IgG or fecal IgA response to these soluble proteins when coadministered by the i.n. or oral route. Low doses of nonreplicating rNV VLPs are immunogenic when administered i.n. in the absence of adjuvant, and addition of adjuvant enhanced the magnitude and duration of these responses. Recombinant NV VLPs represent a candidate mucosal vaccine for NV infections in humans.

Adjuvants, Immunologic↗
PubMed2000

Predictors of tuberculosis transmission in prisons: an analysis using conventional and molecular methods.

OBJECTIVE: To determine the tuberculosis (TB) transmission patterns within the prison system in Catalonia, conventional epidemiological techniques were combined with DNA fingerprinting of Mycobacterium tuberculosis. METHODS: IS6110- and polymorphic GC-rich repeat sequence (PGRS)-based restriction fragment length polymorphism (RFLP) were combined with epidemiological studies to assess the relatedness of isolates from all patients with confirmed TB at five prisons in the province of Barcelona (Catalonia, Spain), between 1 July 1994 and 31 December 1996. Risk factors for transmission were analysed to a logistic regression. The extent of drug-resistant TB was also assessed. RESULTS: The incidence of TB during the study period was 2775 cases per 100,000 inmate years. Of the 247 culture-positive cases, 126 (51%) appeared to have active TB as a result of recent transmission. Using conventional epidemiological methods, 14 active chains of transmission were identified in prison involving 65 isolates (52% of clustered patients). A lengthy history of imprisonment [odds ratio (OR) 2.8, 95% confidence interval (CI) 1.52-5.11] and pulmonary TB (OR 2.36, 95% CI 1.17-4.75) were independently associated with clustering. Low rates of both initial (2.9%) and acquired drug resistance (5.8%) were identified and there was no evidence of the transmission of drug-resistant TB. CONCLUSION: In the prison system studied, the recent transmission of TB contributes substantially to the overall incidence of the disease. Both lengthy incarcerations and delays in identifying inmates with pulmonary symptoms play a key role in this recent transmission. Directly observed therapy (DOT) is a critical control strategy for reducing the emergence of drug resistance and for avoiding the transmission of resistant organisms.

Adolescent↗
PubMed2000

Norwalk virus vaccines: challenges and progress.

Human caliciviruses (HuCVs) are the major cause of outbreaks of acute nonbacterial gastroenteritis throughout the world. An increasing recognition of the clinical significance of these viruses as human pathogens causing foodborne and waterborne disease indicates that an effective vaccine would be useful. This article reviews the current challenges that exist for the development of a vaccine for the HuCVs as well as the status of development of a candidate vaccine. HuCVs are viruses that exhibit a restricted tropism for infection of the gastrointestinal tract of humans, and a volunteer model of infection and disease is available. As pathogens with a restricted host range, the HuCVs are excellent models for understanding the mechanisms that mediate and regulate viral infection of the gastrointestinal tract and mucosal immunity in humans.

Caliciviridae Infections↗
PubMed1999

Recombinant Norwalk virus-like particles given orally to volunteers: phase I study.

BACKGROUND & AIMS: Norwalk virus (NV) is a major cause of epidemic gastroenteritis. The NV capsid is composed of a single protein that forms recombinant (rNV) virus-like particles (VLPs). In mice, these VLPs are immunogenic when administered orally without adjuvant, and they elicit serum immunoglobulin (Ig) G and intestinal IgA responses. The aim of this study was to evaluate the safety and immunogenicity of rNV VLPs in healthy volunteers. METHODS: Twenty antibody-positive adults were orally administered rNV VLPs in sterile Milli-Q water on days 1 and 21. Vaccine safety and serum rNV-specific total and subclass IgG and IgA antibody responses were monitored. The immune response induced by the VLPs was compared with the response elicited by replicating virus. RESULTS: No side effects were observed or reported by the volunteers. Serum IgG responses to rNV VLPs were dose-dependent, and all vaccinees given 250 microgram of rNV VLPs responded with >/=4-fold increases in serum IgG titers. Most of the volunteers (83%; 15 of 18) responded after the first rNV VLP dose and showed no increase in serum IgG titer after the second dose. CONCLUSIONS: Orally administered rNV VLPs are safe and immunogenic in healthy adults when administered without adjuvant and are useful to test the mucosal delivery of immunogens.

Administration, Oral↗
PubMed1995

[Characteristics of AIDS cases detected at a prison in Barcelona (1991-1993)].

OBJECTIVE: To describe the cases of AIDS detected in a Barcelona prison. DESIGN: A prospective study. SETTING: A penitentiary for men in Barcelona. PATIENTS: All those inmates who had AIDS or were diagnosed with the illness during their stay in prison during the 36 months between 1/1/1991 and 31/12/93. RESULTS: 220 cases of AIDS (91.7% PVDA), 60% of which were diagnosed in prison. The PVDA were younger (p < 0.0001). There were a greater number of Spaniards among the UDVP (p < 0.01) and among those with tattoos (p < 0.001). The first manifestation of the disease in 53% of the cases was extrapulmonary Tuberculosis. CONCLUSIONS: Prisons are key places in the prevention and monitoring of HIV infection. The use of care programmes, including maintenance programmes using Methadone, for drug-dependent patients are recommended. The continuation of programmes tracking Tuberculosis, the main illness related to HIV infection in prison, is also recommended.

Acquired Immunodeficiency Syndrome↗