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N Valero

Publications and source records attributed to N Valero.

8 recordsLinked to original sources
PubMed2001

High intensity light increases olfactory bulb melatonin in Venezuelan equine encephalitis virus infection.

In mice infected with the Venezuelan equine encephalomyelitis (VEE) virus and exposed to high intensity light (2500 lux) with a 12 h light: 12 h dark photoperiod, a significant increase in the levels of melatonin in the olfactory bulb was observed. The significance of these findings deserves further studies to understand the mechanisms involved in this effect since the olfactory bulbs have been proposed as first portal for VEE virus entry into the CNS. The increase in melatonin content could represent one of the mechanisms of defense against the viral attack.

Animals↗
PubMed2001

Melatonin treatment enhances the efficiency of mice immunization with Venezuelan equine encephalomyelitis virus TC-83.

To determine whether treatment with melatonin (MLT) improves the efficiency of immunization against Venezuelan equine encephalomyelitis (VEE) virus, mice were vaccinated with TC-83 VEE virus and treated daily with MLT (1 or 5 mg/kg) starting 3 days before immunization, until 10 days after. IgM antibody titers were determined at days 7, 14, and 21 post-immunization. IL-10 levels were assayed at day 14 postvaccination. Treatment with MLT increased antibody titers 14 days after the immunization. IL-10 levels also increased with MLT treatment (1 and 5 mg/kg). Mice were challenged with live VEE virus at day 21 postimmunization, and viral titers were plaque assayed in chicken embryo fibroblasts 4 days after the infection. Following this challenge brain virus levels were significantly reduced. The results suggest that MLT treatment enhances the efficiency of mice immunization against VEE virus.

Adjuvants, Immunologic↗
PubMed2001

[Evaluation of immunity against Venezuelan equine encephalitis virus and dengue in the human population of San Carlos, the Almirante Padilla Island Municipality, Zulia State, Venezuela. 1996].

The Insular Municipality of Almirante Padilla, historically, has been affected by Venezuelan Equine Encephalitis (VEE) epidemics, that have occurred cyclically in the Paez, Mara and Almirante Padilla Municipalities of the State of Zulia. During the last epidemic outbreak (1995), the studies reported a great number of cases of VEE in humans, based on epidemiologic-clinical diagnosis; occupying this municipality, the first place in the attack rate by the virus. At the same time, Dengue has been defined as an endemic illness affecting different regions, whose etiologic agent has previously circulated in the studied zone. In order to evaluate the immunity acquired against these viruses, a serological study was conducted in San Carlos Island. Two hundred and ten blood samples were obtained at random, among individuals of an age range between < 1 and 69 years, with and without antecedents of viral illness symptomatology at the moment of the epidemic outbreak, occurred in 1995. The samples were classified according to sex and age, and analyzed through the test of ELISA for specific IgG antibodies against the VEE and Dengue viruses. From the total of the samples processed, 116 (55.2%) were positive for VEE, affecting uniformly all age-groups with a slight masculine predominance. Likewise, 88 cases (41.9%) were determined positive for Dengue virus, affecting mainly the group ranging from 10 to 19 years. These results let us suggest that the epidemic outbreak occurred in 1995 at the Almirante Padilla Insular Municipality, had a double nature with both viruses being involved in the etiology of febrile cases.

Adolescent↗
PubMed2001

In mice the efficiency of immunization with Venezuelan Equine Encephalomyelitis virus TC-83 is transiently increased by dehydroepiandrosterone.

To determine whether treatment with dehydroepiandrosterone (DHEA) improves the efficiency of immunization against the Venezuelan Equine Encephalomyelitis (VEE) virus, mice were vaccinated with the TC-83 VEE virus. DHEA (10 mg/kg) was administered in a single dose, 4 hours before vaccination. IgM antibody titers were determined at days 7, 14 and 21 post-immunization. Treatment with DHEA increased antibody titers at day 14 after immunization. Mice were challenged with live VEE virus at day 21, and viral titers were plaque assayed in chicken embryo fibroblasts from days 2 to 5 post-infection. After the challenge, viremia decreased on day 2 and brain virus levels were reduced at day 4 in mice treated with DHEA. These results suggest that DHEA treatment could enhance the efficiency of immunization against VEE virus in mice.

Adjuvants, Immunologic↗
PubMed2001

[Viral agents in patients with infectious processes of the central nervous system].

Local statistics report a great number of cases of neurological diseases of unidentified cause. The purpose of this research was to determine the presence of viral agents in patients with affection of the central nervous system, in Zulia State, Venezuela. In different health centers throughout the state, we collected 129 randomized samples of cerebrospinal fluid (CSF) and serum from patients ranging from 1 day to 41 years of age, showing symptoms of CNS disease and whose bacteriological test resulted negative. The serum/CSF albumin ratio was determined to exclude contaminated CSF samples, thus 54 optimal samples were obtained for the research. We determined serum IgM and CSF IgG specific for Venezuelan equine encephalomyelitis (VEE), Herpes simplex (HSV), Epstein Barr (EBV), Dengue, Rubella and Measles virus, through ELISA and indirect immunofluorescence techniques. Of the 54 samples studied, 33 (61.11%) were positive. %). The etiological agents implicated were VEE 14 cases (42.42%); HSV 11 cases (33.33%); EBV 5 cases (15.15%) and Dengue 3 cases (9.09%). We did not detect Rubella o Measles. Regarding the age distribution, the most affected group was that of children under 12 (83.34%). We analyzed the clinical manifestations and the CSF characteristics and did not find differences suggestive of an specific etiological diagnosis, even though certain signs could be considered early indications of CNS alterations due to viral causes. Our study shows that a large percentage of CNS affections of unknown etiology are produced by viral agents, indicating that in our region, most of this cases are not registered.

Antibodies, Viral↗
PubMedDate not supplied

Melatonin prolongs survival of immunodepressed mice infected with the Venezuelan equine encephalomyelitis virus.

Male albino mice immunodepressed after the injection of dexamethasone (DEX) were inoculated intraperitoneally with the Guajira strain of Venezuelan equine encephalomyelitis (VEE) virus. Melatonin (MLT) was administered daily, at a dose of 500 micrograms/kg bodyweight, for 3 days before virus inoculation and 10 days after. Serum levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2) were determined in all the experimental groups (control, DEX, DEX + MLT, DEX + VEE, DEX + VEE + MLT, VEE and MLT). At day 6 after the virus inoculation, the survival rate was significantly increased from 0% in group DEX + VEE to 32.5% in the group of immunodepressed infected mice treated with MLT (DEX + VEE + MLT). By day 10 a survival rate of 10% was found in group DEX + VEE + MLT and 0% in group VEE. No alterations in IL-2 serum levels were observed. MLT increased GM-CSF in control and in DEX-treated mice. In the VEE virus-infected mice treated with DEX, serum levels of GM-CSF increased progressively from day 1 to 5 postinoculation. In contrast, the levels of GM-CSF in infected immunodepressed mice treated with MLT decreased significantly from day 1 to 5 postinoculation. At day 5 after viral inoculation, no differences were detected in the cerebral viral titres in groups VEE, DEX + VEE and DEX + MLT + VEE. These results show that MLT does not inhibit VEE viral replication in the brain of immunodepressed mice.

Adjuvants, Immunologic↗