Melatonin decreases brain apoptosis, oxidative stress, and CD200 expression and increased survival rate in mice infected by Venezuelan equine encephalitis virus.

Background: Pro-inflammatory and oxidative events during brain Venezuelan equine encephalitis virus infection could lead to apoptosis and induce anti-inflammatory responses (increased expression of CD200). The aim of this study was to determine the effect of melatonin on brain apoptosis, oxidative stress, and CD200 molecule in mice and neuroblastoma cultures infected by Venezuelan equine encephalitis virus.

Methods: Mice were infected with 10 median lethal doses (LD50) of Venezuelan equine encephalitis virus, treated with melatonin (500 µg/kg bw; three days before infection and during all experimental time) and sacrificed on days 1, 3, and 5 postinfection.

Distribution of Dengue Virus Types 1 and 4 in Blood Components from Infected Blood Donors from Puerto Rico.

Background: Dengue is a mosquito-borne viral disease caused by the four dengue viruses (DENV-1 to 4) that can also be transmitted by blood transfusion and organ transplantation. The distribution of DENV in the components of blood from infected donors is poorly understood.

Methods: We used an in-house TaqMan qRT-PCR assay to test residual samples of plasma, cellular components of whole blood (CCWB), serum and clot specimens from the same collection from blood donors who were DENV-RNA-reactive in a parallel blood safety study.

Increased cytokine/chemokines in serum from asthmatic and non-asthmatic patients with viral respiratory infection.

Background: Respiratory viral infections can induce different cytokine/chemokine profiles in lung tissues and have a significant influence on patients with asthma. There is little information about the systemic cytokine status in viral respiratory-infected asthmatic patients compared with non-asthmatic patients.

Objectives: The aim of this study was to determine changes in circulating cytokines (IL-1β, TNF-α, IL-4, IL-5) and chemokines (MCP1: monocyte chemoattractant protein-1 and RANTES: regulated on activation normal T cell expressed and secreted) in patients with an asthmatic versus a non-asthmatic background with respiratory syncytial virus, parainfluenza virus or adenovirus respiratory infection.

Phylogenetic analysis of dengue virus types 1 and 4 circulating in Puerto Rico and Key West, Florida, during 2010 epidemics.

We describe sequences of six strains of dengue virus (DENV): three DENV-1 isolates and two DENV-4 isolates from Puerto Rico, and a DENV-1 strain from Key West, Florida, obtained from blood donors during 2010 epidemics. Phylogenetic analysis revealed that the Puerto Rico DENV-1 strains constitute a new lineage within genotype V different from those that circulated in Puerto Rico during the past two decades. The newer Puerto Rico DENV-1 strains associated with strains from the Caribbean and South America.

Respiratory syncytial virus infection increases regulated on activation normal T cell expressed and secreted and monocyte chemotactic protein 1 levels in serum of patients with asthma and in human monocyte cultures.

Background: Respiratory syncytial virus (RSV) infection is associated to episodic exacerbations of asthma involving alveolar macrophages and chemokine production.

Objective: The aim of this study was to determine the circulating levels of monocyte chemotactic protein 1 (MCP-1), regulated on activation normal T cell expressed and secreted (RANTES), and substance P (SP) in patients with and without asthma with acute respiratory RSV infection and the chemokine profile in RSV- infected monocyte cultures from normal individuals and individuals with asthma.

Methods: In this regard, 31 adult patients with acute respiratory infection (15 patients with asthma) were studied.

Increment of interleukin 6, tumour necrosis factor alpha, nitric oxide, C-reactive protein and apoptosis in dengue.

This study evaluated the levels of TNFalpha, IL-6, IL-1beta, nitric oxide (NO), CRP, C3 and apoptosis in 36 patients with dengue fever (DF), 34 patients with dengue haemorrhagic fever (DHF) and in virus-infected monocyte cultures. IL-6, TNFalpha, NO (nitrites) and CRP levels were increased and C3 diminished in patients with DF and DHF. IL-6, TNFalpha, CPR and C3 values were associated with disease severity (DHF).

[Increase of interleukin-1 beta, gamma interferon and tumor necrosis factor alpha in serum and brain of mice infected with the Venezuelan Equine Encephalitis virus].

Considerable efforts have been directed to clarify the main protective and recovery mechanisms in acute viral infections and, the possible role of the cytokines involved in the primary immune response induced by an epizootic strain of the Venezuelan Equine Encephalitis (VEE) virus. This study examined the levels of TH1 cytokines Interleukin-2 (IL-2) and Interferon-gamma (IFN-gamma), TH2 cytokines Interleukin-4 (IL-4) and proinflammatory cytokines (IL-1beta, TNF-alpha) in serum and brain of mice infected with the VEE virus during different post infection periods. NMRI albino male mice infected with a suspension (10 DL50) of the Guajira strain of the VEE virus, and a control group (without infection) were used.

Antagonistic effect of luzindole in mice treated with melatonin during the infection with the venezuelan equine encephalomyelitis virus.

The effect of Luzindole (LZ) in mice treated with melatonin (MEL) during the infection with the Venezuelan equine encephalomyelitis (VEE) virus was examined. Melatonin (500 microg/Kg b.w.

Melatonin decreases nitric oxide production, inducible nitric oxide synthase expression and lipid peroxidation induced by Venezuelan encephalitis equine virus in neuroblastoma cell cultures.

Increased expression of inducible nitric oxide synthase has been shown in murine Venezuelan equine encephalitis (VEE) virus infection. In this experimental model, melatonin (MTL) treatment has shown to be beneficial. The aim of this study was to determine the effect of VEE virus on the nitric oxide (NO) production and lipid peroxidation in neuroblastoma cell cultures, and to investigate the role of MTL during cell-virus interaction.

In vitro, melatonin treatment decreases nitric oxide levels in murine splenocytes cultured with the venezuelan equine encephalomyelitis virus.

The purpose of this work was to determine the effect of melatonin on the nitric oxide levels in murine splenocytes cultured with the Venezuelan equine encephalomyelitis virus. After incubation, nitric oxide levels were measured by the diazotization assay. Those cultures with the Venezuelan equine encephalomyelitis virus increased nitric oxide levels.

Ultrastructural studies on dengue virus type 2 infection of cultured human monocytes.

Background: Early interaction of dengue virus and monocyte/macrophages could be an important feature for virus dissemination after its initial entry via the mosquito vector. Since ultrastructural analysis of this interaction has not been reported, dengue type 2 (DEN2) virus-infected human monocyte cultures were studied at 1, 2, 4 and 6 hours after infection.

Results: Typical dengue particles and fuzzy coated viral particles were 35 to 42 nm and 74 to 85 nm respectively.

[Immunity to flavivirus in Amerindian population of the Sierra de Perijá, Zulia state, Venezuela].

Little information is available about Flavivirus infection in amerindian populations in western Venezuela. On this account the activity and seroprevalence of these viruses were determined and the hypothesis concerning the existence of a sylvatic cycle, conditioning the infection transmission of these viruses in indigenous populations, was studied. For this, blood samples from Yukpas (n=144) and Barí (n=110) communities were collected, 35 (Yukpas=25 and Barí=10) of which were processed for viral isolation followed by RT-PCR.

Melatonin increases interleukin-1beta and decreases tumor necrosis factor alpha in the brain of mice infected with the Venezuelan equine encephalomyelitis virus.

The effect of melatonin (MLT) on the brain levels of tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in Venezuelan equine encephalomyelitis (VEE) virus infection was determined. Brain homogenates from mice inoculated with 10 LD50 of VEE virus, untreated or treated with 500 microg MLT/kg body weight were assayed by ELISA to measure the levels of TNF-alpha and IL-1beta. MLT was injected daily starting 3 days before and continuing to 7 days after virus inoculation.

Increased apoptosis and expression of tumor necrosis factor-alpha caused by infection of cultured human monocytes with dengue virus.

Dengue (DEN) virus is responsible for one of the most significant viral diseases in tropical countries. Monocytes/macrophages (Mo/Mphi) are the major target cells for DEN virus. To determine the effects of the interaction between DEN virus and Mo/Mphi, human monocyte cultures were infected with DEN virus type 2.

Short report: increased level of serum nitric oxide in patients with dengue.

Nitric oxide (NO) has been involved in several infectious diseases. Virus dengue is capable of inducing increased levels of NO when cocultured with human Kupffer and spleen cells. However, no reports describe the levels of NO in patients with dengue infection.

Melatonin induces changes to serum cytokines in mice infected with the Venezuelan equine encephalomyelitis virus.

We determined the influence of melatonin (MLT) on the induction of interleukin (IL)-2, IL-1 beta, IL-4, tumour necrosis factor-alpha (TNF-alpha) and gamma interferon (IFN-gamma) on mice infected with the Venezuelan equine encephalomyelitis (VEE) virus. Levels of IFN-gamma in the MLT-treated group were significantly increased (P < 0.001) when compared with the control non-infected group from day 1 to 6 post-infection (p.