Evaluacion de un conjugado antirrabico por titulacion en diferentes microscopios fluorescentes

En cinco laboratorios se tituló una partida de conjugado antirrábico para inmunofluoresCencia con microscopios de tres marcas distintas, equipados con diferentes accesorios. Los títulos obtenidos variaron entre < 1:4 y 1:64, dependiendo de los accesorios utilizados. Estos resultados ponen de relieve la necesidad de titular los conjugados en cada laboratorio. Se mencionam los inconvenientes que pueden ocasionar la distribución del reactivo diluido de acuerdo con el título obtenido por el productor, o mezclado con suspensiones de cerebro de ratones normales e infectados con virus rábico

The Effect of Epstein-Barr Virus Latent Membrane Protein 2 Expression on the Kinetics of Early B Cell Infection

Infection of human B cells with wild-type Epstein-Barr virus (EBV) in vitro leads to activation and proliferation that result in efficient production of lymphoblastoid cell lines (LCLs). Latent Membrane Protein 2 (LMP2) is expressed early after infection and previous research has suggested a possible role in this process. Therefore, we generated recombinant EBV with knockouts of either or both protein isoforms, LMP2A and LMP2B (Δ2A, Δ2B, Δ2A/Δ2B) to study the effect of LMP2 in early B cell infection. Infection of B cells with Δ2A and Δ2A/Δ2B viruses led to a marked decrease in activation and proliferation relative to wild-type (wt) viruses, and resulted in higher percentages of apoptotic B cells. Δ2B virus infection showed activation levels comparable to wt, but fewer numbers of proliferating B cells. Early B cell infection with wt, Δ2A and Δ2B viruses did not result in changes in latent gene expression, with the exception of elevated LMP2B transcript in Δ2A virus infection. Infection with Δ2A and Δ2B viruses did not affect viral latency, determined by changes in LMP1/Zebra expression following BCR stimulation. However, BCR stimulation of Δ2A/Δ2B cells resulted in decreased LMP1 expression, which suggests loss of stability in viral latency. Long-term outgrowth assays revealed that LMP2A, but not LMP2B, is critical for efficient long-term growth of B cells in vitro. The lowest levels of activation, proliferation, and LCL formation were observed when both isoforms were deleted. These results suggest that LMP2A appears to be critical for efficient activation, proliferation and survival of EBV-infected B cells at early times after infection, which impacts the efficient long-term growth of B cells in culture. In contrast, LMP2B did not appear to play a significant role in these processes, and long-term growth of infected B cells was not affected by the absence of this protein. © 2013 Wasil et al

Epstein–Barr virus serology and gastric cancer incidence and survival

Among 185 cases of gastric cancer and 200 controls in Linxian, China, Epstein–Barr virus (EBV) seropositivity was not associated with increased risk of gastric cancer. High EBV nuclear antigen titres were associated with longer survival in cardia cancer cases, possibly due to chance

Retrospective Investigation of an Influenza A/H1N1pdm Outbreak in an Italian Military Ship Cruising in the Mediterranean Sea, May-September 2009

BACKGROUND: Clinical surveillance may have underestimated the real extent of the spread of the new strain of influenza A/H1N1, which surfaced in April 2009 originating the first influenza pandemic of the 21(st) century. Here we report a serological investigation on an influenza A/H1N1pdm outbreak in an Italian military ship while cruising in the Mediterranean Sea (May 24-September 6, 2009). METHODS: The contemporary presence of HAI and CF antibodies was used to retrospectively estimate the extent of influenza A/H1N1pdm spread across the crew members (median age: 29 years). FINDINGS: During the cruise, 2 crew members fulfilled the surveillance case definition for influenza, but only one was laboratory confirmed by influenza A/H1N1pdm-specific RT-PCR; 52 reported acute respiratory illness (ARI) episodes, and 183 reported no ARI episodes. Overall, among the 211 crew member for whom a valid serological result was available, 39.3% tested seropositive for influenza A/H1N1pdm. The proportion of seropositives was significantly associated with more crowded living quarters and tended to be higher in those aged <40 and in those reporting ARI or suspected/confirmed influenza A/H1N1pdm compared to the asymptomatic individuals. No association was found with previous seasonal influenza vaccination. CONCLUSIONS: These findings underline the risk for rapid spread of novel strains of influenza A in confined environment, such as military ships, where crowding, rigorous working environment, physiologic stress occur. The high proportion of asymptomatic infections in this ship-borne outbreak supports the concept that serological surveillance in such semi-closed communities is essential to appreciate the real extent of influenza A/H1N1pdm spread and can constitute, since the early stage of a pandemic, an useful model to predict the public health impact of pandemic influenza and to establish proportionate and effective countermeasures

Development of real-time NASBA assays with molecular beacon detection to quantify mRNA coding for HHV-8 lytic and latent genes

BACKGROUND: Human herpesvirus-8 (HHV-8) is linked to the pathogenesis of Kaposi's sarcoma (KS), and the HHV-8 DNA load in peripheral blood mononuclear cells (PBMC) is associated with the clinical stage of KS. To examine the expression of HHV-8 in PBMC, four HHV-8 mRNA specific NASBA assays were developed METHODS: We have developed four quantitative nucleic acid sequence-based amplification assays (NASBA-QT) specifically to detect mRNA coding for ORF 73 (latency-associated nuclear antigen, LANA), vGCR (a membrane receptor), vBcl-2 (a viral inhibitor of apoptosis) and vIL-6 (a viral growth factor). The NASBA technique amplifies nucleic acids without thermocycling and mRNA can be amplified in a dsDNA background. A molecular beacon is used during amplification to enable real-time detection of the product. The assays were tested on PBMC samples of two AIDS-KS patients from the Amsterdam Cohort. RESULTS: For all four assays, the limit of detection (LOD) of 50 molecules and the limit of quantification (LOQ) of 100 molecules were determined using in vitro transcribed RNA. The linear dynamic range was 50 to 10(7) molecules of HHV-8 mRNA. We found HHV-8 mRNA expression in 9 out of the 10 tested samples. CONCLUSION: These real-time NASBA assays with beacon detection provide tools for further study of HHV-8 expression in patient material

Direct association between pharyngeal viral secretion and host cytokine response in severe pandemic influenza

<p>Abstract</p> <p>Background</p> <p>Severe disease caused by 2009 pandemic influenza A/H1N1virus is characterized by the presence of hypercytokinemia. The origin of the exacerbated cytokine response is unclear. As observed previously, uncontrolled influenza virus replication could strongly influence cytokine production. The objective of the present study was to evaluate the relationship between host cytokine responses and viral levels in pandemic influenza critically ill patients.</p> <p>Methods</p> <p>Twenty three patients admitted to the ICU with primary viral pneumonia were included in this study. A quantitative PCR based method targeting the M1 influenza gene was developed to quantify pharyngeal viral load. In addition, by using a multiplex based assay, we systematically evaluated host cytokine responses to the viral infection at admission to the ICU. Correlation studies between cytokine levels and viral load were done by calculating the Spearman correlation coefficient.</p> <p>Results</p> <p>Fifteen patients needed of intubation and ventilation, while eight did not need of mechanical ventilation during ICU hospitalization. Viral load in pharyngeal swabs was 300 fold higher in the group of patients with the worst respiratory condition at admission to the ICU. Pharyngeal viral load directly correlated with plasma levels of the pro-inflammatory cytokines IL-6, IL-12p70, IFN-γ, the chemotactic factors MIP-1β, GM-CSF, the angiogenic mediator VEGF and also of the immuno-modulatory cytokine IL-1ra (p < 0.05). Correlation studies demonstrated also the existence of a significant positive association between the levels of these mediators, evidencing that they are simultaneously regulated in response to the virus.</p> <p>Conclusions</p> <p>Severe respiratory disease caused by the 2009 pandemic influenza virus is characterized by the existence of a direct association between viral replication and host cytokine response, revealing a potential pathogenic link with the severe disease caused by other influenza subtypes such as H5N1.</p

Aspects of the encephalitis epidemic caused by arbovirus in the Ribeira Valley, S. Paulo, Brazil, during 1975-1978

In 1975, 1976, and 1977, arbovirus caused an encephalitis epidemic in the Ribeira Valley in the state of S. Paulo. The epidemic would peak when the temperature and pluvial levels were higher. From 1978 on the disease maintained low levels within a presumed endemic zone. The epidemic had swept from east to west and from east to southwest in a wave toward the neighboring coastal region. The mountain chain to the north and northwest acted as a barrier. It was only logical natural that the hypothesis that the etiological agent, arbovirus Rocio may have recently infected the human population be considered. Mosquitos must have transmitted the infection from birds and small mammals in nearby forests. Probable forms of transmission of arboviroses in the home are also discussed in this article as well as the fact that population groups that presented the worst forms of the disease were the very young, and the very old and those living in the worst conditions. The epidemiological perspective of the arboviroses is that it persists in this area because the area presents excellent conditions for the development of the etiological agent - reservoirs and biological vectors, with a continuous supply of susceptible people, migrants or tourists.Foi realizado estudo epidemiológico da encefalite por arbovirus na região do Vale do Ribeira, S. Paulo, Brasil. Uma epidemia da moléstia ocorreu em 1975, 1976 e 1977, com picos nas épocas de maior temperatura e pluviosidade. A partir de 1978 a moléstia manteve-se em níveis baixos numa presumível ende-micidade. A epidemia se deslocou em onda em direção leste-oeste e leste-sudoeste para a região litorânea vizinha. A cadeia montanhosa situada ao norte e noroeste atuou como barreira à propagação da moléstia. Considerou-se a hipótese que o agente etiológico, arbovirus Rocio, deva ter começado a infectar a população humana recentemente, tendo sido veiculado ao homem de reservatórios silvestres, aves e pequenos mamíferos, por culicídeos silvestres. Discutiu-se também prováveis formas de transmissão domiciliar. Verificou-se que os grupos populacionais que apresentaram as formas mais graves foram os de idades extremas e os que apresentavam piores condições de vida. Considerou-se que a perspectiva epidemiológica desta arbovirose é que ela persista na região, uma vez que a mesma apresenta condições ótimas para o desenvolvimento do agente etiológico, dos reservatórios e dos vetores biológicos, além de receber um contínuo afluxo de população suscetível, migrantes ou turistas