Hepatocyte lesions and cellular immune response in yellow fever infection

The study of the in-situ cellular immune response is very important for the understanding of different liver infections. In the present study, 53 liver samples obtained by viscerotomy from patients who died during the course of jungle yellow fever were analyzed. The diagnosis was confirmed by serology, viral isolation and virus-specific immunohistochemistry. The specimens were analyzed by immunohistochemistry using specific antibodies for apoptosis, CD45RO, CD4, CD8, CD20, S100, CD57 and CD68. Quantitative analysis of the labeling pattern showed a clear predominance of the different phenotypes in the portal tract and midzone region of the acini. There was a predominance of T CD4+ lymphocytes, accompanied by the presence of T CD8+ lymphocytes, natural killer cells (CD57), macrophages and antigen-presenting cells (S100). The disproportion between the intensity of inflammation and the degree of hepatic injury was probably due to the intense apoptotic component, which classically does not induce an inflammatory response. The present study demonstrates that, despite the disproportion between injury and inflammation, the cellular immune response plays an important role in the pathogenesis of the hepatocytic injury observed in yellow fever, probably as a result of cytolytic actions through mechanisms involving MHC II and the activation of Fas receptors and granzymes/perforins. (C) 2006 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

Prevalence of enzootic bovine leukosis among buffaloes (Bubalus bubalis) in the Ribeira valley region state of São Paulo, Brazil

The prevalence of enzootic bovine leukosis (EEL) among female buffaloes reared in 15 herds of the Ribeira Valley, Brazil, was zero. Serum samples(470)were submitted to agar gel immunodiffusion (AGID) with a glycoprotein antigen(gp51) for the diagnosis of EBL. The fact that no seroreactive animals were detected may probably be due to the predominantly extensive management of buffaloes and their little or no contact with cattle, the major source of EEL infection.

5-HT2A serotoninergic receptor in the locus coeruleus participates in the first phase of lipopolysaccharide-induced fever

This study was aimed at testing the hypothesis that serotoninergic receptors in the locus coeruleus (LC) play a role in bacterial lipopolysaccharide-induced fever. To this end, 5-HT1A (WAY-100635; 3 mu g/100 nL) and 5-HT2A (ketanserin; 2 mu g/100 nL) antagonists were microinjected into the LC and body temperature was monitored by biotelemetry. Intra-LC microinjections of ketanserin or WAY-100635 caused no change in body temperature of euthermic animals. 5-HT2A antagonism abolished the first phase of the lipopolysaccharide-induced fever. Taken together, these results indicate that serotonin acting on 5-HT2A receptors in the LC mediates the first phase of the febrile response, whereas 5-HT1A receptors are not involved in the lipopolysaccharide-induced fever.

STUDY OF AMNONIFYING BACTERIA BEHAVIOR IN THE LAKES CARIOCA AND D-HELVECIO (RIO-DOCE-VALLEY-MG)

The study of the amnonifying bacteria behavior in the lakes Carioca and D. Helvecio, which belong to the natural lacustrine system of the Rio Doce Valley - Minas Gerais - Brazil, during the period from March to November, showed a similar seasonal variation in both lakes, with higher population density in March and November (raining period) and lower density in May, July and September (dry period). The vertical variation was also relatively similar for both lakes, were during the thermal stratification the distribution was regular along the water column, while during the period of thermal stratification the populational density was remarkably different at different depths. The characterized ammonifying types to the genera Acinetobacter, Moraxella and Proteus, which in culture reveal high amnonifying activity with values which have reached 30,8 mug/l of ammonia per population unity (105 bacteria/ml).

Rift to post-rift evolution of a passive continental margin: the Ponta Grossa Arch, SE Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Malignant catarrhal fever-like lesions associated with ovine herpesvirus-2 infection in young calves (Bos indicus): a case report

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ticks (Acari: Ixodidae) within various phytophysiognomies of a Cerrado reserve in UberlA cent ndia, Minas Gerais, Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thermal structure, heat content and stability of two lakes in The National Park of Rio Doce Valley (Minas Gerais, Brazil)

The thermal structure, heat content and stability were studied in Lakes Dom Helvécio and Carioca during an annual cycle. It was found that the maximum heat content, stability and work of the wind in Lake Dom Helvécio correspond to two, four and four times, respectively, the values for the Lake Carioca. These difference can be attributed to morphometric differences in the lakes. A long-term record of heat content and stability for lake Carioca is also presented. Diel variations were studied in summer and winter. The tropicality of the lakes is discussed and compared with other lacustrine systems. © 1989 Kluwer Academic Publishers.

Fever response induced by intravenous and intracerebrovascular injection of pyrogen in thyroidectomised and protein-calorie malnourished rabbits

The development of a fever in response to intravenous (IV, 1.5 μg/kg body mass) and intracerebroventricular (ICV, 1.5 μg/animal) injections of Escherichia coli lipopolysaccharide (LPS) was studied in control, thyroidectomised and protein-calorie malnourished rabbits (New Zealand Whites, n = 55). ICV injection of LPS is control rabbits produced a fever response, the characteristics of which differed from those obtained after IV pyrogen injection. Thyroid deficiency caused an attenuated fever response, irrespective of whether LPS had been administered by IV or ICV injection. Protein-calorie malnourished rabbits showed a smaller fever response after IV or ICV pyrogen injections. Malnourished rabbits, refed over a period of 15 days, showed a typical biphasic fever response, but with lower magnitude than controls. The results of these experiments suggest that ICV injection of LPS is not an appropriate model for the study of fever mechanisms in disease states, and that the attenuated fever response observed in protein-calorie malnourished rabbits may be related, at least in part, to a decreased ability to produce the endogenous pyrogen interleukin-1.

The eukaryotic translation initiation factor 3 subunit L protein interacts with Flavivirus NS5 and may modulate yellow fever virus replication

Background: Yellow fever virus (YFV) belongs to the Flavivirus genus and causes an important disease. An alarming resurgence of viral circulation and the expansion of YFV-endemic zones have been detected in Africa and South America in recent years. NS5 is a viral protein that contains methyltransferase and RNA-dependent RNA polymerase (RdRp) domains, which are essential for viral replication, and the interactions between NS5 and cellular proteins have been studied to better understand viral replication. The aim of this study was to characterize the interaction of the NS5 protein with eukaryotic translation initiation factor 3 subunit L (eIF3L) and to evaluate the role of eIF3L in yellow fever replication. Methods. To identify interactions of YFV NS5 with cellular proteins, we performed a two-hybrid screen using the YFV NS5 RdRp domain as bait with a human cDNA library, and RNApol deletion mutants were generated and analyzed using the two-hybrid system for mapping the interactions. The RNApol region involved was segmented into three fragments and analyzed using an eIF3L-expressing yeast strain. To map the NS5 residues that are critical for the interactions, we performed site-direct mutagenesis in segment 3 of the interaction domain (ID) and confirmed the interaction using in vitro assays and in vivo coimmunoprecipitation. The significance of eIF3L for YFV replication was investigated using eIF3L overexpression and RNA interference. Results: In this work, we describe and characterize the interaction of NS5 with the translation factor eIF3L. The interaction between NS5 and eIF3L was confirmed using in vitro binding and in vivo coimmunoprecipitation assays. This interaction occurs at a region (the interaction domain of the RNApol domain) that is conserved in several flaviviruses and that is, therefore, likely to be relevant to the genus. eIF3L overexpression and plaque reduction assays showed a slight effect on YFV replication, indicating that the interaction of eIF3L with YFV NS5 may play a role in YFV replication. Conclusions: Although the precise function of eIF3L on interactions with viral proteins is not entirely understood, these results indicate an interaction of eIF3L with YF NS5 and that eIF3L overexpression facilitates translation, which has potential implications for virus replication. © 2013 Morais et al.; licensee BioMed Central Ltd.

Litoestratigrafia da bacia do Araripe: reavaliação e propostas para revisão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Contribuição ao conhecimento de processos atuantes no rifteamento continental, por traços de fissão em zircões e apatitas, aplicados no rift continental do sudeste do Brasil, bacias de Taubaté, Resende, Volta Redonda e circunvizinhanças

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)