Early and late neuropathological features of meningoencephalitis associated with Maraba virus infection

Maraba virus is a member of the genus Vesiculovirus of the Rhabdoviridae family that was isolated in 1983 from sandflies captured in the municipality of Maraba, state of Pará, Amazônia, Brazil. Despite 30 years having passed since its isolation, little is known about the neuropathology induced by the Maraba virus. Accordingly, in this study the histopathological features, inflammatory glial changes, cytokine concentrations, and nitric oxide activity in the encephalon of adult mice subjected to Maraba virus nostril infection were evaluated. The results showed that 6 days after intranasal inoculation, severe neuropathological-associated disease signs appeared, including edema, necrosis and pyknosis of neurons, generalized congestion of encephalic vessels, and intra- and perivascular meningeal lymphocytic infiltrates in several brain regions. Immunolabeling of viral antigens was observed in almost all central nervous system (CNS) areas and this was associated with intense microglial activation and astrogliosis. Compared to control animals, infected mice showed significant increases in interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon (INF)-γ, MCP-1, nitric oxide, and encephalic cytokine levels. We suggest that an exacerbated inflammatory response in several regions of the CNS of adult BALB/c mice might be responsible for their deaths.

Microglia and neurons in the hippocampus of migratory sandpipers

The semipalmated sandpiper Calidris pusilla and the spotted sandpiper Actitis macularia are long- and short-distance migrants, respectively. C. pusilla breeds in the sub-arctic and mid-arctic tundra of Canada and Alaska and winters on the north and east coasts of South America. A. macularia breeds in a broad distribution across most of North America from the treeline to the southern United States. It winters in the southern United States, and Central and South America. The autumn migration route of C. pusilla includes a non-stop flight over the Atlantic Ocean, whereas autumn route of A. macularia is largely over land. Because of this difference in their migratory paths and the visuo-spatial recognition tasks involved, we hypothesized that hippocampal volume and neuronal and glial numbers would differ between these two species. A. macularia did not differ from C. pusilla in the total number of hippocampal neurons, but the species had a larger hippocampal formation and more hippocampal microglia. It remains to be investigated whether these differences indicate interspecies differences or neural specializations associated with different strategies of orientation and navigation.

Reconstructive dosimetry for cutaneous radiation syndrome

According to the International Atomic Energy Agency (IAEA), a relatively significant number of radiological accidents have occurred in recent years mainly because of the practices referred to as potentially high-risk activities, such as radiotherapy, large irradiators and industrial radiography, especially in gammagraphy assays. In some instances, severe injuries have occurred in exposed persons due to high radiation doses. In industrial radiography, 80 cases involving a total of 120 radiation workers, 110 members of the public including 12 deaths have been recorded up to 2014. Radiological accidents in industrial practices in Brazil have mainly resulted in development of cutaneous radiation syndrome (CRS) in hands and fingers. Brazilian data include 5 serious cases related to industrial gammagraphy, affecting 7 radiation workers and 19 members of the public; however, none of them were fatal. Some methods of reconstructive dosimetry have been used to estimate the radiation dose to assist in prescribing medical treatment. The type and development of cutaneous manifestations in the exposed areas of a person is the first achievable gross dose estimation. This review article presents the state-of-the-art reconstructive dosimetry methods enabling estimation of local radiation doses and provides guidelines for medical handling of the exposed individuals. The review also presents the Chilean and Brazilian radiological accident cases to highlight the importance of reconstructive dosimetry.

Avaliação da toxicidade aguda do extrato das cascas de Pithecellobium cochliocarpum (Gomez) Macbr / Evaluation of acute toxicity of the Pithecellobium cochliocarpum (Gomez) Macbr bark extract

O uso popular, e mesmo o tradicional, não são suficientes para validar as plantas medicinais como medicamentos eficazes e seguros. Para melhor entendimento, é necessário avaliar a relação risco/benefício de seu uso, por meio de estudos toxicológicos. O objetivo desta pesquisa foi estimar a toxicidade aguda do extrato etanólico das cascas secas de Pithecellobium cochliocarpum (Gomez) Macbr através da obtenção da dose letal (DL50) em roedores, e da Concentração letal (CL50) frente à Artemia salina Leach. Foram realizados experimentos por via oral e intraperitoneal utilizando camundongos fêmeas albinos Swiss (Mus musculus) (n=6). Por via oral foram administradas 3 doses (1.000, 3.000 e 5.000 mg Kg-1) e por via entraperitoneal, 5 doses (155, 160, 176, 345,6 e 414,72 Kg-1). Os sinais comportamentais foram avaliados durante uma hora após a administração do extrato, ficando em observação até 48 horas. O número de óbitos foi quantificado para posterior cálculo da DL50. A administração por via intraperitoneal foi realizada em intervalo de 5 minutos para cada animal. Nos ensaios de toxicidade por via oral a solução foi introduzida por via intragástrica através de cânula metálica acoplada a seringa (gavagem) no mesmo intervalo de tempo utilizado pela via intraperitoneal. Os animais do grupo de administração oral apresentaram algumas reações, porém não letais até a dose de 5.000 mg Kg-1. A DL50 para a via intraperitoneal foi 257, 49 mg Kg-1 (muito tóxico, grau 4) (Schuartsman, 1980). A CL50 (543,5 µg Kg-1) demonstrou ser tóxica frente à A. salina. Conclui-se que sob condições agudas de exposição, o extrato do Pithecellobium cochliocarpum é um agente tóxico, devendo ser considerado como tal, dependendo da dose administrada ou absorvida, do etempo e frequência de exposição e das vias de administração.

The popular use, and even the traditional one, is not enough to validate medicinal plants as effective and safe medicines. For a better understanding, it is necessary to assess the risk / benefit ratio of their use through toxicological studies. The aim of this work was to evaluate the acute toxicity of Pithecellobium cochliocarpum (Gomez) Macbr dried bark ethanolic extract through its lethal dose (LD50), in mice, and lethal concentration (LC50) in relation to Artemia salina Leach. Experiments were performed by oral and intraperitoneal route using female Swiss albino mice (Mus musculus) (n = 6). The first three doses were given orally (1,000, 3,000 and 5,000 mg kg-1) and the last five doses were given intraperitoneally (155, 160, 176, 345.6 and 414.72 Kg-1). The behavioral signs were evaluated one hour after administration of the extract, being observed up to 48 hours. The number of deaths was quantified for subsequent calculation of LD50. The intraperitoneal administration was carried out at an interval of 5 minutes for each animal. For the oral toxicity test, the solution was introduced in the digestive system of the animals through a metal cannula coupled to a syringe (gavage) at the same time interval used for the intraperitoneal route. The animals from the oral group presented some reactions, but they were not lethal up to the dose of 5.000 mg kg-1. The LD50 for the intraperitoneal group was 257.49 mg kg-1 (very toxic, grade 4) (Schuartsman, 1980). The LC50 (543.5 mg kg-1) was toxic to A. salina. We can conclude that, under acute conditions of exposure, the Pithecellobium cochliocarpum extract is a poisonous agent and should be considered as such depending on the administered or absorbed dose, the time and frequency of exposure, and the administration routes.

Functional changes of dendritic cells in hypersensivity reactions to amoxicillin

A better understanding of dendritic cell (DC) involvement in responses to haptenic drugs is needed, because it represents a possible approach to the development of an in vitro test, which could identify patients prone to drug allergies. There are two main DC subsets: plasmacytoid DC (pDC) and myeloid DC (mDC). β-lactams form hapten-carrier conjugates and may provide a suitable model to study DC behavior in drug allergy reactions. It has been demonstrated that drugs interact differently with DC in drug allergic and non-allergic patients, but there are no studies regarding these subsets. Our aim was to assess the functional changes of mDC and pDC harvested from an amoxicillin-hypersensitive 32-year-old woman who experienced a severe maculopapular exanthema as reflected in interleukin-6 (IL-6) production after stimulation with this drug and penicillin. We also aim to demonstrate, for the first time, the feasibility of this method for dendritic cell isolation followed by in vitro stimulation for studies of drug allergy physiopathology. DC were harvested using a double Percoll density gradient, which generates a basophil-depleted cell (BDC) suspension. Further, pDC were isolated by blood DC antigen 4-positive magnetic selection and gravity filtration through magnetized columns. After stimulation with amoxicillin, penicillin and positive and negative controls, IL-6 production was measured by ELISA. A positive dose-response curve for IL-6 after stimulation with amoxicillin and penicillin was observed for pDC, but not for mDC or BDC suspension. These preliminary results demonstrate the feasibility of this methodology to expand the knowledge of the effect of dendritic cell activation by drug allergens.

Atividade anti-helmíntica dos extratos aquoso e etanólico do fruto da Morinda citrifolia sobre Ascaridia galli / Anthelmintic activity of aqueous and ethanolic extracts of Morinda citrifolia fruit on Ascaridia galli

A atividade anti-helmíntica dos extratos aquoso e etanólico do fruto da Morinda citrifolia (noni) foi avaliada em aves poedeiras naturalmente infectadas por Ascaridia galli. A atividade anti-helmíntica in vitro foi determinada em parasitos adultos. O extrato aquoso e etanólico foram testados nas seguintes concentrações: 1,69; 3,37; 6,74; 13,48 e 26,96 mg.mL-1 e 4,17; 8,34; 16,68; 33,36 e 66,72 mg.mL-1, respectivamente. A atividade anti-helmíntica in vivo foi determinada administrando-se, durante três dias consecutivos, o extrato aquoso (50,1 mg.mL-1) e etanólico (24,6 mg.mL-1), sendo 10 mL.kg-1. Posteriormente, as aves foram sacrificadas e necropsiadas para contagem dos helmintos remanescentes. Os dados obtidos foram analisados estatisticamente, utilizando-se o teste de Student-Newman-Keuls. Nas concentrações 13,48 e 26,96 mg.mL-1, o extrato aquoso apresentou taxa de mortalidade de 46,67 e 50 por cento, respectivamente, sendo estatisticamente diferente do controle negativo (P < 0,05). O extrato etanólico apresentou diferença significativa do controle negativo (diluente) (P < 0,05) para as concentrações 33,36 e 66,72 mg.mL-1, expressando taxa de mortalidade de 66,67 e 76,67 por cento, respectivamente. No teste in vivo, o extrato aquoso do fruto do noni apresentou percentual de eliminação de 27,08 por cento, diferindo estatisticamente do grupo controle. Não houve diferença significativa entre os tratamentos com extrato etanólico e controle (P > 0,05). Conclui-se que a atividade anti-helmíntica do fruto do noni, no teste in vitro, apresentou resultados satisfatórios, havendo necessidade de estudos com maiores concentrações no teste in vivo.

The anthelmintic activity of aqueous and ethanolic extracts of Morinda citrifolia fruit (noni) was evaluated in chicken naturally infected by Ascaridia galli. The anthelmintic activity in vitro was determined in adult parasites. The aqueous and ethanolic extracts were used in the following concentrations: 1.69; 3.37; 6.74; 13.48 e 26.96 mg.mL-1 and 4.17; 8.34; 16.68; 33.36 and 66.72 mg.mL-1, respectively. The anthelmintic activity in vivo was determined by the administration of 10 mL.kg-1 of the aqueous (50.1 mg.mL-1) and ethanolic (24.6 mg.mL-1) extracts during three consecutive days. Later the chickens were euthanized and necropsy was performed in order to count the remaining helminths. The data were analyzed by the Student-Newman-Keuls test. In the concentrations of 13.48 and 26.96 mg.mL-1, the aqueous extract demonstrated mortality of 46.67 and 50 percent, respectively, there was a significative difference from the negative control (P < 0.05). The ethanolic extract presented statistical difference from the negative control (diluent) (P < 0.05) for the concentrations of 33.36 and 66.72 mg.mL-1, expressed by a mortality rate of 66.67 and 76.67 percent, respectively. In the in vivo test, the aqueous extract of noni fruit showed 27.08 percent of elimination, deferring statistically from the control group. There was no statistical difference between the ethanolic extract treatments and the control (P > 0.05). It follows that the anthelmintic activity of noni fruit test showed satisfactory results in vitro, there is a need for studies in higher concentrations in the in vivo test.

Molecular epidemiology of type 1 and 2 dengue viruses in Brazil from 1988 to 2001

Dengue is a mosquito-borne viral infection that in recent decades has become a major international public health concern. Epidemic dengue fever reemerged in Brazil in 1981. Since 1990 more than one dengue virus serotype has been circulating in this tropical country and increasing rates of dengue hemorrhagic fever and dengue shock syndrome have been detected every year. Some evidence supports the association between the introduction of a new serotype and/or genotype in a region and the appearance of dengue hemorrhagic fever. In order to study the evolutionary relationships and possible detection of the introduction of new dengue virus genotypes in Brazil in the last years, we analyzed partial nucleotide sequences of 52 Brazilian samples of both dengue type 1 and dengue type 2 isolated from 1988 to 2001 from highly endemic regions. A 240-nucleotide-long sequence from the envelope/nonstructural protein 1 gene junction was used for phylogenetic analysis. After comparing the nucleotide sequences originally obtained in this study to those previously studied by others, and analyzing the phylogenetic trees, we conclude that, after the initial introduction of the currently circulating dengue-1 and dengue-2 genotypes in Brazil, there has been no evidence of introduction of new genotypes since 1988. The increasing number of dengue hemorrhagic fever cases seen in Brazil in the last years is probably associated with secondary infections or with the introduction of new serotypes but not with the introduction of new genotypes.