Magnetically channeled accretion in T Tauri stars : a dynamical process

We review observational evidence and open issues related to the process of magnetospheric accretion in T Tauri stars. Emphasis is put on recent numerical simulations and observational results which suggest that the interaction between the stellar magnetosphere and the inner accretion disk is a highly time dependent process on timescales ranging from hours to months.Comment: To appear in Open Issues in Local Star Formation and Early Stellar Evolution, eds. J. Lepine, J. Gregorio-Hete

The role of chemokines and chemokine receptors in eosinophil activation during inflammatory allergic reactions

Chemokines are important chemotactic cytokines that play a fundamental role in the trafficking of leukocytes to sites of inflammation. They are also potent cell-activating factors, inducing cytokine and histamine release and free radical production, a fact that makes them particularly important in the pathogenesis of allergic inflammation. The action of chemokines is regulated at the level of agonist production and processing as well as at the level of receptor expression and coupling. Therefore, an analysis of the ligands must necessarily consider receptors. Eosinophils are target cells involved in the allergic inflammatory response since they are able to release a wide variety of mediators including CC and CXC chemokines and express their receptors. These mediators could damage the airway epithelial cells and might be important to stimulate other cells inducing an amplification of the allergic response. This review focuses on recently emerging data pertaining to the importance of chemokines and chemokine receptors in promoting eosinophil activation and migration during the allergic inflammatory process. The analysis of the function of eosinophils and their chemokine receptors during allergic inflammation might be a good approach to understanding the determinants of asthma severity and to developing novel therapies

Voltammetric behavior of benznidazole at a DNA-electrochemical biosensor

Benznidazole is a drug used commonly as a therapeutic agent against Chagas' disease in Brazil. To clarify the cytotoxic action of benznidazole the electrochemical reduction of benznidazole has been investigated using a DNA-electrochemical biosensor, prepared by modification of a glassy carbon electrode with DNA, and the results compared with reduction at a bare glassy carbon electrode. The dependence of peak potential with pH follows slopes of 59 and 52 mV per pH unit in acid media, respectively, which corresponds to a mechanism involving the same number of electrons and protons. In neutral and alkaline solution no significant dependence of peak potential with pH was found. During the electrochemical reduction of benznidazole the formation of the hydroxylamine derivative occurs, involving a total of four electrons. The potentials for reduction were less negative when using the DNA-modified glassy carbon electrode than at the bare glassy carbon electrode although the mechanism was the same, and at pH 7.51 the peak current was four times higher than that obtained with the bare electrode. The DNA-biosensor enabled pre-concentration of the drug onto the electrode surface and the in situ damage caused to the DNA on the electrode surface by the product of benznidazole reduction could be detected electrochemically. The results are in agreement with the hypothesis that the hydroxylamine derivative is the reactive species responsible for the cytotoxic action of benznidazole.http://www.sciencedirect.com/science/article/B6TGX-45JYJC6-4/1/f4a420f6f46e2c3d977fbcc436da8f2

Production of extracellular l-asparaginase: from bioprospecting to the engineering of an antileukemic biopharmaceutical

L-asparaginase is an enzyme clinically accepted as an anti-tumor agent for the treatment of acute lymphoblastic leukemia and lymphosarcoma. The main focus of this study is to provide a thorough overview on microbial production of such a biopharmaceutical

Treatment of Bothrops alternatus envenomation by Curcuma longa and Calendula officinalis extracts and ar-turmerone Tratamento local do envenenamento por Bothrops alternatus com extrato de Curcuma longa e Calendula officinalis e ar-turmerone

It was investigated the efficiency of two extracts of plants and one fraction of their properties against the local effects of bothropic envenomation. Bothrops alternatus venom (1.25µg) diluted in 100µl of sterile saline solution was inoculated (intradermally) into the shaved dorsal back skin of 30 New Zealand rabbits. The animals were divided in six groups receiving the following treatments: group I: subcutaneous application of Curcuma longa extract (1.0ml); group II: topic treatment of Curcuma longa hydroalcoholic extract (1.0ml); group III: topic application of ar-turmerone in vaseline (1.0g); group IV: topic application of Curcuma longa methanolic extract (1.0ml); group V: topic application of Calendula officinalis ointment (1.0g); group VI: topic application of saline (1.0ml). These treatments were done at 30 minutes, and at 2, 4, 24 and 72 hours after venom inoculation. Intensity of local edema, hemorrhagic halo and necrosis were evaluated until 168h after that. Additionally, seven days after the Bothrops venom inoculation, blood was collected from heart with and without EDTA (10%) for hemogram and biochemical parameters (total protein, blood urea nitrogen, creatinine, and fibrinogen) and all the animals were anesthetized, sacrificed by ether inhalation and submitted to necropsy. Fragments of tissues were taken for histopathological evaluation. The most efficient treatment for inhibition of edema, necrosis and local hemorrhage after Bothrops alternatus venom was the topic application of ar-turmerone.<br>Investigou-se a eficácia do extrato de plantas no tratamento local do envenenamento botrópico. Veneno de serpentes Bothrops alternatus (1,25µg) diluído em 100µl de solução salina estéril foi inoculado (via intradérmica) entre as escápulas de 30 coelhos. Os animais foram divididos em seis grupos (tratamentos): grupo I: tratamento subcutâneo com extrato de Curcuma longa; grupo II: tratamento tópico com extrato hidroalcoólico de Curcuma longa; grupo III: tratamento tópico com ar-turmerone em vaselina; grupo IV: tratamento tópico com extrato metanólico de Curcuma longa; grupo V: tratamento tópico com pomada de Calendula officinalis e grupo VI: aplicação tópica de solução salina a 0,9% (Controle). Os tratamentos foram realizados 30 minutos, 2h, 4h, 24h e 72h após a inoculação do veneno. Foram avaliados intensidade de edema local (com paquímetro), halo hemorrágico (régua com gabaritos circulares) e presença de necrose. Sete dias após a inoculação do veneno botrópico (168h) foi coletado sangue do coração, com e sem EDTA, para realização de hemograma, dosagem plasmática de fibrinogênio e dosagens séricas de proteína total, uréia e creatinina. Após as coletas de sangue, todos os animais foram anestesiados, sacrificados com inalação pelo éter etílico e necropsiados. Fragmentos de pele foram retirados para avaliação histopatológica. Os resultados obtidos mostraram que o tratamento mais eficaz para inibição da evolução do edema, necrose e hemorragia local após envenenamento com Bothrops alternatus foi a aplicação tópica de ar-turmerone