Investigation of the relationship between the structure and function of Ts2, a neurotoxin from Tityus serrulatus venom

Scorpion toxins targeting voltage-gated sodium (NaV) channels are peptides that comprise 6076 amino acid residues cross-linked by four disulfide bridges. These toxins can be divided in two groups (a and beta toxins), according to their binding properties and mode of action. The scorpion a-toxin Ts2, previously described as a beta-toxin, was purified from the venom of Tityus serrulatus, the most dangerous Brazilian scorpion. In this study, seven mammalian NaV channel isoforms (rNaV1.2, rNaV1.3, rNaV1.4, hNaV1.5, mNaV1.6, rNaV1.7 and rNaV1.8) and one insect NaV channel isoform (DmNaV1) were used to investigate the subtype specificity and selectivity of Ts2. The electrophysiology assays showed that Ts2 inhibits rapid inactivation of NaV1.2, NaV1.3, NaV1.5, NaV1.6 and NaV1.7, but does not affect NaV1.4, NaV1.8 or DmNaV1. Interestingly, Ts2 significantly shifts the voltage dependence of activation of NaV1.3 channels. The 3D structure of this toxin was modeled based on the high sequence identity (72%) shared with Ts1, another T. serrulatus toxin. The overall fold of the Ts2 model consists of three beta-strands and one a-helix, and is arranged in a triangular shape forming a cysteine-stabilized a-helix/beta-sheet (CSa beta) motif.

Clinical, haematological and biochemical responses of sheep undergoing autologous blood transfusion

Background: This study aimed to evaluate the clinical, haematological and biochemical responses to autologous blood transfusion and the feasibility of this practice in sheep. Thus, we used eight male, 8 months old sheep, weighing on average 30 kg, from which 15 mL/kg of whole blood was collected and stored in CPDA-1 bags. Blood samples were refrigerated for 8 days and subsequently re-infused. The clinical, haematological and biochemical parameters were evaluated before blood collection and reinfusion, after 10 minutes of collection and reinfusion, after 3, 6, 12, 24, 48, 96 and 192 hours after collection and reinfusion. Results: With respect to clinical parameters, we observed a decrease in heart rate after 24, 48 and 196 hours from reinfusion compared to basal values (p <0.05). Haematological variables including globular volume and erythrocyte counts showed a significant decrease (p <0.01) at all time points after collection and increased (p <0.01) at all time points after reinfusion. There was a significant increase in total protein and calcium at all time points after reinfusion (p <0.05). Conclusion: Autologous transfusion in sheep slightly altered the physiological, biochemical and haematological responses of sheep, indicating that the technique proposed is safe and can be applied in the clinical practice of this species. The 8 d period was not sufficient for complete recovery of the haematological parameters after blood collection.

Molecular confirmation of ovine herpesvirus 2-induced malignant catarrhal fever lesions in cattle from Rio Grande do Norte, Brazil

Molecular findings that confirmed the participation of ovine herpesvirus 2 (OVH-2) in the lesions that were consistent with those observed in malignant catarrhal fever of cattle are described. Three mixed-breed cattle from Rio Grande do Norte state demonstrated clinical manifestations that included mucopurulent nasal discharge, corneal opacity and motor incoordination. Routine necropsy examination demonstrated ulcerations and hemorrhage of the oral cavity, corneal opacity, and lymph node enlargement. Significant histopathological findings included widespread necrotizing vasculitis, non-suppurative meningoencephalitis, lymphocytic interstitial nephritis and hepatitis, and thrombosis. PCR assay performed on DNA extracted from kidney and mesenteric lymph node of one animal amplified a product of 423 base pairs corresponding to a target sequence within the ovine herpesvirus 2 (OVH-2) tegument protein gene. Direct sequencing of the PCR products, from extracted DNA of the kidney and mesenteric lymph node of one cow, amplified the partial nucleotide sequences (423 base pairs) of OVH-2 tegument protein gene. Blast analysis confirmed that these sequences have 98-100% identity with similar OVH-2 sequences deposited in GenBank. Phylogenetic analyses, based on the deduced amino acid sequences, demonstrated that the strain of OVH-2 circulating in ruminants from the Brazilian states of Rio Grande do Norte and Minas Gerais are similar to that identified in other geographical locations. These findings confirmed the active participation of OVH-2 in the classical manifestations of sheep associated malignant catarrhal fever.

Conductive polymer gas sensor for quantitative detection of methanol in Brazilian sugar-cane spirit

A low-cost chemiresistive gas sensor is described, made by the deposition of a thin film of a conductive polymer, poly(2-dodecanoylsulfanyl-p-phenylenevinylene), doped with dodecylbenzenesulfonic acid (10%, w/w), onto interdigitated electrodes. The sensor exhibits linear electrical conductance changes in function of the concentration of methanol present in sugar-cane spirit in the range between 0.05% and 4.0%. Since the sensor is cheap, easy to fabricate, durable, presents low power consumption, and is not sensitive to ethanol, acetic acid or water, it can be used in portable equipments for monitoring methanol levels in distilled alcoholic beverages such as Brazilian sugar-cane spirit (cachaca). (C) 2011 Elsevier Ltd. All rights reserved.

Challenges for Brazilian MNCs' international human resources management

Multinationals from emerging countries such as Brazil now take the path of internationalisation where early movers have already been. However, these companies have to develop new tools to deal with their own challenges, since they come from countries with different historical backgrounds and specificities. This paper explores challenges for Brazilian MNCs in terms of HRM when operating abroad. It presents the results of six cases of Brazilian MNCs through a grounded theory study. Results show these companies had to deal with their former economic turbulence, shortage of qualified workforce to work internationally and the need to develop HRM competencies to operate globally.

Ground-level ozone prediction using a neural network model based on meteorological variables and applied to the metropolitan area of Sao Paulo

A neural network model to predict ozone concentration in the Sao Paulo Metropolitan Area was developed, based on average values of meteorological variables in the morning (8:00-12:00 hr) and afternoon (13:00-17: 00 hr) periods. Outputs are the maximum and average ozone concentrations in the afternoon (12:00-17:00 hr). The correlation coefficient between computed and measured values was 0.82 and 0.88 for the maximum and average ozone concentration, respectively. The model presented good performance as a prediction tool for the maximum ozone concentration. For prediction periods from 1 to 5 days 0 to 23% failures (95% confidence) were obtained.

Blood gas profile of copper-poisoned in sheep treated with ammonium tetrathiomolybdate

The aim of this study was to evaluate the blood gas profile of experimentally copper-poisoned sheep (in the pre-hemolytic, hemolytic and post-hemolytic phases) that have been treated or not treated with ammonium tetrathiomolybdate. Ten lambs of the Santa Ines breed were divided into two groups: control and ATTM (treated (ammonium tetrathiomolibydate). The animals were submitted to increasing doses of copper sulfate until macroscopic hemoglobinuria was detected. All of the control animals from died within four days of hemolytic crisis, and one sheep from ATTM died during the treatment. There was no difference in blood gas parameters between experimental groups. Higher values of pCO(2) were observed during the hemolytic crisis (HC) in both groups. The control group had higher mean values of hCO(3) in the times HC and 2 days after hemolytic crisis (dA) when compared with the time 15 before hemolytic crises (dB). The sheep that were treated with ATTM presented lower values of hCO(3) at 7dB and higher levels at the HC. The control and ATTM groups exhibited higher values of BE during the HC. Poisoning resulted in disorder in the acid-base equilibrium, characterized by metabolic alkalosis and respiratory acidosis. Treatment with ATTM was able to reverse the changes in acid-base balance in copper poisoning sheep.

Tuning the reaction products of ruthenium and ciprofloxacin for studies of DNA interactions

This work presents two potential metallo-drugs, the ionic (C17H19FN3O3)(3)[RuCl6]center dot 3H(2)O (1) and the coordination [Ru(C17H17FN3O3)(3)]center dot 4H(2)O (2) compounds, obtained by the combination of ruthenium(III) and ciprofloxacin in different synthetic conditions. The ESI MS spectrum of 1 displayed a main peak at m/z = 994.6, assigned to the gaseous phase adduct (ciprofloxacin)(3)center dot H+, while 2 featured peaks at m/z 1093.3 and 547.1 ascribed to [Ru(C17H17FN3O3)(3)center dot H+-4H(2)O](+) and [Ru(C17H17FN3O3)(3)center dot 2H(+)-4H(2)O](2+). Thermal analysis corroborated the proposed water content for both complexes. Absorption spectra of the compounds in aqueous medium are dominated by ciprofloxacin transitions in the UV region but displayed weak bands in the visible region, assigned to ligand field transitions. The cyclic voltammograms of 2 exhibited a quasi-reversible process ascribed to the Ru(II)/(III) redox pair at -0.25V (vs. SHE) while 1 displayed this process at -0.11 V, showing that the central ruthenium ion is stabilized in the (III) oxidation state by the coordination to the hard oxygen atoms of ciprofloxacin. The solubility of 1 is pH dependent (as well as free ciprofloxacin) while 2 is fully water soluble and stable under physiological pH for at least 48 h. The compounds are also stable under incubation conditions (stomach pH and 37 degrees C) without significant pH lowering. An interaction study of 2 with ct-DNA showed a value of K-b = 2.47 (+/- 0.89) x 10(4) mol(-1) L for the intrinsic binding constant.

A estrutura de provisão dos serviços de saneamento básico no Brasil: uma análise comparativa do desempenho dos provedores públicos e privados

O presente artigo realiza uma análise que compara o desempenho dos provedores públicos e privados de serviços de saneamento básico no Brasil. As diferenças de desempenho entre os provedores que, de acordo com a literatura, estão submetidos a diferentes incentivos foram avaliadas com base nos dados do Sistema Nacional de Informações sobre Saneamento (Snis) de 2010 a partir de uma estimativa em cross-section para uma amostra de 4.930 municípios brasileiros. Os resultados não fornecem evidências fortes de que um grupo seja superior a outro na maior parte dos indicadores. Dado que os grupos revelaram superioridade em indicadores específicos, a contribuição deste estudo é propor o desenho de uma política que considere diversas modalidades de gestão e provisão como possível solução para o desafio de universalizar os serviços no país.

Tecendo a colcha de retalhos: a bricolagem como alternativa para a pesquisa educacional

A intensidade das mudanças sociais em curso colocou em xeque o legado da modernidade. As verdades elaboradas pela ciência moderna têm sofrido fortes abalos. Até mesmo o modo de produzir conhecimentos é questionado nos tempos atuais. Dentre as alternativas emergentes, encontra-se a bricolagem. Os bricoleurs apelam para uma variedade de métodos, instrumentos e referenciais teóricos que lhes possibilitem acessar e tecer as interpretações de diferentes origens. Impulsionados pelos Estudos Culturais, denunciam as relações de poder que influenciam os discursos científicos postos em circulação. O presente artigo discute os pressupostos e procedimentos metodológicos e oferece um exemplo de uma pesquisa educacional inspirada na bricolagem.

Acid-base status of ammonia-poisoned steers

Although several studies on ammonia poisoning have been carried out, there is a lack of information on acid-base balance status in ammonia-poisoned cattle. Twelve crossbred steers received intraruminally 0.5 g of urea per kg of body weight in order to induce a clinical picture of ammonia poisoning. Blood samples were collected throughout the trials in order to determine the blood ammonia, lactate, and perform blood gas analysis. All cattle presented a classical clinical picture of ammonia poisoning, with a blood ammonia concentration rising progressively from the beginning until reaching higher values at 180 min (27 ± 3 to 1719 ± 101 μmol L-1), with a similar pattern occurring with blood L-lactate levels (1.7 ± 0.3 to 26.0 ± 1.7 mmol L-1). The higher the blood ammonia concentration the higher the blood L-lactate levels (r = 0.86). All animals developed metabolic acidosis, as blood pH lowered to 7.24 0.03. The steers tried to compensate the metabolic acidosis mainly through the use of blood buffers and respiratory adjustments by lowering the pCO2 levels in the blood to 32.8 ± 2.0 mm Hg.