Morphological changes in distant muscle fibers following thermal injury in Wistar rats

PURPOSE: Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. METHODS: Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45% of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. RESULTS: Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. CONCLUSION: This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45% of the body surface.

Central chemoreceptors and neural mechanisms of cardiorespiratory control

The arterial partial pressure (P CO2) of carbon dioxide is virtually constant because of the close match between the metabolic production of this gas and its excretion via breathing. Blood gas homeostasis does not rely solely on changes in lung ventilation, but also to a considerable extent on circulatory adjustments that regulate the transport of CO2 from its sites of production to the lungs. The neural mechanisms that coordinate circulatory and ventilatory changes to achieve blood gas homeostasis are the subject of this review. Emphasis will be placed on the control of sympathetic outflow by central chemoreceptors. High levels of CO2 exert an excitatory effect on sympathetic outflow that is mediated by specialized chemoreceptors such as the neurons located in the retrotrapezoid region. In addition, high CO2 causes an aversive awareness in conscious animals, activating wake-promoting pathways such as the noradrenergic neurons. These neuronal groups, which may also be directly activated by brain acidification, have projections that contribute to the CO2-induced rise in breathing and sympathetic outflow. However, since the level of activity of the retrotrapezoid nucleus is regulated by converging inputs from wake-promoting systems, behavior-specific inputs from higher centers and by chemical drive, the main focus of the present manuscript is to review the contribution of central chemoreceptors to the control of autonomic and respiratory mechanisms.

Cognitive control associated with irritability induction: an autobiographical recall fMRI study

OBJECTIVE: Despite the relevance of irritability emotions to the treatment, prognosis and classification of psychiatric disorders, the neurobiological basis of this emotional state has been rarely investigated to date. We assessed the brain circuitry underlying personal script-driven irritability in healthy subjects (n = 11) using functional magnetic resonance imaging. METHOD: Blood oxygen level-dependent signal changes were recorded during auditory presentation of personal scripts of irritability in contrast to scripts of happiness or neutral emotional content. Self-rated emotional measurements and skin conductance recordings were also obtained. Images were acquired using a 1,5T magnetic resonance scanner. Brain activation maps were constructed from individual images, and between-condition differences in the mean power of experimental response were identified by using cluster-wise nonparametric tests. RESULTS: Compared to neutral scripts, increased blood oxygen level-dependent signal during irritability scripts was detected in the left subgenual anterior cingulate cortex, and in the left medial, anterolateral and posterolateral dorsal prefrontal cortex (cluster-wise p-value < 0.05). While the involvement of the subgenual cingulate and dorsal anterolateral prefrontal cortices was unique to the irritability state, increased blood oxygen level-dependent signal in dorsomedial and dorsal posterolateral prefrontal regions were also present during happiness induction. CONCLUSION: Irritability induction is associated with functional changes in a limited set of brain regions previously implicated in the mediation of emotional states. Changes in prefrontal and cingulate areas may be related to effortful cognitive control aspects that gain salience during the emergence of irritability.

Simvastatin-induced cardiac autonomic control improvement in fructose-fed female rats

OBJECTIVE: Because autonomic dysfunction has been found to lead to cardiometabolic disorders and because studies have reported that simvastatin treatment has neuroprotective effects, the objective of the present study was to investigate the effects of simvastatin treatment on cardiovascular and autonomic changes in fructose-fed female rats. METHODS: Female Wistar rats were divided into three groups: controls (n=8), fructose (n=8), and fructose+ simvastatin (n=8). Fructose overload was induced by supplementing the drinking water with fructose (100 mg/L, 18 wks). Simvastatin treatment (5 mg/kg/day for 2 wks) was performed by gavage. The arterial pressure was recorded using a data acquisition system. Autonomic control was evaluated by pharmacological blockade. RESULTS: Fructose overload induced an increase in the fasting blood glucose and triglyceride levels and insulin resistance. The constant rate of glucose disappearance during the insulin intolerance test was reduced in the fructose group (3.4+ 0.32%/min) relative to that in the control group (4.4+ 0.29%/min). Fructose+simvastatin rats exhibited increased insulin sensitivity (5.4+0.66%/min). The fructose and fructose+simvastatin groups demonstrated an increase in the mean arterial pressure compared with controls rats (fructose: 124+2 mmHg and fructose+simvastatin: 126 + 3 mmHg vs. controls: 112 + 2 mmHg). The sympathetic effect was enhanced in the fructose group (73 + 7 bpm) compared with that in the control (48 + 7 bpm) and fructose+simvastatin groups (31+8 bpm). The vagal effect was increased in fructose+simvastatin animals (84 + 7 bpm) compared with that in control (49 + 9 bpm) and fructose animals (46+5 bpm). CONCLUSION: Simvastatin treatment improved insulin sensitivity and cardiac autonomic control in an experimental model of metabolic syndrome in female rats. These effects were independent of the improvements in the classical plasma lipid profile and of reductions in arterial pressure. These results support the hypothesis that statins reduce the cardiometabolic risk in females with metabolic syndrome.

Importância da gordura alimentar na prevenção e no controle de distúrbios metabólicos e da doença cardiovascular

A Organização Mundial da Saúde (OMS) reiterou recentemente que o consumo de dietas inadequadas e a inatividade física estão entre os dez principais fatores de mortalidade. Diversos ensaios aleatorizados demonstram que intervenções alimentares adequadas podem diminuir ou prevenir significativamente o aparecimento de várias doenças crônicas não transmissíveis. Neste contexto, o papel da dieta vem sendo exaustivamente avaliado em estudos clínicos e epidemiológicos. Assim, já foi bem estabelecido na literatura que a quantidade e o tipo de gordura alimentar exercem influência direta sobre fatores de risco cardiovascular, tais como a concentração de lípides e de lipoproteínas plasmáticas, bem como sua associação a processos inflamatórios. Os ácidos graxos participam de complexos sistemas de sinalização intracelular, função que vem sendo bastante explorada. Os ácidos graxos poli-insaturados não somente influenciam a composição das membranas, metabolismo celular e sinais de tradução, mas também modulam a expressão de genes, regulando a atividade e a produção de diversos fatores de transcrição. A proposta deste artigo é rever tópicos relevantes referentes ao metabolismo de lípides e os relacionar a terapias nutricionais que possam contribuir para a prevenção e o tratamento de doenças associadas.

Psicologia, diretrizes curriculares e processos educativos na Amazônia: um estudo da formação de psicólogos

Este estudo objetiva analisar a formação de psicólogos frente às Diretrizes Curriculares Nacionais para os Cursos de Psicologia no que tange aos processos educativos. Realizamos revisão da literatura pertinente ao tema, pesquisa documental e empírica com alunos, professores e coordenador de curso, utilizando questionário, entrevistas e adotando a estratégia de triangulação a partir das categorias: perfil sociocultural; nível de conhecimento acerca das mudanças oriundas das Diretrizes para o curso de Psicologia; percepção na qualidade da prática docente; nível de satisfação com relação à própria formação universitária, tomando como referência os conhecimentos, habilidades e competências adquiridas. Apresenta contribuições para a compreensão da formação de psicólogos no campo da educação na Amazônia no Ensino Superior, centrada na construção de um profissional de pensamento e prática críticos, capaz de analisar as transformações nos vários contextos educacionais e escolares, utilizando referenciais que permitam a compreensão do fenômeno educativo na sua complexidade.

A expressão da modularidade

Desde Fodor (1983) a modularidade comportamental tem gerado fortes controvérsias, especialmente em torno do quanto são especializados os módulos eventuais e do quanto são encapsulados, isto é, independentes de controles externos. No presente ensaio, depois de rever formulações precursoras a respeito de instinto e de aprendizagens especializadas e de expor as características básicas da modularidade, tomo, como estudo de caso, pesquisas sobre a percepção da expressão facial da emoção, mostrando tanto o lado especializado desse processo como a sua abertura para controles externos. Termino defendendo a necessidade de, junto à estratégia de delimitar processos comportamentais especializados, colocar a questão de como eles se integram e se controlam uns aos outros e são eventualmente gerenciados por processos gerais.

Corporeidade e ação nos processos de formação do eu

Parte-se da hipótese de que tanto os modos de constituição da subjetividade, quanto as teses epistemológicas sobre a formação do eu têm sofrido importantes mudanças nas últimas décadas. No plano das identidades pessoais, tal fato se expressa no atenuamento do ideário intimista, tradicionalmente centrado na idéia da vida mental como espaço privado e interior. No plano epistemológico, diferentes saberes vêm questionando a equivalência entre vida mental e interioridade psicológica e propondo descrições da origem do eu que incluam a dimensão da corporeidade e da ação. Considerando as noções de representação e de ação como eixos fundamentais para diferentes concepções da subjetividade, este artigo examina um modelo internalista do psiquismo, contrastando-o com outro que toma o eu como agente corporificado.

Limites do cuidado: representações e processos inconscientes sobre a população na porta de entrada de um hospital de emergência

Este artigo apresenta parte dos resultados de uma investigação voltada para a análise dos limites e possibilidades que os processos intersubjetivos e inconscientes presentes nos serviços de saúde estabelecem para o exercício da solidariedade, para a cooperação e para a produção do cuidado com a vida. Elegeu-se como estudo de caso um hospital público de emergência, situado no Município do Rio de Janeiro, Brasil. A Psicossociologia francesa, de inspiração clínica psicanalítica, a teoria psicanalítica sobre os processos intersubjetivos e grupais e a Psicodinâmica do Trabalho são os referenciais centrais que orientaram o desenho da investigação e a análise do material empírico. As representações psíquicas e os processos inconscientes relativos à população e suas demandas, produzidos pelos trabalhadores de saúde do hospital estudado, foram analisados, discutindo-se suas conseqüências sobre a produção do cuidado. Algumas imagens se destacaram, como a "carência", utilizada como uma categoria encobridora da diversidade da demanda, num processo inconsciente de múltiplas reduções: da negação do sofrimento social à negação da condição de humanidade dos pacientes.

Novos paradigmas e velhos discursos: analisando processos de adolescentes em conflito com a lei

Este artigo evidencia análises contidas na dissertação cujo objetivo foi analisar os discursos dos operadores jurídico-sociais em processos judiciais de Varas da Infância e Juventude de duas cidades brasileiras. Os direitos das crianças e adolescentes, a questão social e a análise do discurso configuraram-se como referenciais teóricos e de análise. Resultados evidenciaram discursos de proteção e revelaram também a intenção de punição. A questão social foi ignorada pelos operadores a despeito dos contextos em que ocorreram as infrações.

Ácido clavulânico e cefamicina c: uma perspectiva da biossíntese, processos de isolamento e mecanismo de ação

The present article reviews different aspects of the chemistry of two widely used β-lactam antibiotics Clavulanic Acid and Cephamycin C. The article discusses important details of the biosynthesis of these compounds, their action mechanism and, principally, the methods employed in their isolation and purification, in accordance with the available literature. Despite the large quantity of available articles and patents concerning β-lactam antibiotics, those which describe the isolation and purification of Clavulanic Acid and Cephamycin C are rare. Overall, the intention of this article is to discuss the up-to-date scientific research related to the compounds under review.

Degradação de corantes ácidos por processos oxidativos avançados usando um reator com disco rotatório de baixa velocidade

Three technologies were tested (TiO2/UV, H2O2/UV, and TiO2/H2O2/UV) for the degradation and color removal of a 25 mg L-1 mixture of three acid dyes: Blue 9, Red 18, and Yellow 23. A low speed rotating disc reactor (20 rpm) and a H2O2 concentration of 2.5 mmol L-1 were used. The dyes did not significantly undergo photolysis, although they were all degraded by the studied advanced oxidation processes. With the TiO2/H2O2/UV process, a strong synergism was observed (color removal reached 100%). Pseudo first order kinetic constants were estimated for all processes, as well as the respective apparent photonic efficiencies.

Heterogeneidade de álcoois secundários em aguardentes brasileiras de diversas origens e processos de fabricação

Secondary alcohol concentrations in sugar cane spirits from different origins were determined by gas chromatography. A great variation in the concentration of the secondary alcohols was found in these spirits. Of the 33 brands analyzed, 8 of them were found to be out of conformity with the legislation. Sec butanol, for which the maximum allowed concentration level is 100 mg.L-1 in absolute ethanol, was found within a concentration range between 5 mg.L-1, the limit of quantitation (LQ) and 408 mg.L-1 in absolute ethanol. Sugar cane samples from Salinas, MG, were the only ones that exhibited self similarity because of the low concentrations of n-butanol and n-amylic alcohol (< limit of detection LD).

The Southern Brazilian shelf: general characteristics, quaternary evolution and sediment distribution

Extending from latitude 34ºS to 22ºS the Southern Brazilian shelf constitutes the only part of the Brazilian shelf with a subtropical to temperate environment. The studies on the different geological aspects of the area began in the 1960's and have recently been reassessed after studies related to the determination of the Economic Exclusive Zone. In terms of morphology, the Southern Brazilian shelf may be divided into three sectors, the São Paulo Bight, the Florianópolis-Mostardas Sector and the Rio Grande Cone, characterized by conspicuous differences in terms of geological determining factors, bathymetry, declivities and the presence of canyons and channels. Despite the existence of hundreds of radiocarbon datings the sea level changes curve of southern Brazil during the Last Glacial Cycle is still a matter of debate. A recent controversy on the Middle and late Holocene sea level changes curve raised the question of the amplitude of the oscillations which occurred in the period. Also, a few but relatively consistent radiocarbon datings suggest the occurrence of a high sea level during Isotope Stage 3. In terms of sedimentary cover the Southern Brazilian shelf exhibits a very strong hydrodynamic control, both latitudinal and bathymetrical. The sector southward from 25ºS is characterized by the influence of the plume of water carrying sediments originating from the Río de La Plata. Actually its presence is conspicuous up to 28ºS, with the area between this latitude and 25ºS constituting a transitional zone. In terms of bathymetry the outer shelf is marked by the "floor-polisher" effect of the Brazil Current, which is responsible for the maintenance of a relict facies in areas deeper than 100 meters.

Hydrodynamics and suspended sediment transport in the Camboriú estuary - Brazil: pre jetty conditions

Estuarine hydrodynamics is a key factor in the definition of the filtering capacity of an estuary and results from the interaction of the processes that control the inlet morphodynamics and those that are acting in the mixing of the water in the estuary. The hydrodynamics and suspended sediment transport in the Camboriú estuary were assessed by two field campaigns conducted in 1998 that covered both neap and spring tide conditions. The period measured represents the estuarine hydrodynamics and sediment transport prior to the construction of the jetty in 2003 and provides important background information for the Camboriú estuary. Each field campaign covered two complete tidal cycles with hourly measurements of currents, salinity, suspended sediment concentration and water level. Results show that the Camboriú estuary is partially mixed with the vertical structure varying as a function of the tidal range and tidal phase. The dynamic estuarine structure can be balanced between the stabilizing effects generated by the vertical density gradient, which produces buoyancy and stratification flows, and the turbulent effects generated by the vertical velocity gradient that generates vertical mixing. The main sediment source for the water column are the bottom sediments, periodically resuspended by the tidal currents. The advective salt and suspended sediment transport was different between neap and spring tides, being more complex at spring tide. The river discharge term was important under both tidal conditions. The tidal correlation term was also important, being dominant in the suspended sediment transport during the spring tide. The gravitational circulation and Stokes drift played a secondary role in the estuarine transport processes.