Glutamate and purine catabolites in relation to free radical production during focal ischemia-reperfusion : an in vivo study in cats

The in-vivo interrelation between excitotoxicity and oxidative stress following cerebral ischemia in cats was investigated. To elucidate the role of this mechanism in cerebral ischemia, the study presented herein sought to investigate the spatial and temporal features of the free radical response to elevations of glutamate and purine catabolites in a reproducible model of in vivo focal ischemia/reperfusion. The time course of neurochemical and Reactive Oxygen Species (ROS) were simultaneously conducted in ischemic focus and perifocal region of the brain.peer-reviewe

Nonverbal imitation skills in children with specific language delay

Research in children with language problems has focussed on verbal deficits, and we have less understanding of children's deficits with nonverbal sociocognitive skills which have been proposed to be important for language acquisition. This study was designed to investigate elicited nonverbal imitation in children with specific language delay (SLD). It is argued that difficulties in nonverbal imitation, which do not involve the processing of structural aspects of language, may be indicative of sociocognitive deficits. Participants were German-speaking typically developing children (n=60) and children with SLD (n=45) aged 2-3 ½ years. A novel battery of tasks measured their ability to imitate a range of nonverbal target acts that to a greater or lesser extent involve sociocognitive skills (body movements, instrumental acts on objects, pretend acts). Significant group differences were found for all body movement and pretend act tasks, but not for the instrumental act tasks. The poorer imitative performance of the SLD sample was not explained by motor or nonverbal cognitive skills. Thus, it appeared that the nature of the task affected children's imitation performance. It is argued that the ability to establish a sense of connectedness with the demonstrator was at the core of children's imitation difficulty in the SLD sample

Body movement imitation and early language as predictors of later social communication and language outcomes: A longitudinal study

Background and aims: Over recent decades much research has focused on detecting predictors of different language trajectories in children with early language delay but there has been very little exploration of social communication trajectories in these children. We report a longitudinal study that investigated the predictive value and clinical significance of elicited body movement imitation and language for later social communication and language outcome in Late Talkers. Methods: Participants were 29 German-speaking children who were identified with delayed onset and progression of language at two years and followed up at four years. Novel assessments of posture and gesture imitation were administered at Time 1, together with standardised language measures. All body movement imitation items involved self-other mappings, assumed to rely on sociocognitive capacities. At Time 2, children were assessed on standard language tests, together with parental reports of social communication. Results: Early language skills at Time 1 were significantly associated with later language outcome and body movement imitation skills at Time 1 with later social communication outcome. Logistic regression analyses revealed that body movement imitation as well as language at Time 1 added significantly to the prediction of language outcome at Time 2, whereas only body movement imitation made a significant contribution to the prediction of social communication outcome at Time 2. Conclusions and implications: Theoretically, results highlight the need to account for the heterogeneity of different language and communication trajectories in children with early language delay and point to the importance of sociocognitive difficulties observed in some of these children. Clinically, this study demonstrated that body movement imitation measures have the potential to improve the identification of pre-schoolers who are at risk of later social communication and language problems

Extreme magnesium isotope fractionation at outcrop scale records the mechanism and rate at which reaction fronts advance

Isotopic fractionation of cationic species during diffusive transport provides novel means of constraining the style and timing of metamorphic transformations. Here we document a major (~1‰) decrease in the Mg isotopic composition of the reaction front of an exhumed contact between rocks of subducted crust and serpentinite, in the Syros mélange zone. This isotopic perturbation extends over a notable length-scale (~1 m), implicating diffusion of Mg through an intergranular fluid network over a period of ~100 kyr. These novel observations confirm models of diffusion-controlled growth of reaction zones formed between rocks of contrasting compositions, such as found at the slab-mantle interface in subduction zones. The results also demonstrate that diffusive processes can result in exotic stable isotope compositions of major elements with implications for mantle xenoliths and complex intrusions

Substituição valvar cardíaca em ovinos – Descrição da técnica operatória e análise dos resultados

To evaluate the technical proceduresof a research protocol with tissue-engineered heartvalves in sheep, the surgical techniques for pulmonic,aortic and mitral valve replacement and the outcomeof 58 heart valve surgeries was analyzed. Thesheeps (age 18 ± 7 weeks and body weigh 30 ± 9.9kg) were implanted with valve bioprosthesis understandard protocols. Forty animals received pulmonicvalve prosthesis, fourteen animals received aorticprosthesis and four animals were implanted withmitral prosthesis. The fourth intercostal space wereconsidered the best for all operative techniques.The cardiopulmonary bypass (CPB) method throughcanulation of descending aorta and right atrial wereconsidered fast and secure. The CPB time of pulmonicvalve replacement was 34 ± 14 minutes and mortalityrate was 7,5%. The CPB time of subcoronarian aorticvalve implantation was 119 ± 5 minutes and themortality rate was 57%. In mitral substitution the CPBtime was 74 ± 22 minutes and mortality was 50%.The technique of pulmonic valve replacement wasvery efficient, however the mortality rate of both aorticand mitral valve surgery, associated with the highlysurgical technical complexity and elevated CPB time,require technical refinements to improve exploitationof the animals on the left side cardiac surgeries.Visando avaliar um protocolo experimentalde pesquisa com próteses valvares cardíacas emovinos, as técnicas cirúrgicas de substituição valvarpulmonar, aórtica e mitral de 58 cirurgias cardíacas foramanalisadas. Através de procedimentos padronizadosos ovinos (idade 18 ± 7 semanas e o peso 30 ± 9.9kg) foram submetidos ao implante de próteses valvaresbiológicas. Quarenta animais receberam prótesesvalvares pulmonares, 14 animais receberam prótesesaórticas e quatro animais receberam próteses mitrais.O quarto espaço inter-costal foi considerado de eleiçãopara realização das três técnicas operatórias avaliadas.O método de circulação extracorpórea (CPB)por canulação da aorta descendente e do átrio direitofoi considerado rápido e seguro. O tempo de CPB durantea substituição valvar pulmonar foi de 34 ± 14minutos e a mortalidade 7,5%. A substituição valvaraórtica, com implante subcoronariano, teve tempo deCPB 119 ± 5 minutos e mortalidade de 57%. Durantea substituição valvar mitral o tempo de CPB foi 74 ±22 minutos e mortalidade 50%. A técnica de implantevalvar pulmonar foi muito eficiente, entretanto a altamortalidade das técnicas de implante valvar aórtico emitral, associadas à maior complexidade cirúrgica eelevado tempo de CPB, faz necessário refinamentostécnicos para melhorar o aproveitamento dos animaisnas cirurgias das valvas cardíadas esquerdas

Observations of velocities, sand concentrations, and fluxes under velocity-asymmetric oscillatory flows

Peer reviewedPublisher PD