ANATOMICAL AND FUNCTIONAL STUDY OF THE MEDIAL COLLATERAL LIGAMENT COMPLEX OF THE ELBOW

Objective: To carry out an anatomical study of the medial collateral ligament, an important elbow stabilizer in different degrees of elbow flexion-extension. Methods: Forty elbows were dissected in order to analyze the functional behavior of the anterior, posterior and transverse ligament bands during valgus stress maneuvers of the elbow in different degrees of flexion and extension. Two groups were determined; in the group GPA the posterior band of the ligament was sectioned initially, then the articular capsule and finally the anterior band; in group GAP this order was reversed. Results: Instability was observed in GPA only in the third stage, when there was a greater mean elbow's opening during the flexion (between 50 degrees and 70 degrees); in GAP the instability was present since the first stage; the degrees of flexion with greater instability were the same as in group GPA. Conclusion: The anterior band of the medial collateral ligament of the elbow is the most important stabilizer of the elbow valgus instability, and its principal action occurs between 50 degrees and 70 degrees of elbow flexion. Level of Evidence III, Diagnostic Studies Investigating a diagnostic test.

Materials prepared from biopolyethylene and curaua fibers: Composites from biomass

Composites of high-density biopolyethylene (HDBPE) obtained from ethylene derived from sugarcane ethanol and curaua fibers were formed by first mixing in an internal mixer followed by thermopressing. Additionally, hydroxyl-terminated polybutadiene (LHPB), which is usually used as an impact modifier, was mainly used in this study as a compatibilizer agent. The fibers, HDBPE and LHPB were also compounded using an inter-meshing twin-screw extruder and, subsequently, injection molded. The presence of the curaua fibers enhanced some of the properties of the HDBPE, such as its flexural strength and storage modulus. SEM images showed that the addition of LHPB improved the adhesion of the fiber/matrix at the interface, which increased the impact strength of the composite. The higher shear experienced during processing probably led to a more homogeneous distribution of fibers, making the composite that was prepared through extruder/injection molding more resistant to impact than the composite processed by the internal mixer/thermopressing. (c) 2012 Elsevier Ltd. All rights reserved.

Macrophage Dectin-1 Expression Is Controlled by Leukotriene B-4 via a GM-CSF/PU.1 Axis

Pattern recognition receptors for fungi include dectin-1 and mannose receptor, and these mediate phagocytosis, as well as production of cytokines, reactive oxygen species, and the lipid mediator leukotriene B-4 (LTB4). The influence of G protein-coupled receptor ligands such as LTB4 on fungal pattern recognition receptor expression is unknown. In this study, we investigated the role of LTB4 signaling in dectin-1 expression and responsiveness in macrophages. Genetic and pharmacologic approaches showed that LTB4 production and signaling through its high-affinity G protein-coupled receptor leukotriene B4 receptor 1 (BLT1) direct dectin-1-dependent binding, ingestion, and cytokine production both in vitro and in vivo. Impaired responses to fungal glucans correlated with lower dectin-1 expression in macrophages from leukotriene (LT)- and BLT1-deficent mice than their wildtype counterparts. LTB4 increased the expression of the transcription factor responsible for dectin-1 expression, PU.1, and PU.1 small interfering RNA abolished LTB4-enhanced dectin-1 expression. GM-CSF controls PU.1 expression, and this cytokine was decreased in LT-deficient macrophages. Addition of GM-CSF to LT-deficient cells restored expression of dectin-1 and PU.1, as well as dectin-1 responsiveness. In addition, LTB4 effects on dectin-1, PU.1, and cytokine production were blunted in GM-CSF-/- macrophages. Our results identify LTB4-BLT1 signaling as an unrecognized controller of dectin-1 transcription via GM-CSF and PU.1 that is required for fungi-protective host responses. The Journal of Immunology, 2012, 189: 906-915.

Joint NOD2/RIPK2 Signaling Regulates IL-17 Axis and Contributes to the Development of Experimental Arthritis

Intracellular pattern recognition receptors such as the nucleotide-binding oligomerization domain (NOD)-like receptors family members are key for innate immune recognition of microbial infection and may play important roles in the development of inflammatory diseases, including rheumatic diseases. In this study, we evaluated the role of NOD1 and NOD2 on development of experimental arthritis. Ag-induced arthritis was generated in wild-type, NOD1(-/-)!, NOD2(-/-), or receptor-interacting serine-threonine kinase 2(-/-) (RIPK2(-/-)) immunized mice challenged intra-articularly with methylated BSA. Nociception was determined by electronic Von Frey test. Neutrophil recruitment and histopathological analysis of proteoglycan lost was evaluated in inflamed joints. Joint levels of inflammatory cytokine/chemokine were measured by ELISA. Cytokine (IL-6 and IL-23) and NOD2 expressions were determined in mice synovial tissue by RT-PCR. The NOD2(-/-) and RIPK2(-/-), but not NOD1(-/-), mice are protected from Ag-induced arthritis, which was characterized by a reduction in neutrophil recruitment, nociception, and cartilage degradation. NOD2/RIPK2 signaling impairment was associated with a reduction in proinflammatory cytokines and chemokines (TNF, IL-1 beta, and CXCL1/KC). IL-17 and IL-17 triggering cytokines (IL-6 and IL-23) were also reduced in the joint, but there is no difference in the percentage of CD4(+) IL-17(+) cells in the lymph node between arthritic wild-type and NOD2(-/-) mice. Altogether, these findings point to a pivotal role of the NOD2/RIPK2 signaling in the onset of experimental arthritis by triggering an IL-17-dependent joint immune response. Therefore, we could propose that NOD2 signaling is a target for the development of new therapies for the control of rheumatoid arthritis. The Journal of Immunology, 2012, 188: 5116-5122.

Novelty, but Not Operant Aversive Learning, Enhances Fos and Egr-1 Expression in the Medial Prefrontal Cortex and Hippocampal Areas of Rats

Immediate early genes (IEG) are presumed to be activated in response to stress, novelty, and learning. Evidence supports the involvement of prefrontal and hippocampal areas in stress and learning, but also in the detection of novel events. This study examined whether a previous experience with shocks changes the pattern of Fos and Egr-1 expression in the medial prefrontal cortex (mPFC), the hippocampal cornus ammonis 1 (CA1), and dentate gyrus (DG) of adult male Wistar rats that learned to escape in an operant aversive test. Subjects previously exposed to inescapable footshocks that learned to escape from Shocks were assigned to the treated group (EXP). Subjects from Group Novelty (NOV) rested undisturbed during treatment and also learned to escape in the test. The nonshock group (NSH) rested undisturbed in both sessions. Standard immunohistochemistry procedures were used to detect the proteins in brain sections. The results show that a previous experience with shocks changed the pattern of IEG expression, then demonstrating c-fos and egr-1 induction as experience-dependent events. Compared with NSH and EXP an enhanced Fos expression was detected in the mPFC and CA1 subfield of Group NOV, which also exhibited increased Egr-1 expression in the mPFC and DG in comparison to NSH. No differences were found in the DG for Fos, or in the CA1 for Egr-1. Novelty, and not the operant aversive escape learning, seems to have generated IEG induction. The results suggest novel stimuli as a possible confounding factor in studies on Fos and/or Egr-1 expression in aversive conditions.

Método de ensaio biomecânico para análise da isometricidade na reconstrução do ligamento patelofemoral medial

OBJETIVO: Apresentar um dispositivo biomecânico para o estudo da reconstrução do ligamento patelofemoral medial (LPFM) e sua isometricidade. MÉTODOS: Foi desenvolvido um sistema biomecânico acessível, que permite a aplicação de forças fisiológicas e não fisiológicas no joelho, através de um braço mecânico e aplicação de pesos e contrapesos, possibilitando a execução de diferentes estudos, além de ter um sistema de medidas bastante preciso de aferição de distâncias entre diferentes estruturas para análise dos experimentos. Este artigo descreve a montagem deste sistema, além de sugerir algumas aplicações práticas. Foram estudados seis joelhos de cadáveres. Os joelhos foram preparados em uma máquina de ensaios desenvolvida no Laboratório de Biomecânica do IOT HC FMUSP, que permitiu a avaliação dinâmica do comportamento patelar, quantificando a sua lateralização entre 0 e 120 graus. A diferença entre as distâncias encontradas, com e sem carga, aplicada na patela foram agrupadas segundo o ângulo de fixação do enxerto (0°, 30°, 60° e 90°) e situação do joelho (íntegro, reconstruído e lesado). RESULTADOS: Houve uma tendência em ocorrer menor desvio lateral em ângulos de fixação acima de 30 graus de flexão, principalmente entre os ângulos entre 45° e 60° graus de flexão, após a reconstrução. Para os demais ângulos não houve significância estatística. CONCLUSÃO: O método desenvolvido é uma ferramenta útil para os estudos da articulação patelofemoral, além de ter um sistema de medidas bastante preciso de aferição de distâncias entre diferentes estruturas e permitir a sua utilização em instituições com menos recursos disponíveis.

Estudo anatômico e funcional do complexo ligamentar colateral medial do cotovelo

OBJETIVO: Realizar um estudo anatômico do ligamento colateral medial, um importante estabilizador do cotovelo, em diferentes graus de flexo-extensão do cotovelo. MÉTODOS: Foram dissecados 40 cotovelos para analisar o comportamento funcional das bandas anterior, posterior e transversa do ligamento nas manobras de estresse em valgo do cotovelo durante seu movimento de flexão e extensão em diferentes graus. Determinou-se dois grupos: no GPA foi seccionado, a banda posterior do ligamento, depois a cápsula articular e, por fim, a banda anterior; no GAP, a ordem de dissecação foi inversa. RESULTADOS: No GPA observou-se instabilidade somente na terceira etapa e a média de abertura foi maior entre 50&º e 70&º de flexão de cotovelo; no GAP, a instabilidade apareceu desde a primeira etapa e os graus de flexão com maior instabilidade foram nos mesmos do grupo A. CONCLUSÃO: A banda anterior do ligamento colateral medial do cotovelo é o mais importante estabilizador na instabilidade em valgo do cotovelo e sua atuação principal acontece entre 50º e 70º de flexão do cotovelo. Nível de evidência III, Estudo Diagnóstico - Investigação de um exame para diagnóstico.

Análise do arco longitudinal medial em adolescentes usuárias de calçados de salto alto

O objetivo do estudo foi analisar a influência do calçado de salto alto no arco longitudinal medial (ALM) do pé de adolescentes. Fizeram parte do estudo 82 adolescentes entre 13 e 20 anos, sendo 54 não usuárias (grupo controle - GC) e 28 usuárias (grupo experimental - GE) de calçado de salto alto. Foram obtidas as impressões plantares de ambos os pés para análise do ALM, antes e depois do uso de um calçado de salto alto padronizado por um período de 30 minutos. As impressões plantares foram avaliadas pelo índice de Chippaux-Smirak (ICS) e pelo arco de Cavanagh & Rodgers (ICR). O teste de Shapiro-Wilks foi utilizado para a verificação da normalidade dos dados. Variáveis paramétricas pareadas foram tratadas com o Teste t de Student pareado e as não-paramétricas com o teste de Wilcoxon. As comparações não-pareadas foram realizadas com o teste t de Student para as variáveis paramétricas e o de Mann-Withney para as não-paramétricas, com nível de significância de 0,05. Houve diferença no ALM entre os lados direito e esquerdo apenas no GC antes do uso do calçado. Na comparação entre antes e depois do uso do sapato, notou-se diferença apenas no pé esquerdo do GC pelo ICS. Já entre GC e GE, não houve diferença. Apesar dos resultados não evidenciarem alterações no ALM, deve-se lembrar que esta é uma medida estática, sendo necessários estudos do componente dinâmico e do uso do calçado de salto crônico para correlacionar com os achados deste trabalho.