Ambivalent role of FasL in murine acute graft-versus-host-disease.

Fas ligand is increased in several immune-mediated diseases, including acute graft-versus-host disease, a donor cell-mediated disorder post-hematopoietic stem cell transplantation. In this disease, Fas ligand is involved in T-cell-mediated damage to host tissues. However, the role of its expression on donor non-T cells has, so far, never been addressed. Using a well-established CD4- and CD8-mediated graft-versus-host disease murine model, we found that precocious gut damage and mice mortality are increased with a graft of donor T- and B-depleted bone marrow cells devoid of Fas ligand as compared with their wild-type counterparts. Interestingly, serum levels of both soluble Fas ligand and IL-18 are drastically reduced in the recipients of Fas ligand-deficient grafts, indicating that soluble Fas ligand stems from donor bone marrow-derived cells. In addition, the correlation between the concentrations of these 2 cytokines suggests that IL-18 production arises through a soluble Fas ligand-driven mechanism. These data highlight the importance of Fas ligand-dependent production in IL-18 production and in mitigating acute graft-versus-host disease. Overall, our data reveal the functional duality of Fas ligand according to its source.

Chain length effect on the structure and stability of antimicrobial peptides of the (RW)n series.

Three peptides containing (RW)n-NH2 units (where n=4, 6, and 8) have been chosen to study the effect of the chain length on the structure and stability of the peptide using Fourier transform infrared (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) techniques. Their interactions with Escherichia coli (E. coli) membrane mimetic vesicles are discussed. Infrared results indicate that addition of (RW)n-NH2 units increases intermolecular H bonds with antiparallel orientation. TGA and DSC results reveal that (RW)6-NH2 shows the optimal chain length in terms of stability and all three peptides show a preferential interaction with one of the anionic lipids in E. coli membranes. SEM images of (RW)4-NH2 present large aggregates while those of (RW)6-NH2 and (RW)8-NH2 present layers of sheet-like structure. In the presence of model membranes, (RW)n-NH2 show fibrillar peptide superstructures. This study suggests that repeating structures of (RW)n-NH2 promotes lateral assembly.

Asertividad y consumo de drogas en estudiantes mexicanos / Assertiveness and drug use among Mexican students / Assertividade e consumo de drogas em estudantes mexicanos

El estudio persiguió evaluar la relación entre una baja asertividad y el uso de drogas ilícitas entre estudiantes mexicanos, así como identificar si alguna de las características asertivas como control conductual, reconocimiento y aceptación de los demás, enfrentamiento eficaz de los problemas y diferencias interpersonales, percepción de autoeficacia en la resolución de problemas, habilidades en la expresión verbal y afectos positivos asociados al enfrentamiento de problemas, predicen probabilísticamente el consumo de drogas ilícitas. Se utilizó un diseño no experimental, transversal, ex post facto, y con un muestreo por conveniencia, se encuestó a 1.492 estudiantes de escuelas secundarias localizadas en zonas de alto riesgo para el consumo de drogas utilizando la escala de Evaluación de Factores Asertivos (EFA), validada en población mexicana adolescente. De los estudiantes participantes se conformaron dos grupos: el de Usuarios de drogas ilícitas y el de No usuarios de drogas. Al comparar las características asertivas entre ambos grupos, se encontró que los No usuarios cuentan con estrategias de enfrentamiento más eficaces a los problemas, perciben mayor autoeficacia en su resolución, tienen mayor control conductual, mayor reconocimiento y aceptación de los demás, presentan más habilidades de expresión verbal y tienen un mejor manejo de sus afectos. Asimismo, se identificó mediante un análisis de regresión logística que el control conductual y el reconocimiento y aceptación de los demás son elementos con mayor probabilidad de fungir como elementos protectores del consumo de drogas ilícitas. Los hallazgos confirman la relevancia de las habilidades comunicativas, el control de impulsos y el manejo de emociones, para el establecimiento de relaciones más satisfactorias y en el enfrentamiento ante la oferta de tabaco, alcohol u otras drogas.

The aim of this study was to assess the relationship between low assertiveness and illicit drug use among high school students, and to determine which of the assertive characteristics such as behavioral control, recognition and acceptance of others, effective coping with problems and interpersonal differences, perceived self-efficacy in problem solving, verbal expression skills and positive affect in dealing with problems, acted as predictors of consumption. The research used a non- experimental cross-sectional and ex post facto design. By means of a non-probabilistic sampling technique, 1492 high school students were selected from schools located in high risk areas for drug consumption and were surveyed through the Assertive Factors Assessment Scale [EFA for its Spanish acronym], validated with Mexican adolescent population. The students were divided in two groups, the Illicit Drug users and the Non-drug users. After comparing the assertive characteristics between both groups, it was found that Non-drug users have more effective strategies for coping with problems, a perception of higher self-efficacy in solving problems, higher behavioral control, greater recognition and acceptance of others, better verbal expression skills and a more effective emotional management. It also found by logistic regression analysis that behavioral control and recognition and acceptance of others were factors most likely to serve as protective factors of illicit drug use. Results confirm the importance of communication skills, impulse control and emotional management for establishing more satisfying relationships and coping with access to tobacco, alcohol or illicit drugs.

O estudo buscou avaliar a relação entre uma baixa assertividade e o uso de drogas ilícitas entre estudantes mexicanos; assim como identificar se alguma das características assertivas como controle da conduta, reconhecimento e aceitação dos outros, enfrentamento eficaz dos problemas e diferença interpessoais, percepção de auto eficácia na solução de problemas, habilidades na expressão verbal e afetos positivos associados ao enfrentamento de problemas, predizem probabilisticamente o consumo de drogas ilícitas. Através de um desenho não experimental, transversal, ex post facto, e com uma amostragem por conveniência, foram entrevistados 1.492 estudantes de escolas secundárias localizadas em zonas de alto risco para o consumo de drogas utilizando a escala de Avaliação de Fatores Assertivos (EFA), validada na população mexicana adolescente. Dos estudantes participantes foram formados dois grupos, o de Usuários de drogas ilícitas e o de Não usuários de drogas. Ao comparar as características assertivas entre os grupos, encontrou-se que os Não usuários contam com estratégias de enfrentamento mais eficazes aos problemas, percebem maior auto eficácia em sua resolução, têm maior controle de conduta, maior reconhecimento e aceitação dos outros, apresentam mais habilidades de expressão verbal e têm um melhor controle de seus afetos. Da mesma forma identificou-se mediante uma análise de regressão logística que o controle de conduta e o reconhecimento e aceitação dos outros são elementos com maior probabilidade de atuar como elementos protetores do consumo de drogas ilícitas. Os descobrimentos confirmam a relevância das habilidades comunicativas, o controle de impulsos e o controle das emoções, para o estabelecimento de relações mais satisfatórias e no enfrentamento diante da oferta de tabaco, álcool ou outras drogas.