ABSTRACT
Cell migration is a crucial event in the general process of thymocyte differentiation. The cellular interactions involved in the control of this migration are beginning to be defined. At least chemokines and extracellular matrix proteins appear to be part of the game. Cells of the thymic microenvironment produce these two groups of molecules, whereas developing thymocytes express the corresponding receptors. Moreover, although chemokines and extracellular matrix can drive thymocyte migration per se, a combined role for these molecules appears to contribute to the resulting migration patterns of thymocytes in their various stages of differentiation. The dynamics of chemokine and extracellular matrix production and degradation is not yet well understood. However, matrix metalloproteinases are likely to play a role in the breakdown of intrathymic extracellular matrix contents. Thus, the physiological migration of thymocytes should be envisioned as a resulting vector of multiple, simultaneous and/or sequential stimuli involving chemokines, adhesive and de-adhesive extracellular matrix proteins, as well as matrix metalloproteinases. Accordingly, it is conceivable that any pathological change in any of these loops may result in the alteration of normal thymocyte migration. This seems to be the case in murine infection by the protozoan parasite Trypanosoma cruzi, the causative agent of Chagas' disease. A better knowledge of the physiological mechanisms governing thymocyte migration will provide new clues for designing therapeutic strategies targeting developing T cells
Subject(s)
Animals , Cell Movement , Chemokines , Extracellular Matrix , Integrins , T-Lymphocytes , Thymus Gland , Cell Adhesion , Cell Communication , Cell Differentiation , Thymus GlandABSTRACT
Thymocyte differentiation is the process by which bone marrow-derived precursors enter the thymus, proliferate, rearrange the genes and express the corresponding T cell receptors, and undergo positive and/or negative selection, ultimately yielding mature T cells that will represent the so-called T cell repertoire. This process occurs in the context of cell migration, whose cellular and molecular basis is still poorly understood. Kinetic studies favor the idea that these cells leave the organ in an ordered pattern, as if they were moving on a conveyor belt. We have recently proposed that extracellular matrix glycoproteins, such as fibronectin, laminin and type IV collagen, among others, produced by non-lymphoid cells both in the cortex and in the medulla, would constitute a macromolecular arrangement allowing differentiating thymocytes to migrate. Here we discuss the participation of both molecules with adhesive and de-adhesive properties in the intrathymic T cell migration. Functional experiments demonstrated that galectin-3, a soluble ß-galactoside-binding lectin secreted by thymic microenvironmental cells, is a likely candidate for de-adhesion proteins by decreasing thymocyte interaction with the thymic microenvironment
Subject(s)
Cell Adhesion Molecules , Cell Movement , Thymus Gland , Antigens, Differentiation , Cell Differentiation , Extracellular Matrix , Thymus Gland/cytologyABSTRACT
El politraumatismo es la principal causa de mortalidad en niños mayores de 1 año. Los scores de predicción de mortalidad en el politraumatismo constituyen índices de importancia para guiar las acciones terapéuticas y predecir el pronóstico. En el presente trabajo se estudio la capacidad predictiva de mortalidad de dos scores: ITP y MISS en 84 niños politraumatizados internados en la Unidad de Cuidados Intensivos del Hospital Harragan. El ITP con un punto de corte de 3 o menos demuestra una muy elevada especificidad y capacidad predictiva negativa asi como una adecuada sensibilidad. El MISS con punto de corte en 25 demostró alto valor predictivo negativo, pero menor capacidad predictiva positiva. El ITP constituye un recurso diagnóstico predictivo en el lugar del accidente para definir las acciones terapéuticas mientras que el MISS, aunque posee limitaciones puede emplearse en la evaluación de la gravedad en la Unidad de Cuidados Intensivos.
Subject(s)
Male , Female , Infant , Child, Preschool , Child , Adolescent , Wounds and Injuries/diagnosis , Predictive Value of Tests , Trauma Severity Indices , Retrospective StudiesABSTRACT
Los hallazgos del diagnóstico por imágenes, en un caso de epitelioma cuniculatum com recaída son comentados favorablemente. Creemos que estos medios deben recordarse en las patologías de similar comportamiento biológico y en casos problemas con la precaución debida a toda nueva técnica. En nuestro caso, la ecografía y la xeroradiografía fueron los métodos que aportaron los datos más valiosos
Subject(s)
Middle Aged , Humans , Male , Carcinoma , Foot Diseases , Skin Neoplasms , Carcinoma/pathology , Carcinoma/surgery , Recurrence , Tomography, X-Ray Computed , Ultrasonics , XeroradiographyABSTRACT
Sao apresentados dois casos de pseudomicetomas com diagnostico baseado em estudos bacteriologicos, histologicos e micologicos: a clinica sugeria tratarem-se de micetomas verdadeiros. Em ambos os casos foi isolado Staphylococcus aureus e, em ambos, existem antecedentes de traumatismo, o que confirmaria a porta de entrada do agente etiologico.Estes casos nos pareceram interessantes pela semelhanca clinica com micetomas verdadeiros e confirmando o conceito de micetoma como sindrome clinica ao inves de entidade nosologica