RESUMEN
By immunohistochemistry, we studied the breakdown of type I collagen in frozen sections of normal and hyperplastic (myasthenia gravis-associated) human thymuses. This analysis was carried out using a specific polyclonal antibody directed against the alpha 2-CB(3,5) peptide, a degradation product of type I collagen. In the normal thymus, virtually no labeling was observed within thymic septae or intralobular regions. In contrast, bright fluorescent staining was consistently detected in myasthenia gravis-associated hyperplastic thymuses. Such immunoreactivity was found not only in septal regions but also in the intralobular connective tissue meshwork that exists in these thymuses. Our results represent further evidence for a defect in extracellular matrix metabolism in hyperplastic thymuses, which may be related to the abnormal intrathymic penetration of B cells, known to occur in this disease.
Asunto(s)
Colágeno/metabolismo , Matriz Extracelular/metabolismo , Miastenia Gravis/metabolismo , Timo/metabolismo , Adolescente , Adulto , Preescolar , Colágeno/clasificación , Humanos , Hiperplasia , Inmunohistoquímica , Lactante , Miastenia Gravis/patología , Valores de Referencia , Timo/patologíaRESUMEN
The distribution and synthesis of type I and type III collagens in the mouse molar tooth root have been investigated by correlating light and electron immunohistochemical data. Purified rabbit antibodies were raised against mouse type I and type III collagens and indirect immunoperoxidase procedures were used. In these conditions, predentin, pre-bone, and pre-acellular cementum were intensely immunostained for type I collagen. Both optic and ultrastructural data confirmed the presence of type I collagen at the epithelio-mesenchymal junction, but Hertwig's basement membranes remained unlabelled. The odontoblasts including the short polarized ones, osteoblasts, some cells of pulp mesenchyme and the perifollicular cells possessed type I collagen immunoreactivity in the rough endoplasmic reticulum (RER), Golgi complex and the secretory vesicles. Type III collagen immunoreactivity was strong in the perifollicular mesenchyme, light in the pulp mesenchyme and absent from the epithelio-mesenchymal junction, the predentin, pre-bone and pre-acellular cementum. Intracellular immunolabelling was detected at the ultrastructural level in the perifollicular cells by a faint homogeneous peroxidase deposit in the RER cisternae. Finally, these results, compared with previous biochemical and morphological data, represent the first dynamic aspect of collagens distribution and synthesis in the mouse molar root development. In terms of cell differentiation, our data also suggest that type III collagen synthesis does not occur during the odontoblast process of differentiation.