Peripheral lymphoid organs have two groups of non lymphoid cells: that of macrophages which belongs to R. van Furth's system of mononuclear phagocytes and the one made of elements for long labelled "reticular cells". The use of electron microscopy has permitted a good understanding of these elements and a recognition of ubiquitous cells (fibroblasts, endothelial cells) and specific cells to the lymph node which seem to play a very important role in the immune reactions (interdigitated cells, reticulum cells, dendritic cells). We describe their light and electron microscopical features and histoenzymatic characters, and present the actual concept of their origin and function. The latest discoveries on their classification are reviewed and have permitted to distinguish three categories of non lymphoid cells: first the group of reticulum cells (reticulum cells and dendritic cells), second that of mononuclear phagocytes (macrophages and interdigitated cells) and third that of endothelial cells. Other elements of questionable existence or insufficiently known do not appear in this classification: dark cells, Steinman and Cohn's dendritic cells and cells containing Birbeck's granules.

Animals↗

PubMedDate not supplied

[Ultrastructural aspects of a cutaneous biopsy in acquired immune deficiency syndrome (AIDS)].

Herpes zoster blister was biopsied in an homosexual man presenting and AIDS. Ultrastructural findings were as follows: typical herpes virus particles, tubuloreticular inclusions (TRI), helical polyribosomes. The association of these three findings suggests that TRI may represent rather a particular way of cellular reaction than an etiologic ultrastructural marker in AIDS.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

An immunohistochemical study of P53 protein on colorectal carcinomas.

AIMS: To investigate the frequency of immunohistochemical expression of p53 protein in colorectal carcinomas; to evaluate the correlation between p53 alterations and the histopathological parameters; to determine the prognostic significance of this tumor marker. PATIENT POPULATIONS: Fourty patients with colorectal carcinomas. METHODS: Paraffin embedded normal and tumoral tissues, stained, with HES, PAS, PAS-Alcian Blue stains. For detecting the p53 protein, a three step (streptavidin-biotin immunoperoxidase) immunohistochemical method was used. RESULTS: 28 out of 40 (70%) colorectal carcinomas were positive for p53. The identification of nuclear accumulations of p53 protein in the present study was significantly correlated with the anatomic site and tumor stage. CONCLUSIONS: The mutational pattern observed in this study was substantially as expected. The p53 overexpression is present in advanced stage, thus demonstrating the prognostic value of this marker.

Adenocarcinoma↗

PubMedDate not supplied

[Pulmonary actinobacterioses. Apropos of a case].

Explore the source record for details and available documents.

Actinomycosis↗