The availability of antisera against collagen and non-collagen proteins of the extracellular matrix has opened new possibilities of studying fibrous infiltration in muscular diseases. We have examined muscle biopsies from 5 controls and 27 patients with various neuromuscular diseases by immunofluorescence and peroxidase-anti-peroxidase. We investigated the distribution of fibronectin and of laminin, a protein present in basement membranes. In normal muscle both were present around blood vessels, axons, muscle spindles and muscle fibres. In addition fibronectin filled the endomysial and perimysial space, the endoneurium and the space between the intrafusal fibres. In pathological muscle laminin distribution was similar to that in normal muscle, but some atrophic fibres appeared to have a thickened contour and irregular profiles were occasionally observed in the absence of histologically demonstrable muscle fibres. Fibronectin was increased in all the conditions with thickened endomysium and perimysium, without displaying any disease-specific character. Findings are compared with the few published observations on fibronectin and collagen types.

Connective Tissue↗

PubMedDate not supplied

[Increase of fibronectin-dependent phagocytosis by immune interferon of the mouse].

In the present study we have investigated the capability of IFN-gamma to increase the Mac fibronectin-dependent phagocytosis. We demonstrate that IFN-gamma (50 U/ml) induces an increase of phagocytosis by elicited (PP-Mac), but not by normal Mac (R-Mac) when latex-beads particles are coated with gelatin.

Animals↗

PubMedDate not supplied

Localization of the alpha 3 beta 1 integrin in some common epithelial tumors of the ovary and in normal equivalents.

Monoclonal antibodies (mAbs) against cultured human ovary carcinoma cells were produced. We obtained 7 mAbs which reacted diffusely with carcinoma of the ovary but only weakly with vessels and the surface epithelial layer of normal ovary. Biochemical characterization of these mAbs indicated that 3 out of 7 were specific for the alpha 3 chain of the Vla-3 integrin, a receptor for fibronectin, collagen and laminin. Using one of these mAbs, we have studied, by immunohistochemical methods, the distribution of alpha 3 beta 1 integrin in mucinous, serous and endometrioid cystoadenocarcinoma of the ovary and in their normal equivalent: endocervical, tubal and endometrial epithelia. The results show that alpha 3 beta 1 is present in cell-cell contact areas and more abundantly at the junction between epithelial cells and basement membrane in endocervical, tubal epithelia, in epithelium lining the cavity of the uterus and in surface epithelium of the ovary. However, endometrial glands showed only weak and fragmented positivity at the basal pole of the cells. 26 out of 31 ovarian cancers studied, expressed the alpha 3 beta 1 integrin. However, basal localization, typical of normal epithelia, is not prominent or disappears in tumors and is replaced by a more diffuse reaction with variable immunohistochemical staining of the neoplastic cells. Furthermore, a comparative analysis of the expression of alpha 3 beta 1 and its ligands, laminin (LM), fibronectin (FN) and collagen IV (Coll IV), demonstrated that basal polarization of Vla-3 was always correlated with the presence of laminin and Coll IV, intrinsic components of the basement membranes.

Amino Acid Sequence↗