[Fibrocytes and activated fibrocytes in the healing of an open skin wound].

The microscopic, electron microscopic and immunohistochemical observation of biopsy specimens taken at an early stage, at close and regular intervals (every 4 hours), from open skin wounds created in the pig and the monkey, together with quantitative analysis of the various cell types in the granulation tissue, supports the conception that the activated fibrocyte (fibroblast) originates from the fibrocyte of the wound edges and thus completes some earlier experimental studies. We describe here the various stages of the differentiation of the wound edge fibrocyte into an activated fibrocyte and its proliferation and migration from the edges to the site of the wound. This does not exclude the possibility that local mesenchymal cells take part in the formation of activated fibrocytes.

An atypical aortic atherosclerotic lesion in cynomolgus monkeys during hypercholesterolemia: a protection by smooth muscle cells against advanced lesions?

This study focuses on the fortuitous discovery of an atypical atherosclerotic lesion in four of 49 male adult cynomolgus monkeys (macacus fascicularis) which were maintained for a long time at a high level of hypercholesterolemia, and in seven of 19 female cynomolgus monkeys examined from the second to the 24th week of hypercholesterolemic diet: this lesion was in formation or already mature during this period of diet. This atypical lesion was formed by a collagen and elastic network surrounding synthetic smooth muscle cells without fibrofatty or fibrous plaques. Lipids were occasionally seen in the inner intima.

[Non-atherosclerotic aorta in Cynomolgus after a hypercholesterolemic regimen].

The authors present a study on atherosclerotic and non atherosclerotic lesions of aortas of Cynomolgus (Macaca Fascicularis) on high fat diet (HFD) (6-12-24 months), after regression and after resumption. At 6 months 2 aortic responses are seen: an edema, deep and superficial clumps of foam cells, few synthetic smooth muscle cells (SSMC) few collagenic fibers--an edema, few superficial foam cells, many SSMC, secreting collagen and elastin. At 12-24 months, after regression and resumption, two aortic lesions are observed: a pronounced atheroma (47 animals) and no atheroma (14 animals).

Optimization of a model of full-thickness epidermal burns in the pig and immunohistochemical study of epidermodermal junction regeneration during burn healing.

In order to obtain a wound model in which healing involved epidermis rebuilding and epidermodermal junction (EDJ) regeneration without involvement of any dermal repair, we optimized a previous model of experimental cutaneous burning with an aluminum bar by testing various conditions of burning associated with different pre- and postburn skin treatments. On the optimized model of full-thickness epidermal burns without any dermal injury, we investigated the kinetics of regeneration of 4 EDJ components, from day 2 to day 23 after burning. The epidermal healing was studied by light microscopy and EDJ regeneration by indirect immunofluorescence with one bullous pemphigoid (BP) serum, antisera to fibronectin and to type IV collagen (Coll IV) and the monoclonal antibody 4C 12-8 to laminin.

[Collagens of the internal saphenous vein, normal and varicose, as a function of age].

The normal venous vein contains more collagen in the young subject than in the ageing subject. This is confirmed by the decrease of thickness of aged venous wall indicating that the fibrosis present in the aged subject is atrophic in nature. Collagen content of the varicose vein wall remains practically unchanged with age: the varicose vein is a dysplasic vein.