M. Th. Pieraggi

Solid-state studies on synthetic fragments and analogues of elastin

A series of synthetic fragments and analogues of elastin have been investigated, in the solid state, by means of differential scanning calorimetry and thermally stimulated current. Most of the polypeptides were shown to possess both amorphous regions and segments of long-range order. Water, which interacts preferentially with the amorphous zones, behaves as plasticizer, i.e. facilitates the localized motions of polypeptide chains. The results obtained have been correlated with elastin elasticity, in particular as far as the fundamental destructuring role of water is concerned.

Striae: Morphological aspects of connective tissue

The study of 15 abdominal striae in women aged 25 to 57 shows important histological modifications in the skin. The collagen is fragmented and the ground substance is abundant. Fibroblasts are globular, quiescent, and lose all signs of fibrillar secretion. In the light of the recent biochemical data, our results suggest that the striae are the consequence of fibroblastic dysfunction, due to abdominal distension. Comparison with scarred and normal skin indicate that striae are a special entity belonging to the group of connective dystrophies.

Fine structural evidence of increased endothelial permeability in chronic lathyrism

The endothelium of the thoracic aorta of Wistar rats intoxicated with Beta-Aminopropionitrile (BAPN) for 9 weeks was studied. The animals were sacrificed at intervals, from the first to the 9th week of the treatment and 1, 2 and 3 months after the end of the treatment. Changes in the endothelial cells were studied by electron microscopy after staining with uranyl acetate and lead citrate, after impregnation with lanthanum. BAPN increased endothelial permeability, pinocytosis was more active in treated rats than controls, the intercellular junctions widened and cytoplasmic lesions with cell necrosis occurred. These intimal changes were comparable to those observed in man during ageing and in arteriosclerosis.

Chronic lathyrism and atheromatosis in the rat

Temporary chronic administration of Beta-amino-propionitrile (B.A.P.N.) produced morphological and biochemical changes of the aortic wall of rat as well as abnormalities of the plasma lipid levels. A hyperlipidic diet resulted in the blood plasma lipid abnormalities as B.A.P.N. intoxication. Nine weeks of B.A.P.N. followed by 42 weeks of a hyperlipidic diet increased the aortic cholesterol level and induced an atheroma. The diet alone produced only an endothelial lipid overload. The structure of arterial wall played the decisive role in atherogenesis.

Skin cholesterol in ageing rats and experimental atheroma.

Summary The present experiments have shown the following: 1) The levels of skin cholesterol in the rat, like man, are related to age of the animal and to hyperlipoproteinaemia. 2) In experimental atheroma (BAPN : lg/Kg/day and a high fat diet) no relationship exists between the degree of atheroma and the levels of skin cholesterol, in contrast to the situation in man.

Long term lathyrism and atherogenic diet in the rat

In the rat, prolonged administration (7 months) of Beta-Amino-propionitrile in association with a hyperlipidic diet caused the formation of widespread pronounced atheroma. The addition of Pyridinol Carbamate during the treatment minimized and retarded the appearance of lipid overload lesions. The histological modifications were found together with an increase in the free cholesterol fraction. These two observations explain the protective role of Pyridinol Carbamate on the wall of the aorta.

TSC study of collagen as a function of aging

The dielectric relaxation modes observed in collagen from −200 to +150°C are strongly related to water content and maturation.

Chronic lathyrism and pyridinol carbamate. Study of aorta and plasma during long term intoxication.

Summary The action of Pyridinol Carbamate is studied in the rat during long term Beta-aminopropionitrile treatment, histologically and through plasma and aorta cholesterol assay. PDC reduces the severity of elastic lesions due to BAPN but does not seem to have any effect on the levels of cholesterol of either aorta or plasma.