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Biomedical subjects

C Fornieri

Publications and source records attributed to C Fornieri.

26 records · Page 2Linked to original sources
PubMed1984

Elastin fiber-associated glycosaminoglycans in beta-aminopropionitrile-induced lathyrism.

Ruthenium red and toluidine blue O precipitates were described associated with lathyritic elastic fibers in aortas of chickens treated with beta-aminopropionitrile fumarate (I. Pasquali-Ronchetti, C. Fornieri, I. Castellani, G. M. Bressan, and D. Volpin (1981). Alterations of the connective tissue components induced by beta-aminopropionitrile. Exp. Mol. Pathol. 35, 42-56). In this report evidence is given that these precipitates reveal the presence of proteoglycans, as they are completely removed by 5 M guanidine-HCl incubation and by specific enzymatic digestions. In particular, proteoglycans associated with the poorly cross-linked lathyritic elastin can be removed by testicular hyaluronidase, chondroitinase ABC, heparitinase, and nitrous acid treatments, whereas they are rather resistant to streptococcal hyaluronidase and chondroitinase AC. On the contrary, proteoglycans of the matrix or associated with collagen fibers are particularly sensitive to these latter enzymatic treatments. The conclusion is reached that glycosaminoglycans associated with beta-aminopropionitrile-induced lathyritic elastin (i) are different from those of the matrix or associated with collagen, and (ii) include mainly dermatan and heparan sulfates.

Aminopropionitrile↗
PubMed1983

Banded fibers in tropoelastin coacervates at physiological temperatures.

Tropoelastin was purified from aortas of chicks grown on a beta-aminopropionitrile-containing diet. The preparation could be considered pure following the criteria of amino acid composition and gel electrophoresis. When aqueous solutions of tropoelastin (5 mg/ml) were warmed to 40 degrees C (physiological temperature for chicken) for 10 min, and observed by negative-staining electron microscopy, it revealed the presence of two kinds of ordered structures. One consisted of densely packed parallel filaments with a center-to-center distance of about 5 nm, and the other of banded fibers, 100-150 nm in diameter, with a cross periodicity of about 55 nm. In some areas the fibers appeared to be formed by lateral aggregation of 1.5-2-nm-thick microfilaments. The fibers were similar to those previously obtained with the synthetic polypentapeptide of elastin (Val-Pro-Gly-Val-Gly)n and degradation products of elastin at temperatures much higher than the physiological one. The results indicate that the property of tropoelastin to form ordered structures is intrinsic to some of the polypeptide sequences of the molecule and that hydrophobic forces are involved in the formation of the aggregates.

Amino Acids↗
PubMed1982

Contribution of cryotechniques to the study of elastin ultrastructure.

Cryomethods were used in order to investigate the ultrastructure of native elastin fibres from beef ligamentum nuchae. Filaments of diameter 5 nm, running almost in parallel in purified, negatively-stained elastin preparations, were also seen running along the elastin fibre both in freeze-fractured and etched elastin, that had been stretched up to 200%, and in cryo-sectioned elastin that had been stretched and chemically fixed before freezing. Interconnections between elastin filaments were revealed by the freeze-etching technique. Glycerol treatment, which probably leads to hydration of specimens, resulted, however, in disorganization of filaments and swelling of the elastin fibre. In conclusion, by the use of cryotechniques, it was convincingly demonstrated that elastin molecules are arranged in long interconnecting filaments of about 4-5 nm width.

Animals↗
PubMed1980

Ultrastructural and biochemical changes induced by progressive lipid peroxidation on isolated microsomes and rat liver endoplasmic reticulum.

Ultrastructural and biochemical alterations induced by progressive lipid peroxidation on rat liver endoplasmic reticulum and on isolated microsomes have been studied. Lipid peroxidation was followed by measuring the content of malonaldehyde and similar thiobarbituric acid-reacting substances in the control specimens and in specimens in which lipid peroxidation was stimulated by CCl4 or other prooxidant systems. Lipid peroxidation induced a remarkable decrease in aminopyrine demethylase activity and in the cytochrome P-450 content both in vivo and in vitro. Parallel to these observations, alterations in the assembly of the membranes of isolated rat liver microsomes and of in situ endoplasmic reticulum were followed by electron spin resonance and electron microscopy. Electron spin resonance revealed changes in the resonance spectra interpreted as solubilization of cytochrome P-450 from the membrane. Electron microscopy on fixed and sectioned, negatively stained and freeze-fractured specimens revealed membrane alterations that were progressive with time of peroxidation. These alterations consisted of: (1) increased membrane deformability; (2) local and progressive breakages on the membranes; and (3) loss of intramembranous particles on both fracture faces of the membranes. The results obtained with the different techniques are compared and discussed in light of the importance of the lipid environment for the structure and function of biologic membranes.

Aminopyrine N-Demethylase↗