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Biomedical subjects

G Abatangelo

Publications and source records attributed to G Abatangelo.

At least 55 records · Page 3Linked to original sources
PubMed1981

Elastin and collagen in the normal and obstructed urinary bladder.

Histological and chemical studies were carried out on the elastin and collagen content of the normal and the obstructed urinary bladder wall. The observations were made on 3 different age groups: (1) 3-month-old children with vesical outlet obstruction, (2) children aged between 4 and 8 years with partial vesical obstruction, and (3) adults with a chronically obstructed bladder. An increase in elastic tissue was shown only in the newborn and in the adults. The collagen did not vary in any of the cases studied. The elastin showed an increase in polar amino acids in the pathological organs compared with the normal. A similar increase in elastin was observed in normal individuals as a result of the ageing process.

Aged↗
PubMed1978

Some observations on the calcium ion binding to the eggshell matrix.

The calcified matrix of the hen eggshell has been demineralized with the EDTA. Aliquots of this material are soluble in water and have been characterized by column chromatography and by chemical analyses. Of particular interest is the high hexosamine and uronic acid content, which confirms the protein-polysaccharide nature of this water-soluble material. The calcium ion binding to the eggshell matrix has been studied by the equilibrium dialysis technique at different pH values, with both free and blocked carboxylic groups. The material with the free carboxylic side chain groups binds more calcium ions with increasing pH value. When the carboxylic groups have been previously blocked with a water-soluble carbodiimide, the calcium ion binding rapidly decreases. The residual capacity to bind calcium ions in the material with the carboxylic functions modified is probably due to the sulfate ions. In agreement with previous observations on other calcified substrates, the calcium ion binding seems to depend on the presence of ionized carboxylic functions of the matrix.

Amino Acids↗
PubMed1978

Concentration-dependent conformational transition of alpha-elastin in aqueous solution.

Circular dichroism measurements on aqueous solutions of alpha-elastin have given evidence of beta-bend structure at elevated concentrations. When Ca2+ was added, the concentration-dependent conformational transition was somewhat inhibited and the binding of the metal ion was shown, by means of equilibrium dialysis, to be essentially independent from alpha-elastin concentration in the range of 1 to 10 mg/ml. The results obtained are discussed in connection with the elasticity and calcification of elastin.

Animals↗
PubMed1977

Conformational transitions of alpha-elastin.

The alpha-elastin, the soluble product obtained from elastin by oxalic acid hydrolysis, has been studied from a conformational point of view in different conditions using circular dichroism spectroscopy. The spectral variations of the alpha-elastin dissolved in water and in different organic solvents/water mixtures have been examined in order to establish the effect of the solvents on the structural properties of the protein. The effect of calcium ions has also been studied on alpha-elastin dissolved either in water or in organic solvents. Finally, the effect of pH and temperature on the conformational properties of the alpha-elastin has been investigated.

Animals↗
PubMed1977

The elastic tissue of the adult dilated ureter.

Adult dilated ureters have been examined in order to calculate the amount of the elastic tissue. From the histological observations and by the chemical analyses performed on the extracted elastin a decrease of the elastic tissue, as compared to the normal adult ureters has been noted. In fact, in the adult normal ureters, the elastin accounts for 9% of the dry matter, while in the abnormal the elastin represents 6.5%.

Adult↗
PubMed1976

The elastic component of normal and dilated ureters in children: chemical and histochemical characterisation.

Using chemical and histochemical techniques, it has been possible to calculate the exact amount and distribution of the elastin in normal and abnormal ureters in children. From the quantitative analyses, it has been calculated that in the dilated ureters the elastin content represents the 3% to 5% of the organic material, while in the normal ureters it is less than 1%.

Amino Acids↗
PubMedDate not supplied

In vitro reconstructed tissues on hyaluronan-based temporary scaffolding.

Tissue engineering offers the possibility to reconstruct tissue substitutes in order to replace lost or damaged tissues. The availability of appropriate biomaterial devices is essential to allow in vitro cultured cells to behave as in the original tissues in vivo. In our studies we utilized a seminatural biomaterial made up by the benzyl ester of hyaluronan to grow keratinocytes, fibroblasts and chondrocytes. Keratinocytes and fibroblasts were isolated from human foreskin. Cells were separately cultured on two different hyaluronan based biomaterial devices for the first 15 days and then co-cultured for an additional period of 2 weeks. Keratinocytes gave rise to a well-differentiated epithelial layer, while fibroblasts were able to synthesize all the main extracellular molecules inside the biomaterial spaces, forming dermal-like tissues. When these two tissues were co-cultured, a skin equivalent was formed with a dermal-epidermal junction. Chondrocytes were obtained from chick-embryo sterna and cultured for 21 days inside a non-woven scaffolding made up of a hyaluronan-based biomaterial. Cells were able to organize themselves into nodules embedded in a dense metachromatic substance in which type II collagen was present. Data from this study suggest that this novel class of hyaluronan derived biomaterials is suitable for different cell culture and in vitro tissue reconstruction.

Journal Article↗
PubMedDate not supplied

Functions of hyaluronan in wound repair.

Hyaluronan is a major carbohydrate component of the extracellular matrix and can be found in skin, joints, eyes and most other organs and tissues. It has a simple, repeated disaccharide linear copolymer structure that is completely conserved throughout a large span of the evolutionary tree, indicating a fundamental biological importance. Amongst extracellular matrix molecules, it has unique hygroscopic, rheological and viscoelastic properties. Hyaluronan binds to many other extracellular matrix molecules, binds specifically to cell bodies through cell surface receptors, and has a unique mode of synthesis in which the molecule is extruded immediately into the extracellular space upon formation. Through its complex interactions with matrix components and cells, hyaluronan has multifaceted roles in biology utilizing both its physicochemical and biological properties. These biological roles range from a purely structural function in the extracellular matrix to developmental regulation through effects of cellular behavior via control of the tissue macro- and microenvironments, as well as through direct receptor mediated effects on gene expression. Hyaluronan is also thought to have important biological roles in skin wound healing, by virtue of its presence in high amounts in skin. Hyaluronan content in skin is further elevated transiently in granulation tissue during the wound healing process. In this review, the general physicochemical and biological properties of hyaluronan, and how these properties may be utilized in the various processes of wound healing: inflammation, granulation and reepithelization, are presented.

Adjuvants, Immunologic↗