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Biomedical subjects

R Cortivo

Publications and source records attributed to R Cortivo.

11 recordsLinked to original sources
PubMed1991

In vitro studies on biocompatibility of hyaluronic acid esters.

The biocompatibility of semisynthetic polymers formed from hyaluronic acid esters has been studied using fibroblast cultures. The polymers, added to the culture medium, used either in powdered form or as thin membranes, behave as inert materials. The cells used in the experiments grow normally in the culture dishes. With regard to adhesiveness the cells were not able to spread on the biomembranes and tended to form isolated clusters of round cells. Human fibronectin, placental collagen (type I-IV) and fibrin could be stratified on biomembranes. When these molecules reacted with the biomaterial the film became suitable for fibroblasts spreading and growth.

Animals↗
PubMed1990

Hyaluronic acid promotes chick embryo fibroblast and chondroblast expression.

15-day-chick-embryo fibroblasts and chondroblasts were cultured in the presence of high and low molecular weight exogenous hyaluronic acid (HA). Growth range and incorporation of radiolabelled sulphate and proline were determined. HA reduced cell proliferation to about 75% of controls, while incorporation of radiolabelled sulphate and proline was higher in HA-treated cultures of both chondroblasts and fibroblasts. The effect was not due to the polyanionic or polymeric nature of the molecule and appeared to be highly specific for HA.

Animals↗
PubMed1989

Intraarticular sodium hyaluronate injections in the Pond-Nuki experimental model of osteoarthritis in dogs. II. Morphological findings.

The effect of the intraarticular sodium hyaluronate (HA) injection on the osteoarthritic knee joint has been evaluated in dogs using an experimental model of osteoarthritis induced by sectioning the anterior cruciate ligament. Seven weeks after surgery, the damage, graded according to Mankin's scale, was significantly reduced in knee joints treated with HA from the second week postsurgery compared to untreated joints. When intraarticular HA therapy was initiated after the seventh week, osteoarthritis progression was still reduced compared to controls. Both morphology and morphometry showed a beneficial effect of HA on the cartilage response to the damage, as well as a clearcut inhibitory effect on the development of the fibroblastlike cell layer on the articular cartilage in untreated joints. The beneficial effects on the cartilage integrity and response to osteoarthritic damage might be related to a primary effect of HA on the cartilage surface. However, these effects do not exclude the possibility that, in addition, HA might act on the synovial membrane by limiting the synovial reaction.

Animals↗
PubMed1989

Intraarticular sodium hyaluronate injections in the Pond-Nuki experimental model of osteoarthritis in dogs. I. Biochemical results.

An established anterior cruciate ligament deficiency-induced articular cartilage degeneration was used to evaluate the effects of intrasynovial injection of hyaluronic acid upon cartilage destruction. In this study, proteoglycan solubility under associative and dissociative conditions was compared in two treatment protocols at intervals of seven, 13, and 17 weeks after surgical breakage of the anterior cruciate ligament in 2.5-year-old Beagle dogs. Untreated joints showed a marked increase in both total soluble glycosaminoglycan (GAG measured as uronic acid) and in the associative fraction. In both treated groups, there was a reduced amount of soluble GAG. Cessation of treatment after seven weeks caused gradual regression, with an increasing amount of CaCl2-soluble material in the associative fraction, while inception at seven weeks gave biochemical evidence of reversal, with increasing GAG present in the guanidine-soluble (dissociative) fraction on the insoluble residue. The protective effects of hyaluronic acid suggest the potential clinical application of this therapy in retarding the advance of osteoarthritis.

Animals↗
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↗
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↗