Biomedical subjects

G C Celotti

Publications and source records attributed to G C Celotti.

3 recordsLinked to original sources

PubMed1996

Mineral evolution of bone.

A study on the evolution with age of the mineral composition of bones was performed on samples belonging to human and other common mammalian species (cattle, sheep, dog). The study was carried out on the ashes obtained by calcination of the bone samples (1 h at 900 degrees C). The calcined powders were carefully examined by X-ray diffraction, from which precise quantitative evaluation (also confirmed by chemical analysis) of the crystalline phases present was derived. These data were analysed as a function of the introduced fractional age phi, a new relative scale that allows even largely different lifespan species to be compared. An overall linear increase in (Ca + Mg)/P ratio with log phi was found and the other considerations on molecular constitution (especially as regards Mg2+ substituting for Ca2+ in very young subjects) of the various phases detected were formulated and relative implications evaluated. The results appear promising for an improvement of knowledge in the field of biomedical experimentation and clinical implantology.

Absorptiometry, Photon↗

PubMed1995

Hydroxyapatite-based porous aggregates: physico-chemical nature, structure, texture and architecture.

At the request of medical teams from the maxillofacial sector, a highly porous ceramic support based on hydroxyapatite of around 70-80% porosity was produced with a pore size distribution similar to bone texture (< 10 microns, approximately 3 vol%; 10-150 microns, approximately 110 vol%; > 150 microns, approximately 86 vol%). The ceramic substrates were conceived not only as a fillers for bone cavities, but also for use as drug dispensers and as supports to host cells to produce particular therapeutic agents. A method is suggested to obtain a substrate of high porosity, exploiting the impregnation of spongy substrate with hydroxyapatite ceramic particles. X-ray and scanning electron microscopy analyses were carried out to evaluate the nature of the new ceramic support in comparison with the most common commercial product; pore size distribution and porosity were controlled to known hydroxyapatite ceramic architecture for the different possible uses.

Biocompatible Materials↗

PubMed1994

Granulates based on calcium phosphate with controlled morphology and porosity for medical applications: physico-chemical parameters and production technique.

Since the pore size distribution of a material in contact with bone is decisive for its type of link with the tissue, many granules are commercially available as fillers and as bone reconstructing materials. We propose a new technological procedure. The optimum architectural design for obtaining the most suitable link in vivo is investigated. Particular attention is attached to the granulate texture: micropores, macropores, total volume of pores, pore size distribution, and the morphology and shape of the pores. These characteristics are studied in order to obtain the best porosity for hydroxyapatite granulates now applied in vivo, with interesting results in mechanical and hard tissue linkage terms.

Biocompatible Materials↗