[Calcium release from the mineral matrix of the mandibular bone due to hydrogen peroxide exposure]. / Rilascio di calcio della matrice minerale di osso mandibolare mediante esposizione a perossido di idrogeno.

The purpose of this paper is to quantify by in vitro experiment free radical activity in jaw bone demineralization processes. Sample were take and graphic interpolation of calcium ions undertake. The significance of the results is compared with the paper that are published in literature on the same subject.

[DNA extraction from hard dental tissues]. / Estrazione di DNA dai tessuti duri del dente.

Two different standard ways of DNA extraction (salting out and phenol-chloroform methods) were assayed in order to recovery nucleic acids from dental tissues. The DNA extracted was tested for purity by means of transverse alternating field electrophoresis (TAFE) using Saccharomyces cerevisiae chromosomes as markers. Both extraction methods give similar qualitative and quantitative results being a DNA yield from hard dental tissues approximately 30% of those extracted from the whole tooth. Our results indicate salting out as a preferable method due to its rapidity and usefulness.

[Correlation between serum glutathione reductases and bone densitometry values]. / Correlazione tra glutatione-reduttasi serica e valori densitometrici ossei.

Free radicals, because of their marked chemical activity, have often been found to be involved in many human diseases. Enzymatic antioxidant systems, namely glutathione-reductase, present both in red blood cells and in serum, have been demonstrated to play a key role as free radicals scavengers. The present work has been carried out in order to evaluate the possible role played by free radicals in the demineralization process of the bone matrix. Glutathione-reductase activity, assayed by a slightly modified Horn's method, was related to bone density measurements. All the subjects with reduced densitometric values showed reduced glutathione-reductase levels. Our results seem to support the hypothesis of a strict relationship between low activity of antioxidant systems and demineralization process of the bone, in consequence of enhanced free radical levels.