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L Fonzi

Publications and source records attributed to L Fonzi.

46 records · Page 3Linked to original sources
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[Enamel pearls: the ultrastructural aspects and morphogenesis hypotheses].

Five enamel pearls were examined by scanning electron microscope. Some external pearls presented a bare enamel surface, others were covered by a thin layer of cementum. The enamel pearls showed irregular dystrophic enamel surface or a thin layer without structure, rows of irregular Tome's processes pits, enamel caps and focal holes. Some enamel pearls revealed little areas of enamel surface resorption like-resorbing lacunae with, in some cases, areas of tissue repair.

Dental Enamel↗
PubMedDate not supplied

[In vivo and in vitro biocompatibility tests of endodontic cements].

The major goal endodontic therapy has been achieved by condensing filling materials into the root canal. It's not uncommon to find excess material into the periapical tissue. It therefore becomes obligatory to use fillings materials that have acceptable biocompatibility. The purpose of this investigation was to obtain a "toxicity profile" of some endodontics materials and to compare our observations to results present in literature. The gutta-percha and five endodontic filling cements were tested "in vivo" and "in vitro". The in vivo biocompatibility involved the placement of the test material in 10 mm. Teflon tubes with an outer diameter of 1.3 mm which were implanted subcutaneously into rats. The implants were left in situ for periods of 30 and 90 days. The "hemolysis test" is designed for "in vitro" evaluations. The histological examination showed different intensity and extent cellular responses. In some cases severe infiltration of inflammatory cell and areas with necrotic were seen. At conclusion, the endodontics material evaluated showed slight, moderate and severe reactions; therefore a different pattern in tissue response.

Animals↗
PubMedDate not supplied

In vitro and in vivo effects of chloramine T on rat serum elastase inhibitor.

Recent studies have shown that oxidizing agents may block the elastase inhibitory activity of alpha 1-antiproteinase in humans and some animal species. It has been postulated that this protein plays a critical role in modulating the activity of the neutral proteinase, i.e. elastase, in the lung; its inactivation has been implicated in the destruction of lung tissue seen in emphysema. In this work, we have studied the inactivation in vitro of rat serum elastase inhibitor by chloramine T (CT) and whether the in vivo use of the same oxidizing agent in the development of a functional model of alpha 1-antiproteinase deficiency in the rat is feasible. Although serum alpha 1-antiproteinase is readily inactivated in vitro by CT, it was observed, in vivo, that serum elastase inhibitory capacity was reduced to about 28-35% of initial levels 1-3 h after CT injection, and returned to control values within 9 h. Therefore, the in vivo study demonstrated that in the rat a functional model of alpha 1-antiproteinase deficiency cannot be achieved by inactivation of the protein molecule with CT. The relatively short half-life (1.45 h) of the serum elastase inhibitor found in normal rats is consistent with a rapid synthesis of the protein molecule, which might contribute to the fast recovery of the elastase inhibitory capacity observed in experimental animals after CT administration.

Animals↗
PubMedDate not supplied

Ultrastructural aspects of two different mast cell populations in human healthy gingival tissue.

The results of our recent microscopy studies clearly have demonstrated the constant presence of numerous metachromatic cells in healthy human gingival connective tissue. Despite the great number of studies on mast cell population in many human organs (lung, skin, uterus, and bowel), at the present time few are the studies regarding the morphostructural aspects of mast cells in the human gingiva. The aim of this study was to assess by transmission electron microscopy the presence of mast cells in the healthy human gingiva and to characterize the ultrastructural aspects of mast cells populations. 30 specimens of human gingival tissue were collected from 30 patients with informed consent. The samples were prepared for T.E.M. examination. In all the ultrathin sections observed we detected numerous and ubiquitarious mast cells. These exhibited several morphological types of cytoplasmic granules with characteristic subgranular architectural variety in shape and density. This allowed us to divide mast cells into two groups: cells with granules consisted of compact coiled scrolls, fine granular material and lattice--grafting configuration, and cells containing granules with discrete scrolls formed by more concentric lamellae and particulate structure. The two ultrastructural aspects observed correspond to McTC and McT of the international literature. Therefore in the human gingival connective tissue, like in other organs, two types of mast cells are clearly present. Surprisingly, the human gingival tissue shows, like the lung, McT as the prevailing subpopulation, in contrast to the skin, uterus and gastrointestinal submucosa where McTC prevail.

Adolescent↗