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Biomedical subjects

L Fonzi

Publications and source records attributed to L Fonzi.

At least 19 recordsLinked to original sources
PubMed1991

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

The major goal of endodontic therapy has been achieved by condensing filling materials into the root canal. It is not uncommon to find excess material in the periapical tissue. It therefore becomes obligatory to use filling materials that have acceptable biocompatibility. The purpose of this investigation was to obtain a "toxicity profile" of some root canal materials and to compare our observations to study results found in literature. 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 then implanted subcutaneously into rats. The implants were left in situ for periods of 30 and 90 days. The hemolysis test was used for in vitro evaluations. The histological examination showed cellular responses of different intensity and extent. In some cases severe infiltration of inflammatory cells and areas with necrostis were observed. As a result, the root canal materials evaluated showed slight, moderate, and severe reactions, therefore, a different pattern in tissue response.

Animals↗
PubMed1989

Behaviour of adenylic and pyridinic compounds in gingival tissue after a short-term exposure to air.

Biochemical variations of adenine and pyridine compounds in human gingival grafts during the period between excision and implantation have been studied. These groups of compounds are considered as "indicators" of the metabolic and energetic status of the living cells. Adenylic compounds such as ATP, ADP and AMP are involved in numerous metabolic processes as "modulators" of allosteric enzymes. NAD+ and NADP+ are involved in the carbohydrate metabolism as co-factors of many reactions of oxydoreduction. The exposure to air of the gingival tissue induces modifications in the energy state of the cells as well as in the ox-reox system. No variation is detectable in the intermediates of the pyridine compounds cycle.

Adenine Nucleotides↗
PubMed1988

Non specific acid esterase activity in human periapical inflammatory cells.

The fine structural localization of non specific acid alpha-naphthyl acetate esterase activity (ANAE) in human periapical inflammatory cells was studied in sections of paraffin embedded tissue of 20 human periapical lesions (granulomas). Examination of specimens incubated with ANAE resulted in ANAE+ cells interpreted as T-lymphocytes, monocytes, macrophages, giant cells and plasma cells. ANAE- lymphocytes were interpreted as B cells. Our findings do not seem to confirm the presence among human periapical inflammatory cells of NK (natural killer) cells. T-lymphocytes were the most represented cellular type. The macrophages with ANAE+ reaction were numerous in all specimens observed and the variation in staining intensity could reflect a varying stage of activation. These findings allow conclusions about the role of T-lymphocyte mediated immune reaction in the pathogenesis of periapical lesions. The possibility that the activated T-lymphocytes within the periapical lesions may have a critical role in establishing and maintaining granuloma formation is also discussed.

Carboxylesterase↗
PubMed1986

Effect of the novel synthetic protease inhibitor furoyl saccharin on elastase-induced emphysema in rabbits and hamsters.

Furoyl saccharin, a novel heterocyclic acylating agent which has been previously found to possess a potent inhibitory capacity in vitro for elastase and other serine proteases, has been investigated in vivo in two acute animal models of emphysema. In hamsters, intratracheal (i.tr.) administration of 0.1 mg porcine pancreatic elastase resulted seven days later, in a 42% increase of the mean linear intercept (Lm). Addition of 0.3 mg to 0.3 mg furoyl saccharin to elastase exhibited a partial, not dose-related, but statistically significant inhibition of the increase of LM. Addition of 1 mg furoyl saccharin (equivalent to a dose of 12.5 mg/kg) completely abolished the increase in Lm. In the rabbit i.tr. instillation of 3.7 mg porcine pancreatic elastase induced within seven days, a 48% increase of the Lm, a 27% decrease of the internal surface area (ISA) of the lungs and a 33% decrease of the ISA corrected to an arbitrary total lung volume of 70 ml (ISA70). Furoyl saccharin given i.tr. 15 min prior to elastase at the doses 3, 10 and 20 mg prevented significantly in a dose-related manner, the changes in Lm, ISA and ISA70. The highest furoyl saccharin dose (equivalent to a dose of 10.8 mg/kg) completely protected against the emphysematous lesion. Additionally furoyl saccharin (20 mg i.tr.) prevented in the rabbit model the depletion in lung insoluble elastin and the increase in salt soluble collagen induced by the elastase administration. These results show that furoyl saccharin also in vivo has a marked antielastase activity.

Animals↗
PubMed1984

Pulmonary changes induced in rabbits by long-term exposure to n-hexane.

New Zealand male rabbits were exposed in an inhalation chamber to 3,000 ppm of n-hexane 8 h/day, 5 days/week for 24 weeks, resulting in a total of 120 exposures. After a further 120 days in clean air, morphologic examination of lungs by light and transmission electron microscopy (TEM) revealed three important exposure-related lesions. These consisted of air space enlargement centered on respiratory bronchioles and alveolar ducts (centriacinar emphysema), scattered foci of pulmonary fibrosis, and papillary tumors of non-ciliated bronchiolar epithelial cells. At TEM examination these tumors were rather homogeneous and were found to consist of cells showing both small and large electron dense ovoid granules in their cytoplasmic matrix, a feature that has been described for Clara cells. The implications of these findings are discussed.

Animals↗
PubMed1984

[Root caries].

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Aged↗
PubMed1982

Ultrastructural observations on morphogenesis of atypical cilia.

Though ultrastructural studies of bronchial epithelium both in man and in experimental animals revealed in a variety of conditions the presence of pathologically altered cilia, little is known about their genesis and significance. In this work we have described the alterations noticed in ciliary morphology during the formation of atypical cilia. A probable mechanism for their production is also proposed on the basis of our results.

Animals↗
PubMed1979

[Pulmonary damage in the rabbit caused by porcine pancreatic elastase and leukocyte lysate: unusual microscopic aspects].

Intratracheal injection of rabbit whole leukocyte homogenate induced emphysema-like lesions in rabbits. The lesions were produced only by preparations having elastinolytic activity. The pathological aspects appeared similar to those induced by the administration of porcine pancreatic elastase. The pulmonary changes, resembling several of the anatomic appearances of panacinar human emphysema, may be a suitable experimental model for studying histogenesis of panacinar human emphysema. Numerous abnormal fenestrations were present in air spaces walls and were a constant feature in opposition to that has been reported in elastase-treated hamsters. For the presence of a prominent dilatation of the periarterial lymphatic network, this experimental model might be used also for studying the ultrastructural features of pulmonary lymphatic vessels.

Animals↗