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Biomedical subjects

R Di Giorgio

Publications and source records attributed to R Di Giorgio.

7 recordsLinked to original sources
PubMed2000

Age-related modifications in human unstimulated whole saliva: a biochemical study.

Human whole saliva contains a number of antimicrobial agents, and lysozyme, lactoferrin, secretory IgA and peroxidase are among the best known. Peroxidase catalyzes a reaction involved in the inhibition of bacterial growth and metabolism, and the prevention of hydrogen peroxide accumulation, thus protecting proteins from the action of oxygen and reactive oxygen species (ROS). To better understand the role played by the oxidative stress in the aging process, we studied the relationship between total protein content, peroxidase activity, malondialdehyde (MDA) and nitric oxide (NO) content of human unstimulated whole saliva in 169 healthy subjects subdivided into groups according to age. Our results show a significant decrease in peroxidase activity with age. Moreover, the increase in saliva lipid peroxide levels indicates an enhanced free radical production that may contribute to tissue damage. On the other hand, findings concerning human unstimulated whole saliva NO content showed a significant increase in elderly subjects, suggesting that an enhanced NO production might depend on a stimulation of leukocyte-inducible NO synthase (i-NOS) activity. Our results suggest that during aging the oral tissues may become more susceptible to environmental factors due to a modification in the balance between different antimicrobial agents.

Adolescent↗
PubMed1999

[Dentinogenesis imperfecta. Scanning electron microscopic study and microanalysis].

BACKGROUND: Dentinogenesis imperfecta (DI) is an inherited dentine defect which affects both the primary and secondary dentitions. Shields et al. in 1973 suggested a classification of DI within three types: type I, associated with osteogenesis imperfecta (OI), type II and type III. Although the varying clinical, radiographic and histological findings in DI have been described in detail, an available method for closer examination of the abnormal dentine matrix, electron microscopy, has seldom been used. Scanning and transmission electron microscopy studies can help to understand the pathogenesis of the different types of heritable dentine defects and the diagnosis and classification of these diseases. The aim of the present study was to evaluate a case of DI using scanning electron microscopy and microanalysis. METHODS: Dentine was obtained from tooth samples from a fourteen-year-old boy affected by DI and from third molars extracted for therapeutic reasons used as controls. Samples were observed with a scanning electron microscope, scanning electron micrographs were evaluated with an image analysis program and specimens were finally observed with a scanning electron microscope equipped for micro-analysis. RESULTS AND CONCLUSIONS: The results obtained showed that the total number of dentinal tubules was significantly reduced and the presence of a dentine mineralization defect in the patient affected by DI, in comparison to the controls.

Adolescent↗
PubMed1999

Changes in the composition of human unstimulated whole saliva with age.

The aim of this study was to evaluate changes in the concentration of certain components of human unstimulated whole saliva during aging, in order to better understand the role played by aging in oral health. In particular, we studied total protein concentration, alpha-amylase activity, sialic acid content and calcium and phosphorus concentrations in 100 healthy subjects of both genders, aged between 10 and 80 years, who were subdivided into four groups according to their age: 10-25 years, 26-40 years, 41-65 years, and 66-80 years. Other than sialic acid, the concentrations of the components studied were not affected by age. There was a significant negative correlation between sialic acid content and age. Our data indicate the presence of a decreased submandibular/sublingual function with aging, thus suggesting the possibility of a concomitant reduction in the modulating action of unstimulated whole saliva on the oral flora.

Adolescent↗
PubMed1998

Biochemical modifications of human whole saliva induced by pregnancy.

OBJECTIVE: To assess human unstimulated whole saliva components during pregnancy, to determine the relation, if any, between pregnancy and oral health, particularly total protein concentration, alpha-amylase activity, sialic acid content and calcium and phosphate concentrations were evaluated. DESIGN: Cross-sectional study. PARTICIPANTS: Forty-five healthy primigravid women; 15 nonpregnant women acted as controls. RESULTS: 1. A higher total protein content at 10 and 21 weeks of gestation with respect to the controls and to pregnant women at 40 weeks; 2. a higher alpha-amylase activity at 10 and 21 weeks of gestation compared with the controls and to pregnant women at 40 weeks; 3. an increased sialic acid content at 21 and 40 weeks; 4. decreased calcium and phosphorus concentrations at 21 and 40 weeks of gestation. CONCLUSIONS: Pregnancy modifies saliva composition. This could play a pivotal role in the incidence of pregnancy-induced dental caries.

Adult↗