RESUMO
BACKGROUND: Different enhanced peroxide formulations have been developed to overcome mineral loss during tooth whitening. This study investigated the impact on tooth whitening from combining a CPP-ACP paste with home peroxide agents at several proportions. METHODS: Ninety bovine incisors were randomly allocated into nine groups (n = 10) and exposed to 7.5% hydrogen peroxide (HP), 16% carbamide peroxide (CP), a CPP-ACP paste (Tooth Mousse/MI Paste, GC Corporation, Tokyo, Japan) and blends of HP/CP:MI at three proportions (1:1, 2:1 and 1:2). Tooth whitening was performed for 14 days and its effectiveness was measured by a spectrophotometer utilizing the CIE L*a*b* system (ΔE, ΔL*, Δa* and Δb*). Colour readings were measured at baseline (T0), 7 days of bleaching (T7), 14 days of bleaching (T14) and 7 days after the end of bleaching (T21). Data were analysed by two-way ANOVA for paired averages followed by the Tukey's test and Pearson's correlation at 5%. RESULTS: Although CP produced the greatest colour change (ΔE), all whitening protocols were considered to be effective regardless of the CPP-ACP presence. In general, greater changes in ΔE, ΔL*, Δa* and Δb* were detected at T14, with T21 exhibiting similar results to those at T7. A greater number of strong correlations with ΔE values was found for a* (11/15). CONCLUSIONS: Within the limitations of this study, the results indicate that the CPP-ACP paste did not affect tooth whitening efficacy.
Assuntos
Caseínas/farmacologia , Clareadores Dentários/administração & dosagem , Clareamento Dental/métodos , Animais , Peróxido de Carbamida , Bovinos , Colorimetria , Dentina/efeitos dos fármacos , Antagonismo de Drogas , Combinação de Medicamentos , Peróxido de Hidrogênio/administração & dosagem , Peróxidos/administração & dosagem , Espectrofotometria , Ureia/administração & dosagem , Ureia/análogos & derivadosRESUMO
Epithelial cells are important components of the thymus microenvironment and are involved in thymocyte differentiation. The production and secretion of sulfated glycosaminoglycans by these cells grown in culture were investigated using labeling with radioactive 35S-Na2SO4 and 3H-glucosamine. The major glycosaminoglycans synthesized by these cells are heparan sulfate and hyaluronic acid. The structure of the heparan sulfate was investigated by the pattern of degradation products formed by deaminative cleavage with nitrous acid. The ratio 35S-sulfate/ H-glucosamine is high in the segments of the heparan sulfate released during the deaminative cleavage with nitrous acid but low in the resistant portion of the molecule. Thus, the heparan sulfate synthesized by the thymic epithelial cells contains a highly sulfated region. Digestion with heparitinase reveals that this highly sulfated region is a heparin-like segment of the molecule. The heparan sulfate is rapidly incorporated into the cell surface but its secretion to the extracellular medium requires a longer incubation period. Finally, heparin was used to mimic the possible effect of this heparan sulfate with a highly sulfated region, as ascertained by its ability to modulate thymocyte adhesion to thymic epithelial cells. Since heparin actually enhanced thymocyte adhesion, it is suggested that the heparan sulfate described herein, secreted by the thymic epithelium, may play a role upon intrathymic heterotypic cellular interactions.
Assuntos
Células Epiteliais/metabolismo , Heparitina Sulfato/biossíntese , Heparitina Sulfato/metabolismo , Enxofre/metabolismo , Timo/citologia , Animais , Fracionamento Celular , Linhagem Celular , Sulfatos de Condroitina/biossíntese , Sulfatos de Condroitina/metabolismo , Ensaios Enzimáticos Clínicos , Dissacarídeos/metabolismo , Células Epiteliais/citologia , Feminino , Glicosaminoglicanos/metabolismo , Ácido Hialurônico/biossíntese , Ácido Hialurônico/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Oligossacarídeos/metabolismo , Polissacarídeo-Liases/farmacologia , Radioisótopos de Enxofre , Fatores de Tempo , TrítioRESUMO
American visceral leishmaniasis is a main public health matter in Brazil. Since dogs have been incriminated as the main urban reservoir of AVL agent Leishmania chagasi, a cohort study aimed at understanding the dynamics of the canine infection was carried out in Jequié--an endemic community in the Northeast of Brazil. The inhabited urban and periurban areas of Jequié were divided into 140 clusters of 0.25 km2. All 1681 dogs domiciled in 34 randomly selected clusters were screened for Leishmania antibodies in an enzyme-linked immunosorbent assay. After the seropositive dogs were painlessly eliminated, a cohort of 1286 seronegative dogs was followed up for 18 months, yielding a total of 1739.7 dog-years. The overall incidence of Leishmania infection, as assessed by the detection of Leishmania antibodies in blood samples collected every six months, was 6.55 cases/100 dog-years (95% confidence interval; CI 6.04-7.26). Two subsets of clusters, with 0.70 and 1.35 relative risks of infection, were identified. The annual emigration rate was 2.26 cases/100 dog-years (95% CI 1.86-2.66). The implications of these findings for the control of American visceral leishmaniasis are discussed.
Assuntos
Doenças do Cão/epidemiologia , Leishmaniose/veterinária , Animais , Anticorpos Antiprotozoários/sangue , Brasil/epidemiologia , Reservatórios de Doenças , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Cães , Ensaio de Imunoadsorção Enzimática , Feminino , Incidência , Leishmaniose/epidemiologia , Leishmaniose/imunologia , Leishmaniose/parasitologia , MasculinoRESUMO
Jequie, a community of about 144,500 inhabitants located in the State of Bahia, Brazil, is endemic for both visceral and cutaneous leishmaniases. In the present epidemiologic study, the urban and inhabited periurban areas of the town were divided into 140 clusters of 0.25 km2 each. The seroprevalence of canine Leishmania antibodies was investigated using an enzyme-linked immunosorbent assay as a screening test since its sensitivity was significantly higher than that of an indirect immunofluorescence assay. A total of 1,681 dogs was surveyed in 34 randomly sampled clusters. The overall prevalence of Leishmania antibodies in the dog population was 23.5%, with intracluster prevalences ranging from 0% to 67%. There was no correlation of these seroprevalences with the intracluster densities of canine populations, or with the distances from individual clusters to the town center. Moreover, the Leishmania transmission did not seem to follow any clear-cut spatial pattern, since large disparities in the seroprevalences of contiguous clusters were found. Curiously, human cases of visceral leishmaniasis have never been observed in some clusters with a relatively high prevalence of canine seroprevalences. Eight parasite isolates from seropositive dogs were found to belong to the same serodeme and zymodeme as Leishmania (L.) chagasi. The implications of these findings with respect to the epidemiology and control of American visceral leishmaniasis are discussed.