Search

Our objective was to determine if protons allow for the expansion of treatment volumes to cover high-risk nodes in patients with regionally advanced non-small-cell lung cancer. In this study, 5 consecutive patients underwent external-beam radiotherapy treatment planning. Four treatment plans were generated for each patient: 1) photons (x-rays) to treat positron emission tomography (PET)-positive gross disease only to 74 Gy (XG); 2) photons (x-rays) to treat high-risk nodes to 44 Gy and PET-positive gross disease to 74 Gy (XNG); 3) protons to treat PET-positive gross disease only to 74 cobalt gray equivalent (PG); and 4) protons to treat high-risk nodes to 44 CGE and PET-positive gross disease to 74 CGE (PNG). We defined high-risk nodes as mediastinal, hilar, and supraclavicular lymph nodal stations anatomically adjacent to the foci of PET-positive gross disease. Four-dimensional computed tomography was utilized for all patients to account for tumor motion. Standard normal-tissue constraints were utilized. Our results showed that proton plans for all patients were isoeffective with the corresponding photon (x-ray) plans in that they achieved the desired target doses while respecting normal-tissue constraints. In spite of the larger volumes covered, median volume of normal lung receiving 10 CGE or greater (V10Gy/CGE), median V20Gy/CGE, and mean lung dose were lower in the proton plans (PNG) targeting gross disease and nodes when compared with the photon (x-ray) plans (XG) treating gross disease alone. In conclusion, proton plans demonstrated the potential to safely include high-risk nodes without increasing the volume of normal lung irradiated when compared to photon (x-ray) plans, which only targeted gross disease.

Because dentin is more caries-susceptible than enamel, its demineralization may be more influenced by additional fluoride (F). We hypothesized that a combination of professional F, applied as acidulated phosphate F (APF), and use of 1100-ppm-F dentifrice would provide additional protection for dentin compared with 1100-ppm-F alone. Twelve adult volunteers wore palatal appliances containing root dentin slabs, which were subjected, during 4 experimental phases of 7 days each, to biofilm accumulation and sucrose exposure 8x/day. The volunteers were randomly assigned to the following treatments: placebo dentifrice (PD), 1100-ppm-F dentifrice (FD), APF + PD, and APF+FD. APF gel (1.23% F) was applied to the slabs once at the beginning of the experimental phase, and the dentifrices were used 3x/day. APF and FD increased F concentration in biofilm fluid and reduced root dentin demineralization, presenting an additive effect. Analysis of the data suggests that the combination of APF gel application and daily regular use of 1100-ppm-F dentifrice may provide additional protection against root caries compared with the dentifrice alone.

The anticaries effect of professional fluoride (F) application has been attributed to calcium-fluoride-like deposits (CaF(2)) formed on enamel, but this has not been clearly demonstrated. We hypothesized that CaF(2) formed on plaque-free enamel by F application would reduce enamel demineralization due to the increase of F availability in fluid of subsequently formed plaque. We created distinct levels of CaF(2) on enamel to evaluate a dose-response effect. Enamel blocks were mounted in contact with a S. mutans test plaque and used in situ by 10 volunteers. F released to the fluid phase of this substrate ("plaque fluid") was measured before a cariogenic challenge. "Plaque fluid" F concentration was highly correlated to the enamel CaF(2) concentration (r = 0.96, p < 0.001) and to consequent enamel demineralization (r = -0.75, p < 0.001). The results suggest that F released to plaque fluid from CaF(2) formed on enamel may play a significant role in the anticaries effect of professionally applied F agents.

Dental caries is a biofilm-dependent oral disease, and fermentable dietary carbohydrates are the key environmental factors involved in its initiation and development. However, among the carbohydrates, sucrose is considered the most cariogenic, because, in addition to being fermented by oral bacteria, it is a substrate for the synthesis of extracellular (EPS) and intracellular (IPS) polysaccharides. Therefore, while the low pH environment triggers the shift of the resident plaque microflora to a more cariogenic one, EPS promote changes in the composition of the biofilms' matrix. Furthermore, it has recently been shown that the biofilm formed in the presence of sucrose presents low concentrations of Ca, P(i), and F, which are critical ions involved in de- and remineralization of enamel and dentin in the oral environment. Thus, the aim of this review is to explore the broad role of sucrose in the cariogenicity of biofilms, and to present a new insight into its influence on the pathogenesis of dental caries.

Calcium (Ca), inorganic phosphorus (P(i)), and fluoride (F) concentrations are low in the whole plaque biofilm formed under exposure to sucrose. It was hypothesized that this would be reflected in the biofilm fluid, where these low values should greatly influence the de/remineralization process. Dental biofilms were formed in situ over enamel blocks mounted in palatal appliances and exposed 8 times/day to distilled water, glucose+fructose, or sucrose solutions for 14 days. While Ca, P(i), and F concentrations in the whole biofilms were significantly lower in the glucose+fructose and sucrose groups, no effect on biofilm fluid was observed, even after a cariogenic challenge. An increase in whole biofilm mineral ions was observed 24 hrs after the carbohydrate treatments were suspended, but this effect was also not observed in the fluid. These results suggest that there is a homeostatic mechanism that maintains biofilm fluid mineral ion concentration, regardless of its total concentration in the whole biofilm.

The acquired dental pellicle helps prevent erosion, but the protection level is unknown. This in situ study tested whether a two-hour pellicle protects against different erosive challenges by orange juice. Subjects wore palatal appliances loaded with either enamel or dentin specimens. Pellicle was allowed to form, or not (control), on the surfaces of the specimens intra-orally for 2 hrs before the erosive challenges of 0 (control), 10, 20, and 30 minutes' duration. Specimens were randomly removed from the appliances after each challenge. Percentage of surface microhardness change (%SMC) was determined for the enamel specimens, and that of mineral loss and lesion depth for the dentin specimens. Enamel specimens with the pellicle showed a significantly lower %SMC, only after the 10-minute challenge. No protection was found for dentin. It was concluded that the acquired pellicle reduced dental erosion, but that this effect was limited to the less severe erosive challenge on enamel surfaces.

A low-fluoride (F) dentifrice has been recommended to reduce the risk of dental fluorosis, but its anti-caries efficacy is questionable compared with that of conventional dentrifices (1000-1100 microg F/g). The tested hypothesis was that conventional dentifrices might be safe if used soon after meals, since food interferes with F absorption. In a crossover, double-blind study, 11 volunteers ingested a dentifrice slurry containing 0 (placebo), 550 (low F), or 1100 microg F/g in 3 gastric content situations: on fasting, or 15 min after breakfast or lunch. F was analyzed in saliva and 24-hour urine samples. The conventional dentifrice ingested after lunch resulted in only 10% higher F absorption than the low-F ingested on fasting. Analysis of the data suggests that the risk of fluorosis could be reduced by the use of either a low-F dentifrice or a conventional dentifrice, if toothbrushing occurred soon after meals.

Apigenin (Api) and tt-farnesol (Far) are two naturally occurring agents that affect the development of cariogenic biofilms. Fluoride (F) interferes physicochemically with caries development and also exhibits antibacterial activity. We examined whether the association of Api and Far enhance the anti-caries properties of F by acting cooperatively on the expression of virulence of Streptococcus mutans. The biological effects of each of the agents were greatly enhanced when used in combination with F. In general, biofilms treated with Api and/or Far in combination with F displayed less biomass and fewer insoluble glucans and iodophilic polysaccharides than did those treated with the test agents alone (P < 0.05). The combination of the test agents with F was highly effective in preventing caries development in rats, especially Api+Far+F, and results were comparable with those observed with chlorhexidine + F (positive control). Results from these studies showed that apigenin and tt-farnesol may enhance the cariostatic effectiveness of fluoride.

Since the effect of the combination of methods of fluoride use on enamel demineralization and on plaque composition is not clearly established, this study examined the effect of the combination of acidulated phosphate fluoride (APF) application and F dentifrice on enamel demineralization and on plaque composition. In this crossover study, 16 volunteers, wearing a palatal appliance containing bovine enamel blocks, were subjected to 4 treatment groups: non-fluoridated dentifrice (PD), FD, APF+PD, and APF+FD. The APF was applied to the enamel before the 14-day experimental period. During the experimental period, test dentifrices were applied 3x/day, and a 20% sucrose solution was applied 4x and 8x/day by being dripped on the blocks. Although APF application was able either to increase F concentration in plaque or to reduce the % of mutans streptococci, its combination with F dentifrice use neither reduced enamel mineral loss nor changed any other measured plaque variable with respect to the FD group alone.

Ionomeric materials release different proportions of fluoride and aluminum. Their simultaneous effect on the acidogenicity and composition of S. mutans biofilm is unknown. Six cylindrical specimens of each material (Ketac-fil, Vitremer, Fuji-Ortho LC, F-2000, and Z-100) were incubated with S. mutans GS-5 in culture media containing 5% sucrose (w/v). The media were changed daily for seven days, during which the pH and concentrations of fluoride and aluminum were determined. Furthermore, the concentrations of these ions and insoluble polysaccharide were determined in the biofilm formed at the end of the experimental period. The results showed that all the materials tested released fluoride. However, Vitremer released the highest amount of aluminum and was the most effective in reducing the acidogenicity of S. mutans biofilms. It also significantly affected both biofilm formation and composition. Thus, this study suggests that aluminum released by ionomeric materials may enhance the biological effects of fluoride.

Objective: To determine whether the number of emergency department (ED) visits for acute asthma exacerbations could be decreased by providing patients with a comprehensive program of asthma management delivered by a pharmacist and a physician., Design: Patients were selected from the ED and asked to attend a special asthma clinic that provided education about asthma and proper use of asthma medications, regular telephone contact between the pharmacist and patient, and an open-door clinic policy., Setting: A university-affiliated urban teaching hospital., Participants: The study population consisted of 25 asthmatic patients who were at least 18 years of age and who were seen in the ED a minimum of 3 times in a 12-month period., Main Outcome Measures: The number of visits to the ED for acute exacerbations of asthma was measured. Patients served as their own controls. The number of ED visits for asthma during the 6-month study period was compared with two 6-month periods prior to the study period for each patient., Results: The total number of ED visits for the 25 enrolled patients six months prior to their enrollment into the study was 92; the number of ED visits during the same months of the study in the prior year was 47. During the study period, there were only 6 ED visits for asthma exacerbations., Conclusions: The comprehensive asthma management program reduced the number of ED visits for acute exacerbations of asthma.

Objective: To report unusually high theophylline dosing requirements in a smoker receiving concomitant therapy with phenytoin and phenobarbital., Design: Single case report., Setting: 517-bed, university teaching hospital., Patient: 29-year-old woman with newly diagnosed asthma, heavy smoking history, and a seizure disorder., Results: The additive influence of smoking, phenytoin, and phenobarbital greatly increased the theophylline dosing requirements. Doses of up to 4 g/d (59 mg/kg/d) were required to achieve adequate symptomatic relief of her asthma as well as to provide therapeutic serum theophylline concentrations., Conclusions: Multiple polymorphisms may additively influence theophylline metabolism and exceptionally large theophylline doses may be required in some patients who smoke and are comedicated with phenytoin and phenobarbital.