Reduced CD8+ T cells infiltration can be associated to a malignant transformation in potentially malignant oral epithelial lesions

Clinical Oral Investigations - The aim of this study was to evaluate the immunohistochemical expressions of PD1, CD4+, and CD8+ in premalignant lesions (OPML) that were transformed into oral...     

Chemical dispersants can suppress the activity of natural oil-degrading microorganisms

During the Deepwater Horizon oil well blowout in the Gulf of Mexico, the application of 7 million liters of chemical dispersants aimed to stimulate microbial crude oil degradation by increasing the bioavailability of oil compounds. However, the effects of dispersants on oil biodegradation rates are debated. In laboratory experiments, we simulated environmental conditions comparable to the hydrocarbon-rich, 1,100 m deep plume that formed during the Deepwater Horizon discharge. The presence of dispersant significantly altered the microbial community composition through selection for potential dispersant-degrading Colwellia, which also bloomed in situ in Gulf deep waters during the discharge. In contrast, oil addition to deepwater samples in the absence of dispersant stimulated growth of natural hydrocarbon-degrading Marinobacter. In these deepwater microcosm experiments, dispersants did not enhance heterotrophic microbial activity or hydrocarbon oxidation rates. An experiment with surface seawater from an anthropogenically derived oil slick corroborated the deepwater microcosm results as inhibition of hydrocarbon turnover was observed in the presence of dispersants, suggesting that the microcosm findings are broadly applicable across marine habitats. Extrapolating this comprehensive dataset to real world scenarios questions whether dispersants stimulate microbial oil degradation in deep ocean waters and instead highlights that dispersants can exert a negative effect on microbial hydrocarbon degradation rates.Crude oil enters marine environments through geophysical processes at natural hydrocarbon seeps (1) at a global rate of ∼700 million liters per year (2). In areas of natural hydrocarbon seepage, such as the Gulf of Mexico (hereafter, the Gulf), exposure of indigenous microbial communities to oil and gas fluxes can select for microbial populations that use petroleum-derived hydrocarbons as carbon and energy sources (3, 4). The uncontrolled deep-water oil well blowout that followed the explosion and sinking of the Deepwater Horizon (DWH) drilling rig in 2010 released about 750 million liters of oil into the Gulf. Seven million liters of chemical dispersants were applied (5) with the goal of dispersing hydrocarbons and stimulating oil biodegradation. A deep-water (1,000–1,300 m) plume, enriched in hydrocarbons (6–11) and dioctyl sodium sulfosuccinate (DOSS) (12, 13), a major component of chemical dispersants (14), formed early in the discharge (7). The chemistry of the hydrocarbon plume significantly altered the microbial community (11, 15–17), driving rapid enrichment of low-abundance bacterial taxa such as Oceanospirillum, Cycloclasticus, and Colwellia (18). The natural hydrocarbon degraders in Gulf waters were either in low abundance or absent in DWH deep-water plume samples (18).Chemical dispersants emulsify surface oil slicks, reduce oil delivery to shorelines (19), and increase dissolved oil concentrations, which should make oil more bioavailable (20) and stimulate biodegradation (21). The efficacy of dispersants in stimulating oil biodegradation is debated (22) and negative environmental effects have been documented (23). Dispersant application often requires ecological tradeoffs (24). Surprisingly little is known about the impacts of dispersants on the activity and abundance of hydrocarbon-degrading microorganisms (25). This work addressed three key questions: (i) Do dispersants influence microbial community composition? (ii) Is the indigenous microbial community as effective at oil biodegradation as microbial populations following dispersant/dispersed oil exposure? (iii) Does chemically dispersed oil stimulate hydrocarbon biodegradation rates?Laboratory experiments were used to unravel the effects of oil-only (supplied as a water-accommodated fraction, “WAF”), Corexit 9500 (“dispersant-only”), oil–Corexit 9500 mixture (chemically enhanced water-accommodated fraction, CEWAF) or a CEWAF with nutrients (CEWAF + nutrients) (SI Appendix) on Gulf deep-water microbial populations (SI Appendix, SI Text and Figs. S1 and S2). Experimental conditions (SI Appendix, Table S1) mimicked those prevailing in the DWH deep-water hydrocarbon plume (6–13, 18), the chemistry of which varied substantially over space and time (18). Amending samples with WAFs and CEWAFs assured that observed differences in microbial community composition and activity would be driven by compositional differences (e.g., the presence or absence of dispersants) in the dissolved organic carbon (DOC) pool rather than by differences in the bulk DOC concentration (26, 27). We developed an improved radiotracer method to directly quantify hydrocarbon oxidation rates. The microbial community composition was monitored over time using 16S rRNA amplicon sequencing. Dispersant application selected for specific microbial taxa and oligotypes with 16S rRNA gene sequences similar to those recovered in situ during the DWH discharge. Surprisingly, CEWAF (± nutrients) addition did not enhance microbial activity or microbial oil-degradation rates.     

Progression of periodontitis in a sample of regular and irregular compliers under maintenance therapy: a 3-year follow-up study

Background: To our knowledge, prospective studies (matched for sex, smoking, and diabetes) that investigated the influence of compliance in the progression of periodontitis and tooth loss in periodontal maintenance therapy (PMT) programs were not previously reported. Methods: A total of 58 regular complier (RC) and 58 erratic complier (EC) individuals were recruited from a prospective cohort with 238 patients under PMT and matched by sex, diabetes, and smoking habits. A full‐mouth periodontal examination that included bleeding on probing (BOP), probing depths (PDs), clinical attachment levels, and number of teeth were determined at all PMT visits during a 3‐year interval. The influence of variables of interest was tested through multivariate logistic regression. Results: The progression of periodontitis and tooth loss was significantly lower among RC compared to EC patients. A higher progression of periodontitis was observed among EC patients who smoked. The final logistic model for the progression of periodontitis in the RC group included smoking (odds ratio [OR]: 4.2) and >30% of sites with BOP (OR: 2.8), and the final logistic model for the progression of periodontitis in the EC group included smoking (OR: 7.3), >30% of sites with BOP (OR: 3.2), PDs of 4 to 6 mm in 10% of sites (OR: 3.5), diabetes (OR: 1.9), and number of lost teeth (OR: 3.1). Conclusions: RC patients presented a lower progression of periodontitis and tooth loss compared to EC patients. This result highlighted the influence of the pattern of compliance in maintaining a good periodontal status. Moreover, important risk variables such as smoking and diabetes influenced the periodontal status and should be considered when determining the risk profile and interval time for PMT visits.     

Association between maternal periodontitis and an increased risk of preeclampsia

BACKGROUND: Periodontal disease has been considered a systemic exposure implicated in a higher risk of adverse pregnancy outcomes. The aim of the present study was to determine whether maternal periodontitis is associated with an increased risk of preeclampsia. METHODS: A case-control study was conducted in a public hospital in Belo Horizonte, Brazil. During the study period, 588 women, aged 14 to 46 years, were deemed eligible and had data available for analysis. Maternal demographic and medical data were collected from medical records. Preeclampsia was defined as blood pressure >140/90 mm Hg and > or =1+ proteinuria after 20 weeks of gestation. A periodontal examination was performed postpartum. Maternal periodontitis was defined as the presence of four or more teeth with one or more sites with a probing depth > or =4 mm and clinical attachment loss > or =3 mm at the same site. The effects of maternal age, chronic hypertension, primiparity, smoking, alcohol use, and number of prenatal visits were analyzed. Adjusted odds ratios (ORs) for preeclampsia were calculated using multivariate logistic regression. RESULTS: The prevalence of periodontitis was 63.9% and preeclampsia was 18.5%. Variables associated with preeclampsia were chronic hypertension (OR = 4.10; 95% confidence interval [CI] = 2.0 to 8.4; P = 0.001), primiparity (OR = 2.40; 95% CI = 1.5 to 3.9; P = 0.004), maternal age (OR = 1.07; 95% CI = 1.0 to 1.1; P = 0.001), and maternal periodontitis (OR = 1.88; 95% CI = 1.1 to 3.0; P = 0.001). CONCLUSION: Maternal periodontitis was determined to be associated with an increased risk of preeclampsia.     

Effects of plaque disclosing agents on esthetic restorative materials used in pediatric dentistry

The aim of study was to evaluate the color stability of tooth-colored restorative materials usually used in pediatric dentistry after the application of two plaque disclosing agents. Twenty specimens of each material: a resin-modified glass ionomer, a composite resin and an ion-releasing composite resin, were prepared. Baseline color evaluation was performed, samples were exposed to the plaque disclosing agents: a basic fuchsin solution and a fluorescent dye, and new color evaluations were made. The resin-modified glass ionomer stained with basic fuchsin presented the greatest color change in the present study, and the fluorescent dye did not show statistically significant changes among the restorative materials. In conclusion, basic fuchsin dyes should be carefully used in children with a great number of tooth-colored restorations.