Influence of orthodontic brackets design and surface properties on the cariogenic Streptococcus mutans adhesion.

Objective: To compare the surface properties of self-ligating metallic (SLM), ceramic esthetic, and conventional metallic (CM) brackets, and evaluate the adhesion of Streptococcus mutans biofilms to their surface, attempting to interpret the correlation between bracket type and enamel demineralization from a microbiological perspective. Materials and methods: Twenty-two brackets of each group were used. The brackets' surface roughness was defined and the bacterial adhesion was performed using the strain S. mutans ATCC25175 with 8 h or 24 h of incubation time. The total bacterial adhesion (TBA) of biofilms was assessed using optical density (OD) methodology. To quantify bacteria viability (BV), the colony forming units (CFU) were counted. A scanning electron microscopy (SEM) observation of biofilms was also performed. Results: Ceramic brackets exhibited significantly higher roughness (0.304) compared to CM (0.090) and SLM (0.067) ones (C > CM = SLM). The data obtained with the TBA and BV tests showed that S. mutans biofilm formed on bracket groups exhibited similar results for both incubation periods. From the SEM images it is possible to observe that biofilm structure formed for 24 h was denser than that for 8 h of incubation with significantly more aggregates and cells for three groups. Conclusion: This in vitro study suggests that despite the higher surface roughness of ceramic brackets, this alone does not influence the adhesion of the S. mutans biofilms. Clinical relevance: From a microbiological perspective, the bracket's design may be more relevant than its surface roughness with respect to the adhesion of cariogenic bacteria biofilm with potential risk to dental enamel integrity.

Kefir modulates gut microbiota and reduces DMH-associated colorectal cancer via regulation of intestinal inflammation in adulthood offsprings programmed by neonatal overfeeding.

Obesity is associated with chronic inflammation, intestinal dysbiosis, and colorectal cancer risk. The anti-cancer effects of kefir are highlighted. Here, lactating Wistar rats were divided into: Normal litter (NL); Kefir normal litter (KNL); Small litter (SL); Kefir small litter (KSL). The NL and SL groups received 1 mL of water/day; KNL and KSL received kefir milk daily (108 CFU/mL) during lactation. After weaning, the pups continued to receive the same treatments until 60 days. At 67 days old, colorectal carcinogenesis was induced through intraperitoneal injection of 1,2-dimethylhydrazine. At 240 days, visceral adipose tissue was higher in SL compared to NL, KNL, and KSL. Kefir intake was found to suppress the number of tumors in both KNL and KSL groups (-100% and -71.43%; p < 0.01, respectively). IL-1ß, IL-6, TNF-α, and NO levels in the colon were higher in the NL and SL compared to the KNL and KSL. The gut microbiota in cecal samples of SL was enriched with Alloprevotella, Acinetobacter, and Bacteroides. In contrast, the cecal contents of KSL and KNL were higher Romboutsia. Thus, neonatal overfeeding leads to greater adiposity, inflammation and number of colon tumors in adulthood. Early-life nutrition based on kefir reverted these alterations.

Viral replication of SARS-CoV-2 could be self-limitative - The role of the renin-angiotensin system on COVID-19 pathophysiology.

Currently, the world is suffering with one of the biggest pandemics of recent history. Caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the coronavirus disease 2019 (COVID-19) is provoking devastating consequences on economic and social fields throughout all continents. Therefore, pathophysiological knowledge about COVID-19 is imperative for better planning of preventive measures, diagnosis, and therapeutics of the disease. Based on previous studies, this work proposes new hypothesis related to the role of the renin-angiotensin system on the pathophysiology of COVID-19, and its purpose is to enrich the discussion and to offer alternative ways for experimental and clinical studies aiming at the formulation of new diagnosis and/or treatment methods.

Beneficial effects of rosuvastatin on aortic adverse remodeling in nitric oxide-deficient rats.

This study aimed to evaluate the effect of rosuvastatin upon structural and ultrastructural aortic remodeling in a rat model of hypertension induced by NO synthase blockade. Wistar rats were divided into 4 groups: Control group (C); control treated with rosuvastatin 20mg/kg/day (CR); L-NAME group 40 mg/kg/day (LN) and L-NAME treated with rosuvastatin (LNR) (same doses). Body mass and blood pressure were measured weekly; the experiment lasted 5 weeks. L-NAME administration augmented blood pressure (BP) in the LN group in comparison to the C group (123.3 vs. 180.5 mm Hg at week 5). In LNR rats, rosuvastatin slightly attenuated BP rise, but it had no effect on the BP of CR group. Intima and media thickening of the thoracic aorta were observed in the LN group, and increased elastic fiber content as well. Rosuvastatin prevented all these alterations as seen in the LNR group. Ultrastructural changes due to L-NAME intake (intracellular vesicles and altered membrane morphology in endothelial cells, extracellular matrix deposition, and cytoplasmatic projections from smooth muscle cells toward the internal elastic lamina) were also prevented by rosuvastatin. All in all, rosuvastatin administration is capable of attenuating ultrastructural aortic wall remodeling in NO-deficient rats despite small changes in blood pressure.