Laurencia johnstonii extract reverses early lesions in the K14E7HPV16 murine cervical carcinogenesis model.

Persistent infection with high-risk human papillomavirus (HR-HPV) is a well-established risk factor to the development of cervical intraepithelial neoplasia (CIN), a condition that can progress to cervical cancer (CC) a major health problem worldwide. Recently, there has been growing interest in exploring alternative therapies utilizing natural products, among which is the algae species Laurencia johnstonii Setchell & Gardner, 1924 (L. johnstonii), proposed for the management of precancerous lesions. The aim of this work was to determine the effect of an organic extract from L. johnstonii (ELj) in early cervical lesions (CIN 1). These CIN 1 lesions were generated in a murine model expressing the HR-HPV16 E7 oncoprotein (K14E7HPV transgenic mice) with a single exogenous hormonal stimulus using 17ß-estradiol. The histopathological studies, the determination of cell proliferation and of the apoptotic levels in cervical tissue, showed that, seven doses of ELj (30 mg/kg weight per day diluted in a DMSO-saline solution [1:7]) lead to recovery the architecture of cervical epithelium. Accordingly, in the transgenic mice it was observed a statistically significant decrease of the PCNA expression levels, a marker of cell proliferation, and a statistically significant increase in the apoptosis levels using Caspase 3 as a marker. In addition, we determined the expression levels of the tumor suppressor miR-218 and the oncomiRNA miR-21. Interestingly, our results may suggest that ELj treatment tended to restore the normal expression of both miRNAs as compared with controls being more evident in the non-transgenic induced mice. Differences of p < 0.05 were considered statistically significant through the whole study. Based on these results, we propose that the use of ELj could be an alternative for the treatment of cervical early lesions.

Adverse Effect of Bundle Branch Block on Exercise Performance in Patients with Fontan Physiology: From the Pediatric Heart Network Fontan Public Data Set.

Patients with Fontan physiology have reduced exercise performance compared to their peers as well as a higher incidence of bundle branch block (BBB). This study aims to investigate the association between BBB and exercise performance in the Fontan population through a retrospective review of the Pediatric Heart Network Fontan study public use dataset. "Low Performers" were defined as ≤ 25th percentile (for Fontan patients) for each exercise parameter at anaerobic threshold (AT) for gender and age and "Normal Performers" were all other patients. A total of 303 patients with Fontan physiology who underwent exercise testing reached AT and had complete data for BBB. BBB occurred more frequently in Low Performers for VO2 [OR (95% CI): 2.6 (1.4, 4.8)] and Work [OR (95% CI): 2.7 (1.4, 5.1)], suggesting that BBB in the Fontan population is associated with reduced exercise performance. This data adds to the existing clinical evidence of the adverse effects of conduction abnormalities on single ventricle cardiac output and adds support for consideration of cardiac resynchronization and multi-site ventricular pacing in this patient population.

Effect of chitosan irrigant solutions on the release of bioactive proteins from root dentin.

OBJECTIVE: To identify the effect of two chitosan solutions on the release of root dentin matrix proteins and to describe the chemical changes observed following conditioning with chelating agents. MATERIALS AND METHODS: The release of dentin sialoprotein (DSP), transforming growth factor-beta 1 (TGF-ß1), vascular endothelial growth factor (VEGF), and platelet-derived growth factor-BB (PDGF-BB) with different chelating agents, including ethylenediaminetetraacetic acid (EDTA), chitosan solution (CS), and nanoparticulate chitosan (CSnp), was investigated. DSP was quantified using an enzyme-linked immunosorbent assay (ELISA). TGF-ß1, VEGF, and PDGF-BB were quantified using a cytokine bead panel (CBA). Raman spectroscopy was performed to identify surface chemical changes. Statistical analysis was performed using Kruskal-Wallis test with Mann-Whitney-Wilcoxon rank-sum test (p < 0.05). RESULTS: TGF-ß1, VEGF, and DSP solubilized in all irrigants tested. CSnp showed the highest concentration of DSP. PDGF-BB did not exceed the detection limits. Raman spectroscopy revealed a decrease in the phosphate and carbonate peaks, representing the chelating effect of EDTA, CS, and CSnp. Additionally, CSnp showed the greatest preservation of the amide I and III content. CONCLUSION: Proteins can be released from dentin via EDTA, CS, and CSnp conditioning. Raman spectroscopic revealed changes in the inorganic content of the root dentin after chelation. Furthermore, use of CSnp facilitated a preservation of the organic content. CLINICAL RELEVANCE: Chelation allows the release of proteins, justifying the use of chelating agents in regenerative endodontics. The chitosan-dentin matrix interaction also promotes the protection of the organic content as an additional benefit to its protein releasing effect.

Metabolomic Insights of Biosurfactant Activity from Bacillus niabensis against Planktonic Cells and Biofilm of Pseudomonas stutzeri Involved in Marine Biofouling.

In marine environments, biofilm can cause negative impacts, including the biofouling process. In the search for new non-toxic formulations that inhibit biofilm, biosurfactants (BS) produced by the genus Bacillus have demonstrated considerable potential. To elucidate the changes that BS from B. niabensis promote in growth inhibition and biofilm formation, this research performed a nuclear magnetic resonance (NMR) metabolomic profile analysis to compare the metabolic differences between planktonic cells and biofilms of Pseudomonas stutzeri, a pioneer fouling bacteria. The multivariate analysis showed a clear separation between groups with a higher concentration of metabolites in the biofilm than in planktonic cells of P. stutzeri. When planktonic and biofilm stages were treated with BS, some differences were found among them. In planktonic cells, the addition of BS had a minor effect on growth inhibition, but at a metabolic level, NADP+, trehalose, acetone, glucose, and betaine were up-regulated in response to osmotic stress. When the biofilm was treated with the BS, a clear inhibition was observed and metabolites such as glucose, acetic acid, histidine, lactic acid, phenylalanine, uracil, and NADP+ were also up-regulated, while trehalose and histamine were down-regulated in response to the antibacterial effect of the BS.

Comparison of Central Aortic Pressure between Women with Preeclampsia and Normotensive Postpartum Women from an Urban Region of Western Mexico.

Background and Objectives: Central aortic pressure (CAP) can be measured through noninvasive methods, and CAP wave analysis can provide information about arterial stiffness. The objective of this study was to compare CAP in women with preeclampsia and normotensive postpartum women from an urban region in western Mexico. Materials and Methods: We recruited 78 women in immediate puerperium, including 39 with preeclampsia and 39 with normotension, who received delivery care in our hospital between September 2017 and January 2018. Pulse wave analysis was used to assess central hemodynamics as well as arterial stiffness with an oscillometric device. For this purpose, the measurement of the wave of the left radial artery was obtained with a wrist applanation tonometer and the ascending aortic pressure wave was generated using the accompanying software (V 1.1, Omron, Japan). Additionally, the systolic CAP, diastolic pressure, pulse pressure, heart rate, and rise rate adjusted for a heart rate of 75 bpm were determined. The radial pulse wave was calibrated using the diastolic and mean arterial pressures obtained from the left brachial artery. For all the statistical analyses, we considered p < 0.05 to be significant. Results: The results were as follows: a systolic CAP of 125.40 (SD 15.46) vs. 112.10 (SD 10.12) with p < 0.0001 for women with and without preeclampsia, respectively. Systolic CAP was significantly elevated in women with preeclampsia and could indicate an elevated risk of cardiovascular disease. Conclusion: CAP is an important parameter that can be measured in this group of patients and is significantly elevated in women with postpartum preeclampsia, even when the brachial blood pressure is normal.

Predicting the outcome of initial non-surgical endodontic procedures by periapical status and quality of root canal filling: a cohort study.

To assess the previous periapical status and the quality of root canal filling as predictors of the outcome in initial non-surgical endodontic procedures. A retrospective cohort study was designed in which the presence of a previous periapical lesion was determined radiographically. The quality of the root filling was evaluated in terms of homogeneity, taper, and apical extension. The response variable was dichotomized to success and failure. Bivariate analyzes and a mixed generalized linear model interpreted the association between the explanatory variables and the outcome of the initial non-surgical endodontic procedures. A total of 349 roots were evaluated, and a failure rate of 13.18% was established. Poor filling quality was determined in 8.3% of the roots. As a main result, the presence of a preoperative periapical lesion did not determine a significant risk to the failure of the initial treatment. Unlike, a poor quality of the obturation determined association with an unfavorable outcome like this: (1) homogeneity (OR 2.32; p = 0.0181); (2) taper (OR 5.8; p = 0.0); and, (3) extension (OR 3.41; p = 0.0). Therefore, a significant association between inadequate quality of the root filling and failure of the primary non-surgical endodontic procedures was found. Short length of filling was highly associated with failure. The presence of previous periapical lesion was not found to be a significant predictor for treatment outcomes.

Exploring Antifouling Activity of Biosurfactants Producing Marine Bacteria Isolated from Gulf of California.

Biofouling causes major problems and economic losses to marine and shipping industries. In the search for new antifouling agents, marine bacteria with biosurfactants production capability can be an excellent option, due to the amphipathic surface-active characteristic that confers antimicrobial and antibiofilm activities. The aim of this study was to evaluate the antifouling activity of biosurfactants producing marine bacteria from the Gulf of California. The cell free culture supernatant (CFCS) of Bacillus niabensis (S-69), Ralstonia sp. (S-74) (isolated from marine sediment) and of B. niabensis (My-30) (bacteria associated to the sponge Mycale ramulosa) were screened for production of biosurfactants (using hemolysis and drop collapse test, oil displacement and emulsifying activity). The toxicity and antifouling activity were evaluated against biofoulers (bacteria forming biofilm and macrofoulers) both in laboratory and field assays. The results indicate that all bacteria were biosurfactant producers, but the higher capability was shown by B. niabensis (My-30) with high emulsifying properties (E24) of 71%. The CFCS showed moderate toxicity but were considered non-toxic against Artemia franciscana at low concentrations. In the antifouling assay, the CFCS of both strains of B. niabensis showed the best results for the reduction of the biofilm formation (up 50%) against all Gram-positive bacteria and most Gram-negative bacteria with low concentrations. In the field assay, the CFCS of B. niabensis (My-30) led to the reduction of 30% of biofouling compared to the control. The results indicate that the biosurfactant produced by B. niabensis (My-30) has promising antifouling activity.

Biomimetic Approaches for the Development of New Antifouling Solutions: Study of Incorporation of Macroalgae and Sponge Extracts for the Development of New Environmentally-Friendly Coatings.

Biofouling causes major economic losses in the maritime industry. In our site study, the Bay of La Paz (Gulf of California), biofouling on immersed structures is a major problem and is treated mostly with copper-based antifouling paints. Due to the known environmental effect of such treatments, the search for environmentally friendly alternatives in this zone of high biodiversity is a priority to ensure the conservation and protection of species. The aim of this work was to link chemical ecology to marine biotechnology: indeed, the natural defense of macroalgae and sponge was evaluated against biofoulers (biofilm and macrofoulers) from the same geographical zone, and some coatings formulation was done for field assays. Our approach combines in vitro and field bioassays to ensure the selection of the best AF agent prospects. The 1st step consisted of the selection of macroalgae (5 species) and sponges (2 species) with surfaces harboring a low level of colonizers; then extracts were prepared and assayed for toxicity against Artemia, activity towards key marine bacteria involved in biofilm formation in the Bay of La Paz, and the potency to inhibit adhesion of macroorganisms (phenoloxidase assays). The most active and non-toxic extracts were further studied for biofouling activity in the adhesion of the bacteria involved in biofilm formation and through incorporation in marine coatings which were immersed in La Paz Bay during 40 days. In vitro assays demonstrated that extracts of Laurencia gardneri, Sargassum horridum (macroalgae), Haliclona caerulea and Ircinia sp. (sponges) were the most promising. The field test results were of high interest as the best formulation were composed of extracts of H. caerulea and S. horridum and led to a reduction of 32% of biofouling compared with the control.

The relationship of telomere length to baseline corticosterone levels in nestlings of an altricial passerine bird in natural populations.

BACKGROUND: Environmental stressors increase the secretion of glucocorticoids that in turn can shorten telomeres via oxidative damage. Modification of telomere length, as a result of adversity faced early in life, can modify an individual's phenotype. Studies in captivity have suggested a relationship between glucocorticoids and telomere length in developing individuals, however less is known about that relationship in natural populations. METHODS: In order to evaluate the effect of early environmental stressors on telomere length in natural populations, we compared baseline corticosterone (CORT) levels and telomere length in nestlings of the same age. We collected blood samples for hormone assay and telomere determination from two geographically distinct populations of the Thorn-tailed Rayadito (Aphrastura spinicauda) that differed in brood size; nestlings body mass and primary productivity. Within each population we used path analysis to evaluate the relationship between brood size, body mass, baseline CORT and telomere length. RESULTS: Within each distinct population, path coefficients showed a positive relationship between brood size and baseline CORT and a strong and negative correlation between baseline CORT and telomere length. In general, nestlings that presented higher baseline CORT levels tended to present shorter telomeres. When comparing populations it was the low latitude population that presented higher levels of baseline CORT and shorter telomere length. CONCLUSIONS: Taken together our results reveal the importance of the condition experienced early in life in affecting telomere length, and the relevance of integrative studies carried out in natural conditions.

A simultaneous examination of two forms of working memory training: Evidence for near transfer only.

The efficacy of working-memory training is a topic of considerable debate, with some studies showing transfer to measures such as fluid intelligence while others have not. We report the results of a study designed to examine two forms of working-memory training, one using a spatial n-back and the other a verbal complex span. Thirty-one undergraduates completed 4 weeks of n-back training and 32 completed 4 weeks of verbal complex span training. We also included two active control groups. One group trained on a non-adaptive version of n-back and the other trained on a real-time strategy video game. All participants completed pre- and post-training measures of a large battery of transfer tasks used to create composite measures of short-term and working memory in both verbal and visuo-spatial domains as well as verbal reasoning and fluid intelligence. We only found clear evidence for near transfer from the spatial n-back training to new forms of n-back, and this was the case for both adaptive and non-adaptive n-back.

Exploring the chemical diversity of Capsicum chinense cultivars using NMR-based metabolomics and machine learning methods.

The habanero pepper (Capsicum chinense) is a prominent spicy fruit integral to the historical, social, cultural, and economic fabric of the Yucatan peninsula in Mexico. This study leverages the power of 1H NMR spectroscopy coupled with machine learning algorithms to dissect the metabolomic profile of eleven C. chinense cultivars, including those grown by INIFAP (Habanero-Jaguar, Antillano-HRA 1-1, Antillano-HRA 7-1, Habanero-HAm-18A, Habanero-HC-23C, and Jolokia-NJolokia-22) and commercial hybrids (Habanero-Rey Votán, Habanero-Kabal, Balam, USAPR10117, and Rey Pakal). A total of fifty metabolites, encompassing sugars, amino acids, short-chain organic acids, and nucleosides, were identified from the 1H NMR spectra. The optimized machine learning model proficiently predicted the similarity percentage between the INIFAP-grown cultivars and commercial hybrids, thereby facilitating a comprehensive comparison. Biomarkers unique to each cultivar were delineated, revealing that the Habanero-Rey Votán cultivar is characterized by the highest concentration of sugars. In contrast, the Balam cultivar is rich in amino acids and short-chain organic acids, sharing a similar metabolomic profile with the Jolokia-NJolokia-22 cultivar. The findings of this study underscore the efficacy and reliability of NMR-based metabolomics as a robust tool for differentiating C. chinense cultivars based on their intricate chemical profiles. This approach not only contributes to the scientific understanding of the metabolomic diversity among habanero peppers but also holds potential implications for food science, agriculture, and the culinary arts.

Post-treatment Apical Periodontitis in Primary Non-surgical Root Canal Treatment: A Multiple Correspondence Analysis.

Introduction: The presented study aimed to characterise periapical disease in teeth with primary non-surgical root canal treatment in persistent or emergent categories and their risk association. Methods: A retrospective observational study that evaluated permanent teeth with primary non-surgical root canal treatment, was conducted clinically and radiographically for over one year. The following variables were analysed: gender, age, type and location of tooth, previous diagnosis, treatment conditions, and type of coronal restoration. The supplementary variables included the perspectives of the treatment outcome, such as Remains normal, Improvement, and Failure. Statistical analysis was performed using a univariate analysis that estimated the average and proportion for each factor according to the result of the primary non-surgical root canal treatment. The multiple correspondence analysis identified the hierarchy between active variables and their association with the results. Results: A total of 232 teeth in 155 participants were analysed. A χ2 value, (P=0.023) showed that the emergent disease is associated with patients around the age of 50. The multiple correspondence analysis identified a tendency of grouping between the emergent disease and the short filling category, followed by symptomatic pulpitis as a previous diagnosis. The persistent disease was associated with errors and overfillings. An inadequate root filling and taper density adversely impacted the treatment outcome. Conclusions: The length of obturation influenced the presence of failure. Short fillings were associated with emerging periapical disease. Errors and overfillings contributed to the persistent disease in the populations studied.

Intravenous administration of BCG in mice promotes natural killer and T cell-mediated antitumor immunity in the lung.

Intravesical administration of Bacillus Calmette-Guérin (BCG) was one of the first FDA-approved immunotherapies and remains a standard treatment for bladder cancer. Previous studies have demonstrated that intravenous (IV) administration of BCG is well-tolerated and effective in preventing tuberculosis infection in animals. Here, we examine IV BCG in several preclinical lung tumor models. Our findings demonstrate that BCG inoculation reduced tumor growth and prolonged mouse survival in models of lung melanoma metastasis and orthotopic lung adenocarcinoma. Moreover, IV BCG treatment was well-tolerated with no apparent signs of acute toxicity. Mechanistically, IV BCG induced tumor-specific CD8+ T cell responses, which were dependent on type 1 conventional dendritic cells, as well as NK cell-mediated immunity. Lastly, we also show that IV BCG has an additive effect on anti-PD-L1 checkpoint inhibitor treatment in mouse lung tumors that are otherwise resistant to anti-PD-L1 as monotherapy. Overall, our study demonstrates the potential of systemic IV BCG administration in the treatment of lung tumors, highlighting its ability to enhance immune responses and augment immune checkpoint blockade efficacy.

Female Models in AI and the Fight Against COVID-19.

Gender imbalance has persisted over time and is well documented in the fields of science, technology, engineering and mathematics (STEM) and singularly in artificial intelligence (AI). In this article we emphasize the importance of increasing the visibility and recognition of women researchers to attract and retain women in the AI field. We review the ratio of women in STEM and AI, its evolution through time, and the differences among disciplines. Then, we discuss the main sources of this gender imbalance highlighting the lack of female role models and the problems which may arise; such as the so called Marie Curie complex, suvivorship bias, and impostor syndrome. We also emphasize the importance of active participation of women researchers in conferences, providing statistics corresponding with the leading conferences. Finally, to support these views, we give examples of several prestigious female researchers in the field and we review their research work related to COVID-19 displayed in the workshop "Artificial Intelligence for the Fight Against COVID-19" (AI4FA COVID-19), which is an example of a more balanced participation between genders.

Conserved Targets to Prevent Emerging Coronaviruses.

Novel coronaviruses emerged as zoonotic outbreaks in humans in 2003 (SARS), 2012 (MERS), and notably in 2019 (SARS2), which resulted in the COVID-19 pandemic, causing worldwide health and economic disaster. Vaccines provide the best protection against disease but cannot be developed and engineered quickly enough to prevent emerging viruses, zoonotic outbreaks, and pandemics. Antivirals are the best first line of therapeutic defense against novel emerging viruses. Coronaviruses are plus sense, single stranded, RNA genome viruses that undergo frequent genetic mutation and recombination, allowing for the emergence of novel coronavirus strains and variants. The molecular life cycle of the coronavirus family offers many conserved activities to be exploited as targets for antivirals. Here, we review the molecular life cycle of coronaviruses and consider antiviral therapies, approved and under development, that target the conserved activities of coronaviruses. To identify additional targets to inhibit emerging coronaviruses, we carried out in silico sequence and structure analysis of coronavirus proteins isolated from bat and human hosts. We highlight conserved and accessible viral protein domains and residues as possible targets for the development of viral inhibitors. Devising multiple antiviral therapies that target conserved viral features to be used in combination is the best first line of therapeutic defense to prevent emerging viruses from developing into outbreaks and pandemics.

Depth effect on the prokaryotic community assemblage associated with sponges from different rocky reefs.

Background: Sponge microbiomes are essential for the function and survival of their host and produce biologically active metabolites, therefore, they are ideal candidates for ecological, pharmacologic and clinical research. Next-generation sequencing (NGS) has revealed that many factors, including the environment and host, determine the composition and structure of these symbiotic communities but the controls of this variation are not well described. This study assessed the microbial communities associated with two marine sponges of the genera Aplysina (Nardo, 1834) and Ircinia (Nardo, 1833) in rocky reefs from Punta Arena de la Ventana (Gulf of California) and Pichilingue (La Paz Bay) in the coast of Baja California Sur, México to determine the relative importance of environment and host in structuring the microbiome of sponges. Methods: Specimens of Aplysina sp were collected by scuba diving at 10 m and 2 m; Ircinia sp samples were collected at 2 m. DNA of sponge-associated prokaryotes was extracted from 1 cm3 of tissue, purified and sent for 16S amplicon sequencing. Primer trimmed pair-ended microbial 16S rDNA gene sequences were merged using Ribosomal Database Project (RDP) Paired-end Reads Assembler. Chao1, Shannon and Simpson (alpha) biodiversity indices were estimated, as well permutational analysis of variance (PERMANOVA), and Bray-Curtis distances. Results: The most abundant phyla differed between hosts. Those phyla were: Proteobacteria, Acidobacteria, Cyanobacteria, Chloroflexi, Actinobacteria, Bacteroidetes, and Planctomycetes. In Ircinia sp the dominant phylum was Acidobacteria. Depth was the main factor influencing the microbial community, as analysis of similarities (ANOSIM) showed a significant difference between the microbial communities from different depths. Conclusion: Microbial diversity analysis showed that depth was more important than host in structuring the Aplysina sp and Ircinia sp microbiome. This observation contrast with previous reports that the sponge microbiome is highly host specific.

Changes in Toxin Production, Morphology and Viability of Gymnodinium catenatum Associated with Allelopathy of Chattonella marina var. marina and Gymnodinium impudicum.

Allelopathy between phytoplankton organisms is promoted by substances released into the marine environment that limit the presence of the dominating species. We evaluated the allelopathic effects and response of cell-free media of Chattonella marina var. marina and Gymnodinium impudicum in the toxic dinoflagellate Gymnodinium catenatum. Additionally, single- and four-cell chains of G. catenatum isolated from media with allelochemicals were cultured to evaluate the effects of post exposure on growth and cell viability. Cell diagnosis showed growth limitation and an increase in cell volume, which reduced mobility and led to cell lysis. When G. catenatum was exposed to cell-free media of C. marina and G. impudicum, temporary cysts and an increased concentration of paralytic shellfish toxins were observed. After exposure to allelochemicals, the toxin profile of G. catenatum cells in the allelopathy experiments was composed of gonyautoxins 2/3 (GTX2/3), decarcarbamoyl (dcSTX, dcGTX2/3), and the sulfocarbamoyl toxins (B1 and C1/2). A difference in toxicity (pg STXeq cell−1) was observed between G. catenatum cells in the control and those exposed to the filtrates of C. marina var. marina and G. impudicum. Single cells of G. catenatum had a lower growth rate, whereas chain-forming cells had a higher growth rate. We suggest that a low number of G. catenatum cells can survive the allelopathic effect. We hypothesize that the survival strategy of G. catenatum is migration through the chemical cloud, encystment, and increased toxicity.

Observational Fear Learning in Rats: Role of Trait Anxiety and Ultrasonic Vocalization.

Rats can acquire fear by observing conspecifics that express fear in the presence of conditioned fear stimuli. This process is called observational fear learning and is based on the social transmission of the demonstrator rat's emotion and the induction of an empathy-like or anxiety state in the observer. The aim of the present study was to investigate the role of trait anxiety and ultrasonic vocalization in observational fear learning. Two experiments with male Wistar rats were performed. In the first experiment, trait anxiety was assessed in a light-dark box test before the rats were submitted to the observational fear learning procedure. In the second experiment, ultrasonic vocalization was recorded throughout the whole observational fear learning procedure, and 22 kHz and 50 kHz calls were analyzed. The results of our study show that trait anxiety differently affects direct fear learning and observational fear learning. Direct fear learning was more pronounced with higher trait anxiety, while observational fear learning was the best with a medium-level of trait anxiety. There were no indications in the present study that ultrasonic vocalization, especially emission of 22 kHz calls, but also 50 kHz calls, are critical for observational fear learning.

Vertical root fractures: A time-dependent clinical condition. A case-control study in two colombian populations.

BACKGROUND: This nested case-control study can be viewed as an efficient way to sample subjects from a large cohort study case-control study aimed to analyze the effect of different clinical factors on the appearance of vertical root fractures in endodontically-treated teeth (ETT) over time. MATERIAL AND METHODS: By matching 90 cases and 270 controls nested in a cohort of 450 patients. Incident "cases" included those ETT in which a confirmed VRF. The "controls" were ETT with clinical and radiographic evidence of normality. When an "incident case" was detected, three random "controls" according to the evaluation time registered in years were selected. Time interval corresponded to the exposure time from the end of the endodontic treatment until the tooth was included in the study. Demographic and clinical parameters included: age, gender, type, and location of the tooth, type of endodontic treatment, number of appointments necessary to complete the endodontic treatment, use of intra-canal medication, the apical extension of the filling, type of coronal restoration, the role of the tooth in the rehabilitation treatment, presence of intra-radicular posts, and presence of an adjacent implant, were analyzed over time. Statistical analysis: univariate descriptive analysis, Pearson's χ2 test, and a logistic regression model adjusted for the most significant variables with a 95% confidence interval. RESULTS: The prevalence of vertical root fractures was 16.42%. The multivariate analysis confirmed that re-treatment (OR:12.19; OR:4.28;P<0.05) lasting five to ten years and intra-canal medication (OR:6.16;P=0.004) for more than eleven years significantly more associated with the risk of vertical root fracture. For teeth with intra-canal post or direct coronal restorations, the risk of vertical root fracture was three times lower. CONCLUSIONS: Endodontic re-treatment and the use of intracanal medication such as calcium hydroxide should be considered primary and secondary risk factors, respectively, according to the appearance of VRF over time. Key words:Apical surgery, endodontic re-treatment, endodontically-treated teeth, risk factors, vertical root fracture.

Experimental Solution of Chitosan and Nanochitosan on Wettability in Root Dentine: In Vitro Model Prior Regenerative Endodontics.

AIMS: To compare the effect of CS and CSnp on the wettability in root dentine with other irrigation protocols with an experimental in vitro model prior regenerative endodontics. Methods and Material. An in vitro experimental study that included eighty hemisected human root distributed into 8 groups: G1- distilled water; G2- 1% NaOCl/17% EDTA; G3- hypochlorous acid 0.025% HOCl, G4- 1% NaOCl/0.025% HOCl/17% EDTA, G5- 0.2 g/100 mL CS, G6- 1% NaOCl/0.2 g/100 mL CS, G7- CSnp, and G8- 1% NaOCl/CSnp. The wettability analysis calculated the contact angle (θ) between a drop of a blood-like and root dentinal surface; topographic characterization with scanning electron microscopy (SEM) quantified the diameter and number of tubules per area; spectroscopy infrared analyses (IR-S) identified chemical changes in the inorganic (phosphate/carbonate) and organic phase (amide/methyl). Statistical analysis: a linear mixed model, Kruskal-Wallis, and Holm-Bonferroni correction (P < 0.05) were used. RESULTS: Significantly higher wettability for G2 (27.1 (P = 0.0001)) was found. A mean value of 67°±°for experimental groups (P = 0.07) was found, and we did not identify differences between them. The SEM identified greater tubular opening and erosion for G4 and greater dentinal permeability per area for NaOCl/CS. IR-S identified dentinal organic integrity with NaOCl-CS/CSnp compared to organic reduction promoted for NaOCl/EDTA. CONCLUSIONS: This in vitro dentin determined an indirect association between the wettability and organic contents. The oxidative effect of NaOCl could be neutralized by CS-CSnp, and consequently, the wettability of the substrate decreases.