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Gustavo Salata Romão,1 Sheyla Ribeiro Rocha,2 Milton Faria Junior,1 Marina de Toledo Durand,1 Reinaldo Bulgarelli Bestetti1 1Medical Course, University of Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil; 2Department of Medicine, Federal University of São Carlos, São Carlos, São Paulo, BrazilCorrespondence: Gustavo Salata Romão; Reinaldo Bulgarelli Bestetti, Email gsalata@uol.com.br; rbestetti44@gmail.comPurpose: To evaluate medical students’ perceptions about using peer teaching (PT) in the online Clinical PBL (C-PBL).Materials and Methods: The C-PBL used in the Primary care Unit (PCU) of the medical course of the Ribeirao Preto University was adapted to the virtual environment. A PT session was included to enhance students’ intrinsic motivation. This cross-sectional study applied a 14-item survey to evaluate the perceptions of 378 medical students from the first to the seventh semester about the use of PT in this context.Results: According to participants’ perceptions, the use of PT in the online C-PBL allowed the interactive participation of students and produced satisfactory knowledge acquisition. Preparing and presenting a slideshow and being taught by peers contributed significantly to their learning. The survey used to collect information presented a high internal consistency measured by Cronbach’s alpha.Conclusion: From the students’ perspectives, the use of PT in the online C-PBL was satisfactory and improved learning for peer teachers and learners. This study contributes additional evidence suggesting that PT is an effective teaching strategy in online learning and can be associated with PBL. This finding has implications for curriculum development and the health system.Keywords: peer teaching, clinical PBL, problem based learning, virtual learning, educational technology

Endodontic retreatment is often necessitated by several factors, including the persistence of microorganisms in the root canal system (RCS). Their complex organization in biofilms increases their pathogenic potential, necessitating new disinfection strategies. This study aimed to standardize a new in vitro protocol for collecting biofilm from the RCS. Thirty-four bovine incisors were used in the study, divided into two experimental groups with two collection steps each: (a) biofilm collection protocol and (b) absorbent paper points protocol. Twelve specimens from each group were selected for counting colony-forming units (CFUs), while eight specimens were prepared for scanning electron microscopy (SEM). Two additional specimens served as sterilization controls to ensure that experiments were free of contamination. The coronal region was removed and standardized at 15 mm. After preparation with ProTaper up to F5, the apical foramen was sealed with composite resin, and the roots were stabilized with acrylic resin in 1.5-mL Eppendorf tubes. The specimens were sterilized and inoculated with Enterococcus faecalis NTCT 775 every 24 h for 21 days. After this period, each group underwent biofilm collection protocols, and CFU and scanning electron microscopy (SEM) data were analyzed. The Shapiro-Wilk test was performed to assess the normality of log-transformed data, and the results indicated a normal distribution for all groups, allowing parametric testing. The Levene test was used to evaluate the equality of variances. The proposed biofilm collection method yielded significantly higher CFU counts compared with the absorbent paper points method, particularly when analyzed on a log₁₀ scale. An independent samples t-test confirmed a statistically significant difference between the two methods (p < 0.0001). The proposed protocol achieved an efficiency rate of 95.85 % ± 1.15 %, whereas the absorbent paper points protocol yielded a lower efficiency of 5.46 % ± 1.37 %. Therefore, the biofilm collection protocol proposed in this study proved to be more effective for biofilm removal from the RCS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background: Chronic Chagas disease (CCHD) associated with Systemic Arterial Hypertension (SAH) is frequently found in areas where the disease is endemic. The pathogenesis of patients with both pathologies (CCHD-SAH) is unsettled. Nitric Oxide (NO) and Kinins are important players in the myocardial inflammation process in experimental CCHD. No previous study has addressed this question in patients with CCHD, particularly in those with CCHD-SAH. Accordingly, this study was undertaken in an attempt to contribute to the understanding of the pathogenesis of patients with CCHD-SAH., Methods: Thirty-seven patients with a positive serology for Chagas disease were enrolled; 15 had CCHD alone, 22 had CCHD-SAH (abnormal ECG/Doppler echocardiogram plus a systolic blood pressure > 140 mmHg or diastolic blood pressure > 90 mmHg on admission), and 11 had SAH alone. Thirty healthy individuals matched by age and sex served as controls. Plasma High-molecular (Hkg) and low-molecular weight (LKg) kininogens, plasma kallikrein levels (Pkal and Tcal), Kininase II, and plasma NO were measured., Results: HKg and LKg were lower in CCHD-SAH patients in comparison with other groups (P < .0001). Pkal and Tcal were higher in CCHD-SAH patients in comparison with the other groups (P< .0001). Kininase II levels were similar in SAH, CCHD, and CCHD-SAH patients, but lower in comparison with controls (P< .0001). NO levels were similar in CCHD and CCHD-SAH patients, but higher in comparison with SAH patients and controls (P > .0001)., Conclusion: Such findings suggest increased Kinin and NO activity in patients with CCHD-SAH, thus contributing to the understanding of the pathogenesis of this condition., (Copyright © 2020 Elsevier Inc. All rights reserved.)