Potential Antigenic Candidates for the Development of Peptide-Based Vaccines to Induce Immunization against Helicobacter pylori Infection in BALB/c Mice.

Helicobacter pylori (H. pylori) has been identified as a group-1 definite carcinogen. As of yet, there is no available vaccine for this microorganism. Our study aimed to identify antigenic peptides in H. pylori using an in silico proteomic approach, and to evaluate their effectiveness as potential vaccine candidates. Four different peptide sequences were prioritized using the reverse vaccinology, namely, CagA1, CagA2, VacA, and SabA. Peptides emulsified with Freunde's adjuvant were used to immunize BALB/C mice. Subcutaneously immunized mice were challenged by oral administration of H. pylori. IgG, IgA, IL4, and IL17 were detected in mice sera. Histopathology of the dissected stomach of vaccinated and control mice were assessed using H&E stain. IgG was significantly higher in mice vaccinated with SabA. IL-4 was significantly increased in CagA1, CagA2, VacA, and SabA vaccinated mice compared to the adjuvant group. Additionally, histopathological examination of gastric tissue showed a protective effect in the vaccinated groups compared to adjuvant and PBS groups. Our findings indicate a promising effect of the tested epitopes, particularly the SabA antigen, to induce an immune response against H. pylori.

Knowledge of dental academics about the COVID-19 pandemic: a multi-country online survey.

BACKGROUND: COVID-19 is a global pandemic affecting all aspects of life in all countries. We assessed COVID-19 knowledge and associated factors among dental academics in 26 countries. METHODS: We invited dental academics to participate in a cross-sectional, multi-country, online survey from March to April 2020. The survey collected data on knowledge of COVID-19 regarding the mode of transmission, symptoms, diagnosis, treatment, protection, and dental treatment precautions as well as participants' background variables. Multilevel linear models were used to assess the association between dental academics' knowledge of COVID-19 and individual level (personal and professional) and country-level (number of COVID-19 cases/ million population) factors accounting for random variation among countries. RESULTS: Two thousand forty-five academics participated in the survey (response rate 14.3%, with 54.7% female and 67% younger than 46 years of age). The mean (SD) knowledge percent score was 73.2 (11.2) %, and the score of knowledge of symptoms was significantly lower than the score of knowledge of diagnostic methods (53.1 and 85.4%, P <  0.0001). Knowledge score was significantly higher among those living with a partner/spouse than among those living alone (regression coefficient (B) = 0.48); higher among those with PhD degrees than among those with Bachelor of Dental Science degrees (B = 0.48); higher among those seeing 21 to 30 patients daily than among those seeing no patients (B = 0.65); and higher among those from countries with a higher number of COVID-19 cases/million population (B = 0.0007). CONCLUSIONS: Dental academics had poorer knowledge of COVID-19 symptoms than of COVID-19 diagnostic methods. Living arrangements, academic degrees, patient load, and magnitude of the epidemic in the country were associated with COVD-19 knowledge among dental academics. Training of dental academics on COVID-19 can be designed using these findings to recruit those with the greatest need.

Perceived Preparedness of Dental Academic Institutions to Cope with the COVID-19 Pandemic: A Multi-Country Survey.

Dental academic institutions are affected by COVID-19. We assessed the perceived COVID-19 preparedness of these institutions and the characteristics of institutions with greater perceived preparedness. An international cross-sectional survey of dental academics was conducted from March to August 2020 to assess academics' and institutional attributes, perceived preparedness, and availability of infection prevention and control (IPC) equipment. Principal component analysis (PCA) identified perceived preparedness components. Multilevel linear regression analysis assessed the association between perceived preparedness and fixed effect factors (academics' and institutions' attributes) with countries as random effect variable. Of the 1820 dental academics from 28 countries, 78.4% worked in public institutions and 75.2% reported temporary closure. PCA showed five components: clinic apparel, measures before and after patient care, institutional policies, and availability of IPC equipment. Significantly less perceived preparedness was reported in lower-middle income (LMICs) (B = -1.31, p = 0.006) and upper-middle income (UMICs) (B = -0.98, p = 0.02) countries than in high-income countries (HICs), in teaching only (B = -0.55, p < 0.0001) and in research only (B = -1.22, p = 0.003) than teaching and research institutions and in institutions receiving ≤100 patients daily than those receiving >100 patients (B = -0.38, p < 0.0001). More perceived preparedness was reported by academics with administrative roles (B = 0.59, p < 0.0001). Academics from low-income countries (LICs) and LMICs reported less availability of clinic apparel, IPC equipment, measures before patient care, and institutional policies but more measures during patient care. There was greater perceived preparedness in HICs and institutions with greater involvement in teaching, research, and patient care.

Behavior change due to COVID-19 among dental academics-The theory of planned behavior: Stresses, worries, training, and pandemic severity.

OBJECTIVE: COVID-19 pandemic led to major life changes. We assessed the psychological impact of COVID-19 on dental academics globally and on changes in their behaviors. METHODS: We invited dental academics to complete a cross-sectional, online survey from March to May 2020. The survey was based on the Theory of Planned Behavior (TPB). The survey collected data on participants' stress levels (using the Impact of Event Scale), attitude (fears, and worries because of COVID-19 extracted by Principal Component Analysis (PCA), perceived control (resulting from training on public health emergencies), norms (country-level COVID-19 fatality rate), and personal and professional backgrounds. We used multilevel regression models to assess the association between the study outcome variables (frequent handwashing and avoidance of crowded places) and explanatory variables (stress, attitude, perceived control and norms). RESULTS: 1862 academics from 28 countries participated in the survey (response rate = 11.3%). Of those, 53.4% were female, 32.9% were <46 years old and 9.9% had severe stress. PCA extracted three main factors: fear of infection, worries because of professional responsibilities, and worries because of restricted mobility. These factors had significant dose-dependent association with stress and were significantly associated with more frequent handwashing by dental academics (B = 0.56, 0.33, and 0.34) and avoiding crowded places (B = 0.55, 0.30, and 0.28). Low country fatality rates were significantly associated with more handwashing (B = -2.82) and avoiding crowded places (B = -6.61). Training on public health emergencies was not significantly associated with behavior change (B = -0.01 and -0.11). CONCLUSIONS: COVID-19 had a considerable psychological impact on dental academics. There was a direct, dose-dependent association between change in behaviors and worries but no association between these changes and training on public health emergencies. More change in behaviors was associated with lower country COVID-19 fatality rates. Fears and stresses were associated with greater adoption of preventive measures against the pandemic.

In-vivo assessment of the osteo-protective effects of eugenol in alveolar bone tissues.

Estrogen deficiency following menopausal provokes alveolar bone loss, remodeling and inflammation. Eugenol is a phenolic compound with wide dental applications and anti-inflammatory properties. In the present study, the potential protective role of eugenol against alveolar bone deformities was investigated in an ovariectomized (OVX) rodent model. Two doses of eugenol (2.5 and 5 mg/kg/d) were administered to OVX animals for 12 weeks. In Serum, markers of bone metabolism and pro-inflammatory cytokines were estimated using ELISA. Alveolar bone morphometry was analyzed using high-resolution micro-computed tomography (CT). Bone histological analysis (H&E stain) was also performed. Alveolar bone expression of osteoclastogenesis modulating factors, such as osteoprotegerin (OPG), receptor activator of nuclear factor kappa-b ligand (RANKL) and inflammatory mediators, were measured using immunohistochemistry. Eugenol failed to correct elevated body weights and uterine atrophy in OVX rats. The significant elevation of bone metabolic markers and inflammatory cytokines in OVX animals were markedly improved by eugenol treatment, particularly the higher dose. Eugenol treatment considerably attenuated morphometric trabecular alterations of the alveolar bone and improved alveolar resorption and gingival infiltration. Alveolar bone of OVX animals showed augmented expression of RANKL, OPG and inflammatory cytokines, which were corrected by eugenol treatment. Alveolar bone loss and remodeling associated with estrogen insufficiency was ameliorated by eugenol owing to its anti-inflammatory properties, suggesting an extra dental impact for eugenol.

e-Assessment in a Limited-Resources Dental School Using an Open-Source Learning Management System.

e-Assessment provides solutions to some problems encountered in dental students' evaluation. The aim of this study was to evaluate the experience of a limited-resources dental school with e-assessment provided through an open-source learning management system (LMS). Data about users' access and types of e-assessment activities at the Faculty of Dentistry, Alexandria University, Egypt, were obtained from the web-based LMS Moodle. A questionnaire developed to assess students' perceptions of the e-assessment was also sent to students registered in two courses (undergraduate and postgraduate) with the same instructor. The results showed that most e-courses at the school had one form of e-assessment (82%) and, of these, 16.7% had summative assessment activities. There were significant differences among departments in the number of e-courses with e-assessment. One-quarter of e-courses with e-assessment used Moodle quizzes. Of 285 students registered in the two courses that included the questionnaire, 170 responded (response rate=59.6%). The responding students positively perceived the impact of e-assessment on learning and its reliability and security, whereas technical issues and related stresses were negatively perceived. This study suggests that e-assessment can be used at minimal cost in dental schools with limited resources and large class sizes with the least demands on faculty members and teaching staff time. For these schools, an open-source LMS such as Moodle provides formative e-assessment not available otherwise and accommodates various question formats and varying levels of instructors' technical skills. These students seemed to have a positive impression of the e-assessment although technical problems and related stresses are issues that need to be addressed.

Therapeutic efficacy of plasmonic photothermal nanoparticles in hamster buccal pouch carcinoma.

OBJECTIVES: The objective of this study was to assess the short-term effect of plasmonic photothermal therapy (PPTT) on induced hamster buccal pouch (HBP) carcinoma. STUDY DESIGN: Seventy-six Syrian golden male hamsters were used. The induced HBP carcinomas were directly injected with ∼30 nm gold nanospheres followed by 15 min laser exposure (PPTT). RESULTS: PPTT caused rapid growth cessation and dramatic decrease in tumor sizes after 4 weeks of treatment (P < .05) compared to controls. Microscopic and immunohistochemical examination of the tumor biopsies revealed significant differences in the cellular apoptotic index (AI) value and proliferating cell nuclear antigen (PCNA) immunoexpression in PPTT-treated tumor tissue sections compared to controls (P < .05). Survival probability of the treated animals was increased compared to controls (P < .05). CONCLUSION: PPTT proved to be a successful method for treating superficially located HBP carcinomas.