Different tau species lead to heterogeneous tau pathology propagation and misfolding.

Tauopathies are a heterogeneous group of pathologies characterized by tau aggregation inside neurons. Most of them are sporadic but certain tauopathies rely on tau gene (MAPT) mutations. They particularly differ from one to another by their different neuropathological signatures e.g. lesion shapes, regions affected and molecular composition of aggregates. Six isoforms of tau exist, but they do not all co-aggregate in each tauopathy but rather have a unique signature for each one. In some tauopathies such as Alzheimer's disease (AD), tau protein aggregation follows stereotypical anatomical stages. Recent data suggest that this progression is due to an active process of tau protein propagation from neuron-to-neuron. We wondered how tau isoforms or mutations could influence the process of tau aggregation and tau propagation. In human neuropathological material, we found that MAPT mutations induce a faster misfolding compared to tau found in sporadic AD patients. In the rat brain, we observed cell-to-cell transfer of non-pathological tau species irrespective of the tested isoform or presence of a mutation. By contrast, we found that the species of tau impact the propagation of tau pathology markers such as hyperphosphorylation and misfolding. Indeed, misfolding and hyperphosphorylated tau proteins do not spread at the same rate when tau is mutated, or the isoform composition is modified. These results clearly argue for the existence of specific folding properties of tau depending on isoforms or mutations impacting the behavior of pathological tau species

Predictors of swallowing outcome in patients treated with surgery and radiotherapy for advanced oral and oropharyngeal cancer

Retaining effective swallowing is a key element when optimising outcomes in the management of head and neck cancer. We report the functional swallowing outcomes for a cohort of 31 individuals with advanced oral and oropharyngeal cancer who underwent free or pedicled flap reconstruction of surgical defects. Swallowing was assessed pre and immediately post surgery and at four months post treatment. Swallowing assessments were related to site, size and volume of defect and composition of flap reconstruction. The effect of radiotherapy on swallowing was assessed among 17 of the 31 individuals who were submitted to radiotherapy after surgery. The proportion of patients on a total oral diet four months post treatment varied significantly by site of defect (Fishers exact test p=0.006), from 100% (7/7) of patients with a lateral defect to only 22% (2/9) of patients with a central defect. The proportion of patients on a total oral diet at the final assessment did not vary by flap reconstruction or radiotherapy

Extracellular vesicles: Major actors of heterogeneity in tau spreading among human tauopathies.

Tauopathies are neurodegenerative diseases characterized by tau inclusions in brain cells. Seed-competent tau species have been suggested to spread from cell to cell in a stereotypical manner, indicating that this may involve a prion-like mechanism. Although the intercellular mechanisms of transfer are unclear, extracellular vesicles (EVs) could be potential shuttles. We assessed this in humans by preparing vesicles from fluids (brain-derived enriched EVs [BD-EVs]). These latter were isolated from different brain regions in various tauopathies, and their seeding potential was assessed in vitro and in vivo. We observed considerable heterogeneity among tauopathies and brain regions. The most striking evidence was coming mainly from Alzheimer's disease where the BD-EVs clearly contain pathological species that can induce tau lesions in vivo. The results support the hypothesis that BD-EVs participate in the prion-like propagation of tau pathology among tauopathies, and there may be implications for diagnostic and therapeutic strategies

Effectiveness of Educational Poster on Knowledge of Emergency Management of Dental Trauma - Part 2: Cluster Randomised Controlled Trial for Secondary School Students

<div><p>Objective</p><p>To investigate the effectiveness of educational poster on improving secondary school students' knowledge of emergency management of dental trauma.</p><p>Methods</p><p>A cluster randomised controlled trial was conducted. 16 schools with total 671 secondary students who can read Chinese or English were randomised into intervention (poster, 8 schools, 364 students) and control groups (8 schools, 305 students) at the school level. Baseline knowledge of dental trauma was obtained by a questionnaire. Poster containing information of dental trauma management was displayed in a classroom for 2 weeks in each school in the intervention group whereas in the control group there was no display of such posters. Students of both groups completed the same questionnarie after 2 weeks.</p><p>Results</p><p>Two-week display of posters improved the knowledge score by 1.25 (p-value = 0.0407) on average.</p><p>Conclusion</p><p>Educational poster on dental trauma management significantly improved the level of knowledge of secondary school students in Hong Kong.</p><p>Trial Registration</p><p><a href="http://www.hkclinicaltrials.com/" target="_blank">HKClinicalTrial.com HKCTR-1343</a></p><p><a href="http://www.clinicaltrials.gov/ct2/show/NCT01809457" target="_blank">ClinicalTrials.gov NCT01809457</a></p></div