The Unfolded Protein Response in a Murine Model of Alzheimer's Disease: Looking for Predictors.

Alzheimer's disease (AD) represents the most frequent type of dementia worldwide, and aging is the most important risk factor for the sporadic form of the pathology. The endoplasmic reticulum (ER), the main cellular actor involved in proteostasis, appears significantly compromised in AD due to the accumulation of the ß-amyloid (Aß) protein and the phosphorylated Tau protein. Increasing protein misfolding activates a specific cellular response known as Unfolded Protein Response (UPR), which orchestrates the recovery of ER function. The aim of the present study was to investigate the role of UPR in a murine model of AD induced by intracerebroventricular (i.c.v.) injection of Aß1-42 oligomers at 3 or 18 months. The oligomer injection in aged animals induced memory impairment, oxidative stress, and the depletion of glutathione reserve. Furthermore, the RNA sequencing and the bioinformatic analysis performed showed the enrichment of several pathways involved in neurodegeneration and protein regulations. The analysis highlighted the significant dysregulation of the protein kinase RNA-like ER kinase (PERK), inositol-requiring protein 1α (IRE1α) and activating transcription factor 6 (ATF-6). In turn, ER stress affected the PI3K/Akt/Gsk3ß and MAPK/ERK pathways, highlighting Mapkapk5 as a potential marker, whose regulation could lead to the definition of new pharmacological and neuroprotective strategies to counteract AD.

In vitro comparison of shaping abilities of ProTaper and GT rotary files.

This study analyzed the abilities of ProTaper and GT Rotary files to shape the curved canals of extracted mandibular molars. Twenty mesial canals with curvatures ranging from 23 to 54 degrees (Weine analysis) were radiographically selected from a group of 58 molars. The specimens, divided into two groups, were instrumented using the two systems according to the manufacturer's guidelines. Using a radiographic platform and a contrast medium, reproducible preinstrumentation and postinstrumentation radiographs were taken. A computer analysis allowed magnification and superimposition of the images to measure the preparation asymmetry and the linear amount of dentin removal at five points along the canals and to detect canal aberrations. Instrument failures, working time, and working length changes were recorded. The dentin removal and the mean asymmetry showed no significant differences between the two systems. Neither aberrations nor significant changes in working length resulted, but two instruments separated in each group. Working time was shorter for ProTaper files (p < 0.05).

Stability measurements of osseointegrated implants using Osstell in partially edentulous jaws after 1 year of loading: a pilot study.

BACKGROUND: The introduction of resonance frequency analysis (RFA) as a commercially available technique has made it possible to measure implant stability in implant stability quotient (ISQ) units at any time during the course of implant treatment and loading. However, no information on normal ISQ levels can be found in the literature. PURPOSE: The aim of this pilot study was to measure the stability of clinically successful implants in partially edentulous patients after 1 year of loading and to study the influence of jaw, anterior/posterior position, implant length, and marginal bone level on implant stability. MATERIALS AND METHODS: Fourteen partially edentulous patients previously treated with 45 implants were subjected to clinical and radiographic evaluations and RFA measurements using Osstell (Integration Diagnostics, Savedalen, Sweden) after 1 year of loading. RESULTS: All 45 implants were stable, and implant stability levels were in the range of 57 to 82 ISQ units with a mean of 69 +/- 6.5 ISQ after 1 year of loading. Mandibular implants were more stable than were maxillary ones. There were no differences between anterior and posterior implants. No correlation could be found between implant length and stability. Only minor marginal bone resorption was observed. CONCLUSIONS: The results from this limited material showed that successfully integrated implants have ISQ levels from 57 to 82 ISQ with a mean of 69 ISQ after 1 year of loading. Mandibular implants are more stable than are maxillary ones. High implant stability can be achieved with short implants and placement in posterior regions.