Monitoring Alzheimer Amyloid Peptide Aggregation by EPR

Plaques containing the aggregated β-Amyloid (Aβ) peptide in the brain are the main indicators of Alzheimer’s disease. Fibrils, the building blocks of plaques, can also be produced in vitro and consist of a regular arrangement of the peptide. The initial steps of fibril formation are not well understood and could involve smaller aggregates (oligomers) of Aβ. Such oligomers have even been implicated as the toxic agents. Here, a method to study oligomers on the time scale of aggregation is suggested. We have labeled the 40 residue Aβ peptide variant containing an N-terminal cysteine (cys-Aβ) with the MTSL [1-oxyl-2,2,5,5-tetramethyl-Δ-pyrroline-3-methyl] methanethiosulfonate spin label (SL-Aβ). Fibril formation in solutions of pure SL-Aβ and of SL-Aβ mixed with Aβ was shown by Congo-red binding and electron microscopy. Continuous-wave 9 GHz electron paramagnetic resonance reveals three fractions of different spin-label mobility: one attributed to monomeric Aβ, one to a multimer (8–15 monomers), and the last one to larger aggregates or fibrils. The approach, in principle, allows detection of oligomers on the time scale of aggregation

Postoperative Study of Bone Gain in Mandibular Alveolar Bone Reconstructed with Screw-Guided Bone Regeneration Technique and Porcine-Derived Xenograft in 42 Edentulous Patient Candidates for Implant-Prosthetic Therapy

This study aimed to test whether alveolar bone gain (width and osteodensity) in mandible implant sites, augmented by the screw-guided bone regeneration (S-GBR) technique and the porcine-derived xenograft, differ from that of the mandible sites reconstructed with S-GBR and the bovine-derived xenograft. Materials and method. A total of 42 edentulous patients (mean age 54.60 ± 14.90) were randomly divided into a test group (S-GBR + porcine-derived xenograft) and a control group (S-GBR + bovine-derived xenograft). The immediate implants were placed simultaneously with grafting procedures. The implant site width was measured before teeth extractions and 6 months after the augmentation procedures. Osteodensity bone values were evaluated immediately after the implant placement and at 6 months follow-up. The CBCT sections and Sidexis XG/DVT (Densply/Sirona) software were used to evaluate the changes of the width in the augmented alveolar bone. The NNT Viewer/CT (NewTom) software was used to record the osteodensity changes. Statistical comparisons between the groups were performed by the Mann–Whitney and t-tests (significance level p < 0.05). Results. The mean values of the bone gain at 6 months follow-up (control group vs. test group) were as follows: width (4.107 mm vs. 4.1624 mm); osteodensity (276.83 HU vs. 254.24 HU). The statistical analysis found the absence of statistically significant differences between the two groups regarding the bone gain (width and osteodensity) at 6 months after the augmentation and the immediate implant placement. Conclusions. The horizontal bone and osteodensity gains in the porcine-derived group were similar and without significant statistical differences when compared with the implant sites reconstructed with the bovine-derived xenografts group at 6 months postoperatively. The reconstruction of the mandibular alveolar bone by the S-GBR technique and the porcine-derived xenografts is a valid bone regeneration strategy for edentulous patients with moderate/severe horizontal resorption of the mandibular alveolar bone

Geomorfološki aspekt antropogenih utjecaja u gorskom području Južnih Karpata (Rumunjska)

This paper deals with some human geomorphological aspects concerning the impact in the alpine area of the Southern Carpathians (Transylvanian Alps). After fi eld investigations and taking into account the major effects of road building, military and mining activities, pasture and tourism activities in the geomorphological landscape we have the possibilities to present a distinct image of some relevant detailed situations. In our opinion the building of roads in the alpine area is by far the most dangerous way of intervention in the geomorphological landscape of the alpine area of the Southern Carpathians. The construction of these roads has altered the profi le of the slope and new scarps have appeared. This situation associated with the vibrations induced by the traffi c favours frost weathering, rock falling and rolling, coupled with the emergence of specifi c deposits and landforms (talus cones and scree) and, of course, with vertical and gully erosion, which is very typical of the area of soft rocks and soils.U članku se analiziraju geomorfološki aspekti antropogenog utjecaja u planinskom području Južnih Karpata (Transilvanske Alpe). Nakon terenskih istraživanja i razmatranja glavnih učinaka gradnje prometnica, vojnih i rudarskih djelatnosti, stočarstva i turizma u krajoliku, iscrpno su opisani konkretni slučajevi. Prema autorovu mišljenju, gradnja prometnica u planinskim područjima daleko je najopasnija intervencija za planinski geomorfološki krajolik Južnih Karpata. Ona je izmijenila profi l padina i stvorila nove strmce. Takvo stanje, povezano s vibracijama od prometa, mehaničkim trošenjem stijena, osipanjem i odronima na padinama, dovelo je do akumulacije specifi čnih taloga i nastanka reljefnih oblika te pojačane erozije tipične za područja mekog tla i stijena