The Interface between Cytoskeletal Aberrations and Mitochondrial Dysfunction in Alzheimer's Disease and Related Disorders

The major defining pathological hallmarks of Alzheimer's disease (AD) are the accumulations of Abeta in senile plaques and hyperphosphorylated tau in neurofibrillary tangles and neuropil threads. Recent studies indicate that rather than these insoluble lesions, the soluble Abeta oligomers and hyperphosphorylated tau are the toxic agents of AD pathology. Such pathological protein species are accompanied by cytoskeletal changes, mitochondrial dysfunction, Ca2+ dysregulation, and oxidative stress. In this review, we discuss how the binding of Abeta to various integrins, defects in downstream focal adhesion signaling, and activation of cofilin can impact mitochondrial dysfunction, cytoskeletal changes, and tau pathology induced by Abeta oligomers. Such pathological consequences can also feedback to further activate cofilin to promote cofilin pathology. We also suggest that the mechanism of Abeta generation by the endocytosis of APP is mechanistically linked with perturbations in integrin-based focal adhesion signaling, as APP, LRP, and beta-integrins are physically associated with each other.

Microstructural Change of Implant Surface conditioned with Tetracycline-HCl: SLA and TB surface implant / 대한치주과학회지

Mechanical and chemical methods are the two ways to treat the implant surfaces. By using mechanical method, it is difficult to eliminate bacteria and by-products from the rough implant surface and it can also cause the structural change to the implant surface. Therefore, chemical method is widely used in order to preserve and detoxicate the implant surface more effectively. The purpose of this study is to evaluate the effect of tetracylcline-HCl on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, SLA surface and TiO2blasted surface were used in this study. Implant surface was rubbed with sponge soaked in 50mg/ml tetracycline - HCl solution for 1/2 min., 1 min., 1 1/2 min., 2 min., and 2 1/2min. respectively in the test group and with no treatment in the control group. The sponge was soaked in every 30 seconds. Then, the specimens were processed for scanning electron microscopic observation. Based upon the analysis of photographs by three dentists who are not related with this study, the results were obtained as follows; 1. In the pure titanium machined surfaces, the control specimen showed a more or less rough machined surface composed of alternating positive and negative lines corresponding to grooves and ridges. After treatment, machining line was more pronounced for the control specimens. but in general, test specimens were similar to control. 2. In the SLA surfaces, the control specimen showed that the macro roughness was achieved by large-grit sandblasting. Subsequently, the acid-etching process created the micro roughness, which thus was superimposed on the macro roughness. Irrespective of the application time of 50mg/ml tetracycline - HCl solution, in general, test specimens were similar to control. 3. In the TiO2blasted surfaces, the control specimen showed the rough surface with small pits. The irregularity of the TiO2blasted surfaces with 50mg/ml tetracycline - HCl solution was lessened and the flattened areas got wider after 1 minute.