In vitro Models of Bone Remodelling and Associated Disorders

Disruption of bone remodelling by diseases such as osteoporosis results in an imbalance between bone formation by osteoblasts and resorption by osteoclasts. Research into these metabolic bone disorders is primarily performed in vivo; however, in the last decade there has been increased interest in generating in vitro models that can reduce or replace our reliance on animal testing. With recent advances in biomaterials and tissue engineering the feasibility of laboratory-based alternatives is growing; however, to date there are no established in vitro models of bone remodelling. In vivo, remodelling is performed by organised packets of osteoblasts and osteoclasts called bone multicellular units (BMUs). The key determinant of whether osteoclasts form and remodelling occurs is the ratio between RANKL, a cytokine which stimulates osteoclastogenesis, and OPG, its inhibitor. This review initially details the different circumstances, conditions, and factors which have been found to modulate the RANKL:OPG ratio, and fundamental factors to be considered if a robust in vitro model is to be developed. Following this, an examination of what has been achieved thus far in replicating remodelling in vitro using three-dimensional co-cultures is performed, before overviewing how such systems are already being utilised in the study of associated diseases, such as metastatic cancer and dental disorders. Finally, a discussion of the most important considerations to be incorporated going forward is presented. This details the need for the use of cells capable of endogenously producing the required cytokines, application of mechanical stimulation, and the presence of appropriate hormones in order to produce a robust model of bone remodelling

Theory of Electron-Phonon Interaction in Semiconductor Superlattices

報告番号: 甲08883 ; 学位授与年月日: 1991-03-29 ; 学位の種別: 課程博士 ; 学位の種類: 理学博士 ; 学位記番号: 博理第2359号 ; 研究科・専攻: 理学系研究科物理学専

Outpatient drainage for patients with spontaneous pneumothorax over 50 years of age

Introduction: The British Thoracic Society has reported a lower success rate for aspiration of spontaneous pneumothorax in patients over 50 years of age. Outpatient drainage therapy is used to manage spontaneous pneumothorax at some institutions. We examined the effect of age on outpatient drainage therapy outcomes. Materials and Methods: We reviewed the records of 68 patients who underwent outpatient drainage therapy with a thoracic vent between December 2012 and April 2015, which included 11 patients over 50 years of age. Indications for outpatient drainage therapy included pneumothorax with no circulatory or respiratory failure and no pleural effusion. Results: Of the 11 patients over 50 years of age, 5 had chronic obstructive pulmonary disease (COPD), one had interstitial pneumonia, one had a history of pulmonary tuberculosis, and one has lung tumors (LTs). Among the 57 younger patients, 2 patients had COPD, and one had LTs. Unexpected hospital admission occurred in 2 patients over 50 years of age and one patient aged 50 years or less (P = 0.0658, Fisher's exact test). Six of the 11 patients over 50 years of age underwent surgery for prolonged air leakage, compared to 8 of the 57 younger patients (P = 0.00695, Fisher's exact test). Conclusions: Outpatient drainage therapy is useful for patients with spontaneous pneumothorax over 50 years of age, because outpatient drainage therapy alone was successful in 4 of 11 patients and admission for drainage was avoided in 9 of 11 patients. However, prolonged air leakage occurs more frequently in this age group

半導体超格子における電子-フォノン相互作用の理論

University of Tokyo (東京大学

Energy renormalization of exciton complexes in GaAs quantum dots

Using GaAs/AlGaAs self-assembled quantum dots we study the few-particle dynamics of fully confined systems, which is associated with purely Coulomb interaction and is not affected by the internal strain field. Systematic evolution in the binding energies of positive and negative trions, as well as biexcitons, with dot size is interpreted in terms of a balance between the Hartree mean-field corrections on single-particle states and the interparticle correlations which lead to a nonseparable dynamics. The experimental behaviors are well reproduced by exact many-body calculations within the framework of the quantum Monte Carlo approach