Pre-clinical applications of endobronchial ultrasound in lung cancer

© 2018 Dr. Tracy Li-Tsein LeongThe last decade has seen a paradigm shift in the clinical approach to lung cancer. Treatment has evolved from empirical to rational, based on molecular profiling of tissue obtained by minimally invasive techniques such as endobronchial ultrasound (EBUS). However, the stagnantly poor prognosis of lung cancer highlights the ongoing need to improve understanding of the genomic landscape in order to identify novel biomarkers and effective therapeutic strategies. In a series of discrete but inter-related studies, this body of work explored the role that EBUS may play in furthering knowledge in pre-clinical lung cancer research. Parameters of enquiry were established by a systematic review and meta-analysis investigating the ability of systematically performed EBUS to detect occult nodal metastases in patients with a radiologically normal mediastinum. The sensitivity of EBUS for detection of unsuspected nodal disease was 49% (95%CI 41-57%), which was lower than observed for patients with clinically enlarged nodes. Subsequently, work in this thesis focused on lung cancer cases with mediastinal spread where EBUS has established utility. A cohort study addressing the molecular yield of EBUS, demonstrated that a single aspirate returned DNA of sufficient quantity and quality to perform targeted genotyping of lung cancers, including samples with limited tumour cell content. These findings led to a multi-institutional cohort study examining the genomic heterogeneity and evolution of metastatic lung cancer. EBUS was used to sample multiple regions in patients with advanced lung cancer, and whole genome sequencing was performed to generate evolutionary models. Heterogeneity was observed in driver gene mutations between primary and metastatic tumours at single nucleotide variant, insertion/deletion, copy number variant, and structural variant levels. Mutations private to metastatic tumours were associated with a highly diverse somatic mutation signature, most commonly APOBEC. A smoking mutation signature was found highly prevalent in smokers with germline variants in DNA repair genes. Evolutionary modelling suggested that lung cancer precursors accumulated large numbers of mutations before frank malignancy developed. Once established, primary tumours spread to regional lymph nodes rapidly and early in the life of the tumour. While genomic mapping is the first step in development of targeted therapeutics, accurate pre-clinical models are needed to test clinical efficacy. To address deficiencies in existing models of lung cancer, a cohort study was performed to generate patient-derived xenografts of inoperable small cell lung cancer (SCLC) using specimens obtained by EBUS. Viable tumour cells were engrafted into immunodeficient mice with high efficiency, and retained important features of the primary tumour, including mutations characteristic of SCLC. Lastly, ultrasound at low intensities has demonstrated utility as an anti-cancer therapy in a range of cancer cell types cultured in vitro. In a study to explore the potential in lung cancer, both in vitro and in vivo models, including EBUS-generated PDX were subjected to therapeutic ultrasound with cisplatin chemotherapy. In vitro experiments demonstrated increased apoptosis potentiated by chemotherapy combination treatment. However, such findings did not translate to in vivo testing. In summary, this thesis demonstrated that EBUS, a historically diagnostic tool, has value in pre-clinical applications in lung cancer

The Effects of Tobacco and Alcohol Consumption on the Health Costs and the Demand for Health Insurance

[[abstract]]本文使用行政院主計處對於台灣地區人口實施之家庭收支暨個人所得分配調查資料庫（Survey of Family Income and Expenditure），使用1996至2005年的資料進行分析。探討家戶是否有菸類消費或酒類消費，與健康成本的關係。之後再探討是否有菸類消費或酒類消費，與家戶商業保險需求的關係。 本文首先將資料依據是否有酒類消費與是否有菸類消費分組，進行敘述統計分析。得到的初步結論為：無菸酒消費的家戶，醫療支出較其他家戶少約10000元。其次，由於菸酒消費與健康成本間可能存在內生關係，因此使用二階段最小平方法，並使用治療效果模型解決菸酒消費可能存在的樣本選擇問題。 實證結果顯示：菸酒消費與否，對總健康成本有顯著的正相關。除了性別、婚姻狀況、戶長年齡與職業危險度為負相關之外，其他變數皆為顯著正相關。另外，菸酒對於商業型健康保險的需求呈現顯著正相關，顯示台灣商業型健保可能存在菸酒的逆選擇現象。另外，除了婚姻狀況、職業危險性與年齡平方，對於商業型健保需求為負相關之外，其他變數皆為顯著正相關。[[abstract]]This study employs data from Survey of Family Income and Expenditure between 1996 and 2005 The purposes of this study are to discuss the effects of tobacco-consume and alcohol-consume on the health cost and on the demand of health insurance Since alcohol-consume and tobacco-consume in the regression may be endogenous we use instrumental variables and two-stage least squares instead of the ordinary least squares to solve the endogeneity problem inherent the econometric model In addition to accommodate the dichotomous nature of the trouble variable we use treatment effect model to avoid self-selection bias 　　The findings of this study are as follows: First there is significantly positive correlation between the tobacco-consume and the health cost In addition the relation between alcohol-consume and the health cost is also find significantly positive Second both tobacco-consume and alcohol-consume have significantly positive effects on the demand of health insurance which implies the existence of adverse selectio

Blockade of N-type Ca(2+) current by cilnidipine (FRC-8653) in acutely dissociated rat sympathetic neurones

1. The inhibitory effects of cilnidipine (FRC-8653) and various organic Ca(2+) channel blockers on high voltage-activated Ba(2+) currents (HVA I(Ba)) in rat sympathetic neurones were examined by means of the conventional whole-cell patch-clamp recording mode under voltage-clamped conditions. 2. HVA I(Ba) was classified into three different current components with subtype selective peptide Ca(2+) channel blockers. No ω-Agatoxin IVA-sensitive (P-type) or ω-conotoxin MVIIC-sensitive (Q-type) current components were observed. Most (>85%) I(Ba) was found to consist of ω-conotoxin GVIA-sensitive N-type components. 3. The application of cilnidipine inhibited HVA I(Ba) in a concentration-dependent manner. The K(d) value for cilnidipine was 0.8 μM. Cilnidipine did not shift the current-voltage (I-V) relationship for HVA I(Ba), as regards the threshold potential and peak potential where the amplitude reached a maximum. 4. High concentrations of three hypotensive Ca(2+) channel blockers, nifedipine, diltiazem and verapamil, all inhibited HVA I(Ba) in a concentration-dependent manner. The K(d) values for nifedipine, diltiazem and verapamil were 131, 151 and 47 μM, respectively. A piperazine-type Ca(2+) channel blocker, flunarizine, showed a relatively potent blocking action on I(Ba). The K(d) value was about 3 μM. 5. These results thus show that cilnidipine potently inhibits the sympathetic Ca(2+) channels which predominantly consist of an ω-Cg-GVIA-sensitive component. This blockade of the N-type Ca(2+) channel, as well as the L-type Ca(2+) channel by cilnidipine suggests that it could be used therapeutically for treatment of hypersensitive sympathetic disorders associated with hypertension

Las fuentes del realismo mágico en la literatura latinoamericana

El término “realismo mágico” nació en el seno de la cultura europea, pero fueron los escritores y críticos latinoamericanos los que adoptaron este término europeo y lo emplearon para caracterizar su propia literatura. El nacimiento de la cultura latinoamericana reflejado en los textos de los conquistadoresdejó su huella en la cultura latinoamericana y se reprodujo en formas diversas.\ua0Esta memoria se reveló en la época de la madurez de la cultura latinoamericana, cuando en busca de sus raíces se dirigió a sus fuentes. Muchos iniciadores de la nueva novela latinoamericana fueron lectores apasionados de los documentos de la Conquista, donde lo milagroso entró profundamente en el código artístico de la cultura latinoamericana y se definió este modo específico de la percepción de la realidad