The application of subspace preconditioned LSQR algorithm for solving the electrocardiography inverse problem

Regularization is an effective method for the solution of ill-posed ECG inverse problems, such as computing epicardial potentials from body surface potentials. The aim of this work was to explore more robust regularization-based solutions through the application of subspace preconditioned LSQR (SP-LSQR) to the study of model-based ECG inverse problems. Here, we presented three different subspace splitting methods, i.e., SVD, wavelet transform and cosine transform schemes, to the design of the preconditioners for ill-posed problems, and to evaluate the performance of algorithms using a realistic heart-torso model simulation protocol. The results demonstrated that when compared with the LSQR, LSQR-Tik and Tik-LSQR method, the SP-LSQR produced higher efficiency and reconstructed more accurate epcicardial potential distributions. Amongst the three applied subspace splitting schemes, the SVD-based preconditioner yielded the best convergence rate and outperformed the other two in seeking the inverse solutions. Moreover, when optimized by the genetic algorithms (GA), the performances of SP-LSQR method were enhanced. The results from this investigation suggested that the SP-LSQR was a useful regularization technique for cardiac inverse problems.     

Prognostic value of PRL-3 overexpression in early stages of colonic cancer

Aims:  High expression of phosphatase of regenerating liver (PRL-3) has been implicated in cancer invasion and metastasis, indicating a close link between PRL-3 and cancer development. The aim was to investigate the significance of PRL-3 expression in the prognosis of colonic cancer.
Methods and results:  Expression of PRL-3 protein in tissue slides obtained from surgical resection of primary colonic cancer was measured by immunohistochemistry using a specific anti-PRL-3 monoclonal antibody. Archived tissue specimens from 273 colonic cancers and 236 matched specimens of adjacent normal colonic mucosa with a median follow-up of 57 months were examined. Multivariate analysis showed that PRL-3 was an independent prognostic marker for disease-free survival [DFS; hazard ratio (HR) 1.538, P  = 0.035]. More importantly, the expression of PRL-3 showed significant negative correlation with DFS ( P  = 0.018) in patients in the early stages (stage I and II). Patients with high levels of PRL-3 expression in the adjacent normal mucosa also had a significant worse survival rate (DFS 0.0% versus 74.4%, P  = 0.001), and PRL-3 expression remained an independent prognostic marker for DFS (HR 3.0, 95% confidence interval 1.7, 5.3, P  < 0.001).
Conclusions:  PRL-3 may predict poor survival and act as a promising biomarker for individualized therapy for patients with colonic cancer, especially for those diagnosed at an early stage.     

Phospho-CRKL monitoring for the assessment of BCR-ABL activity in imatinib-resistant chronic myeloid leukemia or Ph+ acute lymphoblastic leukemia patients treated with nilotinib

Actual BCR-ABL kinase inhibition in vivo as determined by phospho-CRKL (pCRKL) monitoring has been recognized as a prognostic parameter in patients with chronic myelogenous leukemia treated with imatinib. We report a biomarker sub-study of the international phase I clinical trial of nilotinib (AMN107) using the established pCRKL assay in imatinib-resistant chronic myeloid leukemia or Ph+ acute lymphoblastic leukemia. A minimum dose (200 mg) required for effective BCR-ABL inhibition in imatinib resistant/intolerant leukemia was determined. The pre-clinical activity profile of nilotinib against mutant BCR-ABL was largely confirmed. Substantial differences between peripheral blood baseline pCRKL/CRKL ratios were observed when comparing chronic myeloid leukemia with Ph+ acute lymphoblastic leukemia. Finally, rapid BCR-ABL-reactivation shortly after starting nilotinib treatment was seen in acute lymphoblastic leukemia patients with progressive disease carrying the P-loop mutations Y253H, E255K, or mutation T315I. Monitoring the actual BCR-ABL inhibition in nilotinib treated patients using pCRKL as a surrogate is a means to establish effective dosing and to characterize resistance mechanisms against nilotinib.     

气囊辅助内镜治疗小肠息肉的临床价值研究

目的：探讨应用气囊辅助内镜（ BAE）治疗小肠息肉的可行性、安全性及临床价值。方法回顾性总结2006年8月至2014年7月对199例小肠息肉患者行BAE检查及内镜下息肉切除治疗情况,评价其可行性、安全性及小肠息肉内镜治疗的临床价值。结果199例小肠息肉患者共接受558例次BAE诊治术,摘除小肠息肉共3391枚,其中直径5～10 mm 801枚（23．62％）,11～30 mm 1887枚（55．65％）,31～50 mm 563枚（16．60％）,＞50 mm 140枚（4．13％）,最大者约为7 cm ×10 cm。发生21例次（3．76％）手术相关并发症,包括15例息肉残根出血和6例肠穿孔。结论 BAE是一种安全有效的小肠息肉治疗方法,对大多数小肠息肉患者,可替代外科手术而作为首选治疗方法,具有较好的临床应用价值及发展前景。     

不同掺杂酸对纤维聚苯胺电化学性能的影响

采用界面聚合法通过不同质子酸掺杂分别制备了平均直径约为50,62,95 nm的纤维聚苯胺。通过傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)、透射电镜(TEM)对其化学组成和微观形貌进行了表征,采用循环伏安、恒流充放电和交流阻抗研究了不同质子酸掺杂纤维聚苯胺的超级电容器电容行为,并利用X射线衍射(XRD)、氮气吸脱附及X射线光电子能谱(XPS)等方法对纤维聚苯胺的微观结构进行了深入研究。结果表明：高氯酸(HClO4)掺杂制备的聚苯胺在0.5 A/g电流密度下的比容量可以达到397 F/g,高于盐酸(HCl, 334 F/g)和樟脑磺酸(HCSA, 383 F/g)掺杂聚苯胺的测试结果,纤维的电化学性能主要受其规整度、孔隙率及掺杂度的影响。     

Transendocardial delivery of autologous bone marrow enhances collateral perfusion and regional function in pigs with chronic experimental myocardial ischemia

OBJECTIVES: We tested the hypothesis that intramyocardial injection of autologous bone marrow (ABM) promotes collateral development in ischemic porcine myocardium. We also defined, in vitro, whether bone marrow (BM) cells secrete vascular endothelial growth factor (VEGF) and macrophage chemoattractant protein-1 (MCP-1). BACKGROUND: The natural processes leading to collateral development are extremely complex, requiring multiple growth factors interacting in concert and in sequence. Because optimal angiogenesis may, therefore, require multiple angiogenic factors, we thought that injection of BM, which contains cells that secrete numerous angiogenic factors, might provide optimal therapeutic angiogenesis. METHODS: Bone marrow was cultured four weeks in vitro. Conditioned medium was assayed for VEGF and MCP-1 and was added to cultured pig aortic endothelial cells (PAEC) to assess proliferation. Four weeks after left circumflex ameroid implantation, freshly aspirated ABM (n = 7) or heparinized saline (n = 7) was injected transendocardially into the ischemic zone (0.2 ml/injection at 12 sites). Echocardiography to assess myocardial thickening and microspheres to assess perfusion were performed at rest and during stress. RESULTS: Vascular endothelial growth factor and MCP-1 concentrations increased in a time-related manner. The conditioned medium enhanced, in a dose-related manner, PAEC proliferation. Collateral flow (ischemic/normal zone X 100) improved in ABM-treated pigs (ABM: 98 +/- 14 vs. 83 +/- 12 at rest, p = 0.001; 89 +/- 18 vs. 78 +/- 12 during adenosine, p = 0.025; controls: 92 +/- 10 vs. 89 +/- 9 at rest, p = 0.49; 78 +/- 11 vs. 77 +/- 5 during adenosine, p = 0.75). Similarly, contractility increased in ABM-treated pigs (ABM: 83 +/- 21 vs. 60 +/- 32 at rest, p = 0.04; 91 +/- 44 vs. 36 +/- 43 during pacing, p = 0.056; controls: 69 +/- 48 vs. 64 +/- 46 at rest, p = 0.74; 65 +/- 56 vs. 37 +/- 56 during pacing, p = 0.23). CONCLUSIONS: Bone marrow cells secrete angiogenic factors that induce endothelial cell proliferation and, when injected transendocardially, augment collateral perfusion and myocardial function in ischemic myocardium.