Function and regulation of Aurora/Ipllp kinase family in cell division

During mitosis,the parent cell distributes its genetic materials equally into two daughter cells through chromosome segregation,a complex movements orchestrated by mitotic kinases and its effector proteins.Faithful chromosome segregation and cytokinesis ensure that each daughter cell receives a full copy of genetic materials of parent cell.Defects in these processes can lead to aneuploidy or polyploidy.Aurora/Ipllp family, a class of conserved serine/threonine kinases,plays key roles in chromosome segregation and cytokinesis.This article highlights the function and regulation of Aurora/Ipllp family in mitosis and provides potential links between aberrant regulation of Aurora/Ipllp kinases and pathogenesis of human cancer.

Potential involvement of leptin in carcinogenesis of hepatocellular carcinoma

AIM: To investigate the potential involvement of leptin in carcinogenesis of hepatocellular carcinoma (HCC) and to elucidate the etiology, carcinogenesis and progress of HCC.METHODS: Expressions of Ob gene product, leptin and its receptor, Ob-R were investigated in 36 cases of HCC spedmens and corresponding adjacent non-tumorous liver tissues with immunohistochemical staining. The effect of leptin on proliferation of Chang liver cell line and liver cancer cell line SMMC-7721 was studied with cell proliferation assay (MTT).RESULTS: Leptin expression was detected in 36 cases of adjacent non-tumorous liver tissues (36/36,100%) with moderate (++) to strong (+++) intensity; and in 72.22%(26/36) of HCC with weaker (+) intensity (P<0.05). Thirty of 36 (83.33%) cases of adjacent non-tumorous liver tissues were positive for Ob-R, with moderate (++) to strong (+++) intensity. In HCC, 11/36 (30.56%) cases were positive, with weak (+) intensity (P<0.05). In cell proliferation assay, leptin inhibited the proliferation of Chang liver cells. The cell survival rate was 10-13% lower than that of the untreated cells (P>0.05). Leptin had little effect on the proliferation of liver cancer cells (/)>0.05).CONCLUSION: High level expression and decreased or absent expression of leptin and its receptor in adjacent non-tumorous liver cells and HCC cells, inhibitory effect of leptin on the proliferation of normal Chang liver cells and no effect of leptin on proliferation of liver cancer cells,may provide new insights into the carcinogenesis and progression of human HCC. It could be assumed that leptin acting as an inhibitor and/or promoter, is involved in the process of carcinogenesis and progress of human HCC.

A new three-layer-funnel-shaped esophagogastric anastomosis for surgical treatment of esophageal carcinoma

AIM: To reduce the incidence of postoperative anastomoticleak, stenosis, gastroesophageal reflux (GER) for patientswith esophageal carcinoma, and to evaluate the conventionalmethod of esophagectomy and esophagogastroplastymodified by a new three-layer-funnel-shaped (TLF)esophagogastric anastomotic suturing technique.METHODS: From January 1997 to October 1999, patientswith clinical stage Ⅰ and Ⅱ (Ⅱa and Ⅱb) esophagealcarcinoma, which met the enrollment criteria, were surgicallytreated by the new method (Group A) and by conventionaloperation (Group B). All the patients were followed at leastfor 6 months. Postoperative outcomes and complicationswere recorded and compared with the conventional methodin the same hospitals and with that reported previously byMcLarty etalin 1997 (Group C).RESULTS: 58 cases with stage Ⅰ and Ⅱ (Ⅱa and Ⅱb)esophageal carcinoma, including 38 males and 20 femalesaged from 34 to 78 (mean age: 57), were surgically treatedby the TLF anastomosis and 64 by conventional method inour hospitals from January 1997 to October 1999. The qualityof swallowing was improved significantly (Wilcoxon W＝2 142,P＝0.0 001) 2 to 3 months after the new operation in GroupA. Only one patient had a blind anastomatic fistula diagnosedby barium swallow test 2 months but healed up 3 weekslater. Postoperative complications occurred in 25 (43 %)patients, anastomotic stenosis in 8 (14 %), and GER in 13(22 %). The incidences of postoperative anastomotic leak,stenosis and GER were significantly decreased by the TLFanastomosis method compared with that of conventionalmethods (x2＝6.566, P ＝0.038; x2＝10.214, P＝ 0.006;x2＝21.265, P＝0.000).CONCLUSION: The new three-layer-funnel-shapedesophagogastric anastomosis (TLFEGA) hasmore advantagesto reduce postoperative complications of anastomotic leak,stricture and GER.

Batch Process Modelling and Optimal Control Based on Neural Network Model

This paper presents several neural network based modelling, reliable optimal control, and iterative learning control methods for batch processes. In order to overcome the lack of robustness of a single neural network, bootstrap aggregated neural networks are used to build reliable data based empirical models. Apart from improving the model generalisation capability, a bootstrap aggregated neural network can also provide model prediction confidence bounds. A reliable optimal control method by incorporating model prediction confidence bounds into the optimisation objective function is presented. A neural network based iterative learning control strategy is presented to overcome the problem due to unknown disturbances and model-plant mismatches. The proposed methods are demonstrated on a simulated batch polymerisation process.

Dynamic distribution of TTK in HeLa cells: insights from an ultrastructural study

Entry into mitosis is driven by signaling cascades of mitotic kinases.Our recent studies show that TTK,a kinetochore-associated protein kinase,interacts with CENP-E,a mitotic kinesin located to corona fiber ofkinetochore.Using immunoelectron microscopy,here we show that TTK is present at the nuclear pore adjacent complex of interphase HeLa cells.Upon nuclear envelope fragmentation,TTK targets to the outermostregion of the developing kinetochores ofmonoorient chromosome as well as to spindle poles.After stable attachment,throughout chromosome congression,TTK is a constituent of the corona fibers,extending up to 90 nm away from the kinetochore outer plate.Upon metaphase alignment,TTK departs from the kinetochore and migrates toward the centrosomes.Taken together,this evidence strongly supports a model in which TTK functions in spindle checkpoint signaling cascades at both kinetochore and centrosome.

Analysis of the thermal profile of work rolls in the hot strip rolling process

A 2-dimension axisymmetric model was developed by the finite-differencemethod, which can be used to predict the transient temperature field and thermal profile of workrolls in the hot strip rolling process. To demonstrate the accuracy and reliability of the solutiondeveloped, the calculation results were compared with the production data of a 1700 mm hot striprolling mill and good agreement was found between them. The effect of strip width and roll shiftingon the thermal expansion of the work rolls was studied. It is found that the strip width has markedeffect on the efficient thermal crown. Initially, when the rolling strip changes from narrow towide, a bigger efficient thermal crown can be quickly achieved; afterwards, when the rolling stripchanges from wide to narrow, not only the influence of uneven wear can be reduced but also theexcessive efficient thermal crown can be avoided. It is also found that the work roll shifting has adeterminate but not obvious effect on the reduction of the efficient thermal crown, and will makethe strip shape unstable without being used properly.

非线性折射波旅行时层析

实现非线性折射波旅行时层析的几个重要问题已得到了验证,它们是折射波旅行时和射线路径计算的精度,折射波旅行时曲线的物理特性和折射波旅行时误差的特性。由此,我们开发了一种带有优化节点分布的最短路径射线追踪方法,它能精确地计算任何速度模型中折射波旅行时和射线路径。我们发现地震折射法中由短和长射线引起的构造多解性会大大影响反演结果。因此,我们提出了这样一种非线性反演方法,它明显地减小了平均慢度(旅行时与相应射线长度的比率)和视慢度(旅行时对距离的导数)的闭合差。结果,既改善了分辨率也提高了收敛速度。为规范化反演问题,我们使用了Tikhonov方法来避免解病态的反演问题,折射旅行时误差以共炮点误差和相对旅行时梯度误差来表征,共炮点误差即来自同一炮记录的偏差为一常数,而后者与旅行时曲线的真实梯度相比具有零均值。因此,我们使用非线性蒙特卡罗方法来量度我们的层析解的不定性,并计算了与两种不同类型的随机数据向量和一个随机模型向量有关的后验模型协方差。非线性不定性分析表明,层析解的分辨率也许与射线路径不对应。我们把这种层析技术用于马萨诸塞州波士顿市附近的一个煤矿的浅层速度构造成像。