| 1 | 肝内和肝外胆管癌肿瘤抑制基因启动子甲基化分析显示文摘目的 探讨胆管癌的表遗传学改变。方法 用甲基化特异PCR(MSP)法 ,检测了 12个候选肿瘤抑制基因 (APGE cad herin/CDH1,MGMT ,RASSF1A ,GSTP ,RAR β ,p14 ARF,p15 INK4b,p16INK4a,p73 ,hMLH1,DAPK)启动子在 72例胆管癌中的甲基化情况 ,其中肝内和肝外胆管癌各 3 6例 ,10例良性胆管上皮作为对照。结果 85 %的胆管癌至少有一个肿瘤抑制基因的甲基化 ,在胆管癌中 ,肿瘤抑制基因的甲基化顺序是 :RASSF1A(65 %) ,p15 INK4b(5 0 %) ,p16INK4a(5 0 %) ,APC(4 6%) ,E cadherin/CDH1(4 3 %) ,p14 ARF(3 8%) ,p73 (3 6%) ,MGMT(3 3 %) ,hMHL1(2 5 %) ,GSTP(14 %) ,RAR β(14 %)和DAPK(3 %)。虽然单个肿瘤抑制基因的甲基化可见于良性胆管上皮 ,但是多个肿瘤抑制基因的甲基化只见于胆管癌。约 70 %(5 0 /72 )的胆管癌有 3个或 3个以上的肿瘤抑制基因的甲基化 ,5 2 %(3 8/72 )有 4个或 4个以上肿瘤抑制基因的甲基化。多个肿瘤抑制基因的协同甲基化 ,和RASSF1A ,p15 INK4b,p16INK4a和 /或hMHL1密切相关。RASSF1A的甲基化在肝外胆管癌 (83 %)较肝内胆管癌更常见 (4 7%) (P =0 . 0 0 3 ) ,而GSTP更多见于肝内胆管癌(肝内 3 1%,肝外 6%,P =0 . 0 12 ) ,本研究提示肿瘤抑制基因启动子CpG岛的甲基化在胆管癌中是一? | YANG Bin Michael G.House GUO Mingzhou James G.Herman Douglas P.Clark | 2005 | 胃肠病学和肝病学杂志2005，14，1： | 46 |
| 8 | Experimental investigation of sediment transport in partially ice-covered channels显示文摘It is important to understand the effects of ice cover on sediment transport in cold climates,where sub-freezing temperatures affect water bodies for a significant part of the year.The literature contains many studies on sediment transport in open channel flow,and several studies on sediment transport in completely ice-covered flow.There has been little or no research on sediment transport in partially ice-covered channels.In the current study,laboratory experiments were done in a rectangular flume to quantify the impact of border ice presence on the sediment transport rate.The effects of ice cover extent and changing flow strengths on sediment transport distribution also were investigated,and the results were compared to those for fully ice-covered and open channel flow.The ice coverage ratios considered were 0(representing the open water condition),0.25,0.50,0.67,and 1(representing fully ice-covered flow).The partial ice cover was found to impact the sediment transport distribution within the chan-nel.The effect of ice coverage extent on sediment transport distribution was more significant at lower flow strengths and became negligible at higher flow strengths.The conventional equations for sediment transport in open channel flow and fully ice-covered flow that relate the dimensionless bedload trans-port rate to the flow strength were found to be applicable to estimate the total cross-section-averaged bedload transport for partially ice-covered flow when modified appropriately.Empirical coefficients for these equations were determined using the experimental data. | Mina Rouzegar Shawn P.Clark | 2023 | International Journal of Sediment Research2023，38，5： | 0 |
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