不同测量仪器和不同IOL屈光度计算公式对硅油填充合并白内障眼IOL屈光度测算的比较

背景 玻璃体切割联合硅油填充眼易诱发和加速白内障的形成，白内障联合硅油取出术前人工晶状体（IOL）屈光度的准确测算是术眼获得术后良好视觉质量的关键。目的 研究不同仪器和不同IOL计算公式在硅油填充合并白内障眼行白内障摘出联合IOL植入术前IOL屈光度测算的差异，并测算术前预测IOL屈光度与术后术眼屈光度的误差，为临床相关工作提供参考依据。方法 采用前瞻性非随机对照的研究方法，于2011年8月至2013年10月在苏州大学附属第二医院连续纳入玻璃体切割术后硅油填充合并白内障者36例36眼，患眼均于硅油乳化后4个月～2年拟行白内障超声乳化＋IOL植入＋硅油取出术，术前分别用IOLMaster及A型超声联合手动角膜曲率计（MK）测量术眼眼轴长度（AL）、角膜曲率（CC）和前房深度（ACD）等生物学参数，分别采用SRK-Ⅱ、SRK/T、Hoffer Q、Holladay 1和Haigis计算公式和预留的屈光度计算拟植入的IOL屈光度，分析和比较IOLMaster及A型超声联合MK用上述计算公式测算的IOL理论屈光度值与术后术眼实际屈光度值的平均预测误差（MPE）和平均绝对屈光误差（MAE）。结果 A型超声＋MK和IOLMaster测得的AL分别为（25.21±1.02）mm和（25.43±0.90）mm，ACD分别为（3.07±0.62）mm和（3.22±0.38）mm，A型超声＋MK测量的AL和ACD值明显小于IOLMaster测量结果，差异均有统计学意义（均P＝0.000）。IOLMaster与A型超声＋MK测得的CC分别为（44.58±1.57）D和（44.56±1.62）D，差异无统计学意义（P＝0.568）。用IOLMaster测量时，SRK/T公式的MAE明显小于SRK-Ⅱ、Hoffer Q、Holladay 1和Haigis公式的MAE，差异均有统计学差异（P＝0.017、0.009、0.012、0.001）；Haigis公式的MAE明显大于SRK-Ⅱ、Hoffer Q和Holladay 1公式的MAE，差异均有统计学意义（P＝0.026、0.035、0.021）。用A型超声＋MK测量时，Haigis公式的MAE明显大于与SRK-Ⅱ、SRK/T、Hoffer Q和Holladay 1公式的MAE，差异均有统计学意义（P＝0.007、0.004、0.018、0.006）。用SRK-Ⅱ、SRK/T、Hoffer Q和Holladay 1公式计算时，IOLMaster与A型超声＋MK间测量的MAE≤1.0 D眼数比较差异均无统计学意义（χ2＝0.107、2.250、0.845、0.084，均P〉0.05）；用Haigis公式计算时，IOLMaster测量的MAE≤1.0 D眼数明显多于A型超声＋MK测量结果，差异有统计学意义（χ2＝4.431，P＝0.035）。结论 使用IOLMaster时SRK/T公式测算的IOL屈光度准确性最高，用A型超声＋MK测量时推荐使用SRK-Ⅱ、SRK/T、Hoffer Q和Holladay 1测算公式。

Silicon Affects Transcellular and Apoplastic Uptake of Some Nutrients in Plants

The positive effects of silicon(Si) on growth of plants have been well documented;however,the impact of Si on plant nutrient uptake remains unclear.The growth,nutrient content and uptake of wheat(Triticum aestivum L.),canola(Brassica napus L.) and cotton(Gossypium hirsutum L.) plants were evaluated with or without application of 1.5 mmol L^(-1) Si.Application of Si increased dry weights by 8%,30%and 30%and relative growth rate(RGR) by 10%,13%and 17%in the cotton,canola and wheat plants,respectively.The plant relative water content(RWC) was also increased,but the plant transpiration was decreased by Si application.The uptake and content of Ca^(2+) were 19%and 21%lower in the cotton and wheat plants with Si than those without Si,respectively;however,Si application increased both K^+ and Fe uptake and contents in all plant species.Silicon application reduced B uptake and content only in cotton and increased P and Zn^(2+) contents in all three plant species.The decrease in Ca^(2+) uptake by Si application was sustained even in the presence of metabolic inhibitors 2,4-dinitrophenol and sodium cyanide.Uptake of Ca^(2+) by Si application was enhanced or did not change when plant shoots were saturated with water vapor or their roots were exposed to low temperature.Thus,Si application increased the uptake of transcellularly transported elements like K^+,P,Zn^(2+) and Fe.In contrast,Ca2+ uptake which occurred via both apoplastic and transcellular pathways was decreased by Si application,possibly through reduction of apoplastic uptake.More efficient nutrient uptake might be another promoting effect of Si on plant growth.