Pseudohyperkalemia in serum: the phenomenon and its clinical magnitude

We investigated in detail the difference between serum and plasma potassium levels in patients with several conditions associated with pseudohyperkalemia. In total, 435 patients with either thrombocytoses, erythrocytoses, leucocytoses, or a mixed-type disorder and 30 healthy controls were included. In each case, the index Dk [serum potassium minus plasma potassium] and the index Dk100 (Dk x 100,000/platelets), which indicates the Dk value that corresponds to platelets of 100,000/mm(3), were estimated. Median Dk was significantly higher in the groups with platelet, erythrocyte, or mixed-type disorders than in the controls (P=0.001). Among these groups, Dk values were significantly higher in patients with thrombocytosis or mixed-type disorders compared with those with erythrocytosis (P<0.001, for both). Furthermore, no significant difference was observed in Dk values between controls and patients with white blood cell disorders (P=0.74). Dk values did not exceed 2.61 mmol/L, whereas Dk100 values were inversely related to platelet counts (r=-0.351, P<0.01). In conclusion, pseudohyperkalemia is mainly present in patients with thrombocytosis or mixed-type disorders, probably as a result of the degranulation of platelets, which offers a potassium load to the surrounding plasma at the time of clot formation in vitro. However, the degree of pseudohyperkalemia does not increase proportionally with the increase of platelet counts, which may be associated with transfer of part of potassium load from the plasma back into red and white blood cells.     

筛选心肌缺血再灌注大鼠差异表达基因

目的：利用抑制性消减杂交技术，筛选出大鼠心肌缺血再灌注的差异表达基因，以期通过基因线索探讨其损伤机制。方法：实验于2006—03／10在中山大学中山医学院完成。①实验分组：Sprague-Dawley雄性大鼠40只，随机分为手术组，对照组，每组20只。②实验干预：手术组结扎左冠状动脉，心电图出现急性心肌梗死改变90min后，去除结扎线，再灌注60min，建立心肌缺血再灌注大鼠模型。对照组仅穿线不结扎，余同手术组。③取缺血区心肌，提取Total RNA，构建cDNA文库，利用抑制性消减杂交技术筛选差异表达基因，测序，登录Genbank寻找同源性基因。结果：共获得124个阳性结果，56个为高表达基因，68个为低表达基因，其中发现5个新的cDNA片段。其中能量代谢、物质运输、信号转导相关差异表达基因分别占所有差异表达基因的39．25％，15．89％，15．89％，并且主要变化为下调。结论：抑制性消减杂交技术是一种高效的筛选差异基因的方法。心肌缺血再灌注后基因变化涉及多种功能的基因，以能量代谢、物质运输、信号转导相关基因下调明显。     

抗癌药物的研究:4-氯苯氧乙酰胺衍生物的合成

Since compounds Ⅲ and Ⅳ possess retinoid-like action and analogues of Ⅰ inhibit some cancer cells ,seventeen derivatives of chlorophenoxy acetamide were synthesized.Of the seven compounds screened ,two exhibit cytostatic activity(1 and　2).Mass spectra showeda　special expulsion of SO2 and CO from the sulfonamide compounds,Nuclear magnetic resonancesplitting patterns of these compounds also showed interesting features.