血管紧张素Ⅱ1型受体亚型鉴别的RNAi应用研究

[摘要] 目的 针对小鼠血管紧张素Ⅱ 1型受体(Angiotensin ⅡReceptor 1, AT1R)两亚型之间无工具药区分的现状, 研究应用RNA干扰(RNA interference, RNAi)技术来区分两种亚型受体功能的可行性。方法 选择雄性C57BL小鼠作为动物模型,通过在脑干孤束核（Nucleus Tractus Solitarius,NTS）注射携带短发夹RNA（short hairpin RNA, shRNA）腺病毒的方法,喂养10d后取出脑干组织做标本,使用原位杂交的方法检测每只小鼠脑干NTS部位 AT1R mRNA两种亚型的表达情况,同时使用免疫组织化学的方法显示受体蛋白表达的情况。结果 注入携带针对AT1aR mRNA的shRNA腺病毒后,AT1aR mRNA的表达降低了61.2±6.8%（p<0.01）,AT1bR mRNA的表达则不受影响（p>0.05）;改用AT1bR mRNA相应的shRNA腺病毒, AT1bR mRNA的表达降低了51.6±5.2%（p<0.01）,AT1aR mRNA的表达基本不受影响（p>0.05）。用免疫组织化学显示AT1R蛋白表达情况,发现两种情况下表达均出现不同程度的下降。结论 所设计的针对不同亚型AT1R的shRNA,可以特异地沉默各自不同受体的mRNA表达,并同时在蛋白水平上显示出AT1R受到抑制的结果。可以将其应用于区别AT1R两种亚型受体功能的研究。 [关键词] RNA干扰 血管紧张素 孤束核 受体     

替米沙坦对体外胰岛的第一相胰岛素分泌功能的影响

目的 一些大规模流行病学研究显示血管紧张素(angiotension, Ang)Ⅱ受体拮抗剂能减少2型糖尿病的发生,但其机制尚未阐明.文中旨在探讨替米沙坦(Telmisartan)体外干预对小鼠体外胰岛的第一相胰岛素分泌功能的影响.方法 18只8周龄db/m非糖尿病小鼠,随机分为3组,每组6只,编为A、B、C组.另12只db/db糖尿病小鼠随机分为2组,每组6只,编为D、E组.分离胰岛后,A～E组分别给予含有空白、100nmol/LAngⅡ、10μmol/L替米沙坦+100nmol/LAngⅡ、空白、10μmol/L替米沙坦的培养液孵育及灌流.收集高糖灌流后0～30min各时间点的灌出液,测定胰岛素水平.结果 AngⅡ孵育灌流的db/m小鼠胰岛的胰岛素第一相分泌显著下降,仅达到基础水平的4倍,而预先给予替米沙坦后,AngⅡ孵育灌流的db/m小鼠胰岛的胰岛素第一相分泌明显改善,达到基础水平的7倍左右.db/db小鼠体外胰岛的胰岛素分泌在高糖刺激后胰岛素第一相分泌明显受损,小于基础值的2倍,仅为3μg/L.而替米沙坦孵育灌流的db/db小鼠胰岛的胰岛素分泌在给予16.7mmol/L葡萄糖后1min即达到最高值6μg/L,显示胰岛素第一相分泌明显改善.结论 替米沙坦体外干预阻断局部肾素血管紧张素系统(renin angiotensin system,RAS)活性,显著改善了胰岛β细胞第一时相分泌,保护胰岛功能,这可能是阻断RAS降低糖尿病发病率的保护机制之一.     

血管紧张素Ⅱ对体外人胰岛细胞GLUT-2mRNA表达的影响

目的：探讨血管紧张素Ⅱ（angiotensinⅡ,AngⅡ）对体外人胰岛细胞内葡萄糖转运蛋白2（GLUT-2）mRNA的影响,通过体外实验了解血管紧张素Ⅱ影响胰岛细胞分泌功能的相关分子机制。方法：人胰岛细胞被分成空白对照组,AngⅡ组（100 nmol/L）和氯沙坦组（1μmol/L）,以半定量RT-PCR检测细胞内GLUT-2mRNA的表达情况。结果：在100nmol/L AngⅡ作用下,人胰岛细胞GLUT-2 mRNA的表达显著低下（P〈0.05）;AngⅡ的这种作用,可被氯沙坦部分逆转。结论：AngⅡ可能通过抑制GLUT-2的表达而影响胰岛β细胞胰岛素的分泌。     

依折麦布对db/db糖尿病小鼠胰岛自身胰岛素信号通路的影响

目的：研究依折麦布对db／db糖尿病小鼠胰岛自身胰岛素信号通路的影响。方法：将40只8周龄db／db小鼠随机分为依折麦布组和db／db对照组,每组20只,分别予依折麦布10mg·（kg·d）^-1和安慰剂灌胃。另设20只同周龄db／m小鼠,予安慰剂灌胃作为非糖尿病对照（db／m对照）组。每周监测体重、血糖,投药前及投药后6周测量生理及代谢指标,投药后6周后用蛋白质印迹法检测各组小鼠胰岛中蛋白酪氨酸磷酸酶1B（PTP1B）、葡萄糖转运子（GLUT-2）、葡萄糖激酶（GCK）表达的变化。结果：依折麦布组治疗6周后空腹血糖显著下降,同时总胆固醇及低密度脂蛋白胆固醇低于对照组（P〈0．05）。依折麦布组治疗6周后与db／db对照组比较,PTP1B的表达水平明显下降（P〈0．05）,GLUT-2、GCK表达水平明显升高（P〈0．05）。结论：依折麦布除降低血脂外,还可以改善db／db糖尿病小鼠胰岛自身胰岛素抵抗,促进胰岛素分泌,降低血糖。     

siR N A 干扰 A T1 R 基因调控链脲佐菌素诱导NIT －1细胞凋亡的实验研究

目的：用siRNA干扰技术沉默小鼠胰岛素瘤NIT－1细胞血管紧张素Ⅱ1型受体（ AT1R）基因,探讨其对链脲佐菌素（STZ）诱导的胰岛素瘤细胞凋亡的影响。方法针对小鼠AT1R基因,设计并合成3对siRNA序列,脂质体法转染至NIT－1细胞,荧光显微镜观察荧光强度检测转染效率,Real－time PCR检测AT1R mRNA表达量判断不同干扰序列及干扰时间的基因沉默效果;分4组：空白组不予任何干预,STZ组予5 mmoL／L STZ干预30 min,si－AT1R组予40 nmol／L si－AT1R转染24 h,si－AT1R＋STZ组予40 nmoL／L si－AT1R转染24 h后5 mmoL／L STZ干预30 min;Real－time PCR检测Caspase－3 mRNA表达量,Hoechst33342染色荧光显微镜和Annex-in V－FITC／PI流式细胞术检测细胞凋亡率。结果40 nmol／L siRNA转染的荧光强度最强,转染后AT1R mRNA表达量明显下降,si－AT1R－2转染24 h的沉默效果最佳（92.20％）;Caspase－3 mRNA表达量：STZ组与空白组比增加了2.37倍（P＜0.05）,si－AT1R＋STZ组与STZ组比减少了11.28％,但差异无统计学意义;细胞凋亡率：STZ组与空白组比增加了3.27倍（P＜0.05）,si－AT1R＋STZ组与STZ组比减少了26.82％（P＜0.05）。结论本研究建立了稳定的胰岛细胞AT1R基因沉默模型;RNA干扰沉默胰岛细胞AT1R基因可通过下调Caspase－3 mRNA表达量降低STZ诱导的细胞凋亡率,提示AT1R介导了STZ诱导的胰岛细胞凋亡过程。     

血管紧张素转化酶2减少胰岛细胞的氧化应激及凋亡

目的探讨血管紧张素转化酶2(angiotensin converting enzyme 2,ACE2)在胰岛素分泌中的作用及可能的机制。方法提取C57BL/6小鼠的胰岛,用棕榈酸诱导氧化应激及凋亡。用ACE2及对照GFP的腺病毒对胰岛进行感染。ELISA方法检测胰岛素分泌功能。DHE探针检测活性氧(reactive oxygen species,ROS)浓度。蛋白质印记(Western blotting)方法检测糖代谢及凋亡水平。结果 1)ACE2腺病毒感染后,胰岛素分泌增加。2)ACE2腺病毒感染降低了氧化应激水平。3)ACE2腺病毒感染减低胰岛凋亡。结论 ACE2改善胰岛素分泌功能,其机制可能与ACE2对氧化应激和凋亡的保护作用有关。     

替米沙坦对db/db小鼠胰岛内NADPH氧化酶表达水平的影响

目的大规模流行病学研究显示,血管紧张素ⅡAT1受体拮抗剂（angiotensinⅡAT1receptor antagonist,ARB）能减少2型糖尿病的发生,但其机制尚未阐明。文中拟探讨使用替米沙坦阻断肾素-血管紧张素系统对db/db小鼠胰岛内NADPH氧化酶表达水平的影响。方法将22只8周龄db/db小鼠随机分为2组,替米沙坦组和db/db对照组,每组11只,分别给予替米沙坦5mg/（kg.d）和安慰剂灌胃。另设11只同周龄db/m小鼠也给予安慰剂灌胃作为非糖尿病对照,为db/m对照组。每周监测体重、血糖,6周后行腹腔葡萄糖耐量试验,并取胰腺行免疫组化,分析胰岛内NADPH氧化酶表达情况。结果替米沙坦降低了db/db小鼠血糖,改善胰岛素分泌功能和胰岛素敏感性,显著降低了胰岛内NADPH氧化酶gp91phox、p22phox亚基的表达水平。结论替米沙坦阻断AT1受体可改善胰岛微环境,降低NADPH氧化酶的表达,减少氧化应激的来源,从而保护胰岛β细胞。     

建立离体胰岛灌流系统用于评估胰岛素第一时相分泌功能

目的 建立一套稳定可靠的离体胰岛灌流系统,用于对从动物模型中分离出胰岛的胰岛素第一时相分泌功能的评估.方法 建立离体胰岛灌流系统硬件设备,包括灌流架、输入管道系统、胰岛舱、输出管道系统、恒温水浴系统、微量泵输注系统,共同构成完整的灌流系统.分离胰岛后置于Hank's平衡液,二氧化碳孵箱38℃孵育1 h,将胰岛按每组50个分组.将离体胰岛灌流系统置于37℃水浴,并将微最泵输注系统与其连接.将预先配置好的含2.8 mmol/L葡萄糖的Kerbs-Ringer 碳酸氢盐(ICRB)溶液充填至整个管道系统,在层析柱中加入100μl预先配置好的葡聚糖凝胶,然后将每组50个胰岛转移至层析柱,再加入100μl葡聚糖凝胶.将整个管道系统全部浸入水浴.开始2.8 mmol/L KRB 0.5 ml/h速度灌流1 h,后换为16.7 mmol/L KRB 1 ml/h,以开始16.7 mmol/L KRB灌流为0时间点,在灌流前30、20、10 min、灌流后0、20、40、60、80、100 8和2、3、4、5、7、8、9、10、15、20、25、30 min收集灌流出的液体,-80℃保存后测定胰岛素,根据胰岛素浓度绘制胰岛素第一时相分泌曲线.使用此灌流系统分别对8周龄的db/m和db/db小鼠的胰岛素第一时相分泌进行评估.结果 成功建立离体胰岛灌流系统,并绘制胰岛素第一时相分泌曲线.db/m小鼠离体胰岛在高糖刺激1～2 min时出现最高峰值,达基础水平的7倍左右;而糖尿病db/db小鼠的第一时相分泌显著受损,在整个30 min期间胰岛素浓度仅有轻微上升,是基础值的2.6倍.结论 成功建立的离体胰岛灌流系统,可广泛用于评价离体胰岛的胰岛素第一时相分泌.     

RNA干扰技术下调大鼠血管紧张素Ⅱ1型受体

目的：研究RNA干扰技术对体内外大鼠血管紧张素Ⅱ1型受体（AT1R）基因的沉默作用。方法：人胚肾293细胞扩增Ad5-ATIR—shRNA—EGFP并感染体外培养的c6细胞株,进行RT—PCR和Western—blot检测AT1RmRNA和蛋白的表达。Ad5-AT1R—shRNA—EGFP尾静脉注射法转染SHR,免疫组织化学法测定SHR主要器官：心脏、肝脏、肾脏、肾上腺和主动脉AT1R表达。结果：Ad5-AT1R—shRNA—EGFP显著抑制c6细胞AT1RmRNA及蛋白表达,并显著抑制SHR心脏、肝脏、肾脏、肾上腺、主动脉的AT1R表达。结论：靶向大鼠AT1R基因mRNA的短发夹RNA腺病毒载体,在体外和体内环境下高效特异性抑制靶基因的表达,能达到基因干扰目的。     

脂质体瞬时转染siRNA抑制肾小管上皮细胞AngⅡ 1型受体表达

目的建立有效的脂质体瞬时转染法,转染小分子RNA（siRNA）,抑制人肾小管上皮细胞（human kidneytubular epithelial cells,HKC）血管紧张素Ⅱ（AngⅡ）1型受体（AT1R）的表达。方法针对人AT1R mRNA135到156位点,由美国Ambion公司设计并合成AT1R siRNA序列,以脂质体法瞬时转染至HKC,利用RT-PCR及Western blot技术检测HKC内AT1R mRNA及蛋白表达。结果AT1R siRNA转染对人肾小管上皮细胞AT1R的抑制效果在48h达到最大抑制作用;转染后,HKC细胞AT1R mRNA表达下调（68.5±6.4）%,AT1R蛋白表达下调（80.7±5.3）%,与对照组比较存在显著性差异（P〈0.001）。使用AngⅡ刺激,特异性AT1R siRNA转染组AT1R表达明显下降,无转染及非特异性转染组AT1R表达升高。特异性AT1R siRNA转染HKC细胞后,其炎症因子单核细胞趋化蛋白-1（MCP-1）表达明显下降。结论本研究利用脂质体瞬时转染siRNA方法,成功抑制肾小管上皮细胞表达AT1R,为后续相关研究提供实验方法。     

Value of D-Dimers in patients with acute aortic dissection

Objective: To evaluatel the value of D-dimers in patients with acute aortic dissection (AAD). Methods: This study consisted of 16 patients with AAD and 27 non-AAD patients. Serum D-dimets were measured by Sta-Liatest D-DI immunoturbidimetric assay. Results: D-dimer level was higher (P ＜ 0.001) in patients with AAD(7.91 ± 5.52 μg/ml) than that in non- AAD group(1.57±1.24 μg/ml). D-dimer was positive (＞0.4 μg/ml) in all patients with AAD and in 10 control group patients (37%). Among patients with acute AAD, D-dimers tended to be higher in Stanford A than in Stanford B (8.67 ± 4.31 μg/ml vs. 3.24±1.27 μg/ml, P ＜0.01). D-dimer values tended to be higher in more extended disease(3.84 ± 1.65 μg/ml, 8.57 ± 3.58 μg/ml and 11.87 ± 5.69 μg/ml in thoracic aorta, thoracic and abdominal aorta, thoracic and abdominal aorta and iliacal arteries, respectively, P ＜ 0.05 for both 8.57 ± 3.58 and 11.87 ± 5.69 vs. 3.84 ± 1.65 ). Including the control group into the analysis, we found a sensitivity of 100%, a negative predictive value of 100%, and a specificity of 66% and a positive predictive value of 64% for D-dimer in diagnosis of AAD in our patients with suspected AAD. Conclusion: D-dimer was elevated in patients with AAD. A negative D-dimer test result could be useful in excluding AAD.     

Research of combined liver-kidney transplantation model in rats

Objective： To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods： SD rats served as both donors and recipients. 4℃ sodium lactate Ringer＇s was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava （IVC） inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results： Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion： This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment.     

BLOOD PRESSURE CHANGE WITH AGE IN SALT-SENSITIVE TEENAGERS

Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8±5.2 mmHg, P＜ 0.01; 12.2%± 12.0% vs. 2.5% ±4.4%, P＜ 0.001,respectively). There was a similar trend for diastolic blood pressure (8.4 ± 6.4 mmHg vs. 3.7 ± 6.4 mmHg, P = 0.052; 13.2% ±10.6 % vs. 6.8%± 10.1%, P = 0.053, respectively).Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.     

安心颗粒对急诊经皮冠状动脉介入术后生活质量影响的研究

目的：评价使用安心颗粒对急诊经皮冠状动脉介入术（PPCI）术后生活质量的影响.方法：将160例接受PPCI的急性ST段抬高型心肌梗死患者随机分为安心颗粒组（术前顿服安心颗粒8.8g,术后安心颗粒4.4 g/次,每日2次）和对照组（仅接受基础药物治疗）.所有患者均服用阿司匹林、氯吡格雷和阿托伐他汀.分别在入院时、出院前1d、出院后180 d时,应用心肌梗死多维度量表（MIDAS）、中文版SF-36评价量表对患者生活质量评分.并观察术后30 d以内的出血并发症、血小板减少症发生情况.结果：入院时和出院前1d,两组患者的心肌梗死MIDAS、SF-36量表评分比较无差异（P＞0.05）;出院后180 d时,与对照组比较,安心颗粒组MIDAS、SF-36评分明显减低（P＜0.05）;组内与入院时比较,两组出院前1d、出院后180 d时,MIDAS、SF-36评分均降低（P＜0.05）.两组患者在随访期间均无大量出血、少量出血、重度和极重度血小板减少症发生,安心颗粒组有4例、对照组有7例发生不明显出血（P＞0.05）.两组发生轻度血小板减少症的患者数比较无差异（P＞0.05）.结论：PPCI使用安心颗粒,能改善急性ST段抬高型心肌梗死患者的生活质量,且不增加出血风险.     

The comparative studies of the influences of Urapidil and Nicardipine on sino-atrial node function, atrio-ventricular node function and hemodynamics

Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function,atrio-ventricular node function and hemodynamics.Methods:Thirty-two Angora's rabbits were selected and randomly divided into four groups.U1 group:urapidil 0.25 mg/kg;U2 group:urapidil 0.5 mg/kg;N1 group:nicardipine 10 μg/kg;N2 group:nicardipine 20 μg/kg.All these medicine were administrated within 30 seconds.Measurements were taken before and after the administration of urapidil or nicardipine for the following data:mean blood pressure(MAP),heart rate(HR),sino-atrial conduction time(SACT),maximal sinoatrial recovery time(SNRTmax)corrected sinus node recovery time(CSNRT),index of sinus node recovery time(SNRTI),Wenckebach A-V conduction frequency (WB),and P-R interval.Results:Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine.No significant changes could be found in the rest of the parameters.Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group(P＜0.01);the MAP decreased(P＜0.01)and the HR increased drastically(P＜0.01).Conclusions:Neither urapidil(0.25 mg/kg,0.5 mg/kg)nor nicardipine(10μg/kg,20μg/kg)has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function.Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.     

Expression of OPGmRNA and ODFmRNA in the patients of hip fracture due to osteoporosis

Objective：To investigate the gene expression of osteoprotegerin（OPG） and osteoclast differentiation factor（ODF） in the bone tissue of patients with hip fracture due to osteoporosis. Methods：OPGmRNA and ODFmRNA in the bone tissue in 50 cases of osteoporosis sufferers（over 50 years old） with hip fracture（Observer Group） and 30 cases of hip facture sufferers with no osteoporosis（Control group） were analyzed with the Semi-Quantitative RT-PCR method. Results：The mRNA expressed of ODF, OPG were both high in the patients with hip fracture. In the control group, the expression of OPG mRNA was observed, while the expression of ODF mRNA was very slight. Conclusion：Aged patients contained all signals including OPG, ODF that are essential for inducing osteoclastogenesis and promoting bone resorption.     

The clinicopathological and immuohistochemical analysis of solid-pseudopapillary tumor of the pancreas： report of 9 cases

Objective：To investigate the clinical features, pathological characteristics and immunophenotype of solid-pseudopapillary tumor of the pancreas（SPTP）. Methods：Nine surgically treated cases of SPTP were retrospectively reviewed. Hematoxylin and Eosin（HE） staining and immunohistochemical staining were used to analyze all cases, and the general clinical data was collected. Results：Six patients were asymptomatic except for a palpable mass. Two patients complained of vague-epigastric pain. One patient appeared jaundice. The tumor was encapsulated and solid tissues alternately with cystic tissues. Histologically, the histological structure of solid portion was pseudopapillary with a fibrovascular core. Tumor cells were uniform and medium-sized which were arranged in sheets ets or nests or pseudopapillary patterns. Immunohistochemical studies demonstrated that SPTP proved positive in vimentin（9/9 cases）, AAT（9/9 cases）, NSE（9/9 cases）, ACT（7/9 cases）, CK20（2/9 cases）, CgA（1/9 cases）, S-100（3/gcases）, PR（4/gcases）, Syn（3/9 cases） and CD56（5/9cases）, negative in CEA and ER. Conclusion：SPTP is a tumor predominantly occurring in young women frequently without special symptoms. This tumor has various characteristical histological patterns with different immunophenotype.     

Dynamic Changes in Serum Estradiol and Progesterone levels in Patients of Premenstrual Syndrome with Adverse Flow of Liver-qi

Objective:To probe into the influence of changes of ovarian hormones on the pathogenesis of the specific sub-type premenstrual syndrome(PMS)and reveal partial microcosmic mechanisms of adverse flow of liver-qi.Methods:Estradiol(E2)and progesterone(P)levels in serum were determined at different phases of menstrual cycle by radioimmunoassay.Results:In the group of PMS with adverse flow of liver-qi.the secretive peak value Of E2 and P at the follicular phase significantly decreased,and the secretive peak value at the luteal phase did not come into being.Conclusions:Low E2 and P secretive peak at the follicular phase and absence of secretive peak at the luteal phase is one of the microcosmic mechanisms of PMS with adverse flow of liver-qi.One of the pathophysiologic mechanisms of specific sub-type PMS is probably the continuous low level of E2and P.     

Real-time Three-dimensional Echocardiography in Assessment of Left Ventricular and Right Ventricular Volumes

Real-time three-dimensional echocardiography (RT3DE)is a new ultrasound technique that enables dynamic threedimensional visualization and quantification of the heart in real time. Investigation of feasibility and methodology of RT3DE in determining left ventricular (LV) and right ventricular (RV) volumes, RT3DE was performed in 35 normal adults using Philips SONOS 7500 system with a 2-4 MHz matrix array transducer. The 60°×60° "pyramid" volume database was obtained and analyzed on a TomTec echo workstation. Both LV and RV volumes were calculated with four 3DE methods (i.e. apical 2, 4, 8, and 16-plane) through manually tracing ventricular endocardial borders in end diastole and end systole. Stroke volumes were then calculated. LV volume was also measured by 2DE Simpson's rule using GE VIVID 7 ultrasound machine.     

SCREENING FOR A 21-CHROMOSOME ABNORMALITY IN PREIMPLANTED EMBRYOS OF ELDERLY WOMEN

Increasing maternal age is the only etiological factor unequivocally linked to Down's syndrome in humans. The occurrence rate of newborns with Down's syndrome is about 1/220 in women over 35 years old. However, the occurrence rate in embryos fertilized in vitro, of the elder woman is unclear. Using FISH we screened the number of chromosome 21 in preimplanted embryos of 5 elderly women (average age, 38.4 years) to study the feasibility and necessity of screening trisomy 21 in embryos in patients over 35 years old at the in vitro fertilization (IVF) center.