SD大鼠髁状突颈部骨折对大鼠髁状突软骨细胞增殖与凋亡的影响

目的研究发育期SD大鼠髁状突颈部骨折对下颌髁状突软骨细胞增殖和凋亡活性的影响.方法18只4周龄SD大鼠,分为髁状突骨折组及空白对照组,分别于术后1周、3周、5周时脱颈处死,取骨折组手术侧、非手术侧及空白对照组髁状突软骨,分别采用免疫组织化学染色和TUNEL染色,观察髁状突软骨细胞中增殖细胞核抗原(PCNA)阳性细胞数和凋亡细胞数.结果在各时间点,手术侧、非手术侧的PCNA阳性细胞数存在统计学差异(P<0.01).术后3、5周,空白组与手术侧PCNA阳性细胞数有统计学差异(P<0.01);术后3周,非手术侧大鼠髁突软骨中凋亡细胞数明显增多,手术侧凋亡细胞数随时间推移明显降低;术后1周,手术侧的凋亡细胞数明显多于非手术侧(P<0.01);术后3周,非手术侧的凋亡细胞数明显多于手术侧(P<0.01);术后1、5周,空白组与手术侧凋亡细胞数有显著性差异(P<0.01).结论一侧髁状突颈部骨折导致两侧髁状突所受应力失衡,影响两侧髁状突软骨细胞增殖与凋亡的平衡,进而影响下颌骨及颌面部的发育.     

功能矫形后退大鼠下颌后髁突软骨改建的分子机制

目的：探讨功能矫形后退大鼠下颌后髁突软骨改建的分子调控机制.方法：SD大鼠40只,实验组配戴模拟临床功能矫治器,强制大鼠下颌后退,对照组不戴模拟矫治器,实验后3天、1、2、3周处死大鼠取髁突,HE染色观察组织学变化,免疫组织化学方法结合图像分析检测TGF-β1、TGF-β R1、IGF-1在髁突中的表达及分布.结果：实验组大鼠下颌后退1～2 mm,镜下见颞下颌关节髁突软骨厚度增加,以生发层和过渡层增加明显,细胞数增多,细胞体积增大,核肥大深染.髁突各层软骨细胞均有TGF-β1、TGF-β R1和IGF-1的表达,免疫组织化学阳性染色相对面积和积分灰度的比较显示：在功能矫形后退下颌后,实验组TGF-β1、TGF-β R1和IGF-1的表达较对照组明显增强,其差异具有统计学意义（P＜0.05）.结论：功能矫形后髁突软骨表现为增生改建、分化功能增强,其发生与TGF-β1、TGF-β R1和IGF-1的表达密切相关.     

静压力对髁突软骨细胞形态和IGF-I及其受体表达影响的研究(摘要)

目的 观察体外单层培养的髁突软骨细胞加载机械压力后细胞形态IGF-I及IGF-IR表达在不同时点的变化.通过对IGF-I及IGF-IR表达变化的研究,对IGF-I及IGF-IR在应力介导的髁突软骨增生改建过程中的作用进行初步探讨.通过对加力后细胞面积的观察,进一步明确细胞形态在应力刺激导致的髁突软骨改建过程中的作用机制.方法 选用新生SD大鼠的髁突软骨作为原代培养的组织来源.应用静压力加载装置对第3代细胞加载强度为120g/cm2的持续压力,加力时间1 h.分别于加力后0、6、12、18、24h收集细胞爬片,用免疫组织化学技术检测压力作用后细胞IGF-I及IGF-IR的表达,以彩色病理图像分析仪分析软骨细胞面积和IGF-I及IGF-IR的阳性强度.对照组细胞除不加力外,其它培养条件和检测方法与实验组相同.结果 强度为120g/cm2的持续压力作用1 h,加力停止后0h和6h,体外培养的髁突软骨细胞IGF-I及IGF-IR表达较对照组增强,加力停止后12、18 h和24 h,表达与对照组相比无显著性差异;加力停止后0 h,实验组细胞面积较对照组增大,其后实验组细胞面积与对照组相比无显著性差异.结论 强度为120g/cm2压力持续作用1 h,力解除后6 h内,显示软骨细胞面积增大和IGF-I及IGI;I-IR表达增强;之后,髁突软骨细胞面积和IGF-I及IGF-IR表达逐渐恢复.提示压力促进了髁突软骨细胞合成IGF-I及IGF-IR,表明IGF-I在压力致髁突软骨细胞功能改变中发挥着积极的作用.     

静压力对髁突软骨细胞形态和IGF-I及其受体表达影响的研究

目的 观察体外单层培养的髁突软骨细胞加载机械压力后细胞形态IGF-I及IGF-IR表达在不同时点的变化.通过对IGF-I及IGF-IR表达变化的研究,对IGF-I及IGF-IR在应力介导的髁突软骨增生改建过程中的作用进行初步探讨.通过对加力后细胞面积的观察,进一步明确细胞形态在应力刺激导致的髁突软骨改建过程中的作用机制.方法 选用新生SD大鼠的髁突软骨作为原代培养的组织来源.应用静压力加载装置对第3代细胞加载强度为120g/cm2的持续压力,加力时间1 h.分别于加力后0、6、12、18、24h收集细胞爬片,用免疫组织化学技术检测压力作用后细胞IGF-I及IGF-IR的表达,以彩色病理图像分析仪分析软骨细胞面积和IGF-I及IGF-IR的阳性强度.对照组细胞除不加力外,其它培养条件和检测方法与实验组相同.结果 强度为120g/cm2的持续压力作用1 h,加力停止后0h和6h,体外培养的髁突软骨细胞IGF-I及IGF-IR表达较对照组增强,加力停止后12、18 h和24 h,表达与对照组相比无显著性差异;加力停止后0 h,实验组细胞面积较对照组增大,其后实验组细胞面积与对照组相比无显著性差异.结论 强度为120g/cm2压力持续作用1 h,力解除后6 h内,显示软骨细胞面积增大和IGF-I及IGI;I-IR表达增强;之后,髁突软骨细胞面积和IGF-I及IGF-IR表达逐渐恢复.提示压力促进了髁突软骨细胞合成IGF-I及IGF-IR,表明IGF-I在压力致髁突软骨细胞功能改变中发挥着积极的作用.     

BMP/Smads信号传导通路在兔下颌持续前导后髁突的表达

目的：探讨免下颌持续功能前导后髁突软骨中BMP／Smads信号传导通路表达与髁突改建的关系。方法：60只8周龄的日本大耳白兔，随机分成实验组（n=36）和对照组（n=24），实验组动物每日24h戴用咬合前导矫正器。实验动物分别在第3天、1周、2周、4周、8周及12周时处死并取材，用免疫组化方法观测髁突组织内BMP-2和Smad1／5、4、6的分布和表达，并对其表达进行灰度测定。结果：BMP-2和Smad1／5、4、6主要在髁突软骨过渡层和肥大层软骨细胞中表达，钙化层的软骨细胞和成骨细胞中也可见BMP-2和Smad1／5、4、6的表达。实验组兔髁突软骨BMP-2和Smad1／5、4、6的表达强度在早期高于同期对照组（P〈0．05），与髁突骨组织改建的活跃程度同步。结论：下颌持续前导后，Smad1／5、4、6作为BMP-2的细胞内信号传导分子，与下颌髁突适应性生长改建关系密切。     

实验性单侧前牙反修复体对大鼠髁突软骨中肿瘤坏死因子-α表达的影响

目的:探讨实验性单侧前牙反修复体致大鼠颞下颌关节骨关节病样变过程中髁突软骨肿瘤坏死因子-α(TNF-α)表达变化。方法:60只6周龄SD雌性大鼠随机分为3个实验组和3个对照组,每组10只。在实验组大鼠左侧上、下切牙粘接金属不良修复体,使其呈反关系。分别于2、4、8周后取颞下颌关节,苏木精-伊红染色观察其组织形态学变化,免疫组织化学染色及实时定量PCR检测TNF-α的表达情况。结果:8周实验组髁突软骨时出现典型退行性变。TNF-α主要表达于髁突软骨肥大层,4周实验组TNF-α的蛋白(P<0.01)及基因(P<0.05)表达较对照组显著增多,8周实验组TNF-α的蛋白(P<0.01)及基因(P<0.05)表达较对照组显著减少,而2周实验组与同龄对照组之间无差异(均P>0.05)。结论:TNF-α参与了髁突软骨骨关节病样变的病理性改建活动。     

咬合创伤对大鼠髁突软骨内PCNA表达的影响

目的 本研究以大鼠为实验对象,建立了咬合创伤模型,采用组织学和免疫组织化学染色等方法,观察在咬合咬合创伤以及去除咬合创伤过程中髁突软骨组织形态及软骨中PCNA的表达变化情况,探讨咬合创伤对髁突软骨内细胞的增殖与分化等活动的影响,进一步增加对咬合创伤致髁突软骨改建的认识.方法 选用成年雄性Wlster大鼠14只,分别随机分为4个实验组及1个对照组.咬合创伤组:左侧上颌第一磨牙配戴改良带环,玻璃离子黏固剂黏固,造成咬合面高点,形成该牙与对颌牙尖窝不吻合的咬合接触关系.去除咬合创伤组:在造成咬合创伤2周后,去除改良带环.对照组:不作任何处理,同环境饲养.咬合创伤组中大鼠分别干放入带环后2、4周处死;去除咬合创伤组大鼠于休息2,4周后处死;对照组大鼠干实验结束后期处死.取大鼠双侧颞下颌关节作HE染色,以及PCNA的免疫组织化学染色.结果 1、咬合创伤可以影响雄性大鼠髁突软骨的改建活动,去除咬合创伤可以改善这种变化. 2、咬合创伤组大鼠髁突软骨中PCNA的表达均出现逐渐增高的趋势,咬合创伤2周时高于对照组,但差异不显着(P>0.05),咬合创伤4周时高于对照组(P<0.05),去除咬合创伤后,与咬合创伤组相比PCNA表达,去除创伤2周组无显着变化(P>0.05),去除创伤4周组明显低于创伤2周组(P<0.05),去除创伤4周组明显低干去除创伤2周组(P<0.05),并出现逐渐减少的趋势,与对照组相比,无显著差异,并恢复到对照组水平(P>0.05).结论 本实验结果提示,大鼠咬合创伤后,髁突软骨发生了的适应性改建,髁突软骨增生,软骨细胞增殖,髁突建立新的平衡以维持其正常的生理功能,咬合创伤去除后,髁突软骨增生减弱,软骨细胞增殖不明显, PCNA含量的改变与髁突软骨的增生与改建密切相关,显示髁突有很强的适应与改建能力,为临床的咬合治疗骨关节病提供了组织学参考及理论参考.     

Herbst矫治器前移下颌对成年大鼠髁状突中Ⅲ型胶原表达的影响

目的探讨Herbst功能矫治器引导成年大鼠下颌前伸,对其髁状突组织中Ⅲ型胶原表达水平的影响,进一步明确Herbst矫治器对成年大鼠髁状突组织改建的作用.方法 60只14周龄雄性SD大鼠随机分为实验组和对照组;实验组大鼠全天佩戴自制Herbst矫治器引导下颌前伸,对照组不佩戴矫治器.于时间点3、7、14、21和30 d分别处死各组大鼠,取右侧髁状突组织,使用免疫组化方法检测髁状突中Ⅲ型胶原蛋白的表达情况.结果对照组髁突软骨Ⅲ型胶原表达较低;3 d实验组髁突后部Ⅲ型胶原表达较相应对照组强（P〈0.05）,其余各实验组均明显强于相应对照组（P〈0.01）.实验组Ⅲ型胶原在30 d时表达最强.结论 Herbst矫治器能够诱导成年大鼠髁状突发生适应性改建.     

Caspase-9在髁突软骨及长骨生长板软骨中表达变化的对比

目的 观察Caspase-9在大鼠髁突软骨与长骨生长板软骨发育中的表达变化, 探讨Caspase-9在软骨细胞发育中的意义.方法 建立SD大鼠不同发育阶段 (E15dP30d) 髁突软骨与长骨生长板软骨发育的动物模型, 采用免疫组化检测Casepase-9在2种软骨中的表达变化.结果 大鼠髁突软骨Caspase-9阳性表达强于生长板软骨 (P<0.05) , 且生长板软骨阳性细胞的分布规律与髁突基本一致.胎鼠Caspase-9阳性主要表达于增殖层;出生后主要表达于成软骨层及肥大层.结论 Caspase-9参与了髁突软骨及生长板软骨的生长发育, 由其所介导的细胞凋亡可能在软骨发育中发挥重要作用.且Caspase-9对于髁突软骨和生长板软骨的发育可能存在某些相同或相似的分子机制.     

咬合创伤对大鼠髁突生长发育影响的实验研究

目的 探讨咬合创伤是否会影响髁突的发育.方法 采用4周龄SD大鼠18只, 随机分为2组, 实验组在左侧上颌磨牙粘结直径为1 mm的钢丝, 对照组不做处理, 于1, 3, 5周处死大鼠, 取实验组双侧及对照组左侧髁突做组织切片.组织学观察髁突形态变化, 免疫组化和TUNEL检测髁突形态及软骨细胞增殖和凋亡情况.结果 组织学显示1, 3, 5周实验组双侧关节与对照组无明显差异.免疫组化和TUNEL显示1, 5周时, 实验组创伤侧与非创伤侧及对照组软骨细胞增殖与凋亡差异无统计学意义 (P>0.05) ;3周时, 创伤侧软骨细胞增殖数减少, 与非创伤侧及对照组相比差异有统计学意义 (P<0.05) .创伤侧软骨细胞凋亡数增加, 与非创伤侧及对照组相比差异有统计学意义 (P<0.05) .结论 一侧咬合创伤对同侧髁突从形态上没有明显影响, 但在细胞生长方面有一定影响, 提示一定程度的咬合创伤不足以对生长发育期的髁突产生明显的影响.     

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.