聚ADP核糖聚合酶抑制剂治疗复发性卵巢癌的系统评价

目的 研究聚ADP核糖聚合酶(PARP)抑制剂治疗复发性卵巢癌的疗效和安全性.方法 采用Cochrane系统评价方法,检索Medline、Embase、Central和中国生物医学文献数据库,检索时限为建库至2017年9月,手工检索相关参考文献,纳入PARP抑制剂治疗复发性卵巢癌的随机对照试验(RCT).应用RevMan5.3软件进行Meta分析.结果 纳入5个RCT,试验组患者1 160例,对照组患者679例.PARP抑制剂治疗较安慰剂明显改善无进展生存[HR =0.34,95％CI(0.30,0.40),P＜0.01]和总生存结局[HR=0.73,95％CI(0.55,0.96),P=0.025],增加客观反应率[RR=2.56,95 ％CI(1.17,5.59),P=0.020].与单用化疗相比,PARP抑制剂+化疗明显降低疾病进展风险[HR=0.51,95％CI(0.34,0.77),P=0.001],但总生存结局[HR=1.17,95 ％CI(0.79,1.73),P=0.440]和客观反应率[RR=1.11,95％CI(0.86,1.42),P=0.420]在两组间的差异无统计学意义.PARP抑制剂治疗明显增加严重贫血、疲劳、恶心及呕吐的发生率.结论 现有证据表明PARP抑制剂能改善复发性卵巢癌的无进展生存结局.     

选择性环氧合酶2抑制剂预防结直肠腺瘤的系统评价

目的 系统性评价选择性环氧合酶（COX）-2抑制剂预防结直肠腺瘤的有效性和安全性。方法 检索Medline（1966至2006年）数据库,OVID（1996至2007年）数据库,EMBASE（1980至2007年1月）数据库,Cochrane图书馆（至2007年1月）以及中国生物医学文献数据库（CBM disk,1997至2007年1月）并鉴定随机对照研究（RCT）的质量。按Jadad质量评分进行评定。用RevMan4．2软件进行荟萃分析。结果 6项随机临床实验中共5708例患者满足纳入标准。选择性COX-2抑制剂与安慰剂比较,能显著降低腺瘤检出率（RR：0．70,95％CI：0．55～0．88,P=0．0003）以及晚期腺瘤检出率（RR：0．69,95％CI：0．53～0．89,P=0．005）。两者发生不良反应事件的危险度差异无统计学意义（RR：1．07,95％CI：0．98～1．17,P=0.11）,但并发心血管等严重事件的危险度差异有统计学意义（RR：1．21,95％CI：1．09～1．33,P=0．0002）。结论 选择性COX-2抑制剂可以有效消退结直肠腺瘤性息肉,可用于结直肠肿瘤的化学预防。但因为其潜在的心血管疾病等风险,尚不可作为常规用药。     

幽门螺杆菌感染与结直肠肿瘤的风险：一项系统综述和荟萃分析

全世界约有一半人口感染了幽门螺杆菌, 幽门螺杆菌感染是消化性溃疡和胃癌等消化道疾病的危险因素。据报道, 幽门螺杆菌也与胃癌以外的恶性肿瘤有关, 如结直肠肿瘤等。为评估幽门螺杆菌感染与结直肠肿瘤之间的关系, 研究者对相关文献进行了系统综述和荟萃分析。通过检索Medline、Embase和Cochrane Library数据库中截至2019年9月发表的关于结直肠腺瘤、进展期结直肠腺瘤、结直肠癌和幽门螺杆菌感染的风险研究, 进行荟萃分析。最终48项研究纳入荟萃分析, 包括171 045例患者, 其中24项、8项和31项分别报告了幽门螺杆菌感染与结直肠腺瘤、进展期结直肠腺瘤和结直肠癌的风险。结果显示, 幽门螺杆菌感染与结直肠腺瘤的风险显著相关(OR=1.49, 95%CI:1.37～1.62);与进展期结直肠腺瘤的风险显著相关(OR=1.50, 95%CI:1.28～1.75);也与结直肠癌的风险显著相关(OR=1.39, 95%CI:1.27～1.52)。尽管这项基于观察性研究的荟萃分析不能显示因果关系, 但它表明, 结直肠腺瘤、进展期结直肠腺瘤和结直肠癌都与幽门螺杆菌感染有关。     

二甲双胍对2型糖尿病患者血清维生素B12水平影响的Meta分析

目的 系统评价二甲双胍对2型糖尿病患者血清维生素B12、叶酸及同型半胱氨酸水平的影响.方法 计算机检索Cochrane Library、EMbase、PubMed、CBM、CNKI、VIP和万方数据库,搜集二甲双胍与2型糖尿病患者血清维生素B12水平相关的随机对照试验(RCT).由2位研究者独立筛选文献、评价纳入研究的偏倚风险、提取数据.采用RevMan5.3软件进行Meta分析.结果 共纳入5个RCT,二甲双胍组血清维生素B12水平较安慰剂组明显降低[MD=-55.86,95％CI(-86.89,-24.84),P=0.000 4];亚组分析显示血清维生素B12水平与糖尿病病程、二甲双胍使用时间及剂量呈负相关;二甲双胍组血清同型半胱氨酸(Hcy)水平较安慰剂组升高[MD=2.44,95％CI(1.41,3.46),P＜0.01];两组血清叶酸水平的差异无统计学意义[MD=-2.39,95％CI(-4.93,o.15),P=0.06];二甲双胍组不良反应发生率高于安慰剂组[RR=2.0,95％CI(1.32,3.03),P=0.001].结论 二甲双胍治疗2型糖尿病患者可引起血清维生素B12水平降低、Hcy水平升高,对叶酸水平无明显影响,患者不良反应发生率较高.     

叶酸摄入与胰腺癌发生风险的meta分析

目的探讨叶酸摄入与胰腺癌发生风险的关系。方法计算机检索Cochrane图书馆、Pubmed、Embase、CBM-disc、CNKI数据库,手工检索相关文献,纳入关于叶酸与胰腺癌发生关系的前瞻性及病例-对照研究。评价质量及提取资料后,采用Stata version 11.0软件对胰腺癌发生风险进行合并。结果共纳入6项队列研究及3项病例-对照研究,2 209例患者。分析提示:从食物中获取叶酸的最高摄入量人群与最低者相比,前组胰腺癌罹患风险统计学上明显降低28%,在以相对危险度(RR)为效应值的队列研究中这种降低趋势更明显[合并RR=0.51,95%CI(0.29,0.89),P=0.017],在病例-对照研究中,合并优势比(OR)=0.79[95%CI(0.66,0.94),P=0.008];总叶酸摄入量(来源于食物及补充的叶酸)最高组人群与最低者相比,胰腺癌罹患风险统计学上明显降低33%,在病例-对照研究中,合并OR=0.53[95%CI(0.30,0.96),P=0.036]。结论本研究结果表明增加总叶酸摄入量(来源于食物及补充的叶酸)及食物来源叶酸摄入量是胰腺的保护因素。     

联合补充维生素C和E预防先兆子发生随机对照试验的meta分析

\[摘要\]目的探讨联合补充维生素C和E是否可以降低妊娠妇女先兆子的发病风险。方法计算机检索电子数据库建库以来至2010年10月关于妊娠妇女联合补充维生素C和E后妊娠结局的随机对照试验研究文献。研究结局为先兆子。采用RevMan 5.0.25软件对各项纳入研究的相对危险度(RR)及其可信区间进行合并,并进行异质性分析。结果共纳入10项研究,19 656例妊娠妇女(实验组9 823例,安慰剂对照组9 833例)。所有纳入研究、纳入的高质量研究、纳入的低质量研究的合并RR值(95%可信区间)分别为0.94 (0.80~1.11, P=0.49),1.02 (0.91~1.14,P=0.79)和0.40 (0.15~1.10,P=0.08)。结论妊娠期间联合补充维生素C和E不能显著降低先兆子的发病风险。     

叶酸对结直肠腺瘤复发干预作用的随访研究

目的探讨叶酸预防结直肠腺瘤复发的作用。方法将104例结直肠息肉切除术后经病理证实为腺瘤者随机分为两组,治疗组46例除一般饮食指导外,给予叶酸口服;对照组58例予一般饮食指导。两组患者每年复查肠镜,随访2年。结果治疗组腺瘤复发率为26.1%(12/46),低于对照组的39.7%(23/58),两组差异无统计学意义(P>0.05);其中治疗组低叶酸水平者复发率为10.3%(3/29),低于对照组的47.2%(17/36),两组差异有统计学意义(P<0.05);治疗组高叶酸水平者复发率为52.9%(9/17),高于对照组的27.3%(6/22),两组差异无统计学意义(P>0.05)。结论补充叶酸可降低低叶酸水平结直肠腺瘤患者腺瘤复发风险,但对高叶酸水平结直肠腺瘤患者无干预作用,尚需进一步扩大样本量验证。     

Empagliflozin治疗2型糖尿病达到HbA1c＜7.0％的有效性及安全性评价

目的 系统评价钠葡萄糖协同转运蛋白2 (SGLT2)抑制剂empagliflozin治疗2型糖尿病(T2DM)达到HbA1c＜7.0％的有效性与安全性.方法 计算机检索Pubmed、Cochrane Library、EMbase,CBM和CNKI数据库发表empagliflozin的文献,检索时限均为建库至2015年10月,筛选合格随机对照试验(RCT).根据Cochrane系统评价手册5.1评估纳入研究偏倚风险,采用RevMan 5.3软件进行统计分析.结果 纳入8篇RCT,共4 728例研究对象.结果显示:empagliflozin使HbA1c＜7.0％的达标率高于安慰剂(10 mg RR=2.68,95％CI:2.06～3.47,P＜0.05;25 mg RR=3.25,95％CI:2.49～4.25,P＜0.05),且不增加低血糖风险(10 mg RR=1.04,95％CI:0.89～1.21,P＞0.05;25 mg RR=1.06,95％CI:0.91～1.23,P＞0.05),同时能降低体质量(10 mg WMD=-1.75,95％CI:—1.96～—1.55,P＜0.05;25 mg WMD=—1.95,95％CI:—2.16～—1.74,P＜0.05),收缩压和舒张压及改善空腹血糖;但增加了生殖道感染风险,在发生泌尿道感染和严重不良事件方面差异无统计学意义,且对T2DM患者肾功能无影响及不增加全因死亡率.结论 Empagliflozin能够有效地使T2DM患者达到HbA1c＜7.0％,另有减轻体质量和降压的临床获益,且安全性好.     

结直肠肿瘤择期手术后应用鼻胃管胃肠减压有效性与安全性的meta分析

目的 探讨结直肠肿瘤择期手术后应用鼻胃管胃肠减压的有效性和安全性.方法 全面检索国内外公开发表的评价结直肠肿瘤择期手术后鼻胃管胃肠减压的随机对照试验(RCTs)文献,根据标准纳入文献,提取临床指标,进行meta 分析.结果 最终纳入6项RCTs(736例),大部分试验的病例组特征上具有可比性.非鼻胃管胃肠减压(non-NGD)组较鼻胃管胃肠减压(NGD)组胃肠功能恢复时间短[加权均数差WMD=-1.15,95％CI(-1.87～-0.43),P=0.002],住院时间少[WMD=-2.43,95％CI(-3.75～-1.10),P=0.000 3],虽呕吐发生多[RR=2.12,95％CI(1.19～3.78),P=0.01],但肺部感染发生少[RR=0.17,95 ％CI(0.03～0.95),P=0.04].两组发生伤口感染[RR=0.76,95％CI(0.29～1.99),P=0.58]和鼻胃管再置[RR=1.85,95％CI(0.89～3.88),P=0.10]差异无统计学意义.结论 结直肠肿瘤手术后不应用鼻胃管是安全的,常规应用鼻胃管并不能给患者带来更多益处,反而会增加并发症(如肺部感染)的发生.     

干扰素β对继发进展型多发性硬化的疗效及安全性评价

目的评价干扰素β与安慰剂对照治疗继发进展性多发性硬化（SPMS）的有效性及安全性。方法采用Cochrane系统评价的方法，计算机检索Cochrane图书馆、MEDLINE、EMbase、CBMdisc及CNKI有关于扰素β与安慰剂对照治疗SPMS随机对照试验，手工补充检索与该病治疗有关的中文期刊文献，按方法学质量评价标准对纳入文献进行评价，使用Cochrane协作网提供的RevMan4．2．10软件进行统计分析。结果纳入干扰素口与安慰剂对照治疗SPMS的随机对照试验5个，共计患者2552例，根据随机分配、分配方案隐藏及盲法三项指标进行质量评分，A级2个，B级3个。Meta分析显示，干扰素β治疗组复发RR=0．84，95％CI为（0．76，0．92），P=0．003；持续进展RR值为0．86，95％CI为（0．76，0．98），P=0．02，RR值均较安慰剂治疗低。干扰素β治疗组注射部位感染发生的RR值为0．64，95％CI为（6．99，16．19），P〈0．0001；注射部位坏死RR值为35．99，95％CI为（4．95，261．50），P：0．0004；发热RR值为2．91，95％CI为（2．20，3．85），P〈0．0001；抑郁RR值为1．24，95％CI为（1．02，1．51），P=0．03；高血压RR值为3．64，95％CI为（1．35，16．01），P=0．02；白细胞减少RR值为2．87，95％CI为（1．34，6．14），P=0．007；头痛RR值为2．22，95％CI为（1．38，3．57），P=0．0009；淋巴细胞减少RR值为1．35，95％CI为（1．10，1．66），P=0．0006；发生转氨酶升高RR值为4．52，95％CI为（1．91，10．72），P=0．0006。干扰素β治疗组不良事件RR值均较安慰剂高（P〈0．05）。结论干扰素β治疗使SPMS复发率及持续进展的发生率降低，不良事件以干扰素β治疗组更为常见。     

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.