心肌肌凝蛋白诱导BALB/c小鼠发生自身免疫性心肌炎

目的:建立BALB/c小鼠实验性自身免疫性心肌炎模型.方法:采用差速离心、分级饱和硫酸铵沉淀和DEAE-Sephadex A-50离子交换层析纯化等方法自猪心中提取并纯化心肌肌凝蛋白,经SDS-PAGE和Western印迹方法鉴定.以此蛋白免疫遗传易感的BALB/c小鼠,建立自身免疫性心肌炎模型.结果:97％(35/36)小鼠在免疫后第14天出现不同程度的心肌炎病理改变,主要表现为心肌间质单个核细胞浸润、肌纤维排列紊乱和肌浆溶解.免疫鼠血清肌钙蛋白I水平升高,并出现较高滴度的抗肌凝蛋白自身抗体.结论:猪心肌肌凝蛋白可以诱导BALB/c小鼠出现典型的自身免疫性心肌炎.     

1，25二羟维生素D3对实验性变态反应性脑脊髓炎保护作用的研究

目的：观察1，25二羟维生素D3对豚鼠实验性变态反应性脑脊髓炎（EAE）的预防和治疗效果方法：采用粗制碱性髓鞘蛋白（MBP）加福氏完全佐剂皮下注射的方法建立EAE模型。将30只豚鼠随机分成3组：正常对照组、EAE对照组、EAE治疗组，造模前3d正常对照组和EAE对照组每天灌喂0．4ml花生油，EAE治疗组分别在造模前3d开始灌喂含1，25二羟维生素D32．5μg．kg^-1．d^-1的花生油0．4ml，直至整个实验结束。观察豚鼠发病的潜伏期、进展期和神经功能症状；流式细胞仪法测定高峰期外周血T细胞亚群；酶联免疫吸附（ELISA）法测定高峰期外周血细胞因子IFN-γ、IL-4的含量。结果：正常对照组豚鼠未发病，EAE模型组豚鼠神经功能障碍明显。EAE治疗组与对照组相比，潜伏期明显延长，进展期明显缩短，发病高峰期神经功能障碍评分明显降低，死亡率明显降低；EAE对照组CD4^＋、CD8^＋含量比正常组降低，EAE治疗组CD4^＋、CD8^＋含量比EAE对照组高，EAE对照组CD4^＋／CD8^＋比值比正常组高，EAE治疗组CD4^＋／CD8^＋比值比EAE对照组降低；EAE对照组外周血单个核细胞分泌IL-4的能力较正常对照组明显降低，EAE治疗组外周血单个核细胞分泌IL-4的能力较EAE对照组明显增强。EAE对照组外周血单个核细胞分泌IFN-γ的能力较正常对照组明显增强，EAE治疗组外周血单个核细胞分泌IFN-γ的能力较EAE对照组明显减弱，其差异具有显著性。结论：1，25二羟维生素D3对EAE发病豚鼠具有保护作用：能延长EAE发病的潜伏期、缩短EAE发病的进展期、减轻神经功能障碍、降低高峰期死亡率；能提高外周血CD4^＋和CD8^＋含量、降低CD4^＋／CD8^＋比值。具有调节T细胞亚群失衡和纠正CD4^＋／CD8^＋比值倒置的作用；能抑制外周血单个核细胞分泌IFN-γ，促进外周血单个核细胞分泌IL-4，提示其具有抑制Th1细胞的活性、提高Th2细胞的分泌能力，具有调节Th1／Th2失衡的作用。     

腺病毒介导的TGF-β1基因转导对小鼠自身免疫性心肌炎的治疗作用

目的:研究腺病毒介导的TGF-β1基因转导对小鼠自身免疫性心肌炎的治疗作用.方法:以猪心肌肌凝蛋白免疫BALB/c小鼠,诱导自身免疫性心肌炎;实验组以腺病毒为载体转移TGF-β1基因,对照组则转移Lacz基因;采用ELISA法测定血浆TGF-β1浓度,间接ELISA法检测肌凝蛋白自身抗体,荧光酶联免疫法检测肌钙蛋白I;从心肌炎细胞浸润程度、血浆肌钙蛋白I水平、血浆肌凝蛋白自身抗体滴度评估TGF-β1转基因治疗自身免疫性心肌炎的作用.结果:实验组血浆TGF-β1浓度显著高于对照组和正常小鼠(P<0.01),对照组和正常小鼠无显著性差异;实验组小鼠心肌炎细胞浸润程度明显低于对照组,血浆中的肌钙蛋白I水平和抗肌凝蛋白自身抗体水平低于对照组(P<0.01).结论:腺病毒介导的TGF-β1基因转导对小鼠自身免疫性心肌炎有明显的治疗效果.     

T淋巴瘤TCR β链独特型DNA疫苗诱发小鼠体液免疫反应

目的：研究T淋巴瘤TCRβ链独特型DNA疫苗诱发小鼠体液免疫反应。方法：大剂量提取质粒，将BALB／c小鼠随机分为pcNSA3．1组、pcDNA3．1／TCRVβ8组、pcDNA3．1／TCRVβ8＋IL－2组、pcDNA3．1／TCRVβ8＋CpG＋脂质体组和全硫代CpG组共5组（每组6），双侧股四头肌内注射疫苗免疫，于第0、2、4周各免疫1次，共3次。每次免疫前及免疫开始后至第8周，取鼠血，应用间接免疫荧光检测小鼠抗体生成情况。结果：pcDNA3．1／TCRVβ8组、pcDNA3．1／TCRVβ8＋CpG＋脂质体组、pcDNA3．1／TCRVβ＋IL－2组小鼠血清中均产生了特异性抗独特型抗体，抗体滴度在第4周开始增高，第6周时达到高峰。在同一取血时间，pcDNA3．1／TCRβV8＋CpG＋脂质体组和pcDNA3．1／TCRVβ8＋IL－2组小鼠抗体滴度均高于pcDNA3．1／TCRβ8组（P＜0．001。结论：DNA重组质粒pcDN3．1/TCRVβ8可诱导小鼠产生特异性抗体淋巴瘤细胞的独特型抗体；IL－2、CpG和脂质体增强了TCRVβ8基因疫苗诱导的体液免疫反应。     

小鼠慢性自身免疫性心肌炎模型的建立

目的:建立Balb/c小鼠实验性慢性自身免疫性心肌炎模型.方法:用遗传易感的5周龄雄性Balb/c小鼠,于第0天、第7天、第21天、第42天重复皮下注射纯化的猪心肌肌球蛋白,分别于免疫后14、21、42、70 d处死小鼠,观察组织病理变化情况,测定血清肌球蛋白抗体滴度和心肌肌钙蛋白Ⅰ(cTnⅠ)浓度.结果:实验组86%(31/36)小鼠出现不同程度的心肌炎病理改变.14 d、21 d出现急性心肌炎表现,主要为心外膜下、心肌间质单个核细胞浸润和肌浆溶解.42 d、70 d符合慢性心肌炎病理表现,主要表现为肌纤维排列紊乱、纤维化,而心肌间质和心外膜下仍可见少量单个核细胞浸润.血清抗心肌肌球蛋白自身抗体滴度、cTnⅠ浓度在急慢性期不同时间段均有不同程度增高.结论:猪心肌肌球蛋白重复免疫可以诱导Balb/c小鼠出现典型的炎症持续存在的慢性自身免疫性心肌炎.     

孕晚期小鼠巨噬细胞抗原递呈功能对Th1/Th2免疫的影响

目的 探讨孕晚期Balb/c小鼠脾脏巨噬细胞抗原提呈功能与母体Th2＞Th1免疫偏倚的关系.方法 选取孕晚期Balb/c小鼠作为研究对象,以动情期小鼠为对照.将Balb/c小鼠脾脏巨噬细胞经抗原激发后作为抗原递呈细胞(APC),一部分(1°APC)用于致敏小鼠T细胞,然后分离致敏T细胞,再将另一部分巨噬细胞(2°APC)与致敏T细胞混合培养.采用淋巴细胞抗原特异性转化实验检验孕晚期小鼠脾脏巨噬细胞抗原提呈功能的改变,采用流式细胞技术检测CD4、CD8、IL-10和IFN-γ在反应后T细胞上的表达. 结果以孕晚期Balb/c小鼠脾脏巨噬细胞作为1°APC致敏动情期小鼠,再以孕晚期Balb/c小鼠脾脏巨噬细胞作为2°APC体外诱导致敏T细胞增殖的强度与对照组作为2°APC比较,差异无统计学意义(P＞0.05);以动情期Balb/c小鼠脾脏巨噬细胞作为1°APC,再以孕晚期Balb/c小鼠脾脏巨噬细胞作为2°APC诱导致敏T细胞增殖的强度则低于对照组作为2°APC时的增殖强度(P＜0.05).孕晚期小鼠脾脏巨噬细胞作为2°APC可诱导更多IL-10 T细胞产生(P＜0.05);IFN-γ T细胞的比例与1°或2°APC的类型无关. 结论孕晚期Balb/c小鼠脾脏巨噬细胞不是一种有效的APC细胞,可诱导孕期母体的Th2型免疫,并使Th1型免疫维持一定水平,对正常妊娠具有重要意义.     

脾脏CD4^＋T、CDl9^＋B淋巴细胞凋亡在狼疮性BXSB小鼠发病机制中的意义

目的对♀、♂狼疮性BXSB小鼠外周血T、B淋巴细胞分布及脾脏T、B淋巴细胞凋亡进行比较探讨脾脏CD4^＋T、CDl9^＋B淋巴细胞凋亡在狼疮性BXSB小鼠发病机制中的意义。方法运用流式细胞术、免疫双荧光染色法检测外周血CD4^＋T、CD8^＋T、CDl9^＋B细胞分布及脾脏CD4^＋T、CDl9^＋B细胞凋亡;直接免疫荧光法观察♀、♂狼疮性BXSB小鼠肾脏免疫组化。结果与早BXSB小鼠比较,6BXSB小鼠外周血CD4^＋T、CD8^＋T细胞分布明显降低（P〈0．01）,外周血CDl9^＋B细胞分布及脾脏CD4^＋T、CDl9^＋B凋亡率明显升高（P〈0．01）;6BXSB小鼠绝大多数肾小球毛细血管襻上可见大量IgG呈片状沉积,而早BXSB小鼠肾脏几乎无IgG沉积。结论6BXSB小鼠发病较早BXSB小鼠重,细胞凋亡在BXSB小鼠发病机制中具有重要意义。     

黄芪多糖对糖尿病鼠T细胞亚群的免疫调节作用

目的 探讨黄芪多糖（APS）对NOD小鼠T细胞亚群的免疫调节机制。方法 观察APS组和对照组NOD鼠胰岛浸润淋巴细胞免疫组化、脾T淋巴细胞CD4^＋／CD8^＋亚群比值，RT—PCR法检测两组胰岛中IL-1β、IL-2、IL-6、IL-12、TNF—α和INF-γ Th1型细胞因子的mRNA表达。结果 APS可以降低NOD小鼠1型糖尿病的发病率，下降胰岛浸润炎症细胞及脾脏中的CD4^＋／CD8^＋亚群比值。与对照组相比，APS组胰岛IL-1β、IL-2、IL-6、IL-12、TNF-α和INF-1的mRNA表达水平明显下调。结论 APS能纠正NOD小鼠Th1型细胞／细胞因子的免疫失衡状态，预防1型糖尿病的发生。     

应用流式细胞术分析CIK细胞胞内Th1/Th2细胞因子

目的：建立细胞因子诱导的杀伤细胞(cytokine-induced killer,CIK)体外扩增的方法,并从单细胞水平分析CIK细胞的胞内Th1／Th2类因子产生的情况,进一步明确CIK细胞的免疫学特性及其参与的免疫效应机制。方法：取健康人外周血单个核细胞(PBMC),按一定的时间顺序分别加入IFN-γ、IL-2和CD3单抗,体外扩增CIK细胞,再应用流式细胞术,经刺激、阻断、固定、穿透和标记等过程测定CIK细胞内细胞因子IFN-γ和IL-4水平。结果：外周血单个核细胞加细胞因子培养两周后CD3^ CD56^ 增加,培养至第21天、28天未见明显下降;诱导后CD3^ CD8^ 细胞量与CD3^ CD4^ 量相比明显增多;单细胞胞内细胞因子测定显示扩增后的CIK细胞Th1／Th2因子状态明显向Th1偏移。结论：采用多种因子组合刺激外周血单个核细胞,可大量诱导出CD3^ CD56^ 双阳性细胞,具高度增殖性,是一类新型的免疫过继疗法细胞;其偏移的Th1／Th2因子状态可作为解释其极强的细胞毒作用的理论依据。     

T淋巴瘤TCRβ链独特型DNA疫苗在小鼠骨骼肌中的基因蛋白表达

目的：检测T淋巴瘤TCRβ链独特型DNA疫苗的基因表达。方法：大剂量提取质粒，将BALB／c鼠随机分为pcDNA3．1组、pcDNA3．1／TCRVβ8组、pcDNA3．1／TCRβ8＋IL－2组、pcDNA3．1／TCRVβ8＋CpG＋脂质体组和全硫代CpG组共5组（每组6只），双侧股四头肌内注射疫苗免疫，于第0、2、4周各免疫1次，共3次。接种疫苗后5d，用RT－PCR法检测重组质粒mRNA表达。接种疫苗后7d应用免疫组化检测重组质粒蛋白表达。结果：pcDNA3．1／TCRVβ8组、pcDNA3．1／TCRVβ8＋IL－2组、pcDNA3．1／TCRβ8＋CpG＋脂质体组小鼠骨骼肌中均显示mRNA和蛋白表达，而pcDNA3．1组和全硫代CpG组未见mRNA和蛋白表达。结论：T淋巴瘤TCRβ链独特型DNA疫苗在小鼠骨骼肌中有效地表达了基因产物。     

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.