呼吸机相关性肺损伤中胱天蛋白酶1/3介导的细胞凋亡机制及乌司他丁的干预作用

目的探讨呼吸机相关肺损伤中胱天蛋白酶(caspase)1/3介导的细胞凋亡机制及乌司他丁的干预作用。方法将36只大鼠完全随机分为3组:对照组、模型组及乌司他丁组,各12只。对照组大鼠未进行机械通气,模型组和乌司他丁组大鼠给予大潮气量造模,乌司他丁组大鼠在通气前给予静脉预灌注乌司他丁(10万U/kg),模型组大鼠给予等剂量0.9%氯化钠溶液。分析各组大鼠支气管肺泡灌洗液血清生化指标肿瘤坏死因子α(TNF-α)、丙二醛、超氧化物歧化酶(SOD)及谷胱甘肽过氧化物酶(GSH-PX)及细胞凋亡相关因子caspase-1/3、p53、B淋巴细胞瘤基因2/Bcl-2相关X蛋白(BAX/Bcl-2)的表达变化。结果模型组灌洗液TNF-α、丙二醛水平显著高于对照组[(490±51)mg/L比(157±16)mg/L,(62±20)mg/L比(32±11)mg/L,P<0.05],而SOD及GSH-PX水平显著低于对照组[(226±41)k U/L比(401±61)k U/L,(267±33)k U/L比(62.4±52)k U/L,P<0.05],调亡相关蛋白caspase-1/3及p53、BAX显著高于对照组,Bcl-2显著低于对照组。与模型组比较,乌司他丁组上述异常表达蛋白得到部分改善,但仍未恢复到对照组水平(BAX/Bcl-2/p53/caspase-1/3相对光密度=0.25∶0.81∶0.67/1.18∶0.24∶0.61/0.49∶1.28∶0.68/0.38∶0.61∶0.49/0.42∶1.22∶0.74)。结论乌司他丁抑制caspasse-1/3及p53通路改善细胞凋亡引起的呼吸机性肺损伤。     

乌司他丁对呼吸机所致肺损伤大鼠体内炎性因子的影响

目的观察乌司他丁对呼吸机所致肺损伤大鼠体内炎性因子的影响。方法24只SD大鼠随机分为对照组、大潮气量通气组和乌司他丁处理组，每组8只。大潮气量通气组和乌司他丁处理组接受机械通气，通气参数均设为：潮气量30ml／kg，呼吸频率40次／min，吸呼比1：3，吸入氧浓度21％。机械通气4h后分别测定支气管肺泡灌洗液（BALF）中的蛋白含量、白细胞总数以及血清和BALF中肿瘤坏死因子α（TNF-α）、白细胞介素-1β（IL-1β）、IL-6和IL-10的水平。结果大潮气量通气组大鼠BALF中蛋白含量、白细胞总数以及血清和BALF中TNF-α、IL-1β、IL-6水平均显著高于对照组和乌司他丁处理组，但IL-10水平则显著降低。乌司他丁处理组与对照组比较上述指标差异无显著性。结论乌司他丁可以抑制大潮气量机械通气大鼠体内促炎因子的产生，对呼吸机所致的生物伤有预防作用。     

VILI大鼠血清对内皮细胞通透性的影响及其作用机制的研究

目的 研究大潮气量机械通气后大鼠血清炎性介质对内皮细胞骨架及单层细胞通透性的影响及乌司他丁的治疗作用,探讨机械通气生物伤引起肺水肿的细胞和分子机制.方法 将30只SD大鼠分成3组:正常潮气量机械通气组;大潮气量机械通气组;大潮气量机械通气 乌司他丁组.收集机械通气后的3组大鼠的血清,并将这3组血清分别作用于ECV-304细胞,观察聚合型肌动蛋白的变化,并测定血清刺激后的单层内皮细胞通透性的变化.结果 和正常潮气量机械通气相比,大潮气量机械通气大鼠血清中的炎性介质可以导致内皮细胞周边肌动蛋白带消失,细胞中央出现明显应力纤维,细胞骨架重排,而大潮气量机械通气开始时注射乌司他丁的大鼠血清对内皮细胞骨架重排影响减轻,3组机械通气后的大鼠血清作用于单层内皮细胞后,内皮细胞通透系数变化百分比(Pa%)分别为(6.95±1.66)%,(27.50±7.77)%,(17.71±4.66)%.结论 大潮气量机械通气大鼠血清中的炎性介质可诱导内皮细胞骨架中重组,应力纤维形成,增加其通透性,而乌司他丁可减轻大潮气量大鼠血清中炎性介质对内皮细胞骨架的影响,应力纤维生成减少,改善了内皮细胞的通透性.     

乌司他丁对兔百草枯中毒急性肺损伤的保护作用

目的:探讨乌司他丁对兔百草枯中毒急性肺损伤(ALI)的保护作用及其机制。方法:新西兰白兔30只,随机分为对照组,百草枯组和乌司他丁组。百草枯组和乌司他丁组腹腔内注射百草枯,对照组注射等体积无菌生理盐水,乌司他丁组同时给与乌司他丁治疗。3d后测支气管肺泡灌洗液(BALF)中炎症细胞和中性粒细胞弹性蛋白酶(NE)活性和肺叶湿/干重比。结果:百草枯组和乌司他丁组支气管肺泡灌洗液中总细胞数、中性粒细胞数、巨噬细胞数、BALF-NE和肺叶湿/干重比均较对照组增高(P<0.05),乌司他丁组各指标明显低于百草枯组(P<0.05)。结论:蛋白酶抑制剂乌司他丁对兔百草枯中毒急性肺损伤有保护作用。     

乌司他丁对脑缺血再灌注后大鼠海马区神经细胞凋亡及学习记忆功能的影响

目的:研究乌司他丁对大鼠脑缺血再灌注(IR)后海马区神经细胞凋亡及学习记忆功能的影响.方法:线栓法制作大鼠局灶性脑缺血再灌注模型,同时给予乌司他丁治疗,采用TUNEL和水迷宫测试观察海马区细胞凋亡及学习记忆在脑缺血再灌注后的变化规律.结果:脑缺血组大鼠再灌注后6h,海马CA1区即出现少量凋亡阳性细胞;于48～72h达高峰.乌司他丁能够使海马区神经细胞凋亡的高峰明显下调(P<0.01).水迷宫测试结果表明缺血组潜伏期较正常组明显延长,乌司他丁组潜伏期较缺血组明显缩短.结论:乌司他丁能够有效的抑制大鼠脑缺血再灌注后海马区神经细胞凋亡,明显改善学习记忆功能障碍.     

乌司他丁对缺血诱导的大鼠骨髓间充质干细胞凋亡的影响

目的 研究乌司他丁是否能够抑制缺血诱导的大鼠骨髓间充质干细胞(BMSC)凋亡。 方法 采用25只SPF级C57BL/6J雄性大鼠为研究对象,将大鼠随机平均分为正常对照组、缺血模型组、乌司他丁组、乌司他丁+AKT通路抑制剂组、乌司他丁+ERK通路抑制剂组,其中正常对照组不进行任何前处理;缺血模型组仅进行缺血处理;乌司他丁组、乌司他丁+AKT通路抑制剂(LY294002)组、乌司他丁+ERK通路抑制剂(PD98059)组,每组大鼠在缺血处理BMSC前,分别加入乌司他丁、乌司他丁+LY294002、乌司他丁+PD98059预处理1 h,然后在药物作用下再进行缺血处理。乌司他丁浓度为500 U/ml。 结果 培养6 h后,细胞凋亡比例显著高于培养3 h时,其余相邻时间点之间无显著差异。正常对照组凋亡率与缺血模型组凋亡率之间差异具有统计学意义,缺血模型组大鼠caspase-3显著高于正常对照组。乌司他丁+AKT通路抑制剂组与乌司他丁+ERK通路抑制剂组大鼠caspase-3水平均显著高于乌司他丁组,且乌司他丁+AKT通路抑制剂组大鼠caspase-3水平显著低于乌司他丁+ERK通路抑制剂组大鼠(t=3.289,P=0.046)。 结论 培养6 h效率最高,较适宜作为最佳缺血时间。乌司他丁能够有效抑制大鼠BMSC凋亡。乌司他丁通过ERK抑制通路发挥作用更优于AKT通路。      

乌司他丁对异氟烷介导的大鼠海马神经元凋亡的影响

目的探讨乌司他丁预处理对异氟烷介导的大鼠海马神经元线粒体途径凋亡的影响及可能的机制。方法36只SD雄性 大鼠随机分为对照组、异氟烷组和乌司他丁组,每组12只。对照组不给与任何处理,异氟烷组和乌司他丁组采用0.75%异氟烷 急性暴露6 h,而乌司他丁组在采用0.75%异氟烷急性暴露前,先给与50000 U/kg乌司他丁预处理。以TUNEL染色检测细胞凋 亡,JC-1探针检测线粒体膜电位（△ψm）,Western blot检测细胞色素C释放及caspase-3活性,H2DCFDA探针检测细胞内活性氧 （ROS）。结果与对照组比较,异氟烷组海马神经元凋亡显著增加（P<0.05）,而乌司他丁组显著下降（P<0.05）;异氟烷组神经元 线粒体△ψm显著降低（P<0.05）,乌司他丁组显著提高（P<0.05）;异氟烷组海马神经元ROS、细胞色素C释放及caspase-3活性均 显著增加（P<0.05）,而乌司他丁组显著降低（P<0.05）。结论乌司他丁可以抑制异氟烷介导的大鼠海马神经元凋亡,其机制可 能与抑制线粒体途径凋亡有关。     

乌司他丁对机械通气致肺损伤大鼠肺组织CC16表达的影响

目的 通过观察乌司他丁(UTI)对大潮气量机械通气大鼠肺组织Clara细胞分泌蛋白(CC16)表达的影响,探讨CC16在机械通气所致肺损伤(VILI)发病中作用以及UTI对VILI的干预作用.方法 24只雄性Wistar大鼠随机分为对照组、大潮气量组和UTI干预组,观察其肺组织病理学改变,测定肺组织中丙二醛(MDA)和BALF中总蛋白(TP)含量,采用逆转录聚合酶链反应(RT-PCR)法检测肺组织CC16 mRNA的表达,采用免疫组织化学染色法检测肺组织中CC16蛋白表达及Clara细胞计数.结果 与对照组比较,大潮气量肺组织MDA的含量及BALF总蛋白含量明显升高(P<0.01),而肺细支气管上皮细胞CC16mRNA及其蛋白表达水平明显降低(P<0.01);与大潮气量组比较,UTI干预组大鼠肺组织中MDA的含量及BALF总蛋白含量明显降低(P<0.01),而肺细支气管上皮细胞CC16mRNA及其蛋白表达水平明显升高(P<0.01).结论 大潮气量机械通气导致肺组织CC16 mRNA及其蛋白表达水平降低在VILI发病中起重要作用,乌司他丁不但能促进Clara细胞分泌CC16而抑制肺组织炎症反应,还能抑制脂质过氧化物的产生,对VILI有一定保护作用.     

乌司他丁预先给药对大鼠呼吸机相关肺损伤的影响

目的 研究乌司他丁预先给药对大鼠呼吸机相关肺损伤(VILI)的影响及机制.方法 30只雄性SD大鼠随机分为3组:对照组(C组)、大潮气量组(H组)和乌司他丁组(U组),每组10只.H组和U组接受机械通气,参数设置均为:潮气量40 mL/kg,呼吸频率40次/min,呼气末正压(PEEP)为零,吸入氧浓度为21%.机械通气4 h 后放血处死大鼠,取肺组织测定肺湿/干重比(W/D);收集支气管肺泡灌洗液(BALF)并测定其中的蛋白含量、白细胞计数以及血清和BALF中肿瘤坏死因子(TNF-α)、白细胞介素-6(IL-6)、IL-8、IL-10及超氧化物歧化酶(SOD)和丙二醛(MDA)的水平.结果 与C组相比,H组大鼠W/D、BALF中白细胞计数、总蛋白含量以及血清和BALF中TNF-α、IL-6、IL-8、MDA水平均显著增高,但 IL-10和SOD水平则显著降低;与H组相比,U组大鼠W/D、BALF中白细胞计数、总蛋白含量以及血清和BALF中TNF-α、IL-6、IL-8、MDA水平均显著降低,但 IL-10和SOD水平则显著升高.结论 乌司他丁预先给药能减轻大鼠VILI,其机制可能与抑制肺内炎性细胞因子的释放和氧自由基的生成有关.     

乌司他丁对脓毒症大鼠急性肺损伤的保护作用及机制

目的 观察乌司他丁对脓毒症大鼠急性肺损伤的保护作用及具体作用机制。方法 80只大鼠随机分为假手术组、模型组、乌司他丁组、抑制剂组、乌司他丁+抑制剂组,各16只。乌司他丁+抑制剂组腹腔注射乌司他丁20 000 U/kg、solasodine 50 mg/kg;乌司他丁组腹腔注射乌司他丁20 000 U/kg、等量含5%DMSO生理盐水;抑制剂组腹腔注射solasodine 50 mg/kg、等量生理盐水;模型组与假手术组腹腔注射等量生理盐水、含5%DMSO的生理盐水。检测肺组织湿重/干重（wet weight to dry weight,W/D）比值;ELISA法检测肿瘤坏死因子-α(tumor necrosis factor α,TNF-α)、白细胞介素-6(interleukin 6,IL-6)、IL-10;HE染色观察肺组织病理学,评估肺损伤得分;TUNEL染色观察肺组织细胞凋亡;western blot检测磷酯酰肌醇3-激酶（phosphatidylinositol 3-kinase,PI3K）、蛋白激酶B(protein kinase B,Akt)、p-Akt、雷帕霉素靶蛋白（...     

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.