目的:探讨应用短串联重复序列(Short tandem repeat,STR)进行Down's综合征诊断的可行性,同时对Down's综合征患儿双亲进行分析,找寻该病的遗传规律。方法:选择21号染色体上D21S1l和D21S1414 2个STR基因座,应用聚合酶链式反应(Pol...目的:探讨应用短串联重复序列(Short tandem repeat,STR)进行Down's综合征诊断的可行性,同时对Down's综合征患儿双亲进行分析,找寻该病的遗传规律。方法:选择21号染色体上D21S1l和D21S1414 2个STR基因座,应用聚合酶链式反应(Polymerase chain reaction,PCR)、变性聚丙烯酰胺凝胶电泳(8%)、硝酸银染色技术分别对100例Down's综合征患儿及20例患儿父母的基因组进行分析。结果:(1)正常人在1个STR基因座上的基因型有2种情况:①2个不同等位基因构成的杂合子,凝胶电泳上表现为粗细一样的2条带。②2个相同等位基因构成的纯合子,凝胶上是2条相同等位基因条带的重叠,其宽度和浓度约为单个等位基因条带的2倍。(2)Down's综合征患儿的等位基因数目和(或)条带浓度有3种特征性改变:①3个不同的等位基因,电泳图上为浓度相同的3条带。②3个等位基因中的2个相同,电泳图上为2条带,其中1条的浓度足另外1条的2倍。③3个相同的等位基因,电泳图上为1条带,这条带的浓度和宽度约为正常对照条带的3倍。(3)20例Down's综合征双亲分析显示,Down's综合征患儿电泳条带包含了母亲的全部电泳条带,而与父亲的电泳条带只有部分相同。结论:(1)利用21号染色体STR位点作为遗传标记,采用PCR扩增技术结合变性聚丙烯酰胺凝胶电泳及硝酸银染色技术,可用于诊断和筛查Down's综合征。(2)Down's综合征患儿与双亲比对电泳结果表明,Down's综合征发病与父母的核型无关,多余的1条21号染色体一般来自于母亲。展开更多
Objective:To compare the efficiency and related financial parameters of the double- and triple-marker test for the second-trimester maternal serum screening for Down's syndrome. Methods:The serum samples were coll...Objective:To compare the efficiency and related financial parameters of the double- and triple-marker test for the second-trimester maternal serum screening for Down's syndrome. Methods:The serum samples were collected from the 2^(nd) trimester pregnant women in this hospital and were examined for three biomedical markers[alpha-fetoprotein(AFP),freeβ-human chorionic gonadotropin(freeβ-hCG) and unconjugated estriol(uE_3)]by TR-FIA.The pregnancy outcomes were followed up and screening efficiency calculated for double-marker(AFP+freeβ-hCG) and triple-marker(AFP+ freeβ-hCG+uE_3) test. Results:(1)A total of 4,707 serum samples of 2^(nd) trimester pregnancy were collected in this study,of which 4,245 pregnancy outcomes got followed up by May 30,2009,with 462 cases lost to follow-up.The follow-up rate was 90.2%.3 cases of Down's syndrome,4 cases of other chromosome abnormalities and 1 case of neural tube defect (NTD) were found.There was no medically induced miscarriage by invasive tests.(2) Detection rate and false positive rate of triple marker test for Down's syndrome screening were 66.7%and 5.26%,respectively,while those in double marker test were 33.3%and 4.01%,respectively.The detection rate of all chromosome abnormalities was 75%in triple marker test and 37.5%in double marker test.The detection rate of NTD was 100%either in double or triple marker test.(3) It costs 499,375 RMB to avoid one Down's syndrome birth by using triple marker test and 781,200 RMB by using double marker test. Conclusion:Triple-marker test is superior to double marker test in 2nd trimester maternal serum screening for Down's syndrome,and costs less to avoid a Down's syndrome birth.展开更多
This work first describes a simple approach for the untargeted profiling of volatile compounds for distinguishing between white duck down (WDD) and white goose down (WGD) based on resolution-optimized GC-IMS combined ...This work first describes a simple approach for the untargeted profiling of volatile compounds for distinguishing between white duck down (WDD) and white goose down (WGD) based on resolution-optimized GC-IMS combined with optimized chemometric techniques, namely PCA. The detection method for down samples was established by using GC-IMS. Meanwhile, the reason of unpleasant odors caused by WDD was explained on the basis of the characteristic volatile compounds identification. GC-IMS fingerprinting can be considered a revolutionary approach for a truly fully automatable, cost-efficient, and in particular highly sensitive method. A total of 22 compounds were successfully separated and identified through GC-IMS method, and the significant differences in volatile compounds were observed in three parts of WDD and WGD samples. The most characteristic volatile compounds of WGD belong to aldehydes, whereas carboxylic acids from WDD were detected generated by autoxidation reaction. Meanwhile, the main reason of unpleasant odor generation was possibly attributed to the high concentration of volatile carboxylic acids of WDD. Therefore, the constructed model presents a simple and efficient method of analysis and serves as a basis for down processing and quality control.展开更多
文摘Objective:To compare the efficiency and related financial parameters of the double- and triple-marker test for the second-trimester maternal serum screening for Down's syndrome. Methods:The serum samples were collected from the 2^(nd) trimester pregnant women in this hospital and were examined for three biomedical markers[alpha-fetoprotein(AFP),freeβ-human chorionic gonadotropin(freeβ-hCG) and unconjugated estriol(uE_3)]by TR-FIA.The pregnancy outcomes were followed up and screening efficiency calculated for double-marker(AFP+freeβ-hCG) and triple-marker(AFP+ freeβ-hCG+uE_3) test. Results:(1)A total of 4,707 serum samples of 2^(nd) trimester pregnancy were collected in this study,of which 4,245 pregnancy outcomes got followed up by May 30,2009,with 462 cases lost to follow-up.The follow-up rate was 90.2%.3 cases of Down's syndrome,4 cases of other chromosome abnormalities and 1 case of neural tube defect (NTD) were found.There was no medically induced miscarriage by invasive tests.(2) Detection rate and false positive rate of triple marker test for Down's syndrome screening were 66.7%and 5.26%,respectively,while those in double marker test were 33.3%and 4.01%,respectively.The detection rate of all chromosome abnormalities was 75%in triple marker test and 37.5%in double marker test.The detection rate of NTD was 100%either in double or triple marker test.(3) It costs 499,375 RMB to avoid one Down's syndrome birth by using triple marker test and 781,200 RMB by using double marker test. Conclusion:Triple-marker test is superior to double marker test in 2nd trimester maternal serum screening for Down's syndrome,and costs less to avoid a Down's syndrome birth.
文摘This work first describes a simple approach for the untargeted profiling of volatile compounds for distinguishing between white duck down (WDD) and white goose down (WGD) based on resolution-optimized GC-IMS combined with optimized chemometric techniques, namely PCA. The detection method for down samples was established by using GC-IMS. Meanwhile, the reason of unpleasant odors caused by WDD was explained on the basis of the characteristic volatile compounds identification. GC-IMS fingerprinting can be considered a revolutionary approach for a truly fully automatable, cost-efficient, and in particular highly sensitive method. A total of 22 compounds were successfully separated and identified through GC-IMS method, and the significant differences in volatile compounds were observed in three parts of WDD and WGD samples. The most characteristic volatile compounds of WGD belong to aldehydes, whereas carboxylic acids from WDD were detected generated by autoxidation reaction. Meanwhile, the main reason of unpleasant odor generation was possibly attributed to the high concentration of volatile carboxylic acids of WDD. Therefore, the constructed model presents a simple and efficient method of analysis and serves as a basis for down processing and quality control.
