共查询到20条相似文献,搜索用时 31 毫秒
1.
重症肌无力与HLAⅡ类基因关联性在不同人种和民族中具有不同遗传易感性。为探讨中国人重症肌无力(MG)与HLA-DQ分子关联性,采用聚合酶链式反应—限制性片段长度多态性(PCR-RFLP)方法,分析了50例中国正常人及49例重症肌无力患者的HLA-DQA1和-DQB1座位的基因型。结果:共检出正常人DQA1等位基因8种,DQB1等位基因10种,重症肌无力患者DQA1等位基因8种,DQB1等位基因9种。结果分析表明DQA1*0501与MG成负相关,DQB1*0302与MG成正相关。从基因水平首次用PCR-RFLP方法得出中国人重症肌无力DQ分子的易感基因型。 相似文献
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3.
Haemophilia B (Christmas disease) is an inherited, recessive, sex-linked, haemorrhagic condition caused by a defect in the intrinsic clotting factor IX. This disease occurs in males at a frequency of approximately 1 in 30,000. Patients differ in the severity of their clinical symptoms, and variation in the clotting activity and in the concentration of factor IX antigen in their plasma has been demonstrated. There is probably heterogeneity in the molecular defects of the factor IX gene causing the disease. Here we study a severely affected, antigen-negative patient, and show that the only significant sequence difference from the normal factor IX gene is a point mutation changing the obligatory GT to a TT within the donor splice junction of exon f. We infer that this change is the cause of the disease in this individual. In addition, we have used oligodeoxynucleotide probes specific for this mutation to demonstrate the feasibility of carrier detection and prenatal diagnosis for relatives of the patient. 相似文献
4.
探讨了八羧基酞菁铝的分子光谱性质,利用八羧基酞菁铝的荧光光谱(最大激发波长620nm,最大发射波长698nm)近红外特性,建立了一种荧光猝灭法检测Cu2+的新方法。考察了各种因素的影响,实验表明:在优化条件下,(pH 4.5、八羧基酞菁铝浓度5.0×10^-6mol.L^-1、反应时间5min、反应温度为室温)该方法的线性范围2.5×10^-6mol.L^-1~3.0×10^-5mol.L^-1(R=0.9974),检出限8.3×10^-7mol.L^-1.利用该方法测定了实际水样中Cu^2+的含量。 相似文献
5.
本文对U形管换热器管束的固有频率进行了理论分析和实验研究。运用Hamilton变分原理推导了半园弧管振动的微分方程;提出了计算U形管固有频率的模型,得到了计算U形管固有频率的理论计算公式。根据不同的边界条件,推导出U形管的频率方程。用数值方法解频率方程,得到了计算各种U形管固有频率的频率参数并与实测值进行了比较,结果表明,理论计算值不必修正就可应用,方法简便,适合于工程计算和预测校核。 相似文献
6.
Bipolar affective disorders linked to DNA markers on chromosome 11 总被引:13,自引:0,他引:13
J A Egeland D S Gerhard D L Pauls J N Sussex K K Kidd C R Allen A M Hostetter D E Housman 《Nature》1987,325(6107):783-787
An analysis of the segregation of restriction fragment length polymorphisms in an Old Order Amish pedigree has made it possible to localize a dominant gene conferring a strong predisposition to manic depressive disease to the tip of the short arm of chromosome 11. 相似文献
7.
Molecular genetic evidence for heterogeneity in manic depression 总被引:7,自引:0,他引:7
S Hodgkinson R Sherrington H Gurling R Marchbanks S Reeders J Mallet M McInnis H Petursson J Brynjolfsson 《Nature》1987,325(6107):805-806
Manic depression is a severe cyclic mental illness that can be unipolar or bipolar and has a lifetime risk of approximately 7 per 1,000 in most populations. Families with multiple cases of manic depression have been described that are compatible with both autosomal dominant and X-linked modes of genetic transmission. Psychoactive antidepressant and stimulant drugs that help to ameliorate depression and mania are thought to act by affecting catecholamine neurotransmitter systems such as adrenaline, noradrenaline and dopamine, amongst others. Mutations affecting the tyrosine hydroxylase (TH) gene, which encodes the rate-limiting enzyme for the synthesis of these three neurotransmitters, might therefore be responsible for causing the manic depressive phenotype. We have studied three Icelandic kindreds amongst whom it appears that a single autosomal dominant disease allele is segregating. In these families there were 44 cases amongst 73 individuals at risk. Genetic linkage studies were carried out using clones encoding tyrosine hydroxylase the variable portion of the Harvey-ras-1 (HRAS1) locus and the variable region of the insulin gene (INS). All three markers are closely linked on chromosome 11 and were used to observe the segregation of restriction fragment length polymorphisms (RFLPs) in the three affected kindreds. We found no evidence for linkage to these markers in any of the three families. In contrast, Gerhard et al. found linkage between manic depression and HRAS1 in a single large Amish kindred. We conclude that there is genetic heterogeneity of linkage in manic depression. Therefore mutations at different loci are responsible for the manic depressive phenotype in the Amish and in Iceland. 相似文献
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Crystal structure of 1, 4, 8, 11, 15, 18, 22, 25-octa-butoxyphthalocyaninato- copper (Ⅱ) (1) was determined by X-ray diffraction methods. The crystal system is mono-clinic, space group is P21/c, Z = 4, a = 1.3741(1) nm, b = 2.6737(1) nm, c = 1.6690(1) nm, β= 101.278(1)°. The steric congestion between the neighbouring butoxyl groups causes the distortion of the ring core of phthalocyanine (Pc) into a saddle shape conformation. In the crystal structure, molecules stack along a axis forming one-dimensional packing structure and there are two molecular overlap types which appear in turn with different distances between molecules, overlap area and angle. 相似文献
9.
刘敏 《中国科学(G辑)》2013,(8):936-940
本文建立厚度为d的晶粒间界相均匀包围边长为D的三维立方体模型.假定晶粒间界相削弱了晶粒间的交换耦合相互作用.研究了晶粒尺寸及分布对纳米永磁材料有效各向异性及矫顽力的影响.结果表明:单个晶粒的平均各向异性随晶粒尺寸D的增大而增大.且材料的有效各向异性Keff和矫顽力Hc均随平均晶粒尺寸的增大而上升,而上升速率逐渐减慢.Keff和Hc随分布系数的增加而下降,且下降速率逐渐减慢.当Pc=0.7,=1.5,K1(0)=0.2Kh,d=2nm时,我们计算的矫顽力与实验数值符合地很好(Pc是无量纲因子,在0到1之间取值.Kh是晶粒内部正常的磁晶各向异性常数,K1(0)和d分别为晶粒间界相的各向异性常数和厚度). 相似文献
10.
Bing-Song Zou 《科学通报(英文版)》2021,(13):1258-1259
Following the observation of three narrow N* pentaquark states with hidden charm,Pc(4312),Pc(4440)and Pc(4457)[1,2],very recently,the LHCb Collaboration reporte... 相似文献
11.
DFR-1、OsMlo-1分别是最近从水稻中克隆的玉米Hml和大麦中Mlo抗病基因同源序列,这两个序列与两个已报道的水稻抗稻瘟病数量性状位点(QTLs)有较好的对应关系,表明它们所在的基因可能参与抗病反应,为了进一步研究水稻DFR-1、OsMlo-1所在基因的功能,在DFR-1、OsMlo-1假定的外显子上设计引物,通过RT-PCR技术,研究在接种白叶枯病(Xanthomanas oryza pv oryzae)菌株PX099以及接种稻瘟病(Magnoparthe grisea)菌株V86013前后,水稻品种IRBB13和水稻品种明恢63中DFR-1、OsMlo-1所在基因的表达.结果表明:在接种白叶枯病菌株PX099的水稻品种IRBBl3中与DFR-1对应的基因是诱导增强的;在接种稻瘟病菌株V86013的水稻品种明恢63中与DFR-1、OsMlo-1对应的基因是诱导增强的,进一步表明DFR-1、OsMlo-1所在的基因可能参与水稻抗病反应。 相似文献
12.
研究了中国汉族自然群体中血管紧张肽原基因(AGT)M235T多态位点在原发性 高血压患者和同龄对照者之间的等位频率分布.观察到AGT基因的M235T位在中国汉族 人群中存在两个等位因子的遗传多态性(M235/235T),其杂合率(heterozygosity)为30%. T235基因在高血压群体中为88.7%,在正常人群的频率为79.0%,两者有显著性差异(x2= 6.264,p<0.02).提示中国人血管紧张肽原基因(AGT)M235T多态位点与原发性高血压之 间有显著关联. 相似文献
13.
王言英 《大连理工大学学报》1986,(4)
本文根据波浪的随船统计资料,研究了波浪要素的长期分布,海浪谱函数和船舶 性能长期预报方法.应用weibull函数拟合波高和周期的长期分布;沿用第12届 ITTC(1969)海浪谱得到我国沿海海域修正的海浪谱,并给出了各种概率意义下的 波高、周期以及相应的谱矩。 相似文献
14.
卟啉—酞菁二元化合物分子内的能量传递 总被引:1,自引:1,他引:0
赵福利 《中山大学学报(自然科学版)》1998,37(3):50-54
研究了新的以哌嗪连接的含卟啉-酞菁双发色团的分子(Pr-Pc)的时间分辨荧光光谱并对所得的结果进行了分析和讨论.在光谱数据的基础上结合分子的结构对非极性溶剂中二元化合物分子内的能量传递过程和机制进行了讨论,并算出发色团的空间相对距离为1.87nm. 相似文献
15.
S J Lu N E Day L Degos V Lepage P C Wang S H Chan M Simons B McKnight D Easton Y Zeng 《Nature》1990,346(6283):470-471
The frequency of nasopharyngeal carcinoma is nearly 100-fold higher in southern Chinese than in most European populations. Earlier studies have suggested that an increased risk of nasopharyngeal carcinoma is associated with specific haplotypes in the HLA region: relative risks slightly over twofold were found for haplotypes A2, Bw46 and the antigen B17. We now report a linkage study based on affected sib pairs which suggests that a gene closely linked to the HLA locus confers a greatly increased risk of nasopharyngeal carcinoma. The maximum likelihood estimate is of a relative risk of approximately 21. The relationship between this suspected disease susceptibility gene (or genes) and known viral and environmental aetiological factors remains to be elucidated. 相似文献
16.
研究维医不同异常体液型维吾尔族冠心病患者血管紧张素转换酶(ACE)基因、内皮型-氧化氦合酶(eNOS)基因、凝血因子Ⅶ(FVⅡ)基因、细胞黏附分子-1(ICAM-1)基因等基因的多态性变化.采用聚合酶链式反应-限制性片段多态性(PCR-RFLP)方法,分别检测不同异常体液型维吾尔族冠心病患者(共92例)及健康对照组(共30例)4种基因型及其等位基因频率.结果显示,冠心病组、不同异常体液型冠心病组与健康对照组相比,ACE基因、FVⅡ基因、ICAM-1基因在基因型及等位基因频率方面均无显著性差异(p>0.05);异常胆液质、异常黑胆质及异常血液质型冠心病组在eNOS基因型和等位基因频率分布两方面与健康对照组比较,均有显著性差异(P<0.05).但在异常黏液质型冠心病组无显著性差异(P>0.05).由此得出结论:ACE基因、FVⅡ基因、ICAM-1基因多态性与不同异常体液型维吾尔族冠心病患者的关系不明显,而eNOS基因多态性与异常胆液质、异常黑胆质、异常血液质型冠心病患者有相关性. 相似文献
17.
青海省湟源县日月藏族乡藏族ABO血型调查分析 总被引:2,自引:0,他引:2
本文对青海省湟源县日月藏族乡的300名藏族人群进行了ABO血型的随机抽样,其中男女各半,试图了解青海这一藏区的ABO血型分布情况和藏族族源.调查结果为:(1)藏族的ABO血型分布为A型占20.67%、B型占22.33%、O型占48.33%、AB型占8.67%|,特征是:O>B>A>AB,基因频率是p=0.1575、q=0.1673、r=0.6752,特征为r>q>p.(2)藏族ABO血型分布的民族指数为0.9991.此次调查青海省湟源县日月藏族乡的藏族人群具有较高的O基因频率,具有典型的南方人群结构特征,说明藏族与南方诸多民族有着族源关系.调查结果基本上与以往的文献资料相符,且符合我国省区血型频数分布规律. 相似文献
18.
研究了野败型杂交稻(Oryza SativaL.)两个籼稻(Indica)组成三对性状的遗传特性及其基因位点间的相互关系。本研究中酯酶同工酶E12A的存在对缺如,芽鞘的紫色对绿色和柱头的紫色对绿色分别是显性。三对性状分别受三个基因位点的三对等位基因控制,表现出典型的孟德尔遗传特征。三个基因位点间存在着明显的连锁关系,其排列顺序是紫色芽鞘基因位点(Pc)-紫色柱头基因点(Ps)-酯酶同工酶基因位点03(Est-3)。 相似文献
19.
用实测出的59组国产石油馏分临界温度和临界压力数据考察了用化学组成与临界性质相关联预测石油馏分临界性质的ERD(Erbar Riazi Daubert)方法,发现其平均相对偏差较小,临界温度的相对偏差为1.27%,临界压力为5.90%.但这种方法的使用范围很窄,可计算数据组数只占44.1%.为保持ERD方法的优点,解决使用范围窄的问题,本文提出了ESC(Erbar Structural Com-position)方法,此方法先用n-d-m法求出石油馏分结构族组成,再求出结构原子团量百分率,可计算出石油馏分的临界温度和临界压力,其计算准确性与ERD法相近。计算出的国产石油馏分临界温度的平均相对偏差为1.19%,临界压力的相对偏差为7.62 %,使用范围大大扩展,计算数据组数提高到94.9%,在实际应用中ESC法可代替ERD法。 相似文献
20.
In vivo binding pattern of a trans-regulator of homoeotic genes in Drosophila melanogaster 总被引:36,自引:0,他引:36
The specification and maintenance of the metameric pattern in Drosophila melanogaster is regulated by complicated gene interactions. The differential expression of the homoeotic genes of the Antennapedia complex (ANT-C) and bithorax complex (BX-C), which determine segmental identities, is partly controlled by cross-regulatory interactions of loci within the two clusters and partly by trans-acting factors located outside the two complexes. One of the trans-regulatory genes, Polycomb (Pc), acts as a repressor of the ANT-C and BX-C. Mutations of Polycomb result in a complete depression of the homoeotic genes, leading to abdominal transformations of all body segments. Polycomb is part of a large class of trans-regulatory genes (Pc-group), estimated to comprise up to 40 loci. We have raised antibodies against the Polycomb protein, and, using an improved immunostaining technique, showed that the Polycomb protein binds to 60 discrete sites along the polytene chromosomes of salivary glands. These sites comprise the ANT-C and the BX-C as well as several locations of Pc-group genes. This is the first clear evidence for a direct interaction of Polycomb with homoeotic loci and other Pc-group genes. 相似文献