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101.
Optimal Selection of Sib Pairs from Random Samples for Linkage Analysis of a QTL Using the EDAC Test
Percentages of extremely concordant and extremely discordant sib pairs are calculated that maximize the power to detect a quantitative trait locus (QTL) under a variety of circumstances using the EDAC test. We assume a large fixed number of randomly sampled sib pairs, such as one would hope to find in the large twin registries, and limited resources to genotype a certain number of selected sib pairs. Our aim is to investigate whether optimal selection can be achieved when prior knowledge concerning the QTL gene action, QTL allele frequency, QTL effect size, and background (residual) sib correlation is limited or absent. To this end we calculate the best selection percentages for a large number of models, which differ in QTL gene action allele frequency, background correlation, and QTL effect size. By averaging these percentages over gene action, over allele frequency, over gene action, and over allele frequencies, we arrive at general recommendations concerning selection percentages. The soundness of these recommendations is subsequently in a number of test cases. 相似文献
102.
Gail Pairitz Jarvik Terri H. Beaty Paul R. Gallagher Paul M. Coates Jean A. Cortner 《Genetic epidemiology》1993,10(4):257-270
A sample enriched for familial combined hyperlipidemia (FCHL) was examined for evidence of an association between genotype at an apolipoprotein B (apoB) elevating locus defined by complex segregation analysis and FCHL. Complex segregation analysis detected a locus with a large effect on plasma apoB levels and was used to compute the most probable genotype of family members. None of the 35 normolipidemic adults carried a copy of the allele associated with elevated apoB levels, yet 58% of the 109 adults with FCHL carried 1 (29%) or 2 (28%) copies. Two of 28 (7%) normal children had 1 copy of this allele and none had 2 copies, while 88 of 182 (48%) children with FCHL had 1 (26%) or 2 (22%) copies. Further, 4l of 48 (85%) individuals classified as having hyperapobetalipoproteinemia did not carry a copy of this “elevated apoB” allele. Therefore, the presence of the allele associated with elevation of apoB level is highly predictive of FCHL and this association cannot be explained solely by the presence of elevated apoB levels in FCHL, suggesting that the locus controlling apoB levels may play an etiologic role in FCHL. © 1993 Wiley-Liss, Inc. 相似文献
103.
A study of the value of electrophoretic and other techniques for typing Acinetobacter calcoaceticus 总被引:1,自引:0,他引:1
Forty-four isolates of Acinetobacter calcoaceticus var anitratus collected during hospital outbreaks were studied using polyacrylamide gel electrophoresis (PAGE), plasmid analysis, antibiograms and biochemical tests to determine their degree of similarity. Reproducibility tests were also carried out on the PAGE and biochemical techniques to determine their validity when used to compare bacteria of the same type isolated intermittently. PAGE data was analysed densitometrically and isolates compared using a similarity matrix. All methods were able to subdivide the isolates, but results did not always correlate well between methods. Reproducibility data indicated that careful attention to technique is required when organisms are examined by PAGE sequentially. Results suggest that no single biotyping technique is likely to be adequate and that electrophoretic, biochemical and antibiogram data may complement one another and other epidemiological data in the typing of these organisms. 相似文献
104.
Summary In this study, the99mTc-MIBI myocardial bullseye display of 31 healthy persons and 34 patients with myocardial ischemia and 17 patients with myocardial
infarction were analyzed quantitatively, and compared with the results of myocardial tomography analysis and qualitative bullseye
analysis. The sensitivities of the three methods were 88.2%, 91.2% and 94.1% respectively (P>0.05), and the specificities were 93.5%, 83, 9% and 83.9% respectively (P<0.05). On the other hand, the quantitative analysis obviously outperformed the other two methods in the detection of ischemic
segments of myocardhum near infarction zone (P<0.01). The quantitative analysis of99mTc-MLBI myocardial bullseye (quantitative bullseye) was an objective, specific and sensitive method for diagnosis of coronary
artery disease. 相似文献
105.
Twenty-four patients treated with 150 mg amitriptyline per day for an episode of major depression underwent a standardized heart rate analysis (HRA) before therapy and after 14 days. The battery of cardiovascular reflex tests included the determination of the coefficient of variation (CV) while resting and during deep respiration, a spectral analysis of heart rate, the heart rate response to standing, and the Valsalva manoeuvre. The results of the initial HRA did not differ from a group of 24 normal control subjects matched for age and sex. On day 14 of treatment the patients showed significantly reduced values of heart rate variability in all tests (P<0.0001), probably due to the anticholinergic side effects of amitriptyline. Heart rate increased form 78.1 to 93.6 bpm on average (P<0.0001). Abnormal CV at rest was registered in 96% of the patients; during deep respiration 29% showed abnormal CV results. An abnormal spectral analysis was found in 100% of the cases (low frequency peak: 42%, mid-frequency peak: 100%, high frequency peak: 79%). The heart rate response to standing was abnormal in 75% and the Valsalva test in 33% of the cases. Eighty-eight percent of the patients fulfilled the criteria of a cardiovascular autonomic neuropathy under the conditions of amitriptyline therapy. As yet, the consequences of these changes for the patients have not been sufficiently elucidated. 相似文献
106.
埃塞俄比亚德布拉巴汗市医院眼科门诊病人1436人中查出盲目患者168人,占门诊病人的11.7%。其中双眼盲67人,占门诊病人的4.67%,占盲人的39.88%;单眼盲101人,占门诊病人的7.03%,占盲人的60.12%。通过分析,初步找出了在埃塞的三大致盲病因,即白内障、青光眼和眼外伤。其中白内障具有重要的开盲意义。 相似文献
107.
正常闪光视网膜电图的频域分析 总被引:3,自引:0,他引:3
应用快速傅里叶转换技术对正常视网膜电图进行频域分析,发现其a、b波的优势频及能量集中在5-75Hz;与OPS波的分离点为77HZ,从而提出单纯记录a、b波及OPS波各自的较理想的通频带。 相似文献
108.
109.
根据热分析谱图峰顶的数学特征与Coats-Redfern方程,推得在一定实验条件下,在系列相关反应中,若峰顶温度相接近,则各反应的表观活化能E与指前因子A之间存在着有动力学意义的补偿效应,即lnA=aE+b。并经系列含水硫酸盐脱水反应实验验证。 相似文献
110.
阿拉善黄鼠疫源地动物鼠疫预报的数学模型 总被引:3,自引:0,他引:3
根据我国阿拉善黄鼠鼠疫自然疫源地1981~1993年鼠疫监测资料,采用多元逐步曲线回归分析,建立了预报阿拉善黄鼠鼠疫流行的数学模型,其拟合率为100%,并得出影响鼠疫流行的主要因子为黄鼠密度和巢蚤指数。 相似文献