高危妊娠与胎母输血的相关性分析

目的探讨孕晚期母亲血胎儿红细胞量（KB）与新生儿血红蛋白的相关性。方法运用用红细胞酸洗脱染色试验,监测297例入院待产孕妇的KB值,比较正常孕妇和高危孕妇KB的差异性,并观察其与新生儿出生后24 h内测的血红蛋白值的相关性。结果297例孕妇血中（正常妊娠162例,高危妊娠135例）,234例可测到胎儿红细胞,KB值为0.01%～5.2%,胎儿红细胞检出率占监测人数的78.79%。经非参检验表明,高危妊娠组的KB值明显高于正常组,差异有极显著意义（〈0.001）;母亲KB值与新生儿血色素值的相关性不强,但对母亲KB值进行分层观察发现,以KB≥0.4%为界值,≥0.4%与〈0.4%组间的新生儿Hb值存在差异显著性（=10.406,〈0.01）,KB≥0.4%组新生儿的Hb水平较低。结论大部分高危妊娠孕妇存在胎母输血现象。孕期KB值监测对胎母输血高危孕妇以及高危新生儿的筛选有一定价值。     

Modelling the monetary value of a QALY: a new approach based on UK data

Debate about the monetary value of a quality-adjusted life year (QALY) has existed in the health economics literature for some time. More recently, concern about such a value has arisen in UK health policy. This paper reports on an attempt to 'model' a willingness-to-pay-based value of a QALY from the existing value of preventing a statistical fatality (VPF) currently used in UK public sector decision making. Two methods of deriving the value of a QALY from the existing UK VPF are outlined: one conventional and one new. The advantages and disadvantages of each of the approaches are discussed as well as the implications of the results for policy and health economic evaluation methodology.     

Globally optimal trial design for local decision making

Value of information methods allows decision makers to identify efficient trial design following a principle of maximizing the expected value to decision makers of information from potential trial designs relative to their expected cost. However, in health technology assessment (HTA) the restrictive assumption has been made that, prospectively, there is only expected value of sample information from research commissioned within jurisdiction. This paper extends the framework for optimal trial design and decision making within jurisdiction to allow for optimal trial design across jurisdictions. This is illustrated in identifying an optimal trial design for decision making across the US, the UK and Australia for early versus late external cephalic version for pregnant women presenting in the breech position. The expected net gain from locally optimal trial designs of US$0.72M is shown to increase to US$1.14M with a globally optimal trial design. In general, the proposed method of globally optimal trial design improves on optimal trial design within jurisdictions by: (i) reflecting the global value of non-rival information; (ii) allowing optimal allocation of trial sample across jurisdictions; (iii) avoiding market failure associated with free-rider effects, sub-optimal spreading of fixed costs and heterogeneity of trial information with multiple trials.     

Reference values for serum levels of cholesteryl ester transfer protein and its distribution characteristics in healthy Chinese children and newborns

Objective

To investigate the distribution characteristics of serum CETP levels in childhood.

Design and methods

CETP was measured in 912 healthy children and 40 cord blood with an ELISA.

Results

CETP was skewed in children with a median of 2.48 (2.5-97.5 percentiles: 0.56-6.96) mg/L. CETP in cords was much lower than in children, and was lower in younger children (< 1 year) than in elder children.

Conclusions

CETP is lowest at birth and sharply rises to maximum levels in infancy.     

急性胰腺炎中超声的诊断价值

目的：急性胰腺炎中超声对其诊断的准确性及其意义。方法：回顾法分析临床确诊急性胰腺炎病例中超声诊断价值,并与CT进行对照。结果：115例急性胰腺炎,超声诊断符合率89％,CT检出率95％。其中急性水肿型胰腺炎98例,急性坏死性胰腺炎17例。结论：超声与CT对比仍可作为急性胰腺炎的首诊手段,且在某些方面还有其优势。     

不同年龄正常人群视乳头形态结构检测

目的建立正常人视乳头形态结构参数的正常值,探讨性别、眼别、年龄对视盘参数的影响。方法应用海德堡视网膜断层扫描仪（HRT）对300例（600眼）正常人视乳头结构进行扫描,按年龄分成5组,获取视盘参数值并分析性别、眼别、年龄和参数的关系。结果300例（600只眼）视盘面积（DA）为（2.1969±0.4611）mm2,视杯面积（CA）为（0.5262±0.3204）mm2,盘缘面积（RA）为（1.6627±0.3774）mm3,杯盘面积比（C/DR）为0.2307±0.1150,视杯容积（CV）为（0.1209±0.1175）mm3,盘缘体积（RV）为（0.4983±0.1571）mm3,杯的平均深度（MCD）为（0.2286±0.0951）mm,视杯的最大深度（MxCD）为（0.6498±0.2343）mm,沿轮廓线的视网膜表面的高度变化最大值（HVC）为（0.4582±0.1400）mm,视杯三维形状的测量值（CSM）为（-0.1911±0.0697）mm,平均视网膜神经纤维层厚度（mRNFLT）为（0.2964±0.0742）mm,平均视网膜神经纤维层截面面积（RNFLA）为（1.5210±0.3875）mm2。300例视盘参数不同眼、不同性别差异无显著性（〉0.05）。44岁以前与44岁以后的各年龄组比较mRNFLT、RNFLA差异有显著性（〈0.05）,而44岁以前的各年龄组比较差异无显著性（〉0.05）。结论正常人视乳头参数值变异较大,随年龄增加,视网膜神经纤维层逐渐变薄,年龄越大退变越明显。视盘参数不同眼、不同性别差异无显著性。     

(18)~F-FDG PET/CT和MRI对鼻咽癌诊断价值的比较

目的： 比较18F-FDG PET/CT和MRI在鼻咽癌TNM分期中的诊断价值,阐明18F-FDG PET/CT 标准化摄取值（SUV）与鼻咽癌T分期和病理类型的关系。方法：41例鼻咽癌患者行18F-FDG PET/CT全身扫描,且于3周内行头颈部MRI检查。按照国际通用的美国癌症联合委员会(AJCC)鼻咽癌TNM分期标准对病变分别行MRI、PET/CT分期,并将组织病理结果作为参照标准。结果：①原发肿瘤：PET/CT诊断鼻咽癌T分期的准确率为85.37%,MRI的准确率为60.98%,两者比较差异有显著性（U=2.49,P< 0.05）;结合病理结果提示,PET/CT降低分期3例,提高分期7例;鼻咽癌患者原发灶SUV值与鼻咽癌T分期呈明显正相关关系（rs=0.706,P<0.05）。未分化癌患者SUV值明显高于低分化鳞癌,两组间比较差异有显著性（t=7.89,P<0.05）。②淋巴结转移：41例患者共切取淋巴结139枚,其中PET/CT正确判断阳性72枚,阴性56枚,灵敏度和特异度分别为93.51%和90.32%;MRI正确判断阳性60枚,阴性51枚,灵敏度和特异度分别为80.00%和79.69%;PET/CT诊断淋巴结转移的准确率为92.09%,MRI诊断淋巴结转移的准确率为79.86%,两者比较差异有显著性（U=2.93,P< 0. 05）。③远处转移：41例患者18F-FDG PET/CT全身扫描结果中,2例患者出现肝脏和骨骼远处转移灶,而MRI因扫描部位的限制未能显示。结论：18F-FDG PET/CT对鼻咽癌的TNM分期较MRI更全面、可靠。     

Economic valuation of informal care in Asia: A case study of care for disabled stroke survivors in Thailand

This study values informal care for disabled stroke survivors in Thailand. It applies the conventional recommended opportunity cost method to value informal care in monetary terms. Data were collected by means of face-to-face interviews conducted during 2006. The sample consisted of 101 disabled persons who had suffered a stroke at least six months prior to the interview, and who had a functional status score of less than 95 as measured by the Barthel Index. Average monthly time spent on informal care was 94.6 hours, and the major source of opportunity cost was forgone unpaid work (43.5%). The average monthly monetary value of informal care was 4642.6 baht, based on 2006 prices. This study shows that providing informal care involves a substantial opportunity cost, implying a hidden value to Thai society.     

A computationally efficient hypothesis testing method for epistasis analysis using multifactor dimensionality reduction

Multifactor dimensionality reduction (MDR) was developed as a nonparametric and model‐free data mining method for detecting, characterizing, and interpreting epistasis in the absence of significant main effects in genetic and epidemiologic studies of complex traits such as disease susceptibility. The goal of MDR is to change the representation of the data using a constructive induction algorithm to make nonadditive interactions easier to detect using any classification method such as naïve Bayes or logistic regression. Traditionally, MDR constructed variables have been evaluated with a naïve Bayes classifier that is combined with 10‐fold cross validation to obtain an estimate of predictive accuracy or generalizability of epistasis models. Traditionally, we have used permutation testing to statistically evaluate the significance of models obtained through MDR. The advantage of permutation testing is that it controls for false positives due to multiple testing. The disadvantage is that permutation testing is computationally expensive. This is an important issue that arises in the context of detecting epistasis on a genome‐wide scale. The goal of the present study was to develop and evaluate several alternatives to large‐scale permutation testing for assessing the statistical significance of MDR models. Using data simulated from 70 different epistasis models, we compared the power and type I error rate of MDR using a 1,000‐fold permutation test with hypothesis testing using an extreme value distribution (EVD). We find that this new hypothesis testing method provides a reasonable alternative to the computationally expensive 1,000‐fold permutation test and is 50 times faster. We then demonstrate this new method by applying it to a genetic epidemiology study of bladder cancer susceptibility that was previously analyzed using MDR and assessed using a 1,000‐fold permutation test. Genet. Epidemiol. 2008. © 2008 Wiley‐Liss, Inc.     

A note on permutation tests for genetic association analysis of quantitative traits when variances are heterogeneous

The genetic dissection of quantitative traits, or endophenotypes, usually involves genetic linkage or association analysis in pedigrees and subsequent fine mapping association analysis in the population. The ascertainment procedure for quantitative traits often results in unequal variance of observations. For example, some phenotypes may be clinically measured whilst others are from self‐reports, or phenotypes may be the average of multiple measures but with the number of measurements varying. The resulting heterogeneity of variance poses no real problem for analysis, as long as it is properly modelled and thereby taken into account. However, if statistical significance is determined using an empirical permutation procedure, it is not obvious what the units of sampling are. We investigated a number of permutation approaches in a simulation study of an association analysis between a quantitative trait and a single nucleotide polymorphism. Our simulations were designed such that we knew the true p‐value of the test statistics. A number of permutation methods were compared from the regression of true on empirical p‐values and the precision of the empirical p‐values. We show that the best procedure involves an implicit adjustment of the original data for the effects in the model before permutation, and that other methods, some of which seemed appropriate a priori, are relatively biased. Genet. Epidemiol. 33:710–716, 2009. © 2009 Wiley‐Liss, Inc.