精子冷冻环无保护剂玻璃化冷冻方法的初步研究

目的探讨精子冷冻环无保护剂玻璃化冷冻方法的可行性。方法正常精液标本上游处理后,进行常规冷冻和冷冻环无保护剂的玻璃化冷冻,复苏后分别从活力参数及电镜下超微结构等指标比较两种冷冻方法的效果。结果两种方法冷冻后精子存活率、活动率之间差异无显著性(48%∶48%;44.5%∶43.5%,P>0.05),但均较未冷冻的89%和88.5%明显下降(P<0.001)。超微结构亦较未冷冻时发生了一定的改变,但核结构基本保持完整。结论精子冷冻环无保护剂的玻璃化冷冻是一种简单、方便而行之有效的冷冻方法。     

Kindergarten children's representation and understanding of written number symbols

Two samples of kindergarten children's representation and understanding of written number symbols were examined in two time points in one academic year. About 85% of Chinese five year olds (mean = 5 years 10 months) were able to use conventional number symbols to represent the quantity of 30 or larger. At the end of the kindergarten year, 94% of Chinese six year olds (mean = 6 years 4 months) were able to use conventional number symbols to represent the quantity of 100 or larger. Some Chinese six year olds had problems in representing written addition and subtraction tasks. Children's ability to represent written number symbols, ability to represent written addition and subtraction formula and their performance on written addition and subtraction were closely related. The performance of children in a university-affiliated childcare center was better than that of the center serving working-class families in Time 1, but the performance reversed at the end of the kindergarten year.     

Thrombotic occlusion of the common carotid artery (CCA) in acute ischemic stroke treated with intravenous tissue plasminogen activator (TPA)

Although common carotid artery (CCA) occlusions are rare, acute clinical presentations vary from mild to devastating strokes primarily due to tandem occlusions in the intracranial arteries. Three patients with acute CCA occlusions were treated with systemic tissue plasminogen activator (TPA). Blood pressures were kept at the upper limits allowed with TPA therapy with fluid balance and the 'head-down' position. Recanalization occurred in intracranial vessels only. Marked early neurological improvement occurred in two of three patients. CCA occlusions should not be considered contra-indication to systemic thrombolysis.     

Measurement in clinical trials: A neglected issue for statisticians?

Biostatisticians have frequently uncritically accepted the measurements provided by their medical colleagues engaged in clinical research. Such measures often involve considerable loss of information. Particularly, unfortunate is the widespread use of the so‐called ‘responder analysis’, which may involve not only a loss of information through dichotomization, but also extravagant and unjustified causal inference regarding individual treatment effects at the patient level, and, increasingly, the use of the so‐called number needed to treat scale of measurement. Other problems involve inefficient use of baseline measurements, the use of covariates measured after the start of treatment, the interpretation of titrations and composite response measures. Many of these bad practices are becoming enshrined in the regulatory guidance to the pharmaceutical industry. We consider the losses involved in inappropriate measures and suggest that statisticians should pay more attention to this aspect of their work. Copyright © 2009 John Wiley & Sons, Ltd.     

Image processing in digital radiography

Image processing is a critical part of obtaining high-quality digital radiographs. Fortunately, the user of these systems does not need to understand image processing in detail, because the manufacturers provide good starting values. Because radiologists may have different preferences in image appearance, it is helpful to know that many aspects of image appearance can be changed by image processing, and a new preferred setting can be loaded into the computer and saved so that it can become the new standard processing method.Image processing allows one to change the overall optical density of an image and to change its contrast. Spatial frequency processing allows an image to be sharpened, improving its appearance. It also allows noise to be blurred so that it is less visible. Care is necessary to avoid the introduction of artifacts or the hiding of mediastinal tubes.     

胃癌D17S261和D17S799位点二核苷酸重复序列不稳定性的意义

目的研究二核苷酸重复序列不稳定性〔ＤＲＳＩ〕在胃癌发生中的作用及其临床意义．方法采用ＰＣＲ方法检测了Ｄ１７Ｓ２６１和Ｄ１７Ｓ７９９位点二核苷酸重复序列不稳定性．结果胃癌总ＤＲＳＩ发生率为３４％（１７／５０），其中高中分化腺癌ＤＲＳＩ阳性率（６６７％，１０／１５）显著高于低分化癌（１９４％，６／３１，Ｐ＜００１）；肠型胃癌ＤＲＳＩ阳性率（５５６％，１０／１８）显著高于胃型胃癌（２０％，６／３０，Ｐ＜００５），ＤＲＳＩ与胃癌部位、大小、浸润、分期、淋巴结转移无显著相关．结论ＤＲＳＩ在胃癌的发生中可能起重要作用．     

天津市城区成年居民坐高身高指数的调查

目的：探讨成年人坐高身高指数的规律。方法：按中国体育科学会体育研究会规定的方法，测量男性321名，女性324名成人的坐高和身高，每5周岁为一个年龄组，男女各10个年龄组，结果：坐高身高指数均值曲线在男性21－30岁，女性21－35岁年龄组呈递增趋势，提示成年人QD在此年龄组躯干仍存在生长的可能性，在男性56－70岁，女性61－70岁年龄组呈递减趋势，提示成年人在此年龄组脊柱在逐渐缩短，男女两性的指数曲线在30岁左右形成一个交叉点，在此交叉点前女性低于男性，交叉点之后男性低于女性，成人坐高身高指数均值显示男女两性均属躯干均衡型，结论：成年人坐高身高指数具有阶段性递增，递减规律。     

脾脏切除对胸腺和淋巴结免疫功能的影响

报道脾脏切除（脾切）对动物胸腺和淋巴结免疫功能的影响，脾切后３ｗ大鼠胸腺细胞自发增殖及ＣｏｎＡ诱导增殖均无明显变化，ＣｏｎＡ诱导淋巴结细胞增殖脾切组明显高于假手术对照组，脾切后３ｗ再用ＳＲＢＣ免疫，５ｄ后小鼠腹腔淋巴结数量脾切明显高于对照组，用ＱＨＳ法测定淋巴结细胞对ＳＲＢＣ初次抗体产生脾切组则明显低于对照组。     

Analysis of clozapine response and polymorphisms of the dopamine D4 receptor gene (DRD4) in schizophrenic patients

We have examined the hypothesis that a variable number of tandem repeats in the third cytoplasmic loop of the dopamine D4 receptor influences clinical response to clozapine using a sample of 189 schizophrenic patients. Alleles of the 48-bp repeat, which range from two to ten copies in the normal human population, were analysed by the polymerase chain reaction using genomic DNA as template. Association between these alleles and response to clozapine was tested using the difference in pre-and post-treatment GAS scores as a measure of response. We found no statistically significant variation between genotypic groups and response by analysis of variance. We conclude that the variation of the number of 48-bp repeats alone does not determine response to clozapine. Larger studies are underway to determine if there is a more subtle relationship with sequence variation within the repeats or at other polymorphic sites within the gene that may provide evidence for a component of clozapine's action being at D4 receptors. © 1995 Wiley-Liss, Inc.     

Linkage studies and mutation analysis of the PDEB gene in 23 families with Leber congenital amaurosis.

The phenotype in the rd mouse is similar to the clinical presentation of Leber congenital amaurosis (LCA) in humans. Recently a nonsense mutation in the beta subunit of the cGMP phosphodiesterase (Pdeb) gene has been defined as the cause for the rd phenotype in the mouse and has raised the question as to whether mutations in the human PDEB gene might cause LCA. We have previously cloned and characterized the human homologue of the mouse Pdeb gene and have mapped it to chromosome 4p16.3. In this study, a total of 23 LCA families of various ethnic backgrounds have been investigated. Linkage analysis using highly polymorphic (CA)n microsatellites has excluded the PDEB gene as a cause for LCA in 6 families. In the remaining 17 families, we have searched for mutations in the 22 exons of the PDEB gene using single-strand gel electrophoresis (SSGE). Multiple exonic polymorphisms have been determined. However, no DNA changes in the PDEB gene have been identified in our study population which could be causative for the LCA phenotype.