Application of a data-mining method based on Bayesian networks to lesion-deficit analysis

Although lesion-deficit analysis (LDA) has provided extensive information about structure-function associations in the human brain, LDA has suffered from the difficulties inherent to the analysis of spatial data, i.e., there are many more variables than subjects, and data may be difficult to model using standard distributions, such as the normal distribution. We herein describe a Bayesian method for LDA; this method is based on data-mining techniques that employ Bayesian networks to represent structure-function associations. These methods are computationally tractable, and can represent complex, nonlinear structure-function associations. When applied to the evaluation of data obtained from a study of the psychiatric sequelae of traumatic brain injury in children, this method generates a Bayesian network that demonstrates complex, nonlinear associations among lesions in the left caudate, right globus pallidus, right side of the corpus callosum, right caudate, and left thalamus, and subsequent development of attention-deficit hyperactivity disorder, confirming and extending our previous statistical analysis of these data. Furthermore, analysis of simulated data indicates that methods based on Bayesian networks may be more sensitive and specific for detecting associations among categorical variables than methods based on chi-square and Fisher exact statistics.     

Impact of a nursing information system on practice patterns in Taiwan

The purpose of this study was to measure changes in nursing practice patterns between the beginning stage and a later phase of implementing the nursing information systems. The study was a two-stage data comparison analysis. The data were collected during the first 2 weeks and 1 year after installing the nursing information system. Nursing activities were checked from a list with 83 items. Data were collected by a work sampling strategy during two 2-week periods in November 2004 and November 2005. For both stages, nurses spent about 20% of their time on direct care, 25% on indirect care, 9% on unit-related activities, 30% on documentation, and 15% on personal time. After 1 year of using the nursing information system, nurses spent more time on documentation but less on indirect care and unit-related activities. When unit patient census was high, nurses spent more time on direct care. Issues regarding evaluating the impact of information systems on practice patterns were explored.     

A microarray to analyze methylation patterns of p16(Ink4a) gene 5'-CpG islands

OBJECTIVES: Aberrant DNA methylation of the CpG site is among the earliest and most frequent alterations in cancer. Several studies suggest that aberrant methylation on the CpG sites of the tumor suppressor gene is closely associated with carcinogenesis. However, large-scale analysis of candidate genes has so far been hampered by the lack of high throughput approach for analyzing methylation patterns. The aim of this study was to develop a new method to analyze methylation patterns of p16(Ink4a) gene. DESIGN AND METHODS: We selected a 336 bp segment of the 5' untranslated region and the first exon of the p16(Ink4a) gene, as the target sequence, which include the most densely packed CpG fragment of the islands containing 32 CpG sites. A set of oligonucleotide probes was designed to assemble a DNA microarray to discriminate the methylation patterns of several adjacent CpG sites. RESULTS: Methylation patterns of human p16(Ink4a) gene were mapped and the results were validated by bisulphite DNA sequencing. A good reproducibility was observed in several parallel experiments. CONCLUSIONS: The methylation oligonucleotide microarray can be applied as a useful and powerful tool to map methylation patterns in multiple CpG island sites.     

挤切劈核法在硬核白内障超声乳化术中的应用

目的探讨挤切劈核法在硬核白内障超声乳化术中的应用。方法对IV级以上的硬核白内障100例(108眼)实施挤切劈核技术,即在核中心将乳化针头嵌入核内深达3/4核厚度,能量50%,负压250mmHg,停止乳化利用负压吸引的作用固定晶状体核,用劈核器Chopper绕经核的6点钟位赤道部进入核下,利用侧刃与乳化头相对应,二者用力使用挤和切的方式将核碎成2块,旋转晶状体,最终碎成6～8块,并逐一乳化吸除。平均超声乳化时间1.2分钟。结果术后3天视力≥0.5者62眼(57.41%);术后1周视力≥0.5者98眼(90.74%),主要并发症为后囊破裂7眼,角膜水肿5眼。结论硬核白内障超声乳化术中挤切劈核法操作简便、安全,术后效果好。     

分选高纯度肾小球内皮细胞基础上应用小干扰RNA技术分析5-脂氧合酶激活蛋白的作用

目的:采用多个内皮细胞特异性表达或吸收的蛋白分选高纯度的肾小球内皮细胞,观察5-脂氧合酶激活蛋白在细胞因子诱导的肾小球内皮细胞蛋白通透性中的可能作用.方法:实验于2005-12/2007-03在卫生部北京老年医学研究所完成.①实验材料:雌性Wistar大鼠2只,100～120 g.②实验过程:用胶原酶消化大鼠肾小球细胞,先后用抗CD31和抗acetylated-LDL抗体标记细胞,通过流式细胞仪纯化肾小球内皮细胞,用抗CD54、CD106和CD62E鉴定分离的细胞.③评估:通过小干扰RNA技术抑制肾小球血管内皮细胞表达5-脂氧合酶;用干扰素-γ刺激细胞,通过免疫印迹杂交和免疫荧光组织化学检测5-脂氧合酶蛋白的表达;用FITC标记的BSA作为指示剂来测量体外培养的肾小球血管内皮细胞的蛋白通透性.结果:①分选高纯度肾小球内皮细胞:CD31磁珠分选得到83.3% CD31阳性细胞,其中12.5%为同时CD31 和高吸收acetylated-LDL.分离该双阳性细胞后得到纯度大于99.2%的肾小球内皮细胞.流式细胞仪检测显示这些细胞的CD54、CD106和CD6也均为阳性.在相差显微镜下观察,细胞形态呈鹅卵石状.②细胞膜上5-脂氧合酶定位:用干扰素-γ处理细胞后,5-脂氧合酶蛋白表达水平升高并呈时间和剂量依赖性.③细胞转染5-脂氧合酶小干扰RNA后结果:用干扰素-γ处理,干扰素-γ不能诱导5-脂氧合酶的高表达;用干扰素-γ处理细胞后转染5-脂氧合酶小干扰RNA,干扰素-γ诱导5-脂氧合酶蛋白表达水平被明显抑制.④在5-脂氧合酶小干扰RNA转染细胞中干扰素-γ处理和未处理细胞白蛋白的通透率:分别为(0.37±0.09)% 和(0.31±0.06)%,差异没有显著性(P＞0.05).结论:干扰素-γ能够诱导肾小球内皮细胞表达5-脂氧合酶蛋白并导致细胞通透性增高.5-脂氧合酶蛋白介导了干扰素-γ诱导细胞通透性增高的过程.