“美容牌”染发剂对雄性小鼠生殖细胞非程序DNA合成的诱导

本文应用雄性小鼠生殖细胞非程序DNA合成(UDS)检测方法研究了“美容牌”染发剂对雄性生殖细胞DNA的损伤作用。发现该染发剂诱发的UDS与药物剂量呈线性正相关。提示此类染发剂对雄性生殖细胞DNA有损伤作用。其遗传毒理效应应引起注意。     

Attention to Color: An Analysis of Selection, Controlled Search, and Motor Activation, Using Event-Related Potentials

In this study the organization of information processing in a selective search task was examined by analyzing event-related potentials. This task consisted of searching for target letters in a relevant (attended) color. The ERPs revealed two different effects of attention: an early occipital negativity (+/- 150 ms) reflecting feature-specific attention, and a later, central N2b component (+/- 240 ms) reflecting covert orienting of attention. A later, prolonged negativity (search-related negativity) (+/- 300 ms), maximal at Cz, was related to controlled search to letters in the attended color. Detection of relevant targets resulted in a parietal P3b component. Depending on stimulus presentation conditions an earlier response to both attended and unattended targets was found: an N2 component (+/- 250 ms). In these same conditions, C'3-C'4 asymmetries (Corrected Motor Asymmetries--CMA) suggested motor activation at +/- 300 ms, in the same time range as search-related negativity. It was argued that N2 and CMA suggest the existence of a preattentive target detection system, operating in parallel with a slower serial attentive system, as reflected by N2b and search negativity.     

Setting out the frame conditions for feasible use of FFPE derived RNA

Introduction

The usage of formalin-fixed paraffin embedded (FFPE) tissue is characterized by its long shelf-life and simple handling. Therefore it is the most commonly available tissue specimen in routine diagnostics and histological studies. Formaldehyde fixation may result in RNA degradation and cross linking with proteins, while storage conditions also affect RNA integrity. The present study was designed to investigate the influence of these factors on RNA analysis.

Malignant tumor of humerus with features of "adamantinoma" and Ewing's sarcoma

This female patient was born in 1935 and died in 1976 with a malignant bone tumor involving the proximal humerus following multiple local recurrences, axillary lymph node metastases, and pulmonary metastases. Histologically, over the course of time, there was an increase in features of an atypical Ewing's sarcoma, at the expense of findings of a typical, extra-cranial so-called adamantinoma. In contrast to another report, our case showed neither epithelial nor endothelial features on fine structural examination, but rather primitive mesenchymal cells, as is described for Ewing's sarcomas.     

工作记忆、执行功能、加工速度与数学障碍儿童推理和心算能力的关系

目的：探讨工作记忆、执行功能、加工速度与数学障碍儿童推理和心算能力的关系。方法：采用智力测验、成就测验、教师提名、学业成绩相结合的综合标准甑选数学障碍儿童，在长沙市三所小学随机选取4-6年级共12个班，从中抽取24名数学障碍儿壹和24名学习正常儿童。对两组儿童进行工作记忆、执行功能、加工速度以及数字推理、图案推理和心算测验。结果：数学障碍组的工作记忆、执行功能及加工速度测验成绩均屁著低于学习正常组（P〈0．001—0．05），数学障碍组数字推理、图案推理和心算成绩也湿著低于正常组；数字推理、图案推理及心算成绩与听觉工作记忆、视觉工作记忆、执行功能和加工速度均有显著相关；逐步回归分析结果显示，进入推理能力回归方程的自变量有听觉工作记忆和视觉工作记忆；进入心算的回归方程的是听觉工作记忆和加工速度。结论：数学障碍儿童存在工作记忆、执行功能和加工速度缺陷；数学障碍儿童的推理能力低于正常学习儿童，主要可由工作记忆能力不足来解释，而心算能力低下则可由听觉工作记忆和加工速度共同解释。     

Separation distress and attachment in surrogate-reared squirrel monkeys.

Surrogate-reared infant squirrel monkeys were exposed to various conditions of separation from their surrogate. Infants showed significant increases in plasma levels of cortisol when they were placed in an unfamiliar environment during the separation period. Changes in behavior, but not cortisol, were observed under conditions in which the surrogate was removed and the infant left in the home cage. These results differ from those previously obtained with mother-reared infants. It is concluded that surrogate-reared infant squirrel monkeys do not show the same separation response or attachment to their rearing figure as do mother-reared infants.     

Partial cytochrome oxidase deficiency without subsarcolemmal accumulation of mitochondria in chronic progressive external ophthalmoplegia

Chronic progressive external ophthalmoplegia (CPEO) associated with proximal myopathy and/or craniosomatic abnormalities is a rare syndrome in which morphological mitochondrial changes have been found in some fibres (subsarcolemmal accumulation of mitochondria or "ragged red" fibres). We report a 14-year-old boy with CPEO and a mild proximal myopathy without these characteristic "ragged red" fibres. Histochemistry of skeletal muscle showed a mosaic of fibres without detectable cytochrome oxidase activity, while other mitochondrial enzymes were normal. The total cytochrome oxidase activity and cytochrome aa3 concentration in muscle mitochondrial fractions were only 40% of normal. This case is unique in that a biochemical defect was not accompanied by morphological abnormalities and may represent an early stage of CPEO before the development of morphological changes, or alternatively, a new variant of the disease.