Spatial limits on referred touch to an alien limb may reflect boundaries of visuo-tactile peripersonal space surrounding the hand

In this study, the spatial limits of referred touch to a rubber hand were investigated. Participants rated the strength of the perceived illusion when the rubber hand was placed in one of six different spatial positions (at a distance of 17.5-67.5cm horizontal from the participant's own hand). The results revealed a significant nonlinear relationship in the strength of the illusion, with the strongest ratings given when the two hands were closest; decaying significantly after a distance of 30cm. The time taken to elicit the illusion followed a similar trend. These results may reflect the response properties of bimodal visuo-tactile cells encoding peripersonal space around the hand.     

BIOTECHNOTHEOLOGY AND DEMYTHOLOGIZATION OF STEM‐CELL RESEARCH

Biotechnology deals not only with new types of therapies for preventing and curing diseases but also with the creation of new technologies for the production of human flesh. Its ultimate aim is to create a new human body, a new person. Biotechnology wears the cloak not only of a new scientific paradigm but also of a kind of messianic religion. To develop new therapies, to destroy illnesses, to transform the human body into a nonmortal one—these are some of the promises it makes. In time, many of these promises will undoubtedly prove to be illusory, but they will nevertheless continue to have a significant impact on the way people think. Through a process that I call biotechnotheological analysis I show that biotechnology could eventually become not only a type of secular religion but even a type of mythic para‐Christian religion, one that incorporates the two most significant processes at work in every mythical religion: the process of mimesis and the ritual of the scapegoat. The essay is an attempt to understand biotechnological achievements, especially in stem‐cell research, in this new biotechnotheological way.     

胰岛细胞再生研究的临床应用前景

胰岛细胞再生是治愈1型糖尿病和胰岛β细胞功能丧失的2型糖尿病的根本途径。体外再生和体内再生两种策略都是通过将干细胞或其他类型体细胞分化或转化为胰岛细胞后发挥胰岛素分泌功能,从而治疗糖尿病。基础研究显示,两者存在着各自的优势和面临的问题。胰岛细胞再生治疗的临床应用前景尚需要进一步加以考证。     

Memory influences on hippocampal and striatal neural codes: effects of a shift between task rules

Interactions with neocortical memory systems may facilitate flexible information processing by hippocampus. We sought direct evidence for such memory influences by recording hippocampal neural responses to a change in cognitive strategy. Well-trained rats switched (within a single recording session) between the use of place and response strategies to solve a plus maze task. Maze and extramaze environments were constant throughout testing. Place fields demonstrated (in-field) firing rate and location-based reorganization [Leutgeb, S., Leutgeb, J. K., Barnes, C. A., Moser, E. I., McNaughton, B. L., & Moser, M. B. (2005). Independent codes for spatial and episodic memory in hippocampal neuronal ensembles. Science, 309, 619-623] after a task switch, suggesting that hippocampus encoded each phase of testing as a different context, or episode. The task switch also resulted in qualitative and quantitative changes to discharge that were correlated with an animal's velocity or acceleration of movement. Thus, the effects of a strategy switch extended beyond the spatial domain, and the movement correlates were not passive reflections of the current behavioral state. To determine whether hippocampal neural responses were unique, striatal place and movement-correlated neurons were simultaneously recorded with hippocampal neurons. Striatal place and movement cells exhibited a response profile that was similar, but not identical, to that observed for hippocampus after a strategy switch. Thus, retrieval of a different memory led both neural systems to represent a different context. However, hippocampus may play a special (though not exclusive) role in flexible spatial processing since correlated firing amongst cell pairs was highest when rats successfully switched between two spatial tasks. Correlated firing by striatal cell pairs increased following any strategy switch, supporting the view that striatum codes change in reinforcement contingencies.     

非雄激素依赖型前列腺癌与肿瘤干细胞——浅析辩证思维之于临床医学的方法论作用

在前列腺癌的治疗中,由于癌细胞的不断“升级”使得治疗屡屡受挫。近来提出的肿瘤干细胞理论认为:肿瘤是一种干细胞疾病,只有消灭了“种子”,才能克服癌症。从自然辩证法的角度,结合肿瘤干细胞理论对前列腺癌的诊疗加以分析,解释非雄激素依赖型前列腺癌的发病机制,以一种新的思维指导临床治疗。     

植入前组织配型孕育“救星同胞”的伦理思考

应用植入前遗传学诊断技术在胚胎植入母体子宫前,对人类白细胞组织相容性抗原配型检测,选择与现存患儿相同HLA配型的胚胎进行受孕,孕育一个组织配型相同的脐带血干细胞供者。在某种意义上说,该项技术的应用是创造人来获得移植组织,由此引发系列伦理争议。讨论孕育"救星同胞"这一医学实践内在需要的伦理规范。     

肿瘤干细胞与肿瘤治疗

肿瘤可看作是由功能异质性的细胞群体所组成的,具有不定增殖能力的异常器官.最近提出的肿瘤干细胞学说认为肿瘤起源于干细胞,肿瘤生长是肿瘤组织中极少量具有特殊细胞表面标志的肿瘤干细胞增殖的结果.因此治疗的关键应是针对肿瘤干细胞,通过靶向肿瘤干细胞及其异常调节的信号转导通路来治疗肿瘤.这对传统的治疗方式提出了巨大挑战,也为有效地根治肿瘤开辟了新的思路.     

干细胞技术应用于口腔医学的希望与困惑

骨髓干细胞、胚胎干细胞已开始应用于口腔医学领域,有关牙髓干细胞、牙周干细胞、牙胚干细胞等研究也取得了一系列重要的进展,为治疗口腔疾病开辟了一个新的途径,但同时也面临着需要进一步探讨的技术和伦理等方面的问题.     

联合国教科文组织国际生命伦理学委员会第七届会议报告

在厄瓜多尔政府的盛情邀请下,国际生命伦理学委员会(IBC)第七届会议于2000年11月7～9日在基多举行。来自50个国家的170余名学者到会。IBC讨论了两个工作小组关于胚胎干细胞研究伦理学问题及在人类基因组研究中发达国家与发展中国家之间的团结与合作问题的报告。几位专家召开了一次主题为“生命伦理学教育”的圆桌会议。IBC还就人类基因组研究中经济方面的问题召开了一次工作会议。     

胚胎干细胞在治疗学研究中的应用

目前有许多研究人员希望能够从事胚胎干细胞的研究。这项研究可能对可移植组织用于对目前认为难以治疗或不能治疗的许多疾病的治疗的发展带来极大的帮助。然而,由于干细胞是源自人体胚胎。这就提出了如下问题：为了治疗学研究,在胚胎植入子宫之前从人类胚胎上获取细胞以从事实验室培养和研究在伦理上能够被接受吗?不同国家的伦理委员会或国家立法机构关于胚胎研究的观点及其采取的解决办法可能存在显著差异。这种差异在多元性世界里是不可避免的。