干细胞技术与肝硬化:共性与个性的新实践

干细胞横向分化(transdifferentiation)的能力,在肝脏再生过程中发挥作用,随着对干细胞的深入研究,干细胞技术为终末期肝病的治疗提供了新思路。本文对干细胞加以分类并综述了各种干细胞研究进展,对干细胞在肝脏疾病细胞治疗上的应用及前景作了总结和展望。     

Fabricated Humans? Human Genetics,Ethics and the Christian Wisdom Tradition1

Abstract: This article highlights the key social issues associated with genetic screening and testing. It identifies an uneasy combination of a cultural drive towards perfection alongside heightened perception of a risk society. Awareness of risk is particularly in evidence in clinical genetics, but is surprisingly silent in public discourse about stem cell research, which has tended to flounder through its unilateral focus on the status of the early embryo. This article concentrates on current practice, such as the use of preimplantation genetic diagnosis, and offers a critical analysis of current debates about ethical issues. It argues that Christian ethics can contribute positively to the debate by drawing on the tradition of prudence or practical wisdom, which goes beyond the secular alternatives of both the consequential analysis of risk and benefit and the precautionary principle.     

人类干细胞之伦理原则与监管政策（上）

本文分两大部分。第一部分从干细胞的功能、来源与社会争议性3种角度划分了人类干细胞的种类,并讨论与人类干细胞研究及临床应用相关的9条伦理原则,特别强调了西方国家对胚胎捐赠在知情同意方面的伦理耍求。第二部分讨论了制定监管人类干细胞研究的3个原则,并简单地介绍了在英美各国监管的情况,其中较详细地评论了英国的种种立法过程、设立的法定机构和执行的种种政策与机制,作为在我国讨论类似政策参考之用。     

生殖性复制与医疗性复制之伦理区分

目前,各国政府和学术界对生殖性复制持否定态度是一致的,但对医疗性复制却存在激烈的争论。争论主要涉及人类胚胎的来源、胚胎的地位,以及胚胎干细胞成果应用的可接受性。     

Two types of serial dependence in visual working memory

Stimulus representations in working memory depend on memory traces of past stimuli both from previous trials and from the current trial. However, it is unclear whether the same or different mechanisms underlie this serial dependence across and within trials. We directly contrasted estimates of bias for pairs of immediately successive stimuli across and within trials. In each trial, participants memorized two consecutive motion direction stimuli (S1 and S2) and after a short delay were cued to report one of them. We found serial dependence across trials: The current S1 was attracted towards the preceding S2 when the latter had been cued for report. In contrast, within the same trial S2 was repulsed from S1. In addition, repulsion within a trial occurred for a broader range of motion direction differences between stimuli than attraction across trials. A second experiment in which 25% of trials did not require a response demonstrated that across‐trial attraction did not depend on whether the previous S2 actually had to be reported. Our findings provide evidence for two types of serial dependence operating across and within trials. They support the notion of different mechanisms integrating or segregating current from similar past memory contents depending on their task relevance.     

Specificity and variability of trunk kinematics on a mechanical horse

As perturbation training is gaining popularity, it is important to better understand postural control during complex three-dimensional stimuli. One clinically relevant and commonly used three-dimensional stimulus is found in hippotherapy and simulated hippotherapy on a mechanical horse. We tested nine healthy participants on a horse simulator, measured head and trunk kinematics, and characterized data in time (root-mean-square and variability) and frequency (amplitude spectra, gains, and phases) domains. We addressed three fundamental questions: 1) What is the specificity of postural responses to the simulator? 2) Which plane of motion is associated with the most and least variability (repeatable movements across repeated stimuli and across participants)? 3) To what extent are postural responses influenced by different degrees of stability (addition of pelvis straps and trunk support)? We found head and trunk responses were highly specific to the three-dimensional simulator perturbation direction and frequency. Frontal plane responses had the least variability across repetitions and participants whereas transverse motion was most variable. Head motion was more variable than the trunk at low frequencies and exhibited a marked decrease in tilt in the sagittal plane. Finally, the inclusion of pelvis straps had minimal effect on kinematics at low frequencies but altered higher frequencies; whereas added trunk support reduced head and trunk responses to perturbations and altered timing characteristics in all three planes. In conclusion, the present study suggests that frontal plane motion was under a high level of control, and results support the idea that specific head and trunk postural responses can be elicited from a complex three-dimensional stimuli, such as those found in hippotherapy. Researchers and clinicians can use results from this study to help interpret variability, implement mechanical adjustments to stability, and assess responses in pathological populations.     

骨髓造血干细胞移植治疗自身免疫性疾病的进展

自身免疫疾病发病机制复杂,目前尚缺少有效的治疗方法。近年来发现造血干细胞移植可以通过免疫重建显著缓解甚至治愈自身免疫病。笔者对近年来造血干细胞移植治疗自身免疫病进行了介绍和综述,就其在1型糖尿病这一领域的研究进展进行了述评,探讨造血干细胞移植用于治疗自身免疫病的前景和待解决的问题。     

辩证看待干细胞移植的热化问题

现代科学技术的发展已经并正在给人类展现一个相互矛盾的事实：一方面是科学技术推动人类社会的巨大进步,促进社会生活的极大提高。如核能的利用、转基因作物、转基因治疗、动物克隆、干细胞的开发与应用等等,无不让人类充分地享受到现代科技带来的种种利益和好处。另外一方面人类的生存危机前所未有的加深,环境的恶化、水资源的污染、新的疾病和变异的菌种诞生等等。怎样运用哲学的理性的思维和方法来评判现代科技对人类的影响,摆脱其发展对社会所造成的两难困境,是一个必须解决的难题。以干细胞移植研究为例,如何辩证看待干细胞移植热化问题,如何运用哲学思维来看待干细胞移植的有利性和危害性,探究科学技术的可持续发展道路。     

Human Allocentric Heading Orientation and Ability

ABSTRACT— Since the discovery of head-direction cells in nonhuman mammals, we have learned a great deal about how an internal compass-like system functions in the mammalian brain. In contrast, we know very little about how this system operates in humans—or, for that matter, whether humans even have an internal compass for computing body heading. This article reviews a recent line of inquiry that uses animal models of head-direction-system functioning to motivate behavioral research on human sense of direction.     

Development and validation of a measure to assess head start children's appraisals of teacher support

In this study, we present data on the development of Young Children's Appraisals of Teacher Support (Y-CATS), a measure designed to explore children's perceptions of their relations with teachers along dimensions that comprise warmth, conflict, and autonomy. Three cohorts of Head Start children and prior Head Start attendees (N=364) served as the sample. Cohort 1 children (n₁=108) were in first grade, cohort 2 children (n₂=123) were in kindergarten, and cohort 3 children (n₃=133) attended the Head Start program. Factor analyses supported a three-factor solution, with acceptable internal consistency, along hypothesized dimensions. Males, compared to females, reported more conflictual relationships with their teachers. Conflict scores were particularly pronounced for African American males. Children's reports on the Y-CATS were significantly associated with academic achievement and with teachers' ratings of social skills and behavior problems.