伦理,胚胎和干细胞研究

道德是关于规则、直觉、理解和观点的一个复杂系统。而后者影响着我们相互间处理事务的方式。它们交叉地渗入我们的道德思考。这种思维与胚胎、干细胞的伦理密切相关,因为胚胎和干细胞涉及我们对与治疗和移植组织有关的人的生命及其启始问题。就像在许多对待生命及其可以阐释的研究方法方面,要有一个道德的思辩历程一样,解决这些问题,部分地需要讨论,部分地需要回答。只有在我们认定这种讨论能够融入应用干细胞治疗的胚胎及其类源和人体组织的使用中时,我们才会清楚,大多数人体不同部位的干细胞应用是经过了对人的生命启始、我们儿童、家庭进行了思考。     

造血干细胞移植资格准入的相关问题

通过探讨目前我国开展造血干细胞移植(HSCT)存在的问题,介绍开展HSCT的基本要求,引入准入制度的重要意义来保护这项医疗技术不被滥用,使其最终的结果是HSCT的技术得到稳步提高,移植质量得到有效保障。     

The levels of perceptual processing and the neural correlates of increasing subjective visibility

According to the levels-of-processing hypothesis, transitions from unconscious to conscious perception may depend on stimulus processing level, with more gradual changes for low-level stimuli and more dichotomous changes for high-level stimuli. In an event-related fMRI study we explored this hypothesis using a visual backward masking procedure. Task requirements manipulated level of processing. Participants reported the magnitude of the target digit in the high-level task, its color in the low-level task, and rated subjective visibility of stimuli using the Perceptual Awareness Scale. Intermediate stimulus visibility was reported more frequently in the low-level task, confirming prior behavioral results. Visible targets recruited insulo-fronto-parietal regions in both tasks. Task effects were observed in visual areas, with higher activity in the low-level task across all visibility levels. Thus, the influence of level of processing on conscious perception may be mediated by attentional modulation of activity in regions representing features of consciously experienced stimuli.     

干细胞移植治疗冠心病的现状与未来

冠心病仍然是全球的主要死亡原因.其所造成的心肌梗死及慢性心力衰竭对生活质量的影响和由此造成的高额医疗费用促使我们不断寻求新的医疗措施.近几年有关干细胞用于心肌梗死后心肌再生、心肌内新生血管形成,可能还会改善梗死后的心功能的研究成为心脏病学研究的最热门领域.尽管干细胞治疗有可能使心力衰竭的治疗得到彻底的革命,但仍有部分问题需要澄清.已发表的各个研究结果设计不尽相同,致使对该项治疗的效果较难得出一致的结论.但这些研究都强调干细胞治疗在未来心血管疾病的治疗中可能会发挥较大的作用.干细胞治疗与药学、外科及介入治疗的结合会显著改善冠心病患者的预后.     

Identification and integration of sensory modalities: Neural basis and relation to consciousness

A key question in studying consciousness is how neural operations in the brain can identify streams of sensory input as belonging to distinct modalities, which contributes to the representation of qualitatively different experiences. The basis for identification of modalities is proposed to be constituted by self-organized comparative operations across a network of unimodal and multimodal sensory areas. However, such network interactions alone cannot answer the question how sensory feature detectors collectively account for an integrated, yet phenomenally differentiated experiential content. This problem turns out to be different from, although related to, the binding problem. It is proposed that the neural correlate of an enriched, multimodal experience is constituted by the attractor state of a dynamic associative network. Within this network, unimodal and multimodal sensory maps continuously interact to influence each other’s attractor state, so that a feature change in one modality results in a fast re-coding of feature information in another modality. In this scheme, feature detection is coded by firing-rate, whereas firing phase codes relational aspects.     

Influence of dorsal hippocampal lesions and MMP inhibitors on spontaneous recovery following a habituation/classical conditioning head–shake task

The present investigation combined a classical conditioning paradigm with a head–shake response (HSR) habituation task in order to evaluate the importance of dorsal hippocampal neural plasticity to spontaneous recovery. In the first experiment animals exhibited rapid HSR habituation (air stimulus to the ear) and an 85% level of spontaneous recovery following a 24 h inter-session interval. The addition of a brief tone prior to the air stimulus produced a similar pattern of habituation during the first session, but the level of spontaneous recovery was reduced (44%) during Session II. In a second experiment dorsal hippocampal lesioned rats placed on this tone/HSR paradigm responded with an 87% level of spontaneous recovery during Session II; while neocortex lesioned control rats indicated significantly reduced levels of spontaneous recovery (55%). In a third experiment bilateral injections of a general MMP inhibitor, FN-439, into the dorsal hippocampus resulted in high levels of spontaneous recovery (81%); while control rats injected with artificial cerebrospinal fluid displayed a significant attenuation of spontaneous recovery (45%). Finally, animals bilaterally injected with a specific MMP-3 inhibitor into the dorsal hippocampus indicated very similar results to those obtained following FN-439 injection. These findings indicate that animals prepared with dorsal hippocampal lesions, or injections with an MMP inhibitor, revealed an impaired association between the tone and air stimulus thus maximum spontaneous recovery was present 24 h later. Thus, it appears that the dorsal hippocampus influences habituation by conserving responses and reducing spontaneous recovery when a temporally contingent signaling cue is present.     

Perception with compensatory devices: from sensory substitution to sensorimotor extension

Sensory substitution devices provide through an unusual sensory modality (the substituting modality, e.g., audition) access to features of the world that are normally accessed through another sensory modality (the substituted modality, e.g., vision). In this article, we address the question of which sensory modality the acquired perception belongs to. We have recourse to the four traditional criteria that have been used to define sensory modalities: sensory organ, stimuli, properties, and qualitative experience ( Grice, 1962 ), to which we have added the criteria of behavioral equivalence ( Morgan, 1977 ), dedication ( Keeley, 2002 ), and sensorimotor equivalence ( O'Regan & Noë, 2001 ). We discuss which of them are fulfilled by perception through sensory substitution devices and whether this favors the view that perception belongs to the substituting or to the substituted modality. Though the application of a number of criteria might be taken to point to the conclusion that perception with a sensory substitution device belongs to the substituted modality, we argue that the evidence leads to an alternative view on sensory substitution. According to this view, the experience after sensory substitution is a transformation, extension, or augmentation of our perceptual capacities, rather than being something equivalent or reducible to an already existing sensory modality. We develop this view by comparing sensory substitution devices to other "mind-enhancing tools" such as pen and paper, sketchpads, or calculators. An analysis of sensory substitution in terms of mind-enhancing tools unveils it as a thoroughly transforming perceptual experience and as giving rise to a novel form of perceptual interaction with the environment.     

进展期非小细胞肺癌维持治疗进展

化疗在进展期非小细胞肺癌的地位已经确立,现有的方案已经达到“化疗疗效平台”。延长化疗无潜在益处,有什么办法可以保持现有的疗效。为此,提出了维持治疗的概念,维持治疗是指患者在完成标准的几个周期化疗且疾病得到控制后再接受的化疗,架起一二线治疗间的桥梁。带来进一步的临床获益。     

局限期小细胞肺癌放疗中预防野照射和累及野照射的疗效分析

局限期小细胞肺癌综合治疗中采用三维适型或调强放疗技术,按不同照射范围分为累及野照射和预防野照射2个组进行比较,分析不同照射野对预后的影响。 67例局限期小细胞肺癌患者,随机分为累及野照射组37例和预防野照射组30例。累及野照射组照射范围包括化疗前CT所见肿瘤及转移淋巴结范围,预防野照射组照射范围包括原发灶、同侧肺门、纵隔及锁骨上淋巴引流区。两组均采用三维适形或调强技术,放疗剂量为DT50Gy～66Gy/5周～6周。结果全组总有效率为82.1%,局部复发率为29.9%,远处转移率为56.7%,1年、2年、3年生存率分别为68.7%、36.2%和20.1%,分组比较以上指标均无显著性差异（P＞0.05）。而两组病例急性放射性肺炎和食道炎发生率分别为5.4%、16.7%和2.7%、20.0%,累及野照射食管炎发生率显著低于预防野（P＜0.05）。     

A neural model of how the brain computes heading from optic flow in realistic scenes

Visually-based navigation is a key competence during spatial cognition. Animals avoid obstacles and approach goals in novel cluttered environments using optic flow to compute heading with respect to the environment. Most navigation models try either explain data, or to demonstrate navigational competence in real-world environments without regard to behavioral and neural substrates. The current article develops a model that does both. The ViSTARS neural model describes interactions among neurons in the primate magnocellular pathway, including V1, MT⁺, and MSTd. Model outputs are quantitatively similar to human heading data in response to complex natural scenes. The model estimates heading to within 1.5° in random dot or photo-realistically rendered scenes, and within 3° in video streams from driving in real-world environments. Simulated rotations of less than 1°/s do not affect heading estimates, but faster simulated rotation rates do, as in humans. The model is part of a larger navigational system that identifies and tracks objects while navigating in cluttered environments.