血管干细胞与血管性疾病

血管性疾病是目前严重威胁人类健康的疾病之一。血管干细胞的提出及其技术的应用对传统的治疗方式提出了巨大的挑战,开辟了新的思路。但同时也面临着一系列的技术和社会问题,有待进一步的探讨。     

建立鼻腔结构与功能自适应生物力学模型在鼻科疾病中的作用

鼻腔结构在与鼻腔物理力学环境发生交互关系时,能够根据周围环境调整自身结构和形状,即所谓鼻腔结构与功能自适应性.鼻腔结构与功能自适应生物力学模型模拟鼻腔结构异常产生功能障碍所继发的上呼吸道疾病发生发展过程,为鼻科某些常见病的发生发展过程进行量化分析,为鼻内窥镜手术在恢复重建鼻腔结构功能方面临床决策提供依据.     

胃肠道干细胞

胃肠道是人体内各系统细胞更新频率最高的器官,其干细胞的增生分化也很旺盛。尽管胃肠道干细胞本身未分化成熟,其细胞表型无法确认而不利于鉴别,但随着一些干细胞标志物的发现及对细胞信号传导通路的不断了解,我们对胃肠道干细胞的调控机制的认识正在不断加深。胃肠道干细胞的基本特征:(1)胃肠道干细胞的数量、定位和组织起源;(2)胃肠道干细胞的主要功能,包括分化转化成胃肠道各成熟的细胞系及维持组织的动态平衡和稳定;(3)从其他组织的干细胞获得胃肠组织细胞系用以胃肠道疾病的治疗;(4)胃肠道组织癌变的基因变化及形态学观察。     

重视干细胞研究中的伦理问题

黄禹锡的“卵子风波”反映了干细胞研究领域中伦理规范的缺位。分析了针对干细胞研究的种种伦理争论,并且指出,由于与人类的尊严和幸福密切相关,生物医学领域的研究不能回避伦理问题,相关的伦理研究必须与科学研究同步进行。     

生育获得脐血行干细胞移植治疗重大遗传性疾病的风险和对策

通过生育获得脐带血行干细胞移植是治疗重大疾病的一条可行之路,但在治疗遗传性疾病时,当事家庭、检测机构和医疗机构三方都存在着极大的风险,特别是当事家庭很有可能要承受精神和经济上的更大打击,而且客观上造成患病或者携带者人群的进一步扩大,成为一个不可忽视的社会问题。有必要进行充分的伦理思考后提出尽可能周全的办法,以降低各方面的风险。     

ICU患者低磷血症临床观察与思考

回顾性分析41例低磷血症患者血磷水平与同期血气分析、血浆白蛋白(ALB)、尿素氮(BUN)等因素间关系及治疗前后急性生理和慢性健康评分(APACHE)Ⅱ的变化.结果显示脓毒症组血磷降低程度最明显,该组APACHEⅡ评分及纠正低磷血症所需时间显著高于其他基础疾病组.治疗前重度低磷血症组患者血pH、BUN显著高于轻中度低磷血症组,而PaCO2及ALB则明显低于轻中度低磷血症组;治疗前重度低磷血症组与轻中度低磷血症组间APACHE Ⅱ评分有显著差异,而治疗后两组间差异消失.病因治疗辅以适当补磷治疗可有效纠正低磷血症.由此得出结论,脓毒症患者易继发低磷血症.危重症患者重度低磷血症的发生与机体内酸碱环境改变及感染、高分解代谢等因素有关.低磷血症程度与疾病严重程度有关,但尚不足以成为独立的预后指标.     

干细胞移植治疗视网膜疾病的启示

干细胞是指具有自我更新、高度增殖和多向分化潜能的细胞群体,通过胚胎干细胞及视网膜干细胞、骨髓间充质细胞等成体干细胞移植治疗眼底病是近年来研究的热点,并取得了重要进展,为视网膜疾病的治疗开辟了新的途径,但同时也面临着技术的探讨及哲学的思考。本文就干细胞移植治疗视网膜疾病这一问题进行相关哲学思考。     

Anomalous brain dominance and the immune system: Do left-handers have specific immunological patterns?

Geschwind and Behan (1982) and Geschwind and Galaburda (1985a, 1985b, 1985c) suggested a correlation between brain laterality and immune disorders. To test whether this hypothesis holds true not only for the frequency of immune diseases and circulating autoantibodies, but extends also to cellular immunity, we examined the association between handedness and markers of cellular immunity. Twenty-seven left-handed and 37 right-handed subjects were serologically screened for cellular parameters and 22 left-handed subjects were typed for human leukocyte antigen (HLA). When compared to the right-handers, the left-handed group showed a significant decrease in the inflammatory cell types CD3(+) T cells (total T cells), CD4(+) T cells (T-helper cells), and HLA-Dr (MHC-II, antigen-presenting cells) as well as in the CD19(+) cells (B cells) and CD16/CD57(+) cells (natural killer cells). We assume a relationship exists between cerebral hemispheric specialisation and the immune system not only for humoral but also for cellular immunity, and we discuss the role of the major histocompatibility complex in neurological and immunological development.     

A model of episodic memory: Mental time travel along encoded trajectories using grid cells

The definition of episodic memory includes the concept of mental time travel: the ability to re-experience a previously experienced trajectory through continuous dimensions of space and time, and to recall specific events or stimuli along this trajectory. Lesions of the hippocampus and entorhinal cortex impair human episodic memory function and impair rat performance in tasks that could be solved by retrieval of trajectories. Recent physiological data suggests a novel model for encoding and retrieval of trajectories, and for associating specific stimuli with specific positions along the trajectory. During encoding in the model, external input drives the activity of head direction cells. Entorhinal grid cells integrate the head direction input to update an internal representation of location, and drive hippocampal place cells. Trajectories are encoded by Hebbian modification of excitatory synaptic connections between hippocampal place cells and head direction cells driven by external action. Associations are also formed between hippocampal cells and sensory stimuli. During retrieval, a sensory input cue activates hippocampal cells that drive head direction activity via previously modified synapses. Persistent spiking of head direction cells maintains the direction and speed of the action, updating the activity of entorhinal grid cells that thereby further update place cell activity. Additional cells, termed arc length cells, provide coding of trajectory segments based on the one-dimensional arc length from the context of prior actions or states, overcoming ambiguity where the overlap of trajectory segments causes multiple head directions to be associated with one place. These mechanisms allow retrieval of complex, self-crossing trajectories as continuous curves through space and time.     

Human embryonic stem cell research and the discarded embryo argument

Many who believe that human embryos have moral status are convinced that their use in human embryonic stem cell (hESC) research can be morally justified as long as they are discarded embryos left over from fertility treatments. This is one reason why this view about discarded embryos has played such a prominent role in the debate over publicly funding hESC research in the United States and other countries. Many believe that this view offers the best chance of a compromise between the different sides in this debate. This paper focuses on what seems to be the most plausible argument for this view about discarded embryos. It shows that this argument is unsound regardless of how one understands the claim that embryos have moral status. It also discusses the implications of this conclusion for attempts to use this argument as a basis for public policy.