干细胞移植治疗缺血性心脏病研究的新途径:miRNAs

miRNAs在干细胞的自我更新、多向分化及分泌血管活性物质等过程中扮演作非常重要作用。近年来人们对于干细胞移植术治疗缺血性心脏病,取得了一定的成果,但仍然存在着大量有待解决的问题。例如如何增加移植后的干细胞存活率;改善梗死区的微环境,增加迁移或归巢到梗死区干细胞的数量等,而miRNAs在干细胞中的调节机制且表明miRNAs有可能成为干细胞移植研究的一个新的切入点。     

光照的警觉性作用

光照除了传统的视觉作用外, 还具有一定的非视觉效应, 包括调节昼夜节律、褪黑素分泌和警觉性等生理功能和行为表现。随着光照对生理节律影响研究的不断深入, 近来很多学者开始关注光照的警觉性作用。我们根据最新研究进展总结了：(1)警觉性的测量工具; (2)光照强度、时长、时间点、波长、色温等对光照警觉性作用的影响; (3)光照在治疗情绪障碍、调节生理节律、完善办公照明方面的应用; (4)提出了继续探讨光照警觉性作用的神经机制、优化参数特征和探讨混淆变量的研究方向。     

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.

Latent class models for nonmonotone dichotomous items

Starting from perfectly discriminating nonmonotone dichotomous items, a class of probabilistic models with or without response errors and with or without intrinsically unscalable respondents is described. All these models can be understood as simply restricted latent class analysis. Thus, the estimation and identifiability of the parameters (class sizes and item latent probabilities) as well as the chi-squared goodness-of-fit tests (Pearson and likelihood-ratio) are free of the problems. The applicability of the proposed variants of latent class models is demonstrated on real attitudinal data.This research was supported by the Kulturamt der Stadt Wien, Magistratsabteilung 7.The author wishes to thank the editor, Ivo W. Molenaar, as well as Clifford C. Clogg and the anonymous reviewers for their valuable comments on the earlier drafts of this paper.     

Detection of subtype blood cells using deep learning

Deep Learning has already shown power in many application fields, and is accepted by more and more people as a better approach than the traditional machine learning models. In particular, the implementation of deep learning algorithms, especially Convolutional Neural Networks (CNN), brings huge benefits to the medical field, where a huge number of images are to be processed and analyzed. This paper aims to develop a deep learning model to address the blood cell classification problem, which is one of the most challenging problems in blood diagnosis. A CNN-based framework is built to automatically classify the blood cell images into subtypes of the cells. Experiments are conducted on a dataset of 13k images of blood cells with their subtypes, and the results show that our proposed model provide better results in terms of evaluation parameters.     

慢性乙型肝炎T细胞功能与HBV前C区变异的研究

通过研究慢性HBV感染者前C区变异及T细胞免疫功能与疾病的相关性,评估前C（preC）区变异及T细胞免疫功能对于慢性乙型肝炎（chronichepatitisB,CHB）预后的影响。分别采用实时荧光法、突变特异PCRmsPCR法及微粒酶免疫分析法对150例HBV-DNA阳性的CHB及50例健康体检者进行血清HBV-DN...     

克服肿瘤干细胞耐药性的策略和思路

肿瘤干细胞（cancersterncells,CSCs）是肿瘤细胞的祖细胞。已有的研究表明,肿瘤干细胞对多种化疗药物具有耐药性,是导致肿瘤治疗后复发的根源。研究针对肿瘤干细胞的治疗方法,克服肿瘤干细胞耐药性,将给肿瘤治疗模式带来全新的改变,有望彻底改善肿瘤患者的预后。     

慢性应激对大鼠行为和免疫细胞热休克蛋白70表达的影响

目的：研究慢性不确定应激对大鼠急性整体热水浴后外周血和脾脏免疫细胞热休克蛋白70（Heat shock protein 70, HSP70）表达的影响。方法：随机将大鼠分成慢性应激组和控制组（每组14只）。通过4周的慢性不确定性应激诱发实验组大鼠明显的抑郁行为,此期间控制组大鼠正常饲养。随后给予大鼠42度整体热水浴刺激,维持直肠温度41度25min。热刺激后6h,采用流式细胞仪测定大鼠外周血和脾脏免疫细胞HSP70 水平。结果：与控制组大鼠相比,慢性应激大鼠在急性热刺激后HSP70合成明显减少。控制组大鼠的所有被检测的免疫细胞热应激后HSP70合成均明显增加。相反,慢性应激大鼠仅在外周血的单核细胞和粒细胞检测到HSP70合成增加,同时升高的水平明显低于控制组大鼠。结论：慢性应激降低大鼠免疫细胞HSP70的热诱导反应,提示HSP70保护性作用减弱可能参与了慢性应激损害免疫细胞功能的生物学过程