树突状细胞与1型糖尿病的关系

1型糖尿病是一种T淋巴细胞介导的器官特异性自身免疫性疾病,表现为胰岛β细胞的选择性破坏.树突状细胞(DCs)作为体内最重要的专职性抗原递呈细胞,在1型糖尿病的发病机制中具有极其重要的作用.DCs具有功能上的可塑性,不同类型DCs、不同成熟状态的DCs以及DCs所处微环境的不同,都将诱导其产生不同的功能状态.通过调节DCs的不同功能状态促进中枢或外周免疫耐受、扩展胰岛特异性调节性T细胞(CD4~+ CD25~+ Treg cell)、以及介导辅助性T(Th)细胞发生Th1/Tk2细胞的免疫偏离,可诱导免疫耐受,预防1型糖尿病的发生.     

慢性乙型肝炎患者CD11c+髓样树突状细胞数量和功能的变化

BV形成免疫耐受是其持续感染的主要原因.树突状细胞(DC)作为体内最强的抗原递呈细胞,在诱导HBV特异性细胞毒T淋巴细胞反应中起重要作用[1].其中外周血DCs前体CD11c+髓样树突状细胞(mDC)主要发挥抗原提呈功能,促进Th1细胞极化和细胞免疫的发生[2].     

树突状细胞在慢性阻塞性肺疾病发病过程中的作用

树突状细胞(dendrtic cells,DCs)是目前发现的体内功能最强的抗原递呈细胞(antigen presenting cells,APC),在免疫应答中有着的独特的地位.越来越多的证据表明,呼吸道DCs不仅能诱导外界吸入抗原致敏,而且还能显著刺激初始型T细胞向Thl或Th2分化,而且在调节T细胞免疫应答、维持气道炎症和免疫耐受等方面都起着重要的作用.因此关于DCs在慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)中作用机制的相关研究将为临床治疗COPD研究提供新思路.     

树突状细胞在慢性阻塞性肺疾病发病过程中的作用

树突状细胞（dendrtic cells,DCs）是目前发现的体内功能最强的抗原递呈细胞（antigen presenting cells,APC）,在免疫应答中有着的独特的地位。越来越多的证据表明,呼吸道DCs不仅能诱导外界吸人抗原致敏,而且还能显著刺激初始型T细胞向Thl或Th2分化,而且在调节T细胞免疫应答、     

支气管哮喘与免疫调节

支气管哮喘（哮喘）是由环境过敏原引起基因易感人群Th1／Th2免疫失衡,Th2功能亢进而引起的。产生Th2细胞因子的CD4^＋T细胞在哮喘发生过程中起了关键的作用。各种特异性致炎因子,调节性T细胞,抗原递呈细胞以及免疫球蛋白都参与了哮喘的发生,本文就哮喘与免疫调节的关系以及免疫治疗的前景作一综述。     

炎性树突状细胞的功能特性及在支气管哮喘发病机制中的作用

树突状细胞是功能最强的专职抗原递呈细胞,作为机体免疫应答的启动者在免疫应答中占有重要地位.研究显示在感染或炎症状态下由炎性单核细胞分化而来的一种树突状细胞亚型——炎性树突状细胞,参与调节免疫应答.近来,炎性树突状细胞在支气管哮喘发生机制中的作用备受关注,现就炎性树突状细胞在不同类型免疫应答的作用及其与支气管哮喘的关系作一综述.     

树突细胞及其调节细胞免疫功能的作用

<正>早在19世纪70年代,Steinman等~〔1〕分离出一类细胞,与粒细胞、巨噬细胞和淋巴细胞的形态和功能都不同,由于这类细胞在成熟时会有许多树突样或伪足样突起伸出,故被命名为树突细胞(DCs)。DCs是目前已知的机体抗原提呈功能最强的专职抗原提呈细胞,在体内捕获抗原并将其提呈给辅助性T淋巴细胞(Th)从而发挥免疫防御的功能~〔2〕。DCs分布比较广泛,肝、脾、淋巴组织、血液、皮肤黏膜等组织均有,能够活化介导适     

自身免疫病与树突状细胞免疫调控

树突状细胞（dendriti cells，DCs）是已知功能最强的专职抗原提呈细胞（professional antigen-presenting cells，APC）。DCs活化静止性T细胞的效率是其他APC（如巨噬细胞等）的1000倍。同时，作为APC，它能惟一激活初始型T细胞（naive T cells）致敏，产生初次免疫应答。成熟DCs联合抗原作用可加强免疫应答，而不成熟DCs又可诱导抗原特异性T细胞克隆清除（无能）或产生调节T细胞（Tr），产生免疫抑制或免疫耐受。因此，DCs被视为重要的免疫调节工具。有望应用于自身免疫病、慢性病毒感染和肿瘤等一系列疾病的临床治疗。本文就DCs免疫凋控与自身免疫病关系综述如下。     

树突状细胞与慢性乙型肝炎

慢性乙型肝炎(chronic hepatitis B,CHB)患者免疫功能发生紊乱,导致持续性肝细胞损害,影响对病毒的清除能力.树突状细胞(dendriticcells,DCs)是体内最主要的抗原递呈细胞,激发机体能够针对外界病原体的侵入产生足够的免疫反应,其数量、功能正常与否直接影响机体的免疫应答.他不仅可以作为宿主抗病毒的功能细胞,也可以作为有利于病毒传播和逃避免疫损伤的载体.因此,对CHB状态下DCs性质的研究及功能提高途径的探索具有重要意义.     

树突状细胞与慢性阻塞性肺疾病

COPD是严重危害公众健康的重大疾病，免疫功能失调是其发病的主要机制之一。树突状细胞（dendriticcells，DCs）作为目前已知功能最强的抗原递呈细胞，在COPD免疫功能失调中发挥关键作用。近年来，DCs在COPD发病过程中的作用越来越引起关注。本文就DCs在COPD发生和发展中的作用进行综述。     

消化系恶性肿瘤病人LAK细胞和NK细胞功能与表型的变化

通过观察20例正常人和24例消化系恶性肿瘤病人外周血自然杀伤细胞(NK)和淋巴因子激活的杀伤细胞(LAK)的活性变化,以及加用重组白细胞介素2(rIL-2)刺激前后T淋巴细胞表型变化。结果发现肿瘤病人的NK细胞活性明显下降,但经rIL-2激活后LAK细胞活性得到明显提高,其溶解率接近正常水平。肿瘤病人的总T淋巴细胞(CD_(3+))和辅助/诱导T淋巴细胞(CD_(4+))水平低于正常,但抑制/杀伤淋巴细胞(CD_(8+))水平正常。辅助/诱导淋巴细胞与抑制/杀伤淋巴细胞之比为1.18,低于正常水平(1.55)。经加入rIL-2培养后,CD_(3+)和CD_(8+)淋巴细胞的比率明显升高并达正常水平。而在正常人此变化不明显,且加用rIL-2培养与不加者无显著差异。IL-2受体的表达正常人与肿瘤病人无异。结果显示胃肠道恶性肿瘤病人的免疫机制受到抑制,但能被IL-2提高至正常水平。     

Robust measurement of telomere length in single cells

Measurement of telomere length currently requires a large population of cells, which masks telomere length heterogeneity in single cells, or requires FISH in metaphase arrested cells, posing technical challenges. A practical method for measuring telomere length in single cells has been lacking. We established a simple and robust approach for single-cell telomere length measurement (SCT-pqPCR). We first optimized a multiplex preamplification specific for telomeres and reference genes from individual cells, such that the amplicon provides a consistent ratio (T/R) of telomeres (T) to the reference genes (R) by quantitative PCR (qPCR). The average T/R ratio of multiple single cells corresponded closely to that of a given cell population measured by regular qPCR, and correlated with those of telomere restriction fragments (TRF) and quantitative FISH measurements. Furthermore, SCT-pqPCR detected the telomere length for quiescent cells that are inaccessible by quantitative FISH. The reliability of SCT-pqPCR also was confirmed using sister cells from two cell embryos. Telomere length heterogeneity was identified by SCT-pqPCR among cells of various human and mouse cell types. We found that the T/R values of human fibroblasts at later passages and from old donors were lower and more heterogeneous than those of early passages and from young donors, that cancer cell lines show heterogeneous telomere lengths, that human oocytes and polar bodies have nearly identical telomere lengths, and that the telomere lengths progressively increase from the zygote, two-cell to four-cell embryo. This method will facilitate understanding of telomere heterogeneity and its role in tumorigenesis, aging, and associated diseases.Telomeres are the ribonucleoprotein structures that cap and protect linear chromosome ends from genomic instability and tumorigenesis (1, 2). Intriguingly, telomere shortening protects against tumorigenesis by limiting cell growth (3, 4), but also can impair tissue regenerative capability and cell viability (5, 6).Thus far, most assays of telomere length measure average telomere length from aggregates of many cells derived from dissected tissues, cultured cells, or blood (7). Telomere restriction fragment (TRF) determination (1, 8), a Southern blot-based technique, remains the “gold standard” for determining absolute telomere length, but requires a large amount of starting material (0.5–5 µg DNA) and several days for processing. Moreover, the requirements for gel electrophoresis and hybridization limit the scalability of this assay. Recently, a quantitative PCR (qPCR)-based method for telomere length measurement was developed, providing the convenience and scalability of PCR (9). Although the DNA requirement (35 ng) for qPCR is significantly less than TRF, it still relies on populations of cells to derive sufficient amount of DNA.Quantitative FISH (Q-FISH) allows sensitive visualization of relative telomere length from individual cells and individual telomeres, but this method requires many cells or metaphase arrested cells, which precludes its application to many sample types, including postmitotic cells, senescent cells, and other nondividing cells, and when only one actual cell is required to test. In addition, preparing chromosome spreads requires significant technical skill, and only proliferating cells within a population reach metaphase stage, so this analysis potentially biases the estimates of telomere length for a given cell population (10–12). High-throughput Q-FISH, flow FISH, and single telomere length analysis can be used for telomere measurement of dividing, nondividing, and senescent cells, but these methods also require large cell populations (13–15).The ability to measure telomere length in single cells rather than relying upon average telomere length in cell populations or the entire tissue enables the study of biological heterogeneity on a cell-by-cell basis, an issue of fundamental importance for studies of aging, development, carcinogenesis, and many other diseases. Here, we demonstrate an accurate determination of telomere length in individual cells, with the resolution and scalability of the qPCR telomere length assay.The basis of qPCR is that within a given cell, the ratio of the copy number of telomere repeats to the copy number of a multicopy reference gene is fixed (3), and this method, because of its simplicity, has been widely used to investigate a variety of telomere shortening-associated diseases (7), even sensitive enough to identify mild telomere dysfunction resulting from chronological life stress (16, 17). We adapted qPCR to measure telomere length in individual cells by using a preamplification step that specifically targets both the telomere and multicopy genes, followed by a qPCR assay to obtain telomere to reference gene (T/R) ratio. A single-cell telomere (SCT) length measurement method (SCT-pqPCR) runs robustly, and shows an identical T/R ratio for two sister blastomeres from two-cell–stage mouse embryos. The average result from SCT-qPCR with multiple single cells is linearly correlated to Q-FISH, TRF, and conventional qPCR assays designed for a large number of cells. The heterogeneity of telomere length among several populations of cells by SCT-pqPCR run on multiple single cells is consistent with—and sometimes superior to—results obtained by Q-FISH. Application of SCT-pqPCR to study telomere length during early embryo development, aging, and cancer demonstrate the value of this single-cell telomere length assay method.     

Processivity of peptidoglycan synthesis provides a built-in mechanism for the robustness of straight-rod cell morphology

The propagation of cell shape across generations is remarkably robust in most bacteria. Even when deformations are acquired, growing cells progressively recover their original shape once the deforming factors are eliminated. For instance, straight-rod-shaped bacteria grow curved when confined to circular microchambers, but straighten in a growth-dependent fashion when released. Bacterial cell shape is maintained by the peptidoglycan (PG) cell wall, a giant macromolecule of glycan strands that are synthesized by processive enzymes and cross-linked by peptide chains. Changes in cell geometry require modifying the PG and therefore depend directly on the molecular-scale properties of PG structure and synthesis. Using a mathematical model we quantify the straightening of curved Caulobacter crescentus cells after disruption of the cell-curving crescentin structure. We observe that cells straighten at a rate that is about half (57%) the cell growth rate. Next we show that in the absence of other effects there exists a mathematical relationship between the rate of cell straightening and the processivity of PG synthesis—the number of subunits incorporated before termination of synthesis. From the measured rate of cell straightening this relationship predicts processivity values that are in good agreement with our estimates from published data. Finally, we consider the possible role of three other mechanisms in cell straightening. We conclude that regardless of the involvement of other factors, intrinsic properties of PG processivity provide a robust mechanism for cell straightening that is hardwired to the cell wall synthesis machinery.     

特应性皮炎的免疫学发病机制

特应性皮炎是慢性复发性炎症性皮肤疾病，发病机制复杂，其中变态反应因素在发病机制中扮演着重要角色。目前认为Th1／Th2平衡失调是特应性皮炎重要的发病机制。本文围绕这一机制综述T细胞、树突状细胞、角质形成细胞及IgE在特应性皮炎发病机制中的作用。     

Regenerative medicine for the treatment of heart disease

Heart failure is a major cause of mortality worldwide with a steady increase in prevalence. There is currently no available cure beyond orthotopic heart transplantation, which for a number of reasons is an option only for a small fraction of all patients. Considerable hope has therefore been placed on the possibility of treating a failing heart by replacing lost cardiomyocytes, either through transplantation of various types of stem cells or by boosting endogenous regenerative mechanisms in the heart. Here, we review the current status of stem and progenitor cell‐based therapies for heart disease. We discuss the pros and cons of different stem and progenitor cell types that can be considered for transplantation and describe recent advances in the understanding of how cardiomyocytes normally differentiate and how these cells can be generated from more immature cells ex vivo. Finally, we consider the possibility of activation of endogenous stem and progenitor cells to treat heart failure.     

白藜芦醇对人肾癌细胞增殖和细胞周期的影响

目的探讨白藜芦醇（Res）对人肾癌细胞786-0（以下简称肾癌细胞）增殖和周期的影响。方法分别采用12.5、25、50、100μmol/L的白藜芦醇（Res）作用于肾癌细胞24 h;并设空白对照组。流式细胞仪检测细胞细胞周期。结果各浓度Res对肾癌细胞增殖均具有明显的抑制作用,表现为G1期及G2期细胞比例明显降低,S期比例明显升高,与对照组比较,P均〈0.05。Res 12.5μmol/L与25、50及100μmol/L比较,P均〈0.05;但25μmol/L与50、100μmol/L比较,P〉0.05。12.5μmol/L的Res抑制作用明显,当浓度达到25μmol/L时,抑制作用达最强;而继续升高浓度不能提高抑制作用。结论 Res对人肾癌细胞增殖有抑制作用,且具有剂量依赖性。     

骨髓干细胞移植在心血管疾病中的应用

近年来的研究表明，骨髓干细胞向心肌细胞分化已成为可能，动物模型及临床应用均证实，将骨髓干细胞移植于受损心肌可改善心肌缺血及心脏功能。     

Propagation of large numbers of T cells with natural killer cell markers

Summary. Previously, a subset of T cells co-expressing the NK cell antigen CD56 has been described. These CD3⁺CD56⁺ cells are rare in peripheral blood collections and have been poorly characterized. We have developed culture conditions which allow for the rapid expansion of CD3⁺CD56⁺ cells. The protocol for cellular expansion includes the addition of interferon-gamma on day O, interleukin-1, interleukin-2 and a monoclonal antibody against CD3 on day 1 to peripheral blood lymphocytes. Cells of the CD3⁺CD56⁺ phenotype increased up to 6000-fold using this protocol after 16 d in culture. These cells have been characterized by flow cytometry and have been found to express the alpha, beta T cell receptor, co-express the CD5 and CD8 antigens and do not express the CD16 antigen. Morphologically, these cells cannot be distinguished from NK cells. CD3⁺CD56⁺ killer cells lyse a variety of tumour cells with intermediate activity between CD3^?CD56⁺ NK cells and CD3⁺CD56^? T cells.     

肺干细胞研究进展

干细胞研究是现代医学领域研究热点之一.肺部疾病所导致的不同程度呼吸系统病理改变和功能受损,都伴随着肺组织的修复和重塑过程.对于肺部疾病的干细胞研究和应用尚有许多问题有待进一步的明确和探索.肺干细胞包括了肺组织自身的干细胞修复和肺外组织来源的干细胞修复.肺组织内的干细胞包括肺内上皮性干细胞、肺问充质干细胞、肺侧群细胞;其中肺内上皮性干细胞又包括了基底细胞、Clara细胞、Ⅱ型肺泡上皮细胞、"芽孢"样细胞.肺外组织来源的干细胞修复包括骨髓间充质干细胞和造血干细胞.干细胞治疗方法在临床上有巨大的应用前景.