Committing embryonic stem cells to early endocrine pancreas in vitro

A panel of genetic markers was used to assess the in vitro commitment of murine embryonic stem (ES) cells toward the endoderm-derived pancreas and to distinguish insulin-expressing cells of this lineage from other lineages such as neuron, liver, and yolk sac. There are two nonallelic insulin genes in mice. Neuronal cells express only insulin II, whereas the pancreas expresses both insulin I and II. Yolk sac and fetal liver express predominately insulin II, small amounts of insulin I, and no glucagon. We found that ES-derived embryoid bodies cultured in the presence of stage-specific concentrations of monothio-glycerol and 15% fetal calf serum, followed by serum-free conditions, give rise to a population that expresses insulin I, insulin II, pdx-1 (a pancreas marker), and Sox17 (an endoderm marker). Immunohistochemical staining shows intracellular insulin particles, and its de novo production was confirmed by staining for C-peptide. Most, but not all, of the insulin+ or C-peptide+ cells coexpress glucagon, demonstrating a differentiation pathway to pancreas rather than yolk sac or fetal liver. Addition of beta-cell specification and differentiation factors activin beta B, nicotinamide, and exendin-4 to later-stage culture increased insulin-positive cells to 2.73% of the total population, compared with the control culture, which gave rise to less than 1% insulin-staining cells. These findings suggest that stepwise culture manipulations can direct ES cells to become early endocrine pancreas.     

幼师生自尊与心理健康的相关研究

目的 检验幼师女生自尊水平与心理健康的关系。方法 使用自尊量表和SCL-90量表对196名幼师女生进行测量。结果 幼师女生的心理健康总体水平不高，幼师女生自尊水平与心理健康之间存在的显著的负相关。结论 一方面幼师女生的自尊受心理健康水平的影响，特别是抑郁、强迫和人际敏感等方面；另一方面幼师女生的自尊也会影响她们的心理健康水平。     

Genetic control of serum IgE levels: a study of low molecular weight protein tyrosine phosphatase

Protein tyrosine phosphatases (PTPases) have recently been recognized as important modulators of various signal transduction pathways in immune cells. Genetic polymorphisms have been described in genes codifying for members of this family of enzymes, and the genetics of PTPases is predicted to play an important role in the etiology of immune diseases and of their clinical variability. The low molecular weight protein tyrosine phosphatase (ACP1 or LMPTP) is one of the few PTPases with a known genetic polymorphism, and has been proposed to be associated with atopic dermatitis in a small sample from an Italian population. In this paper we describe the association of the ACP1 polymorphism with total IgE levels in two independent samples from English and Italian populations. In both the samples the mean value of serum IgE is lower among subjects carrying the BC genotype than in other ACP1 genotypes. The BC genotype is associated with the highest total ACP1 enzymatic activity. Our data suggest that one or both of the ACP1 isoforms exert an inhibitory role on some signal transduction pathway relevant for IgE hyperproduction.     

Effective induction of immune tolerance by portal venous infusion with IL-10 gene-modified immature dendritic cells leading to prolongation of allograft survival

Dendritic cells (DC) not only initiate T cell responses, but are also involved in the induction of tolerance. The functional properties of DC are strictly dependent on their state of maturation. It has been shown that immature DC can induce immune tolerance and prolong allograft survival. Interleukin-10 (IL-10) is an important immunosuppressive cytokine which inhibits maturation and function of DC. In order to improve the tolerogenicity of DC, we and others showed that adenovirus vectors can effectively mediate IL-10 genetic modification of DC, and IL-10 genetic modification can inhibit MHC II, B7.2, and CD40 expression, IL-12 secretion and the T cell stimulatory capacity of DC. The primary aim of this study is to examine the in vivo effects of this approach on allograft survival in a murine cardiac allograft transplantation model. To our surprise, we observed that infusion of immature DC genetically modified to express IL-10 (DC-IL-10) via the tail vein could not prolong allograft survival in the recipients, but shortened their survival. More interestingly, portal venous infusion of DC-IL-10 markedly prolonged allograft survival. The diverse effects of DC-IL-10 infusion through different routes may be due to the different immune responses to alloantigens in recipients that received DC-IL-10 via either the portal or the tail vein. Decreased cytotoxicity, polarization of Th2 response, poor T cell stimulating activity of liver DC and enhanced incidence of donor DC in the recipients may contribute to the more efficient prolongation of allograft survival observed after portal venous infusion of DC-IL-10. These results suggest that portal venous infusion may be an effective approach for immature DC to induce immune tolerance or hyporesponsiveness against donor antigens, and prolong allograft survival.Abbreviations APC Antigen-presenting cells - CTL Cytotoxic T lymphocytes - DC Dendritic cells - DC-IL-10 IL-10 gene-modified immature dendritic cells - iDC Immature dendritic cells - IL-10 Interleukin-10 - MLR Mixed leukocyte reaction - MOI Multiplicity of infection     

类风湿性关节炎患者外周血及滑膜液中Ⅱ型胶原反应性B细胞频率分析

以一个ＣＤ４＋Ｔ细胞克隆（ＥＬ－４，克隆ＯＵｒＢＵｒ）和ＰＭＡ、ｒＩＬ－２做为多克隆刺激系统，应用酶联斑点（ＥＬＩＳＰＯＴ）技术从单细胞水平检测了类风湿性关节炎（ＲＡ）、非类风湿性关节炎（Ｎｏｎ－ＲＡ）患者外周血及滑膜液中Ⅱ型胶原特异性抗体产生细胞频率。发现ＲＡ患者外周血及滑膜液中Ⅱ型胶原反应性Ｂ细胞频率明显高于Ｎｏｎ－ＲＡ患者。提示单纯软骨结构的破坏并不能解释Ⅱ型软骨胶原在免疫病理损伤中的作用，因为Ｎｏｎ－ＲＡ患者关节局部也存在着严重的炎症反应。     

High density of immobilized galactose ligand enhances hepatocyte attachment and function

Galactosylated surface is an attractive substrate for hepatocyte culture because of the specific interaction between the galactose ligand and the asialoglycoprotein receptor on hepatocytes. In this study, we described a scheme to achieve high density of immobilized galactose ligands on polyethylene terephthalate (PET) surface by first surface-grafting polyacrylic acid on plasma-pretreated PET film under UV irradiation, followed by conjugation of a galactose derivative (1-O-(6'-aminohexyl)-D-galactopyranoside) to the grafted polyacrylic acid chains. A high galactose density of 513 nmol/cm(2) on the PET surface was used in this study to investigate the behavior of cultured hepatocyte. This engineered substrate showed high affinity to fluorescein isothiocyanate-lectin binding. Primary rat hepatocytes, when seeded at a density of 2 x 10(5) cells/cm(2), attached to the galactosylated PET substrate at a similar efficiency compared with collagen-coated substrate. The hepatocytes spontaneously formed aggregates 1 day after cell seeding and showed better maintenance of albumin secretion and urea synthesis functions than those cultured on collagen-coated surface.     

双特异性抗体对LAK细胞增殖和细胞毒作用影响的体外研究

将抗ＣＤ３与抗ＨＢｓ的单克隆抗体经化学偶联得到双特异性抗体，观察该双特异性抗体对ＬＡＫ细胞增殖和增强细胞毒性的作用。结果显示双特异性抗体显著提高ＬＡＫ细胞与２．２．１５细胞结合率；促进淋巴细胞增殖。１２５Ｉ－ＵｄＲ释放试验检测发现双特异性抗体增强ＬＡＫ细胞对２．２．１５细胞的细胞毒性且与抗体浓度呈正相关。进一步对抗体的特异性研究表明，加入双特异性抗体后ＬＡＫ细胞对２．２．１５细胞毒性作用显著高于对照组。