脑瘤患者胎免疫组织细胞不同方式移植的临床研究

为了探讨脑瘤患者不同方式胎免疫组织细胞移植治疗效应，随机将脑瘤术后患者分为２组：接受胎胸腺组织移植患者４１例（下称单植组），接受胎胸腺组织及肝、脾细胞移植４３例（下称联植组）．观察患者临床症状、存活时间、监测移植前、后患者常规免疫指标，并采用荧光抗体技术测定抗胎胸腺抗体．结果，两组患者移植后临床全身症状开始逐渐好转，而联植组患者临床症状改善更为突出．植后患者的５ａ存活率单植组为５４％，联植组为６３％．两组患者中已死亡者平均存活时间超过Ｃａｒｓｏｎ氏和Ｚｕｌｃｈ的统计值．所测定的常规免疫指标移植前、后统计显示，Ｌｙｍ，Ｅ－ＲＦＣ，ＬＴＴ呈现极显著性差异（Ｐ＜０．０５）；ＩｇＧ，Ｃ３呈现显著性差异（Ｐ＜０．０５）；其它则未呈现显著性差异（Ｐ＞０．０５）；抗胎胸腺抗体检测结果阴性．结论，两组患者胎免疫组织细胞移植治疗效应联植组优于单植组．移植治疗能增强脑瘤术后患者的免疫功能．两组未见排异反应和移植物抗宿主反应．

Histological Study on Soybean Somatic Embryogenesis

Soybean somatic cell could induce the development of embryoid which was similar to embryo morphologically and structurally. Somatic embryogenesis system of soybean was used to conduct genetic transformation of soybean because of its several advantages such as higher transformational efficiency, beetter synchronism and fewer plant chimeras among transgenic plants. After infected with agrobacterium tumefaciens,the initiation, differentiation and development of young cotyledon embryogenic cell of soybean which was cultured on selective culture medium with kanamycin were investigated through histological study. The result showed that somatic embryo was differentiated in non-bud differentiation way. The embryogenic cells were differentiated from epidermis of explant or cells in 1 layer or 2 layers, with the division of embryogenic cells and degradation and disorganization of surrounding cells, the embryogenic cells would form embryoid with analogous suspensor structure. Later, globular embryoid would extrude from epidermis then developed into heart-shape embryo. The experiment was expected to provide theoretical reference for the construction of high transformational system of using plant somatic embryogenesis induced by young cotyledon of soybean.

人类寿命揭秘

延年益寿,健康地生活一百岁、二百岁,甚至更久远,这是人类千百年来的梦想。与人类祖先22岁的平均寿命相比,目前70岁以上的平均寿命,不能不说是一大进步。医学家们认为,随着医学科学的发展,人类将不断认识和揭示自身生命的奥秘,从而进一步延长自身寿命。 本世纪初,运用现代科学技术,人类开始了缓慢而艰苦的探索进程。1908年,俄国医生伊尔娃·麦茨尼克夫首次揭示人体肠道中的“有害微生物”会导致生命衰退,它们寄生在人体结肠中,不断地产生一种特殊的有毒物质,这些物质随时间推移,促使人体逐渐衰老、退化、死亡。故而,他告诫人们经常饮用酸奶,以涤除肠胃中的杂质,保持人类脏器的清洁。

Mesenchymal stem cells derived from human placenta suppress allogeneic umbilical cord blood lymphocyte proliferation

Human placenta-derived mononuclear cells （MNC） were isolated by a Percoll density gradient and cultured in mesenchymal stem cell （MSC） maintenance medium. The homogenous layer of adherent cells exhibited a typical fibroblastlike morphology, a large expansive potential, and cell cycle characteristics including a subset of quiescent cells. In vitro differentiation assays showed the tripotential differentiation capacity of these cells toward adipogenic, osteogenic and chondrogenic lineages. Flow cytometry analyses and immunocytochemistry stain showed that placental MSC was a homogeneous cell population devoid of hematopoietic cells, which uniformly expressed CD29, CD44, CD73, CD105, CD166, laminin, fibronectin and vimentin while being negative for expression of CD31, CD34, CD45 and m-smooth muscle actin. Most importantly, immuno-phenotypic analyses demonstrated that these cells expressed class Ⅰ major histocompatibility complex （MHC-I）, but they did not express MHC-Ⅱ molecules. Additionally these cells could suppress umbilical cord blood （UCB） lymphocytes proliferation induced by cellular or nonspecific mitogenic stimuli. This strongly implies that they may have potential application in allograft transplantation. Since placenta and UCB are homogeneous, the MSC derived from human placenta can be transplanted combined with hematopoietic stem cells （HSC） from UCB to reduce the potential graft-versus-host disease （GVHD） in recipients.

Promoting human embryonic stem cell renewal or differentiation by modulating Wnt signal and culture conditions

We previously showed that Wnt3a could stimulate human embryonic stem （hES） cell proliferation and affect cell fate determination. In the absence of feeder cell--derived factors, hES cells cultured under a feeder-free condition survived and proliferated poorly. Adding recombinant Wnt3a in the absence of feeder cell derived-factors stimulated hES cell proliferation but also differentiation. In the present study, we further extended our analysis to other Wnt ligands such as Wntl and Wnt5a. While Wntl displayed a similar effect on hES cells as Wnt3a, Wnt5a had little effect in this system. Wnt3a and Wntl enhanced proliferation of undifferentiated hES cells when feeder-derived self-renewal factors and bFGF are also present. To explore the possibility to promote the proliferation of undifferentiated hES cells by activating the Wnt signaling, we overexpressed Wnt3a or Wntl gene in immortalized human adult fibroblast （HAFi） cells that are superior in supporting long-term growth of undifferentiated hES cells than primary mouse embryonic fibroblasts. HAFi cells with or without a Wnt tmnsgene can be propagated indefinitely. Over-expression of the Wnt3a gene significantly enhanced the ability of HAFi feeder cells to support the undifferentiated growth of 3 different hES cell lines we tested. Co-expression of three commonly-used drug selection genes in Wnt3a-overpressing HAFi cells further enabled us to select rare hES clones after stable transfection or transduction. These immortalized engineered feeder cells （W3R） that co-express growth-promoting genes such as Wnt3a and three drug selection genes should empower us to efficiently make genetic modified hES cell lines for basic and translational research.

Tissue engineering of blood vessels with endothelial cells differentiated from mouse embryonic stem cells

Endothelial cells (TEC_3 cells) derived from mouse embryonic stem (ES) cells were used as seed cells to construct blood vessels. Tissue engineered blood vessels were made by seeding 8 × 10~6 smooth muscle cells (SMCs) obtained from rabbit arteries onto a sheet of nonwoven polyglycolic acid (PGA) fibers, which was used as a biodegradable polymer scaffold. After being cultured in DMEM medium for 7 days in vitro, SMCs grew well on the PGA fibers, and the cell-PGA sheet was then wrapped around a silicon tube, and implanted subcutaneously into nude mice. After 6～8 weeks, the silicon tube was replaced with another silicon tube in smaller diameter, and then the TEC_3 cells (endothelial cells differentiated from mouse ES cells) were injected inside the engineered vessel tube as the test group. In the control group only culture medium was injected. Five days later, the engineered vessels were harvested for gross observation, histological and immunohistochemical analysis. The preliminary results demonstrated that the SMC-PGA construct could form a tubular structure in 6～8 weeks and PGA fibers were completely degraded. Histological and immunohistochemical analysis of the newly formed tissue revealed a typical blood vessel structure, including a lining of endothelial cells (ECs) on the lumimal surface and the presence of SMC and collagen in the wall. No EC lining was found in the tubes of control group. Therefore, the ECs differentiated from mouse ES cells can serve as seed cells for endothelium lining in tissue engineered blood vessels.

Shp2-mediated molecular signaling in control of embryonic stem cell self-renewal and differentiation

A key issue to be addressed in stem cell biology is the molecular signaling mechanism controlling embryonic stem （ES） cell pluripotency. Stem cell properties are dictated by specific transcription factors and epigenetic processes such as DNA methylation and chromatin remodeling. Several cytokines/growth factors have been identified as critical ES cell regulators. However, there is a gap in our knowledge of the intracellular signaling pathways linking extracellular signals to transcriptional regulation in ES cells. This short review discusses the physiological role of Shp2, a cytoplasmic tyro- sine phosphatase, in the molecular switch governing ES cell self-renewal versus differentiation. Shp2 promotes ES cell differentiation, mainly through bi-directional modulation of Erk and Stat3 pathways. Deletion of Shp2 in mouse ES cells results in more efficient self-renewal. This observation provides the impetus to develop Shp2 inhibitors for maintenance and amplification of ES cells in culture.

Thymic epithelial progenitor cells and thymus regeneration: an update

The thymus provides the essential microenvironment for T-cell development and maturation. Thymic epithelial cells （TECs）, which are composed of thymic cortical epithelial cells （cTECs） and thymic medullary epithelial cells （mTECs）, have been well documented to be critical for these tightly regulated processes. It has long been controversial whether the common progenitor cells of TECs could give rise to both cTECs and mTECs. Great progress has been made to characterize the common TEC progenitor cells in recent years. We herein discuss the sole origin paradigm with regard to TEC differentiation as well as these progenitor cells in thymus regeneration.

Increased apoptosis in third - trimester placental tissue from gestations complicat-ed by PIH

Objective: To investigate a possible role of apoptosis in the pathophysiologic mechanisms of PIH (pregnancy-induced hypertension syndrome).Methods: In this study, placental samples were obtained from 16 uncomplicated third-trimester pregnancies and from 16 cases of PIH.We used light microscopy, electron microscopy to identify apoptosis.Light microscopy was used to quantify their incidence of apoptosis.Electron microscopy was used to confirm the occurrence of apoptosis.Results: Apoptosis has been conclusively demonstrated within human third-trimester placental tissue.Medians and interquartile ranges of normal placenta (n=16) was 0.12% (0.08%-0.19%); Medians and interquartile ranges of PIH group (n=16) was 0.37% (0.15%-0.49%).Compared to normal placentas, the incidence of apoptosis was higher in placentas from gestations complicated by PIH (P<0.05, T'-test).Conclusion: Placental apoptosis increases significantly in PIH, and it may play a role in the pathophysiologic mechanisms of this syndrome.

Initiation of primary cell culture from amphioxus Branchiostoma belcheri tsingtauense

Amphioxus, a cephalochordate, is an important model fish for studies in evolution and comparative biology. A successful cell culture from amphioxus tissues in vitro would help understanding some basic issues. To determine the optimal culture conditions for proliferation of amphioxus cells, primary cultures were initiated from buccal cirri, tail, gill, gut and metapleural fold of amphioxus Branchiostoma belcheri tsingtauense. The media tested were L-15, F-12, M 199, MEM, DMEM, PRMI 1640 and LDF, each was supplemented with 20% fetal bovine serum. The optimal conditions include tail tissue cultured in L-15 or F-12 with supplement of 20% FBS and 1.5% NaCl at about 25℃.

Photoinduced directional domain sliding motion in peptide hydrogels promotes ectodermal differentiation of embryonic stem cells

Mechanical cues present in the stem cell niche resulting from intracellular processes or external force sources significantly affect the basic functions of stem cells such as self-renewal and differentiation.Creation of artificial cellular matrices exhibiting intrinsic mechanical cues generated by mechanical movements remains scarce.Herein,we reported on mechanically dynamic hydrogel matrices undergoing photo-induced directional domain sliding movement and their role in regulating embryonic stem cell(ESC)differentiation.The mechanically dynamic hydrogels were prepared via the self-assembly of an alternating hydrophilic and hydrophobic peptide with a photocaged cysteine residue.Upon light irradiation,the assemblies of the caged peptide were converted to non-equilibrated non-caged peptide bilayers that underwent the directional domain sliding motion induced by the thermodynamically favorable hydrophobic collapse transition.Culturing murine ESCs on the mechanically dynamic hydrogels resulted in biased differentiation toward the ectodermal lineage.We further showed that the mechanically dynamic hydrogels stimulated the translocation of a mechanotransduction protein Yes-associated protein(YAP)into the nucleus,implicating a potential mechanotransduction mechanism for the biased differentiation of ESCs.The finding of the biased ectodermal differentiation of ESCs induced by the mechanically dynamic hydrogels implies the great potency of the mechanically dynamic hydrogels as biomaterials for disease therapy and tissue regeneration in the future.