硒和B-27添加剂在神经干细胞存活与分化中的作用

目的 观察微量元素硒和神经细胞培养添加剂B-27对神经干细胞存活与分化的影响。方法 采用新生Wistar大鼠神经干细胞体外分离培养技术,应用盖玻片培养法和免疫细胞化学法来观察在无血清培养液中加入添加剂B-27和不含B-27时,硒对神经干细胞存活以及神经元分化标记蛋白β-微管蛋白、星形胶质细胞标记蛋白抗胶质细胞醋酸纤维蛋白（GFAP）和少突胶质细胞标记蛋白抗环核苷酸磷酸二酯酶（CNP酶）表达的影响。结果 在培养液中加入B-27添加剂同时加入硒时,神经干细胞能够存活并且分化成熟良好。在不含B-27添加剂同时也不含硒的培养液中神经干细胞不能够存活。在不含B-27添加剂而含有硒时,神经干细胞则能够存活并且能分化成神经元、星形胶质细胞和少突胶质细胞,各种细胞的形态典型。显微镜下计数发现神经干细胞在含硒的培养液中向神经胶质细胞方向分化比例较高。其中神经元分化β-微管蛋白阳性细胞每高倍视野为11．2个。胶质细胞分化方向GFAP阳性和CNP酶阳性细胞计数平均每高倍视野分别为16．1个和9．3个。结论 硒对于神经干细胞体外存活和分化是必需的营养成分。在不含B-27,但有硒存在时,神经干细胞能够存活并分化成熟。     

Adenovirus-mediated FasL gene transfer into human gastric carcinoma

AIM: To evaluate the possible value of FasL in gastric cancer gene therapy by investigating the effects of FasL expression on human gastric cancer cell line. METHODS: An adenoviral vector encoding the full-length human FasL cDNA was constructed and used to infect a human gastric cancer (SGC-7901) cell line. FasL expression was confirmed by X-gal staining, flow cytometric analysis and RT-PCR. The effect of FasL on cell proliferation was determined by clonogenic assay, cytotoxicity was detected by MTT assay, and cell viability was measured by trypan blue exclusion. The therapeutic efficiency of Ad-FasL in vivo was investigated with a xenograft tumor model in nude mice. RESULTS: SGC-7901 cells infected with Ad-FasL showed increased expression of FasL, resulting in significantly decreased cell growth and colony-forming activity when compared with control adenovirus-infected cells. The cytotoxicity of anti-Fas antibody (CH-11) in gastric cancer cells was stronger than that of ActD (91±8 vs60±5,P<0.01), and the cytotoxicity of Ad-FasL was stronger than that of CH-11 (60±5 vs50±2, P<0.05). In addition, G1-phase arrest (67.75±0.39 vs 58.03±2.16, P<0.05) and apoptosis were observed in Ad-FasL-infected SGC-7901 cells, and the growth of SGC-7901 xenografts in nude mice was retarded after intra-tumoral injection with Ad-FasL (54% vs 0%,P<0.0001). CONCLUSION: Infection of human gastric carcinoma cells with Ad-FasL induces apoptosis, indicating that this target gene might be of potential value in gene therapy for gastric cancer.     

Tissue-engineered vessel strengthens quickly under physiological deformation: application of a new perfusion bioreactor with machine vision

In order to develop a patent tissue-engineered blood vessel that grossly resembles native tissue, required culture times in most studies exceed 8 weeks. For the sake of shortening the maturation period of the constructs, we have used deformation as the basic index for mechanical environment control. A new bioreactor with a machine vision identifier was developed to accurately control the deformation of the construct during the perfusion process. Two groups of seeded constructs (n = 4 per group) were investigated in this study, with one group stimulated by a cyclic deformation of 10% and the other by a pulsatile pressure that gradually increased to 120 mm Hg (the control group). After 21 days of culture, the mechanical properties of the constructs were examined. The average burst strength and suture retention strength in the two groups were significantly different (t test, p < 0.05). For the experimental group, the average burst strength and suture retention strength were higher than those of the control group, by 31.6 and 23.4%, respectively. Specifically, the average burst strength of the constructs reached 1,402 mm Hg (close to that of the native vessel, i.e. 1,680 mm Hg) within a relatively short period of 21 days. In conclusion, deformation is an observable, controllable and very valuable index for mechanical environment control in vascular tissue engineering. It makes the control of mechanical stimuli more essential and experiments more comparable.     

体外琼脂培养人与小鼠骨髓粒系定向干细胞的比较

It has been shown that the muscular conditioned medium(MCM)is rich in colony stimulating factor.Its effect is species specific.The mouse MCM can be inactivated by ethyl ester.More than 70% colonies produced by mouse MCM are of loose diffusive type.On the contrary,the activity of human MCM is only slightly inhibited by ethyl ester and about 66%colonies formed by human MCM appear to be dense and compact.The doubling time for the multiplication of mouse bone marrow cells is 10.6 hours while that for human cells is 23.6 hours.     

Engrafted bone marrow-derived flk-(1+) mesenchymal stem cells regenerate skin tissue

Stem cell plasticity has created great interest because of its potential therapeutic application in degenerative or inherited diseases. Transplantation of bone marrow-derived stem cells was shown to give rise to cells of muscle, liver, nerve, endothelium, epithelium, and so on. But there are still disputes about stem cell plasticity, especially concerning the contribution of bone marrow-derived cells to skin cells. In this study, CM-DiI fluorescence-labeled Flk-(1+) bone marrow mesenchymal stem cells (bMSCs) of BALB/c mice (H-2Kd, white) were transplanted into lethally irradiated C57BL/6 mice (H-2Kb, black). By fluorescence tracing, we found that donor cells could migrate and take residency at the skin, which was confirmed by Y chromosome-specific PCR and Southern blot. The recipient mice grew white hairs about 40 days later and white hairs could spread over the body. Immunochemistry staining and RT-PCR demonstrated that skin tissue within the white hair regions was largely composed of donor-derived H-2Kd cells, including stem cells and committed cells. Furthermore, most skin cells cultured from white hair skin originated from the donor. Thus, our findings provide direct evidence that bone marrow-derived cells can give rise to functional skin cells and regenerate skin tissue. These may have important scientific implications in stem cell biology and transplantation therapy for skin tissue injury.     

经皮肾动脉成形术治疗肾动脉狭窄的现状

随着诊断手段和经皮介入治疗器械的进步,近10年来,经皮肾动脉成形术治疗肾动脉狭窄发展迅速,其适应证不断扩大,但什么样患者需要接受介入治疗、是否所有介入治疗均能改善血压和肾功能,目前尚存在一定争议。现在我们国内有许多心脏介入医师往往在冠状动脉造影术中做个“顺路”肾     

CCR2 expression by brain microvascular endothelial cells is critical for macrophage transendothelial migration in response to CCL2

While the expression of chemokine receptors by endothelial cells is now well established, little is known of the function of these receptors at this cellular locale. However, given that chemokines are instrumental in directing leukocytes to specific parenchymal sites, one possibility is that endothelial chemokine receptors play a role in the process of leukocyte extravasation. To test this hypothesis, we investigated the contribution of CCR2, the major cognate receptor for the chemokine CCL2 (formerly known as MCP-1), to CCL2-stimulated transendothelial migration of macrophages (m?) across cultured brain microvascular endothelial cells (BMEC). Specifically, we prepared both BMEC and m? from wild-type (WT) mice and mice deficient in CCR2; i.e., CCR2 (-/-), and compared the ability of WT and CCR2 (-/-) BMEC to support CCL2-stimulated transendothelial migration of WT and CCR2 (-/-) m?. In response to CCL2, WT m?, but not CCR2 (-/-) m?, were stimulated to migrate across WT BMEC, consistent with the recognized obligatory role for CCR2 in mediating CCL2-stimulated responses. Remarkably, however, neither WT nor CCR2 (-/-) m? were stimulated by CCL2 to migrate across CCR2 (-/-) BMEC. In contrast, both types of m? were able to migrate similarly across both types of BMEC in response to another chemokine--CCL3 (formerly known as MIP-1alpha)--which utilizes receptors other than CCR2. Lastly, CCL2-induced m? transendothelial migration was blocked by treatment of WT BMEC with pertussis toxin, suggesting that CCR2 is functionally coupled to the inhibitory G protein Galphai, much as it is in other cell types. These results highlight a heretofore-unrecognized role for endothelial CCR2 in mediating transendothelial migration.