小鼠S180移植瘤血管生成作用及其调节机制的研究

目的：观察肉瘤180(S180)移植瘤发展过程中血管生成及血管生成调节因子的变化,并对其调节机制进行探讨。 方法： 利用Km小鼠的S180移植瘤模型，采用FⅧ因子免疫组化染色检测肿瘤血管生成，ELISA和EIA法检测荷瘤鼠肿瘤组织和血浆中血管内皮生长因子（VEGF）和内皮抑制素（endostatin）水平，采用多元回归分析肿瘤组织微血管计数、血管形态与瘤重变化的关系。 结果： 随着荷瘤时间延长，肿瘤组织内微血管计数，瘤内血管相对总量增加，血管的相对面积增大（P<0.05）；肿瘤组织匀浆中VEGF水平在荷瘤10 d、15 d均显著高于5 d组（P<0.05）；endostatin在肿瘤匀浆和血浆中均在荷瘤15 d达到最高（P<0.05）；V/E比值无显著变化；微血管计数、血管相对总面积与瘤重变化有相关性（P<0.01）。 结论： S180移植瘤病期发展中微血管数目增加，血管口径增大，且与瘤重变化呈正相关；肿瘤发展过程中肿瘤局部血管生成正调节因子逐渐增加，促进血管生成；肿瘤局部血管生成调节因子处于相对的平衡。     

青蒿琥酯抑制人食管癌Eca-109细胞系的CDC25A表达

目的观察青蒿琥酯（artesunate，Art）对人食管癌Eca-109细胞系的抑瘤作用，并进一步探讨ATt诱导肿瘤细胞周期阻滞与CDC25A、TGF-β表达的关系。方法体外培养人食管癌Eca-109细胞系及正常人外周血单个核细胞（hPBMC），利用MTT法测定细胞增殖；采用流式细胞术（FCM）测定细胞周期；应用RT．PCR方法检测CDC25AmRNA表达，应用Western blot方法检测蛋白表达。结果Art能显著抑制Eca-109细胞的增殖，ICS0为（68．80±0．76）μmol／L，而对hPBMC的增殖则没有明显抑制作用。低浓度Art可将细胞阻滞于G0／G1期，S期细胞显著减少，当浓度达到100μmol／L时，细胞阻滞于G2／M期。Art可显著抑制Eca-109细胞CDC25AmRNA及蛋白表达，同时显著上调TGF-β的蛋白表达水平。结论Art可抑制肿瘤细胞生长，上调TGF-β表达，抑制CDC25A表达。     

ERK1／2-STAT3通路在H2O2预处理导致的适应性细胞保护中的作用

目的:探讨ERKI/2一STAT3通路在H2O2预处理导致的适应性细胞保护中的作用.方法:在PCI2细胞建立H2O2预处理对抗氧化应激(300 pmot/L H202)损伤细胞的模型.应用Hoechst33258核染色法观察细胞调亡的形态学改变;应用碘化丙啶(P1)染色流式细胞术检测细胞凋亡率;免疫印记法(Western blotting)测定P-ERKI／2和P-STAT3的表达水平.结果:100μmol/L H2O2预处理PCI2细胞90 rain可明显抑制300μmol/LH2O2作用12 h引起的细胞凋亡,并激活ERKl/2和STAT3;ERKI/2抑制剂U0126和JAK2抑制剂AG一490(10μmol/L)均可明显地阻断H2O2预处理引起的细胞保护作用;U0126(10μmol/L)亦能明显地抑制H2O2预处理对STAT3的上调作用.结论:H202预处理能激活PCI2细胞的ERKl/2-STAT3信号转导旁路,这可能是预处理的细胞保护机制之一.     

湖南汉族人群HLA-DP、-DQ位点等位基因多态性与鼻咽癌的相关性

目的 探讨湖南汉族人群HLA—DP、HLA—DQ位点等位基因多态性与鼻咽癌遗传易感性之间的关系。方法 应用聚合酶链反应—特异性寡核苷酸探针基因分型技术对87例湖南汉族鼻咽癌患者与91名健康对照作HLA—DPAl、—DPBl、—DQAl及—DQBl的基因分型，采用x^2检验比较两组各位点等位基因频率，单倍型频率分布的差异。结果 发现鼻咽癌组DPAl*0201、DPBl*1901、DQAl*0201较对照组明显降低，DPBl*0402、DQAl*0101较对照组明显升高；单倍型DPAl*0201—DPBl*1401及DQAl*0201—DQBl*0201较对照明显降低；但P值经Bonferroni校正后，差异均无显著性(Pc＞0．05)。结论 湖南汉族人群HLA—DP和—DQ位点与鼻咽癌无明显相关，与以往用受累同胞对方法在鼻咽癌家系中未能证实鼻咽癌易感基因与HLA—DP和—DQ位点连锁的结果一致。     

Targeting of CD45 protein tyrosine phosphatase activity to lipid microdomains on the T cell surface inhibits TCR signaling

CD45, a transmembrane protein tyrosine phosphatase (PTP), can either positively or negatively regulate Src-family protein tyrosine kinase (PTK) activity in vivo. It is proposed that TCR-initiated signaling requires the segregation of PTP activities from the engaged TCR, based upon the differential membrane compartmentalization on the T cell surface. To test the importance of CD45 exclusion from lipid microdomains for proper TCR signaling, a chimeric molecule was generated by fusing the CD45 cytoplasmic region, which contains the PTP domains, to the amino-terminal 12 amino acids of Lck, which target Lck to lipid microdomains. Using 3A9 T lymphocyte hybridoma (3A9H) cells whose TCR recognizes hen egg-white lysozyme (HEL), Lck-CD45 expression resulted in its targeting to lipid microdomains. The 3A9H cells expressing Lck-CD45 were reduced in their responses to HEL or co-cross-linking of CD3 and CD4, as assessed by IL-2 production and Ca(2+) mobilization. Src-family PTK activity associated with lipid microdomains was also decreased. These results suggest that the segregation of CD45 from proximal TCR signaling components is necessary for TCR signaling and that the targeting of CD45 PTP activity to lipid microdomains on the T cell surface results in decreased sensitivity of TCR-mediated signaling.     

Induction of β-family chemokines mRNA in human embryonic astrocytes by inflammatory cytokines

The cellular infiltration found during CNS inflammation consists of monocytes and activated T cells, suggesting the presence of cell-specific chemotactic signals during inflammatory responses. Astrocyte chemokine expression might contribute to site-specific leukocyte infiltration within the CNS. To investigate the factors that regulate astrocyte chemokine expression, we examined the ability of human fetal astrocytes to induce -family chemokine mRNA. Astrocyte-derived monocyte chemoattractant protein-1 (MCP-1), RANTES, macrophage inflammatory protein-1 (MIP-1), and MIP-1 mRNA were easily induced by lipopolysaccharide and/or the proinflammatory cytokines (IFN and/or TNF-), respectively. Addition of both IFN and TNF- together did not lead to an additive effect but resulted in the inhibition of MCP-1 and MIP-1 mRNA expression, indicating that interaction between chemokines and cytokines may play a key role in regulating the local immune response of resident and infiltrating cells at the site of lesion. Interestingly, ultraviolet light-inactivated measles virus, but not cytomegalovirus, strongly induced expression of MCP-1, RANTES, MIP-1, and MIP-1 mRNA in human embryonic astrocytes, especially MCP-1 and MIP-1. An association occurs between the -family chemokine expression in astrocytes and inflammatory factors/virus, suggesting a possible role for -family chemokines in the pathogenesis of CNS inflammatory disease.     

Reversible Photo‐Mechanical Switching Behavior of Azobenzene‐Containing Semi‐Interpenetrating Network under UV and Visible Light Irradiation

Summary: Light‐induced reversible changes in elasticity of semi‐interpenetrating network (semi‐IPN) films bearing azobenzene moieties were achieved under both ultraviolet (UV) and visible light irradiation. The semi‐IPN film was prepared by a cationic copolymerization of azobenzene‐containing vinyl ethers in a linear polycarbonate (PC) film as a matrix. When the irradiation was switched on and off, the semi‐IPN film showed rapid reversible deformation with the same behavior occurring over a range of wavelengths, including both the UV and visible regions. The observed reversible deformation of the film was attributed to the decrease in the film's elasticity, which was assumed to be caused by the frequent trans‐cis cycling isomerization of azobenzene moieties taking place during the UV and visible light irradiation. This cycling makes it difficult for the azobenzene groups to aggregate, thus hindering their ability to function as pseudo‐crosslinking points.

     

3D-printed prostheses for large bone defect reconstruction following bone tumor surgery北大核心

BACKGROUND: Tumor segment resection is one of the standard methods for the treatment of bone tumors. However, the reconstruction of bone defects atumor resection faces many challenges. A growing number of researchers are focusing on 3D-printed prostheses for bone defect repair and reconstruction following bone tumor surgery. OBJECTIVE: To explore the feasibility of 3D-printed prostheses in the reconstruction of large bone defect following bone tumor surgery and to evaluate the postoperative outcomes. METHODS: Retrospective analysis of clinical data of 24 patients [19 males and 5 females, age 23.8 (6-61) years] who underwent bone tumor resection and 3D-printed prosthesis implantation in the Department of Bone Oncology, the First Affiliated Hospital of Xinjiang Medical University from December 2020 to September 2021 was conducted. There were 7 cases with distal femur tumor, 5 with pelvis tumor, 4 with proximal tibia tumor, 3 with middle femur tumor, 1 with distal tibia tumor, 1 with proximal humerus tumor, 1 with middle humerus tumor, 1 with scapula tumor, 1 with ulna tumor, and 22 cases with primary tumors (13 osteosarcoma, 4 Ewing sarcoma, 2 giant cell tumor of bone, 1 chondroblastoma, 1 chondrosarcoma, and 1 osteoblastoma), 2 metastatic carcinoma. Preoperative and postoperative imaging data were recorded and neoadjuvant chemotherapy was administered in 17 cases before surgery. The Musculoskeletal Tumour Society score was used to assess limb function before surgery and 6 months after surgery, and pain was assessed by the Visual Analog Scale, as well as the complications were recorded. RESULTS AND CONCLUSION: (1) All patients undergoing resection of the tumor segment and 3D-printed prosthesis implantation for the reconstruction of the bone defect were followed for 6-49 months, and the results showed that the length of osteotomy was (18.2 ± 7.3) cm and an average intraoperative bleeding volume was 740 (100-3 000) mL. (2) Two patients died of systemic metastasis, the remaining 22 had no pulmonary metastasis or recurrence during the follow-up period, and 1 patient developed aseptic loosening of the prosthesis at 25 months postoperatively. (3) The Musculoskeletal Tumour Society scores were significantly increased, while Visual Analog Scale scores were significantly decreased (P < 0.05) at 6 months postoperatively. (4) The Musculoskeletal Tumor Society score was rated excellent in all 22 patients at the final follow-up. (5) These results suggest that 3D-printed prosthesis is suitable for the reconstruction of large bone defects caused by bone tumor resection. Patients have good postoperative function and few complications. However, further investigations are needed to explore long-term follow-up results. © 2023, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

雄激素应答元件陷阱DNA抑制PSA基因启动子的作用并诱导LNCaP细胞凋亡(英)

目的：研究雄激素应答元件陷阱DNA（ARE decoy）对前列腺特异抗原（PSA）基因启动子的抑制作用及其对前列腺癌细胞LNCaP细胞生长活性的影响，为前列腺癌的基因治疗寻求新的策略。 方法:联合运用报告基因和陷阱DNA策略，构建含PSA基因5’侧启动子区640 bp DNA的荧光素酶表达载体pGL3-PSA， ARE陷阱DNA共转染前列腺癌细胞株PC3-M。应用双荧光素酶测定系统，检测荧光素酶的表达活性。然后，应用2 mg/L ARE decoy转染LNCaP细胞，通过相差显微镜观察细胞超微结构变化，MTT比色法检测细胞生长活性，DNA ladder和流式细胞技术（FCM）检测细胞凋亡以研究ARE decoy DNA对前列腺癌细胞LNCaP细胞生长活性的影响。同时提取LNCaP细胞核蛋白，应用电泳迁移率变动分析(EMSA)检测ARE decoy DNA与雄激素受体的特异结合。结果:ARE decoy DNA显著抑制报告基因荧光素酶的表达，抑制率可达95%。EMSA显示ARE decoy DNA能特异与核蛋白中雄激素受体结合。LNCaP细胞转染ARE decoy DNA后，镜下观察部分细胞出现凋亡形态学的改变，细胞体外生长受到抑制，染色体DNA凝胶电泳可见明显梯形条带。转染48h的凋亡率为22.4%。 结论:实验表明ARE decoy DNA能竞争结合雄激素受体(AR)，阻断AR的作用而诱导LNCaP细胞凋亡，有可能为前列腺肿瘤的治疗提供新的策略。     

TLR2和TLR4在原发性肝癌中的表达

目的：本研究通过检测原发性肝癌Toll样受体2（TLR2）和Toll样受体4（TLR4）的表达，分析其与临床病理生理因素的关系，探讨TLR2，TLR4在原发性肝癌疾病过程中的可能作用。方法：采用免疫组化法和实时荧光定量PCR分别在蛋白水平及mRNA水平检测原发性肝癌组织和配对癌旁组织TLR2、TLR4的表达。结果：原发性肝癌组织在蛋白水平和mRNA水平TLR2和TLR4的表达均明显低于癌旁组织（P<0.01）。但免疫组化结果显示不论是肝癌组织还是癌旁组织，TLR2和TLR4的表达均明显高于正常肝组织（P<0.01，P<0.05），有门静脉分支癌栓的患者癌组织TLR4的表达强度低于无门静脉分支癌栓的患者（P<0.05）。结论：肝癌组织TLR2和TLR4的表达与癌旁组织相比受到相对抑制，但高于正常肝组织，TLR2和TLR4信号途径可能参与了原发性肝癌的病理过程。