CTLA-4-Tg/CD-28-KO Mice Exhibit Reduced T Cell Proliferation in vivo Compared to CD-28-KO Mice in a Graft-versus-host Disease Model

Activated T cells express inhibitory receptors such as CTLA-4 that can downregulate immune responses. Blockade of or genetic deficiency in CTLA-4 can result in autoimmunity. Therefore, strategies to increase the inhibitory function of CTLA-4 may be attractive in settings of undesirable T cell responses such as autoimmunity or transplant rejection. We have tested the hypothesis that transgenic constitutive expression of CTLA-4 can further attenuate immune responses when compared with normal inducible expression. Our results indicate that transgenic expression of CTLA-4 in mouse T cells (CTLA-4-Tg T cells) results in reduced cell cycle progression and increased apoptosis of TCR-stimulated T cells. CTLA-4-Tg T cells display reduced T cell proliferation in an in vivo model of graft versus host disease (GVHD). These results further our understanding of how CTLA-4 can be manipulated to inhibit immune responses and may help development of new therapeutic strategies for clinical settings of autoimmunity and transplantation.     

影响乙型肝炎病毒进入过程的相关因素分析

HBV属于嗜肝DNA病毒家族,具有狭窄的宿主范围及肝组织亲嗜性.大量试验数据显示,HBV L蛋白的PreS1区直接参与病毒和肝细胞的黏附.PreS1区N末端的豆蔻酰基化修饰对HBV感染也起着至关重要的作用.近年来研究证实,S区上富含半胱氨酸的抗原决定簇环是参与HBV感染的另一重要因素.HBV与肝细胞的黏附涉及到一些细胞蛋白,但尚无确切的证据证实它们在HBV感染中所起的具体作用.HBV的进入过程为抗病毒药物提供了新的治疗靶点,其研究是HBV领域的热点.此文就参与HBV进入的病毒及细胞相关因素作了综述.     

Physiological and anthropometric characteristics of junior cyclists of different specialties and performance levels

This study analyzes the anthropometric and physiological characteristics of junior cyclists within different cycling specialties and different performance levels. One hundred and thirty‐two junior riders (16.8 ± 0.6 years, 177 ± 6 cm, 66.3 ± 6.7 kg) were tested for anthropometric, aerobic and anaerobic parameters. Cyclists were classified within specialties [uphill (UH) flat terrain (FT) all terrain (AT) and sprint (SP)] and performance levels, based on a seasonal ranking [low level (LL) medium level (ML) and high level (HL)]. The results of the two‐way analysis of variance showed that FT and SP have greater body dimensions than UH and AT (P<0.001). Concerning the relative aerobic parameters, AT and UH have higher values (P<0.001) than FT and SP [maximal oxygen uptake (VO_2max): 69.4 ± 3.6, 67.5 ± 5.0, 62.8 ± 4.5 and 61.9 ± 4.1 mL/kg/min, respectively] while absolute parameters resulted higher for FT and AT (P≤0.008). The relative power produced in the 5 s test was higher (P<0.001) for AT and SP than FT and UH (16.7 ± 1.1, 16.6 ± 0.6, 14.9 ± 1.7 and 14.4 ± 1.7 W/kg, respectively). Concerning the performance level, only the age and the aerobic parameters resulted differently within levels (VO_2max: HL=67.3 ± 4.9, ML=65.5 ± 5.1 and LL=63.3 ± 5.2 mL/kg/min), with the highest values for HL (P≤0.007). In conclusion, juniors are specialized in the same way as professional cyclists and the aerobic characteristics are confirmed as significant in the performance level assessment.     

Increased Blood Oxygen Affinity and Physical Work Capacity in Man

Influence of altered blood oxygen affinity on work performance in man was investigated. Increased in vitro blood oxygen affinity was achieved in vivo by partial DPG depletion induced by 70 hours of acidosis followed by acute restoration of acid-base balance by intravenous NaHCO₃. Work performance tests with determination of submaximal and maximal oxygen uptake were performed at the two different DPG levels. Submaximal and maximal oxygen uptake remained unchanged when DPG decreased from 0.80 to 0.58 mol/mol Hb and P_{50 (7.4. BE=0)} (oxygen tension at half saturation of hemoglobin) decreased from 26.4 to 24.0 mm Hg. Thus a small increase of in vitro whole blood oxygen affinity does not impair work performance in man.     

^18F—FDGPET／CT显像在鼻咽癌中的应用

阐述^18F—FDGPET／CT显像对鼻咽痛诊断、分期、疗效评价、放射性脑病以及在放疗治疗设计中的价值,并指出需要开发更为特异示踪剂以提高诊断的准确性,同时需要开展多中心研究,明确SUV值与放疗靶区勾画的关系。     

超声引导肝恶性肿瘤射频消融术与手术切除对细胞免疫影响的对比研究

目的探讨超声引导下射频消融术与手术切除术对肝癌患者外周血T淋巴细胞亚群的影响。方法应用流式细胞仪检测,30例以射频消融为治疗方式和30例以手术切除为治疗方式的原发性肝癌患者的术前、术后T淋巴细胞亚群的变化。结果射频组术后10d和20d外周血中CD3+、CD4+、CD4+/CD8+水平均明显高于术前水平,CD8+明显低于术前,差异均有统计学意义(均P0.05),且持续时间较长。手术组外周血中CD3+、CD4+、CD4+/CD8+水平明显低于术前水平,CD8+明显高于术前,差异均有统计学意义(P0.05)。射频组术后10 d和20 d外周血中CD3+、CD4+、CD4+/CD8+均明显高于手术组,CD8+明显低于手术组,差异均有统计学意义(均P0.05)。结论射频消融治疗肝癌患者细胞免疫功能增强,手术治疗则免疫细胞功能下降。射频消融在保护与改善细胞免疫功能方面强于手术治疗方法。     

苯中毒再生障碍性贫血患者骨髓细胞免疫功能和Fas、CD34抗原变化

目的　探讨细胞免疫功能、Fas和CD3 4抗原与苯中毒再生障碍性贫血发生、发展及转归的关系。方法　用流式细胞仪检测2 4例苯中毒再障(BPAA)和16例无苯制剂接触史的再障(AA)患者治疗前后骨髓单个核细胞Fas、CD3 4的表达率和T细胞亚群变化。结果　苯中毒再生障碍性贫血和再障患者骨髓单个核细胞Fas表达率显著增高(P <0 . 0 0 1) ,CD3 4阳性率明显降低(P <0 . 0 0 1) ;CD3 + CD8+ T淋巴细胞明显升高(P <0 . 0 5 ) ,CD4+ /CD8+ 比值明显降低(P <0 . 0 0 1) ;治疗缓解后Fas、CD3 4阳性率、CD3 + CD8+ T淋巴细胞和CD4+ /CD8+ 比值趋于正常(P >0 . 0 5 )。但在AA组Fas、CD3 4阳性率和CD4+ /CD8+ 比值较正常对照组差异仍有显著性。两组再障患者之间比较差异无显著性。结论　细胞免疫功能紊乱、Fas抗原的异常表达和CD3 4+ 干/祖细胞损伤,可能与苯中毒再生障碍性贫血病理发病机制有关,用环孢霉素A治疗可能有效。     

马钱子碱固体脂质纳米粒的细胞毒性及细胞摄取试验

目的:研究马钱子碱固体脂质纳米粒(brucine-loaded solid lipid nanoparticles,B-SLN)对Hep G2的细胞毒性和细胞摄取情况。方法:采用四甲基偶氮唑盐比色法(MTT)检测B-SLN对Hep G2细胞的毒性,利用荧光显微镜定性观察细胞摄取情况,运用流式细胞仪定量检测不同条件下的细胞摄取情况。结果:马钱子碱组和B-SLN组对Hep G2细胞增殖具有抑制作用,且抑制率随时间延长和药物质量浓度增加而上升。马钱子碱组48,72 h的半抑制浓度(IC_(50))分别为208.5,78.5 mg·L~(-1),B-SLN组48,72 h的IC50分别为563.3,114.9 mg·L~(-1);药物质量浓度在125~500 mg·L~(-1)时,随药物质量浓度的增加,细胞摄取量由50.2%增加到71.2%;温度在4℃和37℃条件下,细胞摄取量由43%增加到55.2%;摄取时间在30~240 min时,随孵育时间的增加,细胞摄取量由9.7%增加到56.4%。结论:SLN给药系统能显著提高马钱子碱对抗癌细胞的活性,且B-SLN具有增加药物被细胞摄取的能力。     

根皮素对rBMECs摄取人参皂苷Rb1的影响

 目的 以原代培养的大鼠脑微血管内皮细胞为模型,研究根皮素对大鼠脑微血管内皮细胞摄取人参皂苷Rb1的影响。方法 实验分为2组,人参皂苷Rb1对照组和根皮素干预组。运用LC-MS/MS测定大鼠脑微血管内皮细胞对人参皂苷Rb1的摄取量,BCA法测细胞蛋白浓度。结果 根皮素干预组大鼠脑微血管内皮细胞对人参皂苷Rb1的摄取量显著低于人参皂苷Rb1对照组(P<0.05)。结论 根皮素可显著抑制大鼠脑微血管内皮细胞对人参皂苷Rb1的摄取。