Human/mouse cross-reactive anti-VEGF receptor 2 recombinant antibodies selected from an immune b9 allotype rabbit antibody library

Vascular endothelial growth factor (VEGF) and its receptors have been implicated in promoting solid tumor growth and metastasis via stimulating tumor-associated angiogenesis. Models of murine tumor angiogenesis and receptor-specific antibodies are required to evaluate roles of VEGF receptors in mouse models of human cancer. Human VEGFR2 (also known as KDR) and murine VEGFR2 (or Flk-1) share 85% amino acid sequence identity in their extracellular domain. We describe here the development of antibodies that cross-react with mouse and human VEGFR2. High-affinity, species cross-reactive, Fabs specific for KDR/Flk-1 were selected from an antibody phage display library generated from an immunized rabbit of b9 allotype. The selected chimeric rabbit/human Fabs were found to bind to purified KDR and Flk-1 with nanomolar affinity. Three of the selected Fabs detected KDR expression on human endothelial cells as well as Flk-1 on murine endothelial cells. The availability of anti-VEGFR2 Fab with species cross-reactivity will help to decipher the functional role of KDR/Flk-1 in tumor biology as well as facilitate the preclinical evaluation of the suitability of KDR/Flk-1 for drug targeting. This report underscores our earlier finding that b9 rabbits are excellent sources for high-affinity cross-reactive antibodies with therapeutic potential.     

犬自体肺组织瓣修补食管壁部分缺损的可行性

目的:分析犬自体肺组织瓣修补食管壁部分缺损的可行性。方法:实验于2003-01/2004-11在中国医科大学附属第二医院动物实验室完成。选用健康成年杂种犬20只,按随机数字表法分为2组,即支架组和无支架组,每组10只。20只实验犬经右胸第5肋间进胸,于胸内中段食管处胸内食管侧壁制成长4cm,环1/2~2/3周径全层缺损。于相应部位选择适当的肺组织,制成带蒂类舌状肺组织瓣。两组均将肺组织瓣覆盖并缝合固定于食管缺损处,支架组于食管缺损内衬自扩性记忆合金支架(管腔直径2.0cm、长6.0cm)并固定。术后抗炎及营养支持治疗。观察实验犬术后情况,并于术后2,4,6,8,10和12周定期处死实验犬行组织学观察。结果:无支架组实验犬存活7只,其中1只犬存活>24个月;支架组存活6只。①实验犬术后一般情况:存活犬于术后均能正常经口进食,早期有进食后呕吐,再吃下呕吐食物的现象,以支架组明显。②组织学观察结果:术后2周,无支架组均可见替代物表面有胶原及炎性渗出物,边缘见1~2层鳞状上皮细胞;支架组除有无支架组基本表现外,可见支架固定良好,光镜下见网架压迫处有较多中性粒细胞浸润。4~6周,两组均可见替代物表面有新生的3~5层复层鳞状上皮细胞;支架组见支架已基本陷入黏膜层内。8~10周,两组均可见管腔表面有6~8层新生复层鳞状上皮细胞;支架组网架边缘瘢痕组织增生,支架完全被包裹,炎症较重的局部有细胞爬行中断现象或新生细胞层数较薄,多为一两层。结论:应用自体肺组织瓣修补食管壁部分缺损是可行的,但支架组支架对食管修补处组织刺激大,炎性反应重,瘢痕重,因此如何选择合适的支撑物是今后替代节段性食管缺损面临的重要问题。     

食欲素和食欲素受体与运动

目的:食欲素是一种重要的神经肽,通过了解食欲素的相关作用及其表达的调节因素等,可以为肥胖的发生机制及其防治工作,以及在运动中的研究开辟新的途径。资料来源:应用计算机检索1998/2006Medline的相关文章,检索词"orexin""hypocretin",并限定文章语言种类为英文。同时计算机检索1998/2006中国期刊全文数据库(http://www.cnki.net)的相关文章,检索项"关键词",检索词"食欲素""食欲肽""增食因子""胖素""阿立新素",限定文章语言种类为中文。共检索到200余篇文献。资料选择:对资料进行初审,纳入标准:①食欲素及其受体研究。②影响食欲素表达因素的研究。③食欲素与肥胖关系的研究。④食欲素与运动行为关系的研究。排除标准:重复性研究。资料提炼:共收集到56篇相关文献,中文文献均为全文,大部分外文文献为全文,其他为摘要。在这些文献中18篇为重复或类似的同一研究,38篇文献纳入分析。资料综合:食欲素是orphanG蛋白质共轭受体的配体,是下丘脑重要的神经肽。可分为食欲素A和食欲素B两种,它们来源于同一前体,其神经纤维贯穿脑和脊髓。食欲素受体分为OX1R和OX2R两型,OX1RmRNA和OX2RmRNA在脑内的分布不同。食欲素有调节摄食和能量平衡、调节睡眠觉醒状态、调节饮水等功能;其表达量受睡眠、营养状况、环境、性别等因素的影响。国内对食欲素的研究不多,主要是肥胖、低氧以及低糖状态对食欲素影响的研究;国外可见通过行为干预对食欲素的研究,以及其他因子对食欲素的影响。结论:食欲素作为一种重要的神经肽,除具有调节食欲和平衡能量的作用外,还具有保持觉醒,参与免疫应答等功能;食欲素抗体或受体拮抗剂还可能治疗肥胖、糖尿病等能量代谢失衡性疾病。但国内外对食欲素在运动训练及减肥中的相关研究还较少。     

同型半胱氨酸对大鼠血管平滑肌细胞增殖及胶原生成的影响

目的:观察同型半胱氨酸的浓度对Ⅰ,Ⅲ,Ⅳ和Ⅵ型胶原的产生以及大鼠血管平滑肌细胞增殖效应的影响。方法:实验于2005-02/2006-04在瑞金医院心内科实验室完成。①采用组织块贴壁法原代培养大鼠胸主动脉平滑肌细胞,用不同浓度的同型半胱氨酸(0.025,0.05,0.1,0.2,0.5,1.0,1.5,2.0,3.0,5.0 mmol/L)刺激大鼠血管平滑肌细胞,并设对照孔(未加同型半胱氨酸)和空白孔(未加细胞)作对照。②分别作用12,24,48,72h,以四甲基偶氮唑盐法检测同型半胱氨酸对平滑肌细胞的活性细胞数量及细胞增殖情况;以5溴-2脱氧尿苷法检测同型半胱氨酸对大鼠血管平滑肌细胞DNA合成的作用;流式细胞仪观察细胞周期的变化;酶联免疫法测定胶原的含量。结果:①细胞增殖情况:在0.025,0.05 mmol/L的同型半胱氨酸浓度刺激下,12～48h血管平滑肌细胞增殖增加明显。②细胞DNA合成:与四甲基偶氮唑盐结果类似,24～48h时,在浓度为0.025,0.05 mmol/L的同型半胱氨酸刺激下细胞合成DNA增加(24h:432±33,774±52;48h:582±32,816±62),其促增殖作用增强(P<0.05);随着浓度的增加,大鼠血管平滑肌细胞合成DNA开始下降,至5 mmol/L浓度时最低。③细胞周期的变化:24h时在浓度为0.025,0.05 mmol/L的同型半胱氨酸刺激下增殖的细胞S期的百分含量较对照组和同型半胱氨酸其他浓度组明显增加。④胶原的含量:细胞的Ⅰ型和Ⅳ型胶原分泌随着同型半胱氨酸浓度的升高呈现剂量依赖性的增高模式。Ⅲ型胶原有轻度的升高,无统计学上意义。高浓度的同型半胱氨酸会减少Ⅵ型胶原的分泌,并呈剂量依赖性(r2=0.41;P<0.001)。结论:较低浓度的同型半胱氨酸刺激大鼠血管平滑肌细胞的增殖加速;并可能通过改变纤维斑块中的胶原构成类型导致了斑块的不稳定性和易损性,最终加速了粥样斑块的发生和发展。     

运动疲劳大鼠能量代谢与红景天苷的影响

目的:已有研究表明,红景天具有抗缺氧、抗疲劳、抗血乳酸含量增加的作用。实验观察红景天苷对运动疲劳大鼠能量代谢的影响。方法:实验于2006-11/12在哈尔滨商业大学药物研究所药理实验室完成。①实验材料:高山红景天,红景天苷含量为3.065%;清洁级成年雄性SD大鼠40只,体质量160～180g。②实验分组:将大鼠随机分为4组(10只/组):即空白对照组、低、中、高剂量组。③实验过程:经口灌胃,空白对照组给予生理盐水,低、中、高剂量组分别给予红景天苷100,200,300mg/kg,连续灌胃14d。末次灌胃30min后,在大鼠尾根部负重5%体质量的铅皮,进行力竭性游泳。④实验评估:比较对照组与给药组大鼠游泳存活时间的长短;观察力竭游泳后各组大鼠血乳酸、血清尿素氮、血清肌酸激酶和肝糖元的变化。结果:每组取8只,共32只进入结果分析。①给药组大鼠游泳存活时间较对照组明显延长,差异有非常显著性意义(P<0.01),且高剂量组大鼠游泳存活时间最长。②与对照组相比,给药组对大鼠运动后的血乳酸、血清尿素氮、血清肌酸激酶有降低作用(P<0.05,P<0.01),肝糖元含量有所增加(P<0.01)。结论:红景天苷可以改善大鼠运动后的整体状况,可以通过调节能量代谢平衡提高大鼠的运动能力,有一定的抗疲劳作用。     

Comparison of characteristics of outpatients with 2009 H1N1 pandemic and seasonal influenza

Background: The latest influenza pandemic intensified the interest in this infection. Objective: We aimed to compare the characteristics of outpatients with seasonal and pandemic influenza. Methods: We retrospectively reviewed data regarding outpatients who sought medical advice from a network of physicians performing house‐call visits at the area of Attica, Greece, and who underwent a direct influenza test during the period of seasonal influenza (1/1/2009–1/5/2009) and 2009 H1N1 pandemic influenza period (17/5/2009–15/4/2010). Results: A total of 195 and 1317 patients had a direct influenza test during the seasonal and pandemic influenza period, respectively; 50.7% and 32% of these patients had a positive test result for influenza, respectively. Viral culture or polymerase chain reaction (PCR) were not implemented. Patients found positive for influenza during the pandemic period, compared with those evaluated during the seasonal period, were younger (mean age ± SD: 33 ± 17.2 vs. 38.2 ± 19.2, p = 0.008), more likely to have no comorbidity (62.9% vs. 45.5%, p = 0.002), had milder clinical manifestations, and were treated with more antibiotics (38.3% vs. 9.9%, p < 0.001). However, patients found positive during the seasonal period were treated with more antivirals (oseltamivir: 69.1% vs. 85.7%, p = 0.006). No difference was observed regarding the need for immediate hospitalisation. These findings were consistent in the complementary analysis involving patients tested for influenza during the compared periods. Conclusion: Despite the methodological limitations, our findings suggest that patients with pandemic influenza were younger, had milder clinical manifestations and were less likely to have any kind of comorbidity compared with patients with seasonal influenza.     

Multi-center transferability of a breath-hold T2 technique for myocardial iron assessment

Background

Cardiac iron overload is the leading cause of death in thalassemia major and is usually assessed using myocardial T2* measurements. Recently a cardiovascular magnetic resonance (CMR) breath-hold T2 sequence has been developed as a possible alternative. This cardiac T2 technique has good interstudy reproducibility, but its transferability to different centres has not yet been investigated.

Methods and Results

The breath-hold black blood spin echo T2 sequence was installed and validated on 1.5T Siemens MR scanners at 4 different centres across the world. Using this sequence, 5–10 thalassemia patients from each centre were scanned twice locally within a week for local interstudy reproducibility (n = 34) and all were rescanned within one month at the standardization centre in London (intersite reproducibility). The local interstudy reproducibility (coefficient of variance) and mean difference were 4.4% and -0.06 ms. The intersite reproducibility and mean difference between scanners were 5.2% and -0.07 ms.

Conclusion

The breath-hold myocardial T2 technique is transferable between Siemens scanners with good intersite and local interstudy reproducibility. This technique may have value in the diagnosis and management of patients with iron overload conditions such as thalassemia.