Biomimetic surface modification of poly(L-lactic acid) with chitosan and its effects on articular chondrocytes in vitro

The objective of this study was to investigate the efficiency of two treatments for poly(L-lactic acid) (PLLA) surface modification with chitosan, via entrapment and coupling by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide. The properties of original PLLA films, chitosan-entrapped and coupled PLLA films were investigated by water contact angle measurement and electron spectroscopy for chemical analysis (ESCA). The contact angle indicated the change in hydrophilicity and the ESCA data suggested that the modified PLLA films became enriched with nitrogen atoms. The cytocompatibility of modified PLLA films might be improved. Therefore, the attachment and proliferation of bovine articular chondrocyte seeded on modified PLLA films and control one were examined. A whole cell enzyme-linked immunosorbent assay (Cell ELISA) that detects the BrdU incorporation during DNA synthesis and collagen type II secretion was applied to evaluate the chondrocytes on different PLLA films and tissue culture plates. Cell viability was estimated by the MTT assay and cell function were assessed by measuring sulfated glycosaminoglycan secreted by chondrocytes. These results implied that chitosan used to modify PLLA surface through entrapment and coupling could enhance the chondrocyte adhesion, proliferation and function.     

活动性类风湿关节炎患者sICAM-1、sVCAM-1的变化及意义

目的 :测定活动性类风湿关节炎 (RA)患者血清中sICAM 1、sVCAM 1水平 ,探讨sICAM 1、sVCAM 1与IL 1、TNF、IFN γ及病情的关系。方法 :用酶联免疫分析法 (ELISA)检测 30例活动性RA患者与 30例健康对照者sICAM 1、sVCAM 1、IL 1、TNF、IFN γ水平。结果 :RA患者血清sICAM 1、sVCAM 1、IL 1、TNF、IFN γ水平明显高于正常对照组 (P<0 0 0 1) ,sICAM 1与IL 1、IFN γ正相关 ,与RF亦呈正相关 ,sVCAM 1与IL 1、TNF、IFN γ正相关 ,与ESR、CRP、Stock指数正相关。结论 :RA患者血清sI CAM 1、sVCAM 1水平显著升高 ,sICAM 1、sVCAM 1可能参与RA发病过程 ,sICAM 1可作为判断病情严重性的指标 ,sVCAM 1可作为观察病情活动性的指标。     

反义CD40RNA对EB病毒转化的B细胞CD40分子表达和增殖能力的影响

目的 :探讨瞬时表达的反义CD4 0RNA ,对EB病毒转化的健康人B细胞膜表面CD4 0分子表达和增殖能力的影响。方法 :应用T A克隆技术和亚克隆技术 ,构建人反义CD4 0RNA的真核表达载体pcDNA3/CD4 0 ,并以其转染本室建立的EB病毒转化的健康人B细胞。应用流式细胞仪 (FACS) ,检测B细胞膜上CD4 0分子表达的变化。应用MTT比色法检测反义CD4 0RNA对B细胞增殖能力的影响。结果 :与转染空载体pcDNA3组相比 ,转染pcDNA3/CD4 0细胞上CD4 0分子的表达降低 (P<0 .0 1) ,其增殖能力明显降低 (P <0 .0 1)。结论 :反义CD4 0RNA技术 ,可作为有效的免疫调控手段。CD4 0基因本身在细胞的生长代谢中也起着重要作用     

饮酒对小鼠睾丸生精小管一氧化氮合酶、增殖细胞核抗原表达及细胞凋亡影响的研究

目的　探讨酒精对小鼠睾丸的组织结构、内皮型一氧化氮合酶 (eNOS)、增殖细胞核抗原 (PCNA)及细胞凋亡的影响。　方法　用 5 %、10 %及 15 % 3种不同浓度的酒精作用于 2 2d龄小鼠 ,取睾丸做石蜡切片、HE染色 ;用免疫组织化学方法检测睾丸eNOS、细胞增殖的变化 ;TUNEL法检测细胞凋亡的变化 ,并进行统计学分析。　结果　随着酒精浓度的增大 ,睾丸组织结构发生明显改变 ,生精小管的直径逐渐减小 ,eNOS阳性细胞面积密度逐渐增大 ,单位面积内PCNA阳性细胞和凋亡细胞数目增加 ,高浓度酒精组与其他组差异极显著 (P <0 0 1)。　结论　酒精可使生精小管的直径变小 ,eNOS及PCNA表达增强 ,凋亡细胞增加并随酒精浓度的增大而变化加重。这可能是过量饮酒导致生精细胞减少 ,生殖能力降低的重要因素。     

13C MRS of occipital and frontal lobes at 3 T using a volume coil for stochastic proton decoupling

Previously, we devised a novel strategy for in vivo ¹³C MRS using [2‐¹³C]glucose infusion and low‐power proton decoupling, and proposed that this strategy could be used to acquire ¹³C MR spectra from the frontal lobe of the human brain. Here, we demonstrate, for the first time, in vivo ¹³C MRS of human frontal lobe acquired at 3 T. Because the primary metabolites of [2‐¹³C]glucose can be decoupled using very‐low‐radiofrequency power, we used a volume coil for proton decoupling in this study. The homogeneous B₁ field of the volume coil was found to significantly enhance the decoupling efficiency of the stochastic decoupling sequence. Detailed specific absorption rates inside the human head were analyzed using the finite difference time domain method to ensure experimental safety. In vivo ¹³C spectra from the occipital and frontal lobes of the human brain were obtained. At a decoupling power of 30 W (time‐averaged power, 2.45 W), the spectra from the occipital lobe showed well‐resolved spectral resolution and excellent signal‐to‐noise ratio. Although frontal lobe ¹³C spectra were affected by local B₀ field inhomogeneity, we demonstrated that the spectral quality could be improved using post‐acquisition data processing. In particular, we showed that the frontal lobe glutamine C5 at 178.5 ppm and aspartate C4 at 178.3 ppm could be spectrally resolved with effective proton decoupling and B₀ field correction. Because of its large spatial coverage, volume coil decoupling provides the potential to acquire ¹³C MRS from more than one brain region simultaneously. Copyright © 2010 John Wiley & Sons, Ltd.     

糖皮质激素对大鼠骨折愈合方式的影响

目的:探讨糖皮质激素对大鼠骨干骨折愈合方式的影响。方法:取3月龄雌性SD大鼠60只分为实验组和对照组,实验组肌肉注射醋酸强的松5mg·kg-1.d-1,对照组注射等容积的生理盐水。3周后制成胫骨干骨折模型,骨折后不同阶段处死,分别进行组织学、骨密度、Western印迹检测骨痂中Ⅱ型胶原蛋白的表达以及生物力学测定。结果:肌肉注射醋酸强的松3周后骨密度检查证实模型制造成功。骨折后第3d2组均开始形成原始骨痂;第2周实验组软骨骨痂明显比对照组少,第4-6周实验组骨痂面积高于对照组,且软骨骨痂比例较高,骨密度减低。实验组中Ⅱ型胶原蛋白表达明显延迟。第6周生物力学测定对照组实际最大载荷为(69.77±8.46)N,较实验组(51.38±3.37)N增加35.8%。结论:大剂量糖皮质激素在大鼠骨折早期延缓软骨骨痂的产生,在骨折中后期使软骨性骨痂至骨性骨痂演变过程减缓。Ⅱ型胶原蛋白的表达延迟可能是其对骨折愈合产生不利影响的原因之一。     

血栓素合酶基因Pro1770Leu多态性与新疆维吾尔族心肌梗死的相关性研究

目的 探讨血栓素合酶基因CYP5A1 Pro1770Leu多态性与新疆维吾尔族心肌梗死的相关性.方法 采用聚合酶链反应-限制性片段长度多态性方法,对315例心肌梗死患者和218名健康受试者血栓素合酶基因第13外显子Pro1770Leu位点进行分析,同时进行血清血栓素B2(thromboxane B2,TXB2)水平测定.结果 血栓素合酶基因第13外显子Pro1770Leu在病例组和健康对照组中基因型频率分别为:CC型0.933和0.977,TC型0.067和0.023,病例组TC型高于对照组(P＜0.05),且T等位基因频率显著高于对照组(P＜0.05),血清TXB2水平病例组较对照组明显增高,差异具有统计学意义(P＜0.05);TC基因型携带者血清TXB2水平较CC基因型者增高,差异具有统计学意义(P＜0.05).结论 血栓素合酶基因第13外显子Pro1770Leu基因多态性和新疆维吾尔族心肌梗死的发生具有相关性,可能与基因变异导致的血清TXB2水平增高有关.     

猪、小牛与人颈椎的生物力学比较

目的 比较猪、小牛与人颈椎功能节段的生物力学,确定猪与小牛颈椎是否适合在脊柱体外研究中替代人的脊柱标本。方法取12具1岁龄,60~80 kg猪龄颈椎（颈0-胸1）,12具1周龄,40~50 kg小牛的颈椎（颈0-胸1）。12具标本分成两组,一组6具被分成C2-C3,C4-C5,C6-C7;另一组被分成C3-C4,C5-C6。每个功能节段（C2-C3,C3-C4,C4-C5,C5-C6,C6-C7）分别测试。连续测试前屈后伸、旋转、侧弯上的活动范围和中性区,并同已发表的人体颈椎活动度进行比较。结果中性区：在旋转和前屈后伸方向上,小牛和人颈椎的中性区比较相近,但远大于猪颈椎的中性区;在左右侧弯方向上,猪C2-C3为人的中性区69.7％,猪C6-C7约为人的中性区60.4％,余节段均相差较大;小牛颈椎与人颈椎在C2-C3上十分相近,余节段也相差较大。活动范围：在前屈后伸和左右侧屈上,猪与人颈椎的活动十分相近,均远小于小牛颈椎的活动度,约为其的50％;在旋转方向上,猪C2-C3约为人的69％,余节段均小于人颈椎;小牛颈椎远大于人颈椎,最相近的为C4-C5上,相差3.5°。结论猪的C2-C3,C6-C7的生物力学可以替代人颈椎进行各种方向生物力学实验;小牛颈椎的活动度普遍大于人,小牛C2-C3,C3-C4的生物力学同人比较相似。     

颈胸段脊柱骨折的临床特点及后路手术疗效探讨

目的探讨颈胸段脊柱脊髓损伤的临床特点及后路椎板减压、植骨、椎弓根螺钉内固定术的治疗作用。方法 8例颈胸段脊柱损伤患者,损伤部位为第6颈椎至第1胸椎,损伤类型为椎体爆裂性骨折2例,椎体压缩性骨折5例,压缩性骨折伴脱位1例。分析上述患者的临床表现,并分别经后路颈胸段椎板减压椎弓根或侧块螺钉内固定术。结果所有患者随访6~20个月,植骨均在3~4个月完全融合,所有患者术后脊髓神经功能均有不同程度症状改善,伴有交感神经节刺激症状者有所缓解。结论颈胸段后路椎板开窗减压植骨融合内固定术对颈胸段脊柱脊髓损伤具有较好的疗效。后路椎弓根螺钉及侧块螺钉固定系统有助于植骨节段融合、重建和稳定颈胸段脊柱。