生物可吸收依维莫司洗脱冠状动脉支架系统2年随访及多种成像法结果

<正> 生物可吸收支架较金属药物洗脱支架(DES)有可能减少晚期支架内血栓(ST)的发生,因不存在外源性的金属材料和血液相接触,所以不必顾虑血管内皮化延迟或不完全。此外,永久置入的金属支架会影响外科血运重建,堵塞边支血管,妨碍血管的扩张性重塑和血管舒缩反应,还将影响非介人性检查如冠脉多层CT和MRI的成像。作为金属DES     

嗅鞘细胞移植对脊髓损伤区RhoA表达的影响

目的:轴突生长抑制分子须与其共同复合受体结合后才能激活下游抑制信号RhoA,从而导致细胞骨架塌陷,抑制神经再生。基础及临床研究均证实嗅鞘细胞能够促进脊髓功能的恢复,观察嗅鞘细胞移植前后脊髓损伤区RhoA的动态变化,探讨嗅鞘细胞移植治疗脊髓损伤的可能机制。方法:实验于2005-09/2006-05在西安交大医学院环境与基因重点实验室完成。①实验动物:成年SD大鼠40只,随机数字表法分为正常组、模型组、嗅鞘细胞组、DF12对照组,10只/组。另取30只健康成年雄性SD大鼠作为嗅鞘细胞的来源。实验过程中对动物的处置符合动物伦理学标准。②实验方法:大鼠麻醉后处死,迅速取出头部两侧嗅球,除去软膜,剪取嗅球外面的嗅神经层和小球层,剪碎后离心,胰蛋白酶消化获取嗅鞘细胞悬液。除正常组外,其余各组均建立全横切脊髓损伤模型。嗅鞘细胞组将原代培养12 d的嗅鞘细胞悬液调整为1×10~(11)L~(-1),在距损伤缘上下各1 mm处分4点应用微量注射器注射,深度1.0 mm,每处各注射1μL。DF12对照组同法每点注射等量DF12培养液,模型组、正常组不进行任何处理。③实验评估:各组分别于移植后1,2,4,6,8周采用免疫组化和Western blot免疫印迹技术动态检测脊髓损伤区RhoA表达的变化。同时在移植后8周行嗜银染色检测组织形态学变化。结果:①RhoA表达的变化:正常组RhoA表达的吸光度值明显低于其余3组(P<0.05)。嗅鞘细胞组于移植后1,2,4,6,8周脊髓损伤区RhoA的表达均明显低于模型组和DF12对照组(P<0.01),而模型组和DF12对照组差异无显著性意义(P> 0.01)。②组织形态学变化:嗅鞘细胞移植8周后除正常组外,其余各组均可见明显的神经纤维再生,但模型组与DF12对照组大部分纤维排列紊乱,再生纤维方向性较差;嗅鞘细胞组可见明显的新生轴突,且神经纤维跨越损伤部位修复脊髓损伤,无论在数量还是质量上均优于模型组及DF12对照组。结论:嗅鞘细胞移植可能通过降低脊髓损伤区RhoA蛋白的表达,从而促进损伤脊髓的修复。     

嗅鞘细胞移植对脊髓损伤大鼠诱发电位的影响

目的:观察嗅鞘细胞移植对脊髓损伤大鼠感觉及运动诱发电位的影响,尝试用嗅鞘细胞移植修复脊髓损伤后受损的传导通路。方法:实验于2004-09/2006-07在西安交通大学口腔医学实验中心完成。①选取成年健康SD大鼠40只,取16只大鼠用于嗅鞘细胞的培养与纯化,剩余24只随机数字表法分为4组:假手术组、模型对照组、嗅鞘细胞移植组、DF12培养液组,6只/组。②模型对照组、嗅鞘细胞移植组、DF12培养液组采用脊髓横切法制作脊髓损伤模型,以T10为中心的后正中切口入路,切除T10全椎板及T9,T11的部分椎板,显露脊髓,以特制探针横预置3-0丝线于待损伤脊髓腹侧硬膜外,以剃须刀片于预置线头侧0.5mm(T10水平)将脊髓横断。假手术组仅切开T10全椎板及T9,T11的部分椎板,对脊髓未作横断处理。③造模后,嗅鞘细胞移植组以距脊髓断端1mm的平面与正中线交点为进针点,每一进针点按1.75mm,1.25mm,1.00mm,0.50mm4个不同深度分别注射嗅鞘细胞培养液0.5μL,注射速度0.1μL/min,每注射位点留针5min。DF12培养液组同法注射0.5μL无血清的D/F12培养液。假手术组、模型对照组未作处理。④术后8周,各组大鼠麻醉后使用DantecKeypoint型四导诱发电位肌电图仪测定感觉及运动诱发电位的潜伏期及波幅变化。结果:24只大鼠全部进入结果分析。①嗅鞘细胞移植术后大体观察:术后6周,嗅鞘细胞移植组双后肢拖步爬行、双侧膝踝关节处溃疡和压疮等失神经支配征象逐渐好转,股四头肌肌力明显恢复,拖步爬行现象改善;而模型对照组、DF12培养液组大鼠失神经支配征象无改善,假手术组未见异常。②术后8周感觉诱发电位检测结果:模型对照组、DF12培养液组均未引出感觉诱发电位波形。与假手术组比较,嗅鞘细胞移植组感觉诱发电位潜伏期明显延长[(2.640±0.294),(14.575±2.117)ms,P<0.01],波幅显著降低[(3.797±0.140),(0.403±0.078)μV,P<0.01]。③模型对照组、DF12培养液组均未引出运动诱发电位波形。与假手术组比较,嗅鞘细胞移植组运动诱发电位潜伏期明显延长[(5.825±0.350),(10.750±1.184)ms,P<0.01],波幅显著降低[(5.200±0.432),(0.10±0.001)μV,P<0.01]。结论:嗅鞘细胞移植治疗可以调节损伤脊髓的内在微环境,加强体感诱发电位和运动诱发电位的恢复表达,改善神经功能。     

Two‐drug vs. three‐drug combinations for HIV‐1: Do we have enough data to make the switch?

Three‐drug combination antiretroviral therapy (ART) became available in 1996, dramatically improving the prognosis of people living with HIV. The clinical benefits of ART are due to the sustained viral load suppression and CD4 T cell gains. Major drawbacks of the first ART regimens were adverse events, and high pill burden, which led to the reduction of drug adherence resulting in frequent treatment discontinuations and the development of drug resistance. Due to increased viral potency of new antiretroviral drugs consideration of a two‐drug combination therapy repositioning occurred in an effort to reduce adverse events, drug‐drug interactions and cost, while maintaining a sustained antiviral effect. Various combinations of two‐drug regimens have been studied, and non‐inferiority compared to a three‐drug regimen has been shown only for some of them. In addition, a two‐drug combination regimen may not be suitable for every patient, especially those who are pregnant, those with tuberculosis or coexisting HBV infection. Furthermore no information has been generated concerning the secondary transmission of HIV from patients who have undetectable plasma viral load on two‐drug regimens. Additional studies of two‐drug combinations are also necessary to evaluate the debated existence of low viral replication in tissues and on immune activation. While there is no urgent need to routinely switch patients to two‐drug combination therapy, due to the availability of drug combinations without significant toxicities, dual regimens represent a suitable option that deserve long‐term evaluation before being introduced to clinical practice.     

Clinical review: Exogenous surfactant therapy for acute lung injury/acute respiratory distress syndrome - where do we go from here?

Acute lung injury and acute respiratory distress syndrome (ARDS) are characterised by severe hypoxemic respiratory failure and poor lung compliance. Despite advances in clinical management, morbidity and mortality remains high. Supportive measures including protective lung ventilation confer a survival advantage in patients with ARDS, but management is otherwise limited by the lack of effective pharmacological therapies. Surfactant dysfunction with quantitative and qualitative abnormalities of both phospholipids and proteins are characteristic of patients with ARDS. Exogenous surfactant replacement in animal models of ARDS and neonatal respiratory distress syndrome shows consistent improvements in gas exchange and survival. However, whilst some adult studies have shown improved oxygenation, no survival benefit has been demonstrated to date. This lack of clinical efficacy may be related to disease heterogeneity (where treatment responders may be obscured by nonresponders), limited understanding of surfactant biology in patients or an absence of therapeutic effect in this population. Crucially, the mechanism of lung injury in neonates is different from that in ARDS: surfactant inhibition by plasma constituents is a typical feature of ARDS, whereas the primary pathology in neonates is the deficiency of surfactant material due to reduced synthesis. Absence of phenotypic characterisation of patients, the lack of an ideal natural surfactant material with adequate surfactant proteins, coupled with uncertainty about optimal timing, dosing and delivery method are some of the limitations of published surfactant replacement clinical trials. Recent advances in stable isotope labelling of surfactant phospholipids coupled with analytical methods using electrospray ionisation mass spectrometry enable highly specific molecular assessment of phospholipid subclasses and synthetic rates that can be utilised for phenotypic characterisation and individualisation of exogenous surfactant replacement therapy. Exploring the clinical benefit of such an approach should be a priority for future ARDS research.     

Experimental transmission and pathogenesis of immunodeficiency syndrome in cats

We describe the identification, experimental transmission, and pathogenesis of a naturally occurring powerfully immunosuppressive isolate of feline leukemia virus (designated here as FeLV-FAIDS) which induces fatal acquired immunodeficiency syndrome (AIDS) in 100% (25 of 25) of persistently viremic experimentally infected specific pathogen- free (SPF) cats after predictable survival periods ranging from less than 3 months (acute immunodeficiency syndrome) to greater than one year (chronic immunodeficiency syndrome), depending on the age of the cat at time of virus exposure. The pathogenesis of FeLV-FAIDS-induced feline immunodeficiency disease is characterized by: a prodromal period of largely asymptomatic viremia; progressive weight loss, lymphoid hyperplasia associated with viral replication in lymphoid follicles, lymphoid depletion associated with extinction of viral replication in lymphoid follicles, intractable diarrhea associated with necrosis of intestinal crypt epithelium, lymphopenia, suppressed lymphocyte blastogenesis, impaired cutaneous allograft rejection, hypogammaglobulinemia, and opportunistic infections such as bacterial respiratory disease and necrotizing stomatitis. The clinical onset of immunodeficiency syndrome correlates with the replication of a specific FeLV-FAIDS viral variant, detected principally as unintegrated viral DNA, in bone marrow, lymphoid tissues, and intestine. Two of seven cats with chronic immunodeficiency disease that survived greater than 1 year after inoculation developed lymphoma affecting the marrow, intestine, spleen, and mesenteric nodes. Experimentally induced feline immunodeficiency syndrome, therefore, is a rapid and consistent in vivo model for prospective studies of the viral genetic determinants, pathogenesis, prevention, and therapy of retrovirus-induced immunodeficiency disease.