辐射诱导的适应性效应及其分子机制

辐射适应性效应是一种生物防御机制,是指低剂量辐射可以增强细胞对随后高剂量照射的抵抗能力,从而降低高辐射引起的各种损伤.目前为止,RAR的分子机制还不清楚,研究主要涉及DNA损伤修复、细胞周期调控、细胞对抗氧化应激系统以及应激反应蛋白,参与细胞信号传递的分子主要包括蛋白激酶C、有丝分裂原激活蛋白激酶、p53蛋白、共济失调性毛细血管扩张突变基因及DNA依赖性蛋白激酶.     

组蛋白去乙酰酶阻滞剂的放射增敏作用

放射治疗是肿瘤的重要治疗手段之一,辐射可以导致细胞DNA双链断裂。细胞主要通过同源重组修复和非同源末端连接修复方式修复DNA双链断裂。随着对双链DNA损伤修复机制认识的深化,组蛋白去乙酰酶（HDAC）阻滞剂成为提高放射敏感性的一种新策略。HDAC可分为4类。HDAC阻滞剂可非特异性地或特异性地阻滞这4类HDAC,使组蛋白乙酰化水平提高,染色体解螺旋,核小体结构改变。一方面使DNA更易受到辐射的影响;另一方面通过降低E2F1转录因子活性抑制损伤修复蛋白Ku80、Rad51等的表达,使其不能募集DNA损伤修复蛋白,且不能形成相应的蛋白复合物,使同源重组修复和非同源末端连接修复作用延缓,在伴有或不伴有肿瘤细胞凋亡增加的情况下,提高放射敏感性。现已有一些临床试验在进行中,并取得了初步的结果。     

角质细胞生长因子及其辐射防护作用

角质细胞生长因子(KGF)是具有肝素结合特性的成纤维细胞生长因子(FGF)家族中的一员,又称为FGF-7。尽管KGF来源于不同的组织,KGF仅特异性地作用于上皮细胞。KGF可提高辐射后小鼠肠干细胞的存活率,并对辐射引起气道上皮细胞的通透性升高具有拮抗作用。KGF可以加速辐射诱导的DNA损伤的修复,并对维持细胞骨架蛋白F-肌纤蛋白的稳定和保护细胞间连接具有重要作用,其信号转导是通过蛋白激酶C(PKC)途径完成的。因此,不少作者认为,KGF很有希望成为临床上用于胸部、腹部肿瘤放化疗防护的细胞因子。     

Ku蛋白在肿瘤发生中的作用及其靶向抑制策略

Ku蛋白参与辐射诱导的DNA损伤修复,严重影响着肿瘤细胞的辐射敏感性。细胞内Ku蛋白异常表达与肿瘤发生和发展存在密切关系。目前,研究者试图抑制Ku蛋白表达来增强肿瘤细胞的辐射敏感性,为进一步靶向治疗奠定基础。     

低剂量辐射刺激作用的实验研究

本文报告低剂量,低LET辐射对小鼠免疫功能、染色体畸变和DNA损伤修复影响的实验资料。低剂量单次x线或持续γ线全身照射后,出现辐射刺激效应,表现为(1)增强免疫功能,包括抗体形成反应增强、自介素2产生增多、NK活性增高、胸膜细胞增殖加快和ConA诱导的大分子合成激活,(2)诱导细胞遗传学适应性反应,即低剂量辐射预先作用使相继较大剂量所致染色体损伤减轻； (3)促进DNA修复,包括非程序DNA合成增强和DNA聚合酶活性增高。对辐射刺激效应的发生机理和意义进行了讨论。     

鼻咽癌细胞辐射抗拒的比较蛋白质组学分析

目的 通过分离并鉴定具有不同辐射抗拒的人鼻咽癌细胞株CNE-2R与CNE-2的差异表达蛋白,探讨与鼻咽癌细胞辐射抗拒相关的分子机制.方法 分别提取鼻咽癌辐射抗拒细胞株CNE-2R及其亲本细胞株CNE-2的总蛋白,采用双向凝胶电泳分离,经软件分析识别差异表达蛋白点,应用基质辅助激光解析电离飞行时间串联质谱技术(MALDI-TOF-MS)鉴定差异蛋白质.结果 两种不同辐射敏感性的鼻咽癌细胞株CNE-2R和CNE-2中,共筛选出差异表达明显的蛋白质点有32个,其中11个蛋白质被鉴定成功,在CNE-2R中上调的蛋白有3个,下调的蛋白有8个.结论 不同辐射敏感性的鼻咽癌细胞的差异表达蛋白,主要涉及调节凋亡、DNA损伤与修复、细胞周期调控、RNA转录、细胞信号转导、细胞骨架组成及辐射应激反应等多个方面.     

抗辐射球菌辐射抗性机制的研究

抗辐射球菌是一种对电离辐射和其他DNA损伤因子有极强抵抗能力的细菌。对它的研究主要集中在揭示其对DNA损伤的抗性机制和如何利用它清除辐射废料。现有研究认为,该菌的抗性机制主要缘于三个方面:(1)DNA损伤的高效修复;(2)特殊的生存方式;(3)对氧自由基的有效清除。     

抗辐射球菌辐射抗性机制的研究

抗辐射球菌是一种对电离辐射和其他DNA损伤因子有极强抵抗能力的细菌。对它的研究主要集中在揭示其对DNA损伤的抗性机制和如何利用它清除辐射废料。现有研究认为，该菌的抗性机制主要缘于三个方面：(1)DNA损伤的高效修复；(2)特殊的生存方式；(3)对氧自由基的有效清除。     

低剂量辐射兴奋效应的研究及临床应用

电离辐射广泛存在于人们的生活环境中,低剂量辐射可诱发机体产生适应性反应,其机制包括DNA损伤修复、促进T细胞内信息传递、保护性蛋白的产生、反应性氧类的作用,还能增强免疫力、抑制肿瘤的生长和转移及对化疗不良反应产生影响,具有肿瘤治疗的潜在临床意义。     

低剂量辐射诱导适应性反应的分子机制研究现状

低剂量辐射(low dose radiation，LDR)可以增强细胞对随后进行的攻击性剂量(challenge dose)照射的抵抗能力，从而降低攻击性照射引起的染色体畸变和DNA损伤。人们把LDR的这种效应称之为“低剂量辐射诱导的适应性反应”。低剂量辐射诱导适应性反应的分子机制主要涉及细胞信号转导、ROS(活性氧物质)的作用和DNA修复兴奋效应等方面。     

Knee injury and Osteoarthritis Outcome Score (KOOS) - validation of a Swedish version

The Knee injury and Osteoarthritis Outcome Score (KOOS) is a self-administered instrument measuring outcome after knee injury at impairment, disability, and handicap level in five subscales. Reliability, validity, and responsiveness of a Swedish version was assessed in 142 patients who underwent arthroscopy because of injury to the menisci, anterior cruciate ligament, or cartilage of the knee. The clinimetric properties were found to be good and comparable to the American version of the KOOS. Comparison to the Short Form-36 and the Lysholm knee scoring scale revealed expected correlations and construct validity. Item by item, symptoms and functional limitations were compared between diagnostic groups. High responsiveness was found three months after arthroscopic partial meniscectomy for all subscales but Activities of Daily Living.     

Endovascular management of carotid-cavernous fistulas

Objective To investigate endovascular treatment of traumatic direct carotid-cavernous fistulas （CCF） and their complications such as pseudoaneurysms. Methods： Over a five-year period, 22 patients with traumatic direct CCFs were treated endovascularly in our institution. Thirteen patients were treated once with the result of CCF occluded, 8 twice and 1 three times. Treatment modalities included balloon occlusion of the CCF, sacrifice of the ipsilateral internal carotid artery with detachable balloon, coll embolization of the cavernous sinus and secondary pseudoaneurysms, and covered-stem management of the pseudoaneurysms. Results All the direct CCFs were successfully managed endovascularly. Four patients developed a pseudoaneurysm after the occlusion of the CCF with an incidence of pseudoaneurysm formation of 18.2% （4/22）. A total number of 8 patients experienced permanent occlusion of the ICA with a rate of ICA occlusion reaching 36.4% （8/22）. Followed up through telephone consultation from 6 months to 5 years, all did well with no recurrence of CCF symptoms and signs. Conclusion Traumatic direct CCFs can be successfully managed with endovascular means. The pseudoaneurysms secondary to the occlusion of the CCFs can be occluded with stent-assisted coiling and implantation of covered stents.     

The acutely limping child

Acute limping may be the result of multiple pathologies in children. The differential diagnosis varies based on the age of the child. Irrespective of age, the initial imaging work-up includes AP and frog leg radiographs of the pelvis and ultrasound; MRI may sometimes be helpful. In children less than 3 years, infections and trauma are most frequent. MRI is the imaging modality of choice when osteomyelitis is clinically suspected. Between the ages of 3 and 10 years, transient synovitis of the hip and Legg-Calvé-Perthes disease are main considerations but infection, inflammation and focal bony lesions are also considered. In children over 10 years, slipped capital femoral epiphysis also is considered.     

Do Balance Board Training Programs Reduce the Risk of Ankle Sprains in Athletes?

Introduction Ankle sprains are the most common musculo-skeletal injury that occurs in athletes,particularly in sports that require jumping and landing on one foot such as soccer,and basketball(1-4).These injuries often result in significant time loss from participation,long-term disability,and have a major impact on health care costs and resources(5-8).     

High Intensity Interval Training:New Insights

KEY POINTS ·High-intensity interval training(HIT)is characterized by repeated sessions of relatively brief，intermittent exercise.often performed with an“a11 out”effort or at an intensity close to that which elicits peak oxygen uptake(i.e.，≥90%of VO2 peak).     

人体中的镭-226、镭-228、钋-210、铅-210

本文报道了广东阳江高本底地区6名、对照地区8名人尸体的骨²²⁶Ra、²²⁶Ra的浓度以及部分居民内脏器官中。²¹⁰Po、²¹⁰Pb的浓度。结果轰明阳江高本底地区和对照地区居民骨镭-226、镭-228的浓度分别为29.9pCi/kg, 26.9pCi/kgl 8.7pCi/kg, 8.2pCi/kg.由此估算出阳江高本底地区屠民骨中²²⁶Ra、²²⁸Ra的负薄璧及对骨衬、骨髓所产生的剂量当量分别为对照地区民民的3.4倍, 3.3倍。两地区居民内脏器官中^{210Po、210Pb的测定分析铡数较少但仍看出, 高本底地区均明显高于对照地区.}