黄芪总黄酮对犬模拟肺癌术中放疗抗辐射损伤作用的…

电离辐射作用机体后可产生自由基，作者以模拟肺癌术中放疗的动物为实验对象，研究了黄芪总黄酮（ＴＦＡ）可清除自由基功效从而了解其抗辐射损伤作用。结果表明ＴＦＡ可有效的防止术中放疗所致的组织细胞损伤，使照射后组织的ＭＤＡ含量下降，ＳＯＤ活性受到保护，减轻肺组织充血、实交，胸膜粘连和食道粘膜糜烂等反应，并证明肺癌术中放疗可因电离辐射而产生自由基损伤。这种损伤不仅发生在胸腔内直接受照射的组织，在其他远隔部位     

60Coγ射线照射后伤口组织生长因子基因表达的变化及苯妥因钠的作用

目的研究全身γ射线照射后伤口组织生长因子基因表达的变化及苯妥因钠的作用。方法采用置入聚乙烯醇海绵的大鼠背部切口伤模型,用原位杂交技术和计算机图像分析技术测定伤口组织中血小板源性生长因子Ｂ（ＰＤＧＦＢ）和转化生长因子β１（ＴＧＦβ１）ｍＲＮＡ表达的平均吸光度。结果６Ｇｙ全身照射后伤口组织中ＰＤＧＦＢ和ＴＧＦβ１ｍＲＮＡ阳性表达平均吸光度明显下降;苯妥因钠对单纯创伤和全身照射合并创伤的伤口组织中ＰＤＧＦＢ和ＴＧＦβ１ｍＲＮＡ表达的平均吸光度有明显的提高。结论这说明伤口组织中生长因子基因表达的降低是全身照射后创伤愈合延迟的分子机制之一;苯妥因钠上调伤口组织中生长因子基因表达而有利于创伤愈合。     

^60Coγ射线照射后伤口组织生长因子基因表达的变？…

目的 研究全身γ射线照射后伤口组织生长因子基因表达的变化及苯妥因钠的作用。方法采用置入聚乙烯醇海绵的大鼠背部切口伤模型，用原位杂交技术和计算机图像分析技术测定伤口组织中血小板源性生长因子－Ｂ（ＰＤＧＦ－Ｂ）和转化生长因子－β１（ＴＧＦ－β１）ｍＲＮＡ表达的平均吸光度。结果 ６Ｇｙ全身照射后伤口组织中ＰＤＧＦ－Ｂ和ＴＧＦ－β１ｍＲＮＡ阳性表达平均吸光度明显下降     

大鼠肺吞噬细胞释放自由基在放射性肺炎发展中的作用

６０Ｃｏγ射线（２０Ｇｙ）照射大鼠胸部，以支气管－肺泡冲洗液细胞（ＢＡＬＦＣ）的化学发光作为吞噬细胞释放自由基的指标，用肺组织羟脯氨酸含量评价肺纤维细胞增殖程度，观察照后０．５，１和２个月时肺吞噬细胞释放自由基的变化及其与肺组织纤维细胞增殖性病变的可能关联。结果表明：随照后时间延长，ＢＡＬＦＣ数增加；ＢＡＬＦＣ化学发光的本底值降低，激活值增高；肺组织湿重增加，羟脯氨酸含量增高。这些损伤性变化在补硒后表现出明显的减轻或恢复性转变。进一步分析表明：照后ＢＡＬＦＣ在肺内聚集及其释放自由基的增高与肺纤维细胞增殖有一定的关联，提示肺内吞噬细胞释放的自由基可能是放射性肺炎病变发生发展的一个重要因素。     

电离辐射所致自由基对机体的损伤与自由基清除剂的研究

众所周知 ,随着核技术在工农业 ,医学生命科学等方面应用的迅速发展 ,人们与放射线接触的机会日益增多 ,遭受辐射损伤的可能性随之增加。在有氧条件下 ,大剂量照射 ,除电离辐射的直接作用 (电离激发 ,化学键断裂 )外 ,由于机体内存在 70 %的水 ,电离辐射因水辐解产生的大量自由基(间接作用 ) ,可造成生物大分子和生物膜的损伤 ,细胞功能丧失 ,细胞周期紊乱和遗传的变异。为了拮抗电离辐射的这种有害作用 ,筛选出在防止辐射损伤中具有抗氧化和拮抗自由基作用的清除剂引起了放射性工作者的极大关注。1971年ＡｒｅｎａＶ首次提出电离辐射产生Ｏ…     

一氧化氮损伤内皮细胞的机制研究

体外培养人脐静脉内皮细胞（ＨＵＶＥＣ），主要研究：①内毒素损伤内皮细胞过程中一氧化氮（ＮＯ）的作用；②不同浓度ＮＯ供体ＳＩＮ－１对内皮细胞的作用以及ＳＯＤ、ＣＡＴ对内皮细胞的保护作用。结果提示：ＮＯ在内毒素损伤内皮细胞过程中发挥重要作用；高浓度ＳＩＮ－１可严重损伤内皮细胞；ＳＯＤ、ＣＡＴ对内皮细胞的不同保护作用说明ＯＮＯＯ＾－的产生可能是ＮＯ损伤内皮细胞的重要机制。     

重组人铜锌超氧化物歧化酶对电离辐射损伤小鼠免疫细胞的影响(论著)

目的：探讨电离辐射对免疫细胞的影响及重组人铜锌超氧化物歧化酶（ｒｈＣｕＺｎＳＯＤ）的抗辐射作用。方法：观察６０Ｃｏγ射线５～７Ｇｙ照射前后不同时段给予ｒｈＣｕＺｎＳＯＤ对小鼠免疫细胞的影响。结果：电离辐射对小鼠免疫细胞有明显的损伤作用。与照射对照组比较，ｒｈＣｕＺｎＳＯＤ可减轻电离辐射对小鼠免疫细胞的影响，其作用包括增强脾Ｔ淋巴细胞对刀豆蛋白Ａ诱导的增殖反应，提高脾自然杀伤细胞的活性，升高全脾淋巴细胞及外周血白细胞和淋巴细胞的数量。辐射前后给药组的效果优于辐射前或辐射后给药组。结论：ｒｈＣｕＺｎＳＯＤ对防止免疫细胞的辐射损伤有一定作用。     

吞噬细胞释放的氧自由基和肿瘤坏死因子增加α粒子致细胞转化频率的研究

阐明慢性炎症时吞噬细胞释出的某些内源性因子在辐射致癌中的作用。方法以Ｃ３Ｈ１０Ｔ１／２和原代ＳＨＥ为靶细胞，用２３８Ｐｕ为体外α照射源，用转化灶形成法观察ＰＭＡ及其刺激人外周血产生的过量自由基、调理酵母多糖刺激Ｕ－９３７细胞释放的ＴＮＦ－α等炎性因子对α粒子照射细胞转化频率（ＴＦ）的增加效应。结果ＰＭＡ和它刺激的人血使０．５Ｇｙα粒子照射的Ｃ３Ｈ１０Ｔ１／２细胞的ＴＦ分别增高２．１和２．８倍。Ｕ－９３７释放的ＴＮＦ－α炎症因子ＴＦ增高１２倍；用抗ＴＮＦ－α抗体中和后，证明Ｕ－９３７上清中仍有其他促癌因子存在。０．５Ｇｙα粒子照射的ＳＨＥ细胞在体外长期传代生长对ｈｒＴＮＦ－α具有依赖性，由此得到的４０代的细胞具有致瘤性。结论慢性炎症条件下，中性粒细胞和巨噬细胞释出的过量自由基和ＴＮＦ－α等因子在低剂量辐射致癌中起重要作用。     

光动力疗法与热损伤对正常大鼠胃损伤的研究

为了初步探讨ＰＤＴ与热损伤对正常胃损伤作用机制的差异，本实验以血卟啉衍生物及氩离子泵染料激光器为光敏剂及光源，观察了大鼠胃壁在单纯氩离子激光照射和ＰＤＴ时，照射部位的温度及组织学在照射后７２小时和二周的改变。结果：氩离子激光照射组和ＰＤＴ组胃壁温度均高于对照组（Ｐ＜０．０１），但ＰＤＴ组温度均低于３７℃。氩离子激光照射后的胃壁组织在７２小时各层组织均明显出血，炎细胞浸润，组织凝固坏死。电镜下见胶原纤维肿胀，排列紊乱，甚至溶解吸收。二周后损伤部位以纤维瘢痕组织修复。ＰＤＴ组在７２小时胃壁组织也有充血和炎细胞浸润，但仅有轻度组织坏死，损伤深度未超过粘膜下层。电镜下见胶原纤维结构基本正常。二周后损伤部位以组织再生修复，未留瘢痕。结论：ＰＤＴ与氩离子激光组织损伤及修复方式不同，ＰＤＴ不损伤胃粘膜下胶原纤维。     

大鼠脊髓组织CNTFRα mRNA的表达及其坐骨神经损伤后表达的变化

目的：通过对大鼠脊髓组织中睫状神经营养因子受体α（ＣＮＴＦＲα）的分布与细胞定位及其在坐骨神经损伤后表达变化的研究，来探讨ＣＮＴＦ在脊髓组织中的可能作用。方法：利用原位杂交和点杂交的方法，对ＣＮＴＦＲα在大鼠脊髓组织中的分布与坐骨神经损伤后的表达变化进行研究。结果：ＣＮＴＦＲαｍＲＮＡ几乎存在于所有脊髓神经元与胶质细胞中；坐骨神经损伤后１ｄ表达增加，以后降到较低水平，到１４ｄ再次升高，但第２峰较第１峰为低。结论：ＣＮＴＦＲαｍＲＮＡ在大鼠脊髓组织中的广泛分布，表明ＣＮＴＦ对脊髓组织各类神经元与胶质细胞均有神经营养作用。坐骨神经损伤后１ｄ，ＣＮＴＦＲαｍＲＮＡ表达的增加，可能与损伤应激相关；１４ｄ的再次升高是否由于再生过程中，雪旺细胞大量增殖，ＣＮＴＦ大量表达所诱导，还有待进一步的研究；ＣＮＴＦＲα表达的改变，可能是损伤神经元在损伤与再生修复过程中，神经元本身代谢适应性改变的一部分     

Calcium antagonists protect mice against lethal doses of ionizing radiation.

Currently available radioprotectors are poorly tolerated in man and the general use of aminothiol radioprotectors is compromised by their side-effects. In a search for less toxic radioprotective agents, diltiazem, a calcium antagonist with a benzothiazepine structure, was found to protect mice against a lethal (LD100) gamma radiation dose allowing survival of up to 93%. Dihydropyridine calcium antagonists such as nifedipine, nimodipine, isradipine and nitrendipine also provided radioprotection. Calcium antagonists might attenuate radiation-induced injury by inhibiting cellular calcium overload, subsequent to cell membrane damage caused by radiation-generated free radicals. In view of their good tolerance, calcium antagonists may be applied safely in situations of radiation exposure, including radiotherapy and internal radionuclide contamination. These calcium antagonists may also be viewed in other contexts where free radicals are implicated in pathological processes.     

The application of thin layer activation for on-line erosion monitoring.

The washout of volcanic ash into the feedwater of a hydroelectric power station resulted in enhanced erosion of generator components. The damage prompted two novel applications of the thin layer activation (TLA) technique. TLA was used to select more resistant materials, and also as the basis of an automated, on-line alarm system to warn station operators on the likelihood of further damage. The latter application demonstrated that plant protection against irregular events is practical using TLA.     

Biochemical mechanisms for oxygen free radical formation during exercise

The biochemical mechanisms behind skeletal muscle soreness and damage with muscular overuse have remained unclear. Recently, however, a growing amount of evidence indicates that free radicals play an important role as mediators of skeletal muscle damage and inflammation. During exercise, two of the potentially harmful free radical generating sources are semiquinone in the mitochondria and xanthine oxidase in the capillary endothelial cells. During high intensity exercise the flow of oxygen through the skeletal muscle cells is greatly increased at the same time as the rate of ATP utilisation exceeds the rate of ATP generation. The metabolic stress in the cells causes several biochemical changes to occur, resulting in a markedly enhanced rate of production of oxygen free radicals from semiquinone and xanthine oxidase. During normal conditions free radicals are generated at a low rate and subsequently taken care of by the well developed scavenger and antioxidant systems. However, a greatly increased rate of free radical production may exceed the capacity of the cellular defence system. Consequently, a substantial attack of free radicals on the cell membranes may lead to a loss of cell viability and to cell necrosis and could initiate the skeletal muscle damage and inflammation caused by exhaustive exercise.     

Sensitivity of Artemia Eggs to γ-irradiation

Summary

The present experiments pertain to the relationship between radical amount measured by E.S.R. and biological damage of dried Artemia eggs irradiated with γ-rays.

(1) The amount of free radicals increased with the increase of the dose of irradiation; however, the relation was not linear. At the same time, the hatchability rate of the eggs decreased with the exposure dose, producing a sigmoid curve.

(2) The amount of free radicals produced by irradiation in the intact eggs was similar to that in the denuded eggs.

(3) The radical decay was very rapid, immediately after irradiation, then retarded. However, hatchability decreased continuously with time after irradiation.

(4) The hatchability and radical-decay rate of the irradiated eggs stored at 25°c decreased much more rapidly than those at dry-ice temperature.

From these results, it is concluded that decay of free radicals does not imply recover from radiation damage but continues to the point of fixation of the damage.     

Current state and possibilities of radiotherapy in the inter- disciplinary treatment of malignancies of the stomach, pancreas and biliary tract. II. Pancreatic cancer

The extremely unfavorable prognosis of the carcinoma of the pancreas is due to the fact that a curative operation - even by ultraradical surgery - is already impossible in 75 to 90% of patients at the moment of diagnosis. Contrary to expectation this situation has not been essentially improved by the introduction of modern, non-invasive examination methods such as ultrasound and computed tomography. Thus medical science is confronted again with the task of searching for operation modalities, especially for patients whose tumors are curatively inoperable but still restricted to the pancreatic region. Today the efficacy of radiotherapy can be considered to be proved also with respect to the carcinoma of the pancreas. The available results seem to indicate that the effect of radiotherapy depends on the dose and that the combination of radiotherapy and chemotherapy is more efficient than radiotherapy alone. It is not known yet if the effect of additional chemotherapy is only of a locally adjuvant or also of a systemic nature. Similarly to the carcinoma of the stomach, direct intraoperative irradiation - alone or combined to percutaneous irradiation - brings about the greatest effect. The authors present the surgical, radiotherapeutic, and chemotherapeutic results achieved hitherto in the treatment of the locally advanced carcinoma of the pancreas. Further possibilities for the future use of radiotherapy are proposed in order to encourage the establishment and application of interdisciplinary therapy conceptions.     

生物学系统内检测自由基方法的研究进展及其意义

活性氧等自由基与神经变性性疾病、糖尿病、辐射损伤等多种病理过程的发展相关.检测自由基技术在辐射防护和辐射生物效应方面具有重要的实际意义.该文综述了建立在电子自旋共振(ESR)基础上的各种自由基检测技术,同时介绍了新近建立的利用免疫电子自旋捕捉技术检测DNA和蛋白质大分子自由基的方法.     

Exercise-induced muscle damage and adaptation

Novel, unaccustomed exercise has been shown to result in temporary, repairable skeletal muscle damage. After exhaustive endurance exercise, muscle damage can be produced by metabolic disturbances associated with ischaemia. Extensive disruption of muscle fibres also occurs after relatively short term eccentric exercise where high mechanical forces are generated. Biopsies taken after repetitive eccentric muscle actions have revealed broadening, streaming and, at times, total disruption of Z-discs. Muscles that develop active tension eccentrically also become sore, lose inherent force-producing capability, and show a marked release of muscle proteins into the circulation. Because creatine kinase (CK) is found almost exclusively in muscle tissue, it is the most common plasma marker of muscle damage. Despite the universal use of CK as a marker, several factors with regard to efflux and clearance remain unexplained. Also the large intersubject variability in response to exercise complicates its interpretation. Damage progresses in the postexercise period before tissues are repaired. However, the mechanism to explain exercise-induced muscle damage and repair is not well defined. Among the factors that may influence the damage and repair processes are calcium, lysosomes, connective tissue, free radicals, energy sources, and cytoskeletal and myofibrillar proteins. Physical conditioning results in an adaptation such that all indicators of damage are reduced following repeated bouts of exercise. Recently, investigators have suggested that the prophylactic effect of training may be due to performance of a single initial exercise bout. Following a second bout of exercise performed 1 to 6 weeks after the first bout, there is a reduction in morphological alterations and performance decrements and a profoundly reduced elevation in plasma CK levels. Several hypotheses have been presented to explain the repeated bout or rapid training effect. Stress-susceptible fibres may be eliminated or susceptible areas within a fibre may undergo necrosis and then regenerate. These regenerated fibres, along with adaptations in the connective tissue, may provide greater resistance to further insult.     

Experiences with intraoperative radiotherapy in gastric carcinoma (Berlin method)

The aim of our pilot study is to determine whether intraoperative radiotherapy in gastric cancer cannot only prevent a local relapse but also improve the survival rate. Since November 1987, 26 patients with resectable gastric cancer were irradiated intraoperatively with the linear accelerator using fast electrons (single dose: 12 to 16 Gy). Percutaneous radiotherapy was performed postoperatively with 24 to 38 Gy (4 x 2 Gy per week). For intraoperative and percutaneous radiotherapy the target absorbed dose was selected in a way that their combined effect on the tumor was approximately equivalent to that of a total dose of 60 Gy in the usual fractionating. Up to now, the median survival time for stage III patients (UICC 1987) has been twelve months. In five patients who died of a relapse or of peritoneal carcinosis, histologic evaluation revealed in every case a diffuse tumor type according to Lauren-classification. All relapses occurred within the first eight months. The two-year survival rate according to Kaplan-Meier is 67% for stage III. Advanced resectable gastric cancer of the intestinal tumor type seems to profit from adjuvant intraoperative radiotherapy. The results warrant further research within the framework of a prospective randomized multicenter study.     

细胞焦亡信号通路在放射损伤中的研究进展

细胞焦亡是一种炎症性的程序性细胞死亡;与凋亡不同,细胞焦亡时总伴随着炎症反应。研究发现,细胞焦亡与多种疾病的发生、发展密切相关。在放射治疗引起的放射损伤中,细胞焦亡也发挥着重要作用。电离辐射使得细胞内的DNA断裂,产生氧自由基,而两者正是细胞焦亡良好的诱导剂。因此,本文从细胞焦亡的信号通路入手,综述了细胞焦亡在放射损伤中的研究进展,以期为减弱或阻断放射损伤提供新的思路。     

Comparison of the effects of real-time propulsive force versus limb angle gait biofeedback on gait biomechanics

BackgroundReduced forward propulsion during gait, measured as the anterior component of the ground reaction force (AGRF), may contribute to slower walking speeds in older adults and gait dysfunction in individuals with neurological impairments. Trailing limb angle (TLA) is a clinically important gait parameter that is associated with AGRF generation. Real-time gait biofeedback can induce modifications in targeted gait parameters, with potential to modulate AGRF and TLA. However, the effects of real-time TLA biofeedback on gait biomechanics have not been studied thus far.Research questionWhat are the effects of unilateral, real-time, audiovisual trailing limb angle biofeedback on gait biomechanics in able-bodied individuals?MethodsTen able-bodied adults participated in one session of treadmill-based gait analyses comprising 60-second walking trials under three conditions: no biofeedback, AGRF biofeedback, and TLA biofeedback. Biofeedback was provided unilaterally to the right leg. Dependent variables included AGRF, TLA, ankle moment, and ankle power. One-way repeated measures ANOVA with post-hoc tests were conducted to determine the effect of the biofeedback conditions on gait parameters.ResultsCompared to no biofeedback, both AGRF and TLA biofeedback induced significant increases in targeted leg AGRF without concomitant changes to the non-targeted leg AGRF. Targeted leg TLA was significantly larger during TLA biofeedback compared to AGRF biofeedback. Only AGRF biofeedback induced significant increases in ankle power; and only the TLA biofeedback condition induced increases in the non-targeted leg TLA.SignificanceOur novel findings provide support for the feasibility and promise of TLA as a gait biofeedback target. Our study demonstrates that comparable magnitudes of feedback-induced increases in AGRF in response to AGRF and TLA biofeedback may be achieved through divergent biomechanical strategies. Further investigation is needed to uncover the effects of TLA biofeedback on gait parameters in individuals with neuro-pathologies such as spinal cord injury or stroke.