Sterilization of bone allografts by microwave and gamma radiation

Abstract Purpose: Bone allografts are used to enhance healing in osteotomies, arthrodesis, fractures and to replace bone loss resulting from tumour or trauma. However, a major concern associated with the bone allografts is the potential for disease transmission. Various sterilization techniques have been developed to prevent infection through allografts. This study was undertaken with the aim of exploring the use of microwave radiation for sterilization of bone allografts and to compare with gamma radiation sterilization. Materials and methods: Bone allografts were processed from femoral heads obtained from living donors. The effect of microwave and gamma radiation on the bacteria isolated from bone allograft was evaluated. The microwave radiation treatment was performed at 2450 MHz (frequency) for varying lengths of time at maximum power 900 Watts (W). Viability of three Gram-positive bacteria - Bacillus subtilis, Corynebacterium, Staphylococcus aureus and three Gram-negative bacteria - Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was examined after irradiation of bacterial suspensions and contaminated processed bone allografts. The sterility test of microwave and gamma irradiated bone allograft was carried out in accordance with ISO (International Organization for Standardization) 11737-2. Results: Microwave irradiation (2450 MHz and 900 W) of bacterial isolates resulted in complete inactivation within 60 seconds. The contaminated bone samples showed no growth of organisms after 2 minutes of exposure to microwave irradiation. No viable counts were detected in bone grafts inoculated with Gram-negative bacterial species on gamma irradiation to a dose of 15 kGy. Bones contaminated with Gram-positive bacteria required a higher dose of 20 kGy for complete inactivation. Conclusions: The study shows that sterilization of contaminated femoral head bone allografts can be achieved by short exposure of 2 min to 2450 MHz and 900 W microwave radiation.     

微波辐射合成藜芦醛条件的探讨

目的探讨微波辐射合成藜芦醛的适宜条件。方法分别以180,260,340,420W的微波及2,3,4,5,6,7,8min的辐射时间观察藜芦醛的收率,并与传统油浴加热法进行比较。结果微波辐射功率260W时收率最佳且比较稳定,该功率下最佳反应时间为5min;与普通油浴法比较微波辐射法具有收率高、耗时短、反应完全等优点。结论微波辐射法制备藜芦醛反应时间短、收率高、反应完全;微波辐射的最佳条件为功率260W,时间5min。     

Responses of the bacterial community to chronic gamma radiation in a rice paddy ecosystem

Purpose:?Public concern about radiation protection of the environment and non-human species is increasing. The potential impact of chronic gamma radiation on the bacterial community in a rice paddy ecosystem was investigated.

Materials and methods:?Paddy field microcosm samples were continuously exposed at a dose rate of 1 Gy day^?1 for five days after which the bacterial community structures in them were compared with those of unirradiated control samples by denaturing gradient gel electrophoresis (DGGE) of the 16S ribosomal ribonucleic acid (rRNA) gene. Dissolved ions in ponding waters of the microcosm samples were determined by ion chromatography.

Results:?The DGGE band profiles were clearly different between the control and exposure samples. Sequencing of selected DGGE bands revealed that a specific species of the genus Clostridium and of the genus Massilia were grown under radiation exposure. Additionally, the concentrations of sulphate ion in the ponding water of the microcosm samples increased under radiation exposure. Concentrations of Na⁺, Ca²⁺, and F^? inversely decreased.

Conclusions:?The data presented suggest that chronic gamma radiation affects the bacterial community structure and material cycles in the rice paddy ecosystem.     

电磁辐射和微波的生物学效应

电磁辐射广泛存在于人类的生存环境之中。人们在利用电磁辐射和微波为人类的健康服务的同时,也越来越多地认识到其对健康的危害。目前电磁辐射已成为损伤人类健康的最主要物理因素之一。本文综述了近年来电磁辐射和微波的生物学机制、对人体各组织器官的不良影响、研究中存在的问题以及研究方向。     

脉冲微波生物效应实验辐射场特性研究

目的：建立脉冲微波辐射场特性参数的检测与评价方法，为剂量学和生物效应研究提供基础数据。方法：采用二极管检波技术，实现辐射场峰值功率密度的测量和监测。结果和结论：给出了照射点的峰值功率密度、监测值与实测值之间的拟合公式、时域和频域波形、峰值稳定性和场均匀性等参数。     

阿的平对微波辐射小鼠海马损伤的保护作用

目的探讨预先给予阿的平（quinacrine）对微波辐射致小鼠脑损伤的保护作用。方法小鼠随机分为4组,即正常组、辐射对照组、阿的平低剂量组（12.6 mg/kg）、阿的平高剂量组（50.4 mg/kg）。接受辐射动物于照射后即刻（0 d）,1,2,7 d后完成检测,正常组动物在辐射实验后7 d后完成检测。微波辐照后,于不同时间点提取小鼠的脑组织蛋白,检测脑组织中HSP70蛋白表达变化。结果脑组织蛋白表达检测显示,微波辐射后1 d,辐射对照组小鼠脑中HSP70蛋白的表达开始升高,直至7 d。阿的平两个剂量组0,1,7 d给药组与辐射对照组相比明显上调,高剂量组尤甚。辐射对照组小鼠大脑海马的病理切片显示细胞水肿、血管扩张肿胀、间质充血等损伤,并出现海马沟回组织松散、细胞核皱缩、细胞水肿、空泡现象。预先灌胃给予小鼠阿的平后,小鼠脑组织的病理损伤有所减轻,状况有所改善。结论阿的平的这些保护机制可能与其上调HSP70蛋白表达发挥抗炎和抗凋亡作用,降低微波辐照引起的组织、细胞炎症反应和凋亡、坏死有关。     

Effect of gamma radiation on the structural and biological properties of Angiotensin II

Purpose: The vasoactive octapeptide hormone angiotensin II (DRVYIHPF, AngII) was selected as the target of this2investigation, which was aimed at determining the effect of gamma radiation on peptide structure and biological activity.

Materials and methods: Radiation doses ranging from 1–15 kGy were applied to samples of purified AngII.

Results: The measured amount of remaining native hormone decreased non-linearly as the gamma radiation dose increases. Amino acid analysis of these irradiated peptide solutions demonstrated similar, simultaneous modifications of Phe⁸ and His⁶ residues along with the increase in the radiation dose. This structural variation of the vasoactive peptide closely resembled the decreasing process of the biological potencies of irradiated peptide solutions in rat uterus and guinea pig ileum muscle preparations.

Conclusions: These findings suggest that investigating the effect of gamma radiation on small model molecules such as peptides could be of value for further extending this type of study to other physiologically relevant macromolecules such as proteins. Of note, this unique approach could also be useful in generating different types of peptide analogs (after purification) for application in future classical structure-function studies.     

微波辐射生物效应的量效关系研究进展

微波技术广泛应用于家庭、工业、通信、医疗和军事等方面，其对人体的危害也越来越受重视。本文对微波辐射后神经、内分泌、心脏和生殖等方面损伤的量效关系进行了综述。     

高功率微波辐射损伤防护药物研究进展

随着科技的进步,微波被广泛运用到各个领域,给人类带来便利的同时,其潜在的健康损害普遍受到各国政府和科研人员的关注。高功率微波（ high power microwave ,HPM）在高新技术武器和新概念武器中的应用,使得部队官兵暴露于HPM环境下的概率增加。已有研究明确证实,特定条件的微波辐射对神经系统、免疫系统、心血管系统以及生殖系统存在不同程度的损伤效应。因此,在做好物理防护的同时,积极有效的医学防护,对于减小HPM损伤效应、提高部队官兵作战能力具有重要的意义。该文针对微波辐射损伤效应的机制特点,对近年来微波辐射损伤防护药物的研究进展进行综述,为更加安全有效的新药研发提供依据。     

Statistical prediction of terrestrial gamma radiation dose rate based on geological features and soil types in Kota Tinggi district, Malaysia

A statistical prediction of terrestrial gamma radiation dose rate has been performed, covering the Kota Tinggi district of Peninsular Malaysia. The prediction has been based on geological features and soil types. The purpose of this study is to provide a methodology to statistically predict the gamma radiation dose rate with minimum surveying in an area. Results of statistical predictions using the hypothesis test were compared with the actual dose rate obtained by measurements.     

放烧复合伤诱导小鼠骨髓红细胞微核率的研究

探讨放烧复合伤条件下，小鼠骨髓嗜多染红细胞ＭＮ率（ｆＭＰＣＥ）用于估算辐射剂量的可能性。方法以ｆＭＰＣＥ为指标，实验分为单纯烧伤组（１０％，２０％），单纯放射组（１，３，５Ｇｙ），放烧复合伤组（１０％＋１，３，５Ｇｙ，２０％＋１，３，５Ｇｙ），研究ｆＭＰＣＥ在２４小时的量效关系。结果单纯烧伤组与空白对照组相比，ｆＭＰＣＥ均无明显增加，放烧复合伤各剂量组明显低于单放组，烧伤面积２０％放烧复合伤组又明显低于１０％放烧复合伤组。结论小鼠放射损伤复合烧伤后其骨髓ｆＭＰＣＥ呈降低趋势，研究还发现烧伤后小鼠骨髓新生红细胞（ＰＣＥ）比例有一定升高，这可能是造成放烧复合伤时ｆＭＰＣＥ降低的原因。     

Radiographic evaluation of the complications of long bone allografts

Purpose To study the long-term results of long bone allografts in patients with benign and malignant bone tumors.Material and Methods Forty patients for whom full clinical and radiological information was held were investigated in order to assess the overall incidence of complications including fractures, nonunion, hardware problems, infections, and bone resorption.Results There were four deaths; four more patients had distant metastases and one patient had a recurrent chondrosarcoma. Seventeen patients (42%) had either no complications (nine patients) or only minor ones (eight patients). Eleven patients (27%) sustained fractures of either their allograft (eight patients) or of their hardware (three patients). Hardware problems occurred in nine patients (22.5%), six of whom had serious problems requiring revision. The majority of the fractures and hardware problems occurred in younger male patients (82%). Infection occurred in five patients (12.5%), two of whom required revision, while two cases were superficial. Dissolution of the allograft occurred in 12 patients (30%), 7 of whom required removal of the allograft. Ten of these 12 patients were female.Conclusion The long-term survival of long bone allografts is not as good as generally reported if an adequate follow-up time period is used. Most of the fractures and hardware problems occurred in the younger active male patient, whose activities should probably be curtailed. Resorption of the allograft is another serious complication which appears to occur mainly in female patients and could possibly be controlled by chemotherapy.     

Engraftment of bone marrow-derived cells after nonlethal radiation in syngeneic C57BL/6 mice

Objective To study the characteristics of cell engraftment in mice at a lower dose under nonlethal radiated condition.Methods A syngeneic C57BL/6 mouse model,transplanted with 1 × 107 bone marrow cells...     

不同条件微波辐射致大鼠学习和记忆能力及脑组织结构改变的影响研究

目的探讨微波单次和累积辐射对大鼠学习和记忆能力以及脑组织结构的影响。方法对80只二级SD大鼠采用单次和累积辐射,单次辐射平均功率密度分别为2 mW/cm2和11 mW/cm2,累积辐射组每天辐射,平均功率密度为4.68μW/cm2,连续辐射30 d。采用Morris水迷宫观察大鼠学习与记忆能力的改变,于辐射后1,7,14,30,60 d采用光镜和电镜观察大鼠脑组织学和超微结构的改变。结果 （1）单次辐射后,与正常对照组相比,各辐射组大鼠逃避潜伏期均在辐射后有不同程度延长。2 mW/cm2组辐射后1 d和2 d,大鼠逃避潜伏期差异有显著性,11 mW/cm2组辐射后1 d和3 d,逃避潜伏期有显著性差异。累积辐射后大鼠逃避潜伏期无显著性差异。（2）11 mW/cm2组辐射后7~14 d,大鼠海马和大脑皮质神经元皱缩,核固缩,线粒体肿胀,局部空化,内质网扩张,突触间隙不清、囊泡减少,血管内皮连接增宽;累积辐射后14 d,大鼠海马及大脑皮质神经元固缩,线粒体肿胀空化,内质网扩张,突触间隙不清。结论 2和11 mW/cm2微波单次辐射可使大鼠学习和记忆能力下降,大鼠脑组织结构损伤;4.68μW/cm230 d微波累积辐射可引起大鼠脑组织结构损伤。     

骨髓间充质干细胞移植治疗犬急性放射性肠病临床观察

目的建立比格犬急性放射性肠病的损伤模型,观察骨髓间充质干细胞移植治疗犬急性放射性肠病的临床效果。方法将35只比格犬随机分为空白对照组(A组)、10 Gy单独照射组(B组)、12 Gy单独照射组(C组)、14 Gy单独照射组(D组)、10 Gy照射后干细胞治疗组(E组)、12 Gy照射后干细胞治疗组(F组)及14 Gy照射后干细胞治疗组(G组),每组5只。对比格犬腹部进行X线调强照射,观察单独照射、照射后干细胞治疗的比格犬的临床特点、肠镜表现、生存时间,并采用组织病理学评分对放射造成的肠损伤程度进行评估。结果比格犬肠损伤程度与放射剂量呈正相关。E、F组干细胞治疗后肠损伤组织病理学评分明显低于治疗前(P<0.05);G组治疗前后比较,差异无统计学意义(P>0.05)。比格犬生存时间与放射剂量呈负相关。F组生存时间明显长于C组(P<0.05);E组与B组、G组与D组比较,差异无统计学意义(P>0.05)。结论随着放射剂量增大,比格犬急性放射性肠病加重,生存时间缩短。骨髓间充质干细胞移植在12 Gy剂量的急性放射性肠病的治疗中发挥积极作用。     

宫颈癌术后限定骨髓剂量盆腔调强放疗的临床研究

目的 观察宫颈癌患者术后限定骨髓剂量的盆腔调强放疗(BMS-IMRT)与非限定骨髓剂量的盆腔调强放疗(IMRT)联合化疗的近期疗效及不良反应。方法 本院宫颈癌术后患者70例,用抽签方法随机分为BMS-IMRT组34例和IMRT组36例,行盆腔外照射调强放疗联合化疗,计划靶体积剂量45 Gy分25次。BMS-IMRT组勾画骨盆并给予单独限量:骨盆V₃₀≤50%;70例患者同期每周40 mg/m²顺铂化疗。结果 除3例因重度骨髓抑制未完成化疗外,67例患者顺利完成治疗。两组2年的局部控制率及生存率、下消化道及泌尿系统不良反应差异无统计学意义,BMS-IMRT组血液学不良反应较IMRT组轻,差异有统计学意义(χ²=14.355,P<0.05)。结论 宫颈癌术后行盆腔同步放化疗患者,BMS-IMRT组较IMRT组血液学不良反应减轻,近期疗效及其他放疗不良反应无明显差异。     

高功率微波源的改建及其测试系统的建立

目的：为高功率微波辐射致伤效应及其机制的研究提供可靠技术保障。方法：设计并制作垂直辐照天线和辐照平台。并建立测试系统。结果：微波源性能稳定，并具有垂直和水平线双向辐射及功率密度可调的功能，测试结果客观、科学和准确。结论：所改建高功率微波源可适合不同功率密度、不同动物乃至离体细胞的生物学效应研究。     

新鲜同种与异种骨移植免疫反应的比较研究

目的　通过比较新鲜同种与异种骨移植免疫反应 ,探讨异种骨移植排斥机制。　方法　取C57BL/ 6小鼠 10只和新西兰兔 1只分别为新鲜同种和异种骨供体。取 40只BALB/c小鼠为骨移植受体 ,随机分为A、B两组 (每组 2 0只 ) ,分别在其股后肌袋植入新鲜同种和新鲜异种骨。分别于术后 1,2 ,4,6周分批取材检测。通过观察术后受者的淋巴细胞刺激指数、淋巴细胞亚群分析、细胞因子产生及组织学表现 ,比较新鲜同种与异种骨移植免疫反应。　结果　新鲜异种骨移植在早期细胞刺激反应较强 (P <0 .0 5,0 .0 1) ,后期减弱。早期其CD4 T细胞亚群并不比同种组低 ,但 2周时CD4 T细胞和CD4/CD8比值均明显降低。细胞因子检测显示 ,早期异种组的IL -2分泌较同种组多 (P <0 .0 5) ,后期减少 ,而且IFN -γ分泌少 (P <0 .0 1) ,IL -4分泌多 (P <0 .0 5,0 .0 1)。组织学检查发现 ,异种组细胞浸润多 ,且以单核、巨噬细胞为主。　结论　新鲜同种与异种骨移植排斥机制不同 ,异种排斥早期强、后期弱 ,早期以Th2反应为主 ,而同种排斥以Th1反应为主     

微波辐射损伤及防护研究进展

随着微波技术广泛应用于通讯、广播、工业电器设备、医疗及家用电器等,其可能带来的生物危害及环境污染越来越引起人们的重视。对微波辐射生物学效应、机制和防护研究已成为各国学者的研究热点且已取得一定进展。本文就微波辐射对生物体健康的影响、生物效应机制及辐射防护进展作一综述。