The time course of radioprotection by WR 2721 in mouse skin

The radioprotective effect of 400 mg/kg of WR 2721 on mouse skin has been investigated over a series of times from 5 to 60 minutes after intravenous or intraperitoneal injection of the drug. The acute desquamation reaction on the hind leg of white mice was studied. Dose response curves were obtained for the average reaction over 15 to 25 days after single-dose irradiation. A high dose-rate electron beam (13–17 Gy/min) was used to minimize the irradiation time. Single doses of 20 to 60 grays were given. Dose modifying factors (DMFs) of 1.7-2.1 were obtained at 30 to 60 minutes, but only 1.1 to 1.3 at 5 minutes and intermediate values at 10 and 15 minutes. DMFs rose slightly faster and to slightly higher values after i.v. than after i.p. injection of WR 2721. We conclude that 30 minutes is the shortest interval which should be used between injection of WR 2721 and irradiation with this normal tissue.     

Measurement of WR-2721, WR-1065, and WR-33278 in plasma

Alkaline phosphatase was used in developing two new assays for WR-2721; one involved simple spectrophotometric titration with Ellman's reagent and the other was based upon HPLC analysis of a monobromobimane derivative. Both methods gave acceptable results when applied to whole plasma. Assays for WR-1065 and disulfide forms of the drug were also developed but were found to give unreliable results with whole plasma owing to apparent rapid reaction of these drug forms with plasma constituents. The methods were applied to the analysis of blood samples in rat 0-70 min after i.v. injection of WR-2721.     

Genistein treatment protects mice from ionizing radiation injury

The radioprotective and behavioral effects of an acute administration of the isoflavone genistein (4',5,7-trihydroxyflavone) were investigated in adult CD2F1 male mice. Mice were administered a single subcutaneous (s.c.) dose of genistein either 24 h or 1 h before a lethal dose of gamma radiation (9.5-Gy of cobalt-60 at 0.6 Gy min(-1)). Mice received saline, PEG-400 vehicle or genistein at 3.125, 6.25, 12.5, 25, 50, 100, 200, or 400 mg kg(-1) body weight. For mice treated 24 h before irradiation there was a significant increase in 30-day survival for animals receiving genistein doses of 25 to 400 mg kg(-1) (p<0.001). In contrast, the 30-day survival rates of mice treated with genistein 1 h before irradiation were not significantly different from those of the vehicle control group. Additionally, the acute toxicity of genistein was evaluated in non-irradiated male mice administered a single s.c. injection of saline, vehicle, or genistein at 100, 200 or 400 mg kg(-1). At these genistein doses there were no adverse effects, compared with controls, on locomotor activity, grip strength, motor coordination, body weight, testes weight, or histopathology. These results demonstrate that a single s.c. administration of the flavonoid genistein at non-toxic doses provides protection against acute radiation injury.     

E838对造血组织的放射防护作用

Ｅ８３８是一种新型放射防护剂，为炔雌醇衍生物。小鼠照射８Ｇｙ前第３、２、１天连续口服或腹腔注射Ｅ８３８０．２５μｇ／０．２ｍｌ，结果显示Ｅ８３８对受照小鼠ＣＦＵ－Ｓ（脾集落生成单位）和ＢＭＮ（骨髓有核细胞数）有明显的保护作用（经统计学处理差异有显著性）。为临床应用Ｅ８３８治疗放疗、化疗患者的白细胞减少症提供了依据     

Quantum dots and nanoparticles for photodynamic and radiation therapies of cancer

Semiconductor quantum dots and nanoparticles composed of metals, lipids or polymers have emerged with promising applications for early detection and therapy of cancer. Quantum dots with unique optical properties are commonly composed of cadmium contained semiconductors. Cadmium is potentially hazardous, and toxicity of such quantum dots to living cells, and humans, is not yet systematically investigated. Therefore, search for less toxic materials with similar targeting and optical properties is of further interest. Whereas, the investigation of luminescence nanoparticles as light sources for cancer therapy is very interesting. Despite advances in neurosurgery and radiotherapy the prognosis for patients with malignant gliomas has changed little for the last decades. Cancer treatment requires high accuracy in delivering ionizing radiation to reduce toxicity to surrounding tissues. Recently some research has been focused in developing photosensitizing quantum dots for production of radicals upon absorption of visible light. In spite of the fact that visible light is safe, this approach is suitable to treat only superficial tumours. Ionizing radiation (X-rays and gamma rays) penetrate much deeper thus offering a big advantage in treating patients with tumours in internal organs. Such concept of using quantum dots and nanoparticles to yield electrons and radicals in photodynamic and radiation therapies as well their combination is reviewed in this article.     

知信行模式下医院非放射工作人员电离辐射安全认知效果评价

目的 分析研究"知信行"模式对医院非放射工作人员核及辐射防护知识培训宣教的影响,为医院不同科室与临床核医学科高效协作及管理提供参考。方法 选取对临床核医学诊断受检者有密切接触的非放射工作人员,于培训及行政管理干预前后分别进行问卷调查,问卷是根据健康教育知识、信念、行为（KABP）模型自行设计,内容包括核与辐射的基本知识、放射性核素的特性及应用、电离辐射的医用防护和核与辐射的监管四大方面。对问卷的评分采用赋值法进行数据分析比较。结果 知信行模式宣教及干预后各相关工作人员的核及辐射防护相关知识得分均高于培训前,差异具有明显的统计学意义（P<0.01）。结论 开展放射防护知识培训宣教及科研活动,能有效改善和核素受检者有密切接触工作人员的知信行能力,同时,还应当重视加强管理部门的干预。     

Sodium selenite is a potent radioprotector of the salivary glands of the rat: acute effects on the morphology and parenchymal function during fractioned irradiation

In vitro studies show that sodium selenite is a potential radioprotector in normal cultural cells, but not in tumor cells. The aim of this study was to evaluate the cytoprotective potency of sodium selenite during a conventional fractioned irradiation of the salivary glands of rats. The head and neck area of male WAG/RijH rats was irradiated with ⁶⁰Co- rays (60 Gy/30 fractions/6 weeks). Sodium selenite (15 µg/kg body weight) was applied through a venous port 30 min before irradiation. Rats of a control group were treated in the same manner with an equal volume of physiologic sodium chloride. In the course of treatment, the salivary glands were resected at different stages and examined histopathologically. The evaluation of gland function was performed prior to and after radiotherapy by sialoscintigraphy. The irradiation caused dose-dependent damage in the salivary glands. Intra- and intercellular edema (16 Gy), vacuolization (30 Gy), degranulation (46 Gy) and necrosis of the acinar cells (60 Gy) occurred. Sodium selenite delayed the development of the described damage; additionally, the number of necrotic acinar cells after the application of 60 Gy was reduced (control, 75% vs. sodium selenite, 30%). The sialoscintigaphical results confirmed these results: the loss in gland function in the control group was 74 vs. 44% (P<0.05) in the sodium selenite group. Based on the morphological and sialoscintigraphical findings, a cytoprotective effect on the acute toxicity of the salivary glands of rats could be detected during irradiation with synchronous application of sodium selenite.     

鲨鱼软骨粘多糖对雄性小鼠免疫及生殖器官的辐射防护作用

目的 观察鲨鱼软骨粘多糖对γ射线损伤雄性小鼠免疫器官及生殖器官的保护作用。方法 将50只雄性小鼠随机分为正常对照组、模型组及低(0.5g/kg·d)、中(1.0g/kg·d)、高(2.0g/kg·d)三个剂量鲨鱼软骨粘多糖组,每天一次灌胃给药,给药体积为0.4ml/20g,灌胃2周后,除正常对照组外,各组均以剂量率为0.83Gy/h的⁶⁰Coγ射线进行一次全身照射,照射剂量为5Gy。于辐照前1d,辐照后3d、14d测定小鼠体重、外周血白细胞数,辐照后14d测定小鼠胸腺指数,脾指数,骨髓有核细胞计数、睾丸重量指数,精子总数及精子畸形率。结果 鲨鱼软骨粘多糖可使辐照后3d中、高剂量组小鼠外周血白细胞数明显高于模型组(P<0.05),辐照后14d,中、高剂量组小鼠的胸腺指数、骨髓有核细胞数及精子总数明显高于模型组(P<0.05),高剂量组小鼠的脾指数及睾丸重量指数显著高于模型组(P<0.05),中、高剂量组的精子畸形率显著低于模型组(P<0.01)。结论 鲨鱼软骨粘多糖对辐射损伤小鼠的免疫器官及生殖器官具有一定的保护作用。     

64排CT骨盆低剂量扫描技术的探讨

目的探讨不同管电流值对64排CT骨盆低剂量扫描图像质量的影响,获取较佳的低剂量扫描方案。方法随机选取50名志愿者进行64排CT骨盆扫描,随机分成5组,每组10名,管电流设定值分别为250mA、150mA、100mA、50mA和30mA,其他扫描参数不变。扫描时分别测量辐射剂量值,并对原始图像及重组图像进行评分。统计分析不同的管电流值扫描的辐射剂量和图像质量。结果管电流为250mA、150mA和100mA的骨盆图像中,软组织的图像质量评分无统计学差异,50mA和30mA的图像质量评分低于与250mA的图（P〈0.05）。不同管电流值的骨组织显示质量评分无统计学差异（P〉0．05）;本组实验得到骨盆64排CT低剂量扫描管电流的最低值是30mA,单纯将管电流由标准250mA降至低30mA时,患者所接受的平均辐射剂量由14．7mGy降至1．8mGy。结论不同管电流值对软组织图像显示质量的影响较骨组织明显,应根据要重点观察的组织来选择适当的扫描方案进行64排CT骨盆低剂量扫描。     

Mitigation of radiation-induced optic neuropathy in rats by ACE inhibitor ramipril: importance of ramipril dose and treatment time

Purpose Radiation-induced optic nerve damage was reduced by ramipril, a prodrug angiotensin-converting enzyme inhibitor (ACEI). This study was to determine the optimum dose and administration time of ramipril for mitigating radiation-induced optic neuropathy. Materials and method Adult Fischer 344 male rats were treated with a single dose radiation 30 Gy by using radiosurgical technique. After irradiation, the animals were randomly assigned into groups of different ramipril doses and administration time; control (no treatment), radiation alone, radiation + ramipril in different doses and starting times of drug. Ramipril was given 0.5–1.5 mg/kg/day and AT1R blocker Losartan 20 mg/kg/day in drinking water for 180 days. Functional endpoint with visual evoked potential (VEP) and anatomical endpoint with gross and histological analysis with immunohistochemical (IHC) stain were used. Results Normal VEP measurements in un-irradiated rats were 46.2 ± 7.9 ms. There was no change of VEP value until 4 months, but was lengthened to 188.1 ± 58.7 ms at 6 months after radiation. By ramipril treatment with the dose of 1.5 mg starting at 2 weeks after radiation, VEP was significantly shortened to 105.7 ± 88.5 ms at 6 months. Gross and microscopic structure of the irradiated optic nerve was well preserved in the ramipril-treated group. Conclusion Ramipril can mitigate the radiation-induced optic nerve damage and preserve the functional integrity of the nerve. The results support early treatment with a high dose of ramipril after radiation.