The effect of single and repeated UVB radiation on rabbit cornea

Background Cumulative effect of ultraviolet radiation (UVR) is an important aspect of UV corneal damage. The purpose of this study was to apply high resolution magic angle spinning proton nuclear magnetic resonance (HR-MAS ¹H NMR) spectroscopy to evaluate the effect of single and repeated UV radiation exposure of the same overall dose on the rabbit cornea.Methods Corneal surfaces of 24 normal rabbit eyes were examined for the effects of UVB exposure (312 nm). In the first group (UVB1), animals were irradiated with a single dose (3.12 J/cm²; 21 min) of UVB radiation. The animals in the second group (UVB2) were irradiated three times for 7 min every other day (dose of 1.04 J/cm²; days 1, 3, 5) to give the same overall dose (3.12 J/cm²). The third group served as an untreated control group. One day after the last irradiation, the animals were sacrificed, and the corneas were removed and frozen. HR-MAS ¹H NMR spectra from intact corneas were obtained. Special grouping patterns among the tissue samples and the relative percentage changes in particular metabolite concentrations were evaluated using modern statistical methods (multivariate analysis, one-way ANOVA).Results The metabolic profile of both groups of UVB-irradiated samples was significantly different from the control corneas. Substantial decreases in taurine, hypo-taurine and choline-derivatives concentrations and substantial elevation in glucose and betaine levels were observed following the UVR exposure. There was no significant difference between the effect of a single and repeated UVB irradiation of the same overall dose.Conclusions For the first time, the effects of single and repeated UVR doses on the metabolic profile of the rabbit cornea were analysed and compared. The combination of HR-MAS ¹H NMR spectroscopy and modern statistical methods (multivariate analysis, one-way ANOVA) proved suitable to assess the overall view of the metabolic alterations in the rabbit corneal tissue following UVB radiation exposure.     

Fas、Bcl-2在γ射线体外诱发的白血病小鼠骨髓细胞中的表达

目的 :观察 Fas、Bcl- 2在 γ射线体外诱发的急性淋巴细胞白血病小鼠骨髓细胞中表达情况 ,以探讨辐射致癌的机制。方法 :采用 4次 1.75 Gyγ射线全身照射 BAL B/ c小鼠诱发白血病模型 ,通过流式细胞仪对照射后白血病组、未癌变组及对照组小鼠骨髓细胞中 Fas、Bcl- 2的表达进行检测 ;应用抗 Fas抗体诱导细胞凋亡 ,进一步观察 Fas、Bcl- 2的表达对骨髓细胞凋亡的影响。 结果 :白血病小鼠骨髓细胞 Fas表达较未癌变组及对照组明显下降 (P<0 .0 1) ,而 Bcl- 2的表达明显增强 (P<0 .0 1) ;白血病小鼠骨髓细胞明显耐受抗 Fas抗体诱导的细胞凋亡。 结论 :Fas低表达、Bcl- 2高表达导致了细胞凋亡受到抑制 ,这可能是辐射引起小鼠急性淋巴细胞白血病的机制之一。     

~(60)Coγ射线照射诱发小鼠恶性肿瘤

目的：建立γ射线诱发小鼠恶性肿瘤动物模型。方法：BALB／c小鼠经^60Coγ射线全身照射，每次吸收剂量1．75Gy，吸收剂量率0．88Gy／min，每周1次，共4次。照后每隔1～2个月处死一批小鼠，分别取胸腺、肺脏、肝脏、脾脏、肾脏、胃、生殖腺、肠系膜、盲肠、大脑等组织器官，甲醛溶液固定后进行病理学检查及裸鼠致瘤实验。结果：照后15个月BALB／c小鼠出现的肿瘤类型以白血病为主，并发现汗腺瘤及恶性卵黄囊瘤；白血病经病理学证实为淋巴细胞型白血病；白血病及汗腺瘤的裸鼠致瘤实验已稳定连续传至第12代。结论：成功建立^60Coγ射线体外诱发的小鼠恶性肿瘤动物模型。     

放射性~(125)I粒子组织间植入对家兔尿道损伤的实验研究

目的:研究不同剂量的放射性125I粒子对家兔尿道的放射性损伤。方法:麻醉下将放射性125I粒子植入雄性家兔尿道旁1.0cm处。125I粒子的放射性粒子活度分别为14.8MBq(A组)、29.6MBq(B组)和44.4MBq(C组),对照组(D组)仅尿道旁种植相当于粒子大小无放射性的无菌铅管1粒。植入后4周,摄尿道片,观察粒子位置等情况;原手术切口切开,取放射粒子周围2.0cm范围内的家兔尿道组织作肉眼、光学显微镜和电子显微镜观察,进行放射性损伤的评价。结果:术后4周,肉眼及光学显微镜观察,实验组与对照组粒子周围的尿道粘膜、粘膜下及肌层所见基本一致;C组少部分电镜视野中观察到尿道上皮胞质出现较多空泡变性、空化、嵴稀疏等超微结构的损伤。光镜下尿道入射性损伤评分,A、B、C、D组分别为(2.20±0.18)、(2.23±0.15)、(2.27±0.10)、(2.10±0.17)分,A、B、C组与D组相比,差异无显著性(P>0.05)。对线粒体作FlaMeng半定量分析,A、B、C、D各组评分分别为(1.23±0.13)、(1.34±0.25)、(1.41±0.30)、(1.12±0.13)分,A、B、C各组与D组(对照组)相比,差异无显著性(P>0.05)。结论:放射性125I粒子对尿道放射性损伤随粒子的放射性活度的增加而逐渐加重,呈明显的放射性活度效应关系;正常剂量的放射性粒子对尿道的损伤是很轻微的,是安全可行的。     

^125I放射微粒微创植入治疗前列腺癌

目的观察^125I放射微粒植入对前列腺癌的治疗效果。方法对26例临床确诊为前列腺癌患者经皮穿刺在癌组织植入^125I放射微粒，每例平均36粒，术后复查肛诊、B超、影像学及血生化指标。结果患者植入治疗经过顺利，2例少量出血，留置导尿后愈合，3个月后经肛诊、直肠B超示结节缩小，前列腺特异性抗原（PSA）降低，多普勒超声显示结节内动脉收缩期最大血流速度（VS）、阻力指数（RI）及动脉搏动指数（PI）均明显下降。结论^125I放射微粒植入对前列腺癌的治疗安全性好、效果可靠。     

肿瘤物理治疗技术及设备

简要介绍了肿瘤的放射治疗和热治疗的技术及设备，介绍了各种技术及设备的特点。     

Data Bank and Consulting System for Medical Management of Patiens with Acute Radiation Sickness

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头低位模拟失重状态对前庭功能的影响

为研究头低位模拟失重对运动病症状、垂直视动眼震（ＶＯＫＮ）及体液重新分配的影响，在头低位－１０°的模拟失重状态下，采用大视野的垂直视动刺激，观察１８名正常人的运动病症状、ＶＯＫＮ、激素（ＡＶＰ、ＶＩＰ、ＣＯＲＴ、ＡＬＤＯ）的反应特点。结果表明，头低位－１０°状态下的大视野垂直视动刺激可以诱发出明显的运动病症状，头低位－１０°的垂直视动刺激比坐位更容易诱发运动病。坐位状态ＶＯＫＮ慢相速度有明显的方向性不对称，敏感组ＶＯＫＮ方向性不对称有显著差异（Ｐ＜０．０５）。头低位－１０°时ＶＯＫＮ的不对称现象不明显，向下方向运动的ＶＯＫＮ慢相速度显著增加。分析指出，头低位－１０°状态下垂直视动刺激比坐位和秋千刺激的贡献率大。尿中ＣＯＲＴ（皮质醇）在秋千和头低位的垂直视动刺激前后有显著性增加。提示：大视野的垂直视动刺激与头低位－１０°两种刺激的结合可能成为预测空间运动病的方法之一．     

壳聚糖辐射效应的研究（Ⅰ）──辐照剂量与分子量的关系及辐射裂解的G（S）值

通过粘度的测量，考察了壳聚糖在不同条件下经不同剂量γ射线辐照所引起的分子量的变化，并分别计算了真空和空气中壳聚糖辐射裂解的Ｇ（Ｓ）值。     

Genetic ecotoxicology I: DNA integrity and reproduction in mosquitofish exposed in situ to radionuclides

Female mosquitofish (Gambusia affinis) were collected from two sites located on the US Department of Energy's Oak Ridge Reservation that are contaminated with 137Cs, 90Sr, other radionuclides and chemical genotoxicants. Fish from non- radionuclide contaminated environments located off the reservation were also collected. DNA, extracted from liver tissue and blood cells, was examined by gel electrophoresis for structural damage in the form of strand breakage. In general, the level of DNA strand breaks was elevated in fish from radionuclide-contaminated sites with observed differences in the number and type of strand breaks between liver tissue and blood cells. The number of malformed embryos was higher in fish at the contaminated sites, and varied with season. Fecundity was negatively correlated with the level of double strand breaks in the DNA of fish from one contaminated site. Females with broods that included malformed embryos had more DNA strand breakage than those that did not; and furthermore, a threshold effect was observed between the occurrence of malformed embryos and the presence of double strand breaks in the DNA of the mother. These findings have implications for both ecological risk assessment and evolutionary ecology