微波辐射免疫比浊法加速测定免疫球蛋白

本文应用微波辐射免疫比浊法加速测定免疫球蛋白(IgG、IgA、IgM).结果表明:用本法测定的线性范围较宽:IgG从3.24～51.92/L;IgA从0.49～7.92g/L;IgM从0.36～5.75/L.批内、批间精密度(CV):IgG从44～7.4%;IgA从4.1～9.5%;IgM从4.0～8.8%.本法与传统免疫比浊法和进口试剂自动免疫比浊法(Monarch 2000)测定比较,其结果相关良好,r从0.950至0.996,P>0.05.本法的特点是操作简便、快速,可明显缩短抗原和抗体反应达到终点的时间.     

Deoxyribonucleic acid turnover in immature neurons of the rat cerebral cortex

To test for metabolic deoxyribonucleic acid (DNA) turnover in differentiating neurons, [methyl-3H]thymidine was injected into the lateral cerebral ventricles of newly born rats, and after 6, 24 and 96 h, neuronal nuclei were prepared from the immature cerebral cortex. Enzymatic treatment converted virtually all of the DNA into soluble deoxynucleosides which were fractionated by high-performance liquid chromatography for determination of specific activity. The specific activity of thymidine was found to decline rapidly with time. The rate of this loss correlated with the radioactivity initially incorporated into the DNA. This suggested that DNA was being replaced by DNA repair as a consequence of radiation damage, rather than by spontaneous metabolic DNA turnover.     

Local and systemic consequences of acute,low-dose ultraviolet B radiation are mediated by different immune regulatory mechanisms

Acute, low-dose ultraviolet B (UVB) radiation alters the local skin site such that epicutaneous application of hapten fails to induce contact hypersensitivity (CH), but induces tolerance in UVB-susceptible mice. Although the inability of irradiated skin to support CH induction may be a strictly local effect, there may also be systemic immune consequences of UVB radiation delivered in this manner. To examine this matter, abdominal skin of C57BL/6 mice was exposed to acute, low-dose UVB radiation. Dinitrofluorobenzene was immediately painted directly on the irradiated site, or at a distant (unirradiated) site. In separate experiments, epicutaneous application of the hapten on a distant site was delayed for 1–3 days. The mice were tested for acquisition of CH, and for tolerance, i.e. the capacity to become sensitized when exposed subsequently to hapten via normal body wall skin. It was found that, immediately after completion of the UVB regimen, CH was inducible via unirradiated, but not via irradiated, skin. At 3 days post-UVB exposure, CH was no longer inducible even through unirradiated skin. Mice that first encountered hapten via UVB-exposed skin developed tolerance, as did mice that first encountered hapten via unirradiated skin of UVB-treated mice. Neutralizing anti-tumor necrosis factor-α TNF-α antibodies failed (a) to restore the ability of unirradiated skin to support induction of CH, and (b) to interfere with tolerance induction, whether hapten was first painted on irradiated or unirradiates skin. The data indicate that the acute, low-dose regimen of UVB radiation produces effects on the immune system that are manifest locally as well as systemically. By demonstrating that the disruption of CH induction following UVB radiation is TNF-α dependent, whereas locally and systemically induced tolerance is not, our findings encourage further search for other UVB-related modulators of systemic immunity and tolerance.     

Environmental conditions and variation in levels of sun exposure among children in child care

Sun exposure in childhood is 1 of the risk factors for developing skin cancer, yet little is known about levels of exposure at this age. This is particularly important in countries with high levels of ultraviolet radiation (UVR) such as Australia. Among 49 children 3 to 5 years of age attending child care centers, UVR exposure was studied under 4 conditions in a repeated measures design; sunny days, cloudy days, teacher’s instruction to stay in the shade, and a health professionals instruction to apply sunscreen. Three different data collection methods were employed: (a) completion of questionnaire or diary by parents and researcher, (b) polysulphone dosimeter readings, and (c) observational audits (video recording). Results of this study indicated that more than half the children had been sunburnt (pink or red) and more than a third had experienced painful sunburn (sore or tender) in the last summer. Most wore short sleeve shirts, short skirts or shorts and cap, that do not provide optimal levels of skin protection. However, sunscreen was applied to all exposed parts before the children went out to the playground. Over the period of 1 hr (9–10 a.m.) the average amount of time children spent in full sun was 22 min. On sunny days there was more variation across children in the amount of sun exposure received. While the potential amount of UVR exposure for young children during the hour they were outside on a sunny day was 1.45 MED (Minimum Erythemal Dose), they received on average 0.35 MED, which is an insufficient amount to result in an erythemal response on fair skin even without the use of sunscreen.     

Radiation therapy for pancreatic cancer: eleven year experience at the JCRT

Radiation therapy (XRT) for 41 patients with unresectable pancreatic cancer resulted in a median survival of 7.0 months. There was no difference in median survival for patients receiving external beam alone (3500 to 5600 cGy) (n = 28), intraoperative (IORT) boost plus external beam (5040 to 6750 cGy) (n = 9), or a gold-198 implant +/- external beam radiation (n = 4). A pilot study using orthovoltage IORT boost indicates no acute toxicity with doses of 1250 to 1750 cGy. Serious late damage has not been observed in any patients followed to 2 years. Local recurrence in patients treated post-operatively after "radical" surgery occurred in one of 10 (10%). This adjuvant treatment is safe and appears to improve local control rates compared to historical data, but survival is still poor. The median survival for the post-operative group is 10 months; three patients are alive without disease 8 months to 8.3 years after treatment.     

No disturbance of myelination in the central nervous system by selective3Hβ-irradiation

Summary The effect of a selective irradiation of myelin by³H -particles was studied by light and electron microscopic methods in guinea pig spinal cord. The animals were injected with [³H]leucine shortly after birth when the rate of myelin biosynthesis is high and sacrificed 130 days later. In spinal cord the radioactivity was mainly preserved in myelin because the half life of myelin proteins is much higher than that of most other CNS protein. As a consequence the irradiation dose in the white matter was much higher than in the gray matter. In myelin internally irradiated by³H -particles within 130 days at a dose of 10 Gy no alterations could be detected either by morphological or by morphometric methods.Supported by the Deutsche Forschungsgemeinschaft     

探究4种临床CT扫描方式对受检者辐射剂量的影响及胸部扫描辐射场的空间分布

目的 探究4种临床CT扫描方式对受检者常见组织吸收剂量的影响及胸部扫描的辐射场空间分布,以期为受检者与机房内空间辐射防护提供依据。方法 利用热释光探测器（TLD）测量仿真体模的眼晶体、甲状腺、性腺、胸部和腹部皮肤在4种CT扫描方式下的吸收剂量。利用TLD监测胸部螺旋扫描时距离CT诊断床不同位置处的空气比释动能。结果 仿真体模的眼晶体、甲状腺、性腺、胸部和腹部皮肤在4种CT扫描方式下的吸收剂量分别为0.040～64.818 mGy、0.154～10.155 mGy、0.028～0.154 mGy、0.443～17.141 mGy和0.093～14.346 mGy。胸部扫描时空间辐射场的空气比释动能最大值为0.049 mGy,且与CT球管距离越大数值越小。结论 4种CT扫描方式对受检者常见组织的吸收剂量一般不会超过阈剂量。单次CT胸部扫描时陪检者所受剂量较小。为减少辐射危害,在CT扫描中可采取屏蔽措施来减少受检者组织吸收剂量,同时陪检者应适当增加与球管和诊断床的距离。     

131I的电离辐射对甲状腺功能早期影响的研究

目的探讨131I的电离辐射与甲状腺组织功能早期改变的关系,如血清TNF、IL-1β、IL-6、IL-8等细胞因子水平变化以及甲状腺组织本身的病理改变等.方法选用兔作动物实验(15只),分别在0、6、24、48、72h及1周时抽血做IL-1β、IL-8测定,并每次随机处死1～2只兔以做病理切片观察,1周时同时做甲功测定(TT3、TT4、FT3、FT4)并与0h比较.17例病情中及重度甲亢患者用治疗剂量的131I治疗(每人次用量146.2～469.9MBq,平均267.5MBq),治疗前和治疗后4～7天抽血做TNF、IL-1β、IL-6和IL-8测定.结果①使用131I6h后即可见兔血清IL-1β增高(P<0.05),IL-8于48h达高峰(P<0.01),两种细胞因子于1周时皆降低到0h水平(P>0.05).1周内兔血清甲状腺激素水平无明显变化(P>0.05).②甲亢患者131I治疗前后血清细胞因子的变化与兔有所不同,TNF无明显变化(P>0.05),IL-6和IL-8升高(P<0.05),而IL-1β反而降低,且差异显著(P<0.05).③摄取131I后兔甲状腺组织在不同时间内呈现不同的病理改变.结论①甲状腺组织摄取一定剂量的131I在不同时间内呈现不同的病理改变,但短期内甲状腺激素水平无明显变化.②某些细胞因子IL-1β、IL-6、IL-8等似可用作观察甲状腺组织对131I辐射效应反应的指标,但其临床价值有待于进一步探讨.     

不同照射剂量及照后培养不同时间小鼠骨髓基质细胞损伤的变化

目的 :研究γ射线照射剂量及照射后培养时间对体外培养的骨髓基质细胞 (BMSC)损伤的影响。方法 :体外培养的BMSC随机分为正常组和不同剂量照射组 ,利用流式细胞仪 (FCM)、HE染色等技术观察处理后BMSC凋亡率和坏死率的变化。结果 :照射剂量从 0增至 5 0Gy时 ,凋亡率和坏死率随照后培养时间的延长其增加的幅度较小 ,当照射剂量从 5 0Gy增至 70Gy时 ,其增加幅度较大 ;当剂量大于 70Gy时 ,BMSC的损伤主要表现为坏死率的相对增高。结论 :BMSC的凋亡和坏死与照射剂量和照后培养时间有关 ,且表现出一定的规律性     

真空紫外辐照对加成型硅橡胶光学性能的影响

考察了加成型硅橡胶在真空环境中经1000ESH紫外辐照后的性能变化。结果表明,辐照后材料均出现发黄的现象,光学透过率大幅度 下降,同时加入硅酸钾包覆后制备的热控涂层反射率下降。经原位测试与离位测试,发现加成型硅橡胶在两种不同条件下测得的结果差异较小,而在有机硅橡胶中加入ZnO后原位与离位测试结果则差异明显,表现出明显的漂白作用。