Upregulation of VEGF and FGF2 in normal rat brain after experimental intraoperative radiation therapy

The expression of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF)2 in the irradiated brain was examined to test how a single high dose radiation, similar to that used for intraoperative radiation therapy given to the normal cerebrum, can affect the vascular endothelium. After a burr hole trephination in the rat skull, the cerebral hemisphere was exposed to a single 10 Gy dose of gamma rays, and the radiation effect was assessed at 1, 2, 4, 6, and 8 weeks after irradiation. Histological changes, such as reactive gliosis, inflammation, vascular proliferation and necrosis, were correlated with the duration after irradiation. Significant VEGF and FGF2 expression in the 2- and 8-week were detected by enzyme-linked immunosorbent assay quantification in the radiation group. Immunohistochemical study for VEGF was done and the number of positive cells gradually increased over time, compared with the sham operation group. In conclusion, the radiation injuries consisted of radiation necrosis associated with the expression of VEGF and FGF2. These findings indicate that VEGF and FGF2 may play a role in the radiation injuries after intraoperative single high-dose irradiation.     

近场射频辐射条件下大白鼠共振吸收频率的研究

在Ｅ极化、辐射电平１ｍｗ／ｃｍ２条件下，在４０．６８ＭＨｚ～４ＧＨｚ频段内６个频率点上，利用红外热图术观察了６０只Ｗｉｓｔａｒ成年大白鼠，连续辐射１ｈ后，体表及各部位体表温度变化。结果表明，体表温度与肛温变化有很好的一致性，并在１．５ＧＨｚ有最大值。它表明在该频率下，实验鼠吸收射频能量最大，表现出明显的谐振吸引特性。     

Radioprotective efficacy and acute toxicity of 5-androstenediol after subcutaneous or oral administration in mice

We previously showed that one subcutaneous (sc) injection of 5-androstene-3beta,17beta-diol (AED) stimulated the innate immune system in mice and prevented mortality due to hemopoietic suppression after whole-body ionizing irradiation with gamma rays. In the present study, we tested whether there was any significant toxicity in mice that might hinder development of this steroid for human use. There were no indications of toxicity in chemical analyses of serum after sc doses as high as 4000 mg/kg. At this dose, 2 of 54 mice died when given AED alone. When 4800 mg/kg was given orally, no deaths resulted. The only adverse findings attributed to AED administration were 1) a moderate elevation of granulocytes in abdominal organs and fat after sc injections of 320 mg/kg; and 2) occasional wasting of skin over the injection site in female B6D2F1 but not male C3H/HeN mice. Significant weight loss (6%) was observed after sc injections of 320 mg/kg but not 160 or 80 mg/kg. When male C3H/HeN mice were injected sc with AED at doses of 0-200 mg/kg 24 h before whole body gamma-irradiation (9 Gy), a significant improvement in survival was observed at doses as low as 5 mg/kg. Oral administration of AED produced significant survival enhancement at a dose of 1600 mg/kg. We conclude that the radioprotective efficacy of AED is accompanied by low toxicity.Androst-5-ene-3 beta, 17 beta-diol; Ionizing radiation; Experimental radiation injuries; Toxicity; Clinical chemistry; Histopathology     

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.     

The influence of radiation therapy on T-lymphocyte subpopulations defined by monoclonal antibodies

We studied the influence of radiation therapy on lymphocyte subpopulations in 17 patients undergoing adjuvant radiation therapy for primary breast cancer, and eight patients receiving brachytherapy and external beam irradiation for primary cancer of the uterus. Radiation therapy reduced B- and T-lymphocytes in proportion to the total lymphocyte population so that their percentages remained unchanged. Determination of helper and suppressor T-lymphocytes before, during and 6 months after completion of radiotherapy revealed that in both groups of patients suppressor T-lymphocytes were more resistant to and recovered faster after radiotherapy. This resulted in a decline of the "immunoregulatory balance" (helper/suppressor ratio). Although this ratio had been higher in both groups of patients than in healthy age- and sex-matched controls before therapy, it became normal and subnormal during and after radiotherapy. The clinical significance of the differential influence of radiotherapy on T-lymphocyte subpopulations remains to be determined.     

The effect of lucanthone on sublethal radiation damage, in vivo

The capacity of the Chinese hamster jejunal crypt cell to accumulate and repair sublethal radiation damage was determined by analyzing the return of the shoulder of the radiation dose-crypt microcolony survival curve (Dr) after a priming dose of 1250 rad. The control split dose crypt cell survival curve exhibited a D0, Dr and "n" of 179 +/- 3 rad, 261 +/- 3 rad and 4.3 respectively; repair of sublethal radiation damage was completed by two hours post-irradiation. The effect of lucanthone (an antischistosomal DNA intercalating agent) on the crypt cell's capacity to accumulate and repair sublethal radiation damage was determined by injecting the drug (100 mg/kg, i.p.) at intervals before irradiation with a priming dose of 1250 rad, followed two hours later by graded doses. Injection coincident with the priming dose of radiation resulted in a 22 rad reduction of the Dr (compared to control Dr). Injection eight hours before the priming dose almost completely inhibited the accumulation and repair of sublethal radiation damage so that the resultant Dr two hours later was only 29 rad (a 232 rad reduction). At no time was the D0 of the crypt cell survival curve affected by lucanthone. These data confirm previous results from whole crypt analysis and LD50/7 analysis that non-toxic concentrations of lucanthone reversibly inhibit the accumulation and repair of sublethal radiation damage in a time-dependent manner with complete inhibition approximately eight hours post-injection. This drug is useful for the study of sublethal radiation damage in vivo and may be beneficial in radiation therapy of cancer when it is desirable to inhibit the repair of sublethal radiation damage.     

热释光剂量计在核电厂环境监测中的应用

目的 研究岭澳核电站运营后大亚湾核电基地6台机组气态流出物排放对周围陆地环境辐射水平的影响。方法 利用热释光剂量计（TLD）监测广东大亚湾核电基地外围环境辐射水平,在大亚湾核电周围陆地环境布设25个TLD监测点,每3个月左右回收热释光剂量计并测量,长期观测核电周围环境辐射水平变化。结果 2011—2020年大亚湾核电基地外围环境用热释光剂量计测量得到的γ辐射剂量率年均值范围为76.7～207.1 nGy/h、均值为（123.3 ± 5.7） nGy/h,年均值变化相对偏差范围为2%～12%,TLD监测结果、剂量率瞬时测量结果与20世纪国家环保总局组织的调查结果、核电运营前的本底水平一致。结论 不同TLD监测点环境天然辐射水平差异较大,核电站周围50 km范围内的总体环境γ辐射水平没有变化,核电运行气态流出物的释放未对外围环境辐射水平产生累积影响。     

2014—2021年四川省从事放射性工作人员淋巴细胞微核率分析

目的 分析2014—2021年四川省放射性职业健康体检中从事放射性工作人员的外周血淋巴细胞微核率情况,为今后职业健康防护提供依据。方法 收集2014—2021年从事放射工作人员的健康体检资料为放射组,相应年份的非放射工作人群为对照组,对其外周血淋巴细胞微核率进行分析,并对异常增高者（＞4‰）的暴露工龄、工种及停止暴露年限采用t检验、u检验、方差检验及χ2检验等检验方法进行比较。结果 放射组与对照组外周血淋巴细胞微核率总体分布差异有统计学意义（u = 2.348,P = 0.019）,放射组2014—2019年外周血淋巴细胞微核率均值有缓慢下降趋势,2020—2021年有较明显增高（2020—2019年间k - w检验h = 3.961,P = 0.002）,而对照组呈波动性呈不规则变化;各年度放射组异常增高人数占比与对照组异常增高人数占比差异均有统计学意义（合计值χ2 = 51.425,P＜0.001）;而根据工种的不同,放射医学组与非放射医学组微核率差异有统计学意义（χ2 = 194.524,P＜0.001）,核医学组与放射治疗组微核率差异有统计学意义（χ2 = 47.778,P＜0.001）,介入治疗组与放射治疗组微核率差异有统计学意义（χ2 = 25.565,P＜0.001）;涉核部队暴露工龄接近,停止暴露年限小于10年和大于40年异常增高所占比例分别与另外4个区间之和差异有统计学意义（χ2 = 17.146,P＜0.001;χ2 = 6.977,P = 0.008）。结论 四川省从放人员微核异常率近两年呈增高趋势,特别是介入治疗和核医学工作人员的占比明显,建议加强放射工作人员的健康防护。     

实时辐射数据对介入手术人员辐射暴露的影响

目的 了解医务人员辐射暴露情况,为介入手术医务人员,提供实时辐射剂量监测数据。方法 选择2019年9月—2022年3月在介入手术室参与心脏手术的医务人员96人次作为研究对象。按时间进展进行分组,干预组43人次,对照组53人次。干预组研究对象在手术过程中,提供实时剂量监测数据;对照组研究对象按常规流程进行手术。比较2组研究对象的平均术中辐射剂量率。结果 干预组研究对象的中位辐射剂量率为88.80 μSv/h,对照组研究对象的中位辐射剂量率为188.40 μSv/h。干预组较对照组研究对象,辐射剂量率明显降低,差异有统计学意义（U = 637.000,P = 0.000）。结论 为介入手术医务人员提供实时剂量监测数据,可有效降低医务人员职业辐射暴露,改善医务人员的职业辐射防护。     

电离辐射对心血管内科医务人员甲状腺功能的影响

目的 调查电离辐射对心血管内科医务人员甲状腺功能的可能影响。方法 以46例暴露于电离辐射的心血管内科医务人员为调查对象。收集调查对象人口学特征,采用化学发光法检测血清游离三碘甲状酪氨酸（free triiodothyronine,fT3）、游离四碘甲状酪氨酸（free thyroxine,fT4）、促甲状腺激素（thyroid-stimulating hormone,TSH）水平,采用热释光个人剂量计测定2019年辐射个人剂量当量[Hp（10）]及2015—2019年5年累计Hp（10）剂量。采用精准logistic回归模型评价甲状腺功能改变与年龄、性别、既往甲状腺疾病病史、甲状腺疾病家族史、工作岗位、工作年限、既往辐射暴露史等人口学特征的关联。结果 调查对象亚临床甲状腺功能减退症（血清TSH水平升高,但fT3和fT4水平无变化）发生率为6.5%。2019年,调查对象H_p（10）剂量为0～4.5 mSv,平均剂量（0.2 ±0.7） mSv,中位剂量0 mSv;2015—2019年5年累计H_p（10）剂量为0～11.6 mSv,平均剂量（0.8 ±2.3） mSv,中位剂量0 mSv。精准logistic回归分析显示,调查对象甲状腺功能异常与年龄、性别、甲状腺疾病家族史、既往甲状腺疾病病史、工作岗位、工作年限、既往辐射暴露史等人口学特征均无统计学关联（P均> 0.05）。结论 长期暴露于低剂量电离辐射可能增加心血管内科医务人员亚临床甲状腺功能减退症发生风险