婴幼儿防辐射拍片床在X射线辐射防护中的应用

目的:观察婴幼儿防辐射拍片床对X射线辐射的防护效果.方法:新生儿由于病情危重,常需要进行床边X射线摄影,我科自行设计(已获国家专利、专利号201020562412.1)并应用婴幼儿防辐射拍片床进行床边X射线辐射防护.结果:应用婴幼儿防辐射拍片床对X射线辐射防护的效果较以前采用单块铅屏风好,差异有统计学意义(P＜0.05).结论:婴幼儿防辐射拍片床具有辐射防护效果好、设计合理、结构简单、安全可靠、使用方便、易于维护的特点,可广泛适用于婴幼儿重症监护室或其他特殊领域.     

Melanin, a promising radioprotector: Mechanisms of actions in a mice model

The radioprotective effect of extracellular melanin, a naturally occurring pigment, isolated from the fungus Gliocephalotrichum simplex was examined in BALB/C mice, and the probable mechanism of action was established. At an effective dose of 50 mg/kg body weight, melanin exhibited both prophylactic and mitigative activities, increasing the 30-day survival of mice by 100% and 60%, respectively, after exposure to radiation (7 Gy, whole body irradiation (WBI)). The protective activity of melanin was primarily due to inhibition of radiation-induced hematopoietic damages as evidenced by improvement in spleen parameters such as index, total cellularity, endogenous colony forming units, and maintenance of circulatory white blood cells and platelet counts. Melanin also reversed the radiation-induced decrease in ERK phosphorylation in splenic tissue, which may be the key feature in its radioprotective action. Additionally, our results indicated that the sustained activation of AKT, JNK and P38 proteins in splenic tissue of melanin pre-treated group may also play a secondary role. This was also supported by the fact that melanin could prevent apoptosis in splenic tissue by decreasing BAX/Bcl-XL ratio, and increasing the expressions of the proliferation markers (PCNA and Cyclin D1), compared to the radiation control group. Melanin also reduced the oxidative stress in hepatic tissue and abrogated immune imbalance by reducing the production of pro-inflammatory cytokines (IL6 and TNFα). In conclusion, our results confirmed that fungal melanin is a very effective radioprotector against WBI and the probable mechanisms of radioprotection are due to modulation in pro-survival (ERK) signaling, prevention of oxidative stress and immunomodulation.     

Gene therapy and cell therapy for the management of radiation damages to healthy tissues: Rationale and early results

Nowadays, ionizing radiations have numerous applications, especially in medicine for diagnosis and therapy. Pharmacological radioprotection aims at increasing detoxification of free radicals. Radiomitigation aims at improving survival and proliferation of damaged cells. Both strategies are essential research area, as non-contained radiation can lead to harmful effects. Some advances allowing the comprehension of normal tissue injury mechanisms, and the discovery of related predictive biomarkers, have led to developing several highly promising radioprotector or radiomitigator drugs. Next to these drugs, a growing interest does exist for biotherapy in this field, including gene therapy and cell therapy through mesenchymal stem cells. In this review article, we provide an overview of the management of radiation damages to healthy tissues via gene or cell therapy in the context of radiotherapy. The early management aims at preventing the occurrence of these damages before exposure or just after exposure. The late management offers promises in the reversion of constituted late damages following irradiation.     

CGEONA对荷LA-795肺腺癌小鼠和正常小鼠放射敏感性的影响

目的 为了寻低低毒有效的放射增敏剂,观察ＣＧＥＯＮＡ（羟基－苯乙烯基锗倍半氧化物钠盐）对荷瘤小鼠和正常小鼠放射敏感性的影响。方法 放射增敏实验用Ｔ－７３９小鼠,肿瘤模型ＬＡ－７９５肺腺癌,采用肿瘤再生长延缓法评价效果;放射防护实验用昆明种小鼠,观察３０ｄ存活率和对造务系统的影响。     

Alternative imaging strategy of solitary pulmonary nodule by FDG PET/CT: Can be imagined a tailored PET?

ObjectivePatients with solitary pulmonary nodule (SPN) are usually sent to total-body positron emission tomography/computed tomography (PET/CT) examination with 18F-fluorodeoxyglucose (FDG). However, a segmental scan strategy may improve cost/effectiveness in this category of patients.ConclusionA segmental PET/CT scan only at the chest level could be performed in patients with indeterminate SPN. Limiting the PET/CT field to the thoracic region would greatly affect on radiobiology, department organization and health-care costs.     

Tumor sensitization and protection: influence of stromal injury on estimates of dose modification

Tumor regrowth delay is an assay which reflects tumor cell kill but can be modified by growth rate changes resulting from damage to the stroma (tumor bed effects). If the stromal damage is modified by radiosensitizers and radioprotectors to a different degree from the tumor cells, the overall measurement of dose modifying factors may be influenced by the choice of a regrowth size for the growth delay analysis. We have studied the response of two mouse tumors; a fibrosarcoma which showed only a small TBE and a carcinoma which showed a very large TBE. Sensitizer enhancement ratios and protection factors have been obtained by assessing regrowth to a variety of endpoint sizes. The dose modifying effects on the stroma have then been determined by analyzing the regrowth rates of tumors after irradiation. The choice of endpoint size modified both the sensitizer enhancement ratio and the protection factor for both tumors. It appears that stromal damage may be the cause of the radioprotection observed in the carcinoma, whereas direct tumor cell radioprotection is indicated in the fibrosarcoma. Both direct tumor cell killing and cell death secondary to stromal damage will play an important role in determining the local control of irradiated tumors.     

γ线对小鼠细胞遗传学的影响及重组人超氧化物歧化酶的抗放射作用(论著)

目的：研究γ射线对小鼠遗传学的影响及重组人超氧化物歧化酶（rhSOD）的抗放作用。方法：实验用甲基纤维素缩集法计算淋巴细胞微核率和活体秋水仙素法进行骨髓细胞染色体畸变率分析。结果：（1）4．0Gyγ线能明显增加小鼠淋巴细胞微核细胞率、微核率和骨髓染色体畸变率。（2）rhSOD可减轻射线所致小鼠淋巴细胞微核细胞率、微核率及骨髓细胞染色体畸变率，尤以照射前后给药为佳。结论：rhSOD对小鼠细胞遗传学辐射损伤有明显保护作用。     

重组人铜锌超氧化物歧化酶对小鼠骨髓造血粒─巨系祖细胞的辐射防护作用

目的：探讨重组人铜锌超氧化物歧化酶（ｒｈＣｕＺｎＳＯＤ）的辐射防护作用及其机理。方法：通过γ线辐射损伤小鼠的体内和体外实验，观察了ｒｈＣｕＺｎＳＯＤ和聚乙二醇修饰的ｒｈＣｕＺｎＳＯＤ（ＰＥＧ－ｒｈＣｕＺｎＳＯＤ）对小鼠骨髓造血粒－巨系祖细胞克隆产生率（ＣＦＵ－ＧＭ）的影响。结果：体内实验，小鼠整体照射，静脉给药，以上两种酶（２５`０～３００ｍｇ／ｋｇ）均能非常显著地提高ＣＦＵ－ＧＭ的数量。其中以照射前后联合给药效果最好。而单纯照射前给药，ｒｈＣｕＺｎＳＯＤ仅在照前１小时给药效果较好；ＰＥＧ－ｒｈＣｕＺｎＳＯＤ则在照前３小时或照前１小时给药都有较好的效果。体外实验，小鼠离体细胞照射并给药，未见ｒｈＣｕＺｎ－ＳＯＤ对ＣＦＵ－ＧＭ的影响。结论：以上两种酶对小鼠骨髓ＣＦＵ－ＧＭ有良好的辐射防护作用，其机理可能是通过机体防御系统作用的间接途径实现的。ＰＥＧ－ｒｈＣｕＺｎＳＯＤ的生物半衰期较长，可增加给药时机，因而具有更大的实用价值。     

In vivo radioprotective effect of AcSDKP on canine myelopoiesis

 The tetrapeptide acetyl-N–Ser-Asp-Lys-Pro (AcSDKP) interferes with G₁/S-phase progression, and the resulting cell cycle arrest is thought to protect hematopoietic stem cells against injury by cycle-active cytotoxic agents. We investigated the radioprotective effect of AcSDKP in a canine radiation model. Dogs were given total-body irradiation (TBI) at an exposure rate of 10 cGy/min, either without further therapy (control) or with administration of AcSDKP at 0.05–500 μg/kg/24 h beginning before and continuing until after completion of TBI. At 400 cGy of TBI, one of 28 control dogs and one of eight AcSDKP-treated dogs recovered hematopoiesis (p=0.40). At 300 cGy, seven of 21 control dogs recovered hematopoiesis compared with five of five AcSDKP-treated dogs (p=0.01). In dogs given 300 cGy and AcSDKP, the granulocyte nadirs were less profound (p=0.04) and occurred later (p=0.04) than among controls; platelet kinetics did not differ. These data suggest, therefore, that AcSDKP provides a radioprotective effect in dogs exposed to 300 cGy TBI. Such an effect might be beneficial in recipients of intensive radiation therapy. Conceivably, the effect on hematopoietic recovery could be amplified by growth factor administration after irradiation. Received: 9 October 1996 / Accepted: 18 December 1996     

Acidic polysaccharide of Panax ginseng as a defense against small intestinal damage by whole-body gamma irradiation of mice

An acidic polysaccharide of Panax ginseng (APG), ginsan, has been reported to protect the hematopoietic system by increasing the number of bone marrow cells and spleen cells. Therefore, we evaluated the ability of APG to protect mice from radiation-induced damage of the small intestine. APG treatment caused the lengthening of villi and a numerical increase of crypt cells in the small intestine at 3.5 days after 7 Gy irradiation compared to irradiated, non-treated controls. In addition, APG significantly inhibited irradiation-induced apoptosis by decreasing the amount of pro-apoptotic p53 and Bax as well as augmenting that of anti-apoptotic Bcl-2 at 24 h after irradiation. These results indicate that APG might be a useful adjunct to therapeutic irradiation as a protective agent for the gastrointestinal tract of cancer patients.