Possible ameliorative effect of aqueous extract of date (Phoenix dactylifera) pits in rats exposed to gamma radiation

Purpose: To evaluate the radioprotective efficacy of date (Phoenix dactylifera) pits extract (DPE) against γ-irradiation-induced liver damage in the male albino rats. For this study, 30-day survival, dose reduction factor (DRF), antioxidant status and some biochemical changes in the serum and hepatic tissue were evaluated.

Materials and methods: To calculate 30-day survival, median lethal dose of 30 days (LD50/30) and DRF, DPE was orally administered to rats for 21 days before irradiation with different doses (5, 6, 8, 10 and 12?Gy) of γ-rays and the rats were observed for 30 days post-irradiation. To evaluate the radioprotective efficacy of DPE against γ-irradiation induced-liver tissue damage, animals were divided into four groups (eight animals in each group). (i) Control: rats not subjected to any treatment; (ii) DPE: DPE was orally administrated (1000?mg/kg body weight) for 21 days; (iii) RAD: rats’ whole body exposed to 5?Gy of γ-rays; (iv) DPE?+?RAD: rats received DPE treatment for 21 days before γ-irradiation. Animals were sacrificed on the seventh day postexposure to radiation.

Results: The results showed that pretreatment prior to irradiation with DPE resulted in a significantly higher 30-day survival rate of rats after exposure to different doses of γ-irradiation. Furthermore, DPE treatment resulted in a significant improvement in the hepatic redox state, manifested by a marked increase of superoxide dismutase (SOD) and catalase (CAT) activities and glutathione content associated with a significant decrease of malondialdehyde (MDA) level. In addition, DPE exhibited hepatoprotective effect evidenced by a marked increase in serum levels of insulin, testosterone, high-density lipoprotein-cholesterol (HDL-c) and hepatic glucose 6 phosphate dehydrogenase (G6PHD) activity associated with a significant decrease in serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), γ-glutamyl transferase (γ-GT), glucose, total cholesterol (TC), triglycerides (TG), low density-lipoprotein cholesterol (LDL-c) and hepatic glucose 6 phosphatase (G6Pase) activity, compared with irradiated group. Moreover, DPE showed positive modulation in the levels of hepatic metals [(iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn)].

Conclusions: DPE treatment prior to gamma irradiation produced biochemical changes that could lead to a reduction in radiation-induced oxidative stress. Hence, we suggest that DPE may be useful as a new natural radioprotective agent.     

Synergistic effect of Ebselen and gamma radiation on breast cancer cells

Purpose: To explore the synergistic effect of a seleno-organic compound Ebselen (Ebs) and/or γ-radiation to exert antitumor effects on human breast cancer (MCF-7) cell line in vitro.

Materials and methods: Ebs cytotoxicity at various concentrations (10, 25, 50 and 75 μg), cell proliferation and clonogenic assay of Ebs and/or γ-radiation (at 1, 3 and 6?Gy), expression of p-IκBα and NF-κB, inflammatory cytokines levels (TNF-α, IL-2, INF-γ, IL-10 and TGF-β), apoptotic factors (Caspase-3, Granzyme-B and TRAIL) and angiogenic factor (VEGF) were investigated.

Results: The results showed that the effective dosage of this combination was observed at 25 μg/ml of Ebs with γ-radiation at 6?Gy. Data displayed a significant reduction in NF-κB mRNA along with an elevation in granzyme-B mRNA and TRAIL mRNA expression. Furthermore, protein expression of caspase-3 was elevated, whereas p-IκBα and p-NF-κB(p65) protein expression was reduced significantly. Also, a significant decline in TNF-α, IL-2, INF-γ, TGF-β with a significant increase in IL-10 levels were revealed. Meanwhile, a significant decrease in VEGF level and proliferation capacity were observed.

Conclusions: We conclude that a combination of Ebs with radiotherapy has a major antitumor efficiency in inducing apoptosis and inhibiting cancer cell progression, due to the synergistic effect in regulating gene and protein expression, and in a modulating response of pro-and anti-inflammatory cytokines.     

Determination of dead-layer variation in HPGe detectors

The dead-layer uniformity of the top surface of two high purity germanium detectors has been studied using a novel automated scanning set-up that allows a fine-grained topography of a detector's top and lateral surfaces. Comparisons between measurements and Monte Carlo simulations allowed implementation of a dead-layer variation into the detector model, which reproduces the measurements results. The effect of the non-uniform dead-layer on activity determinations based on low-energy γ-rays (i.e. below ~100 keV) has been determined to be of the order of 10% or more.     

Effects of gamma rays on the regeneration of murine hair follicles in the natural hair cycle

Purpose: This review evaluates the effects of γ-rays on the regeneration of murine hair follicles in the natural hair cycle. A series of studies were performed to investigate this issue, in which the whole bodies of C57BL/10JHir mice in the 1st telogen phase of the hair cycle were irradiated with γ-rays.

Results: The dermis of the irradiated skin showed a decrease in hair follicle density and induction of curved hair follicles along with the presence of white hairs and hypopigmented hair bulbs in the 2nd and 3rd anagen phases. An increased frequency of hypopigmented hair bulbs was still observed in the later hair cycle at postnatal day 200. There was no significant difference in the number of stem cells in the hair bulge region between control and irradiated skin.

Conclusions: These results show that the effects of γ-rays on the pigmentation of murine hair follicles are persistently carried over to later hair cycles, although those on the number and structure of hair follicles appear to be hidden by the effects of aging. Our findings may be important for understanding the mechanisms of the actions of stem cells on hair regeneration in connection with age-related phenotypes.     

Responses of the bacterial community to chronic gamma radiation in a rice paddy ecosystem

Purpose:?Public concern about radiation protection of the environment and non-human species is increasing. The potential impact of chronic gamma radiation on the bacterial community in a rice paddy ecosystem was investigated.

Materials and methods:?Paddy field microcosm samples were continuously exposed at a dose rate of 1 Gy day^?1 for five days after which the bacterial community structures in them were compared with those of unirradiated control samples by denaturing gradient gel electrophoresis (DGGE) of the 16S ribosomal ribonucleic acid (rRNA) gene. Dissolved ions in ponding waters of the microcosm samples were determined by ion chromatography.

Results:?The DGGE band profiles were clearly different between the control and exposure samples. Sequencing of selected DGGE bands revealed that a specific species of the genus Clostridium and of the genus Massilia were grown under radiation exposure. Additionally, the concentrations of sulphate ion in the ponding water of the microcosm samples increased under radiation exposure. Concentrations of Na⁺, Ca²⁺, and F^? inversely decreased.

Conclusions:?The data presented suggest that chronic gamma radiation affects the bacterial community structure and material cycles in the rice paddy ecosystem.     

Restorative role of persimmon leaf (Diospyros kaki) to gamma irradiation-induced oxidative stress and tissue injury in rats

Purpose: To evaluate the efficacy of persimmon leaf extract (PL (as a rich plant source) in modulation of radiation-induced liver injury and some metabolic variations in gamma-irradiated rats.

Materials and methods: PL at a dose of 1000?mg/kg body weight (P₁₀₀₀) was administered to male albino rats via gastric intubation for 15 days after whole body γ-irradiation (6?Gy).

Results: Irradiated rats showed significant decreases in hepatic glutathione content (GSH), superoxide dismutase (SOD), catalase (CAT) and xanthine dehydrogenase (XDH) activities with significant increases in malondialdehyde (MDA) level and xanthine oxidase (XO) activity designating oxidative stress. In parallel significant increases in serum aspartate and alanine transaminase (AST, ALT), alkaline phosphatase (ALP), γ-glutamyl-transferase (GGT) activities and bilirubin content were recorded indicating liver injury. In addition, hyperglycemia, hypoinsulinemia and dyslipidemia (elevated total cholesterol, triglycerides, low density lipoprotein-cholesterol and Atherogenic Index and decreased high density lipoprotein-cholesterol) were recorded. PL treatment has significantly attenuated radiation-induced oxidative stress in hepatic tissues concomitant with significant amelioration of liver function and metabolic disturbances.

Conclusion: It is concluded that PL may have therapeutic potential to alleviate the severity of radiation-induced liver injury, hyperglycemia, hypoinsulinemia and dyslipidemia.     

Responses of the bacterial community to chronic gamma radiation in a rice paddy ecosystem

Purpose: Public concern about radiation protection of the environment and non-human species is increasing. The potential impact of chronic gamma radiation on the bacterial community in a rice paddy ecosystem was investigated. Materials and methods: Paddy field microcosm samples were continuously exposed at a dose rate of 1 Gy day(-1) for five days after which the bacterial community structures in them were compared with those of unirradiated control samples by denaturing gradient gel electrophoresis (DGGE) of the 16S ribosomal ribonucleic acid (rRNA) gene. Dissolved ions in ponding waters of the microcosm samples were determined by ion chromatography. Results: The DGGE band profiles were clearly different between the control and exposure samples. Sequencing of selected DGGE bands revealed that a specific species of the genus Clostridium and of the genus Massilia were grown under radiation exposure. Additionally, the concentrations of sulphate ion in the ponding water of the microcosm samples increased under radiation exposure. Concentrations of Na(+), Ca(2+), and F(-) inversely decreased. Conclusions: The data presented suggest that chronic gamma radiation affects the bacterial community structure and material cycles in the rice paddy ecosystem.     

Effects of gamma radiation on maize samples contaminated with Fusarium verticillioides.

The efficacy of gamma-irradiation as a method of decontamination of maize containing Fusarium verticillioides under controlled conditions of relative humidity (RH) (97.5%) and water activity has been studied. Maize grains inoculated with a spore suspension of F. verticillioides were irradiated to 2, 5, and 10 kGy. Thereafter, the irradiated and control samples were analyzed for the presence of fumonisins, their viable cells were counted, and their morphology was investigated by electronic microscopy. It was found possible to decrease the risk of exposure to fumonisins by irradiating maize to 5 or 10 kGy. However, at the dose of 2 kGy, the survived fungi (36%) can produce more fumonisins than the fungi in the control unirradiated samples under the same conditions.     

富勒烯衍生物C3对AHH-1细胞电离辐射的防护效应

目的 研究富勒烯衍生物C3(以下简称C3)对AHH-1细胞电离辐射的防护效应,探讨该类化合物作为新型辐射防护剂的发展前景.方法 通过化学合成制备C3,用台盼兰拒染试验检测C3对AHH-1细胞的毒性作用.在此基础上于AHH-1细胞培养体系中加入不同浓度C3,以不同剂量60Coγ射线照射细胞,通过台盼兰拒染试验检测C3化合物对细胞的毒性作用,用Annexin-V/PI染色、Facscalibur流式细胞术等,分析C3化合物对γ射线照射细胞增殖活力和细胞凋亡的变化.结果 在细胞培养体系中,终浓度范围0～400 mg/L的C3对培养的对数生长期AHH-1细胞活力几乎无影响,AHH-1细胞台盼兰拒染率无明显变化(P＞0.05).C3对1～8 Gy γ射线照射的AHH-1细胞具有良好的辐射防护效应,终浓度在10 mg/L时即显示其对4 Gy60Co γ照射的细胞有保护效应,且随浓度增加而增加;终浓度达200～400 mg/L时,照射细胞存活率已接近未照射的正常细胞(P＞0.05),辐射诱导的细胞调亡率和细胞死亡率用药组均显著低于未用药的对照组(P＜0.01).研究结果还显示,C3提高照射细胞存活率的作用还与给药时间有关,照前24 h至照前即刻给药最为有效.结论 C3对不同剂量60Co γ射线照射的AHH-1细胞具有较好的电离辐射防护作用,该防护效应与用药浓度有关,C3浓度越高,防护作用越好;且在本实验产生辐射防护作用的浓度范围内,C3对培养的对数生长期AHH-1细胞存活率几乎无影响,提示该类化合物有作为新型辐射防护剂的研究前景.     

医学重要真菌的实验室诊断进展之一--实验室常规方法的改进和发展

如何快速、准确地诊断机会性真菌感染，特别是深部真菌感染一直是临床微生物实验室面临的难题之一。由于传统的真菌培养耗时长，敏感性低，血清学方法特异性和敏感性差，这就要求研究者改进和发展传统技术进行诊断，指导临床选择合适的抗真菌药物，及早治疗侵袭性真菌病。本文根据近年来的文献报道，对以念珠菌为主的实验室常规诊断方法的改进和发展作一概述。     

软X线照射对体外培养大鼠成纤维细胞增殖的影响

目的观察软X射线照射对体外培养的成纤维细胞增殖的影响.方法观察培养的大鼠皮肤成纤维细胞照射后细胞计数的变化、划痕实验和"营救"实验.结果在0.5Gy～8Gy剂量范围内,剂量与成纤维细胞的增长成反比,而且0.5～4Gy剂量的量效关系经回归分析成直线型.0.5Gy、1Gy剂量照射后,在1～3天的增长的幅度明显比3～5天的小,而2Gy曲线在1～5天增长幅度明显低于5～7天.在0.1～0.025Gy的照射范围内成纤维细胞的增殖曲线和空白对照没有差别.划痕实验中对照的长满时间明显比照射的长满时间短,实施了"营救"措施的细胞照射与对照的长满时间没有明显差别.结论照射后成纤维细胞的增长与剂量成依赖关系,并且剂量越大细胞增殖恢复也越慢.照射对细胞的运动也有抑制作用.未照射细胞对照射成纤维细胞的增长有"营救"作用.     

Effect of gamma radiation on the metamorphic stages of Dermestes maculatus DeGeer (coleoptera: dermestidae)

The effects of γ-radiation on all stages of the hide beetle Dermestes maculatus, DeGeer were studied. Eggs of D. maculatus were more susceptible to γ radiation than other stages. Egg radiosensitivity decreased with increasing embryonic development. An absorbed dose of 200 Gy killed the 1st, 6th and 7th instar larvae, but the 4th and 5th instar larvae were more resistant. The developmental period increased in treated larvae. Pupae (24 h) treated with 150 Gy failed to eclose, but eclosion was not affected in older pupae. Adults from female pupae irradiated at 72 h with 150 Gy were infertile, but male pupae required more than 200 Gy for sterilization. The average number of eggs per female decreased with increasing doses when either the male or female of the pair was irradiated as puape or adults. Adult males were sterile after irradiation 300 Gy and adult females treated with the same dose failed to lay eggs. Newly emerged irradiated adults or female adults from irradiated 72-h-old pupae recovered some fertility after treatment with doses as high as 150 Gy. Adult males from irradiated 72-h-old pupae were treated at doses of 50 and 100 Gy showed a higher reproductive capacity at 60 days than at 15 days post-treatment. A dose between 200 and 300 Gy was necessary to provide complete sterility of 24-h-old adults.     

维生素 E对果蝇辐射氧化损伤机制的影响

目的 探索不同浓度维生素E对γ射线照射后果蝇幼虫敏感性的影响。 方法 使用不同浓度（100、500、1000、1500 mg/L）维生素E处理W1118果蝇幼虫,137Cs γ射线 50 Gy 进行照射,测定果蝇幼虫的蛹化率和羽化率、羽化后48 h死亡率、过氧化氢酶（CAT）活性和谷胱甘肽（GSH）含量,分析其抗氧化能力和氧化损伤状态。组间的比较采用LSD-t检验。 结果 1000、1500 mg/L维生素E组果蝇幼虫的蛹化率、羽化率、攀爬能力、CAT活性、GSH含量均明显比单纯照射对照组高,且差异均有统计学意义（t=2.864~16.462,均P<0.05）。与未照射对照组比较,1000 mg/L和1500 mg/L维生素E组的果蝇幼虫羽化为成虫48 h内的死亡率分别从（54.0±5.0）%降低至（36.1±7.6）%和（37.5±5.8）%,差异均有统计学意义（t=3.386,P=0.028;t=3.718,P=0.021）。 结论 维生素E通过减少氧化性应激来减缓果蝇幼虫辐照后的氧化损伤,并能提高果蝇的辐射抗性。     

Relationship between radioadaptive response and individual radiosensitivity to low doses of gamma radiation: an extended study of chromosome damage in blood lymphocytes of three donors

Purpose: Our study aimed at evaluating: 1) whether well-established variability in radioadaptive response (AR) in various donor blood lymphocytes might be attributed to inter-individual differences in radiosensitivity to different low dose levels; 2) whether AR is reproducibly present over time in the lymphocytes of AR-positive individuals.

Experimental procedure: Whole blood samples of three donors were exposed to low doses (2–30 cGy) of γ-radiation alone (G₀ phase) or followed by a 1?Gy challenge dose (late S/early G₂ phase), and chromosome aberration were scored to assess the dose-response relationship and adaptive response, correspondingly. Three experiments were performed on blood samples of the same donors at six month intervals.

Results: Significant differences in dose response relationship for blood lymphocytes were found among individuals. In most cases, the donors exhibited initial low-dose hypersensitivity (HRS) followed by an increase in radioresistance (IRR). AR could be successfully induced by some particular priming doses in the lymphocytes of each donor; however, the doses resulting in a protective response were quite different for all three donors. These protective doses could equally belong to either HRS or IRR region on the individual dose-response curves. In most cases, no clear AR outcome dependence on the priming dose was found at all. Moreover, pre-exposure to the same low dose could result in opposite effects in the lymphocytes of the same donor in different experiments.

Conclusions: AR variability in human lymphocytes is not attributed to variation in radiosensitivity among individuals and is more drastic than was believed. It seems doubtful that AR is a universal phenomenon which has a consistent impact on the effects of radiation exposure on humans.