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Background: All aerobically growing organisms suffer from exposure to oxidative stress, caused by partially reduced forms of molecular oxygen, known as reactive oxygen species (ROS). These are highly reactive and capable of damaging cellular constituents such as DNA, lipids and proteins. Consequently, cells from many different organisms have evolved mechanisms to protect their components against ROS. It is known to have some genes for resistance to heavy metals and ionizing radiation (IR). Materials and Methods: Saccharomyces cerevisiae is an ideal model organism for deducing biological processes in human cells. In this work, cell viability and gene expression was investigated in yeasts treated with IR, HgCl2, and IR combined with HgCl2. Cell viability was measured by colony forming unit (CFU) method in an YPD medium. Gene expression was analyzed by the Real-time PCR. Results: The viability was lower at the higher dose. At a dose above a certain level, the viability came down to zero. The combined treatment decreased the viability, as well. Metal resistance genes were expressed in the cells treated with HgCl2. In a similar way, irradiation also triggered the expression of some radiation resistance genes. YCF and YAP genes were induced consecutively with the HgCl2 concentration, and also with a higher total dose under a lower dose rate condition. These two genes were, however, expressed differently under the 0.2 mM HgCl2 treatment condition. In the cells treated with 0.1-0.2 mM HgCl2, the viability was higher than with any other concentrations. Conclusion: The results demonstrated that the higher dose induced more expression of oxidative stress resistance genes related to cell survival mechanism. Combined treatment of radiation with mercury chloride resulted in synergistic effects leading to a higher expression of the genes than treatment of a single stressor alone. Iran. J. Radiat. Res., 2009 6 (4): 161-166

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Background: Genistein is a soya isoflavone, which is found naturally in legumes, such as soybeans and chickpeas. Radiation–induced free radicals in turn impair the antioxidative defense mechanism, leading to an increased membrane lipid peroxidation that results in damage of the membrane bound enzyme and may lead to damage or death of cell. Hence, the lipid peroxidation is a good biomarker of damage occurs due to radiation and the inhibition of lipid peroxidation is suggestive of radioprotective action. Glutathione has been shown to protect cells against oxidative stress by reacting with peroxides and hydroperoxides and determines the inherent radiosensitivity of cells. Materials and Methods: For experimentation, healthy Swiss Albino male mice of 6 -8 weeks old were selected from inbred colony. Genistein was dissolved in dimethyl sulfoxide and then prepared different concentration solutions so that the volume administered intraperitoneally was 0.5 ml. Lipid peroxidation was estimated by the method of Ohkawa and GSH was estimated by the method of Moron. Results: The intraperitoneal administration of optimum dose (200 mg/kg body weight) of Genistein before 24 hrs and 15 minutes of irradiation (8 Gy at a dose rate of 1.02 Gy/min) reverted the increase in lipid peroxidation (by 18.01% ± 3.05) and decrease of Glutathione (by 62.05% ± 21.58) caused by irradiation in liver of Swiss albino mice. Statistically analyzed survival data produced a dose reduction factor (DRF) = 1.24. Conclusion: The results indicate that Genistein against radiation effect may pave way to the formulation of medicine in radiotherapy for normal tissue and possible against radiomimetic drug induced toxicity. Iran. J. Radiat. Res., 2009 7 (4): 187-199

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Background: Spindle trees (Euonymus japonica Thunb.) growing in an industrial complex area containing pollutants is chronically injured thus need to build up their resistance. Antioxidant enzymes and cell membrane stability have been widely used to differentiate stress tolerance. Materials and Methods: Leaves of spindle trees from a clean control area (Kijang) and an industrial area (Onsan) where is one of the heavily polluted areas in Korea were subsequently irradiated with 0, 50 and 100 Gy of gamma rays from a 60Co isotopic source, and evaluated for the level of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) and lipid peroxidation (LPO). Results: Air pollution-stressed plants showed better adaptation to ionizing radiation (IR) stress and are better protected from the oxidative damage, and rapidly up-regulate their antioxidative systems. The adaptive plants growing in the polluted area are less sensitive to consecutive oxidative stresses such as gamma rays, having a higher capacity of resistance to ionizing radiation, compared to the samples taken from the clean area. Conclusion: Air pollution-stressed plants showed lesser changes in the level of antioxidant enzymes after irradiation due to their enhanced antioxidant capacity. The enzymatic differences in plants irradiated with gamma rays can be used as biochemical end-points for environmental monitoring.

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Background:  The development of nanotechnology has been a boon to mankind as its significance paved the way for several applications in therapeutics. This study was to evaluate the anti-arthritic capability of nano Selenium-lovastatin mixture (Lov-Se) against inflammatory cascade in arthritic irradiated rats. Materials and Methods: Animal model of Arthritis was organized by subcutaneous injection of Complete Freund’s adjuvant; CFA. Rats were exposed to γ-radiation (2Gy every 3 days up to total dose of 8 Gy). Lov-Se (1ml ≈ 20 mg kg⁻¹ day⁻¹Lov and 0.1 mg kg⁻¹ day⁻¹Se) was administrated by daily oral injection. The antioxidant parameters (heart glutathione peroxides; GSH-Px, catalase; CAT, superoxide dismutase; SOD, xanthine dehydrogenase; XDH, reduced glutathione; GSH and blood selenium; Se), oxidant markers (heart Xanthine oxidase; XO, Nitric oxide; NO, protein carbonyls and thiobarbituric acid reactive substances; TBARS) and the inflammatory molecules (serum tumor necrosis factor-alpha TNF-α, C-reactive protein; CRP and rheumatoid factor; RF) were determined. Results: The arthritic and arthritic irradiated rats were displayed augment oxidative stress, inflammatory cascade and impaired antioxidant status compared to control. Conclusion: The data revealed that Lov-Se administration ameliorate oxidative, antioxidants parameters as well as inflammatory factors. The prolonged administration of Lov-Se mixture in appropriate concentration could exert a considerable systemic anti-inflammatory action through adjustment of red-ox tone and the integration of XDH/XO ratio.

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Background: Our purpose was to investigate propolis and its component caffeic acid phenethyl ester (CAPE) for their antioxidant effects on the brain tissue of rats exposed to ionizing radiation (IR). Materials and Methods: Fifty-four male albino Sprague-Dawley rats, divided into six groups, were designed as normal control group, cranial irradiation of 5 Gray alone, irradiation plus CAPE, irradiation plus propolis, control groups of propolis and CAPE. Oxidative/antioxidative status indicators, lipid peroxidation and antioxidant enzymes, were determined by biochemical methods in homogenized brain tissue of rats. Results: Malondialdehyde level, the lipid peroxidation index, in the irradiation alone group was found to be significantly increased compared to all of the other groups (p<0.001). Enzyme activities of superoxide dismutase (SOD) were 504.93, 720.70 and 659.98 for irradiation alone group, irradiation plus CAPE group and irradiation plus propolis group, respectively. Enzyme activity of SOD in the irradiation alone group was found to be significantly decreased compared to the groups received propolis or CAPE (p<0.003). Enzyme activity of glutathione peroxidase was not found statistically different among all of the groups. Conclusion: Propolis and CAPE were found to be beneficial agents in protecting brain tissue against IR-induced oxidative damage.

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A discrete MIBI avid lung lesion was found in cinematic views of myocardial perfusion imaging (MPI) of a 59 year-old woman. Interestingly, the abnormal uptake in the lung was detectable only in the rest phase images and not in the images acquired in the stress phase. MPI was performed for pre-operation cardiac risk assessment before correction surgery for spinal canal stenosis.  She had no past medical history or symptoms concerning pulmonary problems. The clinical examination of the pulmonary system was normal. MPI was reported normal but for the lung lesion she was sent for consultation with pulmonologist. The pulmonologist diagnosed the lesion was an old inflammatory/infective lesion probably secondary to tuberculosis. No histopathological examination was done. By reporting this case we intended to highlight the possibility of the effect of stress on uptake of MIBI in tumoral lesions as a tumor agent in nuclear medicine.

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