ABSTRACT
Ionizing radiation induces oxidative stress due to free radicals production. The in vitro study has shown that tender coconut water (TCW) of West Coast tall variety exhibits potent antioxidant property. Here, we attempted to evaluate the potency of TCW in reducing radiation induced oxidative stress in the mice model. The LD50/30 dose of electron beam radiation (EBR) for Swiss albino mice was assessed and was found to be 9.33Gy. Therefore, a sublethal dose of 6Gy was selected for further intervention studies to assess the levels of antioxidants. To evaluate the effective dose, the mice were irradiated with a lethal dose of 10Gy with the oral intervention of 50, 100 and 200 µL of TCW/20 g body wt. of mice. Findings of the study suggest that 100 µL/20 g body wt. was found to be effective in decreasing the mortality of irradiated mice. Further, intervention with TCW significantly increased the antioxidant levels compared to that of radiation control group. The results suggest that TCW exhibits radioprotective activity by potentiating the antioxidant levels in mice exposed to a sublethal dose of whole body EBR.
ABSTRACT
Lichens are self-sustaining symbiotic organism with algae, fungi and bacteria, survives even in adverse environmental conditions. However, how these symbionts solitarily survive while subject to irradiation has not been studied yet. Here, we focused on the lichen associated bacteria possessing plant growth promoting (PGP) traits to withstand the low dose e-beam irradiation and improvement of strains for PGP traits. Lichen associated bacterial isolates (GSL-01 to 11) majorly Enterobacter cloacae and Providencia rettgeri were subjected to e-beam irradiation (2-10 Gy) and their PGP activities were evaluated. Among these, only 3 isolates of E. cloacae GSL-01, 07 and 11 and P. rettgeri GSL-09 showed the potential to withstand low dose e-beam irradiation (2-8 Gy with 10 Hz), along with isolates GSL-07 and GSL-09 resulted in enhanced PGP activity. In addition, e-beam irradiation at 10 Gy with 50 Hz adversely affected PGP properties; perhaps due to the genetic instability of bacteria by irradiation resulted in the loss of PGP properties. Contrastingly, irradiated P. rettgeri (GSL-09) and E. cloacae (GSL-07) showed elevated nitrogen fixation and IAA production compared to the non-irradiated bacterial isolates. Therefore, these potential lichenized bacterial isolates (GSL-01, 07, 09 and 11) perhaps used for plant growth promoters (after validation), especially in adverse environmental condition, as these isolates showed the tolerance to low dose e-beam irradiation. Further, this study elaborates the current knowledge of low dose e-beam irradiation effect at different doses on PGP traits of lichenized bacteria.
ABSTRACT
Objective: To explore the effect of hydroalcoholic extract of Cynodon dactylon on the whole body radiation-induced oxidative status of the cerebellum and cognitive impairments in mice. Methods: Swiss albino mice were randomly divided into the control group, radiation control group, low dose and high dose Cynodon dactylon extract treated groups and pre-treated with Cynodon dactylon extract before irradiation. Cynodon dactylon extract was administered for 7 d daily in low dose (0.25 g/kg) and high dose (1 g/kg). On day 7, mice were irradiated with a sublethal dose of 5 Gy gamma rays. Motor coordination was assessed by elevated rotarod test and spatial memory was studied by water maze test. Subsequently, biochemical markers (glutathione, lipid peroxidation and nitric oxide levels) in the cerebellum were evaluated. Results: The gamma irradiated group showed significant impairment in motor coordination and spatial memory compared to normal mice. Mice treated by Cynodon dactylon extract prior to gamma radiation showed good improvement in both paradigms compared to the radiation control group. Moreover, glutathione level was increased, while lipid peroxidation and nitric oxide levels were significantly reduced in mice receiving low dose and high dose of Cynodon dactylon extract compared to the radiation control group. Conclusions: The present study suggests the neuroprotective role of Cynodon dactylon against radiation-induced cognitive impairment and oxidative stress on the cerebellum of mice.
ABSTRACT
Background: Oral health diseases are common in all regions of the world. Mouth rinses are widely used generally by population as a port of daily oral care regimen. In addition to antimicrobial activity, mouth rinses possess certain cytotoxic effects. Electron‑beam (E‑beam) radiation is a form of ionizing energy known to induce structural, physical, and chemical changes in irradiated products. In this study, the modulatory effects of E‑beam in irradiated mouth rinses were evaluated for its biological activities. Materials and Methods: The antimicrobial activities of nonirradiated and irradiated mouth rinses were evaluated for its antimicrobial and antibiofilm activities against oral pathogens, Enterococcus faecalis, Streptococcus mutans, Staphylococcus aureus, and Candida albicans. The antimicrobial activity was evaluated by disc diffusion method and antibiofilm activity was evaluated by O’Toole method. The cytotoxicity was evaluated against human gingival fibroblast (HGF) cells by 3‑(4, 5 Dimethythiazol‑yl)‑2,5‑Diphenyl‑tetrazolium bromide assay. Results: Colgate Plax (CP) exhibited the antimicrobial activity against the tested pathogens, and a significant (P < 0.05) increase was observed against S. aureus at 750 Gy irradiation. Further, CP significantly (P < 0.05) suppressed S. mutans, S. aureus, and C. albicans biofilm. Listerine (LS) inhibited S. mutans and C. albicans biofilm. Whereas irradiated CP and LS significantly (P < 0.05) suppressed the biofilm formed by oral pathogens. The suppression of biofilm by irradiated mouth rinses was dose‑ and species‑dependent. There was no significant (P > 0.05) difference in the cytotoxicity of irradiated and nonirradiated mouth rinses on HGF cells. However, an increased percentage viability of HGF cells was observed by mouth rinses irradiated at 750 Gy. Conclusion: The E‑beam irradiation enhanced the antibiofilm activity of mouth rinses without modifying the cytotoxicity.
ABSTRACT
Aim: The aim of this study is to investigate whether dental nanocomposite Filtek Z350 XT and Ceram X-duo can benefit from electron beam irradiation in order to achieve increased flexural strength Place and Duration of Study: Department of Conservative Dentistry and Endodontics, A. B. Shetty Memorial Institute of Dental Sciences, Nitte University, Deralakatte, Mangalore, India and Microtron Centre; Department of Physics Mangalore University; Mangalore, India between May 2011 to March 2014. Materials and Methods: Materials were prepared on rectangular bar shaped specimens of 25-×2-×2-mm according to ISO standard -4049. Electron beam irradiation dose selected for the study were 1KGy, 3KGy and 5KGy. In total, 48 specimens were fabricated and divided into 4 groups based on radiation dose group I (non-radiated), group II (1KGy), group III (3KGy), group IV (5KGy) with 12 specimens in each. After 24 hours, specimens were subjected to 3-point bend test on a universal uniaxial servo mechanical testing machine. Statistical Analysis: Performed using one way ANOVA and inter group comparisons were done using tukeys multiple comparision. ‘P’ value<0.05 was considered statistically significant. Results: Flexural strength of Filtex Z350 XT before radiation was170.89±9.07.Flexural strength of Filtex Z350 XT after irradiation with 1KGy, 3KGy and 5KGy was found to be 269.06±94.91, 326.53±54.74 and 377.64±74.5 respectively. P value statistically significant (P<0.0001). Flexural strength of Ceram X duo before radiation was120.14±7.12.Flexural strength of Ceram X duo after irradiation with 1KGy, 3KGy and 5KGy was found to be 206.27±76.38, 177.31±67.35 and 229.33±59.15 respectively. P value statistically significant (P<0.0001). Conclusion: It can be concluded that electron beam irradiation can be used as a tool to modify the present day dental materials for enhancing their mechanical properties.
ABSTRACT
Aim: The aim of this study was to evaluate the cytotoxicity of three resin luting agents Rely X luting cement, Rely X luting 2 cement and Clearfil SA luting cement before and after electron beam irradiation. Materials and Methods: Growth and maintenance of cell cultures of human pulp cells was done in Dulbecco’s modified Eagle’s Medium (DMEM). The test samples were divided into two Categories: Irradiated Category and Non-radiated Category. Samples in Irradiated category were exposed to electron beam radiation at 200Gy. Three subgroups of radiated category and non radiated category were made. All the samples were subjected to MTT assay and spectrophotometric analysis and their cytotoxicity was assessed. Statistical analysis was done using t test. Results: Evaluation of Rely X luting Cement showed that radiated samples of powder, liquid and set cements showed decreased cell viability than non radiated samples. In Case of Rely X luting 2 cement, radiated samples showed increased cell viability for Paste A and Paste B samples. But in set material, irradiated samples showed decreased cell viability as compared to non radiated samples. For Clearfil SA luting Cement, Paste B showed increased cell viability for radiated samples. Paste A and Set cement of radiated samples showed decreased cell viability than non radiated samples. Conclusion: In the present study , the increased cytotoxicity of irradiated samples may be due to increase in the release of unbound monomers which may be due to chain breakage after irradiation and a reduction in the cytotoxicity which may be due to the cross linking of unbound monomers during irradiation.