• Radiation Oncology Journal
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• v.22 no.1
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• pp.40-54
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• 2004

Purpose : Captopril (angiotension converting enzyme inhibitor) is known to have a radioproptective effect in the lungs, intestines and skin, but its effect in the heart is unclear. To investigate the radioprotectlve efiect and mechanism of captopril on the heart, the histopathological changes and immunohistochemical stains were compared with radiation alone, and radiation combined with captopril, in the rats. Materials and Methods : The histopathological changes and immunohistochemical stains ($TNF{\alpha}$, $TGF{\beta}1$, PDGF and FGF2) were examined in the radiation alone and the combined captopril and radiation groups, 2 and 8 weeks after irradiation. Each group consisted of 8 to 10 rats (Sprague-Dawley). Irradiation (12.5 Gy) was given to the left hemithorax in a single fraction. Captopril (50 mg/Kg/d) mixed with water, was given orally and continuously from the first week prior to, up to the 8th week of the experiment. Results : In the radiation alone group, the ventricle at 2 weeks after irradiation showed prominent edema (p=0.082) and fibrin deposit (p=0.018) compared to the control group. At 8 weeks, the edema was decreased and fibrosis increased compared to those at 2 weeks. The histopathological changes of the combined group were similar to those of the control group, due to the reduced radiation toxicity at 2 and 8 weeks. The endocardial fibrin deposit (p=0.047) in the atrium, and the interstitial fibrin deposit (p=0.019) and edema (p=0.042) of the ventricle were reduced significantly in the combined group compared to those in the radiation alone group at 2 weeks. The expressions of $TNF-{\alpha}$, $TGF-{\beta}1$, PDGF and FGF-2 in the radiation alone group were more increased than in the control group, especially in the pericardium and endocardium of the atrium at 2 weeks. At 8 weeks, the pericardial $TNF-{\alpha}$ and $TGF-{\beta}1$ in the radiation alone group continuously increased. The expressions of $TNF-{\alpha}$, $TGF-{\beta}1$ and PDGF were decreased in the combined group at 2 weeks. At 8 weeks, the expressions of $TNF-{\alpha}$ in the atrial and ventricular pericardia were markedly reduced (p=0.049, p=0.009). Conclusion : This study revealed that the early heart damage induced by radiation can be reduced by the addition of captopril in a rat model. The expressions of $TNF-{\alpha}$, $TGF-{\beta}1$ and PDGF were further decreased in the combined compared to the radiation alone group at both 2 and 8 weeks. From these results, it may be concluded that these cytokines probably play roles in the radioprotective mechanism of captopril from the radiation-induced heart toxicity, similarly to in other organs.

• Environmental Engineering Research
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• v.25 no.1
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• pp.29-35
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• 2020

The aim of this study was to estimate the microbial metabolic activity of indigenous soil microbes under the radon exposure with different intensity and times in the secured laboratory radon chamber. For this purpose, the soil microbes were collected from radon-contaminated site located in the G county, Korea. Thereafter, their metabolic activity was determined after the radon exposure of varying radon concentrations of 185, 1,400 and 14,000 Bq/㎥. The average depth variable concentrations of soil radon in the radon-contaminated site were 707, 860 and 1,185 Bq/㎥ from 0, 15, and 30 cm in deep, respectively. Simultaneously, the soil microbial culture was mainly composed of Bacillus sp., Brevibacillus sp., Lysinibacillus sp., and Paenibacillus sp. From the radon exposure test, higher or lower radiation intensities compared to the threshold level attributed the metabolic activity of mixed microbial consortium to be reduced, whereas the moderate radiation intensity (i.e. threshold level) induced it to the pinnacle point. It was decided that radon radiation could instigate the microbial metabolic activity depending on the radon levels while they were exposed, which could consequently address that the certain extent of threshold concentration present in the ecosystem relevant to microbial diversity and population density to be more proliferated.

• Journal of Photoscience
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• v.9 no.2
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• pp.439-441
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• 2002

Cyanobacteria are the dominant micro flora in rice-fields, contributing significantly to fertility as a natural biofertilizer. Recent studies show a continuous depletion of the stratospheric ozone layer, and the consequent increase in solar UV-B (280-315 nm) radiation reaching the Earth's surface. UV-B radiation causes reduction in growth, survival, protein content, heterocyst frequency and fixation of carbon and nitrogen in many cyanobacteria. UV -B induced bleaching of pigments, disassembly of phycobilisomal complexes, thymine dimer formation and alterations in membrane permeability have also been encounterd in a number of cyanobacteria. However, certain cyanobacteria produce photoprotective compounds such as water soluble colorless mycosporine-like amino acids (MAAs) and the lipid soluble yellow-brown colored sheath pigment, scytonemin, to counteract the damaging effects of UV-B. Cyanobacteria, such as Anabaena sp., Nostoc commune, Scytonema sp. and Lyngbya sp. were isolated from rice fields and other habitats in India and screened for the presence of photoprotective compounds. A circadian induction of the synthesis of MAAs by UV -B was noted in a number of cyanobacteria. Polychromatic action spectra for the induction of MAAs in Anabaena sp. and Nostoc commune also show the induction to be UV-B dependent peaking at 290 nm. Another photoprotective compound, scytonemin, with an absorption maximum at 386 nm (also absorbs at 300, 278, 252 and 212 nm), was detected in many cyanobacteria. In conclusion, a particular cyanobacterium having photoprotective compounds may be a potent candidate as biofertilizer for crop plants.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.17-24
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• 2019

Bacteria in the polar region are under strong light and ultraviolet radiation. In this study, we investigated the effects of light on the growth of a psychrophilic bacterium, Sphingomonas sp. PAMC 26621, isolated from an Arctic lichen Cetraria sp. The growth of the strain in the light was lower than that in the dark. Surprisingly, thiamine increased the growth of Sphingomonas sp. PAMC 26621 in M9 minimal medium under light conditions. Thiamine increased the growth of the strain in a concentration-dependent manner along with ascorbic acid. N-acetylcysteine had no effect on the growth of the strain in the light. Thiamine and ascorbic acid also increased the activities of glucose-6-phosphate dehydrogenase and superoxide dismutase. The results of this study indicate that thiamine provided by the lichen symbiosis system plays an important role in light-induced oxidative stress in this Arctic bacterium as an antioxidant. Our study provide insight into the biochemistry and physiology of Arctic bacteria under strong light and ultraviolet radiation.

• Korean journal of applied entomology
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• v.13 no.4 s.21
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• pp.245-249
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• 1974

In order to establish a dose limits for subsequent induced mutation research itl Pyricularia oryzae, X-ray sensitivity of the conidia and the vegetative hypae of the fungus, race N-1, was investigated. Conidia of the fungus irradiated with X-rays reduced significantly in spore germination inversely with radiation doses. A severe suppression of conidia germination in about $80\%$ was found at the dose of 120kR, and the rests of the conidia produce very short and lysed germ tubes. A stimulated effect was observed in the elongation of hyphae from the conidia of 10 kR irradiation at initial stage of the growth. The radiosensitivity of hyphae was exremely higher than that of conidia with the increase of radiation doses. It was also recognized that the frequency of X-ray induced mutation in pathogenicity was directly proportional to radiation doses.

• Molecules and Cells
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• v.25 no.2
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• pp.272-278
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• 2008

The carbon-ion beam (CIB) generated by the heavy-ion medical accelerator in Chiba (HIMAC) was targeted to 7-day-old rice. Physiological parameters such as growth, and gene expression profiles were examined immediately after CIB irradiation. Dose-dependent growth suppression was seen three days post-irradiation (PI), and all the irradiated plants died by 15 days PI. Microarray (Agilent rice 22K) analysis of the plants immediately after irradiation (iai) revealed effects on gene expression at 270 Gy; 353 genes were up-regulated and 87 down-regulated. Exactly the same set of genes was affected at 90 Gy. Among the highly induced genes were genes involved in information storage and processing, cellular processes and signaling, and metabolism. RT-PCR analysis confirmed the microarray data.

• Biomolecules & Therapeutics
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• v.12 no.3
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• pp.157-164
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• 2004

DA-3711 is a novel anti-wrinkle agent containing growth factors derived from culture medium of artificial human skin. Photoprotective effect by DA-3711 against chronic UVB (ultraviolet B)-induced skin damage was investigated in hairless mice model. Methods: After hairless mice were irradiated to induce photodamage for 8 weeks with UVB, grouped mice were treated topically once a day with lotion base, DA-3711 (30% or l5%), Cylasphere retinol$^{\circed{R}}$ (2500 I.U.), NouriCel$^{\circed{R}}$ along with concomitant exposure to UVB for further 8 weeks. Then mice were sacrificed to assess photodamage-protective effect by replica analysis, biochemistry and histology. DA-3711 of 30% lotion significantly reduced UVB radiation-induced wrinkling, histological alterations and increased collagen contents. Whereas DA-3711 of l5% lotion and NouriCel$^{\circed{R}}$ treatment showed a partial protective effect on skin wrinkle, epidermal and dermal thickness, and collagen content, Cylasphere retinol$^{\circed{R}}$ showed no protective effects. These results demonstrate that topical application of DA-3711 can alleviate UVB-induced photodamage and potentially be used for reduction of UVB-induced photodamage.

• Radiation Oncology Journal
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• v.9 no.1
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• pp.7-15
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• 1991

Pentoxifylline (PENTO) has been known to improve RBC fluidity, and thus improve the flux of RBC through narrow capillaries. Additionally, PENTO also decreases the $O_2$ affinity of hemoglobin by increasing 2,3-DPG levels, thereby increasing the $O_2$ release from RBC. Nicotinamide (NA) has been reported to decrease the number of acutely hypoxic cells in tumors by temporarily increasing tumor blood flow. Therefore, the purpose of this study was to examine whether the combination of PENTO and NA (PENTO+NA) would reduce the radioresistance of the Fsall murine fibrosarcoma by oxygenating the hypoxic cells. We obsewed a significantly enhanced radiation-induced growth delay of the FSaII tumors by PENTO+NA. Thus the enhancement ratio was between 2.5 and 2.8 in growth delay assay. The $TCD_{50}$ of control tumors was about 57 Gy, but that of PENTO+NA treated tumors was about 32Gy. Thus $TCD_{50}$ was modified by a factor of 1.8. We also observed that PENTO+NA exerted no effect on the radiation-induced skin damage after the legs without bearing tumors were exposed to X-irradiation. In order to clarify radiosensitizing effects of PENTO+ NA, changes in tumor blood flow and intratumor pOf were measured using laser Doppler flowmetry and $O_2$ microelectrode methods. The tumor blood flow significantly increased at 10 min. after injection of PENTO+ NA. Furthermore, we also found that PENTO+ NA significantly increased intratumor $pO_2$ from 8 to 19 mmHg. We concluded that PENTO+MA was far more effective than NA alone or PENTO alone. The increase in the response of tumors in vivo to X-irradiation appeared to be due mainly to an increase in the tumor oxygenation. Further studies using various concentrations of PENTO alone and in combination with NA to obtain better sequencing and maximal radiosensitization are warranted.

• Journal of Microbiology and Biotechnology
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• v.21 no.3
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• pp.252-255
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• 2011

Both Escherichia coli (E. coli) and Salmonella enterica serovar Typhimurium (S. Typhimurium) have a tdc operon that encodes enzymes involved in a metabolic pathway for the degradation of L-serine and L-threonine. However, S. Typhimurium does not have the tdcR gene, which is a positive regulator in E. coli. In the present study, transcriptional analysis revealed that tdcA expression in E. coli is higher under anaerobic than aerobic growth conditions, but the opposite is true in S. Typhimurium. Interestingly, a tdcR mutant strain of E. coli showed a similar expression pattern to that observed in S. Typhimurium and was also induced by anaerobic shock. These results suggest that the induction of tdcA expression by anaerobic conditions is observable when tdcA expression is low owing to the absence of TdcR.

• Radiation Oncology Journal
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• v.29 no.2
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• pp.83-90
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• 2011

Purpose: Flavopiridol enhanced radiation-induced apoptosis of cancer cells in our previous in vitro study. The purpose of this study was to assess if flavopiridol could enhance the radioresponse of mouse mammary tumors in vivo. Materials and Methods: Balb/c mice bearing EMT-6 murine mammary carcinoma were treated with flavopiridol only, radiation only, or both for 7 days. Flavopiridol was administered 2.5 mg/kg twice a day intraperitoneally (IP). Radiation was delivered at a 4 Gy/fraction at 24-h intervals for a total dose of 28 Gy. Tumor volume was measured and compared among the different treatment groups to evaluate the in vivo radiosensitizing effect of flavopiridol. Tumors were removed from the mice 20 days after treatment, and TUNEL and Immunohistochemical stainings were performed. Results: Significant tumor growth delay was observed in the radiation only and combined treatment groups, when compared with the control group. However, there was no significant difference between the tumor growth curves of the control and flavopiridol only group or between the radiation only and combination treatment group. Apoptotic cells of different treatment groups were detected by terminal deoxynucleotidyl transferase-medicated nick end labeling (TUNEL) staining. The expressions of Ku70 in tumor tissues from the different groups were analyzed by immunohistochemistry. Similarly, no significant difference was found between the apoptotic rate or Ku70 expression among the different treatment groups. Conclusion: Flavopiridol did not show evidence of enhancing the radioresponse of mouse mammary tumors in this study.