• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.29 no.2
• /
• pp.435-449
• /
• 1999

Purpose : The study was aimed to detect the differences in the cell viability and the apoptosis induction after irradiation on normal and tumorigenic cells. Materials and Methods : The study. that was generated for two human normal cells(RHEK, HGF-l) and two human tumor cells(KB. HT-1080). was tested using MTT assay at 1 day and 3 day after irradiation and TUNEL assay under confocal laser scanning microscope at 1 day after irradiation. Single irradiation of 0.5. 1, 2. 4. and 8Gy were applied to the cells. The two fractions of 1. 2. 4. and 8Gy were separated with a 4-hour time interval. The irradiation was done with 5.38Gy/min dose rate using Cs-137 irradiator at room temperature. Results and Conclusions : 1. In 3-day group. the cell viability of HGF-1 cell was significantly decreased at 2. 4 and 8Gy irradiation, the cell viability of KB cell was significantly decreased at 8Gy irradiation and the cell viability of HT-I080 cell was significantly decreased at 4 and 8Gy irradiation. 2. There was significant difference between RHEK and KB cell line in the cell viability of 3-day group at 8Gy irradiation. There was significant difference between RHEK and HGF-1 cell line in the cell viability of 3-day group at 4 and 8Gy irradiation. 3. There was a significantly decreased cell viability in 3-day group than those in 1-day group at 2. 4 and 8Gy on HGF-1 cell. at 4 and 8Gy on HT-I080 cell. at 8Gy on KB cell. 4. We could detect DNA fragmented cells only on KB cell. Number of apoptotic cells of KB cell was significantly increased at 4 and 8Gy irradiation. However, there was no correlation between cell viability and apoptosis. 5. On all 4 cell lines, there were no differences between single and split irradiation method in cell viability and apoptosis.

• Journal of Photoscience
• /
• v.9 no.2
• /
• pp.138-141
• /
• 2002

A photo-labile compound which is bioinactive but, upon irradiation with light, yields bioactive species is called as "caged compound". Photolysis of caged compounds generating bioactive species, has become a general method to produce a desired amounts of bioactive species in the specific time interval at the desired place or area of the target biological systems. For this purpose, we designed and synthesized caged hydroxyl radical., "Photo-Fenton Reagent" NP-IIl. NP-IIl has a strong absorption maximum at 377 nm and yields hydroxyl radicals upon UV light irradiation. The antioxidant activity of the ${\alpha}$ -lipoic acid and other naturally occurring compounds has been examined by using NP-IIl as a molecular probe. For example, upon photoirradiation of NP-lII with BSA or apolipoprotein of human low density (LDL), the significant oxidative modifications were observed in both cases. The oxidation was completely suppressed in the presence of ${\alpha}$-lipoic acid, which clearly demonstrates the strong hydroxyl radical scavenging activity of ${\alpha}$-lipoic acid. Other applications of NP-lII will also be described

• Korean Journal of Metals and Materials
• /
• v.47 no.12
• /
• pp.819-827
• /
• 2009

This work is concerned with a statistical analysis of factors affecting the irradiation-assisted stress corrosion cracking (IASCC) of austenitic stainless steels for core internals of pressurized water reactors (PWR). The microstructural and environmental factors were reviewed and critically evaluated by the statistical analysis. The Cr depletion at grain boundary was determined to have no significant correlation with the IASCC susceptibility. The threshold irradiation fluence of IASCC in a PWR was statistically calculated to decrease from 5.799 to 1.914 DPA with increase of temperature from 320 to $340^{\circ}C$. From the analysis of the relationship between applied stress and time-to-failure of stainless steel components based on an accelerated life testing model, it was found that B2 life of a baffle former bolt exposed to neutron fluence of 20 and 75 DPA was at least 2.5 and 0.4 year, respectively, within 95% confidence interval.

• Radiation Oncology Journal
• /
• v.21 no.1
• /
• pp.75-81
• /
• 2003

Purpose : This study quantitatively evaluated the apoptosis In human peripheral blood lymphocytes using flow cytometry, and investigated the possibility of using this method, with a small amount of blood, and the time and dose dependence of radiation-induced apoptosls. Materials and Methods : Peripheral blood lymphocyes were isolated from the heparinized venous blood of 11 healthy volunteers, 8 men and 3 women, with each 10 ml of blood being divided Into IS samples. The blood lymphocytes were Irradiated using a linear accelerator at a dose rate of 2.4 Gy/min, to deliver doses of 0.5, 1, 2 and S Gy. The control samples, and Irradiated cells, were maintained in culture medium for 24, 48 and 72 hours fellowing the Irradiation. The number of apoptotic cells after the in vitro X-irradiation was measured by flow cytometry after Incubation periods of 24, 48 and 72 hours. We also observed the apoptotic cells using a DNA fragmentation assay and electron microscopy. Results : The rate oi spontaneous apoptosis increased in relation to the time interval following irradiation (1.761 ${\pm}$0.161, 3.563${\pm}$0.554, 11.098${\pm}$2.849, at 24, 48, and 72 hours). The apoptotli cells also increased In the samples irradiated with 0.5, 1, 2 and 5 Gy, In a radiation dose and time interval after Irradiation manner, with the apoptosls being too great at 72 hours after Irradiation. The dose-response curves were characterized by an Initial steep Increase In the number of apoptotic cells for Irradiation doses below 2 Gy, with a flattening of the curves as the dose approached towards 5 Gy. Conclusion :The flow cytometric assay technique yielded adequate data, and required less than 1 mL of blood. The time and dose dependence of the radiation-induced apoptosis, was also shown. It is suggested that the adequate time Interval required for the evaluation of apoptosis would be 24 to 48 hours after blood sampling.

• Korean Journal of Environmental Agriculture
• /
• v.18 no.1
• /
• pp.41-47
• /
• 1999

To investigate the combined effect of gamma ray irradiation and NaCl treatment on Tradescantia somatic cell pink mutations, potted plants of Tradescantia 4430 were evenly sprayed with NaCl solution(170mM) 24 hours before irradiation(NaCl+${\gamma}$) and after irradiation(${\gamma}$+NaCl). Irradiation doses were 0.3, 0.5, 1.0 and 2.0 Gy of gamma-ray. The plants irradiated only with gamma radiation were used as control group(CT). Frequency of pink mutation increased linearly with irradiation close and the peak interval of elevated mutation frequencies appeared during 6∼12 days aver irradiation in all the experimental groups. The slope of dose-response curve in CT was 5.99($r^2$=0.99), while it were 4.55($r^2$=0.98) in NaCl+${\gamma}$ and 4.33($r^2$=0.99) in ${\gamma}$+NaCl. It seemed that pre- and post-treatment of NaCl had a protective effect it against radiation-induced cell damages since it decreased the slope value by more than 24%. It is suggested that protective effect on DNA damages can be invoked in irradiated stamen hair cells by NaCl treatment.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.48 no.2
• /
• pp.193-199
• /
• 2015

We observed that the growth and physiological change in Haliotis discus discus by low-dose irradiation with gamma ray.Irradiation with gamma ray was undertaken by using the low-level irradiation facility ($^{60}CO$) in cooperation with the Institute of Nuclear Science and Technology at Jeju National University. The parent abalones were attached one by one and then fixed by using the rubber band to the front side of the fabricated case for irradiation with gamma ray. The experimental plots of irradiation with gamma ray were set as 10, 15, 20 and 25 Gy and the 25 female abalones and 10 male abalones were utilized for each experimental plot. The sperms and eggs were fertilized by setting an interval for each dose to prevent mixing with other experimental plots when fertilizing the sperms and eggs for each dose of irradiation with gamma ray. As for the fertility, it was confirmed to be 85% the control and 10 Gy groups, whereas it was found to be 80%, 65% and 50% in the 15 Gy, 20 Gy and 25 Gy groups, respectively. As a conclusion, the hatching rate and attachment rate were higher at 10 and 15 Gy than the other experimental plots, and the growth rate was higher at 20 Gy than the other experimental plots. Also the changes in lysozyme activity in accordance with the stress of water temperature were found to have a significant increase in the other experimental plots as compared with the control plot at the end of 0 h. The changes in lysozyme activity have remained constant in all the experimental plots at the end of 12 h. These results allowed us to confirm that lysozyme was undertaking the biodefense action by reacting sensitively to the stress of water temperature in the control experimental plot. As for the other experimental plots, they are believed to avoid the biodefense mechanism due to the high degree of anti-parasite mechanism and anti-viral mechanism. Thus, it is believed that it would be imperative to conduct development and research on breeds that were potent for environmental tolerance by applying the method of irradiation with gamma ray to other marine animals and plants.

• Archives of Pharmacal Research
• /
• v.20 no.3
• /
• pp.212-217
• /
• 1997

Induction of an adaptive response to ionizing radiation in mouse lymphoma (EL4) cells was studied by using cell survival fraction and apoptotic nucleosomal DNA fragmentation as biological end points. Cells in early log phase were pre-exposed to low dose of ${\gamma}$-rays (0.01 Gy) 4 or 20 hrs prior to high dose ${\gamma}$-ray (4, 8 and 12 Gy for cell survival fraction analysis; 8 Gy for DNA fragmentation analysis) irradiation. Then cell survival fractions and the extent of DNA fragmentation were measured. Significant adaptive response, increase in cell survival fraction and decrease in the extent of DNA fragmentation were induced when low and high dose .gamma.-ray irradiation time interval was 4 hr. Addition of protein or RNA synthesis inhibitor, cycloheximide or 5,6-dichloro-1-.betha.-d-ribofuranosylbenzimidazole (DRFB), respectively during adaptation period, the period from low dose ${\gamma}$-ray irradiation to high dose ${\gamma}$-ray irradiation, was able to inhibit the induction of adaptive response, which is the reduction of the extent DNA fragmentation in irradiated EL4 cells. These data suggest that the induction of adaptive response to ionizing radiation in EL4 cells required both protein and RNA synthesis.

• Journal of the Korean Society of Radiology
• /
• v.15 no.6
• /
• pp.841-847
• /
• 2021

Related institutions that use radiation are diverse in Korea, such as research, medical care, and education. Recently, the number of examinations and visits to medical institutions is increasing. As a result, the number of radiological examinations in medical institutions is increasing. Radiation safety management is necessary as well as exposure of radiation workers. For safety management, first of all, it is necessary to wear the personal exposure dosimeter correctly and measure it accurately after wearing it. This study tries to evaluate and verify the measurement straightness of PLD devices by radiation of a diagnostic generator. Radiation division irradiation time interval was measured after irradiating 10 times at 10, 30, and 60 sec and irradiating the irradiation distance from 30 to 100 cm at 10 cm intervals to measure the change in absorbed dose depending on the distance. As a result, there was no difference in absorbed dose by time interval. This is considered to be helpful in various studies by using a diagnostic generator for the study of high absorbed dose.

• The Journal of Natural Sciences
• /
• v.9 no.1
• /
• pp.45-52
• /
• 1997

We have examined the effects of low concentrations of MNNG, alkylating agent, in survival and mutagenesis in Aspergillus nidulans. Pretreatments of cells with nontoxic and submutagenic doses of MNNG did not reduce the cytotoxic and mutagenic effects of exposure to a high concentration of drug. The results imply that adaptive responses on survival and mutagenesis for MNNG treatments do not occur in Aspergillus nidulans. In the first mitotic cell cycle during germination, the sensitivity to MNNG has been investigated at hourly time interval, and compared with that for UV irradiation. In both UV and MNNG treatments, the sensitivity increased till S cell stage, and decreased while DNA replication continued. Different from that show for UV irradiation, lethality to MNNG reached to the maximum at G2 cell stage.

• The Korean Journal of Cytopathology
• /
• v.4 no.2
• /
• pp.87-92
• /
• 1993

The effect of Roentgen rays on carcinoma of the cervix has long been of great interest to both radiologists and gynecologists. Since most cervical carcinomas are treated by irradiation, any additional knowledge either concerning the radiosensitivity of cervical tumors or their ultimate prognosis would be of value. The vaginal smear is considered to be one of convenient and rapid methods to study the effects of radiation on cervical malignancy. We observed morphologic changes in 297 cytologic preparations obtained from 60 patients who had underwent irradiation for cancer of the cervix. With the morphologic parameters such as cytoplasmic vacuolization, cytoplasmic basophilia, multinucleated giant cell formation, polymorphonuclear leucocytes (PMNL) sticking and postradiation dysplasia, we analyzed the findings in relation to the follow up time interval. The most common effect was the cytoplasmic vacuolization with basophilia of basaloid cells, which were noted in more than 90% of followed patients. The multinucleated giant ceil formation and PMNL stickering were noted in 38 cases(63%) and 48 cases(80% ) respectively. The differential diagnosis of postradiation dysplasia from recurrent or persistent carcinoma, reparative atypical cells, and regressing tumor cells was difficult and further study seems to be needed to clarify the more accurate morphologic features and biologic behavior.