• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.5
• /
• pp.804-809
• /
• 1996

The bactericidal effectiveness of radiation alone or in combination with heat against 8 strains associated with food hygiene were evaluated. In the case of radiation alone, D$_{10}$ values of micro-organisms were 0.14~0.48 kGy, and inactivation factors were 4.54~21.43 at the doses of 2~3 kGy. Escherichia coli was the most sensitive among the tested strains, resulting in a D$_{10}$ value of 0.14 kGy. D$_{min}$ values of tile strains were 10~40 minutes at $50\pm1^{\circ}C,$ and 5~10 minutes at $60\pm1^{\circ}C.$ Combination with heat and radiation showed D$_{10}$ values of 0.04~0.31. Inactivation factors were 6.45~75 at the doses of 2 to 3 kGy. Therefore, heat treatment prior to irradiation significantly increased mactivation rate by increasing radiation sensitivity of microorganisms.ganisms.

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

• Radiation Oncology Journal
• /
• v.4 no.1
• /
• pp.1-13
• /
• 1986

In order to clarify the effect of radiation on the mouse jejunal crypt cells by combined administration of administration and radiation and also to evaluate the enhancing effect of adriamycin, the authors performed this study by delivering single irradiation of 1,000 to 1,600 rad to the whole abdomen of mice by cobalt-60 teletherapy unit. In combination with adriyamycin treatment groups, the drug was administered as single dose of 10 mg/kg either 2 hours before or 4 hours after graded single dose,900 to 1,400 rad, of irradiation. The authors studied the quantitative changes of intestinal crypt cells by microcolony survival assay technique and the morphological changes of small intestinal villi by scanning electron microscope in mice following to combined therapy with adriamycin and irradiation, The average number of jejunal crypts per circumference was $130{\pm}16$ in control group. The mean lethal dose(Do) of each irradiation alone and combined therapy groups 2 hours before and 4 hours after irradiation, were 160, 170, and 170 rad in cell survival curves, respectively. The dose effect factor(DEF) of adriamycin in each groups of pre-irradiation and post-irradiation were 1.19 and 1.26, respectively. The conical shaped villi were noted on 1,200 rad in irradiation alone group and 1,000 rad in combined groups. For the proper clinical application we must be careful of the radiation injury to small bowel when the anticancer chemotherapy and radiation therapy to the abdomen and pelvic area are used as combined therapeutic modality.

• Radiation Oncology Journal
• /
• v.28 no.4
• /
• pp.219-223
• /
• 2010

Purpose: To test the radiosensitizing effect of the newly synthesized novel histone deacetylase inhibitor, SK-7041 in vivo. Materials and Method: The RIF-l cell line was implanted into the back of a 6-week-old female C3H mouse, intradermally, The mice were grouped into control, drug, radiation (RT), and RT+drug group. SK-7041, 4 mg/kg was administered intraperitoneally for six cycles every 12 hours for mice in the drug and RT+drug group, An identical volume of phosphate buffered saline (PBS) was administered at the same frequency to mice in the control and RT groups. A single 5 Gy fraction was delivered to mice in RT and RT+drug group 6 hours after the fourth delivery. The volume of the implanted tumor was measured every 2~3 days to formulate the growth delay curve. Results: For the control, drug, RT, and RT +drug groups, the average duration for implanted tumor to reach a volume of $1,500mm^3$ was 10 days, 10 days, 9 days, and 12 days, respectively. Moreover, the tumor volume on D14 was $276.7mm^3$, $279.9mm^3$, $292.5mm^3$, and $185.5mm^3$, respectively (p=0.0004). The difference for the change in slope for the control and drug versus the RT and RT+drug groups were borderline significant (p=0.0650). Conclusion: The results of this study indicate that SK-7041 has a radiosensitizing effect for the RIF-1 cell line in vivo at a low concentration and this effect may be synergistic. Implementing this result to clinical trial is warranted.

• Radiation Oncology Journal
• /
• v.7 no.2
• /
• pp.149-156
• /
• 1989

Multicellular tumor spheroids of HeLa cells have been grown in a static culture system. Samples of spheroids were exposed for 2 h to graded concentration of cis-platinum and its analogue, carboplatin, and then response assayed by survival of clonogenic cells. The purpose of present experiment is to clarify the effectiveness of these platinum compounds and to evaluate intrinsic radiosensitivity of cells using spheroids of HeLa cells as an experimental in vitro model. Variations of the drug sensitivity of monolayers as well as spheroids were also evaluated in cell-survival curves. In cis-platinum concentration-survival curve, there was a large shoulder extending as far as $Cq=3.4{\mu}M$, after which there was exponential decrease in survival curve having a Co Value of $1.2{\mu}M$ in spheroids. While the Co for the spheroids was essentially no significant change, but Cq value was larger than that of monolayers. This suggest that the effect of cis-platinum is greater En the monolayer with actively proliferaing cells than hypoxic one. In the carboplatin concentration-survival curves, the Co value of spheroids was $15.0{\mu}M$ and the ratio with the Co from monolayer cell $(32.5{\mu}M)$ was 0.40, thus indicating that the spheroids had a greater sensitivity to carboplatin than monolayers. Therefore, the effect of carboplatin is mainly on the deeper layers of spheroids acting as hypoxic cell sensitizer. The enhanced effect was obtained for monolayer cells using combined X-ray and carboplatin treatment 2 hours before irradiation. The result shown in isobologram analysis for the level of surviving fraction at 0.01 indicated that the effect of two agents was trusty supra-additive. From this experimental data, carboplatin has excited much recent interest as one of the most promising, since it is almost without nephrotoxicity and causes less gastrointestinal toxicity than cis-platinum. Interaction between carboplatin and radiation might play an important role for more effective local tumor control.

• Radiation Oncology Journal
• /
• v.21 no.3
• /
• pp.207-215
• /
• 2003

Purpose: Extracellular signal-regulated kinase (ERK), which is part of the mitogen-activated protin kinase cascade, opposes initiation of the apoptotic cell death which is programmed by diverse cytotoxic stimuli. In this regard, the inhibition of ERK may be useful in improving the therapeutic efficacy of established anticancer agents. Materials and Methods: Murine hepatocarcinoma, HCa-I is known to be highly radioresistant with a TCD50 (radiation dose yield in $50\%$ cure) of more than 80 Gy. Various anticancer drugs have been found to enhance the radioresponse of this particular tumor but none were successful. The objective of this study was to explore whether the selective inhibition of MEK could potentiate the antitumor efficacy of radiation in vivo, particularly in the case on radioresistant tumor. C3H/HeJ mice hearing $7.5\~8\;mm$ HCa-I, were treated with PD98059(intratumoral injection of $0.16\;\mug/50\;\mul$). Results: Downregulation on ERK by PD98059 was most prominent 1h after the treatment. In the tumor growth delay assay, the drug was found to Increase the effect of the tumor radioresponse with an enhancement factor (EF) of 1.6 and 1.87. Combined treatment of 25 Gy radiation with PD98059 significantly increased radiation induced apoptosis. The peak apoptotic index (number on apoptotic nuclei in 1000 nuclei X100) was $1.2\%$ in the case of radiation treatment alone, $0.9\%$ in the case of drug treatment alone and $4.9\%,\;5.3\%$ in the combination treatment group. An analysis of apoptosis regulating molecules with Western blotting showed upregulation of p53, p$p21^{WAF1/CIP1}\;and\;Bcl-X_s$ in the combination treatment group as compared to their levels in either the radiation alone or drug alone treatment groups. The level of other molecules such as $Bcl-X_L4, Bax and Bcl-2 were changed to a lesser extent. Conclusion: The selective inhibition of MEK in combination with radiation therapy may have potential benefit in cancer treatment.

• Korean Journal of Environmental Agriculture
• /
• v.19 no.4
• /
• pp.324-327
• /
• 2000

Soybean (Glycine max L. cv. Hwangkeum) seeds were irradiated with the dose of $0{\sim}20$ Gy to investigate the effect of the low dose ${\gamma}-ray$ radiation on the early growth and resistance to subsequent high dose of radiation. Germination rate was not enhanced in the seeds irradiated with low dos ${\gamma}-ray$ but plant height and fresh weight increased in the low dose irradiation group. The optimal radiation dose for the growth increasing was 8 Gy in soybean plant. Growth inhibition of soybean plants by high dose radiation was noticeably reduced by pre-irradiation of low dose radiation, Resistance to subsequent high dose of radiation was effective in 8 Gy and 20 Gy irradiation group.

• Korean Journal of Food Science and Technology
• /
• v.10 no.1
• /
• pp.88-91
• /
• 1978

When the food poisoning bacteria Salmonella enteritidis and S. typhimurium were treated with radiation (cobalt-60 r-rays) and heat (10 minutes at $45^{\circ}C\;or\;50^{\circ}C$), their sterilizing effect was revealed differently depending on the order of treatments. Post-irradiation heating showed a synergistic effect whereas pre-irradiation heating revealed the opposite effect and the effects differed slightly with heating temperature.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 1976.10a
• /
• pp.187.2-187
• /
• 1976

시판 고추가루에서 미생물을 분리하여 세균 5종과 곰팡이 13종을 동정하였고 코발트-60 감마선에 대한 이들 균주의 치사율 (D$_{10}$ 값)을 조사하였다. 또한 고추가루에 0-1,000 krad의 감마선을 처리하고 저장중 미생물의 증식여부를 관찰한 결과 세균의 발육감소를 가져왔다.

• Radiation Oncology Journal
• /
• v.11 no.1
• /
• pp.35-42
• /
• 1993

The dose response of the number of micronuclei in cytokinesis-blocked (CB) lymphocytes after in vitro irradiation with $\gamma$-rays and neutrons in the 5 dose ranges was studied for a heterogeneous population of 4 donors. One thousand binucleated cells were systematically scored for micronuclei. Measurements performed after irradiation showed a dose-dependent increase in micronuclei (MN) frequency in each of the donors studied. The dose-response curves were analyzed by a linear-quadratic model, frequencies per 1000 CB cells were ($0.31{\pm}0.049$)D+($0.0022{\pm}0.0002)D^2+(13.19{\pm}1.854) (r^2=1.000,\;X^2=0.7074,\;p=0.95$) following $\gamma$ irradiation, and ($0.99{\pm}0.528$)\;D+(0.0093{\pm}0.0047)\;D^2+(13.31{\pm}7.309)\;(r^2=0.996,\;X^2=7.6834,\;p=0.11) following neutrons irradiation (D is irradiation dose in cGy). The relative biological effectiveness (RBE) of neutrons compared with $\gamma$-rays was estimated by best fitting linear-quadratic model. In the micronuclei frequency between 0.05 and 0.8 per cell, the RBE of neutrons was $2.37{\pm}0.17$. Since the MN assay is simple and rapid, it may be a good tool for evaluating the $\gamma$-ray and neutron response.