• Journal of Radiation Protection and Research
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• v.40 no.1
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• pp.25-35
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• 2015

We analyzed the differential effects of histopathology, apoptosis and expression of radiation response genes after chronic low dose rate (LDR) and acute high dose rate (HDR) radiation exposure in spleen, lung and liver of rats. Female 6-week-old Sprague-Dawley rats were used. For chronic low-dose whole body irradiation, rats were maintained for 14 days in a $^{60}Co$ gamma ray irradiated room and received a cumulative dose of 2 Gy or 5 Gy. Rats in the acute whole body exposure group were exposed to an equal dose of radiation delivered as a single pulse ($^{137}Cs$-gamma). At 24 hours after exposure, spleen, lung and liver tissues were extracted for histopathologic examination, western blotting and RT-PCR analysis. 1. The spleen showed the most dramatic differential response to acute and chronic exposure, with the induction of substantial tissue damage by HDR but not by LDR radiation. Effects of LDR radiation on the lung were only apparent at the higher dose (5 Gy), but not at lower dose (2 Gy). In the liver, HDR and LDR exposure induced a similar damage response at both doses. RT-PCR analysis identified cyclin G1 as a LDR-responsive gene in the spleen of rats exposed to 2 Gy and 5 Gy gamma radiation and in the lung of animals irradiated with 5 Gy. 2. The effects of LDR radiation differed among lung, liver, and spleen tissues. The spleen showed the greatest differential effect between HDR and LDR. The response to LDR radiation may involve expression of cyclin G1.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.407-415
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• 2009

The change of the nitrogen-related centers and the color change of electron beam irradiated type Ia natural diamonds were studied. The irradiation of diamond with high-energy electron beam creates lattice defects which are neutral single vacancy $V^0$. It increased with increasing electron dose density. The B aggregation seems to produce vacancies more easily than the A aggregation, because diamonds with more B aggregation have more platelets, which are sufficient breakable size by electron beam. Greenish blue color of irradiated diamond is changed to darker with increasing electron dose density. GR1 centers with a zero-phonon line at 741 nm and phonon sidebands make transmit visible light at 530 nm and it moves to 500 nm with higher intensity of GR1 centers.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.496-501
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• 1995

Experiments were carried out to find out the optimal condition of SCP produced by Cellulomonas sp. KL-6 and to evaluate nutritional value for the protein of this organism Intracellular- and extracellular proteins produced by this strain were estimated to be nearly maximum, $266\;{\mu}g/m{\ell}\;and\;37\;{\mu}g/m{\ell}$, in the medium containing 0.001% of thiamin after 5 days cultivation. When used rice straw as carbon source for the cell growth of this organism after crusing them by cutting mill, and treating them with 1.0% of NaOH and 10.0% of $NH_4OH\;at\;80^{\circ}C$ for 30 minutes and neutralizing continuatively them with 85% of $H_3PO_4$, SCP production rates were very increased to $1.63\;g/{\ell}$ (NaOH) and $1.47\;g/{\ell}$ (NH4OH), respectively than $0.5\;g/{\ell}$ produced in untreated rice straw. We compared their amino acids patterns with that of FAO provisional patterns. Amino acids content of strain KL-6 was excellents. However. when intended these cell mass to use in practical animal feeding test it would be advisable that destruction or lysis of cell wall should be done.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.718-722
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• 2008

Elaeocarpus sylvestris var. ellipticus (E.S.), which contains 1, 2, 3, 4, 6-penta-O-galloyl-beta-D-glucose (PGG), is reported to have the ability to scavenge oxygen radicals, thereby protecting rat neuronal cells from oxidative damage. The potential of an E.S. extract, which contains a rich PGG, to protect radiosensitive lymphocytes and intestinal crypt cells from radiation injury induced by a single whole-body irradiation (WBI) in vivo was investigated. Our results demonstrated that in immune cells, E.S. treatment decreased the percent of tail DNA, a parameter of DNA damage, compared with levels in untreated, irradiated controls. Furthermore, apoptosis was significantly decreased in lymphocytes and intestinal crypt cells of E.S.-treated mice compared with irradiated controls. These results suggest that the E.S. extract can strengthen the radioresistance of radiosensitive lymphocytes and crypt cells by preventing apoptosis. Therefore, it was concluded that E.S. extract has the radioprotective effects in vivo through an inhibition of apoptosis.

• Journal of Korean Neurosurgical Society
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• v.38 no.3
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• pp.184-189
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• 2005

Objective : Hemangioblastomas are highly vascular and benign neoplasm of the central nervous system[CNS]. They can often be found as multiple lesions, as is commonly observed in von Hippel-Lindau[VHL] disease. The aim of this study is to determine the proper management for multiple hemangioblastomas. Methods : Since 1990, 78cases of hemangioblastoma have been encountered. Among these, 9cases were multiple hemangioblastomas that were treated with surgical resection with or without radiosurgery. The medical, radiological, surgical and histological records were reviewed retrospectively and analyzed statistically. Results : Nine patients presented with multiple hemangioblastomas and were diagnosed as VHL disease. The mean follow-up duration was 75.7months [$6.6{\sim}159.2months$] after the first surgical treatment. Three patients were treated with surgical resection alone and six patients were treated by both surgical resection and radiosurgery. Twenty-one surgical procedures [13 surgical resections and 8 radiosurgery] were performed. One patient required ventriculoperitoneal shunt and a posterior fossa decompressive craniectomy because of post-radiation brain swelling. Another patient refused additional treatment for the newly developed lesions after the successful treatment of initial lesions. The other patient who presented with numerous lesions in the whole brain and spine underwent cranio-spinal irradiation. Remaining patients showed good results. Conclusion : The surgical outcomes for the patients with a single lesion of the CNS hemangioblastoma are favorable. However. the treatment of multiple hemangioblastoma is more difficult, and should be treated by surgical resection and radiosurgery with careful consideration.

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.867-874
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• 2000

Two new azobenzene crown ether calix[4]arenes, 10 and 11, were synthesized by two pathways. In the first pathway,two ethoxy nitrobenzene groups were attached to t-butylcalix[4]arenes in a 1,3 position. Subsequent reduction ofthe nitrobenzene group s by metallic zinc in an alkaline solution afforded 10 and 11 in8% and 12%,respectively. In the second pathway,an azobenzene containing two glycolic units was prepared prior connect-ing to t-butylcalix[4]arenes. The yields from the second approach (5%, 8% for 10 and 11, respectively) were lower than those from the former approach. Single crystals of 10 suitable for X-ray crystallography was ob-tained by recrystallization in methanol.Both the X-ray structure and the 1H-NMR spectrum of 10 indicated that the stereoisomer of the azobenzene moiety was trans and the calixarene platform was in cone conformation. 1H NMR spectroscopy suggested that 10 underwent an observable cis-trans isomerization in CDCl3 under room light and upon UV irradiation with cis:trans ratios of 33:67 and 36:64,respectively. Compound 6 which was the precursor of 11showed fluxional behavior and was found to have mixed conformations ofcone and partial cone with a ratio of 47:53 at -30 $^{\circ}C.$ 1H NMR spectrum of 11 suggested that 11 was initially isolated as cis azobenzene with calix[4]arene in cone conformation and underwent conformational interconversion through calix[4]arene annulas in a similar fashion to 6 upon exposing to light. The complexation studies of 10 with picrate salts of Na+ and K+ using 1H NMR spectroscopysuggested that Na+ preferred to bind the cis form of 10 while K+ preferred to bind the trans form. The stereoisomer of the azobenzene unit in 11 changed partially from cis to trans upon complexing with K+.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.221-227
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• 2021

Recently, interests in mask-type skin care devices using light-emitting diodes have been increasing and optical stimuli at certain wavelengths have been known to have various therapeutic effects, such as skin whitening, acne treatment, elasticity and wrinkle improvement by controlling the exposure to wavelengths of light and irradiation time. In particular, light sources of different wavelengths are applied in masks for the purpose of suppressing skin aging, inducing cell proliferation, and alleviating skin inflammation. In this paper, we developed a light-emitting diode control system that is actively used in skin regeneration masks using a microcontroller. Optical stimuli with different manners were applied to skin fibroblast cells in a single or complex wavelengths, and then confirmed how they are effective in the cell differentiation. In addition, we found a specific wavelength that has a positive effect on cell proliferation rates, and confirm the effectiveness of cell proliferation by image processing based quantitative analysis.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.190-198
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• 2001

Purpose : It was reported that Captopril (angiotensin converting enzyme inhibitor) had an effect to reduce the pneumonitis and pulmonary fibrosis induced by radiation in rat. We peformed this study to investigate the radioprotective effect and mechanism of Captopril. Methods and Materials : The comparison was made between the radiation only group and the combined Captopril and radiation group by examining histopathologic findings and immunohistochemical stains $(TNF\alpha\;and\;TGF\beta1)$ at 2 and 8 weeks after irradiation. Each group has 8 to 10 rats (Sprague-Dawley). 12.5 Gy of X-ray was irradiated to the left hemithorax in a single fraction. Captopril (50 mg/kg/d) mixed with water was given per oral and continuously from 1 week prior to irradiation up to 8th week of the experiment. Result : In the combined Captopril and radiation group, the histopathologic changes which were hemorrhage into alveolar space, changes of alveolar epithelium, bronchial epithelium and blood vessels, and perivascular edema were less severe than in the radisation only group at 2 weeks. At 8 weeks, the alveolar epithelial changes and perivascular edema were less prominant in the combined Captopril and radiation group. At 2 weeks, the $TNF\alpha$ expression of the combined Captopril and radiation group was markedly decreased at the alveolar epithelium (p<0.01), lymphoid tissue (p=0.06) and the macrophage of alveolar space (p<0.01) compared with the radiation only group. Furthermore the $TGF\beta1$ expression was significantly prominant at the alveolar epithelium (p<0.02) and the macrophage in alveolar space (p<0.02). At 8 weeks, the expression of $TNF\alpha\;and\;TGF\beta1$ of most sites, except $TGF\beta1$ of the macrophage of alveolar space (p=0.09), showed no significant difference between 2 groups. Conclusion : This study revealed that early lung damage induced by irradiation was reduced with the addition of Captopril in the latent and early pneumonitis phase. The expression of $TNF\alpha\;and\;TGF\beta1$ at 2 weeks and $TGF\beta1$ at 8 weeks was further decreased in the combined Captopril and radiation group than the radiation only group. From these results, it may be concluded that the proinflammatoy cytokine $(TNF\alpha)$ and fibrogenic cytokine $(TGF\beta1)$ probably play the role of the radioprotective mechanism in Captopril.

• Radiation Oncology Journal
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• v.10 no.1
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• pp.7-14
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• 1992

Between August 1988 and December 1991, 24 patients with intracranial tumors were treated with stereotactic radiosurgery(RS) using a 10 MV linear accelerator at Severance Hospital, Yonsei University College of Medicine. There were 5 meningiomas, 3 craniopharyngiomas, 9 glial tumors, 2 solitary metastases, 2 acoustic neurinomas, 2 pineal tumors, and 1 non-Hodgkin's lymphoma. Ten patients were treated as primary treatment after diagnosis with stereotactic biopsy or neuroimaging study. Nine patients underwent RS for post-op. residual tumors and three patients as a salvage treatment for recurrence after external irradiation. Two patients received RS as a boost followed by fractionated conventional radiotherapy. Among sixteen patients who were followed more than 6 months with neuroimage, seven patients (2 meningiomas, 4 benign glial tumors, one non-Hodgkin's lymphoma) showed complete response on neuroimage after RS and nine patients showed decreased tumor size. There was no acute treatment related side reaction. Late complications include three patients with symptomatic peritumoral brain edema and one craniopharyngioma with optic chiasmal injury. Through this early experience, we conclude that stereotactically directed single high doses of irradiation to the small intracranial tumors is effective for tumor control. However, in order to define the role of radiosurgery in the management of intracraniai tumors, we should get the long-term results available to demonstrate the benefits versus potential complications of this therapeutic modality.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.367-375
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• 1998

Purpose : Xerostomia is a complication met by almost all patients who have radiotherapy for cancers of head and neck. Many studies for prevention of xerostomia will be necessary. Radiation-induced acute response of salivary glands has been defined as interphase death or apoptosis. Increased intracellular calcium level have an important role in radiation-induced apoptosis. Calcium channel blocker may prevent radiation-induced apoptosis of salivary glands. This study was designed to evaluate the effectiveness of diltiazem known as calcium channel blocker and pentoxifylline with inhibition of inflammatory response on the apoptosis as an acute response of radiation in rat salivary glands. Materials and Methods : Sprague-Dawley rats with about body weight 200-250 g were divided into 5 study groups : control, radiation alone, diltiazem with radiation, pentoxifylline with radiation, and diltiazem and pentoxifylline with radiation. The diltiazen and pentoxifylline were injected intraperitoneally 20 mg/kg and 50 mg/kg, 30 and 20 mimute before irradiation. respectively. Irradiation was given with a 4 MV linear accelerator. The 1600 cGy of radiation was delivered in a single fraction through a single anterior portal encompassing the entire neck. After 24 h of irradiation, rats were sacrificed and parotid and submandibular glands were removed and stained with hematoxylin and eosin. The quantification of apoptosis was performed by microscopic examination of stained tissue sections at a magnification of 200X and the percentage of apoptotic cell was calculated. Results : On parotid glands, the percentage of apoptosis by radiation alone, diltiazem with radiation, pentoxifylline with radiation, and diltiazem and pentoxifylline with radiation were 1.72$\%$ (8.35/486), 0.64$\%$ (2.9/453), 0.23$\%$ (1.2/516), and 0.28$\%$ (1.1/399), respectively. The apoptosis was markedly reduced in the groups receiving drugs compared with groups receivinge, radiation alone (p<0.05). In serous cell of submandibular glands, the percentages of apoptosis of radiation alone, diltiazem with radiation, pentoxifylline with radiation, and diltiazem and pentoxifylline with radiation were 1.94$\%$ (l1/567), 0.34$\%$ (1.9/554), 0.28$\%$ (1.8/637), and 0.22$\%$ (1.3/601), respectively. In the mucus cell of submandibular glands, the percentages of apoptosis were 0.92$\%$ (5.1/552), 0.41$\%$ (2.5/612), 0.29$\%$ (1.3/455), and 0.18$\%$ (1.0/562), respectively. The apoptosis was markedly reduced in the serous glands (p<0.05), but there was no difference in development of apoptosis in each group of mucus gland. Conclusion : These results suggest that radiation-induced apoptosis of serous cells of salivary glands may be decreased by diltiazem and pentoxifylline administration.