• Imaging Science in Dentistry
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• v.36 no.1
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• pp.33-40
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• 2006

Purpose : To investigate clusterin expression in the acini and ductal cells of rat submandibular glands after Co-60 gamma irradiation. Materials and Methods : The male Sprague-Dawley rats weighing approximately 250 gm were divided into control and experimental groups. The experimental group was irradiated with a single absorbed dose of 2, 5, 10, and 15 Gy on the head and neck region. All the rats were sacrificed at 1, 3, 7, 14, 21, and 28 days after irradiation. The specimens including the submandibular gland were sectioned and observed using a immunohistochemical method. Results : In the 2 Gy group, clusterin expression was similar to that of the control group at 1 day after irradiation and it was observed in the striated ductal cells at 3 days after irradiation. In the 5 Gy group, clusterin expression was observed in the striated ductal cells at 1 day after irradiation and gradually increased in the 10 and 15 Gy groups. In the 15 Gy group, clusterin expression was prominent in the striated ductal cells at 1 day after irradiation, but it gradually decreased with the experimental period. The destruction of the striated ductal cells was observed in the 2 Gy group at 21 days after irradiation and in the 5, 10, and 15 Gy groups at 7 days after irradiation. The destruction of the acinar cells was observed in the 2 Gy group at 28 days after irradiation and in the 5, 10, and 15 Gy groups at 14 days after irradiation. Conclusion : Clusterin expression was induced by low doses of irradiation and it appeared to be involved in the regulation of cellular response to irradiation.

• Imaging Science in Dentistry
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• v.35 no.3
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• pp.133-139
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• 2005

Purpose To observe the histopathological changes in the periodontal tissues of mandibular molars in streptozotocin-induced diabetic rats after irradiation. Materials and Methods : The male Sprague-Dawley rats weighing approximately 250 gm were divided into four groups: control, diabetes, irradiation, and diabetes- irradiation groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in the control and irradiation groups were injected with citrate buffer only After 5days, the head and neck region of the rats in irradiation and diabetes-irradiation groups were irradiated with a single absorbed dose of 10Gy. All the rats were sacrificed at 3, 7, 14, 21, and 28 days after irradiation. The specimen including the mandibular molars were sectioned and observed using a histopathological method. Results In the diabetes group, osteoclastic activity was observed in the alveolar bone and the root throughout the period of experiment. Also, osteoblastic and fibroblastic activities were markedly decreased. In the irradiation group, the osteoclasts were observed in the alveolar bone and the dilated capillaries were increased in the early experimental phases. However, vigorous osteoblastic activity was noted in the late experimental phases. In the diabetes-irradiation group, osteoblastic activity in the alveolar bone and the root was observed in the early experimental phases. However, there were no resorption and osteoblastic activity in the alveolar bone and the root in the late experimental phases, and obvious atrophic change of fibrous tissues was noted. Conclusion : This experiment suggests that osteoblastic activity was caused by irradiation in the late experimental phases, but atrophic change of the periodontal ligament tissues was induced after irradiation in diabetic state.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1233-1239
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• 2014

Background: The incidence of brain metastases (BM) varies in patients with non-small cell lung cancer (NSCLC), calls into question the value of prophylactic cranial irradiation (PCI). It is possible that clinicopathologic characteristics are associated with the development of BM, but these have yet to be identified in detail. Thus, we conducted the present meta-analysis on risk factors for BM and the value of PCI in patients with NSCLC. Methods: Eligible data were extracted and the risk factors for BM and the value of PCI in patients with NSCLC were analyzed by calculating the pooled odds ratio (OR). Heterogeneity was detected using Q and I-squared statistics, and publication bias was tested by funnel plots and Egger's test. Results: Six randomized controlled trials with a focus on the value of PCI and 13 eligible studies with a focus on risk factors for BM were included. PCI significantly reduced the incidence of BM in patients with NSCLC (p=0.000, pooled OR=0.34, 95% confidence interval = 0.37-0.59). Compared with non-squamous cell carcinoma, squamous cell carcinoma was associated with a low incidence of BM in patients with NSCLC (p=0.000, pooled OR=0.47, 95% confidence interval =0.34-0.65). The funnel plot and Egger's test suggested that there was no publication bias in the current meta-analysis. Conclusions: This meta-analysis provides statistical evidence that compared with non-squamous cell carcinoma, squamous cell carcinoma can be used as a predictor for BM in patients with NSCLC, and PCI might reduce the incidence of BM in patients with NSCLC, but does not provide a survival benefit.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.269-277
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• 1989

CNS prophylaxis with 18 or 24 Gy cranial irradiation plus intrathecal methotrexate was given to 134 childhood acute lymphoblastic leukemia patients who had got bone marrow remission (M1) after remission induction chemotherapy from August 1979 to December 1986. The rate of initial total CNS relapse was 14.2% (19/134), the rate of isolated CNS relapse was 5.2% (7/134), and the rate of CNS relapse concomittantly combined with bone marrow relapse or testicular relapse was 9% (12/134). Male sex or older age was accociated with higher CNS relapes and the initial peripheral leukocyte count over 50,000/ul had higher relapse rate. Relapse with radiation dose of 18Gy was somewhat lower than that with 24Gy. Within 4 years after CNS prophylaxis occurred 89% of the total CNS relapses, 100% of the isolated CNS relapses, and 83% of the combined CNS relapses. Adjusted to exposed cases to risk of CNS relapse, the total CNS relapse rate was 11.9% during maintenance chemotherapy and 4.9% after maintenance chemotherapy.

• Imaging Science in Dentistry
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• v.32 no.1
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• pp.1-10
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• 2002

Purpose: To observe the histopathological changes following irradiation on the wound healing after tooth extraction in the rachitic rats. Materials and Methods: In order to carry out this study, the rats were divided into four groups: Group 1 (normal diet/non-irradiation group), Group 2 (normal diet/irradiation group), Group 3 (rachitogenic diet/non-irradiation group), and Group 4 (rachitogenic diet/irradiation group). Rachitic changes were induced with rachitogenic diet No. 2 (high calcium, low phosphorus, and Vitamin D deficient diet) for 5 weeks. After the extraction of both maxillary first molars of the rats in Group 2 and 4, the head and neck of the rats were irradiated with single absorbed dose of 10 Gy. The rats were sacrificed at the 1st, 5th, 10th, and 15th day after tooth extraction. The specimens including the extraction wound were sectioned, stained with the hematoxylin-eosin and Masson's trichrome method and examined under the light microscope. Results: In the Group 2, the amount of newly formed bone trabeculae on the periphery of extraction socket and osteoblastic activity were reduced. In the Group 3, epithelial fusion was not revealed on the 5th day after toothe extraction and growth rate of osteoid formation was reduced. In the Group 4, necrotized tissue at the outer surface of extraction socket and destructive changes on the alveolar bones were noted on the 10th day. Epithelial fusion was not revealed and large amounts of osteoclast were noted on alveolar bone on the 15th day. Conclusion: The healing process of wound after tooth extraction was retarded by irradiation and especially in the rachitic rats.

• Journal of Korean Neurosurgical Society
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• v.37 no.5
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• pp.370-374
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• 2005

Objective: We investigated the morphologic changes within 24 hours after a single ${\gamma}$-irradiation in the rat brain. Methods: Forty Sprague-Dawley rats were used. After a burr hole trephination on right parietal area, cerebral hemisphere was irradiated with 2Gy and 5Gy using iridium-192($^{192}Ir$), respectively. The effect was assessed at 4, 8, 12 and 24 hours after irradiation. The histological changes were scored following the detection of edema or disarray severity. TUNEL-positive cells exhibiting apoptotic morphology were counted in irradiated region. Results: Cortical edema and disarray were initially showed at 4 or 8 hour and almost all defined at 24 hour after irradiation. And the injury was wedge shape. TUNEL-positive cells were minimal at 8 hour after irradiation as the number of positive cells were $2.6{\pm}5.27$(n=5) after 2Gy, and $0.8{\pm}0.84$(n=5) after 5Gy. But, the number of apoptotic cells were increased markedly to $60{\pm}6.24$ at 12 hour after 2Gy and to $104{\pm}19.7$ at 24 hour after 5Gy. Conclusion: There were prominent morphologic changes immediately after ${\gamma}$-irradiation. And, apoptosis was increased according to the time period. These findings implicate that brain irradiation induces rapid apoptotic change, which may play an important role in the pathogenesis of radiation-induced pathologic conditions.

• Toxicological Research
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• v.26 no.3
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• pp.177-183
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• 2010

This study was performed to examine whether elevated activity of cAMP responsive element-binding protein (CREB) attenuates the detrimental effects of acute gamma ($\gamma$)-irradiation on hippocampal neurogenesis and related functions. C57BL/6 male mice were treated with rolipram (1.25 mg/kg, i.p., twice a day for 5 consecutive days) to activate the cAMP/CREB pathway against cranial irradiation (2 Gy), and were euthanized at 24 h post-irradiation. Exposure to $\gamma$-rays decreased both CREB phosphorylation and immunohistochemical markers for neurogenesis, including Ki-67 and doublecortin (DCX), in the hippocampal dentate gyrus (DG). However, the rolipram treatment protected from $\gamma$-irradiation-induced decreases of CREB phosphorylation, and Ki-67 and DCX immunoreactivity in the hippocampal DG. In an object recognition memory test, mice trained 24 h after acute $\gamma$-irradiation (2 Gy) showed significant memory impairment, which was attenuated by rolipram treatment. The results suggest that activation of CREB signaling ameliorates the detrimental effects of acute $\gamma$-irradiation on hippocampal neurogenesis and related functions in adult mice.

• Imaging Science in Dentistry
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• v.34 no.2
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• pp.81-89
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• 2004

Purpose: To investigate the histopathological changes in the temporomandibular joint in streptozotocin-induced diabetic rat following irradiation. Materials and Methods : Sprague-Dawley rats weighing about 250 gm were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in the control group were injected with citrate buffer only. After 5 days, the head and neck region of the rats in diabetic-irradiated group were irradiated with single absorbed dose of 10 Gy. The rats were killed at 1, 3, 7, 14, 21, and 28 days after irradiation. The specimen including the temporomandibular joint were sectioned and observed using a histopathological method. Results : In the diabetic group, severe bone resorption in the mandibular condyle was observed throughout the period of experiment. Necrosis of bone marrow and trabeculae was observed at 28 days after diabetic state. Atrophy and fibrosis in the retrodisca] tissue was gradually progressed during the time of the experiment. In the diabetic-irradiated group, severe bone resorption in the mandibular condyle was observed during the early experimental phases, but regeneration of bone marrow was initiated at ]4 days after diabetic state and irradiation. A]so, calcification of abnormal trabeculae was observed at 28 days after diabetic state and irradiation. The retrodisca] tissue was degenerated in the early experimental phases, but it had been gradually regenerated during the experimental time. Conclusion: This experiment suggests that bone resorption and degeneration in the mandibular condyle are caused by the induction of diabetes, and abnormal bone formation is induced after irradiation in diabetic state.

• Imaging Science in Dentistry
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• v.33 no.3
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• pp.161-169
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• 2003

Purpose: To observe the histologic changes and clusterin expression in the acinar cells of the submandibular gland in streptozotocin-induced diabetic rat following irradiation. Materials and Methods: Mature Sprague-Dawley rats were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced in the Sprague-Dawley rats by injecting streptozotocin, while the control rats were injected with citrate buffer only. After 5 days, rats in diabetic-irradiated group were irradiated with single absorbed dose of 10 Gy to the head and neck region. The rats were killed at 1, 3, 7, 14,21, and 28 days after irradiation. The specimen including the submandibular gland were sectioned and observed using histologic and immunohistochemical methods. Results : Morphologic change of acinar cells was remarkable in the diabetic group, but was not observed in the diabetic-irradiated group. Necrotic tissues were observed in the diabetic-irradiated group. Coloring of toluidine blue stain was most increased at 14 days in the diabetic group, however there were no significant change throughout the period of the experiment in the diabetic-irradiated group. Expression of clusterin was most significant at 14 days in the diabetic group, but gradually decreased with time after 7 days in the diabetic-irradiated group. Degeneration of clusterin was observed in the diabetic-irradiated group. Conclusion : This experiment suggests that the acinar cells of submandibular gland in rats are physiologically apoptosed by the induction of diabetes, but that the apoptosis is inhibited and the acinar cells necrotized after irradiation.

• Imaging Science in Dentistry
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• v.33 no.1
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• pp.5-14
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• 2003

Purpose: To observe the histologic pattern of healing in molar tooth extraction sockets of streptozotocin-induced diabetic rats following irradiation. Materials and Methods: Mature Sprague-Dawley rats were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced by injecting streptozotocin. Control rats were injected with a citrate buffer only. After 5 days, the right maxillary first molar was extracted under general anesthesia from each of the rats. After the extraction, rats in the diabetic-irradiated group were irradiated with a single absorbed dose of 10 Gy to the head and neck region. The rats were killed at 1, 3, 7, 14, 21, and 28 days after treatment. Tissue sections were stained with hematoxylin-eosin and Masson's trichrome. Results: In the diabetic and diabetic-irradiated groups, the early healing process of the socket extraction was similar to the control group, but bone formation was delayed at 7 days after the treatment. In the diabetic-irradiated group, alveolar bone surrounding the extraction socket showed signs of necrosis at 3 days after treatment, and hemorrhage was observed in connective tissue within the extraction socket at 14 days after treatment. Conclusion: This experiment revealed that the healing process of the extraction socket was severely delayed and retarded by irradiation in the diabetic state.