• Toxicological Research
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• v.33 no.2
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• pp.141-147
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• 2017

Peripheral ameloblastic odontoma is a rare variant of odontogenic tumor occurring in the extraosseous region. The present report describes a spontaneous tumor in male Sprague-Dawley (SD) rats. The clinically confirmed nodule in the right mandibular region was first observed when the rat was 42 weeks and remained until the terminal sacrifice date when the animal was 48 weeks of age. At necropsy, a well demarcated nodule, approximately $2.5{\times}2.0{\times}2.0cm$, protruded from the ventral area of the right mandible. The nodule was not attached to mandibular bone and was not continuous with the normal teeth. Histopathologically, the tumor was characterized by the simultaneous occurrence of an ameloblastomatous component and composite odontoma-like elements within the same tumor. The epithelial portion formed islands or cords resembling the follicle or plexiform pattern typical of ameloblastoma and was surrounded by mesenchymal tissue. Formation of eosinophilic and basophilic hard tissue matrix (dentin and enamel) resembling odontoma was observed in the center of the tumor. Mitotic figures were rare, and areas of cystic degeneration were present. Immunohistochemically, the epithelial component was positive for cytokeratin AE1/AE3 (CK AE1/AE3), and the mesenchymal component and odontoblast-like cells were positive for vimentin, in the same manner as in normal teeth. On the basis of these findings, the tumor was diagnosed as a peripheral ameloblastic odontoma in an extraosseous mandibular region in a SD rat. In the present study, we report the uncommon spontaneous peripheral ameloblastic odontoma in the SD rat. We also discuss here the morphological characteristics, origin, histochemical, and immunohistochemical features for the diagnosis of this tumor.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.1
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• pp.171-191
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• 1998

The present study was designed to elucidate the effects of the Co-60 γ irradiation and/or calcium-deficient diet on the periodontal tissue formation in rat pups. The pregnant three-week old Sprague-Dawley rats were used for the study. The experimental group was divided into two groups, irradiation/normal diet group (Group 2) and irradiation/calcium-deficient diet group (Group 3). The control group was non-irradiation/normal diet group (Group 1). The abdomen of the rats at the 19th day of pregnancy were irradiated with single absorbed dose of 350 cGy. The rat pups were sacrificed on the 14th day after delivery, and the maxillae including molar tooth germ were taken. The specimens including the 1st molar tooth germ were prepared to make tissue sections for light and transmission electron microscopy. Some of tissue sections for light microscopy were stained immunohistochemically with anti-fibronectin and anti-osteonectin antibodies. The results were as follows; 1. In the periodontal ligament forming area, the fibroblasts of Group Z showed irregular arrangement and low activity. The immunoreactivity between the fibroblasts and collagen fibers was decreased, compared with Group 1. The fibroblasts of Group 3 showed atrophic change and clumped nucleus. The collagen fibers showed cystic change and low immunoreactivity to the fibronectin. 2. In the cementum forming area, the cementoblasts of Group 2 showed decrease of number and atrophic change. The cementoblasts of Group 3 showed edematous change, atrophy of cytoplasm, and clumping of nucleus. 3. In the alveolar bone forming area, the bone of Group 2 was thin and various degree of immunoreactivity to the osteonectin. Group 3 showed edematous osteoblasts, fibrous degeneration of bone marrow, and weak immunoreactivity to the osteonectin.

• Korean Journal of Head & Neck Oncology
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• v.38 no.1
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• pp.37-41
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• 2022

Sebaceous carcinoma is extremely rare in the parotid gland. Recently, we experienced a case of carcinoma with sebaceous differentiation arising from the parotid gland in patient who was diagnosed as parotid adenoma carcinoma and underwent total parotidectomy. A 73-year-old male visited our department for the evaluation of 3-month history of infra-auricular mass combined with pain. Radiologic finding showed lobulated enhancing and solid mass with calcification in the right parotid gland. Initially, total parotidectomy with supraomohyoid neck dissection was performed. Pathological findings showed capsulated whitish mass with hemorrhage and cystic degeneration. Immunohistochemically, CK7, CK5/6, p63 were positive and CEA was negative. The intra-operative frozen section diagnosis was mucoepidermoid carcinoma. The permanent diagnosis was changed to adenocarcinoma, NOS(not otherwise specified). Fourteen months later, the newly developed mass was noticed on the operation bed. The mass was clinically diagnosed as recurred adenocarcinoma. Revision parotidectomy was performed and pathological findings revealed that the tumor was newly developed sebaceous carcinoma. We report a case of carcinoma with sebaceous differentiation in parotid gland with a review of literature.

• Applied Microscopy
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• v.27 no.4
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• pp.433-452
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• 1997

Mongolian gerbil (Meriones unguiculatus) has been as an animal model for studing the neurological diseases such as stroke and epilepsy because of the congenital incompleteries in Willis circle, as well as the investigation of water metabolism because of the long time-survival in the condition of water-deprived desert condition, compared with other species animals. In order to accomplish the this research, first of all another divided the laboratory animals 5 groups of which each group include the 5 animals. In this study were investigated the histological structure in the kidney, measured the plasma osmolalities at the time of sacrifice of indivisual animals, and the body weights every day during water-deprived. The results obtained in this study were summarized as followings: 1. The body weights and decreasing rates of the body weight in water-deprived mongolian gerbil groups were continuosly decreased. 2. The plasma osmolalities were increased from the 5th water-deprived day, after then the gradually increasing reached nearly its equilibrium state at the 10th water-deprived day. 3. The urine volumes were abruptly decreased from the 2th water-deprived day, after then the gradually decreasing patterns were reached nearly its equilibrium state at the 10th day, and stopped the 11th day. 4. In the light microscopical observation of the kidney, glomerular capillary loop thickening, mesangial matrix increasing, sclerosis, glomerular cystic atrophy, interstitial fibrosis, tubular dilatation, mononuclear interstitial inflammation, interstitial mineralization, and hyperplasia of the collecting duct epithelium in the cortex area, were observed from the 10th water deprived day, and the lesions were gradually severe changed as the time lapse. 5. In the electron microscopical findings of the kidney, the degenerative changes of endothelial cell, podocyte and mesangial cell in glomeruli were initially observed on the 10th water-deprived day as well as the degeneration of microvilli and intracellular organelle in the renal tubules.

• The Korean Journal of Nuclear Medicine
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• v.16 no.1
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• pp.41-48
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• 1982

113 patients with nodular goiter were studied cytologically by needle aspiration for differential diagnosis at the department of internal medicine, Chung Nam National University Hospital since October 1980 till July 1981, and the final diagnosis taken from biopsies were compared with the cytologic method on the 44 cases who received operation. The results were obtained as follows: 1. Among the 113 cases of total patients, male were 15 cases (13.3%) and female were 98 cases (86.7%) and the sex ratio (M:F) was 1 : 6.5. The peak age incidence was in the third decade followed by forth and second decades. 2. The findings of cytological diagnosis in 113 cases showed benign adenoma in 69 cases (61.1 %), Subacute and chronic thyroiditis in 22 cases(19.5%), papillary carcinoma in 15 cases (13.3%) and follicular carcinoma in 7 cases (6.2%), respectively, and 48 cases (69.6%) of the.adenomas and 2 cases(9.1%) of papillary carcinomas showed combined cystic degeneration of the nodules. 3. The diameter of the nodules by palpation revealed within $2\sim5cm$ in 88 cases (77.9%) out of 113 cases, below 2 cm in 17 cases and over 5cm in 8 cases and there were no significant relationship between the size of the nodule and disease entity. 4. The findings of thyroid scintigram using $^{131}I$ in 113 cases of nodular goiter showed "cold nodule" in 111 cases (98.2%) and normal scan (radioactivity) in 2 cases (1.8%) which showed adenoma in cytology and there was no cases with "hot nodule". 5. The thyroid functions of the 113 cases revealed as euthyroidism in 108 cases (95. 6%), hypothyroidism in 2 cases (1.8%) who showed chronic thyroiditis and hyperthyroidism in 3 cases (2.7%) in adenomas but there was no evidence that the nodules of the above 3 cases were the reason of hyperthyroidism. 6. In 44 operated cases, the histological diagnosis revealed 23 cases of adenoma out of 27 cases(85.2%) who were diagnosed as adenoma by cytology and 15 cases of malignancy out of 17 cases (88.2 %), and the overall diagnostic accuracy of aspiration cytology was 86.4 %.

• The Journal of the Korean bone and joint tumor society
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• v.9 no.2
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• pp.148-154
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• 2003

Purpose: To correlate the significant MRI findings and histologic features of the Schwannoma of the extremities and to review the clinical characteristic and the result of the surgical enucleation. Materials and Methods: 67 patients with pathologically proven Schwannoma of the extremities, who were surgically treated at our institutes between January 1996 and June 2002, were selected for this study. The clinical records, EMG, MRI and histologic findings were reviewed. Age of the patients ranged from 8 to 75 years with average of 44.7 years. Mean follow-up period was 9.7 months with raging from 3 months to 46 months. Results: On MRI, Schwannoma shows a well-demarcated fusiform mass with a low to intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images, which is connected to parent nerve. A target pattern with peripheral hyperintensive rim and central low intensity on T2-weighted images was seen in 6 cases (15%), and fasciculation pattern with inhomogenous intensity in the hyperintensity on T2-weighted images was observed in 24 cases (62%). Various degree of cystic degeneration was discovered in 25 cases (64%). Postoperative complications include tingling sense or radiating pain in 5 patients, paresthesia in 2 patients, nerve palsy in 2 patients, but all of the complications were recovered during followup period. There were no local recurrence or malignant change. Conclusion: MRI demonstrates characteristic findings of Schwannoma, and very useful tool for preoperative diagnosis and planning of surgery. Exact preoperative diagnosis and meticulous enucleation are enough option of treatment.

• Journal of Veterinary Clinics
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• v.11 no.1
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• pp.485-505
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• 1994

Lead toxicity was evaluated in forty-five cats on a balanced diet, treated with 0(control), 10, 100(low), 1, 000, 2, 000 and 4, 000(high)ppm of lead acetate orally on a body weight basis. The objectives were to describe the gross and histopathologic changes and to demonstrate what tissue lead concentrations correlate with the known dosages of lead. In subclinical lead toxicity, greater than 80% of the absorbed lead was deposited in the bone, whereas in more acute lead toxicity, 42% of absorbed lead was deposited in the bone and 36% and 20% of absorbed lead was deposited in the kidneys and in the liver, respectively. No gross lesions were found in the nervous system. Yellow-brown colored livers appear to be associated with lead toxicity. Neuronal necrosis in the cerebrum was the most predominant histopathologic finding. Astrocytic proliferation in the cerebral gray matter was observed in 1 high dose cat. Gliosis was noted in the cerebral cortex of 6 high dose cats. Two high dose cats had demyelination in the deepest layer of the cortical gray matter of the cerebrum. Extravasation of red cells and cavitation around the vessels were found in the cerebrum of 1 high dose cat. Six high dose cats had degeneration of Purkinje cells in the cerebellum. The microscopic findings in the peripheral nerves were ambiguous. In more acute toxicity, the cats had lead inclusions in the epithelial cells of proximal tubules of the kidneys of 7 cats and hepatocytes of the liver of S cats. These inclusions could be seen wlth H&E, but were more prominent with orcein staining. Two high dose cats had granulomas and connective tissue hyperplasia between tubules of the kidneys. Periportal hepatocyte vacuolization was observed in the liver of 22 cats. Vacuolization of seminiferous tubules and a reduced number of spermatogonia(indicative of reduced spermatogenesis) were found in the testis of 5 treated cats. Cystic ovaries were observed in 3 high dose cats and poor development of oogonia was found in 2 cats. The diagnosis of lead toxicity in cats can be suspected on the basis of the histopathologic lesions described, and can be of value in contributing to a diagnosis. A reliable diagnosis of lead poisoning can be helped utilizing tissue lead analysis(post molten)