Radiation effect on the stages of amelogenesis in the rat incisor

학위논문(박사)--서울대학교 대학원 :치의학과 구강악안면방사선학전공,1997.Docto

RADIATION EFFECT ON THE STAGES OF AMELOGENESIS IN THE RAT INCISOR

The purpose of this study was to investigate the radiation effect on the stages of amelogenesis. Twenty ll-day-old rats which were irradiated by 4Gy of garmna radiation on the 19th prenatal day were used for the experimental group and twenty ll-day-old rats which were not irradiated were used for the control group. The length of each zone of amelogenesis were measured on the sagittal section using a light microscopic enlargement at 400 x the normal view while the morphologic changes of ameloblasts of each zone were observed electron­microscopically. The obtained results were as followed : 1. The length of the region of facing pulp and facing dentin of the zone of presecretion were increased by 11.5％(P0.05). 4. Electron-microscopically, enlargement of the cell membrane, rER, mitochondria, and nuclear membrane were observed. These changes were mostly severe in the zone of maturation.본 연구 논문은 1995년도 서울대학교병원 지정진료공동연구비 지원에 의한 것임

Squamous cell carcinoma in the submandibular space

A 66-year-old man visited author's institute complaining of the swelling on the submandibular gland area. Clinically, the exophytic mass penetrated the skin of the submandibular area. On MRI, the lesion occupied the left submandibular space and extended downward, protruding exterior to the subcutaneous fat layer, but the center of the lesion was located on the side of the skin and the growth exterior to the skin was prominent. Demarcation of the lesion and the submandibular gland was unclear. Histopathologically the epithelial nests and keratin production were seen, then the biopsy result was squamous cell carcinoma. The stroma of lesion showed a myxoid characteristic and some ducts showed metaplasia of the ductal cells, which suggested the gland-origin carcinoma. However, lots of keratin production and carcinomatous change of cells continuous to the normal epithelium of the skin, the skin-origin carcinoma invading into the submandibular gland area could not be excluded

Recurrent odontogenic keratocyst within the masticatory space

The odontogenic keratocyst (OKC) is a developmental odontogenic cyst typically occurring in the jaws. Since the first description of OKC was published in 1956, the lesion has been of particular interest because of its specific histopathologic features, high recurrence rate, and aggressive behavior. Recurrences most commonly arise within bone at the site of the original cyst. However, as lining cells may find their way into surrounding tissues either from implantation during surgery or from cortical perforation recurrences may arise at a distance from the original cyst. Here, we report a rare case of recurrent OKC which was first developed in mandible and recurred within the masticatory space

The effect of retinoic acid on radiosensitivity analyzed by linear-quadratic model and apoptosis in head and neck squamous carcinoma cell lines

Purpose : To evaluate the effect of all-trans-retinoic acid on radiosensitivity and radiation-induced apoptosis in NHOK, HEp-2 and FaDu cell lines. Material and Methods: We measured the changes in survival fraction at 2 Gy (SF2), α and β after treatment of retinoic acid (1μM) prior to irradiation with doses of 2, 4, 6 and 10 Gy and correlated the radiosensitizing effect of retinoic acid with them. Also, apoptosis induction was assayed with the flow cytometry on days 1,2, 3, 4 and 5 after irradiation (2, 10 and 20 Gy) combined with retinoic acid. Results and Conclusion: SF2 values for NHOK, HEp-2 and FaDu cell lines were 0.54, 0.64 and 0.41, respectively and the cell line of FaDu was the most radiosensitive. For cell lines of NHOK and HEp-2, pretreatment of cells with retinoic acid resulted in a significant decrease of the SF2 values. The α/β ratios of x-ray survival curve were 8.714 (NHOK), 4.098 (HEp-2) and 11.79 (FaDu). The α/β ratio for NHOK decreased on pretreatment with retinoic acid, whereas those for HEp-2 and FaDu increased. Radiation induced apoptosis in all cell lines but, retinoic acid did not affect the apoptosis