1.A Study on Misclassification Arising from Random Error in Exposure Measurement.
Il SUH ; Chung Mo NAM ; Hyung Gon KANG
Korean Journal of Epidemiology 1996;18(1):108-118
There are many epidemiologic studies to find the relationship between disease occurrence and categorized exposure variables which are measured in continuous scales. Recently, it has been found that the differential misclassification can arise when exposure variables are observed with measurement errors and categorized for the analysis. Even though the differential misclassification leads to serious misclassification bias, there is no theoretical attempt to correct the misclassification bias occuring in these circumstances. In this paper, we propose a new statistical method to reduce the misclassification bias due to dichotomizing continuous exposure variables. Since the exposure values are more likely to be misclassified when the true exposure values are close to the cutoff point, the method proposed here gives smaller weights in these case and more weights when these values are far from cutoff point. Simulation studies are performed to compare the bias and the power of the proposed method compared to other methods. Main results are as follows: 1. The proposed method produces the smaller bias and the higher power than the simple method which modifies misclassified data using sensitivity and specificity of exposure misclassification. 2. When the standard deviation of the measurement error are moderately large, the bias and the power of the proposed estimate are somewhat better than those of the modified estimate which excluding the misclassified observations in the analysis. In conclusion, the method proposed here is found to be useful in epidemiologic studies when continuous exposure variables are obtained with measurement error and categorized in the analysis.
Bias (Epidemiology)
;
Sensitivity and Specificity
;
Weights and Measures
2.Two Cases of Malignant Histiocytosis.
Duck Hyun KIM ; Dong Kun KIM ; Hyung Il KIM ; Soo Il CHUN ; Chung Koo CHO
Korean Journal of Dermatology 1984;22(3):302-309
Two cases of malignant histiocytosis, in which skin involvement was a prominent finding at initial clinical presentation, are reported. 1nteresting histopathologic findings, including Langerhans granule in one case and numerous eosinophils in another, were observed. In one case remission was achieved with BACOP chemotherapy (Bleomycin, Adriamycin, Cyclophosphamide, Vincristine, and Prednisone). In the other case, the patient died nine months after the onset of the disease without any treatment.
Cyclophosphamide
;
Doxorubicin
;
Drug Therapy
;
Eosinophils
;
Histiocytic Sarcoma*
;
Humans
;
Skin
;
Vincristine
3.A case of congenital goiter with congenital hypothyroidism due to organification defect.
Ik Hee LEE ; Sung Yong JUNG ; Thi Hyung PARK ; Sa Jun CHUNG ; Chang Il AHN
Journal of the Korean Pediatric Society 1993;36(7):1002-1008
We experienced a case of congenital goiter with congenital hypothyroidism in 45 day-old male, who complained of respiratory difficulty and anterior neck mass. After admission, he was diagnosed congenital hypothyroidism by the clinical manifestations and laboratory tests including biochemistry, radioimmunoassay, radioisotope study, perchlorate discharge test, and bone radiography. We obtained positive finding at the perchlorate discharge test and found that his congenital goiter with congenital hypothyroidism was manifested by organification defect. We started treatment with L-thyroxine orally at 6th hospital day. The case was presented with brief review of literatures.
Biochemistry
;
Congenital Hypothyroidism*
;
Goiter*
;
Humans
;
Male
;
Neck
;
Radiography
;
Radioimmunoassay
;
Thyroxine
4.Secondary Biliary Cirrhosis in A Case with Intraductal Growth of Hepatocellular Carcinoma.
Hyung Geun SONG ; Yong Il KIM ; Chung Yong KIM ; Soo Tae KIM
Korean Journal of Pathology 1987;21(3):185-191
A case of hepatocellular carcinoma (HCC) complicating with secondary biliary cirrhosis due to intrahepatic bile duct growth of the tumor is presented. The patient was 34 years-old male who had been suffered from right upper quadrant pain with intermittent fluctuating jaundice for 4 months. Left lobectomy specimen contained a single, 4 cm sized, relatively well circumscribed and partly protruding nodular HCC in the medial seqment of left lobe. It compressed the left hepatic duct, and the intra and extra-hepatic ducts were completely plugged with tumor casts (extending to the common bile duct at the operating table). Remaining hepatic parenclyma was the seat of advanced secondary biliary cirrhosis in which were abundance of HBsAg-containing hepatocytes possibily representing a HBsAg carrier status. Biliary cirrhosis in HCC is an extremely rare manifestation, reflecting the delayed adequate clinical procedure by unusual pattern of obstructive jaundice. In such a case presenting as persisting and fluctuating obstructive jaundice in HCC, an intrabile duct tumor growth should be suspected.
Male
;
Humans
;
Carcinoma, Hepatocellular
5.A Study of Relation between Stable Microbubble Rating and Pulmonary Surfactant Concentration in vitro.
Seong Yong JUNG ; Thi Hyung PARK ; Chung Woo BAE ; Chang Il AHN
Journal of the Korean Pediatric Society 1994;37(8):1048-1054
Respiratory distress syndrome (RDS) of preterm infants remains a significant cause of morbidity and mortality despite improvements in neonatal intensive care and artificial ventilatory techniques. After identification of the deficiency of pulmonary surfactant is major pathophysiologic basis in RDS, artificial surfactant replacement therapy in RDS was first successfully tested by Fujiwara and co-workers in 1980. therefore, exogenous surfactant replacement produced exellent results in improved clinical and repiratory status during the acute period and decreased incidence of late complications and mortality. According to comparison of administration timing between early (within 6 hours after birth) and late (after 6 hours)group, early replacement therapy is more effective in improving of clinical course and prognosis. Because of that, early, just after birth, recognition and detection of RDS is also important procedure. There are many investigations and methods for the detection of RDS in prenatal or postnatal period. Among then, stable microbubble rating (SMR) test was a simple method and SMR test has a higher diagnostic accuracy. To determine the relation of the SMR and purified natural surfactant (PNS) concentration in vitro, the author conducted each 5 times test of SMR method according to 5 groups of PNS concentration by using modified Pattle's method. The results were as follows: 1) The mean and standard deviation of SMR according to 5 groups of PNS concentration were 119.4 (15.0in 20mug PL (phospholipid)/ml, 452.2 (160.2 in 40mug PL/ml, 879.0 (93.4 in 60mug PL/ml, 1311.8 (274.8in80mug PL/ml, 1710.6(272.3 in 100mug PL/ml. 2) The regression curve of SMR and PNS concentration showed statistically significant relation(p<0.005). In conclusion, the SMR test was a good method in estimation of surfactant concentration in vitro and also in diagnosis of RDS recognized as a surfactant deficiency. In the future, we expected that prophylactic surfactant replacement therapy. immediate after birth, will be more popular in the field of neonatal care of RDS. So, we recommended the use of this method for early detection and serving optimal care of RDS.
Diagnosis
;
Humans
;
Incidence
;
Infant, Newborn
;
Infant, Premature
;
Intensive Care, Neonatal
;
Microbubbles*
;
Mortality
;
Parturition
;
Prognosis
;
Pulmonary Surfactants*
6.The Use of the Copper Vapor Laser for Vascular Lesion Treatment.
Sang Eun MOON ; Jin Ho CHUNG ; Hyung Don BANG ; Jai Il YOUN
Annals of Dermatology 1996;8(1):14-18
BACKGROUND: While the effect of the flashlamp pumped dye laser in the treatment of telangiectasia and other vascular disease has been reported by many authors, there have been a few reports on the therapeutic effect of the copper vapor laser(CVL) on telangiectasia and other vascular lesions. OBJECTIVE: Our purpose was to assess the clinical results in Korean patients who had cutaneous vascular disorders that were treated with the CVL at 578 nm. METHODS: A total of 23 patients with vascular lesions such as telangiectasia were involved. The effect of the laser treatment was evaluated 3 months after the last treatment. RESULTS: Of the 15 patients with telangiectasia, 12 patients showed good or excellent responses. 2 out of 3 patients with strawberry hemangioma showed good results. As for the other lesions, 2 out of the remaining patients 5 showed excellent results. CONCLUSION: The CVL has a beneficial effect and is a good alternative treatment modality for vascular lesions.
Copper*
;
Hemangioma, Cavernous
;
Humans
;
Lasers, Dye
;
Lasers, Gas*
;
Telangiectasis
;
Vascular Diseases
7.A Case of Successful Colonoscopic Treatment of Acute Appendiceal Bleeding by Endoclips.
Il Hyung CHUNG ; Kwang Hyun KIM
Journal of the Korean Society of Coloproctology 2011;27(6):329-332
Lower gastrointestinal bleeding is a common disease among elderly patients. The common sources of lower gastrointestinal bleeding include vascular disease, Crohn's disease, neoplasm, inflammatory bowel disease, hemorrhoid, and ischemic colitis. However, bleeding from the appendix has been reported very rarely in patients with lower gastrointestinal tract bleeding. In general, after a colonoscopic diagnosis of appendiceal bleeding, a laparoscopic or surgical appendectomy would be recommended. We report a case of successful colonoscopic treatment of appendiceal bleeding without complications by endoclips. This report suggests that colonoscopic clipping is a safe and effective means to treat bleeding from appendiceal lesions. Further study is needed to evaluate procedure-related complications and to confirm the procedure's safety and efficacy.
Aged
;
Appendectomy
;
Appendix
;
Colitis, Ischemic
;
Colonoscopy
;
Crohn Disease
;
Hemorrhage
;
Hemorrhoids
;
Humans
;
Inflammatory Bowel Diseases
;
Lower Gastrointestinal Tract
;
Vascular Diseases
8.A modified elution method for determining the presence of fetal red blood cells.
No Bum LEE ; Hye Kyung LEE ; Jung Hwan SHIN ; Moon Il PARK ; Sung Ro CHUNG ; Hyung MOON
Korean Journal of Perinatology 1992;3(2):72-76
No abstract available.
Erythrocytes*
9.The Calretinin Immunoreactive Ganglion Cell Postsynaptic to the ON-Cholinergic Amacrine Cell in the Guinea Pig.
Hyung Chung KIM ; Wool SUH ; Jung Il MOON ; Kyu Ryong CHOI
Journal of the Korean Ophthalmological Society 2008;49(2):340-351
PURPOSE: To demonstrate the characterization calretinin-immunoreactive displaced amacrine cells in the ganglion cell layer using immunohistochemistry and electron microscopy. METHODS: For immunohistochemistry, sections from guinea pig retina were incubated with mouse monoclonal antibody directed against calretinin. For double label studies, sections were incuated in mixture of mouse monoclonal anti-calretinin or rabbit polyclonal anti-calretinin with following antibodies: goat polyclonal anti-ChAT, rabbit polyclonal anti-GABA, mouse monoclonal anti-GABAA receptor alpha1, beta2/3. Sections were analyzed using Bio-rad Radiance Plus confocal scanning microscope. Stained sections from three guinea pig were observed with transmission electron microscope. RESULTS: Calretinin immunoreactivity was present in displaced amacrine cells and ganglion cells gaving rise to processes ramified in the inner part of the inner plexiform layer in stratum 4. The same stratum was also occupied by the dendrites of ON-cholinergic amacrine cells. Double-labeling demonstrated that dendrites and cell bodies of displaced amacrine cells colocalized with ON-cholinergic amacrine cells and dendrites of ganglion cells directly overlapped with dendrites of ON-cholinergic amacrine cells. The synaptic connectivity was identified by electron microscopy. Ganglion cell dendrites received synaptic input from ON-cholinergic amacrine cell. GABAA receptor beta2/3 subunit bands cofaciculates the dendrites of displaced amacrine cell and ganglion cell that are juxtapose to the alpha1 subunit of GABAA receptor. CONCLUSIONS: These results indicate that ON-cholinergic amacrine cells modulate calretinin-labeled ganglion cell via GABAA receptor beta2/3 in the guinea pig retina.
Amacrine Cells
;
Animals
;
Calcium-Binding Protein, Vitamin D-Dependent
;
Dendrites
;
Electrons
;
Ganglion Cysts
;
Goats
;
Guinea
;
Guinea Pigs
;
Immunohistochemistry
;
Mice
;
Microscopy, Electron
;
Retina
10.Treatment of Congenital Dislocation of the Hip by Closed Reduction
Sung Man ROWE ; Il Sung PARK ; Go Hun CHUNG ; Hyung Soon KIM
The Journal of the Korean Orthopaedic Association 1990;25(3):806-811
The closed reduction has made an important contribution to the treatment of children under the age of 24 months. The authors report a clinical experience of 20 patients(21 hips) with congenital dislocation of hip who were treated by closed reduction at the department of Orthopaedic Surgery of Chonnam University Hospital. There were total 230 patients(237 hips) disgnosed as having congenital dislocated hip for 10 years from 1978 to 1987 and 20 patients of them were included in this study. The follow-up period ranged from 1 year to 10 years with an average 3 years. The results are as follows: l. All but one were girls, comprising 19 (20 hips) of 20 patients. 2. The age at closed reduction were under 6 months in 2, 7 to 12 months in 4, 13 to 18 months in 10 and 19 to 24 months in 4. 3. Of the 21 hips treated by closed reduction, 17 hips achieved a satisfactory result(81%). The other four hips had redislocation(2 hips) and subluxation(2 hips). 4. Four additional treatments were open reduction in 3 and Salter innominate osteotomy in l. 5. The acetabular and center-edge angle improved from the averge 36.1 and
Acetabulum
;
Child
;
Dislocations
;
Female
;
Follow-Up Studies
;
Hip
;
Humans
;
Jeollanam-do
;
Joints
;
Methods
;
Necrosis
;
Osteotomy