Ecologic studies are widely used in all fields of public health on account of accesibility of data. However, two problems related to these studies have been brought up. The first is ecological fallacy occurred in the course of interpreting the ecologic level of exposure-disease associations into individual level. The second is exposure isclassification which leads to serious bias. Nevertheless there is few methodologic study dealing joint effects of the two problems in ecologic study. This study was conducted to suggest an ecologic model not having an ecologic fallacy due to model linkage failure and a methodology for correcting the misclassification bias due to exposure-confounder misclassification. Finally, we suggest a criteria for the ecologic model selection. Main results are as follows: 1. A linear ecologic regression model has a serious ecological fallacy due to model linkage failure and the misclassification bias due to the exposure-confounder misclassification. 2. An interaction ecologic regression model has no ecological fallacy due to model linkage failure, but it is affected seriously by the exposure misclassification. However misclassification bias could be removed mathematically if the information related to the misclassification was known. 3. A log-linear ecologic regression model has an ecological fallacy due to model linkage failure. It is seriously biased as the individual risk ratio are increased, but relatively less affected by the exposure misclassification than interaction ecologic regression model. 4. One of the two ecologic regression model-interaction ecologic regression model and log-linear ecologic regression model- would be selected according to the information of individual risk ratio and exposure misclassification. But using a linear ecologic regression model should be avoided in any circumstance. The above results are only valid in case that there is no other source of ecological fallacy except model linkage failure. Also exposure and confounder are independent each other, measured binary, and having nondifferential misclassification. Since the above assumptions are somewhat strong in considering the real situations of ecologic studies, it is necessary to extend the scope of this study.
Bias (Epidemiology) ; Joints ; Odds Ratio ; Public Health

PURPOSE: Chest irradiation leads to a significant cardiac injury in a number of patients. To prevent, or to reduce the risk of radiation-induced cardiac injury, pentosifylline(PTX), a haemorrheologic agent that improves the blood flow through small blood capillaries has been employed. MATERIALS AND METHODS: One hundred and eighty ICR mice were divided into three study groups : control, radiation alone, and radiation-pentoxifylline. Each group was subdivided into 12 subgroups: 1,3,6 and 10 days and 2, 3, 4, 6, 8, 12, 16 and 20 weeks y observation period after irradiation. The total 15 Gy of radiation was delivered in a single fraction ghrough anterior mediastinal port. Pentoxifylline was injected subcutaneously daily 50mg/k to the back of the mice from the first day of irradiation throughout the observation period. The mice of each group after a certain observation period were sacrificed and sectioned for histopathologic examination of the heart. RESULTS: he findings of acute radiation-induced carditis i.e., heterohpilic infiltration and vacuolization and ballooning of endotherlial cells were onserved upto weeks and reduced sharply afterwards. The late radiation effects including pericarditis with mononuclear cell infiltration, pericardial fibrosis, endothelial cell changes, myocardial degenerationa dn fibrosis present from 4 weeks onwards after irradiation but with various degree of severity. The overall process of pathologic changes of radiation-pentoxify-acute stage was relatively short and the severity of late cardiac toxicity was much lesser compared with those of radiation alone group. CONCLUSION: Pentoxifyllline can effectively reduce the late radiation-induced cardiac injury and resolve the acute effects relatively rapidly.
Animals ; Capillaries ; Endothelial Cells ; Fibrosis ; Heart ; Humans ; Mice ; Mice, Inbred ICR* ; Myocarditis ; Pentoxifylline* ; Pericarditis ; Radiation Effects ; Thorax

Neurosyphilis is an infectious disease of the central nervous system caused by Treponema pallidum spirochete. There are several case reports on atypical manifestations of neurosyphilis, involving progressive cognitive dysfunction and seizures similar to those in herpes encephalitis. Seizures are common in patients with neurosyphilis, but they are usually associated with a positive Jarisch-Herxheimer reaction and status epilepticus is atypical as an initial manifestation of neurosyphilis. Here, we report on neurosyphilis patient whose initial symptom was nonconversive status epilepticus.
Central Nervous System ; Communicable Diseases ; Encephalitis, Herpes Simplex ; Humans ; Neurosyphilis* ; Seizures ; Spirochaetales ; Status Epilepticus* ; Treponema pallidum

PURPOSE: To report an epidemiologic study of keratoplasty in which we analyze basic data of corneal transplants and corneal donations in Korea. METHODS: From June 2004 through October 2004, questionnaires were distributed to 25 hospitals. The questionnaires were about the characteristics of patients registered in eye banks for keratoplasty from May 2001 to April 2003, and about the results of keratoplasties performed from May 2002 to April 2003. RESULTS: The leading corneal diseases in patients registered for keratoplasty were infectious keratitis (22.0%), trauma (21.0%), and pseudophakic and aphakic bullous keratopathy (13.8%), in that order. The leading indications in corneal recipients were: trauma (15.5%), pseudophakic and aphakic bullous keratopathy (13.7%), and infectious keratitis (10.7%), in that order. In 233 cases of keratoplasties, penetrating keratoplasty was performed in 229 cases (98.3%) and lamellar keratoplasty was performed in 4 cases (1.7%). The most common combined surgery was cataract extraction. Common causes of graft failure were rejection of donor cornea and infection. Imported donor corneas were used in sixty-one cases (26.2%) among the 233 total keratoplasties. CONCLUSIONS: We constructed an epidemiologic data base of patients registered for keratoplasty, corneal donation, and the results of keratoplasties throughout Korea.
Cataract Extraction ; Cornea ; Corneal Diseases ; Corneal Transplantation* ; Epidemiologic Studies* ; Eye Banks ; Humans ; Keratitis ; Keratoplasty, Penetrating ; Korea* ; Surveys and Questionnaires ; Tissue Donors ; Transplants

PURPOSE: To report an epidemiologic study of keratoplasty in which we analyze basic data of corneal transplants and corneal donations in Korea. METHODS: From June 2004 through October 2004, questionnaires were distributed to 25 hospitals. The questionnaires were about the characteristics of patients registered in eye banks for keratoplasty from May 2001 to April 2003, and about the results of keratoplasties performed from May 2002 to April 2003. RESULTS: The leading corneal diseases in patients registered for keratoplasty were infectious keratitis (22.0%), trauma (21.0%), and pseudophakic and aphakic bullous keratopathy (13.8%), in that order. The leading indications in corneal recipients were: trauma (15.5%), pseudophakic and aphakic bullous keratopathy (13.7%), and infectious keratitis (10.7%), in that order. In 233 cases of keratoplasties, penetrating keratoplasty was performed in 229 cases (98.3%) and lamellar keratoplasty was performed in 4 cases (1.7%). The most common combined surgery was cataract extraction. Common causes of graft failure were rejection of donor cornea and infection. Imported donor corneas were used in sixty-one cases (26.2%) among the 233 total keratoplasties. CONCLUSIONS: We constructed an epidemiologic data base of patients registered for keratoplasty, corneal donation, and the results of keratoplasties throughout Korea.
Cataract Extraction ; Cornea ; Corneal Diseases ; Corneal Transplantation* ; Epidemiologic Studies* ; Eye Banks ; Humans ; Keratitis ; Keratoplasty, Penetrating ; Korea* ; Surveys and Questionnaires ; Tissue Donors ; Transplants