The study was conducted on patients who were admitted and/or were being followed up (under the diagnosis of BD) by the Dermatology Outpatient Clinic. Behçet patients (n=25) were diagnosed by the criteria of the International Study Group for Behçet's Disease1
. Briefly, recurrent oral ulceration plus two of recurrent genital ulceration, eye lesions, skin lesions, or positive pathergy test were needed for the diagnosis. The duration of disease ranged 1-20 years (mean: 5.94 years). Ten patients were receiving colchicine therapy (in a dose of 1.5 mg daily) at the time of the study.
RAS cases (n=27) were chosen among patients who were admitted to the Dermatology Outpatient Clinic. They were diagnosed as having RAS according to several criteria; such as minor aphthous, major aphthous or herpetiform ulceration observed by dermatologist at least three times in 12-month period. These cases were not receiving any treatment nor did they have any other symptoms of BD. No patients, neither those with BD nor those with RAS had any diseases such as diabetes mellitus, coronary heart disease, hypertension, cancer or any other disease affecting antioxidant enzyme activities.
The control group (n=45) comprised age and sex matched healthy voluntary health staff.
All reagents were purchased from Sigma Chemical Co (St. Louis, MO, USA) and Merck (Darmstadt, Germany).
After overnight fasting, blood samples were drawn from the subjects. They were centrifuged immediately and the serum and plasma samples were kept at –80ºC until assaying.
Preparation of haemolyzates: After centrifugation heparinised blood samples, haemolysates which were prepared as previously described by Sözmen et al.7, were used immediately for determination of SOD CAT activities and TBARS levels. The haemoglobin values were measured by Drabkin's method.
SOD activities were measured according to Sözmen et al.15 based on the inhibition of autoxidation epinephrine by SOD at 480 nm, with a LKB Ultraspec 2 spectrophotometer (LKB Biochrom Ltd, Cambridge, England).
CAT activities were also determined as described by Sozmen et al.15 in which the degradation of peroxide is recorded spectrophotometrically at 240 nm.
TBARS levels were performed by incubation with TBA solution for 30 min at 95° C 30 min12.
Serum PON1 activities were assayed with or without addition of NaCl (1M) as basal and salt-stimulated activity16. Individuals were classified for PON1 phenotype using the antimode of a histogram of PON1 as proposed by Eckerson17.
Other serum parameters (total cholesterol, triglyceride, LDL-cholesterol, HDL-cholesterol) were determined by routine laboratory methods using a Hitachi 705 autoanalyser.
All statistical analysis were performed by the statistical package SPSS for Windows, version 10.0 (SPSS, Chicago, IL). Correlation was calculated as Spearman correlation coefficients. For comparison of means, the Newman-Keulls multiple range test and Mann Whitney U test were used to analyse the results. For distribution of allele frequencies between the groups, the chi-square test was used. In order to determine the risk ratio, a likelihood test was performed.