***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE There is growing evidence supporting the reactive oxygen species ( ROS ) in the pathogenesis of psoriasis . Propylthiouracil(PTU ) , an antithyroid drug , has been shown to have beneficial effects on psoriasis . The aim of this study was to investigate both disturbances in oxidant/antioxidant system in psoriasis and whether PTU , shown to have immunomodulatory effects and antioxidant potential , has effects on oxidant/antioxidant system and clinical improvement in psoriatics . DESIGN AND METHODS Malondialdehyde ( MDA ) , end product of lipid peroxidation , superoxide dismutase ( SOD ) and glutathione peroxidase ( GSH-Px ) , and antioxidant enzymes were measured in plasma , erythrocytes and skin biopsies of psoriatics who were resistant to conventional therapy before and after 8 weeks of oral treatment with PTU ( 300 mg/day ) or PTU/thyroxine ( 25 microg/day- to prevent possible hypothyroidism ) . The same parameters were also studied in healthy controls .  Psoriasis Area and Severity Index ( PASI ) scores were used to evaluate the severity of the disease , and routine analyses and thyroid function tests were measured during the study . RESULTS Increased baseline MDA in all sample s were found to be lower . In addition baseline SOD and GSH-Px in skin and erythrocytes were also lower . The increased plasma SOD levels in skin and erythrocytes of the study groups was found to be higher and lower , respectively in all patients after the treatment . No tissue parameters or erythrocyte GSH-Px were different from control levels at the end of the study . Significant clinical improvement and decreased PASI scores were observed in all patients . Post treatment TSH levels were higher in all patients , but these levels were within the reference range and none had clinical hypothyroidism . CONCLUSION These findings may provide some evidence for a potential role of increased lipid peroxidation and decreased antioxidant activity in psoriasis . PTU may be considered as treatment model in psoriasis , in particular for resistant cases , because of its antioxidant potential , and also antiproliferative and immunomodulatory effects BACKGROUND Psoriasis is a common , an inflammatory skin disease . Trace elements may play an active role in the pathogenesis of psoriasis . OBJECTIVE The aim of this study was to estimate the concentration of selenium ( Se ) , zinc ( Zn ) , copper ( Cu ) and Cu/Zn ratio as well as total antioxidant status ( TAS ) and c-reactive protein ( CRP ) in the serum of patients with psoriasis . METHODS In this case-control study sixty patients with psoriasis and fifty-eight healthy people were examined .  Serum levels of Se , Zn and Cu  were determined by atomic absorption spectrometry .  Cu/Zn ratio was calculated . TAS was measured spectrophotometrically . CRP was analyzed by immunoturbidimetric method . Clinical activity of psoriasis was evaluated using Psoriasis Area and Severity Index ( PASI ) . RESULTS Serum concentration of Se in patients with psoriasis ( 71.89±16.90μg/L ) was lower as compared to the control group ( 79.42±18.97μg/L ) and after NB-UVB . Cu level of patients was higher ( 1.151±0.320mg/L ) as compared to controls ( 1.038±0.336mg/L ) , but Zn level did not differ . We observed higher Cu/Zn ratio ( p<0.05 ) in examined patients than in the control group and after NB-UVB . We found decrease TAS before and after NB-UVB . CRP levels was found to be normal range . A significant correlation coefficient between CRP and Cu/Zn was observed . CONCLUSIONS The study showed some disturbances in the serum levels of trace elements and TAS in psoriatic patients Background Psoriasis is a chronic , inflammatory skin condition associated with a high frequency of cardiovascular events . Modifications of plasma lipids , and an increase in the levels of biochemical markers of inflammation and lipid peroxidation have been reported in subjects with psoriasis , suggesting a relationship between psoriasis , inflammation and oxidative damage The aim of this research was to determine levels in blood of vitamin E , beta carotene , lipid peroxidation as malondialdehyde ( MDA ) , reduced glutathione ( GSH ) and glutathione peroxidase ( GSH-Px ) activity in patients with psoriasis . Studies were carried out on 34 patients with moderate and severe psoriases and healthy age-matched controls .  Red blood cell ( RBC ) and plasma sample s from healthy and patient subjects were taken . Levels of GSH and the activity of GSH-Px in both plasma and RBC sample s were significantly ( P<0.001 ) lower in patients with psoriasis than in controls , whereas beta carotene levels in plasma and MDA levels in RBC sample s were significantly ( P<0.01 , P<0.001 ) higher in patients with psoriasis than in controls . However , vitamin E and MDA levels in plasma did not differ statistically . Although being far from conclusive , these results provide some evidence for a potential role of increased lipid peroxidation and decreased antioxidants in psoriasis 
    Output:
    
Moreover , the combined results showed a significant difference in the TAS , MDA , and CAT levels in patients with mild vs. moderate psoriasis and moderate vs. severe psoriasis .
TAS and CAT levels in psoriasis patients were significantly lower than in healthy controls , whereas the TOS and MDA levels were significantly higher .
Furthermore , the TAS , MDA , and CAT levels are associated with the severity of disease .
These results indicate that redox imbalances play a major role in the pathogenesis of psoriasis