You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
Antioxidant potential of propylthiouracil in patients with psoriasis.
Abstract 1:
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


Title 2:
Concentration of selenium, zinc, copper, Cu/Zn ratio, total antioxidant status and c-reactive protein in the serum of patients with psoriasis treated by narrow-band ultraviolet B phototherapy: A case-control study.
Abstract 2:
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


Title 3:
Oxidative stress and psoriasis: the effect of antitumour necrosis factor‐α inhibitor treatment
Abstract 3:
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


Title 4:
Antioxidants and lipid peroxidation status in the blood of patients with psoriasis.
Abstract 4:
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
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