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Oxidative stress is described as disturbed oxidative balance between increased reactive oxygen species such as hydroxyl radical (OH•), superoxide radical (O 2 −), hydrogen peroxide (H 2 O 2) which occurs during normal cellular metabolism and decreased antioxidants which have scavenging effects on free radicals. Reactive oxygen species resulted from increased oxidative stress attacks on to the double bonds of lipids, proteins and DNA bases, removing one hydrogen atom from structure and initiate to oxidative chain reactions. This process leads to cellular damage and death damaging intracellular macromolecules such as lipids, proteins and DNA. The damage of free radicals is detected measuring oxidative products such as malondialdehyde (MDA), protein carbonyl (PCO) and 8-hydroxyguanine derivatives (8-OHG, 8-hidroksi-2′deoksiguanozin) in body fluids and various tissues. Although considerable amount of studies in this field, the effects of oxidative stress on cellular structures still remain unknown. In this review, we aimed to evaluate the biochemical aspects of oxidative stress, antioxidant systems and their mechanism of actions and oxidative products.

OBJECTIVE: This retrospective study aimed to determine the predictive values of the C-reactive protein (CRP)/albumin ratio (CAR), fibrinogen/albumin ratio (FAR), and neutrophil/lymphocyte ratio (NLR) parameters, which reflect the systemic inflammatory status, for the severity of COVID-19.METHODS: A total of 188 patients diagnosed with COVID-19 were enrolled in this study. Among them, 118 were in the severe group, and 70 were in the non-severe group. Levels of albumin, CRP, D-dimer, procalcitonin, fibrinogen, and hemoglobin; leukocyte, neutrophil, lymphocyte, and monocyte counts; and the FAR, CAR, and NLR were compared between the two groups. RESULTS:The CAR, FAR, and NLR values were significantly higher in the severe group compared to the non-severe group. CAR, FAR, and NLR were positively correlated with leukocyte and neutrophil counts and CRP, procalcitonin, and fibrinogen levels. On the other hand, they were inversely correlated with monocyte (except for NLR) and lymphocyte counts. Receiver operator characteristic analysis showed that the area under the curve (AUC) for CAR, FAR, and NLR was 0.841, 0.737, and 0.802, respectively. CONCLUSIONS: Our investigation revealed that the CAR, FAR, and NLR indices can be used to predict the severity of COVID-19, among which CAR was the best predictor of severe COVID-19.

The coronavirus disease 2019 (COVID-19) infection caused by a novel coronavirus, firstly emerged in Hubei Province, China, spread across all continents of the world in a short time. This respiratory tract infection possess a spectrum of symptoms ranging from mild to life-threatening consequences such as acute respiratory distress syndrome (ARDS) and multiple organ failure. 1,2 COVID-19 patients are classified according to clinical presentation as mild, moderate, severe and critical. The main criteria for classification of patients are involvement of lung and severity of pneumonia. 3 COVID-19 pneumonia is a common cause of hospital admission and death. Computed tomography (CT) images play a key role in determining the presence and severity of pneumonia in COVID-19 patients. 4 Unfortunately, CT scanning may not be

Background Accumulating evidence suggests that oxidative stress is closely related to the pathogenesis and severity of COVID-19 infection. Here, we attempted to compare thiol, total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) levels between COVID-19 patients who need and do not need intensive care unit (ICU) support, and determine whether these markers could be used as predictors of ICU admission. Methods We recruited 86 patients with COVID-19 infection and classified them into two groups according to the level of care: ICU group ( n = 40) and non-ICU group ( n = 46). Thiol, TAS, TOS, and OSI levels were determined and compared between the two groups. Results The levels of thiol and TAS in serum were markedly lower in ICU patients than in the non-ICU patients. On the contrary, TOS and OSI levels were markedly higher. Inflammatory markers, including white blood cell, neutrophil, C-reactive protein, procalcitonin, and ferritin, were negatively correlated with the thiol and TAS, and positively correlated with the TOS and OSI. We determined that areas under the ROC curve for thiol, TAS, TOS, and OSI were 0.799, 0.778, 0.713, and 0.780, respectively. Conclusions Our results revealed that the increase in oxidative stress and decrease in antioxidant levels in COVID-19-infected patients were associated with worsening of disease. Thiol, TAS, TOS, and OSI parameters can be used to distinguish between ICU patients and those who do not, among which thiol was the best predictor of ICU requirement.

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Objective: We aimed to investigate the oxidative stress status in children with β-thalassemia major (β-TM) by measuring native thiol (SH), disulfide (SS) and total thiol (SH + SS) plasma levels. Methods: This study was carried out from November 2017 to March 2018 at the Pediatric Hematology Clinic of the Harran University Medical Faculty Hospital. Blood specimens were collected from 100 participants, including 50 β-TM patients and 50 controls, and SH, SS and SH+SS levels were detected through a newly developed method. Results: SH, SS, SH+SS levels and SS/SH ratio were markedly higher in β-TM patients than in controls. In β-TM group, SH and SH+SS levels were positively correlated with age, albumin and total bilirubin. Serum ferritin level was positively correlated with SH, SH+SS, aspartate transaminase and alanine transaminase. Conclusions: We found that the SS/SH ratio was high in patients with β-TM, which shows increased oxidative stress. This ratio may be considered as a tool for the determination of oxidative status in such patients due to easily calculate, suitable for routine use and economical. How to cite this:Guzelcicek A, Cakirca G, Erel O, Abdullah Solmaz4. Assessment of thiol/disulfide balance as an oxidative stress marker in children with β-thalassemia major. Pak J Med Sci. 2019;35(1):---------. doi: https://doi.org/10.12669/pjms.35.1.307 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.