Introduction: The aim was to analyze intracellular oxidised glutathione (GSSG)/reduced glutathione (GSH) and serum thiol/disulfide homeostasis tests in bacterial sepsis (BS) to evaluate the contribution of oxidative stress to etiopathogenesis. Methods: A total of 92 individuals, including 49 patients and 43 healthy volunteers, were included in the present study. The cases who had high probability of BS criteria defined by Singer et al. and positive blood culture were included in the study. The intracellular oxidised and reduced glutathione and thiol/disulfide homeostasis [total thiol-native thiol-disulfide changes] tests were used in the serum samples of 49 patients. Statistical analysis was performed by comparing the results with the control group. Results: When BS and control group were compared, GSH, total glutathione (GSH+GSSG), native thiol and total thiol levels were significantly lower in BS group compared to control group (p<.001). No significant differences were detected between the two groups in terms of GSSG levels. CRP, PCT, WBC and RDW levels were significantly higher in BS group than in control group (p<.001). Conclusions: Total thiol and native thiol levels in serum and intracellular glutathione levels decreased in BS. Disrupted intracellular GSH/GSSG and serum thiol/disulfide homeostasis might have effects on BS pathogenesis by increasing oxidative stress.

Background: Various variants of the covid-19 have started to attract attention recently. The clinical course of these variants and possible predictive parameters are being investigated. This study aimed to examine the relationship between thiol levels, which are indicators of oxidative stress, and variant covid-19 types. Methods: In this cross-sectional study, patients with a diagnosis of classic covid-19 and patients with a diagnosis of variant covid-19 with mild and moderate symptoms followed in the clinical observatory of Ankara city hospital were included in the study group. The patients were divided into two groups according to the covid-19 type as variant and classic covid-19, and a healthy control group is added for comparison. A complete blood count and thiol analysis are performed from the venous blood samples. Obtained results were compared between groups, and the ROC analysis is performed. Results: Thiol levels were significantly lower in patients with a diagnosis of Covid-19 compared to the control group. In terms of WBC, lymphocyte, neutrophil, NLR, ferritin and thiol parameters, patients with variant covid-19 differed significantly from patients with a classic covid-19 diagnosis. Thiol levels’ cut-off values to distinguish between variant covid-19 patients and control group from classical covid-19 patients were almost identical (423 and 422 µmol/L, respectively). Conclusions: It seems possible to use thiol as a sensitive, specific and cost-effective marker to suspect variant covid-19 cases. Since this study is probably the first example in this subject, it would form a basis for further studies. Keywords: Covid-19, SARS-CoV-2, variant covid-19, thiol, oxidative stress.

Background: A crucial balance exists between oxidant and antioxidant mechanisms in the functional immune system. We aimed to evaluate the contributions of balance between these systems to coronavirus disease 2019 (COVID-19), a devastating pandemic caused by viral infection. Method: We analyzed serum oxidant and antioxidant stress parameters according to the clinical and demographic characteristics of children and adults with COVID-19 and compared them against the values of healthy controls. Serum native thiol (NT), total thiol (TT), disulfide, total antioxidant status, total oxidant status, and ischemia-modified albumin levels were evaluated and compared between groups. Results: A total of 79 children and 74 adults were evaluated in the present study, including 46 children and 40 adults with COVID-19, 33 healthy children, and 34 healthy adults. TT, NT, and disulfide levels were significantly lower in the adult COVID-19 group than in all other groups (p = 0.001, p = 0.001, and p = 0.005, respectively). Additionally, TT and NT levels were significantly lower in both pediatric and adult COVID-19 cases with severe disease course than mild/moderate course. TT and NT levels were identified as predictors for the diagnosis of the adult COVID-19 cases and as independent predictors for disease severity in both children and adults with COVID-19. Conclusion: Parameters that reveal the oxidant and antioxidant capacity, including TT and NT, appear to be good candidates for the accurate prediction of the clinical course among patients with COVID-19.

Objective: There is a crucial balance between oxidant and antioxidant defense mechanisms. We aimed to evaluate the role of the balance of these systems in community-acquired pneumonia (CAP) in children. Methods: We analyzed serum oxidant and antioxidant stress parameters according to the clinical and demographic data of children with CAP and compared them with healthy controls. Serum total antioxidant status (TAS), total oxidant status (TOS), and levels of ischemia-modified albumin (IMA), antioxidant enzymes, non-enzymatic antioxidant factors, and plasma thiol were evaluated and compared between the groups. Results: Of 160 children evaluated, 106 had CAP (54 outpatients, 52 inpatients) and the other 54 were healthy subjects (control group). Total thiol and native thiol levels were significantly lower in the inpatient group compared to the outpatient group (p=0.004, p=0.005). Serum IMA differed significantly among the groups (p=0.001), with inpatients showing the highest level. A positive correlation was found between serum IMA and C-reactive protein levels in patients with pneumonia (r=0.351; p=0.001). Conclusion: Parameters that provide information about antioxidant capacity may be useful in the diagnosis and prognosis of pneumonia. Both thiol homeostasis parameters and IMA level seem likely to be influenced by disease severity. Our results suggest that plasma thiol levels and IMA may be good candidate biomarkers to predict the severity of pneumonia in children.