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.

Introduction: Trauma is the most common cause of death in childhood. Tissue damage, ischemia-reperfusion injury and inflammatory response are mainly responsible for increasing serbest oxiygen radicals. In this study, we aimed to investigate the use of thiol-disulfide and ischemia-modified albumin levels as a diagnostic laboratory parameter in trauma children. Method: Of 202 children, 101 of them were hospitalized in pediatric surgical intensive care unit with trauma and 101 of others were healthy children. Levels of native thiol (-SH), total thiol (SH + SS), dynamic disulfide (SS), dynamic disulfide (SS) / total thiol (SH + SS), albumin and ischemic modified albumin (IMA) were measured from the sera of patients and healthy volunteers. For statistical analyses, SPSS 17.0 was used. Mann-Whitney U and paired correlation test were used where appropriate. p <0.05 was considered significant. Results: The mean age of the patients in the trauma group (Boys: 61 Girls: 40) was 7,88 years and the control group was 8,00 years. In trauma group, 86 of children were exposed to blunt trauma, 15 of children had penetrating trauma and 54 patients had multiple trauma. Surgical procedures were performed in 17 patients. In the trauma group, native thiol, total thiol, dynamic disulfide / total thiol, albumin and IMA levels were significantly lower than that of control (p <0.001) and their dynamic disulfide (p = 0.001) was higher compared to the control. There was no difference thiol-disulfide parametres in trauma groups sub-division as surgery(n=17) vs. follow-up(n=84) groups or multiple trauma(n=54) vs. isolated organ trauma(n=47) groups, or penetrating(n=15) or blunt trauma(n=86) groups. Conclusion: Thiol-disulfide balance and IMA levels show changes in favor of oxidative stress in children with trauma, however, it cannot be used as a laboratory marker that helps to show the system and organ affected by the trauma and to decide the surgical intervention.

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.

Introduction: We aimed to measure the dynamic thiol-disulfide balance and thioredoxin reductase (TrxR) enzyme levels in patients with chronic kidney disease (CKD). Material and Methods: Thirty hemodialysis (HD), 30 CKD patients (stage3-5) and 30 controls were included in the study. The dynamic thiol-disulfide balance was determined by the colorimetric method developed by Erel et al. TrxR levels were determined by ELISA. Results: Native and total thiol levels of CKD and HD patients were significantly lower than that of the control group (p=0.001for both). However, disulfide levels were significantly higher in the HD group (p=0.001), but there was no significant difference between control and CKD groups(p=0.547). A notable negative correlation was found between the native and total thiol levels and IMA(r=-0.628;-0.631),BUN (r=-0.747;-0.747),and creatinine(r=-0.732;-0.721). There was a significant positive correlation between GFR and the thiol levels (r=0.835;0.824). TrxR levels were significantly higher in the patient groups compared to the controls (p=0.001).CRP levels of the patient groups were significantly higher compared to the controls (p=0.001). Conclusions: We have demonstrated that measurement of dynamic thiol-disulfide levels by using colorimetric method can contribute to the diagnosis and follow-up of the disease as a marker, because, it is easily applicable in routine clinical biochemistry laboratories and related with disease severity in CKD patients. Also, we showed that volume correction due to dialysis process should be consider in studies dealing with plasma thiol values and the final results should be given after the correction process.