Comparative analysis of thiol-disulfide homeostasis dynamics between elective cesarean section and uncomplicated vaginal delivery: insights into perinatal oxidative balance.

OBJECTIVE: Thiols are organic compounds containing sulfhydryl groups that exert antioxidant effects via dynamic thiol-disulfide homeostasis. The shift towards disulfide indicates the presence of an oxidative environment. Different modes of delivery can affect thiol-disulfide homeostasis. Accordingly, we planned this research to evaluate the effects of the mode of delivery on thiol-disulfide homeostasis in both maternal serum and fetal cord blood samples. PATIENTS AND METHODS: We conducted a prospective case-control study involving two groups: vaginal delivery (n=50) and elective cesarean section (CS) (n=45). The vaginal delivery group exclusively comprised uncomplicated term deliveries, while the CS group included pregnant individuals with scheduled cesarean deliveries due to the absence of spontaneous labor onset. Maternal serum and fetal cord blood samples were collected, and thiol-disulfide exchanges were analyzed using an automated method capable of measuring both aspects of the thiol-disulfide balance. RESULTS: The levels of native thiol (-SH) and total thiol in both maternal serum and fetal cord blood samples were significantly higher in the vaginal delivery group than those in the CS group. An important discovery of our study was that fetal cord disulfide (-SS) level, which may reflect oxidative stress, was higher in newborns born via vaginal delivery when examined alone. However, in both maternal and fetal cord blood, the combined ratios, SS/SH ratio (%), SS/Total thiol ratio (%), and SH/Total thiol ratio (%) were observed to be similar between the groups in both maternal and fetal cord blood. It was observed that as the mother's weight gained during pregnancy increased, SS/SH and SS/total thiol increased (positive correlation), while SH/total thiol decreased (negative correlation). CONCLUSIONS: Our results showed that the dynamic thiol-disulfide homeostasis was greatly influenced by the way of delivery and supported the idea that vaginally-delivered infants may have more oxidative stress.

Thiol-disulfide homeostasis in irritable bowel syndrome.

OBJECTIVE: The etiopathogenesis and pathophysiological mechanism of irritable bowel syndrome (IBS) is not fully known. In this study, evaluating dynamic thiol-disulfide homeostasis (TDH) in patients with IBS was aimed. SUBJECTS AND METHODS: A total of 92 people, 46 IBS patients and 46 healthy sex and aged-matched volunteers, were included in the study. Thiol/disulfide parameters in serum were measured in all cases, and the two groups were compared. RESULTS: Disulfide levels (21.9 ± 5.0 µmol/L vs. 19.4 ± 4.2 µmol/L, respectively; p < 0.001), disulfide/native thiol (5.7%  ± 1.2% vs. 4.9% ± 0.8%, p < 0.001, respectively) and disulfide/total thiol ratio (5.1% ± 0.9% vs. 4.5% ± 0.7%, respectively, p < 0.001) were found to be higher in IBS patients, and native thiol/total thiol ratio (89.8% ± 1.9%, 90.6% ± 1.9%, p < 0.001, respectively) was found to be lower in IBS patients. CONCLUSIONS: In our study, it was shown that TDH is impaired in IBS, which is an important result supporting studies showing that oxidative stress plays a role in IBS. On the other hand, it is thought that this study will contribute to the literature in terms of being the first study evaluating TDH in adult IBS.

Validation of assays for measurement of oxidant compounds in saliva of pigs: Thiobarbituric acid reactive substances (TBARS), carbonyl, and reactive oxygen species (ROS).

Thiobarbituric acid reactive substances (TBARS), carbonyls and reactive oxygen species (ROS) are oxidant compounds that can provide useful information on the oxidative status. Pigs can be affected by oxidative stress in different situations including physiological conditions such as lactation and also in different diseases, and the measurement of these three analytes in saliva could be potentially useful as biomarkers of the redox status in this species. Assays for the measurement of TBARS and carbonyls by spectrophotometry and ROS by luminol-based chemiluminescence in pigs' saliva were analytically validated and were applied in saliva of pigs after an in vitro incubation with different doses of ascorbic acid (AA). All the assays showed a satisfactory analytical precision and accuracy. The 240 h-incubation of saliva samples with 60 mM of AA induced to an increased TBARS and carbonyls production. TBARS, carbonyls and ROS can be estimated in saliva of pigs by the assays validated in this report. In addition, these assays can detect changes in the concentration of these analytes associated to incubation of saliva samples with AA.

Effect of Remote Ischemic Preconditioning in Total Knee Arthroplasty on Thiol-Disulfi de Balance: a Randomized Controlled Study.

PURPOSE OF THE STUDY The purpose of this study was to minimize tourniquet-induced ischemia-reperfusion injury (IRI) in total knee arthroplasty (TKA) surgery using the remote ischemic preconditioning (RIPC) model, as well as to assess antioxidant balance with thioldisulfi de homeostasis (TDH). The secondary goal is to evaluate the impact of RIPC on TKA clinical outcomes. MATERIAL AND METHODS Patients in the ASA I-III group who underwent elective TKA were enrolled in this prospective, randomized, double-blind clinical research. TDH parameters were measured individually in groups with (Group I) and without (Group K) RIPC at the following times: preoperative (T0), right before the pneumatic tourniquet was opened (T1), 1 (T2), 6 (T3), and 24 (T4) hours after it was opened. In addition, at 3-hour intervals, the postoperative pain level was assessed using a visual analog scale (VAS). RESULTS This study included 60 cases (Group K; n=30, Group I; n=30). Both groups had equal native thiol, total thiol, disulfi de levels, disulfi de/native thiol, disulfi de/total thiol, and native thiol/total thiol ratios (p>0.05 for each). The change in native thiol, total thiol, and disulfi de values at T0 and T4 periods, however, was not statistically signifi cant for Group K (p=0.049, p=0.047, p=0.037, and p=0.217, p=0.191, p=0.220, respectively). At the 15th hour, VAS values in group I were considerably lower than in Group K (p=0.002). DISCUSSION This prospective, randomized, controlled trial examined how RIPC affected tourniquet-induced IRI-induced oxidative stress in TKA surgery. Lower native, total, and disulfi de levels at each postoperative time point were signifi cant. RIPC may reduce tourniquet-induced IRI-induced oxidative stress and TDH in TKA surgery. RIPC also reduced postoperative discomfort. CONCLUSIONS Our fi ndings suggest that RIPC may protect against the oxidative stress caused by IRI during limb surgery with a tourniquet and improve postoperative clinical outcomes. Key words: remote ischemic preconditioning, ischemia-reperfusion injury, thiol-disulfi de balance, oxidative stress, total knee arthroplasty.

The relationship between intraoperative body temperature and thiol/disulfide balance in geriatric patients undergoing elective transurethral prostate resection surgery with spinal anesthesia.

OBJECTIVE: We aimed to investigate the relationship between intraoperative body temperature and thiol/disulfide balance in geriatric patients scheduled for elective transurethral prostate resection surgery with spinal anesthesia. PATIENTS AND METHODS: 71 patients classified as categories 1 and 2, according to American Society of Anesthesiologists (ASA) classification, were included in the study. The core temperature of the patients was recorded in the operating room after monitoring, at 5 and 30 minutes after spinal anesthesia. Total thiols, native thiols, disulfide amounts, disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol were calculated as percentages after monitorization (Tpreoperative) and at 60 minutes after spinal anesthesia (Tintraoperative). RESULTS: The disulfide levels in the Tintraoperative period (29±8.9 mmol/L) were higher than the disulfide levels measured in the Tpreoperative period (18.2±8.8 mmol/L) (p<0.001). In the Tpreoperative period, the disulfide/native thiol (%) level was 4.6±2, while the disulfide/total thiol (%) level was 4.2±1.6. In the Tintraoperative period, the disulfide/native thiol (%) level was 8±2.3, while the disulfide/total thiol (%) level was 6.8±1.7. Native thiol/total thiol (%) levels for the Tpreoperative and Tintraoperative periods were 91.5±3.3 mmol/L and 86.3±3.4 mmol/L, respectively. A correlation was found between native, total thiol levels and patient age in the Tpreoperative and Tintraoperative periods. CONCLUSIONS: Oxidative stress can be reduced in geriatric patients with the possibility of developing involuntary perioperative hypothermia by regularly monitoring body temperature and applying warming techniques.

The evaluation of thiol-disulfide homeostasis in children with Triple-A syndrome.

OBJECTIVE: Triple-A syndrome occurs due to the dysfunction of the ALADIN protein as a result of a mutation in the AAAS gene. ALADIN is involved in redox homeostasis in human adrenal cells and steroidogenesis. It has also been shown to have important roles in DNA repair and the protection of cells against oxidative stress. We planned to investigate serum thiol/disulfide homeostasis, which is a part of redox hemostasis in patients with Triple-A syndrome. PATIENTS AND METHODS: The study included patients with the Triple-A syndrome (26 patients) and healthy children (26 patients). Thiol and disulfide levels of patients and healthy groups were compared. In addition, patients with the Triple-A syndrome were divided into 2 subgroups according to the mutation type, and their thiol and disulfide levels were compared. RESULTS: Triple-A syndrome patients had increased native thiol (SH), total thiol (SH+SS) concentrations, and native thiol/total thiol (SH/SH+SS) ratios than healthy controls. However, Triple-A syndrome patients had lowered disulfide (SS), disulfide/native thiol (SS/SH), and disulfide/total thiol (SS/SH+SS) ratios than the controls. When the group with the p.R478* mutation and the group with other mutation were compared, disulfide level, disulfide/native thiol ratio, and disulfide/total thiol ratio were statistically higher in the group with the p.R478* mutation, while native thiol/total thiol ratio was found to be lower. However, no statistical difference was found between native thiol and total thiol levels. CONCLUSIONS: This is the first study in the literature to evaluate thiol-disulfide homeostasis in patients with the Triple-A syndrome. Patients with Triple-A syndrome had an increased level of thiol compared with healthy controls. Comprehensive studies are needed to clarify these thiol levels, which are thought to be compensatory. Also, mutation type affects thiol-disulfide levels.

Evaluation of the effects of empagliflozin on acute lung injury in rat intestinal ischemia-reperfusion model.

BACKGROUND: Empagliflozin is a selective sodium-glucose co-transporter (SGLT2) inhibitor that is approved for the treatment of type 2 diabetes. The beneficial effects of empagliflozin on other organ systems including the heart and kidneys have been proven. The aim of this study is to evaluate the role of empagliflozin on acute lung injury induced by intestinal ischemia-reperfusion (I/R). MATERIALS AND METHODS: A total of 27 male Wistar albino rats were divided into three groups: sham, I/R, and I/R + empagliflozin; each group containing nine animals. Sham group rats underwent laparotomy without I/R injury. Rats in the I/R group underwent laparotomy, 1 h of after ischemia-reperfusion injury (superior mesenteric artery ligation was followed by 2 h of reperfusion). Rats in I/R were given empagliflozin (30 mg/kg) by gastric gavage for 7 days before the ischemia-reperfusion injury. All animals were killed at the end of reperfusion and lung tissue samples were obtained for immunohistochemical staining and histopathological investigation in all groups. RESULTS: Serum glucose, AST, ALT, creatinine, native thiol, total thiol, and disulfide levels and disulfide-native thiol, disulfide-total thiol, and native thiol-total thiol ratios as well as the IMA levels were analyzed and compared among the groups. While intestinal I/R significantly increases serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine levels; did not cause any change in homeostasis parameters and IMA level. Empagliflozin treatment had no significant effect on biochemical parameters. Empagliflozin treatment induced a significant decrease in positive immunostaining for IL-1, IL-6, TNF-alpha, caspase 3, caspase 8, and caspase 9 compared to the I/R group in lung tissue samples. Intestinal I/R caused severe histopathological injury including edema, hemorrhage, increased thickness of the alveolar wall, and infiltration of inflammatory cells into alveolar spaces. Empagliflozin treatment significantly attenuated the severity of intestinal I/R injury. CONCLUSIONS: It was concluded that empagliflozin treatment may have beneficial effects in acute lung injury, and, therefore, has the potential for clinical use.

Diagnostic value of oxidative stress markers in patients presenting with primary dysmenorrhea to the emergency department.

Background and Aim: Primary dysmenorrhea (PD) is a common presentation for emergency departments. This study investigates the diagnostic value of oxidative stress and ischemia markers in patients with PD. Materials and Methods: The participants were classified into the PD group (patients with PD) and the control group (healthy volunteers). Thiol/Disulfide Homeostasis (TDH) parameters (Ds, Disulfide; NT, Native Thiol; TT, Total Thiol) and serum ischemia modified albumin (IMA) levels of the groups were measured. The Numeric Rating Scale (NRS) was used for pain assessment. Bivariate correlation analysis was performed to test the relationship between NRS and oxidative stress parameters. A P < 0.05 was considered significant. Results: A total of 135 patients (PD group, n = 83; Control group, n = 52) were included in the study. PD group had statistically higher oxidant biomarkers (Ds level, Ds/NT ratio and Ds/TT ratio) and lower antioxidant biomarkers (NT/TT ratio) compared to the control group (p = 0.001; 0.003; 0.002, and 0.002, respectively). Serum IMA level in the PD group was higher than in the control group (P = 0.000). There was a positive correlation between IMA and NRS score (r = 0.342, P < 0.01), but no correlation was found between the other oxidative stress parameters and NRS. Conclusions: PD is characterized by increased oxidative stress and ischemia in the endometrium, which can be detected by TDH parameters and serum IMA. NRS score in PD patients is positively correlated with serum IMA level, which suggests IMA level can be valuable to determine the severity of endometrial ischemia and pain in patients with PD.

Dynamic thiol/disulphide homeostasis and ischemic modified albumin levels in isolated oligohydramnios.

OBJECTIVE: Oligohydramnios is defined as amniotic fluid index in ultrasonographic measurement is less than 5 percentile according to gestational age, the amniotic fluid volume is ≤ 5 cm, or if the single deepest dial is < 2 cm. The condition of oligohydramnios that not with fetal structural/chromosomal abnormalities, intrauterine growth retardation, intrauterine infection and maternal disease is described as isolated oligohydramnios (IO). The aim of this study is to examine whether oxidative stress and reactive oxygen species (ROS) have a place in the pathophysiology of IO. MATERIALS AND METHODS: In this prospective case-control study, a total of 126 participants were included. The patient group consisted of 65 patients who were diagnosed IO, and the control group consisted of 61 healthy normal pregnants. Native thiol (-SH), total thiol (-SH + -SS), dynamic disulfide (-SS), IMA values from maternal serum were measured and compared between groups. RESULTS: Maternal serum -SH and -SH + -SS values were significantly lower in the IO group than in the control group (409.47 ± 55.36 µmol/L vs. 437.40 ± 48.68 µmol/L, p = 0.03 and 457.40 ± 63.01 µmol/L vs. 484.59 ± 52.75 µmol/L, p = 0.01). In the IO group when -SS/-SH and -SS/-SH + -SS ratio was found to be statistically significantly higher than control group (5.84 ± 1.1 vs 5.41 ± 0.71, p = 0.01 and 5.2 ± 0.88 vs 4.8 ± 0.58, p = 0.01), -SH/-SH + -SS ratio was significantly lower (89.56 ± 1.7 vs 90.24 ± 1.16, p = 0.01). There was no significant difference in terms of -SS value (p = 0.66). IMA value was significantly higher in the IO group than control group (0.76 ± 0.10 ABSU vs 0.68 ± 0.06, p < 0.01). It is seen as a result of ROC analysis that -SH, -SH + -SS, -SS/-SH, -SS/-SH + -SS, -SH/-SH + -SS and IMA values have a diagnostic value for IO (p < 0.05). CONCLUSION: The thiol/disulfide balance shifted towards oxidative stress in IO compared to control group. So oxidative stress and ROS have a place in the pathophysiology of IO.

Hexagonal boron nitride nanoparticles trigger oxidative stress by modulating thiol/disulfide homeostasis.

BACKGROUND: Hexagonal boron nitride nanoparticles (hBN NPs) are encouraging nanomaterials with unique chemical properties in medicine and biomedical fields. Until now, the optimal hBN NP's dosage and biochemical mechanism that can be used for in vivo systems has not been fully revealed. The main aim of this article is to reveal characteristics, serum and tissue interactions and any acute cytotoxic effect of different dose of hBN NPs for the first time. METHODS: hBN NPs at concentrations varying between 50-3200 µg/kg was administered by intravenous injection to Wistar albino rats (n = 80) divided into seven dosage and control groups. Blood and tissue samples were taken after 24 hours. RESULTS: Our findings suggested that higher doses hBN NPs caused oxidative stress on the serum of rats dose-dependently. However, hBN NPs did not affect thiol/disulfide homeostasis on kidney, liver, spleen, pancreas and heart tissue of rats. Furthermore, hBN NPs increased serum disulfide formation by disrupting the thiol/disulfide balance in rats. Also, LOOH and MPO levels increased at high doses, while CAT levels decreased statistically. CONCLUSION: The results revealed that hBN NPs induce oxidative stress in a dose-dependent manner by modulating thiol/disulfide homeostasis in rats at higher concentrations.

Evaluation of thiol-disulfide homeostasis in pseudoexfoliation glaucoma and primary open-angle glaucoma.

AIMS: This study aimed to compare the serum thiol-disulfide homeostasis, total antioxidant status (TAS), and total oxidant status (TOS) in patients with pseudoexfoliation glaucoma (PEG) patients, primary open-angle glaucoma (POAG) patients, and healthy individuals (control). METHODS: Ninety subjects were included in this study. Three groups were separated as PEG, POAG, and control. All groups were chosen to be similar in terms of age and gender. Blood samples were obtained following an overnight fasting state and were collected on the ice at 4°C. The serum samples were separated from the cells by centrifugation at 3000 rpm for 15 min and were stored at -80°C. Serum samples analyzed for TAS and TOS, native thiol, total thiol, disulfide, and native thiol/disulfide ratio. RESULTS: TAS and TOS levels of PEG patients were 1.2892 ± 0.0905 mmol/L; 5.0191 ± 2.7722 µmol/L, respectively. TAS and TOS levels of POAG patients were 1.2741 ± 0.1252 mmol/L; 4.1674 ± 1.7723 µmol/L, respectively. TAS and TOS levels of the control group were 2.3414 ± 0.1409 mmol/L; 4.0931 ± 0.1107 µmol/L, respectively. The TAS level was significantly lower in PEG and POAG groups compared to control. TOS level showed no significant differ ¬ ence between PEG, POAG, and control groups (P > 0.05). The mean serum total thiol and native thiol levels were significantly lower in patients with PEG compared to POAG and control group; there was no significant difference between the POAG and control group (P > 0.05). The mean serum disulfide level was significantly lower in patients with PEG compared to POAG (P = 0.018). CONCLUSION: Low levels of TAS were observed in patients with glaucoma, which was likely a response to the increased oxidative stress observed in these patients. While total thiol and native thiol levels were higher in the PEG group, the disulfide level was higher in the POAG group. TAS and TOS levels showed no significant difference between POAG and PEG groups.

Diagnostic utility of oxidative and non-oxidative markers for spontaneous bacterial peritonitis in non-malign ascites.

OBJECTIVE: In this study, we aimed to investigate the diagnostic availability of oxidant and antioxidant parameters in ascites for spontaneous bacterial peritonitis (SBP). MATERIAL AND METHODS: This study was carried out between July and October 2018 with 25 patients with SBP and 24 patients without SBP. Patients with acute infection, those taking vitamin supplements and antioxidant medication, smoking and drinking alcohol, and patients without ascites culture were excluded from the study. RESULTS: In patients with SBP compared those without SBP median paraoxonase (3.1 vs 15.6 ; p <0.001), median stimulated paraoxonase (12.6 vs 53.1 ; p <0.001), median arylesterase (769,9 vs 857,5 ; p = 0,003) and median catalase (10 vs 22,2 ; p = 0,003) were found to be lower and median myeloperoxidase (8.1 vs 1.1 ; p <0.001) were found to be higher. There was a positive correlation between paraoxonase levels and stimulated paraoxonase levels, arylesterase levels and catalase levels, there was a negative correlation between paraoxonase levels and myeloperoxidase levels. Paraoxonase levels 3.7 and lower, stimulated paraoxonase levels 25.8 and lower, arylesterase levels 853.4 and lower, catalase levels 11.8 and lower and myeloperoxidase levels 2.7 and more predicted the the presence of SBP with high specificity and high sensitivity. Paraoxonase and stimulated paraoxo-nase levels were found to have superior performance in predicting the presence of SBP compared to arylesterase levels (p <0.05). CONCLUSION: In this study it was shown that paraoxonase, stimulated paraoxonase, arylesterase, catalase and myeloperoxidase activities can be used for the diagnosis and severity of SBP.

Thiol-disulfide homeostasis and ischemia-modified albumin levels as indicators of oxidative stress in welders' lung disease.

Welders' lung disease refers to mixed exposure to different kinds of metals and chemicals from welding fumes, which affect all parts of the respiratory tract including airways and parenchyma together. This study aimed to investigate the oxidative status in patients with welders' lung (PWL) by means of thiol-disulfide homeostasis and ischemia-modified albumin (IMA) levels. The male welder workers diagnosed with welders' lung disease and healthy individuals were recruited in the study. Plasma levels of disulfide, disulfide/native thiol ratio, disulfide/total thiol ratio, IMA, and catalase (CAT) were determined. Pulmonary function test parameters of both groups were compared. The thiol-disulfide homeostasis parameters of PWL and control group were as follows: disulfide (20.5 ± 6.3 vs. 16.2 ± 3.9 µmol L-1, p < 0.001), disulfide/native thiol (4.36 (1.59) vs. 4.0 (1.64), p = 0.024), and disulfide/total thiol (4.01 (1.34) vs. 3.71 (1.41), p = 0.024). IMA levels in PWL were significantly higher than the control group (1.37 (0.27) mg dL-1 vs. 0.49 (0.61) mg dL-1, p < 0.001), whereas CAT activities were significantly higher in the control group (106.6 (54.5) kU L-1 vs. 78.3 (67.8) kU L-1, p = 0.003). The findings of the present study revealed that oxidative stress plays a key role in the pathogenesis of welders' lung disease. Plasma thiol-disulfide homeostasis and IMA levels might be indicators of oxidative stress in PWL.

The relationship between severity of ulcerative colitis and thiol-disulphide homeostasis.

OBJECTIVES: The aim of the study was to determine dynamic thiol-disulphide homeostasis in patients with ulcerative colitis, compare it with those of healthy control and to investigate the relationship between the severity of the disease and homeostasisMETHODS: A total of 78 patients and 58 healthy subjects were included in the study. Serum native thiol, total thiol and disulphide amounts were measured by using a novel automated method. Obtained results were compared and relationships were determined by correlation analysis. RESULTS: Serum native thiol, total thiol, disulphide amounts and disulphide/native thiol percent ratio (index) were significantly lower (p = 0.003 for index ratio and p < 0.001 for other parameters) in patients with ulcerative colitis than in healthy controls. Native thiol, total thiol and disulphide amounts were significantly higher (p < 0.001) in patients with ulcerative colitis in remission than in patients with active ulcerative colitis and near to those of healthy control. There were significant negative correlations between the severity of the disease and thiol-disulphide homeostasis parameters (r = -0.55, p < 0.001 for native thiol; r = -0.64, p < 0.0001 for total thiol; r = -0.65, p < 0.001 for disulphide and r = -0.33, p = 0.011 for index). CONCLUSION: The thiol-disulphide homeostasis was weakened in ulcerative colitis. Strong correlations between the activity of the disease and thiol-disulfide homeostasis indicate that homeostasis may play a role in the pathogenesis of the disease (Tab. 3, Fig. 3, Ref. 30).

Effects of smoking on thiol/disulfide homeostasis.

OBJECTIVE: Cigarette smoking is an important risk factor for many diseases. This study aimed to evaluate whether cigarette smoking is associated with changes in the thiol/disulfide homeostasis (TDH), a novel biomarker of systemic oxidative stress. PATIENTS AND METHODS: Eighty-four smokers and 86 non-smoking healthy volunteers were enrolled. Serum native thiol, disulfide and total thiol levels, disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios were analyzed using a new colorimetric method. Carbon monoxide (CO) levels were measured by a piCO smokerlyzer instrument. RESULTS: The native, total, and native/total thiol levels of smoking patients were significantly lower (p<0.001 for each), and disulfide, disulfide/native thiol, and disulfide/total thiol levels were significantly higher in smokers than the healthy controls (p<0.001 for each). The CO levels of all study participants were negatively correlated with native thiol (r= -0.627, p<0.001), total thiol (r= -0.569, p<0.001), native thiol/total thiol (r= -0.515, p<0.001), and positively correlated with disulfide (r=0.398, p<0.001), disulfide/native thiol (r=0.515, p<0.001) and disulfide/total thiol (r=0.515, p<0.001) levels. CONCLUSIONS: To our knowledge, this investigation is the first in the literature that investigated TDH in cigarette smokers. Our results show that cigarette smoking may lead to oxidative stress and TDH shifts through disulfide side compared to the healthy group. Further studies with larger sample size are needed to confirm our results for showing the changes in TDH to contribute to the clinical practice.

Thiol-disulphide homoeostasis as an oxidative stress marker in men with varicocele.

Oxidative stress is the most common factor leading to infertility in men with varicocele. Reactive oxygen species and other markers of oxidative stress are measured to predict the extent of oxidative stress. Thiol groups are important antioxidants and essential molecules protecting organism against the harmful effects of reactive oxygen species. Thiol-disulphide homoeostasis is a unique, easy and new method to demonstrate oxidative stress. The aim of this study was to determine thiol-disulphide homoeostasis as an oxidative stress marker in infertile men with varicocele. The hormonal profile and parameters of thiol-disulphide homoeostasis were studied in 46 infertile men with varicocele, 70 fertile men with varicocele and 37 fertile controls. Infertile men with varicocele had significantly higher disulphide concentrations and disulphide/native thiol, disulphide/total thiol and native/total thiol ratios than those of fertile men with varicocele and fertile controls. According to these results, the blood plasma of patients with varicocele contains excessive oxidative stress, even in men with normospermia, and therefore, thiol-disulphide homoeostasis may be useful as an oxidative stress marker in men with varicocele.

Thiol/disulfide homeostasis in postmenopausal osteoporosis.

AIM: To evaluate the impact of postmenopausal osteoporosis on thiol/disulfide homeostasis. MATERIALS AND METHODS: A total of 75 participants were divided into two groups: Group 1 (n = 40) was composed of healthy postmenopausal women, and group 2 (n = 35) was composed of women with postmenopausal osteoporosis. Clinical findings and thiol/disulfide homeostasis were compared between the two groups. RESULTS: The disulfide/native thiol ratio was 8.6% ± 3.6 in group 1 and 12.7% ± 8.4 in group 2 (p = 0.04). The disulfide/native thiol percent ratio was significantly higher in group 2 after adjustment for the years since menopause and age (p < 0.05). The native thiol/total thiol percent ratio was 85.6% ± 4.8 in group 1 and 73.8% ± 24.9 in group 2 (p = 0.01). The native thiol/total thiol percent ratio was significantly lower in group 2 after adjustment for the years since menopause and age (p < 0.05). CONCLUSION: Thiol/disulfide homeostasis shifted to the disulfide side independent of age and years since menopause in postmenopausal osteoporosis.

Thiol/disulphide homeostasis levels in erectile dysfunction patients.

This study explored the use of thiol/disulphide homeostasis as a novel oxidative stress marker in patients with erectile dysfunction (ED). Fifty-five patients aged 40-57 were divided into two groups: Group I (International Index of Erectile Function [IIEF-5] score between 22 and 25, n = 20) and Group II (IIEF-5 score < 22, n = 35). Blood samples were used to evaluate hormone levels, lipid profile and thiol/disulphide levels. A novel, fully automated method measured plasma native thiol, total thiol and disulphide levels. Mean age, body mass index, total testosterone, HbA1c, triglyceride, atherogenic index (AIP) and total cholesterol levels did not significantly differ between Groups I and II (p > .05). IIEF-5 correlated weakly with native thiol level. Although non-statistically significant, native thiol (431 [SD: 105] µmol/L vs. 404 [110] µmol/L) and total thiol (426 [64] µmol/L vs. 41 [78] µmol/L) levels were lower in the ED group compared to the controls, and disulphide (14 [11] µmol/L vs. 18 [9] µmol/L) levels were higher. Mean disulphide/native thiol and mean disulphide/total thiol ratios did not statistically differ between groups. There was a weak positive correlation between AIP and total cholesterol/HDL and disulphide and disulphide/total thiol ratios. Thiol/disulphide haemostasis levels are not a single factor in ED pathophysiology but may contribute.

Thiol/disulphide homeostasis in Bell's palsy as a novel pathogenetic marker.

OBJECTIVES: The aim of this study was to investigate the relationship between Bell's palsy and a novel oxidative stress parameter, thiol/disulphide homeostasis. DESIGN: A prospective study evaluating oxidative stress in Bell's palsy. SETTING: This research took place in the department of Otorhinolaryngology, Ataturk Training and Research Hospital. PARTICIPANTS: Totally, 77 patients with Bell's palsy and 38 healthy controls were included in this study. MAIN OUTCOME MEASURES: The blood levels of total and native thiol and disulphide activity were assessed, and their levels were compared in the patients and controls. RESULTS: There were statistically significant differences between the patients and controls regarding thiol/disulphide parameters. The mean native thiol and total thiol were significantly lower and disulphide levels were higher in the Bell's palsy than controls. On binary logistic regression analysis, the created model showed 45.3% variation. The cut-off value was 18.95 for disulphides. CONCLUSION: Native and total thiol levels were low in the Bell's palsy. This metabolic disturbance may have a role in the pathogenesis of Bell's palsy.

Oxidative stress parameters in localized scleroderma patients.

Localized scleroderma (LS) (morphea) is a chronic, inflammatory skin disease with unknown cause that progresses with sclerosis in the skin and/or subcutaneous tissues. Its pathogenesis is not completely understood. Oxidative stress is suggested to have a role in the pathogenesis of localized scleroderma. We have aimed to determine the relationship of morphea lesions with oxidative stress. The total oxidant capacity (TOC), total antioxidant capacity (TAC), paroxonase (PON) and arylesterase (ARES) activity parameters of PON 1 enzyme levels in the serum were investigated in 13 LS patients (generalized and plaque type) and 13 healthy controls. TOC values of the patient group were found higher than the TOC values of the control group (p < 0.01). ARES values of the patient group was found to be higher than the control group (p < 0.0001). OSI was significantly higher in the patient group when compared to the control (p < 0.005). Oxidative stress seems to be effective in the pathogenesis. ARES levels have increased in morphea patients regarding to the oxidative stress and its reduction. Further controlled studies are required in wider series.