The evaluation of maternal systemic thiol/disulphide homeostasis for the short-term prediction of preterm birth in women with threatened preterm labour: a pilot study.

The aim of this study was to investigate maternal systemic thiol/disulphide homeostasis (TDH) for the short-term prediction of preterm birth in women with threatened preterm labour (TPL). This prospective study included 75 pregnant women whose pregnancies were complicated by TPL. Thirty-seven of them delivered within 7 days and 38 of them delivered beyond 7 days. Maternal serum samples were collected at the day of diagnosis and the TDH was measured. The maternal disulphide level was significantly higher in pregnant women who delivered within 7 days (25.0 ± 9.8 µmol/L vs 19.4 ± 9.8 µmol/L, p: .015). The threshold value of 22.1 µmol/L for maternal disulphide level predicted delivery within 7 days with 62.2% sensitivity and 60.5% specificity (area under curve 0.651, confidence interval 0.53-0.78). The likelihood ratios for short cervix (≤25 mm) and maternal disulphide level (≥22 µmol/L) to predict delivery within 7 days was found to be 8.7 and 7.3, respectively. The likelihood ratio of combining two tests to predict delivery within 7 days was found to be 11.4. The maternal TDH, which is an indicator of oxidative stress status in maternal compartment, is disturbed in TPL cases who delivered within 7 days. Elevated maternal disulphide level along with cervical length screening predicts a short latency period in pregnancies with TPL. IMPACT STATEMENTWhat is already known on this subject? Spontaneous preterm delivery is one of the major complication of pregnancy and the common cause of neonatal morbidity and mortality. Threatened preterm labour (TPL) is also a frequent complaint in obstetric emergency care units in all around the world. Triaging women with TPL is mandatory for planning further management therapies, since the most of them will eventually deliver at term. Only the measurement of cervical length in symptomatic women has moderate accuracy in predicting preterm delivery. Short cervix is described as an independent predictor of preterm delivery in women with TPL, its predictive accuracy as a single measurement is relatively limited. On this account, several potential markers like foetal fibronectin in the cervicovaginal fluid, salivary oestriol, prolactin in vaginal discharge, maternal serum calponin and interleukin-6 in the amniotic fluid were examined to predict preterm delivery in previous studies. However, none of them represented an excessive predictive accuracy like high sensitivity, PPV or NPV.What do the results of this study add? We report a method which has higher diagnostic and predictive performance to identifying TPL women with high risk of preterm delivery. According to the current literature, there are accumulated data about the correlation between oxidative stress (OS) and preterm delivery regardless of the amniotic membrane status. However, it is still debated whether OS is a trigger or a consequence of preterm delivery. Our study provides evidence for the first time that maternal serum thiol/disulphide homeostasis, which is an indicator of OS in maternal compartment, is disturbed in TPL cases who delivered within 7 days. The high disulphide level in maternal serum, along with cervical length measurement (short cervix) accurately predicts a short latency period in TPL cases.What are the implications of these findings for clinical practice and/or further research? This novel test combination (maternal serum disulphide level and cervical length measurement) could be used clinically to triage pregnant women presenting with TPL, avoiding overtreatment, unnecessary hospitalisations and increased medical costs. The future research would be addressed on reducing maternal OS by using new antioxidant treatment strategies to improve perinatal and long-term childhood outcomes.

Dynamic thiol disulphide homeostasis in patients with surfer's eye: a case-control study.

PURPOSE: The role of oxidative stress in the pathogenesis of pterygium is still unclear. However, abnormal thiol disulfide homeostasis levels are involved in the pathogenesis of various systemic or ocular diseases. We aim to analyze dynamic thiol disulphide homeostasis in patients suffering from conjunctival pterygium using a contemporary technique. METHODS: Thirty-eight subjects suffering from pterygium and 35 age-gender matched healthy volunteers were recruited for the study. For each case, total thiol, disulfide and native thiol levels in blood were obtained. Additionally, the ratio of disulfide over total thiol, native thiol over total thiol and disulfide over native thiol were computed. RESULTS: The level of median native thiol was lower in pterygium group (318.2 µmol/L vs. 333.4 µmol/L) and median disulfide was slightly higher in pterygium group (24.3 µmol/L vs. 22.8 µmol/L) compared to control group. Both disulfide over total thiol and disulfide over native thiol ratios were higher in pterygium group, ratio of native thiol over total thiol was found to be higher in control group. Nevertheless, none of those differences were statistically significant at 95% confidence level. Notably, correlation test pointed to a negative correlation both between pterygium grade and native thiol and between total thiol and pterygium grade in pterygium group (P = 0.03 and 0.02, respectively). CONCLUSION: A negative correlation hinting that slightly weakened dynamic thiol disulphide homeostasis in subjects with pterygium, a local ocular disease. Further studies with larger sample sizes may shed light on this potential relationship and justify systemic antioxidant therapies in these cases.

Plasma thiol/disulphide homeostasis changes in patients with restless legs syndrome.

OBJECTIVES: Restless legs syndrome (RLS) is a common neurological condition. Oxidative stress plays an important role in its pathogenesis. Thiol-disulphide homeostasis (TDH) is a new biomarker of oxidative stress. We studied plasma TDH to determine whether TDH could be used as a new biomarker for RLS and evaluated correlations between TDH and various disease severity rating scales. METHODS: A total of 25 RLS patients and 25 healthy controls were included into the study. TDH status was determined using an automated spectrophotometric analysis method and correlations were analyzed between the TDH status and various disease rating scales in the RLS patients. RESULTS: Plasma total (401±27 µmol/L) and native thiol (354±30 µmol/L) levels were significantly lower, but disulphide level (24±6 µmol/L) was significantly (<0.0001) higher in the RLS patients compared to the controls (455±36, 424±37, 15±5 µmol/L, respectively). The disulphide/native thiol and disulphide/total thiol ratios increased, in contrast, native thiol/total thiol ratio decreased significantly in the RLS patients compared to the healthy controls (<0.0001). The disulphide levels correlated positively with age and various rating scores of the RLS patients. International Restless Legs Syndrome Study Group (IRLSSG) rating score and age correlated negatively with the total and native thiol levels. CONCLUSIONS: Our findings indicate increased oxidative stress in the RLS patients reflected by decreased native and total thiol, and increased disulphide levels and positive correlations between the disulphide levels and various rating scores. We suggest dynamic TDH status to be used as a novel biomarker for the diagnosis and follow-up of the RLS patients.

Dynamic thiol/disulphide homeostasis in patients with hypertrophic cardiomyopathy.

BACKGROUND: In addition to the genetic complexity of hypertrophic cardiomyopathy (HCM), there must be other disease-modifying factors that contribute to its highly variable clinical and phenotypic expression. The authors aimed to investigate serum thiol/disulphide homeostasis as a proxy for oxidative stress using a novel automated assay in patients with HCM. METHODS: This cross-sectional study was conducted on 119 patients with HCM and 52 without HCM. The methods used to measure dynamic thiol/disulphide homeostasis as calorimetric and duplex quantities were developed in 2014. RESULTS: Median serum native thiol levels were significantly lower in patients with HCM than in those without (312.5 µmol/L [285-370 µmol/L] vs 421 µmol/L [349-469.5 µmol/L]; p < 0.001). Serum total thiol levels and disulphide levels were considerably lower than those in the control group ([844.68 ± 195.99 µmol/L vs 1158.92 ± 243.97 µmol/L; p < 0.001], [259.13 ± 65.66 µmol/L vs 375.02 ± 79.99 µmol/L; p < 0.001], respectively). Serum disulphide/native thiol ratios and disulphide/total thiol ratios were significantly lower in HCM patients than in controls (0.80 ± 0.09 vs 0.92 ± 0.05; p < 0.001 and 0.31 [0.30-0.32] vs 0.32 [0.32-0.33]; p < 0.001). Finally, reduced thiol ratios were higher and oxidized thiol ratios were significantly lower in patients with HCM than in controls. CONCLUSIONS: Despite the fact that antioxidant capacity was impaired, the extracellular environment remained in a reducing state by keeping serum disulphide/native thiol ratios low. Therefore, the authors speculate that HCM may behave similarly to tumours with respect to serum thiol-disulphide levels.

Dynamic thiol/disulphide homeostasis metrics as a risk factor for peripheral arterial disease.

OBJECTIVE: To examine dynamic thiol/disulphide homeostasis metrics as a novel risk factor of oxidative stress in patients with peripheral arterial disease. METHODS: One hundred patients with lower extremity peripheral arterial disease (a study group) and 100 control subjects were included in this prospective case-control study. Participants' baseline clinical characteristics and laboratory data including some oxidant/antioxidant status parameters such as albumin, ferroxidase and myeloperoxidase, and thiol/disulphide homeostasis parameters such as native thiol, total thiol and disulphide, as well as native thiol/total thiol, disulphide/native thiol and disulphide/total thiol ratios were all recorded and then compared between the groups. RESULTS: Mean albumin and ferroxidase, and median myeloperoxidase levels were found to be significantly higher in patients with the peripheral arterial disease than in control group (p = 0.045, p = 0.000 and p = 0.000, respectively). Mean native thiol and total thiol, and median disulphide levels were found to be significantly lower in the study group as compared with the control group (p = 0.000, p = 0.000 and p = 0.037, respectively). According to the results of logistic regression analysis, systolic blood pressure, ferroxidase and myeloperoxidase levels were detected to be the independent predictors of peripheral arterial disease. CONCLUSION: Our report is the first one in the literature investigating dynamic thiol/disulphide homeostasis metrics as a novel risk factor of oxidative stress in peripheral arterial disease. Dynamic thiol/disulphide homeostasis metrics may be used as a valuable risk factor of oxidative stress in patients with the peripheral arterial disease since it is readily available, easily calculated and relatively cheap.

Increased oxidative stress is associated with thiol/disulphide homeostasis in clomiphene citrate resistant polycystic ovary syndrome.

The purpose of this study was to evaluate the relation CC resistant PCOS and the thiol/disulphide homeostasis, used as a marker of OS, by measuring that exchange using a novel technique. Sixty women patients admitted to the infertility clinic were evaluated. The patients were divided into two groups. Group 1 comprised 30 infertile PCOS patients with CC resistance; Group 2 was the control group comprising 30 infertile PCOS patients with CC sensitivity. Serum total thiol (p = .024), native thiol (p = .0052), disulphide (p = .003), index 1 (p = .001), index 2 (p = .001) and index 3 (p = .001), HOMA-IR (p < .001) and free testosterone (p < .001) were statistically significant. The independent variables BMI and age effects were adjusted according to the logistic regression method with groups. Significant differences were observed between the two groups in the levels of native thiol (p* = .0042), total thiol (p* = .024), disulphide (p* = .0003), index 1 (p* = .0001) index 2 (p*= .0001), index 3 (p* = .0001), HOMA-IR (p* = .0044), insulin (p*= .032) and free testosterone (p* = .0001) values. The thiol/disulphide homeostasis viewed in favour of OS. Like a reflection of OS in the follicular endocrine microenvironment may be linked with increased thiol/disulphide homeostasis, free testosterone, insulin and HOMA-IR levels.Impact statementWhat is already known about this subject? In previous studies, thiol/disulphide homeostasis was compared between PCOS and control groups. In this study, serum thiol/disulphide homeostasis was measured in infertile PCOS patients resistant to CC for the first time.What do the results of this study add? Disulphide concentrations were significantly higher in patients with CC resistant patients thanthe control group. This shows us that more OS occurs in the CC-resistant group.What are the implications of these findings for clinical practice and further research? Thiol/disulphide homeostasis will be a guide for PCOS management in patients with CC-resistant PCOS.

Analysis of thiol/disulphide homeostasis and oxidant-antioxidant status as a result of exposure to radio-frequency electromagnetic fields.

The aim of the current study is to investigate the effect of daily long-term radio-frequency electromagnetic field (RF-EMFs) exposure on thiol/disulphide homeostasis and oxidant-antioxidant status in the serum of rats. Fourteen male Sprague Dawley rats were divided into two equal groups (n = 7). They were grouped as group 1 (sham-control) and group 2 (2100 MHz exposed). Group 2 rats were exposed to GSM-like signals for 5 h/day, 7 days per week for 14 days. In serum of blood samples, the native, total and native/total thiol levels and antioxidant-oxidant parameters were analyzed. The study revealed that the mean serum total thiol levels of GSM exposure group was rather higher than sham-control group (p = 0,219); the mean serum native thiol levels of GSM exposure group was rather higher than sham-control group (p = 0,416), and the mean serum disulphide levels of GSM exposure group was rather higher than sham-control group (p = 0,566). On the other hand, the mean serum total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) of GSM exposure group were higher than sham-control group. There are no data in the literature, that examine the effects of RF-EMFs on thiol/disulphide homeostasis. The results of this study, indicate that RF-EMFs did not cause oxidative stress and statistically changes in thiol/disulphide homeostasis. More sample sizes and longer-term exposures are needed to confirm the results of this study.

The evaluation of thiol/disulphide homeostasis in recurrent aphthous stomatitis.

The objective of our study was to determine thiol/disulphide homeostasis in recurrent aphtous stomatitis (RAS) patients. A prospective monocentric study was designed. Forty-three recurrent aphtous stomatitis patients and 43 healthy subjects were included to study. Venous blood samples collected and assessed with novel automatic system. Results compared statistically. Disulphide levels were found significantly higher in RAS patients than control group. There was no significant difference between native thiol and total thiol levels. Thiol/disulphide homeostasis is impaired in RAS patients in favor of disulphide levels compared with control group. To the best of our knowledge, the present study is the first examination on the correlation between thiol and disulfide homeostasis in patients with RAS.

The change in Thiol-Disulphide Homeostasis levels as an oxidative stress marker after varicocelectomy: Is there a relationship with sperm parameters?

One of the most important causes of varicocele-related infertility is oxidative stress (OS). One of the markers considered as an indicator of OS is thiol-disulphide homeostasis (TDH). Based on the hypothesis that OS should decrease after varicocelectomy in the light of this information, in our current study, we investigated the relationship between TDH levels and sperm parameters. The data of 56 infertile varicocele men were prospectively analysed. The post-operative total and native thiol levels were significantly higher than those pre-operative total and native thiol levels (477.7 & 436.7 nmol/L, 417.6 & 372.1 nmol/L). Positive correlation was found between total thiol change and change in semen volume (ρ: .277, p: .039), ratio of spermatozoa with normal morphology (ρ: .342, p: .01), progressive (ρ: .334, p: .012) and nonprogressive motility (ρ: .385, p: .003). Positive correlation was also found between native thiol change and semen volume (ρ: .349, p: .008), ratio of spermatozoa with normal morphology (ρ: .362, p: .006), progressive (ρ: .297, p: .026) and nonprogressive motility (ρ: .368, p: .005). Change in the level of TDH was found as positively correlated with progressive and nonprogressive motility change. According to these results, OS decreases with varicocelectomy in infertile patients and TDH can be used as a useful method for measuring OS.

Assessment of thiol/disulphide homoeostasis and ischaemia-modified albumin and their relationship with disease severity in children with chronic urticaria.

BACKGROUND: The pathogenesis chronic urticaria (CU) hasn't been fully understood. In recent years, it has been shown that thiol-disulphide homoeostasis, as an antioxidant system, plays important roles in both healthy individuals and various diseases. In different ischaemia-reperfusion states, high oxidative stress causes ischaemia-modified albumin (IMA) generation. AIM: To investigate thiol/disulphide balance and IMA level in children with CU and their association with disease severity. METHODS: Thirty children with CU and 20 healthy children as controls, aged 1-18 years, were included in this cross-sectional study. In all subjects, total thiol, native thiol, disulphide levels and IMA levels were measured in plasma by spectrophotometry. Disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were calculated. The disease severity was rated by Urticaria Activity Score (UAS). RESULTS: In the children with CU, the levels of native thiol (375.56 ± 56.22 µmol/L) and total thiol (415.69 ± 54.75 µmol/L) were significantly lower than the control group (475.20 ± 71.87 and 511.20 ± 73.73 µmol/L, respectively) (p = 0.000, p = 0.000). The ratio of native/total thiol * 100 was lower in patients than the control group (p = 0.002). IMA was significantly higher in the patient group than control group (p = 0.000). No significant correlation was found between UAS and thiol/disulphide homoeostasis (p > 0.05). The disulphide levels, disulphide/native thiol and disulphide/total thiol levels were found to be higher in patients with positive family history for autoimmune disorders than those without (p < 0.05). CONCLUSION: In children with CU, impaired thiol/disulphide homoeostasis and increased IMA suggest that oxidative stress may play role in the disease pathogenesis.

Maternal serum thiol/disulfide homeostasis in pregnancies complicated by fetal hypoxia.

We aimed to evaluate maternal serum thiol/disulphide homeostasis in pregnancies complicated by fetal distress (FD). A total of 100 patients beyond the 34th week of pregnancy were included in this study, and they were divided into two groups. The study group included 50 patients who had been diagnosed with FD; the control group was composed of 50 patients who had shown no signs of FD and who had undergone an elective (previous) caesarean section (CS). The native thiol, total thiol and native thiol/total thiol (%) concentrations were lower in Group 1 patients than Group 2 patients (p < .001). The disulphide, disulphide/native thiol (%) and disulphide/total thiol (%) concentrations were higher in Group 1 patients than Group 2 patients (p < .001). This study suggests that maternal thiol/disulphide homeostasis is impaired in pregnancies complicated by FD.IMPACT STATEMENTWhat is already known about this subject? Oxidative stress (OS) has previously been investigated in FD. This study reports for the first time a new novel and automatic measurement method.What do the results of this study add? This study shows that the thiol balance shifts in the direction of disulphide in the cases of FD.What are the implications of these findings for clinical practice and further research? Thiol balance can be used for the timely diagnosis of FD.

Could there be any role of thiol disulphide homeostasis and ischemia modified albumin in the pathogenesis of endometrial polyps?

OBJECTIVE: We searched thiol/disulphide homeostasis and ischemia modified albumin (IMA) in patients with and without endometrial polyp (EP) to evaluate whether there is an association between serum oxidative stress markers and EPs. METHODS: A total of 87 women were enrolled into this study. All patients were evaluated with office hysteroscopy, and then those with EPs underwent operative hysteroscopy. 43 of these women had pathologically confirmed EPs (study group) and 44 had not (control group). Fasting blood samples were obtained from the antecubital vein before the procedure in all women. Thiol/disulphide levels were analyzed with a newly developed method by Erel et al. IMA measurement was performed using an indirect method based on the colorimetric assay as previously defined. RESULTS: There were no significant differences between the 2 groups in terms of demographic characteristics including age, body mass index, and past obstetric history. Similarly no significant difference was observed regarding infertility ratio and smoking status. Native thiol, total thiol, and disulphide levels were found to be 263.6±63.3 µmol/l vs. 280.9±63.8 µmol/l (p:0.208), 296.9±64.9 µmol/l vs. 315.2±67.3 µmol/l (p:0.202), and 16.6±6.5 µmol/l vs.17.1±7.8 µmol/l ( p:0.759) in the study and control groups, respectively. There was also no significant difference with regard to serum IMA level (46.5±12.1 vs. 44.9±12.6; p: 0.539). CONCLUSION: Serum thiol/disulphide homeostasis and IMA levels have no significant effect in the pathogenesis of EPs.

Relationship between thiol-disulphide homeostasis and visual evoked potentials in patients with multiple sclerosis.

PURPOSE: To examine the thiol-disulphide homeostasis during an optic neuritis episode in patients with multiple sclerosis and the relationship between this homeostasis and P100 wave latency. MATERIALS AND METHOD: Visual evoked potential reviews of multiple sclerosis patients who presented with an optic neuritis episode were conducted and P100 latencies were measured. Peripheral blood samples were collected from all patients. Native thiol and total thiol concentrations were measured with the automated method that was recently developed. Their amount of disulphide bonds, disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were calculated. The relationship between P100 latency and thiol-disulphide homeostasis was investigated. RESULTS: A significant positive correlation was determined between the disulphide/native thiol ratio and both mean P100 latency and maximum P100 latency (p = 0.021, r = 0.136; p = 0.030, r = 0.177, respectively). DISCUSSION: As the balance of the plasma dominated by antioxidants moves towards the oxidant side, in other words as a higher rate of thiol is oxidised from the thiol pool, P100 latency is extended. N-acetylcysteine and alpha lipoic acid as well as thiol supplements can improve the thiol-disulphide balance, reinforce antioxidant defence and it can help in slowing down the demyelinating damage.

Oxidative stress among L-2-hydroxyglutaric aciduria disease patients: evaluation of dynamic thiol/disulfide homeostasis.

L-2-hydroxyglutaric aciduria (L2HGA) is an autosomal recessive disorder that is caused by deficiency of 2-hydroxyglutarate dehydrogenase. Pathophysiology of brain damage is poorly understood. In recent years, it was proposed that oxidative stress was elevated and led to brain injury. Aim of this study is to evaluate thiol/disulphide homeostasis as an indicator of oxidative stress in L2HGA patients who have been receiving antioxidant treatment. Sixteen L2HGA patients and 16 healthy individuals were included in the study. All the L2HGA patients were regularly followed up and presented neurological dysfunction at different grades. Fourteen patients had been receiving antioxidant treatment. Serum native thiol (-SH), total thiol (-SH + -S-S-) and disulphide (-S-S) levels were measured. Disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were calculated from these values. No significant difference was observed in -SH, -SH + -S-S-, -S-S levels between two groups. In addition to that, no increase of disulphide/native thiol and disulphide/total thiol ratios was detected. Thiol/disulphide homeostasis parameters were also compared between patients who had been receiving and not receiving antioxidant therapy; and between different types of antioxidant therapy and the results did not point to any significant difference. This is the first study that evaluates dynamic thiol/disulphide homeostasis as an indicator of oxidative stress in L2HGA and it has one of the largest sample sizes among previous studies. In our study we suggest that antioxidant therapy should be effective in preventing oxidative stress in L2HGA patients, which has been reported in previous studies and should be a part of standard therapy.

Dynamic thiol/disulphide homeostasis and pathogenesis of Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) is an acute, self-limited, systemic vasculitis of unknown etiology. In the present study, we investigated whether there is a relationship between KD and dynamic thiol/disulphide homeostasis. METHODS: This case-control study involved KD patients and healthy controls. Plasma total, native and disulphide thiol and the disulphide/native, disulphide/total and native thiol/total thiol ratios of all patients and the control group were analyzed simultaneously. RESULTS: A total of 20 patients with KD (male/female, 12/8) and 25 age- and gender-matched healthy controls (male/female, 12/13) were evaluated. Native, total thiol and native thiol/total thiol ratio were significantly lower in KD patients than in the control group (P < 0.001). In contrast, disulphide thiol, disulphide/native thiol and disulphide/total thiol ratios were significantly higher in KD patients than control subjects (P < 0.001). In KD patients with coronary artery lesion (CAL), the native thiol and total thiol were significantly lower than in KD patients without CAL. In KD patients with CAL, the ratios of disulphide/total thiol and disulphide/native thiol were significantly higher than in those without CAL (P = 0.02 and P = 0.02, respectively), whereas the ratio of native/total thiol was significantly lower (P = 0.02). CONCLUSION: The KD patients had lower plasma thiol (native and total) and higher disulphide thiol than controls, indicating that dynamic thiol/disulphide homeostasis might be an important indicator of inflammation in KD. Alteration and shifting of thiol/disulphide homeostasis to the oxidized side are correlated with the pathogenesis of KD and CAL.

Thiol-disulphide balance in infertility secondary to varicocele.

Oxidative stress plays an important role in the development of infertility secondary to varicocele. We aimed to investigate the dynamic thiol-disulphide homeostasis as an oxidative stress marker in the spermatic vein of infertility secondary to varicocele. Sixty-one patients with varicocele were included in the study. Blood was drawn from the median cubital vein and the testicular venous return side before the spermatic vein was separated during surgery. Total thiol, native thiol, disulphide, ischaemia modified albumin (IMA) and albumin values were measured from both the dilated spermatic vein and the median cubital vein. The disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were determined. The mean age of the patients was 27.0 ± 6.68 (15-50) years. While the albumin, native thiol and total thiol values and the native thiol/total thiol ratio were significantly lower (p = 0.004, p < 0.001, p < 0.001, p < 0.001 respectively), the IMA value and the disulphide/native thiol and disulphide/total thiol ratios were significantly higher (p < 0.001, p < 0.001, p < 0.001 respectively) in the samples taken from spermatic venous blood. Thiol-disulphide balance had deteriorated towards disulphide formation in the spermatic vein compared with the peripheral vein. Abnormal thiol-disulphide balance may be an independent risk factor for infertility secondary to varicocele.

A comprehensive study of oxidative stress in patients with somatic symptom disorder.

OBJECTIVE: To investigate oxidative stress parameters [total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), paraoxonase (PON), arylesterase (ARE) and thiol-disulphide homeostasis] in patients who were diagnosed as having somatic symptom disorder in accordance with Diagnostic and Statistical Manual of Mental Disorders-5. METHODS: The study included 41 medication-free patients with somatic symptom disorder and 47 age, sex, and sociodemographic-matched healthy individuals. The patients were administered the Patient Health Questionnaire-15, Somatic Symptom Amplification Scale, Beck Depression Inventory, and Beck Anxiety Inventory. TOS, TAS, OSI, PON, ARE thiol, disulphide levels, and routine biochemical parameters were compared between the two groups. RESULTS: TOS, OSI, disulphide levels, disulphide/native thiol, and disulphide/total thiol ratios were found significantly higher in the patient group compared with the control group (p < 0.001). There was no significant difference in PON, ARE, and TAS parameters between the two groups (p > 0.05). CONCLUSION: This study showed that the level of oxidants increased and oxidative balance was impaired in somatic symptom disorder. Oxidative stress may play a role in the aetiopathogenesis of this disorder. This is the first study to report an association between oxidative stress and somatic symptom disorder.

An Investigation of Oxidative Stress and Thiol/Disulphide Homeostasis in Graves' Disease.

Background and objectives: The aim of this study was to research oxidative stress and thiol/disulphide homeostasis in Graves' patients. Materials and Methods: The study included 33 Graves' patients (research group) and 35 healthy subjects (control group). Serum oxidative stress and thiol/disulphide homeostasis (a new and automated spectrophotometric method developed by Erel and Neselioglu) parameters were studied and compared between the groups. Results: The native and total thiol levels and the native thiol/total thiol ratio were lower in patients with Graves' disease compared to the control group (p < 0.001, p < 0.001, and p = 0.006, respectively). TOS (total antioxidant status), PC (protein carbonyl), OSI (Oxidative stress index), and disulphide/native thiol and disulphide/total thiol ratios were determined to be higher in the Graves' disease group than in the control group (p < 0.001, p = 0.001, p = 0.001, p = 0.004, and p = 0.006, respectively). In the Graves' disease group, the free triiodothyronine (FT3) and free thyroxine (FT4) levels were significantly positively correlated with impaired thiol/disulphide homeostasis and oxidative stress parameters (p < 0.05). Conclusion: The results of the current study demonstrated that oxidative stress and thiol/disulphide homeostasis increased towards disulphide formation due to thiol oxidation in Graves' disease. In addition, a positive correlation of FT3 and FT4 was observed with oxidative stress parameters and impaired thiol/disulphide homeostasis.

Changes in thiol/disulfide homeostasis in juvenile idiopathic arthritis.

BACKGROUND: The pathogenesis of juvenile idiopathic arthritis (JIA) remains unknown, but imbalance between the oxidant and antioxidant defense systems may play a role. Measuring thiols in plasma provides an indirect indication of antioxidative defense. The aim of the present study was to investigate the association between JIA and dynamic thiol/disulfide homeostatic status. METHODS: This case-control study involved 34 JIA patients and 30 age- and gender-matched healthy controls. The patients were divided into subgroups according to Simplified Disease Activity Index (SDAI) score: active, SDAI > 3.3; remission, SDAI ≤ 3.3. RESULTS: Native thiol and total thiol were significantly lower in the JIA group than in the control group (P = 0.001). There was no significant difference in the disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios between the JIA and control groups (P > 0.05). Based on SDAI score, 22 JIA patients were in the remission subgroup, and 12 JIA patients were in the active subgroup. Native thiol and total thiol were significantly lower in the active JIA subgroup than in the remission subgroup (P = 0.001), but there were no significant differences in the other parameters. There was no significant difference in thiol and disulfide levels between systemic-onset JIA and other JIA (P > 0.05). CONCLUSIONS: Plasma thiol is lower in JIA patients, especially during periods of active disease, than in healthy controls, indicating that low thiol might be an important factor in the etiology of JIA and that antioxidant systems are negatively affected by inflammatory diseases, especially during periods of active disease.

Dynamic Thiol/Disulphide Homeostasis in Children and Adolescents with Non-Autoimmune Subclinical Hypothyroidism.

OBJECTIVE: To evaluate the thiol/disulphide homeostasis in children with non-autoimmune subclinical hypothyroidism (SHT). SUBJECTS AND METHODS: Thiol/disulphide homeosta sis, involving native thiol (SH), disulphide (SS), and total thiol (SS + SH), was evaluated in 60 children and adolescents who were negative for thyroid auto-antibodies (anti-thyroid peroxidase, anti-thyroglobulin) and had a thyroid-stimulating hormone (TSH) value of > 5 mIU/L, and in 40 sex- and age-matched healthy control subjects who were negative for thyroid autoantibodies and had normal TSH levels. Lipid profiles and urine iodine levels were also determined. RESULTS: SH (466 ± 32.8 vs. 462 ± 32.1 µmol/L p = 0.59), SH + SS (508 ± 34.0 vs. 506 ± 32.7 µmol/L, p = 0.81), SS (21 ± 5.5 vs. 22 ± 5.8 µmol/L, p = 0.41), SS/SH (4.5 ± 1.2 vs. 4.8 ± 1.3%, p = 0.36), SS/SH + SS (4.1 ± 1.0 vs. 4.3 ± 1.1%, p = 0.36) and SH/SH + SS (91 ± 2.1 vs. 91 ± 2.1%, p = 0.31) levels were similar in children with SHT and control subjects (p > 0.05). There was no difference between total cholesterol, triglyceride, and low-density lipoprotein levels in SHT patients and controls. No difference was detected between the patients with or without iodine deficiency in the SHT group in terms of thiol/disulphide homeostasis parameters. CONCLUSION: The status of dynamic thiol/disulphide homeostasis did not change in children and adolescents with non-autoimmune SHT. Future studies are needed for the evaluation of oxidative stress in patients with long-standing non-autoimmune SHT.