Xanthine oxidase enzyme activity in keratoconic corneal epithelium.

PURPOSE: To assess the activity of xanthine oxidase (XO) enzyme in keratoconic corneal epithelium and to evaluate its relationship with the keratoconus (KC) severity. METHODS: This prospective and randomized study included 66 eyes of 54 KC patients who received corneal collagen cross-linking treatment and 43 eyes of 32 patients who underwent photorefractive keratectomy due to their refractive error. During surgical procedures, the corneal epithelium was mechanically scraped and gathered to analyze the XO enzyme activity spectrophotometrically. The KC group was subdivided into three groups (stages 1, 2, and 3) according to the Amsler-Krumeich classification. The results were compared between the KC and the control group and in between KC subgroups. RESULTS: No significant differences in age and gender were found between the KC and control groups (p = 0.064 and p = 0.296, respectively). The mean XO activity levels of the KC and control groups were 173.57 ± 87.61 and 223.70 ± 99.52 mIU/mg, respectively (p < 0.001). In KC group, 33 eyes were at stage 1, 19 were at stage 2, and 14 were at stage 3. No significant difference was observed between KC subgroups regarding XO activity levels (p = 0.681). CONCLUSION: In this study, our findings revealed that ultraviolet-related pro-oxidant XO enzyme may have a role in the etiopathogenesis of KC. Further studies are needed to support our result. CLINICAL TRIALS REGISTRATION: When we started this study in 2018, we did not have a "Clinical Trials Registration." However, we have ethics committee approval (date: 21. 02. 2018/No: 22).

Dipeptidyl peptidase-4 and adenosine deaminase enzyme levels in polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies in reproductive age women and insulin resistance (IR) and hyperinsulinism play a critical role in the pathogenesis. Glucagon-like peptide-1 (GLP-1), promotes insulin secretion, inhibits glucagon secretion. GLP-1 is degraded by dipeptidyl peptidase-4 (DPP-4). DPP-4, also interacts with adenosine deaminase (ADA). Therefore, IR may have a significant connection with ADA activity. The aim of this study is to compare levels of DPP-4 and ADA enzymes in PCOS and infertile patients. Forty-four patients with PCOS and 44 infertile patients with normal ovarian reserve were enrolled in the study. Serum ADA, DPP-4, AMH, glucose and insulin levels were measured. HOMA-IR method was used to assess insulin sensitivity. ADA, DPP-4, AMH, HOMA-IR (p < .05) and insulin levels (p < .01) were found to be increased in PCOS patients. Considering all study participants AMH levels were found to be positively correlated with ADA (r: 0.734) and DPP-4 (r: 0.449) levels. Also ADA levels were found to be positively correlated with DPP-4 (r: 0.472), insulin (r: 0.216) and HOMA-IR (r: 0.223). Our findings about the elevation of DPP-4 levels in patients with PCOS suggest that the use of DPP-4 inhibitors may be beneficial in treatment of these patients.

Serum glutathione peroxidase, xanthine oxidase, and superoxide dismutase activities and malondialdehyde levels in patients with Parkinson's disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). Oxidative stress has been hypothesized to play a major role in the development of PD in various studies. This study assessed to investigate oxidative and anti-oxidative status in PD patients. We evaluated oxidant/antioxidant status by measuring serum malondialdehyde (MDA) levels, xanthine oxidase (XO) activities, and activities of antioxidant enzymes, namely, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). The study included 29 patients with PD and 32 healthy subjects as controls. Comparison of oxidative parameters in the patient and control groups revealed significantly higher GSH-Px and XO activities in the patient group. Serum MDA and SOD activities in PD patients were not significantly different from the controls. MDA was negatively correlated with duration of the PD and positively with age of onset. There was a negative correlation between SOD and Hoehn and Yahr (H&Y) stage. According to these results, we suggest that oxidative stress may contribute to the development of PD.

Antioxidative-oxidative balance in epilepsy patients on antiepileptic therapy: a prospective case-control study.

Oxidative stress has been implicated in various disorders, including epilepsy. The aim of this study was to investigate the oxidant and antioxidant status of patients with epilepsy using antiepileptic drugs regularly and to compare them with healthy subjects. We investigated serum catalase (CAT), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and xanthine oxidase (XO) levels in 58 epilepsy patients and 25 healthy controls. Patients were divided into polytherapy (n = 17) and monotherapy (n = 41) groups, and antioxidant status was compared between the two groups and controls. There was no significant difference between the patient and control groups in terms of age or gender (p > 0.05). The mean duration of illness in the patients was 14.8 years, and the mean duration of treatment was 11.4 years. Comparison of the patient and control groups in terms of oxidative stress and antioxidant defence parameters revealed significantly higher MDA, GSH-Px, XO and lower level of CAT, SOD levels (p < 0.05). There were no differences in CAT, MDA, GSH-Px or SOD levels between the monotherapy and polytherapy groups; but the XO level was higher in the monotherapy group (p < 0.05). Although the XO level was decreased by polytherapy, it was higher than in controls. Our study found significantly low level of antioxidants in patients with epilepsy as compared to control. Thus, antiepileptic treatment did not improve oxidative stress parameters. Furthermore, our results show that polytherapy does not change the situation as compared with monotherapy. Antioxidant replacement therapy may benefit these patients.

Oxidative and nitrosative stress in serum of patients with Parkinson's disease.

Parkinson's disease (PD) is one of the common neurodegenerative disorders. Oxidative stress is considered as a contributing factor to the development of PD. The present study aims to investigate serum oxidative stress status in patients with PD. Oxidative stress was assessed by measuring serum nitric oxide levels, lipid hydroperoxide concentrations, and nitric oxide synthase activity. In addition, total serum antioxidant capacity (TAC) was evaluated using the serum 2,2-Diphenyl-1-picryl-hydrazyl (DPPH) free-radical scavenging method in 32 patient with Parkinson's disease and 32 control subjects. Our results indicated that serum nitric oxide and lipid hydroperoxide levels were significantly lower in patients with PD than controls. Moreover, nitric oxide levels were found to be negatively correlated with Unified Parkinson's Disease Rating Scale (UPDRS). However, no statistical difference was observed in total serum antioxidant capacities and nitric oxide synthase activities between patients and controls. The present study indicates that although antioxidant capacity was not changed, lipid hydroperoxide (LPO) level was found decreased. This might show pre-oxidative process in these patients. In addition, decreased nitric oxide (NO) level and negative correlation observed between NO level and disease rating scale implicated a role for NO in the disease process.

Static magnetic field inhibits 5' nucleotidase activity in cancerous and non-cancerous human gastric tissues.

The aim of the present study is to investigate possible effects of static magnetic field (SMF) on 5' nucleotidase (5'NT-CD73) and xanthine oxidase (XO) activities in cancerous and non-cancerous human gastric tissues in order to contribute to the elucidation of the anticancer activity of SMF. Cancerous and non-cancerous human gastric tissues removed from patients by surgical operations were used in the studies. SMF was created using two static magnets. Before and after treatment with SMF, 5'NT and XO activities in the tissue samples were measured. 5'NT activity was found to be lowered, but no significant change was observed in XO activity in the gastric tissues treated with the SMF. Our results suggest that SMF inhibits 5'NT enzyme in gastric tissues significantly. It is supposed that in addition to other proposed mechanisms, inhibition of purine catabolic activity due to inhibition of some key enzymes in the DNA turn-over like 5'NT might also play part in the anticancer activity of SMF.

Serum oxidant and antioxidant status of patients with chronic tension-type headache: possible effects of medical treatment.

Tension-type headache (TTH) is one of the most common and costly primary types of headache in clinical practice, with an unknown etiology. This study assessed to investigate oxidative and antioxidative status in patients with chronic tension-type headache (CTTH), and to evaluate possible effect of medical treatment. The study included 41 CTTH patients and 19 age- and sex-matched healthy subjects without headache as controls. The CTTH group comprised 20 patients receiving treatment and 21 untreated patients. We evaluated oxidant/antioxidant status by measuring serum malondialdehyde (MDA) levels and activities of antioxidant enzymes, namely glutathione peroxidase (GSH-Px) and catalase (CAT). Comparison of oxidative parameters in the patient and control groups revealed significantly lower CAT activities and higher MDA level and GSH-Px activities in the patient group. In the CTTH group, serum CAT activities were found to be significantly decreased in patient groups, while serum MDA levels and GSH-Px activities were found to be higher in the untreated CTTH patients. These findings suggest that oxidative stress is increased in the patients with CTTH, and medical treatment abolishes the stress in part. It has been concluded that antioxidant support might be helpful for the patients with CTTH to prevent oxidant stress and peroxidation damages further.

Decreased antioxidant status in migraine patients with brain white matter hyperintensities.

Migraine patients have an increased risk to develop deep white matter hyperintensities (WMH) than the general population. Oxidative stress is believed to play a role in the pathogenesis of migraine. The present study was undertaken to assess oxidant/antioxidant balance of migraineurs with and without WMH. We hypothesized that increased oxidative stress and decreased antioxidant response may play a role in the pathophysiology of WMH in migraineurs. The study included 32 patients in the migraine group and 17 age- and sex-matched healthy subjects without headache in the control group. The migraine group comprised 18 with WMH and 14 without WMH. We evaluated oxidative status with malondialdehyde (MDA) and to determine the activities of antioxidant enzymes: superoxide dismutase, glutathione peroxidase and catalase (CAT) in serum of migraineurs and controls. Comparison of the patient and control groups for oxidative parameters revealed significantly lower level of CAT and higher level of MDA in the patient group. Two-way comparison for CAT and MDA of the migraine with and without WMH and the controls revealed that CAT serum level significantly decreased in migraine patients with WMH than migraine patients without WMH and controls. In this preliminary study, we demonstrated that the levels of CAT were decreased in migraine patients with WMH compared to patients without WMH and controls. These findings suggest that decreased antioxidant response may play a role in the pathophysiology of WMH in migraineurs. Besides, our results encourage the new treatment and follow-up options based on antioxidant systems.

Effect of Static Magnetic Field on Oxidant/Antioxidant Parameters in Cancerous and Noncancerous Human Gastric Tissues.

Aim. To investigate the effects of static magnetic field (SMF) on oxidant and antioxidant parameters of the cancerous and noncancerous human gastric tissues. Materials and Methods. Gastric tissues obtained from patients with gastric cancer were used in the study. SMF was created by using two static magnets. Before and after treatment with SMF, oxidant and antioxidant parameters were measured in the tissue samples. Results. In the cancerous tissue, superoxide dismutase (SOD) activity was found higher and malondialdehyde (MDA) level was found lower as compared with noncancerous tissue. SMF affects oxidant/antioxidant parameters differently in the cancerous and noncancerous tissues. In this regard, SMF causes increase in SOD activity and decrease in MDA level in the noncancerous tissue. However, it decreases SOD and glutathione peroxidase (GSH-Px) activities and increases MDA level and catalase (CAT) activity in the cancerous tissue. There were no differences between nitric oxide (NO) and nitric oxide synthase (NOS) parameters in or among the cancerous and noncancerous tissues. Conclusions. SMF accelerates peroxidation reactions possibly by suppressing SOD and GSH-Px enzymes in the cancerous gastric tissue. This event caused by SMF might play part in the death of cancer cells, which may be a good supportive vehicle for the cancer therapy.

Effects of aqueous extract from Silybum marianum on adenosine deaminase activity in cancerous and noncancerous human gastric and colon tissues.

OBJECTIVE: Investigation of possible effects of Silybum marianum extract (SME) on adenosine deaminase (ADA) activity in cancerous and noncancerous human gastric and colon tissues to obtain information about possible mechanism of anticancer action of S. marianum. MATERIALS AND METHODS: Cancerous and noncancerous human gastric and colon tissues removed from patients by surgical operations were used in the studies. The extract was prepared in distilled water. Before and after treatment with the extract, ADA activities in the samples were measured. RESULTS: ADA activity was found to be lowered significantly in cancerous gastric tissues but not in noncancerous gastric tissues after treatment with the SME. In the colon tissues, ADA activities were however found to increase after the treatment of SME. CONCLUSION: Our results suggest that the aqueous extract from S. marianum inhibits ADA activity in cancerous gastric tissues significantly. It is suggested that in addition to other proposed mechanisms, accumulated adenosine due to the inhibition of ADA might also play a part in the anticancer properties of the S. marianum.

Static magnetic field inhibits adenosine deaminase activity in cancerous and noncancerous human gastric tissues.

AIM: Investigation of possible effects of static magnetic field (SMF) on adenosine deaminase (ADA) activity in cancerous and noncancerous human gastric and colon tissues to obtain information about possible action mechanism of SMF. MATERIALS AND METHODS: Cancerous and noncancerous human gastric and colon tissues removed from patients by surgical operations were used in the studies. SMF was created by using two static magnets. Before and after treatment with SMF, ADA activities in the tissue samples were measured. RESULTS: The ADA activity was found to be lowered in gastric tissues treated with the SMF. However, no change was observed in the ADA activity of colon tissues. CONCLUSIONS: Our results suggest that SMF inhibits the ADA enzyme in gastric tissues significantly. It is supposed that, in addition to other proposed mechanisms, accumulated adenosine due to the inhibition of the ADA enzyme might also play a part in the anticancer activity of SMF.

Aqueous extract from taxus baccata inhibits adenosine deaminase activity significantly in cancerous and noncancerous human gastric and colon tissues.

OBJECTIVE: To investigate possible effects of aqueous taxus baccata extract on adenosine deaminase (ADA) activity in cancerous and noncancerous human tissues and to clarify mechanism(s) of its anticancer potential. MATERIALS AND METHODS: Cancerous and noncancerous human gastric and colon tissues were used in the study. The extracts were prepared in distilled water. Before and after treatment with the extracts, ADA activities in the tissue homogenates were measured. RESULTS: ADA activity was found to be higher in gastric tissue compared with colon tissue, but no differences were found between ADA activities of cancerous and noncancerous tissues for both as well. In the plant extract studies, it was found that taxus extract significantly inhibited ADA activity both in cancerous and noncancerous gastric and colon tissues. CONCLUSION: Our results suggest that aqueous extract from taxus baccata inhibits ADA activities in both gastric and colon tissues significantly. It is suggested that in addition to other proposed mechanisms, accumulated adenosine due to the inhibition of ADA enzyme might also play part in the anticancer properties of taxus species.