The association of CAT-262C/T polymorphism with catalase activity and treatment response in juvenile idiopathic arthritis.

Oxidative stress is believed to be of great importance for both the etiology and the persistence of juvenile idiopathic arthritis (JIA). The aim of this study was to investigate the association of -262C/T polymorphism of the catalase (CAT) gene with JIA, as well as to evaluate whether this polymorphism can influence plasma CAT activity and outcome in JIA patients treated with etanercept. A total of 154 subjects (60 JIA patients and 94 healthy volunteers) were screened for CAT-262C/T gene polymorphism using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Plasma CAT activity was determined using the spectrophotometric method according to Goth, prior to and 12 months after anti-TNF (etanercept) therapy. Clinical outcome was assessed using the JIA ACR (American College of Rheumatology) response criteria. The genotype and allele frequency distributions of CAT-262C/T polymorphism in the patients were significantly different from those of the controls (p = 0.014, p = 0.006). The TT genotype (polymorphic homozygous) was associated with a 4.36-fold higher likelihood of having JIA (95% CI 1.545-12.323, p = 0.005) as compared to the CC genotype (wild-type). At month 12 of treatment, JIA patients, carriers of the CC genotype, showed significantly higher plasma CAT activity (p = 0.004) and achieved the JIA ACR 70 response more often (p = 0.003) than the patients, carriers of the CT/TT genotype. This is the first study implying the possible association of CAT-262C/T polymorphism with JIA. The results suggest the potential protective effect of the CC genotype, with regard to CAT activity and treatment outcome.

The Impact of MGMT Promoter Methylation and Temozolomide Treatment in Serbian Patients with Primary Glioblastoma.

Background and objective: Despite recent advances in treatment, glioblastoma (GBM) remains the most lethal and aggressive brain tumor. A continuous search for a reliable molecular marker establishes the methylation status of the O6-methylguanine-DNA methyltransferase (MGMT) gene promoter as a key prognostic factor in primary glioblastoma. The aim of our study was to screen Serbian patients with primary glioblastoma for an MGMT promoter hypermethylation and to evaluate its associations with overall survival (OS) and sensitivity to temozolomide (TMZ) treatment. Materials and methods: A cohort of 30 Serbian primary glioblastoma patients treated with radiation therapy and chemotherapy were analyzed for MGMT promoter methylation and correlated with clinical data. Results: MGMT methylation status was determined in 25 out of 30 primary glioblastomas by methylation-specific PCR (MSP). MGMT promoter hypermethylation was detected in 12 out of 25 patients (48%). The level of MGMT promoter methylation did not correlate with patients' gender (p = 0.409), age (p = 0.536), and OS (p = 0.394). Treatment with TMZ significantly prolonged the median survival of a patient (from 5 to 15 months; p < 0.001). Conclusions: Due to a small cohort of primary GBM patients, our study is not sufficient for definitive conclusions regarding the prognostic value of MGMT methylation for the Serbian population. Our preliminary data suggest a lack of association between MGMT promoter methylation and overall survival and a significant correlation of TMZ treatment with overall survival. Further population-based studies are needed to assess the prognostic value of the MGMT promoter methylation status for patients with primary glioblastoma.

Vitamin D Receptor Gene Polymorphisms in Serbian Patients With Bronchial Asthma: A Case-Control Study.

Vitamin D and single nucleotide polymorphisms (SNPs) in vitamin D receptor (VDR) gene are potentially involved in the pathogenesis of bronchial asthma (BA); however, precise mechanisms by which vitamin D reduces the inflammation and the role of VDR SNPs in BA are not completely understood. The aim of this study was to examine the possible associations of FokI, BsmI, ApaI, and TaqI SNPs with BA. A total of 168 subjects were screened for VDR SNPs using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method. The obtained results showed statistically significant differences in the distribution of FokI genotypes (df = 2; P = 0.008) and alleles (P = 0.002; OR = 0.446; 95%CI = 0.264-0.752) between patients and controls. Distributions of BsmI, ApaI, and TaqI genotypes and alleles did not show statistical differences. BsmI, ApaI, and TaqI SNPs are in linkage disequilibrium (LD) in the whole studied group, as well as in BA patients and controls. The strongest LD was observed between BsmI and TaqI (r2 = 0.69 for all subjects in the study; r2 = 0.75 in BA; r2 = 0.64 in controls), while lower values of LD were observed for BsmI and ApaI, and ApaI and TaqI SNPs. This is the first study that examined the association of VDR SNPs (FokI, BsmI, ApaI, and TaqI) in Serbian patients with BA indicating protective effect of FF genotype and F allele of FokI SNP on BA development. J. Cell. Biochem. 118: 3986-3992, 2017. © 2017 Wiley Periodicals, Inc.

The Differences in the Cellular and Plasma Antioxidative Capacity Between Transient and Defined Focal Brain Ischemia: Does it Suggest Supporting Time-Dependent Neuroprotection Therapy?

There are many opened questions about the precocious role of oxidative stress in the physiopathology of the early stage of transitory ischemic attack (TIA) and defined focal brain ischemia, as well as about its correlation with clinical severity, short-lasting and clinical outcome prediction in these conditions. The study evaluates the values of glutathione (GSH), glutathione peroxidase, and superoxide dismutase (SOD) in hemolysates and total thiol content (-SH), advanced oxidation protein products (AOPP), SOD, and malondialdehyde (MDA) in plasma, in TIA and stroke patients in the early stage of their neurological onset. The results are interpreted in view of the potential relationship between tested parameters and clinical severity and clinical outcome prediction. Better hemolysates' and total antioxidant profile with higher values of AOPP were observed in TIA compared to stroke patients (p < 0.05). The stroke patients with initially better clinical presentation showed better antioxidant profile with lower values of AOPP (p < 0.05). In TIA patients, this was observed for GSH, -SH content, and AOPP (p < 0.05), which correlated with a short risk for stroke occurrence in this group (p < 0.01). Beyond MDA values, all tested parameters showed correlation with clinical outcome in stroke patients (p < 0.05). The measurement of oxidative stress in TIA and stroke patients would be important for identifying patients' subgroups which might receive supporting therapy providing better neurological recovery and clinical outcome. That approach might give us an additional view of a short-lasting risk of stroke occurrence after TIA, and its clinical outcome and prognosis.

Arginase activity and lecithin/sphingomyelin (l/s) ratio in the amniotic fluid of pregnant women.

Arginase activity is important in polyamines and nitric oxide production which are required for the normal growth of placenta and embryo. A considerable arginase activity is observed in amniotic fluid in women at the end of pregnancy. Lecithin to sphingomyelin (L/S) ratio is widely used in order to assess fetal lung immaturity and prevention of neonatal respiratory distress syndrome, the major cause of neonatal morbidity and mortality. The purpose of our study was to determine if there is a relationship between arginase activity and L/S ratio in amniotic fluid. The study included 170 pregnant women, 18-43 years old, with normal and pathological pregnancy. The arginase activity was measured on the basis of the determination of the amount of liberated ornithine from arginine as substrate. The L/S ratio was done by using a thin layer chromatography. Increased level of arginase activity correlates with the fetal lung maturity. Arginase activity and L/S values may be useful biochemical data, for intrauterine baby maturity.

Glutathione homeostasis disruption of erythrocytes, but not glutathione peroxidase activity change, is closely accompanied with neurological and radiological scoring of acute CNS inflammation.

OBJECTIVES AND METHODS: The levels of glutathione (GSH) and glutathione peroxidase (GPx) activity were measured in the erythrocytes of 50 patients with clinically isolated syndrome of CNS (CIS) and 57 patients with relapsing remitting multiple sclerosis (RRMS). RESULTS: A decrease in GSH content and GPx activity showed significance in both study groups compared to the control values (p = 0.0025 and 0.007 for GSH and p = 0.005 and 0.003 for GPx, in CIS and RRMS patients, respectively). The depletions were more pronounced in RRMS than in CIS patients (p = 0.009 for GSH and p = 0.031 for GPx). The results significantly verify the negative correlations between GSH values and clinical severity (r = -0.513, p = 0.004), radiological findings (r = -0.351, p = 0.008) and disease duration (r = -0.412, p = 0.0025) in CIS patients. The same correlations were observed in RRMS patients between GSH values and clinical severity (r = -0.498, p = 0.004) and patients' radiological features (r = -0.454, p = 0.005). No correlations were observed between GSH values and other patient characteristics, or between GPx activity and all tested patient characteristics (p > 0.01). CONCLUSIONS: The results indicate that GSH content and GPx activity both decreased below the normal range and were accompanied with neuroinflammation, but although both might have great importance in neuroinflammation development, the data presented here confirm that only GSH might serve as a marker which is closely correlated with neurological and radiological scoring of acute CNS inflammation.

Cerebrospinal fluid and plasma oxidative stress biomarkers in different clinical phenotypes of neuroinflammatory acute attacks. Conceptual accession: from fundamental to clinic.

Oxidative stress is revealed as the main contributor in the pathophysiology of neuroinflammation. Analyzing plasma and cerebrospinal fluid (CSF) of patients with different clinical phenotypes of neuroinflammation, defined as clinically isolated syndrome (CIS), and those defined as relapsing remitting multiples sclerosis (RRMS), we tested peripheral and CNS oxidative stress intensity in these neuroinflammatory acute attacks. All obtained values changes were assessed regarding clinical and radiological features of CNS inflammation. The obtained results revealed an increase in malondialdehyde levels in plasma and CSF in CIS and RRMS patients compared to control values (p < 0.05). The obtained values were most prevailed in both study group, CIS and RRMS, in patients with severe clinical presentation (p < 0.05). Measured activities of catalase and total superoxide dismutase were higher in CIS and RRMS patients in plasma compared to control values (p < 0.05), parallel with an increased catalase activity and decrease in superoxide dismutase activity in CSF regarding values obtained in control group (p < 0.05). The positive correlations regarding clinical score were obtained for all tested biomarkers (p < 0.01). Although the positive correlations were observed in MDA levels in plasma and CSF, for both study patients, and their radiological findings (p < 0.01), and a negative correlation in plasma SOD activity and CIS patients' radiological findings (p < 0.01), no other similar correlations were obtained. These findings might be useful in providing the earliest antioxidative treatment in neuroinflammation aimed to preserve total and CNS antioxidative capacity parallel with delaying irreversible, later neurological disabilities.

Association of serum bilirubin and uric acid levels changes during neuroinflammation in patients with initial and relapsed demyelination attacks.

In order to examine the endogenous antioxidants values in the earliest phase of demyelination, we have determined bilirubin and uric acid (UA) serum values in the patients with clinically isolated syndrome (CIS) and relapsing remitting multiple sclerosis (RRMS), regarding their clinical disability, measured by Extended Disability Status Scale (EDSS), Magnetic Resonance Imaging (MRI), disease duration, gender and other parameters. The bilirubin and UA levels were lower in CIS and RRMS patients than in control group, whether male or female (p < 0.05). The bilirubin and UA levels were decreased in RRMS compared to CIS patients (p < 0.05). Regarding EDSS, MRI and disease duration, obtained values of bilirubin and UA were higher in both study groups in patients with lower EDSS, lower MRI lesion number and shorter disease duration (p < 0.05). The greatest significance in decreased bilirubin and UA levels was observed in female compared to male patients, in both study groups (p < 0.05). The results suggest negative linear correlation between bilirubin and UA levels and disease duration, EDSS and MRI in CIS (p < 0.01), with the same correlation between bilirubin and UA levels and disease duration in RRMS patients (p < 0.01). There was also significant correlation between bilirubin level and MRI findings and UA levels and EDSS in RRMS patients (p < 0.01). The obtained results point to the importance of endogenous antioxidants in the outbreak and course of neuroinflammation. This could be favorable for the new pathogenetically conditioned neuroinflammatory therapy concepts which do not initially rely only on immunomodulatory, but also on the antioxidative effects.

Dexamethasone decreases the spermidine and spermine concentrations and polyamine oxidase activity in rat thymus.

BACKGROUND: Glucocorticoids (GCs) exert a wide range of anti-inflammatory, immunosuppressive, and antineoplastic activities. The aim of our investigation was to elucidate the effect of dexamethasone, a synthetic GC, on polyamine metabolism in the rat thymus. METHODS: Male albino Wistar rats, weighing 180-230 g, were divided into two groups: control and experimental. The experimental group received dexamethasone intraperitoneally for 3 days, in a daily dose of 4 mg/animal. The last dose of the hormone was applied on the 3rd day, 1 h before killing. The control group received 0.9% NaCl instead of the hormone. The animals were killed by decapitation. The thymus was removed quickly and rinsed with ice-cold saline. Polyamines were extracted using butanol. The amount of polyamines was investigated by electrophoresis. For the estimation of polyamine oxidase (PAO) activity, 10% water homogenate was prepared. RESULTS: Our results suggested that dexamethasone supplementation of experimental animals for 3 days significantly decreased the spermine (Sp) and spermidine (Spd) levels in rat thymus tissue (Sp Control, 362.56±25.33 nmol/g wet weight; Sp Exp. Group, 313.01±21.16 nmol/g wet weight; Spd Control, 673.81±30.95 nmol/g wet weight; Spd Exp. Group, 410.21±17.26 nmol/g wet weight). PAO activity significantly decreased under hormone influence in comparison with the control group (PAO Control, 0.449±0.121 U/mg prot.; PAO Exp. Group, 0.312±0.096 U/mg prot.). CONCLUSIONS: The decrease in polyamine amounts in the rat thymus is not due to the change in PAO activity.

How the duration period of erythropoietin treatment influences the oxidative status of hemodialysis patients.

BACKGROUND: End-stage renal disease is a state of enhanced oxidative stress (OS) and hemodialysis (HD) and renal anemia further augment this disbalance. Anemia correction with erythropoietin (EPO) may improve oxidative status. However, there is no evidence of time dependent effects of EPO therapy on redox status of HD patients. OBJECTIVE: The aim of this study was to evaluate whether the duration of EPO treatment may affect OS parameters in uremic patients. PATIENTS AND METHODS: 104 HD patients and 29 healthy volunteers were included. Patients were divided into 3 groups according to the duration of EPO treatment. Forth group consisted of HD patients without EPO treatment. Plasma and erythrocyte malondialdehyde (MDA, MDA(rbc)), reactive carbonyl groups (RCG), plasma sulfhydryl (-SH) groups and total antioxidative capacity (TAC) levels were evaluated. RESULTS: HD patients both with and without EPO treatment, showed a significant increase in all oxidative parameters without significance between EPO treated and -untreated group. The decrease in MDA and MDA(rbc) levels coincided with the duration of EPO treatment. A negative correlation was observed between the duration of EPO treatment and serum MDA (r=-0.309, p=0.003). Increasing periods of EPO treatment were associated with decrease in RCG, without significance between EPO groups. Increase in TAC accompanied increasing durations of EPO treatment, with EPO treatment for more than 24 months causing the most striking changes (p<0.05). There were no significant differences in -SH levels between EPO subgroups. CONCLUSION: Our results suggest that long term administration of EPO attenuated the lipid peroxidation process and restored the levels of antioxidants.

Protective effects of glutathione and lipoic acid against cadmium-induced oxidative stress in rat's kidney.

Cadmium is a widespread, toxic industrial pollutant. The proximal tubule of the mammalian kidney is a major target of Cd-induced toxicity. We analyzed the effects of cadmium exposure on the model system of experimental animals, the thiobarbituric acid (TBA)-reactive substance (TBARS) level, and the activity of xanthine oxidase (XO) and catalase in kidney of rats, with and without glutathione and lipoic acid (LA). The experimental animals were classified into six groups, regarding cadmium, glutathione, and LA intake. The concentration of TBARSs in the homogenate was determined by spectrophotometric method according to Nabavi et al. The specific activity of XO was determined spectrophotometrically by the method of Aygul et al. Catalase activity in tissues was determined by spectrophotometric method according to Nabavi et al. The increased level of TBARS and the increased activity of XO in kidney tissue in cadmium poisoning are statistically significant compared to control (p < 0.001). Glutathione and LA applied along with cadmium lowered TBARS concentration and reduced XO activity (p < 0.001). Catalase activity in the kidney tissue was increased in the group, which was administered cadmium (p < 0.001). In conclusion, glutathione and LA, as physiological antioxidants applied with cadmium, have reduced the level of lipid peroxide and the activity of XO, and can be used as protectors in conditions of cadmium poisoning.

Association of vitamin D receptor genetic variants with bone mineral density and inflammatory markers in rheumatoid arthritis.

BACKGROUND AND AIMS: Vitamin D receptor (VDR) genetic variants are considered to have a role in the pathogenesis of rheumatoid arthritis (RA). This study examines an association of FokI, BsmI, ApaI and TaqI with RA, as well as with bone mineral density (RA with normal bone mineral density, RA-NBMD; RA with associated osteopenia, RA-OSTP; and RA with associated osteoporosis, RA-OP) and inflammatory markers. MATERIALS AND METHODS: VDR genetic variants were tested in 248 subjects using the PCR-RFLP method. RESULTS: Significant differences were observed in the distribution of FokI genotypes between RA patients (p < 0.001), or subgroups (RA-NBMD, RA-OSTP, RA-OP) (p = 0.035, p = 0.02, p < 0.001, respectively) and controls. Prevalence of FokI f allele was significantly higher in RA group (p < 0.001) and subgroups (p = 0.003, p = 0.021, p < 0.001, respectively) compared to controls. An increased susceptibility to RA-OSTP was revealed in BsmI/ApaI Ba (AC) haplotype carriers (p = 0.012). A significantly higher erythrocyte sedimentation rate values were obtained in FokI FF compared to Ff + ff carriers (54.57 ± 23.73 vs. 22.83 ± 12.42; p < 0.001) within the RA-NBMD subgroup. CONCLUSION: The results of the study indicate an association of RA with FokI genetic variant and increased susceptibility to RA in f allele carriers, as well as to RA-OSTP in BsmI/ApaI Ba (AC) haplotype carriers.

Effect of L-arginine on metabolism of polyamines in rat's brain with extrahepatic cholestasis.

Cholestatic encephalopathy results from accumulation of unconjugated bilirubin and hydrophobic bile acids in the brain. The aim of this study was to determine disturbances of polyamine metabolism in the brains of rats with experimental extrahepatic cholestasis and the effects of L-arginine administration. Wister rats were divided into groups: I: sham-operated, II: rats treated with L-arginine, III: animals with bile-duct ligation (BDL), and IV: cholestatic-BDL rats treated with L-arginine. Increased plasma gamma-glutamyltransferase and alkaline phosphatase activity and increased bile-acids and bilirubin levels in BDL rats were reduced by administration of L-arginine (P < 0.001). Cholestasis increased the brain's putrescine (P < 0.001) and decreased spermidine and spermine concentration (P < 0.05). The activity of polyamine oxidase was increased (P < 0.001) and diamine oxidase was decreased (P < 0.001) in the brains of BDL rats. Cholestasis increased the activity of arginase (P < 0.05) and decreased the level of citrulline (P < 0.001). Administration of L-arginine in BDL rats prevents metabolic disorders of polyamines and establishes a neuroprotective role in the brain during cholestasis.

Etanercept reduces matrix metalloproteinase-9 level in children with polyarticular juvenile idiopathic arthritis and TNF-alpha-308GG genotype.

Genetic contribution of tumor necrosis factor polymorphism (TNF-alpha-308G/A) in patients with juvenile idiopathic arthritis (JIA) on response to TNF blocking agents, as well as matrix metalloproteinase-9 (MMP-9) production, is not yet well established. We have investigated whether the TNF-alpha-308G/A polymorphism can influence MMP-9 level and clinical response to etanercept (TNF receptor II-Fc fusion protein) in JIA patients, after 1 year of treatment. A total of 66 patients with polyarticular JIA and 65 healthy children were screened for the polymorphism using the polymerase chain reaction-restriction fragment length polymorphism method. JIA patients donated paired blood samples prior to and 12 months after etanercept therapy. Plasma MMP-9 level was determined using an enzyme-linked immunosorbent assay kit. Clinical assessment was performed according to ACR Pedi 50 improvement criteria. The frequency of the A allele was significantly higher in JIA patients compared to controls (39% vs. 26%, P = 0.026). Patients with the -308GG genotype achieved an ACR Pedi 50 response significantly more frequently than those with the -308AA genotype (P = 0.035). MMP-9 level in patients with the genotype -308GG was significantly decreased after 1 year of treatment with etanercept compared to the value from before (P = 0.036). On the other hand, there was a decrease of MMP-9 levels after treatment, but not statistically significant in patients with the genotypes -308GA/AA. We conclude that etanercept reduces MMP-9 level in children with polyarticular JIA and TNF-alpha-308GG genotype. Our results correlate with findings that the -308A allele is associated with a lower response to etanercept treatment.

Thymus as a target tissue of glucocorticoid action: what are the consequences of glucocorticoids thymectomy?

Glucocorticoids represent the most powerful endogenous anti-inflammatory and immunosuppressive effectors, interfering with virtually every step of immunoinflammatory responses. Glucocorticoids are often the most effective therapy in the prevention or suppression of inflammation and other immunologically mediated processes, but their use is limited by systemic side effects induced by the over-production of reactive oxygen species, causing dysregulation of physiological processes. The thymus is an organ with both endocrine and immune functions. Glucocorticoids induce thymocyte apoptosis, causing a profound reduction in thymic mass and volume and inducing hormonal thymectomy. The clinical aspects of glucocorticoid thymectomy are not under enough investigation. These unwanted systemic side effects may be the consequence of prolonged therapeutic application of glucocorticoids and prolonged or chronic activation of the hypothalamic-pituitary adrenal axis, which may lead to increased and prolonged secretion of glucocorticoids. This review will discuss the metabolic effects of glucocorticoids in the context of thymic physiology asthe primary sex hormone-responsive organ.

Vitamin D receptor gene polymorphism influences lipid profile in patients with juvenile idiopathic arthritis.

Vitamin D receptor (VDR) gene FokI (rs2228570) polymorphism was postulated to influence outcome of several inflammatory diseases. The aim of this study was to evaluate the influence of rs2228570 polymorphism on lipid profile and on outcome in patients with juvenile idiopathic arthritis (JIA) treated with etanercept. A total of 153 subjects (62 JIA patients and 91 controls) were screened for the rs2228570 using the PCR-RFLP method. Lipid profile (cholesterol, triacylglycerol, HDL-C, and LDL-C) was determined using standard biochemical analysis in controls, while in JIA patients, it was determined prior to and 12 months after anti-TNF (etanercept) therapy. Clinical outcome was assessed using the JIA-American College of Rheumatology (ACR) response criteria. There were significant differences in the distribution of genotypes (p = 0.024) and alleles (p = 0.006; OR = 2.222, 95% CI 1.136-4.348) of the rs2228570 between patients and controls. Etanercept treatment significantly increased HDL-C levels (p = 0.006) in JIA patients with FF genotype in comparison to baseline values. No significant differences were seen in JIA-ACR 30/50/70 responses at month 12 between FF and Ff/ff genotype carriers. This is the first study to demonstrate the protective effect of the VDR FokI FF genotype on lipid profile in JIA patients treated with etanercept. However, this has to be confirmed in a larger cohort of patients.

The predictive value of Klotho polymorphism, in addition to classical markers of CKD-MBD, for left ventricular hypertrophy in haemodialysis patients.

PURPOSE: Cardiovascular events are the major reasons for mortality in haemodialysis patients. Fibroblast growth factor 23 (FGF23), Klotho protein and G-395A Klotho gene polymorphism have been associated with effects on the cardiovascular system. Our study investigates the interrelationship between Klotho protein gene variations, mineral-bone metabolism and left ventricular hypertrophy in patients undergoing chronic haemodialysis programme. MATERIALS AND METHODS: Patients (n = 142) were genotyped for G-395A Klotho gene. Components of mineral-bone metabolism, classical and non-classical (FGF23, Klotho and vitamin D) as well as echocardiographic examination were determined. Predictive models were designed to determine the significance of Klotho gene variations and mineral-bone metabolism components for left ventricle hypertrophy (LVH). RESULTS: A-allele carriers were longer on haemodialysis (p = 0.033), and had higher phosphorus levels (p = 0.016) while the level of Klotho protein was significantly lower (p = 0.001) compared to non-A-allele carriers. The best gains were achieved upon addition of allele A, and all three new markers; the AUC made significant improvement from 0.596 to 0.806 (p < 0.001), and improved net reclassification for 82.1% (95% CI 42.9-121.3%). CONCLUSIONS: The genetic background of A-allele carriers of the G-395A Klotho gene polymorphism increases the susceptibility patients to haemodialysis. A-allele carriers are at a higher risk for the development of cardiovascular complications. The addition of non-classical to classical mineral metabolism components improves prediction power to LVH.

Melatonin reduces oxidative stress induced by chronic exposure of microwave radiation from mobile phones in rat brain.

PURPOSE: The aim of the study was to evaluate the intensity of oxidative stress in the brain of animals chronically exposed to mobile phones and potential protective effects of melatonin in reducing oxidative stress and brain injury. MATERIALS AND METHODS: Experiments were performed on Wistar rats exposed to microwave radiation during 20, 40 and 60 days. Four groups were formed: I group (control)- animals treated by saline, intraperitoneally (i.p.) applied daily during follow up, II group (Mel)- rats treated daily with melatonin (2 mg kg(-1) body weight i.p.), III group (MWs)- microwave exposed rats, IV group (MWs + Mel)- MWs exposed rats treated with melatonin (2 mg kg(-1) body weight i.p.). The microwave radiation was produced by a mobile test phone (SAR = 0.043-0.135 W/kg). RESULTS: A significant increase in the brain tissue malondialdehyde (MDA) and carbonyl group concentration was registered during exposure. Decreased activity of catalase (CAT) and increased activity of xanthine oxidase (XO) remained after 40 and 60 days of exposure to mobile phones. Melatonin treatment significantly prevented the increase in the MDA content and XO activity in the brain tissue after 40 days of exposure while it was unable to prevent the decrease of CAT activity and increase of carbonyl group contents. CONCLUSION: We demonstrated two important findings; that mobile phones caused oxidative damage biochemically by increasing the levels of MDA, carbonyl groups, XO activity and decreasing CAT activity; and that treatment with the melatonin significantly prevented oxidative damage in the brain.

Oral supplementation with melatonin reduces oxidative damage and concentrations of inducible nitric oxide synthase, VEGF and matrix metalloproteinase 9 in the retina of rats with streptozotocin/nicotinamide induced pre-diabetes.

Hyperglycemia mediated oxidative stress and pro-angiogenic molecules such as vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP9) are considered important for diabetic retinopathy onset and progression. Melatonin is a pineal hormone that regulates circadian and seasonal rhythms and most likely is involved in regulating glucose metabolism. We aimed to evaluate the potential benefit of melatonin supplementation to the pre-diabetic retina by assessing melatonin effects on lipid peroxidation (thiobarbituric acid reactive substances, TBARS), protein oxidation (advanced oxidation protein products, AOPP) and concentrations of inducible nitric oxide synthase (iNOS), VEGF and MMP9 in the retina of rats with pre-diabetes. Pre-diabetes was induced by streptozotocin (45 mg/kg, i.p.) following nicotinamide injection (110 mg/kg, i.p.). Beside mild hyperglycemia, lower serum insulin, increased fructosamine and lower HDL cholesterol, the present study demonstrated decreased serum melatonin in pre-diabetic rats, as well as, increased concentration of retinal TBARS, AOPP, iNOS, VEGF, and MMP9. Oral supplementation with melatonin (85 µg/animal/day) caused melatonin and HDL cholesterol levels to rise in treated rats and reduced levels of fasting serum glucose and fructosamine. It also affected serum insulin and quantitative insulin sensitivity check index (QUICKI) in treated groups but had no significant effect on non-fasting glucose. Finally, supplementation with melatonin reduced concentrations of TBARS, AOPP, iNOS, VEGF, and MMP9 in significant level, thereby exerting an overall positive effect on oxidative stress and pro-angiogenic signaling in the pre-diabetic retina. Thus, oral melatonin might be considered in an early treatment or in the prevention of retinal changes associated with pre-diabetes.

Protective effect of interferon-alpha on the DNA- and RNA-degrading pathway in anti-Fas-antibody induced apoptosis.

AIM: Fas membrane-associated polypeptide antigen is a receptor molecule responsible for apoptosis-mediated signals. In animal models of acute viral hepatitis, apoptosis of hepatocytes is mediated by Fas-death receptors; therefore, the aim of this study was to evaluate the effect of interferon (IFN)-alpha on apoptotic markers and nuclease activity against different coding and non-coding single and double stranded RNAs during Fas-induced liver apoptosis. METHODS: An in vivo experiment was performed with simultaneous administration of anti-Fas (CD95) antibodies and IFN-alpha, and an in vitro experiment was performed in hepatocyte cultures treated with anti-Fas antibodies and IFN-alpha. RESULTS: Detection of apoptosis using Annexin V-FITC/propidium iodide, Bcl-2 and Bax expression in hepatocyte cultures confirmed the appearance of early apoptotic events and progression toward late apoptosis after anti-Fas antibody treatment. IFN-alpha had a tendency to retard the apoptosis process in Fas-induced apoptosis by increasing the number of viable cells and decreasing the number of cells in late apoptosis, by increasing the percentage of Bcl-2 positive cells, by decreasing the percentage of Bax positive cells, and by decreasing the nuclease activity compared to the anti-Fas antibody treated group. Total DNA and RNA concentration was much reduced in the Fas group and DNA fragmentation assay provided evidence for increased DNA degradation. Enhanced nuclease activity against DNA, rRNA, poly(A), poly(C), poly(U), poly(I:C), and poly(A:U) was manifested in the anti-Fas antibody treated group, except for the inhibitory-bound alkaline RNase. CONCLUSIONS: The results demonstrate that the RNA-degrading pathway in Fas-induced apoptosis can accelerate the liberation of the latent enzyme from the inhibitor complex. IFN-alpha prevented enormous, Fas-ligand induced degradation of all the substrates used in this experimental study, most probably due to similarities in the signal transduction pathways. Investigations of death receptor-induced apoptosis may lead to novel treatment combinations for patients with acute or chronic liver diseases.