Inonu University

Extracellular matrix (ECM) is a complex cellular environment consisting of proteins, proteoglycans, and other soluble molecules. ECM provides structural support to mammalian cells and a regulatory milieu with a variety of important cell functions, including assembling cells into various tissues and organs, regulating growth and cell-cell communication. Developing a tailored in vitro cell culture environment that mimics the intricate and organized nanoscale meshwork of native ECM is desirable. Recent studies have shown the potential of hydrogels to mimic native ECM. Such an engineered native-like ECM is more likely to provide cells with rational cues for diagnostic and therapeutic studies. The research for novel biomaterials has led to an extension of the scope and techniques used to fabricate biomimetic hydrogel scaffolds for tissue engineering and regenerative medicine applications. In this article, we detail the progress of the current state-of-the-art engineering methods to create cell-encapsulating hydrogel tissue constructs as well as their applications in in vitro models in biomedicine.

Researchers have recently focused on the advancement of new materials from biorenewable and sustainable sources because of great concerns about the environment, waste accumulation and destruction, and the inevitable depletion of fossil resources. Biorenewable materials have been extensively used as a matrix or reinforcement in many applications. In the development of innovative methods and materials, composites offer important advantages because of their excellent properties such as ease of fabrication, higher mechanical properties, high thermal stability, and many more. Especially, nanocomposites (obtained by using biorenewable sources) have significant advantages when compared to conventional composites. Nanocomposites have been utilized in many applications including food, biomedical, electroanalysis, energy storage, wastewater treatment, automotive, etc. This comprehensive review provides chemistry, structures, advanced applications, and recent developments about nanocomposites obtained from biorenewable sources.

The purpose of this registry study was to provide an overview of trends and results of liver transplantation (LT) in Europe from 1968 to 2016. These data on LT were collected prospectively from 169 centers from 32 countries, in the European Liver Transplant Registry (ELTR) beginning in 1968. This overview provides epidemiological data, as well as information on evolution of techniques, and outcomes in LT in Europe over more than five decades; something that cannot be obtained from only a single center experience.

It has long been known that the major irreversible toxicity of aminoglycosides is ototoxicity. Among them, streptomycin and gentamicin are primarily vestibulotoxic, whereas amikacin, neomycin, dihydrosterptomycin, and kanamicin are primarily cochleotoxic. Cochlear damage can produce permanent hearing loss, and damage to the vestibular apparatus results in dizziness, ataxia, and/or nystagmus. Aminoglycosides appear to generate free radicals within the inner ear, with subsequent permanent damage to sensory cells and neurons, resulting in permanent hearing loss. Two mutations in the mitochondrial 12S ribosomal RNA gene have been previously reported to predispose carriers to aminoglycoside-induced ototoxicity. As aminoglycosides are indispensable agents both in the treatment of infections and Meniere's disease, a great effort has been made to develop strategies to prevent aminoglycoside ototoxicity. Anti-free radical agents, such as salicylate, have been shown to attenuate the ototoxic effects of aminoglycosides. In this paper, incidence, predisposition, mechanism, and prevention of aminoglycoside-induced ototoxicity is discussed in the light of literature data.

We analyzed a global collection of Mycobacterium tuberculosis strains using 212 single nucleotide polymorphism (SNP) markers. SNP nucleotide diversity was high (average across all SNPs, 0.19), and 96% of the SNP locus pairs were in complete linkage disequilibrium. Cluster analyses identified six deeply branching, phylogenetically distinct SNP cluster groups (SCGs) and five subgroups. The SCGs were strongly associated with the geographical origin of the M. tuberculosis samples and the birthplace of the human hosts. The most ancestral cluster (SCG-1) predominated in patients from the Indian subcontinent, while SCG-1 and another ancestral cluster (SCG-2) predominated in patients from East Asia, suggesting that M. tuberculosis first arose in the Indian subcontinent and spread worldwide through East Asia. Restricted SCG diversity and the prevalence of less ancestral SCGs in indigenous populations in Uganda and Mexico suggested a more recent introduction of M. tuberculosis into these regions. The East African Indian and Beijing spoligotypes were concordant with SCG-1 and SCG-2, respectively; X and Central Asian spoligotypes were also associated with one SCG or subgroup combination. Other clades had less consistent associations with SCGs. Mycobacterial interspersed repetitive unit (MIRU) analysis provided less robust phylogenetic information, and only 6 of the 12 MIRU microsatellite loci were highly differentiated between SCGs as measured by GST. Finally, an algorithm was devised to identify two minimal sets of either 45 or 6 SNPs that could be used in future investigations to enable global collaborations for studies on evolution, strain differentiation, and biological differences of M. tuberculosis.

This technical note presents a solution to the problem of stabilizing a given fractional-order system with time delay using fractional-order Pl <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">lambda</sup> D <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mu</sup> controllers. It is based on determining a set of global stability regions in the (k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> , K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> , K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</sub> )-space corresponding to the fractional orders lambda and mu in the range of (0, 2) and then choosing the biggest global stability region in this set. This method can be also used to find the set of stabilizing controllers that guarantees prespecified gain and phase margin requirements. The algorithm is simple and has reliable result which is illustrated by an example, and, hence, is practically useful in the analysis and design of fractional-order control systems.

PURPOSE: To compare the effectiveness of intraarticular (IA) multiple and single platelet-rich plasma (PRP) injections as well as hyaluronic acid (HA) injections in different stages of osteoarthritis (OA) of the knee. METHODS: A total of 162 patients with different stages of knee OA were randomly divided into four groups receiving 3 IA doses of PRP, one dose of PRP, one dose of HA or a saline injection (control). Then, each group was subdivided into two groups: early OA (Kellgren-Lawrence grade 0 with cartilage degeneration or grade I-III) and advanced OA (Kellgren-Lawrence grade IV). The patients were evaluated before the injection and at the 6-month follow-ups using the EuroQol visual analogue scale (EQ-VAS) and International Knee Documentation Committee (IKDC) subjective scores. Adverse events and patient satisfaction were recorded. RESULTS: There was a statistically significant improvement in the IKDC and EQ-VAS scores in all the treatment groups compared with the control group. The knee scores of patients treated with three PRP injections were significantly better than those patients of the other groups. There was no significant difference in the scores of patients injected with one dose of PRP or HA. In the early OA subgroups, significantly better clinical results were achieved in the patients treated with three PRP injections, but there was no significant difference in the clinical results of patients with advanced OA among the treatment groups. CONCLUSION: The clinical results of this study suggest IA PRP and HA treatment for all stages of knee OA. For patients with early OA, multiple (3) PRP injections are useful in achieving better clinical results. For patients with advanced OA, multiple injections do not significantly improve the results of patients in any group. LEVEL OF EVIDENCE: I.

Recent data from several reports indicate that free radicals are involved in the biochemical mechanisms underlying neuropsychiatric disorders in human. The results of several reports suggest that lower antioxidant defences against lipid peroxidation exist in patients with depression and that there is a therapeutic benefit from antioxidant supplementation in unstable manic-depressive patients. We investigated the antioxidant enzyme status and the indices of oxidative stress and lipid peroxidation end products in erythrocytes from patients with affective disorder. For this purpose, we measured superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities, as well as malondialdehyde (MDA) and nitric oxide (NO) levels in patients with affective disorders (n=30) in both pre- and post-treatment periods, and in a control group (n=21). CAT activities were significantly decreased in both pre-, and post-treatment periods in patients compared to the control group. GSH-Px activity in the pre-treatment period in the patients was significantly lower than both post-treatment patient and control groups. MDA levels were increased in both pre-, and post-treatment patient groups compared to the control group. NO level was lower in the pre-treatment patient group than in the control group. There were statistically significant correlations between SOD and MDA, and SOD and NO in the pre-treatment patient and control groups. Because the overall study sample was small, and the post-treatment patient group was even smaller, it can tentatively be suggested that the antioxidant system is impaired during a mood episode in patients with affective disorders, normalizing at the end of the episode.

PURPOSE: This study was conducted to evaluate nursing students' views on the COVİD-19 pandemic and their perceived stress levels. DESIGN AND METHODS: A cross-sectional design was used to carry out this study. The research was conducted between April and May 2020 with 662 nursing students. Data were collected by an information form developed for the study and the Perceived Stress Scale (PSS). FINDINGS: The average score on the PSS was 31.69 ± 6.91, indicating that the students had a moderate level of stress. Significant differences in PSS score were found in terms of age and sex (P < .001 and P < .001, respectively). PRACTICE IMPLICATIONS: Results of this study indicated that age, sex, and some variables related to the pandemic process affect perceived stress levels of nursing students.

Factors determining in-hospital mortality and long-term survival of patients hospitalised with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are not precisely understood. The aim of the present study was to assess the parameters related to in-hospital mortality and long-term survival after hospitalisation of patients with AECOPD. Clinical and epidemiological parameters on admission in 205 consecutive patients hospitalised with AECOPD were prospectively assessed. Patients were followed-up for 3 yrs. Factors determining short- and long-term mortality were analysed. In total, 17 patients (8.3%) died in hospital. In-hospital mortality was significantly associated with lower arterial oxygen tension (P(a,O2)), higher carbon dioxide arterial tension, lower arterial oxygen saturation and longer hospital stay. The overall 6-month mortality rate was 24%, with 1-, 2- and 3-yr mortality rates of 33%, 39% and 49%, respectively. Cox regression analysis revealed that long-term mortality was associated with longer disease duration (relative risk (RR) = 1.158), lower albumin (RR = 0.411), lower P(a,O2) (RR = 0.871) and lower body mass index (RR = 0.830). When the model was run for the time elapsed since first hospitalisation, it also appeared as statistically significant (RR = 1.195). These findings show that patients hospitalised with acute exacerbations of chronic obstructive pulmonary disease have poor short- and long-term survival. Prediction of survival status may be enhanced by considering arterial oxygen tension, albumin, body mass index, disease duration and time elapsed since the first hospitalisation.

The influence of different levels of inulin on the quality of fat‐free yogurt production was investigated. Inulin was added to milk containing 0.1% of milk fat to give inulin levels of 1, 2 and 3%. The experimental yogurts were compared with control yogurt produced from whole milk. The total solids content of milk was standardized to 14% by adding skim milk powder to the experimental yogurt. The chemical composition, pH, titratable acidity, whey separation, consistency, acetaldehyde and volatile fatty acidity contents were determined in the experimental yogurts after 1, 7 and 15 days. Sensory properties of the yogurts were evaluated during storage. The addition of inulin at more than 1% increased whey separation and consistency. Acetaldehyde, pH and titratable acidity were not influenced by addition of inulin. Tyrosine and volatile fatty acidity levels were negatively affected by inulin addition. With respect to the organoleptic quality of yogurt, inulin addition caused a decrease in organoleptic scores: the control yogurt had the highest score, and the lowest score was obtained in yogurt samples containing 3% of inulin. Overall, the yogurt containing 1% of inulin was similar in quality characteristics to control yogurt made with whole milk.

In Brief We compared the sedative, hemodynamic, and respiratory effects of dexmedetomidine and propofol in children undergoing magnetic resonance imaging procedures. Sixty children were randomly distributed into two groups: The dexmedetomidine (D) group received 1 μg/kg initial dose followed by continuous infusion of 0.5 μg · kg−1 · h−1 and a propofol group (P) received 3 mg/kg initial dose followed by a continuous infusion of 100 μg · kg−1 · min−1. Inadequate sedation was defined as difficulty in completing the procedure because of the child's movement during magnetic resonance imaging. Mean arterial pressure (MAP), heart rate, peripheral oxygen saturation, and respiratory rate (RR) were recorded during the study. The onset of sedation, recovery, and discharge time were significantly shorter in group P than in group D. MAP, heart rate, and RR decreased during sedation from the baseline values in both groups. MAP and RR were significantly lower in group P than in group D during sedation. Desaturation was observed in four children of group P. Dexmedetomidine and propofol provided adequate sedation in most of the children. We conclude that although propofol provided faster anesthetic induction and recovery times, it caused hypotension and desaturation. Thus, dexmedetomidine could be an alternative reliable sedative drug to propofol in selected patients. IMPLICATIONS: We evaluated the sedative, hemodynamic, and respiratory effects of dexmedetomidine and propofol in children undergoing magnetic resonance imaging examination. Although propofol provided faster induction and recovery times, it caused hypotension and desaturation. Thus, dexmedetomidine could be an alternative reliable sedative drug to propofol in selected patients.

Five different rose hip (Rosa L.) species including Rosa canina, Rosa dumalis, Rosa gallica, Rosa dumalis subsp.boissieri and Rosa hirtissima grown in Turkey are studied. Phenolic compounds, organic acids, sugar and volatile compounds of five different species of rose hips are studied. Total phenolic contents of the rose hip fruits were significantly influenced by species and the levels of total flavonoid and tartaric esters were almost identical in the samples. Antioxidant activities and antiradical scavenging capacities of the extracts were high levels in all rose hip species. It is noticeable that organic acid and sugar contents of the fruits were highly dependence of species and the high levels of ascorbic acid were characteristic. In total, eighteen different phenolic compounds were identified in rose hip species by RP-HPLC-DAD method and, in particular, R. dumalis subsp. boissiericontained different phenolic compounds. Gallic acid, catechin, procyanidin-B2 and hydroxycinnamic acid derivatives (chlorogenic, t-caffeic, p-coumaric, ferrulic and sinapic acids) were principal for all rose hip species. A total of 52 volatile compounds were identified in rose hip species by SPME/GC-MS and it was characterized by abundance of alcohols and aldehydes with also some monoterpenes and sesquiterpenes.

BACKGROUND: Behçet's disease (BD) is a systemic inflammatory disease with unpredictable exacerbations and remissions. The natural course of BD is not fully known. OBJECTIVES: We aimed retrospectively to determine the occurrence of the symptoms in chronological order. We also evaluated the influence of the treatment and follow-up on the clinical severity and tried to identify the factors determining severe organ involvement. METHODS: Six hundred and sixty-one patients were involved in this multicentre study. The symptoms of the disease were recorded retrospectively in the time order of the manifestations in each patient. RESULTS: Oral ulcers were the most common manifestation (100%), followed by genital ulcers (85.3%), papulopustular lesions (55.4%), erythema nodosum (44.2%), skin pathergy reaction (37.8%), and articular (33.4%) and ocular involvement (29.2%). Oral ulcers were the most common onset manifestation (88.7%). The mean +/- SD duration between the onset symptom and the fulfilment of diagnostic criteria was calculated to be 4.3 +/- 5.7 years. The clinical severity score was significantly increased in the noncompliant treatment group compared with the compliant group with the passage of time (P < 0.001). The frequency of ocular involvement and genital ulcers was significantly higher in patients whose disease onset was at < 40 years. Genital ulcers, ocular involvement, papulopustular lesions, thrombophlebitis and skin pathergy reaction were found to be significantly more frequent in males. CONCLUSIONS: Mucocutaneous lesions are the hallmarks of the disease, and especially oral ulcers precede other manifestations. The increase in clinical severity score is more pronounced in patients without regular treatment and follow-up. Male sex and a younger age at onset are associated with more severe disease.

The influence of milk protein-based ingredients on the textural characteristics, sensory properties, and microstructure of probiotic yogurt during a refrigerated storage period of 28 d was studied. Milk was fortified with 2% (wt/vol) skim milk powder as control, 2% (wt/vol) sodium calcium caseinate (SCaCN), 2% (wt/vol) whey protein concentrate (WPC) or a blend of 1% (wt/vol) SCaCN and 1% (wt/vol) WPC. A commercial yogurt starter culture and Bifidobacterium lactis Bb12 as probiotic bacteria were used for the production. The fortification with SCaCN improved the firmness and adhesiveness. Higher values of viscosity were also obtained in probiotic yogurts with SCaCN during storage. However, WPC enhanced water-holding capacity more than the caseinate. Addition of SCaCN resulted in a coarse, smooth, and more compact protein network; however, WPC gave finer and bunched structures in the scanning electron microscopy micrographs. The use of SCaCN decreased texture scores in probiotic yogurt; probably due to the lower water-holding capacity and higher syneresis values in the caseinate-added yogurt sample. Therefore, the textural characteristics of probiotic yogurts improved depending on the ingredient variety.

The aim of this study was to investigate the effectiveness of curcumin, β-myrcene (myrcene) and 1,8-cineole (cineole) on antioxidant defense system in rats given a persistent environmental pollutant (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD). Rats (n = 112) were divided randomly into 8 equal groups. One group was kept as control and given corn oil as carrier. TCDD was orally administered at the dose of 2 μg/kg/week. Curcumin, myrcene and cineole were orally administered at the doses of 100 mg/kg/day, 200 mg/kg/day and 100 mg/kg/ day, respectively, by gavages dissolved in corn oil with and without TCDD. The liver samples were taken from half of all rats on day 30 and from the remaining half on day 60 for the determination of thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), catalase (CAT), glutathione peroxidase (GSH-Px) and CuZn-SOD levels by spectrophotometric method. The results indicated that although TCDD significantly (p ≤ 0.01) increased formation of TBARS, it caused a significant decline in the levels of GSH, CAT, GSH-Px and CuZn-SOD in rats. In contrast, curcumin, myrcene and cineole significantly increased GSH, CAT, GSH-Px and CuZn-SOD levels but decreased formation of TBARS. Additionally, the antioxidative effects of curcumin, myrcene and cineole were increased at day 60 compared to day 30. In the TCDD groups given curcumin, myrcene and cineole, oxidative stress decreased by time. In conclusion, curcumin, myrcene and cineole showed antioxidant activity and eliminated TCDD-induced oxidative stress in rats in a time-dependent manner.

This is the first systematic account of the main results in the theory of lightlike submanifolds of semi-Riemannian manifolds which have a geometric structure, such as almost Hermitian, almost contact metric or quaternion Kähler. Using these structures, the book presents interesting classes of submanifolds whose geometry is very rich. The book also includes hypersurfaces of semi-Riemannian manifolds, their use in general relativity and Osserman geometry, half-lightlike submanifolds of semi-Riemannian manifolds, lightlike submersions, screen conformal submersions, and their applications in harmonic maps. Basic constructions and definitions are presented as preliminary background in every chapter. The presentation explores applications and suggests several open questions. This self-contained monograph provides up-to-date research in lightlike geometry and is intended for graduate students and researchers just entering this field.

AIM: Behçet's disease (BD) is asystemic immunoinflammatory disorder and the aetiopathogenesis is to be specified. Cytokines play a role in immune response and in many inflammatory diseases. The aim of this case-control study is to investigate serum pro-inflammatory cytokine tumour necrosis factor (TNF)-alpha, interleukin-1beta (IL-1beta), soluble IL-2 receptor (sIL-2R), IL-6, and chemokine IL-8 levels in patients with BD. We also determined the end product of lipid peroxidation (malondialdehyde (MDA)) in BD patients as an index for oxidative stress. METHODS: A total of 37 patients (19 men, 18 women) with BD (active, n = 17; inactive, n = 20) and 20 age-matched and sex-matched healthy control subjects (11 men, nine women) included in this cross-sectional, blinded study. Serum TNF-alpha, IL-1beta, sIL-2R, IL-6 and IL-8 levels were determined by a spectrophotometer technique using the immulite chemiluminescent immunometric assay. Lipid peroxidation was evaluated by Wasowicz et aL The levels of cytokines and lipid peroxidation in the active period were compared with the inactive period of the disease. Results are expressed as mean +/- standard error. RESULTS: IL-1beta levels were below the detection limits of the assay (< 5 pg/ml) in all samples. Mean levels of MDA (8.1+/-0.7 micromol/l), sIL-2R (800+/-38 U/ml), IL-6 (12.6+/-1.1 pg/ml), IL-8 (7.2+/-0.4 pg/ml), and TNF-alpha (7.9+/-0.5 pg/ml) in active BD patients were significantly higher than those in inactive patients (4.3+/-0.5 micromol/l, p < 0.01; 447+/-16 U/ml, p < 0.001; 8.3+/-0.6 pg/ml, p = 0.006; 5.3+/-0.1 pg/ml, p < 0.001; and 5.1 0.2 pg/ml, p < 0.001; respectively) or control subjects (2.1+/-0.2 micromol/l, p < 0.001; 446+/-20 U/ml, p < 0.001; 6.4+/-0.2 pg/ml, p < 0.001; 5.4+/-0.1 pg/ml, p < 0.001; and 4.7+/-0.1 pg/ml, p < 0.001, respectively). On the contrary, only the mean IL-6 level was significantly different between inactive BD and control subjects (p = 0.02). All acute phase reactants were significantly higher in active BD than in inactive period (for each, p < 0.01). CONCLUSIONS: High levels of sIL-2R, IL-6, IL-8 and TNF-alpha indicate the activation of immune system in BD. Serum sIL-2R, IL-6, IL-8 and TNF-alpha seem to be related to disease activity. Increased lipid peroxidation suggests oxidative stress in BD and therefore tissue damage in such patients. Amelioration of clinical manifestations would be envisaged by targeting these cytokines, chemokines and lipid peroxidation with pharmacological agents.

BACKGROUND: Chronic kidney disease (CKD) and immunosuppression, such as in renal transplantation (RT), stand as one of the established potential risk factors for severe coronavirus disease 2019 (COVID-19). Case morbidity and mortality rates for any type of infection have always been much higher in CKD, haemodialysis (HD) and RT patients than in the general population. A large study comparing COVID-19 outcome in moderate to advanced CKD (Stages 3-5), HD and RT patients with a control group of patients is still lacking. METHODS: We conducted a multicentre, retrospective, observational study, involving hospitalized adult patients with COVID-19 from 47 centres in Turkey. Patients with CKD Stages 3-5, chronic HD and RT were compared with patients who had COVID-19 but no kidney disease. Demographics, comorbidities, medications, laboratory tests, COVID-19 treatments and outcome [in-hospital mortality and combined in-hospital outcome mortality or admission to the intensive care unit (ICU)] were compared. RESULTS: A total of 1210 patients were included [median age, 61 (quartile 1-quartile 3 48-71) years, female 551 (45.5%)] composed of four groups: control (n = 450), HD (n = 390), RT (n = 81) and CKD (n = 289). The ICU admission rate was 266/1210 (22.0%). A total of 172/1210 (14.2%) patients died. The ICU admission and in-hospital mortality rates in the CKD group [114/289 (39.4%); 95% confidence interval (CI) 33.9-45.2; and 82/289 (28.4%); 95% CI 23.9-34.5)] were significantly higher than the other groups: HD = 99/390 (25.4%; 95% CI 21.3-29.9; P < 0.001) and 63/390 (16.2%; 95% CI 13.0-20.4; P < 0.001); RT = 17/81 (21.0%; 95% CI 13.2-30.8; P = 0.002) and 9/81 (11.1%; 95% CI 5.7-19.5; P = 0.001); and control = 36/450 (8.0%; 95% CI 5.8-10.8; P < 0.001) and 18/450 (4%; 95% CI 2.5-6.2; P < 0.001). Adjusted mortality and adjusted combined outcomes in CKD group and HD groups were significantly higher than the control group [hazard ratio (HR) (95% CI) CKD: 2.88 (1.52-5.44); P = 0.001; 2.44 (1.35-4.40); P = 0.003; HD: 2.32 (1.21-4.46); P = 0.011; 2.25 (1.23-4.12); P = 0.008), respectively], but these were not significantly different in the RT from in the control group [HR (95% CI) 1.89 (0.76-4.72); P = 0.169; 1.87 (0.81-4.28); P = 0.138, respectively]. CONCLUSIONS: Hospitalized COVID-19 patients with CKDs, including Stages 3-5 CKD, HD and RT, have significantly higher mortality than patients without kidney disease. Stages 3-5 CKD patients have an in-hospital mortality rate as much as HD patients, which may be in part because of similar age and comorbidity burden. We were unable to assess if RT patients were or were not at increased risk for in-hospital mortality because of the relatively small sample size of the RT patients in this study.

The number of reports on the effects induced by electromagnetic radiation (EMR) in various cellular systems is still increasing. Until now no satisfactory mechanism has been proposed to explain the biological effects of this radiation. Oxygen free radicals may play a role in mechanisms of adverse effects of EMR. This study was undertaken to investigate the influence of electromagnetic radiation of a digital GSM mobile telephone (900 MHz) on oxidant and antioxidant levels in rabbits. Adenosine deaminase, xanthine oxidase, catalase, myeloperoxidase, superoxide dismutase (SOD) and glutathione peroxidase activities as well as nitric oxide (NO) and malondialdehyde levels were measured in sera and brains of EMR-exposed and sham-exposed rabbits. Serum SOD activity increased, and serum NO levels decreased in EMR-exposed animals compared to the sham group. Other parameters were not changed in either group. This finding may indicate the possible role of increased oxidative stress in the pathophysiology of adverse effect of EMR. Decreased NO levels may also suggest a probable role of NO in the adverse effect.