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Diabetes and obesity are very common associated metabolic disorders that are linked to chronic inflammation. The development of insulin resistance is driven by multiple factors including an increase in levels of pro-inflammatory cytokines such as tumor necrosis factoralpha (TNF-a). This study aimed to explore the links between TNF-a -mediated inflammation, insulin sensitivity, and body weight gain in the rat model of type 2 diabetes mellitus (T2DM). The experiment was performed on 10 weeks old Wistar rats randomized into 2 groups. T2DM was induced by intraperitoneal injection of streptozotocin, administered 15 minutes after an intraperitoneal injection of nicotinamide. After 6 weeks, the animals were euthanized. Insulin and TNF-a were determined by using an enzyme-linked immunosorbent assay kit. Insulin sensitivity indices were calculated. The concentration of TNF-a was significantly higher in animals with T2DM when compared to controls (p < 0.001). Quantitative Insulin Sensitivity Check Index (QIUCKI) had significantly lower values in animals with T2DM when compared to controls (p < 0.001), whereas values calculated for homeostatic model assessment of insulin resistance (HOMA-IR) were significantly higher (p < 0.001). TNF-a correlated positively with HOMA-IR (r = 0.562, p < 0.01) and negatively with QIUCKI (r =-0.332, p < 0.05). Additionally, TNF-a correlated positively with specific rate of the body weight gain (r = 0.667, p < 0.01) in the observed period. The results suggest that an increase in circulating TNF-a concentration might be associated with an increase in body weight gain and reduced insulin sensitivity in rats with T2DM.

Skeletal muscle tissue is known to be susceptible to oxidative tissue damage that accompanies different disorders. Carbon tetrachloride (CCl4) is dangerous chemical that is used to mimic disorders, in experimental animals, related to reactive oxygen species induced tissue damage. It is well established that antioxidants, both natural and synthetic ones, are able to alleviate tissue damage caused by reactive oxygen species. The aim of the present study was to determine the effects of melatonin (MLT), a strong naturally occurring antioxidant, on changes in Wistar rat skeletal muscle catalase activity acutely induced by CCl4. Gastrocnemius muscle tissue, in which catalase activity was determined, was obtained from three groups of animals i.e. control (untreated), CCl4 treated and MLT and CCl4 group. The results revealed statistically significant decrease in muscle tissue catalase activity in rats exposed to CCl4, while in the group that received MLT and CCl4 this decrease was insignificant. The protective activity of MLT could be contributed to its different mechanisms since it is known to directly scavenge free radicals, increase tissue antioxidant capacity and to up-regulate antioxidant enzyme gene expression.

We aimed to evaluate whether two methionine-related compounds, S-adenosylmethionine (SAM), and selenomethionine (SM), could lessen liver damage induced by regurgitated bile in a model of rat bile duct ligation (BDL). Hepatoprotective potentials of S-adenosylmethionine and selenomethionine were estimated based on the changes of serum liver damage parameters (aminotransferases, alkaline phosphatase, gamma-glutamyltranspeptidase and lactate dehydrogenase activity, and bilirubin concentration), tissue oxidative [xanthine oxidase (XO) and catalase activity, thiobarbituric acid reactive substances (TBARS) levels] and inflammatory [tumor necrosis factor-alfa (TNF-α) concentration] parameters, and morphological liver tissue alterations that follow cholestasis. The treatment regimens proved themselves able to prevent significant liver damage induced by cholestasis. Both SAM and SM decreased XO activity and TBARS levels and increased catalase activity, while only SM significantly reduced TNF-α concentration. Morphological changes related to bile-induced liver damage were also found to be partially diminished by SAM and SM. In view of the mechanisms of action of the two tested methionine-derived compounds, one might say that SM predominantly acted as an antioxidant, while SAM exerted its activity by potentially modulating different gene expression and protein structures. It is also worth mentioning that this is the first study (to the best of our knowledge) that dealt with the effects of SM on BDL-induced liver injury in rats and of the findings that speak favorably of this powerful antioxidant.

Rat bile duct ligation (BDL) represents a useful method that mimics obstructive extrahepatic cholestasis, which is known to be a frequent disorder in humans. Polyamines (putrescine, spermidine, and spermine) are one of the key molecules regulating cell proliferation and differentiation. This work aimed to evaluate the potential beneficial properties of putrescine in rat BDL model by studying several biochemical parameters reflecting liver function and polyamine metabolism. Rats that were subjected to BDL were injected with putrescine (150 mg/kg) for 9 days, while in parallel another group with BDL remained untreated. Two control groups were included as well, sham-opened and putrescine-treated group. The following plasma parameters: ALT, AST, γ-GT, ALP, bilirubin, bile acids, as well as liver malondialdehyde and polyamine concentration and the activity of enzymes involved in polyamine metabolism were studied. After BDL, significant alterations in plasma biochemical parameters occurred, where a 9-day putrescine treatment significantly alleviated liver function deterioration. Putrescine also increased liver polyamines’ concentrations and polyamine and diamine oxidase activities in rats submitted to BDL. Our results demonstrated, for the first time, that putrescine plays an important role in preserving liver tissue function in rats with experimentally induced cholestasis.

Balkan endemic nephropathy (BEN) represents a chronic tubulointerstitial nephropathy which is followed by the progression of kidney fibrosis to end-stage kidney failure. The critical involvement of poisons in food (aristolochic acid (AA), ochratoxin, and heavy metals) and selenium deficiency are among nutritive factors which contribute to the pathogenesis of BEN, due to reactive oxygen species (ROS) liberation and/or decreased antioxidative defence system. The aim of the study is to distinguish a possible systemic and local origin of ROS through the measurement of xanthine oxidase (XO) activity in urine and plasma, along with the determination of the oxidative changes in lipids and proteins. The study included 50 patients with BEN and 38 control healthy subjects. We noted increased levels of both thiobarbituric acid-reactive substances (TBARS) and advanced oxidation protein products (AOPPs) in the plasma of patients with BEN, compared to the control group (p<0.001). The urinary levels of AOPPs were higher in patients with BEN in comparison to the control (p<0.001). The specific activity of XO was significantly lower in plasma and urine in BEN samples, compared to controls (p<0.005). Based on these results, we hypothesize that XO might not be considered a direct systemic or local contributor to ROS production in BEN, most probably because of the diminished kidney functional tissue mass and/or AA-induced changes in purine nucleotide conformation. The increased AOPP and TBARS level in both plasma and urine in BEN may predict ROS systemic liberation with toxic local effects.

Animal models demonstrating skeletal muscle (SM) disorders are rarely investigated, although these disorders accompany liver disorders and can occur during prolonged exercise/training. In cases of SM disorders exogenous antioxidants, such as melatonin, could help by generally improving tissues antioxidant capacities. We aimed to analyze the potential of melatonin in preventing biochemical and structural changes in rat biceps muscle (BM) occurring after an acute exposure to carbon tetrachloride (CCl4). Biceps muscles obtained from male Wistar rats belonging to different experimental groups were biochemically (determination of tissue MDA, total antioxidant capacity, GSH, CAT, SOD and GPx activities) and pathologically analyzed. Also, serum levels of potassium, LHD and CK were analyzed in all experimental animals. The obtained results were statically compared with those from vehicle-treated control group. The applied melatonin prevented potassium and intracellular enzyme leakage (CK and LDH) that was induced by CCl4, as well as an increase in tissue MDA. From a panel of determined oxidative stress parameters melatonin was able to statistically significantly prevent changes in total antioxidative capacity and in CAT, SOD and GPx activities induced by CCl4. Microscopic analysis of BM from the animals exposed to CCl4 revealed significant muscle fiber disorganization and massive inflammatory cell infiltration. All these changes were significantly ameliorated in the group that received melatonin prior to CCl4. Changes in serum and tissue biochemical parameters accompanied the observed pathological changes, which demonstrated a significant influence of melatonin in preventing skeletal muscle damage induced by CCl4. Keywords: Carbon tetrachloride, Melatonin, Skeletal muscles, Oxidative damage

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.

Aims The present study was designed to compare the ameliorating potential of pre- and post-treatments with melatonin, a potent natural antioxidant, in the carbon tetrachloride-induced rat liver damage model by tracking changes in enzymatic and non-enzymatic liver tissue defense parameters, as well as in the occurring pathohistological changes. Main methods Rats from two experimental groups were treated with melatonin before and after CCl4 administration, while the controls, negative and positive, received vehicle/melatonin and CCl4, respectively. Serum levels of transaminases, alkaline phosphates, γ-GT, bilirubin, and albumin, as well as a wide panel of oxidative stress-related parameters in liver tissue, were determined in all experimental animals. Liver tissue specimens were stained with hematoxylin and eosin and further evaluated for morphological changes. Key findings Both pre- and post-treatment with melatonin prevented a CCl4-induced increase in serum (ALT, AST, and γ-GT) and tissue (MDA and XO) liver damage markers and a decrease in the tissue total antioxidant capacity, in both enzymatic and non-enzymatic systems. The intensity of pathological changes, hepatocyte vacuolar degeneration, necrosis and inflammatory cell infiltration, was suppressed by the treatment with melatonin. Significance In conclusion, melatonin, especially as a post-intoxication treatment, attenuated CCl4-induced liver oxidative damage, increased liver antioxidant capacities and improved liver microscopic appearance. The results are of interest due to the great protective potential of melatonin that was even demonstrated to be stronger if applied after the tissue damage.

Objective: We evaluated the utility of preoperative midregional (MR) pro-adrenomedullin (proADM) and cardiac troponin T (TnT) for improved detection of patients at high risk for perioperative cardiac events and mortality after major noncardiac surgery. Subjects and Methods: This prospective, single-center, observational study enrolled 79 patients undergoing major noncardiac surgery. After initial clinical assessment (clinical history, physical examination, echocardiogram, blood tests, and chest X-ray), MR-proADM and high-sensitivity TnT (hsTnT) were measured within 48 h prior to surgery by immunoluminometric and electrochemiluminescence immunoassay. Patients were followed by the consulting physician until discharge or up to 14 days in the hospital after surgery. Perioperative cardiac events included myocardial infarction and development or aggravation of congestive heart failure. Data were compared between patients who developed target events and event-free patients. Results: Within 14 days of monitoring, 14 patients (17.72%) developed target events: 9 (11.39%) died and 5 (6.33%) developed cardiovascular events. The average age of the patients was 71.29 ± 6.62 years (range: 55–87). Sex, age, and hsTnT did not significantly differ between groups. MR- proADM concentration was higher in deceased patients (p = 0.01). The upper quartile of MR-proADM was associated with a fatal outcome (66.7 vs. 20.0%, p < 0.01) and with cardiovascular events (64.3 vs. 16.9%, p < 0.01). MR-proADM above the cutoff value (≥0.85) was associated with a fatal outcome (88.9 vs. 20.0%, p < 0.01) and cardiovascular events (71.4 vs. 28.6%, p < 0.01); this association was not observed for hsTnT. Conclusion: Preoperative measurement of MR-proADM provides useful information for perioperative cardiac events in high-risk patients scheduled for noncardiac surgery.

Impaired glucose tolerance is a state characterized by hyperglycemia, but with the levels of blood glucose between normal and diabetic values. Diabetic retinopathy is a complication of diabetes the pathogenesis of which is associated with oxidative stress. Metformin is currently the drug of first choice in the treatment of diabetes mellitus type 2. The objective was to determine whether there is oxidative damage to the retina in an animal model using the analysis of oxidative damage parameters, TBA reactive substances (TBARS) and advanced oxidative protein products (AOPP), and whether this damage can be mitigated by metformin tratment. The experiment was performed on 10 weeks old Wistar rats randomized into 4 groups. Impaired glucose tolerance was induced by intraperitoneal injection of streptozotocin (STZ), administered 15 minutes after an intraperitoneal injection of nicotinamide. After 4 weeks, metformin was introduced (100 mg/kg, per os). After 2 weeks, the animals were sacrificed under deep anesthesia. The concentrations of TBARS and AOPP in retinal homogenates were significantly higher in animals with impaired glucose tolerance compared to controls (TBARS: 4.09 ± 0.39 vs. 2.98 ± 0.26; p < 0.001 and AOPP: 34.49 ± 3.21 vs. 26.26 ± 3.16; p < 0.001). A strong positive correlation between serum glucose level and level of TBARS (r = 0.757, p < 0.01) and AOPP levels (r = 0.683, p < 0.01) was found. Metformin did not show any significant effects on the examined parameters. Values of the examined parameters indicate that impaired glucose tolerance causes a strong oxidative stress in the retina, which is the first step in the onset of diabetic retinopathy. Metformin therapy at a dose of 100 mg/kg, showed no significant beneficial effect on the process of lipid peroxidation and oxidation of proteins in the tissues of the retina in animals with impaired glucose tolerance.

Clinical practice and experimental studies have shown the necessity of sufficient quantities of folic acid intake for normal embryogenesis and fetal development in the prevention of neural tube defects (NTDs) and neurological malformations. So, women of childbearing age must be sure to have an adequate folate intake periconceptionally, prior to and during pregnancy. Folic acid fortification of all enriched cereal grain product flour has been implemented in many countries. Thus, hundreds of thousands of people have been exposed to an increased intake of folic acid. Folate plays an essential role in the biosynthesis of methionine. Methionine is the principal aminopropyl donor required for polyamine biosynthesis, which is up-regulated in actively growing cells, including cancer cells. Folates are important in RNA and DNA synthesis, DNA stability and integrity. Clinical and epidemiological evidence links folate deficiency to DNA damage and cancer. On the other hand, long-term folate oversupplementation leads to adverse toxic effects, resulting in the appearance of malignancy. Considering the relationship of polyamines and rapidly proliferating tissues (especially cancers), there is a need for better investigation of the relationship between the ingestion of high amounts of folic acid in food supplementation and polyamine metabolism, related to malignant processes in the human body.

Colorectal cancer is one of the most frequent neoplastic diseases in the human population, and one of the most frequent causes of death. Reactive oxygen species (ROS) are involved in the process of cancer initiation and progression. It is known that ROS are formed in excess in chronic diseases of the gastrointestinal tract, but the precise mechanisms of oxidative stress being induced in cancer cells and the role of ROS in colorectal cancer progression are still not exactly understood. Tumor tissue specimens as well the healthy colon tissue and the tissue surrounding the tumor were obtained from 50 primary colorectal cancers. The concentration of TBARS in the homogenate was determined by spectrophotometric method by Andreeva et al. AOPP concentrations in the tissue was measured by the spectrophotometric method by Vitko et al. Catalase activity in plasma was determined by spectrophotometric method by Goth. TBARS and AOPP levels were significantly higher in the tumor tissue compared to the control healthy tissue (p

The toxic effect of microwave radiation (MW) causes the change in the metabolism of polyamines. Polyamines (spermine and spermidine) and their precursor, diamin putrescine, are non-protein nitrogenous bases and they are essential to the function of the cell. Spermine and spermidine are catabolized by the enzyme polyamine oxidase (PAO), while the catabolism of putrescine is under the effect of the diamine oxidase (DAO). The neurohormon melatonin participates in maintaining the normal function of the immune system. The aim of this study was to analyze the effect of melatonin on the catabolism of polyamines in the rat thymus, following the chronic microwave exposure. Wistar rats were divided into four experimental groups: 1) control group, 2) Mel - the animals which were given melatonin daily (2mg/kg), 3) MW - the animals which were exposed to MW (4h daily), 4) the animals which were exposed to MW and were given melatonin daily. The animals were sacrificed after 20, 40 and 60 days of the experiment. There was an increase in the PAO activity and decrease in the DAO activity (already after 20 days) in comparison to the control in the thymus of rats exposed to microwave radiation. There was also a statistically significant positive correlation (p < 0.05) between malondialdhehyde levels and the activity of PAO during the MW exposure. A significant decrease in both PAO and DAO activity was found in the thymus of animals exposed to MW and treated with melatonin, in comparison to the irradiated animals not treated with melatonin.

BACKGROUND Microwaves from mobile phones are one of the environmental toxicants that are capable of compromising male fertility by inducing oxidative stress and apoptosis in the testes. Melatonin is a lipophilic tryptophan indole amine and a potent antioxidant. OBJECTIVES The aim of the study was to evaluate the effect of melatonin treatment on oxidative stress parameters and DNA fragmentation in the testicular tissue of rats exposed to microwave radiation (4 h/day). MATERIAL AND METHODS Adult Wistar rats were divided in 4 groups: I--treated with saline; II--treated with melatonin; III--exposed to microwaves; IV--exposed to microwaves and treated with melatonin. The melatonin (2 mg/kg ip) was administered daily. The animals were sacrificed after 20, 40 and 60 days. RESULTS Melatonin treatment prevented previously registered increases in malondialdehyde after only 20 days. Furthermore, it reversed the effects of microwave exposure on xanthine oxidase (after 40 days) and acid-DNase activity (after 20 days). However, neither protein carbonyl content nor catalase and alkaline Dnase activity were changed due to melatonin treatment. CONCLUSIONS Melatonin exerts potent antioxidant effects in the testes of rats exposed to microwaves by decreasing the intensity of oxidative stress; it also reduces DNA fragmentation.

OBJECTIVES We aimed to clarify if melatonin treatment (2 mg/kg i.p.) may favorably impact the liver tissue in rats exposed to microwave radiation. The experiment was performed on 84 six-weeks-old Wistar male rats exposed for 4h a day, for 20, 40 and 60 days, respectively, to microwaves (900 MHz, 100-300 microT, 54-160 V/m). Rats were divided in to four groups: I (control) - rats treated with saline, II (Mel) - rats treated with melatonin, III (MWs) - microwave exposed rats, IV (MWs + Mel) - MWs exposed rats treated with melatonin. We evaluated oxidative stress parameters (malondialdehyde and carbonyl group content), catalase, xanthine oxidase, deoxyribonuclease I and II activity. BACKGROUND Oxidative stress is the key mechanism of the microwave induced tissue injury. Melatonin, a lipophilic indoleamine primarily synthesized and released from the pineal gland is a powerful antioxidant. RESULTS Exposure to microwaves caused an increase in malondialdehyde after 40 (p < 0.01), protein carbonyl content after 20 (p < 0.05), catalase (p < 0.05) and xantine oxidase activity (p < 0.05) after 40 days. Increase in deoxyribonuclease I activity was observed after 60 days (p < 0.05), while deoxyribonuclease II activity was unaffected. Melatonin treatment led to malondialdehyde decrease after 40 days (p< 0.05), but surprisingly had no effect on other analyzed parameters. CONCLUSION Melatonin exerts certain antioxidant effects in the liver of rats exposed to microwaves, by diminishing the intensity of lipid peroxidation(Fig. 6, Ref. 32).

Cardiovascular repair and myocardial contractility may be improved by migration of bone marrow stem cells (BMSC) and their delivery to the site of injury, a process known as BMSC homing. The aim of our study was to examine the dietary effect of a newly patented depurinized milk (DP) that is almost free of uric acid and purine and pyrimidine compounds compared with a standard commercial 1.5% fat UHT milk diet or allopurinol therapy in rat experimental hyperuricemia. Bone marrow stem cell potential (BMCD34(+), CD34-postive bone marrow cells), plasma oxidative stress parameters [advanced oxidation protein products, AOPP) and thiobarbituric acid reactive substances (TBARS)], myocardial damage markers [creatine phosphokinase (CPK), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH)], plasma cholesterol, and high-density lipoprotein cholesterol were investigated. The DP milk diet significantly increased the number of BMCD34(+) stem cells compared with commercial UHT milk. Allopurinol given alone also increased the number of BMCD34(+). Hyperuricemia caused a significant increase in all plasma enzyme markers for myocardial damage (CPK, LDH, and AST). A cardioprotective effect was achieved with allopurinol but almost equally with DP milk and more than with commercial milk. Regarding plasma AOPP, TBARS, and cholesterol levels, the most effective treatment was DP milk. In conclusion, the protective role of a milk diet on cardiovascular function may be enhanced through the new depurinized milk diet, which may improve cardiovascular system function via increased bone marrow stem cell regenerative potential, decreased plasma oxidative stress parameters, and decreased levels of myocardial damage markers and cholesterol. New dairy technology strategies focused on eliminating harmful milk compounds should be completely nontoxic. Novel milk products should be tested for their ability to improve tissue repair and function.

6The aim of this research was to examine the relationship between inflammatory parameters and markers of cholestasis in patients with choledocholithiasis. All subjects underwent clinical, laboratory and ultrasound examination at the Department of Internal Medicine, Military Hospital Nis, Serbia. Inflammatory parameters and biochemical markers of cholestasis were measured by standard biochemical methods. Most of cholestasis markers showed no significant correlation with inflammatory parameters in blood, except for a weak significant correlation between the number of monocytes with the activity of aspartate aminotransferase (AST) (r=0.37, p

The aim of the study was to evaluate the effect of melatonin on oxidative stress, DNA fragmentation, apoptsis and proliferation in thymus tissue of rats exposed to microwaves. Wistar rats were divided in four groups: I - treated with saline; II - treated with melatonin; III - microwaves exposed; IV - microwaves exposed and melatonin treated. Melatonin (2 mg/kg i.p.) was administered daily. Animals were sacrificed after 20, 40 and 60 days. A significant increase in malondialdehyde and carbonyl group content, as well as decrease in catalase and increase in xanthine oxidase activity were registered under microwave exposure. Melatonin prevented the increase in malondialdehyde and carbonyl group content, and reversed the effect on catalase and xanthine oxidase activity. Both, alkaline and acid DNase activity were increased due to microwave exposure. Furthermore, microwaves caused increase in apoptosis rate (detected using Annexin V-FITC/PI kit) and reduced proliferative capacity of thymocytes (induced by ConA). However, melatonin caused decrease in alkaline and acid DNase activity, decrease in apoptotic rate and increase in proliferation rate of thymocytes. Melatonin exerts protective effects on rat thymocytes by modulating processes of apoptosis and proliferation, and causes decrease in DNA fragmentation and oxidative stress intensity under exposure to microwaves.

Accumulation of hydrophobic bile acids (BAs) during cholestasis plays an important role in apoptosis initiation as well as oxidative stress increase in liver cells. Ursodeoxycholic acid (UDCA) acts as a protector in BA-induced cell injury.The aim of the study was to evaluate the effect of UDCA on oxidative stress level and DNase I and II activity caused by liver injury in bile duct ligation (BDL) rats.Wistar rats were divided in four groups: group 1, control (sham-operated); group 2, sham-operated and injected with UDCA (30 mg/kg); group 3,animals with BDL; and group 4,UDCA-treatedcholestatic rats. Animals were sacrificed after 9 days. Malondialdehyde (MDA; lipid peroxidation end-product) level and protein-molecule oxidative modification (carbonyl group content) significantly increased in BDL rat liver. Catalase (CAT) activity in liver tissue was found to be decreased in BDL rats. In addition, xanthine oxidase (XO) activity, which is thought to be one of the key enzymes producing reactive oxygen species, was found to be increased in the cholestatic group. The apoptotic effect in cholestasis was probably triggered by the increased activation of DNase I and II. The protective effect of UDCA on liver tissue damage in BDL rats, in comparison to cholestatic liver, were 1) decrease of MDA levels, 2) increased CAT activity, 3) reduced XO activity, and 4) effect on terminal apoptotic reaction, shown as a decrease in DNase I and II activity.Therefore, UDCA may be useful in the preservation of liver function in cholestasis treatment.

Background: Microwave radiation (MW) produced by wireless telecommunications and a number of electrical devices used in household or in healthcare institutions may cause various disorders in human organ- ism. On the other hand, melatonin is a potent antioxidant, immunostimulator and neuromodulator. The aim of this research was to determine body mass and behaviour changes in rats after a chronic microwave exposure, as well as to determine the effects of melatonin on body mass and behaviour in irradiated rats. Methods: Wistar rats were divided into the four experimental groups: I group (control) - rats treated with 0,9 % saline, II group (Mel) - rats treated with melatonin (2 mg/kg), III group (MW) - rats exposed to MW radiation (4 h/day), IV group (MW+Mel) - rats, which were both exposed to MW radiation and received melatonin pre- medication (2 mg/kg). Results: A signifi cant body mass reduction was noted in animals exposed to MW radiation when compared to controls after 20, 40 and 60 days (p

Hyperuricaemia and gout are closely related, but hyperuricaemia is an independent risk factor for endothelial damage, autoinflammation and haemodynamic abnormalities. Milk, generally known as a 'purine-free diet', is an essential protein source for patients suffering from hyperuricaemia and gout. As milk still contains different purine ribonucleotides, the new product, depurinized milk, almost free of purine nucleotides and uric acid, was produced. The potential effect of depurinized milk diet on serum uric acid (SUA) level, lipid parameters and blood haematological parameters was explored in rats after 72 h and 15 days, in relation to standard laboratory chow or the untreated milk diet. The beneficial effect on SUA was achieved when depurinized milk draught was given instead of standard chow for 72 h [28.39 ± 4.76 μm; p < 0.001 vs. standard diet (STD) 47.6 ± 6.12, vs. untreated milk diet 31.55 ± 8.50; p < 0.05] or as a supplement for STD for 15 days experiment (35.38 ± 6.40 μm; p < 0.05 vs. STD only 48.05 ± 4.32; vs. untreated milk + STD 46.02 ± 9.48). Depurinized milk diet significantly decreased the low density lipoproteins/high density lipoproteins (LDL/HDL) ratio (p < 0.001), triglycerides (p < 0.05) and leucocyte count (p < 0.001), while both milk draughts enhanced haemoglobin concentration (p < 0.01). In conclusion, considering the detrimental effect of persisting hyperuricaemia, the depurinized milk draught may meet the demand of healthy dairy product for population under hyperuricaemic risk.

The sensing of ribonucleic acids (RNAs) by the monocyte/macrophage system occurs through the TLR7/8 Toll-like receptor family, the retinoic acidi–nducible protein I (RIG-I), and the melanoma differentiation–associated protein-5 (MDA-5). The aim of the present study was to evaluate the effect of circulating RNAs, isolated from juvenile type 1 diabetic patients and healthy control children, on the inflammatory, apoptotic, and antiviral response in human peripheral blood mononuclear cells (PBMCs) isolated from a healthy donor. Obtained effects were compared to the effects of metabolic stress parameters (hyperglycemia, oxidative and nitrosative stress). Forty-eight patients with juvenile type 1 diabetes and control children were included in the study. By performing the chromatographic analysis of circulating RNAs, the peak at the retention time 0.645 min for diabetic and control RNA samples was identified. To determine whether circulating RNAs have an agonistic or antagonistic effect on the signaling pathways involved in inflammatory, apoptotic, and antiviral cascade, their effect on TLR8, RIG-I, MDA-5, MyD88, NF-κB, IRF-3, phosphoIRF-3, IRF-7, RIP, and p38 was evaluated. A significantly lower level was achieved by cultivating PBMCs with circulating RNAs isolated from type 1 diabetic children, compared to the intact PBMCs, in relation to TLR-8, MDA-5, NF-κB, phospho IRF-3, and RIP, while it was higher for Bax. All the metabolic stress conditions up-regulated NF-κB, Bcl-2, and Bax. The NF-κB, determination seems to be the most sensitive parameter that may reflect disease processes associated with the progression of autoimmune or inflammatory conditions, while the IRF3/phosphoIRF3 ratio may suggest an insufficient antiviral response.

Diabetes mellitus is a metabolic disease characterized by inadequate secretion of insulin. Polyamine oxidase (PAO), a FAD-containing enzyme is involved in the biodegradation of Sp and Spd, catalyzing the oxidative deamination of Sp and Spd, resulting in production of ammonia (NH(3)), corresponding amino aldehydes and H(2)O(2). Malondialdehyde (MDA) and acrolein (CH2=CHCHO), potentially toxic agents, which induce oxidative stress in mammalian cells, are then spontaneously formed from aminoaldehydes. The main signs of oxidative stress in diabetic children were the values of HbA1c and MDA levels. Polyamines have an insulin-like action. Antiglycation property of spermine and spermidine has been recently confirmed. There are no data in the literature about plasma polyamine oxidase (PAO) activities in children with type 1 diabetes. The idea of this study was to evaluate the polyamine metabolism through the estimation of polyamine oxidase activity. We have study children with newly diagnosed type 1 diabetes mellitus (n = 35, age group of 5-16 years, as well as age-matched healthy control subjects (n = 25). The biochemical investigations were done on diabetic children who have the pathological values of glucose (9.11-17.33 mmol/l) and glycosylated Hb (7.57-14.49% HbA(1c)). The children in the control group have referent values of glucose and glycated hemoglobin (4.11-5.84 mmol/L and HbA(1c) 4.22-6.81% of the total Hb. Glucose levels in blood plasma and glycosylated hemoglobin in erythrocythes hemolysates (HbA1c) were measured by using standard laboratory methods. PAO activity in venous blood plasma and the amount of malondialdehyde (MDA) were measured by the spectrophotometric methods. PAO activity, glycemia, HbA1c and MDA were significantly increased in diabetic children compared to the control subjects. PAO activity in children with type 1 diabetes mellitus was very high. The findings of higher blood HbA(1C) and MDA levels confirm the presence of oxidant stress in children with type 1 diabetes mellitus and demonstrate that PAO activity may participate in these circumstances.

The immune response can be triggered by molecules derived from microorganisms (PAMP) or from molecules derived from damaged or dead host cells, known as the damage-associated molecular-pattern molecules (DAMP). Their immune effects are accompanied by altered redox environment. The level of stable end products of nitric oxide (NO)- plasma nitrate and nitrite (NOx), carbonyl groups (PCO) and nitrotyrosine (NTY), in relation to the metabolism of dsRNAs (poly I:C and poly A:U) and xanthine oxidase (XO activity), in plasma of type2 diabetic patients was determined. Thirty-six patients with type 2 diabetes (age group 34-66 years, 19 male and 17 female) were allocated to the study. Diabetic patients had a significantly higher level of plasma NOx products, NTY and PCO, fructosamine (FA) and XO activity indicating about altered redox environment. The concentration of circulating ribonucleic acids (CNAs) was significantly higher in type 2 diabetic patients, which was accompanied by a significantly decreased activity of RNase against double stranded RNA forms (poly I:C and poly A:U), compared to control samples. To determine whether CNAs, as possible DAMP molecules, are capable of exerting effect on inflammatory and host antiviral response, the effect of isolated CNAs on NF-kappaB, Bcl-2, Bax, MDA-5 and IRF-3 regulation was evaluated in culture of fresh isolated thymocytes. Circulating nucleic acids isolated from type 2 diabetic patients were able to upregulate NF-kappaB more than control RNA samples. In the same experimental conditions the mild Bcl-2 upregulation, followed by the marked Bax upregulation, was demonstrated. Since the Bcl-2/Bax ratio was lower in type 2 diabetic samples, obtained results may implicate that CNAs may exert proapoptotic response in type 2 diabetes. The CNAs isolated from diabetic patients were able to downregulate MDA-5 and IRF-3, very important subjects of the surveillance and cellular anti-viral response. The major findings of the present study are that impaired dsRNA metabolism may lead to increased level of different sized RNAs in type 2 diabetic patients. Acting as possible DAMP molecules, they may contribute to higher susceptibility of immune cells to inflammatory cascade via NF-kappaB activation, and possible MDA-5/IRF-3 axis downregulation, what may have an influence on further ineffective response against different pathogens.

The Significance of Urinary Markers in the Evaluation of Diabetic Nephropathy Oxidative stress is considered to be a unifying link between diabetes mellitus (DM) and its complications, including nephropathy (DN). The aim of this study was to determine the parameters of oxidative injury of lipids and proteins as well as the activity of ectoenzymes in the urine of DN patients. The study included 40 individuals: 10 patients with type 2 diabetes mellitus and microalbuminuria (DMT2-MIA), 10 type 2 diabetic patients with macroalbuminuria (DMT2-MAA), 10 patients with type 1 diabetes and microalbuminuria (DMT1-MIA) and 10 age- and sex-matched healthy subjects (control). In the urine we determined TBA reactive substances (TBARS), reactive carbonyl groups (RCG), and the activity of ectoenzymes N-acetyl-β-d-glucosaminidase (NAG), plasma cell differentiation antigen (PC-1), aminopeptidase N (APN) and dipeptidyl peptidase IV (DPP IV). A higher concentration of TBARS in the urine was found in DMT2-MIA and DMT1-MIA, compared to the control group (p

Foreign, infection-associated or endogenously generated circulating nucleotide motifs may represent the critical determinants for the activation of the Toll-like receptors (TLRs), leading to immune stimulation and cytokine secretion. The importance of circulating nucleases is to destroy nucleic acids and oligonucleotides in the blood stream and during cell entry. Patients with juvenile insulin-dependent diabetes, adult patients with insulin-dependent diabetes and adult patients with type 2 diabetes were allocated to the study, together with the age-matched control subjects. Plasma RNase and nuclease activity were examined, in relation to different substrates-TLRs response modifiers, and circulating RNA and oligonucleotides were isolated. The fall in enzyme activity in plasma was obtained for rRNA, poly(C), poly(U), poly(I:C), poly(A:U) and CpG, especially in juvenile diabetics. In order to test the non-enzymatic glycation, commercial RNase (E.C.3.1.27.5) and control plasma samples were incubated with increasing glucose concentrations (5, 10, 20 and 50 mmol/l). The fall of enzyme activity was expressed more significantly in control plasma samples than for the commercial enzyme. Total amount of purified plasma RNA and oligonucleotides was significantly higher in diabetic patients, especially in juvenile diabetics. The increase in the concentration of nucleotides corresponded to the peak absorbance at 270 nm, similar to polyC. The electrophoretic bands shared similar characteristics between controls and each type of diabetic patients, except that the bands were more expressed in diabetic patients. Decreased RNase activity and related increase of circulating oligonucleotides may favor the increase of nucleic acid "danger motifs", leading to TLRs activation.

It has been demonstrated that administration of high concentrations of monosodium glutamate (MSG), induce oxidative stress in different organs, but not in thymus. In the present study we examined the role of oxidative stress in MSG-induced thymocyte apoptosis. MSG was administrated intraperitoneally (4 mg/g of body weight) for six consecutive days. Animals were sacrificed at 1st, 7th, and 15th day after last MSG dose. MSG administration to animals significantly increased apoptotic rate of thymocytes (P < 0.01), together with significant increase of malondialdehyde (MDA) level (P < 0.001) and xanthine oxidase (XO) activity (P < 0.01), in time dependent manner. Catalase activity, during examination period, was significantly decreased (0 < 0.01). Obtained results showed that MSG treatment induced oxidative stress in thymus, which may have an important role in thymocyte apoptosis induced by MSG.

Disturbance In The Composition of Lipoprotein Particles And Chronic Inflammation As Prognostic Factors In The Development of Coronary Disease The study focused on 30 dyslipidemic patients (12 women and 18 men); 16 of them had coronary disease (CD). The concentrations of apoA and apoB were determined in all patients, as well as the calculated ratio between apoA and apoB. As far as inflammatory indicators are concerned, the concentrations of sensitive C reactive protein (hsCRP), albumin, fibrinogen, intracellular adhesive molecule (ICAM-1) and vascular adhesive molecule (VCAM -1) were determined. In patients with CD there were considerably higher concentrations of fibrinogen (3.1 ± 1.2 vs. 2.7 ± 0.7 g/L) and VCAM-1 (10.9 ± 3.6 vs. 8.3 ± 2.8 g/L) (p

Polyamines, spennine, spermidine and putrescinc, small aliphatic nitrous bases, are normal constituents of microbial, plant and animal cells, where they fulfill an array of physiological roles. Metabolism of polyamines is associated with growth and differentiation of mammalian cells, spermine related to RNA and spermidine to DNA metabolism. Methyl-cobalamin, the coenzyme of methionine synthetase, catalyses the recycling of homocysteine to methionine using 5-methyltctrahydrofolate. By acceleration of methionine biosynthesis these vitamins may influence spermidine and spermine synthesis. Liver tissue is rich in polyamines and it is the place of vitamin B12 and folic acid deposition. Polyamine oxidase (PAO, EC 1.5.3) and diamino oxidase (DAO, EC 1.4.3.6) participate in the process of degradation and interconversion of spermine, spermidine and putrescinc. The idea of our work was to examine the effccts of cobalamin and folic acid on the polyamine metabolism. We have examined the amount of spermine, spermidine and putrescine in liver tissue. At the same time we have examined the activities of PAO and DAO, the catabolic enzymes of polyamine metabolism. Our result suggest that the supplementation of experimental animals with vitamin B12 alone or together with folic acid augmentais spermidine and spermine levels in rat liver, at the same time the amount of putrescine does not change. The application of vitamin cobalamin to experimental animals alone increases PAO; the supplementation of experimental animals with vitamin Β12 together with folic acid causes opposite effect - the decrease of PAO activity. DAO activity significantly decreases under the influence of cobalamin and also with cobalamin and folic acid in combination. Our experimental results indicate the importance of cobalamin and folic acid in polyamine metabolism.

The pathogenesis of encephalopathy in cholestasis results from the accumulation of unconjugated bilirubin and hydrophobic bile acids in the brain. Putrescine, spermidine and spermine are endogenous polyamines essential for cellular growth, proliferation and regeneration. The amino-acid L-methionine is required for the biosynthesis of polyamines. The aim of the study was to examine the effect of L-methionine in polyamine metabolism on the cholestatic brain of injured rats. Wistair rats were divided into 3 groups: I - control, II - bile duct ligated (BDL) rats, III - BDL rats treated with L-methionine (50 mg/kg BW). Cholestasis in rats’ brain increases the putrescine level (p

Aim: The ribonuclease (RNase) family represents important enzymes used widely in biomedical and biotechnological applications, as well as for diagnostic and therapeutic purposes. This study was undertaken to test the possibility that plasma alkaline RNase (free or inhibitory bound) determination may be useful in studying the dysregulation of nucleic acid and oligonucleotide metabolism as a possible pathogenetic mechanism in development of immune dysfunction in juvenile diabetes mellitus. Patients and methods: Children with type 1 diabetes (n = 32, age group of 5–14 yr), together with age-matched control subjects (n = 35), were enrolled in the study. None had microvascular complications. According to the metabolic regulation of the disease and the hemoglobin A1c (HbA1c) level, all patients were divided into two groups (HbA1c 7.5%). According to the duration of diabetes, diabetic children were divided into two groups: duration of diabetes less than 1 yr and duration of diabetes greater than 1 yr. The control group consisted of age-matched subjects (n = 35; 15 girls and 20 boys) who were clinically healthy. The activity of free and inhibitory-bound RNase and the level of acid soluble nucleotides were measured in heparinized plasma. Results: The inhibitory-bound enzyme activity was higher in diabetic children, followed by sharply decreased free enzyme, especially in the group with the level of HbA1c above 7.5%. Recent-onset diabetic patients had lower free RNase activity compared with those with longer duration of the disease. The amount of pre-existing acid-soluble oligonucleotides was significantly increased in diabetic children, especially in those with poor metabolic control. Conclusion: Our observed preliminary results may suggest a hypothesis that a persistent increase of oligonucleotide fragments, most probably due to insufficient RNase activity, may lead to T-cell hyperactivity in type 1 diabetes through the activation of toll-like receptors (TLRs). The measurement of RNase(s) activity (free, inhibitory-bound, or specific toward different substrates), together with the well-known immunobiochemical parameters of diabetes, may help further efforts in identifying a disease-specific early biological marker of immunity dysfunction in juvenile diabetes.

Amidinotransferase (transamidinase, L-arginine: glycine amidinotransferase, EC 2.1.4.1) is an enzyme that catalyses the first step in creatine synthesis primarily in the kidney and pancreas. The kidney is also the primary target organ for the toxic effect of mercury. Therefore, we studied the effect of acute uremic syndrome on enzyme activity induced by mercury chloride. Because of the potential beneficial effect of bioflavonoids, we have investigated the effects of the bioflavonoid lespeflan on acute uremic syndrome and amidinotransferase activity. Male Spraque Dawley rats weighing about 200 g were used in this study. Acute renal failure was induced by intraperitoneally (i.p.) administration of mercury chloride in a dose of 3 mg/kg. One group of animals was given lespeflan (1.0 mL/kg) 1 hr before mercury chloride administration. Urea and creatinine levels in blood plasma were significantly elevated 48 hr after the induction of acute uremic syndrome (p< 0.001). Kidney transamidinase activity was decreased compared to the control group (p

Purine nucleotide liberation and their metabolic rate of interconversion may be important in the development of hypertension and its renal consequences. In the present study, blood triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) breakdown pathway was evaluated in relation to uric acid concentration and xanthine dehydrogenase/xanthine oxidase (XDH/XO) in patients with essential hypertension, patients with chronic renal diseases on dialysis, and control individuals. The pattern of nucleotide catabolism was significantly shifted toward catabolic compounds, including ADP, AMP, and uric acid in patients on dialysis program. A significant fall of ATP was more expressed in a group of patients on dialysis program, compared with the control value (p

Hyperuricemia is a biochemical hallmark of gout, renal urate lithiasis, and inherited purine disorders, and may be a result of enormous ATP breakdown or purine release as a result of cardiovascular disease, hypertension, kidney disease, eclampsia, obesity, metabolic syndrome, psoriasis, tumor lysis syndrome, or intense physical training. The beneficial role of dairy products on hyperuricemia management and prevention is well documented in the literature. The primary aim of our experimental study was to examine the effect of milk dietary regimen (commercial 1.5% fat UHT milk or patented depurinized milk) compared with allopurinol therapy on experimental hyperuricemia induced by oxonic acid in rats. Principal component analysis was applied on a data set consisting of 11 variables for 8 different experimental groups. Among the 11 parameters measured (plasma uric acid and the liver parameters NFκB-p65, Akt kinase/phospho-Akt kinase, ERK kinase/phospho-ERK kinase, IRAK kinase/phospho IRAK kinase, p38/phospho-p38, and DNase), Akt/phospho Akt and ERK/phospho-ERK signaling were extracted as the most discriminating. We also compared the content of various potentially toxic compounds (sulfur compounds, ketones, aldehydes, alcohols, esters, carboxylic acids, and phthalates) in untreated commercial milk and depurinized milk. Of all the compounds investigated in this study that were observed in commercial milk (24 volatile organic compounds and 4 phthalates), 6 volatile organic compounds were not detected in depurinized milk. For almost all of the other compounds, significant decreases in concentration were observed in depurinized milk compared with commercial milk. In conclusion, a depurinized milk diet may be recommended in nutritional treatment of primary and secondary hyperuricemia to avoid uric acid and other volatile, potentially toxic compounds that may slow down liver regeneration and may induce chronic liver diseases.

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.

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.

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.

L-arginine is conditionally essetcial amino acid, required for normal cell growth, protein synthesis, ammonia detoxification, tissue growth and general performance, proposed in the treatment of men sterility and prevention of male impotence. The aim of the present paper was to estimate the activity of the enzymes of adenine nucleotide metabolism:5′-nucleotidase (5′-NU), adenosine deaminase (ADA), AMP deaminase, and xanthine oxidase (XO), during dietary intake of L-arginine for a period of four weeks of male Wistar rats. Adenosine concentration in tissues is maintained by the relative activities of the adenosine-producing enzyme,5′-NU and the adenosine-degrading enzyme-ADA adenosine deaminase. Dietary L-arginine intake directed adenine nucleotide metabolism in liver, kidney, and testis tissue toward the activation of adenosine production, by increased5′-NU activity and decreased ADA activity. Stimulation of adenosine accumulation could be of importance in mediating arginine antiatherosclerotic, vasoactive, immunomodulatory, and antioxidant effects. Assuming that the XO activity reflects the rate of purine catabolism in the cell, while the activity of AMP deaminase is of importance in ATP regeneration, reduced activity of XO, together with the increased AMP-deaminase activity, may suggest that adenine nucleotides are presumably directed to the ATP regenerating process during dietary L-arginine intake.

Under physiological conditions insulin controls the metabolism of carbohydrates, lipids and proteins. Diabetes mellitus is a metabolic disease characterized by a disturbance in the intermediary metabolism of glucose and glucose-induced insulin release. Arginase (L-arginine amidinohydrolase, EC 3.5.3.1) modulates nitric oxide synthase activity by regulating intracellular L-arginine availability. In diabetes mellitus, a decrease in nitric oxide bioavailability is a central mechanism for endothelial dysfunction. The aim of our study was to assess arginase activity in the blood of children with diabetes mellitus. Blood arginase activity, serum glucose (14.155 +/- 4.197 mmol/L; p < .001) and blood HbA1c (11.222 +/- 3.186 %; p < .001), were significantly higher in diabetic children than in healthy controls, whereas the magnesium (Mg2+) level, a cofactor of many enzymes, was significantly lower (0.681 +/- 0.104 micromol; p < .001). In diabetic children, arginase activity, hyperglycemia (r = 0.143), and the HbA1, level (r = 0.381) showed a positive correlation between but a negative correlation between Mg2+ and arginase activity (r= -0.206). The higher arginase activity and the lower Mg2+' levels in diabetic children could be a consequence of reduced insulin action and increased protein catabolic processes in these pathophysiological conditions. The inverse directions of arginase activity and serum Mg2+ levels are in agreement with this concept.

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.

BACKGROUND Neonatal hyperbilirubinemia can be physiological and pathological and most frequently is a consequence of faster erythrocytes (RBC) hemolysis. Free unconjugated bilirubin is a highly toxic compound, especially for the central nervous system. The most abundant polyamines circulating in blood are spermidine (Spd) and spermine (Sp), which are mainly localized in RBC, where they control membrane permeability. Polyamine oxidase (PAO) exerts an important activity in the plasma and erythrocytes of newborn infants with hyperbilirubinemia, catalyzing the oxidative deamination of Sp and Spd, producing potentially toxic agents that induce apoptosis of mammalian cells. The present study investigated polyamine metabolism by measuring PAO activity in the blood of newborn infants with hyperbilirubinemia and explored the possible antioxidant function of bilirubin through monitoring malondialdehyde (MDA) levels. METHODS The study included 43 newborns, 10 in the control and 33 in the diseased group. Blood PAO activity and bilirubin and MDA levels were measured using spectrophotometric methods. RESULTS/DISCUSSION Our results indicate that bilirubin, at physiologic concentrations, protects neonatal erythrocytes against oxidative stress. The positive correlation between PAO activity and MDA levels with high bilirubin concentrations (> 200 micromol/L) in newborn infants indicates that in pathological conditions, bilirubin cannot exert its antioxidant function. CONCLUSION Investigating the function of polyamines in erythrocytes and the importance of PAO related to hemolysis and bilirubin synthesis is necessary to shed light on the functions of PAO and its metabolites on the permeability of the erythrocyte membrane.

Melatonin/Oxidative stress/Microwave radiation/Mobile phones/Brain. Purpose: The aim of the study was to evaluate the intensity of oxi dative 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 mi crowave 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 t issue 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 im portant 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.

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 γ-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 establishs a neuroprotective role in the brain during cholestasis.

Background/Aim: Confusing data have been reported about the effect of ethanol or its metabolic products on blood pressure. The pressor agent, angiotensin II (Ang II), is found to be susceptible to degradation by different enzymes known as angiotensinases. We have studied the effects of ethanol and L-NAME, an inhibitor of nitric oxide synthase, consumption on rat serum and kidney ectoenzymes: aminopeptidase N (APN) and aminopeptidase A (APA). Methods: Enzymatic activity of both enzymes was determined spectrophotometrically in serum and 10% homogenates of the rat kidney cortex using appropriate chromogenic substrates. Results: After 2 weeks of treatment with ethanol and L-NAME, blood urea and creatinine levels were significantly increased. The activities of APN (EC 3.4.11.2) and APA (EC 3.4.11.7) were reduced in serum as well as in kidney tissue during this period. L-NAME significantly attenuated activities of both enyzmes. Ethanol and L-NAME given simultaneously did not have an additional effect on the activity of investigated enzymes. Conclusion: Hypertension caused by chronic ethanol treatment as well as L-NAME administration could be associated with the reduction of APN and APA activity. Possible ethanol- and L-NAME-mediated inhibition of angiotensins degrading aminopeptidases could potentiate their effects on blood pressure.

The existing interrelation in metabolic pathways of L-arginine to polyamines, nitric oxide (NO) and urea synthesis could be affected in sepsis, inflammation, intoxication and other conditions. The role of polyamines and NO in the toxic effect of mercury chloride on rat liver function was studied. Administration of mercury chloride for 24 h led to significantly elevated plasma activities of Alanine transaminase (ALT) and Aspartate transaminase (AST). Malondyaldehyde (MDA) levels were unaffected (p > 0.05) and arginase activity was significantly decreased (p < 0.05) while nitrate/nitrite production was significantly elevated (p < 0.001) in liver tissue. Polyamine oxidase (PAO) and diamine oxidase (DAO) activities, enzymes involved in catabolism of polyamines, were decreased. L-arginine supplementation to intoxicated rats potentiated the effect of mercury chloride on NO production and it was ineffective on arginase activity. Results obtained in this study show that mercury chloride-induced toxicity leads to abnormally high levels of ALT and AST that may indicate liver damage with the involvement of polyamine catabolic enzymes and NO.

Acute renal failure (ARF) is a serious damage of renal function induced by various nephrotoxic drugs, ischemia, bilateral urethral obstruction, trauma and unilateral nephrectomy. Dramatic clinical syndrome, azotemia, develops as a result of hypovolemia, oliguria, reduced glomerular filtration and acidosis. In addition to classic medications recent studies give more attention to beneficial effect of natural plant products as bioflavonoids. We have studied the influence of bioflavonoid, quercetin, on hepatic urea production in glycerol induced ARF in the rats. Male Sprague Dawley rats were used in the experiment. The value of urea production in the liver was determined by measuring of liver arginase activity, the terminal enzyme of urea cycle. Arginase activity was increased (p0.01) as well as urea level (p0.001) 48 h after glycerol administration. Pretreatment by quercetin suppressed the arginase activity in the liver (p0.05) and plasma levels of urea (p0.01). So, we have concluded that quercetin may be beneficial in glycerol induced ARF.