Cerebrospinal fluid purinomics as a biomarker approach to predict outcome after severe traumatic brain injury.

Severe traumatic brain injury (TBI) is associated with high rates of mortality and long-term disability linked to neurochemical abnormalities. Although purine derivatives play important roles in TBI pathogenesis in preclinical models, little is known about potential changes in purine levels and their implications in human TBI. We assessed cerebrospinal fluid (CSF) levels of purines in severe TBI patients as potential biomarkers that predict mortality and long-term dysfunction. This was a cross-sectional study performed in 17 severe TBI patients (Glasgow Coma Scale <8) and 51 controls. Two to 4 h after admission to ICU, patients were submitted to ventricular drainage and CSF collection for quantification of adenine and guanine purine derivatives by HPLC. TBI patients' survival was followed up to 3 days from admission. A neurofunctional assessment was performed through the modified Rankin Scale (mRS) 2 years after ICU admission. Purine levels were compared between control and TBI patients, and between surviving and non-surviving patients. Relative to controls, TBI patients presented increased CSF levels of GDP, guanosine, adenosine, inosine, hypoxanthine, and xanthine. Further, GTP, GDP, IMP, and xanthine levels were different between surviving and non-surviving patients. Among the purines, guanosine was associated with improved mRS (p = 0.042; r = -0.506). Remarkably, GTP displayed predictive value (AUC = 0.841, p = 0.024) for discriminating survival versus non-survival patients up to 3 days from admission. These results support TBI-specific purine signatures, suggesting GTP as a promising biomarker of mortality and guanosine as an indicator of long-term functional disability.

XANTHINE NEPHROLITHIASIS IN JUVENILE CAPTIVE GIANT OTTERS (PTERONURA BRASILIENSIS).

Nephrolithiasis has been reported in several aquatic mammals including bottlenose dolphins (Tursiops truncatus), small clawed otters (Amblonyx cinereus), European river otters (Lutra lutra), North American river otters (Lontra canadensis), northern elephant seals (Mirounga angustirostris), Florida manatees (Trichechus manatus latirostris), and California sea lions (Zalophus californianus). Compositions of calculi in previous cases were predominantly calcium oxalate or ammonium acid urate. Xanthine urolithiasis is rare in veterinary medicine. Primary cases (without exposure to xanthine dehydrogenase inhibitors) occur as a consequence of hereditary xanthinuria, although the causal mutation has only been discovered in a subset of cases. Five captive juvenile giant otters (Pteronura brasiliensis) from two facilities were diagnosed with nephrolithiasis: three siblings from one set of parents and two siblings from another pair. Serum analyte assays revealed renal compromise in affected individuals. Computed tomography (CT) confirmed the presence of nephrolithiasis in one individual. Postmortem evaluation identified extensive bilateral nephrolithiasis on gross necropsy in four of five cases. Calculus analyses identified 100% xanthine composition. Histologic examination revealed marked nephrolithiasis with associated tubular necrosis and gastric mineralization. Nutrient composition of the diet including mineral and purine content was assessed. No association between diet and nephroliths was found in this study. This is the first report of xanthine nephrolithiasis in aquatic mammals. The potential role of diet and genetics in xanthine nephrolithiasis in the small inbred population of giant otters under human care needs further investigation to assess the implications of this disease process for the long-term captive management of this species.

Marigold carotenoids: Much more than lutein esters.

Carotenoids constitute a large group of lipophilic pigments whose health-promoting benefits have been widely recognized. Hydroxy-containing carotenoids can be found in both free form or esterified with fatty acids in several plant matrices, but the native carotenoid profile is overall poorly explored due to the difficulty of analyzing carotenoid esters. One of the main natural sources of carotenoids is the marigold flower, which has been extensively used by the industry for the production of food colorants or supplements, both often manufactured with no saponification process. Although lutein esters are well established as the major compounds naturally found in marigold petals and their products, carotenoid esters other than the lutein ones have not been extensively examined. We carried out a comprehensive identification of carotenoids and carotenoid esters from marigold petals by LC-DAD-(APCI+)MS/MS. Whereas 18 carotenoids were identified in the saponified extract, 56 were identified when no saponification procedure was carried out: 6 free carotenoids, 20 monoesters and 30 diesters. This is the first time that esters of zeaxanthin, violaxanthin, auroxanthin, zeinoxanthin and ß-cryptoxanthin are identified in marigold. The structural information obtained through characteristic fragmentation patterns and diagnostic fragments in MS and MS/MS spectra (APCI+) sustained the differentiation between carotenoid esters with similar characteristics. Therefore, the separation of carotenoids by reversed-phase liquid chromatography using C30 columns in combination with DAD and APCI-MS/MS detection allowed high sensitivity and selectivity for carotenoid ester analysis.

The Influence of a Xanthine-Catechin Chemical Matrix on in vitro Macrophage-Activation Triggered by Antipsychotic Ziprasidone.

Ziprasidone (ZIP) is an effective antipsychotic with low side effects than other second-generation antipsychotics. Despite this, there are reports of adverse events and previous studies associating the use of ZIP the inflammatory response. It is possible to infer that bioactive molecules present in some foods could attenuate peripheral inflammatory and oxidative stress potentially triggered ZIP. This is the case of guaraná xanthine-catechin chemical matrix (XC-Mix) that presents caffeine, theobromine, and catechin. The in vitro protocols using murine RAW 264.7 cell macrophages were ZIP-exposure in culture medium supplemented with chemical isolated and admixture of Caf, The, and Cat. Main results showed that supplementation with isolated and XC-mix had a lowering effect on 72 h macrophages proliferation. XC-mix with 1:1:1 proportion at 25 µg/mL of each caffeine, theobromine, and catechin, molecules present lowering effect on nitric oxide levels, oxidative stress markers (DNA oxidation quantified by 8-hydroxy-2' -deoxyguanosine), lipoperoxidation, and protein carbonylation. XC-mix also decreased protein levels and downregulated genes of proinflammatory cytokines (IL-1ß, IL-6, TNF-α). At contrary, XC-Mix increased levels and upregulated gene of anti-inflammatory IL-10 cytokine. The results suggest that XC-matrix could present some beneficial action on peripheral proinflammatory effects ZIP-triggered. Complementary in vivo studies could be useful to confirm these in vitro findings described here.

Xanthine-Catechin Mixture Enhances Lithium-Induced Anti-Inflammatory Response in Activated Macrophages In Vitro.

Lithium (Li) is a chemical element used for treating and preventing bipolar disorder (BD) and exerts positive effects such as anti-inflammatory effects as well as undesirable side effects. These effects of Li can be influenced by interaction with some nutritional elements. Therefore, we investigated the potential effects of xanthine (caffeine and theobromine) and catechin molecules present in some food beverages broadly consumed worldwide, such as coffee and tea, on Li-induced anti-inflammatory effects. In the present study, we concomitantly exposed RAW 264.7 macrophages to Li, isolated xanthine and catechin molecules, and a xanthine-catechin mixture (XC mixture). We evaluated the effects of these treatments on cell proliferation, cell cycle progression, oxidative and antioxidant marker expression, cytokine levels, gene expression, and GSK-3ß enzyme expression. Treatment with the XC mixture potentialized Li-induced anti-inflammatory effects by intensification of the following: GSK-3ß inhibitory action, lowering effect on proinflammatory cytokines (IL-1ß, IL-6, and TNFα), and increase in the levels of IL-10 that is an anti-inflammatory cytokine. Despite the controversial nature of caffeine consumption by BD patients, these results suggested that consumption of caffeine, in low concentrations, mixed with other bioactive molecules along with Li may be safe.

Increased oxidative stress alters nucleosides metabolite levels in sickle cell anemia.

OBJECTIVES: This study was conducted to assess the markers of oxidative stress, myeloperoxidase (MPO), acetylcholinesterase (AChE) and xanthine oxidase (XO) activities as well as the levels of nucleotide metabolites in sickle cell anemia (SCA) patients. METHODS: Fifteen SCA treated patients and 30 health subjects (control group) were selected. The markers of oxidative stress (levels of reactive oxygen species (ROS), plasma proteins, carbonyl content, lipid peroxidation (TBARS), total thiols (T-SH), glutathione and catalase activity), MPO, AChE and XO activities as well as the levels of nucleotide metabolites were measured in SCA patients. RESULTS: ROS, thiobarbituric acid-reactive substances (TBARS) and T-SH levels as well as the activities of catalase and MPO were significantly increased while glutathione level was reduced in SCA patients. Furthermore, a significant (P < 0.001) increase in hypoxanthine level was demonstrated in SCA patients. However, the serum levels for xanthine (P < 0.01) and uric acid (P < 0.001) were decreased in SCA patients. A significant (P < 0.001) decrease in XO activity was detected in SCA patients. DISCUSSION: The altered parameters in SCA patients suggest that the generation and impairment of oxidative stress in this disease as well as antioxidant markers are contributory factors towards cellular redox homeostasis and alteration of purine metabolites.

Caffeine in Brazil: intake, socioeconomic and demographic determinants, and major dietary sources

Background: The objectives of the study were to describe caffeine intake by 10 years of age or older Brazilian individuals and to investigate possible associations with demographic and socioeconomic determinants as well as the major dietary sources. Methods: The data used are from the personal food consumption module (n= 34,003) of a country-representative household budget survey. Consumed foods and beverages were identified during the application of food diaries. Caffeine contents in food and beverage sources were obtained primarily in national publications. Multivariate regressions were calculated to assess the correlations between population factors and caffeine intake. Results: The daily intake per person was estimated as 115.7 mg, ranging from 84.7 mg, for 10­13 years of age children and adolescents, to 139.8 mg, for individuals with no education. The percentage of individuals whom diet reveals daily caffeine intake higher than 400 mg is up to 3.0 %, according to age groups. Males and individuals living in the Northeast or South regions or in the states of Minas Gerais, Rio de Janeiro, and Espírito Santo are likely to ingest higher contents of the substance. The major dietary sources are coffee (63.1 %) and coffee with milk (24.9 %), cola soft drinks (3.6 %) and yerba mate (1.9 %).Conclusions: Caffeine intake in Brazil is below the recommended limit reference value for adults, and the percentage of individuals whom diet reveals excessive content of caffeine is low. Thus, excessive caffeine intake may not be a health issue in Brazil and depends on the domicile and gender. The major source in the Brazilian diet is coffee.

Effects of moderate electrical stimulation on reactive species production by primary rat skeletal muscle cells: cross talk between superoxide and nitric oxide production.

The effects of a moderate electrical stimulation on superoxide and nitric oxide production by primary cultured skeletal muscle cells were evaluated. The involvement of the main sites of these reactive species production and the relationship between superoxide and nitric oxide production were also examined. Production of superoxide was evaluated by cytochrome c reduction and dihydroethidium oxidation assays. Electrical stimulation increased superoxide production after 1 h incubation. A xanthine oxidase inhibitor caused a partial decrease of superoxide generation and a significant amount of mitochondria-derived superoxide was also observed. Nitric oxide production was assessed by nitrite measurement and by using 4,5-diaminofluorescein diacetate (DAF-2-DA) assay. Using both methods an increased production of nitric oxide was obtained after electrical stimulation, which was also able to induce an increase of iNOS content and NF-κB activation. The participation of superoxide in nitric oxide production was investigated by incubating cells with DAF-2-DA in the presence or absence of electrical stimulation, a superoxide generator system (xanthine-xanthine oxidase), a mixture of NOS inhibitors and SOD-PEG. Our data show that the induction of muscle contraction by a moderate electrical stimulation protocol led to an increased nitric oxide production that can be controlled by superoxide generation. The cross talk between these reactive species likely plays a role in exercise-induced maintenance and adaptation by regulating muscular glucose metabolism, force of contraction, fatigue, and antioxidant systems activities.

Pyrogallol red oxidation induced by superoxide radicals: application to evaluate redox cycling of nitro compounds.

The bleaching of the pyrogallol red (PGR) dye mediated by superoxide anion radicals (O(2)(-)) generated from the xanthine/xanthine oxidase system (X/XO) was studied by UV-visible spectrophotometry. The absorption band (at 540 nm) of PGR quickly decreased in the presence of X/XO, implying an efficient reaction of O(2)(-) with PGR. The process was unaffected by catalase (CAT), but completely abolished by superoxide dismutase (SOD). A mechanism of the reaction involving the consumption of one PGR molecule by two O(2)(-) to generate one molecule of H(2)O(2) is proposed. PGR was used as a probe to estimate the rate of O(2)(-) generation in redox cycling reactions of a series of nitro compounds mediated by rat liver microsomes. The consumption of PGR induced by the redox cycling of nitrofurantoin was totally eliminated by the addition of SOD but unaffected by CAT. The initial rate of consumption of PGR mediated by the redox cycling of others nitro derivatives follows the order: furazolidindione > nitrofurantoin > nifurtimox > benznidazole > chloramphenicol. We concluded that PGR can be used as a probe to estimate the release of O(2)(-) from enzymatic systems or from the redox cycling of nitro compounds.

Anomalias cromáticas em Bothrops jararaca (Serpentes, Viperidae) Xantismo interfere na sobrevivência?

Esse artigo descreve pela primeira vez xantismo em dois exemplares de B. jararaca e um acidente ofídico causado por um desses espécimes. Possíveis vantagens adaptativas para as espécies portadoras de tal anomalia cromática são discutidas. Para isso, foram analisados um exemplar macho proveniente de Jaraguá do Sul – SC e uma fêmea (responsável pelo acidente ofídico) proveniente de São Roque – SP. Ambos os espécimes apresentaram coloração característica de xantismo. A dissecção e análises ovarianas demonstraram folículos em início de vitelogênese, indicativo de período reprodutivo e com características de nuliparidade. A dissecção e análise gonadal do macho mostraram a presença de ducto deferente enovelado, indicativo de maturidade sexual. O quadro clínico do paciente mostrou tratar-se de um caso típico de acidente botrópico, apresentando sintomatologia característica para esse tipo de acidente ofídico. Os resultados obtidos corroboram dados da literatura para outros casos de xantismo, com ocorrência em serpentes de hábito noturno, adultas e em idade reprodutiva. Foi constatada que a perda da coloração críptica habitual não conferiu vantagens, ou seja, o xantismo, provavelmente alterou as chances de sobrevivência em serpentes de hábitos não predominantemente noturnos.

Chromatic anomalies in Bothrops jararaca (Serpentes, Viperidae): Does xanthism affect survival? This article describes, for the first time, the xanthism in two specimens of B. jararaca. It also describes the snakebite caused by one of these specimens, followed by a discussion on the adaptive advantages (e.g. survival).

Avaliação da proliferação de linfócitos T CD8+ por células dendríticas desafiadas com pró-oxidantes / Assesment of T CD8+ lympocytes proliferation by dendritic cells challenged with pro-oxidants

As células dendríticas são apresentadoras de antígeno mais eficazes para iniciar resposta primaria de linfocitos T. Quando internalizado o antígeno e processado gerando peptideos que serão apresentados por complexos de histocompatibilidade do tipo I em celulas dendriticas, os antigenos proteicos no citoplasma são processados pelo imunoproteassomo. Uma vez que celulas dendriticas estão nativamente expostas a uma serie de agentes estressantes incluindo os pro oxidantes, nosso objetivo neste trabalho foi examinar o efeito de pro oxidantes em celulas dendriticas para posterior avaliacao de linfocitos TCD8+... .

Dendritic cells are the most effect antigen presenting cells in starting sumary response of T lymphocytes. Once internalized, the antigen is processing generating peptides that are be presented the major histocompatibility complex type I, the cytosolic protein antigens must be processed by the imunoproteasome. Since dendritic cells are natively exposed to a variety of stress agents including pro oxidants our goal in this study was to examine the effect of pro oxidants in dendritic cell-induced TCD8 +... .

Photosensitized oxidation of hypoxanthine and xanthine by aluminum phthalocyanine tetrasulfonate. Role of the alkylating quinone 2,5-dichloro-diaziridinyl-1,4-benzoquinone.

Photoirradiation of nitrogen-saturated aqueous solutions containing aluminum phthalocyanine tetrasulfonate (AlPcS4) at 675 nm in the presence of 2,5-dichloro-diaziridinyl-1,4-benzoquinone (AZDClQ) and hypoxanthine (HX) produces the oxidized HX derivatives, xanthine (X) and uric acid (UA). Concentrations of the AZDClQ semiquinone, X and UA increase at the expense of HX with an increase in irradiation time. Almost negligible decomposition of HX, as well as very low amounts of X, are detected if photolysis occurs under identical conditions but in the absence of AZDClQ. Addition of calf-thymus DNA produces quinone-DNA covalent adducts after photolysis of anaerobic samples containing quinone, DNA and AlPcS4, in the presence or absence of HX and at pH 5.5. However, larger amounts of quinone-DNA adducts are detected if HX is present. The results presented here could have applications in the photodynamic treatment of hypoxic tissues such as solid tumors, under conditions of high HX concentration, where Type-I pathways could be more important than singlet oxygen generation.

Biochemical and structural characterization of the hypoxanthine-guanine-xanthine phosphoribosyltransferase from Pyrococcus horikoshii.

The 6-oxopurine phosphoribosyltransferase (HPRT, EC 2.4.2.8) from the hyperthermophile Pyrococcus horikoshii was expressed in Escherichia coli and purified. Steady-state kinetic studies indicated that the enzyme is able to use hypoxanthine, guanine and xanthine. The first two substrates showed similar catalytic efficiencies, and xanthine presented a much lower value (around 20 times lower), but the catalytic constant was comparable to that of hypoxanthine. The enzyme was not able to bind to GMP-agarose, but was able to bind the other reverse reaction substrate, inorganic pyrophosphate, with low affinity (K(d) of 4.7+/-0.1 mM). Dynamic light scattering and analytical gel filtration suggested that the enzyme exists as a homohexamer in solution.

Amperometric biosensor for xanthine with supramolecular architecture.

Xanthine oxidase modified with 1-adamantanyl residues was supramolecularly immobilized on Au electrodes coated with Au nanoparticles coated with a perthiolated beta-cyclodextrin polymer; the analytical response of the electrode toward xanthine was evaluated.

Assessment of the antioxidant activities of Brazilian extracts of propolis alone and in topical pharmaceutical formulations.

The antioxidant activity of extracts of propolis and of formulations added with these extracts were measured by scavenging different radicals in different systems. For the ethanolic extract of propolis (EEP) and the glycolic extract of propolis (GEP) the IC50 observed were respectively of 0.024 and 0.035 microL/mL in scavenging hydroxyl radical, 0.016 and 0.012 microL/mL in inhibiting lipid peroxidation, 0.22 and 0.24 microL/mL in inhibiting chemiluminescence produced in the H2O2/luminol/horseradish peroxide (HRP) system and about 0.005 microL/mL for both extracts in inhibiting chemiluminescence produced in the xanthine/luminol/xanthine oxidase (XOD) system. The antioxidant activity of extracts of propolis in the formulations was not able to be assessed neither using the deoxyribose assay, since the formulation components interfered in the assay measurements, nor using chemiluminescence in the H2O2/luminol/HRP system, since this method did not show to be sensitive for the extract of propolis evaluation. However, the antioxidant activity of extracts of propolis could be successfully evaluated in the formulations using both lipid peroxidation and chemiluminescence generated in the xanthine/luminol/XOD system inhibitions.

Deactivation of triplet-excited riboflavin by purine derivatives: important role of uric acid in light-induced oxidation of milk sensitized by riboflavin.

The reactivity of purine derivatives (uric acid, xanthine, hypoxanthine, and purine) toward triplet-excited riboflavin in aqueous solution at pH 6.4 is described on the basis of kinetic (laser flash photolysis), electrochemical (square-wave voltammetry), and theoretical data (density functional theory, DFT). Direct deactivation of triplet-excited riboflavin in aqueous solution, pH 6.4 at 24 degrees C, in the presence of uric acid, xanthine, and hypoxanthine strongly suggests a direct electron transfer from the purine to the triplet-excited riboflavin with k = 2.9 x 10(9) M(-1) s(-1) (DeltaH(++) = 14.7 kJ mol(-1), DeltaS(++) = -15.6 J mol(-1) K(-1)), 1.2 x 10(9) M(-1) s(-1) (DeltaH(++) = 34.3 kJ mol(-1), DeltaS(++) = +45.3 J mol(-1) K(-1)), and 1.7 x10(8) M(-1) s(-1) (DeltaH(++) = 122 kJ mol(-1), DeltaS(++) = +319 J mol(-1) K(-1)), respectively. From the respective one-electron oxidation potentials collected in aqueous solution at pH 6.4 for uric acid (E = +0.686 vs normal hydrogen electrode, NHE), xanthine (E = +1.106 vs NHE), and hypoxanthine (E = +1.654 vs NHE), the overall free energy changes for electron transfer from the quencher to the triplet-excited riboflavin are as follows: uric acid (DeltaG(o) = -114 kJ mol(-1)), xanthine (DeltaG(o) = -73.5 kJ mol(-1)), hypoxanthine (DeltaG(o) = -20.6 kJ mol(-1)), and purine (DeltaG(o) > 0). The inertness observed for purine toward triplet-excited riboflavin corroborates with its electrochemical inactivity in the potential range from 0 up to 2 V vs NHE. These data are in agreement with the DFT results, which show that the energy of the purine highest occupied molecular orbital (HOMO) (-0.2685 arbitrary unit) is lower than the energy of the semioccupied molecular orbital (SOMO) (-0.2557 a.u.) of triplet-excited riboflavin, indicating an endergonic process for the electron-transfer process. The rate-determining step for deactivation by purine derivatives can be assigned to an electron transfer from the purine derivative to the SOMO orbital of the triplet-excited riboflavin. The results show that uric acid may compete with oxygen and other antioxidants to deactivate triplet-excited riboflavin in milk serum and other biological fluids leading to a free radical process.

Reactive oxygen species induce different cell death mechanisms in cultured neurons.

Apoptosis is characterized by chromatin condensation, phosphatidylserine translocation, and caspase activation. Neuronal apoptotic death involves the participation of reactive oxygen species (ROS), which have also been implicated in necrotic cell death. In this study we evaluated the role of different ROS in neuronal death. Superoxide anion was produced by incubating cells with xanthine and xanthine oxidase plus catalase, singlet oxygen was generated with rose Bengal and luminic stimuli, and hydrogen peroxide was induced with the glucose and glucose oxidase. Cultured cerebellar granule neurons died with the characteristics of apoptotic death in the presence of superoxide anion or singlet oxygen. These two conditions induced caspase activation, nuclear condensation, phosphatidylserine translocation, and a decrease in intracellular calcium levels. On the other hand, hydrogen peroxide led to a necrosis-like cell death that did not induce caspase activation, phosphatidylserine translocation, or changes in calcium levels. Cell death produced by both singlet oxygen and superoxide anion, but not hydrogen peroxide, was partially reduced by an increase in intracellular calcium levels. These results suggest that formation of specific ROS can lead to different molecular cell death mechanisms (necrosis and apoptosis) and that ROS formed under different conditions could act as initiators or executioners on neuronal death.

Inhibition of Na+, K+-ATPase activity in rat striatum by the metabolites accumulated in Lesch-Nyhan disease.

In the present study, we investigated the in vitro effect of hypoxanthine, xanthine and uric acid, metabolites accumulating in tissue of patients with Lesch-Nyhan disease, on Na(+), K(+)-ATPase activity in striatum of neonate rats. Results showed that all compounds significantly inhibited Na(+), K(+)-ATPase activity. We also studied the kinetics of the inhibition of Na(+), K(+)-ATPase activity caused by hypoxanthine. The apparent K(m) and V(max) of Na(+), K(+)-ATPase activity for ATP as the substrate and hypoxanthine as the inhibitor were 0.97 mM and 0.69 nmol inorganic phosphate (Pi) released per min per mg of protein, respectively. K(i)-value was 1.9 microM, and the inhibition was of the non-competitive type. We also observed that the inhibitory effects of hypoxanthine, xanthine and uric acid probably occur through the same mechanism, suggesting a common binding site for these oxypurines on Na(+), K(+)-ATPase. Therefore, it is conceivable that inhibition of brain Na(+), K(+)-ATPase activity may be involved at least in part in the neuronal dysfunction characteristic of patients with Lesch-Nyhan disease.

Metalloproteinase 2 activity and modulation in uterus from neonatal streptozotocin-induced diabetic rats during embryo implantation.

Matrix metalloproteinases (MMPs) are responsible for the remodelling of the uterine extracellular matrix during embryo implantation. Nitric oxide (NO) production is increased at the time when implantation begins. Abnormal tissue levels of MMPs are present in diabetes; elevated NO levels in tissues and an increased oxidative stress are also found. The present work evaluates the uterine MMP2 activity and levels during embryo implantation, as well as the influence of nitridergic compounds and reactive oxygen species (ROS) on the MMP2 enzymatic activity in a model of neonatal streptozotocin-induced diabetic rat. Metalloproteinase 2 activity and levels are increased in diabetic tissues compared with controls (P < 0.05 and P < 0.002 respectively). The uterine enzymatic activity in diabetic animals decreases in the presence of the NOS inhibitor NG-nitro-L-arginine methyl ester (P < 0.01) and is enhanced (P < 0.005) when a generating ROS system (xanthine/xanthine oxidase) is added to the incubating medium. It was also found that uterine superoxide dismutase activity is higher in diabetic rats than in control rats on the day of implantation (P < 0.001), suggesting a compensatory antioxidant ability. In conclusion, the results show that the uterine MMP2 activity, which is higher in diabetic animals than in control animals, is modulated positively by NO and ROS during embryo implantation in a model of streptozotocin-induced diabetic rats.

Rat ventral prostate xanthine oxidase bioactivation of ethanol to acetaldehyde and 1-hydroxyethyl free radicals: analysis of its potential role in heavy alcohol drinking tumor-promoting effects.

The ability of the ventral prostate cytosolic fractions to biotransform ethanol to acetaldehyde and 1-hydroxyethyl (1HEt) radicals was tested. Acetaldehyde formation was determined by GC-FID analysis in the head space of incubation mixtures. 1HEt was determined by spin trapping with PBN followed by extraction, silylation of the adduct and GC-MS of the product. Prostate cytosol was able to biotransform ethanol to acetaldehyde in the presence of NADH, hypoxanthine, xanthine, caffeine, theobromine, theophylline, and 1,7-dimethylxanthine but not in the presence of N-methylnicotinamide. All these biotransformations were inhibited by allopurinol and were sensitive to heating for 5 min at 100 degrees C. The biotransformation of ethanol to acetaldehyde in the presence of purines as cosubstrates was accompanied by the formation of hydroxyl and 1HEt radicals as detected by GC-MS, and the process was inhibited by allopurinol. Results suggest that prostate cytosolic xanthine oxidase is able to bioactivate ethanol to acetaldehyde and free radicals. The potential of these processes to be involved in tumor-promoting effects of heavy alcohol drinking in conjunction with high meat and/or purines consumption is analyzed. Multifactorial epidemiological studies considering that possibility might be convenient. Teratogenesis Carcinog. Mutagen. 21:109-119, 2001.