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Journal Article 2008; 29(5): 599-608 PubMed PMID: 18987583 Citation  Keywords:  Animals, Animals, Wild, Ecosystem, Environmental Pollutants:analysis, Fluorocarbons:analysis, Fresh Water, Humans, Risk Assessment,.   

: Perfluorinated compounds (PFCs) such as perfluoro-octane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) are emerging environmental pollutants, arising mainly from their use as surface treatment chemicals, polymerization aids and surfactants. They are ubiquitous, persistent and bioaccumulative in the environment. Perfluorinated compounds are being proposed as a new class of POPs. Although tests in rodents have demonstrated numerous negative effects of PFCs, it is unclear if exposure to perfluorinated compounds may affect human health. This review provides an overview of the recent toxicology and toxicokinetics, monitoring data now available for the environment, wildlife, and humans and attempts to explain the mechanisms of action of PFCs....

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Journal Article 2008; 29(5): 749-754 PubMed PMID: 18987582 Citation  Keywords:  Acetamides, Calibration, Fluoroacetates, Gas Chromatography-Mass Spectrometry, Humans, Pharmaceutical Preparations:blood, Reproducibility of Results, Solid Phase Extraction, Substance Abuse Detection:methods, Substance-Related Disorders:blood, Trifluoroac.   

OBJECTIVES: The purpose of this study is to develop the gas chromatographic-mass spectrometric method (GC-MS) for screening and semiquantification of drugs and drugs of abuse in human serum.

METHOD: GC-MS method after liquid-liquid extraction (LLE) and derivatization with N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) is presented for screening as well as identification and semiquantification of the most frequently used drugs and drugs of abuse in human serum.

RESULTS: Bovine serum spiked with ephedrine (EPHE), 3,4-methylenedioxymethamphetamine (MDMA), guaifenesin (GUAIF), tramadol (TRAM), phenobarbital (PHENO), amitriptyline (AMITR), cocaine (COCA), mirtazapine (MIRTA), dothiepin (DOTH), citalopram (CITAL), clomipramine (CLOMI), bromazepam (BMZPM), diazepam (DZPM), codeine (COD), morphine (MORPH), levomepromazine (LEVO), zolpidem (ZOLP), clozapine (CLOZP), alprazolam (ALPZM) was used for the recovery and repeatability study and for preparation of calibration curves of individual compounds or their TMS derivatives. Recoveries were tested on concentration levels 0.05, 0.1 and 0.5 microg/mL (n=6) and established in range 72.0-98.0%. Repeatabilities expressed as relative standard deviations (RSDs) measured at concentration levels 0.05, 0.1 and 0.5 microg/ mL (n=6) were lower than 10.0%. The calibration curves for analytes or their TMS derivatives were linear in concentration range 0.025-2.000 microg/mL (except of EPHE 2TMS, MDMA TMS, MORPH 2TMS, BMZPM TMS, ALPZM) with correlation coefficients exceeding 0.99. The limit of quantification (LOQ) for analytes used for evaluation study was 0.025 microg/mL (except analytes mentioned above).

CONCLUSIONS: The GC-MS method presented here is allowing screening, identification and semiquantification of the most commonly encountered drugs and drugs of abuse in human serum and can be successfully applied to analysis of real samples from clinical and forensic toxicology cases....

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Journal Article 2008; 29(5): 722-727 PubMed PMID: 18987581 Citation  Keywords:  Adamantane:analogs & derivatives, Amino Acid Sequence, Animals, Arginine:genetics, Aryl Hydrocarbon Hydroxylases:antagonists & inhibitors, Chromatography, High Pressure Liquid, Crystallography, X-Ray, Cytochrome P450 Family 2, Enzyme Inhibitors:pharmacolo.   

OBJECTIVES: Understanding the enzyme mechanism of P450 enzymes needs a detailed knowledge of substrate-enzyme interactions. Here, we examined the interaction of cytochrome P450 2B4 with a diamantanoid substrate.

METHODS: The interaction was followed using a photoactivable label, 3-azidiamantane. After photochemically driven reaction, the labeled enzyme was cleaved by trypsine and the labeled peptides separated by HPLC and identified with the help of radioactivity (for tritiated label) and mass spectrometry. The results were analysed on the basis of the known X-ray structures for mammalian cytochromes P450.

RESULTS: Identification of labeled peptides has shown that the probe (binding as a substrate to the enzyme) was attached to fragments: 30-48 (the most likely positions of the label are Leu44, Gln45 and Asp47), 127-140 (with Arg133 labeled, as indicated by mass spectrometry), 359-373 and 434-443 (the exact position of the label unknown). The structural comparison indicates considerable differences in Arg133 interaction with heme propionates, connected with binding of the substrate. Labeling of this residue may thus reflect its involvement in modulation of cytochrome P450 activity.

CONCLUSION: The results show existence of additional binding sites for substrate on cytochrome P450 2B4, located close to the surface of the enzyme....

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Journal Article 2008; 29(5): 802-805 PubMed PMID: 18987580 Citation  Keywords:  Adenosine Triphosphate:metabolism, Antioxidants:pharmacology, Cell Survival:drug effects, Dose-Response Relationship, Drug, Humans, Luminescence, Neutrophils:drug effects, Reactive Oxygen Species:metabolism, Stilbenes:pharmacology, Structure-Activity Rela.   

OBJECTIVES: Oxidative stress is related to a number of autoimmune diseases, e.g. rheumatoid arthritis, cancer, etc. The main source of pathologically working reactive oxygen species (ROS) are activated polymorphonuclear leukocytes (PMNL).

OBJECTIVE: There are some papers comparing structure - pharmacological efficiency relationship of vegetal substances from the stilbenoid group. We compared the effect of trans-resveratrol, which is well-known by its antioxidative activity, with the effect of pinosylvin and pterostilbene.

METHODS: Luminol-enhanced chemiluminescence (CL) was used to study the antioxidative action. The effect was observed in whole blood and in isolated PMNL. The concentrations of substances tested were 0.01-100 microM. Due to the different abilities of luminol and isoluminol to pass through the cell membrane, we studied the effect of the substances tested on intracellular and extracellular ROS. To stimulate the production of ROS we used phorbol-myristate-acetate (PMA), which activates PMNL via protein kinase C.

RESULTS: Resveratrol, pinosylvin and pterostilbene inhibited significantly the CL of whole blood and extra- and intracellular CL of isolated PMNL in a dosedependent manner. Depending on different functional groups of the stilbene molecule, resveratrol inhibited CL of whole blood and isolated PMNL, whereas pinosylvin influenced mainly intracellular CL and pterostilbene extracellular CL.

CONCLUSION: The presence of different functional groups in the molecules of stilbenoids influence their antioxidative effect. Modification of these functional groups may result in derivatives with required antioxidative properties, targeting mainly extracellular ROS which are responsible for tissue damage during chronic inflammation....

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Journal Article 2008; 29(5): 697-701 PubMed PMID: 18987579 Citation  Keywords:  Antioxidants:chemistry, Ascorbic Acid:chemistry, Carbohydrate Sequence, Copper:chemistry, Free Radicals:chemistry, Hyaluronic Acid:chemistry, Hydrogen Peroxide:chemistry, Hydroxyl Radical:chemistry, Kinetics, Molecular Weight, Oxidants:chemistry, Penicill.   

OBJECTIVES: The study presents results of pro- and anti-oxidative effects of D-penicillamine on hyaluronan degradation by ascorbate plus cupric ions.

METHODS: The well established degradative system comprising high-molar-mass hyaluronan and ascorbate plus Cu(II) ions was used. Primarily, the effects of replacement of ascorbic acid in this system by D-penicillamine were investigated. Then, D-penicillamine was added into the above degradative system before reaction onset or 1h after the reaction had started. To monitor hyaluronan degradation kinetics, rotational viscometry was applied.

RESULTS: No hyaluronan degradation occurred when ascorbate was replaced by D-penicillamine. The drug addition into the complete degradative system at the reaction onset caused a marked inhibition of hyaluronan degradation. However, the inhibitory effect turned to a pro-oxidative one within appr. 1 h.

CONCLUSION: The dual behavior of D-penicillamine on hyaluronan degradation can relate to: (i) the drug completely traps *OH radicals generated from ascorbate plus Cu(II) ions under aerobic conditions; (ii) thiyl radicals generated from D-penicillamine react with D-penicillamine anions resulting in novel radical reactive species, which e.g. by reducing dioxygen molecules can generate further *OH radicals....

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Journal Article 2008; 29(5): 775-778 PubMed PMID: 18987578 Citation  Keywords:  Aldehyde Reductase:antagonists & inhibitors, Animals, Blotting, Western, Calcimycin:pharmacology, Cattle, Cell Line, Electrochemistry, Endothelial Cells:drug effects, Endothelium, Vascular:drug effects, Enzyme Inhibitors:pharmacology, Glucose:pharmacology.   

OBJECTIVES: An increased glucose utilization by aldose reductase (ALR-2) has been implicated in the pathogenesis of diabetic vascular complications. In this process, several mechanisms are involved, including the depletion of cofactors required for the action of antioxidant enzymes or endothelial NO synthase. In this study, the effect of a novel ALR-2 inhibitor JMC-2004 on hyperglycemia-induced endothelial dysfunction was studied.

METHODS: Bovine aortic endothelial cells (BAEC) were treated with glucose (30 mM), JMC-2004 (0.01mM), or glucose and JMC-2004 for 24 h. The cells were then stimulated with calcium ionophore A23187 after which NO production was measured electrochemically using a porphyrine-coated carbon NO electrode. Nitrite concentrations were determined in the cell supernatants. The peroxyl and hydroxyl radical-scavenging activity of JMC-2004 was measured with luminol-enhanced chemiluminescence. The expression of eNOS was determined by Western blotting. JMC-2004 IC50 for ALR-2 was determined colorimetrically with D-glyceraldehyde as a substrate.

RESULTS: Incubating the cells with 30 mM glucose strongly diminished A23187- induced NO production. Treatment with JMC-2004 restored NO production by 40% without affecting eNOS expression. This effect was probably antioxidantindependent, since JMC-2004 did not have any antioxidant capacity. JMC-2004 exerted high selectivity towards ALR-2.

CONCLUSIONS: ALR-2 inhibition with JMC-2004 was able to abolish hyperglycemia- induced endothelial dysfunction in bovine aortic endothelial cells....

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Journal Article 2008; 29(5): 759-762 PubMed PMID: 18987577 Citation  Keywords:  Acetylcholinesterase:metabolism, Animals, Biosensing Techniques, Butyrylcholinesterase:metabolism, Cholinesterase Inhibitors:pharmacology, Methacholine Chloride:pharmacology, Muscarinic Agonists:pharmacology, Oximes, Parasympathetic Nervous System:drug ef.   

OBJECTIVES: The current standard treatment of organophosphate poisoning consists of an administration of anticholinergic drugs and cholinesterase reactivators (oximes). Oximes can react - except their reactivating effect on cholinesterases - directly with cholinoreceptors. HI-6 is an oxime that may have an inhibitory effect on the muscarinic receptors, too.

METHODS: In our work, we have investigated an influence of HI-6 on the acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and on the muscarinic receptors in vitro. The study was conducted using biosensor technique and on the rat bladder using in vitro test (tissue bath; methacholine as muscarinic agonist). IC50 for BChE from human serum was determined to be 1.01x10-6 M and for human erythrocytes AChE 3.31x10-6 M, respectively.

CONCLUSION: We assume that the demonstrated contractile response can be attributed to the inhibition of the AChE at the lower concentration and to a predominant inhibition of muscarinic receptor at higher concentration of compound tested....

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Journal Article 2008; 29(5): 653-657 PubMed PMID: 18987576 Citation  Keywords:  Adenomatous Polyposis Coli:epidemiology, Adenomatous Polyposis Coli Protein:genetics, Chromatography, High Pressure Liquid, DNA:biosynthesis, Gene Deletion, Mutation, Polymorphism, Single-Stranded Conformational:genetics, Reverse Transcriptase Polymerase .   

OBJECTIVES: The adenomatous polyposis coli (APC) gene was analyzed for germline mutations in 113 familial adenomatous polyposis suspected families from all over Slovakia. Mutation screening was performed using single strand conformation polymorphism (SSCP) and DNA sequencing.

RESULTS: Mutations in the APC gene were found in 39 (34.5%) Slovak families and 25 different pathogenic mutations throughout the APC gene were identified. Of these, 12 mutations were deletion, one was insertion and 12 were base substitution.

CONCLUSIONS: Molecular diagnostics of Slovak FAP families revealed broad palette of mutations in crucial APC gene. The patients with identified APC gene mutations were assigned to a specific therapeutic FAP program....

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