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Journal Article 2016; 37(Suppl 1): 132-138 PubMed PMID: 28263541 Citation  Keywords:  Biological Assay:methods, Biosensing Techniques:methods, Blood Glucose:metabolism, Enzymes, Immobilized:metabolism, Glucose Oxidase:metabolism, Horseradish Peroxidase:metabolism, Humans, Smartphone:utilization,.   

<strong>OBJECTIVES:strong> Glucose is an important diagnostic biochemical marker of diabetes but also for organophosphates, carbamates, acetaminophens or salicylates poisoning. Hence, innovation of accurate and fast detection assay is still one of priorities in biomedical research.

<strong>METHODS:strong> Glucose sensor based on magnetic particles (MPs) with immobilized enzymes glucose oxidase (GOx) and horseradish peroxidase (HRP) was developed and the GOx catalyzed reaction was visualized by a smart-phone-integrated camera.

<strong>RESULTS:strong> Exponential decay concentration curve with correlation coefficient 0.997 and with limit of detection 0.4 mmol/l was achieved. Interfering and matrix substances were measured due to possibility of assay influencing and no effect of the tested substances was observed. Spiked plasma samples were also measured and no influence of plasma matrix on the assay was proved.

<strong>CONCLUSIONS:strong> The presented assay showed complying results with reference method (standard spectrophotometry based on enzymes glucose oxidase and peroxidase inside plastic cuvettes) with linear dependence and correlation coefficient 0.999 in concentration range between 0 and 4 mmol/l. On the grounds of measured results, method was considered as highly specific, accurate and fast assay for detection of glucose.

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Journal Article 2016; 37(Suppl 1): 123-131 PubMed PMID: 28263540 Citation  Keywords:  Benzhydryl Compounds:metabolism, Biological Assay, Cell Line, Endocrine Disruptors:metabolism, Estrogen Receptor alpha:agonists, Estrogens, Non-Steroidal:metabolism, Humans, Phenols:metabolism,.   

OBJECTIVES:&nbsp;The aim of this study was to compare in silico data with results obtained in two alternative in vitro methods; and to investigate the potential endocrine activity of bisphenol A analogues. This article contributes to recent findings and brings up-to-date information on development of EU legislation and in vitro testing methods of endocrine disruption.

METHODS:&nbsp;In silico approach based on the OECD QSAR Toolbox was used for prediction of potential ligands of human estrogen receptor α. Estrogen Receptor Transactivation in vitro Assay to Detect Estrogen Receptor Agonists and Antagonists (OECD TG 455/457) using the VM7Luc4E2 (formerly designated BG1Luc4E2) cell line was performed for measurement of transactivation activity of the tested substances. Commercially available yeast-based microplate assay (XenoScreen YES/YAS, Xenometrix, Switzerland) for detection of compounds with estrogenic and androgenic agonistic/antagonistic activity was used as a comparative test to estrogen receptor transactivation assay (OECD TG 455/457) and for screening of the agonistic/antagonistic potential of human estrogen receptor and agonistic/antagonistic activity of tested compounds on human androgen receptor.

RESULTS:&nbsp;The study showed good correlation between the two in vitro assays and significant correlation with in silico data. All tested substances were identified as agonists for human estrogen receptor α by methods in silico and in vitro, four substances showed a potentially higher estrogenic activity comparing to bisphenol A, two substances were identified as very weak antagonists of human androgen receptor and one compound showed a potential of agonistic activity to human androgen receptor.

CONCLUSIONS:&nbsp;The study contributes to recent findings and brings new in silico and in vitro data of bisphenol A analogues, revealing that these analogous substances should be further tested as they may show similar or higher activity in vivo comparing to bisphenol A, which has been recently legislatively regulated....

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Journal Article 2016; 37(Suppl 1): 118-122 PubMed PMID: 28263539 Citation  Keywords:  Acetylcholinesterase:drug effects, Celecoxib:pharmacology, Cholinesterase Inhibitors:pharmacology, Cyclooxygenase 2 Inhibitors:pharmacology, Dithionitrobenzoic Acid, Humans, Molecular Docking Simulation,.   

<strong>OBJECTIVES:strong> Celecoxib is a nonsteroidal anti-inflammatory drug inhibiting enzyme cyclooxygenase-2 (COX-2). The drug was introduced in 1990s. In the work presented here, affinity of celecoxib to enzyme acetylcholinesterase (AChE) is inferred.

<strong>METHODS:strong> Inhibition of human AChE by celecoxib was tested using standard spectrophotometric Ellman´s method and extrapolation of experimental data by Dixon plot. Interaction between AChE and celecoxib was also predicted by molecular docking using Swiss dock software.

<strong>RESULTS:strong> A non-competitive mechanism of inhibition was revealed and equilibrium inhibitory constant equal to 313±40 µmol/l was determined. Comparing to AChE, celecoxib was not proved as an inhibitor of enzyme butyrylcholinesterase (BChE). The lowest ΔG was equal to -7.78 kcal/mol. In this case, celecoxib stacked sulfonamide moiety between TYR 337 and TYR 341 of alfa anionic subsite of active site. Cation-Π interactions appears to be responsible for the inhibition.

<strong>CONCLUSIONS:strong> Though the here revealed and characterized inhibition has lower effect in real conditions than inhibition of COX-2, the inhibitory effect would be utilized in the next research and development of new AChE inhibitors.

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Journal Article 2016; 37(Suppl 1): 111-117 PubMed PMID: 28263538 Citation  Keywords:  Animals, Disease Models, Animal, Evoked Potentials, Hippocampus:drug effects, Lysosomes:drug effects, Male, Neurodegenerative Diseases:chemically induced, Neurons:physiology, Rats, Rats, Wistar, Trimethyltin Compounds:administration & dosage,.   

<strong>OBJECTIVES:strong> Extensive effort has been made to identify early markers of neurodegeneration as late stages have no chance of treatment. Recently, many experimental models have been used to study hallmarks of neuronal injury. One of them is the model of trimethyltin (TMT)-induced damage associated with cognitive decline, thus called a model of Alzheimer-like disease.

<strong>OBJECTIVE AND METHODS:strong> Our aim was to study neuronal transmission in hippocampal slices of male Wistar rats affected with a single dose of TMT (7.5 mg/kg, i.p.) during the first three weeks of its action. The monitored time periods after TMT administration were days 1-3; 8-10 and 15-17. At the same time periods, right hippocampi were collected for determination of changes in specific activities of two lysosomal enzymes. Electrophysiological measurements were based on stimulation of Schäffer collaterals and registration of evoked responses in the stratum pyramidale and the stratum radiatum at the CA3-CA1 synapse. Specific activities of N-acetyl-β-D-glucosaminidase (NAGA) and cathepsin D (Cat D) were determined spectrophotometrically.

<strong>RESULTS:strong> During three weeks after i.p. TMT administration to rats, we found a time-dependent reduction of postsynaptic neuronal firing, expressed by diminished population spike (PoS) amplitude recorded in the stratum pyramidale accompanied with marked increase in specific activity of NAGA to respective 111%, 163% and 252% in the 1st, 2nd and 3rd week compared to unaffected rats. In the stratum radiatum, reduction of the slope of excitatory postsynaptic potential was not time-dependent but almost constantly reduced from the 1st to 3rd week after TMT administration (55-60%) compared to control rats. Specific activity of lysosomal enzyme Cat D was significantly increased in the 3rd week after TMT administration.

<strong>CONCLUSION:strong> This work demonstrates a time-dependent reduction of somatic response in the hippocampus of TMT affected rats during the first three weeks. This reduction of neuronal firing was later accompanied with increase of specific activity of NAGA and Cat D, supporting evidence that lysosomal dysfunction may be one of the primary contributors to TMT-induced neurodegeneration.

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Journal Article 2016; 37(Suppl 1): 103-110 PubMed PMID: 28263537 Citation  Keywords:  Animals, Anxiety:physiopathology, Behavior, Animal:physiology, Corticosterone:blood, Depression:physiopathology, Disease Models, Animal, Male, Rats, Rats, Wistar, Stress, Psychological:blood,.   

<strong>OBJECTIVES:strong> There are several models of depression. Chronic unpredictable mild stress (CMS) appears to have the greatest validity, although it is often being criticized for low reliability.

<strong>METHODS:strong> Male Wistar/DV rats were used in this study to assess our modified 2-week model of CMS as a combination of psychosocial, physical and metabolic stressors and to compare the effect of acute administration of venlafaxine (VFX) and diazepam (DZP), either in stress or no stress conditions. The animals were exposed to one particular stressor each day. The time of day and duration of the stressor differed across the procedure to avoid animals to adapt to the stress stimulus. After cessation of stress, the animals underwent the following behavioral tests to assess motor activity, cognition, anxiety- and depression-like behavior: Open field test, Elevated plus maze, Forced swim test, Stress-iduced hyperthermia, Light/dark test and Y maze. To assess hypothalamic-pituitary-adrenal axis (HPA) reactivity in our CMS model, plasma corticosterone levels were measured 24 h after termination of stress.

<strong>RESULTS:strong> Corticosterone levels were significantly increased compared to control values (p<0.05) in our experimental schedule of CMS. Our paradigm produced delayed anxiety-like behavior observed in Open field (decreased time spent in central zone 3 weeks after CMS, p<0.05), with anxiolytic effect of CMS shortly after its cessation. Stressed animals spent more time in the open arms of Elevated plus maze (p<0.05) and travelled longer distance in the light zone of the Light/dark box (p<0.01). CMS did not increase the behavioral despair analyzed in Forced swim test yet it disrupted the capacity of the Stress-induced hyperthermia test (CMS rats failed to react to the stress by increasing the core temperature).

<strong>CONCLUSIONS:strong> Based on our results, we can conclude that our CMS protocol leads to increased corticosterone levels as a result of HPA axis hyperactivity and produces delayed onset of anxiogenic behavior. Moreover, CMS exerted a substantial effect on the behavioral outputs, interfering with drug testing.

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Journal Article 2016; 37(Suppl 1): 95-102 PubMed PMID: 28263536 Citation  Keywords:  Antineoplastic Agents, Phytogenic:metabolism, Cytochrome P-450 CYP3A:metabolism, DNA Adducts:metabolism, Ellipticines:metabolism, Humans, Liposomes, Microsomes,.   

<strong>OBJECTIVES:strong> Ellipticine is an anticancer agent that functions through multiple mechanisms participating in cell cycle arrest and initiation of apoptosis. This drug forms covalent DNA adducts after its enzymatic activation with cytochrome P450 (CYP), which is one of the most important ellipticine DNA-damaging mechanisms of its cytotoxic effects. The improvements of cancer treatment are the major challenge in oncology research. Nanotransporters (nanoparticles) are promising approaches to target tumor cells, frequently leading to improve drug therapeutic index. Ellipticine has already been prepared in nanoparticle forms. However, since its anticancer efficiency depends on the CYP3A4-mediated metabolism in cancer cells, the aim of our research is to develop nanoparticles containing this enzyme that can be transported to tumor cells, thereby potentiating ellipticine cytotoxicity.

<strong>METHODS:strong> The CYP3A4 enzyme encapsulated into two nanoparticle forms, liposomes and microsomes, was tested to activate ellipticine to its reactive species forming covalent DNA adducts. Ellipticine-derived DNA adducts were determined by the 32P-postlabeling method.

<strong>RESULTS:strong> The CYP3A4 enzyme both in the liposome and microsome nanoparticle forms was efficient to activate ellipticine to species forming DNA adducts. Two DNA adducts, which are formed from ellipticine metabolites 12-hydroxy- and 13-hydroxyellipticine generated by its oxidation by CYP3A4, were formed by both CYP3A4 nanoparticle systems. A higher effectiveness of CYP3A4 in microsomal than in liposomal nanoparticles to form ellipticine-DNA adducts was found.

<strong>CONCLUSION:strong> Further testing in a suitable cancer cell model is encouraged to investigate whether the DNA-damaging effects of ellipticine after its activation by CYP3A4 nanoparticle forms are appropriate for active targeting of this enzyme to specific cancer cells.

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Journal Article 2016; 37(Suppl 1): 84-94 PubMed PMID: 28263535 Citation  Keywords:  Animals, Benzo(a)pyrene:pharmacology, Cytochrome P-450 Enzyme System:metabolism, Endocrine Disruptors:pharmacology, Estradiol:pharmacology, Estrogens:pharmacology, Ethinyl Estradiol:pharmacology, Male, Microsomes, Liver:metabolism, Rats, Rats, Wistar,.   

OBJECTIVES:&nbsp;The term "endocrine disruptor" (ED) is used for compounds that mimic or antagonize the effects of endogenous hormones. Synthetic estrogen 17α-ethinylestradiol (EE2) and a human carcinogen benzo[a]pyrene (BaP) are assigned as exogenous endocrine disruptors and an estrogenic hormone estradiol is a natural endogenous disruptor. Here, the potency of these three disruptors administered to rats individually and in combination to induce expression of cytochrome P450 (CYP) enzymes involved in their own metabolism (CYP1A1, 2C and 3A) in vivo was investigated.

METHODS:&nbsp;Changes in CYP protein expression after exposure of rats to BaP, EE2 or estradiol were analyzed by Western blotting. Using the HPLC method, CYP1A1, 2C and 3A specific activities in hepatic microsomes isolated from exposed rats were analyzed.

RESULTS:&nbsp;Whereas exposure to BaP induces expression of CYP1A1 protein and its marker activity (Sudan I oxidation) in liver, kidney and lung of rats, no significant induction of this CYP and its enzyme activity was produced by EE2 and estradiol. Treatment of BaP in combination with EE2 and/or estradiol decreased the BaP-mediated CYP1A1 induction in liver of exposed rats. BaP also induces CYP2C11 protein in rat liver and kidney, but does not increase its enzyme activity measured as testosterone 16α-hydroxylation. The enzyme activity of another enzyme of the 2C subfamily, CYP2C6, diclofenac 4'-hydroxylation, is even decreased by BaP. The CYP2C11 protein expression and/or its activity are also increased in liver of rats treated with EE2 and estradiol, but its expression is significantly decreased in lung. The CYP2C6 activity is also elevated by treatment of rats with EE2 and estradiol administered individually as well as in their combination. Whereas only a slight increase in CYP3A protein expression was found by BaP in rat liver, its enzyme activity, testosterone 6β-hydroxyalation, increased significantly in this organ. In contrast, no effect or even a decrease in CYP3A expression and its enzyme activity was produced by EE2 and estradiol in rats exposed to these compounds....

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Journal Article 2016; 37(Suppl 1): 78-83 PubMed PMID: 28263534 Citation  Keywords:  Analgesics:toxicity, Animals, Cytotoxins:toxicity, Deer, Heart:drug effects, Ketamine:analogs & derivatives, Kidney:cytology, Liver:cytology, Toxicity Tests:methods, Xylazine:analogs & derivatives,.   

<strong>OBJECTIVES:strong> Chemical restraint of wild animals is practiced to accomplish intended procedures such as capture, clinical examination, collection of diagnostic samples, treatment and/or transport. Extra-label use of animal medicinal drugs is often necessary in wildlife because most approved therapeutics do not list wild species on the labelling. Here, we used cellular in vitro models, a cutting-edge tool of biomedical research, to examine cytotoxicity of anaesthetic agents in fallow deer and extrapolate these data for anaesthetic risks in wildlife.

<strong>METHODS:strong> We examined the cytotoxic effects of ketamine, xylazine, and ketamine-xylazine, i.e. the Hellabrunn mixture, on liver-, heart- and kidney-derived cell cultures prepared from a fallow deer (Dama dama) specimen. In line with preliminary studies we exposed cells to 10 µM, 50 µM, 100 µM, 1 mM, and 10 mM ketamine or xylazine. The combination of ketamine-xylazine was dosed at 0.025+0.02 mg/ml, 0.05+0.04 mg/ml, 0.75+0.06 mg/ml, 0.1+0.08 mg/ml, and 0.125+0.1 mg/ml per one well containing 10 000 cells. The quantification of cytotoxicity was based on lactate dehydrogenase activity released from damaged cells.

<strong>RESULTS:strong> Liver-derived cells show higher sensitivity to the cytotoxic effects of both ketamine and xylazine administered as single drugs when compared with cells cultured from the heart and kidney. The Hellabrunn mixture induced significantly higher cytotoxicity for kidney-derived cells ranging from 16.78% to 35.6%. Single and combined exposures to ketamine and xylazine resulted only in high-dose cytotoxicity in the heart-derived cells.

<strong>CONCLUSIONS:strong> Our results indicate that immobilization drugs significantly differ in their cytotoxic effects on cells derived from various organs of the fallow deer.

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