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Journal Article 2008; 29(5): 784-789 PubMed PMID: 18987608 Citation  Keywords:  Acetylcholine:metabolism, Animals, Blood Pressure:drug effects, Body Weight:drug effects, Cardiovascular Physiological Phenomena:drug effects, Enzyme Inhibitors:pharmacology, Feedback, Physiological:drug effects, Hypertension:drug therapy, Isometric Contr.   

OBJECTIVES: The effect of 8-week-lasting low-dose treatment of NG-Nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, was investigated in borderline hypertensive rats (BHR) to examine, whether dose of 1.5 mg/kg/day affects feedback regulation of NO synthesis.r />r /> METHODS: Blood pressure (BP) of 12 weeks old Wistar and BHR rats was determined non-invasively by tail-cuff. NO synthase (NOS) activity was determined by conversion of [3H]-L-arginine to [3H]-L-citrulline in the aorta, left ventricle (LV) and hypothalamus. Vascular function of the femoral artery was determined using Mulvany's myograph in isometric conditions.r />r /> RESULTS: Chronic low-dose L-NAME treatment of BHR induced sustained blood pressure elevation and left ventricular hypertrophy associated with the decrease in NOS activity in left ventricle and unaltered NOS activity in the aorta. By contrast, the improvement of LV and aortic NOS activity was found in Wistar rats. In hypothalamus, no changes in NOS activity were found in both BHR and Wistar. In Wistar, acetylcholine-induced relaxation of the femoral artery was increased and serotonin-induced and noradrenalin-induced constriction were reduced in L-NAME treated group. These effects, however, were not seen in BHR.r />r /> CONCLUSION: The results indicate that NOS/NO feedback regulation works differently under conditions of normotension and prehypertension. Low-dose L-NAME treatment accentuated NO production in normotensive rats, but it failed to improve NOS activity in BHR....

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Comparative Study 2008; 29(5): 680-684 PubMed PMID: 18987607 Citation  Keywords:  Anesthetics:toxicity, Animals, Clove Oil:toxicity, Ethylene Glycols:toxicity, Larva, Lethal Dose 50, Plant Oils:toxicity, Syzygium:toxicity, Temperature, Zebrafish:physiology,.   

OBJECTIVES: Anaesthetics are used in aquaculture to prevent stress and mechanical damage to fish during handling or the treatment of fish in breeding, blood sampling and other veterinary interventions. Clove oil and 2-phenoxyethanol are used in the Czech Republic in a water bath for the short-term immobilization of the fish.r />r /> DESIGN: Acute toxicity tests were performed on aquarium fish Danio rerio, which is considered to be one of the model organisms most commonly used in toxicity testing. The semi-static method according to OECD No. 203 (Fish acute toxicity test) was used for testing juvenile fish. Embryo toxicity tests were performed in zebrafish embryos (D. rerio) in compliance with the OECD No. 212 methodology (Fish, short-term toxicity test on embryo and sac-fry stages). The results obtained (the number of dead individuals at particular test concentrations) were subjected to a probit analysis using the EKO-TOX 5.2 programme in order to determine LC50 clove oil and 2-phenoxyethanol values. The statistical significance of the difference between LC50 values in juvenile and embryonic stages of D. rerio was tested using the Mann-Whitney non-parametric test implemented in the Unistat 5.1 programme.r />r /> RESULTS: The LC50 clove oil mean value was 18.8 +/- 5.52 mg.L-1 in juvenile D. rerio, and 15.64 +/- 3.30 mg.L-1 in embryonic stages of D. rerio. The LC50 2-phenoxyethanol mean value was 338.22 +/- 15.22 mg.L-1 in juvenile D. rerio, whereas in embryonic stages of D. rerio it was 486.35 +/- 25.53 mg.L-1.r />r /> CONCLUSIONS: The study proved statistically significantly higher (p<0.01) sensitivity in juvenile fish to 2-phenoxyethanol compared to the embryonic stages. Acute toxicity values of clove oil for juvenile and embryonic stages were comparable....

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Journal Article 2008; 29(5): 798-801 PubMed PMID: 18987606 Citation  Keywords:  Animals, Arrhythmias, Cardiac:genetics, Connexin 43:biosynthesis, Connexins:metabolism, Electrocardiography, Female, Immunohistochemistry, Male, Microscopy, Fluorescence, Myocardium:metabolism, Rats, Rats, Inbred SHR, Rats, Wistar, Sex Characteristics,.   

OBJECTIVES: To elucidate gender-related differences in occurrence of sudden cardiac death the myocardial connexin-43 (Cx43) and the susceptibility of male and female rat hearts to ventricular fibrillation (VF) were investigated.r />r /> METHODS AND RESULTS: Ventricular tissues taken from male and female normotensive Wistar and spontaneously hypertensive (SHR) rats were processed for immuno-fluorescence and immuno-blotting of Cx43. Susceptibility to ventricular fibrillation was examined in isolated heart preparation using either electrical stimulation or low K+ perfusion. Results showed that VF susceptibility of male either normotensive or hypertensive rats was significantly increased comparing to female counterparts. In correlation, ventricular expression of Cx43 was markedly lower in males of both normotensive and hypertensive rats comparing to females. SHR in addition exhibited abnormal myocardial Cx43 distribution due to structural remodelling.r />r /> CONCLUSIONS: Findings indicate that higher level of myocardial Cx43 expression is linked with lower lethal arrhythmia susceptibility and vice versa. It appears that Cx43 can be involved in sex-related differences in incidence of life-threatening arrhythmias....

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Journal Article 2008; 29(5): 631-634 PubMed PMID: 18987605 Citation  Keywords:  Adult, Anti-Infective Agents, Local:adverse effects, Anticonvulsants:adverse effects, Biological Availability, Boric Acids:adverse effects, Breast Feeding:adverse effects, Czech Republic, Drug Information Services:statistics & numerical data, Drug-Related.   

OBJECTIVES: The benefits of breastfeeding are generally accepted. Risk of drug usage for baby due to lactation is well assessed minimally in certain cases. However, information given about drugs are often insufficient, frustrating, and not recommending lactation. In Czech Teratology Information Service (CZTIS) counselling we use these information.r />r /> RESULTS: We have given advice in 58 cases inquiring the CZTIS about the risk of drug exposure during lactation. The most frequent queries were on chronic disease treatment following the drug exposure during pregnancy. Remaining cases were associated with acute infections. Mothers suffered from idiopathic bowel disease and psychiatric patients want to be informed before delivery about possibility to breastfeed their babies. Treatment of epilepsy, another frequent disease, is associated with better level of knowledge of both, neurologists and patients. Breastfeeding is recommended according to management in care of epileptic women.r />r /> CONCLUSION: In our counselling we consider the factors which are involved in drug transfer in the milk and mechanisms and steps of transfer as well. We follow the classification of drugs during lactation by their effect on infants: absolutely contraindicated, temporary cessation of breastfeeding, drugs of special concern and drugs compatible with breastfeeding....

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Journal Article 2008; 29(5): 779-783 PubMed PMID: 18987604 Citation  Keywords:  Adenosine Triphosphate:metabolism, Adrenergic beta-Antagonists:pharmacology, Carbazoles:pharmacology, Cell Differentiation:drug effects, Cell Proliferation:drug effects, Fluorometry, Granulocytes:drug effects, HL-60 Cells, Humans, Luminescence, Nitric Oxi.   

OBJECTIVES: The generation of reactive oxygen species (ROS) by phagocytes is one of the irreplaceable microbicidal tools of innate immunity. It has been reported in our previous studies that short-term treatment by carvedilol ex vivo inhibits ROS generation. The purpose of this study was to investigate the long-term effect of carvedilol on phagocytes.r />r /> METHODS: Human leukemia HL-60 cells differentiated into granulocyte-like cells were used as the model. Final concentrations of carvedilol were 0.1-100 micromol/l. The production of ROS by HL-60 cells was measured using luminol-enhanced chemiluminescence (CL).r />r /> RESULTS: Carvedilol in concentrations 0.1-10 micromol/l did not exhibit any toxic effect on cells (measured using bioluminescent bacteria Photorhabdus luminescens subsp. thracensis). One hour's treatment with 10 micromol/l carvedilol significantly decreased both spontaneous and activated CL of cells. Conversely, no inhibitory effects on CL were observed in 10 micromol/l carvedilol after 48 h incubation; lower concentrations of carvedilol even slightly increased the CL activity of HL-60 cells. A significant increase in spontaneous CL activity was detected in cells incubated with 10 micromol/l carvedilol in comparison with the control. Powerful antioxidative properties of carvedilol against peroxyl radical (ORAC assay) were proved. No scavenging of nitric oxide (electrochemical method) was observed.r />r /> CONCLUSIONS: Long-term influence of carvedilol can induce an increase in the generation of phagocyte-derived ROS and potentially also other inflammatory mediators. The increased ROS production is compensated for by antioxidative properties of carvedilol although the increased production of inflammatory mediators could affect the proper function of immune system....

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Journal Article 2008; 29(5): 794-797 PubMed PMID: 18987603 Citation  Keywords:  Animals, Diptera:physiology, Humans, Larva, Luminescence, Male, Neutrophils:drug effects, Peroxidase:metabolism, Salivary Glands:physiology, Superoxides:metabolism, Tissue Extracts:pharmacology, Zymosan,.   

OBJECTIVES: There is incomplete information about host immune response to maggot therapy, nowadays increasingly used to clean chronic wounds from necrotic debris and infection. Maggots are applied to the wound during the inflammatory phase. At the same time neutrophils infiltrate the inflammatory site as the first defense line of the organism. Myeloperoxidase (MPO) and reactive oxygen species, generated during the respiratory burst by neutrophils, are the key players participating in microbial killing as well as in signalling pathways.r />r /> AIM: We studied the effect of an extract from salivary glands (SGE) of Lucilia sericata (L. sericata) on opsonized zymosan stimulated whole blood chemiluminescence (CL), superoxide generation and MPO release from human neutrophils.r />r /> METHODS: Formation of reactive oxygen species in whole blood was determined by luminol-enhanced CL. superoxide generation was measured as superoxide dismutase inhibitable reduction of cytochrome c, MPO activity as the oxidation of o-dianisidine in the presence of hydrogen peroxide.r />r /> RESULTS: Crude SG extract of L. sericata had no significant effect either on superoxide generation and MPO release from isolated unstimulated human neutrophils or on activity of isolated enzymes. Crude SG extract of L. sericata in the highest concentration used significantly decreased opsonized zymosan (0.5 mg/ml) stimulated blood CL, superoxide generation and MPO release.r />r /> CONCLUSION: On the basis of our results as well as from the literature we suggest that the beneficial effects of maggot therapy might involve the decrease of generation and release of proinflammatory factors, while neither phagocytosis nor subsequent apoptosis is disturbed....

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Journal Article 2008; 29(5): 702-705 PubMed PMID: 18987602 Citation  Keywords:  Animals, Electric Stimulation, Excitatory Postsynaptic Potentials:physiology, Hippocampus:blood supply, Ischemic Attack, Transient:physiopathology, Long-Term Potentiation:physiology, Male, Rats, Rats, Wistar, Synaptic Transmission:physiology,.   

OBJECTIVES: Long-term potentiation (LTP) of neuronal activity in the hippocampus is thought to be a substrate for learning and memory. The influence of ischemia (IS) (hypoxia/hypoglycemia) on induction of LTP of synaptic transmission (ST) by high frequency stimulation (HFS) was investigated in rat hippocampal slices.r />r /> METHODS: Neurons were stimulated via Schäffer collaterals and field excitatory postsynaptic potentials (fEPSP) were recorded extracellularly from the CA1 region. LTP was induced by one single train (100 Hz, 1s).r />r /> RESULTS: In controls LTP of ST after HFS was 179.70+/-12.53%. Short IS of 2.5-4.5 min elicited a transient failure of ST, with return to former value followed by further increase of fEPSP amplitude to 142.28+/-16.24%, compared to amplitude before IS. HFS was elicited 40 min after exposure to IS and LTP was measured over further 40-60 min. LTP in slices exposed to 2.5-4.5-min IS was 139.94+/-14.01%. IS of 6-7.5 min elicited a prolonged failure of ST, with almost full recovery (96.69+/-14.42%). LTP was not activated 40 min after 6-7.5-min IS and the amplitude of fEPSP was even reduced to 80.14+/-19.19% compared to the former mean value of fEPSP 10 min before HFS.r />r /> CONCLUSION: The results revealed that prolonged 6-7.5-min IS influenced induction of LTP of ST in the hippocampus and thus it could have deleterious effects on learning and memory. These findings may have clinical implications in stroke, brain ischemia, sleep apnoe and call for studying the effect of neuroprotectants on the induction of LTP in hippocampus exposed to oxidative stress....

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Journal Article 2008; 29(5): 669-674 PubMed PMID: 18987601 Citation  Keywords:  Animals, Blood Cell Count, Carps:physiology, Cytochrome P-450 CYP1A1:metabolism, Cytochrome P-450 Enzyme System:metabolism, Erythrocyte Count, Herbicides:toxicity, Liver:drug effects, Triazines:toxicity, Vitellogenesis:drug effects, Water Pollutants, Chem.   

OBJECTIVES: Effects of metribuzin on biochemical and haematological indices, induction of specific biomarkers and impacts on biometric parameters of Cyprinus carpio were investigated for subchronic conditions.r />r /> METHODS: Juvenile fish were exposed to 0.175 mg.L-1 or 1.75 mg.L-1 metribuzin for 28 days. Haematological indices were assessed using unified methods of haematological examination in fish. Biochemical indices were determined by biochemical analyzer, hepatic vitellogenin content was estimated by direct sandwich ELISA. Cytochrome P450 concentration and ethoxyresorufin O-deethylase activity were measured in liver spectrophotometrically and spectrofluorimetrically, respectively.r />r /> RESULTS: Increased haematocrit and RBC count were found in fish exposed to 1.75 mg.L-1 metribuzin compared to control fish (p<0.05). Other indices contents and biomarkers levels were not significantly changed by either concentration of metribuzin.r />r /> CONCLUSION: Sublethal metribuzin pollution may have adverse impacts on haematological parameters in common carp....

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