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Journal Article 2010; 31(Suppl 2): 84-90 PubMed PMID: 21187824 Citation  Keywords:  Antioxidants:pharmacology, Apoptosis:drug effects, Caspase 3:metabolism, Cell Survival:drug effects, Computer Simulation, Dose-Response Relationship, Drug, Humans, In Vitro Techniques, Male, Neutrophils:cytology, Phosphorylation:drug effects, Protein Kina.   

OBJECTIVE: Pterostilbene, a naturally occurring phenolic derivative, exhibits various pharmacological effects, e.g. anti-cancerous, antioxidant, anti-inflammatory and anti-diabetic. Based on our previous study, we assessed the cellular and molecular effects of pterostilbene on human neutrophils and in cell free systems. Experimental and theoretical molecular descriptors of stilbene derivatives were also determined.

METHODS: We assessed the antioxidant properties of pterostilbene using cell free system and computational methods. The effect of pterostilbene on protein kinase C activation/phosphorylation was detected by special anti-phospho protein kinase C antibodies. Membrane associated changes determining the life span of neutrophils and human recombinant caspase-3 assay were examined.

RESULTS: Pterostilbene possessed comparable antioxidant properties as resveratrol in cell free system. Computational methods were used to establish the molecular characteristics of stilbene derivatives. The values of electronic parameters suggest a slight enhancement of electron donor properties of pterostilbene compared to resveratrol. Phosphorylation and thus activation of protein kinase C alpha/beta II in activated neutrophils was not decreased by pterostilbene. Pterostilbene in concentrations of 10-100 μM was found to inhibit the activity of human caspase-3 purified enzyme and did not influence cell viability significantly.

CONCLUSION: Pterostilbene, an analog of resveratrol, was identified as a good natural antioxidant compound. However, reducing the oxidative burst of human neutrophils during their activation in vitro with pterostilbene does not include protein kinase C phosphorylation pathway. Pterostilbene showed dose dependent activation/inhibition of caspase-3 enzyme activity....

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Journal Article 2010; 31(3): 343-347 PubMed PMID: 20588245 Citation  Keywords:  Alkenes:metabolism, Animals, Dose-Response Relationship, Drug, Female, Ferrous Compounds:pharmacology, Hydrogen Peroxide:pharmacology, In Vitro Techniques, Lipid Peroxidation:drug effects, Malondialdehyde:metabolism, Ovary:drug effects, Swine,.   

OBJECTIVE: Substrates of Fenton reaction (Fe(2+)+H(2)O(2)-->Fe(3+)+*OH+OH-) may be used to experimentally induce oxidative damage to macromolecules. The study aimed at evaluating effects of Fe(2+) and/or H(2)O(2) on lipid peroxidation in porcine ovary homogenates.

MATERIALS AND METHODS: Ovary homogenates were incubated in the presence of either H2O2 (100, 50, 25, 10, 5.0, 2.5, 1.0, 0.5, 0.25, 0.01, 0.001 mM) or FeSO(4) (Fe2+) (300, 150, 75, 30, 15, 7.5, 3.0, 1.5, 0.75 microM), or of those two factors used together: Fe(2+) (30 microM) plus H(2)O(2) (concentrations as above), or H(2)O(2) (0.5 mM) plus Fe(2+) (concentrations as above). The concentration of malondialdehyde+4-hydroxyalkenals constituted the lipid peroxidation index.

RESULTS: H(2)O(2) alone did not affect lipid peroxidation in porcine ovary homogenates at all, whereas Fe(2+) (300, 150, 75, 30, and 15 microM) alone increased lipid peroxidation in a concentration dependent manner. When Fe(2+) and H(2)O(2) were applied together, lipid peroxidation increased significantly without any concentration related effect of H(2)O(2), but with a clear concentration dependent effect of Fe(2+); the damaging effect of Fe(2+), used together with H(2)O(2), was the same as the one, obtained after Fe(2+) was applied alone.

CONCLUSIONS: In conclusion, external H(2)O(2) is not indispensable for experimental induction of lipid peroxidation by Fenton reaction in porcine ovary homogenates....

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Journal Article 2010; 31(3): 348-352 PubMed PMID: 20588238 Citation  Keywords:  Action Potentials:drug effects, Animals, Antioxidants:therapeutic use, Brain Ischemia:prevention & control, Female, Hippocampus:drug effects, In Vitro Techniques, Indoles:therapeutic use, Lactation, Pregnancy, Pregnancy Complications, Cardiovascular:drug .   

OBJECTIVE: Damage to the developing brain may be caused by maternal environment, nutritional deficiencies, failure of protective mechanisms, etc. Further, the developing brain may be damaged by intrauterine ischemia or by ischemia in newborns complicated by perinatal asphyxia. There is an effort to find agents with neuroprotective effect on the developing brain. The aim was to study the effect of the new pyridoindole antioxidant SMe1EC2 on the resistance of offspring hippocampus exposed to ischemia in vitro after treatment of mothers.

MATERIALS AND METHODS: The electrically evoked responses were determined by extracellular recording from offspring hippocampal slices. The effect of oral treatment of rats with SMe1EC2 over 18 consecutive days, from day 15 of gestation to day 10 post partum (PP) was analyzed in the model of ischemia in vitro measured on the hippocampus of 21-day-old pups, with focus on neuronal function recovery in reoxygenation.

RESULTS: Increased recovery of neuronal response was found at the end of 20-min reoxygenation in offspring hippocampal slices exposed to 10-min hypoxia/hypoglycemia from rats whose mothers were treated with the dose of 50 and 250 mg/kg of SMe1EC2, compared to control offspring slices (mothers received vehicle over the same time).

CONCLUSIONS: The increased offspring hippocampus resistance to hypoxia/hypoglycemia due to 18-day maternal treatment with SMe1EC2 might have been obtained via the transplacental way as well as in the neonatal period via breast milk, skin and saliva. The manifested neuroprotective effect of SMe1EC2 on the developing brain might find exploitation during risk pregnancy and delivery....

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Comparative Study 2010; 31(3): 363-369 PubMed PMID: 20588237 Citation  Keywords:  Animals, Antioxidants:pharmacology, Bromates:adverse effects, Dose-Response Relationship, Drug, In Vitro Techniques, Indoles:pharmacology, Kidney:drug effects, Lipid Peroxidation:drug effects, Liver:drug effects, Lung:drug effects, Melatonin:pharmacology,.   

OBJECTIVE: Potassium bromate (KBrO3) is a prooxidant and carcinogen. Melatonin is a highly effective antioxidant. Indole-3-propionic acid (IPA; indole substance) and propylothiouracil (PTU; antithyroid drug) reveal some antioxidative effects. The aim of the study was to evaluate KBrO3-induced lipid peroxidation (LPO) in vitro in tissues collected from control or melatonin-treated rats, and to compare potential preventive effects of melatonin, IPA and PTU.

MATERIALS AND METHODS: Kidney, liver and lung homogenates from either control or melatonin-pretreated rats (0.0645 mmol/kg b.w., i.p., twice daily, 10 days) were incubated in the presence of KBrO3 (0.1, 0.5, 1.0, 2.5, 5.0, 10.0 mM). Then, control lung homogenates were incubated with KBrO3 (10.0 mM) together with melatonin (0.01, 0.1, 0.5, 1.0, 5.0, 7.5 mM), or with IPA or with PTU. LPO products (malondialdehyde+4-hydroxyalkenals) were measured spectrophotometrically.

RESULTS: Melatonin injections prevented KBrO3-induced LPO in lung homogenates. Melatonin, IPA and PTU, used in vitro, reduced KBrO3-induced LPO in control lungs. Unexpectedly, KBrO3 caused a concentration-dependent decrease in LPO in liver and kidney homogenates from control but not from melatonin-treated rats.

CONCLUSIONS: Potassium bromate-induced LPO in the rat lung homogenates suggests that the lung may be the target for this carcinogen. An exposure of organisms to melatonin decreases tissue sensitivity to KBrO3-induced damage, possibly by restoring the oxidative balance....

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Journal Article 2008; 29(5): 790-793 PubMed PMID: 18987595 Citation  Keywords:  Adrenergic beta-Antagonists:pharmacology, Androstadienes:pharmacology, Calcimycin:pharmacology, Carbazoles:pharmacology, Humans, In Vitro Techniques, Male, N-Formylmethionine Leucyl-Phenylalanine:pharmacology, Neutrophils:drug effects, Oxidants:metabolism.   

OBJECTIVES: To compare three stimuli which activate human neutrophils with different signal transduction mechanisms, in order to better localize the effect of the beta-adrenoceptor antagonist carvedilol (CARV) on superoxide generation (O2*-) and myeloperoxidase release (MPO). The effect of CARV [0.1-100 micromol/l] on O2*- generation and MPO release from isolated human neutrophils was studied after specific receptor activator N-formyl-methionyl-leucyl-phenylalanine (fMLP) and nonreceptor phorbol-12-myristate-13-acetate (PMA) and calcium ionophor (A23187) stimuli.

METHODS: O2*- generation was measured as superoxide dismutase inhibitable reduction of cytochrome c and MPO release as the oxidation of o-dianisidine in the presence of hydrogen peroxide in a spectrophotometer Hewlet Packard 8452 A at respective 550 and 463 nm.

RESULTS: CARV had no effect on O2*- generation and MPO release in nonstimulated cells. In the concentration 10 and 100 micromol/l, it significantly decreased fMLP and PMA stimulated O2*- generation and MPO release. Incubation of neutrophils with CARV [100 micromol/l] caused significant inhibition of O2*- generation and MPO release induced by A23187. Wortmannin, a specific inhibitor of 1-phosphatidylinositol-3-kinase, inhibited significantly only fMLP stimulated O2*- generation. CARV [100 micromol/l] with wortmannin [50 nmol/l] further decreased O2*- generation after the same stimulus.

CONCLUSION: CARV decreased O2*- generation and MPO release from isolated human neutrophils both by membrane-operating stimulus - fMLP and membrane bypassing activators - PMA and A 23187. This fact, together with effect the of wortmannin, indicates that the inhibition may be attributed to the non-specific action of CARV and its interference with phospholipase D signaling pathway, which plays only a minor role in proteinkinase C stimulated O2*- generation....

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Journal Article 2007; 28(6): 854-860 PubMed PMID: 18063937 Citation  Keywords:  Animals, Antipsychotic Agents:pharmacology, Clozapine:pharmacology, Dose-Response Relationship, Drug, Glucose:pharmacology, In Vitro Techniques, Insulin:secretion, Islets of Langerhans:drug effects, Male, Rats, Rats, Wistar, Statistics, Nonparametric,.   

OBJECTIVES: Treatment with the atypical antipsychotic clozapine is frequently associated with metabolic side-effects such as weight gain, lipid abnormalities and diabetes mellitus. Since insulin is a hormone that is involved in both the regulation of body weight, as well as in lipid metabolism and glucose regulation, an effect of clozapine on insulin secretion and/or on insulin action - at least in part - might explain its capability to induce these side-effects. The aim of this study was therefore to examine the influence of clozapine on insulin release in vitro.

METHODS: The effect of clozapine in three different concentrations, 10(-6), 10(-5) and 10(-4) M, was investigated on both basal (i.e. 3.3 mM glucose) and glucose-stimulated (i.e. 16.7 mM glucose) insulin release, using isolated rat islets of Langerhans.

RESULTS: The presence of clozapine in the concentrations of 10(-6), 10(-5) and 10(4 )M significantly increased basal insulin release compared to the control after 4 h (but not after 1 h) of incubation. As regards the glucose-stimulated insulin release, the presence of clozapine in the concentrations of 10(-5) and 10(-4) M, but not in that of 10(-6) M, significantly inhibited the glucose-stimulated insulin release compared to the control after both 1 and 4 h of incubation.

CONCLUSION: This study demonstrates that the atypical antipsychotic clozapine exerts dual effects on insulin release in vitro, through stimulating basal insulin release and inhibiting glucose-stimulated insulin release. Both these effects of clozapine on insulin release may contribute to its disadvantage inducing metabolic side-effects....

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Journal Article 2006; 27(Suppl 2): 9-13 PubMed PMID: 17159769 Citation  Keywords:  Adolescent, Adult, Aged, Aniline Compounds:metabolism, Animals, Anisoles:pharmacokinetics, Carcinogens:pharmacokinetics, Child, Child, Preschool, Cytochrome P-450 Enzyme System:metabolism, Female, Humans, In Vitro Techniques, Male, Metabolic Detoxication,.   

OBJECTIVES: The detoxifying metabolism of a potent rodent carcinogen, 2-nitroanisole (2-NA) by human, rabbit and rat cytochromes P450 (P450) was investigated. Comparison between P450s of experimental animals and humans is essential for the extrapolation of animal carcinogenicity data to the human situation and to assess health risk.

METHODS: HPLC with UV detection was employed for the separation and characterization of 2-NA metabolites formed by hepatic microsomes, human recombinant P450s and purified rat and rabbit P450s.

RESULTS: An O-demethylated metabolite of 2-NA, 2-nitrophenol (2-NP), and two oxidation products of this metabolite [2,5-dihydroxynitrobenzene (2,5-DNB) and 2,6-dihydroxynitrobenzene (2,6-DNB)] were generated by microsomes and P450s from the species investigated, but at different levels. All the metabolites are detoxication products. 2-NP is the major metabolite generated by rabbit and rat microsomes, but 2,5-DNB is the predominant product in human microsomes. Using human recombinant P450s and purified rodent P450s, we found that human P450 2E1, 1A1 and 2B6 as well as orthologous animal P450s were the most efficient enzymes oxidizing 2-NA to 2-NP, while P450 2E1 and 1A1 were the most effective in the formation of 2,5-DNB and 2,6-DNB. In human hepatic microsomes, 2-NA was oxidized mainly by P4502E1. 2-NA and its reductive metabolite o-anisidine induced rat hepatic and renal P450 1A1/2 and NAD(P)H:quinone oxidoreductase (NQO1), thus modifying their own detoxication and/or activation pathways.

CONCLUSIONS: The data demonstrated the participation of orthologous P450s in 2-NA oxidation by all species and indicated that the rat and rabbit might serve as suitable models to mimic 2-NA oxidation in man....

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Journal Article 2006; 27(4): 483-486 PubMed PMID: 16892001 Citation  Keywords:  Acetates:pharmacology, Age Factors, Animals, Binding, Competitive, Cations:metabolism, Cells, Cultured, Copper:metabolism, Dose-Response Relationship, Drug, Female, Gonadotropin-Releasing Hormone:metabolism, In Vitro Techniques, Luteinizing Hormone:metabo.   

: The present studies were undertaken to examine the effect of copper and nickel salts and their complexes with GnRH on LH release from the pig anterior pituitary cells in vitro. The potency of Cu-GnRH and Ni-GnRH binding to GnRH receptors with iodinated GnRH as a radioactive tracer was also verified. The incubation of pig pituitary cells with Cu and Ni acetate salts showed no effect of the studied ions on LH release at any concentration used. However, nickel salt at a lower dose (10(-10) and 10(-9) M) tended to decrease LH output. By contrast, the native GnRH as well as its metal complexes significantly stimulated LH release after three hours of treatment and Cu-GnRH was found to be the most effective. The results showed that Cu and Ni complexes with GnRH but not their acetate salts are effective in LH release from pig pituitary cells collected from adult female pigs....

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