RESUMO
Many animals convert ß-carotene to retinol to meet their vitamin A (VA) requirement. However, this pathway is inefficient in many carnivores. This study quantified the plasma response to a single oral dose of [(2) H(8)]-ß-carotene in adult domestic cats, including measurement of [(2) H(4)]-retinol derived from the dose. Cats were fed with either a control diet containing adequate VA (n = 5) or a VA-devoid diet (n = 5) for 28 days. An oral dose of either 5 mg/kg body weight (BW) (n = 4) or 10 mg/kg BW (n = 6) of [(2) H(8) ]-ß-carotene was administered on day 28. Plasma samples were collected prior to dosing and at 6, 12, 24, 32, 48, 72, 120, 168 and 216 h post-dose. Plasma retinoids and ß-carotene were measured using HPLC and [(2) H(4)]-retinol by GC-ECNCI-MS (gas chromatography/electron capture negative chemical ionization/mass spectrometry). ß-carotene was undetectable in plasma prior to dosing. Post-dose, mean peak plasma ß-carotene was 0.37 ± 0.06 nmol/ml at 9.0 ± 1.8 h following the dose, while [(2) H(4) ]-retinol peaked at 3.71 ± 0.69 pmol/ml at 55.2 ± 16.3 h. The ratio per cent of total area under the curve for [(2) H(4)]-retinol compared with the ß-carotene response was 4.6 ± 2.6%. There was little effect of diet or dose on the ß-carotene or [(2) H(4)]-retinol responses. The appearance of [(2) H(4)]-retinol in plasma indicates that cats are capable of converting ß-carotene to active VA. Conversion efficiency was not calculated in this study, but it is likely inadequate to meet cats' VA requirement without the inclusion of preformed VA in the diet.
Assuntos
Gatos/metabolismo , Vitamina A/metabolismo , beta Caroteno/metabolismo , Administração Oral , Ração Animal/análise , Animais , Dieta/veterinária , Relação Dose-Resposta a Droga , Feminino , Organismos Livres de Patógenos Específicos , Vitamina A/administração & dosagem , beta Caroteno/administração & dosagemRESUMO
Epidemiological and toxicological studies often require the analysis of large numbers of samples for biological markers of exposure. The goal of this work was to develop a class-selective ELISA to detect groups of structurally closely related mercapturic acids with small nonpolar S-substituents. An assay was developed with strong recognition for mercapturates including S-benzylmercapturic acid (IC50 = 0.018 micromol/L), S-n-hexylmercapturic acid (IC50 = 0.021 micromol/L), S-phenylmercapturic acid (IC50 = 0.024 micromol/L), and S-cyclohexylmethylmercapturic acid (IC50 = 0.042 micromol/L). The same assay also showed weaker recognition for S-(1-hydroxynaphthal-2-yl)mercapturic acid and S-allylmercapturic acid (IC50 = 1.1 and 1.7 micromol/L, respectively). Subtle modifications to the hapten linker structure of the coating antigen proved to have a strong impact on the selectivity and the specificity of the assay. A slightly modified assay showed high recognition for S-benzylmercapturic acid (IC50 = 0.018 micromol/L) and weaker recognition for seven other mercapturic acids (IC50 = 0.021-10 micromol/L). Strong positive assay responses were detected in 12 urine samples obtained from persons with no known occupational exposure to exogenous electrophilic xenobiotics. Solid phase extraction and cross-reactivity indicated that the presumptive immunoreactive materials were similar in size and polarity to S-benzylmercapturic acid. The assay was more selective to mercapturic acids than the spectrophotometric thioether assay.
Assuntos
Acetilcisteína/urina , Exposição Ambiental/análise , Ensaio de Imunoadsorção Enzimática/métodos , Monitoramento Ambiental , Humanos , Resíduos de Praguicidas , Sensibilidade e EspecificidadeRESUMO
BACKGROUND AND PURPOSE: Soluble epoxide hydrolase inhibitors (sEHIs) possess anti-inflammatory, antiatherosclerotic, antihypertensive and analgesic properties. The pharmacokinetics (PK) and pharmacodynamics in terms of inhibitory potency of sEHIs were assessed in non-human primates (NHPs). Development of a sEHI for use in NHPs will facilitate investigations on the role of sEH in numerous chronic inflammatory conditions. EXPERIMENTAL APPROACH: PK parameters of 11 sEHIs in cynomolgus monkeys were determined after oral dosing with 0.3 mg·kg(-1). Their physical properties and inhibitory potency in hepatic cytosol of cynomolgus monkeys were examined. Dose-dependent effects of the two inhibitors 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU) and the related acetyl piperidine derivative, 1-trifluoromethoxyphenyl-3-(1-acetylpiperidin-4-yl) urea (TPAU), on natural blood eicosanoids, were determined. KEY RESULTS: Among the inhibitors tested, TPPU and two 4-(cyclohexyloxy) benzoic acid urea sEHIs displayed high plasma concentrations (>10 × IC(50)), when dosed orally at 0.3 mg·kg(-1). Although the 4-(cyclohexyloxy) benzoic acid ureas were more potent against monkey sEH than piperidyl ureas (TPAU and TPPU), the latter compounds showed higher plasma concentrations and more drug-like properties. The C(max) increased with dose from 0.3 to 3 mg·kg(-1) for TPPU and from 0.1 to 3 mg·kg(-1) for TPAU, although it was not linear over this range of doses. As an indication of target engagement, ratios of linoleate epoxides to diols increased with TPPU administration. CONCLUSION AND IMPLICATIONS: Our data indicate that TPPU is suitable for investigating sEH biology and the role of epoxide-containing lipids in modulating inflammatory diseases in NHPs.
Assuntos
Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/farmacocinética , Epóxido Hidrolases/antagonistas & inibidores , Analgésicos/farmacocinética , Analgésicos/farmacologia , Animais , Anti-Inflamatórios/farmacocinética , Anti-Inflamatórios/farmacologia , Anti-Hipertensivos/farmacocinética , Anti-Hipertensivos/farmacologia , Citosol/efeitos dos fármacos , Citosol/enzimologia , Citosol/metabolismo , Eicosanoides/metabolismo , Inibidores Enzimáticos/sangue , Epóxido Hidrolases/metabolismo , Feminino , Inflamação/enzimologia , Inflamação/metabolismo , Fígado/efeitos dos fármacos , Fígado/enzimologia , Fígado/metabolismo , Macaca fascicularis , Compostos de Fenilureia/farmacologia , Piperidinas/farmacologia , Ureia/análogos & derivados , Ureia/farmacocinética , Ureia/farmacologiaRESUMO
A series of 1,5-diphenyl-3-alkoxy (or acyloxy)-1H-1,2,4-triazoles were synthesized and assayed in the rat adjuvant induced arthritis model. Some compounds show significant anti-inflammatory activity.
Assuntos
Anti-Inflamatórios não Esteroides/síntese química , Derivados de Benzeno/síntese química , Triazóis/síntese química , Animais , Artrite Experimental/tratamento farmacológico , Derivados de Benzeno/farmacologia , Fenômenos Químicos , Química , Masculino , Ratos , Triazóis/farmacologiaRESUMO
Amidines obtained from benzamides and DMF- or DMA-dimethylacetal were cyclized with phenylhydrazines to 3H- or 3-methyltriazoles. 3-Ethyltriazoles were synthesized from diacylamides. Triazole-3-carboxylic acides were prepared starting from anilines. The compounds were assayed in the rat adjuvant induced arthritis model. Some compounds show significant anti-inflammatory activity.
Assuntos
Anti-Inflamatórios não Esteroides/síntese química , Triazóis/síntese química , Animais , Artrite Experimental/tratamento farmacológico , Fenômenos Químicos , Química , Masculino , Ratos , Triazóis/farmacologiaRESUMO
The venom of the South African scorpion Parabuthus transvaalicus was characterized using a combination of mass spectrometry and RP-HPLC separation and bioassays. The crude venom was initially separated into 10 fractions. A novel, moderately toxic but very high abundance peptide (birtoxin) of 58 amino-acid residues was isolated, identified and characterized. Each purification step was followed by bioassays and mass spectroscopy. First a C4 RP-HPLC column was used, then a C18 RP Microbore column purification resulted in > 95% purity in the case of birtoxin from a starting material of 230 microg of crude venom. About 12-14% of the D214 absorbance of the total venom as observed after the first chromatography step was composed of birtoxin. This peptide was lethal to mice at low microgram quantities and it induced serious symptoms including tremors, which lasted up to 24 h post injection, at submicrogram amounts. At least seven other fractions that showed different activities including one fraction with specificity against blowfly larvae were identified. Identification of potent components is an important step in designing and obtaining effective anti-venom. Antibodies raised against the critical toxic components have the potential to block the toxic effects and reduce the pain associated with the scorpion envenomation. The discovery of birtoxin, a bioactive long chain neurotoxin peptide with only three disulfide bridges, offers new insight into understanding the role of conserved disulfide bridges with respect to scorpion toxin structure and function.
Assuntos
Neurotoxinas/química , Neurotoxinas/isolamento & purificação , Venenos de Escorpião/química , Venenos de Escorpião/isolamento & purificação , Sequência de Aminoácidos , Animais , Cromatografia Líquida de Alta Pressão , Masculino , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular , Peptídeos/química , Peptídeos/isolamento & purificação , Conformação Proteica , Venenos de Escorpião/toxicidade , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , África do Sul , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
The two most venomous species of the family Buthidae, Leiurus quinquestriatus and Androctonus crassicauda, are found in Africa and in the Middle East. Potency and paraspecific activities of A. crassicauda antivenom (RSHC anti-Ac) were tested against L. quinquestriatus venom. The sera produced by Refik Saydam Hygiene Center (RSHC) showed strong reactivity against the venoms of A. crassicauda and L. quinquestriatus in western blotting and dot-blot analysis. RSHC anti-Ac presents immunoactivity and neutralizing potential against Leiurus quinquestriatus venom. Neutralization capacity of antivenom was found to be 400 µL against 40 minimum lethal doses (MLD) of A. crassicauda scorpion venom and 10 MLD of L. quinquestriatus venom. This study indicates that the RSHC anti-Ac could be used for treating L. quinquestriatus stings.(AU)