43 research outputs found
Comparison of hydrolytic and conjugative biotransformation pathways in horse, cattle, pig, broiler chick, rabbit and rat liver subcellullar fractions
No full textTo complete a studyaimed at investigating the pattern of the basal activities of liver xenobioticmetabolizing enzymes in major and minor species intended for meat production, microsomal carboxylesterases and some conjugating enzyme activities were determined and compared in liver preparations from horses, cattle, pigs, rabbits and broiler chicks, using the rat as a reference species. Horses and broiler chicks exhibited a lower microsomal carboxylesterase activity towards indophenyl or p-nitrophenyl acetate than that measured in cattle or pig subfractions. Among food-producing species, the rate of glucuronidation of either 1-naphthol or p-nitrophenol was in the order pigs approximately rabbits > horses >> cattle > broiler chicks. The widest variations were observed in the acetylation capacity towards p-aminobenzoic acid or isoniazid, which in rabbits was 3-fold to 11-fold greater than that displayed by any other examined species; low but measurable activities were found in equine and bovine cytosols. The activity of cytosolic glutathione S-transferase (GST) accepting the general substrate 1-chloro-2,4-dinitrobenzene was significantly higher in rabbits, horses and pigs than in rat, broiler chicks and cattle. Finally, an uneven pattern of activity towards the other tested GST substrates - 3,4-dichloronitrobenzene, ethacrinic acid or 1,2-epoxybutane - was observed, possibly reflecting the species-related expression of different GST classes; in this respect, the conjugative capacity displayed by horses was higher than or comparable to that found in the other food-producing specie
Effect of the illegal oral and intramuscolar administration of dexamethasone (DEX) upon liver CYP3A expression in veal calves.
No full textSerum antioxidant status and oxidative stress parameters as biomarkers for illicit treatments with growth promoting agents in veal calves
No full textIn vitro formation of metabolic-intermediate cytochrome P450 complexes in rabbit liver microsomes by tiamulin and various macrolides
No full textTiamulin and a number of macrolides were evaluated as to their ability in forming metabolic-intermediate (MI) complexes with cytochrome P450 in liver microsomes from rabbits bred for meat production. Complex formation, which occurred only in preparations where the expression of P450 3A was increased as the result of rifampicin pre-treatment and with different kinetics, was in the order tiamulin > erythromycin > TAO approximate to roxithromycin approximate to tylosin and did not take place with tilmicosin and spiramycin. Most of the tested compounds underwent an oxidative N-dealkylation and a good relationship could be found between the rate of N-dealkylase activity in induced preparations and the aptitude in generating MI complexes. Although the results from in vitro studies should be interpreted with caution, it is suggested that the potential for in vivo drug interactions also exists in the rabbit for tiamulin and for four out of the six tested macrolide
Inhibition of in vitro xenobiotic- and testosterone metabolism in liver microsomes from veal calves experimentally treated with a combination of 17ß-oestradiol, clenbuterol and dexamethasone.
No full textIs fasting glucose variability a risk factor for retinopathy in people with type 2 diabetes?
No full textAIMS: Fasting plasma glucose variability strongly predicts the incidence of cardiovascular events in type 2 diabetic patients. We prospectively assessed whether fasting plasma glucose variability predicts the development/progression of retinopathy in a large cohort of type 2 diabetic outpatients. METHODS: In the period 1996-1999, 1019 type 2 diabetic participants (aged 69+/-11 years) in the Verona Diabetes Study underwent at least 3 fasting plasma glucose (FPG) determinations and an eye examination by retinography. Of these, 746 underwent a 2nd eye examination in the period 2000-2004, while 273 did not (102 patients had died before undergoing the 2nd eye examination). For each patient, the mean (M-FPG) and the coefficient of variation of FPG (CV-FPG) were computed. RESULTS: By the 2nd eye examination, 124 patients had either developed new retinopathy (79 patients) or progressed to a more severe degree of retinopathy (45 patients). In a multivariable logistic regression analysis, the development/progression of retinopathy was independently predicted by average glycaemia over time, expressed as glycated haemoglobin (odds ratio [OR] 1.82, 95%CI 1.40-2.38 for 1 SD increase) or M-FPG (OR 1.88, 1.47-2.41), but not by CV-FPG. Among other independent variables, HDL-cholesterol was inversely associated with the development/progression of retinopathy. CONCLUSIONS: These results suggest that in elderly type 2 diabetic patients the magnitude of hyperglycaemia, but not fasting plasma glucose variability, strongly predicts the development/progression of diabetic retinopathy independently of other known risk factors
Characterization of hepatic subfractions from phenobarbital induced cattle and their use in the study of the metabolic fate of boldenone and androsta-1,4-diene-3,17-dione
No full textDespite the EU ban (1), anabolic steroids such as boldenone (Bol) are currently illicitly used as growth promoters for cattle fattening. Monitoring of the ban requires further knowledge about biotransformation processes to identify a possible biomarker of illegal treatment. In this study hepatic subfractions from phenobarbital (PB)-induced or untreated cattle were first characterized as to their cytochrome P450 (CYP) expression and then used to investigate the metabolic pathways of Bol and its important metabolite/precursor androsta-1,4-diene-3,17-dione (ADD).Results: As expected, the main isoforms involved in PB induction were CYP2B, CYP2C and CYP3A, showing 1.5 to 15 fold increase in enzyme activity and 2 to 3 fold increase in protein levels. Incubations with 17β-Bol revealed ADD as the major biotransformation product in both C and PB subfractions. Moreover, three hydroxylated metabolites (OH-Bol) were identified and the amount of one of them was 4 times higher in PB than in C group. Incubations with ADD yielded 17α- and 17β-Bol: both in C and PB fractions the β epimer was present to a far greater extent than the α epimer (about 20 fold). Also in this case the amount of one of the 3 OH-Bol formed was about 6 times higher in PB than in C group.
Conclusions: Only the enzymes responsible for OH-Bol generation would appear to be induced by PB; moreover this study demonstrate for the first time the in vitro production of 17α-Bol as the result of ADD incubation
Effect of breed upon cytochrome P450s and phase II enzymes expression in cattle liver
No full textCattle represent an important source of animal-derived food-products; nonetheless, our knowledge about the expression of drug-metabolizing enzymes (DMEs) in present and other food-producing animals still remains superficial, despite the obvious toxicological consequences. Breed represents an internal factor that modulates DME expression and catalytic activity. In the present work, the effect of breed upon relevant phase I and phase II DMEs was investigated at the pretranscriptional and post-translational levels in male Charolais (CH), Piedmontese (PM) and Blonde d'Aquitaine (BA) cattle. Because specific substrates for cattle have not yet been identified, the breed effect upon specific cytochrome P450 (P450), UDP-glucuronosyltransferase (UGT), or glutathione S-transferase (GST) DMEs, in terms of catalytic activity, was determined by using human marker substrates. Among P450s, benzphetamine N-demethylase, 16beta-, 6beta-, and 2beta-testosterone hydroxylase, aniline and p-nitrophenol hydroxylase, and alpha-naphthol and p-nitrophenol UGT activities were significantly higher in CH; in contrast, lower levels of CYP1A1-, CYP1A2-, CYP2B6-, CYP2C9-, CYP2C18-, CYP3A4-, and UGT1A1-like mRNAs were noticed, with CH < PM < or = BA as a trend. CYP2B and CYP3A mRNA results were confirmed with immunoblotting, too. As regards conjugative DMEs, UGT1A6-like mRNA levels were consistent with respective catalytic activities. Both 1-chloro-2,4-dinitrobenzene and 3,4-dichloronitrobenzene GST activities were higher in BA, and these results agreed with GSTA1-, GSTM1-, and GSTP1-like mRNA amounts. Correlation analysis between catalytic activities and mRNAs showed either significant or uneven results, depending on the substrate. These findings confirm previous data obtained in laboratory species; however, further studies are required to ascribe this behavior to pretranscriptional or post-translational phenomena
FIGURE 14 in A morphological and molecular study of Psilops, a replacement name for the Brazilian microteiid lizard genus Psilophthalmus Rodrigues 1991 (Squamata, Gymnophthalmidae), with the description of two new species
No full textFIGURE 14. The appendicular skeleton of Psilops paeminosus (MZUSP 79584). Pectoral (A) and pelvic (B) girdles, in ventral view. Carpal region in ventral (C) and dorsal (D) views. Tarsal region in ventral (E) and dorsal (F) views, respectively. Abbreviations: ac, astragalus-calcaneus; acf, anterior coracoid foramen; ce, centrale; cf, coracoid foramen; cl, clavicle; dc, distal carpal; dt, distal tarsal; epc, epicoracoid; fe, femur; fi, fibula; h, humerus; icl, interclavicle; il, ileum; is, isquium; pa, palmar; pb, pubis; pcf, posterior coracoid foramen; psi, pisiform; ra, radiale; s, sternum; sc, scapulocoracoid; se, suprascapula; ti, tibia; ul, ulnare. Scale bars for A and B = 1mm; scale bars for C-F = 0.25mm.Published as part of Rodrigues, Miguel Trefaut, Recoder, Renato, Jr, Mauro Teixeira, Roscito, Juliana Gusson, Guerrero, Agustín Camacho, Sales Nunes, Pedro M., Freitas, Marco Antonio De, Fernandes, Daniel Silva, Bocchiglieri, Adriana, Vechio, Francisco Dal, Leite, Felipe Sá Fortes & Nogueira, Cristiano De Campos, 2017, A morphological and molecular study of Psilops, a replacement name for the Brazilian microteiid lizard genus Psilophthalmus Rodrigues 1991 (Squamata, Gymnophthalmidae), with the description of two new species, pp. 451-482 in Zootaxa 4286 (4) on page 474, DOI: 10.11646/zootaxa.4286.4.1, http://zenodo.org/record/82866
A incorporação de bromélias epífitas no processo de restauração de áreas degradadas na mata atlântica: um estudo em Registro, SP.
No full textTradicionalmente os modelos de recuperação ambiental têm sido baseados em técnicas que contemplam apenas o componente arbóreo da vegetação, desconsiderando outras formas de vida responsáveis por boa parte da riqueza e complexidade estrutural de uma comunidade tropical. As bromélias têm indiscutível importância na dinâmica das formações vegetais sob domínio atlântico, destacando sua capacidade em criar microhabitats e ofertar recursos alimentares para animais, entre os quais, polinizadores e dispersores. Este trabalho teve como objetivo propor ações e subsidiar a incorporação de bromélias epífitas no processo de restauração ecológica, baseado nos dados referentes à sua distribuição horizontal e vertical na vegetação do entorno do Aeroporto de Registro (SP). As populações presentes nas árvores em uma área de 800m² foram quantificadas, identificadas e hierarquizadas quanto à sua aptidão para introdução no processo de restauração, de acordo com os seguintes parâmetros: i) Valor de Importância Epifítica (VIE), calculado a partir da soma das freqüências e densidades relativas, ii) preferência por luz, iii) presença em florestas secundárias e iv) resistência a danos. Aechmea nudicaulis, A. organensis, Tillandsia stricta, foram populações que apresentaram maior aptidão para introdução no processo de restauração da área. A proposta contempla a colocação de poleiros com estas espécies de bromélias ao longo da área em processo de restauração, como estratégia para aumentar a probabilidade da presença de animais polinizadores e dispersores. Quanto às árvores-suporte, constatou-se que há entre as espécies importantes na estrutura arbórea, algumas mais favoráveis ao estabelecimento de epífitas, como Andira fraxinifolia, Coussapoua microcarpa, Nectandra oppositifolia, Calophyllum brasiliense, Tapirira guianensis. Estas espécies devem ser priorizadas na restauração, uma vez que podem ser futuramente colonizadas por propágulos de bromélias, presentes em abundância na vegetação adjacente
