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1.
Chemosphere ; 194: 644-649, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29241139

RESUMEN

Seafood is associated with many beneficial effects on human health. However, the overall level of contaminants in biota has increased over the last two centuries and seafood is one of the source of oral exposition to contaminants. Therefore, this work aimed to evaluate cadmium, lead, mercury, arsenic, chromium and nickel presence in mussels and clams, from the Italian market, and the associated risk. The samples were from five different FAO areas. Analyses were carried out using inductively-coupled plasms-mass spectrometry. The sample concentrations were below the maximum levels stated by Commission Regulation (EC) 1881/2006, except one mussel sample, which was non-compliant for cadmium (2.13 ± 0.20 mg kg-1). For arsenic, nickel and chromium, maximum levels are not stated by the European Union. In this study, arsenic ranged from 1.29 to 13.35 mg kg-1 and nickel ranged from 1, and BMDL10 for lung bladder and skin cancer in all mussel samples was overcome, in the 100% and 25% of mussel and clam samples, respectively.


Asunto(s)
Arsénico/toxicidad , Bivalvos/química , Exposición a Riesgos Ambientales/análisis , Metales/análisis , Alimentos Marinos/análisis , Animales , Arsénico/análisis , Humanos , Italia , Espectrometría de Masas , Medición de Riesgo
2.
J Anim Physiol Anim Nutr (Berl) ; 101(5): 893-903, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27080058

RESUMEN

The Chianina, one of the oldest and most important cattle breeds of Italy, is now reared all over the world. The Chianina has been known and appreciated since ancient times because, from a nutritional point of view, its meat has no proper rivals. To date, studies have been performed to evaluate the genetic profile of the breed, but knowledge about the chemical profile is generally lacking. Due to the increased interest from farmers regarding breeding of the Chianina, this study proposes a preliminary evaluation of main endogenous urinary corticosteroids (cortisol and cortisone) and most commonly used synthetic one (dexamethasone). Moreover, after recent findings regarding the presence of endogenous prednisolone in the urine of more popular breeds, particular attention was given to analysis of the presence of prednisolone and prednisone, as well. For this aim, the urine samples of 12 young cows and 30 young bulls was collected at the farms and analysed using a fit-for-purpose LC-MS/MS method. The preliminary results of this study show that prednisolone was found only in Chianina females (3 out of 12). Cortisol and cortisone were found at concentrations that showed a high inter-individual variability, and that were higher in female urine compared to that of males.


Asunto(s)
Bovinos/fisiología , Cortisona/orina , Hidrocortisona/orina , Prednisolona/orina , Animales , Bovinos/genética , Bovinos/orina , Cromatografía Liquida , Cortisona/química , Femenino , Hidrocortisona/química , Masculino , Estructura Molecular , Prednisolona/química , Espectrometría de Masas en Tándem
3.
Drug Test Anal ; 9(4): 561-570, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27448217

RESUMEN

Under European legislation, the use of growth promoters is forbidden in food-producing livestock. The application of unofficial protocols with diverse combinations of veterinary drugs, administered in very low concentrations, hinders reliable detection and subsequent operative prevention. It was observed that nandrolone (anabolic steroid) and ractopamine (ß-adrenergic agonist) are occasionally administered to animals, but little is known about their synergic action when they are administered together. Two specific analytical methods based on liquid chromatography-tandem mass spectrometry have been developed, both of which include hydrolysis of the corresponding conjugates. For the nandrolone method, solid-phase extraction was necessary for the complete elimination of the interferences, while employment of the Quantitation Enhanced Data-Dependent scan mode during MS acquisition of ractopamine enabled the utilization of simple liquid-liquid extraction. The nandrolone method was linear in the range of 0.5-25 ng/mL, while the ractopamine calibration curve was constructed from 0.5 to 1000 ng/mL. The corresponding coefficients of correlations were >0.9907. The lower limit of quantification for both methods was 0.5 ng/mL, followed by overall recoveries >81%. Precisions expressed as relative standard deviations were <17%, while matrix effects were minimal. Urine samples taken at the slaughterhouse from veal calves enrolled in an experimental treatment consisting of intramuscular administration of ß-nandrolone-phenylpropionate accompanied with a ractopamine-enriched diet were analysed. Those methods might be useful for studying the elimination patterns of the administered compounds along with characterization of the main metabolic pathways. Copyright © 2016 John Wiley & Sons, Ltd.


Asunto(s)
Anabolizantes/orina , Bovinos/orina , Sustancias de Crecimiento/orina , Nandrolona/orina , Fenetilaminas/orina , Espectrometría de Masas en Tándem/métodos , Animales , Cromatografía Líquida de Alta Presión/métodos , Inocuidad de los Alimentos , Límite de Detección , Masculino , Detección de Abuso de Sustancias/métodos
4.
Food Chem ; 212: 296-304, 2016 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-27374536

RESUMEN

This study analysed the usefulness of near infrared spectroscopy (NIRS), combined with volatile compound (VOC) and fatty acid (FA) analyses, for the authentication of the unique Italian Valle d'Aosta Arnad Protected Designation of Origin (PDO) lard. Ensuring the authenticity of high value meat products remains an emerging topic within the food sector. This study validated a FA, VOC and NIRS model for use in the authentication of Arnad PDO lard. The model showed a high potential rate to recognize patterns in lard samples. In particular the sensitivity and specificity calibration values were both 100%, and cross-validation models were performed using FAs and VOCs separately. The NIRS model obtained sensitivity and specificity values of 98.2% in the calibration data set, and 94.4% in the cross-validation step. This analytical approach may represent an effective tool to prevent food fraud, which is crucial for meat derived products with a high commercial value.


Asunto(s)
Grasas de la Dieta/análisis , Ácidos Grasos/análisis , Productos de la Carne/análisis , Espectroscopía Infrarroja Corta/métodos , Italia , Sensibilidad y Especificidad , Volatilización
5.
Chemosphere ; 154: 482-490, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27085062

RESUMEN

Bee products, such as honey, are widely consumed as food and consumer interest is currently oriented towards organic foods. Regarding this, the European Commission establishes that the qualification of organic honey and other beekeeping products as being from organic production is closely bound with the characteristics of hive treatments as well as the quality of the environment. Agricultural contamination with pesticides is a challenging problem that needs to be fully addressed, in particular in the field of organic production systems. In this study, the occurrence of different classes of contaminants selected as representative of potential contamination sources were investigated in 59 organic honeys: organochlorines, OCs; organophosphates, OPs; polychlorobiphenyls, PCBs and polybromodiphenylethers, PBDEs. A method based on Accelerated Solvent Extraction with "in line" clean-up and GC-MS/MS detection was developed to detect contaminants. Residues of many pesticides were found in most of the samples investigated. The majority of honey samples contained at least one of the pesticides, even if their concentrations were found to be lower than its MRL. Diazinon, Mevinphos, Coumaphos, Chlorpyrifos and Quinoxyfen were the residues frequently detected in samples coming from the apple and citrus orchard areas. Furthermore, the results of the present study show that the presence of the residue in organic honey may also be affected by the geographical area (e.g. the presence of an agricultural system) confirming honey bee and beehive matrices as appropriate sentinels for monitoring contamination in the environment. The optimised method proved to be simple and rapid, requiring small sample sizes and minimising solvent consumption, due to the ASE having an "in line" clean-up step.


Asunto(s)
Abejas , Contaminantes Ambientales/análisis , Contaminación de Alimentos , Miel/análisis , Plaguicidas/análisis , Compuestos Orgánicos Volátiles/análisis , Agricultura , Animales , Monitoreo del Ambiente/métodos , Italia , Espectrometría de Masas en Tándem/métodos
6.
Chemosphere ; 153: 162-9, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27016811

RESUMEN

Residues of environmental contaminants in food represent a concern in food safety programs. In this study, the distribution of persistent organic pollutants (POPs) were evaluated in 79 tuna samples from FAO areas 51 (Indian Ocean), 71 (Pacific Ocean), 34 (Atlantic Ocean), and 37 (Mediterranean Sea). 6 polychlorinated biphenyls (PCBs), 16 organochlorines (OCs) and 7 polybrominated biphenyl ethers (PBDEs) were selected as representative compounds according to EFSA POPs monitoring guidelines. An analytical method, based on Accelerated Solvent Extraction (ASE), with an "in-line" clean-up step and GC-MS/MS detection, was developed, validated and applied. PCBs were detected in all FAO areas, with a prevalence of 100% for most of them. In the FAO area 37, only, all PBDEs were detected. Only 5 OCs were detected. The results showed that POPs contamination of tuna reflects FAO area contamination; in particular FAO area 37 was the most polluted. Moreover, tuna muscle was an appropriate matrix for monitoring contamination and for obtaining information about food safety.


Asunto(s)
Éteres Difenilos Halogenados/metabolismo , Hidrocarburos Clorados/metabolismo , Atún/metabolismo , Contaminantes Químicos del Agua/metabolismo , Animales , Monitoreo del Ambiente , Cromatografía de Gases y Espectrometría de Masas , Océanos y Mares , Bifenilos Policlorados/metabolismo , Espectrometría de Masas en Tándem
7.
Artículo en Inglés | MEDLINE | ID: mdl-25768050

RESUMEN

The debate about the origin of prednisolone in animal organisms has lasted for 5 years. Bovine species have been the most studied, but studies on humans and horses are also present in the literature. Even if prednisolone in pigs does not yet represent a problem for control agencies, interest has recently increased with regard to this species. To date, there has been just a single study in the literature about this topic, performed on 10 sows treated with prednisolone or a synthetic analogue of adrenocorticotropic hormone. We therefore initiated a study on 80 pigs, a number considered representative in relation to the expected frequency (prevalence) of prednisolone detection in urine collected at slaughter. Prednisolone was detected in urine both at the farm and at the slaughterhouse, with a concentration and frequency higher at slaughter. The presence of prednisolone was also studied in the adrenal glands, where the corticosteroids are produced in response to stress, and it was detected in 89% of the samples. These results, together with the similar behaviours of prednisolone and cortisol, i.e. a mutual rise in the two corticosteroids in urine collected at the slaughterhouse and the correlation between the concentrations of the two corticosteroids in the adrenal glands, seem to indicate an endogenous origin of prednisolone in pigs.


Asunto(s)
Glándulas Suprarrenales/química , Glucocorticoides/orina , Hidrocortisona/orina , Prednisolona/orina , Mataderos , Animales , Femenino , Cromatografía de Gases y Espectrometría de Masas , Porcinos
8.
Anal Chim Acta ; 852: 137-45, 2014 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-25441890

RESUMEN

The presence of ß-boldenone II phase metabolites and prednisolone in urine samples, owing to endogenous or natural origin or illicit treatment, is under debate within the European Union. The detection of ß-boldenone conjugates, α-boldenone conjugates at concentrations higher than 2 ng mL(-1) and prednisolone above the cut-off level of 5 ng mL(-1) in urine have been, until now, critical in deciding if illegal drug use has occurred. The use of urine sometimes is not entirely satisfactory, especially when the drug is administrated at low doses or when its metabolic conversion is very fast. This subsequently would hamper its detection in urine. The introduction of a new, advantageous matrix where the illicit treatment can be investigated would be highly appreciated. In this study, we have developed and validated a simple and unique immunoaffinity clean-up procedure, which was applied to bovine bile samples, followed by two different analytical liquid chromatography-electrospray-tandem mass spectrometry methods. The first method tests androstadienedione, α- and ß-boldenone sulphate, glucuronate and related free forms, while the other method assays prednisolone, prednisone, dexamethasone, cortisone, and cortisol. The methods were validated according to European Commission Decision 2002/657/EC. The evaluated parameters were linearity, specificity, precision (repeatability and intra-laboratory reproducibility), recovery, decision limit and detection capability. The decision limits (CCα) were between 0.38 and 0.45 ng mL(-1) for anabolic steroids, and 0.13 and 0.15 ng mL(-1) as far as corticosteroids were concerned. Intra- and inter-day repeatability was below 15.8 and 19.9% for all analytes, respectively. The methods were applied to the analysis of some bile samples collected from untreated young bulls in order to investigate the presence of the studied steroids in this matrix.


Asunto(s)
Corticoesteroides/análisis , Androstadienos/análisis , Bilis/química , Bovinos , Espectrometría de Masas en Tándem/métodos , Testosterona/análogos & derivados , Animales , Bovinos/metabolismo , Cromatografía Líquida de Alta Presión/métodos , Glucurónidos/análisis , Técnicas de Inmunoadsorción , Límite de Detección , Masculino , Testosterona/análisis
9.
Animal ; 6(6): 1023-9, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22558973

RESUMEN

The rise in the frequency of detecting prednisolone in bovine urine from northern Italy has come into focus of attention in recent years. The possibility that neo-formation of prednisolone or that prednisone may occur in urine after collection of samples was therefore investigated. Cow urine collected for official routine controls in Lombardy containing more than 80 ng/ml cortisol, and prednisolone and prednisone below the decision limit (CCα) of the method (0.4 and 0.5 ng/ml, respectively) was used. The C1-2 dehydrogenation of naturally present cortisol and cortisone was checked by incubating urine, both contaminated and uncontaminated with faeces, at 37°C and by collecting samples at 0, 1, 2, 4, 6 and 24 h. The influence of Helix pomatia juice was also investigated in order to determine whether deconjugation could influence the reliability of the results. All samples were analysed by HPLC-MS3 for the presence of cortisol, cortisone, prednisolone and prednisone in negative electrospray ionisation mode, utilising the consecutive reaction monitoring of product ions derived from the formate molecular adduct ([M+HCOO]-). The observed neo-formation of prednisolone shows that inappropriate temperatures in sample storage and processing can result in an incorrect accusation of non-compliance. The faecal contamination of urine, performed with the aim to mimic a collection conducted without the necessary care, moreover, evoked a high increase in prednisolone concentration in two out of seven animals. Moreover, H. pomatia juice had no significant effect on the prednisolone concentration, indicating that this corticosteroid is present in its free form in cow urine.


Asunto(s)
Bovinos/orina , Cromatografía Líquida de Alta Presión/métodos , Prednisolona/orina , Espectrometría de Masa por Ionización de Electrospray/métodos , Orina/química , Animales , Bovinos/metabolismo , Cromatografía Líquida de Alta Presión/veterinaria , Cortisona/metabolismo , Cortisona/orina , Heces/química , Femenino , Glucuronidasa/metabolismo , Glucuronidasa/orina , Caracoles Helix/química , Hidrocortisona/metabolismo , Hidrocortisona/orina , Italia , Prednisolona/metabolismo , Prednisona/metabolismo , Prednisona/orina , Espectrometría de Masa por Ionización de Electrospray/veterinaria , Estadísticas no Paramétricas
10.
Steroids ; 76(1-2): 104-10, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20869978

RESUMEN

After a two-year period of the frequent detection of prednisolone-positive bovine urine samples in the Italian region of Lombardy, studies were initiated to investigate the source. Because the majority of positive samples were detected at the slaughterhouse, researchers hypothesised that, together with increased cortisol and cortisone, a small quantity of prednisolone could be produced by the cows in stressful situations. In the present study, three dairy cows underwent intramuscular treatments with tetracosactide hexaacetate, a synthetic analogue of adrenocorticotropic hormone, to simulate stress. The animals were slaughtered at the end of the study. The results indicated that prednisolone could be detected occasionally in the non-stressful state, but was consistently found in the urine of stressed cows (concentrations ranged from 1.01 to 4.08 ng/mL). To confirm the stress condition, urinary cortisol and cortisone were also detected at high concentrations in the urine, typically at concentrations of hundreds of nanograms per millilitre. The results of this preliminary study did not reveal the metabolic pathway responsible for prednisolone but suggested that this corticosteroid could be produced endogenously.


Asunto(s)
Prednisolona/orina , Animales , Bovinos , Cortisona/orina , Cosintropina/administración & dosificación , Cosintropina/análogos & derivados , Hidrocortisona/orina , Inyecciones Intramusculares , Estructura Molecular , Estereoisomerismo
11.
Minerva Cardioangiol ; 58(4): 441-8, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20938411

RESUMEN

AIM: NYHA classification divides into four classes. Although subjective and lacking of standardization, NYHA class II is in clinical practice often further subgrouped in IIA and IIB, where IIA class can be defined as dyspnea after running or climbing ≥ 2 ramps of stairs, and IIB class as dyspnea after fast walking or climbing 2 ramps of stairs. Validation of NYHA IIA and IIB sub-grouping was performed with left ventricular dysfunction questionnaire (LVD-36) results and echocardiographic left ventricular ejection fraction. METHODS: The study includes a total of 127 patients with both systolic and diastolic heart failure (mean age 65 ± 17, range 38-85 years). Sixteen patients were in NYHA class I, 81 patients in NYHA class II (45 in class IIA and 36 in class IIB) and 30 in class III. RESULTS: In class IIA patients' mean age was 64 ± 9 years, LVD-36 score 31.79 ± 14.06, EF 43 ± 10% (P = ns, P<0.001 and P=ns, respectively, vs. class I patients). In class IIB patients' mean age was 67 ± 10 years, LVD-36 score 48.90 ± 15.51, EF 39 ± 12% (P = ns, P < 0.0001 and P = ns, respectively, vs. IIA patients). In class III patients' mean age was 65 ± 11 years, LVD-36 score 65.17 ± 16.35, EF 32.77 ± 12.91% (P = ns, P < 0.01 and P = ns, respectively, compared with class IIB). CONCLUSION: NYHA class II sub-grouping appears an accurate method of classification and could represent a further useful tool in monitoring functional capacity of heart failure patients. NYHA class II sub-grouping correlates well with patients functional impairment and can therefore be implemented as an accurate method to better characterize heart failure patients.


Asunto(s)
Volumen Sistólico/fisiología , Disfunción Ventricular Izquierda/clasificación , Disfunción Ventricular Izquierda/fisiopatología , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Femenino , Insuficiencia Cardíaca/etiología , Humanos , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios , Terminología como Asunto , Ultrasonografía , Disfunción Ventricular Izquierda/diagnóstico por imagen
12.
Rapid Commun Mass Spectrom ; 23(1): 65-76, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19051232

RESUMEN

Proper storage conditions of biological samples are fundamental to avoid microbiological contamination that can cause chemical modifications of the target analytes. A simple liquid chromatography/tandem mass spectrometry (LC/MS/MS) method through direct injection of diluted samples, without prior extraction, was used to evaluate the stability of phase II metabolites of boldenone and testosterone (glucuronides and sulphates) in intentionally poorly stored equine urine samples. We also considered the stability of some deuterated conjugated steroids generally used as internal standards, such as deuterated testosterone and epitestosterone glucuronides, and deuterated boldenone and testosterone sulphates. The urines were kept for 1 day at room temperature, to mimic poor storage conditions, then spiked with the above steroids and kept at different temperatures (-18 degrees C, 4 degrees C, room temperature). It has been possible to confirm the instability of glucuronide compounds when added to poorly stored equine urine samples. In particular, both 17beta- and 17alpha-glucuronide steroids were exposed to hydrolysis leading to non-conjugated steroids. Only 17beta-hydroxy steroids were exposed to oxidation to their keto derivatives whereas the 17alpha-hydroxy steroids were highly stable. The sulphate compounds were completely stable. The deuterated compounds underwent the same behaviour as the unlabelled compounds. The transformations were observed in urine samples kept at room temperature and at a temperature of 4 degrees C (at a slower rate). No modifications were observed in frozen urine samples. In the light of the latter results, the immediate freezing at -18 degrees C of the collected samples and their instant analysis after thawing is the proposed procedure for preventing the transformations that occur in urine, usually due to microbiological contamination.


Asunto(s)
Cromatografía Liquida/métodos , Espectrometría de Masas en Tándem/métodos , Testosterona/análogos & derivados , Testosterona/orina , Animales , Congelación , Caballos , Estándares de Referencia , Reproducibilidad de los Resultados , Esteroides/metabolismo , Esteroides/orina , Temperatura , Testosterona/metabolismo , Factores de Tiempo
14.
Food Addit Contam ; 23(2): 126-32, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16449054

RESUMEN

Conflicting findings regarding the boldenone content of bovine faeces suggest it may be synthesized de novo in emitted faeces. We tested this hypothesis by analysing uncontaminated urine, fresh and various forms of dried faeces from 10 calves (not given boldenone) by liquid chromatography/tandem mass spectrometry for 17alpha- and 17beta-boldenone (alpha and beta BOL); 1,4-androstadiene-3,17-dione (ADD); 4-androstene-3,17-dione (AED), testosterone (T) and epitestosterone (ET). Urine contained no alpha BOL, beta BOL or ADD. The analysed substances were variably present in the rectal faeces, and at generally higher levels in faeces scraped from skin or stall floor. In pooled rectal faeces naturally dried for 13 days, alpha BOL, ADD, AED and ET levels were extremely high (much higher than accounted for by increases due to drying), and beta BOL and T were absent. It is concluded that de novo synthesis of alpha BOL and metabolites occurs naturally in bovine faeces and only uncontaminated urine should be analysed for illegal boldenone.


Asunto(s)
Heces/química , Testosterona/análogos & derivados , Anabolizantes/análisis , Anabolizantes/orina , Andrógenos/análisis , Andrógenos/orina , Androstadienos/análisis , Androstadienos/orina , Androstenodiona/análisis , Androstenodiona/orina , Animales , Bovinos , Epitestosterona/análisis , Epitestosterona/orina , Cromatografía de Gases y Espectrometría de Masas/métodos , Recto , Testosterona/análisis , Testosterona/orina
15.
Vet Res Commun ; 29(6): 507-15, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16215841

RESUMEN

A recent approach to the problem of contamination of agricultural products by aflatoxin B(1) (AFB(1)) is to add non-nutritional adsorbents to animal diets in order to sequester ingested aflatoxins. We conducted in vitro experiments to develop a rapid and cheap model using ruminal fluid to assess the ability of sorbent materials to bind AFB(1). Seven sorbents (hydrated sodium calcium aluminosilicate; clinoptilolite; zeolite; two types of bentonite; sepiolite; and PHIL 75), commonly added to bovine diets were incubated in water and ruminal fluid in the presence of AFB(1). Hydrated sodium calcium aluminosilicate, sepiolite and one of the bentonites bound 100% of the AFB(1) in the presence of both ruminal fluid and water; clinoptilolite bound about 80% of AFB(1) in both liquids; whereas the affinities for the mycotoxin of zeolite (50%) and the other sample of bentonite (60%) in water seem to be increased by about 40% in ruminal fluid incubations. PHIL 75 had the poorest binding ability: about 30% in water and 45% in ruminal fluid. In view of the differences in toxin binding in water and ruminal fluid, it is preferable to use the ruminal fluid model for the in vitro pre-screening of sorbent materials potentially useful as adjuvants to ruminant feeds.


Asunto(s)
Aflatoxina B1/química , Líquidos Corporales/química , Bovinos , Rumen/química , Adsorción , Aflatoxina B1/farmacocinética , Animales , Bentonita/química , Silicatos de Magnesio/química , Zeolitas/química
16.
Vet Res Commun ; 29 Suppl 2: 113-6, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16244935

RESUMEN

The risk related to the presence of residues in food of animal origin has to be carefully evaluated and it is important to distinguish between the residues of veterinary drugs and environmental contaminants. The first are easily monitored and only difficulty and occasionally exceed MRL concentrations, whereas the second ones can have prolonged and high level exposures. The Safety Margins of environmental contaminants are thus lower, and the risk increases for high level consumers. It is therefore important to ovoid transfer of pollutants to food of animal origin, especially when local contamination occur.


Asunto(s)
Contaminación de Alimentos/análisis , Xenobióticos/análisis , Animales , Bovinos , Huevos/análisis , Humanos , Carne/análisis , Leche/química , Aves de Corral , Porcinos , Xenobióticos/envenenamiento , Xenobióticos/toxicidad
18.
Food Addit Contam ; 21(8): 756-62, 2004 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15370825

RESUMEN

European Directive 96/22/EC, which controls veterinary residues in animals, does not permit the presence of synthetic growth promoters in products of animal origin or in livestock. Boldenone is categorized in class A3 (growth promoters -- steroids) and is thus a banned substance. Testing of veal urine for banned substances is part of the European Union statutory programme for animals going into the food chain. In relation to this monitoring, three studies were conducted to investigate the apparent presence of the banned growth promoter boldenone in veal urine, which was suspected as being caused by interference from faecal contamination of the sample. In the first study, urine samples were collected at different times (time 0 and after 30 min) using (1) a conventional zoonotechnical apron and (2) a technique designed specifically to avoid faecal contamination ('kettle'). This resulted in samples that were, respectively, positive and negative for the presence of alpha-boldenone (alpha-BOL). In a second study, urine samples negative to alpha-BOL were collected from eight veal calves, but became positive after deliberate faecal contamination. In a third study, data obtained from the Italian RNP (Residual National Program) indicated that 18.1% of 3295 urine samples collected using the zootechnical apron were positive for alpha-BOL and 2.1% for beta-boldenone (beta-BOL), whilst of 902 samples collected using the kettle, beta-BOL was not detected in any samples and only 0.2% were positive to alpha-BOL, in concentrations lower than 2 ng ml(-1). These results further support the supposition that faecal contamination of the urine during sample collection can lead to false-positive results during boldenone analysis.


Asunto(s)
Carcinógenos/análisis , Heces/química , Contaminación de Alimentos/análisis , Testosterona/análogos & derivados , Testosterona/análisis , Animales , Bovinos , Reacciones Falso Positivas , Hidrólisis , Carne/análisis , Testosterona/orina
19.
J Vet Pharmacol Ther ; 27(4): 247-54, 2004 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15305854

RESUMEN

Radioligand binding studies and functional assays on isolated smooth muscle preparations were performed in order to obtain a biochemical and functional characterization of the beta-adrenoceptor (beta-AR) subtypes involved in regulation of the smooth muscle relaxation of the calf's common digital artery. The results indicate that the common digital artery possesses two beta-AR populations (40% beta(1) and 60% beta(2)) and the beta(2)-subtype appears to predominate as far as function is concerned. Only the beta(2)-AR agonists clenbuterol and fenoterol caused dose-related relaxant effects, antagonized by propranolol, when tested in preparations precontracted both with PGF(2alpha) (1.4 x 10(-5) m) and noradrenaline (1.2 x 10(-6) m). In noradrenaline precontracted preparations the beta(1)-AR selective agonists dobutamine and xamoterol caused vasodilation which was not antagonized by (+/-)propranolol. While the functional relaxant effects of dobutamine may be attributed to its potent competitive alpha-AR blocking activity, further investigations are required to explain the effect of xamoterol. The vasodilator effect of (+/-)isoproterenol was irregular. The recorded contractile effects, mainly at dosages greater than 10(-6) m, suggest the loss of drug selectivity for beta-AR and alpha-AR activation. Indirect evidence indicates that the alpha-adrenoceptor (alpha-AR) population in this tissue which produces a strong contraction is functionally dominant over the beta-AR, suggesting limited therapeutic benefit for beta-AR drugs to control blood flow disorders in the calf's distal limb.


Asunto(s)
Agonistas Adrenérgicos beta/farmacología , Antagonistas Adrenérgicos beta/farmacología , Arterias/efectos de los fármacos , Enfermedades de los Bovinos/fisiopatología , Receptores Adrenérgicos beta/efectos de los fármacos , Agonistas Adrenérgicos beta/administración & dosificación , Antagonistas Adrenérgicos beta/administración & dosificación , Animales , Animales Recién Nacidos , Bovinos , Relación Dosis-Respuesta a Droga , Femenino , Miembro Anterior/irrigación sanguínea , Cojera Animal/fisiopatología , Masculino , Relajación Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos
20.
Equine Vet J ; 32(2): 119-24, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10743967

RESUMEN

We used isolated equine digital arteries to study the vasodilatory mechanism of isoxsuprine, and fowl caecum preparations to investigate the affinity of the drug for beta-adrenoceptors. Isoxsuprine is a potent vasodilator of arterial smooth muscle that has been precontracted by an alpha-adrenoceptor agonist such as noradrenaline (log EC50 = -6.33 [-5.98; -6.68]). The present study indicates that its effect is due to alpha-adrenoceptor blockade since: (1) after a long lasting exposure to cumulative doses of isoxsuprine the vasoconstricting action of noradrenaline cannot be restored; (2) isoxsuprine does not promote relaxation on preparations precontracted by PGF2alpha; (3) isoxsuprine shifts the dose-response curve of noradrenaline to the right; and (4) its affinity (pK(B) = 6.90 [6.60; 7.20]) in this experiment is comparable to that in noradrenaline-precontracted preparations and is 14 times lower than that of the selective alpha1-adrenergic antagonist prazosin [pK(B) = 8.04 (7.40; 8.68]). The affinity of isoxsuprine for beta-adrenoceptors was 100 times lower than that of isoprenaline when tested on fowl caecum. This preparation has a large beta-adrenoceptor and negligible alpha-adrenoceptor population concerned with the control of smooth muscle motility. Our data suggest that the alpha-mediated effect of isoxsuprine on horse arterial smooth muscle is due to higher affinity of the drug for alpha- than beta-adrenoceptors rather than low concentration or functionality of beta-sites at this site. According to these data, pure beta2-agonists seem to be more profitable tools to determine vasodilation of the arterial bed in horses legs.


Asunto(s)
Agonistas Adrenérgicos beta/farmacocinética , Arterias/metabolismo , Miembro Anterior/irrigación sanguínea , Caballos/metabolismo , Isoxsuprina/farmacocinética , Músculo Liso Vascular/metabolismo , Vasodilatación , Antagonistas Adrenérgicos alfa/metabolismo , Agonistas Adrenérgicos beta/administración & dosificación , Animales , Pollos , Relación Dosis-Respuesta a Droga , Isoproterenol/metabolismo , Isoxsuprina/administración & dosificación , Receptores Adrenérgicos beta/metabolismo
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