In vitro investigations of β-agonist accumulation in the eye

Dürsch, I.; Meyer, H. H. D.; Jäger, Stefan

doi:10.1016/0003-2670(93)80291-r

Cited by 17 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The range of levels in liver tissue was remarkably small, which also applies for the other groups in the experiment (not shown here). As was to be expected from other studies (BLANCHFLOWER et al, 1993;DURSCH et al, 1993;ELLIOTT et al, 1995) with clenbuterol only, the levels in the combined retina and pigments from the underlymg choroid were relatively higher, although large deviations were observed.…”

Section: Levels O J Beta-agonists In Various Matrikessupporting

confidence: 85%

Combinations of Growth Promoters in Veal Calves: Consequences for Screening and Confirmation Methods

Groot¹,

Schilt²,

Ossenkoppele³

et al. 1998

Journal of Veterinary Medicine Series A

View full text Add to dashboard Cite

This study investigates the influence of low dosages of /I-agonists combined with other growth promoters on screening and confirmation methods in male veal calves. Five groups of four calves were treated for 6 weeks with combinations of low dosages of B-agonists (BAG, clenbuterol, mabuterol and mapenterol, 0.4pg/kg each twice daily) in combination with 17P-estradiol (E2, 5mg per animal per 14 days), methylthiouracil (MTU, 2.857mg/kg bw twice daily) and dexamethasone @EX, 4mg per animal per 10 days during the last 20 days of treatment). Another group of four untreated animals served as controls. The weight and sue of the thymus was reduced in the DEX group, the MTU group showed enlarged thyroids. Histologically the prostates showed vacuolar degeneration in the BAG animals and metaplasia in the E2 group. Some vacuolization was also observed in the controls. The testis.showed impaired development in all treatment groups, E2 leading to the most severe changes. DEX led to cortical atrophy of the thymus. MTLJ induced hyperplastic changes in the thyroid. These results indicate that comedication does not markedly affect the histological changes induced in the hormonal target tissues. For screening purposes histology of the prostate can be used as a marker for oestrogens, whereas the weight of the thymus and thyroid can be used as an indication for the use of corticosteroids and thyreostatics, respectively. Vacuolization in the prostate appeared no reliable indication for B-agonists. Samples of urine, faeces, liver and eye (cetina/choroid) were analysed for 1-agonists. E2 significantly increased the levels of all 8-agonists in the liver and faeces, whereas DEX significantly reduced these levels. These observations show that additional medication with different groups of growth promoters can markedly alter the excretion of 8-agonists and thus influence (regulatory) control.

show abstract

Section: Levels O J Beta-agonists In Various Matrikessupporting

confidence: 85%

Combinations of Growth Promoters in Veal Calves: Consequences for Screening and Confirmation Methods

Groot¹,

Schilt²,

Ossenkoppele³

et al. 1998

Journal of Veterinary Medicine Series A

View full text Add to dashboard Cite

show abstract

“…Various recent studies [6][7][8][9] have shown the potential for pigmented tissues in control programmes for unauthorised substances in animal husbandry, particularly clenbuterol, due to the selective fixation which occurs between melanin and these substances and remains stable. The retina is, therefore, a widely used matrix in most clenbuterol determination techniques, such as immunological tests, radioimmunoassay [6] or enzyme immunoassay [7][8][9][10][11], and in chromatographic techniques such as: HPLC with UV [12] or electrochemical [13] detection and GC -MS [14], after various extraction or purification procedures, such as liquid-liquid extraction [13][14] and solid-phase extraction [ 12]. Diphasic dialysis enables selective and efficient extraction from aqueous media of compounds of low molecular mass, using organic solvents and without need for complementary purifying procedures; it has already been utilised to extract clenbuterol from urine [ 15] and liver [16][17].…”

Section: 5-dichloro-a-[(tert-butylamino) Methyl] Benzyl Alco-mentioning

confidence: 99%

Diphasic dialysis extraction technique for clenbuterol determination in bovine retina by gas chromatography-mass spectrometry

et al. 1999

View full text Add to dashboard Cite

“…However, after a withdrawal time of 3-4 days, the concentration of b-agonists is below the limit of detection of most assays, which makes this sample material suitable only for detection during treatment and less suitable for the detection of illegal use. 2 The eye has been described as the most accumulating tissue for b-agonists 3 and analysis of retinal extracts has been shown to extend the detection period to about 20 weeks. 4 However, eyes can only be sampled at the slaughterhouse.…”

Section: Introductionmentioning

confidence: 99%

A fast immunoassay for the screening of β-agonists in hair†

Haasnoot¹,

Stouten²,

Schilt³

et al. 1998

Analyst

View full text Add to dashboard Cite

Hair has been shown to be an excellent site for the accumulation of clenbuterol residues. Compared with other matrices, hair sampling is very easy and this might result in large numbers of samples. In this study, a simple digestion-extraction procedure was combined with a sensitive clenbuterol ELISA, which resulted in an easy screening procedure suitable for the detection of at least four beta-agonists. Hair from untreated cows (n = 40) resulted in low blank levels (0.9 +/- 0.7 and 0.5 +/- 0.2 ng g-1 for black and white hair, respectively). The detection limits for clenbuterol, bromobuterol, mapenterol and mabuterol were determined as 1-1.5 ng g-1 for white and 3-4 ng g-1 for black hair. The accumulation of mabuterol and mapenterol in black and white hair from treated calves was demonstrated by GC-MS. The screening assay is not suitable for the detection of cimbuterol (owing to the low extraction efficiency) and for salbutamol and terbutaline (owing to the low cross-reactivity of the antibodies used for the ELISA and the low extraction efficiency). Black hair samples from cows treated with clenbuterol were still found to be positive (> 5 ng g-1) at 23 weeks after treatment. The fast screening procedure is a powerful means to detect and track the illegal use of clenbuterol, bromobuterol, mabuterol and mapenterol in animal production.

show abstract

In vitro investigations of β-agonist accumulation in the eye

Cited by 17 publications

References 4 publications

Combinations of Growth Promoters in Veal Calves: Consequences for Screening and Confirmation Methods

Combinations of Growth Promoters in Veal Calves: Consequences for Screening and Confirmation Methods

Diphasic dialysis extraction technique for clenbuterol determination in bovine retina by gas chromatography-mass spectrometry

A fast immunoassay for the screening of β-agonists in hair†

Contact Info

Product

Resources

About