[Doping relevant substances in horse feed]. / Dopingrelevante Substanzen in Futtermitteln für Pferde.

INTRODUCTION: Horse feed material of Swiss and foreign production available on the Swiss market was tested with regard to possible contamination with 7 different alkaloids, atropine and colchicine. Twenty-eight feed samples as well as 2 poppy seed samples were analyzed. Out of 28 feed samples 18 were positive for prohibited substances in Equestrian sports. The concentration of prohibited substances was in none of the samples high enough to cause an effect on the body of the horse. The poppy seed sample, which was obtained by conventional harvesting and cleaning methods, contained a very high Morphine concentration compared to the sample which was harvested by hand. Despite high quality standards a contamination with prohibited substances in horse feed cannot be excluded.

INTRODUCTION: Divers aliments pour chevaux de provenance indigène et étrangère disponibles sur le marché suisse ont été examinés quant à une éventuelle contamination par 7 alcaloïdes différents ainsi que par l'atropine et la colchicine. On a analysé 28 échantillons de fourrages ainsi que 2 échantillons de graines de pavot provenant de cultures suisses. Dix-huit des vingt-huit échantillons contenaient des substances pouvant avoir une importance en matière de dopage dans les sports équestres. La concentration des substances recherchées n'était, dans aucun des échantillons de fourrages, assez élevée pour qu'on puisse tabler avec un effet sur le corps du cheval. L'échantillon de graines de pavot produites avec les techniques usuelles de récolte et de nettoyage présentait, par rapport à celui composé de graines récoltées à la main, un taux de morphine inhabituellement élevé. La présente étude de 28 échantillons d'aliments démontre qu'une contamination avec des substances ayant une importance en matière de dopage ne peut pas être exclue, même avec des standards de qualité élevés.

Experimentally determined weight matrix definitions of the initiator and TBP binding site elements of promoters.

The basal elements of class II promoters are: (i) a-30 region, recognized by TATA binding protein (TBP); (ii) an initiator (Inr) surrounding the start site for transcription; (iii) frequently a downstream (+10 to +35) element. To determine the sequences that specify an Inr, we performed a saturation mutagenesis of the Inr of the SV40 major late promoter (SV40-MLP). The transcriptional activity of each mutant was determined both in vivo and in vitro. An excellent correlation between transcriptional activity and closeness of fit to the optimal Inr sequence, 5'-CAG/TT-3', was found to exist both in vivo and in vitro. Employing a neural network technique we generated from these data a weight matrix definition of an Inr that can be used to predict the activity of a given sequence as an Inr. Using saturation mutagenesis data of TBP binding sites we likewise generated a weight matrix definition of the -30 region element. We conclude the following: (i) Inrs are defined by the nucleotides immediately surrounding the transcriptional start site; (ii) most, if not all, Inrs are recognized by the same general transcription factor(s). We propose that the mechanism of transcription initiation is fundamentally conserved, with the formation of pre-initiation complexes involving the concurrent binding of general transcription factors to the -30, Inr and, possibly, downstream elements of class II promoters.