P Dobrocký

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1. Caffeine is widely used as an in vivo probe for CYP1A2; the distribution/activity of this enzyme is reported to be reflected by metabolic ratios. 2. Several metabolic ratios using different combinations of urinary metabolites have been used to measure CYP1A2, with varying conclusions on its distribution. 3. A mathematical comparison of five metabolic(More)
1. Caffeine has been used to determine acetylator phenotype for some 15 years but the interpretation of metabolic ratios with this substance raises theoretical and methodological issues. 2. N-acetyltransferase type 2 (NAT2) status was assessed in 23 young healthy subjects using both caffeine overnight and spot urine samples, and sulphadimidine. 3. Frequency(More)
Caffeine is a popular compound for phenotyping individuals for CYP4501A2, xanthine oxidase (XO) and N-acetyltransferase (NAT) utilising urinary metabolites. The analysis is complex since at least thirteen metabolites are excreted by man. Past methods have been less than satisfactory in that either not all the metabolites have been resolved and/or(More)
Using perfusion method the reactivity of rabbit femoral and ear arteries was investigated following the administration of rising noradrenaline doses in four consecutive intervals. Progressive increase of vasoconstrictive activity of vessel segments was found. Results of histological examination showed a progressive de-endothelialization of perfused vessels.(More)
Patients with familial adenomatous polyposis (FAP) and age and sex matched controls were tested for cytochrome P4501A2 (CYP1A2), N-acetyltransferase, and xanthine oxidase activities using caffeine urinary metabolites as a discriminator. FAP patients showed significant underactivity of N-acetyltransferase (which inactivates some carcinogens) and significant(More)
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