Trans-resveratrol, but not other natural stilbenes occurring in food, carries the risk of drug-food interaction via inhibition of cytochrome P450 enzymes or interaction with xenosensor receptors

Resveratrol (RSV) is a stilbene phytochemical common in food and red wine. RSV inhibits cytochrome P450 CYP3A4 activity and interacts with the pregnane X receptor (PXR), the central regulator of drug/xenobiotic metabolizing enzyme expression. In this work, we comprehensively examined the effects of 13 stilbenes (trans- and cis-resveratrol, trans- and cis-piceatannol, oxyresveratrol, pterostilbene, pinostilbene, a,b-dihydroresveratrol, trans- and cis-trismethoxyresveratrol, trans-3,4,5,4'-tetramethoxystilbene, trans-2,4,3',5'-tetramethoxystilbene, trans-4-methoxystilbene), on CYP3A4 and CYP2B6 mRNA induction, and on CYP3A4/5, CYP2C8/9/19, CYP2D6, CYP2A6, CYP2E1, CYP1A2 and CYP2B6 cytochrome P450 enzyme activities. Expression experiments in five different primary human hepatocyte preparations, reporter gene assays, and ligand binding assays with pregnane X (PXR) and constitutive androstane (CAR) receptors were performed. Inhibition of cytochrome P450 enzymes was examined in human microsomes. We found that only polymethoxylated stilbenes are prone to significantly induce CYP2B6 or CYP3A4 in primary human hepatocytes via pregnane X receptor (PXR) interaction. Natural resveratrol derivatives such as trans- and cis-RSV, oxyresveratrol, pinostilbene and pterostilbene significantly inhibit CYP3A4/5 enzymatic activities; however, only trans-RSV significantly inhibits CYP3A4/5 activity (both testosterone 6β-hydroxylation and midazolam 1´-hydroxylation) in micromolar concentrations by a non-competitive mechanism, suggesting a potential risk of food-drug interactions with CYP3A4/5 substrates.

Improvements in antibiotic prescribing by community paediatricians in the Czech Republic

Repeated surveys among primary care paediatricians were performed annually from 1998 to 2002 in the Czech Republic. The task was to assess the prescription of antibiotics in treatment of respiratory infections in children. The results were evaluated in the light of existing guidelines and conclusions were used in a number of interventions aimed at reducing the inadequate use of antibiotics and hence preventing the potential increase of the antibiotic resistant bacteria. In addition, data on overall consumption of antibiotics in outpatient care and trends in the prevalence of resistant strains of Streptococcus pneumoniae and Streptococcus pyogenes are discussed.

The identification of a chlorinated MDMA

The abuse of the designer amphetamines such as 3,4-methylenedioxymethamphetamine (MDMA) is increasing throughout the world. They have become popular drugs at all night techno dance parties, and their detection is an important issue. The objective of the presented study was to identify an unknown compound detected by thin-layer chromatography (TLC) in the urine of an illicit drug abuser. The compound was isolated by TLC and analyzed by gas chromatography-mass spectrometry (GC-MS) in electron ionization (EI) and positive ion chemical ionization (PICI) mode to elucidate its chemical structure. Based on EI-MS and PICI-MS mass spectral data, the unknown compound was indicated to be a structure similar to MDMA, substituted by a single chlorine atom-a chlorinated MDMA (Cl-MDMA). To confirm the Cl-MDMA structure, the unknown compound was silylated, trifluoroacetylated, acetylated, heptafluorobutyrylated, and analyzed by GC-MS. The position of the chlorine atom cannot be assigned exactly from the mass spectral data presented here; however, we believe that the unknown compound could be 6-Cl-MDMA.

Dynamics of PCR-based diagnosis in patients with invasive meningococcal disease

Invasive meningococcal disease continues to be a life-threatening condition and rapid diagnosis is important for the administration of appropriate treatment. This study focused on the use of PCR for the diagnosis of meningococcal aetiology and the dynamics of PCR-based diagnosis over time in various biological samples. Sixty cerebrospinal fluid (CSF) and 144 serum samples collected during the first week of hospitalisation from 37 patients with laboratory-confirmed invasive meningococcal disease were investigated. Overall, 91.9% of CSF samples and 45.9% of serum samples were PCR-positive, while culture of CSF and blood was positive for only 35% and 39% samples, respectively. Positive PCR results were obtained until day 7 with CSF and until day 5 with serum. It is therefore recommended that samples for molecular diagnosis should be collected early in the course of suspected invasive meningococcal disease.

Evaluation of urinary dihydrocodeine excretion in human by gas chromatography-mass spectrometry

Urinary metabolic pattern after the therapeutic peroral dose of dihydrocodeine tartrate to six human volunteers has been explored. Using the GC-MS analytical method, we have found that the major part of the dose administered is eliminated via urine within the first 24 h. However, the analytical monitoring of dihydrocodeine and its metabolites in urine was still possible 72 h after the dose was administered. The dihydrocodeine equivalent amounts excreted in urine in 72 h ranged between 32 and 108% of the dose, on average 62% in all individuals. The major metabolite excreted into urine was a 6-conjugate of dihydrocodeine, then in a lesser amount a 6-conjugate of nordihydrocodeine (both conjugated to approximately 65%). The O-demethylated metabolite dihydromorphine was of a minor amount and was 3,6-conjugated in 85%. Traces of nordihydromorphine and hydrocodone were confirmed as other metabolites of dihydrocodeine in our study. This information can be useful in interpretation of toxicological findings in forensic practice.