Determination of anthocyanins in the urine of patients with colorectal liver metastases after administration of bilberry extract

Anthocyanins possess cancer chemopreventive properties in preclinical models. Their clinical pharmacology is only poorly understood. In this pilot study, anthocyanins and their metabolites were analysed in the urine of two patients with colorectal liver metastases. They received a single dose of 1.88 g standardized bilberry extract (mirtoselect) via either nasogastric or nasojejunal tube intra‐operatively during liver resection. HPLC‐MS/MS and HPLC‐UV analysis showed there were more anthocyanins and metabolites in the urine of the patient who received mirtoselect via the stomach than via the jejunum. This result is consistent with information obtained in rodents which suggests the stomach is the predominant site for anthocyanin absorption. Copyright © 2010 John Wiley & Sons, Ltd.     

Metabolism studies of casticin in rats using HPLC‐ESI‐MSn

Casticin (3′,5‐dihydroxy‐3, 4′,6,7‐tetramethoxyflavone) has been revealed to possess various kinds of pharmacological activities, including immunomodulatory, anti‐hyperprolactinemia, anti‐tumor and neuroprotetective activities. In order to gain an understanding of the biotransformation of casticin in vivo, a systematic method based on liquid chromatography–electrospray ionization tandem mass spectrometry (LC‐ESI‐MSⁿ) was developed to identify the metabolites of casticin in rats after oral administration of single dose of casticin at 200 mg/kg. By comparing their changes in molecular masses (ΔM), retention times and spectral patterns with those of the parent drug, the parent compound and 25 metabolites were identified in rat plasma, urine and six selected tissues. This is the first systematic metabolism study of casticin in vivo. The results indicated that methylation, demethylation, glucuronidation and sulfation were the main biotransformation pathways of casticin in vivo. Copyright © 2012 John Wiley & Sons, Ltd.     

Separation and detection of doxylamine and its rhesus monkey urinary metabolites by high resolution gas chromatography utilizing nitrogen/phosphorus detection

A high resolution gas chromatographic method is described for the separation of rhesus monkey urinary metabolites of doxylamine with the use of on-column injection, a fused silica column (DB-1701), and nitrogen/phosphorus detection. An ancillary separation of doxylamine and six other antihistamines is also presented.     

Preliminary study to prepare a reference material of styrene metabolites – mandelic acid and phenylglyoxylic acid – in human urine

 A preliminary batch of the reference material was prepared by freeze-drying pooled urine samples obtained from healthy persons occupationally exposed to styrene. Tests for homogeneity and stability were performed by determining urine concentrations of mandelic (MA) and phenylglyoxylic acids (PGA). The urinary MA and PGA concentrations were followed over an 8-month period using high performance liquid chromatography (HPLC). No changes of the concentration values were found. Pure PA and PGA from Merck and Fluka, respectively, were used for traceability purposes, because certified or standard reference materials for MA and PGA do not exist. Control material ClinChek-Urine Control (Recipe) was analysed simultaneously. The mean values of MA and PGA compared well with the means of control samples and fell within the control range. The certified values and their uncertainties were evaluated from the results of interlaboratory comparisons, homogeneity (277.0 ± 7.4 mg L⁻¹ for MA and 148.0 ± 4.7 mg L⁻¹ for FGA) and stability tests. The values are unweighted arithmetical averages of accepted results and their uncertainties are combined uncertainties enlarged by coefficient k=1, evaluated from the standard uncertainties of the interlaboratory comparison, homogeneity and stability tests. Received: 17 September 2002 Accepted: 1 November 2002 Acknowledgement This work was supported by the Internal Grant Agency of Ministry of Health of the Czech Republic (Grant NJ/6784–3). Presented at CERMM-3, Central European Reference Materials and Measurements Conference: The function of reference materials in the measurement process, May 30–June 1, 2002, Rogaška Slatina, Slovenia Correspondence to I. Šperlingová     

一个内生人口生育率可解的C-K模型

得到一个具有可解内生人口出生率的Ｃａｓｓ－Ｋｏｏｐｍａｎｓ经济增长模型．给出此模型在不同劳动和资本的结合方式下存在唯一最优增长轨道和稳态解的条件．最后讨论存在多重最优增长轨道和多重稳态解的可能性态和文中主要结果的经济意义．     

Stereochemical analysis of the 3α‐ and 3β‐hydroxy metabolites of tibolone through NMR and quantum‐chemical investigations. An experimental test of GIAO calculations

The configuration at C‐3 of the 3α‐ and 3β‐hydroxy metabolites of tibolone was studied by extensive application of one‐ and two‐dimensional ¹H and ¹³C NMR spectroscopy combined with molecular modeling performed at the B3LYP/6–31G(d) level. Using HF and DFT GIAO methods, shielding tensors of the two molecules were computed; comparison of the calculated NMR chemical shifts with the experimental values revealed that the density functional methods produced the best results for assigning proton and carbon resonances. Although steroids are relatively large molecules, the present approach appears accurate enough to allow the determination of relative configurations by using calculated ¹³C resonances; the chemical shift of pairs of geminal α/β hydrogen atoms can also be established by using calculated ¹H resonances. Copyright © 2002 John Wiley & Sons, Ltd.     

Development of an Ion-Pairing Liquid Chromatography Method for the Determination of Phenoxyacetic Herbicides and Their Main Metabolites: Application to the Analysis of Soil Samples

A modified ion-pairing liquid chromatography method is developed for the analysis of 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA) and their phenolic metabolites in water and soil samples. The separation and determination of all compounds of interest can be performed with a mobile phase containing 30% acetonitrile and 10 mM tetrabutylammonium hydroxide as the ion-pairing reagent. Separation of the two phenoxyacids is strongly affected by the pH of the mobile phase, which has to be buffered to pH 7.2 with phosphoric acid. The increase in the hydrophobicity of the sample solvent results in wider peaks for the two phenoxyacids, which reduces the resolution in their separation. The evaluation of different methanol:water solvent mixtures shows that no baseline separation for the two phenoxyacids is obtained when the methanol content in the mixture is higher than 60%.