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The stearoyl-CoA desaturase (SCD) activity is involved in regulation of metabolism, energy storage, and membrane fluidity. However, only few cellular assays have been developed. We describe a simple and robust method to quantitate SCD activity and its inhibition in primary rat hepatocytes. Hepatocytes assimilate stearic acid, with or without modification by SCD, into its lipid pool. To measure the extent of this conversion primary rat hepatocytes were cultivated 4h or overnight with [1-(14)C]18:0 and extracellular fatty acids were washed out. Total cell lipids were then hydrolyzed and extracted. Recoveries of 18:0 were secured with a modified Folch method by addition of 0.1% Triton X-114 to the samples. The extracted fatty acids were dissolved in 85% ethanol and separated by reverse phase HPLC, which took 10 min including column recovery time. [1-(14)C]18:0 and [1-(14)C]18:1(n9) were detected and quantified by on-line flow scintillation analysis. Incubation of the cells with SCD inhibitors resulted in decreased ratios of 18:1/18:0 in dose-dependent manners. The improvements enabled us to establish a novel robust assay based solely on HPLC analysis of cellular SCD activity, which was developed in 12-well format., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

Liver microsome and hepatocyte-mediated biotransformation of three oral antileishmanial 2-substituted quinolines were investigated. One quinoline contains an n-propyl group (1) and the other a propenyl chain functionalized at the gamma position either by a nitrile (2) or an alcohol (3). The different isoforms of rat cytochrome P450 responsible for biotransformation of 1 were also investigated. Compounds 2 and 3 mainly reacted with glutathione, preventing further metabolism. Compound 3 however, the reaction being reversible, could be released from glutathione and take alternative reaction pathways. Microsomal incubations of 1 mainly led to hydroxylation of the side chain, involving many cytochromes, predominantly CYP2B1, CYP2A6 and CYP1A1 (at more than 80%). In contrary, minor metabolites hydroxylated on the quinoline ring involved a few cytochromes. The hydroxylated products of 1 were conjugated with glucuronic acid in rat hepatocyte incubations.

Metabolic fingerprinting of biofluids like urine is a useful technique for detecting differences between individuals. With this approach, it might be possible to classify samples according to their biological relevance. In Part 1 of this work a method for the comprehensive screening of metabolites was described, using two different liquid chromatography (LC) column set-ups and detection by electrospray ionization mass spectrometry (ESI-MS). Data pretreatment of the resulting data described in is needed to reduce the complexity of the data and to obtain useful metabolic fingerprints. Three different approaches, i.e., reduced dimensionality (RD), MarkerLynx, and MS Resolver, were compared for the extraction of information. The pretreated data were then subjected to multivariate data analysis by partial least squares discriminant analysis (PLS-DA) for classification. By combining two different chromatographic procedures and data analysis, the detection of metabolites was enhanced as well as the finding of metabolic fingerprints that govern classification. Additional potential biomarkers or xenobiotic metabolites were detected in the fraction containing highly polar compounds that are normally discarded when using reversed-phase liquid chromatography.

Complex biological samples, such as urine, contain a very large number of endogenous metabolites reflecting the metabolic state of an organism. Metabolite patterns can provide a comprehensive signature of the physiological state of an organism as well as insights into specific biochemical processes. Although the metabolites excreted in urine are commonly highly polar, the samples are generally analyzed using reversed-phase liquid chromatography mass spectrometry (RP-LC/MS). In Part 1 of this work, a method for detecting highly polar metabolites by hydrophilic interaction liquid chromatography-electrospray ionization mass spectrometry (HILIC/ESI-MS) is described as a complement to RP-LC/ESI-MS. In addition, in an accompanying paper (Part 2), different multivariate approaches to extracting information from the resulting complex data are described to enable metabolic fingerprints to be obtained. The coverage of the method for the screening of as many metabolites as possible is highly improved by analyzing the urine samples using both a C(18) column and a ZIC-HILIC column. The latter was found to be a good alternative when analyzing highly polar compounds, e.g., hydroxyproline and creatinine, to columns typically used for reversed-phase liquid chromatography.

The aim of this study was to investigate the quality of Swedish-language breast cancer information available on the Internet. The questions explored were the extent and type of breast cancer information available, the coverage and correctness of that information, and whether the websites fulfilled the European Commission quality criteria for health-related websites. Three search engines were used to find websites containing medical information on breast cancer. An oncologist then evaluated the 29 relevant sites. Only seven of these were judged suitable for breast cancer patients. The coverage and correctness of the medical information varied considerably. None of the websites fulfilled the European Commission quality criteria. Therefore, considerable effort will be required before the Internet can serve as a valuable and up-to-date source of information on breast cancer for both professionals and laypersons. Our findings broadly match the results of earlier studies of English-language websites.