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Michalke B.,Helmholtz Center Munich | Rossbach B.,Johannes Gutenberg University Mainz | Goen T.,Friedrich - Alexander - University, Erlangen - Nuremberg | Schaferhenrich A.,Friedrich - Alexander - University, Erlangen - Nuremberg | Scherer G.,ABF Analytisch Biologisches Forschungslabor GmbH
International Archives of Occupational and Environmental Health | Year: 2014

Purpose: Human biomonitoring (HBM) implies the assessment of internal exposure to hazardous substances by measuring the substances, their metabolites or reaction products, as well as effect parameters in human body fluids. Along with blood, plasma and urine, saliva is of increasing interest as an alternative matrix for HBM. Methods: This paper reviews studies that measure salivary background levels of hazardous substances, elevated levels after environmental or occupational exposure, as well as references which deal with physiological and toxicokinetic behaviour of saliva and salivary parameters, respectively. Results: The studies revealed that the determination of biomarkers in saliva is a promising approach for HBM, even if only few substances showed a satisfying correlation with exposure data or established biomonitoring matrices such as blood, plasma and urine. Saliva has been proven to be particularly suitable for substances of low molecular weight such as organic solvents, selected pesticides, cotinine, and for some specific trace elements. Besides several advantages, serious problems and limitations were identified. Above all, the complex interactions between substance properties, sampling procedure, sample preparation, measurement techniques or individual factors, and the salivary analyte level are discussed. Conclusions: A major conclusion of the review is that more scientific studies are needed in order to systematically collect data on parameters, influencing salivary analyte levels. Crucially required is a harmonisation of the sampling as well as the sample preparation techniques and procedures, which is indispensable to achieve an overall comparability and interpretability of salivary biomarker levels. © 2014 Springer-Verlag Berlin Heidelberg. Source


Scherer G.,ABF Analytisch Biologisches Forschungslabor GmbH
Beitrage zur Tabakforschung International/ Contributions to Tobacco Research | Year: 2014

Individual uptake of tobacco smoke constituents by smoking is highly variable in cigarette smokers and cannot be predicted by smoking behaviour variables and machinederived smoke yields. It is well established that uptake of smoke constituents is best described by a series of biomarkers of exposure (BOEs) such as metabolites of nicotine, tobacco-specific nitrosamines (TSNAs), polycyclic aromatic hydrocarbons (PAHs), aromatic amines, benzene, 1,3-butadiene, acrolein, hydrogen cyanide, 2,5-dimethylfuran and other smoke constituents.The purpose of this review is to investigate the relationship between BOE levels and machine-derived smoking yields on the basis of published data. The influence of other smoking behaviour variables, in particular the number of cigarettes smoked per day (CPD) and smoking topography (puffing and inhalation patterns) is also considered, provided suitable data are available.Twenty eight (28) published studies, which report data on machine-derived smoke yields and biomarker concentrations in body fluids of smokers of these products were identified. In total, 33 different BOEs were applied in these studies. Important properties of the BOEs used in the further evaluation were described and discussed.In almost all studies selected, data for CPD were reported. In only a few studies, puffing and inhalation profiles have been determined so that no systematic evaluation of the association between smoking topography and BOE levels was possible. In the studies evaluated, no statistically significant association between daily cigarette consumption (CPD) and smoke yields was observed. This clearly indicates that low machine-derived yields were not compensated by increasing the daily cigarette consumption. As expected, positive and statistically significant relationships were found between CPD and BOE levels for most of the biomarkers investigated.Bi- and multivariate linear regressions were calculated for the relationships between BOE levels (dependent variable) and machine-derived yields as well as CPD (independent variables). Whenever possible, results from various studies were combined (this was only possible, when identical biomarkers and yield types were available). Aggregation of the results from all studies independent of BOE and yield type used is feasible on the basis of relative BOE and yield levels. The multivariate linear regression models obtained reveal that both CPD and machine-derived yields are significant predictors of the measured BOE levels. The models predict that, on average, a 50% reduction in CPD or yield are accompanied by a 33 or 15% reduction, respectively, in smoke uptake, as measured by various BOEs.Taken together, the evaluated data from the literature show that lower machine-derived yields lead to a reduced uptake of smoke constituents. The reduction is statistically significant, but substantially lower than the decrease in machinederived yields. © 2014,Institut Fur Takforschung GMBH. All right reserved. Source


Ecker J.,ABF Analytisch Biologisches Forschungslabor GmbH
Journal of Separation Science | Year: 2012

Eicosanoids are potent lipid mediators involved in numerous physiological and pathophysiological processes. Precursors are polyunsaturated fatty acids liberated from membrane phospholipids. Thus, profiling and quantification of these molecules has gained a lot of attention during last years. Eicosanoids and phospholipids are commonly profiled by LC-MS/MSbecause this technique allows accurate quantification within acceptable run-times. This article therefore focuses on liquid chromatography and the ESI-MS/MS analysis of proinflammatory lipid mediators, particularly arachidonic acid (C20:4) derived eicosanoids and their precursors phospholipids. Recent analytical developments for quantification of these compounds are highlighted and analytical challenges are discussed. Furthermore, applications such as the use of these molecules as biomarkers are presented. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Scherer G.,ABF Analytisch Biologisches Forschungslabor GmbH | Lee P.N.,P.N. Lee Statistics and Computing Ltd.
Regulatory Toxicology and Pharmacology | Year: 2014

The extent of compensation when switching to lower yield cigarettes is important for assessing risk of reduced yield products. Both completeness of and reasons for compensation are judged differently in the scientific and health community. We quantified compensation in a meta-analysis of suitable cross-sectional and brand-switching studies. For each dataset, we derived a compensation index (CI), 1 indicating complete and 0 no compensation. Meta-analyses provided overall estimates. We also reviewed evidence on compensation for nicotine and other factors. The unweighted mean CI (95% confidence interval) was 0.628 (0.513 to 0.742) from 38 estimates from 26 cross-sectional studies, and 0.723 (0.651 to 0.796) from 23 estimates from 19 brand-switching studies. Inverse-variance weighted estimates were 0.781 (0.720 to 0.842) and 0.744 (0.682 to 0.806). Brand-switching data indicate smokers compensate more completely over a narrower yield range. Smokers predominantly compensate by changing puffing volume, and little by changing cigarette consumption. The findings support compensation for nicotine, but other factors may also be relevant. Further investigation is needed using larger studies and different approaches to elucidate their role. We conclude that smokers switching to lower-yield cigarettes only partially compensate. Pharmacological nicotine effects are important, but other factors, including cigarette draw resistance, sensory effects of nicotine and conditioned stimuli may also contribute. © 2014 Elsevier Inc. Source


Ecker J.,University of Regensburg | Ecker J.,ABF Analytisch Biologisches Forschungslabor GmbH | Scherer M.,University of Regensburg | Scherer M.,Nestle | And 2 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2012

So far the most frequently used method for fatty acid (FA) analysis is GC coupled to flame ionization detector (FID). However, GC-FID does not allow profiling of FA synthesis and metabolism using stable isotopes. Here we present a rapid and sensitive GC-MS method for determination of fatty acid methyl esters (FAMEs). Fatty acid methylation was carried out by transesterification with acetyl-chloride and methanol. FAME separation applies a short and polar cyano-column resulting in an analysis time of 17.2. min. Separation was achieved for positional and geometrical (. cis/. trans) isomers with chain lengths between C8 and C28. Partial overlap of FAMEs (e.g. for C20:2 (. n-6) and C21:0) could be resolved using selected ion monitoring (SIM). The precisions for human plasma samples were better than 10% coefficient of variation (CV) except for very low abundant FAs and LODs were in the low femtomol range on column. The developed GC-MS method also allows quantification of conjugated FAs such as conjugated linoleic acid (CLA) isomers because lowering the derivatization temperature from 95. °C to room temperature prevented cis to trans double bond isomerization. Finally, profiling of fatty acid synthesis and metabolism was exemplified with stable isotope labeling of macrophages using fatty acid precursors or deuterated fatty acids. In summary, we present a fast and robust GC-MS method for fatty acid profiling of positional and geometrical isomers including CLAs as well as very long chain fatty acids (VLCFAs). The method is suitable for both clinical studies and basic research including application of stable isotope compounds. © 2012 Elsevier B.V. Source

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