Metabolites In Biological Specimens Research Articles

Probing and gauging of D-Penicillamine xenobiotics in hepatic Wilson disease patients

D-penicillamine (PA) is the primary chelator of choice to treat Wilson disease (WD). There are limitations in obtaining comprehensive data on PA metabolites in biological specimens by conventional approaches. Hence, the aim of the present was to identify the major hepatic PA metabolites and draw clear conclusions of the drug's xenobiotic in WD. Urine samples were collected from children with hepatic WD (n = 63, aged 14.8 ± 4 years) 5 h after PA administration (16.3 ± 3.8 mg/kg/day) and age-matched healthy volunteers comprised as controls (n = 30). High-resolution 800 MHz nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry was applied to reveal unambiguous appraisals of different excretory by-products of PA metabolism. Four new products comprising penicillamine disulphide (PD), penicillamine cysteine disulphide (PCD), S-methyl penicillamine (SMP), and N-acetyl penicillamine (NAP) of PA xenobiotic metabolites were identified using high-resolution NMR spectroscopy. Quantitative levels of PCD and SMP were approximately three-fold higher than those of PD and NAP, respectively. High-resolution NMR identifies the major PA metabolites with certainty. Reduction, sulfation, and methylation are the predominant pathways of PA metabolism. There is a potential application for assessing therapeutic monitoring of chelation in hepatic WD.

Whole Body Distribution of Labile Coenzymes and Antioxidants in a Mouse Model as Visualized Using 1H NMR Spectroscopy.

Coenzyme A, acetyl coenzyme A, coenzymes of cellular energy, coenzymes of redox reactions, and antioxidants mediate biochemical reactions fundamental to the functioning of all living cells. There is an immense interest in measuring them routinely in biological specimens to gain insights into their roles in cellular functions and to help characterize the biological status. However, it is challenging to measure them ex vivo as they are sensitive to specimen harvesting, extraction, and measurement conditions. This challenge is largely underappreciated and carries the risk of grossly inaccurate measurements that lead to incorrect inferences. To date, several efforts have been focused on alleviating this challenge using NMR spectroscopy. However, a comprehensive solution for the measurement of the compounds in a wide variety of biological specimens is still lacking. As a part of addressing this challenge, we demonstrate here that the total pool of each group of unstable metabolites offers a starting place for the representation of labile metabolites in biological specimens. Based on this approach, in this proof-of-concept study, we determine the distribution of the labile compounds in different organs including heart, kidney, liver, brain, and skeletal muscle of a mouse model. The results were independently validated using different specimens and a different metabolite extraction protocol. Further, we show that both stable and unstable metabolites were distributed differentially in different organs, which signifies their differential functional roles, the knowledge of which is currently lacking for many metabolites. Intriguingly, the concentration of taurine, an amino sulfonic acid, in skeletal muscle is >30 mM, which is the highest for any metabolite in a mammalian tissue known to date. To the best of our knowledge, this is the first study to profile the whole body distribution of the labile and other high-concentration metabolites using NMR spectroscopy. The results may pave ways for gaining new insights into cellular functions in health and diseases.

Simultaneous quantification of vitamin E and vitamin E metabolites in equine plasma and serum using LC-MS/MS.

Vitamin E deficiencies can impact normal growth and development in humans and animals, and assessment of circulating levels of vitamin E and its metabolites may be an important endpoint for evaluation. Development of a sensitive method to detect and quantify low concentrations of vitamin E and metabolites in biological specimens allows for a proper diagnosis for patients and animals that are deficient. We developed a method to simultaneously extract, detect, and quantify the vitamin E compounds alpha-tocopherol (α-TP), gamma-tocopherol (γ-TP), alpha-tocotrienol (α-TT), and gamma-tocotrienol (γ-TT), and the corresponding metabolites formed after β-oxidation of α-TP and γ-TP, alpha-carboxymethylbutyl hydroxychroman (α-CMBHC) and alpha- or gamma-carboxyethyl hydroxychroman (α- or γ-CEHC), respectively, from equine plasma and serum. Quantification was achieved through liquid chromatography-tandem mass spectrometry. We applied a 96-well high-throughput format using a Phenomenex Phree plate to analyze plasma and serum. Compounds were separated by using a Waters ACQUITY UPLC BEH C18 column with a reverse-phase gradient. The limits of detection for the metabolites and vitamin E compounds were 8-330 pg/mL. To validate the method, intra-day and inter-day accuracy and precision were evaluated along with limits of detection and quantification. The method was then applied to determine concentrations of these analytes in plasma and serum of horses. Alpha-TP levels were 3-6 µg/mL of matrix; the metabolites were found at much lower levels, 0.2-1.0 ng/mL of matrix.

Metabolomics: An Emerging Tool for Precision Medicine

BACKGROUND: Metabolomics is a developed technology that comprehensively analyzes the metabolites in biological specimens. It appears to be a prospective method in the practice of precision medicine.CONTENT: Metabolomic technologies currently surpass beyond the traditional clinical chemistry techniques. Metabolomic is capable to perform a precise analysis for hundreds to thousands of metabolites, therefore provide a detailed characterization of metabolic phenotypes and metabolic derangements that underlie disease, to represent an individual’s overall health status, furthermore to discover new precise therapeutic targets, and discovery of biomarkers, either for diagnosis or therapy monitoring purpose.SUMMARY: Adequate data processing and quantification methods are still needed to be developed to boost integrated -omics as a powerful clinical practice platform.KEYWORDS: metabolomic, precision medicine, phenotyping, biomarker, nutritional pattern

Overview of the major classes of new psychoactive substances, psychoactive effects, analytical determination and conformational analysis of selected illegal drugs

Abstract The misuse of psychoactive substances is attracting a great deal of attention from the general public. An increase use of psychoactive substances is observed among young people who do not have enough awareness of the harmful effects of these substances. Easy access to illicit drugs at low cost and lack of effective means of routine screening for new psychoactive substances (NPS) have contributed to the rapid increase in their use. New research and evidence suggest that drug use can cause a variety of adverse psychological and physiological effects on human health (anxiety, panic, paranoia, psychosis, and seizures). We describe different classes of these NPS drugs with emphasis on the methods used to identify them and the identification of their metabolites in biological specimens. This is the first review that thoroughly gives the literature on both natural and synthetic illegal drugs with old known data and very hot new topics and investigations, which enables the researcher to use it as a starting point in the literature exploration and planning of the own research. For the first time, the conformational analysis was done for selected illegal drugs, giving rise to the search of the biologically active conformations both theoretically and using lab experiments.

Detection of 28 Corticosteroids in Pharmaceutical and Proprietary Chinese Medicinal Products Using Liquid Chromatography-Tandem Mass Spectrometry.

With their potent anti-inflammatory effects, corticosteroids are popular adulterants in illicit health products for allergies, dermatitis and pain control. Their illegal supply over the counter is also a common practice for similar conditions. Prolonged, unsupervised usage of corticosteroids often leads to severe adverse effects including Cushing syndrome, adrenal insufficiency and immunosuppression. Confirming clinical suspicion of unsupervised corticosteroid usage is challenging. Apart from evaluating the adrenal function, identifying the concerned drug is the most direct proof of its consumption. While detecting corticosteroids or their metabolites in biological specimens is convincing evidence of their usage, such approach is analytically difficult. More importantly, this approach would not be useful if the patient has stopped taking the drug for some time-a situation that is often encountered clinically. We advocate a more direct approach by measuring corticosteroids in suspicious medicinal products. In the current study, a liquid chromatography-tandem mass spectrometry method for simultaneous detection of 28 corticosteroids in pharmaceutical and proprietary Chinese medicine products was developed and validated for the purpose. The method was applied to 388 cases of suspected unsupervised corticosteroids usage. Among 1,000 products tested, corticosteroids were found in 276 of them and confirmed the clinical suspicion.

Abstract P191: Metabolites Associated With Coffee Consumption and Incident Chronic Kidney Disease

Introduction: Several studies have found moderate coffee consumption to be inversely associated with chronic kidney disease (CKD), however the biological mechanisms underlying this benefit are unclear. Metabolomic studies allow for the characterization of metabolites in biological specimens and are useful for detecting biomarkers of coffee consumption and metabolic pathways underlying the association between coffee and CKD. Hypothesis: We hypothesized that metabolites altered by coffee consumption would be associated with CKD incidence. Methods: A total of 3,809 African-American and Caucasian ARIC study participants had measurements of serum metabolites: 373 metabolites in sample 1 and 758 metabolites in sample 2. Linear regression models were used to estimate cross-sectional associations between metabolites and average cups of coffee consumed per day. Cox regression models were used to estimate associations between coffee metabolites and incident CKD. Results: In sample 1, 13 metabolites were significantly and positively associated with coffee consumption (p<0.05/373=1.3х10 -4 ), one of which (hippurate) was inversely associated with incident CKD ( Table ). In sample 2, 29 metabolites were positively associated and 20 were negatively associated with coffee consumption (p<0.05/758=6.6х10 -5 ). All 13 metabolites detected in sample 1 were also significantly associated with coffee in sample 2. Higher levels of three metabolites (O-sulfo-L-tyrosine, erythritol, and N-acetylserine) were associated with lower intake of coffee and higher risk of incident CKD. Conclusions: We detected 13 candidate biomarkers of coffee consumption that replicated across two samples. Four metabolites, consisting of a food component (erythritol), chemical (O-sulfo-L-tyrosine), and compounds that are involved in the metabolism of benzoate (hippurate), glycine, serine, and threonine (N-acetylserine), may play contribute to the favorable health outcomes observed with coffee consumption.

Integration of single-cell RNA-seq data into population models to characterize cancer metabolism.

Metabolic reprogramming is a general feature of cancer cells. Regrettably, the comprehensive quantification of metabolites in biological specimens does not promptly translate into knowledge on the utilization of metabolic pathways. By estimating fluxes across metabolic pathways, computational models hold the promise to bridge this gap between data and biological functionality. These models currently portray the average behavior of cell populations however, masking the inherent heterogeneity that is part and parcel of tumorigenesis as much as drug resistance. To remove this limitation, we propose single-cell Flux Balance Analysis (scFBA) as a computational framework to translate single-cell transcriptomes into single-cell fluxomes. We show that the integration of single-cell RNA-seq profiles of cells derived from lung adenocarcinoma and breast cancer patients into a multi-scale stoichiometric model of a cancer cell population: significantly 1) reduces the space of feasible single-cell fluxomes; 2) allows to identify clusters of cells with different growth rates within the population; 3) points out the possible metabolic interactions among cells via exchange of metabolites. The scFBA suite of MATLAB functions is available at https://github.com/BIMIB-DISCo/scFBA, as well as the case study datasets.

LC-MS/MS-Based Metabolomics for Cell Cultures.

Metabolomics, a comprehensive analysis of metabolites in biological specimens (e.g., cells, body fluids, tissues, exhaled air, plants), offers promising tools in health, nutrition, biotechnology, and food sciences. Here we describe methods of LC-MS/MS-based analyses for cell metabolomics. Using methods employed in this section, over 1000 endogenous and exogenous metabolites can be detected, annotated, and quantified relatively by nontargeted analysis approach, whereas targeted metabolomics analysis enables us to quantify 188 endogenous metabolites.

Metabolomic changes in vertebrate host during malaria disease progression

Metabolomics refers to top-down systems biological analysis of metabolites in biological specimens. Phenotypic proximity of metabolites makes them interesting candidates for studying biomarkers of environmental stressors such as parasitic infections. Moreover, the host–parasite interaction directly impinges upon metabolic pathways since the parasite uses the host metabolite pool as a biosynthetic resource. Malarial infection, although not recognized as a classic metabolic disorder, often leads to severe metabolic changes such as hypoglycemia and lactic acidosis. Thus, metabolomic analysis of the infection has become an invaluable tool for promoting a better understanding of the host–parasite interaction and for the development of novel therapeutics. In this review, we summarize the current knowledge obtained from metabolomic studies of malarial infection in rodent models and human patients. Metabolomic analysis of experimental rodent malaria has provided significant insights into the mechanisms of disease progression including utilization of host resources by the parasite, sexual dimorphism in metabolic phenotypes, and cellular changes in host metabolism. Moreover, these studies also provide proof of concept for prediction of cerebral malaria. On the other hand, metabolite analysis of patient biofluids generates extensive data that could be of use in identifying biomarkers of infection severity and in monitoring disease progression. Through the use of metabolomic datasets one hopes to assess crucial infection-specific issues such as clinical severity, drug resistance, therapeutic targets, and biomarkers. Also discussed are nascent or newly emerging areas of metabolomics such as pre-erythrocytic stages of the infection and the host immune response. This review is organized in four broad sections—methodologies for metabolomic analysis, rodent infection models, studies of human clinical specimens, and potential of immunometabolomics. Data summarized in this review should serve as a springboard for novel hypothesis testing and lead to a better understanding of malarial infection and parasite biology.

Intra-laboratory Development and Evaluation of a Quantitative Method for Measurement of Aflatoxins B1, M1 and Q1 in Animal Urine by High Performance Liquid Chromatography with Fluorescence Detection.

Mycotoxins negatively impact animal health. Aflatoxins (AFs) are the most common mycotoxins affecting both large and small animals and are a common cause of toxin-related pet food recalls. Definitive diagnosis of aflatoxicosis is constrained by a lack of validated ante-mortem analytical methods for detection and quantitation of AFs and their metabolites in biological specimens. Herein, we developed and evaluated a urine-based quantitative method for measurement of aflatoxin B1 (AFB1) and its metabolites aflatoxin M1 (AFM1) and aflatoxin Q1 (AFQ1) in animal urine. (Some of the results have been presented at 59th AAVLD conference, Greensboro, North Carolina, October 13-19th, 2016.) This method uses an immuno-affinity column for clean-up and pre-column derivatization followed by high performance liquid chromatography analysis with fluorescence detection. The method has high selectivity, recovery (>81%) and sensitivity with an instrument limit of detection of 0.20-1.02 pg; instrument limit of quantitation of 0.77-4.46 pg; and a method lower limit of quantitation of 0.30-2.5 ng/mL. The method has high accuracy, repeatability, and is rugged against minor changes. However, because of poor sensitivity of AFQ1 at low concentrations we recommend this method for quantitative determination of AFB1 and AFM1, and for qualitative measurement of AFQ1 in animal urine for diagnosis of aflatoxicosis.

Identification of New Synthetic Cannabinoid ADB-CHMINACA (MAB-CHMINACA) Metabolites in Human Hepatocytes

ADB-CHMINACA (MAB-CHMINACA) is a new synthetic cannabinoid with high potency and many reported adverse events and fatalities. The drug is currently scheduled in several countries in Europe and the USA. Analytical methods need to be developed to confirm ADB-CHMINACA intake for clinical and forensic programs. For many synthetic cannabinoids, parent compound is not detectable in biological samples after intake, making the detection of metabolites the only way to prove consumption. Therefore, detection of ADB-CHMINACA metabolites in biological specimens is critical. Since there are currently no published data on ADB-CHMINACA metabolism, we aimed to identify its major metabolites. Cryopreserved human hepatocytes were incubated with 10 μmol/L ADB-CHMINACA for 3 h. Incubations were analyzed with liquid chromatography on a biphenyl column, high resolution tandem mass spectrometry (orbitrap), and metabolite identification software. A reference standard of six commercially available potential metabolites was simultaneously analyzed under the same conditions to allow correct assignment of isomers. We detected ten major metabolites. Biotransformations mainly occurred at the cyclohexylmethyl tail of the compound, as also observed with structural analogs’ metabolism. Minor reactions also occurred at the tert-butyl chain. Only two analytical standards of potential metabolites matched an actual metabolite detected in hepatocyte incubations. We recommend A9 (ADB-CHMINACA hydroxycyclohexylmethyl), A4 (ADB-CHMINACA 4″-hydroxycyclohexyl), and A6 (ADB-CHMINACA hydroxycyclohexylmethyl) as metabolite targets to document ADB-CHMINACA intake in clinical and forensic cases. Additionally, these results will guide analytical standard manufacturers to better provide suitable references for further studies on ADB-CHMINACA metabolism.

Distinguishing between the metabolome and xenobiotic exposome in environmental field samples analysed by direct-infusion mass spectrometry based metabolomics and lipidomics.

Environmental metabolomics is increasingly used to investigate organismal responses to complex chemical mixtures, including waste water effluent (WWE). In parallel, increasingly sensitive analytical methods are being used in metabolomics studies, particularly mass spectrometry. This introduces a considerable, yet overlooked, challenge that high analytical sensitivity will not only improve the detection of endogenous metabolites in biological specimens but also exogenous chemicals. If these often unknown xenobiotic features are not removed from the “biological” dataset, they will bias the interpretation and could lead to incorrect conclusions about the biotic response. Here we illustrate and validate a novel workflow classifying the origin of peaks detected in biological samples as: endogenous, xenobiotics, or metabolised xenobiotics. The workflow is demonstrated using direct infusion mass spectrometry-based metabolomic analysis of testes from roach exposed to different concentrations of a complex WWE. We show that xenobiotics and their metabolic products can be detected in roach testes (including triclosan, chloroxylenol and chlorophene), and that these compounds have a disproportionately high level of statistical significance within the total (bio)chemical changes induced by the WWE. Overall we have demonstrated that this workflow extracts more information from an environmental metabolomics study of complex mixture exposures than was possible previously.Electronic supplementary materialThe online version of this article (doi:10.1007/s11306-014-0693-3) contains supplementary material, which is available to authorized users.

Analysis of bisphenol A diglycidyl ether (BADGE) and its hydrolytic metabolites in biological specimens by high-performance liquid chromatography and tandem mass spectrometry.

Due to its cytotoxicity, genotoxicity, and adipogenicity observed in in vitro studies, bisphenol A diglycidyl ether (BADGE) may pose a health risk to humans. Quantifying BADGE exposure is an essential step to assess potential health risks associated with this ubiquitous compound widely used in certain plastic products. Due to the lack of endogenous sources for BADGE, bio-monitoring of BADGE and/or its hydrolytic metabolites (BADGE·H2O and BADGE·2H2O) can be a useful means to measure exposure. In this study, we developed a highly specific and sensitive method to measure BADGE, BADGE·H2O and BADGE·2H2O in plasma and urine, using a fast liquid-liquid extraction technique followed by a high-performance liquid chromatography and positive electrospray tandem mass spectrometry (LC-ESI-MS/MS) method. The method can quantify BADGE, BADGE·H2O and BADGE·2H2O with lower limits of quantification (LLOQ) of 0.05, 0.05 and 0.2 ng/ml, respectively. The percentage deviation of mean calculated concentrations from target concentrations was within 20%, variations across repeated analyses were within 15%, and mean extraction recovery was higher than 51.4% for all the three analytes in both plasma and urine matrices. The method has been applied to venous blood samples, cord blood samples, and urine samples collected from 9 to 14 adult volunteers. Results showed that concentrations of BADGE were lower than LLOQ in all of these samples except one urine sample. Low levels of BADGE·H2O from 0.108 to 0.222 ng/ml were observed in four venous blood samples and one urine sample (0.187 ng/ml). In contrast, concentrations of BADGE·2H2O were higher than LLOQ, varying from 0.660 to 303.593 ng/ml, in all the 10 venous blood samples and 1 cord blood sample (0.592 ng/ml) and two urine samples (0.200 and 0.306 ng/ml). The results suggest that bio-monitoring of blood and urine for BADGE exposure should focus on the hydrolysis derivatives of BADGE, mainly in the form of BADGE·2H2O.

Simultaneous determination of 18 abused opioids and metabolites in human hair using LC–MS/MS and illegal opioids abuse proven by hair analysis

Natural and synthetic opioids have efficient analgesic activity but can also be addictive. Thus, the determination of opioids and their metabolites in biological specimens is of interest in clinical and forensic toxicology laboratories. The analysis of drugs in hair provides valuable information on previous chronic drug use and has been successfully applied to the diagnosis of drug abuse, tolerance, compliance and gestational drug exposure. Despite the abuse of prescription opioids along with heroin and other illegal opiates, few studies have been conducted on the simultaneous determination of the broad range of opioids covering those drugs in hair. In the present study, an analytical method for the simultaneous detection in hair of 18 opioids and metabolites considered to have a high abuse risk based on the results of urine drug screening was established and validated using liquid chromatography–tandem mass spectrometry (LC–MS/MS) for the purpose of clinical and forensic applications. The drugs and metabolites were extracted from hair using methanol and analyzed using LC–MS/MS. The validation results proved that the method was selective, accurate and precise with acceptable linearity within calibration ranges. No significant variation was observed by different sources of matrices. The limits of detection and the limits of quantification ranged from 0.05 to 0.25ng/10mg hair and from 0.05 to 0.5ng/10mg hair, respectively. The developed method was successfully applied to 15 hair samples from opioids users. This method will be very useful for monitoring the inappropriate use of opioid drugs.

Quantitative analysis of propofol-glucuronide in hair as a marker for propofol abuse

The inappropriate or illegal use of propofol has recently come to the fore as a serious social issue in South Korea. Thus, in spite of its superior potency as a therapeutic drug, propofol was classified as a controlled drug under the purview of Narcotics Control Law in South Korea in February of 2011. Accordingly, the determination of propofol and/or its metabolites in biological specimens is required to prove ingestion. Therefore, to demonstrate chronic ingestion, a quantitative analytical method for propofol-glucuronide in hair was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). This method was applied to measure propofol-glucuronide in hair samples from 23 propofol abuse suspects and in both pigmented and nonpigmented hair from rats which had ingested propofol. Propofol-glucuronide in hair was extracted in methanol and then filtered and analyzed by LC-MS/MS with electrospray ionization in negative mode. The validation results of selectivity, matrix effect, recovery, linearity, precision and accuracy, and processed sample stability were satisfactory. The limit of detection was 20pg/10mg hair and the limit of quantification was 50pg/10mg hair. The concentration range of propofol-glucuronide in hair segments from 23 propofol abuse suspects was shown up to 1,410pg/mg. The animal study demonstrated that the presence of melanin did not affect the deposition of propofol-glucuronide in hair. Thus, we propose propofol-glucuronide in hair as a marker for propofol abuse. This method will be very useful for monitoring the inappropriate use of propofol for both legal and public health aspects.

Metabolomic Profiling for the Identification of Novel Biomarkers and Mechanisms Related to Common Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, but their molecular etiology remains poorly understood, in part because they develop slowly as a result of a mixture of genetic and environmental factors. Given the complex nature of CVD, molecular profiling of processes more “proximal” to the disease than genetic markers may have great promise in revealing both “form” (novel biomarkers with clinical potential) and “function” (mechanisms of disease development) of CVD. CVD is often associated with conditions of perturbed energy homeostasis and metabolism, including obesity, insulin resistance, and diabetes. The strong relationship between CVD and certain circulating lipids such as cholesterol and triglycerides has been recognized for decades. However, beyond these well-established associations, there is a strong possibility that other links between metabolic dysregulation and CVD remain to be discovered, and as a corollary, that new metabolite signatures can be identified that enhance risk prediction models. Comprehensive metabolic profiling, or “metabolomics” is increasingly being applied to CVD, leading to recent discoveries with both form and function implications. Here we review recent progress in this rapidly expanding area. Metabolomics is a term used to describe the measurement of multiple small-molecule metabolites in biological specimens, including bodily fluids (urine, blood, saliva), tissues, and breath exhalate. Metabolomics is perceived as a very recent addition to the omics platforms relative to genomics, transcriptomics, or proteomics, but in fact, its origins are in the venerable discipline of analytic biochemistry. Recent technological advances have enabled high-throughput profiling of large numbers of metabolites in biological samples, with increasing application to disease research, including CVD. One seemingly attractive feature of metabolic profiling is the relatively small number of human metabolites (≈7000) relative to the estimated numbers of genes (25 000), transcripts (100 000), and proteins (1 000 000). However, in reality, metabolites exist in a very …

How to use toxicology screening tests

The evaluation of poisoned patients presenting to the hospital predominantly relies on clinical assessment based on the history of ingestion/exposure and clinical symptoms/signs.1 The role of toxicological screening is controversial....

An ultrasonication-assisted extraction and derivatization protocol for GC/TOFMS-based metabolite profiling

Conventional chemical derivatization of metabolites in biological specimens is time-consuming, which limits the throughput and efficiency of metabolite profiling using a gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) platform. We report an ultrasonication-assisted protocol which reduces the derivatization time from hours to about 30 min and significantly enhances the derivatization efficiency prior to a GC/TOFMS analysis. The protocol was evaluated using 40 compounds representing different classes of human metabolites, and demonstrated good analytical precision and accuracy. In comparison with the conventional method, the new protocol was able to increase the intensity of most of the identified peaks (71.0%) in the GC/TOFMS chromatograms of human serum samples. The detected compounds with increased intensity include most amino acids, keto-containing organic acids, carbonyl-containing carbohydrates, and unsaturated fatty acids. We applied this protocol in a metabolomic study of human serum samples obtained from 34 patients diagnosed with hypertension and 29 age- and gender-matched healthy subjects. Metabolite markers associated with hypertension, including glucosamine, D-sorbitol, 1-stearoylglycerol, and homocysteine, were identified and validated by statistical methods and use of reference standards. Our work highlights the potential of this novel approach for the large-scale metabolite profiling of samples generated from plant, animal, and clinical and epidemiological studies.

Bioanalytical procedures and recent developments in the determination of opiates/opioids in human biological samples

The use and abuse of illegal drugs affects all modern societies, and therefore the assessment of drug exposure is an important task that needs to be accomplished. For this reason, the reliable determination of these drugs and their metabolites in biological specimens is an issue of utmost relevance for both clinical and forensic toxicology laboratories in their fields of expertise, including in utero drug exposure, driving under the influence of drugs and drug use in workplace scenarios. Most of the confirmatory analyses for abused drugs in biological samples are performed by gas chromatographic-mass spectrometric methods, but use of the more recent and sensitive liquid chromatography-(tandem) mass spectrometry technology is increasing dramatically. This article reviews recently published articles that describe procedures for the detection of opiates in the most commonly used human biological matrices, blood and urine, and also in unconventional ones, e.g. oral fluid, hair, and meconium. Special attention will be paid to sample preparation and chromatographic analysis.