GC-MS-based metabolomics of volatile organic compounds in exhaled breath: applications in health and disease. A review.

Exhaled breath analysis, with particular emphasis on volatile organic compounds, represents a growing area of clinical research due to its obvious advantages over other diagnostic tests. Numerous pathologies have been extensively investigated for the identification of specific biomarkers in exhalates through metabolomics. However, the transference of breath tests to clinics remains limited, mainly due to deficiency in methodological standardization.

Age-related tolerance to paraquat-induced parkinsonism in Drosophila melanogaster.

Paraquat (PQ) is a widely used herbicide that can cross the dopaminergic neuronal membrane, accumulate in mitochondria and damage complex I of the electron transport chain, leading to neuronal death. In Drosophila melanogaster, PQ exposure leads to the development of parkinsonism and is a classical model for studying Parkinson's Disease (PD). Muscle mitochondrial dysfunction, affecting survival and locomotion, is described in familial PD in D.

Antiinflammatory and antiinfective effect of caffeine in a mouse model of disseminated salmonellosis.

Caffeine has been reported for its antiinflammatory properties by stimulating phagocytosis. In this study, we investigated the antiinflammatory and antiinfective potential of caffeine in murine macrophage cell cultures and Swiss mice infected with virulent Salmonella enterica serotype typhimurium. Peritoneal macrophages (pMØ) were treated with caffeine on 96-well plates for 24 hr and then infected with Salmonella for 4 hr.

Detection of blood flow perfusion and post - occlusive reactive hyperemia in the skeletal muscle of rats.

Aims: Post-occlusive reactive hyperemia (PORH) remains poorly understood in the skeletal muscle system. This study was designed to validate an alternative strategy of PORH detection in rodents. Additionally, we explored the hypothesis that PORH is influenced by experimental models associated with impaired function of the skeletal muscle.

Application of in vivo solid phase microextraction (SPME) in capturing metabolome of apple (Malus ×domestica Borkh.) fruit.

An in vivo direct-immersion SPME sampling coupled to comprehensive two-dimensional gas chromatography - time-of-flight mass spectrometry (GCxGC-ToFMS) was employed to capture real-time changes in the metabolome of 'Honeycrisp' apples during ripening on the tree. This novel sampling approach was successful in acquiring a broad metabolic fingerprint, capturing unique metabolites and detecting changes in metabolic profiles associated with fruit maturation. Several metabolites and chemical classes, including volatile esters, phenylpropanoid metabolites, 1-octen-3-ol, hexanal, and (2E,4E)-2,4-hexadienal were found to be up-regulated in response to fruit maturation.

Crack cocaine smoke on pregnant rats: Maternal evaluation and teratogenic effect.

This study aimed to evaluate maternal toxicity, teratogenic, and placental oxidative effects resulting from the exposure of rats to crack cocaine smoke during pregnancy. Pregnant rats were exposed either to the smoke of crack and ashes (Crack) or to the smoke of ashes alone, nonexposed or pair-fed with the Crack group. Crack group was exposed to the smoke resulting from the burning of 250 mg of crack for 10 min, twice a day, from 7 days prior to mating until cesarian on gestational day 20.

Volatile profile and aroma potential of tropical Syrah wines elaborated in different maturation and maceration times using comprehensive two-dimensional gas chromatography and olfactometry.

The influence of different combinations of Syrah grape maturation degree (19, 21 and 23 °Brix) and maceration times (10, 20 and 30 days) on the volatile profile and aroma potential was evaluated for the first time through different chromatographic platforms (GC × GC/TOFMS, GC-O-OSME, GC-FID and GC/MS). GC × GC/TOFMS analyses resulted in 145 identified compounds and among these 29 were determined to be the most important for wine differentiation. The aroma compounds allowed the discrimination of Syrah wines made with grapes macerated for a shorter time (ten days) due to the higher levels of volatile compounds.

Carbonyl compounds and furan derivatives with toxic potential evaluated in the brewing stages of craft beer.

Carbonyl compounds and furan derivatives may form adducts with DNA and cause oxidative stress to human cells, which establishes the carcinogenic potential of these compounds. The occurrence of these compounds may vary according to the processing characteristics of the beer. The objective of this study was, for the first time, to investigate the free forms of target carbonyl compounds [acetaldehyde, acrolein, ethyl carbamate (EC) and formaldehyde] and furan derivatives [furfural and furfuryl alcohol (FA)] during the brewing stages of ale and lager craft beers.

Validation of an analytical method using HS-SPME-GC/MS-SIM to assess the exposure risk to carbonyl compounds and furan derivatives through beer consumption.

Compounds with toxic potential may occur in beer, such as carbonyl compounds (acetaldehyde, acrolein, ethyl carbamate [EC] and formaldehyde) and furan derivatives [furfural and furfuryl alcohol (FA)]. The objective of this study was, for the first time, to validate a method based on headspace-solid phase microextraction using a PDMS-overcoated fibre and gas chromatography with mass spectrometric detection in selected ion monitoring mode (HS-SPME-GC/MS-SIM) to investigate target carbonyl compounds and furan derivatives in beers. Analytical curves showed proper linearity with r ranging from 0.

Matrix-compatible solid phase microextraction coating improves quantitative analysis of volatile profile throughout brewing stages.

Ethanol is the major matrix constituent of beer and has been reported as an important interfering volatile during headspace solid phase microextraction (HS-SPME) of minor compounds due to its displacement effect. The addition of a thin hydrophobic polydimethylsiloxane (PDMS) layer on a commercial divinylbenzene/Carboxen/PDMS (DVB/Car/PDMS) fiber was evaluated, for the first time, to minimize the displacement effect caused by ethanol in the quantitative determination of volatile profile of five stages of brewing. Analysis were performed through gas chromatography coupled to mass spectrometry detector.

Structural and Chemical Profiles of (Myrtaceae) Leaves Under the Influence of the Galling sp. (Thysanoptera).

Thysanoptera-induced galls commonly culminate in simple folding or rolling leaf gall morphotypes. Most of these galls are induced by members of the suborder Tubulifera, with only a few species of the suborder Terebrantia being reported as gall inducers. The Terebrantia, as most of the gall inducers, manipulates the host plant cellular communication system, and induces anatomical and biochemical changes in its host plant.

Carbonyl compounds in different stages of vinification and exposure risk assessment through Merlot wine consumption.

The objective of this research was to estimate for the first time the transformations that the free form of some target carbonyl compounds may undergo during winemaking and assess the exposure risk to these compounds through the consumption of the Merlot commercial wines under study. Acrolein and furfural were found in grapes and the respective wines, although levels were observed to decline throughout the winemaking process. Formaldehyde was found in all stages of wine production in levels lower than the limit of quantification of the method and ethyl carbamate was not found in samples.

Exploiting the tunable selectivity features of polymeric ionic liquid-based SPME sorbents in food analysis.

In this work, the performances of polymeric ionic liquid (PIL) based solid-phase microextraction (SPME) coatings were assessed for applications concerning food safety and quality. Two different polymeric ionic liquid coatings, namely poly(1-4-vinylbenzyl-3-hexadecylimidazolium) bis[(trifluoromethyl)sulfonyl] imide (poly([VBHDIM][NTf2]), PIL 1, and N,N-didecyl-N-methyl-d-glucaminium poly(2-methyl-acrylic acid 2-[1-(3-{2-[2-(3-trifluoromethanesulfonylamino-propoxy)-ethoxy]-ethoxy}-propylamino)-vinylamino]-ethyl ester) (poly([DDMGlu][MTFSI]), PIL 2, were evaluated. The PIL-based coatings were compared to commercially available SPME coatings in terms of their performance toward extraction of pesticides and fruit metabolites.

Sensory, olfactometry and comprehensive two-dimensional gas chromatography analyses as appropriate tools to characterize the effects of vine management on wine aroma.

For the first time, the influence of different vine management was evaluated in relation to volatile profile and sensory perception through GC×GC/TOFMS, QDA, GC-FID, GC/MS, and GC-O. GC×GC/TOFMS analyses and QDA have shown that a larger spacing between vine rows (2 rather than 1m), attachment of shoots upwards, and irrigation did not result in wine improvement. Conversely, wines elaborated with grapes from a vine with a lower bud load (20 per plant; sample M1) stood out among the other procedures, rendering the most promising wine aroma.

Development of a HS-SPME-GC/MS protocol assisted by chemometric tools to study herbivore-induced volatiles in Myrcia splendens.

A headspace solid phase microextraction (HS-SPME) method combined with gas chromatography-mass spectrometry (GC/MS) was developed and optimized for extraction and analysis of volatile organic compounds (VOC) of leaves and galls of Myrcia splendens. Through a process of optimization of main factors affecting HS-SPME efficiency, the coating divivnilbenzene-carboxen-polydimethylsiloxane (DVB/Car/PDMS) was chosen as the optimum extraction phase, not only in terms of extraction efficiency, but also for its broader analyte coverage. Optimum extraction temperature was 30°C, while an extraction time of 15min provided the best compromise between extraction efficiencies of lower and higher molecular weight compounds.

Blood flow after contraction and cuff occlusion is reduced in subjects with muscle soreness after eccentric exercise.

Delayed onset muscle soreness (DOMS) occurs within 1-2 days after eccentric exercise, but the mechanism mediating hypersensitivity is unclear. This study hypothesized that eccentric exercise reduces the blood flow response following muscle contractions and cuff occlusion, which may result in accumulated algesic substances being a part of the sensitization in DOMS. Twelve healthy subjects (five women) performed dorsiflexion exercise (five sets of 10 repeated eccentric contractions) in one leg, while the contralateral leg was the control.

Insights into the Effect of the PDMS-Layer on the Kinetics and Thermodynamics of Analyte Sorption onto the Matrix-Compatible Solid Phase Microextraction Coating.

The currently presented research investigated the performance of matrix compatible PDMS-overcoated fibers (PDMS-DVB/PDMS) as compared to unmodified PDMS/DVB coatings using aqueous samples and employing a wide range of analyte polarities, molecular weights, and functionalities. In the first part of the work, a kinetic approach was taken to investigate the effect of the PDMS outer layer on the uptake rate of analytes during the mass transfer process. In short, the results can be simplified into two models: (1) the rate-limiting step is the diffusion through the coating and (2) the rate-limiting step is the diffusion through the aqueous diffusional boundary layer.

Characterization of sulfur and nitrogen compounds in Brazilian petroleum derivatives using ionic liquid capillary columns in comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection.

Diesel and naphtha samples were analyzed using ionic liquid (IL) columns to evaluate the best column set for the investigation of organic sulfur compounds (OSC) and nitrogen(N)-containing compounds analyses with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry detector (GC×GC/TOFMS). Employing a series of stationary phase sets, namely DB-5MS/DB-17, DB-17/DB-5MS, DB-5MS/IL-59, and IL-59/DB-5MS, the following parameters were systematically evaluated: number of tentatively identified OSC, 2D chromatographic space occupation, number of polyaromatic hydrocarbons (PAH) and OSC co-elutions, and percentage of asymmetric peaks. DB-5MS/IL-59 was chosen for OSC analysis, while IL59/DB-5MS was chosen for nitrogen compounds, as each stationary phase set provided the best chromatographic efficiency for these two classes of compounds, respectively.

Histaminergic Pharmacology Modulates the Analgesic and Antiedematogenic Effects of Spinally Injected Morphine.

Background: Histamine receptors are known to participate in spinal cord nociceptive transmission, and previous studies have suggested that histaminergic receptors are involved in the analgesic effects of morphine. Herein, we investigated the effect of intrathecal injection of histaminergic agonists and antagonists in a model of acute articular inflammation and their interaction with morphine.

Methods: After carrageenan injection in the right knee joint, articular incapacitation was measured hourly, for up to 6 hours, by the paw elevation time during 1-minute periods of stimulated walking.

Methodical evaluation and improvement of matrix compatible PDMS-overcoated coating for direct immersion solid phase microextraction gas chromatography (DI-SPME-GC)-based applications.

The main quest for the implementation of direct SPME to complex matrices has been the development of matrix compatible coatings that provide sufficient sensitivity towards the target analytes. In this context, we present here a thorough evaluation of PDMS-overcoated fibers suitable for simultaneous extraction of different polarities analytes, while maintaining adequate matrix compatibility. For this, eleven analytes were selected, from various application classes (pesticides, industrial chemicals and pharmaceuticals) and with a wide range of log P values (ranging from 1.

Capturing Plant Metabolome with Direct-Immersion in Vivo Solid Phase Microextraction of Plant Tissues.

For the first time, an in vivo sampling mode of direct immersion-solid phase microextraction (DI-SPME) was employed to capture the metabolome of living plant specimens, using apple (Malus × domestica Borkh.) as a model system. Metabolites were extracted from apple tissues and introduced by thermal desorption into a comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry instrument.

Headspace versus direct immersion solid phase microextraction in complex matrixes: investigation of analyte behavior in multicomponent mixtures.

This work aims to investigate the behavior of analytes in complex mixtures and matrixes with the use of solid-phase microextraction (SPME). Various factors that influence analyte uptake such as coating chemistry, extraction mode, the physicochemical properties of analytes, and matrix complexity were considered. At first, an aqueous system containing analytes bearing different hydrophobicities, molecular weights, and chemical functionalities was investigated by using commercially available liquid and solid porous coatings.

Sample preparation with solid phase microextraction and exhaustive extraction approaches: Comparison for challenging cases.

In chemical analysis, sample preparation is frequently considered the bottleneck of the entire analytical method. The success of the final method strongly depends on understanding the entire process of analysis of a particular type of analyte in a sample, namely: the physicochemical properties of the analytes (solubility, volatility, polarity etc.), the environmental conditions, and the matrix components of the sample.