40 research outputs found

    High-resolution mass spectrometry for integrated qualitative and quantitative analysis of pharmaceuticals in biological matrices

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    Quantitative and qualitative high-resolution (HR) dependent and independent acquisition schemes on a QqTOF MS (with resolving power 20,000-40,000) were investigated for the analysis of pharmaceutical compounds in biological fluids. High-resolution selected reaction monitoring (HR-SRM) was found to be linear over three orders of magnitude for quantitative analysis of paracetamol in human plasma, offering a real alternative to triple quadrupole LC-SRM/MS. Metabolic stability of talinolol in microsomes was characterized by use of three different acquisition schemes: (i) information-dependent acquisition (IDA) with a TOF MS experiment as survey scan and product-ion scan as dependent scan; (ii) MSALL by collecting TOF mass spectra with and without fragmentation by alternating the collision energy of the collision cell between a low (i.e., 10eV) and high setting (i.e., 40eV); and (iii) a novel independent acquisition mode referred to as "sequential window acquisition of all theoretical fragment-ion spectra” (SWATH) or "global precursor ions scan mode” (GPS) in which sequential precursor ions windows (typically 20 u) are used to collect the same spectrum precursor and fragment ions using a collision energy range. SWATH or GPS was found to be superior to IDA or MSALL in combination with UHPLC for qualitative analysis but requires a rapidly acquiring mass spectrometer. Finally, the GPS concept was used for QUAL/QUAN analysis (i.e. integration of qualitative and quantitative analysis) of bosentan and its metabolites in urine over a concentration range from 5 to 2,500ngmL−

    Mass Spectrometric QUAL/QUAN Approaches for Drug Metabolism and Metabolomics

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    A liquid chromatography–high-resolution mass spectrometry platform was used for simultaneous qualitative and quantitative (QUAL/QUAN) acquisition, enabling drug metabolism and metabolomics investi- gations. Plasma study samples were monitored for three different groups of patients at a single time-point (1 h after drug administration): one group received acetaminophen (APAP), one group received both APAP and ketorolac and one group was a control group. The quantification of APAP and two of its metabolites (APAP-glucuronide and APAP-cysteine) was performed on a fast acquisition quadrupole-Time-Of-Flight (50–100 ms duty cycle, resolving power of 30,000) compatible with UHPLC time constraints. High-resolution Selected Reaction Monitoring was used for quantification of APAP and its metabolites from 50–10,000 ng/mL using a 50 ?L plasma aliquot. Average measured concentrations were for APAP 6,650 ng/mL vs 6,160 ng/mL, APAP-CYS concentrations were 154.2 ng/mL vs 140.6 ng/mL and APAP-GLU concentrations 8,750 ng/mL vs 8,430 ng/mL between the group that received only APAP (n = 11) and the group that received APAP in combination with ketorolac (n = 11). No major differences were observed between the two groups of patients, as it would be expected due to the differing metabolism pathway for both substances. For the qualitative aspect, a metabolomics data processing platform with biological QC samples was applied to the study samples to search for unanticipated metabolites and biomarkers related to APAP and ketorolac metabolism. Multivariate analysis (i.e. Principle Component Analysis), variables grouping tools (i.e. PCVG) and high-resolution MS(/MS) spectra from the MSALL acquisition strategy enabled the profiling and characterization of circulating metabolites of APAP in plasma such as APAP-sulfate, APAP-mercapturate as well as ketorolac

    Small extracellular vesicles released from germinated kiwi pollen (pollensomes) present characteristics similar to mammalian exosomes and carry a plant homolog of ALIX

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    Introduction: In the last decade, it has been discovered that allergen-bearing extracellular nanovesicles, termed “pollensomes”, are released by pollen during germination. These extracellular vesicles (EVs) may play an important role in pollen-pistil interaction during fertilization, stabilizing the secreted bioactive molecules and allowing long-distance signaling. However, the molecular composition and the biological role of these EVs are still unclear. The present study had two main aims: (I) to clarify whether pollen germination is needed to release pollensomes, or if they can be secreted also in high humidity conditions; and (II) to investigate the molecular features of pollensomes following the most recent guidelines for EVs isolation and identification. Methods: To do so, pollensomes were isolated from hydrated and germinated kiwi (Actinidia chinensis Planch.) pollen, and characterized using imaging techniques, immunoblotting, and proteomics. Results: These analyses revealed that only germinated kiwi pollen released detectable concentrations of nanoparticles compatible with small EVs for shape and protein content. Moreover, a plant homolog of ALIX, which is a well-recognized and accepted marker of small EVs and exosomes in mammals, was found in pollensomes. Discussion: The presence of this protein, along with other proteins involved in endocytosis, is consistent with the hypothesis that pollensomes could comprehend a prominent subpopulation of plant exosome-like vesicles

    Small extracellular vesicles released from germinated kiwi pollen (pollensomes) present characteristics similar to mammalian exosomes and carry a plant homolog of ALIX

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    IntroductionIn the last decade, it has been discovered that allergen-bearing extracellular nanovesicles, termed “pollensomes”, are released by pollen during germination. These extracellular vesicles (EVs) may play an important role in pollen-pistil interaction during fertilization, stabilizing the secreted bioactive molecules and allowing long-distance signaling. However, the molecular composition and the biological role of these EVs are still unclear. The present study had two main aims: (I) to clarify whether pollen germination is needed to release pollensomes, or if they can be secreted also in high humidity conditions; and (II) to investigate the molecular features of pollensomes following the most recent guidelines for EVs isolation and identification.MethodsTo do so, pollensomes were isolated from hydrated and germinated kiwi (Actinidia chinensis Planch.) pollen, and characterized using imaging techniques, immunoblotting, and proteomics.ResultsThese analyses revealed that only germinated kiwi pollen released detectable concentrations of nanoparticles compatible with small EVs for shape and protein content. Moreover, a plant homolog of ALIX, which is a well-recognized and accepted marker of small EVs and exosomes in mammals, was found in pollensomes.DiscussionThe presence of this protein, along with other proteins involved in endocytosis, is consistent with the hypothesis that pollensomes could comprehend a prominent subpopulation of plant exosome-like vesicles

    Bamboo reinforced concrete: a critical review

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    © 2018, The Author(s). The use of small diameter whole-culm (bars) and/or split bamboo (a.k.a. splints or round strips) has often been proposed as an alternative to relatively expensive reinforcing steel in reinforced concrete. The motivation for such replacement is typically cost—bamboo is readily available in many tropical and sub-tropical locations, whereas steel reinforcement is relatively more expensive—and more recently, the drive to find more sustainable alternatives in the construction industry. This review addresses such ‘bamboo-reinforced concrete’ and assesses its structural and environmental performance as an alternative to steel reinforced concrete. A prototype three bay portal frame, that would not be uncommon in regions of the world where bamboo-reinforced concrete may be considered, is used to illustrate bamboo reinforced concrete design and as a basis for a life cycle assessment of the same. The authors conclude that, although bamboo is a material with extraordinary mechanical properties, its use in bamboo-reinforced concrete is an ill-considered concept, having significant durability, strength and stiffness issues, and does not meet the environmentally friendly credentials often attributed to it

    Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

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    Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

    Qualitative and quantitative determination of drugs, metabolites and their adducts to proteins in biological matrices by liquid chromatography hyphenated to low and high resolution mass spectrometry

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    The development of targeted and untargeted analytical methods to support metabolomics studies has generated a paradigm shift in bioanalysis. In particular, liquid chromatography hyphenated to mass spectrometry has demonstrated the capability to quantify and identify thousands of compounds in biological samples using different instruments. Until recently, low and high resolution mass spectrometers were concomitantly used to achieve these goals. The recent development of fast-acquiring and sensitive high resolution mass spectrometers has opened the door to efficient and simultaneous qualitative and quantitative data acquisition. The central theme of this thesis was the investigation of these novel tools applied to drug metabolism and toxicology. The study of the metabolism of fipexide, a nootropic hepatotoxic drug, is described. The quantitative determination of acetaminophen (paracetamol) and its metabolites along with the measure of its adducts to proteins combined with untargeted analysis is also presented within the frame of a clinical study with overdosed patients

    Removal of batch effects using stratified subsampling of metabolomic data for in vitro endocrine disruptors screening

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    The human adrenal cell line H295R constitutes a well-established model to evaluate potential alterations of steroidogenic pathways as a result of chemical exposure. However, to date most assays are based on the targeted investigation of a limited number of steroid hormones, thus preventing in-depth mechanistic interpretation with respect to steroidogenesis. In that context, analytical strategies coupling liquid chromatography and high-resolution mass spectrometry (LC-HRMS) have been reported as promising methods for an extended monitoring of steroid metabolites. However, unwanted sources of variability occurring during the acquisition process, including batch effects, may prevent relevant biochemical information to be properly highlighted. Dedicated data mining strategies are therefore needed to overcome these limitations, and extract relevant extended steroidomic profiles. The present study combines an untargeted LC-HRMS acquisition strategy with automated steroid metabolite annotation based on accurate mass and isotopic patterns, and a chemometric tool allowing the different sources of variability to be decomposed based on experimental design. This workflow was applied to the extended monitoring of steroidogenic dysregulations due to endocrine disrupting chemicals (EDCs) exposure in H295R cell cultures. A series of six chemicals, including acetyl tributylcitrate, octyl methoxycinnamate, torcetrapib, forskolin, linuron, and octocrylene, and dimethylsulfoxide as solvent control, were investigated through the simultaneous monitoring of 130 potential steroid metabolites, repeating the whole experiment independently three times. A stratified subsampling strategy was carried out to remove efficiently systematic batch variations and highlight subgroups of chemicals with similar steroid patterns. The proposed approach was reported as a potent screening strategy, as it allowed specific alterations of the steroid hormone biosynthesis and metabolism related to distinct mechanisms of action to be distinguished

    Modelling and validation of electromechanical shock absorbers

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    Electromechanical vehicle suspension systems represent a promising substitute to conventional hydraulic solutions. However, the design of electromechanical devices that are able to supply high damping forces without exceeding geometric dimension and mass constraints is a difficult task. All these challenges meet in off-road vehicle suspension systems, where the power density of the dampers is a crucial parameter. In this context, the present paper outlines a particular shock absorber configuration where a suitable electric machine and a transmission mechanism are utilised to meet off-road vehicle requirements. A dynamic model is used to represent the device. Subsequently, experimental tests are performed on an actual prototype to verify the functionality of the damper and validate the proposed mode
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