190 research outputs found

    Blood and Plasma Volumetric Absorptive Microsampling (VAMS) Coupled to LC-MS/MS for the Forensic Assessment of Cocaine Consumption

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    Reliable, feasible analytical methods are needed for forensic and anti-doping testing of cocaine and its most important metabolites, benzoylecgonine, ecgonine methyl ester, and cocaethylene (the active metabolite formed in the presence of ethanol). An innovative workflow is presented here, using minute amounts of dried blood or plasma obtained by volumetric absorptive microsampling (VAMS), followed by miniaturized pretreatment by dispersive pipette extraction (DPX) and LC-MS/MS analysis. After sampling 20 \ub5L of blood or plasma with a VAMS device, the sample was dried, extracted, and loaded onto a DPX tip. The DPX pretreatment lasted less than one minute and after elution with methanol the sample was directly injected into the LC-MS/MS system. The chromatographic analysis was carried out on a C8 column, using a mobile phase containing aqueous formic acid and acetonitrile. Good extraction yield (> 85%), precision (relative standard deviation, RSD < 6.0%) and matrix effect (< 12%) values were obtained. Analyte stability was outstanding (recovery > 85% after 2 months at room temperature). The method was successfully applied to real blood and plasma VAMS, with results in very good agreement with those of fluid samples. The method seems suitable for the monitoring of concomitant cocaine and ethanol use by means of plasma or blood VAMS testing

    Green analytical chemistry (GAC) applications in sample preparation for the analysis of anthocyanins in products and by-products from plant sources

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    Agri-food industry manufacturing is an important source of environmental pollution and eutrophication, both intrinsically and due to the generation of significant amount of by-products. For this reason, green chemistry is currently at the forefront of efforts to make all steps of agri-food workflows more sustainable and environmentally friendly and to reduce their carbon footprint. Green analytical chemistry (GAC) is an integral part of these efforts, although it has been largely neglected until now, due to the fact that analytical procedures are mainly limited to quality control in this field, and thus produce just a small fraction of the overall environmental burden of agri-food processes. In this mini-review, the most recent developments of green analytical methods are described, relative to their applications for anthocyanin determination in agri-food products and by-products. Anthocyanins have been chosen as they are among the most valuable secondary plant metabolites, with a wide range of possible applications exploiting their preservative, antioxidant and coloring properties. Non-separative and separative analytical meth- ods are included in this mini-review. The former are mainly spectrometric in nature, and usually mostly allow to detect and/or quantify groups or classes of molecules. However, they also provide very high throughput and the greatest chance to develop low-energy, low-solvent consumption procedures, even to the point of enabling direct determinations in solid samples as such. On the other hand, separative methods provide far greater selectivity and far wider applicability, but at the price of higher energy and resource consumption and usually lower throughput

    An Original HPLC Method with Coulometric Detection to Monitor Hydroxyl Radical Generation via Fenton Chemistry

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    Hydroxyl radicals (•OH) can be generated via Fenton chemistry catalyzed by transition metals. An in vitro Fenton system was developed to test both the inhibition and stimulation of •OH formation, by monitoring salicylate aromatic hydroxylation derivatives as markers of •OH production. The reaction was optimized with either iron or copper, and target analytes were determined by means of an original HPLC method coupled to coulometric detection. The method granted good sensitivity and precision, while method applicability was tested on antioxidant compounds with and without chelating properties in different substance to metal ratios. This analytical approach shows how Fenton's reaction can be monitored by HPLC coupled to coulometric detection, as a powerful tool for studying molecules' redox behavior

    Enantioselective analysis of the methamphetamine precursors ephedrine and pseudoephedrine by capillary electrokinetic chromatography using cyclodextrins as chiral selectors

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    Ephedrine and pseudoephedrine can be used as precursors for the illicit synthesis of stimulant drugs, such as methamphetamine and methcathinone. For this reason, an enantioselective capillary electrokinetic chromatography method was developed for the separation of ephedrine and pseudoephedrine enantiomers. After testing two different charged or chargeable cyclodextrins (β-cyclodextrin sulphate and carboxymethyl-β-cyclodextrin) and a few mixtures as possible chiral selectors, a mixture of 3 mM carboxymethyl-β-cyclodextrin and 3 mM heptakis(2,6-di-O-methyl)-β-cyclodextrin in pH 3.4 acetate buffer was used as the enantioselective background electrolyte and the separation was carried out in an uncoated silica capillary (75 µm internal diameter, 48.6 cm total length, 40.0 cm effective length). Analytical method performance was then evaluated in terms of linearity, precision, selectivity and accuracy with good results. Proof of concept application to mixtures simulating illicit methamphetamine (containing small amounts of ephedrine and pseudoephedrine as possible residual synthesis impurities) provided satisfactory results for the identification and quantitation of the four analyte diastereomers

    Dried Volumetric Microsampling Approaches for the Therapeutic Drug Monitoring of Psychiatric Patients Undergoing Clozapine Treatment

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    Clozapine is one of the most widely used second-generation antipsychotic drugs (SGAs) for the treatment of schizophrenia. Despite advantages over first-generation drugs, clozapine still shows significant side effects and interindividual variations in efficacy. In order to ensure frequent therapeutic drug monitoring (TDM) and improve the compliance of psychiatric patients undergoing clozapine treatment, two novel dried microsampling approaches based on whole blood and plasma volumetric absorptive microsampling (b-VAMS and p-VAMS) and microfluidic generated-dried blood spot technology (mfDBS) were developed and coupled to HPLC with electrochemical detection (ED). The proposed miniaturized strategies by means of VAMS and microfluidic channel-based devices provide several advantages in terms of collection, storage, and handling compared to classical blood and plasma processing. Satisfactory validation results were obtained for all microsampling platforms, with mean extraction yields >85.1%, precision as relative standard deviation (RSD) < 5.1%, and stability < 4.5% analyte loss after 30 days for p-VAMS; mean extraction yields > 83.4%, precision RSD < 5.4%, and stability < 4.6% analyte loss after 30 days for b-VAMS, and mean extraction yields > 74.0%, precision RSD < 5.6%, and stability < 4.9% analyte loss after 30 days for mfDBS. The original microsampling methodologies have been successfully applied to the blood and plasma collected from five psychiatric patients for the monitoring of the levels of clozapine and its main metabolites, providing robust and reliable quali-quantitative results. Comparisons between results of the two dried microsampling technologies with those obtained by classic fluid plasma analysis were in good agreement and have demonstrated that the proposed miniaturized approaches could be suitable for TDM purposes

    Clinopodium tomentosum (Kunth) Govaerts Leaf Extract Influences in vitro Cell Proliferation and Angiogenesis on Primary Cultures of Porcine Aortic Endothelial Cells

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    Clinopodium tomentosum (Kunth) Govaerts is an endemic species in Ecuador, where it is used as an anti-inflammatory plant to treat respiratory and digestive affections. In this work, effects of a Clinopodium tomentosum ethanolic extract (CTEE), prepared from aerial parts of the plant, were investigated on vascular endothelium functions. In particularly, angiogenesis activity was evaluated, using primary cultures of porcine aortic endothelial cells (pAECs). Cells were cultured for 24 h in the presence of CTEE different concentrations (10, 25, 50, and 100 \u3bcg/ml); no viability alterations were found in the 10-50 \u3bcg/ml range, while a slight, but significant, proliferative effect was observed at the highest dose. In addition, treatment with CTEE was able to rescue LPS-induced injury in terms of cell viability. The CTEE ability to affect angiogenesis was evaluated by scratch test analysis and by an in vitro capillary-like network assay. Treatment with 25-50\u3bcg/ml of extract caused a significant increase in pAEC\u2019s migration and tube formation capabilities compared to untreated cells, as results from the increased master junctions\u2019 number. On the other hand, CTEE at 100 \u3bcg/ml did not induce the same effects. Quantitative PCR data demonstrated that FLK-1 mRNA expression significantly increased at a CTEE dose of 25\u3bcg/ml. The CTEE phytochemical composition was assessed through HPLC-DAD; rosmarinic acid among phenolic acids and hesperidin among flavonoids were found as major phenolic components. Total phenolic content and total flavonoid content assays showed that flavonoids are the most abundant class of polyphenols. The CTEE antioxidant activity was also showed by means of the DPPH and ORAC assays. Results indicate that CTEE possesses an angiogenic capacity in a dose-dependent manner; this represents an initial step in elucidating the mechanism of the therapeutic use of the plant

    Degenerative Myelopathy in Hovawart Dogs: Molecular Characterization, Pathological Features and Accumulation of Mutant Superoxide Dismutase 1 Protein

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    Degenerative myelopathy (DM) is an adult-onset, progressive neurological disease affecting several breeds of dog. Homozygosity or compound heterozygosity for the canine superoxide dismutase 1 (SOD1) gene mutations, possibly modulated by the modifier SP110 locus, are associated with a high risk for DM. Although the pathophysiological mechanisms are largely unknown, a role for mutant SOD1 in causing neuronal degeneration has been postulated. Three Hovawart dogs, 9e12 years of age, developed slowly progressive incoordination and weakness of the pelvic limbs leading to non-ambulatory flaccid paraparesis and muscle atrophy. Neuropathological lesions comprised axonal degeneration and loss of ascending and descending spinal pathways, which were most severe in the mid- to caudal thoracic segments. Accumulation of mutant SOD1 protein in neurons and reactive astrocytes was demonstrated by immunolabelling with the 16G9 antibody against the mutant SOD1 protein (p.E40K amino acid substitution). All three dogs were homozygous for the c.118A allele, but none had the SP110 ‘risk’ haplotype, suggesting a weak association of SP110 with the onset of DM in this breed. Our data suggest that the Hovawart breed is predisposed to the SOD1:c.118G>A mutation, which is associated with the development of DM. Prevention of DM could be achieved with the help of strategies based on epidemiological and genetic testing

    Serial Ultrasound Assessment of Diaphragmatic Function and Clinical Outcome in Patients with Amyotrophic Lateral Sclerosis.

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    Background: Ultrasound (US) evaluation of the diaphragm may be a non-volitional useful tool in the clinical management of patients with ALS. Aim of the present study was then to evaluate the impact of serial assessment of ΔTmax index on clinical outcomes during the follow-up in these patients and to correlate non-volitional US indices and other volitional measures with these outcomes. Methods: A cohort of 39 consecutive patients with ALS was followed up to 24 months. At baseline and every 3-month spirometry (forced vital capacity-FVC), sniff inspiratory nasal pressure (SNIP), and US of the diaphragm (ΔTdi and ΔTmax) were recorded. These parameters were correlated with clinical outcomes (hypercapnia, nocturnal hypoventilation, NIV start in the following 6 month, and death within 1 year). Results: The occurrence of ΔTmax >0.75 during follow-up increased the risk for NIV (HR=5.6, p=0.001) and death (HR=3.7, p=0.0001) compared with patients with stable lower values. The evidence of diaphragmatic dysfunction, i.e. ΔTmax >0.75, occurs 3.2 month earlier than the onset of NIV. Moreover, ΔTmax >0.75 correlated with onset of nocturnal hypoventilation, NIV initiation within 6 months, and death within 12 months, similarly to FVC <50% predicted and better than other functional indices. Conclusions: Serial monitoring of diaphragmatic ΔTmax by US may be useful to predict initiation of NIV and death in patients with ALS. The occurrence of an abnormal ΔTmax value in the follow-up precedes the decision for starting NIV

    Non-neural phenotype of spinal and bulbar muscular atrophy: Results from a large cohort of Italian patients

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    Objective: To carry out a deep characterisation of the main androgen-responsive tissues involved in spinal and bulbar muscular atrophy (SBMA). Methods: 73 consecutive Italian patients underwent a full clinical protocol including biochemical and hormonal analyses, genitourinary examination, bone metabolism and densitometry, cardiological evaluation and muscle pathology. Results: Creatine kinase levels were slightly to markedly elevated in almost all cases (68 of the 73; 94%). 30 (41%) patients had fasting glucose above the reference limit, and many patients had total cholesterol (40; 54.7%), low-density lipoproteins cholesterol (29; 39.7%) and triglyceride (35; 48%) levels above the recommended values. Although testosterone, luteinising hormone and follicle-stimulating hormone values were generally normal, in one-third of cases we calculated an increased Androgen Sensitivity Index reflecting the presence of androgen resistance in these patients. According to the International Prostate Symptom Score (IPSS), 7/70 (10%) patients reported severe lower urinal tract symptoms (IPSS score >19), and 21/73 (30%) patients were moderately symptomatic (IPSS score from 8 to 19). In addition, 3 patients were carriers of an indwelling bladder catheter. Videourodynamic evaluation indicated that 4 of the 7 patients reporting severe urinary symptoms had an overt prostate-unrelated bladder outlet obstruction. Dual-energy X-ray absorptiometry scan data were consistent with low bone mass in 25/61 (41%) patients. Low bone mass was more frequent at the femoral than at the lumbar level. Skeletal muscle biopsy was carried out in 20 patients and myogenic changes in addition to the neurogenic atrophy were mostly observed. Conclusions: Our study provides evidence of a wide non-neural clinical phenotype in SBMA, suggesting the need for comprehensive multidisciplinary protocols for these patients. \ua9 2016 Published by the BMJ Publishing Group Limited
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