Fragmentation pathways of drugs of abuse and their metabolites based on QTOF MS/MS and MSE accurate-mass spectra

A study of the fragmentation pathways of several classes of drugs of abuse (cannabinoids, ketamine, amphetamine and amphetamine-type stimulants (ATS), cocaine and opiates) and their related substances has been made. The knowledge of the fragmentation is highly useful for specific fragment selection or for recognition of related compounds when developing MS-based analytical methods for the trace-level determination of these compounds in complex matrices. In this work, accurate-mass spectra of selected compounds were obtained using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry, performing both MS/MS and MSE experiments. As regards fragmentation behavior, the mass spectra of both approaches were quite similar and were useful to study the fragmentation of the drugs investigated. Accurate-mass spectra of 37 drugs of abuse and related compounds, including metabolites and deuterated analogues, were studied in this work, and structures of fragment ions were proposed. The accurate-mass data obtained allowed to confirm structures and fragmentation pathways previously proposed based on nominal mass measurements, although new insights and structure proposals were achieved in some particular cases, especially for amphetamine and ATS, 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) and opiates.This work has been developed under financial support provided by the Spanish Ministry of Education and Science (project reference: CTQ2009-12347) and the Generalitat Valenciana, as research group of excellence PROMETEO/2009/05

Role of UEV-1A, a homologue of the tumor suppressor protein TSG101, in protection from DNA damage

AbstractThe open reading frame YGL087c in the budding yeast Saccharomyces cerevisiae genome encodes a polypeptide highly similar to the human UEV (ubiquitin-conjugating E2 enzyme variant) proteins, which have been proposed to belong to a family of putative dominant negative ubiquitin regulators. Deletion of the YGL087c open reading frame yields viable cells which are sensitive to UV irradiation or methyl methanesulfonate, but not to hydroxyurea. This phenotype is reminiscent of that of rad mutants and suggests that the YGL087c-encoded protein functions in a process related to tolerance to DNA damage. We also show that the mutant phenotype is fully complemented by expression of the human UEV-1A cDNA and we propose that UEV-1 proteins could also have a role in protecting higher eukaryotic cells from DNA damaging agents

Exploring matrix effects in liquid chromatography–tandem mass spectrometry determination of pesticide residues in tropical fruits

Tropical fruits are being increasingly consumed around the world because of their appreciated characteristics, particularly their high nutritional value and distinctive taste, which are different from those of traditional fruits. Owing to their introduction into international markets it is necessary to have a reliable analytical methodology available for the sensitive determination of pesticide residues in order to monitor the compliance of maximum residue limits (MRLs). From an analytical point of view, tropical fruits have generally been far less studied than other fruits frequently consumed in the European Union or USA, which are among the most important markets. In this work, LC–MS/MS-based methodology using a triple quadrupole analyzer was developed for the multi-residue determination of selected pesticides and metabolites in tropical fruits, which were selected among the most popular in Colombia, one of the most important suppliers of tropical fruits around the world. After selection of a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe)-based sample treatment, the study focused on the evaluation of matrix effects, in order to find a simple way for their correction. Twelve different food matrices were selected to perform this study: the seven Colombian tropical fruits of highest value for domestic and international markets (uchuva, tamarillo, granadilla, gulupa, maracuya, papaya, and pithaya), and five more matrices highly consumed in Colombia (lulo, carambolo, feijoa, mangostan, and guayaba). Twenty compounds, including pesticides widely applied in tropical fruits pest control and several metabolites considered in residue definition, were used as model compounds in this work. Correction factors were used on the basis of calibration graphs obtained with standards in solvent and in matrix, and their usefulness was supported by validation of the method in all the matrices tested at 0.01 and 0.1 mg/kg. The analysis of real-world samples revealed the presence of several target compounds that were identified by the acquisition of two MS/MS transitions, and by ion intensity ratio and retention time agreement.Generalitat Valenciana (Research Group of Excellence Prometeo 2009/ 054 and Prometeo II 2014/023; Collaborative Research on Environment and Food-Safety, ISIC/2012/016

Fisiopatología de los Cuerpos Libres Intraarticulares : estudio Experimental

La cubierta cartilaginosa de los cuerpos libres intraarticulares tiene un origen no bien conocido. Se ha realizado un estudio experimental en conejos, liberando fragmentos osteocondrales en la cavidad articular de la rodilla, estudiando sus cambios histológicos desde la primera semana hasta el año. En todos los casos los fragmentos osteocondrales se observaron adheridos a la membrana sinovial. Hubo una remodelación progresiva del componente óseo y cartilaginoso, cubriéndose todo el fragmento de una cubierta fibrocartilaginosa, reabsorbiéndose el hueso central y formándose nuevo hueso en la porción periférica debajo del fibrocartí- lago. Todos los cambios tisulares dependieron de la actividad de la membrana sinovial. No pudo demostrarse crecimiento del cartílago articular.It is not well known the origin of the cartilaginous outer layer of the intrarticular loose bodies. An experimental study has been carried out on rabbits loosening out osteochondral fragments into the articular cavity of the kne e joint and studying their histological changes between the first week and the first year. The osteochondral fragments wer e found adhered to the synovial membrane in all cases. A proggressive remodeling tood place within the osseous and cartilaginous components, the whole fragment became covered by a fibrocartilaginous covering, the central bone was reabsorbed and new bone was formed at the peripheral portion unde r fibrocartilage. All tissue change s wer e dependent on synovial membrane activity. Growth of articular cartilage could not be demonstrated

Cicatrización del fibrocartílago meniscal de la Rodilla : estudio Experimental

Para estudiar la cicatrización de las lesiones meniscales se ha realizado un estudio experimental en conejos. Se han practicado tres tipos de lesiones en el menisco, transversal, longitudinal parameniscal y longitudinal interna alejeda del paramenisco. Posteriormente el defecto creado era reparado mediante puntos sueltos con material reabsorvible. Se ha estudiado el fenómeno de cicatrización desde el punto de vista histológico desde la semana a los tres meses. Los resultados muestran que la cicatrización es fundamentalmente extrínseca a partir de la capacidad plástica de la membrana sinovial. Las heridas longitudinales parameniscales cicatrizaron sin dificultad, las transversales casi en toda su anchura y las longitudinales en zona avascular cicatrizaron principalmente en su porción anterior gracias a la invasión de sinovial hiperplásica desde la inserción tibial del ligamento cruzado anterior.To study the healing of meniscal tears, the authors hav e carried out an experimental work in rabbits. They performed three types of tears in the internal menisci, radial, peripheral longitudinal (in the parameniscal zone) and longitudinal within of the parameniscus. The menisci were reparated by suture with absorbible material. The healing phenomenon has been histologically studied from the first wee k to three months after. The results showed that the cicatrization is mainly extrinsic by the plastic capacity of sinovial membrane. The longitudinal tears in the parameniscus heal without difficulty, the transversal tears almost in their whol e width and the longitudinal tears at the avascular zone healed principally in the anterior portion by the invasion of hyperplasic sinovial from the tibial insertion of the anterior cruciate ligament

Fibrocartílago meniscal como biomaterial de sustitución en los Defectos Osteocondrales. Estudio experimental en el conejo con injertos homólogos

Los autores presentan un estudio experimental en el cual han empleado homoinjertos de fibrocartílago meniscal, para reparar defectos osteocondrales localizados en zona de carga, del cóndilo medial de la rodilla del conejo. Han sido estudiados 33 animales, realizando un estudio histológico, con periodos de evolución comprendidos entre una semana y 22 meses. Los homoinjertos meniscales parecen ser capaces de restaurar una superficie articular funcional. Conservan su estructura y celularidad a lo largo de toda la experiencia consiguiendo un perfecto anclaje al lecho óseo, adaptándose a la carga y sin producir cambios en el cartílago articular vecino. No se han producido rechazos.The authors report on an experimental study, employing meniscal fibrocartilage homo grafts to repair osteochondral defects in the weightbearing area of medial condile of rabbit knee. Thirty-three animals were studied by histological means for periods of one week to 22 months. The meniscal fibrocartilage homograft appeared capable of restoring a functional articular surface, maintaining its entire histological structure and celularity throughout the experiment, obtaining a perfect union with the bone tissue, adapting to the weightbearing and not modifying the neighboring articular surface. No evidence of rejection was observed

Investigation of degradation products of cocaine and benzoylecgonine in the aquatic environment

In this work, ultra-high-performance liquid chromatography (UHPLC) coupled to a hybrid quadrupole time-of-flight mass spectrometer (QTOF MS) has allowed the discovery and elucidation of degradation products of cocaine and its main metabolite benzoylecgonine (BE) in water. Spiked surface water was subjected to hydrolysis, chlorination and photo-degradation (both ultraviolet irradiation and simulated sunlight). After degradation of cocaine, up to sixteen compounds were detected and tentatively identified (1 resulting from hydrolysis; 8 from chlorination; 7 from photo-degradation), three of which are well known cocaine metabolites (BE, norbenzoylecgonine and norcocaine). Regarding BE degradation, up to ten compounds were found (3 from chlorination; 7 from photo-degradation), including one known metabolite (norbenzoylecgonine). Since reference standards were available for the major metabolites, they could be confirmed using information on retention time and fragment ions. The other degradates resulted from chlorination, dealkylation, hydroxylation and nitration, or from a combination of these processes. Several influent and effluent sewage water, and surface water samples were then screened for the identified compounds (known and unknown) using UHPLC–tandem MS with triple quadrupole. BE, norcocaine and norbenzoylecgonine were identified in these samples as major metabolites. Four previously unreported degradates were also found in some of the samples under study, illustrating the usefulness and applicability of the degradation experiments performed in this work

Identification of new omeprazole metabolites in wastewaters and surface waters

Omeprazole is one of the world-wide most consumed pharmaceuticals for treatment of gastric diseases. As opposed to other frequently used pharmaceuticals, omeprazole is scarcely detected in urban wastewaters and environmental waters. This was corroborated in a previous research, where parent omeprazole was not detected while four transformation products (TPs), mainly resulting from hydrolysis, were found in effluent wastewaters and surface waters. However, the low abundance of omeprazole TPs in the water samples together with the fact that omeprazole suffers an extensive metabolism, with a wide range of excretion rates (between 0.01 and 30%), suggests that human urinary metabolites should be investigated in the water environment. In this work, the results obtained in excretion tests after administration of a 40 mg omeprazole dose in three healthy volunteers are reported. Analysis by liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF MS) reported low concentrations of omeprazole in urine. Up to twenty-four omeprazole metabolites (OMs) were detected and tentatively elucidated. The most relevant OM was an omeprazole isomer, which obviously presented the same exact mass (m/z 346.1225), but also shared a major common fragment at m/z 198.0589. Subsequent analyses of surface water and effluent wastewater samples by both LC-QTOF MS and LC-MS/MS with triple quadrupole revealed that this metabolite (named as OM10) was the compound most frequently detected in water samples, followed by OM14a and OM14b. Up to our knowledge, OM10 had not been used before as urinary biomarker of omeprazole in waters. On the contrary, parent omeprazole was never detected in any of the water samples. After this research, it seems clear that monitoring the presence of omeprazole in the aquatic environment should be focused on the OMs suggested in this article instead of the parent compound