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Sample records for ms study suggests

  1. Community study suggests segmentation strategies.

    PubMed

    Gagnard, A

    1989-01-01

    Results of a sample survey commissioned by a voluntary health organization in a major metropolitan area describes why individuals give their time and money to charitable organizations and what approaches are likely to result in such donations. Within demographic subgroups, the variables of age and income proved to be important factors with respect to why people gave and what appeals they prefer. The variables of gender and education were found to be of somewhat less importance. Findings were compared with a national Gallup study conducted in 1987. In an era of increasingly specialized marketing for all organizations, the findings offer voluntary and fund-raising organizations a basis for determining appropriate appeals for demographic segments in a community.

  2. Suggested Format for Acute Toxicity Studies

    EPA Pesticide Factsheets

    This document suggests the format for final reports on pesticide studies (right column of the tables in the document) and provides instructions for the creation of PDF Version 1.3 electronic submission documents (left column of the tables).

  3. Physics Courses--Some Suggested Case Studies

    ERIC Educational Resources Information Center

    Swetman, T. P.

    1972-01-01

    To communicate the relevance and excitement of science activity to students, the use of more imaginative, and even openly speculative, case studies in physics courses is suggested. Some useful examples are Magnetic Monopoles, Constants, Black Holes, Antimatter, Zero Mass Particles, Tachyons, and the Bootstrap Hypothesis. (DF)

  4. Studies and Suggestions on Prewriting Activities

    ERIC Educational Resources Information Center

    Zheng, Shigao; Dai, Weiping

    2012-01-01

    This paper studies and suggests the need for writing instruction by which students can experience writing as a creative process in exploring and communicating meaning. The prewriting activities generate ideas which can encourage a free flow of thoughts and help students discover both what they want to say and how to say it on paper. Through the…

  5. Childhood Asthma May Encourage Obesity, Study Suggests

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_163160.html Childhood Asthma May Encourage Obesity, Study Suggests Fear of flare-ups might spur ... elementary school students in California, researchers found that childhood asthma ... increased risk of obesity over the next 10 years. "I was surprised ...

  6. Biomarkers of teratogenesis: suggestions from animal studies.

    PubMed

    Giavini, Erminio; Menegola, Elena

    2012-09-01

    Biomarkers of effect are measurable biochemical, physiological or other alterations within an organism that can be recognized as causing an established or potential impairment of embryo-fetal development. They may be identified studying the mechanisms of action of teratogens. Hyperacetylation of histones, oxidative stress, cholesterol and retinoic acid unbalance are some of the identified mechanisms of action of some known teratogens. Nevertheless, their use is not currently applicable in human pregnancy because of the difficulty of the choice of biological material, the time when the material must be obtained, and the invasivity of methods. Furthermore, before using them in human pregnancy studies, biomarkers should be validated in experimental animals and in epidemiologic studies. On the contrary, some biomarkers could be useful in the screening of developmental toxicity of chemicals and drugs, comparing molecules of the same chemical class or with the similar pharmacologic activity, and using adequate in vitro tests, in order to reduce the use of experimental animals.

  7. In Vivo Metabolism Study of Xiamenmycin A in Mouse Plasma by UPLC-QTOF-MS and LC-MS/MS

    PubMed Central

    Lei, Feng; Gao, Du; Zhang, Xi; Xu, Jun; Xu, Min-Juan

    2015-01-01

    Xiamenmycin A is an antifibrotic leading compound with a benzopyran skeleton that is isolated from mangrove-derived Streptomyces xiamenensis. As a promising small molecule for fibrotic diseases, less information is known about its metabolic characteristics in vivo. In this study, the time-course of xiamenmycin A in mouse plasma was investigated by relative quantification. After two types of administration of xiamenmycin A at a single dose of 10 mg/kg, the plasma concentrations were measured quantitatively by LC-MS/MS. The dynamic changes in the xiamenmycin A concentration showed rapid absorption and quick elimination in plasma post-administration. Four metabolites (M1–M4) were identified in blood by UPLC-QTOF-MS, and xiamenmycin B (M3) is the principal metabolite in vivo, as verified by comparison of the authentic standard sample. The structures of other metabolites were identified based on the characteristics of their MS and MS/MS data. The newly identified metabolites are useful for understanding the metabolism of xiamenmycin A in vivo, aiming at the development of an anti-fibrotic drug candidate for the therapeutic treatment of excessive fibrotic diseases. PMID:25636156

  8. Study Suggests Heartburn Meds-Superbug Infections Link

    MedlinePlus

    ... news/fullstory_164301.html Study Suggests Heartburn Meds-Superbug Infections Link Recurring bouts of C. difficile were ... likely to suffer recurrent bouts of a common "superbug" infection, a new study suggests. Proton pump inhibitors, ...

  9. Identification of a Novel PNMA-MS1 Gene in Marsupials Suggests the LTR Retrotransposon-Derived PNMA Genes Evolved Differently in Marsupials and Eutherians

    PubMed Central

    Iwasaki, Sawa; Suzuki, Shunsuke; Pelekanos, Matthew; Clark, Helen; Ono, Ryuichi; Shaw, Geoff; Renfree, Marilyn B.; Kaneko-Ishino, Tomoko; Ishino, Fumitoshi

    2013-01-01

    Two major gene families derived from Ty3/Gypsy long terminal repeat (LTR) retrotransposons were recently identified in mammals. The sushi-ichi retrotransposon homologue (SIRH) family comprises 12 genes: 11 in eutherians including Peg10 and Peg11/Rtl1 that have essential roles in the eutherian placenta and 1 that is marsupial specific. Fifteen and 12 genes were reported in the second gene family, para-neoplastic antigen MA (PNMA), in humans and mice, respectively, although their biological functions and evolutionary history remain largely unknown. Here, we identified two novel candidate PNMA genes, PNMA-MS1 and -MS2 in marsupials. Like all eutherian-specific PNMA genes, they exhibit the highest homology to a Gypsy12_DR (DR, Danio rerio) Gag protein. PNMA-MS1 is conserved in both Australian and South American marsupial species, the tammar wallaby and grey short-tailed opossum. However, no PNMA-MS1 orthologue was found in eutherians, monotremes or non-mammalian vertebrates. PNMA-MS1 was expressed in the ovary, mammary gland and brain during development and growth in the tammar, suggesting that PNMA-MS1 may have acquired a marsupial-specific function. However, PNMA-MS2 seems to be a pseudogene. The absence of marsupial orthologues of eutherian PNMA genes suggests that the retrotransposition events of the Gypsy12_DR-related retrotransposons that gave rise to the PNMA family occurred after the divergence of marsupials and eutherians. PMID:23704700

  10. Identification of a novel PNMA-MS1 gene in marsupials suggests the LTR retrotransposon-derived PNMA genes evolved differently in marsupials and eutherians.

    PubMed

    Iwasaki, Sawa; Suzuki, Shunsuke; Pelekanos, Matthew; Clark, Helen; Ono, Ryuichi; Shaw, Geoff; Renfree, Marilyn B; Kaneko-Ishino, Tomoko; Ishino, Fumitoshi

    2013-10-01

    Two major gene families derived from Ty3/Gypsy long terminal repeat (LTR) retrotransposons were recently identified in mammals. The sushi-ichi retrotransposon homologue (SIRH) family comprises 12 genes: 11 in eutherians including Peg10 and Peg11/Rtl1 that have essential roles in the eutherian placenta and 1 that is marsupial specific. Fifteen and 12 genes were reported in the second gene family, para-neoplastic antigen MA (PNMA), in humans and mice, respectively, although their biological functions and evolutionary history remain largely unknown. Here, we identified two novel candidate PNMA genes, PNMA-MS1 and -MS2 in marsupials. Like all eutherian-specific PNMA genes, they exhibit the highest homology to a Gypsy12_DR (DR, Danio rerio) Gag protein. PNMA-MS1 is conserved in both Australian and South American marsupial species, the tammar wallaby and grey short-tailed opossum. However, no PNMA-MS1 orthologue was found in eutherians, monotremes or non-mammalian vertebrates. PNMA-MS1 was expressed in the ovary, mammary gland and brain during development and growth in the tammar, suggesting that PNMA-MS1 may have acquired a marsupial-specific function. However, PNMA-MS2 seems to be a pseudogene. The absence of marsupial orthologues of eutherian PNMA genes suggests that the retrotransposition events of the Gypsy12_DR-related retrotransposons that gave rise to the PNMA family occurred after the divergence of marsupials and eutherians.

  11. International Pediatric MS Study Group Global Members Symposium report.

    PubMed

    Wassmer, Evangeline; Chitnis, Tanuja; Pohl, Daniela; Amato, Maria Pia; Banwell, Brenda; Ghezzi, Angelo; Hintzen, Rogier Q; Krupp, Lauren B; Makhani, Naila; Rostásy, Kevin; Tardieu, Marc; Tenembaum, Silvia; Waldman, Amy; Waubant, Emmanuelle; Kornberg, Andrew J

    2016-08-30

    The International Pediatric Multiple Sclerosis Study Group held its inaugural educational program, "The World of Pediatric MS: A Global Update," in September 2014 to discuss advances and challenges in the diagnosis and management of pediatric multiple sclerosis (MS) and other neuroinflammatory CNS disorders. Highlights included a discussion on the revised diagnostic criteria, which enable the differentiation of MS, acute disseminated encephalomyelitis, neuromyelitis optica, and other neuroinflammatory disorders. While these criteria currently identify clinical and MRI features for a particular diagnosis, advances in biomarkers may prove to be useful in the future. An update was also provided on environmental factors associated with pediatric MS risk and possibly outcomes, notably vitamin D deficiency. However, optimal vitamin D intake and its role in altering MS course in children have yet to be established. Regarding MS outcomes, our understanding of the cognitive consequences of early-onset MS has grown. However, further work is needed to define the course of cognitive function and its long-term outcome in diverse patient samples and to develop strategies for effective cognitive rehabilitation specifically tailored to children and adolescents. Finally, treatment strategies were discussed, including a need to consider additional drug treatment options and paradigms (escalation vs induction), although treatment should be tailored to the individual child. Of critical importance, clinical trials of newer MS agents in children are required. Although our understanding of childhood MS has improved, further research is needed to have a positive impact for children and their families.

  12. New approach to study of spilled crude oils using high resolution GC-MS (SIM) and metastable reaction monitoring GC-MS-MS.

    PubMed

    Munoz, D; Doumenq, P; Guiliano, M; Jacquot, F; Scherrer, P; Mille, G

    1997-12-12

    Polycyclic aromatic hydrocarbons (PAHs) and geochemical biomarkers are good environmental markers to study the origin and evolution of an oil spill. To have access to the greatest number of molecular ratios, no fractionation of oil into aliphatic and aromatic compounds is made. Three analytical MS approaches are tested to analyze markers in this total hydrocarbon fraction: classical quadrupole GC-MS, high resolution GC-MS (HR GC-MS) and metastable reaction monitoring GC-MS-MS (MRM GC-MS-MS). This analytical approach is used to follow the evolution of PAHs in petroleum polluted mangrove soils over 8 years by using molecular ratios between polycyclic aromatic hydrocarbons and tri- and tetracyclic terpanes.

  13. Know Your America: Suggested Study Course in Americanism. Revised Edition.

    ERIC Educational Resources Information Center

    American Legion, Indianapolis, IN. Americanism and Children's Youth Div.

    The purpose of this booklet is to increase understanding of fundamental U.S. documents, the U.S. flag, patriotic institutions, and of San Francisco (California), March 14-16, 1986 of U.S. residents. Unit 2 describes and interprets the code of displaying the U.S. flag and provides a suggested flag education unit of study. Units 3 and 4 offer…

  14. Histone Deacetylase Inhibitor MS-275 Exhibits Poor Brain Penetration: Pharmacokinetic Studies of [11C]MS-275 using Positron Emission Tomography

    SciTech Connect

    Hooker, J.M.; Hooker, J.M.; Kim, S.W.; Alexoff, D.; Xu, Y.; Shea, C.; Reid, A.; Volkow, N.D.; Fowler, J.S.

    2009-10-01

    MS-275 (entinostat) is a histone deacetylase (HDAC) inhibitor currently in clinical trials for the treatment of several types of cancer. Recent reports have noted that MS-275 can cross the blood-brain barrier (BBB) and cause region-specific changes in rodent brain histone acetylation. To characterize the pharmacokinetics and distribution of MS-275 in the brain using positron emission tomography (PET), we labeled the carbamate carbon of MS-275 with carbon-11. Using PET, we determined that [{sup 11}C]MS-275 has low uptake in brain tissue when administered intravenously to nonhuman primates. In rodent studies, we observed that pharmacokinetics and brain accumulation of [{sup 11}C]MS-275 were not changed by the coadministration of large doses of unlabeled MS-275. These results, which both highlight the poor brain penetration of MS-275, clearly suggest its limitation as a therapeutic agent for the central nervous system (CNS). Moreover, our study demonstrates the effectiveness of PET at providing brain pharmacokinetic data for HDAC inhibitors. These data are important not only for the development of new compounds for peripheral cancer treatment (where CNS exclusion is often advantageous) but also for the treatment of neurological disorders (where CNS penetration is critical).

  15. Positive and negative ion mode ESI-MS and MS/MS for studying drug-DNA complexes

    NASA Astrophysics Data System (ADS)

    Rosu, Frédéric; Pirotte, Sophie; Pauw, Edwin De; Gabelica, Valérie

    2006-07-01

    We report systematic investigation of duplex DNA complexes with minor groove binders (Hoechsts 33258 and 33342, netropsin and DAPI) and intercalators (daunomycin, doxorubicin, actinomycin D, ethidium, cryptolepine, neocryptolepine, m-Amsacrine, proflavine, ellipticine and mitoxantrone) by ESI-MS and ESI-MS/MS in the negative ion mode and in the positive ion mode. The apparent solution phase equilibrium binding constants can be determined by measuring relative intensities in the ESI-MS spectrum. While negative ion mode gives reliable results, positive ion mode gives a systematic underestimation of the binding constants and even a complete suppression of the complexes for intercalators lacking functional groups capable of interacting in the grooves. In the second part of the paper we systematically compare MS/MS fragmentation channels and breakdown curves in the positive and the negative modes, and discuss the possible uses and caveats of MS/MS in drug-DNA complexes. In the negative mode, the drugs can be separated in three groups: (1) those that leave the complex with no net charge; (2) those that leave the complex with a negative charge; and (3) those that remain attached on the strands upon dissociation of the duplex due to their positive charge. In the positive ion mode, all complexes fragment via the loss of protonated drug. Information on the stabilization of the complex by drug-DNA noncovalent interactions can be obtained straightforwardly only in the case of neutral drug loss. In all other cases, proton affinity (in the positive ion mode), gas-phase basicity (in the negative ion mode) and coulombic repulsion are the major factors influencing the fragmentation channel and the dissociation kinetics.

  16. Research on determinants of breastfeeding duration: suggestions for biocultural studies.

    PubMed

    Allen, L H; Pelto, G H

    1985-01-01

    The main purpose of this paper is to suggest directions for future intra-cultural research on the factors that affect breastfeeding duration, especially policy-oriented research. A 2nd purpose is to call for a reexamination of the theoretical construct, biocultural determinants, with respect to infant feeding. The study compares determinants in 4 multivariate studies. One was carried out in Connecticut, 1 in a working class community in Scotland, another in England and the 4th in Sweden. Almost no biological factors are strongly associated with breastfeeding duration in any of the population studied. Of the external factors, those relating to social support and advice were the most consistent predictors. Socioeconomic status, income, and work outside the home were not good predictors. Maternal attitudes and experience are of great importance in predicting feeding duration. The general picture that emerged from all the studies is that if a mother wants to breastfeed, she can. Mothers breastfeed longer if they desire to breastfeed; they intend to do it for a longer period of time; they feel comfortable feeding in public; they are informed about breastfeeding; and they are not anxious about the process. There is also fairly strong evidence linking a number of biocultural factors to feeding duration. Whether the linkage is biological or behavioral has significant policy implications: if it is biological, successful intervention would require a change in hospital practices to earlier 1st feeding; if the linkage is behavioral, the problem might be resolved through improved maternal education.

  17. Molecular spectroscopic study for suggested mechanism of chrome tanned leather

    NASA Astrophysics Data System (ADS)

    Nashy, Elshahat H. A.; Osman, Osama; Mahmoud, Abdel Aziz; Ibrahim, Medhat

    2012-03-01

    Collagen represents the structural protein of the extracellular matrix, which gives strength of hides and/or skin under tanning process. Chrome tan is the most important tanning agent all over the world. The methods for production of leather evolved over several centuries as art and engineering with little understanding of the underlying science. The present work is devoted to suggest the most probable mechanistic action of chrome tan on hide proteins. First the affect of Cr upon hide protein is indicated by the studied mechanical properties. Then the spectroscopic characterization of the hide protein as well as chrome tanned leather was carried out with Horizontal Attenuated Total Reflection (HATR) FT-IR. The obtained results indicate how the chromium can attached with the active sites of collagen. Molecular modeling confirms that chromium can react with amino as well as carboxylate groups. Four schemes were obtained to describe the possible interactions of chrome tan with hide proteins.

  18. International Pediatric MS Study Group Clinical Trials Summit

    PubMed Central

    Tardieu, Marc; Amato, Maria Pia; Banwell, Brenda; Bar-Or, Amit; Ghezzi, Angelo; Kornberg, Andrew; Krupp, Lauren B.; Pohl, Daniela; Rostasy, Kevin; Tenembaum, Silvia; Waubant, Emmanuelle; Wassmer, Evangeline

    2013-01-01

    Objective: Pediatric studies for new biological agents are mandated by recent legislation, necessitating careful thought to evaluation of emerging multiple sclerosis (MS) therapies in children with MS. Challenges include a small patient population, the lack of prior randomized clinical trials, and ethical concerns. The goal of this meeting was to assess areas of consensus regarding clinical trial design and outcome measures among academic experts involved in pediatric MS care and research. Methods: The Steering Committee of the International Pediatric MS Study Group identified key focus areas for discussion. A total of 69 meeting attendees were assembled, including 35 academic experts. Regulatory and pharmaceutical representatives also attended, and provided input, which informed academic expert consensus decisions. Results: The academic experts agreed that clinical trials were necessary in pediatric MS to obtain pharmacokinetic, safety and efficacy data, and regulatory approval allowing for greater medication access. The academic experts agreed that relapse was an appropriate primary outcome measure for phase III pediatric trials. An international standardized cognitive battery was identified. The pros and cons of various trial designs were discussed. Guidelines surrounding MRI studies, pharmacokinetics, pharmacodynamics, and registries were developed. The academic experts agreed that given the limited subject pool, a stepwise approach to the launch of clinical trials for the most promising medications is necessary in order to ensure study completion. Alternative approaches could result in unethical exposure of patients to trial conditions without gaining knowledge. Conclusion: Consensus points for conduct of clinical trials in the rare disease pediatric MS were identified amongst a panel of academic experts, informed by regulatory and industry stakeholders. PMID:23509048

  19. Pharmacokinetics, tissue distribution, and plasma protein binding study of chicoric acid by HPLC-MS/MS.

    PubMed

    Wang, Yutang; Xie, Guo; Liu, Qian; Duan, Xiang; Liu, Zhigang; Liu, Xuebo

    2016-09-15

    Chicoric acid is a major active constituent of Echinacea purpurea and has a variety of biological functions. In this study, a liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) approach was developed and validated for the determination of chicoric acid in rat plasma and various tissues using ferulic acid as an internal standard (IS). This method was successfully applied to pharmacokinetics, tissue distribution, and plasma protein binding (PPB) study of chicoric acid in Sprague-Dawley (SD) rats dosed with 50mg/kg by gastric gavage. The pharmacokinetic parameters were determined and showed a half-life (t1/2) of 4.53±1.44h, an apparent volume of mean residual time (MRT) of 18.58±4.43h, and an area under the curve (AUC) of 26.14 mghL(-1). The tissue distribution of chicoric acid in rats after gavage administration showed a decreasing tendency in different tissues (liver>lung>kidney>heart>spleen>brain). The PPB rates in rat plasma, human plasma, and bovine serum albumin were 98.3, 96.9, and 96.6%, respectively. These results provide insight for the further pharmacological investigation of chicoric acid.

  20. Animal Rights: Selected Resources and Suggestions for Further Study.

    ERIC Educational Resources Information Center

    Davidoff, Donald J.

    1989-01-01

    Presents an annotated list of selected resources intended to serve as a guide to the growing amount of material on animal rights. Suggestions to aid in additional research include subject headings used to find books, indexes used to locate periodical articles, sources for locating organizations, and a selected list of animal rights organizations.…

  1. Studies and Suggestions on English Vocabulary Teaching and Learning

    ERIC Educational Resources Information Center

    Zheng, Shigao

    2012-01-01

    To improve vocabulary learning and teaching in ELT settings, two questionnaires are designed and directed to more than 100 students and teachers in one of China's key universities. The findings suggest that an enhanced awareness of cultural difference, metaphorical competence, and learners' autonomy in vocabulary acquisition will effectively…

  2. A novel study of screening and confirmation of modafinil, adrafinil and their metabolite modafinilic acid under EI-GC-MS and ESI-LC-MS-MS ionization

    PubMed Central

    Dubey, S.; Ahi, S.; Reddy, I. M.; Kaur, T.; Beotra, A.; Jain, S.

    2009-01-01

    Objective: Adrafinil and modafinil have received wide publicity and have become controversial in the sporting world when several athletes were discovered allegedly using these drugs as doping agents. By acknowledging the facts, the World Anti-Doping Agency (WADA) banned these drugs in sports since 2004. The present study explores the possibility of differentiating adrafinil and modafinil and their major metabolites under electron impact ionization in gas chromatograph–mass spectrometer (GC-MSD) and electrospray ionization in liquid chromatograph–mass spectrometer (LC-MS/MS) by studying the fragmentation pattern of these drugs. Materials and Methods: Adrafinil, modafinil and their major metabolite, modafinilic acid were analyzed on EI-GC-MSD and ESI-LC-MS/MS using various individual parameters on both the instruments. The analytical technique and equipment used in the analysis were an Agilent 6890N GC with 5973 mass selective detector for the GC-MSD analysis and an Agilent 1100 HPLC with API-3200 Triple quadrupole mass spectrometer for the LC-MS/MS analysis. Validation of both methods was performed using six replicates at different concentrations. Result and Discussion: The results show that adrafinil, modafinil and their major metabolite modafinilic acid could be detected as a single artifact without differentiation under EI-GC-MSD analysis. However, all drugs could be detected and differentiated under ESI-LCMS/MS analysis without any artifaction. The GC-MSD analysis gives a single artifact for both the drugs without differentiation and thus can be used as a marker for screening purposes. Further, the Multiple Reaction Monitoring (MRM) method developed under LC-MS/MS is fit for the purpose for confirmation of suspicious samples in routine sports testing and in forensic and clinical analysis. PMID:20407560

  3. Pharmacokinetic studies and LC-MS/MS method development of ganciclovir and dipeptide monoester prodrugs in Sprague Dawley rats.

    PubMed

    Gunda, Sriram; Earla, Ravinder; Cholkar, Kishore; Mitra, Ashim K

    2015-09-01

    Ganciclovir (GCV) is utilized as an anti-herpetic agent. Reports from our laboratory have suggested that dipeptide ester prodrugs of GCV exhibit high affinity towards the oligopeptide transporter hPEPT1 and therefore seem to be promising candidates for the treatment of oral herpes virus infections. In this study, we have examined the bio-availability of a dipeptide prodrug of GCV after oral administration in jugular cannulated Sprague-Dawley rats. A new bio-analytical method was developed with Q-TRAP liquid chromatography tandem mass spectroscopy (LC-MS/MS) for simultaneous analysis of GCV, Valine-GCV (VGCV) and Tyrosine-Valine-GCV (YVGCV). Acyclovir (ACV) was used as an internal standard in the analysis. Area under plasma-concentration time curves for total concentration of GCV after oral administration of YVGCV was found to be approximately 200 % more than that of GCV following intestinal absorption. A complete conversion of the dipeptide prodrug (YVGCV) to parent compound, GCV, by hepatic first-pass metabolism was evident due to the absence of intermediate metabolite VGCV and administered prodrug YVGCV. The dipeptide prodrugs of GCV exhibit higher systemic availability of regenerated GCV upon oral administration and thus seem to be promising drug candidate in the treatment of systemic herpes infections.

  4. Pediatric MS

    MedlinePlus

    ... with Others on MSconnection.org Join a Local Support Group Ask an MS Navigator Edward M. Dowd Personal ... navigate the school system through the Pediatric MS Support Group . Treating pediatric MS Studies have shown that the ...

  5. First Major Study Suggests Worth of National "Seal"

    ERIC Educational Resources Information Center

    Jacobson, Linda

    2004-01-01

    The first in a series of long-awaited studies indicates that nationally certified teachers are more effective at raising their students' reading and math scores than are teachers who apply for the credential but do not receive it. Although critics have questioned the expenditure of state and district money on National Board for Professional…

  6. Khat Use and Neurobehavioral Functions: Suggestions for Future Studies

    PubMed Central

    Hoffman, Richard; al’Absi, Mustafa

    2010-01-01

    Although there is a rich body of research available regarding the effect of acute and chronic khat dosing in animal models, research on the behavioral and cognitive effects of khat in human subjects is not extensive and several of the available studies have been done only in the context of observational and single-case studies. In light of the absence of a substantial literature on the neurobehavioral deficits associated with khat use and to provide a context that could be used to identify themes for future research we review previous research that has focused on other stimulant drugs. This review highlights multiple areas of neurocognitive deficit that have been identified in previous studies of individuals who have been chronic users of stimulants, such as amphetamines and methamphetamines. The review highlights a substantial body of evidence demonstrating a wide range of learning and memory impairments including deficits that persist during abstinence from active drug use. This review does not imply a similar khat effect, but due to some similarities pharmacologically between the active components of khat (cathinone and cathine) and amphetamines, future studies examining these same domains of cognitive functioning in chronic khat users and abstinent khat users appears to be warranted, if possible using some of the same or similar laboratory measures. PMID:20553832

  7. Directions in Geoheritage Studies: Suggestions from the Italian Geomorphological Community

    NASA Astrophysics Data System (ADS)

    Panizza, Valeria

    2015-04-01

    More and more attention has been focused on geological and geomorphological heritage in the past years, leading to several researches in the framework of conservation projects, both at administrative and at scientific level, involving national and international research groups whose purposes are the promotion of Earth Sciences knowledge and the conservation of geological heritage. This paper presents an overview of research and conservation projects in Italy, mainly focused on the geomorphological heritage. Members of the AIGEO Working Group on geomorphosites and cultural landscape analyzed the historical development, methodological issues and main results of these research projects in order to identify possible innovation lines to improve the awareness and knowledge on geodiversity and geoheritage by a wide public, including education, tourism and conservation sectors. In Italy numerous projects of research have been realized with the main aim of geomorphosites inventory and the proposal of assessment methodologies, and so to the improvement and to the analysis of risks and impacts related to their fruition. At an international level, many Italian researchers have also been involved in studies carried out in the Working Group "Geomorphological sites" of the International Association of Geomorphologists (IAG). At a national level several research lines are under development, offering different responses to methodological issues within the general topic of geodiversity and geoheritage: Geosites inventories and assessment activities are performed with powerful digital techniques and new reference models: among these, the investigation on the ecologic support role for increasing geomorphosites global value and the elaboration of quantitative assessment methods of the scientific quality of Geomorphosites, carried out specifically for territorial planning. Improvements in field data collection and visual representation of landforms lead to new findings in

  8. [Study on chemical constituents in stems of Nelumbo nucifera by UPLC-ESI/Q-TOF-MS/MS].

    PubMed

    Shan, Feng; Yuan, Yuan; Kang, Li-ping; Huang, Lu-qi

    2015-08-01

    This paper employed UPLC-Electrospray Ionization /Quadrupole-Time of Flight-Mass /Mass Spectrometry( UPLC-ESI/Q-TOF-MS/MS) to analyze the chemical constituents in the stems of Nelumbo nucifera. The stems of N. nucifera were extracted with 75% methanol, and we applied an Agilent Zorbax SB-Aq column (2.1 mm x 100 mm, 1.8 μm) to UPLC analysis with water methanol-water( containing 0.05% formic acid) in gradient as mobile phase. The eluates were then detected by ESI-Q-TOF-MS/MS. Results indicated that 22 benzylisoquinoline alkaloids were indendified. Among them, one alkaloid may be a new compound and a component was found in the Lotus for the first time. We fully identify the composition of the Lotus stems for the first time, Which could provides theoretical foundation for further study and utilization of the medicinal resources.

  9. LC-MS/MS method for the determination of melamine in rat plasma: toxicokinetic study in Sprague-Dawley rats.

    PubMed

    Yang, Feng; Mao, Yu; Zhang, Xiaodong; Ma, Zhiqiang; Zhang, Xinrong

    2009-09-01

    Most recently, melamine has raised international concern for its catastrophic health effects stemming from tainted infant formula. So far there is limited information concerning the pharmacokinetics of melamine in mammals. The present report concerns the development and validation of a sensitive HPLC-ESI-MS/MS method for the pharmacokinetic study of melamine in rat. The method employed a simple liquid-liquid extraction process for plasma sample cleanup, and the extraction recoveries of melamine from plasma were consistent at different concentrations. There was a linear relationship between chromatographic area and concentration over the range of 10-5000 ng/mL for melamine in plasma (R = 0.995). In this work, for the first time, melamine was administered intravenously and orally to Sprague-Dawley rats and the pharmacokinetic characteristics of this contaminant were investigated. The mean values of major pharmacokinetic parameters of oral availability, the mean steady-state distribution volume (V(ss)), clearance, and plasma elimination half-life (T(1/2)) of melamine in Sprague-Dawley rats were 72.9 +/- 13.2%, 102.5 +/- 12.5 mL/kg, 20.1 +/- 3.8 mL/h/kg, and 4.9 +/- 0.5 h, respectively. The rats pharmacokinetic study results suggested that melamine was predominantly restricted to blood or extracellular fluid and is not extensively distributed to most organ tissues. Meanwhile, melamine should be primarily eliminated by renal filtration for rats and does not undergo significant metabolism. These data should be useful to regulatory for risk assessment.

  10. LC-MS/MS determination of etravirine in rat plasma and its application in pharmacokinetic studies.

    PubMed

    Abobo, Cyril V; Wu, Lei; John, Jyothy; Joseph, Mathew K; Bates, Theodore R; Liang, Dong

    2010-11-15

    Etravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that is active against NNRT-resistant HIV-1. A simple, sensitive, and specific LC-MS/MS method was developed and validated for the analysis of etravirine in rat plasma using itraconazole as the internal standard. The analytes were extracted with ethyl acetate and chromatographed on a reverse-phase XTerra MS C₁₈ column. Elution was achieved with a mobile phase gradient varying the proportion of a 2 mM ammonium acetate aqueous solution containing 0.1% formic acid (solvent A) and a 0.1% formic acid in methanol solution (solvent B) at a flow rate of 300 μL/min. The analytes were monitored by tandem-mass spectrometry with positive electrospray ionization. The precursor/product transitions (m/z) in the positive ion mode were 435.9→163.6 and 706.7→392.6 for etravirine and the internal standard, respectively. Calibration curves were linear over the etravirine rat plasma concentration range of 1-100 ng/mL. The inter- and intra-day accuracy and precision were within ±10%. The assay has been successfully used for pharmacokinetic evaluation of etravirine using the rat as an animal model.

  11. LC-MS/MS determination of etravirine in rat plasma and its application in pharmacokinetic studies

    PubMed Central

    Abobo, Cyril; Wu, Lei; John, Jyothy; Joseph, Mathew K.; Bates, Theodore R.; Liang, Dong

    2010-01-01

    Etravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that is active against NNRT-resistant HIV-1. A simple, sensitive, and specific LC-MS/MS method was developed and validated for the analysis of etravirine in rat plasma using itraconazole as the internal standard. The analytes were extracted with ethyl acetate and chromatographed on a reverse-phase XTerra MS C18 column. Elution was achieved with a mobile phase gradient varying the proportion of a 2 mM ammonium acetate aqueous solution containing 0.1% formic acid (solvent A) and a 0.1% formic acid in methanol solution (solvent B) at a flow rate of 300 μL/min. The analytes were monitored by tandem-mass spectrometry with positive electrospray ionization. The precursor/product transitions (m/z) in the positive ion mode were 435.9→163.6 and 706.7→392.6 for etravirine and the internal standard, respectively. Calibration curves were linear over the etravirine rat plasma concentration range of 1 ng/mL to 100 ng/mL. The inter- and intra-day accuracy and precision were within ±10%. The assay has been successfully used for pharmacokinetic evaluation of etravirine using the rat as an animal model. PMID:20965798

  12. [Study on determination of caffeic acid, chlorogenic acid in rat plasma and their pharmacokinetics with LC-MS/MS].

    PubMed

    Dai, Guo-Liang; Ma, Shi-Tang; Liu, Shi-Jia; Cheng, Xiao-Gui; Zang, Yu-Xin; Ju, Wen-Zheng; Tan, Heng-Shan

    2013-11-01

    To establish a LC-MS/MS method to determine caffeic acid, chlorogenic acid in rat plasma and study their pharmacokinetics in rats. Six Sprague-Dawley rats were intravenously injected with 4 mL x kg(-1) of Dengzhanxixin injection, respectively. Their drug plasma concentration was determined by LC-MS/MS, with tinidazole as an internal standard. The pharmacokinetic parameters were calculated by DAS 1.0. The linear concentration ranges of caffeic acid, and chlorogenic acid were 2-128 microg x L(-1) (r = 0.998 1) and 3-384 microg x L(-1) (r = 0.998 7), respectively. The methodological test showed conformance to the requirements. The intraday and inter-day variable coefficients were both less than 10.0%, indicating that both of legitimate precise and accuracy were in conformity with the requirements of biological sample analysis. For caffeic acid, the pharmacokinetic parameter t1/2beta AUC0-t, and CL were (130.91 +/- 38.77) min, (4.89 +/- 0.96) mg x min x L(-1) and (0.12 +/- 0.02) L x min(-1) x kg(-1), respectively. For chlorogenic acid, the pharmacokinetic parameter t1/2beta , AUC0-t, and CL were (49.38 +/- 8.85) min, (9.54 +/- 0.95) mg x min x L(-1) and (0.09 +/- 0.003) L x min(-1) x kg(-1), respectively. The LC-MS/MS analysis method established in this study was proved to be so accurate and sensitive that it can be applied to the pharmacokinetic study of caffeic acid and chlorogenic acid.

  13. Analytical power of LLE-HPLC-PDA-MS/MS in drug metabolism studies: identification of new nabumetone metabolites.

    PubMed

    Nobilis, Milan; Mikušek, Jiří; Szotáková, Barbora; Jirásko, Robert; Holčapek, Michal; Chamseddin, Chamseddin; Jira, Thomas; Kučera, Radim; Kuneš, Jiří; Pour, Milan

    2013-06-01

    Nabumetone is a non-acidic, nonsteroidal anti-inflammatory prodrug. Following oral administration, the prodrug is converted in the liver to 6-methoxy-2-naphthylacetic acid (6-MNA), which was found to be the principal metabolite responsible for the NSAID effect. The pathway of nabumetone transformation to 6-MNA has not been clarified, with no intermediates between nabumetone and 6-MNA having been identified to date. In this study, a new, as yet unreported phase I metabolite was discovered within the evaluation of nabumetone metabolism by human and rat liver microsomal fractions. Extracts from the biomatrices were subjected to chiral LLE-HPLC-PDA and achiral LLE-UHPLC-MS/MS analyses to elucidate the chemical structure of this metabolite. UHPLC-MS/MS experiments detected the presence of a structure corresponding to elemental composition C15H16O3, which was tentatively assigned as a hydroxylated nabumetone. Identical nabumetone and HO-nabumetone UV spectra obtained from the PDA detector ruled out the presence of the hydroxy group in the aromatic moiety of nabumetone. Hence, the most likely structure of the new metabolite was 4-(6-methoxy-2-naphthyl)-3-hydroxybutan-2-one (3-hydroxy nabumetone). To confirm this structure, the standard of this nabumetone metabolite was synthesized, its spectral (UV, CD, NMR, MS/MS) and retention properties on chiral and achiral chromatographic columns were evaluated and compared with those of the authentic nabumetone metabolite. To elucidate the subsequent biotransformation of 3-hydroxy nabumetone, the compound was used as a substrate in incubation with human and rat liver microsomal fraction. A number of 3-hydroxy nabumetone metabolites (products of conjugation with glucuronic acid, O-desmethylation, carbonyl reduction and their combination) were discovered in the extracts from the incubated microsomes using LLE-HPLC-PDA-MS/MS experiments. On the other hand, when 3-hydroxy nabumetone was incubated with isolated rat hepatocytes, 6-MNA was

  14. Degradation studies of cholecalciferol (vitamin D3) using HPLC-DAD, UHPLC-MS/MS and chemical derivatization.

    PubMed

    Mahmoodani, Fatemeh; Perera, Conrad O; Fedrizzi, Bruno; Abernethy, Grant; Chen, Hong

    2017-03-15

    In any food fortification program, the stability of added micronutrients is an important factor. Cholecalciferol or vitamin D3 is known to isomerise under various conditions, thereby making its analysis challenging. In the current study, the effects of different parameters, such as temperature, iodine, acidic conditions, and oxidation, on the isomerisation of vitamin D3 were studied using HPLC-DAD and UHPLC-MS/MS. Vitamin D3 thermally and reversibly transforms to pre-vitamin D3 type isomers. In the presence of iodine, cis/trans isomerisation of both cholecalciferol and pre-vitamin D3 takes place to form trans-vitamin D3 and tachysterol, respectively. Another isomer, isotachysterol, was formed under acidic conditions. The different rates of reaction of these products with a dienophile through the Diels-Alder reaction confirmed the formation of vitamin D3 isomerisation products. The derivatization enhanced the ionisation efficiency of vitamin D3 and its isomers in UHPLC-MS/MS and improved the separation and fragmentation enabling sensitive detection.

  15. Determination of free and glucuronidated kaempferol in rat plasma by LC-MS/MS: application to pharmacokinetic study.

    PubMed

    Zhang, Wei-Dong; Wang, Xiao-Juan; Zhou, Si-Yuan; Gu, Yi; Wang, Rong; Zhang, Tao-Li; Gan, Hong-Quan

    2010-08-01

    Flavanoid kaempferol is mainly present as glucuronides and sulfates in rat plasma, and small amounts of the intact aglycone are also detected. In the this study, a rapid, specific and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry method (HPLC-MS/MS) was developed and validated for determination of kaempferol and its major metabolite glucuronidated kaempferol in rat plasma. A liquid-liquid extraction with acetic ether was involved for the extraction of kaempferol and internal standard. Analytes were separated on a C18 column (150 mm x 2.1 mm, 4.5 microm, Waters Corp.) with isocratic elution at a flow-rate of 0.3 ml min(-1). The mobile phase was consisted of 0.5% formic acid and acetonitrile (50:50, v/v). The Quattro Premier HPLC-MS/MS was operated under the multiple reaction-monitoring mode (MRM) using the electrospray ionization technique. The method was validated according to the FDA guidelines for validation of bioanalytical method. The validated method was successfully applied to the study of the pharmacokinetics in rats after oral administration of kaempferol with different doses.

  16. A rapid LC-MS/MS method for quantitation of eszopiclone in human plasma: application to a human pharmacokinetic study.

    PubMed

    Hotha, Kishore Kumar; Vijaya Bharathi, D; Jagadeesh, B; Ravindranath, L K; Jaya Veera, K N; Venkateswarulu, V

    2012-02-01

    A highly reproducible, specific and cost-effective LC-MS/MS method was developed for simultaneous estimation of eszopiclone (ESZ) with 50 μL of human plasma using paroxetine as an internal standard (IS). The API-4000 LC-MS/MS was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. A simple liquid-liquid extraction process was used to extract ESZ and IS from human plasma. The total run time was 1.5 min and the elution of ESZ and IS occurred at 0.90 min; this was achieved with a mobile phase consisting of 0.1% formic acid-methanol (15:85, v/v) at a flow rate of 0.50 mL/min on a Discover C(18) (50 × 4.6 mm, 5 µm) column. The developed method was validated in human plasma with a lower limit of quantitation of 0.1 ng/mL for ESZ. A linear response function was established for the range of concentrations 0.10-120 ng/mL (r > 0.998) for ESZ. The intra- and inter-day precision values for ESZ were acceptable as per FDA guidelines. Eszopiclone was stable in the battery of stability studies, viz. bench-top, autosampler and freeze-thaw cycles. The developed assay method was applied to an oral bioequivalence study in humans.

  17. Novel and sensitive UPLC-MS/MS method for quantification of sofosbuvir in human plasma: application to a bioequivalence study.

    PubMed

    Rezk, Mamdouh R; Basalious, Emad B; Amin, Mohammed E

    2016-09-01

    A novel and sensitive LC-MS/MS method was developed and validated for determination of sofosbuvir (SF) using eplerenone as an internal standard. The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Extraction with tert-butyl methyl ether was used in sample preparation. The prepared samples were chromatographed on Acquity UPLC BEH C18 (50 × 2.1 mm, 1.7 μm) column by pumping 0.1% formic acid and acetonitrile in an isocratic mode at a flow rate of 0.35 mL/min. Method validation was performed as per the US Food and Drug Administration guidelines and the standard curves were found to be linear in the range of 0.25-3500 ng/mL for SF. The intra- and inter-day precision and accuracy results were within the acceptable limits. A very short run time of 1 min made it possible to analyze more than 500 human plasma samples per day. A very low quantification limit of SF allowed the applicability of the developed method for determination of SF in a bioequivalence study in human volunteers. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Determination of plasma topiramate concentration using LC-MS/MS for pharmacokinetic and bioequivalence studies in healthy Korean volunteers.

    PubMed

    Park, Jin-Hee; Park, Yoo-Sin; Lee, Min-Ho; Rhim, Si-Youn; Song, Jae-Chul; Lee, Soo-Jin; Kim, Jung-Mogg; Shaw, Leslie M; Kang, Ju-Seop

    2008-08-01

    A rapid, simple and validated liquid chromatography coupled to tandem mass spectrometric method (LC-MS/MS) for topiramate analysis in human plasma has been applied to pharmacokinetic and bioequivalence studies in 24 healthy male Korean volunteers. The procedure involves a simple liquid extraction of topiramate and prednisone (internal standard) with acetonitrile and separation by HPLC equipped with a Capcell Pak C18 column using acetonitrile-0.1% triethylamine (80:20, v/v) as a mobile phase. Detection was carried out on an API 2000 MS system by multiple reactions monitoring mode. The ionization was optimized using ESI(-) and selectivity was achieved by MS/MS analysis, m/z 338.0 --> 77.5 and m/z 357.1 --> 327.2 for topiramate and prednisone, respectively. The method had a total run time of 2.5 min and showed good linearity over a working range of 20-5000 ng/mL in human plasma with a lower limit of quantification of 20 ng/mL. No metabolic compounds were found to interfere with the analysis. The inter-day and intra-day accuracy were in the ranges of 99.24-116.63 and 93.45-108.68%, respectively, and inter-day and intra-day precisions were below 6.24 and 5.25%, respectively. This method was successfully applied for pharmacokinetic and bioequivalence studies by analysis of blood samples taken up to 96 h after an oral administration of 100 mg of topiramate in 24 healthy Korean volunteers.

  19. Competence-Based System Self-Study System for Suggesting Study Materials Links

    ERIC Educational Resources Information Center

    Nitchot, Athitaya; Gilbert, Lester; Wills, Gary B.

    2014-01-01

    The article proposes a self-study system which suggests web links to learners. The suggestions depend upon the learner's chosen competences selected from a competence structure for a particular knowledge domain. Three experiments were conducted, where the first compared the perceived usefulness and value of the links generated by different…

  20. Determination of levocetirizine in human plasma by LC-MS-MS: validation and application in a pharmacokinetic study.

    PubMed

    Wichitnithad, Wisut; Jithavech, Ponsiree; Sanphanya, Kingkan; Vicheantawatchai, Petploy; Rojsitthisak, Pornchai

    2015-01-01

    A fast and simple sample cleanup approach for levocetirizine in human was developed using protein precipitation coupled with LC-MS-MS. Samples were treated with 6% trichloroacetic acid in water prior to LC-MS-MS analysis. Chromatographic separation was performed on a reverse phase column with an isocratic mobile phase of acetonitrile and 10 mM ammonium formate pH 3.5 (80:20, v/v) at a flow rate of 1.0 mL/min. The run time was 3.5 min. Mass parameters were optimized to monitor transitions at m/z [M+H](+) 389.0→201.0 for levocetirizine and m/z [M+H](+) 375.3→201.0 for hydroxyzine as internal standard. The lower limit of quantification and the dynamic range were 1.00 and 1.00-500 ng/mL, respectively. Linearity was good for intraday and interday validations (r(2) ≥ 0.995). The mean recoveries were 59 and 69% for levocetirizine and hydroxyzine, respectively. Matrix effect was acceptable with %CV < 15. Hemolytic effect was negligible. Levocetirizine was stable in human plasma for 27 h at room temperature (25°C), for 16 weeks frozen at -70°C, 4 weeks frozen at -20°C, for 24 h in an autosampler at 15°C and for three freeze/thaw cycles. The validated method was applied in a pharmacokinetic study to determine the concentration of levocetirizine in plasma samples. The study provides a fast and simple bioanalytical method for routine analysis and may be particularly useful for bioequivalence studies.

  1. LC–MS/MS assay for quantitation of enalapril and enalaprilat in plasma for bioequivalence study in Indian subjects

    PubMed Central

    Halder, Dhiman; Dan, Shubhasis; Pal, Murari Mohun; Biswas, Easha; Chatterjee, Nilendra; Sarkar, Pradipta; Halder, Umesh Chandra; Pal, Tapan Kumar

    2017-01-01

    Background: Enalapril (EPL) is an angiotensin-converting enzyme inhibitor for the treatment of hypertension and chronic heart failure. Enalaprilat (EPLT) is an active metabolite that contributes to the overall activity of EPL. Aim: To quantitate EPL along with its metabolite EPLT using LC–MS/MS, a bioanalytical method was developed and validated with tolbutamide in human plasma using a protein precipitation technique. Results: The sensitive and selective method has an LLOQ of 1 ng/ml with a linearity range of 1–500 ng/ml for both EPL and EPLT using 300 µl of plasma without any matrix effect. Conclusion: Linearity, specificity, accuracy, precision and stability, as well as its application to the analysis of plasma samples after oral administration of 20 mg of EPL maleate in healthy volunteers demonstrate applicability to bioavailability/bioequivalence studies. PMID:28344828

  2. Mass spectrometry of rhenium complexes: a comparative study by using LDI-MS, MALDI-MS, PESI-MS and ESI-MS.

    PubMed

    Petroselli, Gabriela; Mandal, Mridul Kanti; Chen, Lee Chuin; Ruiz, Gustavo T; Wolcan, Ezequiel; Hiraoka, Kenzo; Nonami, Hiroshi; Erra-Balsells, Rosa

    2012-03-01

    A group of rhenium (I) complexes including in their structure ligands such as CF(3)SO(3)-, CH(3)CO(2)-, CO, 2,2'-bipyridine, dipyridil[3,2-a:2'3'-c]phenazine, naphthalene-2-carboxylate, anthracene-9-carboxylate, pyrene-1-carboxylate and 1,10-phenanthroline have been studied for the first time by mass spectrometry. The probe electrospray ionization (PESI) is a technique based on electrospray ionization (ESI) that generates electrospray from the tip of a solid metal needle. In this work, mass spectra for organometallic complexes obtained by PESI were compared with those obtained by classical ESI and high flow rate electrospray ionization assisted by corona discharge (HF-ESI-CD), an ideal method to avoid decomposition of the complexes and to induce their oxidation to yield intact molecular cation radicals in gas state [M](+·) and to produce their reduction yielding the gas species [M](-·). It was found that both techniques showed in general the intact molecular ions of the organometallics studied and provided additional structure characteristic diagnostic fragments. As the rhenium complexes studied in the present work showed strong absorption in the UV-visible region, particularly at 355 nm, laser desorption ionization (LDI) mass spectrometry experiments could be conducted. Although intact molecular ions could be detected in a few cases, LDI mass spectra showed diagnostic fragments for characterization of the complexes structure. Furthermore, matrix-assisted laser desorption ionization (MALDI) mass spectra were obtained. Nor-harmane, a compound with basic character, was used as matrix, and the intact molecular ions were detected in two examples, in negative ion mode as the [M](-·) species. Results obtained with 2-[(2E)-3-(4-tert-buthylphenyl)-2-methylprop-2-enylidene] malononitrile (DCTB) as matrix are also described. LDI experiments provided more information about the rhenium complex structures than did the MALDI ones.

  3. UHPLC-MS/MS Determination, Pharmacokinetic, and Bioavailability Study of Taxifolin in Rat Plasma after Oral Administration of its Nanodispersion.

    PubMed

    Yang, Chun-Juan; Wang, Zhi-Bin; Mi, Ying-Ying; Gao, Ming-Jie; Lv, Jin-Nan; Meng, Yong-Hai; Yang, Bing-You; Kuang, Hai-Xue

    2016-04-14

    A rapid and sensitive LC-MS/MS method based on the Triple Quad system has been developed and validated for the determination and pharmacokinetics of taxifolin and its nanodispersion in rat plasma. Taxifolin plasma samples along with butylparaben (internal standard) were pre-treated by liquid-liquid extraction with ethyl acetate, and then separated on a SB-C18 RRHD column (150 mm × 2.1 mm × 1.8 μm) using isocratic elution with a run time of 3.0 min. The mobile phase was acetonitrile-water (90:10, v/v) containing 5 mM ammonium acetate at a flow rate of 0.4 mL/min. Quantification of taxifolin was performed by the electrospray ionization tandem mass spectrometry in the multiple reaction monitoring (MRM) mode with negative atmospheric ionization at m/z 303.0→285.0 for taxifolin and 193.1→92.0 for I.S., respectively. The calibration curve of taxifolin showed good linearity over a concentration range of 5.0-4280 ng/mL with a correlation coefficient of 0.9995. The limit of quantification (LLOQ) was 5.0 ng/mL. Intra-day, inter-day precision and accuracy (percent relative to standard deviation) were all within 8% at three concentration levels. A total recovery of taxifolin and I.S. was beyond 75%. The present LC-MS/MS method was successfully applied to pharmacokinetic studies of taxifolin after intravenous administration of taxifolin, oral administration of its physical mixture and nanodispersion. The absolute bioavailability of taxifolin was calculated as 0.75% for taxifolin nanodispersion and 0.49% for taxifolin, respectively.

  4. High-Throughput Analytical Techniques for the Determination of the Residues of 653 Multiclass Pesticides and Chemical Pollutants in Tea, Part VII: A GC-MS, GC-MS/MS, and LC-MS/MS Study of the Degradation Profiles of Pesticide Residues in Green Tea.

    PubMed

    Chang, Qiao-Ying; Pang, Guo-Fang; Fan, Chun-Lin; Chen, Hui; Yang, Fang; Li, Jie; Wen, Bi-Fang

    2016-11-01

    GC-MS, GC-tandem MS (MS/MS), and LC-MS/MS were used to mathematically define the degradation profiles of pesticide residues in two field trials. Nineteen pesticides were studied in the first field trial and 11 in the second. The results of the field trials demonstrated that the degradation profiles of pesticide residues in green tea can be described with power functions to successfully estimate the amount of time, following pesticide application, pesticide residues appearing in tea in concentrations at and/or above the maximum residue limit (MRL) decrease to concentrations below the MRL. Stability tests on green tea samples stored at room temperature were conducted to determine whether pesticide-incurred green tea samples prepared according to the method used in the field trials would be suitable for the preparation of reference standards for laboratory-proficiency testing trials. This paper reports the results of a GC-MS, GC-MS/MS, and LC-MS/MS study, as well as the suitability of the samples prepared under these conditions for use as pesticide reference standards in tea analysis.

  5. Rapid LC-MS/MS method for determination of drotaverine in a bioequivalence study.

    PubMed

    Vancea, Szende; Gáll, Zsolt; Donáth-Nagy, Gabriella; Borka-Balás, Réka

    2014-09-01

    A liquid chromatography coupled with tandem mass spectrometry method for the quantification of the antispasmodic drug drotaverine in human plasma was developed and validated according to the current bioanalytical guidelines. The internal standard used was imipramine. The separation was performed on a Kinetex C18 50×3mm, 2.6μm column under isocratic conditions using a mobile phase of 65:35 (v/v) formic acid 0.2% (v/v) in water and acetonitrile at 40°C with a flow rate of 0.4ml/min. The detection of drotaverine and the internal standard was performed in multiple reaction monitoring (MRM) mode using an ion trap mass spectrometer with electrospray ionization, operating in positive mode. The human plasma samples (0.24ml) were deproteinized with methanol and aliquots of 4μl from supernatants obtained after centrifugation were directly injected into the chromatographic system. The method shows a good linearity (r(2)>0.997), precision (CV<6.3%) and accuracy (bias<5.4%) over the range of 2.24-448ng/ml drotaverine in plasma. The recovery was between 91 and 98%. The limit of quantification was 2.24ng/ml. The analysis required only a 3.0min run. The developed and validated method for the determination of drotaverine in human plasma was successfully applied in a bioequivalence study, for analyzing approximately 1000 subject's samples.

  6. Determination and pharmacokinetic study of norcantharidin in human serum by HPLC-MS/MS method.

    PubMed

    Wei, Chun-min; Zhang, Rui; Wang, Ben-jie; Yuan, Gui-yan; Guo, Rui-chen

    2008-01-01

    A sensitive, simple and selective high-performance liquid chromatography-tandem mass spectrometry method was developed and applied to the determination of norcantharidin concentration in human serum. Norcantharidin (NCTD) and cyclophosphamide (IS) in serum were extracted with acetone, separated on a C18 reversed-phase column, gradiently eluted with a mobile phase of acetonitrile-water containing 2 mm ammonium acetate and 0.1% formic acid (pH 3), ionized by positive ion pneumatically assisted electrospray and detected in the multi-reaction monitoring mode using precursor-->product ions of m/z 169.3-->123.1 for NCTD and 261.2-->140.2 for IS, respectively. The linear range of the calibration curve for NCTD was 2.5-50 ng/mL, with a lowest limit of quantification of 2.5 ng/mL, and the intra/inter-day RSD was less than 10%. The method was suitable for determination of low NCTD concentration in human serum after therapeutic oral doses, and has been successfully used for pharmacokinetic studies in healthy Chinese volunteers.

  7. GC-MS/MS and LC-MS/MS studies on unlabelled and deuterium-labelled oleic acid (C18:1) reactions with peroxynitrite (O=N-O-O⁻) in buffer and hemolysate support the pM/nM-range of nitro-oleic acids in human plasma.

    PubMed

    Trettin, Arne; Böhmer, Anke; Zoerner, Alexander A; Gutzki, Frank-Mathias; Jordan, Jens; Tsikas, Dimitrios

    2014-08-01

    Oleic acid (cis-9,10-octadecenoic acid) is the most abundant monounsaturated fatty acid in human blood. Peroxynitrite (ONOO(-)) is a short-lived species formed from the reaction of nitric oxide (NO) and superoxide (O2(-)). Peroxynitrite is a potent oxidizing and moderate nitrating agent. We investigated reactions of unlabelled and deuterium labelled oleic acid in phosphate buffered saline (PBS) and lysed human erythrocytes with commercially available sodium peroxynitrite (Na(+)ONOO(-)). Non-derivatized reaction products were analyzed by spectrophotometry, HPLC with UV absorbance detection, and LC-MS/MS electrospray ionization in the negative-ion mode. Reaction products were also analyzed by GC-MS/MS in the electron capture negative-ion chemical ionization mode after derivatization first with pentafluorobenzyl (PFB) bromide and then with N,O-bis(trimethylsilyl)trifluoroacetamide. Identified oleic acid reaction products in PBS and hemolysate include cis-9,10-epoxystearic acid and trans-9,10-epoxystearic acid (about 0.1% with respect to oleic acid), threo- and erythro-9,10-dihydroxy-stearic acids. Vinyl nitro-oleic acids, 9-nitro-oleic acid (9-NO2OA) and 10-nitro-oleic acid (10-NO2OA), or other nitro-oleic acids were not found to be formed from the reaction of oleic acid with peroxynitrite in PBS or hemolysate. Our in vitro study suggests that peroxynitrite oxidizes but does not nitrate oleic acid in biological samples. Unlike thiols and tyrosine, oleic acid is not susceptible to peroxynitrite. GC-MS/MS analysis of PFB esters is by far more efficient than LC-MS/MS analysis of non-derivatized oleic acid and its derivates. Our in vitro results support our previous in vivo findings that nitro-oleic acid plasma concentrations of healthy and diseased subjects are in the pM/nM-range.

  8. Characterization of degradation products of idarubicin through LC-UV, MS(n) and LC-MS-TOF studies.

    PubMed

    Kaushik, Dheeraj; Bansal, Gulshan

    2013-11-01

    Idarubicin was subjected to forced degradation under the ICH recommended conditions of hydrolysis, oxidation, dry heat and photolysis to characterize its possible impurities and/or degradation products. The drug was found unstable to acid hydrolysis at 85°C and to alkaline hydrolysis, and oxidation at room temperature. The hydrolytic and oxidative degradation products were resolved with gradient and isocratic elution, respectively on an Inertsil RP18 (250 mm × 4.6mm; 5 μ) column with HCOONH4 (20mM, pH 3.0) and acetonitrile. The drug degraded to two products (O-I and O-II) in oxidative condition, two products (K-I and K-II) in alkaline hydrolytic, and one product (A-I) in acidic hydrolytic conditions. The purity of each in the LC-UV chromatogram was ascertained through LC-PDA analysis. The products were characterized through +ESI-MS(n) studies on the drug and LC-MS-TOF studies on the degraded drug solutions. Based on the multistage mass fragmentation pattern of idarubicin and accurate mass analysis of the degradation products, the O-I, O-II and A-I were characterized as desacetylidarubicin hydroperoxide, desacetylidarubicin and deglucosaminylidarubicin, respectively. The products K-I and K-II were not characterized due to their low concentrations and/or extremely weak ionization. The mechanisms of degradation of idarubicin to these products were proposed and discussed.

  9. Highly sensitive LC-MS/MS method for determination of galantamine in rat plasma: application to pharmacokinetic studies in rats.

    PubMed

    Suresh, P S; Mullangi, Ramesh; Sukumaran, Sathesh Kumar

    2014-12-01

    A rapid and highly sensitive assay method has been developed and validated for the estimation of galantamine (GLM) in rat plasma using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. The assay procedure involves a simple liquid-liquid extraction of GLM and phenacetin (internal standard, IS) from rat plasma using acetonitrile. Chromatographic separation was achieved with 0.2% formic acid:acetonitrile (50:50, v/v) at a flow rate of 0.60 mL/min on an Atlantis dC18 column with a total run time 2.5 min. The MS/MS ion transitions monitored were 288.10 → 213.10 for GLM and 180.10 → 110.10 for IS. Method validation was performed as per United States Food and Drug Administration guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.12 ng/mL and linearity was observed from 0.12 to 525 ng/mL. The intra- and inter-day precision were in the ranges of 4.73-11.7 and 5.83-8.64%, respectively. This novel method has been applied to a pharmacokinetic study in rats.

  10. UPLC-MS/MS determination of phentolamine in human plasma and its application to a pharmacokinetic study.

    PubMed

    Kan, X; Zheng, S-L; Zhou, C-Y

    2014-11-01

    A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine phentolamine in human plasma. Sample preparation was accomplished through a simple liquid-liquid extraction with ethyl acetate. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column using an isocratic mobile phase system composed of acetonitrile and 1% formic acid in water (33:67, v/v) at a flow rate of 0.45 mL/min. Mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 282.1 → 212.0 and m/z 237.1 → 194.2 were used to quantify for phentolamine and carbamazepine (internal standard, IS), respectively. The linearity of this method was found to be within the concentration range of 0.5-100.0 ng/mL with a lower limit of quantification of 0.5 ng/mL. Only 1.0 min was needed for an analytical run. This fully validated method was successfully applied to the pharmacokinetic study after oral administration of 60 mg phentolamine to 20 Chinese healthy male volunteers.

  11. Determination of Sertraline in Human Plasma by UPLC-MS/MS and its Application to a Pharmacokinetic Study.

    PubMed

    Yue, Xiao-Hong; Wang, Zhen; Tian, Dong-Dong; Zhang, Jian-Wei; Zhu, Kang; Ye, Qiang

    2016-02-01

    A sensitive and rapid ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS-MS) method was developed to determine sertraline in human plasma. Sample preparation was accomplished through a simple liquid-liquid extraction with ethyl acetate. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column using a gradient mobile phase system composed of acetonitrile and 1% formic acid in water at a flow rate of 0.40 mL/min. Mass spectrometric analysis was performed using a XEVO TQD mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The multiple reaction monitoring transitions of m/z 306.3 → 275.2 and 326.2 → 291.1 were used to quantify for sertraline and midazolam (internal standard), respectively. The linearity of this method was found to be within the concentration range of 1.0-100.0 ng/mL with a lower limit of quantification of 1.0 ng/mL. Only 2.0 min was needed for an analytical run. This fully validated method was successfully applied to the pharmacokinetic study after an oral administration of 100 mg sertraline to 20 Chinese healthy male volunteers.

  12. LC-MS/MS method for determination of megestrol in human plasma and its application in bioequivalence study.

    PubMed

    Li, Fan; Zou, Xiao-juan; Zheng, Heng; Xiang, Yi

    2013-12-01

    A rapid and highly selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of megestrol in human plasma was described using medrysone as internal standard (IS). Blood samples were collected from 20 healthy volunteers after oral administration of 160 mg megestrol acetate dispersible tablets. The analytes were extracted by liquid-liquid extraction procedure and separated on a hanbon lichrospher column with the mobile phase of methanol and water containing 0.1% formic acid and 20 mmol/L ammonium acetate (5:1, v/v). Positive ion electrospray ionization with multiple reaction-monitoring mode (MRM) was employed by monitoring the transitions m/z 385.5-325.4 and m/z 387.5-327.4 for megestrol and medrysone, respectively. Under the isocratic separation conditions, the chromatographic run time was approximately 2.54 min for megestrol and 2.59 min for medrysone. The calibration curve range was from 0.5 to 200.0 ng/mL. The inter-batch and intra-batch precision and accuracy were less than 5.2% relative standard deviation (RSD) and 6.4% relative error (RE). The proposed method was successfully applied in the bioequivalence study of megestrol acetate dispersible tablets.

  13. Simple and Robust Analysis of Cefuroxime in Human Plasma by LC-MS/MS: Application to a Bioequivalence Study.

    PubMed

    Hu, Xingjiang; Huang, Mingzhu; Liu, Jian; Chen, Junchun; Shentu, Jianzhong

    2014-01-01

    A simple, robust LC-MS/MS assay for quantifying cefuroxime in human plasma was developed. Cefuroxime and tazobactam, as internal standard (IS), were extracted from human plasma by methanol to precipitate protein. Separation was achieved on a Zorbax SB-Aq (4.6 × 250 mm, 5  μ m) column under isocratic conditions. The calibration curve was linear in the concentration range of 0.0525-21.0  μ g/mL (r = 0.9998). The accuracy was higher than 90.92%, while the intra- and interday precision were less than 6.26%. The extraction procedure provides recovery ranged from 89.44% to 92.32%, for both analyte and IS. Finally, the method was successfully applied to a bioequivalence study of a single 500 mg dose of cefuroxime axetil in 22 healthy Chinese male subjects under fasting condition. Bioequivalence was determined by calculating 90% Cls for the ratios of C max, AUC0-t , and AUC0-∞ values for the test and reference products, using logarithmic transformed data. The 90% Cls for the ratios of C max (91.4%~104.2%), AUC0-t (97.4%~110.9%), and AUC0-∞ (97.6%~111.1%) values were within the predetermined range. It was concluded that the two formulations (test for capsule, reference for tablet) analyzed were bioequivalent in terms of rate and extent of absorption and the method met the principle of quick and easy clinical analysis.

  14. An UPLC-MS/MS method for the quantitation of vortioxetine in rat plasma: Application to a pharmacokinetic study.

    PubMed

    Gu, Er-min; Huang, Chengke; Liang, Bingqing; Yuan, Lingjing; Lan, Tian; Hu, Guoxin; Zhou, Hongyu

    2015-08-01

    In this work, a simple, sensitive and fast ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitative determination of vortioxetine in rat plasma. Plasma samples were processed with a protein precipitation. The separation was achieved by an Acquity UPLC BEH C18 column (2.1mm×50mm, 1.7μm) column with a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile. Detection was carried out using positive-ion electrospray tandem mass spectrometry via multiple reaction monitoring (MRM). The validated method had an excellent linearity in the range of 0.05-20ng/mL (R(2)>0.997) with a lower limit of quantification (0.05ng/mL). The extraction recovery was in the range of 78.3-88.4% for vortioxetine and 80.3% for carbamazepine (internal standard, IS). The intra- and inter-day precision was below 8.5% and accuracy was from -11.2% to 9.5%. No notable matrix effect and astaticism was observed for vortioxetine. The method has been successfully applied to a pharmacokinetic study of vortioxetine in rats for the first time, which provides the basis for the further development and application of vortioxetine.

  15. Determination of bergenin in human plasma after oral administration by HPLC-MS/MS method and its pharmacokinetic study.

    PubMed

    Wang, Jin; Wang, Ben-Jie; Wei, Chun-Min; Yuan, Gui-Yan; Zhang, Rui; Liu, Hui; Zhang, Xiu-Mei; Guo, Rui-Chen

    2009-02-01

    A highly sensitive, simple and selective high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and applied to the determination of bergenin concentration in human plasma. Bergenin and the internal standard (IS) thiamphenicol in plasma were extracted with ethyl acetate, separated on a C(18 )reversed-phase column, eluted with mobile phase of acetonitrile-water, ionized by negative ion pneumatically assisted electrospray and detected in the multi-reaction monitoring mode using precursor --> product ions of m/z 327.1 --> 192 for bergenin and 354 --> 185.1 for the IS, respectively. The linear range of the calibration curve for bergenin was 0.25-60 ng mL(-1), with the lowest limit of quantification of 0.25 ng mL(-1), and the intra/inter-day relative standard deviation (RSD) was less than 10%. The method is suitable for the determination of low bergenin concentration in human plasma after therapeutic oral doses, and has been first and successfully used for its pharmacokinetic studies in healthy Chinese volunteers.

  16. Simultaneous determination of amoxicillin and ambroxol in human plasma by LC-MS/MS: validation and application to pharmacokinetic study.

    PubMed

    Wen, Aidong; Hang, Taijun; Chen, Suning; Wang, Zhirui; Ding, Likun; Tian, Yun; Zhang, Meng; Xu, Xinxin

    2008-11-04

    A rapid, simple and sensitive LC-MS/MS method was developed for simultaneous determination of amoxicillin and ambroxol in human plasma using clenbuterol as internal standard (IS). The plasma samples were subjected to a simple protein precipitation with methanol. Separation was achieved on a Lichrospher C(18) column (150 mm x 4.6mm ID, dp 5 microm) using methanol (containing 0.2% of formic acid) and water (containing 0.2% of formic acid) as a mobile phase by gradient elution at a flow rate of 1.0 mL/min. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring (MRM) mode by monitoring the ion transitions from m/z 365.9-->348.9 (amoxicillin), m/z 378.9-->263.6 (ambroxol) and m/z 277.0-->203.0 (IS). Calibration curves were linear in the concentration range of 5-20,000 ng/mL for amoxicillin, and 1-200 ng/mL for ambroxol, with the intra- and inter-run precisions of <9% and the accuracies of 100+/-7%. The method has been validated and applied to pharmacokinetic studies of compound amoxicillin and ambroxol hydrochloride tablets in healthy Chinese volunteers.

  17. Liquid- and gas-phase nitration of bovine serum albumin studied by LC-MS and LC-MS/MS using monolithic columns.

    PubMed

    Walcher, Wolfgang; Franze, Thomas; Weller, Michael G; Pöschl, Ulrich; Huber, Christian G

    2003-01-01

    Post-translational nitration of proteins was analyzed by capillary reversed-phase high-performance liquid chromatography (RP-HPLC) on-line interfaced to electrospray ionization mass spectrometry (ESI--MS) or tandem mass spectrometry (ESI--MS/MS). Both methods were compared using a tryptic digest of bovine serum albumin (BSA) and yielded sequence coverages of 95% and 33% with RP-HPLC--ESI--MS and RP-HPLC--ESI--MS/MS, respectively. At least 95% of the tyrosines were covered by the former method, whereas the latter method only detected less than 50% of the tyrosine-containing peptides. Upon liquid-phase nitration of BSA in aqueous solution using an excess of tetranitromethane, at least 16 of the 20 tyrosine residues were found to be nitrated. After exposure of solid BSA samples to gaseous nitrogen dioxide and ozone at atmospherically relevant concentration levels, only 3 nitrated peptides were detected. By use of such a model system, RP-HPLC--ESI--MS proved to be a rapid and highly efficient method for the comprehensive and quantitative detection of protein nitration.

  18. Studies on the metabolism of the Delta9-tetrahydrocannabinol precursor Delta9-tetrahydrocannabinolic acid A (Delta9-THCA-A) in rat using LC-MS/MS, LC-QTOF MS and GC-MS techniques.

    PubMed

    Jung, Julia; Meyer, Markus R; Maurer, Hans H; Neusüss, Christian; Weinmann, Wolfgang; Auwärter, Volker

    2009-10-01

    In Cannabis sativa, Delta9-Tetrahydrocannabinolic acid-A (Delta9-THCA-A) is the non-psychoactive precursor of Delta9-tetrahydrocannabinol (Delta9-THC). In fresh plant material, about 90% of the total Delta9-THC is available as Delta9-THCA-A. When heated (smoked or baked), Delta9-THCA-A is only partially converted to Delta9-THC and therefore, Delta9-THCA-A can be detected in serum and urine of cannabis consumers. The aim of the presented study was to identify the metabolites of Delta9-THCA-A and to examine particularly whether oral intake of Delta9-THCA-A leads to in vivo formation of Delta9-THC in a rat model. After oral application of pure Delta9-THCA-A to rats (15 mg/kg body mass), urine samples were collected and metabolites were isolated and identified by liquid chromatography-mass spectrometry (LC-MS), liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high resolution LC-MS using time of flight-mass spectrometry (TOF-MS) for accurate mass measurement. For detection of Delta9-THC and its metabolites, urine extracts were analyzed by gas chromatography-mass spectrometry (GC-MS). The identified metabolites show that Delta9-THCA-A undergoes a hydroxylation in position 11 to 11-hydroxy-Delta9-tetrahydrocannabinolic acid-A (11-OH-Delta9-THCA-A), which is further oxidized via the intermediate aldehyde 11-oxo-Delta9-THCA-A to 11-nor-9-carboxy-Delta9-tetrahydrocannabinolic acid-A (Delta9-THCA-A-COOH). Glucuronides of the parent compound and both main metabolites were identified in the rat urine as well. Furthermore, Delta9-THCA-A undergoes hydroxylation in position 8 to 8-alpha- and 8-beta-hydroxy-Delta9-tetrahydrocannabinolic acid-A, respectively, (8alpha-Hydroxy-Delta9-THCA-A and 8beta-Hydroxy-Delta9-THCA-A, respectively) followed by dehydration. Both monohydroxylated metabolites were further oxidized to their bishydroxylated forms. Several glucuronidation conjugates of these metabolites were identified. In vivo conversion of Delta9-THCA-A to Delta9-THC was

  19. Determination of chlorpheniramine in human plasma by HPLC-ESI-MS/MS: application to a dexchlorpheniramine comparative bioavailability study.

    PubMed

    Moreno, Ronilson Agnaldo; Oliveira-Silva, Diogo; Sverdloff, Carlos Eduardo; Borges, Bruno Carter; Rebelo Galvinas, Paulo Alexandre; Astigarraga, Rafael Barrientos; Borges, Ney Carter

    2010-07-01

    In the present study a fast, sensitive and robust validated method to quantify chlorpheniramine in human plasma using brompheniramine as internal standard (IS) is described. The analyte and the IS were extracted from plasma by LLE (diethyl ether-dichloromethane, 80:20, v/v) and analyzed by HPLC-ESI-MS/MS. Chromatographic separation was performed using a gradient of methanol from 35 to 90% with 2.5 mm NH(4)OH on a Gemini Phenomenex C(8) 5 microm column (50 x 4.6 mm i.d.) in 5.0 min/run. The method fitted to a linear calibration curve (0.05-10 ng/mL, R > 0.9991). The precision (%CV) and accuracy ranged, respectively: intra-batch from 1.5 to 6.8% and 99.1 to 106.6%, and inter-batch from 2.4 to 9.0%, and 99.9 to 103.1%. The validated bioanalytical procedure was used to assess the comparative bioavailability in healthy volunteers of two dexchlorpheniramine 2.0 mg tablet formulations (test dexchlorpheniramine, Eurofarma, and reference Celestamine, Schering-Plough). The study was conducted using an open, randomized, two-period crossover design with a 2 week washout interval. Since the 90% confidence interval for C(max) and AUC ratios were all within the 80-125% interval proposed by ANVISA and FDA, it was concluded that test and reference formulations are bioequivalent concerning the rate and the extent of absorption.

  20. An improved LC-MS/MS method for quantitation of indapamide in whole blood: application for a bioequivalence study.

    PubMed

    Pinto, Guilherme Araújo; Pastre, Kátia Isabel Fercondini; Bellorio, Karini Bruno; de Souza Teixeira, Leonardo; de Souza, Weidson Carlo; de Abreu, Fernanda Crunivel; de Santana E Silva Cardoso, Fabiana Fernandes; Pianetti, Gerson Antônio; César, Isabela Costa

    2014-09-01

    An improved LC-MS/MS method for the quantitation of indapamide in human whole blood was developed and validated. Indapamide-d3 was used as internal standard (IS) and liquid-liquid extraction was employed for sample preparation. LC separation was performed on Synergi Polar RP-column (50 × 4.6 mm i.d.; 4 µm) and mobile phase composed of methanol and 5 mm aqueous ammonium acetate containing 1 mm formic acid (60:40), at flow rate of 1 mL/min. The run time was 3.0 min and the injection volume was 20 μL. Mass spectrometric detection was performed using electrospray ion source in negative ionization mode, using the transitions m/z 364.0 → m/z 188.9 and m/z 367.0 → m/z 188.9 for indapamide and IS, respectively. Calibration curve was constructed over the range 0.25-50 ng/mL. The method was precise and accurate, and provided recovery rates >80% for indapamide and IS. The method was applied to determine blood concentrations of indapamide in a bioequivalence study with two sustained release tablet formulations. The 90% confidence interval for the geometric mean ratios for maximum concentration was 95.78% and for the area under the concentration-time curve it was 97.91%. The tested indapamide tablets (Eurofarma Laboratórios S.A.) were bioequivalent to Natrilix®, according to the rate and extent of absorption.

  1. Simultaneous Quantification of Baricitinib and Methotrexate in Rat Plasma by LC-MS/MS: Application to a Pharmacokinetic Study

    PubMed Central

    Veeraraghavan, Sridhar; Thappali, Satheeshmanikandan R. S.; Viswanadha, Srikant; Vakkalanka, Swaroop; Rangaswamy, Manivannan

    2016-01-01

    Efficacy assessments using a combination of baricitinib and methotrexate necessitate the development of an analytical method for the determination of both drugs in plasma with precision. A high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of baricitinib and methotrexate in rat plasma. Extraction of baricitinib, methotrexate, and tolbutamide (internal standard; IS) from 50 µL of rat plasma was carried out by protein precipitation with methanol. Chromatographic separation of the analytes was performed on the YMC pack ODS AM (150 mm × 4.6 mm, 5 µm) column under gradient conditions with methanol: 2.0 mM ammonium acetate buffer as the mobile phases at a flow rate of 1 mL/min. The precursor ion and product ion transition for both analytes and IS were monitored on a triple quadrupole mass spectrometer, operated with selective reaction monitoring in positive ionization mode. The method was validated over a concentration range of 0.5–250.00 ng/mL for baricitinib and methotrexate. Mean extraction recoveries for baricitinib, methotrexate, and IS of 86.8%, 89.4%, and 91.8% were consistent across low, medium, and high QC levels, respectively. Precision and accuracy at low, medium, and high quality control levels were less than 15% across the analytes. Benchtop, wet, freeze-thaw, and long-term stability were evaluated for both of the analytes. The analytical method was applied to support the pharmacokinetic study of simultaneous estimation of baricitinib and methotrexate in Wistar rats. Assay reproducibility was demonstrated by reanalysis of 18 incurred samples PMID:27222609

  2. LC-MS/MS method for the determination of pitolisant: application to rat pharmacokinetic and brain penetration studies.

    PubMed

    Nirogi, Ramakrishna; Ajjala, Devender Reddy; Kandikere, Vishwottam; Pantangi, Hanumanth Rao; Jonnala, Mahesh Reddy; Bhyrapuneni, Gopinadh; Muddana, Nageswar Rao; Vurimindi, Himabindu

    2013-11-01

    A simple and sensitive LC-MS/MS method was developed and validated for the quantitation of pitolisant, an H3 receptor antagonist/inverse agonist. Acetonitrile protein precipitation technique was used to prepare rat blood and brain tissue homogenate samples by using aripiprazole as internal standard (IS). Chromatographic separation was performed by using Xbridge column (2.1 × 50 mm, 3.5 µm) with a gradient elution program. The mobile phase consists of ammonium formate (10 mm) with 0.2% formic acid and acetonitrile. Multiple reaction monitoring mode was used in positive polarity with a transition of m/z 296.3 → 98.2 for the pitolisant and m/z 448.2 → 285.3 for the IS. The calibration curves were linear in the range of 0.1-100 ng/mL in both the blood and brain homogenate samples. This method was applied to quantify samples obtained from the pharmacokinetic and brain penetration studies in male wistar rats. Mean maximum concentration, area under the curve from zero to infinity and half-life of the pitolisant were found to be 3.4 ± 1.7 ng/mL, 5 ± 4 ng h/mL and 1.9 ± 0.3 h, respectively, after a 3 mg/kg oral dose. The mean calculated concentrations in the brain were found to be 38, 60 and 52 ng/g at 0.5, 1 and 2 h, respectively.

  3. Studies on separation and pharmacokinetics of m-nisoldipine enantiomers in beagle dog plasma by LC/MS/MS.

    PubMed

    Li, Min; Yuan, Lin; Li, Xiuqing; Zhi, Xuran; Sheng, Ning; Zhang, Lantong

    2013-11-01

    A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric (LC/MS/MS) method was developed and validated for the separation and determination of m-nisoldipine enantiomers in beagle dog plasma. Samples were pretreated by a single-step protein precipitation with acetonitrile. After m-nisoldipine racemic administration to beagle dogs, samples of m-nisoldipine enantiomers in beagle dog plasma were separated and determined on a ULTRON ES-OVM column (150 × 4.6 mm, 5 μm) at 20°C with a mobile phase consisted of methanol-acetonitrile-ammonium acetate (pH 7.0; 2mM) (15:15:70, v/v/v) at a flow rate of 0.8 mL/min. Chromatograms were monitored at 237 nm, and the API 4000 triple quadrupole mass spectrometer was operated in multiple reaction monitoring (MRM) scan mode using ElectroSpray ionization (ESI) source. The good linearity (rs=0.9958 and rr=0.9983) were found in the range 0.25-20 ng/mL. The lower limit of quantification (LLOQ) obtained was 0.25 ng/mL (n=6). All the validation data, such as accuracy, precision, intra-day and inter-day repeatability, were within the required limits. The method was successfully applied to separation and pharmacokinetics of m-nisoldipine enantiomers in beagle dog plasma. The result of statistics analysis shows that there are no significant differences between R-(-)-m-nisoldipine and S-(+)-m-nisoldipine (p>0.05). The study provides necessary evidences for the research and new drug development of m-nisoldipine enantiomers.

  4. Enantiospecific determination of arotinolol in rat plasma by LC-MS/MS: application to a stereoselective pharmacokinetic study.

    PubMed

    Qian, Zheyuan; Xu, Yanhai; Zheng, Leyi; Zhang, Jingbo; Hong, Zhanying; Shen, Xiaohang

    2015-01-01

    A highly sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated for quantification of arotinolol enantiomers in rat plasma using haloperidol as the internal standard. After solid phase extraction of 50.0 μL rat plasma in 96 well plate, a baseline resolution of arotinolol enantiomers was achieved on a CHIRALPAK AD-H column using the mobile phase of n-hexane and ethanol in 0.02% diethylamine (20:80, v/v) at a flow rate of 0.550 mL/min within 11.0 min. Acquisition of mass spectrometric data was performed on a triple-quadrupole mass spectrometer in multiple-reaction-monitoring (MRM) mode with an ESI source using the transition m/z 372.1 → 316.1 for (±)-arotinolol and m/z 376.1 → 165.1 for haloperidol. The calibration curves of both enantiomers were linear over the range of 1.00-200.0 ng/mL (r(2)>0.992) and the lower limit of quantification was 1.00 ng/mL. Intra- and inter-day precision ranged from 5.6% to 8.9% for R-(-)-arotinolol and 4.6-7.4% for S-(+)-arotinolol. Accuracy varied from 0.0% to 7.0% for R-(-)-arotinolol and 5.0-10.0% for S-(+)-arotinolol. For R-(-)-arotinolol, the recovery ranged from 87.2% to 99.2% and the matrix factor was 1.03-1.09; for S-(+)-arotinolol, the recovery ranged from 88.0% to 92.4% and the matrix factor was 0.84-0.95, both were not concentration dependent. The method was demonstrated with acceptable accuracy, precision and specificity for the determination of arotinolol enantiomers and has been successfully applied to a stereoselective pharmacokinetic study.

  5. Importance of MS selectivity and chromatographic separation in LC-MS/MS-based methods when investigating pharmaceutical metabolites in water. Dipyrone as a case of study.

    PubMed

    Ibáñez, M; Gracia-Lor, E; Sancho, J V; Hernández, F

    2012-08-01

    Pharmaceuticals are emerging contaminants of increasing concern because of their presence in the aquatic environment and potential to reach drinking-water sources. After human and/or veterinary consumption, pharmaceuticals can be excreted in unchanged form, as the parent compound, and/or as free or conjugated metabolites. Determination of most pharmaceuticals and metabolites in the environment is commonly made by liquid chromatography (LC) coupled to mass spectrometry (MS). LC coupled to tandem MS is the technique of choice nowadays in this field. The acquisition of two selected reaction monitoring (SRM) transitions together with the retention time is the most widely accepted criterion for a safe quantification and confirmation assay. However, scarce attention is normally paid to the selectivity of the selected transitions as well as to the chromatographic separation. In this work, the importance of full spectrum acquisition high-resolution MS data using a hybrid quadrupole time-of-flight analyser and/or a suitable chromatographic separation (to reduce the possibility of co-eluting interferences) is highlighted when investigating pharmaceutical metabolites that share common fragment ions. For this purpose, the analytical challenge associated to the determination of metabolites of the widely used analgesic dipyrone (also known as metamizol) in urban wastewater is discussed. Examples are given on the possibilities of reporting false positives of dypirone metabolites by LC-MS/MS under SRM mode due to a wrong assignment of identity of the compounds detected.

  6. A lead isotope distribution study in swine tissue using ICP-MS

    USGS Publications Warehouse

    May, T.W.; Wiedmeyer, Ray H.; Brown, L.D.; Casteel, S.W.

    1999-01-01

    In the United States lead is an ubiquitous environmental pollutant that is a serious human health hazard, especially for women of childbearing age, developing fetuses, and young children. Information concerning the uptake and distribution of lead to maternal and fetal tissues during pregnancy is poorly documented. A study was designed using domestic swine and lead isotope enrichment methodology to focus on maternal absorption and distribution of lead into bone and soft tissues, including the fetal compartment, under varying conditions of oral lead exposure and during altered physiological states (pregnant vs unbred). Total lead levels and Pb207/Pb206 ratios in bone (femur and vertebra), blood, and soft tissues (liver, kidney, brain) were determined by ICP-MS. Lead in fetal tissues derived from maternal bone could be differentiated from that derived from exogenous dosing. Unbred swine absorbed much less lead than pregnant females receiving the same dose. The accuracy and precision of ICP-MS at the instrumental level and for the entire method (sample collection, digestion, and analysis) were evaluated for both Pb207/Pb206 ratios and total lead. Several changes were suggested in method design to improve both instrumental and total method precision.

  7. Effect of occupation on risk of developing MS: an insurance cohort study

    PubMed Central

    Horwitz, Henrik; Ahlgren, Birgitte; Nærum, Elisabeth

    2013-01-01

    Objective The aim of this study was to estimate the occupational risks in relation to multiple sclerosis (MS). The immediate background for this research was our finding that there had been a high number of critical illness insurance claims by patients diagnosed with MS within the agricultural segment of a Danish pension fund. Design An open insurance cohort. All payouts for the critical illness insurance from 2002 to 2011 were continuously registered. Settings PensionDanmark; one of Denmark's largest pension funds. Participants PensionDanmark insures more than 300 000 members of the Danish Confederation of Trade Unions against critical illness. All members are insured, and all policies are identical. The total exposure is 3.3 million person-years. Primary outcome measures The incidence of MS. Results During the 10-year period, 389 persons were diagnosed with MS. The crude incidence rate for men was 10.2/100 000; the corresponding figure for women was 16.1/100 000. We found signs of an overall effect of occupation on the risk of developing MS, and the high frequency found within the agricultural segment was attributed to dairy operators, who had an incidence of MS 2.0 times higher than the rest of the study's population (95% CI=1.2 to 3.0). Conclusions Our results indicate some occupational risk factors in MS, and this should be investigated further. PMID:23794592

  8. Chemical profiling analysis of Maca using UHPLC-ESI-Orbitrap MS coupled with UHPLC-ESI-QqQ MS and the neuroprotective study on its active ingredients.

    PubMed

    Zhou, Yanyan; Li, Peng; Brantner, Adelheid; Wang, Hongjie; Shu, Xinbin; Yang, Jian; Si, Nan; Han, Lingyu; Zhao, Haiyu; Bian, Baolin

    2017-03-17

    Lepidium meyenii (Maca), originated from Peru, has been cultivated widely in China as a popular health care food. However, the chemical and effective studies of Maca were less in-depth, which restricted its application seriously. To ensure the quality of Maca, a feasible and accurate strategy was established. One hundred and sixty compounds including 30 reference standards were identified in 6 fractions of methanol extract of Maca by UHPLC-ESI-Orbitrap MS. Among them, 15 representative active compounds were simultaneously determined in 17 samples by UHPLC-ESI-QqQ MS. The results suggested that Maca from Yunnan province was the potential substitute for the one from Peru. Meanwhile, the neuroprotective effects of Maca were investigated. Three fractions and two pure compounds showed strong activities in the 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced zebrafish model. Among them, 80% methanol elution fraction (Fr5) showed significant neuroprotective activity, followed by 100% part (Fr6). The inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was a possible mechanism of its neuroprotective effect.

  9. Chemical profiling analysis of Maca using UHPLC-ESI-Orbitrap MS coupled with UHPLC-ESI-QqQ MS and the neuroprotective study on its active ingredients

    NASA Astrophysics Data System (ADS)

    Zhou, Yanyan; Li, Peng; Brantner, Adelheid; Wang, Hongjie; Shu, Xinbin; Yang, Jian; Si, Nan; Han, Lingyu; Zhao, Haiyu; Bian, Baolin

    2017-03-01

    Lepidium meyenii (Maca), originated from Peru, has been cultivated widely in China as a popular health care food. However, the chemical and effective studies of Maca were less in-depth, which restricted its application seriously. To ensure the quality of Maca, a feasible and accurate strategy was established. One hundred and sixty compounds including 30 reference standards were identified in 6 fractions of methanol extract of Maca by UHPLC-ESI-Orbitrap MS. Among them, 15 representative active compounds were simultaneously determined in 17 samples by UHPLC-ESI-QqQ MS. The results suggested that Maca from Yunnan province was the potential substitute for the one from Peru. Meanwhile, the neuroprotective effects of Maca were investigated. Three fractions and two pure compounds showed strong activities in the 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced zebrafish model. Among them, 80% methanol elution fraction (Fr5) showed significant neuroprotective activity, followed by 100% part (Fr6). The inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was a possible mechanism of its neuroprotective effect.

  10. Chemical profiling analysis of Maca using UHPLC-ESI-Orbitrap MS coupled with UHPLC-ESI-QqQ MS and the neuroprotective study on its active ingredients

    PubMed Central

    Zhou, Yanyan; Li, Peng; Brantner, Adelheid; Wang, Hongjie; Shu, Xinbin; Yang, Jian; Si, Nan; Han, Lingyu; Zhao, Haiyu; Bian, Baolin

    2017-01-01

    Lepidium meyenii (Maca), originated from Peru, has been cultivated widely in China as a popular health care food. However, the chemical and effective studies of Maca were less in-depth, which restricted its application seriously. To ensure the quality of Maca, a feasible and accurate strategy was established. One hundred and sixty compounds including 30 reference standards were identified in 6 fractions of methanol extract of Maca by UHPLC-ESI-Orbitrap MS. Among them, 15 representative active compounds were simultaneously determined in 17 samples by UHPLC-ESI-QqQ MS. The results suggested that Maca from Yunnan province was the potential substitute for the one from Peru. Meanwhile, the neuroprotective effects of Maca were investigated. Three fractions and two pure compounds showed strong activities in the 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced zebrafish model. Among them, 80% methanol elution fraction (Fr5) showed significant neuroprotective activity, followed by 100% part (Fr6). The inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was a possible mechanism of its neuroprotective effect. PMID:28304399

  11. Simultaneous determination of erlotinib and tamoxifen in rat plasma using UPLC-MS/MS: Application to pharmacokinetic interaction studies.

    PubMed

    Maher, Hadir M; Alzoman, Nourah Z; Shehata, Shereen M

    2016-08-15

    Tamoxifen (TAM) is a non-steroidal estrogen receptor antagonist that enhances erlotinib (ERL)-induced cytotoxicity in the treatment of NSCLC. ERL and TAM are metabolized by CYP3A4 enzymes. In addition, both drugs have the potential of altering the enzymatic activity through either inhibition (ERL) or induction (TAM). Thus it was expected that pharmacokinetics (PK) drug-drug interactions (DDIs) could be encountered following their co-administration. In this respect, a bioanalytical UPLC-MS/MS method has been developed and validated for the simultaneous determination of ERL and TAM in rat plasma samples, using ondansetron (OND) as an internal standard (IS). Plasma samples were prepared using mixed mode cationic solid phase extraction (SPE) STRATA™ -X-C 33μm cartridges with good extraction recovery of both drugs from rat plasma (Er% from -13.92 to -3.32). The drugs were separated on a Waters BEH™ C18 column with an isocratic elution using a mobile phase composed of a mixture of acetonitrile and water, each with 0.15% formic acid, in the ratio of 80: 20, v/v. Quantitation was carried out using the positive ionization mode with multiple reaction monitoring (MRM) at m/z 394.20>278.04 (ERL), m/z 372.25>72.01 (TAM), and m/z 294.18>170.16 (OND). The method was fully validated as per the FDA guidelines over the concentration range of 0.2-50ng/mL with very low lower limit of quantification (LLOQ) of 0.2ng/mL for both ERL and TAM. The intra- and inter-day assay precision (in terms of relative standard deviation, RSD) and accuracy (in terms of percentage relative error, % Er) were evaluated for both drugs and the calculated values evaluated at four different concentration levels were within the acceptable limits (<15%) for concentrations other than LLOQ and 20% for LLOQ. The method was successfully applied to the study of possible PK-DDI following the oral administration of ERL and TAM in a combination, compared to their single administration.

  12. Chemical redox reactions in ES-MS: Study of electrode reactions

    SciTech Connect

    Zhou, Feimeng; VAn Berkel, G.J.

    1995-12-31

    The authors previously demonstrated that chemical redox reactions can be used to ionize neutral commpounds for electrospray mass spectrometric (ES-MS) detection. Two different compounds, viz, C{sub 60}F{sub 48} and {beta}-carotene were used to demonstrate the utility of chemical redox reactions with on-line ES-MS for the elucidation of mechanisms of complicated electron transfer reactions and for the kinetic study of electrode reactions in which relatively short-lived intermediates are involved.

  13. A bioequivalency study of two trifluoperazine tablet formulations using RIA and GC-MS.

    PubMed

    Midha, K K; Hawes, E M; Korchinski, E D; Hubbard, J W; McKay, G; Cooper, J K; Roscoe, R M

    1984-01-01

    Two sensitive analytical procedures, a radioimmunoassay (RIA) and a mass fragmentographic (GC-MS) method, were used to quantitate plasma trifluoperazine concentrations over 24 h in five healthy male volunteers following single 5 mg doses of two trifluoperazine tablet formulations (A and B) in a two-way cross-over design. Bioavailability in terms of area under the plasma concentration versus time curve to 24h or extrapolated to infinity, maximum plasma concentration and time to maximum plasma concentration using either RIA or GC-MS was not statistically significantly different from one formulation to the other. Also, there were no statistically significant differences between GC-MS and RIA values for AUC24(0) and Cmax for each of the two formulations examined. However, the mean AUC24(0) RIA/GC-MS ratios for formulations A and B were 3.1 and 3.4, respectively, while the mean Cmax RIA/GC-MS ratios were 1.7 and 2.1, respectively. These differences in AUC and Cmax are probably mainly due to the relative non-specificity of the RIA antiserum. Thus, where GC-MS is preferred for pharmacokinetic studies, both analytical procedures can be used for comparative single-dose bioequivalence studies of trifluoperazine. However, both the methods should be tested in patients in order to establish the suitability of one procedure over the other for the study of plasma level versus clinical response correlations.

  14. A mixed-effects Statistical Model for Comparative LC-MS Proteomics Studies

    SciTech Connect

    Daly, Don S.; Anderson, Kevin K.; Panisko, Ellen A.; Purvine, Samuel O.; Fang, Ruihua; Monroe, Matthew E.; Baker, Scott E.

    2008-03-01

    Comparing a protein’s concentrations across two or more treatments is the focus of many proteomics studies. A frequent source of measurements for these comparisons is a mass spectrometry (MS) analysis of a protein’s peptide ions separated by liquid chromatography (LC) following its enzymatic digestion. Alas, LC-MS identification and quantification of equimolar peptides can vary significantly due to their unequal digestion, separation and ionization. This unequal measurability of peptides, the largest source of LC-MS nuisance variation, stymies confident comparison of a protein’s concentration across treatments. Our objective is to introduce a mixed-effects statistical model for comparative LC-MS proteomics studies. We describe LC-MS peptide abundance with a linear model featuring pivotal terms that account for unequal peptide LC-MS measurability. We advance fitting this model to an often incomplete LC-MS dataset with REstricted Maximum Likelihood (REML) estimation, producing estimates of model goodness-offit, treatment effects, standard errors, confidence intervals, and protein relative concentrations. We illustrate the model with an experiment featuring a known dilution series of a filamentous ascomycete fungus Trichoderma reesei protein mixture. For the 781 of 1546 T.reesei proteins with sufficient data coverage, the fitted mixed-effects models capably described the LC-MS measurements. The LC-MS measurability terms effectively accounted for this major source of uncertainty. Ninety percent of the relative concentration estimates were within 1/2 fold of the true relative concentrations. Akin to the common ratio method, this model also produced biased estimates, albeit less biased. Bias decreased significantly, both absolutely and relative to the ratio method, as the number of observed peptides per protein increased. Mixed-effects statistical modeling offers a flexible, well-established methodology for comparative proteomics studies integrating common

  15. Brain Functional Connectivity in MS: An EEG-NIRS Study

    DTIC Science & Technology

    2015-10-01

    will be available as we proceed and publish on the technological aspects of the work. Inventions, patent applications, and/or licenses Dr. Diamond ...is the inventor on one patent and one patent application for technology that is being used in this study: 1. Diamond , S.G. System, Optode and...Cap for Near-Infrared Diffuse-Optical Functional Neuroimaging. PCT/US09/41560 filed April 23, 2009, issued Sept. 23, 2013. 2. Diamond , S.G. and

  16. Laser ionization/MS study of smog formation

    SciTech Connect

    Hewitt, A.D.; Lee, C.M.; Quimpo, B.C.

    1995-12-01

    Resonance-enhanced multiphoton ionization/time-of-flight mass spectrometry (REMPI/TOFMS) is a highly sensitive and selective technique which we are using to study atmospheric chemistry kinetics and reaction mechanisms. We are presently focusing our attention on toluene, the most abundant of the aromatic hydrocarbons in the troposphere, in order to understand the oxidation pathways which lead to smog formation. Our most recent results monitoring toluene and products of the OH + toluene reaction will be discussed, as well as our future plans to detect short-lived reaction intermediates, such as the methylhydroxycyclohexadienyl radical, formed by the addition of OH to the aromatic ring of toluene.

  17. A new quantitation method of protodioscin by HPLC–ESI-MS/MS in rat plasma and its application to the pharmacokinetic study

    PubMed Central

    Zhang, Xinxin; Guo, Zengjun; Li, Jing; Ito, Yoichiro; Sun, Wenji

    2016-01-01

    A specific high performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS method) was established for determining the concentration of protodioscin (PG) in rat plasma after intragastric administration of its standard form. Ginsenoside Rb1 was selected as the internal standard (IS). The plasma sample was prepared using one-step deproteinization procedure by adding three parts of acetonitrile to precipitate proteins. The chromatographic separation was accomplished on an Inersil ODS-3 C18 column (250 × 4.6 mm, 5 μm) with a mobile phase composed with acetonitrile and water containing 0.1% formic acid under a gradient elution mode at a flow rate of 1 mL min−1. A 3:1 portion of the eluent after a microsplit was detected on a triple quadrupole tandem mass spectrometer coupled with electrospray ionization (ESI) in positive ion and multiple reaction monitoring (MRM) scanning modes. The mass transitions were selected as 888.1 → 1050.2 for PG and 948.2 → 1110.3 for IS, respectively. After careful validation, the plasma samples were always stable under different storage conditions. These analytical results rendered sensitive, selective, and reliable values by this established method which displayed high accuracy, adequate extracted recoveries, and almost negligible matrix effects. This method was applied to the pharmacokinetic studies on PG level in the rat plasma and its pharmacokinetic effect. The results of our studies suggest that the present method may be a useful tool for further clinical study of PG. PMID:26703445

  18. Pragmatic Development of Chinese EFL Learners--A Study on FL Suggestions

    ERIC Educational Resources Information Center

    Gu, Tongqing

    2014-01-01

    While the number of studies on the pragmatic development of nonnative English speakers has been increasing, surprisingly little research has been conducted on the development of the ability of foreign language learners to perform the suggestion speech act, with even less taking Chinese EFL learners as the target group. The present study examines…

  19. Validated LC-MS/MS method for quantification of gabapentin in human plasma: application to pharmacokinetic and bioequivalence studies in Korean volunteers.

    PubMed

    Park, Jin-Hee; Jhee, Ok-Hwa; Park, Song-Hee; Lee, Jung-Sik; Lee, Min-Ho; Shaw, Leslie M; Kim, Kwang-Hyun; Lee, Jong-Ho; Kim, Yong-Seok; Kang, Ju-Seop

    2007-08-01

    A sensitive validated liquid chromatography-tandem mass spectrometric method (LC-MS/MS) for gabapentin (GB) in human plasma has been developed and applied to pharmacokinetic (PK) and bioequivalence (BE) studies in human. In a randomized crossover design with a 1-week period, each subject received a 300 mg GB capsule. The procedure involves a simple protein precipitation with acetonitrile and separated by LC with a Gemini C(18) column using acetonitrile-10 mm ammonium acetate (20:80, v/v, pH 3.2) as mobile phase. The GB and internal standard [(S)-(+)-alpha-aminocyclohexanepropionic acid hydrate] were analyzed using an LC-API 2000 MS/MS in multiple reaction monitoring mode. The ionization was optimized using ESI(+) and selectivity was achieved using MS/MS analysis, m/z 172.0 --> 154.0 and m/z 172.0 --> 126.0 for GB and IS, respectively. The assay exhibited good linearity over a working range of 20-5000 ng/mL for GB in human plasma with a lower limit of quantitation of 20 ng/mL. No endogenous compounds were found to interfere with the analysis. The accuracy and precision were shown for concentrations over the standard ranges. This method was successfully applied for the PK and BE studies by analysis of blood samples taken up to 36 h after an oral dose of 300 mg of GB in 24 healthy volunteers.

  20. Simultaneous quantification method for comparative pharmacokinetics studies of two major metabolites from geniposide and genipin by online mircrodialysis-UPLC-MS/MS.

    PubMed

    Zhang, Xueju; Liu, Shu; Pi, Zifeng; Liu, Zhiqiang; Song, Fengrui

    2017-01-15

    Genipin-1-o-glucuronic acid and genipin-monosulfate are two major metabolites from geniposide and genipin. Based on diabetic rat model, we developed a simultaneous quantification method to investigate their comparative pharmacokinetics by online mircrodialysis-ultra performance liquid chromatography-mass spectrometry (MD-UPLC-MS/MS) without their standard compounds. Online microdialysis sampling could avoid unexpected contamination or degradation of the analytes during the storage and transfer steps. Combined with good sensitivity, selectivity and selectivity of UPLC-MS/MS, online MD-UPLC-MS/MS method could real-timely monitor metabolites in rat blood for quantitative analysis. Our research found that AUC0→t of genipin-1-o-glucuronic acid and genipin-monosulfate in blood of diabetic group were 17.68 and 7.58 times than those in normal group, respectively, and AUC0→t of genipin-1-o-glucuronic acid was 2.28 times than that of genipin-monosulfate in blood of diabetic group, which revealed the effect of diabetes on the pharmacokinetic properties of the two metabolites. This study not only provides an approach for pharmacokinetic studies for various metabolites from herb medicines, but also can predict druggability of their bioactive metabolites. The insight obtained should facilitate drug development and toxicity research.

  1. Tissue distribution study of salvianolic acid B long-circulating liposomes in mice by UPLC-MS/MS determination.

    PubMed

    Pi, Jiaxin; Liu, Zhidong; Shu, Lexin; Li, Lin; Wang, Ying; Li, Nan; Li, Jiawei

    2015-01-01

    In targeting delivery system research on salvianolic acid B, it's vital but hard to evaluate the tissue distribution for its low concentrations in tissues. So the simple, rapid, selective and sensitive UPLC-MS/MS method was provided hereby to determine the concentration of salvianolic acid B in mice tissues after intravenous administration of salvianolic acid B injections, conventional liposomes and long-circulating liposomes. The UPLC was conducted by a C(18) column with a gradient mobile phase consisting of acetonitrile and water containing 0.1% formic acid. The tandem mass spectrometry was operated in negative-electrospray ionization selected-reaction-monitoring mode, and the optimized characteristic precursor to product ion transition m/z 717.3→519.1 was selected. The biosamples were homogenized and treated with a protein precipitation, which led to an acceptable matrix effect and extraction recovery. The linear calibration curves were plotted in the given concentration ranges. The intra-day and inter-day precisions were less than 13.9% and the accuracies were in the range of 86.3-109.2%. The tissue distribution results determined by UPLC-MS/MS we developed showed that the conventional and long-circulating liposomes we made had succeeded in prolonging the retention time and increasing the level of salvianolic acid B in certain distribution tissues such as liver, kidney and brain.

  2. Determination of tegaserod by LC-ESI-MS/MS and its application to a pharmacokinetic study in healthy Chinese volunteers.

    PubMed

    Zou, Jian-Jun; Bian, Xiao-Jie; Ding, Li; Zhu, Yu-Bin; Fan, Hong-Wei; Xiao, Da-Wei

    2008-01-01

    A simple, rapid and sensitive high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) assay for determination of tegaserod in human plasma using diazepam as internal standard (IS) was established. After adjustment to a basic pH with sodium hydroxide, plasma was extracted by ethyl acetate and separated by high performance liquid chromatography (HPLC) on a reversed-phase C18 column with a mobile phase of methanol: 5 mM ammonium acetate (75:25, v/v, adjusting the pH to 3.5 with glacial acetic acid). The quantification of target compounds was obtained by using multiple reaction monitoring (MRM) transitions; m/z 302.5, 173.2 and 285.4, 193.2 were measured in positive mode for tegaserod and internal standard (diazepam), respectively. The lower limit of quantification (LLOQ) was 0.05 ng/ml. The calibration curves were linear over the range 0.05-8.0 ng/ml (r=0.9996) for tegaserod. The mean absolute recovery of tegaserod was more than 85.56%. Intra- and inter-day variability values were less than 9.21% and 10.02%, respectively. The samples were stable for 8h under room temperature (25 degrees C, three freeze-thaw cycles in 30 days and for 30 days under -70 degrees C). After administration of a single dose of tegaserod maleate 4 mg, 6 mg and 12 mg, respectively, the area under the plasma concentration versus time curve from time 0 h to 12 h (AUC0-12) were (2.89+/-0.88), (5.32+/-1.21) and (9.38+/-3.42) ng h/ml, respectively; peak plasma concentration (Cmax) were (1.25+/-0.53), (2.21+/-0.52) and (4.34+/-1.66) ng/ml, respectively; apparent volume of distribution (Vd/F) were (6630.5+/-2057.8), (7615.2+/-2242.8) and (7163.7+/-2057.2) l, respectively; clearance rate (CL/F) were (1851.4+/-496.9), (1596.2+/-378.5) and (1894.2+/-459.3) l/h, respectively; time to Cmax (Tmax) were (1.00+/-0.21), (1.05+/-0.28) and (1.04+/-0.16) h, respectively; and elimination half-life (t1/2) were (3.11+/-0.78), (3.93+/-0.92) and (3.47+/-0.53) h

  3. LC-MS/MS Determination and Pharmacokinetic Study of Pedunculoside in Rat Plasma after Oral Administration of Pedunculoside and Ilex rotunda Extract.

    PubMed

    Zhao, Waiou; Pang, Li; Xu, Dahai; Zhang, Nan

    2015-05-19

    Ilex rotunda is widely used to treat many disorders as a traditional Chinese medicine (TCM) containing 4%-5% pedunculoside (PDC). A rapid, selective, and sensitive liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed and validated to determine PDC in rat plasma by using 3β,19α-dihydroxyurs-12-en-28-oic acid 28-β-D-glucopyranosyl ester (DEOG) as an internal standard. The analytes were extracted by protein precipitation and eluted on a C18 chromatography column using a mobile phase of methanol-H2O (70:30, v/v) delivered at a flow rate of 0.6 mL/min. Detection was performed using positive ion electrospray ionization in multiple reaction monitoring modes. The assay was linear over the concentration range of 0.60 ng/mL to 200 ng/mL, with a quantification limit of 0.60 ng/mL. Intra-day and inter-day precisions (%RSD) ranged from 2.12 to 9.51 for PDC, whereas the accuracy was within -7.83%~9.40%. The validated method was successfully applied to the pharmacokinetic study of PDC in rat plasma after oral administration of pure PDC and Ilex rotunda extract (IRE). Pharmacokinetic parameters of PDC in IRE, such as Cmax, AUC0-t, AUC0-∞, t1/2z, and CLz/F, statistically differed from those of the pure monomer (p < 0.01). However, Tmax and MRT showed no significant differences between the two groups. Results suggested that other coexisting components in IRE may decrease the absorption of PDC. Compound-compound interactions between PDC and other herbal extract components can alter the pharmacokinetic behavior of PDC. The study will be helpful in providing references for understanding the action mechanism and clinical application of Ilex rotunda.

  4. A direct LC/MS/MS method for the determination of ciclopirox penetration across human nail plate in in vitro penetration studies.

    PubMed

    Bu, Wei; Fan, Xiaoqing; Sexton, Holly; Heyman, Irwin

    2010-01-05

    Due to severe chelating effect caused by N-hydroxylpyridone group of ciclopirox, there is no published direct HPLC or LC/MS/MS method for the determination of ciclopirox in any in vitro or in vivo matrix. Instead, the time-consuming pre-column derivatization methods have been adapted for indirect analysis of ciclopirox. After overcoming the chelating problem by using K(2)EDTA coated tubes, a direct, sensitive and high-throughput LC/MS/MS method was successfully developed and validated to determine the amount of ciclopirox that penetrated across the nail plate during in vitro nail penetration studies. The method involved adding a chemical analog, chloridazon as internal standard (IS) in K(2)EDTA coated tubes, mixing IS with ciclopirox in a 96-well plate and then proceeding to LC/MS/MS analysis. The MS/MS was selected to monitor m/z 208.0-->135.8 and 221.8-->77.0 for ciclopirox and IS, respectively, using positive electrospray ionization. The method was validated over a concentration range of 8-256 ng/mL, yielding calibration curves with correlation coefficients greater than 0.9991 with a lower limit of quantitation (LLOQ) of 8 ng/mL. The assay precision and accuracy were evaluated using quality control (QC) samples at three concentration levels. Analyzed concentrations ranged from 101% to 113% of their respective nominal concentration levels with coefficients of variation (CV) below 10.6%. The average recovery of ciclopirox from nail matrix was 101%. The validated method was successfully used to analyze the ciclopirox formulation and in vitro nail penetration samples.

  5. Application of ESI/MS, CID/MS and tandem MS/MS to the fragmentation study of eriodictyol 7-O-glucosyl-(1-->2)-glucoside and luteolin 7-O-glucosyl-(1-->2)-glucoside

    NASA Astrophysics Data System (ADS)

    Es-Safi, Nour-Eddine; Kerhoas, Lucien; Einhorn, Jacques; Ducrot, Paul-Henri

    2005-12-01

    A mass spectrometric method based on the combined use of positive and negative electrospray ionization, collision-induced dissociation and tandem mass spectrometry has been applied to the structural characterization of the eriodictyol 7-O-glucosyl-(1-->2)-glucoside and luteolin 7-O-glucosyl-(1-->2)-glucoside. The low-energy product ion mass spectrum of [M + H]+ and [M - H]- ions showed extensive fragmentation of the diglucose moiety, loss of the glycan residue, and fragmentation of the aglycon units that permit characterization of the interglycosidic linkage and the substituents in the A- and B-rings. Both glycosides were shown to yield the 0,2X00,2X1 ion which can be considered as characteristic of the 1-->2 interglycosidic linkage in the glucoglucoside adducts, since it can not be formed in the case of other interglycosidic types. In the case of the eriodictyol diglucoside the 1, 3 fragmentation of the C-ring was observed before those involving the carbohydrates thus allowing the position determination of the diglucoside moiety on the A-ring. In the negative ion mode only the luteolin diglucoside was shown to undergo collision-induced homolytic and heterolytic cleavages of the O-glycosidic bond producing the aglycone radical-anion [Y0-H]-- and Y0- product ions, while this was not observed in the case of eriodictyol glycoside. CID MS/MS analysis of the sodiated molecules gave complementary informations for the structural characterization of the studied compounds. The B2+ fragment which is useful for establishing that the terminal carbohydrate unit is linked to another carbohydrate and not directly to the aglycone was obtained as base peak. This result is of analytical value for the differentiation of O-diglycosyl and di-O-glycosyl flavonoids.

  6. A GC-MS metabolic profiling study of plasma samples from mice on low- and high-fat diets.

    PubMed

    Spagou, Konstantina; Theodoridis, Georgios; Wilson, Ian; Raikos, Nikolaos; Greaves, Peter; Edwards, Richard; Nolan, Barbara; Klapa, Maria I

    2011-05-15

    Metabolic profiling of biofluids, based on the quantitative analysis of the concentration profile of their free low molecular mass metabolites, has been playing increasing role employed as a means to gain understanding of the progression of metabolic disorders, including obesity. Chromatographic methods coupled with mass spectrometry have been established as a strategy for metabolic profiling. Among these, GC-MS, targeting mainly the primary metabolism intermediates, offers high sensitivity, good peak resolution and extensive databases. However, the derivatization step required for many involatile metabolites necessitates specific data validation, normalization and analysis protocols to ensure accurate and reproducible performance. In this study, the GC-MS metabolic profiles of plasma samples from mice maintained on 12- or 15-month long low (10 kcal%) or high (60 kcal%) fat diets were obtained. The profiles of the trimethylsilyl(TMS)-methoxime(MeOx) derivatives of the free polar metabolites were acquired through GC-(ion trap)MS, using [U-(13)C]-glucose as the internal standard. After the application of a recently developed data correction and normalization/filtering protocol for GC-MS metabolomic datasets, the profiles of 48 out of the 77 detected metabolites were used in multivariate statistical analysis. Data mining suggested a decrease in the activity of the energy metabolism with age. In addition, the metabolic profiles indicated the presence of subpopulations with different physiology within the high- and low-fat diet mice, which correlated well with the difference in body weight among the animals and current knowledge about hyperglycemic conditions.

  7. Analysis of pentacyclic triterpenes by LC-MS. A comparative study between APCI and APPI.

    PubMed

    Rhourri-Frih, B; Chaimbault, P; Claude, B; Lamy, C; André, P; Lafosse, M

    2009-01-01

    The analytical performances of three atmospheric-pressure sources, electrospray (ESI), atmospheric-pressure chemical ionization (APCI), and atmospheric-pressure photoionization (APPI), were evaluated for the analysis of pentacyclic triterpenes in liquid chromatography-mass spectrometry (LC-MS). Among these sources, APPI and APCI are particularly well adapted to sensitive analyses of pentacyclic triterpenes by LC-MS. Detection parameters were optimized for both the sources, and the effects of three dopants (toluene, acetone and anisole) on the detection (sensitivity and ion fingerprints in MS spectra) were studied in detail for APPI-MS.The limits of quantification were measured under selected ion monitoring conditions, in the range of 0.005-0.015 mg l(-1) and 0.002-0.84 mg l(-1) in APPI and APCI, respectively, depending on the studied pentacyclic triterpene. Overall, APPI was found more sensitive than APCI in positive ion mode, whereas APCI shows the greatest sensitivity for acidic triterpenes in negative ion mode.Following this study, the developed LC-MS method was used for the characterization of pentacyclic triterpenes in three plant extracts. High amounts of betulinic acid, betulinic aldehyde and betulinic aldehyde acetate were observed in plane bark. The main component of birch bark is betulin and extracts of okoume resin exhibit high amounts of alpha- and beta-amyrin.

  8. A Visit to a Pig "Hatchery" on the Farm. (A Suggested Unit of Study).

    ERIC Educational Resources Information Center

    Ediger, Marlow

    Objectives for students are provided in this unit of study which suggests diverse learning that can take place in conjunction with a class field trip to a farm specializing in the raising of pigs. Following a brief description of specialization in United States livestock production, the unit lists factual information to be learned, e.g.,…

  9. Study of exhaled breath condensate sample preparation for metabolomics analysis by LC-MS/MS in high resolution mode.

    PubMed

    Fernández-Peralbo, M A; Calderón Santiago, M; Priego-Capote, F; Luque de Castro, M D

    2015-11-01

    Metabolomic analysis of exhaled breath condensate (EBC) requires an unavoidable sample preparation step because of the low concentration of its components, and potential cleanup for possible interferents. Sample preparation based on protein precipitation (PP), solid-phase extraction (SPE) by hydrophilic and lipophilic sorbents or lyophilization has demonstrated that the analytical sample from the last is largely the best because lyophilization allows reconstitution in a volume as small as required (preconcentration factors up to 80-times with respect to the original sample), thus doubling the number of detected compounds as compared with the other alternatives (47 versus 25). In addition, PP and/or SPE cleanup are unnecessary as no effect from the EBC components removed by these steps appears in the chromatograms. The total 49 EBC compounds tentatively identified and confirmed by MS/MS in this research include amino acids, fatty acids, fatty amides, fatty aldehydes, sphingoid bases, oxoanionic compounds, imidazoles, hydroxy acids and aliphatic acyclic acids.

  10. Simultaneous quantification of vortioxetine, carvedilol and its active metabolite 4-hydroxyphenyl carvedilol in rat plasma by UPLC-MS/MS: Application to their pharmacokinetic interaction study.

    PubMed

    Huang, Yi; Zheng, Shuangli; Pan, Yongyang; Li, Tao; Xu, Zhi-Sheng; Shao, Meng-Meng

    2016-09-05

    To establish a rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the determination of vortioxetine, carvedilol and its metabolite 4-hydroxyphenyl carvedilol in rat plasma. The analytes and the internal standard (diazepam) were separated on an Acquity UPLC BEH C18 chromatography column (2.1mm×50mm, 1.7μm) using gradient elution with a mobile phase of acetonitrile and 0.1% formic acid in water at a flow rate of 0.4mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 299.2→150.1 for vortioxetine, m/z 407.2→100.3 for carvedilol, m/z 423.2→100.1 for 4-hydroxyphenyl carvedilol and m/z 285.2→193.1 for diazepam (IS) using a positive electrospray ionization interface. The method was validated over a concentration range of 0.5-100ng/mL for vortioxetine, 0.5-1000ng/mL for carvedilol and 0.1-50ng/mL for 4-hydroxyphenyl carvedilol. Total time for each chromatograph was 3.0min. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels exhibited relative standard deviations (RSD)<11.6% and the accuracy values ranged from -12.2% to 11.3%. The analytical method was successfully applied to a pharmacokinetic interaction study of vortioxetine and carvedilol after oral administration vortioxetine and carvedilol in rats. Results suggested that the co-administration of vortioxetine and carvedilol results in a significant drug interaction in rats.

  11. Enzyme-immobilized reactors for rapid and efficient sample preparation in MS-based proteomic studies.

    PubMed

    Yamaguchi, Hiroshi; Miyazaki, Masaya

    2013-02-01

    Proteolysis is a key step in proteomic studies integrated with MS analysis but the conventional method of in-solution digestion is limited by time-consuming procedures and low sensitivity. Furthermore, obtaining reliable peptide maps and meaningful sequence data using MS analysis requires not only the separation of the digested peptides but also strictly defined proteolysis conditions. Recently, various immobilized-enzyme reactors have been developed for highly efficient proteolysis in MS-based proteomic analysis. This review focuses on the proteolysis step using protease-immobilized reactors and rapid analysis of protein sequences. We describe the preparation of enzyme reactors by several techniques and protein digestion under unusual conditions. Analysis of posttranslational modifications by enzyme reactors prepared using our immobilization method is presented as a model application. Analysis systems using immobilized-enzyme reactors are expected to become useful tools for proteomic studies and diverse applications in biotechnology.

  12. Radiofrequency field exposure and cancer: what do the laboratory studies suggest?

    PubMed Central

    Repacholi, M H

    1997-01-01

    Significant concern has been raised about possible health effects from exposure to radiofrequency (RF) electromagnetic fields, especially after the rapid introduction of mobile telecommunications systems. Parents are especially concerned with the possibility that children might develop cancer after exposure to the RF emissions from mobile telephone base stations erected in or near schools. These questions have followed scientific reports suggesting that residence near high voltage power lines may to be associated with an increased childhood leukemia risk. Epidemiologic studies have been plagued by poor RF exposure assessment and differences in methodology. There are no high-quality epidemiologic studies that can be used to evaluate health risks from RF exposure. Laboratory studies in this area have been somewhat confusing. Some animal studies suggest that RF fields accelerate the development of sarcoma colonies in the lung, mammary tumors, skin tumors, hepatomas, and sarcomas. A substantial RF-induced increase in lymphoma incidence in transgenic mice exposed for up to 18 months has also been reported. In contrast, other studies have not found carcinogenic effects. These conflicting results indicate the need for more well-conducted studies on laboratory animals, supplemented with high-quality in vitro studies to identify effects that need further research in vivo, and to characterize any acting mechanisms, especially at low RF field levels. This paper provides a review of the laboratory studies and indicates what conclusions about RF-induced cancer can be drawn. PMID:9467083

  13. Preliminary study of urine metabolism in type two diabetic patients based on GC-MS

    PubMed Central

    Zhang, Ning; Geng, Fang; Hu, Zhong-Hua; Liu, Bin; Wang, Ye-Qiu; Liu, Jun-Cen; Qi, Yong-Hua; Li, Li-Jing

    2016-01-01

    Objective: Comparative study of type 2 diabetes and healthy controls by metabolomics methods to explore the pathogenesis of Type II diabetes. Methods: Gas chromatography - mass spectrometry (GC-MS) with a variety of multivariate statistical analysis methods to the healthy control group 58 cases, 68 cases of Type II diabetes group were analyzed. Chromatographic conditions: DB-5MS column; the carrier gas He; flow rate of 1 mL·min-1, the injection volume 1 uL; split ratio is 100: 1. MS conditions: electron impact (EI) ion source, an auxiliary temperature of 280°C, the ion source 230°C, quadrupole 150°C; mass scan range 30~600 mAu. Results: Established analytical method based on urine metabolomics GC-MS of Type II diabetes, determine the urine succinic acid, L-leucine, L-isoleucine, tyrosine, slanine, acetoace acid, mannose, L-isoleucine, L-threonine, Phenylalanine, fructose, D-glucose, palmi acid, oleic acid and arachidonic acid were significantly were significantly changed. Conclusion: Based on metabolomics of GC-MS detection and analysis metabolites can be found differences between type 2 diabetes and healthy control group, PCA diagram can effectively distinguish Type II diabetes and healthy control group, with load diagrams and PLS-DA VIP value metabolite screening, the resulting differences in metabolic pathways involved metabolites, including amino acid metabolism, lipid metabolism, glucose metabolism and energy metabolism. PMID:27508010

  14. Development of an LC/MS/MS method in order to determine arctigenin in rat plasma: its application to a pharmacokinetic study.

    PubMed

    Zou, Quanfei; Gu, Yuan; Lu, Rong; Zhang, Tiejun; Zhao, Guang-Rong; Liu, Changxiao; Si, Duanyun

    2013-09-01

    In this study, a simple and sensitive LC/MS/MS method was developed and validated for the determination of arctigenin in rat plasma. The MS detection was performed using multiple reaction monitoring at the transitions of m/z 373.2 → 137.3 for arctigenin and m/z 187.1 → 131.0 for psoralen (internal standard) with a Turbo IonSpray electrospray in positive mode. The calibration curves fitted a good linear relationship over the concentration range of 0.2-500 ng/mL. It was found that arctigenin is not stable enough at both room temperature and -80 °C unless mixed with methanol before storage. The validated LC/MS/MS method was successfully applied for the pharmacokinetic study of arctigenin in rats. After intravenous injection of 0.3 mg/kg arctigenin injection to rats, the maximum concentration, half-life and area under the concentration-time curve were 323 ± 65.2 ng/mL, 0.830 ± 0.166 and 81.0 ± 22.1 h ng/mL, respectively.

  15. Study of flavour compounds from orange juices by HS-SPME and GC-MS

    NASA Astrophysics Data System (ADS)

    Schmutzer, G.; Avram, V.; Covaciu, F.; Feher, I.; Magdas, A.; David, L.; Moldovan, Z.

    2013-11-01

    The flavour of the orange juices, which gives the taste and odour of the product, is an important criterion about the products quality for consumers. A fresh single strength and two commercial orange juices (obtained from concentrate) flavour profile were studied using a selective and sensitive gas chromatography - mass spectrometry (GC-MS) analytical system, after a solvent free, single step preconcentration and extraction technique, the headspace solid phase microextraction (HP-SPME). In the studied orange juices 55 flavour compounds were detected and classified as belonging to the esters, alcohols, ketones, monoterpenes and sesquiterpenes chemical families. The fresh single strength orange juice was characterized by high amount of esters, monoterpenes and sesquiterpenes. Limonene and valencene were the most abundant flavours in this fresh natural orange juice. Alcohols and ketones were found in higher concentration in the commercial orange juices made from concentrate, than in the single strength products. Nevertheless, in commercial juices the most abundant flavour was limonene and α-terpineol. The results highlight clear differences between fresh singles strength orange juice and juice from concentrate. The orange juices reconstructed from concentrate, made in Romania, present low quantity of flavour compounds, suggesting the absence or a low rearomatization process, but extraneous components were not detected.

  16. Depth Profiling (ICP-MS) Study of Trace Metal `Grains' in Solid Asphaltenes

    NASA Astrophysics Data System (ADS)

    Pillay, Avin E.; Bassioni, Ghada; Stephen, Sasi; Kühn, Fritz E.

    2011-08-01

    Knowledge of trace metal `grains' in asphaltenes could play a significant role in enhancing refining and processing of crudes and also in providing useful information on mechanistic and migratory features linked to asphaltenes. These metals originate directly from interaction of oils with source-rock, mineral matter, and formation water and their accumulation in asphaltene matrices could vary from oil well to oil well. Suitable asphaltene samples were subjected to high-performance ICP-MS laser depth profiling (213 nm) to depths of 50 μm at 5 μm intervals. The study was conducted in the absence of standardization and characteristic intensities originating from the metals of interest were measured. Ten metal profiles were investigated (Na, Mg, Al, Mn, Fe, Zn, Sr, Pb, V, and Ni). The experimental results showed non-uniform distribution of trace metals and identified areas where such metals agglomerate. The data suggested that certain chemical and physical conditions within the structure of asphaltenes are favorable for metal `grain' formation at specific points. The exact mechanism for this behavior is not clear at this stage, and has considerable scope for future studies, including mathematical modeling simulations of asphaltenes. We also found that solid asphaltenes could be a useful forerunner of scale formation.

  17. Use of Simulation to Study Nurses' Acceptance and Nonacceptance of Clinical Decision Support Suggestions.

    PubMed

    Sousa, Vanessa E C; Lopez, Karen Dunn; Febretti, Alessandro; Stifter, Janet; Yao, Yingwei; Johnson, Andrew; Wilkie, Diana J; Keenan, Gail M

    2015-10-01

    Our long-term goal was to ensure nurse clinical decision support works as intended before full deployment in clinical practice. As part of a broader effort, this pilot project explored factors influencing acceptance/nonacceptance of eight clinical decision support suggestions displayed in an electronic health record-based nursing plan of care software prototype. A diverse sample of 21 nurses participated in this high-fidelity clinical simulation experience and completed a questionnaire to assess reasons for accepting/not accepting the clinical decision support suggestions. Of 168 total suggestions displayed during the experiment (eight for each of the 21 nurses), 123 (73.2%) were accepted, and 45 (26.8%) were not accepted. The mode number of acceptances by nurses was seven of eight, with only two of 21 nurses accepting all. The main reason for clinical decision support acceptance was the nurse's belief that the suggestions were good for the patient (100%), with other features providing secondary reinforcement. Reasons for nonacceptance were less clear, with fewer than half of the subjects indicating low confidence in the evidence. This study provides preliminary evidence that high-quality simulation and targeted questionnaires about specific clinical decision support selections offer a cost-effective means for testing before full deployment in clinical practice.

  18. The effect of women's suggestive clothing on men's behavior and judgment: a field study.

    PubMed

    Guéguen, Nicolas

    2011-10-01

    Numerous studies have shown that men overestimate the sexual intent of women based on their clothing style; however, this hypothesis has not been assessed empirically in a natural setting. This small field study measured the time it took for men to approach two female confederates sitting in a tavern, one wearing suggestive clothes and one wearing more conservative clothes. The behavior of 108 men was observed over 54 periods on 16 different nights in two different taverns. The time it took for the men to approach after initial eye contact was significantly shorter in the suggestive clothing condition. The men were also asked by male confederates to rate the likelihood of having a date with the women, and having sex on the first date. The men rated their chances to have a date and to have sex significantly higher in the suggestive clothing condition. Results are discussed with respect to men's possible misinterpretation that women's clothing indicates sexual interest, and the risks associated with the misinterpretation.

  19. Simultaneous determination of leucine, isoleucine and valine in Beagle dog plasma by HPLC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Wang, Ting; Xie, Huiru; Chen, Xu; Jiang, Xuehua; Wang, Ling

    2015-10-10

    Leucine (Leu), isoleucine (Ile) and valine (Val) are three branched-chain amino acids (BCAAs), which have been widely used as dietary supplements for professional athletes and patients with liver failure or catabolic diseases. To date, no pharmacokinetic studies of BCAAs in vivo useful for the assessment of clinical effect following daily intake has been reported. Thus in this study, an HPLC-MS/MS method for simultaneous determination of Leu, Ile and Val in Beagle dog plasma using homoarginine as the internal standard was developed and validated in terms of specificity, linearity, precision, accuracy, and stability. This assay method was then applied to a pharmacokinetic study of BCAAs in dogs following oral administration of 0.25 g/kg and 0.50 g/kg BCAAs. The HPLC-MS/MS method was found to be sensitive and reproducible for quantification of BCAAs in dog plasma and successfully applied to the pharmacokinetic study. All these BCAAs were well absorbed with a substantial increase in the plasma concentration after a baseline modification. No statistical significance was identified in different gender group and no drug accumulation was observed following multiple doses.

  20. Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) in toxicological analysis. Studies on the detection of clobenzorex and its metabolites within a systematic toxicological analysis procedure by GC-MS and by immunoassay and studies on the detection of alpha- and beta-amanitin in urine by atmospheric pressure ionization electrospray LC-MS.

    PubMed

    Maurer, H H; Kraemer, T; Ledvinka, O; Schmitt, C J; Weber, A A

    1997-02-07

    GC-MS is the method of choice for toxicological analysis of toxicants volatile in GC while non-volatile and/or thermally labile toxicants need LC-MS for their determination. Studies are presented on the toxicological detection of the amphetamine-like anorectic clobenzorex in urine by GC-MS after acid hydrolysis, extraction and acetylation and by fluorescence polarization immunoassay (FPIA, TDx (meth)amphetamine II). After ingestion of 60 mg of clobenzorex, the parent compound and/or its metabolites could be detected by GC-MS for up to 84 h or by FPIA for up to 60 h. Since clobenzorex shows no cross-reactivity with the used immunoassay, the N-dealkylated metabolite amphetamine is responsible for the positive TDx results. The intake of clobenzorex instead of amphetamine can be differentiated by GC-MS detection of hydroxyclobenzorex which is detectable for at least as long as amphetamine. In addition, the described GC-MS procedure allows the simultaneous detection of most of the toxicologically relevant drugs. Furthermore, studies are described on the atmospheric pressure ionization electrospray LC-MS detection of alpha- and beta-amanitin, toxic peptides of amanita mushrooms, in urine after solid-phase extraction on RP-18 columns. Using the single ion monitoring mode with the ions m/z 919 and 920 the amanitins could be detected down to 10 ng/ml of urine which allows us to diagnose intoxications with amanita mushrooms.

  1. Determination of Triphenylmethane Dyes and Their Metabolites in Salmon, Catfish, and Shrimp by LC-MS/MS Using AOAC First Action Method 2012.25: Collaborative Study.

    PubMed

    Schneider, Marilyn J; Andersen, Wendy C

    2015-01-01

    A collaborative study was conducted to evaluate the AOAC First Action 2012.25 LC-MS/MS analytical method for the determination of residues of three triphenylmethane dyes (malachite green, crystal violet, and brilliant green) and their metabolites (leucomalachite green and leucocrystal violet) in seafood. Fourteen laboratories from the United States, Canada, and the European Union member states participated in the study including national and state regulatory laboratories, university and national research laboratories, and private analytical testing laboratories. A variety of LC-MS/MS instruments were used for the analysis. Each participating laboratory received blinded test samples in duplicate of salmon, catfish, and shrimp consisting of negative control matrix; matrix fortified with residues at 0.42, 0.90, and 1.75 μg/kg; and samples of incurred matrix. The analytical results from each participating laboratory were evaluated for both quantitative residue determination and qualitative identification of targeted analytes. Results from statistical analysis showed that this method provided excellent trueness (generally ≥90% recovery) and precision (RSDr generally ≤10%, HorRat<1). The Study Directors recommend Method 2012.25 for Final Action status.

  2. Field study suggests that sex determination in sea lamprey is directly influenced by larval growth rate

    USGS Publications Warehouse

    Johnson, Nicholas; Swink, William D.; Brenden, Travis O.

    2017-01-01

    Sex determination mechanisms in fishes lie along a genetic-environmental continuum and thereby offer opportunities to understand how physiology and environment interact to determine sex. Mechanisms and ecological consequences of sex determination in fishes are primarily garnered from teleosts, with little investigation into basal fishes. We tagged and released larval sea lamprey (Petromyzon marinus) into unproductive lake and productive stream environments. Sex ratios produced from these environments were quantified by recapturing tagged individuals as adults. Sex ratios from unproductive and productive environments were initially similar. However, sex ratios soon diverged, with unproductive environments becoming increasingly male-skewed and productive environments becoming less male-skewed with time. We hypothesize that slower growth in unproductive environments contributed to the sex ratio differences by directly influencing sex determination. To the best of our knowledge, this is the first study suggesting that growth rate in a fish species directly influences sex determination; other studies have suggested that the environmental variables to which sex determination is sensitive (e.g. density, temperature) act as cues for favourable or unfavourable growth conditions. Understanding mechanisms of sex determination in lampreys may provide unique insight into the underlying principles of sex determination in other vertebrates and provide innovative approaches for their management where valued and invasive.

  3. Sphincter of Oddi dysfunction Type III: New studies suggest new approaches are needed.

    PubMed

    Wilcox, C Mel

    2015-05-21

    Sphincter of Oddi dysfunction (SOD) has been classified into three types based upon the presence or absence of objective findings including liver test abnormalities and bile duct dilatation. Type III is the most controversial and is classified as biliary type pain in the absence of any these objective findings. Many prior studies have shown that the clinical response to endoscopic therapy is higher based upon the presence of these objective criteria. However, there has been variable correlation of the manometry findings to outcome after endoscopic therapy. Nevertheless, manometry and sphincterotomy has been recommended for Type III patients given the overall response rate of 33%, although the reported response rates are highly variable. However, all of the prior data was non-blinded and non-randomized with variable follow-up. The evaluating predictors in SOD study - a prospective randomized blinded sham controlled one year outcome study showed no correlation between manometric findings and outcome after sphincterotomy. Furthermore, patients receiving sham therapy had a statistically significantly better outcome than those undergoing biliary or dual sphincterotomy. This study calls into question the whole concept of SOD Type III and, based upon prior physiologic studies, one can suggest that SOD Type III likely represents a right upper quadrant functional abdominal pain syndrome and should be treated as such.

  4. Sensitive LC-MS/MS-ESI method for simultaneous determination of montelukast and fexofenadine in human plasma: application to a bioequivalence study.

    PubMed

    Muppavarapu, Rajendraprasad; Guttikar, Swati; Rajappan, Manavalan; Kamarajan, Kannan; Mullangi, Ramesh

    2014-08-01

    A rapid, simple, sensitive and selective LC-MS/MS method was developed and validated for simultaneous quantification of montelukast (MT) and fexofenadine (FF) in human plasma (200 μL) using montelukast-d6 (MT-d6 ) and fexofenadine-d10 (FF-d10 ), respectively as an internal standard (IS) as per the US Food and Drug Administration guidelines. The chromatographic resolution was achieved on a Chromolith RP18e column using an isocratic mobile phase consisting of 20 mm ammonium formate-acetonitrile (20:80, v/v) at flow rate of 1.2 mL/min. The LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. The total run time of analysis was 4 min and elution of MT, FF, MT-d6 and FF-d10 occurred at 2.5, 1.2, 2.4 and 1.2 min, respectively. The standard curve found to be linear in the range 2.00-1000 ng/mL with a coefficient of correlation of ≥0.99 for both the drugs. The intra- and inter-day accuracy and precision values for MT and FF met the acceptance as per FDA guidelines. MT and FF were found to be stable in a battery of stability studies viz., bench-top, auto-sampler and repeated freeze-thaw cycles. The validated assay was applied to an oral bioequivalence study in humans.

  5. Development and validation of sensitive LC/MS/MS method for quantitative bioanalysis of levonorgestrel in rat plasma and application to pharmacokinetics study.

    PubMed

    Ananthula, Suryatheja; Janagam, Dileep R; Jamalapuram, Seshulatha; Johnson, James R; Mandrell, Timothy D; Lowe, Tao L

    2015-10-15

    Rapid, sensitive, selective and accurate LC/MS/MS method was developed for quantitative determination of levonorgestrel (LNG) in rat plasma and further validated for specificity, linearity, accuracy, precision, sensitivity, matrix effect, recovery efficiency and stability. Liquid-liquid extraction procedure using hexane:ethyl acetate mixture at 80:20 v:v ratio was employed to efficiently extract LNG from rat plasma. Reversed phase Luna column C18(2) (50×2.0mm i.d., 3μM) installed on a AB SCIEX Triple Quad™ 4500 LC/MS/MS system was used to perform chromatographic separation. LNG was identified within 2min with high specificity. Linear calibration curve was drawn within 0.5-50ng·mL(-1) concentration range. The developed method was validated for intra-day and inter-day accuracy and precision whose values fell in the acceptable limits. Matrix effect was found to be minimal. Recovery efficiency at three quality control (QC) concentrations 0.5 (low), 5 (medium) and 50 (high) ng·mL(-1) was found to be >90%. Stability of LNG at various stages of experiment including storage, extraction and analysis was evaluated using QC samples, and the results showed that LNG was stable at all the conditions. This validated method was successfully used to study the pharmacokinetics of LNG in rats after SubQ injection, providing its applicability in relevant preclinical studies.

  6. A Multidisciplinary Approach to Study the Role of the Gut Microbiome in Relapsing and Progressive MS

    DTIC Science & Technology

    2016-10-01

    for this study at UCSF and Mt Sinai, Clinical evaluation and invitations to participate, mailing kits have been designed, prepared and started to...eligible patients from MS clinic at UCSF and Mt Sinai. Subtask 2: Clinical evaluation and invitation to participate in the study Major Task 3: Sample...unaffected controls. Blood samples were collected for all 17 subjects and these subjects completed their clinical visits and questionnaires. Stool

  7. The future of liquid chromatography-mass spectrometry (LC-MS) in metabolic profiling and metabolomic studies for biomarker discovery

    PubMed Central

    Metz, Thomas O.; Zhang, Qibin; Page, Jason S.; Shen, Yufeng; Callister, Stephen J.; Jacobs, Jon M.; Smith, Richard D.

    2008-01-01

    SUMMARY The future utility of liquid chromatography-mass spectrometry (LC-MS) in metabolic profiling and metabolomic studies for biomarker discover will be discussed, beginning with a brief description of the evolution of metabolomics and the utilization of the three most popular analytical platforms in such studies: NMR, GC-MS, and LC-MS. Emphasis is placed on recent developments in high-efficiency LC separations, sensitive electrospray ionization approaches, and the benefits to incorporating both in LC-MS-based approaches. The advantages and disadvantages of various quantitative approaches are reviewed, followed by the current LC-MS-based tools available for candidate biomarker characterization and identification. Finally, a brief prediction on the future path of LC-MS-based methods in metabolic profiling and metabolomic studies is given. PMID:19177179

  8. Limitations on Recently Suggested Atom Interferometry Mission Concepts for Gravitational Wave Studies

    NASA Astrophysics Data System (ADS)

    Bender, Peter L.

    2012-03-01

    In late 2011, suggestions were made of two new atom interferometry mission concepts for gravitational wave studies. [A presentation by B. N. Saif on these concepts is available on the NASA Physics of the Cosmos website under ``Workshop on Gravitational Wave Mission Architectural Concepts'' (Dec. 20-21, 2011)]. The concepts were for measurements between atom clouds separated by distances of L=500 m or L=500 km. At GW frequencies of 0.1 to 10 Hz, sinusoidal variations in the separations dX between two parts of the atom wavefunctions would be induced by motion of the nulls in the optical potential, using the Bloch oscillation approach. But some apparent limitations of this approach are as follows: the S/N required for achieving the strain sensitivities shown appears to be much higher than the value given in the example in the presentation; the large sinusoidal variations required in the control laser frequency make it difficult to use high finesse cavity mode-cleaners to reduce the effects of laser wavefront aberration fluctuations; very small fluctuations in the temperature or size of the atom clouds would cause serious additional noise, particularly for the L=500 m case; and for the L=500 mission concept, the 10-20 W suggested laser power does not seem to permit keeping the spontaneous emission rate low. However, the main issue is that the required atom interferometry systems appear to be far more complex than the gravitational reference sensors that they would replace.

  9. An Efficient Approach to Evaluate Reporter Ion Behavior from MALDI-MS/MS Data for Quantification Studies Using Isobaric Tags.

    PubMed

    Cologna, Stephanie M; Crutchfield, Christopher A; Searle, Brian C; Blank, Paul S; Toth, Cynthia L; Ely, Alexa M; Picache, Jaqueline A; Backlund, Peter S; Wassif, Christopher A; Porter, Forbes D; Yergey, Alfred L

    2015-10-02

    Protein quantification, identification, and abundance determination are important aspects of proteome characterization and are crucial in understanding biological mechanisms and human diseases. Different strategies are available to quantify proteins using mass spectrometric detection, and most are performed at the peptide level and include both targeted and untargeted methodologies. Discovery-based or untargeted approaches oftentimes use covalent tagging strategies (i.e., iTRAQ, TMT), where reporter ion signals collected in the tandem MS experiment are used for quantification. Herein we investigate the behavior of the iTRAQ 8-plex chemistry using MALDI-TOF/TOF instrumentation. The experimental design and data analysis approach described is simple and straightforward, which allows researchers to optimize data collection and proper analysis within a laboratory. iTRAQ reporter ion signals were normalized within each spectrum to remove peptide biases. An advantage of this approach is that missing reporter ion values can be accepted for purposes of protein identification and quantification without the need for ANOVA analysis. We investigate the distribution of reporter ion peak areas in an equimolar system and a mock biological system and provide recommendations for establishing fold-change cutoff values at the peptide level for iTRAQ data sets. These data provide a unique data set available to the community for informatics training and analysis.

  10. Assessment of CE-ICP/MS hyphenation for the study of uranyl/protein interactions.

    PubMed

    Huynh, Thi-Ngoc Suong; Bourgeois, Damien; Basset, Christian; Vidaud, Claude; Hagège, Agnès

    2015-06-01

    Identification of uranyl transport proteins is key to develop efficient detoxification approaches. Therefore, analytical approaches have to be developed to cope with the complexity of biological media and allow the analysis of metal speciation. CE-ICP/MS was used to combine the less-intrusive character and high separation efficiency of CE with the sensitive detection of ICP/MS. The method was based on the incubation of samples with uranyl prior to the separation. Electrophoretic buffers were compared to select a 10 mM Tris to 15 mM NaCl buffer, which enabled analyses at pH 7.4 and limited dissociation. This method was applied to the analysis of a serum. Two main fractions were observed. By comparison with synthetic mixtures of proteins, the first one was attributed to fetuin and in a lesser extent to HSA, and the second one to uranyl unbound to proteins. The analysis showed that fetuin was likely to be the main target of uranyl. CE-ICP/MS was also used to investigate the behavior of the fetuin-uranyl complex, in the presence of carbonate, an abundant complexing agent of uranyl in blood. This method enabled association constants determination, suggesting the occurrence of both FETUA(UO2(2+)) and FETUA(UO2(2+))(CO3(2-)) complexes, depending on the carbonate concentration.

  11. In vitro studies of plasmid-mediated penicillinase from Streptococcus faecalis suggest a staphylococcal origin.

    PubMed Central

    Murray, B E; Mederski-Samoraj, B; Foster, S K; Brunton, J L; Harford, P

    1986-01-01

    A strain of Streptococcus faecalis with plasmid-mediated penicillinase production was studied further. Partially purified penicillinase from the S. faecalis strain hydrolyzed penicillin, ampicillin, and ureido-penicillins but not penicillinase-resistant semisynthetic penicillins, cephalosporins, or imipenem; hydrolysis was inhibited by clavulanic acid. Hydrolysis of a given antibiotic correlated with a marked increase in the minimal inhibitory concentration (MIC) of that drug when a high inoculum was used. As with most enterococci, the MICs of cephalosporins and penicillinase-resistant semisynthetic penicillins were too high for clinical usefulness, although these agents did not show an inoculum effect. Based upon hybridization under stringent conditions of plasmid DNA from the S. faecalis strain to cloned penicillinase genes from Staphylococcus aureus, it appears that these resistance determinants are highly homologous and suggests that this enzyme was introduced into streptococci from staphylococci. Images PMID:3080475

  12. Development and validation of sensitive and rapid UPLC-MS/MS method for quantitative determination of daclatasvir in human plasma: Application to a bioequivalence study.

    PubMed

    Rezk, Mamdouh R; Bendas, Ehab R; Basalious, Emad B; Karim, Iman A

    2016-09-05

    A rapid and sensitive UPLC-MS/MS method was developed and validated for determination of daclatasvir (DAC) in human plasma using sofosbuvir (SOF) as an internal standard (IS). The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Precipitation with acetonitrile was used in sample preparation. The prepared samples were chromatographed on Acquity UPLC HSS C18 (50×2.1mm, 1.8μm) column by pumping 10mM ammonium formate (pH 3.5) and acetonitrile in an isocratic mode at a flow rate of 0.30ml/min. Method validation was performed as per the FDA guidelines and the standard curves were found to be linear in the range of 5-4000ng/ml for DAC. The intra-day and inter-day precision and accuracy results were within the acceptable limits. A very short run time of 1.2min made it possible to analyze more than 500 human plasma samples per day. The wider range of quantification of DAC allowed the applicability of the developed method for its determination in a bioequivalence study in human volunteers.

  13. Development of a sensitive UPLC-ESI-MS/MS method for quantification of sofosbuvir and its metabolite, GS-331007, in human plasma: Application to a bioequivalence study.

    PubMed

    Rezk, Mamdouh R; Basalious, Emad B; Karim, Iman A

    2015-10-10

    A rapid and simple LC-MS/MS method was developed and validated for the simultaneous estimation of sofosbuvir (SF) and its metabolite GS-331007 (GS) using famotidine as an internal standard (IS). The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Extraction with ethyl acetate was used in sample preparation. The prepared samples were chromatographed on Acquity UPLC HSS C₁₈ (50 mm × 2.1 mm, 1.8 μm) column by pumping 0.1% formic acid and acetonitrile (50:50, v/v) in an isocratic mode at a flow rate of 0.3 ml/min. Method validation was performed as per the FDA guidelines and the standard curves were found to be linear in the range of 10-2500 ng/ml for both SF and its metabolite. The intra-day and inter-day precision and accuracy results were within the acceptable limits. A very short run time of 1.2 min made it possible to analyze more than 300 human plasma samples per day. The developed assay method was successfully applied to a bioequivalence study in human volunteers.

  14. LC-DAD/ESI-MS/MS study of phenolic compounds in ash (Fraxinus excelsior L. and F. americana L.) heartwood. Effect of toasting intensity at cooperage.

    PubMed

    Sanz, Miriam; de Simón, Brígida Fernández; Cadahía, Estrella; Esteruelas, Enrique; Muñoz, Angel M; Hernández, Teresa; Estrella, Isabel; Pinto, Ernani

    2012-07-01

    The phenolic composition of heartwood extracts from Fraxinus excelsior L. and F. americana L., both before and after toasting in cooperage, was studied using LC-DAD/ESI-MS/MS. Low-molecular weight (LMW) phenolic compounds, secoiridoids, phenylethanoid glycosides, dilignols and oligolignols compounds were detected, and 48 were identified, or tentatively characterized, on the basis of their retention time, UV/Vis and MS spectra, and MS fragmentation patterns. Some LMW phenolic compounds like protocatechuic acid and aldehyde, hydroxytyrosol and tyrosol, were unlike to those for oak wood, while ellagic and gallic acid were not found. The toasting of wood resulted in a progressive increase in lignin degradation products with regard to toasting intensity. The levels of some of these compounds in medium-toasted ash woods were much higher than those normally detected in toasted oak, highlighting vanillin levels, thus a more pronounced vanilla character can be expected when using toasted ash wood in the aging wines. Moreover, in seasoned wood, we found a great variety of phenolic compounds which had not been found in oak wood, especially oleuropein, ligstroside and olivil, along with verbascoside and isoverbascoside in F. excelsior, and oleoside in F. americana. Toasting mainly provoked their degradation, thus in medium-toasted wood, only four of them were detected. This resulted in a minor differentiation between toasted ash and oak woods. The absence of tannins in ash wood, which are very important in oak wood, is another peculiar characteristic that should be taken into account when considering its use in cooperage.

  15. Validation of a confirmatory method of salbutamol in sheep hair by UPLC-MS/MS and its application to pharmacokinetic study.

    PubMed

    Decheng, Suo; Wei, Zhang; Yu, Zhang; Genlong, Zhao; Ruigou, Wang; PeiLong, Wang; Xiaoou, Su

    2015-10-10

    A new method for determining salbutamol in hair of sheep by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was established. Samples were extracted with 0.1M of HCl solution. The mixture was heated to 60 °C in a water bath and kept at this temperature for 4h. The extracts were purified through SPE method and then dried with nitrogen. Residues were redissolved in mobile phase. The target compound was determined by UPLC-MS/MS with BEH-C18 column. The usefulness and feasibility of different treatment procedures of hair containing salbutamol were evaluated. The range of linearity was 1-100 ng/g. The LOD was 0.3 ng/g, and the LOQ was 1 ng/g. Recoveries were 89-106%, and coefficients of variation were 3.2-13.9%. Pharmacokinetics of salbutamol was studied in healthy sheep after oral administration of 150 μg/kg body weight salbutamol for 21 consecutive days. Salbutamol residues in hair were still detected after 21 days of administration.

  16. Measurement of fexofenadine concentration in micro-sample human plasma by a rapid and sensitive LC-MS/MS employing protein precipitation: application to a clinical pharmacokinetic study.

    PubMed

    Guo, Daqing; Zou, Jianjun; Zhu, Yubing; Lou, Sheng; Fan, Hongwei; Qin, Qun

    2010-03-01

    A simple, rapid and sensitive liquid chromatography/positive ion electro-spray tandem mass spectrometry method (LC-MS/MS) was developed and validated for the quantification of fexofenadine with 100 microL human plasma employing glipizide as internal standard (IS). Protein precipitation was used in the sample preparation procedure. Chromatographic separation was achieved on a reversed-phase C(18 )column (5 microm, 100 x 2.1 mm) with methanol : buffer (containing 10 mmol/L ammonium acetate and 0.1% formic acid; 70 : 30, v/v) as mobile phase. The total chromatographic runtime was approximately 3.0 min with retention time for fexofenadine and IS at approximately 1.9 and 2.1 min, respectively. Detection of fexofenadine and IS was achieved by LC-MS/MS in positive ion mode using 502.1 --> 466.2 and 446.0 --> 321.1 transitions, respectively. The method was proved to be accurate and precise at linearity range of 1-600 ng/mL with a correlation coefficient (r) of > or =0.9976. The validated method was applied to a pharmacokinetic study in human volunteers following oral administration of 60 or 120 mg fexofenadine formulations, successfully.

  17. HPLC and HPLC/MS/MS Studies on Stress, Accelerated and Intermediate Degradation Tests of Antivirally Active Tricyclic Analog of Acyclovir.

    PubMed

    Lesniewska, Monika A; Dereziński, Paweł; Klupczyńska, Agnieszka; Kokot, Zenon J; Ostrowski, Tomasz; Zeidler, Joanna; Muszalska, Izabela

    2015-01-01

    The degradation behavior of a tricyclic analog of acyclovir [6-(4-MeOPh)-TACV] was determined in accordance with International Conference on Harmonization guidelines for good clinical practice under different stress conditions (neutral hydrolysis, strong acid/base degradation, oxidative decomposition, photodegradation, and thermal degradation). Accelerated [40±2°C/75%±5% relative humidity (RH)] and intermediate (30±2°C/65%±5% RH) stability tests were also performed. For observation of the degradation of the tested compound the RP-HPLC was used, whereas for the analysis of its degradation products HPLC/MS/MS was used. Degradation of the tested substance allowed its classification as unstable in neutral environment, acidic/alkaline medium, and in the presence of oxidizing agent. The tested compound was also light sensitive and was classified as photolabile both in solution and in the solid phase. However, the observed photodegradation in the solid phase was at a much lower level than in the case of photodegradation in solution. The study showed that both air temperature and RH had no significant effect on the stability of the tested substance during storage for 1 month at 100°C (dry heat) as well as during accelerated and intermediate tests. Based on the HPLC/MS/MS analysis, it can be concluded that acyclovir was formed as a degradation product of 6-(4-MeOPh)-TACV.

  18. Determination of Sodium Tanshinone IIA Sulfonate in human plasma by LC-MS/MS and its application to a clinical pharmacokinetic study.

    PubMed

    Qin, WeiWei; Wang, Bin; Lu, XiaoPei; Liu, HaiMing; Wang, Li; Qi, WeiLin

    2016-03-20

    An assay based on protein precipitation and liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated for the quantitative analysis of Sodium Tanshinone IIA Sulfonate (STS) in human plasma. After the addition of dehydroepiandrosterone-D5-3-sulfate sodium salt (DHEAS-D5) as internal standard (IS) and formic acid, plasma samples were prepared by one-step protein precipitation with a mixture of acetonitrile and methanol. Isocratic mobile phase consisted of 0.4 mmol/L ammonium formate buffer (16 ppm formic acid)/acetonitrile (40/60, v/v) on a XSELECT™ HSS T3 column. Detection was performed on a triple-quadrupole mass spectrometer utilizing an electrospray ionization (ESI) interface operating in positive ion and selected reaction monitoring (SRM) mode with the precursor to product ion transitions m/z 373.3→357.1 for STS and m/z 373.0→97.8 for the IS. Calibration curves of STS in human plasma were linear (r=0.9957-0.9998) over the concentration range of 2-1000 ng/mL with acceptable accuracy and precision. The lower limit of quantification in human plasma was 2 ng/mL. The validated LC-MS/MS method has been successfully applied to a pharmacokinetic study of STS in Chinese healthy male volunteers.

  19. Quantification of sofosbuvir and ledipasvir in human plasma by UPLC-MS/MS method: Application to fasting and fed bioequivalence studies.

    PubMed

    Rezk, Mamdouh R; Bendas, Ehab R; Basalious, Emad B; Karim, Iman A

    2016-08-15

    A rapid and sensitive LC-MS/MS method was developed, optimized and validated for quantification of sofosbuvir (SF) and ledipasvir (LD) in human plasma using eplerenone as an internal standard (IS). Analytes and IS were extracted from plasma by simple liquid-liquid extraction technique using methyl tertiary butyl ether. The prepared samples were chromatographed on Acquity UPLC BEH C18 column. Separation was done using a mobile phase formed of 0.1% formic acid and acetonitrile (50:50, v/v) in an isocratic mode at a flow rate of 0.4ml/min. The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. A full validation of the method was performed according to the FDA guidelines. Linearity was found to be in the range of 0.25-3500ng/ml for SF and 5-2000ng/ml for LD. The intra-day and inter-day precision and accuracy results were within the acceptable limits. A short run time of 2min allows analysis of more than 400 plasma samples per day. The developed method was successfully applied to both fasting and fed bioequivalence studies in healthy human volunteers.

  20. GC-MS and LC-(high-resolution)-MS(n) studies on the metabolic fate and detectability of camfetamine in rat urine.

    PubMed

    Welter, Jessica; Kavanagh, Pierce; Maurer, Hans H

    2014-06-01

    Camfetamine (N-methyl-3-phenyl-norbornan-2-amine; CFA) belongs as amphetamine-type stimulant to the so-called new psychoactive substances. CFA is an analogue of fencamfamine, an appetite suppressant developed in the 1960s. The described effects of CFA are slight stimulation and increased vigilance and the side effects are tachycardia, paranoia, and sleeplessness. The aims of the presented work were to study the metabolic fate and the detectability of CFA in urine and to elucidate which cytochrome-P450 (CYP) isoenzymes are involved in the main metabolic steps. For metabolism studies, rat urine samples were isolated by solid-phase extraction without and after enzymatic cleavage of conjugates. The phase I metabolites were separated and identified after/without acetylation by gas chromatography-mass spectrometry (GC-MS) and/or liquid chromatography-high resolution-linear ion trap mass spectrometry (LC-HR-MS(n)), respectively, and the phase II metabolites by LC-HR-MS(n). From the identified metabolites, the following main metabolic pathways were deduced: N-demethylation, aromatic mono or bis-hydroxylation followed by methylation of one hydroxy group, hydroxylation of the norbornane ring, combination of these steps, and glucuronidation and/or sulfation of the hydroxy metabolites. The N-demethylation was catalyzed by CYP2B6, CYP2C19, CYP2D6, and CYP3A4, the aromatic hydroxylation by CYP2C19 and CYP2D6, and the aliphatic hydroxylation was catalyzed by CYP1A2, CYP2B6, CYP2C19, and CYP3A4. Finally, the intake of a common user's dose of CFA could be confirmed in rat urine using the authors' GC-MS and the LC-MS(n) standard urine screening approaches via CFA and several metabolites, with the hydroxy-aryl CFA and the corresponding glucuronide being the most abundant.

  1. 2-methiopropamine, a thiophene analogue of methamphetamine: studies on its metabolism and detectability in the rat and human using GC-MS and LC-(HR)-MS techniques.

    PubMed

    Welter, Jessica; Meyer, Markus R; Wolf, Ehud Udi; Weinmann, Wolfgang; Kavanagh, Pierce; Maurer, Hans H

    2013-04-01

    2-Methiopropamine [1-(thiophen-2-yl)-2-methylaminopropane, 2-MPA], a thiophene analogue of methamphetamine, is available from online vendors selling "research chemicals." The first samples were seized by the German police in 2011. As it is a recreational stimulant, its inclusion in routine drug screening protocols should be required. The aims of this study were to identify the phase I and II metabolites of 2-MPA in rat and human urine and to identify the human cytochrome-P450 (CYP) isoenzymes involved in its phase I metabolism. In addition, the detectability of 2-MPA in urine samples using the authors' well-established gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-linear ion trap-mass spectrometry (LC-MS(n)) screening protocols was also evaluated. The metabolites were isolated from rat and human urine samples by solid-phase extraction without or following enzymatic cleavage of conjugates. The phase I metabolites, following acetylation, were separated and identified by GC-MS and/or liquid chromatography-high-resolution linear ion trap mass spectrometry (LC-HR-MS(n)) and the phase II metabolites by LC-HR-MS(n). The following major metabolic pathways were proposed: N-demethylation, hydroxylation at the side chain and at the thiophene ring, and combination of these transformations followed by glucuronidation and/or sulfation. CYP1A2, CYP2C19, CYP2D6, and CYP3A4 were identified as the major phase I metabolizing enzymes. They were also involved in the N-demethylation of the analogue methamphetamine and CYP2C19, CYP2D6, and CYP3A4 in its ring hydroxylation. Following the administration of a typical user's dose, 2-MPA and its metabolites were identified in rat urine using the authors' GC-MS and the LC-MS(n) screening approaches. Ingestion of 2-MPA could also be detected by both protocols in an authentic human urine sample.

  2. A Multidisciplinary Approach to Study the Role of the Gut Microbiome in Relapsing and Progressive MS

    DTIC Science & Technology

    2016-10-01

    subjects and all subjects completed their clinic visits. Case report questionnaires are either completed or in progress for all subjects. Some reasons ...accomplishments to date include: HRPO approval, Chart reviews to identify eligible subjects for this study at UCSF and Mt Sinai, Clinical evaluation and...recruitment of research subjects Subtask 1: Perform Chart reviews to identify eligible patients from MS clinic at UCSF and Mt Sinai. Subtask 2: Clinical

  3. ABRF Proteome Informatics Research Group (iPRG) 2015 Study: Detection of Differentially Abundant Proteins in Label-Free Quantitative LC-MS/MS Experiments.

    PubMed

    Choi, Meena; Eren-Dogu, Zeynep F; Colangelo, Christopher; Cottrell, John; Hoopmann, Michael R; Kapp, Eugene A; Kim, Sangtae; Lam, Henry; Neubert, Thomas A; Palmblad, Magnus; Phinney, Brett S; Weintraub, Susan T; MacLean, Brendan; Vitek, Olga

    2017-02-03

    Detection of differentially abundant proteins in label-free quantitative shotgun liquid chromatography-tandem mass spectrometry (LC-MS/MS) experiments requires a series of computational steps that identify and quantify LC-MS features. It also requires statistical analyses that distinguish systematic changes in abundance between conditions from artifacts of biological and technical variation. The 2015 study of the Proteome Informatics Research Group (iPRG) of the Association of Biomolecular Resource Facilities (ABRF) aimed to evaluate the effects of the statistical analysis on the accuracy of the results. The study used LC-tandem mass spectra acquired from a controlled mixture, and made the data available to anonymous volunteer participants. The participants used methods of their choice to detect differentially abundant proteins, estimate the associated fold changes, and characterize the uncertainty of the results. The study found that multiple strategies (including the use of spectral counts versus peak intensities, and various software tools) could lead to accurate results, and that the performance was primarily determined by the analysts' expertise. This manuscript summarizes the outcome of the study, and provides representative examples of good computational and statistical practice. The data set generated as part of this study is publicly available.

  4. Characterization of a new rat urinary metabolite of piperine by LC/NMR/MS studies.

    PubMed

    Bajad, Sunil; Coumar, Mohane; Khajuria, Ravi; Suri, Om P; Bedi, Kasturi L

    2003-08-01

    Potential of piperine, an active alkaloid of black and long peppers, to increase the bioavailability of drugs in humans is of great clinical significance owing to its omnipresence in food. In an attempt to further study the reported differences in its metabolism in rats and humans, a new major urinary metabolite was detected in rat urine and plasma using HPLC. The metabolite was partially purified using reverse phase column chromatography on Sephadex((R))-LH 20 and characterized as 5-(3, 4-methylenedioxy phenyl)-2E,4E-pentadienoic acid-N-(3-yl propionic acid)-amide with the help of LC/NMR/positive ESI-MS studies. Complete mass fragmentation pattern could be assigned with MS/MS studies. The metabolite has a unique structure compared to the previously reported metabolites in that it retains methylenedioxy ring and conjugated double bonds while the piperidine ring is modified to form propionic acid group. Mechanism of formation of the metabolite by oxidation and cleavage of piperidine ring is proposed. Kidney appears to be the major excretion route for piperine metabolites in rats as no metabolite could be detected in feces.

  5. Metabolomic study of two rice lines infected by Rhizoctonia solani in negative ion mode by CE/TOF-MS.

    PubMed

    Suharti, Woro Sri; Nose, Akihiro; Zheng, Shao-Hui

    2016-11-01

    Rhizoctonia solani is a fungal pathogen that causes sheath blight disease in rice plants. In this study, metabolomic analysis using CE/TOF-MS in negative ion mode was used to investigate the resistance response of resistant and susceptible rice lines (32R and 29S, respectively) due to R. solani infection. Two rice lines showed different responses to the infection of R. solani. In 32R, R. solani infection induced significant increases in adenosine diphosphate (ADP), glyceric acid, mucic acid and jasmonic acid. In 29S, inosine monophosphate (IMP) was involved in the plant response to R. solani infection. Phenol compounds showed an increase as a response of the rice lines to R. solani infection. The study suggests that R. solani infection effects in 32R are associated with the induction of plant metabolic processes such as respiration, photorespiration, pectin synthesis, and lignin accumulation. In 29S, the R. solani infection is suggested to correlate with nitrogen metabolism.

  6. Genome-wide association studies of adolescent idiopathic scoliosis suggest candidate susceptibility genes.

    PubMed

    Sharma, Swarkar; Gao, Xiaochong; Londono, Douglas; Devroy, Shonn E; Mauldin, Kristen N; Frankel, Jessica T; Brandon, January M; Zhang, Dongping; Li, Quan-Zhen; Dobbs, Matthew B; Gurnett, Christina A; Grant, Struan F A; Hakonarson, Hakon; Dormans, John P; Herring, John A; Gordon, Derek; Wise, Carol A

    2011-04-01

    Adolescent idiopathic scoliosis (AIS) is an unexplained and common spinal deformity seen in otherwise healthy children. Its pathophysiology is poorly understood despite intensive investigation. Although genetic underpinnings are clear, replicated susceptibility loci that could provide insight into etiology have not been forthcoming. To address these issues, we performed genome-wide association studies (GWAS) of ∼327 000 single nucleotide polymorphisms (SNPs) in 419 AIS families. We found strongest evidence of association with chromosome 3p26.3 SNPs in the proximity of the CHL1 gene (P < 8 × 10(-8) for rs1400180). We genotyped additional chromosome 3p26.3 SNPs and tested replication in two follow-up case-control cohorts, obtaining strongest results when all three cohorts were combined (rs10510181 odds ratio = 1.49, 95% confidence interval = 1.29-1.73, P = 2.58 × 10(-8)), but these were not confirmed in a separate GWAS. CHL1 is of interest, as it encodes an axon guidance protein related to Robo3. Mutations in the Robo3 protein cause horizontal gaze palsy with progressive scoliosis (HGPPS), a rare disease marked by severe scoliosis. Other top associations in our GWAS were with SNPs in the DSCAM gene encoding an axon guidance protein in the same structural class with Chl1 and Robo3. We additionally found AIS associations with loci in CNTNAP2, supporting a previous study linking this gene with AIS. Cntnap2 is also of functional interest, as it interacts directly with L1 and Robo class proteins and participates in axon pathfinding. Our results suggest the relevance of axon guidance pathways in AIS susceptibility, although these findings require further study, particularly given the apparent genetic heterogeneity in this disease.

  7. Efficient approach for the detection and identification of new androgenic metabolites by applying SRM GC-CI-MS/MS: a methandienone case study.

    PubMed

    Polet, Michael; Van Gansbeke, Wim; Van Eenoo, Peter; Deventer, Koen

    2016-07-01

    Identification of anabolic androgenic steroids (AAS) is a vital issue in doping control and toxicology, and searching for metabolites with longer detection times remains an important task. Recently, a gas chromatography chemical ionization triple quadrupole mass spectrometry (GC-CI-MS/MS) method was introduced, and CI, in comparison with electron ionization (EI), proved to be capable of increasing the sensitivity significantly. In addition, correlations between AAS structure and fragmentation behavior could be revealed. This enables the search for previously unknown but expected metabolites by selection of their predicted transitions. The combination of both factors allows the setup of an efficient approach to search for new metabolites. The approach uses selected reaction monitoring which is inherently more sensitive than full scan or precursor ion scan. Additionally, structural information obtained from the structure specific CI fragmentation pattern facilitates metabolite identification. The procedure was demonstrated by a methandienone case study. Its metabolites have been studied extensively in the past, and this allowed an adequate evaluation of the efficiency of the approach. Thirty three metabolites were detected, including all relevant previously discovered metabolites. In our study, the previously reported long-term metabolite (18-nor-17β-hydroxymethyl,17α-methyl-androst-1,4,13-trien-3-one) could be detected up to 26 days by using GC-CI-MS/MS. The study proves the validity of the approach to search for metabolites of new synthetic AAS and new long-term metabolites of less studied AAS and illustrates the increase in sensitivity by using CI. Copyright © 2016 John Wiley & Sons, Ltd.

  8. LC/MS/MS determination and pharmacokinetic study of iridoid glycosides monotropein and deacetylasperulosidic acid isomers in rat plasma after oral administration of Morinda officinalis extract.

    PubMed

    Li, Chunmin; Dong, Jian; Tian, Jingchang; Deng, Zhipeng; Song, Xiujing

    2016-02-01

    Morinda officinalis is a famous traditional Chinese medicine containing iridoid glycoside compounds, such as monotropein and deacetylasperulosidic acid. The aim of the study was to develop a novel and sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) method for the simultaneous determination of the two isomeric iridoid glycosides and then evaluate their pharmacokinetic properties in rats. Selected-reaction monitoring mode was employed for quantification of two analytes in rat plasma. The calibration curves were linear over their respective concentration range with correlation coefficient >0.995 for both analytes. Precision for monotropein and deacetylasperulosidic acid ranged from 2.5 to 11.9% relative standard deviation, and the accuracy of two analytes was -2.0-3.7 and -6.4-10.7% relative error, respectively. This method was successfully applied in pharmacokinetic study after oral administration of M. officinalis extract in rats. The results provided a basis for further research on the bioactivity of M. officinalis.

  9. Determination and pharmacokinetic study of two triterpenoid saponins in rat plasma after oral administration of the extract of Aralia elata leaves by UHPLC-ESI-MS/MS.

    PubMed

    Wang, Zhibin; Wu, Qiong; Meng, Yonghai; Sun, Yichun; Wang, Qi; Yang, Chunjuan; Wang, Qiuhong; Yang, Bingyou; Kuang, Haixue

    2015-03-15

    Aralia elata (Miq.) Seems (A. elata) grow in Northeast China and the total saponins of A. elata is used to auxiliary treatment for the acute hepatitis, chronic hepatitis and the transaminase on the high side. Aralia-saponinV and Aralia-saponinVI are the major bioactive saponins in A. elata leaves. A selective and sensitive UHPLC-MS/MS method was developed and validated for the determination and pharmacokinetic study of Aralia-saponinV and Aralia-saponinVI indwelling the extract in rat plasma in this article. The sample pretreatment involved a one-step extraction of 0.2mL plasma with methanol. Shengmaxinside C was used as internal standard (I.S.). The separation was carried out on an Agilent SB-C18 column (1.8μm, 50mm×2.1mm) at 30°C with a mobile phase of acetonitrile-5mM ammonium acetate (90:10, v/v) at a flow rate of 0.2mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source operating in the negative ionization mode. The optimized mass transition ion-pairs (m/z) monitored for Aralia-saponinV, Aralia-saponinVI and I.S. were 1103.2/941.2, 1119.2/957.0 and 707.0/647.1, respectively. The current UHPLC-MS/MS assay method was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability, and it was suitable for the pharmacokinetic studies of the two saponins after oral administration of extract of A. elata leaves. The lower limits of quantification were 5.70ng/mL for Aralia-saponinV and 6.15ng/mL for Aralia-saponinVI. Intra-day and inter-day precisions were less than 7.4% and the accuracy range was from 1.19% to 8.60%. The mean extraction recoveries of analytes and I.S. from rat plasma were all more than 89.5%. This paper described a simple, sensitive and validated UHPLC-MS/MS method for simultaneous determination of Aralia-saponinV and Aralia-saponinVI in rat plasma after oral administration of the extract of A

  10. Biophysical studies suggest a new structural arrangement of crotoxin and provide insights into its toxic mechanism.

    PubMed

    Fernandes, Carlos A H; Pazin, Wallance M; Dreyer, Thiago R; Bicev, Renata N; Cavalcante, Walter L G; Fortes-Dias, Consuelo L; Ito, Amando S; Oliveira, Cristiano L P; Fernandez, Roberto Morato; Fontes, Marcos R M

    2017-03-03

    Crotoxin (CTX) is the main neurotoxin found in Crotalus durissus rattlesnake venoms being composed by a nontoxic and non-enzymatic component (CA) and a toxic phospholipase A2 (CB). Previous crystallographic structures of CTX and CB provided relevant insights: (i) CTX structure showed a 1:1 molecular ratio between CA and CB, presenting three tryptophan residues in the CA/CB interface and one exposed to solvent; (ii) CB structure displayed a tetrameric conformation. This study aims to provide further information on the CTX mechanism of action by several biophysical methods. Our data show that isolated CB can in fact form tetramers in solution; however, these tetramers can be dissociated by CA titration. Furthermore, CTX exhibits a strong reduction in fluorescence intensity and lifetime compared with isolated CA and CB, suggesting that all tryptophan residues in CTX may be hidden by the CA/CB interface. By companying spectroscopy fluorescence and SAXS data, we obtained a new structural model for the CTX heterodimer in which all tryptophans are located in the interface, and the N-terminal region of CB is largely exposed to the solvent. Based on this model, we propose a toxic mechanism of action for CTX, involving the interaction of N-terminal region of CB with the target before CA dissociation.

  11. Results of animal studies suggest a nonlinear dose-response relationship for benzene effects

    SciTech Connect

    Parodi, S.; Taningher, M. ); Lutz, W.K. ); Colacci, A.; Mazzullo, M.; Grilli, S. )

    1989-07-01

    Considering the very large industrial usage of benzene, studies in risk assessment aimed at the evaluation of carcinogenic risk at low levels of exposure are important. Animal data can offer indications about what could happen in humans and provide more diverse information than epidemiological data with respect to dose-response consideration. The authors have considered experiments investigating metabolism, short-term genotoxicity tests, DNA adduct formation, and carcinogenicity long-term tests. According to the different experiments, a saturation of benzene metabolism and benzene effects in terms of genotoxicity seems evident above 30 to 100 ppm. Below 30 to 60 ppm the initiating effect of benzene seems to be linear for a large interval of dosages, at least judging from DNA adduct formation. Potential lack of a promoting effect of benzene (below 10 ppm) could generate a sublinear response at nontoxic levels of exposure. This possibility was suggested by epidemiological data in humans and is not confirmed or excluded by their observations with animals.

  12. Biophysical studies suggest a new structural arrangement of crotoxin and provide insights into its toxic mechanism

    PubMed Central

    Fernandes, Carlos A. H.; Pazin, Wallance M.; Dreyer, Thiago R.; Bicev, Renata N.; Cavalcante, Walter L. G.; Fortes-Dias, Consuelo L.; Ito, Amando S.; Oliveira, Cristiano L. P.; Fernandez, Roberto Morato; Fontes, Marcos R. M.

    2017-01-01

    Crotoxin (CTX) is the main neurotoxin found in Crotalus durissus rattlesnake venoms being composed by a nontoxic and non-enzymatic component (CA) and a toxic phospholipase A2 (CB). Previous crystallographic structures of CTX and CB provided relevant insights: (i) CTX structure showed a 1:1 molecular ratio between CA and CB, presenting three tryptophan residues in the CA/CB interface and one exposed to solvent; (ii) CB structure displayed a tetrameric conformation. This study aims to provide further information on the CTX mechanism of action by several biophysical methods. Our data show that isolated CB can in fact form tetramers in solution; however, these tetramers can be dissociated by CA titration. Furthermore, CTX exhibits a strong reduction in fluorescence intensity and lifetime compared with isolated CA and CB, suggesting that all tryptophan residues in CTX may be hidden by the CA/CB interface. By companying spectroscopy fluorescence and SAXS data, we obtained a new structural model for the CTX heterodimer in which all tryptophans are located in the interface, and the N-terminal region of CB is largely exposed to the solvent. Based on this model, we propose a toxic mechanism of action for CTX, involving the interaction of N-terminal region of CB with the target before CA dissociation. PMID:28256632

  13. Snapshots of lignin oxidation and depolymerization in archaeological wood: an EGA-MS study.

    PubMed

    Tamburini, Diego; Łucejko, Jeannette Jacqueline; Ribechini, Erika; Colombini, Maria Perla

    2015-10-01

    Evolved gas analysis-mass spectrometry (EGA-MS) was used for the first time to study archaeological wood, in order to investigate its chemical degradation. The archaeological wood was from an oak pile from a stilt house found in the Neolithic 'La Marmotta' village (Lake Bracciano, Rome, Italy). The sampling was performed from the external to the internal part of the pile, following the annual growth rings in groups of five. In addition, sound oak wood and isolated wood components (holocellulose and cellulose) were also analyzed, and the results were used to highlight differences because of degradation. Our study demonstrated that EGA-MS provides information on the thermo-chemistry of archaeological wood along with in-depth compositional data thanks to the use of MS. Our investigations not only highlighted wood degradation in terms of differences between carbohydrates and lignin content, but also showed that lignin oxidation and depolymerization took place in the archaeological wood. Mass spectral data revealed differences among the archaeological samples from the internal to the external part of the pile. An increase in the formation of wood pyrolysis products bearing a carbonyl group at the benzylic position and a decrease in the amount of lignin dimers were observed. These were related to oxidation and depolymerization reactions, respectively.

  14. Microbiota studies in the bile duct strongly suggest a role for Helicobacter pylori in extrahepatic cholangiocarcinoma.

    PubMed

    Avilés-Jiménez, F; Guitron, A; Segura-López, F; Méndez-Tenorio, A; Iwai, S; Hernández-Guerrero, A; Torres, J

    2016-02-01

    Biliary tract cancer or extrahepatic cholangiocarcinoma (ECCA) represents the sixth commonest cause of cancer in the gastrointestinal tract in western countries. We aimed to characterize the microbiota and its predicted associated functions in the biliary tract of ECCA and benign biliary pathology (BBP). Samples were taken from 100 patients with ECCA and 100 patients with BBP by endoscopic cholangio-pancreatography for DNA extraction. Ten patients with ECCA and ten with BBP were selected for microbiota studies using the V4-16S rRNA gene and sequenced in Illumina platform. Microbiota analyses included sample-to-sample distance metrics, ordination/clustering and prediction of functions. Presence of Nesterenkonia sp. and Helicobacter pylori cagA and vacA genes were tested in the 100 ECCA and 100 BBP samples. Phylum Proteobacteria dominated all samples (60.4% average). Ordination multicomponent analyses showed significant microbiota separation between ECCA and BBP (p 0.010). Analyses of 4002 operational taxonomic units with presence variation in at least one category probed a separation of ECCA from BBP. Among these, Nesterenkonia decreased, whereas Methylophilaceae, Fusobacterium, Prevotella, Actinomyces, Novosphingobium and H. pylori increased in ECCA. Predicted associated functions showed increased abundance of H. pylori virulence genes in ECCA. cagA and vacA genes were confirmed by PCR in ECCA and BBP samples. This is the first microbiota report in ECCA and BBP to show significant changes in microbial composition. Bacterial species unusual for human flora were found: Methylophilaceae and Nesterenkonia are reported in hypersaline soils, and Mesorhizobium is a nitrogen-fixing bacterium. Enrichment of virulence genes confirms previous studies suggesting that H. pylori might be associated with ECCA.

  15. Interlaboratory study characterizing a yeast performance standard for benchmarking LC-MS platform performance.

    PubMed

    Paulovich, Amanda G; Billheimer, Dean; Ham, Amy-Joan L; Vega-Montoto, Lorenzo; Rudnick, Paul A; Tabb, David L; Wang, Pei; Blackman, Ronald K; Bunk, David M; Cardasis, Helene L; Clauser, Karl R; Kinsinger, Christopher R; Schilling, Birgit; Tegeler, Tony J; Variyath, Asokan Mulayath; Wang, Mu; Whiteaker, Jeffrey R; Zimmerman, Lisa J; Fenyo, David; Carr, Steven A; Fisher, Susan J; Gibson, Bradford W; Mesri, Mehdi; Neubert, Thomas A; Regnier, Fred E; Rodriguez, Henry; Spiegelman, Cliff; Stein, Stephen E; Tempst, Paul; Liebler, Daniel C

    2010-02-01

    Optimal performance of LC-MS/MS platforms is critical to generating high quality proteomics data. Although individual laboratories have developed quality control samples, there is no widely available performance standard of biological complexity (and associated reference data sets) for benchmarking of platform performance for analysis of complex biological proteomes across different laboratories in the community. Individual preparations of the yeast Saccharomyces cerevisiae proteome have been used extensively by laboratories in the proteomics community to characterize LC-MS platform performance. The yeast proteome is uniquely attractive as a performance standard because it is the most extensively characterized complex biological proteome and the only one associated with several large scale studies estimating the abundance of all detectable proteins. In this study, we describe a standard operating protocol for large scale production of the yeast performance standard and offer aliquots to the community through the National Institute of Standards and Technology where the yeast proteome is under development as a certified reference material to meet the long term needs of the community. Using a series of metrics that characterize LC-MS performance, we provide a reference data set demonstrating typical performance of commonly used ion trap instrument platforms in expert laboratories; the results provide a basis for laboratories to benchmark their own performance, to improve upon current methods, and to evaluate new technologies. Additionally, we demonstrate how the yeast reference, spiked with human proteins, can be used to benchmark the power of proteomics platforms for detection of differentially expressed proteins at different levels of concentration in a complex matrix, thereby providing a metric to evaluate and minimize pre-analytical and analytical variation in comparative proteomics experiments.

  16. Validation Study on a Rapid Method for Simultaneous Determination of Pesticide Residues in Vegetables and Fruits by LC-MS/MS.

    PubMed

    Sato, Tamaki; Miyamoto, Iori; Uemura, Masako; Nakatani, Tadashi; Kakutani, Naoya; Yamano, Tetsuo

    2016-01-01

    A validation study was carried out on a rapid method for the simultaneous determination of pesticide residues in vegetables and fruits by LC-MS/MS. Preparation of the test solution was performed by a solid-phase extraction technique with QuEChERS (STQ method). Pesticide residues were extracted with acetonitrile using a homogenizer, followed by salting-out and dehydration at the same time. The acetonitrile layer was purified with C18 and PSA mini-columns. The method was assessed for 130 pesticide residues in 14 kinds of vegetables and fruits at the concentration level of 0.01 μg/g according to the method validation guideline of the Ministry of Health, Labour and Welfare of Japan. As a result 75 to 120 pesticide residues were determined satisfactorily in the tested samples. Thus, this method could be useful for a rapid and simultaneous determination of multi-class pesticide residues in various vegetables and fruits.

  17. Comprehensive Proteomic Study of the Antiproliferative Activity of a Polyphenol-Enriched Rosemary Extract on Colon Cancer Cells Using Nanoliquid Chromatography-Orbitrap MS/MS.

    PubMed

    Valdés, Alberto; Artemenko, Konstantin A; Bergquist, Jonas; García-Cañas, Virginia; Cifuentes, Alejandro

    2016-06-03

    In this work, a proteomics strategy based on nanoliquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) using an Orbitrap high-resolution mass spectrometer together with stable isotope dimethyl labeling (DML) is applied to quantitatively examine relative changes in the protein fraction of HT-29 human colon cancer cells treated with different concentrations of a polyphenol-enriched rosemary extract over the time. The major objective of this study was to gain insights into the antiproliferative mechanisms induced by rosemary polyphenols. Using this methodology, 1909 and 698 proteins were identified and quantified in cell extracts. The polyphenol-enriched rosemary extract treatment changed the expression of several proteins in a time- and concentration-dependent manner. Most of the altered proteins are implicated in the activation of Nrf2 transcription factor and the unfolded protein response. In conclusion, rosemary polyphenols induced proteomic changes that were related to the attenuation of aggresome formation and activation of autophagy to alleviate cellular stress.

  18. UFLC-MS/MS determination and pharmacokinetic studies of six Saikosaponins in rat plasma after oral administration of Bupleurum Dropping Pills.

    PubMed

    Guan, Xiufeng; Wang, Xiangyang; Yan, Kaijing; Chu, Yang; Li, Shuming; Li, Wei; Yan, Xueying; Ma, Xiaohui; Zhou, Shuiping; Sun, He; Liu, Changxiao

    2016-05-30

    A rapid and sensitive ultra fast liquid chromatography tandem mass spectrometry method (UFLC-MS/MS) was developed and validated for the simultaneous determination of six Saikosaponins (SSs) (SSa, SSb1, SSb2, SSd, SSc, SSf) of Bupleurum Dropping Pills (BDP) in rat plasma using chloramphenicol as the internal standard (IS). The SSs were separated using an ACQUITY UPLC(®) BEH C18 column (50 mm × 2.1mm, 1.7 μm) and detection of these compounds were done by using a Qtrap 5500 mass spectrometer coupled with negative electrospray ionization (ESI) source under the multiple reaction monitoring (MRM) mode. According to regulatory guidelines, the established method was fully validated and results were showed within acceptable limits. The lower limit of quantifications (LLOQs) of all analytes were 0.2 ng/mL. The validated method was successfully applied into a pharmacokinetic study of orally administered BDP in rats.

  19. In vivo and in vitro hyperbaric studies in mice suggest novel sites of action for ethanol.

    PubMed

    Davies, D L; Bolger, M B; Brinton, R D; Finn, D A; Alkana, R L

    1999-02-01

    The present study uses increased atmospheric pressure as an ethanol antagonist to test the hypothesis that allosteric coupling pathways in the GABA(A) receptor complex represent initial sites of action for ethanol. This was accomplished using behavioral and in vitro measures to determine the effects of pressure on ethanol and other GABAergic drugs in C57BL/6 and LS mice. Behaviorally, exposure to 12 times normal atmospheric pressure (ATA) of a helium-oxygen gas mixture (heliox) antagonized loss of righting reflex (LORR) induced by the allosteric modulators ethanol and pentobarbital, but did not antagonize LORR induced by the direct GABA agonist 4,5,6,7-tetrahydroisoxazolo-pyridin-3-ol (THIP). Similarly, exposure to 12 ATA heliox antagonized the anticonvulsant effects verses isoniazid of ethanol, diazepam and pentobarbital. Biochemically, exposure to 12 ATA heliox antagonized potentiation of GABA-activated 36Cl-uptake by ethanol, flunitrazepam and pentobarbital in LS mouse brain preparations, but did not alter GABA-activated 36Cl- uptake per se. In contrast to its antagonist effect versus other allosteric modulators, pressure did not antagonize these behavioral or in vitro effects induced by the neuroactive steroid, 3alpha-hydroxy-5beta-pregnan-20-one (3alpha,5beta-P). These findings add to evidence that pressure directly and selectively antagonizes drug effects mediated through allosteric coupling pathways. The results fit predictions, and thus support the hypothesis that allosteric coupling pathways in GABA(A) receptors represent initial sites of action for ethanol. Collectively, the results suggest that there may be common physicochemical and underlying structural characteristics that define ethanol sensitive regions of receptor proteins and/or their associated membranes that can be identified by pressure within (e.g., GABA(A)) and possibly across (e.g., GABA(A), NMDA, 5HT3) receptors.

  20. PTR-MS study of esters in water and water/ethanol solutions

    NASA Astrophysics Data System (ADS)

    Aprea, Eugenio; Biasioli, Franco; Märk, Tilmann D.; Gasperi, Flavia

    2007-04-01

    Esters strongly influence the perceived aroma of alcoholic beverages and their rapid monitoring can play an important role in the quality control of these products. Proton transfer reaction mass spectrometry (PTR-MS) allows the rapid and non invasive monitoring of foodstuff but there is still a lack of information about the proton transfer induced fragmentation and on the effect of high ethanol concentration. PTR-MS fragmentation patterns of 21 esters are reported, most of them for the first time. For linear methyl and ethyl esters the fragmentation dependence on E/N was also evaluated. Acetate esters, with exception of methyl acetate, show as main peaks the characteristic fragment ions at m/z 61 and m/z 43, whereas propanoate esters, but methyl propanoate, exhibit as main peaks the typical signals at m/z 75 and m/z 57. For all the other esters, here reported, the spectra are dominated by the protonated molecular ion. For methyl and ethyl esters we also report, in many cases for the first time, the water-solution/air partition coefficients (Henry's law constant) and the ethanol-solution/air partition coefficients at different ethanol concentrations. The information provided in this work may be useful as a basis for further studies for the identification and quantification of esters in the headspace of alcoholic beverages extending the application field of PTR-MS.

  1. MALDI MS sample preparation by using paraffin wax film: systematic study and application for peptide analysis.

    PubMed

    Wang, Junhua; Chen, Ruibing; Ma, Mingming; Li, Lingjun

    2008-01-15

    Recently developed sample preparation techniques employing hydrophobic sample support have improved the detection sensitivity and mass spectral quality of matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). These methods concentrate the samples on target by minimizing the sample area via the solvent repellent effect of the target surface. In the current study, we employed the use of paraffin wax film (Parafilm M) for improved MALDI MS analysis of low-abundance peptide mixtures, including neuronal tissue releasate and protein tryptic digests. This thin film was found to strongly repel polar solvents including water, methanol, and acetonitrile, which enabled the application of a wide range of sample preparation protocols that involved the use of various organic solvents. A "nanoliter-volume deposition" technique employing a capillary column has been used to produce tiny ( approximately 400 microm) matrix spots of 2,5-dihydroxybenzoic acid on the film. By systematically optimizing the sample volume, solvent composition, and film treatment, the Parafilm M substrate in combination with the nanoliter-volume matrix deposition method allowed dilute sample to be concentrated on the film for MALDI MS analysis. Peptide mixtures with nanomolar concentrations have been detected by MALDI time-of-flight and MALDI Fourier transform ion cyclotron resonance mass spectrometers. Overall, the use of Parafilm M enabled improved sensitivity and spectral quality for the analysis of complex peptide mixtures.

  2. Current biochemical studies of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis suggest a new therapeutic approach.

    PubMed

    Hookman, Perry; Barkin, Jamie S

    2003-09-01

    . The feeding protocol was repeated with a second group of 18 ob/ob mice. After 4 wk, hepatocytes were obtained by in situ liver perfusion with collagenase and assayed for cellular adenosine triphosphate (ATP) content. In each experiment, hepatocytes isolated from 3 mice from each treatment group were suspended in a medium and pooled for subsequent analysis to evaluate cell viability, determine the number of obtained cells, and to assay cellular ATP content. These experiments were repeated using another 3 mice from each treatment group, so that analysis of hepatocytes took place from six ob/ob mice in each feeding group.Hepatic steatosis was decreased significantly only in the metformin-treated group. The authors found that metformin's beneficial effect on the fatty liver disease of mice was not due to its ability to constrain hyperphagia, nor due to decreased caloric ingestion, because the daily caloric intakes of the metformin-treated mice and the pair-fed control mice were virtually identical. These caloric intakes were consistently approximately 20% less than that of another obese control group that was permitted to consume diet ad libitum. The authors also observed no significant effect of metformin on serum glucose concentration from fed, ob/ob mice. Metformin is known to reduce hyperinsulinemia by about 40% in both of these obese hyperinsulinemic and insulin-resistant rodent strains. In conclusion, Lin et al. documented that metformin improves fatty liver disease and reverses hepatomegaly, steatosis, and aminotransferase abnormalities in mice. In addition, the authors suggest that metformin might inhibit dieting-induced redistribution of lipid from the liver to adipose tissue depots. In summary, this study identifies a potential treatment for fatty liver disease in humans.

  3. Longitudinal Study of Vision and Retinal Nerve Fiber Layer Thickness in MS

    PubMed Central

    Talman, Lauren S.; Bisker, Esther R.; Sackel, David J.; Long, David A.; Galetta, Kristin M.; Ratchford, John N.; Lile, Deacon J.; Farrell, Sheena K.; Loguidice, Michael J.; Remington, Gina; Conger, Amy; Frohman, Teresa C.; Jacobs, Dina A.; Markowitz, Clyde E.; Cutter, Gary R.; Ying, Gui-Shuang; Dai, Yang; Maguire, Maureen G.; Galetta, Steven L.; Frohman, Elliot M.; Calabresi, Peter A.; Balcer, Laura J.

    2010-01-01

    Objective Cross-sectional studies of optical coherence tomography (OCT) show that retinal nerve fiber layer (RNFL) thickness is reduced in multiple sclerosis (MS) and correlates with visual function. We determined how longitudinal changes in RNFL thickness relate to visual loss. We also examined patterns of RNFL thinning over time in MS eyes with and without a prior history of acute optic neuritis (ON). Methods Patients underwent OCT measurement of RNFL thickness at baseline and at 6-month intervals during a mean follow-up of 18 months at three centers. Low-contrast letter acuity (2.5%, 1.25% contrast) and visual acuity (VA) were assessed. Results Among 299 patients (593 eyes) with ≥6 months follow-up, eyes with visual loss showed greater RNFL thinning compared to eyes with stable vision (low-contrast acuity, 2.5%: p<0.001; VA: p=0.005). RNFL thinning increased over time, with average losses of 2.9 μm at 2-3 years and 6.1 μm at 3-4.5 years (p<0.001 vs. 0.5-1-year follow-up interval). These patterns were observed for eyes with or without prior history of ON. Proportions of eyes with RNFL loss greater than test-retest variability (≥6.6 μm) increased from 11% at 0-1 year to 44% at 3-4.5 years (p<0.001). Interpretation Progressive RNFL thinning occurs as a function of time in some patients with MS, even in the absence of ON, and is associated with clinically significant visual loss. These findings are consistent with sub-clinical axonal loss in the anterior visual pathway in MS and support the use of OCT and low-contrast acuity as methods to evaluate the effectiveness of putative neuroprotection protocols. PMID:20517936

  4. Highly sensitive LC-MS/MS-ESI method for determination of phenelzine in human plasma and its application to a human pharmacokinetic study.

    PubMed

    Kallem, Raja Reddy; Jillela, Bhupathi; Ravula, Arun Reddy; Samala, Ramakrishna; Andy, Adinarayana; Ramesh, Mullangi; Rao, Jvln Seshagiri

    2016-06-01

    A selective, sensitive and rapid LC-MS/MS method has been developed and validated for quantification of the phenelzine (PZ) in 200μL of human plasma using hydroxyzine (HZ) as an internal standard (IS) as per regulatory guidelines. The sample preparation involved the derivatization of PZ using pentaflurobenzaldehyde followed by solid phase extraction process to extract PZ and HZ from human plasma. LC-MS/MS was operated under the multiple reaction-monitoring mode (MRM) using the electro spray ionization technique in positive ion mode and the transitions of m/z 305.1→105.1 and m/z 375.3→201.1 were used to measure the derivative of PZ and IS, respectively. The total run time was 3.5min and the elution of PZ and HZ occurred at 2.53, and 1.92min, respectively; this was achieved with a mobile phase consisting of 10mM ammonium acetate: acetonitrile (20:80, v/v) at a flow rate of 1.0mL/min on an Ace C18 column with a split ratio of 70:30. The developed method was validated in human plasma with a lower limit of quantitation 0.51ng/mL. A linear response function was established for the range of concentrations 0.51-25.2ng/mL (r>0.995) for PZ. The intra- and inter-day precision values met the acceptance criteria. PZ was stable in the battery of stability studies viz., stock solution, bench-top, auto-sampler, long-term and freeze/thaw cycles. The developed assay method was applied to an oral bioequivalence study in humans.

  5. Simultaneous determination of nimesulide and its four possible metabolites in human plasma by LC-MS/MS and its application in a study of pharmacokinetics.

    PubMed

    Sun, Xiao; Xue, Kai-Lu; Jiao, Xin-Yue; Chen, Qian; Xu, Li; Zheng, Heng; Ding, Yu-Feng

    2016-08-01

    In this study, it was the first time that we simultaneously quantified nimesulide and its possible metabolites M1, M2, M3 and M4 by employing liquid chromatography-tandem mass spectrometry (LC-MS/MS). Nimesulide-d5 was used as internal standard (IS) for validation. Analytes and IS were recovered from human plasma by protein precipitation with acetonitrile. Prepared plasma samples were analyzed under the same LC-MS/MS conditions, and chromatographic separation was realized by using an Ultimate C18 column, with run time being 5min for each sample. Our results showed that various analytes within their concentration ranges could be quantified accurately by using the method. Mean intra- and inter-day accuracies ranged from -4.8% to 4.8% (RE), and intra- and inter-assay precision ≤6.2% (RSD). The following parameters were validated: specificity, recovery, matrix effects, dilution integrity, carry-over, sample stability under a variety of storage and handling conditions (room temperature, freezer, freeze-thaw and post-preparative) and stock solution stability. Pharmacokinetics of nimesulide and its metabolites were calculated based on the analysis of samples collected from twelve Chinese healthy volunteers after single oral dose of 100mg nimesulide tablets. By applying the pharmacokinetic determination into human samples, we preliminarily detected a new metabolite of nimesulide (M4*), and the concentration of M4* was relatively higher in plasma. Furthermore, we predicted part of conceivable metabolism pathway in plasma of after oral administration of 100mg nimesulide tablets. This research provided an experimental basis for further studies on metabolic activation and biotransformation of nimesulide, and for more comprehensive conjecture of its metabolic pathways.

  6. Physiological and Thermal Responses of MS Patients to Head and Vest Cooling: A Case Study

    NASA Technical Reports Server (NTRS)

    Luna, Bernadette; Webbon, Bruce W.; Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Kliss, Mark (Technical Monitor)

    1997-01-01

    Personal cooling systems are used to alleviate symptoms of multiple sclerosis (MS) and to prevent increased core temperature during daily activities. The objective of this study was to determine the operating characteristics and the physiologic changes produced by short term application of the stationary thermal control system used by most clinical institutions. The Life Enhancement Tech (LET) Mark VII portable cooling system and a lightweight Head-vest active cooling garment were used to cool the head and chest regions of 4 male and 3 female MS patients (30 to 66 yrs. old) in this study. The subjects, seated in an upright position at normal room temperature (approx. 24 C), were tested for 60 min. with the liquid cooling garment (LCG) operated at 50 F. Oral, right and left ear temperatures and cooling system parameters were logged manually every 5 min. Arm, leg, chest and rectal temperatures, heart rate, respiration, and an activity index were recorded continuously on a U.F.I., Inc., Biolog ambulatory monitor. All temperature responses showed extreme variation among subjects. The cold-sensitive subject's rectal temperature increased initially in response to cooling; the heat sensitive subject's rectal temperature decreased. After 40 min. of cooling and during recovery, all subjects'rectal temperatures decreased. Oral temperatures began to decrease after 30 min. of cooling. After 60 min. of cooling, temperature drops ranged from approx. 0.3 - 0.8 C. Oral temperatures continued to decrease during recovery (approx. 0.2 C). The car temperature of the heat sensitive subject was increased after cooling, other subjects exhibited an ear temperature decrease (0.0 - 0.5 C). These data indicate that head and vest cooling may be used to reduce the oral temperatures of MS patients by the approximate amount needed for symptomatic relief as shown by other researchers. The combination of a small subject population and a large subject variance does not permit us to draw statistical

  7. Genome-wide association studies suggest sex-specific loci associated with abdominal and visceral fat

    PubMed Central

    Sung, Yun Ju; Pérusse, Louis; Sarzynski, Mark A.; Fornage, Myriam; Sidney, Steve; Sternfeld, Barbara; Rice, Treva; Terry, Gregg; Jacobs, David R.; Katzmarzyk, Peter; Curran, Joanne E; Carr, John Jeffrey; Blangero, John; Ghosh, Sujoy; Després, Jean-Pierre; Rankinen, Tuomo; Rao, D.C.; Bouchard, Claude

    2015-01-01

    Background To identify loci associated with abdominal fat and replicate prior findings, we performed genome-wide association (GWA) studies of abdominal fat traits: subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), total adipose tissue (TAT) and visceral to subcutaneous adipose tissue ratio (VSR). Subjects and Methods Sex-combined and sex-stratified analyses were performed on each trait with (TRAIT-BMI) or without (TRAIT) adjustment for BMI, and cohort-specific results were combined via a fixed effects meta-analysis. A total of 2,513 subjects of European descent were available for the discovery phase. For replication, 2,171 European Americans and 772 African Americans were available. Results A total of 52 SNPs encompassing 7 loci showed suggestive evidence of association (p < 1.0 × 10−6) with abdominal fat in the sex-combined analyses. The strongest evidence was found on chromosome 7p14.3 between a SNP near BBS9 gene and VAT (rs12374818; p= 1.10 × 10−7), an association that was replicated (p = 0.02). For the BMI-adjusted trait, the strongest evidence of association was found between a SNP near CYCSP30 and VAT-BMI (rs10506943; p= 2.42 × 10−7). Our sex-specific analyses identified one genome-wide significant (p < 5.0 × 10−8) locus for SAT in women with 11 SNPs encompassing the MLLT10, DNAJC1 and EBLN1 genes on chromosome 10p12.31 (p = 3.97 × 10−8 to 1.13 × 10−8). The THNSL2 gene previously associated with VAT in women was also replicated (p= 0.006). The six gene/loci showing the strongest evidence of association with VAT or VAT-BMI were interrogated for their functional links with obesity and inflammation using the Biograph knowledge-mining software. Genes showing the closest functional links with obesity and inflammation were ADCY8 and KCNK9, respectively. Conclusions Our results provide evidence for new loci influencing abdominal visceral (BBS9, ADCY8, KCNK9) and subcutaneous (MLLT10/DNAJC1/EBLN1) fat, and confirmed a locus (THNSL2

  8. A Study of the Variation in the Salivary Peptide Profiles of Young Healthy Adults Acquired Using MALDI-TOF MS

    PubMed Central

    Brand, Henk; Imangaliyev, Sultan; Tsivtsivadze, Evgeni; van der Weijden, Fridus; de Jong, Ad; Paauw, Armand; Crielaard, Wim; Keijser, Bart; Veerman, Enno

    2016-01-01

    A cross-sectional observational study was conducted to evaluate the inter-individual variation in the MALDI-TOF MS peptide profiles of unstimulated whole saliva in a population of 268 systemically healthy adults aged 18–30 yr (150 males and 118 females) with no apparent caries lesions or periodontal disease. Using Spectral Clustering, four subgroups of individuals were identified within the study population. These subgroups were delimited by the pattern of variation in 9 peaks detected in the 2–15 kDa m/z range. An Unsupervised Feature Selection algorithm showed that P-C peptide, a 44 residue-long salivary acidic proline-rich protein, and three of its fragments (Fr. 1–25, Fr. 15–35 and Fr. 15–44) play a central role in delimiting the subgroups. Significant differences were found in the salivary biochemistry of the subgroups with regard to lysozyme and chitinase, two enzymes that are part of the salivary innate defense system (p < 0.001). These results suggest that MALDI-TOF MS salivary peptide profiles may relate information on the underlying state of the oral ecosystem and may provide a useful reference for salivary disease biomarker discovery studies. PMID:27258023

  9. Simultaneous determination of the bioactive components in rat plasma by UPLC-MS/MS and application in pharmacokinetic studies after oral administration of Radix scutellariae extract.

    PubMed

    Tao, Jin-Hua; Xu, Jun; Jiang, Shu; Ling, Yong; Wang, Dong-Geng

    2017-02-16

    A highly sensitive and rapid ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed and validated for simultaneous quantification of the four main bioactive compounds, i.e., baicalin, baicalein, wogonoside and wogonin in rat plasma after oral administration of Radix scutellariae extract. Clarithromycin was used as an internal standard (IS). Plasma samples were processed by protein precipitation with methanol. The separation was performed on an Acquity BEH C18 column (100 mm × 2.1 mm, 1.7 µm) at a flow rate of 0.4 mL/min, using 0.1% formic acid-acetonitrile as mobile phase. The MS/MS ion transit ions monitored were 447.5 → 270.1 for baicalin, 270.1 → 168.1 for baicalein, 461.2 → 284.0 for wogonoside, 284.2 → 168.1 for wogonin and 748.5 → 158.1 for IS. Method validation was performed according to Food and Drug Administration guidelines and the results met the acceptance criteria. The lower limit of quantification (LLOQ) achieved was 1.13 ng/mL for baicalin, 1.23 ng/mL for baicalein, 0.82 ng/mL for wogonoside and 0.36 ng/mL for wogonin, respectively. The calibration curves obtained were linear (r > 0.99) over the concentration range approximately 1-1000 ng/mL. The intra- and inter-day precision was less than 15% and the accuracy was within ±14.7%. After validation, this method was successfully applied to a pharmacokinetic study of Radix scutellariae extract.

  10. Development and validation of a LC-MS/MS method for D-cycloserine determination in human plasma for bioequivalence study.

    PubMed

    Yaroshenko, Dmitry V; Grigoriev, Alexander V; Sidorova, Alla A

    2014-01-01

    A reliable and high throughput high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and validated for determining levels of the antitubercular drug-D -cycloserine in human plasma. Plasma samples analyte with an internal standard (IS) (niacin) were prepared by solid-phase extraction using Waters Oasis MCX cartridges. The chromatographic separation was performed using the HILIC mode on a YMC-Pack SIL-06 column (150 × 4.6 mm; 3 μm) under isocratic conditions. The run time of analysis was 5 min. The mobile phase consisted of methanol, propanol-2 and 0.075 % trifluoroacetic acid (66.5:28.5:5, v/v/v). Protonated ions formed by turbo ion spray in positive mode were used to detect the analyte and the IS. MS/MS detection was used to monitor the fragmentation of 103-75 m/z for cycloserine and 124 to 80 m/z for niacin (IS) on an API 4000 (AB Sciex) triple quadrupole mass spectrometer. A linear dynamic range of 0.3-30 μg/mL was established for cycloserine using 0.2 mL human plasma and a 1 μL injection volume. The mean relative recovery of cycloserine and niacin were 77.2 and 82.4 %, respectively. The procedure of sample preparation was consistent and reproducible (precision, 0.8-3.4 %; accuracy, 93.8-104.9 %). The method was validated in accordance with requirements of the European Medicines Agency and successfully applied to a bioequivalence study of 250 mg tablet formulations in 23 healthy human subjects.

  11. Rapid and sensitive LC-MS/MS method for determination of megestrol acetate in human plasma: application to a human pharmacokinetic study.

    PubMed

    Seo, Ji-Hyung; Park, Ji-Sun; Jo, Min-Ho; Park, Mi-Sun; Ryu, Ju-Hee; Cho, Young-Wuk; Shim, Wang-Sup; Noh, Gyu-Jeong; Lee, Kyung-Tae

    2013-04-01

    A rapid, simple and fully validated LC-MS/MS method was developed and validated for the determination of megestrol acetate in human plasma using tolbutamide as an internal standard (IS) after one-step liquid-liquid extraction with methyl-tert-butyl-ether. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the transitions m/z 385.5 → 267.1 for megestrol acetate and m/z 271.4 → 155.1 for IS. Chromatographic separation was performed on a YMC Hydrosphere C18 column with an isocratic mobile phase, which consisted of 10 mm ammonium formate buffer (adjusted to pH 5.0 with formic acid)-methanol (60:40, v/v) at a flow rate of 0.4 mL/min. The achieved lower limit of quantitation (LLOQ) was 1 ng/mL (signal-to-noise ratio > 10) and the standard calibration curve for megestrol acetate was linear (r > 0.99) over the studied concentration range (1-2000 ng/mL). The proposed method was fully validated by determining its specificity, linearity, LLOQ, intra- and inter-day precision and accuracy, recovery, matrix effect and stability. The validated LC-MS/MS method was successfully applied for the evaluation of pharmacokinetic parameters of megestrol acetate after oral administration of a single dose 800 mg of megestrol acetate (Megace™) to five healthy Korean male volunteers under fed conditions.

  12. Development of a rapid and sensitive UPLC-MS/MS assay for the determination of TM-2 in beagle dog plasma and its application to a pharmacokinetic study.

    PubMed

    Lin, Hongli; Zhao, Yunli; Men, Lei; Yang, Mingjing; Liu, Hui; Shao, Yanjie; Wang, Pei; Tang, Xing; Yu, Zhiguo

    2015-01-01

    A simple and sensitive method based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed for the determination of TM-2, which was a novel semi-synthetic taxane derivative in beagle dog plasma. Cabazitaxel was chosen as internal standard. Following extraction by methyl tert-butyl ether, the chromatographic separation was achieved on a Thermo Syncronis C18 column (50 × 2.1 mm, 1.7 µm) by gradient elution within a runtime of 3.5 min. The mobile phase consisted of (A) acetonitrile and (B) 2 mmol/L ammonium acetate in water. The detection was accomplished using positive ion electrospray ionization in multiple reaction monitoring mode. The MS/MS ion transitions were monitored at m/z 812.39 → 551.35 for TM-2 and 836.36 → 555.26 for IS, respectively. The method was linear for TM-2 (r = 0.9924) ranging from 2.5 to 1000 ng/mL. The intra-day and inter-day precisions (relative standard deviation) were within 8.0 and 17.6%, respectively, and the accuracy (relative error) was less than 2.3%. The extraction recovery ranged from 83.1 to 97.1%. The reliable method was successfully applied to a pharmacokinetic study of TM-2 in beagle dogs after intravenous drip with different doses of 0.6, 1.2, and 2.4 mg/kg, respectively.

  13. Development of an LC-MS/MS method for studying migration characteristics of acetaldehyde in polyethylene terephthalate (PET)-packed mineral water.

    PubMed

    Baumjohann, Nina; Harms, Diedrich

    2015-01-01

    During storage, acetaldehyde migration from polyethylene terephthalate (PET) bottles can affect the quality of mineral water even in the low µg l(-1) range negatively, as it features a fruity or plastic-like off-flavour. For a sensitive and fast analysis of acetaldehyde in mineral water, a new analysis method of 2,4-dinitrophenylhydrazine (DNPH) derivatisation followed by HPLC-electrospray tandem mass spectrometry (ESI-MS/MS) was developed. Acetaldehyde was directly derivatised in the mineral water sample avoiding extraction and/or pre-concentration steps and then analysed by reversed-phase HPLC-ESI-MS/MS using multiple reaction monitoring mode (MRM). Along with method development, the optimum molar excess of DNPH in contrast to acetaldehyde was studied for the mineral water matrix, because no specific and robust data were yet available for this critical parameter. Best results were obtained by using a calibration via the derivatisation reaction. Without any analyte enrichment or extraction, an LOD of 0.5 µg l(-1) and an LOQ of 1.9 µg l(-1) were achieved. Using the developed method, mineral water samples packed in PET bottles from Germany were analysed and the correlation between the acetaldehyde concentration and other characteristics of the samples was evaluated illustrating the applicability of the method. Besides a relationship between bottle size and CO2 content of the mineral water and acetaldehyde migration, a correlation with acetaldehyde migration and the material composition of the bottle, e.g. recycled PET, was noted. Investigating the light influence on the acetaldehyde migration with a newly developed, reproducible light exposure setup, a significant increase of the acetaldehyde concentration in carbonated mineral water samples was observed.

  14. Degradation of alachlor in natural and sludge-amended soils, studied by gas and liquid chromatography coupled to mass spectrometry (GC-MS and HPLC-MS).

    PubMed

    Rodríguez-Cruz, Sonia; Lacorte, Silvia

    2005-11-30

    Alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] is an herbicide used worldwide. The relative rates of disappearance of alachlor, the formation kinetics of alachlor ethane sulfonic acid (ESA), and the formation of other degradation products in two different soils (a soil with natural organic matter and a sludge-amended soil) has been studied. For such a purpose, soil samples were spiked with alachlor at 2.5 mg kg(-1), concentration generally applied in agricultural soils, and were submitted to sunlight, simulating natural field conditions. Extracts were analyzed by GC-MS and HPLC-MS in scan mode. A good correlation was observed between both techniques, and HPLC-MS allowed the determination of two eluting peaks corresponding to the two stereoisomeric forms of alachlor ESA. Degradation of alachlor in the two soils followed first-order kinetics. Half-life in the natural soil was 4.2 +/- 0.1 days, and half-life in the sludge-amended soil was 5.8 +/- 0.8 days. The higher half-life observed in the sludge-amended soil was attributed to the higher sorption of alachlor to this soil compared to the natural soil. The degradation of alachlor in both soils gave rise to the production of alachlor ESA. Its concentration increased during the incubation period, and after 27 days, its concentration was about 0.59 mg kg(-1) in the natural soil and 0.37 mg kg(-1) in the sludge-amended soil. The other two alachlor transformation products were identified using GC-MS, and the abundance of these degradation products increased while alachlor was degraded.

  15. Preclinical Studies Suggest Complex Nutraceutical Strategies May Have Potential for Preventing and Managing Sepsis.

    PubMed

    McCarty, Mark F

    2015-01-01

    An analysis of signaling mechanisms triggered by toll receptor 4 (TLR4) in macrophages, as well as of pertinent cell-culture and rodent studies, suggests that various nutraceuticals may have clinical potential for preventing and treating Gram-negative sepsis. Endotoxin activation of TLR4 results in induction of nitric oxide synthase (iNOS); cyclooxygenase 2 (COX-2); tissue factor (TF); and a range of proinflammatory cytokines, such as tumor necrosis factor α (TNF-α), interleukin-1 β (IL-1β), and interleukin 6 (IL-6), that collaborate to generate the clinical picture of sepsis. Upstream activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase contributes importantly to those effects by inducing superoxide production that promotes activation of p38 mitogen-activated protein (MAP) kinase and nuclear factor (NF) κΒ. Bilirubin generated intracellularly by activation of heme oxygenase 1 (HO-1) functions to provide feedback inhibition of NAPDH-oxidase complexes. Exogenous bilirubin, or its precursor, biliverdin, is protective in rodent models of sepsis. One nutraceutical, phycocyanobilin (PhyCB), is a biliverdin derivative that functions as a light-gathering chromophore in cyanobacteria such as spirulina and can be converted intracellularly to a compound structurally homologous to bilirubin that likewise inhibits NADPH-oxidase complexes. In rodent studies, administration of phycocyanin, to which PhyCB is covalently attached, has likewise been shown to be protective in rodent models of sepsis. Other nutraceuticals provide benefits in counteracting the effects of TLR4. Phase 2-inductive nutraceuticals, such as lipoic acid, have the potential to induce HO-1 activity in macrophages, promoting bilirubin production. They may also antagonize the upregulatory impact of reactive oxygen species (ROS) on macrophage signaling by boosting glutathione synthesis. Another nutraceutical, glycine, helps counter the TLR4-triggered calcium influx that occurs through

  16. Humane Science Projects: Suggestions for Biology Studies That Are Scientifically Educational and Ethically Non-Controversial.

    ERIC Educational Resources Information Center

    Balcombe, Jonathan P., Comp.

    This paper lists 35 studies in biology which can be tailored to suit the full range of student age groups and are designed to involve most or all of the key elements of the scientific process (study design, data collection and presentation, and experimental manipulation). Examples of some studies are: (1) study the growth of molds on food items…

  17. Quantification of Lumefantrine in Human Plasma Using LC-MS/MS and Its Application to a Bioequivalence Study.

    PubMed

    Pingale, Satish G; Mangaonkar, Kiran V

    2013-01-01

    An analytical method based on protein precipitation has been developed and validated for analysis of lumefantrine in human plasma. Artesunate was used as an internal standard for lumefantrine. Inertsil ODS column provided chromatographic separation of analytes followed by detection with mass spectrometry. The method involves simple isocratic chromatographic condition and mass spectrometric detection in the positive ionization mode using an API-3000 system. The total run time was 2.5 minutes. The proposed method has been validated with linear range of 200-20000 ng/mL for lumefantrine. The intrarun and interrun precision values are within 6.66% and 5.56%, respectively, for lumefantrine at the lower limit of quantification level. The overall recovery for lumefantrine and artesunate was 93.16% and 91.05%, respectively. This validated method was used successfully for analysis of plasma samples from a bioequivalence study.

  18. Determination and validation of chikusetsusaponin IVa in rat plasma by UPLC-MS/MS and its application to pharmacokinetic study.

    PubMed

    Wang, Ying; Liu, Shi-Ping; Guo, Mei-Hua; Wang, Zhuo

    2016-09-01

    A novel, sensitive and rapid ultra-performance liquid chromatography-tandem mass spectrometric method for the quantification of chikusetsusaponin IVa (CHS-IVa) in rat plasma was established and validated. Plasma samples were pre-treated by precipitation of protein with acetonitrile and chromatographed on a Waters Symmetry C18 analytical column (4.6 × 50 mm, i.d., 3.5 μm) using a mobile phase consisting of methanol and water containing 0.05% formic acid (55:45, v/v) at a flow rate of 0.4 mL/min. The deprotonated molecular ions [M - H](-) were employed in electrospray negative ionization mode and selected reaction monitoring transitions were performed for detection. The calibration curves exhibited good linearity (r > 0.99) over the range of 0.5-1000 ng/mL for CHS-IVa. The recoveries of CHS-IVa were >92.5% and exhibited no severe matrix effect. This method was successfully applied in the pharmacokinetic study of CHS-IVa in rats. For oral administration, the plasma concentrations of CHS-IVa increased to a peak value at 0.35 ± 0.14 h, followed by a gradual decrease to the lower limit of quantitation in 24 h. For intravenous administration, the plasma concentrations of CHS-IVa decreased quickly (t1/2 , 1.59 ± 0.25 h). The absolute bioavailability of CHS-IVa in rats was 8.63%. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Beyond the initial 140 ms, lexical decision and reading aloud are different tasks: An ERP study with topographic analysis.

    PubMed

    Mahé, Gwendoline; Zesiger, Pascal; Laganaro, Marina

    2015-11-15

    Most of our knowledge on the time-course of the mechanisms involved in reading derived from electrophysiological studies is based on lexical decision tasks. By contrast, very few ERP studies investigated the processes involved in reading aloud. It has been suggested that the lexical decision task provides a good index of the processes occurring during reading aloud, with only late processing differences related to task response modalities. However, some behavioral studies reported different sensitivity to psycholinguistic factors between the two tasks, suggesting that print processing could differ at earlier processing stages. The aim of the present study was thus to carry out an ERP comparison between lexical decision and reading aloud in order to determine when print processing differs between these two tasks. Twenty native French speakers performed a lexical decision task and a reading aloud task with the same written stimuli. Results revealed different electrophysiological patterns on both waveform amplitudes and global topography between lexical decision and reading aloud from about 140 ms after stimulus presentation for both words and pseudowords, i.e., as early as the N170 component. These results suggest that only very early, low-level visual processes are common to the two tasks which differ in core processes. Taken together, our main finding questions the use of the lexical decision task as an appropriate paradigm to investigate reading processes and warns against generalizing its results to word reading.

  20. Development and validation of an LC-MS/MS method for the determination of tofogliflozin in plasma and its application to a pharmacokinetic study in rats.

    PubMed

    Kobuchi, Shinji; Matsuno, Megumi; Fukuda, Etsuko; Ito, Yukako; Sakaeda, Toshiyuki

    2016-08-01

    Tofogliflozin is a novel selective inhibitor of sodium-dependent glucose co-transporter-2 (SGLT2) and has been developed for the treatment of patients with type 2 diabetes mellitus. In this study, a highly sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitation of tofogliflozin in rat plasma was developed and validated. The detection was performed using an API 3200 triple-quadrupole mass spectrometer with selected reaction monitoring (SRM) in the positive electrospray ionization mode. The SRM transitions were m/z=387.1 [M+H](+)→267.1 for tofogliflozin and m/z=451.2 [M+H](+)→71.0 for empagliflozin (internal standard: I.S.). Chromatographic separation was performed on a Quicksorb ODS (2.1mm i.d.×150mm, 5μm size) using isocratic elution with acetonitrile/10mM ammonium acetate (50:50, v/v) as the mobile phase at a flow rate of 0.2mL/min and the total run time was 4.0min. The lower limit of quantification (LLOQ) for tofogliflozin was 0.5ng/mL with sufficient specificity, accuracy, and precision. The validated method was successfully applied to the pharmacokinetic studies of tofogliflozin in rats. This assay method could be a valuable tool for future studies including pharmacokinetic and pharmacodynamic studies of SGLT2 inhibitors.

  1. The Views and Suggestions of Social Studies Teachers about the Implementation of Drama Method

    ERIC Educational Resources Information Center

    Celikkaya, Tekin

    2014-01-01

    Associating knowledge with daily life leads to permanent knowledge, which increases students' success in school. Drama is viewed to be one of the most effective methods that serves a purpose, and many researchers have determined that this method must be included at all levels of education. There are not much studies on social studies teachers'…

  2. Spectral study of suggested Apollo sites. [proposals for financial support and the electronic spectra of pyroxenes

    NASA Technical Reports Server (NTRS)

    Mccord, T. B.

    1973-01-01

    The spectrophotometry (0.3 to 1.1 microns) of visited and proposed Apollo landing sites is presented along with proposals for financial support of the spectral study. The electronic spectra of pyroxenes is investigated along with an interpretation of telescopic spectral reflectivity curves of the moon. Reprints of published articles related to these studies are included.

  3. Reason for Cautious Optimism? Two Studies Suggesting Reduced Stigma Against Suicide

    PubMed Central

    Witte, Tracy K.; Smith, April R.; Joiner, Thomas E.

    2012-01-01

    We present data from two studies that aimed to investigate stigma against suicide. In Study 1, we employed Milgram et al.'s (1965) “lost letter” technique. We predicted that fewer letters addressed to a fictitious organization with the word “suicide” in its name would be returned than letters addressed to fictitious heart disease or diabetes organizations, presumably due to stigma. Contrary to expectation, there were no differences in the percentage of letters returned for each condition, despite power to detect small effects. In Study 2 we compared scores on the Suicide Opinion Questionnaire (SOQ; Domino, Gibson, Poling, & Westlake, 1980) from a study published in 1988 (Domino, MacGregor, & Hannah, 1988) to scores from a study conducted 19 years later. Results demonstrated reduced stigma toward suicide, with the belief that suicide is morally bad exhibiting the largest change. PMID:20455251

  4. A population-based study of aerococcal bacteraemia in the MALDI-TOF MS-era.

    PubMed

    Senneby, E; Göransson, L; Weiber, S; Rasmussen, M

    2016-05-01

    The purpose of this study was to determine the incidence of aerococcal bacteraemia in the MALDI-TOF MS-era, to describe the clinical presentation and to determine the MIC values of aerococci for ten antibiotics. Aerococci in blood cultures were identified through searches in the laboratory database for the years 2012-2014. MALDI-TOF MS, sequencing of the 16S rRNA gene and a PYR test were used for species identification. Patients' medical charts were systematically reviewed. Etests were used to determine MIC values. Seventy-seven patients were identified (Aerococcus urinae n = 49, Aerococcus viridans n = 14, Aerococcus sanguinicola n = 13 and Aerococcus christensenii n = 1) corresponding to incidences of 14 cases per 1,000,000 inhabitants per year (A. urinae) and 3.5 cases per 1,000,000 inhabitants per year (A. sanguinicola and A.viridans). A. urinae was in pure culture in 61 %, A. sanguinicola in 46 % and A. viridans in 36 % of the cases. The A. urinae and A. sanguinicola patients were old and many had urinary tract disorders, and a majority had a suspected urinary tract focus of the bacteraemia. Eighty percent of the A. urinae patients were men. Five A. urinae patients were diagnosed with infective endocarditis. Six patients died within 30 days. Most isolates had low MICs to penicillins and carbapenems. MALDI-TOF MS has led to an increased identification of aerococcal bacteremia. A. urinae remains the most common Aerococcus in blood cultures and in aerococcal IE.

  5. GC-MS determined cotinine in an epidemiological study on smoking status at delivery.

    PubMed

    Chazeron, Ingrid de; Daval, Sandrine; Ughetto, Sylvie; Richard, Damien; Nicolay, Alain; Lemery, Didier; Llorca, Pierre M; Coudoré, François

    2008-01-01

    The objective of this study was to measure the plasma cotinine levels in pregnant women and their newborns using a gas chromatography-mass spectrometry (GC-MS) method in an epidemiological-delivered population with a wide range of tobacco intakes. Nearly 1000 pregnant women from regional maternity wards (n=1007) were selected for the study. Each patient kept a tobacco diary and underwent a blood test to assess cotinine levels and at the same time that the newborns' cordonal plasma was taken. These values were then cross-checked. Cotinine was estimated using a selected-ion monitoring mode with a 1.5 ng/ml quantification limit. The cotinine levels in mothers and newborns were highly correlated, whatever the mother's smoking status, with a calculated cut-off for cotinine levels in active smokers of 21.5 ng/ml. Finally, the cotinine determined through this GC-MS method offered a sensitive and accurate measure of tobacco exposition of the pregnant women and their babies.

  6. Development and validation of a highly sensitive LC-MS/MS method for the determination of dexamethasone in nude mice plasma and its application to a pharmacokinetic study.

    PubMed

    Yuan, Yin; Zhou, Xuan; Li, Jian; Ye, Suofu; Ji, Xiwei; Li, Liang; Zhou, Tianyan; Lu, Wei

    2015-04-01

    In the current study, a simple, sensitive and rapid analytical method for the determination of dexamethasone was developed and applied to a pharmacokinetic study in nude mice. Using testosterone as an internal standard, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach after one-step precipitation with acetonitrile was validated and used to determine the concentrations of dexamethasone in nude mice plasma. The method utilized a simple isocratic reverse phase separation over a Dionex C18 column with a mobile phase composed of acetonitrile-water (40:60, v/v). The analyte was detected by a triple quadrupole tandem mass spectrometer via electrospray and multiple reaction monitoring was employed to select both dexamethasone at m/z 393.0/147.1 and testosterone at m/z 289.5/97.3 in the positive ion mode. The calibration curves were linear (r >0.99) ranging from 2.5 to 500 ng/mL with a lower limit of quantitation of 2.5 ng/mL. The relative standard deviation ranged from 1.69 to 9.22% while the relative error ranged from -1.92 to -8.46%. This method was successfully applied to a preclinical pharmacokinetic study of dexamethasone and its pharmacokinetics was characterized by a two-compartment model with first-order absorption in female nude mice.

  7. A fast, sensitive and simple method for mirtazapine quantification in human plasma by HPLC-ESI-MS/MS. Application to a comparative bioavailability study.

    PubMed

    Borges, Ney Carter; Barrientos-Astigarraga, Rafael Eliseo; Sverdloff, Carlos Eduardo; Donato, José Luiz; Moreno, Patricia; Felix, Leila; Galvinas, Paulo Alexandre Rebelo; Moreno, Ronilson Agnaldo

    2012-11-01

    In the present study a simple, fast, sensitive and robust method to quantify mirtazapine in human plasma using quetiapine as the internal standard (IS) is described. The analyte and the IS were extracted from human plasma by a simple protein precipitation with methanol and were analyzed by high-performance liquid chromatography coupled to an electrospray tandem triple quadrupole mass spectrometer (HPLC-ESI-MS/MS). Chromatography was performed isocratically on a C(18), 5 µm analytical column and the run time was 1.8 min. The lower limit of quantitation was 0.5 ng/mL and a linear calibration curve over the range 0.5-150 ng/mL was obtained, showing acceptable accuracy and precision. This analytical method was applied in a relative bioavailability study in order to compare a test mirtazapine 30 mg single-dose formulation vs a reference formulation in 31 volunteers of both sexes. The study was conducted in an open randomized two-period crossover design and with a 14 day washout period. Since the 90% confidence interval for C(max) , AUC(last) and AUC(0-inf) were within the 80-125% interval proposed by the Food and Drug Administration and ANVISA (Brazilian Health Surveillance Agency), it was concluded that mirtazapine 30 mg/dose is bioequivalent to the reference formulation, according to both the rate and extent of absorption.

  8. Removal of malathion from aqueous solution using De-Acidite FF-IP resin and determination by UPLC-MS/MS: equilibrium, kinetics and thermodynamics studies.

    PubMed

    Naushad, Mu; Alothman, Z A; Khan, M R

    2013-10-15

    In the present study, De-Acidite FF-IP resin was used to remove a highly toxic and persistent organophosphorus pesticide (malathion) from the aqueous solution. Batch experiments were performed as a function of various experimental parameters such as effect of pH (2-10), contact time (10-120 min), resin dose (0.05-0.5 g), initial malathion concentration (0.5-2.5 µg mL(-1)) and temperature (25-65°C). The concentration of malathion was determined using a sensitive, selective and rapid ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. The uptake rate of malathion on De-Acidite FF-IP resin was rapid and equilibrium established within 40 min. Kinetics studies showed better applicability for pseudo-second-order model. The equilibrium data was fitted to Langmuir and Freundlich isotherm models and the isotherm constants were calculated for malathion. The values of thermodynamic parameters (ΔG(0), ΔH(0) and ΔS(0)) were computed from the Van't Hoff plot of lnKC vs. 1/T which showed that the adsorption of malathion was feasible, endothermic and spontaneous. The regeneration studies were carried out which demonstrated a decrease in the recovery of malathion from 95% to 68% after five consecutive cycles. Breakthrough and exhaustive capacities of malathion were found to be 1.25 mg g(-1) and 3.5 mg g(-1), respectively.

  9. Molecular studies suggest that cartilaginous fishes have a terminal position in the piscine tree

    PubMed Central

    Rasmussen, Ann-Sofie; Arnason, Ulfur

    1999-01-01

    The Chondrichthyes (cartilaginous fishes) are commonly accepted as being sister group to the other extant Gnathostomata (jawed vertebrates). To clarify gnathostome relationships and to aid in resolving and dating the major piscine divergences, we have sequenced the complete mtDNA of the starry skate and have included it in phylogenetic analysis along with three squalomorph chondrichthyans—the common dogfish, the spiny dogfish, and the star spotted dogfish—and a number of bony fishes and amniotes. The direction of evolution within the gnathostome tree was established by rooting it with the most closely related non-gnathostome outgroup, the sea lamprey, as well as with some more distantly related taxa. The analyses placed the chondrichthyans in a terminal position in the piscine tree. These findings, which also suggest that the origin of the amniote lineage is older than the age of the oldest extant bony fishes (the lungfishes), challenge the evolutionary direction of several morphological characters that have been used in reconstructing gnathostome relationships. Applying as a calibration point the age of the oldest lungfish fossils, 400 million years, the molecular estimate placed the squalomorph/batomorph divergence at ≈190 million years before present. This dating is consistent with the occurrence of the earliest batomorph (skates and rays) fossils in the paleontological record. The split between gnathostome fishes and the amniote lineage was dated at ≈420 million years before present. PMID:10051614

  10. Molecular studies suggest that cartilaginous fishes have a terminal position in the piscine tree.

    PubMed

    Rasmussen, A S; Arnason, U

    1999-03-02

    The Chondrichthyes (cartilaginous fishes) are commonly accepted as being sister group to the other extant Gnathostomata (jawed vertebrates). To clarify gnathostome relationships and to aid in resolving and dating the major piscine divergences, we have sequenced the complete mtDNA of the starry skate and have included it in phylogenetic analysis along with three squalomorph chondrichthyans-the common dogfish, the spiny dogfish, and the star spotted dogfish-and a number of bony fishes and amniotes. The direction of evolution within the gnathostome tree was established by rooting it with the most closely related non-gnathostome outgroup, the sea lamprey, as well as with some more distantly related taxa. The analyses placed the chondrichthyans in a terminal position in the piscine tree. These findings, which also suggest that the origin of the amniote lineage is older than the age of the oldest extant bony fishes (the lungfishes), challenge the evolutionary direction of several morphological characters that have been used in reconstructing gnathostome relationships. Applying as a calibration point the age of the oldest lungfish fossils, 400 million years, the molecular estimate placed the squalomorph/batomorph divergence at approximately 190 million years before present. This dating is consistent with the occurrence of the earliest batomorph (skates and rays) fossils in the paleontological record. The split between gnathostome fishes and the amniote lineage was dated at approximately 420 million years before present.

  11. The stability of the suggested planet in the ν Octantis system: a numerical and statistical study

    NASA Astrophysics Data System (ADS)

    Quarles, Billy; Cuntz, Manfred; Musielak, Zdzislaw

    2012-03-01

    Exoplanets in binary systems have received heightened interest by the scientific community. Especially with the recent detection of a circumbinary planet of Kepler-16b (Doyle et al. 2011)[Science 333, 1602] planets in binary systems have warranted second and even third glances. The system of ν Octantis has been a system of great controversy since the suggested planet in this system (Ramm et al. 2009)[MNRAS 394, 1695] appears to be located beyond its theoretical stability limit. In order to resolve this controversy we seek to determine whether the proposed planet can exist in the context of current stability theory. We have performed detailed simulations by exploiting the uncertainty measurements to determine the short and long-term stability of a prograde starting configuration. However to follow up on the previous results by Eberle & Cuntz (2010)[ApJ 721, L168], we have investigated the hypothesis of a retrograde orbit in more detail by considering a larger set of possible initial conditions to determine the possibility of a retrograde configuration with respect to the motion of the binary system. We will show that a retrograde configuration is preferred by both stability considerations with respect to the maximum Lyapunov exponent and numerical statistical considerations.

  12. A quantitative LC-MS/MS method for determination of thiazolidinedione mitoNEET ligand NL-1 in mouse serum suitable for pharmacokinetic studies.

    PubMed

    Pedada, Kiran K; Zhou, Xiang; Jogiraju, Harini; Carroll, Richard T; Geldenhuys, Werner J; Lin, Li; Anderson, David J

    2014-01-15

    Thiazolidinedione (TZD) compounds have shown promise as antidiabetic, antibiotics, antifungal and neuroprotective agents. The mitochondrial effect of a novel mitoNEET ligand, NL-1 {5-[(3,5-di-tert-butyl-4-hydroxyphenyl)methyl]-1,3-thiazolidine-2,4-dione}, and other TZD compounds, is a newly proposed mechanism for the neuroprotective action of these TZD compounds. In this work, a sensitive LC-MS/MS assay has been developed and validated for quantification of NL-1 in mouse serum. Sample preparation involved an acetonitrile protein precipitation procedure with addition of an internal standard NL-2 {5-[(4-hydroxy-3,5-dimethyl-phenyl)methyl]thiazolidine-2,4-dione}. LC-MS/MS analysis utilized a Columbus C-18 HPLC column (2mm×50mm, 5μm). Chromatography employed a multiple step gradient program that featured a steep linear gradient (25-95% in 0.5min) of 15μM ammonium acetate (additive for eliminating carry-over) in 2% methanol mixing with increasing proportions of 100% methanol. The HPLC was interfaced to a QTrap 5500 mass spectrometer (AB Sciex) equipped with an electrospray ionization source used in a negative ionization mode. Multiple reaction monitoring (MRM) of m/z 334→263 for NL-1 and m/z 250→179 for NL-2 was done. The method had a linear range of at least 1-100ng/mL in serum. The intra-assay and inter-assay percent coefficient of variation (%CV) were less than 4% and accuracies (%RE) ranged from -2.7% to 2.0%. The analytical procedure gave 96-115% absolute extraction recovery of NL-1. The relative matrix effect was measured and found to be insignificant. The analyte in serum was confirmed to be stable during storage and treatment. The method is suitable for pharmacokinetic (PK) studies of the parent drug NL-1 based on the preliminary serum results from dosed NL-1 mouse studies.

  13. Studying the distribution pattern of selenium in nut proteins with information obtained from SEC-UV-ICP-MS and CE-ICP-MS.

    PubMed

    Kannamkumarath, Sasi S; Wrobel, Katarzyna; Wuilloud, Rodolfo G

    2005-03-31

    In this work, size exclusion chromatography (SEC) with UV and inductively coupled plasma mass spectrometry (ICP-MS) detection was used to study the association of selenium to proteins present in Brazil nuts (Bertholletia excelsa) under five different extraction conditions. As expected, better solubilization of proteins was observed using 0.05molL(-1) sodium hydroxide and 1% sodium dodecylsulfate (SDS) in Tris/HCl buffer (0.05molL(-1), pH 8) as compared to 0.05molL(-1) HCl, 0.05molL(-1) Tris/HCl or hot water (60 degrees C). Due to non-destructive character of Tris-SDS treatment, this was applied for studying molecular weight (MW) distribution patterns of selenium-containing nut proteins. Three different SEC columns were used for obtaining complete MW distribution of selenium: Superdex 75, Superdex Peptide, and Superdex 200 were tested with 50mmolL(-1) Tris buffer (pH 8), 150mmolL(-1) ammonium bicarbonate buffer (pH 7.8), phosphate (pH 7.5), and CAPS (pH 10.0) mobile phases. Using Superdex 200 column, the elution of at least three MW fractions was observed with UV detection (200-10kDa) and ICP-MS chromatogram showed the co-elution of selenium with the two earlier fractions. The apparent MWs of these selenium-containing fractions were respectively about 107 and 50kDa, as evaluated from the column calibration. For further characterization of individual selenium species, the defatted nuts were hydrolyzed with proteinase K and analyzed by capillary electrophoresis (CE) with ICP-MS detection. The suitability of CE for the separation of selenite, selenate, selenocystine and selenomethionine in the presence of the nut sample matrix is demonstrated. Complete separation of the above mentioned selenium species was obtained within a migration time of 7min. In the analysis of nut extracts with CE-ICP-MS, selenium was found to be present mainly as selenomethionine.

  14. A New Social Communication Intervention for Children with Autism: Pilot Randomised Controlled Treatment Study Suggesting Effectiveness

    ERIC Educational Resources Information Center

    Aldred, Catherine; Green, Jonathan; Adams, Catherine

    2004-01-01

    Background: Psychosocial treatments are the mainstay of management of autism in the UK but there is a notable lack of a systematic evidence base for their effectiveness. Randomised controlled trial (RCT) studies in this area have been rare but are essential because of the developmental heterogeneity of the disorder. We aimed to test a new…

  15. An Introductory Course in Indian Studies for Small Colleges: A Suggested Annotated Syllabus.

    ERIC Educational Resources Information Center

    Stern, Robert

    The author outlines an introductory undergraduate course in Indian Studies constructed on the configuration of a social science cluster built around a central disciplinary core of political science. The objective of the course is to build an understanding of contemporary India. As a matter of convenience and organization the course is divided into…

  16. An LC/MS/MS method for stable isotope dilution studies of β-carotene bioavailability, bioconversion, and vitamin A status in humans[S

    PubMed Central

    Oxley, Anthony; Berry, Philip; Taylor, Gordon A.; Cowell, Joseph; Hall, Michael J.; Hesketh, John; Lietz, Georg; Boddy, Alan V.

    2014-01-01

    Isotope dilution is currently the most accurate technique in humans to determine vitamin A status and bioavailability/bioconversion of provitamin A carotenoids such as β-carotene. However, limits of MS detection, coupled with extensive isolation procedures, have hindered investigations of physiologically-relevant doses of stable isotopes in large intervention trials. Here, a sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) analytical method was developed to study the plasma response from coadministered oral doses of 2 mg [13C10]β-carotene and 1 mg [13C10]retinyl acetate in human subjects over a 2 week period. A reverse phase C18 column and binary mobile phase solvent system separated β-carotene, retinol, retinyl acetate, retinyl linoleate, retinyl palmitate/retinyl oleate, and retinyl stearate within a 7 min run time. Selected reaction monitoring of analytes was performed under atmospheric pressure chemical ionization in positive mode at m/z 537→321 and m/z 269→93 for respective [12C]β-carotene and [12C] retinoids; m/z 547→330 and m/z 274→98 for [13C10]β-carotene and [13C5] cleavage products; and m/z 279→100 for metabolites of [13C10]retinyl acetate. A single one-phase solvent extraction, with no saponification or purification steps, left retinyl esters intact for determination of intestinally-derived retinol in chylomicrons versus retinol from the liver bound to retinol binding protein. Coadministration of [13C10]retinyl acetate with [13C10]β-carotene not only acts as a reference dose for inter-individual variations in absorption and chylomicron clearance rates, but also allows for simultaneous determination of an individual's vitamin A status. PMID:24158962

  17. Automated determination of venlafaxine in human plasma by on-line SPE-LC-MS/MS. Application to a bioequivalence study.

    PubMed

    Suenaga, Eunice Mayumi; Ifa, Demian R; Cruz, Alessandro Carvalho; Pereira, Renata; Abib, Eduardo; Tominga, Mineko; Nakaie, Clovis Ryuichi

    2009-02-01

    A new automated SPE-LC-ESI-MS/MS method was developed and validated to quantify venlafaxine in human plasma using fluoxetine as an internal standard. The analytes were automatically extracted from plasma by C18 SPE cartridges, separated on a C8 RP column and analyzed by MS in the multiple reaction-monitoring (MRM) mode. The method has a chromatographic run time of 4.0 min and a linear calibration curve over the range of 0.25-200 ng/mL (r >0.997). The between-run precisions, based on the percent RSD for replicate quality controls (0.75; 80, and 200 ng/mL), were < 8.5% for all concentrations. The between-run accuracies, based on the percent relative error, were < 4.0%. This method was successfully employed in a bioequivalence study of two venlafaxine capsule formulations (test formulation from Eurofarma (Brazil) and Efexor XR, reference formulation, from Wyeth-Whitehall, Brazil) in 48 healthy volunteers of both sexes who received a single 150 mg dose of each formulation. More than 3000 samples were analyzed eliminating the analyst's exposure to hazardous organic solvents normally employed in off-line liquid-liquid extractions. The 90% confidence interval (CI) of the individual ratio geometric mean for Test/Reference was 91.6-103.4% for AUC(0-48 h) and 102.2-112.6% for C(max). Since both 90% CI for AUC(0-48 h) and C(max) were included in the 80-125% interval proposed by the US Food and Drug Administration (FDA) and the Brazilian National Health Surveillance Agency (ANVISA), the test formulation was considered bioequivalent to Efexor XR according to both the rate and extent of absorption.

  18. An LC/MS/MS method for stable isotope dilution studies of β-carotene bioavailability, bioconversion, and vitamin A status in humans.

    PubMed

    Oxley, Anthony; Berry, Philip; Taylor, Gordon A; Cowell, Joseph; Hall, Michael J; Hesketh, John; Lietz, Georg; Boddy, Alan V

    2014-02-01

    Isotope dilution is currently the most accurate technique in humans to determine vitamin A status and bioavailability/bioconversion of provitamin A carotenoids such as β-carotene. However, limits of MS detection, coupled with extensive isolation procedures, have hindered investigations of physiologically-relevant doses of stable isotopes in large intervention trials. Here, a sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) analytical method was developed to study the plasma response from coadministered oral doses of 2 mg [(13)C10]β-carotene and 1 mg [(13)C10]retinyl acetate in human subjects over a 2 week period. A reverse phase C18 column and binary mobile phase solvent system separated β-carotene, retinol, retinyl acetate, retinyl linoleate, retinyl palmitate/retinyl oleate, and retinyl stearate within a 7 min run time. Selected reaction monitoring of analytes was performed under atmospheric pressure chemical ionization in positive mode at m/z 537→321 and m/z 269→93 for respective [(12)C]β-carotene and [(12)C] retinoids; m/z 547→330 and m/z 274→98 for [(13)C10]β-carotene and [(13)C5] cleavage products; and m/z 279→100 for metabolites of [(13)C10]retinyl acetate. A single one-phase solvent extraction, with no saponification or purification steps, left retinyl esters intact for determination of intestinally-derived retinol in chylomicrons versus retinol from the liver bound to retinol binding protein. Coadministration of [(13)C10]retinyl acetate with [(13)C10]β-carotene not only acts as a reference dose for inter-individual variations in absorption and chylomicron clearance rates, but also allows for simultaneous determination of an individual's vitamin A status.

  19. SPE-UPLC-MS/MS method for sensitive and rapid determination of aripiprazole in human plasma to support a bioequivalence study.

    PubMed

    Patel, Daxesh P; Sharma, Primal; Sanyal, Mallika; Shrivastav, Pranav S

    2013-04-15

    An improved and rugged UPLC-MS/MS method has been developed and validated for sensitive and rapid determination of aripiprazole in human plasma using aripiprazole-d8 as the internal standard (IS). The analyte and IS were extracted from 100 μL of human plasma by solid-phase extraction using Phenomenex Strata-X (30 mg, 1 cc) cartridges. Chromatography was achieved on an Acquity UPLC BEH C18 (50 mm × 2.1 mm, 1.7 μm) analytical column using methanol: 10mM ammonium formate (85:15, v/v) as the mobile phase with isocratic elution. Quantitation was done using multiple reaction monitoring in the positive ionization mode. The linearity of the method was established in the concentration range 0.05-80 ng/mL. The mean extraction recovery was greater than 96% across QC levels, while intra- and inter batch accuracy and precision (% CV) values ranged from 97.4 to 101.9% and from 1.20 to 3.72% respectively. The relative matrix effect in eight different lots of plasma samples, expressed as % CV for the calculated slopes of calibration curves was 1.08%. The stability of aripiprazole was studied under different storage conditions. The validated method was used to support a bioequivalence study of 10mg aripiprazole formulation in 36 healthy Indian subjects.

  20. Development of a simple LC-MS/MS method for determination of rebamipide in human plasma and its application to a bioequivalence study.

    PubMed

    Liu, Jian; Shen-Tu, Jianzhong; Wu, Lihua; Dou, Jing; Xu, Qiyang; Zhou, Huili; Wu, Guolan; Hu, Xingjiang

    2012-11-01

    The purpose of this study was to design a simple and rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for a rebamipide bioequivalence study in healthy Chinese male volunteers. In this method, sample pretreatment involved simple protein precipitation with venlafaxine as the internal standard. Analysis was achieved on a ZORBAX SB-C18 column with a concentration range of 6-1200 ng/mL. Rebamipide tablets from Yuanlijian (test, Hangzhou, China) and from Otsuka (reference, Hangzhou, China) were evaluated following a single 300 mg oral dose to 20 healthy volunteers. Bioequivalence was determined by calculating 90% confidence intervals (90% CI) for the ratio of Cmax, AUC(0-t) and AUC(0-infinity) values for the test and reference products, using logarithmic transformed data. The 90% confidence intervals for the ratio of Cmax (83.7-118.4%), AUC(0-t) (91.1-113.4%) and AUC(0-infinity) (90.6-113.2%) values for the test and reference products were within the interval (80.0-125.0% for AUC, and 70-143% for Cmax), proposed by State of Food and Drug Administration [SFDA, 2005. China]. It was concluded that the two rebamipide tablets were bioequivalent in their rate and extent of absorption and the method met the principle of quick and easy clinical analysis.

  1. Development and validation of an LC-MS/MS method for the toxicokinetic study of deoxynivalenol and its acetylated derivatives in chicken and pig plasma.

    PubMed

    Broekaert, N; Devreese, M; De Mil, T; Fraeyman, S; De Baere, S; De Saeger, S; De Backer, P; Croubels, S

    2014-11-15

    This study aims to develop an LC-MS/MS method allowing the determination of 3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, deoxynivalenol and its main in vivo metabolite, deepoxy-deoxynivalenol, in broiler chickens and pigs. These species have a high exposure to these toxins, given their mainly cereal based diet. Several sample cleanup strategies were tested and further optimized by means of fractional factorial designs. A simple and straightforward sample preparation method was developed consisting out of a deproteinisation step with acetonitrile, followed by evaporation of the supernatant and reconstitution in water. The method was single laboratory validated according to European guidelines and found to be applicable for the intended purpose, with a linear response up to 200ngml(-1) and limits of quantification of 0.1-2ngml(-1). As a proof of concept, biological samples from a broiler chicken that received either deoxynivalenol, 3- or 15-acetyl-deoxynivalenol were analyzed. Preliminary results indicate nearly complete hydrolysis of 3-acetyl-deoxynivalenol to deoxynivalenol; and to a lesser extent of 15-acetyl-deoxynivalenol to deoxynivalenol. No deepoxy-deoxynivalenol was detected in any of the plasma samples. The method will be applied to study full toxicokinetic properties of deoxynivalenol, 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol in broiler chickens and pigs.

  2. Study of the degradation of butyltin compounds in surface water samples under different storage conditions using multiple isotope tracers and GC-MS/MS.

    PubMed

    Rodríguez-Cea, Andrés; Rodríguez-González, Pablo; García Alonso, J Ignacio

    2016-03-01

    The degradation of butyltin compounds in surface water samples under different storage conditions has been studied. A triple spike solution, containing monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) labelled with a different tin isotope, was added to the sample to calculate the extent of the interconversion reactions among butyltin compounds. Real surface water samples (river water) were collected and stored in glass, polypropylene or polytetrafluoroethylene (PTFE) containers. The presence of light, addition of acetic acid, storage temperature (22, 4 or -18 °C), and the influence of a filtration step were evaluated. Moreover, Milli-Q water with and without the addition of a high concentration of humic acids was prepared in parallel and the results compared to those obtained from the real samples. The water samples were analysed by gas chromatography-tandem mass spectrometry (GC-MS/MS) in selected reaction monitoring (SRM) mode at two different storage times (2 weeks and 4 months after its preparation) to carry out both a short- and a long-term stability study. The lowest butyltin degradation was obtained when the samples were stored at -18 °C in the dark. Under these conditions, both TBT and DBT showed negligible dealkylation factors after 2 weeks. After 4 months, DBT dealkylation to MBT increased up to 19 % but TBT degradation was not observed.

  3. Validated LC-MS/MS method for simultaneous quantification of resveratrol levels in mouse plasma and brain and its application to pharmacokinetic and brain distribution studies.

    PubMed

    Ramalingam, Prakash; Ko, Young Tag

    2016-02-05

    A rapid, selective, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine resveratrol levels in plasma and brain tissue in mice for supporting pharmacokinetic and brain distribution studies. Analytes were separated using a Sepax BR-C18 analytical column (5μm, 120Å, 1.0×100mm) and eluted using an isocratic elution mobile phase acetonitrile and 0.01% formic acid [60:40, v/v] at a flow rate of 0.1mL/min. Precursor and product ion transitions for analyte resveratrol m/z 226.9>184.8 and curcumin m/z 367.1>148.9 were monitored using triple quadrupole mass spectrometer with multiple reaction monitoring (MRM) in negative ionization mode. The method was validated with respect to accuracy, within- and between-day precision, linearity, limit of quantification, recovery, and matrix effects of analyte. The inter- and intra-day accuracy and precision were within the range of the US Food and Drug Administration (FDA) acceptance criteria, for both matrices. The method was also successfully applied to pharmacokinetic and brain distribution studies of resveratrol after intravenous administration of free resveratrol and resveratrol-loaded solid lipid nanoparticles to mice. The combined use of serial blood sampling, small sample volume, simple extraction, and capillary depletion method drastically improved resveratrol analysis from biological matrices.

  4. Quantitative bioanalysis of antibody-conjugated payload in monkey plasma using a hybrid immuno-capture LC-MS/MS approach: Assay development, validation, and a case study.

    PubMed

    Liu, Ang; Kozhich, Alexander; Passmore, David; Gu, Huidong; Wong, Richard; Zambito, Frank; Rangan, Vangipuram S; Myler, Heather; Aubry, Anne-Françoise; Arnold, Mark E; Wang, Jian

    2015-10-01

    Antibody drug conjugates (ADCs) are complex molecules composed of two pharmacologically distinct components, the cytotoxic payload and the antibody. The measurement of the payload molecules that are attached to the antibody in vivo is important for the evaluation of the safety and efficacy of ADCs, and can also provide distinct information compared to the antibody-related analytes. However, analyzing the antibody-conjugated payload is challenging and in some cases may not be feasible. The in vivo change in drug antibody ratio (DAR), due to deconjugation, biotransformation or other clearance phenomena, generates unique and additional challenges for ADC analysis in biological samples. Here, we report a novel hybrid approach with immuno-capture of the ADC, payload cleavage by specific enzyme, and LC-MS/MS of the cleaved payload to quantitatively measure the concentration of payload molecules still attached to the antibody via linker in plasma. The ADC reference material used for the calibration curve is not likely to be identical to the ADC measured in study samples due to the change in DAR distribution over the PK time course. The assay clearly demonstrated that there was no bias in the measurement of antibody-conjugated payload for ADC with varying DAR, which thus allowed accurate quantification even when the DAR distribution dynamically changes in vivo. This hybrid assay was fully validated based on a combination of requirements for both chromatographic and ligand binding methods, and was successfully applied to support a GLP safety study in monkeys.

  5. Simultaneous determination and pharmacokinetic study of four phenolic acids in rat plasma using UFLC-MS/MS after intravenous administration of salvianolic acid for injection.

    PubMed

    Xie, Xiuman; Miao, Jingzhuo; Sun, Wanyang; Huang, Jingyi; Li, Dongxiang; Li, Shuming; Tong, Ling; Sun, Guoxiang

    2017-02-05

    A simple, sensitive and selective ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was established for simultaneous determination and pharmacokinetic study of rosmarinic acid (RA), salvianolic acid D (Sal D), lithospermic acid (LA) and salvianolic acid B (Sal B) in rat plasma after intravenous administration of salvianolic acid for injection (SAFI). Three doses of administration, containing 14, 28 and 56mg/kg, were investigated in this study. Plasma samples were pretreated using protein precipitation (PP) with pre-cooled acetonitrile. Chromatographic separation was achieved on a CORTECS™ UPLC C18 column (1.6μm, 2.1×100mm) with a mobile phase composed of 0.1% formic acid aqueous (V/V) and 0.1% formic acid acetonitrile (V/V). Analytes were detected using electrospray ionization (ESI) source in negative ionization mode and quantified in multiple reaction monitoring (MRM) mode. The validated method is stable and reliable. No significant difference of half lives (t1/2) of four analytes at three doses was observed. Area under the curve (AUC0-∞) and peak concentration (Cmax) of the four analytes demonstrated a linear increase in across the doses with the linear correlation r of each analyte at three doses were greater than 0.95. It indicated that the pharmacokinetic behavior of SAFI is positively related to dose at the range of 14-56mg/kg.

  6. Forced degradation, LC-UV, MS(n) and LC-MS-TOF studies on azilsartan: Identification of a known and three new degradation impurities.

    PubMed

    Kaushik, Dhiraj; Kaur, Jasmeen; Paul Kaur, Vaneet; Saini, Balraj; Bansal, Yogita; Bansal, Gulshan

    2016-02-20

    In the present study, Azilsartan (AZL) was subjected to ICH recommended forced degradation conditions of hydrolysis, oxidation, dry heat and photolysis. The drug degraded to four degradation products (I-IV) under acidic, alkaline and water hydrolysis and photolysis. All the four degradation products were resolved in a single run on a C-18 column (250mm×4.6mm; 5μ) with isocratic elution using mobile phase composed of ammonium formate (20mM, pH 3.0), methanol and acetonitrile (40:5:40% v/v), at a flow rate of 0.8mlmin(-1) at ambient temperature. The products were characterized through +ESI-MS(n) spectra of AZL and LC-MS-TOF studies as 2-ethoxy-3H-benzo-imidazole-4-carboxylic acid (I), 2-hydroxy-3-[2'-(5-oxo-4,5-dihydro-[1,2,4]oxadiazol-4-ylmethyl]-3H-benzoimidazole-4-carboxylic acid (II, deethylated AZL), 3-[2'-(1H-diazirin-3-yl)-biphenyl]-4-ylmethyl]-2-ethoxy-3H-benzoimidazole-4-carboxylic acid (III), and 3-[4'-(2-ethoxy-benzo-imidazol-1-ylmethyl)-biphenyl-2-yl]-4H-[1,2,4]oxadiazol-5-one (IV, decarboxylated AZL). Product I was found to be a known process related impurity whereas the products II-IV were identified as new degradation impurities. The most probable mechanisms for formation of these degradation products were proposed.

  7. LC-ESI-MS/MS method for bioanalytical determination of osteogenic phytoalexin, medicarpin, and its application to preliminary pharmacokinetic studies in rats.

    PubMed

    Taneja, Isha; Raju, Kanumuri Siva Rama; Challagundla, Muralikrishna; Raghuvanshi, Ashutosh; Goel, Atul; Wahajuddin, Muhammad

    2015-09-15

    Medicarpin is the active phytoalexin found in the stem bark of Butea monosperma having potent osteogenic activity. An LC-ESI-MS/MS was developed and validated for quantification of medicarpin in rat plasma using liquid-liquid extraction technique and diethyl ether as the extraction solvent. Medicarpin was separated on RP18 column (4.6mm×50mm, 5.0μm) using methanol and 10mM ammonium acetate (pH 4.0) in the ratio of 80:20 (v/v) as mobile phase. The method was linear within the concentration range of 1-500ng/mL and its sensitivity was 1ng/mL. The precision value for intra- and inter-day assays and stability assays was within 0.88-14.22% while the accuracy ranged between 87.46-116.0% at all four QC levels. The validated method was successfully applied to study the preclinical pharmacokinetics of medicarpin in rats. Medicarpin showed multiple peak phenomenon upon oral administration. Its oral bioavailability was 17.43%. It was found to be a rapidly absorbed (Tmax=15min), 81.61% protein bound and pH stable compound. The present study provides important information regarding preliminary pharmacokinetics of medicarpin for its further exploration as a potential therapeutic agent.

  8. An LC-MS/MS method for the determination of digitoxigenin in skin samples and its application to skin permeation and metabolic stability studies.

    PubMed

    Feng, Xinchi; Turley, Joel; Xie, Zijian; Pierre, Sandrine V; Koc, Hasan; Khan, M Omar; Hao, Jinsong

    2017-05-10

    An LC-MS/MS method was developed for the determination of digitoxigenin in mice skin samples. Chromatographic separation was achieved on an Agilent Poroshell 120 EC-C18 column. Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an ESI interface operating in a positive ionization mode. Quantification was performed using selective reaction monitoring of the precursor-product ion transitions of m/z 375.5→339 for digitoxigenin and m/z 391.5→337 for internal standard (IS). The calibration curves were linear over the concentration range of 1.00-500ng/mL. The intra- and inter-batch precision was no more than 10.6% of the coefficient of variation and the accuracy was within ±8.1% of the actual values. This validated method has been successfully applied to skin permeation and skin metabolic stability studies of digitoxigenin in mice. The steady-state flux and lag time of digitoxigenin permeated across the full-thickness mice skin were 1.86±0.45μg/cm(2)/h and 0.46±0.18h, respectively. The metabolism of digitoxigenin in the skin was not detected in our study.

  9. A rapid and sensitive UHPLC-MS/MS assay for the determination of trelagliptin in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Hu, Xiao-Xia; Lan, Tian; Chen, Zhe; Yang, Cheng-Cheng; Tang, Peng-Fei; Yuan, Ling-Jing; Hu, Guo-Xin; Cai, Jian-Ping

    2016-10-15

    This study aims to develop and validate a simple, rapid and sensitive ultra-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method for exploring pharmacokinetic characteristics of trelagliptin. Protein precipitation by acetonitrile was used to prepare plasma sample. A RRHD Eclipse Plus C18 (2.1×50mm, 1.8μ) column with gradient mobile phase (containing acetonitrile and 0.1% formic acid) help to achieve the separation of trelagliptin and carbamazepine (IS) with high selectivity. Detection of target fragment ions m/z 358.2→133.9 for trelagliptin, and m/z 237.1→194.0 for IS was performed in positive-ion electrospray ionization mass spectrometry by multiple reaction monitoring. Linear calibration plots were achieved in the range of 5-4000ng/mL for trelagliptin (R(2)=0.999) in rat plasma. The recovery of trelagliptin ranged from 87.8% to 93.7%. The method was showed to be accurate, precise and stable. No obvious matrix effect was found. It has been fully validated and successfully applied to pharmacokinetic study of trelagliptin.

  10. LC-MS/MS determination and urinary excretion study of seven alkaloids in healthy Chinese volunteers after oral administration of Shuanghua Baihe tablets.

    PubMed

    Cheng, Minlu; Liu, Ruijuan; Wu, Yao; Gu, Pan; Zheng, Lu; Liu, Yujie; Ma, Pengcheng; Ding, Li

    2016-01-25

    An LC-MS/MS method was developed and validated for the simultaneous determination of magnoflorine, berberrubine, jatrorrhizine, coptisine, epiberberine, palmatine and berberine in human urine. The sample preparation procedure involved the four-fold dilution of the urine samples with acetonitrile/water (1:3, v/v). The chromatographic separation was achieved on a Hedera ODS-2 column under gradient elution at a flow rate of 0.4 mL/min with acetonitrile and water containing 0.5% formic acid as the mobile phase. The mass detection was performed in the positive mode. Calibration curves of the seven alkaloids showed good linearity (correlation coefficients>0.9973) over their concentration ranges. To meet the requirements of urinary excretion study for each alkaloid in human, the lower limit of quantification was set at different values from 0.05063 ng/mL to 2.034 ng/mL for the seven alkaloids, respectively. The intra- and inter-batch precision and accuracy were all within ± 15%. No matrix effect was observed for the analytes. The validated method was applied to the excretion study for the seven alkaloids in healthy Chinese volunteers after oral administration of Shuanghua Baihe tablets. The average 72 h cumulative urinary excretion of magnoflorine, berberrubine, jatrorrhizine, coptisine, epiberberine, palmatine and berberine accounted for 1.81%, 0.27%, 0.29%, 0.046%, 0.027%, 0.010% and 0.021% of the respective administered dose.

  11. Simultaneous determination of eight bioactive components of Qishen Yiqi Dripping Pills in rat plasma using UFLC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Shao, Yaping; Zhang, Wen; Tong, Ling; Huang, Jingyi; Li, Dongxiang; Nie, Wei; Zhu, Yan; Li, Yunfei; Lu, Tao

    2017-02-01

    In this study, a rapid and reliable ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed and validated for the simultaneous determination of eight active ingredients, including astragaloside IV (AIV), ononin (ONO), tanshinol (TSL), protocatechualdehyde (PCA), protocatechuic acid (PA), salvianolic acid D (SAD), rosmarinic acid (RA), and ginsenoside Rg1 (GRg1 ), in rat plasma. The plasma samples were pretreated by protein precipitation with acetonitrile. Chromatographic separation was performed on a Waters Acquity UPLC® BEH C18 column (1.7 µm particles, 2.1 × 100 mm).The mobile phase consisted of 0.1% aqueous formic acid (A)-acetonitrile with 0.1% formic acid (B) at a flow rate of 0.4 mL/min. Quantification was performed on a triple quadruple tandem mass spectrometry with electrospray ionization by multiple reaction monitoring both in the negative and positive ion mode. The lower limit of quantification (LLOQ) of TSL was 2.0 ng/mL and the others were 5.0 ng/mL. The extraction recoveries, matrix effects, intra- and inter-day precision and accuracy of eight tested components were all within acceptable limits. The validated method was successfully applied to the pharmacokinetic study of the eight active constituents after intragastric administration of three doses (1.0, 3.0, 6.0 g/kg body weight) of Qishen Yiqi dripping pills to rats.

  12. Study on degradation kinetics of 2-(2-hydroxypropanamido) benzoic acid in aqueous solutions and identification of its major degradation product by UHPLC/TOF-MS/MS.

    PubMed

    Zhang, Qili; Guan, Jiao; Rong, Rong; Zhao, Yunli; Yu, Zhiguo

    2015-08-10

    A RP-HPLC method was developed and validated for the degradation kinetic study of 2-(2-hydroxypropanamido) benzoic acid (HPABA), a promising anti-inflammatory drug, which would provide a basis for further studies on HPABA. The effects of pH, temperature, buffer concentration and ionic strength on the degradation kinetics of HPABA were discussed. Experimental parameters such as degradation rate constants (k), activation energy (Ea), acid and alkali catalytic constants (k(ac), k(al)), shelf life (t1/2) and temperature coefficient (Q10) were calculated. The results indicated that degradation kinetics of HPABA followed zero-order reaction kinetics; degradation rate constants (k) of HPABA at different pH values demonstrated that HPABA was more stable in neutral and near-neutral conditions; the function of temperature on k obeyed the Arrhenius equation (r = 0.9933) and HPABA was more stable at lower temperature; with the increase of ionic strength and buffer concentration, the stability of HPABA was decreased. The major unknown degradation product of HPABA was identified by UHPLC/TOF-MS/MS with positive electrospray ionization. Results demonstrated that the hydrolysis product was the primary degradation product of HPABA and it was deduced as anthranilic acid.

  13. UHPLC-MS/MS determination and pharmacokinetic study of plantamajoside in rat plasma after oral administration of single plantamajoside and Plantago asiatica extract.

    PubMed

    Bai, Lizhi; Han, Li; Lu, Xiaoguang; Kang, Xin; Fan, Zhiwei; Xing, Rong; Zhou, Dangxia

    2017-05-01

    A sensitive and reliable ultra-high performance liquid chromatography coupled with tandem quadrupole mass spectrometry (UHPLC-MS/MS) method was developed for quantitation of plantamajoside in rat plasma. First, this study compared the pharmacokinetic properties of plantamajoside after oral administration of Plantago asiatica extract and pure plantamajoside in rat plasma with approximately the same dosage of 8.98 mg/kg. Second, chromatographic separation was performed on an Acquity HSS C18 column (50 × 2.1 mm, p.d.1.7 μm) with isocratic elution using methanol-water (80:20, v/v) as mobile phase at a flow rate of 0.25 mL/min. The calibration curves were linear over the range of 0.1-100 ng/mL for plantamajoside. At different time points (0, 0.083, 0.167, 0.25, 0.5, 0.75, 1, 2, 3, 4, 5, 6 and 8 h) after administration, the concentrations of plantamajoside in plasma were measured and the main pharmacokinetic parameters were estimated. The study indicates that the pharmacokinetics of plantamajoside in rat plasma have significant differences between two groups.

  14. THC:CBD spray and MS spasticity symptoms: data from latest studies.

    PubMed

    Rekand, Tiina

    2014-01-01

    New clinical experience with 9-delta-tetrahydocannabinol (THC) and cannabidiol (CBD) oromucosal spray (Sativex®) involving more than an additional 1,000 patients with MS spasticity (approximately 150 in clinical studies and 900 in post-marketing surveillance studies) have become available in 2013 and are reviewed. A randomized, placebo controlled long-term follow-up clinical trial with THC:CBD spray versus placebo demonstrated that it was not associated with cognitive decline, depression or significant mood changes after 12 months of treatment. Furthermore, in a prospective observational pilot study involving 33 patients (60% female) aged 33-68 years and a mean disease duration of 6.6 years, THC:CBD oromucosal spray did not adversely influence standard driving ability in patients with moderate to severe MS spasticity. Other new long term observational data about the use of THC:CBD oromucosal spray in clinical practice are available from patient registries in the UK, Germany and Spain. Findings to date reinforce the efficacy and safety observed in Phase III clinical trials. It is of interest that in practice average dosages used by patients tended to be lower than those reported in clinical studies (5-6.4 vs. >8 sprays/day), and effectiveness was maintained in the majority of patients. Importantly, no additional safety concerns were identified in the registry studies which included findings from patients who have been treated for prolonged periods (in the German/UK registry 45% of patients had >2 years exposure). Thus, these new data support a positive benefit-risk relationship for THC:CBD oromucosal spray during longer-term use.

  15. LC-MS/MS bioanalysis of loratadine (Claritin) in dried blood spot (DBS) samples collected by subjects in a clinical research study.

    PubMed

    Li, Wenkui; Doherty, John; Moench, Paul; Flarakos, Jimmy; Tse, Francis L S

    2015-03-01

    A high-performance liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has been developed and validated for the quantitative analysis of loratadine, an H1 histamine antagonist, in human dried blood spot (DBS) samples following a single self-administered 10 or 20mg oral dose. The samples were produced by spotting approximately 30μl of whole blood onto PE-226 cards. Two 3-mm discs were cut from the DBS samples and extracted using aqueous methanol containing the internal standard. After transfer and drying of the resulting sample extract, the reconstituted residues were chromatographed using a Waters XSelect C18 column and isocratic elution for MS/MS detection. The possible impact due to hematocrit, volume of blood sample spotted, storage temperature, and humidity, on the accuracy of measured DBS results were investigated. The results showed that only spotted blood volume might have an impact; a small volume (10μl) tended to give a larger negative bias in the measured value than the large volume ones (≥20μl). The current method was fully validated over a dynamic range of 0.200-20.0ng/ml with correlation coefficients (r(2)) for three validation batches equal to or better than 0.990. The intra-day accuracy and precision at the LLOQ were -11.5 to 0.0% bias and 6.4 to 8.9% CV, respectively. For the other QC samples (0.600, 3.00, 10.0 and 15.0ng/ml), the precision ranged from 4.2 to 9.8% CV and from 6.3 to 8.1% CV, respectively, in the intra-day and inter-day evaluations; the accuracy ranged from -1.7 to 10.0% and 2.7 to 5.3% bias, respectively, in the intra-day and inter-day batches. Loratadine is stable in the DBS samples for at least 271 days at ambient temperature in a desiccator, for at least 24h at 60°C and under 80% relative humidity, followed by re-conditioning at ambient temperature in a desiccator. The current methodology has been applied to determine the loratadine levels in DBS samples collected by subjects in a clinical research study to

  16. Stereoselective determination of ginsenosides Rg3 and Rh2 epimers in rat plasma by LC-MS/MS: application to a pharmacokinetic study.

    PubMed

    Bae, Soo Hyeon; Zheng, Yu Fen; Yoo, Young Hyo; Kim, Jeom Yong; Kim, Sun Ok; Jang, Min Jung; Seo, Jae Hong; Bae, Soo Kyung

    2013-06-01

    We developed and validated an accurate and sensitive LC-MS/MS method for the simultaneous quantitation of ginsenoside Rg3 and Rh2 epimers (R-Rg3, S-Rg3, R-Rh2, and S-Rh2) in rat plasma. Analytes were extracted from 0.1 mL aliquots of rat plasma by liquid-liquid extraction, using 2 mL of ethyl acetate. In this assay, dioscin (500 ng/mL) was used as an internal standard. Chromatographic separation was conducted using an Acclaim RSLC C18 column (150 × 2.1 mm, 2.2 μm) at 40°C, with a gradient mobile phase consisting of 0.1% formic acid in distilled water and in acetonitrile, a flow rate of 0.35 mL/min, and a total run time of 20 min. Detection and quantification were performed using a mass spectrometer in selected reaction-monitoring mode with negative electrospray ionization at m/z 783.4 → 161.1 for R-Rg3 and S-Rg3, m/z 621.3 → 161.1 for R-Rh2 and S-Rh2, and m/z 867.2 → 761.5 for the internal standard. For R-Rg3 and S-Rg3, the lower limit of quantification was 5 ng/mL, with a linear range up to 500 ng/mL; for R-Rh2 and S-Rh2, the lower limit of quantification was 150 ng/mL, with a linear range up to 6000 ng/mL. The coefficient of variation for assay precision was less than 10.5%, with an accuracy of 86.4-112%. No relevant cross-talk or matrix effect was observed. The method was successfully applied to a pharmacokinetic study after oral administration of 400 mg/kg and 2000 mg/kg of BST204, a fermented ginseng extract, to rats. We found that the S epimers exhibited significantly higher plasma concentrations and area under curve values for both Rg3 and Rh2. This is the first report on the separation and simultaneous quantification of R-Rg3, S-Rg3, R-Rh2, and S-Rh2 in rat plasma by LC-MS/MS. The method should be useful in the clinical use of ginseng or its derivatives.

  17. Eye Movement Training and Suggested Gaze Strategies in Tunnel Vision - A Randomized and Controlled Pilot Study

    PubMed Central

    Ivanov, Iliya V.; Mackeben, Manfred; Vollmer, Annika; Martus, Peter; Nguyen, Nhung X.; Trauzettel-Klosinski, Susanne

    2016-01-01

    Purpose Degenerative retinal diseases, especially retinitis pigmentosa (RP), lead to severe peripheral visual field loss (tunnel vision), which impairs mobility. The lack of peripheral information leads to fewer horizontal eye movements and, thus, diminished scanning in RP patients in a natural environment walking task. This randomized controlled study aimed to improve mobility and the dynamic visual field by applying a compensatory Exploratory Saccadic Training (EST). Methods Oculomotor responses during walking and avoiding obstacles in a controlled environment were studied before and after saccade or reading training in 25 RP patients. Eye movements were recorded using a mobile infrared eye tracker (Tobii glasses) that measured a range of spatial and temporal variables. Patients were randomly assigned to two training conditions: Saccade (experimental) and reading (control) training. All subjects who first performed reading training underwent experimental training later (waiting list control group). To assess the effect of training on subjects, we measured performance in the training task and the following outcome variables related to daily life: Response Time (RT) during exploratory saccade training, Percent Preferred Walking Speed (PPWS), the number of collisions with obstacles, eye position variability, fixation duration, and the total number of fixations including the ones in the subjects' blind area of the visual field. Results In the saccade training group, RTs on average decreased, while the PPWS significantly increased. The improvement persisted, as tested 6 weeks after the end of the training. On average, the eye movement range of RP patients before and after training was similar to that of healthy observers. In both, the experimental and reading training groups, we found many fixations outside the subjects' seeing visual field before and after training. The average fixation duration was significantly shorter after the training, but only in the

  18. Sensitivity of GC-EI/MS, GC-EI/MS/MS, LC-ESI/MS/MS, LC-Ag(+) CIS/MS/MS, and GC-ESI/MS/MS for analysis of anabolic steroids in doping control.

    PubMed

    Cha, Eunju; Kim, Sohee; Kim, Ho Jun; Lee, Kang Mi; Kim, Ki Hun; Kwon, Oh-Seung; Lee, Jaeick

    2015-01-01

    This study compared the sensitivity of various separation and ionization methods, including gas chromatography with an electron ionization source (GC-EI), liquid chromatography with an electrospray ionization source (LC-ESI), and liquid chromatography with a silver ion coordination ion spray source (LC-Ag(+) CIS), coupled to a mass spectrometer (MS) for steroid analysis. Chromatographic conditions, mass spectrometric transitions, and ion source parameters were optimized. The majority of steroids in GC-EI/MS/MS and LC-Ag(+) CIS/MS/MS analysis showed higher sensitivities than those obtained with other analytical methods. The limits of detection (LODs) of 65 steroids by GC-EI/MS/MS, 68 steroids by LC-Ag(+) CIS/MS/MS, 56 steroids by GC-EI/MS, 54 steroids by LC-ESI/MS/MS, and 27 steroids by GC-ESI/MS/MS were below cut-off value of 2.0 ng/mL. LODs of steroids that formed protonated ions in LC-ESI/MS/MS analysis were all lower than the cut-off value. Several steroids such as unconjugated C3-hydroxyl with C17-hydroxyl structure showed higher sensitivities in GC-EI/MS/MS analysis relative to those obtained using the LC-based methods. The steroids containing 4, 9, 11-triene structures showed relatively poor sensitivities in GC-EI/MS and GC-ESI/MS/MS analysis. The results of this study provide information that may be useful for selecting suitable analytical methods for confirmatory analysis of steroids.

  19. Water on Mars: A status report and suggestions for further study

    NASA Astrophysics Data System (ADS)

    Rummel, John; McKay, Christopher P.

    2016-07-01

    The most recent MEPAG review of Mars Special Regions (Rummel et al., 2014) contained the following statement, "Mars' average atmospheric pressure allows for liquid water when it exceeds that of the triple point of water, and at lower altitudes (e.g., Hellas and Argyre Basins) that is commonly the case. Higher temperatures and/or insolation may allow melting or condensation over limited areas for short time periods." Nonetheless, the US National Academies - European Science Foundation review of the MEPAG report disagreed with a preliminary statement regarding the potential for snow fallen on Mars to melt, and thus stated that, "The review committee asserts that pure liquid water simply cannot exist on Mars because the atmosphere is too dry to allow it. The partial pressure of atmospheric water vapor is typically less than 1 Pa near the surface of Mars, whereas the partial pressure of water vapor at the triple point of water is about 600 Pa." This paper will address the discrepancies between what the MEPAG paper actually asserted, and the validity of the arguments in each report and in the literature for and against liquid water on Mars - whether salty or pure (as the Mars-driven snow). Refs: Committee to Review the MEPAG Report on Mars Special Regions; Space Studies Board; The [US] National Academies of Sciences, Engineering, and Medicine; European Space Sciences Committee; European Science Foundation. (2015). Review of the MEPAG Report on Mars Special Regions. National Academy Press, Washington, DC. Rummel, J. D., Beaty, D. W., Jones, M. A., Bakermans, C., Barlow, N. G., Boston, P. J., ... & Wray, J. J. (2014). A New Analysis of Mars "Special Regions": Findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG2). Astrobiology, 14, 887-968.

  20. Highly Sensitive LC-MS-MS Method for the Determination of Tacrine in Rat Plasma: Application to Pharmacokinetic Studies in Rats.

    PubMed

    Ponnayyan Sulochana, Suresh; Ravichandiran, Vishnuvardh; Mullangi, Ramesh; Sukumaran, Sathesh Kumar

    2016-03-01

    A rapid and highly sensitive assay method has been developed and validated for the estimation of tacrine in rat plasma using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. The assay procedure involves a simple liquid-liquid extraction of tacrine and phenacetin (internal standard, IS) from rat plasma using ethyl acetate. Chromatographic separation was achieved with 0.2% formic acid : acetonitrile (30 : 70, v/v) at a flow rate of 0.50 mL/min on an Atlantis dC18 column with a total run time of 3.0 min. The MS-MS ion transitions monitored were 199.10 → 171.20 for tacrine and 180.10 → 110.10 for IS. Method validation was performed as per United States Food and Drug Administration (US FDA) guidelines and the results met the acceptance criteria. The lower limit of quantification achieved was 0.008 ng/mL and linearity was observed from 0.008 to 53.4 ng/mL. The intra- and inter-day precision was in the range of 2.76-12.5 and 5.15-12.8%, respectively. This novel method has been applied to a pharmacokinetic study in rats.

  1. Simultaneous determination of catechin, epicatechin and epicatechin gallate in rat plasma by LC-ESI-MS/MS for pharmacokinetic studies after oral administration of Cynomorium songaricum extract.

    PubMed

    Zhang, Qiu-Hong; Wang, Wen-Biao; Li, Jin; Chang, Yan-Xu; Wang, Yue-Fei; Zhang, Jishu; Zhang, Bo-Li; Gao, Xiu-Mei

    2012-01-01

    A rapid and valid method was developed for simultaneous determination catechin, epicatechin and epicatechin gallate in rat plasmas using scopoletin (103 ng mL(-1)) as an internal standard (IS). The separation was performed on Eclipse plus C18 column (100 mm × 4.6 mm, 1.8 μm) at a flow rate of 0.3 mL min(-1), and acetonitrile-0.1% formic acid was used as mobile phase. The recoveries of three analytes and IS were more than 78.9%. The lower limits of quantitation (LLOQ) in rat plasma were 2.14, 2.38 and 2.08 ng mL(-1) respectively for catechin, epicatechin and epicatechin gallate. Intra-day and inter-day precisions were within 12%. The accuracies were more than 85%. After single oral administration of 15.25 g kg(-1) Cynomorium songaricum extract, C(max) of catechin, epicatechin and epicatechin gallate in rat plasma were respectively 86.69±38.65, 32.57±15.00 and 36.93±12.62 ng mL(-1) while T(max) values were respectively 0.15±0.09, 0.20±0.10 and 0.20±0.13 h. The results demonstrated that the present LC-MS/MS method was sensitive enough for pharmacokinetic study of catichins following oral administration of C. songaricum extract.

  2. Studies into the phenolic patterns of different tissues of pineapple (Ananas comosus [L.] Merr.) infructescence by HPLC-DAD-ESI-MS (n) and GC-MS analysis.

    PubMed

    Steingass, Christof B; Glock, Mona P; Schweiggert, Ralf M; Carle, Reinhold

    2015-08-01

    In a comprehensive study, more than 60 phenolic compounds were detected in methanolic extracts from different tissues of pineapple infructescence by high-performance liquid chromatography with diode array detection and electrospray ionisation multiple-stage mass spectrometry (HPLC-DAD-ESI-MS (n) ) as well as by gas chromatography-mass spectrometry (GC-MS). The analytical workflow combining both methods revealed numerous compounds assigned for the first time as pineapple constituents by their mass fragmentations. Pineapple crown tissue was characterised by depsides of p-coumaric and ferulic acid. In contrast, major phenolic compounds in pineapple pulp extracts were assigned to diverse S-p-coumaryl, S-coniferyl and S-sinapyl derivatives of glutathione, N-L-γ-glutamyl-L-cysteine and L-cysteine, which were also identified in the peel. The latter was additionally characterised by elevated concentrations of p-coumaric, ferulic and caffeic acid depsides and glycerides, respectively. Two peel-specific cyanidin hexosides were found. Elevated concentrations of isomeric N,N'-diferuloylspermidines may be a useful tool for the detection of fraudulent peel usage for pineapple juice production. Mass fragmentation pathways of characteristic pineapple constituents are proposed, and their putative biological functions are discussed.

  3. A validated LC-MS/MS method for quantitative analysis of curcumin in mouse plasma and brain tissue and its application in pharmacokinetic and brain distribution studies.

    PubMed

    Ramalingam, Prakash; Ko, Young Tag

    2014-10-15

    Curcumin is a well-known multitherapeutic agent widely employed in neurodegenerative disorders and cancer. A selective, fast, and sensitive method employing liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated for the simultaneous determination of curcumin in mouse plasma and brain tissue, by using salbutamol as an internal standard. Triple quadrupole mass detection with multiple reaction monitoring (MRM) mode was used to monitor the ion transitions, m/z of 369>285 for curcumin, and m/z of 240>148 for salbutamol. The method was validated for recovery, accuracy, precision, linearity, and applicability. The lower limits of quantification (LLOQ) in both matrices were 2.5ng/mL. The inter-day and intra-day precisions and accuracy values were within the Food and Drug Administration (FDA) acceptance criteria, for both matrixes. The method was successfully applied in pharmacokinetics and brain distribution studies of curcumin after intravenous administration of free curcumin and curcumin-loaded solid lipid nanoparticles to mice. Furthermore, the application of this method along with serial blood sampling in mice has led to significant reduction in animal use and dosage and drastic improvement in speed, throughput, and quality of pharmacokinetic parameters.

  4. A rapid and sensitive LC-MS/MS method for determination of lercanidipine in human plasma and its application in a bioequivalence study in Chinese healthy volunteers.

    PubMed

    Li, Xiaobing; Shi, Fuguo; He, Xiaojing; Jian, Lingyan; Ding, Li

    2016-09-05

    A rapid and highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of lercanidipine (LER) in human plasma. The plasma sample was deproteinized with methanol after addition of diazepam (internal standard, IS) and separated on a 38°C Hedera ODS-2 analytical column with a mobile phase of methanol and 5mM ammonium acetate buffer solution containing 0.1% formic acid at an isocratic flow rate of 400μL/min. The detection was performed on an API 4000 tandem mass spectrometer coupled with electrospray ionization (ESI) source in positive ESI mode. Quantification was conducted by multiple reaction monitoring (MRM) of the transitions of m/z 612.2→280.2 for LER and m/z 285.1→193.1 for IS, respectively. The method exhibited high sensitivity (LLOQ of 0.015ng/mL) and good linearity over the concentration range of 0.015-8.0ng/mL. No matrix effect and carry-over effect were observed. The values on both the occasions (intra- and inter-day) were all within 15% at three concentration levels. This robust method was successfully applied in a bioequivalence study to evaluate the pharmacokinetics of LER in 59 healthy male Chinese volunteers after a single oral administration of 10mg LER.

  5. Development and Validation of a LC-MS/MS Method for the Simultaneous Estimation of Amlodipine and Valsartan in Human Plasma: Application to a Bioequivalence Study.

    PubMed

    Jangala, Hemanth; Vats, Poonam; Khuroo, Arshad Hussain; Monif, Tausif

    2014-01-01

    A reliable, simple, and robust liquid chromatography-tandem mass spectro-metric (LC-MS/MS) method has been developed and validated that employs solid-phase extraction for the simultaneous estimation of amlodipine and valsartan in human K3EDTA plasma using amlodipine-d4 and valsartan-d9 as internal standards. Chromatographic separation of amlodipine and valsartan was achieved on the Luna C18 (2)100A (150 × 4.6 mm, 5 μm) column using acetonitrile: 5 mM ammonium formate solution (80:20, v/v) as the mobile phase at a flow rate of 0.8 mL/min in isocratic mode. Quantification was achieved using an electrospray ion interface operating in positive mode, under multiple reaction monitoring (MRM) conditions. The assay was found to be linear over the range of 0.302-20.725 ng/mL for amlodipine and 6.062-18060.792 ng/mL for valsartan. The method has shown good reproducibility, as intra- and interday precisions were within 10% and accuracies were within 8% of nominal values for both analytes. The method was successfully applied for the bioequivalence study of amlodipine and valsartan after oral administration of a fixed dose of the combination. Additionally, as required by the current regulatory bodies, incurred sample reanalysis was performed and found to be acceptable.

  6. Simultaneous quantification of methylene blue and its major metabolite, azure B, in plasma by LC-MS/MS and its application for a pharmacokinetic study.

    PubMed

    Kim, Soo-Jin; Ha, Dong-Jin; Koo, Tae-Sung

    2014-04-01

    A simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of methylene blue (MB) and its major metabolite, azure B (AZB), in rat plasma. A simple protein precipitation using acetonitrile was followed by injection of the supernatant on to a Zorbax HILIC Plus column (3.5 µm, 2.1 × 100 mm) with isocratic mobile phase consisting of 5 mM ammonium acetate in 10:90 (v/v) water:methanol at a flow rate of 0.3 mL/min and detection in positive ionization mode. The standard curve was linear over the concentration range from 1 to 1000 ng/mL for MB and AZB with coefficient of determination above 0.9930. The lower limit of quantification was 1 ng/mL using 20 μL of rat plasma sample. The intra- and inter-assay precision and accuracy were <12%. The developed analytical method was successfully applied to the pharmacokinetic study of MB and AZB in rats.

  7. Development and Validation of a LC-MS/MS Method for the Simultaneous Estimation of Amlodipine and Valsartan in Human Plasma: Application to a Bioequivalence Study

    PubMed Central

    Jangala, Hemanth; Vats, Poonam; Khuroo, Arshad Hussain; Monif, Tausif

    2014-01-01

    Abstract A reliable, simple, and robust liquid chromatography-tandem mass spectro-metric (LC-MS/MS) method has been developed and validated that employs solid-phase extraction for the simultaneous estimation of amlodipine and valsartan in human K3EDTA plasma using amlodipine-d4 and valsartan-d9 as internal standards. Chromatographic separation of amlodipine and valsartan was achieved on the Luna C18 (2)100A (150 × 4.6 mm, 5 μm) column using acetonitrile: 5 mM ammonium formate solution (80:20, v/v) as the mobile phase at a flow rate of 0.8 mL/min in isocratic mode. Quantification was achieved using an electrospray ion interface operating in positive mode, under multiple reaction monitoring (MRM) conditions. The assay was found to be linear over the range of 0.302–20.725 ng/mL for amlodipine and 6.062–18060.792 ng/mL for valsartan. The method has shown good reproducibility, as intra- and interday precisions were within 10% and accuracies were within 8% of nominal values for both analytes. The method was successfully applied for the bioequivalence study of amlodipine and valsartan after oral administration of a fixed dose of the combination. Additionally, as required by the current regulatory bodies, incurred sample reanalysis was performed and found to be acceptable. PMID:25853070

  8. A rapid and sensitive HPLC-APCI-MS/MS method determination of fluticasone in human plasma: application for a bioequivalency study in nasal spray formulations.

    PubMed

    Byrro, Ricardo Martins Duarte; César, Isabela Costa; de Santana e Silva Cardoso, Fabiana Fernandes; Mundim, Iram Moreira; Teixeira, Leonardo de Souza; Bonfim, Ricardo Rodrigues; Gomes, Sandro Antônio; Pianetti, Gerson Antônio

    2012-03-05

    A sensitive method for the determination of fluticasone in plasma was developed using high performance liquid chromatography with tandem mass spectrometric detection, whereas beclomethasone was used as internal standard. The analytes were extracted with a simple liquid-liquid extraction from the plasma samples and separated on an ACE C(18) 50 × 4.6 mm i.d.; 5 μm particle size column with a mobile phase consisting of acetonitrile - 0.01% formic acid (48:52, v/v) at a flow rate of 1 ml/min. Detection was achieved by an Applied Biosystems API 5000 mass spectrometer (LC-MS/MS) set at unit resolution in the multiple reaction monitoring mode. Atmospheric pressure chemical ionization (APCI) was used for ion production. The mean recovery for fluticasone propionate was 85%, with a lower limit of quantification set at 2 pg/mL. The validated analytical method was applied to a bioequivalence study of fluticasone propionate administered by nasal spray formulations in human volunteers.

  9. Development of an LC-MS/MS method for determination of bicalutamide on dried blood spots: application to pharmacokinetic study in mice.

    PubMed

    P S, Suresh; Vijay Kumar, S; Kumar, Avinash; Mullangi, Ramesh

    2015-02-01

    A rapid and highly sensitive assay method has been developed and validated for the estimation of bicalutamide (BCL) on mouse dried blood spots (DBS) using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the negative-ion mode. The assay procedure involves a simple liquid extraction of BCL and tolbutamide (internal standard, IS) from mouse blood DBS cards using tert-butyl methyl ether. Chromatographic separation was achieved with 5 mm ammonium acetate (pH 6.5)-acetonitrile (35:65, v/v) at a flow rate of 0.60 mL/min on an Atlantis dC18 column with a total run time 3.0 min. The MS/MS ion transitions monitored were 428.80 → 254.70 for BCL and 269.00 → 169.60 for IS. Method validation was performed as per regulatory guidelines. A linear response function was observed from 0.92 to 1911 ng/mL for BCL in mouse blood. The intra- and inter-day precisions were in the ranges of 1.86-12.5 and 3.19-10.8%, respectively. This novel DBS method has been applied to a pharmacokinetic study in mice.

  10. Sensitive method for the determination of rocilinostat in small volume mouse plasma by LC-MS/MS and its application to a pharmacokinetic study in mice.

    PubMed

    Gupta, Manish; Dixit, Abhishek; Devaraj, V C; Zainuddin, Mohd; Bhamidipati, Ravi Kanth; Hallur, Mahanandeesha S; Dewang, Purushottam; Rajagopal, Sridharan; Rajagopal, Sriram; Mullangi, Ramesh

    2016-07-01

    A highly sensitive, specific and rapid LC-ESI-MS/MS method has been developed and validated for the quantification of rocilinostat in small volume mouse plasma (20 μL) using vorinostat as an internal standard (IS) as per regulatory guidelines. Sample preparation was accomplished through a protein precipitation procedure with acetonitrile. Chromatography was achieved on Prodigy ODS-2 column using a binary gradient using mobile phase A (0.2% formic acid in water) and B (acetonitrile) at a flow rate of 0.38 mL/min. The total chromatographic run time was 4.1 min and the elution of rocilinostat and IS occurred at ~3.2 and 2.9 min, respectively. A linear response function was established in the concentration range of 0.28-1193 ng/mL in mouse plasma. The intra- and inter-day accuracy and precisions were in the ranges of 3.12-8.93 and 6.41-11.6%, respectively. This novel method has been applied to a pharmacokinetic study in mice. Copyright © 2016 John Wiley & Sons, Ltd.

  11. Development and validation of an improved method for the quantitation of sertraline in human plasma using LC-MS-MS and its application to bioequivalence studies.

    PubMed

    Zhang, Mengliang; Gao, Feng; Cui, Xiangyong; Zhang, Yunhui; Sun, Yantong; Gu, Jingkai

    2011-02-01

    A rapid and sensitive LC-MS-MS method for the quantitation of sertraline in human plasma was developed and validated. Sertraline and the internal standard, telmisartan, were cleaned up by protein precipitation from 100 μL of plasma sample, and analyzed on a TC-C18 column (5 μm, 150 × 4.6 mm i.d.) using 70% acetonitrile and 30% 10 mM ammonium acetate (0.1% formic acid) as mobile phase. The method was demonstrated to be linear from 0.1 ng/mL to 50 ng/mL with the lower limit of quantitation of 0.1 ng/mL. Intra- and inter-day precision were below 4.40% and 3.55%. Recoveries of sertraline at low, medium, and high levels were 88.0 ± 2.3%, 88.2 ± 1.9%, and 90.0 ± 2.0%, respectively. The method was successfully applied to a bioequivalence study of sertraline after a single oral administration of 50 mg sertraline hydrochloride tablets.

  12. Analysis and pharmacokinetic study of polyphyllin H in beagle dog plasma after oral administration of Rhizoma Paridis extracts by LC-MS/MS.

    PubMed

    Yin, Xingbin; Lin, Longfei; Shen, Mingrui; Zhai, Yujing; Cao, Sali; Fu, Jing; Li, Xuechun; Yang, Chunjing; Xia, Zhenwen; Zhao, Yang; Li, Shangxin; Bai, Ying; Xue, Dan; Ni, Jian

    2014-12-01

    A highly sensitive, rapid assay method has been developed and validated for the analysis of polyphyllin H in beagle dog plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. The assay procedure involves extraction of polyphyllin H and ginsenoside Re (IS) from beagle dog plasma. Chromatographic separation was carried out on an Agilent Zorbax XDB-C18 (100 × 2.1 mm, 1.8μm) column by isocratic elution with acetonitrile and water (50:50, v/v) at a flow rate of 0.25 mL/min with a total run time of 2.5 min. The MS/MS ion transitions monitored were m/z 869.60 → 869.60 for polyphyllin H and m/z 969.60 → 969.60 for IS. [corrected] Linear responses were obtained for polyphyllin H ranging from 1 to 50 ng/mL. The intra-and inter-day precisions (RSDs) <1.77 and 3.39% and the extraction recovery ranged from 91.89 to 93.33% with RSD <2.68%. Stability studies showed that polyphyllin H was stable in the preparation and analytical process. The results indicated that the validated method was successfully used to determine the concentration-time profiles of polyphyllin H.

  13. Development of a LC-MS/MS method for the determination of antrodin B and antrodin C from Antrodia camphorata extract in rat plasma for pharmacokinetic study.

    PubMed

    Liu, Yongli; Di, Xin; Liu, Xingchao; Shen, Wenjin; Leung, Kelvin Sze-Yin

    2010-11-02

    A selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of antrodin B and antrodin C in rat plasma. Both target compounds, together with the internal standard (diazepam), were extracted from rat plasma samples by liquid-liquid extraction with ethyl acetate. Chromatographic separation was carried out on an Agilent XDB-C(8) column with an isocratic mobile phase consisting of acetonitrile and water (70:30, V/V) at a flow rate of 0.5 mL/min. The mass spectrometric detection was performed by selected reaction monitoring (SRM) mode via atmospheric pressure chemical ionization (APCI) source operating in positive ionization mode. The assay exhibited a linear dynamic range of 47.6-4760 ng/mL for antrodin B and 56.6-5660 ng/mL for antrodin C. The intra- and inter-day precision was less than 5.3% and the accuracy was less than 2.7% for both analytes. The validated method has been applied to the pharmacokinetic study of antrodin B and antrodin C in rats following oral administration of Antrodia camphorata extract.

  14. HPLC-MS/MS method for the simultaneous quantification of desmethylmebeverine acid, mebeverine acid and mebeverine alcohol in human plasma along with its application to a pharmacokinetics study.

    PubMed

    Moskaleva, Natalia E; Baranov, Pavel A; Mesonzhnik, Natalia V; Appolonova, Svetlana A

    2017-05-10

    A new simple, rapid and sensitive high pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and validated for simultaneous analysis of mebeverine metabolites as: mebeverine alcohol (MAL), mebeverine acid (MAC) and desmethylmebeverine acid (DMAC) in human plasma. Sample preparation was performed by protein precipitation following the separation of analytes using an Acquity UPLC BEN C8 column 1.7 mm 2.1×50mm (Waters, USA). (2)H5-desmethylmebeverine acid ((2)H5-DMAC) was used as the internal standard (IS). The proposed method was validated with linear ranges of 0.1-10ng/mL; 1-100ng/mL and 5-1000ng/mL for MAL, MAC and DMAC, respectively. Accuracy for all analytes (%RE), given as deviation between nominal and measured concentration and assay variability (CV) ranged from -4.04% to 4.60% and from 0.31% to 6.43% respectively both for within- and between-run. The overall recoveries for all metabolites were above 85%. The proposed method was used successfully for analysis of real samples from a pharmacokinetics study.

  15. Validated LC-MS/MS assay for the quantitative determination of vardenafil in human plasma and its application to a pharmacokinetic study.

    PubMed

    Lake, Simon T; Altman, Phillip M; Vaisman, Jack; Addison, Russell S

    2010-08-01

    A sensitive high-performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) assay has been developed for the quantitative analysis of vardenafil in human plasma. Vardenafil and the internal standard, alprazolam, were extracted from 0.2 mL aliquots of alkalinized plasma by a single solvent extraction into hexane : dichloromethane. Reversed-phase chromatographic separation was affected by gradient elution with mobile phases consisting of 10 mM ammonium formate pH 7.0 (solvent A) and methanol (100%, solvent B), delivered at a flow rate of 0.4 mL/min. The analytes were detected by using an electrospray ion source on a 4000 QTrap triple quadrupole mass spectrometer operating in positive ionization mode. The mass transitions were m/z 489.3 --> 312.2 for vardenafil and m/z 309.2 --> 281.0 for alprazolam. The assay was linear over the concentration range of 0.2-100 ng/mL, with correlation coefficients > or = 0.995. The intra- and inter-day precision was less than 5.4% in terms of relative standard deviation and the accuracy was within 12.7% in terms of relative error. The lower limit of quantitation was set at 0.2 ng/mL. The high sensitivity and acceptable performance of the assay allowed its application to the analysis of plasma samples obtained following the oral administration of vardenafil to healthy male volunteers in a pharmacokinetic study.

  16. Simultaneous determination of ipratropium and salbutamol in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Wu, Jingwen; Ding, Cungang; Ge, Qinghua; Li, Zhou; Zhou, Zhen; Zhi, Xiaojin

    2011-11-15

    A novel, sensitive and specific LC-MS/MS method with silica-based solid-phase extraction was developed for simultaneous determination of ipratropium (IPR) and salbutamol (SAL) in rat plasma. Chromatographic separation was achieved on a Shiseido Capcell Pak CR column (SCX:C(18)=1:4, 150 mm × 2.0 mm, 5 μm) with a mobile phase consisting of methanol/water (85:15, v/v) containing 20 mmol/L ammonium formate and 0.1% formic acid at a flow rate of 0.3 mL/min. A tandem mass spectrometric detection with an electrospray ionization (ESI) interface was conducted via multiple reaction monitoring (MRM) under positive ionization mode. This method was validated in terms of specificity, linearity, accuracy (within ±115.4%), intra- and inter-day precision (<11.4%) over the concentration range of 8-1612 pg/mL for IPR and 50-10,000 pg/mL for SAL. In addition, stability and matrix effects of IPR and SAL in plasma were evaluated. This method has been successfully applied to the pharmacokinetic study of compound ipratropium bromide aerosol mainly containing ipratropium bromide (IB) and salbutamol sulphate (SS) after inhalation in rats.

  17. High-throughput LC-MS/MS assay for 6-methoxy-2-naphthylacetic acid, an active metabolite of nabumetone in human plasma and its application to bioequivalence study.

    PubMed

    Patel, Bhavin N; Sharma, Naveen; Sanyal, Mallika; Prasad, Arpana; Shrivastav, Pranav S

    2008-11-01

    A simple, precise and accurate assay for the determination of 6-methoxy-2-naphthylacetic acid (6-MNA), an active metabolite of nabumetone in human plasma, was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The analyte (6-MNA) and propranolol (internal standard, IS) were extracted from 200 microL aliquot of human plasma via solid-phase extraction employing HLB Oasis cartridges and separated on a Discovery HS C18 (50 x 4.6 mm, 5 microm) column. Detection of analyte and IS was done by tandem mass spectrometry with a turbo ion spray interface operating in positive ion and multiple reaction monitoring acquisition mode. The total chromatographic runtime was 3.0 min with retention time for 6-MNA and IS at 1.97 and 1.26 min, respectively. The method was validated over a dynamic linear range of 0.20-60.00 microg/mL for 6-MNA with mean correlation coefficient r > or = 0.9986. The intra-batch and inter-batch precision (%CV) across five validation runs (lower limit of quantiation, low-, medium- and high-quality controls and upper limit of quantitation) was less than 7.5%. The accuracy determined at these levels was within -5.8 to +0.2% in terms of percentage bias. The method was successfully applied for a bioequivalence study of 750 mg nabumetone tablet formulation in 12 healthy Indian male subjects under fasted condition.

  18. [Validation study on a multi-residue method for determination of pesticide residues in agricultural products by new automatic pretreatment equipment (FASRAC) and GC-MS/MS].

    PubMed

    Okuda, Taiki; Koshi, Naohiro; Matsumura, Atsushi; Yamamoto, Reo; Oyanagi, Tatsuya; Matsuda, Takahiro; Hashimoto, Akihiko; Hatakeyama, Osamu; Kobayashi, Kazuhiro; Nagao, Yasuhiro; Yamada, Toshihiro

    2014-01-01

    A validation study was performed on a multiresidue method for determination of pesticide residues in agricultural products according to the method validation guideline of the Ministry of Health, Labour and Welfare of Japan. FASRAC (Food Automatic Analytical Systems for Residual Agricultural Chemicals) automatically performs extraction of pesticide residues from agricultural products with acetonitrile, filtration, constant volume, mixing with the use of air, mixing acetonitrile with buffer solvent, separation, and dehydration with sodium sulfate. The extract was purified with a GC/NH2 column. For wheat flour and soybeans, a purification step with a C18 column was added before a GC/NH2 column. After removal of the solvent, the extract was resolved in n-hexane/acetone solvent for GC-MS/MS analysis. In the case of manual analysis, pesticide residues were analyzed according to official multiresidue methods and purification steps were the same as in FASRAC. Recovery tests were performed with wheat flour, soybeans, spinach and apples, by addition of 302 pesticides at the concentrations 0.01 mg/kg. The results indicate that automatic extraction using FASRAC is superior to manual analysis in trueness, repeatability and within-run reproducibility. Specially, automatic extraction using FASRAC is superior to manual analysis in trueness because it is optimized in various respects, for example reextraction at salting-out.

  19. An intensive drug monitoring study suggesting possible clinical irrelevance of impaired drug disposition in liver disease.

    PubMed Central

    Naranjo, C A; Busto, U; Janecek, E; Ruiz, I; Roach, C A; Kaplan, K

    1983-01-01

    1 Liver disease can alter the disposition and clinical effects of drugs. However, even though altered drug disposition occurs, there is no clinical evidence relating it to an increased susceptibility to adverse drug reactions (ADRs). 2 An intensive prospective drug monitoring study of 2,582 hospitalized patients was conducted. The adverse drug reactions probability scale (APS) was used to assess ADRs. Only non-mild, definite or probable ADRs (APS greater than or equal to 5) were included. Severity of liver dysfunction was assessed by a composite clinical and laboratory index (CCLI). 3 The frequency of ADRs was higher in 402 patients with cirrhosis (27.4%) than in 661 with renal dysfunction (22.8%) and in 249 with other parenchymatous liver diseases (13.7%) or in 1,270 patients with neither liver diseases nor renal dysfunction (10.9%) (chi 2 3 = 85.53, P less than 0.001). The frequency of ADRs in cirrhotics was highly correlated with the severity of the liver dysfunction measured by CCLI (r = 0.82, P less than 0.001). 4 Drugs predominantly eliminated by liver metabolism were not among those most commonly inducing ADRs or those causing severe reactions in cirrhotics. Thus, frusemide caused the most common and the most severe ADRs, whereas reactions induced by sedatives were uncommon. Drug-induced hepatic encephalopathy was more common in cirrhotics receiving diuretics (13.3%) than in those receiving sedatives (1.8%) (chi 2 y.c. = 5.29, P less than 0.025). Patients with alcoholic liver disease had more drug-induced hepatic encephalopathy (7.7%) than those with non-alcoholic liver disease (1.2%) (chi 2 y.c. = 11.86, P less than 0.001). 5 These results indicate that susceptibility to ADRs is increased only in severe cirrhosis and that the most common and severe ADRs seem more likely related to enhanced pharmacodynamic action than to impaired drug disposition. PMID:6849781

  20. Development and validation of an HPLC-MS/MS analytical method for quantitative analysis of TCBA-TPQ, a novel anticancer makaluvamine analog, and application in a pharmacokinetic study in rats.

    PubMed

    Yu, Jun-Xian; Voruganti, Sukesh; Li, Dan-Dan; Qin, Jiang-Jiang; Nag, Subhasree; Xu, Su; Velu, Sadanandan E; Wang, Wei; Zhang, Ruiwen

    2015-07-01

    We have recently designed and synthesized several novel iminoquinone anticancer agents that have entered preclinical development for the treatment of human cancers. Herein we developed and validated a quantitative HPLC-MS/MS analytical method for one of the lead novel anticancer makaluvamine analog, TCBA-TPQ, and conducted a pharmacokinetic study in laboratory rats. Our results indicated that the HPLC-MS/MS method was precise, accurate, and specific. Using this method, we carried out in vitro and in vivo evaluations of the pharmacological properties of TCBA-TPQ and plasma pharmacokinetics in rats. Our results provide a basis for future preclinical and clinical development of this promising anticancer marine analog.

  1. [Study on the chemical compositions of VOCs emitted by cooking oils based on GC-MS].

    PubMed

    He, Wan-Qing; Nie, Lei; Tian, Gang; Li, Jing; Shao, Xia; Wang, Min-Yan

    2013-12-01

    Volatile organic compounds (VOCs) are key precursors of ozone and secondary organic aerosols in air, and the differences in the compositions of VOCs lead to their different contribution to atmospheric reaction. Cooking oil fume is one of the important sources of atmospheric VOCs, and its chemical compositions are distinct under different conditions of oil types, food types, cooking methods and heating temperatures etc. In this study, the production of cooking oil fume was simulated by heating typical pure vegetable oils (peanut oil, sunflower oil, soybean oil, olive oil and blend oil) at different temperatures in beakers to investigate the chemical compositions of VOCs. The emitted VOCs were sampled with a Tenax adsorption tube and analyzed using GC-MS after thermal desorption. According to spectral library search and map analysis, using area normalized semi-quantitative method, preliminary qualitative and quantitative tests were conducted for the specific components of VOCs under different conditions.

  2. Validated LC-MS/MS method for the determination of 3-hydroxflavone and its glucuronide in blood and bioequivalent buffers: application to pharmacokinetic, absorption, and metabolism studies.

    PubMed

    Xu, Beibei; Yang, Guanyi; Ge, Shufan; Yin, Taijun; Hu, Ming; Gao, Song

    2013-11-01

    The purpose of this study is to develop an UPLC-MS/MS method to quantify 3-hydroxyflavone (3-HF) and its metabolite, 3-hydroxyflavone-glucuronide (3-HFG) from biological samples. A Waters BEH C8 column was used with acetonitrile/0.1% formic acid in water as mobile phases. The mass analysis was performed in an API 5500 Qtrap mass spectrometer via multiple reaction monitoring (MRM) with positive scan mood. The one-step protein precipitation by acetonitrile was used to extract the analytes from blood. The results showed that the linear response range was 0.61-2500.00 nM for 3-HF and 0.31-2500.00 nM for 3-HFG. The intra-day variance is less than 16.5% and accuracy is in 77.7-90.6% for 3-HF and variance less than 15.9%, accuracy in 85.1-114.7% for 3-HFG. The inter-day variance is less than 20.2%, accuracy is in 110.6-114.2% for 3-HF and variance less than 15.6%, accuracy in 83.0-89.4% for 3-HFG. The analysis was done within 4.0 min. Only 10 μl of blood is needed due to the high sensitivity of this method. The validated method was successfully used to pharmacokinetic study in A/J mouse, transport study in the Caco-2 cell culture model, and glucuronidation study using mice liver and intestine microsomes. The applications revealed that this method can be used for 3-HF and 3-HFG analysis in blood as well as in bioequivalent buffers such HBSS and KPI.

  3. Simultaneous Determinations of 17 marker compoundsin Xiao-Chai-Hu-Tang by LC-MS/MS: Application to its Pharmacokinetic Studies in Mice

    PubMed Central

    Sun, Rongjin; Zeng, Min; Du, Ting; Li, Li; Yang, Guangyi; Hu, Ming; Gao, Song

    2015-01-01

    The purpose of this study is to develop and validate an UPLC-MS/MS method to quantify different marker compounds from Xiao-Chai-Hu-Tang (XCHT, a Chinese traditional herbal) in biological samples and apply the method to pharmacokinetic study. A Waters BEH C18UPLC column was used with acetonitrile/0.1% formic acid mobile phases. The mass analysis was performed in a triple quadrupole mass spectrometer using multiple reaction monitoring (MRM) with positive scan mode. A one-step protein precipitation by methanol was used to extract the analytes from blood. Seventeen commercially available compounds from the different compositing herbals were selected as markers. The results revealed that all of the calibration curves showed good linear regression (r2 > 0.9918). The intra-day and inter-day precisions (RSD) of all of these markers at three different levels were less than 15.0% and the bias of the accuracies ranged from −13.5% to 16.6%. The extraction recoveries of all of these 17 markers were from 70.8% to 113.7% and the matrix effects ranged from 71.8% to 114.8%. The stabilities of these compounds in blood were evaluated by analyzing three replicates of QC samples at three different concentrations following storage at 25°C for 6 h, 4°C for 24 h, and −80°C for 30 days. All the samples displayed 85–15% precision and accuracy after various stability tests. The validated method was successfully applied to pharmacokinetic study in A/J mouse with oral administration of XCHT. All of these markers were detected and the pharmacokinetic parameters of 8 compounds were able to be calculated. This method is sensitive and reproducible that can be used for XCHT’s in vivo study. PMID:26397748

  4. Identification of recombinant human EPO variants in greyhound plasma and urine by ELISA, LC-MS/MS and western blotting: a comparative study.

    PubMed

    Timms, Mark; Steel, Rohan; Vine, John

    2016-02-01

    The recombinant human erythropoietins epoetin alfa (Eprex®), darbepoetin (Aranesp®) and methoxy polyethylene glycol-epoetin beta (Mircera®) were administered to greyhounds for 7, 10 and 14 days respectively. Blood and urine samples were collected and analysed for erythropoietin by ELISA, LC-MS/MS and western blotting. Limits of confirmation in plasma for western blotting and LC-MS/MS methods ranged from a low of 2.5mIU/mL, and closely matched the sensitivity of ELISA screening.

  5. Quantitative Determination of ABT-925 in Human Plasma by On-Line SPE and LC-MS/MS: Validation and Sample Analysis in Phase II Studies.

    PubMed

    Wan, Katty; Rieser, Matthew; El-Shourbagy, Tawakol

    2010-05-04

    A fully automated 96-well On-Line Solid Phase Extraction (SPE) followed by High Performance Liquid Chromatography (HPLC)-Tandem Mass Spectrometric (MS/MS) method for the determination of ABT-925 (2-{3-[4-(2-tert-Butyl-6-trifluoromethyl-pyrimidin-4-yl)-piperazin-1-yl)-propyl-sulfanyl}-3H-pyrimidin-4-one fumarate) in human plasma was developed, validated and utilized in Phase II clinical studies. 50 µL of plasma sample was fortified with internal standard (IS, d8-ABT-925) and extracted on-line with Cohesive Turbo Flow Cyclone P HTLC column. The chromatographic separation was performed on Aquasil C18 (3 μm 50 × 3 mm) HPLC column with a mobile phase consisting of 50/50/0.1 (v/v/v) ACN/H₂O/formic acid. The mass spectrometric measurement was conducted under positive ion mode using multiple reaction monitoring (MRM) of m/z 457.4 → 329.4 for analyte and m/z 465.5 → 337.5 for IS.The peak area ratio (analyte/IS) was used to quantitate ABT-925. A dynamic range of 0.0102 μg/mL to 5.24 μg/mL was established after the validation. The validated method was then used for two Phase II studies. To demonstrate the method reproducibility, approximately 10% of the incurred samples from one study were repeated in singlet. The repeated values were compared to the initial values. All repeated values agreed within ±15% of the mean values.

  6. Quantitative Determination of ABT-925 in Human Plasma by On-Line SPE and LC-MS/MS: Validation and Sample Analysis in Phase II Studies

    PubMed Central

    Wan, Katty; Rieser, Matthew; El-Shourbagy, Tawakol

    2010-01-01

    A fully automated 96-well On-Line Solid Phase Extraction (SPE) followed by High Performance Liquid Chromatography (HPLC)-Tandem Mass Spectrometric (MS/MS) method for the determination of ABT-925 (2-{3-[4-(2-tert-Butyl-6-trifluoromethyl-pyrimidin-4-yl)-piperazin-1-yl)-propyl-sulfanyl}-3H-pyrimidin-4-one fumarate) in human plasma was developed, validated and utilized in Phase II clinical studies. 50 µL of plasma sample was fortified with internal standard (IS, d8-ABT-925) and extracted on-line with Cohesive Turbo Flow Cyclone P HTLC column. The chromatographic separation was performed on Aquasil C18 (3 μm 50 × 3 mm) HPLC column with a mobile phase consisting of 50/50/0.1 (v/v/v) ACN/H2O/formic acid. The mass spectrometric measurement was conducted under positive ion mode using multiple reaction monitoring (MRM) of m/z 457.4 → 329.4 for analyte and m/z 465.5 → 337.5 for IS. The peak area ratio (analyte/IS) was used to quantitate ABT-925. A dynamic range of 0.0102 μg/mL to 5.24 μg/mL was established after the validation. The validated method was then used for two Phase II studies. To demonstrate the method reproducibility, approximately 10% of the incurred samples from one study were repeated in singlet. The repeated values were compared to the initial values. All repeated values agreed within ±15% of the mean values. PMID:27721349

  7. Determination of fatty acid ethyl esters in dried blood spots by LC-MS/MS as markers for ethanol intake: application in a drinking study.

    PubMed

    Luginbühl, Marc; Schröck, Alexandra; König, Stefan; Schürch, Stefan; Weinmann, Wolfgang

    2016-05-01

    The forensic utility of fatty acid ethyl esters (FAEEs) in dried blood spots (DBS) as short-term confirmatory markers for ethanol intake was examined. An LC-MS/MS method for the determination of FAEEs in DBS was developed and validated to investigate FAEE formation and elimination in a drinking study, whereby eight subjects ingested 0.66-0.84 g/kg alcohol to reach blood alcohol concentrations (BAC) of 0.8 g/kg. Blood was taken every 1.5-2 h, BAC was determined, and dried blood spots were prepared, with 50 μL of blood, for the determination of FAEEs. Lower limits of quantitation (LLOQ) were between 15 and 37 ng/mL for the four major FAEEs. Validation data are presented in detail. In the drinking study, ethyl palmitate and ethyl oleate proved to be the two most suitable markers for FAEE determination. Maximum FAEE concentrations were reached in samples taken 2 or 4 h after the start of drinking. The following mean peak concentrations (c̅(max)) were reached: ethyl myristate 14 ± 4 ng/mL, ethyl palmitate 144 ± 35 ng/mL, ethyl oleate 125 ± 55 ng/mL, ethyl stearate 71 ± 21 ng/mL, total FAEEs 344 ± 91 ng/mL. Detectability of FAEEs was found to be on the same time scale as BAC. In liquid blood samples containing ethanol, FAEE concentrations increase post-sampling. This study shows that the use of DBS fixation prevents additional FAEE formation in blood samples containing ethanol. Positive FAEE results obtained by DBS analysis can be used as evidence for the presence of ethanol in the original blood sample.

  8. Photofading of ballpoint dyes studied on paper by LDI and MALDI MS.

    PubMed

    Weyermann, Céline; Kirsch, Dieter; Costa-Vera, César; Spengler, Bernhard

    2006-03-01

    The determination of the age of an ink entry from a questioned document is often a major problem and a controversial issue in forensic sciences. Therefore, it is important to understand the aging process of the different components found in ink. The aim of this work is to characterize the degradation processes of methyl violet and ethyl violet, two typical ballpoint dyes by using laser desorption/ionization (LDI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS), and to evaluate the possible application of the method to forensic examination of documents. The mass spectrometric methods were first tested and were found to be adequate for the purpose of this work. Moreover, it is possible to analyze the dye from a stroke directly from the paper (LDI-MS), so the sample preparation is minimized. The degradation of the dyes methyl violet and ethyl violet in strokes from a ballpoint pen was studied under laboratory conditions influenced by different factors such as light, wavelength of light, heat, and humidity. Then, strokes from the same ballpoint were aged naturally in the dark or under the influence of light over one year and then analyzed. The results show that the degradation of these dyes strongly depends on light fluence. Humidity also increases degradation, which can be explained by the basicity of the paper. The influence of heat on the degradation process was found to be rather weak. It was also observed that the dyes from the ink strokes did not show significant degradation after one year of storage in the dark. In conclusion, the storage conditions of a questioned document and the initial composition of the dyes in the ink have to be known for correct interpretation of the age of an ink entry. Measurements over longer periods of time are necessary to follow the degradation of dyes exempt from light exposure. LDI was found adequate and very useful for the analysis of ballpoint dyes directly from paper without further pretreatment.

  9. Application of a UPLC-MS/MS method for the analysis of alosetron in human plasma to support a bioequivalence study in healthy males and females.

    PubMed

    Chaudhary, Darshan V; Patel, Daxesh P; Shah, Jaivik V; Shah, Priyanka A; Sanyal, Mallika; Shrivastav, Pranav S

    2015-10-01

    A simple, rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed and validated for the determination of alosetron (ALO) in human plasma. The assay method involved solid-phase extraction of ALO and ALO 13C-d3 as internal standard (IS) on a LichroSep DVB-HL (30 mg, 1 cm(3) ) cartridge. The chromatography was performed on an Acquity UPLC BEH C18 (50 × 2.1 mm, 1.7 µm) column using acetonitrile and 2.0 mm ammonium formate, pH 3.0 adjusted with 0.1% formic acid (80:20, v/v) as the mobile phase in an isocratic mode. For quantitative analysis, the multiple reaction monitoring transitions studied were m/z 295.1/201.0 for ALO and m/z 299.1/205.1 for IS in the positive ionization mode. The method was validated over a concentration range of 0.01-10.0 ng/mL for ALO. Post-column infusion experiment showed no positive or negative peaks in the elution range of the analyte and IS after injection of extracted blank plasma. The extent of ion-suppression/enhancement, expressed as IS-normalized matrix factor, varied from 0.96 to 1.04. The assay recovery was within 97-103% for ALO and IS. The method was successfully applied to support a bioequivalence study of 1.0 mg alosetron tablets in 28 healthy Indian male and female subjects.

  10. Development of a simple LC-MS/MS method for the determination of febuxostat in human plasma and its application to a bioequivalence study.

    PubMed

    Shi, Zheng; Liu, Jian; Hu, Xing-Jiang; ShenTu, Jian-Zhong

    2013-06-01

    The purpose of this study was to design a simple, sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for a febuxostat bioequivalence study in healthy Chinese male volunteers. In this method, febuxostat and etodolac (internal standard) were isolated from plasma samples by protein precipitation with acetonitrile. The supernatant was chromatographed on a Zorbax SB-C18 (150 x 3.0 mm, 3.5-microm particle size, Agilent) column with a SecurityGuard Inertsil Symmetry C18 column (12.5 x 4.6 mm, 5-microm particle size, Waters). The lower limit of quantification for febuxostat in 0.2 mL of human plasma was 13.40 ng x mL(-1), and the linearity was achieved over a concentration range from 13.40 to 21440 ng x mL(-1). Febuxostat tablets from Hengrui Medicine Co., Ltd (test, Jiangsu, China) and from Takeda pharmaceuticals america, Inc. (reference, Deerfield, IL) were evaluated following a single 80 mg oral dose to 18 healthy volunteers. Bioequivalence was determined by calculating 90% confidence intervals (90% CI) for the ratio of C(max), AUC(0-t), and AUC(0-infinity) values for the test and reference products, using logarithmic transformed data. The calculated 90% CIs for the ratio of C(max) (88.7-131.2%), AUC(0-t) (99.2-122.7%) and AUC(0-infinity) (99.5-123.1%) values for the test and reference products were all located within the bioequivalence criteria range (80-125% for AUC, and 70-143% for Ca(mzax)), proposed by State of Food and Drug Administration [SFDA, 2005. China]. It was concluded that the two febuxostat formulations (test and reference) analyzed were bioequivalent in terms of rate and extent of absorption and the method met the principle of quick and easy clinical analysis.

  11. Simultaneous determination of ledipasvir, sofosbuvir and its metabolite in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Pan, Chenwei; Chen, Yongping; Chen, Weilai; Zhou, Guangyao; Jin, Lingxiang; Zheng, Yi; Lin, Wei; Pan, Zhenzhen

    2016-01-01

    In this work, a rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the determination of ledipasvir, sofosbuvir and its metabolite GS-331007 in rat plasma was developed. The analytes and the internal standard (diazepam) were separated on an Acquity UPLC BEH C18 chromatography column (2.1mm×50mm, 1.7μm) using gradient elution with a mobile phase of acetonitrile and 0.1% formic acid in water at a flow rate of 0.4mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 889.8→130.1 for ledipasvir, m/z 530.3→243.1 for sofosbuvir, m/z 261.5→113.1 for GS-331007 and m/z 285.2→193.1 for diazepam (IS) using a positive electrospray ionization interface. The method was validated over a concentration range of 2-500ng/mL for ledipasvir, 10-2000ng/mL for sofosbuvir and 10-2000ng/mL for GS-331007. Total time for each chromatography was 3.0min. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels exhibited relative standard deviations (RSD)<10.2% and the accuracy values ranged from -9.8% to 11.2%. The method was successfully applied to a pharmacokinetic study of ledipasvir, sofosbuvir and GS-331007 in rats.

  12. A selective and sensitive method based on UPLC-MS/MS for quantification of momordin Ic in rat plasma: application to a pharmacokinetic study.

    PubMed

    Yan, Huiyu; Song, Yanqing; Zhou, Wei; Zhang, Sixi

    2015-11-10

    A selective and sensitive method was developed and validated based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). This method was applied to quantify momordin Ic in rat plasma. Chromatographic separation was performed on a Hypersil GOLD HPLC C18 column (150mm×4.6mm, 5μm) using an isocratic mobile phase of acetonitrile/water (80:20, v/v) at a flow rate of 0.6mL/min. An electrospray ionization source was applied and operated in negative ion mode; selected reaction monitoring (SRM) mode was used for quantification by monitoring the precursor-to-product ion transitions of m/z 763.4→m/z 455.3 for momordin Ic, and m/z 649.4→m/z 487.3 for IS. Calibration curves showed good linearity over the range of 22.0-2200ng/mL for momordin Ic in rat plasma. The developed method was applied to a pharmacokinetic study of momordin Ic in rats after single intravenous doses at 0.52, 1.56, and 4.67mg/kg. The elimination half-life (t1/2) values were 1.22±0.39, 1.14±0.10, and 1.83±0.39h, respectively. The plasma concentration at 2min (C2min) and area under the curve (AUC) for the intravenous doses of momordin Ic were approximately dose proportional.

  13. Simultaneous analysis of oxybutynin and its active metabolite N-desethyl oxybutynin in human plasma by stable isotope dilution LC-MS/MS to support a bioequivalence study.

    PubMed

    Sharma, Primal; Patel, Daxesh P; Sanyal, Mallika; Berawala, Hiren; Guttikar, Swati; Shrivastav, Pranav S

    2013-10-01

    An isotope dilution high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed for the simultaneous determination of oxybutynin and its pharmacologically active metabolite N-desethyl oxybutynin in human plasma. Extraction of oxybutynin, its metabolite and their deuterated analogs as internal standards (ISs) from 300 μL human plasma was carried out by liquid-liquid extraction with methyl tert-butyl ether-ethyl acetate solvent mixture. Chromatographic separation of analytes was performed on Cosmosil C18 (150 mm × 4.6 mm, 5 μm) column under isocratic conditions with acetonitrile-1.0mM ammonium acetate (90:10, v/v) as the mobile phase. Six endogenous plasma phospholipids (496.3/184.0, 524.3/184.0, 758.5/184.0, 786.5/184.0, 806.5/184.0 and 810.5/184.0) were monitored to determine the extraction efficiency under different extraction conditions. The precursor→product ion transition for both the analytes and ISs were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring and positive ionization mode. The method was validated over a concentration range of 0.050-10.0 ng/mL for oxybutynin and 0.500-100 ng/mL for N-desethyl oxybutynin. The mean extraction recovery for analytes (80.4%) and ISs (76.9%) was consistent across five QC levels. Bench top, wet and dry extract, freeze-thaw and long term stability was evaluated for both the analytes. The method was applied to support a bioequivalence study of 5mg tablet formulation in 74 healthy Indian subjects. Assay reproducibility was demonstrated by reanalysis of 344 incurred samples.

  14. Analysis of 21-hydroxy deflazacort in human plasma by UPLC-MS/MS: application to a bioequivalence study in healthy volunteers.

    PubMed

    Patel, Daxesh P; Sharma, Primal; Patel, Bhargav M; Sanyal, Mallika; Singhal, Puran; Shrivastav, Pranav S

    2013-11-01

    A sensitive and rapid ultra performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method has been developed for the determination of 21-hydroxy deflazacort in human plasma using betamethasone as the internal standard (IS). After solid-phase extraction from 100 μL human plasma, the analyte and IS were analyzed on Waters Acquity UPLC BEH C18 (50 mm × 2.1 mm, 1.7 μm) column using acetonitrile-4.0mM ammonium formate, pH 3.5 (90:10, v/v) as the mobile phase. The protonated analyte was quantified by selected reaction monitoring in the positive ionization mode by triple quadrupole mass spectrometer. The calibration plots were linear over the concentration range 0.50-500 ng/mL. Intra-batch and inter-batch precision (% CV) and accuracy (%) for five quality control samples ranged within 1.40-4.82% and 98.0-102.0% respectively. The overall mean extraction recovery of 21-hydroxy deflazacort from plasma ranged from 95.3 to 97.3%. Matrix effect was assessed by post-column analyte infusion and the extraction recovery was >95.0% across four quality control levels for the analyte and IS. Stability was evaluated under different conditions like bench top, autosampler, processed sample (at room temperature and in cooling chamber), freeze-thaw and long term stability. The method was applied to support a bioequivalence study of 30 mg deflazacort tablet formulation in 28 healthy subjects. Assay reproducibility was demonstrated by reanalysis of 115 incurred samples.

  15. Development of an SPE-LC-MS/MS method for simultaneous quantification of bosentan and its active metabolite hydroxybosentan in human plasma to support a bioequivalence study.

    PubMed

    Parekh, Jignesh M; Shah, Dhaval K; Sanyal, Mallika; Yadav, Manish; Shrivastav, Pranav S

    2012-11-01

    A highly sensitive, selective and rapid bioanalytical method has been developed for the simultaneous determination of bosentan and hydroxybosentan in human plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The analytes and their deuterated analogs were quantitatively extracted from 100 μL human plasma by solid phase extraction. The chromatographic separation of analytes was achieved on a Thermo Hypurity C18 (100 mm × 4.6 mm, 5 μ) analytical column with a resolution factor of 2.4 under isocratic conditions. The method was validated over a dynamic concentration range of 0.4-1600 ng/mL for bosentan and 0.2-250 ng/mL for hydroxybosentan. Ion-suppression effects were investigated by post-column infusion of analytes. The precision (%CV) values for the calculated slopes of calibration curves, which would reflect the relative matrix effect, were less than 1.2% for both the analytes. The intra-batch and inter-batch precision (%CV) across quality control levels was ≤4.0% and the mean relative recovery was >94% for both the analytes. The method was successfully applied to a bioequivalence study of 125 mg tablet formulation (test and reference) in 12 healthy Indian male subjects under fasting condition. The ratios of mean log-transformed values of C(max), AUC(0-t) and AUC(0-inf) and their 90% CIs varied from 91.3 to 104.7%. The percentage change for incurred sample reanalysis (ISR) was within ±13.0%.

  16. Simultaneous quantification of lenalidomide, ibrutinib and its active metabolite PCI-45227 in rat plasma by LC-MS/MS: application to a pharmacokinetic study.

    PubMed

    Veeraraghavan, Sridhar; Viswanadha, Srikant; Thappali, Satheeshmanikandan; Govindarajulu, Babu; Vakkalanka, Swaroopkumar; Rangasamy, Manivannan

    2015-03-25

    Efficacy assessments using a combination of ibrutinib and lenalidomide necessitate the development of an analytical method for determination of both drugs in plasma with precision. A high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of lenalidomide, ibrutinib, and its active metabolite PCI45227 in rat plasma. Extraction of lenalidomide, ibrutinib, PCI45227 and tolbutamide (internal standard; IS) from 50 μl rat plasma was carried out by liquid-liquid extraction with ethyl acetate:dichloromethane (90:10) ratio. Chromatographic separation of analytes was performed on YMC pack ODS AM (150 mm × 4.6 mm, 5 μm) column under gradient conditions with acetonitrile:0.1% formic acid buffer as the mobile phases at a flow rate of 1 ml/min. Precursor ion and product ion transition for analytes and IS were monitored on a triple quadrupole mass spectrometer, operated in the selective reaction monitoring with positive ionization mode. Method was validated over a concentration range of 0.72-183.20 ng/ml for ibrutinib, 0.76-194.33 ng/ml for PCI-45227 and 1.87-479.16 ng/ml for lenalidomide. Mean extraction recovery for ibrutinib, PCI-45227, lenalidomide and IS of 75.2%, 84.5%, 97.3% and 92.3% were consistent across low, medium, and high QC levels. Precision and accuracy at low, medium and high quality control levels were less than 15% across analytes. Bench top, wet, freeze-thaw and long term stability was evaluated for all the analytes. The analytical method was applied to support a pharmacokinetic study of simultaneous estimation of lenalidomide, ibrutinib, and its active metabolite PCI-45227 in Wistar rat. Assay reproducibility was demonstrated by re-analysis of 18 incurred samples.

  17. Simultaneous determination of rupatadine and its metabolite desloratadine in human plasma by a sensitive LC-MS/MS method: application to the pharmacokinetic study in healthy Chinese volunteers.

    PubMed

    Wen, Jun; Hong, Zhanying; Wu, Yiwen; Wei, Hua; Fan, Guorong; Wu, Yutian

    2009-02-20

    A sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of rupatadine and its metabolite desloratadine in human plasma. After the addition of diphenhydramine, the internal standard (IS), plasma samples were extracted with a mixture of methyl tert-butyl ether and n-hexane (1:1, v/v). The analysis was performed on a Ultimate AQ-C18 (4.6mm x 100mm, 5microm) column using a mobile phase consisting of a 80/20 mixture of methanol/water containing 0.0005% formic acid pumped at 0.3mlmin(-1). The analytes and the IS were detected in positive ionization mode and monitoring their precursor-->product ion combinations of m/z 416-->309, 311-->259, and 256-->167, respectively, in multiple reaction monitoring mode. The linear ranges of the assay were 0.1-50 and 0.1-20ngml(-1) for rupatadine and desloratadine, respectively. The lower limits of reliable quantification for both rupatadine and desloratadine were 0.1ngml(-1), which offered high sensitivity and selectivity. The within- and between-run precision was less than 7.2%. The accuracy ranged from -9.2% to +6.4% and -7.2% to +7.2% for rupatadine and desloratadine in quality control samples at three levels, respectively. The method has been successfully applied to a pharmacokinetic study of rupatadine and its major metabolite after oral administration of 10, 20 and 40mg rupatadine tablets to healthy Chinese volunteers.

  18. Development and validation of an LC-ESI-MS/MS method for the simultaneous quantification of naproxen and sumatriptan in human plasma: application to a pharmacokinetic study.

    PubMed

    Brêtas, Juliana Machado; César, Isabela Costa; Brêtas, Camila Machado; Teixeira, Leonardo de Souza; Bellorio, Karini Bruno; Mundim, Iram Moreira; Pianetti, Gerson Antônio

    2016-06-01

    A sensitive and fast liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for the simultaneous quantification of naproxen and sumatriptan in human plasma. A simple liquid-liquid extraction procedure, with a mixture of ethyl acetate, methyl tert-butyl ether, and dichloromethane (4:3:3, v/v), was used for the cleanup of plasma. Naratriptan and aceclofenac were employed as internal standards. The analyses were carried out using an ACE C18 column (50 × 4.6 mm i.d.; particle size 5 μm) and a mobile phase consisting of 2 mM aqueous ammonium acetate with 0.025 % formic acid and methanol (38:62, v/v). A triple-quadrupole mass spectrometer equipped with an electrospray source in the positive mode was set up in the selective reaction monitoring mode to detect the ion transitions m/z 231.67 → m/z 185.07, m/z 296.70 → m/z 157.30, m/z 354.80 → m/z 215.00, and m/z 336.80 → m/z 97.94 for naproxen, sumatriptan, aceclofenac, and naratriptan, respectively. The method was validated and proved to be linear, accurate, precise, and selective over the ranges of 2.5-130 μg mL(-1) for naproxen and 1-50 ng mL(-1) for sumatriptan. The validated method was successfully applied to a pharmacokinetic study with simultaneous administration of naproxen sodium and sumatriptan succinate tablet formulations in healthy volunteers.

  19. Simultaneous determination of six flavonoids from Paulownia tomentosa flower extract in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Dai, Bin; Hu, Zhiqiang; Li, Haiyan; Yan, Chong; Zhang, Liwei

    2015-01-26

    A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of six components including apigenin, quercetin, apigenin-7-O-β-D-glucoside, quercetin-3-O-β-D-glucoside, 3'-methoxyluteolin-7-O-β-D-glucoside, and tricin-7-O-β-D-glucopyranoside in rat plasma using formononetin as the internal standard (IS). The plasma samples were pretreated by a one-step liquid-liquid extraction with dichloromethane. The chromatographic separation was carried out on a ZORBAX SB-Aq column with a gradient mobile phase consisting of acetonitrile and 2mM aqueous ammonium acetate. All analytes and IS were quantitated through electrospray ionization in negative ion multiple reaction monitoring mode. The mass transitions were as follows: m/z 269.1→117.2 for apigenin, m/z 301.2→151.2 for quercetin, m/z 431.3→311.2 for apigenin-7-O-β-D-glucoside, m/z 463.2→300.2 for quercetin-3-O-β-D-glucoside, m/z 461.3→283.1 for 3'-methoxyluteolin-7-O-β-D-glucoside, m/z 491.3→313.1 for tricin-7-O-β-D-glucopyranoside, and m/z 267.2→252.2 for IS, respectively. All calibration curves exhibited good linearity with correlation coefficient (r)>0.995. The intra-day and inter-day precisions (RSD) at three QC levels were both less than 14.0% and the accuracies ranged from 89.8% to 113.8%. The extraction recoveries of six compounds ranged from 82.3% to 92.5%. The validated method was successfully applied to pharmacokinetic study of the six components in male rat plasma after oral administration of Paulownia tomentosa flower extract.

  20. A UPLC/MS/MS method for determination of protosappanin B in rat plasma and its application of a pharmacokinetic and bioavailability study.

    PubMed

    Chen, Wei-Ying; Zhou, Xian-Zhen; Wu, Li-Lan; Wu, Yun-Shan; Wang, Shu-Mei; Liu, Bo; Guo, De-An

    2016-12-14

    Caesalpinia sappan L. is a traditional medicinal plant which is used for promoting blood circulation and cerebral apoplexy therapy in China. Previous reports showed that the extracts of Caesalpinia sappan L. could exert vasorelaxant activity and anti-inflammation activity. Protosappanin B is a major constituent of C. sappan L., and showed several important bioactivities. The separation was achieved by an Acquity UPLC BEH Symmetry Shield RP18 column (1.7 μm, 2.1 × 100 mm) column with the gradient mobile phase consisting of 5 mm ammonium acetate aqueous solution and acetonitrile. Detection was carried out by using negative-ion electrospray tandem mass spectrometry via multiple reaction monitoring. Plasma samples were preprocessed by an extraction with ethyl acetate, and apigenin was used as internal standard. The current UPLC-MS/MS assay was validated for linearity, accuracy, intraday and interday precisions, stability, matrix effects and extraction recovery. After oral and intravenous administration, the main pharmacokinetic parameters were as follows: peak concentrations, 83.5 ± 46.2 and 1329.6 ± 343.6 ng/mL; areas under the concentration-time curve, 161.9 ± 69.7 and 264.9 ± 56.3 μg h/L; and half-lives, 3.4 ± 0.9 and 0.3 ± 0.1 h, respectively. The absolute bioavailability in rats of protosappanin B was 12.2%. The method has been successfully applied to a pharmacokinetic and bioavailability study of protosappanin B in rats.

  1. Simultaneous determination of four furostanol glycosides in rat plasma by UPLC-MS/MS and its application to PK study after oral administration of Dioscorea nipponica extracts.

    PubMed

    Liao, Min; Dai, Cong; Liu, Mengping; Chen, Jiefeng; Chen, Zuanguang; Xie, Zhiyong; Yao, Meicun

    2016-01-05

    A novel, sensitive and rapid ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method for simultaneous quantification of four furostanol glycosides in rat plasma was established and validated. Ginsenoside Rb1 was used as an internal standard. Plasma samples were pretreated by liquid-liquid extraction with n-butanol and chromatographed on a C18 column (2.1×50 mm i.d., 2.6 μm) using a gradient elution program consisting of acetonitrile and water (containing 0.03% formic acid and 0.1 mM lithium acetate) at a flow rate of 0.4 mL/min. Lithium adduct ions were employed to enhance the response of the analytes in electrospray positive ionization mode and multiple reaction monitoring transitions were performed for detection. All calibration curves exhibited good linearity (r>0.999) over the range of 10-20,000 ng/mL for protodioscin and 2-4000 ng/mL for protogracillin, pseudoprotodioscin and pseudoprotogracillin. The recoveries of the whole analytes were more than 80.3% and exhibited no severe matrix effect. Meanwhile, the intra- and inter-day precisions were all less than 10.7% and accuracies were within the range of -8.1-12.9%. The four saponins showed rapid excretion and relative high plasma concentrations when the validated method was applied to the PK study of Dioscorea nipponica extracts by intragastric administration at low, medium and high dose to rats. Moreover, the T(1/2) and AUC(0-t) of each compound turned out to behave in a dose-dependent pattern by comparing them at different dose levels.

  2. The use of in vitro technologies coupled with high resolution accurate mass LC-MS for studying drug metabolism in equine drug surveillance.

    PubMed

    Scarth, James P; Spencer, Holly A; Timbers, Sarah E; Hudson, Simon C; Hillyer, Lynn L

    2010-01-01

    The detection of drug abuse in horseracing often requires knowledge of drug metabolism, especially if urine is the matrix of choice. In this study, equine liver/lung microsomes/S9 tissue fractions were used to study the phase I metabolism of eight drugs of relevance to equine drug surveillance (acepromazine, azaperone, celecoxib, fentanyl, fluphenazine, mepivacaine, methylphenidate and tripelennamine). In vitro samples were analyzed qualitatively alongside samples originating from in vivo administrations using LC-MS on a high resolution accurate mass Thermo Orbitrap Discovery instrument and by LC-MS/MS on an Applied Biosystems Sciex 5500 Q Trap.Using high resolution accurate mass full-scan analysis on the Orbitrap, the in vitro systems were found to generate at least the two most abundant phase I metabolites observed in vitro for all eight drugs studied. In the majority of cases, in vitro experiments were also able to generate the minor in vivo metabolites and sometimes metabolites that were only observed in vitro. More detailed analyses of fentanyl incubates using LC-MS/MS showed that it was possible to generate good quality spectra from the metabolites generated in vitro. These data support the suggestion of using in vitro incubates as metabolite reference material in place of in vivo post-administration samples in accordance with new qualitative identification guidelines in the 2009 International Laboratory Accreditation Cooperation-G7 (ILAC-G7) document.In summary, the in vitro and in vivo phase I metabolism results reported herein compare well and demonstrate the potential of in vitro studies to compliment, refine and reduce the existing equine in vivo paradigm.

  3. Development of a LC-MS/MS method to analyze 5-methoxy-N,N-dimethyltryptamine and bufotenine, and application to pharmacokinetic study.

    PubMed

    Shen, Hong-Wu; Jiang, Xi-Ling; Yu, Ai-Ming

    2009-04-01

    INTRODUCTION: 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a psychoactive indolealkylamine substance that has been used for recreational purpose and may lead to fatal toxicity. While 5-MeO-DMT is mainly inactivated via deamination, it is O-demethylated to an active metabolite, bufotenine. Quantitation of 5-MeO-DMT and bufotenine is essential to understand the exposure to and the effects of drug and metabolite. This study, therefore, aimed to develop and validate a LC-MS/MS method for simultaneous analysis of 5-MeO-DMT and bufotenine in mouse serum. METHODS: A simple protein precipitation method coupled with an optimal gradient elution was used for sample preparation and separation. Detection of 5-MeO-DMT and bufotenine was accomplished using multiple reaction monitoring of m/z 219.2→174.2 and 205.2→160.2, respectively, in the positive ion mode. 5-Methyl-N,N-dimethyltrypamine (m/z 203.2→158.3) was used as internal standard for quantification. Accuracy and precision were determined after the analyses of quality control samples. Validated assay was then employed to determine drug and metabolite concentrations in serum samples collected from mice at different time points after intraperitoneal administration of 5-MeO-DMT (2 mg/kg). RESULTS: With a total run time of 9 min, 5-MeO-DMT and bufotenine were eluted at 2.8 and 5.6 min, respectively. The assay was linear over the range 0.90-5,890 ng/mL (1.12-7,360 pg on-column) for 5-MeO-DMT and 2.52-5,510 ng/mL (3.14-6,890 pg) for bufotenine. Intra- and inter-day precision and accuracy were within 15% for both analytes. The recovery of each analyte from 20 µL of serum containing 8.08, 72.7 and 655 ng/mL of 5-MeO-DMT and 7.56, 68.1 and 613 ng/mL of bufotenine was more than 75%. Pharmacokinetic analysis revealed that the systemic exposure (area under the curve) to metabolite bufotenine was about 1/14 of that to 5-MeO-DMT. CONCLUSION: This LC-MS/MS method is a sensitive and reliable assay for quantitation of blood 5-Me

  4. Unraveling the molecular recognition of amino acid derivatives by a pseudopeptidic macrocycle: ESI-MS, NMR, fluorescence, and modeling studies.

    PubMed

    Alfonso, Ignacio; Burguete, M Isabel; Galindo, Francisco; Luis, Santiago V; Vigara, Laura

    2009-08-21

    The binding between a pseudopeptidic macrocyclic naphthalenophane and different N-protected amino acid derivatives has been thoroughly studied by ESI-MS, NMR, fluorescence, and molecular modeling. Careful NMR titration experiments led to the characterization of the intermolecular noncovalent interactions, reflecting a slight side chain and l-stereoselectivity of the host-guest complexes. The data suggest the formation of an intimate ionic pair after the proton transfer from the carboxylic substrate to the amino macrocycle. Additional intermolecular interactions like H-bonding and pi-pi contacts are also important. This receptor shows a stronger interaction with substrates bearing aromatic rings, either in the side chain or in the N-protecting group. Besides, for N-Z-Phe-OH, a moderate enantioselectivity has been observed. Mass spectrometry suggests the formation of supramolecular complexes with stoichiometries higher than 1:1. The dual nature of the fluorescence emission of the macrocyclic receptor allowed determining binding constants and pertinent thermodynamic parameters. On the basis of the experimental data (NMR titrations, intermolecular ROESY, VT-NMR) and with the help of molecular modeling, a reasonable structure for the supramolecular complexes can be proposed, in which the interactions with the naphthyl ring of the receptor play a fundamental role in the strength and selectivity of the molecular recognition event.

  5. A universal surrogate peptide to enable LC-MS/MS bioanalysis of a diversity of human monoclonal antibody and human Fc-fusion protein drug candidates in pre-clinical animal studies.

    PubMed

    Furlong, Michael T; Ouyang, Zheng; Wu, Steven; Tamura, James; Olah, Timothy; Tymiak, Adrienne; Jemal, Mohammed

    2012-08-01

    For the development of human antibody Fc (fraction crystallizable) region-containing therapeutic protein candidates, which can be either monoclonal antibodies (mAbs) or pharmacologically active proteins/peptides fused to the Fc region of human Immunoglobulin G (IgG), reliable quantification of these proteins in animal pharmacokinetic study plasma samples is critical. LC-MS/MS has emerged as a promising assay platform for this purpose. LC-MS/MS assays used for bioanalysis of human antibody Fc region-containing therapeutic protein candidates frequently rely upon quantification of a 'signature' surrogate peptide whose sequence is unique to the protein analyte of interest. One drawback of the signature peptide approach is that a new LC-MS/MS assay must be developed for each new human Fc region-containing therapeutic protein. To address this issue, we propose an alternative 'universal surrogate peptide' approach for the quantification of human antibody Fc region-containing therapeutic protein candidates in plasma samples from all nonclinical species. A single surrogate tryptic peptide was identified in the Fc region of most human antibody Fc-containing therapeutic protein candidates. An LC-MS-MS method based upon this peptide was shown to be capable of supporting bioanalysis of a diversity of human Fc region-containing therapeutic protein candidates in plasma samples of all commonly used animal species.

  6. A Collaborative Study: Determination of Mycotoxins in Corn, Peanut Butter, and Wheat Flour Using Stable Isotope Dilution Assay (SIDA) and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS).

    PubMed

    Zhang, Kai; Schaab, Matthew R; Southwood, Gavin; Tor, Elizabeth R; Aston, Linda S; Song, Wenlu; Eitzer, Brian; Majumdar, Sanghamitra; Lapainis, Theodore; Mai, Huy; Tran, Kevin; El-Demerdash, Aref; Vega, Victor; Cai, Yanxuan; Wong, Jon W; Krynitsky, Alexandra J; Begley, Timothy H

    2017-01-03

    A collaborative study was conducted to evaluate stable isotope dilution assay (SIDA) and LC-MS/MS for the simultaneous determination of aflatoxins B1, B2, G1, and G2; deoxynivalenol; fumonisins B1, B2, and B3; ochratoxin A; HT-2 toxin; T-2 toxin; and zearalenone in foods. Samples were fortified with 12 (13)C uniformly labeled mycotoxins ((13)C-IS) corresponding to the native mycotoxins and extracted with acetonitrile/water (50:50 v/v), followed by centrifugation, filtration, and LC-MS/MS analysis. In addition to certified reference materials, the six participating laboratories analyzed corn, peanut butter, and wheat flour fortified with the 12 mycotoxins at concentrations ranging from 1.0 to 1000 ng/g. Using their available LC-MS/MS platform, each laboratory developed in-house instrumental conditions for analysis. The majority of recoveries ranged from 80 to 120% with relative standard derivations (RSDs) <20%. Greater than 90% of the average recoveries of the participating laboratories were in the range of 90-110%, with repeatability RSDr (within laboratory) < 10% and reproducibility RSDR (among laboratory) < 15%. All Z scores of the results of certified reference materials were between -2 and 2. Using (13)C-IS eliminated the need for matrix-matched calibration standards for quantitation, simplified sample preparation, and achieved simultaneous identification and quantitation of multiple mycotoxins in a simple LC-MS/MS procedure.

  7. An LC-IMS-MS Platform Providing Increased Dynamic Range for High-Throughput Proteomic Studies

    SciTech Connect

    Baker, Erin Shammel; Livesay, Eric A.; Orton, Daniel J.; Moore, Ronald J.; Danielson, William F.; Prior, David C.; Ibrahim, Yehia M.; Lamarche, Brian L.; Mayampurath, Anoop M.; Schepmoes, Athena A.; Hopkins, Derek F.; Tang, Keqi; Smith, Richard D.; Belov, Mikhail E.

    2010-02-05

    A high-throughput approach and platform using 15 minute reversed-phase capillary liquid chromatography (RPLC) separations in conjunction with ion mobility spectrometry-mass spectrometry (IMS-MS) measurements was evaluated for the rapid analysis of complex proteomics samples. To test the separation quality of the short LC gradient, a sample was prepared by spiking twenty reference peptides at varying concentrations from 1 ng/mL to 10 µg/mL into a tryptic digest of mouse blood plasma and analyzed with both a LC-Linear Ion Trap Fourier Transform (FT) MS and LC-IMS-TOF MS. The LC-FT MS detected thirteen out of the twenty spiked peptides that had concentrations ≥100 ng/mL. In contrast, the drift time selected mass spectra from the LC-IMS-TOF MS analyses yielded identifications for nineteen of the twenty peptides with all spiking level present. The greater dynamic range of the LC-IMS-TOF MS system could be attributed to two factors. First, the LC-IMS-TOF MS system enabled drift time separation of the low concentration spiked peptides from the high concentration mouse peptide matrix components, reducing signal interference and background, and allowing species to be resolved that would otherwise be obscured by other components. Second, the automatic gain control (AGC) in the linear ion trap of the hybrid FT MS instrument limits the number of ions that are accumulated to reduce space charge effects, but in turn limits the achievable dynamic range compared to the TOF detector.

  8. Mechanism research on cellulose pyrolysis by Py-GC/MS and subsequent density functional theory studies.

    PubMed

    Wang, Shurong; Guo, Xiujuan; Liang, Tao; Zhou, Yan; Luo, Zhongyang

    2012-01-01

    The mechanism of fast pyrolysis of cellulose has been studied by using an analytical pyrolyzer coupled with a gas chromatography-mass spectrometry set-up (Py-GC/MS). The results showed that the main products comprised pyrans such as levoglucosan and levoglucosenone, furans such as furfural and 5-hydroxymethyl furfural, and linear small molecular chemicals such as acetaldehyde and 1-hydroxy-2-propanone. The compositions of products from fast pyrolysis of cellubiose and glucose were similar to that from cellulose, but with higher furan contents and lower pyran contents. Based on the experimental results, density functional theory (DFT) studies were carried out to deduce the pyrolysis mechanism of cellulose. The results showed the formation of 5-hydroxymethyl furfural from d-glucopyranose unit to be easier than the formation of levoglucosan, in agreement with the experimental results. The deduced mechanism of reaction pathways in cellulose pyrolysis provides insight into the pyrolysis behavior of cellulose and allows modification of previously proposed related mechanisms.

  9. Development of a LC-MS/MS method for simultaneous determination of metoprolol and its metabolites, α-hydroxymetoprolol and O-desmethylmetoprolol, in rat plasma: application to the herb-drug interaction study of metoprolol and breviscapine.

    PubMed

    Rao, Zhi; Ma, Yan-rong; Qin, Hong-yan; Wang, Ya-feng; Wei, Yu-hui; Zhou, Yan; Zhang, Guo-qiang; Wang, Xing-dong; Wu, Xin-an

    2015-09-01

    A simple, specific and sensitive LC-MS/MS method was developed and validated for the simultaneous determination of metoprolol (MET), α-hydroxymetoprolol (HMT) and O-desmethylmetoprolol (DMT) in rat plasma. The plasma samples were prepared by protein precipitation, then the separation of the analytes was performed on an Agilent HC-C18 column (4.6 × 250 mm, 5 µm) at a flow rate of 1.0 mL/min, and post-column splitting (1:4) was used to give optimal interface flow rates (0.2 mL/min) for MS detection; the total run time was 8.5 min. Mass spectrometric detection was achieved using a triple-quadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode. The method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, matrix effect and recovery over a concentration range of 3.42-7000 ng/mL for MET, 2.05-4200 ng/mL for HMT and 1.95-4000 ng/mL for DMT. The analytical method was successfully applied to herb-drug interaction study of MET and breviscapine after administration of breviscapine (12.5 mg/kg) and MET (40 mg/kg). The results suggested that breviscapine have negligible effect on pharmacokinetics of MET in rats; the information may be beneficial for the application of breviscapine in combination with MET in clinical therapy.

  10. Validation of a HPLC-ESI MS/MS method for the determination of clonidine in human plasma and its application in a bioequivalence study in Chinese healthy volunteers.

    PubMed

    Zhuang, Jialang; Chen, Jiangying; Wang, Xueding; Pang, Yin; Bi, Huichang; Huang, Lihui; Zeng, Guixiong; Liao, Xiaoxing; Ma, Zhongfu; Chen, Xiao; Zhong, Guoping; Huang, Min; Zhao, Xianglan

    2015-10-01

    A rapid and sensitive liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method to determine clonidine in human plasma was developed and fully validated. Sample preparation was involved an one-step extraction with diethyl ether. Donepezil was employed as the internal standard (IS). Chromatographic separation was performed on a Hypersil BDS C18 column (i.d. 2.1 × 50 mm, particle size 3μm) with a mobile phase of methanol-water (containing 0.1% formic acid; 60:40, v/v) at a flow rate of 200 μL/min. The peaks were detected by mass spectrometry using the electrospray ion source in selected reaction monitoring mode. The extraction recovery was 72.53-85.25%. The method was found to be linear in a concentration range of 0.02-6.00 ng/mL and the lower limit of quantification was 0.02 ng/mL. The within- and between-batch precisions at three concentrations were 4.33-16.47 and 7.24-17.24% with accuracies of -2.47-10.91 and 1.86-10.19%, respectively. This validated method was successfully used for a bioequivalence study of two clonidine transdermal patches on healthy volunteers. The results suggested that the test formulation of clonidine patch met the regulatory criterion for bioequivalence to the reference formulation, but a larger sample size should be needed for the estimation of bioequivalence.

  11. Quantitative determination of betamethasone sodium phosphate and betamethasone dipropionate in human plasma by UPLC-MS/MS and a bioequivalence study.

    PubMed

    Chen, Man-Yun; Tang, Yong-Jun; Wang, Yi-Cheng; Wang, Chong-Zhi; Yuan, Chun-Su; Chen, Yao; Tan, Zhi-Rong; Huang, Wei-Hua; Zhou, Hong-Hao

    2016-05-07

    The compound medicine of betamethasone sodium phosphate (BSP) and betamethasone dipropionate (BDP) is widely used for diverse glucocorticoid-sensitive acute and chronic diseases such as asthma, rheumatoid arthritis and systemic lupus erythematosus. It will be useful and beneficial to validate sensitive method for the determination of BSP, BDP and their metabolites for their pharmacokinetic study. Hereby, an ultra-high pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been validated for the determination of BSP, BDP and their metabolites betamethasone (BOH), betamethasone 17-monodipropionate (B17P) and betamethasone 21-monodipropionate (B21P) in human plasma. Liquid-liquid extraction with ether and n-hexane (v/v, 4:1) was used for sample preparation of BDP, BOH, B17P and B21P with beclomethasone dipropionate as internal standard (IS), while solid phase extraction was adopted for sample preparation of BSP using prednisolone as IS. The chromatographic separation was performed on a Hypurity C18 column (150 mm×2.1 mm, 5 μm) for BOH, BDP, B21P and B17P, and a Luna C18 (2) column (150 mm×2.0 mm, 5 μm) for BSP. Electrospray ionization interfaced with positive multiple reaction monitoring (MRM) scan mode was used for mass spectrometric detection. The standard calibration curves were linear within the range of 2.525 × 10(-9)-403.9 × 10(-9) mol·dm(-3) for BSP, 0.125 × 10(-9)-55.81 × 10(-9) mol·dm(-3) for BDP, 0.278 × 10(-9)-74.95 × 10(-9) mol·dm(-3) for BOH, 0.098 × 10(-9)-4.688 × 10(-9) mol·dm(-3) for B17P and 0.226 × 10(-9)-5.411 × 10(-9) mol·dm(-3) for B21P, respectively. The validated method was successfully applied to a bioequivalence study in 23 healthy subjects after they were injected with this compound medicine BSP and BDP.

  12. Quantitative analysis of tenuifolin concentrations in rat plasma and tissue using LC⬜MS/MS: application to pharmacokinetic and tissue distribution study.

    PubMed

    Ma, Bo; Li, Xiaotian; Li, Jing; Zhang, Qi; Liu, Yinhui; Yang, Xiaojing; Sun, Jingjing; Yao, Di; Liu, Lei; Liu, Xiaoxin; Ying, Hanjie

    2014-01-01

    A sensitive, reliable and accurate reversed-phased liquid chromatography with tandem mass spectrometry (LC⬜MS/MS) in negative ion mode was developed and validated for the quantification of tenuifolin in rat plasma and tissue. A single step protein precipitation by methanol was used to prepare plasma and tissue homogenate samples. Tenuifolin and polydatin (internal standard, IS) were separated by HPLC using a C18 column and an isocratic mobile phase consisted of acetonitrile and water containing 0.05% formic acid (42:58, v/v) running at a flow rate of 0.2 ml/min for 6 min. Detection and quantification were performed using a mass spectrometer by the multiple reaction monitoring (MRM) in negative electrospray ionization mode. The transition monitored were m/z [M↙H](↙) 679.4 ⠙ 455.4 for tenuifolin and m/z [M↙H](↙) 389.0 ⠙ 227.2 for IS, respectively. Calibration curves were recovered over a concentration range of 0.5⬜1000 ng/ml for plasma, heart, liver, lung and kidney, 0.5⬜200 ng/ml for spleen, and 0.5⬜50 ng/ml for brain, respectively. The lower limit of quantification was 0.5 ng/ml for plasma and tissue homogenates. The inter-day precision (R.S.D.) was less than 12.9% and intra-day precision R.S.D. was less than 13.4%, while the inter-day accuracy (R.E.) was ranged from ↙7.20 to 6.87% and intra-day accuracy (R.E.) was ranged from ↙6.20 to 8.04% in plasma and tissue homogenates. This method was successfully applied to the pharmacokinetic and tissue distribution study of pure tenuifolin in rat. The pharmacokinetic study indicated that poor absorption into systemic circulation was observed after rat was administered orally tenuifolin, and the absolute bioavailability was low (0.83 ± 0.28%). The results of tissue distribution showed the higher tenuifolin concentrations were found in liver, kidney and heart, and the small amount of drug was distributed quickly into the brain tissue at 5 min after the intravenous injection of tenuifolin

  13. Quantitative determination of betamethasone sodium phosphate and betamethasone dipropionate in human plasma by UPLC-MS/MS and a bioequivalence study

    PubMed Central

    Chen, Man-Yun; Tang, Yong-Jun; Wang, Yi-Cheng; Wang, Chong-Zhi; Yuan, Chun-Su; Chen, Yao; Tan, Zhi-Rong; Huang, Wei-Hua; Zhou, Hong-Hao

    2016-01-01

    The compound medicine of betamethasone sodium phosphate (BSP) and betamethasone dipropionate (BDP) is widely used for diverse glucocorticoid-sensitive acute and chronic diseases such as asthma, rheumatoid arthritis and systemic lupus erythematosus. It will be useful and beneficial to validate sensitive method for the determination of BSP, BDP and their metabolites for their pharmacokinetic study. Hereby, an ultra-high pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been validated for the determination of BSP, BDP and their metabolites betamethasone (BOH), betamethasone 17-monodipropionate (B17P) and betamethasone 21-monodipropionate (B21P) in human plasma. Liquid-liquid extraction with ether and n-hexane (v/v, 4:1) was used for sample preparation of BDP, BOH, B17P and B21P with beclomethasone dipropionate as internal standard (IS), while solid phase extraction was adopted for sample preparation of BSP using prednisolone as IS. The chromatographic separation was performed on a Hypurity C18 column (150 mm×2.1 mm, 5 μm) for BOH, BDP, B21P and B17P, and a Luna C18 (2) column (150 mm×2.0 mm, 5 μm) for BSP. Electrospray ionization interfaced with positive multiple reaction monitoring (MRM) scan mode was used for mass spectrometric detection. The standard calibration curves were linear within the range of 2.525 × 10−9−403.9 × 10−9 mol·dm−3 for BSP, 0.125 × 10−9−55.81 × 10−9 mol·dm−3 for BDP, 0.278 × 10−9−74.95 × 10−9 mol·dm−3 for BOH, 0.098 × 10−9−4.688 × 10−9 mol·dm−3 for B17P and 0.226 × 10−9−5.411 × 10−9 mol·dm−3 for B21P, respectively. The validated method was successfully applied to a bioequivalence study in 23 healthy subjects after they were injected with this compound medicine BSP and BDP. PMID:27695531

  14. A highly sensitive and selective LC-MS/MS method to quantify asunaprevir, an HCV NS3 protease inhibitor, in human plasma in support of pharmacokinetic studies.

    PubMed

    Kandoussi, Hamza; Jiang, Hao; Zeng, Jianing; Zheng, Naiyu; Kadiyala, Pathanjali; Eley, Timothy; He, Bing; Garimella, Tushar; Demers, Roger; Cojocaru, Laura; Aubry, Anne-Françoise; Arnold, Mark E

    2016-02-05

    Asunaprevir (BMS-650032) is a selective hepatitis C virus (HCV) NS3 protease inhibitor with potent activity against HCV genotypes 1, 4, 5 and 6. It has been developed in conjunction with direct-acting antiviral agents, in interferon- and ribavirin-free regimen, to improve existing therapies for HCV infection. To support the pharmacokinetic analyses in asunaprevir clinical studies, we have developed and validated a highly sensitive and robust LC-MS/MS method to quantify asunaprevir in human EDTA plasma with an LLOQ of 0.05ng/mL, which was a 20-fold sensitivity improvement over a previously reported assay for asunaprevir. A deuterated labeled [D9]-asunaprevir was used as the internal standard (IS). The analyte and the IS were extracted using a semi-automated liquid-liquid extraction (LLE) at pH 7 with methyl-t-butyl ether (MTBE) in a 96-well plate containing 10μL of 10% CHAPS as the surfactant to prevent non-specific binding issue. Chromatographic separation was achieved on a Genesis C8 column (2.1×50mm, 4μm) with a gradient elution using 0.1% formic acid in water as mobile phase A and a mixture of methanol: acetone: formic acid (95:5:0.1; v/v/v) as the mobile phase B. Positive electrospray ionization was performed using multiple reaction monitoring (MRM) with transitions of m/z 748→648 for asunaprevir and m/z 757→649 for [D9]-asunaprevir,and a collision energy of 30 electron Volts (eV). The assay was validated over a standard curve range from 0.05 to 50ng/mL for asunaprevir in human plasma. The intra- and inter assay precisions were within 7.1% CV, and the % deviation was within 5.5% of their nominal concentrations. This assay has been successfully applied to multiple clinical studies with excellent assay ruggedness and reproducibility.

  15. Pyrolysis GC-MS and NMR studies of humics in contaminated sediments

    SciTech Connect

    Higashi, R.M.; Fan, T.W.M.; Lane, A.N.

    1994-12-31

    Sediment ``humics`` play a major role in sorption and chemical reactions of organic and metal pollutants, as well as of nutrients, detritus, and other naturally-occurring chemicals. Not surprisingly, the chemical structure of humics is very important in this regard. The problem is, humics are among the most complex and least-understood substances in the world. This is because the primary structure is heterologous, unlike most other macromolecules which are polymeric; thus, researchers could not obtain coherent structures to identify with properties. However, recent advances in NMR spectroscopy and pyrolysis GC-MS have enabled researchers to begin relating primary and higher order structural motifs germane to the chemistry of the refractory humics. The authors have explored various means of sediment extraction for humics analysis by these techniques, including direct analysis of unextracted sediments. Marine sediments from near produced water discharges, salt marshes, and dredge material were surveyed. The study has revealed interpretive pitfalls, depending on the method of humic extraction. These difficulties are expected since the approach is at its infancy, but the overall approach is clearly useful in probing the humic structure profile of marine sediments.

  16. Kinetic Intermediates of Holo- and Apo-Myoglobin Studied Using HDX-TIMS-MS and Molecular Dynamic Simulations

    NASA Astrophysics Data System (ADS)

    Schenk, Emily R.; Almeida, Raybel; Miksovska, Jaroslava; Ridgeway, Mark E.; Park, Melvin A.; Fernandez-Lima, Francisco

    2015-04-01

    In the present work, the kinetic intermediates of holo- and apo-myoglobin were studied by correlating the ion-neutral collision cross section and time resolved H/D back exchange rate simultaneously in a trapped ion mobility spectrometer coupled to a mass spectrometer (HDX-TIMS-MS). The high mobility resolution of the TIMS cell permitted the observation of multiple IMS bands and complementary molecular dynamics simulations resulted in the assignment of candidate structures for each experimental condition studied (e.g., holo [M + 8H]+8-[M + 9H]+9 and apo [M + 9H]+9-[M + 19H]+19). Inspection of the kinetic intermediates suggests that the tertiary structure of apomyoglobin unfolds quickly upon the loss of the Fe protoporphyrin IX that stabilizes the interactions between the A, G, and H helices. In the absence of the porphyrin heme, the apomyoglobin unfolds to Xn kinetic intermediates that vary in the extent of unfolding as a result of the observed charge state.

  17. Development of a LC-MS/MS method for quantification of two pairs of isomeric flavonoid glycosides and other ones in rat plasma: Application to pharmacokinetic studies.

    PubMed

    Zhang, Sixi; Xie, Yang; Wang, Jing; Geng, Yanmei; Zhou, Yu; Sun, Chengxin; Wang, Guangshu

    2017-03-10

    An liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of six flavonoid glycosides including isoorientin (1), orientin (2), 2″-O-β-D-xylopyranosyl isoorientin (3), 2″-O-β-D-xylopyranosyl isovitexin (4), 6-C-L-α-arabipyranosyl vitexin (5), and vitexin (6) in rat plasma using isoquercitrin as the internal standard (IS). Plasma samples were prepared by a one-step protein precipitation with acetonitrile. Chromatographic analysis was carried out on a 25-cm C18 column with a gradient mobile phase consisting of acetonitrile and 0.1% aqueous formic acid. Six analytes and IS were detected through electrospray ionization in negative-ion selection reaction monitoring mode. The mass transitions were as follows: m/z 447.2 → 327.0 for 1, m/z 447.2 → 327.0 for 2, m/z 579.3 → 458.9 for 3, m/z 563.0 → 293.1 for 4, m/z 563.0 → 353.0 for 5, m/z 431.1 → 311.1 for 6, and m/z 463.1 → 300.2 for IS, respectively. Calibration curves exhibited good linearity (r(2)  > 0.9908) over a wide concentration range for all compounds. Intra-day and inter-day precision (RSD%) at four different levels were both less than 14.2% and the accuracy (RE%) ranged from -11.9% to 12.0%. The extraction recoveries of the six components ranged from 88.2% to 103.6%. The validated assay was successfully applied to the pharmacokinetic studies of the six components in male rat plasma after intravenous administration of total flavonoids of Scorzonera austriaca Wild.

  18. Simultaneous determination of harmine, harmaline and their metabolites harmol and harmalol in beagle dog plasma by UPLC-ESI-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Zhang, Lei; Teng, Liang; Gong, Can; Liu, Wei; Cheng, Xuemei; Gu, Shenghua; Deng, Zhongping; Wang, Zhengtao; Wang, Changhong

    2013-11-01

    Harmine (HAR) and harmaline (HAL) were metabolized by demethylation to form harmol (HOL) and harmalol (HAM) both in vivo and in vitro. It has been demonstrated tremendous value of HAR, HAL and their metabolites in the therapy of Alzheimer's disease. A rapid, selective and sensitive UPLC-ESI-MS/MS method was firstly developed and validated for the simultaneous determination of HAR, HAL, HOL, and HAM in beagle dog plasma with 9-aminoacridine as the internal standard (IS). After protein precipitation with acetonitrile, the analytes were separated within 4.5 min on an ACQUITY UPLC BEH C18 column with a gradient elution system composed of 0.1% formic acid and acetonitrile at a flow rate of 0.4 ml/min. Detection was performed using multiple reactions monitoring mode under a positive ionization condition. The calibration curves of four analytes showed good linearity (r(2)>0.9959) within the tested concentration ranges. The low limit of quantification for HAR, HAL, HOL, and HAM were all 1.00 ng/ml. The mean accuracy of the analytes was within the range of 94.56-112.23%, the R.S.D. values of intra-day and the inter-day precision were less than 6.26% and 7.51%, respectively. Matrix effects and extraction recoveries of the analytes from the beagle dog plasma were within the range of 94.48-105.77% and 89.07-101.44%, respectively. The validated method was successfully applied to a pharmacokinetic study of HAR, HAL, HOL, and HAM in beagle dogs after intravenous administration of HAR and HAL both of 1.0mg/kg. The main pharmacokinetic parameters of Cmax, Vd, CL, AUC and MRT, except Ke and t1/2 values, showed significant difference between the two parent drug HAR and HAL, respectively (p<0.05-0.001). Because of the different metabolic rate of HAR and HAL in vivo, the two metabolites, HOL and HAM, exhibited unique pharmacokinetic properties.

  19. Simultaneous Determination of Bosentan, Glimepiride, HYBOS and M1 in Rat Plasma by UPLC-MS-MS and its Application to Pharmacokinetic Study.

    PubMed

    Chen, Mengchun; Song, Wenjie; Wang, Shuanghu; Chen, Qiulei; Pan, Peipei; Xu, Tao; Hu, Guoxin; Zheng, Zhiqiang

    2016-08-01

    A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method for the simultaneous determination of bosentan (BOS), glimepiride (GLP), hydroxyl bosentan (HYBOS) and hydroxyl glimepiride (M1) in rat plasma using one-step protein precipitation was developed and validated. After addition of ambrisentan as an internal standard (IS), protein precipitation by acetonitrile was used in sample preparation. Chromatographic separation was achieved on a Waters ACQUITY UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm particle size, Waters Corp., Milford, MA, USA) and inline 0.2 μm stainless steel frit filter (Waters Corp.) with acetonitrile-0.1% formic acid as the mobile phase at a flow rate of 0.4 mL/min with gradient elution. The column temperature was maintained at 40°C. Only 4 min was needed for an analytical run. The retention times were ∼3.29 min for BOS, 3.56 min for GLP, 1.42 min for HYBOS, 1.53 min for M1 and 3.22 min for IS. Electrospray ionization source was employed and operated in positive-ion mode; multiple reaction monitoring mode was applied to target fragment ions m/z 552 → 202, m/z 568 → 202, m/z 491 → 352, m/z 507 → 352 and m/z 379 → 347 for BOS, HYBOS, GLP, M1 and IS, respectively. The assay was validated over concentration ranges of 25-5,000 ng/mL (r(2) = 0.9984) for BOS, 1-200 ng/mL (r(2) = 0.9999) for GLP, 0.5-100 ng/mL (r(2) = 0.9999) for HYBOS and 0.1-20 ng/mL (r(2) = 0.9984) for M1. Intra- and interday precision values for replicate quality control samples were within 14.2% for all analytes during the assay validation. Mean quality control accuracy values were within -3.3 to 14.4% of nominal values for all analytes. The mean recoveries of BOS, GLP, HYBOS, M1 and ambrisentan from the plasma exceeded 90.4%. The analytes were stable in rat plasma for at least 2 h at room temperature, 30 days at -40°C and following at least three freeze-thaw cycles (-40°C to room temperature). This method was

  20. Simultaneous determination of andrographolide, dehydroandrographolide and neoandrographolide in dog plasma by LC-MS/MS and its application to a dog pharmacokinetic study of Andrographis paniculata tablet.

    PubMed

    Xu, Fang-fang; Fu, Shu-jun; Gu, Sheng-pan; Wang, Zhi-min; Wang, Zhen-zhong; He, Xin; Xiao, Wei

    2015-05-15

    In this study, a sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determinate andrographolide (AP), dehydroandrographolide (DP), and neoandrographolide (NP) in plasma of beagle dogs after oral administration of Andrographis paniculata tablet (A. paniculata). The analytes and bilobalide (internal standard) were separated on an Agilent ZORBAX XDB-C18 column (50mm×2.1mm, 3.5μm) by using gradient elution consisting of methanol and water at a flow rate of 0.50mL/min in 7min. Multiple reaction monitoring (MRM) mode was performed to quantify data under monitoring precursor-product ion transitions of m/z 348.8→286.9, 330.9→107.9, 479.1→160.8 and 325.0→163.0 for AP, DP, NP and internal standard (IS) at negative ion mode, respectively. This method was developed at linearity ranging from 0.50 to 250ng/mL for AP, 1.00 to 500ng/mL for DP and 0.20 to 100ng/mL for NP. The accuracy of each analyte ranged between 94.8% and 107.1% and the precision was within 14.6%. No significant matrix effect was observed. AP, DP and NP were stable during sample storage, preparation and analytic procedures. Furthermore, this method was successfully applied in the investigation of the pharmacokinetic profile of AP, DP and NP in beagle dogs after oral administration of A. paniculata tablet (49.5mg for AP, 7.0mg for DP, 22.0mg for NP). Biological half-life (t1/2) was 2.08±0.99, 3.13±1.19 and 1.07±0.38h for AP, DP and NP, respectively. The areas under curves (AUC0-t) of AP, DP and NP was 494.50±150.64, 26.01±8.72 and 78.78±18.29ngh/mL, respectively.

  1. Studying the effect of storage conditions on the metabolite content of red wine using HILIC LC-MS based metabolomics.

    PubMed

    Arapitsas, Panagiotis; Corte, Anna Della; Gika, Helen; Narduzzi, Luca; Mattivi, Fulvio; Theodoridis, Georgios

    2016-04-15

    The main aim of this work was to develop an untargeted normal phase LC-MS method, starting from a targeted method already validated for the analysis of 135 polar metabolites. Since the LC instrument and column were the same, most of the chromatographic conditions remained identical, while the adaptations focused on maintaining the ionic strength of the eluents constant. The sample preparation was simplified and the effectiveness of LC-MS for long batches was evaluated, in order to record the maximum number of metabolites with good chromatographic resolution and the best MS stability and accuracy. The method was applied to study the influence of storage conditions on wine composition. Slightly sub-optimum storage conditions had a major impact on the polar metabolite fingerprint of the red wines analysed and the markers revealed included phenolics, vitamins and metabolites indentified in wine for the first time (4-amino-heptanedioic acid and its ethyl ester).

  2. Design Study of an Atmospheric Pressure Photoionization Interface for GC-MS

    NASA Astrophysics Data System (ADS)

    Kersten, Hendrik; Kroll, Kai; Haberer, Kirsten; Brockmann, Klaus J.; Benter, Thorsten; Peterson, Amelia; Makarov, Alexander

    2016-04-01

    This contribution reports on the development of an atmospheric pressure photoionization (APPI) source interfacing a gas chromatograph (GC) with a bench-top Orbitrap high resolution mass spectrometer (MS). We present efforts on method development aiming at high temperature stability (325°C), constant low impurity levels upon prolonged source operation, and efficient reaction volume irradiation combined with minimum peak broadening. The performance throughout each iterative development step was carefully assessed. The final GC-APPI-MS setup demonstrated femtogram-on-column sensitivity and chromatographic peaks of Gaussian shape with base peak widths <2 s for even the highest boiling compounds present in different EPA standard mixtures.

  3. VALIDATION STUDIES OF THERMAL EXTRACTION-GC/MS APPLIED TO SOURCE EMISSIONS AEROSOLS: 1. SEMIVOLATILE ANALYTE--NONVOLATILE MATRIX INTERACTIONS

    EPA Science Inventory

    This work develops a novel validation approach for studying how non-volatile aerosol matrices of considerably different chemical composition potentially affect the thermal extraction (TE)/GC/MS quantification of a wide range of trace semivolatile organic markers. The non-volatil...

  4. MS 1512 cB58: A case study of star formation, metal enrichment and superwinds in Lyman break galaxies

    NASA Astrophysics Data System (ADS)

    Pettini, Max; Rix, Samantha A.; Steidel, Chuck C.; Hunt, Matthew P.; Shapley, Alice E.; Adelberger, Kurt L.

    2002-07-01

    Recent advances in instrumentation and observing techniques have made it possible to begin to study in detail the stellar populations and the interstellar media of galaxies at redshift z = 3, when the universe was still in its ‘teen years’. I illustrate recent progress in this field with the latest observations of the gravitationally lensed galaxy MS 1512- cB58.

  5. NLRP3 Inflammasome and MS/EAE

    PubMed Central

    Shinohara, Mari L.

    2013-01-01

    Inflammasomes are cytosolic sensors that detect pathogens and danger signals in the innate immune system. The NLRP3 inflammasome is currently the most fully characterized inflammasome and is known to detect a wide array of microbes and endogenous damage-associated molecules. Possible involvement of the NLRP3 inflammasome (or inflammasomes) in the development of multiple sclerosis (MS) was suggested in a number of studies. Recent studies showed that the NLRP3 inflammasome exacerbates experimental autoimmune encephalomyelitis (EAE), an animal model of MS, although EAE can also develop without the NLRP3 inflammasome. In this paper, we discuss the NLRP3 inflammasome in MS and EAE development. PMID:23365725

  6. Government in Emergency. Suggestions for Including Civil Defense Principles in the Social Studies Curriculum, Grades 1-12.

    ERIC Educational Resources Information Center

    Office of Civil Defense (DOD), Washington, DC.

    This handbook contains suggestions for teaching the facts, principles, and behaviors relevant to civil defense in social studies classes, grades 1-12. These classes were chosen as the entry point for civil defense education because the core of the civil defense concept is government in action with other community agencies to save lives and…

  7. The Translucent Cadaver: A Follow-up Study to Gauge the Efficacy of Implementing Changes Suggested by Students

    ERIC Educational Resources Information Center

    Kotzé, Sanet Henriët; Driescher, Natasha Darné; Mole, Calvin Gerald

    2013-01-01

    In a study conducted in 2011, the use of full body digital X-ray images (Lodox® Statscan®) and drawings were described for surface anatomy education during which suggestions were made by students on how to improve the method. Educational innovations should continuously be adjusted and improved to provide the best possible scenario for student…

  8. Selenium transformation studies during broccoli (Brassica oleracea) growing process by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS).

    PubMed

    Pedrero, Zoyne; Elvira, Daniel; Cámara, Carmen; Madrid, Yolanda

    2007-07-23

    Selenium uptake and transformation was studied in Se-enriched Broccoli (Brassica olearacea). Plants were grown in hydroponic culture and exposed during 40 days to Na2SeO3 (1 mg L(-1)). After growing, the plants were harvested and their different parts (roots, stems and fruit) were analyzed by ICP-MS or LC-ICP-MS. Se-species were identified and quantified after enzymatic extraction by using both an anion exchange (PRP-X100), and a size exclusion/ion exchange (Shodex Asahipak) chromatographic columns. Selenium translocation and transformation Se species in plants was studied through the Se-speciation in root, stem and fruit. After 40 days of exposure, selenomethionine was the major species found in roots, however, Se-methylselenocysteine was the main species found in the fruit, suggesting Broccoli as a source of this important selenoamino acid in human diet. However, the degree of meal processing influences the stability of Se-aminoacids. Speciation studies in boiled Broccoli and in the extraction water were also carried out. This experiment revealed a noticeable degradation of Se-methylselenocysteine in the boiled Broccoli fruit. Proteins soluble in Tris-HCl were analyzed by two-dimensional chromatography coupled to ICP-MS. The results obtained contribute not only to a deeper understanding of Se accumulation mechanisms by plants but also to further functional food complements preparation and the effect of food processing on species stability.

  9. Open to Suggestion.

    ERIC Educational Resources Information Center

    Journal of Reading, 1987

    1987-01-01

    Offers (1) suggestions for improving college students' study skills; (2) a system for keeping track of parent, teacher, and community contacts; (3) suggestions for motivating students using tic tac toe; (4) suggestions for using etymology to improve word retention; (5) a word search grid; and (6) suggestions for using postcards in remedial reading…

  10. Characterization of stress degradation products of duloxetine hydrochloride employing LC-UV/PDA and LC-MS/TOF studies.

    PubMed

    Chadha, Renu; Bali, Alka; Bansal, Gulshan

    2016-03-20

    Duloxetine HCl was subjected to forced degradation under conditions of hydrolysis (neutral, acidic and alkaline), oxidation, photolysis and thermal stress, as suggested in the ICH guideline Q1A(R2). The drug showed significant degradation under acidic, alkaline and aqueous hydrolytic as well as photolytic conditions. The drug remained stable under thermal and oxidative stress conditions. In total, seventeen degradation products (I-XVII) were formed under varied conditions, which could be separated by chromatography of respective degraded solutions on C18 (250 mm×4.6 mm; 5 μ, Nulceodur) column using isocratic elution method. Detection wavelength was selected as 290 nm. MS/TOF accurate mass studies were carried out to establish the complete fragmentation pathway of the drug and degradation products, which, in turn, was utilized in characterization of the products. The degradation pathway of the drug leading to generation of fifteen products I-X, XII-XIII, XV-XVII was postulated and this has not been reported so far.

  11. Photostability of alpha-tocopherol ester derivatives in solutions and liposomes. Spectroscopic and LC-MS studies.

    PubMed

    Neunert, Grazyna; Szwengiel, Artur; Walejko, Piotr; Witkowski, Stanislaw; Polewski, Krzysztof

    2016-07-01

    α-Tocopherol (Toc) is known to degrade to the tocopheroxyl radicals (Toc) by exposure to UV light irradiation. In the present study, the stability of Toc ester derivatives exposed to UV light was investigated and compared with Toc in organic solution and in phospholipid vesicles. To follow the depletion of Toc and its esters the absorbance and fluorescence methods were applied whereas degradation products were detected using LC-MS method. The irradiation with UVB light of air-equilibrated solutions of di-α-Tocopheryl malonate (DTMO), α-Tocopheryl malonate (TMO) and α-Tocopheryl succinate (TS) strongly modifies their absorption and fluorescence spectra. Upon UVB irradiation, absorption band at 279/285nm becomes less pronounced indicating the photodegradation of esters. During irradiation, the fluorescence maximum of esters at 305nm shifts to 326nm, a maximum characteristic for Toc. Photorecovery of Toc from its esters derivatives was finally confirmed by LC-MS method. Among studied esters, only α-tocopheryl nicotinate (TN) did not undergo depletion and appeared resistant to UVB radiation. Kinetic studies indicated that photoinduced transformation occurs through the first order consecutive reaction chain mechanism. The photodissociation of Toc esters in the liposomes occurred with one order of magnitude slower than in organic solvents. Using MS/MS method it was found that final stable product of irradiation was α-tocopheryl quinone (TQ), an animal and plant metabolite of Toc.

  12. Study of spontaneous combustion coals by GC and GC-MS.

    PubMed

    Shu, X; Xu, J; Xu, J; Ge, L; Chen, D

    1996-06-01

    Organic geochemical characteristics of 3 Chinese spontaneous combustion coals have been carried out by means of GC and GC-MS analysis. It has been observed that more compounds with low to medium carbon number, such as terpenoids and others can be found in spontaneous combustion coals than in normal samples.

  13. Biosynthesis of castor oil studied by the regiospecific analysis of castor triacylglycerols by ESI-MS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    HPLC fractions of diricinoleoyl-acyl-glycerols containing one non-ricinoleoyl chain from castor oil were used to identify the regiospecific location of this non-ricinoleoyl chain on the glycerol backbone using electrospray ionization-MS3 of lithium adducts. The regiospecific ions used were from the ...

  14. A rapid LC-ESI-MS/MS method for the quantitation of choline, an active metabolite of citicoline: Application to in vivo pharmacokinetic and bioequivalence study in Indian healthy male volunteers.

    PubMed

    Sarkar, Amlan Kanti; Ghosh, Debotri; Haldar, Dhiman; Sarkar, Pradipta; Gupta, Bhaswati; Dastidar, Sujata Ghosh; Pal, Tapan Kumar

    2012-12-01

    A rapid, simple, and sensitive high performance liquid chromatography-tandem mass spectrometry method (LC-ESI-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of choline (CL), active metabolite of citicoline in human plasma using metformin (MF) as IS. The chromatographic separation was performed on a reversed-phase Phenomenx Gemini C18 column with a mobile phase of methanol:water (containing 10mM ammonium formate) (9:1, v/v). The calibration curves were linear over the range of 0.05-5μg/ml. The validated LC-ESI-MS/MS method was successfully applied for the evaluation of pharmacokinetic parameters and bioequivalence study of test and reference control release (CR) tablet preparation of citicoline 1000mg after a single oral administration to all 12 healthy male volunteers.

  15. Development and validation of an HPLC-MS/MS analytical method for quantitative analysis of TCBA-TPQ, a novel anticancer makaluvamine analog, and application in a pharmacokinetic study in rats

    PubMed Central

    Jun-Xian, YU; Voruganti, Sukesh; Dan-Dan, LI; Qin, Jiang-Jiang; Nag, Subhasree; Xu, Su; Velu, Sadanandan E.; Wang, Wei; Zhang, Ruiwen

    2016-01-01

    We have recently designed and synthesized several novel iminoquinone anticancer agents that have entered preclinical development for the treatment of human cancers. Herein we developed and validated a quantitative HPLC-MS/MS analytical method for one of the lead novel anticancer makaluvamine analog, TCBA-TPQ, and conducted a pharmacokinetic study in laboratory rats. Our results indicated that the HPLC-MS/MS method was precise, accurate, and specific. Using this method, we carried out in vitro and in vivo evaluations of the pharmacological properties of TCBA-TPQ and plasma pharmacokinetics in rats. Our results provide a basis for future preclinical and clinical development of this promising anticancer marine analog. PMID:26233847

  16. Comparative study of antioxidant properties and total phenolic content of the extracts of Humulus lupulus L. and quantification of bioactive components by LC-MS/MS and GC-MS.

    PubMed

    Önder, Ferah Cömert; Ay, Mehmet; Sarker, Satyajit D

    2013-11-06

    In this research, antioxidant activities of various extracts obtained from Humulus lupulus L. were compared by DPPH, ABTS, FRAP, and CUPRAC assays. The amount of total phenolic components determined by the Folin-Ciocalteu reagent was found to be highest for 25% aqueous ethanol (9079 ± 187.83 mg Ferulic acid equivalent/100 g extract) and methanol-1 (directly) (8343 ± 158.39 mg Ferulic acid equivalent/100 g extract) extracts. The n-hexane extract of H. lupulus exhibited the greatest with DPPH (14.95 ± 0.03 μg Trolox equivalent/g sample). The highest phenolic content in the ethanolic extract could be the major contributor to its highest CUPRAC activity (3.15 ± 0.44 mmol Trolox equivalent/g sample). Methanol-2 (n-hexane, acetone, and methanol) and methanol-3 (n-hexane, dichloromethane, ethylacetate, and methanol) extracts, respectively, exhibited the most potent ABTS (7.35 ± 0.03 mM Trolox equivalent) and FRAP (1.56 ± 0.35 mmol Fe(2+)/g sample) activities. Some of the components from the crude extracts were determined by LC-MS/MS and GC-MS analyses. Comparative screening of antioxidant activities of H. lupulus extracts and quantification of some major components by LC-MS/MS, qualitatively analysis of the reported ones which were optimal under negative ion SIM mode and coinjection, are going to be valuable for food and health applications.

  17. Impact history of the Chelyabinsk meteorite: Electron microprobe and LA-ICP-MS study of sulfides and metals

    NASA Astrophysics Data System (ADS)

    Andronikov, A. V.; Andronikova, I. E.; Hill, D. H.

    2015-12-01

    Electron microprobe and LA-ICP-MS study of sulfides and metals from two fragments of the LL5 Chelyabinsk meteorite were conducted. The fragments are impact breccias, one fragment contains both chondritic and shock vein lithologies, and the other contains shock-darkened chondritic clasts and vesicular impact melts. The chondritic lithology and shock veins display very similar opaque mineral compositions. The mineral compositions in the impact-melt breccias are distinctly different. The brecciated state of the Chelyabinsk meteorite suggests strong involvement of shock-related processes during the evolution of the parent body. Multiple heavy impact events occurred on the parent asteroid and on the Chelyabinsk meteoroid itself over the time period from ca. 4.5 Ga until ca. 1.2 Ma. The shock veins were produced in situ on the parent body. The impact-melt breccias could have formed because of the dramatic impact to the parent LL-chondrite body that could be partly disintegrated. The fragment containing shock-darkened chondritic clasts and vesicular impact melt lithologies preserves a record of melting, volatilization, partial degassing, and quenching of the molten material. The abundance and size (up to 1 mm) of the vesicles suggest that the impact melt must have been buried at some depth after formation. After impact and subsequent melting occurred, the impact-induced pressure on the shallow asteroid interior was released that caused "boiling" of volatiles and generation of S-rich bubbles. Such an impact excavated down to depths of the body generating multiple fragments with complicated histories. These fragments reaccumulated into a gravitational aggregate and formed the parental meteoroid for the Chelyabinsk meteorite.

  18. Ecological Epigenetics: Beyond MS-AFLP.

    PubMed

    Schrey, Aaron W; Alvarez, Mariano; Foust, Christy M; Kilvitis, Holly J; Lee, Jacob D; Liebl, Andrea L; Martin, Lynn B; Richards, Christina L; Robertson, Marta

    2013-08-01

    Ecological Epigenetics studies the relationship between epigenetic variation and ecologically relevant phenotypic variation. As molecular epigenetic mechanisms often control gene expression, even across generations, they may impact many evolutionary processes. Multiple molecular epigenetic mechanisms exist, but methylation of DNA so far has dominated the Ecological Epigenetic literature. There are several molecular techniques used to screen methylation of DNA; here, we focus on the most common technique, methylation-sensitive-AFLP (MS-AFLP), which is used to identify genome-wide methylation patterns. We review studies that used MS-AFLP to address ecological questions, that describe which taxa have been investigated, and that identify general trends in the field. We then discuss, noting the general themes, four studies across taxa that demonstrate characteristics that increase the inferences that can be made from MS-AFLP data; we suggest that future MS-AFLP studies should incorporate these methods and techniques. We then review the short-comings of MS-AFLP and suggest alternative techniques that might address some of these limitations. Finally, we make specific suggestions for future research on MS-AFLP and identify questions that are most compelling and tractable in the short term.

  19. Development and validation of an LC-MS/MS method for the determination of SB-505124 in rat plasma: Application to pharmacokinetic study.

    PubMed

    Jiang, Jiayu; Zhang, Yuandong; Zhang, Quan; Li, Yanping; Gong, Tao; Zhang, Zhirong; Ding, Rui; Sun, Xun

    2016-01-05

    A sensitive, selective and rapid liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) method has been developed for the quantification of the novel transforming growth factor-β (TGF-β) inhibitor SB-505124 in rat plasma and then validated. Plasma samples were prepared by simple protein precipitation. Separation was performed on a Diamonsil ODS chromatography column using a mobile phase of acetonitrile and 0.1% (v/v) aqueous formic acid. SB-505124 and the internal standard doxorubicin were detected in the positive ion mode using multiple reaction monitoring of the transitions at m/z 336.2→320.1 and 544.2→397.2, respectively. Calibration curve was linear (r>0.9996) over a concentration range of 10-5000 ng/mL with the lower quantification limit of 10 ng/mL. Both intra- and inter-day precision were within 6.5% and trueness were not more than 3.1%. Extraction recovery and matrix effect were within acceptable limits. Stability tests showed that SB-505124 and the IS remained stable throughout the analytical procedure. The validated LC-MS/MS method was then used to analyze the pharmacokinetics of SB-505124 administered to rats intravenously (8 mg/kg) or orally (10 mg/kg). Oral bioavailability of SB-505124 was calculated as 76.4%, indicating the potential of SB-505124 as an orally administered drug.

  20. Characterization of Site-Specific N-Glycopeptide Isoforms of α-1-Acid Glycoprotein from an Interlaboratory Study Using LC-MS/MS.

    PubMed

    Lee, Ju Yeon; Lee, Hyun Kyoung; Park, Gun Wook; Hwang, Heeyoun; Jeong, Hoi Keun; Yun, Ki Na; Ji, Eun Sun; Kim, Kwang Hoe; Kim, Jun Seok; Kim, Jong Won; Yun, Sung Ho; Choi, Chi-Won; Kim, Seung Il; Lim, Jong-Sun; Jeong, Seul-Ki; Paik, Young-Ki; Lee, Soo-Youn; Park, Jisook; Kim, Su Yeon; Choi, Young-Jin; Kim, Yong-In; Seo, Jawon; Cho, Je-Yoel; Oh, Myoung Jin; Seo, Nari; An, Hyun Joo; Kim, Jin Young; Yoo, Jong Shin

    2016-12-02

    Glycoprotein conformations are complex and heterogeneous. Currently, site-specific characterization of glycopeptides is a challenge. We sought to establish an efficient method of N-glycoprotein characterization using mass spectrometry (MS). Using alpha-1-acid glycoprotein (AGP) as a model N-glycoprotein, we identified its tryptic N-glycopeptides and examined the data reproducibility in seven laboratories running different LC-MS/MS platforms. We used three test samples and one blind sample to evaluate instrument performance with entire sample preparation workflow. 165 site-specific N-glycopeptides representative of all N-glycosylation sites were identified from AGP 1 and AGP 2 isoforms. The glycopeptide fragmentations by collision-induced dissociation or higher-energy collisional dissociation (HCD) varied based on the MS analyzer. Orbitrap Elite identified the greatest number of AGP N-glycopeptides, followed by Triple TOF and Q-Exactive Plus. Reproducible generation of oxonium ions, glycan-cleaved glycopeptide fragment ions, and peptide backbone fragment ions was essential for successful identification. Laboratory proficiency affected the number of identified N-glycopeptides. The relative quantities of the 10 major N-glycopeptide isoforms of AGP detected in four laboratories were compared to assess reproducibility. Quantitative analysis showed that the coefficient of variation was <25% for all test samples. Our analytical protocol yielded identification and quantification of site-specific N-glycopeptide isoforms of AGP from control and disease plasma sample.

  1. Separation and fragmentation study of isocoproporphyrin derivatives by UHPLC-ESI-exact mass MS/MS and identification of a new isocoproporphyrin sulfonic acid metabolite.

    PubMed

    Benton, Christopher M; Lim, Chang Kee; Moniz, Caje; Baxter, Sinéad L; Jones, Donald J L

    2014-01-01

    Isocoproporphyrin and its derivatives are commonly used as biomarkers of porphyria cutanea tarda, heavy metal toxicity and hexachlorobenzene (HCB) intoxication in humans and animals. However, most are isobaric with other porphyrins and reference materials are unavailable commercially. The structural characterisation of these porphyrins is important but very little data is available. We report here the separation and characterisation of isocoproporphyrin, deethylisocoproporphyrin, hydroxyisocoproporphyrin and ketoisocoproporphyrin, isolated in the faeces of rats fed with a diet containing HCB, by ultra high performance liquid chromatography-exact mass tandem mass spectrometry (UHPLC-MS/MS). Furthermore, we report the identification and characterisation of a previously unreported porphyrin metabolite, isocoproporphyrin sulfonic acid isolated in the rat faeces. The measured mass-to-charge ratio (m/z) of the precursor ion was m/z 735.2338, corresponding to a molecular formula of C36H39N4O11S with an error of 0.3 ppm from the calculated m/z 735.2336. The MS/MS data was consistent with an isocoproporphyrin sulfonic acid structure, derived from dehydroisocoproporphyrinogen by sulfonation of the vinyl group. The metabolite was present in a greater abundance than other isocoproporphyrin derivatives and may be a more useful biomarker for HCB intoxication.

  2. A validated LC-MS/MS method for rapid determination of brazilin in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Deng, Zhipeng; Wang, Xin; Zhao, Huanxin; Cui, Shuxiang; Yao, Qingqiang; Bai, Hong

    2013-06-01

    Brazilin is a major homoisoflavonoid component isolated from the dried heartwood of traditional Chinese medicine Caesalpinia sappan L., which is a natural red pigment used for histological staining. Herein a sensitive, specific and rapid analytical LC-MS/MS method was established and validated for brazilin in rat plasma. After a simple step of protein precipitation using acetonitrile, plasma samples were analyzed using an LC-MS/MS system. Brazilin and the IS (protosappanin B) were separated on a Diamonsil C18 analytical column (150 × 4.6 mm, 5 µm) using a mixture of water and 10 mm ammonium acetate in methanol (20:80, v/v) as mobile phase at a flow rate of 0.6 mL/min. The method was sensitive with a lower limit of quantitation of 10.0 ng/mL, with good linearity (r(2) ≥ 0.99) over the linear range 10.0-5000 ng/mL. All the validation data, such as accuracy and precision, matrix effect, extraction recovery and stability tests were within the required limits. The assay method was successfully applied to evaluate the pharmacokinetics parameters of brazilin after an oral dose of 100 mg/kg brazilin in rats.

  3. Development of Chiral LC-MS Methods for small Molecules and Their Applications in the Analysis of Enantiomeric Composition and Pharmacokinetic Studies

    SciTech Connect

    Desai, Meera Jay

    2004-01-01

    used to simultaneously separate all 19 native amino acids enantiomerically in less than 20 minutes, making it suitable for complex biological analysis. The previously developed amino acid method was then used to enantiomerically separate theanine, a free amino acid found in tea leaves. Native theanine was found to have lower limits of detection and better sensitivity over derivatized theanine samples. The native theanine method was then used to determine the enantiomeric composition of six commercially available L-theanine products. Five out of the six samples were found to be a racemic mixture of both D- and L-theanine. Concern over the efficacy of these theanine products led to our final study evaluating the pharmacokinetics and pharmacodynamics of theanine in rats using LC-ESI/MS. Rats were administered D-, L, and QL-theanine both orally and intra-peritoneally. Oral administration data demonstrated that intestinal absorption of L-theanine was greater than that of D-theanine, while i.p. data showed equal plasma uptake of both isomers. This suggested a possible competitive binding effect with respect to gut absorption. Additionally, it was found that regardless of administration method, the presence of the other enantiomer always decreased overall theanine plasma concentration. This indicated that D- and L- theanine exhibit competitive binding with respect to urinary reabsorption as well. The large quantities of D-theanine detected in the urine suggested that D-themine was eliminated with minimal metabolism, while L-theanine was preferentially reabsorbed and metabolized to ethylamine. Clearly, the metabolic fate of racemic theanine and its individual enantiomers was quite different, placing into doubt the utility of the commercial theanine products.

  4. Determination of monoamine and amino acid neurotransmitters and their metabolites in rat brain samples by UFLC-MS/MS for the study of the sedative-hypnotic effects observed during treatment with S. chinensis.

    PubMed

    Wei, Binbin; Li, Qing; Fan, Ronghua; Su, Dan; Chen, Xiaohui; Jia, Ying; Bi, Kaishun

    2014-01-01

    Schisandra chinensis (Turcz.) Baill. has been used as a sedative and hypnotic agent in traditional Chinese medicine for centuries. The purpose of this study was to reveal the influence of insomnia on the levels of the neurotransmitters: glutamate (Glu), γ-aminobutyric acid (GABA), noradrenaline (NE), dopamine (DA), serotonin (5-HT) and their metabolites (5-HIAA, DOPAC and HVA), and to study the role of S. chinensis in the treatment of insomnia. To achieve this goal, an efficient, sensitive and selective method was developed and validated for the simultaneous determination of these five neurotransmitters and their metabolites in rat brain samples using ultra fast liquid chromatography/tandem mass spectrometry (UFLC-MS/MS). The analysis was performed on a Synergi Fusion-RP 80A ODS column (150mm×2.0mm, 4.0μm) using gradient elution, with the mobile phase consisting of acetonitrile and 0.05% formic acid in water. The method was validated using rat brain homogenate samples and showed a good linearity over a wide concentration range (r(2)>0.99) with a lower limit of quantification (LLOQ) at 4-16ngmL(-1). The intra and inter-day assay variability was less than 15% for all analytes. The results indicated that the condition of insomnia elevated GABA, NE, DA, DOPAC and HVA, and reduced 5-HT, 5-HIAA levels in rat brain. The oral administration of S. chinensis (7.5gkg(-1)day(-1), eight days) influenced insomnia by significantly increasing or reducing the levels of the neurotransmitters parameters mentioned above. These results suggested that S. chinensis could alter the levels of these brain neurotransmitters and their metabolites through its sedative-hypnotic effects.

  5. The translucent cadaver: a follow-up study to gauge the efficacy of implementing changes suggested by students.

    PubMed

    Kotzé, Sanet Henriët; Driescher, Natasha Darné; Mole, Calvin Gerald

    2013-01-01

    In a study conducted in 2011, the use of full body digital X-ray images (Lodox(®) Statscan(®)) and drawings were described for surface anatomy education during which suggestions were made by students on how to improve the method. Educational innovations should continuously be adjusted and improved to provide the best possible scenario for student learning. This study, therefore, reports on the efficacy of implementing some of these suggestions. Suggestions incorporated into the follow-up study included: (1) The inclusion of eight strategically placed labeled digital X-ray images to the dissection halls, (2) The placement of both labeled and unlabeled digital X-ray images online, (3) The inclusion of informal oral questions on surface anatomy during dissection, (4) The requirement of students to submit individual drawings in addition to group drawings into their portfolios, and (5) Integrating information on how to recognize anatomical structures on X-rays into gross anatomy lectures given prior to dissection. Students were requested to complete an anonymous questionnaire. The results of the drawings, tests and questionnaires were compared to the results from the 2011 cohort. During 2012, an increased usage of the digital X-rays and an increase in practical test marks in three out of the four modules (statistically significant only in the cardiovascular module) were reported. More students from the 2012 cohort believed the images enhanced their experience of learning surface anatomy and that its use should be continued in future. The suggested changes, therefore, had a positive effect on surface anatomy education.

  6. The in vivo and in vitro metabolism and the detectability in urine of 3',4'-methylenedioxy-alpha-pyrrolidinobutyrophenone (MDPBP), a new pyrrolidinophenone-type designer drug, studied by GC-MS and LC-MS(n.).

    PubMed

    Meyer, Markus R; Mauer, Sandra; Meyer, Golo M J; Dinger, Julia; Klein, Birgit; Westphal, Folker; Maurer, Hans H

    2014-01-01

    3',4'-Methylenedioxy-alpha-pyrrolidinobutyrophenone (MDPBP), a designer drug of the pyrrolidinophenone-type, was first seized in Germany in 2009. It was also identified in 'legal high' samples investigated in the UK. Therefore, the aim of the presented work was to identify its in vivo and in vitro phase I and II metabolites using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-ion trap mass spectrometry (LC-MS(n) ). Furthermore, detectability of MDPBP in rat and human urine using standard urine screening approaches (SUSA) by GC-MS and LC-MS(n) was studied. The metabolites were isolated either directly or after enzymatic cleavage of conjugates by solid-phase extraction (C18, HCX). The metabolites were then analyzed and structures proposed after GC-MS (phase I) and LC-MS(n) (phase II). Based on these identified metabolites, the following main metabolic steps could be proposed: demethylenation followed by methylation of one hydroxy group, aromatic and side chain hydroxylation, oxidation of the pyrrolidine ring to the corresponding lactam as well as ring opening to the corresponding carboxylic acid. Furthermore, in rat urine after a typical user's dose as well as in human urine, mainly the metabolites could be detected using the authors' SUSA by GC-MS and LC-MS(n) . Thus, it should be possible to monitor an application of MDPBP assuming similar toxicokinetics in humans. Finally, CYP2C19 and CYP2D6 could be identified as the isoenzymes mainly responsible for demethylenation.

  7. Study of vortex-assisted MSPD and LC-MS/MS using alternative solid supports for pharmaceutical extraction from marketed fish.

    PubMed

    Hertzog, Gabriel I; Soares, Karina L; Caldas, Sergiane S; Primel, Ednei G

    2015-06-01

    A procedure based on vortex-assisted matrix solid-phase dispersion (MSPD) for the extraction of 15 pharmaceuticals from fish samples with determination by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was validated. Florisil, C18, diatomaceous earth, chitin, and chitosan were evaluated as solid supports. Best results were obtained with 0.5 g of diatomaceous earth, 0.5 g of sodium sulfate, and 5 mL of methanol. Analytical recoveries ranged from 58 to 128 % with relative standard deviation (RSD) lower than 15 %. Limit of quantification (LOQ) values for the 15 compounds ranged from 5 to 1000 ng g(-1). The method under investigation has shown to be a simple and fast extraction tool with minimum instrumentation and low amount of reagent, resulting in method low cost. Besides, alternative materials, such as chitin and chitosan, which were applied to the dispersion step for the first time, were found to be interesting alternatives.

  8. Development and validation of a UHPLC-MS/MS bioanalytical method to quantify in plasma the analgesic candidate PT-31 following a preliminary pharmacokinetic study in rats.

    PubMed

    Bessegato, T C; Niehues, M; Buqui, G A; Lopes, N P; Pitta, I R; Galdino, S L; Dalla Costa, T

    2016-06-01

    A selective and sensitive UHPLC-MS/MS bioanalytical method to determine PT-31, an analgesic drug candidate, in rat plasma was developed and validated. Analyses were performed using a UHPLC-MS/MS system equipped with an electrospray ionization interface operating in the positive ionization mode using a C18 reversed-phase column with a mobile phase of water:acetonitrile (68:31, v/v) containing 0.1% acetic acid eluting in a gradient mode with a flow rate of 0.3 mL/min. Plasma samples were deproteinized with cold acetonitrile containing 0.01% TFA (1:2, v/v) and 50 μL of the supernatant were injected into the system. PT-31 and phenytoin (internal standard) retention times were roughly 1.0 and 1.5 min, respectively. Linear standard curves were plotted for the 0.01-10 µg/mL concentration range, with a coefficient of determination > 0.99. The method's precision was over 88%. Maximum intra- and inter-day relative standard deviations were 14.6% and 11.6%, respectively. Interfering substances were not detected in the chromatogram, indicating that the method was specific. PT-31 stability was assessed under different temperature and storage settings. The method was used to characterize PT-31 plasma pharmacokinetics following administration of 5 mg/kg i.v. to Wistar rats. Therefore, the method described is sensitive, linear, precise and specific enough to determine PT-31 in preclinical pharmacokinetic investigations. Copyright © 2015 John Wiley & Sons, Ltd.

  9. Fragmentation pathways and mechanisms of aromatic compounds in atmospheric pressure studied by GC-DMS and DMS-MS

    NASA Astrophysics Data System (ADS)

    Kendler, Shai; Lambertus, Gordon R.; Dunietz, Barry D.; Coy, Stephen L.; Nazarov, Erkinjon G.; Miller, Raanan A.; Sacks, Richard D.

    2007-06-01

    Differential mobility spectrometry (DMS) is a highly sensitive sensing technology capable of selecting and detecting ions based on the difference between ion mobility at high and low electric field. The combination of a micro-fabricated DMS with gas chromatography (GC) has allowed extensive investigation of the ion chemistry and collisionally induced dissociation (CID) of diaryl molecules on a millisecond timescale at temperatures up to 130 °C. DMS-pre-filtered time-of-flight mass spectrometry (DMS-MS) has been used to verify the chemical composition of the ion species resolved by GC-DMS. This work focuses on the fragmentation of diaryl compounds, including diphenyl methane (DPM) and bibenzyl (BB), using information from the DMS and DMS-MS spectra of a series of aromatic compounds. Density functional theory calculations have been used to investigate the geometry and the energy along the reaction coordinate for the loss of benzene from DPM·H+ and BB·H+ for comparison with GC-DMS and DMS-MS experimental results and with previously reported chemical ionization MS. DPM-H+ is observed to undergo field-induced fragmentation in the DMS to produce C7H7+(Bz+) and unobserved neutral benzene with a low energy barrier. In contrast, BB·H+ fragments to C8H9+ and benzene with a higher energy barrier. Calculated barriers and experimental results are in qualitative agreement. Depletion of the ionized fragments in favor of ion-neutral clusters was also observed at higher concentrations. It is suggested that CID in DMS can further enhance DMS analytical performance.

  10. A sensitive LC-MS/MS method for analysis of pericyazine in presence of 7-hydroxypericyazine and pericyazine sulphoxide in human plasma and its application to a comparative bioequivalence study in Chinese healthy volunteers.

    PubMed

    Cai, Hua Lin; Deng, Yang; Fang, Ping Fei; Cao, SiSi; Hou, Zhen Yan; Wu, Yan Qin; Chen, Xue Jiao; Yan, Miao; Zhang, BiKui

    2017-02-20

    A robust and highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of pericyazine in human plasma. The plasma sample was alkalized with sodium hydroxide solution and handled by liquid-liquid extraction with ethyl acetate after adding perphenazine as an internal standard (IS). The analytes were separated on an Ultimate™ AQ-C18 analytical column at 40°C, with a gradient elution consisting of A (aqueous phase: 5mM ammonium acetate buffer solution containing 0.1% formic acid) and B (organic phase: acetonitrile) at a flow rate of 0.350mL/min. The detection was conducted on an API 4000 tandem mass spectrometer coupled with electrospray ionization (ESI) source in positive ion mode. The multiple reaction monitoring (MRM) transitions, m/z 366.5>142.4 for pericyazine, m/z 382.5>142.4 for its 7-hydroxy and sulphoxide metabolites and m/z 404.3>171.3 for IS were chosen to achieve high selectivity in the simultaneous analyses. The method exhibited great improvement in sensitivity (LLOQ of 0.021ng/mL) and good linearity over the concentration range of 0.021-9.90ng/mL. The intra- and inter-day precision, accuracy, and stability results were within the acceptable limits and no matrix effect was observed. This method was successfully applied in a bioequivalence study to evaluate the pharmacokinetics in 20 healthy male Chinese volunteers. Additional exploratory analyses of 7-hydroxy and sulphoxide metabolites of pericyazine in the same samples suggest that the unchanged drug is predominant in the plasma and suitable for the bioequivalence comparison after a single oral administration of 10mg pericyazine.

  11. Hypnosis, suggestion, and suggestibility: an integrative model.

    PubMed

    Lynn, Steven Jay; Laurence, Jean-Roch; Kirsch, Irving

    2015-01-01

    This article elucidates an integrative model of hypnosis that integrates social, cultural, cognitive, and neurophysiological variables at play both in and out of hypnosis and considers their dynamic interaction as determinants of the multifaceted experience of hypnosis. The roles of these variables are examined in the induction and suggestion stages of hypnosis, including how they are related to the experience of involuntariness, one of the hallmarks of hypnosis. It is suggested that studies of the modification of hypnotic suggestibility; cognitive flexibility; response sets and expectancies; the default-mode network; and the search for the neurophysiological correlates of hypnosis, more broadly, in conjunction with research on social psychological variables, hold much promise to further understanding of hypnosis.

  12. Comparative study using MS and XRD of Fe80Al20 alloy produced by mechanical alloying

    NASA Astrophysics Data System (ADS)

    Hadef, F.; Otmani, A.; Grenèche, J. M.

    2013-08-01

    An X-ray diffraction and 57Fe Mössbauer effect study of mechanically alloyed Fe80Al20 is presented. X-ray measurements indicate that the disordered bcc α-Fe(Al) solid solution was formed after 2 h of milling, while the analysis of Mössbauer spectra suggested that total dissolution of aluminium is achieved after 10 h of milling. These differences can be attributed to: (i) rapid nanocrystallization of aluminium and/or (ii) small particles with small amounts of aluminium cannot be detected by the X-ray diffraction technique.

  13. Experimental study of MS2 and ΦX174 interactions with clays

    NASA Astrophysics Data System (ADS)

    Syngouna, V. I.; Chrysikopoulos, C.

    2009-12-01

    The transport and fate of viruses in subsurface formations are mainly governed by virus attachment onto the solid matrix and inactivation. Furthermore, virus attachment onto clay colloids is primarily controlled by electrostatic interactions between surfaces. Bacteriophage MS2 and ΦX174 were used as surrogates for human viruses in order to investigate the interaction between viruses and clay particles. The selected phyllosilicate clays were kaolinite and bentonite. Numerous reactor vessels were filled with 0.5 g of clay and 50 mL of sterile phosphate buffered at pH 7.0. A series of static and dynamic experiments for various bacteriophage concentrations were conducted at two different temperatures. Half of the reactor vessels were placed in a refrigerator at 4°C and the rest in a constant temperature room at 25°C. The dynamic batch experiments were performed with the reactor vessels attached to a small bench-top tube rotator. Appropriate adsorption isotherms were determined. Subsequently, the Derjaguin-Landau-Verwey-Overbeek theory was applied in order to determine the interaction energies between the bacteriophage and clay surfaces. The electric properties of the viral surfaces were also obtained at different pH values and ionic strength levels. The experimental results show that virus adsorption increases linearly with suspended virus concentration. The observed distribution coefficient (Kd) was higher for MS2 than ΦX174. Also, the observed Kd values were higher for the dynamic than static experiments, and increased with temperature. Moreover, the results indicate that the electrostatic interactions between viruses and the clays are significantly influenced by the solution’s ionic strength and pH. At pH 7, bacteriophage-clay energy barriers were higher for MS2 than ΦX174.

  14. North Atlantic weather regimes: A synoptic study of phase space. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Orrhede, Anna Karin

    1990-01-01

    In the phase space of weather, low frequency variability (LFV) of the atmosphere can be captured in a large scale subspace, where a trajectory connects consecutive large scale weather maps, thus revealing flow changes and recurrences. Using this approach, Vautard applied the trajectory speed minimization method (Vautard and Legras) to atmospheric data. From 37 winters of 700 mb geopotential height anomalies over the North Atlantic and the adjacent land masses, four persistent and recurrent weather patterns, interpreted as weather regimes, were discernable: a blocking regime, a zonal regime, a Greenland anticyclone regime, and an Atlantic regime. These regimes are studied further in terms of maintenance and transitions. A regime survey unveils preferences regarding event durations and precursors for the onset or break of an event. The transition frequencies between regimes vary, and together with the transition times, suggest the existence of easier transition routes. These matters are more systematically studied using complete synoptic map sequences from a number of events.

  15. The career aspirations of adolescents with eating disorders: an exploratory study and suggested links to adolescent self-concept development.

    PubMed

    Tsitsika, Artemis K; Tzavela, Eleni C; Apostolidou, Eftychia; Antonogeorgos, George; Sakou, Irine-Ikbale; Bakoula, Chryssa

    2014-01-01

    The health effects of eating disorders (EDs) in adolescence have been widely studied, but their impact on present adolescent psychosocial adjustment and development have been overseen. This study aimed to investigate the association between EDs and career aspirations in middle adolescence. The participants were 147 adolescents diagnosed with EDs. Participants reported on their future career aspirations, and these were coded according to the International Standard Classification of Education of 1997. Of the participants, 83 adolescents were followed up longitudinally, and their aspirations were reassessed and compared for stability across the two assessments. Moreover, participants' career aspirations were compared to those of healthy (non-ED) best-friend controls. Health-related and social-behavioral science careers were chosen significantly more by adolescents with an ED as compared to their non-ED counterparts. For adolescents with an ED, career choices were consistent across reassessments. These findings suggest that adolescents with an ED gravitate toward careers associated with their pathology, namely, both facets of their mind-body pathology. This finding may indicate restricted identity development for adolescents with an ED. Suggestions for treatments protocols to include identity exploration are discussed.

  16. Population Pharmacokinetic Study of Benznidazole in Pediatric Chagas Disease Suggests Efficacy despite Lower Plasma Concentrations than in Adults

    PubMed Central

    Altcheh, Jaime; Moscatelli, Guillermo; Mastrantonio, Guido; Moroni, Samanta; Giglio, Norberto; Marson, Maria Elena; Ballering, Griselda; Bisio, Margarita; Koren, Gideon; García-Bournissen, Facundo

    2014-01-01

    Introduction Chagas disease, caused by the parasite Trypanosoma cruzi, can lead to long term cardiac morbidity. Treatment of children with benznidazole is effective, but no pediatric pharmacokinetics data are available and clinical pharmacology information on the drug is scarce. Patients and Methods Prospective population pharmacokinetic (PK) cohort study in children 2–12 years old with Chagas disease treated with oral benznidazole 5–8 mg/kg/day BID for 60 days. (clinicaltrials.gov #NCT00699387). Results Forty children were enrolled in the study. Mean age was 7.3 years. A total of 117 samples were obtained from 38 patients for PK analysis. A one compartment model best fit the data. Weight-corrected clearance rate (CL/F) showed a good correlation with age, with younger patients having a significantly higher CL/F than older children and adults. Simulated median steady-state benznidazole concentrations, based on model parameters, were lower for children in our study than for adults and lowest for children under 7 years of age. Treatment was efficacious in the 37 patients who completed the treatment course, and well tolerated, with few, and mild, adverse drug reactions (ADRs). Discussion Observed benznidazole plasma concentrations in children were markedly lower than those previously reported in adults (treated with comparable mg/kg doses), possibly due to a higher CL/F in smaller children. These lower blood concentrations were nevertheless associated to a high therapeutic response in our cohort. Unlike adults, children have few adverse reactions to the drug, suggesting that there may be a direct correlation between drug concentrations and incidence of ADRs. Our results suggest that studies with lower doses in adults may be warranted. Trial Registration ClinicalTrails.gov NCT00699387 PMID:24853169

  17. Workshop report on atomic bomb dosimetry-residual radiation exposure: recent research and suggestions for future studies.

    PubMed

    Kerr, George D; Egbert, Stephen D; Al-Nabulsi, Isaf; Beck, Harold L; Cullings, Harry M; Endo, Satoru; Hoshi, Masaharu; Imanaka, Tetsuji; Kaul, Dean C; Maruyama, Satoshi; Reeves, Glen I; Ruehm, Werner; Sakaguchi, Aya; Simon, Steven L; Spriggs, Gregory D; Stram, Daniel O; Tonda, Tetsuji; Weiss, Joseph F; Weitz, Ronald L; Young, Robert W

    2013-08-01

    There is a need for accurate dosimetry for studies of health effects in the Japanese atomic bomb survivors because of the important role that these studies play in worldwide radiation protection standards. International experts have developed dosimetry systems, such as the Dosimetry System 2002 (DS02), which assess the initial radiation exposure to gamma rays and neutrons but only briefly consider the possibility of some minimal contribution to the total body dose by residual radiation exposure. In recognition of the need for an up-to-date review of the topic of residual radiation exposure in Hiroshima and Nagasaki, recently reported studies were reviewed at a technical session at the 57th Annual Meeting of the Health Physics Society in Sacramento, California, 22-26 July 2012. A one-day workshop was also held to provide time for detailed discussion of these newer studies and to evaluate their potential use in clarifying the residual radiation exposures to the atomic-bomb survivors at Hiroshima and Nagasaki. Suggestions for possible future studies are also included in this workshop report.

  18. Workshop Report on Atomic Bomb Dosimetry--Residual Radiation Exposure: Recent Research and Suggestions for Future Studies

    SciTech Connect

    2013-06-06

    There is a need for accurate dosimetry for studies of health effects in the Japanese atomic bomb survivors because of the important role that these studies play in worldwide radiation protection standards. International experts have developed dosimetry systems, such as the Dosimetry System 2002 (DS02), which assess the initial radiation exposure to gamma rays and neutrons but only briefly consider the possibility of some minimal contribution to the total body dose by residual radiation exposure. In recognition of the need for an up-to-date review of the topic of residual radiation exposure in Hiroshima and Nagasaki, recently reported studies were reviewed at a technical session at the 57th Annual Meeting of the Health Physics Society in Sacramento, California, 22-26 July 2012. A one-day workshop was also held to provide time for detailed discussion of these newer studies and to evaluate their potential use in clarifying the residual radiation exposures to the atomic-bomb survivors at Hiroshima and Nagasaki. Suggestions for possible future studies are also included in this workshop report.

  19. Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometric (LC/ESI-MS/MS) Study for the Identification and Characterization of In Vivo Metabolites of Cisplatin in Rat Kidney Cancer Tissues: Online Hydrogen/Deuterium (H/D) Exchange Study.

    PubMed

    Bandu, Raju; Ahn, Hyun Soo; Lee, Joon Won; Kim, Yong Woo; Choi, Seon Hee; Kim, Hak Jin; Kim, Kwang Pyo

    2015-01-01

    In vivo rat kidney tissue metabolites of an anticancer drug, cisplatin (cis-diamminedichloroplatinum [II]) (CP) which is used for the treatment of testicular, ovarian, bladder, cervical, esophageal, small cell lung, head and neck cancers, have been identified and characterized by using liquid chromatography positive ion electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) in combination with on line hydrogen/deuterium exchange (HDX) experiments. To identify in vivo metabolites, kidney tissues were collected after intravenous administration of CP to adult male Sprague-Dawley rats (n = 3 per group). The tissue samples were homogenized and extracted using newly optimized metabolite extraction procedure which involves liquid extraction with phosphate buffer containing ethyl acetate and protein precipitation with mixed solvents of methanol-water-chloroform followed by solid-phase clean-up procedure on Oasis HLB 3cc cartridges and then subjected to LC/ESI-HRMS analysis. A total of thirty one unknown in vivo metabolites have been identified and the structures of metabolites were elucidated using LC-MS/MS experiments combined with accurate mass measurements. Online HDX experiments have been used to further support the structural characterization of metabolites. The results showed that CP undergoes a series of ligand exchange biotransformation reactions with water and other nucleophiles like thio groups of methionine, cysteine, acetylcysteine, glutathione and thioether. This is the first research approach focused on the structure elucidation of biotransformation products of CP in rats, and the identification of metabolites provides essential information for further pharmacological and clinical studies of CP, and may also be useful to develop various effective new anticancer agents.

  20. How to gain insight into the polydispersity of tannins: a combined MS and LC study.

    PubMed

    Mouls, Laetitia; Hugouvieux, Virginie; Mazauric, Jean-Paul; Sommerer, Nicolas; Mazerolles, Gérard; Fulcrand, Hélène

    2014-12-15

    In the context of the potential health benefits of food polyphenols, the bioavailability of tannins (i.e. proanthocyanidins) is a major issue, which is strongly influenced by the polydispersity and the degree of polymerisation of tannins. The average degree of polymerisation (DP) of tannins is usually determined using depolymerisation methods, which do not provide any information about their polymer distribution. Moreover, it is still a challenge to characterise tannin fractions of high polydispersity and/or containing polymers of high molecular weights, due to the limit of detection of direct mass spectrometry (MS) analysis methods. In the present work, the polydispersity of several tannin fractions is investigated by two complementary methods: a MALDI-MS method and a semi-preparative sub-fractionation. Using a combination of these methods we are able to gain insight into the DP distributions of the fractions consisting of tannins of medium and high DP. Moreover combining analyses can be useful to assess and compare the DP distributions of most tannin fractions.

  1. Selenocysteine oxidation in glutathione peroxidase catalysis: an MS-supported quantum mechanics study.

    PubMed

    Orian, Laura; Mauri, Pierluigi; Roveri, Antonella; Toppo, Stefano; Benazzi, Louise; Bosello-Travain, Valentina; De Palma, Antonella; Maiorino, Matilde; Miotto, Giovanni; Zaccarin, Mattia; Polimeno, Antonino; Flohé, Leopold; Ursini, Fulvio

    2015-10-01

    Glutathione peroxidases (GPxs) are enzymes working with either selenium or sulfur catalysis. They adopted diverse functions ranging from detoxification of H(2)O(2) to redox signaling and differentiation. The relative stability of the selenoenzymes, however, remained enigmatic in view of the postulated involvement of a highly unstable selenenic acid form during catalysis. Nevertheless, density functional theory calculations obtained with a representative active site model verify the mechanistic concept of GPx catalysis and underscore its efficiency. However, they also allow that the selenenic acid, in the absence of the reducing substrate, reacts with a nitrogen in the active site. MS/MS analysis of oxidized rat GPx4 complies with the predicted structure, an 8-membered ring, in which selenium is bound as selenenylamide to the protein backbone. The intermediate can be re-integrated into the canonical GPx cycle by glutathione, whereas, under denaturing conditions, its selenium moiety undergoes β-cleavage with formation of a dehydro-alanine residue. The selenenylamide bypass prevents destruction of the redox center due to over-oxidation of the selenium or its elimination and likely allows fine-tuning of GPx activity or alternate substrate reactions for regulatory purposes.

  2. Degradation kinetics study of cabozantinib by a novel stability-indicating LC method and identification of its major degradation products by LC/TOF-MS and LC-MS/MS.

    PubMed

    Wu, Chunyong; Xu, Xue; Feng, Chao; Shi, Yuanyuan; Liu, Wenyuan; Zhu, Xiaoyun; Zhang, Junying

    2014-09-01

    The chemical stability of cabozantinib (CBZ) was investigated using a novel stability-indicating LC method. Forced degradation of CBZ was carried out under acidic, basic, thermal, oxidative and photolytic stress conditions. Hydrolysis and oxidation were the primary pathways for this compound and three major unknown degradation products were characterized by LC/TOF-MS and LC-MS/MS. The major oxidative degradation product was isolated by preparative LC and identified by UV, HRMS and NMR techniques to be N-{4-[(N-oxide-6,7-dimethoxyquinolin-4-yl)oxy]phenyl}-N'-(4-fluorophenyl)-cyclopropane-1,1-dicarboxamide. The developed method was validated as per ICH guidelines and then successfully applied to investigate the degradation kinetics of CBZ. Degradation of CBZ followed first-order kinetics under all experimental conditions. A V-shaped pH-rate profile over the pH range 2-10 was observed with maximum stability at pH 6. The effect of temperature on the rate of CBZ degradation was characterized using the Arrhenius equation. The activation energy for hydrolysis was 57.31kJmol(-1) in alkaline solution.

  3. Fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry interface (MAGIC-LC/MS)

    SciTech Connect

    Browner, R.F.

    1990-10-01

    Accomplishments on the fundamental studies with a monodisperse aerosol-based liquid chromatography/mass spectrometry (LC/MS) interface during the period 1 December 1989 to 30 November 1990 are summarized. In order to determine the influence of temperature on the vaporization and decomposition properties of molecules, test have been carried out on both thermally stable and thermally labile molecules. The test compounds used were a series of polynuclear aromatic (PAH) compounds covering a wide range of molecular weights from two-ring naphthalene to twelve-ring perylene. The less thermally stable species examined were aldicarb, a highly thermally labile pesticide, and cholesterol, which readily loses water when subjected to high temperatures. A new, externally heated probe, which can be raised to temperatures as high as 500{degree}C was also used. Matrix loading effects for a range of surface active and non-surface active compounds in three different matrices: glycerol, 3-nitrobenzyl alcohol, and thioglycerol for fast atom bombardment (FAB) particle beam LC/MS have been studied. The time dependence of FAB spectra generation in the particle beam system has been examined and contrasted with ion generation in normal probe FAB work. Future FAB LC/MS research is outlined. 3 refs. (BM)

  4. Study of Gene Trafficking between Acanthamoeba and Giant Viruses Suggests an Undiscovered Family of Amoeba-Infecting Viruses

    PubMed Central

    Maumus, Florian; Blanc, Guillaume

    2016-01-01

    The nucleocytoplasmic large DNA viruses (NCLDV) are a group of extremely complex double-stranded DNA viruses, which are major parasites of a variety of eukaryotes. Recent studies showed that certain unicellular eukaryotes contain fragments of NCLDV DNA integrated in their genome, when surprisingly many of these organisms were not previously shown to be infected by NCLDVs. These findings prompted us to search the genome of Acanthamoeba castellanii strain Neff (Neff), one of the most prolific hosts in the discovery of giant NCLDVs, for possible DNA inserts of viral origin. We report the identification of 267 markers of lateral gene transfer with viruses, approximately half of which are clustered in Neff genome regions of viral origins, transcriptionally inactive or exhibit nucleotide-composition signatures suggestive of a foreign origin. The integrated viral genes had diverse origin among relatives of viruses that infect Neff, including Mollivirus, Pandoravirus, Marseillevirus, Pithovirus, and Mimivirus. However, phylogenetic analysis suggests the existence of a yet-undiscovered family of amoeba-infecting NCLDV in addition to the five already characterized. The active transcription of some apparently anciently integrated virus-like genes suggests that some viral genes might have been domesticated during the amoeba evolution. These insights confirm that genomic insertion of NCLDV DNA is a common theme in eukaryotes. This gene flow contributed fertilizing the eukaryotic gene repertoire and participated in the occurrence of orphan genes, a long standing issue in genomics. Search for viral inserts in eukaryotic genomes followed by environmental screening of the original viruses should be used to isolate radically new NCLDVs. PMID:27811174

  5. Study of Gene Trafficking between Acanthamoeba and Giant Viruses Suggests an Undiscovered Family of Amoeba-Infecting Viruses.

    PubMed

    Maumus, Florian; Blanc, Guillaume

    2016-12-14

    The nucleocytoplasmic large DNA viruses (NCLDV) are a group of extremely complex double-stranded DNA viruses, which are major parasites of a variety of eukaryotes. Recent studies showed that certain unicellular eukaryotes contain fragments of NCLDV DNA integrated in their genome, when surprisingly many of these organisms were not previously shown to be infected by NCLDVs. These findings prompted us to search the genome of Acanthamoeba castellanii strain Neff (Neff), one of the most prolific hosts in the discovery of giant NCLDVs, for possible DNA inserts of viral origin. We report the identification of 267 markers of lateral gene transfer with viruses, approximately half of which are clustered in Neff genome regions of viral origins, transcriptionally inactive or exhibit nucleotide-composition signatures suggestive of a foreign origin. The integrated viral genes had diverse origin among relatives of viruses that infect Neff, including Mollivirus, Pandoravirus, Marseillevirus, Pithovirus, and Mimivirus However, phylogenetic analysis suggests the existence of a yet-undiscovered family of amoeba-infecting NCLDV in addition to the five already characterized. The active transcription of some apparently anciently integrated virus-like genes suggests that some viral genes might have been domesticated during the amoeba evolution. These insights confirm that genomic insertion of NCLDV DNA is a common theme in eukaryotes. This gene flow contributed fertilizing the eukaryotic gene repertoire and participated in the occurrence of orphan genes, a long standing issue in genomics. Search for viral inserts in eukaryotic genomes followed by environmental screening of the original viruses should be used to isolate radically new NCLDVs.

  6. MS Detectors

    SciTech Connect

    Koppenaal, David W.; Barinaga, Charles J.; Denton, M Bonner B.; Sperline, Roger P.; Hieftje, Gary M.; Schilling, G. D.; Andrade, Francisco J.; Barnes IV., James H.

    2005-11-01

    Good eyesight is often taken for granted, a situation that everyone appreciates once vision begins to fade with age. New eyeglasses or contact lenses are traditional ways to improve vision, but recent new technology, i.e. LASIK laser eye surgery, provides a new and exciting means for marked vision restoration and improvement. In mass spectrometry, detectors are the 'eyes' of the MS instrument. These 'eyes' have also been taken for granted. New detectors and new technologies are likewise needed to correct, improve, and extend ion detection and hence, our 'chemical vision'. The purpose of this report is to review and assess current MS detector technology and to provide a glimpse towards future detector technologies. It is hoped that the report will also serve to motivate interest, prompt ideas, and inspire new visions for ion detection research.

  7. A sensitive LC-MS/MS method for simultaneous determination of six flavonoids in rat plasma: application to a pharmacokinetic study of total flavonoids from mulberry leaves.

    PubMed

    He, Jun; Feng, Ying; Ouyang, Hui-Zi; Yu, Bin; Chang, Yan-Xu; Pan, Gui-Xiang; Dong, Gai-Ying; Wang, Tao; Gao, Xiu-Mei

    2013-10-01

    A simple and sensitive LC-MS/MS method has been developed and validated for the determination of rutin, isoquercitrin, astragalin, quercetin, kaempferol and isorhamnetin in rat plasma using naringin as the internal standard (IS). The plasma samples were pretreated and extracted by liquid-liquid extraction. Chromatographic separation was accomplished on a C18 column with a 10 min gradient elution using acetonitrile and 0.1% formic acid aqueous solution as mobile phase at a flow rate of 0.3 mL min(-1). A tandem mass spectrometric detection was conducted using multiple reaction monitoring (MRM) via an electrospray ionization (ESI) source and operating in the negative ionization mode. The lower limit of quantitation (LLOQ) of each analyte was lower than 1 ng mL(-1). Intra-day and inter-day precisions were less than 11.9%. The relative errors of accuracy were in the range of -9.2% to 6.1%. The mean recoveries of flavonoids and IS were higher than 53.8%. The proposed method was further applied to investigate the pharmacokinetics of all analytes after a single oral administration of total flavonoids from mulberry leaves to rats.

  8. Simultaneous determination of five mercapturic acid derived from volatile organic compounds in human urine by LC-MS/MS and its application to relationship study.

    PubMed

    Zhang, Xiaotao; Xiong, Wei; Shi, Longkai; Hou, Hongwei; Hu, Qingyuan

    2014-09-15

    Acrylonitrile, acrolein, 1,3-butadiene, benzene, and crotonaldehyde are hazard volatile organic compounds in tobacco smoke, which can be metabolized to mercapturic acids (MAs) excreted in urine. MAs are can be regarded as important and specific biomarkers to evaluate exposure to those carcinogenic volatile organic compounds. A simultaneous determination of N-acetyl-S-2-cyanoethyl-cysteine (CEMA), 3-hydroxypropyl)-L-cysteine (3-HPMA), N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA), N-acetyl-S-(phenyl)-L-cysteine (SPMA) and 3-hydroxy-1-methylpropylmercapturic acid (HMPMA) derived from five volatile organic compounds by column-switching LC-MS/MS has been described. MAs were concentrated and cleaned up by an online reusable pre-column packed with restricted access material. The intra- and inter-day precisions of the method ranged from 0.7% to 15.2%. The LODs was 0.013-0.053 ng/mL. The recovery of the whole analytical procedure ranged from 79.3% to 116%. After validation, this method was successfully applied to urine samples from smokers (n=246) and nonsmokers (n=58). The results showed MAs in urine from smokers were significantly higher than that in nonsmoker except for SPMA. Urinary CEMA significantly correlated with 3-HPMA (r=0.763, P<0.0001) and HMPMA (r=0.910, P<0.0001). CEMA, 3-HPMA and HMPMA are potential biomarkers to distinguish the differences between smokers and nonsmokers.

  9. Single-laboratory validation study of rapid analysis method for multi-class veterinary drugs in milk, fish and shellfish by LC-MS/MS.

    PubMed

    Nakajima, Takayuki; Nagano, Chieko; Kanda, Maki; Hayashi, Hiroshi; Hashimoto, Tsuneo; Kanai, Setsuko; Matsushima, Yoko; Tateishi, Yukinari; Sasamoto, Takeo; Takano, Ichiro

    2013-01-01

    A method of rapid analysis of multi-class residual veterinary drugs in milk, fish and shellfish was validated in accordance with Japanese guidelines for the validation of analytical methods for residual agricultural chemicals in food. Using LC-MS/MS, 43 multi-class veterinary drugs, including sulfonamides, quinolones, coccidiostats and antiparasites, could be analyzed in one injection. Analytes were extracted from samples with two kinds of solvent, acetonitrile containing 1 vol% formic acid and anhydrous acetonitrile, and salted out with 4.0 g of magnesium sulfate, 1.5 g of trisodium citrate and 2.0 g of sodium chloride. This method was assessed by performing recovery tests in retail milk and 4 kinds of fresh cultured fish and shellfish (salmon, tiger shrimp, red sea bream and bastard halibut) spiked with the 43 target analytes at the levels of 10 and 100 μg/kg. Using this method, 40 out of 43 drugs satisfied the guideline criteria in milk, 37 drugs in salmon, 42 drugs in tiger shrimp, 41 drugs in red sea bream and 39 drugs in bastard halibut.

  10. Development and validation of an LC-MS/MS method for the determination of mesalazine in beagle dog plasma and its application to a pharmacokinetic study.

    PubMed

    Qin, Juan; Di, Xin; Wang, Xin; Liu, Youping

    2015-02-01

    A simple, specific and sensitive LC-MS/MS method was developed and validated for the determination of mesalazine in beagle dog plasma. The plasma samples were prepared by protein precipitation, then the separation of the analyte was achieved on a Waters Spherisorb C6 column (150 × 4.6 mm, 5 µm) with a mobile phase consisting of 0.2% formic acid in water-methanol (20:80, v/v). The flow rate was set at 1.0 mL/min with a split ratio of 3:2. Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode. Quantitation was performed using selected reaction monitoring of precursor-product ion transitions at m/z 154 → m/z 108 for mesalazine and m/z 285 → m/z 193 for diazepam (internal standard). The linear calibration curve of mesalazine was obtained over the concentration range 50-30,000 ng/mL. The matrix effect of mesalazine was within ±9.8%. The intra- and inter-day precisions were <7.9% and the accuracy (relative error) was within ±3.5%. The validated method was successfully applied to investigate the pharmacokinetics of mesalazine in healthy beagle dogs after rectal administration of mesalazine suppository.

  11. Simultaneous Determination and Pharmacokinetic Study of Six Components in Rat Plasma by HPLC-MS/MS after Oral Administration of Acanthopanax sessiliflorus Fruit Extract

    PubMed Central

    Du, Peng; Lei, Mingdao; Liu, Yu; Yang, Shilin

    2016-01-01

    A specific and reliable HPLC-MS/MS method was developed and validated for the simultaneous determination of protocatechuic acid (PCA), scopolin, (−)-pinoresinol-4,4′-di-O-β-d-glucopyranoside (PDG), acanthoside D, acanthoside B and hyperin in rat plasma for the first time. The analytes were separated on a C18 column (50 × 2.1 mm, 1.8 µm) and a triple-quadrupole mass spectrometer equipped with an electrospray ionization (ESI) source was used for detection. The rat plasma sample was prepared using the protein precipitation procedure. The calibration curves were linear over a concentration range of 1.2–1200.0 ng/mL for PCA, 0.96–960.0 ng/mL for scopolin, 1.12–1120.0 ng/mL for PDG, 1.32–1320.0 ng/mL for acanthoside D, 0.99–990.0 ng/mL for acanthoside B and 1.01–1010.0 ng/mL for hyperin. The intra-day and inter-day precision was less than 11.4% and the relative error (RE) was all within ±15%. The validated method was successfully applied to assess the pharmacokinetics characteristics after the extracts of Acanthopanax sessiliflorus fruits were orally administered to the Sprague-Dawley rat. PMID:28036026

  12. [Study of multi-residue method for determining pesticide residues in processed foods manufactured from agricultural products by LC-MS/MS].

    PubMed

    Fukui, Naoki; Takatori, Satoshi; Kitagawa, Yoko; Okihashi, Masahiro; Kajimura, Keiji; Obana, Hirotaka

    2013-01-01

    A rapid multi-residue method for determination of pesticide residues in processed foods manufactured from agricultural products was examined. Five mL water was added to 5 g sample in a polypropylene tube, and the tube was left to stand at room temperature for 30 min. Then, 20 mL acetonitrile was added to the sample. The mixture was homogenized in a high-speed homogenizer, followed by salting out with 1 g NaCl and 4 g anhydrous MgSO4. After centrifugation, the organic layer was purified on a graphitized carbon/PSA cartridge column. After removal of the solvent, the extract was resolved in methanol-water and analyzed with LC-MS/MS. The recoveries of 93 pesticides fortified into 5 kinds of processed foods [Chinese cabbage kimchi, marmalade, raisin, umeboshi (pickled plum) and worcester sauce] were examined at the concentrations of 0.02 and 0.1 μg/g (n=5). The recoveries of 61 pesticides in all foods were 70-120% with relative standard deviation below 20% at both concentrations. Seventy-four processed foods obtained from markets in Japan were examined with this method. Pesticide residues over the maximum residue limit (0.01 μg/g) were detected in 2 processed foods.

  13. Quantum-chemical, NMR, FT IR, and ESI MS studies of complexes of colchicine with Zn(II).

    PubMed

    Jankowski, Wojciech; Kurek, Joanna; Barczyński, Piotr; Hoffmann, Marcin

    2017-04-01

    Colchicine is a tropolone alkaloid from Colchicinum autumnale. It shows antifibrotic, antimitotic, and anti-inflammatory activities, and is used to treat gout and Mediterranean fever. In this work, complexes of colchicine with zinc(II) nitrate were synthesized and investigated using DFT, (1)H and (13)C NMR, FT IR, and ESI MS. The counterpoise-corrected and uncorrected interaction energies of these complexes were calculated. We also calculated their (1)H, (13)C NMR, and IR spectra and compared them with the corresponding experimentally obtained data. According to the ESI MS mass spectra, colchicine forms stable complexes with zinc(II) nitrate that have various stoichiometries: 2:1, 1:1:1, and 2:1:1 with respect to colchichine, Zn(II), and nitrate ion. All of the complexes were investigated using the quantum theory of atoms in molecules (QTAIM). The calculated and the measured spectra showed differences before and after the complexation process. Calculated electron densities and bond critical points indicated the presence of bonds between the ligands and the central cation in the investigated complexes that satisfied the quantum theory of atoms in molecules. Graphical Abstract DFT, NMR, FT IR, ESI MS, QTAIM and puckering studies of complexes of colchicine with Zn(II).

  14. GC-MS and GC-IRD studies on dimethoxyphenethylamines (DMPEA): regioisomers related to 2,5-DMPEA.

    PubMed

    Maher, Hadir M; Awad, Tamer; DeRuiter, Jack; Clark, C Randall

    2012-01-01

    A series of regioisomeric dimethoxyphenethylamines have a mass spectra essentially equivalent to the drug substance 2,5-dimethoxyphenethylamine (2,5-DMPEA). These substances have a molecular weight of 181, and major fragment ions in their electron ionization mass spectra at m/z 151/152. The trifluoroacetyl, pentafluoropropionyl, and heptafluorobutryl derivatives of these primary amines were prepared and evaluated by gas chromatography with mass spectrometry detection (GC-MS). The mass spectra for these derivatives do not show unique fragment ions to allow the specific identification of a particular isomer. Thus, GC-MS does not provide for the confirmation of identity of any one of the six isomers to the exclusion of the other five compounds. However, GC-MS does divide the compounds into two groups depending on the mass of the base peak. GC with infrared detection provides direct confirmatory data for the identification of 2,5-DMPEA from the other regioisomers involved in the study. Perfluoroacylated derivatives of the six regioisomeric dimethoxyphenethylamines were successfully resolved via capillary GC on a non-polar stationary phase consisting of 50% phenyl and 50% methyl polysiloxane (Rxi-50).

  15. A GC-MS-based metabolomics study on the tubers of commercial potato cultivars upon storage.

    PubMed

    Uri, Csilla; Juhász, Zsófia; Polgár, Zsolt; Bánfalvi, Zsófia

    2014-09-15

    Using gas chromatography-mass spectrometry (GC-MS) as a system for the detection of amino acids, organic acids, sugars, sugar alcohols, and fatty acids, we characterised six commercial potato cultivars (Hópehely, Katica, Lorett, Somogyi kifli, Vénusz Gold, and White Lady) with different pedigrees, starch contents, cooking types, and dormancy periods, in five developmental stages from harvest to sprouting. The tubers were stored at 20-22°C in the dark. The metabolite data were subjected to principal component analysis. No correlation between metabolite contents of freshly harvested tubers and starch content or cooking type of the cultivars was detected. The storage decreased the fructose and sucrose and increased the proline concentrations of tubers. Irrespective of the length of dormancy a substantial difference in metabolite composition at each time point upon storage was detected in each cultivar except Somogyi kifli, the only cultivar amongst those tested with a pure Solanum tuberosum origin and A cooking type.

  16. Metabolic studies of four soy isoflavones in rats by HPLC-HR-MS.

    PubMed

    Li, Ying-Fei; Ren, Qiang; Jin, Ying; Wu, Cai-Sheng; Wang, Cai-Hong; Jia, Zhi-Xin; Zhang, Jin-Lan

    2014-01-01

    In this paper, the metabolites of four soy isoflavones, daidzein, daidzin, genistein, and genistin, on perfused rat intestine-liver model were investigated by high-performance liquid chromatography coupled with high-resolution mass spectrometer/tandem mass spectrometer. Totally 16 metabolites were detected and identified based on accurate mass, fragmentation patterns, and multiple-stage mass data (MS(n)). The metabolic site of dadzein-7-methyl ether (D-7-M) was further confirmed by nuclear magnetic resonance. Methylation, glucuronide conjugation, and sulfate conjugation were the primary metabolic processes. Among them, six metabolites, daidzin-4',7-diglucoside, genistein-4'-glucoside, D-7-M, dadzein-4',7-dimethyl ether, genistein-4'-methyl ether, and genistein-7-methyl ether were detected in rats for the first time and not reported in humans. The metabolic pathways of daidzein, daidzin genistein, and genistin in rats were postulated. The biological effects of these metabolites are worthy of further investigation.

  17. Studies on the content of heavy metals in Aries River using ICP-MS

    SciTech Connect

    Voica, Cezara Kovacs, Melinda Feher, Ioana

    2013-11-13

    Among the industrial branches, the mining industry has always been an important source of environmental pollution, both aesthetically and chemically. Through this paper results of ICP-MS characterization of Aries River Basin are reported. Mining activities from this area has resulted in contamination of environment and its surrounding biota. This is clearly evidenced in analyzed water samples, especially from Baia de Aries site where increased amount of trace elements as Cr, Zn, As, Se, Cd, Pb and U were founded. Also in this site greater amount of rare earth elements was evidenced also. Through monitoring of Aries River from other non-mining area it was observed that the quantitative content of heavy metals was below the maximum permissible levels which made us to conclude that the water table wasn't seriously affected (which possibly might be attributed to the cessation of mining activities in this area from a few years ago)

  18. NMR- and GC/MS-based metabolomics of sulfur mustard exposed individuals: a pilot study.

    PubMed

    Nobakht, B Fatemeh; Aliannejad, Rasoul; Rezaei-Tavirani, Mostafa; Arefi Oskouie, Afsaneh; Naseri, Mohammad Taghi; Parastar, Hadi; Aliakbarzadeh, Ghazaleh; Fathi, Fariba; Taheri, Salman

    2016-09-01

    Sulfur mustard (SM) is a potent alkylating agent and its effects on cells and tissues are varied and complex. Due to limitations in the diagnostics of sulfur mustard exposed individuals (SMEIs) by noninvasive approaches, there is a great necessity to develop novel techniques and biomarkers for this condition. We present here the first nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC/MS) metabolic profiling of serum from and healthy controls to identify novel biomarkers in blood serum for better diagnostics. Of note, SMEIs were exposed to SM 30 years ago and that differences between two groups could still be found. Pathways in which differences between SMEIs and healthy controls are observed are related to lipid metabolism, ketogenesis, tricarboxylic acid (TCA) cycle and amino acid metabolism.

  19. Qualitative and quantitative studies of chemical composition of sandarac resin by GC-MS.

    PubMed

    Kononenko, I; de Viguerie, L; Rochut, S; Walter, Ph

    2017-01-01

    The chemical composition of sandarac resin was investigated qualitatively and quantitatively by gas chromatography-mass spectrometry (GC-MS). Six compounds with labdane and pimarane skeletons were identified in the resin. The obtained mass spectra were interpreted and the mass spectrometric behaviour of these diterpenoids under EI conditions was described. Quantitative analysis by the method of internal standard revealed that identified diterpenoids represent only 10-30% of the analysed sample. The sandarac resin from different suppliers was analysed (from Kremer, Okhra, Color Rare, La Marchande de Couleurs, L'Atelier Montessori, Hevea). The analysis of different lumps of resins showed that the chemical composition differs from one lump to another, varying mainly in the relative distributions of the components.

  20. REE in skarn systems: A LA-ICP-MS study of garnets from the Crown Jewel gold deposit

    NASA Astrophysics Data System (ADS)

    Gaspar, Miguel; Knaack, Charles; Meinert, Lawrence D.; Moretti, Roberto

    2008-01-01

    Metamorphic and magmatic garnets are known to fractionate REE, with generally HREE-enriched patterns, and high Lu/Hf and Sm/Nd ratios, making them very useful as geochemical tracers and in geochronological studies. However, these garnets are typically Al-rich (pyrope, almandine, spessartine, and grossular) and little is known about garnets with a more andraditic (Fe 3+) composition, as frequently found in skarn systems. This paper presents LA-ICP-MS data for garnets from the Crown Jewel Au-skarn deposit (USA), discusses the factors controlling incorporation of REE into garnets, and strengthens the potential of garnet REE geochemistry as a tool to help understand the evolution of metasomatic fluids. Garnets from the Crown Jewel deposit range from Adr 30Grs 70 to almost pure andradite (Adr >99). Fe-rich garnets (Adr >90) are isotropic, whereas Al-rich garnets deviate from cubic symmetry and are anisotropic, often showing sectorial dodecahedral twinning. All garnets are extremely LILE-depleted, Ta, Hf, and Th and reveal a positive correlation of ΣREE 3+ with Al content. The Al-rich garnets are relatively enriched in Y, Zr, and Sc and show "typical" HREE-enriched and LREE-depleted patterns with small Eu anomalies. Fe-rich garnets (Adr >90) have much lower ΣREE and exhibit LREE-enriched and HREE-depleted patterns, with a strong positive Eu anomaly. Incorporation of REE into garnet is in part controlled by its crystal chemistry, with REE 3+ following a coupled, YAG-type substitution mechanism ([X]-1VIII[REE]+1VIII[Si]-1IV[Z]+1IV), whereas Eu 2+ substitutes for X 2+ cations. Thermodynamic data (e.g., Hmixing) in grossular-andradite mixtures suggest preferential incorporation of HREE in grossular and LREE in more andraditic compositions. Variations in textural and optical features and in garnet geochemistry are largely controlled by external factors, such as fluid composition, W/ R ratios, mineral growth kinetics, and metasomatism dynamics, suggesting an overall system

  1. Measurements of hydrogen sulfide (H2S) using PTR-MS: calibration, humidity dependence, inter-comparison and results from field studies in an oil and gas production region

    NASA Astrophysics Data System (ADS)

    Li, R.; Warneke, C.; Graus, M.; Field, R.; Geiger, F.; Veres, P. R.; Soltis, J.; Li, S.-M.; Murphy, S. M.; Sweeney, C.; Pétron, G.; Roberts, J. M.; de Gouw, J.

    2014-06-01

    Natural gas production is associated with emissions of several trace gases, some of them classified as air toxics. While volatile organic compounds (VOCs) have received much attention, hydrogen sulfide (H2S) can also be of concern due to the known health impacts of exposure to this hazardous air pollutant. Here, we present quantitative, fast time-response measurements of H2S using Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS) instruments. An Ultra-Light-Weight PTR-MS (ULW-PTR-MS) in a mobile laboratory was operated for measurements of VOCs and H2S in a gas and oil field during the Uintah Basin Winter Ozone Study (UBWOS) 2012 campaign. Measurements of VOCs and H2S by a PTR-MS were also made at the Horse Pool ground site in the Uintah Basin during UBWOS 2013. The H2S measurement by PTR-MS is strongly humidity dependent because the proton affinity of H2S is only slightly higher than that of water. The H2S sensitivity of PTR-MS ranged between 0.6-1.4 ncps ppbv-1 (normalized counts per second/parts per billion by volume) during UBWOS 2013. We compare the humidity dependence determined in the laboratory with in-field calibrations and determine the H2S mixing ratios for the mobile and ground measurements. The PTR-MS measurements at Horse Pool are evaluated by comparison with simultaneous H2S measurements using a PTR Time-of-Flight MS (PTR-ToF-MS) and a Picarro cavity ring down spectroscopy (CRDS) instrument for H2S/CH4. On average 0.6 ± 0.3 ppbv H2S was present at Horse Pool during UBWOS 2013. The correlation between H2S and methane enhancements suggests that the source of H2S is associated with oil and gas extraction in the basin. Significant H2S mixing ratios of up to 9 ppmv downwind of storage tanks were observed during the mobile measurements. This study suggests that H2S emissions associated with oil and gas production can lead to short-term high levels close to point sources, and elevated background levels away from those sources. In addition, our work has

  2. Measurements of hydrogen sulfide (H2S) using PTR-MS: calibration, humidity dependence, inter-comparison and results from field studies in an oil and gas production region

    NASA Astrophysics Data System (ADS)

    Li, R.; Warneke, C.; Graus, M.; Field, R.; Geiger, F.; Veres, P. R.; Soltis, J.; Li, S.-M.; Murphy, S. M.; Sweeney, C.; Pétron, G.; Roberts, J. M.; de Gouw, J.

    2014-10-01

    Natural gas production is associated with emissions of several trace gases, some of them classified as air toxics. While volatile organic compounds (VOCs) have received much attention, hydrogen sulfide (H2S) can also be of concern due to the known health impacts of exposure to this hazardous air pollutant. Here, we present quantitative, fast time-response measurements of H2S using proton-transfer-reaction mass-spectrometry (PTR-MS) instruments. An ultra-light-weight PTR-MS (ULW-PTR-MS) in a mobile laboratory was operated for measurements of VOCs and H2S in a gas and oil field during the Uintah Basin Winter Ozone Study (UBWOS) 2012 campaign. Measurements of VOCs and H2S by a PTR-MS were also made at the Horse Pool ground site in the Uintah Basin during UBWOS 2013. The H2S measurement by PTR-MS is strongly humidity dependent because the proton affinity of H2S is only slightly higher than that of water. The H2S sensitivity of PTR-MS ranged between 0.6-1.4 ncps ppbv-1 during UBWOS 2013. We compare the humidity dependence determined in the laboratory with in-field calibrations and determine the H2S mixing ratios for the mobile and ground measurements. The PTR-MS measurements at Horse Pool are evaluated by comparison with simultaneous H2S measurements using a PTR time-of-flight MS (PTR-ToF-MS) and a Picarro cavity ring down spectroscopy (CRDS) instrument for H2S / CH4. On average 0.6 ± 0.3 ppbv H2S was present at Horse Pool during UBWOS 2013. The correlation between H2S and methane enhancements suggests that the source of H2S is associated with oil and gas extraction in the basin. Significant H2S mixing ratios of up to 9 ppmv downwind of storage tanks were observed during the mobile measurements. This study suggests that H2S emissions associated with oil and gas production can lead to short-term high levels close to point sources, and elevated background levels away from those sources. In addition, our work has demonstrated that PTR-MS can make reliable measurements of

  3. Development and validation of an UFLC-MS/MS method for enantioselectivity determination of d,l-thero-methylphenidate, d,l-thero-ethylphenidate and d,l-thero-ritalinic acid in rat plasma and its application to pharmacokinetic study.

    PubMed

    Zhang, Chenghao; Luo, Huafei; Wu, Yubo; Zhang, Junyun; Zhang, Furong; Lin, Guobei; Wang, Hao

    2016-02-01

    A chiral UFLC-MS/MS method was established and validated for quantifying d-threo-methylphenidate (d-threo-MPH), l-threo-methylphenidate (l-threo-MPH), d-threo-ethylphenidate (d-threo-EPH), l-threo-ethylphenidate (l-threo-EPH) and d,l-threo-ritalinic acid (d,l-threo-RA) in rat plasma over the linearity range of 1-500ng/mL. Chiral separation was performed on an Astec Chirobiotic V2 column (5μm, 250×2.1mm) with isocratic elution using methanol containing 0.003% ammonium acetate (w/v) and 0.003% trifluoroacetic acid (v/v) at a flow of 0.3mL/min. All analytes and IS were extracted from rat plasma by a one-step liquid-liquid extraction (LLE) method. The intra- and inter-run accuracies were within 85-115%, and the intra- and inter-run precision were <10% for all analytes. Extraction recoveries were 55-62% for d-threo-MPH, 54-60% for l-threo-MPH, 55-60% for d-threo-EPH, 53-57% for l-threo-EPH and 25-30% for d,l-threo-RA. The validated UFLC-MS/MS method successfully applied to the pharmacokinetic interaction study of oral d-threo-MPH and l-threo-MPH (alone or in combination) in female Sprague Dawley rats. The EPH was not detected in rat plasma following oral administrated MPH without EtOH. As far as it is known to the authors, this study is the first one step liquid-liquid extraction method to extract and UFLC-MS/MS method to quantify d-threo-MPH, l-threo-MPH, d-threo-EPH, l-threo-EPH and d,l-threo-RA simultaneously.

  4. A pulsed field gel electrophoresis (PFGE) study that suggests a major world-wide clone of Salmonella enterica serovar Enteritidis.

    PubMed

    Pang, Jen-Chieh; Chiu, Tsai-Hsin; Helmuth, Reiner; Schroeter, Andreas; Guerra, Beatriz; Tsen, Hau-Yang

    2007-05-30

    Since human infections by Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) have been increasing world-wide over the past years and epidemiological studies have implicated the consumption of meat, poultry, eggs and egg products, elucidation of the predominant subtypes for this Salmonella spp. is important. In this study, 107 poultry and food isolates of Salmonella Enteritidis obtained from Germany were analyzed by pulsed field gel electrophoresis (PFGE), and the subtypes were compared with those of the 124 human isolates obtained in Taiwan. Results showed that for these 107 poultry and food isolates, when XbaI, SpeI and NotI were used for chromosomal DNA digestion followed by PFGE analysis, a total of 19, 20 and 19 PFGE patterns, respectively, were identified. Of them, 51 (47.7%), 52 (48.6%) and 42 (39.3%) strains belong to a single pattern of X3, S3 and N3, respectively, and 34 strains belong to a pattern combination of X3S3N3, which was the major subtype. When PFGE patterns of these 107 German isolates were compared with those of the 124 human isolates obtained in Taiwan, pattern combination of X3S3N3 was found as the most common pattern shared by isolates from both areas. PT4 is a major phage type for German and Taiwan isolates. Although most of the X3S3N3 strains are of this phage type, some strains of other PFGE patterns are also of this phage type. Since strains used in this study were unrelated, i.e., they were isolated from different origins in areas geographically far apart from each other, the PFGE study suggests a major world-wide clone of S. enterica serovar Enteritidis.

  5. Genome-Wide Association Studies Suggest Limited Immune Gene Enrichment in Schizophrenia Compared to 5 Autoimmune Diseases.

    PubMed

    Pouget, Jennie G; Gonçalves, Vanessa F; Spain, Sarah L; Finucane, Hilary K; Raychaudhuri, Soumya; Kennedy, James L; Knight, Jo

    2016-09-01

    There has been intense debate over the immunological basis of schizophrenia, and the potential utility of adjunct immunotherapies. The major histocompatibility complex is consistently the most powerful region of association in genome-wide association studies (GWASs) of schizophrenia and has been interpreted as strong genetic evidence supporting the immune hypothesis. However, global pathway analyses provide inconsistent evidence of immune involvement in schizophrenia, and it remains unclear whether genetic data support an immune etiology per se. Here we empirically test the hypothesis that variation in immune genes contributes to schizophrenia. We show that there is no enrichment of immune loci outside of the MHC region in the largest genetic study of schizophrenia conducted to date, in contrast to 5 diseases of known immune origin. Among 108 regions of the genome previously associated with schizophrenia, we identify 6 immune candidates (DPP4, HSPD1, EGR1, CLU, ESAM, NFATC3) encoding proteins with alternative, nonimmune roles in the brain. While our findings do not refute evidence that has accumulated in support of the immune hypothesis, they suggest that genetically mediated alterations in immune function may not play a major role in schizophrenia susceptibility. Instead, there may be a role for pleiotropic effects of a small number of immune genes that also regulate brain development and plasticity. Whether immune alterations drive schizophrenia progression is an important question to be addressed by future research, especially in light of the growing interest in applying immunotherapies in schizophrenia.

  6. A genome-wide study of panic disorder suggests the amiloride-sensitive cation channel 1 as a candidate gene.

    PubMed

    Gregersen, Noomi; Dahl, Hans A; Buttenschøn, Henriette N; Nyegaard, Mette; Hedemand, Anne; Als, Thomas D; Wang, August G; Joensen, Sofus; Woldbye, David Pd; Koefoed, Pernille; Kristensen, Ann S; Kruse, Torben A; Børglum, Anders D; Mors, Ole

    2012-01-01

    Panic disorder (PD) is a mental disorder with recurrent panic attacks that occur spontaneously and are not associated to any particular object or situation. There is no consensus on what causes PD. However, it is recognized that PD is influenced by environmental factors, as well as genetic factors. Despite a significant hereditary component, genetic studies have only been modestly successful in identifying genes of importance for the development of PD. In this study, we conducted a genome-wide scan using microsatellite markers and PD patients and control individuals from the isolated population of the Faroe Islands. Subsequently, we conducted a fine mapping, which revealed the amiloride-sensitive cation channel 1 (ACCN1) located on chromosome 17q11.2-q12 as a potential candidate gene for PD. The further analyses of the ACCN1 gene using single-nucleotide polymorphisms (SNPs) revealed significant association with PD in an extended Faroese case-control sample. However, analyses of a larger independent Danish case-control sample yielded no substantial significant association. This suggests that the possible risk alleles associated in the isolated population are not those involved in the development of PD in a larger outbred population.

  7. Pelvic nerve innervation of the external sphincter of urethra as suggested by urodynamic and horse-radish peroxidase studies.

    PubMed

    Morita, T; Nishizawa, O; Noto, H; Tsuchida, S

    1984-03-01

    In view of the fact that the detrusor vesicae and external urethral sphincter perform closely synergic functions in micturition, experiments were conducted to explore the action of the pelvic efferent neurons on the external urethral sphincter. The pelvic efferent neurons are generally recognized, by urodynamic assessments and histochemical study with the technique of retrograde axonal transport of horse-radish peroxidase, to innervate the vesical detrusor. In 7 of 15 adult dogs studied, the external urethral sphincter continued to show a normal synergic electromyogram pattern with enhanced electrical activity on vesical distention and disappearance of discharges on vesical contraction even after bilateral transection of the pudendal nerves. The electrical discharges ceased in the sphincter only after subsequent bilateral pelvic neurotomy. Horse-radish peroxidase-positive cells were demonstrated in the intermediolateral and intermediomedial nuclei and in the Onuf nucleus of the sacral cord in approximately half the dogs whose pelvic nerve was injected with the plant peroxidase. The results suggest that the pelvic nerve may contain somatic fibers innervating the external urethral sphincter.

  8. Predictive Studies Suggest that the Risk for the Selection of Antibiotic Resistance by Biocides Is Likely Low in Stenotrophomonas maltophilia

    PubMed Central

    Sánchez, María Blanca; Decorosi, Francesca; Viti, Carlo; Oggioni, Marco Rinaldo; Martínez, José Luis; Hernández, Alvaro

    2015-01-01

    Biocides are used without restriction for several purposes. As a consequence, large amounts of biocides are released without any control in the environment, a situation that can challenge the microbial population dynamics, including selection of antibiotic resistant bacteria. Previous work has shown that triclosan selects Stenotrophomonas maltophilia antibiotic resistant mutants overexpressing the efflux pump SmeDEF and induces expression of this pump triggering transient low-level resistance. In the present work we analyze if two other common biocides, benzalkonium chloride and hexachlorophene, trigger antibiotic resistance in S. maltophilia. Bioinformatic and biochemical methods showed that benzalkonium chloride and hexachlorophene bind the repressor of smeDEF, SmeT. Only benzalkonium chloride triggers expression of smeD and its effect in transient antibiotic resistance is minor. None of the hexachlorophene-selected mutants was antibiotic resistant. Two benzalkonium chloride resistant mutants presented reduced susceptibility to antibiotics and were impaired in growth. Metabolic profiling showed they were more proficient than their parental strain in the use of some dipeptides. We can then conclude that although bioinformatic predictions and biochemical studies suggest that both hexachlorophene and benzalkonium chloride should induce smeDEF expression leading to transient S. maltophilia resistance to antibiotics, phenotypic assays showed this not to be true. The facts that hexachlorophene resistant mutants are not antibiotic resistant and that the benzalkonium chloride resistant mutants presenting altered susceptibility to antibiotics were impaired in growth suggests that the risk for the selection (and fixation) of S. maltophilia antibiotic resistant mutants by these biocides is likely low, at least in the absence of constant selection pressure. PMID:26201074

  9. Predictive Studies Suggest that the Risk for the Selection of Antibiotic Resistance by Biocides Is Likely Low in Stenotrophomonas maltophilia.

    PubMed

    Sánchez, María Blanca; Decorosi, Francesca; Viti, Carlo; Oggioni, Marco Rinaldo; Martínez, José Luis; Hernández, Alvaro

    2015-01-01

    Biocides are used without restriction for several purposes. As a consequence, large amounts of biocides are released without any control in the environment, a situation that can challenge the microbial population dynamics, including selection of antibiotic resistant bacteria. Previous work has shown that triclosan selects Stenotrophomonas maltophilia antibiotic resistant mutants overexpressing the efflux pump SmeDEF and induces expression of this pump triggering transient low-level resistance. In the present work we analyze if two other common biocides, benzalkonium chloride and hexachlorophene, trigger antibiotic resistance in S. maltophilia. Bioinformatic and biochemical methods showed that benzalkonium chloride and hexachlorophene bind the repressor of smeDEF, SmeT. Only benzalkonium chloride triggers expression of smeD and its effect in transient antibiotic resistance is minor. None of the hexachlorophene-selected mutants was antibiotic resistant. Two benzalkonium chloride resistant mutants presented reduced susceptibility to antibiotics and were impaired in growth. Metabolic profiling showed they were more proficient than their parental strain in the use of some dipeptides. We can then conclude that although bioinformatic predictions and biochemical studies suggest that both hexachlorophene and benzalkonium chloride should induce smeDEF expression leading to transient S. maltophilia resistance to antibiotics, phenotypic assays showed this not to be true. The facts that hexachlorophene resistant mutants are not antibiotic resistant and that the benzalkonium chloride resistant mutants presenting altered susceptibility to antibiotics were impaired in growth suggests that the risk for the selection (and fixation) of S. maltophilia antibiotic resistant mutants by these biocides is likely low, at least in the absence of constant selection pressure.

  10. Clinical holistic medicine: a pilot study on HIV and quality of life and a suggested cure for HIV and AIDS.

    PubMed

    Ventegodt, Søren; Flensborg-Madsen, Trine; Andersen, Niels Jørgen; Morad, Mohammed; Merrick, Joav

    2004-05-11

    This study was undertaken to examine the association between the immunological impact of HIV (measured by CD4 count) and global self-assessed quality of life (QOL) (measured with QOL1) for people suffering from HIV, to see if the connection was large and statistically strong enough to support our hypothesis of a strong QOL-immunological connection through the nonspecific, nonreceptor-mediated immune system, and thus to give a rationale for a holistic cure for HIV. This cross-sectional population study in Uganda included 20 HIV infected persons with no symptoms of AIDS and a CD4 count above 200 mill./liter. The main outcome measures were CD4 count, global QOL measured with the validated questionnaire QOL1, translated to Luganda and translated back to English. We found a large, clinically significant correlation between the number of T-helper cells (CD4) and global self-assessed quality of life (QOL1) (r = 0.57, p = 0.021), when controlled for age, gender, and years of infection. Together with other studies and holistic medicine theory, the results have given rationale for a holistic cure for HIV. We suggest, based on our findings and theoretical considerations, that HIV patients who improve their global QOL, also will improve their CD4 counts. Using the technique of holistic medicine based on the life mission theory and the holistic process theory of healing, we hypothesize that the improvement of QOL can have sufficient biological effect on the CD4, which could avoid or postpone the development of AIDS. A holistic HIV/AIDS cure improving the QOL draws on hidden resources in the person and is thus affordable for everybody. Improving global QOL also means a higher consciousness and a more ethical attitude, making it more difficult for the HIV-infected person to pass on the infection.

  11. Comparative Study of different msDNA (multicopy single-stranded DNA) structures and phylogenetic comparison of reverse transcriptases (RTs): evidence for vertical inheritance.

    PubMed

    Das, Rasel; Shimamoto, Tadashi; Hosen, Sultan Mohammad Zahid; Arifuzzaman, Mohammad

    2011-01-01

    The multi-copy single-stranded DNA (msDNA) is yielded by the action of reverse transcriptase of retro-element in a wide range of pathogenic bacteria. Upon this phenomenon, it has been shown that msDNA is only produced by Eubacteria because many Eubacteria species contained reverse transcriptase in their special retro-element. We have screened around 111 Archaea at KEGG (Kyoto Encyclopedia of Genes and Genomes) database available at genome net server and observed three Methanosarcina species (M.acetivorans, M.barkeri and M.mazei), which also contained reverse transcriptase in their genome sequences. This observation of reverse transcriptase in Archaea raises questions regarding the origin of this enzyme. The evolutionary relationship between these two domains of life (Eubacteria and Archaea) hinges upon the phenomenon of retrons. Interestingly, the evolutionary trees based on the reverse transcriptases (RTs) and 16S ribosomal RNAs point out that all the Eubacteria RTs were descended from Archaea RTs during their evolutionary times. In addition, we also have shown some significant structural features among the newly identified msDNA-Yf79 in Yersinia frederiksenii with other of its related msDNAs (msDNA-St85, msDNA-Vc95, msDNA-Vp96, msDNA-Ec78 and msDNA-Ec83) from pathogenic bacteria. Together the degree of sequence conservation among these msDNAs, the evolutionary trees and the distribution of these ret (reverse transcriptase) genes suggest a possible evolutionary scenario. The single common ancestor of the organisms of Eubacteria and Archaea subgroups probably achieved this ret gene during their evolution through the vertical descent rather than the horizontal transformations followed by integration into this organism genome by a mechanism related to phage recognition and/or transposition.

  12. Simultaneous determination of seven alkaloids in rat plasma by UFLC-MS/MS and its application to a pharmacokinetic study after oral administration of Cerebralcare Granule.

    PubMed

    Xiaowen, Li; Ling, Tong; Yunfei, Li; Guoxiang, Sun; Dailin, Yang; Herry, Sun

    2016-04-01

    An ultra fast liquid chromatography-tandem mass sepectrometry (UFLC-MS/MS) method was developed for simultaneous determination of seven active alkaloid components (tetrahydropalmatine, corydaline, α-allocryptopine, tetrahydroberberine, tetrahydrocoptisine, tetrahydrocolumbamine and dehydrocorydaline) in rat plasma after oral administration of Cerebralcare Granule. Plasma samples were pretreated by protein precipitation with acetronitrile containing the internal standard diazepam. Chromatographic separation was achieved on a Phenomenex Kinetex C18 column (100×2.1mm, 2.6μm) with gradient elution using mobile phase consisting of acetonitrile -0.1% formic acid in water at a flow rate of 0.3mL/min. The detection was performed on an electrospray ionization triple quadrupole tandem mass spectrometer using multiple reaction monitoring (MRM) with positive ionization mode. The established method was fully validated and proved to be sensitive and specific with lower limits of quantification (LLOQs) all less than 0.0265ng/mL in rat plasma. Good linearities of seven alkaloids were obtained in respective concentration ranges (r>0.9923). The intra- and inter-day precisions were below of 15% for all the seven alkaloids in terms of relative standard deviation (RSD), and the accuracies were ranged from -2.7% to 8.3% in terms of relative error (RE). Extraction recovery, matrix effect and stability were within the required limits in rat plasma. The validated method was successfully applied to investigate the pharmacokinetics of the seven alkaloids in rat plasma after oral administration of Cerebralcare Granule (CG).

  13. Simultaneous determination and pharmacokinetic study of eight components in rat plasma by UHPLC-MS/MS after oral administration of Hypericum japonicum Thunb extract.

    PubMed

    Pang, Qian; Tian, Yuanyuan; Mi, Jianping; Wang, Jin; Xu, Yuanjin

    2016-01-25

    A rapid and sensitive assay based on ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was established and validated for the simultaneous determination of gallic acid, protocatechuic acid, vanillic acid, caffeic acid, epicatechin, isoquercitrin, vincetoxicoside B and quercetin in rat plasma using catechin and daidzein as the internal standards (IS). Plasma samples added internal standards were acidified with formic acid then pretreated by direct protein precipitation with acetonitrile. The separation of eight constituents was achieved on a C18 column with gradient elution using methanol and 0.2% acetic acid aqueous solution as the mobile phase and detected by multiple reaction monitoring using electrospray ionization source in the positive-negative ionization mode. The method was validated for sufficient specificity, precision, accuracy, and sensitivity over the concentration range of 10-6000 ng mL(-1) for gallic acid, 1.5-3000 ng mL(-1) for protocatechuic acid, 10-15000 ng mL(-1) for vanillic acid, 2-3600 ng mL(-1) for caffeic acid, 1.5-3600 ng mL(-1) for epicatechin, 4-6000 ng mL(-1) for isoquercitrin, 2-9000 ng mL(-1) for vincetoxicoside B, and 20-18000 ng mL(-1) for quercetin. The overall intra‑run precision and the inter‑run precision were showed in the range of 1.0-14.2% and 2.8-12.9%, respectively, and the accuracy was no more than 12.8%. This analytical method was successfully applied to investigate the pharmacokinetics of eight ingredients in rats after oral administration of Hypericum japonicum Thunb extract.

  14. Determination and pharmacokinetic study of gentiopicroside, geniposide, baicalin, and swertiamarin in Chinese herbal formulae after oral administration in rats by LC-MS/MS.

    PubMed

    Lu, Chia-Ming; Lin, Lie-Chwen; Tsai, Tung-Hu

    2014-12-22

    A sensitive and efficient liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of gentiopicroside, geniposide, baicalin, and swertiamarin in rat plasma. To avoid the stress caused by restraint or anesthesia, a freely moving rat model was used to investigate the pharmacokinetics of herbal medicine after the administration of a traditional Chinese herbal prescription of Long-Dan-Xie-Gan-Tang (10 g/kg, p.o.). Analytes were separated by a C18 column with a gradient system of methanol-water containing 1 mM ammonium acetate with 0.1% formic acid. The linear ranges were 10-500 ng/mL for gentiopicroside, geniposide, and baicalin, and 5-250 ng/mL for swertiamarin in biological samples. The intra- and inter-day precision (relative standard deviation) ranged from 0.9% to 11.4% and 0.3% to 14.4%, respectively. The accuracy (relative error) was from -6.3% to 10.1% at all quality control levels. The analytical system provided adequate matrix effect and recovery with good precision and accuracy. The pharmacokinetic data demonstrated that the area under concentration-time curve (AUC) values of gentiopicroside, geniposide, baicalin, and swertiamarin were 1417 ± 83.8, 302 ± 25.8, 753 ± 86.2, and 2.5 ± 0.1 min µg/mL. The pharmacokinetic profiles provide constructive information for the dosage regimen of herbal medicine and also contribute to elucidate the absorption mechanism in herbal applications and pharmacological experiments.

  15. HPLC and LC-MS analysis of sinomenine and its application in pharmacokinetic studies in rats

    PubMed Central

    Long, Li-hong; Wu, Peng-fei; Chen, Xiang-long; Zhang, Zui; Chen, Yu; Li, Yi-yong; Jin, You; Chen, Jian-guo; Wang, Fang

    2010-01-01

    Aim: To improve and validate analytical methods based on HPLC and liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the quantitative measurement of sinomenine in rat plasma and brain tissue. Methods: The separation of analytes and the internal standard (IS), chloramphenicol, was performed on an Agilent TC-C18 column (250×4.6 mm, 5 μm). Blood samples were measured with a Surveyor photodiode array (PDA) detector at a wavelength of 263 nm. The LCQ DECA XPPlus mass spectrometer was operated in the multiple reactions monitoring mode using positive electrospray ionization, and the transition from the precursor ion (m/z 279) to the product ion (m/z 224) for sinomenine was measured in brain tissue. Results: Measurements were linear over the concentration range of 0.1–100 μg/mL for sinomenine in plasma and over the range of 0.01–5.00 μg/g for sinomenine in brain tissue. The intra- and inter-day variabilities were less than 10% of the relative standard deviation (RSD), and the extraction and recovery of sinomenine was 72.48%–80.26% from plasma and 73.75%–80.26% from brain tissue. The limit of quantification (LOQ) was 0.1 μg/mL for plasma, and 0.01 μg/g for brain tissue. Identification of sinomenine was reproducible at 0.5, 5, and 50 μg/mL in the plasma and at 0.05, 0.50, and 2.00 μg/g in brain tissue. The concentration of sinomenine measured in brain tissue after a single ip dose had a neuroprotective effect on H2O2-induced injury in PC12 cells in vitro. Conclusion: Our methods offered a sensitivity within a wide linear concentration range for sinomenine. These methods were successfully applied to evaluate sinomenine pharmacokinetics over time in rat brain tissue after a single ip dose of 30 mg/kg. PMID:20871622

  16. An international observational study suggests that artificial intelligence for clinical decision support optimizes anemia management in hemodialysis patients.

    PubMed

    Barbieri, Carlo; Molina, Manuel; Ponce, Pedro; Tothova, Monika; Cattinelli, Isabella; Ion Titapiccolo, Jasmine; Mari, Flavio; Amato, Claudia; Leipold, Frank; Wehmeyer, Wolfgang; Stuard, Stefano; Stopper, Andrea; Canaud, Bernard

    2016-08-01

    Managing anemia in hemodialysis patients can be challenging because of competing therapeutic targets and individual variability. Because therapy recommendations provided by a decision support system can benefit both patients and doctors, we evaluated the impact of an artificial intelligence decision support system, the Anemia Control Model (ACM), on anemia outcomes. Based on patient profiles, the ACM was built to recommend suitable erythropoietic-stimulating agent doses. Our retrospective study consisted of a 12-month control phase (standard anemia care), followed by a 12-month observation phase (ACM-guided care) encompassing 752 patients undergoing hemodialysis therapy in 3 NephroCare clinics located in separate countries. The percentage of hemoglobin values on target, the median darbepoetin dose, and individual hemoglobin fluctuation (estimated from the intrapatient hemoglobin standard deviation) were deemed primary outcomes. In the observation phase, median darbepoetin consumption significantly decreased from 0.63 to 0.46 μg/kg/month, whereas on-target hemoglobin values significantly increased from 70.6% to 76.6%, reaching 83.2% when the ACM suggestions were implemented. Moreover, ACM introduction led to a significant decrease in hemoglobin fluctuation (intrapatient standard deviation decreased from 0.95 g/dl to 0.83 g/dl). Thus, ACM support helped improve anemia outcomes of hemodialysis patients, minimizing erythropoietic-stimulating agent use with the potential to reduce the cost of treatment.

  17. Simultaneous determination of ten alkaloids of crude and wine-processed Rhizoma Coptidis aqueous extracts in rat plasma by UHPLC-ESI-MS/MS and its application to a comparative pharmacokinetic study.

    PubMed

    Qian, Xiao-Cui; Zhang, Liang; Tao, Yi; Huang, Ping; Li, Jun-Song; Chai, Chuan; Li, Wen; Di, Liu-Qing; Cai, Bao-Chang

    2015-02-01

    Rhizoma coptidis (R.C.), a widely used traditional Chinese medicine, has been used for centuries in the treatment of hypertension, inflammation, dysentery and liver diseases, etc. Wine-processing is a specialized technology by sautéing crude herbal medicine using Chinese rice wine. This paper was designed to establish a simultaneous quantitative method of ten alkaloids (berberine, coptisine, palmatine, jatrorrhizine, epiberberine, magnoflorine, columbamine, noroxyhydrastinine, oxyberberine and 8-oxocoptisine) in rat plasma. Furthermore, the pharmacokinetics of those alkaloids after administration of crude and wine-processed R.C. aqueous extracts was compared. As a result, a ultra high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) method was developed and validated for the first time. Chromatographic separation was achieved on a C18 column using gradient elution with the mobile phase consisting of acetonitrile and water (containing 0.2% formic acid) at a flow rate of 0.2 ml/min. The validated method showed good linearity over a wide concentration range (r>0.99), and lower limits of quantification less than 5.46 ng/ml for the each analyte. The intra- and inter-day assay variability was below 9.9% and 10.5% for all analytes, respectively. The extraction recovery of those alkaloids and I.S. ranged from 65.3% to 90.7%. The validated method has been successfully applied to pharmacokinetic comparison after administration of crude and wine-processed R.C. aqueous extracts. Pharmacokinetic comparative study showed that Cmax of coptisine and 8-oxocoptisine and AUC0-t of coptisine, palmatine and 8-oxocoptisine were increased significantly (p<0.05) after wine-processing, while other compounds didn't show significant difference, which suggested that wine-processing exerted limited effects on the absorption of alkaloids. These results might be helpful for R.C.' clinical reasonable application and further studies on its wine

  18. Elemental fingerprinting of soils using ICP-MS and multivariate statistics: a study for and by forensic chemistry majors.

    PubMed

    Reidy, Lorlyn; Bu, Kaixuan; Godfrey, Murrell; Cizdziel, James V

    2013-12-10

    Students in an instrumental analysis course with a forensic emphasis were presented with a mock scenario in which soil was collected from a murder suspect's car mat, from the crime scene, from adjacent areas, and from more distant locations. Students were then asked to conduct a comparative analysis using the soil's elemental distribution fingerprints. The soil was collected from Lafayette County, Mississippi, USA and categorized as sandy loam. Eight student groups determined twenty-two elements (Li, Be, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Cs, Ba, Pb, U) in seven samples of soil and one sample of sediment by microwave-assisted acid digestion and inductively coupled plasma-mass spectrometry (ICP-MS). Data were combined and evaluated using multivariate statistical analyses. All eight student groups correctly classified their unknown among the different locations. Students learn, however, that whereas their results suggest that the elemental fingerprinting approach can be used to distinguish soils from different land-use areas and geographic locations, applying the methodology in forensic investigations is more complicated and has potential pitfalls. Overall, the inquiry-based pedagogy enthused the students and provided learning opportunities in analytical chemistry, including sample preparation, ICP-MS, figures-of-merit, and multivariate statistics.

  19. A genome-wide association study follow-up suggests a possible role for PPARG in systemic sclerosis susceptibility

    PubMed Central

    2014-01-01

    Introduction A recent genome-wide association study (GWAS) comprising a French cohort of systemic sclerosis (SSc) reported several non-HLA single-nucleotide polymorphisms (SNPs) showing a nominal association in the discovery phase. We aimed to identify previously overlooked susceptibility variants by using a follow-up strategy. Methods Sixty-six non-HLA SNPs showing a P value <10-4 in the discovery phase of the French SSc GWAS were analyzed in the first step of this study, performing a meta-analysis that combined data from the two published SSc GWASs. A total of 2,921 SSc patients and 6,963 healthy controls were included in this first phase. Two SNPs, PPARG rs310746 and CHRNA9 rs6832151, were selected for genotyping in the replication cohort (1,068 SSc patients and 6,762 healthy controls) based on the results of the first step. Genotyping was performed by using TaqMan SNP genotyping assays. Results We observed nominal associations for both PPARG rs310746 (PMH = 1.90 × 10-6, OR, 1.28) and CHRNA9 rs6832151 (PMH = 4.30 × 10-6, OR, 1.17) genetic variants with SSc in the first step of our study. In the replication phase, we observed a trend of association for PPARG rs310746 (P value = 0.066; OR, 1.17). The combined overall Mantel-Haenszel meta-analysis of all the cohorts included in the present study revealed that PPARG rs310746 remained associated with SSc with a nominal non-genome-wide significant P value (PMH = 5.00 × 10-7; OR, 1.25). No evidence of association was observed for CHRNA9 rs6832151 either in the replication phase or in the overall pooled analysis. Conclusion Our results suggest a role of PPARG gene in the development of SSc. PMID:24401602

  20. TG-MS study of the thermo-oxidative behavior of plastic automobile shredder residues.

    PubMed

    Guo, Qingjie; Zhang, Xuan; Li, Chao; Liu, Xinmin; Li, Jinhui

    2012-03-30

    Automobile shredder residues (ASR) are materials that are rejected in the metal recovery process for end-of-life vehicles (ELV). These residues are composed of such materials as plastics, foams, glasses, rubbers, textiles, remaining metals and soils. ASR disposal is a difficult task, due to increasingly restrictive re-use policies. The pyrolytic reuse of ASR is one important option for energy recovery. The gas release behavior of pyrolyzed ASR was measured using a TG-MS apparatus, and this thermo-oxidative process was observed under different N(2)/O(2) volume ratios. The final weight/initial residue weight ratio for pyrolyzed ASR decreased from 43.4% to 10.1% with increasing oxygen concentrations. The production rates of hydrogen, methane and carbon dioxide also varied with different N(2)/O(2) volume ratios. The maximum emission of hydrogen and methane occurred when the thermo-oxidative atmosphere was entirely N(2). Temperature had a positive impact on hydrogen production, and the methane emission ratio reached a peak at the second shoulder of the devolatilization stage during which stage organic polymers were emitted. A peculiar characteristic of ASR is its content of nitrogen. The effects of ASR nitrogen content on N(2)O and NO(X) emissions were investigated in detail. NH(3) was the dominant nitrogen species that was released during ASR pyrolysis. N(2)O is highly temperature-sensitive and decomposes to N(2) at temperatures greater than 900°C.

  1. HPTLC and GC/MS Study of Amaryllidaceae Alkaloids of Two Narcissus Species.

    PubMed

    Shawky, Eman; Abou-Donia, Amina H; Darwish, Fikria A; Toaima, Soad M; Takla, Sarah S; Pigni, Natalia B; Bastida, Jaume

    2015-08-01

    In this article, we report on the alkaloid profile and dynamic of alkaloid content and diversity in two Narcissus plants at different stages of development. The alkaloid profile of the two Narcissus species was investigated by GC/MS and HPTLC. Fifty eight Amaryllidaceae alkaloids were detected, and 25 of them were identified in the different organs of N. tazetta and N. papyraceus. The alkaloid 3-O-methyl-9-O-demethylmaritidine is tentatively identified here for the first time from the Amaryllidaceae family, and four alkaloids (tazettamide, sternbergine, 1-O-acetyllycorine, 2,11-didehydro-2-dehydroxylycorine) are tentatively identified for the first time in the genus Narcissus. The different organs of the two species analyzed showed remarkable differences in their alkaloid pattern, type of biosynthesis, main alkaloid and number of alkaloids. Lycorine-type alkaloids dominated the alkaloid, metabolism in N. papyraceus, while alkaloids of narciclasine-, galanthamine- and homolycorine-types were found only in the species N. tazetta L.

  2. MS Based Metabonomics

    SciTech Connect

    Want, Elizabeth J.; Metz, Thomas O.

    2010-03-01

    1. Gas chromatography-(GC)-MS was the most commonly used MS-based method for small molecule analysis in the 1970s and 1980s. It is still used today for the detection of many metabolic disorders and plays a strong role in plant metabonomics. Liquid chromatography (LC)-MS approaches have grown in popularity for metabolite studies, due to simpler sample preparation, reduced analysis times through the introduction of ultra-high performance liquid chromatography (UPLC)-MS and the ability to observe a wider range of metabolites. This chapter will discuss the role of MS in metabonomics, the techniques involved in this exciting area, and the current and future applications of the field. The various bioinformatics tools and multivariate analysis techniques used to maximize information recovery and to aid in the interpretation of the very large data sets typically obtained in metabonomics studies will also be discussed. While there are many different MS-based approaches utilized in metabonomics studies, emphasis will be placed on more established methods.

  3. A rapid and sensitive LC-MS/MS method for quantification of quercetin-3-O-β-d-glucopyranosyl-7-O-β-d-gentiobioside in plasma and its application to a pharmacokinetic study.

    PubMed

    He, Xin; Tao, Guizhou; Gao, Hang; Li, Keyan; Zhang, Yazhuo; Sun, Limin; Zhang, Yingjie

    2016-09-01

    A rapid and sensitive LC-MS/MS method with good accuracy and precision was developed and validated for the pharmacokinetic study of quercetin-3-O-β-d-glucopyranosyl-7-O-β-d-gentiobioside (QGG) in Sprague-Dawley rats. Plasma samples were simply precipitated by methanol and then analyzed by LC-MS/MS. A Venusil® ASB C18 column (2.1 × 50 mm, i.d. 5 μm) was used for separation, with methanol-water (50:50, v/v) as the mobile phase at a flow rate of 300 μL/min. The optimized mass transition ion-pairs (m/z) for quantitation were 787.3/301.3 for QGG, and 725.3/293.3 for internal standard. The linear range was 7.32-1830 ng/mL with an average correlation coefficient of 0.9992, and the limit of quantification was 7.32 ng/mL. The intra- and inter-day precision and accuracy were less than ±15%. At low, medium and high quality control concentrations, the recovery and matrix effect of the analyte and IS were in the range of 89.06-92.43 and 88.58-97.62%, respectively. The method was applied for the pharmacokinetic study of QGG in Sprague-Dawley rats. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Stopped-Flow Studies of the Reduction of the Copper Centers Suggest a Bifurcated Electron Transfer Pathway in Peptidylglycine Monooxygenase.

    PubMed

    Chauhan, Shefali; Hosseinzadeh, Parisa; Lu, Yi; Blackburn, Ninian J

    2016-04-05

    Peptidylglycine monooxygenase (PHM) is a dicopper enzyme that plays a vital role in the amidation of glycine-extended pro-peptides. One of the crucial aspects of its chemistry is the transfer of two electrons from an electron-storing and -transferring site (CuH) to the oxygen binding site and catalytic center (CuM) over a distance of 11 Å during one catalytic turnover event. Here we present our studies of the first electron transfer (ET) step (reductive phase) in wild-type (WT) PHM as well as its variants. Stopped flow was used to record the reduction kinetic traces using the chromophoric agent N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) as the reductant. The reduction was found to be biphasic in the WT PHM with an initial fast phase (17.2 s(-1)) followed by a much slower phase (0.46 s(-1)). We were able to ascribe the fast and slow phase to the CuH and CuM sites, respectively, by making use of the H242A and H107AH108A mutants that contain only the CuH site and CuM site, respectively. In the absence of substrate, the redox potentials determined by cyclic voltammetry were 270 mV (CuH site) and -15 mV (CuM site), but binding of substrate (Ac-YVG) was found to alter both potentials so that they converged to a common value of 83 mV. Substrate binding also accelerated the slow reductive phase by ~10-fold, an effect that could be explained at least partially by the equalization of the reduction potential of the copper centers. Studies of H108A showed that the ET to the CuM site is blocked, highlighting the role of the H108 ligand as a component of the reductive ET pathway. Strikingly, the rate of reduction of the H172A variant was unaffected despite the rate of catalysis being 3 orders of magnitude slower than that of the WT PHM. These studies strongly indicate that the reductive phase and catalytic phase ET pathways are different and suggest a bifurcated ET pathway in PHM. We propose that H172 and Y79 form part of an alternate pathway for the catalytic phase

  5. Simultaneous determination of imperatorin and its metabolite xanthotoxol in rat plasma and urine by LC-MS/MS and its application to pharmacokinetic studies.

    PubMed

    Ngo, Lien; Tran, Phuong; Ham, Seong-Ho; Cho, Jung-Hee; Cho, Hea-Young; Lee, Yong-Bok

    2017-02-15

    An accurate, precise, selective, and sensitive liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of imperatorin (IMP) and its metabolite, xanthotoxol (XAN), in rat plasma and urine samples. The analytes, along with psoralen as an internal standard, were determined by multiple reaction monitoring (MRM) operated in the positive electrospray ionization (ESI) mode. Chromatographic separation was performed on an Acquity UPLC BEH C18 column (50mm×2.1mm, 1.7μm) with a mobile phase consisting of 0.1% formic acid solution and 0.1% formic acid in methanol at a flow rate of 0.3mL/min. The run time was 6min per sample and the injection volume was 5μL. The method had a lower limit of quantification (LLOQ) of 0.25ng/mL for IMP in plasma and urine, and 1ng/mL for XAN in urine. The linear calibration curves were fitted over the range of 0.25-1000ng/mL for IMP in plasma, 0.25-1000ng/mL for IMP in urine, and 1-1000ng/mL for XAN in urine, with correlation coefficients greater than 0.995. The inter- and intra-day accuracies (relative error, RE%) were between -8.5% and 3.5%, and the precisions (relative standard deviation, RSD%) were less than 10.0% for all quality control samples (QCs). The analytes were extracted from rat plasma and urine samples using a liquid-liquid extraction method with the extraction recovery in the range of 60.3-79.1%. A good stability of the analytes was observed in all the analysis procedures. The method was successfully validated and applied to determine the pharmacokinetics of IMP in rat plasma and, for the first time, the metabolite kinetics of IMP to XAN in rat urine after IMP administration.

  6. An improved LC-MS/MS method for the simultaneous determination of pyrazinamide, pyrazinoic acid and 5-hydroxy pyrazinoic acid in human plasma for a pharmacokinetic study.

    PubMed

    Shah, Priyanka A; Sharma, Primal; Shah, Jaivik V; Sanyal, Mallika; Shrivastav, Pranav S

    2016-04-01

    In the present work the plasma levels of PZA and its two active metabolites, pyrazinoic acid (PA) and 5-hydroxy pyrazinoic acid (5-OH PA) were determined by a sensitive and rapid LC-MS/MS method. The analytes and their labeled internal standards were extracted from 200μL plasma samples by liquid-liquid extraction with methyl tert-butyl ether: diethyl ether (90:10, v/v) under acidic conditions. Their separation was achieved on a Zorbax Eclipse XDB C18 (100×4.6mm, 3.5μm) column using methanol and 0.1% acetic acid (65:35, v/v) as the mobile phase within 4.0min. Detection and quantitation were done by multiple reaction monitoring on a triple quadrupole mass spectrometer following the transitions, m/z 124.1→81.1,m/z 125.0→80.9 and m/z 141.0→81.0 for PZA, PA and 5-OH PA respectively in the positive ionization mode. All the analytes were baseline resolved with a resolution factor of 3.3 and 6.4 between PZA and its metabolites, PA and 5-OH PA respectively. The calibration curves were linear from 0.100-30.0μg/mL, 0.03-9.00μg/mL and 0.002-0.600μg/mL for PZA, PA and 5-OH PA respectively with r(2)≥0.9980 for all the analytes. The intra-batch and inter-batch accuracy and precision (% CV) across quality controls varied from 93.5-106.7% and 1.10-4.57 respectively for all the analytes. The mean extraction recovery of PZA, PA and 5-OH PA was 83.7%, 89.2% and 80.8% respectively, which was consistent at higher as well as lower concentration levels. The% change in the stability of analytes under different storage conditions ranged -6.7 to 7.1 for all the analytes. The method was applied to assess the comparative bioavailability of a 500mg PZA test and reference formulation in healthy subjects. The assay reproducibility was also tested by reanalysis of 22 incurred subject samples.

  7. Development and validation of a sensitive LC-MS/MS assay for the quantification of nizatidine in human plasma and urine and its application to pharmacokinetic study.

    PubMed

    Shang, De-Wei; Wang, Zhan-Zhang; Ni, Xiao-Jia; Zhang, Ming; Hu, Jin-Qing; Qiu, Chang; Wen, Yu-Guan

    2015-08-15

    We developed and validated a high performance liquid chromatographic method coupled with triple quadrupole mass spectrometry for analysis of nizatidine in human plasma and urine. The biological samples were precipitated with methanol before separation on an Agilent Eclipse Plus C18 column (100mm×46mm, 5μm) with a mixture of methanol and water (95:5, plus 5mM ammonium formate) as the mobile phase at 0.5mL/min. Detection was performed using multiple reaction monitoring modes via electrospray ionization (ESI) at m/z 332.1→155.1 (for nizatidine) and m/z 335.1→155.1 (for [(2)H3]-nizatidine, the internal standard). The linear response range was 5-2000ng/mL and 0.5-80μg/mL for human plasma and urine, with the lower limits of quantification of 5ng/mL and 0.5μg/mL, respectively. The method was validated according to the biological method validation guidelines of the Food and Drug Administration and proved acceptable. This newly developed analytical method was successfully applied in a pharmacokinetic study following single oral administration of a 150mg nizatidine capsule in to 16 healthy Chinese subjects. Maximum and endpoint concentrations in plasma and urine were quantifiable, suggesting our method is appropriate for routine pharmacokinetic analysis.

  8. GC-MS Study of Mono- and Bishaloethylphosphonates Related to Schedule 2.B.04 of the Chemical Weapons Convention: The Discovery of a New Intramolecular Halogen Transfer.

    PubMed

    Picazas-Márquez, Nerea; Sierra, María; Nova, Clara; Moreno, Juan Manuel; Aboitiz, Nuria; de Rivas, Gema; Sierra, Miguel A; Martínez-Álvarez, Roberto; Gómez-Caballero, Esther

    2016-09-01

    A new class of compounds, mono- and bis-haloethylphosphonates (HAPs and bisHAPs, respectively), listed in Schedule 2.B.04 of the Chemical Weapons Convention (CWC), has been synthesized and studied by GC-MS with two aims. First, to improve the identification of this type of chemicals by the Organization for the Prohibition of Chemical Weapons, (OPCW). Second, to study the synergistic effect of halogen and silicon atoms in molecules undergoing mass spectrometry. Fragmentation patterns of trimethylsilyl derivatives of HAPs were found to depend on the nature of the halogen atom; this was in agreement with DFT-calculations. The data suggest that a novel intramolecular halogen transfer takes place during the fragmentation process. Graphical Abstract ᅟ.

  9. GC-MS Study of Mono- and Bishaloethylphosphonates Related to Schedule 2.B.04 of the Chemical Weapons Convention: The Discovery of a New Intramolecular Halogen Transfer

    NASA Astrophysics Data System (ADS)

    Picazas-Márquez, Nerea; Sierra, María; Nova, Clara; Moreno, Juan Manuel; Aboitiz, Nuria; de Rivas, Gema; Sierra, Miguel A.; Martínez-Álvarez, Roberto; Gómez-Caballero, Esther

    2016-09-01

    A new class of compounds, mono- and bis-haloethylphosphonates (HAPs and bisHAPs, respectively), listed in Schedule 2.B.04 of the Chemical Weapons Convention (CWC), has been synthesized and studied by GC-MS with two aims. First, to improve the identification of this type of chemicals by the Organization for the Prohibition of Chemical Weapons, (OPCW). Second, to study the synergistic effect of halogen and silicon atoms in molecules undergoing mass spectrometry. Fragmentation patterns of trimethylsilyl derivatives of HAPs were found to depend on the nature of the halogen atom; this was in agreement with DFT-calculations. The data suggest that a novel intramolecular halogen transfer takes place during the fragmentation process.

  10. The complex between ribonuclease T1 and 3'GMP suggests geometry of enzymic reaction path. An X-ray study.

    PubMed

    Heydenreich, A; Koellner, G; Choe, H W; Cordes, F; Kisker, C; Schindelin, H; Adamiak, R; Hahn, U; Saenger, W

    1993-12-15

    The crystal structure of the complex between ribonuclease T1 and 3'GMP suggests that (a) a substrate GpN is bound to the active site of ribonuclease T1 in a conformation that actively supports the catalytic process, (b) the reaction occurs in an in-line process, (c) His40 N epsilon H+ activates O2'-H, (d) Glu58 carboxylate acts as base and His92 N epsilon H+ as acid in a general acid-base catalysis. The crystals have the monoclinic space group P2(1), a = 4.968 nm, b = 4.833 nm, c = 4.048 nm, beta = 90.62 degrees with two molecules in the asymmetric unit. The structure was determined by molecular replacement and refined to R = 15.3% with 11,338 data > or = 1 sigma (Fo) in the resolution range 1.0-0.2 nm; this includes 180 water molecules and two Ca2+. The structure of ribonuclease T1 is as previously observed. 3'GMP is bound in syn conformation; guanine is located in the specific recognition site, the ribose adopts C4'-exo puckering, the ribose phosphate is extended with torsion angle epsilon in trans. The O2'-H group is activated by accepting and donating hydrogen bonds from His40 N epsilon H+ and to Glu58 O epsilon 1; the phosphate is hydrogen bonded to Glu58 O epsilon 2H, Arg77 N epsilon H+ and N eta 2H+, Tyr38 O eta H, His92 N eta H+. The conformation of ribose phosphate is such that O2' is at a distance of 0.31 nm from phosphorus, and opposite the P-OP3 bond which accepts a hydrogen bond from His92 N epsilon H+; we infer from a model building study that this bond is equivalent to the scissile P-O5' in a substrate GpN.

  11. Sorption of Eu(III) on granite: EPMA, LA-ICP-MS, batch and modeling studies.

    PubMed

    Fukushi, Keisuke; Hasegawa, Yusuke; Maeda, Koushi; Aoi, Yusuke; Tamura, Akihiro; Arai, Shoji; Yamamoto, Yuhei; Aosai, Daisuke; Mizuno, Takashi

    2013-11-19

    Eu(III) sorption on granite was assessed using combined microscopic and macroscopic approaches in neutral to acidic conditions where the mobility of Eu(III) is generally considered to be high. Polished thin sections of the granite were reacted with solutions containing 10 μM of Eu(III) and were analyzed using EPMA and LA-ICP-MS. On most of the biotite grains, Eu enrichment up to 6 wt % was observed. The Eu-enriched parts of biotite commonly lose K, which is the interlayer cation of biotite, indicating that the sorption mode of Eu(III) by the biotite is cation exchange in the interlayer. The distributions of Eu appeared along the original cracks of the biotite. Those occurrences indicate that the prior water-rock interaction along the cracks engendered modification of biotite to possess affinity to the Eu(III). Batch Eu(III) sorption experiments on granite and biotite powders were conducted as functions of pH, Eu(III) loading, and ionic strength. The macroscopic sorption behavior of biotite was consistent with that of granite. At pH > 4, there was little pH dependence but strong ionic strength dependence of Eu(III) sorption. At pH < 4, the sorption of Eu(III) abruptly decreased with decreased pH. The sorption behavior at pH > 4 was reproducible reasonably by the modeling considering single-site cation exchange reactions. The decrease of Eu(III) sorption at pH < 4 was explained by the occupation of exchangeable sites by dissolved cationic species such as Al and Fe from granite and biotite in low-pH conditions. Granites are complex mineral assemblages. However, the combined microscopic and macroscopic approaches revealed that elementary reactions by a single mineral phase can be representative of the bulk sorption reaction in complex mineral assemblages.

  12. Impact of Exercise and Aging on Rat Urine and Blood Metabolome. An LC-MS Based Metabolomics Longitudinal Study

    PubMed Central

    Deda, Olga; Gika, Helen G.; Taitzoglou, Ioannis; Raikos, Νikolaos; Theodoridis, Georgios

    2017-01-01

    Aging is an inevitable condition leading to health deterioration and death. Regular physical exercise can moderate the metabolic phenotype changes of aging. However, only a small number of metabolomics-based studies provide data on the effect of exercise along with aging. Here, urine and whole blood samples from Wistar rats were analyzed in a longitudinal study to explore metabolic alterations due to exercise and aging. The study comprised three different programs of exercises, including a life-long protocol which started at the age of 5 months and ended at the age of 21 months. An acute exercise session was also evaluated. Urine and whole blood samples were collected at different time points and were analyzed by LC-MS/MS (Liquid Chromatography–tandem Mass Spectrometry). Based on their metabolic profiles, samples from trained and sedentary rats were differentiated. The impact on the metabolome was found to depend on the length of exercise period with acute exercise also showing significant changes. Metabolic alterations due to aging were equally pronounced in sedentary and trained rats in both urine and blood analyzed samples. PMID:28241477

  13. Simultaneous determination of five free and total flavonoids in rat plasma by ultra HPLC-MS/MS and its application to a comparative pharmacokinetic study in normal and hyperlipidemic rats.

    PubMed

    Wang, Xiaofan; Zhao, Xu; Gu, Liqiang; Lv, Chunxiao; He, Bosai; Liu, Zhenzhen; Hou, Pengyi; Bi, Kaishun; Chen, Xiaohui

    2014-03-15

    A simple and rapid ultra-high performance liquid chromatography-tandem mass spectrometry (uHPLC-MS/MS) method has been developed for the simultaneous determination of five free flavonoids (amentoflavone, isorhamnetin, naringenin, kaempferol and quercetin) and their total (free and conjugated) forms, and to compare the pharmacokinetics of these active ingredients in normal and hyperlipidemic rats. The free and total forms of these flavonoids were extracted by liquid-liquid extraction with ethyl acetate. The conjugated flavonoids were deconjugated by the enzyme β-Glucuronidase and Sulfatase. Chromatographic separation was accomplished on a ZORBAX Eclipse XDB-C8 USP L7 column using gradient elution. Detection was performed on a 4000Q uHPLC-MS/MS system from AB Sciex using negative ion mode in the multiple reaction monitoring (MRM) mode. The lower limits of quantification were 2.0-5.0ng/mL for all the analytes. Intra-day and inter-day precision were less than 15% and accuracy ranged from -9.3% to 11.0%, and the mean extraction recoveries of analytes and internal standard (IS) from rat plasma were all more than 81.7%. The validated method was successfully applied to a comparative pharmacokinetic study of five free and total analytes in rat plasma. The results indicated that the absorption of five total flavonoids in hyperlipidemia group were significantly higher than those in normal group with similar concentration-time curves.

  14. Development, optimization and validation of a highly sensitive UPLC-ESI-MS/MS method for simultaneous quantification of amlodipine, benazeprile and benazeprilat in human plasma: application to a bioequivalence study.

    PubMed

    Rezk, Mamdouh R; Badr, Kamal A

    2014-09-01

    A rapid, simple, sensitive and specific LC-MS/MS method has been developed and validated for the simultaneous estimation of amlodipine (AML), benazepril (BEN) and benazeprilat (BNT) using eplerenone and torsemide as internal standards (IS). The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Sample preparation involves both extraction and precipitation techniques. The reconstituted samples were chromatographed on Acquity UPLC BEH C18 (50mm×2.1mm, 1.7μm) column by pumping 0.1% formic acid and acetonitrile in a gradient mode at a flow rate of 0.45ml/min. A detailed validation of the method was performed as per the FDA guidelines and the standard curves were found to be linear in the range of 0.1-5ng/ml for AML; 5-1200ng/ml for both BEN and BNT. The intra-day and inter-day precision and accuracy results were within the acceptable limits. A run time of 2.5min for each sample made it possible to analyze more than 300 human plasma samples per day. The developed assay method was successfully applied to a bioequivalence study in human volunteers.

  15. Ultra-fast LC-ESI-MS/MS method for the simultaneous determination of six highly toxic Aconitum alkaloids from Aconiti kusnezoffii radix in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Liu, Jingjing; Li, Qing; Yin, Yidi; Liu, Ran; Xu, Huarong; Bi, Kaishun

    2014-01-01

    A fast, sensitive, and efficient ultra-fast LC-ESI-MS/MS method was developed for the simultaneous quantitation of six highly toxic Aconitum alkaloids, that is, aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, in rat plasma after oral administration of crude ethanol extracts from Aconiti kusnezoffii radix by ultrasonic extraction, reflux extraction for 1 h, and reflux extraction for 3 h, respectively. The separation of six Aconitum alkaloids and aminopyrine (internal standard) was performed on an InertSustain® C18 column, and the quantification of the analytes was performed on a 4000Q ultra-fast LC-MS/MS system with turbo ion spray source in the positive ion and multiple-reaction monitoring mode. Absolute recoveries ranged within 65.06-85.1% for plasma samples. The intra- and interday precision and accuracy of analytes were satisfactory. The methods were validated with sensitivity reaching the lower LOQ for aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, which were 0.025, 0.025, 0.050, 0.025, 0.025, and 0.100 ng/mL, respectively. The method was successfully applied to a pharmacokinetic study of six Aconitum alkaloids in rat plasma after oral administration of crude ethanol extracts from the raw root of Aconitum kusnezoffii Reichb. by three different extraction processes.

  16. Determination of cannabinoids in hemp nut products in Taiwan by HPLC-MS/MS coupled with chemometric analysis: quality evaluation and a pilot human study.

    PubMed

    Chang, Chih-Wei; Tung, Chun-Wei; Tsai, Chin-Chuan; Wu, Yu-Tse; Hsu, Mei-Chich

    2016-09-02

    Hemp nuts are mature cannabis seeds obtained after shelling and that are commonly used in traditional Chinese medicine for treating functional constipation. In this work, we screened hemp nut products, classified them, and verified the legality of consuming them. A total of 18 products were purchased from Taiwan, China, and Canada. Validated high-performance liquid chromatography with tandem mass spectrometry methods were developed for analyzing the cannabinoid (i.e., Δ(9) -tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol) content of the products and the concentration of urinary 11-nor-9-carboxy-THC. Chemometric techniques, namely hierarchical clustering analysis (HCA) and principal component analysis (PCA), were applied for rapidly classifying 11 concentrated powder products in Taiwan. A pilot human study comprising single and multiple administrations of a product with 1.5 µg/g of THC was conducted to examine the urinary 11-nor-9-carboxy-THC concentration. Through optimization of 3(2) full factorial design, using 60% isopropanol as the extraction solvent exhibited the highest yield of cannabinoids and was applied as the optimal condition in further analysis. The results of HCA and PCA on quality evaluation were in good agreement; however, the tested products possessed distinct CBD-to-THC ratios which ranged widely from 0.1:1 to 46.8:1. Particularly, the products with CBD-to-THC ratios higher than 1:1 were the majority in Taiwan. Our data suggested that all the tested hemp nut products met the Taiwan restriction criterion of 10 µg/g of THC. We propose a usual consumption amount of hemp nut products in Taiwan would unlikely to violate the cut-off point of 15 ng/mL of urinary 11-nor-9-carboxy-THC. Copyright © 2016 John Wiley & Sons, Ltd.

  17. LC-MS-MS analysis of 2-pyridylacetic acid, a major metabolite of betahistine: application to a pharmacokinetic study in healthy volunteers.

    PubMed

    Chen, X Y; Zhong, D F; Duan, J L; Yan, B X

    2003-12-01

    1. A sensitive liquid chromatographic-tandem mas spectrometric assay was developed and validated to determine the major metabolite of betahistine, 2-pyridylacetic acid, in human plasma. 2. The analyte was extracted from plasma samples by liquid-liquid extraction and analysed using liquid chromatography-tandem mass spectrometry with an electrospray ionization interface. The method has a lower limit of quantitation of 1 ng ml(-1) fir a 0.5-ml plasma aliquot. The intra- and interday precision (relative standard deviation), calculated from quality control (QC) samples, was less than 10%. Accuracy as determined from QC samples was within +/-7%. 3. The validated method was successfully applied to a pharmacokinetic study of betahistine in healthy volunteers. After oral administration of a single dose of 24 mg betahistine mesylate to 20 healthy Chinese male volunteers, Cmax was 339.4 ng ml(-1) (range 77.3-776.4 ng ml(-1)). The t(1/2) was 5.2 h (range 2.0(-1)-11.4h). The AUC(0-t) obtained was 1153.5 ng ml(-1) h (range 278.5-3150.8 ng ml(-1)). The disposition of the metabolite exhibited a marked interindividual variation. 4. The plasma concentrations of the parent drug were less than 0.5 ng ml(-1), suggesting that it undergoes almost complete first-pass metabolism. The reported two active metabolites were not detected in the plasma of any volunteer. Although there is no evidence that the major metabolite has pharmacological activity, the clinical importance of 2-pyridylacetic acid in humans should be reinvestigated.

  18. Relating Pyrolysis GC-MS to Traditional Soil Organic Matter Characterization: a Comparative Study Across a Landscape.

    NASA Astrophysics Data System (ADS)

    Kelleher, J. A.; Carrasco, J. J.; Neff, J. C.

    2004-12-01

    Ecosystem scale soil organic matter studies commonly involve measurements such as physical or chemical separations to bulk soil elemental estimates, however, these measurements provide limited information about SOM structure and how it varies across landscapes. To bridge the gap between molecular-scale and pool-based understanding of SOM dynamics, we compared soil density fractionation and chemical digestion techniques to more detailed pyrolysis GC-MS measurements. Composite soil samples from 0-10 cm were collected from four sites with observably different soil characteristics along the Front Range in Colorado: aspen grove, spruce-fir forest, and alpine dry and wet meadows. Samples were separated into heavy, light, and water fractions (slow, intermediate, and fast SOM turnover pools, respectively) using a 1.8 g/mL density fractionation. Non-polar extractives, polar extractives, cellulose, and lignin abundances were determined using a standard method for organic matter digestion. Significant differences were absent between sites for all density derived components as well as the non-polar and polar extractives. The spruce-fir SOM, however, showed higher % lignin and lower % cellulose compared to all other sites. We measured lignin, polysaccharide, and long-chain aliphatic derivatives using pyrolysis GC-MS and then compared relative abundances using principal component analysis. Spruce-fir SOM was distinguished by the high relative abundance of lignin derivatives that parallels observed higher % lignin by digestion. The dry and wet meadow SOM was distinguished by the relative abundance of long-chain aliphatic compounds. While the density and chemical fractionations were unable to fully distinguish these soils apart, pyrolysis GC-MS provided more detailed information about the chemical composition of SOM across different ecosystems.

  19. Structural studies on the Pseudomonas aeruginosa sialidase-like enzyme PA2794 suggest substrate and mechanistic variations.

    PubMed

    Xu, Guogang; Ryan, Charlotte; Kiefel, Milton J; Wilson, Jennifer C; Taylor, Garry L

    2009-02-27

    Pseudomonas aeruginosa encodes an enzyme (PA2794) that is annotated as a sialidase (or neuraminidase), as it possesses three bacterial neuraminidase repeats that are a signature of nonviral sialidases. A recent report showed that when the gene encoding this sialidase is knocked out, this led to a reduction in biofilm production in the lungs of mice, and it was suggested that the enzyme recognizes pseudaminic acid, a sialic acid analogue that decorates the flagella of Pseudomonas, Helicobacter, and Campylobacter species. Here, we present the crystal structure of the P. aeruginosa enzyme and show that it adopts a trimeric structure, partly held together by an immunoglobulin-like trimerization domain that is C-terminal to a classical beta-propeller sialidase domain. The recombinant enzyme does not show any sialidase activity with the standard fluorogenic sialic-acid-based substrate. The proposed active site contains certain conserved features of a sialidase: a nucleophilic tyrosine with its associated glutamic acid, and two of the usual three arginines that interact with the carboxylic acid group of the substrate, but is missing the first arginine and the aspartic acid that acts as an acid/base in all sialidases studied to date. We show, by in silico docking, that the active site may accommodate pseudaminic acid but not sialic acid and that this is due, in part, to a phenylalanine in the hydrophobic pocket that selects for the alternative stereochemistry of pseudaminic acid at C5 compared to sialic acid. Mutation of this phenylalanine to an alanine converts the enzyme into a sialidase, albeit a poor one, which we confirm by kinetics and NMR, and this allowed us to probe the function of other amino acids. We propose that a histidine plays the role of the acid/base, whose state is altered through a charge-relay system involving a novel His-Tyr-Glu triad. The location of this relay system precludes the presence of one of the three arginines usually found in a sialidase

  20. Sensitive determination of 20(S)-protopanaxadiol in rat plasma using HPLC-APCI-MS: application of pharmacokinetic study in rats.

    PubMed

    Ren, Hong-Can; Sun, Jian-Guo; Wang, Guang-Ji; A, Ji-Ye; Xie, Hai-Tang; Zha, Wei-Bin; Yan, Bei; Sun, Fen-Zhi; Hao, Hai-Ping; Gu, Sheng-Hua; Sheng, Long-Sheng; Shao, Feng; Shi, Jian; Zhou, Fang

    2008-12-15

    20(S)-Protopanaxadiol (PPD), the main metabolite of protopanoxadiol type ginsenosides (e.g. Rg3 and Rh2), is a very promising anti-cancer drug candidate. To evaluate the pharmacokinetic property of PPD, we reported a reliable, sensitive and simple method utilizing liquid chromatography (HPLC)-atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) to determine PPD. PPD and the internal standard, panoxadiol (PD) were extracted from plasma with acetic ether, separated on a C18 reverse column, and then analyzed by APCI-MS. Targeting fragment ion at m/z 425 for both PPD and PD was monitored in selected-ion monitoring (SIM) mode. PPD can be quantitatively determined at the concentration as low as 1 ng/mL using 200 microL plasma. And the sensitive method showed excellent linearity over a range from 1 to 1000 ng/mL, high recovery, accuracy and precision at the concentrations of 2.5, 100.0 and 1000.0 ng/mL, respectively. The method was successfully applied to pharmacokinetic study of PPD in rats. Pharmacokinetic parameters were calculated and absolute bioavailability of PPD was 36.8+/-12.4%, at least ten times higher than that of Rg3 and Rh2, indicating its good absorption in gastrointestinal tract. It was further suggested that PPD be a promising anti-cancer candidate and probably responsible for the observed pharmacological activity of Rg3 and Rh2.

  1. Studies on substantially increased proteins in follicular fluid of bovine ovarian follicular cysts using 2-D PAGE and MALDI-TOF MS

    PubMed Central

    Maniwa, Jiro; Izumi, Shunsuke; Isobe, Naoki; Terada, Takato

    2005-01-01

    Background The objective of this study was to identify substantially increased proteins in bovine cystic follicular fluid (FF) in order to clarify the pathology and etiology of bovine ovarian follicular cysts (BOFC). Methods Proteins in normal and cystic FF samples were subjected to two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and were compared using silver stained gel images with PDQuest image analysis software. Peptides from these increased spots were analyzed by matrix assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), and were identified based on the NCBI database by a peptide mass fingerprinting method. Results Comparative proteomic analysis showed 8 increased protein spots present in cystic FF. MS analysis and database searching revealed that the increased proteins in cystic FF were bovine mitochondrial f1-atpase (BMFA), erythroid associated factor (EAF), methionine synthase (MeS), VEGF-receptor, glyceraldehydes 3-phosphate dehydrogenase (GAPDH), heat shock protein 70 (HSP70), β-lactoglobulin (BLG) and succinate dehydrogenase Ip subunit (SD). Conclusion Our results suggest that these proteins are overexpressed in BOFC, and that they may play important roles in the pathogenesis of BOFC. Furthermore, these proteins in the FF could be useful biomarkers for BOFC. PMID:15941490

  2. Simultaneous determination of corynoline and acetylcorynoline in human urine by LC-MS/MS and its application to a urinary excretion study.

    PubMed

    Liu, Ruijuan; Zheng, Lu; Cheng, Minlu; Wu, Yao; Gu, Pan; Liu, Yujie; Ma, Pengcheng; Ding, Li

    2016-03-01

    Corynoline and acetycorynoline, the major active components derived from Corydalis bungeana Herba, showed multiple pharmacological activities. However, quantification of the two compounds in human urine has not been reported. A simple liquid chromatography with tandem mass spectrometry method for the simultaneous determination of corynoline and acetycorynoline in human urine has been developed and fully validated. The analytes were extracted from urine samples by simple liquid-liquid extraction. Chromatographic separation was achieved on a Hedera ODS-2C18 column with the mobile phase of water (containing 0.5% formic acid) and acetonitrile (28:72, v/v) at a flow rate of 0.4mL/min. A tandem mass spectrometric detection was conducted using multiple reaction monitoring via an electrospray ionization source in positive mode. The monitored ion transitions were m/z 368.1→289.1 for corynoline, m/z 410.2→289.2 for acetycorynoline and m/z 380.2→243.2 for donepezil (internal standard), respectively. The calibration curves were linear (correlation coefficients>0.9970) over the concentration ranges of 3.0-3000pg/mL for corynoline and 3.0-1000pg/mL for acetycorynoline. The established method was highly sensitive with the lower limit of quantification (LLOQ) of 3.0pg/mL for both analytes. The intra- and inter-day precision was lower than 10% in terms of relative standard deviation for the low, medium, and high quality control samples, and lower than 16% for the LLOQ samples of the analytes. The accuracy was within ±10% in terms of relative error for both analytes. The method was successfully applied to a urinary excretion study after oral administration of the Chinese medicine formula Shuanghua Baihe tablets in healthy volunteers. The urinary excretion profiles of corynoline and acetycorynoline in human were first reported. The results of this study suggest that renal excretion was not the main excretion pathway of corynoline and acetycorynoline in humans.

  3. A Corpus-Based System of Error Detection and Revision Suggestion for Spanish Learners in Taiwan: A Case Study

    ERIC Educational Resources Information Center

    Lu, Hui-Chuan; Chu, Yu-Hsin; Chang, Cheng-Yu

    2013-01-01

    Compared with English learners, Spanish learners have fewer resources for automatic error detection and revision and following the current integrative Computer Assisted Language Learning (CALL), we combined corpus-based approach and CALL to create the System of Error Detection and Revision Suggestion (SEDRS) for learning Spanish. Through…

  4. Suggested Guidelines for the Development of Courses of Study in Health Education for Junior and Senior High Schools.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    Both personal and societal aims were cited as the motivating factors for the prototypical, comprehensive health education program outlined here. Cautions and recommendations concerning the program's implementation comprise the introduction. Preliminary material includes a suggested teaching format and a flexible grade placement scheme. The program…

  5. Benzofuran analogues of amphetamine and methamphetamine: studies on the metabolism and toxicological analysis of 5-APB and 5-MAPB in urine and plasma using GC-MS and LC-(HR)-MS(n) techniques.

    PubMed

    Welter, Jessica; Kavanagh, Pierce; Meyer, Markus R; Maurer, Hans H

    2015-02-01

    5-APB (5-(2-aminopropyl)benzofuran) and its N-methyl derivative 5-MAPB (N-methyl-5-(2-aminopropyl)benzofuran) are analogues of amphetamine and methamphetamine, respectively, and belong to the so-called novel psychoactive substances (NPS). They were consumed as stimulants or entactogens with euphoric and empathogenic effects. Being controlled in some countries, both compounds should be covered by drug testing in clinical and forensic toxicology. Therefore, metabolism studies have been performed by working up rat urine samples after a high single dose of the corresponding NPS with solid-phase extraction without and after enzymatic conjugates cleavage. The phase I metabolites were separated and identified after acetylation by GC-MS and/or LC-HR-MS(n) and the phase II metabolites by LC-HR-MS(n). The main metabolite of 5-APB was 3-carboxymethyl-4-hydroxy amphetamine and the main metabolites of 5-MAPB were 5-APB (N-demethyl metabolite) and 3-carboxymethyl-4-hydroxy methamphetamine. The cytochrome P450 (CYP) isoenzymes involved in the 5-MAPB N-demethylation were CYP1A2, CYP2B6, CYP2C19, and CYP2D6, and according to the kinetic parameters, CYP2B6 was responsible for the main part of the total CYP-dependent clearance. An intake of a common users' dose of 5-APB or 5-MAPB could be confirmed in rat urine using the authors' GC-MS and the LC-MS(n) standard urine screening approaches with the corresponding parent drugs as major target. In authentic human urine samples after ingestion of unknown doses of 5-MAPB, both metabolites could also be detected besides the parent drug. The plasma concentrations determined in six clinical cases ranged from 5 to 124 μg/L for 5-MAPB and from 1 to 38 μg/L for its N-demethyl metabolite 5-APB.

  6. Functional magnetic resonance connectivity studies in infants born preterm: suggestions of proximate and long-lasting changes in language organization.

    PubMed

    Kwon, Soo Hyun; Scheinost, Dustin; Vohr, Betty; Lacadie, Cheryl; Schneider, Karen; Dai, Feng; Sze, Gordon; Constable, R Todd; Ment, Laura R

    2016-03-01

    Sophisticated neuroimaging strategies demonstrate alterations in functional connectivity at school age, adolescence, and young adulthood in individuals born preterm. Recent data suggest these alterations are present in the postnatal period prior to term-equivalent age in neonates born preterm. Likewise, functional organization increases across development, but the influence of preterm birth on this fundamental infrastructure is immediate and unchanging. This article briefly reviews the current methods of measuring functional connectivity throughout development in those born preterm, and the association of functional connectivity with language disorders. Taken together, these data suggest that the effects of preterm birth on the functional organization of language in the developing brain are both proximate and long-lasting.

  7. Chemometric study of the influence of instrumental parameters on ESI-MS analyte response using full factorial design

    NASA Astrophysics Data System (ADS)

    Raji, M. A.; Schug, K. A.

    2009-01-01

    Full factorial experimental design technique was used to study the main effects and the interaction effects between instrumental parameters in two mass spectrometers equipped with conventional electrospray ion sources (Thermo LCQ Deca XP and Shimadzu LCMS 2010). Four major parameters (spray voltage, ion transfer capillary temperature, ion transfer capillary voltage, and tube lens voltage) were investigated in both instruments for their contribution to analyte response, leading to a total of 16 experiments performed for each instrument. Significant parameters were identified by plotting the cumulative probability of each treatment against the estimated effects in normal plots. Analysis of variance (ANOVA) was employed to evaluate the statistical significance of the effects of the parameters on ESI-MS analyte response. The results reveal a number of important interactions in addition to the main effects for each instrument. In all the experiments performed, the tube lens voltage (or Q-array dc voltage in LCMS 2010) was found to have significant effects on analyte response in both instruments. The tube lens voltage was also found to interact with the capillary temperature in the case of the LCQ Deca XP and with the spray voltage in the case of the LCMS 2010. The results of these experiments provide important considerations in the instrumental optimization of ionization response for ESI-MS analysis.

  8. Using Hypnotic Suggestion to Model Loss of Control and Awareness of Movements: An Exploratory fMRI Study

    PubMed Central

    Oakley, David A.; Bell, Vaughan; Koppel, Cristina; Mehta, Mitul A.; Halligan, Peter W.

    2013-01-01

    The feeling of voluntary control and awareness of movement is fundamental to our notions of selfhood and responsibility for actions, yet can be lost in neuropsychiatric syndromes (e.g. delusions of control, non-epileptic seizures) and culturally influenced dissociative states (e.g. attributions of spirit possession). The brain processes involved remain poorly understood. We used suggestion and functional magnetic resonance imaging (fMRI) to investigate loss of control and awareness of right hand movements in 15 highly hypnotically suggestible subjects. Loss of perceived control of movements was associated with reduced connectivity between supplementary motor area (SMA) and motor regions. Reduced awareness of involuntary movements was associated with less activation in parietal cortices (BA 7, BA 40) and insula. Collectively these results suggest that the sense of voluntary control of movement may critically depend on the functional coupling of SMA with motor systems, and provide a potential neural basis for the narrowing of awareness reported in pathological and culturally influenced dissociative phenomena. PMID:24205198

  9. Oxidation of danofloxacin by free chlorine-kinetic study, structural identification of by-products by LC-MS/MS and potential toxicity of by-products using in silico test.

    PubMed

    Yassine, Montaha; Rifai, Ahmad; Doumyati, Samah; Trivella, Aurélien; Mazellier, Patrick; Budzinski, Hélène; Al Iskandarani, Mohamad

    2017-01-20

    In this study, we aimed to investigate the kinetics and the mechanism of reaction of the fluoroquinolone antibacterial danofloxacin (DANO) by free available chlorine (FAC) during water chlorination process. Kinetic study was thus performed at pH 7.2, 20 °C in the presence of an excess of total chlorine. Under these experimental conditions, a second-order reaction rate constant (first-order relative to DANO concentration and first-order relative to FAC concentration) was evaluated to k~1446 M(-1) s(-1). Five degradation products were identified at different reaction times. Their structures were investigated by using fragmentations obtained at different CID collision energies in MS/MS experiments. Moreover, the toxicity of the proposed structures was predicted by using T.E.S.T.

  10. Single-laboratory validation of an LC-MS/MS method for determining florfenicol (FF) and florfenicol amine (FFA) residues in chicken feathers and application to a residue-depletion study.

    PubMed

    Cornejo, J; Pokrant, E; Riquelme, R; Briceño, C; Maddaleno, A; Araya-Jordán, C; San Martin, B

    2017-04-01

    A suitable analytical method is required to study the behaviour of florfenicol (FF) and its metabolite florfenicol amine (FFA) in broiler's feathers. An LC-MS/MS method was developed, assessed and intra-laboratory-validated for FF and FFA analyses. We chose cloramphenicol-d5 as an internal standard, acetone as a solvent for the extraction of the analytes and dichloromethane for the clean-up. Through LC-MS/MS analysis, we established a detection limit of 20 μg kg(-)(1), as well as calculated quantification limits of 24.4 and 24.5 μg kg(-)(1) for FF and FFA, respectively. Validation parameters such as linearity, recovery and precision were calculated following Commission Decision 2002/657/EC. For linearity, all standard curves showed a standard coefficient greater than 0.99. Recoveries ranged from 99% to 102% for all studied concentrations. The results show that this analytical method is precise and reliable. For the depletion study, 64 Ross 308 broilers were treated with a therapeutic dosage of 10% FF during 5 consecutive days and their feathers were then analysed. Samples were drawn on days 5, 10, 15, 20, 25, 30, 35 and 40 post-treatments. As for the control group, 16 broiler chickens were raised under the same regime. Throughout the whole study, the detected concentrations of FF and FFA in feather samples were above 100 µg kg(-)(1). In fact, even on day 30 post-treatment we detected concentrations of 221.8 and 28.8 µg kg(-)(1) for FF and FFA, respectively. Based on these results, we conclude that these analytes will persist for a long time and will deplete slowly in feathers of treated broiler chickens.

  11. Development and utilization of a combined LC-UV and LC-MS/MS method for the simultaneous analysis of tegafur and 5-fluorouracil in human plasma to support a phase I clinical study of oral UFT®/leucovorin.

    PubMed

    Peer, Cody J; McManus, Terence J; Hurwitz, Herbert I; Petros, William P

    2012-06-01

    Tegafur is a 5-fluorouracil (5-FU) prodrug widely used outside the United States to treat colorectal cancer as well as cancers of the head and neck. The resulting plasma concentrations of tegafur are much higher than those of 5-FU; thus, analytical methods are needed that are sensitive enough to detect low plasma concentrations of 5-FU and robust enough to simultaneously analyze tegafur. Previous LC-MS/MS methods have either failed to demonstrate the ability to simultaneously measure low 5-FU and high tegafur plasma levels, or failed to be applicable in clinical studies. Our goal was to develop a method capable of measuring low concentrations of 5-FU (8-200 ng/ml) and high concentrations of tegafur (800-20,000 ng/ml) in human plasma and to subsequently evaluate the utility of the method in patient samples collected during a phase I clinical study where oral doses of either 200mg or 300 mg UF®/LV (uracil and tegafur in a 4:1 molar ratio plus leucovorin) were administered. A combined LC-MS/MS and LC-UV method was developed utilizing negative ion atmospheric pressure ionization (API). The method provides an accuracy and precision of <10% and <6%, respectively, for both analytes. Material recoveries from the liquid-liquid extraction technique were 97-110% and 86-91% for tegafur and 5-FU, respectively. Utilization of this method to determine tegafur and 5-FU plasma concentrations followed by noncompartmental pharmacokinetic analyses successfully estimated pharmacokinetic parameters (C(MAX), t(MAX) and AUC(0-10h)) in the clinical study patients. Overall, this method is ideal for the simultaneous bioanalysis of low levels of 5-FU and relatively higher levels of its prodrug, tegafur, in human plasma for clinical pharmacokinetic analysis.

  12. Comparative pharmacokinetic studies of peimine and peiminine in rat plasma by LC-MS-MS after oral administration of Fritillaria thunbergii Miq. and Fritillaria thunbergii Miq. - Glycyrrhiza uralensis Fisch. couple extract.

    PubMed

    Chen, Lihua; Liu, Lili; Zhu, Weifeng; Zhang, Huimin; Yan, Zhihong; Liu, Hongning

    2011-09-01

    A sensitive LC-MS-MS method has been successfully applied to pharmacokinetic study of peimine and peiminine in rat plasma after oral administration of Fritillaria thunbergii Miq. exact and Fritillaria thunbergii Miq. - Glycyrrhiza uralensis Fisch. couple extract. The results indicated that plasma profiles of peimine and peiminine confirmed to two-compartment open model with weighting function of 1/C2 for data fitting and parameter estimation and the utilization with Glycyrrhiza uralensis Fisch. could decrease C(max) and prolong MRT(0-infinity) and t1/2 of peimine remarkly with the bioavailability of peimine remained practically unchanged. Meanwhile, the concentration of peimine in rat plasma was more stable. Nevertheless, there were no significant differences among all calculated parameters of peiminine.

  13. Childhood and Adolescent Sexual Abuse and Subsequent Sexual Risk Behavior: Evidence from Controlled Studies, Methodological Critique, and Suggestions for Research

    PubMed Central

    Senn, Theresa E.; Carey, Michael P.; Vanable, Peter A.

    2008-01-01

    Childhood and adolescent sexual abuse (CSA) is associated with a wide variety of adverse psychological and health outcomes, including negative sexual health outcomes. In this paper, we review the literature investigating the relation between CSA and subsequent sexual risk behaviors among men and women. Previous research has found a relatively consistent association between CSA and higher rates of sexual risk behaviors, particularly sex trading, more sexual partners, and an earlier age of first intercourse. However, there are a number of limitations to this research, including lack of a consistent definition of CSA, failure to investigate gender as a moderator, and possible confounding of the CSA experience with some of the sexual behavior outcome variables. Further, although there appears to be an association between CSA and later sexual risk behavior, researchers have not established whether this association is causal. Suggestions for future research and implications for clinical practice are discussed. PMID:18045760

  14. Bioanalytical assay development and validation for simultaneous quantification of five schisandra lignans in rat primary hepatocytes based on LC-MS/MS: application to a real-time uptake study for Schisandra Lignan Extract.

    PubMed

    Kang, Dian; Shao, Yuhao; Yin, Xiaoxi; Xiao, Jingcheng; Rao, Tai; Shen, Boyu; Chen, Huimin; Zhu, Zhangpei; Wang, Guangji; Liang, Yan

    2017-02-01

    Schisandra lignans, mainly including schizandrol A, schizandrol B, schisantherin A, schizandrin A, schizandrin B, etc., are the major active ingredients of Schisandra chinensis. In the present study, a robust liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the simultaneous quantification of schisandra lignans in rat primary hepatocytes. Lovastatin was used as an internal standard, and chromatographic separation was achieved on a Shimadzu C18 column with a gradient elution at the flow rate of 0.2 mL/min. All of the analytes were detected in multiple reaction monitoring mode with positive electrospray ionization since the sodium adduct ion [M + Na](+) was observed as the most intensive peak in the MS spectrum. For schizandrol A, schisantherin A and schizandrin A, the dynamic range was within 2-1000 ng/mg protein, and the linear range of schizandrol B and schizandrin B was from 5 to 1000 ng/mg protein. The intra- and inter-day precision was <15% and the accuracy (relative error) ranged from -15 to 15%. No significant variation was observed in the stability tests. The validated method was then successfully applied to the time-dependent uptake study for the Schisandra Lignan Extract in rat primary hepatocytes.

  15. A Multi-Center Controlled Study of the Acute and Chronic Effects of Cooling Therapy for MS

    NASA Technical Reports Server (NTRS)

    Luna, Bernadette; Schwid, Steven W.; Cutter, Gary; Murray, Ronald; Bowen, James; Pellegrino, Richard; Guisado, Raul; Webbon, Bruce W.; DeVincenzi, Donald (Technical Monitor)

    2000-01-01

    To determine the acute and chronic effects of cooling therapy on patients with MS using objective functional performance measures and self-assessed measures of fatigue. Cooling demyelinated nerves can reduce conduction block, potentially improving symptoms of MS. Significant acute and chronic effects of cooling have not been demonstrated in a multi-center, controlled, blinded study using objective measures of neurologic function. Patients (N=84) with definite MS, mild to moderate disability (EDSS less than 6.0), and self-reported heat sensitivity were enrolled at 5 study sites. Acute effects of cooling were assessed by randomly assigning subjects to high-dose or low-dose cooling for one hour using an active cooling vest and cap (Life Enhancement Technologies, Santa Clara, CA). Settings were individualized to maintain the cooling garments at 55 F for the high-dose treatment and 70 F for the low-dose treatment. Both patients and examining investigators were blinded to treatment assignments. The MSFC and visual acuity/contrast sensitivity were assessed before and 30 minutes after treatment. The following week, subjects had an identical visit with the alternate cooling treatment. Chronic effects of cooling were assessed by randomly assigning the same subjects to unblinded daily home cooling or observation for 4 weeks. All subjects completed the Rochester Fatigue Diary (RFD) twice weekly and subjective measures of strength, cognition, and energy level daily. At the end of the period, subjects completed the Modified Fatigue Impact Scale (MFIS) and underwent another high-dose cooling session with assessment of the MSFC and vision. After a one-week washout period, subjects crossed over to the alternate 4-week treatment. Oral temperatures were reduced with both acute treatments (0.8 +/- .06 F, high and 0.5 +/- .06 F, low). While mean MSFC did not change significantly during individual cooling sessions, post hoc analysis pooling the 3 high-dose cooling sessions revealed an

  16. Study of organic compounds evolved during the co-firing of coal and refuse derived fuel using TG/MS

    SciTech Connect

    Puroshothama, Shobha; Lu, R.; Yang, Xiaodong

    1996-10-01

    The evolution of organic compounds during the combustion of carbonaceous fuel coupled with solid waste disposal and limited landfill space has been a cause for concern. Co-firing high sulfur coal with refuse derived fuel seems an attractive alternative technique to tackle the dual problem of controlling SO{sub x} emissions as well as those of the chlorinated organic toxins. The TG serves to emulate the conditions of the fluidized bed combustor and the MS serves as the detector for evolved gases. This versatile combination is used to study the decomposition pathway as well as predict the conditions at which various compounds are formed and may serve as a means of reducing the formation of these chlorinated organic compounds.

  17. Genome-environment association study suggests local adaptation to climate at the regional scale in Fagus sylvatica.

    PubMed

    Pluess, Andrea R; Frank, Aline; Heiri, Caroline; Lalagüe, Hadrien; Vendramin, Giovanni G; Oddou-Muratorio, Sylvie

    2016-04-01

    The evolutionary potential of long-lived species, such as forest trees, is fundamental for their local persistence under climate change (CC). Genome-environment association (GEA) analyses reveal if species in heterogeneous environments at the regional scale are under differential selection resulting in populations with potential preadaptation to CC within this area. In 79 natural Fagus sylvatica populations, neutral genetic patterns were characterized using 12 simple sequence repeat (SSR) markers, and genomic variation (144 single nucleotide polymorphisms (SNPs) out of 52 candidate genes) was related to 87 environmental predictors in the latent factor mixed model, logistic regressions and isolation by distance/environmental (IBD/IBE) tests. SSR diversity revealed relatedness at up to 150 m intertree distance but an absence of large-scale spatial genetic structure and IBE. In the GEA analyses, 16 SNPs in 10 genes responded to one or several environmental predictors and IBE, corrected for IBD, was confirmed. The GEA often reflected the proposed gene functions, including indications for adaptation to water availability and temperature. Genomic divergence and the lack of large-scale neutral genetic patterns suggest that gene flow allows the spread of advantageous alleles in adaptive genes. Thereby, adaptation processes are likely to take place in species occurring in heterogeneous environments, which might reduce their regional extinction risk under CC.

  18. A brief, critical review of research on impaired control over alcohol use and suggestions for future studies.

    PubMed

    Leeman, Robert F; Beseler, Cheryl L; Helms, Christa M; Patock-Peckham, Julie A; Wakeling, Vanessa A; Kahler, Christopher W

    2014-02-01

    Impaired control, defined as "a breakdown of an intention to limit consumption" (Heather et al. J Stud Alcohol 1993; 54, 701), has historically been considered an important aspect of addiction. Despite recognition of its importance to addiction and potential value as an early indicator of problem drinking risk, we argue that impaired control over alcohol use has not received sufficient research attention. In an effort to spark further research, the present critical review offers brief discussion of the current state of knowledge regarding impaired control and avenues for future research. Three main research areas are addressed: (i) epidemiology; (ii) measurement issues; and (iii) potential mechanisms underlying relationships between impaired control and subsequent problem drinking. Measurement issues include complexities involved in self-report assessment of impaired control, development and validation of human and animal laboratory models, and impaired control's relationship to other constructs (i.e., impulsivity and other difficulties with self-control; symptoms of dependence such as craving). We discuss briefly 2 potential mechanisms that may help to explain why some drinkers experience impaired control while others do not: neurobiological dysfunction and family history/genetics. Suggestions for future research are focused on ways in which the impaired control construct may enhance prediction of who might be at particular risk of subsequent problem drinking and to facilitate intervention to reduce problem alcohol use.

  19. Studies of Peptide:N-glycnase-p97 Interaction Suggest that p97 Phosphorylation Modulates Endoplasmic Reticulum-Associated Degradation

    SciTech Connect

    Zhao,G.; Zhou, X.; Wang, L.; Li, G.; Schindelin, H.; Lennarz, W.

    2007-01-01

    During endoplasmic reticulum-associated degradation, the multifunctional AAA ATPase p97 is part of a protein degradation complex. p97 associates via its N-terminal domain with various cofactors to recruit ubiquitinated substrates. It also interacts with alternative substrate-processing cofactors, such as Ufd2, Ufd3, and peptide:N-glycanase (PNGase) in higher eukaryotes. These cofactors determine different fates of the substrates and they all bind outside of the N-terminal domain of p97. Here, we describe a cofactor-binding motif of p97 contained within the last 10 amino acid residues of the C terminus, which is both necessary and sufficient to mediate interactions of p97 with PNGase and Ufd3. The crystal structure of the N-terminal domain of PNGase in complex with this motif provides detailed insight into the interaction between p97 and its substrate-processing cofactors. Phosphorylation of p97's highly conserved penultimate tyrosine residue, which is the main phosphorylation site during T cell receptor stimulation, completely blocks binding of either PNGase or Ufd3 to p97. This observation suggests that phosphorylation of this residue modulates endoplasmic reticulum-associated protein degradation activity by discharging substrate-processing cofactors.

  20. A Brief, Critical Review of Research on Impaired Control over Alcohol Use and Suggestions for Future Studies

    PubMed Central

    Leeman, Robert F.; Beseler, Cheryl L.; Helms, Christa M.; Patock-Peckham, Julie A.; Wakeling, Vanessa A.; Kahler, Christopher W.

    2013-01-01

    Impaired control, defined as “a breakdown of an intention to limit consumption” (Heather et al. 1993; p. 701) has historically been considered an important aspect of addiction. Despite recognition of its importance to addiction and potential value as an early indicator of problem drinking risk, we argue that impaired control over alcohol use has not received sufficient research attention. In an effort to spark further research, the present critical review offers brief discussion of the current state of knowledge regarding impaired control and avenues for future research. Three main research areas are addressed: 1) epidemiology, 2) measurement issues and 3) potential mechanisms underlying relationships between impaired control and subsequent problem drinking. Measurement issues include complexities involved in self-report assessment of impaired control, development and validation of human and animal laboratory models, and impaired control’s relationship to other constructs (i.e., impulsivity and other difficulties with self-control; symptoms of dependence such as craving). We discuss briefly two potential mechanisms that may help to explain why some drinkers experience impaired control while others do not: neurobiological dysfunction and family history/genetics. Suggestions for future research are focused on ways in which the impaired control construct may enhance prediction of who might be at particular risk of subsequent problem drinking and to facilitate intervention to reduce problem alcohol use. PMID:24117468

  1. Nursing student descriptions that suggest changes for the classroom and reveal improvements needed in study skills and self-care.

    PubMed

    Gardner, Elaine A; Deloney, Linda A; Grando, Victoria T

    2007-01-01

    This article describes a longitudinal study that took place in a college of nursing with baccalaureate students between 2002 and 2004 at a university medical center. Its purpose was to provide a climate of success for the students yet challenge them to make additional efforts to complete the program. The qualitative section of the study consisted of students answering the following open-ended questions: (1) Describe ways that faculty can help you be successful in the future and (2) What can you do for yourself to achieve the goal of finishing the program? Students identified what change could be made in the classroom, how increased study time and skills might help, and how self-care would facilitate success. Descriptions were shared with faculty and students in an effort to improve classroom delivery, provide study tips to students, and help students become aware of increased self-care. Students as future nurses, enter practice and care for patients who will need the best care and self-care instruction. Using techniques that students identified to be successful, making efforts through hard work (increased study skills), and realizing how to better care for themselves could assist RNs in providing comprehensive and best care to patients.

  2. A study of turbulence near thunderstorm tops. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Pantley, Kim Christine

    1989-01-01

    It has been known for many years that turbulence significant for aviation often occurs near thunderstorm tops. However, that turbulence is not well-predicted because of an incomplete understanding of the processes which generate it and because of inadequate observations. The current study seeks to alleviate these problems via: (1) a comprehensive review of recent theoretical and experimental studies related to turbulence near thunderstorm tops (TNTT), and (2) three case studies designed to examine the feasibility of using data derived from commercial aircraft to study TNTT. The literature review revealed extensive evidence which showed that convection often produces significant barrier effects; several mesoscale phenomena capable of producing turbulence may occur, depending on wind and stability conditions near the thunderstorm tops. These include two- and three-dimensional lee waves, rotors, Kelvin-Helmholtz instabilities, and Karman vortices. Conventional meteorological data were combined with data derived from the aircraft flight tapes to produce quantitative descriptions of the turbulence and its mesoscale environment for the three cases.

  3. Case studies: the impact of nonanalyte components on LC-MS/MS-based bioanalysis: strategies for identifying and overcoming matrix effects.

    PubMed

    Li, Fumin; Ewles, Matthew; Pelzer, Mary; Brus, Theodore; Ledvina, Aaron; Gray, Nicholas; Koupaei-Abyazani, Mohammad; Blackburn, Michael

    2013-10-01

    Achieving sufficient selectivity in bioanalysis is critical to ensure accurate quantitation of drugs and metabolites in biological matrices. Matrix effects most classically refer to modification of ionization efficiency of an analyte in the presence of matrix components. However, nonanalyte or matrix components present in samples can adversely impact the performance of a bioanalytical method and are broadly considered as matrix effects. For the current manuscript, we expand the scope to include matrix elements that contribute to isobaric interference and measurement bias. These three categories of matrix effects are illustrated with real examples encountered. The causes, symptoms, and suggested strategies and resolutions for each form of matrix effects are discussed. Each case is presented in the format of situation/action/result to facilitate reading.

  4. A Study of the Presence of Gunshot Residue in Pittsburgh Police Stations using SEM/EDS and LC-MS/MS.

    PubMed

    Ali, Leah; Brown, Kyle; Castellano, Holly; Wetzel, Stephanie J

    2016-07-01

    Due to possible secondary transfer of gunshot residue (GSR) onto a suspect in police custody prior to sampling, a baseline must be created for the amount of GSR present. With an increase of "lead free" ammunition, testing for both gunpowder and primer GSR is relevant. Seventy samples were collected using carbon-coated adhesive stubs from four Pittsburgh Police Stations and vehicles to investigate these locations as sources of secondary GSR contamination. These seventy samples were analyzed for primer GSR using scanning electron microscopy-energy-dispersive X-ray spectrometry. One primer GSR particle was detected; no sample was classified as positive for primer GSR. These same samples were then analyzed for gunpowder GSR using liquid chromatography coupled to tandem mass spectrometry to test for akardite II, ethylcentralite, diphenylamine, N-nitrosodiphenylamine, 2-nitrodiphenylamine, and 4-nitrodiphenylamine. Ethylcentralite was quantifiable in two test samples. These results suggest there is a negligible potential for secondary transfer of primer and gunpowder GSR.

  5. A comparative study of ballpoint ink ageing parameters using GC/MS.

    PubMed

    Koenig, Agnès; Magnolon, Sophie; Weyermann, Céline

    2015-07-01

    For more than a decade scientists tried to develop methods capable of dating ink by monitoring the loss of phenoxyethanol (PE) over time. While many methods were proposed in the literature, few were really used to solve practical cases and they still raise much concern within the scientific community. In fact, due to the complexity of ink drying processes it is particularly difficult to find a reliable ageing parameter to reproducibly follow ink ageing. Moreover, systematic experiments are required in order to evaluate how different factors actually influence the results over time. Therefore, this work aimed at evaluating the capacity of four different ageing parameters to reliably follow ink ageing over time: (1) the quantity of solvent PE in an ink line, (2) the relative peak area (RPA) normalising the PE results using stable volatile compounds present in the ink formulation, (3) the solvent loss ratio (R%) calculated from PE results obtained by the analyses of naturally and artificially aged samples, (4) a modified solvent loss ratio version (R%*) calculated from RPA results. After the determination of the limits of reliable measurements of the analytical method, the repeatability of the different ageing parameters was evaluated over time, as well as the influence of ink composition, writing pressure and storage conditions on the results. Surprisingly, our results showed that R% was not the most reliable parameter, as it showed the highest standard deviation. Discussion of the results in an ink dating perspective suggests that other proposed parameters, such as RPA values, may be more adequate to follow ink ageing over time.

  6. CIVIL AND HIGHWAY TECHNOLOGY, SUGGESTED TECHNIQUES FOR DETERMINING COURSES OF STUDY IN VOCATIONAL-TECHNICAL EDUCATION PROGRAMS.

    ERIC Educational Resources Information Center

    PETERSON, CLARENCE E.

    THE PURPOSE OF THIS REPORT IS TO EXPLAIN HOW BASIC OCCUPATIONAL INFORMATION FROM A JOB ANALYSIS IS USED TO SHOW THE RELATIONSHIPS AMONG JOBS AND TO ESTABLISH COURSES OF STUDY FOR OCCUPATIONAL EDUCATION. IT WAS DEVELOPED UNDER TITLE VIII OF THE NATIONAL DEFENSE EDUCATION ACT OF 1958. TOPICS COVERED ARE THE FIELD OF WORK, JOB RELATIONSHIPS, JOB…

  7. Development of a UFLC-MS/MS method for simultaneous determination of six lignans of Schisandra chinensis (Turcz.) Baill. in rat plasma and its application to a comparative pharmacokinetic study in normal and insomnic rats.

    PubMed

    Wei, Binbin; Li, Qing; Su, Dan; Fan, Ronghua; Zhao, Longshan; Geng, Lulu; He, Bosai; Chen, Xiaohui; Jia, Ying; Bi, Kaishun

    2013-04-15

    Schisandra chinensis (Turcz.) Baill., a traditional Chinese medicine, has been used for treating insomnia for centuries. This paper was designed to study on the plasma pharmacokinetic for its absorption process, and to compare the pharmacokinetics of its active ingredients in normal and insomnic rats orally administrated with the prescription. Therefore, an efficient, sensitive and selective ultra fast liquid chromatography/tandem mass spectrometry (UFLC-MS/MS) method for the simultaneous determination of six sedative and hypnotic lignans (schisandrin, schisandrol B, schisantherin A, deoxyshisandrin, γ-schisandrin and gomisin N) of Schisandra chinensis (Turcz.) Baill. in rat plasma has been developed and validated. The analysis was performed on a Shim-pack XR-ODS column (75mm×3.0mm, 2.2μm) using gradient elution with the mobile phase consisting of acetonitrile and 0.1% formic acid waterat a flow rate of 0.4ml/min. The detection of the analytes was performed on 4000Q UFLC-MS/MS system with turbo ion spray source in the positive ion and multiple reaction-monitoring mode. The method was validated in plasma samples, which showed good linearity over a wide concentration range (r(2)>0.99), and obtained lower limits of quantification were 10, 1.2, 1.2, 1.2, 1.0 and 1.2ngmL(-1) for the analytes. The intra- and inter-day assay variability was less than 15% for all analytes. The mean extraction recoveries of analytes and IS from rats plasma were all more than 85.0%. The validated method has been successfully applied to comparing pharmacokinetic profiles of analytes in rat plasma. The results indicated that significant difference in pharmacokinetic parameters of the analytes was observed between two groups, while absorptions of these analytes in insomnic group were all significantly higher than those in normal group.

  8. A UPLC-MS/MS method for simultaneous quantitation of three monoterpene glycosides and four alkaloids in rat plasma: application to a comparative pharmacokinetic study of Huo Luo Xiao Ling Dan and single herb extract.

    PubMed

    Ai, Yu; Wu, Yun; Wang, Fenrong; Ma, Wen; Bian, Qiaoxia; Lee, David Y-W; Dai, Ronghua

    2015-03-01

    The objective of this study was to develop a sensitive and reliable ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous quantitation of three monoterpene glycosides (paeoniflorin, alibiflorin and oxypaeoniflorin) and four alkaloids (tetrahydropalmatine, corydaline, dehydrocorydaline and berberine), the main active ingredients of Radix Paeoniae Rubra extract (RPE) and Corydalis yanhusuo extract (CYE) in Huo Luo Xiao Ling Dan (HLXLD), and to compare the pharmacokinetics of these active ingredients in normal and arthritic rats orally administrated with HLXLD or RPE/CYE alone. The analytes and internal standard (IS) (geniposide) were separated on a XBridge C18 column (150 × 4.6 mm, 3.5 µm) using gradient elution with the mobile phase consisting of methanol and 0.01% formic acid in water at a flow rate of 0.6 ml/min. The detection of the analytes was performed on Acquity UPLC-MS/MS system with an electrospray ionization and multiple reaction monitoring mode via polarity switching between negative (for monoterpene glycosides) and positive (for alkaloids) ionization mode. The lower limits of quantification were 2.5, 1, 0.5, 0.2, 0.2, 0.02 and 0.01 ng/ml for paeoniflorin, alibiflorin, oxypaeoniflorin, tetrahydropalmatine, corydaline, dehydrocorydaline and berberine, respectively. Intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (15%). The mean extraction recoveries of analytes and IS from rat plasma were all more than 83.1%. The validated method has been successfully applied to determination of the analytes. Results showed that there were remarkable differences in pharmacokinetic properties of the analytes between herbal formula and single herb group, normal and arthritic group.

  9. A validated enantioselective LC-MS/MS assay for quantification of a major chiral metabolite of an achiral 11-β-hydroxysteroid-dehydrogenase 1 inhibitor in human plasma: Application to a clinical pharmacokinetic study.

    PubMed

    Furlong, Michael T; Ji, Qin C; Iacono, Lisa; Dang, Oanh; Noren, Marzena; Bruce, John; Aubry, Anne-Françoise; Arnold, Mark E

    2016-06-01

    BMS-823778 is a potent 11-β-hydroxysteroid-dehydrogenase 1 (11βHSD-1) inhibitor and a potential therapeutic agent for type 2 diabetes mellitus (T2DM). A high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed and validated to enable reliable separation and quantification of both enantiomers of a chiral hydroxy metabolite (BMT-094817) in human plasma. Following liquid-liquid extraction in a 96-well plate format, chromatographic separation of the metabolite enantiomers was achieved by isocratic elution on a Chiralpak IA-3 column. Chromatographic conditions were optimized to ensure separation of both metabolite enantiomers. Metabolite enantiomers and stable isotope-labeled (SIL) internal standards were detected by positive ion electrospray tandem mass spectrometry. The LC-MS/MS assay was validated over a concentration range of 0.200-200ng/mL. Intra- and inter-assay precision values for replicate quality control samples were less than 9.9% for both enantiomers during the assay validation. Mean quality control accuracy values were within ±7.3%. Assay recoveries were high (>75%) and consistent across the assay range. The metabolite enantiomers were stable in human blood for 2h on ice. The analytes were also stable in human plasma for 25h at room temperature, 34days at -20°C and -70°C, and following five freeze-thaw cycles. No interconversion of the metabolite enantiomers was detected under any bioanalytical stress conditions, from blood collection/processing through extracted sample storage. The validated assay was successfully applied to the quantification of both metabolite enantiomers in human plasma in support of a human pharmacokinetic study.

  10. Scanning electron microscopy study of adhesion in sea urchin blastulae. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Crowther, Susan D.

    1988-01-01

    The dissociation supernatant (DS) isolated by disaggregating Strongylocentrotus purpuratus blastulae in calcium- and magnesium-free seawater specifically promotes reaggregation of S. purpuratus blastula cells. The purpose of this study was to use scanning electron microscopy to examine the gross morphology of aggregates formed in the presence of DS to see if it resembles adhesion in partially dissociated blastulae. A new reaggregation procedure developed here, using large volumes of cell suspension and a large diameter of rotation, was utilized to obtain sufficient quantities of aggregates for scanning electron microscopy. The results indicate that aggregates formed in the presence of DS resemble partially dissociated intact embryos in terms of the direct cell-cell adhesion observed. DS did not cause aggregation to form as a result of the entrapment of cells in masses of extracellular material. These studies provide the groundwork for further studies using transmission electron microscopy to more precisely define the adhesive contacts made by cells in the presence of the putative adhesion molecules present in DS.

  11. A phylogeny of the Tylototriton asperrimus group (Caudata: Salamandridae) based on a mitochondrial study: suggestions for a taxonomic revision.

    PubMed

    Yuan, Zhi-Yong; Jiang, Ke; Lü, Shun-Qing; Yang, Jun-Xiao; Nguyen, Quang Truong; Nguyen, Thien Tao; Jin, Jie-Qiong; Che, Jing

    2011-12-01

    A phylogenetic hypothesis for the Asian newts of the Tylototriton asperrimus group was generated using data from two mitochondrial fragments including COI and the ND1-ND2 regions. Four distinct clades (A, B, C, D) were resolved with high nodal support within this monophyletic group. Clade A included T. asperrimus, T. hainanensis, T. notialis, "T. vietnamensis", and two unnamed salamander populations from Vietnam. Clade A, constituted the sister group of clades B + C. Newly identified clade C likely represents a new cryptic species. Clade C was the sister group of T. wenxianensis. The true T. vietnamensis exclusively constituted clade D. Our results bring into question some previous taxonomic decisions, and a revision is required. This study illustrates the necessity to include samples from type localities in taxonomic studies, and highlights the importance of fine-grained geographical sampling.

  12. Challenges in current adult fish laboratory reproductive tests: suggestions for refinement using a mummichog (Fundulus heteroclitus) case study.

    PubMed

    Bosker, Thijs; Munkittrick, Kelly R; MacLatchy, Deborah L

    2009-11-01

    Concerns about screening endocrine-active contaminants have led to the development of a number of short-term fish reproductive tests. A review conducted of 62 published adult fish reproductive papers using various fish species found low samples sizes (mean of 5.7 replicates with a median of 5 replicates) and high variance (an average coefficient of variance of 43.8%). The high variances and low sample sizes allow only relatively large differences to be detected with the current protocols; the average significant difference detected was a 68.7% reduction in egg production, while only differences above 50% were detected with confidence. This result indicates low power to detect more subtle differences and a high probability of type II errors in interpretation. The present study identifies several ways to increase the power of the adult fish reproductive test in the mummichog (Fundulus heteroclitus). By identifying the peak timing of egg production (before and after the new moon), extending the duration of the experiment (increased from 7 to 14 d), and determining that a sample size of eight replicate tanks per treatment accurately predicts variance in the sample population (based on pre-exposure variation calculations of replicate tanks), the power of the test has been significantly increased. The present study demonstrates that weaknesses in the current adult fish reproductive tests can easily be addressed by focusing on improved understanding of the reproductive behavior of the test species and developing study designs that include calculating desired variability levels and increasing replicates.

  13. Predictors of diagnostic neuroimaging delays among adults presenting with symptoms suggestive of acute stroke in Ontario: a prospective cohort study

    PubMed Central

    Burton, Kirsteen R.; Kapral, Moira K.; Li, Shudong; Fang, Jiming; Moody, Alan R.; Krahn, Murray; Laupacis, Andreas

    2016-01-01

    Background: Many studies have examined the timeliness of thrombolysis for acute ischemic stroke, but less is known about door-to-imaging time. We conducted a prospective cohort study to assess the timing of neuroimaging among patients with suspected acute stroke in the province of Ontario, Canada, and to examine factors associated with delays in neuroimaging. Methods: We included all patients 18 years and older with suspected acute stroke seen at hospitals with neuroimaging capacity within the Ontario Stroke Registry between Apr. 1, 2010, and Mar. 31, 2011. We used a hierarchical, multivariable Cox proportional hazards model to evaluate the association between patient and hospital factors and the likelihood of receiving timely neuroimaging (≤ 25 min) after arrival in the emergency department. Results: A total of 13 250 patients presented to an emergency department with stroke-like symptoms during the study period. Of the 3984 who arrived within 4 hours after symptom onset, 1087 (27.3%) had timely neuroimaging. The factors independently associated with an increased likelihood of timely neuroimaging were less time from symptom onset to presentation, more severe stroke, male sex, no history of stroke or transient ischemic attack, arrival to hospital from a setting other than home and presentation to a designated stroke centre or an urban hospital. Interpretation: A minority of patients with stroke-like symptoms who presented within the 4-hour thrombolytic treatment window received timely neuroimaging. Neuroimaging delays were influenced by various patient and hospital factors, some of which are modifiable. PMID:27398382

  14. Seroprevalence of Alphavirus Antibodies in a Cross-Sectional Study in Southwestern Tanzania Suggests Endemic Circulation of Chikungunya

    PubMed Central

    Dobler, Gerhard; Saathoff, Elmar; Kroidl, Inge; Ntinginya, Nyanda Elias; Maboko, Leonard; Löscher, Thomas; Hoelscher, Michael; Heinrich, Norbert

    2014-01-01

    Background To date, Alphavirus infections and their most prominent member, chikungunya fever, a viral disease which first became apparent in Tanzania in 1953, have been very little investigated in regions without epidemic occurrence. Few data exist on burden of disease and socio-economic and environmental covariates disposing to infection. Methods A cross-sectional seroprevalence study was undertaken in 1,215 persons from Mbeya region, South-Western Tanzania, to determine the seroprevalence of anti-Alphavirus IgG antibodies, and to investigate associated risk factors. Results 18% of 1,215 samples were positive for Alphavirus IgG. Seropositivity was associated with participant age, low to intermediate elevation, flat terrain and with IgG positivity for Rift Valley fever, Flaviviridae, and rickettsiae of the spotted fever group. When comparing the geographical distribution of Alphavirus seropositivity to that of Rift Valley fever, it was obvious that Alphaviruses had spread more widely throughout the study area, while Rift Valley fever was concentrated along the shore of Lake Malawi. Conclusion Alphavirus infections may contribute significantly to the febrile disease burden in the study area, and are associated with several arthropod-borne infections. Their spread seems only limited by factors affecting mosquitoes, and seems less restricted than that of Rift Valley fever. PMID:25079964

  15. CAM Use and Suggestions for Medical Care of Senior Citizens: A Qualitative Study Using the World Café Method

    PubMed Central

    Stöckigt, B.; Teut, M.; Witt, C. M.

    2013-01-01

    Background. Little data exists concerning the reasons for using complementary and alternative (CAM) therapies by seniors. Therefore, the aim of this study is to learn about motives of German seniors for using CAM therapies and their wishes for health care in general. Methods. One focus group and one “World Café” following a semistructured interview guide were conducted. All discussions were recorded digitally, transcribed, and analyzed according to Qualitative Content Analysis using the software MAXQDA. Results. In total 21 seniors participated (eighteen female, three male, mean age 72.5 ± 4.3 years). Most of the participants had lifelong experiences with medicinal herbs and home remedies due to unavailable conventional care during childhood. Also important for them were nutrition and exercise. These methods were often used as self-care to enhance wellbeing, to prevent and to cure illnesses. The participants would welcome an integration of CAM in health care services. They asked especially for more empathic physicians who are better trained in CAM and respect their experiences. Conclusion. The importance of life experience in regard to health care by senior can be seen as a resource. Qualitative studies investigating physician-patient relationships and intergenerational aspects in CAM use could be of interest for further studies. PMID:24023586

  16. Structural Studies of Bacterioferritin B from Pseudomonas aeruginosa Suggest a Gating Mechanism for Iron Uptake via the Ferroxidase Center

    SciTech Connect

    Weeratunga, Saroja K.; Lovell, Scott; Yao, Huili; Battaile, Kevin P.; Fischer, Christopher J.; Gee, Casey E.; Rivera, Mario

    2010-03-16

    The structure of recombinant Pseudomonas aeruginosa bacterioferritin B (Pa BfrB) has been determined from crystals grown from protein devoid of core mineral iron (as-isolated) and from protein mineralized with {approx}600 iron atoms (mineralized). Structures were also obtained from crystals grown from mineralized BfrB after they had been soaked in an FeSO{sub 4} solution (Fe soak) and in separate experiments after they had been soaked in an FeSO{sub 4} solution followed by a soak in a crystallization solution (double soak). Although the structures consist of a typical bacterioferritin fold comprised of a nearly spherical 24-mer assembly that binds 12 heme molecules, comparison of microenvironments observed in the distinct structures provided interesting insights. The ferroxidase center in the as-isolated, mineralized, and double-soak structures is empty. The ferroxidase ligands (except His130) are poised to bind iron with minimal conformational changes. The His130 side chain, on the other hand, must rotate toward the ferroxidase center to coordinate iron. In comparison, the structure obtained from crystals soaked in an FeSO{sub 4} solution displays a fully occupied ferroxidase center and iron bound to the internal, Fe{sub (in)}, and external, Fe{sub (out)}, surfaces of Pa BfrB. The conformation of His130 in this structure is rotated toward the ferroxidase center and coordinates an iron ion. The structures also revealed a pore on the surface of Pa BfrB that likely serves as a port of entry for Fe{sup 2+} to the ferroxidase center. On its opposite end, the pore is capped by the side chain of His130 when it adopts its 'gate-closed' conformation that enables coordination to a ferroxidase iron. A change to its 'gate-open', noncoordinative conformation creates a path for the translocation of iron from the ferroxidase center to the interior cavity. These structural observations, together with findings obtained from iron incorporation measurements in solution, suggest that

  17. A GC/MS study of the drying of ballpoint pen ink on paper.

    PubMed

    Weyermann, Céline; Kirsch, Dieter; Costa Vera, César; Spengler, Bernhard

    2007-05-24

    The determination of the age of an ink entry from a questioned document is often an essential problem and a controversial issue in forensic sciences. Therefore, it is important to understand the aging process of the different components found in ink. The aim of this work was to study the drying process of ballpoint ink, characterised by the disappearance of volatile solvents from the ink entry. Phenoxyethanol is of particularly high interest as it is found in more than 80% of the blue ballpoint pens at different concentrations. Liquid extraction followed by splitless gas chromatography/mass spectrometry in the selected ion mode was used to measure the quantitative decrease of solvents from ink entries made with a blue Parker ballpoint pen. Quantities of ethoxyethoxyethanol, dipropylene glycol, phenoxyethanol and phenoxyethoxyethanol were studied in ink entries up to 1.5 years old, thus allowing to calculate aging curves for this particular pen. The low quantities of solvents (in the microgram range for a 1 cm ballpoint entry) were found to decrease quickly after deposition of the ink on paper through the competitive processes of evaporation and diffusion. Losses of up to 75% of solvents were observed after a few seconds. The amount of ethoxyethanol stopped decreasing after about 10 days (quantities reached the nanogram range for a 1 cm ballpoint entry), while the aging curves of dipropylene glycol, phenoxyethanol and phenoxyethoxyethanol level off considerably after 2 weeks. It was observed that ethoxyethanol, dipropylene glycol and phenoxyethanol can also migrate from one sheet of paper to another if placed close enough (e.g. in a book or a stack of papers), therefore contamination from fresh ink strokes from other paper sheets has to be taken into account for those solvents. In this paper we demonstrate that differentiation between fresh ink (<2 weeks) and older inks is possible under laboratory storage conditions. For real cases samples, more parameters have to

  18. An automated data analysis pipeline for GC-TOF-MS metabonomics studies.

    PubMed

    Jiang, Wenxin; Qiu, Yunping; Ni, Yan; Su, Mingming; Jia, Wei; Du, Xiuxia

    2010-11-05

    Recent technological advances have made it possible to carry out high-throughput metabonomics studies using gas chromatography coupled with time-of-flight mass spectrometry. Large volumes of data are produced from these studies and there is a pressing need for algorithms that can efficiently process and analyze data in a high-throughput fashion as well. We present an Automated Data Analysis Pipeline (ADAP) that has been developed for this purpose. ADAP consists of peak detection, deconvolution, peak alignment, and library search. It allows data to flow seamlessly through the analysis steps without any human intervention and features two novel algorithms in the analysis. Specifically, clustering is successfully applied in deconvolution to resolve coeluting compounds that are very common in complex samples and a two-phase alignment process has been implemented to enhance alignment accuracy. ADAP is written in standard C++ and R and uses parallel computing via Message Passing Interface for fast peak detection and deconvolution. ADAP has been applied to analyze both mixed standards samples and serum samples and identified and quantified metabolites successfully. ADAP is available at http://www.du-lab.org .

  19. A Genome-Wide Association Study Suggests Novel Loci Associated with a Schizophrenia-Related Brain-Based Phenotype

    PubMed Central

    Hass, Johanna; Walton, Esther; Kirsten, Holger; Liu, Jingyu; Priebe, Lutz; Wolf, Christiane; Karbalai, Nazanin; Gollub, Randy; White, Tonya; Roessner, Veit; Müller, Kathrin U.; Paus, Tomas; Smolka, Michael N.; Schumann, Gunter; Scholz, Markus; Cichon, Sven; Calhoun, Vince; Ehrlich, Stefan

    2013-01-01

    Patients with schizophrenia and their siblings typically show subtle changes of brain structures, such as a reduction of hippocampal volume. Hippocampal volume is heritable, may explain a variety of cognitive symptoms of schizophrenia and is thus considered an intermediate phenotype for this mental illness. The aim of our analyses was to identify single-nucleotide polymorphisms (SNP) related to hippocampal volume without making prior assumptions about possible candidate genes. In this study, we combined genetics, imaging and neuropsychological data obtained from the Mind Clinical Imaging Consortium study of schizophrenia (n = 328). A total of 743,591 SNPs were tested for association with hippocampal volume in a genome-wide association study. Gene expression profiles of human hippocampal tissue were investigated for gene regions of significantly associated SNPs. None of the genetic markers reached genome-wide significance. However, six highly correlated SNPs (rs4808611, rs35686037, rs12982178, rs1042178, rs10406920, rs8170) on chromosome 19p13.11, located within or in close proximity to the genes NR2F6, USHBP1, and BABAM1, as well as four SNPs in three other genomic regions (chromosome 1, 2 and 10) had p-values between 6.75×10−6 and 8.3×10−7. Using existing data of a very recently published GWAS of hippocampal volume and additional data of a multicentre study in a large cohort of adolescents of European ancestry, we found supporting evidence for our results. Furthermore, allelic differences in rs4808611 and rs8170 were highly associated with differential mRNA expression in the cis-acting region. Associations with memory functioning indicate a possible functional importance of the identified risk variants. Our findings provide new insights into the genetic architecture of a brain structure closely linked to schizophrenia. In silico replication, mRNA expression and cognitive data provide additional support for the relevance of our findings. Identification of

  20. Lornoxicam Immediate-Release Tablets: Formulation and Bioequivalence Study in Healthy Mediterranean Volunteers Using a Validated LC-MS/MS Method.

    PubMed

    Zaid, Abdel Naser; Mousa, Ayman; Jaradat, Nidal; Bustami, Rana

    2017-02-08

    This study aimed to demonstrate interchangeability between 2 lornoxicam tablet formulations under fasting conditions among Mediterranean Arabs by using a newly validated high-pressure liquid chromatography-tandem mass spectrometry method. A single-oral solid dosage form (8 mg/tablet), randomized, open-label, 2-way crossover study was conducted on 30 healthy male volunteers. Blood samples were collected prior to dosing and over a 24-hour period, and the washout period was 9 days. Statistical comparison of the main pharmacokinetic parameters showed no significant difference between generic and branded products. The point estimates (ratios of geometric mean %) were 90.91, 96.34, and 94.86 for Cmax, AUC0-last , and AUC0-∞ , respectively. The 90% confidence intervals were within the predefined limits of 80.00%-125.00%, as specified by the international guidelines. This study showed that both formulations met the regulatory criteria for bioequivalence.

  1. Experimental and Theoretical Study of Propeller Spinner/Shank Interference. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Cornell, C. C.

    1986-01-01

    A fundamental experimental and theoretical investigation into the aerodynamic interference associated with propeller spinner and shank regions was conducted. The research program involved a theoretical assessment of solutions previously proposed, followed by a systematic experimental study to supplement the existing data base. As a result, a refined computational procedure was established for prediction of interference effects in terms of interference drag and resolved into propeller thrust and torque components. These quantities were examined with attention to engineering parameters such as two spinner finess ratios, three blade shank forms, and two/three/four/six/eight blades. Consideration of the physics of the phenomena aided in the logical deduction of two individual interference quantities (cascade effects and spinner/shank juncture interference). These interference effects were semi-empirically modeled using existing theories and placed into a compatible form with an existing propeller performance scheme which provided the basis for examples of application.

  2. LA-ICP-MS Study of Trace Elements in the Chanuskij Metal

    NASA Technical Reports Server (NTRS)

    Petaev, Michail I.

    2005-01-01

    This progress report covers work done during the second year of the 3-year proposal. During this year we resolved many issues relevant to the analytical technique developed by us for measuring trace elements in meteoritic metals. This technique was used to measure concentrations of Fe, Ni, Co, Cr, Cu, Ga, Ge, As, Mo, Ru, Rh, Pd, Sb, W, Re, Os, Ir, Pt, and Au in eight large (120 - 160 microns) metal grains from both "igneous" and "metamorphic" lithologies of the Chanuskij silicate inclusions. The first application of OUT technique to metal grains from thin sections showed some limitations. Small thickness of metal grains in the thin section limited the signal to 3-4 time-slices instead of 10- 1 1 ones in polished sections of iron meteorites studied before.

  3. Theoretical spectroscopic studies and identification of metal-citrate (Cd and Pb) complexes by ESI-MS in aqueous solution

    NASA Astrophysics Data System (ADS)

    Bertoli, Alexandre C.; Carvalho, Ruy; Freitas, Matheus P.; Ramalho, Teodorico C.; Mancini, Daiana T.; Oliveira, Maria C.; de Varennes, Amarílis; Dias, Ana

    2015-02-01

    The combined use of ESI-MS, FTIR-ATR and theoretical calculations for the determination of metal-citrate (metal = Cd and Pb) structures are reported. Mass spectrometry allowed to determine the stoichiometry 1:1 and 2:1 of the complexes, corroborating the theoretical calculations. The species found in the ratio 2:1 had their molecular structures readjusted, since the deprotonation of citric acid differed from what was simulated. The calculations of thermodynamic stability (ΔH0(aq.)) for the complexes obtained by B3LYP/LANL2DZ were more exoenergetic than those found by PM6. However, for both methods, the stability of the complexes follows a trend, that is, the lowest-energy isomers in PM6 are also the most stable in B3LYP/LANL2DZ. The infrared analysis suggested that carboxyl groups are complexation sites and hydrogen bonds can help in the stability of the complexes. The vibrational frequencies in B3LYP/LANL2DZ had a good correlation with the experimental infrared results.

  4. Towards a phylogenetic generic classification of Thelypteridaceae: Additional sampling suggests alterations of neotropical taxa and further study of paleotropical genera.

    PubMed

    Almeida, Thaís Elias; Hennequin, Sabine; Schneider, Harald; Smith, Alan R; Batista, João Aguiar Nogueira; Ramalho, Aline Joseph; Proite, Karina; Salino, Alexandre

    2016-01-01

    Thelypteridaceae is one of the largest fern families, having about 950 species and a cosmopolitan distribution but with most species occurring in tropical and subtropical regions. Its generic classification remains controversial, with different authors recognizing from one up to 32 genera. Phylogenetic relationships within the family have not been exhaustively studied, but previous studies have confirmed the monophyly of the lineage. Thus far, sampling has been inadequate for establishing a robust hypothesis of infrafamilial relationships within the family. In order to understand phylogenetic relationships within Thelypteridaceae and thus to improve generic reclassification, we expand the molecular sampling, including new samples of Old World taxa and, especially, many additional neotropical representatives. We also explore the monophyly of exclusively or mostly neotropical genera Amauropelta, Goniopteris, Meniscium, and Steiropteris. Our sampling includes 68 taxa and 134 newly generated sequences from two plastid genomic regions (rps4-trnS and trnL-trnF), plus 73 rps4 and 72 trnL-trnF sequences from GenBank. These data resulted in a concatenated matrix of 1980 molecular characters for 149 taxa. The combined data set was analyzed using maximum parsimony and bayesian inference of phylogeny. Our results are consistent with the general topological structure found in previous studies, including two main lineages within the family: phegopteroid and thelypteroid. The thelypteroid lineage comprises two clades; one of these included the segregates Metathelypteris, Coryphopteris, and Amauropelta (including part of Parathelypteris), whereas the other comprises all segregates of Cyclosorus s.l., such as Goniopteris, Meniscium, and Steiropteris (including Thelypteris polypodioides, previously incertae sedis). The three mainly neotropical segregates were found to be monophyletic but nested in a broadly defined Cyclosorus. The fourth mainly neotropical segregate, Amauropelta

  5. A validated LC-MS/MS method of total and unbound lenvatinib quantification in human serum for protein binding studies by equilibrium dialysis.

    PubMed

    Mano, Yuji; Kusano, Kazutomi

    2015-10-10

    A sensitive method for the determination of total and unbound lenvatinib (Lenvima™), a novel tyrosine kinase inhibitor, in human serum was developed for protein binding studies using an equilibrium dialysis and liquid chromatography with tandem mass spectrometry. Serum samples (0.8 mL) were dialyzed against phosphate buffered saline (PBS) in dialyzer for 18 h at 37 °C to obtain dialysate and serum for unbound and total lenvatinib, respectively. After extraction by organic solvent, separation was achieved on a Symmetry Shield RP8 column with isocratic elution of 2 mM ammonium acetate (pH 4.0)-acetonitrile (3:2, v/v) at the flow rate of 0.2 mL/min. Detection was performed using API4000 with multiple reaction monitoring mode using positive electrospray ionization. The standard curve ranged from 0.0400 to 16.0 ng/mL and 0.0800 to 400 ng/mL as lenvatinib free base in PBS and serum, respectively. Accuracy and precision in the intra- and inter-batch reproducibility study were within the acceptance criteria. Various stability assessments including bench-top, freeze/thaw, processed samples, and frozen stability confirmed that lenvatinib was stable in serum and PBS. Application to in vivo protein binding studies in clinical studies was successfully performed and results showed that lenvatinib was highly protein bound in serum.

  6. HIV-associated neurocognitive disease: case studies and suggestions for diagnosis and management in different patient subgroups.

    PubMed

    Pozniak, Anton; Rackstraw, Simon; Deayton, Jane; Barber, Tristan; Taylor, Steve; Manji, Hadi; Melvin, Diane; Croston, Michelle; Nightingale, Sam; Kulasegaram, Ranubabu; Pitkanen, Mervi; Winston, Alan

    2014-01-01

    The incidence of HIV-associated dementia has decreased significantly with the introduction of combination antiretroviral therapy; however, milder or more subtle forms of neurocognitive disorders associated with HIV appear to remain common. There is a lack of consensus on when to screen and on which methods are most appropriate for identifying patients at risk of neurocognitive impairment. Multiple factors (demographic, social, genetic, psychological and medical) can play a role in its aetiology and progression, including potential central nervous system toxicity of antiviral therapy. It is important to identify these factors in order to apply relevant management strategies. In this review, we discuss a series of case studies that address some of the challenges presented by the diagnosis and management of HIV-associated neurocognitive impairment in different patient types.

  7. Microtopography of the eye surface of the crab Carcinus maenas: an atomic force microscope study suggesting a possible antifouling potential.

    PubMed

    Greco, G; Lanero, T Svaldo; Torrassa, S; Young, R; Vassalli, M; Cavaliere, A; Rolandi, R; Pelucchi, E; Faimali, M; Davenport, J

    2013-07-06

    Marine biofouling causes problems for technologies based on the sea, including ships, power plants and marine sensors. Several antifouling techniques have been applied to marine sensors, but most of these methodologies are environmentally unfriendly or ineffective. Bioinspiration, seeking guidance from natural solutions, is a promising approach to antifouling. Here, the eye of the green crab Carcinus maenas was regarded as a marine sensor model and its surface characterized by means of atomic force microscopy. Engineered surface micro- and nanotopography is a new mechanism found to limit biofouling, promising an effective solution with much reduced environmental impact. Besides giving a new insight into the morphology of C. maenas eye and its characterization, our study indicates that the eye surface probably has antifouling/fouling-release potential. Furthermore, the topographical features of the surface may influence the wettability properties of the structure and its interaction with organic molecules. Results indicate that the eye surface micro- and nanotopography may lead to bioinspired solutions to antifouling protection.

  8. Study on the protective role of selenium against cadmium toxicity in lactic acid bacteria: an advanced application of ICP-MS.

    PubMed

    Araúz, Iris Liliana Caballero; Afton, Scott; Wrobel, Kazimierz; Caruso, Joseph A; Corona, J Felix Gutiérrez; Wrobel, Katarzyna

    2008-05-30

    In this work, Lactobacillus casei rhamnosus were obtained from the commercial product of fermented milk and possible antagonistic effect of selenium (as sodium selenite) against cadmium toxicity was studied. The bacteria capability to incorporate Se was demonstrated: after 1 week exposure to Se(IV), its total concentration in the freeze-dried biomass was 405+/-28 microg/g (7.4+/-0.8 microg/g in control). In the presence of Se(IV) and Cd(II), the bacterial growth and cell viability were improved and lipid peroxidation less marked with respect to bacteria exposed to Cd(II) alone. The distribution of Se and Cd in molecular mass fractions of bacteria extracts was investigated by size exclusion chromatography with diode array and ICP-MS detection. The results obtained suggest that the antagonistic effect of Se is due to lower incorporation of cadmium at a high molecular mass (MM<600 kDa). Slightly different distribution of elements in the fractions of MM<40 kDa suggests the formation of new chemical species involving Cd and Se in bacteria exposed to Cd(II)+Se(IV) as compared to those exposed to Cd(II) alone. The study illustrates the high utility of atomic spectrometry to critically inform molecular questions that could be important in the industrial processes based on bacterial activity.

  9. A study of the polarization of light scattered by vegetation. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Woessner, P. N.

    1985-01-01

    This study was undertaken in order to better understand the factors that govern the polarization of light scattered from vegetation and soils. The intensity and polarization of light scattered by clover and grass in vivo and soil were measured at a number of different angles of incidence and reflectance. Both individual leaves and natural patches of leaves were measured. The light transmitted through the leaves was found to be negatively polarized. The light scattered from the upper leaf surface was found to be positively polarized in a manner which could be accounted for qualitatively but not quantitatively by the Fresnel reflection coefficients modified by a shadowing function of the form cos sup2 (g/2), where g is the phase angle. Findings indicate that the polarization of light scattered by vegetation is a more complex process than previously thought, and that besides the surface-scattered component of light, the volume-scattered and multiply-scattered components also contribute significantly to the polarization.

  10. Microtopography of the eye surface of the crab Carcinus maenas: an atomic force microscope study suggesting a possible antifouling potential

    PubMed Central

    Greco, G.; Lanero, T. Svaldo; Torrassa, S.; Young, R.; Vassalli, M.; Cavaliere, A.; Rolandi, R.; Pelucchi, E.; Faimali, M.; Davenport, J.

    2013-01-01

    Marine biofouling causes problems for technologies based on the sea, including ships, power plants and marine sensors. Several antifouling techniques have been applied to marine sensors, but most of these methodologies are environmentally unfriendly or ineffective. Bioinspiration, seeking guidance from natural solutions, is a promising approach to antifouling. Here, the eye of the green crab Carcinus maenas was regarded as a marine sensor model and its surface characterized by means of atomic force microscopy. Engineered surface micro- and nanotopography is a new mechanism found to limit biofouling, promising an effective solution with much reduced environmental impact. Besides giving a new insight into the morphology of C. maenas eye and its characterization, our study indicates that the eye surface probably has antifouling/fouling-release potential. Furthermore, the topographical features of the surface may influence the wettability properties of the structure and its interaction with organic molecules. Results indicate that the eye surface micro- and nanotopography may lead to bioinspired solutions to antifouling protection. PMID:23635491

  11. Study on the pharmacokinetics profiles of polyphyllin I and its bioavailability enhancement through co-administration with P-glycoprotein inhibitors by LC-MS/MS method.

    PubMed

    Zhu, He; Zhu, Si-Can; Shakya, Shailendra; Mao, Qian; Ding, Chuan-Hua; Long, Min-Hui; Li, Song-Lin

    2015-03-25

    Polyphyllin I (PPI), one of the steroidal saponins in Paris polyphylla, is a promising natural anticancer candidate. Although the anticancer activity of PPI has been well demonstrated, information regarding the pharmacokinetics and bioavailability is limited. In this study, a series of reliable and rapid liquid chromatography-tandem mass spectrometry methods were developed and successfully applied to determinate PPI in rat plasma, cell incubation media and cell homogenate. Then the pharmacokinetics of PPI in rats was studied and the result revealed that PPI was slowly eliminated with low oral bioavailability (about 0.62%) at a dose of 50 mg/kg, and when co-administrated with verapamil (VPL) and cyclosporine A (CYA), the oral bioavailability of PPI could increase from 0.62% to 3.52% and 3.79% respectively. In addition, in vitro studies showed that with the presence of VPL and CYA in Caco-2 cells, the efflux ratio of PPI decreased from 12.5 to 2.96 and 2.22, and the intracellular concentrations increased 5.8- and 5.0-fold respectively. These results demonstrated that PPI, with poor oral bioavailability, is greatly impeded by P-gp efflux, and inhibition of P-gp can enhance its bioavailability.

  12. Analysis of educational research at a medical faculty in Germany and suggestions for strategic development - a case study.

    PubMed

    Prediger, Sarah; Harendza, Sigrid

    2016-01-01

    Background: Evidence-based medical education is playing an increasingly important role in the choice of didactic methods and the development of medical curricula and assessments. In Germany, a growing number of educational research projects has accompanied an ongoing change in the medical education process. The aim of this project was to assess medical education research activities at one medical faculty to develop procedural recommendations for the support and development of best evidence medical education. Methods: Using a newly developed online questionnaire, the 65 institutes and departments of the medical faculty of Hamburg University at Hamburg University Medical-Center (UKE) were asked to report their medical education research and service projects, medical education publications, medical education theses, financial support for educational projects, and supportive structures that they would consider helpful in the future. The data were grouped, and a SWOT analysis was performed. Results: In total, 60 scientists who were involved in 112 medical education research publications between 1998 and 2014 were identified at the UKE. Twenty-five of them had published at least one manuscript as first or last author. Thirty-three UKE institutions were involved in educational service or research projects at the time of the study, and 75.8% of them received internal or external funding. Regular educational research meetings and the acquisition of co-operation partners were mentioned most frequently as beneficial supportive structures for the future. Conclusion: An analysis to define the status quo of medical education research at a medical faculty seems to be a helpful first step for the development of a strategy and structure to further support researchers in medical education.

  13. Analysis of educational research at a medical faculty in Germany and suggestions for strategic development – a case study

    PubMed Central

    Prediger, Sarah; Harendza, Sigrid

    2016-01-01

    Background: Evidence-based medical education is playing an increasingly important role in the choice of didactic methods and the development of medical curricula and assessments. In Germany, a growing number of educational research projects has accompanied an ongoing change in the medical education process. The aim of this project was to assess medical education research activities at one medical faculty to develop procedural recommendations for the support and development of best evidence medical education. Methods: Using a newly developed online questionnaire, the 65 institutes and departments of the medical faculty of Hamburg University at Hamburg University Medical-Center (UKE) were asked to report their medical education research and service projects, medical education publications, medical education theses, financial support for educational projects, and supportive structures that they would consider helpful in the future. The data were grouped, and a SWOT analysis was performed. Results: In total, 60 scientists who were involved in 112 medical education research publications between 1998 and 2014 were identified at the UKE. Twenty-five of them had published at least one manuscript as first or last author. Thirty-three UKE institutions were involved in educational service or research projects at the time of the study, and 75.8% of them received internal or external funding. Regular educational research meetings and the acquisition of co-operation partners were mentioned most frequently as beneficial supportive structures for the future. Conclusion: An analysis to define the status quo of medical education research at a medical faculty seems to be a helpful first step for the development of a strategy and structure to further support researchers in medical education. PMID:27990467

  14. Time Dependency of Chemodiversity and Biosynthetic Pathways: An LC-MS Metabolomic Study of Marine-Sourced Penicillium

    PubMed Central

    Roullier, Catherine; Bertrand, Samuel; Blanchet, Elodie; Peigné, Mathilde; Robiou du Pont, Thibaut; Guitton, Yann; Pouchus, Yves François; Grovel, Olivier

    2016-01-01

    This work aimed at studying metabolome variations of marine fungal strains along their growth to highlight the importance of the parameter “time” for new natural products discovery. An untargeted time-scale metabolomic study has been performed on two different marine-derived Penicillium strains. They were cultivated for 18 days and their crude extracts were analyzed by HPLC-DAD-HRMS (High Performance Liquid Chromatography-Diode Array Detector-High Resolution Mass Spectrometry) each day. With the example of griseofulvin biosynthesis, a pathway shared by both strains, this work provides a new approach to study biosynthetic pathway regulations, which could be applied to other metabolites and more particularly new ones. Moreover, the results of this study emphasize the interest of such an approach for the discovery of new chemical entities. In particular, at every harvesting time, previously undetected features were observed in the LC-MS (Liquid Chromatography-Mass Spectrometry) data. Therefore, harvesting times for metabolite extraction should be performed at different time points to access the hidden metabolome. PMID:27213411

  15. Metabolomic and elemental analysis of camel and bovine urine by GC-MS and ICP-MS.

    PubMed

    Ahamad, Syed Rizwan; Alhaider, Abdul Qader; Raish, Mohammad; Shakeel, Faiyaz

    2017-01-01

    Recent studies from the author's laboratory indicated that camel urine possesses antiplatelet activity and anti-cancer activity which is not present in bovine urine. The objective of this study is to compare the volatile and elemental components of bovine and camel urine using GC-MS and ICP-MS analysis. We are interested to know the component that performs these biological activities. The freeze dried urine was dissolved in dichloromethane and then derivatization process followed by using BSTFA for GC-MS analysis. Thirty different compounds were analyzed by the derivatization process in full scan mode. For ICP-MS analysis twenty eight important elements were analyzed in both bovine and camel urine. The results of GC-MS and ICP-MS analysis showed marked difference in the urinary metabolites. GC-MS evaluation of camel urine finds a lot of products of metabolism like benzene propanoic acid derivatives, fatty acid derivatives, amino acid derivatives, sugars, prostaglandins and canavanine. Several research reports reveal the metabolomics studies on camel urine but none of them completely reported the pharmacology related metabolomics. The present data of GC-MS suggest and support the previous studies and activities related to camel urine.

  16. A highly sensitive LC-MS/MS method capable of simultaneously quantitating celiprolol and atenolol in human plasma for a cassette cold-microdosing study.

    PubMed

    Minamide, Yoshiyuki; Osawa, Yukio; Nishida, Hiroshi; Igarashi, Harue; Kudoh, Shinobu

    2011-07-01

    A highly sensitive simultaneous quantitative method for a cassette cold-microdosing study on celiprolol and atenolol was developed with liquid chromatography-tandem mass spectrometry. The method utilizes a combination of solid-phase extraction (SPE) with strong cation exchange (SCX) cartridge columns and reversed-phase chromatography with an ODS analytical column. SCX-SPE cartridge columns (100 mg sorbent) were used for a selective extraction of celiprolol, atenolol and metoprolol (internal standard) from 500 μL of human plasma samples. Turbo-ion spray at positive mode was employed for the ionization of the drug compounds. Quantitation was performed on a triple quadrupole mass spectrometer by selected reaction monitoring with the transitions of m/z 380 to m/z 251 for celiprolol and m/z 267 to m/z 145 for atenolol. Separation of analytes was achieved on an ODS column (100 mm length × 2.1 mm id, 3 μm) by a gradient elution with 10 mM formic acid and methanol by varying their proportion at a flow rate of 0.2 mL/min. The method was validated in the range of 1-250 pg/mL for celiprolol and 2.5-250 pg/mL for atenolol and was successfully applied to the elucidation of pharmacokinetic profiling in a cold cassette microdosing study of the β-blockers.

  17. LC-MS/MS method development for quantification of doxorubicin and its metabolite 13-hydroxy doxorubicin in mice biological matrices: Application to a pharmaco-delivery study.

    PubMed

    Mazzucchelli, Serena; Ravelli, Alessandro; Gigli, Fausto; Minoli, Mauro; Corsi, Fabio; Ciuffreda, Pierangela; Ottria, Roberta

    2017-04-01

    This study describes the development of simple, rapid and sensitive liquid chromatography tandem mass spectrometry method for the simultaneous analysis of doxorubicin and its major metabolite, doxorubicinol, in mouse plasma, urine and tissues. The calibration curves were linear over the range 5-250 ng/mL for doxorubicin and 1.25-25 ng/mL for doxorubicinol in plasma and tumor, over the range 25-500 ng/mL for doxorubicin and 1.25-25 ng/mL for doxorubicinol in liver and kidney, and over the range 25-1000 ng/mL for doxorubicin and doxorubicinol in urine. The study was validated, using quality control samples prepared in all different matrices, for accuracy, precision, linearity, selectivity, lower limit of quantification and recovery in accordance with the US Food & Drug Administration guidelines. The method was successfully applied in determining the pharmaco-distribution of doxorubicin and doxorubicinol after intravenously administration in tumor-bearing mice of drug, free or nano-formulated in ferritin nanoparticles or in liposomes. Obtained results demonstrate an effective different distribution and doxorubicin protection against metabolism linked to nano-formulation. This method, thanks to its validation in plasma and urine, could be a powerful tool for pharmaceutical research and therapeutic drug monitoring, which is a clinical approach currently used in the optimization of oncologic treatments.

  18. A rapid and simple UPLC-MS-MS method for determination of glipizide in human plasma and its application to bioequivalence study.

    PubMed

    Qiu, Xiangjun; Zheng, Shuang-li; Wang, Yingfei; Wang, Rong; Ye, Lei

    2015-01-01

    In this study, a simple, rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry method is described for the determination of glipizide in human plasma samples using carbamazepine as the internal standard (IS) from bioequivalence assays. Sample preparation was accomplished through protein precipitation with methanol, and chromatographic separation was performed on an Acquity BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with gradient profile at a flow rate of 0.4 mL/min. Mass spectrometric analysis was performed using an QTrap5500 mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The multiple reaction monitoring transitions of m/z 446.1 → 321.0 and m/z 237.1 → 194.2 were used to quantify for glipizide and IS. The linearity of this method was found to be within the concentration range of 10-1,500 ng/mL for glipizide in human plasma. Only 1.0 min was needed for an analytical run. The method was applied to a bioequivalence study of two drug products containing glipizide in human plasma samples.

  19. Disposable chromatography for a high-throughput nano-ESI/MS and nano-ESI/MS-MS platform.

    PubMed

    Williams, Jason G; Tomer, Kenneth B

    2004-09-01

    High-throughput proteomics has typically relied on protein identification based on MALDI-MS peptide maps of proteolytic digests of 2D-gel-separated proteins. This technique, however, requires significant sequence coverage in order to achieve a high level of confidence in the identification. Tandem MS data have the advantage of requiring fewer peptides (2) for high confidence identification, assuming adequate MS/MS sequence coverage. MALDI-MS/MS techniques are becoming available, but can still be problematic because of the difficulty of inducing fragment ions of a singly charged parent ion. Electrospray ionization, however, has the advantage of generating multiply charged species that are more readily fragmented during MS/MS analysis. Two electrospray/tandem mass spectrometry-based approaches, nanovial-ESI-MS/MS and LC-MS/MS, are used for high throughput proteomics, but much less often than MALDI-MS and peptide mass fingerprinting. Nanovial introduction entails extensive manual manipulation and often shows significant chemical background from the in-gel digest. LC-MS has the advantages that the chemical background can be removed prior to analysis and the analytes are concentrated during the separation, resulting in more abundant analyte signals. On the other hand, LC-MS can often be time intensive. Here, we report the incorporation of on-line sample clean-up and analyte concentration with a high-throughput, chip-based, robotic nano-ESI-MS platform for proteomics studies.

  20. LC-MS/MS determination of cinacalcet enantiomers in rat plasma on Chirobiotic V column in polar ionic mode: application to a pharmacokinetic study.

    PubMed

    Ramisetti, Nageswara Rao; Bompelli, Sravan

    2014-12-01

    A simple and selective polar ionic liquid chromatography-tandem mass spectrometric method for separation and determination of cinacalcet enantiomers in rat plasma was developed and validated. The chromatographic separation was accomplished on a Chirobiotic V column packed with vancomycin as a chiral stationary phase using 2.5 mm ammonium formate in 100% methanol as a mobile phase in an isocratic mode of elution at a flow rate of 1.0 mL/min. The analytes were extracted from rat plasma by precipitating the proteins with acetonitrile. The developed method exhibited a linear dynamic range over 0.5-500 ng/mL in rat plasma for both enantiomers. The method was successfully applied to study the pharmacokinetics after a single dose by oral administration of 10 mg/kg of cinacalcet enantiomers to healthy male Wistar rats.

  1. Study on the simultaneous determination of seven benzoylurea pesticides in Oolong tea and their leaching characteristics during infusing process by HPLC-MS/MS.

    PubMed

    Chen, Lei; Chen, JinFa; Guo, Ying; Li, JianRong; Yang, YiQiang; Xu, LiangJun; Fu, FengFu

    2014-01-15

    A method for the simultaneous determination of 7 benzoylurea pesticides (chlorfluazuron, diflubenzuron, fluazuron, flufenoxuron, hexaflumuron, teflubenzuron and triflumuron) in the manufactured Oolong tea leaves and its infusion was described. The method has a LOD of 0.03-1.00ng/mL, a recovery of 90.4-103% for made tea and 90.3-102% for tea-infused liquid, respectively. By using the proposed method, the leaching characteristics of above 7 pesticides during infusing process were investigated. The experimental results revealed that: (1) diflubenzuron can be most easily extracted out during infusing process, followed by triflumuron, teflubenzuron, hexaflumuron, chlorfluazuron, flufenoxuron and fluazuron. (2) The leaching of flufenoxuron and chlorfluazuron during infusing process seems to be controlled by only their solubility, whereas, the leaching of other 5 benzoylurea insecticides was primarily controlled by their partitioning coefficient between made tea and hot water. The results of this study are helpful for the accurate evaluation of the safety of Oolong tea.

  2. Reliable LC-MS/MS assay for the estimation of rilpivirine in human plasma: application to a bioequivalence study and incurred sample reanalysis.

    PubMed

    Gupta, Ajay; Guttikar, Swati; Patel, Yogesh; Shrivastav, Pranav S; Sanyal, Mallika

    2015-04-01

    A simple, precise, and rapid stable isotope dilution liquid chromatography-tandem mass spectrometry method has been developed and validated for the quantification of rilpivirine, a non-nucleoside reverse transcriptase inhibitor in human plasma. Rilpivirine and its deuterated analogue, rilpivirine-d6, used as an internal standard (IS) were quantitatively extracted by liquid-liquid extraction with methyl-tert-butyl ether and diethyl ether solvent mixture from 50 μL plasma. The chromatography was achieved on Gemini C18 (150 × 4.6 mm, 5 µm) analytical column in a run time of 2.2 min. The precursor → product ion transitions for rilpivirine (m/z 367.1 → 128.0) and IS (m/z 373.2 → 134.2) were monitored on a triple quadrupole mass spectrometer in the positive ionization mode. The linearity of the method was established in the concentration range of 0.5-200 ng/mL. The mean extraction recovery for rilpivirine (94.9%) and IS (99.9%) from spiked plasma samples was consistent and reproducible. The IS-normalized matrix factors for rilpivirine ranged from 0.98 to 1.02 across three quality controls. Bench top, freeze-thaw, wet extract, and long-term stability of rilpivirine was examined in spiked plasma samples. The application of the method was demonstrated by a bioequivalence study with 25 mg rilpivirine tablet formulation in 40 healthy subjects. The assay reproducibility was shown by reanalysis of 200 study samples and the % change in the concentration of repeat values from the original values was within ±15%.

  3. Simultaneous determination of multiple bioactive components of Bu-zhong-yi-qi-tang in rat tissues by LC-MS/MS: Application to a tissue distribution study.

    PubMed

    He, Min; Chen, Wenwen; Wang, Mengmeng; Wu, Yu; Zeng, Jin; Zhang, Zhirong; Shen, Shujiao; Jiang, Jian

    2017-02-15

    A liquid chromatography coupled with electrospray ionization mass spectrometry method was developed and validated for simultaneous determination of seven bioactive constituents including astragaloside IV, calycosin, glycyrrhizic acid, enoxolone, saikosaponin D, ferulic acid and hesperiden in rats' various tissues using diclofenac as the internal standard (IS). Biological samples were pretreated by protein precipitation with acetonitrile. The chromatographic separation was carried out on a C18 column with a gradient mobile phase consisting of acetonitrile and water (containing 0.1% formic acid and 4mM ammonium acetate). All analytes and IS were quantitated through electrospray ionization in negative ion multiple reaction monitoring mode. The mass transitions were as follows: m/z 829.7→783.3 for astragaloside IV, m/z 283.3→267.7 for calycosin, m/z 821.6→350.0 for glycyrrhizic acid, m/z 469.9→425.2 for enoxolone, m/z 825.7→779.6 for saikosaponin D, m/z 192.5→133.9 for ferulic acid, m/z 609.1→301.0 for hesperiden and m/z 293.6→249.9 for the IS, respectively. The lower limits of quantification for the seven analytes in different rat tissues were 0.2-20ng/mL. Bu-zhong-yi-qi-tang (Hochuekkito in Japan, Bojungikki-tang in Korea) is one of the most frequently prescribed traditional herbal formulas used in Korea, Japan, and China to treat gastrointestinal diseases, cancer and chronic fatigue syndrome. The validated method was successfully applied to a tissue distribution study of the seven components in rat tissue after oral administration of Bu-zhong-yi-qi-tang concentrated granule. The results of the tissue distribution study showed that the high concentration of seven components were mainly in the gastrointestinal tract.

  4. Simultaneous quantification of sildenafil and N-desmethyl sildenafil in human plasma by UFLC coupled with ESI-MS/MS and pharmacokinetic and bioequivalence studies in Malay population.

    PubMed

    Liew, Kai Bin; Loh, Gabriel Onn Kit; Tan, Yvonne Tze Fung; Peh, Kok Khiang

    2015-06-01

    A simple, rapid, specific and reliable UFLC coupled with ESI-MSMS assay method to simultaneously quantify sildenafil and N-desmethyl sildenafil, with loperamide as internal standard, was developed. Chromatographic separation was performed on a Thermo Scientific Accucore C18 column with an isocratic mobile phase composed of 0.1% v/v formic acid in purified water-methanol (20:80, v/v), at a flow rate of 0.3 mL/min. Sildenafil, N-desmethyl sildenafil and loperamide were detected with proton adducts at m/z 475.4 > 58.2, 461.3 > 85.2 and 477.0 > 266.1 in multiple reaction monitoring positive mode, respectively. Both analytes and internal standard were extracted by diethyl ether. The method was validated over a linear concentration range of 10-800 ng/mL for sildenafil and 10-600 ng/mL for N-desmethyl sildenafil with correlation coefficient (r(2) ) ≥0.9976 for sildenafil and (r(2) ) ≥0.9992 for N-desmethyl sildenafil. The method was precise, accurate and stable. The proposed method was applied to study the bioequivalence between a 100 mg dose of two pharmaceutical products: Viagra (original) and Edyfil (generic) products. AUC0-t , Cmax and Tmax were 2285.79 ng h/mL, 726.10 ng/mL and 0.94 h for Viagra and 2363.25 ng h/mL, 713.91 ng/mL and 0.83 hour for Edyfil. The 90% confidence interval of these parameters of this study fall within the regulatory range of 80-125%, hence they are considered as bioequivalent.

  5. Simultaneous determination of two epimeric furofuran lignans (sesamin and asarinin) of Asarum heterotropoides extract in rat plasma by LC/MS/MS: application to pharmacokinetic study.

    PubMed

    Ma, Yingyan; Xu, Kai; Wang, Shumin; Han, Yaling

    2014-09-01

    A rapid, sensitive and selective liquid chromatography-tandem mass spectrometry was developed to determine two epimeric furofuran lignans (sesamin and asarinin) simultaneously from Asarum heterotropoides extract in rat plasma. Simple protein precipitation with acetonitrile was performed to extract analytes by using alantolactone as an internal standard. Chromatographic separation was achieved using a DIKMA Diamonsil C18 analytical column (4.6 mm × 150 mm, i.d., 5 µm) by isocratically eluting with a mobile phase consisting of methanol/5 mM ammonium acetate/formic acid (75:25:0.1, v/v/v) at a flow rate of 0.8 mL/min. Tandem mass spectrometric detection with an electrospray ionization interface was performed by multiple reaction monitoring in positive ionization mode. This method was validated according to specificity, sensitivity, linearity, intra- and inter-day precision (<10.7%) and accuracy (<2.3%) and recovery and stability in a concentration range of 25.0-15 000 ng/mL for sesamin and 5.00-3 000 ng/mL for asarinin. This method has been successfully applied in a pharmacokinetic study of A. heterotropoides extract containing sesamin and asarinin after this extract was orally administrated in rats.

  6. A sensitive and selective UPLC-MS/MS method for simultaneous determination of 10 alkaloids from Rhizoma Menispermi in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Wei, Jinxia; Fang, Linlin; Liang, Xinlei; Su, Dan; Guo, Xingjie

    2015-11-01

    A sensitive and selective liquid chromatography-tandem mass spectrometry method has been developed and validated for simultaneous quantitation of 10 alkaloids (dauricine, daurisoline, N-desmethyldauricine, dauricicoline, dauriporphinoline, bianfugecine, dauricoside, stepholidine, acutumine and acutumidine) from Rhizoma Menispermi in rat plasma. After addition of internal standard (verapamil), plasma samples were pretreated by a single-step protein precipitation with acetonitrile. Chromatographic separation was performed on a Waters BEH C18 column with gradient elution using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.3 mL/min. The analytes were detected without interference in the multiple reaction monitoring (MRM) mode with positive electrospray ionization. The validated method exhibited good linearity over a wide concentration range (r≥0.9914), and the lower limits of quantification were 0.01-5.0 ng/mL for all the analytes. The intra-day and inter-day precisions (RSD) at three different levels were both less than 13.4% and the accuracies (RE) ranged from -12.8% to 13.5%. The mean extraction recoveries of analytes and IS from rat plasma were all more than 77%. The validated method was successfully applied to a comparative pharmacokinetic study of 10 alkaloids in rat plasma after oral administration of Rhizoma Menispermi extract.

  7. Exploration of polar lipid accumulation profiles in Euglena gracilis using LipidBlast, an MS/MS spectral library constructed in silico.

    PubMed

    Ogawa, Takumi; Furuhashi, Takeshi; Okazawa, Atsushi; Nakai, Rai; Nakazawa, Masami; Kind, Tobias; Fiehn, Oliver; Kanaya, Shigehiko; Arita, Masanori; Ohta, Daisaku

    2014-01-01

    A rapid protocol for polar lipid profiling was applied to Euglena gracilis lipid metabolism by LipidBlast, an MS/MS spectral similarity search tool. The similarity search results suggested anoxia-induced polar lipid metabolism in Euglena characterized by the accumulation of differential lipid classes, carbon chain lengths, and unsaturated bond numbers. The informatics-supported MS spectral search provides an alternative option for global lipid profiling studies.

  8. Simultaneous determination and pharmacokinetic study of gambogic acid and gambogenic acid in rat plasma after oral administration of Garcinia hanburyi extracts by LC-MS/MS.

    PubMed

    Hua, Xiangdong; Liang, Chuang; Dong, Lei; Qu, Xiaotong; Zhao, Tong

    2015-04-01

    Gambogic acid and gambogenic acid are two major bioactive components of Garcinia hanburyi, and play a pivotal role in biologic activity. In this study, a specific and sensitive liquid chromatography-tandem mass spectrometry was developed and validated for simultaneous determination of gambogic acid and gambogenic acid in rat plasma. Chromatographic separation was achieved on a C18 column using an isocratic elution with methanol-10 m m ammonium acetate buffer-acetic acid (90:10:0.1, v/v/v) as the mobile phase. The detection was performed on a triple-quadrupole tandem mass spectrometer equipped with electrospray positive ionization using multiple reaction monitoring modes. The transitions monitored were m/z 629.3 [M + H](+) → 573.2 for gambogic acid, m/z 631.2 [M + H](+) → 507.2 for gambogenic acid and m/z 444.2 [M + NH4 ](+) → 83.1 for IS. Linear calibration curves were obtained in the concentration range of 2.00-1000 ng/mL for gambogic acid and 0.500-250 ng/mL for gambogenic acid. The lower limits of quantification of gambogic acid and gambogenic acid in rat plasma were 2.00 and 0.500 ng/mL, respectively. The intra- and inter-day precision (RSD) values were <11.7% and accuracy (RE) was -10.6-12.4% at three QC levels for both analytes. The assay was successfully applied to evaluate pharmacokinetics behavior in rats after oral administration of Garcinia hanburyi extracts.

  9. UPLC-MS-MS method for simultaneous determination of caffeine, tolbutamide, metoprolol, and dapsone in rat plasma and its application to cytochrome P450 activity study in rats.

    PubMed

    Liu, Yan; Li, Xiang; Yang, Chunjuan; Tai, Sheng; Zhang, Xiangning; Liu, Gaofeng

    2013-01-01

    A specific ultra-performance liquid chromatography tandem mass spectrometry method has been described for the simultaneous determination of caffeine, tolbutamide, metoprolol and dapsone in rat plasma, which are the four probe drugs of the four cytochrome P450 (CYP450) isoforms CYP1A2, CYP2C9, CYP2D6 and CYP3A4. The chromatographic separation was achieved using a Waters Acquity UPLC BEH HILIC C(18) column (2.1 × 50 mm, 1.7 µm). The mobile phase consisted of acetonitrile and water (containing 0.1% formic acid) (15:85, v/v). The triple quadrupole mass spectrometric detection was operated by positive electrospray ionization. Phenacetin was chosen as internal standard. Plasma samples were extracted with dichloromethane-butanol (10:1, v/v). The recoveries ranged from 67.5% to 98.5%. The calibration curves in plasma were linear in the range of 2.5-1,000 ng/mL for caffeine and dapsone, 5-5,000 ng/mL for tolbutamide and 2.5-250 ng/mLfor metoprolol, with correlation coefficient (r(2)) of 0.9936, 0.9966, 0.9990 and 0.9998, respectively. The method was successfully applied to pharmacokinetic studies of the four probe drugs of the four CYP450 isoforms and used to evaluate the effects of breviscapine on the activities of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 in rats.

  10. A fast and sensitive UHPLC-MS/MS method for the determination of N-butylscopolamine in human plasma: application in a bioequivalence study.

    PubMed

    Suenaga, Eunice Mayumi; Val, Ligia de Cássia; Tominaga, Mineko; Souza Filho, José Homero; Soares, Gidel; Vioto, Monalisa; Nakaie, Clovis Ryuichi

    2017-03-01

    We have developed and validated a fast and sensitive ultra high-performance liquid chromatography with positive ion electrospray ionization tandem mass spectrometry method for determining N-butylscopolamine levels in human plasma using propranolol as an internal standard. The acquisition was set up in the multiple reaction monitoring mode with the transitions m/z 360.3 → 138.0 for N-butylscopolamine and m/z 260.2 → 116.1 for IS. This method uses a liquid-liquid extraction process with dichloromethane. The analyte and IS were chromatographed on a C18 , 50 × 2.1 mm, 1.7 μm column through isocratic elution with acetonitrile-5 mm ammonium acetate (adjusted to pH 3.0 with formic acid). The method was linear in the 1-1000 pg/mL range for N-butylscopolamine and was selective, precise, accurate and robust. The validated method was successfully applied to perform a bioequivalence study of the reference (Buscopan(®) , from Boehringer Ingelheim) and the test sample coated-tablet formulations (from Foundation for Popular Remedy), both containing 10 mg of N-butylscopolamine bromide administered as a single dose. Using 58 healthy volunteers and accounting for the high intra-individual variability confirmed by statistical calculations (38%), the two formulations were considered bioequivalent because the rate and extent of absorption (within 80-125% interval), satisfying international requirements.

  11. High-Throughput Chiral LC-MS/MS Method Using Overlapping Injection Mode for the Determination of Pantoprazole Enantiomers in Human Plasma with Application to Pharmacokinetic Study.

    PubMed

    Li, Shengni; Jiang, Huafang; Wang, Yiya; Liu, Yinli; Shen, Xiaohang; Liang, Wenzhong; Hong, Zhanying

    2016-07-01

    A sensitive and high-throughput chiral liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of R-pantoprazole and S-pantoprazole in human plasma. Sample extraction was carried out by using ethyl acetate liquid-liquid extraction in 96-well plate format. The separation of pantoprazole enantiomers was performed on a CHIRALCEL OJ-RH column and an overlapping injection mode was used to achieve a run time of 5.0 min/sample. The mobile phase consisted of 1) 10 mM ammonium acetate in methanol: acetonitrile (1:1, v/v) and 2) 20 mM ammonium acetate in water. Isocratic elution was used with flow rate at 500 μL/min. The enantiomers were quantified on a triple-quadrupole mass spectrometer under multiple reaction monitoring (MRM) mode with m/z 382.1/230.0 for pantoprazole and m/z 388.4/230.1 for pantoprazole-d7. Linearity from 20.0 to 5000 ng/mL was established for each enantiomer (r(2)  > 0.99). Extraction recovery ranged from 91.7% to 96.4% for R-pantoprazole and from 92.5% to 96.5% for S-pantoprazole and the IS-normalized matrix factor was 0.98 to 1.07 for R-pantoprazole and S-pantoprazole, respectively. The method was demonstrated with acceptable accuracy, precision, selectivity, and stability and the method was applied to support a pharmacokinetic study of a phase I clinical trial of racemic pantoprazole in healthy Chinese subjects. Chirality 28:569-575, 2016. © 2016 Wiley Periodicals, Inc.

  12. Determination of Cefixime by a Validated Stability-Indicating HPLC Method and Identification of its Related Substances by LC-MS/MS Studies.

    PubMed

    Talebpour, Zahra; Pourabdollahi, Hakimeh; Rafati, Hasan; Abdollahpour, Asem; Bashour, Yusef; Aboul-Enein, Hassan Y

    2013-01-01

    Cefixime is an important cephalosporin antibiotic that easily decomposes and releases different related substances in preparation and storage steps. The objective of the current study was to develop a simple, precise, and accurate isocratic liquid chromatography (LC) method for the determination of cefixime in the presence of its related substances generated from thermal stress in the bulk drug. The chromatographic conditions were comprised of a reversed-phase C18 column (4.6 × 250 mm, 5 μm) with a mobile phase composed of water: acetonitrile (85:15 v/v, with 0.5% formic acid) and ultraviolet detection (UV). Some thermal degradation products were identified using a proposed liquid chromatography-mass spectrometry method. Five peaks (A, B, C, D, and E impurities based on British Pharmacopoeia) were known and a few unknown peaks appeared in the thermal stress solution of cefixime. The linear regression analysis data for the calibration plot of the LC-UV method showed a good linear relationship in the concentration range 0.9-1000.0 μg mL(-1). The recovery of the optimized method was between 94.6 and 98.4% and the inter- and intra-day relative standard deviations were less than 3.3%. The obtained results shown in the LC-UV proposed method can be conveniently used in a quality control laboratory for routine analysis of cefixime for the assay and related substances, as well as for the evaluation of stability samples of bulk drugs.

  13. Studies on the metabolism of the α-pyrrolidinophenone designer drug methylenedioxy-pyrovalerone (MDPV) in rat and human urine and human liver microsomes using GC-MS and LC-high-resolution MS and its detectability in urine by GC-MS.

    PubMed

    Meyer, Markus R; Du, Peng; Schuster, Frank; Maurer, Hans H

    2010-12-01

    Since the late 1990s, many derivatives of the α-pyrrolidinophenone (PPP) drug class appeared on the drugs of abuse market. The latest compound was described in 2009 to be a classic PPP carrying a methylenedioxy moiety remembering the classic entactogens (ecstasy). Besides Germany, 3,4-methylene-dioxypyrovalerone (MDPV) has appeared in many countries in Europe and Asia, indicating its worldwide importance for forensic and clinical toxicology. The aim of the presented work was to identify the phase I and II metabolites of MDPV and the human cytochrome-P450 (CYP) isoenzymes responsible for its main metabolic step(s). Finally, the detectability of MDPV in urine by the authors' systematic toxicological analysis (STA) should be studied. The urine samples were extracted after and without enzymatic cleavage of conjugates. The metabolites were separated and identified after work-up by GC-MS and liquid chromatography (LC)-high-resolution MS (LC-HR-MS). The studies revealed the following phase I main metabolic steps in rat and human: demethylenation followed by methylation, aromatic and side chain hydroxylation and oxidation of the pyrrolidine ring to the corresponding lactam as well as ring opening to the corresponding carboxylic acid. Using LC-HR-MS, most metabolite structures postulated according to GC-MS fragmentation could be confirmed and the phase II metabolites were identified. Finally, the formation of the initial metabolite demethylenyl-MDPV could be confirmed using incubation of human liver microsomes. Using recombinant human CYPs, CYP 2C19, CYP 2D6 and CYP 1A2 were found to catalyze this initial step. Finally, the STA allowed the detection of MDPV metabolites in the human urine samples.

  14. Simultaneous determination of three sesquiterpene lactones from Herba Inula extract in rat plasma by LC/MS/MS and its application to pharmacokinetic study.

    PubMed

    Yang, Xi; Su, Juan; He, Yajun; Liu, Hui; Li, Haiyun; Zhang, Weidong

    2012-08-15

    A rapid and sensitive liquid chromatography-tandem mass spectrometry method has been developed and validated for the determination of 1-acetoxy-6α-hydroxyeriolanolide, 1β-hydroxyalantolactone and ivangustin from Herba Inula extract in rat plasma. Plasma samples were pretreated by protein precipitation with methanol. Chromatographic separation was accomplished on a TOSOH TSKgel ODS column with mobile phase consisting of methanol and 0.3% formic acid (80:20, v/v). The detection was carried out by multiple-reaction monitoring mode under positive electrospray ionization. The quantification was performed using the transitions of m/z 309.1/185.0 for 1-acetoxy-6α-hydroxyeriolanolide, m/z 249.0/231.1 for 1β-hydroxyalantolactone and ivangustin and m/z 285.0/193.0 for diazepam, respectively. Calibration curves were linear over the concentration range of 4-800 ng/mL for 1-acetoxy-6α-hydroxyeriolanolide, 8-500 ng/mL for 1β-hydroxyalantolactone and ivangustin. The limit of detection (LOD) was 1 ng/mL for 1-acetoxy-6α-hydroxyeriolanolide, 1.6 ng/mL for 1β-hydroxyalantolactone and ivangustin (S/N=3). The intra-day and inter-day precisions (RSD%) for the three compounds were less than 7.8% and 8.6%, and the accuracy (RE%) ranged from -4.6 to 6.8%. The method was successfully applied to pharmacokinetic studies of the three sesquiterpene lactones after oral administration of 300 mg/kg Herba Inula extract to rats, the t(½) of 1-acetoxy-6α-hydroxyeriolanolide, 1β-hydroxyalantolactone and ivangustin was 9.65±1.43, 14.88±0.82 and 13.93±2.74 (h). The AUC((0-t)) of 1-acetoxy-6α-hydroxyeriolanolide, 1β-hydroxyalantolactone and ivangustin was 1102.46±247.04, 808.92±117.53 and 990.35±275.49 (ng h/mL), respectively.

  15. Recognition pattern of different bases in the active site of ribonuclease Ms--a model building study.

    PubMed

    Floegel, R; Zielenkiewicz, P; Saenger, W

    1989-10-01

    The structure of base non-specific ribonuclease Ms from Aspergillus saitoi was predicted by sequence similarity to guanine-specific RNase T1 of known structure. In this paper the interaction pattern of binding site of RNase Ms with different nucleic acids bases is analysed using model building and energy minimisation techniques. It is shown that unspecificity of this protein can be explained only when taking into account flexibility of the base recognition loop.

  16. A hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) based metabolomics study on colour stability of ovine meat.

    PubMed

    Subbaraj, Arvind K; Kim, Yuan H Brad; Fraser, Karl; Farouk, Mustafa M

    2016-07-01

    Meat colour is one of the cues available to the consumer to gauge overall meat quality and wholesomeness. Colour stability of meat is determined by several factors both inherent to the animal and post-slaughter conditions, including ageing, storage/packaging and display times. A hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) based metabolomics study was undertaken to identify and compare polar metabolites between ovine meat samples that were exposed to different durations of ageing, storage conditions, and display times. Primary metabolites comprising amino acids, sugars, nucleotides, nucleosides, organic acids and their breakdown products were mainly identified as discriminating factors. For the first time, boron complexes of sugar and malic acid were also tentatively identified. As expected, most compounds identified were related to myoglobin chemistry, and compounds with antioxidant properties were found in higher levels in colour stable samples. Supplementary studies identifying semi-polar, non-polar and volatile compounds will provide a holistic understanding of the chemical basis of colour stability in ovine meat.

  17. Bilirubin degradation in methanol induced by continuous UV-B irradiation: a UHPLC--ESI-MS study.

    PubMed

    Stanojević, J S; Zvezdanović, J B; Marković, D Z

    2015-04-01

    Degradation of bilirubin in aerobic methanol solution by continuous UV-B irradiation has been investigated in this work. The purpose of this study was to shed more light on bilirubin interaction with the UV-B component of natural sunlight, since bilirubin is a very efficient UV-B absorber located in the skin epidermis. The degradation products have been detected and studied by a combined method of Ultra High Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry (UHPLC-ESI-MS). Bilirubin, a toxic pigment which itself is a product of (hemoglobin) degradation in organisms, undergoes its own degradation under aerobic conditions of UV-B continuous irradiation (e.g. photooxidation) that can be partly self-sensitized. Two dipyrrolic structures have been identified as a result of the bilirubin degradation, not including the bilirubin derivative biliverdin whose increase in the irradiated system is synchronous with a time dynamics of bilirubin degradation. It appears that one of dipyrrolic products originates directly from bilirubin and biliverdin molecules, while the other one is probably connected to bilirubin self-sensitized degradation. The precursor role of biliverdin in the degradation process--related to the detected dipyrroles--has not been confirmed.

  18. Trace Element Study of MORB Glasses from 14¡ã-16¡ãN along Mid-Atlantic Ridge by LA-ICP- MS

    NASA Astrophysics Data System (ADS)

    Barzoi, C. A.; Casey, J. F.; Gao, Y.; Lapen, T.

    2007-12-01

    A comparison of 20 MORB glasses from 14°-16° N along the Mid-Atlantic Ridge using both solution-based and in situ laser ablation-based ICP-MS trace element analyses on the same samples was conducted. Li, Be, Sc, Ti, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Ba, La, Ce, Pr, Nd, Sm, Eu, Tb, Gd, Dy, Ho, Er, Tm, Yb,Lu, Hf, Ta, Pb, Th, and U were analyzed using the Varian 810 quadrupole ICP-MS. The instrument features a 90 degree ion mirror and low noise double-off-axis quadrupole that allows high sensitivity and low backgrounds. Precision in term of relative standard deviation (RSD) of the measurements for both methods based on repeated analyses of USGS BIR-1G and BHVO-2G glass standards and Max Planck KL-2G glass standard is within 5 % for all trace elements with the exception of Pb, which averaged 12 %. Measured trace element abundances are within 2% of recommended standard values using both solution and laser ablation methods. Comparison between the analyte concentrations obtained by solution-based ICP-MS and in situ microanalysis by laser ablation reveals little systematic differences in abundances(<5% for all elements). The two-method correlation and strong repeatability of the results indicate that rapid in situ trace element analysis by laser ablation ICP-MS is likely to become a preferred method of trace element analysis for MORB glasses. Our geochemical results and previous studies of MORB glasses in the region of the MAR between 14°-16°N show that basalts are characterized isotopic and incompatible element enrichment.The nature of the enrichment has been the topic of significant discussion and speculation because a specific mantle plume is not well defined in the region. Likewise the magma supply is probably small in the region as the magmatic crust is interpreted to be very thin in most of the area studied. Integrated studies of major element, trace element, and isotopic variations among basalts, gabbroic rocks and igneous and residual ultramafic

  19. A UPLC-MS/MS approach for simultaneous determination of eight flavonoids in rat plasma, and its application to pharmacokinetic studies of Fu-Zhu-Jiang-Tang tablet in rats.

    PubMed

    Tao, Yi; Chen, Xi; Jiang, Yanhui; Cai, Baochang

    2017-03-01

    The purpose of this study is to establish and validate a UPLC-MS/MS approach to determine eight flavonoids in biological samples and apply the method to pharmacokinetic study of Fu-Zhu-Jiang-Tang tablet. A Waters BEH C18 UPLC column was employed with methanol/0.1% formic acid-water as mobile phases. The mass analysis was carried out in a triple quadrupole mass spectrometer using multiple reaction monitoring with negative scan mode. A one-step protein precipitation by methanol was used to extract the analytes from blood. Eight major flavonoids were selected as markers. Our results showed that calibration curves for 3'-hydroxypuerarin, mirificin, puerarin, 3'-methoxypuerarin, daidzin, rutin, astragalin and daidzein displayed good linear regression (r(2)  > 0.9986). The intra-day and inter-day precisions (RSD) of the eight flavonoids at high, medium and low levels were <8.03% and the bias of the accuracies ranged from -5.20 to 6.75%.The extraction recoveries of the eight flavonoids were from 91.4 to 100.5% and the matrix effects ranged from 89.8 to 103.8%. The validated approach was successfully applied to a pharmacokinetic study in Sprague-Dawley rats after oral administration of FZJT tablet. Double peaks were emerged in curves of mean plasma concentration for 3'-methoxypuerarin, which was reported for the first time.

  20. Confirmation of Drug Delivery after Liver Chemoembolization: Direct Tissue Doxorubicin Measurement by UHPLC-MS-MS

    PubMed Central

    Baumgarten, Sigrid; Gaba, Ron C.; van Breemen, Richard B.

    2012-01-01

    Because liver cancer is rarely suitable for surgery, transcatheter arterial chemoembolization (TACE) is used for palliative therapy. In this procedure, an emulsion of doxorubicin in iodized oil is injected directly into liver tumors through a catheter positioned within the artery supplying blood flow to the tumor. At present, there is limited understanding of factors affecting the delivery and dispersion of doxorubicin within treated tumors during TACE. This study addresses the development and application of an ultrahigh pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS-MS) method for rapid confirmation of drug delivery after TACE in a rabbit VX2 liver cancer model. Doxorubicin levels in liver tumors were measured using UHPLC-MS-MS and compared with computed tomography measured levels of iodized oil, a metric used clinically to indicate drug delivery. We found that tissue drug levels determined using UHPLC-MS-MS did not correlate with the regional iodized oil concentration (vehicle) within tumors following TACE, suggesting that chemotherapeutic drugs like doxorubicin spread throughout tumors, and that lack of iodized oil staining in portions of a tumor does not necessarily indicate inadequate therapy during TACE. PMID:22454282

  1. Toxaphene analysis in Great Lakes fish: a comparison of GC-EI/MS/MS and GC-ECNI-MS, individual congener standard and technical mixture for quantification of toxaphene.

    PubMed

    Xia, Xiaoyan; Crimmins, Bernard S; Hopke, Philip K; Pagano, James J; Milligan, Michael S; Holsen, Thomas M

    2009-09-01

    Toxaphene is considered to be a problematic organochlorine pollutant because of its bioaccumulation potential and persistence in aquatic environments. In this study, whole lake trout and walleye composites were used to evaluate two analytical techniques for total toxaphene and selected congener analysis. The efficacy of using gas chromatography electron ionization tandem mass spectrometry (GC-EI/MS/MS) and electron capture negative ionization mass spectrometry (GC-ECNI-MS) were compared. Although the sensitivity using GC-ECNI-MS was approximately five times greater than GC-EI/MS/MS, the latter provided more consistent inter-Parlar relative response factors (RRF). When using technical calibration mixtures, these results suggest a more accurate total toxaphene measurement was obtained using the GC-EI/MS/MS method. Total toxaphene concentrations in lake trout composites from both methods were highly correlated (R(2) = 0.985) with the MS/MS concentrations approximately half of those determined by ECNI, suggesting systematic high bias in toxaphene concentrations when measured using GC-ECNI.

  2. Suicidality and interrogative suggestibility.

    PubMed

    Pritchard-Boone, Lea; Range, Lillian M

    2005-01-01

    All people are subject to memory suggestibility, but suicidal individuals may be especially so. The link between suicidality and suggestibility is unclear given mixed findings and methodological weaknesses of past research. To test the link between suicidality and interrogative suggestibility, 149 undergraduates answered questions about suicidal thoughts and reasons for living, and participated in a direct suggestibility procedure. As expected, suggestibility correlated with suicidality but accounted for little overall variance (4%). Mental health professionals might be able to take advantage of client suggestibility by directly telling suicidal persons to refrain from suicidal thoughts or actions.

  3. Development and validation a LC-MS/MS method for the simultaneous determination of agomelatine and its metabolites, 7-desmethyl-agomelatine and 3-hydroxy-agomelatine in human plasma: Application to a bioequivalence study.

    PubMed

    Li, Meizhen; Tang, Fang; Xie, Feifan; Lv, Yisha; Yu, Peng; Liu, Zhi; Cheng, Zeneng

    2015-10-15

    A novel sensitive and selective LC-MS/MS method for the determination of agomelatine, 7-desmethyl-agomelatine and 3-hydroxy-agomelatine in human plasma was developed and validated. After simple protein precipitation, the analytes were separated on a Phenomenex ODS3 column (4.6×150 mm, 5μm, Phenomenex, USA) with mobile phase consisted of methanol and 5mM ammonium formate solution (containing 0.2% formic acid) at a ratio of 70:30 (v/v) with a flow rate of 0.8mL/min. The MS acquisition was performed in multiple reactions monitoring (MRM) mode with a positive electrospray ionization source. The mass transitions monitored were m/z 244.1→185.1, m/z 230.1→171.1, m/z 260.1→201.1 and m/z 180.1→110.1 for agomelatine, 7-desmethyl-agomelatine, 3-hydroxy-agomelatine and internal standard (phenacetin), respectively. The method was validated for specificity, linearity and lower limit of quantification, precision and accuracy, extraction recovery, matrix effect and stability. The calibration curves for agomelatine, 7-desmethyl-agomelatine and 3-hydroxy-agomelatine in human plasma were linear over concentration ranges of 0.0457-100ng/mL, 0.1372-300ng/mL and 0.4572-1000ng/mL, respectively. Intra- and inter-day precisions and accuracies data met the acceptance criteria of FDA guideline for bioanalytical method validation. The developed method has been successfully applied to a bioequivalence study in healthy Chinese volunteers.

  4. Metabolic fate analysis of Huang-Lian-Jie-Du Decoction in rat urine and feces by LC-IT-MS combining with LC-FT-ICR-MS: a feasible strategy for the metabolism study of Chinese medical formula.

    PubMed

    Zuo, Ran; Ren, Wei; Bian, Bao-Lin; Wang, Hong-Jie; Wang, Yao-Nan; Hu, Hao; Zhao, Hai-Yu; Si, Nan

    2016-01-01

    1. Huang-Lian-Jie-Du Decoction (HLJDD) is widely used for the treatment of hypertension, diabetes, inflammation and neural system diseases in clinic. In the present study, the comprehensive metabolic profile of HLJDD was demonstrated reliably and rapidly followed by the metabolic pathway analysis of six typical pure compounds (four alkaloids, one flavonoid and one iridoid) in HLJDD using LC-IT-MS combined with high resolution LC-FT-ICR-MS. 2. Totally, 85 compounds, including 32 prototype components and 53 biotransformed metabolites were detected and characterized in the urine and feces after oral administration of HLJDD and six pure compounds to rats, respectively. Among them, 17 prototypes were identified definitely with standard references. 3. Hydroxylation, demethylation and glucuronidation reactions of alkaloids, as well as glucuronidation and sulfonation reactions of iridoids and flavonoids, were observed as the major metabolic pathways of HLJDD. Flavonoids, iridoids and their metabolites were mainly excreted from urine. However, amount of alkaloids were detected in feces. 4. In general, the distinctive metabolic process of three kinds of representative components in HLJDD was clarified. The in vivo metabolic network of HLJDD was demonstrated. Meanwhile, the investigation of representative pure compounds in metabolic study provided a valuable strategy to elucidate the full-scale metabolic fate of HLJDD. This might be helpful to understand the in vivo mechanism of Traditional Chinese medicine (TCM).

  5. Simultaneous determination of paeoniflorin, albiflorin, ferulic acid, tetrahydropalmatine, protopine, typhaneoside, senkyunolide I in Beagle dogs plasma by UPLC-MS/MS and its application to a pharmacokinetic study after Oral Administration of Shaofu Zhuyu Decoction.

    PubMed

    Huang, Xiaochen; Su, Shulan; Cui, Wenxia; Liu, Pei; Duan, Jin-ao; Guo, Jianming; Li, Zhenhao; Shang, Erxin; Qian, Dawei; Huang, Zhijun

    2014-07-01

    In this present study, a sensitive and rapid UPLC-MS/MS method was developed for simultaneous quantification of paeoniflorin, albiflorin, ferulic acid, tetrahydropalmatine, protopine, typhaneoside and senkyunolide I in Beagle dog plasma after oral administration of the Shao-Fu-Zhu-Yu Decoction. Chloramphenicol and clarithromycin were used as internal standards. Plasma samples were processed by protein precipitation with methanol. The separation was performed on an Acquity BEH C18 column (100mm×2.1mm, 1.7μm) at a flow-rate of 0.4mL/min, using 0.1% formic acid-acetonitrile as mobile phase. Method validation was performed as per Food and Drug Administration guidelines and the results met the acceptance criteria. After validation, this method was successfully applied to a pharmacokinetic study. The results showed that the apparent plasma clearance of paeoniflorin, albiflorin, typhaneoside and senkyunolide I were significantly higher than others. Double peak was observed in plasma concentration curves of tetrahydropalmatine, the ferulic acid had a good absorption in Beagle dog plasma, and senkyunolide I was detected in plasma from the first blood sampling time (15min) and rapidly reached Tmax. The compound of typhaneoside has a low bioavailability according to the results.

  6. A bio-analytical hydrophilic interaction LC-MS/MS method for the simultaneous quantification of omeprazole and lansoprazole in human plasma in support of a pharmacokinetic omeprazole study in children.

    PubMed

    De Smet, Julie; Boussery, Koen; De Cock, Pieter; De Paepe, Peter; Remon, Jean-Paul; Van Winckel, Myriam; Van Bocxlaer, Jan

    2010-03-01

    A hydrophilic interaction LC method with MS/MS was developed and validated for the simultaneous quantification of omeprazole and lansoprazole in human plasma. Chromatographic separation was achieved on a Betasil silica column using a high organic mobile phase (eluent A: ACN/formic acid 997.5:2.5 v/v; eluent B: water/formic acid 997.5:2.5 v/v) and gradient elution. The mass spectrometer was operated in the Multiple Reaction Monitoring mode. Prior to chromatography, liquid-liquid extraction with ethyl acetate was used and the organic layer was diluted with ACN, allowing direct injection on column. The method showed acceptable linearity, high precision (RSD%<10.5%), accuracy (88.9-109.3%) and selectivity in the two concentration ranges studied: 1.5-100 and 5-2000 ng/mL. The LOQ was established at 1.5 and 5 ng/mL for the two concentration ranges. Lack of variability in matrix effects was demonstrated and mean extraction recovery for omeprazole and lansoprazole was determined in the low (56.3-67.7%) and high (45.3-44.3%) concentration range, respectively. Additionally, plasma samples were found to be stable after three freeze-thaw cycles and for at least 15 h after extraction. This assay was successfully applied to a pharmacokinetic omeprazole study in children with cerebral palsy and mental retardation.

  7. LC-MS Based Sphingolipidomic Study on A2780 Human Ovarian Cancer Cell Line and its Taxol-resistant Strain

    PubMed Central

    Huang, Hao; Tong, Tian-Tian; Yau, Lee-Fong; Chen, Cheng-Yu; Mi, Jia-Ning; Wang, Jing-Rong; Jiang, Zhi-Hong

    2016-01-01

    Drug resistance elicited by cancer cells continue to cause huge problems world-wide, for example, tens of thousands of patients are suffering from taxol-resistant human ovarian cancer. However, its biochemical mechanisms remain unclear. Sphingolipid metabolic dysregulation has been increasingly regarded as one of the drug-resistant mechanisms for various cancers, which in turn provides potential targets for overcoming the resistance. In the current study, a well-established LC-MS based sphingolipidomic approach was applied to investigate the sphingolipid metabolism of A2780 and taxol-resistant A2780 (A2780T) human ovarian cancer cell lines. 102 sphingolipids (SPLs) were identified based on accurate mass and characteristic fragment ions, among which 12 species have not been reported previously. 89 were further quantitatively analyzed by using multiple reaction monitoring technique. Multivariate analysis revealed that the levels of 52 sphingolipids significantly altered in A2780T cells comparing to those of A2780 cells. These alterations revealed an overall increase of sphingomyelin levels and significant decrease of ceramides, hexosylceramides and lactosylceramides, which concomitantly indicated a deviated SPL metabolism in A2780T. This is the most comprehensive sphingolipidomic analysis of A2780 and A2780T, which investigated significantly changed sphingolipid profile in taxol-resistant cancer cells. The aberrant sphingolipid metabolism in A2780T could be one of the mechanisms of taxol-resistance. PMID:27703266

  8. Model studies on the oxygen-induced formation of benzaldehyde from phenylacetaldehyde using pyrolysis GC-MS and FTIR.

    PubMed

    Chu, Fong Lam; Yaylayan, Varoujan A

    2008-11-26

    Benzaldehyde, a potent aroma chemical of bitter almond, can also be formed thermally from phenylalanine and may contribute to the formation of off-aroma. To identify the precursors involved in its generation during Maillard reaction, various model systems containing phenylalanine, phenylpyruvic acid, phenethylamine, or phenylacetaldehyde were studied in the presence and absence of moisture using oxidative and nonoxidative Py-GC-MS. Analysis of the data indicated that phenylacetaldehyde, the Strecker aldehyde of phenylalanine, is the most effective precursor and that both air and water significantly enhanced the rate of benzaldehyde formation from phenylacetaldehyde. Phenylpyruvic acid was the most efficient precursor under nonoxidative conditions. Phenethylamine, on the other hand, needed the presence of a carbonyl compound to generate benzaldehyde only under oxidative conditions. On the basis of the results obtained, a free radical initiated oxidative cleavage of the carbon-carbon double bond of the enolized phenylacetaldehyde was proposed as a possible major mechanism for benzaldehyde formation, and supporting evidence was provided through monitoring of the evolution of the benzaldehyde band from heated phenylacetaldehyde in the presence and absence of 1,1'-azobis(cyclohexanecarbonitrile) on the ATR crystal of an FTIR spectrophotometer. In the presence of the free radical initiator, the enol band of the phenylacetaldehyde centered at 1684 cm(-1) formed and increased over time, and after 18 min of heating time the benzaldehyde band centered at 1697 cm(-1) formed and increased at the expense of the enol band of phenylacetaldehyde, indicating a precursor product relationship.

  9. 222 nm Photo-induced radical reactions in silazanes. A combined laser photolysis, EPR, GC-MS and QC Study.

    PubMed

    Knolle, Wolfgang; Wennrich, Luise; Naumov, Sergej; Czihal, Konstanze; Prager, Lutz; Decker, Daniel; Buchmeiser, Michael R

    2010-03-14

    The initiation mechanism of the VUV-induced conversion of polyorganosilazanes into methyl-Si-O-Si networks was studied by means of model disilazane compounds. A combined experimental approach was chosen to determine the primary radicals and their properties (lifetimes, spectra) as well as the major final products. It was verified that both Si-N and Si-CH(3) cleavage occur in the condensed phase, the former with higher yield. The lifetime of the primary Si- and N-centred radicals in de-oxygenated n-hexane solution is less than MS reveals linear R-(Si-O)(n)- chains rather than branched compounds as the initial products of the oxidative conversion of tetramethyldisilazane. It was shown that reactive silylene intermediates do not play a role in the conversion process. Quantum chemical calculations assist in the interpretation.

  10. Quantification of mesembrine and mesembrenone in mouse plasma using UHPLC-QToF-MS: Application to a pharmacokinetic study.

    PubMed

    Manda, Vamshi K; Avula, Bharathi; Ashfaq, Mohammad K; Abe, Naohito; Khan, Ikhlas A; Khan, Shabana I

    2017-03-01

    Sceletium tortuosum, is an indigenous herb of South Africa which is widely used as an herbal supplement in the treatment of anxiety and stress. Mesembrenone and mesembrine are the two main pharmacologically active alkaloids present in the extract. Despite the wide therapeutic applications of Sceletium extract, there are no reports of in vivo pharmacokinetic properties or analytical methods to quantify these two important alkaloids in plasma. Therefore, the current study aimed to develop and validate a simple and sensitive analytical method for simultaneous quantification of mesembrenone and mesembrine in mouse plasma. Ultra-high-performance liquid chromatography-mass spectrometry (UHPLC/QToF-MS) was employed to achieve our objectives. The compounds were extracted using protein precipitation by methanol (100%) with quinine as an internal standard. The lower limit of quantification for both the compounds was 10 ng/mL. The extraction recovery was between 87 and 93% for both compounds with no matrix effects on the analysis. The accuracy was between 89.5 and 106% and precision was <12.6% for all quality control samples. This validated method was successfully applied to evaluate the i.v. plasma pharmacokinetics of mesembrine and mesembrenone in mouse. However, the oral bioavailability of these alkaloids was poor and the plasma levels were below the detection limits.

  11. Catalytic fast co-pyrolysis of biomass and food waste to produce aromatics: Analytical Py-GC/MS study.

    PubMed

    Zhang, Bo; Zhong, Zhaoping; Min, Min; Ding, Kuan; Xie, Qinglong; Ruan, Roger

    2015-01-01

    In this study, catalytic fast co-pyrolysis (co-CFP) of corn stalk and food waste (FW) was carried out to produce aromatics using quantitative pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and ZSM-5 zeolite in the hydrogen form was employed as the catalyst. Co-CFP temperature and a parameter called hydrogen to carbon effective ratio (H/C(eff) ratio) were examined for their effects on the relative content of aromatics. Experimental results showed that co-CFP temperature of 600 °C was optimal for the formation of aromatics and other organic pyrolysis products. Besides, H/C(eff) ratio had an important influence on product distribution. The yield of total organic pyrolysis products and relative content of aromatics increased non-linearly with increasing H/C(eff) ratio. There was an apparent synergistic effect between corn stalk and FW during co-CFP process, which promoted the production of aromatics significantly. Co-CFP of biomass and FW was an effective method to produce aromatics and other petrochemicals.

  12. Formulation of sage essential oil (Salvia officinalis, L.) monoterpenes into chitosan hydrogels and permeation study with GC-MS analysis.

    PubMed

    Kodadová, Alexandra; Vitková, Zuzana; Herdová, Petra; Ťažký, Anton; Oremusová, Jarmila; Grančai, Daniel; Mikuš, Peter

    2015-01-01

    This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples. The experimental results revealed that the chitosan hydrogels are suitable for the formulation of sage essential oil. The monoterpene release can be effectively controlled by both chitosan and caffeine concentration in the hydrogels. Permeation experiment, based on a hydrogel with the optimized composition [3.5% (w/w) sage essential oil, 2.0% (w/w) caffeine, 2.5% (w/w) chitosan and 0.1% (w/w) Tween-80] in donor compartment, saline solution in acceptor compartment, and semi-permeable cellophane membrane, demonstrated the useful permeation selectivity. Here, (according to lipophilicity) an enhanced permeation of the bicyclic monoterpenes with antiflogistic and antiseptic properties (eucalyptol, camphor and borneol) and, at the same time, suppressed permeation of toxic thujone (not exceeding its permitted applicable concentration) was observed. These properties highlight the pharmaceutical importance of the developed chitosan hydrogel formulating sage essential oil in the dermal applications.

  13. "Afterlife experiment": use of MALDI-MS and SIMS imaging for the study of the nitrogen cycle within plants.

    PubMed

    Seaman, Callie; Flinders, Bryn; Eijkel, Gert; Heeren, Ron M A; Bricklebank, Neil; Clench, Malcolm R

    2014-10-21

    As part of a project to demonstrate the science of decay, a series of mass spectrometry imaging experiments were performed. The aim was to demonstrate that decay and decomposition are only part of the story and to show pictorially that atoms and molecules from dead plants and animals are incorporated into new life. Radish plants (Raphanus sativus) were grown hydroponically using a nutrient system containing (15)N KNO3 (98% labeled) as the only source of nitrogen. Plants were cropped and left to ferment in water for 2 weeks to create a radish "tea", which was used as a source of nitrogen for radish grown in a second hydroponics experiment. After 5 weeks of growth, the radish plants were harvested and cryosectioned, and sections were imaged by positive-ion MALDI and SIMS mass spectrometry imaging. The presence of labeled species in the plants grown using (15)N KNO3 as nutrient and those grown from the radish "tea" was readily discernible. The uptake of (15)N into a number of identifiable metabolites has been studied by MALDI-MS and SIMS imaging.

  14. A comparative study on bioactive constituents in different parts of Lonicera japonica determined by HPLC-ESI-MS(n).

    PubMed

    Wang, Ya-Dan; He, Yi; Dai, Zhong; Kang, Shuai; Zhang, Ji; Ma, Shuang-Cheng

    2016-10-01

    Lonicera japonica Thunb. is a well-known traditional herbal medicine in most East Asian countries. In China, the flower bud and stem of this plant are used for various clinical therapies, while the leaf is not officially recognized as an active part. Due to the similarities in their chemical constituents but great differences in their commercial values, the flower bud has been found to be adulterated with leaf and/or stem during the production of formulations by some drug manufactures. In order to identify adulteration in products and enable quality control, it is necessary to chemically discriminate these three parts of L. japonica. In the current study, an HPLC-ESI-MS(n) method was developed and validated for the quantitative analysis of 18 bioactive compounds: 7 organic acids, 6 iridoids, and 5 flavonoids, in batches of flower bud, stem, and leaf samples. Subsequently, chemometric analyses, such as one-way analysis of variance, principal component analysis, and hierarchical clustering analysis, were performed based on the quantitative data. The results indicated that there were remarkable differences in the distribution of the investigated compounds among the three parts of L. japonica, and that they could be straightforwardly and reliably distinguished according to their chemical profiles. Twelve compounds were selected as potential differential metabolites, which would be useful for quality control of L. japonica. As the content of caffeic acid was low in the flower bud but much higher in the stem and leaf, it could be used as a chemical marker to identify adulteration.

  15. A UHPLC-TOF/MS method based metabonomic study of total ginsenosides effects on Alzheimer disease mouse model.

    PubMed

    Gong, Yingge; Liu, Ying; Zhou, Ling; Di, Xin; Li, Wei; Li, Qing; Bi, Kaishun

    2015-11-10

    A metabonomic method was established to find potential biomarkers and study the metabolism disturbance in Alzheimer disease animal model. Total ginsenosides, as potential agent in neuroprotection and anti-inflammation, was also studied to learn the regulation mechanism to plasma metabolites in model animals. In experiment, amyloid beta 1-42 was occupied to form Alzheimer disease animal model. After drug administration, animals were evaluated by Morris water maze behavior test and sacrificed. Plasma samples were then analyzed using UHPLC-TOF/MS method to determine the endogenous metabolites. Behavior test results revealed that the spatial learning and memory abilities were deficit in model mice, and total ginsenosides could improve cognition abilities in dose-dependent manners. Principal component analysis showed that model and sham were divided into two groups, which means the metabolic network of mice was disturbed after modeling. Accordingly, 19 biomarkers were found and identified. In model group, the levels of proline, valine, tryptophan, LPC (14:0), LPC (15:0), LPC (15:1), LPC (17:0), LPC (18:2), LPC (18:3) and LPC (20:4) were up-regulated, while the levels of acetylcarnitine, palmitoylcarnitine, vaccenylcarnitine, phytosphingosine, N-eicosanoylethanolamine, hexadecenoic acid, docosahexaenoic acid, docosapentaenoic acid and octadecadienoic acid were down-regulated. The levels of these metabolites were recovered in different degrees after total ginsenosides administration. Combining with behavior study results, total ginsenosides could ameliorate both cognition symptoms and metabolic changes in model animals. This metabonomic approach provided a feasible way to understand the endogenous alterations of AD and to study the pharmacodynamic activity of novel agents.

  16. The Life of Suggestions

    ERIC Educational Resources Information Center

    Pearce, Cathie

    2010-01-01

    Using the notion of a suggestion, or rather charting the life of suggestions, this article considers the happenings of chance and embodiment as the "problems that got away." The life of suggestions helps us to ask how connectivities are made, how desire functions, and how "immanence" rather than "transcendence" can open up the politics and ethics…

  17. Validated UPLC-MS/MS method for simultaneous determination of simvastatin, simvastatin hydroxy acid and berberine in rat plasma: Application to the drug-drug pharmacokinetic interaction study of simvastatin combined with berberine after oral administration in rats.

    PubMed

    Liu, Mei; Su, Xianying; Li, Guofei; Zhao, Guilian; Zhao, Limei

    2015-12-01

    A rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method was developed and validated for simultaneous quantification of simvastatin (SV), its metabolite simvastatin hydroxy acid (SVA) and berberine (BBR) in rat plasma. Separation was performed on Poroshell 120 EC-C18 column (4.6×50mm, 2.7μm) using gradient elution by mobile phase containing acetonitrile and 10mM ammonium acetate (pH 4.5). Polarity switch (positive-negative-positive ionization mode) was performed in a total run time of 4.0min. The lower limits of quantification (LLOQ) for SV, SVA and BBR were 0.10, 0.20 and 0.10ng/mL, respectively. The response function was established for concentration range of 0.10-100ng/mL for SV and BBR and 0.20-3000ng/mL for SVA, with a coefficient of correlation of >0.99 for all the compounds. The proposed method was applied to the drug-drug pharmacokinetic interaction study of SV combined with BBR after oral administration in rats.

  18. Development of a UFLC-MS/MS method for the simultaneous determination of seven tea catechins in rat plasma and its application to a pharmacokinetic study after administration of green tea extract.

    PubMed

    Huo, Yanshuang; Zhang, Qian; Li, Qing; Geng, Bingjie; Bi, Kaishun

    2016-06-05

    A rapid, sensitive and selective ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed and validated for simultaneous determination of seven green tea catechins including catechin (C), (-)-epicatechin (EC), gallocatechin (GC), (-)-epigallocatechin (EGC), (-)-epicatechin-3-gallate (ECG), gallocatechin-3-gallate (GCG) and (-)-epigallocatechin-3-gallate (EGCG) in rat plasma. The plasma samples were firstly hydrolysed with the mixture of β-glucuronidase and sulfatase, which were then extracted by liquid-liquid extraction with ethyl acetate-isopropanol (1:1, v/v). The analytes were separated on a Venusil MP C18 column (Venusil, China) with a gradient elution at a flow rate of 0.4mL/min. The detection was performed in negative ionization and multiple reaction monitoring (MRM) mode. All the calibration curves exhibited good linearity (r>0.9943) with intra- and inter-day precisions of less than 14.3% and the accuracy deviations ranging from -8.8% to 7.5%. The extraction recoveries of the analytes and ethyl gallate (internal standard) were all more than 72%. The validated method was successfully applied to a pharmacokinetic study of seven catechins in rat plasma after oral administration of the green tea extract at different doses of 0.4, 1.2 and 2.0g/kg.

  19. Development of a highly sensitive LC-MS/MS method for simultaneous determination of rupatadine and its two active metabolites in human plasma: Application to a clinical pharmacokinetic study.

    PubMed

    Sun, Chenglong; Li, Qian; Pan, Liping; Liu, Bing; Gu, Pan; Zhang, Junying; Ding, Li; Wu, Chungyong

    2015-01-01

    An easy LC-ESI-MS/MS method was developed and validated for simultaneous determination of rupatadine (RT) and its two active metabolites, namely desloratadine (DT) and 3-hydroxydesloratadine (3-OH-DT), in human plasma. The chromatographic separation was carried out on a C18 column with gradient elution by using methanol and 10mM ammonium acetate containing 0.1% (v/v) formic acid. The lower limit of quantification (LLOQ) was 0.05, 0.035 and 0.035 ng/mL for RT, DT and 3-OH-DT, respectively. The intra- and inter-day precision of analytes were within the range of 1.0-4.7% and 2.2-12.1%, respectively. The intra- and inter-day accuracy of analytes were within the range of -7.7% to 5.2% and -4.1% to 4.8%, respectively. The method was successfully applied to a pharmacokinetic study of RT and its two metabolite DT and 3-OH-DT in healthy volunteers following single (10, 20, 40 mg) and multiple (10 mg) oral doses of rupatadine fumarate tablets.

  20. Inter-laboratory study of an LC-MS/MS method for simultaneous determination of deoxynivalenol and its acetylated derivatives, 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol in wheat.

    PubMed

    Yoshinari, Tomoya; Tanaka, Toshitsugu; Ishikuro, Eiichi; Horie, Masakazu; Nagayama, Toshihiro; Nakajima, Masahiro; Naito, Shigehiro; Ohnishi, Takahiro; Sugita-Konishi, Yoshiko

    2013-01-01

    To validate an LC-MS/MS method for simultaneous determination of deoxynivalenol (DON) and its acetylated derivatives, 3-acetyl-deoxynivalenol (3ADON) and 15-acetyl-deoxynivalenol (15ADON), in wheat using a multifunctional column, an inter-laboratory study was performed in 9 laboratories using one blank wheat sample, three spiked wheat samples (10, 50, 150 µg/kg) and one naturally contaminated wheat sample. The recoveries ranged from 98.8 to 102.6% for DON, 89.3 to 98.7% for 3ADON, and from 84.9 to 90.0% for 15ADON. The relative standard deviations for repeatability (RSDR) and reproducibility (RSDR) of DON were in the ranges of 7.2-11.3% and 9.5-22.6%, respectively. For 3ADON, the RSDR ranged from 5.3 to 9.5% and the RSDR ranged from 16.1 to 18.0%, while for 15ADON, the RSDR ranged from 6.2 to 11.2% and the RSDR ranged from 17.0 to 27.2%. The HorRat values for the three analytes ranged from 0.4 to 1.2. These results validate this method for the simultaneous determination of DON and its acetylated derivatives, 3ADON and 15ADON.

  1. Simultaneous determination of neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid and geniposide in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study after administration of Reduning injection.

    PubMed

    Wang, Yanjuan; Wen, Jing; Zheng, Weihua; Zhao, Longshan; Fu, Xiaohuan; Wang, Zhenzhong; Xiong, Zhili; Li, Famei; Xiao, Wei

    2015-01-01

    A simple, specific and sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established and validated for simultaneous determination of neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid and geniposide in rat plasma using puerarin as an internal standard (IS). Plasma samples were pretreated by a one-step direct protein precipitation procedure with acetonitrile after acidified using as little as 50 μL plasma. Chromatographic separation was performed on an Acquity BEH C18 column (100 × 2.1 mm, 1.7 µm) at a flow rate of 0.2 mL/min by a gradient elution, using 0.2% acetic acid-methanol as mobile phase. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring via electrospray ionization source with negative ion mode. Calibration curves showed good linearity (r > 0.995) over wide concentration ranges. The intra- and inter-day precisions were <15%, and the accuracy was within ±8.0%. The validated method was successfully applied to a pharmacokinetic study of the four bioactive components in rats after intravenous administration of Reduning injection.

  2. Simultaneous determination of scopoletin, psoralen, bergapten, xanthotoxin, columbianetin acetate, imperatorin, osthole and isoimperatorin in rat plasma by LC-MS/MS for pharmacokinetic studies following oral administration of Radix Angelicae Pubescentis extract.

    PubMed

    Chang, Yan-xu; Zhang, Qiu-Hong; Li, Jin; Zhang, Ling; Guo, Xin-rong; He, Jun; Zhang, Peng; Ma, Lin; Deng, Yan-ru; Zhang, Bo-li; Gao, Xiu-mei

    2013-04-15

    A rapid and sensitive bioassay based on liquid chromatography tandem mass spectrometry (LC-MS/MS) has been developed and validated for the simultaneous determination of eight coumarins in rat plasma. The liquid-liquid extraction method with ethyl acetate was used to prepare the plasma samples after addition of warfarin as an internal standard (IS). Chromatographic separation was performed on an Eclipse plus C18 column (100mm×4.6mm, 1.8μm) using gradient elution when 1mM ammonium acetate aqueous solution - acetonitrile was used as the mobile phase. The lower limit of quantitation (LLOQ) of each coumarin was lower than 2.16ngmL(-1). Intra-day and inter-day precisions were less than 15%. The accuracies were in the range of 88.9-117%. The mean recoveries of coumarins and IS were higher than 84%. The method was successfully applied to a pharmacokinetic study of eight coumarins in rats after oral administration of radix angelicae pubescentis.

  3. Determination of ampicillin in human plasma by solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) and its use in bioequivalence studies.

    PubMed

    Gonçalves, Talita Mota; Bedor, Danilo César Galindo; de Abreu, Luís Renato Pires; de Sousa, Carlos Eduardo Miranda; Rolim, Clarice M Bueno; de Santana, Davi Pereira

    2008-01-01

    A simple, fast, sensitive and selective solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method for the quantitative analysis of ampicillin (CAS 69-53-4) in human plasma was developed using amoxicillin as internal standard, and sample extraction by solid-phase extraction (SPE). Extracts were separated by reversed-phase C18 with aqueous mobile phase (acetonitrile, 80:20, v/v) with 0.1% formic acid. The method was validated and successfully applied in a bioequivalence study of capsules 500 mg of ampicillin. Using a short running time of 2.5 min, the lower limit of quantification (LLOQ) for obtained ampicillin was 0.1 microg/ml for a plasma sample of 250 microl and a recovery of 94.38% +/- 4.05. Bioequivalence between the products was determined by calculating 90% confidence intervals (CI) for the ratio of Cmax, AUC0-t and AUC0-inf values for the test and reference products, which were within the 0.80-1.25 interval proposed by FDA and EMEA. It is concluded that the two formulations are bioequivalent in their rate and extent of absorption, and thus, may be used interchangeably.

  4. Backscatter Mossbauer Spectrometer (BaMS) for extraterrestrial applications

    NASA Astrophysics Data System (ADS)

    Agresti, D. G.; Shelfer, T. D.; Pimperl, M. M.; Wills, E. L.; Shen, M. H.; Morris, R. V.

    1993-06-01

    Mossbauer spectroscopy is a nuclear gamma resonance technique particularly well suited to the study of materials that contain iron (Fe-57). It can provide information on the oxidation state of iron as well as the type and proportion of iron-containing mineral species in a sample of interest. Iron Mossbauer spectroscopy (FeMS) has been applied to samples believed to have come from Mars (SNC meteorites) and has been helpful in refining the choice among putative Martian surface materials by suggesting a likely nanophase component of the Martian regolity. FeMS spectrum of a Martial analogue material (Hawaiian palagonite) is shown; it is dominated by ferric-bearing phases and shows evidence of a nanophase component. FeMS has also been applied to lunar materials. It can be used to measure the maturity of lunar surface material and has been proposed as a prospector for lunar ilmenite, an oxygen resource mineral. Several years ago we suggested a backscatter Mossbauer spectrometer (BaMS) for a Mars rover mission. Backscatter design was selected as most appropriate for in-situ application because no sample preparation is required. Since that time, we have continued to develop the BaMS instrument in anticipation that it would eventually find a home on a NASA planetary mission. Gooding proposed BaMS as a geochemistry instrument on MESUR. More recently, an LPI workshop has recommended that BaMS be included in a three-instrument payload on the next (1996?) lunar lander.

  5. Backscatter Mossbauer Spectrometer (BaMS) for extraterrestrial applications

    NASA Technical Reports Server (NTRS)

    Agresti, D. G.; Shelfer, T. D.; Pimperl, M. M.; Wills, E. L.; Shen, M. H.; Morris, R. V.

    1993-01-01

    Mossbauer spectroscopy is a nuclear gamma resonance technique particularly well suited to the study of materials that contain iron (Fe-57). It can provide information on the oxidation state of iron as well as the type and proportion of iron-containing mineral species in a sample of interest. Iron Mossbauer spectroscopy (FeMS) has been applied to samples believed to have come from Mars (SNC meteorites) and has been helpful in refining the choice among putative Martian surface materials by suggesting a likely nanophase component of the Martian regolity. FeMS spectrum of a Martial analogue material (Hawaiian palagonite) is shown; it is dominated by ferric-bearing phases and shows evidence of a nanophase component. FeMS has also been applied to lunar materials. It can be used to measure the maturity of lunar surface material and has been proposed as a prospector for lunar ilmenite, an oxygen resource mineral. Several years ago we suggested a backscatter Mossbauer s