Browsing by Subject "Gas chromatography-mass spectrometry"

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    Association of Cannabis Use With Nausea and Vomiting of Pregnancy
    (Wolters Kluwer, 2022) Metz, Torri D.; Allshouse, Amanda A.; McMillin, Gwendolyn A.; Silver, Robert M.; Smid, Marcela C.; Haas, David M.; Simhan, Hyagriv N.; Saade, George R.; Grobman, William A.; Parry, Samuel; Chung, Judith H.; Jarlenski, Marian P.; Obstetrics and Gynecology, School of Medicine
    Our objective was to evaluate whether cannabis use was associated with nausea and vomiting in early pregnancy. Participants from nuMoM2b (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be) enrolled from October 2010 through September 2013 with a PUQE (Pregnancy-Unique Quantification of Emesis) questionnaire and an available stored urine sample from the first study visit (median gestational age 12 weeks) were included. Cannabis exposure was ascertained by urine immunoassay for 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH); positive results were confirmed with liquid chromatography tandem mass spectrometry. The primary outcome was moderate-to-severe nausea by the PUQE score. Overall, 9,250 participants were included, and 5.8% (95% CI 5.4-6.3%) had detectable urine THC-COOH. In adjusted analyses, higher THC-COOH levels were associated with greater odds of moderate-to-severe nausea (20.7% in the group with THC-COOH detected vs 15.5% in the group with THC-COOH not detected, adjusted odds ratio 1.6, 95% CI 1.1-2.2 for a 500 ng/mg Cr THC-COOH increment).
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    Monitoring compositional changes of the lipid fraction of fingermark residues deposited on paper during storage
    (Forensic Chemistry, 2016-11-01) Frick, A.A.; Chidlow, G.; Goodpaster, John V.; Lewis, S.W.; van Bronswijk, W.
    Characterising the changes in fingermark composition as a function of time is of great value for improving fingermark detection capabilities by understanding the processes and circumstances under which target compounds become degraded. In this study, gas chromatography-mass spectrometry was used to monitor relative changes in the lipids from latent fingermarks over 28 days. Principal component analysis of the relative composition of 15 lipids in fingermarks showed that fingermark age was a significant contributor to the variability observed in the data, but that inter-donor variability was also significant. This was attributed principally to changes in the relative amounts of squalene, which rapidly decreased in the fingermarks. It was also observed, however, that most fingermarks exhibited relatively small changes in composition during the first seven days, followed by more rapid changes up to 28 days. Significant inter-donor variation of both initial fingermark composition and the rates and nature of loss processes was observed, which was reflected in the relative projection of samples from different donors. Finally, samples stored with no exposure to light or airflow for 28 days were projected significantly closer to the samples analysed on the day of deposition than those exposed to light, due to the reduced photodegradation rate of squalene.
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    A Potential Biofilm Metabolite Signature for Caries Activity - A Pilot Clinical Study
    (OMICS Publishing Group, 2015-03) Zandona, F.; Soini, H. A.; Novotny, M. V.; Santiago, E.; Eckert, G. J.; Preisser, J. S.; Benecha, H. K.; Arthur, R. A.; Zero, D. T.; Department of Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    BACKGROUND: This study's aim was to compare the dental biofilm metabolite-profile of caries-active (N=11) or caries-free (N=4) children by gas chromatography-mass spectrometry (GC/MS) analyses. METHODS: Samples collected after overnight fasting, with or without a previous glucose rinse, were combined for each child based on the caries status of the site, re-suspended in ethanol and analyzed by GC/MS. RESULTS: Biofilm from caries-active sites exhibited a different chromatographic profile compared to caries-free sites. Qualitative and quantitative analysis suggested a special cluster of branched alcohols and esters present at substantially higher intensity in biofilms of caries-active sites. CONCLUSIONS: This pilot study indicates that there are metabolites present in the biofilm which have the potential to provide a characteristic metabolomics signature for caries activity.
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    Urinary Volatile Organic Compounds for Detection of Breast Cancer and Monitoring Chemical and Mechanical Cancer Treatments in Mice
    (2019-05) Teli, Meghana; Yokota, Hiroki; Agarwal, Mangilal; Ji, Julie
    The aim of this study is to identify metabolic transformations in breast cancer through urinary volatile organic compounds in mammary pad or bone tumor mice models. Subsequently, it focuses on investigating the efficacy of therapeutic intervention through identified potential biomarkers. Methods for monitoring tumor development and treatment responses have technologically advanced over the years leading to significant increase in percent survival rates. Although these modalities are reliable, it would be beneficial to observe disease progression from a new perspective to gain greater understanding of cancer pathogenesis. Analysis of cellular energetics affected by cancer using bio-fluids can non-invasively help in prognosis and selection of treatment regimens. The hypothesis is altered profiles of urinary volatile metabolites is directly related to disrupted metabolic pathways. Additionally, effectiveness of treatments can be indicated through changes in concentration of metabolites. In this ancillary experiment, mouse urine specimens were analyzed using gas chromatography-mass spectrometry, an analytical chemistry tool in identifying volatile organic compounds. Female BALB/c mice were injected with 4T1.2 murine breast tumor cells in the mammary fat pad. Consecutively, 4T1.2 cells were injected in the right iliac artery of BALB/c mice and E0771 tumor cells injected in the tibia of C57BL/6 mice to model bone tumor. The effect of two different modes of treatment: chemical drug and mechanical stimulation was investigated through changes in compound profiles. Chemical drug therapy was conducted with dopamine agents, Triuoperazine, Fluphenazine and a statin, Pitavastatin. Mechanical stimulation included tibia and knee loading at the site of tumor cell injection were given to mice. A biological treatment mode included administration of A5 osteocyte cell line. A set of potential volatile organic compounds biomarkers differentiating mammary pad or bone confined tumors from healthy controls was identified using forward feature selection. Effect of treatments was demonstrated through hierarchical heat maps and multivariate data analysis. Compounds identified in series of experiments belonged to the class of terpenoids, precursors of cholesterol molecules. Terpene synthesis is a descending step of mevalonate pathway suggesting its potential role in cancer pathogenesis. This thesis demonstrates the ability of urine volatilomics to indicate signaling pathways inflicted in tumors. It proposes a concept of using urine to detect tumor developments at two distinct locations as well as to monitor treatment efficacy.