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  • br Results and discussion br Conclusion This study describes

    2019-11-30


    Results and discussion
    Conclusion This study describes the development of a highly sensitive on-sorbent derivatisation technique, using the novel high-surface area CMV devices, to sample methamphetamine vapour. Previous methods for air sampling for methamphetamine such as sampling cassettes have often required extended sampling times and also required the use of tedious and expensive solvent extraction and pre-concentration steps. Dynamic SPME sampling yielded promising results at former clandestine laboratories, but was only effective at high vapour concentrations of ∼40 μg m−3, and required prompt analysis (under 5 h post-sampling) [10]. While CMV sampling without derivatisation showed more than 30 times greater sensitivity for airborne methamphetamine compared to dynamic SPME, the on-sorbent derivatisation provided an additional 2.3-fold improvement in sensitivity, better reproducibility, improved chromatographic peak shape and increased the post-sampling storage time from 3 days to 5 days, allowing flexibility during field sampling.
    Declaration of interest
    Acknowledgements The authors thank Forensic and Industrial Science Ltd. for use of their Chromatoprobe. The authors also thank the University of Auckland for funding this research.
    Background Cytomegalovirus (CMV) is one of most important viral pathogens in transplant recipients. CMV infection in transplant recipients is manifested directly as CMV disease or through indirect cellular effects. Transplant-specific indirect effects include allograft injury, allograft rejection, accelerated hepatitis C virus recurrence, hepatic artery thrombosis, allograft vasculopathy, and bronchiolitis obliterans. General indirect effects include opportunistic infection, post-transplantation lymphoproliferative disorder, and cardiovascular events [1]. Therefore, antiviral prophylaxis or preemptive therapy against CMV infection is commonly used in recipients of solid-organ transplants. The risk of post-transplant CMV gpr119 agonist is dependent on the pre-transplant serostatus of donor and recipient, type of transplant, time post-transplantation, immunosuppressive regimen, usage of T-cell–depleting antibodies, age, sex, human leukocyte antigen (HLA) type, and HLA mismatch [2]. Most adults have a low risk of CMV reactivation after transplantation because of prior exposure to the virus. However, CMV reactivation is still observed at high rates after transplantation. To predict which patient will develop CMV disease, CMV-specific cell-mediated immunity can be evaluated using Quantiferon-CMV, ELISpot assays, cytokine profiling, intracellular cytokine staining, tetramer staining, and adenosine triphosphate release assays [2]. The most commonly used tests are Quantiferon-CMV and ELISpot assay. Quantiferon-CMV is an enzyme-linked immunosorbent assay that detects CMV-specific CD8+ T cells, and ELIspot is an enzyme-linked immunosorbent spot-based assay that detects CMV-specific CD4+ and CD8+ T cells.
    Materials and methods
    Results A total of 32 patients with liver transplantation were enrolled, and their characteristics are shown in Table 1. Two patients died of sepsis. Four patients suffered acute cellular rejection within 1 month, and one patient 4 months, after transplantation. All patients were positive for CMV IgG, and one patient were positive for CMV IgM before transplantation. Two patients with equivocal and positive results for CMV IgM showed CMV viremia after transplantation. The correlation between CMVspot results and CMV viremia is shown in Table 2. Neither total interpretation, pp65 only, nor IE-1 only could predict viremia, and no significant difference in viremia-free survival was observed (Fig. 1). However, patients that were positive or borderline for IE-1 did not show viremia starting two months after transplantation (p = .041). The diagnostic performance of the CMVspot assay is shown in Table 3. CMVspot showed 100% specificity and 11.76% sensitivity for prediction of CMV viremia. In addition, the sensitivity of IE-1 to predict viremia starting 2 months after transplantation was 100%.