335 research outputs found

    Quantifying Isoniazid Levels in Small Hair Samples: A Novel Method for Assessing Adherence during the Treatment of Latent and Active Tuberculosis.

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    BackgroundTuberculosis (TB) is the leading cause of death from an infectious pathogen worldwide and the most prevalent opportunistic infection in people living with HIV. Isoniazid preventive therapy (IPT) reduces the incidence of active TB and reduces morbidity and mortality in HIV-infected patients independently of antiretroviral therapy. However, treatment of latent or active TB is lengthy and inter-patient variability in pharmacokinetics and adherence common. Current methods of assessing adherence to TB treatment using drug levels in plasma or urine assess short-term exposure and pose logistical challenges. Drug concentrations in hair assess long-term exposure and have demonstrated pharmacodynamic relevance in HIV.MethodsA large hair sample from a patient with active TB was obtained for assay development. Methods to pulverize hair and extract isoniazid were optimized and then the drug detected by liquid chromatography/ tandem mass spectrometry (LC/MS-MS). The method was validated for specificity, accuracy, precision, recovery, linearity and stability to establish the assay's suitability for therapeutic drug monitoring (TDM). Hair samples from patients on directly-observe isoniazid-based latent or active TB therapy from the San Francisco Department of Public Health TB clinic were then tested.ResultsOur LC/MS-MS-based assay detected isoniazid in quantities as low as 0.02ng/mg using 10-25 strands hair. Concentrations in spiked samples demonstrated linearity from 0.05-50ng/mg. Assay precision and accuracy for spiked quality-control samples were high, with an overall recovery rate of 79.5%. In 18 patients with latent or active TB on treatment, isoniazid was detected across a wide linear dynamic range.ConclusionsAn LC-MS/MS-based assay to quantify isoniazid levels in hair with performance characteristics suitable for TDM was developed and validated. Hair concentrations of isoniazid assess long-term exposure and may be useful for monitoring adherence to latent or active TB treatment in the setting of HIV

    Environmental Monitoring of Water Quality as a Planning and Management Tool: A Case Study of the Rodrigo de Freitas Lagoon, Rio de Janeiro, Brazil

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    The Rodrigo de Freitas Lagoon is an urban water body, representing one of the most popular spots for the local community. It underwent serious environmental degradation, at first through its water mirror reduction and more recently through sewer inflows. Concurrently, the difficulty in renewing the water combined with adverse climatic conditions has repeatedly led to an alarming fish mortality rate. The monitoring of its water quality has been carried out as a management and planning tool that lead to the improvement of the environmental conditions. This study seeks to assess monitoring results by correlating the factors that might be the cause of a failure to comply with environmental regulations. Although it is evident that particular places in the Lagoon might be more often affected by illegal sewer discharges, no evidence could be found of any variations between the six sampling points. However, the rise in the levels of Escherichia coli, nitrogen and phosphorus, and the general temperature conditions, pH, and salinity of the water shows that the most significant alterations occurred in spring 2018.The complexity of the period of phytoplankton growth followed by the fish mortality from anoxia underlines the need for monitoring as a tool for a better understanding of the alterations, providing guidance with regard to the planning and management of the ecosystem

    Isoniazid concentrations in hair and plasma area-under-the-curve exposure among children with tuberculosis.

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    We measured hair and plasma concentrations of isoniazid among sixteen children with tuberculosis who underwent personal or video-assisted directly observed therapy and thus had 100% adherence. This study therefore defined typical isoniazid exposure parameters after two months of treatment among fully-adherent patients in both hair and plasma (plasma area under the concentration-time curve, AUC, estimated using pharmacokinetic data collected 0, 2, 4, and 6 hours after drug administration). We found that INH levels in hair among highly-adherent individuals did not correlate well with plasma AUC or trough concentrations, suggesting that each measure may provide incremental and complementary information regarding drug exposure in the context of TB treatment
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