Israel experienced an outbreak of wild poliovirus type 1 (WPV1) in 2013–2014, detected through environmental surveillance of the sewage system. No cases of acute flaccid paralysis were reported, and ...the epidemic subsided after a bivalent oral polio vaccination (bOPV) campaign. As we approach global eradication, polio will increasingly be detected only through environmental surveillance. We developed a framework to convert quantitative polymerase chain reaction (qPCR) cycle threshold data into scaled WPV1 and OPV1 concentrations for inference within a deterministic, compartmental infectious disease transmission model. We used this approach to estimate the epidemic curve and transmission dynamics, as well as assess alternate vaccination scenarios. Our analysis estimates the outbreak peaked in late June, much earlier than previous estimates derived from analysis of stool samples, although the exact epidemic trajectory remains uncertain. We estimate the basic reproduction number was 1.62 (95% CI 1.04–2.02). Model estimates indicate that 59% (95% CI 9–77%) of susceptible individuals (primarily children under 10 years old) were infected with WPV1 over a little more than six months, mostly before the vaccination campaign onset, and that the vaccination campaign averted 10% (95% CI 1–24%) of WPV1 infections. As we approach global polio eradication, environmental monitoring with qPCR can be used as a highly sensitive method to enhance disease surveillance. Our analytic approach brings public health relevance to environmental data that, if systematically collected, can guide eradication efforts.
Purpose
Inflammation-related changes in pharmacokinetics have been described for a number of disease-states including cancer, infection, and autoimmune disorders. This study examined the impact of ...chronic hepatitis C infection (CHC) on the pharmacokinetics of the cytochrome P450 3A probe midazolam in patients without significant liver disease who were either treatment naïve or prior interferon null-responders.
Methods
Data were pooled from three studies which compared the pharmacokinetics of oral midazolam in healthy volunteers (
n
= 107) and in treatment-naive patients (
n
= 35) and interferon-null responders (
n
= 24) with CHC but without significant liver disease. Oral midazolam was administered as a single 2 mg oral dose, followed by frequent pharmacokinetic sampling and determination of the pharmacokinetics of midazolam and its α-hydroxy metabolite. CYP3A activity was determined by the metabolic ratio (MR) of the AUC metabolite/AUC parent and compared across groups as the mean effect ratio (test/reference).
Results
The midazolam MR was lower in treatment-naïve patients with CHC than in health volunteers with a mean effect ratio of 0.63 90 % confidence interval (CI) 0.56–0.72. The effect was more pronounced in null-responders, who demonstrated a mean MR effect ratio of 0.46 (90 % CI 0.39–0.53) compared to volunteers. The mean area under the concentration–time curve (AUC
inf
) for midazolam in healthy volunteers, naïve patients, and null-responders was 32.3 coefficient of variation (CV%) 41, 36.5 (CV% 33.5), and 55.3 (CV% 36.9) ng.h/mL, respectively.
Conclusions
The results of this study demonstrate a reduction in CYP3A4 activity between healthy volunteers and patients with CHC, with interferon null-responders demonstrating the most substantial difference. These results may have implications for the pharmacotherapy of patients infected with CHC.
Environmental pathogen surveillance is a sensitive tool that can detect early-stage outbreaks, and it is being used to track poliovirus and other pathogens. However, interpretation of longitudinal ...environmental surveillance signals is difficult because the relationship between infection incidence and viral load in wastewater depends on time-varying shedding intensity. We developed a mathematical model of time-varying poliovirus shedding intensity consistent with expert opinion across a range of immunization states. Incorporating this shedding model into an infectious disease transmission model, we analysed quantitative, polymerase chain reaction data from seven sites during the 2013 Israeli poliovirus outbreak. Compared to a constant shedding model, our time-varying shedding model estimated a slower peak (four weeks later), with more of the population reached by a vaccination campaign before infection and a lower cumulative incidence. We also estimated the population shed virus for an average of 29 days (95% CI 28-31), longer than expert opinion had suggested for a population that was purported to have received three or more inactivated polio vaccine (IPV) doses. One explanation is that IPV may not substantially affect shedding duration. Using realistic models of time-varying shedding coupled with longitudinal environmental surveillance may improve our understanding of outbreak dynamics of poliovirus, SARS-CoV-2, or other pathogens.
The series Religion and Society (RS) contributes to the exploration of religions as social systems– both in Western and non-Western societies; in particular, it examines religions in their ...differentiation from, and intersection with, other cultural systems, such as art, economy, law and politics. Due attention is given to paradigmatic case or comparative studies that exhibit a clear theoretical orientation with the empirical and historical data of religion and such aspects of religion as ritual, the religious imagination, constructions of tradition, iconography, or media. In addition, the formation of religious communities, their construction of identity, and their relation to society and the wider public are key issues of this series.
Thrombopoietin (TPO), the ligand for c-mpl, stimulates proliferation of committed megakaryocytic progenitors and induces maturation of megakaryocytes. To better understand factors regulating TPO ...levels, we measured blood levels of TPO in patients with impaired platelet production due to aplastic anemia (AA) and with platelet destructive disorders, including idiopathic thrombocytopenic purpura (ITP), posttransfusion purpura (PTP), drug purpura (DP), and X-linked thrombocytopenia (XLTP). The TPO receptor capture enzyme immunoassay (EIA) used had a detection limit of integral of approximately-150 to 200 pg/mL. TPO was undetectable in 88 of 89 normal individuals. Eighteen of 19 patients with AA and a mean platelet count (MPC) of 18,000/microliters (2,000 to 61,000/microliters) had markedly elevated TPO levels (mean, 1,467 pg/mL; range, 597 to 3,834 pg/mL). Eight AA patients who responded to immunosuppressive therapy with their MPC increasing to 140,000/microliters (92,000 to 175,000/microliters) had substantial decreases in TPO (mean, 440 pg/mL; range, 193 to 771 pg/mL). Initial TPO levels did not differ significantly between responders and nonresponders. In contrast, all 21 patients with ITP and an MPC of 16,000/microliters (1,000 to 51,000 /microliters) had undetectable TPO levels, as did 6 patients with acute PTP or DP and 2 patients with XLTP. Megakaryocyte mass, reflected in the rate of platelet production, appears to be the major determinant of TPO levels in thrombocytopenic patients rather than circulating platelet levels per se. Measurement of serum TPO may be useful in differentiating thrombocytopenias due to peripheral destruction from those due to thrombopoietic failure.
Background. Maximum suppression of virus replication is often not achievable for persons infected with multidrug-resistant human immunodeficiency virus type 1 (HIV-1). Available data suggest that ...lamivudine contributes to partial viral suppression, despite the presence of M184V mutations and high-level phenotypic lamivudine resistance. Methods. Selective lamivudine withdrawal was studied in 6 subjects who had incomplete viral suppression during antiretroviral treatment for multidrug-resistant HIV-1 infection. Results. Plasma levels of HIV-1 RNA increased to 0.5 log10 copies/mL above baseline 6 weeks after the withdrawal of lamivudine treatment (P = .04), even though reversion of lamivudine resistance was not yet detected. Early increases in plasma levels of HIV-1 RNA after lamivudine withdrawal were associated with the presence of the T215Y/F mutation and broad phenotypic resistance to nucleoside reverse-transcriptase inhibitors at baseline. Genotypic and phenotypic reversion of lamivudine resistance was detected in 4 subjects 8–14 weeks after withdrawal of lamivudine therapy. The duration of lamivudine withdrawal ranged from 8 to 22 weeks; all subjects resumed lamivudine treatment. Plasma levels of HIV-1 RNA were 0.6 log10 copies/mL above baseline (P = .03) when lamivudine therapy was resumed. After the resumption of lamivudine treatment, plasma HIV RNA levels decreased to baseline levels in 3 subjects but remained elevated in 3 subjects who had evolution of increased antiretroviral drug resistance during the period of lamivudine withdrawal. Safety concerns raised by this latter finding led to permanent closure of the study. Conclusions. In select cases of multidrug-resistant HIV-1 infection, lamivudine contributes to suppression of HIV-1 replication, despite the presence of M184V mutations and lamivudine resistance.
Dietary supplements containing black cohosh are alternatives to conventional hormone replacement therapy in menopause. This study investigates the maximum tolerated dose of a 75% ethanol extract of ...black cohosh and determines the pharmacokinetics of one of its most abundant triterpene glycosides, 23‐epi‐26‐deoxyactein. Single doses of black cohosh extract containing 1.4, 2.8, or 5.6 mg of 23‐epi‐26‐deoxyactein were administered to 15 healthy, menopausal women. Serial blood samples and 24‐h urine samples were obtained; blood chemistry, hormonal levels, and 23‐epi‐26‐deoxyactein levels were determined. No acute toxicity or estrogenic hormone effects were observed. Pharmacokinetic analyses of 23‐epi‐26‐deoxyactein in sera indicated that the maximum concentration and area under the curve increased proportionately with dosage, and that the half‐life was ~2 h for all dosages. Less than 0.01% of the 23‐epi‐26‐deoxyactein was recovered in urine 24 h after administration. No phase I or phase II metabolites were observed either in clinical specimens or in vitro.
Clinical Pharmacology & Therapeutics (2010) 87 2, 219–225. doi:10.1038/clpt.2009.251
Salvage therapy with efavirenz is often ineffective in patients having failed nevirapine treatment, even when mutations associated with efavirenz resistance are not detected by standard ...population-based genotyping. The presence of minority viral populations expressing efavirenz cross-resistance could explain these observations, and such populations were sought in plasma from patients failing nevirapine for whom genotyping revealed the presence of the Y181C mutation (usually associated with limited efavirenz cross-resistance) but not the K103N mutation (which produces high-level efavirenz resistance). Viral populations expressing K103N (>1% total virus) were detected by sequence-selective polymerase chain reaction in 4 of 16 patients failing nevirapine, although, in retrospect, the mutation was not perceptible in the original genotype in only 2 cases. Both patients with detectable K103N mutations whoreceived efavirenz failed treatment, and virus expressing K103N emerged. Four of 5 patients without detectable K103N mutations also failed efavirenz, associated with the emergence of nonnucleoside reverse transcriptase mutations that included K103N in 2 cases. The emergence of a minority viral population expressing K103N was identified in 1 patient from a separate study group subsequent to discontinuing treatment with nevirapine. These findings support the idea that minority viral populations with distinct resistance genotypes, although undetectable by standard genotyping, can contribute to the failure of salvage regimens.
The dynamics of emerging nucleoside and nucleotide reverse-transcriptase inhibitor (NRTI) resistance in hepatitis B virus (HBV) are not well understood because standard dideoxynucleotide direct ...polymerase chain reaction (PCR) sequencing assays detect drug-resistance mutations only after they have become dominant. To obtain insight into NRTI resistance, we used a new sequencing technology to characterize the spectrum of low-prevalence NRTI-resistance mutations in HBV obtained from 20 plasma samples from 11 NRTI-treated patients and 17 plasma samples from 17 NRTI-naive patients, by using standard direct PCR sequencing and ultra-deep pyrosequencing (UDPS). UDPS detected drug-resistance mutations that were not detected by PCR in 10 samples from 5 NRTI-treated patients, including the lamivudine-resistance mutation V173L (in 5 samples), the entecavir-resistance mutations T184S (in 2 samples) and S202G (in 1 sample), the adefovir-resistance mutation N236T (in 1 sample), and the lamivudine and adefovir–resistance mutations V173L, L180M, A181T, and M204V (in 1 sample). G-to-A hypermutation mediated by the apolipoprotein B mRNA editing enzyme, catalytic polypeptide–like family of cytidine deaminases was estimated to be present in 0.6% of reverse-transcriptase genes. Genotype A coinfection was detected by UDPS in each of 3 patients in whom genotype G virus was detected by direct PCR sequencing. UDPS detected low-prevalence HBV variants with NRTI-resistance mutations, G-to-A hypermutation, and low-level dual genotype infection with a sensitivity not previously possible
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