161 research outputs found

    (2E)-2-(2,4-Dichloro­phenyl­sulfon­yl)-3-(4-methyl­anilino)-3-(methyl­sulfan­yl)acrylonitrile

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    The title compound, C17H14Cl2N2O2S2, and the 3-methoxy­anilino analogue reported in the preceding paper have been used as starting materials to develop benzothia­zine derivatives with anti­malarial activity. The mol­ecule displays an E (trans) configuration about the central double bond. Due to conjugation in the C=C—C N group, the putative single bond shows a significant shortening [1.418 (3) Å]. The mol­ecule has a six-membered ring involving an intra­molecular N—H⋯O(sulfon­yl) bond, which is an example of resonance-assisted hydrogen bonding. In the crystal structure, bonds of the C—H⋯O(sulfon­yl) and C—H⋯N(cyano) types form double layers of mol­ecules parallel to (01). Within these layers there are π–π inter­actions between benzene rings of pairs of centrosymmetrically related mol­ecules, with distances of 3.7969 (12) Å between centroids. C—H⋯π interactions are also present

    Extracellular DNA secreted in yeast cultures is metabolism-specific and inhibits cell proliferation

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    Extracellular DNA (exDNA) can be actively released by living cells and different putative functions have been attributed to it. Further, homolo-gous exDNA has been reported to exert species-specific inhibitory effects on several organisms. Here, we demonstrate by different experimental evidence, including 1H-NMR metabolomic fingerprint, that the growth rate decline in Saccharomyces cerevisiae fed-batch cultures is determined by the accumula-tion of exDNA in the medium. Sequencing of such secreted exDNA represents a portion of the entire genome, showing a great similarity with extrachromo-somal circular DNA (eccDNA) already reported inside yeast cells. The recov-ered DNA molecules were mostly single strands and specifically associated to the yeast metabolism displayed during cell growth. Flow cytometric analysis showed that the observed growth inhibition by exDNA corresponded to an arrest in the S phase of the cell cycle. These unprecedented findings open a new scenario on the functional role of exDNA produced by living cells

    Characterization of the Population Pharmacokinetics of Ampicillin in Neonates Using an Opportunistic Study Design

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    ABSTRACT Although ampicillin is the most commonly used drug in neonates, developmental pharmacokinetic (PK) data to guide dosing are lacking. Ampicillin is primarily renally eliminated, and developmental changes are expected to influence PK. We conducted an open-label, multicenter, opportunistic, prospective PK study of ampicillin in neonates stratified by gestational age (GA) (≤34 or >34 weeks) and postnatal age (PNA) (≤7 or >7 days). Drug concentrations were measured by tandem mass spectrometry. PK data were analyzed using population nonlinear mixed-effects modeling in NONMEM 7.2. Monte Carlo simulations were conducted to determine the probability of target attainment for the time in which the total steady-state ampicillin concentrations remained above the MIC ( T >MIC) for 50%, 75%, and 100% of the dosing interval. A total of 142 PK samples from 73 neonates were analyzed (median [range] GA, 36 [24 to 41] weeks; PNA, 5 [0 to 25] days). The median ampicillin dose was 200 (100 to 350) mg/kg/day. Postmenstrual age and serum creatinine were covariates for ampicillin clearance (CL). A simplified dosing regimen of 50 mg/kg every 12 h for GA of ≤34 weeks and PNA of ≤7 days, 75 mg/kg every 12 h for GA of ≤34 weeks and PNA of ≥8 and ≤28 days, and 50 mg/kg every 8 h for GA of >34 weeks and PNA of ≤28 days achieved the prespecified surrogate efficacy target in 90% of simulated subjects. Ampicillin CL was associated with neonatal development. A simplified dosing regimen stratified by GA and PNA achieves the desired surrogate therapeutic target in the vast majority of neonates

    Phage therapy is effective against infection by Mycobacterium ulcerans in a murine footpad model

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    Author Summary: Buruli Ulcer (BU), caused by Mycobacterium ulcerans, is a necrotizing disease of the skin, subcutaneous tissue and bone. Standard treatment of BU patients consists of a combination of the antibiotics rifampicin and streptomycin for 8 weeks. However, in advanced stages of the disease, surgical resection of the destroyed skin is still required. The use of bacterial viruses (bacteriophages) for the control of bacterial infections has been considered as an alternative or a supplement to antibiotic chemotherapy. By using a mouse model of M. ulcerans footpad infection, we show that mice treated with a single subcutaneous injection of the mycobacteriophage D29 present decreased footpad pathology associated with a reduction of the bacterial burden. In addition, D29 treatment induced increased levels of IFN-γ and TNF in M. ulcerans -infected footpads, correlating with a predominance of a mononuclear infiltrate. These findings suggest the potential use of phage therapy in BU, as a novel therapeutic approach against this disease, particularly in advanced stages where bacteria are found primarily in an extracellular location in the subcutaneous tissue, and thus immediately accessible by lytic phages.This work was supported by a grant from the Health Services of Fundacao Calouste Gulbenkian, and the Portuguese Science and Technology Foundation (FCT) fellowships SFRH/BPD/64032/2009, SFRH/BD/41598/2007, and SFRH/BPD/68547/2010 to GT, TGM, and AGF, respectively. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Use of Opportunistic Clinical Data and a Population Pharmacokinetic Model to Support Dosing of Clindamycin for Premature Infants to Adolescents

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    Clindamycin is commonly prescribed to treat children with skin and skin structure infections (including those caused by community-acquired methicillin-resistant Staphylococcus aureus [CA-MRSA]), yet little is known about the pharmacokinetics (PK) across pediatric age groups. A population PK analysis was performed in NONMEM using samples collected in an opportunistic study from children receiving intravenous clindamycin per standard of care. The final model was used to optimize pediatric dosing to match adult exposure proven effective against CA-MRSA. A total of 194 plasma PK samples collected from 125 children were included in the analysis. Median age (range) was 3.3 years (0–20). Median dosing was 9.9 mg/kg/dose (3.8–15.1). A 1-compartment model described the data well. The final model included body weight and a sigmoidal maturation relationship between postmenstrual age (PMA) and clearance (CL): CL (L/h)=13.7*(weight/70)0.75*(PMA3.1/(43.63.1+PMA3.1)); V (L)=61.8*(weight/70). Maturation reached 50% adult CL values at ~44 weeks PMA. Our findings support age-based dosing

    Etravirine pharmacokinetics in HIV-infected pregnant women

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    __Background__ The study goal was to describe etravirine pharmacokinetics during pregnancy and postpartum in HIV-infected women. __Methods__ IMPAACT P1026s and PANNA are on-going, non-randomized, open-label, parallel-group, multi-center phase-IV prospective studies in HIV-infected pregnant women. Intensive steady-state 12-h pharmacokinetic profiles were performed from 2nd trimester through postpartum. Etravirine was measured at two labs using validated ultra performance liquid chromatography (detection limits: 0.020 and 0.026 mcg/mL). __Results__ Fifteen women took etravirine 200 mg twice-daily. Etravirine AUC0-12 was higher in the 3rd trimester compared to paired postpartum data by 34% (median 8.3 vs. 5.3 mcg*h/mL, p = 0.068). Etravirine apparent oral clearance was significantly lower in the 3rd trimester of pregnancy compared to paired postpartum data by 52% (median 24 vs. 38 L/h, p = 0.025). The median ratio of cord blood to maternal plasma concentration at delivery was 0.52 (range: 0.19-4.25) and no perinatal transmission occurred. __Conclusion__ Etravirine apparent oral clearance is reduced and exposure increased during the third trimester of pregnancy. Based on prior dose-ranging and safety data, no dose adjustment is necessary for maternal health but the effects of etravirine in utero are unknown. Maternal health and infant outcomes should be closely monitored until further infant safety data are available. __Clinical Trial registration:__ The IMPAACT protocol P1026s and PANNA study are registered at ClinicalTrials.gov under NCT00042289 and NCT00825929

    Innate Immune Function in Placenta and Cord Blood of Hepatitis C – Seropositive Mother-Infant Dyads

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    Vertical transmission accounts for the majority of pediatric cases of hepatitis C viral (HCV) infection. In contrast to the adult population who develop persistent viremia in ∼80% of cases following exposure, the rate of mother-to-child transmission (2–6%) is strikingly low. Protection from vertical transmission likely requires the coordination of multiple components of the immune system. Placenta and decidua provide a direct connection between mother and infant. We hypothesized that innate immune responses would differ across the three compartments (decidua, placenta and cord blood) and that hepatitis C exposure would modify innate immunity in these tissues. The study was comprised of HCV-infected and healthy control mother and infant pairs from whom cord blood, placenta and decidua were collected with isolation of mononuclear cells. Multiparameter flow cytometry was performed to assess the phenotype, intracellular cytokine production and cytotoxicity of the cells. In keeping with a model where the maternal-fetal interface provides antiviral protection, we found a gradient in proportional frequencies of NKT and γδ-T cells being higher in placenta than cord blood. Cytotoxicity of NK and NKT cells was enhanced in placenta and placental NKT cytotoxicity was further increased by HCV infection. HCV exposure had multiple effects on innate cells including a decrease in activation markers (CD69, TRAIL and NKp44) on NK cells and a decrease in plasmacytoid dendritic cells in both placenta and cord blood of exposed infants. In summary, the placenta represents an active innate immunological organ that provides antiviral protection against HCV transmission in the majority of cases; the increased incidence in preterm labor previously described in HCV-seropositive mothers may be related to enhanced cytotoxicity of NKT cells
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