Accumulation of Major Linezolid Metabolites in Patients with Renal Impairment.

In patients with renal impairment (n = 22 of 39), the median serum concentrations of linezolid, PNU-142300, and PNU-142586 were 1.6-, 3.3-, 2.8-fold higher, respectively, than in patients without renal impairment. Metabolite concentrations in paired samples were poorly correlated with linezolid concentrations (r2 = 0.26 for PNU-142300 and 0.06 for PNU-142586). Linezolid and its metabolites share potential toxicophores that deserve characterization to mitigate higher myelosuppression risk in patients with renal impairment.

Pazopanib with low fat meal (PALM) in advanced renal cell carcinoma.

Background Pazopanib is approved for metastatic renal cell carcinoma (RCC). We assessed the safety and efficacy of pazopanib with a low fat meal (LFM): <400 cal and < 20% fat or 10 g per meal. Methods A single arm study of pazopanib with a LFM in 16 adult patients with metastatic RCC with a clear cell component, RECIST 1.1 measurable disease, ECOG PS ≤ 2, and ≤ 3 prior therapies. Pazopanib at 400 mg daily given with LFM for 12 weeks. Incremental dose increases up to 800 mg, or irreversible decreases to 200 mg, allowed every 2 weeks. Primary study endpoint was safety; adverse events (AE) measured per CTCAE version 4.0. Secondary endpoints of RECIST 1.1 response with assessment as 12 weeks; pharmacokinetic (PK) analysis at nine time points, and CYP3A4 polymorphism evaluation. Results Pazopanib with a LFM was well tolerated; 13 of 16 subjects completed all 12 weeks. Three patients withdrew due to adverse events (AEs), with five occurrences of grade 3 AEs. Conclusions Pazopanib with a LFM has acceptable safety and comparable efficacy to fasting administration. Total median pazopanib dose per subject for the study duration was 63.5% of maximum possible conventional dose. A larger study is warranted. Clinical Trial Registration Number: NCT02729194.

Bottom-up proteomics analysis of the secretome of murine islets of Langerhans in elevated glucose levels.

Glucotoxicity is a causative agent of type-2 diabetes, where high glucose levels damage the islets of Langerhans resulting in oxidative damage and endoplasmic reticulum stress. We evaluated the secretomes of healthy CD-1 murine islets. Three experimental conditions were investigated in biological triplicate: a control incubated with 11 mM glucose, 1-day incubation with 25 mM glucose, and 2-day incubation with 25 mM glucose. An SDS-based, filter-aided sample preparation protocol was used to prepare secretomes for analysis. A total of 428 protein groups were identified across the nine samples. Each condition generated between 328-349 protein IDs and intracondition protein overlap was between 66-90% for the biological triplicates. 232 protein groups were identified in all three conditions with 184 quantified at least once in each condition. Significant expression changes were observed for proteins associated with the unfolded protein response, such as proteases, chaperones, and elongation factors, as well as proteins associated with peptide hormone processing and small molecule metabolism.

Sample preparation protocol for bottom-up proteomic analysis of the secretome of the islets of Langerhans.

We evaluate a set of protocols for preparation of the secretome from murine islets of Langerhans for bottom-up proteomic analysis. Of the protocols evaluated, a filter-aided sample preparation based approach using sodium dodecyl sulfate as a detergent to solubilize proteins generated the most protein identifications. A total of 362 protein groups (average of 3.7 peptides/protein) were identified from the secretome using the SDS-FASP protocol; a combination of data from three protocols generated 413 protein group identifications. As expected, the identified proteins included insulin 1 and 2, somatostatin, and glucagon, the four main secreted components from islets. STRING network analysis classified the other proteins as being associated with extracellular exosomes, membrane-bounded vesicles, vesicles, and the extracellular region.

Photoelectron spectra of CeO(-) and Ce(OH)2 (-).

The photoelectron spectrum of CeO(-) exhibits what appears to be a single predominant electronic transition over an energy range in which numerous close-lying electronic states of CeO neutral are well known. The photoelectron spectrum of Ce(OH)2 (-), a molecule in which the Ce atom shares the same formal oxidation state as the Ce atom in CeO(-), also exhibits what appears to be a single transition. From the spectra, the adiabatic electron affinities of CeO and Ce(OH)2 are determined to be 0.936 ± 0.007 eV and 0.69 ± 0.03 eV, respectively. From the electron affinity of CeO, the CeO(-) bond dissociation energy was determined to be 7.7 eV, 0.5 eV lower than the neutral bond dissociation energy. The ground state orbital occupancies of both CeO(-) and Ce(OH)2 (-) are calculated to have 4f 6s(2) Ce(+) superconfigurations, with open-shell states having 4f5d6s superconfiguration predicted to be over 1 eV higher in energy. Low-intensity transitions observed at higher electron binding energies in the spectrum of CeO(-) are tentatively assigned to the (1)Σ(+) (Ω = 0) state of CeO with the Ce+26s2 superconfiguration.

Ce(x)O(y)⁻ (x = 2-3) + D2O reactions: stoichiometric cluster formation from deuteroxide decomposition and anti-Arrhenius behavior.

Reactions between small cerium oxide cluster anions and deuterated water were monitored as a function of both water concentration and temperature in order to determine the temperature dependence of the rate constants. Sequential oxidation reactions of the Ce(x)O(y)⁻ (x = 2, 3) suboxide cluster anions were found to exhibit anti-Arrhenius behavior, with activation energies ranging from 0 to -18 kJ mol⁻¹. Direct oxidation of species up to y = x was observed, after which, -OD abstraction and D2O addition reactions were observed. However, the stoichiometric Ce2O4⁻ and Ce3O6⁻ cluster anions also emerge in reactions between D2O and the respective precursors, Ce2O3D⁻ and Ce3O5D2⁻. Ce2O4⁻ and Ce3O6⁻ product intensities diminish relative to deuteroxide complex intensities with increasing temperature. The kinetics of these reactions are compared to the kinetics of the previously studied Mo(x)O(y)⁻ and W(x)O(y)⁻ reactions with water, and the possible implications for the reaction mechanisms are discussed.

Effects of Fluticasone Propionate on Klebsiella pneumoniae and Gram-Negative Bacteria Associated with Chronic Airway Disease.

Inhaled corticosteroids (ICS) are commonly prescribed first-line treatments for asthma and chronic obstructive pulmonary disease (COPD). Recent evidence has shown that ICS use is associated with changes in the airway microbiome, which may impact clinical outcomes such as potential increased risk for pneumonia in COPD. Although the immunomodulatory effects of corticosteroids are well appreciated, whether ICS could directly influence the behavior of respiratory tract bacteria has been unknown. In this pilot study we explored the effects of fluticasone proprionate, a commonly prescribed inhaled corticosteroid, on respiratory bacteria with an expanded focus on Klebsiella pneumoniae, a species previously implicated in fluticasone-associated pneumonia in COPD. We observed significant effects of fluticasone proprionate on growth responses of K. pneumoniae, as well as other bacterial species isolated from asthmatic patients. Fluticasone-exposed K. pneumoniae displayed altered expression of several bacterial genes and reduced the metabolic activity of bronchial epithelial cells and their expression of human ß-defensin 2. Targeted assays identified a fluticasone metabolite from fluticasone-exposed K. pneumoniae cells, suggesting this species may be capable of metabolizing fluticasone proprionate. Collectively, these observations support the hypothesis that specific members of the airway microbiota possess the functional repertoire to respond to or potentially utilize corticosteroids in their microenvironment. These findings lay a foundation for novel research directions into the potential direct effects of ICS, often prescribed long term to patients, on the broader airway microbial community and on the behavior of specific microbial species implicated in asthma and COPD outcomes. IMPORTANCE Inhaled corticosteroids are widely prescribed for many respiratory diseases, including asthma and COPD. While they benefit many patients, corticosteroids can also have negative effects. Some patients do not improve with treatment and even experience adverse side effects. Recent studies have shown that inhaled corticosteroids can change the make-up of bacteria in the human respiratory tract. However, whether these medications can directly impact the behavior of such bacteria has been unknown. Here, we explored the effects of fluticasone propionate, a commonly prescribed inhaled corticosteroid, on Klebsiella pneumoniae and other airway bacteria of interest, including primary species isolated from adult asthma patients. We provide evidence of growth responses to direct fluticasone exposure in culture and further examined fluticasone's effects on K. pneumoniae, including gene expression changes and effects of fluticasone-exposed bacteria on airway cells. These findings indicate that members of the human airway bacterial community possess the functional ability to respond to corticosteroids, which may have implications for the heterogeneity of treatment response observed clinically.

Resolution and mass range performance in distance-of-flight mass spectrometry with a multichannel focal-plane camera detector.

Distance-of-flight mass spectrometry (DOFMS) is a velocity-based mass-separation technique in which ions are separated in space along the plane of a spatially selective detector. In the present work, a solid-state charge-detection array, the focal-plane camera (FPC), was incorporated into the DOFMS platform. Use of the FPC with our DOFMS instrument resulted in improvements in analytical performance, usability, and versatility over a previous generation instrument that employed a microchannel-plate/phosphor DOF detector. Notably, FPC detection provided resolution improvements of at least a factor of 2, with typical DOF linewidths of 300 µm (R((fwhm)) = 1000). The merits of solid-state detection for DOFMS are evaluated, and methods to extend the DOFMS mass range are considered.

Development of 2,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one inhibitors of aldehyde dehydrogenase 1A (ALDH1A) as potential adjuncts to ovarian cancer chemotherapy.

There is strong evidence that inhibition of one or more Aldehyde Dehydrogenase 1A (ALDH1A) isoforms may be beneficial in chemotherapy-resistant ovarian cancer and other tumor types. While many previous efforts have focused on development of ALDH1A1 selective inhibitors, the most deadly ovarian cancer subtype, high-grade serous (HGSOC), exhibits elevated expression of ALDH1A3. Herein, we report continued development of pan-ALDH1A inhibitors to assess whether broad spectrum ALDH1A inhibition is an effective adjunct to chemotherapy in this critical tumor subtype. Optimization of the CM39 scaffold, aided by metabolite ID and several new ALDH1A1 crystal structures, led to improved biochemical potencies, improved cellular ALDH inhibition in HGSOC cell lines, and substantial improvements in microsomal stability culminating in orally bioavailable compounds. We demonstrate that two compounds 68 and 69 are able to synergize with chemotherapy in a resistant cell line and patient-derived HGSOC tumor spheroids, indicating their suitability for future in vivo proof of concept experiments.

Development of a sensitive LC-MS/MS method for quantification of linezolid and its primary metabolites in human serum.

Linezolid (LZD) is a widely used antimicrobial that is active against a broad range of disease-causing bacteria. Myelosuppression is major treatment-limiting toxicity of LZD that occurs more frequently in patients with renal insufficiency. Quantification of LZD and its two primary metabolites (PNU-142300 and PNU-142586), which undergo significant renal elimination, may support design of improved dosing strategies to mitigate the risk of myelosuppression. In this study, we established the first liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of LZD and its main metabolites in human serum. Proteins in serum samples were precipitated with acetonitrile containing a deuterated internal standard. Chromatographic separation of analytes was performed with Waters X-bridge column (C18, 150 × 4.6 mm, 3.5 µm) at 25 °C and subjected to mass analysis using positive electro-spray ionization. The mobile phase A was water with 0.1% formic acid, and mobile phase B was acetonitrile with 0.1% formic acid at a flow rate of 0.6 mL/min, within a 15 min run time. Standard curves were linear and correlation coefficients (r2) were ≥0.99 for concentration ranges of 0.1-50 µg/mL for LZD and PNU-142300, and 0.1-25 µg/mL for PNU-142586. The inter- and intra-assay precisions were <15% for all analytes in quality control samples, and the accuracies ranged from 97 to 112%. Extraction recoveries ranged from 78 to 103% for all analytes, and there was no significant matrix effect. Samples from 10 patients (5 with renal impairment) were assayed. Mean (SD) LZD, PNU-142300 and PNU-142586 trough concentrations were 19.4(6.8), 11.6(6.8), 25.7(16.4) µg/mL, respectively, in patients with renal impairment. These values were 2.5-, 5.8-, and 6.8-fold higher for LZD, PNU-142300 and PNU-142586, respectively compared to patients without renal impairment. The method was effectively applied in the determination of LZD and its main metabolites in human serum.

Evaluation of a 512-channel Faraday-strip array detector coupled to an inductively coupled plasma Mattauch-Herzog mass spectrograph.

A 512-channel Faraday-strip array detector has been developed and fitted to a Mattauch-Herzog geometry mass spectrograph for the simultaneous acquisition of multiple mass-to-charge values. Several advantages are realized by using simultaneous detection methods, including higher duty cycles, removal of correlated noise, and multianalyte transient analyses independent of spectral skew. The new 512-channel version offers narrower, more closely spaced pixels, providing improved spectral peak sampling and resolution. In addition, the electronics in the amplification stage of the new detector array incorporate a sample-and-hold feature that enables truly simultaneous interrogation of all 512 channels. While sensitivity and linear dynamic range remain impressive for this Faraday-based detector system, limits of detection and isotope ratio data have suffered slightly from leaky p-n junctions produced during the manufacture of the semiconductor-based amplification and readout stages. This paper describes the new 512-channel detector array, the current dominant noise sources, and the figures of merit for the device as pertaining to inductively coupled plasma ionization.

Structure-Based Optimization of a Novel Class of Aldehyde Dehydrogenase 1A (ALDH1A) Subfamily-Selective Inhibitors as Potential Adjuncts to Ovarian Cancer Chemotherapy.

Aldehyde dehydrogenase (ALDH) activity is commonly used as a marker to identify cancer stem-like cells. The three ALDH1A isoforms have all been individually implicated in cancer stem-like cells and in chemoresistance; however, which isoform is preferentially expressed varies between cell lines. We sought to explore the structural determinants of ALDH1A isoform selectivity in a series of small-molecule inhibitors in support of research into the role of ALDH1A in cancer stem cells. An SAR campaign guided by a cocrystal structure of the HTS hit CM39 (7) with ALDH1A1 afforded first-in-class inhibitors of the ALDH1A subfamily with excellent selectivity over the homologous ALDH2 isoform. We also discovered the first reported modestly selective single isoform 1A2 and 1A3 inhibitors. Two compounds, 13g and 13h, depleted the CD133+ putative cancer stem cell pool, synergized with cisplatin, and achieved efficacious concentrations in vivo following IP administration. Compound 13h additionally synergized with cisplatin in a patient-derived ovarian cancer spheroid model.