Ultra high performance liquid chromatography–tandem mass spectrometry method for cyclosporine a quantification in biological samples and lipid nanosystems

Cyclosporine A (CyA) is an immunosuppressant cyclic undecapeptide used for the prevention of organ transplant rejection and in the treatment of several autoimmune disorders. An ultra high performance liquid chromatography–tandem mass spectrometry method (UHPLC–MS/MS) to quantify CyA in lipid nanosystems and mouse biological matrices (whole blood, kidneys, lungs, spleen, liver, heart, brain, stomach and intestine) was developed and fully validated. Chromatographic separation was performed on an Acquity UPLC® BEH C18 column with a gradient elution consisting of methanol and 2 mM ammonium acetate aqueous solution containing 0.1% formic acid at a flow rate of 0.6 mL/min. Amiodarone was used as internal standard (IS). Retention times of IS and CyA were 0.69 min and 1.09 min, respectively. Mass spectrometer operated in electrospray ionization positive mode (ESI+) and multiple reaction monitoring (MRM) transitions were detected, m/z 1220.69 → 1203.7 for CyA and m/z 646 → 58 for IS. The extraction method from biological samples consisted of a simple protein precipitation with 10% trichloroacetic acid aqueous solution and acetonitrile and 5 μL of supernatant were directly injected into the UHPLC–MS/MS system. Linearity was observed between 0.001 μg/mL–2.5 μg/mL (r ≥ 0.99) in all matrices. The precision expressed in coefficient of variation (CV) was below 11.44% and accuracy in bias ranged from −12.78% to 7.99% including methanol and biological matrices. Recovery in all cases was above 70.54% and some matrix effect was observed. CyA was found to be stable in post-extraction whole blood and liver homogenate samples exposed for 6 h at room temperature and 72 h at 4 °C. The present method was successfully applied for quality control of lipid nanocarriers as well as in vivo studies in BALB/c mice

Structural and functional analysis of APOA5 mutations identified in patients with severe hypertriglyceridemia

During the diagnosis of three unrelated patients with severe hypertriglyceridemia, three APOA5 mutations [p.(Ser232_Leu235)del, p.Leu253Pro, and p.Asp332ValfsX4] were found without evidence of concomitant LPL, APOC2, or GPIHBP1 mutations. The molecular mechanisms by which APOA5 mutations result in severe hypertriglyceridemia remain poorly understood, and the functional impairment/s induced by these specific mutations was not obvious. Therefore, we performed a thorough structural and functional analysis that included follow-up of patients and their closest relatives, measurement of apoA-V serum concentrations, and sequencing of the APOA5 gene in 200 nonhyperlipidemic controls. Further, we cloned, overexpressed, and purified both wild-type and mutant apoA-V variants and characterized their capacity to activate LPL. The interactions of recombinant wild-type and mutated apoA-V variants with liposomes of different composition, heparin, LRP1, sortilin, and SorLA/LR11 were also analyzed. Finally, to explore the possible structural consequences of these mutations, we developed a three-dimensional model of full-length, lipid-free human apoA-V. A complex, wide array of impairments was found in each of the three mutants, suggesting that the specific residues affected are critical structural determinants for apoA-V function in lipoprotein metabolism and, therefore, that these APOA5 mutations are a direct cause of hypertriglyceridemia.</p

Complete inhibition of extranodal dissemination of lymphoma by edelfosine-loaded lipid nanoparticles

Lipid nanoparticles (LN) made of synthetic lipids Compritol® 888 ATO and Precirol® ATO 5 were developed, presenting an average size of 110.4 ± 2.1 nm and 103.1 ± 2.9 nm, for Compritol® and Precirol®, respectively, and encapsulation efficiency above 85 % for both type of lipids. These LN decrease the hemolytic toxicity of the drug by 90 %. Pharmacokinetic and biodistribution profiles of the drug were studied after intravenous and oral administration of edelfosine-containing LN, providing an increase in relative oral bioavailability of 1500 % after a single oral administration of drug-loaded LN, maintaining edelfosine plasma levels over 7 days in contrast to a single oral administration of edelfosine solution, which presents a relative oral bioavailability of 10 %. Moreover, edelfosine-loaded LN showed a high accumulation of the drug in lymph nodes and resulted in slower tumor growth than the free drug in a murine lymphoma xenograft model, as well as potent extranodal dissemination inhibition

The Palomar Testbed Interferometer Calibrator Catalog

The Palomar Testbed Interferometer (PTI) archive of observations between 1998 and 2005 is examined for objects appropriate for calibration of optical long-baseline interferometer observations - stars that are predictably point-like and single. Approximately 1,400 nights of data on 1,800 objects were examined for this investigation. We compare those observations to an intensively studied object that is a suitable calibrator, HD217014, and statistically compare each candidate calibrator to that object by computing both a Mahalanobis distance and a Principal Component Analysis. Our hypothesis is that the frequency distribution of visibility data associated with calibrator stars differs from non-calibrator stars such as binary stars. Spectroscopic binaries resolved by PTI, objects known to be unsuitable for calibrator use, are similarly tested to establish detection limits of this approach. From this investigation, we find more than 350 observed stars suitable for use as calibrators (with an additional $\approx 140$ being rejected), corresponding to $\gtrsim 95$ sky coverage for PTI. This approach is noteworthy in that it rigorously establishes calibration sources through a traceable, empirical methodology, leveraging the predictions of spectral energy distribution modeling but also verifying it with the rich body of PTI's on-sky observations.Comment: 100 pages, 7 figures, 7 tables; to appear in the May 2008ApJS, v176n

Electron energy loss and induced photon emission in photonic crystals

The interaction of a fast electron with a photonic crystal is investigated by solving the Maxwell equations exactly for the external field provided by the electron in the presence of the crystal. The energy loss is obtained from the retarding force exerted on the electron by the induced electric field. The features of the energy loss spectra are shown to be related to the photonic band structure of the crystal. Two different regimes are discussed: for small lattice constants $a$ relative to the wavelength of the associated electron excitations $\lambda$, an effective medium theory can be used to describe the material; however, for $a\sim\lambda$ the photonic band structure plays an important role. Special attention is paid to the frequency gap regions in the latter case.Comment: 12 pages, 7 figure

Long‐term safety, efficacy, and quality of life in patients with juvenile idiopathic arthritis treated with intravenous abatacept for up to seven years

ClinicalTrials.gov identifier: NCT00095173[Abstract] Objective. The efficacy and safety of abatacept in patients with juvenile idiopathic arthritis (JIA) who experienced an inadequate response to disease‐modifying antirheumatic drugs were previously established in a phase III study that included a 4‐month open‐label lead‐in period, a 6‐month double‐blind withdrawal period, and a long‐term extension (LTE) phase. The aim of this study was to present the safety, efficacy, and patient‐reported outcomes of abatacept treatment (10 mg/kg every 4 weeks) during the LTE phase, for up to 7 years of followup. Methods. Patients enrolled in the phase III trial could enter the open‐label LTE phase if they had not achieved a response to treatment at month 4 or if they had received abatacept or placebo during the double‐blind period. Results. One hundred fifty‐three (80.5%) of 190 patients entered the LTE phase, and 69 patients (36.3%) completed it. The overall incidence rate (events per 100 patient‐years) of adverse events decreased during the LTE phase (433.61 events during the short‐term phase [combined lead‐in and double‐blind periods] versus 132.39 events during the LTE phase). Similar results were observed for serious adverse events (6.82 versus 5.60), serious infections (1.13 versus 1.72), malignancies (1.12 versus 0), and autoimmune events (2.26 versus 1.18). American College of Rheumatology (ACR) Pediatric 30 (Pedi 30) responses, Pedi 70 responses, and clinically inactive disease status were maintained throughout the LTE phase in patients who continued to receive therapy. Improvements in the Child Health Questionnaire physical and psychosocial summary scores were maintained over time. Conclusion. Long‐term abatacept treatment for up to 7 years was associated with consistent safety, sustained efficacy, and quality‐of‐life benefits in patients with JIA

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Identification of O-mannosylated Virulence Factors in Ustilago maydis

The O-mannosyltransferase Pmt4 has emerged as crucial for fungal virulence in the animal pathogens Candida albicans or Cryptococcus neoformans as well as in the phytopathogenic fungus Ustilago maydis. Pmt4 O-mannosylates specific target proteins at the Endoplasmic Reticulum. Therefore a deficient O-mannosylation of these target proteins must be responsible for the loss of pathogenicity in pmt4 mutants. Taking advantage of the characteristics described for Pmt4 substrates in Saccharomyces cerevisiae, we performed a proteome-wide bioinformatic approach to identify putative Pmt4 targets in the corn smut fungus U. maydis and validated Pmt4-mediated glycosylation of candidate proteins by electrophoretic mobility shift assays. We found that the signalling mucin Msb2, which regulates appressorium differentiation upstream of the pathogenicity-related MAP kinase cascade, is O-mannosylated by Pmt4. The epistatic relationship of pmt4 and msb2 showed that both are likely to act in the same pathway. Furthermore, constitutive activation of the MAP kinase cascade restored appressorium development in pmt4 mutants, suggesting that during the initial phase of infection the failure to O-mannosylate Msb2 is responsible for the virulence defect of pmt4 mutants. On the other hand we demonstrate that during later stages of pathogenic development Pmt4 affects virulence independently of Msb2, probably by modifying secreted effector proteins. Pit1, a protein required for fungal spreading inside the infected leaf, was also identified as a Pmt4 target. Thus, O-mannosylation of different target proteins affects various stages of pathogenic development in U. maydis