Pitiranggon, MashaWu, Hui-ChenJohn, Esther M.Santella, Regina M....
8页
查看更多>>摘要：Efficient and reproducible measurements of multiple polycyclic aromatic hydrocarbon (PAH) metabolites in urinary samples are required to evaluate the complex health effects of PAH exposure. Here, we demonstrate a highly practical, automated off-line solid-phase extraction (SPE) of deconjugated hydroxylated PAHs followed by LC-MS/MS to simultaneously measure eight mono-hydroxylated PAH compounds: 1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 1-hydroxyphenanthrene, 2 & 3-hydroxyphenanthrene, 4-hydroxyphe-nanthrene and 1-hydroxypyrene. Initially, we observed low recovery rates (e.g., 16% for 1-hydroxypyrene) when using previously published methods. We optimized the procedure by choosing polymeric absorbent -based cartridges, automating the sample loading step by diluting samples with 15% methanol/sodium acetate, and most importantly, replacing acetonitrile with methanol as the eluting solvent. Optimized sample preparation has improved the recovery rates to more than 69% for analytes of interest. This improvement led to higher method sensitivity and detection frequency, especially for 1-hydroxypyrene, in all of 100 urine samples collected in the New York City site of the Legacy Girls Study. The limits of detection ranged from 7.6 pg/mL to 20.3 pg/mL using 1 mL of urine, compared to the 2 mL required in CDC, method 09-OD. The average coefficients of variance of quality control samples (n = 60) ranged between 7 and 21%; variance of repeated measurements (n = 45) was less than 10%. This efficient and reliable method for measuring PAH metabolites will greatly benefit epidemi-ology studies and biomonitoring programs.& nbsp;
查看更多>>摘要：Monosaccharides are important players in cell metabolism and potential biomarkers. An effective tool to quantify monosaccharides is required in basic research and healthcare. In this study, we developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay that could simultaneously quantify 14 free monosaccharides and evaluated its performance according to clinical guidance. The LC-MS/MS step separated and quantified 14 monosaccharides with 6 min. The coefficient of variation at the lower limit of quantification was less than 20% for each analyte. The R square values from linear regression analyses were all greater than 0.995. The validated assay was employed to profile free monosaccharides in conditioned media from cell culture and patient sera from glucose tolerance test. Both LO2 cells and HEK293 cells consumed D-glucosamine, D glucose and produced D-glucuronic acid, N-acetyl-D-glucosamine. Additionally, LO2 cells produced D-mannose and L-fucose, whereas HEK293 cells consumed D-mannose. In patient sera from glucose tolerance test, the level of D-glucose increased significantly after glucose intake, but the levels of other monosaccharides didn't. In conclusion, the LC-MS/MS assay we developed for 14-monosaccharide profiling met clinical requirements. The monosaccharide profiling results showed the distinct monosaccharide metabolism between liver and kidney cells, and the ignorable diet effect on 6 serum monosaccharides.
查看更多>>摘要：Measurement of drug concentration in biological matrices (such as serum, plasma, blood, urine, and saliva) is important to determine Bioavailability (BA) and/or Bioequivalence (BE) of a drug product which are required during the drug product development and approval process to support applications for new active substances (INDs, NDAs) and generic (ANDAs) drug products to make critical decisions on safety and efficacy. Because of their vital role, bioanalytical methods should be well-characterized, fully validated and documented to yield reliable results. In present work, a simple, specific, high throughput, accurate and sensitive UHPLC-MS/MS method has been developed and validated for quantification of Minoxidil in human plasma. The analyte and the internal standard were extracted from plasma by Liquid-Liquid Extraction using ethyl acetate. The chromatographic separation was achieved on Thermo Hypersil Gold column (4.6x50mm, 5 mu m) using acetonitrile-0.1% formic acid in water (60:40, v/v) at a flow rate of 0.400 ml/min. Detection by turbospray positive ionization mass spectrometry in the multiple reaction monitoring mode with a mass transition ion-pair of m/z 210.152-* 163.965 (Minoxidil) and m/z 220.267-* 169.089 (Internal Standard-Minoxidil D10) was found to be linear over the concentration range of 1.280 to 151.075 ng/ml. The method was fully validated as per USFDA guidelines and the results were within regulatory limits. The inter and intra-day precision ranged from 5.42 to 9.27% and 2.55-9.42% respectively. The inter and intra-day accuracy ranged from 89.2 to 98.9% and 102-105% respectively. The method was successfully applied to a BE study involving human volunteers.
查看更多>>摘要：Erythrocyte membrane-incorporated phosphatidylethanol (PEth) forms only in the presence of ethanol and, once formed, provides a persisting marker for historical alcohol consumption. Relationships between PEth concentration, extent of consumption and time from consumption are under investigation. Threshold values of PEth have been proposed as indicators for any, or for harmful alcohol consumption. Here, we describe an assay for erythrocyte PEth 16:0/18:1 that offers the efficiency needed for routine clinical deployment, in the context of a fully validated methodology. However, we observe that conventional procedures for validating assay methodology are insufficient where the analyte of interest, membrane-incorporated PEth 16:0/18:1, has different physicochemical properties to the soluble PEth 16:0/18:1 and PEth 16:0/18:1-d5 that are used for making calibrator, controls and internal standards. Whereas the internal standard did fully correct for differences in matrix effects and recovery when different extraction solvents were applied to calibrators and controls (in soluble form), it failed to correct for a 1.5-fold difference in the relative efficiency of two solvents, in this case, acetonitrile and isopropanol in extracting PEth from erythrocyte membrane in clinical samples. Differences in the efficiency of the extraction of membrane-bound PEth translate to different results from the same specimen. That can mean that threshold values derived by one methodology cannot be safely generalised to another. That hampers the generalisability of individual laboratory's experience with PEth assay results. Harmonising extraction methodology between laboratories becomes very important where membrane-incorporated PEth itself remains unavailable as an assay standard.
查看更多>>摘要：Polymyxin B, a last line antibiotic for extensively drug resistant gram-negative bacteria, therapeutic drug monitoring (TDM) is recommended to minimize its nephrotoxicity and improve efficacy. In the present study, we developed a novel quantification method of polymyxin B in dried blood spots (DBS) using liquid chromatography coupled with mass spectrometry (LC-MS/MS), which was performed on a Shimadzu Prominence HPLC system coupled with a 4500 triple quadrupole mass spectrometer. An aliquot of 50 mu L whole blood sample was spotted on Whatman 903 (R) paper cards. Each DBS sample was cut off into a 6 mm diameter disc and extracted by acetonitrile in water (30% in volume, containing 6% formic acid, v/v). Both intra and inter-batch accuracy was in the range of 92.6%-111.0% for polymyxin B1 and 91.5%-111.5% for polymyxin B2. The precision was in the range of 5.2%-12.2% for polymyxin B1 and 4.9%-13.1% for polymyxin B2. The matrix effects for polymyxin B1 and polymyxin B2 at low, medium and high concentrations were ranged from 102.2%-107.9% and 99.8%- 106.2%, respectively. The extraction recoveries were > 85.4%. Stability results showed that DBS cards can be transported at room temperature within 2 days and was stable in sealed plastic bags for 38 days at-70 C. Bland Altman analysis demonstrated that concentrations of polymyxin B measured in DBS and plasma methods were in moderate agreement with 95.1% samples within the 95% confidence interval of limits of agreement. The DBS method was successfully applied in clinic for TDM of polymyxin B, which can be an alternative approach in clinic.
查看更多>>摘要：Gut microbiota is associated with tumor progress and host metabolic disorder, but whether gut microbiota regulation can affect cancer growth through interfering host metabolism maintains unknown yet. Here, we used combined antibiotics (ABX) to build an extremely altered gut microbiota ecosystem and study its influence on the xenograft MC38 tumor as well as the associations of the effects with host metabolisms. The MC38 tumor bearing mouse was treated with ABX (vancomycin, neomycin and imipenem-cilastatin) to build the extremely altered microbiota ecosystem, the gut microbiota diversity alteration was determined by 16S rRNA based gene sequencing. The effects of the altered microbiota on tumor were assessed by cell apoptosis and growth rate of the tumor. The potential metabolic biomarkers and involved metabolism pathways were screened out by UPLC-QTOF-MS/MS based untargeted metabolomics and KEGG analysis respectively. The correlations between key metabolites and microbiota were analyzed by Spearman correlation analysis. Compared with the un-treated mice, the tumor growth of ABX-treated mice was significantly suppressed, and the cell apoptosis was obvi-ously promoted. The gut microbiota diversity was decreased significantly with the dominant bacteria phylum Bacteroidetes and Firmicutes replaced by Proteobacteria, which involved 14 significantly altered bacteria genera. Four potential targeted metabolism pathways, including sphingolipid, glycerophospholipid, arginine-proline and primary bile acid metabolism, were screened out, and the involved key metabolites such as ceramide, phos-phatidylethanolamine, phosphatidylcholine, taurocholic acid and L-proline were correlated significantly with the altered bacteria genera. Through the integrated analysis of microbiome and metabolomics, it was revealed that gut microbiota regulation may inhibit the xenograft MC38 tumor growth potentially by interfering host lipid and amino acid metabolisms, such as sphingolipid, glycerophospholipid, primary bile acid and arginine-proline metabolisms in this case.
Schonn, Mikael AnderssonEskelin, KatriBamford, Dennis H.Poranen, Minna M....
9页
查看更多>>摘要：An efficient chromatography-based virus purification method has been developed and validated for the nonpathogenic infectious virus PRD1. Compared to the conventional method that consists of relatively time-consuming and labour-intensive precipitation and density gradient ultracentrifugation steps, the method developed here is performed in a single flow using tandem-coupled anion exchange and size exclusion chromatography (AIEX-SEC) columns. This inline approach helps to minimize the loss of virus in the process and streamlines time consumption, since no physical transfer of the sample is required between purification steps. In the development process, sample feed composition, dynamic binding capacity and elution conditions for the AIEX resin as well as different exclusion limits for SEC resins were optimized to achieve maximal yield of pure infectious viruses. Utilizing this new approach, a high-quality virus sample was produced from a lysate feed in 320 min with a total yield of 13 mg purified particles per litre of cell lysate, constituting a 3.5-fold yield increase as compared to the conventional method, without compromising the high specific infectivity of the product (6 x 1012 to 7 x 10(12) pfu/mg of protein). The yield of infectious viruses of the lysate feed was 54%. The easy scalability of chromatography-based methods provide a direct route to industrial usage without any significant changes needed to be made to the purification regime. This is especially interesting as the method has high potential to be used for purification of various viruses and nanoparticles, including adenovirus.
查看更多>>摘要：The clustered regularly interspaced short palindromic repeats-CRISPR associated protein9 (CRISPR-Cas9) system, which includes a single guide RNA (sgRNA) and a Cas9 protein, is an emerging and promising gene editing technology that produces specific changes, including insertions, deletions, or substitutions, in desired targets. This approach can be applied in novel therapeutic areas for multiple cancers and genetic diseases, including Parkinson's disease, sickle cell disease, and muscular dystrophy. However, there are many limitations to its potential application to therapeutics. CRISPR-Cas9 activity without side effects, delivery of CRISPR-Cas9 to the target cell within the desired tissue including liver, lungs, brain and muscle and the expression of Cas9 endonuclease in the target cell are key factors in achieving therapeutic efficacy. Generally, single-stranded RNA is immediately degraded in cells and biological fluids such as serum, as chemically unmodified single-stranded RNA shows extremely poor stability against nuclease degradation. To overcome this limitation, sgRNA is chemically modified to obtain a highly stable sgRNA for efficient gene editing in cells and in vivo. Here, we identified the cleavage site of sgRNA for pinpoint modification in biological tissues using mass spectrometry and improved stability of pinpoint modified sgRNA in these fluids. Although improved efficiency provided by modified sgRNA has already been reported, we identified the cleavage site by mass spectrometry and revealed that the stability increased with the pinpoint modification strategy for the first time in this study. In future studies, the efficiency of pinpoint modification strategy for the potential application of sgRNA by systematic routes, including intravenous and subcutaneous administration will be assessed.
NSTL
Elsevier