Defining the mode of action of cisplatin combined with NUC-1031, a phosphoramidate modification of gemcitabine.

The combination of gemcitabine with platinum agents is a widely used chemotherapy regimen for a number of tumour types. Gemcitabine plus cisplatin remains the current therapeutic choice for biliary tract cancer. Gemcitabine is associated with multiple cellular drug resistance mechanisms and other limitations and has thereforelined in use.

DESI-MSI-guided exploration of metabolic-phenotypic relationships reveals a correlation between PI 38:3 and proliferating cells in clear cell renal cell carcinoma via single-section co-registration of multimodal imaging.

A workflow has been evaluated that utilizes a single tissue section to obtain spatially co-registered, molecular, and phenotypical information suitable for AI-enabled image analysis. Desorption electrospray ionization mass spectrometry imaging (DESI-MSI) was used to obtain molecular information followed by conventional histological staining and immunolabelling. The impact of varying DESI-MSI conditions (e.

Snapshots of the Reaction Coordinate of a Thermophilic 2'-Deoxyribonucleoside/ribonucleoside Transferase.

Nucleosides are ubiquitous to life and are required for the synthesis of DNA, RNA, and other molecules crucial for cell survival. Despite the notoriously difficult organic synthesis of nucleosides, 2'-deoxynucleoside analogues can interfere with natural DNA replication and repair and are successfully employed as anticancer, antiviral, and antimicrobial compounds. Nucleoside 2'-deoxyribosyltransferase (dNDT) enzymes catalyze transglycosylation via a covalent 2'-deoxyribosylated enzyme intermediate with retention of configuration, having applications in the biocatalytic synthesis of 2'-deoxynucleoside analogues in a single step.

Human 2'-Deoxynucleoside 5'-Phosphate -Hydrolase 1: Mechanism of 2'-Deoxyuridine 5'-Monophosphate Hydrolysis.

The enzyme 2'-deoxynucleoside 5'-phosphate -hydrolase 1 (DNPH1) catalyzes the -ribosidic bond cleavage of 5-hydroxymethyl-2'-deoxyuridine 5'-monophosphate to generate 2-deoxyribose 5-phosphate and 5-hydroxymethyluracil. DNPH1 accepts other 2'-deoxynucleoside 5'-monophosphates as slow-reacting substrates. DNPH1 inhibition is a promising strategy to overcome resistance to and potentiate anticancer poly(ADP-ribose) polymerase inhibitors.

Catalytic Cycle of the Bifunctional Enzyme Phosphoribosyl-ATP Pyrophosphohydrolase/Phosphoribosyl-AMP Cyclohydrolase.

The bifunctional enzyme phosphoribosyl-ATP pyrophosphohydrolase/phosphoribosyl-AMP cyclohydrolase (HisIE) catalyzes the second and third steps of histidine biosynthesis: pyrophosphohydrolysis of -(5-phospho-β-D-ribosyl)-ATP (PRATP) to -(5-phospho-β-D-ribosyl)-AMP (PRAMP) and pyrophosphate in the C-terminal HisE-like domain, and cyclohydrolysis of PRAMP to -(5'-phospho-D-ribosylformimino)-5-amino-1-(5″-phospho-D-ribosyl)-4-imidazolecarboxamide (ProFAR) in the N-terminal HisI-like domain. Here we use UV-VIS spectroscopy and LC-MS to show putative HisIE produces ProFAR from PRATP. Employing an assay to detect pyrophosphate and another to detect ProFAR, we established the pyrophosphohydrolase reaction rate is higher than the overall reaction rate.

HSD3B1 is an oxysterol 3β-hydroxysteroid dehydrogenase in human placenta.

Most biologically active oxysterols have a 3β-hydroxy-5-ene function in the ring system with an additional site of oxidation at C-7 or on the side-chain. In blood plasma oxysterols with a 7α-hydroxy group are also observed with the alternative 3-oxo-4-ene function in the ring system formed by ubiquitously expressed 3β-hydroxy-Δ-C-steroid oxidoreductase Δ-isomerase, HSD3B7. However, oxysterols without a 7α-hydroxy group are not substrates for HSD3B7 and are not usually observed with the 3-oxo-4-ene function.

The novel anti-cancer fluoropyrimidine NUC-3373 is a potent inhibitor of thymidylate synthase and an effective DNA-damaging agent.

Introduction: Fluoropyrimidines, principally 5-fluorouracil (5-FU), remain a key component of chemotherapy regimens for multiple cancer types, in particular colorectal and other gastrointestinal malignancies. To overcome key limitations and pharmacologic challenges that hinder the clinical utility of 5-FU, NUC-3373, a phosphoramidate transformation of 5-fluorodeoxyuridine, was designed to improve the efficacy and safety profile as well as the administration challenges associated with 5-FU.

Methods: Human colorectal cancer cell lines HCT116 and SW480 were treated with sub-IC doses of NUC-3373 or 5-FU.

Identification of unusual oxysterols biosynthesised in human pregnancy by charge-tagging and liquid chromatography - mass spectrometry.

The aim of this study was to identify oxysterols and any down-stream metabolites in placenta, umbilical cord blood plasma, maternal plasma and amniotic fluid to enhance our knowledge of the involvement of these molecules in pregnancy. We confirm the identification of 20S-hydroxycholesterol in human placenta, previously reported in a single publication, and propose a pathway from 22R-hydroxycholesterol to a C bile acid of probable structure 3β,20R,22R-trihydroxycholest-5-en-(25R)26-oic acid. The pathway is evident not only in placenta, but pathway intermediates are also found in umbilical cord plasma, maternal plasma and amniotic fluid but not non-pregnant women.

Public Health Impacts of Underemployment and Unemployment in the United States: Exploring Perceptions, Gaps and Opportunities.

Background: Unemployment, underemployment, and the quality of work are national occupational health risk factors that drive critical national problems; however, to date, there have been no systematic efforts to document the public health impact of this situation.

Methods: An environmental scan was conducted to explore the root causes and health impacts of underemployment and unemployment and highlight multilevel perspectives and factors in the landscape of underemployment and unemployment.

Methods: included a review of gray literature and research literature, followed by key informant interviews with nine organizational representatives in employment research and policy, workforce development, and industry to assess perceived needs and gaps in practice.

Deep mining of oxysterols and cholestenoic acids in human plasma and cerebrospinal fluid: Quantification using isotope dilution mass spectrometry.

Both plasma and cerebrospinal fluid (CSF) are rich in cholesterol and its metabolites. Here we describe in detail a methodology for the identification and quantification of multiple sterols including oxysterols and sterol-acids found in these fluids. The method is translatable to any laboratory with access to liquid chromatography - tandem mass spectrometry.

Bile acid biosynthesis in Smith-Lemli-Opitz syndrome bypassing cholesterol: Potential importance of pathway intermediates.

Bile acids are the end products of cholesterol metabolism secreted into bile. They are essential for the absorption of lipids and lipid soluble compounds from the intestine. Here we have identified a series of unusual Δ-unsaturated bile acids in plasma and urine of patients with Smith-Lemli-Opitz syndrome (SLOS), a defect in cholesterol biosynthesis resulting in elevated levels of 7-dehydrocholesterol (7-DHC), an immediate precursor of cholesterol.

Metabolism of Non-Enzymatically Derived Oxysterols: Clues from sterol metabolic disorders.

Cholestane-3β,5α,6β-triol (3β,5α,6β-triol) is formed from cholestan-5,6-epoxide (5,6-EC) in a reaction catalysed by cholesterol epoxide hydrolase, following formation of 5,6-EC through free radical oxidation of cholesterol. 7-Oxocholesterol (7-OC) and 7β-hydroxycholesterol (7β-HC) can also be formed by free radical oxidation of cholesterol. Here we investigate how 3β,5α,6β-triol, 7-OC and 7β-HC are metabolised to bile acids.

Identification of unusual oxysterols and bile acids with 7-oxo or 3β,5α,6β-trihydroxy functions in human plasma by charge-tagging mass spectrometry with multistage fragmentation.

7-Oxocholesterol (7-OC), 5,6-epoxycholesterol (5,6-EC), and its hydrolysis product cholestane-3β,5α,6β-triol (3β,5α,6β-triol) are normally minor oxysterols in human samples; however, in disease, their levels may be greatly elevated. This is the case in plasma from patients suffering from some lysosomal storage disorders, e.g.

Charge-tagging liquid chromatography-mass spectrometry methodology targeting oxysterol diastereoisomers.

The introduction of a hydroxy group to the cholesterol skeleton introduces not only the possibility for positional isomers but also diastereoisomers, where two or more isomers have different configurations at one or more of the stereocentres but are not mirror images. The differentiation of diastereoisomers is important as differing isomers can have differing biochemical properties and are formed via different biochemical pathways. Separation of diasterioisomers is not always easy by chromatographic methods Here we demonstrate, by application of charge-tagging and derivatisation with the Girard P reagent, the separation and detection of biologically relevant diastereoisomers using liquid chromatography - mass spectrometry with multistage fragmentation.

Review of systematic reviews on acute procedural pain in children in the hospital setting.

Background: Acute pain is a common experience for hospitalized children. Despite mounting research on treatments for acute procedure-related pain, it remains inadequately treated.

Objective: To critically appraise all systematic reviews on the effectiveness of acute procedure-related pain management in hospitalized children.