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Find video protocols related to scientific articles indexed in Pubmed.
Chemical Vapor Deposition of High Quality Graphene Films from Carbon Dioxide Atmospheres.
ACS Nano
PUBLISHED: 11-15-2014
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The realization of graphene-based, next-generation electronic applications essentially depends on a reproducible, large-scale production of graphene films via chemical vapor deposition (CVD). We demonstrate how key challenges such as uniformity and homogeneity of the copper metal substrate as well as the growth chemistry can be improved by the use of carbon dioxide and carbon dioxide enriched gas atmospheres. Our approach enables graphene film production protocols free of elemental hydrogen and provides graphene layers of superior quality compared to samples produced by conventional hydrogen/methane based CVD processes. The substrates and resulting graphene films were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Raman microscopy, sheet resistance and transport measurements. The superior quality of the as-grown graphene films on copper is indicated by Raman maps revealing average G band widths as low as 18 ± 8 cm(-1) at 514.5 nm excitation. In addition, high charge carrier mobilities of up to 1975 cm(2)/(V s) were observed for electrons in transferred films obtained from a carbon dioxide based growth protocol. The enhanced graphene film quality can be explained by the mild oxidation properties of carbon dioxide, which at high temperatures enables an uniform conditioning of the substrates by an efficient removal of pre-existing and emerging carbon impurities and a continuous suppression and in situ etching of carbon of lesser quality being co-deposited during the CVD growth.
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Carboxymefloquine, the major metabolite of antimalarial drug mefloquine, induces drug metabolizing enzyme and transporter expression by activation of pregnane X receptor.
Antimicrob. Agents Chemother.
PUBLISHED: 10-15-2014
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Malaria patients are frequently co-infected with HIV and mycobacteria causing tuberculosis, which increases the co-administration of drugs and thereby enhances the risk of pharmacokinetic drug-drug interactions. Activation of pregnane X receptor (PXR) by xenobiotics, including many drugs, induces drug metabolism and transport, thereby possibly resulting in attenuation or loss of the therapeutic response of drugs being co-administered. While several artemisinin-type antimalarial drugs have been shown to activate PXR, data on non-artemisinin-type antimalarials are still missing. Therefore this study aims to elucidate the potential of non-artemisinin antimalarial drugs and drug metabolites to activate PXR. The screening of 16 clinically used antimalarial drugs and six major drug metabolites for binding to PXR, using the two-hybrid PXR ligand binding domain assembly assay, identified carboxymefloquine, the major and pharmacological inactive metabolite of the antimalarial drug mefloquine, as a potential PXR ligand. Two-hybrid PXR-coactivator and -corepressor interaction assays, as well as PXR-dependent promoter reporter gene assays, confirmed carboxymefloquine as a novel PXR agonist, which specifically activated the human receptor. In the PXR-expressing intestinal LS174T cells and in primary human hepatocytes, carboxymefloquine induced the expression of drug metabolizing enzymes and transporters on the mRNA and protein level. The crucial role of PXR for carboxymefloquine-dependent induction of gene expression was confirmed by siRNA-mediated knock-down of the receptor. Thus, the clinical use of mefloquine may result in pharmacokinetic drug-drug interactions by means of its metabolite carboxymefloquine. Whether these in vitro finding are of in vivo relevance has to be addressed in future clinical drug-drug interaction studies.
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Acute kidney injury and tools for risk-stratification in 456 patients with hantavirus-induced nephropathia epidemica.
Nephrol. Dial. Transplant.
PUBLISHED: 10-15-2014
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Puumala virus (PUUV) is the most common species of hantavirus in Central Europe. Nephropathia epidemica (NE), caused by PUUV, is characterized by acute kidney injury (AKI) and thrombocytopenia. The major goals of this study were to provide a clear clinical phenotyping of AKI in patients with NE and to develop an easy prediction rule to identify patients, who are at lower risk to develop severe AKI.
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Intranasal delivery of bone marrow derived mesenchymal stem cells, macrophages, and microglia to the brain in mouse models of Alzheimer?s and Parkinson?s disease.
Cell Transplant
PUBLISHED: 10-09-2014
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In view of the rapid preclinical development of cell-based therapies for neurodegenerative disorders, traumatic brain injury, and tumors, the safe and efficient delivery and targeting of therapeutic cells to the central nervous system is critical for maintaining therapeutic efficacy and safety in the respective disease models. Our previous data demonstrated therapeutically efficacious and targeted delivery of mesenchymal stem cells (MSCs) to the brain in the rat 6-hydroxydopamine model of Parkinson?s disease (PD). The present study examined delivery of bone marrow derived MSCs, macrophages, and microglia to the brain in a transgenic model of PD ((Thy1)-h[A30P] ?S) and an APP/PS1 model of Alzheimer?s disease (AD) via intranasal application (INA). INA of microglia in na?ve BL/6 mice led to targeted and effective delivery of cells to the brain. Quantitative PCR analysis of eGFP DNA showed that the brain contained the highest amount of eGFP-microglia (up to 2.1x10(4)) after INA of 1x10(6) cells, while the total amount of cells detected in peripheral organs did not exceed 3.4x10(3). Seven days after INA, MSCs expressing eGFP were detected in the olfactory bulb (OB), cortex, amygdala, striatum, hippocampus, cerebellum, and brainstem of (Thy1)-h[A30P] ?S transgenic mice, showing predominant distribution within the OB and brainstem. INA of eGFP-expressing macrophages in 13 month-old APP/PS1 mice led to delivery of cells to the OB, hippocampus, cortex, and cerebellum. Both, MSCs and macrophages contained Iba-1-positive population of small microglia-like cells and Iba-1-negative large rounded cells showing either intracellular Amyloid beta (macrophages in APP/PS1 model) or ?-Synuclein (MSCs in (Thy1)-h[A30P] ?S model) immunoreactivity. Here we show, for the first time, intranasal delivery of cells to the brain of transgenic PD and AD mouse models. Additional work is needed to determine the optimal dosage (single treatment regimen or repeated administrations) to achieve functional improvement in these mouse models with intranasal microglia/macrophages and MSCs. This manuscript is published as part of the International Association of Neurorestoratology (IANR) special issue of Cell Transplantation.
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Differential expression of drug uptake and efflux transporters in Japanese patients with hepatocellular carcinoma.
Drug Metab. Dispos.
PUBLISHED: 09-17-2014
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Targeted chemotherapy for hepatocellular carcinoma (HCC) is impaired by intrinsic and/or acquired drug resistance. Because drugs used in HCC therapy (e.g., anthracyclines or the tyrosine kinase inhibitor sorafenib) are substrates of uptake and/or efflux transporters, variable expression of these transporters at the plasma membrane of tumor cells may contribute to drug resistance and subsequent clinical response. In this study, the variability of expression of uptake transporters [organic cation transporter (OCT) 1 and OCT3] and efflux transporters [multidrug resistance 1 (MDR1)/P-glycoprotein, multidrug resistance protein (MRP) 1, MRP2, and breast cancer resistance protein (BCRP)], selected for their implication in transporting drugs used in HCC therapy, was investigated. HCC and corresponding nontumor tissue samples were collected from 24 Japanese patients at the time of surgery. Protein expression was determined by immunohistochemistry. Expression data were correlated with clinicopathological characteristics and patients' outcome (median follow-up, 53 months). Generally, expression was highly variable among individual tumor samples. Yet median expression of OCT1, OCT3, and MDR1 in HCC was significantly lower (1.4-, 2.7-, and 2-fold, respectively) than in nontumor tissue, while expression of MRP2 persisted and BCRP showed a trend of increased levels in HCC. Patients with low BCRP expression had significantly shorter overall and recurrence-free survival times. Results suggest different expression patterns of drug transporters in HCC, which are associated only in part with clinicopathological characteristics. Detailed information on expression of drug transporters in HCC may be promising for individualization and optimization of drug therapy for liver cancer.
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Pregnane X receptor activation and silencing promote steatosis of human hepatic cells by distinct lipogenic mechanisms.
Arch. Toxicol.
PUBLISHED: 09-03-2014
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In addition to its well-characterized role in the regulation of drug metabolism and transport by xenobiotics, pregnane X receptor (PXR) critically impacts on lipid homeostasis. In mice, both ligand-dependent activation and knockout of PXR were previously shown to promote hepatic steatosis. To elucidate the respective pathways in human liver, we generated clones of human hepatoma HepG2 cells exhibiting different PXR protein levels, and analyzed effects of PXR activation and knockdown on steatosis and expression of lipogenic genes. Ligand-dependent activation as well as knockdown of PXR resulted in increased steatosis in HepG2 cells. Activation of PXR induced the sterol regulatory element-binding protein (SREBP) 1-dependent lipogenic pathway via PXR-dependent induction of SREBP1a, which was confirmed in primary human hepatocytes. Inhibiting SREBP1 activity by blocking the cleavage-dependent maturation of SREBP1 protein impaired the induction of lipogenic SREBP1 target genes and triglyceride accumulation by PXR activation. On the other hand, PXR knockdown resulted in up-regulation of aldo-keto reductase (AKR) 1B10, which enhanced the acetyl-CoA carboxylase (ACC)-catalyzed reaction step of de novo lipogenesis. In a cohort of human liver samples histologically classified for non-alcoholic fatty liver disease, AKR1B10, SREBP1a and SREBP1 lipogenic target genes proved to be up-regulated in steatohepatitis, while PXR protein was reduced. In summary, our data suggest that activation and knockdown of PXR in human hepatic cells promote de novo lipogenesis and steatosis by induction of the SREBP1 pathway and AKR1B10-mediated increase of ACC activity, respectively, thus providing mechanistic explanations for a putative dual role of PXR in the pathogenesis of steatohepatitis.
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TCF-1-mediated Wnt signaling regulates Paneth cell innate immune defense effectors HD-5 and -6: implications for Crohn's disease.
Am. J. Physiol. Gastrointest. Liver Physiol.
PUBLISHED: 07-03-2014
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Wnt signaling regulates small intestinal stem cell maintenance and Paneth cell differentiation. In patients with ileal Crohn's disease (CD), a decrease of Paneth cell ?-defensins has been observed that is partially caused by impaired TCF-4 and LRP6 function. Here we show reduced expression of the Wnt signaling effector TCF-1 (also known as TCF-7) in patients with ileal CD. Reporter gene assays and in vitro promoter binding analysis revealed that TCF-1 activates ?-defensin HD-5 and HD-6 transcription in cooperation with ?-catenin and that activation is mediated by three distinct TCF binding sites. EMSA analysis showed binding of TCF-1 to the respective motifs. In ileal CD patients, TCF-1 mRNA expression levels were significantly reduced. Moreover, we found specifically reduced expression of active TCF-1 mRNA isoforms. Tcf-1 knockout mice exhibited reduced cryptdin expression in the jejunum, which was not consistently seen at other small intestinal locations. Our data provide evidence that TCF-1-mediated Wnt signaling is disturbed in small intestinal CD, which might contribute to the observed barrier dysfunction in the disease.
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Differential effects of metformin on breast cancer proliferation according to markers of insulin resistance and tumor subtype in a randomized presurgical trial.
Breast Cancer Res. Treat.
PUBLISHED: 06-03-2014
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Treatment of diabetics with metformin is associated with decreased breast cancer risk in observational studies, but it remains unclear if this drug has clinical antineoplastic activity. In a recent presurgical trial, we found a heterogeneous effect of metformin on breast cancer proliferation (ki-67) depending upon insulin resistance (HOMA index). Here, we determined the associations of additional serum biomarkers of insulin resistance, tumor subtype, and drug concentration with ki-67 response to metformin. Two-hundred non-diabetic women were randomly allocated to metformin (850 mg/bid) or placebo for 4 weeks prior to breast cancer surgery. The ki-67 response to metformin was assessed comparing data obtained from baseline biopsy (ki-67 and tumor subtype) and serum markers (HOMA index, C-peptide, IGF-I, IGFBP-1, IGFBP-3, free IGF-I, hs-CRP, adiponectin) with the same measurements at definitive surgery. For patients with a blood sample taken within 24 h from last drug intake, metformin level was measured. Compared with placebo, metformin significantly decreased ki-67 in women with HOMA > 2.8, those in the lowest IGFBP-1 quintile, those in the highest IGFBP-3 quartile, those with low free IGF-I, those in the top hs-CRP tertile, and those with HER2-positive tumors. In women with HOMA index > 2.8, drug levels were positively correlated with the ki-67 decrease, whereas no trend was noted in women with HOMA < 2.8 (p-interaction = 0.07). At conventional antidiabetic doses, the effect of metformin on tumor ki-67 of non-diabetic breast cancer patients varies with host and tumor characteristics. These findings are relevant to design breast cancer prevention and treatment trials with metformin.
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How reliable is the classification of cognitive impairment across different criteria in early and late stages of multiple sclerosis?
J. Neurol. Sci.
PUBLISHED: 04-21-2014
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Prevalence rates of cognitive impairment (CI) in multiple sclerosis (MS) vary between 40% and 80%. Differences in classification criteria for CI may explain this variance.
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Drug-induced acid-base disorders.
Pediatr. Nephrol.
PUBLISHED: 04-19-2014
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The incidence of acid-base disorders (ABDs) is high, especially in hospitalized patients. ABDs are often indicators for severe systemic disorders. In everyday clinical practice, analysis of ABDs must be performed in a standardized manner. Highly sensitive diagnostic tools to distinguish the various ABDs include the anion gap and the serum osmolar gap. Drug-induced ABDs can be classified into five different categories in terms of their pathophysiology: (1) metabolic acidosis caused by acid overload, which may occur through accumulation of acids by endogenous (e.g., lactic acidosis by biguanides, propofol-related syndrome) or exogenous (e.g., glycol-dependant drugs, such as diazepam or salicylates) mechanisms or by decreased renal acid excretion (e.g., distal renal tubular acidosis by amphotericin B, nonsteroidal anti-inflammatory drugs, vitamin D); (2) base loss: proximal renal tubular acidosis by drugs (e.g., ifosfamide, aminoglycosides, carbonic anhydrase inhibitors, antiretrovirals, oxaliplatin or cisplatin) in the context of Fanconi syndrome; (3) alkalosis resulting from acid and/or chloride loss by renal (e.g., diuretics, penicillins, aminoglycosides) or extrarenal (e.g., laxative drugs) mechanisms; (4) exogenous bicarbonate loads: milk-alkali syndrome, overshoot alkalosis after bicarbonate therapy or citrate administration; and (5) respiratory acidosis or alkalosis resulting from drug-induced depression of the respiratory center or neuromuscular impairment (e.g., anesthetics, sedatives) or hyperventilation (e.g., salicylates, epinephrine, nicotine).
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Cohort profile: Greifswald approach to individualized medicine (GANI_MED).
J Transl Med
PUBLISHED: 03-19-2014
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Individualized Medicine aims at providing optimal treatment for an individual patient at a given time based on his specific genetic and molecular characteristics. This requires excellent clinical stratification of patients as well as the availability of genomic data and biomarkers as prerequisites for the development of novel diagnostic tools and therapeutic strategies. The University Medicine Greifswald, Germany, has launched the "Greifswald Approach to Individualized Medicine" (GANI_MED) project to address major challenges of Individualized Medicine. Herein, we describe the implementation of the scientific and clinical infrastructure that allows future translation of findings relevant to Individualized Medicine into clinical practice.
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Impact of point-of-care testing for CYP2C19 on platelet inhibition in patients with acute coronary syndrome and early dual antiplatelet therapy in the emergency setting.
Thromb. Res.
PUBLISHED: 02-26-2014
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Only limited data exist about the role of point of care CYP2C19 testing in the acute setting in the early phase of acute coronary syndromes (ACS). Therefore, the present study was designed to investigate the impact of CYP2C19 loss-of-function point-of-care (POC) genotyping in patients presenting with acute coronary syndromes (ACS) and treated with dual antiplatelet therapy in the emergency setting.
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Genetic biomarkers in epilepsy.
Neurotherapeutics
PUBLISHED: 02-26-2014
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The identification of valid biomarkers for outcome prediction of diseases and improvement of drug response, as well as avoidance of side effects is an emerging field of interest in medicine. The concept of individualized therapy is becoming increasingly important in the treatment of patients with epilepsy, as predictive markers for disease prognosis and treatment outcome are still limited. Currently, the clinical decision process for selection of an antiepileptic drug (AED) is predominately based on the patient's epileptic syndrome and side effect profiles of the AEDs, but not on effectiveness data. Although standard dosages of AEDs are used, supplemented, in part, by therapeutic monitoring, the response of an individual patient to a specific AED is generally unpredictable, and the standard care of patients in antiepileptic treatment is more or less based on trial and error. Therefore, there is an urgent need for valid predictive biomarkers to guide patient-tailored individualized treatment strategies in epilepsy, a research area that is still in its infancy. This review focuses on genomic factors as part of an individual concept for AED therapy summarizing examples that influence the prognosis of the disease and the response to AEDs, including side effects.
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Mechanisms and assessment of statin-related muscular adverse effects.
Br J Clin Pharmacol
PUBLISHED: 02-14-2014
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Statin-associated muscular adverse effects cover a wide range of symptoms, including asymptomatic increase of creatine kinase serum activity and life-threatening rhabdomyolysis. Different underlying pathomechanisms have been proposed. However, a unifying concept of the pathogenesis of statin-related muscular adverse effects has not emerged so far. In this review, we attempt to categorize these mechanisms along three levels. Firstly, among pharmacokinetic factors, it has been shown for some statins that inhibition of cytochrome P450-mediated hepatic biotransformation and hepatic uptake by transporter proteins contribute to an increase of systemic statin concentrations. Secondly, at the myocyte membrane level, cell membrane uptake transporters affect intracellular statin concentrations. Thirdly, at the intracellular level, inhibition of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase results in decreased intracellular concentrations of downstream metabolites (e.g. selenoproteins, ubiquinone, cholesterol) and alteration of gene expression (e.g. ryanodine receptor 3, glycine amidinotransferase). We also review current recommendations for prescribers.
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Detection of rearrangements and transcriptional up-regulation of ALK in FFPE lung cancer specimens using a novel, sensitive, quantitative reverse transcription polymerase chain reaction assay.
J Thorac Oncol
PUBLISHED: 02-06-2014
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The approved dual-color fluorescence in situ hybridization (FISH) test for the detection of anaplastic lymphoma receptor tyrosine kinase (ALK) gene rearrangements in non-small-cell lung cancer (NSCLC) is complex and represents a low-throughput assay difficult to use in daily diagnostic practice. We devised a sensitive and robust routine diagnostic test for the detection of rearrangements and transcriptional up-regulation of ALK.
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Interplay between endothelin and erythropoietin in astroglia: the role in protection against hypoxia.
Int J Mol Sci
PUBLISHED: 01-27-2014
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We show that, under in vitro conditions, the vulnerability of astroglia to hypoxia is reflected by alterations in endothelin (ET)-1 release and capacity of erythropoietin (EPO) to regulate ET-1 levels. Exposure of cells to 24 h hypoxia did not induce changes in ET-1 release, while 48-72 h hypoxia resulted in increase of ET-1 release from astrocytes that could be abolished by EPO. The endothelin receptor type A (ETA) antagonist BQ123 increased extracellular levels of ET-1 in human fetal astroglial cell line (SV-FHAS). The survival and proliferation of rat primary astrocytes, neural precursors, and neurons upon hypoxic conditions were increased upon administration of BQ123. Hypoxic injury and aging affected the interaction between the EPO and ET systems. Under hypoxia EPO decreased ET-1 release from astrocytes, while ETA receptor blockade enhanced the expression of EPO mRNA and EPO receptor in culture-aged rat astroglia. The blockade of ETA receptor can increase the availability of ET-1 to the ETB receptor and can potentiate the neuroprotective effects of EPO. Thus, the new therapeutic use of combined administration of EPO and ETA receptor antagonists during hypoxia-associated neurodegenerative disorders of the central nervous system (CNS) can be suggested.
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Incorporation of pharmacogenomics into routine clinical practice: the Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline development process.
Curr. Drug Metab.
PUBLISHED: 01-21-2014
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The Clinical Pharmacogenetics Implementation Consortium (CPIC) publishes genotype-based drug guidelines to help clinicians understand how available genetic test results could be used to optimize drug therapy. CPIC has focused initially on well-known examples of pharmacogenomic associations that have been implemented in selected clinical settings, publishing nine to date. Each CPIC guideline adheres to a standardized format and includes a standard system for grading levels of evidence linking genotypes to phenotypes and assigning a level of strength to each prescribing recommendation. CPIC guidelines contain the necessary information to help clinicians translate patient-specific diplotypes for each gene into clinical phenotypes or drug dosing groups. This paper reviews the development process of the CPIC guidelines and compares this process to the Institute of Medicine's Standards for Developing Trustworthy Clinical Practice Guidelines.
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LC-MS/MS method for the simultaneous quantification of artesunate and its metabolites dihydroartemisinin and dihydroartemisinin glucuronide in human plasma.
Anal Bioanal Chem
PUBLISHED: 01-20-2014
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Artesunate (AS), a hemisuccinate derivative of artemisinin, is readily soluble in water and can easily be used in formulations for parenteral treatment of severe malaria. AS is rapidly hydrolyzed to the active metabolite dihydroartemisinin (DHA) and primarily eliminated by biliary excretion after glucuronidation. To investigate systematically the AS metabolism and pharmacokinetics, a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of AS and its metabolites DHA and DHA glucuronide (DHAG) in human plasma samples was developed. Compared to previous methods, our method includes for the first time the quantification of the glucuronide metabolite using a newly synthesized stable isotope-labeled analogue as internal standard. Sample preparation was performed with only 50 ?L plasma by high-throughput solid-phase extraction in the 96-well plate format. Separation of the analytes was achieved on a Poroshell 120 EC-C18 column (50*2.1 mm, 2.7 ?m, Agilent Technologies, Waldbronn, Germany). The method was validated according to FDA guidelines. Calibration curves were linear over the entire range from 1 to 2,500 nM (0.4-961.1 ng/mL), 165 to 16,500 nM (46.9-4,691.8 ng/mL), and 4 to 10,000 nM (1.8-4,604.7 ng/mL) for AS, DHA, and DHAG, respectively. Intra- and interbatch accuracy, determined as a deviation between nominal and measured values, ranged from -5.7 to 3.5% and from 2.7 to 5.8%, respectively. The assay variability ranged from 1.5 to 10.9% for intra- and interbatch approaches. All analytes showed extraction recoveries above 85%. The method was successfully applied to plasma samples from patients under AS treatment.
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Solute carrier transporter and drug-related nephrotoxicity: the impact of proximal tubule cell models for preclinical research.
Expert Opin Drug Metab Toxicol
PUBLISHED: 01-08-2014
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The final excretion step of several drugs is facilitated by membrane transporters of the Solute carrier (SLC) family expressed in the proximal tubules of the kidney. Membrane transporters contribute substantially to the pharmacokinetic profile of drugs and play important roles in drug-induced nephrotoxicity. Different cell models have been applied as tools for the assessment of nephrotoxic effects caused by drugs.
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Concomitant use of tamoxifen and endoxifen in postmenopausal early breast cancer: prediction of plasma levels by physiologically-based pharmacokinetic modeling.
Springerplus
PUBLISHED: 01-01-2014
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To overcome cytochrome P450 2D6 (CYP2D6) mediated tamoxifen resistance in postmenopausal early breast cancer, CYP2D6 phenotype-adjusted tamoxifen dosing in patients with impaired CYP2D6 metabolism and/or the application of endoxifen, the most potent tamoxifen metabolite, are alternative treatment options. To elucidate both strategies comprehensively we used a physiologically-based pharmacokinetic (PBPK) modeling approach.
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Cellular uptake of imatinib into leukemic cells is independent of human organic cation transporter 1 (OCT1).
Clin. Cancer Res.
PUBLISHED: 12-18-2013
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In addition to mutated BCR-ABL1 kinase, the organic cation transporter 1 (OCT1, encoded by SLC22A1) has been considered to contribute to imatinib resistance in patients with chronic myeloid leukemia (CML). Since data are conflicting as to whether OCT1 transports imatinib and may serve as clinical biomarker we used a combination of different approaches including animal experiments to elucidate comprehensively the impact of OCT1 on cellular imatinib uptake.
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Does the Clinical Phenotype of Fatal Familial Insomnia Depend on PRNP codon 129 Methionine-Valine Polymorphism?
J Clin Sleep Med
PUBLISHED: 12-17-2013
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Fatal familial insomnia (FFI) is a rare, hereditary prion-protein disease. Methionine-valine polymorphism at codon 129 of the prion-protein gene (PRNP) determines the phenotype in other hereditary prion-protein diseases, but association with the clinical phenotype in FFI remains uncertain. Early clinical findings in FFI comprise disturbances of the sleep-wake cycle and mild neuropsychiatric changes which typically emerge during middle to late adulthood. Here we describe an unusually early onset and rapid progression of FFI associated with dorsal midbrain involvement in a female patient with PRNP mutation at codon 178 and homozygote methionine polymorphism at codon 129. Early dorsal midbrain involvement became apparent by total loss of REM sleep and isolated bilateral trochlear nerve palsy. Early onset and rapid progression disease type associated with dorsal midbrain involvement may indicate a different spatiotemporal distribution of the neurodegenerative process in FFI patients with PRNP mutation and codon 129 methionine homozygosity compared to methioninevaline heterozygosity.
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Expression of stromal cell-derived factor-1 receptors CXCR4 and CXCR7 on circulating platelets of patients with acute coronary syndrome and association with left ventricular functional recovery.
Eur. Heart J.
PUBLISHED: 10-29-2013
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Surface expression of stromal cell-derived factor-1 (SDF-1) on platelets is enhanced during ischaemic events and might play an important role in peripheral homing and myocardial repair. As SDF-1 effects are mediated through CXCR4/CXCR7, we investigated platelet expression of SDF-1/CXCR4/CXCR7 in patients with coronary artery disease (CAD).
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Simultaneous quantification of mefloquine (+)- and (-)-enantiomers and the carboxy metabolite in dried blood spots by liquid chromatography/tandem mass spectrometry.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 09-16-2013
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Mefloquine (MQ), a racemic mixture of (+)-(11S,12R)- and (-)-(11R,12S)-MQ, has been used for treatment and prophylaxis of malaria for almost 30 years. MQ is metabolized by the cytochrome P450 3A subfamily to 4-carboxymefloquine (CMQ), which shows no antimalarial activity in vitro. Highly stereospecific pharmacokinetics of MQ have been reported, although with contradictory results. This might be due to incorrect assignment of the absolute configuration as shown only recently. Gastrointestinal as well as neuropsychiatric adverse events were described after prophylaxis and treatment with MQ. Data are indicating that the tolerability of the enantiomers may vary considerably. An involvement of the main metabolite CMQ in the development of neuropsychiatric adverse events has also been supposed. Due to these inconsistent results we established a novel liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of MQ enantiomers and the metabolite CMQ to investigate the attribution of efficacy and adverse effects to the single enantiomers as well as the main metabolite. Separation of the MQ enantiomers was achieved on a quinidine-based zwitterionic chiral stationary phase column, CHIRALPAK(®) ZWIX(-) (3.0×150mm, 3?m) in an isocratic run using a pre-mixed eluent consisting of methanol/acetonitrile/water (49:49:2 v/v) with 25mM formic acid and 12.5mM ammonium formate. We used stable isotope-labelled analogues as internal standards. The method was validated according to the FDA guidelines. With a linear calibration range from 5 to 2000nM for the MQ enantiomers and from 13 to 2600nM for CMQ respectively, the method was successfully applied to dried blood spot (DBS) samples from patients under prophylactic MQ treatment. The method was also applicable for plasma samples.
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ABCC11/MRP8 polymorphisms affect 5-fluorouracil-induced severe toxicity and hepatic expression.
Pharmacogenomics
PUBLISHED: 09-13-2013
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Because 5-fluorodeoxyuridine monophosphate (5-FdUMP), an anabolic active metabolite of 5-fluorouracil (5-FU), is a substrate of MRP8 (encoded by ABCC11), we investigated whether ABCC11 polymorphisms play a role in severe toxicity of 5-FU.
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The letrozole phase 1 metabolite carbinol as a novel probe drug for UGT2B7.
Drug Metab. Dispos.
PUBLISHED: 08-21-2013
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Carbinol [4,4-(hydroxymethylene)dibenzonitrile] is the main phase 1 metabolite of letrozole, a nonsteroidal aromatase inhibitor used for endocrine therapy in postmenopausal breast cancer. We elucidated the contribution of UDP-glucuronosyltransferase (UGT) isoforms on the glucuronidation of carbinol. Identification of UGT isoforms was performed using a panel of recombinant human UGT enzymes. Kinetic studies were done in recombinant human UGT2B7 and pooled human liver microsomes (HLMs). A liquid chromatography-tandem mass spectrometry method was used for detection of metabolites. To assess the impact of UGT2B7*2, we determined the carbinol glucuronidation activity using HLM as well as UGT2B7 protein expression in 148 human livers. Moreover, we analyzed the plasma concentrations of 60 letrozole-treated breast cancer patients. We identified UGT2B7 as the predominant UGT isoform involved in carbinol glucuronidation. In HLMs and recombinant UGT2B7, we determined K(m) values (9.99 and 9.56 µM) and V(max) values (3430 and 2399 pmol/min per milligram of protein), respectively. In the set of 148 human livers, carbinol glucuronidation activity significantly correlated with UGT2B7 protein as determined by Western blotting (r(s) = 0.5088, P < 0.0001). Neither carbinol glucuronidation activity (*1/*1: n = 25, 2434 ± 1018; *1/*2: n = 80, 2356 ± 1372; *2/*2: n = 43, 2251 ± 1421 pmol/min per milligram of protein) nor UGT2B7 protein expression was altered by the UGT2B7*2 genotype. No impact of UGT2B7*2 on plasma levels of carbinol and carbinol-gluc [bis(4-cyanophenyl)methyl hexopyranosiduronic acid] in 60 letrozole-treated patients was found. Taken together, these findings suggest carbinol as a novel in vitro probe substrate for UGT2B7. In vitro and in vivo data suggest a lack of influence of the UGT2B7*2 polymorphism on carbinol glucuronidation.
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DNA methylation of the SLC16A3 promoter regulates expression of the human lactate transporter MCT4 in renal cancer with consequences for clinical outcome.
Clin. Cancer Res.
PUBLISHED: 07-23-2013
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The monocarboxylate transporter 4 (MCT4) is a metabolic target in tumor biology because it mediates lactate transport across membranes resulting in antiapoptotic effects. Cell experiments support the importance of MCT4 in clear cell renal cell carcinoma (ccRCC). In this study, we assessed the prognostic potential of MCT4 expression in ccRCC and its epigenetic regulation by DNA methylation as novel predictive marker for patient outcome using independent ccRCC cohorts.
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Intestinal absorption, metabolism, and excretion of (-)-epicatechin in healthy humans assessed by using an intestinal perfusion technique.
Am. J. Clin. Nutr.
PUBLISHED: 07-17-2013
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(-)-Epicatechin is a dietary flavonoid present in many foods that affects vascular function, but its action is limited by incomplete absorption, conjugation, and metabolism. Factors that influence this activity may be attributed to instability in the gastrointestinal lumen, low permeability across the intestinal wall, or active efflux from enterocytes and extensive conjugation.
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Impact of Vitamin D Receptor VDR rs2228570 Polymorphism in Oldest Old.
Kidney Blood Press. Res.
PUBLISHED: 07-11-2013
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Background: Calcitriol, a key player in the regulation of mineral metabolism, influences, directly or by increasing plasma Ca(2+) and phosphate levels, a multitude of physiological functions, such as bone mineralization, cell proliferation, immune response, carbohydrate metabolism, blood pressure, platelet reactivity, gastric acid secretion, cognitive function and mood. Calcitriol is mainly effective by stimulation of the Vitamin D receptor VDR. The responsiveness of VDR may be affected by gene variants, such as the FokI polymorphism (rs2228570). The GG gene variant is expected to be more active than the GA or AA gene variant. The present study explored the impact of VDR rs2228570 on survival and health of oldest old individuals (> 90 years). Methods: 101 individuals > 90 years were examined and genotyped. As a result, the prevalence of GG, GA & AA was 36 (10 ?, 26?), 52 (24 ?, 28?) and 13 (4 ?, 9?), respectively, a prevalence not significantly different from the frequency in public available dbSNP and a population (n = 208) of young volunteers (average age 49 years). Results: As compared to carriers of GG, carriers of AA and/or GA displayed significantly (p<0.05) lower diastolic blood pressure (significant only in ?), higher instrumental activity of daily life (IADL) score and more frequent hospital visits (significant only in ?), significantly lower prevalence of depression (significant in ?+?), renal disease (significant only in ?), allergy, peptic ulcer and urolithiasis (significant only in ?), as well as significantly higher prevalence of transitoric ischemic attacks. In a younger population a German version of the NEO-FFI, allowing reliable and valid assessment of personality, revealed decreased neuroticism (significant only in ?) and increased extraversion in AA carriers. Conclusion: The Vitamin D receptor gene variant VDR rs2228570 has only little impact on life span but may affect a variety of pathophysiologically relevant functions including mood. © 2013 S. Karger AG, Basel.
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Metformin improves healthspan and lifespan in mice.
Nat Commun
PUBLISHED: 06-26-2013
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Metformin is a drug commonly prescribed to treat patients with type 2 diabetes. Here we show that long-term treatment with metformin (0.1% w/w in diet) starting at middle age extends healthspan and lifespan in male mice, while a higher dose (1% w/w) was toxic. Treatment with metformin mimics some of the benefits of calorie restriction, such as improved physical performance, increased insulin sensitivity, and reduced low-density lipoprotein and cholesterol levels without a decrease in caloric intake. At a molecular level, metformin increases AMP-activated protein kinase activity and increases antioxidant protection, resulting in reductions in both oxidative damage accumulation and chronic inflammation. Our results indicate that these actions may contribute to the beneficial effects of metformin on healthspan and lifespan. These findings are in agreement with current epidemiological data and raise the possibility of metformin-based interventions to promote healthy aging.
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Clinical markers of early nigrostriatal neurodegeneration in idiopathic rapid eye movement sleep behavior disorder.
Sleep Med.
PUBLISHED: 06-10-2013
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Rapid eye movement sleep behavior disorder (RBD) is an early feature in ? synucleinopathies and may precede other clinical manifestations of disease for several years. Olfactory dysfunction and mild motor abnormalities (MMAs) are highly prevalent in prodromal ? synucleinopathies such as RBD and are suspected to be predictive neurodegenerative markers. Because both markers also are highly prevalent in the healthy elderly population, the discriminative value to detect an early neurodegenerative process is unclear.
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Structural polymorphism in self-assembled networks of a triphenylene based macrocycle.
Phys Chem Chem Phys
PUBLISHED: 05-18-2013
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Understanding and controlling the structural polymorphism in self-assembled networks of functional molecules merit special attention. In this contribution, we describe the concentration controlled structural evolution in self-assembled monolayers of a large triangular discotic macrocycle at the liquid-solid interface. Scanning tunneling microscopy (STM) reveals that the adlayers formed by an alkoxy substituted cyclo-tris(7,9-triphenylenylene) macrocycle exhibit concentration dependent 2D phase behavior at the 1,2,4-trichlorobenzene/HOPG interface. The self-assembled network evolves from high-density linear packing which is formed at relatively high concentrations to a low-density porous pattern at lower concentrations. A trimeric hexagonal phase exists at intermediate concentrations examined. The transformation of the trimeric hexagonal phase to the linear phase could be monitored by recording time-dependent STM images. The self-assembly behavior is affected significantly by the choice of the organic solvent where an amorphous network is formed along with high-density linear packing at the 1-phenyloctane/HOPG interface. The results presented here provide detailed insight into the polymorphism phenomenon exhibited by an organic semiconductor and furnish general guidelines to control the morphology of thin films of such technologically important materials.
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Metformin decreases glucose oxidation and increases the dependency of prostate cancer cells on reductive glutamine metabolism.
Cancer Res.
PUBLISHED: 05-17-2013
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Metformin inhibits cancer cell proliferation, and epidemiology studies suggest an association with increased survival in patients with cancer taking metformin; however, the mechanism by which metformin improves cancer outcomes remains controversial. To explore how metformin might directly affect cancer cells, we analyzed how metformin altered the metabolism of prostate cancer cells and tumors. We found that metformin decreased glucose oxidation and increased dependency on reductive glutamine metabolism in both cancer cell lines and in a mouse model of prostate cancer. Inhibition of glutamine anaplerosis in the presence of metformin further attenuated proliferation, whereas increasing glutamine metabolism rescued the proliferative defect induced by metformin. These data suggest that interfering with glutamine may synergize with metformin to improve outcomes in patients with prostate cancer.
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Impact of metabolizing enzymes on drug response of endocrine therapy in breast cancer.
Expert Rev. Mol. Diagn.
PUBLISHED: 05-04-2013
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Estrogen-receptor positive breast cancer accounts for 75% of diagnosed breast cancers worldwide. There are currently two major options for adjuvant treatment: tamoxifen and aromatase inhibitors. Variability in metabolizing enzymes determines their pharmacokinetic profile, possibly affecting treatment response. Therefore, prediction of therapy outcome based on genotypes would enable a more personalized medicine approach, providing optimal therapy for each patient. In this review, the authors will discuss the current evidence on the most important metabolizing enzymes in endocrine therapy, with a special focus on CYP2D6 and its role in tamoxifen metabolism.
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Intraperitoneal Chemotherapy of Peritoneal Carcinomatosis Using Pressurized Aerosol as an Alternative to Liquid Solution: First Evidence for Efficacy.
Ann. Surg. Oncol.
PUBLISHED: 04-23-2013
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Peritoneal carcinomatosis (PC) is an unmet medical need. Despite recent improvements, systemic chemotherapy has limited efficacy. We report the first application of intraperitoneal chemotherapy as a pressurized aerosol in human patients.
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Postoperative survival of lung cancer patients: are there predictors beyond TNM?
Anticancer Res.
PUBLISHED: 04-09-2013
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We report on survival data of 595 patients with stage I-III lung cancer with respect to TNM classification.
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Personalized cardiovascular medicine: concepts and methodological considerations.
Nat Rev Cardiol
PUBLISHED: 03-26-2013
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The primary goals of personalized medicine are to optimize diagnostic and treatment strategies by tailoring them to the specific characteristics of an individual patient. In this Review, we summarize basic concepts and methods of personalizing cardiovascular medicine. In-depth characterization of study participants and patients in general practice using standardized methods is a pivotal component of study design in personalized medicine. Standardization and quality assurance of clinical data are similarly important, but in daily practice imprecise definitions of clinical variables can reduce power and introduce bias, which limits the validity of the data obtained as well as their potential clinical applicability. Changes in statistical methods with personalized medicine include a shift from dichotomous outcomes towards continuously measured variables, predictive modelling, and individualized medical decisions, subgroup analyses, and data-mining strategies. A variety of approaches to personalized medicine exist in cardiovascular research and clinical practice that might have the potential to individualize diagnostic and therapeutic procedures. For some of the emerging methods, such as data mining, the most-efficient way to use these tools is not yet fully understood. In addition, the predictive models-although promising-are far from mature, and are likely to be greatly improved by using available large-scale data sets.
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Quantifying the effect of covariates on concentrations and effects of steady-state phenprocoumon using a population pharmacokinetic/pharmacodynamic model.
Clin Pharmacokinet
PUBLISHED: 03-23-2013
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The oral anticoagulant phenprocoumon, similar to other vitamin K antagonists, is characterized by pronounced interindividual variability in the doses needed to achieve the desired therapeutic effect. Previous studies assessed the effect of genetic and demographic covariates on empirical dose requirements of phenprocoumon to enable individualized dose prediction. The aim of the present study was to quantify major sources of interindividual variability separately on the pharmacokinetics and pharmacodynamics of phenprocoumon using a population pharmacokinetic-pharmacodynamic model.
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Circulating lysophosphatidylcholines are markers of a metabolically benign nonalcoholic fatty liver.
Diabetes Care
PUBLISHED: 03-20-2013
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Nonalcoholic fatty liver (NAFL) is thought to contribute to insulin resistance and its metabolic complications. However, some individuals with NAFL remain insulin sensitive. Mechanisms involved in the susceptibility to develop insulin resistance in humans with NAFL are largely unknown. We investigated circulating markers and mechanisms of a metabolically benign and malignant NAFL by applying a metabolomic approach.
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Nomenclature for alleles of the thiopurine methyltransferase gene.
Pharmacogenet. Genomics
PUBLISHED: 02-15-2013
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The drug-metabolizing enzyme thiopurine methyltransferase (TPMT) has become one of the best examples of pharmacogenomics to be translated into routine clinical practice. TPMT metabolizes the thiopurines 6-mercaptopurine, 6-thioguanine, and azathioprine, drugs that are widely used for treatment of acute leukemias, inflammatory bowel diseases, and other disorders of immune regulation. Since the discovery of genetic polymorphisms in the TPMT gene, many sequence variants that cause a decreased enzyme activity have been identified and characterized. Increasingly, to optimize dose, pretreatment determination of TPMT status before commencing thiopurine therapy is now routine in many countries. Novel TPMT sequence variants are currently numbered sequentially using PubMed as a source of information; however, this has caused some problems as exemplified by two instances in which authors articles appeared on PubMed at the same time, resulting in the same allele numbers given to different polymorphisms. Hence, there is an urgent need to establish an order and consensus to the numbering of known and novel TPMT sequence variants. To address this problem, a TPMT nomenclature committee was formed in 2010, to define the nomenclature and numbering of novel variants for the TPMT gene. A website (http://www.imh.liu.se/tpmtalleles) serves as a platform for this work. Researchers are encouraged to submit novel TPMT alleles to the committee for designation and reservation of unique allele numbers. The committee has decided to renumber two alleles: nucleotide position 106 (G>A) from TPMT*24 to TPMT*30 and position 611 (T>C, rs79901429) from TPMT*28 to TPMT*31. Nomenclature for all other known alleles remains unchanged.
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Modified Foxp3 mRNA protects against asthma through an IL-10-dependent mechanism.
J. Clin. Invest.
PUBLISHED: 02-08-2013
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Chemically modified mRNA is capable of inducing therapeutic levels of protein expression while circumventing the threat of genomic integration often associated with viral vectors. We utilized this novel therapeutic tool to express the regulatory T cell transcription factor, FOXP3, in a time- and site-specific fashion in murine lung, in order to prevent allergic asthma in vivo. We show that modified Foxp3 mRNA rebalanced pulmonary T helper cell responses and protected from allergen-induced tissue inflammation, airway hyperresponsiveness, and goblet cell metaplasia in 2 asthma models. This protection was conferred following delivery of modified mRNA either before or after the onset of allergen challenge, demonstrating its potential as both a preventive and a therapeutic agent. Mechanistically, FOXP3 induction controlled Th2 and Th17 inflammation by regulating innate immune cell recruitment through an IL-10-dependent pathway. The protective effects of FOXP3 could be reversed by depletion of IL-10 or administration of recombinant IL-17A or IL-23. Delivery of Foxp3 mRNA to sites of inflammation may offer a novel, safe therapeutic tool for the treatment of allergic asthma and other diseases driven by an imbalance in helper T cell responses.
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Mucosal improvement in patients with moderate to severe postoperative endoscopic recurrence of Crohns disease and azathioprine metabolite levels.
Inflamm. Bowel Dis.
PUBLISHED: 02-08-2013
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The value of azathioprine metabolites (6-thioguanine nucleotides [6-TGN]) in monitoring clinical treatment response is still controversially discussed. Data regarding thiopurine metabolite levels and endoscopic improvement are lacking.
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Functional genomics suggest neurogenesis in the adult human olfactory bulb.
Brain Struct Funct
PUBLISHED: 02-04-2013
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The human olfactory bulb displays high morphologic dynamics changing its volume with olfactory function, which has been explained by active neurogenetic processes. Discussion continues whether the human olfactory bulb hosts a continuous turnover of neurons. We analyzed the transcriptome via RNA quantification of adult human olfactory bulbs and intersected the set of expressed transcriptomic genes with independently available proteomic expression data. To obtain a functional genomic perspective, this intersection was analyzed for higher-level organization of gene products into biological pathways established in the gene ontology database. We report that a fifth of genes expressed in adult human olfactory bulbs serve functions of nervous system or neuron development, half of them functionally converging to axonogenesis but no other non-neurogenetic biological processes. Other genes were expectedly involved in signal transmission and response to chemical stimuli. This provides a novel, functional genomics perspective supporting the existence of neurogenesis in the adult human olfactory bulb.
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Cytochrome P450 enzymes in drug metabolism: regulation of gene expression, enzyme activities, and impact of genetic variation.
Pharmacol. Ther.
PUBLISHED: 01-16-2013
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Cytochromes P450 (CYP) are a major source of variability in drug pharmacokinetics and response. Of 57 putatively functional human CYPs only about a dozen enzymes, belonging to the CYP1, 2, and 3 families, are responsible for the biotransformation of most foreign substances including 70-80% of all drugs in clinical use. The highest expressed forms in liver are CYPs 3A4, 2C9, 2C8, 2E1, and 1A2, while 2A6, 2D6, 2B6, 2C19 and 3A5 are less abundant and CYPs 2J2, 1A1, and 1B1 are mainly expressed extrahepatically. Expression of each CYP is influenced by a unique combination of mechanisms and factors including genetic polymorphisms, induction by xenobiotics, regulation by cytokines, hormones and during disease states, as well as sex, age, and others. Multiallelic genetic polymorphisms, which strongly depend on ethnicity, play a major role for the function of CYPs 2D6, 2C19, 2C9, 2B6, 3A5 and 2A6, and lead to distinct pharmacogenetic phenotypes termed as poor, intermediate, extensive, and ultrarapid metabolizers. For these CYPs, the evidence for clinical significance regarding adverse drug reactions (ADRs), drug efficacy and dose requirement is rapidly growing. Polymorphisms in CYPs 1A1, 1A2, 2C8, 2E1, 2J2, and 3A4 are generally less predictive, but new data on CYP3A4 show that predictive variants exist and that additional variants in regulatory genes or in NADPH:cytochrome P450 oxidoreductase (POR) can have an influence. Here we review the recent progress on drug metabolism activity profiles, interindividual variability and regulation of expression, and the functional and clinical impact of genetic variation in drug metabolizing P450s.
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Direct transcriptional regulation of human hepatic cytochrome P450 3A4 (CYP3A4) by peroxisome proliferator-activated receptor alpha (PPAR?).
Mol. Pharmacol.
PUBLISHED: 01-07-2013
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The nuclear receptor peroxisome proliferator-activated receptor (PPAR)? is known primarily as a regulator of fatty acid metabolism, energy balance, and inflammation, but evidence suggests a wider role in regulating the biotransformation of drugs and other lipophilic chemicals. We investigated whether PPAR? directly regulates the transcription of cytochrome P450 3A4, the major human drug-metabolizing enzyme. Using chromatin immunoprecipitation in human primary hepatocytes as well as electrophoretic mobility shift and luciferase reporter-gene assays, we identified three functional PPAR?-binding regions (PBR-I, -II, and -III) within ?12 kb of the CYP3A4 upstream sequence. Furthermore, a humanized CYP3A4/3A7 mouse model showed in vivo induction of CYP3A4 mRNA and protein by [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio]acetic acid (WY14,643) in liver but not in intestine, whereas hepatic occupancy of PBRs by PPAR? was ligand independent. Using lentiviral gene knock-down and treatment with WY14,643 in primary human hepatocytes, PPAR? was further shown to affect the expression of a distinct set of CYPs, including 1A1, 1A2, 2B6, 2C8, 3A4, and 7A1, but not 2C9, 2C19, 2D6, or 2E1. Interestingly, the common phospholipid 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine (16:0/18:1-PC), previously proposed to reflect nutritional status and shown to be a specific endogenous ligand of PPAR?, induced CYP3A4 (up to 4-fold) and other biotransformation genes in hepatocytes with similar selectivity and potency as WY14,643. These data establish PPAR? as a direct transcriptional regulator of hepatic CYP3A4. This finding warrants investigation of both known and newly developed PPAR?-targeted drugs for their drug-drug interaction potential. Furthermore, our data suggest that nutritional status can influence drug biotransformation capacity via endogenous phospholipid signaling.
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Cholestatic liver disease after rituximab and adalimumab and the possible role of cross-reacting antibodies to fab 2 fragments.
PLoS ONE
PUBLISHED: 01-01-2013
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Millions of patients are treated with therapeutic monoclonal antibodies (Tmabs) for miscellaneous diseases. We investigated sera from six patients who received immune globulin, from one patient with refractory anti-neutrophil-cytoplasmic antibody (ANCA)-associated granulomatosis with polyangiitis (GPA) who developed two episodes of acute cholestatic liver disease, one after treatment with rituximab and a second after adalimumab and a healthy control group.
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Age-dependent astroglial vulnerability to hypoxia and glutamate: the role for erythropoietin.
PLoS ONE
PUBLISHED: 01-01-2013
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Extracellular accumulation of toxic concentrations of glutamate (Glu) is a hallmark of many neurodegenerative diseases, often accompanied by hypoxia and impaired metabolism of this neuromediator. To address the question whether the multifunctional neuroprotective action of erythropoietin (EPO) extends to the regulation of extracellular Glu-level and is age-related, young and culture-aged rat astroglial primary cells (APC) were simultaneously treated with 1mM Glu and/or human recombinant EPO under normoxic and hypoxic conditions (NC and HC). EPO increased the Glu uptake by astrocytes under both NC and especially upon HC in culture-aged APC (by 60%). Moreover, treatment with EPO up-regulated the activity of glutamine synthetase (GS), the expression of glutamate-aspartate transporter (GLAST) and the level of EPO mRNA. EPO alleviated the Glu- and hypoxia-induced LDH release from astrocytes. These protective EPO effects were concentration-dependent and they were strongly intensified with age in culture. More than a 4-fold increase in apoptosis and a 2-fold decrease in GS enzyme activity was observed in APC transfected with EPO receptor (EPOR)-siRNA. Our in vivo data show decreased expression of EPO and a strong increase of EPOR in brain homogenates of APP/PS1 mice and their wild type controls during aging. Comparison of APP/PS1 and age-matched WT control mice revealed a stronger expression of EPOR but a weaker one of EPO in the Alzheimers disease (AD) model mice. Here we show for the first time the direct correlation between the extent of differentiation (age) of astrocytes and the efficacy of EPO in balancing extracellular glutamate clearance and metabolism in an in-vitro model of hypoxia and Glu-induced astroglial injury. The clinical relevance of EPO and EPOR as markers of brain cells vulnerability during aging and neurodegeneration is evidenced by remarkable changes in their expression levels in a transgenic model of AD and their WT controls.
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Genetics is a major determinant of expression of the human hepatic uptake transporter OATP1B1, but not of OATP1B3 and OATP2B1.
Genome Med
PUBLISHED: 01-01-2013
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BACKGROUND: Organic anion transporting polypeptide (OATP) 1B1, OATP1B3, and OATP2B1 (encoded by SLCO1B1, SLCO1B3, SLCO2B1) mediate the hepatic uptake of endogenous compounds like bile acids and of drugs, for example, the lipid-lowering atorvastatin, thereby influencing hepatobiliary elimination. Here we systematically elucidated the contribution of SLCO variants on expression of the three hepatic OATPs under consideration of additional important covariates. METHODS: Expression was quantified by RT-PCR and immunoblotting in 143 Caucasian liver samples. A total of 109 rare and common variants in the SLCO1B3-SLCO1B1 genomic region and the SLCO2B1 gene were genotyped by MALDI-TOF mass spectrometry and genome-wide SNP microarray technology. SLCO1B1 haplotypes affecting hepatic OATP1B1 expression were associated with pharmacokinetic data of the OATP1B1 substrate atorvastatin (n = 82). RESULTS: Expression of OATP1B1, OATP1B3, and OATP2B1 at the mRNA and protein levels showed marked interindividual variability. All three OATPs were expressed in a coordinated fashion. By a multivariate regression analysis adjusted for non-genetic and transcription covariates, increased OATP1B1 expression was associated with the coding SLCO1B1 variant c.388A > G (rs2306283) even after correction for multiple testing (P = 0.00034). This held true for haplotypes harboring c.388A > G but not the functional variant c.521T > C (rs4149056) associated with statin-related myopathy. c.388A > G also significantly affected atorvastatin pharmacokinetics. SLCO variants and non-genetic and regulatory covariates together accounted for 59% of variability of OATP1B1 expression. CONCLUSIONS: Our results show that expression of OATP1B1, but not of OATP1B3 and OATP2B1, is significantly affected by genetic variants. The SLCO1B1 variant c.388A > G is the major determinant with additional consequences on atorvastatin plasma levels.
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Genetic polymorphism of cytochrome P450 2D6 determines oestrogen receptor activity of the major infertility drug clomiphene via its active metabolites.
Hum. Mol. Genet.
PUBLISHED: 11-22-2011
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Clomiphene citrate is the most used drug for the treatment of female infertility, a common condition in western societies and developing countries. Despite dose escalation, up to 30% of women do not respond. Since clomiphene shares structural similarities with tamoxifen, which is predominantly bioactivated by the polymorphic cytochrome P450 (CYP) 2D6, we systematically explored clomiphene metabolism and action in vitro and in vivo by pharmacogenetic, -kinetic and -dynamic investigations. Human liver microsomes were incubated with clomiphene citrate and nine metabolites were identified by mass spectrometry and tested at the oestrogen receptor for their antagonistic capacity. (E)-4-hydroxyclomiphene and (E)-4-hydroxy-N-desethylclomiphene showed strongest inhibition of the oestrogen receptor activity with 50% inhibitory concentrations of 2.5 and 1.4 nm, respectively. CYP2D6 has been identified as the major enzyme involved in their formation using recombinant CYP450 isozymes as confirmed by inhibition experiments with CYP monoclonal antibodies. We correlated the CYP2D6 genotype of 30 human liver donors with the microsomal formation rate of active metabolites and observed a strong gene-dose effect. A healthy female volunteer study confirmed our in vitro data that the CYP2D6 polymorphism substantially determines the formation of the active clomiphene metabolites. Comparison of the C(max) of (E)-4-hydroxyclomiphene and (E)-4-hydroxy-N-desethylclomiphene showed 8 and 12 times lower concentrations in subjects with non-functional CYP2D6 alleles. Our results highlight (E)-4-hydroxyclomiphene and (E)-4-hydroxy-N-desethylclomiphene as the active clomiphene metabolites, the formation of which strongly depends on the polymorphic CYP2D6 enzyme. Our data provide first evidence of a biological rationale for the variability in the response to clomiphene treatment.
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DNA methylation is associated with downregulation of the organic cation transporter OCT1 (SLC22A1) in human hepatocellular carcinoma.
Genome Med
PUBLISHED: 10-13-2011
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Organic cation transporters (OCTs) determine not only physiological processes but are also involved in the cellular uptake of anticancer agents. Based on microarray analyses in hepatocellular carcinoma (HCC), SLC22A1/OCT1 mRNA seems to be downregulated, but systematic protein expression data are currently missing. Moreover, the underlying molecular mechanisms responsible for altered SLC22A1 expression in HCC are not fully understood. Therefore, we investigated the role of DNA methylation in the transcriptional regulation of the family members SLC22A1/OCT1, SLC22A2/OCT2 and SLC22A3/OCT3 in HCC.
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Mammalian MATE (SLC47A) transport proteins: impact on efflux of endogenous substrates and xenobiotics.
Drug Metab. Rev.
PUBLISHED: 09-17-2011
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Multidrug and toxin extrusion proteins (MATEs; SLC47A) are mammalian transporters being predominately expressed in the brush-border membrane of proximal tubule epithelial cells in the kidney and the canalicular membrane of hepatocytes. Functionally, MATEs act as efflux transporters for organic compounds, thereby mediating the elimination process. Two isoforms, MATE1 and 2, have been identified, and, so far, only a limited number of substrates, including clinically used drugs such as metformin and cimetidine, are known. A knockout mouse model has been established, as well, and is a valuable tool for further systematic pharmacokinetic analyses. In this review, we summarize the progress in MATE research on structural, molecular, functional, and pathophysiological aspects. Consequences of genetic variants for pharmacokinetic alterations and drug therapy are discussed.
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Developmental pharmacokinetics.
Handb Exp Pharmacol
PUBLISHED: 09-02-2011
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The advances in developmental pharmacokinetics during the past decade reside with an enhanced understanding of the influence of growth and development on drug absorption, distribution, metabolism, and excretion (ADME). However, significant information gaps remain with respect to our ability to characterize the impact of ontogeny on the activity of important drug metabolizing enzymes, transporters, and other targets. The ultimate goal of rational drug therapy in neonates, infants, children, and adolescents resides with the ability to individualize it based on known developmental differences in drug disposition and action. The clinical challenge in achieving this is accounting for the variability in all of the contravening factors that influence pharmacokinetics and pharmacodynamics (e.g., genetic variants of ADME genes, different disease phenotypes, disease progression, and concomitant treatment). Application of novel technologies in the fields of pharmacometrics (e.g., in silico simulation of exposure-response relationships; disease progression modeling), pharmacogenomics and biomarker development (e.g., creation of pharmacodynamic surrogate endpoints suitable for pediatric use) are increasingly making integrated approaches for developmentally appropriate dose regimen selection possible.
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Glucocorticoid exposure of sheep at 0.7 to 0.75 gestation augments late-gestation fetal stress responses.
Am. J. Obstet. Gynecol.
PUBLISHED: 08-25-2011
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Exposure to glucocorticoid levels inappropriately high for current maturation alters fetal hypothalamo-pituitary-adrenal axis (HPAA) development. In an established fetal sheep model, we determined whether clinical betamethasone doses used to accelerate fetal lung maturation have persistent effects on fetal HPAA hypotensive-stress responses.
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Preparation of microporous melamine-based polymer networks in an anhydrous high-temperature miniemulsion.
Macromol Rapid Commun
PUBLISHED: 08-01-2011
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We report the first example of a successful preparation of a microporous organic polymer within the droplet phase of an inverse non-aqueous miniemulsion. Stable nanoparticles with enhanced specific surface area could be obtained despite the harsh conditions regarding reaction temperature (180 °C) and time (72 h) needed for building melamine-based Schiff base networks. Our new flexible method can in principle be applied to other water-sensitive protocols suitable for the bulk synthesis of MOPs that are based on Friedel-Crafts, Sonogashira-Hagihara or Yamamoto chemistry.
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A new molecular predictor of distant recurrence in ER-positive, HER2-negative breast cancer adds independent information to conventional clinical risk factors.
Clin. Cancer Res.
PUBLISHED: 08-01-2011
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According to current guidelines, molecular tests predicting the outcome of breast cancer patients can be used to assist in making treatment decisions after consideration of conventional markers. We developed and validated a gene expression signature predicting the likelihood of distant recurrence in patients with estrogen receptor (ER)-positive, HER2-negative breast cancer treated with adjuvant endocrine therapy.
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The earwax-associated SNP c.538G>A (G180R) in ABCC11 is not associated with breast cancer risk in Europeans.
Breast Cancer Res. Treat.
PUBLISHED: 05-23-2011
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Genetic polymorphisms of human ABC-transporter genes have been suggested to modulate breast cancer risk in the general population. In particular ABCC11 (MRP8), which is highly expressed in breast cancer tissue and involved in the efflux of conjugated estrogen metabolites such as estrone-3-sulfate and estradiol-17beta-glucuronide, has recently been proposed as a potential risk factor for female breast cancer. The wet earwax-associated G-allele of the c.538G>A polymorphism was associated with an increased risk for breast cancer in Japanese women. In contrast, no evidence for such an association could be observed in Caucasian women. We aimed to confirm/refute the association of the c.538G>A variant in ABCC11 with breast cancer risk and/or histo-pathological tumor characteristics in an independent population-based breast cancer case-control study from Germany comprising 1021 cases and 1015 age-matched controls. No association for allele and genotype frequencies of the 538G>A variant in ABCB11 with breast cancer risk was found. Our data suggest that the c.538G>A variation in ABCC11 does not contribute to breast carcinogenesis in women of European descent.
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Paraoxonase (PON1 and PON3) Polymorphisms: Impact on Liver Expression and Atorvastatin-Lactone Hydrolysis.
Front Pharmacol
PUBLISHED: 05-03-2011
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Atorvastatin ?-lactone, a major, pharmacologically inactive metabolite, has been associated with toxicity. In a previous study we showed that polymorphisms of UGT1A3 influence atorvastatin ?-lactone formation. Here we investigated the reverse reaction, atorvastatin ?-lactone hydrolysis, in a human liver bank. Screening of microarray data revealed paraoxonases PON1 and PON3 among 17 candidate esterases. Microsomal ?-lactone hydrolysis was significantly correlated to PON1 and PON3 protein (r(s)?=?0.60; r(s)?=?0.62, respectively; P??C, -832G?>?A, -1741G?>?A) and a tightly linked group of PON3 polymorphisms (-4984A?>?G, -4105G?>?A, -1091A?>?G, -746C?>?T, and F21F) to be associated with changes in atorvastatin ?-lactone hydrolysis and expression of PON1 but not PON3. However, carriers of the common PON1 polymorphisms L55M or Q192R showed no difference in ?-lactone hydrolysis or PON expression. Haplotype analysis revealed decreased ?-lactone hydrolysis in carriers of the most common haplotype *1 compared to carriers of haplotypes *2, *3, *4, and *7. Analysis of non-genetic factors showed association of hepatocellular and cholangiocellular carcinoma with decreased PON1 and PON3 expression, respectively. Increased C-reactive protein and ?-glutamyl transferase levels were associated with decreased protein expression of both enzymes, and increased bilirubin levels, cholestasis, and presurgical exposure to omeprazole or pantoprazole were related to decreased PON3 protein. In conclusion, PON-locus polymorphisms affect PON1 expression whereas non-genetic factors have an effect on PON1 and PON3 expression. This may influence response to therapy or adverse events in statin treatment.
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Proton pump inhibitors inhibit metformin uptake by organic cation transporters (OCTs).
PLoS ONE
PUBLISHED: 04-06-2011
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Metformin, an oral insulin-sensitizing drug, is actively transported into cells by organic cation transporters (OCT) 1, 2, and 3 (encoded by SLC22A1, SLC22A2, or SLC22A3), which are tissue specifically expressed at significant levels in various organs such as liver, muscle, and kidney. Because metformin does not undergo hepatic metabolism, drug-drug interaction by inhibition of OCT transporters may be important. So far, comprehensive data on the interaction of proton pump inhibitors (PPIs) with OCTs are missing although PPIs are frequently used in metformin-treated patients. Using in silico modeling and computational analyses, we derived pharmacophore models indicating that PPIs (i.e. omeprazole, pantoprazole, lansoprazole, rabeprazole, and tenatoprazole) are potent OCT inhibitors. We then established stably transfected cell lines expressing the human uptake transporters OCT1, OCT2, or OCT3 and tested whether these PPIs inhibit OCT-mediated metformin uptake in vitro. All tested PPIs significantly inhibited metformin uptake by OCT1, OCT2, and OCT3 in a concentration-dependent manner. Half-maximal inhibitory concentration values (IC(50)) were in the low micromolar range (3-36 µM) and thereby in the range of IC(50) values of other potent OCT drug inhibitors. Finally, we tested whether the PPIs are also transported by OCTs, but did not identify PPIs as OCT substrates. In conclusion, PPIs are potent inhibitors of the OCT-mediated metformin transport in vitro. Further studies are needed to elucidate the clinical relevance of this drug-drug interaction with potential consequences on metformin disposition and/or efficacy.
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Practical recommendations for pharmacogenomics-based prescription: 2010 ESF-UB Conference on Pharmacogenetics and Pharmacogenomics.
Pharmacogenomics
PUBLISHED: 04-05-2011
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The present article summarizes the discussions of the 3rd European Science Foundation-University of Barcelona (ESF-UB) Conference in Biomedicine on Pharmacogenetics and Pharmacogenomics, which was held in June 2010 in Spain. It was focused on practical applications in routine medical practice. We provide practical recommendations for ten different clinical situations, that have either been approved or not approved by regulatory agencies. We propose some comments that might accompany the results of these tests, indicating the best drug and doses to be prescribed. The discussed examples include KRAS, cetuximab, panitumumab, EGFR-gefitinib, CYP2D6-tamoxifen, TPMT-azathioprine-6-mercaptopurine, VKORC1/CYP2C9-warfarin, CYP2C19-clopidogrel, HLA-B*5701-abacavir, HLA-B*5701-flucloxacillin, SLCO1B1-statins and CYP3A5-tacrolimus. We hope that these practical recommendations will help physicians, biologists, scientists and other healthcare professionals to prescribe, perform and interpret these genetic tests.
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Molecular triangles: synthesis, self-assembly, and blue emission of cyclo-7,10-tris-triphenylenyl macrocycles.
Chem Asian J
PUBLISHED: 03-13-2011
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A set of cyclo-7,10-tris-triphenylenyl macrocycles have been prepared by a Yamamoto cyclotrimerization protocol. In these novel macrocycles, three triphenylene units are covalently linked to each other, resulting in the formation of triangular-shaped molecules. The fully planar derivative revealed pronounced self-assembly behavior. NMR spectroscopy was used to determine the association constant in solution. 2D wide-angle X-ray scattering was applied to the study of the liquid crystallinity of this new discotic mesogen in the bulk state. Furthermore, nonplanar, laterally substituted derivatives were successfully tested as blue emitters in organic light-emitting diodes owing to their unique optoelectronic properties and their high stability. In this case, substitution with sterically demanding phenyl groups was efficiently used to suppress intermolecular packing, thus preventing undesired quenching effects.
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Organic cation transporters (OCTs, MATEs), in vitro and in vivo evidence for the importance in drug therapy.
Handb Exp Pharmacol
PUBLISHED: 02-26-2011
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Organic cation transporters (OCTs) of the solute carrier family (SLC) 22 and multidrug and toxin extrusion (MATE) transporters of the SLC47 family have been identified as uptake and efflux transporters, respectively, for xenobiotics including several clinically used drugs such as the antidiabetic agent metformin, the antiviral agent lamivudine, and the anticancer drug oxaliplatin. Expression of human OCT1 (SLC22A1) and OCT2 (SLC22A2) is highly restricted to the liver and kidney, respectively. By contrast, OCT3 (SLC22A3) is more widely distributed. MATEs (SLC47A1, SLC47A2) are predominantly expressed in human kidney. Data on in vitro studies reporting a large number of substrates and inhibitors of OCTs and MATEs are systematically summarized. Several genetic variants of human OCTs and in part of MATE1 have been reported, and some of them result in reduced in vitro transport activity corroborating data from studies with knockout mice. A comprehensive overview is given on currently known genotype-phenotype correlations for variants in OCTs and MATE1 related to protein expression, pharmacokinetics/-dynamics of transporter substrates, treatment outcome, and disease susceptibility.
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Oncogenic stress induced by acute hyper-activation of Bcr-Abl leads to cell death upon induction of excessive aerobic glycolysis.
PLoS ONE
PUBLISHED: 02-18-2011
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In response to deregulated oncogene activation, mammalian cells activate disposal programs such as programmed cell death. To investigate the mechanisms behind this oncogenic stress response we used Bcr-Abl over-expressing cells cultivated in presence of imatinib. Imatinib deprivation led to rapid induction of Bcr-Abl activity and over-stimulation of PI3K/Akt-, Ras/MAPK-, and JAK/STAT pathways. This resulted in a delayed necrosis-like cell death starting not before 48 hours after imatinib withdrawal. Cell death was preceded by enhanced glycolysis, glutaminolysis, and amino acid metabolism leading to elevated ATP and protein levels. This enhanced metabolism could be linked to induction of cell death as inhibition of glycolysis or glutaminolysis was sufficient to sustain cell viability. Therefore, these data provide first evidence that metabolic changes induced by Bcr-Abl hyper-activation are important mediators of oncogenic stress-induced cell death.During the first 30 hours after imatinib deprivation, Bcr-Abl hyper-activation did not affect proliferation but resulted in cellular swelling, vacuolization, and induction of eIF2? phosphorylation, CHOP expression, as well as alternative splicing of XPB, indicating endoplasmic reticulum stress response. Cell death was dependent on p38 and RIP1 signaling, whereas classical death effectors of ER stress, namely CHOP-BIM were antagonized by concomitant up-regulation of Bcl-xL.Screening of 1,120 compounds for their potential effects on oncogenic stress-induced cell death uncovered that corticosteroids antagonize cell death upon Bcr-Abl hyper-activation by normalizing cellular metabolism. This protective effect is further demonstrated by the finding that corticosteroids rendered lymphocytes permissive to the transforming activity of Bcr-Abl. As corticosteroids are used together with imatinib for treatment of Bcr-Abl positive acute lymphoblastic leukemia these data could have important implications for the design of combination therapy protocols.In conclusion, excessive induction of Warburg type metabolic alterations can cause cell death. Our data indicate that these metabolic changes are major mediators of oncogenic stress induced by Bcr-Abl.
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Therapeutic efficacy of intranasally delivered mesenchymal stem cells in a rat model of Parkinson disease.
Rejuvenation Res
PUBLISHED: 02-03-2011
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Safe and effective cell delivery remains one of the main challenges in cell-based therapy of neurodegenerative disorders. Graft survival, sufficient enrichment of therapeutic cells in the brain, and avoidance of their distribution throughout the peripheral organs are greatly influenced by the method of delivery. Here we demonstrate for the first time noninvasive intranasal (IN) delivery of mesenchymal stem cells (MSCs) to the brains of unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats. IN application (INA) of MSCs resulted in the appearance of cells in the olfactory bulb, cortex, hippocampus, striatum, cerebellum, brainstem, and spinal cord. Out of 1?×?10? MSCs applied intranasally, 24% survived for at least 4.5 months in the brains of 6-OHDA rats as assessed by quantification of enhanced green fluorescent protein (EGFP) DNA. Quantification of proliferating cell nuclear antigen-positive EGFP-MSCs showed that 3% of applied MSCs were proliferative 4.5 months after application. INA of MSCs increased the tyrosine hydroxylase level in the lesioned ipsilateral striatum and substantia nigra, and completely eliminated the 6-OHDA-induced increase in terminal deoxynucleotidyl transferase (TdT)-mediated 2-deoxyuridine, 5-triphosphate (dUTP)-biotin nick end labeling (TUNEL) staining of these areas. INA of EGFP-labeled MSCs prevented any decrease in the dopamine level in the lesioned hemisphere, whereas the lesioned side of the control animals revealed significantly lower levels of dopamine 4.5 months after 6-OHDA treatment. Behavioral analyses revealed significant and substantial improvement of motor function of the Parkinsonian forepaw to up to 68% of the normal value 40-110 days after INA of 1?×?10? cells. MSC-INA decreased the concentrations of inflammatory cytokines-interleukin-1? (IL-1?), IL-2, -6, -12, tumor necrosis factor (TNF), interferon-? (IFN-?, and granulocyte-macrophage colony-stimulating factor (GM-CSF)-in the lesioned side to their levels in the intact hemisphere. IN administration provides a highly promising noninvasive alternative to the traumatic surgical procedure of transplantation and allows targeted delivery of cells to the brain with the option of chronic application.
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Quantification of clomiphene metabolite isomers in human plasma by rapid-resolution liquid chromatography-electrospray ionization-tandem mass spectrometry.
Anal Bioanal Chem
PUBLISHED: 02-01-2011
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Since the 1960s, clomiphene citrate is used for ovulation induction. Since nonresponse to clomiphene therapy is still not well understood, interindividual variability of clomiphene metabolism has been considered to be a plausible explanation. Therefore, a comprehensive, rapid, sensitive, and specific analytical method for the quantification of (E)- and (Z)-isomers of clomiphene and their putative N-desethyl, N,N-didesethyl, 4-hydroxy, and 4-hydroxy-N-desethyl metabolites, and the N-oxides in human plasma has been newly developed, using HPLC-tandem mass spectrometry and stable isotope-labeled internal standards. All standards other than the parent drug were synthesized in our laboratory. Following protein precipitation analytes were separated on a ZORBAX Eclipse plus C18 1.8 ?m column with a gradient of 0.1% formic acid in water and 0.1% formic acid in acetonitrile and detected on a triple quadrupole mass spectrometer with positive electrospray ionization in the multiple reaction monitoring mode. Lower limit of quantification for metabolites ranged from 0.06 ng/mL for clomiphene-N-oxides to 0.3 ng/mL for (E)-N-desethylclomiphene. The assay was validated according to FDA guidelines. Plasma levels of clomiphene and its metabolites were measured in two women after single-dose treatment with clomiphene.
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Vulnerability of the fetal primate brain to moderate reduction in maternal global nutrient availability.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 01-20-2011
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Moderate maternal nutrient restriction during pregnancy occurs in both developing and developed countries. In addition to poverty, maternal dieting, teenage pregnancy, and uterine vascular problems in older mothers are causes of decreased fetal nutrition. We evaluated the impact of global 30% maternal nutrient reduction (MNR) on early fetal baboon brain maturation. MNR induced major cerebral developmental disturbances without fetal growth restriction or marked maternal weight reduction. Mechanisms evaluated included neurotrophic factor suppression, cell proliferation and cell death imbalance, impaired glial maturation and neuronal process formation, down-regulation of gene ontological pathways and related gene products, and up-regulated transcription of cerebral catabolism. Contrary to the known benefits from this degree of dietary reduction on life span, MNR in pregnancy compromises structural fetal cerebral development, potentially having an impact on brain function throughout life.
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Photocatalytic hydrogen evolution through fully conjugated poly(azomethine) networks.
Chem. Commun. (Camb.)
PUBLISHED: 11-02-2010
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Three-dimensional conjugated poly(azomethine) networks were found to be promising candidates for applications in photocatalytic water splitting. Straightforward synthetic protocols lead to fully organic photocatalysts that showed enhanced long-time stability. Furthermore, the catalytic performance of these materials was correlated to the molecular composition and the optoelectronic properties of the samples.
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Automated extraction of DNA and RNA from a single formalin-fixed paraffin-embedded tissue section for analysis of both single-nucleotide polymorphisms and mRNA expression.
Clin. Chem.
PUBLISHED: 10-14-2010
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There is an increasing need for the identification of both DNA and RNA biomarkers from pathodiagnostic formalin-fixed paraffin-embedded (FFPE) tissue samples for the exploration of individualized therapy strategies in cancer. We investigated a fully automated, xylene-free nucleic acid extraction method for the simultaneous analysis of RNA and DNA biomarkers related to breast cancer.
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