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https://www.readbyqxmd.com/read/28212467/comparison-of-6-mercaptopurine-with-6-thioguanine-for-the-analysis-of-thiopurine-s-methyltransferase-activity-in-human-erythrocyte-by-lc-ms-ms
#1
Shenghui Mei, Xindi Li, Xiaoqing Gong, Xiaoyi Zhang, Xingang Li, Li Yang, Leting Zhu, Heng Zhou, Yonghong Liu, Anna Zhou, Xinghu Zhang, Zhigang Zhao
Thiopurines (TPDs) are first-line drugs in treating neuromyelitis optica spectrum disorders (NMOSD). Thiopurine S-methyltransferase activity (TPMT), a major determinant of TPDs toxicity, was suggested to be evaluated before TPDs treatment by using 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG) as substrate. However, the equivalent of the two substrates in TPMT activity evaluation was unknown, and alternative substrate was required in TPMT activity evaluation in patients who were already taking 6-MP or 6-TG...
February 17, 2017: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/28172435/p154-complete-sequence-based-nudt15-and-tpmt-variants-for-predicting-thiopurine-induced-leukopenia-in-patients-with-crohn-s-disease
#2
T J Kim, E R Kim, S N Hong, D K Chang, Y-H Kim
No abstract text is available yet for this article.
February 1, 2017: Journal of Crohn's & Colitis
https://www.readbyqxmd.com/read/28153823/comparison-of-self-report-and-electronic-monitoring-of-6mp-intake-in-childhood-all-a-children-s-oncology-group-study
#3
Wendy Landier, Yanjun Chen, Lindsey Hageman, Heeyoung Kim, Bruce C Bostrom, Jacqueline N Casillas, David S Dickens, William E Evans, Kelly W Maloney, Leo Mascarenhas, A Kim Ritchey, Amanda M Termuhlen, William L Carroll, Mary V Relling, F Lennie Wong, Smita Bhatia
Adequate exposure to oral 6-mercaptopurine (6MP) during maintenance therapy for childhood acute lymphoblastic leukemia (ALL) is critical for sustaining durable remissions; the accuracy of self-reported 6MP intake is unknown. We aimed to directly compare self-report to electronic monitoring (Medication Event Monitoring System [MEMS]), and identify predictors of over-reporting in a cohort of 416 children with ALL in first remission over 4 study months per patient (1,344 patient-months for the cohort) during maintenance therapy...
February 2, 2017: Blood
https://www.readbyqxmd.com/read/28140508/identifying-unknown-enzyme-substrate-pairs-from-the-cellular-milieu-with-native-mass-spectrometry
#4
Kalli C Catcott, Jing Yan, Wanlu Qu, Vicki H Wysocki, Zhaohui Sunny Zhou
The enzyme-substrate complex is inherently transient, rendering its detection difficult. In our framework, IsoLAIT (Isotope-Labeled, Activity-based Identification and Tracking), designed for bisubstrate systems, the common substrate, such as S-adenosyl-L-methionine (AdoMet) for methyltransferases, is replaced by an analogue (e.g., S-adenosyl-L-vinthionine) that, as a probe, creates a tightly bound [enzyme*substrate-probe] complex upon catalysis by thiopurine-S-methyltransferase (TPMT, EC 2.1.1.67). Then, this persistent complex is identified by native mass spectrometry from the cellular milieu without separation...
January 31, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28110955/determination-of-inosine-5-monophosphate-dehydrogenase-activity-in-red-blood-cells-of-thiopurine-treated-patients-using-hplc
#5
Audrey Beringer, Antony Citterio-Quentin, Rebeca Obenza Otero, Clémence Gustin, Rebecca Clarke, Jean-Paul Salvi, Roselyne Boulieu
Thiopurine drugs are commonly used in immune diseases and to a lesser extent, in transplant rejection prophylaxis: however interindividual variability in drug response and in the occurrence of adverse events is observed. Genetic variation in thiopurine S-methyltransferase (TPMT) doesn't completely explain the occurrence of all adverse events and drug response variability. The potential implication of other enzymes involved in thiopurine metabolism, such as ITPA, has been investigated over the last decade but little data is available on inosine 5'-monophosphate dehydrogenase (IMPDH) in patients treated with thiopurine drugs...
February 15, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28081040/azathioprine-therapy-in-a-pediatric-tpmt-deficient-patient-still-an-option
#6
S A W van Moorsel, N Bevers, M Meurs, L K van Rossum, P M Hooymans, D R Wong
We describe the case of a pediatric patient on azathioprine therapy with previously undiagnosed homozygote thiopurine S-methyltransferase (TPMT) deficiency, resulting in myelotoxic thiopurine metabolite levels. The patient was successfully treated with a very low azathioprine dose of 50 mg once a week (4% of standard dose), guided by frequent thiopurine metabolite measurement and a close clinical surveillance. We demonstrate that azathioprine therapy still might be an effective and safe therapeutic option in pediatric thiopurine S-methyltransferase-deficient IBD patients...
February 2017: Therapeutic Drug Monitoring
https://www.readbyqxmd.com/read/28060115/hepatotoxicity-during-maintenance-therapy-and-prognosis-in-children-with-acute-lymphoblastic-leukemia
#7
Maria S Ebbesen, Ulrikka Nygaard, Susanne Rosthøj, Ditte Sørensen, Jacob Nersting, Kim Vettenranta, Finn Wesenberg, Jon Kristinsson, Arja Harila-Saari, Kjeld Schmiegelow
Hepatotoxicity is a known toxicity to treatment of childhood acute lymphoblastic leukemia. Hepatotoxicity occurs during maintenance therapy and is caused by metabolites of 6-Mercaptopurine (6 MP) and Methotrexate (MTX). Our objective was to investigate the association between alanine aminotransferases (ALAT) levels and relapse rate. We included 385 patients enrolled in the NOPHO ALL-92 protocol. Data on ALAT levels, 6 MP and MTX doses, cytotoxic MTX/6 MP metabolites, and thiopurine methyltransferase (TPMT) activity were prospectively registered...
January 5, 2017: Journal of Pediatric Hematology/oncology
https://www.readbyqxmd.com/read/27941536/lc-ms-ms-analysis-of-erythrocyte-thiopurine-nucleotides-and-their-association-with-genetic-variants-in-patients-with-neuromyelitis-optica-spectrum-disorders-taking-azathioprine
#8
Shenghui Mei, Xindi Li, Xiaoqing Gong, Xingang Li, Li Yang, Heng Zhou, Yonghong Liu, Anna Zhou, Leting Zhu, Xinghu Zhang, Zhigang Zhao
BACKGROUND: Azathioprine (AZA) is a first-line drug in treating neuromyelitis optica spectrum disorders (NMOSD). To exhibit its bioactivity, AZA needs to be converted to thiopurine nucleotides (TPNs) including 6-thioguanine nucleotides (6-TGNs) and 6-methylmercaptopurine nucleotides (6-MMPNs) that are affected by genetic polymorphisms. This study aims to develop an LC-MS/MS method for the analysis of erythrocyte concentrations of TPNs and to evaluate their associations with variants of various genes (MTHFR, TPMT, HLA, SLC29A1, SLC28A2, SLC28A3, ABCB1 and ABCC4) in patients with NMOSD...
November 29, 2016: Therapeutic Drug Monitoring
https://www.readbyqxmd.com/read/27920553/meta-analysis-of-the-impact-of-thioprine-s-methyltransferase-polymorphisms-on-the-tolerable-6-mercaptopurine-dose-considering-initial-dose-and-ethnic-difference
#9
Myeong Gyu Kim, Minoh Ko, In-Wha Kim, Jung Mi Oh
A meta-analysis was conducted to decide whether to reduce an initial 6-mercaptopurine (6-MP) dose in TPMT heterozygote in the case of an initial 6-MP dose of <75 mg/m(2)/d and to compare the tolerable 6-MP dose among different ethnic groups. The study was undertaken according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The differences in mean values of the tolerable 6-MP dose were calculated by using Comprehensive Meta-Analysis version 3. The results of the meta-analysis indicated that the tolerable 6-MP dose was significantly lower in the TPMT heterozygote group (difference in mean values =11...
2016: OncoTargets and Therapy
https://www.readbyqxmd.com/read/27809554/mercaptopurine-and-inflammatory-bowel-disease-the-other-thiopurine
#10
Fernando Bermejo San José, Alicia Algaba, Sergio López Durán, Iván Guerra, Marta Aicart, María Hernández-Tejero, Elena Garrido, María de Lucas, Daniel Bonillo, Antonio López Sanromán
BACKGROUND: Data about use and effectiveness of mercaptopurine in inflammatory bowel disease are relatively limited. AIMS: To assess the possible therapeutic indications, efficacy and safety of mercaptopurine as an alternative to azathioprine in inflammatory bowel disease. METHODS: Retrospective observational study in patients treated with mercaptopurine in a total cohort of 1,574 patients with inflammatory bowel disease. RESULTS: One hundred and fifty-two patients received mercaptopurine, 15...
January 2017: Revista Española de Enfermedades Digestivas
https://www.readbyqxmd.com/read/27770449/polymorphic-variation-in-tpmt-is-the-principal-determinant-of-tpmt-phenotype-a-meta-analysis-of-three-genome-wide-association-studies
#11
R Tamm, R Mägi, R Tremmel, S Winter, E Mihailov, A Smid, A Möricke, K Klein, M Schrappe, M Stanulla, R Houlston, R Weinshilboum, Irena Mlinarič Raščan, A Metspalu, L Milani, M Schwab, E Schaeffeler
Thiopurine-related hematotoxicity in pediatric acute lymphoblastic leukemia (ALL) and inflammatory bowel diseases has been linked to genetically defined variability in thiopurine S-methyltransferase (TPMT) activity. While gene testing of TPMT is being clinically implemented, it is unclear if additional genetic variation influences TPMT activity with consequences for thiopurine-related toxicity. To examine this possibility, we performed a genome-wide association study (GWAS) of red blood cell TPMT activity in 844 Estonian individuals and 245 pediatric ALL cases...
October 22, 2016: Clinical Pharmacology and Therapeutics
https://www.readbyqxmd.com/read/27729156/analysis-of-genetic-and-non-genetic-risk-factors-for-cisplatin-ototoxicity-in-pediatric-patients
#12
Yüksel Olgun, Safiye Aktaş, Zekiye Altun, Günay Kırkım, Deniz Çakır Kızmazoğlu, Ayşe Pınar Erçetin, Banu Demir, Dilek İnce, Kamer Mutafoğlu, Bengü Demirağ, Hülya Ellidokuz, Nur Olgun, Enis Alpin Güneri
OBJECTIVE: The aim of this study was to analyse the genetic and non genetic risk factors for cisplatin ototoxicity. METHODS: This study was conducted on 72 children who received cisplatin based chemotherapy. Brock and Muenster classifications were used to evaluate ototoxicity seen in these children. 6 single nucleotide polymorphisms (SNP); ERCC1 rs 11615, GSTP1 rs1138272, GSTP1 rs1695, LRP2 rs 2075252, TPMT rs 12201199, COMT rs 9332377, were evaluated as genetic factors by real time PCR...
November 2016: International Journal of Pediatric Otorhinolaryngology
https://www.readbyqxmd.com/read/27703193/genes-implicated-in-thiopurine-induced-toxicity-comparing-tpmt-enzyme-activity-with-clinical-phenotype-and-exome-data-in-a-paediatric-ibd-cohort
#13
Tracy Coelho, Gaia Andreoletti, James J Ashton, Akshay Batra, Nadeem Ahmad Afzal, Yifang Gao, Anthony P Williams, Robert M Beattie, Sarah Ennis
The aim of our study was to assess the utility of next generation sequencing (NGS) for predicting toxicity and clinical response to thiopurine drugs in paediatric patients with inflammatory bowel disease. Exome data for 100 patients were assessed against biochemically measured TPMT enzyme activity, clinical response and adverse effects. The TPMT gene and a panel of 15 other genes implicated in thiopurine toxicity were analysed using a gene based statistical test (SKAT-O test). Nine patients out of 100 (Crohn's disease- 67, ulcerative colitis- 23 and IBDU-10) had known TPMT mutations associated with deficient enzyme activity...
October 5, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27665263/frequency-of-thiopurine-methyltransferase-mutation-in-patients-of-mediterranean-area-with-inflammatory-bowel-disease-and-autoimmune-disorders
#14
Angela Di Salvo, Carmelo Fabiano, Vincenza Mannara, Mariangela Dimarco, Ambrogio Orlando, Marco Affronti, Fabio Salvatore Macaluso, Mario Cottone
BACKGROUND AND AIMS: Few studies exist on the frequency of thiopurine methyltransferase (TPMT) mutation in patients from Southern Europe. We aimed to evaluate the frequency of TPMT mutation in a homogeneous Sicilian cohort of patients with inflammatory bowel disease (IBD), autoimmune and hematological disorders, the rate of thiopurine-related adverse events, and its association with the TPMT genotype. RESULTS: Among 105 patients with IBD, 45 with autoimmune disease, and 34 with hematologic diseases, the homozygous TPMT variant genotype was found in one patient only (0...
December 2016: Digestive and Liver Disease
https://www.readbyqxmd.com/read/27641154/genotypes-affecting-the-pharmacokinetics-of-anticancer-drugs
#15
Daphne Bertholee, Jan Gerard Maring, André B P van Kuilenburg
Cancer treatment is becoming more and more individually based as a result of the large inter-individual differences that exist in treatment outcome and toxicity when patients are treated using population-based drug doses. Polymorphisms in genes encoding drug-metabolizing enzymes and transporters can significantly influence uptake, metabolism, and elimination of anticancer drugs. As a result, the altered pharmacokinetics can greatly influence drug efficacy and toxicity. Pharmacogenetic screening and/or drug-specific phenotyping of cancer patients eligible for treatment with chemotherapeutic drugs, prior to the start of anticancer treatment, can identify patients with tumors that are likely to be responsive or resistant to the proposed drugs...
September 19, 2016: Clinical Pharmacokinetics
https://www.readbyqxmd.com/read/27640357/measuring-erythrocyte-thiopurine-methyltransferase-activity-in-children-is-it-helpful
#16
Alison L T Ma, Gregory Bale, Helen Aitkenhead, Stephen D Marks
OBJECTIVE: To assess the profile of thiopurine transmethyltransferase (TPMT) enzyme activities in children and discuss the utility of measuring TPMT levels before commencing azathioprine therapy. STUDY DESIGN: Retrospective study in a single pediatric center of all patients who had TPMT enzyme assay measured during a 3-year period before the start of azathioprine therapy. Patients' TPMT enzyme activities were classified as normal (26-50 pmol/h/mgHb), intermediate (10-25 pmol/h/mgHb), and deficient (<10 pmol/h/mgHb)...
September 15, 2016: Journal of Pediatrics
https://www.readbyqxmd.com/read/27636550/a-european-spectrum-of-pharmacogenomic-biomarkers-implications-for-clinical-pharmacogenomics
#17
Clint Mizzi, Eleni Dalabira, Judit Kumuthini, Nduna Dzimiri, Istvan Balogh, Nazli Başak, Ruwen Böhm, Joseph Borg, Paola Borgiani, Nada Bozina, Henrike Bruckmueller, Beata Burzynska, Angel Carracedo, Ingolf Cascorbi, Constantinos Deltas, Vita Dolzan, Anthony Fenech, Godfrey Grech, Vytautas Kasiulevicius, Ľudevít Kádaši, Vaidutis Kučinskas, Elza Khusnutdinova, Yiannis L Loukas, Milan Macek, Halyna Makukh, Ron Mathijssen, Konstantinos Mitropoulos, Christina Mitropoulou, Giuseppe Novelli, Ioanna Papantoni, Sonja Pavlovic, Giuseppe Saglio, Jadranka Setric, Maja Stojiljkovic, Andrew P Stubbs, Alessio Squassina, Maria Torres, Marek Turnovec, Ron H van Schaik, Konstantinos Voskarides, Salma M Wakil, Anneke Werk, Maria Del Zompo, Branka Zukic, Theodora Katsila, Ming Ta Michael Lee, Alison Motsinger-Rief, Howard L Mc Leod, Peter J van der Spek, George P Patrinos
Pharmacogenomics aims to correlate inter-individual differences of drug efficacy and/or toxicity with the underlying genetic composition, particularly in genes encoding for protein factors and enzymes involved in drug metabolism and transport. In several European populations, particularly in countries with lower income, information related to the prevalence of pharmacogenomic biomarkers is incomplete or lacking. Here, we have implemented the microattribution approach to assess the pharmacogenomic biomarkers allelic spectrum in 18 European populations, mostly from developing European countries, by analyzing 1,931 pharmacogenomics biomarkers in 231 genes...
2016: PloS One
https://www.readbyqxmd.com/read/27604507/nudt15-polymorphisms-are-better-than-thiopurine-s-methyltransferase-as-predictor-of-risk-for-thiopurine-induced-leukopenia-in-chinese-patients-with-crohn-s-disease
#18
X Zhu, X-D Wang, K Chao, M Zhi, H Zheng, H-L Ruan, S Xin, N Ding, P-J Hu, M Huang, X Gao
BACKGROUND: Thiopurine-induced leukopenia is the most common dangerous adverse event in Asians. NUDT15 R139C was recently proposed to be a promising biomarker for leukopenia with thiopurine therapy in Asians, but this has not been replicated in the Chinese population. AIM: To investigate the influence of NUDT15 R139C, thiopurine S-methyltransferase (TPMT), 6-TGN and 6-MMPR on thiopurine-induced leukopenia in Chinese patients with Crohn's disease. METHODS: Clinical and epidemiological characteristics were reviewed from medical records...
November 2016: Alimentary Pharmacology & Therapeutics
https://www.readbyqxmd.com/read/27603572/advances-and-challenges-in-hereditary-cancer-pharmacogenetics
#19
REVIEW
Ingolf Cascorbi, Anneke Nina Werk
Cancer pharmacogenetics usually considers tumor-specific targets. However, hereditary genetic variants may interfere with the pharmacokinetics of antimetabolites and other anti-cancer drugs, which may lead to severe adverse events. Areas covered: Here, the impact of hereditary genes considered in drug labels such as thiopurine S-methyltransferase (TPMT), UDP-glucuronosyltransferase 1A1 (UTG1A1) and dihydropyrimidine dehydrogenase (DPYD) are discussed with respect to guidelines of the Clinical Pharmacogenetics Implementation Consortium (CPIC)...
January 2017: Expert Opinion on Drug Metabolism & Toxicology
https://www.readbyqxmd.com/read/27577869/nudt15-and-tpmt-genetic-polymorphisms-are-related-to-6-mercaptopurine-intolerance-in-children-treated-for-acute-lymphoblastic-leukemia-at-the-children-s-cancer-center-of-lebanon
#20
Nathalie K Zgheib, Reem Akika, Rami Mahfouz, Carol Al Aridi, Khaled M Ghanem, Raya Saab, Miguel R Abboud, Nidale Tarek, Hassan El Solh, Samar A Muwakkit
BACKGROUND: Interindividual variability in thiopurine-related toxicity could not be completely explained by thiopurine S-methyltransferase (TPMT) polymorphisms, as a number of patients who are homozygous wild type or normal for TPMT still develop toxicity that necessitates 6-mercaptopurine (MP) dose reduction or protocol interruption. Recently, few studies reported on an inherited nucleoside diphosphate-linked moiety X motif 15 (NUDT15) c.415C>T low-function variant that is associated with decreased thiopurine metabolism and leukopenia in childhood acute lymphoblastic leukemia (ALL) and other diseases...
January 2017: Pediatric Blood & Cancer
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