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Thiopurine methyltransferase

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https://www.readbyqxmd.com/read/28731668/-azathioprine-induced-pancytopenia-case-series
#1
Cristina Martínez Faci, Ignacio Ros Arnal, José M Martínez de Zabarte Fernández, Jordi Sorribes Estorch, Mónica López Campos, Carmen Rodríguez-Vigil Iturrate
Azathioprine is an immunosuppressive drug that has shown effectiveness in inflammatory bowel disease treatment. Its metabolite, 6-mercaptopurine, is metabolized through thiopurine methyltransferase. Patients with low enzyme activity may have more frequent and severe side effects. The most common is leukopenia, and rarely pancytopenia. The thiopurine methyltransferase activity monitoring shows an individualized profile of enzymatic activity but it should not replace monitoring by performing serial blood counts...
August 1, 2017: Archivos Argentinos de Pediatría
https://www.readbyqxmd.com/read/28681659/the-relationship-of-genetics-nursing-practice-and-informatics-tools-in-6-mercaptopurine-dosing-in-pediatric-oncology
#2
Wendy J Haylett
An antileukemic agent prescribed for pediatric oncology patients during the maintenance phase of therapy for acute lymphoblastic leukemia, 6-mercaptopurine (6-MP), is highly influenced by genetic variations in the thiopurine S-methyltransferase enzyme. As such, 6-MP must be dosed so that patients with 1 or 2 inactive thiopurine S-methyltransferase alleles will not incur an increased risk for myelosuppression or other toxicities. Informatics tools such as clinical decision support systems are useful for the application of this and similar pharmacogenetics information to the realm of nursing and clinical practice for safe and effective patient care...
July 1, 2017: Journal of Pediatric Oncology Nursing: Official Journal of the Association of Pediatric Oncology Nurses
https://www.readbyqxmd.com/read/28627831/whole-blood-thiopurine-s-methyltransferase-genotype-and-phenotype-concordance-in-iranian-kurdish-ulcerative-colitis-uc-patients
#3
Fariborz Bahrehmand, Asad Vaisi-Raygani, Amir Kiani, Homayoun Bashiri, Mahdi Zobeiri, Maryam Tanhapour, Tayebeh Pourmotabbed
BACKGROUND: Thiopurine methyl transferase (TPMT), a drug-metabolizing enzyme, catalyzes methylation and consequently, the metabolism of thiopurine compounds used for treatment of inflammatory bowel disease (IBD). Individuals who are homozygous recessive or have extremely low TPMT activity need to avoid thiopurines because of concern for significant leukopenia. The aim of this research was to determine TPMT phenotypes and genotypes in IBD patients to predict the risk of thiopurine toxicity before treatment...
May 1, 2017: Clinical Laboratory
https://www.readbyqxmd.com/read/28623449/differential-effects-of-thiopurine-methyltransferase-tpmt-and-multidrug-resistance-associated-protein-gene-4-mrp4-on-mercaptopurine-toxicity
#4
Chengcheng Liu, Laura J Janke, Jun J Yang, William E Evans, John D Schuetz, Mary V Relling
PURPOSE: Mercaptopurine plays a pivotal role in treatment of acute lymphoblastic leukemia (ALL) and autoimmune diseases, and inter-individual variability in mercaptopurine tolerance can influence treatment outcome. Thiopurine methyltransferase (TPMT) and multi-drug resistant Protein 4 (MRP4) have both been associated with mercaptopurine toxicity in clinical studies, but their relative contributions remain unclear. METHODS: We studied the metabolism of and tolerance to mercaptopurine in murine knockout models of Tpmt, Mrp4, and both genes simultaneously...
June 16, 2017: Cancer Chemotherapy and Pharmacology
https://www.readbyqxmd.com/read/28570428/combined-detection-of-nudt15-variants-could-highly-predict-thiopurine-induced-leukopenia-in-chinese-patients-with-inflammatory-bowel-disease-a-multicenter-analysis
#5
Kang Chao, Xueding Wang, Qian Cao, Jiaming Qian, Kaichun Wu, Xia Zhu, Hong Yang, Jie Liang, Lang Lin, Zicheng Huang, Yu Zhang, Yibiao Huang, Yinghao Sun, Xianmin Xue, Min Huang, Pinjin Hu, Ping Lan, Xiang Gao
BACKGROUND: NUDT15 c.415C>T was a novel genetic marker confirmed in our center for thiopurine-induced leukopenia in Chinese inflammatory bowel disease (IBD). For validation, a large cohort study is needed. Meanwhile, the newly discovered NUDT15 coding variants (c.36_37insGGAGTC and c.52 G>A) have not been studied in patients with IBD. We aimed to further confirm the influence of 3 NUDT15 variants (c.415C>T, c.36_37insGGAGTC, and c.52G>A) on thiopurine-induced leukopenia in Chinese patients with IBD...
May 24, 2017: Inflammatory Bowel Diseases
https://www.readbyqxmd.com/read/28566182/nudt15-p-r139c-variant-is-common-and-strongly-associated-with-azathioprine-induced-early-leukopenia-and-severe-alopecia-in-korean-patients-with-various-neurological-diseases
#6
Sun-Young Kim, Jin-Hong Shin, Jin-Sung Park, Sa-Yoon Kang, Tai-Seung Nam, Jong Kuk Kim, Ki-Jong Park, So-Young Huh, Ji Seon Oh, Boram Kang, Dae-Seong Kim
Azathioprine (AZA)-induced leukopenia is a relatively common complication in Korean patients. In addition to variation in TPMT (thiopurine S-methyltransferase), the NUDT15 p.R139C variant was recently identified to have a strong association with AZA-induced leukopenia. We investigated these associations in Korean patients undergoing AZA treatment with various neurological diseases. Among 84 enrolled patients, 20 (23.8%; 7 early, 13 late) exhibited leukopenia. The NUDT15 p.R139C variant was associated with leukopenia (OR: 11...
July 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28552060/thiopurine-s-methyltransferase-as-a-pharmacogenetic-biomarker-significance-of-testing-and-review-of-major-methods
#7
Chingiz Asadov, Gunay Aliyeva, Kamala Mustafayeva
Thiopurine S-methyltransferase (TPMT) enzyme metabolizes thiopurine drugs which are widely used in various disciplines as well as in leukemias. Individual enzyme activity varies depending on the genetic polymorphisms of TPMT gene located at chromosome 6. Up to 14% of population is known to have a decreased enzyme activity, and if treated with standard doses of thiopurines, these individuals are at the high risk of severe adverse drug reactions (ADR) as myelosuppression, gastrointestinal intolerance, pancreatitis and hypersensitivity...
May 28, 2017: Cardiovascular & Hematological Agents in Medicinal Chemistry
https://www.readbyqxmd.com/read/28525791/determination-of-thiopurine-s-methyltransferase-activity-by-hydrophilic-interaction-liquid-chromatography-hyphenated-with-mass-spectrometry
#8
Daniel Pecher, Svetlana Dokupilová, Zuzana Zelinková, Maikel Peppelenbosch, Veronika Mikušová, Peter Mikuš
Thiopurine S-methyltransferase (TPMT) plays an important role in the metabolism of thiopurines used in the therapy of inflammatory bowel diseases (IBD). In this work a new progressive method for the determination of TPMT activity in red blood cells lysates was developed. Analysis was carried out by means of hydrophilic interaction liquid chromatography (HILIC) hyphenated with mass spectrometry (MS). In comparison with reversed-phase high-performance liquid chromatography (RP-HPLC), that has been typically applied in determination of TPMT activity, the HILIC significantly improved the analytical signal provided by MS, shortened analysis time, and improved chromatographic resolution...
May 10, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28523321/autoimmune-hepatitis-with-sclerosing-cholangitis-in-a-patient-with-thiopurine-methyltransferase-deficiency-case-presentation
#9
Sorin Claudiu Man, Cristina Nicoleta Schnell, Valentina Sas, Anca Dana Buzoianu, Dan Gheban
The association between two autoimmune diseases is known in the literature as overlap syndrome. We present the case of an 18-year-old boy, diagnosed at the age of 13 with an overlap syndrome between type I autoimmune hepatitis and sclerosing cholangitis. The response to immunosuppressant therapy was hampered by azathioprine-induced toxicity causing severe pancytopenia, as a result of thiopurine methyltransferase enzyme genetic deficiency. Treatment was replaced by mycophenolate mofetil. Although the relapse rate was reduced, the disease progressed to cirrhosis...
2017: Romanian Journal of Morphology and Embryology, Revue Roumaine de Morphologie et Embryologie
https://www.readbyqxmd.com/read/28507448/thiopurine-s-methyltransferase-polymorphisms-in-acute-lymphoblastic-leukemia-inflammatory-bowel-disease-and-autoimmune-disorders-influence-on-treatment-response
#10
REVIEW
Rachid Abaji, Maja Krajinovic
The thiopurine S-methyltransferase (TPMT) gene encodes for the TPMT enzyme that plays a crucial role in the metabolism of thiopurine drugs. Genetic polymorphisms in this gene can affect the activity of the TPMT enzyme and have been correlated with variability in response to treatment with thiopurines. Advances in the pharmacogenetics of TPMT allowed the development of dosing recommendations and treatment strategies to optimize and individualize prescribing thiopurine in an attempt to enhance treatment efficacy while minimizing toxicity...
2017: Pharmacogenomics and Personalized Medicine
https://www.readbyqxmd.com/read/28500740/children-with-low-risk-acute-lymphoblastic-leukemia-are-at-highest-risk-of-second-cancers
#11
Stine N Nielsen, Frank Eriksson, Susanne Rosthoej, Mette K Andersen, Erik Forestier, Henrik Hasle, Lisa L Hjalgrim, Ann Aasberg, Jonas Abrahamsson, Mats Heyman, Ólafur G Jónsson, Kaie Pruunsild, Goda E Vaitkeviciené, Kim Vettenranta, Kjeld Schmiegelow
BACKGROUND: The improved survival rates for childhood acute lymphoblastic leukemia (ALL) may be jeopardized by the development of a second cancer, which has been associated with thiopurine therapy. PROCEDURE: We retrospectively analyzed three sequential Nordic Society of Paediatric Haematology and Oncology's protocols characterized by increasing intensity of thiopurine-based maintenance therapy. We explored the risk of second cancer in relation to protocols, risk group, thiopurine methyltransferase (TPMT) activity, ALL high hyperdiploidy (HeH), and t(12;21)[ETV6/RUNX1]...
May 13, 2017: Pediatric Blood & Cancer
https://www.readbyqxmd.com/read/28498350/comparison-of-direct-sequencing-real-time-pcr-high-resolution-melt-pcr-hrm-and-pcr-restriction-fragment-length-polymorphism-pcr-rflp-analysis-for-genotyping-of-common-thiopurine-intolerant-variant-alleles-nudt15-c-415c-t-and-tpmt-c-719a-g-tpmt-3c
#12
Wai-Ying Fong, Chi-Chun Ho, Wing-Tat Poon
Thiopurine intolerance and treatment-related toxicity, such as fatal myelosuppression, is related to non-function genetic variants encoding thiopurine S-methyltransferase (TPMT) and Nudix hydrolase 15 (NUDT15). Genetic testing of the common variants NUDT15:NM_018283.2:c.415C>T (Arg139Cys, dbSNP rs116855232 T allele) and TPMT: NM_000367.4:c.719A>G (TPMT*3C, dbSNP rs1142345 G allele) in East Asians including Chinese can potentially prevent treatment-related complications. Two complementary genotyping approaches, real-time PCR-high resolution melt (PCR-HRM) and PCR-restriction fragment length morphism (PCR-RFLP) analysis were evaluated using conventional PCR and Sanger sequencing genotyping as the gold standard...
May 12, 2017: Diagnostics
https://www.readbyqxmd.com/read/28476189/analysis-of-thiopurine-s-methyltransferase-deficient-alleles-in-acute-lymphoblastic-leukemia-patients-in-mexican-patients
#13
Silvia Jiménez-Morales, Mireya Ramírez-Florencio, Juan Manuel Mejía-Aranguré, Juan Carlos Núñez-Enríquez, Carolina Bekker-Mendez, José Luis Torres-Escalante, Janet Flores-Lujano, Elva Jiménez-Hernández, María Del Carmen Rodríguez-Zepeda, Yelda A Leal, Pablo Miguel González-Montalvo, Francisco Pantoja-Guillen, José Gabriel Peñaloza-Gonzalez, Erick Israel Gutiérrez-Juárez, Nora Nancy Núñez-Villegas, Maria Luisa Pérez-Saldivar, Francisco Xavier Guerra-Castillo, Luz Victoria Flores-Villegas, María Teresa Ramos-Cervantes, José Manuel Fragoso, María Guadalupe García-Escalante, Doris Del Carmen Pinto-Escalante, Julián Ramírez-Bello, Alfredo Hidalgo-Miranda
BACKGROUND AND AIMS: It has been demonstrated that heterozygote and homozygote thiopurine S-methyltransferase (TPMT) mutant allele carriers are at high risk to develop severe and potentially fatal hematopoietic toxicity after treatment with standard doses of 6-mercaptopurine (6-MP) and methotrexate (MX). Those drugs are the backbone of acute lymphoblastic leukemia (ALL) and several autoimmune disease treatments. We undertook this study to determine the frequency of the TPMT deficient alleles in children with ALL and non-ALL subjects from Mexico City and Yucatan, Mexico...
November 2016: Archives of Medical Research
https://www.readbyqxmd.com/read/28462921/one-amino-acid-makes-a-difference-characterization-of-a-new-tpmt-allele-and-the-influence-of-sam-on-tpmt-stability
#14
Yan Ping Heidi Iu, Sara Helander, Anna Zimdahl Kahlin, Chun Wah Cheng, Chi Chung Shek, Moon Ho Leung, Björn Wallner, Lars-Göran Mårtensson, Malin Lindqvist Appell
Thiopurine induced toxicity is associated with defects in the thiopurine methyltransferase (TPMT) gene. TPMT is a polymorphic enzyme, with most of the single nucleotide polymorphisms (SNPs) causing an amino acid change, altering the enzymatic activity of the TPMT protein. In this study, we characterize a novel patient allele c.719A > C, named TPMT*41, together with the more common variant *3C c.719A > G, resulting in an amino acid shift at tyrosine 240 to serine, p.Y240S and cysteine, p.Y240C respectively...
May 2, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28445188/tpmt-comt-and-acyp2-genetic-variants-in-paediatric-cancer-patients-with-cisplatin-induced-ototoxicity
#15
Signe Thiesen, Peng Yin, Andrea L Jorgensen, Jieying Eunice Zhang, Valentina Manzo, Laurence McEvoy, Christopher Barton, Susan Picton, Simon Bailey, Penelope Brock, Harish Vyas, David Walker, Guy Makin, Srinivas Bandi, Barry Pizer, Daniel B Hawcutt, Munir Pirmohamed
OBJECTIVES: Cisplatin ototoxicity affects 42-88% of treated children. Catechol-O-methyltransferase (COMT), thiopurine methyltransferase (TPMT) and AYCP2 genetic variants have been associated with ototoxicity, but the findings have been contradictory. The aims of the study were as follows: (a) to investigate these associations in a carefully phenotyped cohort of UK children and (b) to perform a systematic review and meta-analysis. METHODS: We recruited 149 children from seven UK centres using a retrospective cohort study design...
June 2017: Pharmacogenetics and Genomics
https://www.readbyqxmd.com/read/28406961/pharmacogenetic-variants-in-tpmt-alter-cellular-responses-to-cisplatin-in-inner-ear-cell-lines
#16
Amit P Bhavsar, Erandika P Gunaretnam, Yuling Li, Jafar S Hasbullah, Bruce C Carleton, Colin J D Ross
Cisplatin is a highly-effective and widely-used chemotherapeutic agent that causes ototoxicity in many patients. Pharmacogenomic studies of key genes controlling drug biotransformation identified variants in thiopurine methyltransferase (TPMT) as predictors of cisplatin-induced ototoxicity, although the mechanistic basis of this interaction has not been reported. Expression constructs of TPMT*3A, *3B and *3C variants were generated and monitored in cultured cells. Cellular TPMT*3A levels were detected at >20-fold lower amounts than the wild type confirming the unstable nature of this variant...
2017: PloS One
https://www.readbyqxmd.com/read/28404197/mercaptopurine-versus-placebo-to-prevent-recurrence-of-crohn-s-disease-after-surgical-resection-toppic-a-multicentre-double-blind-randomised-controlled-trial
#17
Craig Mowat, Ian Arnott, Aiden Cahill, Malcolm Smith, Tariq Ahmad, Sreedhar Subramanian, Simon Travis, John Morris, John Hamlin, Anjan Dhar, Chuka Nwokolo, Cathryn Edwards, Tom Creed, Stuart Bloom, Mohamed Yousif, Linzi Thomas, Simon Campbell, Stephen J Lewis, Shaji Sebastian, Sandip Sen, Simon Lal, Chris Hawkey, Charles Murray, Fraser Cummings, Jason Goh, James O Lindsay, Naila Arebi, Lindsay Potts, Aileen J McKinley, John M Thomson, John A Todd, Mhairi Collie, Malcolm G Dunlop, Ashley Mowat, Daniel R Gaya, Jack Winter, Graham D Naismith, Holly Ennis, Catriona Keerie, Steff Lewis, Robin J Prescott, Nicholas A Kennedy, Jack Satsangi
BACKGROUND: Up to 60% of patients with Crohn's disease need intestinal resection within the first 10 years of diagnosis, and postoperative recurrence is common. We investigated whether mercaptopurine can prevent or delay postoperative clinical recurrence of Crohn's disease. METHODS: We did a randomised, placebo-controlled, double-blind trial at 29 UK secondary and tertiary hospitals of patients (aged >16 years in Scotland or >18 years in England and Wales) who had a confirmed diagnosis of Crohn's disease and had undergone intestinal resection...
December 2016: Lancet. Gastroenterology & Hepatology
https://www.readbyqxmd.com/read/28391009/the-promise-of-pharmacogenomics-in-reducing-toxicity-during-acute-lymphoblastic-leukemia-maintenance-treatment
#18
REVIEW
Shoshana Rudin, Marcus Marable, R Stephanie Huang
Pediatric acute lymphoblastic leukemia (ALL) affects a substantial number of children every year and requires a long and rigorous course of chemotherapy treatments in three stages, with the longest phase, the maintenance phase, lasting 2-3years. While the primary drugs used in the maintenance phase, 6-mercaptopurine (6-MP) and methotrexate (MTX), are necessary for decreasing risk of relapse, they also have potentially serious toxicities, including myelosuppression, which may be life-threatening, and gastrointestinal toxicity...
April 2017: Genomics, Proteomics & Bioinformatics
https://www.readbyqxmd.com/read/28374975/enrichment-of-genetic-variants-in-the-glucocorticoid-receptor-signalling-pathway-in-autoimmune-hepatitis-with-failure-of-standard-treatment
#19
Peter Lykke Eriksen, Martin Kreutzfeldt, Henning Grønbaek, Kasper Thorsen, Søren Vang, Niels Jessen, Hendrik Vilstrup
The standard treatment for autoimmune hepatitis (AIH) is predniso(lo)ne for remission induction, tapered and followed by azathioprine, which effectively controls the disease in the majority of patients. However, some patients prove to be unresponsive or non-tolerant and require alternative immunosuppressive regimens for disease control. We aimed to investigate whether these AIH patients who experience failure of standard treatment have a genomic basis for their problem in the form of pharmacogenetic variants...
April 4, 2017: Basic & Clinical Pharmacology & Toxicology
https://www.readbyqxmd.com/read/28296824/multicentric-case-control-study-on-azathioprine-dose-and-pharmacokinetics-in-early-onset-pediatric-inflammatory-bowel-disease
#20
Gabriele Stocco, Stefano Martelossi, Serena Arrigo, Arrigo Barabino, Marina Aloi, Massimo Martinelli, Erasmo Miele, Daniela Knafelz, Claudio Romano, Samuele Naviglio, Diego Favretto, Eva Cuzzoni, Raffaella Franca, Giuliana Decorti, Alessandro Ventura
BACKGROUND: Early-onset inflammatory bowel disease (IBD) is generally aggressive, with a high probability of complications and need of surgery. Despite the introduction of highly effective biological drugs, treatment with azathioprine continues to be important even for early-onset IBD; however, in these patients azathioprine response seems to be reduced. This study evaluated azathioprine doses, metabolite concentrations, and their associations with patients' age in children with IBD treated at 6 tertiary pediatric referral centers...
April 2017: Inflammatory Bowel Diseases
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