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Thiopurine methyltransferase

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https://www.readbyqxmd.com/read/29194039/validation-of-a-high-performance-liquid-chromatography-method-for-thiopurine-s-methyltransferase-activity-in-whole-blood-using-6-mercaptopurine-as-substrate
#1
Hannah Rieger, Patrik Schmidt, Elke Schaeffeler, Manabu Abe, Mira Schiffhauer, Matthias Schwab, Nicolas von Ahsen, Gabriela Zurek, Hartmut Kirchherr, Maria Shipkova, Eberhard Wieland
BACKGROUND: Variation in metabolism, toxicity and therapeutic efficacy of thiopurine drugs is largely influenced by genetic polymorphisms in the thiopurine S-methyltransferase (TPMT) gene. Determination of TPMT activity is routinely performed in patients to adjust drug therapy. METHODS: We further optimized a previously established high-performance liquid chromatography (HPLC) method by measuring TPMT activity in whole blood instead of isolated erythrocytes, which is based on conversion of 6-mercaptopurine to 6-methylmercaptopurine using S-adenosyl-methionine as methyl donor...
December 1, 2017: Clinical Chemistry and Laboratory Medicine: CCLM
https://www.readbyqxmd.com/read/29192347/pharmacogenetics-of-thiopurines-for-inflammatory-bowel-disease-in-east-asia-prospects-for-clinical-application-of-nudt15-genotyping
#2
REVIEW
Yoichi Kakuta, Yoshitaka Kinouchi, Tooru Shimosegawa
The thiopurine drugs 6-mercaptopurine (6-MP) and azathiopurine (AZA) are widely used to treat inflammatory bowel disease. However, the incidence of adverse reactions is high, particularly in Asia, and the mechanisms of toxicity in Asian populations remain unclear. Thiopurine S-methyltransferase (TPMT) is a well-known enzyme that inactivates AZA or 6-MP through methylation and is one of the few pharmacogenetic predictors used in clinical settings in Western countries. Individuals carrying TPMT-deficient genetic variants require reduced drug doses, but this treatment modification is are not applicable to East Asian populations...
November 30, 2017: Journal of Gastroenterology
https://www.readbyqxmd.com/read/29191122/association-between-tpmt-3c-and-decreased-thiopurine-s-methyltransferase-activity-in-patients-with-neuromyelitis-optica-spectrum-disorders-in-china
#3
Xiaoqing Gong, Shenghui Mei, Xindi Li, Xingang Li, Heng Zhou, Yonghong Liu, Anna Zhou, Li Yang, Zhigang Zhao, Xinghu Zhang
AIM OF THE STUDY: Thiopurines are effective drugs in treating neuromyelitis optica spectrum disorders and other diseases. Thiopurines' toxicity is mainly imputed to thiopurine S-methyltransferase activity. In Chinese population, the most common and important variation of thiopurine S-methyltransferase is TPMT*3C (rs1142345). This study aims to reveal the association between thiopurine S-methyltransferase activity and genetic polymorphisms of thiopurine S-methyltransferase in patients with neuromyelitis optica spectrum disorders in China...
December 1, 2017: International Journal of Neuroscience
https://www.readbyqxmd.com/read/29147133/allopurinol-in-combination-with-thiopurine-induces-mucosal-healing-and-improves-clinical-and-metabolic-outcomes-in-ibd
#4
Brigitte Moreau, Pierre Clement, Yves Theoret, Ernest G Seidman
Background: Thiopurines, azathioprine (AZA) and 6-mercaptopurine (6-MP) are common maintenance medications for inflammatory bowel disease (IBD). Excessive methylation via thiopurine methyltransferase (TPMT) frequently causes therapeutic failure. Allopurinol reduces excessive 6-methyl-mercaptopurine (6-MMP) while enhancing 6-thioguanine (6-TGN) levels. The aim of this study was to evaluate clinical, metabolic and endoscopic impact of allopurinol in combination with low-dose thiopurine in IBD...
November 2017: Therapeutic Advances in Gastroenterology
https://www.readbyqxmd.com/read/29065511/novel-tetra-primer-arms-pcr-assays-for-thiopurine-intolerance-susceptibility-mutations-nudt15-c-415c-t-and-tpmt-c-719a-g-tpmt-3c-in-east-asians
#5
Chi-Chun Ho, Wai-Ying Fong, Yuen-Hon Lee, Wing-Tat Poon
Thiopurines are clinically useful in the management of diverse immunological and malignant conditions. Nevertheless, these purine analogues can cause lethal myelosuppression, which may be prevented by prospective testing for variants in the thiopurine S-methyltransferase (TPMT) and, in East Asians, Nudix hydrolase 15 (NUDT15) genes. Two single-tube, tetra-primer amplification refractory mutation system polymerase chain reaction (ARMS-PCR) assays were developed to genotype the common loss-of-function variants NUDT15 c...
October 23, 2017: Genes
https://www.readbyqxmd.com/read/29051993/treatment-related-sinusoidal-obstruction-syndrome-in-children-with-de-novo-acute-lymphoblastic-leukemia-during-intensification
#6
Casey L McAtee, Netta Schneller, Julienne Brackett, M Brooke Bernhardt, Eric S Schafer
PURPOSE: Sinusoidal obstruction syndrome (SOS), also known as veno-occlusive disease, has been described following treatment of acute lymphoblastic leukemia (ALL) with the anti-metabolite 6-thioguanine (6-TG). Previous studies incorporating daily 6-TG into maintenance chemotherapy demonstrated a high incidence of SOS, typically presenting after prolonged exposures to 6-TG. 6-TG continues to be used as a single, 14-day burst during intensification; however, SOS associated with brief courses of 6-TG is poorly described...
October 19, 2017: Cancer Chemotherapy and Pharmacology
https://www.readbyqxmd.com/read/29035443/genetic-variants-of-pre-micrornas-a-499g-rs3746444-and-t-196a2c-rs11614913-with-ulcerative-colitis-uc-and-investigated-with-thiopurine-s-methyltransferase-tpmt-activity
#7
Farideh Ghobadi, Asad Vaisi-Raygani, Fariborz Bahrehmand, Maryam Tanhapour, Amir Kiani, Zohreh Rahimi, Tayebeh Pourmotabbed
BACKGROUND: Abnormal expression and different splicing of miRNAs are involved in several human inflammatory disorders. It has been suggested that gene variants of miRNAs may be associated with increased risk of ulcerative colitis (UC). We aimed to evaluate the association of two SNPs (miRNA-A-499G(rs3746444) and miRNA-T196a2C(rs11614913)) with the risk of UC and monitor their effect on thiopurine-S-methyltransferase (TPMT) activity in Kurdish population of Iran. METHODS: This case-control study was performed on 210 UC patients and 212 healthy individuals...
October 1, 2017: Clinical Laboratory
https://www.readbyqxmd.com/read/28966507/thiopurine-s-methyltransferase-polymorphisms-in-korean-dermatologic-patients
#8
Minseok Lee, Jimyung Seo, Dongsik Bang, Do Young Kim
BACKGROUND: Thiopurine S-methyltransferase (TPMT) is an important enzyme in the metabolism of thiopurines including azathioprine (AZA), 6-mercaptopurine, and 6-thioguanine. TPMT genotyping is widely used for screening of AZA-related toxicity during routine clinical practice in Korea. However, the data of TPMT genotypes and its AZA-related toxicity have not been studied in the field of dermatology. OBJECTIVE: The aim of this study was to evaluate the genetic basis of TPMT polymorphism in Korean dermatologic patients and subsequently to investigate the relationship between mutant TPMT and adverse responses to AZA treatment...
October 2017: Annals of Dermatology
https://www.readbyqxmd.com/read/28950720/biomarkers-of-adverse-drug-reactions
#9
Daniel F Carr, Munir Pirmohamed
Adverse drug reactions can be caused by a wide range of therapeutics. Adverse drug reactions affect many bodily organ systems and vary widely in severity. Milder adverse drug reactions often resolve quickly following withdrawal of the casual drug or sometimes after dose reduction. Some adverse drug reactions are severe and lead to significant organ/tissue injury which can be fatal. Adverse drug reactions also represent a financial burden to both healthcare providers and the pharmaceutical industry. Thus, a number of stakeholders would benefit from development of new, robust biomarkers for the prediction, diagnosis, and prognostication of adverse drug reactions...
January 1, 2017: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28914446/risk-factors-for-thiopurine-induced-myelosuppression-and-infections-in-inflammatory-bowel-disease-patients-with-a-normal-tpmt-genotype
#10
M M T J Broekman, M J H Coenen, G J Wanten, C J van Marrewijk, O H Klungel, A L M Verbeek, P M Hooymans, H-J Guchelaar, H Scheffer, L J J Derijks, D R Wong, D J de Jong
BACKGROUND: Leucopenia is a common side effect in patients treated with thiopurines. Variants in the thiopurine S-methyltransferase (TPMT) gene are the best-known risk factor, but only explain up to 25% of leucopenia cases. AIM: To identify the clinical risk factors for thiopurine-induced leucopenia in patients without a common TPMT variant, and explore if these patients are at increased risk for infections. METHODS: Post hoc analysis of the Thiopurine response Optimisation by Pharmacogenetic testing in Inflammatory bowel disease Clinics (TOPIC) trial...
November 2017: Alimentary Pharmacology & Therapeutics
https://www.readbyqxmd.com/read/28857898/prevalence-of-thiopurine-s-methyltransferase-gene-polymorphisms-in-patients-with-inflammatory-bowel-disease-from-the-island-of-crete-greece
#11
Constantina Coucoutsi, George Emmanouil, George Goulielmos, Ourania Sfakianaki, Ioannis E Koutroubakis, Elias A Kouroumalis
BACKGROUND: There is evidence that genotyping for the thiopurine S-methyltransferase (TPMT) gene variants is useful for the prediction of response to thiopurine analogs (azathioprine and 6-mercaptopurine) in patients with inflammatory bowel disease (IBD). The aim of the present study was to determine the prevalence of TPMT gene polymorphisms in a genetic homogenous population of IBD patients in Crete and to correlate the results with adverse reactions to thiopurine drugs. PATIENTS AND METHODS: Genotyping for the most common TPMT variants TPMT*2, TPMT*3A, TPMT3*C, and TPMT*3B was performed using the PCR-restriction fragment length polymorphism method in 223 consecutive IBD patients and 119 age-matched and sex-matched healthy controls...
November 2017: European Journal of Gastroenterology & Hepatology
https://www.readbyqxmd.com/read/28843236/a-practical-non-extraction-direct-liquid-chromatography-method-for-determination-of-thiopurine-s-methyltransferase-activity-in-inflammatory-bowel-disease
#12
Fariborz Bahrehmand, Amir Kiani, Asad Vaisi-Raygani, Homayoun Bashiri, Mehdi Zobeiri, Ali Moini, Tayebeh Pourmotabbed
Thiopurine drugs remain pivotal therapies for the wide varieties of diseases such as inflammatory bowel disease (IBD). Here, thiopurine S-methyltransferase (TPMT) phenotype, the main metabolizing enzyme of thiopurine-drugs, was studied. This is for the first time that TPMT activity is measured in Iranian IBD patients. We used an improved direct liquid chromatography assay without need for solvent extraction and minimize excess labor handling making it ideal for use in routine referral medical centers. TPMT activity in whole blood was determined by a non-extraction HPLC method...
June 2017: Acta Medica Iranica
https://www.readbyqxmd.com/read/28818801/development-and-validation-of-a-reliable-method-for-thiopurine-methyltransferase-tpmt-enzyme-activity-in-human-whole-blood-by-lc-ms-ms-an-application-for-phenotypic-and-genotypic-correlations
#13
Supaporn Wiwattanakul, Santirhat Prommas, Nuttawut Jenjirattithigarn, Siwalee Santon, Apichaya Puangpetch, Samart Pakakasama, Usanarat Anurathapan, Chonlaphat Sukasem
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of thiopurine methyltransferase (TPMT) activity in human whole blood lysate, based on conversion of 6-mercaptopurine (6-MP) by TPMT to 6-methylmercaptopurine (6-MMP) using S-adenosyl-l-methionine (SAM) as the methyl donor. This method was improved from the previous laborious method for washing of red cell lysate preparation to develop whole blood EDTA lysate. In addition, the TPMT incubation was optimized and the chromatography was performed in a short runtime of 7min on a C18-column by detection via triple quadrupole mass spectrometry...
October 25, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28774547/american-gastroenterological-association-institute-technical-review-on-the-role-of-therapeutic-drug-monitoring-in-the-management-of-inflammatory-bowel-diseases
#14
REVIEW
Niels Vande Casteele, Hans Herfarth, Jeffry Katz, Yngve Falck-Ytter, Siddharth Singh
Therapeutic drug monitoring (TDM), which involves measurement of drug or active metabolite levels and anti-drug antibodies, is a promising strategy that can be used to optimize inflammatory bowel disease therapeutics. It is based on the premise that there is a relationship between drug exposure and outcomes, and that considerable inter-individual variability exists in how patients metabolize the drug (pharmacokinetics) and the magnitude and duration of response to therapy (pharmacodynamics). Therefore, the American Gastroenterological Association has prioritized clinical guidelines on the role of TDM in the management of inflammatory bowel disease...
September 2017: Gastroenterology
https://www.readbyqxmd.com/read/28731668/-azathioprine-induced-pancytopenia-case-series
#15
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-formula-see-text
#16
REVIEW
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...
September 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
#17
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
#18
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...
August 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
#19
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...
September 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
#20
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
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