Phenome-wide association studies on a quantitative trait: application to TPMT enzyme activity and thiopurine therapy in pharmacogenomics.

Phenome-Wide Association Studies (PheWAS) investigate whether genetic polymorphisms associated with a phenotype are also associated with other diagnoses. In this study, we have developed new methods to perform a PheWAS based on ICD-10 codes and biological test results, and to use a quantitative trait as the selection criterion. We tested our approach on thiopurine S-methyltransferase (TPMT) activity in patients treated by thiopurine drugs. We developed 2 aggregation methods for the ICD-10 codes: an ICD-10 hierarchy and a mapping to existing ICD-9-CM based PheWAS codes. Eleven biological test results were also analyzed using discretization algorithms. We applied these methods in patients having a TPMT activity assessment from the clinical data warehouse of a French academic hospital between January 2000 and July 2013. Data after initiation of thiopurine treatment were analyzed and patient groups were compared according to their TPMT activity level. A total of 442 patient records were analyzed representing 10,252 ICD-10 codes and 72,711 biological test results. The results from the ICD-9-CM based PheWAS codes and ICD-10 hierarchy codes were concordant. Cross-validation with the biological test results allowed us to validate the ICD phenotypes. Iron-deficiency anemia and diabetes mellitus were associated with a very high TPMT activity (p = 0.0004 and p = 0.0015, respectively). We describe here an original method to perform PheWAS on a quantitative trait using both ICD-10 diagnosis codes and biological test results to identify associated phenotypes. In the field of pharmacogenomics, PheWAS allow for the identification of new subgroups of patients who require personalized clinical and therapeutic management.

'Open Window': a randomized trial of the effect of new media art using a virtual window on quality of life in patients' experiencing stem cell transplantation.

OBJECTIVES: To measure the psychological effect of an art intervention on hospitalized patients and explore benefits to their quality of life. METHODS: We conducted a large prospective randomized trial between July 2006 and August 2009 of an art intervention, Open Window (OW), in patients undergoing stem cell transplantation for a hematological malignancy compared with a control group. The primary endpoint measured the effect of an art intervention on levels of anxiety, depression, and stress using the Hospital Anxiety and Depression Scale and the Distress Thermometer. The secondary endpoint measured the influence of OW on patients' experiences of stem cell transplantation using the OW survey and expectations questionnaires. RESULTS: Of the 199 patients in the study, 96 were randomized to the intervention group and 103 to the control group. Participants in the intervention group had significantly reduced levels of anxiety on the day before transplant (p = 0.001), at day 7 (p = 0.041), and day 60 (p = 0.035). There was a significant reduction in depression before transplant (p = 0.022). Participants in the intervention group reported better experiences (p < 0.005). Qualitative data showed that those in the intervention group commented freely on their likes and dislikes about OW and how it made them feel. CONCLUSION: An art intervention, OW, had a positive influence on health-related quality of life and patients' experiences of having a stem cell transplant.

Automated determination of serum alpha1-antitrypsin by antitryptic activity measurement.

BACKGROUND: Alpha1-Antitrypsin (A1AT) deficiency is currently detectable by protein immunoassay, phenotyping, and genotyping of the S and Z mutations, but no fully automated method for standard biochemical analyzers is yet available. Here, we present a method that measures the antitryptic activity in serum. This method is rapid, automated, and allows the easy evaluation of a large cohort of patients. METHODS: Our automated assay involves determining serum antitryptic capacity on the Olympus AU 400 autoanalyzer by using trypsin and succinylated gelatin as substrate in the presence of trinitrobenzene sulfonic acid. The results are expressed as a percentage of inhibition of the reaction of trypsin with succinylated gelatin. After we performed analytical validation studies and reference-interval determination based on serum samples from 120 healthy persons, we tested the assay on deidentified samples from 120 patients with various pathologies (primarily pulmonary) of unexplained origin and normal A1AT concentrations and phenotypes. RESULTS: The analysis rate was up to 120 samples per hour. Intraassay CVs ranged from 3.1%-16.2%, and interassay CV was 7.5%. The reference population showed mean (SD) 58.4 (6.7)% inhibition. The detection limit was 9.5% inhibition. The 120 studied patients displayed significantly lower mean activity than 120 healthy individuals (P < 0.0001). CONCLUSION: This assay is stable, reliable, and easily automated by use of open-system analyzers, allowing for the rapid evaluation of patients. After further validation on a larger randomized cohort, this new approach should function as a useful method to explore A1AT deficiency, especially in large-scale studies.

Interindividual variability in TPMT enzyme activity: 10 years of experience with thiopurine pharmacogenetics and therapeutic drug monitoring.

BACKGROUND & AIMS: TPMT activity and metabolite determination (6-thioguanine nucleotides [6-TGN] and 6-methylmercaptopurine nucleotides [6-MMPN]) remain controversial during thiopurine management. This study assessed associations between patient characteristics and TPMT activity, and their impact on metabolite levels. PATIENTS & METHODS: A retrospective review of the laboratory database from a French university hospital identified 7360 patients referred for TPMT phenotype/genotype determination, and/or for 6-TGN/6-MMPN monitoring. RESULTS: Four TPMT phenotypes were identified according to TPMT activity distribution: low, intermediate, normal/high and very high. Based on 6775 assays, 6-TGN concentrations were 1.6-fold higher in TPMT-deficient patients compared with TPMT-normal patients. Azathioprine dose and TPMT genotype were significant predictors of metabolite levels. Furthermore, 6-MMPN and 6-MMPN: 6-TGN ratios were, respectively, 1.6- and 2.2-fold higher in females than in males, despite similar TPMT, 6-TGN and azathioprine doses. An unfavorable ratio (≥20) was associated with a slightly higher TPMT activity. CONCLUSION: These results illustrate the usefulness of pharmacogenomics and metabolite measurement to improve the identification of noncompliance and patients at high risk for toxicity or therapeutic resistance. Original submitted 13 November 2013; Revision submitted 30 January 2014.

[Development of a laboratory test on dried blood spots for facilitating early diagnosis of alpha-1-antitrypsin deficiency]. / Diagnostic biologique du déficit en alpha-1-antitrypsine : développement d'un test simplifié sur goutte de sang recueillie sur papier-filtre.

Alpha- 1-antitrypsin (A1AT) deficiency is a hereditary autosomal codominant genetic disorder resulting in low circulating levels of A1AT and leading to lung and/or liver disease. It remains underdiagnosed and only 5 to 10% of PIZZ patients, the most common form of severe A1AT deficiency, would be actually identified in France. Facilitating early diagnosis of A1AT deficiency would allow a better management of this disease; therefore we have developed and standardized in three laboratories involved in this study, a diagnostic test on dried blood spots (DBS) including quantitative A1AT measurement, phenotyping by IEF electrophoresis and, if necessary, genotyping by SERPINA1 gene sequencing. We performed a quantitative assay on 90 DBS samples by immunoturbidimetric or immunonephelometric methods. We demonstrated that both methods were suitable for this type of sampling and the results obtained were highly correlated (R(2)>0.9) between the three laboratories: for a target value of 1.00 g/L, the results obtained from the three laboratories were between 1.00 and 1.02 g/L. Phenotyping and genotyping were performed under redefined operating conditions and adapted to the analysis of DBS samples. The results were comparable with those obtained for venous blood samples. Following this work, it becomes possible to provide pulmonologists with a reliable kit to perform a capillary blood sampling on filter paper which would allow a large-scale screening of A1AT deficiency in the population particularly affected by this genetic condition.

Validation of an ultra-high performance liquid chromatography tandem mass spectrometric method for quantifying uracil and 5,6-dihydrouracil in human plasma.

A simple, rapid, sensitive and specific ultra-high-performance liquid chromatography-tandem mass spectrometry method (Waters UPLC-MS-MS) is developed and validated for the quantification of uracil (U) and 5,6-dihydrouracil (UH2) levels in human plasma. Analytes are extracted using ethyl acetate and isopropanol after deproteination, and separated by high-performance liquid chromatography (HPLC) (Acquity UPLC BEH C18 column) in a binary mobile phase system under gradient elution conditions at a flow rate of 0.4 mL/min. 5-Bromo-uracil (UBr) is used as the internal standard. The detection is performed on a triple-quadrupole mass spectrometer via electrospray positive ionization. Multiple reaction monitoring mode using the transitions m/z 112.82 → 70.05, m/z 114.88 → 55.04 and m/z 190.83 → 117.86 is used to quantify U, UH2 and UBr, respectively. The method is linear in the concentration range of 0.625-160.0 ng/mL. The total run time is 4.5 min per injection. Nine-point calibration curve and four-points quality controls are used. Excellent linearity and precision are observed with correlation coefficient (r(2)) > 0.9999. The intra-batch and inter-batch precisions are ≤ 7.3% and ≤ 8.6%, and accuracy is ≤ 17%. The developed method is shown to be suitable for routine quantitative determination of U, UH2 and 5,6-dihydrouracil-to-uracil ratio in clinical practice.

À quoi peut servir le Ginseng chez le sportif? / What is the use of Ginseng among sports?

Longtemps précédé d'une flatteuse réputation, mais desservi par la pauvreté des rares arguments expérimentaux semblant confirmr la réalité de ses effets positifs "mythiques", le ginseng fait l'objet d'un récent regain d'intérêt dans le milieu sportif. S'agit-il d'un effet de mode ou d'une avancée réelle? (AU)