Carmen Lindsay

Implication of an AGT haplotype in a multigene association study with pregnancy hypertension.

Abstract—Several association studies of candidate genes for preeclampsia and essential hypertension have led to discordant results, partly because of small sample sizes. Using a large population-based sample of pregnant women, we conducted an association study of 10 polymorphisms in 9 genes and aimed (1) to validate 10 published associations with preeclampsia or essential hypertension, (2) to investigate candidate polymorphisms previously associated with preeclampsia for association with essential hypertension and similarly with polymorphisms previously associated with essential hypertension. From a prospective sample of 3391 nulliparous French Canadian pregnant women, we identified 180 cases of preeclampsia, 203 cases of essential hypertension that were matched with normotensive control subjects (n=310 and 357, respectively). Polymorphisms were genotyped by allele-specific PCR. Among our candidate polymorphisms, the Met allele of Thr174Met of AGT was associated with preeclampsia (P =0.0033). Haplotype analysis revealed that the A-Met-Thr (G1035A-Thr174Met-Met235Thr) haplotype was associated with a 2.1-fold increased risk of preeclampsia (95% CI, 1.4 to 3.4; P =0.0008). In conclusion, we observed a strong association between a specific AGT haplotype and preeclampsia in our population, without replicating previous published associations with either preeclampsia or essential hypertension. Our data support a role for AGT in genetic susceptibility to preeclampsia.

Risk of Misdiagnosis Due to Allele Dropout and False-Positive PCR Artifacts in Molecular Diagnostics: Analysis of 30,769 Genotypes

Quality control is a complex issue for clinical molecular diagnostic applications. In the case of genotyping assays, artifacts such as allele dropout represent a risk of misdiagnosis for amplification-based methods. However, its frequency of occurrence in PCR-based diagnostic assays remains unknown. To maximize the likelihood of detecting allele dropout, our clinical genotyping PCR-based assays are designed with two independent assays for each allele (nonoverlapping primers on each DNA strand). To estimate the incidence of allelic dropout, we took advantage of the capacity of our clinical assays to detect such events. We retrospectively studied their occurrence in the initial PCR assay for 30,769 patient reports for mutations involved in four diseases produced over 8 years. Ninety-three allele dropout events were detected and all were solved before reporting. In addition, 42 cases of artifacts caused by amplification of an allele ultimately confirmed to not be part of the genotype (drop-in events) were detected and solved. These artifacts affected 1:227 genotypes, 94% of which were due to nonreproducible PCR failures rather than sequence variants interfering with the assay, suggesting that careful primer design cannot prevent most of these errors. This provides a quantitative estimate for clinical laboratories to take this phenomenon into account in quality management and to favor assay designs that can detect (and minimize) occurrence of these artifacts in routine clinical use.

An economic evaluation: Simulation of the cost-effectiveness and cost-utility of universal prevention strategies against osteoporosis-related fractures

A patient‐level Markov decision model was used to simulate a virtual cohort of 500,000 women 40 years old and over, in relation to osteoporosis‐related hip, clinical vertebral, and wrist bone fractures events. Sixteen different screening options of three main scenario groups were compared: (1) the status quo (no specific national prevention program); (2) a universal primary prevention program; and (3) a universal screening and treatment program based on the 10‐year absolute risk of fracture. The outcomes measured were total directs costs from the perspective of the public health care system, number of fractures, and quality‐adjusted life‐years (QALYs). Results show that an option consisting of a program promoting physical activity and treatment if a fracture occurs is the most cost‐effective (CE) (cost/fracture averted) alternative and also the only cost saving one, especially for women 40 to 64 years old. In women who are 65 years and over, bone mineral density (BMD)‐based screening and treatment based on the 10‐year absolute fracture risk calculated using a Canadian Association of Radiologists and Osteoporosis Canada (CAROC) tool is the best next alternative. In terms of cost‐utility (CU), results were similar. For women less than 65 years old, a program promoting physical activity emerged as cost‐saving but BMD‐based screening with pharmacological treatment also emerged as an interesting alternative. In conclusion, a program promoting physical activity is the most CE and CU option for women 40 to 64 years old. BMD screening and pharmacological treatment might be considered a reasonable alternative for women 65 years old and over because at a healthcare capacity of

Effects of smoking cessation on maternal airway function and birth weight

50,000 Canadian dollars (

Do prostacyclin and thromboxane contribute to the “protective effect” of pregnancies with chronic hypertension? A preliminary prospective longitudinal study

CAD) for each additional fracture averted or for one QALY gained its probabilities of cost‐effectiveness compared to the program promoting physical activity are 63% and 75%, respectively, which could be considered socially acceptable. Consideration of the indirect costs could change these findings.

Development and description of GETT: a Genetic testing Evidence Tracking Tool

Objective To evaluate the effects of smoking cessation before or early in pregnancy on maternal airway function and birth weight. Methods Measurements of forced expiratory spirometry including forced vital capacity, forced expiratory volume in 1 second, forced expiratory flow rates between 0.2 and 1.2 L, 25% and 75%, and 75% and 85%, and instantaneous flows at lung volumes of 25%, 50%, and 75% were carried out by a wedge bellow spirometer in 40 pregnant exsmokers and were compared with those of 175 nonsmoking and 97 currently smoking pregnant women. Spirometric testing was conducted at a mean (± SD) gestational age of 21.5 ± 7.0 weeks. In exsmokers, the average lifetime cigarette consumption was 17.1 ± 8.1/day for a mean duration of 9.7 ± 3.9 years, similar to that observed in current smokers. The median duration of smoking abstinence was 20 weeks before study spirometry. Results All spirometric measurements in exsmokers were similar to those of nonsmokers and were significantly higher than those of current smokers. Spirometric measurements for nonsmokers, current smokers, and exsmokers were respectively: forced expiratory volume in 1 second (3.36 ± 0.39, 3.09 ± 0.45, and 3.35 ± 0.32 L); forced expiratory flow rate between 25% and 75% (ie, mid-expiratory phase) (3.85 ± 0.69, 3.21 ± 0.76, and 3.86 ± 0.66 L/sec); forced expiratory flow rate between 75% and 85% (ie end-expiratory phase) (1.39 ± 0.35, 1.03 ± 0.35, and 1.41 ± 0.39 L/sec); instantaneous flow at lung volume of 50% (4.35 ± 0.82, 3.76 ± 0.89 and 4.36 ± 0.68 L/sec); and instantaneous flow at lung volume of 25% (1.91 ± 0.47, 1.47 ± 0.49, and 1.92 ± 0.46 L/sec). Mean gestational age at delivery was similar among the three groups (277 ± 11, 274 ± 12, and 274 ± 11 days for nonsmokers, current smokers, and exsmokers, respectively). The mean birth weight of babies born to exsmokers (3408 ± 511 g) was similar to that of babies born to nonsmokers (3469 ± 461 g), but was significantly greater than that of babies born to smoking pregnant women (3189 ± 485 g; P < .001) Conclusion Smoking cessation either before or at an early stage of pregnancy is associated with early, reversible increments of maternal airway function and mean birth weights that are higher than among women who continue smoking.

Development of an enzyme-linked immunosorbent assay for 2,3-dinor-6-keto-prostagland in F1α in urine using a monoclonal antibody

OBJECTIVE The aim of this study was to assess prospectively the urinary excretion of renal and systemic metabolites of thromboxane and prostacyclin in normotensive and chronic hypertensive pregnancies. STUDY DESIGN Pregnant hospital employees were invited to collect 24-hour urine samples weekly from the seventh week until delivery. Concentrations of renal metabolites (thromboxane B2, 6-keto-prostaglandin F1alpha) were measured by radioimmunoassay after extraction. Systemic metabolites (2,3-dinor-thromboxane B2, 2,3-dinor-6-keto-prostaglandin F1alpha) were assessed by enzyme immunoassay after extraction and high-pressure liquid chromatographic separation. RESULTS Thromboxane B2 excretion was similar in normotensive and hypertensive pregnancies, whereas a twofold increase of 6-keto-prostaglandin F1alpha was observed in hypertensive compared with normotensive pregnancies (7537 +/- 349 vs 3857 +/- 202 pg/mg creatinine, p < 0.001). During pregnancy in both conditions measurements displayed uniform excretion of thromboxane B2 with progressively increased levels of 6-keto-prostaglandin F1alpha in chronic hypertension (R2 = 0.60, p < 0.005). Mean excretion of 2,3-dinor-thromboxane B2 averaged 1208 +/- 65 and 898 +/- 48 pg/mg creatinine in normotensive and hypertensive pregnancies (p < 0.001), mainly due to significant decreased concentrations in hypertension in the first half of pregnancy. Conversely, 2,3-dinor-6-keto-prostaglandin F1alpha levels were 845 +/- 39 and 1226 +/- 67 pg/mg creatinine in normotensive and hypertensive pregnancies (p < 0.001), mostly because of significantly increased production in hypertension from 22 weeks onward. Ratios of both renal and systemic metabolites favored increased prostacyclin production in chronic hypertension. CONCLUSION In contrast to preeclampsia, uncomplicated mild to moderate chronic hypertensive pregnancies are characterized by an excess production of prostacyclin with unaltered or even lower thromboxane concentrations, which may contribute to the general favorable outcome of this hypertensive condition.

The Fragile X Mental Retardation Syndrome 20 Years After the FMR1 Gene Discovery: an Expanding Universe of Knowledge

Abstract Background: The completion of the Human Genome Project has increased the pace of discovery of genetic markers for disease. Despite tremendous efforts in fundamental research, clinical applications still lag behind expectations, partly due to the lack of effective tools to systematically search for and summarize published data relative to the clinical assessment of new diagnostic molecular tests. Methods: Through a collaborative process using published tools and an expert panel, we developed a detailed checklist of the evidence that needs to be collected or produced to evaluate the potential usefulness of a new molecular diagnostic test. This tool is called GETT, for Genetic testing Evidence Tracking Tool. Results: GETT allows 1) researchers to summarize the current evidence and to identify knowledge gaps for further research and; 2) stakeholders to collect data related to a given molecular test and improve their decision-making process. GETT comprises 72 clearly defined items/questions, grouped into 10 categories and 26 sub-themes, including an overview of disease epidemiology and genetics, the available diagnostic tools, and their analytical and clinical performances, availability of quality control programs, laboratory and clinical best practice guidelines, clinical utility, and impact on health care and psycho-social, ethical and legal implications. It also includes a summary of the evidence available and attempts to prioritise knowledge gaps related to the testing. We also compare GETT to other existing frameworks. Conclusions: This systematic evidence-based tracking tool, which is more detailed than existing frameworks and provides clear definition for each item, will help streamline collection of the available evidence to appraise the potential for clinical application of new molecular diagnostic tests and prioritize research to produce the evidence-base relative to the clinical implementation of molecular diagnostic tests. Clin Chem Lab Med 2010;48:1397–407.

Dabigatran versus warfarin under standard or pharmacogenetic-guided management for the prevention of stroke and systemic thromboembolism in patients with atrial fibrillation: a cost/utility analysis using an analytic decision model

Objectives: To develop and validate an enzyme-linked immunosorbent assay (ELISA) for measurement of urinary 2,3-dinor-6-keto-prostaglandin F1α (2,3D6KPGF1α) using a monoclonal antibody and a horseradish peroxidase-linked antigen. Design and Methods: Assay validation included optimization of the standard curve, antibody cross-reactivity, accuracy and imprecision studies together with preliminary measurement of clinical samples. Results: Optimal conditions of the standard curve (0.078–10.0 μg/L) used 2 mg/L of antibody, and 3 μg/L of peroxidase conjugate in each well, at pH 7.2. The coefficient of variation of various concentrations of the standard curve averaged 6.8%. Antibody cross-reactivity was <0.01% for related prostanoids. Recovery of known amounts (0.1–5.0 μg/L) of 2,3D6KPGF1α added to an urinary sample was 101.2 ± 6.3%. Imprecision studies with non-pregnant (0.24 μg/L) and pregnant (2.5 μg/L) samples displayed an intraassay variability of 8.9 and 9.9%, and an interassay variability of 9.6 and 10.0%, respectively. Urinary measurements in the non-pregnant and pregnant states were similar to those previously reported. An apparent decreased concentration was observed early in pregnancy in future preeclampsia. Conclusion: With similar precision and validity, our assay method is time- and cost-saving. Preliminary urinary measurements show that this analyte may be of interest as an early marker for preeclampsia.