Evaluation of a prenatal screening decision aid: A mixed methods pilot study.

BACKGROUND: We developed a decision aid (DA) to help pregnant women and their partners make informed decisions about prenatal screening for trisomy. We aimed to determine its usefulness for preparing for decision-making and its acceptability among end-users. METHODS: In this mixed-methods pilot study, we recruited participants in three prenatal care settings in Quebec City. Eligible women were over 18 and more than 16 weeks pregnant or had given birth recently. We asked them about the usefulness of the DA using an interview grid based on the Technology Acceptance Model. We performed descriptive statistics and deductive analysis. RESULTS: Thirty-nine dyads or individuals participated in the study. Mean usefulness score was 86.2 ± 13. Most participants found the amount of information in the DA just right (79.5%), balanced (89.7%), and very useful (61.5%). They were less satisfied with the presentation and the values worksheet and suggested different values clarification methods. CONCLUSION: Rigorous pilot tests of DAs with patients are an important stage in their development before the more formal assessments that precede scaling up the DA in clinical practice. PRACTICE IMPLICATIONS: The next version of the DA will integrate the suggestions of end-users for better decision-making processes about prenatal screening for trisomy.

Quantitative DNA methylation analysis of laser capture microdissected formalin-fixed and paraffin-embedded tissues.

We developed an assay to quantify DNA methylation in breast cancer cells isolated by laser capture microdissection (LCM). The assay uses methylation sensitive restriction enzyme (MSRE) digestion and quantitative polymerase chain reaction (qPCR). To assess the validity and precision of the assay, we prepared standard samples with expected methylation percentage (MP) for two gene promoters (PLAU (plasminogen inhibitor, urokinase) and TIMP3 (TIMP metallopeptidase inhibitor 3)) that we compared with measured MPs. We found good linearity of MSRE digestion and qPCR procedures for both promoters (beta=0.90-1.19+/-0.05-0.10 and r=0.95-0.98; all P<0.0001). Moreover, results remained similar after addition of a purification step between MSRE digestion and qPCR procedures. The validity of this technique was also confirmed by successfully replicating previously published MPs of four cell lines for PLAU and TIMP3 promoters. We assessed the consistency of our approach by comparing MPs of PLAU and TIMP3 promoters from nine breast cancer patients and two cell lines using LCM frozen tissues and their corresponding formalin-fixed paraffin-embedded tissues. We found good consistency (intraclass correlation coefficient=0.93) of MPs between frozen tissues and formalin-fixed paraffin-embedded tissues. Our data demonstrate that this assay based on digestion with MSRE and qPCR procedures is a good technique to quantify MP on limited amounts of DNA and may find clinical applications.