Discovery of common and rare genetic risk variants for colorectal cancer.

To further dissect the genetic architecture of colorectal cancer (CRC), we performed whole-genome sequencing of 1,439 cases and 720 controls, imputed discovered sequence variants and Haplotype Reference Consortium panel variants into genome-wide association study data, and tested for association in 34,869 cases and 29,051 controls. Findings were followed up in an additional 23,262 cases and 38,296 controls. We discovered a strongly protective 0.3% frequency variant signal at CHD1. In a combined meta-analysis of 125,478 individuals, we identified 40 new independent signals at P < 5 × 10-8, bringing the number of known independent signals for CRC to ~100. New signals implicate lower-frequency variants, Krüppel-like factors, Hedgehog signaling, Hippo-YAP signaling, long noncoding RNAs and somatic drivers, and support a role for immune function. Heritability analyses suggest that CRC risk is highly polygenic, and larger, more comprehensive studies enabling rare variant analysis will improve understanding of biology underlying this risk and influence personalized screening strategies and drug development.Goncalo R Abecasis has received compensation from 23andMe and Helix. He is currently an employee of Regeneron Pharmaceuticals. Heather Hampel performs collaborative research with Ambry Genetics, InVitae Genetics, and Myriad Genetic Laboratories, Inc., is on the scientific advisory board for InVitae Genetics and Genome Medical, and has stock in Genome Medical. Rachel Pearlman has participated in collaborative funded research with Myriad Genetics Laboratories and Invitae Genetics but has no financial competitive interest

The impact of quality circles on employee work behaviors: a cross-organizational study

The primary goal of this study was to investigate the impact of quality circle (QC) participation on employee work behaviors. Four behavioral outcomes were examined: absenteeism, turnover, productivity, and grievance rates. It was hypothesized that QC participation would have a positive impact on these four variables;A nonequivalent control group design was used to test these hypotheses. Measures of each variable were obtained from organizational records prior to QC implementation and again one year later. Two hundred and fifty members from four Midwestern organizations comprised the treatment group; 221 noncircle employees from the same work groups served as controls;A second goal of the study was a methodological one: to acknowledge the nonindependence of employees within the same work groups. The design, therefore, nested individuals within work groups. Previous studies have failed to consider the issue of nonindependence. The third goal of the study was to utilize a cross-organizational sample, providing the advantage of a larger, more reliable data base and allowing comparisons to be made across organizations;Data analysis was conducted in two phases: Phase 1 treated each organization independently and Phase 2 combined results across organizations. During the first phase, repeated measures analysis of variance was used to analyze all variables for which individual level data were available (absenteeism, performance ratings, grievances). Results of these analyses found no significant (p <.05) effects due to quality circles for the absenteeism variable. Supervisory ratings of work quality were significantly (p <.05) affected by circles, while work quantity ratings were not significantly improved. Significant results were also obtained for the grievances variable;During Phase 2 a chi-square test where x[superscript]2[subscript] 2,k = 2[sigma](-1nP), was used to aggregate the absenteeism results across all four organizations. This test allowed an over-all probability statement, which was significant at p <.05. Overall, the study offered mixed support regarding quality circles' ability to improve employee work behaviors.</p

New directions for teaching and learning

Publ. comme no 132, winter 2012 de la revue New directions for teaching and learningIndexComprend des bibliogr

Measuring aspirin resistance, clopidogrel responsiveness, and postprocedural markers of myonecrosis in patients undergoing percutaneous coronary intervention

Aspirin and clopidogrel are proven to prevent thromboembolic events during percutaneous coronary intervention (PCI). Enzyme release of creatine kinase-MB (CK-MB) enzyme during PCI has been associated with an increased risk of future adverse cardiac events. This study examined the correlation between measurements of aspirin resistance and the level of inhibition of the thienopyridine-specific P2Y12 platelet receptor and CK-MB release after PCI. We prospectively studied 330 patients with elective PCI treated with drug-eluting stents. Patients were pretreated with aspirin and clopidogrel. Patients with positive CK-MB or acute coronary syndrome and those on glycoprotein IIb/IIIa inhibitors were excluded. Serum assays of aspirin resistance (Ultegra Rapid Platelet Function Assay-ASA, Accumetrics) and clopidogrel resistance (Rapid Platelet Function Assay P2Y12, Accumetrics) were performed before PCI. Serum troponinI and CK-MB levels were measured at 8, 16, and 24 hours after PCI. Aspirin resistance unit (ARU) measurement > or =550 was detected in 12 patients (3.7%). Mean platelet reactivity unit (PRU; measurement of inhibition of P2Y12 activity) was 192.2 +/- 95.4 (lower PRU, more inhibition of P2Y12 receptor). There was no correlation between level of ARU or PRU and troponin I or CK-MB release after PCI at any time point. Only multivessel coronary disease was found to be a predictor of any increase in CK-MB in a multivariate analysis (odds ratio 2.2, 95% confidence interval 1.4 to 3.3, p = 0.0003). A positive correlation was found between levels of ARU and PRU. Target vessel revascularization/major adverse cardiac event rate at 6 months was 8.2% with no correlation between ARU or PRU and release of cardiac enzymes or occurrence of adverse cardiac events. In conclusion, this study does not support routine measurements of aspirin and clopidogrel resistance in stable patients undergoing PCI.5 page(s

Outcomes after sirolimus- and paclitaxel-eluting stent implantation in patients with insulin-treated diabetes mellitus

Insulin-treated diabetic patients undergoing drug-eluting stent implantation are prone to high rates of adverse cardiac events. The efficacy of the sirolimus- (SES) and paclitaxel-eluting stent (PES) in this population was analyzed. Registry data for 434 consecutive patients with insulin-treated diabetes who underwent SES or PES implantation were analyzed. The end point, major adverse cardiac events (MACEs) at 1 year, was high for patients with SESs and PESs (20.6% vs 20.2%; p=0.91). Cox regression and propensity analysis were used to compare outcomes. The adjusted hazard ratio (HR) for MACEs according to stent type (Cox model) was 1.0 (95% confidence interval [CI] 0.64 to 1.76, p=0.82). The propensity score-adjusted (C statistic=0.66) HR was 0.95 (95% CI 0.56 to 1.61, p=0.84). Stent thrombosis rates were relatively high at 2.0% for SESs and 1.5% for PESs (p=0.49). The propensity score-adjusted HR for stent thrombosis was 2.7 (95% CI 0.31 to 23.6, p=0.37). In conclusion, SESs and PESs are similarly efficacious in insulin-treated diabetic patients. The high MACE and stent thrombosis rates are of concern. Additional studies in this group of patients are required to determine the optimal mode of revascularization and minimize the overall stent thrombosis rate.6 page(s

Intravascular ultrasound parameters associated with stent thrombosis after drug-eluting stent deployment

Drug-eluting stent (DES) thrombosis (ST) can be devastating. The study aim was to evaluate intravascular ultrasound (IVUS) predictors for DES thrombosis by comparing IVUS studies after implantation in 13 patients with 14 DES thrombosis lesions with a group of controls (30 lesions in 27 patients) matched for history of chronic renal failure and type of DES. Five patients (38%) discontinued dual antiplatelet therapy at the time of ST. There were 3 in-stent restenosis lesions (21%) treated using DESs in the ST group compared with 0 in the control group (p <0.05). Compared with the control group, IVUS studies in the ST group showed a smaller minimum stent area (4.6 +/- 1.1 vs 5.6 +/- 1.7 mm(2), p = 0.0489). In the ST group, 11 of 14 stents had a minimum stent area < or =5.0 mm(2) compared with 12 of 30 in the control group (p = 0.0392). Minimum stent area in patients who stopped clopidogrel therapy and developed ST (5.30 +/- 1.15 mm(2)) tended to be larger compared with that in patients who developed ST while using clopidogrel (4.24 +/- 0.96 mm(2), p = 0.091). Within the 5-mm-long proximal and distal reference segments analyzed, the ST group had larger proximal reference maximum plaque burdens and smaller minimum lumen areas, along with a tendency toward similar findings in the distal reference segments. In conclusion, IVUS findings at the time of DES implantation in patients who subsequently developed ST showed a smaller minimum stent area (especially in patients who developed ST while using clopidogrel) and more residual disease at the stent edges.6 page(s

Drug-eluting stents are associated with similar cardiovascular outcomes when compared to bare metal stents in the setting of acute myocardial infarction

BACKGROUND: Recent randomized trials have demonstrated conflicting results regarding the use of drug-eluting stents (DESs) as compared to bare metal stents (BMSs) in primary percutaneous coronary intervention (PCI). We compared outcomes among patients presenting with acute ST-elevation myocardial infarction (STEMI) who received DES with those who received BMS. METHODS: In-hospital, 30-day, 6-month, and 1-year outcomes of a cohort of 122 patients who underwent primary or facilitated PCI and received a BMS were compared to 122 propensity-matched patients who received a DES. Seventy-two patients received sirolimus-eluting stents, and 50 received paclitaxel-eluting stents. RESULTS: Baseline demographics were similar among groups. One-, 6-, and 12-month outcomes, including reinfarction, death, stent thrombosis, and target vessel revascularization (TVR), were similar among groups. At 1 year, all-cause mortality was 13.3% in the BMS group and 9.2% in the DES group [P=not significant (ns)], recurrent MI was 5.3% in the BMS group vs. 4.4% in the DES group (P=ns), and TVR was 7% in the BMS group vs. 8.7% in the DES group (P=ns). CONCLUSIONS: Our data do not support the general use of DES in the setting of STEMI given similar cardiovascular outcomes among patients receiving BMS or DES, the need for long-term dual antiplatelet therapy with DES, and the possible repercussions of very late stent thrombosis.5 page(s

Drug-eluting stents versus bare metal stents for narrowing in saphenous vein grafts

Conflicting data exist regarding an advantage of drug-eluting stents (DES) over bare metal stents (BMS) in catheter-based treatment of saphenous vein graft (SVG) stenoses. This study was undertaken to compare the efficacy of these modalities in that lesion subset. The DES group consisted of 138 cases with 183 lesions (sirolimus-eluting stents, n = 117; paclitaxel-eluting stents, n = 66) and the BMS group consisted of 344 cases with 478 lesions that were followed to 1 year. We examined a composite end point that comprised death, Q-wave myocardial infarction, and target lesion revascularization. More BMS were deployed per patient (p <0.001) and the diameters of BMS deployed was significantly greater (p <0.001). Peak postprocedure values of creatine kinase-MB (p = 0.003) and troponin I (p = 0.05) were higher in BMS. At 1 year there was no significant superiority of DES over BMS with regard to hard end points (death and Q-wave myocardial infarction). In conclusion, this study indicates that both DES and BMS for SVG disease provide acceptably safe and efficacious results, but unlike the case in native coronary arteries, DES use does not reduce the frequency of the need for repeat revascularization.5 page(s