Quantitation of 35S Promoter in Maize DNA Extracts from Genetically Modified Organisms Using Real-Time Polymerase Chain Reaction, Part 2: Interlaboratory Study

The European Committee for Standardization (CEN) and the European Network of GMO Working Laboratories have proposed development of a modular strategy for stepwise validation of complex analytical techniques. When applied to the quantitation of genetically modified organisms (GMOs) in food products, the instrumental quantitation step of the technique is separately validated from the DNA extraction step to better control the sources of uncertainty and facilitate the validation of GMO-specific polymerase chain reaction (PCR) tests. This paper presents the results of an interlaboratory study on the quantitation step of the method standardized by CEN for the detection of a regulatory element commonly inserted in GMO maize-based foods. This is focused on the quantitation of P35S promoter through using the quantitative real-time PCR (QRT-PCR). Fifteen French laboratories participated in the interlaboratory study of the P35S quantitation operating procedure on DNA extract samples using either the thermal cycler ABI Prism® 7700 (Applied Biosystems, Foster City, CA) or Light Cycler® (Roche Diagnostics, Indianapolis, IN). Attention was focused on DNA extract samples used to calibrate the method and unknown extract samples. Data were processed according to the recommendations of ISO 5725 standard. Performance criteria, obtained using the robust algorithm, were compared to the classic data processing after rejection of outliers by the Cochran and Grubbs tests. Two laboratories were detected as outliers by the Grubbs test. The robust precision criteria gave values between the classical values estimated before and after rejection of the outliers. Using the robust method, the relative expanded uncertainty by the quantitation method is about 20% for a 1% Bt176 content, whereas it can reach 40% for a 0.1% Bt176. The performances of the quantitation assay are relevant to the application of the European regulation, which has an accepted tolerance interval of about ±50%. These data were fitted to a power model (r2 = 0.96). Thanks to this model, it is possible to propose an estimation of uncertainty of the QRT-PCR quantitation step and an uncertainty budget depending on the analytical conditions.

P2525Relationship of Charlson Comorbidity Index with adverse events in elderly patients with Acute Coronary Syndromes: an analysis from LONGEVO-SCA Registry

Background

Elderly patients with Acute Coronary Syndromes (ACS) are under-represented in clinical trials and they have higher risk of new due their comorbidities. Charlson Comorbidity Index (CCI) is an established tool for evaluating the burden of comorbidity status and a high score of CCI is related with an increased risk of death.

Purpose

The aim of this study was to analyze the relationship of CCI in adverse outcomes at short-term follow-up in elderly patients admitted by an ACS.

Methods

The prospective multicenter LONGEVO-SCA included unselected elderly patients (≥80 years old) hospitalized after non-STACS. In this substudy, we analyze the influence of comorbidities, comparing the relationship between quartiles of CCI and adverse events at 6 months follow-up of CCI.

Results

We analyzed 520 patients (mean age 84.4±3.6 years; 320 (61.5%) male). 196 (37.6%) were classified into Q1, 105 (20.2%) into Q2, 93 (17.9%) into Q3 and 126 (24.2%) into Q4. No differences were observed in treatment at discharge across different quartiles for aspirin (p=0.648), beta-blockers (p=0.908) or statins (p=0.756). We observed a significant increase for all-cause mortality [9 (4.8%) vs 10 (10.2%) vs 11 (12.0%) vs 32 (26.0%); p<0.001] and readmissions [36 (18.4%) vs 21 (20%) vs 33 (35.5%) vs 48 (38.1%); p<0.001] respectively from Q1 to Q4. After Cox multivariate regression analysis, CCI was independently associated with mortality or readmissions [HR 1.15, 95% CI (1.06–1.26); p=0.001] and patients into high quartile had 6-fold risk of mortality [HR 6.19, 95% CI (2.95–12.99); p<0.001]. Kaplan Meier analysis showed that patients in the highest quartiles had significantly worse prognosis during the follow-up with high risk of all-cause mortality and readmissions (both p<0.001).

Event Free Survival according Charlson

Conclusions

In LONGEVO-SCA registry, we validated for the first time CCI as an independent factor related with adverse events. Patients into high quartiles of CCI had significantly worse prognosis during the follow-up and elderly patients into Q4 had 6-fold risk of mortality compared to Q1 patients.

P2530Frailty assessment in atrial fibrillation patients with acute coronary syndromes: a subanalysis from LONGEVO-SCA registry

Background

Different studies have observed a significant correlation between frailty, morbidity and mortality in elderly patients with cardiovascular diseases.Several scores have been developed to assess frailty in elderly patients. The FRAIL scale is a bed-side and easy tool that evaluates 5 items: fatigue, resistance, ambulation, concomitant diseases and weight loss. However, the evaluation of frailty status in AF patients with ACS is scarce.

Purpose

The aim of this study was to analyze the management of elderly patients with AF and ACS and the predictive value of frailty for adverse events.

Methods

The prospective multicentre LONGEVO-SCA enrolled unselected elderly patients hospitalized after non-STACS. In this substudy, we divided patients according to rhythm status (AF or sinus rhythm [SR]) and to frail status. We validated the predictive performance of FRAIL scores for adverse events at 6 months follow-up.

Results

We analyzed 531 patients (mean age 84.4±3.6 years; 322 (60.6%) male). 128 (24.1%) had AF diagnosis and 145 (27.3%) patients were frail. Frail AF patients had higher risk of global mortality [HR 2.61, (95% CI 1.28–5.31; p=0.008)], readmissions [HR 2.28, (95% CI 1.37–3.80); p=0.002)] and the composite endpoint [HR 2.28, (95% CI 1.44–3.60); p<0.001)] compared with non-frail SR patients. After multivariate adjustment, Frail score [HR 1.41; 95% CI (1.02–1.97); p=0.040] was independently associated with mortality. Kaplan Meier analysis showed that frail AF patients had significantly worse prognosis during the follow-up with high risk of global mortality (log rank p=0.024) and readmission (log rank p<0.001) followed closely by those frail SR patients.

Event Free Survival according Frailty

Conclusions

In the LONGEVO-SCA registry, frail AF patients have 2-fold risk of adverse events compared to non-frail SR patients. Frailty status was an independent condition associated with high risk of adverse events at 6 months of follow-up.

P1752Impact of frailty addition in ischemic and bleeding risk scores in elderly patients with Atrial Fibrillation and Acute Coronary Syndrome: a subanalysis from LONGEVO-SCA registry

Background

The prevalence of Atrial Fibrillation (AF) and Acute Coronary Syndrome (ACS) increases with age. Frail older adults are at high risk of multiple adverse events during admission and short term mortality. FRAIL score is an easy tool that evaluates: fatigue, resistance, ambulation, concomitant diseases and weight loss.

Purpose

The aim of this study was to validate FRAIL score in AF elderly patients with ACS related to adverse events and the impact of its addition in clinical scores.

Methods

The prospective multicenter LONGEVO-SCA enrolled unselected elderly patients hospitalized after non-STACS. We analyzed the predictive performance of FRAIL score in AF subgroup for adverse events (primary endpoint mortality or readmission) and the impact of frailty addition in ischaemic and bleeding scores.

Results

We analyzed 531 patients. 128 (24.1%) of them have AF (main age 84.6±3.7 years; 78 (61%) male) and 27.3% were frail (defined by FRAIL score ≥3). Frail AF patients had more prevalent comorbidities and received less evidence-based ACS therapies at discharge as oral anticoagulation (66% vs 60%; p<0.001) or statins 96.3% vs 82.6%; p<0.001). We analyzed the predictive performance of FRAIL score to adverse events and observed a modest predictive performance for mortality (c-statistic 0.648; 95% CI [0.605–0.690]; p<0.001), readmissions (c-statistic 0.600; 95% CI [0.557–0.642]; p<0.001) and for composite endpoint (c-statistic 0.620; 95% CI [0.577–0.663]; p<0.001). We compared the addition of FRAIL score to the original risk scores and observed a significant improvement for the primary endpoint with the addition to CHA2DS2-Vasc score (p=0.009), GRACE (p<0.001) and CRUSADE scores (p<0.001). (Table)

C-indexes for mortality or readmissions C-index 95% CI p p* Z* CHA2DS2-VASc score 0.619 0.576 to 0.662 <0.001 0.009 2.586 CHA2DS2-VASc score + FRAIL 0.641 0.598 to 0.683 <0.001 HAS-BLED score 0.649 0.606 to 0.691 <0.001 0.445 0.764 HAS-BLED score + FRAIL 0.634 0.590 to 0.675 <0.001 GRACE score 0.599 0.554 to 0.644 0.006 0.001 3.930 GRACE score + FRAIL 0.602 0.556 to 0.646 <0.001 CRUSADE score 0.660 0.613 to 0.705 0.051 0.001 3.287 CRUSADE score + FRAIL 0.664 0.617 to 0.709 <0.001 CI: Confidence interval. *For c-index comparison. p: P value.

Conclusions

This is the first validation of the FRAIL score in AF patients under ACS with a modest predictive performance to adverse events. The addition of frailty to clinical scores improved the predictive performance to adverse events in AF patients.

Dextromethorphan Analgesia in a Human Experimental Model of Hyperalgesia

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

Central pain sensitization is often refractory to drug treatment. Dextromethorphan, an N-methyl-d-aspartate receptor antagonist, is antihyperalgesic in preclinical pain models. The hypothesis is that dextromethorphan is also antihyperalgesic in humans.

Methods

This randomized, double-blind, placebo-controlled, crossover study explores the antihyperalgesic effect of single and repeated 30-mg dose of oral dextromethorphan in 20 volunteers, using the freeze-injury pain model. This model leads to development of primary and secondary hyperalgesia, which develops away from the site of injury and is associated with central sensitization and activation of N-methyl-d-aspartate receptor in the spinal cord. The primary outcome was antihyperalgesia calculated with the area under the curve of the percentage change in mechanical pain threshold (electronic von Frey) on the area of secondary hyperalgesia. The secondary outcomes were mechanical pain threshold on the area of primary hyperalgesia and cognitive (reaction time) effect.

Results

Single 30-mg results are reported. Antihyperalgesia (% · min) is significantly higher on the area of secondary hyperalgesia with dextromethorphan than placebo (median [interquartile range]: 3,029 [746; 6,195] vs. 710 [–3,248; 4,439], P = 0.009, Hedge’s g = 0.8, 95% CI [0.1; 1.4]). On primary hyperalgesia area, mechanical pain threshold 2 h after drug intake is significantly higher with dextromethorphan (P = 0.011, Hedge’s g = 0.63, 95% CI [0.01; 1.25]). No difference in antinociception is observed after thermal painful stimuli on healthy skin between groups. Reaction time (ms) is shorter with placebo than with dextromethorphan (median [interquartile range]: 21.6 [–37.4; 0.1] vs. –1.2 [–24.3; 15.4], P = 0.015, Hedge’s g = 0.75, 95% CI [0.12; 1.39]). Nonserious adverse events occurrence (15%, 3 of 20 volunteers) was similar in both groups.

Conclusions

This study shows that low-dose (30-mg) dextromethorphan is antihyperalgesic in humans on the areas of primary and secondary hyperalgesia and reverses peripheral and central neuronal sensitization. Because dextromethorphan had no intrinsic antinociceptive effect in acute pain on healthy skin, N-methyl-d-aspartate receptor may need to be sensitized by pain for dextromethorphan to be effective.

First Measurement of the Total Neutron Cross Section on Argon between 100 and 800 MeV

We report the first measurement of the neutron cross section on argon in the energy range of 100-800 MeV. The measurement was obtained with a 4.3-h exposure of the Mini-CAPTAIN detector to the WNR/LANSCE beam at LANL. The total cross section is measured from the attenuation coefficient of the neutron flux as it traverses the liquid argon volume. A set of 2631 candidate interactions is divided in bins of the neutron kinetic energy calculated from time-of-flight measurements. These interactions are reconstructed with custom-made algorithms specifically designed for the data in a time projection chamber the size of the Mini-CAPTAIN detector. The energy averaged cross section is 0.91±0.10(stat)±0.09(syst)  b. A comparison of the measured cross section is made to the GEANT4 and FLUKA event generator packages, where the energy averaged cross sections in this range are 0.60 and 0.68 b, respectively.

6th vital sign app: Testing validity and reliability for measuring gait speed

BACKGROUND

Gait speed tests are useful predictors of different health outcomes in people. These tests can be administered by the convenience of one's smartphone.

RESEARCH QUESTION

Is the 6th Vital Sign app valid and reliable for measuring gait speed?

METHODS

The study used a prospective test-retest design. Fifteen college subjects were asked to walk at their normal pace for 2 min. Each subject performed two trials. Speed was recorded by the 6th Vital Sign app, Brower timing gates, and by hand-measurement of distance walked divided by the 2 min. Criterion validity was assessed by paired t-tests, Cohen's D effect sizes, and Pearson correlation tests. Inter-trial reliability within each device was assessed with Pearson correlation tests.

RESULTS

Speed measured by the app was significantly lower than speed measured by gates (p = 0.004) and by hand-measurement (p = 0.009). The difference between gates and hand-measurement was not significant (p = 0.684). The speed measured by gates and hand-measurement were very highly correlated (r = 0.974), but speed measured by app was only moderately correlated with gates (r = 0.370) and hand-measurement (r = 0.365). The inter-trial reliability was fairly high with correlations r = 0.916, 0.944, and 0.941 when speed was measured by the app, gates, and hand-measurement, respectively.

SIGNIFICANCE

The app tended to underestimate speed when compared to gate and hand-measurements. Therefore, we conclude that the 6^th Vital Sign app is not valid for use for clinical diagnosis or prognosis.

FACEHBI: A Prospective Study of Risk Factors, Biomarkers and Cognition in a Cohort of Individuals with Subjective Cognitive Decline. Study Rationale and Research Protocols

BACKGROUND

Long-term longitudinal studies with multimodal biomarkers are needed to delve into the knowledge of preclinical AD. Subjective cognitive decline has been proposed as a risk factor for the development of cognitive impairment. Thus, including individuals with SCD in observational studies may be a cost-effective strategy to increase the prevalence of preclinical AD in the sample.

OBJECTIVES

To describe the rationale, research protocols and baseline characteristics of participants in the Fundació ACE Healthy Brain Initiative (FACEHBI).

DESIGN

FACEHBI is a clinical trial (EudraCT: 2014-000798-38) embedded within a long-term observational study of individuals with SCD.

SETTING

Participants have been recruited at the memory clinic of Fundació ACE (Barcelona) from two different sources: patients referred by a general practitioner and individuals from an Open House Initiative.

PARTICIPANTS

200 individuals diagnosed with SCD with a strictly normal performance in a comprehensive neuropsychological battery.

MEASUREMENTS

Individuals will undergo an extensive neuropsychological protocol, risk factor assessment and a set of multimodal biomarkers including florbetaben PET, structural and functional MRI, diffusion tensor imaging, determination of amyloid species in plasma and neurophthalmologic assessment with optical coherence tomography.

RESULTS

Two hundred individuals have been recruited in 15 months. Mean age was 65.9 years; mean MMSE was 29.2 with a mean of 14.8 years of education.

CONCLUSIONS

FACEHBI is a long-term study of cognition, biomarkers and lifestyle that has been designed upon an innovative symptom-based approach using SCD as target population. It will shed light on the pathophysiology of preclinical AD and the role of SCD as a risk marker for the development of cognitive impairment.