Fitness to drive and cannabis: Validation of two blood THCCOOH thresholds to distinguish occasional users from heavy smokers.

Many studies based on either an experimental or an epidemiological approach, have shown that the ability to drive is impaired when the driver is under the influence of cannabis. Baseline performances of heavy users remain impaired even after several weeks of abstinence. Symptoms of cannabis abuse and dependence are generally considered incompatible with safe driving. Recently, it has been shown that traffic safety can be increased by reporting the long-term unfit drivers to the driver licensing authorities and referring the cases for further medical assessment. Evaluation of the frequency of cannabis use is a prerequisite for a reliable medical assessment of the fitness to drive. In a previous paper we advocated the use of two thresholds based on 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) concentration in whole blood to help to distinguish occasional cannabis users (≤3μg/L) from heavy regular smokers (≥40μg/L). These criteria were established on the basis of results obtained in a controlled cannabis smoking study with placebo, carried out with two groups of young male volunteers; the first group was characterized by a heavy use (≥10 joints/month) while the second group was made up of occasional users smoking at most 1 joint/week. However, to date, these cutoffs have not been adequately assessed under real conditions. Their validity can now be evaluated and confirmed with 146 traffic offenders' real cases in which the whole blood cannabinoid concentrations and the frequency of cannabis use are known. The two thresholds were not challenged by the presence of ethanol (40% of cases) and of other therapeutic and illegal drugs (24%). Thus, we propose the following procedure that can be very useful in the Swiss context but also in other countries with similar traffic policies: if the whole blood THCCOOH concentration is higher than 40μg/L, traffic offenders must be directed first and foremost toward medical assessment of their fitness to drive. This evaluation is not recommended if the THCCOOH concentration is lower than 3μg/L and if the self-rated frequency of cannabis use is less than 1 time/week. A THCCOOH level between these two thresholds cannot be reliably interpreted. In such a case, further medical assessment and follow-up of the fitness to drive are also suggested, but with lower priority.

Experimental and computational approaches to quantitative proteomics: status quo and outlook.

Proteomics has come a long way from the initial qualitative analysis of proteins present in a given sample at a given time ("cataloguing") to large-scale characterization of proteomes, their interactions and dynamic behavior. Originally enabled by breakthroughs in protein separation and visualization (by two-dimensional gels) and protein identification (by mass spectrometry), the discipline now encompasses a large body of protein and peptide separation, labeling, detection and sequencing tools supported by computational data processing. The decisive mass spectrometric developments and most recent instrumentation news are briefly mentioned accompanied by a short review of gel and chromatographic techniques for protein/peptide separation, depletion and enrichment. Special emphasis is placed on quantification techniques: gel-based, and label-free techniques are briefly discussed whereas stable-isotope coding and internal peptide standards are extensively reviewed. Another special chapter is dedicated to software and computing tools for proteomic data processing and validation. A short assessment of the status quo and recommendations for future developments round up this journey through quantitative proteomics.

Strong time dependence of the 76-gene prognostic signature for node-negative breast cancer patients in the TRANSBIG multicenter independent validation series.

PURPOSE: Recently, a 76-gene prognostic signature able to predict distant metastases in lymph node-negative (N(-)) breast cancer patients was reported. The aims of this study conducted by TRANSBIG were to independently validate these results and to compare the outcome with clinical risk assessment. EXPERIMENTAL DESIGN: Gene expression profiling of frozen samples from 198 N(-) systemically untreated patients was done at the Bordet Institute, blinded to clinical data and independent of Veridex. Genomic risk was defined by Veridex, blinded to clinical data. Survival analyses, done by an independent statistician, were done with the genomic risk and adjusted for the clinical risk, defined by Adjuvant! Online. RESULTS: The actual 5- and 10-year time to distant metastasis were 98% (88-100%) and 94% (83-98%), respectively, for the good profile group and 76% (68-82%) and 73% (65-79%), respectively, for the poor profile group. The actual 5- and 10-year overall survival were 98% (88-100%) and 87% (73-94%), respectively, for the good profile group and 84% (77-89%) and 72% (63-78%), respectively, for the poor profile group. We observed a strong time dependence of this signature, leading to an adjusted hazard ratio of 13.58 (1.85-99.63) and 8.20 (1.10-60.90) at 5 years and 5.11 (1.57-16.67) and 2.55 (1.07-6.10) at 10 years for time to distant metastasis and overall survival, respectively. CONCLUSION: This independent validation confirmed the performance of the 76-gene signature and adds to the growing evidence that gene expression signatures are of clinical relevance, especially for identifying patients at high risk of early distant metastases.

An international validation study of the EORTC brain cancer module (EORTC QLQ-BN20) for assessing health-related quality of life and symptoms in brain cancer patients.

Aims: The psychometric properties of the EORTC QLQ-BN20, a brain cancer-specific HRQOL questionnaire, have been previously determined in an English-speaking sample of patients. This study examined the validity and reliability of the questionnaire in a multi-national, multi-lingual study. Methods: QLQ-BN20 data were selected from two completed phase III EORTC/NCIC clinical trials in brain cancer (N=891), including 12 languages. Experimental treatments were surgery followed by radiotherapy (RT) and adjuvant PCV chemotherapy or surgery followed by concomitant RT plus temozolomide (TMZ) chemotherapy and adjuvant TMZ chemotherapy. Standard treatment consisted of surgery and postoperative RT alone. The psychometrics of the QLQ-BN20 were examined by means of multi-trait scaling analyses, reliability estimation, known groups validity testing, and responsiveness analysis. Results: All QLQ-BN20 items correlated more strongly with their own scale (r>0.70) than with other QLQ-BN20 scales. Internal consistency reliability coefficients were high (all alpha0.70). Known-groups comparisons yielded positive results, with the QLQ-BN20 distinguishing between patients with differing levels of performance status and mental functioning. Responsiveness of the questionnaire to changes over time was acceptable. Conclusion: The QLQ-BN20 demonstrates adequate psychometric properties and can be recommended for use in conjunction with the QLQ-C30 in assessing the HRQOL of brain cancer patients in international studies.