Deposition of cannabinoids in hair after long-term use of cannabis

Hair analysis has shown great potential in the detection and control of drug use. Whether an assay is of quantitative value roughly corresponding to the amount of drug consumed, is still a matter of debate. The present investigation was aimed at a possible relationship between the cannabinoid concentration in hair and the cumulative dose in regular users of cannabis. Hair samples from the vertex region of the scalp were obtained from 12 male regular users of cannabis, and 10 male subjects with no experience of cannabis served as controls. None of the subjects had his hair permed, bleached or colored. Cannabis users provided information on drug use such as the current cannabis dose per day, the cumulative cannabis dose of the last 3 months, as well as the frequency of cannabis use during the last year. The concentration of delta-9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) in hair was determined using gas chromatography-mass spectrometry. Cannabinoids were present in any hair sample of cannabis users, but were not detectable in control specimens. An increase in the amount of cannabinoids in hair with increasing dose was evident. The concentration of major cannabinoids (sum of THC, CBD and CBN) was significantly correlated to either the reported cumulative cannabis dose during the last 3 months or to the cannabis use during the last 3 months estimated from the daily dose and the frequency per year (r=0.68 or 0.71, p=0.023 or 0.014). A significant relationship between THC and the amount of cannabis used could not be established. As a conclusion, the sum of major cannabinoids in hair of regular users may provide a better measure of drug use than THC.     

Estimation of age at death from the pubic symphysis and the auricular surface of the ilium using a smoothing procedure

We discuss here the estimation of age at death from two indicators (pubic symphysis and the sacro-pelvic surface of the ilium) based on four different osteological series from Portugal, Great-Britain, South Africa or USA (European origin). These samples and the scoring system of the two indicators were used by Schmitt et al. (2002), applying the methodology proposed by Lucy et al. (1996). In the present work, the same data was processed using a modification of the empirical method proposed by Lucy et al. (2002). The various probability distributions are estimated from training data by using kernel density procedures and Jackknife methodology. Bayes's theorem is then used to produce the posterior distribution from which point and interval estimates may be made. This statistical approach reduces the bias of the estimates to less than 70% of what was obtained by the initial method. This reduction going up to 52% if knowledge of sex of the individual is available, and produces an age for all the individuals that improves age at death assessment.     

Does a positive finding of tetrahydrocannabinol in the blood result from ingestion of Indian frankincense (Boswellia serrata)?

The exculpatory statement that a positive THC finding in the blood is due to the consumption of hemp products or passive exposure to cannabis smoke has been disproved by the monitoring of hemp products and recent passive inhalation studies conducted in social settings, which showed that these conditions are unlikely to produce a positive result in the blood. The defense that the ingestion of Indian olibanum may result in a positive THC concentration in the blood is unusual; it is based on older publications where authors had speculated on a possible association of the synthetic pathways of THC from terpenoid precursors also being present in olibanum and the biogenesis of THC in hemp. It had further been speculated whether chemical or plant-derived pathways may also occur in humans. A thorough understanding of the different pathways and recently published results have outdated these speculations.