Improving detection of rare biological events in high-throughput screens.

The success of high-throughput screening (HTS) strategies depends on the effectiveness of both normalization methods and study design. We report comparisons among normalization methods in two titration series experiments. We also extend the results in a third experiment with two differently designed but otherwise identical screens: compounds in replicate plates were either placed in the same well locations or were randomly assigned to different locations. Best results were obtained when randomization was combined with normalization methods that corrected for within-plate spatial bias. We conclude that potent, reliable, and accurate HTS requires replication, randomization design strategies, and more extensive normalization than is typically done and that formal statistical testing is desirable. The Statistics and dIagnostic Graphs for HTS (SIGHTS) Microsoft Excel Add-In software is available to conduct most analyses reported here.

Simultaneous determination of tramadol, O-desmethyltramadol and N-desmethyltramadol in human urine by gas chromatography-mass spectrometry.

Analytical procedures for the determination of tramadol (T), O-desmethyltramadol (ODT), and N-desmethyltramadol (NDT) in human urine have been developed and validated using gas chromatography-mass spectrometry (GC/MS). Sample preparation involved liquid-liquid extraction with methyl-tert-butyl ether (MTBE) and followed by back extraction with 0.1 M hydrochloric acid. Proadifen (SKF525A) was selected as internal standard (IS). Extraction efficiencies of T, ODT and NDT were 102.12, 101.30, and 98.21%, respectively. The calibration curves were linear (r(2)>0.99) in the concentration range 10-1000 ng/mL for all compounds. Limits of quantification (LOQ) were 10, 10 and 20 ng/mL for T, ODT and NDT, respectively. Intra-assay precision was within 1.29-6.48% and inter-assay precision was within 1.28-6.84% for T, ODT and NDT. Intra-assay accuracy was within 91.79-106.89% for all analytes. This method detected urine concentrations of T, ODT and NDT in six healthy volunteers for 7 days after administration of 50 mg oral doses of tramadol.

Overview of literature and information on "khat-related" mortality: a call for recognition of the issue and further research.

During the past 20 years or so, more has become known about the properties of khat, its pharmacology, physiological and psychological effects on humans. However, at the same time its reputation of social and recreational use in traditional contexts has hindered the dissemination of knowledge about its detrimental effects in terms of mortality. This paper focuses on this particular deficit and adds to the knowledge-base by reviewing the scant literature that does exist on mortality associated with the trade and use of khat. We sought all peer-reviewed papers relating to deaths associated with khat. From an initial list of 111, we identified 15 items meeting our selection criteria. Examination of these revealed 61 further relevant items. These were supplemented with published reports, newspaper and other media reports. A conceptual framework was then developed for classifying mortality associated with each stage of the plant's journey from its cultivation, transportation, consumption, to its effects on the human body. The model is demonstrated with concrete examples drawn from the above sources. These highlight a number of issues for which more substantive statistical data are needed, including population-based studies of the physiological and psychological determinants of khat-related fatalities. Khat-consuming communities, and health professionals charged with their care should be more aware of the physiological and psychological effects of khat, together with the risks for morbidity and mortality associated with its use. There is also a need for information to be collected at international and national levels on other causes of death associated with khat cultivation, transportation, and trade. Both these dimensions need to be understood.

Energy-1 ('NRG-1'): don't believe what the newspapers say about it being legal.

A 31-year-old man purchased the legal high Energy-1 (NRG-1) over the internet; this was advertised as containing the compound naphthylpyrovalerone (NPV), which at the time was currently legally available in the UK. He ingested 1 g of this substance and developed a prolonged high associated with palpitations, sweating and insomnia. Analysis of both the powder and serum samples from the patient demonstrated that he ingested two classified recreational drugs ß-keto-N-methylbenzodioxolylpropylamine (butylone) and methylenedioxypyrovalerone (MDPV) rather than the legal substance NPV. Users of legal highs need to be aware that legal highs purchased over the internet may contain illegal substances and therefore they may be liable for prosecution if found in possession of these substances. Future educational campaigns aimed at recreational drug and legal high users should include reference to the potential legal implications of buying these substances.

Energy-1 ('NRG-1'): don't believe what the newspapers say about it being legal.

A 31-year-old man purchased the legal high Energy-1 (NRG-1) over the internet; this was advertised as containing the compound naphthylpyrovalerone (NPV), which at the time was currently legally available in the UK. He ingested 1 g of this substance and developed a prolonged high associated with palpitations, sweating and insomnia. Analysis of both the powder and serum samples from the patient demonstrated that he ingested two classified recreational drugs ß-keto-N-methylbenzodioxolylpropylamine (butylone) and methylenedioxypyrovalerone (MDPV) rather than the legal substance NPV. Users of legal highs need to be aware that legal highs purchased over the internet may contain illegal substances and therefore they may be liable for prosecution if found in possession of these substances. Future educational campaigns aimed at recreational drug and legal high users should include reference to the potential legal implications of buying these substances.

Two UK suicides using nicotine extracted from tobacco employing instructions available on the Internet.

Tobacco is one of the most easily accessible and commonly abused drugs world-wide. Nicotine, one of its principal constituents, can cause serious or fatal overdoses. Whilst the deliberate ingestion of this substance appears to be relatively rare, often the important signs of its consumption are not recognised, sometimes with fatal results. Here we describe two cases of intentional fatal ingestion of nicotine. The nicotine was extracted from tobacco using instructions available on the Internet. The first case involved a male aged 19 who died in 2008. The post-mortem blood and urine levels of nicotine were 5.5mg/l and >80 mg/l respectively; the blood level is in line with the generally recognised fatal level of >5mg/l. The levels of nicotine's main metabolite, cotinine, for this case were 2.5mg/l and 7.9 mg/l for blood and urine respectively. A comparative case in 1999 involved a 32 year-old male. The level of post-mortem nicotine in his blood was 1.0mg/l. These are believed to be the first UK suicides by nicotine using instructions from the Internet reported in the literature. Information that nicotine was the agent responsible only became apparent some time after death. There may be more deaths due to this cause that go unrecognised because quantification of nicotine and cotinine levels is not often conducted, due to the wide prevalence of smoking. It is important that all evidence at the scene of a sudden and unexplained death is carefully evaluated, including potential clues on PCs and lap-tops.