Variations in cuticular hydrocarbons of Calliphora vicina (Diptera: Calliphoridae) empty puparia: Insights for estimating late postmortem intervals.

Necrophagous flies, particularly blowflies, serve as vital indicators in forensic entomology and ecological studies, contributing to minimum postmortem interval estimations and environmental monitoring. The study investigates variations in the predominant cuticular hydrocarbons (CHCs) viz. n-C25, n-C27, n-C28, and n-C29 of empty puparia of Calliphora vicina Robineau-Desvoidy, 1830, (Diptera: Calliphoridae) across diverse environmental conditions, including burial, above-ground and indoor settings, over 90 days. Notable trends include a significant decrease in n-C25 concentrations in buried and above-ground conditions over time, while n-C27 concentrations decline in buried and above-ground conditions but remain stable indoors. Burial conditions show significant declines in n-C27 and n-C29 concentrations over time, indicating environmental influences. Conversely, above-ground conditions exhibit uniform declines in all hydrocarbons. Indoor conditions remain relatively stable, with weak correlations between weathering time and CHC concentrations. Additionally, machine learning techniques, specifically Extreme Gradient Boosting (XGBoost), are employed for age estimation of empty puparia, yielding accurate predictions across different outdoor and indoor conditions. These findings highlight the subtle responses of CHC profiles to environmental stimuli, underscoring the importance of considering environmental factors in forensic entomology and ecological research. The study advances the understanding of insect remnant degradation processes and their forensic implications. Furthermore, integrating machine learning with entomological expertise offers standardized methodologies for age determination, enhancing the reliability of entomological evidence in legal contexts and paving the way for future research and development.

Variant interpretation in molecular autopsy: a useful dilemma.

Sudden cardiac death (SCD) in adolescents and young adults may be the first manifestation of an inherited arrhythmic syndrome. Thus identification of a genetic origin in sudden death cases deemed inconclusive after a comprehensive autopsy and may help to reduce the risk of lethal episodes in the remaining family. Using next-generation sequencing (NGS), a large number of variants of unknown significance (VUS) are detected. In the majority of cases, there is insufficient evidence of pathogenicity, representing a huge dilemma in current genetic investigations. Misinterpretation of such variants may lead to inaccurate genetic diagnoses and/or the adoption of unnecessary and/or inappropriate therapeutic approaches. In our study, we applied current (ACMG) recommendations for variant classification in post-mortem genetic screening of a cohort of 56 SCD victims. We identified a total 53 rare protein-altering variants (MAF < 0.2%) classified as VUS or worse. Twelve percent of the cases exhibited a clinically actionable variant (pathogenic, likely pathogenic or VUS - potentially pathogenic) that would warrant cascade genetic screening in relatives. Most of the variants detected by means of the post-mortem genetic investigations were VUS. Thus, genetic testing by itself might be fairly meaningless without supporting background data. This data reinforces the need for an experienced multidisciplinary team for obtaining reliable and accountable interpretations of variant significance for elucidating potential causes for SCDs in the young. This enables the early identification of relatives at risk or excludes family members as genetic carriers. Also, development of adequate forensic guidelines to enable appropriate interpretation of rare genetic variants is fundamental.

Assessment of adherence to diuretics and ß-blockers by serum drug monitoring in comparison to urine analysis.

Purpose: Toxicological screenings for identifying antihypertensive drugs proved to be a useful tool for assessing adherence. However, misinterpretation may occur in case of highly metabolised drugs with low renal excretion, as well as for drugs with a prolonged detectability. The aim of the present study was to compare a recently developed therapeutic drug monitoring (TDM) method based on serum concentrations to an urine drug detection method for assessing adherence in outpatients.Materials and methods: Corresponding urine and blood samples were obtained at the same time from 26 outpatients without supervised medication. Urine and serum analyses were performed using established high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodologies. Adherence was assumed if drugs were detectable in urine or if serum concentrations were above individually calculated lower dose-related concentrations (DRC) or literature-based therapeutic reference ranges (TRR) used as cut-off, respectively.Results: The identification of analytes in urine as well as the quantitative serum assay were performed for atenolol (n = 6 patients), bisoprolol (n = 8), nebivolol (n = 6), canrenone (n = 6, metabolite of spironolactone), hydrochlorothiazide (n = 12) and furosemide (n = 2). On the basis of drug detectability in urine, adherence was assumed in 88% of prescriptions. In 81% (DRC) and 50% (TRR) of the serum analyses the cut-off value was exceeded, which confirms patients' adherence in a lower number. Differences in adherence rates were found in five patients, mainly for ß-blockers.Conclusion: This study suggests that assessment of adherence can be performed more precisely on the basis of serum drug concentrations with individually calculated lower DRC than by using the TRR or qualitative urinalysis.

Adherence to antihypertensive drug treatment in patients with apparently treatment-resistant hypertension in the INSPiRED pilot study.

PURPOSE: Drug adherence may be a major problem in the therapy of hypertension and in the diagnosis of therapy resistance. Adherence can be assessed by indirect methods or by direct methods like drug detection in urine with liquid chromatography-mass spectrometric methods. MATERIALS AND METHODS: The current analysis included patients with apparently treatment- resistant hypertension (TRH) referred for renal denervation (RDN) and included in the the INSPiRED pilot trial (NCT01505010). Adherence was repeatedly assessed by toxicological urine analysis over a time range of up to 17 months in a total of 18 patients. RESULTS: In the first urine samples of 18 patients the adherence rate (percentage of number of detected vs. prescribed medical drugs) ranged from 0 to 100% with a median of 73.2%. In further urine samples collected during the following up to 17 months every individual patient exhibited considerable changes in the adherence rate, neither a constancy nor a tendency could be deduced. CONCLUSIONS: Urine analysis results exhibit variation over time and an assessment at a certain time point cannot be regarded as representative or predictor for future behavior. Therefore, it appears necessary to perform drug adherence testing repeatedly over time.

Results of a randomized controlled pilot trial of intravascular renal denervation for management of treatment-resistant hypertension.

OBJECTIVE: Previous trials of catheter-based renal-artery denervation (RDN) as treatment modality in resistant hypertension (rHT) generated unconvincing results. In the Investigator-Steered Project on Intravascular Denervation for Management of Treatment-Resistant Hypertension (INSPiRED; NCT01505010), we optimized selection and management of rHT patients. METHODS: With ethical clearance to randomize 18 patients, three Belgian hypertension centers screened 29 rHT patients on treatment with ≥3 drugs, of whom 17 after optimization of treatment (age <70 years; systolic/diastolic office blood pressure (BP) ≥ 140/90 mm Hg; 24-h BP ≥130/80 mm Hg; glomerular filtration rate [eGFR] ≥ 45 mL/min/1.73 m2; body mass index <40kg/m2) were randomized and 15 were analyzed 6 months later, while medical treatment was continued (n = 9) or combined with RDN by the EnligHTN™ multi-electrode system (n = 6). RESULTS: The baseline-adjusted between-group differences amounted to 19.5/10.4 mm Hg (change in control vs. intervention group, +7.6/+2.2 vs. -11.9/-8.2 mm Hg; P = .088) for office BP, 22.4/13.1 mm Hg (+0.7/+0.3 vs. -21.7/-12.8; mm Hg; P ≤ .049) for 24-h BP, the primary efficacy endpoint, and 2.5 mL/min/1.73 m2 (+1.5 vs. -1.1 mL/min/1.73 m2; P = .86) for eGFR, the primary safety endpoint. At 6 month, ECG voltages and the number of prescribed drugs (P ≤ .036) were lower in RDN patients, but quality of life and adherence, captured by questionnaire and urine analysis were similar in both groups. Changes in BP and adherence were unrelated. No major complications occurred. CONCLUSIONS: The INSPiRED pilot suggests that RDN with the EnligHTN™ system is effective and safe and generated insights useful for the design of future RDN trials.

[Drinking study on the pharmacokinetics of the grappa congener 2-butanol].

A drinking study on the pharmacokinetics of the typical grappa congeners 2-butanol and 2-butanone (methyl ethyl ketone) was performed. It was expected that the concentration ratio might provide a means to estimate the time of ingestion of a grappa beverage. Twelve subjects drank a volume of the grappa "Vecchio di Prosecco" (42 vol%) to reach a blood alcohollevel of 1.20 %o. In the congener analyses in serum, a median 2-butanol concentration of 0.79 mg/1 (range 0.45-1.34 mg/1) and of 1.01 mg/I (0.44-1.62 mg/1) for 2-butanone were measured. The concentration-time curve was biphasic starting with a slow and plateau-like elimination. However, considerable inter-individual differences were observed. Only in 3 subjects, a 2-butanol : 2-butanone ratio below 1 suggested ingestion within the last 6 hours. The majority of the subjects exhibited higher concentrations of 2-butanone than of 2-butanol such that the ratio was always smaller than 1. According to the present results the concentrations of 2-butanol and 2-butanone or their ratio do not provide a reliable basis to draw conclusions on the time of grappa ingestion.

Field study to detect illicit and medicinal drugs in car drivers in Southern and Western Hesse.

In the present study, immunochemical tests (Mahsan DrugInspector, DOA4, DOA8, DOA10, Protzek) as well as the detection rate of police checks were evaluated. Urine and blood samples of suspected car drivers were analysed by chromatography-mass spectrometry. Additionally, anonymised urine samples were analysed on a voluntary basis in cases where no legal proceedings were initiated. Toxicological analyses (total unknown screening) were performed using gas chromatography-mass spectrometry (GC-MS) after hydrolysis, acidic and alkaline extraction and derivatization. A data base for screening 9000 substance entries was applied. In addition, urine samples were analysed using liquid chromatography/ time-of-flight mass spectrometry (HPLC-ToF-MS) to screen psychiatric and narcotic drugs. In total, samples of 154 suspects were analysed, of these, 46 samples for no actual reason. In 5 of the latter samples, forensically relevant substances were detected; in two cases the consumption of illicit drugs, i. e. cannabis and methamphetamine, was proved. Of the 154 suspects, 108 were charged with driving under the influence of drugs; in samples of 103 of these cases, illicit drugs were found. Immunochemical pretesting showed posi- tive results in 97 of the 108 cases; in 6 samples, psychiatric drugs (citalopram, doxepin, promethazine, mirtazapine, fluoxetine, venlafaxine) were later identified, which are not detectable by ordinary pretesting systems. Police officers successfully identified 95.4 % of the suspects as drug consumers, which is an excellent result. In practice, pretesting of urine samples using immunochemical techniques proved to be very reliable. The Protzek system in particular corresponded well with the results of the chromatographic analyses. In conclusion, systematic chromatographic-mass spectrometric analysis of urine samples of suspects is recommended to identify car drivers consuming illicit drugs and to obtain data usable in legal proceedings (e. g. suspending of the driving license), which is not always possible when using blood samples in cases of drugs consumed some time ago.

High variation of congener alcohols in apple wines.

Congener alcohol (CA) analysis became an important tool in forensic science to prove the kind of alcoholic beverage consumed. The aim of the present study was to determine the influence of yeast strain and apple variety on the formation of congener alcohols in self-produced apple wine. There exist data on CA patterns of industrially produced alcoholic beverages, but these are not available for apple wine. Must from five different commercial as well as from six genuine apple varieties were used for fermentation under similar conditions CA formation was monitored during the fermentation process. Additionally, nine commercial apple wines from commercial producers were analyzed. Analysis was performed by headspaces-GC-MS. All apple wines contained markedly high contents of the CA 3-methylbutan-1-ol (88-251 mg/L). Compared to self-produced apple wines from genuine musts the industrial apple wines (purchased in supermarkets and self-produced from commercial musts) exhibited significant differences in methanol concentrations(8.5-94 mg/L), whereas all other CAs, such as propan-1-ol, butan-1-0l, 2-methylpropan-1-ol(isobutanol), 3-methyl-butan-1-oi, and 2-methylbutan-1-oi, were found to be present in similar concentrations. Methanol was not detectable in apple wine made from genuine musts during fermentation but after a storage period. In some cases, concentrations of some CAs additionally changed during storage. This may be explained by a secondary (unwanted) fermentation after bottling. According to the data obtained in the present study, it is recommended to analyze a sample of the allegedly consumed apple wine in forensic cases, rather than to rely on data obtained from the literature or from some data collections.

Sleep self-intoxication and sleep driving as rare zolpidem-induced complex behaviour.

INTRODUCTION: The GABA(A) receptor agonist zolpidem has been used for treatment of insomnia since years, but special side effects have been reported. These side effects were called zolpidem-induced sleep-related complex behaviour. Such complex behaviour is associated with somnambulism and includes sleepwalking, sleep eating, sleep conversation and sleep driving. CASE PRESENTATION: Two cases of zolpidem-induced sleep-related complex behaviour following self-intoxication, sleep driving and amnesia are presented. In both cases, the subjects reported the voluntary intake of only one zolpidem tablet of 10 mg and amnesia for the time afterwards. Shortly after the onset of the drug's action, both individuals drifted into a somnambulism-like state and toxicological blood analysis suggested the intake of the remaining zolpidem tablets which might be called "sleep intoxication". Later, the subjects were arrested by police after driving under drug influence and not realizing the situation. Retrospectively, both subjects suffered from psychiatric disorders and in case 2, the subject was treated for depression with doxepin. Consequently, these co-factors may have increased the risk for the occurrence of the sleep-related complex behaviour. DISCUSSION: Involuntary self-intoxication should be taken into account in addition to the known pattern of zolpidem-induced complex behaviour. In legal cases, the forensic expert has to assess the blood concentration of zolpidem in evaluating this strange behaviour. CONCLUSION: Amnesia and incoherence of speech, disorganization of behaviour, inability to realize the situation and mood changes may indicate a zolpidem-induced somnambulism-like state with sleep-related complex behaviour.

Pitfall in cannabinoid analysis--detection of a previously unrecognized interfering compound in human serum.

In clinical and forensic toxicology, high-performance liquid chromatography/tandem mass spectrometry (LC-MS/MS) is increasingly used since it allows the development of sensitive and fast drug analysis procedures. During development of a LC-MS/MS method for determination of the psychoactive cannabinoid Δ(9)-tetrahydrocannabinol (THC) and of its two metabolites 11-hydroxy-THC (THCOH) and 11-nor-9-carboxy-THC (THCCOOH) in serum, a previously unrecognized interfering compound was detected. Extending the fast gradient elution program by an isocratic phase leads to sufficient separation of the interfering compound, initially co-eluting with THCCOOH and exhibiting the same fragments. For characterization, product ion scans and precursor ion scans were performed. Samples from cannabis users were analyzed to estimate the abundance of the interfering compound. The mass spectrometric experiments showed that the interfering compound exhibited the same molecular mass as THCCOOH and a similar fragmentation pattern except for relative fragment intensities. This compound was exclusively detectable in authentic samples. Concentrations were in the range of 4.5 to 51 % (median 14.6 %, n = 73) of those of THCCOOH. After further optimization of the gradient, the method was sufficiently selective and sensitive and validation parameters were within acceptance limits. A new compound related to cannabis use was detected in human serum, and data suggest an isomeric structure to THCCOOH. Considering the rather high amounts observed, it was surprising that this compound had not been detected previously. Further studies on its structure and origin are necessary.

[How relevant is the risk of losing evidence due to delayed blood sampling? Conclusions from the evaluation of blood analysis results]. / Wie relevant ist die Gefahr des Beweismittel- verlustes bei verzögerter Blutentnahme? Schlussfolgerungen aus der Auswertung von Blutuntersuchungsergebnissen.

If the order of a judge to take a blood sample can only be obtained with a marked delay after the incident, evidence proving that a suspect had been driving under the influence of alcohol or drugs of abuse may be lost. The evaluation of blood analysis results from the Institute of Legal Medicine in Frankfurt/Main from the years 2012-2014 shows that in 1.6 to 11.6% of positive cases, the drug concentrations were near the legal limits (20.2% of alcohol-positive and 7.5% of illicit drugs-positive samples). A loss of evidence can thus be expected in a large number of cases when the time between the police check of a driver and the collection of a blood sample increases. Blood concentrations of alcohol and drugs of abuse, especially tetrahydrocannabinol, cocaine, methamphetamine, and morphine, may already have dropped significantly after a delay of only half an hour. These delays are typically due to the time elapsing until the order to take a blood sample has been obtained from a judge and a medical doctor becomes available and arrives at the police station to draw a blood sample. The recommendation of medicolegal experts is to keep the time between police check of a suspect and blood sampling as short as possible. In routine cases, a realistic maximum of one hour should not be exceeded.

Deciphering the impact of microenvironmental factors on cuticular hydrocarbon degradation in Lucilia sericata empty Puparia: Bridging ecological and forensic entomological perspectives using machine learning models.

Blow flies (Calliphoridae) play essential ecological roles in nutrient recycling by consuming decaying organic matter. They serve as valuable bioindicators in ecosystem management and forensic entomology, with their unique feeding behavior leading to the accumulation of environmental pollutants in their cuticular hydrocarbons (CHCs), making them potential indicators of exposure history. This study focuses on CHC degradation dynamics in empty puparia of Lucilia sericata under different environmental conditions for up to 90 days. The three distinct conditions were considered: outdoor-buried, outdoor-above-ground, and indoor environments. Five predominant CHCs, n-Pentacosane (n-C25), n-Hexacosane (n-C26), n-Heptacosane (n-C27), n-Octacosane (n-C28), and n-Nonacosane (n-C29), were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). The findings revealed variations in CHC concentrations over time, influenced by environmental factors, with significant differences at different time points. Correlation heatmap analysis indicated negative correlations between weathering time and certain CHCs, suggesting decreasing concentrations over time. Machine learning techniques Support Vector Machine (SVM), Multilayer Perceptron (MLP), and eXtreme Gradient Boosting (XGBoost) models explored the potential of CHCs as age indicators. SVM achieved an R-squared value of 0.991, demonstrating high accuracy in age estimation based on CHC concentrations. MLP also exhibited satisfactory performance in outdoor conditions, while SVM and MLP yielded unsatisfactory results indoors due to the lack of significant CHC variations. After comprehensive model selection and performance evaluations, it was found that the XGBoost model excelled in capturing the patterns in all three datasets. This study bridges the gap between baseline and ecological/forensic use of empty puparia, offering valuable insights into the potential of CHCs in environmental monitoring and investigations. Understanding CHCs' stability and degradation enhances blow flies' utility as bioindicators for pollutants and exposure history, benefiting environmental monitoring and forensic entomology.

Cuticular hydrocarbons as weathering biomarkers of empty puparia of the forensically important blowfly Calliphora vicina Robineau-Desvoidy, 1830 (Diptera: Calliphoridae) in soil v/s under room conditions.

Forensic entomology uses the age of insects, such as blow flies, to determine a minimum post-mortem interval (PMImin). Recent research has focused on using the analysis of specific cuticular hydrocarbons (CHCs) in adult insects and their empty puparia to estimate their age, as it has been shown that their profile changes are consistent with age. The current work is based on the weathering of five CHCs from empty puparia of Calliphora vicina that were stored in soil (field/outdoor) and non-soil (room/indoor conditions) based pupariation media for a total of six months. The experiment was conducted in a controlled environment chamber at a constant temperature of 25 ± 2 °C under constant darkness. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the cuticular hydrocarbons after they were extracted in n-Hexane. n-Pentacosane, n-Hexacosane, n-Heptacosane, n-Octacosane, and n-Nonacosane were the five CHCs investigated. Results showed that CHCs weathered more quickly in the soil than in the non-soil environment. It was also found that the abundance of Heptacosane increased in the samples during the fifth month when stored in a non-soil medium, while the abundances of all five CHCs were not detected after eight weeks onwards in soil pupation medium.

Analysis of tetramisole metabolites - Is "Aminorex" found in forensic samples of cocaine users actually 4-phenyl-2-imidazolidinone?

Phenyltetrahydroimidazothiazole (PTHIT, tetramisole) is a common adulterant in cocaine samples. Little is known about its human metabolism. p-hydroxy-PTHIT has long been the only proven phase-I-metabolite. Another putative metabolite is the stimulant aminorex. However, data on its analytical proof is rare and contradictory. Even less known is its constitutional isomer 4-phenyl-2-imidazolidinone which has only been proven in animal samples so far. The aim of the study was to get insight into the metabolism of PTHIT after controlled nasal uptake of PTHIT and in real forensic cocaine/benzoylecgonine-positive samples. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was validated for quantification of 4-phenyl-2-imidazolidinone and p-hydroxy-PTHIT (LOQ 0.05 ng/ml each). Selectivity was ensured for 4-phenyl-2-imidazolidinone and aminorex (LOD 0.05 ng/ml). After controlled nasal uptake of tetramisole (10 mg, n = 3) a shorter half-life for p-hydroxy-PTHIT (3.4-5.8 h) was determined than for 4-phenyl-2-imidazolidinone (14.0-15.9 h). p-hydroxy-PTHIT (33%) and 4-phenyl-2-imidazolidinone (51%) were also detected in serum samples from cocaine users tested previously positive for PTHIT (n = 73). Aminorex was never detected. The potential of misinterpreting 4-phenyl-2-imidazolidinone as aminorex was tested using a gas chromatography-mass spectrometry (GC-MS) method used in the literature and an in-house liquid chromatography-time-of-flight mass spectrometry (LC-QTOF) screening-method. Using GC-MS the analysed bis-trimethylsilyl-derivatives cannot be differentiated due to co-elution. Both substances were chromatographically separated using the LC-QTOF method, but library comparison workflows misinterpreted 4-phenyl-2-imidazolidinone as aminorex. It seems likely that aminorex, which was allegedly identified as a metabolite of PTHIT in samples of cocaine users in previous studies, is in fact 4-phenyl-2-imidazolidinone.

Missed chances? Sequestration and non-sequestration of alkaloids by moths (Lepidoptera).

Some butterflies and moths sequester and retain noxious phytochemicals for defence against predators. In the present study, three moth species, the garden tiger moth, Arctia caja, the death hawk moth, Acherontia atropos, and the oleander hawk moth, Daphnis nerii, were tested whether they sequester alkaloids from their host plants. Whereas A. caja consistently sequestered atropine from Atropa belladonna, also when atropine sulfate was added to the alkaloid-free diet of the larvae, A. atropos and D. nerii were found to be unable to sequester alkaloids, neither atropine nor eburnamenine from Vinca major, respectively. Instead of acquiring toxicity as chemical defence, nocturnal lifestyle and cryptic attitudes may improve their chances of survival.

Analysis of lysergic acid amide in human serum and urine after ingestion of Argyreia nervosa seeds.

The ergot alkaloid lysergic acid amide (LSA) is a secondary plant constituent in a number of plants, but it is mainly present in considerable amounts in Convolvulaceae, like Argyreia nervosa. Due to its close structural similarity to lysergic acid diethylamide, LSA is considered as psychedelic and therefore promoted as so-called "legal high" in various internet forums. During a human behavioral study with orally administered seeds of A. nervosa, blood and urine samples were obtained. The present study describes the validation of a sensitive and robust high performance liquid chromatography method with fluorescence detection, which was applied to the study samples. The limit of detection (LOD) and lower limit of quantification in human serum were 0.05 and 0.17 ng/mL, respectively, and in urine, the LOD was 0.15 ng/mL. Intra- and interday precision and accuracy were below 15 % relative standard deviation with a bias better than ±15 %. No conversion of LSA to its epimer iso-LSA was noted during analyses. The LSA concentrations in the authentic human serum samples were in the range of 0.66 to 3.15 ng/mL approximately 2 h after ingestion. In urine, LSA could be found 1-24 h after ingestion; after 48 h, no LSA could be detected. The LSA epimer iso-LSA was also detected in serum and urine in varying ratios. In conclusion, LSA serum levels in the low nanogram per milliliter range correlated with severe vegetative adverse effects (nausea, weakness, fatigue, tremor, blood pressure elevation) and a psychosis-like state, which led to study termination.

Influence of ethanol on cannabinoid pharmacokinetic parameters in chronic users.

Cannabis is not only the most widely used illicit drug worldwide but is also regularly consumed along with ethanol. In previous studies, it was assumed that cannabis users develop cross-tolerance to ethanol effects. The present study was designed to compare the effects of ethanol in comparison to and in combination with a cannabis joint and investigate changes in pharmacokinetics. In this study, 19 heavy cannabis users participated and received three alcohol dosing conditions that were calculated to achieve steady blood alcohol concentrations (BAC) of about 0, 0.5 and 0.7 g/l during a 5-h time window. Subjects smoked a Δ(9)-tetrahydrocannabinol (THC) cigarette (400 µg/kg) 3 h post-onset of alcohol dosing. Blood samples were taken between 0 and 4 h after smoking. During the first hour, samples were collected every 15 min and every 30 min thereafter. Mean steady-state BACs reached 0, 0.36 and 0.5 g/l. The apparent elimination half-life of THC was slightly prolonged (1.59 vs. 1.93 h, p < 0.05) and the concentration 1 h after smoking was slightly lower (24 vs. 17 ng/ml, p < 0.05) with the higher ethanol dose. The prolonged THC elimination might be explained by a small ethanol-mediated change in distribution to and from deep compartments. Concentrations and pharmacokinetics of 11-hydroxy-THC and 11-nor-9-carboxy-THC (THCA) were not significantly influenced by ethanol. However, THCA concentrations appeared lower in both ethanol conditions, which might also be attributable to changes in distribution. Though not significant in the present study, this might be relevant in the interpretation of cannabinoid concentrations in blood.

Assay of ethanol and congener alcohols in serum and beverages by headspace gas chromatography/mass spectrometry.

The analysis of ethanol and of its congeners in blood plays an important role in forensic cases, especially when allegations are made that alcohol has been consumed after an accident. In alcoholic beverages, congener alcohols are by-products and are generated during fermentation. The assay of these compounds in serum samples and beverages has been previously performed using headspace-gas chromatography-flame ionization detection methods (HS-GC-FID). As an alternative, a robust headspace-gas chromatography-mass spectrometry (HS-GC-MS) procedure was developed and validated, which has the following advantages:•Simultaneous determination of ethanol, congener alcohols and other endogenous substances.•Reduction of matrix interference by increasing selectivity and specificity.•Clear separation of the positional isomers 3-methyl-1-butanol and 2-methyl-1-butanol.

Endogenous formation of 1-propanol and methanol after consumption of alcoholic beverages.

INTRODUCTION: In cases of drunk-driving, allegations that alcohol has been consumed after the incident, are proved by analyzing congener alcohols in the blood sample. 1-Propanol, one of the main congener compounds, was tested, whether it is also endogenously formed when a person has consumed alcoholic beverages. METHODS: Eleven male and 13 female volunteers consumed congener-free vodka (37.5 vol% ethanol, individual doses: 0.15-0.32 l) within one hour. Blood samples were taken up to 10 h and analyzed for ethanol and congener alcohols by headspace gas chromatography-mass spectrometry. RESULTS: Ethanol concentrations reached in blood a maximum of 0.65-1.23 g/l and decreased by 0.18 g/l/h (median values). Of the congener alcohols analyzed, only methanol and 1-propanol were detected in the plasma samples of all subjects. The endogenous methanol concentration increased from 0.66 mg/l by 0.22 mg/l/h to 2.19 mg/l (medians). 1-Propanol was not detected prior to alcohol consumption. Maximum concentrations of 0.10-0.32 mg/L were measured after 1.0-4.5 h. A plateau of the 1-propanol concentration was observed in the plasma samples of the 18 subjects lasting for 0.5-4.0 h and this alcohol was completely eliminated at ethanol concentrations of 0.17 g/l (median, range 0.03-0.55 g/l). CONCLUSION: The results of the study confirm the formation of 1-propanol after consumption of 1-propanol-free beverages, which should be taken into account when evaluating its concentration.

[Interpretation of blood analysis data found after passive exposure to cannabis]. / Interpretation analytischer Befunde in Blutproben bei passiver Cannabisexposition.

When defendants are confronted with evidence of cannabinoids in their blood suggesting consumption of cannabis they sometimes argue that this could only be due to a passive exposure. The small number of controlled studies available showed that tetrahydrocannabinol (THC), the active ingredient of cannabis, was actually found in the blood after passive exposure to cannabis smoke. The resulting blood concentrations were dependent on the applied THC doses and the size of the room in which the passive exposure occurred. However, the quantitative data indicated in the publications of the 1980s cannot be fully compared with the results of modern analytical methods. Due to the rapid distribution of THC in the body, which occurs also after passive exposure to low doses, the THC concentration in serum to be expected in a blood sample taken 1 hour after exposure is less than 1 ng/mL. For assessment of an alleged passive exposure, the metabolic THC-carboxylic acid, which is excreted more slowly, must also be taken into account. After passive exposure, similar and very low serum concentrations of THC and THC-carboxylic acid are to be expected (< 2 ng/mL), while higher blood levels suggest the deliberate consumption of a psychoactive dose.