Post mortem concentrations of endogenous gamma hydroxybutyric acid (GHB) and in vitro formation in stored blood and urine samples

The interest of using vitreous humor for γ-hydroxybutyrate (GHB) quantification in related fatalities: Stability evaluation, case report and literature review

Analysis and interpretation of the findings for γ-hydroxybutyrate (GHB) in related fatalities remains problematic. Indeed, GHB is a naturally occurring compound present in both the mammalian central nervous system and peripheral tissue. Moreover, a postmortem increase in endogenous GHB concentration has been observed, especially in blood. Facing this issue, the use of an alternative matrix such as vitreous humor (VH) can thus be particularly interesting for GHB testing and quantification. VH is considered to be less prone to postmortem redistribution, is easy to collect, and has relatively few interfering compounds for the analytical process. In this context, the authors report the case of a GHB-related fatality involving 22-year-old male. In this case, GHB femoral blood (FB) (790 mg/L) and vitreous (750 mg/L) concentrations appeared similar with a FB to VH (FB/VH) ratio of 1.05. In addition, other similar cases with both GHB blood and vitreous concentrations were reviewed. Five cases were identified. The blood to VH ratios ranging from 0.13 to 2.58. Finally, GHB stability was documented in postmortem blood and VH, in order to address the reliability of VH as an alternative matrix for GHB quantitation at postmortem. GHB appeared relatively stable in postmortem blood specimens (at 50 mg/L) over a period of 28 days when stored at +4 °C or -20 °C. The same results were observed in VH specimens.

Gamma-hydroxybutyrate (GHB), 1,4-butanediol (1,4BD), and gamma-butyrolactone (GBL) intoxication: A state-of-the-art review

γ-hydroxybutyrate (GHB) is synthesized endogenously from γ-aminobutyric acid (GABA) or exogenously from 1,4-butanediol (butane-1,4-diol; 1,4-BD) or γ-butyrolactone (GBL). GBL, and 1,4-BD are rapidly converted to GHB. The gastric absorption time, volume of distribution, and half-life of GHB are between 5 and 45 min, 0.49 ± 0.9 L/kg, and between 20 and 60 min, respectively. GHB and its analogues have a dose-dependent effect on the activation of GHB receptor, GABA-B, and GABA localized to the central nervous system. After ingestion, most patients present transient neurological disorders (lethal dose: 60 mg/kg). Chronic GHB consumption is associated with disorders of use and a withdrawal syndrome when the consumption is discontinued. GHB, GBL, and 1,4-BD are classified as narcotics but only the use of GHB is controlled internationally. They are used for drug facilitated (sexual) assault, recreational purposes, slamsex, and chemsex. To confirm an exogenous intake or administration of GHB, GBL, or 1-4-BD, the pre-analytical conservation is crucial. The antemortem cutoff doses for detection are 5 and 5-15 mg/L, with detection windows of 6 and 10 h in the blood and urine, respectively Control of GHB is essential to limit the number of users, abuse, associated risks, and death related to their consumption.

Complications in post-mortem GHB cut-off values in urine samples: A case report

Gamma-hydroxybutyric acid (GHB) is a drug of abuse, that interplays with a GABAergic system, resulting in an euphoric state and increased mood and impulses. Two cases of fatal mixed intoxications including GHB intake are presented here. In both cases, GHB was used together with multiple other drugs. Interpretation of GHB cut-off values are complicated in post-mortem analysis, because GHB can be post-mortem formed. The post-mortem GHB formation is dependent of the post-mortem interval (PMI) and the storage conditions of the samples. The GHB concentrations in urine are more stable compared to blood samples, when the samples are stored at the correct way at - 20 °C. Therefore, urine is the recommended matrix to analyze in toxicological screenings, since it allows more specific determination of exposure to exogenous GHB. Different cut-off values are used for matrices from living and deceased people. A cut-off value of 30 mg/L is recommended to discriminate between endogenous concentrations and concentrations resulting from exogenous GHB exposure. Moreover, post-mortem GHB formation can take place before sampling. However, when the samples are immediately stored at cooled conditions, no in vitro formation of GHB will take place. Urinary screening of GHB may serve as an initial screening for estimation of exposure of GHB in the body. However, additional quantitative GHB analysis in blood is required to estimate GHB exposure at the time of death. Furthermore, to obtain more reliable results for the ante-mortem GHB exposure, it may be useful to measure other biomarkers, like some GHB metabolites, especially in blood.

A Forensic Diagnostic Algorithm for Drug-Related Deaths: A Case Series

The best evidence provided in the literature worldwide suggests the importance of harmonizing the investigation in drug-related fatalities. In this study, the application of a multidisciplinary approach in eight cases of drug-related deaths is presented. Although death scene findings could be highly suggestive of drug intoxication, external examination and toxicological screening test alone are insufficient. There are several variables, and it is not always easy to give the proper interpretation of the drug detection. A complete autopsy is necessary to correctly complete organ and tissues sampling for further histological and toxicological studies and obtain body fluids. The use of peripheral blood is recommended to avoid artifacts. The collection of many specimens is warranted to get more responses. The sampling aims to provide a picture of the distribution of the substance in the body. The sample and the selection of the drugs and the matrices to investigate are case-dependent. The presented diagnostic algorithm provides the coroner with all the elements to investigate drug-related deaths and cooperate with toxicologists. Toxicological forensic diagnosis is still extremely heterogeneous in regional and national contexts. Funding for method development, research, networking, facilities, and technologies improvement is mandatory to standardize the toxicological investigation.

Comparative Study: Postmortem Long-Term Stability of Endogenous GHB in Cardiac Blood, Femoral Blood, Vitreous Humor, Cerebrospinal Fluid, and Urine with and Without Sodium Fluoride Stabilization

The interpretation of postmortem γ-hydroxybutyric acid (GHB) concentrations is challenging due to endogenous existence and postmortem GHB-production in body tissues and fluids. As an additional complication, formation of GHB was also described in stored postmortem samples. We examined cardiac blood, femoral blood, vitreous humor, cerebrospinal fluid, and urine of eight different corpses (male/female 5/3, aged 33-92 years, postmortem interval 1-6 days) where no intake of GHB or one of its precursors was assumed. All samples were collected during autopsy and divided into two aliquots. To one of the aliquots sodium fluoride (NaF, 1% w/v) was added. Both aliquots were vortexed, further divided into seven aliquots and stored at -20 °C. GHB concentrations were measured immediately and subsequently one day, seven days, two weeks, four weeks, three months, and six months, after sample collection using trimethylsilyl derivatization and gas chromatography, coupled to single quadrupole mass spectrometry (GC-MS). Similar progression curves of GHB concentrations were obtained for the different matrices in the individual corpses. Femoral and cardiac blood GHB concentrations were always found to be higher than in vitreous humor, cerebrospinal fluid, and urine irrespective of stabilization and storage time. None of the obtained GHB concentrations exceed the cut-off values for postmortem matrices commonly used for the identification of an exogenous GHB intake (urine, venous blood, and cerebrospinal fluid: 30 mg/l, cardiac blood, and vitreous humor 50 mg/l). No significant differences were found for the GHB concentrations measured immediately and six months after autopsy. However, we found a significant increase for the GHB concentrations four weeks as well as three months after sample collection which was followed by a decrease nearly to initial values. There were no significant differences between samples with and without NaF addition. The data presented are useful for the interpretation of GHB concentrations in upcoming death cases with special attention to storage conditions and different postmortem matrices.

Toxicological screening in the Amsterdam acute setting becomes more relevant if the standard panel of the drugs-of-abuse point-of-care test is expanded with GHB and ketamine

Objective

For diagnosis and treatment in the acute setting, it is crucial to know whether the clinical status of patients might be explained by the effects of drugs.The objective of this study was to determine how many drugs were detected by comprehensive toxicological screening, that could not be detected with a routine drugs-of-abuse point-of-care test (DOA-POCT) and which drugs of abuse (DOA) were relevant. A secondary objective was to determine in how many patients comprehensive toxicological screening provided additional clinically relevant information.

Methods

In this prospective study, patients were included in whom a DOA-POCT was performed and residual urine and serum samples were available.DOA-POCT were performed using the Triage® TOX Drug Screen. Comprehensive toxicological screening was performed using 1) the Toxtyper™ LC-MS^N method and 2) two GC-FID methods for alcohols and GHB respectively.The clinical relevance of the comprehensive toxicological screening results regarding diagnosis and patient management was quantified.

Results

A total of 100 patients were included. In 91 of these patients, comprehensive toxicological screening identified 234 drugs that were not identified by DOA-POCT. However, DOA-POCT identified 34 DOA that were not identified by comprehensive toxicological screening.Seven percent of comprehensive toxicological screening results were found to be clinically relevant, all with regard to diagnosis. GHB and ketamine were the drugs involved. Another 38 % strengthened confidence in diagnosis and patient care decisions.

Conclusion

GHB and ketamine should be added to the panel of drugs we screen at the point of care in the Amsterdam acute setting.

Gamma-hydroxybutyrate abuse: pharmacology and poisoning and withdrawal management

Gamma-hydroxybutyrate (GHB) is a central nervous system depressant primarily used as a recreational drug of abuse, but also for the treatment of narcolepsy with cataplexy in adult patients and as an adjuvant for control of alcohol withdrawal syndrome. The main aim of this review is to summarise updated knowledge about GHB pharmacokinetics and pharmacodynamics, acute poisoning, and clinical features of GHB withdrawal syndrome, its diagnosis and medical treatment. The most common clinical signs and symptoms of acute poisoning include sleepiness to deep coma, bradycardia, hypotension, and respiratory failure. Therapy is essentially supportive and based on continuous monitoring of vital signs. GHB withdrawal syndrome shares patterns with other withdrawal syndromes such as alcohol withdrawal and is sometimes difficult to distinguish, especially if toxicological tests are GHB-negative or cannot be performed. There are no official detoxification protocols for GHB withdrawal syndrome, but its therapy is based on benzodiazepine. When benzodiazepine alone is not effective, it can be combined with barbiturates or antipsychotics. Information about abuse and distribution of GHB and its precursors/analogues among the general population is still limited. Their prompt identification is therefore crucial in conventional and non-conventional biological matrices, the latter in particular, to clarify all the issues around this complex molecule.

The challenge of post-mortem GHB analysis: storage conditions and specimen types are both important

BACKGROUND

For the interpretation of concentrations of gamma-hydroxybutyrate (GHB) in post-mortem specimens, a possible increase due to post-mortem generation in the body and in vitro has to be considered. The influence of different storage conditions and the specimen type was investigated.

METHOD AND MATERIAL

Post-mortem GHB concentrations in femoral venous blood (VB), heart blood (HB), serum (S) from VB, urine (U), cerebrospinal fluid (CSF) and vitreous humour (VH) were determined by gas chromatography-mass spectrometry after derivatisation. Various storage conditions, that is 4 °C or room temperature (RT) and the addition of sodium fluoride (NaF), were compared during storage up to 30 days. Additionally, bacterial colonisation was determined by mass spectrometry fingerprinting.

RESULTS

Twenty-six cases without involvement of exogenous GHB were examined. GHB concentrations (by specimen) at day 0 were 3.9-22.1 mg/L (VB), 6.6-33.3 mg/L (HB), < 0.5-18.1 mg/L (U), 1.1-10.4 mg/L (CSF) and 1.7-22.0 mg/L (VH). At 4 °C, concentrations increased at day 30 to 5.6-74.5 mg/L (VB), 4.6-76.5 mg/L (HB) and < 0.5-21.3 mg/L (U). At RT, concentrations rose to < 0.5-38.5 mg/L (VB), 1.2-94.6 mg/L (HB) and < 0.5-37.5 mg/L (U) at day 30. In CSF, at RT, an increase up to < 0.5-21.2 mg/L was measured, and at 4 °C, a decrease occurred (< 0.5-6.5 mg/L). GHB concentrations in VH remained stable at both temperatures (1.2-20.9 mg/L and < 0.5-26.2 mg/L). The increase of GHB in HB samples with NaF was significantly lower than that without preservation. No correlation was found between the bacterial colonisation and extent of GHB concentration changes.

CONCLUSION

GHB concentrations can significantly increase in post-mortem HB, VB and U samples, depending on storage time, temperature and inter-individual differences. Results in CSF, VH, S and/or specimens with NaF are less affected.

State of the Art on Carbonic Anhydrase Modulators for Biomedical Purposes

The current review is intended to highlight recent advances in the search of new and effective modulators of the metalloenzymes Carbonic Anhydrases (CAs, EC 4.2.1.1) expressed in humans (h). CAs reversibly catalyze the CO2 hydration reaction, which is of crucial importance in the regulation of a plethora of fundamental processes at cellular level as well as in complex organisms. The first section of this review will be dedicated to compounds acting as activators of the hCAs (CAAs) and their promising effects on central nervous system affecting pathologies mainly characterized from memory and learning impairments. The second part will focus on the emerging chemical classes acting as hCA inhibitors (CAIs) and their potential use for the treatment of diseases.

Sudden cardiac death in anabolic androgenic steroids abuse: case report and literature review

Anabolic androgenic steroids (AAS) have several adverse effects on the cardiovascular system that may lead to a sudden cardiac death (SCD). We herein report a case involving a 24-year-old male, AAS abuser with intramuscular delivery in the 6 months before, who suffered a cardiorespiratory arrest at home’s bathtub when returning from New Year’s party. A forensic autopsy was performed according to the guidelines of the Association for European Cardiovascular Pathology (AECVP). The body showed hypertrophy of skeletal musculature, with low amount of subcutaneous fat and no signs of injury (body mass index, BMI: 26.8 kg/m²). On internal examination, there were multiorgan congestion, acute pulmonary edema, and cardiomegaly (420 g) with severe coronary atherosclerosis and superimposed acute occlusive thrombosis at the left main trunk and left anterior descendant. Areas of scarring were located at the intersection between the posterior wall and the posterior third of the septum (postero-septal). At histology, acute myocardial infarction at the anterior third of the septum and the anterior wall, and subacute myocardial infarction at apical septum and apical posterior wall were detected. Other findings were small intramyocardial vessel disease and myocytes hypertrophy. Chemicotoxicological analysis in blood showed ethanol ((0.90 ± 0.05) g/L), stanazolol (11.31 µg/L), nandrolone (2.05 µg/L) and testosterone (<1.00 µg/L). When confronted with a sudden death in a young athlete we must pay attention to the physical phenotype that may suggest AAS abuse and perform a detailed examination of the heart. Chemicotoxicological analysis is a key to establish the relationship between SCD and AAS abuse.

[The influence of the packaging on the storage qualities of the volatile substances]

The objective of the present study was to evaluate the storage qualities of the acetone and ethanol aqueous solutions kept in the polyethylene flasks, polypropylene and glass tubes that were stored under different environmental temperature. It was shown that the acetone aqueous solution better retained its properties when stored in glass vials at room temperature as well as at 0° C and 4° C. The most pronounced decrease of acetone concentrations (from 70 up to 95%) was documented after its storage in the polyethylene flasks. The ethanol concentration fell down by 40% when stored in polyethylene flasks at room temperature.

Synthesis of N'-phenyl-N-hydroxyureas and investigation of their inhibitory activities on human carbonic anhydrases

A series of N'-phenyl-N-hydroxyureas has been prepared by reacting hydroxylamine with aromatic isocyanates. These compounds were investigated as inhibitors of human carbonic anhydrases (hCAs, EC 4.2.1.1), considering four physiologically relevant isoforms, the cytosolic isoforms hCA I and II, and tumor associated, transmembrane isoforms hCA IX and XII. The new compounds reported here did not inhibit the widespread cytosolic isoforms hCA I and II, but they inhibited the tumor associated isoforms with interesting potencies. The most effective inhibitors showed K_Is ranging between 72.8 and 78.9 nM against hCA IX and between 6.9 and 7.2 against hCA XII, making them of interest as candidates for antitumor studies.

GHB pharmacology and toxicology: acute intoxication, concentrations in blood and urine in forensic cases and treatment of the withdrawal syndrome

The illicit recreational drug of abuse, γ-hydroxybutyrate (GHB) is a potent central nervous system depressant and is often encountered during forensic investigations of living and deceased persons. The sodium salt of GHB is registered as a therapeutic agent (Xyrem®), approved in some countries for the treatment of narcolepsy-associated cataplexy and (Alcover®) is an adjuvant medication for detoxification and withdrawal in alcoholics. Trace amounts of GHB are produced endogenously (0.5-1.0 mg/L) in various tissues, including the brain, where it functions as both a precursor and a metabolite of the major inhibitory neurotransmitter γ-aminobutyric acid (GABA). Available information indicates that GHB serves as a neurotransmitter or neuromodulator in the GABAergic system, especially via binding to the GABA-B receptor subtype. Although GHB is listed as a controlled substance in many countries abuse still continues, owing to the availability of precursor drugs, γ-butyrolactone (GBL) and 1,4-butanediol (BD), which are not regulated. After ingestion both GBL and BD are rapidly converted into GHB (t½ ~1 min). The Cmax occurs after 20-40 min and GHB is then eliminated from plasma with a half-life of 30-50 min. Only about 1-5% of the dose of GHB is recoverable in urine and the window of detection is relatively short (3-10 h). This calls for expeditious sampling when evidence of drug use and/or abuse is required in forensic casework. The recreational dose of GHB is not easy to estimate and a concentration in plasma of ~100 mg/L produces euphoria and disinhibition, whereas 500 mg/L might cause death from cardiorespiratory depression. Effective antidotes to reverse the sedative and intoxicating effects of GHB do not exist. The poisoned patients require supportive care, vital signs should be monitored and the airways kept clear in case of emesis. After prolonged regular use of GHB tolerance and dependence develop and abrupt cessation of drug use leads to unpleasant withdrawal symptoms. There is no evidence-based protocol available to deal with GHB withdrawal, apart from administering benzodiazepines.

Anabolic Androgenic Steroid (AAS) related deaths: autoptic, histopathological and toxicological findings

Anabolic androgenic steroids (AASs) represent a large group of synthetic derivatives of testosterone, produced to maximize anabolic effects and minimize the androgenic ones. AAS can be administered orally, parenterally by intramuscular injection and transdermally. Androgens act by binding to the nuclear androgen receptor (AR) in the cytoplasm and then translocate into the nucleus. This binding results in sequential conformational changes of the receptor affecting the interaction between receptor and protein, and receptor and DNA. Skeletal muscle can be considered as the main target tissue for the anabolic effects of AAS, which are mediated by ARs which after exposure to AASs are up-regulated and their number increases with body building. Therefore, AASs determine an increase in muscle size as a consequence of a dose-dependent hypertrophy resulting in an increase of the cross-sectional areas of both type I and type II muscle fibers and myonuclear domains. Moreover, it has been reported that AASs can increase tolerance to exercise by making the muscles more capable to overload therefore shielding them from muscle fiber damage and improving the level of protein synthesis during recovery. Despite some therapeutic use of AASs, there is also wide abuse among athletes especially bodybuilders in order to improve their performances and to increase muscle growth and lean body mass, taking into account the significant anabolic effects of these drugs. The prolonged misuse and abuse of AASs can determine several adverse effects, some of which may be even fatal especially on the cardiovascular system because they may increase the risk of sudden cardiac death (SCD), myocardial infarction, altered serum lipoproteins, and cardiac hypertrophy. The aim of this review is to focus on deaths related to AAS abuse, trying to evaluate the autoptic, histopathological and toxicological findings in order to investigate the pathophysiological mechanism that underlines this type of death, which is still obscure in several aspects. The review of the literature allowed us to identify 19 fatal cases between 1990 and 2012, in which the autopsy excluded in all cases, extracardiac causes of death.