The fate of quinolizidine alkaloids during the processing of lupins (Lupinus spp.) for human consumption

Lupin, a protein-rich grain legume, and products thereof, are becoming increasingly important in our diets. However, variable and high concentrations of quinolizidine alkaloids (QAs) may hamper this evolution. This study assessed the fate of QAs when processing Lupinus albus seeds and lupin-based foods, to give a first indication of the food industry's ability to sufficiently reduce the QA concentration. Typical unit processes, including toasting, dehulling, sterilization (sterilized jarred lupins), oven baking (cookies), frying (chips) and boiling in water (pasta), were simulated on lab-scale. A quantitative determination of five QAs and qualitative screening of other relevant QAs, in the derived fractions and lupin-based foods, was performed with a validated UHPLC-MS/MS and -HRMS method, respectively. Results revealed that the reduction in quinolizidine alkaloid content is highly dependent on the applied unit process, that QAs appear to be heat stabile, and that the depletion can be attributed to the leaching in cooking water.

A new approach towards biomarker selection in estimation of human exposure to chiral chemicals: a case study of mephedrone

Wastewater-based epidemiology is an innovative approach to estimate public health status using biomarker analysis in wastewater. A new compound detected in wastewater can be a potential biomarker of an emerging trend in public health. However, it is currently difficult to select new biomarkers mainly due to limited human metabolism data. This manuscript presents a new framework, which enables the identification and selection of new biomarkers of human exposure to drugs with scarce or unknown human metabolism data. Mephedrone was targeted to elucidate the assessment of biomarkers for emerging drugs of abuse using a four-step analytical procedure. This framework consists of: (i) identification of possible metabolic biomarkers present in wastewater using an in-vivo study; (ii) verification of chiral signature of the target compound; (iii) confirmation of human metabolic residues in in-vivo/vitro studies and (iv) verification of stability of biomarkers in wastewater. Mephedrone was selected as a suitable biomarker due to its high stability profile in wastewater. Its enantiomeric profiling was studied for the first time in biological and environmental matrices, showing stereoselective metabolism of mephedrone in humans. Further biomarker candidates were also proposed for future investigation: 4′-carboxy-mephedrone, 4′-carboxy-normephedrone, 1-dihydro-mephedrone, 1-dihydro-normephedrone and 4′-hydroxy-normephedrone.

Qualitative screening of new psychoactive substances in pooled urine samples from Belgium and United Kingdom

Concerns about new psychoactive substances (NPS) are increasing due to the rising frequency of serious intoxications. Analysis of biological fluids (urine) is necessary to get reliable information about the use of these substances. However, it is a challenging task due to the lack of analytical standards and the dynamic character of the NPS market. In the present work, a qualitative screening of NPS was carried out in 23 pooled urine samples collected from a city center in the UK and festivals in the UK and Belgium. The analytical method was based on data-independent acquisition mode using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. An in-house library was used with >1500 entries corresponding to NPS, classical drugs and metabolites. All samples contained 53 and 28 compounds of interest from the UK and Belgium respectively. Of the different compounds detected, about 70% were confirmed using retention time and product ions while the remaining compounds were identified using elucidated fragmentation pathways. The highest numbers of NPS identified in both countries were from the cathinone and phenylethylamine families, with a higher number being detected in samples from the festival in the UK. Moreover, several cathinone metabolites in human urine were detected and identified. The screening method proved useful to detect a large number of compounds and determine the use of NPS.

Variation in commercial smoking mixtures containing third-generation synthetic cannabinoids

Variation in ingredients (qualitative variation) and in quantity of active compounds (quantitative variation) in herbal smoking mixtures containing synthetic cannabinoids has been shown for older products. This can be dangerous to the user, as accurate and reproducible dosing is impossible. In this study, 69 packages containing third-generation cannabinoids of seven brands on the UK market in 2014 were analyzed both qualitatively and quantitatively for variation. When comparing the labels to actual active ingredients identified in the sample, only one brand was shown to be correctly labelled. The other six brands contained less, more, or ingredients other than those listed on the label. Only two brands were inconsistent, containing different active ingredients in different samples. Quantitative variation was assessed both within one package and between several packages. Within-package variation was within a 10% range for five of the seven brands, but two brands showed larger variation, up to 25% (Relative Standard Deviation). Variation between packages was significantly higher, with variation up to 38% and maximum concentration up to 2.7 times higher than the minimum concentration. Both qualitative and quantitative variation are common in smoking mixtures and endanger the user, as it is impossible to estimate the dose or to know the compound consumed when smoking commercial mixtures. Copyright © 2016 John Wiley & Sons, Ltd.

Screening for illicit drugs in pooled human urine and urinated soil samples and studies on the stability of urinary excretion products of cocaine, MDMA, and MDEA in wastewater by hyphenated mass spectrometry techniques

Monitoring population drug use through wastewater-based epidemiology (WBE) is a useful method to quantitatively follow trends and estimate total drug consumption in communities. Concentrations of drug biomarkers might be low in wastewater due to dilution; and therefore analysis of pooled urine (PU) is useful to detect consumed drugs and identify targets of illicit drugs use. The aims of the study were (1) to screen PU and urinated soil (US) samples collected at festivals for illicit drug excretion products using hyphenated techniques; (2) to develop and validate a hydrophilic interaction liquid chromatography - mass spectrometry / mass spectrometry (HILIC-MS/MS) method of quantifying urinary targets of identified drugs in wastewater; and (3) to conduct a 24 h stability study, using PU and US to better reflect the chemical environment for targets in wastewater. Cocaine (COC) and ecstasy-like compounds were the most frequently detected illicit drugs; an analytical method was developed to quantify their excretion products. Hydroxymethoxymethamphetamine (HMMA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), HMMA sulfate (HMMA-S), benzoylecgonine (BE), and cocaethylene (CE) had 85-102% of initial concentration after 8 h of incubation, whereas COC and ecgonine methyl ester (EME) had 74 and 67% after 8 h, respectively. HMMA showed a net increase during 24 h of incubation (107% ± 27, n = 8), possibly due to the cleavage of HMMA conjugates, and biotransformation of MDMA. The results suggest HMMA as analytical target for MDMA consumption in WBE, due to its stability in wastewater and its excretion as the main phase I metabolite of MDMA. Copyright © 2016 John Wiley & Sons, Ltd.

Predicting inpatient violence in acute psychiatric wards using the Brøset-Violence-Checklist: a multicentre prospective cohort study

The Norwegian Brøset-Violence-Checklist (BVC) is one of the few instruments that is suitable for short-term prediction of violence of psychiatric inpatients by nursing staff in routine care. The instrument assesses the presence or absence of six behaviours or states frequently observed before a violent incident. We conducted a study to elucidate whether the predictive properties of the BVC are retained in other psychiatric settings than the original north-Norwegian validation dataset. During their admission period, 219 consecutive patients admitted to six acute psychiatric wards were assessed as to the risk for attack using a German version of the BVC (BVC-G). Data on preventive measures were concurrently collected. Aggressive incidents were registered using an instrument equivalent to the Staff Observation of Aggression Scale (SOAS-R). Fourteen attacks towards staff were observed with incident severity ranging from 5 to 18 of a possible 22 points. BVC-G sensitivity was 64.3%, the specificity 93.9%, the positive predictive value 11.1%, and the area under the receiver operating characteristic curve 0.88. In some false positive cases intense preventive measures had been implemented. The predictive accuracy of the BVC-G proved consistent with the Norwegian original.

[A risk profile of the aggressive psychiatric inpatient: can it be identified?]

Violent behavior of psychiatric inpatients has grown in interest. Within the scope of a prospective study,patient assaults in six psychiatric hospitals of the Swiss Canton of Zurich were assessed during a period of 6 months, from November 1999 until May 2000. Three hundred eighty-eight of 5,251 inpatients (7.4%) were reported to act aggressively. The following risk factors for aggressive behavior were identified: male gender, younger age, unemployment, severity of mental illness, and rehospitalization. Psychiatric diagnosis was not related to aggressiveness. In spite of the detection of risk factors, a characteristic profile of aggressive psychiatric inpatients cannot be stated. Research should pay more attention to situation-specific cues for the aggressive behavior of such individuals.

Evidence against differential release of noradrenaline, neuropeptide Y, and dopamine-beta-hydroxylase from adrenergic nerves in the isolated perfused sheep spleen

The subcellular storage and release of noradrenaline (NA), dopamine-beta-hydroxylase (D beta H), and neuropeptide Y (NPY) was studied in the isolated perfused sheep spleen. Subcellular distribution studies showed a bimodal distribution for NA which was well reflected by D beta H and indicated the occurrence of two types of NA storage vesicles. The most dense, presumably large dense-cored vesicles (LDV), contain both membrane-bound and soluble D beta H; the less dense presumably corresponds to small dense-cored vesicles (SDV) and at least does not contain soluble D beta H. The distribution of NPY is extended but shows a peak only at the position of LDV, indicating that LDV contain NPY. Continuous electrical stimulation of the splenic nerve at 2 Hz, 5 Hz, 10 Hz, and 20 Hz or at 20 hz with bursts induced the release of NA, NPY, and D beta H. The ratio among these components was constant. The fractional release of D beta H and NA was comparable at all frequencies used; that of NPY was 10-20 times lower, suggesting the occurrence of a large nonreleasable NPY pool. The present data argue against a high frequency stimulation or intermittent stimulation-induced preferential release of NPY from adrenergic neurons and question the concept of frequency-dependent chemical coding of sympathetic transmission in general. The simplest interpretation of our data is that NA and NPY are released at all frequencies from a single pool. The present finding might signify that only large dense-cored vesicles are involved in the sympathetic stimulation-evoked secretion of catecholamines from adrenergic nerve terminals of the isolated sheep spleen.

Ultrastructural localization of neuropeptide Y-immunoreactivity in the axonal reticulum elements, accumulating anterogradely in transected rat sciatic nerve

The detection of dopamine-beta-hydroxylase and cytochrome B561 on the membranes of the axonal reticulum demonstrated that in sympathetic neurons the different compartments of the axonal reticulum participate in the formation of neurosecretory vesicles. In the present study we tried to reveal that the components of the vesicular content are also channeled along the axonal reticulum, by examining whether neuropeptide Y could be localized in elements of the axonal reticulum. Therefore 6 h transected rat sciatic nerve was embedded in glycolmethacrylate and an immunogold labeling was performed. Counterstaining with phosphotungstic acid at low pH selectively contrasted the accumulated axonal reticulum elements and associated granules. In the non-myelinated axons gold labeling was localized on granules and on tubular and granular profiles, demonstrating the presence of neuropeptide Y in the accumulated axonal reticulum elements. This indicates that neuropeptides are indeed transported via the axonal reticulum to the nerve ending and suggests that the accumulation of large dense-cored vesicles at a block is mainly due to local new formation rather than down transport.

Posttranslational processing of proenkephalins and chromogranins/secretogranins

Posttranslational processing of peptide-precursors is nowadays believed to play an important role in the functioning of neurons and endocrine cells. Both proenkephalins and chromogranins/secretogranins are considered as precursor molecules in these tissues, resulting in posttranslationally formed degradation products with potential biological activities. Among the proteins and peptides of neuronal and endocrine secretory granules, the enkephalins and enkephalin-containing peptides have been most extensively studied. The characterization of the post-translationally formed degradation products of the proenkephalins have enabled the understanding of their processing pathway. Chromogranins/secretogranins represent a group of acidic glycoproteins, contained within hormone storage granules. The biochemistry, biogenesis and molecular properties of these proteins have already been studied for 25 years. The chromogranins/secretogranins have a widespread distribution throughout the neuroendocrine system, the adrenal medullary chromaffin granules being the major source of these storage components. Recent data provide evidence for a precursor role for all members of the chromogranins/secretogranins family although also several other functions have been proposed. In this review, some of the methods applied to study proteolytic processing are described. In addition, the posttranslational processing of chromogranins/secretogranins and proenkephalins, especially the biochemical aspects, will be discussed and compared. Recent exciting developments on the generation and identification of potential physiologically active fragments will be covered.

Chromogranin A processing in sympathetic neurons and release of chromogranin A fragments from sheep spleen

Chromogranin A (CGA) has been localized to the large dense cored vesicles (LDV) of sympathetic neurons. SDS-PAGE and immunoblotting of soluble LDV proteins from ox and dog adrenergic neuronal cell bodies, axons and nerve terminals, revealed an increasing number of CGA-immunoreactive forms, consistent with proteolytic processing during axonal transport. Splenic nerve electrical stimulation (10 Hz, 2 min) revealed that, apart from CGA, these CGA-processing products are released from the sheep spleen. The secretion of CGA-derived fragments from sympathetic neurons might suggest a role in the regulation of synaptic transmission.

Preparation of noradrenaline-storing organelles from bovine sympathetic ganglia: biochemical and morphological evaluation of partly purified large dense cored vesicles

Large dense cored vesicles from bovine sympathetic ganglia were isolated and partly purified. Biochemical and morphological evaluation of the present vesicle-preparation revealed that it represents a convenient fraction for the characterization of perikaryal noradrenergic vesicles. Homogenates of bovine stellate ganglia were subjected to differential centrifugation and D2O-sucrose density gradient centrifugation. Biochemical evaluation of gradient fractions was performed by measuring marker enzyme activities reflecting subcellular contamination, while morphological evaluation was performed by electron microscopic analysis of the isolated fractions. Both techniques revealed that the vesicle-preparation was, at first, still considerably contaminated by mitochondria and lysosomes. An improved purification could be achieved by subjecting this fraction to an additional centrifugation under iso-osmotic conditions, also applied for the preparation of highly purified splenic nerve vesicles. The resulting vesicle-fraction was almost completely free of contaminating enzyme activities and consisted merely of large dense cored vesicles as revealed by electron microscopic observations (50-70% purity). Neuropeptide Y and chromogranin A were enriched more than 50 times as compared to the total homogenate. Although the purity of these vesicles was still not satisfactory for direct chemical analysis, this vesicle-preparation seemed very well suited for immunological characterization of perikaryal large dense cored vesicles.

The presence of phospholipase A2 in bovine adrenal medulla: arguments for more than one type of phospholipase A2

Since phospholipase A2 (PLA2) is expected to play a role in the mechanism of exocytosis, the presence and subcellular localization of PLA2 in bovine adrenal medulla have been studied. The results of this study reveal that, although a large part of the PLA2 activity in chromaffin cells is due to a lysosomal PLA2, a cytoplasmic PLA2 is also present. This finding is supported by experiments in which the influence of pH, CaCl2 and NaCl on cytoplasmic PLA2 as well as the binding capacity to concanavalin A are investigated. According to these results the properties of a cytoplasmic PLA2 are clearly different from those reported by other authors for the lysosomal PLA2. For this reason, in chromaffin cells a PLA2 could be present which remains in the cytosol when the cell is in rest. Future experiments will have to prove whether this PLA2 becomes associated with the plasma membrane upon stimulation of the cell, thus mediating exocytosis.

Subcellular fractionation of bovine ganglion stellatum: co-storage of noradrenaline, Met-enkephalin and neuropeptide Y in large 'dense-cored' vesicles

The subcellular localization of noradrenaline, Met-enkephalin and neuropeptide Y was studied in homogenates of bovine ganglion stellatum. After differential centrifugation most of the noradrenaline (70%) was found soluble, while both neuropeptide Y and Met-enkephalin were sedimented for more than 65%. However, the 3 substances co-sedimented mainly in the microsomal fraction. The microsomal fraction was further analyzed by differential and equilibrium density gradient centrifugation. In both types of gradient, Met-enkephalin and neuropeptide Y were found in the more dense region of the gradient, coinciding with the main peak of noradrenaline. In this fraction, the molar ratio of Met-enkephalin to noradrenaline was 1:95. The corresponding molar ratio for neuropeptide Y to noradrenaline was 1:253. These results indicate that neuropeptide Y and Met-enkephalin are stored with noradrenaline in 'heavy' or large 'dense cored' vesicles in the cell bodies of sympathetic neurons of bovine ganglion stellatum. We present here for the first time biochemical evidence for the co-localization of neuropeptides and a classical transmitter in a neuronal cell body.