Stronger tilt aftereffects in individuals diagnosed with schizophrenia spectrum disorders but not bipolar disorder.

An altered use of context and experience to interpret incoming information has been posited to explain schizophrenia symptoms. The visual system can serve as a model system for examining how context and experience guide perception and the neural mechanisms underlying putative alterations. The influence of prior experience on current perception is evident in visual aftereffects, the perception of the "opposite" of a previously viewed stimulus. Aftereffects are associated with neural adaptation and concomitant change in strength of lateral inhibitory connections in visually responsive neurons. In a previous study, we observed stronger aftereffects related to orientation (tilt aftereffects) but not luminance (negative afterimages) in individuals diagnosed with schizophrenia, which we interpreted as potentially suggesting altered cortical (but not subcortical) adaptability and local changes in excitatory-inhibitory interactions. Here, we tested whether stronger tilt aftereffects were specific to individuals with schizophrenia or extended to individuals with bipolar disorder. We measured tilt aftereffects and negative afterimages in 32 individuals with bipolar disorder, and compared aftereffect strength to a previously reported group of 36 individuals with schizophrenia and 22 healthy controls. We observed stronger tilt aftereffects, but not negative afterimages, in individuals with schizophrenia as compared to both controls and individuals with bipolar disorder, who did not differ from each other. These results mitigate concerns that stronger tilt aftereffects in schizophrenia are a consequence of medication or of the psychosocial consequences of a severe mental illness.

Abnormal Oculomotor Corollary Discharge Signaling as a Trans-diagnostic Mechanism of Psychosis.

BACKGROUND AND HYPOTHESIS: Corollary discharge (CD) signals are "copies" of motor signals sent to sensory areas to predict the corresponding input. They are a posited mechanism enabling one to distinguish actions generated by oneself vs external forces. Consequently, altered CD is a hypothesized mechanism for agency disturbances in psychosis. Previous studies have shown a decreased influence of CD signals on visual perception in individuals with schizophrenia-particularly in those with more severe positive symptoms. We therefore hypothesized that altered CD may be a trans-diagnostic mechanism of psychosis. STUDY DESIGN: We examined oculomotor CD (using the blanking task) in 49 participants with schizophrenia or schizoaffective disorder (SZ), 36 bipolar participants with psychosis (BPP), and 40 healthy controls (HC). Participants made a saccade to a visual target. Upon saccade initiation, the target disappeared and reappeared at a horizontally displaced position. Participants indicated the direction of displacement. With intact CD, participants can make accurate perceptual judgements. Otherwise, participants may use saccade landing site as a proxy of pre-saccadic target to inform perception. Thus, multi-level modeling was used to examine the influence of target displacement and saccade landing site on displacement judgements. STUDY RESULTS: SZ and BPP were equally less sensitive to target displacement than HC. Moreover, regardless of diagnosis, SZ and BPP with more severe positive symptoms were more likely to rely on saccade landing site. CONCLUSIONS: These results suggest that altered CD may be a trans-diagnostic mechanism of psychosis.

Associations between N-Acetylaspartate and white matter integrity in individuals with schizophrenia and unaffected relatives.

Compromised white matter has been reported in schizophrenia; however, few studies have investigated neurochemical abnormalities underlying microstructural differences. N-acetylaspartate (NAA) is used to synthesize myelin and is often reduced in persons with schizophrenia (PSZ) and their unaffected first-degree relatives (REL). Low levels of NAA could affect white matter by preventing the synthesis or repair of myelin. We used magnetic resonance spectroscopy and diffusion tensor imaging to investigate the relationship between NAA and white matter integrity in PSZ. REL were included to examine whether putative relationships are associated with symptom expression or illness liability. 52 controls, 23 REL and 25 PSZ underwent 7T proton magnetic resonance spectroscopy and/or 3T diffusion tensor imaging. NAA in the visual cortex and basal ganglia were measured and compared across groups. Diffusivity measures were compared across groups using tract-based spatial statistics and related to NAA concentrations. Visual cortex NAA was significantly reduced in PSZ compared to controls. White matter integrity did not differ between groups. Reduced cortical and subcortical NAA were associated with diffusivity measures of poor white matter microstructure. These data suggest that levels of neural NAA may be related to white matter integrity similarly across individuals with schizophrenia, those at genetic risk, and controls.

Variables influencing conditioning-evoked hallucinations: overview and future applications.

Hallucinations occur in the absence of sensory stimulation and result in vivid perceptual experiences of nonexistent events that manifest across a range of sensory modalities. Approaches from the field of experimental and cognitive psychology have leveraged the idea that associative learning experiences can evoke conditioning-induced hallucinations in both animals and humans. In this review, we describe classical and contemporary findings and highlight the variables eliciting these experiences. We also provide an overview of the neurobiological mechanisms, along with the associative and computational factors that may explain hallucinations that are generated by representation-mediated conditioning phenomena. Through the integration of animal and human research, significant advances into the psychobiology of hallucinations are possible, which may ultimately translate to more effective clinical applications.

Psychosis in transgender and gender non-conforming individuals: A review of the literature and a call for more research.

Epidemiological studies have described higher rates of psychotic disorder diagnoses in transgender, as compared to cisgender, individuals. With the exception of this work and a small number of published case studies, however, there has been little consideration of gender diversity in psychosis research or clinical care. In this paper, we will review and critically evaluate the limited literature on gender diversity and clinical psychosis and articulate the critical need for more work in this field, more specifically on the following areas and how they bear on clinical care: 1) diagnostic biases; 2) how chronic non-affirmation and bias, gender dysphoria, and other gender minority stressors may operate as trauma and can contribute to clinically significant psychotic symptoms; 3) the potential impact of gender-affirming care, such as hormone therapies, on mental health and barriers for receiving such care in transgender and nonbinary individuals; and 4) culturally-sensitive and gender-affirming approaches for addressing psychosis. Finally, we consider ways in which researchers may engage in ethical, gender-affirming, and accurate approaches to better address gender identity in psychosis research. We hope that such research will aid in the creation of clinical guidelines for understanding, diagnosing, and treating psychosis in gender diverse individuals.

Frontal cortex dysfunction as a target for remediation in opiate use disorder: Role in cognitive dysfunction and disordered reward systems.

In this chapter, we develop a model of µ- and δ-opioid receptor (OR) effects on cellular activity in the corticostriatal circuit after reviewing clinical data on cognitive and mood impairments in opioid substance use disorder (OUD), we use this model to derive information on the relevance of opioid actions in this circuit for cognition and reward. We find that the cognitive impairments and rewarding properties of acute µ-OR activation can reasonably explained by pharmacological actions in the corticostriatal circuit. However, long-term cognitive impairments and mood dysfunction observed in OUD are probably induced by opiate abuse-related degenerative mechanisms.

Large-Scale Assessment of Extractables and Leachables in Single-Use Bags for Biomanufacturing.

Single-use technologies (SUTs) are widely used during biopharmaceutical manufacture as disposable bioreactors or media and buffer storage bags. Despite their advantages, the risk of release of extractable and leachable (E&Ls) substances is considered an important drawback in adopting disposables in the biomanufacturing process. E&Ls may detrimentally affect cell viability or productivity or may persist during purification and present a risk to the patient if remaining in the final drug product. In this study, 34 plastic films from single-use bags (SUBs) for cell cultivation were extracted with selected solvents that represent reasonable worst-case conditions for most typical biomanufacturing applications. SUBs were incubated at small-scale under accelerated-aging conditions that represented standard operational conditions of use. Leachables analysis was performed following dispersive liquid-liquid microextraction (DLLME) for analyte preconcentration and removal of matrix interference. Resulting extracts were characterized by GC-headspace for volatiles, high resolution GC-Orbitrap-MS/MS for semivolatiles, high resolution LC-Orbitrap-MS/MS for nonvolatiles, and ICP-MS for trace elemental analysis. Multivariate statistical analysis of the analytical data revealed significant correlations between the type and concentration of compounds and bags features including brand, manufacturing date and polymer type. The analytical data demonstrates that, over recent years, the nature of E&Ls has been altered due to the implementation of manufacturing changes and new types of polymers and may change further with the future advent of regulations that will limit or ban the use of certain raw materials and additives. The broad E&L database generated herein facilitates toxicological assessments from a biomanufacturing standpoint and provides practical guidelines for confident determination of E&Ls to enable screening and elimination of nonsatisfactory films for single use bioprocessing.

Meeting the European Commission performance criteria for the use of triple quadrupole GC-MS/MS as a confirmatory method for PCDD/Fs and dl-PCBs in food and feed samples.

Until recently, European Union (EU) legislation required the use of high-resolution gas chromatography coupled to high-resolution mass spectrometry (HRGC-HRMS) based on magnetic sector analyzers as a standard approach for confirmatory analysis of dioxins (PCDDs) and furans (PCDFs) in feed and food. However, recent technological advances in MS instruments enabled other alternative analytical techniques to meet the same analytical criteria as those requested for HRGC-HRMS. In this sense, triple quadrupoles (GC-MS/MS) can be a realistic alternative for the analysis of dioxins. In this work, the performance of GC-MS/MS technology was evaluated against the criteria demanded by the EU for confirmatory analysis of dioxins and PCBs in food and feed. Thus, the study comprises a number of parameters including chromatographic separation, limit of quantification, linearity, repeatability, and ion ratio precision. Analyses of solvent standards as well as sample extracts (inter-calibration extracts and certified reference materials) were also considered within the scope of this study. Additionally, direct comparisons of the results obtained by GC-MS/MS with those from GC-HRMS were made. The results of this work suggested that GC-MS/MS was highly sensitive and selective for confirmatory analysis of PCDD/Fs and related compounds in food and feed samples and meets all the criteria requested by the European Commission.

Use of atmospheric pressure solids analysis probe time-of-flight mass spectrometry to screen for plasticisers in gaskets used in contact with foods.

RATIONALE: Plasticisers are used in the PVC gaskets of metal closures on glass jars and bottles used for foods and beverages. They may migrate and so contaminate the packed foodstuff. The plasticisers are present in a high proportion and are often a complex mixture of substances leading to time-consuming analytical methodologies. This work describes a rapid screening method to identify the plasticisers used. METHODS: Analysis was carried out by direct sampling of the gaskets using atmospheric pressure solids analysis probe (ASAP) with time-of-flight (TOF) mass spectrometry (MS) using a SYNAPT G2 HDMS system. The accurate mass information collected was then compared to a user-prepared database of plasticisers to aid identification. RESULTS: The rapid identification approach was shown to be successful for 24 gasket samples previously analysed by alternative more lengthy gas chromatographic (GC) methods. Quantification by dissolution followed by standard addition was also demonstrated to be reliable. CONCLUSIONS: The ASAP-TOFMS method is a useful technique for rapidly screening gaskets for the presence of plasticisers. It can be used to identify specific gaskets deserving of further quantitative analysis by chromatographic methods, saving time and money by avoiding unnecessary analyses. Copyright © 2015 John Wiley & Sons, Ltd.

Evaluation and validation of an accurate mass screening method for the analysis of pesticides in fruits and vegetables using liquid chromatography-quadrupole-time of flight-mass spectrometry with automated detection.

This study reports the development and validation of a screening method for the detection of pesticides in 11 different fruit and vegetable commodities. The method was based on ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-QTOF-MS). The objective was to validate the method in accordance with the SANCO guidance document (12571/2013) on analytical quality control and validation procedures for pesticide residues analysis in food and feed. Samples were spiked with 199 pesticides, each at two different concentrations (0.01 and 0.05 mg kg(-1)) and extracted using the QuEChERS approach. Extracts were analysed by UPLC-QTOF-MS using generic acquisition parameters. Automated detection and data filtering were performed using the UNIFI™ software and the peaks detected evaluated against a proprietary scientific library containing information for 504 pesticides. The results obtained using different data processing parameters were evaluated for 4378 pesticide/commodities combinations at 0.01 and 0.05 mg kg(-1). Using mass accuracy (± 5 ppm) with retention time (± 0.2 min) and a low response threshold (100 counts) the validated Screening Detection Limits (SDLs) were 0.01 mg kg(-1) and 0.05 mg kg(-1) for 57% and 79% of the compounds tested, respectively, with an average of 10 false detects per sample analysis. Excluding the most complex matrices (onion and leek) the detection rates increased to 69% and 87%, respectively. The use of additional parameters such as isotopic pattern and fragmentation information further reduced the number of false detects but compromised the detection rates, particularly at lower residue concentrations. The challenges associated with the validation and subsequent implementation of a pesticide multi-residue screening method are also discussed.

Investigation of the human brain metabolome to identify potential markers for early diagnosis and therapeutic targets of Alzheimer's disease.

A study combining high resolution mass spectrometry (liquid chromatography-quadrupole time-of-flight-mass spectrometry, UPLC-QTof-MS) and chemometrics for the analysis of post-mortem brain tissue from subjects with Alzheimer's disease (AD) (n = 15) and healthy age-matched controls (n = 15) was undertaken. The huge potential of this metabolomics approach for distinguishing AD cases is underlined by the correct prediction of disease status in 94-97% of cases. Predictive power was confirmed in a blind test set of 60 samples, reaching 100% diagnostic accuracy. The approach also indicated compounds significantly altered in concentration following the onset of human AD. Using orthogonal partial least-squares discriminant analysis (OPLS-DA), a multivariate model was created for both modes of acquisition explaining the maximum amount of variation between sample groups (Positive Mode-R2 = 97%; Q2 = 93%; root mean squared error of validation (RMSEV) = 13%; Negative Mode-R2 = 99%; Q2 = 92%; RMSEV = 15%). In brain extracts, 1264 and 1457 ions of interest were detected for the different modes of acquisition (positive and negative, respectively). Incorporation of gender into the model increased predictive accuracy and decreased RMSEV values. High resolution UPLC-QTof-MS has not previously been employed to biochemically profile post-mortem brain tissue, and the novel methods described and validated herein prove its potential for making new discoveries related to the etiology, pathophysiology, and treatment of degenerative brain disorders.

Development and single-laboratory validation of an HPLC method for the determination of in foodstuffs using internal standardization and solid-phase extraction cleanup.

A selective, sensitive and rapid procedure based on liquid chromatography with photodiode array detection (HPLC-PDA) has been developed, single laboratory validated and cross-validated by an external laboratory for the determination of coumarin, a naturally occurring biologically active principle, in a range of foods and beverages. Reverse phase solid-phase extraction (SPE) was used to clean sample extracts when co-extractives were found to interfere with detection and the presence of coumarin was confirmed by comparison of chromatographic peak UV spectra with coumarin standards and quantified by the use of an internal standard. The method was applied to the analysis of flour products, breakfast cereal, gelatin confectionery, sugar confectionery, rice pudding, mixed spice, camomile infusion and soft drinks. Coumarin could not be confirmed in extracts of camomile infusions due to the presence of co-eluting peaks as confirmed by UV spectral analysis. Chromatographic separation was achieved on an octadecyl (C8) column using a mobile phase gradient of acetonitrile and 0.5% acetic acid with a total run time of 20 minutes. The limits of detection and quantification were sample dependent and ranged from 0.05 to 2.5 mg kg-1 and 0.05 to 8 mg kg-1 respectively. The method was successfully validated to show the standard range linearity, sensitivity, accuracy and precision in the matrices tested. Coumarin is regulated within the European Union so this method may be readily adapted for enforcement purposes.

Inactivation of the complement anaphylatoxin C5a by secreted products of parasitic nematodes.

Given the importance of the complement anaphylatoxins in cellular recruitment during infection, the ability of secreted products from larval stages of Brugia malayi and Trichinella spiralis to influence C5a-mediated chemotaxis of human peripheral blood granulocytes in vitro was examined. Secreted products from B. malayi microfilariae almost completely abolished chemotaxis. This inhibition was blocked by phenylmethylsulphonyl fluoride, indicating the presence of a serine protease, which was subsequently shown to cleave C5a. In contrast, secreted products from T. spiralis infective larvae showed modest inhibition of C5a-mediated granulocyte chemotaxis, and this was blocked by potato carboxypeptidase inhibitor, an inhibitor of several metallocarboxypeptidases. Adult and larval stages of both parasites were demonstrated to secrete carboxypeptidases which cleaved hippuryl-L-lysine and hippuryl-L-arginine, and the T. spiralis enzyme was partially characterised. The data are discussed with reference to inflammation in parasitic nematode infection.

Survey of furan in foods and coffees from five European Union countries.

Canned and jarred baby foods (74), canned and jarred adult foods (63) and 70 coffees sold in Belgium, Italy, Portugal, Spain and The Netherlands were analysed for their furan content using a validated automated headspace GC-MS procedure. Seven balsamic vinegars from Italy and Spain were also analysed. All 74 baby food samples contained detectable furan, with an average level of 37 ng/g. A total of 54 of 63 canned and jarred foods contained detectable furan with an average level of 24 ng/g. Levels of furan in coffee as consumed were very variable and reflected different preparation methods and coffee strengths. Over 50% of Italian samples contained more than 200 ng/g, whereas over 20% of Belgian coffees contained less than 21 ng/g furan. Some brews made from fine grained coffee contained much more furan than did brews made from normal or coarse grained coffee. Although furan was low in most instant coffees, two Italian products "instant espresso" and "instant mocha" contained about 150 ng/g furan. Balsamic vinegars from Spain contained 159-662 ng/g of furan; however, other samples from Spain and Italy contained only 6-25 ng/g.

Development and validation of a rapid headspace gas chromatography-mass spectrometry method for the determination of diethyl ether and acetone residues in Tween extracts of shellfish intended for mouse bioassay for diarrhoetic toxins.

A validated analytical method using headspace capillary gas chromatography with mass spectrometric detection, which utilises deuterated analogues of the target analytes as internal standards has been developed and applied to the determination of acetone and diethyl ether in Tween extracts of cockles (Cerastoderma edule) and mussels (Mytilus edulis) destined for mouse bioassay for lipophilic toxins. The optimal conditions for headspace incubation were 50 degrees C for 6 min. The limits of detection and quantitation for both DEE and acetone were 2 and 7 microg/mL, respectively, based on signal to noise ratios of 3 and 10, respectively. The linear dynamic range of the instrument was 0 to ca. 4000 microg/mL for both acetone (r(2)=0.995) and DEE (r(2)=0.999). Tween extracts of cockle spiked with acetone and DEE at 3925 and 3570 microg/mL, respectively, gave mean (n=3) recovery figures of 101% (RSD=13.1%) for acetone and 90% (RSD=7.3%) for DEE in cockle matrix. The corresponding figures obtained from spiked mussel matrix were 114% (RSD=5.7%) for acetone and 95% (RSD=6.7%) for DEE, respectively, which were within acceptable range.

Method development and HPLC analysis of retail foods and beverages for copper chlorophyll (E141[i]) and chlorophyllin (E141[ii]) food colouring materials.

An analytical method using high performance liquid chromatography with photodiode array and fluorescence detection has been developed and applied to the determination of the food colour additives copper chlorophylls and copper chlorophyllins (E141[i] and [ii]) in foods and beverages. The analytical procedures from previously reported methods have been refined to cover a range of food colour formulations and retail foods. The method was single-laboratory validated. Recoveries of the polar copper chlorophyllins from spiked samples (at 14.5 mg/kg in all but one case) were in the range 79-109%, except for jelly sweets (49%). Recoveries of relatively non-polar copper chlorophylls were in the range 77-107% (except for 'made' jelly at 50%). The %RSD for recoveries was generally below 12%. Quantitative estimates of the total copper chlorophyll/chlorophyllin content of a small range of food commodities are reported, based on the use of trisodium copper chlorophyllin as a surrogate standard. The majority of E141-containing foods and colour formulations analysed exhibited a multiplicity of components due to the various extraction and purification processes that are used to obtain these colour additives. This was confounded by the presence of overwhelming amounts of native chlorophylls in certain samples (e.g. mint sauce). Food commodities containing significant amounts of emulsifiers (i.e. ice cream), gelatine or fats were problematic during extraction hence further development of extraction regimes is desirable for such products. All of the samples analysed with added E141, had estimated total copper chlorophyllin contents of below 15 mg/kg (range 0.7-13.0).