Psychometric and clinical evaluation of schizophrenia remission criteria in outpatients with psychotic disorders

Abstract Background Psychotic disorders such as schizophrenia have debilitating effects on health and functioning. Given symptomatic remission’s recent emergence as a viable treatment goal, the Remission in Schizophrenia Working Group’s criteria (RSWG-cr), based on eight items from the Positive and Negative Syndrome Scale (PANSS-8), are frequently used in clinical and research settings. Against that background, we sought to evaluate the PANSS-8’s psychometric properties and examine the RSWG-cr’s clinical validity among outpatients in Sweden. Methods Cross-sectional register data were collected from outpatient psychosis clinics in Gothenburg, Sweden. Following confirmatory and exploratory factor analyses of PANSS-8 data (n = 1,744) to assess the PANSS-8’s psychometric properties, internal reliability was evaluated using Cronbach’s alpha. Next, 649 of the patients were classified according to the RSWG-cr and their clinical and demographic characteristics compared. Binary logistic regression was used to estimate odds ratios (OR) and assess each variable’s impact on remission status. Results The PANSS-8 showed good reliability (α = .85), and the 3D model of psychoticism, disorganization, and negative symptoms presented the best model fit. According to the RSWG-cr, 55% of the 649 patients were in remission; they were also more likely to live independently, be employed, not smoke, not take antipsychotics, and have recently received a health interview and physical examination. Patients living independently (OR = 1.98), who were employed (OR = 1.89), who were obese (OR = 1.61), and who had recently received a physical examination (OR = 1.56) also had an increased likelihood of remission. Conclusions The PANSS-8 is internally reliable, and, according to the RSWG-cr, remission is associated with variables of interest for patients’ recovery, including living independently and being employed. Although our findings from a large, heterogeneous sample of outpatients reflect everyday clinical practice and reinforce past observations, the directions of those relationships need to be assessed in longitudinal studies

L-Glutamate Biosensor for In Vitro Investigations: Application in Brain Extracts

Investigations of L-glutamate release in living organisms can help to identify novel L-glutamate-related pathophysiological pathways, since abnormal transmission of L-glutamate can cause many neurological diseases. For the first time, a nitrogen-modified graphene oxide (GO) sample (RGO) is prepared through a simple and facile one-pot hydrothermal reduction of GO in the presence of 20 wt.% of the dye malachite green and is used for amperometric biosensing. The biosensor demonstrates adequate stability and is easy to prepare and calibrate. The biosensor detects the current generated during the electrooxidation of hydrogen peroxide released in the L-glutamate that is converted to the alpha-ketoglutarate catalyzed by L-glutamate oxidase. The biosensor consists of a semipermeable membrane, with L-glutamate oxidase (EC 1.4.3.11) immobilized in albumin and RGO and the working Pt electrode. First, the basic version of the L-glutamate biosensor is examined in PBS to investigate its sensitivity, reliability, and stability. To demonstrate the applicability of the L-glutamate biosensor in the analysis of complex real samples, quantification of L-glutamate in bovine brain extract is performed and the accuracy of the biosensor is confirmed by alternative methods. The enhanced version of the L-glutamate biosensor is applied for L-glutamate release investigations in a newly developed strain of rats (DAT-knockout, DAT-KO)