Alzheimer's disease (AD) is a severe neurodegenerative disorder still in search of effective methods of diagnosis. Altered levels of the NMDA receptor co-agonist, d-serine, have been associated with neurological disorders, including schizophrenia and epilepsy. However, whether d-serine levels are deregulated in AD remains elusive. Here, we first measured D-serine levels in post-mortem hippocampal and cortical samples from nondemented subjects (n=8) and AD patients (n=14). We next determined d-serine levels in experimental models of AD, including wild-type rats and mice that received intracerebroventricular injections of amyloid-β oligomers, and APP/PS1 transgenic mice. Finally, we assessed d-serine levels in the cerebrospinal fluid (CSF) of 21 patients with a diagnosis of probable AD, as compared with patients with normal pressure hydrocephalus (n=9), major depression (n=9) and healthy controls (n=10), and results were contrasted with CSF amyloid-β/tau AD biomarkers. d-serine levels were higher in the hippocampus and parietal cortex of AD patients than in control subjects. Levels of both d-serine and serine racemase, the enzyme responsible for d-serine production, were elevated in experimental models of AD. Significantly, d-serine levels were higher in the CSF of probable AD patients than in non-cognitively impaired subject groups. Combining d-serine levels to the amyloid/tau index remarkably increased the sensitivity and specificity of diagnosis of probable AD in our cohort. Our results show that increased brain and CSF d-serine levels are associated with AD. CSF d-serine levels discriminated between nondemented and AD patients in our cohort and might constitute a novel candidate biomarker for early AD diagnosis.

Recent evidence suggests that Alzheimer's disease (AD) and depression share common mechanisms of pathogenesis. In particular, deregulation of glutamate-mediated excitatory signaling may play a role in brain dysfunction in both AD and depression. We have investigated levels of glutamate and its precursor glutamine in the cerebrospinal fluid (CSF) of patients with a diagnosis of probable AD or major depression compared to healthy controls and patients with hydrocephalus. Patients with probable AD or major depression showed significantly increased CSF levels of glutamate and glutamine compared to healthy controls or hydrocephalus patients. Furthermore, CSF glutamate and glutamine levels were inversely correlated to the amyloid tau index, a biomarker for AD. Results suggest that glutamate and glutamine should be further explored as potential CSF biomarkers for AD and depression.

CSF Aβ42, T-tau, and P-tau levels may differentiate between AD and depression in a Brazilian sample.

This study objective was to investigate publication trends on personality disorders (PD) and to identify patterns of historical development. Publication rates were determined using the Results by Year Timeline feature of PubMed. Time series autoregressive integrated moving average models were used to analyse the publication rates for PDs in quinquennial periods beginning in 1980 and ending in 2019 and to predict the number of publications in the 2024-2029 period. More than 300 articles on antisocial and borderline PD are being published each year, and the models suggest an accelerating growth rate. Approximately 100 articles are being published on average every year on schizotypal PD, and the regression model indicates linear growth in the near future. The mean number of publications per year for obsessive-compulsive, narcissistic and avoidant PDs is in the range of 10-30 with the corresponding models indicating linear growth. Fewer than 10 articles are being published each year on dependent, paranoid, histrionic and schizoid PD, whereas dependent PD shows modest growth and paranoid PD rates tended to stability, histrionic and schizoid PD exhibit declining rates. Personality disorders are a group of conditions with diverse etiological, prognostic, therapeutic, legal, research, social and cultural implications that influence publication rates.

Objective: Bibliometrics is a group of statistical and mathematical methods employed to measure and analyze the quantity and the quality of scientific articles, books, and other forms of publications. The objective of the present study was to conduct a bibliometric analysis of the Jornal Brasileiro de Psiquiatria (JBP) by listing its 100 most highly cited articles in the scientific literature and identifying their main characteristics in terms of authorship and research topics and design. Methods: The 100 top-cited references in the JBP were identified through a search with Google Scholar. The main author, last author, corresponding author, the total number of authors, gender of the authors, year of publication, research institution, geographic origin, language, and the research design and subject of each reference were recorded and analyzed. Results: A marked increase in the number of citations in the last 15 years, a relatively balanced distribution of publications among the Brazilian states and research centers, absence of gender bias among authors, and a varied range of published topics suggest a good current editorial performance by the JBP. Relative lack of systematic reviews and longitudinal studies, dearth of articles published in the English language, and modest participation of foreign authors were points requiring improvement. Conclusion: The present study suggests that a survey of the 100 most cited articles in the JBP can provide a historical overview of the progress of this journal, as well as highlight the main obstacles, constraints, and challenges faced by its editors and authors.