Adenosine A2A receptors control generalization of contextual fear in rats.

Fear learning is essential to survival, but traumatic events may lead to abnormal fear consolidation and overgeneralization, triggering fear responses in safe environments, as occurs in post-traumatic stress disorder (PTSD). Adenosine A2A receptors (A2AR) control emotional memory and fear conditioning, but it is not known if they affect the consolidation and generalization of fear, which was now investigated. We now report that A2AR blockade through systemic administration of the A2AR antagonist SCH58261 immediately after contextual fear conditioning (within the consolidation window), accelerated fear generalization. Conversely, A2AR activation with CGS21680 decreased fear generalization. Ex vivo electrophysiological recordings of field excitatory post-synaptic potentials (fEPSPs) in CA3-CA1 synapses and of population spikes in the lateral amygdala (LA), showed that the effect of SCH58261 is associated with a reversion of fear conditioning-induced decrease of long-term potentiation (LTP) in the dorsal hippocampus (DH) and with increased amplitude of LA LTP in conditioned animals. These data suggest that A2AR are engaged during contextual fear consolidation, controlling long-term potentiation mechanisms in both DH and LA during fear consolidation, impacting on fear generalization; this supports targeting A2AR during fear consolidation to control aberrant fear processing in PTSD and other fear-related disorders.

Medical students' perceptions and motivations during the COVID-19 pandemic.

BACKGROUND: There has been a rapid increase in the number of cases of COVID-19 in Latin America, Africa, Asia and many countries that have an insufficient number of physicians and other health care personnel, and the need for the inclusion of medical students on health teams is a very important issue. It has been recommended that medical students work as volunteers, undergo appropriate training, not undertake any activity beyond their level of competence, and receive continuous supervision and adequate personal protective equipment. However, the motivation of medical students must be evaluated to make volunteering a more evidence-based initiative. The aim of our study was to evaluate the motivation of medical students to be part of health teams to aid in the COVID-19 pandemic. METHODS AND FINDINGS: We developed a questionnaire specifically to evaluate medical students' perceptions about participating in the care of patients with suspected infection with coronavirus during the COVID-19 pandemic. The questionnaire had two parts: a) one part with questions on individual characteristics, year in medical school and geographic location of the medical school and b) a second part with twenty-eight statements assessed on a 5-point Likert scale (totally agree, agree, neither agree nor disagree, disagree and totally disagree). To develop the questionnaire, we performed consensus meetings with a group of faculty and medical students. The questionnaire was sent to student organizations of 257 medical schools in Brazil and answered by 10,433 students. We used multinomial logistic regression models to analyze the data. Statements associated with greater odds ratios for participation of medical students in the COVID-19 pandemic were related to a sense of purpose or duty ("It is the duty of the medical student to put himself or herself at the service of the population in the pandemic"), altruism ("I am willing to take risks by participating in practice in the context of the pandemic"), and perception of good performance and professional identity ("I will be a better health professional for having experienced the pandemic"). Males were more prone than females to believe that only interns should participate in the care of patients with COVID-19 (odds ratio 1.36 [coefficient interval 95%:1.24-1.49]) and that all students should participate (OR 1.68 [CI:1.4-1.91]). CONCLUSIONS: Medical students are more motivated by a sense of purpose or duty, altruism, perception of good performance and values of professionalism than by their interest in learning. These results have implications for the development of volunteering programs and the design of health force policies in the present pandemic and in future health emergencies.

Being fully digital: perspective of a Dutch academic pathology laboratory.

The introduction of fast and robust whole slide scanners has facilitated the implementation of 'digital pathology' with various uses, the final challenge being full digital diagnostics. In this article, we describe the implementation process of a fully digital workflow for primary diagnostics in 2015 at the University Medical Centre in Utrecht, The Netherlands, as one of the first laboratories going fully digital with a future-proof complete digital archive. Furthermore, we evaluated the experience of the first 2 years of working with the system by pathologists and residents. The system was successfully implemented in 6 months, including a European tender procedure. Most pathologists and residents had high confidence in working fully digitally, the expertise areas lagging behind being paediatrics, haematopathology, and neuropathology. Reported limitations concerned recognition of microorganisms and mitoses. Neither the age of respondents nor the number of years of pathology experience was correlated with the confidence level regarding digital diagnostics. The ergonomics of digital diagnostics were better than those of traditional microscopy. In this article, we describe our experiences in implementing our fully digital primary diagnostics workflow, describing in depth the implementation steps undertaken, the interlocking components that are required for a fully functional digital pathology system (laboratory management, hospital information systems, data storage, and whole slide scanners), and the changes required in workflow and slide production.

Newly acquired and reactivated contextual fear memories are more intense and prone to generalize after activation of prelimbic cortex NMDA receptors.

Activity in the rodent prelimbic (PL) cortex contributes to consolidation, retrieval and reconsolidation of learned fear. The PL cortex is considered homologous to the primate dorsal anterior cingulate cortex (dACC). In patients with post-traumatic stress disorder (PTSD), the dACC is often reported to be hyperactive after acquisition and/or around the retrieval of the traumatic memory. It is still unknown, however, whether there is a relationship between altered dACC functioning at these time points and PTSD-associated behavioral outcomes, such as fear overgeneralization. The present study sought to investigate this matter by associating contextual fear conditioning with bilateral and selective activation of PL cortex N-methyl-D-aspartate (NMDA) glutamate receptors with NMDA (0.03-0.3nmol) while the learned fear was being consolidated, retrieved or reconsolidated. We report that this pharmacological intervention induced generalized fear expression and/or extinction deficits in animals subjected to a strong contextual fear conditioning protocol when conducted post-acquisition, pre-retrieval or post-retrieval. These results suggest that newly acquired and reactivated fear memories undergo abnormal consolidation or reconsolidation after PL cortex NMDA receptor activation. The consolidation or reconsolidation of a contextual fear memory trace induced by a weak fear training protocol was also potentiated by PL cortex NMDA receptor activation. Altogether, the present findings connect altered PL cortex activity with changes in specificity and/or intensity of a contextual fear memory, which might shed light on the PTSD neurobiology and related behavioral outcomes.

Alcohol based tissue fixation as an alternative for formaldehyde: influence on immunohistochemistry.

BACKGROUND: Formaldehyde is commonly used in histopathology to fix tissue. Not only are the carcinogenic properties of this solution a hazard to the people in the workplace, it is also a major burden on the environment, and it crosslinks molecular groups that hinder immunohistochemistry. AIMS: The influence of two new alcohol based non-crosslinking fixatives on immunohistochemical staining properties was tested on various tissues. METHODS: Fresh tissue samples were cut into three equal pieces, which were then fixed in the alcohol based fixatives Boonfix or RCL2, or in neutral buffered formaldehyde (NBF) as control. After fixation, tissue was routinely processed to paraffin sections. Deparaffinised slides were blocked for endogenous peroxidase and subsequently submitted to the usual NBF based immunohistochemical protocols for 85 different common antibodies either not requiring antigen retrieval (AR), or AR in citrate buffer, EDTA or pepsin. RESULTS: NBF fixed tissues provided significantly better immunostaining results (84% good staining) than RCL2 (66% good) and Boonfix (60%). The lesser performance of RCL2 and Boonfix was especially caused by pepsin AR which caused significant tissue damage. Omission of pepsin AR resulted in better immunostaining for these antibodies for RCL2 fixed tissues which were overall no longer significantly worse than NBF fixed tissue. CONCLUSION: Tissues fixed in non-crosslinking alcohol based fixatives can successfully be immunohistochemically stained for most antibodies following the usual NBF based protocols. Omission of pepsin pretreatment seems to be important to retain proper morphology of immunostained tissues preserved in alcohol based fixatives. Therefore, when switching to less toxic and non-carcinogenic alcohol-based fixatives like RCL2, no major changes in the daily routine of immunohistochemistry are anticipated.

Antioxidant capacity and phenolic acids of virgin coconut oil.

The antioxidant properties of virgin coconut oil produced through chilling and fermentation were investigated and compared with refined, bleached and deodorized coconut oil. Virgin coconut oil showed better antioxidant capacity than refined, bleached and deodorized coconut oil. The virgin coconut oil produced through the fermentation method had the strongest scavenging effect on 1,1-diphenyl-2-picrylhydrazyl and the highest antioxidant activity based on the beta-carotene-linoleate bleaching method. However, virgin coconut oil obtained through the chilling method had the highest reducing power. The major phenolic acids detected were ferulic acid and p-coumaric acid. Very high correlations were found between the total phenolic content and scavenging activity (r=0.91), and between the total phenolic content and reducing power (r=0.96). There was also a high correlation between total phenolic acids and beta-carotene bleaching activity. The study indicated that the contribution of antioxidant capacity in virgin coconut oil could be due to phenolic compounds.