Reduced inhibitory action of a GABA(B )receptor agonist on [(3)H]-dopamine release from rat ventral tegmental area in vitro after chronic nicotine administration

BACKGROUND: The activation of GABA(B )receptors in the ventral tegmental area (VTA) has been suggested to attenuate the rewarding properties of psychostimulants, including nicotine. However, the neurochemical mechanism that underlie this effect remains unknown. Since GABA(B )receptors modulate the release of several neurotransmitters in the mammalian brain, we have characterised the effect of the GABA(B )receptor agonist baclofen on the release of [(3)H]-dopamine ([(3)H]-DA) from VTA slices of naïve rats and of rats pre-treated with nicotine. RESULTS: In naïve rats, baclofen concentration-dependently inhibited the electrically evoked release of [(3)H]-DA from the isolated VTA (EC(50 )= 0.103 μM, 95% CI = 0.043–0.249), without affecting the basal [(3)H]-monoamine overflow. This effect was mediated by activation of GABA(B )receptors as it was blocked by the selective receptor antagonist CGP55845A. Chronic administration of nicotine (0.4 mg kg(-1), s.c., for 14 days) affected neither the basal nor the electrically evoked release of [(3)H]-DA from VTA slices. However, the inhibitory effect of baclofen (10 μM) on the stimulated [(3)H]-monoamine overflow was abolished in rats pre-treated with nicotine as compared to saline-injected controls. CONCLUSIONS: Our results demonstrate that GABA(B )receptor activation reduces the release of DA from the rat VTA. In addition, a reduced sensitivity of VTA GABA(B )receptors appears to develop after chronic exposure to nicotine. The resulting disinhibition of VTA DA neurones might therefore contribute to the sensitised dopaminergic responses observed in the rat mesocorticolimbic system following repeated administration of nicotine

In vitro comparative study on the mechanical behavior of Zirconia and Polyetheretherketone in applied dental sciences

OBJECTIVE: Recently, Zirconia and polyaryletherketone (PEEK) have attracted increasing interest as reliable and safe materials in dental applications, mainly because of their good biomechanical characteristics. The aim of this study was to investigate the response to different loads by prosthetic frameworks for supported fixed partial dentures (FPDs), thus simulating osseointegrated implants. MATERIALS AND METHODS: The specimens were divided into two groups (n= 5 each). Group A: FDPs in zirconia-ceramic; Group B: FDPs in PEEK-composite. These 2 groups were subjected to vertical loads so to evaluate structural deformation; then, they have been analyzed by scanning electron microscopy (SEM) at different magnifications. RESULTS: In tested samples, different types of mechanical failures have been observed. In Zirconia-specimens, chipping is the main failure noticed in this study, mostly in distal margins of the structure. Also, peek-specimens show failure and fracture. CONCLUSIONS: Zirconia and PEEK could be considered both good materials, but several investigations are needed to use these materials as an alternative to metals for fixed partial dentures

A new tool to evaluate burnout: the Italian version of the BAT for Italian healthcare workers

Background: Healthcare workers (HCWs) represents one of the highest-risk population to develop burnout symptoms. Recently, a new tool has been designed to measure several dimensions that capture an exhaustive expression of burnout symptoms by six dimensions (i.e., exhaustion; mental distance; cognitive impairment; emotional impairment; psychological distress; psychosomatic complaints). Methods: The current study aims to adapt the Burnout Assessment Tool (BAT) to an Italian Healthcare workers’ sample confirming the original second-order factorial structure. Furthermore, we expected to find good indexes of reliability and validity tests. Participants were 697 Italian Health Care Workers (Female = 68.44%; mean age = 36.47; SD = 11.20). Data were collected by self-report questionnaires submitted by the snowball method. Results: Findings show a good fit of the BAT’s structure, confirming the hypothesized second-order factorial model. Furthermore, good reliability has been established with the study’s measures. Conclusions: The BAT for HCWs is eligible as a new tool to evaluate burnout in the at-risk HCWs as a multi-facet constellation of symptoms

Multicentre translational Trial of Remote Ischaemic Conditioning in Acute Ischaemic Stroke (TRICS): Protocol of multicentre, parallel group, randomised, preclinical trial in female and male rat and mouse from the Italian Stroke Organization (ISO) Basic Science network

INTRODUCTION: Multicentre preclinical randomised controlled trials (pRCT) are emerging as a necessary step to confirm efficacy and improve translation into the clinic. The aim of this project is to perform two multicentre pRCTs (one in rats and one in mice) to investigate the efficacy of remote ischaemic conditioning (RIC) in an experimental model of severe ischaemic stroke. METHODS AND ANALYSIS: Seven research laboratories within the Italian Stroke Organization (ISO) Basic Science network will participate in the study. Transient endovascular occlusion of the proximal right middle cerebral artery will be performed in two species (rats and mice) and in both sexes. Animals will be randomised to receive RIC by transient surgical occlusion of the right femoral artery, or sham surgery, after reperfusion. Blinded outcome assessment will be performed for dichotomised functional neuroscore (primary endpoint) and infarct volume (secondary endpoint) at 48 hours. A sample size of 80 animals per species will yield 82% power to detect a significant difference of 30% in the primary outcome in both pRCTs. Analyses will be performed in a blind status and according to an intention-to-treat paradigm. The results of this study will provide robust, translationally oriented, high-quality evidence on the efficacy of RIC in multiple species of rodents with large ischaemic stroke. ETHICS AND DISSEMINATION: This is approved by the Animal Welfare Regulatory Body of the University of Milano Bicocca, under project license from the Italian Ministry of Health. Trial results will be subject to publication according to the definition of the outcome presented in this protocol. TRIAL REGISTRATION NUMBER: PCTE0000177