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Drug addiction is a chronic brain disease and drugs of abuse cause long lasting neuroadaptations. Addiction is characterized by the loss of control over drug use despite harmful consequences, and high rates of relapse even after long periods of abstinence. Neurotrophic factors (NTFs) are well known for their actions on neuronal survival in the peripheral nervous system. Moreover, NTFs have been shown to be involved in synaptic plasticity in the brain. Brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) are two of the most studied NTFs and both of them have been reported to increase craving when administered into the mesocorticolimbic dopaminergic system after drug self-administration. Here we review recent data on BDNF and GDNF functions in addiction-related behavior and discuss them in relation to previous findings. Finally, we give an insight into how new technologies could aid in further elucidating the role of these factors in drug addiction.

Summary: Retention of critical endoplasmic reticulum (ER) luminal proteins needed to carry out diverse functions (e.g., protein synthesis and folding, lipid metabolism) is mediated through a carboxy-terminal ER retention sequence (ERS) and its interaction with KDEL receptors. Here, we demonstrate that depleting ER calcium causes mass departure of ERS-containing proteins from cells by overwhelming KDEL receptors. In addition, we provide evidence that KDELR2 and KDELR3, but not KDELR1, are unfolded protein response (UPR) genes upregulated as an adaptive response to counteract the loss of ERS-containing proteins, suggesting previously unknown isoform-specific functions of the KDEL receptors. Overall, our findings establish that decreases in ER calcium change the composition of the ER luminal proteome and secretome, which can impact cellular functions and cell viability. The redistribution of the ER proteome from inside the cell to the outside has implications for dissecting the complex relationship of ER homeostasis with diverse disease pathologies. : Trychta et al. identify an exodus of resident proteins from the endoplasmic reticulum (ER) in response to the loss of luminal ER calcium. They show that the cell works to maintain the ER proteome under calcium depletion by upregulating KDEL receptors, which act as unfolded protein response genes. Keywords: endoplasmic reticulum, calcium, KDEL receptor, ER retention sequence, XBP1, UPR, unfolded protein response, MANF

Glial cell line-derived neurotrophic factor (GDNF) is one of the most studied neurotrophic factors. GDNF has two splice isoforms, full-length pre-α-pro-GDNF (α-GDNF) and pre-β-pro-GDNF (β-GDNF), which has a 26 amino acid deletion in the pro-region. Thus far, studies have focused solely on the α-GDNF isoform, and nothing is known about the in vivo effects of the shorter β-GDNF variant. Here we compare for the first time the effects of overexpressed α-GDNF and β-GDNF in non-lesioned rat striatum and the partial 6-hydroxydopamine lesion model of Parkinson's disease. GDNF isoforms were overexpressed with their native pre-pro-sequences in the striatum using an adeno-associated virus (AAV) vector, and the effects on motor performance and dopaminergic phenotype of the nigrostriatal pathway were assessed. In the non-lesioned striatum, both isoforms increased the density of dopamine transporter-positive fibers at 3 weeks after viral vector delivery. Although both isoforms increased the activity of the animals in cylinder assay, only α-GDNF enhanced the use of contralateral paw. Four weeks later, the striatal tyrosine hydroxylase (TH)-immunoreactivity was decreased in both α-GDNF and β-GDNF treated animals. In the neuroprotection assay, both GDNF splice isoforms increased the number of TH-immunoreactive cells in the substantia nigra but did not promote behavioral recovery based on amphetamine-induced rotation or cylinder assays. Thus, the shorter GDNF isoform, β-GDNF, and the full-length α-isoform have comparable neuroprotective efficacy on dopamine neurons of the nigrostriatal circuitry.

Mammalian birth is accompanied by a period of obligatory asphyxia, which consists of hypoxia (drop in blood O2 levels) and hypercapnia (elevation of blood CO2 levels). Prolonged, complicated birth can extend the asphyxic period, leading to a pathophysiological situation, and in humans, to the diagnosis of clinical birth asphyxia, the main cause of hypoxic-ischemic encephalopathy (HIE). The neuroendocrine component of birth asphyxia, in particular the increase in circulating levels of arginine vasopressin (AVP), has been extensively studied in humans. Here we show for the first time that normal rat birth is also accompanied by an AVP surge, and that the fetal AVP surge is further enhanced in a model of birth asphyxia, based on exposing 6-day old rat pups to a gas mixture containing 4% O2 and 20% CO2 for 45 min. Instead of AVP, which is highly unstable with a short plasma half-life, we measured the levels of copeptin, the C-terminal part of prepro-AVP that is biochemically much more stable. In our animal model, the bulk of AVP/copeptin release occurred at the beginning of asphyxia (mean 7.8 nM after 15 min of asphyxia), but some release was still ongoing even 90 min after the end of the 45 min experimental asphyxia (mean 1.2 nM). Notably, the highest copeptin levels were measured after hypoxia alone (mean 14.1 nM at 45 min), whereas copeptin levels were low during hypercapnia alone (mean 2.7 nM at 45 min), indicating that the hypoxia component of asphyxia is responsible for the increase in AVP/copeptin release. Alternating the O2 level between 5 and 9% (CO2 at 20%) with 5 min intervals to mimic intermittent asphyxia during prolonged labor resulted in a slower but quantitatively similar rise in copeptin (peak of 8.3 nM at 30 min). Finally, we demonstrate that our rat model satisfies the standard acid-base criteria for birth asphyxia diagnosis, namely a drop in blood pH below 7.0 and the formation of a negative base excess exceeding −11.2 mmol/l. The mechanistic insights from our work validate the use of the present rodent model in preclinical work on birth asphyxia.

The endoplasmic reticulum (ER) is essential to many cellular processes including protein processing, lipid metabolism and calcium storage. The ability to longitudinally monitor ER homeostasis in the same organism would offer insight into progressive molecular and cellular adaptations to physiologic or pathologic states, but has been challenging. We recently described the creation of a Gaussia luciferase (GLuc)-based secreted ER calcium-modulated protein (SERCaMP or GLuc-SERCaMP) to longitudinally monitor ER calcium homeostasis. Here we describe a complementary tool to measure the unfolded protein response (UPR), utilizing a UPRE-driven secreted Nano luciferase (UPRE-secNLuc) to examine the activating transcription factor-6 (ATF6) and inositol-requiring enzyme 1 (IRE1) pathways of the UPR. We observed an upregulation of endogenous ATF6- and XBP1-regulated genes following pharmacologically-induced ER stress that was consistent with responsiveness of the UPRE sensor. Both GLuc and NLuc-based reporters have favorable properties for in vivo studies, however, they are not easily used in combination due to overlapping substrate activities. We describe a method to measure the enzymatic activities of both reporters from a single sample and validated the approach using culture medium and rat blood samples to measure GLuc-SERCaMP and UPRE-secNLuc. Measuring GLuc and NLuc activities from the same sample allows for the robust and quantitative measurement of two cellular events or cell populations from a single biological sample. This study is the first to describe the in vivo measurement of UPRE activation by sampling blood, using an approach that allows concurrent interrogation of two components of ER homeostasis.

Abstract Background Tobacco-free nicotine pouches is a novel category of oral nicotine-delivery products. Among current tobacco users such pouches may serve as a low-risk alternative to cigarettes or conventional, tobacco-based oral products e.g., snus and moist snuff. In the United States (U.S.), the market leading nicotine-pouch brand is ZYN®. However, no data on the chemical characteristics of ZYN have been published. Methods We screened for 43 compounds potentially present in tobacco products in seven oral nicotine-delivery products: ZYN (dry and moist), snus (General®), moist snuff (CRP2.1 and Grizzly Pouches Wintergreen), and two pharmaceutical, nicotine replacement therapy products (NRTs, Nicorette® lozenge and Nicotinell® gum). Thirty-six of the tested compounds are classified as harmful and potentially harmful constituents (HPHCs) by the Center for Tobacco Products at the U.S. Food and Drug Administration (FDA-CTP). Five additional compounds were included to cover the GOTHIATEK® product standard for Swedish snus and the last two compounds were chosen to include the four primary tobacco specific nitrosamines (TSNAs). Results The tested products contained nicotine at varying levels. The two ZYN products contained no nitrosamines or polycyclic aromatic hydrocarbons (PAHs) but low levels of ammonia, chromium, formaldehyde, and nickel. In the NRT products we quantified low levels of acetaldehyde, ammonia, cadmium, chromium, lead, nickel, uranium-235, and uranium-238. The largest number (27) and generally the highest levels of HPHCs were quantified in the moist snuff products. For example, they contained six out of seven tested PAHs, and seven out of ten nitrosamines (including NNN and NNK). A total of 19 compounds, none of which were PAHs, were quantified at low levels in the snus product. NNN and NNK levels were five to 12-fold lower in snus compared to the moist snuff products. Conclusions No nitrosamines or PAHs were quantified in the ZYN and NRT products. Overall, the number of quantified HPHCs were similar between ZYN and NRT products and found at low levels.

Abstract Background Newly graduated doctors find their first months of practice challenging and overwhelming. As the newly graduated doctors need help to survive this period, collaborators such as peers, senior doctors, registered nurses and other junior doctors are crucial. However, little is known about what characterise these collaborations, and how much is at stake when newly graduated doctors are striving to establish and maintain them. This study aims to describe and explore the collaborations in depth from the newly graduated doctors’ point of view. Methods We conducted 135 h of participant observations among newly graduated doctors (n = 11), where the doctors were observed throughout their working hours at various times of the day and the week. Furthermore, six semi-structured interviews (four group interviews and two individual) were carried out. The data was analysed thematically. Results Newly graduated doctors consulted different collaborators (peers, senior doctors, registered nurses, and other junior doctors) dependent on the challenge at hand, and they used different strategies to get help and secure good relationships with their collaborators: 1) displaying competence; 2) appearing humble; and 3) playing the game. Their use of different strategies shows how they are committed to engage in these collaborations, and how much is at stake. Conclusions Newly graduated doctors rely on building relationships with different collaborators in order to survive their first months of practice. We argue that the collaboration with peer NGDs and registered nurses has not received the attention it deserves when working with the transition from medical school. We highlight how it is important to focus on these and other collaborators and discuss different work-agendas, mutual expectations, and interdependence. This could be addressed in the introduction period and be one way to ensure a better learning environment and a respectful interprofessional culture.

Abstract Background Despite increased focus on improving the transition from being a medical student to working as a junior doctor, many newly graduated doctors (NGD) report the process of fitting the white coat as stressful, and burnout levels indicate that they might face bigger challenges than they can handle. During this period, the NGDs are in a process of learning how to be doctors, and this takes place in an organisation where the workflow and different priorities set the scene. However, little is known about how the hospital organisation influences this process. Thus, we aimed to explore how the NGDs experience their first months of work in order to understand 1) which struggles they are facing, and 2) which contextual factors within the hospital organisation that might be essential in this transition. Methods An ethnographic study was conducted at a university hospital in Denmark including 135 h of participant observations of the NGDs (n = 11). Six semi-structured interviews (four group interviews and two individual interviews) were conducted (n = 21). The analysis was divided into two steps: Firstly, we carried out a “close-to-data” analysis with focus on the struggles faced by the NGDs. Secondly, we reviewed the struggles by using the theoretical lens of Cultural Historical Activity Theory (CHAT) to help us explore, which contextual factors within the hospital organisation that seem to have an impact on the NGDs’ experiences. Results The NGDs’ struggles fall into four themes: Responsibility, local knowhow, time management and collaborators. By using the CHAT lens, we were able to identify significant contextual factors, including a physically remote placement, a missing overlap between new and experienced NGDs, a time limited introduction period, and the affiliation to several departments. These struggles and factors were highly intertwined and influenced by one another. Conclusion Contextual factors within the hospital organisation may aggravate the struggles experienced by the NGDs, and this study points to possible elements that could be addressed to make the transition less challenging and overwhelming.

Learning and assessment are increasingly mediated by digital technologies. Thus, learners’ experiences with these digital technologies are growing in importance, as they might affect learning and assessment. The present paper explores the impact of user experience on digital concept mapping. It builds on user experience theory to explain variance in the intention to use digital concept mapping tools and in concept map-based assessment scores. Furthermore, it identifies fulfillment of psychological needs as an important driver of positive experiences. In a field study in three schools and a university (N = 71), we tested two concept mapping prototypes on computers and tablets. We found that user experience is a significant factor explaining variance in intention to use. User experience also explained variance in three out of four concept mapping scores on tablets, potentially related to the lower pragmatic quality of the tablet prototypes. Fulfillment of psychological needs strongly affected perceptions of different qualities of user experience with digital concept mapping. These results indicate that user experience needs to be considered in digital concept mapping to provide a positive and successful environment for learning and assessment. Finally, we discuss implications for designers of digital learning and assessment tools.

The link between stratification and educational inequality in empirical research is well documented. Some countries – particularly those that do not follow the model of comprehensive schools – discuss the possibility of increasing permeability between school tracks to reduce inequalities. This paper focuses on the occurrence of permeability in the stratified school system of Luxembourg and examines what this permeability entails for certain risk groups, specifically students from lower social background, male students and migrants. Educational pathways were classified (cluster analysis) on the basis of an administrative panel data set (n=5301); mechanisms behind educational decisions were analysed as a second step by estimating logistic regressions (Boudon, 1974). The findings show that reorientations in Luxembourg are often determined by the students’ social group, and that permeability – as blurred educational boundaries – mainly reproduces disparities in track placement.