Long-term treadmill exercise upregulated hippocampal learning-related genes without improving cognitive behaviour in socially isolated rats

Background: Some environment enrichments such as exercise has been reported to improve the diminished cognitive functions and related gene expression. Therefore, we aimed to investigate the effects of prolonged treadmill exercise on long-term learning and hippocampal gene expression, which involves learning and plasticity. Materials and methods: Male Wistar rats (n = 32) randomly assigned into four groups: control (C), social isolation (SI), exercised (E), social isolation + exercise (SE) during postnatal days (PNDs) 21–34. Social isolation protocol was applied during 14 days by placing the rat alone in a cage. Rats were exercised daily, 5 days per week, for overall 4 weeks. Finally, learning performance was evaluated by the novel object recognition test. At the end of learning test, the rats were decapitated to isolate hippocampus tissues for learning related gene expression such as N-methyl-d-aspartate receptor (NMDAR) subunit genes (Grin1, Grin2a, Grin2b) and cyclin dependent kinase 5 (Cdk5), Cdk5 regulatory subunit p35 (Cdk5r), activity-regulated, cytoskeletal-associated protein (Arc), the immediate early gene (c-Fos, a marker of neuronal activation), doublecortin (DCX), achaetescute homolog 1 (ASCL1), brain-derived neurotrophic factor (BDNF) by real-time polymerase chain reaction (RT-PCR). Results: Grin1, NMDAR subunit gene expression was increased significantly in E group compared to other groups. Grin2b, NMDAR subunit gene expression was increased in E group compared to the SI group. Cdk5 level increased in E group compared to the SE group. The ASCL1 gene expression increased in E group compare to the SE group. The DCX gene expression increasing in C group compared to SI and SE groups. Conclusions: Taken together these findings may point out that long-term social isolation down-regulated learning-related genes. However, treadmill exercise together with social isolation did not restore this down-regulation although treadmill exercise increased learning-related genes without improving cognitive behaviour

How scientists and physicians use Twitter during a medical congress

OBJECTIVES: During medical congresses Twitter allows discussions to disseminate beyond the congress hall and reach a wider audience. Insights into the dynamics of social media interactions during congresses, dissemination of scientific information and the determinants of a successful tweet may allow us to better understand social media's role in science communication. METHODS: We retrospectively extracted social media data during the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) 2017 and 2018 using NodeXL. We compared social media activity during these two congresses. Subsequently, we conducted in-depth analyses to identify the components of a successful tweet and multivariable analysis to assess independent factors associated with retweet activity. RESULTS: In 2018, approximately 13,000 delegates attended ECCMID, but only 591 Twitter accounts actively tweeted about the congress. Although fewer tweets were posted in 2018 compared to 2017 (4,213 vs 4,657, respectively), ECCMID2018 generated a 63% increase in the total number of retweets (p <0.001). According to multivariable logistic regression analysis, using multimedia, URL or hashtags and mentioning other Twitter account(s) were independently associated with retweet success. Mentioning of other users and use of multimedia were the only consistent predictors of retweets irrespective of the number of followers. CONCLUSIONS: A substantial increase in retweet activity and a modest increase in the number of influential Twitter accounts were observed between two successive congresses. Dissemination of scientific messages is more successful when connected accounts are actively involved in social media activity, and social media posts constitute the right combination of components.PostprintPeer reviewe

Joubert syndrome Arl13b functions at ciliary membranes and stabilizes protein transport in Caenorhabditis elegans

The small ciliary G protein Arl13b is required for cilium biogenesis and sonic hedgehog signaling and is mutated in patients with Joubert syndrome (JS). In this study, using Caenorhabditis elegans and mammalian cell culture systems, we investigated the poorly understood ciliary and molecular basis of Arl13b function. First, we show that Arl13b/ARL-13 localization is frequently restricted to a proximal ciliary compartment, where it associates with ciliary membranes via palmitoylation modification motifs. Next, we find that loss-of-function C. elegans arl-13 mutants possess defects in cilium morphology and ultrastructure, as well as defects in ciliary protein localization and transport; ciliary transmembrane proteins abnormally accumulate, PKD-2 ciliary abundance is elevated, and anterograde intraflagellar transport (IFT) is destabilized. Finally, we show that arl-13 interacts genetically with other ciliogenic and ciliary transport-associated genes in maintaining cilium structure/morphology and anterograde IFT stability. Together, these data implicate a role for JS-associated Arl13b at ciliary membranes, where it regulates ciliary transmembrane protein localizations and anterograde IFT assembly stability

Islamic Monetary Economics: Insights from the Literature

This chapter reviews critical early literature of Islamic monetary economics. The prohibition of Riba has imposed challenges on Islamic economists to come up with the viable alternatives to achieve Islamic monetary policy goals. Our extensive review of theoretical and empirical literature indicates that equity based profit- and loss-sharing instruments have been proposed for conducting open market operations in an interest-free economy. Theoretically, the central bank can achieve desired goals by controlling money supply and profit-sharing ratios. The findings from empirical literature suggest that money demand tend to be more stable in an interest-free economy. Whether monetary transmission works through Islamic banking channel is controversial, but the literature is growing. These findings are not surprising as majority Muslim countries lack sustainable and equitable economic growth. Moreover, these countries suffer from higher inflation and unemployment with little or no monetary freedom due to fixed exchange rate regime, shallow financial markets and strict capital control

Outcomes of COVID-19 related hospitalization among people with HIV in the ISARIC WHO Clinical Characterization Protocol (UK): a prospective observational study

BACKGROUND: Evidence is conflicting about how HIV modulates COVID-19. We compared the presentation characteristics and outcomes of adults with and without HIV who were hospitalized with COVID-19 at 207 centers across the United Kingdom and whose data were prospectively captured by the ISARIC WHO CCP study. METHODS: We used Kaplan-Meier methods and Cox regression to describe the association between HIV status and day-28 mortality, after separate adjustment for sex, ethnicity, age, hospital acquisition of COVID-19 (definite hospital acquisition excluded), presentation date, ten individual comorbidities, and disease severity at presentation (as defined by hypoxia or oxygen therapy). RESULTS: Among 47,592 patients, 122 (0.26%) had confirmed HIV infection and 112/122 (91.8%) had a record of antiretroviral therapy. At presentation, HIV-positive people were younger (median 56 versus 74 years; p<0.001) and had fewer comorbidities, more systemic symptoms and higher lymphocyte counts and C-reactive protein levels. The cumulative day-28 mortality was similar in the HIV-positive vs. HIV-negative groups (26.7% vs. 32.1%; p=0.16), but in those under 60 years of age HIV-positive status was associated with increased mortality (21.3% vs. 9.6%; p<0.001 [log-rank test]). Mortality was higher among people with HIV after adjusting for age (adjusted hazard ratio [aHR] 1.47, 95% confidence interval [CI] 1.01-2.14; p=0.05), and the association persisted after adjusting for the other variables (aHR 1.69; 95% CI 1.15-2.48; p=0.008) and when restricting the analysis to people aged <60 years (aHR 2.87; 95% CI 1.70-4.84; p<0.001). CONCLUSIONS: HIV-positive status was associated with an increased risk of day-28 mortality among patients hospitalized for COVID-19

Cd81 Interacts with the T Cell Receptor to Suppress Signaling

CD81 (TAPA-1) is a ubiquitously expressed tetraspanin protein identified as a component of the B lymphocyte receptor (BCR) and as a receptor for the Hepatitis C Virus. In an effort to identify trans-membrane proteins that interact with the T-cell antigen receptor (TCR), we performed a membrane yeast two hybrid screen and identified CD81 as an interactor of the CD3delta subunit of the TCR. We found that in the absence of CD81, in thymocytes from knockout mice, TCR engagement resulted in stronger signals. These results were recapitulated in T cell lines that express low levels of CD81 through shRNA mediated silencing. Increased signaling did not result from alterations in the levels of TCR on the surface of T lymphocytes. Although CD81 is not essential for normal T lymphocyte development, it plays an important role in regulating TCR and possibly pre-TCR signal transduction by controlling the strength of signaling. CD81 dependent alterations in thymocyte signaling are evident in increased CD5 expression on CD81 deficient double positive (DP) thymocytes. We conclude that CD81 interacts with the T cell receptor to suppress signaling. © 2012 Cevik et al