Evaluation of a risk assessment system for heritage railway earthworks

There are currently over 100 heritage railways in the UK carrying 6.8 million passengers on 15 million passenger journeys and contributing an estimated £579 million to the UK economy. Many of these lines include significant earthworks, which present a considerable risk to their safe operation. In the last decade there have been major slips at several heritage railways causing major disruption to operations and a serious threat to business continuity. This research describes the application of a risk assessment system based on that used by Network Rail but specifically adapted for heritage railway conditions. Adaptations include significant alterations to the consequence categories used in prioritization of earthwork issues and a simple low-cost method of implementation based on paper forms and Excel spreadsheets. Use of the system on two heritage railways, the Bo’ness and Kinneil Railway and the Strathspey Railway is evaluated by means of discussion with railway engineering staff and civil engineering volunteers. It is concluded that whilst the system represents a realistic and useful approach to management of earthwork assets, the system could not be used by heritage railway volunteer staff without targeted training. Such training, however, would be straightforward to provide, perhaps under the auspices of the Heritage Railway Association

Role of Acetaldehyde in Ethanol Reversal of Tolerance to Morphine-Induced Respiratory Depression in Mice

BACKGROUND: Opioid users regularly consume other drugs such as alcohol (ethanol). Acute administration of ethanol rapidly reverses tolerance to morphine-induced respiratory depression. However, recent research has suggested that the primary metabolite of ethanol, acetaldehyde, may play a key role in mediating the CNS effects seen after ethanol consumption. This research investigated the role of acetaldehyde in ethanol reversal of tolerance to morphine-induced respiratory depression. METHODS: Tolerance was induced in mice by 6-days implantation of a 75 mg morphine pellet with control mice implanted with a placebo pellet. Tolerance was assessed by acute morphine administration on day 6 and respiration measured by plethysmography. Levels of acetaldehyde were inhibited or enhanced by pre-treatments with the acetaldehyde chelator D-penicillamine and the inhibitor of acetaldehyde dehydrogenase disulfiram respectively. RESULTS: Morphine pellet implanted mice displayed tolerance to an acute dose of morphine compared to placebo pellet implanted controls. Acute acetaldehyde administration dose-dependently reversed tolerance to morphine respiratory depression. As previously demonstrated, ethanol reversed morphine tolerance, and this was inhibited by D-penicillamine pre-treatment. An acute, low dose of ethanol that did not significantly reverse morphine tolerance was able to do so following disulfiram pre-treatment. CONCLUSION: These data suggest that acetaldehyde, the primary metabolite of ethanol, is responsible for the reversal of morphine tolerance observed following ethanol administration

ARF6 Activated by the LHCG Receptor through the Cytohesin Family of Guanine Nucleotide Exchange Factors Mediates the Receptor Internalization and Signaling

The luteinizing hormone chorionic gonadotropin receptor (LHCGR) is a G(s)-coupled GPCR that is essential for the maturation and function of the ovary and testis. LHCGR is internalized following its activation, which regulates the biological responsiveness of the receptor. Previous studies indicated that ADP-ribosylation factor (ARF)6 and its GTP-exchange factor (GEF) cytohesin 2 regulate LHCGR internalization in follicular membranes. However, the mechanisms by which ARF6 and cytohesin 2 regulate LHCGR internalization remain incompletely understood. Here we investigated the role of the ARF6 signaling pathway in the internalization of heterologously expressed human LHCGR (HLHCGR) in intact cells using a combination of pharmacological inhibitors, siRNA and the expression of mutant proteins. We found that human CG (HCG)-induced HLHCGR internalization, cAMP accumulation and ARF6 activation were inhibited by Gallein (βγ inhibitor), Wortmannin (PI 3-kinase inhibitor), SecinH3 (cytohesin ARF GEF inhibitor), QS11 (an ARF GAP inhibitor), an ARF6 inhibitory peptide and ARF6 siRNA. However, Dynasore (dynamin inhibitor), the dominant negative mutants of NM23-H1 (dynamin activator) and clathrin, and PBP10 (PtdIns 4,5-P2-binding peptide) inhibited agonist-induced HLHCGR and cAMP accumulation but not ARF6 activation. These results indicate that heterotrimeric G-protein, phosphatidylinositol (PI) 3-kinase (PI3K), cytohesin ARF GEF and ARF GAP function upstream of ARF6 whereas dynamin and clathrin act downstream of ARF6 in the regulation of HCG-induced HLHCGR internalization and signaling. In conclusion, we have identified the components and molecular details of the ARF6 signaling pathway required for agonist-induced HLHCGR internalization