The 5' → 3' exoribonuclease XRN1/Pacman and its functions in cellular processes and development

XRN1 is a 5' → 3' processive exoribonuclease that degrades mRNAs after they have been decapped. It is highly conserved in all eukaryotes, including homologs in Drosophila melanogaster (Pacman), Caenorhabditis elegans (XRN1), and Saccharomyces cerevisiae (Xrn1p). As well as being a key enzyme in RNA turnover, XRN1 is involved in nonsense-mediated mRNA decay and degradation of mRNAs after they have been targeted by small interfering RNAs or microRNAs. The crystal structure of XRN1 can explain its processivity and also the selectivity of the enzyme for 5' monophosphorylated RNA. In eukaryotic cells, XRN1 is often found in particles known as processing bodies (P bodies) together with other proteins involved in the 5' → 3' degradation pathway, such as DCP2 and the helicase DHH1 (Me31B). Although XRN1 shows little specificity to particular 5' monophosphorylated RNAs in vitro, mutations in XRN1 in vivo have specific phenotypes suggesting that it specifically degrades a subset of RNAs. In Drosophila, mutations in the gene encoding the XRN1 homolog pacman result in defects in wound healing, epithelial closure and stem cell renewal in testes. We propose a model where specific mRNAs are targeted to XRN1 via specific binding of miRNAs and/or RNA-binding proteins to instability elements within the RNA. These guide the RNA to the 5' core degradation apparatus for controlled degradation

Post‐transcriptional gene regulation by the exoribonuclease Pacman

The gene pacman (pcm) in Drosophila melanogaster encodes the exoribonuclease XRN1, which is highly conserved across eukaryotes and is the only known cytoplasmic exoribonuclease that degrades RNA in the 5’ – 3’ direction. Hypomorphic mutations to pacman have previously been shown cause developmental phenotypes, particularly during wing and thorax development. The focus of this thesis was twofold. Firstly, to create a null pacman allele and associated control lines to further characterise the phenotypes of pcm. Two new alleles were created, one of which was amorphic (pcm14). pcm14 is 100% lethal, and flies die during pupation. The wing imaginal discs of pcm14 larvae are less than half the size of those in wild‐type larvae at the same stage (3rd instar). It was also found that wing imaginal discs in the hypomorphic mutant pcm5 are significantly smaller than wild‐type, by almost 20%. Therefore, pcm appears to play a role in cell proliferation or apoptosis during the growth of wing imaginal discs. Along with pcm14, a new deficiency that includes pcm was created using a DrosDel Rearrangement Screen. The 17,963bp Df(1)ED7452 deficiency is >13 times smaller than the two other publically available deficiencies that include pcm

A randomised controlled trial of a telephone administered brief HIV risk reduction intervention amongst men who have sex with men prescribed post-exposure prophylaxis for HIV after sexual exposure in the UK: Project PEPSE

Background In western countries, men who have sex with men (MSM) are most affected by HIV and increasingly likely to engage in risky sexual behaviour. MSM who experience a potential sexual exposure to HIV (PEPSE) and receive a preventative regimen of anti-HIV treatment are at particularly high risk of acquiring HIV and could potentially benefit from targeted risk reduction behavioural interventions such as motivational interviewing (MI). Purpose The aim of this trial was to examine the impact of augmented MI (MI plus information provision and behavioural skills building), over and above routine care, on reducing risky sexual behaviour in MSM prescribed PEPSE. Secondary aims of the research were to examine whether the intervention reduced sexually transmitted infections (STI) and further requests for PEP. Methods A parallel-group pragmatic randomised controlled trial was conducted with 175 MSM recruited from five sexual health (SH) clinics in the south east of England. The intervention was two fixed-duration sessions of telephone administered augmented MI. A manual guided the selection of individualised persuasive communication strategies based on underlying change mechanisms specified by the Information, Motivation and Behavioural Skills (IMB) model. Primary outcomes were the number of receptive and active anal intercourse (AI) partners, the use of condoms every time during receptive and active AI and the use of condoms sometimes during receptive and active AI. Results There were no significant impacts on sexual risk behaviour or any of the psychological measures, and no discernible reduction in requests for repeat PEP or rates of STIs within a year. Conclusion Our behavioural intervention of augmented MI did not affect risky sexual behaviour, rates of further PEP and STIs, and psychological factors, in MSM prescribed PEPSE. Trial registration numbers: UKCRN ID:11436; ISRCTN00746242

Radiation capture and conversion efficiencies of Miscanthus sacchariflorus, M. sinensis and their naturally occurring hybrid M. × giganteus

Miscanthus is a rhizomatous C4 grass of great interest as a biofuel crop because it has the potential to produce high yields over a wide geographical area with low agricultural inputs on marginal land less suitable for food production. At the moment, a clonal interspecific hybrid Miscanthusxgiganteus is the most widely cultivated and studied in Europe and the United States, but breeding programmes are developing newer more productive varieties. Here, we quantified the physiological processes relating to whole season yield in a replicated plot trial in Wales, UK. Light capture and conversion efficiency were parameterized for four carefully selected genotypes (M.sinensis, M.sacchariflorus and Miscanthusxgiganteus). Differences in the canopy architecture in mature stands as measured by the extinction coefficient (k) were small (0.55-0.65). Sensitivity analysis on a mathematical model of Miscanthus was performed to quantify the accumulative intercepted photosynthetically active radiation (iPAR) in the growing season using (i) k, (ii) variation in the thermal responses of leaf expansion rate, (iii) base temperature for degree days and (iv) date start of canopy expansion. A 10% increase in k or leaf area per degree day both had a minimal effect on iPAR (3%). Decreasing base temperature from 10 to 9 degrees C gave an 8% increase in iPAR. If the starting date for canopy expansion was the same as shoot emergence date, then the iPAR increases by 12.5%. In M.xgiganteus, the whole season above ground and total (including below ground) radiation-use efficiency (RUE) ranged from 45% to 37% higher than the noninterspecific hybrid genotypes. The greater yields in the interspecific hybrid M.xgiganteus are explained by the higher RUE and not by differences in iPAR or partitioning effects. Studying the mechanisms underlying this complex trait could have wide benefits for both fuel and food production

Statistical analysis plan for the Early Youth Engagement in first episode psychosis (EYE-2) study: a pragmatic cluster randomised controlled trial of implementation, effectiveness and cost-effectiveness of a team-based motivational engagement intervention to improve engagement

Background Early Intervention in Psychosis (EIP) services improve health outcomes for young people with psychosis in the medium-long term, but 25% of young people disengage in the first 12 months with costs to their mental health, families, society and health services. This study will evaluate the effectiveness of a team-based motivational engagement intervention, the Early Youth Engagement (EYE-2) intervention. Methods and design The EYE-2 trial is a cluster randomised controlled trial comparing the EYE-2 intervention plus standardised EIP service to standardised EIP service alone, with randomisation at the clinical team (cluster) level. The study aimed to enrol 950 young people (aged 14–35 years) with first episode psychosis in 10 teams per arm. Results The primary outcome is time to disengagement: days from the date of allocation to care coordinator to date of the last contact following either refusal to engage with an EIP team or lack of response to EIP contact for 3 consecutive months which will be analysed using a shared frailty model. Secondary outcomes are Health of the Nation Outcome Scale (HoNOS), Process of Recovery Questionnaire (QPR), DIALOG (a service user-reported measure of quality of life and treatment satisfaction) and service use outcomes which will be analysed using mixed effects regression models. Discussion This paper is the detailed statistical analysis plan for the EYE-2 trial. Any changes to, or deviations from, this plan will be described and justified in the final trial report. Trial registration ISRCTN 51629746. Prospectively registered on 7 May 2019. Date assigned 10 May 2019

Scabies outbreaks in ten care homes for elderly people: a prospective study of clinical features, epidemiology, and treatment outcomes

Background Scabies outbreaks in residential and nursing care homes for elderly people are common, subject to diagnostic delay, and hard to control. We studied clinical features, epidemiology, and outcomes of outbreaks in the UK between 2014 and 2015. Methods We did a prospective observational study in residential care homes for elderly people in southeast England that reported scabies outbreaks to Public Health England health protection teams. An outbreak was defined as two or more cases of scabies (in either residents or staff) at a single care home. All patients who provided informed consent were included; patients with dementia were included if a personal or nominated consultee (ie, a family member or nominated staff member) endorsed participation. Dermatology-trained physicians examined residents at initial clinical visits, which were followed by two mass treatments with topical scabicide as per local health protection team guidance. Follow-up clinical visits were held 6 weeks after initial visits. Scabies was diagnosed through pre-defined case definitions as definite, probable, or possible with dermatoscopy and microscopy as appropriate. Findings 230 residents were examined in ten outbreaks between Jan 23, 2014, and April 13, 2015. Median age was 86·9 years (IQR 81·5–92·3), 174 (76%) were female, and 157 (68%) had dementia. 61 (27%) residents were diagnosed with definite, probable, or possible scabies, of whom three had crusted scabies. Physical signs differed substantially from classic presentations. 31 (51%) of the 61 people diagnosed with scabies were asymptomatic, and only 25 (41%) had burrows. Mites were visualised with dermatoscopy in seven (11%) patients, and further confirmed by microscopy in three (5%). 35 (57%) cases had signs of scabies only on areas of the body that would normally be covered. Dementia was the only risk factor for a scabies diagnosis that we identified (odds ratio 2·37 [95% CI 1·38–4·07]). At clinical follow-up, 50 people who were initially diagnosed with scabies were examined. No new cases of scabies were detected, but infestation persisted in ten people. Interpretation Clinical presentation of scabies in elderly residents of care homes differs from classic descriptions familiar to clinicians. This difference probably contributes to delayed recognition and suboptimal management in this vulnerable group. Dermatoscopy and microscopy were of little value. Health-care workers should be aware of the different presentation of scabies in elderly people, and should do thorough examinations, particularly in people with dementia. Funding Public Health England and British Skin Foundation

Novel biomarkers in plasma cell disorders

The invention relates to novel biomarkers for plasma cell disorders, such as multiple myeloma,and in particular the use of microRNAs as diagnostic and prognostic markers in assyas for detecting such disorders. The invention also relates to methods of determining the efficacy of treating such a plasma cell disorder with a therapeutic agent and kits for carrying out the assays and methods. The assays are qualitative and/or quantitative and are adaptable to large-scale screening and clinical trials

Phase I study of TP300 in patients with advanced solid tumors with pharmacokinetic, pharmacogenetic and pharmacodynamic analyses

Background: A Phase I dose escalation first in man study assessed maximum tolerated dose (MTD), dose-limiting toxicity (DLT) and recommended Phase II dose of TP300, a water soluble prodrug of the Topo-1 inhibitor TP3076, and active metabolite, TP3011. <p/>Methods: Eligible patients with refractory advanced solid tumors, adequate performance status, haematologic, renal, and hepatic function. TP300 was given as a 1-hour i.v. infusion 3-weekly and pharmacokinetic (PK) profiles of TP300, TP3076 and TP3011 were analysed. Polymorphisms in CYP2D6, AOX1 and UGT1A1 were studied and DNA strand-breaks measured in peripheral blood mononuclear cells (PBMCs). <p/>Results: 32 patients received TP300 at 1, 2, 4, 6, 8, 10, 12 mg/m2. MTD was 10 mg/m2; DLTs at 12 (2/4 patients) and 10 mg/m2 (3/12) included thrombocytopenia and febrile neutropenia; diarrhea was uncommon. Six patients (five had received irinotecan), had stable disease for 1.5-5 months. TP3076 showed dose proportionality in AUC and Cmax from 1--10 mg/m2. Genetic polymorphisms had no apparent influence on exposure. DNA strand-breaks were detected after TP300 infusion. <p/>Conclusions: TP300 had predictable hematologic toxicity, and diarrhea was uncommon. AUC at MTD is substantially greater than for SN38. TP3076 and TP3011 are equi-potent with SN38, suggesting a PK advantage

A novel mechanism for the anti-cancer activity of aspirin and salicylates

© 2016 The Authors. Published by Spandidos Publications. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3892/ijo.2019.4701Epidemiological studies indicate that long-term aspirin usage reduces the incidence of colorectal cancer (CRC) and may protect against other non-CRC associated adenocarcinomas, including oesophageal cancer. A number of hypotheses have been proposed with respect to the molecular action of aspirin and other non‑steroidal anti‑inflammatory drugs in cancer development. The mechanism by which aspirin exhibits toxicity to CRC has been previously investigated by synthesising novel analogues and derivatives of aspirin in an effort to identify functionally significant moieties. Herein, an early effect of aspirin and aspirin-like analogues against the SW480 CRC cell line was investigated, with a particular focus on critical molecules in the epidermal growth factor (EGF) pathway. The present authors proposed that aspirin, diaspirin and analogues, and diflunisal (a salicylic acid derivative) may rapidly perturb EGF and EGF receptor (EGFR) internalisation. Upon longer incubations, the diaspirins and thioaspirins may inhibit EGFR phosphorylation at Tyr1045 and Tyr1173. It was additionally demonstrated, using a qualitative approach, that EGF internalisation in the SW480 cell line may be directed to endosomes by fumaryldiaspirin using early endosome antigen 1 as an early endosomal marker and that EGF internalisation may also be perturbed in oesophageal cell lines, suggestive of an effect not only restricted to CRC cells. Taken together and in light of our previous findings that the aspirin-like analogues can affect cyclin D1 expression and nuclear factor-κB localisation, it was hypothesized that aspirin and aspirin analogues significantly and swiftly perturb the EGFR axis and that the protective activity of aspirin may in part be explained by perturbed EGFR internalisation and activation. These findings may also have implications in understanding the inhibitory effect of aspirin and salicylates on wound healing, given the critical role of EGF in the response to tissue trauma