463 research outputs found

    Chemokines in the corpus luteum: Implications of leukocyte chemotaxis

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    Chemokines are small molecular weight peptides responsible for adhesion, activation, and recruitment of leukocytes into tissues. Leukocytes are thought to influence follicular atresia, ovulation, and luteal function. Many studies in recent years have focused attention on the characterization of leukocyte populations within the ovary, the importance of leukocyte-ovarian cell interactions, and more recently, the mechanisms of ovarian leukocyte recruitment. Information about the role of chemokines and leukocyte trafficking (chemotaxis) during ovarian function is important to understanding paracrine-autocrine relationships shared between reproductive and immune systems. Recent advances regarding chemokine expression and leukocyte accumulation within the ovulatory follicle and the corpus luteum are the subject of this mini-review

    An investigation of the CPB cysteine proteinases of Leishmania mexicana and their role in intracellular survival

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    The cysteine proteinases of Leishmania mexicana have long been suspected of being important in the virulence of the parasite. This was recently confirmed using analysis of the in vitro and in vivo infectivity of mutant lines lacking in different cysteine proteinase genes (Mottram et al., 1996; Alexander et al., 1998). One component of my study was an investigation of the effect of peptidyl cysteine proteinase inhibitors on L. mexicana. None of the inhibitors tested had any effect on the growth of promastigotes in vitro. However, analysis of the effects on axenic amastigotes demonstrated that cysteine proteinase inhibition reduced growth. The inhibitors were also effective at reducing the cysteine proteinase activity and prevented the complete processing of the pro-enzymes of the cysteine proteinases encoded by CPA and different genes within the CPB array. These effects were consistent with the autocatalytic nature of the processing, although the results also suggested a partial role for CPA in CPB maturation. The loss of mature enzyme and the resultant increase in the number and abundance of precursor enzyme forms manifested itself as the appearance of large matrix-filled vacuoles, indicating a perturbation of intracellular protein trafficking. Analysis of the effect of cysteine proteinase inhibition upon intracellular infection demonstrated that it was possible to reduce the survival of the amastigotes. Interestingly, removal of the CPB array did not reduce the parasite's susceptibility, indicating that other cysteine proteinases are important targets of these inhibitors. My findings, in conjunction with the work of others, confirm the potential of cysteine proteinases as targets for the design of chemotherapeutic agents. An understanding of the mechanisms by which cysteine proteinases are important for the intracellular survival of L. mexicana is essential if these enzymes are to be effectively exploited through chemotherapy. Other components of my study addressed this issue; an investigation of the role of the CPB enzymes in parasite virulence being undertaken. This part of my investigation involved an analysis of the effect of loss of the CPB enzymes using a CPB null mutant (DeltaCPB). An analysis of the response of macrophages to infection with wild-type parasites or DeltaCPB indicated that comparable levels of reactive nitrogen and oxygen intermediates were produced. This suggested that other factors within the host cell were responsible for the reduced virulence of DeltaCPB. The CPB enzymes were shown to have a role in the turn-over of cellular proteins; loss of these enzymes was demonstrated to cause a reduction in the rate of protein turn-over from the cell surface. Furthermore, analysis of the kinetics of attachment and internalisation of wild-type and DeltaCPB promastigotes demonstrated that loss of the CPB array resulted in a prolonged period of interaction of the parasite with the surface of the macrophage. The mechanisms of attachment were investigated and it was demonstrated that promastigotes of both wild-type parasites and DeltaCPB/g2.8 (DeltaCPB re-expressing a single gene copy from the CPB array; this mutant line had been previously demonstrated to have wild-type virulence) rely heavily on attachment to complement receptors, CR3 and CR4, during interaction with the macrophage surface. DeltaCPB, however, was shown to attach via different receptor-ligand interactions. Therefore, loss of the CPB array was shown to alter the surface architecture of promastigotes such that they could no longer enter macrophages via the route utilised by wild-type promastigotes. This alteration in the mechanism of uptake is hypothesised to be important in the poor intracellular survival of the mutants, in that it results in the parasites encountering a different and more hostile intracellular environment

    The University of New Hampshire Engaged Scholars Academy: Instilling in Faculty Principles of Effective Partnership

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    Over the last decade, the University of New Hampshire (UNH) has promoted mutually beneficial partnerships between faculty and community partners vis-à-vis the Engaged Scholars Academy (ESA), a faculty development program aimed at enhancing faculty understanding of the principles of partnership and engaged scholarship. This research seeks to determine whether and how the ESA has impacted faculty-community partnerships around engaged scholarship. Findings suggest that Engaged Scholar Academy participants – as compared to non-participants – have a deeper understanding of the principles of partnership, are more likely to feel their scholarship is enhanced, spend more time with partners, engage their partners throughout the process of inquiry, and focus more on sustaining partnership outcomes

    Optimizing astrophotonic spatial reformatters using simulated on-sky performance

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    One of the most useful techniques in astronomical instrumentation is image slicing. It enables a spectrograph to have a more compact angular slit, whilst retaining throughput and increasing resolving power. Astrophotonic components like the photonic lanterns and photonic reformatters can be used to replace bulk optics used so far. This study investigates the performance of such devices using end-to-end simulations to approximate realistic on-sky conditions. It investigates existing components, tries to optimize their performance and aims to understand better how best to design instruments to maximize their performance. This work complements the recent work in the field and provides an estimation for the performance of the new components.Comment: Conference proceedings in SPIE 2018 Austin Texa

    Daytime site characterisation of La Palma, and its relation to night-time conditions.

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    This paper presents preliminary daytime profiles taken using a Wide-Field Shack-Hartmann Sensor at the Swedish Solar Telescope (SST), La Palma. These are contrasted against Stereo-SCIDAR data from corresponding nights to assess the validity of the assumptions currently used for simulating the performances of possible Multi-Conjugate Adaptive Optics (MCAO) systems for future solar telescopes, especially the assumption that the structure of the high altitude turbulence is mostly similar between the day and the night. We find that for our data both the altitude and the strength of the turbulence differ between the day and the night, although more data is required to draw any conclusions about typical behaviour and conditions

    Characterization of the Ca2+-gated and voltage-dependent k+-channel slo-1 of nematodes and its interaction with emodepside

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    The cyclooctadepsipeptide emodepside and its parent compound PF1022A are broad-spectrum nematicidal drugs which are able to eliminate nematodes resistant to other anthelmintics. The mode of action of cyclooctadepsipeptides is only partially understood, but involves the latrophilin Lat-1 receptor and the voltage- and calcium-activated potassium channel Slo-1. Genetic evidence suggests that emodepside exerts its anthelmintic activity predominantly through Slo-1. Indeed, slo-1 deficient Caenorhabditis elegans strains are completely emodepside resistant. However, direct effects of emodepside on Slo-1 have not been reported and these channels have only been characterized for C. elegans and related Strongylida. Molecular and bioinformatic analyses identified full-length Slo-1 cDNAs of Ascaris suum, Parascaris equorum, Toxocara canis, Dirofilaria immitis, Brugia malayi, Onchocerca gutturosa and Strongyloides ratti. Two paralogs were identified in the trichocephalids Trichuris muris, Trichuris suis and Trichinella spiralis. Several splice variants encoding truncated channels were identified in Trichuris spp. Slo-1 channels of trichocephalids form a monophyletic group, showing that duplication occurred after the divergence of Enoplea and Chromadorea. To explore the function of a representative protein, C. elegans Slo-1a was expressed in Xenopus laevis oocytes and studied in electrophysiological (voltage-clamp) experiments. Incubation of oocytes with 1-10 µM emodepside caused significantly increased currents over a wide range of step potentials in the absence of experimentally increased intracellular Ca2+, suggesting that emodepside directly opens C. elegans Slo-1a. Emodepside wash-out did not reverse the effect and the Slo-1 inhibitor verruculogen was only effective when applied before, but not after, emodepside. The identification of several splice variants and paralogs in some parasitic nematodes suggests that there are substantial differences in channel properties among species. Most importantly, this study showed for the first time that emodepside directly opens a Slo-1 channel, significantly improving the understanding of the mode of action of this drug class

    Onchocerca parasites and Wolbachia endosymbionts: evaluation of a spectrum of antibiotic types for activity against Onchocerca gutturosa in vitro

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    BACKGROUND: The filarial parasites of major importance in humans contain the symbiotic bacterium Wolbachia and recent studies have shown that targeting of these bacteria with antibiotics results in a reduction in worm viability, development, embryogenesis, and survival. Doxycycline has been effective in human trials, but there is a need to develop drugs that can be given for shorter periods and to pregnant women and children. The World Health Organisation-approved assay to screen for anti-filarial activity in vitro uses male Onchocerca gutturosa, with effects being determined by worm motility and viability as measured by reduction of MTT to MTT formazan. Here we have used this system to screen antibiotics for anti-filarial activity. In addition we have determined the contribution of Wolbachia depletion to the MTT reduction assay. METHODS: Adult male O. gutturosa were cultured on a monkey kidney cell (LLCMK 2) feeder layer in 24-well plates with antibiotics and antibiotic combinations (6 to 10 worms per group). The macrofilaricide CGP 6140 (Amocarzine) was used as a positive control. Worm viability was assessed by two methods, (i) motility levels and (ii) MTT/formazan colorimetry. Worm motility was scored on a scale of 0 (immotile) to 10 (maximum) every 5 days up to 40 days. On day 40 worm viability was evaluated by MTT/formazan colorimetry, and results were expressed as a mean percentage reduction compared with untreated control values at day 40. To determine the contribution of Wolbachia to the MTT assay, the MTT formazan formation of an insect cell-line (C6/36) with or without insect Wolbachia infection and treated or untreated with tetracycline was compared. RESULTS: Antibiotics with known anti-Wolbachia activity were efficacious in this system. Rifampicin (5 × 10(-5)M) was the most effective anti-mycobacterial agent; clofazimine (1.25 × 10(-5)M and 3.13 × 10(-6)M) produced a gradual reduction in motility and by 40 days had reduced worm viability. The other anti-mycobacterial drugs tested had limited or no activity. Doxycycline (5 × 10(-5)M) was filaricidal, but minocycline was more effective and at a lower concentration (5 × 10(-5)M and 1.25 × 10(-5)M). Inactive compounds included erythromycin, oxytetracycline, trimethoprim and sulphamethoxazole. The MTT assay on the insect cell-line showed that Wolbachia made a significant contribution to the metabolic activity within the cells, which could be reduced when they were exposed to tetracycline. CONCLUSION: The O. gutturosa adult male screen for anti-filarial drug activity is also valid for the screening of antibiotics for anti-Wolbachia activity. In agreement with previous findings, rifampicin and doxycycline were effective; however, the most active antibiotic was minocycline. Wolbachia contributed to the formation of MTT formazan in the MTT assay of viability and is therefore not exclusively a measure of worm viability and indicates that Wolbachia contributes directly to the metabolic activity of the nematode

    Integrating technology into complex intervention trial processes: a case study

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    This is the final version of the article. Available from BioMed Central via the DOI in this record.Background Trials of complex interventions are associated with high costs and burdens in terms of paperwork, management, data collection, validation, and intervention fidelity assessment occurring across multiple sites. Traditional data collection methods rely on paper-based forms, where processing can be time-consuming and error rates high. Electronic source data collection can potentially address many of these inefficiencies, but has not routinely been used in complex intervention trials. Here we present the use of an on-line system for managing all aspects of data handling and for the monitoring of trial processes in a multicentre trial of a complex intervention. We custom built a web-accessible software application for the delivery of ENGAGE-HD, a multicentre trial of a complex physical therapy intervention. The software incorporated functionality for participant randomisation, data collection and assessment of intervention fidelity. It was accessible to multiple users with differing levels of access depending on required usage or to maintain blinding. Each site was supplied with a 4G-enabled iPad for accessing the system. The impact of this system was quantified through review of data quality and collation of feedback from site coordinators and assessors through structured process interviews. Results The custom-built system was an efficient tool for collecting data and managing trial processes. Although the set-up time required was significant, using the system resulted in an overall data completion rate of 98.5% with a data query rate of 0.1%, the majority of which were resolved in under a week. Feedback from research staff indicated that the system was highly acceptable for use in a research environment. This was a reflection of the portability and accessibility of the system when using the iPad and its usefulness in aiding accurate data collection, intervention fidelity and general administration. Conclusions A combination of commercially available hardware and a bespoke online database designed to support data collection, intervention fidelity and trial progress provides a viable option for streamlining trial processes in a multicentre complex intervention trial. There is scope to further extend the system to cater for larger trials and add further functionality such as automatic reporting facilities and participant management support.The ENGAGE-HD trial was funded by Health and Social Care Wales, United Kingdom. The South East Wales Trials Unit is funded by the Wales Assembly Government through Health and Care Research Wales

    Recruitment and retention of participants from socioeconomically deprived communities : lessons from the Awareness and Beliefs About Cancer (ABACus3) randomised controlled trial

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    Background Recruitment of research participants poses challenges in socioeconomically deprived areas. The Awareness and Beliefs About Cancer (ABACus) phase 3 Randomised Control Trial recruited adult participants from socioeconomically deprived areas using a combined healthcare/community engagement model. We report the strategies used to successfully recruit and retain our trial participant sample. Methods Community and healthcare settings in areas of high socioeconomic deprivation were identified by lay advisors who recruited participants opportunistically or by appointment. Follow-up was done by telephone or post at 2-weeks and 6-months after recruitment, and all participants were offered financial incentives. Qualitative interviews were conducted with lay advisors regarding their experience and reflections. Results The lay advisors identified and contacted 107 potential recruitment venues across South and West Yorkshire and South East Wales of which 41.1% (n = 42) were opened for recruitment. A total of 234 participants were recruited, with 91% (n = 212) retention at 2-weeks and 85% (n = 199) at 6-months. Community settings yielded 75% (n = 176) of participants. Participants had a mean age of 61.3 years and 63.3% (n = 148) were female, with 66% (n = 154) resident in the most deprived geographical areas. Lay advisors described recruitment as intensive, although engaging participants was easier in community settings. Conclusions The ABACus3 trial achieved recruitment and high retention with a population that is often “hard to reach” or entirely missed in health research. Strategies were specifically tailored to engage the venues and adult residents of highly deprived areas. Future studies recruiting adults living in the most deprived areas might benefit from community recruitment and from collaborating with local gatekeepers who are key to engagement. This study adheres to CONSORT guidelines. Trial registration Retrospectively registered with ISRCTN (http://www.isrctn.com/ISRCTN16872545) on 12.01.2018

    Pregnancy and neonatal outcomes of COVID-19: co-reporting of common outcomes from PAN-COVID and AAP SONPM registries

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    OBJECTIVE: Few large cohort studies have reported data on maternal, fetal, perinatal and neonatal outcomes associated with SARS-CoV-2 infection in pregnancy. We report the outcome of infected pregnancies from a collaboration formed early during the pandemic between the investigators of two registries, the UK and global Pregnancy and Neonatal outcomes in COVID-19 (PAN-COVID) study and the US American Academy of Pediatrics Section on Neonatal Perinatal Medicine (AAP SONPM) National Perinatal COVID-19 Registry. METHODS: This was an analysis of data from the PAN-COVID registry (January 1st to July 25th 2020), which includes pregnancies with suspected or confirmed maternal SARS-CoV-2 infection at any stage in pregnancy, and the AAP SONPM National Perinatal COVID-19 registry (April 4th to August 8th 2020), which includes pregnancies with positive maternal testing for SARS-CoV-2 from 14 days before delivery to 3 days after delivery. The registries collected data on maternal, fetal, perinatal and neonatal outcomes. The PAN-COVID results are presented both overall for pregnancies with suspected or confirmed SARS-CoV-2 infection and separately in those with confirmed infection. RESULTS: We report on 4005 pregnant women with suspected or confirmed SARS-CoV-2 infection (1606 from PAN-COVID and 2399 from AAP SONPM). For obstetric outcomes, in PAN-COVID overall, those with confirmed infection in PAN-COVID and AAP SONPM, respectively, maternal death occurred in 0.5%, 0.5% and 0.2% of cases, early neonatal death in 0.2%, 0.3% and 0.3% of cases and stillbirth in 0.5%, 0.6% and 0.4% of cases. Delivery was pre-term (<37 weeks' gestation) in 12.0% of all women in PAN-COVID, in 16.2% of those women with confirmed infection in PAN-COVID and in 15.7% of women in AAP SONPM. Extremely preterm delivery (< 27 weeks' gestation) occurred in 0.5% of cases in PAN-COVID and 0.3% in AAP SONPM. Neonatal SARS-CoV-2 infection was reported in 0.8% of all deliveries in PAN-COVID, in 2.0% in those with confirmed infection in PAN-COVID and in 1.8% in AAP SONPM; the proportions of neonates tested were 9.5%, 20.7% and 87.2%, respectively. The rates of a SGA neonate were 8.2% in PAN-COVID overall, 9.7% in those with confirmed infection and 9.6% in AAP SONPM. Mean gestational age adjusted birth-weight z-scores were -0.03 in PAN-COVID and -0.18 in AAP SONPM. CONCLUSIONS: The findings from the UK and US registries of pregnancies with SARS-CoV-2 infection were remarkably concordant. Preterm delivery affected a higher proportion of women than expected based on historical and contemporaneous national data. The proportions of pregnancies affected by stillbirth, a small for gestational age infant or early neonatal death were comparable to those in historical and contemporaneous UK and US data. Although maternal death was uncommon, the rate was higher than expected based on UK and US population data, which is likely explained by under-ascertainment of women affected by milder or asymptomatic infection in pregnancy in the PAN-COVID study although not in the AAP SONPM study. The data presented support strong guidance for enhanced precautions to prevent SARS-CoV-2 infection in pregnancy, particularly in the context of increased risks of preterm delivery and maternal mortality, and for priority vaccination of women planning pregnancy. This article is protected by copyright. All rights reserved
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