67 research outputs found
Intrinsic high aerobic capacity protects against lipid induced hepatic insulin resistance [abstract]
Hepatic steatosis is commonly linked to hepatic insulin resistance. However, recent studies have found that increased hepatic triacylglycerol (TAG) accumulation is not always associated with impaired hepatic insulin signaling, leading to a hypothesis that partitioning of lipids into TAG in the liver matched with high rates of fatty acid oxidation (FAO) under high lipid exposure conditions may protect against hepatic insulin resistance. We examined this hypothesis in the livers of high and low capacity running (HCR/LCR) rats which were created by artificial selection based on differences in intrinsic aerobic capacity
Evaluation of a novel intervention providing insight into the tobacco industry to prevent the uptake of smoking in school-aged children: a mixed-methods study
Objectives: Evidence from the US Truth® campaign suggests that interventions focusing on tobacco industry practices and ethics may be effective in preventing youth smoking uptake. We developed, piloted and evaluated a school-based intervention based on this premise.
Methods: Exploratory study Students in Years 7–8 (aged 11–13) in two UK schools received Operation Smoke Storm, comprising three 50-minute classroom-based sessions in Year 7, an accompanying family booklet and a 1-hour classroom-based booster session in Year 8. We compared the risk and odds of ever smoking and susceptibility to smoking in Year 8 students in study schools post-intervention compared with students in control schools. Focus groups and interviews with students, teachers and parents evaluated the acceptability of the intervention.
Results: In intervention schools the combined prevalence of ever smoking and susceptibility increased from 18.2% in Year 7 to 33.8% in Year 8. There was no significant difference in the odds of a Year 8 student in an intervention school being an ever smoker or susceptible never smoker compared with controls [adjusted OR 1.28, 95%CI 0.83-1.97, p=0.263] and no significant difference in the odds of ever smoking (aOR 0.82, 95%CI 0.42-1.58, p=0.549). Teachers highlighted differences by academic ability in how well the messages presented were understood. Use of the family component was low but was received positively by parents who engaged with it.
Conclusions: Operation Smoke Storm is an acceptable resource for delivering smoking-prevention education but it does not appear to have reduced smoking and susceptibility
Translational Approach to Examine the Importance of Aerobic Fitness on Nonalcoholic Fatty Liver Disease [abstract]
Comparative Medicine - OneHealth and Comparative Medicine Poster Session.Low cardiorespiratory fitness, independent of physical activity levels, is the best predictor of early mortality and is linked to type 2 diabetes and CVD. In the absence of exercise training, it is believed that genetic inheritance accounts for up to 70% of the variation in intrinsic aerobic fitness. Recent cross-sectional reports in humans also have linked low aerobic fitness with nonalcoholic fatty liver disease (NAFLD). NAFLD, fatty liver not due to alcohol consumption, encompasses a gamut of liver maladaptations and is a primary cause of chronic liver disease and liver-related morbidity and mortality. NAFLD occurs in ~30% of US adults, 75-100% of obese and extremely obese individuals, and is considered the hepatic component of the metabolic syndrome. Despite the recent observations in humans between low fitness and NAFLD, there is a paucity of mechanistic information detailing this link. In order to address this important clinical problem, we have developed an interdisciplinary team across multiple institutions and fields of study and have taken a translational approach, employing both novel whole animal model studies and isolated primary hepatocyte cell culture experiments, to gain mechanistic insight into the human observational studies. We have utilized a novel rat model in which rats are artificially selected over several generations for high and low intrinsic endurance capacity, resulting in high capacity runners (HCR) with high aerobic fitness and low capacity runners (LCR) with significantly lower aerobic fitness (Science, 307:418-20, 2005). These rats display contrasting phenotypes without the influence of exercise training, making them an excellent model to mechanistically assess the role of aerobic fitness on NAFLD. Utilizing this model, we have provided the first mechanistic evidence that the LCR rats have reduced hepatic mitochondrial content and oxidative capacity, increased hepatic de novo lipogenic profiles, and develop hepatic steatosis with progression to greater fibrosis and apoptosis compared to the HCR rats. The LCR rats also are unable to maintain systemic insulin sensitivity following exposure to high-fat feeding. However, since it is impossible to completely eliminate the influence of peripheral factors on liver metabolism, we have subsequently isolated primary hepatocytes from HCR and LCR rats. We have observed a similar phenotype in the primary hepatocytes from LCR animals, with significant reductions in fatty acid oxidation and the inability to maintain insulin signaling in response to lipid exposure compared with HCR hepatocytes. These findings have important clinical implications, as low aerobic fitness due to physical inactivity and/or genetic inheritability may lead to increased susceptibility to NAFLD, and suggest that the clinical measurement of aerobic fitness may serve as a valuable prognostic tool. We are currently conducting a human clinical trial to assess the efficacy of exercise in improving aerobic fitness and reducing NAFLD, and because exercise is the proven method to increase aerobic fitness, it should remain the cornerstone therapy for fatty liver disease
Yorkshire Enhanced Stop Smoking study (YESS): a protocol for a randomised controlled trial to evaluate the effect of adding a personalised smoking cessation intervention to a lung cancer screening programme
Introduction:Integration of smoking cessation (SC) into lung cancer screening (LCS) is essential to optimise clinical and cost effectiveness. The most effective way to use this “teachable moment” is unclear. The Yorkshire Enhanced Stop Smoking study (YESS) will measure the effectiveness of a SC service integrated within the Yorkshire Lung Screening Trial (YLST) and will test the efficacy of a personalised SC intervention, incorporating incidental findings detected on the low-dose computed tomography scan performed as part of YLST.Methods and analysis: Unless explicitly declined, all smokers enrolled in YLST will see a Smoking Cessation Practitioner (SCP) at baseline and receive smoking cessation support over 4-weeks comprising behavioural support, pharmacotherapy and/or a commercially available e-cigarette. Eligible smokers will be randomised (1:1 in permuted blocks of random size up to size 6) to receive either an enhanced, personalised smoking cessation support package, including CT scan images, or continued SBP. Anticipated recruitment is 1040 smokers (January 2019 – December 2020). The primary objective is to measure 7-day point prevalent carbon monoxide (CO) validated smoking cessation after 3-months. Secondary outcomes include CO validated cessation at 4-weeks and 12-months, self-reported continuous cessation at 4-weeks, 3-month and 12-months, attempts to quit smoking and changes in psychological variables, including perceived risk of lung cancer, motivation to quit smoking tobacco, confidence and efficacy beliefs (self and response) at all follow up points. A process evaluation will explore under which circumstances and on which groups the intervention works best, test intervention fidelity and theory test the mechanisms of intervention impact.Ethics and dissemination: This study has been approved by the East Midlands-Derby Research Ethics Committee (18/EM/0199) and the Health Research Authority/Health and Care Research Wales. Results will be disseminated through publication in peer-reviewed scientific journals, presentation at conferences and via the YLST website. Trial registration number: ISRCTN63825779; NIH ClinicalTrials.gov NCT0375011
A qualitative evaluation of a novel intervention using insight into tobacco industry tactics to prevent the uptake of smoking in school-aged children
Background: Evidence from the US Truth campaign suggests that interventions focusing on tobacco industry tactics can be effective in preventing smoking uptake by children. Operation Smoke Storm is the first school-based intervention based on this premise and comprises three classroom sessions in which students act as secret agents uncovering tobacco industry tactics through videos, quizzes, discussions, and presentations. We report a qualitative evaluation of its acceptability.
Methods: We conducted eight focus groups with 79 students aged 11-12 who participated in Operation Smoke Storm at two UK schools in Autumn 2013, and 20 interviews with teachers who delivered the intervention. These were digitally audio-recorded, transcribed verbatim and analysed using the framework method.
Results: Students enjoyed the secret agent scenario and reported acquiring new knowledge about smoking and the tobacco industry, which seemed to strengthen their aversion to smoking. Teachers felt confident delivering the ‘off the shelf’ resource, although they would have welcomed more background information about the topic and guidance on steering discussions. Teachers highlighted a need for the resource to be flexible and not dependent on lesson length, teacher confidence, or expertise. Students and teachers endorsed the idea of developing a booster component for older students and supported the development of printed information complementing the resource to encourage parents to support their child not to smoke.
Conclusions: These findings demonstrate that Operation Smoke Storm can be delivered by teachers to raise awareness about smoking-related issues. The ideas and issues raised are now being used to improve and extend the resource for further evaluation
The Atacama Cosmology Telescope: Two-Season ACTPol Spectra and Parameters
We present the temperature and polarization angular power spectra measured by
the Atacama Cosmology Telescope Polarimeter (ACTPol). We analyze night-time
data collected during 2013-14 using two detector arrays at 149 GHz, from 548
deg of sky on the celestial equator. We use these spectra, and the spectra
measured with the MBAC camera on ACT from 2008-10, in combination with Planck
and WMAP data to estimate cosmological parameters from the temperature,
polarization, and temperature-polarization cross-correlations. We find the new
ACTPol data to be consistent with the LCDM model. The ACTPol
temperature-polarization cross-spectrum now provides stronger constraints on
multiple parameters than the ACTPol temperature spectrum, including the baryon
density, the acoustic peak angular scale, and the derived Hubble constant.
Adding the new data to planck temperature data tightens the limits on damping
tail parameters, for example reducing the joint uncertainty on the number of
neutrino species and the primordial helium fraction by 20%.Comment: 23 pages, 25 figure
Yorkshire Enhanced Stop Smoking (YESS) study: a protocol for a randomised controlled trial to evaluate the effect of adding a personalised smoking cessation intervention to a lung cancer screening programme
Introduction:Integration of smoking cessation (SC) into lung cancer screening (LCS) is essential to optimise clinical and cost effectiveness. The most effective way to use this “teachable moment” is unclear. The Yorkshire Enhanced Stop Smoking study (YESS) will measure the effectiveness of a SC service integrated within the Yorkshire Lung Screening Trial (YLST) and will test the efficacy of a personalised SC intervention, incorporating incidental findings detected on the low-dose computed tomography scan performed as part of YLST.Methods and analysis: Unless explicitly declined, all smokers enrolled in YLST will see a Smoking Cessation Practitioner (SCP) at baseline and receive smoking cessation support over 4-weeks comprising behavioural support, pharmacotherapy and/or a commercially available e-cigarette. Eligible smokers will be randomised (1:1 in permuted blocks of random size up to size 6) to receive either an enhanced, personalised smoking cessation support package, including CT scan images, or continued SBP. Anticipated recruitment is 1040 smokers (January 2019 – December 2020). The primary objective is to measure 7-day point prevalent carbon monoxide (CO) validated smoking cessation after 3-months. Secondary outcomes include CO validated cessation at 4-weeks and 12-months, self-reported continuous cessation at 4-weeks, 3-month and 12-months, attempts to quit smoking and changes in psychological variables, including perceived risk of lung cancer, motivation to quit smoking tobacco, confidence and efficacy beliefs (self and response) at all follow up points. A process evaluation will explore under which circumstances and on which groups the intervention works best, test intervention fidelity and theory test the mechanisms of intervention impact.Ethics and dissemination: This study has been approved by the East Midlands-Derby Research Ethics Committee (18/EM/0199) and the Health Research Authority/Health and Care Research Wales. Results will be disseminated through publication in peer-reviewed scientific journals, presentation at conferences and via the YLST website. Trial registration number: ISRCTN63825779; NIH ClinicalTrials.gov NCT0375011
Rats selectively bred for low aerobic capacity have reduced hepatic mitochondrial oxidative capacity and susceptibility to hepatic steatosis and injury
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65411/1/jphysiol.2009.169060.pd
Heregulin β1 drives gefitinib-resistant growth and invasion in tamoxifen-resistant MCF-7 breast cancer cells
Introduction
Resistance to anti-epidermal growth factor receptor (anti-EGFR) therapies is an emerging clinical problem. The efficacy of anti-EGFR therapies can be influenced by the presence of heregulins (HRGs), which can bind erbB3/4 receptors and can activate alternative signalling pathways. In the present study we have examined whether HRG signalling can circumvent EGFR blockade in an EGFR-positive tamoxifen-resistant MCF-7 (Tam-R) breast cancer cell line.
Methods
Tam-R cells, incubated with the selective EGFR tyrosine kinase inhibitor gefitinib ('Iressa', ZD1839), were exposed to HRGβ1 and the effects on erbB receptor dimerization profiles and on activation of associated downstream signalling components were assessed by immunoprecipitation, western blotting and immunocytochemistry. The effects of HRGβ1 on gefitinib-treated Tam-R cell growth and invasion were also examined, and HRGβ1 expression levels were assessed in breast cancer tissue by immunohistochemistry to address the potential clinical relevance of such a resistance mechanism.
Results
In Tam-R cells, HRGβ1 promoted erbB3/erbB2 and erbB3/EGFR heterodimerization, promoted ERK1/2 and AKT pathway activation and increased cell proliferation and invasion. Gefitinib prevented HRGβ1-driven erbB3/EGFR heterodimerization, ERK1/2 activation and Tam-R cell proliferation, but HRGβ1-driven erbB3/erbB2 heterodimerization, AKT activation and Tam-R cell invasion were maintained. A combination of gefitinib and the phosphatidylinositol 3-kinase inhibitor LY294002 effectively blocked HRGβ1-mediated intracellular signalling activity, growth and invasion in Tam-R cells. Similarly, targeting erbB2 with trastuzumab in combination with gefitinib in Tam-R cells reduced HRGβ1-induced erbB2 and ERK1/2 activity; however, HRGβ1-driven AKT activity and cell growth were maintained while cell invasion was significantly enhanced with this combination. In clinical tissue all samples demonstrated cytoplasmic tumour epithelial HRGβ1 protein staining, with expression correlating with EGFR positivity and activation of both AKT and ERK1/2.
Conclusion
HRGβ1 can overcome the inhibitory effects of gefitinib on cell growth and invasion in Tam-R cells through promotion of erbB3/erbB2 heterodimerization and activation of the phosphatidylinositol 3-kinase/AKT signalling pathway. This may have implications for the effectiveness of anti-EGFR therapies in breast cancer as HRGβ1 is enriched in many EGFR-positive breast tumours
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