Comparison of fluorescence-based techniques for the quantification of particle-induced hydroxyl radicals

<p>Abstract</p> <p>Background</p> <p>Reactive oxygen species including hydroxyl radicals can cause oxidative stress and mutations. Inhaled particulate matter can trigger formation of hydroxyl radicals, which have been implicated as one of the causes of particulate-induced lung disease. The extreme reactivity of hydroxyl radicals presents challenges to their detection and quantification. Here, three fluorescein derivatives [aminophenyl fluorescamine (APF), amplex ultrared, and dichlorofluorescein (DCFH)] and two radical species, proxyl fluorescamine and tempo-9-ac have been compared for their usefulness to measure hydroxyl radicals generated in two different systems: a solution containing ferrous iron and a suspension of pyrite particles.</p> <p>Results</p> <p>APF, amplex ultrared, and DCFH react similarly to the presence of hydroxyl radicals. Proxyl fluorescamine and tempo-9-ac do not react with hydroxyl radicals directly, which reduces their sensitivity. Since both DCFH and amplex ultrared will react with reactive oxygen species other than hydroxyl radicals and another highly reactive species, peroxynitite, they lack specificity.</p> <p>Conclusion</p> <p>The most useful probe evaluated here for hydroxyl radicals formed from cell-free particle suspensions is APF due to its sensitivity and selectivity.</p

Experiences of a commercial weight-loss programme after primary care referral: a qualitative study.

BACKGROUND: Referral to a commercial weight-loss programme is a cost-effective intervention that is already used within the NHS. Qualitative research suggests this community-based, non-medical intervention accords with participants' view of weight management as a lifestyle issue. AIM: To examine the ways in which participants' attitudes and beliefs about accessing a commercial weight management programme via their doctor relate to their weight-loss experience, and to understand how these contextual factors influence motivation and adherence to the intervention. DESIGN AND SETTING: A qualitative study embedded in a randomised controlled trial evaluating primary care referral to a commercial weight-loss programme in adults who are overweight or obese in England. The study took place from June-September 2013. METHOD: Twenty-nine participants (body mass index [BMI] ≥28 kg/m(2); age ≥18 years), who took part in the WRAP (Weight Loss Referrals for Adults in Primary Care) trial, were recruited at their 3-month assessment appointment to participate in a semi-structured interview about their experience of the intervention and weight management more generally. Interviews were audiorecorded, transcribed verbatim, and analysed inductively using a narrative approach. RESULTS: Although participants view the lifestyle-based, non-medical commercial programme as an appropriate intervention for weight management, the referral from the GP and subsequent clinical assessments frame their experience of the intervention as medically pertinent with clear health benefits. CONCLUSION: Referral by the GP and follow-up assessment appointments were integral to participant experiences of the intervention, and could be adapted for use in general practice potentially to augment treatment effects

Role of pyrite in formation of hydroxyl radicals in coal: possible implications for human health

BACKGROUND: The harmful effects from inhalation of coal dust are well-documented. The prevalence of lung disease varies by mining region and may, in part, be related to regional differences in the bioavailable iron content of the coal. Pyrite (FeS(2)), a common inorganic component in coal, has been shown to spontaneously form reactive oxygen species (ROS) (i.e., hydrogen peroxide and hydroxyl radicals) and degrade nucleic acids. This raises the question regarding the potential for similar reactivity from coal that contains pyrite. Experiments were performed to specifically evaluate the role of pyrite in coal dust reactivity. Coal samples containing various amounts of FeS(2 )were compared for differences in their generation of ROS and degradation of RNA. RESULTS: Coals that contain iron also show the presence of FeS(2), generate ROS and degrade RNA. Coal samples that do not contain pyrite do not produce ROS nor degrade RNA. The concentration of generated ROS and degradation rate of RNA both increase with greater FeS(2 )content in the coals. CONCLUSION: The prevalence of coal workers' pneumoconiosis can be correlated to the amount of FeS(2 )in the coals. Considering the harmful effects of generation of ROS by inhaled particles, the results presented here show a possible mechanism whereby coal samples may contribute to CWP. This suggests that the toxicity of coal may be explained, in part, by the presence of FeS(2)

Assignment of the Human and Mouse Prion Protein Genes to Homologous Chromosomes

Purified preparations of scrapie prions contain one major macromolecule, designated prion protein (PrP). Genes encoding PrP are found in normal animals and humans but not within the infectious particles. The PrP gene was assigned to human chromosome 20 and the corresponding mouse chromosome 2 using somatic cell hybrids. In situ hybridization studies mapped the human PrP gene to band 20p12→pter. Our results should lead to studies of genetic loci syntenic with the PrP gene, which may play a role in the pathogenesis of prion diseases or other degenerative neurologic disorders

The Universal Form of Treatment Options (UFTO) as an alternative to Do Not Attempt Cardiopulmonary Resuscitation (DNACPR) orders: a mixed methods evaluation of the effects on clinical practice and patient care.

AIMS: To determine whether the introduction of the Universal Form of Treatment Options (the UFTO), as an alternative approach to Do Not Attempt Cardiopulmonary Resuscitation (DNACPR) orders, reduces harms in patients in whom a decision not to attempt cardiopulmonary resuscitation (CPR) was made, and to understand the mechanism for any observed change. METHODS: A mixed-methods before-and-after study with contemporaneous case controls was conducted in an acute hospital. We examined DNACPR (103 patients with DNACPR orders in 530 admissions) and UFTO (118 decisions not to attempt resuscitation in 560 admissions) practice. The Global Trigger Tool was used to quantify harms. Qualitative interviews and observations were used to understand mechanisms and effects. RESULTS: RATE OF HARMS IN PATIENTS FOR WHOM THERE WAS A DOCUMENTED DECISION NOT TO ATTEMPT CPR WAS REDUCED: Rate difference per 1000 patient-days was 12.9 (95% CI: 2.6-23.2, p-value=0.01). There was a difference in the proportion of harms contributing to patient death in the two periods (23/71 in the DNACPR period to 4/44 in the UFTO period (95% CI 7.8-36.1, p-value=0.006). Significant differences were maintained after adjustment for known confounders. No significant change was seen on contemporaneous case control wards. Interviews with clinicians and observation of ward practice revealed the UFTO helped provide clarity of goals of care and reduced negative associations with resuscitation decisions. CONCLUSIONS: Introducing the UFTO was associated with a significant reduction in harmful events in patients in whom a decision not to attempt CPR had been made. Coupled with supportive qualitative evidence, this indicates the UFTO improved care for this vulnerable group. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN85474986 UK Comprehensive Research Network Portfolio 7932

Making Sense of a New Transport System: An Ethnographic Study of the Cambridgeshire Guided Busway

An increase in public transport use has the potential to contribute to improving population health, and there is growing interest in innovative public transport systems. Yet how new public transport infrastructure is experienced and integrated (or not) into daily practice is little understood. We investigated how the Cambridgeshire Guided Busway, UK, was used and experienced in the weeks following its opening, using the method of participant observation (travelling on the busway and observing and talking to passengers) and drawing on Normalization Process Theory to interpret our data. Using excerpts of field notes to support our interpretations, we describe how the ease with which the new transport system could be integrated into existing daily routines was important in determining whether individuals would continue to use it. It emerged that there were two groups of passengers with different experiences and attitudes. Passengers who had previously travelled frequently on regular bus services did not perceive the new system to be an improvement; consequently, they were frustrated that it was differentiated from and not coherent with the regular system. In contrast, passengers who had previously travelled almost exclusively by car appraised the busway positively and perceived it to be a novel and superior form of travel. Our rich qualitative account highlights the varied and creative ways in which people learn to use new public transport and integrate it into their everyday lives. This has consequences for the introduction and promotion of future transport innovations. It is important to emphasise the novelty of new public transport, but also the ways in which its use can become ordinary and routine. Addressing these issues could help to promote uptake of other public transport interventions, which may contribute to increasing physical activity and improving population health. © 2013 Jones et al

Weight loss referrals for adults in primary care (WRAP) : Protocol for a multi-centre randomised controlled trial comparing the clinical and cost-effectiveness of primary care referral to a commercial weight loss provider for 12 weeks, referral for 52 weeks, and a brief self-help intervention [ISRCTN82857232]

Background: Recent trials demonstrate the acceptability and short term efficacy of primary care referral to a commercial weight loss provider for weight management. Commissioners now need information on the optimal duration of intervention and the longer term outcomes and cost effectiveness of such treatment to give best value for money. Methods/Design. This multicentre, randomised controlled trial with a parallel design will recruit 1200 overweight adults (BMI ≥28 kg/m2) through their primary care provider. They will be randomised in a 2:5:5 allocation to: Brief Intervention, Commercial Programme for 12 weeks, or Commercial Programme for 52 weeks. Participants will be followed up for two years, with assessments at 0, 3, 12 and 24 months. The sequential primary research questions are whether the CP interventions achieve significantly greater weight loss from baseline to 12 months than BI, and whether CP52 achieves significantly greater weight loss from baseline to 12 months than CP12. The primary outcomes will be an intention to treat analysis of between treatment differences in body weight at 12 months. Clinical effectiveness will be also be assessed by measures of weight, fat mass, and blood pressure at each time point and biochemical risk factors at 12 months. Self-report questionnaires will collect data on psychosocial factors associated with adherence, weight-loss and weight-loss maintenance. A within-trial and long-term cost-effectiveness analysis will be conducted from an NHS perspective. Qualitative methods will be used to examine the participant experience. Discussion. The current trial compares the clinical and cost effectiveness of referral to a commercial provider with a brief intervention. This trial will specifically examine whether providing longer weight-loss treatment without altering content or intensity (12 months commercial referral vs. 12 weeks) leads to greater weight loss at one year and is sustained at 2 years. It will also evaluate the relative cost-effectiveness of the three interventions. This study has direct implications for primary care practice in the UK and will provide important information to inform the decisions of practitioners and commissioners about service provision

Infinite factorization of multiple non-parametric views

Combined analysis of multiple data sources has increasing application interest, in particular for distinguishing shared and source-specific aspects. We extend this rationale of classical canonical correlation analysis into a flexible, generative and non-parametric clustering setting, by introducing a novel non-parametric hierarchical mixture model. The lower level of the model describes each source with a flexible non-parametric mixture, and the top level combines these to describe commonalities of the sources. The lower-level clusters arise from hierarchical Dirichlet Processes, inducing an infinite-dimensional contingency table between the views. The commonalities between the sources are modeled by an infinite block model of the contingency table, interpretable as non-negative factorization of infinite matrices, or as a prior for infinite contingency tables. With Gaussian mixture components plugged in for continuous measurements, the model is applied to two views of genes, mRNA expression and abundance of the produced proteins, to expose groups of genes that are co-regulated in either or both of the views. Cluster analysis of co-expression is a standard simple way of screening for co-regulation, and the two-view analysis extends the approach to distinguishing between pre- and post-translational regulation

Evaluating the use of 3'-(p-Aminophenyl) fluorescein for determining the formation of highly reactive oxygen species in particle suspensions

<p>Abstract</p> <p>Background</p> <p>Given the importance of highly reactive oxygen species (hROS) as reactants in a wide range of biological, photochemical, and environmental systems there is an interest in detection and quantification of these species. The extreme reactivity of the hROS, which includes hydroxyl radicals, presents an analytical challenge. 3'-(<it>p</it>-Aminophenyl) fluorescein (APF) is a relatively new probe used for measuring hROS. Here, we further evaluate the use of APF as a method for the detection of hydroxyl radicals in particle suspensions.</p> <p>Results</p> <p>Particle-generated hROS can be quantified with an estimated detection limit of 50 nM. Measurements of hROS in two National Institute of Standards and Technology (NIST 2709 and 2710) soil suspensions and a pyrite suspension show non-linear particle dose-response curves for hROS generation. APF can also be used in solutions containing no dissolved molecular oxygen (O₂) to determine the role of O₂in the formation of hROS. Results confirm that O₂is mechanistically important in the formation of hROS by dissolved ferrous iron and in pyrite suspensions.</p> <p>Conclusion</p> <p>Given the non-linear dose-response curves for particle generation of hROS, we recommend using several particle loadings in experiments aimed to compare particles for their hROS generation potential. The method presented here is specific to hROS and simple to perform. The analysis can be conducted in mobile labs as only basic laboratory equipment is required.</p