Daniel Lewis

Incompatibility, stamen movement and pollen economy in a heterostyled tropical forest tree, Cratoxylum formosum (Guttiferae)

Cratoxylum formosum shows all the classical features of a distylic species. The two types are: long-styled plants with short stamens and small pollen grains and short-styled plants with long stamens and large pollen grains. Compatible pollinations are only between the two types; incompatible pollen tubes are inhibited in the style. A significant morphological feature distinguishes Cratoxylum from distylic plants in other families. Instead of having a small number of anthers making well separated narrow discs in the two types, Cratoxylum has many anthers (144) and they are arranged on staminal bundles that produce long cylinders of anthers that partially occupy similar height zones in the two types of flower. A novel method of separation of the two height zones is achieved by the bending of the stamens of the long-styled type when the flower opens, which converts the cylinder to a narrow disc of anthers at the same height as the ‘short’ stigma. The bending coincides with anther dehiscence and is slightly later than the first daily insect visitation. The anthers return to the upright position later in the day, when the pollination is complete. There was a 20-fold difference between the amounts of pollen deposited on the two types of stigmas. The ‘long’ stigmas received 1200 pollen grains per flower, in the ratio of 46 ‘long’ to 54 ‘short’, which is close to the ratio of two types of pollen produced in the population. This random deposition of pollen on ‘long’ stigmas is, however, more than adequate for the 36 seeds produced per flower. ‘Short’ stigmas received only 64 pollen grains per flower, in the ratio of 90 ‘long’ to 10 ‘short’, and several flowers had below the critical level of 36 compatible pollen grains for full seed production. Pollen loads of the pollinating bee, Apis javana, consisted of ‘long’ and ‘short’ pollen on the thorax in the ratio found on the ‘long’ stigma, and on the head of the bee in a ratio close to the 9:1 found on the ‘short ’ stigma. The corbicular loads reflected accurately the pollen of the tree in which the bee was caught. For Cratoxylum the accurate positioning of the anthers of the long-styled plant in relation to the visiting bees head was an important evolutionary step in the effective pollination of the short-styled form, which, at least in this species, is one critical and highly selected feature of the system.

Carbon in airway macrophages from children with asthma

Background Airway macrophage (AM) phagocytosis is impaired in severe asthma. Prostaglandin (PG) E2 and D2 are increased in severe asthma and suppress AM phagocytic function in vitro. In this study, we sought evidence for PG-mediated impairment of phagocytosis of inhalable carbonaceous particulate matter (PM) by AM in children with severe asthma compared with mild asthmatics and healthy controls. Methods AM were obtained from children with asthma and healthy controls using induced sputum. AM carbon area (μm2) was assessed by image analysis. In a subgroup of asthmatics, urinary PGE2 and PGD2 metabolites were measured by high-performance liquid chromatography, and PM exposure at the home address was modelled. Phagocytosis of PM by human monocyte-derived macrophages and rat AM was assessed in vitro by image analysis. Results AM carbon was 51% lower in children with moderate-to-severe asthma (n=36) compared with mild asthmatics (n=12, p<0.01) and healthy controls (n=47, p<0.01). There was no association between modelled PM exposure and AM carbon in 33 asthmatics who had a urine sample, but there was an inverse association between AM carbon and urinary metabolites of PGE2 and D2 (n=33, rs=−0.40, p<0.05, and rs=−0.44, p<0.01). PGE2 10−6 M, but not PGD2 10−6 M, suppressed phagocytosis of PM10 by human macrophages in vitro (p<0.05 vs control). PGE2 10−6 M also suppressed phagocytosis of PM10 by rat AM in vitro (p<0.01 vs control). Conclusions Phagocytosis of inhaled carbonaceous PM by AMs is impaired in severe asthma. PGE2 may contribute to impaired AM phagocytic function in severe asthma.

Association between neighbourhood walkability and metabolic risk factors influenced by physical activity: a cross-sectional study of adults in Toronto, Canada

Objective To determine whether neighbourhood walkability is associated with clinical measures of obesity, hypertension, diabetes and dyslipidaemia in an urban adult population. Design Observational cross-sectional study. Setting Urban primary care patients. Participants 78 023 Toronto residents, aged 18 years and over, who were formally rostered or had at least 2 visits between 2012 and 2014 with a primary care physician participating in the University of Toronto Practice Based Research Network (UTOPIAN), within the Canadian Primary Care Sentinel Surveillance Network (CPCSSN). Main outcome measures Differences in average body mass index (BMI), systolic and diastolic blood pressure, fasting blood glucose, haemoglobin A1c (HbA1C), total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein and triglyceride between residents in the highest versus the lowest quartile of neighbourhood walkability, as estimated using multivariable linear regression models and stratified by age. Outcomes were objectively measured and were retrieved from primary care electronic medical records. Models adjusted for age, sex, smoking, medications, medical comorbidities and indices of neighbourhood safety and marginalisation. Results Compared with those in the lowest walkability quartile, individuals in the highest quartile had lower mean BMI (−2.64 kg/m2, 95% CI −2.98 to −2.30; p<0.001), systolic blood pressure (−1.35 mm Hg, 95% CI −2.01 to −0.70; p<0.001), diastolic blood pressure (−0.60 mm Hg, 95% CI 1.06 to −0.14; p=0.010) and HbA1c (−0.063%, 95% CI −0.11 to −0.021; p=0.003) and higher mean HDL (0.052 mmol/L, 95% CI 0.029 to 0.075; p<0.001). In age-stratified analyses, differences in the mean BMI were consistently observed for adults aged 18 to under 40 (−4.44 kg/m2, 95% CI −5.09 to −3.79; p<0.001), adults aged 40–65 (−2.74 kg/m2, 95% CI −3.24 to −2.23; p<0.001) and adults aged over 65 (−0.87 kg/m2, 95% CI −1.48 to −0.26; p=0.005). Conclusions There was a clinically meaningful association between living in the most walkable neighbourhoods and having lower BMI in adults of all ages.

Individual socio-demographic factors and perceptions of the environment as determinants of inequalities in adolescent physical and psychological health: the Olympic Regeneration in East London (ORiEL) study

BackgroundPopulations living in urban areas experience greater health inequalities as well as higher absolute burdens of illness. It is well-established that a range of social and environmental factors determine these differences. Less is known about the relative importance of these factors in determining adolescent health within a super diverse urban context.MethodsA cross-sectional sample of 3,105 adolescent participants aged 11 to 12 were recruited from 25 schools in the London boroughs of Newham, Tower Hamlets, Hackney and Barking & Dagenham. Participants completed a pseudo-anonymised paper-based questionnaire incorporating: the Warwick-Edinburgh Mental Well-being Scale used for assessing positive mental well-being, the Short Moods and Feelings Questionnaire based on the DSM III-R criteria for assessment of depressive symptoms, the Youth-Physical Activity Questionnaire and a self-assessment of general health and longstanding illness. Prevalence estimates and unadjusted linear models estimate the extent to which positive well-being scores and time spent in physical/sedentary activity vary by socio-demographic and environmental indicators. Logistic regression estimated the unadjusted odds of having fair/(very)poor general health, a long standing illness, or depressive symptoms. Fully adjusted mixed effects models accounted for clustering within schools and for all socio-demographic and environmental indicators.ResultsCompared to boys, girls had significantly lower mental well-being and higher rates of depressive symptoms, reported fewer hours physically active and more hours sedentary, and had poorer general health after full adjustment. Positive mental well-being was significantly and positively associated with family affluence but the overall relationship between mental health and socioeconomic factors was weak. Mental health advantage increased as positive perceptions of the neighbourhood safety, aesthetics, walkability and services increased. Prevalence of poor health varied by ethnic group, particularly for depressive symptoms, general health and longstanding illness suggesting differences in the distribution of the determinants of health across ethnic groups.ConclusionsDuring adolescence perceptions of the urban physical environment, along with the social and economic characteristics of their household, are important factors in explaining patterns of health inequality.

Patient Mobility for Elective Secondary Health Care Services in Response to Patient Choice Policies A Systematic Review

Our review establishes the empirical evidence for patient mobility for elective secondary care services in countries that allow patients to choose their health care provider. PubMed and Embase were searched for relevant articles between 1990 and 2015. Of 5,994 titles/abstracts reviewed, 26 studies were included. The studies used three main methodological models to establish mobility. Variation in the extent of patient mobility was observed across the studies. Mobility was positively associated with lower waiting times, indicators of better service quality, and access to advanced technology. It was negatively associated with advanced age or lower socioeconomic backgrounds. From a policy perspective we demonstrate that a significant proportion of patients are prepared to travel beyond their nearest provider for elective services. As a consequence, some providers are likely to be “winners” and others “losers,” which could result in overall decreased provider capacity or inefficient utilization of existing services. Equity also remains a key concern.

Everyone was looking at you smiling: East London residents' experiences of the 2012 Olympics and its legacy on the social determinants of health.

Mega-sporting event regeneration, as a specific approach to urban renewal, uses impending host-city status as a catalyst for revitalisation and has the potential to improve health both through addressing deprivation and by promoting increased sport and physical activity among the host-citys population. This qualitative study explored how hosting of the London 2012 Games impacted upon the way East London residents perceived and experienced the social determinants of health in their local neighbourhood. We conducted narrative family interviews, go-along interviews and video focus group workshops with 66 Newham residents, aged 12-55 years, immediately after the Games. A narrative analytic approach examined accounts of health and wellbeing experiences in terms of neighbourhood change and the spectacle of the Games. Participants of this qualitative study generally welcomed the respite and the unexpected chance to live in a cleaner, safer and more unified environment. However, this positivity was underscored by an acute awareness that this was a very temporary situation and one that was intended to support the event rather than residents.

A health and social legacy for East London: Narratives of 'problem' and 'solution' around London 2012

Policies and programmes that tackle neighbourhood deprivation have long been a feature of urban policy in the UK and elsewhere. Large-scale urban regeneration and neighbourhood renewal programmes have been deployed as the primary vehicle to improve the health and life chances of residents of deprived neighbourhoods. Often these areas have a long history of efforts at regeneration and redevelopment and, over time, have become labelled as ‘problem areas’ in need of constant intervention. The bid for the London 2012 Olympic and Paralympic Games was successful partly due to its promise to deliver a lasting health and social legacy by using the Games as a driver of regeneration in East London. Despite limited evidence for the effectiveness of such an approach, regeneration schemes tied to sporting events have emerged as popular strategies through which cities strive to enhance their urban fabric. Running through the core of the London 2012 bid was a discourse of East London as a ‘problem’ in need of a regeneration ‘solution’ that the Olympics uniquely could deliver. As a result, a wider narrative of East London was generated: as unhealthy; mired in poverty; desperate for jobs; with an inadequate and outdated built environment. The Olympic legacy was thus positioned as a unique once-in-a-lifetime solution ‘accelerating’ regeneration in East London, and delivering substantive change that either might not have happened, or would otherwise have taken decades. Through documentary analysis of published Government policy documents for the period 2002-2011, we demonstrate how the ‘problem’ of East London was used as political justification for London 2012. We argue that the Olympic legacy was deliberately positioned in neoliberal terms in order to justify substantial economic investment by the UK government and suit the needs of the International Olympic Committee. Finally, whilst acknowledging that regeneration may indeed result, we also speculate on the potential legacy and possible challenges for the people in East London left by this neoliberal and entrepreneurial strategy.

Population-level Spatial Access to Prehospital Care by the National Ambulance Service in Ghana

Abstract Background: Conditions requiring emergency treatment disproportionately affect low- and middle-income countries (LMICs), where there is often insufficient prehospital care capacity. To inform targeted prehospital care development in Ghana, we aimed to describe spatial access to formal prehospital care services and identify ambulance stations for capacity expansion. Methods: Cost distance methods were used to evaluate areal and population-level access to prehospital care within 30 and 60 minutes of each of the 128 ambulance stations in Ghana. With network analysis methods, a two-step floating catchment area model was created to identify district-level variability in access. Districts without NAS stations within their catchment areas were identified as candidates for an additional NAS station. Additionally, five candidate stations for capacity expansion (e.g., addition of an ambulance) were then identified through iterative simulations that were designed to identify the stations that had the greatest influence on the access scores of the ten lowest access districts. Results: Following NAS inception, the proportion of Ghanas landmass serviceable within 60 minutes of a station increased from 8.7 to 59.4% from 2004 to 2014, respectively. Over the same time period, the proportion of the population with access to the NAS within 60-minutes increased from 48% to 79%. The two-step floating catchment area model identified considerable variation in district-level access scores, which ranged from 0.05 to 2.43 ambulances per 100,000 persons (median 0.45; interquartile range 0.23-0.63). Seven candidate districts for NAS station addition and five candidate NAS stations for capacity expansion were identified. The addition of one ambulance to each of the five candidate stations improved access scores in the ten lowest access districts by a total 0.22 ambulances per 100,000 persons. Conclusions: The NAS in Ghana has expanded its population-level spatial access to the majority of the population; however, access inequality exists in both rural and urban areas that can be improved by increasing station capacity or adding additional stations. Geospatial methods to identify access inequities and inform service expansion might serve as a model for other LMICs attempting to understand and improve formal prehospital care services.

The relationship between dietary quality and the local food environment differs according to level of educational attainment: A cross-sectional study

There is evidence that food outlet access differs according to level of neighbourhood deprivation but little is known about how individual circumstances affect associations between food outlet access and diet. This study explored the relationship between dietary quality and a measure of overall food environment, representing the balance between healthy and unhealthy food outlet access in individualised activity spaces. Furthermore, this study is the first to assess effect modification of level of educational attainment on this relationship. A total of 839 mothers with young children from Hampshire, United Kingdom (UK) completed a cross-sectional survey including a 20-item food frequency questionnaire to measure diet and questions about demographic characteristics and frequently visited locations including home, children’s centre, general practitioner, work, main food shop and physical activity location. Dietary information was used to calculate a standardised dietary quality score for each mother. Individualised activity spaces were produced by creating a 1000m buffer around frequently visited locations using ArcGIS. Cross-sectional observational food outlet data were overlaid onto activity spaces to derive an overall food environment score for each mother. These scores represented the balance between healthy and unhealthy food outlets using weightings to characterise the proportion of healthy or unhealthy foods sold in each outlet type. Food outlet access was dominated by the presence of unhealthy food outlets; only 1% of mothers were exposed to a healthy overall food environment in their daily activities. Level of educational attainment moderated the relationship between overall food environment and diet (mid vs low, p = 0.06; high vs low, p = 0.04). Adjusted stratified linear regression analyses showed poorer food environments were associated with better dietary quality among mothers with degrees (β = -0.02; 95%CI: -0.03, -0.001) and a tendency toward poorer dietary quality among mothers with low educational attainment, however this relationship was not statistically significant (β = 0.01; 95%CI: -0.01, 0.02). This study showed that unhealthy food outlets, like takeaways and convenience stores, dominated mothers’ food outlet access, and provides some empirical evidence to support the concept that individual characteristics, particularly educational attainment, are protective against exposure to unhealthy food environments. Improvements to the imbalance of healthy and unhealthy food outlets through planning restrictions could be important to reduce dietary inequalities.

Determinants of Patient Mobility for Prostate Cancer Surgery: A Population-based Study of Choice and Competition

Many countries have introduced policies that enable patients to select a health care provider of their choice with the aim of improving the quality of care. However, there is little information about the drivers or the impact of patient mobility. Using administrative hospital data (n=19256) we analysed the mobility of prostate cancer patients who had radical surgery in England between 2010 and 2014. Our analysis, using geographic information systems and multivariable choice modelling, found that 33·5% (n=6465) of men bypassed their nearest prostate cancer surgical centre. Travel time had a strong impact on where patients moved to but was less of a factor for men who were younger, fitter, and more affluent (p always < 0.001). Men were more likely to move to hospitals that provided robotic prostate cancer surgery (odds ratio: 1.42, p<0.001) and to hospitals that employed surgeons with a strong media reputation (odds ratio: 2.18, p<0.001). Patient mobility occurred in the absence of validated measures of the quality of care, instead influenced by the adoption of robotic surgery and the reputation of individual clinicians. National policy based on patient choice and provider competition may have had a negative impact on equality of access, service capacity, and health system efficiency. PATIENT SUMMARY In this study, we assessed the reasons why men would choose to have prostate cancer surgery at a centre other than their nearest. We found that in England men were attracted to centres that carried out robotic surgery and employed surgeons with a national reputation.