Directed intermittent search for a hidden target on a dendritic tree

Motivated by experimental observations of active (motor-driven) intracellular transport in neuronal dendrites, we analyze a stochastic model of directed intermittent search on a tree network. A particle injected from the cell body or soma into the primary branch of the dendritic tree randomly switches between a stationary search phase and a mobile nonsearch phase that is biased in the forward direction. A (synaptic) target is presented somewhere within the tree, which the particle can locate if it is within a certain range and in the searching phase. We approximate the moment generating function using Green’s function methods. The moment generating function is then used to compute the hitting probability and conditional mean first passage time to the target. We show that in contrast to a previously explored finite interval case, there is a range of parameters for which a bidirectional search strategy is more efficient than a unidirectional one in finding the target

Increasing condom use in heterosexual men: development of a theory-based interactive digital intervention

Increasing condom use to prevent sexually transmitted infections is a key public health goal. Interventions are more likely to be effective if they are theory- and evidence-based. The Behaviour Change Wheel (BCW) provides a framework for intervention development. To provide an example of how the BCW was used to develop an intervention to increase condom use in heterosexual men (the MenSS website), the steps of the BCW intervention development process were followed, incorporating evidence from the research literature and views of experts and the target population. Capability (e.g. knowledge) and motivation (e.g. beliefs about pleasure) were identified as important targets of the intervention. We devised ways to address each intervention target, including selecting interactive features and behaviour change techniques. The BCW provides a useful framework for integrating sources of evidence to inform intervention content and deciding which influences on behaviour to target

The RAPID-CTCA trial (Rapid Assessment of Potential Ischaemic Heart Disease with CTCA) - a multicentre parallel-group randomised trial to compare early computerised tomography coronary angiography versus standard care in patients presenting with suspected or confirmed acute coronary syndrome: study protocol for a randomised controlled trial.

BACKGROUND: Emergency department attendances with chest pain requiring assessment for acute coronary syndrome (ACS) are a major global health issue. Standard assessment includes history, examination, electrocardiogram (ECG) and serial troponin testing. Computerised tomography coronary angiography (CTCA) enables additional anatomical assessment of patients for coronary artery disease (CAD) but has only been studied in very low-risk patients. This trial aims to investigate the effect of early CTCA upon interventions, event rates and health care costs in patients with suspected/confirmed ACS who are at intermediate risk. METHODS/DESIGN: Participants will be recruited in about 35 tertiary and district general hospitals in the UK. Patients ≥18 years old with symptoms with suspected/confirmed ACS with at least one of the following will be included: (1) ECG abnormalities, e.g. ST-segment depression >0.5 mm; (2) history of ischaemic heart disease; (3) troponin elevation above the 99(th) centile of the normal reference range or increase in high-sensitivity troponin meeting European Society of Cardiology criteria for 'rule-in' of myocardial infarction (MI). The early use of ≥64-slice CTCA as part of routine assessment will be compared to standard care. The primary endpoint will be 1-year all-cause death or recurrent type 1 or type 4b MI at 1 year, measured as the time to such event. A number of secondary clinical, process and safety endpoints will be collected and analysed. Cost effectiveness will be estimated in terms of the lifetime incremental cost per quality-adjusted life year gained. We plan to recruit 2424 (2500 with ~3% drop-out) evaluable patients (1212 per arm) to have 90% power to detect a 20% versus 15% difference in 1-year death or recurrent type 1 MI or type 4b MI, two-sided p < 0.05. Analysis will be on an intention-to-treat basis. The relationship between intervention and the primary outcome will be analysed using Cox proportional hazard regression adjusted for study site (used to stratify the randomisation), age, baseline Global Registry of Acute Coronary Events score, previous CAD and baseline troponin level. The results will be expressed as a hazard ratio with the corresponding 95% confidence intervals and p value. DISCUSSION: The Rapid Assessment of Potential Ischaemic Heart Disease with CTCA (RAPID-CTCA) trial will recruit 2500 participants across about 35 hospital sites. It will be the first study to investigate the role of CTCA in the early assessment of patients with suspected or confirmed ACS who are at intermediate risk and including patients who have raised troponin measurements during initial assessment. TRIAL REGISTRATION: ISRCTN19102565 . Registered on 3 October 2014. ClinicalTrials.gov: NCT02284191

Overweight and lifestyle behaviors of low socioeconomic elementary school children in Buenos Aires

<p>Abstract</p> <p>Background</p> <p>There is growing interest in understanding the role that lifestyle behaviors play in relation to children's weight status. The objective of the study was to determine the association between children s BMI and dietary practices and maternal BMI.</p> <p>Methods</p> <p>330 students (168M) aged 8.9 + 2 y from 4 suburban Buenos Aires elementary schools, and their mothers aged 36.2 + 7 y were examined between April and September 2007. Mothers were asked about their children s lifestyle. Data included parental education levels socioeconomic status, mothers and children s BMI, and Tanner stage.</p> <p>Results</p> <p>All families were in the low socio-economic class. 79% of parents had an elementary education or less. 61 (18.5%) of children were obese (OB) (BMI>95%ile per CDC norms), and 53 (16.1%) overweight (OW) (BMI>85<95%ile). 103 (31.2%) of mothers were OB (BMI>30 kg/m2), and102 (30.9%) OW (BMI>25<30). 63% the children were pre-pubertal. 40% had a TV set in their bedroom. 13% of the children skipped breakfast and only 38% watched TV ≤2 hours daily, as recommended. Multiple logistic regression analysis showed a positive association between children s OW/OB and drinking sweetened beverages (OR = 1.24; 95% CI, 1.02–1.52), TV viewing (OR = 1.30; 95% CI,1.05–1.62), and maternal BMI (OR: 1.07; 95% CI,1.02–1.12), and a negative association with eating breakfast (OR = 0.43; 95% CI, 0.19–0.97) adjusted for fruit and vegetables consumption, milk consumption, maternal educational level and socioeconomic class.</p> <p>Conclusion</p> <p>Our results suggest that TV viewing, drinking sweet beverages, skipping breakfast, and maternal BMI are important predictive variables for childhood OW/OB.</p

South Asians living in the UK and adherence to coronary heart disease medication: a mixed- method study.

Background The prevalence of coronary heart disease amongst South Asian population in the UK is higher compared to the general population. Objective This study sought to investigate beliefs and experiences of South Asian patients regarding coronary heart disease and medication taking behaviour. Setting A London Heart Attack Centre. Methods This mixed method study is part of an original pilot randomised study on 71 patients involving a pharmacy-led intervention to improve medication adherence in coronary heart disease patients. South Asian patients from the randomised study took part in qualitative semi-structured telephone interviews. Both South Asian and non-South Asian patients completed the questionnaire about adherence and beliefs regarding medicines using Morisky Scale and the Belief About Medicines Questionnaire-Specific at 2 weeks, 3 and 6 months. Outcome Patients' beliefs about coronary heart disease and medication adherence. Results Seventeen South Asian patients and 54 non-South Asian patients took part. Qualitative data from 14 South Asian patients showed that while some attributed coronary heart disease to genetic, family history for their illness, others attributed it to their dietary patterns and 'god's will' and that little could be done to prevent further episodes of coronary heart disease. On the Belief About Medicines Questionnaire-Specific in South Asian patients, beliefs about necessity of medicines outweighed concerns. South Asian patients (n = 17) showed a similar pattern of adherence compared to non-Asian patients (n = 54). Adherence decreased with time in both populations, adherence measured by Morisky Scale. Conclusion South Asian patients in this study often attributed coronary heart disease to additional causes besides the known risk factors. Future studies on their understanding of the importance of cultural context in their attitudes to prevention and lived experience of the disease is warranted

Triple-gated motion and blood pool clearance corrections improve reproducibility of coronary 18F-NaF PET

PurposeTo improve the test-retest reproducibility of coronary plaque 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) uptake measurements.MethodsWe recruited 20 patients with coronary artery disease who underwent repeated hybrid PET/CT angiography (CTA) imaging within 3&nbsp;weeks. All patients had 30-min PET acquisition and CTA during a single imaging session. Five PET image-sets with progressive motion correction were reconstructed: (i) a static dataset (no-MC), (ii) end-diastolic PET (standard), (iii) cardiac motion corrected (MC), (iv) combined cardiac and gross patient motion corrected (2 × MC) and, (v) cardiorespiratory and gross patient motion corrected (3 × MC). In addition to motion correction, all datasets were corrected for variations in the background activities which are introduced by variations in the injection-to-scan delays (background blood pool clearance correction, BC). Test-retest reproducibility of PET target-to-background ratio (TBR) was assessed by Bland-Altman analysis and coefficient of reproducibility.ResultsA total of 47 unique coronary lesions were identified on CTA. Motion correction in combination with BC improved the PET TBR test-retest reproducibility for all lesions (coefficient of reproducibility: standard = 0.437, no-MC = 0.345 (27% improvement), standard&nbsp;+&nbsp;BC = 0.365 (20% improvement), no-MC + BC = 0.341 (27% improvement), MC + BC = 0.288 (52% improvement), 2 × MC + BC = 0.278 (57% improvement) and 3 × C + BC = 0.254 (72% improvement), all p &lt; 0.001). Importantly, in a sub-analysis of 18F-NaF-avid lesions with gross patient motion &gt;&nbsp;10&nbsp;mm following corrections, reproducibility was improved by 133% (coefficient of reproducibility: standard = 0.745, 3 × MC = 0.320).ConclusionJoint corrections for cardiac, respiratory, and gross patient motion in combination with background blood pool corrections markedly improve test-retest reproducibility of coronary 18F-NaF PET

The risk of child and adolescent overweight is related to types of food consumed

<p>Abstract</p> <p>Background/Aims</p> <p>To investigate the association between the risk of overweight and the consumption of food groups in children and adolescents.</p> <p>Methods</p> <p>We studied 1764 healthy children and adolescents (age 6-19y) attending 16 Seventh-Day Adventist schools and 13 public schools using a 106-item non-quantitative food frequency questionnaire from the late 1980 Child-Adolescent Blood Pressure Study. Logistic regression models were used to compute the risk of overweight according to consumption of grains, nuts, vegetables, fruits, meats/fish/eggs, dairy, and, low nutrient-dense foods (LNDF).</p> <p>Results</p> <p>The frequency of consumption of grains, nuts, vegetables and LNDF were inversely related to the risk of being overweight and dairy increased the risk. Specifically, the odds ratio (95% CI) for children in the highest quartile or tertile of consumption compared with the lowest quartile or tertile were as follows: grains 0.59(0.41-0.83); nuts 0.60(0.43-0.85); vegetables 0.67(0.48-0.94); LNDF 0.43(0.29-0.63); and, dairy 1.36(0.97, 1.92).</p> <p>Conclusion</p> <p>The regular intake of specific plant foods may prevent overweight among children and adolescents.</p