Actin Flows Mediate a Universal Coupling between Cell Speed and Cell Persistence

Cell movement has essential functions in development, immunity, and cancer. Various cell migration patterns have been reported, but no general rule has emerged so far. Here, we show on the basis of experimental data in vitro and in vivo that cell persistence, which quantifies the straightness of trajectories, is robustly coupled to cell migration speed. We suggest that this universal coupling constitutes a generic law of cell migration, which originates in the advection of polarity cues by an actin cytoskeleton undergoing flows at the cellular scale. Our analysis relies on a theoretical model that we validate by measuring the persistence of cells upon modulation of actin flow speeds and upon optogenetic manipulation of the binding of an actin regulator to actin filaments. Beyond the quantitative prediction of the coupling, the model yields a generic phase diagram of cellular trajectories, which recapitulates the full range of observed migration patterns

The Correlates of Leisure Time Physical Activity among an Adults Population from Southern Taiwan

<p>Abstract</p> <p>Background</p> <p>Assessing the correlates of practicing physical activity during leisure time is important with regard to planning and designing public health strategies to increase beneficial behaviors among adult populations. Although the importance of leisure time physical activity (LTPA) is highlighted in many Western countries, there are not many publications on physical activity patterns, and even less on their correlates, in non-Western societies. The goal of this study was thus to explore the determinants influencing adults' leisure time physical activity (LTPA) in a city in southern Taiwan.</p> <p>Methods</p> <p>A cross-sectional population-based study was conducted in 2007, using a standardized questionnaire. Energy expenditure was dichotomized into two groups based on the recommended levels of moderate physical activity from LTPA: ≥10 or < 10 MET·hr·wk^-1. Logistic regression analyses were applied to the results.</p> <p>Results</p> <p>A total of 762 subjects with valid data took part in the study (mean age 53.8 ± 13.8 years). In multivariate logistic regression analysis, we found the following results: Age was positively associated with LTPA. Adults with stronger perceived convenience of exercise facilities (OR = 2.04; 95%CI = 1.28-3.24) and past exercise experience in school (OR = 1.86; 95%CI= 1.19-2.91) participated in more LTPA. Subjects with more general social support (OR = 1.66;95%CI = 1.13-2.44), greater knowledge about the health benefits of exercise (OR = 1.85;95%CI = 1.25-2.74), more sports media consumption (OR = 1.94;95%CI = 1.26-2.98), and higher self-efficacy (OR = 3.99;95%CI = 2.67-5.97) were more likely to engage in LTPA. Further analysis comparing different sources of social support showed only social support from friends had a significant positive association (OR = 1.73;95%CI = 1.14-2.63) with increased LTPA.</p> <p>Conclusions</p> <p>LTPA in southern city of Taiwan showed some unique associations with age, socioeconomic status and media consumption that are not commonly reported in the Western World and similar associations with regards to psychosocial correlates of LTPA participation. Further studies from developing countries are warranted to highlight culture-specific differences in physical activity participation.</p

Observation of a J^PC = 1-+ exotic resonance in diffractive dissociation of 190 GeV/c pi- into pi- pi- pi+

The COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the pi- pi- pi+ final state using a 190 GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of 420000 events taken at values of the squared 4-momentum transfer t' between 0.1 and 1 GeV^2/c^2. The well-known resonances a1(1260), a2(1320), and pi2(1670) are clearly observed. In addition, the data show a significant natural parity exchange production of a resonance with spin-exotic quantum numbers J^PC = 1-+ at 1.66 GeV/c^2 decaying to rho pi. The resonant nature of this wave is evident from the mass-dependent phase differences to the J^PC = 2-+ and 1++ waves. From a mass-dependent fit a resonance mass of 1660 +- 10+0-64 MeV/c^2 and a width of 269+-21+42-64 MeV/c^2 is deduced.Comment: 7 page, 3 figures; version 2 gives some more details, data unchanged; version 3 updated authors, text shortened, data unchange

Male pygmy hippopotamus influence offspring sex ratio

Pre-determining fetal sex is against the random and equal opportunity that both conceptus sexes have by nature. Yet, under a wide variety of circumstances, populations shift their birth sex ratio from the expected unity. Here we show, using fluorescence in situ hybridization, that in a population of pygmy hippopotamus (Choeropsis liberiensis) with 42.5% male offspring, males bias the ratio of X- and Y-chromosome-bearing spermatozoa in their ejaculates, resulting in a 0.4337±0.0094 (mean±s.d.) proportion of Y-chromosome-bearing spermatozoa. Three alternative hypotheses for the shifted population sex ratio were compared: female counteract male, female indifferent, or male and female in agreement. We conclude that there appears little or no antagonistic sexual conflict, unexpected by prevailing theories. Our results indicate that males possess a mechanism to adjust the ratio of X- and Y-chromosome-bearing spermatozoa in the ejaculate, thereby substantially expanding currently known male options in sexual conflict

Genetic and Chemical Modifiers of a CUG Toxicity Model in Drosophila

Non-coding CUG repeat expansions interfere with the activity of human Muscleblind-like (MBNL) proteins contributing to myotonic dystrophy 1 (DM1). To understand this toxic RNA gain-of-function mechanism we developed a Drosophila model expressing 60 pure and 480 interrupted CUG repeats in the context of a non-translatable RNA. These flies reproduced aspects of the DM1 pathology, most notably nuclear accumulation of CUG transcripts, muscle degeneration, splicing misregulation, and diminished Muscleblind function in vivo. Reduced Muscleblind activity was evident from the sensitivity of CUG-induced phenotypes to a decrease in muscleblind genetic dosage and rescue by MBNL1 expression, and further supported by the co-localization of Muscleblind and CUG repeat RNA in ribonuclear foci. Targeted expression of CUG repeats to the developing eye and brain mushroom bodies was toxic leading to rough eyes and semilethality, respectively. These phenotypes were utilized to identify genetic and chemical modifiers of the CUG-induced toxicity. 15 genetic modifiers of the rough eye phenotype were isolated. These genes identify putative cellular processes unknown to be altered by CUG repeat RNA, and they include mRNA export factor Aly, apoptosis inhibitor Thread, chromatin remodelling factor Nurf-38, and extracellular matrix structural component Viking. Ten chemical compounds suppressed the semilethal phenotype. These compounds significantly improved viability of CUG expressing flies and included non-steroidal anti-inflammatory agents (ketoprofen), muscarinic, cholinergic and histamine receptor inhibitors (orphenadrine), and drugs that can affect sodium and calcium metabolism such as clenbuterol and spironolactone. These findings provide new insights into the DM1 phenotype, and suggest novel candidates for DM1 treatments

Referrals to a regional allergy clinic - an eleven year audit

<p>Abstract</p> <p>Background</p> <p>Allergy is a serious and apparently increasing public health problem yet relatively little is known about the types of allergy seen in routine tertiary practice, including their spatial distribution, co-occurrence or referral patterns. This study reviewed referrals over an eleven year period to a regional allergy clinic that had a well defined geographical boundary. For those patients confirmed as having an allergy we explored: (i) differences over time and by demographics, (ii) types of allergy, (iii) co-occurrence, and (iv) spatial distributions.</p> <p>Methods</p> <p>Data were extracted from consultant letters to GPs, from September 1998 to September 2009, for patients confirmed as having an allergy. Other data included referral statistics and population data by postcode. Simple descriptive analysis was used to describe types of allergy. We calculated 11 year standardised morbidity ratios for postcode districts and checked for spatial clustering. We present maps showing 11 year rates by postcode, and 'difference' maps which try to separate referral effect from possible environmental effect.</p> <p>Results</p> <p>Of 5778 referrals, 961 patients were diagnosed with an allergy. These were referred by a total of 672 different GPs. There were marked differences in referral patterns between GP practices and also individual GPs. The mean age of patients was 35 and there were considerably more females (65%) than males. Airborne allergies were the most frequent (623), and there were very high rates of co-occurrence of pollen, house dust mite, and animal hair allergies. Less than half (410) patients had a food allergy, with nuts, fruit, and seafood being the most common allergens. Fifteen percent (142) had both a food and a non-food allergy. Certain food allergies were more likely to co-occur, for example, patients allergic to dairy products were more likely to be allergic to egg.</p> <p>There were age differences by types of allergy; people referred with food allergies were on average 5 years younger than those with other allergies, and those allergic to nuts were much younger (26 Vs 38) than those with other food allergies.</p> <p>There was clear evidence for spatial clustering with marked clustering around the referral hospital. However, the geographical distribution varied between allergies; airborne (particularly pollen allergies) clustered in North Dartmoor and Exmoor, food allergies (particularly nut allergies) in the South Hams, and on small numbers, some indication of seafood allergy in the far south west of Cornwall and in the Padstow area.</p> <p>Conclusions</p> <p>This study shows marked geographical differences in allergy referrals which are likely to reflect a combination of environmental factors and GP referral patterns. The data suggest that GPs may benefit from education and ongoing decision support and be supported by public education on the nature of allergy. It suggests further research into what happens to patients with allergy where there has been low use of tertiary services and further research into cross-reactivity and co-occurrence, and spatial distribution of allergy.</p

Laboratorial approach in the diagnosis of food allergy

OBJCTIVE: Review the available laboratory tests used to assist in the diagnosis of IgE-mediated and non-IgE-mediated food allergy. DATA SOURCES: Papers in English and Portuguese published in PubMed and Embase, in the last ten years. Terms searched were food allergy, diagnose and laboratory, isolated and/or associated. DATA SYNTHESIS: The diagnostic approach to food allergy reactions includes a good medical history, laboratory studies, elimination diets and blinded food challenges. More recently, the use of a quantitative measurement of food-specific IgE antibodies has been shown to be more predictive of symptomatic IgE-mediated food allergy. Food-specific IgE serum levels exceeding the diagnostic values indicate that the patient is greater than 95% likely to experience an allergic reaction if he/she ingests the specific food. Such decision point values have been defined just for some foods and inconsistent results were obtained when allergy to the same food was studied in different centers. Food challenges, in particular the double-blind placebo-controlled food challenge (DBPCFC), represent the most reliable way to establish or rule out food hypersensitivity. CONCLUSIONS: A number of recent developments are improving the predictive value of some laboratory tests for the diagnosis of food allergies. However, to date, no in-vitro or in-vivo test shows full correlation with clinical food allergy and the DBPCFC remains the gold standard for the definitive diagnosis of specific food allergies. There is an urgent need for new and fundamentally improved diagnostic approaches, which must be validated in patients with food allergy confirmed by a positive DBPCFC.OBJETIVO: Revisar os exames laboratoriais disponíveis utilizados no diagnóstico da alergia alimentar mediada ou não por IgE. FONTES DE DADOS: Artigos publicados em base de dados PubMed e Embase (língua inglesa e portuguesa) nos últimos dez anos. As palavras-chave utilizadas como fonte de busca foram alergia alimentar, diagnóstico e laboratório, isolados e/ou associados. SÍNTESE DOS DADOS: A abordagem diagnóstica das reações alérgicas a alimentos inclui história clínica completa, estudos laboratoriais, dietas de eliminação e desencadeamentos cegos com alimentos. Recentemente, a medida quantitativa de anticorpos IgE específicos a alimentos tem mostrado ser mais preditiva de alergia alimentar sintomática mediada por IgE. Níveis séricos de IgE específica a alimento que excedam os valores diagnósticos indicam que o paciente tem chance maior que 95% de apresentar uma reação alérgica se ingerir o alimento em questão. Estes valores de decisão foram definidos para alguns alimentos e resultados inconsistentes são obtidos ao se estudar diferentes populações. Os desencadeamentos com alimento, especialmente o duplo-cego controlado por placebo (DADCCP), representa a maneira mais confiável de estabelecer ou descartar o diagnóstico de hipersensibilidade alimentar. CONCLUSÕES: Número crescente de aquisições tem melhorado o valor preditivo de alguns testes laboratoriais empregados no diagnóstico de alergias alimentares. Entretanto, até hoje, não há teste in vitro ou in vivo que mostre correlação completa com a clínica da alergia alimentar. O DADCCP continua sendo o padrão-ouro no diagnóstico definitivo de alergia alimentar específica. São necessárias, urgentemente, novas abordagens diagnósticas válidadas em pacientes com alergia alimentar confirmada por DADCCP positivo.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PediatriaUNIFESP-EPM Departamento de PediatriaUniversidade de São Paulo Faculdade de Medicina Departamento de PediatriaUniversidade Federal da Bahia Departamento de PediatriaUNIFESP-EPMUniversidade Federal do Paraná Departamento de PediatriaUNIFESP, EPM, Depto. de PediatriaUNIFESP, EPM Depto. de PediatriaUNIFESP, EPMSciEL

Patterns in sedentary and exercise behaviors and associations with overweight in 9–14-year-old boys and girls - a cross-sectional study.

BACKGROUND: Before starting interventions addressing energy-balance related behaviors, knowledge is needed about the prevalence of sedentary behaviors and low physical exercise, their interrelationships, possible gender differences. Therefore this study aimed to describe gender differences in sedentary and physical exercise behaviors and their association with overweight status in children from nine European countries. Additionally, to identify clusters of children sharing the same pattern regarding sedentary and physical exercise behavior and compare these groups regarding overweight status. METHODS: Cross-sectional study among 11-year-old children in nine countries (n = 12538). Self-administered questionnaires assessed the time spent on TV viewing during dinner and during the day, PC use and on physical exercise. The parents reported children's weight and height. Descriptive statistics, cluster analyses, and logistic regression analyses were used for data analyses. RESULTS: Boys spent more time on sedentary behaviors but also more on physical exercise than girls. High TV viewing and low exercise behavior independently increased the risk of being overweight. Based on the behaviors, five clusters were identified. Among boys, clear associations with being overweight were found, with the most unhealthy behavior pattern having the highest risks of being overweight. Among girls, high TV viewers and high PC users had increased risk of being overweight. In girls sedentary behaviors seemed more important than physical exercise with regard to overweight status. CONCLUSION: Despite selective non-response on BMI and reliance on self-reports, the associations between clusters and overweight in boys were clear, and differences between boys and girls regarding the behaviors and risks for overweight are noteworthy. These differences need to be considered when developing tailored intervention strategies for prevention of overweight