Automatic detection of beating cilia with frequencies estimations

International audienceMuco-ciliary clearance is the airway first mechanism of defence against environmental attacks such as microorganisms or pollution. Cilia motility impairment can be either of genetic (primary ciliary dyskinesia) or acquired origin (environmental attacks), entailing chronic diseases. It is of interest for practitioners to evaluate cilia beating frequency easily, robustly and reliably. As yet, no fully automatized method is available. 2 Methods Ciliated cells were sampled in patients by brushing nasal mucosa and cilia beating was recorded using high speed video microscopy. We first estimated and removed the sensor pattern. We then stabilized the sequence assuming rigid transforms. We retained only the moving parts of the sequence and, after deblurring, characterized and segmented the moving parts in several regions of interest. The frequency was estimated for each region

Repeated coronary artery occlusions during routine balloon angioplasty do not induce myocardial preconditioning in humans

AbstractObjectives.The purpose of the present study was to assess whether brief, repeated coronary artery occlusions during balloon angioplasty induce a myocardial ischemic protective effect.Background.In animals, brief coronary artery occlusions preceding a more prolonged occlusion result in reduced infarct size. Whether myocardial protection against ischemia could also occur in humans during angioplasty remains controversial.Methods.Thirteen patients with a proximal left anterior descending coronary artery stenosis with no angiographic collateral circulation underwent percutaneous transluminal coronary artery balloon angioplasty. Three 120-s balloon inflations separated by a 5-min equilibrium period were performed. For each inflation, intracoronary ST segment modifications, septal wall thickening (M-mode echocardiography), left ventricular pressures and time derivatives were measured at baseline and at 30, 60 a d 90 s after balloon inflation and 120 s after balloon deflation.Results.Intracoronary electrocardiographic analysis showed that the time course of the maximal ST segment elevation was identical at each inflation, as were wall motion changes assessed by the decrease in septal wall thickening. For the first and last inflations, peak positive dP/dt decreased significantly by 13 ± 9% (mean ± SD) and 14 ± 13%, whereas peak negative dP/dt increased by 23 ± 15% and 22 ± 10%, respectively (all p < 0.01 from baseline values). The relaxation time constant, tau, was altered similarity during the different inflations, from 44 ± 6 to 74 ± 13 ms and from 57 ± 13 to 77 ± 13 ms (all p < 0.001) for the first and last inflations, respectively. Left ventricular endiastolic pressure increased to the same level after each inflation. In contrast to other hemodynamic variables, tau and left ventricular end-diastolic pressure did not return to baseline values in between the inflations, which may be due to myocardial stunning.Conclusions.In patients with proximal left anterior descending coronary artery stenosis and no evidence of collateral circulation, brief periods of ischemia, such as those used during routine coronary balloon angioplasty, do not provide any protection against myocardial ischemia

Detection of African swine fever virus genotype XV in a sylvatic cycle in Saadani National Park, Tanzania

This research article was published by Wiley Online Library, 2020African swine fever (ASF) is a severe haemorrhagic disease of domestic pigs caused by ASF virus (ASFV). ASFV is transmitted by soft ticks (Ornithodoros moubata complex group) and by direct transmission. In Africa, ASF is maintained in transmission cycles of asymptomatic infection involving wild suids, mainly warthogs (Phacochoerus afri canus). ASF outbreaks have been reported in many parts of Tanzania; however, active surveillance has been limited to pig farms in a few geographical locations. There is an information gap on whether and where the sylvatic cycle may occur independently of domestic pigs. To explore the existence of a sylvatic cycle in Saadani National Park in Tanzania, blood and serum samples were collected from 19 warthogs se lected using convenience sampling along vehicle-accessible transects within the na tional park. The ticks were sampled from warthog burrows. Blood samples and ticks were subjected to ASFV molecular diagnosis (PCR) and genotyping, and warthog sera were subjected to serological (indirect ELISA) testing for ASFV antibody detection. All warthog blood samples were PCR-negative, but 16/19 (84%) of the warthog sera were seropositive by ELISA confirming exposure of warthogs to ASFV. Of the ticks sampled, 20/111 (18%) were positive for ASFV by conventional PCR. Sequencing of the p72 virus gene fragments showed that ASF viruses detected in ticks belonged to genotype XV. The results confirm the existence of a sylvatic cycle of ASFV in Saadani National Park, Tanzania, that involves ticks and warthogs independent of domestic pigs. Our findings suggest that genotype XV previously reported in 2008 in Tanzania is likely to be widely distributed and involved in both wild and domestic infection cycles. Whole-genome sequencing and analysis of the ASFV genotype XV circulating in Tanzania is recommended to determine the phylogeny of the viruses

African swine fever virus (ASFV): biology, genomics and genotypes circulating in sub-Saharan Africa

African swine fever (ASF) is a highly infectious and fatal haemorrhagic disease of pigs that is caused by a complex DNA virus of the genus Asfivirus and Asfarviridae African suids family. The disease is among the most devastating pig diseases worldwide including Africa. Although the disease was first reported in the 19th century, it has continued to spread in Africa and other parts of the world. Globally, the rising demand for pork and concomitant increase in transboundary movements of pigs and pork products is likely to increase the risk of transmission and spread of ASF and pose a major challenge to the pig industry. Different genotypes of the ASF virus (ASFV) with varying virulence have been associated with different outbreaks in several countries in sub-Saharan Africa (SSA) and worldwide, and understanding genotype circulation will be important for ASF prevention and control strategies. ASFV genotypes unique to Africa have also been reported in SSA. This review briefly recounts the biology, genomics and genotyping of ASFV and provides an account of the different genotypes circulating in SSA. The review also highlights prevention, control and progress on vaccine development and identifies gaps in knowledge of ASFV genotype circulation in SSA that need to be addressed

Ett köpcentrums attraktionskraft : Vilka faktorer är väsentliga vid konsumentens val av köpcentrum?

Shoppning har i allt större utsträckning blivit ett fritidsnöje bland konsumenter idag, detta tillsammans med den stora framväxten utav köpcentrum de senaste årtiondena gör det allt viktigare för köpcentrums ansvariga att identifiera och belysa faktorer och tillvägagångssätt för köpcentrumets attraktionskraft. Uppsatsen har som mål att ta fram de faktorer som är mest avgörande för ett köpcentrums attraktionskraft ur konsumenternas perspektiv. Syftet är att ta fram de faktorer som ökar attraktionskraften genom Mikael Hernants sexhörning och genom teorin om de fyra p: na. Vi använder också Kirkup och Rafiqs teorier om betydelsen av en bra mix av hyresgäster i ett köpcentrum. Valet utav undersökning blev en kvalitativ undersökning som går på djupet, den undersökningsmetod som var mest ändamålsenlig för vår uppsats var fokusgrupper. I fokusgrupperna diskuterades det om olika faktorer som bidrog till ett köpcentrums attraktionskraft. Grupperna delade vi in åldersvis mellan 15-25 år, 26-49 år och 50-70 år för att få ett så brett perspektiv som möjligt. Detta gjorde vi också med tanke på att vi troligen skulle få olika värderingar av de olika åldersindelningarna. Det som kan sammanfattas av undersökningen var att mixen av butiker var den huvudsakliga och avgörande faktorn för samtliga grupper. Läget av, tillgängligheten och förbindelser till köpcentrumet var också en starkt bidragande faktor. Främsta anledningen att besöka externa köpcentrum och köpcentrum på annan ort var den sociala aspekten av shopping där man ser det som en socialaktivitet där man umgås med vänner och familj. Medans ett lokalt köpcentrum besöks utav skäl som tillgänglighet och smidigheten att shoppa. Framstående från de olika fokusgrupperna var förutom de ovanstående faktorerna att ungdomarna tyckte det var viktigt att det fanns möjlighet att koppla av med en fika eller sitta ner och konversera på bänkar eller andra sittplatser. Medan för de äldre var det viktigt att det var behagligt och lätt att shoppa. I analysdelen analyserar vi genomförligt den teori vi har införskaffat med det empiriska resultatet vi fick fram i vår undersökning. Slutligen kommer vi att presentera de slutsatser vi har kommit fram till för att besvara vår problemformulering på ett så tydligt sätt som möjligt

Cell mechanics of alveolar epithelial cells (AECs) and macrophages (AMs).

International audienceCell mechanics provides an integrated view of many biological phenomena which are intimately related to cell structure and function. Because breathing constitutes a sustained motion synonymous with life, pulmonary cells are normally designed to support permanent cyclic stretch without breaking, while receiving mechanical cues from their environment. The authors study the mechanical responses of alveolar cells, namely epithelial cells and macrophages, exposed to well-controlled mechanical stress in order to understand pulmonary cell response and function. They discuss the principle, advantages and limits of a cytoskeleton-specific micromanipulation technique, magnetic bead twisting cytometry, potentially applicable in vivo. They also compare the pertinence of various models (e.g., rheological; power law) used to extract cell mechanical properties and discuss cell stress/strain hardening properties and cell dynamic response in relation to the structural tensegrity model. Overall, alveolar cells provide a pertinent model to study the biological processes governing cellular response to controlled stress or strain

Racial Differences in 30-Day Reintubation After Head and Neck Surgery

Background This study aimed to examine the association of race and ethnicity with 30-day unplanned reintubation following head and neck surgery. Methodology A retrospective analysis of head and neck surgery patients aged greater than or equal to 18 years was extracted from the American College of Surgeons National Surgical Quality Improvement Program database from 2015 to 2020. Patient demographics, comorbidities, and 30-day reintubation were included in the analysis. Pearson's chi-square and independent samples t-test were used to compare reintubation cohorts. Multivariable logistic regression was used to identify the association of race and ethnicity with 30-day reintubation. Results Of the total 108,442 head and neck surgery cases included, 74.9% of patients were non-Hispanic White, 17.3% were non-Hispanic Black, and 7.7% were Hispanic. The overall 30-day reintubation rate was 0.33%. After adjusting for age, body mass index,&nbsp;sex, and comorbidities, non-Hispanic Black patients had increased 30-day reintubation compared to non-Hispanic White patients (odds ratio [OR] = 2.14, 95% confidence interval [CI] 1.70-2.69, and P&nbsp;&lt; 0.0001). There was no difference in 30-day reintubation for Hispanic patients compared to non-Hispanic White patients (OR = 1.08, 95% CI 0.67-1.65, and P&nbsp;= 0.747). Conclusions This analysis showed that non-Hispanic Black patients disproportionately had higher odds of 30-day reintubation following head and neck surgery. Hispanic ethnicity was not associated with increased odds of 30-day reintubation. More studies are needed to investigate the reasons for these racial differences

Force distribution on multiple bonds controls the kinetics of adhesion in stretched cells.

International audienceWe show herein how mechanical forces at macro or micro scales may affect the biological response at the nanoscale. The reason resides in the intimate link between chemistry and mechanics at the molecular level. These interactions occur under dynamic conditions such as the shear stress induced by flowing blood or the intracellular tension. Thus, resisting removal by mechanical forces, e.g., shear stresses, is a general property of cells provided by cellular adhesion. Using classical models issued from theoretical physics, we review the force regulation phenomena of the single bond. However, to understand the force regulation of cellular adhesion sites, we need to consider the collective behavior of receptor-ligand bonds. We discuss the applicability of single bond theories to describe collective bond behavior. Depending on bond configuration, e.g., presently "parallel" and "zipper", the number of bonds and dissociation forces variably affect the kinetics of multiple bonds. We reveal a marked efficiency of the collective organization to stabilize multiple bonds by sharply increasing bond lifetime compared to single bond. These theoretical predictions are then compared to experimental results of the literature concerning the kinetic parameters of bonds measured by atomic force microscopy and by shear flow. These comparisons reveal that the force-control of bonds strongly depends on whether the force distribution on multiple bonds is homogeneous, e.g., in AFM experiments, or heterogeneous, e.g., in shear flow experiments. This reinforces the need of calculating the stress/strain fields exerted on living tissues or cells at various scales and certainly down to the molecular scale