Effects of non-vitamin K antagonist oral anticoagulants on fibrin clot and whole blood clot formation, integrity and thrombolysis in patients with atrial fibrillation

Non-vitamin K antagonist oral anticoagulants (NOACs) are replacing warfarin and heparins in several clinical situations. With varying modes of action, the effects of NOACs on thrombus formation, integrity, and lysis is unknown. To determine whether two techniques of thrombelastography (TEG) and a micro-plate assay (MPA) provide novel data on thrombus formation, integrity and lysis in those taking a NOACs compared to warfarin and a control group taking aspirin. We assessed thrombogenesis, clot integrity and fibrinolysis in blood (TEG) and plasma (MPA) from 182 atrial fibrillation patients—50 on aspirin, 50 on warfarin, and 82 on a NOAC (17 apixaban, 19 dabigatran and 46 rivaroxaban). Eleven of 16 TEG indices and 4 of 5 MPA indices differed (p ≤ 0.01) between those on aspirin, warfarin or a NOAC. Three TEG indices and 4 MPA indices differed (p < 0.01) between the NOACs. Time to initiation of clot formation was most rapid on apixaban, then rivaroxaban and slowest on dabigatran. The rate of clot formation was most rapid on dabigatran, then apixaban, and slowest on rivaroxaban. Clot density was greatest on rivaroxaban, then apixaban, but weakest on dabigatran. The rate of clot dissolution was most rapid in apixaban, then dabigatran, and slowest on rivaroxaban. The TEG and MPA identify major differences in thrombogenesis and fibrinolysis in different NOACs. These techniques may have value in investigating the effects of these drugs on haemostasis in a clinical setting, and in identifying those in need of targeted therapy

Pseudomonas aeruginosa isolates co-incubated with Acanthamoeba castellanii exhibit phenotypes similar to chronic cystic fibrosis isolates

The opportunistic pathogen, Pseudomonas aeruginosa , is ubiquitous in the environment, and in humans is capable of causing acute and chronic infections. P. aeruginosa , when co-incubated with the bacterivorous amoeba, Acanthamoeba castellanii , for extended periods, produced genetic and phenotypic variants. Sequencing of late-stage amoeba-adapted P. aeruginosa isolates demonstrated single nucleotide polymorphisms within genes that encode known virulence factors, and this correlated with a reduction in expression of virulence traits. Virulence towards the nematode, Caenorhabditis elegans , was attenuated in late-stage amoeba-adapted P. aeruginosa compared to early stage amoeba-adapted and non-adapted counterparts. Late-stage amoeba-adapted P. aeruginosa lost competitive fitness compared to non-adapted counterparts when grown in nutrient rich media. However, non-adapted P. aeruginosa were rapidly cleared by amoeba predation, whereas late-stage amoeba-adapted isolates remained in higher numbers 24 h after ingestion by amoeba. In addition, there was reduced uptake by macrophage of amoeba-adapted isolates and reduced uptake by human neutrophils as well as increased survival in the presence of neutrophils. Our findings indicate that the selection imposed by amoeba on P. aeruginosa resulted in reduced virulence over time. Importantly, the genetic and phenotypic traits possessed by late-stage amoeba-adapted P. aeruginosa are similar to what is observed for isolates obtained from chronic cystic fibrosis infections. This notable overlap in adaptation to different host types suggests similar selection pressures among host cell types. Author Summary Pseudomonas aeruginosa is an opportunistic pathogen that causes both acute infections in plants and animals, including humans and also causes chronic infections in immune compromised and cystic fibrosis patients. This bacterium is commonly found in soils and water where bacteria are constantly under threat of being consumed by the bacterial predators, protozoa. To escape being killed, bacteria have evolved a suite of mechanisms that protect them from being consumed or digested. Here we examined the effect of long-term predation on the genotype and phenotypes expressed by P. aeruginosa. We show that long-term co-incubation with protozoa resulted in mutations in the bacteria that made them less pathogenic. This is particularly interesting as we see similar mutations arise in bacteria associated with chronic infections. Thus, predation by protozoa and long term colonization of the human host may represent similar environments that select for similar losses in gene functions

Insulin receptor substrate adaptor proteins mediate prognostic gene expression profiles in breast cancer

Therapies targeting the type I insulin-like growth factor receptor (IGF-1R) have not been developed with predictive biomarkers to identify tumors with receptor activation. We have previously shown that the insulin receptor substrate (IRS) adaptor proteins are necessary for linking IGF1R to downstream signaling pathways and the malignant phenotype in breast cancer cells. The purpose of this study was to identify gene expression profiles downstream of IGF1R and its two adaptor proteins. IRS-null breast cancer cells (T47D-YA) were engineered to express IRS-1 or IRS-2 alone and their ability to mediate IGF ligand-induced proliferation, motility, and gene expression determined. Global gene expression signatures reflecting IRS adaptor specific and primary vs. secondary ligand response were derived (Early IRS-1, Late IRS-1, Early IRS-2 and Late IRS-2) and functional pathway analysis examined. IRS isoforms mediated distinct gene expression profiles, functional pathways, and breast cancer subtype association. For example, IRS-1/2-induced TGFb2 expression and blockade of TGFb2 abrogated IGF-induced cell migration. In addition, the prognostic value of IRS proteins was significant in the luminal B breast tumor subtype. Univariate and multivariate analyses confirmed that IRS adaptor signatures correlated with poor outcome as measured by recurrence-free and overall survival. Thus, IRS adaptor protein expression is required for IGF ligand responses in breast cancer cells. IRS-specific gene signatures represent accurate surrogates of IGF activity and could predict response to anti-IGF therapy in breast cancer

Simulation of gait asymmetry and energy transfer efficiency between unilateral and bilateral amputees

Efficient walking or running requires symmetrical gait. Gait symmetry is one of the key factors in efficient human dynamics, kinematics and kinetics. The desire of individuals with a lower-limb amputation to participate in sports has resulted in the development of energy-storing and-returning (ESR) feet. This paper analyses a case study to show the effect of symmetry and asymmetry as well as energy transfer efficiency during periodic jumping between simulated bilateral and unilateral runners. A custom gait analysis system is developed as part of this project to track the motion of the body of a physically active subject during a set of predefined motions. Stance and aerial times are accurately measured using a high speed camera. Gait frequency, the level of symmetry and the non-uniform displacement between left and right foot and their effects on the position of the Centre of Mass (CM) were used as criteria to calculate both peak energies and transformation efficiency. Gait asymmetry and discrepancy of energy transfer efficiency between the intact foot and the ESR are observed. It is concluded that unilateral runners require excessive effort to compensate for lack of symmetry as well as asymmetry in energy transfer, causing fatigue which could be a reason why bilateral amputee runners using ESR feet have a superior advantage over unilateral amputees

Metamaterial superlenses operating at visible wavelength for imaging applications

© 2018 The Authors. Published by Nature. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1038/s41598-018-33572-yIn this paper, a novel design for a metamaterial lens (superlens) based on a Photonic Crystal (PC) operating at visible wavelengths is reported. The proposed superlens consist of a gallium phosphide (GaP) dielectric slab waveguide with a hexagonal array of silver rods embedded within the GaP dielectric. In-house 2DFDTD numerical method is used to design and optimize the proposed superlens. Several superlenses are designed and integrated within a same dielectric platform, promoting the proof-of-concept (POC) of possible construction of an array of superlenses (or sub-lenses to create an M-Lens) for light field imaging applications. It is shown that the concavity of the superlens and positioning of each sub-lens within the array strongly affects the performances of the image in terms of resolution. Defects and various geometrical shapes are introduced to construct and optimize the proposed superlenses and increase the quality of the image resolution. It is shown that the orientation of the active region (ellipse) along x and y axis has tremendous influence on the quality of image resolution. In order to investigate the performance characteristics of the superlenses, transmitted power is calculated using 2D FDTD for image projections at various distances (in x and y plane). It is also shown, how the proposed superlens structures could be fabricated using standard micro fabrication techniques such as electron beam lithography, inductively coupled Reactive ion etching, and glancing angle evaporation methods. To the best of our knowledge, these are the first reported POC of superlenses, integrated in a monolithic platform suitable for high imaging resolution that can be used for light field imaging applications at visible wavelength. The proposed superlenses (integrated in a single platform M-Lens) will have tremendous impact on imaging applications

Identification of QTL genes for BMD variation using both linkage and gene-based association approaches

Low bone mineral density (BMD) is a risk factor for osteoporotic fracture with a high heritability. Previous large scale linkage study in Northern Chinese has identified four significant quantitative trait loci (QTL) for BMD variation on chromosome 2q24, 5q21, 7p21 and 13q21. We performed a replication study of these four QTL in 1,459 Southern Chinese from 306 pedigrees. Successful replication was observed on chromosome 5q21 for femoral neck BMD with a LOD score of 1.38 (nominal p value = 0.006). We have previously identified this locus in a genome scan meta-analysis of BMD variation in a white population. Subsequent QTL-wide gene-based association analysis in 800 subjects with extreme BMD identified CAST and ERAP1 as novel BMD candidate genes (empirical p value of 0.032 and 0.014, respectively). The associations were independently replicated in a Northern European population (empirical p value of 0.01 and 0.004 for CAST and ERAP1, respectively). These findings provide further evidence that 5q21 is a BMD QTL, and CAST and ERAP1 may be associated with femoral neck BMD variation

A uniform procedure for the purification of CDK7/CycH/MAT1, CDK8/CycC and CDK9/CycT1

We have established a uniform procedure for the expression and purification of the cyclin-dependent kinases CDK7/CycH/MAT1, CDK8/CycC and CDK9/CycT1. We attach a His(6)-tag to one of the subunits of each complex and then co-express it together with the other subunits in Spodoptera frugiperda insect cells. The CDK complexes are subsequently purified by Ni(2+)-NTA and Mono S chromatography. This approach generates large amounts of active recombinant kinases that are devoid of contaminating kinase activities. Importantly, the properties of these recombinant kinases are similar to their natural counterparts (Pinhero et al. 2004, Eur J Biochem 271:1004-14). Our protocol provides a novel systematic approach for the purification of these three (and possibly other) recombinant CDKs

Sex-based differences in risk of ischaemic stroke or systemic embolism after BNT162b2 or CoronaVac COVID-19 vaccination in patients with atrial fibrillation: a self-controlled case series and nested case-control study

AIMS: Patients with atrial fibrillation (AF) have a higher risk of ischemic stroke or systemic embolism with a greater risk for female patients. This study aims to evaluate the risk of ischemic stroke or systemic embolism and bleeding following COVID-19 vaccination in patients with AF and the sex differences. METHODS AND RESULTS: Self-controlled case series (SCCS) analysis was conducted to evaluate the risk of ischemic stroke or systemic embolism and bleeding following BNT162b2 or CoronaVac in patients with AF, using the territory-wide electronic medical records from the Hospital Authority and vaccination records from the Department of Health in Hong Kong. Patients with a primary diagnosis of ischemic stroke or systemic embolism or bleeding in the inpatient setting between February 23, 2021 and March 31, 2022 were included. A nested case-control analysis was also conducted with each case randomly matched with ten controls according to sex, age, Charlson comorbidity index and date of hospital admission. Conditional Poisson regression was used in the SCCS analysis and conditional logistic regression was used in nested case-control analysis to assess the risks and all analyses were stratified by sex and type of vaccines. Among 51 158 patients with AF, we identified an increased risk of ischemic stroke or systemic embolism after the first dose of BNT162b2 in SCCS analysis during 0-13 days (incidence rate ratio 6.60[95% CI 1.51-28.77]) and 14-27 days (6.53[95% CI 1.31-32.51]), and nested case-control analysis during 0-13 days (adjusted odds ratio 6.21 [95% CI 1.14-33.91]) and 14-27 days (5.52 [95% CI 1.12-27.26]) only in female patients. The increased risk in female patients following the first dose of CoronaVac was only detected during 0-13 days (3.88 [95% CI 1.67-9.03]) in the nested case-control analysis. No increased risk of ischemic stroke or systemic embolism was identified in male patients and no increased risk of bleeding was detected in all patients with AF for both vaccines. An increased risk of ischemic stroke or systemic embolism after COVID-19 was also observed in both females (17.42 [95% CI 5.08-59.73]) and males (6.63 [95% CI 2.02-21.79]). CONCLUSIONS: The risk of ischemic stroke or systemic embolism after COVID-19 vaccination was only increased in female patients with AF. However, as the risk after COVID-19 was even higher, proactive uptake of COVID-19 vaccines is recommended to prevent the potential severe outcomes after infection

Engineering supported membranes for cell biology

Cell membranes exhibit multiple layers of complexity, ranging from their specific molecular content to their emergent mechanical properties and dynamic spatial organization. Both compositional and geometrical organizations of membrane components are known to play important roles in life processes, including signal transduction. Supported membranes, comprised of a bilayer assembly of phospholipids on the solid substrate, have been productively served as model systems to study wide range problems in cell biology. Because lateral mobility of membrane components is readily preserved, supported lipid membranes with signaling molecules can be utilized to effectively trigger various intercellular reactions. The spatial organization and mechanical deformation of supported membranes can also be manipulated by patterning underlying substrates with modern micro- and nano-fabrication techniques. This article focuses on various applications and methods to spatially patterned biomembranes by means of curvature modulations and spatial reorganizations, and utilizing them to interface with live cells. The integration of biological components into synthetic devices provides a unique approach to investigate molecular mechanisms in cell biology

Comparison study of microarray meta-analysis methods

<p>Abstract</p> <p>Background</p> <p>Meta-analysis methods exist for combining multiple microarray datasets. However, there are a wide range of issues associated with microarray meta-analysis and a limited ability to compare the performance of different meta-analysis methods.</p> <p>Results</p> <p>We compare eight meta-analysis methods, five existing methods, two naive methods and a novel approach (mDEDS). Comparisons are performed using simulated data and two biological case studies with varying degrees of meta-analysis complexity. The performance of meta-analysis methods is assessed via ROC curves and prediction accuracy where applicable.</p> <p>Conclusions</p> <p>Existing meta-analysis methods vary in their ability to perform successful meta-analysis. This success is very dependent on the complexity of the data and type of analysis. Our proposed method, mDEDS, performs competitively as a meta-analysis tool even as complexity increases. Because of the varying abilities of compared meta-analysis methods, care should be taken when considering the meta-analysis method used for particular research.</p