2D speckle tracking: a diagnostic and prognostic tool of paramount importance.

OBJECTIVE: We aimed to conduct a review of the literature relevant to cardiac imaging techniques and summarize the use of different non-invasive imaging modalities in the assessment of ventricular size, function, and mechanics. The current review emphasizes the benefits of speckle tracking imaging (STI), highlighting its use in demonstrating myocardial strain. This robust technique is a recent addition to the existing imaging techniques that are used to assess the myocardium. In terms of effectively determining the left ventricle ejection fraction, it is a comparable technique to cardiac magnetic resonance. The use of STI method for image acquisition relies on semiautomatic identification of the border and deformation of the region of interest, and is also independent of the angle of insonation, thus it increases the inter-and intra-observer reproducibility in contrast to the conventional tissue doppler imaging. MATERIALS AND METHODS: The databases of PubMed, Scopus, and Embase were thoroughly searched for the following keywords: 2- dimensional/ two-dimensional/ 2-D, speckle/strain tracking, systolic dysfunction, and heart failure. The studies selected described image acquisition techniques and the application of this imaging modality in various clinical settings. The selected journal articles were perused to provide the best possible analysis of STI. RESULTS: Our comparative analysis demonstrated that the STI, when compared with the conventional echocardiography, is a more sensitive image acquiring technique for detecting subclinical myocardial dysfunction. Based on the analysis it can be stated that the STI can provide valuable information on both regional and global myocardial function, and it can also quantify cardiac synchronicity and rotation. Additionally, it serves as a better prognostic indicator. CONCLUSIONS: The change in longitudinal strain can serve as an early marker of the left ventricular systolic dysfunction, and therefore, monitoring via STI has both diagnostic and prognostic value in heart failure, ischemic heart disease, valvulopathies, chemotherapy-induced cardiotoxicity, and cardiac resynchronization therapy. Despite the lack of standardization, the method is also effective in assessing the right ventricle and left atrial function and arterial rigidity.

Atypical attentional filtering of visual information in youth with chromosome 22q11.2 deletion syndrome as indexed by event-related potentials.

BACKGROUND: Youth with chromosome 22q11.2 deletion syndrome (22q) face one of the highest genetic risk factors for the development of schizophrenia. Previous research suggests impairments in attentional control and potential interactions with elevated anxiety and reduced adaptive functioning may increase the risk for developing psychosis in this population. Here, we examined how variations in attentional control relate to the presence or severity of psychosis-proneness symptoms in these individuals. METHODS: To achieve this, we measured attentional control in youth (12-18 years) with 22q (N = 35) compared to a typically developing group (N = 45), using a flanker task (the Distractor Target task) while measuring neural activity with event-related potentials. RESULTS: Similar to previous findings observed in people with schizophrenia, greater attentional capture by, and reduced suppression of, non-target flanker stimuli characterized participants with 22q and was indexed by the N2pc (N2-posterior-contralateral) and PD (distractor positivity) components. Although we observed no relationships between these components and measures of psychosis-proneness in youth with 22q, these individuals endorsed a relatively low incidence of positive symptoms overall. CONCLUSIONS: Our results provide neural evidence of an attentional control impairment in youth with 22q that suggests these individuals experience sustained attentional focus on irrelevant information and reduced suppression of distracting stimuli in their environment. Impairments in attentional control might be a valid biomarker of the potential to develop attenuated positive symptoms or frank psychosis in high-risk individuals long before the age at which such symptoms typically arise. The evaluation of such a hypothesis, and the preventive potential for the putative biomarker, should be the focus of future studies.

Covalent immobilisation of VEGF on plasma-coated electrospun scaffolds for tissue engineering applications.

Recent findings in the field of biomaterials and tissue engineering provide evidence that surface immobilised growth factors display enhanced stability and induce prolonged function. Cell response can be regulated by material properties and at the site of interest. To this end, we developed scaffolds with covalently bound vascular endothelial growth factor (VEGF) and evaluated their mitogenic effect on endothelial cells in vitro. Nano- (254±133 nm) or micro-fibrous (4.0±0.4 µm) poly(ɛ-caprolactone) (PCL) non-wovens were produced by electrospinning and coated in a radio frequency (RF) plasma process to induce an oxygen functional hydrocarbon layer. Implemented carboxylic acid groups were converted into amine-reactive esters and covalently coupled to VEGF by forming stable amide bonds (standard EDC/NHS chemistry). Substrates were analysed by X-ray photoelectron spectroscopy (XPS), enzyme-linked immuno-assays (ELISA) and immunohistochemistry (anti-VEGF antibody and VEGF-R2 binding). Depending on the reaction conditions, immobilised VEGF was present at 127±47 ng to 941±199 ng per substrate (6mm diameter; concentrations of 4.5 ng mm(-2) or 33.3 ng mm(-2), respectively). Immunohistochemistry provided evidence for biological integrity of immobilised VEGF. Endothelial cell number of primary endothelial cells or immortalised endothelial cells were significantly enhanced on VEGF-functionalised scaffolds compared to native PCL scaffolds. This indicates a sustained activity of immobilised VEGF over a culture period of nine days. We present a versatile method for the fabrication of growth factor-loaded scaffolds at specific concentrations.

The interaction of cells and bacteria with surfaces structured at the nanometre scale.

The current development of nanobiotechnologies requires a better understanding of cell-surface interactions on the nanometre scale. Recently, advances in nanoscale patterning and detection have allowed the fabrication of appropriate substrates and the study of cell-substrate interactions. In this review we discuss the methods currently available for nanoscale patterning and their merits, as well as techniques for controlling the surface chemistry of materials at the nanoscale without changing the nanotopography and the possibility of truly characterizing the surface chemistry at the nanoscale. We then discuss the current knowledge of how a cell can interact with a substrate at the nanoscale and the effect of size, morphology, organization and separation of nanofeatures on cell response. Moreover, cell-substrate interactions are mediated by the presence of proteins adsorbed from biological fluids on the substrate. Many questions remain on the effect of nanotopography on protein adsorption. We review papers related to this point. As all these parameters have an influence on cell response, it is important to develop specific studies to point out their relative influence, as well as the biological mechanisms underlying cell responses to nanotopography. This will be the basis for future research in this field. An important topic in tissue engineering is the effect of nanoscale topography on bacteria, since cells have to compete with bacteria in many environments. The limited current knowledge of this topic is also discussed in the light of using topography to encourage cell adhesion while limiting bacterial adhesion. We also discuss current and prospective applications of cell-surface interactions on the nanoscale. Finally, based on questions raised previously that remain to be solved in the field, we propose future directions of research in materials science to help elucidate the relative influence of the physical and chemical aspects of nanotopography on bacteria and cell response with the aim of contributing to the development of nanobiotechnologies.