Performance of deep learning restoration methods for the extraction of particle dynamics in noisy microscopy image sequences

Particle tracking in living systems requires low light exposure and short exposure times to avoid phototoxicity and photobleaching and to fully capture particle motion with high-speed imaging. Low-excitation light comes at the expense of tracking accuracy. Image restoration methods based on deep learning dramatically improve the signal-to-noise ratio in low-exposure data sets, qualitatively improving the images. However, it is not clear whether images generated by these methods yield accurate quantitative measurements such as diffusion parameters in (single) particle tracking experiments. Here, we evaluate the performance of two popular deep learning denoising software packages for particle tracking, using synthetic data sets and movies of diffusing chromatin as biological examples. With synthetic data, both supervised and unsupervised deep learning restored particle motions with high accuracy in two-dimensional data sets, whereas artifacts were introduced by the denoisers in three-dimensional data sets. Experimentally, we found that, while both supervised and unsupervised approaches improved tracking results compared with the original noisy images, supervised learning generally outperformed the unsupervised approach. We find that nicer-looking image sequences are not synonymous with more precise tracking results and highlight that deep learning algorithms can produce deceiving artifacts with extremely noisy images. Finally, we address the challenge of selecting parameters to train convolutional neural networks by implementing a frugal Bayesian optimizer that rapidly explores multidimensional parameter spaces, identifying networks yielding optimal particle tracking accuracy. Our study provides quantitative outcome measures of image restoration using deep learning. We anticipate broad application of this approach to critically evaluate artificial intelligence solutions for quantitative microscopy

Aortic stiffness as a marker of cardiac function and myocardial strain in patients undergoing aortic valve replacement

Background: Cardiac function and myocardial strain are affected by cardiac afterload, which is in part due to the stiffness of the aortic wall. In this study, we hypothesize that aortic pulse wave velocity (PWV) as a marker of aortic stiffness correlates with conventional clinical and biochemical markers of cardiac function and perioperative myocardial strain in aortic valve replacement (AVR). Methods: Patients undergoing AVR for aortic stenosis between June 2010 and August 2012 were recruited for inclusion in this study. PWV, NYHA class and left ventricular (LV) function were assessed pre-operatively. PWV was analysed both as a continuous and dichotomous variable according to age-standardized reference values. B-type natriuretic peptide (BNP) was measured pre-operatively, and at 3 h and 18-24 h after cardiopulmonary bypass (CPB). NYHA class, leg edema, and LV function were recorded at follow-up (409 ± 159 days). Results: Fifty-six patients (16 females) with a mean age of 71 ± 8.4 years were included, with 50 (89%) patients completing follow-up. The NYHA class of PWV-norm patients was significantly lower than PWV-high patients both pre- and post-operatively. Multiple logistic regression also highlighted PWV-cut off as an independent predictor of NYHA class pre- and post-operatively (OR 8.3, 95%CI [2.27,33.33] and OR 14.44, 95%CI [1.49,139.31] respectively). No significant relationship was observed between PWV and either LV function or plasma BNP. Conclusion: In patients undergoing AVR for aortic stenosis, PWV is independently related to pre- and post-operative NYHA class but not to LV function or BNP. These findings provisionally support the use of perioperative PWV as a non-invasive marker of clinical functional status, which when used in conjunction with biomarkers of myocardial strain such as BNP, may provide a holistic functional assessment of patients undergoing aortic valve surgery. However, in order for PWV assessment to be translated into clinical practice and utilised as more than simply a research tool, further validation is required in the form of larger prospective studies specifically designed to assess the relationship between PWV and these functional clinical outcomes

Potential biological role of poly (ADP-ribose) polymerase (PARP) in male gametes

Maintaining the integrity of sperm DNA is vital to reproduction and male fertility. Sperm contain a number of molecules and pathways for the repair of base excision, base mismatches and DNA strand breaks. The presence of Poly (ADP-ribose) polymerase (PARP), a DNA repair enzyme, and its homologues has recently been shown in male germ cells, specifically during stage VII of spermatogenesis. High PARP expression has been reported in mature spermatozoa and in proven fertile men. Whenever there are strand breaks in sperm DNA due to oxidative stress, chromatin remodeling or cell death, PARP is activated. However, the cleavage of PARP by caspase-3 inactivates it and inhibits PARP's DNA-repairing abilities. Therefore, cleaved PARP (cPARP) may be considered a marker of apoptosis. The presence of higher levels of cPARP in sperm of infertile men adds a new proof for the correlation between apoptosis and male infertility. This review describes the possible biological significance of PARP in mammalian cells with the focus on male reproduction. The review elaborates on the role played by PARP during spermatogenesis, sperm maturation in ejaculated spermatozoa and the potential role of PARP as new marker of sperm damage. PARP could provide new strategies to preserve fertility in cancer patients subjected to genotoxic stresses and may be a key to better male reproductive health

Inoperable severe aortic valve stenosis in geriatric patients: treatment options and mortality rates.

Among geriatric patients suffering from severe but inoperable aortic valve stenosis because of high surgical risk and severe co-morbidities,[1] some benefit from trans-aortic valve implantation (TAVI) while others are deemed too frail for TAVI and received medical treatment (MT). This study conducted in frail geriatric patients aimed at describing the patient's characteristics and the mortality rate associated with the treatment option (MT vs. TAVI) as well as the patient's characteristics associated with one-year mortality. [...

Transcatheter left atrial appendage closure for stroke prevention in atrial fibrillation with Amplatzer cardiac plug: the Belgian Registry

AIMS: The aim of the present study was to evaluate the procedural feasibility, the safety and the 1-year outcome following left atrial appendage (LAA) closure using the Amplatzer cardiac plug (ACP) in Belgium. METHODS AND RESULTS: Data were prospectively collected among 90 consecutive patients, undergoing LAA closure with an ACP in 7 Belgian centres between June 2009 and September 2012. The patients (56 males, 74 +/- 8 years) were at high risk for stroke (CHA2DS2-VASc = 4.4 +/- 1.8) and bleeding (HAS-BLED = 3.3 +/- 1.3).Technical success was obtained in all but one patient and procedural success was 95%. Procedural major adverse events (MAE) were 3 tamponades resulting in death in one case. Minor complications were 3 insignificant pericardial effusions, 2 transient myocardial ischaemia due to air embolism and 1 femoral pseudoaneurysm. At 1-y follow-up, there were 4 deaths, 2 minor strokes, 1 tamponade and 1 myocardial infarction. Overall survival was 94% and freedom from MAE was 88%. In our population, the expected annual stroke risk according to the CHA2DS2-VASc score was 5.08%, while the observed stroke rate was 2.14%/year. CONCLUSIONS: The Belgian registry shows that LAA closure using the ACP device is feasible and safe. At 1-y follow-up, the observed stroke rate was 2.14%/year, less than predicted by the CHA2DS2-VASc score. Longer follow-up is needed to evaluate the long-term safety and its efficacy in reducing stroke.status: publishe

Transcatheter left atrial appendage closure for stroke prevention in atrial fibrillation with Amplatzer cardiac plug: the Belgian Registry

AIMS: The aim of the present study was to evaluate the procedural feasibility, the safety and the 1-year outcome following left atrial appendage (LAA) closure using the Amplatzer cardiac plug (ACP) in Belgium. METHODS AND RESULTS: Data were prospectively collected among 90 consecutive patients, undergoing LAA closure with an ACP in 7 Belgian centres between June 2009 and September 2012. The patients (56 males, 74 +/- 8 years) were at high risk for stroke (CHA2DS2-VASc = 4.4 +/- 1.8) and bleeding (HAS-BLED = 3.3 +/- 1.3).Technical success was obtained in all but one patient and procedural success was 95%. Procedural major adverse events (MAE) were 3 tamponades resulting in death in one case. Minor complications were 3 insignificant pericardial effusions, 2 transient myocardial ischaemia due to air embolism and 1 femoral pseudoaneurysm. At 1-y follow-up, there were 4 deaths, 2 minor strokes, 1 tamponade and 1 myocardial infarction. Overall survival was 94% and freedom from MAE was 88%. In our population, the expected annual stroke risk according to the CHA2DS2-VASc score was 5.08%, while the observed stroke rate was 2.14%/year. CONCLUSIONS: The Belgian registry shows that LAA closure using the ACP device is feasible and safe. At 1-y follow-up, the observed stroke rate was 2.14%/year, less than predicted by the CHA2DS2-VASc score. Longer follow-up is needed to evaluate the long-term safety and its efficacy in reducing stroke

Left atrial appendage occlusion with the Amplatzer Cardiac Plug could improve survival and prevent thrombo-embolic and major bleeding events in atrial fibrillation patients with increased bleeding risk

AIMS: Literature suggests a beneficial effect of percutaneous left atrial appendage occlusion (LAAO) to prevent thrombo-embolic events in patients with non-rheumatic atrial fibrillation (AF). We compared outcome of LAAO versus ‘suboptimal standard’ treatment in AF patients with high bleeding risk. METHODS AND RESULTS: Patients with sufficient follow-up data (n = 125) who underwent LAAO with the Amplatzer Cardiac Plug (ACP) were selected from the Belgian ACP database. AF patients who survived intracranial haemorrhage were recruited from the Leuven Neurosurgical Registry (LNR, n = 113). After propensity score adjustment, the outcome of both groups was compared for the combined end point (death, stroke, transient ischaemic attack, systemic emboli, and major bleeding event). The LAAO group did not differ from the LNR group for mean age and gender (74 ± 7 versus 75 ± 10 years, P = 0.29; female 39% versus 48%, P = 0.18). However, the CHA2DS2-VASc and HAS-BLED scores were both higher in the LAAO group (4.8 ± 1.7 versus 3.9 ± 1.7, P = 0.0001; 3.5 ± 1.4 versus 3.2 ± 1.4, P = 0.036). After propensity score adjustment, the risk for the primary end point was significantly higher for the LNR group (HR 2.012, 95% CI 1.113-3.638). CONCLUSION: LAAO with ACP seems to improve the combination of survival and the prevention of thrombo-embolic and major bleeding events in patients with atrial fibrillation and increased bleeding risk.status: publishe

Left atrial appendage occlusion with the Amplatzer Cardiac Plug could improve survival and prevent thrombo-embolic and major bleeding events in atrial fibrillation patients with increased bleeding risk.

Aims Literature suggests a beneficial effect of percutaneous left atrial appendage occlusion (LAAO) to prevent thrombo-embolic events in patients with non-rheumatic atrial fibrillation (AF). We compared outcome of LAAO versus ‘suboptimal standard’ treatment in AF patients with high bleeding risk. Methods and results Patients with sufficient follow-up data (n = 125) who underwent LAAO with the Amplatzer Cardiac Plug (ACP) were selected from the Belgian ACP database. AF patients who survived intracranial haemorrhage were recruited from the Leuven Neurosurgical Registry (LNR, n = 113). After propensity score adjustment, the outcome of both groups was compared for the combined end point (death, stroke, transient ischaemic attack, systemic emboli, and major bleeding event). The LAAO group did not differ from the LNR group for mean age and gender (74 ± 7 versus 75 ± 10 years, P = 0.29; female 39% versus 48%, P = 0.18). However, the CHA2DS2-VASc and HAS-BLED scores were both higher in the LAAO group (4.8 ± 1.7 versus 3.9 ± 1.7, P = 0.0001; 3.5 ± 1.4 versus 3.2 ± 1.4, P = 0.036). After propensity score adjustment, the risk for the primary end point was significantly higher for the LNR group (HR 2.012, 95% CI 1.113-3.638). Conclusion LAAO with ACP seems to improve the combination of survival and the prevention of thrombo-embolic and major bleeding events in patients with atrial fibrillation and increased bleeding ris