Publications

We presenta robust, long-range optical autofocus system for microscopy utilizing machine learning. This can be useful for experiments with long image data acquisition times that may be impacted by defocusing resulting from drift of components, for example due to changes in temperature or mechanical drift. It is also useful for automated slide scanning or multiwell plate imaging where the sample(s) to be imaged may not be in the same horizontal plane throughout the image data acquisition. To address the impact of (thermal or mechanical) fluctuations over time in the optical autofocus system itself, we utilize a convolutional neural network (CNN) that is trained over multiple days to account for such fluctuations. To address the trade-off between axial precision and range of the autofocus, we implement orthogonal optical readouts with separate CNN training data, thereby achieving an accuracy well within the 600 nm depth of field of our 1.3 numerical aperture objective lens over a defocus range of up to approximately +/-100 μm. We characterize the performance of this autofocus system and demonstrate its application to automated multiwell plate single molecule localization microscopy.

Intravascular ultrasound (IVUS) elastography is a new imaging technique that reveals local mechanical properties of the vascular wall by measuring the local strain. Last year, low resolution elastograms (64 angles) were presented. In this study, we present high resolution elastograms. Patients (n=8) referred for Percutaneous Transluminal Coronary Angioplasty were investigated with an EndoSonics InVision echoapparatus. The beam-formed image mode (512 angles) ultrasound data (Fc=20 MHz) was acquired with an acquisition system that was assembled in collaboration with EndoSonics. Elastograms were determined using data acquired near end-diastole. In this phase of the pressure cycle, catheter motion was minimal. Frames with a pressure difference of approx. 5 mmHg were taken to determine the elastograms. Elastograms of soft, calcified and stented plaques were determined. The elastogram of a soft plaque, as identified from the deformation during the pressure cycle, reveals strain values up to 2% with increased strain regions at the shoulders of the plaque. Calcified material, as identified from the echogram, shows strain values of 0-0.2%. The elastogram of stented plaques reveals very low strain values, except for two regions: these are between the stent struts and at the shoulders of the plaque.

Diabetes mellitus is a well-known risk factor for future adverse cardiac events after coronary intervention with conventional metal stents. In this study, the impact of sirolimus-eluting stents (SES) were evaluated in a consecutive group of diabetic patients undergoing elective percutaneous coronary treatment and compared to a population treated with bare metal stents.From April 2002, a policy of routine SES implantation has been instituted in our hospital. During 1 year of enrollment, a total of 112 consecutive diabetic patients with de novo coronary lesions were electively treated with SES (SES group). A similar group for comparison comprised 118 consecutive patients treated with bare metal stents in the preceding period (the pre-SES group). After 1-year follow-up, the cumulative rate of major adverse cardiac events (death, myocardial infarction, and any repeat revascularization) was 17.3% in the SES group versus 30.2% in the pre-SES group (hazard ratio, 0.54 [95% confidence interval, 0.32-0.91]; p = 0.02), mainly due to a marked reduction in the need for repeat revascularization (10.2% versus 23.5%; hazard ratio, 0.40 [95% confidence interval, 0.21-0.78]; p = 0.007).Routine utilization of SES for diabetic patients significantly reduces the rate of adverse cardiac events at 1 year compared to bare metal stents.

No abstract is provided for this article.

It remains unknown whether the treatment of hypertension influences the mortality of patients diagnosed with coronavirus disease 2019 (COVID-19).

Lower airway bacterial colonisation (LABC) is associated with increased exacerbation frequency in COPD patients. We hypothesised that time to next exacerbation would be dependent on their stable LABC status, individual colonising species and total bacterial load. Sputum samples collected from stable COPD patients were analysed by qPCR to detect <i>H. influenzae, M. catarrhalis</i> and <i>S. pneumoniae</i>. Patients were sub-grouped by LABC status, colonising species and by high or low total bacterial load, using a cut-off of 10⁷ cfu/ml (Singh et al., 2014). Patients prospectively completed daily symptom diary cards to determine time to next exacerbation over a 180-day period using validated symptomatic criteria (Seemungal et al., 1998). 148 COPD patients were included, of whom LABC was detected in 62 (42%). 82 (55%) patients experienced an exacerbation within 180 days. Median time to next exacerbation was significantly shorter in patients with high total bacterial load (n=33) compared with those with low total bacterial load (n=29) (52 [29-74] vs. 85 [62-113] days, p=0.016, Figure 1). There was no significant difference in time to next exacerbation between non-LABC and LABC patients (p=0.737) or by colonising species (p=0.187). Stable COPD patients with high airway total bacterial load have a shorter time to next exacerbation and should be targeted in future interventional studies to prevent exacerbations.

Background The use of stents improves the result after balloon coronary angioplasty. Thrombogenicity of stents is, however, a concern. In the present study, we compared stents with an antithrombotic coating with regular stents. Methods and Results Regular stents were placed in coronary arteries of pigs receiving no aspirin (group 1; n=8) or aspirin over 4 weeks (group 2, n=10) or 12 weeks (group 3, n=9). Stents coated with heparin (antithrombin III uptake, 5 pmol/stent) were placed in 7 pigs that did not receive aspirin (group 4). The other animals received aspirin and coated stents with a heparin activity of 12 pmol antithrombin III/stent (group 5, n=10) or 20 pmol/stent (group 6, n=10; group 7, n=10). Quantitative arteriography was performed at implantation and after 4 (groups 1, 2, and 4 through 6) or 12 weeks (groups 3 and 7). In an additional 5 animals, five regular and five coated stents (20 pmol/stent) were placed and explanted after 5 days for examination of the early responses to the implants. Thrombotic occlusion of the regular stent occurred in 9 of 27 in groups 1 through 3. However, in 0 of 30 of the animals receiving high-activity heparin-coated stents (groups 5 through 7), thrombotic stent occlusion was observed ( P &lt;.001). Histological analysis at 4 weeks showed that the neointima in group 6 was thicker compared with its control group 2 (259±104 and 117±36 μm, P &lt;.01), but at 12 weeks the thickness was similar (152±61 and 198±49 μm, respectively). Comparison at 5 days suggested delayed endothelialization of the coating. Conclusions High-activity heparin coating of stents eliminates subacute thrombosis in porcine coronary arteries.