Search

Purpose The purpose of this study was to characterize the central epithelial thickness (CET) of penetrating keratoplasty corneal specimens obtained from patients with keratoconus (KC) and correlate the histological patterns with their clinical history. Methods Ex vivo histological imaging was performed to measure CET and total corneal thickness (TCT) in 56 patients with KC. Microscopic slides from penetrating keratoplasty corneal specimens, stained with hematoxylin and eosin were evaluated using bright field microscopy. CET and TCT were measured, and morphological features were studied. Clinical history regarding duration of KC prior to surgery and length of and tolerance to contact lens wear were compared and analyzed. Results The microscopic slides of all patients available for follow up (n = 48) were analyzed and CET and TCT were measured. The histological evaluation revealed 3 distinctive epithelial patterns. Pattern 1 with central hypertrophic and hydropic changes (n = 19) measured 70.89 ± 25.88 μm in CET and 308.63 ± 100.74 μm in TCT; Pattern 2 (n = 14) had not changed, similar to normal epithelium CET and TCT measuring 36.5 ± 7.02 μm and 260.14 ± 87.93 μm respectively. Pattern 3 (n = 15) demonstrated thinner central epithelium characterized by atrophy and focal hydropic changes measuring 19.93 ± 4.60 μm and 268.00 ± 79.39 μm in CET and TCT respectively (all p

From stents and large-diameter vascular grafts, to mechanical heart valves and blood pumps, blood-contacting devices are enjoying significant clinical success owing to the application of systemic antiplatelet and anticoagulation therapies. On the contrary, research into material and device hemocompatibility aimed at alleviating the need for systemic therapies has suffered a decline. This research area is undergoing a renaissance fueled by recent fundamental insights into coagulation and inflammation that are offering new avenues of investigation, the growing recognition of the limitations facing existing therapeutic approaches, and the severity of the cardiovascular disorders epidemic. This Opinion article discusses clinical needs for hemocompatible materials and the emerging research directions for fulfilling those needs. Based on the 2017 BloodSurf conference that brought together clinicians, scientists, and engineers from academia, industry, and regulatory bodies, its purpose is to draw the attention of the wider clinical and scientific community to stimulate further growth. STATEMENT OF SIGNIFICANCE: The article highlights recent fundamental insights into coagulation, inflammation, and blood-biomaterial interactions that are fueling a renaissance in the field of material hemocompatibility. It will be useful for clinicians, scientists, engineers, representatives of industry and regulatory bodies working on the problem of developing hemocompatible materials and devices for treating cardiovascular disorders.

Engineering design is a critical skill that all engineering students are expected to learn and is often the focus of final year capstone projects and first-year cornerstone projects. In the Systems Design Engineering Department at the University of Waterloo, engineering design is introduced to the students during an intense two-day Design Days Boot Camp. Design Days was originally conceived of and run in Fall 2016. The Fall 2018 version, Design Days 2.0, included substantial improvements focused on adding two additional design activities and a writing activity, strengthening the connection with first year content, and providing a greater variety of team experiences. The methods of achieving the nine intended learning outcomes of Design Days 2.0 are discussed and connected to CEAB graduate attributes. This demonstrates that meaningful learning can be achieved during a two-day boot camp that will starts students on the path towards professional engineering. Other departments are encouraged to use the presented intended learning outcomes, graduate attributes connections, and Design Days 2.0 descriptions as a template for their own design boot camp. Finally, Design Days 2.0 inspired ideas for further improvements including the incorporation of a software-focused design activity, adding budgetary constraints, and providing an opportunity for student reflection.

Purpose: Eyelid closure results in influx of neutrophils onto the ocular surface, which are non-responsive to inflammatory stimuli. This investigation examined whether incubation of blood-isolated neutrophils in closed-eye conditions induce a tear-film neutrophil phenotype.Methods: Blood-isolated neutrophils were incubated combining various conditions: hypoxia, corneal epithelial cells (HCEC), artificial tear solution (ATS).Results: A hypoxic environment induced no differential effect on membrane receptor expression. Incubation in the presence of HCEC resulted in membrane receptor upregulation and increase in caspase activation.Conclusions: Hypoxia, corneal epithelial cell exposure, or artificial tear fluid are insufficient to replicate a tear-film neutrophil phenotype using blood-isolated neutrophils.

The development of medical-device technology is constrained by the financial and ethical considerations of animal testing and clinical trials. Organ-on-a-chip systems are being developed to speed up drug development, yet there has been little recognition or support for the use of this technology in the development and testing of medical devices. In this Perspective, we introduce the concept of medical-device-on-a-chip (MDoC), highlight possible applications and discuss the potential of microfluidic high-throughput technologies for achieving significant time and cost savings over conventional testing. Rather than testing an entire macroscale device, a MDoC has the ability to recapitulate biological function in a physiome associated with medical-device use and to test interactions with device components. In the clinic, MDoCs could also incorporate individual human samples for personalized diagnostics. We also review research towards the integration of key elements of organ-on-a-chip technologies with medical-device testing. This Perspective puts forward the concept of medical-device-on-a-chip, that is, a microphysiological system that leverages organ-on-a-chip technology for the development and testing of medical devices.

There is a widely recognized need to improve the performance of vascular implants and external medical devices that come into contact with blood by reducing adverse reactions they cause, such as thrombosis and inflammation. These reactions lead to major adverse cardiovascular events such as heart attacks and strokes. Currently, they are managed therapeutically. This need remains unmet by the biomaterials research community. Recognized stagnation of the blood-biomaterial interface research translates into waning interest from clinicians, funding agencies, and practitioners of adjacent fields. The purpose of this contribution is to stir things up. It follows the 2014 BloodSurf meeting (74th International IUVSTA Workshop on Blood-Biomaterial Interactions), offers reflections on the situation in the field, and a three-pronged strategy integrating different perspectives on the biological mechanisms underlying blood-biomaterial interactions. The success of this strategy depends on reengaging clinicians and on the renewed cooperation of the funding agencies to support long-term efforts.

Fluorescence microscopy is widely used for the study of biological specimens. Deconvolution can significantly improve the resolution and contrast of images produced using fluorescence microscopy; in particular, Bayesian-based methods have become very popular in deconvolution fluorescence microscopy. An ongoing challenge with Bayesian-based methods is in dealing with the presence of noise in low SNR imaging conditions. In this study, we present a Bayesian-based method for performing deconvolution using dynamically updated nonstationary expectation estimates that can improve the fluorescence microscopy image quality in the presence of noise, without explicit use of spatial regularization.

A novel automated cell counting technique for cell sample images used to study the side-effects of lens cleaning solutions on human corneal epithelial cells is developed. The proposed multi-step approach integrates non-maximum suppression, seeded region growing, connected component analysis, and adaptive thresholding to produce segmentation and classification results that are robust to background illumination variation and clustering of cells. The proposed algorithm is computationally efficient, and experimental results show that the average detection rate of nucleated cells is greater than 90% with the proposed technique as opposed to the state-of-the-art level set method which gives an accuracy of less than 65%.

A lensfree spectral light-field fusion microscopy (LSLFM) system is presented for enabling contrast- and resolution-enhanced imaging of biological specimens. LSLFM consists of a pulsed multispectral lensfree microscope for capturing interferometric light-field encodings at various wavelengths, and Bayesian-based fusion to reconstruct a fused object light-field from the encodings. By fusing unique object detail information captured at different wavelengths, LSLFM can achieve improved resolution, contrast, and signal-to-noise ratio (SNR) over a single-channel lensfree microscopy system. A five-channel LSLFM system was developed and quantitatively evaluated to validate the design. Experimental results demonstrated that the LSLFM system provided SNR improvements of 6-12 dB, as well as a six-fold improvement in the dispersion index (DI), over that achieved using a single-channel, resolution-enhancing lensfree deconvolution microscopy system or its multi-wavelength counterpart. Furthermore, the LSLFM system achieved an increase in numerical aperture (NA) of ~16% over a single-channel resolution-enhancing lensfree deconvolution microscopy system at the highest-resolution wavelength used in the study. Samples of Staurastrum paradoxum, a waterborne algae, and human corneal epithelial cells were imaged using the system to illustrate its potential for enhanced imaging of biological specimens., Comment: 5 pages