The Transformative Impact of Extracellular Vesicles on Developing Sperm

Objective: To review the role of extracellular vesicles (EVs) released from the male reproductive tract and their impact on developing sperm. We discuss how sperm exiting the seminiferous tubules, although developmentally mature, require further modification. Acquisition of various functions including increased motility, transfer of cargoes and ability to undertake the acrosome reaction is mediated through the interaction between sperm and EVs. Methods: A review of the literature identified that EVs are released from different portions of the male reproductive tract, notably the epididymis and prostate. These EVs interact with sperm as they pass from the seminiferous tubules to the epididymis and vas deferens prior to ejaculation. Results: EVs are small lipid-bound particles carrying bespoke RNA, protein and lipid cargoes. These cargoes are loaded based on the state of the parent cell and are used to communicate with recipient cells. In sperm, these cargoes are essential for post-testicular modification. Conclusions: Interactions between developing sperm and EVs are important for the subsequent function of sperm. Prior to ejaculation, these interactions confer important changes for the post-testicular modification and development of sperm. Little is known about the interaction between EVs from the testes and the spermatogonial stem cell niche or developing sperm within the seminiferous tubules. However, the numerous roles of EVs in the post-testicular modification of sperm have led many to suspect that they may also play important roles in developing sperm within the testes

Development of retinal blood vessel segmentation methodology using wavelet transforms for assessment of diabetic retinopathy

Automated image processing has the potential to assist in the early detection of diabetes, by detecting changes in blood vessel diameter and patterns in the retina. This paper describes the development of segmentation methodology in the processing of retinal blood vessel images obtained using non-mydriatic colour photography. The methods used include wavelet analysis, supervised classifier probabilities and adaptive threshold procedures, as well as morphology-based techniques. We show highly accurate identification of blood vessels for the purpose of studying changes in the vessel network that can be utilized for detecting blood vessel diameter changes associated with the pathophysiology of diabetes. In conjunction with suitable feature extraction and automated classification methods, our segmentation method could form the basis of a quick and accurate test for diabetic retinopathy, which would have huge benefits in terms of improved access to screening people for risk or presence of diabetes

Sex Differences in rt-PA Utilization at Hospitals Treating Stroke: The National Inpatient Sample.

BACKGROUND AND PURPOSE: Sex and race disparities in recombinant tissue plasminogen activator (rt-PA) use have been reported. We sought to explore sex and race differences in the utilization of rt-PA at primary stroke centers (PSCs) compared to non-PSCs across the US. METHODS: Data from the National (Nationwide) Inpatient Sample (NIS) 2004-2010 was utilized to assess sex differences in treatment for ischemic stroke in PSCs compared to non-PSCs. RESULTS: There were 304,152 hospitalizations with a primary diagnosis of ischemic stroke between 2004 and 2010 in the analysis: 75,160 (24.7%) patients were evaluated at a PSC. A little over half of the patients evaluated at PSCs were female (53.8%). A lower proportion of women than men received rt-PA at both PSCs (6.8 vs. 7.5%, p \u3c 0.001) and non-PSCs (2.3 vs. 2.8%, p \u3c 0.001). After adjustment for potential confounders the odds of being treated with rt-PA remained lower for women regardless of presentation to a PSC (OR 0.87, 95% CI 0.81-0.94) or non-PSC (OR 0.88, 95% CI 0.82-0.94). After stratifying by sex and race, the lowest absolute treatment rates were observed in black women (4.4% at PSC, 1.9% at non-PSC). The odds of treatment, relative to white men, was however lowest for white women (PSC OR = 0.85, 95% CI 0.78-0.93; non-PSC OR = 0.80, 95% CI 0.75-0.85). In the multivariable model, sex did not modify the effect of PSC certification on rt-PA utilization (p-value for interaction = 0.58). CONCLUSION: Women are less likely to receive rt-PA than men at both PSCs and non-PSCs. Absolute treatment rates are lowest in black women, although the relative difference in men and women was greatest for white women

Learning Sparsity-Promoting Regularizers using Bilevel Optimization

We present a method for supervised learning of sparsity-promoting regularizers for denoising signals and images. Sparsity-promoting regularization is a key ingredient in solving modern signal reconstruction problems; however, the operators underlying these regularizers are usually either designed by hand or learned from data in an unsupervised way. The recent success of supervised learning (mainly convolutional neural networks) in solving image reconstruction problems suggests that it could be a fruitful approach to designing regularizers. Towards this end, we propose to denoise signals using a variational formulation with a parametric, sparsity-promoting regularizer, where the parameters of the regularizer are learned to minimize the mean squared error of reconstructions on a training set of ground truth image and measurement pairs. Training involves solving a challenging bilievel optimization problem; we derive an expression for the gradient of the training loss using the closed-form solution of the denoising problem and provide an accompanying gradient descent algorithm to minimize it. Our experiments with structured 1D signals and natural images show that the proposed method can learn an operator that outperforms well-known regularizers (total variation, DCT-sparsity, and unsupervised dictionary learning) and collaborative filtering for denoising. While the approach we present is specific to denoising, we believe that it could be adapted to the larger class of inverse problems with linear measurement models, giving it applicability in a wide range of signal reconstruction settings

Extracellular vesicles in urological malignancies

Extracellular vesicles (EVs) are small lipid bound structures released from cells containing bioactive cargoes. Both the type of cargo and amount loaded varies compared to that of the parent cell. The characterisation of EVs in cancers of the male urogenital tract has identified several cargoes with promising diagnostic and disease monitoring potential. EVs released by cancers of the male urogenital tract promote cell-to-cell communication, migration, cancer progression and manipulate the immune system promoting metastasis by evading the immune response. Their use as diagnostic biomarkers represents a new area of screening and disease detection, potentially reducing the need for invasive biopsies. Many validated EV cargoes have been found to have superior sensitivity and specificity than current diagnostic tools currently in use. The use of EVs to improve disease monitoring and develop novel therapeutics will enable clinicians to individualise patient management in the exciting era of personalised medicine

Impact of taxane-based chemotherapeutics on male reproductive function

Men and boys with cancer treated with chemotherapy are known to have reduced fertility following their treatment. This is because some chemotherapy drugs can damage the cells in the testicles that make sperm. This study found there is limited information available on the effect of one group of chemotherapy drugs, called taxanes, on testicular function and fertility. More studies are needed to aid clinicians in advising patients on how this taxane-based chemotherapy may affect their future fertility

Signal Processing on Product Spaces

We establish a framework for signal processing on product spaces of simplicial and cellular complexes. For simplicity, we focus on the product of two complexes representing time and space, although our results generalize naturally to products of simplicial complexes of arbitrary dimension. Our framework leverages the structure of the eigenmodes of the Hodge Laplacian of the product space to jointly filter along time and space. To this end, we provide a decomposition theorem of the Hodge Laplacian of the product space, which highlights how the product structure induces a decomposition of each eigenmode into a spatial and temporal component. Finally, we apply our method to real world data, specifically for interpolating trajectories of buoys in the ocean from a limited set of observed trajectories

Exergy Efficiency of Interplanetary Transfer Vehicles

In order to optimize systems, systems engineers require some sort of measure with which to compare vastly different system components. One such measure is system exergy, or the usable system work. Exergy balance analysis models provide a comparison of different system configurations, allowing systems engineers to compare different systems configuration options. This paper presents the exergy efficiency of several Mars transportation system configurations, using data on the interplanetary trajectory, engine performance, and vehicle mass. The importance of the starting and final parking orbits is addressed in the analysis, as well as intermediate hyperbolic escape and entry orbits within Earth and Mars' spheres of influence (SOIs). Propulsion systems analyzed include low-enriched uranium (LEU) nuclear thermal propulsion (NTP), high-enriched uranium (HEU) NTP, LEU methane (CH4) NTP, and liquid oxygen (LOX)/liquid hydrogen (LH2) chemical propulsion