Resolution of tonic concentrations of highly similar neurotransmitters using voltammetry and deep learning.

With advances in our understanding regarding the neurochemical underpinnings of neurological and psychiatric diseases, there is an increased demand for advanced computational methods for neurochemical analysis. Despite having a variety of techniques for measuring tonic extracellular concentrations of neurotransmitters, including voltammetry, enzyme-based sensors, amperometry, and in vivo microdialysis, there is currently no means to resolve concentrations of structurally similar neurotransmitters from mixtures in the in vivo environment with high spatiotemporal resolution and limited tissue damage. Since a variety of research and clinical investigations involve brain regions containing electrochemically similar monoamines, such as dopamine and norepinephrine, developing a model to resolve the respective contributions of these neurotransmitters is of vital importance. Here we have developed a deep learning network, DiscrimNet, a convolutional autoencoder capable of accurately predicting individual tonic concentrations of dopamine, norepinephrine, and serotonin from both in vitro mixtures and the in vivo environment in anesthetized rats, measured using voltammetry. The architecture of DiscrimNet is described, and its ability to accurately predict in vitro and unseen in vivo concentrations is shown to vastly outperform a variety of shallow learning algorithms previously used for neurotransmitter discrimination. DiscrimNet is shown to generalize well to data captured from electrodes unseen during model training, eliminating the need to retrain the model for each new electrode. DiscrimNet is also shown to accurately predict the expected changes in dopamine and serotonin after cocaine and oxycodone administration in anesthetized rats in vivo. DiscrimNet therefore offers an exciting new method for real-time resolution of in vivo voltammetric signals into component neurotransmitters.

Parents of children with Down syndrome reflect on their postnatal diagnoses, 2003-2022.

A 2003 survey revealed the scope of mothers' dissatisfaction with their postnatal support following a diagnosis of Down syndrome (DS). Substantial proportions of mothers reported that providers conveyed diagnoses with pity, emphasized negative aspects of DS, and neglected to provide adequate materials explaining DS. This study follows up on the 2003 survey by assessing whether parents' experiences have improved. Four DS nonprofit organizations, which participated in the original study, distributed a mixed-methods survey to families who have had children with DS between 2003 and 2022. Quantitative analysis assessed correlations among responses and differences between the 2003 and 2022 survey groups. Open-ended responses were qualitatively analyzed. Compared to the 2003 findings, parents' perceptions of their postnatal care have not improved (N = 89). Parents are increasingly likely to report that their providers pitied them, omitted positive aspects of DS, and provided insufficient materials describing DS. Substantial proportions of parents reported fear (77%) and anxiety (79%), only 24% described receiving adequate explanatory materials, and parents were 45% likelier to report that physicians discussed negative aspects of DS than positive aspects. Qualitatively, substantial numbers of parents recounted insensitive conduct by providers. These results suggest that despite interventions, parents' experiences of postnatal diagnoses of DS have not improved over time. Certain provider behaviors-such as describing positive aspects of DS and providing comprehensive explanatory materials-can reduce fear and anxiety, pointing to directions for reform.

Navigating missing link: innovative cannulation for robotic mitral valve repair in the absence of inferior vena cava.

Cardiac surgeries often require the use of cardiopulmonary bypass to allow visualization and manipulation of tissues. Vascular anomalies may impose challenges with access configuration. A patient was evaluated for robot-assisted mitral valve repair and found to have an atretic inferior vena cava secondary due to chronic occlusion. The patient was cannulated arterially through the left common femoral artery, and two cannulation sites were applied for venous drainage: the right intrajugular vein and a second percutaneous access site directly into the right atrium through the chest wall. The procedure was completed without immediate complications, and the patient's perioperative course was unremarkable.

Bilayered extracellular matrix derived scaffolds with anisotropic pore architecture guide tissue organization during osteochondral defect repair.

While some clinical advances in cartilage repair have occurred, osteochondral (OC) defect repair remains a significant challenge, with current scaffold-based approaches failing to recapitulate the complex, hierarchical structure of native articular cartilage (AC). To address this need, we fabricated bilayered extracellular matrix (ECM)-derived scaffolds with aligned pore architectures. By modifying the freeze-drying kinetics and controlling the direction of heat transfer during freezing, it was possible to produce anisotropic scaffolds with larger pores which supported homogenous cellular infiltration and improved sulfated glycosaminoglycan deposition. Neo-tissue organization in vitro could also be controlled by altering scaffold pore architecture, with collagen fibres aligning parallel to the long-axis of the pores within scaffolds containing aligned pore networks. Furthermore, we used in vitro and in vivo assays to demonstrate that AC and bone ECM derived scaffolds could preferentially direct the differentiation of mesenchymal stromal cells (MSCs) towards either a chondrogenic or osteogenic lineage respectively, enabling the development of bilayered ECM scaffolds capable of spatially supporting unique tissue phenotypes. Finally, we implanted these scaffolds into a large animal model of OC defect repair. After 6 months in vivo, scaffold implantation was found to improve cartilage matrix deposition, with collagen fibres preferentially aligning parallel to the long axis of the scaffold pores, resulting in a repair tissue that structurally and compositionally was more hyaline-like in nature. These results demonstrate how scaffold architecture and composition can be spatially modulated to direct the regeneration of complex interfaces such as the osteochondral unit, enabling their use as cell-free, off-the-shelf implants for joint regeneration. STATEMENT OF SIGNIFICANCE: The architecture of the extracellular matrix, while integral to tissue function, is often neglected in the design and evaluation of regenerative biomaterials. In this study we developed a bilayered scaffold for osteochondral defect repair consisting of tissue-specific extracellular matrix (ECM)-derived biomaterials to spatially direct stem/progenitor cell differentiation, with a tailored pore microarchitecture to promote the development of a repair tissue that recapitulates the hierarchical structure of native AC. The use of this bilayered scaffold resulted in improved tissue repair outcomes in a large animal model, specifically the ability to guide neo-tissue organization and therefore recapitulate key aspects of the zonal structure of native articular cartilage. These bilayer scaffolds have the potential to become a new therapeutic option for osteochondral defect repair.