Predictors of Cryptococcus gattii clinical presentation and outcome: An international study.

Background: Infection by Cryptococcus gattii can lead to pulmonary or central nervous system (CNS) disease, or both. Whether site of infection and disease severity are associated with C. gattii species and lineages or with certain underlying medical conditions, or both is unclear.

Photochemical Control of Network Topology in PEG Hydrogels.

Hydrogels are often synthesized through photoinitiated step-, chain-, and mixed-mode polymerizations, generating diverse network topologies and resultant material properties that depend on the underlying network connectivity. While many photocrosslinking reactions are available, few afford controllable connectivity of the hydrogel network. Herein, a versatile photochemical strategy is introduced for tuning the structure of poly(ethylene glycol) (PEG) hydrogels using macromolecular monomers functionalized with maleimide and styrene moieties.

Fully synthetic hydrogels promote robust crypt formation in intestinal organoids.

Initial landmark studies in the design of synthetic hydrogels for intestinal organoid culture identified precise matrix requirements for differentiation, namely decompression of matrix-imposed forces and supplementation of laminin. But beyond stating the necessity of laminin, organoid-laminin interactions have gone largely unstudied, as this ubiquitous requirement of exogenous laminin hinders investigation. In this work, we exploit a fast stress relaxing, boronate ester based synthetic hydrogel for the culture of intestinal organoids, and fortuitously discover that unlike all other synthetic hydrogels to date, laminin does not need to be supplemented for crypt formation.

Reversible Intracellular Gelation of MCF10A Cells Enables Programmable Control Over 3D Spheroid Growth.

In nature, some organisms survive extreme environments by inducing a biostatic state wherein cellular contents are effectively vitrified. Recently, a synthetic biostatic state in mammalian cells is achieved via intracellular network formation using bio-orthogonal strain-promoted azide-alkyne cycloaddition (SPAAC) reactions between functionalized poly(ethylene glycol) (PEG) macromers. In this work, the effects of intracellular network formation on a 3D epithelial MCF10A spheroid model are explored.

Using linked data to identify pathways of reporting overdose events in British Columbia, 2015-2017.

Introduction: Overdose events related to illicit opioids and other substances are a public health crisis in Canada. The BC Provincial Overdose Cohort is a collection of linked datasets identifying drug-related toxicity events, including death, ambulance, emergency room, hospital, and physician records. The datasets were brought together to understand factors associated with drug-related overdose and can also provide information on pathways of care among people who experience an overdose.

Photo-expansion microscopy enables super-resolution imaging of cells embedded in 3D hydrogels.

Hydrogels are extensively used as tunable, biomimetic three-dimensional cell culture matrices, but optically deep, high-resolution images are often difficult to obtain, limiting nanoscale quantification of cell-matrix interactions and outside-in signalling. Here we present photopolymerized hydrogels for expansion microscopy that enable optical clearance and tunable ×4.6-6.

Extracellular matrix stiffness controls cardiac valve myofibroblast activation through epigenetic remodeling.

Aortic valve stenosis (AVS) is a progressive fibrotic disease that is caused by thickening and stiffening of valve leaflets. At the cellular level, quiescent valve interstitial cells (qVICs) activate to myofibroblasts (aVICs) that persist within the valve tissue. Given the persistence of myofibroblasts in AVS, epigenetic mechanisms have been implicated.

Intracellular Crowding by Bio-Orthogonal Hydrogel Formation Induces Reversible Molecular Stasis.

To survive extreme conditions, certain animals enter a reversible protective stasis through vitrification of the cytosol by polymeric molecules such as proteins and polysaccharides. In this work, synthetic gelation of the cytosol in living cells is used to induce reversible molecular stasis. Through the sequential lipofectamine-mediated transfection of complementary poly(ethylene glycol) macromers into mammalian cells, intracellular crosslinking occurs through bio-orthogonal strain-promoted azide-alkyne cycloaddition click reactions.

Ocular mycobacterial lesions in cats.

Ocular mycobacterial infections are an under-recognized cause of morbidity in the domestic cat. This study aimed to explore the distribution, histopathological appearance, and severity of feline ocular mycobacterial lesions, and to characterize the immune cell population with immunohistochemistry. Routine histological staining with hematoxylin and eosin, and Masson's trichrome, was performed to identify ocular lesions and assign an inflammation score based on the number of cells present.

Using Stereochemistry to Control Mechanical Properties in Thiol-Yne Click-Hydrogels.

The stereochemistry of polymers has a profound impact on their mechanical properties. While this has been observed in thermoplastics, studies on how stereochemistry affects the bulk properties of swollen networks, such as hydrogels, are limited. Typically, changing the stiffness of a hydrogel is achieved at the cost of changing another parameter, that in turn affects the physical properties of the material and ultimately influences the cellular response.

Using Stereochemistry to Control Mechanical Properties in Thiol-Yne Click-Hydrogels.

The stereochemistry of polymers has a profound impact on their mechanical properties. While this has been observed in thermoplastics, studies on how stereochemistry affects the bulk properties of swollen networks, such as hydrogels, are limited. Typically, changing the stiffness of a hydrogel is achieved at the cost of changing another parameter, that in turn affects the physical properties of the material and ultimately influences the cellular response.

Photoclick Chemistry: A Bright Idea.

At its basic conceptualization, photoclick chemistry embodies a collection of click reactions that are performed via the application of light. The emergence of this concept has had diverse impact over a broad range of chemical and biological research due to the spatiotemporal control, high selectivity, and excellent product yields afforded by the combination of light and click chemistry. While the reactions designated as "photoclick" have many important features in common, each has its own particular combination of advantages and shortcomings.

MSG07: An International Cohort Study Comparing Epidemiology and Outcomes of Patients With Cryptococcus neoformans or Cryptococcus gattii Infections.

Background: Cryptococcosis due to Cryptococcus neoformans and Cryptococcus gattii varies with geographic region, populations affected, disease manifestations, and severity of infection, which impact treatment.

Methods: We developed a retrospective cohort of patients diagnosed with culture-proven cryptococcosis during 1995-2013 from 5 centers in North America and Australia. We compared underlying diseases, clinical manifestations, treatment, and outcomes in patients with C.

Charged Poly(-isopropylacrylamide) Nanogels for the Stabilization of High Isoelectric Point Proteins.

Storage and transportation of protein therapeutics using refrigeration is a costly process; a reliable electrical supply is vital, expensive equipment is needed, and unique transportation is required. Reducing the reliance on the cold chain would enable low-cost transportation and storage of biologics, ultimately improving accessibility of this class of therapeutics to patients in remote locations. Herein, we report on the synthesis of charged poly(-isopropylacrylamide) nanogels that efficiently adsorb a range of different proteins of varying isoelectric points and molecular weights (e.

Calcium Signaling Regulates Valvular Interstitial Cell Alignment and Myofibroblast Activation in Fast-Relaxing Boronate Hydrogels.

The role viscoelasticity in fibrotic disease progression is an emerging area of interest. Here, a fast-relaxing hydrogel system is exploited to investigate potential crosstalk between calcium signaling and mechanotransduction. Poly(ethylene glycol) (PEG) hydrogels containing boronate and triazole crosslinkers are synthesized, with varying ratios of boronate to triazole crosslinks to systematically vary the extent of stress relaxation.

Viscoelasticity of hydrazone crosslinked poly(ethylene glycol) hydrogels directs chondrocyte morphology during mechanical deformation.

Chondrocyte deformation influences disease progression and tissue regeneration in load-bearing joints. In this work, we found that viscoelasticity of dynamic covalent crosslinks temporally modulates the biophysical transmission of physiologically relevant compressive strains to encapsulated chondrocytes. Chondrocytes in viscoelastic alky-hydrazone hydrogels demonstrated (91.

Modelling the combined impact of interventions in averting deaths during a synthetic-opioid overdose epidemic.

Background And Aims: The province of British Columbia (BC) Canada has experienced a rapid increase in illicit drug overdoses and deaths during the last 4 years, with a provincial emergency declared in April 2016. These deaths have been driven primarily by the introduction of synthetic opioids into the illicit opioid supply. This study aimed to measure the combined impact of large-scale opioid overdose interventions implemented in BC between April 2016 and December 2017 on the number of deaths averted.

Development and characteristics of the Provincial Overdose Cohort in British Columbia, Canada.

Introduction: British Columbia (BC), Canada declared a public health emergency in April 2016 for opioid overdose. Comprehensive data was needed to identify risk factors, inform interventions, and evaluate response actions. We describe the development of an overdose cohort, including linkage strategy, case definitions, and data governance model, and present the resulting characteristics, including data linkage yields and case overlap among data sources.

Hydrogel and Organogel Formation by Hierarchical Self-Assembly of Cyclic Peptides Nanotubes.

Breaking away from the linear structure of previously reported peptide-based gelators, this study reports the first example of gel formation based on the use of cyclic peptides made of alternating d- and l-amino acids, known to self-assemble in solution to form long nanotubes. Herein, a library of cyclic peptides was systemically studied for their gelation properties in various solvents, uncovering key parameters driving both organogel and hydrogel formation. The hierarchical nature of the self-assembly process in water was characterised by a combination of electron microscopy imaging and small-angle X-ray scattering, revealing a porous network of entangled nanofibres composed by the aggregation of several cyclic peptide nanotubes.

Self-healing, stretchable and robust interpenetrating network hydrogels.

A self-healable stretchable hydrogel system that can be readily synthesized while also possessing robust compressive strength has immense potential for regenerative medicine. Herein, we have explored the addition of commercially available unfunctionalized polysaccharides as a route to synthesize self-healing, stretchable poly(ethylene glycol) (PEG) interpenetrating networks (IPNs) as extracellular matrix (ECM) mimics. The introduction of self-healing and stretchable properties has been achieved while maintaining the robust mechanical strength of the orginal, single network PEG-only hydrogels (ultimate compressive stress up to 2.

Comparison of qPCR versus culture for the detection and quantification of Clostridium difficile environmental contamination.

Contaminated surfaces serve as an important reservoir for Clostridium difficile transmission. Current strategies to detect environmental contamination of C. difficile rely heavily on culture, and often only indicate presence versus absence of spores.

Increased environmental sample area and recovery of Clostridium difficile spores from hospital surfaces by quantitative PCR and enrichment culture.

Objective: Clostridium difficile spores play an important role in transmission and can survive in the environment for several months. Optimal methods for measuring environmental C. difficile are unknown.

Design of synthetic extracellular matrices for probing breast cancer cell growth using robust cyctocompatible nucleophilic thiol-yne addition chemistry.

Controlled, three-dimensional (3D) cell culture systems are of growing interest for both tissue regeneration and disease, including cancer, enabling hypothesis testing about the effects of microenvironment cues on a variety of cellular processes, including aspects of disease progression. In this work, we encapsulate and culture in three dimensions different cancer cell lines in a synthetic extracellular matrix (ECM), using mild and efficient chemistry. Specifically, harnessing the nucleophilic addition of thiols to activated alkynes, we have created hydrogel-based materials with multifunctional poly(ethylene glycol) (PEG) and select biomimetic peptides.

Nonswelling Thiol-Yne Cross-Linked Hydrogel Materials as Cytocompatible Soft Tissue Scaffolds.

A key drawback of hydrogel materials for tissue engineering applications is their characteristic swelling response, which leads to a diminished mechanical performance. However, if a solution can be found to overcome such limitations, there is a wider application for these materials. Herein, we describe a simple and effective way to control the swelling and degradation rate of nucleophilic thiol-yne poly(ethylene glycol) (PEG) hydrogel networks using two straightforward routes: (1) using multiarm alkyne and thiol terminated PEG precursors or (2) introducing a thermoresponsive unit into the PEG network while maintaining their robust mechanical properties.

Precision Epitaxy for Aqueous 1D and 2D Poly(ε-caprolactone) Assemblies.

The fabrication of monodisperse nanostructures of highly controlled size and morphology with spatially distinct functional regions is a current area of high interest in materials science. Achieving this control directly in a biologically relevant solvent, without affecting cell viability, opens the door to a wide range of biomedical applications, yet this remains a significant challenge. Herein, we report the preparation of biocompatible and biodegradable poly(ε-caprolactone) 1D (cylindrical) and 2D (platelet) micelles in water and alcoholic solvents via crystallization-driven self-assembly.