Zwitterionic imidazolium salts have been synthesized bearing alkylsulfonate and alkylcarboxylate
substituents and used as precursors to water-soluble metal−carbene complexes. Reaction of the zwitterionic
imidazolium compounds with Ag2O gave bis(imidazol-2-ylidene)silver complexes. These compounds
have been characterized spectroscopically and by electrospray mass spectrometry. A DMSO solvate of
bis[1-(2,6-diisopropylphenyl)-3-(3-sulfonatopropyl)imidazol-2-ylidene]silver sodium salt has been structurally characterized. In the solid state, this complex exists as a coordination polymer in which the sodium
ions bridge the sulfonate groups from two bis(imidazol-2-ylidene)silver moieties. Diiodobis[1-mesityl-3-(3-sulfonatopropyl)imidazol-2-ylidene]palladium disodium salt has also been prepared in low yield
and characterized by NMR spectroscopy and electrospray mass spectrometry.
Disorganization of the valve extracellular matrix (ECM) is a hallmark of calcific aortic valve disease (CAVD). However, while microarchitectural features of the ECM can strongly influence the biological and mechanical behavior of tissues, little is known about the ECM microarchitecture in CAVD. In this work, we apply advanced imaging techniques to quantify spatially heterogeneous changes in collagen microarchitecture in CAVD. Human aortic valves were obtained from individuals between 50 and 75 years old with no evidence of valvular disease (healthy) and individuals who underwent valve replacement surgery due to severe stenosis (diseased). Second Harmonic Generation microscopy and subsequent image quantification revealed layer-specific changes in fiber characteristics in healthy and diseased valves. Specifically, the majority of collagen fiber changes in CAVD were found to occur in the spongiosa, where collagen fiber number increased by over 2-fold, and fiber width and density also significantly increased. Relatively few fibrillar changes occurred in the fibrosa in CAVD, where fibers became significantly shorter, but did not otherwise change in terms of number, width, density, or alignment. Immunohistochemical staining for lysyl oxidase showed localized increased expression in the diseased fibrosa. These findings reveal a more complex picture of valvular collagen enrichment and arrangement in CAVD than has previously been described using traditional analysis methods. Changes in fiber architecture may play a role in regulating the pathobiological events and mechanical properties of valves during CAVD. Additionally, characterization of the ECM microarchitecture can inform the design of fibrous scaffolds for heart valve tissue engineering.
The concurrent use of WALANT and minor field sterility has created a hand surgery practice that is cost-effective for the patient and the facility and resulted in excellent patient outcomes and satisfaction.
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