Browsing by Subject "skin"

Now showing 1 - 6 of 6
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    Data from "Diverse Bacterial Communities Exist on Canine Skin and are Impacted by Cohabitation and Time"
    (2016-11-17) Johnson, Timothy; Torres, Sheila; Danzeisen, Jessica; Clayton, Jonathan; Ward, Tonya; Knights, Dan; Huang, Hu; joh04207@umn.edu; Johnson, Timothy
    This related study sampled 40 dogs from 20 households over the course of three seasons. Three skin sites were examined. The goal of the study was to determine if a core skin microbiome exists in dogs across time and body site, and if cohabitation impacts sharing of the skin microbiome. This dataset is a part of the Torres_Johnson Canine Microbiome Study.
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    The function of skin resident dendritic cells in CD4+ T cell differentiation
    (2016-08) Yao, Chen
    Skin-resident dendritic cells (DC) play a crucial role in initiation of adaptive immune responses against cutaneous pathogens as well as in the maintenance of peripheral tolerance. However, the immune response induced by skin DC against foreign antigen in the absence of adjuvants has not been addressed. Here we report that, using anti-huLangerin/ muLangerin antibodies, we could specifically target antigens to LC or CD103+ dermal DC. Targeting foreign peptide 2W1S by either LC or CD103+ dDC was sufficient for expansion of naïve CD4+ T cells and induction of T follicular helper cell (Tfh) differentiation. The expansion of Tfh specific to foreign peptide was accompanied by activation and expansion of antigen-specific B cells and the development of a robust antibody response that provided systemic protection against influenza infection. Using huLang LCΔMHC-II mice, we showed that CD4+ T cell proliferation was intact despite the MHC II deficiency on LC after targeting antigen to LC. We found that antigen targeted LC handed over antigen to CD11b+ dDC and DN dDC. We also showed MHC II deficient LC acquired MHC II in the lymph node through cross-dressing. This study reveals a major unappreciated function of skin DC in humoral response, and the communication between DC subsets, which provides insight into DC-targeted vaccine design.
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    Mechano-to-Neural Transduction of the Pacinian Corpuscle
    (2017-10) Quindlen, Julia
    Cutaneous mechanoreceptors are responsible for our ability to distinguish between different touch modalities and experience the physical world around us. Mechanoreceptors are innervated by afferent mechanosensitive neurons that transduce mechanical stimuli into action potentials and terminate in specialized end organs. The Pacinian corpuscle (PC) has been studied more than any of our other mechanoreceptors due to its large size and ease of identification during dissection. The PC, which is found primarily within the dermis of glabrous skin, responds to low-amplitude, high-frequency vibrations in the 20-1000 Hz range. The PC functions as a bandpass filter to vibrations, an effect attributed to the structural and mechanical complexity of its end organ. The PC contains a central mechanosensitive nerve fiber (neurite) that is encapsulated by alternating layers of flat, epithelial-type cells (lamellae) and fluid. The overarching goal of this thesis was to unify the anatomical and electrophysiological observations of the PC via a detailed mechanistic model of PC response to mechanical stimulation, requiring a multiphysics, multiscale approach. First, we developed a multiscale finite-element mechanical model to simulate the equilibrium response of the PC to indentation while accounting for the layered, anisotropic structure of the PC and its deep location within the skin. Next, we developed a three-stage finite-element model of the PC’s mechanical and neural responses to a vibratory input that accounted for the lamellar mechanics and neurite electrochemistry. This mechano-neural model was able to simulate the PC’s band-pass filtration of vibratory stimuli and rapid adaptation to sustained mechanical stimuli. We then used this model to evaluate the relationship between the PC’s material and geometric parameters and its response to vibration and developed dimensionless expressions for the relationship between these parameters and peak frequency or bandwidth. We then embedded multiple mechano-neural PC models within a finite-element model of human skin to simulate the mechanical and neural behavior of a PC cluster in vivo. We then performed a literature search to compile the structural parameters of PCs from various species and used our mechano-neural model to simulate the frequency response across species. Finally, we isolated PCs from human cadaveric hands and performed micropipette aspiration experiments to determine an apparent Young’s modulus of the PC. The computational and experimental work performed in this thesis contribute to the understanding of the fundamental behavior of mechanoreceptors, which is a necessary first step towards the development of haptic feedback-enabled devices.
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    Online Semantic Labeling of Deformable Tissues for Medical Applications
    (2017-05) O'Neill, John
    Surgery remains dangerous, and accurate knowledge of what is presented to the surgeon can be of great importance. One technique to automate this problem is non-rigid tracking of time-of-flight camera scans. This requires accurate sensors and prior information as well as an accurate non-rigid tracking algorithm. This thesis presents an evaluation of four algorithms for tracking and semantic labeling of deformable tissues for medical applications, as well as additional studies on a stretchable flexible smart skin and dynamic 3D bioprinting. The algorithms were developed and tested for this study, and were evaluated in terms of speed and accuracy. The algorithms tested were affine iterative closest point, nested iterative closest point, affine fast point feature histograms, and nested fast point feature histograms. The algorithms were tested against simulated data as well as direct scans. The nested iterative closest point algorithm provided the best balance of speed and accuracy while providing semantic labeling in both simulation as well as using directly scanned data. This shows that fast point feature histograms are not suitable for nonrigid tracking of geometric feature poor human tissues. Secondary experiments were also performed to show that the graphics processing unit provides enough speed to perform iterative closest point algorithms in real-time and that time of flight depth sensing works through an endoscope. Additional research was conducted on related topics, leading to the development of a novel stretchable flexible smart skin sensor and an active 3D bioprinting system for moving human anatomy.
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    Revealing Novel Skin Biology Using Protein-Trap Gene-Break Transposon Mutagenesis Technology In The Larval Zebrafish Model
    (2016-12) Westcot, Stephanie
    Abstract Although skin disorders affect as much as a third of the population at any given time, available treatments are limited. Because a more comprehensive understanding of skin development mechanisms can spur the identification of new treatment targets and techniques, we developed the Zebrafish Integument Project (ZIP), an expression-driven platform for identifying new skin genes and new, revertible phenotypes in the vertebrate model Danio rerio (zebrafish). In vivo selection for skin-specific expression of gene-break transposon (GBT) mutant lines identified eleven new, revertible GBT alleles of genes involved in skin development. Eight of those genes had been described in an integumentary context to varying degrees: fras1, grip1, hmcn1, msxc, col4a4, ahnak, capn12, and nrg2a. Three others—arhgef25b, fkbp10b, and megf6a—emerged as novel skin genes. Embryos homozygous for a GBT insertion in neuregulin 2a (nrg2a) revealed a novel requirement for a Neuregulin 2a (Nrg2a) – ErbB2/3 – AKT signaling pathway governing ridge cell morphogenesis and apicobasal organization during median fin fold (MFF) morphogenesis. In nrg2a mutant larvae, the basal keratinocytes that comprise the apical MFF (ridge cells) displayed reduced pAKT levels as well as reduced apical domains and exaggerated basolateral domains. Those defects prevented proper ridge cell elongation into a flattened epithelial morphology, resulting in thickened MFF edges. Additionally, morpholino knockdown of epithelial polarity regulator and tumor suppressor lgl2 ameliorated the nrg2a mutant phenotype. Identifying Lgl2 as an antagonist of Nrg2a – ErbB signaling revealed a significantly earlier role for Lgl2 during epidermal morphogenesis than has been described to date. Furthermore, our findings demonstrated that ridge cells’ squamous flattening morphogenesis drives apical MFF development. We therefore propose MFF ridge cells as a new model for investigating the regulation of cell polarity and cellular morphogenesis with regard to their roles as crucial mechanisms for epithelial morphogenesis generally, and for flattening morphogenesis in particular.
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    Your Guide to Treatment of Electrical, Chemical, and Thermal Burns
    (2008-02-05) Gauquie, Kimberly
    Thermal burns are assessed by depth of burn and percentage of body area involved. First and second degree thermal burns can often be cared for at home. Electrical and chemical burns can be prevented in the home through easy measures.