Scattering of Light from Histologic Sections: A New Method for the Analysis of Connective Tissue

We have developed a light scattering technique that can be used to analyze the orientation and diameter of collagen fibers in histologic sections of connective tissue. Scattering patterns obtained by transmitting laser light through sections of tissue contain information both on the orientation, degree of alignment, and size of the constituent collagen fibers. Analysis of the azimuthal intensity distribution of scattered light yields numerical values of the degree of alignment by use of an orientation index, S, which is chosen to vary between 0 for randomly oriented fibers and 1 for a perfectly aligned arrangement. The average diameter of the collagen fibers is calculated from the scattering angle at which the intensity reaches its first minimum. These measurements are independent of the nature of histologic stain. The procedure is illustrated by measurements obtained with sections of the guinea pig dermis and of control scar. We conclude from our experiments that light scattering can complement the analysis of tissue architecture typically performed with the light microscope

Regeneration of injured skin and peripheral nerves requires control of wound contraction, not scar formation

We review the mounting evidence that regeneration is induced in wounds in skin and peripheral nerves by a simple modification of the wound healing process. Here, the process of induced regeneration is compared to the other two well-known processes by which wounds close, i.e., contraction and scar formation. Direct evidence supports the hypothesis that the mechanical force of contraction (planar in skin wounds, circumferential in nerve wounds) is the driver guiding the orientation of assemblies of myofibroblasts (MFB) and collagen fibers during scar formation in untreated wounds. We conclude that scar formation depends critically on wound contraction and is, therefore, a healing process secondary to contraction. Wound contraction and regeneration did not coincide during healing in a number of experimental models of spontaneous (untreated) regeneration described in the literature. Furthermore, in other studies in which an efficient contraction-blocker, a collagen scaffold named dermis regeneration template (DRT), and variants of it, were grafted on skin wounds or peripheral nerve wounds, regeneration was systematically observed in the absence of contraction. We conclude that contraction and regeneration are mutually antagonistic processes. A dramatic change in the phenotype of MFB was observed when the contraction-blocking scaffold DRT was used to treat wounds in skin and peripheral nerves. The phenotype change was directly observed as drastic reduction in MFB density, dispersion of MFB assemblies and loss of alignment of the long MFB axes. These observations were explained by the evidence of a surface-biological interaction of MFB with the scaffold, specifically involving binding of MFB integrins α[subscript 1]β[subscript 1] and α[subscript 2]β[subscript 1] to ligands GFOGER and GLOGER naturally present on the surface of the collagen scaffold. In summary, we show that regeneration of wounded skin and peripheral nerves in the adult mammal can be induced simply by appropriate control of wound contraction, rather than of scar formation.National Institutes of Health (U.S.) (Grant RO1 NS051320)National Institutes of Health (U.S.) (Grant 5‐P41‐EB015871‐28)Horizon 2020 Framework Programme (European Commission) (Grant DLV‐658850)Singapore-MIT Alliance for Research and Technology (SMART) (Grant 5‐P41‐EB015871‐28)Hamamatsu Corporatio

Social Media Battles: their Impact during the 2014 Greek Municipal Elections

The purpose of this study is to examine the use of social media such as Facebook, Twitter, and YouTube by candidates running for the 2014 Greek Municipal Elections by addressing the following questions: (1) which factors affect social media adoption by municipal candidates?, and (2) whether social media usage along with the popularity of candidates' social media pages influence candidates' vote share. Results indicate that social media are not very popular campaigning tools among municipal candidates in Greece. This implies that Greek candidates still rely on traditional ways to lure their voters. Furthermore, findings reveal that candidates running in large municipalities are more likely to utilize social media (i.e., Facebook, Twitter, and YouTube) as means of political marketing. In addition, challengers seem to prefer Facebook and Twitter as campaign tools while males tend to focus on YouTube to attract voters. Despite the low adoption rate, results suggest that candidates who made use of social media won more votes compared to candidates who were not social media users. Moreover, it was found that a candidate's Facebook page and YouTube channel popularity are good indicators of the candidate's vote share

Quantifying the surface chemistry of 3D matrices in situ

Despite the major role of the matrix (the insoluble environment around cells) in physiology and pathology, there are very few and limited methods that can quantify the surface chemistry of a 3D matrix such as a biomaterial or tissue ECM. This study describes a novel optical-based methodology that can quantify the surface chemistry (density of adhesion ligands for particular cell adhesion receptors) of a matrix in situ. The methodology utilizes fluorescent analogs (markers) of the receptor of interest and a series of binding assays, where the amount of bound markers on the matrix is quantified via spectral multi-photon imaging. The study provides preliminary results for the quantification of the ligands for the two major collagen-binding integrins (α[subscript 1]β[subscript 1], α[subscript 2]β[subscript 1]) in porous collagen scaffolds that have been shown to be able to induce maximum regeneration in transected peripheral nerves. The developed methodology opens the way for quantitative descriptions of the insoluble microenvironment of cells in physiology and pathology, and for integrating the matrix in quantitative models of cell signaling.National Institutes of Health (U.S.) (RO1 NS051320)Singapore-MIT Alliance for Research and Technolog

Dirbtinės odos Integra™ naudojimas gydant didelius melanocitinius apgamus

Melanocytic nevi are congenital, benign, pigmented proliferations. They have high risk of malignancy, most frequently transform to malignant skin melanoma and 70% it occurs in the first life decade. The risk of malignant transformation increases proportionately to their size. The best way to avoid those risks is early and radical excision. In 1996 on the market appeared the Integra™ artificial skin, has made it possible to improve the methods for the elimination of large congenital nevi and significantly reduce the risk of malignant melanoma, at an early age. 2011–2019, in Children’s Hospital, Affiliate of Vilnius University Hospital Santaros Clinics, the Integra™ was used to treat congenital melanocytic nevi in four children. Implantation of the skin substitute Integra™ has been successful for all the patients, the prognosis was good. The treatment of congenital melanocytic nevi is a necessity to avoid the risk of developing malignant melanoma. The rarity of this condition has led to the fact that so far there is no universal approach for all the cases. Integra™ artificial skin is an excellent choice for the treatment of congenital melanocytic nevi, especially for paediatric patients.Melanocitiniai apgamai – įgimti gerybiniai pigmentiniai dariniai, turintys didelę piktybinio naviko išsivystymo riziką. Šie dariniai dažniausiai transformuojasi į piktybinę odos melanomą. 70 proc. atvejų tai įvyksta per pirmąjį gyvenimo dešimtmetį. Apgamų piktybiškumo rizika didėja proporcingai jų dydžiui. Norint transformacijos išvengti, būtinas ankstyvas ir radikalus šių darinių pašalinimas. 1996 m. rinkoje pasirodžiusi dirbtinė oda Integra™ suteikė galimybę patobulinti didelių įgimtų apgamų pašalinimo metodus ir jau ankstyvoje vaikystėje smarkiai sumažinti piktybinės melanomos riziką. 2011–2019 m. Vaikų ligoninėje, Vilniaus universiteto ligoninės Santaros klinikos filiale, Integra™ panaudota gydant įgimtus melanocitinius apgamus keturiems vaikams. Odos pakaitalo Integra™ implantacija visiems pacientams buvo sėkminga, prognozė gera. Įgimtų melanocitinių apgamų gydymas reikšmingai sumažina piktybinės melanomos išsivystymo riziką. Būklė gana reta, todėl iki šiol nėra nė vieno visiems tinkamo metodo. Integra™ dirbtinė oda yra puikus pasirinkimas gydant įgimtus melanocitinius apgamus, ypač pediatriniams pacientams

PERANCANGAN SISTEM INFORMASI GEOGRAFIS DALAM PEMETAAN DAERAH YANG RAWAN DAN AMAN BENCANA ALAM DI DAERAH ISTIMEWA YOGYAKARTA BERBASIS WEB

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Healing of Tendon Defects Implanted with a Porous Collagen-GAG Matrix: Histological Evaluation

There is currently no method to restore normal function in tendon injuries that result in a gap. The objective of this study was to evaluate the early healing of tendon defects implanted with a porous collagen–glycosaminoglycan (CG) matrix, previously shown to facilitate the regeneration of dermis and peripheral nerve. A novel animal model that isolates the tendon defect site from surrounding tissue during healing was employed. This model used a silicone tube to entubulate the surgically produced tendon gap of 10 mm, allowing for the evaluation of the effects of the analog of extracellular matrix on healing of tendon, absent the influences of the external environment. The results showed that tendon stumps induced synthesis of a tissue cable inside the silicone tube in both the presence and absence of CG matrix. The presence of the CG matrix, however, altered the process of tendon healing. Tubes filled with CG matrix contained a significantly greater volume of tissue at the time periods of evaluation: 3, 6, and 12 weeks. Granulation tissue persisted for a longer period of time in the lesion site of CG-filled defects, and the amount of dense fibrous tissue increased continuously during the period of study in defects filled with CG matrix. In contrast, the amount of dense fibrous tissue decreased after 6 weeks in originally empty tubes. In tubes that did not contain the CG matrix, the new tissue consisted of dense aggregates of crimped fibers with a wavelength and fiber bundle thickness that were significantly shorter than those in normal tendon, and consistent with the type of scar that is the end result of repair of many connective tissues. Although, CG-filled tubes contained dense fibrous tissue by 12 weeks, the tissue had no crimp. The CG matrix may have prolonged the synthesis of granulation tissue and delayed or prevented the formation of scar.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63265/1/ten.1997.3.187.pd