Search results for "collage"
showing 10 items of 638 documents
Collagen metabolism of mouse skeletal muscle during the repair of exercise injuries.
1986
The activities of prolyl 4-hydroxylase and beta-glucuronidase, the concentration of hydroxyproline as well as reticulin and collagen type III, IV and V stainings were followed in skeletal muscle during a 20-day period after a 9-h treadmill running in untrained and trained male mice, aged 4-6 months. The prolonged 9-h running of untrained mice temporarily increased prolyl 4-hydroxylase activity 2, 5 and 10 days after exercise, more prominently in the red than in the white part of quadriceps femoris-muscle, and in analogical manner as beta-glucuronidase activity in tibialis anterior-muscle. Twenty days after exercise these enzymatic activities were back to the control level. The hydroxyprolin…
Hepatocyte growth factor/hepatopoietin A is expressed in fat-storing cells from rat liver but not myofibroblast-like cells derived from fat-storing c…
1992
Hepatocyte growth factor/hepatopoietin A is a complete mitogen for parenchymal liver cells, and its expression is increased as an early response to acute liver injury. To identify the liver cell population responsible for hepatocyte growth factor gene expression, we investigated tissue sections and isolated and purified cell fractions from normal rat liver by in situ and Northern blot hybridization. Hepatocyte growth factor transcripts were present in sinusoidal liver cells, which were preferentially located in the periportal parenchyma. Northern hybridization analysis of RNA isolated from purified liver cell fractions demonstrated that HGF messenger RNA is present only in fat-storing cells…
A collagen extraction and deuterium oxide stable isotope tracer method for the quantification of bone collagen synthesis rates in vivo.
2021
Abstract The development of safe and practical strategies to prevent weakening of bone tissue is vital, yet attempts to achieve this have been hindered by a lack of understanding of the short‐term (days‐weeks) physiology of bone collagen turnover. To address this, we have developed a method to quantify bone collagen synthesis in vivo, using deuterium oxide (D2O) tracer incorporation techniques combined with gas chromatography pyrolysis isotope‐ratio mass spectrometry (GC‐pyrolysis‐IRMS). Forty‐six male and female rats from a selectively bred model ingested D2O for 3 weeks. Femur diaphyses (FEM), tibia proximal (T‐PRO), and distal (T‐DIS) epiphyses‐metaphyses and tibia mid‐shaft diaphyses (T…
Long-Term Structural and Functional Myocardial Adaptations in Healthy Living Kidney Donors: A Pilot Study
2015
Background and Aims Compensatory renal hypertrophy following unilateral nephrectomy (UNX) occurs in the remaining kidney. However, the long-Term cardiac adaptive process to UNX remains poorly defined in humans. Our goal was to characterize myocardial structure and function in living kidney donors (LKDs), approximately 12 years after UNX. Methods and Results Cardiac function and structure in 15 Italian LKDs, at least 5 years after UNX (median time from donation = 8.4 years) was investigated and compared to those of age and sex matched U.S. citizens healthy controls (n = 15). Standard and speckle tracking echocardiography (STE) was performed in both LKDs and controls. Plasma angiotensin II, a…
Hyaluronic Acid Derivative with Improved Versatility for Processing and Biological Functionalization
2016
A hydrophobic/amino functionalized derivative of hyaluronic acid (HA-EDA-C18 ) has been processed by salt leaching technique as porous scaffold without need of chemical crosslinking. Aim of this work is to demonstrate the improved versatility of HA-EDA-C18 in terms of processing and biological functionalization. In particular, the chemical procedure to tether thiol bearing RGD peptide has been described. Moreover, the possibility to load and to control the release of slightly water soluble effectors has been demonstrated by using dexamethasone. First, the swelling and degradation profiles of the scaffolds have been investigated, then the evaluation of metabolic activity of bovine chondrocyt…
Dynamic Tuning of Viscoelastic Hydrogels with Carbonyl Iron Microparticles Reveals the Rapid Response of Cells to Three-Dimensional Substrate Mechani…
2021
Current methods to dynamically tune three-dimensional hydrogel mechanics require specific chemistries and substrates that make modest, slow, and often irreversible changes to their mechanical properties, exclude the use of protein-based scaffolds, or alter hydrogel microstructure and pore size. Here, we rapidly and reversibly alter the mechanical properties of hydrogels consisting of extracellular matrix proteins and proteoglycans by adding carbonyl iron microparticles (MP) and applying external magnetic fields. This approach drastically alters hydrogel mechanics: rheology reveals that application of a 4,000 Oe magnetic field to a 5 mg/mL collagen hydrogel containing 10 wt% MPs increases th…
Mechanical characterization of rose bengal and green light crosslinked collagen scaffolds for regenerative medicine
2021
Abstract Collagen is one of the most important biomaterials for tissue engineering approaches. Despite its excellent biocompatibility, it shows the non-negligible disadvantage of poor mechanical stability. Photochemical crosslinking with rose bengal and green light (RGX) is an appropriate method to improve this property. The development of collagen laminates is helpful for further adjustment of the mechanical properties as well as the controlled release of incorporated substances. In this study, we investigate the impact of crosslinking and layering of two different collagen scaffolds on the swelling behavior and mechanical behavior in micro tensile tests to obtain information on its wearin…
Metalloproteases meprin α and meprin β are C- and N-procollagen proteinases important for collagen assembly and tensile strength.
2013
Type I fibrillar collagen is the most abundant protein in the human body, crucial for the formation and strength of bones, skin, and tendon. Proteolytic enzymes are essential for initiation of the assembly of collagen fibrils by cleaving off the propeptides. We report that Mep1a −/− and Mep1b −/− mice revealed lower amounts of mature collagen I compared with WT mice and exhibited significantly reduced collagen deposition in skin, along with markedly decreased tissue tensile strength. While exploring the mechanism of this phenotype, we found that cleavage of full-length human procollagen I heterotrimers by either meprin α or meprin β led to the generation of mature collagen molecules that s…
Influence of saline and pH on collagen type I fibrillogenesis in vitro: Fibril polymorphism and colloidal gold labelling
2007
We have produced different collagen type I fibrils by in vitro fibrillogenesis of acetic acid-soluble collagen within the pH range 2.5-9.0, in the presence and absence of 150 mM NaCl. The varying relatively stable molecular assemblies and polymorphic fibrillar end-products produced after 24 h incubation have been assessed and compared by the TEM study of specimens negatively stained with uranyl acetate. In the presence of 150 mM NaCl, the assembly of collagen at low pH (2.5) leads to the formation of initial molecular aggregates that progressively link together at slightly higher pH (5.0) to form sub-fibrils and spindle-shaped D-banded bundles of sub-fibrils. At pH 6.0 these D-banded bundle…
Assessment of age-related skin changes using hyperspectral polarization imaging
2019
Abstract We report a development of hyperspectral polarization imaging approach for assessment of age-related skin changes. The degree of residual polarization is used as a quantitative marker of the age-related pathological malformations. The developed approach in frame of express analysis of the degree of residual polarization in each pixel of the image are shown.