Home About us Contact
|
Home About us Contact | ||
|
|
||
Collagen Concentrations (collagen + concentration)
Selected AbstractsCollagen content and architecture of the pectoralis muscle in male chicks and broilers reared under various nutritional conditionsANIMAL SCIENCE JOURNAL, Issue 2 2010Chamali DAS ABSTRACT Varying chicken growth rates were induced with different nutritional regimes, and the collagen content and architecture of M. pectoralis (PT) were compared among 21-day-old chicks and broilers at 80 or 95 days of age. The percentage of muscle weight to live weight was higher in rapid growing chicks (8.4%) than slow growing chicks (6.3%). The 80-day-old broilers engaged in compensatory growth after the early slow growth period producing PT muscle at 11% of live weight. The 80- and 95-day-old chicks with restricted late growth after an early rapid growth period showed PT weight at 8% and 9% of live weight, respectively. Collagen content of the PT muscle markedly decreased from the chicks to the broilers. The collagen concentration was higher in the late-growth restricted broilers (1.67,1.88 mg/g) than the compensatory growth broilers (1.01,1.10 mg/g). Collagen concentration did not differ between the rapid and slow growing chicks (2.72 and 2.94 mg/g). Scanning electron micrographs showed thick and thin perimysia, and honeycomb endomysia. In the perimysia, a stack layer of collagen platelets and a reticular layer of collagen fiber cords were distinguished and collagen baskets of adipocytes were observed. The perimysial collagen fibers became thicker during growth of the chicks to broilers. However, in the late-growth restricted broilers, the perimysial collagen fibers seemed to have retarded development compared with the compensatory growth birds. The PT muscle of chickens develops optimally when body growth is enhanced. The PT muscle of the compensatory growth broilers had improved collagen architecture regardless of the marked decrease in collagen content. [source] Gender-specific differences in temporomandibular retrodiscal tissues of the goatEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2000Angelo Mariotti Healthy, adult, male and female goat temporomandibular retrodiscal tissues were characterized to determine if biochemical differences existed between the genders. RNA concentrations were not different between male and female retrodiscal tissues; however, the DNA concentration in female retrodiscal tissues was 82% greater than in male retrodiscal tissues. Collagen concentrations were significantly greater in male retrodiscal tissues, and this was reflected in significant gender differences of type I and III collagen concentrations. More specifically, male temporomandibular retrodiscal tissues contained 70% more type I collagen and 119% more type III collagen when compared to female retrodiscal tissues. These differences in collagens and DNA reflect a gender difference in temporomandibular retrodiscal tissue composition that underlies divergent biomechanical and neurophysiological properties. [source] Encapsulation of adult human mesenchymal stem cells within collagen-agarose microenvironments,BIOTECHNOLOGY & BIOENGINEERING, Issue 4 2005Anna Batorsky Abstract Reliable control over the process of cell differentiation is a major challenge in moving stem cell-based therapies forward. The composition of the extracellular matrix (ECM) is known to play an important role in modulating differentiation. We have developed a system to encapsulate adult human mesenchymal stem cells (hMSC) within spherical three-dimensional (3D) microenvironments consisting of a defined mixture of collagen Type I and agarose polymers. These protein-based beads were produced by emulsification of liquid hMSC-matrix suspensions in a silicone fluid phase and subsequent gelation to form hydrogel beads, which were collected by centrifugation and placed in culture. Bead size and size distribution could be varied by changing the encapsulation parameters (impeller speed and blade separation), and beads in the range of 30,150 microns in diameter were reliably produced. Collagen concentrations up to 40% (wt/wt) could be incorporated into the bead matrix. Visible light and fluorescence microscopy confirmed that the collagen matrix was uniformly distributed throughout the beads. Cell viability post-encapsulation was in the range of 75,90% for all bead formulations (similar to control slab gels) and remained at this level for 8 days in culture. Fluorescent staining of the actin cytoskeleton revealed that hMSC spreading increased with increasing collagen concentration. This system of producing 3D microenvironments of defined matrix composition therefore offers a way to control cell-matrix interactions and thereby guide hMSC differentiation. The bead format allows the use of small amounts of matrix proteins, and such beads can potentially be used as a cell delivery vehicle in tissue repair applications. © 2005 Wiley Periodicals, Inc. [source] Intracellular Na+ and Ca2+ modulation increases the tensile properties of developing engineered articular cartilageARTHRITIS & RHEUMATISM, Issue 4 2010Roman M. Natoli Objective Significant collagen content and tensile properties are difficult to achieve in tissue-engineered articular cartilage. The aim of this study was to investigate whether treating developing tissue-engineered cartilage constructs with modulators of intracellular Na+ or Ca2+ could increase collagen concentration and construct tensile properties. Methods Inhibitors of Na+ ion transporters and stimulators of intracellular Ca2+ were investigated for their ability to affect articular cartilage development in a scaffoldless, 3-dimensional chondrocyte culture. Using a systematic approach, we applied ouabain (Na+/K+ -ATPase inhibitor), bumetanide (Na+/K+/2Cl, tritransporter inhibitor), histamine (cAMP activator), and ionomycin (a Ca2+ ionophore) to tissue-engineered constructs for 1 hour daily on days 10,14 of culture and examined the constructs at 2 weeks or 4 weeks. The gross morphology, biochemical content, and compressive and tensile mechanical properties of the constructs were assayed. Results The results of these experiments showed that 20 ,M ouabain, 0.3 ,M ionomycin, or their combination increased the tensile modulus by 40,95% compared with untreated controls and resulted in an increased amount of collagen normalized to construct wet weight. In constructs exposed to ouabain, the increased percentage of collagen per construct wet weight was secondary to decreased glycosaminoglycan production on a per-cell basis. Treatment with 20 ,M ouabain also increased the ultimate tensile strength of neo-tissue by 56,86% at 4 weeks. Other construct properties, such as construct growth and type I collagen production, were affected differently by Na+ modulation with ouabain versus Ca2+ modulation with ionomycin. Conclusion These data are the first to show that treatments known to alter intracellular ion concentrations are a viable method for increasing the mechanical properties of engineered articular cartilage and identifying potentially important relationships to hydrostatic pressure mechanotransduction. Ouabain and ionomycin may be useful pharmacologic agents for increasing tensile integrity and directing construct maturation. [source] Encapsulation of adult human mesenchymal stem cells within collagen-agarose microenvironments,BIOTECHNOLOGY & BIOENGINEERING, Issue 4 2005Anna Batorsky Abstract Reliable control over the process of cell differentiation is a major challenge in moving stem cell-based therapies forward. The composition of the extracellular matrix (ECM) is known to play an important role in modulating differentiation. We have developed a system to encapsulate adult human mesenchymal stem cells (hMSC) within spherical three-dimensional (3D) microenvironments consisting of a defined mixture of collagen Type I and agarose polymers. These protein-based beads were produced by emulsification of liquid hMSC-matrix suspensions in a silicone fluid phase and subsequent gelation to form hydrogel beads, which were collected by centrifugation and placed in culture. Bead size and size distribution could be varied by changing the encapsulation parameters (impeller speed and blade separation), and beads in the range of 30,150 microns in diameter were reliably produced. Collagen concentrations up to 40% (wt/wt) could be incorporated into the bead matrix. Visible light and fluorescence microscopy confirmed that the collagen matrix was uniformly distributed throughout the beads. Cell viability post-encapsulation was in the range of 75,90% for all bead formulations (similar to control slab gels) and remained at this level for 8 days in culture. Fluorescent staining of the actin cytoskeleton revealed that hMSC spreading increased with increasing collagen concentration. This system of producing 3D microenvironments of defined matrix composition therefore offers a way to control cell-matrix interactions and thereby guide hMSC differentiation. The bead format allows the use of small amounts of matrix proteins, and such beads can potentially be used as a cell delivery vehicle in tissue repair applications. © 2005 Wiley Periodicals, Inc. [source] Gender-specific differences in temporomandibular retrodiscal tissues of the goatEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2000Angelo Mariotti Healthy, adult, male and female goat temporomandibular retrodiscal tissues were characterized to determine if biochemical differences existed between the genders. RNA concentrations were not different between male and female retrodiscal tissues; however, the DNA concentration in female retrodiscal tissues was 82% greater than in male retrodiscal tissues. Collagen concentrations were significantly greater in male retrodiscal tissues, and this was reflected in significant gender differences of type I and III collagen concentrations. More specifically, male temporomandibular retrodiscal tissues contained 70% more type I collagen and 119% more type III collagen when compared to female retrodiscal tissues. These differences in collagens and DNA reflect a gender difference in temporomandibular retrodiscal tissue composition that underlies divergent biomechanical and neurophysiological properties. [source] The P2Y1 receptor plays an essential role in the platelet shape change induced by collagen when TxA2 formation is preventedJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 6 2004P. Mangin Summary., ADP and TxA2 are secondary agonists which play an important role as cofactors when platelets are activated by agonists such as collagen or thrombin. The aim of the present study was to characterize the role of the ADP receptor P2Y1 in collagen-induced activation of washed platelets. Inhibition of P2Y1 alone with the selective antagonist MRS2179 prolonged the lag phase preceding aggregation in response to low or high concentrations of fibrillar collagen, without affecting the maximum amplitude of aggregation or secretion. A combination of MRS2179 and aspirin resulted in complete inhibition of platelet shape change at low and high collagen concentrations, together with a profound decrease in aggregation and secretion. Scanning electron microscopy showed that these platelets had conserved the discoid morphology typical of the resting state. A lack of shape change was also observed in aspirin-treated P2Y1 - and G,q -deficient mouse platelets and in ,-storage pool-deficient platelets from Fawn Hooded rats. In contrast, when the second ADP receptor P2Y12 was inhibited with AR-C69931MX, aspirin-treated platelets were still able to change shape and displayed only a moderate decrease in aggregation and secretion. In conclusion, this study provides evidence that collagen requires not only the TxA2 receptor Tp,, but also P2Y1, to induce platelet shape change. [source] | |||||||||||||