scholarly journals Decellularization, Stabilization and Functionalization of Collagenous Tissues Used as Cardiovascular Biomaterials

10.5772/25184 ◽  
2011 ◽  
Author(s):  
Birzabith Mendoza-Novelo ◽  
Juan Valerio
Keyword(s):  
Cardiovascular Biomaterials ◽  
Collagenous Tissues

Electron Microscopic and Isozyme Study of a Case of Ochronosis

1972 ◽  
Vol 30 ◽  
pp. 88-89
Author(s):  
Jay W. Cha ◽  
Perry J. Melnick
Keyword(s):  
Benzene Ring ◽  
Enzyme System ◽  
Homogentisic Acid ◽  
Degenerative Changes ◽  
Acid Oxidase ◽  
Electron Microscopic ◽  
Tyrosine Metabolism ◽  
Collagenous Tissues

Hereditary ochronosis in very few cases has been examined electron microscopically or histochemically. In this disease homogentisic acid, a normal intermediary of tyrosine metabolism, forms in excessive amounts. This is believed to be due to absence or defective activity of homogentisic acid oxidase, an enzyme system necessary to break the benzene ring and to further break it down to fumaric and acetoacetic acids. Ochronotic pigment, a polymerized form of homogentisic acid, deposits mainly in mesenchymal tissues. There has been a question whether the pigment originates from the collagenous tissues, or deposits passively, where in contrast to melanin it induces degenerative changes.

ChemInform Abstract: Chromium-Induced Molecular Assemblies and Long Range Ordering in Collagenous Tissues: A Conceptual Insight into Chromium Tanning

ChemInform ◽  
2010 ◽  
Vol 30 (29) ◽  
pp. no-no
Author(s):  
R. Gayatri ◽  
Rama Rajaram ◽  
Balachandran Unni Nair ◽  
F. Chandrasekaran ◽  
T. Ramasami
Keyword(s):  
Long Range ◽  
Molecular Assemblies ◽  
Long Range Ordering ◽  
Collagenous Tissues ◽  
Insight Into

Stress Dependent Collagen Fibril Diameter Distribution in Human Aortic Valves

2007 ◽  
Author(s):  
Angelique Balguid ◽  
Anita Mol ◽  
Niels Driessen ◽  
Carlijn Bouten ◽  
Frank Baaijens
Keyword(s):  
Mechanical Properties ◽  
Collagen Fibril ◽  
Diameter Distribution ◽  
Connective Tissues ◽  
Aortic Valves ◽  
Cross Links ◽  
Fibril Morphology ◽  
Stress Dependent ◽  
Collagenous Tissues ◽  
Fibril Diameter

The mechanical properties of collagenous tissues are known to depend on a wide variety of factors, such as the type of tissue and the composition of its extracellular matrix. Relating mechanical roles to individual matrix components in such a complex system is difficult, if not impossible. However, as collagen is the main load bearing component in connective tissues, the relation between collagen and tissue biomechanics has been studied extensively in various types of tissues. The type of collagen, the amount and type of inter- and intramolecular covalent cross-links and collagen fibril morphology are involved in the tissues mechanical behavior (Beekman et al., 1997; Parry et al., 1978; Avery and Bailey, 2005). From literature it is known that the the collagen fibril diameter distribution can be directly related to the mechanical properties of the tissue. In particular, the diameter distribution of collagen fibrils is largely determined by the tissues requirement for tensile strength and elasticity (Parry et al., 1978).

Osteogenesis Imperfecta: Molecular and Mesoscale Disease Mechanisms

2009 ◽  
Author(s):  
Alfonso Gautieri ◽  
Sebastien Uzel ◽  
Simone Vesentini ◽  
Alberto Redaelli ◽  
Markus J. Buehler
Keyword(s):  
Mechanical Properties ◽  
Osteogenesis Imperfecta ◽  
Multiple Scales ◽  
Genetic Disorder ◽  
Single Point ◽  
Single Point Mutation ◽  
Mesoscale Simulation ◽  
Disease Mechanisms ◽  
Multiple Length Scales ◽  
Collagenous Tissues

Osteogenesis Imperfecta (OI) is a genetic disorder in collagen characterized by mechanically weakened tendon and fragile bones that affects more than 1 in 10,000 individuals. Even though many studies have attempted to associate specific mutation types with phenotypic severity, the mechanisms by which a single point mutation influences the mechanical behavior of tissues at multiple length-scales remain unknown. Here we show by a hierarchy of full atomistic and mesoscale simulation that OI mutations severely compromise the mechanical properties of collagenous tissues at multiple scales, from single molecules to collagen fibrils.

scholarly journals Alkaptonuria with extensive ochronotic degeneration of the Achilles tendon and its surgical treatment: a case report and literature review

2021 ◽  
Vol 15 (3) ◽  
pp. 129-136
Author(s):  
Nesrin Mwafi ◽  
Ali Alasmar ◽  
Monther Al-Momani ◽  
Sattam Alazaydeh ◽  
Omar Alajoulin ◽  
...  
Keyword(s):  
Case Report ◽  
Surgical Treatment ◽  
Achilles Tendon ◽  
Tendon Repair ◽  
Functional Results ◽  
Sudden Onset ◽  
Flexor Hallucis Longus ◽  
History Of ◽  
Complete Disruption ◽  
Collagenous Tissues

Abstract Background Alkaptonuria is a rare genetic metabolic disorder due to deficiency of homogentisate 1,2-dioxygenase (HGD), an enzyme catalyzing the conversion of homogentisate to 4-maleylacetoacetate in the pathway for the catabolism of phenylalanine and tyrosine. HGD deficiency results in accumulation of homogentisic acid and its pigmented polymer. Ochronosis is a bluish-black discoloration due to the deposition of the polymer in collagenous tissues. Extensive ochronotic involvement of the Achilles tendon in alkaptonuria and its surgical treatment is rarely reported. Case report A 43-year-old man presented to our clinic in March 2019 with sudden onset of left Achilles tendon pain with no history of prior trauma. Surgical exploration revealed a complete disruption of the tendon at its attachment to the calcaneus. Black pigmentation was extensive and reached the calcaneal tuberosity, extending about 7 cm from the insertion. Discussion Achilles reconstruction was performed using flexor hallucis longus tendon transfer. The patient experienced uncomplicated healing with satisfactory functional results. Conclusion Orthopedic surgeons should be aware of the progressive nature of alkaptonuria. Extensive degenerative changes of the ruptured tendon should be suspected so that physicians can plan tendon repair and facilitate prompt surgical intervention.

scholarly journals Publisher Correction: Tear resistance of soft collagenous tissues

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Kevin Bircher ◽  
Manuel Zündel ◽  
Marco Pensalfini ◽  
Alexander E. Ehret ◽  
Edoardo Mazza
Keyword(s):  
Collagenous Tissues ◽  
Tear Resistance

Crinoid functional morphology

1997 ◽  
Vol 3 ◽  
pp. 45-68 ◽  
Author(s):  
Tomasz K. Baumiller
Keyword(s):  
Functional Morphology ◽  
Nearest Neighbors ◽  
Bilateral Symmetry ◽  
Dominant Mode ◽  
Natural Setting ◽  
Particle Capture ◽  
Oral Side ◽  
Directional Flow ◽  
Collagenous Tissues ◽  
Tube Feet

Recent advances in crinoid functional morphology have been concentrated predominantly in two areas, one involving the study of mutable collagenous tissues (MCTs), and the other dealing with the implications of crinoids' rheophilic nature. The presence of MCTs in crinoid cirri and stalks, and their importance to the function of these structures has been demonstrated in several studies. It has been recently reported that MCTs have contractile properties (Birenheide and Motokawa, 1996); if this is corroborated, it would help resolve many fundamental problems in crinoid functional morphology. Studies of the crinoids in their natural setting have confirmed their predominantly rheophilic nature. The application of the rheophilic paradigm and the principles of physics and engineering to crinoids has provided insights into several areas of crinoid functional morphology, including: (1) mechanics of particle interception—direct interception (and not sieving) as the dominant mode of particle capture by the tube feet (no mucus net); (2) the importance of feeding posture and orientation—(a) bilateral symmetry of the feeding posture (oral side downcurrent), (b) the problems associated with maintaining such a posture under bi- or multi-directional flow (swiveling of pinnules, arms, and /or entire filters); (3) the effect of filter resistivity on fluid interception—solid filters need high ambient current velocities; and (4) the influence of nearest neighbors on fluid interception—side-by-side neighbors might be favored over upstream–downstream neighbors.

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