Structure and Strength of Bovine and Equine Amniotic Membrane.

Thin, strong scaffold materials are needed for surgical applications. New materials are required, particularly those readily available, such as from non-human sources. Bovine amniotic membrane (antepartum) and equine amniotic membrane (postpartum) were characterized with tear and tensile tests.

Collagen dehydration.

Type I collagen is a ubiquitous structural protein in animal tissues. It is normally present in a hydrated form. However, collagen is very dependent on associated water for its mechanical properties.

Pilot study on the effects of preservatives on corneal collagen parameters measured by small angle X-ray scattering analysis.

Objective: Small angle X-ray scattering (SAXS) analysis is a sensitive way of determining the ultrastructure of collagen in tissues. Little is known about how parameters measured by SAXS are affected by preservatives commonly used to prevent autolysis. We determined the effects of formalin, glutaraldehyde, Triton X and saline on measurements of fibril diameter, fibril diameter distribution, and D-spacing of corneal collagen using SAXS analysis.

Bovine Meniscus Middle Zone Tissue: Measurement of Collagen Fibril Behavior During Compression.

Background: Type I collagen is the major component of the extracellular matrix of the knee's meniscus and plays a central role in that joint's biomechanical properties. Repair and reconstruction of tissue damage often requires a scaffold to assist the body to rebuild. The middle zone of bovine meniscus is a material that may be useful for the preparation of extracellular matrix scaffolds.

Measured collagen fibril response to arterial inflation using SAXS.

Arteries are elastic structures containing both elastin and collagen. While the high content of elastin is understood to be important for the elasticity of arteries with systolic and diastolic pressure pulses, the role of collagen in the elastic properties of arteries is less understood. Here we use small angle X-ray scattering to investigate the changes in arrangement of collagen fibrils and the strain experienced by collagen fibrils as arteries are inflated.

Tropical Keratopathy (Florida Spots) in Cats.

The authors used microscopy and synchrotron-based small-angle X-ray scattering analysis (SAXS) to describe lesions macroscopically typical of tropical keratopathy ("Florida spots") from 6 cats on St Kitts. Microscopically, there were varying degrees of epithelial hyperplasia and thinning of the cornea (by 4% to 18%) due to loss of corneal stroma associated with dense accumulations of collagen in the superficial stroma. The collagen fibrils in lesions were wider and had more variable diameters (39.

Artificially modified collagen fibril orientation affects leather tear strength.

Background: Ovine leather has around half the tear strength of bovine leather and is therefore not suitable for high-value applications such as shoes. Tear strength has been correlated with the natural collagen fibril alignment (orientation index, OI). It is hypothesized that it could be possible to artificially increase the OI of the collagen fibrils and that an artificial increase in OI could increase tear strength.

Acellular dermal matrix collagen responds to strain by intermolecular spacing contraction with fibril extension and rearrangement.

Acellular dermal matrix (ADM) materials are used as scaffold materials in reconstructive surgery. The internal structural response of these materials in load-bearing clinical applications is not well understood. Bovine ADM is characterized by small-angle X-ray scattering while subjected to strain.

Collagen Fibril Response to Strain in Scaffolds from Ovine Forestomach for Tissue Engineering.

Scaffold biomaterials are typically applied surgically as reinforcement for weakened or damaged tissue, acting as substrates on which healing tissue can grow. Natural extracellular matrix (ECM) materials consisting mainly of collagen are often used for this purpose, but are anisotropic. Ovine forestomach matrix (OFM) ECM was exposed to increasing strain and synchrotron-based SAXS diffraction patterns and revealed that the collagen fibrils within underwent changes in orientation, orientation index (a measure of isotropy), and extension.

Collagen Fibril Intermolecular Spacing Changes with 2-Propanol: A Mechanism for Tissue Stiffness.

Materials composed primarily of collagen are important as surgical scaffolds and other medical devices and require flexibility. However, the factors that control the suppleness and flexibility of these materials are not well understood. Acellular dermal matrix materials in aqueous mixtures of 2-propanol were studied.

Deer leather: analysis of the microstructure affecting pebble.

Background: Deer leather has a characteristic pattern, referred to as 'pebble', which is accorded such importance that a lack of it renders a leather defective. Synchrotron-based small-angle X-ray scattering (SAXS), ultrasonic imaging, scanning electron microscopy, and tear tests were used to investigate the structural characteristics of well-pebbled and poorly pebbled cervine leathers.

Results: Poorly pebbled leather has a less open structure in the upper grain region than well-pebbled leather.

A small angle X-ray scattering study of the structure and development of looseness in bovine hides and leather.

Background: Some bovine hides produce poor quality leather, termed loose leather. The structural characteristics of hides and the intermediate processed stages that lead to loose leather are not well understood. In the present study, synchrotron-based small angle X-ray scattering (SAXS) is used to investigate collagen fibril orientation at the different stages of processing (i.

Collagen Fibril Structure and Strength in Acellular Dermal Matrix Materials of Bovine, Porcine, and Human Origin.

Strength is an important characteristic of acellular dermal matrix (ADM) materials used for surgical scaffolds. Strength depends on the material's structure, which may vary with the source from which the product is produced, including species and animal age. Here, variations in the physical properties and structures of ADM materials from three species are investigated: bovine (fetal and neonatal), porcine, and human materials.

Looseness in bovine leather: microstructural characterization.

Background: A substantial proportion of bovine leather production may be of poor quality, with the leather suffering from a characteristic known as looseness. This defect results in a poor visual appearance and greatly reduced value. The structural mechanism of looseness is not well understood.

Age dependent differences in collagen alignment of glutaraldehyde fixed bovine pericardium.

Bovine pericardium is used for heart valve leaflet replacement where the strength and thinness are critical properties. Pericardium from neonatal animals (4-7 days old) is advantageously thinner and is considered as an alternative to that from adult animals. Here, the structures of adult and neonatal bovine pericardium tissues fixed with glutaraldehyde are characterized by synchrotron-based small angle X-ray scattering (SAXS) and compared with the mechanical properties of these materials.

Collagen fibril diameter and leather strength.

The main structural component of leather and skin is type I collagen in the form of strong fibrils. Strength is an important property of leather, and the way in which collagen contributes to the strength is not fully understood. Synchrotron-based small angle X-ray scattering (SAXS) is used to measure the collagen fibril diameter of leather from a range of animals, including sheep and cattle, that had a range of tear strengths.

Living with Stress: A Lesson from the Enteric Pathogen Salmonella enterica.

The ability to sense and respond to the environment is essential for the survival of all living organisms. Bacterial pathogens such as Salmonella enterica are of particular interest due to their ability to sense and adapt to the diverse range of conditions they encounter, both in vivo and in environmental reservoirs. During this cycling from host to non-host environments, Salmonella encounter a variety of environmental insults ranging from temperature fluctuations, nutrient availability and changes in osmolarity, to the presence of antimicrobial peptides and reactive oxygen/nitrogen species.