Composition, structure and tensile biomechanical properties of equine articular cartilage during growth and maturation.

Articular cartilage undergoes structural and biochemical changes during maturation, but the knowledge on how these changes relate to articular cartilage function at different stages of maturation is lacking. Equine articular cartilage samples of four different maturation levels (newborn, 5-month-old, 11-month-old and adult) were collected (N = 25). Biomechanical tensile testing, Fourier transform infrared microspectroscopy (FTIR-MS) and polarized light microscopy were used to study the tensile, biochemical and structural properties of articular cartilage, respectively.

Accuracy and reliability of a hand-held in vivo skin indentation device to assess skin elasticity.

Objective: The aim of this study was to evaluate the performance of a hand-held indentation device for fast and reliable determination of skin stiffness.

Methods: Device accuracy to indentation depths of 0.6 and 1.

In Vivo Contrast-Enhanced Cone Beam CT Provides Quantitative Information on Articular Cartilage and Subchondral Bone.

In post-traumatic osteoarthritis, both articular cartilage and subchondral bone undergo characteristic pathological changes. This study investigates potential of delayed cone beam computed tomography arthrography (dCBCTa) to simultaneously detect variations in cartilage and subchondral bone. The knees of patients (n = 17) with suspected joint injuries were imaged using a clinical CBCT scanner at 5 and 45 min after the intra-articular injection of anionic contrast agent (Hexabrix™) with hydroxyapatite phantoms around the knee.

Modeling of interstitial fluid movement in soft tissue under negative pressure--relevance to treatment of tissue swelling.

Exact physiological mechanisms behind the potential positive treatment effects of pathological tissue swelling (edema), such as increased interstitial fluid flow, are poorly understood. Finite-element model was created and the model response was matched with the deformation data from the negative pressure (suction) measurements in human (N = 11) forearm. Two experimental suction protocols were simulated to evaluate their impact on interstitial fluid flow in soft tissues.

Short-term exercise-induced improvements in bone properties are for the most part not maintained during aging in hamsters.

Physical exercise during growth affects composition, structure and mechanical properties of bone. In this study we investigated whether the beneficial effects of exercise during the early growth phase have long-lasting effects or not. Female Syrian golden hamsters (total n=152) were used in this study.

Experimental and numerical analysis of soft tissue stiffness measurement using manual indentation device--significance of indentation geometry and soft tissue thickness.

Background: Indentation techniques haves been applied to measure stiffness of human soft tissues. Tissue properties and geometry of the indentation instrument control the measured response.

Methods: Mechanical roles of different soft tissues were characterized to understand the performance of the indentation instrument.

Experimental and computational analysis of soft tissue mechanical response under negative pressure in forearm.

Background: Instrumentation, relying on the use of negative pressure (suction), has been introduced to reduce pathological tissue swelling. Then, relative contribution of skin, adipose tissue and muscle, to the overall mechanical response is not known.

Methods: Under suction, stretch of soft tissues in the forearm of human subjects (N = 11) was experimentally measured at rest and under venous occlusion.

Experimental and computational analysis of soft tissue stiffness in forearm using a manual indentation device.

A hand held stiffness meter can be used to measure indentation stiffness of human soft tissues, sensitively altered, e.g., by pathological tissue swelling.

Effects of growth and exercise on composition, structural maturation and appearance of osteoarthritis in articular cartilage of hamsters.

Articular cartilage composition and structure are maintained and remodeled by chondrocytes under the influence of loading. Exercise-induced changes in the composition, structure, mechanical properties and tissue integrity of growing and aging hamster articular cartilage were investigated. Articular cartilage samples (n = 191) were harvested from the proximal tibiae of hamsters aged 1, 3, 6, 12 and 15 months.

Collagen and mineral deposition in rabbit cortical bone during maturation and growth: effects on tissue properties.

We characterized the composition and mechanical properties of cortical bone during maturation and growth and in adult life in the rabbit. We hypothesized that the collagen network develops earlier than the mineralized matrix. Growth was monitored, and the rabbits were euthanized at birth (newborn), and at 1, 3, 6, 9, and 18 months of age.

Maturation of collagen fibril network structure in tibial and femoral cartilage of rabbits.

Objective: The structure and composition of articular cartilage change during development and growth, as well as in response to varying loading conditions. These changes modulate the functional properties of cartilage. We studied maturation-related changes in the collagen network organization of cartilage as a function of tissue depth.

Long-term voluntary exercise of male mice induces more beneficial effects on cancellous and cortical bone than on the collagenous matrix.

The effects of lifelong physical exercise on the composition, structure and mechanical properties of bone are not well understood. Earlier, we found that voluntary physical exercise improved various properties of bone in maturing male mice up to 6 months of age. In this study, we extended the previous study to 18 months.

Physical exercise improves properties of bone and its collagen network in growing and maturing mice.

This study characterized bone structure, composition, and mechanical properties in growing male mice. The development of the collagen network during maturation was monitored, and the effect of voluntary physical exercise was investigated. We hypothesized that increased bone loading from exercise would increase the amount and improve the properties of the collagen network during growth and maturation.

Biomechanical, biochemical and structural correlations in immature and mature rabbit articular cartilage.

Objective: The structure and composition of articular cartilage change during development and growth. These changes lead to alterations in the mechanical properties of cartilage. In the present study, biomechanical, biochemical and structural relationships of articular cartilage during growth and maturation of rabbits are investigated.

Fluid pressure driven fibril reinforcement in creep and relaxation tests of articular cartilage.

Biological tissues exhibit diverse mechanical behaviors because of complex material properties. As has been shown for ligaments and intervertebral discs, mathematical models often appear to well predict load responses individually by adjusting model parameters, but likely fail to describe several different load responses simultaneously using the same model parameters. In the present study, we attempted to describe and explain both creep and relaxation responses of articular cartilage using a fibril-reinforced model, which has been successfully used to account for the load response of the relaxation tests of articular cartilage.

The Evolving Tree--analysis and applications.

In this paper, we enhance and analyze the Evolving Tree (ETree) data analysis algorithm. The suggested improvements aim to make the system perform better while still maintaining the simple nature of the basic algorithm. We also examine the system's behavior with many different kinds of tests, measurements and visualizations.