Purpose: To describe the physiology of spinal growth in patients with adolescent idiopathic scoliosis (AIS).
Methods: Narrative review of the literature with a focus on mechanisms of growth.
Results: In his landmark publication On Growth and Form, D'Arcy Thompson wrote that the anatomy of an organism reflects the forces it is subjected to.
Objective: To investigate whether and how a single traumatic impact changes the mechanical properties of talar articular cartilage.
Design: A marble was placed on the joint surface and a weight was dropped on both medial and lateral caprine talus to create a well-defined single focal impact. The mechanical properties of intact and impacted talar cartilage were measured with a micro-indenter.
Injectable implants constitute a newly developed treatment class in the battle against osteoarthritis. They consist of water-formulated supramolecular polymer, coming from a new class of resorbable biomedical materials, and are implanted in encapsulated joints in a liquid form, where they solidify to form a tough, elastic, and cushioning layer between the joint surfaces. To resort any effect, intra-articular delivery should be guaranteed, and the implant should be distributed throughout the entire joint space.
View Article and Find Full Text PDFCurr Osteoporos Rep
April 2022
Purpose Of Review: Osteocytes are the conductors of bone adaptation and remodelling. Buried inside the calcified matrix, they sense mechanical cues and signal osteoclasts in case of low activity, and osteoblasts when stresses are high. How do osteocytes detect mechanical stress? What physical signal do they perceive? Finite element analysis is a useful tool to address these questions as it allows calculating stresses, strains and fluid flow where they cannot be measured.
View Article and Find Full Text PDFSomitogenesis refers to the segmentation of the paraxial mesoderm, a tissue located on the back of the embryo, into regularly spaced and sized pieces, i.e., the somites.
View Article and Find Full Text PDFTo define technical specifications for artificial substitutes, it is necessary to model their mechanical behaviour. Here we studied the linear and nonlinear biphasic models for Nucleus Pulposus (NP) and Annulus Fibrosus (AF). The associated material parameters were obtained using confined compression stress relaxation tests on goat intervertebral disc (IVD) samples.
View Article and Find Full Text PDFMorphogenesis is a continuous process of pattern formation so complex that it requires in vivo monitoring for better understanding. Changes in tissue shape are initiated at the cellular level, where dynamic intracellular F-actin networks determine the shape and motility of cells, influence differentiation and cytokinesis and mediate mechanical signaling. Here, we stain F-actin with the fluorogenic probe SiR-actin for live fluorescence imaging of whole chick embryos.
View Article and Find Full Text PDFOsteons are cylindrical structures of bone created by matrix resorbing osteoclasts, followed by osteoblasts that deposit new bone. Osteons align with the principal loading direction and it is thought that the osteoclasts are directed by osteocytes, the mechanosensitive cells that reside inside the bone matrix. These osteocytes are presumably controlled by interstitial fluid flow, induced by the physiological loading of bones.
View Article and Find Full Text PDFMater Sci Eng C Mater Biol Appl
January 2021
Pelvic organ prolapse (POP) is a multifactorial condition characterized by the descent of the pelvic organs due to the loss of supportive tissue strength. This is presumably caused by the decreased fibroblast function and the subsequent change in the quality of the extracellular matrix. The correction of POP using an implant intends to provide mechanical support to the pelvic organs and to stimulate a moderate host response.
View Article and Find Full Text PDFEmbryos are growing organisms with highly heterogeneous properties in space and time. Understanding the mechanical properties is a crucial prerequisite for the investigation of morphogenesis. During the last 10 years, new techniques have been developed to evaluate the mechanical properties of biological tissues in vivo.
View Article and Find Full Text PDFAdolescent idiopathic scoliosis (AIS) has been linked to neurological, genetic, hormonal, microbial, and environmental cues. Physically, however, AIS is a structural deformation, hence an adequate theory of etiology must provide an explanation for the forces involved. Earlier, we proposed differential growth as a possible mechanism for the slow, three-dimensional deformations observed in AIS.
View Article and Find Full Text PDFThe complex hymenophore configuration of the oak mazegill (, Polyporales) is rarely quantified, although quantifications are important analytical tools to assess form and growth. We quantified the hymenophore configuration of the oak mazegill by manual counting of tubes and tubular branches and ends. Complementary measurements were made with the software AngioTool.
View Article and Find Full Text PDFJ Biomed Mater Res B Appl Biomater
November 2020
The temporomandibular joint disc is a fibrocartilaginous structure, composed of collagen fibers, elastin fibers, and proteoglycans. Despite the crucial role of elastin fibers in load-bearing properties of connective tissues, its contribution in temporomandibular joint disc biomechanics has been disregarded. This study attempts to characterize the structural-functional contribution of elastin in the temporomandibular joint disc.
View Article and Find Full Text PDFSomitogenesis, the primary segmentation of the vertebrate embryo, is associated with oscillating genes that interact with a wave of cell differentiation. The necessity of cell-matrix adherence and embryonic tension, however, suggests that mechanical cues are also involved. To explicitly investigate this, we applied surplus axial strain to live chick embryos.
View Article and Find Full Text PDFObjective: Possible regenerative treatments for lumbar intervertebral disc degeneration (DD) are rapidly emerging. There is consensus that the patient that would benefit most has early-stage DD, with a predicted deterioration in the near future. To identify this patient, the aim of this study was to identify prognostic factors for progression of DD.
View Article and Find Full Text PDFThe temporomandibular joint disc is a structure, characterized as heterogeneous fibrocartilage, and is composed of macromolecular biopolymers. Despite a large body of characterization studies, the contribution of matrix biopolymers on the dynamic viscoelastic behavior of the disc is poorly understood. Given the high permeability and low concentration of glycosaminoglycans in the disc, it has been suggested that poro-elastic behavior can be neglected and that the intrinsic viscoelastic nature of solid matrix plays a dominant role in governing its time-dependent behavior.
View Article and Find Full Text PDFIntervertebral disc degeneration describes the vicious cycle of the deterioration of intervertebral discs and can eventually result in degenerative disc disease (DDD), which is accompanied by low-back pain, the musculoskeletal disorder with the largest socioeconomic impact world-wide. In more severe stages, intervertebral disc degeneration is accompanied by loss of joint space, subchondral sclerosis, and osteophytes, similar to osteoarthritis (OA) in the articular joint. Inspired by this resemblance, we investigated the analogy between human intervertebral discs and articular joints.
View Article and Find Full Text PDFThe investigation of the mechanical properties of embryos is expected to provide valuable information on the phenomenology of morphogenesis. It is thus believed that, by mapping the viscoelastic features of an embryo at different stages of growth, it may be possible to shed light on the role of mechanics in embryonic development. To contribute to this field, we present a new instrument that can determine spatiotemporal distributions of mechanical properties of embryos over a wide area and with unprecedented accuracy.
View Article and Find Full Text PDFThe extracellular matrix of fascia-like tissues is a resilient network of collagenous fibers that withstand the forces of daily life. When overstretched, the matrix may tear, with serious consequences like pelvic organ prolapse (POP). Synthetic implants can provide mechanical support and evoke a host response that induces new matrix production, thus reinforcing the fascia.
View Article and Find Full Text PDFJ Cardiovasc Dev Dis
September 2018
That form and function are related is a maxim of anatomy and physiology. Yet, form-function relations can be difficult to prove. Human subjects with excessive trabeculated myocardium in the left ventricle, for example, are diagnosed with non-compaction cardiomyopathy, but the extent of trabeculations may be without relation to ejection fraction.
View Article and Find Full Text PDFBiochem Biophys Res Commun
September 2018
The mammalian intervertebral disc (IVD) consists of a gel-like, disordered nucleus pulposus (NP) surrounded by a highly ordered collagen structure, the annulus fibrosus (AF). While this concentric array of lamellae has been amply studied, its physical origin is poorly understood. The notochord is a rod-like organ located in the mid-line of the growing embryo and plays an essential role in IVD development.
View Article and Find Full Text PDFIntervertebral disk (IVD) degeneration is commonly described by loss of height and hydration. However, in the first stage of IVD degeneration, this loss has not yet occurred. In the current study, we use an ex vivo degeneration model to analyze the changes in IVDs mechanical behavior in the first phase of degeneration.
View Article and Find Full Text PDFA correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
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