Dependence of Intervertebral Disc Pressure Generation on Load History

Author(s):  
David Hwang ◽  
Miao Yu ◽  
Adam H. Hsieh

It has been thoroughly documented that low back pain is often associated with deregulated biological function and compromised mechanical behavior of the intervertebral disc. Therefore, intervertebral disc mechanics have long been thought of as important factors both in driving cell-mediated processes involved in degeneration and in distinguishing between healthy versus degenerate discs. The nucleus pulposus is an integral part of the mechanics of the disc, the key property being its ability to pressurize to resist and distribute compressive stress to the annulus fibrosus and the endplates. There has been a history of intradiscal pressure measurements in cadaveric as well as large animal studies; however, these studies have focused on the consequences of degeneration or the change in stress distribution by varying spinal orientations. In order to be able to relate local stresses induced in discs to changes in cellular function, such pressure measurements must be obtained from an animal model amenable to chronic disc loading. Rat tail discs have been one widely used laboratory model, but the discs are too small for measuring load-induced nucleus pressures using current sensor technology.

JOR Spine ◽  
2021 ◽  
Author(s):  
Naomi N. Lee ◽  
Elias Salzer ◽  
Frances C. Bach ◽  
Andres F. Bonilla ◽  
James L. Cook ◽  
...  

2021 ◽  
Vol 22 (11) ◽  
pp. 5648
Author(s):  
Takashi Yurube ◽  
Hiroaki Hirata ◽  
Masaaki Ito ◽  
Yoshiki Terashima ◽  
Yuji Kakiuchi ◽  
...  

The intervertebral disc is the largest avascular low-nutrient organ in the body. Thus, resident cells may utilize autophagy, a stress-response survival mechanism, by self-digesting and recycling damaged components. Our objective was to elucidate the involvement of autophagy in rat experimental disc degeneration. In vitro, the comparison between human and rat disc nucleus pulposus (NP) and annulus fibrosus (AF) cells found increased autophagic flux under serum deprivation rather in humans than in rats and in NP cells than in AF cells of rats (n = 6). In vivo, time-course Western blotting showed more distinct basal autophagy in rat tail disc NP tissues than in AF tissues; however, both decreased under sustained static compression (n = 24). Then, immunohistochemistry displayed abundant autophagy-related protein expression in large vacuolated disc NP notochordal cells of sham rats. Under temporary static compression (n = 18), multi-color immunofluorescence further identified rapidly decreased brachyury-positive notochordal cells with robust expression of autophagic microtubule-associated protein 1 light chain 3 (LC3) and transiently increased brachyury-negative non-notochordal cells with weaker LC3 expression. Notably, terminal deoxynucleotidyl transferase dUTP nick end labeling-positive apoptotic death was predominant in brachyury-negative non-notochordal cells. Based on the observed notochordal cell autophagy impairment and non-notochordal cell apoptosis induction under unphysiological mechanical loading, further investigation is warranted to clarify possible autophagy-induced protection against notochordal cell disappearance, the earliest sign of disc degeneration, through limiting apoptosis.


2017 ◽  
Vol 21 (2) ◽  
pp. 138-141 ◽  
Author(s):  
Toshihide Mizuno ◽  
Tomonori Tsukiya ◽  
Yoshiaki Takewa ◽  
Eisuke Tatsumi

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2077
Author(s):  
Oliver Zeman ◽  
Michael Schwenn ◽  
Martin Granig ◽  
Konrad Bergmeister

The assessment of already installed anchorages for a possible exceeding of the service load level is a question that is gaining more and more importance, especially in building maintenance. Bonded anchors are of particular interest here, as the detection of a capacity reduction or load exceedance can cause damage to the concrete-bonded mortar behavior. This article investigates the extent to which ultrasonic methods can be used to make a prediction about the condition of anchorages in concrete and about their load history. A promising innovative assessment method has been developed. The challenges in carrying out the experimental investigations are the arrangement of the transducers, the design of the test set-up and the applicability of direct, indirect or semidirect ultrasonic transmission. The experimental investigations carried out on a test concrete mix and a bonded anchor system show that damage to the concrete structure can be detected by means of ultrasound. The results indicate the formation of cracks and therefore a weakening of the response determined by means of direct, indirect and semidirect ultrasonic transmission. However, for application under non-laboratory conditions and on anchors with unknown load history, the calibration with a reference anchor and the identification of the maximum load is required. This enables a referencing of the other loaded anchors to the unloaded conditions and allows an estimation of the load history of individual anchors.


2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Selen Uman ◽  
Jason A Burdick

Introduction: Early studies have shown therapeutic benefits of mesenchymal stromal cells (MSCs) in cardioprotection due to their angiogenic, proliferative, anti-apoptotic and anti-inflammatory properties, which are now attributed to secreted factors such as extracellular vesicles (EVs). While MSC-EVs have shown promise in small animals for cardiovascular therapies, large animal studies are required to evaluate the therapeutic benefit of MSC-EVs for clinical translation. One of the biggest challenges for large animal studies is the need to generate clinically-relevant quality and quantity of EVs without batch-to-batch variations that could compromise efficacy. This study aims to explore three different cell culture methods (traditionally-used tissue culture plates (TCP), 3-D printed bioscaffolds in a perfusion system (P), and microcarriers in dynamic spinner flask conditions (M)) to scale-up the production of MSC-EVs across four different biological donors and rigorously investigate EV yield, size, shape, and content. Methods: MSCs were isolated from the iliac crest of four different Yucatan minipigs using heparinized syringes, and cells were expanded to passage four, at which point they were seeded onto the respective cell culture methods. EVs were collected from conditioned medium (CM) via differential ultracentrifugation. EV size, distribution, yield, and protein concentration were studied using Nanoparticle Tracking Analysis (NTA) and microBCA assays. Results: Both perfusion bioreactor and spinner flask systems enabled sustained maintenance of large numbers of cells. Across biological donors and fabrication methods, modes remained within 50-150 nm and were not statistically different. Microcarrier-based spinner flasks and perfusion bioreactor set-ups both improved EV yield, up to 6 times in efficiency. Ongoing research focuses on examining differences in EV content across biological donors using RNA-sequencing and proteomics.


2005 ◽  
Vol 99 (4) ◽  
pp. 1582-1591 ◽  
Author(s):  
Donna R. Hill ◽  
Marianne E. Brunner ◽  
Deborah C. Schmitz ◽  
Catherine C. Davis ◽  
Janine A. Flood ◽  
...  

Previous in vitro and in vivo animal studies showed that O2and CO2concentrations can affect virulence of pathogenic bacteria such as Staphylococcus aureus. The objective of this work was to measure O2and CO2levels in the vaginal environment during tampon wear using newly available sensor technology. Measurements by two vaginal sensors showed a decrease in vaginal O2levels after tampon insertion. These decreases were independent of the type of tampons used and the time of measurement (mid-cycle or during menstruation). These results are not in agreement with a previous study that concluded that oxygenation of the vaginal environment during tampon use occurred via delivery of a bolus of O2during the insertion process. Our measurements of gas levels in menses showed the presence of both O2and CO2in menses. The tampons inserted into the vagina contained O2and CO2levels consistent with atmospheric conditions. Over time during tampon use, levels of O2in the tampon decreased and levels of CO2increased. Tampon absorbent capacity, menses loading, and wear time influenced the kinetics of these changes. Colonization with S. aureus had no effect on the gas profiles during menstruation. Taken collectively, these findings have important implications on the current understanding of gaseous changes in the vaginal environment during menstruation and the potential role(s) they may play in affecting bacterial virulence factor production.


2021 ◽  
Author(s):  
◽  
Janine Ruth Cook

<p>Within the New Zealand poultry industry press between 1900 and 1960, scientific approaches were promoted and ‘sentimentality’ discouraged, yet comparative and anthropomorphic description suggesting similarities between chickens and humans persisted. Feathered Friends and Human Animals explores this phenomenon within poultry journals, newspapers, advice books and official publications. Four key themes of comparison are identified: ideas about the chicken mind, the chicken-as-worker, poultry ‘eugenics’, and health and hygiene.  It is argued that humanitarian, theological, and philosophical ideas, the ‘natural’ empathetic and humoured identification that arises through everyday contact with animals within relatively small systems, and the rationalisation of industry, were all significant factors contributing to sustained comparison. However, the public articulation of fundamental biological ideas – encapsulated in the modern, overarching concept of ‘general biology’ – validated and integrated these discourses.  General biology influenced new trends in education and in the popular and public articulation of research into the life sciences of this period. It encouraged the integration of sympathetic naturalist persepectives, including evolutionary based ideas about ‘natural laws’, with emerging new science that continued to establish many fundamental biological principles through extrapolation from experimental animals to human animals. This study demonstrates that poultry experts’ attended to this same blend of older naturalist science and new scientific knowledge.  Historians’ focus on emerging specialist science in the early twentieth century has tended to obfuscate the realities of science education within the applied sciences and amongst lay audiences, and the continued interest in fundamental aspects of biology within professional science. The findings of this study reveal that farming ideas did not develop within a bubble, determined only by animal husbandry traditions and industry-specific applied research. They also suggest that practitioners’ conceptions of biology within applied fields of this era were not as distinct as has been supposed.  As a ‘bottom-up’ cultural history of science, this study illustrates the articulation of general biology within an agricultural context. This is the key contribution offered to local and international historiography. However, other elements of the study expand existing scholarship. In exploring ideas about race and eugenics, it offers a broader framework for social historians, who, while cognisant of the eugenic mind-set of this period, have granted little attention to general biology as a professional trend. It offers insight into the agendas and tensions within school nature study and elementary science. It is also the first comprehensive history of the New Zealand poultry industry. Poultry-keeping engaged up to around 60 percent of the nation’s households in this period, including thousands of farmers who kept sideline flocks, but as a predominantly domestic (as opposed to export) industry it has been overlooked by social and agricultural historians.  The field of human animal studies, which has tended to gloss over both this era of transition prior to modern agribusiness and scientific discourses, is also advanced by this study, and this is the first New Zealand agricultural history to engage with this field and examine animal husbandry ideologically. It reveals how fundamental science knowledge, entwined with moral perspectives, continued to shape ideas about animals’ needs and behaviour well beyond the Victorian period. Assumptions of similarity however, were not always beneficial for the animal, and human-bird comparison was used to both justify and deny kind treatment.</p>


Author(s):  
Kara Stone

What can post-humanism teach us about game design? This paper questions the line drawn between what species and matter can play and what cannot play. Combining works by scholars of feminist post-humanism, new materialism, and game studies, primarily Jane Bennett, Donna Haraway, and T.L. Taylor, it proposes that play is a form of communication not only between animals and humans but also between plants and cyborgs, insects and atoms. Beginning by interrogating the borders of the human that have been built on ableist and racist discourses, this paper moves towards considering the human as interspecies and outlines that we must reassess the ways in which a multiplicity of species experience the intra-action that constitutes “play.” With a brief look into the history of defining play in both game studies and animal studies and their small crossover, play is reconfigured into an outlook or an approach rather than a set of rules. It is a drive that all species and matter experience, including insects, bacteria, and metal. This moves us beyond considering solely the materiality of our bodies at play by reconsidering the objects of play as our co-players, as matter with agential force. I argue that we need to reconsider the videogame player as an interspecies being, an assemblage of human and non-human bodies. The de-anthropocentricization of the popular notions of player agency allows for a multiplicity of reactions not created in the linear cause and effect course, the belief in ultimate player control within procedural systems, which dominates game studies. This paper concludes by submitting possibilities of what considering the non-human through a feminist and anti-ableist lens can offer game designers, players, and critics, such as considering the material platform’s impact on play, reforming the individualistic agency of players, and designing for the Other(s).


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