No description available.

No description available.

No description available.

Yes / The level of glutamine (Gln) deamidation in bone collagen provides information on the diagenetic history of bone but, in order to accurately assess the extent of Gln deamidation, it is important to minimise the conditions that may induce deamidation during the sample preparation. Here we report the results of a preliminary investigation of the variability in glutamine deamidation levels in an archaeological bone due to: a) sampling location within a bone; b) localised diagenesis; and c) sample preparation methods. We then investigate the effects of pre-treatment on three bone samples: one modern, one Medieval and one Pleistocene. The treatment of bone with acidic solutions was found to both induce deamidation and break down the collagen fibril structure. This is particularly evident in the Pleistocene material (~80,000 years BP) considered in this study. We show that ethylenediaminetetraacetic acid (EDTA), when used as an alternative to hydrochloric acid (HCl) demineralisation, induces minimal levels of deamidation and maintains the collagen fibril structure. Areas of bone exhibiting localised degradation are shown to be correlated with an increase in the levels of Gln deamidation. This indicates that the extent of Gln deamidation could provide a marker for diagenesis but that sampling is important, and that, whenever possible, subsamples should be taken from areas of the bone that are visually representative of the bone as a whole. Although validation of our observations will require analysis of a larger sample set, deamidation measurements could be a valuable screening tool to evaluate the suitability of bone for further destructive collagen analyses such as isotopic or DNA analysis, as well as assessing the overall preservation of bone material at a site. The measure of bone preservation may be useful to help conservators identify bones that may require special long-term storage conditions. / NERC (NE/J500197/1), Yorkshire Forward - Northern Way Initiative, Science City York, Gordon and Betty Moore Foundation, Leverhulme Trust

No / Streptococcus mutans was shown to produce two extracellular proteases capable of degrading both gelatin and collagen-like substrates. These enzymes have molecular masses of 52 and 50 kDa when analysed by SDS-PAGE. Both enzymes were inhibited by EDTA, but not by a range of other inhibitors with different specificities, indicating that they are metalloproteases. The activity of EDTA-inactivated enzymes could be restored by the addition of manganese and zinc. The identical inhibition and restoration profiles of the two enzymes suggest that one of the proteases may be a degradation product of the other.

Teotihuacan, Mexico, is an example of an early city that supported a substantial population in the absence of large, domesticated animals. This dissertation examines the diverse animal acquisition strategies employed by Teotihuacan’s inhabitants as part of the urban subsistence economy during its apogee (c. 200-550 CE). It integrates zooarchaeological methodologies with proteomic and isotopic techniques to analyze faunal material recovered from Tlajinga and Tlailotlacan, two neighborhoods on the urban periphery. The study has three components. The first component employs Zooarchaeology by Mass Spectrometry (ZooMS) to examine the archaeological remains of birds at Tlajinga. It presents the first major set of avian collagen peptide biomarkers and demonstrates the utility of ZooMS for identifying birds to family and sub-family levels. This technique provides the means to categorize archaeological bird remains, which demonstrates that the residents of Tlajinga had access to a diversity of aquatic birds, illustrating lake exploitation in Teotihuacan’s urban subsistence. The second component analyzes excavated animal remains in two adjacent apartment compounds in the Tlajinga district to understand urban subsistence. It documents how animal consumption varies over space, while controlling for factors that affect taxonomic composition, such as depositional context, excavation strategies, wealth, and cultural affiliations. It appears that the variability found among different faunal assemblages at Teotihuacan may be due to local hunting practices and the choice of which activity areas of the residential compounds were excavated, rather than wealth differences among households. The third component examines the role of animals in the urban economy of Tlailotlacan and Tlajinga using new isotopic data from turkeys, deer, rabbits, and hares. The residents of these two neighborhoods employed diversified strategies to acquire wild animals for urban consumption from multiple natural and anthropogenic niches around the city. Hunting and trapping wild animals was supplemented with lake resources from the extensive lacustrine system in the Basin of Mexico, and small-scale turkey husbandry. Overall, Teotihuacan’s animal economy is relevant to understanding diversity in global urban subsistence systems; it reflects a diversified system of animal production at the household level, distinct from the specialized, and often institutionalized, large-animal economies that supported preindustrial Afro-Eurasian cities. / 2024-10-03T00:00:00Z

<div>Vocal fold scarring is the fibrotic manifestation of most common pathological voice disorders. Voice disorders lead to direct healthcare costs of over $200 million annually and significantly reduce quality of life for patients. Despite advances in understanding the pathophysiology of vocal fold scarring, effective treatments for scarring and fibrosis remain elusive. The wound-healing cascade associated with vocal fold injury involves complex signaling interactions between cells and their extracellular matrix (ECM), which remain largely unexplored due to the lack of a physiologically relevant preclinical model to study them. Traditional preclinical models do not capture the complex 3D microenvironment of the vocal folds, and the use of stem cells or fibroblasts alone in models has resulted in poor reproducibility and predictability of in vitro models. Toward this end, this work describes the development of a preclinical model that strives to take into account cellular interactions between fibroblasts and epithelial cells and achieve a balance in the native vocal fold 3D environment to function as an in vitro model.</div><div><br></div><div>Since a major shortcoming of current in vitro models is the lack of a standardized epithelial fibroblast coculture, initial work focused on developing a coculture system between commercially available tracheal epithelial cells and vocal fold fibroblasts in an in vitro setting that would provide more accurate information about the disease pathophysiology and help design better targeted treatments. We designed a healthy and disease state coculture model that can be induced into a fibroplastic state to overexpress stress fibers using TGFβ1. We also demonstrated that both cell types maintained phenotype in the healthy and disease state coculture models.</div><div><br></div><div>To further transfer this model in a physiologically relevant 3D system, follow-up research characterized 3D matrices to mimic the native ECM of the vocal folds by using natural biomimetic materials found in the vocal folds such as hyaluronic acid, type I collagen, and type III collagen. We hypothesized that the ability to control the viscoelastic and structuralcharacteristics of the scaffold in combination with presenting relevant biological cues to cells will result in a better biomimetic scaffold. This research is expected to lay effective groundwork for developing a functional tissue engineered 3D coculture model that retains the reproducibility necessary to serve as a viable diagnostic and therapeutic screening platform.</div>

Due to its relative avascularity, low cellularity and lack of an undifferentiated cell reservoir, articular cartilage has a limited capacity for self-repair when damaged through trauma or disease. Articular cartilage impairment and the resultant reduced joint function affects millions of people at a substantial cost. In the U.S. alone, over 20 million adults are afflicted with osteoarthritis, costing more than $65 billion per year in health care and lost wages. Surgical techniques have been developed to address small, focal lesions, but more critical sized defects remain without a viable solution. Tissue engineering strategies produce cartilage-like constructs in vitro containing living cells in the hope of replacing damaged cartilage and restoring joint function. However, these constructs lack both sufficient integration into the surrounding tissue following implantation and the mechanical properties capable of withstanding the demanding and complex in vivo loading environment. Our central hypothesis is that exposure of engineered cartilage to fluid-induced shear stress increases the collagen content and mechanical properties (tensile and compressive). The overall objective of this project is to modulate the matrix composition and mechanical properties of engineered cartilage to be more like native tissue using a novel bioreactor. Improving the matrix components and mechanical stability of the tissue to be more similar to that of native tissue may aid in integration into a defect in vivo. The central hypothesis was proven in that shear stress potently altered the matrix composition, gene expression and mechanical properties of both thick and thin engineered cartilage. Modulation was found to be highly dependent on shear stress magnitude, duration, and waveform and affected different matrix constituents and mechanical properties in disparate ways. Our overall objective was satisfied on the basis that the bioreactor created stronger engineered tissues, but with the caveat that the tissues showed an increase in presence of type I collagen. Such an effect would be undesirable for articular cartilage engineered tissues, but could be very beneficial in fibrocartilaginous tissues such as that found in the temporomandibular joint. In conclusion, the novel bioreactor system provides a flexible platform technology for the study of three-dimensional engineered tissues, not just articular cartilage.

Strip steaks from the McGregor genome project were used to evaluate the effects of sarcomere length, myofibrillar fragmentation index, 3 h postmortem pH, 24 h postmortem pH, marbling, electrical stimulation (ES), sarcoplasmic free calcium concentration, and collagen characteristics on tenderness as measured by Warner-Bratzler shear force (WBS). The WBS values were measured prior to this project so the animals were able to be separated into “tender” and “tough” groups using a WBS value of 30 N as the separating point, steaks with a WBS value less than 30 N being “tender” and the others being “tough”. It was found that ES sides had lower WBS values, however, “tough” steaks showed a greater response to ES than “tender” steaks. ES sides also had higher sarcoplasmic free calcium concentration and lower 3 h postmortem pH. Tenderness is best predicted by treatment (ES versus NON-ES), however, there is some efficacy in using total collagen and collagen solubility in conjunction with treatment.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 4 uppsatser.