Biocompatibility and tissue regenerating capacity of crosslinked dermal sheep collagen

The biocompatibility and tissue regenerating capacity of four crosslinked dermal sheep collagens (DSC) was studied. In vitro, the four DSC versions were found to be noncytotoxic or very low in cytoxicity. After subcutaneous implantation in rats, hexamethylenediisocyanatecrcrosslinked DSC (HDSC) seldom induced an increased infiltration of neutrophils or macrophages, as compared with normal wound healing; whereas new formation of collagen was observed. DSC crosslinked with glutaraldehyde (GDSC) followed by reaction with NaBH4 shortly after implantation showed an increased infiltration of neutrophils with a deviant morphology. Furthermore, a high incidence of calcification was observed, which may explain the minor ingrowth of giant cells and fibroblasts, and the poor formation of new rat collagen. Acyl azide-crosslinked DSC (AaDSC) first induced an increased infiltration of macrophages, and then of giant cells, both with high lipid formation. AaDSC degraded at least twice as slowly as HDSC and GDSC, finally leaving a matrix of newly formed rat collagen. Samples crosslinked with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide (ENDSC) induced the same mild cellular reaction as HDSC; whereas, similar to AaDSC, the degradation rate was slow and an optimal rat collagen matrix was formed. Of the crosslinked DSC samples, ENDSC seems most promising for tissue regeneration

Treading air

In 1920s Queensland, Lizzie O'Dea wants to get away from her dad and the memories of her mum that haunt her. At the races she meets attractive, war-scarred Joe and sees her chance to escape. But life with Joe isn't what she dreamt it would be. Finding herself on the fringes of society, Lizzie discovers a new sense of independence and sexuality, love and friendship. It's a precarious life, though, always on the edge of collapse. Two decades later, Lizzie is sick and worn out. Lying in a Brisbane lock hospital, she thinks about Joe, who's been lost to her for many years. But she's a survivor. There's hope yet. Set between Brisbane and Townsville, and based on real events that the author uncovered from historical archives, Treading Air is the remarkably vivid tale of a young Australian working-class rebel who clashed with the expectations of her world

Calcification of subcutaneously implanted collagens in relation to cytotoxicity, cellular interactions and crosslinking

In general, calcification of biomaterials occurs through an interaction of host and implanted material factors, but up to now the real origin of pathologic calcification is unknown. In this study we aimed to investigate incidence of calcification of (crosslinked) dermal sheep collagens (DSCs) with respect to their specific properties, during subcutaneous implantation in rats. Three types of DSCs were commercially obtained: non-crosslinked DSC (NDSC), and DSC crosslinked with glutaraldehyde (GDSC) and hexamethylenediisocyanate (HDSC). NDSC, HDSC and GDSC were (enzymatically) tissue culture pretreated to eliminate their cytotoxic products. Beside this, crosslinking methods were modified to optimize mechanical properties and to decrease cytotoxicity, which resulted in HDSC* and GDSC*. Furthermore, DSC was crosslinked by activation of the carboxylic groups, i.e. by means of acyl azide and carbodiimide, resulting in AaDSC and CDSC, respectively. After implantation of HDSCs and GDSCs a relation between cytotoxicity and calcification of crosslinked DSC could be made. No relation was found between cellular infiltration of DSCs and calcification. However, from the use of different types and modification of crosslinking methods it might be concluded that calcification is mainly related to stable crosslinks, i.e. to the chemical properties of the obtained material

Sharing Qualitative Research: showing lived experience and community narratives

In an era of rapid technological change, are qualitative researchers taking advantage of new and innovative ways to gather, analyse and share community narratives? Sharing Qualitative Research presents innovative methods for harnessing creative storytelling methodologies and technologies that help to inspire and transform readers and future research. In exploring a range of collaborative and original social research approaches to addressing social problems, this text grapples with the difficulties of working with communities. It also offers strategies for working ethically with narratives, while also challenging traditional, narrower definitions of what constitutes communities. The book is unique in its cross-disciplinary spectrum, community narratives focus and showcase of arts-based and emerging digital technologies for working with communities. A timely collection, it will be of interest to interdisciplinary researchers, undergraduate and postgraduate students and practitioners in fields including anthropology, ethnography, cultural studies, community arts, literary studies, social work, health and education

Changes in the mechanical properties of dermal sheep collagen during in vitro degradation

The changes in tensile strength, elongation at break, and high strain modulus of dermal sheep collagen (DSC) during in vitro degradation using bacterial collagenase were studied. The changes in mechanical properties were compared with the change in weight of the samples as a function of degradation time. DSC was crosslinked with either glutaraldehyde (GA) or hexamethylene diisocyanate (HMDIC). During degradation, the changes in mechanical properties of the N-DSC, H-DSC or G-DSC samples were more pronounced than the changes in the weight of the samples. Of the mechanical properties studied, the tensile strength was most susceptible to degradation of the DSC samples. After 2.5 h, N-DSC samples had lost only 55% of their initial weight, but the samples had no tensile strength left. Similar results were obtained for H-DSC, which retained no tensile strength after 24 h degradation, whereas only 45% of the initial weight was lost. G-DSC lost 3.5% of its weight after 24 h degradation, but only 25% of the initial tensile strength remained

Sharing Qualitative Research: showing lived experience and community narratives

In an era of rapid technological change, are qualitative researchers taking advantage of new and innovative ways to gather, analyse and share community narratives? Sharing Qualitative Research presents innovative methods for harnessing creative storytelling methodologies and technologies that help to inspire and transform readers and future research. In exploring a range of collaborative and original social research approaches to addressing social problems, this text grapples with the difficulties of working with communities. It also offers strategies for working ethically with narratives, while also challenging traditional, narrower definitions of what constitutes communities. The book is unique in its cross-disciplinary spectrum, community narratives focus and showcase of arts-based and emerging digital technologies for working with communities. A timely collection, it will be of interest to interdisciplinary researchers, undergraduate and postgraduate students and practitioners in fields including anthropology, ethnography, cultural studies, community arts, literary studies, social work, health and education

Cross-linking of dermal sheep collagen using a water-soluble carbodiimide

A cross-linking method for collagen-based biomaterials was developed using the water-soluble carbodiimide 1-ethyl-3-(3-dimethyl aminopropyl)carbodiimide hydrochloride (EDC). Cross-linking using EDC involves the activation of carboxylic acid groups to give O-acylisourea groups, which form cross-links after reaction with free amine groups. Treatment of dermal sheep collagen (DSC) with EDC (E-DSC) resulted in materials with an increased shrinkage temperature (Ts) and a decreased free amine group content, showing that cross-linking occurred. Addition of N-hydroxysuccinimide to the EDC-containing cross-linking solution (E/N-DSC) increased the rate of cross-linking. Cross-linking increased the Ts of non-cross-linked DSC samples from 56 to 73 °C for E-DSC and to 86 °C for E/N-DSC samples, respectively. For both cross-linking methods a linear relation between the decrease in free amine group content and the increase in Ts was observed. The tensile strength and the high strain modulus of E/N-DSC samples decreased upon cross-linking from 18 to 15MPa and from 26 to 16MPa, respectively. The elongation at break of E/N-DSC increased upon cross-linking from 142 to 180%