Post-Acute COVID-19 syndrome (PACS) is considered to be one of the least understood post-infectious syndromes. We report a case of a 21-year-old female who had a history of SARS-CoV-2 infection and presented w… Read More
Month: October 2022
The efficacy of azithromycin to prevent exacerbation of non-cystic fibrosis bronchiectasis: a meta-analysis of randomized controlled studies
The efficacy of azithromycin to prevent exacerbation for non-cystic fibrosis bronchiectasis remains controversial. We conduct this meta-analysis to explore the influence of azithromycin versus placebo for the … Read More
Video-assisted thoracoscopic segmentectomy with combined chest wall resection: A case report
Resection of lung cancer with chest wall involvement is an invasive procedure.
Reversal flow in the left anterior descending artery after internal thoracic artery grafting
The flow capacity of the in situ internal thoracic artery (ITA) is not necessarily sufficient and can be a cause of hypoperfusion syndrome. We present a catastrophic case of in situ ITA grafting for an isolate… Read More
Distal aortic replacement followed by endovascular repair for the management of severe intra-pleural adhesions accidentally detected during open surgery for chronic type B aortic dissection: a report of two cases
Open repair is the most promising curative treatment option for patients with chronic type B aortic dissection. However, based on our experience, following the accidental detection of intra-pleural adhesions d… Read More
Minimising chemical crosslinking for stabilising collagen in acellular bovine pericardium: Mechanistic insights via structural characterisations
Acta Biomater. 2022 Oct 15;152:113-123. doi: 10.1016/j.actbio.2022.08.057. Epub 2022 Aug 30.
ABSTRACT
Chemically crosslinked acellular bovine pericardium (ABP) has been widely used in clinical practice as bioprostheses. To ensure its consistency and durability, crosslinkers are used in excess, with stability guided by indicators including the hydrothermal denaturation temperature, the enzymatic resistance and the degree of crosslinking. Yet, understanding of the intermolecular structure in collagen fibrils which imparts the intrinsic stability of the ABPs is lacking, and the discrepancies in the stability criteria in varied conditions are poorly explained. In this study, synchrotron small-angle X-ray scattering (SAXS) in combination with thermal and colorimetric methods are employed to investigate the changes in the structure and the stability of ABPs during crosslinking using glutaraldehyde (GA) or 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) at different concentrations. Based on the findings, a mechanism is proposed to explicate the crosslinking effects on collagen structure and the relationship between the structure and each stability indicator. At low crosslinker concentrations, the telopeptidyl-helical linkages are preferred, which cause rearrangements in the intermolecular structure of collagen, and efficiently contribute to its stabilities. Excess crosslinking is revealed by a revert trend in structural changes and the plateauing of the stabilities, assigning to the helical-helical linkages and monovalent bindings. The former would improve thermal stability but not collagenase resistance, whereas the latter have negligible effects. Overall, this study provides a mechanistic understanding of the chemical crosslinking of ABPs, which will contribute to the future development of more efficient and economically viable strategies to produce bioprostheses. STATEMENT OF SIGNIFICANCE: Chemical crosslinking imparts suitable properties to acellular bovine pericardium (ABP) for clinical applications, yet the understanding is lacking on the structure-stability relationship especially under different crosslinking conditions. Structural evidence in this study differentiates the binding sites during crosslinking in collagen fibrils at different crosslinker concentrations, highlighting the excess usage in the conventional crosslinking treatments. The mechanism based on the structure of collagen also successfully explains the dissimilarity in hydrothermal and enzymatic stabilities with varied crosslinking conditions. Future researches focusing on developing biomaterials via chemical crosslinking of ABPs would benefit from this study, for its contribution to the better understanding of the relationship of collagen structure and functions.
PMID:36049624 | DOI:10.1016/j.actbio.2022.08.057
Post-esophagectomy chylothorax refractory to mass ligation of thoracic duct above diaphragm: a case report
Post-esophagectomy chylothorax is a relatively rare but potentially lethal complication. The treatment strategy of post-esophagectomy chylothorax remains a subject of debate which mainly focuses on the indicat… Read More
Robot-assisted endoscopic removal of a huge tricuspid valve myxoma: case report
Cardiac myxoma is the most common benign cardiac tumor. Its tremendous size and fragile character severely bother the surgeons. Several minimal invasive approaches had been applied for radical tumor excision. … Read More
Analysis of changes in “mitral valve reserve” after coronary artery bypass grafts in patients with functional mitral regurgitation
The treatment of moderate functionalmitral regurgitation (FMR) during coronary artery bypass grafting (CABG) is still debated. Our primary end point was to assess the improvement of “mitral valve reserve” (MVR… Read More
Expanding perigraft seroma after ascending aorta replacement
Perigraft seroma is a persistent and sterile fluid confined within a fibrous pseudomembrane surrounding a graft that develops after graft replacement. Development of perigraft seroma is an uncommon complicatio… Read More