Tissue engineering of endothelial cells (EC) and chemical engineering with anticoagulant moieties has been undertaken in order to improve prosthetic graft patency and thrombogenicity. This was done by covalently bonding a compliant poly(carbonate-urea)urethane graft (MyoLink) with arginine-glycine-aspartate (RGD) or/and heparin (Hep) to ascertain whether EC retention could be improved. The retention of these moieties and EC was assessed after exposure to pulsatile flow. We covalently bonded RGD, Hep, and RGD/Hep onto the luminal surface of MyoLink using spacer arm technology. Narrow-beam X-ray photoelectron spectroscopy was carried out to check the efficiency of the bonding. EC were radiolabeled and seeded onto native MyoLink and with 1) RGD-, 2) Hep-, and 3) RGD/Hep-bonded grafts and exposed to shear stress in a physiological flow circuit for 6 h, which reproduces femoral artery flow waveforms and pulsatility. Results were recorded on a gamma camera imaging system. Viability of cells was tested with a modified Alamar Blue assay (ABA) and scanning electron microscopy for morphological appearance of seeded cells. Experiments were repeated (n=6). RGD, Hep, and RGD/Hep were bonded together in a uniform distribution on the luminal surface of each graft type, and bioactivity of each moiety covalently bonded was very high. In the flow circuit, there was exponential cell retention for the first 60 min of flow for all the grafts, but after 6 h of exposure to pulsatile flow the RGD/Hep-bonded graft had a significantly better cell retention rate than native MyoLink (75.7%+/-2.3 vs. 60.5+/-10.1, P<0.05). ABA test showed that all the seeded cells postexposure to flow were viable, and significantly higher metabolic activity was recorded on a RGD/Hep-bonded graft than with MyoLink-seeded graft (P<0.01). Using RGD/Hep covalently bonded onto graft surfaces improves cell retention and provides an antithrombogenic surface for initial blood flow in vivo until full EC activity develops postseeding. This would allow the development and further improvement of hybrid grafts.

No abstract

The aim of sodding prosthetic grafts with endothelial cells (EC) is to establish a functioning antithrombogenic monolayer of EC. Application of basement membrane proteins improves EC adherence on ePTFE grafts. Their addition to a biodurable compliant poly(carbonate-urea)urethane graft (CPU) was studied with respect to EC adherence. Preclot, fibronectin, gelatin, and collagen were coated onto CPU. RGD peptide, heparin, and both RGD and heparin were chemically bonded to CPU. Human umbilical vein EC (HUVEC) labeled with 111-Indium oxine were sodded (1.8 x 10(6) EC/cm(2)) onto native and the modified CPU. The grafts were washed after 90 min and EC retention determined. The experiments were repeated six times. EC retention on native CPU was 1.0 +/- 0.2 x 10(5) EC/cm(2). The application of preclot, fibronectin, gelatin, and collagen did not improve EC retention, which was 0.8 +/- 0.1, 0.4 +/- 0.1, 0.3 +/- 0.08, and 0.5 +/- 0.2 x 10(5) EC/cm(2), respectively. Bonding RGD, heparin, and both RGD and heparin significantly improved EC retention to 1.9 +/- 0.6, 1.7 +/- 0.5, and 2.6 +/- 0.6 x 10(5) EC/cm(2), respectively (p < 0.01). Bonding of RGD, heparin, and both RGD and heparin accelerates and enhances EC retention onto CPU. Simple coating of basement membrane proteins confers no advantage over native CPU.

In this data set, there is a large array of titles, which appear to have little relationship with other factors like education. This is confusing to the public, employers and those commissioning services. It also demonstrates that the previous assumptions by Council for Healthcare Regulatory Excellence that advanced practice labels are associated with career progression are unsound and should be addressed by the regulator.

No abstract

Tissue engineering of the small intestine remains experimental despite worldwide attempts to develop a functional substitute for short bowel syndrome. Most published studies have reported predominant use of PLLA (poly-L-lactide acid)/PGA (polyglycolic acid) copolymer as the scaffold material, and studies have been limited by in vivo experiments. This lack of progress has inspired a fresh perspective and provoked further investigation and development in this field of tissue engineering. In the present paper, we exploit a relatively new nanocomposite of POSS (polyhedral oligomeric silsesquioxane) and PCL [poly(caprolactone-urea)urethane] as a material to develop porous scaffolds using a solvent casting/particulate leaching technique to fabricate porous scaffolds in different pore sizes and porosities. Scaffolds were characterized for pore morphology and porosity using scanning electron microscopy and micro-computed tomography. Rat intestinal epithelial cells were then seeded on to the polymer scaffolds for an in vitro study of cell compatibility and proliferation, which was assessed by Alamar Blue™ and lactate dehydrogenase assays performed for 21 days post-seeding. The results obtained demonstrate that POSS–PCL nanocomposite was produced as a macroporous scaffold with porosity over the range of 40–80% and pore size over the range of 150–250 μm. This scaffold was shown to support epithelial cell proliferation and growth. In conclusion, as a further step in investigating small intestinal tissue engineering, the nanocomposite employed in this study may prove to be a useful alternative to poly(lactic-co-glycolic acid) in the future.

Magnetic beads (Dynabeads) have been used for the purification of endothelial cells. One application for this procedure may be for single-stage seeding of bypass grafts. The number of endothelial cells (EC) isolated is crucial and therefore to increase the number of cells extracted, a higher number of Dynabeads per cell may need to be used. The effect of large numbers of CD31 Dynabeads on cell proliferation/metabolism is unknown. We undertook this study using CD31-coated Dynabeads and EC from human umbilical vein. EC were coated at concentrations of 4, 10, or 50 beads per cell. The cells were cultured for 6 days with control being normal EC. Cellular proliferation was assessed by trypsinization of cells and metabolism assessed with an Alamar blue viability assay. In a further experiment a compliant polyurethane graft was single-stage seeded with both coated Dynabeads and normal EC. The results showed that using a higher number of beads per cell resulted in a reduction in cell proliferation and a reduction in cell metabolism. The total number of Dynabeads-coated cells in culture compared to controls (%) by day 6 were 30.7 +/- 2.56, 41.3 +/- 9.8 and 59.2 +/- 7.3 for 50, 10, and 4 beads per cell, respectively. The corresponding results for Alamar blue were 43.7 +/- 1.2, 61.8 +/- 1.4, and 72.1 +/- 4.3. The seeded grafts showed reduced metabolism with the Dynabeads-coated EC. In conclusion, high numbers of beads per cell have a late detrimental effect on cell proliferation and metabolism. Therefore for single-stage seeding lower numbers of Dynabeads will need to be used with resultant reduction in the number of available EC.

Background The Coroners and Justice Act allows coroners in England or Wales to issue reports after inquest, if they believe that action should be taken to prevent a future death. Coroners are under a statutory duty to issue a Prevention of Future Death (PFD) report to persons or organisations that they believe have the power to act. Cumulatively, these reports may contain useful intelligence for patient safety. The aim of this study was to examine the feasibility of extracting data from these reports and to evaluate if learning was possible from any common themes. Methods Reports were extracted from 2016 to 2019 for deaths in hospitals, care homes and the community in England and Wales. These were subjected to descriptive statistics and thematic analysis of coroner’s concerns. Application of data mining techniques was not possible due to data quality. Results 710 reports were examined, with 3469 concerns being raised (mean 4.88, range 1–33). 36 reports expressed concern about having to issue repeat PFDs to the same organisation for the same or similar concerns. Thematic analysis reliability was high ( κ 0.89 unweighted) with five emerging primary themes: deficit in skill or knowledge, missed, delayed or uncoordinated care, communication and cultural issues, systems issues and lack of resources. A codebook of 53 subthemes were identified. Conclusions PFD reports offer valuable insight. Aggregation and continued analysis of these reports could offer more informed patient safety, workforce development and organisational policy. Improved data quality would allow for possible automation of analysis and faster feedback into practice.