Canines are typically used as the standard preclinical model to gauge the success of vascular graft materials. However, canines spontaneously re-endothelialize vascular grafts, whereas humans do not, even after years. This raises questions of why there are differences in vascular healing between humans and other species and whether the canine is the appropriate preclinical model. In the present study we evaluated human and canine endothelial cell (EC) migration on the novel cross-linked collagen biomaterial PhotoFix(TM) pericardium. We compared in vitro migration of these cells on PhotoFix alone and on PhotoFix adsorbed with various growth factors (aFGF and bFGF) and adhesion proteins (fibronectin, collagen IV, vitronectin, and laminin). We also compared human and canine ECs in terms of their morphologies and prostacyclin production. We found that human umbilical vein ECs (HUVECs) and canine ECs (CECs) migrated well on PhotoFix, suggesting that this biomaterial may be a good vascular graft candidate. Both cell types responded similarly to different growth factors and adhesive proteins, but HUVEC migration was consistently higher than that for CECs. This suggested that human in vivo graft re-endothelialization is likely not hindered by poor endothelial migration but is hindered by other cellular or graft properties.
There are guidelines in India for assisted reproductive technology but not specifically for posthumous assisted reproduction. The ethical concerns of using sperm from a dead man either with his explicit prior consent or by inferred consent, which is not easy to determine, need to be examined. Risks associated with this medical procedure, such as possible genetic defects, must be researched further. Questions about a time limit on storage of the sperm and its specific recipient are also important. Although a case of posthumous retrieval of sperm has not been reported in India, such a request may soon arise and it is time to start discussing these issues.
The article contains a brief description of some basic principles of neuroscience with hints and examples of how they can be applied to executive coaching. The author has been using these principles actively in his coaching practice for the past five years. It is hoped that this article will motivate new and experienced coaches to invest in learning and applying these (and other) neuroscience principles in their coaching practice.
Generally, plastic is made up of non-biodegradable chemicals i.e. polyolefin, polyester, and polyurethanes. This is hardly surprising since the use of polythene bags has infiltrated all sectors of economy, agriculture, consumer goods, and especially in packaging, where polythene is increasingly replacing jute, paper, wood, and glass. Polythene bags can release harmful chemicals into the surrounding agricultural soil, which can then seep into ground water or other surrounding water sources. This can cause serious harm to the species that drink this water. Unlike natural organic material they do not disintegrate with time but keep accumulating in the environment. So it is very difficult to dispose of the polythene bags. If the polythene bags burned in agriculture land, they release harmful chemicals like Cd, Pb, CO, NOX and SO2, which causes many diseases in animals as well as in human beings. The accumulation of polythene bags also makes agricultural soil sterile/barren as it stops the gaseous exchange. In normal agricultural land, the concentration of oxygen is 3 ppm. Where polythene is present, the concentration of oxygen in soil decreases to 0.001 ppm. In addition, the polythene pollution can adversely affect agricultural lands, waterways, and oceans.
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