Changes in the permeability of blood brain barrier and endothelial cell damage after cerebral ischemia

OBJECTIVE： To investigate the effect of endothelial cells on the permeability of blood brain barrier （BBB） after brain injury and its effect mechanism. DATA SOURCES： We searched for the articles of permeability of BBB and endothelial cell injury after brain is- chemia, which were published between January 1982 and December 2005, with the key words of ＂cerebral ischemia damage,blood brain barrier （ BBB）,permeability,effect of endothelial cell （EC） and its variation mechanism＂in English. STUDY SELECTION： The materials were primarily selected. The articles related to the changes in the permeability of BBB and the effect of endothelial cells as well as the change mechanism after cerebral ischemia damage were chosen. Repetitive studies or review articles were excluded. DATA EXTRACTION： Totally 55 related articles were collected, and 35 were excluded due to repetitive or review articles, finally 20 articles were involved. DATA SYNTHESIS： The content or viewpoints of involved literatures were analyzed. Cerebral ischemia had damage for endothelial cells, such as the inflow of a lot of Ca2^＋, the production of nitrogen monoxide and oxygen free radical, and aggravated destruction of BBB. After acceptors of inflammatory mediators on cerebrovascular endothelial cell membrane, such as histamine, bradykinin , 5-hydroxytryptamine and so on are activated, endothelial cells shrink and the permeability of BBB increases. Its mechanism involves in the inflow of extracellular Ca^＋2and the release of intracellular Ca^2＋ in the cells. Glycocalyx molecule on the surface of endothelial cell, having structural polytropy, is the determinative factor of the permeability of BBB. VEGF, intensively increasing the vasopermeability and mainly effecting on postcapillary vein and veinlet, is the strongest known blood vessel permeation reagent. Its chronic overexpression in the brain can lead the destruction of BBB. CONCLUSION： The injury of endothelial cell participants in the pathological mechanism of BBB destruction after cerebral ischemla.

Magnetic resonance imaging and cell-based neurorestorative therapy after brain injury

Restorative cell-based therapies for experimental brain injury, such as stroke and traumatic brain injury,substantially improve functional outcome. We discuss and review state of the art magnetic resonance imaging methodologies and their applications related to cell-based treatment after brain injury. We focus on the potential of magnetic resonance imaging technique and its associated challenges to obtain useful new information related to cell migration, distribution, and quantitation, as well as vascular and neuronal remodeling in response to cell-based therapy after brain injury. The noninvasive nature of imaging might more readily help with translation of cell-based therapy from the laboratory to the clinic.

Entropy Generation Analysis in Convective Ferromagnetic Nano Blood Flow Through a Composite Stenosed Arteries with Permeable Wall

The study of heat transfer is of significant importance in many biological and biomedical industry problems.This investigation comprises of the study of entropy generation analysis of the blood flow in the arteries with permeable walls. The convection through the flow is studied with compliments to the entropy generation. Governing problem is formulized and solved for low Reynold's number and long wavelength approximations. Exact analytical solutions have been obtained and are analyzed graphically. It is seen that temperature for pure water is lower as compared to the copper water. It gains magnitude with an increase in the slip parameter.