scholarly journals Endothelin Levels Increase in Rat Focal and Global Ischemia

1994 ◽  
Vol 14 (2) ◽  
pp. 337-342 ◽  
Author(s):  
F. C. Barone ◽  
M. Y.-T. Globus ◽  
W. J. Price ◽  
R. F. White ◽  
B. L. Storer ◽  
...  

Endothelin-1, a peptide exhibiting extremely potent cerebral vasoactive properties, is elevated in the cerebrospinal fluid after hemorrhagic stroke and implicated in cerebral vasospasm. The purpose of this study was to determine changes in endothelin in ischemic rat brain by assaying endothelin tissue and extracellular levels. Immunoreactive endothelin levels in ischemic brain tissue following permanent or transient focal ischemia produced by middle cerebral artery occlusion was determined. In addition, endothelin levels were assayed in striatal extracellular fluid collected by microdialysis before, during, and after global ischemia produced by two-vessel occlusion combined with hypotension. Twenty-four hours after the onset of permanent middle cerebral artery occlusion, the ischemic cortex level (0.58 ± 0.27 fmol/mg protein) of immunoreactive endothelin was significantly (p < 0.05) increased, by 100%, over that in the nonischemic cortex (0.29 ± 0.13 fmol/mg protein). Transient artery occlusion for 80 min with reperfusion for 24 h also resulted in a similar significant (p < 0.05) increase, 78%, in immunoreactive endothelin in the ischemic zone. Global forebrain ischemia significantly (p < 0.05) increased the level of immunoreactive endothelin collected in striatal microdialysis perfusate, from a basal level of 14.6 ± 6.7 to 26.5 ± 7.7 and 26.2 ± 7.4 amol/μl (i.e. 82 and 79%). These changes reflect the relative picomolar extracellular concentration increases during ischemia and following reperfusion, respectively. This is the first demonstration of elevated levels of endothelin in focal ischemic tissue and in the extracellular fluid in global ischemia and suggests a role of the peptide in ischemic and postischemic derangements of cerebral vascular function and tissue injury.

1996 ◽  
Vol 16 (5) ◽  
pp. 881-891 ◽  
Author(s):  
Masayuki Miyabe ◽  
Susumu Mori ◽  
Peter C. M. van Zijl ◽  
Jeffrey R. Kirsch ◽  
Scott M. Eleff ◽  
...  

Magnetic resonance water diffusion imaging can detect early ischemic changes in stroke. Using a middle cerebral artery occlusion model, we examined which range of values of the orientation-independent diffusion quantity [Formula: see text] is an early noninvasive indicator of reduced cerebral perfusion and focal brain injury. Cats underwent either a 30-min occlusion followed by 3.5 h reperfusion (n = 7) or a 60-min occlusion followed by 4-h reperfusion (n = 6). Repeated measurements of CBF were made with radiolabeled microspheres, and acute focal injury was measured with triphenyltetrazolium chloride (TTC) staining. During occlusion, the decrease in Dav correlated with CBF for caudate [30-min occlusion (n = 13): p < 0.0001; 60-min occlusion (n = 6): p < 0.02] and for cortex [30-min occlusion (n = 12): p < 0.0001; 60-min occlusion (n = 5): p < 0.04]. Variable caudate and hemispheric injury levels were found among cats in both groups. The area of tissue injury demarcated by TTC began to correlate with the area of reduced Dav by 30 min of occlusion (p < 0.02), and this correlation improved (p < 0.0001) at 1, 1.5, and 2.0 h after the onset of occlusion. The time necessary to reach a one-to-one correspondence between the percent of hemisphere injured and the percent of hemispheric area with Dav < 0.65 × 10−9 m2/s was 2 h after occlusion. Thus, the absolute value of Dav is a good indicator of the risk of tissue injury, whereas the combination of Dav and the length of time of Dav reduction is an excellent predictor of acute focal tissue injury demarcated by TTC staining.


Author(s):  
Phillip A. Bonney ◽  
Parampreet Singh ◽  
Benjamin Yim ◽  
William J. Mack

Abstract: This chapter addresses the neurosurgical management of stroke due to acute middle cerebral artery occlusion. Large vessel occlusion is a common mechanism of acute ischemic stroke. Mechanical thrombectomy has emerged as an important procedure that drastically improves outcomes in this disease. This chapter discusses the diagnosis and treatment of acute ischemic stroke from large vessel occlusion, including the rapid radiographic evaluation with CT, CTA, MRI, and perfusion imaging. The scoring of the stroke using scales such as the ASPECTS score and their use in decision-making is reviewed. The chapter then discusses treatment with both chemical thrombolysis and mechanical thrombectomy, including the technical aspects of the procedure.


1995 ◽  
Vol 15 (4) ◽  
pp. 639-646 ◽  
Author(s):  
Thomas Nikolaj Sager ◽  
Henning Laursen ◽  
Anker Jon Hansen

N-Acetyl-aspartate (NAA) is almost exclusively localized in neurons in the mature brain and might be used as a neuronal marker. It has been reported that the NAA content in human brain is decreased in neurodegenerative diseases and in stroke. Since the NAA content can be determined by nuclear magnetic resonance techniques, it has potential as a diagnostic and prognostic marker. The objective of this study was to examine the change of NAA content and related substances following cerebral ischemia and compare the results to the damage of the tissue. We used rats to study the changes of NAA, N-acetyl-aspartyl-glutamate (NAAG), glutamate, and aspartate contents over a time course of 24 h in brain regions affected by either permanent middle cerebral artery occlusion (focal ischemia) or decapitation (global ischemia). The decreases of NAA and NAAG contents following global brain ischemia were linear over time but significant only after 4 and 2 h, respectively. After 24 h, the levels of NAA and NAAG were 24 and 44% of control values, respectively. The concentration of glutamate did not change, whereas the aspartate content increased at a rate comparable with the rate of decrease of NAA content. This is consistent with NAA being preferentially degraded by the enzyme amidohydrolase II in global ischemia. In focal ischemia, there was a rapid decline of NAA within the first 8 h of ischemia followed by a slower rate of reduction. The reductions of NAA and NAAG contents in focal ischemia were significant after 4 and 24 h, respectively. After 24 h, the NAA and NAAG contents were 33 and 64% of control values, respectively. Also, the glutamate and aspartate contents exhibited significant decreases in focal ischemic tissue. Our studies show that NAA decreases during brain ischemia, the initial rate being faster in focal ischemia than in global ischemia. In rat transient focal ischemia, others have shown that a middle cerebral artery occlusion of 2- to 3-h duration is sufficient to produce an infarct that is similar in size to that following permanent occlusion for 24 h. The fact that we observed only a 10% decrease of NAA content 2 h after occlusion demonstrates that the NAA content of the tissue does not reflect neuronal viability. Thus, the incompetence with which ischemic/infarcted tissue removes NAA will lead to overestimation of the number of viable neurons in acute situations. Only when steady state prevails may [NAA] be used as a marker of viable nerve cells.


2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S217-S217
Author(s):  
Kentaro Deguchi ◽  
Mikiro Takaishi ◽  
Takeshi Hayashi ◽  
Atsuhiko Oohira ◽  
Shoko Nagotani ◽  
...  

Stroke ◽  
2002 ◽  
Vol 33 (4) ◽  
pp. 1129-1134 ◽  
Author(s):  
Nikolaos Kostulas ◽  
Hu-Lun Li ◽  
Bao-Guo Xiao ◽  
Yu-Min Huang ◽  
Vasilios Kostulas ◽  
...  

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