Temporal changes in perivascular concentrations of oxyhemoglobin, deoxyhemoglobin, and methemoglobin after subarachnoid hemorrhage
| Autor: | John K. B. Afshar, Robert J. Boock, Ryszard M. Pluta, Edward H. Oldfield |
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| Rok vydání: | 1998 |
| Předmět: |
Microdialysis
Time Factors Subarachnoid hemorrhage Sodium Chloride Nitric Oxide Hemolysis Methemoglobin Catheterization Central nervous system disease Hemoglobins Cerebral vasospasm medicine Animals cardiovascular diseases Analysis of Variance Endothelin-1 medicine.diagnostic_test business.industry Exudates and Transudates Cerebral Arteries Subarachnoid Hemorrhage medicine.disease Cerebral Angiography nervous system diseases Disease Models Animal Macaca fascicularis medicine.anatomical_structure Ischemic Attack Transient Spectrophotometry Oxyhemoglobins Anesthesia Hemoglobin business Craniotomy Blood vessel Cerebral angiography |
| Zdroj: | Journal of Neurosurgery. 88:557-561 |
| ISSN: | 1933-0693 0022-3085 |
| DOI: | 10.3171/jns.1998.88.3.0557 |
| Popis: | Hemoglobin released from hemolysed erythrocytes has been postulated to be responsible for delayed cerebral vasospasm after subarachnoid hemorrhage (SAH). However, the evidence is indirect and the mechanisms of action are unclear. Cerebrovascular tone is regulated by a dynamic balance of relaxing and contracting factors. Loss of the endothelium-derived relaxing factor—nitric oxide in the presence of oxyhemoglobin and overproduction of endothelin-1 stimulated by oxyhemoglobin have been postulated as causes of delayed cerebral vasospasm after SAH.Object. The authors aimed to investigate this hypothesis using in vivo microdialysis to examine time-dependent changes in the perivascular concentrations of oxyhemoglobin, deoxyhemoglobin, and methemoglobin in a primate model of SAH.Methods. Nine cynomolgus monkeys underwent right-sided frontotemporal craniectomy and placement of a semipermeable microdialysis catheter adjacent to the right middle cerebral artery (MCA). Saline (control group, three animals) or an arterial blood clot (SAH group, six animals) was then placed around the MCA and the catheter. Arteriographically confirmed vasospasm had developed in all animals with SAH but in none of the control animals on Day 7. The dialysate was collected daily for 12 days. Levels of oxyhemoglobin, deoxyhemoglobin, and methemoglobin were measured by means of spectrophotometry.Perivascular concentrations of oxyhemoglobin, deoxyhemoglobin, and methemoglobin peaked on Day 2 in the control monkeys and could not be detected on Days 5 to 12. Perivascular concentrations of oxyhemoglobin and deoxyhemoglobin peaked on Day 7 in the SAH group, at which time the concentrations in the dialysate were 100-fold higher than in any sample obtained from the control animals. Methemoglobin levels increased only slightly, peaking between Days 7 and 12, at which time the concentration in the dialysate was 10-fold higher than in samples from the control animals.Conclusions. This study provides in vivo evidence that the concentrations of oxyhemoglobin and deoxyhemoglobin increase in the cerebral subarachnoid perivascular space during the development of delayed cerebral vasospasm. The results support the hypothesis that oxyhemoglobin is involved in the pathogenesis of delayed cerebral vasospasm after SAH and implicate deoxyhemoglobin as a possible vasospastic agent. |
| Databáze: | OpenAIRE |
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