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[The effect of alphamethyltyrosine on cerebral vascular occlusive disease (author's transl)]
Abstract:
A double blind prospective study of the modification by alphamethyltyrosine (AMT) of experimental occulusion of the middle celebral artery (MCA) was performed on squirrel monkeys. The transorbital microsurgical technique was employed to expose the origin of the left MCA. A miniture Levis-Scoville clip was placed on the left MCA for 3 hours. Thirteen monkeys were given 10 ml/kg of 2% AMT solution approximately on hour prior to occlusion and just after revascularization. Thirteen control monkeys were given an equal volume of normal saline. After the removal of hte clip, detailed evaluation of neurological condition was recored every hour for 6 hours and at frequent intervals thereafter until the monkey expired or was sacrificed. The brain was perfused with biological carbon/saline solution and fixed glutaraldehyde using catheters placed in both common carotoid arteries. Brain samples were cut to 100 microns and examined with a light microscope. Immediately after the clip was placed on the MCA, all the animals demonstrated severe hemiparesis or hemiplegis of the contralateral side. When the clip was removed gradual recovery of function of the right side occured over a period of several hours. How,ever recovery was less complete in the control group, and even with seeming fair recovery of function in some animals, sudden death occured within 24 hours. Ten of the thirteen controls expired within 24 hours but only 2 AMT treated animals expired within 6 hours. Changes in blood pressure and gases due to AMT were negligible. In gross and microscopic examination, considerable brain edema with midline shift to the the contralateral side was observed in all untreated animals 6 hours after revascularization. Leakage of carbon, indicating microvasculature damage, occured in the infarcted areas and in the surrounding tissues. The sam degree of brain edema and infarction was observed in the AMT treated animals which were died within 6 hours after revascularization. Better perfusion with carbon black and less edema were, however, seen in other AMT treated animals 6 afters after revacularization...
Insights
Alphamethyltyrosine (AMT) reduced mortality and brain edema in squirrel monkeys experiencing middle cerebral artery (MCA) occlusion. AMT treatment improved neurological recovery and reduced microvasculature damage following experimental stroke.
Area of Science:
- Neuroscience
- Pharmacology
- Experimental Neurology
Context:
- Middle cerebral artery (MCA) occlusion is a common cause of ischemic stroke.
- Understanding neuroprotective agents is crucial for stroke treatment development.
- Experimental models in non-human primates are vital for studying stroke pathophysiology.
Purpose:
- To investigate the neuroprotective effects of alphamethyltyrosine (AMT) on experimental MCA occlusion in squirrel monkeys.
- To evaluate the impact of AMT on neurological recovery, mortality, and brain tissue damage post-occlusion.
Summary:
- A double-blind, prospective study utilized a transorbital microsurgical technique to occlude the MCA in squirrel monkeys for 3 hours.
- Thirteen monkeys received AMT, while thirteen controls received saline; neurological function, mortality, and brain histology were assessed.
- AMT treatment significantly reduced 24-hour mortality (2/13 vs. 10/13 controls) and mitigated brain edema and microvasculature damage.
Impact:
- Alphamethyltyrosine demonstrates potential as a neuroprotective agent in ischemic stroke models.
- Findings suggest AMT may reduce brain edema and improve outcomes following MCA occlusion.
- This research contributes to the development of novel therapeutic strategies for stroke patients.