Cerebrovascular and metabolic effects on the rat brain of focal Nd:YAG laser irradiation

Journal Article · Sat Dec 01 00:00:00 EST 1990 · Journal of Neurosurgery; (USA)

DOI:https://doi.org/10.3171/jns.1990.73.6.0909· OSTI ID:6064469

Kiessling, M; Herchenhan, E; Eggert, H R ^[1]

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1. Univ. of Heidelberg (Germany, F.R.)

To investigate the effects of focal neodymium:yttrium-aluminum-garnet (Nd:YAG) laser irradiation (lambda = 1060 nm) on regional cerebral blood flow, cerebral protein synthesis, and blood-brain barrier permeability, the parietal brain surface of 44 rats was irradiated with a focused laser beam at a constant output energy of 30 J. Survival times ranged from 5 minutes to 48 hours. Laser irradiation immediately caused well-defined cortical coagulation necrosis. Within 5 minutes after unilateral irradiation, 14C-iodoantipyrine autoradiographs demonstrated severely reduced blood flow to the irradiation site and perilesional neocortex, but a distinct reactive hyperemia in all other areas of the forebrain. Apart from a persistent ischemic focus in the vicinity of the cortical coagulation necrosis, blood flow alterations in remote areas of the brain subsided within 3 hours after irradiation. Autoradiographic assessment of 3H-tyrosine incorporation into brain proteins revealed rapid onset and prolonged duration of protein synthesis inhibition in perifocal morphologically intact cortical and subcortical structures. Impairment of amino acid incorporation proved to be completely reversible within 48 hours. Immunoautoradiographic visualization of extravasated plasma proteins using 3H-labeled rabbit anti-rat immunoglobulins-showed that, up to 1 hour after irradiation, immunoreactive proteins were confined to the neocortex at the irradiation site. At 4 hours, vasogenic edema was present in the vicinity of the irradiation site and the subcortical white matter, and, at later stages (16 to 36 hours), also extended into the contralateral hemisphere. Although this was followed by a gradual decrease in labeling intensity, resolution of edema was still not complete after 48 hours.

• OSTI ID: 6064469
• Journal Information: Journal of Neurosurgery; (USA), Vol. 73:6; ISSN 0022-3085
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
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LASER RADIATION
BIOLOGICAL EFFECTS
AUTORADIOGRAPHY
BIOSYNTHESIS
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LABELLED COMPOUNDS
LASERS
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ORGANIC COMPOUNDS
ORGANS
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RODENTS
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