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Title: Blood-brain barrier alteration after microwave-induced hyperthermia is purely a thermal effect: I. Temperature and power measurements

Abstract

The effect of microwave-induced hyperthermia on the blood-brain barrier was studied in 21 Sprague-Dawley rats. Under sodium pentobarbital anesthesia, animals were place in a stereotactic frame, and an interstitial microwave antenna operating at 2450 MHz was inserted in a bony groove drilled parallel to the sagittal suture. Some antennae were equipped with an external cooling jacket. Temperature measurements were made lateral to the antenna by fluoroptical thermometry, and power was calculated from the time-temperature profile. Five minutes prior to termination of microwave irradiation, horseradish peroxidase (1 mg/20 g body weight) was injected intravenously. Extravasation of horseradish peroxidase was observed in brain tissue heated above 44.3 degrees C for 30 minutes and at 42.5 degrees C for 60 minutes. Microwave irradiation failed to open the blood-brain barrier when brain temperatures were sustained below 40.3 degrees C by the cooling system. Extravasation of blood-borne peroxidase occurred at sites of maximal temperature elevation, even when these did not coincide with the site of maximum power density. The data suggest that microwave-induced hyperthermia is an effective means for opening the blood-brain barrier and that the mechanism is not related to the nonthermal effect of microwaves.

Authors:
; ;  [1]
  1. (Univ. of Maryland School of Medicine, Baltimore (USA))
Publication Date:
OSTI Identifier:
6139083
Resource Type:
Journal Article
Resource Relation:
Journal Name: Surgical Neurology (Tryon, N.C.); (USA); Journal Volume: 35:3
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; BLOOD-BRAIN BARRIER; SENSITIVITY; MICROWAVE RADIATION; BIOLOGICAL EFFECTS; HYPERTHERMIA; PEROXIDASES; RATS; ANIMALS; BODY TEMPERATURE; ELECTROMAGNETIC RADIATION; ENZYMES; MAMMALS; OXIDOREDUCTASES; RADIATIONS; RODENTS; VERTEBRATES; 560400* - Other Environmental Pollutant Effects

Citation Formats

Moriyama, E., Salcman, M., and Broadwell, R.D. Blood-brain barrier alteration after microwave-induced hyperthermia is purely a thermal effect: I. Temperature and power measurements. United States: N. p., 1991. Web. doi:10.1016/0090-3019(91)90068-K.
Moriyama, E., Salcman, M., & Broadwell, R.D. Blood-brain barrier alteration after microwave-induced hyperthermia is purely a thermal effect: I. Temperature and power measurements. United States. doi:10.1016/0090-3019(91)90068-K.
Moriyama, E., Salcman, M., and Broadwell, R.D. Fri . "Blood-brain barrier alteration after microwave-induced hyperthermia is purely a thermal effect: I. Temperature and power measurements". United States. doi:10.1016/0090-3019(91)90068-K.
@article{osti_6139083,
title = {Blood-brain barrier alteration after microwave-induced hyperthermia is purely a thermal effect: I. Temperature and power measurements},
author = {Moriyama, E. and Salcman, M. and Broadwell, R.D.},
abstractNote = {The effect of microwave-induced hyperthermia on the blood-brain barrier was studied in 21 Sprague-Dawley rats. Under sodium pentobarbital anesthesia, animals were place in a stereotactic frame, and an interstitial microwave antenna operating at 2450 MHz was inserted in a bony groove drilled parallel to the sagittal suture. Some antennae were equipped with an external cooling jacket. Temperature measurements were made lateral to the antenna by fluoroptical thermometry, and power was calculated from the time-temperature profile. Five minutes prior to termination of microwave irradiation, horseradish peroxidase (1 mg/20 g body weight) was injected intravenously. Extravasation of horseradish peroxidase was observed in brain tissue heated above 44.3 degrees C for 30 minutes and at 42.5 degrees C for 60 minutes. Microwave irradiation failed to open the blood-brain barrier when brain temperatures were sustained below 40.3 degrees C by the cooling system. Extravasation of blood-borne peroxidase occurred at sites of maximal temperature elevation, even when these did not coincide with the site of maximum power density. The data suggest that microwave-induced hyperthermia is an effective means for opening the blood-brain barrier and that the mechanism is not related to the nonthermal effect of microwaves.},
doi = {10.1016/0090-3019(91)90068-K},
journal = {Surgical Neurology (Tryon, N.C.); (USA)},
number = ,
volume = 35:3,
place = {United States},
year = {Fri Mar 01 00:00:00 EST 1991},
month = {Fri Mar 01 00:00:00 EST 1991}
}