The time course of steroid action on blood-to-brain and blood-to-tumor transport of 82Rb: A positron emission tomographic study
Blood-to-brain and blood-to-tumor transport rate constants for Rb (K1) and apparent tissue blood volume (Vb) were estimated in 8 patients with primary or metastatic brain tumors before and approximately 6 hours after a 100-mg intravenous bolus injection of dexamethasone using /sup 82/Rb and positron emission tomography. Eight additional patients were studied to evaluate test-retest variability and repositioning errors. Six hours following dexamethasone administration tumor K1 (but not Vb) was significantly reduced compared with contralateral control brain regions (p less than 0.03). These data are consistent with our previously published 24-hour-postdexamethasone data and suggest that comparable effects of corticosteroids on brain/tumor capillaries may be observed at 5 to 6 and 24 hours. The time course of dexamethasone-induced alterations in brain/tumor capillary permeability supports the view that these alterations may be responsible for at least some of the antiedema effects of corticosteroids.
- Research Organization:
- Memorial Sloan-Kettering Cancer Center, New York, NY (USA)
- OSTI ID:
- 5766997
- Journal Information:
- Ann. Neurol.; (United States), Vol. 25:3
- Country of Publication:
- United States
- Language:
- English
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BLOOD-BRAIN BARRIER
PERMEABILITY
BRAIN
POSITRON COMPUTED TOMOGRAPHY
DEXAMETHASONE
BIOLOGICAL EFFECTS
METASTASES
NEOPLASMS
PATIENTS
RUBIDIUM 82
ADRENAL HORMONES
ALKALI METAL ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CENTRAL NERVOUS SYSTEM
COMPUTERIZED TOMOGRAPHY
CORTICOSTEROIDS
DIAGNOSTIC TECHNIQUES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
EMISSION COMPUTED TOMOGRAPHY
GLUCOCORTICOIDS
HOURS LIVING RADIOISOTOPES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
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KETONES
MINUTES LIVING RADIOISOTOPES
NERVOUS SYSTEM
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PREGNANES
RADIOISOTOPES
RUBIDIUM ISOTOPES
STEROIDS
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550601* - Medicine- Unsealed Radionuclides in Diagnostics