PMID- 7941966
OWN - NLM
STAT- MEDLINE
DCOM- 19941024
LR  - 20161123
IS  - 0065-1427 (Print)
IS  - 0065-1427 (Linking)
VI  - 156
DP  - 1994
TI  - Pathophysiological aspects of malignant brain tumors studied with positron 
      emission tomography.
PG  - 1-35
AB  - To further understand the control of brain tumor fluid balance and pH, the 
      following studies were undertaken. The transport of a water soluble molecule 
      across the brain and tumor capillary endothelium was studied during 
      glucocorticoid and radiation treatment. The brain and brain-tumor acidity (pH) 
      was evaluated as a single measurement in patients receiving a low maintenance 
      dose of glucocorticoid. Transport changes and pH were measured in 61 patients 
      with cerebral tumors using 82Rubidium (82Rb) and 11C-Dimethyloxa-zolidindione 
      (11C-DMO), respectively, and Positron Emission Tomography (PET). Supplementary 
      studies of tumor and contralateral brain blood flow and blood volume using the 
      C15O2/PET and C15O/PET technique, respectively, were included to validate the 
      82Rb/PET model and obtain further information. A total of 125 PET scans were 
      performed. Supplementary studies were undertaken to estimate delay of blood 
      registration and form distribution of arterial blood isotope activity curves. 
      Blood-to-tumor barrier transport was outlined at baseline and at 6 and 24 hours 
      after the start of glucocorticoid treatment, finding a significant decrease in 
      the transport. Radiation treatment (2-6 gray) did not alter the blood-to-tumor 
      barrier transport when restudied within one hour in patients receiving 
      glucocorticoid. In accordance with others, we observed pH values in gray and 
      white matter in the range of 6.74-7.09 and 6.77-7.03 respectively. The pH in 
      brain tumors was as high as 6.88-7.26, suggesting that tumors are more alkalotic 
      than the normal brain. The permeability surface area product and the permeability 
      coefficient were determined from the 82Rb/PET transport and C15O2/PET flow 
      studies. Baseline permeability values were comparable to the literature values 
      both for 82Rb and potassium. No difference in tissue blood volume was seen 
      between 82Rb/PET and C15O/PET models and was of the same magnitude in the tumor 
      and the contralateral tissue. The pH and fluid control in human brain tumors are 
      perceived as metabolically controlled rather than, as previously believed, a 
      result of simple passive exchange of alkalotic or osmotic active molecules 
      between plasma and tumor interstitial space. Aspects of tumor alkalosis, tumor 
      edema production, glucocorticoid edema clearance, and relationship between the 
      anti-edema effect of glucocorticoid and the shown transport changes to 82Rb will 
      be reviewed in the light of metabolic control mechanisms.
FAU - Jarden, J O
AU  - Jarden JO
LA  - eng
PT  - Journal Article
PL  - Denmark
TA  - Acta Neurol Scand Suppl
JT  - Acta neurologica Scandinavica. Supplementum
JID - 0370337
RN  - 0 (Rubidium Radioisotopes)
RN  - 7S5I7G3JQL (Dexamethasone)
SB  - IM
MH  - Acid-Base Equilibrium/drug effects/physiology/radiation effects
MH  - Adult
MH  - Blood-Brain Barrier/drug effects/*physiology/radiation effects
MH  - Brain Neoplasms/diagnostic imaging/*physiopathology/therapy
MH  - Capillary Permeability/drug effects/physiology/radiation effects
MH  - Combined Modality Therapy
MH  - Cranial Irradiation
MH  - Dexamethasone/administration & dosage
MH  - Dominance, Cerebral/drug effects/physiology/radiation effects
MH  - Female
MH  - Humans
MH  - Male
MH  - Radiotherapy Dosage
MH  - Rubidium Radioisotopes/pharmacokinetics
MH  - *Tomography, Emission-Computed
MH  - Water-Electrolyte Balance/drug effects/physiology/radiation effects
EDAT- 1994/01/01 00:00
MHDA- 1994/01/01 00:01
CRDT- 1994/01/01 00:00
PHST- 1994/01/01 00:00 [pubmed]
PHST- 1994/01/01 00:01 [medline]
PHST- 1994/01/01 00:00 [entrez]
PST - ppublish
SO  - Acta Neurol Scand Suppl. 1994;156:1-35.