Blood-brain barrier changes

Brain Studies. Rubidium-82 has also been used to study blood brain barrier changes in patients with brain tumors or Alzheimer s type senile dementia (28-30). The method of study is similar to the heart studies without gating. Figure 11 shows the uptake of Rb-82 in the three levels of a brain tumor. This non-invasive procedure provides information on the size and vascularity of the tumor. In the slice OM + 10 there is a vascular rim and a necrotic center in the tumor. The metabolism of glucose was determined in the same tumor patient using F-fluorodeoxyglucose produced on a cyclotron and the results correlated well with Rb-82 distribution. 

Barzo, P, Marmarou, A., Fatouros, P., Corwin, F., and Dunbar, J., Magnetic resonance imaging-monitored acute blood-brain barrier changes in experimental traumatic brain injury, J. Neurosurg., 85(6), 1113, 1996. 

Intense neuroinflammation/increased permeability of the blood-brain barrier/changes in biochemical processes/neuronal cell death from compromised cellular integrity, release of neurotransmitters and excitotoxicity... 

However, more recently, a functionally selective inhibitor of nNOS has been described — 7-nitroindazole (7-NI). It is puzzling that in vitro this compound has no selectivity for nNOS over eNOS but after systemic administration, fails to change blood pressure yet alters neuronal responses that are thought to result from production of NO. A suggested resolution of this action is that 7-NI is metabolised in the periphery but not the CNS, so that once it has crossed the blood-brain barrier, it can only act on nNOS. 

Studies investigating the transfer of phytoestrogens from the peripheral blood brain barrier to the CNS have indicated that the concentrations of isoflavones in the CNS are several orders of magnitude lower than in the blood stream. This suggests that phytoestrogens do not efficiently cross the blood brain barrier in rodents (Chang et al, 2000 Coldham and Sauer, 2000). 

Once through the blood-brain barrier, pathogens thrive and replicate due to limited host defenses in the CNS. Figure 67-1 depicts the pathophysiologic changes associated... 

Stewart PA, Hayakawa EM. Interen-dothelial junctional changes underlie the developmental tightening of the blood-brain barrier. Dev Brain Res 1987 32 271-281. 

P. Jolliet-Riant and J.-P. Tillement, Drag and nutrient transfers through the blood-brain barrier and their pharmacological changes, Encephale 25 135 (1999). 

Sundstrom, R., K. Muntzing, H. Kalimo, and R Sourander. 1985. Changes in the integrity of the blood-brain barrier in suckling rats with low dose lead encephalopathy. Acta Neuropathol. 68 1-9. 

Neurological effects occurred in animals exposed to endrin. Behavioral effects (Gray et al. 1981), hyperexcitability, tremors, and convulsions (Deichmann et al. 1970 NCI 1978 Treon et al. 1955) were reported. Irregular EEG recordings were observed in rats (Speck and Maaske 1958). There is some evidence to show that occurrence of convulsions is related to blood-brain barrier permeability changes (Speck and Maaske 1958). 

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