In a panel of early-passage brain tumor cultures from patients, high levels of GSTP1 transcripts and protein were associated with wild-type p53 and, conversely, low GSTP1 levels with mutant p53.
The only hamster for which third-passage brain homogenate resulted in a decrease in incubation period was the Chinese hamster.
To demonstrate PrPres sensitivity to PK, we adjusted 20 μL of a 20% (wt/vol) third-passage brain homogenate in 0.01 M Tris, pH 7.3, from each species to 100 mmol/L Tris HCl, pH 8.3, 1% Triton X-100, and 1% sodium deoxycholate.
For secondary passages, brain from a mouse that succumbed to TSE during first passage was used to prepare a 1% (w/v) homogenate in sterile saline.
Because thyroid hormone passage across brain barriers is a precondition for its action in the CNS, and because brain is an important target of thyroid hormone action, we investigated the role of transthyretin in mediating thyroid hormone access to and distribution within the brain in a transthyretin-null mouse model system.
Secondary passage of brain homogenate from these animals was free of scrapie infectivity (survival>200 days).
Secondary passage of brain homogenates was conducted from animals in all reaction groups.
In these cases, subsequent passage of brain material from the challenged individuals to additional mice did produce clinical disease, thereby demonstrating that asymptomatic animals can harbour high levels of infectious prions in their brains.
Therefore, lipophilicity does not seem to be necessary or lonely factor that may assist the drug for safe passage to brain.
Additionally, a second passage using brain material from the only mouse showing a Roboscreen® positive and immunodeposits in plaque provided positive results by this same technique as well as clinical signs within 7 8 months post-inoculation in all mice inoculated (data not shown).
Correspondingly, repeated air sac inoculation of a low-pathogenic H5N3 isolate in 1-day-old-chickens did not lead to high virulence for 4-to-6-week-old chickens, whereas only two further passages in brain yielded an HPAIV [49].
