Prolonged challenge

QUESTION I find the technique of challenging the animals with various typic agents quite intriguing for assessment after prolonged exposure to MDMA or amphetamine. How long do those changes last I saw in your slide something on the order of 2 weeks or a few days after the MDMA treatment. If you would come back a few months later, would that supersensitivity still exist ... 

In sensitized asthmatic individuals, antigen challenge generally causes a Type I (IgE-mediated) immediate hypersensitivity response by release of preformed mediators, including histamine, and prostaglandins, which are responsible for bronchoconstric-tion and increased vascular permeability. Between 2 and 8 hours after the immediate response, asthmatics experience a more severe and prolonged (late phase) reaction that is characterized by mucus hyper-secretion, bronchoconstriction, airway hyperresponsiveness to a variety of nonspecific stimuli (e.g., histamine, methacholine), and airway inflammation characterized by eosinophils. This later response is driven by leukotrienes, chemokines and cytokines synthesized by activated mast cells and Th2 cells. Both proteins and haptens have been associated with these types of reactions. 

Shah, R.R. (2005) Drugs, QTc interval prolongation and final ICH E14 guideline an important milestone with challenges ahead. Drug Safety, 28, 1009-1028. 

With the exception of leurosine, all three alkaloids significantly prolonged the life of animals infected with the PI534 leukemic cell line. This effect was observed even when treatment was delayed until the animals were nearly moribund. However, and perhaps most interestingly, it was observed that cured animals were resistant to additional challenges with this tumor line (i). Sadly, these results could not be extrapolated to clinical situations. 

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