1. WE’RE BACK...

2. Altering HIV Treatment to Maximize Life Span Denise Tabasco Emma Benn Rachel Epstein Audrey Hucks

3. The Big Question When is the best time to treat HIV so that the infected person will have a maximum lifespan?

4. Two Key Issues of Treatment Strategy  Time of Initiation of Treatment  Time at which drug resistant virus appears

5. Methods   We need to learn about and research the various treatments for HIV – –how each works – –effects of each – –known information about resistance to each – –studies done on each   We’ll use the model to experiment with different values and times of initiation of We need to learn the basics of HIV/AIDS   treatment   We’ll find studies/experiments done which illustrate different treatment initiation

6. Equipment   Maple/Java run programs graph experiment use as visual displays of information   Netscape ( to search for information) general information on HIV treatments studies Medscape

7. MODEL WITHOUT TREATMENT n 1. n 2. n 3.

8. Model With Treatment W 4. W 5. W 6. W 7. W 8.

9. OH NO!!! There’s a problem with the Kirschner/Webb model!!! Doh!

10. When we reproduced the graphs...

12. Here’s what worked:  Apparently, there was a typo in one of the most sensitive parameters, p (the proliferation rate of uninfected CD4+ T cells) so rather than p equaling 0.5, it should be 0.05

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16. Nowak Model A ( )

17. References   Herod, James V., Shonkwiler, Ronald W., and Yeargers, Edward K. An Introduction to the Mathematics of Biology: with computer algebra models Birkhauser Boston, Boston, 1996.   HIV and AIDS: Martin A. Nowak and Andrew J. McMichael, “How HIV Defeats the Immune System,” in Scientific American, Vol. 273, No. 2, page 58, August 1995.   HIV and T cells: A. S. Perelson, D. E. Kirschner and R. J. De Boer, “The Dynamics of HIV infection of CD4+ T Cells,” Math. Biosci. 114, pp. 81-125, 1993.   Kirschner, D. E. and Perelson, A. S. “A Model for the Immune System Response to HIV: AZT Treatment Studies.”   Kirschner, D. E. and Webb, G. F. “A Mathematical Model of Combined Drug Therapy of HIV Infection.” Journal of Theoretical Medicine, Vol. 1, pp. 25-34, 1997.

18. Thanks for you attention and... Have a nice day!