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Re evaluating the Categorization of HIV Progression in Subjects Based on CD4 T cell Decline Rates Angela Garibaldi & Ryan Willhite Loyola Marymount University BIOL 398-01/S10 March 2, 2010 Angela Garibaldi & Ryan Willhite Loyola Marymount University BIOL 398-01/S10 March 2, 2010
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Outline Review of the Markham method of labeling compared with CD4 T cell decline rate categorization of progressors. Selection Process Prediction Statistical Approach Results Discussion/ Comparison to More Recent Studies References Review of the Markham method of labeling compared with CD4 T cell decline rate categorization of progressors. Selection Process Prediction Statistical Approach Results Discussion/ Comparison to More Recent Studies References
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Categorizing Progressors by CD4 T cell Count Patterns of HIV-1 evolution in individuals with differing rates if CD4 T cell decline Rapid Progressors Fewer than 200 CD4 T cells, within 2 years of seroconversion Moderate Progressors CD4 T cell levels 200-650 during 4 year period Non-progressors CD4 T cell levels above 650 Patterns of HIV-1 evolution in individuals with differing rates if CD4 T cell decline Rapid Progressors Fewer than 200 CD4 T cells, within 2 years of seroconversion Moderate Progressors CD4 T cell levels 200-650 during 4 year period Non-progressors CD4 T cell levels above 650
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Selecting Subjects to Analyze
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Selecting Subject Clones Selected the most recent visits that had sequenced clones. (Many had 0 clones for last 3+ visits) Utilized only “Distinct Sequences” Selected the most recent visits that had sequenced clones. (Many had 0 clones for last 3+ visits) Utilized only “Distinct Sequences”
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What we predict… Subj. 6 (Moderate Test) and 13 (Non-Progressor) will be less divergent and have less diversity than when 6 is compared to another Moderate (5,7) Subj. 7 (Moderate Test) and 10 (Rapid- Progressor) will be less divergent and have less diversity than when 7 is compared to another Moderate (5,6) Subj. 6 and 7 will be more divergent and have higher diversity in comparison to values generated in the above. Subj. 6 (Moderate Test) and 13 (Non-Progressor) will be less divergent and have less diversity than when 6 is compared to another Moderate (5,7) Subj. 7 (Moderate Test) and 10 (Rapid- Progressor) will be less divergent and have less diversity than when 7 is compared to another Moderate (5,6) Subj. 6 and 7 will be more divergent and have higher diversity in comparison to values generated in the above.
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Statistical Approach Utilized BedRock Conduct Clustdist multiple sequence alignment for comparison and frequency values used to : Calculate ''S'' ''Theta” to measure Divergence ''Minimum'' and ''Maximum” S/Number of clones to interpret Diversity Utilized BedRock Conduct Clustdist multiple sequence alignment for comparison and frequency values used to : Calculate ''S'' ''Theta” to measure Divergence ''Minimum'' and ''Maximum” S/Number of clones to interpret Diversity
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Results SubjectNumber of Clones SThetaMin difference Max difference Range 6 vs 13539320.48385012 7 vs 10629620.43274215 6 vs 7539320.48264115 6 vs 5499020.18234219 7 vs 5488318.69344915 10 vs 55910322.15304812 13 vs 5437918.22344612
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Divergence Min. and Max. values show that 6 and 10 are most divergent Considers Frequencies Min. and Max. values show that 6 and 10 are most divergent Considers Frequencies
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Divergence using Theta Values
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Diversity shows a clearer picture Diversity similarities between (6,5) & (13,5)
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Revisiting the Results Divergence does not prove to be an accurate method of categorizing Theta did not deliver insight Diversity levels are similar in certain categories Divergence does not prove to be an accurate method of categorizing Theta did not deliver insight Diversity levels are similar in certain categories
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Implications of using CD4 Tcell Decline Rate to Categorize This method is Better than Markham’s method of categorization Especially in categorizing moderates from rapids Not as successful without a larger sample size Not much success in comparing all In the future Find a way to calculate the significance A larger sample size Use a program that would allow a comparison with higher number of clones Few clones available from subjects may complicate the reliability. Focus on most recent visits and acquire clones for these visits This method is Better than Markham’s method of categorization Especially in categorizing moderates from rapids Not as successful without a larger sample size Not much success in comparing all In the future Find a way to calculate the significance A larger sample size Use a program that would allow a comparison with higher number of clones Few clones available from subjects may complicate the reliability. Focus on most recent visits and acquire clones for these visits
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More Recent Study Nucleotide and amino acid mutations in human immunodeficiency virus corresponding to CD4+ decline M. D. Hill and W. Hern´andez Ponce School of Medicine, Ponce, Puerto Rico Published online January 3, 2006 _c Springer-Verlag 2006 Nucleotide and amino acid mutations in human immunodeficiency virus corresponding to CD4+ decline M. D. Hill and W. Hern´andez Ponce School of Medicine, Ponce, Puerto Rico Published online January 3, 2006 _c Springer-Verlag 2006
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Comparing our findings to more recent studies Change in diversity of nucleotide sequences among HIV forms within individuals as their CD4+ counts progressed There is a trend for the average distance to increase with dropping CD4+ values Among all progressors, 94.1% of subjects demonstrated increased diversity The rapid progressors had a statistically significant higher loop charge Four of the rapid progressors had T-tropism Change in diversity of nucleotide sequences among HIV forms within individuals as their CD4+ counts progressed There is a trend for the average distance to increase with dropping CD4+ values Among all progressors, 94.1% of subjects demonstrated increased diversity The rapid progressors had a statistically significant higher loop charge Four of the rapid progressors had T-tropism
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How Does this Compare?… Found that progression is easier to evaluate than non-progression in terms of diversity The moderate and rapid progressor were most divergent Therefore there is an accumulation of differences over a period of time Perhaps there needs to be further investigation in: RNA and DNA sequences A closer look at regions described in paper such as loop charge Found that progression is easier to evaluate than non-progression in terms of diversity The moderate and rapid progressor were most divergent Therefore there is an accumulation of differences over a period of time Perhaps there needs to be further investigation in: RNA and DNA sequences A closer look at regions described in paper such as loop charge
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References Markham RB, Wang WC, Weisstein AE, Wang Z, Munoz A, Templeton A, Margolick J, Vlahov D, Quinn T, Farzadegan H, and Yu XF. Patterns of HIV-1 evolution in individuals with differing rates of CD4 T cell decline. Proc Natl Acad Sci U S A 1998 Oct 13; 95(21) 12568-73. pmid:9770526. Hill MD and Hern � ndez W. Nucleotide and amino acid mutations in human immunodeficiency virus corresponding to CD4+ decline. Arch Virol 2006 Jun; 151(6) 1149-58. doi:10.1007/s00705-005-0693-8 pmid:16385396. PubMed HubMed PubGet [Paper1] HIV project handout for statistical analysis info Markham RB, Wang WC, Weisstein AE, Wang Z, Munoz A, Templeton A, Margolick J, Vlahov D, Quinn T, Farzadegan H, and Yu XF. Patterns of HIV-1 evolution in individuals with differing rates of CD4 T cell decline. Proc Natl Acad Sci U S A 1998 Oct 13; 95(21) 12568-73. pmid:9770526. Hill MD and Hern � ndez W. Nucleotide and amino acid mutations in human immunodeficiency virus corresponding to CD4+ decline. Arch Virol 2006 Jun; 151(6) 1149-58. doi:10.1007/s00705-005-0693-8 pmid:16385396. PubMed HubMed PubGet [Paper1] HIV project handout for statistical analysis info
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