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HIV & AIDS in the United States AIDS deaths in the U.S. decreased by 42% from 1996 - 97 >1,000,000 Men, Women & Children were living with HIV in 2004.

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Presentation on theme: "HIV & AIDS in the United States AIDS deaths in the U.S. decreased by 42% from 1996 - 97 >1,000,000 Men, Women & Children were living with HIV in 2004."— Presentation transcript:

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2 HIV & AIDS in the United States AIDS deaths in the U.S. decreased by 42% from 1996 - 97 >1,000,000 Men, Women & Children were living with HIV in 2004 >45,000 new infections in 2004 Women accounted for >30% of new HIV diagnoses in adults

3 U.S. HIV & AIDS by Race/Ethnicity since 1999 Among new AIDS cases in men, 61% were in African Americans and Hispanics Among new AIDS cases in women, 80% were in African Americans and Hispanics AIDS is now the #1 killer of African American women age 25 - 34 HIV incidence among African Americans is now 8 times higher than among Caucasians

4 HIV infection is more common than previously thought >40 million now HIV infected  5 million infected in 2004 @ a rate of ~14,000/day ~ 2000 in children <15 y.o. ~ 12,000 in persons 15 - 49 y.o. (50% women; 50% 15 - 24 y.o.)  1% of sexually active adults are infected  90% of the infected don't know it!  >3 million died from AIDS in 2004 - 60% more than in 1996  >33% were Adult women  ~20% were under 15 years old U.S. versus GLOBAL HIV NUMBERS

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6  8% of 15-49 years old are infected  In Botswana, Zimbabwe, Nigeria, Swaziland 25 - 30% of adults are infected  In large towns of Zimbabwe ~70% of pregnant women are infected In Sub-Saharan Africa:

7 Causes of deaths, globally and in Africa 4.2 2.8 2.3 19 2.2 0.3 0 2 4 6 8 10 12 14 16 18 20 HIV/AIDSTuberculosisLung cancer Percent of deaths Global Africa

8 Projected changes in life expectancy in selected African countries with high HIV prevalence, 1995–2000 Source: United Nations Population Division, 1996 1955196019651970197519801985199019952000 Average life expectancy at birth, in years 65 60 55 50 45 40 35 Zimbabwe Zambia Uganda Botswana Malawi

9 HIV prevalence rate among teenagers in Kisumu, Kenya, by age 00 3.6 2.2 8.6 8.3 17.9 29.4 22 33.3 0 5 10 15 20 25 30 35 1516171819 Age in years HIV prevalence (%) boys girls Source: National AIDS Programme, Kenya, and Population Council, 1999

10 despite the most concerted effort of medical research in modern history. e.g. - Exclusive CD4 cell tropism - Idea of viral dormancy etc. - Combination therapy Much of what we took for granted has been proven wrong...

11 CO-OPTION AND DESTRUCTION OF THE IMMUNE SYSTEM BY HIV

12 OVERVIEW OF THE HIV LIFECYCLE

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14 CLINICAL COURSE OF HIV INFECTION

15 Surprising finding of very high rates of HIV replication & CD4 cell turnover in HIV+ patients Current estimates of 100 billion new HIV particles / day 1 - 2 billion CD4 cells are killed and regenerated / day Dynamics of CD4 cell Numbers during HIV Disease

16 CD4 - cells can be infected by HIV e.g.: Bowel/Renal epithelia ALTERNATIVE RECEPTORS FOR HIV (CD4-INDEPENDENT)

17 A glycolipid may cluster with other glycolipids  Form lipid rafts + CD4  HIV infects cultured neuronal cell lines  anti-GalC Abs block in both CD4 - cell lines  some accumulation on surface (1) GalC - Galactosyl ceramide

18 Formation of chimeric viruses where one viral genome can be encapsulated within a different viral envelope - created in vitro by co-infection with two viruses HIV pseudotypes observed include:  HIV-1 + HIV-2  HIV-1 + HTLV-I  HIV + murine retroviruses  HIV + herpes viruses e.g. HSV (2) Pseudotype Viruses in HIV Infection HIVHSV CELL pseudotypes

19 Primarily via changes in the cell membrane (a) Auto Fusion Evidence for a loss in osmotic balance  decrease in intracellular ionic strength  results in cell ballooning and lysis DIRECT TOXIC EFFECTS OF HIV PROTEINS (b) Cultured brain cells exposed to gp120 show an influx of Ca 2+  overactivation of Ca 2+ Kinases etc.  Reversed by nimodipine - Ca channel antagonist gp120/41 CD4

20 The FasL/Fas (CD95) ligand/receptor complex helps maintain lymphocyte homeostasis via cell depletion HIV-induced Apoptosis via Fas Receptor

21 Fas/FasL Mechanism of Action CAD (caspase-activatable DNase)

22  Have a higher degree of activation  Have  Fas expression on their surface  Are more sensitive to FasL induction of apoptosis HIV infection of macrophages/monocytes increases the production of FasL  Uninfected T-cells undergo apoptosis when cocultured (Contact necessary) Observation: uninfected T-cells from HIV+ Patients

23  Human APCs, macrophages can produce FasL and are upregulated when HIV infected  This elevated level of FasL expression can induce apoptosis in uninfected T-cells (by contact) IN THE CENTRAL NERVOUS SYSTEM  soluble FasL also detected in cerebrospinal fluid (CSF) samples from HIV-infected patients  may contribute to brain injury with progression to AIDS  specifically targets astrocytes and glial cells


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