Details Title: 15.Medical Micro - HIV Description: Finished Total Flash Cards: 35 Created: 12/15/2008 10:38:06		New Users: To study from this flashcard set, or to create your own your own study flash cards, REGISTER HERE. Existing Users: CLICK HERE. Additional Biology Flashcards
Cards in this set: Term Retroviridae Definition group of RNA viruses that infect animals and humans   "Retro, Grow and Blow"   Retro -  carry reverse transcriptase to convert viral RNA into DNA -Sticky ends allow it to integrate into the host's DNA   Grow - cause normal cells to become malignant due to oncogenes   Blow -are cytotoxic to certain cells and destroy them (like HIV to t helper lymphocytes)   Term Proto-oncogenes Definition inactive oncogenes present in humans and animals that are normally present.   Essentially are time bombs awaiting activation from carcinogen-induced DNA mutation or retrovirus infection. Term Cancer Definition -loss of contact inhibition between cells which causes mass pile-ups of malignant cells Term HIV Definition Human Immunodeficiency Virus   dimer of two ssRNA pieces   has a surrounding RNA dimer with a capside sheel made up of capside protins (p24 is major one) Term 3 essential retroviral enzymes present in HIV Definition integrase reverse transcriptase protease Term HIV Genome sequence Definition Two ending long terminal repeat (LTR) sequences gag gene pol gen env gene     LTR - GAG - POL - EVN - LTR   same in all retroviruses (I think) Term Functions of LTR Definition act as sticky ends - that are recognized by intergrase and inserted into the host DNA   also modifies viral DNA transcription Term Functions of GAG genes Definition sequences code for proteins inside the evelope   these include:   nucleocapsid protein p24 protein matrix protein Term POL genes Definition encode sequences for enzymes   these include:   integrase, reverse transcriptase and protease   these enzymes are needed to cause disease Term ENV genes Definition codes for the envelope proteins Term Regulatory proteins Definition are encoded by regulatory genes known as:   tat, rev or nef genes Term acute transforming retrovirus Definition these carry intact oncogenes integrate into host DNA and cause Malignancies Term Non-acute transforming retrovirus Definition activate host cell proto-oncogenes by integrating viral DNA into a key regulatory area   -often have a full genome for viral replication Term three important enzymes for HIV reproduction, etc Definition integrase, reverse transcriptase, protease Term HIV Stats Definition 44 million infected (90% in developing countries) 14 million dead Term HIV epidemiology Definition Western world - homosexuals and IV users  therefore, more men infected then women   Developing world - equal male:female infection ratio  because it is spread via sexual activity Term HIV Cell infection Definition HIV virion enters blood stream and it's gp160 glycoprotein binds to CD4 receptors on target cells     Term Cells targeted by HIV Definition -cells that have CD4 receptors   include T-helper lymphocytes, macrophages, monocytes and dendritic cells (in CNS) Term Corecptors that aid in the attachment of HIV to host cell Definition CCR5or CXCR4   Therefore, patients who lack normal CCR5 are resistant to HIV Term HIV once in the cytoplasm Definition in the cytoplasm, viral RNA is reverse transcriped into DNA   -dsDNA taken to nucleus -integrase used to integrate it into host DNA Term Outcomes of integrated DNA Definition a. remains inactive (latent)   b.are cleaved by HIV proteases and assembled into new virions Term HIV and T-cell counts Definition Healthy person - 1000 T helper cells/mL of blood   HIV causes a decline of about 60 T cells/mL per year   7 years - 400-200/mL 8 years - <200/mL (constitutional symptoms)   Term T cell count less than 200/mL Definition results in Serious opportunistic killers   opportunistic cillers such as Pneumocystis carinii pneumonia, crytococcus neoformans and toxoplasma gondii move ie. Term T cell count less than 60/mL Definition Immune system is completely down   get cytomegalovirus infection and mycobacterium avium - intracellulare Term Significance of T cell death Definition -normally recruit macrophages, neutrophils and B-lymphocytes   -w/o B-lymphocytes - reduces ability to produce                             antibodies   Multinucleated giant cells formed by T-cell fusion:          this allows viruses to pass between infected          cells without having to contact antibodies.                       Term Cells that can serve as reservoirs of HIV Definition monocytes and macrophages   this is b/c HIV does not destroy these cells Term Two initial outcomes of HIV infection Definition 1. immediate viral replication.  Acute illness     2. Virus replicates slowly (latency).  Chronic illness        Term Acute Illness due to HIV Definition Symptoms include   -fever, lymphadenopathy, pharyngitis....       -virus spreads to lymph nodes and macrophages Term Chronic Illness due to HIV Definition -Often follows initial acute illness   -HIV replicates in lymphoid tissue -steady destruction of CD4 - T - Lymphocytes     Symptoms: fever, weight loss, night sweats...   Overall, a weakened immune system leading to AIDS Term Formal Definition of AIDS Definition -A CD4 count less than 200 Term Two types of 'diseases' caused by AIDS Definition 1. Direct viral disease: fever like symptoms, weight loss, neurological disease (which affects cognitive function, etc).   2. Secondary Diseases: diseases caused as a result of the immune deficient state.   eg. opportunistic pathogen infections, malignancies. Term Common Malignancies seen due to diseases secondary to immune deficiency state Definition B-cell lymphomas (present as a brain mass)   Kaposi's sarcoma - red to purple nodules Term Opportunistic infections common to AIDS patients Definition Bacterial - S. aureus, S. epidermidis, H. influenza and                S. pneumoniae   Fungal - candida albicans, cryptococcus neoformans   Viral -herpes Zoster and Simplex, Epstein Barr Virus          and cytomegalovirus   Protozoal - Pneumocystis carinii (fungus?),                  toxoplasma gondii Term Most common opportunistic pathogen in AIDS Definition Pneumocystis carinii   causes cough and hypoxia, fine reticular opacification Term AIDS Diagnosis Definition ELISA test - detects antibodies CD4 T-helper counts (if less than 200) Viral RNA antigens