Question

(Case 7) "THE HIV" Aja is a 24-year-old seeking prenatal care as she is one month pregnant with her first child. Her prenatal HIV antibody screen results positive for Human Immunodeficiency Virus-1. Aja reveals that she has a history of multiple sexual partners and no former antiviral therapy. Aja's bloodwork shows that her CD4 helper T-cell lymphocyte levels are normal, however, treatment with the antiviral drug AZT (also known as Zidovudine) is prescribed to aid in prevention of passing the virus from Aja to her baby. 1. HIV is known as a retrovirus with an RNA genome. This virus uses which core enzyme to convert its RNA to a DNA copy? Hint: this is a review question from unit 1. (1p) 2. AZT is an antiretroviral drug which acts as a nucleoside analog ("fake" or mimics thymidine found in our DNA). The enzyme in question 1 will attempt to make a DNA copy of the viral RNA. Research and explain how AZT interferes with that process of converting RNA DNA. (2pts) 3. Which specific step (of the 6 steps of viral replication) are inhibited by this drug? (1p) Hint: You may have to refer to the Antimicrobial drug PowerPoint and the Unit 1 Virology PowerPoint for help. 4. AZT may have a variety of side effects. Explain why antiviral drugs are typically more toxic to a human patient than say a natural antibiotic. (pts) 5. AZT does not cure an HIV infection. Why are there currently no mainstream cures for HIV? Hints: Think about what HIV does with its DNA copy (where does it go in our cells?). Do antivirals "kill" viruses? (2pts)

Answer 1

1) RT ( reverse transcriptase) enzyme involve in conversion of RNA in to DNA.

2) AZT drug aftrr enter in to cell , converted in to AZT tri phosphate and enter in to DNA and inhibit reverse transcriptase enzyme.

Thus prevent conversion of RNA to DNA.

3) in viral replication among all the steps, step 3 which involves conversion of RNA to DNA by reverse transcriptase is inhibited by AZT.

4) Antiviral drug play an important role in protection against viral diseases. But long-term usehas been associated with adverse effects mainly associated with mitochondrial dysfunction or toxicity and the inhibition of mitochondrial DNA synthesis. After transformed into their active 5′-triphosphate forms serve as alternative substrates for HIV-1 reverse transcriptase (RT). Also the same 5′-triphosphate forms of nucleoside analogs used by mitochondrial polymerase γ, and incorporated in to mitochondrial DNA which leads to termination of DNA synthesis and leads to mitochondrial dysfunction.

5) there is no cure for HIV because this drug do not kill the virus but it prevents formation of new virus by inhibiting RT thus by restricting no of virus it prolonged life of patients.