Question

hemotherapeutic agents are lacking for many viral diseases.  From what you know about the stages of virus multiplication, give an explanation of why this is so.  Be sure to address each of the stages of viral replication in the discussion.  Also, give an example of an FDA approved treatment for HIV (causative agent for AIDS) and describe the MOA for the treatment.  Be sure to discuss the MOA at the molecular level (i.e. Don’t just say that it blocks attachment.  Explain how at the molecular level.).
Describe in detail the tests would you perform to decide whether a chemical agent could be used as an antiseptic?  As a disinfectant?  Some chemical can serve both purposes.  Describe the properties of such a chemical and give an example.

chemotherapeutic*

the first word of the question is chemotherapeutic not hemotherapeutic

Answer 1

Viral infection involves incorporating the viral DNA into the host cells. This viral DNA is replicated so that new viruses are released to infect the other host cells.
  
Viral replication involves 6 steps: Attachment , penetration, uncoating, replication, assembly and release.

The viral replication cycle can induce a dramatic biochemical or structural changes in host cells, which damages the host cells. These changes are called as cytopathic changes which can change cell function or destroy them.

1. Attachment : A virus attaches to a specific receptor site on the host cell membrane through attachment proteins in the capsid.
2. Entry : The Nucleic acid of the virus enters the cells leaving behind the capsid. Plant and animal virus enter through endocytosis where the cell membrane surrounds and engulf the entire virus, in such cases once the virus enters the cells , the capsid is degraded and the viral nucleic acid is released and becomes available for replication and transcription.
3. Replication and Assembly : DNA viruses use host cells proteins and enzymes to make DNA that is transcribed to mRNA which is then used to direct protein synthesis. RNA viruses use RNA core as a template for synthesis of viral genome RNA and mRNA.
4. Egress: the last stage of replication is where the new virons produced in the host organism is released so that they infect the adjacent cells and repeat the replication cycle.

It is difficult to find a good chemotherpeutic agent for viruses because
There is no effective way to deliver the drug to the virus. Because viruses infect both bacteria and human cells and it depends on the host cells machinery it is hard to find a viral target that would leave the host cells unaffected.
Specificity against virus repliaction is the main issue for chemotherapeutic agents.
although few anti viral drugs are developed they show a narrow antiviral spectrum, ineffective against latent virus, development of drug resistant mutants and toxic side effects.

B. There are several FDA approved drugs for HIV treatment. Such as Protease inhibitor : atazanavir, darunavir, ritonavir. Non nucleoside reverse transcriptase inhibitors ( NNRTI's) bind and alter reverse transcriptase needs for hIV to make copies of its self. These include : doravirine, etravirine, nevirapine.
Let us consider mechanism of action of one drug amongst all of these.
1. Atazanavir binds to the active site of the HIV protease and thus preventing it from cleaving the pro-form of viral proteins into the working machinery. which means if the protease enzyme dont work the virus reamains not infectious and no mature virons are made and thus the infection is under control.
atazanavir is a structural analog of the transition state during which bond between a phenlyalanine and proline is broken. it does not affect the human cells becauase humans do not have enzyme that break bonds between a phenlyalanine and proline.

C. Antiseptics kill microbes and these are applied to the body. Both antiseptic and disinfectant has a chemical agents that are sometimes called as biocides. Hydrogen peroxide is an example of a common ingredient in both of antiseptics and disinfectant. however, antiseptics contain low concentration of biocides than disinfectants.
Chlorohexidine and other biguanides, peroxide and permanganate are few of the antiseptics.

Disinfectants are antimicrobial agents designed to destroy or inactivate microbes on inert surfaces. Disinfection need not mean killing all microbes especially resistant bacterial spores.