antiviral drugs: herpesviruses Flashcards
what is herpes simplex type-1
causes edema, hemorrhages and necrosis near temporal lobes
what is herpes simplex type-2
genital herpes
what is varicella zoster virus
shingles
if this virus replicates it leads to nerve damage
what are the 4 diseases that kaposi’s sarcoma associated herpesvirus causes
1-kaposi’s sarcoma- antiproliferative tumour on skin, lymph nodes and viscera
2-multicentric castleman’s- lymphoproliferative
3-primary effusion lymphoma-aggressive
4-KSHV inflammatory cytokine syndrome- high tumours high morality
what happens in the lytic herpesvirus replication cycle
virus enters host cell
transcription
genome replication
virus assembly
virus envelopment
what happens after lytic infection
enters sensory neuronal axons migrates along to CNS
explain the pathophysiology of genital herpes
vesticular lesions
dormant in sensory ganglion for host life
reactivate travels down to mucosal surface
virus shedding
leads to transmission
what are the treatments for genital herpes
acyclovir-systematic therapy
valacyclovir- oral
famcyclovir-oral
what is acyclovir an analogue of
guanosine
how do these analogues get into the DNA chain
they are phosphorylated
what do these analogues prevent
chain elongation and lead to cell death
what does acyclovir lack
ribose moiety
how is valacyclovir different
esterified version
what is famcyclovir a prodrug of
penciclovir
how do helicase-primase inhibitors acts as antivirals
enhance binding of complex to DNA
prevents viral DNA replication
what is contained in the structure of this complex
DNA helicase
RNA pol
ssDNA stimulated ATPase actvities
which inhibitor prevents growth of acyclovir resistant strains
BILS 179 BS
how is neonatal herpes prevented
woman with established infection has c-section
if no symptoms then acyclovir given for 36 weeks
what does herpes zoster cause
child-chicken pox
elderly-shingles
post herpetic neuralgia -abnormal signals sent to brain which cause pain
what is evident in a patient with post-herpetic neuralgia
few nerve endings
acyclovir shortens virus shedding limits neurone damage
what do the antiviral molecules cidofovir derivatives do
inhibit viral DNA pol
needs 2 phosphorylation=active can be done by cellular kinases
more toxic and side effects
describe the helicase primase inhibitor ASP2151
better than acyclovir
effect on VZV DNA replication
describe the role of bicyclic pyrimidine nucleoside analogues
VZV TK turns BCNA to diphosphate when it is then inserted into viral DNA
how does opioid analgesics treat pain
bind to opioid receptors in brain
release of morphine and oxycodone
can cause drowsiness, cognitive slowing, nausea
how do tricyclic antidepressants work in treating pain
serotonin-norepinephrine reuptake inhibitors
block the transporters
increase concentration of these in cell
enhance neurotransmission
what is zostavax
vaccine
reduces shingles
single dose
boost immunity with individuals with pre existing VZV infection
why is there not treatment for kaposi’s sarcoma
KSHV thymidine kinase cannot phosphorylate acyclovir
what therapies can be used for this disease
highly active retroviral therapy
what does KSHV induce
VEGF pathway
name a VEGF inhibitor
bevacizumab
what is c-Kit
expressed by KS tumour
tyrosine kinase receptor
regulates cell growth, division, migration
give an example of a Kit inhibtor
imatinib
