Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MVST1B MODA > Chemotherapy L4 > Flashcards

Chemotherapy L4 Flashcards

1
Q

amantadine is used to treat what?

A

Flu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what does amatadine act on?

A

M2 proton channel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

role of NA in flu?

A

The neuraminidase helps prevent viral aggregation, facilitates release from the host cells, and may have a role as a virulence factor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Two major drugs used against Influenza A are ,…..

A

Two major drugs used against Influenza A are amantadine and rimantadine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how do amantadine and rimantadine work?

A

Both drugs possess a dual mechanism of action. At an early step in viral replication, they block the function of the M2 channel protein. At a later stage, they interfere with hemagglutinin processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The neuraminidase (also termed sialidase) of Influenza A and possibly B is inhibited by

A

The neuraminidase (also termed sialidase) of Influenza A and possibly B is inhibited by oseltamivir and zanamivir;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how do oseltamivir and zanamivir wokr?

A

inhibit neuraminidase

enhance viral aggregation and inhibit release from the host cells. In addition, they reduce movement of the virus particles through the upper respiratory tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Zanamivir is an _____ drug whereas oseltamivir is an ethyl ester ____-drug, which is cleaved by esterases in the plasma and in cells of the gut upon the adsorption of oseltamivir.

A

Zanamivir is an active drug whereas oseltamivir is an ethyl ester pro-drug, which is cleaved by esterases in the plasma and in cells of the gut upon the adsorption of oseltamivir.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how does Ribavirin work?

A
  • taken up as guanosine analogue.
  • phosphorylated by cellular kinases to Ribavirin-MP, DP, and TP.
  • Ribavirin-MP causes a decrease in intracellular [GTP] due to inhibition of inosine monophosphate dehydrogenase -> inhibition of GTP biosynthesis, and ultimately of DNA/RNA synthesis.
  • Ribavirin-TP inhibits dGTP-dependent 5’-cap formation on mRNA.
  • Ribavirin-TP inhibits Influenza RNA polymerase, and hence, inhibits initiation
  • and elongation of viral mRNA synthesis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

bad efects of ribavirin

A

Drug is teratogenic and causes hemolytic anemia in up to 10% of patients due to drug accumulation in erythrocytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how do Zanamivir/Oseltamivir inhibit neuraminidase

A

competitively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

All available anti-herpesvirus agents target the…..

A

All available anti-herpesvirus agents target the virally encoded DNA polymerases that replicate the double-stranded DNA genome of these viruses.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

t or F

Viral DNA polymerases operate in the same manner as cellular DNA polymerases

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how does Aciclovir work?

whats it used to treat?

A

Herpes simplex and Herpes zoster

purine analogue

Aciclovir triphosphate competitively inhibits viral DNA polymerase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why is aciclovir selective against virally infected cells

A

• Aciclovir (=prodrug) is only monophosphorylated by the viral thymidine kinase

  • Viral thymidine kinase is only expressed in infected cells
  • Aciclovir-TP preferentially interacts with the viral DNA polymerase (30 x more potent with viral enzyme)

• Acts as competitive substrate and is incorporated in viral DNA, causing termination of DNA replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

aciclovir is administers?

A

The drug is used topically, orally and i.v.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Ganciclovir and penciclovir are also competitive inhibitors of DNA polymerase, but …

A

Ganciclovir and penciclovir are also competitive inhibitors of DNA polymerase, but they have 3’-OH moieties and will permit chain extension.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

will Ganciclovir and penciclovir permit chain extension?

(theyre antiherpes drugs - purine alalogues)

A

Ganciclovir and penciclovir are also competitive inhibitors of DNA polymerase, but they have 3’-OH moieties and will permit chain extension.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Ganciclovir is more effective that aciclovir against ….

A

Ganciclovir is more effective that aciclovir against CMV-infected cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Pyrimidine analogues - give an example

A

Cidofovir

22
Q

describe Cidofovir

A

Cidofovir is a nucleoside phosphonate analogue of cytosine, which is converted to a diphosphoryl derivative that selectively inhibits the DNA polymerase of CMV

23
Q

Foscarnet is an analogue of what?

A
  • Organic analogue of pyrophosphate
  • Binds selectively to viral DNA polymerase, does not require intracellular metabolism
  • Prevents cleavage of PPi from NTP during DNA synthesis
    *
24
Q

when is foscarnet used?

A

Is used when aciclovir resistance occurs

25
Q

problems with foscarnet

A

Nephrotoxic, proteinuria

26
Q

how is foscarnet administered?

A

i.v. administration required

27
Q

How does Enfuvirtide (Fuzeon) inhibit viral entry into host cells?

A

This drug blocks the conformational change of the HIV envelope spike required to expose the fusogenic domain of gp41.

The virus cannot fuse with the host cell membrane and thus cannot enter the cell.

blocks viral entrty to the cell

28
Q

2 classes of reverse trancriptase inhibitors?

A

non nucleoside and nucleoside

29
Q

how do Non-nucleoside reverse transcriptase inhibitors (NNRTI) work?

give an exmaple

A

Non-nucleoside reverse transcriptase inhibitors (NNRTI), such as nevirapine, bind to the target enzyme near the catalytic site and denature it.

30
Q

how do Nucleoside reverse transcriptase inhibitors (NRTI) work?

A

Nucleoside reverse transcriptase inhibitors (NRTI), such as zidovudine (azidothymidine, AZT) bind to the target enzyme by mimicking naturally occurring nucleosides.

NRTIs (but not NNRTIs) must be phosphorylated by host cell enzymes before becoming active.

They inhibit HIV reverse transcriptase but are also substrates

31
Q

AZT is a ______ analogue.

A

AZT is a thymidine analogue.

32
Q

When incorporated into DNA, NRTIs terminate synthesis because t…..

A

When incorporated into DNA, NRTIs terminate synthesis because these compounds lack 3’-OH groups.

33
Q

Reverse transcription is an early event in the replication cycle, what does this mean about the action of zidovudine and AZT

A

these agents have no effect on a cell in later stages of viral infection.

34
Q

how to incfreae AZT bioavailability

A

Valyl ester of AZT increases bioavailability

35
Q

label

AZT and thmidine

A
36
Q

Hydroxyurea is often co-administered with pyrimidine analogues (such as AZT)

why?

A

Hydroxyurea is often co-administered with pyrimidine analogues (such as AZT) to inhibit ribonucleotide reductase.

This decreases the intracellular pool of pyrimidine nucleotides, and thereby potentiates the effect of pyrimidine analogues.

37
Q

There are currently six protease inhibitors (HIV treatment)

what are they

A
  1. Saquinavir
  2. Indinavir
  3. Amprenavir
  4. Lopinavir
  5. Nelfinavir
  6. Fitonavir
38
Q

which HIv protesase do the 6 protease inhibitors target?

A

aspartic protease

used to cleave the polypeptides

this protease does not occur in the host

Without these cleavages, the newly produced virus is not infectious.

39
Q

HIV protease contains ____ aspartyl residues in its active site

A

HIV protease contains two aspartyl residues in its active site

40
Q

Interferons are….

A

Interferons are cytokine proteins that bind to receptor on the cell surface

41
Q

interferons are synthesized in response to?

A

viral infection and cause biochemical changes that inhibit viral propagation (referred to as “viral interference”

42
Q

There are three classes of interferons:

what are they

A

IFN-a, IFN-b, and IFN-gamma.

43
Q

which interferons have antiviral activity

A

alpha beta

44
Q

which interferones have anti tumour activity?

A

interferon alpha

45
Q

interferons bind to ….what?

A

hey bind to specific ganglioside receptors on host cell membranes and promote in host cell ribosomes the production of enzymes that inhibit the translation of viral mRNA

46
Q

IFN-a-2a is used in the treatment of…..

A

IFN-a-2a is used in the treatment of hepatitis B infections and AIDS related Kaposi sarcomas

47
Q

T or f

People infected with human immunodeficiency virus (HIV) — the virus that causes AIDS — have the highest risk of Kaposi’s sarcoma.

A

T

48
Q

IFN-a-2b is used for treatment of …

A

IFN-a-2b is used for hepatitis C.

49
Q

T ir F

Interferons also activate immune cells, such as macrophages, T lymphocytes and natural killer cells

A

T

50
Q

α and β interferons are produced by all cells in response to ….

A

α and β interferons are produced by all cells in response to viral infections

51
Q

γ interferons are produced only by ,….

A

γ interferons are produced only by T lymphocytes and natural killer cells in response to cytokines

52
Q

fat

A

mamba

MVST1B MODA (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions