Principles of Chemotherapy Flashcards

1
Q

what underlies immunity

A

the body’s ability to recognise and remove non-self material

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2
Q

what underlies the action of anti-microbial drugs

A

ability of drugs tp recognise and destroy non-self cells

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3
Q

what principle is chemotherapy based off

A

selective toxicity

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4
Q

selective toxicity

A

drugs directed against targets that are involved in the function of abnormal cell/invading organism but aren’t required for host function

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5
Q

chemotherapeutic index

A

lowest dose toxic to patient divided by the dose typically used for therapy

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6
Q

different types of antimicrobial drugs

A

antibacterial drugs
anti fungal drugs
anti protozoan drugs
antihelminthic drugs

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7
Q

antimicrobial drug

A

drug used to control bacteria, fungus, parasites, etc

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8
Q

why are bacteria useful targets

A

because drugs show selectivity for isoforms

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9
Q

trimethoprim chemistry

A

MW 290

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10
Q

trimethorprim pharmacology

A

primary activity is via inhibition of dihydrofolate reductase
interaction between enzyme and substrate is via hydrogen bonding and antibiotic is a structural analogue of the substrate DHF

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11
Q

trimethoprim physiology

A

dihydrofolate reductase DHFR is an essential enzyme
catalyses the reduction of dihydrofolate acid
to tetrahydrofolic acid
role of DHFR is related to the biosynthesis pathways of thymidylate and purines
inhibition leads to disruption of DNA replication
causes cell death

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12
Q

trimethoprim clinical

A

often used in conjunction with sulfamethoxazole
treat infections: urinary, respiratory,ghastrointestinal tracts
also treat malaria and has anti proliferative effects (cancer)

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13
Q

class 3 reactions

A

many are targets for selective toxicity

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14
Q

what are class 3 reactions

A

pathways that convert small class 2 molecules into macromolecules

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15
Q

what are class 2 reactions

A

pathways that utilise ATP and class 1 substrates to make small molecules

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16
Q

cell wall synthesis

A

D-cycloserine
vancomycin
bacitracin
pincillins
cephalosporins
ephamycins

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17
Q

cell wall integrity

A

beta-lactamases

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18
Q

DNA synthesis

A

metronidazole

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19
Q

DNA gyros

A

quinolones

20
Q

RNA polymerase

A

rifampicin

21
Q

phospholipid membranes

A

polymyxins

22
Q

two types of protein synthesis

A

50S and 30S

23
Q

30S inhibitors

A

tetracyclins
streptomycin
spectinomycin
kanamycin

24
Q

examples of beta lactam antibiotics

A

penicillins
cephalosporins
monobactams
carbapenems

25
synthesis of cell walls as a target for antibacterial drugs
synthesis of N-acetylmuramic acid-pentapeptide units synthesis of peptidoglycan polymers cross-linking of peptidoglycan chains
26
PBP's
penicillin binding proteins
27
example of a PBP
transpeptidase enzyme that normally catalyses cross-linking of peptidoglycan polymers
28
beta-lactam mechanism of action
structural analogs of D-ala-D-ala covalently bind to PBPs (transpeptidase) leads to inhibition of transpeptidation reaction essential for peptidoglycan synthesis
29
what type of drug is trimethoprim
diaminopyrimidine
30
ligand and target for trimethoprim §
10931 dihydrofolate reductase
31
what type of drug is amoxicillin
beta lactam
32
amoxicillin ligand and target
10865 bacterial penicillin binding protein
33
chemistry of amoxicillin
MW 365
34
pharmacology amoxicillin
primary activity inhibition of transpeptidases (specialised acyl serine transferases) beta lactams mimic the d-ala-d-ala sequence and act as a false substrate for d-alanyl-d-alanine transpeptidases
35
physiology amoxicillin
competitively inhibits penicillin binding proteins leads to up regulation of autolytic enzymes and inhibition of cell wall synthesis causes cell lysis
36
cidal
causes cell lysis
37
clinical amoxicillin
treatment of susceptible bacterial infections in: ear, nose, genitourinary tract, skin, skin structure and lower respiratory tract used with omeprazole to treat helicobacter pylori
38
ribosomal synthesis of proteins
potential target for antibacterial drugs
39
aminoglycosides
targets 30S subunit gentamicin 16 S rRna induces misreading, halt protein synthesis at high concentrations
40
tetracycline
targets 30S subunit 16 S rRNA block aminoayl tRNA binding
41
macrolides
targets 50 S subunit clarithromycin 23 S rRNA inhibits translocation
42
fusidic acid
50S subunit 23 S rRNA inhibits translocation
43
what type of drug is clarithromycin
macrolide
44
chemistry of clarithromycin
MW 748 semisynthetic macrolide derived from erythromycin
45
ligand and target clarithromycin
10903 23S ribosomal RNA
46
pharmacology clarithromycin
reversibly binds to 23S rRNA component of 50S ribosomal subunit of the ribosome inhibits the translocation of aminoayl transfer-RNA prevents peptide chain elongation
47
physiology clarithromycin
inhibition of protein synthesis causes ell death due to cell inability to produce new proteins