Principles of Chemotherapy Flashcards
LIst Koch’s postulates
- microbe found abundantly in all diseased organisms, but not found in healthy individuals
- microbe isolated from diseased individuals and grown in pure culture
- cultured microbe should cause same disease when inoculated into healthy individual
- must reisolate microbe from inoculated individual and be identified as identical to original pathogen
Is Koch’s first postulate hard and fast
No. You can have the microbe but be healthy(e.g. cholera, typhoid fever)
Is Koch’s third postulate a “must” or a “should”
“Should” because exposure does not mean you will get the infection
What is the term for selective destruction of invading organisms? (Selective means it does not harm the host)
Chemotherapy
Chemotherapeutic design exploits what?
The difference between host and invader.
Does chemotherapy relate how the drug acts on just the disease or how it effects the disease and the host
Just how the drug relates to the disease
What is the goal of selective toxicity?
Administer a substance to produce maximal toxicity to disease-causing organisms, but with minimal toxicity to host.
This is the ratio of the toxic dose/effective dose. This relates everything the medicine does to the patient
Therapeutic Index (TI)
Is selective toxicity the same as therapeutic index?
No. Drug can be selective but have narrow therapeutic index because it is still toxic to host by other modes.
Can very selective compounds fail to produce a cure and why?
Yes. Because they have low therapeutic index.
What are the three parts of the triad of infection?
Host, Drug and Pathogen
What are the ways a drug reacts with host and pathogen in the triad of infection?
Metabolism of drug by host and parasite.
Toxicity of drug to host and parasite.
What 3 general factors for drug-pathogen interaction should be considered when treating?
- Drug resistance of pathogen
- Drug is bacteriostatic
- Drug is bacteriocidal
How do the host and pathogen interact in the triad of infection?
Via the host immune response.
What is the overall goal of the triad of infection?
to illustrate that the interplay of the Host, Drug, and Pathogen determines the outcome
List 6 types of diseases treated by chemotherapy
- Bacterial
- Fungal
- Protozoal
- Helminthic
- Viral
- Cancer
What is the primary problem in treating bacterial infection?
Antibacterial resistance
What characteristic of a fungal infection is important to remember when treating it?
Fungal infections are stubborn and have high recurrence.
What is the more effective treatment for viral infections?
Immunization
Generally speaking, what is the main problem with using chemotherapy to treat cancer?
The difference between tumor and host cells unclear and the cancer drugs have narrow therapeutic index.
What is the concept that substances derived from one living thing may serve to kill other living things?
Antibiotic chemotherapy
What are chemical substances produced by various species of microorganisms (bacteria, fungi) that suppress the growth of other microorganisms or kill other microorganisms?
Antibiotics
Antibiotics can have what two types of effect on bacteria?
- bacteriostatic
2. bacteriocidal
What was first antibiotic: Penicillin or Sulfanilamide?
Sulfanilamide (1936)
What is the most effective group of anti-infectives?
Penicillins
What are the 2 ways to classify chemotherapeutics?
- Mechanism of Action
2. Bacteriostatic vs Bacteriocidal
What are 5 mechanisms of action for chemotherapeutics?
- Inhibit cell wall synthesis
- Act directly on cell membrane
- Affect bacterial ribosome function
- Affect nucleic acid synthesis
- Block metabolic steps
What will happen to a bacterial cell wall if its bacterial cell wall synthesis is inhibited?
Cell lysis
Agents that act directly on the bacterial cell membrane will do what?
Affect bacterial cell permeability causing leakage of intracellular constituents.
If the bacterial ribosome function is affected by chemotherapy, what is inhibited in the bacteria?
protein synthesis