B6 - Preventing And Treating Disease Flashcards
What can be found inside vaccines
- dead pathogens
- weakened pathogens
- antigens
- toxins
- mRNA mimic
What is the MMR vaccine?
Measles Mumps Rubella vaccine
define herd immunity
Vaccinated people protect the people who are unable to be vaccinated by acting as a barrier to infections.
define antibodies
y-shaped proteins which kill/slow growth of bacteria and fungi.
how do antibodies work?
- disrupting cell functions to stop reproduction
- breaking down cell walls
why do antibodies not affect viruses?
- viruses are intracellular meaning that antibodies cannot affect them when they are inside human cells.
- viruses don’t have the same cellular structures as bacteria or fungi
describe:
development of resistance in bacteria
- random mutations happen in bacteria which produces new strains
- some strains might gain resistance against antibiotics so they don’t die to antibiotics
- resistant bacteria reproduce with less competition because other non-resistant bacteria die from the antibiotics.
- population of the strain rises which is then spread to others
- there is no effective treatment to kill it off
how do vaccines work?
The vaccine stimulates the immune response, leading to memory cell production. If the pathogen re-infects, memory cells produce the correct antibodies that stop the infection. This is called active immunity.
define superbug
bacteria or fungi that are resistant to multiple antibiotics
give an example of a superbug
MRSA
methicillin resistant staphylococcus aureus
how to reduce the rate of development of antibiotic resistant strains
- doctors should not prescribe antibiotics for non-serious or viral infections
- patients should complete the full course of antibiotics so all bacteria are killed and none survive to mutate and form resistant strains
- agricultural use of antibiotics should be restricted
Why is it difficult to keep up with the emergence of new resistant strains?
The development of antibiotics is slow and costly.
Why is it difficult to develop drugs that kill viruses?
The drugs can damage human cells because viruses are intracellular.
3 examples of drugs extracted from natural sources
- heart drug digitalis - foxglove
- painkiller aspirin - willow
- antibiotic penicillin - Penicillium mould
Who discovered penicillin?
Alexander Fleming
5 sources of drugs
- plant sources
- microbiological sources
- synthetic sources (starting point may still be extracted from a plant)
- mineral sources
- animal sources
What happens in the preclinical development of a drug?
The drug is tested on computer models, human cells, and animals. To test if the drug is safe.
What happens in phase 1 clinical development of a drug?
The drug is tested on 50-100 healthy patients. To test if there are any side effects.
What happens in phase 2 clinical development of a drug?
The drug is tested on 200-400 infected patients. To test the optimum dose.
What happens in phase 3 clinical development of a drug?
The drug, an existing drug, and a placebo are tested on 3000+ infected patients. This is to compare the drug to the existing drug and the placebo to see how effective the new drug is. This phase includes doing blind or dobule blind trials.
define blind trial
The patient who takes the drug doesn’t know whether they are given a placebo or the drug.
define double-blind trial
Neither the patient who takes the drug nor the doctor who administers it knows whether they are given a placebo or the drug. This method is used to remove bias.
define placebo
a treatment with no active ingredient
How are monoclonal antibodies produced?
- antigens are injected into an animal to start an immune response
- B-lymphocytes, which produce antibodies, are extracted from the animal
- Myeloma cells, which have a high reproduction rate, are fused with the B-lymphocytes to form hybridoma cells
- These hybridoma cells have the function of producing antibodies and rapidly reproducing
- The hybridomas are screened for the production of the desired antibody. These are isolated.
- The desired hybridomas reproduce and produce antibodies which are then extracted. These are monoclonal antibodies.
myeloma cell - specific tumor cell
define monoclonal antibodies
Identical copies of one type of antibody which bind to one specific antigen.
2 uses of monoclonal antibodies
- pregnancy tests
- treating cancer
How are monoclonal antibodies used in pregnancy tests
Antibodies attached to dyes attach to HCG which is a hormone that is released during pregnancy. After binding with the hormone, the dye is released.
How are monoclonal antibodies used to treat cancer?
- binds to cancer and triggers white blood cells to kill them
- disrupts cell activity and stops reproduction
- carry radioactive or toxic substances which kill the cancerous cells
How was penicillin discovered?
- Alexander Flemming noticed that penicillium mould was killing bacteria in a petri dish.
- Ernst Chain and Howard Florey (from Oxford) took government funding and did research on it in 1940.
- During WW2 many doses of penicillin were produced.
