Chapter B6- Preventing and treating disease Flashcards
vaccine
dead or inactive pathogenic material used in vaccination to develop immunity to a disease in a healthy person
preclinical testing
is carried out on a potential new medicine in a laboratory using cells, tissue and live animals
clinical trails
test potential new drugs on healthy and patient volunteers
placebo
a medicine that does not contain the active drug being tested, used in clinical trials of a new medicine
natural active immunity stages (A-G)
A. antibody number increases B. pathogens destroyed C. antibody numbers fall, not to ZERO D. memory cells remain E. antibodies made quickly F. greater number made G. antibody levels remain high for longer
how vaccine is made + works
- pathogen destroyed or inactive
- vaccine prepared
- injected
- correct antibodies made
- memory cells remain to produce correct antibodies rapidly on subsequent infections and quickly destroy the pathogen
painkillers, +eg
- do not kill pathogens
- can relieve symptoms of disease
- e.g. paracetamol, Calpol, nurofen, ibuprofen, morphine, aspirin, codeine
antibiotics
- disinfectants and antiseptics can’t be used inside the body
- kill bacteria
- do not kill viruses
- do not harm human cells
- some kill a wide range of bacteria
- others are very specific
- important you chose the right one
- important to complete course
- frequently given to intensively-farmed animals
a good medicine is :
- effective
- safe
- stable
- successfully taken into and removed from your body
effective meaning
must prevent or cure disease, at least make you feel better
stable meaning
must be able to use medicine under normal conditions and store it for some time
safe meaning
drug must not be too toxic or have acceptable side effects
successfully taken into and removed from your body meaning
reach its target and be cleared from your system once the work is done
how long does it take to bring a new medicine into a doctors surgery?
12 years
how much might it cost to get a medicine to this stage?
£1700 million
development of drugs order
- disease is targeted and treatments are developed
- search for possible drugs including computer design of molecules and screening of many chemicals
- possible drugs made in lab
why do we carry out preclinical testing?
predict how drugs behave in humans
clinical trials order
- clinical testing on healthy human volunteers
- testing on small number of patients
- trials with more patients
what does the drug get after testing?
a license
randomised
not a specific type of person
double-blind
group of patients with target disease, some are given placebo and some are given new medicine. randomly allocated. neither doctor now patient know.
controlled
patients health monitored carefully
peer review
other scientists working in the same area can check results over, to prevent false claims
advantages of monoclonal antibodies:
- only bind to specific diseased/damaged cells
- healthy cells not affected
- specificity means they could be used to treat on wide range of conditions
disadvantages of monoclonal antibodies:
- expensive
- initially created more side effects than expected (reduced now)
- difficult procedure
formation of monoclonal antibodies in rats
mouse is injected with antigen / protein • immune system is stimulated • produces lymphocytes • lymphocyte is combined with a tumour cell • to form a hybridoma cell • hybridoma cell divides • forms a clone of hybridoma cells • cells produce a specific antibody • many cells produce a lot of the antibody • antibody is purified
why is it more difficult to develop medicines against viruses than to develop antibiotics
- viral pathogens can only reproduce inside the body cells
- difficult to find drugs that can kill pathogens without killing body cells
- bacteria exists outside body cells and different from human cells
- antibiotics can kill bacteria cells without killing body cells
advantages of looking for new antibiotic compounds in living organisms
- anecdotal evidence of medicinal evidence can save us from having to try multiple different types of plants
- when used for a long and widespread time, suggests that there are fewer side effects
disadvantages of looking for new antibiotic compounds in living organisms
- difficult to source living material
- low concentrations
- difficult to isolate exact chemical
monoclonal antibodies uses
- pregnancy tests
- diagnosis of disease
- measuring and monitoring
- research
- treating disease
use of monoclonal antibodies to treat disease
- trigger immune system to recognise, attack and destroy cancer cells
- block receptors on surface of cancer cells, to stop growing and dividing
- carry toxic drugs or radioactive substances for radiation therapy, or chemicals that stop cells growing and dividing to attack the cancer cells directly, without harming other cells
