B6 Flashcards
Preventing and treating disease
How do vaccines work ?
- vaccine contains dead or inactive pathogens
- when injected, the white blood cells are able to figure out which antibodies work to destroy the pathogen without risk of being too slow to save the person
- memory cells in the immune system store this information
- when the body encounters the actual pathogen, memory cells can quickly produce the right antibodies to destroy the pathogens before they make the person feel (too) unwell
Which pathogens can vaccines immunise humans against ?
- viruses
- bacteria
What is herd immunity ?
When enough members of a population are immune to a disease (through prior infection or vaccination) that the spread of the disease is greatly reduced
- facilitated GREATLY by vaccination; if less people are vaccinated, more people are infected and fatalities rise
What do painkillers do ?
- relieve SYMPTOMS of illness like headache, sore throat etc.
- DO NOT kill pathogens, so do not affect the rate at which one recovers
What are antibiotics ?
Chemicals that are safe to be used internally and which kill BACTERIA
- have no effect on other types of pathogen like viruses or protists
- some antibiotics are specific, whilst others kill a wide range of bacteria (used when unsure which is causing an infection)
- antibiotic-resistant bacterial strains become more common with frequent use, making the diseases caused by them more difficult to treat
Which two medicines that strengthen the heartbeats of patients can be extracted from foxgloves ?
- digitalis
- digoxin
Where does aspirin come from, and what does it do ?
- willow tree bark
- anti-inflammation and pain-relief
Where does penicillin come from ?
penicillium mould
Who discovered penicillin ?
Alexander Fleming
Where do scientists obtain new chemicals for development of new antibiotics ?
Most chemicals synthesised in the lab, however the starting point is often chemicals found naturally in plants or specially cultured soil bacteria
Describe the stages in development of new drugs
- pre-clinical trials
[] chemicals that could be developed into useful antibiotics are tested on cells, then tissues, then live animals
[] tests for efficacy and toxicity levels - phase 1 clinical trials
[] around 10 healthy patients
[] safety and side effects in humans are investigated - phase 2 clinical trials
[] around 100 patients affected with the targeted disease
[] tests for dosage and efficacy in humans - phase 3 clinical trials
[] 1000s of patients
[] tests for efficacy and side effects using a wider sample of people - results of the trials are peer reviewed before being published to make sure that they are reliable, reproducible and not biased
- drug goes through legal tests and licensing and then is marketed
What is a double-blind trial ?
A medical trial of a drug in which neither the doctor nor patient knows whether they are in the placebo group or the group where the new drug is being tested
- to keep it ethical, volunteers in the placebo group are often given drugs currently used to treat the disease so they aren’t denied treatment
What are hybridomas and why are they useful ?
Cells made by combining antibody-producing cells with fast-dividing tumour cells
- can be used to produce monoclonal antibodies on a large scale for medical purposes due to how fast the hybridoma cells clone themselves
How are monoclonal antibodies made ?
- hybridoma cell made by combining B lymphocyte that is able to produce specific antibodies and a fast-dividing tumour cell
- hybridoma clones itself very fast
- hybridoma cells produce large quantities of the desired antibodies
- monoclonal antibodies are collected and purified before use
How do pregnancy tests work ?
- urine of a pregnant person contains HGC hormone
- person urinates on test strip
[] on test strip, monoclonal antibodies specific to HCG (attached to a particle of coloured dye)
[] if HCG is present in the urine, they bind to it - urine washes the monoclonal antibodies down the test strip
- at the end of the test strip, there is a line of more HCG-specific monoclonal antibodies fixed to the test strip
[] the dye-attached antibodies if bound to HCG from earlier on get trapped on this line when the HCG gets bound to again by the fixed antibodies
[] accumulation of these antibodies means a clear blue line forms on the test strip - after the fixed line of HCG-specific antibodies, there is another line of monoclonal antibodies specific to the chemicals in the blue dye
[] these catch the rest of the monoclonal antibodies that have not bound to HCG
[] accumulation of these antibodies means another blue line forms on the test strip - its the control line - two blue lines = positive pregnancy test
- one blue line (on top) = negative pregnancy test
- no blue lines or a blue line only on the bottom = invalid test
Name 5 uses of monoclonal antibodies
- diagnosis of disease
- treatment of disease
- pregnancy tests
- research of a particular molecule/chemical
- monitoring/measuring levels of a pathogen, molecule or chemical in the body
Describe 3 ways in which monoclonal antibodies are used to treat cancer currently
- monoclonal antibodies bind to antigens on the cancer cell and send out a signal to white blood cells to attack the cancer cell
- monoclonal antibodies attached to radioactive particles or a certain drug/chemical bind to cancer cells and the radiation/chemical kills the cancer cell without harming human body cells and tissues surrounding it
- monoclonal antibodies bind to antigens on cancer cells and block the cell’s receptors for growth-stimulants so that it does not grow or divide
Describe the key advantages and disadvantages of monoclonal antibodies
advantages:
- are specific to certain chemicals/cells/proteins, so would not affect the surroundings
- have a wide range of potential applications across humans, plants and animals
disadvantages:
- are not as widely used as first hoped due to
[] many side effects (mostly because of the use of solely mouse lymphocytes initially - with the incorporation of human lymphocytes this is improving)
[] cost of production
[] difficulty of production and attaching compounds to them
