Disease 2 Flashcards
(26 cards)
What happens in vaccination?
- A dead or inactive version of a pathogen is injected into the blood
- Lymphocytes recognise that the antigens are foreign and produce antibodies against them
- Memory cells are created which remain in the blood
Why do some parents not want their children to become vaccinated?
A false rumour was spread in the 1990s that the MMR vaccine caused an increased risk of autism. It was disproved and there is no evidence linking vaccines to autism.
Following this rumour, numbers of deaths from measles and mumps increased sharply
What types of pathogen can people be injected against?
Bacteria
Viruses
What are the benefits of vaccination?
- Prevents a person developing a serious illness or dying
- Can eradicate a disease e.g. smallpox
- Protects a population from the spread of a disease
What are the weaknesses of vaccinations?
- Some people may suffer side effects and have allergic reactions
- Viruses mutate regularly so the vaccine may have to be adapted
What are antibiotics?
Medicines used to destroy bacteria
How do antibiotics work?
They destroy the cell walls of bacteria so they can’t divide and eventually burst and die
Why do antibiotics not kill viruses?
Viruses stay inside host cells and are not themselves living cells
How does antibiotic resistance happen?
Bacteria can evolve and mutate to become resilient to antibiotics
How can we stop antibiotic resistance?
- Doctors should only prescribe antibiotics if they are needed and not for minor illnesses
- Doctors should vary the type of antibiotic prescribed as much as possible
- Patients should continue using the antibiotic until all bacteria are killed
Why is MRSA a problem?
It is a bacteria resistant to many antibiotics which is evolving via natural selection faster than we can make new antibiotics to destroy it
What control measures are used in hospitals against MRSA?
- Patients entering the hospital are screened for MRSA
- Hand washing and hand sanitising
- Stringent hygiene measures when dealing with open wounds
What difference is there between how drugs were made in the past and how they are made now?
In the past, most drugs were extracted from plants and microorganisms e.g. aspirin comes from willow trees + penicillin comes from Penicillium mould
Nowadays, most drugs are synthesised by chemists in the pharmaceutical industry, but ingredients for these may chemicals from plants
What are the types of drugs produced?
Painkillers
Antibiotics
Antiviral drugs
Why do drugs need to be tested first?
To ensure they are safe and work properly and check if there are any serious side effects
What criteria are drugs tested on?
Efficacy - Does the drug work?
Toxicity - Is the drug safe?
Dose - How much of the drug is needed?
What are the two stages of drug testing?
- Preclinical testing
- Testing on human cells grown in a laboratory
- Testing on animals
- Testing on healthy human volunteers
Low doses of the drug are initially used - Clinical testing
- Testing on small groups of patients affected by the condition the drug is targeting
What is a placebo?
A fake drug that has no effect on the body given to a control group in human drug trials (the other group receives the actual drug being tested)
This is to show that results are due to the effects of the drug and not the psychological expectations of the individual
What are the two most common types of drug trials?
Blind trials:
Volunteers do not know which group they are in and neither do the researchers
Double blind trials:
Neither the volunteers nor the researchers know which group is which which removes chance of bias and makes the results more reliable
What are monoclonal antibodies?
Identical copies of one type of antibody
How are monoclonal antibodies produced?
- An antigen is injected into a mouse
- The mouse produces lymphocytes which produce antibodies specific to the antigen
- Lymphocytes are removed during a small operation and fused with myeloma cells (tumour cells) to form hybridoma cells which divide indefinitely
- Hybridoma cells divide and produce millions of monoclonal antibodies specific to the original antigen
- Antibodies are extracted by centrifugation, filtration, and chromatography
Why are lymphocytes fused with tumour cells?
Tumour cells divide extremely fast, but don’t contain antibodies.
Lymphocytes contain antibodies, but don’t divide as fast.
Merging them together produces a hybridoma cell with both of these qualities
How can monoclonal antibodies be used to test for disease?
They can be attached to dyes that glow fluorescent under UV light to see which parts of the body contain particular molecules.
It not only tests if an infection is present, but also the extent of the infection due to how fluorescent the area is.
How can monoclonal antibodies be used for tissue typing?
If an organ is a good tissue match for the recipient, their antigens on their cells must be similar so the immune system is less likely tor recognise the object as foreign.
Monoclonal antibodies can bind to the recipient’s white blood cells that produce antibodies against the new organ and inactivate them which reduces chance of infection
