Chaper B6- Preventing And Treating Disease Flashcards
What are antigens?
The unique proteins on the surface of every cell
What other names is vaccination known as?
Immunisation
What is a vaccine?
Dead or inactive pathogenic material used in vaccination to develop immunity to a disease in a healthy person
What does a vaccination do?
Stimulates your white blood cells to produce the antibodies needed to fight the pathogen and prevent you from getting ill
What is the benefit of a vaccination?
Saves lives as if your body comes into contact with the disease it can produce the right antibodies very rapidly that can fight it off and keep you healthy
What disease has been wiped out by vaccines?
Smallpox
Describe the process of a vaccination
Small amounts of dead pathogens are injectors into your body often by injections
The antigens in the vaccine stimulate your white blood cells into making antibodies, which destroy the antigens without any risk of you getting the diseases
You are then immune from the disease if you are subject to future infection as your body can rapidly respond and make the correct antibody
What is herd immunity?
If a large proportion of the population is immune to a disease, then the spread of the pathogen is reduced. This is called herd immunity
What happens if the number of people having vaccines falls?
Herd immunity disappears
Give an example of herd immunity disappearing
The whooping cough in the 1970’s- many parents heard the vaccine was unsafe and numbers fell from 80% vaccinated to 30%. In ten following years many children died to whooping cough.
Give examples of painkillers
Aspirin
Paracetamol
Do painkillers cure your any faster?
No- you have to wait for your immune system to overcome the pathogens before you get better
When did antibiotics first become available?
1940’s
How do antibiotics work?
Killing the bacteria that cause disease whilst they are inside your body- they damage the bacterial cells without harming your cells.
How do you take antibiotics?
Pill form
Syrup form
Straight into the bloodstream (if urgent)
Does an antibiotic work on all bacteria?
no- specific bacteria should be tested using specific antibiotics that are effective against them
Can antibiotics kill viruses?
No as viruses reproduce inside a cell, and so to kill the virus is to harm your own cells and tissues at the same time
What is antibiotic resistance?
Strains of bacteria are becoming resistant to the antibiotics- this means they no longe have an effect so cannot cure the disease.
Give examples of plant medicines
Digoxin- comes from foxgloves plant. Has been used since 18th century to strengthen the heartbeat. However large amounts can be poisonous
Aspirin- originated from a compound found in willow trees- is anti inflammatory and pain relieving. In 1897 Felix Hoffman synthesised acetyl salicylic acid, which had fewer side effects than the willow bark. It did till commonly used today
What year was penicillin discovered?
1928
Who discovered penicillin?
Alexander Fleming
What did Fleming notice?
After one holiday, when he had left his culture plates without a lid, he noticed a ring in the jelly around some of the spots of mould, and realised something had killed the bacteria. He tried to extract this penicillin but failed
What did Ernst Chain and Howard Florey do?
Set out trying to extract penicillin. They were successful, and gave it to a patient dying of a blood infection. He recovered for a bit until the penicillin ran out and he died. Despite his death, they had proven that penicillin could kill bacterial disease in people
What potential medicines are scientists looking into?
The noni fruit
Soil samples
A good medicine is…
Effective- works
Safe- doesn’t cause harm
Stable- can be used in normal conditions and can be stored
Successfully taken into and removed from yours system- must be able to be cleared once it’s target has been reached
What does toxicity mean?
Possible drugs are toxic
What does efficacy mean?
Possible drugs seem to do their job
In the laboratory, what are potential drugs tested on?
Cells tissues and even whole organs
What happens if a drug passes the laboratory tests?
Tested on animals- gives us knowledge on dosage and side effects and what effects happen on a whole organism
What is preclinical testing?
Dugs being tested in the laboratory on cells tissues and animals
What are clinical trials?
Trialling drugs on healthy volunteers and patients
What are the stages of clinical trials?
First, a very low dosage is prescribed to healthy people to check for side effects
If it is safe, a small number is tried on patients to see if it treats the disease
If it is safe, bigger clinical trials take place to find the optimum dosage
It all these tests are passed, doctors can prescribe it as it becomes licensed
What are double blind trials?
A group of patients with a target disease take part- some are given a placebo that does not contain the drug, whilst others are given the new medicine. Neither the doctors not patients know who has received the real drug. The patients health is ministered carefully. This tells if the drug is actually physically effective, and not just a result of the placebo effect
Name a body that looks into drug testing and trials
National institute for clinical excellence (NICE), decide which drugs give good value for money and should be prescribed by the NHS
Define dosage
The size of a dose of medicine or drug
What is a hybridomas?
Cells creates during the production of monoclonal antibodies by the fusion of an antibody-specific lymphocyte and a tumour cell
What are monoclonal antibodies?
Proteins that are formed to target particular cells or chemicals in the body
What is a lymphocyte?
A type of white blood cell
Can lymphocytes divide?
No
Can tumour cells divide?
Tumour cells can divide rapidly
Can tumour cells make antibodies?
No
How do scientists create monoclonal antibodies?
Scientists take lymphocytes ( which make antibodies) and tumour cells, and combine them to from a hybridoma cell. This then multiples and creates monoclonal antibodies that are separated, purified and can be used
How are monoclonal antibodies used?
As they react with a specific antigen ( as the formation of the monoclonal antibody was from that single cell), they can target and bind to a specific antigen.
Give real life examples of used of monoclonal antibodies
Pregnancy tests Diagnosis of disease Measuring and monitoring Research Treating disease
How does a pregnancy test use monoclonal antibodies?
These rely on monoclonal antibodies that bind to the hormone made in the early stage of pregnancy (HCG) which is passed out in the urine- the monoclonal antibody binds to this hormone and produces the colour on pregnancy tests
How are monoclonal antibodies used to diagnose disease?
Bond to specific antigens found on pathogens, or on blood clots or cancer cells. They can carry markers so doctors can see where the have built up.
How are monoclonal antibodies used to treat disease?
To trigger the immune system to recognise, attack and destroy cancer cells
To block receptors on the surface of cancer cells and so stop the cells from growing and dividing
To carry toxic drugs to attack the cancer cells directly, without harming other cells in your body
Advantages of monoclonal antibodies
- Only bind to a specific or diseased/ damaged cell that needs treatment- healthy cells aren’t affected
- Can treat a wide range of conditions
Disadvantage of monoclonal antibodies
- Expensive
- Not widely used
- Initially there were side effects as mouse cells were used
- More difficult than expected to produce correctly
What are monoclonal antibodies?
A single clone of identical hybridoma cells
What are monoclonal antibodies specific to?
A single binding site on one protein antigen
Why are monoclonal antibody useful in medicine?
As we can produce monoclonal antibodies against any antigen we want
