B6 Preventing and treating disease Flashcards
What does every cell have on its surface?
unique proteins called antigens
The antigens on the microorganisms that get into your body are…
…different to the ones on your own cells
Your _____ system recognises that the ____ on the micro-organisms that get into your body are _____ to the ones on your __ cells
i) immune
ii) antigens
iii) different
iv) own
What happens after your immune system recognises the difference between the antigens on the micro-organisms that enter your body?
your WBCs make specific anti-bodies
What do antibodies do?
join up with antigens and inactivate or destroy that particular pathogen
What can some of your white blood cells do?
memory cells ‘remember’ the right antibody needed to destroy a particular pathogen
What happens if you meet the same pathogen you have before?
the memory cells can make the same antibody very quickly to kill the pathogen, so you become immune to the disease
Why do you get ill the first time you meet a new pathogen
there is a delay while your body sorts out the right antibody needed
Some pathogens can make you seriously ill very quick;y. Give an example
meningitis
Why can you die very quickly by serious diseases?
the disease affects the body before it manages to make the right antibodies
What does immunization involve?
giving a vaccine made of a dead or inactivated form of a disease-causing microorganism
What do dead or inactivated form of a disease-causing microoganism stimulates?
your body’s natural immune response to invading pathogens
What happens in a vaccination?
- small amount of dead/inactive forms of a pathogen is introduced into the body
- stimulates while blood cells to product antibodies needed to fight the pathogen and prevent you from being ill
Why do vaccinations work?
if you meet the same, live pathogen, your white blood cells can respond rapidly
- make right antibodies
- just as if you already had the disease
What do doctors use vaccines to protect us from?
against both bacterial diseases and viral diseases
Name two bacterial diseases
tetanus and diphtheria
Name three viral diseases
polio, measles and mumps
What is herd immunity?
if a large proportion of the population is immune to a disease, spread of pathogen reduces and may even disappear
What is a drawback of herd immunity?
it will take money and determination
Often medicine doesn’t affect the pathogen that is causing the problems. What does it do?
eases the symptoms and makes you feel better
Give examples of drugs that are very useful pain killers?
aspirin and paracetamol
Painkillers help relieve but…
have no effect on the viruses that have entered your tissues and made you feel ill
What are antiseptics and disinfectants used for?
to kill bacteria outside the body; far too poisonous to use inside your body
What are the drugs that have really changed the treatment of communicable diseases?
antibiotics
What are antibiotics?
Medicines that can work inside your body to kill BACTERIAL pathogens
When were antibiotics first widely available?
1940s
An example of antibiotic?
penicillin
how do antibiotics work?
killing the bacterua that cause disease whilst they are in your body
What do antibiotics do?
damage the bacterial cells without harming your own cells
What form do antibiotics take
a pill/syrup
-very ill, antibiotics may be put straight into your bloodstream
Why are antibiotics sometimes put straight into the bloodstream?
make sure they reach the pathogens as soon as possible
Some antibiotics…
Others are…
…kill a wide range of bacteria
…are very specific and only work against particular bacteria
Specific bacteria should be treated with…
the specific antibiotic that is effective against them
What do viruses do?
reproduce inside the cells of your body
Why is is extremely difficult to develop drugs that will kill viruses?
risk of famaging the cells and tissues of your body as the same time
Drawback of antibiotics?
cannot kill viral pathogens
-strains of bacteria that are resistant to antibiotics are evolving
Traditionally, where were drugs extracted from?
plants or microorganisms such as moulds
How do scientists make more effective drugs nowadays?
often adapt chemicals from microorganisms, plants and animals
What is digitalis and digoxin?
one of several drugs extracted from foxgloves that have been used since the 18th century to help strengthen the heartbeat
What do doctors still use digoxin for?
older patients with heart problems
Large amounts of these chemicals in drugs can act as?
poisons
aspirin originates from?
a compound found in the bark of willow trees
What sort of properties to aspirin have and when were they recorded?
anti-flammatory and pain-relieving properties
-400BC
In 1897, what did Felix Hoffman do?
synthesised acetyl salicylic acid
What is aspirin and what does it do?
acetyl salicylic acid
-relieves pain and inflammation better than willow bark but has fewer side effects
aspirin is still commonly used to treat what?
a wide range of health problems
In the early 20th century, scientists were looking for what?
chemicals that might kill bacteria and cure infectious diseases
In 1928, who was growing bacteria for study purposes?
Alexander Fleming
Why was Alexander Fleming rather careless?
often left the lids off his culture plates- health and safety procedures were not as good in those days
After one holiday, what did Fleming see?
lots of his culture plates had mould growing on them
What did Fleming notice in his culture plates after one holiday?
a clear ring in the jelly around some of the spots of mould
What did Flemings realise?
something had killed the bacteria covering the gel
What did Flemings call the substance that killed bacteria and why?
penicillin after penicillium mould that produced
After his discovery, what did Flemings do?
unsuccessfully tried for several years to extract as active juice from the mould before giving up and moving on to other work
What happened about 10 years after Fleming’s discovery?
Ernst Chain and Howard Florey were set about trying tying to extract penicillin
What did Ernst Chain and Howard Florey do to extract penicillin?
- they gave some penicillin to a man dying of a blood infection
- recovered almost miraculously
What did Ernst Chain and Howard Florey demonstrate?
that pencillin could cure bacterial infections in people
What happened after Ernst Chain and Florey extracted penicillin?
Working with the company pfizer in the USA, they made penicillin on an industrial scale; producing enough to supply the demands of WW2
Give an example where finding new medicine is difficult?
it is not easy to find chemicals that kill bacteria without damaging human cells
How are most drugs now synthesised?
by research chemists working in the pharmaceutical industry using chemical banks and computer models
(however, the starting point may still be a chemical extracted from a plant or microorganism)
What happens to compounds showing promise as antibiotics?
can be modified to produce more powerful molecules that can be synthesized easily and cheaply
Why are scientists also collecting soil samples globally and searching for microorganisms?
to produce a new antibuitic against antibiotic-resistant bacteria
How much of soil microorganisms can be cultured in the lab?
1% of soil microorganisms
What have scientists developed that would enable them to grow microorganisms in the soil in a controlled way
A special unit
Using the special unit technology, scientists were able to do what in 2015?
they announced a completely new type of antibiotic from some soil bacteria
In tests so far, what have the soil bacteria proven to do?
the antibiotic has destroyed all bacteria including MRSA, and other antibiotic resistant pathogens
-it worked in mice
Scientists test new medicines where?
in the labratory
What has to happen to every new medical treatment?
to be extensively treated and trialed in a series of stages before it is used
Why must new medical treatments be tested and trialled?
to make sure it works well and is as safe as possible
A good medicine is what four things?
- Effective
- Safe
- Stable
- Successfully taken into and removed from your body
What happens when scientists research a new medicine?
they have to make sure all the conditions are met
Making sure that a medicine is up to all the right conditions can take how long?
up to 12 years to bring a new medicine into your doctor’s surgery
How much does it cost for medicines to be extensively tested and trialled?
costs around £1700 million, including failures and capital costs
Researchers target a disease and then…
make lots of possible new deugs
Possible new drugs are tested in the laboratory why?
to find out if they are toxic and if they seem to do their job
-toxicity and efficacy
In the lab, what are the possible new drugs tested on?
cells, tissues, and even whole organs
At what stage do the new possible drugs usually fail at?
many chemicals fail at the testing of cells, tissues and even whole organs
What happens to the small number of chemiclas that do pass the tests on cells, tissues and even whole organs and why?
labratory tested on animals to find out how they work in a whole living organism
Why may testing on a whole living organism be useful?
gives information about possible doses and side effects
What are the tissues and animals used for when testing and developing drugs?
as models to predict how the drugs may behave in humans
What is the testing called when it is on cells, tissues and live animals?
preclinical testing
Drugs that pass animal testing move on to what?
clinical trials
What do clinical trials involve?
using healthy volunteers and patients
What happens in in clinical trials?
-very low doses are given to healthy people to check for side effects
In clinical trials, what happens if the drug is found to be safe?
it is tried on a small number of patients to see if it treats the disease
If the drug seems to be safe and effective to affected people, what happens?
bigger clinical trials take place to find the optimum dose for the drug
What happens if the medicine passes all the legal tests?
it is licenced so your doctor can prescribe it
-its safety will be monitored for as long as it is used
In human trials, what do scientists use?
a double blind trial
Why is a double blind trial used?
to see just how effective the new medice is
What do the double blind trials involve?
a group of patients with the target disease agree ti take part in the trials
- some are given a placebo
- some are given new medicine
- patients randomly allocated to the different groups
- neither the doctor nor the patients know who has received the real drug/placebo until the trial is complete
- the patients health is monitored carefully
A placebo…
does not contain the drug
What does the placebo often contain instead?
a different drug that is already used to treat the disease
Placebos contain a different drug that is already used to treat a disease. What does this mean?
the patient is not deprived of treatment while taking part in the trial
What happens to the results of drug tests and trials like all scientific research?
Published in journals after they have been scritinised in a process of peer review
Why are the results of drug tests and trials published in journals?
so that other scientists working in the same area can check the results over, helping to prevent false claims
Who looks at the published results of drug trials and decide which drugs give good value for money and should be prescribed by the NHS
National bodies such as the National Institute for Health and Care Excellence
(NICE)
Like vaccinations, monoclonal antibodies rely on what?
on the immune system
What are monoclonal antibodies?
proteins that are produced to target particular cells or chemicals in the body
What are lymphocytes and what do they do?
They are a type of white blood cell that can make antibodies but cannot divide
Tumour cells do not usually make antibodies. What can they do?
divide rapidly to make a clone of cells
True or false. All mammals, including mice, produce lymphocytes.
True
What is a hybridoma?
the cell made when scientists combine mice lymphocytes (that have been stimulated to make a particular antibody) with a type of tumour cell
What do single hybridoma cells do?
divide to make a large number of identical cells that all produce the same antibodies
What happens are single hybridoma cells divide to make a large number of identical cells that all produce the same antibodies?
the antibodies are collected and purified
After they had been collected and purified, the antibodies are called
monoclonal antibodies
What are scientists doing now to produce monoclonal antibodies that are less likely to be rejected by human cells?
combining mice cells with human cells
Step by step production of monoclonal antibodies
- i) B lymphocutes make specific antibodies but do not divide
ii) tumour cells that do not make antibodies but divide - A hypridoma cell (makes specific antibodies and divides)
- The cells are cloned
- Monoclonal antibodies are sepearted, purified and can be used
What are antigens and where are they often found?
protein molecules that are often found on the surface of cells (free protein molecules can act as antigens)
The monoclonal antibodies produced from a ____ ___ of cells are specific to one ____ ___ on one ____ antigen
i) single clone
ii) binding site
iii) specific
Uses of monoclonal antibodies?
- pregnancy tests
- diagnosis of disease
- measuring and monitoring
- research
- treating disease
Explain how pregnancy tests work?
-relies on monoclonal antibodies that bind to the hormone human chorionic gonadotrophin (HCG) that is made in the early stages of pregnancy.
How do monoclonal antibodies help diagnosis of disease
monoclonal antibodies are made to bind to specific antigens foound on pathogens, or on blood clots or on cancer cells
How are monoclonal antibodies able to make it easy for doctors to detect problems before they are seriously affecting a patient’s health
monoclonal antibodies can also carry markers that make it easy for doctors to see where they have built up
How can monoclonal antibodies be used for measuring and monitoring?
monoclonal antibodies are used in hospotals and laboratories to measure or monitor the levels sd
