Chapter 6

• What is a vaccine? How does it work?

  -Vaccinations involve injecting small amounts of dead or inactive pathogens.

  -These carry antigens, which cause your white blood cells to produce antibodies to attack them.

  -If live pathogens of the same type appear at a later date, the white blood cells can rapidly mass-produce antibodies to kill off the pathogen.

  -The vaccinated person is now immune to the pathogen and won't get ill.
• What are the Pros and Cons of Vaccinations?

  Pros

  -Vaccines have helped control lots of infectious diseases that were once common in the UK

  -Epidemics can be avoided if a large percentage of the population is vaccinated

  -Protection from diseases

  
  

  Cons

  -Vaccines don't always work-sometimes they don't give you immunity

  -people can sometimes have bad reactions to a vaccine
• What is herd immunity?


  When a majority of a population are vaccinated against a disease. This means that even people who have not been vaccinated are less likely to get it because there are fewer people to catch it from.
• What are painkillers? What do they do?

  Painkillers are drugs that relieve pain. They don't tackle the cause of the disease, they just help to reduce the symptoms. Essentially, reducing the symptoms without tackling the underlying cause.
• What are antibiotics? What do they do?

  -Antibiotics kill the bacteria causing the problem without killing your own body cells.

  -Different antibiotics kill different types of bacteria

  -Antibiotics don't destroy viruses. Viruses reproduce using your own body cells, making it difficult to develop drugs that destroy just the virus.
• What is antibiotic resistance?

  -Bacteria can mutate, sometimes the mutations cause them to be resistant to an antibiotic

  -If you have an infection, some of the bacteria might be resistant to antibiotics. This means that when you treat the infection, only the non-resistant strains of bacteria will be killed. The individual resistant bacteria will survive and reproduce, and the population of the resistant strain will increase.

  -This could cause a serious infection that couldn't be cured by antibiotics
• How do you slow down the rate of development of antibiotic resistant strains?


  -Doctors shouldn't over-prescribe antibiotics. Only prescribe antibiotics for serious bacterial infections.

  -You should finish the whole course of antibiotics and don't stop taking them when you feel better.
• What are the origins of drugs?

  -Plants produce a variety of chemicals to defend themselves against pests and pathogens.

  -Some of these chemicals can be used as dugs for treatment or relief
• Why is it important to test drugs?

  New drugs have to go through a thorough testing procedure to make sure they are safe and effective. There are three main stages in drug testing: preclinical testing on human cells and tissues, preclinical testing on live animals, and clinical testing on human volunteers.
• What does the preclinical testing involve?

  Cells and tissues

  -drugs are tested on human cells and tissues in the lab. Human cells and tissues can't be used to test drugs that affect whole or multiple body systems

  
  

  Live animals

  -testing the drug on live animals tests its efficacy, toxicity and to find out the best dosage that should be given and how often it should be given
• What does Clinical trials involve?


  -If the drug passes the tests on animals, it is then tested on human volunteers in a clinical trial

  -First, the drug is tested on healthy volunteers to make sure there are no harmful side effects when the body is working normally. A very low dose of the drug is given and is gradually increased

  -If the results of the tests on healthy volunteers are good, the drugs can be tested on people suffering from the illness. The optimum dose is found
• What is a placebo and how are they used in drug testing?

  To see how well a drug works, patients are randomly put into two groups. One is given the new drug, the other is given a placebo (a substance like the drug being tested but doesn't do anything). This is so the doctor can see the actual difference the drug makes-it allows for the placebo effect
• What is the placebo effect?


  when the patient expects the treatment to work and so feels better, even though the treatment isn't doing anything.
• What are blind and double-blind trials?

  Clinical trials are blind- the patient in the study doesn't know whether they're getting the drug or the placebo

  
  

  They can also be double blind- neither the patient nor the doctor knows until all the results have been gathered. This is to prevent the doctors monitoring the patients and analysing the results aren't subconsciously influenced by their knowledge.
• How do you produce monoclonal antibodies?

  -Monoclonal antibodies are produced from lots of clones of a single white blood cell (a lymphocyte).

  -This means all the antibodies are identical and will only target one specific protein antigen.

  - However lymphocytes don't divide easily, whereas tumour cells can be grown very easily.

  -It's possible to fuse a mouse lymphocyte with a tumour cell to create a cell called a hybridoma, which can be cloned very easily and produce the same antibodies.

  -These can be collected and purified.
• What two things are fused together to make a hybridoma cell?

  a mouse B-lymphocyte and a fast-dividing tumour cells
• How are monoclonal antibodies used in pregnancy tests?

  A hormone called HCG is found in the urine of women only when they are pregnant. Pregnancy testing sticks use monoclonal antibodies to detect this hormone

  
  

  -The bit of the stick where you urinate on has some antibodies to the hormone, with blue beads attached. The test strip has some more antibodies to the hormone stuck onto it.
• How does the pregnancy test show as positive?

  If you're pregnant and wee on the stick, the hormone binds to the antibodies on the blue beads. The urine moves up the stick, carrying the hormone and the beads. The beads and hormone bind to the antibodies on the strip. So the blue beads get stuck on the strip, turning it blue
• How does the pregnancy test show as negative?

  If you're not pregnant, and you wee on the stick, the urine still moves up the stick carrying the blue beads. but there's nothing to stick the blue beads onto the test strip, so it doesn't go blue
• What does the control window on a pregnancy test do?


  The control window shows the person using the test whether the test has worked correctly. The control window contains antibodies to the antibodies that are attached to the blue beads. This means that once the blue beads reach the window, the antibodies attached to them will bind to the antibodies stuck to the control window.

  The window should show blue whether the test is negative or positive to show it has worked.
• How can monoclonal antibodies be used to treat cancer?

  -Different cells in the body have different antigens on their cell surface. So you can make monoclonal antibodies that will bind to specific cells in the body.

  -Cancer cells have antigens on their cell membranes that aren't on normal cells called tumour markers. In a lab, you can make monoclonal antibodies that will bind to the tumour markers.

  -An anti-cancer drug can be attached to the antibodies. (a radioactive substance, toxic drug or chemical which stops cancer cells growing / dividing)

  -The antibodies are given to the patient in a drip, and the drug kills the cancer cell, but not any other cells

  
• How could you use monoclonal antibodies in research?

  -Monoclonal antibodies can be used to locate specific molecules on a cell or in a tissue

  -Monoclonal antibodies are made that will bind to the specific molecules that are being looked for.

  -The antibodies are bound to a fluorescent dye.

  -If the molecules are present, the antibodies will attach to them, and they can be detected with the dye.
• What are problems with monoclonal antibodies?


  Although, they are a good cancer treatment as they only target cancerous cells, and don't harm normal body cells. They have lots of unexpected side effects. they can cause fever, vomiting and low blood pressure. This means they aren't as widely used in treatments as doctors thought they would be.
• What is a vaccine? How does it work?

  -Vaccinations involve injecting small amounts of dead or inactive pathogens.

  -These carry antigens, which cause your white blood cells to produce antibodies to attack them.

  -If live pathogens of the same type appear at a later date, the white blood cells can rapidly mass-produce antibodies to kill off the pathogen.

  -The vaccinated person is now immune to the pathogen and won't get ill.
• What are the Pros and Cons of Vaccinations?

  Pros

  -Vaccines have helped control lots of infectious diseases that were once common in the UK

  -Epidemics can be avoided if a large percentage of the population is vaccinated

  -Protection from diseases

  
  

  Cons

  -Vaccines don't always work-sometimes they don't give you immunity

  -people can sometimes have bad reactions to a vaccine
• What is herd immunity?


  When a majority of a population are vaccinated against a disease. This means that even people who have not been vaccinated are less likely to get it because there are fewer people to catch it from.
• What are painkillers? What do they do?


  Painkillers are drugs that relieve pain. They don't tackle the cause of the disease, they just help to reduce the symptoms. Essentially, reducing the symptoms without tackling the underlying cause.
• What are antibiotics? What do they do?

  -Antibiotics kill the bacteria causing the problem without killing your own body cells.

  -Different antibiotics kill different types of bacteria

  -Antibiotics don't destroy viruses. Viruses reproduce using your own body cells, making it difficult to develop drugs that destroy just the virus.
• What is antibiotic resistance?


  -Bacteria can mutate, sometimes the mutations cause them to be resistant to an antibiotic

  -If you have an infection, some of the bacteria might be resistant to antibiotics. This means that when you treat the infection, only the non-resistant strains of bacteria will be killed. The individual resistant bacteria will survive and reproduce, and the population of the resistant strain will increase.

  -This could cause a serious infection that couldn't be cured by antibiotics
• How do you slow down the rate of development of antibiotic resistant strains?

  -Doctors shouldn't over-prescribe antibiotics. Only prescribe antibiotics for serious bacterial infections.

  -You should finish the whole course of antibiotics and don't stop taking them when you feel better.
• What are the origins of drugs?

  -Plants produce a variety of chemicals to defend themselves against pests and pathogens.

  -Some of these chemicals can be used as dugs for treatment or relief
• Why is it important to test drugs?


  New drugs have to go through a thorough testing procedure to make sure they are safe and effective. There are three main stages in drug testing: preclinical testing on human cells and tissues, preclinical testing on live animals, and clinical testing on human volunteers.
• What does the preclinical testing involve?

  Cells and tissues

  -drugs are tested on human cells and tissues in the lab. Human cells and tissues can't be used to test drugs that affect whole or multiple body systems

  
  

  Live animals

  -testing the drug on live animals tests its efficacy, toxicity and to find out the best dosage that should be given and how often it should be given
• What does Clinical trials involve?


  -If the drug passes the tests on animals, it is then tested on human volunteers in a clinical trial

  -First, the drug is tested on healthy volunteers to make sure there are no harmful side effects when the body is working normally. A very low dose of the drug is given and is gradually increased

  -If the results of the tests on healthy volunteers are good, the drugs can be tested on people suffering from the illness. The optimum dose is found
• What is a placebo and how are they used in drug testing?


  To see how well a drug works, patients are randomly put into two groups. One is given the new drug, the other is given a placebo (a substance like the drug being tested but doesn't do anything). This is so the doctor can see the actual difference the drug makes-it allows for the placebo effect
• What is the placebo effect?


  when the patient expects the treatment to work and so feels better, even though the treatment isn't doing anything.
• What are blind and double-blind trials?


  Clinical trials are blind- the patient in the study doesn't know whether they're getting the drug or the placebo

  
  

  They can also be double blind- neither the patient nor the doctor knows until all the results have been gathered. This is to prevent the doctors monitoring the patients and analysing the results aren't subconsciously influenced by their knowledge.
• How do you produce monoclonal antibodies?

  -Monoclonal antibodies are produced from lots of clones of a single white blood cell (a lymphocyte).

  -This means all the antibodies are identical and will only target one specific protein antigen.

  - However lymphocytes don't divide easily, whereas tumour cells can be grown very easily.

  -It's possible to fuse a mouse lymphocyte with a tumour cell to create a cell called a hybridoma, which can be cloned very easily and produce the same antibodies.

  -These can be collected and purified.
• What two things are fused together to make a hybridoma cell?


  a mouse B-lymphocyte and a fast-dividing tumour cells
• How are monoclonal antibodies used in pregnancy tests?

  A hormone called HCG is found in the urine of women only when they are pregnant. Pregnancy testing sticks use monoclonal antibodies to detect this hormone

  
  

  -The bit of the stick where you urinate on has some antibodies to the hormone, with blue beads attached. The test strip has some more antibodies to the hormone stuck onto it.