B6 Preventing and treating disease Flashcards
Antigen
a protein on the surface of a substance (often a pathogen) that triggers an immune response
How does a vaccine work?
Small amounts of a dead or inactive pathogen are put into your body, often by injection. The antigens in the vaccine stimulate the white blood cells into making antibodies. The antibodies destroy the antigens without any risk of you getting the disease. You are immune to future infections by the pathogen because your body can respond rapidly and make the correct antibody as if you had already had the disease.
Herd immunity
the protection given to a population against an outbreak of a specific disease when a very high percentage of the population are immune (usually through vaccination)
Aspirin originates from…
a compound found in the bark of willow trees
Name two drugs extracted from foxglove
digitalis and digoxin (help strengthen the heartbeat)
Who discovered penicillin?
Alexander Fleming
Why are most new drugs synthesised by chemists?
compounds showing promise can be modified to produce more powerful molecules that can be synthesised easily and cheaply
A good medicine should be…
effective, safe, stable, successfully taken into and removed from your body
First stage of preclinical drug trials
drugs are tested using computer models and human cells and tissues (grown using human stem cells in the laboratory)
Second stage of preclinical drug trials
drugs are tested on live animals to test efficacy, toxicity, and dosage
First stage of clinical trials
very low doses are given to healthy people to check for side effects
Second stage of clinical trials
the drug is tried on a small number of patients to check if it treats the disease
Third stage of clinical trials
bigger clinical trials take place to find the optimum dose
What are double blind trials?
when neither the doctor nor the patient knows whether the patient received a placebo
B Lymphocytes
white blood cells that make antibodies but cannot divide
Hybridoma cell
a hybrid cell formed when a lymphocyte is fused with a type of tumour cell
How are monoclonal antibodies produced?
B lymphocytes are fused with tumour cells to create a hybridoma. The hybridoma divide to produce a large number of clone cells which are then harvested for antibodies
How do monoclonal antibodies work in pregnancy tests?
Tiny amounts of the hormone HCG (produced in the early stages of pregnancy) are passed out in the urine. Monoclonal antibodies in the test bind to the hormone if it is present, and this is used to produce the colour change
What are monoclonal antibodies used for?
diagnosis in pregnancy tests, in labs to measure levels of hormones and other chemicals in the blood to detect pathogens for research, and to identify or locate specific molecules in cells or tissue
3 ways in which monoclonal antibodies are used to treat cancer cells
direct use to trigger the immune system to recognise, attack and destroy cancer cells, to block receptors on the surface of cancer cells and stop them growing and dividing, and to carry toxic drugs, radioactive substances or chemicals
Advantage of monoclonal antibodies
they can deliver substances to cancer cells without harming other cells in the body
Disadvantages of monoclonal antibodies
they have created more side effects than expected and are not yet as widely used as hoped when they were first developed