B6 - Preventing/treating disease Flashcards
What is vaccination? Explain how it works:
-introducing small quantities of dead/inactive pathogens into the bloodstream
-stimulates the WBCs to produce complementary antibodies against the antigens found on the pathogen
-if the same pathogen enters the body, the WBCs can respond quickly to produce lots of the antibodies needed, preventing infection
Describe how antibody concentrations in the blood change with the 1st and 2nd vaccinations:
-1st vaccine, increases conc. slowly for a short amount of time
-2nd vaccine/infection, body responds sooner, increasing conc. much higher and faster for a sustained amount of time
How can the spread of pathogens be reducing by immunising a large proportion of the population?
-herd immunity
-spread of infectious pathogen is limited, as more people are vaccinated so it has less places to spread, and is contained
Vaccination is the process of getting a vaccine, immunisation is the process of developing immunity against a pathogen
How do antibiotics and painkillers differ? Give an example of each:
-antibiotics (eg penicillin) kill specific infectious bacteria within the body
-painkillers (eg aspirin) only treat the symptoms of an infection, and cannot kill bacteria
How does the modern day production of drugs differ from how they were made traditionally?
-traditionally extracted from plants/microorganisms
-new drugs are mostly synthesised in a lab by pharmaceutical industries, but they can still originate from plants/microorganisms
Give some examples of traditional drugs extracted from natural sources:
-heart drug digitalis from foxgloves
-painkiller aspirin from willow
-penicillin discovered by Alexander Fleming from Penicillium mould
How are new drugs tested before offering them to volunteers?
done in preclinical trials on cells, tissues, and live animals (eg mice)
How are clinical trials of drugs performed?
-very low doses are given to healthy volunteers to test toxicity
-increased until a maximum dose is found before side-effects occur
-if it is safe, further trials are done on sick patients to find optimum dose for maximum efficacy
-can use double blind trials
-results are peer reviewed extensively, then published
How does a double blind trial work?
-neither patients nor those administering the drug know which one is a placebo or not
-only the researchers know to ensure there is no unconscious bias
-the placebo acts as a control, as it shows that the drug has an effect on the patient, and isn’t purely psychological
What are MCAs, and why are they useful?
-monoclonal antibodies
-antibodies produced from a single clone of cells that can be used to target specific pathogens due to the antigens found on them
Describe and explain the production of monoclonal antibodies:
-antigens are injected into mouse
-extract and combine the lymphocytes with a tumour cell (myeloma) to create hybridoma cells
-find hybridoma which makes the MCAs specific to the antigen needed
-clone hybridoma to create many rapidly-dividing cells that produce the antibodies
SAY LYMPHOCYTES BECAUSE THEY DON’T ACCEPT WBCs
They divide rapidly because they are tumour cells
Give some general uses of MCAs:
-diagnosis (eg in pregnancy tests)
-to locate/identify specific molecules (eg hormones) by binding to them with fluorescent dyes
-treating cancer (carries a toxic chemical to tumour cells without harming others)
Why aren’t MCAs as widely used as previously hoped?
they produce too many side effects
How could MCAs be used to treat a cancer?
-attach a toxic chemical to MCA
-it will only bind to the specific tumour cells
-toxic chemical stops the tumour cells dividing
How could a vaccine work to prevent the person from developing a HIV infection?
-inactive HIV virus is injected into bloodstream
-WBCs produce complementary antibodies against HIV’s antigens
-if HIV enters the body, complementary antibodies are produced quickly, and destroy the HIV viruses
