Preventing and Treating Diseases



- if a pathogen enters the body, the immune system tries to destroy the pathogen

- vaccination involves introducing small amounts of dead or inactive forms of a pathogen into your body to stimulate the white blood cells to produce antibodies

    if the same live pathogen re-enters the body, the white blood cells respond quickly to produce the correct antibodies, preventing infections

- if a large proportion of the population is immune to a pathogen, the spread of the pathogen is much reduced

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Antibiotics and Painkillers

- painkillers and other medicines treat the symptons of diseases but do not kill the pathogens that cause it

- antibiotics cure bacterial diseases by killing ther bacterial pathogens inside your body

- the use of antibiotics has greatly reduced deaths from infectious diseases

- the emergence of strains of bacteria resistant to antibiotics is the matter of great concern

- antibiotics do not destroy viruses because viruses reproduce inside the cells, it is difficult to develop drugs that can destroy viruses without damaging your body cells

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Discovering Drugs

- traditionally drugs were extracted from plants (e.g. dig italis) or from micro organisms (e.g. penicillin)

- penicillin was discovered by Alexander Fleming from the penicillin mould

- most new drugs are synthesised by chemists in the pharaceutical industry, however the starting point may still be a chemical extracted from a plant

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Developing Drugs

- new medical drugs are extensively tested for efficacy, toxicity and dosage

- new drugs are tested in the laboratory on cells

    tissues and live animals

    clinical trials use healthy volunteers and patients

    low doses are used to test for safety

    followed by higher doses to test for optimum dose

- in double blind trials, some patients are given a placebo

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Uses of Monoclonal Antibodies

- monoclonal antibodies are used in the treatment of diseases 

- they have been developed against the antigens on cancer cells

- if a monoclonal antibody is bound to a radioactive substance, a toxic drug or a chemical that stops cells growing and dividing, it will deliver the substance to the cancer cells without harming other cells in the body

- monoclonal antibodies have created more side effects than expected and are not yet as widely used as hoped when they were first developed

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Making Monoclonal Antibodies

- monoclonal antibodies are produced from a single clone of cells, each type is specific to one binding site on a specific protein antigen so they an target specific chemicals

- monoclonal antibodies are produced by stimulating mouse lymphocytes to make a specific antibody, large amounts of the specific monoclonal antibody can be collected and purified

- monoclonal antibodies are used:

    for diagnosis in pregnancy tests

    in labs to measure levels of hormones and other chemicals in the blood to detect pathogens for research

    to identify or locate specific molecules in cells or tissue

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