B6: Preventing And Treating Disease Flashcards
What is vaccination?
Vaccination involves injecting small amounts of dead or weakened pathogens into the body. This stimulates B lymphocytes to produce antibodies.
How does engulfing microorganisms protect against disease?
Some white blood cells ingest pathogens, digesting and destroying them so they cannot make you ill
How does producing antibodies protect against disease?
Some white blood cells produce special chemicals called antibodies. These target particular bacteria or viruses and destroy them. You need a unique antibody for each type of pathogen. When your white blood cells have produced antibodies once against a particular pathogen, they can be made very quickly if that pathogen gets into the body again. This stops you getting the disease twice.
How does producing antitoxins protect against disease?
Some white blood cells produce antitoxins. These counteract the toxins released by pathogens.
What is herd immunity?
Herd immunity is a form of indirect protection that applies only to contagious diseases. It occurs when a sufficient percentage of a population has become immune to an infection that the communicable pathogen cannot maintain itself in the population, its low incidence thereby reducing the likelihood of infection for individuals who lack immunity
What is digitalis used for and where does it come from?
- Digitalis is one of several drugs that can be extracted from foxgloves
- Been used since 18th century to help strengthen the heartbeat, especially for older patients with heart problems
- Large amounts of this chemical can act as poisons
What is aspirin used for and where does it come from?
- Aspirin originates from a compound found in the bark of willow trees
- The anti-inflammatory and pain relieving properties were first recorded in 400BC
- In 1897, Felix Hoffman synthesised acetyl salicylic acid (aspirin)- with fewer side effects and more effective at relieving pain and inflammation
What is penicillin used for and where does it come from?
- In 1928, Alexander Fleming was growing bacteria for study purpposes
- He noticed that lots of his culture plants had mould growing on them and realised something had killed the bacteria covering the gel
- Called the substance that killed bacteria ‘penicillin’ after the penicillium
- After Fleming’s discovery, Ernst Chain amd Howard Florey began trying to extract penicillin and succeeded
- Gave some to a man dying of blood infection and he recovered quickly until the penicillin ran out.
- Working with the Us company Pfizer, they made penicillin on an industrial scale
What is toxicity?
If drugs are toxic
What is efficacy?
If drugs seem to do their job
What is dosage?
How frequently and in what quantity the drug should be taken
What occurs during pre-clinical testing?
Researchers target a disease and make lots of possible new drugs. These are tested to find out their toxicity and efficacy. The chemicals which pass earlier tests are them tested on animals- giving information about possible doses and side affects.
What occurs during clinical testing?
Clinical trials use healthy volunteers and patients. At first, very low doses are given to check for side effect through double-blind trials. 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 so, larger clinical trials take place to find out the optimum dosage.
What is considered during the licensing stage?
If the medicine passes all legal tests, the drugs safety for the patients
What is an antigen?
Any substance that causes the body to make an immune response against that substance. Antigens include toxins, chemicals, bacteria, viruses, or other substances that come from outside the body.
What is an antibody?
Antibodies. are proteins produced by a type of white blood called lymphocytes close lymphocytes white blood cells which attack pathogens by producing antibodies
How are monoclonal antibodies made?
- A tumour cell (divides rapidly) is combined with a lymphocyte (makes specific antibodies)
- A hybridoma cell is made (makes specific antibodies and divides)
- Hybridoma cell is cloned
- Cloned cells make a specific antibody
- Monoclonal antibodies collected and purified
What is a tumour cell?
Makes specific antibodies but cannot divide
What is a lymphocyte?
Cell divides but doesn’t make antibodies
What is a hybridoma cell?
Cell divides and makes antibodies
What are monoclonal antobodies used to diagnose some diseases?
Monoclonal antibodies are made to bind to specific antigens found on pathogens, or on blood clots or on cancer cells. The monoclonal antibodies may also carry markers that make it easy for doctors to see where they have built up. This allows doctors to detect problems before they are seriously affecting a patient’s health.
What are the advantages of monoclonal antibodies?
- They only bimd to the specific disease or damaged cell that needs treatment
- Healthy cells are not affected at all
- The specificity of monoclonal antibodies means they can treat a wide range of conditions
- Potentially could become cheaper than conventional drugs
- Doctors now prepared for side affects and have treatments
- Development of skills and technology means they can be used in different ways
What are the disadvantages of monoclonal antobodies?
- Conventional drug treatment is carried all around the body in the blood and may have a devastating effect on healthy cells (eg: radiotherapy targets cancer cells but also effects healthy tissue
- Expensive to develop
- Initially had more side affects than expected- mouse cells triggered an immune system reaction within humans- thus not widely used or successful
- Producing the right monoclonal antibodies and attaching them to drugs and other compounds proved more difficult than expected.
How are monoclonal antibodies used in pregnancy tets?
- Monoclonal antibodies bind to the hormone human chorionic gonadotropin (HCG) that is made in early stages of pregnancy.
- Tiny amounts of the hormone are passed out of the body in the urine, monoclonal antibodies bind to the hormone if it is present, producing colour change, signalling positive result
How are monoclonal antibodies used for measuring and monitoring?
Monoclonal antibodies used in hospitals and laboratories to measure/ monitor levels of hormones and other chemicals in blood
How are monoclonal antibodies used in research?
Scientists produce the monoclonal antibodies linked to a molecule of a fluorescent dye. When the monoclonal antibodies bind to the desired molecules, scientists can see what has happened by observing build up of fluorescence
How are monoclonal antobodies used for the diagnosis of disease?
Monoclonal antibodies are made to bind to specific antigens found on pathogens or on blood clots or cancer cells. The monoclonal antibodies ,au also carry markers making it easy for doctors to see the build up location.
How are monoclonal antibodies used forntrating disease?
- Direct use of monoclonal antobodes to trigger the immune system to recognise, attack and destroy cancer cells
- Using monoclonal antibodies to block receptors on the surface of cancer cells and so stop the cells growing and dividing
- Cam be used to carry toxic substances or radioactive substances for radiation therapy or chemicals that stop cells growing and dividing to directly attack cancer cells without harming other cells in the body
What are two precautions that a person with RSV could take to reduce spread of virus?
- Isolation may prevent the inhalation and transfer of droplets through the environment and air and through the spread of pathogens through direct and indirect contact
- The spread may also be reduced through increased hygiene to prevent the spread of the virus through indirect contact on surfaces and direct contact with others
Why are patients given placebos?
To take into account a psychological effect
What is the purpose of double blind trials to?
To avoid bias
How do antibiotics work?
Antibiotics are able to kill bacteria and/ or prevent bacterial replication in several ways:
* Weaken the bacterial cell wall
* Disrupt protein synthesis in the ribosomes
* Inhibit DNA replication
* Disrupt metabolic reaction
How do bacteria become drug resistant?
- When there are high number of bacteria, some of them have mutated and become antibiotic resistant strain
- When antibiotic is added, the sensitive strains are killed. However, no effect against antibiotic resistant strain
- Now, the antibiotic resistant strain can grow and multiply
- Moreover, they can transfer drug-resistance to other bacteria and forming a group of antibiotic resistant bacteria
How has antibiotic resistance risen?
- Bacteria sometimes develop random mutations in their DNA, changing their characteristics
- Results on bacteria being less effected or more resistant to the antibiotic
- Other bacteria that isn’t resistant is damaged/ destroyed by the antibiotics, leaving no competition for the mutated, resistant bacteria to replicate, quickly forming a new colony of its own, all with the gene for antibiotic resistance- antibiotic-resistant strain
Why is antibiotic resistance a significant public health concern?
- After using antibiotics, you remain infected so you can pass antibiotic resistant strains of bacteria to others
- If they go tot he doctor and get the same antibiotics it will not work so they must receive a different antibiotic
- Occasionally, some of the bacteria will develop resistance to this type of antibiotics, allowing it to replicate with no competition and form another antibiotic-resistant strain of bacteria
- This process may repeat, continuing to become resistant to more types of bacteria
