B6 preventing and treating disease Flashcards
(22 cards)
What are painkillers?
Painkillers
are chemicals that relieve the symptoms but do not kill the pathogens. Common examples include paracetamol and aspirin, and they can relieve a headache or a sore throat.
As the symptoms are treated, your immune system still needs to combat the pathogen.
What are antibiotics?
Antibiotics are substances that slow down or stop the growth of bacteria. They are commonly prescribed medicines, examples include penicillin and amoxicillin. These can be taken to cure the disease by killing the pathogen, but only cure bacterial diseases and not viral ones.
What is herd immunity?
Herd immunity occurs when a large portion of a population becomes immune to a disease, which protects those who are not immune. This immunity can be achieved through vaccination or prior infection. When a high percentage of people are immune, it reduces the likelihood of an outbreak because there are fewer individuals who can be infected and transmit the disease.
What is vaccination?
Pathogens
are microbes that cause
diseases. Vaccines allow a dead or altered form of the disease causing pathogen to be introduced into the body, which contain a specific antigen. This causes the immune system, specifically the white blood cells, to produce complementary
antibodies, which target and attach to the antigen. When a white blood cell engulfs and digests a pathogen it is called phagocytosis. Memory cells remember the disease and can act quickly when there is a secondary outbreak.
What happens after vaccination?
During the
primary infection
the antibodies slowly increase, peak at around ten days and then gradually decrease. A second exposure to the same pathogen causes the white blood cells to respond quickly in order to produce lots of the relevant antibodies, which prevents infection.
How are drugs extracted from plants?
Certain drugs can be extracted from natural sources. For example, willow bark to help cure fevers and pains. It was later discovered that the active ingredient was salicylic acid. This was modified by chemists into the substance we call aspirin, which is less irritating to the stomach than salicylic acid. Another example is the heart drug, digitalis which is extracted from foxgloves.
Plants are still important today, but most plant drugs are now created in a laboratory by scientists at
pharmaceutical
companies. These companies now have
synthetic
versions of the plant extracts, and use these as the starting point to develop new drugs.
New medical drugs have to be tested to ensure that they work, and are safe, before they can be prescribed.
What is thalidomide and its legacy?
Thalidomide is a medical drug that caused unexpected and serious damage to unborn babies in the 1950s and 1960s. Thalidomide was developed as a sleeping pill, but it was also thought to be useful for easing morning sickness in pregnant women. Unfortunately, it had not been tested for use in this way.
By 1960 thalidomide was found to damage the development of unborn babies, especially if it had been taken in the first four to eight weeks of pregnancy. The drug led to the arms or legs of the babies being very short or incompletely formed. More than 10,000 babies were affected around the world. As a result of this disaster, thalidomide was banned. Drug testing was also made more rigorous than before.
What are new drugs checked for?
New drug need to be tested and trialled before doctors prescribe them and patients take them. This allows drugs to be checked for:
safety
effectiveness
dosage
What are monoclonal antibodies?
‘Mono’ means ‘one’ and ‘clone’ means ‘identical copy’.
Monoclonal antibodies are identical copies of one type of antibody.
Antibodies are proteins produced by a type of white blood called lymphocytes. Pathogens have proteins on their surface called
antigens. When a pathogen infects the body, the lymphocytes recognise these antigens as foreign and attack them by producing antibodies.
Antibodies bind to specific antigens on pathogens. This means that only one type of antibody will bind to a matching antigen. Scientists discovered that we could make antibodies to bind to antigens on other substances, and not just those on pathogens. Once bound, the antigens - and the substances they are found on - are merged tightly together. This makes them easier to identify and deal with.
How are monoclonal antibodies formed?
An antigen is injected into a mouse
The mouse naturally produces lymphocytes, which produce antibodies specific to the antigen
Spleen cells which produce the lymphocytes are removed during a small operation
The spleen cells are fused with human cancerous white blood cells called
myeloma cells
to form
hybridoma cells
which divide indefinitely
These hybridoma cells divide and produce millions of monoclonal antibodies specific to the original antigen
How do monoclonal antibodies help pregnancy diagnosis?
Pregnancy test kits use
monoclonal antibodies. These have been designed to bind with a hormone called HCG which is found only in the urine of pregnant women. Monoclonal antibodies are attached to the end of a pregnancy test stick onto which a woman urinates. If she is pregnant, HCG will be present in her urine and will bind to the monoclonal antibodies on the test stick. This will cause a change in colour or pattern which will indicate pregnancy. These specific monoclonal antibodies in the pregnancy test will only bind with HCG.
How can monoclonal antibodies be used for treating cancer?
They can directly target cancer cells, marking them for destruction by the immune system.
They can block receptors on cancer cells, preventing them from receiving growth signals.
They can deliver toxic substances or radiation directly to cancer cells.
They can block proteins that suppress the immune system, allowing the immune system to attack the cancer.
Benefits of monoclonal antibodies
Benefits
Monoclonal antibodies can be designed to bind to, and identify, almost any substance. They can be used for many purposes:
-testing for pregnancy by detecting HCG hormones in urine
-testing for diseases such herpes and chlamydia, and HIV which can lead to the development of AIDS
-to treat conditions like cancer by carrying drugs directly to the tumour cells, and helping the immune system attack them monoclonal antibodies can be produced quickly despite the fact that it can be time consuming when they are made for the first time
Why can’t cold be vaccinated against?
It is easily mutated so that the vaccine wont work after its mutated.
Limitations of antibiotics:
Antibiotics only work against bacteria. They are ineffective against viral infections like the common cold or flu.
Antibiotic resistance: Overuse and misuse of antibiotics can lead to bacteria developing resistance, making the drugs less effective or completely ineffective.
Side effects: Antibiotics can cause side effects such as nausea, diarrhoea, and allergic reactions.
Disruption of gut microbiome: Antibiotics can kill beneficial bacteria in the gut, leading to digestive issues and other health problems.
Not a substitute for hygiene: Antibiotics do not replace the need for good hygiene practices like handwashing to prevent infections.
define efficacy, toxicity and dosage
Efficacy: How well a treatment works in ideal conditions
e.g.,a clinical trial. It’s about whether the treatment can produce a desired effect.
Toxicity: The degree to which a substance is harmful to the body. It refers to the adverse effects caused by a treatment.
Dosage: The specific amount of a medication or treatment given at one time, and how often it’s administered.
What are placebos used in Double blind trials?
Blinding: Placebos ensure that participants and researchers don’t know who is receiving the actual treatment versus the inactive substance. This prevents bias in reporting or interpreting results.
The Placebo Effect: Some people experience a perceived benefit from a treatment simply because they believe they are receiving it. Placebos help researchers measure and account for this “placebo effect,” separating it from the actual drug’s effect.
Comparison: By comparing the outcomes of the placebo group with the treatment group, researchers can determine if the treatment’s effects are statistically significant and not just due to chance or psychological factors.
Explain the stages of clinical testing
Preclinical Research: This involves lab and animal testing to assess safety and potential efficacy.
Phase 1: A small group of healthy volunteers receive the drug to evaluate its safety, dosage, and how it’s absorbed and eliminated by the body.
Phase 2: A larger group of patients with the target disease or condition receive the drug to assess its effectiveness and identify side effects.
Phase 3: A large, randomised controlled trial is conducted with a diverse group of patients to confirm effectiveness, monitor side effects, compare it to commonly used treatments, and gather information that will allow the drug to be used safely.
Regulatory Review: The Medicines and Healthcare products Regulatory Agency reviews the data from all phases to decide whether to approve the drug for use.
Why are results peer reviewed?
Peer review is used to evaluate the quality and validity of research findings before they are published. It helps to ensure that published research is rigorous, accurate, and contributes meaningfully to its field. It helps against false claims.
Enzyme-Linked Immunosorhent Assays
ELISAs are biochemical assays used to detect the presence of a substance, usually an antigen, in a biological sample. They rely on antibodies and enzyme-mediated colour changes to quantify the target substance.
Limitations of mAbs
High cost: The development and production of mAbs can be expensive, limiting their accessibility.
Immunogenicity: Although mAbs are designed to be highly specific, they can still trigger an immune response in some patients, leading to the production of anti-drug antibodies
and can cause adverse reactions
Ethical reasons: Some people argue it isn’t ethical to use animals such as mice in research
Evaluate mAbs against cancer
Advantages:
Specificity: Monoclonal antibodies are highly specific, targeting only cancer cells and reducing damage to healthy cells. This can lead to fewer side effects compared to traditional treatments like chemotherapy.
Versatility: They can be used in various ways, as mentioned above, making them adaptable to different types of cancer and treatment strategies.
Diagnostic Applications: Monoclonal antibodies can also be used in diagnostic tests to detect cancer cells early on.
Disadvantages:
Side Effects: Although generally fewer than chemotherapy, side effects can still occur, such as allergic reactions, flu-like symptoms, and skin rashes.
Resistance: Cancer cells can develop resistance to monoclonal antibodies over time, reducing their effectiveness.
Cost: Monoclonal antibody treatments can be very expensive, limiting their accessibility.
Not a Cure: Monoclonal antibodies are often used to manage cancer and improve quality of life, but they may not always provide a complete cure.
In conclusion, monoclonal antibodies offer a promising approach to treating diseases like cancer due to their specificity and versatility. However, it’s important to consider the potential side effects, the possibility of resistance, and the cost associated with these treatments.
