modern medicine

• despite their succeed with bacteria, pasteur and koch were unable to find the cause of some diseases, as they were caused by microbes called viruses, which were too small to see under a microscope
• in 1898 a dutch scientist found that these microbes causing disease had different properties to bacteria and labelled them viruses
• the discovery of viruses led to successful treatment
• unlike bacteria, viruses aren destroyed by antibiotics, instead doctors can prescribe antiviral drugs, but they only prevent an infection from growing - only the body’s immune system can destroy a virus for good
• genes are chemical ‘instructions’ that plan out human characteristics, which are stored in cells as DNA which is a mix of parents’ DNA
• the structure of DNA, being a double helix that can reproduce by splitting was first described in 1953 by Francis Crick and James Watson
• Watson and Crick’s discovery allowed other scientists to find the genes that cause genetic conditions, including cystic fibrosis, haemophilia and sickle-cell anaemia
• knowledge of genetic conditions has improved diagnosis and treatment of them, scientists can now produce a synthetic protein to replicate the work of a faulty gene and treat inherited conditions using techniques like gene therapy
• a healthy diet, exercise and other lifestyle factors have long been suggested as ways to prevent illness, but was only in the 20th century that lifestyle choices were linked to particular health conditions
• smoking has been shown to cause lung cancer
• obesity increases the chance of getting heart disease of diabetes
• drinking too much alcohol has been shown to cause liver disease
• overexposure to ultraviolet radiation can cause skin cancer
• blood tests were first introduced to test blood groups before blood transfusions. since then, blood tests have been used to test for a range of diseases
• blood tests can be used to check a patient’s cholesterol level. this can help diagnose their chance of suffering a heart attack or stroke
• blood tests can be used to check a patient’s DNA. this can help diagnose a genetic condition
• some blood tests can be used to show whether a patient has a certain type of cancer
• the use of medical scans began in 1895 when x-rays were discovered. they passed through soft flesh, but less well through bone. they also affect photographic film
• advances in computers allowed doctors to use ultrasound scanning which uses high frequency sound waves, which bounce off the patient’s organs and other tissues to create an image of them on a computer
• computer tomography (CT) scans were invented in 1972. they use x-rays and a computer to make detailer images of parts of the patient‘s body
• magnetic response imaging (MRI) scans were initially invented in the 1970s but became widely used in the 1980s. these use extremely powerful radio waves and magnetic fields to construct images
• since around 1900, devices have been introduced to allow doctors and patients to monitor the body
• blood pressure monitors were invented and developed in the 1880s and 1890s. they let doctors and patients see whether disease, lifestyle factors or medicines are causing high blood pressure, which can cause damage to the heart
• blood sugar monitors were introduced in the mid-20th century. they allow those with diabetes to make sure their blood sugar is at the right level
• alexander flemming saw many soldiers die of septic wounds caused by bacteria when he was working in an army hospital during WW1
• he identified the antiseptic substance in tears in 1922, but this only worked on some germs
• one day in 1928 flemming came to clean up some old petri dishes where he had been growing bacteria for his experiments. there was a fungal spore on one of the dishes
• the colonies of the bacteria around the mould had stopped growing, the fungus was named penicillin which produced a substance that killed bacteria
• flemming published his findings in articles between 1929 and 1931, however nobody was willing to fund further research so he was unable to take his work further
• since it is a natural product, penicillin needs to be purified. a breakthrough was made by Florey’s team in oxford between 1938 and 1940. chain, a member of the team, devised the freeze-drying technique which was an important part of the purification process
• at first florey and chain didn't have the resources to produce penicillin in large amounts, they made penicillin for their first clinical trial by growing it in every container they could find. their patient began to recover, only to die when the penicillin ran out
• florey knew that penicillin could be vital in treating the wounds of soldiers fighting in WW2. british chemical firms were too busy making explosives to start mass production - so he went to america
• american firms were not keen to help until they joined the war in 1941. in december the us government began to give out grants to businesses that manufactured penicillin
• by 1943, british businesses had also started mass-producing penicillin. mass production was sufficient for the needs of the military medics in 1944
• after the war, the cost of penicillin fell, making it more accessible for general use
• fleming, florey and chain were awarded the nobel prize in 1945
• antibodies were identified as a natural defence mechanism of the body against germs. it was known that antibodies only attacked specific microbes so they were nicknamed magic bullets.
• in 1889, paul ehrlich set out to find chemicals that could act as synthetic antibodies
• ehrlich discovered dyes that could kill the malaria and sleeping sickness germs
• in 1905, the bacterium that causes the std syphilis was identified