history

• disadvantages of germ theory


  - identifying bacteria couldn't explain every disease

  - viruses, genetics and lifestyle were all found to impact on health
• viruses


  - pasteur and koch were unable to find the cause of some diseases

  - these were microbes called viruses

  - viruses are too small to see under microscope
• Dmitry Ivanovsky


  - russian microbiologist

  - 1892: investigated mosaic, a disease that was killing tobacco plants

  - the cause was a tiny microbe that was in the water even after bacteria was removed
• Martinus Beijerinck


  - found that these microbes had different properties to bacteria

  - these microbes are viruses
• discovery of viruses


  - led to successful treatment

  - viruses aren't destroyed by antibiotics

  - instead antiviral drugs prevents the growth of a viral infection

  - but only the immune system can destroy a virus for good
• DNA


  - first described by francis crick and james watson

  - DNA structure double helix

  - discovery allowed other scientists to find the genes that cause genetic conditions

  - knowledge of genetic conditions has improved diagnosis and treatment

  - a synthetic protein can replace the faulty gene
• Human Genome Project


  an international study of the entire human genetic material

  
  

  2003
• lifestyle factors


  - healthy diet + exercise had always been suggested as ways to prevent illness

  - by the 20th century the lifestyle choices were linked to health conditions
• lifestyle factor changes


  - smoking was shown to cause lung cancer

  - obesity increases the chances of heart diseases and diabetes

  - drinking too much causes liver disease

  - too much UV light can cause skin cancer
• blood tests


  - tested blood groups

  - blood tests also have been used to test for a range of diseases
• Cholestrol Levels


  - can be found by using blood tests

  - diagnoses their chance of suffering a heart attack or stroke
• Blood tests- DNA + Cancer


  - checks dna

  - helps diagnose a genetic condition

  - shows whether a patient has a certain type of cancer
• X-rays


  - discovered Wilhelm Rontgen 1895

  - provide an image of the bones
• Ultrasound


  - advances in computers allowed use of ultrasound

  - high frequency sound waves

  - bounce off the patient's organs and other tissues to create an image of them on the computer
• CT and CAT scans


  - invented in 1972 by Godfrey Hounsfield

  - uses x-rays and a computer to make detailed images of parts of the patient's body
• MRI scans


  - first invented in 1970s but became widely used in the 1980s

  - uses extremely powerful radio waves and magnetic fields to construct images
• Monitoring the body


  since around 1900 devices have been introduced to allow doctors and patients to monitor the body
• Blood pressure


  - invented and developed in the 1880s and 1890s

  - let doctors and patients see whether disease, lifestyle factors or medicines cause high blood pressure which causes damage to the heart
• Blood sugar


  - introduced in the mid 20th century

  - allows those with diabetes to make sure their blood sugar is at the right level
• change


  1800s pasteur discovered that bacteria caused disease. but in 1900s doctors were able to treat bacterial diseases
• Alexander Fleming


  - Discovered penicillin in 1928

  - in 1928 he came to clean up some old culture dishes where he grew staphylococci for his experiments, a fungal spore had landed and grown on one of the dishes. The viruses stopped growing around the mould.
• Florey and Chain


  - pencillin needs to be purified

  - a breakthrough made by Howard Florey's team

  - Ernest Chain a teamed member, devised the freeze-drying technique which was an important part of the purification process
• Producing Penicillin


  - Florey and Chain didn't have enough resources to produce penicillin in large amounts

  - made penicillin for their first clinical trial by growing penicillium notatum in every container they could find, but soon ran out
• Florey and penicillin


  - Florey believed that penicillin would be vital for soldiers fighting in WW1

  - but british chemical firms were too busy making explosives to start mass productions

  - se he went to america
• America and Penicillin


  - weren't keen to help at the until they joined the war

  - in december 1941, the US gov began to give out grants to buisnesses that manufactured penicillin
• mass production


  - by 1942 British businesses also started mass producing penicillin

  - this gave sufficient amounts for military medics by 1944

  - after ww2 the cost of penicillin fell making it more accessible for general use

  - Fleming, Florey and Chain were awarded the Nobel prize in 1945
• Antibodies


  - natural defence mechanism of the body against germs, antibodies only attack specific microbes

  - they called these magic bullets

  - 1889, Paul Ehrlich set out to find chemicals that could act as synthetic antibodies
• Ehrlich


  - discovered dyes could kill the malaria and sleeping sickness
• 1905


  - the bacterium that causes the sexually transmitted disease syphilis was identified
• Ehrlich and team


  - decided to search for an arsenic compound that was a magic bullet for syphilis

  - hoped it would target the bacteria without poising the rest of the body

  - over 600 compounds were tried, none worked

  - Hata joined the team, rechecked the results and saw that compound number 606 worked, Salvarsan 606
• Gerhard Domagk


  - Red dye, Prontosil for streptococcus microbe from multiplying in mice

  - in 1935, Domagk daughter pricked herself with a needle and caught the disease. Domagk gave her a large dose of prontosil.
• Treatment for Cancer


  radiation: 1896-1898

  chemotherapy surgery (targeted therapy, late 1900s)
• Blood Transfusion


  - before 1700c blood transfusion was rarely successful

  - blood clotted if it was stored outside the body
• 1900 Karl Landsteiner


  - Identified human blood groups

  - certain blood groups can't be mixed as they will clot, clogging the blood vessels

  - safe blood transfusion = same blood groups
• WW1 1914


  - found that sodium citrate stopped blood clotting

  - blood can be stored outside the body

  - 1917, this was vital when the first ever blood bank was set up
• British National Blood Transfusion Service


  1946
• transplant of the cornea 1905


  performed during ww1 surgeons developed techniques for skin translation
• transplanted a kidney


  - first complete successful organ transplantation

  - livers, lungs, pancreas and bone marrow can now be transplanted
• first heart transplantation


  - carried out by a south african surgeon, Christiaan Barnard in 1967

  - patient survived for 18 days
• problems with transplants


  - rejection

  - immune system attacks the implant as if it were a virus

  - success of early transplant operations was limited because doctors lacked effective immunosuppressants

  - since 1970, researchers have developed more effect immunosuppressants, more safe