Non-infectious disease and disease prevention

• Development of coronary heart diseases:

  1. cholesterol and other substances in blood deposit on the inner wall of the coronary arteries -> a plaque is formed
  2. The plaque hardens and narrows the arteries
  3. this reduces the amount of blood carrying oxygen and nutrients flowing to the cardiac muscles
  4. some cardiac muscle cells die due to lack of oxygen and nutrients
  5. heart attack occurs
• Type 1 diabetes( insulin-dependent )

  major cause: no insulin is produced as the insulin-secreting cells in the pancreas is destroyed

  risk factors:family history
• Type 2 diabetes

  major cause: body cells are insensitive to insulin

  risk factors:

  • ageing
  • obesity
  • lack of exercise
  • family history
• Management of diabetes mellitus:

  • monitoring of blood glucose level
  • healthy eating( keep the blood glucose level within the normal range)
  • regular exercise(increase the sensitivity of body cells to insulin and reduce body weight)->help patients with type 2
  • regular injection of insulin into the body->help patients with type 1 diabetes
• The carbon monoxide in cigarette smoke will reduce the oxygen-carrying capacity of the blood
• • The workload of the heart-muscle cells is increased during exercise
  • narrowing of coronary artery results in a reduced blood flow to the heart muscles, and thus reducing the supply of oxygen and glucose to the heart muscle cells
  • some heart muscle cells die
• • Old people have a decline in immune response by the body
  • mutation may have accumulated to a high level as one ages
• How mutation leads to diabetes mellitus:

  • a random mutation leads to a change in the base sequence of gene involved in insulin production
  • mRNA transcribed has a different codon
  • polypeptide translated has a different amino acid sequence
  • it folds into a new protein with a different shape
  • change of the original protein will result in an absence of enzyme for insulin production
  • it causes the inability in insulin synthesis in patients of type 1 diabetes mellitus
• Why diabetes patients have a higher risk in marathon race?

  • Diabetes patients fail to produce sufficient insulin to stimulate liver cells to convert glucose in blood to glycogen
  • less glycogen is available in diabetes patients than healthy participants
  • less energy can be released by breaking down glycogen to support running over a long distance
  • insufficent glucose is supplied to cardiac muscle for respiration leading to elevated risk of heart attack than healthy participants
• • Spike proteins presented in antigen presenting cells activate B cells
  • B cells multiply and differentiate into memory B cells and plasma cells
  • Plasma cells release specific antibodies against the spike proteins of COVID-19 viruses
  • Memory B cells remember the type of antigens and will respond quickly and produce a higher level of specific antibodies when a booster injection is applied
• mRNA vaccine is non-infectious while conventional vaccines might be contaminated with live and active diseases
• mRNA vaccine is temperature sensitive. It must be kept at low temperatures during transport or storage while conventional vaccines are relatively stable under room temperature
• Disadvantages of convalescent plasma theory:

  • Limited number of eligible donors
  • Convalescent plasma from a recovered patient can only treat one to three COVID-19 patients
  • The specific antibody level of the recipients will not stay long
• • Diabetic patients lack insulin
  • Hence, the liver fails to convert excess glucose into glycogen for storage
  • During intense exercise, blood glucose is consumed for muscle activities
  • The blood glucose level drops continuously without replenishment from the glycogen stored
• Older people have been exposed to carcinogens for a longer time. The mutations in genes have accumulated and therefore the risk of cancer development increases.