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Beta Blockers Against High Blood Pressure

  • Prolonged, high blood pressure → hypertension, risk factor of CHD (coronary heart disease)!
  • Risk factors associated with hypertension are stress, obesity, smoking, high intake of NaCl and alcohol
  • Smooth muscle in artery wall thickens → narrows lumen of the artery → heart must beat faster → contracts with greater force than normal
    • Increased risk of thrombosis and atheroma (fatty deposits form in artery walls)
    • β-receptors found on plasma membrane of smooth muscle cells in arteries, arterioles and heart
    • β-agonists are chemical messengers that fit into and stimulate β-receptors / muscle cells in the walls of arteries relax (increases size of lumen)
    • β-blockers are antagonists of β-agonists / block β-receptors on surface of muscle cells in arteries and heart due to their similar shape / β-agonist cannot bind anymore / reduces hypertension
  • [EXAM] β-blocker binds to receptor / receptor on heart (muscle cells) / adrenaline cannot bind / blood pressure falls because heart rate reduced/force of contraction reduced

Antibiotics

  • Produced as natural secretions by bacterial or fungal cells
    • Bacteria and fungi are secondary metabolites (produce antibiotics during a late stage of their life cycle)
    • Antibiotics inhibit growth of natural competitors
    • Gives antibiotic-secreting population an advantage in colonising it
  • Antibiotics harm pathogenic bacteria by
    • Bacteriostatic antibiotics that are slowing down their growth rate
    • Bactericidal antibiotics that kill pathogenic bacteria (in correct concentration)
  • Narrow-spectrum antibiotics (e.g. penicillin) are only effective on a few pathogens
  • Wide-spectrum antibiotics (e.g. chloramphenicol) are effective on many pathogens
  • Prevent formation of bacterial cell walls
    • Bacteria occupy a solution with a more negative water potential than their own cytoplasm
    • Without the cell wall, bacteria are exposed to this hostile environment
    • As a result, bacteria will swell, burst and die
    • > Review the principles of water potential
  • Prevent formation of bacterial proteins
    • By inhibiting DNA transcription or mRNA translation
    • Bacteria are unable to synthesise proteins → affects the metabolism of bacteria
  • NOTE: Antibiotics do not affect viruses

Monoclonal antibodies

Hybridoma

  • B-lymphocytes are fused with tumour cells in laboratory cultures
  • They divide rapidly to form a clone of identical cells
  • Specific monoclonal antibodies are continuously produced and useful as
    • Some are tumour markers (antigens not present on non-cancerous cells)
    • Monoclonal antibodies will only attach to cancer cells
    • Anti-cancer drug attached to monoclonal antibodies will deliver the drug directly to the cancer cells

Uses of monoclonal antibodies

  • Monoclonal antibody is an antibody that is of just one type
  • Used to target the treatment of cancer cells or to screen (AIDS) in contaminated blood
  • Antibody direct enzyme prodrug therapy techniques (ADEPT)
    • Monoclonal antibodies are tagged with an enzyme that converts the prodrug (inactive drug) to an active form that kills cells (i.e. is cytotoxic)
    • The prodrug is injected in high conc
    • Attached to a monoclonal antibody, enzyme activates the drug and kills only cancer cells
  • In immunoassays, they can be labelled (radioactively) making them easy to detect
  • In the enzyme-linked immunosorbant assay (ELISA) technique, they are immobilised on an inert base and a test solution is passed over them
    • Target antigen combines with immobilised monoclonal antibodies
    • Second antibody attaches with an enzyme and binds to the monoclonal antibodies and to the target antigen as well
    • Substrate is added which is converted to a coloured product by the added enzyme
    • Conc. of colour tells us the amount of antigens present in the test solution
  • Used to detect drugs in urine of athletics or in home pregnancy tests (where an antigen in human chorionic gonadotrophin (hCG) is secreted by the placenta)
  • Transplanted organs have non-self-antigens triggering antibodies to attack the organ, leading to its rejecting
    • T-Lymphocytes are needed for B-lymphocytes to function
    • Monoclonal antibodies against T-lymphocytes can be used to prevent B-lymphocytes from functioning, thus blocking the rejection of transplanted organs
  • [EXAM] Helping to diagnose between two pathogens because
    • Antigens are on cell-surface membrane
    • Monoclonal antibody reacts with specific antigen only
    • Thus, detects presence of special bacteria because of a different antigen on another, different bacteria