Pathogenesis and the Disease State

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Pathogenesis and the Disease State
2014-10-26 19:39:20
test Two
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  1. Classical Signs of Disease and Inflammation
    • rubor (red flushing)
    • tumore (swelling)
    • calor (heat)
    • dolor (pain)
    • Functio Laesa (loss of function)
  2. Tumor
    fluid and immune comp rush in--> swelling
  3. calor (heat)
    • classic mechanisms for two reason:
    • --> for viral infections: you don't feel like doing anything; limiting ability to host cells--> slow doown reproduction of pathogens
    • --> pathogens stay 2-2.5 degrees in normal body temperature; above, bacteria can't get in
  4. Most bacteria have __ signs of disease and inflammation
  5. Classical Signs of disease and inflammation: who defined them?
    1 to 4 as defined by Aulus Cornelius Celsus in De Medicina

    5 as defined by Galen of Pergamon
  6. Signs are __. Symptoms are __. Syndrome is __.

    subjective changes (have to deal with individually)

  7. Components of the diseased state
    signs: objective changes in the normal physiology of an organism (eg: fever, rash, that are readily observable)

    symptoms: subjective changes in the physiology of an organism, eg: loss of weight, loss of appetite, fatigue

    sydrome: the characteristic manifestation of a specific set of signs and symptoms
  8. What are the stages of progression of an infection?
    incubation stage

    prodomal stage

    clinical stage

    decline stae

    convalescent stage
  9. incubation stage
    the period during which the organism colonizes a healthy host. Towards the end of the period, the illness slowly becomes apparent

    get exposed and start to feel a little bit off
  10. Prodromal stage
    the first symptoms of the disease appear. The organism has effectively colonized the organism and is rapidly reproducing. This is a stage at where the disease is highly communicable

    you know; you're effectively colonized and organism is reproducing
  11. Clinical stage
    the characteristic symptoms peak

    characteristic symptoms peak
  12. Decline stage
    the first signs of the regression of the disease as well as the loss of communicability

    feeling slightly better
  13. Convalescent stage
    the organism returns to full health

    shortest of the lot
  14. Infection/ Disease periods
    latent, comunicability, and illness period
  15. Latent period
    that part of the incubation stage that spans between the initial infection and the first apparent sign of the illness

    when infected
  16. Communicability period
    the time span between the first signs of the illness and the first signs of the regression of the disease

    90% of the time that you're sick
  17. Illness period (acute phase)
    the period of time between the end of the latent period and the beginning of the convalescent stage

    Latent period to the convalescent stage
  18. Avoidance of the Immune System
    some species of bacteria can bind hte non functional end of an antibody

    Neisseria sp. bind the proteins of the complement cascade, thus preventing their own lysis

    Salmonella sp. are able to live within phagocytic white blood cells

    the pili of Neisseria sp. inhibit the binding of phagocytic white cells
  19. Avoidance of the Immune System:

    __ of antigens binds __. 

    Bind at the __ end of the antibody

    Can live in __ and avoid __.


    fragment antigen binding (Fab fragment)


  20. Neisseria have __ and __.
    • weird pilis
    • inhibit WBC by binding
  21. Virulence Factors 

    --> pathogen
    an organism that is capable of causing disease
  22. Virulence factors

    --> pathogenicity
    the qualitative description of an organism's ability to invade a host and cause disease
  23. Virulence factors

    the quantitative description of an organism's ability to invade a host and case disease
  24. Virulence factors

    the ability of a microorganism to invade a host cell or tissue and be able to multiply on or within them, i.e. the ability to establish an infection
  25. Explain the disease process
    attachment can lead to three things

    --> non-invasive disease: localized symptoms; if a toxin is present, systemic symptoms

    --> local invasive disease: localized symptoms 

    --> invasive disease: systemic symptoms

    All can lead to possible sequela
  26. Sequela
    a pathological condition resulting from a disease, injury,therapy, or other trauma.
  27. What do pathogens have that help them adhere?
    adhesin: surface molecules on a pathogen, called adhesins or ligands, bind specifically to complementary surface receptors on cells of certain host tissues
  28. What is the second step after attachment?

    - noninvasive, local invasive, or invasive
  29. Penetration is mediated by __. Which ones?
    bacterial enzsymes

    • - hyaluronidase (digests hyaluronic acid)
    • - coagulase (promotes fibrin clotting)
    • - streptokinase (dissolves fibrin clots)
  30. Hyaluronidase
    bacterial enzyme that digests hyaluronic acid

    • - Glucosaminoglycan
    • ---> Tissue structure
    • ---> wound healing

    - promotes spread of bacteria into tissues

    - penetrates through the connective tissue layer
  31. Hyaluronidase
    • secreted by
    • - streptococcus sp. 
    • - staphycoccus sp. 
    • - clostridium sp
  32. Coagulase
    bacterial enzyme that promotes fibrin clotting

    • promotes localizing bacteria 
    • - lack of spread/ penetration

    - damage to wall of BV--> forms clot to make damage less noticeable and shields it from immune system

    - sets up infection under clot
  33. Coagulase is secreted by __. 

    Common pathologies: __

    uncommon pathologies? __
    • staphylococcus sp. 
    • Yersinia sp. 

    pimples, boils, abscess

    Uncommon pathologies: variable myonecrotic syndromes
  34. Streptokinase
    • Bacterial enzyme  that dissolves fibrin clots 
    • promotes spreading of infection
    • secreted by: Streptococcus sp.

    localized--> gains critical mass--> breaks out of clot--> released anywhere within short distance of clot
  35. Pathogenicity/ Toxicity
    ID50--> infectious dose (of organisms) for 50% of the test population (Infectious Dose for 50%)

    LD50: lethal dose (of a toxin) for 50% of the test population (Lethal Dose for 50%)
  36. Exotoxins and Endotoxins
    gram positive have exotoxins

    gram negative bacteria have endotoxins
  37. Endotoxins

    - Source: __
    - Relation to Microbe: __
    - Chemistry: __
    • Source: gram -
    • relation: outer membrane (cell wall)
    • chemistry: lipid A of LPS
  38. Endotoxins

    Chemistry: __
    Chemistry: Lipid A (of LPS)
  39. Endotoxin

    - source
    -relation to microbe
    - chemistry
    - fever
    - neutralized by antitoxin (antibody)
    - LD50
    - Gram negative sp

    - Relation to microbe: outer membrane (cell wall)

    - Lipid A (of LPS)

    - Not neutralized by antitoxin

    - Relatively Large
  40. Exotoxin
    - the mechanism of action is __
    - the toxins are __

    relation to microbe:
    neutralized by antitoxin:
    • highly specific
    • species specific

    • source ??
    • relation: secreted by living cell
    • chemistry: protein
    • fever: no
    • neutralized by antitoxin: yes
    • LD50: small
  41. Virulence of Bacterial toxins

    - Typical endotoxin
    - Typical exotoxin
    endo: LD50 in mice= 200 micrograms

    exo: LD50 in mice= 2 x 10-5 micrograms
  42. Many __ genes are actually __ expressed in a __.
    • exotoxin
    • viral genes
    • lysogenized bacterial cell
  43. Bacteriums and their diseases:

    - __: diphtheria
    - __: strep throat
    - __: botulism
    - __: cholera
    Corynebacterium diphtheriae

    streptococcus pyogenes

    clostridium botulinum

    vibrio cholerae
  44. What is the first rule of any good infection?
    you gotta get in. If it can't get in, it can't cause disease
  45. Virulence is equivalent to __.
    the effectiveness of getting in
  46. Invasiveness must ask the questions?
    can the organism get in? If so, disease or no?
  47. What is the first rule of thumb for the invasion process?
    got to adhere (associate)

    does this by adhesins: work with proteoglycan receptors on the cell
  48. Endotoxins are released when __.
    cells die in gram negative bacteria
  49. Exotoxins are __. Secreted while __.

    Two components of exotoxins.
    species specific

    bacteria is alive

    one to bind and one to go in (shuts down protein synthesis)

    proteins sitting on genes