USMLE REVIEW

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USMLE REVIEW

• Rae Adams
• Monday Feb 20th
• Pgs 202-205

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Nosocomial Infections
 
 

• Those acquired while in a hospital or
  hospital-like setting.

 
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Nosocomial Infections

• Newborn Nursery Cradles and Rattles
• CMV
• RSV

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Nosocomial Infections

• Urinary Catherization PEE
• ProtEus mirabilis
• E. coli

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Nosocomial Infections

• Respirtory Therapy Equipment
• Pseudomonas AIRuginosa

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Nosocomial Infections

• Renal Dialysis Unit (Dialysis uses Blood)
• HBV

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Nosocomial Infections

• Hyperalimentation
• Candida albicans

• Water Aerosols
• Legionella

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Infections dangerous in pregnancy

• Toxoplasma
• O
• Rubella
• CMV
• HSV/HIV
• E
• Syphilis

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Bug Hints

• S. aureus SEAP
• Surgical wounds, Empyema, Abscess, Pus

• Clostridium perfringens TOW
• Traumatic Open Wound

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Bug Hints (cont.)

• Pediatric Infections Kids love the word HI
• Haemophilus Influenzae

• Pasteurella multocida Animals live in a pasture
• Dog or Cat Bites

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Bug Hints (cont.)

• Pseudomonas AIRuginosa
• Presume when AIR or burns involved
• (Pneumonia in CF or burn infections

• Actinomyces israelii
• Branching rods in oral infections
• Think Jewish nose and mouth
• oral infections

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Bug Hints (cont.)

• Group B Strep
• MeninGitis/Sepsis in newborns

• Klebsiella
• Currant jelly sputum
• (Thick, bloody, mucoid sputum)

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Immunology
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Antibody Structure
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Antibody Function
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Opsonization

• Opsonization Coating of the surface of a
  pathogen with any molecule (antigen) that makes
  it more readily ingested by phagocytes

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Neutralization

• Neutralization mechanism by which antibodies
  binding to sites on pathogens prevent growth of
  the pathogen or entry into cells.
• Neutral no positive (growth) and no negative
  (death)

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Complement Activation

• Complement Activation the initiation by
  pathogens of a series of reactions involving the
  complement components of plasma, leading to death
  and elimination of the pathogen.

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Ig Epitopes

• Allotype Ig epitope that differs among members
  of the same species. Can be on light or heavy
  chain
• Different alleles of the same C-region
• No functional change (b/c not in variable region)
• Example (IgG and IgG)

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Ig Epitopes

• Isotype Ig epitope common to a single class of
  Ig (5 classes determined by heavy chain)
• Different in constant region due to use of
  different C-region gene segments
• Isotypeiso (same). Common to same class
• Example (IgG and IgA)

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Ig Epitopes

• Idiotype Ig epitope determined by
  antigen-binding site
• Different CDR (Complementarity-Determining
  Regions)
• Idiotypeidio (unique).
• Change in function (due to change in
  hypervariable region)
• Example (specific for a given antigen)

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Immunoglobin Idiotypes

• Ig GAMED
• IgG 2 response most abundant fixes
  complement crosses placenta opsonizes bacteria,
  neutralizes bacteria toxins
• IgA Prevents attachment of bacteria and viruses
  to mucous membranes does not fix complement
  found in secretions picks up secretory component
  from epithelial cells before secretions
• IgM 1 response fixes complement does NOT
  cross placenta antigen receptor on surface of B
  cells and in serum
• IgE Mediates immediate (Type I)
  Hypersensitivity by inducing release of
  mediators from mast cells and basophils when
  exposed to an allergen mediates immunity to
  worms lowest concentration in serum
• IgD Dont know found of surface of many B
  cells and in serum

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Major Histocompatibility Complex IMHC I

• Consists of 3 Class I Genes (A, B, C)
• All nucleated cells have MHC I proteins
• MHC I antigen loading occurs in RER (viral
  antigens)
• Class I 1 polypeptide with B2 microglobulin

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Major Histocompatibility Complex IIMHC II

• Consists of 3 Class II Genes (DP, DQ, DR)
• ANTIGEN-PRESENTING CELLS (macrophages and
  dendritic cells) have MHC II proteins
• MHC II antigen loading occurs in acidified
  endosomes
• Class II 2 polypeptides, and alpha and beta
  chain
• Class II are the main determinants of organ
  rejection

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Differentiation of B and T cells
IL-2
Activated cytotoxic (CD8) cells
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Differentiation of B and T cells

• TH1 cells (produce IL-2 and IFN gamma) activate
  macrophages (increase killing efficiency of
  intracellular bacteria) and Tc cells
• TH2 cells (produce IL-4 and IL-5) help B cells
  make antibody (B-2nd letter of the alphabet)

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Major Function of B T cells
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Adjuvants

• ADJUVANTthat which aids another
• Adjuvants nonspecific stimulators of the immune
  response but are NOT immunogenic by themselves.
• Adjuvants are given with a weak immunogen to
  enhance response.
• Human vaccine contain aluminum hydroxide or lipid
  adjuvants.