Micro Test 4: Slow Viruses

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  1. Associated with virus:
    Subacute Sclerosing Panencephalitis (SSPE)?
    Progresive Rubella Panencephalitis?
    Progressive Multifocal Leukoencephalopathy (PML)?
    • SSPE- Measles virus
    • PRP- Rubella Virus
    • PML- BK, JC Virus
  2. Human Diseases
    • Kuru
    • Creutzfeldt-Jakob Disease
    • Gerstmann-Straussler-Scheinker Disease (GSSD)
    • Fatal Familial Insomnia (FFI)
  3. The measles virus from SSPE pts. differs from
    the wild type measlres virus and are not derived from vaccine strains in the MMR vaccine (point mutations, deletions, defective interfering particles)
  4. Most mutations of the measles virus in SSPE had mutations in the
    M gene (encoding the Matix protein)
  5. SSPE directly invades
    brain cells -> brain inflammation
  6. SSPE is more common among patients who had measles at what point in their life?
    Before age 2
  7. Interval btw measles and development of SSPE
    ~7 years
  8. SSPE involves
    White and gray matter or cerebral hemispheres and brain stem
  9. Involves white and gray matter of cerebral hemispheres and brain stem
  10. Is SSPE a demyelinating disease?
    No, it causes the destruction of all brain tissue elements, not just myelin

    *Large quantities of defective virus in brain
  11. 2 things in light microscopy of SSPE
    • Perivascular Cuffing
    • Nuclear Inclusions
  12. Perivascular Cuffing
    Will see perivascular and diffuse infiltrates of lymphocytes, plasma cells, w/ destruction of nerve cells
  13. 3 Stages of SSPE
    • Stage 1:  Intellectual decline (poor school performance, abnormal behavior)
    • Stage 2:  Seizures, visual impairment, continued intellectual decline
    • Stage 3:  Decorticate state, blind, rigidity
  14. Optic nerve damage and damage to the retina are characteristic of
  15. SSPE: Tests
    • EEG
    • Serum Ab titer (showing elevation titer to measles)
    • Spinal tap
  16. SSPE: Tx
    No cure; can slow progression of disease with Isopinosine and IFN-a injected directly into brain

    SSPE is always fatal
  17. Progressive Rubella Panencephalopathy follows rubella by
    10-20 years
  18. Increasingly severe neurologic deterioration in patients with previously stable congenital rubella
    Progressive Rubella Panencephalopathy (PRPE)
  19. Pathology of PRPE (very similar to SSPE)
    • Subacute encephalitis involving white and gray matter
    • Destruction of all brain tissue elements, not demyelinating
  20. PRPE:  Clinical Manifestations
    • Spasticity, ataxia, seizures
    • Intellecutal deterioration, progresses to death
  21. PRPE:  Preventable?
  22. Major goal of rubella vaccination
    Prevention of birth defects in babies infected in uteo

    All women of child-bearing age should be re-vaccinated (vaccine is contraindicated in women who are pregnant since the vaccine is a live, attenuated virus)
  23. Due to latent infxn of polyomaviruses that may be reactivated in immunocompromised patients.
    Progressive Multifocal Leukoencephalopathy (PML)
  24. Time of Onset of PML for pregnant women
     3rd trimester
  25. Usually appears in hypergic adults, majority of pts. btw 40-70 yrs. old
  26. 1/2 of the people who have PML also have had
    Lymphoproliferative or Myeloproliferative neoplasms (hodgkin's disease, CLL)
  27. Rapidly progressive focal neurologic deficits including hemiparesis, visual field deficits, and cognitive impairment

    *Can also have aphasia, ataxia, and/ or cranial nerve deficits
  28. PML:  Time from symptoms appearance until death
    2-4 months
  29. PML shows single or multiple confluent lesions w/o mass effects that are seen most frequently in the
    Parietooccipital white matter

    *Subcortical gray matter or spinal cord may be involved, but this is rare
  30. Can ressemble lymphoma, toxoplasmosis, or HIV encephalitis
  31. PML:  Nuclear inclusions seen in

    *Astrocytes only have inclusions rarely
  32. PML prognosis
    • PML progresses to severe dementia and death over several months
    • Progression is more rapid in AIDS-associated PML
  33. Spongiform degeneration of neurons
    Severe astrocytic cliosis out of proportion with the degree of cell loss
    Amyloid plaque formation
  34. Neuropathological characteristics of Transmissible Spongiform Encephalopathies
    • Spongiform degeneration of neurons
    • Severe astrocytic cliosis out of proportion with the degree of cell loss
    • Amyloid plaque formation
  35. Characteristics of TSES
    • Long incubation
    • No inflammatory response
    • No cytopathic effec tin infected cells in vivo
    • No IFN production
    • No antigenicity
    • No virus-like particles or inclusion bodies
    • No demonstrable nucleic acid
  36. Agents that affect _______ inactivate prions
    Proteins (NOT DNA)
  37. Prion consists of
  38. Prions replicate via
    a crystallization event
  39. Major infectious materia in prion diseases
    PrPSC Protein

    *Normal proteins are designated as PrPc
  40. PrPC synthesized in
    PRPC synthesized in ER

    PrP(SC) resistant to phospholipase
  41. Refers to the prolongation of the incubation time when prions from one species are transmitted to another species
    Species Barrier
  42. Classic vs. Variant CJD:  Mediate age at death
    • Classic= 68 years
    • vCJD= 28 years
  43. Classic vs. vCJD:  Median duration of illness
    • Classic= 4-5 months
    • vCJD= 13-14 months
  44. Classic vs. vCJD:  Period sharp waves on electroencephalogram
    • Classic= often present
    • vCJD= often absent
  45. Classic vs. vCJD:  Plvinar sign on MRI
    vCJD:  Present in 75% of cases
  46. Classic vs. vCJD:  Presence of "florid plaques" on neuropathology
    • Classic= Rare
    • vCJD= Present in large numbers
  47. Classic vs. vCJD:  Presence of agent in lymphoid tissue
    • Classic= Not readily detected
    • vCJD= Readily detected
  48. Classic vs. vCJD:  Increased glycoform ratio on immunoblot analysis of protease-resistance prion protein
    • Classic= Not reported
    • vCJD= Marked accumulation of protease-resistance prion proteins
  49. vCJD strains same or different the CJD?
Card Set:
Micro Test 4: Slow Viruses
2013-02-09 06:09:17
Micro Test Slow Viruses

Micro Test 4 Slow Viruses
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