1. Cell Injury

1. Cell Injury

Prepladder

Basic Concepts

55% | 47% | 25s /Q

  • Signalling pathways that trigger hypertrophy activate transcription factors such as
    • GATA 4
    • Nuclear factor of Activated T-cells (NFAT)
    • Myocyte Enhancer Factor 2 (MEF2)
  • Glutaraldehyde is the most commonly used fixative for electron microscopy
  • 10% neutral buffered Formalin is most commonly used fixative for light microscopic
  • Lipids in the tissue are detected by Oil Red O (histologic stain) #histology
  • Mallory bodies are composed of interwoven bundles of cytoskeletol intermediate filaments (cytokeratins)
  • The pancreas of fetus (of diabetic mothers) may undergo hyperplasia due to increased demand. This is because islets of pancreas have proliferative capacity during fetal development
  • Hydropic swelling reflects the acute, reversible cell injury Plasma membrane sodium transport is impaired due to unavailability of ATP
  • Cellular ageing is inflenced by:
    • DNA damage -> causes mutatuin
    • Telomere shortening -> cellular replication reduced -> cell loss
    • Defective protein homeostasis -> Both normal folding and degradation of misfolded proteins are impaired with aging
    • Dysregulated nutrient sensing -> Mediators may be reduced IGF-1 signaling and increase sirutins

Reversible cell injury

48% | 57% | 19 s/Q

  • Breast does not undergo both hypertrophy and hyperplasia during lactation -> prolactin and estrogen only cause hypertrophy

    • However during pregnancy and puberty it does undergo both
  • In Fenton reaction, iron is converted from ferrous to ferric form, and a hydroxyl radical is generated

Assessment of a Fenton reaction driven by insoluble tannins from pine bark in treating an emergent contaminant - ScienceDirect

  • Pleomorphic adenoma are the most common salivary gland neoplasms

    • Mixed tumor - Epithelial + Mesenchymal component
    • Warthin tumor is the 2nd most common neoplasm
    • Mucoepidermoid carcinoma is the most common primary malignant tumor of salivary glands
  • Ground glass hepatocytes are seen in chronic hepatits B

    • Autoimmune hepatitis features
      • Autoantibodies
      • IgG level increased (1.1x)
      • Histology of liver
        • In interface hepatitis: Lymphocytic/lymphoplasmacytic infiltrates in portal cells and extending in the lobule
        • Emperipolesis: Active penetration by one cell into another and through a larger cell (cell within a cell)
        • Hepatic rosette formation
      • Absence of viral hepatits
  • Kayorrhexis is a feature of necrosi (irreversible cell injury)

  • Inflammasome is mediated by IL-1β

    • It’s a cytosolic multiprotein complex consisting of NLRP-3 sensor, an adaptor and inactive Caspase-1 enzyme
    • It’s triggered by NOD-like receptors (NLRs) that sense the ingested microbial particles
    • NLRs signals activate IL-1β, cleaving it from precursor form -> biologically active form

Irreversible Cell Injury/Necrosis

77% | 65% | 21 S/Q

  • Micro-RNAs are non-coding RNAs 21-30 nucleotides in length
  • Metastatic calcification is prone to organs that have an internal alkaline component
  • Cellular maturation shows abnormal pattern in dysplasia which is preneoplastic
  • Abscess is a clear example of liquefactive infarct as a cavity is formed by liquefaction of solid tissue
  • Ghon’s complex is a lesion seen in the lung that is caused by tuberculosis
  • Nuclear features are hallmark of necrosis, other features like cytoplasmic swelling can be of both
  • Extracted DNA from apoptotic cells gives a ladder pattern in electrophoresis
  • Pyogenic Infection: infection that produces pus -
  • Pyroptosis causes highly inflammatory form of death

Apoptosis

87% | 84% | 19s /q

  • Caspases exist as inactive proenzymes/zymogens
  • Platlet degranulation is a component of primary hemostasis
  • Councilman body - Apoptotic hepatocytes
  • FasL is not involved in INTRINISC PATHWAY
  • LC3 is involved in Autophagy
  • Efferocytosis: Apoptotic cell phagocytposis -occurs because of Cq1 coated that attracts macrophages

Free Radical Injury

  • SOD (Superoxide Dismutase) protects from production of free radicals
#histology