Path Pre-Unifieds Flashcards
AL Amyloid
Amyloid light chain. Usually associated with lambda B cell diseases. Primary systemic amyloidosis.
AA Amyloid
Amyloid associated non-ig protein from SAA. SAA is high in chronic inflammatory diseases, produced in liver. Chronic inflammation –> macrophage activation –> IL-1 and 6 –> liver cells –> SAA protein– >limited proteolysis, AA protein buildup.
Immunocyte dyscrasias with Amyloidosis
Deposition of AL or their fragments in extracellular spaces throughout body. Abnormal clones of B cells ie multiple myeloma. Excess Ig and light chains only (Bence Jones proteins).
Reactive systemic amyloidosis
Deposition of AA protein in EC space of most organs and systems. Used to be called secondary amyloidosis bc often associated with chronic inflamm processes. Usually secondary to autoimmune disease, neoplasms (hodgkins), and chronic skin infections. TBC, chronic osteomyelitis, bronchiectasis.
Hemochromatosis
Extreme iron overload, genetic. Cardiac failure, hepatic cirrhosis, and diabetes. Bronze like appearance “bronze diabetes”. Also increased risk of malignant tumours of liver (hepatocellular carcinoma)
Familial Systemic Amyloidosis
Buildup of AA or transthyretin (Mediterranean fever, neuropathies)
Familial Mediterranean fever
AR disorder of PMN function, AA deposits occur
Familial amyloidotic neuropathies
AD , many mutations in amyloidogenic proteins. Most common subtype is transthyretin mutation
Senile localized amyloidosis of Heart
Less severe, don’t really understand. Associated with transthyretin, often asymptomatic and discovered at autopsy.
Gouty mechanism
Urate crystal precipitation. (1) Activation of complement, neutrophil chemotax, phagocytosis, lysis of neutrophils, release of more crystals, lysosomal enzymes, tissue injury inflamm. (2) phagocytosis by macrophages, release of LTB4, PGI, free radicals - neutrophil chemotax, activation of inflammasome, release of IL-1B, secretion of chemokines and other cytokines, protases, tissue injury and inflamm.
Cell Injury: Lysosomes
Usually due to drugs and antibiotics. Can cause autophagy by activation of lysosomal enzymes with enzymatic digestion of cell components –> necrosis. Can cause incomplete degradation of phagocytosed material (lysosomes lose ability to degrade if lose enzymes).
Cell injury: mitochondria
Usually due to any agent that affects oxidative phosphorylation ie hypoxia, hypoglycemia. Lack of O2 as the final electron acceptor
Cell injury mechanisms leading to necrosis
Hypoxia, ischemia, decreased ATP –> necrosis. Increase in ROS from injurious stimuli, damage to lipids proteins and nucleic acids –> necrosis. Inflammation, releases toxic molecules, necrosis (or apoptosis)
Cell injury mechanisms leading to apoptosis
Mutations, cell stress, infections => Accumulation of mis-folded proteins in ER => apoptosis.
Radiation, other insults => DNA damage => apoptosis
Inflammation from infections, immuno disorders => toxic molecules => apoptosis (or necrosis)
Reversible Ischaemic injury
Impaired aerobic resp., decreased ATP, anaerobic glycolysis, glycogen depletion, lactic acidosis and nuclear chromatin clumping.
ATP deficiency –> energy loss –> cell membrane integrity –> failure of NA pump –> cel swelling and calcium influx –> Lactate accumulation (also leads to cell swelling) –> detachment of ribosomes –> blebs, myelin figures (cell membrane) –> mitochondrial swelling.
IRREV ischaemic injury
Severe vacuolization of mitochondria, damage of plasma membranes, swelling of lysosomes and MASSIVE Calcium influx, marked intracellular acidosis, ruptured lysosomal membrane, cell digestion and death. Inability of mitochondria to recover. Calcium influx denatures proteins and causes cell coagulation.
When is injury irreversible?
Mitochondria unable to recover after re-oxygeniation –> lloss of phospholipids –> damage to cytoskeleton –> O2 free radicals and lipid break products (ROS), influx of calcium fater re-ox with protein denaturation (coagulation of cells).
Free radical injury
Most affect cell membranes. Most common are activatd oxygen radicals (aging, chemical, infections, inflamm etc). Free radicals affect cell membranes by lipid peroxidation, and affect nucleic acids with mutations. Protective mechanisms = catalase and glutathione.
Chemical injury (direct or indirect)
Direct: mercury binds to protiens and cell membranes
indirect: by metabolic activation ie CCl4 –> Ccl3 in ER (irreversible fatty change)
Accumulation of lipid in cells (ER) because of lack of lipoproteins necessary for TAGs to leave the cell –> fatty liver.
Viral injury (cytopathic or cytolytic or oncogenic effect)
Cytopathic - rapid replication within cell, immune response, inflammation, and cell lysis
Often cell specific (receptors)
Also effects on cell skeleton–> multinucleation, inclusino bodies etc.
Apoptosis
Physiological usually. Cell shrinks. Eventual fragmentation of nucleus and cell–> apoptotic body –> phagocytized –> residual (acidophilic) body. NO INFLAMMATION.
Coagulative necrosis
Most common type. Ischaemic, coagulation of cells, loss of nuclei, denatured proteins. Acidophilic mass on H&E. Wedge shaped infarcts.
Liquefactive necrosis
Hydrolytic enzymes. Brain, bacterial infections.
Fat necrosis
Can occur anywhere there is fat. Dystrophic calcification, metastatic calcification. Release of lipases fro pancreas or inflammatory cells, FFAs plus calcium –> soaps. Chalky cheesy nodules deposit.
Caseous necrosis
TB. Combination of coagulative and liquefactive. Cheesy-milky. Eosinophilic (ie acidophilic, pink).
Gangrenous necrosis
affects limbs. Ischemia and infection. Dry or wet - wet once liquefactive (bacteria), infection of dry one.
Russel Bodies
Intracellular accumulation. Accumulation of Immunoglobulins in RER of plasma cells –> eosinophilic.
Mechanisms of intracellular accumulations
Abnormal metabolism (fatty liver, defect in protein folding, transport, lack of enzyme (lysosomal storage diseases, endogenous materials), ingestion of indigestible materials (exogenous, ie carbon pigment accumulation)
Endocervical metaplasia
Simple columnar to stratified squamous. Squamous metaplasia. Due to multiple kids, HPV, etc. Pap smear to test.
Calorie restriction as a counteractant to aging
Decrased insulin, IGF signaling, decreased TOR => altered transcription => increased DNA repair, increased protein homeostatis
Vascular permeability mechanisms
- Endothelial cell contraction - histamine mediated. Short lived, reversible (15-30 mins). Small venules
- Junctional retraction - cytokine mediated (produced in inflammation). 4-6 hours post injury, lasts 24 hours
- Direct endothelial injury *most important
Endothelial cell necrosis, more severe injuries, starts early/lasts for days. Immediate and sustained, delayed. Affects venules and capillaries. Trauma, autoimmune, allergic rxns.
Requirements of engulfment
Require energy, calcium, and magnesium to form pseudopods. Engulfment is thus an extremely energy consuming process
Phagocytosis complications
- Regurgitation: infection by very powerful bacteria. Enzymes pour out before the macrophage can wrap around the bacteria. Kills white cells, being overcome.
- Frustrated phagocytosis: Phagocytes working but tissue won’t let them work - ie endothelial cells in glomerulus, surface endothelium coated by opsonins, but endothelial cells stuck on BM - can’t ingest a stuck endothelium, macrophages get overexcited. Enzymes pour out, kill out endothelial cells, more opsonins, etc.
- Cytotoxic release - phagocyte gets overexcited, misses steps, bursts.
PAF Platelet Activating Factor
Released by endothelial cells and inflammatory cells, damaged tissue cells. Powerful VASODILATOR, increases PERMEABILITY, stimulates platelets, inflamm, and endothelial cells. Aggregation of platelets at site of injury, chemotactic functions.
Vasoactive Amines
Serotonin (from platelets only), Histamine (from platelets and mast cells, basophils). Vasodilation, and increased vascular permeability (VENULES only).
Endothelins
Peptide produced by endothelial cells. powerful VASOCONSTRICTOR.
Agents for histamine release from mast cells tfc
Physical trauma, cold Immunological (igE) C3a and C5a (anaphylatoxins) histamine releasing factors from PMNs, monocytes and platelets IL-1
Bradykinin
HMWK => pre-kallikrein => kallikrin, converts kininogen to Bradykinin, increased vascular permeability, vasodilation, PAIN, contraction of smooth muscle. Early phases of inflammation only.
Granulomatous inflammation
Type of chronic inflammation (other type is non-specific). Formation of a granuloma - central focus (usually necrotic), surrounded by epitheloid cells, which are surrounded by a rim of lymphocytes and or plasma cells. Older granulomas can have a ring of fibroblasts or CT. Often giant cells (multinucleated, histiocytic or monocytic origin) are present among inner cells.
Common causes of granulomatous Inflammation
Characteristic of TB, syphilis, cat scratch disease, fungal, protozoan, persistent foreign body inflamm, rheumatic fever (aschoff body), rheumatoid arthritis (subcutaneous nodules), sarcoidosis, granuloma annular of skin.
Types of inflammation , increasing severity
Serous (albumin in exudat, blisters, ascites, etc), fibrinous (worse leakage ie fibrin. Serosal surfaces), Suppurative (pus, liquefactive, necessitated by bacteria, ie cocci etc), sanguinous (rich in RbCs, serious vascular injury, tuberculous pleuritis, tumors).
Fibrinous Inflammation
More severe than serous, significant vascular damage, large molecules pass: fibrinogen, eg. rheumatic fever (bread and butter pericarditis), pneumococcal pneumonia. Fibrin is acidophilic.
Suppurative Inflammation
Liquefactive necrosis by bacteria => pus. Caused by pyogens ie Staph, pneumococcus, meningococcus, gonococcus, e. coli, some non-haemolytic strep.
Pseudomembranous inflammation
Ie pseudomembranous colitis (often with c diff, elderly taking antibiotics). On mucosal surfaces, mucous mixed with bacteria and neutrophils. Produced by powerful necrotizing toxin ie diptheria. Formation of pseudomembrane = fibrin, necrotic epithelium, WBCs.
Fibronectin
Multiple roles in wound healing. Glue-like effect, intermediate filaments, chemotactic, migration and organization of cells, release fibroblast GF from macrophages.
Amyloid
Proteinaceous, stain blue with iodine. Glassy pink H&E, salmon colour on congo red, apple green birefringence. EM: non-branching fibrils (up to 6), plus non-fibrillary component (P component)
Systemic amyloidosis
Immunocyte dyscrasias (excess of Ig and BJ, AL), reactive systemic (AA protein in chronic inflam, skin, hodgkins, TB, RF), Hemodialysis (B2 microglobulin), Familial diseases (ie mediterannean fever AR , AA deposits; familial amyloidotic neuropathies AD
Localized amyloidosis
Diabetes (deposits in islets), senile cardiac amyloidosis (transthyretin, asymptomatic), senile cerebral amyloidofsis (alzheimer’s disease)
Carbon as a pigment
most common pollutant, accumulats in tissue (lungs lymph = anthracosis. Phagacytosed by alveolar macrophages. Often with other pollutant in industry ie silica asbestos
Lipofuscin
Wear & tear, breakdown pdt of cell membrane, normal in small amount. Visible in liver, heart, brain. Lysosomes of cells. Intracellular, perinuclear accumulation. Yellowish brown
Bile
Bilirubin, bile salts, lipids. Pigment derived from breakdown of old RBCs, excess pdn or inability to excrete makes it visible. Both INTRA and EXTRAcellular. In cells and in the ducts around cells.
Hemosiderin
Breakdown of Hemoglobin, golden brown H&E. Blue with prussian blue, stored in spleen, liver, bone marrow. Excess Fe in cells: hemosiderosis
Anaplasia
Lack of differentiation, term used in invasive neoplasm
Pathways of metastasis
- Seeding via body cavities (peritoneal cavity most common ie ovarian carcinoma). Also pericardial, pleural, subarachnoid cavities 2. Lymphatic spread - most common initial dissemination of carcinomas, follows natural drainage. 4. Hematogenous spread - favoured by sarcomas, liver and lungs are most frequent secondary sites as all PORTAL areas drain to liver and all CAVAL areas drain to the lungs.
MDM2
Inhibitor of p53 - in normal, non-stressed cells who don’t need p53. But overexpression leads to resistance of apoptosis, cancerous