Robbins Chapter 2 - Inflammation Flashcards
What are the five cardinal signs of inflammation?
Rubor = redness Tumor = swelling Calor = heat Dolor = pain functio laesa = loss of function
Describe exudate
Exudate is an acidic fluid which is high in protein content, cell debris, and has a high specific gravity. It is the result of vasodilation and increased vascular permeability.
Note: may become purulent when it contains a lot of neutrophils
Describe transudate
Transudate is an alkaline fluid with low specific gravity, low protein content, and no cellular debris. It is the result of increased hydrostatic pressure in the capillaries.
What is the immediate transient response?
immediate changes in vascular permeability due to the actions of NO and histamine.
What is the delayed proloonged response?
Same response as immediate but occurs later and lasts longer
What is the immediate prolonged response?
An immediate response of the vascular membrane, but remains for longer duration due to damage to endothelial cells
What do serous, sanguinous, purulent, and chylous mean in describing an effusion? What is an effusion?
Serous = yellow/clear fluid Sanguinous = blood Purulent = pus chylous = milky, white
An effusion is the occurence of edema with in a potential or pre-existing space.
What are the chemical mediators which cause contraction of endothelial cells?
Histamine, bradykinin, leukotrienes (LTC4, D4, E4), and substance P
What process are vesiculovacuolar organelles involved in? What factor mediates this process?
Transcytosis - movement of fluid and proteins through the endothelium occurs through a channel of connected vesiculovacuolar organelles.
Mediated by the expression of VEGF.
Describe the changes seen in the lymphatic system in response to inflammation.
Lymph flow will increase in the inflammatory response due to edema. Vessel proliferation is also mediated by VEGF and VEGFR-3.
Describe the process of leukocyte recruitment from the vessel lumen to the interstitium of the injured tissue.
The immediate response of histamine and NO cause slowing of blood flow resulting in margination of the leukocytes, specifically neutrophils. Leukocytes are stimulated by local factors to express selectins to initiate rolling adhesion. Leukocytes will come to a complete stop through the expression of integrins. Diapedesis results via PECAM-1. Chemotaxis occurs along the ECM through the expression of endogenous and exogenous mediators.
Describe L-, E-, and P-selectins. What stimulates their expression?
L-selectin is expressed by leukocytes and binds to GlyCam-1 and CD34. It is responsible for homing of leukocytes to lymphatic tissues.
E-selectin is expressed by endothelial cells and binds to sialyl-lewis x-modified proteins.
P-selectin is expressed by platelets, in addition to endothelial cells, and also binds an x-modified protein.
E-and L-selectin expression is stimulated by TNF and IL-1.
P-selectin is stored in weibel-palade bodies, the redistribution of which is caused by histamine, thrombin, and PAF.
What are two clinically significant signs of adhesion molecule deficiency?
Recurrent bacterial infections along side lack of purulent lesions.
Describe the expression and binding of integrins.
Integrins are expressed by leukocytes in response to the expression of TNF and IL-1. VLA-4 and LFA-1 bind to VCAM-1 and ICAM-1, respectively, on the endothelium.
Describe diapedesis in reference to location and mechanism
Typically occurs in the post-capillary venules. Mediated by the molecules PECAM-1 (CD34) and CD99. After traversing the endothelium collegenases are secreted to allow movement through the basement membrane.
Describe chemotaxis of leukocytes in the interstitium
Leukocytes adhere to the ECM through the action of integrins and CD44.
Exogenous (f-met) and endogenous (cytokines, complement, and eicosanoids) mediators bind GPCRs on the cell.
Receptor binding causes increase in calcium and the polymerization of actin at the leading edge of the cell. At the tail edge myosin filaments localize. Leukocytes move through the extension of filopodia.
What are the specific exceptions (3) discussed in class to the normal pattern of leukocyte infiltration?
Pseudomonas - infiltrate is continuously dominated by neutrophils
Viral Infections - dominated by lymphocytes
Hypersensitivity reactions - dominated by eosinophils
What do TLR’s recognize and how do they transduce their signals? What is the general result of signal transduction?
TLRs recognize bacterial LPS and proteoglycans, and viral dsRNA
Transmit their signal through Tyrosine kinase-associated receptors.
End result is the production of microbicidal agents and cytokines by activated leukocytes
What do GPCRs recognize and how do they transduce a signal? What is the end result of receptor binding?
GPCRs will bind f-met, chemokines, PAF, leukotrienes, prostaglandins, and C5a
Transmit signal through activation of g-proteins
Causes cell migration and production of microbicidal agents by neutrophils and macrophages.
Describe the action of opsonins and how they are detected (3).
Opsonins coat the surface of microbes to signal phagocytosis.
IgG bound to a microbe can also bind to the FCγRI on phagocytes.
C3b binds microbes and the C1R on phagocytes
Mannan-binding lectin will also stimulate opsonization.
What is the major macrophage-activating cytokine and what cells produce it?
IFN-γ
Produced by NK cells and Antigen-activated T lymphocytes
What are the three ways a phagocytic cell binds to an object targeted for phagocytosis?
Mannose receptor - binds to mannose and fucose residues of glycoproteins and glycolipids.
Note: Host cells have sialic acid and are not recognized.
Scavenger receptor - binds microbes and modified LDL particles
Osponin receptors
What enzyme is responsible for the production of superoxide anion and where does this production occur in the cell?
Multicomponent (phagocyte) oxidase is responsible for rhe produciton of superoxide anion in the lysosome.
Describe the H2O2-MPO-halide system
Hydrogen peroxide is formed from the dismutation of superoxide anions. MPO is found in azurophilic granules of neutrophils. MPO can create hydroxyl radicals or hypochlorite in the presence of halides.
Note: hypochlorite is the most potent antimicrobial ROS
What is a byproduct of the production of NO and superoxide
NOS produces NO which can react with superoxide anions to form peroxynitrite
Describe the etiology, pathogenesis, and manifestations of Chediak-Higashi Syndrome.
Due to a mutation in the LYST gene lysosomal trafficking is dysfunctional leading to the inability of phagosomes to fuse with lysosomes.
Albinism results from abnormalities in melanocytes.
Recurrent infections due to giant granules in lymphocytes.
Nerve defects
Dense bodies in platelets causing bleeding disorders.