Clinical and biochemical effects of endotoxins


Lipooligosaccharide (LOS): Short chain endotoxin; found in N. meningitidis bacteria that cause meningococcemia.


Lipopolysaccharide (LPS): long chain endotoxin; the most common form found in Gram-negative bacteria.


Lipopolysaccharide binding protein (LBP): An acute phase plasma protein that binds to endotoxin. The LPS-LBP complex binds to the CD14 receptor on macrophages, triggering cytokine release and initiating the inflammatory cascade.


Lipid A: The lipid portion of endotoxin that is responsible for its toxicity by binding to LBP and inducing the inflammatory cascade.


Gram-negative bacteria: Constitute the primary microbial population in the intestines and are therefore a potentially complicating factor in other infections as well as in trauma and surgery (intestinal translocation).


Intestinal translocation: The transfer of bacteria or their break-down products, including endotoxin, across the mucosa of the gastrointestinal tract to the systemic circulation. When normal host mechanisms which modulate the process fail, bacteria and/or their endotoxins may trigger a systemic inflammatory response.


Complement, complement cascade: a system of at least 15 naturally occurring plasma proteins (complement proteins) which play a role in host defense and mediate a number of inflammatory reactions.


Cytokines: Signaling chemicals involved in inflammation, such as interleukins (e.g. IL-1, IL-6, interferons, and tumor necrosis factor (TNF). Cytokines are released by macrophages, lymphocytes, and other cells in response to pro-inflammatory stimuli such as infectious organisms or endotoxin.


Multiple organ dysfunction Syndrome (MODS): in acutely ill patients altered function of multiple organs - such as the kidneys, lungs, liver, and central nervous system - as defined by the inability to maintain normal homeostasis in the absence of medical intervention. Primary MODS is the result of a direct insult to the organs. Secondary MODS is the consequence of the systemic inflammatory response.


Sepsis: systemic response to infection; a syndrome characterized by a culture-documented infection and two or more of the following signs and symptoms: Hyper- or hypothermia, tachycardia, hyperventilation and leukocytosis or leukopenia.


Septic shock: septic shock refers to the most severe form of sepsis, characterized by refractory hypotension, clinical evidence of organ hypoperfusion, and/or organ dysfunction in the presence of a documented infection.


Systemic Inflammatory Response Syndrome (SIRS): the systemic inflammatory response, to a variety of severe clinical insults. Characterized by fever or hypothermia, tachycardia, tachypnea, abnormal white cell count. Differs from sepsis only in that the term SIRS is used in the absence of a documented infection.


Cascade: a complex sequence of events characterized by multiple positive and negative feedback loops of biologically active molecules (such as cytokines, complement, and coagulation factors). Each component of the cascade is activated and/or suppressed by previous components, and in turn activates and/or suppresses later components.


Inflammation: a multifactorial cellular and humoral host defense response classically characterized by redness, swelling, warmth, and pain when confined to a local area. Systemic activation of the inflammatory response, however, can manifest as fever, shock, organ dysfunction, and even death.

Inflammatory cascade: the specific systemic cascade induced in response to infection or exposure to infectious organisms. Clinical signs range from none through fever, malaise, hypo- or hypertension, and tachycardia, to shock, multiple organ failure and death.


Coagulation cascade: the series of tissue-based and circulating molecules which are activated in sequence to cause blood clotting (coagulation).

Endotoxin (Lipopolysaccharide, LPS): Lipopolysaccharides are complex molecules composed of "fat plus many sugars". The LPS molecule is a structural part of the cell wall in Gram-negative bacteria. Endotoxin initiates a potentially catastrophic inflammatory cascade that can lead to sepsis, shock, organ failure and death.


Bacteremia: literally "bacteria in the blood"; a bacterial infection originating in or spreading to the blood stream.


Endotoxemia: the detectable presence of endotoxin in the blood stream.


Disseminated intravascular coagulation (DIC): a syndrome of generalized activation of coagulation factors, leading to clinical manifestations of inappropriate clotting, bleeding and shock.


CD14: a receptor produced by monocytes and displaced on cell membranes as well as being shed into the blood stream. The CD14 molecule binds to the LPS-LBP complex and initiates the inflammatory cascade.


Les Adrets de l`Estérel

September 20, 2014


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