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Due to their role in phagocytosis, macrophages are involved in many diseases of the immune system. For example, they participate in the formation of granulomas, inflammatory lesions that may be caused by a large number of diseases. Some disorders, mostly rare, of ineffective phagocytosis and macrophage function have been described, for example ...
Half-maximum stimulation is attained at about 100 nM. Stimulation of phagocytosis is obtained with polymorphonuclear leukocyte (PMN) cells from human, dog, rabbit and cow as well as with macrophages from the lung and peritoneal cavity of mice, and guinea pig and mouse bone marrow cells.
Dogs usually present with lethargy, asthaenia, anorexia, or mild pyrexia. Signs of platelet dysfunction such as petechiae or ecchymosis, epistaxis or rhinorrhagia and in severe cases with haematuria; gingival or ocular haemorrhages are used to identify and diagnose thrombocytopaenia. Up to half of dogs may present with splenomegaly. [2] [8] [1]
Overview of phagocytosis Phagocytosis versus exocytosis. Phagocytosis (from Ancient Greek φαγεῖν (phagein) 'to eat' and κύτος (kytos) 'cell') is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis.
Macrophages are diffusely scattered in the connective tissue and in liver (Kupffer cells), spleen and lymph nodes (sinus histiocytes), lungs (alveolar macrophages), and central nervous system (microglia). The half-life of blood monocytes is about 1 day, whereas the life span of tissue macrophages is several months or years.
These histiocytes are part of the immune system by way of two distinct functions: phagocytosis and antigen presentation. Phagocytosis is the main process of macrophages and antigen presentation the main property of dendritic cells (so called because of their star-like cytoplasmic processes).
Unbound phagocyte surface receptors do not trigger phagocytosis. 2. Binding of receptors causes them to cluster. 3. Phagocytosis is triggered and the particle is taken up by the phagocyte. Phagocytosis is the process of taking in particles such as bacteria, invasive fungi, parasites, dead host cells, and cellular and foreign debris by a cell. [22]
A siderophage is a hemosiderin-containing macrophage. Heart failure cells are siderophages generated in the alveoli of the lungs of people with left heart failure or chronic pulmonary edema, when the high pulmonary blood pressure causes red blood cells to pass through the vascular wall. [1] Siderophages are not specific of heart failure.