Leukocyte characterization

Inflammation involves various immune-system cells and numerous mediators. Recruitment of blood leukocytes characterizes the initiation of inflammatory response. The migrated or activated immune cells generate and release a variety of mediators that control the progression and resolution of information. Among the numerous inflammatory mediators are cytokines and lipid mediators. 

Ehrengruber, M.U., Deranleau, D.A. and Coates, T.D. (1996). Shape oscillations of human neutrophil leukocytes Characterization and relationship to cell motility. J Exp. Biol. 199, 741-747. 

These interactions involve adhesion proteins called selectins, which are found both on the rolling leukocytes and on the endothelial cells of the vascular walls. Selectins have a characteristic domain structure, consisting of an N-terminal extracellular lectin domain, a single epidermal growth factor (EGR) domain, a series of two to nine short consensus repeat (SCR) domains, a single transmembrane segment, and a short cytoplasmic domain. Lectin domains, first characterized in plants, bind carbohydrates... 

The largest numbers of integrins are members of the (31 integrins, also known as the very late antigen (VLA) subfamily because of its late appearance after activation. There are at least seven receptors characterized from this subfamily, each with different ligand specificity. Among the most studied include the 04(31 and a5 31 receptors. The leukocyte integrin a4 31 is a cell adhesion receptor that is predominantly expressed on lymphocytes, monocytes and eosinophils. 

S Molecular cloning and characterization of a novel 62 type of histamine receptor preferentially expressed in leukocytes. J Biol Chem 2000 275 36781. 

Imai T, Hieshima K, Haskell C, et al. Identification and molecular characterization of fractalkine receptor CX3CR1, which mediates both leukocyte migration and adhesion. Cell 1997 91 521-530. 

Oda, T., Morikawa, N., Saito,Y., Masuho,Y. and Matsumoto, S. Molecular cloning and characterization of novel type of histamine receptor preferentially expressed in leukocytes. /. Biol. Chem. 275 36781-36786, 2000. 

Channels associated with capacitative calcium ion entry have been characterized electrophysiologically. In leukocytes, the current associated with the depletion of intracellular Ca2+ stores is highly Ca2+-selective and, on the basis of noise analysis, is believed to involve minute single channels [16] (see Ch. 6). This is the calcium release-activated calcium current (ICrac)- In other cell types, currents with significantly different properties have been identified, including in some instances store-operated nonse-lective cation channels. These marked electrophysiological distinctions may be indicative of distinct channel types mediating capacitative calcium ion entry in different cell types. 

Macrocytic anemias are characterized by increased mean corpuscular volume (110 to 140 fL). One of the earliest and most specific indications of macrocytic anemia is hypersegmented polymorphonuclear leukocytes on the peripheral blood smear. Vitamin B12 and folate concentrations can be measured to differentiate between the two deficiency anemias. A vitamin B12 value of less than 150 pg/mL, together with appropriate peripheral smear and clinical symptoms, is diagnostic of vitamin B12-deficiency anemia. A decreased RBC folate concentration (less than 150 ng/mL) appears to be a better indicator of folate-deficiency anemia than a decreased serum folate concentration (less than 3 ng/mL). 

LO activity is found in a variety of mammalian cells, most notably leukocytes, with the enzymes from neutrophils and the rat basophilic leukemia (RBL-1) cell line being the most studied several have been purified and cloned [5]. 5-LO is a cytosolic enzyme which requires calcium, ATP and additional uncharacterized cell components for optimal activity. Characterization and kinetic studies with 5-LO enzymes are often difficult, because of self-inactivation and complex cofactor requirements. 

Leukemia a cancer of the blood or bone marrow characterized by abnormal proliferation of leukocytes. 

Puimonary reactions Pulmonary reactions characterized by acute dyspnea, hypoxemia, and interstitial infiltrates have been observed in neutropenic patients receiving amphotericin B and leukocyte transfusions. Separate the infusion as far as possible from the time of a leukocyte transfusion. 

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