Leucocytes

Leucoanthocyanins Leuco azomethines Leuco bases Leucocytes... 

Interferons (lENs) (52,53), a family of species-specific vertebrate proteins, confer nonspecific resistance to a broad range of viral infections, affect cell proliferation, and modulate immune responses. AH three principal interferons, a-interferon (lEN-a) produced by blood leucocytes, P-interferon (lEN-P) by fibroblasts, and y-interferon (lEN-y) by lymphocytes, also have antiviral activity. The abiUty of interferons to inhibit growth of transplantable and carcinogen-induced tumor led to research showing the direct antiproliferative and indirect immune-mediated antitumor activities (see Chemotherapeutics, anticancer). IENs have been found to be efficacious in certain malignancies and viral infections, eg, hairy cell leukemia (85% response) and basal cell carcinoma (86% response). However, the interferons do have adverse side effects (54). 

Aplastic anemia and leukemia are not the only health effects ascribed to benzene exposure. A number of recent studies have associated benzene exposure with chromosomal changes (aberrations) (118). Other studies have shown abnormalities in porphyrin metabolism and decrease in leucocyte alkaline phosphatase activity in apparendy healthy workers exposed to 10—20 ppm benzene (119,120). Increases in leukoagglutinins, as well as increases in blood fibrinolytic activity, have also been reported and are believed to be responsible for the persistent hemorrhages in chronic benzene poisoning (121,122). 

Leoko-phan, m. leucophane. -plast, n. (a kind of) adhesive plaster, -verbindung, /. leuco compound. -zyt, n. (Physiol.) leucocyte, -zytenzahl, /. leucocyte count, -zytose, /. leucocytosis. 

Lymph-gefass, n. lymphatic vessel, -korper-chen, n. lymph corpuscle, leucocyte, lyo-pbil, a. lyophile, lyophil(ic). -phob, a. lyophobe, lyophobic. -trop, a. lyotrope, lyotropic. 

A B lymphocyte is a specific type of white blood cell (leucocyte) derived from bone marrow stem cells. Each B lymphocyte expresses an immunoglobulin (antibody) specific for a particular antigen. Following antigenic stimulation, a B lymphocyte may differentiate and multiply into plasma cells that secrete large quantities of monoclonal antibody. 

Basophils constitute a subgroup of circulating blood cells (leucocytes). In many aspects they resemble... 

The human leucocyte antigen (HLA) system is the general name of a group of genes in the human major histocompatibility complex (MHC) region on human chromosome 6 (mouse chromosome 17) that encodes the cell-surface antigen-presenting proteins. 

Genes encoding particular class II Human Leucocyte Antigens (HLA) are among candidates for involvement in predisposition to RA. This discovery came about with the observation that 60- 70% of Caucasian patients with RA are HLA-DR4 positive by... 

Lackie, J.M. (1982). Aspects of the behavior of neutrophil leucocytes. In Cell Behavior (Bellairs, R., Curtis, A., Dunn, G., eds.), Cambridge University Press, Cambridge. 

H, Ransohoff RM (2003) Chemokine receptors on infiltrating leucocytes in inflammatory pathologies of the central nervous system (CNS). Neuropathol Appl Neurobiol 29 584-595... 

Roxithromycin has similar in vitro activity to erythromycin but enters leucocytes and macrophages more rapidly with higher concentrations in the lysosomal component of the phagocytic cells. It is likely to become an important drug against Legionella pneumophila. Clarithromycin is also of potential value. 

Type I interferons. These are acid-stable and comprise two major classes, leucocyte interferon (Le-IFN, IFN-a) released by stimulated leucocytes, and fibroblast interferon (F-IFN, FN-/3) released by shmulated fibroblasts. 

Tests have been published for determining toxicity towards leucocytes. Evaluation on the infected chorioallantoic membrane of hens eggs was suggested as being a useful method of testing potential wound disinfectants. 

The monocytes, which constitute about 5% of the total blood leucocytes. They migrate into the tissues and mature into macrophages (see below). 

The neutrophils (also called polymorphonuclear leucocytes, PMNs), which are the professional phagocytes of the body. They constitute >70% of the total leucocyte population, remaining in the circulatory system for less than 48 hours before migrating into the tissues, in response to a suitable stimulus, where they phagocytose material. They possess receptors forFc and activated C3 which enhance their phagocytic ability (see later in chapter). 

Proteins produced by virally infected cells have been shown to interfere with viral replication. They also activate leucocytes that can recognize these infected cells and subsequently kill them. These leucocytes are known as natural killer (NK) cells and the proteins are termed interferons (see also Chapters 3, 5 and 24). 

Leucocidins kill leucocytes and are produced by many strains of streptococci, most strains of Staphylococcus aureus and likewise most strains of pathogenic Gram-negative bacteria, isolated from sites of infection. 

Konietzko H, Reill G. 1980. The effect of trichloroethylene on some serum enzymes and on the cytoenzymological activity in leucocytes and on the acid base equilibrium. Int Arch Occup Environ Health 47 61-67. 

Intervention trials confirmed this protective role of lycopene on prostate cancer risk. Three primary intervention studies evaluated the effect of lycopene supplementation on prostate cancer risk or on certain risk markers such as prostate-specific antigen (PSA) plasma concentration or oxidative alterations of leucocyte DNA. - All showed increases of plasma and prostate lycopene levels after diet supplementation with lycopene and inverse correlations between tumor incidence and risk biomarkers. 

Alpha-l-antiprotease (ai-AP) limits tissue damage arising from the actions of the leucocyte protease, elastase (Carrell and Travis, 1985), and there is much evidence available for the oxidative inactivation of this protein by oxygen-derived free-radical species and hypochlorous acid/hypochlorite anion (HOCl/OCP). The mechanism of this inactivation appears to involve the oxidation of a critical methionine residue (Met-358) to its corresponding sulphoxide and methionine sulphoxide has been detected in ai-AP samples isolated from the lungs of cigarette smokers (Carp et al., 1982) and rheumatoid synovial fluids (Wong and Travis, 1980). 

Superoxide dismutases (SODs) are a family of cytosolic metalloenzymes that specifically remove (reviewed by Omar etal., 1992). SOD distribution within the body is ubiquitous, being found in erythrocytes as well as most organs and cell types. Three distinct mammalian SOD forms exist CuZnSOD, MnSOD and extracellular SOD (EC-SOD). Their amino-acid sequences differ as well as the transition metals at their active sites. Rheumatoid synovial fluid contains low levels of SOD activity and hence little protection from ROM generated by infiltrating PMNs (Blake etcU., 1981). Furthermore, leucocytes from patients with RA are deficient in MnSOD, which might promote the extracellular leakage of O2 (Pasquier et al., 1984). 

Corkill, M.M., Kirkham, B.W., Haskard, D.O., Barbatis, C., Gibson, T. and Panayi, G.S. (1991). Gold treatment of rheumatoid arthritis decreases synovial expression of the endothelial leucocyte receptor ELAM-1. J. Rheumatol. 18, 1453-1460. 

Kume, N., Cybulsky, M.I. and Gimbrone, M.A. (1992). Lysophosphatidylcholine, a component of atherogenic lipoproteins, mediates mononuclear leucocyte adhesion in cultured human and rabbit endothelial cells. J. Clin. Invest. 90, 1138-1144. 

Pasquier, C., Mach, P.S., Raichuatg, D., Sar ti, G., Amor, B. and Delbarre, F. (1984). Mn-containing SOD deficiency in polymorphonuclear leucocytes of adults with rheumatoid arthritis. Inflammation 8, 27-32. 

Biemond, P., van Eijk, H.G., Swaak, A.J.G. and Koster, J.F. (1984). Iron mobilisation from ferritin by superoxide derived from stimulated polymorphonuclear leucocytes. J. Clin. Invest. 73, 1576-1579. 

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