Granular leukocytes

Hematological Effects. A limited study reported dose-related depressions in white blood cell counts in dogs that were administered single intravenous injections of241 Am at activity levels of 0.1—2.8 pCi/kg (3.7-29.6 kBq/kg) (Dougherty 1970). Maximum depression in granular leukocytes and monocytes was reached approximately 1 month post injection. Depression of lymphocytes occurred more slowly minimal... 

Bone Marrow The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells. [NIH]... 

Neutrophil. A granular leukocyte, having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules. Neutrophils have the properties of chemotaxis adherence to immune complexes, and phagocytosis. 

Granular leukocytes (Granulocytes) Neutrophils Basophils Eosinophils... 

Granular leukocytes are the dominant leukocytes. They are heavily involved with the killing of unwanted intruder cells, and are of many types. 

Acute leukopenia, with almost total absence of granular leukocytes, leukoblastic groups and lymphoid tissue in the bone marrow, was reported in the case of a 36-year-old chemist who had worked with radium for 14 years (Reitter and Martland 1926). 

Immunotoxicity. Studies that assess the potential effects of radium on the immune system of orally or dermally exposed humans have not been located. The case report of a chemist exposed to radium primarily via inhalation for 14 years reported leukopenia and the almost total absence of granular leukocytes, leukoblastic groups, and lymphoid tissue in the bone marrow. No studies on animals exposed via inhalation, oral, or dermal routes have been located. A study reporting a reduction in peripheral white blood cells in intraperitoneally injected rats has been located. The reported observations suggest that immunological effects may be a concern for humans exposed to radium. 

The initial distinction is between granular and agranular leukocytes, depending upon whether they contain small inclusions, called granules, as seen at the level of the light microscope. 

Additional in vitro effects of feverfew include inhibition of histamine release from mast cells and granular components from leukocytes inhibition of smooth muscle contraction cytotoxic effects on human tumor cell lines and antimicrobial effects against gram-positive bacteria, yeasts, and filamentous fungi. 

GMP, granular membrane protein ODFR, oxygen-derived free radicals ELAM, endothelial leukocyte adhesion molecule IL-1, interleukin-1 TNF-alpha, tumor necrosis factor-alpha ICAM, intercellular adhesion molecule IFN-gamma, interferon -gamma VCAM, vascular cell adhesion molecule LFA, lymphocyte-associated antigen CR, complement receptor. 

Secretion. Exocytotic liberation of granular constituents has been demonstrated in leukocytes, platelets and neurological cells. Platelets attacked by alpha-toxin secrete platelet factor 4 and factor 5 (Arvand et a/., 1990 Bhakdi ef al., 1988). Release of the latter leads to assembly of platelet-bound prothrombinase complexes that generate thrombin. Alpha-toxin can thus promote coagulation via its perme-abilizing action on platelets. Release of granule constituents from leukocytes has been observed after permeabilization of these cells by HlyA. For example, large amounts of elastase are secreted into the extracellular medium (Bhakdi eta/., 1989). 

PAF released from IgE-sensitized basophilic leukocytes (and probably other mononuclear cells, such as mast cells) in response to antigen stimulation causes aggregation of platelets and release of their granular constituents (e.g., serotonin). This action of PAF is potent and rivals that of thromboxane A2 (Chapter 18). PAF also is a potent antihypertensive agent when given intravenously to hypertensive rats. It is inactivated by deacetylation by a specific acetylhydrolase. 

Monocyte. Bone marrow-derived mononuclear phagocytic leukocyte, with bean-shaped nucleus and fine granular cytoplasm containing lysosomes, phagocytic vacuoles, and cytoskeletal filaments. Once transported to tissues, monocytes develop into macrophages. 

Figure 5. Histopathology of recovered thrombus. The granular acellular material (platelets) predominated, although a latticework of fibrin trapping leukocytes, red cells, and platelets did occur in discrete areas.

Granulocyte A leukocyte (basophil, mast cell, eosinophil, and neutrophil) with granular cytoplasm and irregularly shaped, lobed nuclei. 

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