Leukocyte acids

The most clearly documented role lor selenium is as a necessary component of glutathione peroxidase. Selenium is also involved in the functions of additional enzymes, e.g.. type I iodoihvronine deiodinase. leukocyte acid phosphatase, and glucuronidases. A role for selenium in electron transfer has been suggested as has involvement in nonheme iron proteins. Selenium and vitamin b appear to be necessary lor proper functioning of lysosomal membranes. A role for selenium in metabolism of thyroid hormone has been continued. 

The acid phosphatase activity of leukocytes was studied by Valentine and Beck (B8, VI) in 1951. There appear, however, to have been no significant attempts to purify the enzyme from this source, or to describe its characteristics. Recently, Szajd and Pajdak (S32) indicated the isoenzyme characteristics of leukocyte acid phosphatase, and Li and his associates (L7, L8) studied this problem in greater detail. They suspended a leukocyte preparation, carefully separated from blood, in 5% Triton X-100 to yield a final concentration of 10 X 10 cells per milliliter and subjected the suspension to six cycles of alternate freeze-thaw treatment. The suspension was then centrifuged at lOOOp for 15 minutes at 4°C, and the supernatant was used for electrophoretic studies. Specimens centrifuged at 100,000p for 15 minutes gave the same results. Electrophoresis was carried out at 4°C for 60 minutes on a 7.5% acrylamide gel matrix containing 0.5% Triton X-100 at pH 4.0 with a current of 4 mA per tube. The substrate was -naphthyl phosphate. 

The values for the normal leukocyte acid phosphatase activity and the normal isoenzyme pattern will be described in connection with the alteration of these in various hematologic and hematopoietic disorders. 

Leukocytic Acid Phosphatase Activity in Hematologic AND Hematopoietic Disease... 

Leukocyte Acid Phosphatase Activity in Various Hematologic Diseases ... 

DeChatelet LR, McCall CE, Cooper MR, Shirley PS. Inhibition of leukocyte acid phosphatase by heparin. Chn Chem 1972 18(12) 1532-4. 

Glucocorticoids inhibit the release of leukocytic acid hydrolases, and also inhibit the adhesion of leukocytes to the vascular endothelium. 

Absorption, Transport, and Excretion. The vitamin is absorbed through the mouth, the stomach, and predominantly through the distal portion of the small intestine, and hence, penetrates into the bloodstream. Ascorbic acid is widely distributed to the cells of the body and is mainly present in the white blood cells (leukocytes). The ascorbic acid concentration in these cells is about 150 times its concentration in the plasma (150,151). Dehydroascorbic acid is the main form in the red blood cells (erythrocytes). White blood cells are involved in the destmction of bacteria. 

The adrenal glands and pituitary glands have the highest tissue concentration of ascorbic acid. The brain, Hver, and spleen, however, represent the largest contribution to the body pool. Plasma and leukocyte ascorbic acid levels decrease with increasing age (152). Elderly people require higher ascorbic acid intakes than children to reach the same plasma and tissue concentration (153). 

Interferon (IFN) differs from bona fide antiviral diugs since it is a natural defense protein of the host organism and does not directly interfere with the viral replication steps. Interferons are small glycoproteins inducing immune modulatory and antiviral activities. They are secreted by lymphocytes, leukocytes and fibroblasts in response to foreign nucleic acids (dsRNA). 

The antiinflammatory effects of statins likely result from their ability to inhibit the formation of mevalonic acid. Downstream products of this molecule include not only the end product, cholesterol, but also several isoprenoid intermediates that covalently modify ( pre-nylate ) certain key intracellular signaling molecules. Statin treatment reduces leukocyte adhesion, accumulation of macrophages, MMPs, tissue factor, and other proinflammatory mediators. By acting on the MHC class II transactivator (CIITA), statins also interfere with antigen presentation and subsequent T-cell activation. Statin treatment can also limit platelet activation in some assays as well. All these results support the concept that in addition to their favorable effect on the lipid profile, statins can also exert an array of antiinflammatory and immunomodulatory actions. 

The leukotrienes are a family of conjugated trienes formed from eicosanoic acids in leukocytes, mastocytoma cells, platelets, and macrophages by the lipoxyge-... 

Evans, J.F., Leblanc, Y., Fitzsimmons, B.J., Charleson, S.M., Nathaniel, D. and Leveille, C. (1987). Activation ofleuko-cy te movement and displacement of [ H]-leukotriene B4 from leukocyte membrane preparations by (12 - and (12S)-hydroxyeicosate-traenoic acid. Biochem. Biophys. Acta 917, 406-410. 

Irreversible inhibition is probably due to the alkylation of a histidine residue.43 Chymotrypsin is selectively inactivated with no or poor inhibition of human leukocyte elastase (HLE) with a major difference the inactivation of HLE is transient.42,43 The calculated intrinsic reactivity of the coumarin derivatives, using a model of a nucleophilic reaction between the ligand and the methanol-water pair, indicates that the inhibitor potency cannot be explained solely by differences in the reactivity of the lactonic carbonyl group toward the nucleophilic attack 43 Studies on pyridyl esters of 6-(chloromethyl)-2-oxo-2//-1 -benzopyran-3-carboxylic acid (5 and 6, Fig. 11.5) and related structures having various substituents at the 6-position (7, Fig. 11.5) revealed that compounds 5 and 6 are powerful inhibitors of human leukocyte elastase and a-chymotrypsin thrombin is inhibited in some cases whereas trypsin is not inhibited.21... 

Doucet, C. Pochet, L. Thierry, N. Pirotte, B. Delarge, J. Reboud-Ravaux, M. 6-Substituted 2-OXO-2H-1 -benzopyran-3-carboxyI ic acid as a core structure for specific inhibitors of human leukocyte elastase. J. Med. Chem. 1999, 42, 4161—4171. 

---