Metabolism, iron

In spite of these difficulties, several major observations have already been made. In humans, erythropoietin is found only in the urine of anemic patients. The partially purified hormone is likely to be mucoprotein strangely enough, erythropoietin does not exhibit any species specificity, and the human hormone stimulates erythropoiesis in the monkey and the guinea pig [21-25]. 

Erythropoietin has no direct effect on the intermitot-ic time or on the duration of maturation of the normoblast in vitro. However, bone marrow culture has demonstrated that erythropoietin stimulates the proliferation of the erythropoietic cell. 

The target cell for erythropoietin has not been identified with certainty. When anemia is produced experimentally, pluripotent cells migrate from the bone marrow to the spleen where they become the parent cell for an erythropoietic colony. These pluripotent cells are therefore referred to as colony forming units or CPU. It seems well-established that erythropoietin does not affect migration or the proliferation of CPU. Erythropoietin is more likely to act on an erythropoietic stem cell derived from the pluripotent cell and which is committed to differentiation into an erythrocyte. When the demand for erythropoiesis decreases there seems to be a rise in the CPU cells in the marrow with subsequent increase in myeloid cells [47]. The role of the pluripotent stem cell will be considered in the chapter on inflammation. 

It is not known for certain in which organ erythropoietin is elaborated the kidney has often been suspected of playing this role [26]. The juxtaglomerular apparatus has been claimed as the site of erythropoietin secretion. However, there is no correlation between the disappearance of the vacuole in the cells of the juxtaglomerular apparatus and the appearance of erythropoietin. 

The kidney is certainly not the only source of erythropoietin. Nephrectomized rats subjected to hypoxia have a 10% of normal erythropoietin response indicating that an extrarenal source of erythropoietin exists (most likely the liver). The association of erythrocy-tosis and hepatoma could be explained on the basis of elaboration of erythropoietin by the hepatoma cells. The synthesis of erythropoietin is believed to occur in two steps the formation of an inactive precursor, erythrogenin, which is converted to active erythropoietin by an unidentified plasma factor [48-49]. 

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R. Crichton, Inorganic Biochemistry of Iron Metabolism, Ellis Horwood, Kernel Hempstead, 1991, 212 pp. 

Relatively few heteroaromatic N-oxides occur in nature. The chemistry of compounds that contain the oxidized peptide bond (the so-called hydroxamic acids) and their role in iron metabolism have been reviewed (67SC1443). Another review deals with the natural occurrence of N-oxides (68MI1). 

Cu2+, Cu+ 100 mg 2 mg Iron metabolism, component of enzymes Lobster, cherries, chocolate... 

DOX, as EPI seems to form fewer amounts of ROS and secondary alcohol metabolite, (ii) encapsulation of anthracyclines in uncoated or pegylated liposomes that ensure a good drug delivery to the tumor but not to the heart, (iii) conjugation of anthracyclines with chemical moieties that are selectively recognized by the tumor cells, (iv) coadministration of dexrazoxane, an iron chelator that diminishes the disturbances of iron metabolism and free radical formation in the heart, and (v) administration of anthracyclines by slow infusion rather than 5-10 min bolus (Table 1). Pharmacological interventions with antioxidants have also been considered, but the available clinical studies do not attest to an efficacy of this strategy. 

Problems of iron metabolism with special reference to biochemical, physiological and clinical aspects. W. Keiderling and H. P. Wetzel, Angew. Chem., Int. Ed. Engl., 1966,5, 633-641 (82). 

A New Effect of Aluminum on Iron Metabolism in Mammalian Cells... 

Attention to iron metabolism is particularly important in women for the reason mentioned above. Additionally, in pregnancy, allowances must be made for the growing fetus. Older people with poor dietary habits ( tea and toasters ) may develop iron deficiency. Iron deficiency anemia due to inadequate intake, inadequate utilization, or excessive loss of iron is one of the most prevalent conditions seen in medical practice. 

Table 50-4 summarizes laboratory tests useful in the assessment of patients with abnormalities of iron metabolism. 

Table 50-4. Laboratory tests for assessing patients with disorders of iron metabolism.

Andrews NC Disorders of iron metabolism. N Engl J Med 1999 34l 198fi. 

L. L. Barton, G. V. John.son, K. Schitoskcy, and M. Wertz. Sidcrophore-mediated iron metabolism in growth and nitrogen fixation by alfalfa nodulated with Rhizobium meliloii. J. PhuU Nmr. 79 1201 (1996). 

Decreased red blood cell (RBC) count, hemoglobin (Hgb) and hematocrit (Hct) iron metabolism may also be altered [iron level, total iron binding capacity (TIBC), serum ferritin level, and transferrin saturation (TSAT)]. Erythropoietin levels are not routinely monitored and are generally normal to low. Urine positive for albumin or protein. 

FIGURE 63-2. The distribution of iron use in adults. (From Andrews NC. Disorders of iron metabolism. New Engl j Med 1999 341 (26) 1986-1995. Used by permission from NEJM. Copyright 1999 Massachusetts Medical Society. All rights reserved.)... 

Schoeters G, Van Den Heuvel R, Leppens H, et al. 1990. Distribution of 241Am in offspring from BALB/c mice injected with 241Am and 14 days of gestation Relation to calcium and iron metabolism and comparison with distribution of 241Am after injection of adults. Int J Radiat Biol 58(2) 371-382. 

Do these prokaryotic organisms display a primitive iron metabolism, in the sense that they form a relatively limited number of iron compounds, and are they accordingly good candidates to suspect as direct descendants of the primordial cell ... 

Prelog, V. In Iron Metabolism, p. 73 edited by Gross, A. Berlin-Gdttingen-Heidelberg-New York Springer 1964. 

As mentioned previously, in the AMD retina iron metabolism is compromised (He et al., 2007 Wong et al., 2007). Thus, it is of interest to determine the effects of potential antioxidants in the presence of iron. In an in vitro study of ARPE-19 cells, addition of a lipophilic iron complex led to about a ninefold increase in the photosensitized yield of 7a,(3-cholesterol hydroperoxides (Wrona et al., 2004). In the presence of the iron, ascorbate exerted pro-oxidant effects, while the effects of a-tocopherol, zeaxanthin, or their combination were still protective (Wrona et al., 2004). Thus, it appears that the effects of potential antioxidants are strongly dependent on the sources of oxidative damage. The same antioxidant may be protective under certain conditions and exert deleterious effects when the conditions are changed. Therefore a detailed understanding of the sources of the oxidative damage is required in order to design an adequate antioxidant mixture. 

Inorganic Biochemistry of Iron Metabolism From Molecular Mechanisms to... 

Inorganic biochemistry of iron metabolism from molecular mechanisms to clinical consequences / Robert Crichton with the collaboration of Johan Boelart. .. [et aZ.].—2nd ed. p. cm. 

Iron—Metabolism. 2. Iron proteins. 3. Iron—Metabolism—Disorders. I. Boelart,... 

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