Ferritin in the serum of normal subjects and patients with iron deficiency and iron overload.
(49/100)
The concentration of ferritin in serum gives a quantitative measure of the amount of storage iron in normal subjects and those with iron deficiency or overload. The mean level in normal men is 69 ng/ml, compared with 35 ng/ml in normal women. A concentration below 10 ng/ml is associated with a low transferrin saturation and iron-deficient erythropoiesis. (+info)
Differential ferrioxamine test in haemochromatosis and liver diseases.
(50/100)
The effect of desferrioxamine is examined in more than 100 patients with liver disease, including haemochromatosis, using the differential ferrioxamine test. The procedure gives a reasonably accurate estimate of the size of the iron stores, as determined by multiple venesection, in patients with idiopathic haemochromatosis. Since desferrioxamine is not specific for storage iron, unequivocally abnormal results are not obtained unless the iron load exceeds about 2.3 g. In other forms of liver disease the effect of desferrioxamine is generally increased compared with that in controls. The results show no correlation with the serum iron level or the degree of hepatic siderosis. High values are usual in the presence of jaundice and overlap the range found in untreated haemochromatosis, adding to other evidence that desferrioxamine can derive iron from a hyperchelatable source unrelated to the stores. It is concluded that in liver diseases other than haemochromatosis the results of the test do not reliably reflect body storage iron content. (+info)
Ferritin metabolism in reticulated-siderocytes.
(51/100)
Reticulated-siderocytes (reticulocytes which contain siderotic granules), obtained from the circulation of pigs after vigorous phlebotomy, were incubated in vitro. A rapid disappearance of granules from the reticulocytes was observed over 24 hr. Simultaneously with the decrease in granules, soluble ferritin accumulated in the media and siderotic granules developed in monocytes. The disappearance of the granules from the reticulated-siderocytes was oxygen-dependent and the loss of granules and the accumulation of ferritin in the media were both prevented by the addition of cyanide or dinitrophenol. It is concluded that the ferritin aggregates in the granules of reticulated-siderocytes are dispersed intracellularly into soluble ferritin, that soluble ferritin is excreted from the cell, and that one or both of these steps is dependent upon oxidative metabolism. Blood monocytes are capable of taking up soluble ferritin from the media and converting this into siderotic granules. Thus, a reticulocyte to plasma to monocyte ferritin pathway has been described. (+info)
Erythropoiesis in the anemia of bone marrow failure.
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The quantitative relationship between red cell volume, erythropoietin level, and erythropoiesis was evaluated in 43 human beings. Results in normal man were compared with studies in patients with anemia from bone marrow failure and with polycythemia vera. The maximum erythropoietin excretion after bleeding normal men was similar to the basal levels found in patients with chronic anemia of similar magnitude. Although erythropoietin values were low in patients with polycythemia vera, bleeding evoked a normal response. In patients anemic from bone marrow failure, basal levels were elevated, and phlebotomy resulted in an increase consistent with the new level of anemia. These observations indicate that erythropoietin level is affected primarily by the degree of anemia and is not influenced by the duration of anemia. In normal subjects, a fivefold increase in urinary erythropoietin was associated with a doubling of erythropoiesis. Despite similar degrees of erythropoietin production, anemic patients with evidence of bone marrow in the lower extremities had greater red cell production. In patients with polycythemia vera, red cell production was inappropriately elevated with regard to the urinary erythropoietin excretion. Bone marrow maturation time was not shortened in patients anemic from bone marrow failure to the same degree as in bled, normal volunteers. In addition to an adequate level of erythropoietin production, normal bone marrow function is necessary for maximal shortening of maturation time. (+info)
Quantitative measurement of iron stores with diethylenetriamine penta-acetic acid.
(53/100)
The use of the chelating agent diethylenetriamine penta-acetic acid (DTPA) for measuring body storage iron was investigated in patients with iron excess whose stores could be determined by venesection. Iron excretion after DTPA bore a close semi-logarithmic relationship to body iron stores when these were increased. The excretion of DTPA-bound (59)Fe was similarly related to the size of the stores, indicating that the increased iron excretion produced by DTPA in iron overload states reflects both increased tissue iron available for chelation and greater stability of the iron-chelate complex. Evidence was obtained that injected (59)Fe-DTPA could be used as a marker for chelated tissue iron enabling the DTPA-chelatable body iron pool to be calculated. There was a highly significant correlation between DTPA-chelatable iron and body storage iron. The regression intercept approximated to the origin, implying a specific relation between the DTPA effect and storage iron. The SE of the mean estimate for storage iron on DTPA-chelatable iron was 0.25 g (5.6%). Mean storage iron values of 392 mg for males and 243 mg for females were predicted from the findings in control subjects. (+info)
The contribution of the adrenal gland to the total amount of progesterone produced in the female rat.
(54/100)
1. The amount of progesterone contained in both adrenal glands of a rat was similar to or larger than the amount of progesterone in the ovaries of the same rat. This was found in unstressed rats, in stressed rats and also in pregnant rats.2. After ether anaesthesia and exsanguination the adrenal progesterone content was increased by 75%; the ovarian progesterone content remained unchanged.3. In contrast, prolonged operative stress resulted in a rise in the ovarian content of progesterone and 20-dihydroprogesterone whereas the adrenal progesterone content of these rats was lower than that of unstressed rats.4. The rate at which progesterone was secreted by the adrenal glands of stressed rats was similar to the ovarian progesterone secretion rate. Rats which were kept under mild stress conditions before the experiment showed higher adrenal progesterone secretion rates. (+info)
Characteristics of marrow production and reticulocyte maturation in normal man in response to anemia.
(55/100)
Erythropoiesis in normal man was studied during periods of phlebotomy-induced anemia of varying severity. This study permitted a comparison of marrow production measurements over a wide range of marrow production levels. As long as the serum iron remained above 50 mug/100 ml, measurements of plasma iron turnover provided an excellent index of marrow production at all levels of red cell production. In contrast, the absolute reticulocyte count demonstrated a poor correlation with the other measurements. This was shown to be the result of a prolongation of the time required for circulating reticulocytes to lose their reticulum, which correlated with the severity of the anemia. For the clinical application of the reticulocyte count as a measurement of marrow production, an adjustment must be made for this alteration in the circulating reticulocyte maturation time. (+info)
Control of marrow production by the level of iron supply.
(56/100)
The level of erythroid marrow production varies widely in different erythropoietic disorders. In part, this reflects the level of erythropoietin stimulation as determined by the severity of the anemia. However, iron supply plays an equally important role in the control of erythropoiesis. As demonstrated in normal individuals subjected to prolonged periods of phlebotomy-induced anemia, the erythroid marrow will increase production by as little as twice to as much as eight times normal, depending on the iron supply available from different iron pools. Whereas the iron delivered from normal reticuloendothelial stores or orally administered iron is sufficient for a marrow production response of only two to three times normal, the increased iron supply from nonviable red cells, hemolysis, or iron dextran infusions permits marrow production to rise acutely to levels of four to eight times normal. (+info)