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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Young mycelia of the fungus Neurospora crassa contain a soluble NADH-linked sideramine reductase, which may be responsible for liberating iron in vivo from accumulated sideramines during iron-deficient cultivation. The enzymes can be assayed using a soluble supernatant fraction, EDTA, and an atmosphere of pure nitrogen. The enzyme is stable without loss of activity up to 45 degrees C and has an optimum of activity at pH 7.0. Besides coprogen (Km = 100 micrometer, V=2.8 nmol/min per mg protein), some other ferrichrome-type compounds are reduced. However, ferrichrome, ferrirubin coprogen B and ferrioxamine are poor substrates. When the mucelia were grown in a medium containing 10(-5) M ferri iron, the activity of the reductase was found to be only 30% of that found under low iron conditions. The enzyme is inhibited by oxygen, SH-alkylating agents and partly by some detergents. Unlike the reductase of N. crassa, the corresponding enzyme from Aspergillus fumigatus revealed low reduction of coprogen and high reduction of ferrichrome, indicating genusdependent specificities of sideramine reduction enzymes in fungi. The participation of acids of the citric acid cycle as natural iron acceptors during strong iron deficiency is studied and confirmed by iron uptake measurements on isolated mitochondria.
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PMID:Enzymatic release of iron from sideramines in fungi. NADH:sideramine oxidoreductase in Neurospora crassa. 14 35

A high correlation coefficient r = -0.832 (P r +/- 0 less than 0.0001) was estimated in man for the inverse relationship between the diagnostic 59Fe2+-absorption and the serum ferritin concentration which is very close to the correlation r = -0.88 as described for the relationship between the diagnostic 59Fe2+-absorption and the diffuse cytoplasmic storage iron in the bone marrow macrophages. The increase of the diagnostic 59Fe2+-absorption seems to be an earlier and more sensitive indicator of depleted iron stores whereas the serum ferritin decreases somewhat later during the development of iron deficiency.
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PMID:Correlation between diagnostic 59Fe2+-absorption and serum ferritin concentration in man. 14 49

In juvenile patients with a severe and longstanding iron deficiency disease several abnormal features such as delayed growth, retarded development and maturation are displayed. The roentgenological examination of the sella turcica in 81 patients and the determination of the sellar size in 73 cases, including 40 men and 33 women, by employing the method of Haas with a slight modification and the following comparison of the results with the values obtained by this author in normal individuals of the same sex and age revealed that in the iron deficient patients the sellar area is considerably reduced. In addition, it could be shown that in the patients the normal augmentation of the size with the advancing age is likewise diminished and comes to an early standstill. It could be, moreover, demonstrated that in men the sellar size and growth are more reduced than in women and that the difference in the patients is much larger than the difference existing normally between both sexes. The reduced size of the sella turcica in the patients indicated that the pituitary gland placed in the sellar cavity is likewise diminished and that the activity of the gland, as far as the function is related to the volume, is equally decreased. This assumption is in good keeping with the clinical findings in the patients being attributed to a low and failing hormonal activity. The close relation between volume and function of the pituitary gland, is proved by the observation made in the patients after the administration of iron showing that the size of the sella is considerably augmented during a relatively short space of time and that at the same time a definite amelioration of clinical symptoms occurs. Thus the X-ray examination of the sella turcica and the determination of its area is a suitable method for a comparative investigation of the size and function of the pituitary gland. It offers a valuable tool for studying the disorders of growth, development and maturation in juvenile patients with a severe and longstanding iron deficiency disease and for investigating the relation of these clinical features to the pituitary function.
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PMID:[Behaviour of the sella turcica in juveniles with severe iron deficiency (author's transl)]. 15 70

Cytochrome-deficient cells of a strain of Escherichia coli lacking 5-amino-levulinate synthetase have been used to study proton translocation associated with the reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase region of the electron transport chain. Menadione was used as electron acceptor, and mannitol was used as the substrate for the generation of intracellular NADH. The effects of iron deficiency on NADH- and D-lactate-menadione reductase activities were studied in iron-deficient cells of a mutant strain unable to synthesize the iron chelator enterochelin; both activities were reduced. The NADH- menadione reductase activity in cytochrome-deficient cells was associated with proton translocation and could be coupled to the uptake of proline. However proton translocation associated with the NADH-menadione reductase activity was prevented by a mutation in an unc gene. It was concluded that there is no proton translocation associated with the NADH-dehydrogenase region of the electron transport chain in E. coli and that the proton translocation obtained with mannitol as substrate is due to the activity of membrane-bound adenosine triphosphatase.
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PMID:Proton translocation in cytochrome-deficient mutants of Escherichia coli. 15 8

The prevention of iron deficiency requires attention to the toal feeding regimen as well as to its iron content. The use of fresh cow's milk in early infancy, a common practice, is associated with the development of measurable degrees of iron deficiency. In many instances excessive amounts of milk produce severe iron deficiency anemia during the second year of life in infants of greater than average birth weight. The psychological factors leading to such milk intakes have been reviewed. Present evidence supports the hypothesis that occult blood loss is a major etiologic factor in iron deficiency in infancy. Although the mechaisms of intestinal damage by fresh cow's milk protein is highly suspect and that the concentration of protein in the formula may play a significant role. What about iron fortification of infant formulas? Itis becoming clear that fullterm infants fed prepared formulas having protein concentrations approaching that of human milk and fed diets containing about 7 mg of iron daily after the age of 3 months infrequently develop biochemical iron deficiency. The addition of iron to the formula at levels of 10 to 12 mg/gt is assurance that their intake is adequate, whatever the iron intake from other foods. Low-birth-weight infants have increased iron needs because of their rapid growth. Iron-ofrtified formulas are necessary for these infants. Since iron from fortified formulas is well absorbed during the first three months of life, even if it is not immediately used for hemoglobin formation, an inccrease in the iron stores will occur...
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PMID:The prevention of iron dificency anemia in infants. 16 77

The effect of iron deficiency on a number or iron containing enzymes in rat liver has been examined. In addition, 6-phosphogluconate dehydrogenase and glucose 6-phosphate dehydrogenase have been assayed. Of the mitochondrial electron transport reactions only succinate-cytochrome C reductase activity was decreased in iron deficient animals. Microsomal reductase enzymes associated with the NADPH-oxidase system were also markedly decreased although cytochrome P450 concentrations were unaffected. Both 6-phosphogluconate dehydrogenase and glucose 6-phosphate dehydrogenase were reduced in young iron deficient rats but the former had returned to control levels at the age of 14 weeks.
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PMID:The effects of iron deficiency on rat liver enzymes. 17 99

Using electron microscopy radioautography, the deposition of intravenously administered iron in the duodenal epithelium was studied in normal mice, iron-overloaded and iron-deficient mice, and in mice with X-linked anemia (gene symbol sla) 4 and 24 hours after injection of 59Fe. The resolution of radioautography with 59Fe was determined with a line source and the distance from the hot line within which half of the grains fell (HD value) was 1650 A. In normal, iron-overloaded, and sla mice, radioiron was localized in the undifferentiated crypt cells at 4 hours and in the absorptive cells of the luminal half of the villi, at 24 hours. At both times, the vast majority of the grains was seen over the areas rich in free ribosomes and rough endoplasmic reticulum. In iron-deficient mice, grains were not found at either time. The amount of iron incorporated in the crypt cells was related to the size of the body iron stores. It is postulated that the amount of iron incorporated in the crypt cells is the result of interaction between uptake and return to the blood of the circulating iron. Once the crypt cells have differentiated into absorptive cells, the uptake and recirculation of iron from and to the blood would cease, leaving an amount of "message" iron which determines the absorptive cell's subsequent capacity for iron transfer to the plasma. In sla mice, in spite of tissue iron deficiency, the amount of iron deposited was similar to that of normal mice and markedly increased after treatment of the anemia. The accumulation of iron in the crypt cells may result from the decreased return to the blood of the incorporated circulating iron, due to the postulated deficient iron carrier mechanism in sla, or may be a consequence of increased avidity of the absorptive cells for circulating iron. In either event, the result would be that the absorptive cell receives an inappropriate message with resulting inappropriate absorption of iron.
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PMID:Uptake of circulating iron by the duodenum of normal mice and mice with altered iron stores, including sex-linked anemia: high resolution radioautographic study. 18 Mar 29

We have examined the effects of total body iron deficiency on the function of mitochondria isolated from rat hearts. Male Wistar rats were weaned at 21 days and divided into an experimental iron-deficient group and a control group. Both groups received identical diet but an iron supplement (180 mg of ferrous sulfate per kg of diet) was added for the control group. Rats were studied at 7 and 14 weeks. Iron-deficient rats weighed less than controls but showed significantly increased ventricle to body weight ratio at both 7 and 14 weeks, indicating relative cardiac hypertrophy. Isolated mitochondrial fractions from iron-deficient and control rats contained similar proportions of whole homogenate protein and succinic cytochrome c reductase activity, indicating that the fractions isolated from the experimental and control rats were comparable. In iron-deficient rats NADH cytochrome c reductase, succinic cytochrome c reductase, succinic dehydrogenase, and NADH ferricyanide oxidoreductase activities were all significantly reduced at 7 and 14 weeks. Cytochrome c oxidase activity was significantly reduced only at 14 weeks as were the concentrations of cytochromes a3, c1, and b. The rate of oxygen uptake by mitochondria was significantly lower at both 7 and 14 weeks but the P/O ratio was unaltered. We conclude that iron deficiency is associated with impairment of myocardial mitochondrial electron transport.
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PMID:The effects of iron deficiency on the respiratory function and cytochrome content of rat heart mitochondria. 18 77

Rats of Wistar strain, of same age, were kept on iron free diet up to nearly absolute iron deficiency in iron depots. Afterwards granuloma was produced by implantation of cotton pellets subcutaneously. For characterization of the collagen biosynthesis in the granuloma the neutral salt soluble collagen and the activity of the prolyl hydroxylase were measured in the granuloma 4, 8 and 12 days after cotton pellet implantation. At the same time "collagen-like" protein was determined in the serum of the animals. The enzyme activity was statistically significant lower in the granuloma of animals on iron deficiency than in the granuloma of the comparable groups on normal diet. Statistically significant higher concentration of neutral salt soluble collagen was found 8 and 12 days after cotton pellet implantation in the group on iron free diet. There was no significant difference as to the serum levels of "collagen-like" protein in serum.
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PMID:[Parameters of collagen biosynthesis in cotton pellet granuloma of rats on iron deficiency (author's transl)]. 21 Apr 87

Iron deficiency causes cytological and enzymic changes in the gastrointestinal mucosa of animals and man that can be expected to impair the digestion and absorption of other nutrients. In experiment 1, healthy, weanling, female rats were grouped into pair-mates and pair-fed either an iron-deficient or an iron-supplemented diet for 19 weeks. In experiment 2, iron-deficient offspring reared by iron-deficient females were grouped into pair-mates and pair-fed either an iron-deficient or an iron-supplemented diet for 15 weeks. In experiment 1, apparent absorption of calcium was significantly depressed in week 9 (p less than 0.001) and slightly depressed in weeks 10 and 11. In experiment 2, the apparent absorption of calcium was significantly (p less than 0.001) depressed in weeks 6, 13, and 14. Absorption was not measured in other weeks in these experiments. The concentrations of calcium and magnesium were consistently higher in the fecal dry matter of the iron deficient rats in both experiments. It was concluded that any defects in digestion and absorption by the iron-deficient rats was confined primarily to the mineral nutrients because in both experiments apparent absorption of dry matter was consistently higher in these animals compared to their iron-supplemented pair-mates.
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PMID:Utilization of dietary calcium by iron-deficient rats. 24 Oct 35


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