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

Enlarged spleen, fever, increased susceptibility to infections, and thrombocytosis, are manifestations of iron deficiency which are relatively specific of pediatric patients. Iron deficiency anemia is part of everyday pediatrics. Patients are referred to the hematologist in the following situations: 1) Therapy is ineffective for one of the following reasons: the hypochromic anemia is not caused by iron deficiency (hemoglobinopathies); iron is less efficiently used because of transferrin deficiency or infectious, inflammatory or cancerous disease; iron therapy is inadequate either because of insufficient dosage or of suboptimal duration. 2) A relapse occurs in spite of adequate therapy. Before investigating the digestive tract, abnormal hemostasis. Osler-Weber-Rendu syndrome and pulmonary hemosiderosis should be considered. 3) Iron deficiency anemia is less common in adolescents. This condition, known as chlorosis, results mainly from increased needs, unbalanced diet, and onset of menses. In some cases no explanation is found but iron therapy leads to recovery. 4) Difficult problems arise in patients with complex anemias: iron deficiency with folic acid or vitamin B12 deficiency; hyposideremia complicating one of the hemoglobinopathies.
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PMID:[Iron-deficiency anemia. Hematologist's viewpoint]. 629 49

The literature of the nineteenth century often referred to chlorosis. Some examples, taken from French sources, are mentioned. The illness was only given its name at the beginning of the seventeenth century, but the clinical picture of febris alba virginum had been known for a long time previously. The history of chlorosis is interesting because of the variety of explanations, including the psychological, it attracted before it came to be recognized as due to hypochromic anaemia or iron deficiency.
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PMID:Chlorosis -the "green sickness". 702 33

Chlorosis was the first described by Lange in the 16th century as an anemia often found in adolescent girls and young women. Despite the recommendation by Sydenham in the 17th century that the condition be treated with iron supplements, chlorosis was classified among the hysterical diseases. By the end of the 19th century, the incidence of chlorosis apparently increased. It became an important subject of medical literature, but the true nature of the disease remained unknown. Many physicians believed that it was a result of a nervous disorder affecting various organ systems including the blood-forming organs. Iron medication became popular because of its therapeutic value, but its mode of action was controversial. Stockman in 1895 proposed that chlorosis was the result of a nutritional iron deficiency, but his view was largely ignored for decades. After World War I the incidence of chlorosis declined, and the disease ceased to be reported in the 1930s.
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PMID:Chlorosis: the rise and disappearance of a nutritional disease. 761 96

Arabidopsis thaliana (L.) Heynh. Columbia wild type and a root hair-less mutant RM57 were grown on iron-containing and iron-deficient nutrient solutions. In both genotypes, ferric chelate reductase (FCR) of intact roots was induced upon iron deficiency and followed a Michaelis-Menten kinetic with a Km of 45 and 54 microM FeIII-EDTA and a Vmax of 42 and 33 nmol Fe2+.(g FW)-1.min-1 for the wild type and the mutant, respectively. The pH optimum for the reaction was around pH 5.5. The approximately four fold stimulation of FCR activity was independent of formation of root hairs and/or transfer cells induced by iron deficiency. Iron-deficiency-induced chlorosis and the development of a rigid root habit disappeared when ferric chelate was applied to the leaves, while FCR activity remained unchanged. The time course of the responses to iron deficiency showed that morphological and physiological responses were controlled separately.
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PMID:Responses to iron deficiency in Arabidopsis thaliana: the Turbo iron reductase does not depend on the formation of root hairs and transfer cells. 776 49

Experiments have been carried out with field-grown pear trees to investigate the effect of iron chlorosis on the composition of the leaf apoplast. Iron deficiency was associated with an increase in the leaf apoplastic pH from the control values of 5.5-5.9 to 6.5-6.6, as judged from direct pH measurements in apoplastic fluid obtained by centrifugation and fluorescence of leaves incubated with 5-CF. The major organic acids found in leaf apoplastic fluid of iron-deficient and iron-sufficient pear leaves were malate, citrate and ascorbate. The total concentration of organic acids was 2.9 mM in the controls and increased to 5.5 mM in Fe-deficient leaves. The total apoplastic concentration of inorganic cations (Ca, K and Mg) increased with Fe deficiency from 15 to 20 mM. The total apoplastic concentration of inorganic anions (Cl-, NO3-, SO4(2-) and HPO4(2-)) did not change with Fe deficiency. Iron concentrations decreased from 4 to 1.6 microM with Fe deficiency. The major Fe species predicted to exist in the apoplast was [FeCitOH](-1) in both Fe-sufficient and deficient leaves. Organic acids in whole leaf homogenates increased from 20 to 40 nmol x m(-2) with Fe deficiency. The accumulation of organic anions in the Fe-deficient leaves does not appear to be associated to an increased C fixation in leaves, but rather it seems to be a consequence of C transport via xylem.
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PMID:Iron deficiency-associated changes in the composition of the leaf apoplastic fluid from field-grown pear (Pyrus communis L.) trees. 1145 9

The mutants irt1-1 and irt1-2 of Arabidopsis thaliana were identified among a collection of T-DNA-tagged lines on the basis of a decrease in the effective quantum yield of photosystem II. The mutations responsible interfere with expression of IRT1, a nuclear gene that encodes the metal ion transporter IRT1. In irt1 mutants, photosensitivity and chlorophyll fluorescence parameters, as well as abundance and composition of the photosynthetic apparatus, are significantly altered. Additional effects of the mutation under greenhouse conditions, including chlorosis and a drastic reduction in growth rate and fertility, are compatible with a deficiency in iron transport. Propagation of irt1 plants on media supplemented with additional quantities of iron salts restores almost all aspects of wild-type behaviour. The irt2-1 mutant, which carries an En insertion in the highly homologous IRT2 gene of Arabidopsis thaliana, was identified by reverse genetics and shows no symptoms of iron deficiency. This, together with the finding that irt1-1 can be complemented by 35S::IRT1 but not by 35S::IRT2, demonstrates that, although the products of the two genes are closely related, only AtIRT1 is required for iron homeostasis under physiological conditions.
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PMID:The metal ion transporter IRT1 is necessary for iron homeostasis and efficient photosynthesis in Arabidopsis thaliana. 1220 49

IRT1 and IRT2 are members of the Arabidopsis ZIP metal transporter family that are specifically induced by iron deprivation in roots and act as heterologous suppressors of yeast mutations inhibiting iron and zinc uptake. Although IRT1 and IRT2 are thought to perform redundant functions as root-specific metal transporters, insertional inactivation of the IRT1 gene alone results in typical symptoms of iron deficiency causing severe leaf chlorosis and lethality in soil. The irt1 mutation is characterized by specific developmental defects, including a drastic reduction of chloroplast thylakoid stacking into grana and lack of palisade parenchyma differentiation in leaves, reduced number of vascular bundles in stems, and irregular patterns of enlarged endodermal and cortex cells in roots. Pulse labeling with 59Fe through the root system shows that the irt1 mutation reduces iron accumulation in the shoots. Short-term labeling with 65Zn reveals no alteration in spatial distribution of zinc, but indicates a lower level of zinc accumulation. In comparison to wild-type, the irt1 mutant responds to iron and zinc deprivation by altered expression of certain zinc and iron transporter genes, which results in the activation of ZIP1 in shoots, reduction of ZIP2 transcript levels in roots, and enhanced expression of IRT2 in roots. These data support the conclusion that IRT1 is an essential metal transporter required for proper development and regulation of iron and zinc homeostasis in Arabidopsis.
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PMID:Knock-out of Arabidopsis metal transporter gene IRT1 results in iron deficiency accompanied by cell differentiation defects. 1237 93

Iron deficiency impairs chlorophyll biosynthesis and chloroplast development. In leaves, most of the iron must cross several biological membranes to reach the chloroplast. The components involved in the complex internal iron transport are largely unknown. Nitric oxide (NO), a bioactive free radical, can react with transition metals to form metal-nitrosyl complexes. Sodium nitroprusside, an NO donor, completely prevented leaf interveinal chlorosis in maize (Zea mays) plants growing with an iron concentration as low as 10 microM Fe-EDTA in the nutrient solution. S-Nitroso-N-acetylpenicillamine, another NO donor, as well as gaseous NO supply in a translucent chamber were also able to revert the iron deficiency symptoms. A specific NO scavenger, 2-(4-carboxy-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, blocked the effect of the NO donors. The effect of NO treatment on the photosynthetic apparatus of iron-deficient plants was also studied. Electron micrographs of mesophyll cells from iron-deficient maize plants revealed plastids with few photosynthetic lamellae and rudimentary grana. In contrast, in NO-treated maize plants, mesophyll chloroplast appeared completely developed. NO treatment did not increase iron content in plant organs, when expressed in a fresh matter basis, suggesting that root iron uptake was not enhanced. NO scavengers 2-(4-carboxy-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and methylene blue promoted interveinal chlorosis in iron-replete maize plants (growing in 250 microM Fe-EDTA). Even though results support a role for endogenous NO in iron nutrition, experiments did not establish an essential role. NO was also able to revert the chlorotic phenotype of the iron-inefficient maize mutants yellow stripe1 and yellow stripe3, both impaired in the iron uptake mechanisms. All together, these results support a biological action of NO on the availability and/or delivery of metabolically active iron within the plant.
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PMID:Nitric oxide improves internal iron availability in plants. 1248 Oct 68

Chlorosis or 'green sickness' was frequently seen in languid girls and young women in the 19th century but disappeared completely in the first part of the 20th century. The clinical picture comprised menstrual disorders such as ameonrrhoea, pallor and many vague symptoms including apathy and hypochondria. At a later stage anaemia and iron deficiency became prominent characteristics. The skin was reported to take on a greenish hue, but this is disputable. Related diseases were hysteria and anorexia. In the middle of the 19th century hydrotherapy was treatment of choice, and later on iron therapy came to the fore. In 1898 Catharine van Tussenbroek, the first female Dutch gynaecologist, pointed to the social factors at the root of the disease: the lack of perspective for young girls in society at that time. The disappearance of the disease can be partially attributed to improved diagnostics but more so to changes in the social position of women around the turn of the century.
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PMID:[Chlorosis, the lost disease of languid young women]. 1473 54

A combined effect of iron deficiency and root hypoxia on the biochemical composition activity and structure of chloroplasts in pea leaves have been studied. Both factors are shown to affect the accumulation of chlorophyll causing leaf chlorosis. At iron deficiency chlorosis occurs from the top of plant leaves. At root hypoxia chlorosis starts from the lower strata. At a combined action of both factors the destructive effects are summarized. It was established that light-harvesting complexes of photosystems were reduced stronger at iron deficiency, while complexes of reaction centers of photosystem I and photosystem II are lessened at root hypoxia. Nevertheless, even at a combined effect of both factors yellow leaves preserved small amounts of any pigment-protein complexes and their functional activities. The ultrastructure of chloroplasts during leaf chlorosis was gradually reduced. At first, intergranal sites of thylakoids and then granal ones were destroyed, that was typical of iron deficiency. However, even yellow and almost white leaves kept small thylakoids, capable of forming stacking and small grana made of 2-3 thylakoids. It has been concluded that the destructive effects are summarized due to different kinds of action of iron deficiency and root hypoxia on the structure and functioning of leaves at their combined action.
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PMID:[Structural and functional organization of chloroplasts in leaves of Pisum sativum L. under conditions of root hypoxia and iron deficiency]. 1521 30


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