[DIAGNOSIS OF ANEMIA USING RADIOACTIVE ISOTOPES].
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Anemia↗
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Results for “IRON, RADIOACTIVE”
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The effect of acute inflammation on iron metabolism in rats.
Iron metabolism in rats with acute turpentine-induced inflammation was evaluated. In acute inflammation, reduced plasma iron and total iron-binding capacity values, shortened plasma iron disappearance time and lower plasma iron turnover were observed. The administration of 59Fe chondroitin ferrous sulfate in order to evaluate the reticuloendothelial (RE) function revealed a significantly increased 59Fe retention in the liver and lower incorporation into red blood cells. Radioactivity in hepatic RE cells was higher in acute inflammation than in control. These results suggest the possibility of a block in the transfer of iron from RE cells to the plasma iron pool during acute inflammation.
Animals↗
Relationships between iron and vanadium metabolism: the association of vanadium with bovine lactoferrin.
Bovine milk was incubated simultaneously with 48VO2+ and 59Fe3+ ions. The lactoferrin was separated by ion exchange gel chromatography on CM Sephadex C-50 resin. Sephacryl 200 gel filtration of the lactoferrin-containing fractions, from ion exchange chromatography was carried out to dertermine the proportions of 48V and 59Fe radioactivities associated with macromolecules of the size of lactoferrin. It was found that 48V was incorporated into lactoferrin, the milk protein which contains iron. This suggests that lactoferrin may play a role in the bioavailability of vanadium during lactation, as vanadium is an essential element for the growth of some animal species. More generally, the vanadium binding properties of lactoferrin further support previous findings on the possible biochemical role of Fe-containing non hemoproteins in the metabolism of vanadium.
Chromatography, Ion Exchange↗
Accumulation of noradrenaline and its oxidation products by cultured rodent astrocytes.
The accumulation of [3H]noradrenaline ([3H]NA) and its oxidation products was studied in primary cultures of cerebral astrocytes. Astroglial accumulation of radiolabeled catecholamine ([3H] NA and oxidation products) was enhanced by manganese or iron, but it was inhibited by unlabeled NA, dopamine or ascorbate. Tissue: medium ratios of radioactivity increased as extracellular [3H]NA was oxidized. When extracellular oxidation was prevented by ascorbate, as confirmed by high performance liquid chromatography with electrochemical detection, either ouabain pretreatment or nominally Na(+)-free incubation medium inhibited approximately one-half of specific [3H]NA accumulation by rat (but not mouse) astrocytes. These observations suggest that neurological responses to trace metals and ascorbate may arise from the effects of these agents on the clearance of extracellular catecholamines. Astrocytes can accumulate oxidation products of NA more rapidly than they take up NA itself, but ascorbate at physiological concentrations prevents the oxidation process in extracellular fluid. Furthermore, in the presence of ascorbate, Na(+)-dependent transport mediates a significant component of NA accumulation in rat astrocytes.
Animals↗
Renal heme metabolism in hereditary tyrosinemia: use of succinylacetone in rat renal tubules.
Succinylacetone (SA), a metabolic end-product found in urine from individuals with hereditary tyrosinemia and associated renal Fanconi syndrome and a known inhibitor of hepatic 5-aminolevulinic acid dehydratase (ALAD), has been used to study heme metabolism in isolated rat renal tubules. Heme biosynthetic porphyrin precursors are increased selectively in the presence of 4 mmol/1 SA. Total porphyrin content of the tubules are increased approximately 2-fold, while both ferrochelatase and heme oxygenase activities remain unaffected by SA. Nonetheless, total heme content is reduced, as was incorporation of radioactive label from amino[14C]levulinic acid. Cytochrome P-450 content remained unaffected. Impairment of iron uptake and/or transport within the cell or enhancement of heme catabolism via a non-heme oxygenase-dependent pathway could explain the observations.
Amino Acid Metabolism, Inborn Errors↗
Formate bound to cytochrome oxidase can be removed by cyanide and by reduction.
Using 14C-radiolabeled formate we have found that the rapid form of oxidized cytochrome oxidase can bind up to 1 mol of formate. Treatment of this formate-ligated enzyme with excess cyanide releases 97% of the radiolabel while reduction of formate-labeled enzyme with NADH+ruthenium releases 80-85% of the radioactivity. These data are most simply interpreted by assuming that formate binds to the heme iron of cytochrome a3.
Animals↗
Studies on the biosynthesis of cytochrome c.
A soluble cytochrome was isolated and purified from the slime mould Physarum polycephalum and identified as cytochrome c by room-temperature and low-temperature (77 degrees K) difference spectroscopy. A close similarity between P. polycephalum and mammalian cytochromes c was suggested by a comparison of the initial rates of oxidation of both proteins by mammalian mitochondria. This similarity was further emphasized by redox titrations and gel-electrophoretic studies which indicated that P. polycephalum cytochrome c has an oxidation-reduction midpoint potential of +257mV at pH7.0 and a molecular weight of 12500+/-1500 (mean+/-maximum deviation for a set of six measurements). P. polycephalum exhibits an absolute requirement for protohaemin for growth. The (59)Fe-labelled haemin was prepared by chemical synthesis from protoporphyrin. The purified product had a specific radioactivity of 0.8+/-0.02muCi/mol. Growth of P. polycephalum in the presence of [(59)Fe]haemin resulted in the incorporation of (59)Fe into the plasmodial cytochrome c. The specific radioactivity of the cytochrome c haem was 0.36+/-0.02muCi/mol. The high specific radioactivity of the cytochrome haem indicates that synthesis of the holoenzyme must proceed by direct attachment of haem to the apoprotein rather than by the intermediate formation of a protoporphyrinogen-apoprotein complex. The observed decrease in the specific radioactivity of the haem group is attributed to exchange of the (59)Fe with unlabelled iron in the plasmodia either before or during attachment of the haem group to the apoprotein.
Animals↗
Interleukin-1 decreases the level of thymocytes forming rosettes with autologous erythrocytes: a new method of determination of interleukin-1 activity.
It was demonstrated that human, recombinant Il-1 significantly inhibited formation of autologous rosettes by thymocytes. In addition, Il-1 increased the percentage of thymocytes resistant to hydrocortisone. Il-2 was not active in both tests. A new method of determination of Il-1 activity, based on the inhibition of the autologous rosette formation by Il-1 is described. The activity of Il-1 in the supernatant from macrophage cultures, stimulated with carbonyl iron powder, was calculated. The lack of Il-2 interference and no necessity to handle radioactive materials, are the advantages of the new method.
Animals↗
Ferrioxamine B analogues: targeting the FoxA uptake system in the pathogenic Yersinia enterocolitica.
A series of ferrioxamine B analogues that target the bacterium Yersinia enterocolitica were prepared. These iron carriers are composed of three hydroxamate-containing monomeric units. Two identical monomers consist of N-hydroxy-3-aminopropionic acid coupled with beta-alanine, and a third unit at the amino terminal is composed of N-hydroxy-3-aminopropionic acid and one of the following amino acids: beta-alanine (1a), phenylalanine (1b), cyclohexylalanine (1c), or glycine (1d). Thermodynamic results for representatives of the analogues have shown a strong destabilization (3-4 orders of magnitude) of the ferric complexes with respect to ferrioxamine B, probably due to shorter spacers and a more strained structure around the metal center. No significant effect of the variations at the N-terminal has been observed on the stability of the ferric complexes. By contrast, using in vivo radioactive uptake experiments, we have found that these modifications have a substantial effect on the mechanism of iron(III) uptake in the pathogenic bacteria Yersinia enterocolitica. Analogues 1a and 1d were utilized by the ferrioxamine B uptake system (FoxA), while 1b and 1c either used different uptake systems or were transported to the microbial cell nonspecifically by diffusion via the cell membrane. Transport via the FoxA system was also confirmed by uptake experiments with the FoxA deficient strain of Yersinia enterocolitica. A fluorescent marker, attached to 1a in a way that did not interfere with its biological activity, provided additional means to monitor the uptake mechanism by fluorescence techniques. Of particular interest is the observation that 1a was utilized by the uptake system of ferrioxamine B in Yersinia enterocolitica (FoxA) but failed to use the ferrioxamine uptake route in Pseudomonas putida. Here, we present a case in which biomimetic siderophore analogues deliberately designed for a particular bacterium can distinguish between related uptake systems of different microorganisms.
Bacterial Outer Membrane Proteins↗
Assembly of NADH: ubiquinone reductase (complex I) in Neurospora mitochondria. Independent pathways of nuclear-encoded and mitochondrially encoded subunits.
NADH:ubiquinone reductase, the respiratory chain complex I of mitochondria, consists of some 25 nuclear-encoded and seven mitochondrially encoded subunits, and contains as redox groups one FMN, probably one internal ubiquinone and at least four iron-sulphur clusters. We are studying the assembly of the enzyme in Neurospora crassa. The flux of radioactivity in cells that were pulse-labelled with [35S]methionine was followed through immunoprecipitable assembly intermediates into the holoenzyme. Labelled polypeptides were observed to accumulate transiently in a Mr 350,000 intermediate complex. This complex contains all mitochondrially encoded subunits of the enzyme as well as subunits encoded in the nucleus that have no homologous counterparts in a small, merely nuclear-encoded form of the NADH:ubiquinone reductase made by Neurospora crassa cells poisoned with chloramphenicol. With regard to their subunit compositions, the assembly intermediate and small NADH:ubiquinone reductase complement each other almost perfectly to give the subunit composition of the large complex I. These results suggest that two pathways exist in the assembly of complex I that independently lead to the preassembly of two major parts, which subsequently join to form the complex. One preassembled part is related to the small form of NADH:ubiquinone reductase and contributes most of the nuclear-encoded subunits, FMN, three iron-sulphur clusters and the site for the internal ubiquinone. The other part is the assembly intermediate and contributes all mitochondrially encoded subunits, one iron-sulphur cluster and the catalytic site for the substrate ubiquinone. We discuss the results with regard to the evolution of the electron pathway through complex I.
Amino Acid Sequence↗
Developmental changes in transferrin and iron uptake by the brain in the rat.
The uptake of transferrin and iron by the brain, liver and femurs was investigated in rats using 125I-59Fe-transferrin (Tf), and 131I-albumin in order to measure the plasma content of the organs. Measurements in rats ranging in age from birth to 70 days revealed that the rate of iron uptake by the brain increased rapidly over the first 15 days of life, peaking at 15 days and thereafter declining. A similar pattern occurred in the uptake of 125I-Tf. These changes were accompanied by rapid growth of the brain up to 15 days and a decrease in the concentration of non-haem iron. The turnover of 59Fe and 125I-Tf in the brain was also determined by measuring radioactivity in the brain of 15-day rats at various times after injection from 15 min to 13 days. The amount of 59Fe in the brain increased over the first 4 h and thereafter remained constant. By contrast, the 125I-Tf values increased rapidly during the first 15 min to reach a relatively constant level which was maintained for at least 6 h after which it declined. The patterns of uptake by the brain were different from those found in the liver and femurs, indicating that the changes in the brain were specific for that organ.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Quantitative profile scanning for the measurement of organ radioactivity.
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Calcium Isotopes↗
[The use of the human whole-body counter in study of intestinal absorption with the aid of radioactive isotopes].
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Anemia, Pernicious↗
Cellular pool of transient ferric iron, chelatable by deferoxamine and distinct from ferritin, that is involved in oxidative cell injury.
A cellular pool of transient ferric iron that is chelatable by deferoxamine, distinct from ferritin, and required for oxidative cell injury has been identified in cultured rat hepatocytes labeled with 59FeCl3. Pretreatment of hepatocytes with deferoxamine depleted the cellular pool of chelatable iron and protected the cells from an oxidative injury. Incubation of deferoxamine-pretreated hepatocytes in serum-free medium restored both the chelatable iron pool and the susceptibility to oxidative injury. Furthermore, inhibition of protein degradation with chymostatin prevented the restoration of both the chelatable pool and susceptibility to oxidative injury. The deferoxamine-chelatable iron pool was distinguished kinetically and immunochemically from the larger cellular pool of ferritin iron. The labeled iron in the deferoxamine-chelatable pool was transient, unlike either the total cellular uptake of 59Fe or its incorporation into ferritin, both of which increased with time of labeling. With pulse-chase labeling, the percentage of the total uptake of 59Fe that was represented by the deferoxamine-chelatable pool decreased. At the same time, the percentage represented by radioactivity immunoprecipitable as ferritin increased. Furthermore, immunoprecipitation of ferritin from the labeled lysates enriched the resulting immunosupernatants in deferoxamine-chelatable iron. The degree of enrichment for chelatable iron correlated with the percentage of the cellular label that was immunoprecipitable as ferritin. The deferoxamine-chelatable iron appears to represent a metabolically common pool of iron that is rapidly in transit through the cell. Extracellular iron entering the pool can be utilized for heme synthesis or stored in ferritin, whereas protein degradation releases storage iron into this pool.
Animals↗
[Level and pattern of morbidity of children residing in the Ukrainian S.S.R. exposed to radioactive pollution as the result of the Chernobyl AES accident].
It has been shown that there is a significant increase in total morbidity in children residing in the areas exposed to radioactive pollution due to the accident at the Chernobyl Atomic Power Station. This is due largely to higher morbidity of respiratory disease. There is also an increased in the incidence of digestive diseases, iron-deficiency anemias, mental disorders. The recorded growth of childhood morbidity in the areas examined is much higher than that in the children living in other areas unexposed to radioactive pollution.
Accidents↗
Survey of radioactive agents for in vitro labeling of phagocytic leukocytes. II. Particles.
When various radioactive particles are incubated and tumbled in concentrated suspensions of blood phagocytes at body temperature for 1 hr, they bind to the phagocytic cells with a labeling yield of 30-40%. In vitro experiments show that, for some radioactive colloids, a sizeable fraction of the total cellular binding results from nonspecific surface adsorption to other cells and from reversible surface adsorption to phagocytes without engulfment. No completely satisfactory in vitro methods have been found for separating leukocytes with completely engulfed particles from those with surface-adherent particles; nonetheless, surface adherence can be partially reversed by 20% acid citrate dextrose (ACD) solution or by an excess of nonradioactive colloid. Gelatinization of colloidal particles tends to increase their binding to phagocytic cells but also increases the degree of nonspecific adherence to other cells. Technetium-99m-millimicrospheres, 0.5-2 mum in diameter, are optimal in size for phagocytosis by neutrophils, and their non-specific adherence to other cells is minimal. Because of the microspheres' poor stability in aqueous suspension, however, it is technically difficult to separate free from phagocytosed radioactivity after cell incubation. The highly stable small-particle colloids (less than 0.1 mum), such as 198Au-colloid or 111In-colloid without iron carrier, are phagocytosed poorly or not at all by neutrophils, although they are engulfed by mononuclear cells.
Chlorides↗
[Metallic trace elements--A1, Cd, Cu, Fe--in solutions of 111InCl3: determination by flameless atomic absorption and results in 111In-radiolabeling of monoclonal antibodies].
Determination of trace elements in 111InCl3 solution have been carried out by flameless atomic absorption spectrometry. Five successive batches from three European companies have been analysed. The means of measured values range from 4560 to 6930 micrograms L-1 for aluminium, 131 to 874 for cadmium, 49 to 300 for copper, 387 to 698 for iron. Using two molar ration indexes, trivalent metallic traces have been compared to theoretical 111In content. The trace elements largely exceed radioactive material. As Fe and In have similar chemical properties, it results in low specific activity of radioactive complex when labeling monoclonal antibodies by 111In. Using a mathematical model, a detrimental effect of Fe trace levels has been studied.
Aluminum↗
Increased ferritin synthesis and iron uptake in inflammatory mouse macrophages.
Iron metabolism during inflammation was studied in normal and stimulated peritoneal mouse macrophages. A model was developed for detection of ferritin synthesis in these cells, and inflammatory stimulation was produced by i.p. injection of thioglycollate broth or i.m. injection of turpentine. The cells were adhered to culture discs and incubated at 37 degrees C with 59Fe-transferrin and 3H-leucine, and after washing the cell lysate was chromatographed. In the lysate from stimulated macrophages iron and tritium activity was found in a joint peak, and both were precipitated by a specific anti-mouse ferritin antibody. No significant peaks of radioactivity were found in lysates from normal cells. This showed that inflammatory RES cells have an increased ferritin synthesis. The uptake of 59Fe was investigated in a separate study and the stimulated macrophages were found to have a much higher iron uptake than normal macrophages.
Animals↗