Percentage Of Iron Research Articles

Some magnetic properties of the cores of various ferritins

57Fe Mossbauer spectra of the mineral cores of various ferritins show both paramagnetic and superparamagnetic relaxation effects and in some cases a combination of both. Correlations have been observed between data on the crystallinity, phosphate content and percentage iron in the cores and their magnetic ordering and mean blocking temperatures derived from the Mossbauer spectra.

X-ray Absorption Spectroscopic Investigation of Sulfur Sites in Coal: Organic Sulfur Identification

High-resolution x-ray absorption spectroscopy was used to probe the chemical and structural environments of sulfur in coal. Measurement of the sulfur Kedge spectra down to 2472.0 electron volts under nonvacuum conditions was made possible in an all-helium path, and a Stern-Heald type ion chamber was used for fluorescence detection. For a number of selected sulfur-containing minerals and organic model compounds, results show that near-edge spectral features are diagnostic for sulfur in specific organic moieties such as thiols, disulfides, and various heterocyclics, as well as in mineral sulfide and sulfate phases. The spectrum of a model system containing 35 percent iron pyrite and 65 percent benzothiophene was found to match the observed spectral features of a bituminous coal from the eastern United States.

The intake and excretion of lead and cadmium by the elderly

Metabolic balance studies for lead and cadmium were carried out in 23 healthy elderly people aged 69.7 to 85.5 yr while living in their own homes and eating self-selected diets. Mean intakes of lead and cadmium were 54.6 and 8.6 µg/day, with mean retentions of −8.7 and −1.7 µg/day, respectively. Daily dietary lead correlated (p < 0.05) with the intake of energy, nitrogen, calcium, iron, and zinc but not with manganese or copper. Dietary intake of cadmium correlated (p < 0.05) only with that of zinc and manganese. There was a highly significant (p < 0.001) inverse correlation between the percentage cadmium absorbed and body iron stores measured as serum iron, percentage iron saturation, and ferritin. Mean whole blood concentrations were 138 µg/1 for lead and 0.79 µg/1 for cadmium. The negative balances observed in these elderly people were very different from the positive balances found in a previous similar study in children.

Overland Flow for Iron Removal From Potable Water

Overland flow, an effective wastewater treatment process, can also be used for potable water treatment. Many groundwaters contain excessive amounts of ferrous iron that result in a water of poor aesthetic quality. The natural reaeration that occurs during overland flow oxidizes ferrous iron to the more insoluble ferric form. The resulting precipitate then settles on the slope. An existing overland‐flow treatment system in Salo, Finland, achieves 97 percent iron and manganese removal. A brief description of that treatment system is presented.

NUMERICAL ANALYSIS OF A CHRONOSEQUENCE INCLUDING AN ASSESSMENT OF VARIABILITY

One hundred and eighty-three soil samples from 60 pits were collected from a sequence of moraines located in front of the Robson Glacier, Mt. Robson, British Columbia. Univariate analysis of variance, oblique rotation factor analysis, and nonlinear regression were employed to ascertain the major processes operating on the moraines and to determine whether expected trends were masked by the variability of the parent material. Soil properties which varied significantly with depth and moraine age included organic carbon, nitrogen, and pH. Assumed to be functionally related, these properties were also identified with one of two significant factors from the factor analysis. The values for organic carbon and nitrogen were fitted to nonlinear equations involving an exponential term for depth and a logistic term for time; the resulting correlation coefficients were 0.89 and 0.88, respectively. Percent calcium carbonate equivalent, percent iron plus aluminum by citrate-bicarbonate-dithionite extraction, percent iron plus aluminum by pyrophosphate extraction, percent sand, and percent clay showed generally little or no relationship to depth and age. These properties were related to the second factor from the factor analysis, which was identified with water infiltration and abiotically induced carbonation. The absence of stronger depth and age trends for these properties was considered a result of a high degree of variability within the parent material. Key words: Chronosequence, chronofunction, pedogenesis, soil development, soil sequence, soil nitrogen

Effects of Iron Status and Soy Protein on Iron Absorption by Rats

The effects of iron nutrition and soy protein on iron absorption by rats was studied. Rats were fed semipurified diets containing either 0, 5, or 20 µg of added iron per gram of diet to obtain groups with different iron status. After 3 weeks the rats had mean hemoglobin concentrations of 7.0, 10.7 and 13.2 g/dl, respectively. As the rats became more anemic, percent iron absorption from casein and soy protein diets increased. The relative availability of iron from soy compared with casein-based diets was 70 to 90%. Iron status did not affect the relative iron availability among treatments. The rat trials did not indicate any significant differences between iron absorption from meals containing soy flour (SF), soy protein concentrate (SC) or soy protein isolate (SI) regardless of the iron status of the rat. These studies do not support the hypothesis that the subject's iron status will affect the relative availability of iron from foods. Recent human iron absorption studies suggest that relative iron availability from meals containing soy proteins is lower than expected based on rat studies. Furthermore, differences in iron availability between soy flour and soy isolate observed in human studies are not apparent in these rat studies.

Inhibition of food iron absorption by coffee

Dual isotope studies were performed in iron replete human subjects to evaluate the effect of coffee on nonheme iron absorption. A cup of coffee reduced iron absorption from a hamburger meal by 39% as compared to a 64% decrease with tea, which is known to be a potent inhibitor of iron absorption. When a cup of drip coffee or instant coffee was ingested with a meal composed of semipurified ingredients, absorption was reduced from 5.88% to 1.64 and 0.97%, respectively, and when the strength of the instant coffee was doubled, percentage iron absorption fell to 0.53%. No decrease in iron absorption occurred when coffee was consumed 1 h before a meal, but the same degree of inhibition as with simultaneous ingestion was seen when coffee was taken 1 h later. In tests containing no food items, iron absorption from NaFeEDTA was diminished to the same extent as that from ferric chloride when each was added to a cup of coffee. These studies demonstrate that coffee inhibits iron absorption in a concentration-dependent fashion.

RBC Zinc Protoporphyrin to Screen Blood Donors for Iron Deficiency Anemia

We evaluated a rapid RBC zinc protoporphyrin (ZP) test in 1,147 male and 615 female blood donors to study its value in screening for evolving iron deficiency anemia. Fifteen men (1.8%) and 32 women (7.9%) who returned to donate were found to be anemic. A matched sample analysis between anemic and nonanemic donors demonstrated significant differences in serum ferritin levels, percent iron saturation, and the RBC ZP level from samples collected during the initial evaluation. Red cell ZP correlated well with the natural logarithm of serum ferritin in both men and women who later became anemic. The predictive value of RBC ZP levels compared favorably with that of the serum ferritin level. We also observed a strong association between the yearly donation frequency and RBC ZP concentration. These findings indicate that predonation RBC ZP testing may be useful in screening for iron depletion and potential risk of anemia in blood donors.

ADSORPTION OF SOME MONOHYDROXYBENZENE DERIVATIVES BY SOILS

Natural soil materials react with derivatives of benzene in water under saturated conditions slowly, with equilibration times of up to 5 days. The Freundlich isotherm equation fits best those water-phenol-soil systems in which few soil properties dominate. For the fine-textured B horizon soils used in this experiment, percentage iron oxides and solution pH were found to be the most important factors related to adsorption of these phenols by soils. Molokai clay had the highest adsorption rate of simple phenols. Slightly soluble phenols, such as dimethyl and dichloro phenols, seem to be able to react better with soils than the more readily soluble phenols, such as cresols, phenol, and p-nitrophenol. In comparing Hammett (sigma) and hydrophobic (..pi..) constants with the laboratory results, we found that a high degree of correlation seems to exist between them and the behavior of these organics in soils.

Synthesis of minerals in the Cu — Fe — Bi — S system under hydrothermal condition and their phase relations

Chalcopyrite, bornite, nukundamite, intermediate solid solution, wittichenite, emplectite, cuprobismutite, and phases CuBi₃S₅ (E), Cu₈Bi₈S₁₉ (Y) and Cu₈.₄Fe₁.₂Bi₁₀.₈S₂₂ (Z) in the system Cu — Fe — Bi — S were synthesized by a temperature gradient transport method using gold tubing under hydrothermal conditions at 300 °C and 420 °C. 5m NH₄Cl aqueous solution was used as solvent and various sulfides produced by evacuated glass tube method were employed as nutrient materials. The minerals synthesized were either a single crystal or aggregates. They were identified by ore microscope and Gandolfi or Guinier camera, and electron probe methods. According to these data, bornite and wittichenite contain 13.9 weight percent bismuth at 420 °C and 1.0 weight percent iron at 300 °C, respectively, while chalcopyrite has a very small amount, less than 0.1 weight percent, of bismuth. Emplectite and cuprobismutite have the compositions of CuBiS₂ and Cu₁₀B₁₂S₂₃, respectively, and occur as a stable phase at 300 °C and at 420 °C, respectively. A four component phase, Z, was found at 300 °C and 420 °C. It is prismatic form (monoclinic) and has a = 17.483 Å, b = 3.902 Å, c = 12.869 Å and β = 108.11° cell parameters. The stable assemblages formed at 300 °C were as follows : chalcopyrite + bornite + wittichenite + nukundamite, chalcopyrite + wittichenite + nukundamite + phase Z, wittichenite + emplectite + phase Z + phase Y, wittichenite + nukundamite + phase Z + phase Y, chalcopyrite + nukundamite + phase Z + phase Y, chalcopyrite + phase E + phase Z + phase Y, emplectite + phase E + phase Z + phase Y, intermediate solid solution + pyrrhotite + bismuthinite + Bi etc. The chalcopyrite˗wittichenite assemblage which is often found in natural ore occurs at 300 °C, but it disappears at 420 °C because the assemblages of bornite˗nukundamite˗phase Z and bornite˗nukundamite˗cuprobismutite become stable.

Day-to-day variation in serum ferritin concentration in healthy subjects.

We report our observations on day-to-day variation in serum ferritin, serum iron, total iron-binding capacity, and percent saturation of binding proteins with iron in 13 ostensibly healthy subjects during five weeks. The average intrasubject coefficients of variation were 14.5, 28.5, 4.8, and 28.0%, respectively. Precision studies on control samples showed greater within-assay and between-assay analytical variation for serum ferritin than for serum iron or total iron-binding capacity. Evidently, serum ferritin varies less in a given individual from day to day than do serum iron and percent iron saturation. Thus, a single measurement of serum ferritin may be a more reliable index of iron stores than an isolated determination of either serum iron or percent iron saturation.

Depressed 59Fe Absorption due to Dietary Aflatoxin

This study investigated the relationship between 59Fe absorption and the anemia associated with aflatoxicosis in commercial broilers. A level of 0 or 5 μg of aflatoxin per gram of diet was fed for a 21 day period beginning at 1, 7, 14, or 21 days of age in each of two trials. Packed cell volume (PCV) and percent retention of an oral dose of 59Fe were determined. The feeding of aflatoxin resulted in an anemia when fed from 0 to 3 or 1 to 4 weeks of age. At the conclusion of these treatment periods, percent 59Fe retention was significantly reduced from the controls. Aflatoxin when fed from 2 to 5 weeks of age resulted in a slight but significant depression in PCV (P<.05) with a slight but nonsignificant depression in percent 59Fe retention. At the conclusion of the 3 to 6 week treatment period both percent iron retention and PCV were greater than controls but not significantly so. The iron retentions of birds separated into high and low PCV groups within each treatment combination were compared. Although the iron retentions of the low PCV groups were lower than those of the high PCV groups, none of the differences were statistically significant. However, Pearson correlations of PCV with percent 59Fe retention were −.28 (P≤.02, n = 69) for control birds and −.19 (P≤.14, n = 58) for birds fed aflatoxin, suggesting a relationship between PCV and iron absorption.

Serum iron levels and response to hepatitis B virus

Response to hepatitis B virus (HBV) infection [HBV surface antigen (HBsAg) and antibody to HBsAg (anti-HBs)], serum iron, total iron-binding capacity, hematological status (erythrocytes, Hb, and hematocrit), and evidence of liver damage (serum glutamic pyruvic transaminase; aspartate aminotransferase, L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1) were determined for 201 patients on chronic renal dialysis. Four factors-serum iron level, transminase level, sex, and HBV response [i.e., infected-HBsAg(+) (HBsAg positive), anti-HBs(+) (anti-HBs positive), or no response]-were analyzed simultaneously to test the hypothesis that serum iron is higher in those with HBsAg in their serum than in those without HBsAg, independent of the transaminase level. Four independent, statistically significant two-factor interactions were identified. (i) Serum iron is higher in those HBsAg(+). (ii) Serum iron is higher in those with increased transaminase. (iii) Transaminase is higher in those HBsAg(+). (iv) Males are more likely to be HbsAg(+) and females are more likely to be anti-HBs(+). Also, those who are HBsAg(+) have significantly higher percent iron saturation (serum iron/total iron-binding capacity). That is, the hypothesis was supported by the findings. Several additional biological hypotheses are suggested, including a possible role of increased iron levels in susceptibility and response to HBV infection and the possible relationship between higher iron levels and the likelihood of HBV infection progressing to primary hepatocellular carcinoma. In addition, further tests of the initial hypothesis in nonhospitalized populations with endemic HBV infection are proposed.

The Relationship between Marrow Iron Stores, Plasma Ferritin Concentrations and Iron Absorption

The percentage absorption from a 3 mg dose of ferrous iron was measured in 50 subjects with iron stores that varied over a wide range. Iron status was assessed by a number of measurements, including the haemoglobin concentration, the plasma iron concentration, the total iron-binding capacity, the plasma ferritin concentration and the concentration of non-haem iron in the bone marrow. There were good inverse correlations between the log percentage iron absorption and both the log marrow non-haem iron concentration (r -0.94; P less than 0.001) and the log plasma ferritin concentration (r -0.78; P less than 0.001). In addition, there was a positive ferritin concentration (r +0.84; P less than 0.001). These results suggest that reticuloendothelial iron stores represent an important determinant of iron absorption and that their size can be guaged from the plasma ferritin concentration.

An in vitro method for predicting the bioavailability of iron from foods

An in vitro method for the determination of availability of nonheme iron from foods and diets was investigated. Food was extracted with pepsin-HCl at pH 1.35 and subsequently the pH was adjusted to pH 7.5 and filtered. Ionizable iron was determined in the pH 7.5 filterate by the α, α′-dipyridyl method. The percent ionizable iron at pH 7.5 in a number of diets was shown to correlate highly with percent iron absorption from the same diets observed in the adult males. Ionizable iron at pH 7.5 was shown to increase in presence of ascorbic acid and meat extract while it decreased in presence of phytate and tannins, similar to the effects of these factors on iron absorption in human subjects. Based on these observations it is proposed that ionizable iron at pH 7.5 determined as described in this study can be used as a reliable measure of bioavailability of nonheme iron in foods

Iron Absorption From Human Milk, Simulated Human Milk, and Proprietary Formulas

Studies from our laboratory have shown that iron is better absorbed from human milk than from cow milk and that human milk can provide insufficient iron for infants during their first year. We compared iron availability from human milk with that from other formulas and determined the factors responsible for its superiority. Adults were fed 100 ml of human milk, simulated human milk, simulated human milk containing added lactoferrin, two commercial formulas containing iron, 12 mg/qt, and human milk that had been boiled. The simulated human milk resembled human milk in concentration of protein, fat, carbohydrate, iron, total minerals, calcium, and phosphorus. Iron 59 was added to each feeding and iron incorporation into RBCs was determined 14 days after each feeding. Percent iron absorption was highest from human milk and lowest from the commercial formulas. The simulated human milk supported a 9.0% absorption; addition of lactoferrin reduced this to 4.7%. Net iron absorption was 0.12 mg/liter from human milk and 0.40 and 0.37 mg/liter from the iron-enriched commercial formulas. Absorption of iron from boiled human milk was the same as from the unboiled milk. This study confirms the unique ability of human milk to promote iron absorption. Simple manipulation of the protein, fat, lactose, calcium, phosphorus, or lactoferrin content of proprietary milk did not reproduce the iron absorption demonstrated with human milk.

Effects of Dietary Protein, Glycine, and Tryptophan on Iron Metabolism in the Growing Chick

Experiments were conducted to determine the effects of feeding diets low in protein, glycine, or tryptophan on iron metabolism in the growing chick. Three-day-old chicks, which were fed the experimental diets to 2 weeks of age, were given orally a solution of 59FeSO4 in order to determine the percentage of iron absorbed and excreted (determined by the fecal recovery method) and iron utilized and stored (determined by the radioactivity retained per unit liver, gastrocnemius muscle, and whole blood) 7 days post dose administration. The feeding of diets low in protein (5.4%, 8.5%, or 10.8%) or tryptophan (0.12%) but adequate in iron to growing chicks caused: a marked reduction in growth, rate of erthropoiesis, and percentage iron absorption; an excessive increase in iron deposited in the liver and muscle, and percentage iron collected in the excreta; and anemia which was attributed to the deficiency of protein or tryptophan respectively, in the diets fed. The feeding of diets low in glycine (0.33%) but adequate in iron caused: a marked reduction in growth and percentage iron, absorption, and a transitory increase in percentage of iron excreted without causing anemia or affecting the distribution of absorbed iron in liver, muscle and blood. The total plasma protein concentration was reduced in protein deficient chicks, but was not affected by a tryptophan or glycine deficiency.

Relationship of Day-to-day Variation of Serum Iron Concentrations to Iron-binding Capacity in Healthy Young Women

Biologic intra-individual variations in concentrations of serum iron and serum iron-binding capacity were determined for nine healthy young women in a double experiment. In each of two series approximately one month in duration, venipunctures were performed three times per week. All serum specimens were assayed for iron concentration and iron-binding capacity. The average intra-subject day-to-day biologic variations for the group in terms of coefficient of variation (CV) were 29.3% for serum iron and 8.8% for iron-binding capacity. No significant difference in variances was found for any subject in serum iron concentrations from series I to series II. Only one subject had a significant positive correlation between iron concentrations and iron-binding capacity values. Percentage iron saturation was computed for each iron and iron-binding capacity combination, and the average intra-subject CV was of the same order of magnitude as the CV for serum iron. The clinical significance of an isolated serum iron result in view of the dramatic intra-subject day-to-day variability is discussed.

Mineralogic and Petrologic Implications of Viking Geochemical Results From Mars: Interim Report

Chemical results from four samples of martian fines delivered to Viking landers 1 and 2 are remarkably similar in that they all have high iron; moderate magnesium, calcium, and sulfur; low aluminum; and apparently very low alkalies and trace elements. This composition is best interpreted as representing the weathering products of mafic igneous rocks. A mineralogic model, derived from computer mixing studies and laboratory analog preparations, suggests that Mars fines could be an intimate mixture of about 80 percent iron-rich clay, about 10 percent magnesium sulfate (kieserite?), about 5 percent carbonate (calcite), and about 5 percent iron oxides (hematite, magnetite, maghemite, goethite?). The mafic nature of the present fines (distributed globally) and their probable source rocks seems to preclude large-scale planetary differentiation of a terrestrial nature.

Mucosal Iron Retention and Plasma Iron Absorption in the Duodenum and Jejunum of Dogs

Two groups of non-anemic dogs, one with normal tissue iron stores and one with decreased tissue iron stores, underwent a surgical construction of two equal segments of duodenum and jejunum. A solution of 0.1 mg ferrous sulfate and 1 mg ascorbic acid was injected into the lumen of each segment. The solution for the duodenal segment contained 30 muc of iron59, for the jejunum segment 60 muc of iron55. The solutions were left in the segments for 2 1/2 hours before washout. On the 14th postoperative day, iron59 and iron55 radioactivity per ml/RBC was measured, and iron uptake by segments determined in two ways. Bone marrow, liver, and spleen were histologically assessed of iron stores. In dogs with normal iron stores, percent iron retained was slightly higher in jejunum that duodenum. In dogs with decreased iron stores percent retention was always higher in duodenum; in this group iron retained was about four times higher than in dogs with normal iron stores. This indicates that mucosal uptake of iron from lumen and mucosal transfer of iron from plasma vary inversely with body iron stores, but compared to mucosal uptake, mucosal transfer is more restricted to duodenum, more affected by body iron stores, more limited, and more crucial to regulation of iron absorption.