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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reports of subnormal serum ferritin values for elite athletes are widespread. Human studies evaluating performance in the ferritin-depleted state have led to a questioning of the significance of low ferritin levels for athletic performance. However, the accelerated iron metabolism and subnormal iron intake-uptake demonstrated by some athletes suggests that a point occurs in training at which the body must draw on its reserves. In consideration of this problem, serum ferritin, hemoglobin, hematocrit, serum Fe, and total iron-binding capacity levels were measured in elite Canadian female synchronized swimmers (n = 9), male speed swimmers (n = 7), and male and female speed skaters (n = 6, n = 6) over the course of two seasons of training and competition. Training sessions were monitored to document the workload carried out by each athlete. The midseason serum ferritin team values for the first and second years (mean +/- SEM) were as follows: synchro 48 +/- 10 micrograms.1 L, 24 +/- 6 micrograms.1 L; female speed skaters 57 +/- 14 micrograms.1 L, 51 +/- 7 micrograms.1 L; male speed skaters 94 +/- 27 micrograms.1 L, 72 +/- 19 micrograms.1 L; and male swimmers 66 +/- 13 micrograms.1 L, 56 +/- 7 micrograms.1 L. A significant decrease was seen in both serum ferritin and hemoglobin for the synchronized swimmers and in serum ferritin for the male speed skaters (p less than 0.05). These results suggest that a tendency exists for a decrease in serum ferritin levels from season to season.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Serum ferritin values in elite speed and synchronized swimmers and speed skaters. 223 May 36

Haematological indices and parameters of iron status were obtained from 29 normal male subjects and from 32 male blood donors. Percentage saturation of transferrin with iron and the usual erythrocyte parameters of iron status were similar in both group of subjects. The mean ferritin concentration was 64.75 ng/ml +/- 4.6 (SEM) in normal males and 49.19 ng/ml +/- 5.1 (SEM) in the male donors. This difference was statistically significant (p less than .05). Serum ferritin concentration thus appears to be a sensitive index of iron stores. The results also indicate that some blood donors may be pre-latent or latent iron deficient at the time of donation and may manifest as iron deficient after blood donation. Based on these findings, it is suggested that blood donors be given iron supplementation and those who do not meet the minimum screening haemoglobin concentration be further investigated and treated.
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PMID:Iron stores of Nigerian blood donors as assessed by serum ferritin concentration. 227 85

We measured the effect of calcium from food and supplement sources on whole-body retention of 59Fe in 19 normal postmenopausal women. Each woman received a placebo and 500 mg calcium from a mixed calcium citrate-malate salt (CCM), from orange juice plus CCM, and from milk after a test breakfast meal to which 59Fe had been added. The test meal contained 238 mg calcium. Whole-body countings of 59Fe were performed before and 30 min and 2 wk after each test meal. Retention of 59Fe was 8.3 +/- 1.1% (means +/- SEM) with placebo, 3.4 +/- 0.78% with milk, 6.0 +/- 0.97% with CCM, and 7.4 +/- 1.7% with CCM plus orange juice. When compared with placebo, milk and CCM significantly lowered iron retention (p less than 0.05) whereas CCM plus orange juice did not. The reduction with milk was greater than that with CCM (p less than 0.05) or CCM plus orange juice (p less than 0.05). The differences in the effects of these calcium sources on 59Fe retention may result from their varied contents of citric and ascorbic acids, known enhancers of iron absorption.
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PMID:Effects of different calcium sources on iron absorption in postmenopausal women. 229 34

Iron absorption from human milk and infant formula has received much attention, but experimental design problems have been common. In our study, iron retention from human milk, milk-based infant formula (IF) with and without supplemental ferrous sulfate, and IF supplemented with either human or bovine lactoferrin (Lf) was evaluated in infant rhesus monkeys. The exchange of 59Fe (III) Cl3 between the whey, casein, and fat fractions required up to 72 h to reach the same distribution as intrinsic iron, depending on the type of diet. Infant monkeys were intubated with labeled human milk or IF and counted in a whole body counter. Each infant received all five diets and was also intubated with a reference dose of 55Fe (II) ascorbate. There was no significant difference in iron retention (mean +/- SEM) from the experimental diets: human milk 32.5 +/- 5.1%; IF 32.1 +/- 8.0%; IF + Fe 23.0 +/- 3.9%; IF + human Lf 23.5 +/- 3.3%; IF + bovine Lf 22.7 +/- 4.9%. Therefore, infant monkeys absorb and retain iron similarly from human milk and infant formula. Supplementation of infant formula with human or bovine Lf resulted in similar iron retention to that of ferrous sulfate-supplemented infant formula.
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PMID:Iron retention from lactoferrin-supplemented formulas in infant rhesus monkeys. 231 47

The effect of ascorbic acid on iron retention from a diet with predicted low iron bioavailability (containing minimal meat and ascorbic acid) was investigated in iron-depleted premenopausal women. Eleven women were depleted of storage iron (indicated by serum ferritin) through a combination of diet (5.0 mg Fe/2000 kcal for 67-88 d) and phlebotomy. They then consumed a diet containing 13.7 mg Fe/2000 kcal, supplemented with placebo or ascorbic acid three times daily (1500 mg total) with meals for 5.5 wk. Ascorbic acid improved apparent iron absorption (balance method) [38 +/- 2% (means +/- SEM) vs 27 +/- 2%]. Ascorbic acid also improved hemoglobin, erythrocyte protoporphyrins, and serum iron but not hematocrit, serum ferritin, iron-binding capacity, or transferrin saturation. In iron-depleted women consuming a diet with predicted poor iron availability, ascorbic acid supplementation enhanced body iron retention for 5.5 wk.
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PMID:Ascorbic acid: effect on ongoing iron absorption and status in iron-depleted young women. 232 71

The chemical composition of high-solids basecoat paint overspray aerosols was determined as a function of particle size. Detailed information on the chemical composition of the overspray aerosols is important in health hazard evaluation since the composition and distribution within the airborne particles may differ significantly from the bulk paint material. This study was conducted in a typical down-draft paint booth equipped with air-atomized spray painting equipment. A fixed paint target was used to simulate typical overspray generation conditions and the aerosols were collected isokinetically with a seven-stage cascade impactor for size-fractionated analysis. The overspray aerosol from six paints consisted of organic paint binders with varying amounts of inorganic species as pigments or luster enhancers. These overspray aerosols had mass median aerodynamic diameters (MMAD) ranging from 2.9 to 9.7 microns. The size-fractionated paint samples collected on the impaction stages were analyzed by energy dispersive X-ray spectrometry on a scanning electron microscope (SEM-EDXRS) to identify the metallic elements. Atomic absorption spectrometry was used to determine the mass distribution of aluminum and iron as indicators of nonuniform distribution. Three of the aerosols containing aluminum were found to have bimodal distributions with most aluminum distributions having cumulative MMADs larger than the total aerosol. Iron in the aerosols was bimodal for three of the paints with all samples having an overall iron MMAD less than or equal to the overspray aerosol MMAD. Analysis using ultraviolet spectrometry revealed that the organic compounds present in the size-fractionated particulate samples consisted of a single, polydispersed mode with an MMAD similar to that of the total overspray aerosol.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Chemical distribution in high-solids paint overspray aerosols. 232 24

Nine mongrel dogs were anesthetized, paralysed, ventilated, and placed in an iron lung. Each animal was transiently connected to a spirometer and the respiratory system compliance measured by applying negative or positive extrathoracic pressures (from -20 cm H2O to +20 cm H2O in 5 cm H2O steps). A sub-lobar bronchus was wedged with a 5.5 mm bronchoscope, and a 5f Swan-Ganz catheter was inserted into the lumen of the bronchoscope; one port served to introduce a 200 ml.min-1 flow of 5% CO2 in air, the other to measure the pressure in the wedged segment. Rcoll was measured with extrathoracic pressures in the iron lung ranging from 0 to -20 cm H2O (NEP) and 0 to +20 cm H2O (PEP) in 5 cm H2O steps, and under expiratory positive airway pressure (EPAP) of 5, 10, 15, and 20 cm H2O. The maximal changes in FRC were an increase of 1009 +/- 49 ml (mean +/- SEM) with NEP and a decrease of 397 +/- 33 ml with PEP. Increasing FRC decreased Rcoll while decreasing FRC markedly increased it. EPAP induced similar decreases in Rcoll as NEP of equal pressure. This effect of EPAP was inhibited by simultaneously applying PEP of equal pressure. We conclude that resistance to collateral flow is highly dependent on lung volume, and that positive airway pressure decreases Rcoll by its effects on lung volume.
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PMID:Effects of lung volume and positive airway pressure on collateral resistance. 236 48

To determine the effectiveness of vigorous realimentation with dietary fat, 17 subjects aged 64.0 +/- 2.1 years (mean +/- 1 SEM) were pump-fed via a nasogastric tube for an average of 22 days. The diet was liquid and nutritionally complete, high in unsaturated fat (67% of energy) and in the caloric density (12.6 kJ/mL or 3 Kcal/mL) [corrected]. Advanced malnutrition was manifested by 74% of the ideal body weight, subnormal anthropometric measurements, and low serum protein levels. At an intake of 17,986 +/- 945 kJ (4068 +/- 225 Kcal [corrected]) and 344 +/- 18 g of fat per day, the rate of nutrient absorption was 93% for energy and fat and 88% for protein. An increase in the daily fecal fat to 23 +/- 6 g was not associated with diarrhea. While serum triglyceride levels remained unchanged, the total cholesterol level decreased, with a relative increase in the high-density lipoprotein level. Effective utilization of nutrients resulted in a positive nitrogen balance and increases in body weight, triceps skinfold, the midarm muscle circumference, total iron binding capacity, and serum urea nitrogen level.
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PMID:Absorptive capacity for dietary fat in elderly patients with debilitating disorders. 210 86

The effect of extrusion cooking of a bran-flour mixture on iron and zinc retention was measured in normal adults. The stable isotopes 58Fe (1.253 mg) and 67Zn (5.13 mg) were administered with 40 g nonextruded or extruded cereal with milk and isotopic retention was measured from fecal excretion over the next 4-7 d by neutron-activation analysis (Fe) and fast-atom-bombardment mass spectrometry (Zn). 58Fe retention was 15.1 +/- 2.4% (means +/- SEM) with the nonextruded meal and 16.5 +/- 2.7% with the extruded meal. 67Zn retention was 18.9 +/- 1.7% with the nonextruded meal and 18.3 +/- 1.5% with the extruded meal. Extrusion cooking had no effect on 58Fe or 67Zn retention.
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PMID:Iron and zinc absorption in human subjects from a mixed meal of extruded and nonextruded wheat bran and flour. 253 11

Starvation for 24 h causes a striking fall in glutathione content from 3.19 +/- 0.27 to 1.88 +/- 0.14 (X +/- SEM) mumol/g tissue and of GGT activity from 31.75 +/- 4.17 to 19.49 +/- 3.13 (X +/- SEM) nmol/min/mg protein in the homogenate from whole mucosa of the upper small intestinal segments. This was associated with a significant increase in GSH-Px activity and the content of lipid peroxides (measured by the thiobarbituric assay). On semi-synthetic iron-supplemented diet the activities of GSH-T and GGT were significantly decreased as compared with crude diet. On semisynthetic iron-depleted diet GSH-T and GGT activities were further depressed, but this was accompanied with an additional depression of GSH, glutathione reductase (GSSG-R), and glutathione peroxidase (GSH-Px) activities and lipid peroxide concentrations. Food deprivation significantly lowers the mucosal GSH-content and could lead to a destabilization of this system presumably by increased oxidative stress. As compared to normal "crude" diet, semisynthetic diets and oral iron depletion have been shown to cause a depression of the intestinal GSH system. As a consequence of these effects, the resistance of the small intestinal mucosa toward exogeneous dietary toxins might be reduced.
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PMID:Glutathione and its related enzymes in the small intestinal mucosa of rats: effects of starvation and diet. 256 68


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