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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Work performance on a treadmill has been evaluated in normal and iron-deficient rats. Anemia was removed as a variable by adjusting the hemoglobin of all animals to the same concentration. At a hemoglobin compatible with normal work performance, iron-deficient animals showed a marked impairment of running ability as compared to control animals. Iron therapy corrected the disability within 4 days. Concentrations of the cytochrome pigments and myoglobin, and rates of oxidative phosphorylation with pyruvate-malate, succinate, and alpha-glycerophosphate as substrates were all reduced in mitochondrial preparations from skeletal muscle of iron-deficient rats, but only the rate of phosphorylation with alpha-glycerophosphate as substrate increased significantly and in parallel with the recovery in work performance of the iron-deficient rats treated with iron dextran.
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PMID:Iron deficiency in the rat. Physiological and biochemical studies of muscle dysfunction. 95 78

In this review the effects of carbon monoxide on tissular oxygenation, at doses which are compatible with life, are considered. In a first section the relative CO-O2 affinity (M*) of various O2 carrying proteins is compared; M* is about 220 for hemoglobin, 20-25 for myoglobin and close to unity for cytochrome oxidases. Thus most of the acute CO toxicity should not be considered as due to malfunction of the intracellular respiratory chain. In addition the differences in M* are caused more by the changes in O2 affinity than by those in CO affinity. The second section deals with the changes in the O2 equilibrium curve (OEC) induced by the presence of HbCO in blood, i.e. the hyperbolization of this curve due to the progressive loss of allostery due to the preferential binding of CO to Hb. The functional importance of this phenomenon lies in the fact that the lower part of the OEC is shifted to the left, whereas the upper part is shifted to the right to an extent which depends upon the amount of HbCO. Thus the effects of the so-called CO anemia are considered to be due both to the reduction of functional Hb and to the reduced partial pressure in the hypoxic range of the OEC. The third section presents recent data concerning the effect of HbCO on the VO2max of the isolated gastrocnemius preparation. The results were obtained in hypoxia under conditions where perfusion and arterial O2 content, i.e. O2 delivery, were the same with and without 30% HbCO. The salient finding is a 26% reduction of VO2max under conditions of CO anemia as compared to hypoxia alone. Interestingly, the PO2 of the venous effluent of the muscle is found to be the same in both cases which leads to the interpretation that it is not the reduction of the mean capillary PO2 but rather a decrease of the blood-to-mitochondria O2 conductance which causes the fall in VO2max.
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PMID:The effect of carbon monoxide on respiration. 217 93

A case of severe acute rhabdomyolysis (RML) is reported which was caused by marked hypokalemia associated with long-lasting diarrhea. Since the patient not only had severe muscular symptoms but also intense hemorrhagic diathesis and anemia, the first diagnosis on admission was acute leukemia. Due to the increasing occurrence of acute RML associated with different clinical conditions, including hematologic disorders, the hematologist should keep in mind the possibility of RML, both as a primitive disorder or complication, and require CPK and myoglobin assay routinely.
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PMID:[Generalized hemorrhagic diathesis and anemia of sudden onset caused by rhabdomyolysis diagnosed as acute leukosis]. 219 28

In sports, vitamins along with minerals, particularly iron, and the energy nutrients such as carbohydrates, are considered especially important. Frequently single or multiple vitamins in combination with other active substances such as iron, other minerals or carbohydrates are administered. In sports, vitamins are added to carbohydrate mixtures or electrolytes enriched with vitamins are offered and frequently used. There is no doubt that due to the numerous effects of vitamins, a connection must exist between the vitamin status and athletic performance capability. It can be concluded that vitamin deficiencies have a negative effect on physical and mental performance. The release of energy can only attain its maximum output when the organism has the required substances at its disposal. Iron is of central importance among these active substances, since its presence in haemoglobin is essential for the transport of oxygen and carbon dioxide, makes it possible for myoglobin to function as an oxygen supply depot and guarantees the functioning of internal respiration in the respiratory chain and various key enzymes. Muscle training increases not only the respiratory chain but also several other iron-rich enzymes. This makes even more astonishing the fact that a variety of recently published articles report on iron deficiency among athletes. The effect of the iron deficiency with anaemia (sports anaemia) is manifest in a reduction of aerobic capacity with an increase in lactate acidosis, greater fatigue, loss of appetite, muscular cramps and vasomotor disturbances.
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PMID:[Effect of vitamins and iron on performance and recovery in humans and in sports anemia]. 360 97

Two experiments were designed to study the iron (Fe) status in veal calves (62 intact males) fed and held on straw. In experiment 1, two groups were fed 20 mg Fe/kg milk replacer (MR) and held unattached on rye or barley straw litter. In experiment 2, groups were fed 20 mg Fe/kg MR and held unattached on rye straw litter or on sawdust or attached on wooden slatted floors without straw litter or were fed 50 mg Fe/kg MR and held unattached on sawdust. Fe concentrations in tested straw sorts (rye, barley, wheat, triticale) were similar and ranged from 15 to 85 mg Fe/kg dry matter. Growth performance and health status were not significantly influenced by Fe intake through MR or straw. Straw intake in the group fed straw was greater (P < 0.01) at the end than at the start of the growth period, but intake of different straw sorts was similar. Calves fed 20, but not those fed 50 mg Fe/kg MR, developed marked hypoferraemia, but only moderate anaemia. Total iron binding capacity (TIBC) was significantly (P < 0.05) and transferrin (Tf) concentration was numerically higher in calves fed 20 than in those fed 50 mg Fe/kg MR on slaughter day. TIBC and Tf were positively correlated (r = 0.63). Haemin concentration and lightness of m. rectus abdominis were significantly (P < 0.01), whereas myoglobin concentration was numerically greater in calves fed 50 than in those fed 20 mg Fe/kg MR. In conclusion, haematological and blood chemical parameters and meat colour were influenced only by high Fe intake through MR, but not if calves were held on straw litter or were fed straw.
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PMID:Iron status, erythropoiesis, meat colour, health status and growth performance of veal calves held on and fed straw. 781 37

Normal and anemic dog gracilis muscles were compared at equal O2 uptake rates (VO2) to locate the principal site of resistance to diffusive O2 transport. Anemia halved the hematocrit and the number of red blood cells per square millimeter of muscle cross section. Flow doubled in anemia, and flow times arterial O2 content, PO2 of effluent blood, and O2 extraction per red blood cell were approximately the same as control. Nevertheless, intracellular PO2 was significantly lower in anemia. At any instant the aggregate red blood cell surface area for O2 release was about half normal. Because the flux (VO2) was the same as control, the driving force for diffusion from red blood cell to myocyte should have doubled. An estimate of the total driving force from red blood cell to mitochondria was greater in anemia. This increase was much less than a factor of 2 because lower intracellular PO2 increases myoglobin-facilitated diffusion, thus decreasing resistance inside the myocyte. The role of myoglobin and the coupling of convective to diffusive transport are discussed. We conclude that the principal resistance to O2 diffusion lies outside the myocyte.
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PMID:Resistance to O2 diffusion in anemic red muscle: roles of flux density and cell PO2. 821 21

Iron deficiency is common in adolescents. This age-group needs more iron owing to the spurt of growth in puberty, and, in girls, because of menstrual losses, and in the event of pregnancy. In boys there is a normal rise in haemoglobin level from about 13 to about 15 g/100 ml, and in myoglobin (muscular mass). Physical training increases the need of iron (21). In addition, poor eating habits are quite common in adolescents. There are few data in the literature on the iron status of Norwegian adolescents, but large studies from USA, Canada and Sweden have disclosed iron depletion (s-ferritin below 16 micrograms/l) with or without anaemia in 40% of adolescent girls and 15% of adolescent boys. Screening, including haemoglobin and s-ferritin determinations, is advocated.
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PMID:[Teenage iron deficiency]. 823 3

High prevalence of anemia and iron deficiency state are found among athletes. To determine the influence of sports activities on the hematological state, we have performed hematological tests and examined the iron metabolism, in addition to some serum enzyme activities and some characters of red blood cells before and after exercise in high school boy athletes. The red blood cell count, hemoglobin level, and hematocrit value were significantly lower than those in the non-athletes boy students. The serum ferritin level in the athletes was significantly lower than that in the control group and healthy adults. Iron deficiency anemia was found in 12% of the athletes. The serum haptoglobin level in the athletes was significantly lower than that in the control group and the level before exercise, suggesting intravascular hemolysis, but the serum hemopexin level showed no difference before and after exercise, suggesting that the hemolysis was not so severe. The serum CPK and myoglobin levels showed a significant increase after exercise, but those levels were quite lower than that of muscle diseases. These findings suggest that daily exercise is closely associated with the increased risk of iron deficiency state, particularly in the high school boy athletes. The mechanism of hemolysis in athletes may partly depend on the increased fragility of iron deficiency red blood cells on mechanical strength.
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PMID:[Sport-anemia: studies on hematological status in high school boy athletes]. 874 90

A functional requirement for all hemoglobin-based oxygen carriers (HBOCs) is the maintenance of the heme-iron in the reduced state. This is necessary for the reversible binding/release of molecular oxygen and minimization of methemoglobin (Fe+3) formation. Acellular hemoglobins are especially susceptible to oxidation and denaturation. In the absence of the intrinsic reducing systems of the red blood cell, the reduced heme-Fe+2 can be oxidized to form increasing levels of methemoglobin that can give rise to free radicals and oxidative cellular damage. If acellular HBOCs are to be utilized as red cell substitutes for oxygen delivery, these carriers must be stabilized in the plasma, the carrier medium. Normal plasma contains reducing components, such as ascorbic acid and glutathione, that can afford protection to these acellular HBOCs through electron-transfer mediated processes. For these components to provide effective reduction to an HBOC, a favorable reduction potential difference must exist between the reducing agent and the HBOC. Using a modified thin-layer spectroelectrochemical method, a determination of the formal reduction potential (vs. Ag/AgCl) of several oxygen carriers, including monomeric myoglobin, tetrameric HbA and HbS, chemically cross-linked HbXL99alpha, polymerized oxyglobin (FDA approved for canine anemia), and the natural cross-linked polymeric Lumbricus hemoglobin, have been determined. In contrast to the negative formal reduction potentials (-155 to -50 mV) obtained for Mb, HbA, HbS, HbXL99alpha, and oxyglobin, Lumbricus hemoglobin exhibited a positive formal reduction potential (approximately 100 mV). These results may help explain the greater effectiveness of the tested reducing agents to reduce met Lumbricus hemoglobin, compared to the other HBOCs, back to the required reduced form necessary for physiological binding/release of oxygen. Each reducing agent was capable of reducing met Lumbricus hemoglobin to the fully reduced state, although the kinetics of these reactions were different. HbA, HbXL99alpha, and oxyglobin were only partially reduced (10 to 37%) by glutathione, beta-NADH, and ascorbic acid under similar conditions.
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PMID:Role of redox potential of hemoglobin-based oxygen carriers on methemoglobin reduction by plasma components. 1200 Feb 25

Fe is an essential component of haem in myoglobin and accounts for 70 % of haemoglobin. The balance of Fe, unlike that of other metals such as Na or Ca, is regulated solely by gastrointestinal absorption, which itself depends on the bioavailability of Fe in food, i.e. the chemical Fe species. Factors that maintain Fe homeostasis by modulating Fe transfer through the intestinal mucosa are found at the luminal, mucosal and systemic levels. Fe deficiency and its consequence, Fe-deficiency anaemia, form the commonest nutritional pathology in pregnant women. The current gold standard to detect Fe deficiency remains the serum ferritin value. Previously there was general consensus against parenteral Fe administration, i.e. parenteral Fe was only recommended for special conditions such as unresponsiveness to oral Fe, intolerance to oral Fe, severe anaemia, lack of time for therapy etc. However, especially in hospital settings, clinicians regularly face these conditions but are still worried about reactions that were described using Fe preparations such as Fe-dextrans. A widely used and safe alternative is the Fe-sucrose complex, which has become of major interest to prevent functional Fe deficiency after use of recombinant erythropoietin Numerous reports show the effectiveness and safety of the Fe-sucrose complex. Good tolerance to this Fe formulation is partly due to the low allergenic effect of the sucrose complex, partly due to slow release of elementary Fe from the complex. Accumulation of Fe-sucrose in parenchyma of organs is low compared with Fe-dextrans or Fe-gluconate, while incorporation into the bone marrow for erythropoiesis is considerably faster. Oral Fe is only started if haemoglobin levels are below 110 g/l. If levels fall below 100 g/l or are below 100 g/l at time of diagnosis, parenteral Fe-sucrose is used primarily. In cases of severe anaemia (haemoglobin <90 g/l) or non-response to parenteral Fe after 2 weeks, recombinant erythropoietin is considered in combination. By using parenteral Fe-sucrose in cases of severe Fe deficiency, anaemia during pregnancy is treated efficiently and safely according to our results and rate of blood transfusion could be reduced considerably to below 1 % of patients per year.
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PMID:Parenteral iron therapy in obstetrics: 8 years experience with iron-sucrose complex. 1211 22


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