Hemoglobin incorporation

In the hemoglobin incorporation method, absorption is estimated from the amoiint of tracer appearing in the blood. The principle of this method is based on the observation that absorbed iron is incorporated into circulating hemoglobin 10 to H days after dosing (7). A factor of 75% to 90% is usually introduced to correct for the incomplete utilization of absorbed iron for hemoglobin synthesis in normal subjects (8). 

The aim of this study was to further explore the potential and limitations of using stable iron isotopes as tracers and EI-MS in absorption studies. Procedures were developed for preparing iron acetylacetonate from both blood and fecal samples for mass spectrometric analysis. The precision and accuracy of ion abundance measurements were evaluated. In vivo use of stable iron isotope tracers was tested with a human study in which 54pe and 57pe were given orally and absorption was estimated with the fecal monitoring and hemoglobin incorporation methods. 

Hemoglobin incorporation method 6.73 mg 54Fe in orange juice... 

The Hemoglobin Incorporation Method. The hemoglobin concentration of each blood sample was determined, and iron chelates were prepared for abundance measurements. The blood volume was estimated from the equation of Jarnum (24>) t... 

Table VII. Absorption of stable iron isotopes in orange juice measured with the fecal monitoring and hemoglobin incorporation...

Errors associated with iron quantification and abimdance measurements are common to both fecal monitoring and hemoglobin incorporation methods According to Janghorbani and Young (2 )> acceptable absorption estimates can be obtained if the precision of these measurements is kept below 5% The analytical procedures developed in this study are thus considered satisfactory since the relative standard deviation was 2 48% for total iron quantification and less than 2% for ion abimdance determinations ... 

In the hemoglobin incorporation method, estimation of blood volume from height and weight may introduce a 5% error (29) A... 

Comparison of Absorption Data. Little correlation was found between the absorption data obtained with the hemoglobin incorporation and fecal monitoring methods with or without correction for PEG recovery (Table VII). There are several possible reasons for this poor correlation. 

Huang, H., P. He, N. Hu, and Y. Zeng (2003). Electrochemical and electrocatalytic properties of myoglobin and hemoglobin incorporated in carboxymethyl cellulose films. Bioelectrochemistry 61, 29-38. 

Figure 6.6 UV-vis spectra of hemoglobin incorporated into the PNIPAAm brush (a) without hemoglobin, (b) with hemoglobin at 40°C, and (c) upon release of hemoglobin at 20°C. Yin et al.J. Phys. Chem. C. 2009 [67],...

In fact, the malaria parasite has a limited capacity for de novo amino acids synthesis, and its survival is dependent upon hemoglobin proteolysis. The amino acids derived from the hydrolysis of globins are incorporated into the parasite s proteins and appear to be available for energy metabolism. This digestion of hemoglobin releases heme, which is... 

Finally, a divalent iron is incorporated into the ring. This step also requires a specific enzyme, ferrochelatase. The heme b or Fe-pro-toporphyrln IX formed in this way is found in hemoglobin and myoglobin, for example (see p. 280), where it is noncovalently bound, and also in various oxidoreductases (see p. 106). 

The last column in the table lists some of the functions of minerals. It should be noted that almost all of the macroelements in the body function either as nutrients or electrolytes. Iodine (as a result of its incorporation into iodothyronines) and calcium act as signaling substances. Most trace elements are cofactors for proteins, especially for enzymes. Particularly important in quantitative terms are the iron proteins hemoglobin, myoglobin, and the cytochromes (see p. 286), as well as more than 300 different zinc proteins. 

Different iron salts provide different amounts of elemental iron, as shown in Table 33-3. In an iron-deficient individual, about 50-100 mg of iron can be incorporated into hemoglobin daily, and about 25% of oral iron given as ferrous salt can be absorbed. Therefore, 200-400 mg of elemental iron should be given daily to correct iron deficiency most rapidly. Patients unable to tolerate such large doses of iron can be given lower daily doses of iron, which results in slower but still complete correction of iron deficiency. Treatment with oral iron should be continued for 3-6 months after correction of the cause of the iron loss. This corrects the anemia and replenishes iron stores. 

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