1964 Volume 13 Issue 3 Pages 225-233
A modified method for the determination of 59Fe and 55Fe. The 59Fe activity is measured in a 2in×2 in NaI (T1) well crystal. This detector is not sensitive to the soft X rays of55Fe. The background is 100 cpm at efficiencies of 22% (liquid samples) and 6.5% (electroplated samples) for59Fe. The 55Fe activity is measured from electroplated samples in a 3mm×1 3/4 in NaI (T1) crystal covered with 0.15 mm beryllium, which is preferentially sensitive to55Fe. In this condition the efficiency is 4.4% for55 Fe and 5.7% for 59Fe, and the background is 150cpm.
By means of a double radioisotope technique permitting determinations of the total amount of iron absorbed as well as the absorption rate, iron absorption was studied in a normal subject, in patients with iron deficiency, and in gastrectomized subjects with or without iron deficiency.
When one mg radioiron as iron sulfate solution was administered orally, the shape of the plasma radioiron curve suggested that it might express the deference of two exponential functions. As a result, a new analytic method was devised to study kinetics of iron absorption. The iron absorption value calculated using this method was in good accord with that using the method of Hallberg and Sölvell. The initial absorption rate varied from 134 μg/hour to 3830 μg/hour in different subjects. Significant correlation was observed between the iron absorption value and the plasma iron disappearance half time, and between the rate constant from intestine to plasma and the serum iron level.
In the patients with iron deficiency, the amount of iron absorbed into plasma during several hours was larger than in normal subjects, whereas the amount temporarily stored in the mucosa was not larger.
In a gastrectomized anemic patient, when ferrous sulfate was given orally, the maximal absorption rate per 15 minutes was observed during the first 15 minutes following iron administration, and the absorption was not disturbed as compared to non-gastrectomized subjects, while the absorption of iron combined with egg protein was almost zero. These results may indicate that in some of gastrectomized subjects, although the ionization of iron from egg iron is disturbed, the absorption of iron salts in the intestine is not disturbed. Furthermore, the transportt of iron to the intestine is rapid.
