Arthur L. Schade

Bound iron and unsaturated iron-binding capacity of serum; rapid and reliable quantitative determination.

Summary 1. New, rapid, and reliable methods for determination of siderophilin-bound iron and of iron-free siderophilin in small amounts of sera or plasma have been devised. 2. Bound serum iron is determined by adjustment of serum sample with concentrated phosphate buffer to a pH value at which constituent proteins remain in solution but siderophilin-bound iron is wholly dissociated and available to combine with a suitable chromo-genic agent, (terpyridine). Ascorbic acid is used as the iron reductant. Iron-terpyridine complex in treated serum is measured by light absorption of a test solution at 552 mμ against a treated serum control minus terpyridine. A standard iron-terpyridine curve permits ready estimation of amount of iron in original serum sample. 3. The proposed method for determination of iron-free siderophilin, or unsaturated iron-binding capacity of serum (UIBC), involves addition to serum of iron in excess of that capable of being bound, followed by direct analysis of serum sample with terpyridine as the chromogenic agent without acidification or the removal of constituent proteins. A serum control to which the same amount of iron but no terpyridine is added furnishes the necessary correction for the absorption at 552 mμ of iron-siderophilin complex in the rest sample. The difference between quantity of iron added to serum and that found to be in excess is equal to the UIBC.

Diurnal-Nocturnal Variations of Certain Blood Constituents in Normal Human Subjects: Plasma Iron, Siderophilin, Bilirubin, Copper, Total Serum Protein and Albumin, Haemoglobin and Haematocrit

THE iron content and total iron-binding capacity of the plasma are subjects of wide scientific and medical interest. Evidence is accumulating that certain diseases have a characteristic effect not only on the concentration of plasma iron and its rate of turnover (Laurell, 1952; Brendstrup, 1953) but also on the concentration of the plasma iron-binding protein, siderophilin. Iron-deficiency anaemia, malignant neoplastic disease and acute and chronic infections, with the exception of viral hepatitis, are characterized by the level of plasma iron being lower thali normal. The circulating siderophilin concentration is abnormally high in cases of iron-deficiency anaemia, sharply lowered in acute infections and somewhat less markedly depressed in chronic infections and malignancy. Several investigators, e.g., Vahlquist (1941), Hayer (1944) and Hemmelcr (1951), have reported data on the variations of plasma iron levels in normal subjects over a 24-hour period. Relatively little study has been made of the possible daily variations of their total iron-binding capacities. It was primarily with the intention of examining normal subjects in this respect that the present studies were undertaken. In addition to the plasma iron and total siderophilin lcvels of blood samples taken from twenty nornial subjects over a z4-hour test period, we estimated other blood constituents whose concentrations might be related. Total serum protein and albumin concentrations were determined in order to associate any observed variation in siderophilin, a globulin, with possible changes in total globulin concentrations. The plasma samples were analysed for their copper content to determine any possible interrelationship between plasma iron and copper levels in normal subjects, as reported by Hcilineycr, Keiderling and Stiiwe (1941) in their studies of clinical and experinientally induced infections. Bilirubin estimations were made on a number of sera to extend Laurells (1953) observations of parallel variation of morning and evening serum iron and bilirubin concentrations in normal subjects. Haemoglobin concentrations and hacmatocrit values were also determined.

Enzymic studies on ascitic tumors and their host's blood plasmas

Abstract Otto Warburgs finding that the aldolase concentration in the ascitic fluid of the Ehrlich ascites carcinoma increases significantly upon anaerobic in vitro incubation was confirmed. dba thymoma ascitic cell suspensions from dba mice were investigated under similar conditions and the observations extended to include, in addition to aldolase, both isomerase and α-glycerophosphate dehydrogenase concentrations in the ascitic fluids from tumors of different ages and in the blood plasmas of the hosts. Comparative studies were made on the Ehrlich ascites carcinoma in strain C albino mice.

Effect of Ultraviolet Radiation on Iron-binding Capacity of Plasma

Summary 1. Ultraviolet irradiation of ACD plasma and of plasma fraction IV-7 solutions inactivates the siderophilin component as measured by the loss of its specific iron-binding capacity. 2. The initial inactivation rates; whose magnitude was correlated with the absorption coefficients of the irradiated siderophilin solutions, followed essentially first order kinetics. 3. The UV inactivation rates of iron-free and iron-saturated siderophilin were found to be the same.