Jiro Oyama

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.

Anatomic and Histologic Changes in Rabbits with Experimental Hypersensitivity Treated with Compound E and ACTH

Summary The experimental data indicate that Compound E markedly suppresses the pathological alterations of the Arthus reaction ordinarily produced in the rabbit by repeated injections of crystalline egg albumin. The adrenocorticotrophic hormone exerted a decidedly less marked effect. 2. Treatment with Compound E and ACTH produced atrophy of the lymphoid tissues, including the thymus and spleen, and a lymphocytopenia. These alterations were greater with Compound E and in addition, in the animals treated with this hormone, there were extensive deposition of glycogen and fat in the liver, a lipemia and focal necrosis of skeletal muscle. In the animals treated with Compound E the adrenals were small while in those treated with ACTH, the adrenals were enlarged but lacking in lipoid.

Influence of cortisone on experimental hypersensitivity and circulating antibody in the guinea pig.

Summary 1. Large doses of cortisone failed to protect guinea pigs against active or passive anaphylactic shock. These results are in agreement with those of other investigators (3,4). 2. Treatment with this hormone during period of active sensitization diminished the intensity of the Arthus reaction and the quantity of circulating antibody produced. Neither of these effects was as extensive as those observed in rabbits following the administration of comparatively smaller doses of cortisone (1,2) Similarly, the anatomic changes produced by cortisone were less striking in the guinea pig than in the rabbit (8). These findings suggest that the guinea pig is considerably more resistant to the action of cortisone. The failure of cortisone to abolish the active Arthus reaction and possibly its failure to alter active anaphylactic shock might have been related to the incomplete suppression of circulating antibody under the experimental conditions employed.

Effect of Insulin on Glucose Uptake by Mouse Diaphragm Tissue

Summary A method for estimating insulin using pooled mouse hemidiaphragms has been developed. A linear log dose-response was obtained between 30–3000 micro-units of insulin/ml. Basal glucose uptake of mouse diaphragm tissue was 2 1/2 to 4 times that of rat diaphragm tissue. Basal uptake was significantly affected by pH of medium, glucose concentration, and diaphragm size. A progressive increase in magnesium or potassium concentration of the medium suppressed the basal glucose uptake.

Particle size of antigen in relation to antibody-suppressive effect of cortisone.

Summary Rabbits were immunized with either p-bromophenylureido-BSA or similarly conjugated human red cell stroma. One-half the rabbits in each group were treated with cortisone. Antibody was measured with a p-bromophenylureido-protein other than the one used for immunization. Cortisone reduced antibody production to the conjugated BSA but affected antibody produced to the conjugated stroma but little, if at all.

Serum insulin-like activity as measured by mouse hemidiaphragm technic.

Summary The mouse diaphragm technic has been adapted to measure insulin-like activity of dialyzed serum. Compared to the response effected by insulin in KRB buffer medium alone, normal rabbit serum inhibited while beef serum albumin enhanced insulin response. Mean serum insulin level of adult rats was significantly greater than rabbits, mice, and dogs and much higher than humans. A significant elevation in serum insulin activity which persisted up to 45 minutes following injection, was found in rabbits injected intravenously with 1 unit/kg insulin.

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.