Peter S. Davis

CHANGE IN GASTRIC IRON-BINDING PROTEIN (GASTROFERRIN) DURING IRON-DEFICIENCY ANÆMIA

Abstract The concentration of the iron-binding protein gastroferrin in gastric juice was considerably reduced in iron-deficiency anaemia caused by blood-loss. When haemoglobin values were restored, either by blood-transfusion or by normal blood regeneration, the gastroferrin levels returned to normal. The results support the concept that the gastroferrin production is concerned with the regulation of iron absorption in health: normal levels acting to inhibit the absorption of the excessive amounts of iron present in a normal diet, and reduced levels permitting enhanced absorption of iron in iron deficiency.

Gastric iron binding in haemochromatosis, secondary iron overload, cirrhosis, and diabetes.

Abstract The iron-binding ability of fasting gastric juice was studied in normal subjects and in patients with haemochromatosis, iron overload due to a variety of causes, hepatic cirrhosis, and diabetes mellitus. In patients with haemochromatosis, negligible amounts of iron were bound, whereas in the other patients values were similar to those found in normal subjects. This absence of iron binding appears to be peculiar to idiopathic haemochromatosis, and may account for the excessive absorption of dietary iron.

A radiometric assay of copper binding in biological fluids and its application to alimentary secretions in normal subjects and Wilson's disease☆

A simple radiometric assay for the determination of copper binding by synthetic chelating agents and complex biological fluids has been developed. The assay makes use of the fact that most ionic copper compounds are insoluble at pH 8.0, whereas most copper—chelate compounds resist hydrolysis and remain soluble at this pH. The assay procedure has been described and the linearity, sensitivity and precision of the method determined for EDTA and l-histidine. Application of the procedure to saliva, gastric juice, duodenal aspirate and bile from normal persons demonstrated in each the presence of copper binding components which form soluble complexes under the alkaline conditions imposed in vitro. The problems inherent in quantitation of values from biological fluids are considered, especially in relation to gall bladder bile which bound greater amounts of copper than the other intestinal secretions examined. The values obtained from patients with Wilsons disease were the same as observed in normal subjects, although samples of bile were unavailable for assay. It is proposed that the endogenous ligands in gastrointestinal secretions may be involved in the control of mucosal uptake of dietary copper.

Studies in search of modifiers of the toxicity of mercurials and speculations on its biochemical mechanism

Abstract Experiments were conducted to ascertain if exposure of goldfish ( Carassius auratus ) to l -cysteine, l -glutathione, calcium pantothenate, pantethine, or coenzyme A modifies the acute toxicity of mercuric and methylmercuric chlorides. It was found that exposure to l -cysteine, together with a mercurial, protected all the fish despite substantial accumulations of mercury by them. Coenzyme A was effective against methylmercury when exposure was simultaneous with the mercurial, while it was effective against mercuric chloride when exposure was 24 hr before exposure to the mercurial. These observations are consistent with our hypothesis that at least part of the toxic action of mercury is due to its combination with coenzyme A.

Effect of ascorbic acid on biotransformation and modification of the toxicity of mercurials in goldfish (Carassius auratus).

Ascorbic acid mediated a small but significant degradation of methylmercury to inorganic mercury in goldfish (Carassius auratus) and reduced the toxicity of mercuric chloride despite its substantial conversion into organic form.

Salicylates and Iron Absorption: Competition of salicylate and gastric juice for iron

Summary The administration of a salicylate-iron complex in a 50:1 molar ratio did not alter radioiron absorption in normal subjects. Although salicylate has the ability to chelate iron in vitro, its ineffectiveness in vivo was shown to be due to the stronger affinity of gastric juice for iron. A high molecular weight protein fraction in gastric juice successfully competes with salicylates for the iron, rendering the salicylate ineffective in iron absorption. No evidence was found to support the proposal that a mechanism for a salicylate anemia is the formation of an inhibitory iron-salicylate complex.