Maurice E. Shils

Serum Immunoglobulin G in the Magnesium-Depleted Rat

Summary Magnesium-depleted rats had decreased levels of serum or plasma IgG. Twenty-four hours after repletion with magnesium and feeding of control diet, serum IgG levels were increased above control values and continued to rise markedly during the following 14 days.

Comparison of Magnesium Deficiency in the Rat and Mouse

Summary A comparative study has been made of the reactions of mice and rats subsisting on the same magnesium-deficient diet. Deficient young male rats developed the classical erythema, hyperirritability and tonic-clonic convulsions. While there was a high mortality with the convulsions, a good proportion recovered. Deficient male mice did not develop erythema or hyperirritability; they did convulse, but it was a single violent spasm wtih almost immediate death and rare survival. The deficient rats were either normocalcemic or hypercalcemia whereas the mice were hypocalcemic. There was a positive correlation between the plasma magnesium and calcium in the deficient mice. Although growth of mice receiving 5 mg% of magnesium in their diet was close to that of controls with 40 mg%, the plasma magnesium and calcium remained low for approximately 5 weeks. Renal glomerular dysfunction and calcification did not occur in depleted animals in either species.

INTRAVENOUS FEEDING. NUTRITIONAL ASPECTS.

Intravenous feeding is essential in certain medical emergencies, and is often used for brief periods. Based on adequate clinical evaluation, relatively prolonged maintenance by the parenteral route is also feasible as an interim measure with the goal of restoring oral intake.Recognition and proper management of altered requirements in intravenous feeding are a continuing challenge to the physician. Nutritional aspects are reviewed in relation to caloric needs; amino acid, carbohydrate and fat utilization; and vitamin and mineral requirements, as well as the available sources of each.

Cycloheximide Inhibition of Gastric Secretion in the Rat

Summary Cycloheximide, at a dose (0.5 mg/kg, i.m.) which is known to inhibit incorporation of amino acids in the proteins of the stomach was found to decrease gastric secretory volume and acid and pepsin production in rats with pylorus ligation. When various stimuli to gastric secretion (alcohol, insulin, gastrin pentapeptide, and 2-deoxyglucose) were given, there were smaller absolute responses in the cycloheximide-treated rats than in controls.

Cycloheximide Effect on Vitamin B12 Absorption and Intrinsic Factor Production in the Rat

Summary Cycloheximide given parenterally to rats delays gastric emptying of vitamin B12-57Co, decreases the secretion rate of intrinsic factor and inhibits absorption of the vitamin in the small intestine even in the presence of intrinsic factor.