Wade Volwiler

Deposition in and release of vitamin D3 from body fat: evidence for a storage site in the rat

Vitamin D in all body tissues was radio-labeled by supplementing completely vitamin D-deficient weanling rats with oral vitamin D(3)-4-(14)C for 2 wk. All vitamin D was then withheld, and radioactivity and vitamin D content in a variety of organs and tissues were measured. Adipose tissue was found to contain by far the greatest quantity of radioactivity throughout the 3 month experimental period. Immediately after supplementation, half of the total radioactivity in adipose tissue corresponded to unaltered vitamin D(3), and the other half to polar metabolites and esters of vitamin D(3) and unidentified peak II. 1 month later there was approximately the same proportion but a decrease in the total quantity of each form. We conclude that adipose tissue is the major storage site for vitamin D(3) in its several forms. Unaltered vitamin D(3) was the principal storage form observed and presumably a source available for conversion to other metabolites during deprivation.

Absorption of calcium measured by intubation and perfusion of the intact human small intestine

Absorption of calcium was measured by direct intubation and perfusion of the small intestine in 10 volunteer normal adult subjects, two adults with celiac-sprue, and one with a parathyroid adenoma. A total of 60 studies were completed using one of two different levels, duodenojejunum or ileum. Solutions containing stable calcium, radiocalcium(47), and a nonabsorbable dilution-concentration marker, polyethylene glycol, were infused at a uniform rate via the proximal lumen of a triple-lumen polyvinyl tube. The mixed intraluminal contents were continuously sampled by siphonage from two distal sites, 10 and 60 cm below the point of infusion. Unidirectional flux rates, lumen to blood and blood to lumen, and net absorption of calcium for the 50 cm segment of small intestine between the two collection sites were calculated from the measured changes in concentration of stable calcium, calcium-47, and polyethylene glycol.Flux of calcium from lumen to blood in the duodenojejunum of normal subjects was appreciable even when the concentration of calcium in the perfusate was below that of extracellular fluid and, as the intraluminal concentration of calcium was increased through a range of 0.5-3.5 mumoles/ml, was positively correlated, ranging from 1.9 to 7.0 mumoles/min per 50 cm. Repeated studies of individual subjects demonstrated a consistent pattern of absorptive efficiency in each, but significant variability from person to person. Flux from lumen to blood in the ileal segment occurred at a much lower rate than that found in the proximal intestine, and there was not a significant dependence upon intraluminal calcium concentration. The opposite flux, from blood to lumen, was low both in the duodenojejunum and ileum (average 0.76 mumoles/min per 50 cm) and was independent of the intraluminal calcium concentration. Unidirectional flux, lumen to blood, from the duodenojejunum was not altered by parathyroid extract administered at the time of the infusion, but was accelerated in the subject with a parathyroid adenoma and markedly reduced in the two subjects with celiac-sprue.

Gastrointestinal malabsorptive syndromes

Abstract The broad syndromes of gastrointestinal malabsorption are discussed, with special reference to etiology, pathologic physiology, differential diagnosis, laboratory investigation and principles of treatment. Selected important points in therapy are illustrated with detailed balance studies. A classification of the steatorrheas based upon the biochemical processes involved in normal fat digestion and absorption is presented.

PAPER ELECTROPHORESIS OF SERUM PROTEINS: PHOTOMETRIC QUANTITATION AND COMPARISON WITH FREE ELECTROPHORESIS

Methods for electrophoretic separation of amino acids, peptides and proteins on filter paper were developed independently by several investigators (1-5) during the years 1948-50. The major protein components of serum could be separated satisfactorily by this principle. The serum proteins on the paper were stained with dye; by cutting the paper into segments and eluting the dye, the amount bound in each segment could be estimated and an electrophoretic pattern constructed. The quicker procedure of photometric quantitation of the resolved serum components directly from the paper strip was introduced by Grassmann, Hannig, and Knedel (6, 7). Variables which affect electrophoretic movement of protein and peptide in a paper supported buffer medium include variations in potential gradient, temperature, pH, ionic strength and nature of the buffer used, thickness of the filter paper, evaporation, time of run, and nature of the protein itself. Paper electrophoresis is well established as a research technique, having been successfully used in serum protein and lipid analysis (2-20), identification of the iron-binding globulin (21), study of gastric mucins (22), serum transport of thyroglobulin (23) and identification of abnormal hemoglobins (24, 25). This report relates experiences with the GrassmannHannig and Durrum methods of paper electrophoresis of serum proteins and photometric measurement of the amount of dye bound by the serum protein fractions. The significance of results ob-

The Effect of Cortisone Upon Absorption of Protein, Fat, and Calcium in Idiopathic Steatorrhea

Summary The case history of a young female with severe idiopathic steatorrhea is described. Metabolic balances for fat, nitrogen and calcium, and intestinal absorption tests were studied before and during emergency ACTH and cortisone therapy. Dramatic clinical response was paralleled by a rapid fall in daily stool weight and prompt improvement in fat, nitrogen, and calcium absorption. Calcium balance data suggest that very large doses of oral vitamin D may be ineffective in relapses of sprue and that cortisone may promote calcium absorption independently of the action of vitamin D.

Role of the duodenum in vitamin D3 absorption in man.

Two different radioisotopic forms of vitamin D3, dissolved in a micellar solution, were infused separately and simultaneously into the duodenum and jejunum of healthy adult male volunteers. Net apparent absorption of each isotope was calculated by measuring the portion excreted in a 7-day stool collection. Mean apparent absorption of the vitamin D3 isotope, infused into the duodenum, was 77%, as compared with 65% for the vitamin D3 isotope infused into the jejunum, 60 cm distal. This small difference is thought to be due simply to the extra length of small intestine available for absorption of the vitamin D3 infused into the duodenum. These results suggest that the duodenum does not have unique efficiency for vitamin D absorption, as compared to the remainder of the small intestine.

Ascites in liver disease; mechanisms and therapeutic control.

The formation of ascites in any patient having liver disease is due to multiple factors. These factors vary in individual importance from case to case and thereby determine in part the wise choice of therapeutic measures to be employed for controlling a given ascitic collection.SummaryThe formation of ascites in any patient having liver disease is due to multiple factors. These factors vary in individual importance from case to case and thereby determine in part the wise choice of therapeutic measures to be employed for controlling a given ascitic collection.The various mechanisms causing ascites and the various principles of therapeutic attack have been discussed briefly.