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Dive into the research topics where James A. Clifton is active.

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Featured researches published by James A. Clifton.


Gastroenterology | 1966

The small intestinal basic electrical rhythm (slow wave) frequency gradient in normal men and in patients with a variety of diseases

James Christensen; Harold P. Schedl; James A. Clifton

Summary We used an intraluminal salt-bridge electrode to record the small intestinal slow wave or basic electrical rhythm (BER) at many levels of the intestine. We found a descending BER frequency gradient in 12 normal subjects and in 13 patients with a variety of diseases. The descending gradient was stepwise in some normal subjects but linear in others. The data from normal subjects have bfeen pooled to establish a range of normal values. The mean frequency at the ligament of Treitz was 11.80 cycles per min (sd 0.32); at 225 to 239 cm below the incisor teeth it was 9.39 cycles per min (sd 0.18). Abnormal gradients were found in patients with hyperthyroidism and hypothyroidism, and in a patient with hyperparathyroidism, gastric hypersecretion, and diarrhea. The form and magnitude of this gradient may be important determinants of small intestinal motor function.


Journal of Clinical Investigation | 1968

Absorption of l-methionine from the human small intestine

Harold P. Schedl; Charles E. Pierce; Alan Rider; James A. Clifton

Absorption of L-methionine was measured in all parts of the human small intestine using transintestinal intubation and perfusion. In four normal subjects, adsorption was higher in the proximal than in the distal intestine. In two patients with nontropical sprue in relapse, there was a proximal zone of low absorption with higher absorption distally. In all parts of the small intestine, absorption showed rate-limiting kinetics as methionine concentration was increased. In normal subjects, the proximal K(m) (Michaelis constant) was more than 3 times higher than the distal, which suggests a difference in transport mechanisms between the two segments.


Gastroenterology | 1963

Cortisol absorption in man.

Harold P. Schedl; James A. Clifton; Duane D. Miller; George Nukes; Donald White

Summary Absorption of cortisol from Ringers solution in the normal human small gut was characterized by a distally decreasing gradient. This defines a membrane gradient in terms of this lipophilic-hydrophilic molecule. Glucose in the Ringers increased cortisol absorption uniformly throughout the small gut, but the gradient was maintained. It is hypothesized that this is a specific metabolic effect of high glucose concentration on mucosal cells throughout the small gut. It was concentration dependent, and was detected in the earliest measurements we could make, continued throughout glucose perfusion, and persisted for about 2 hours after glucose was stopped. Net water absorption from the gut was higher with glucose-Ringers than with Ringers and showed a gradient. The glucoseinduced increase in water absorption was chiefly in the upper small gut ( In patients with small gut malabsorption, cortisol and net water absorption rates were reduced, and in some cases their gradients were reversed.


Digestive Diseases and Sciences | 1964

THE EFFECTS OF GASTRIC FREEZING ON VITAMIN B12 ABSORPTION, ACID SECRETION, TISSUE MORPHOLOGY, AND SERUM ENZYMES.

Kenneth A. Hubel; Luke Faber; Thomas H. Kent; James A. Clifton; Edward E. Mason

SummaryIn controlled studies to determine the effect of gastric freezing in patients, the following was found:1.Microscopically the gastric mucosa showed mild degenerative changes with minimal reactive inflammation and foveolar hyperplasia. No necrosis was seen.2.Serum amylase, glutamic oxalacetic transaminase, and leucine aminopeptidase did not rise. This suggested that no appreciable injury to the liver or pancreas occurred.3.Vitamin B12 absorption did not decrease. The apparent increase in absorption that occurred was probably experimental artifact.4.Studies of gastric acid secretion using the maximum histamine and maximum insulin responses (maximum 30-min. output) suggested that injury to the mucosal nerve supply played a role in the reduction of acid secretion that follows gastric freezing.


Gastroenterology | 1968

Serum Concentrations and Renal Clearances of Amino Acids in Patients with Chronic Active Hepatitis

Edward L. Krawitt; James A. Clifton

Summary Serum concentrations and renal clearances of 17 amino acids were measured in 4 patients with chronic active hepatitis before and during glucocorticoid therapy. The most striking abnormality in initial serum amino acid levels was a 20-fold elevation of methionine in 2 girls, but tyrosine, histidine, lysine, and aspartic acid were also elevated. Methionine and tyrosine were at the upper limits of normal or slightly elevated in two men and histidine was elevated in one of them. During glucocorticoid treatment there was a generalized decrease in serum amino acid concentration in the 2 girls while the levels in the 1 man treated remained for the most part unchanged. Renal clearances for all amino acids studied were within normal limits.


Experimental Biology and Medicine | 1962

Polyvinylpyrrolidone-I131 as an Indicator of Net Intestinal Water Flux: Its Binding by Intestinal Mucus.∗

Harold P. Schedl; James A. Clifton

SummaryPolyvinylpyrrolidone labelled with I131 was compared with polyethylene glycol as an indicator of net water absorption in intestinal perfusion studies. Small losses of PVPI131 in normal subjects and large losses in patients with sprue could be explained by binding of the polymer to intestinal mucus. The role of this factor in fecal PVPI131 excretion is discussed. PVPI131 is not a useful indicator of net water flux in patients with sprue.We thank Abbott Laboratories for PVPI131 used in these studies and the Radiation Research Laboratories, State University of Iowa, for providing facilities for measurement of radioactivity.


Archives of Biochemistry and Biophysics | 1962

Steroid ester hydrolysis by the rat gut.

Erwin T. Janssen; Harold P. Schedl; James A. Clifton

Abstract This paper describes a general method for hydrolyzing steroid esters. Rat small intestine homogenized in saline was centrifuged. Steroid esters were incubated with the supernatant solution. Steroid mono- and diacetates, as well as a propionate, dienanthate, and phenylacetate were hydrolyzed. Esters of steroid hydroxyl groups at the 3α, 3β, 6β, 16α, sec-17β, and 21 positions were hydrolyzed. Steroids acylated at 11α, and tert-17α- and -β-hydroxyl groups were stable.


Experimental Biology and Medicine | 1959

A screening test for malabsorption syndromes.

A. W. Horsley; James A. Clifton; William E. Connor; Titus C. Evans

Summary Our studies indicate that measurement of changes in plasma optical density after a fatty meal is a simple and reliable screening test for patients with malabsorption syndromes. It is of value in following the course of these diseases and in evaluating response to therapy.


Nature | 1963

SOLUTE AND WATER ABSORPTION BY THE HUMAN SMALL INTESTINE.

Harold P. Schedl; James A. Clifton


Journal of Clinical Investigation | 1964

The Basic Electrical Rhythm of the Duodenum in Normal Human Subjects and in Patients with Thyroid Disease

James G. Christensen; Harold P. Schedl; James A. Clifton

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Charles E. Pierce

National Institutes of Health

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Duane D. Miller

University of Tennessee Health Science Center

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George Nokes

National Institutes of Health

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