John P. Hayslett

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Recent studies have demonstrated that active chloride secretion in mammalian colon and other epithelia, is dependent on the induction of an increase of apical chloride conductance. Since the physical characteristics of apical chloride channels in man have not been elucidated, patch clamp analysis of human colon cells (HT29), in culture, was performed, after(More)
To characterize and contrast the active potassium absorptive and secretory processes present in the rat colon, unidirectional 42K fluxes were performed under short-circuit conditions across isolated distal (D) and proximal (P) colonic mucosa of control rats and animals with hyperaldosteronism due to sodium depletion (aldosterone group). In the control D(More)
To determine the effect of corticosteroids on active transport processes, unidirectional fluxes of 22Na, 36Cl, and 42K were measured under short-circuit conditions across isolated stripped distal colonic mucosa of the rat in control, secondary hyperaldosterone, and dexamethasone-treated animals. In controls net sodium and chloride fluxes (JNanet and JClnet)(More)
As the population of nephrons diminishes, while the dietary intake and/or endogenous production of water and solutes is unchanged, there is a proportional increase in the excretion of water and solute by individual residual nephrons. This adaptive change, which preserves zero net balance in the early phase of renal insufficiency, involves a reduction in the(More)
The prognostic markers in 87 consecutive patients with lupus nephritis who underwent renal biopsy are reported for five clinically relevant long-term outcomes--renal insufficiency, renal failure, death due to renal systemic lupus erythematosus, death due to non-renal SLE and death due to SLE, both renal and non-renal. We have demonstrated that a number of(More)
The functional correlates of compensatory renal hypertrophy were studied by micropuncture techniques in rats after the removal of one kidney. The glomerular filtration rate increased to roughly the same extent in the whole kidney and in individual surface nephrons, resulting in a greater amount of sodium delivered to the tubules for reabsorption. The(More)
UNLABELLED The model of sodium and chloride transport proposed for the colon is based on studies performed in the distal segment and tacitly assumes that ion transport is similar throughout the colon. In rat distal colon, neutral sodium-chloride absorption accounts for the major fraction of overall sodium absorption and aldosterone stimulates electrogenic,(More)
Dietary sodium depletion with elevated aldosterone levels induces electrogenic, amiloride-sensitive sodium absorption and inhibits electroneutral sodium chloride absorption in the rat distal colon. To assess the role of aldosterone in the production of these changes, unidirectional 22Na and 36Cl fluxes were performed under voltage clamp conditions across(More)
Adrenalectomized rats were maintained on physiologic replacement doses of aldosterone or dexamethasone for 24 h after adrenalectomy. Net cation movement and transmural potential difference were determined during in vivo perfusion of the colon. Adrenalectomy without replacement steroids resulted in marked reduction of sodium and water absorption, potassium(More)