Larry W. Welling

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A morphometric technique is used to estimate the absolute and relative surface areas of the brush border microvilli and cell walls bordering lateral intercellular spaces. In isolated, perfused proximal tubule from rabbit, the luminal and lateral surfaces are equal in area. For proximal convoluted tubules (PCT) each surface is 4.1 +/- 0.3 mu2/mu3 of(More)
To study the physical properties of renal tubular basement membranes directly, the epithelial layer of single isolated perfused rabbit proximal convoluted, proximal straight, and cortical collecting tubules was removed with sodium desoxycholate. Tubular segments were perfused using micropipets. The distal end of each segment was occluded in order to(More)
Isolated, lumen-collapsed S1, S2, and S3 proximal tubule segments from the rabbit were exposed acutely to media made hypotonic or hypertonic by adjusting the concentration of the impermeant solute raffinose. The result was a water flux into or out of the cells across their basolateral cell membranes and a consequent swelling or shrinking of the cells. From(More)
Isolated, lumen-collapsed, proximal and distally occluded segments of rabbit S1 and S2 proximal tubule were equilibrated in isotonic NaCl or isosmotic raffinose medium and then exposed acutely to hypotonic or hypertonic raffinose or NaCl solution. The result was a water flux per millimeter tubule length, JVo, across the basolateral cell membranes and a(More)
In electron micrographs of proximal convoluted (PCT) and proximal straight tubules (PST), epithelial height was divided into five zones of equal thickness. Morphometric techniques were used to calculate surface area of cell wall bordering intercellular channels in each zone. Surface concentration of total lateral cell surface is 3.85 mu2/mu3 of PCT and 2.90(More)
We examined the properties of basolateral cell membranes in "immature" and "mature" proximal tubules and evaluated the possibility that changes in those membranes might contribute to the reported maturation of tubule function. Proximal convoluted tubules were dissected in connection with superficial glomeruli, crimped at both ends, and induced to swell by(More)
We have evaluated the functional and morphological changes that occur in juxtamedullary proximal convoluted tubules before and after the completion of nephrogenesis at approximately 3 wk of age. Tubules were dissected in connection with glomeruli in the deep juxtamedullary zone, crimped at both ends, and induced to swell in isotonic medium by sequential(More)
Intracellular calcium ([Ca2+]i) and hydrogen ion concentrations (pHi) are important regulators of cell function. Those ions also may interact and it is important, therefore, to measure their concentrations simultaneously. In the present studies we used a system developed for that purpose, a fluorescent emission ratio technique for simultaneous analysis of(More)
The interrelationships between changes in intracellular calcium concentration ([Ca2+]i) and intracellular pH in Madin-Darby canine kidney cells and kidney glomerular epithelial cells exposed to various stimuli were analyzed simultaneously using a new design of a fluorescence video microscope. Cells were double labeled with indo 1 and SNARF 1 dyes and were(More)