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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)
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)
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)
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)
The fate of five herbicides (glyphosate, glufosinate-ammonium, phenmedipham, ethofumesate and metamitron) was studied in two Finnish sugar beet fields for 26 months. Soil types were sandy loam and clay. Two different herbicide-tolerant sugar beet cultivars and three different herbicide application schedules were used. Meteorological data were collected(More)
Isolated, perfused segments of late proximal straight tubule, descending thin limb of Henle, and ascending thick limb of Henle from the rabbit were studied before and after removal of the epithelium with sodium deoxycholate. The relationship between transmural hydrostatic pressure and outer tubule diameter was similar in paired intact tubules and basement(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)
Acquired renal cystic disease occurs in up to 80% of patients on chronic dialysis and is complicated by renal adenocarcinoma in about 6% of cases. This report suggests that acquired cystic kidneys weighing more than 150 g are six times more likely to contain carcinoma than are kidneys of smaller size. This relationship is true whether or not the large(More)
Models of cell shape in the rabbit S2 proximal renal tubule were derived from transmission electron micrographs and compared with scanning micrographs. Standard morphometric procedures were used to measure basolateral cell membrane surface density (SVt) relative to total epithelial volume in numerous zones of cell height. In the basal 20% region we also(More)