Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is difficult to correlate structure with function in the kidney because of the extensive cell heterogeneity. Carbonic anhydrase (CA) is an enzyme that mediates renal acidification and is found predominantly in proximal tubule and collecting duct cells. We modified Hansson's method for histochemically identifying cellular CA activity on PLP-fixed rabbit kidney sections mounted on Millipore filters, and then removed the filters to perform peanut lectin and antibody labeling on the same sections. There was adequate preservation of morphology, and individual cells could be identified with CA activity in the cytosol and specific antibody or lectin labeling on the cell surfaces.
 ...
PMID:Novel method for performing carbonic anhydrase histochemistry and immunocytochemistry on cryosections. 137 37

We investigated the effects of endothelin-1 (ET-1) on Madin-Darby canine kidney (MDCK) cells, a cell line originating from the renal collecting duct. The activity of transepithelial transport was assessed as the rate of dome formation in monolayers grown on solid support. The pH value of the dome fluid (dome pH) was measured by means of pH-selective microelectrodes. Differentiation of monolayer cells was estimated as the peanut-lectin(PNA)-binding capacity of the apical membrane. Confluent monolayers were incubated for 12-72 h in serum-free medium at various concentrations of ET-1. Exposure to 1 nmol/l ET-1 reduced dome formation by a maximum of 41 +/- 8% (n = 4; P less than 0.02) after 24 h. ET-1 (10 nmol/l; 24 h) decreased dome pH from 7.52 +/- 0.02 (n = 53) to 7.36 +/- 0.03 (n = 51; P less than 0.02). Apical application of amiloride (1 mmol/l) reduced dome pH in both ET-1-treated and non-treated domes to essentially the same level, 7.25 +/- 0.03 (n = 19) and 7.23 +/- 0.03 (n = 17) respectively. ET-1 (10 nmol/l; 24 h) reduced PNA-binding capacity by 19 +/- 3% (n = 5; P less than 0.02). Moreover, ET-1 prevented the increase in PNA binding (+ 53 +/- 7%; n = 5) induced by 0.1 mumol/l aldosterone. We conclude that ET-1 inhibits transepithelial transport and PNA binding via inhibition of apical Na+/H+ exchange, thus antagonizing aldosterone action in MDCK cells.
 ...
PMID:Endothelin-1 blunts transepithelial transport and differentiation of Madin-Darby canine kidney cells. 161 24

The present study was designed to shed light on the extraordinary histochemical properties of the chromophobe cell renal carcinoma detected by Hale's colloidal iron reaction. Special emphasis was laid on the lectin histochemical analysis of cytoplasmic glycoconjugates. Binding of peanut agglutinin (PNA) and Erythrina cristagalli agglutinin (ECA) after enzymatic release of sialic acid and direct binding of Dolichos biflorus agglutinin (DBA) correlates well with the expression of binding sites for Sambucus nigra agglutinin (SNA) and Maackia amurensis agglutinin (MAA) revealing abundant sialylated carbohydrate moieties within the cytoplasm. This characteristic binding pattern differs considerably from the faint staining observed in the majority of other renal carcinomas, thus confirming that the chromophobe cell renal carcinoma is a distinct entity. However, the lectin binding pattern of renal oncocytoma obviously resembles that of chromophobe carcinoma indicating a close relationship between these renal tumors. Detailed analysis of adjacent renal parenchyma revealed a lectin binding pattern quite similar to that described in the chromophobe carcinomas exclusively in the intercalated cells lining the collecting duct. This finding suggests that the chromophobe cell renal carcinoma originates from the collecting duct epithelium. The detection of small complexes consisting of altered epithelia which display the morphological characteristics of chromophobe carcinoma and the histochemical properties of intercalated cells probably indicates the emergence of preneoplastic lesions preceding the development of chromophobe carcinoma. Even though further studies are clearly needed to elucidate the physiological role of the cellular glycoconjugates detected, the present results already provide valuable insight into the histogenesis and pathogenesis of the chromophobe cell renal carcinoma.
 ...
PMID:Sialylated glycoconjugates in chromophobe cell renal carcinoma compared with other renal cell tumors. Indication of its development from the collecting duct epithelium. 168 20

The usefulness of various segment and cell-type specific antibody, lectin and functional markers in the study of cystic renal lesions was evaluated. For this purpose, kidneys from recessive polycystic kidney disease (RPKD), thought to involve mainly the collecting ducts, and cystic kidneys of Meckel's syndrome (MS), which show dilation randomly along the nephron, were studied. The segment (and differentiation-stage)-specific anti-brush-border (specific for proximal tubules) antibodies stained morphologically normal proximal tubules, failed to react with cyst wall epithelium in RPKD, but readily stained some cysts in MS. Immunostaining for Tamm-Horsfall glycoprotein (distal tubules) similarly revealed normal tubular profiles, and also stained moderately dilated tubules, but not the large cysts in either disease type. Lectin markers of the distal tubules and collecting ducts (peanut agglutinin, Helix pomatia agglutinin and Dolichos biflorus agglutinin) reacted with both dilated tubules and with the cyst walls in RPKD and Meckel kidneys, suggesting that in RPKD, the dilations also occur in the distal nephron in addition to the collecting duct, and in MS in any part of the renal tubule. The cell type-specific functional marker of the collecting duct, anti-NaK-ATPase reactivity (found in principal cells) could be seen in RPKD but not in Meckel kidney cysts, suggesting a minor involvement of principal cells in MS. Consistent with this, only occasional carbonic anhydrase (found in intercalated cells) or band 3 (bicarbonate-chloride exchanger molecule of intercalated cells) of collecting ducts positive cells in the cysts could be seen, suggesting that intercalated cells are only sparsely seen in these lesions. The results show the usefulness of a panel of independent markers in studying the segment, cell-type and function-specific features of renal cystic lesions as a basis for their classification.
 ...
PMID:Polycystic disease of the kidney. Evaluation and classification based on nephron segment and cell-type specific markers. 169 Mar 15

The rabbit cortical collecting duct (CCD) consists of three major cell types: principal cells transport K+, beta-intercalated cells absorb Cl-, and alpha-intercalated cells secrete H+. We used functional and histological methods to assess axial distribution of these cell types along rabbit CCD. In perfused CCDs, lumen-to-bath Rb+ rate coefficient (an index of principal cell K+ transport) was not different in tubules from outer cortex (1 mm from renal surface) compared with those from inner cortex (2 mm from renal surface), suggesting that principal cell function is homogeneous along the CCD. In contrast, Cl- rate coefficient (a measure of beta-intercalated cell function) was twice as high in CCDs from outer compared with inner cortex, suggesting heterogeneity of beta-intercalated cells along the CCD. To further investigate these regional differences, we fixed and embedded kidneys and identified three cell types in CCD cross sections using carbonic anhydrase staining and peanut lectin binding. Comparing tubule cross sections from outer with those from inner cortex, we found no axial difference in the fraction of cells that were either principal cells (64%) or total (lectin binding and nonlectin binding) intercalated cells (36%). However, the lectin-binding intercalated cell subset was significantly increased in outer compared with inner cortex. We conclude that there is not heterogeneity of principal cells along the rabbit CCD; however, beta-cell number and function are increased in outer CCD. Collecting duct heterogeneity begins within the cortical segment.
 ...
PMID:Axial heterogeneity of rabbit cortical collecting duct. 184 61

Two major types of intercalated cells (IC) have been previously defined in rabbit collecting duct: alpha-cells have a basolateral band 3-like anion exchanger and secrete H+, whereas beta-cells bind peanut agglutinin (PNA) apically and are believed to secrete HCO3-. To further define IC types, we double-labeled kidney sections with anti-H(+) -ATPase antibodies and with either an anti-band 3 antibody or PNA. We found four patterns of staining: 1) IC with apical H(+)-ATPase and basal band 3, a configuration consistent with ongoing H+ secretion, which prevailed in the inner stripe of outer medulla (OMCDi); 2) diffuse H(+)-ATPase labeling across the cell and basal band 3, which was most numerous in the outer stripe of outer medulla (OMCDo); 3) IC with "bright" apical peanut lectin, diffuse H(+)-ATPase, and no band 3, which was abundant in the cortical collecting duct (CCD) and probably represents HCO3(-)-secreting cells; and 4) "hybrid" cells with various staining combinations (e.g., apical lectin binding and apical H(+)-ATPase), which although they are uncommon, were seen in the CCD. Consistent with this immunocytochemical finding of hybrid cells, cell-sorting studies on isolated CCD IC showed that 6-18% of PNA-positive cells also stained positively for band 3. We conclude that 1) band 3-positive IC in the OMCD vary axially. Most OMCDi IC are probably active proton secretors, whereas up to one-half of OMCDo IC may be latent H+ secretors. 2) The diffuse H(+)-ATPase pattern in putative beta-cells differs from comparable results in the rat and is not consistent with a "reversed" alpha-cell. HCO3- secretion by beta-cells may be driven by an H+ extrusion mechanism other than the alpha-cell pump re-sorted to the basolateral membrane. 3) The possibility of hybrid cells that might combine alpha- and beta-cell transport proteins suggests a mechanism for functional reversal of collecting duct IC polarity.
 ...
PMID:Colocalization of H(+)-ATPase and band 3 anion exchanger in rabbit collecting duct intercalated cells. 184 62

We have developed an in vitro model of human papillary collecting duct cells isolated from cadaver kidneys using methods similar to those we previously reported for the isolation of human proximal tubule cells. To date we have isolated papillary collecting duct cells from 100 normal human kidneys. Papillae were dissected and digested in Cellgro containing 400 U/ml collagenase. Cells were plated on fibronectin-coated culture flasks at a density of 10(4) live cells/ml in Cellgro supplemented with insulin and 10% fetal bovine serum. Confluent monolayers, which were able to withstand 600 mOSM for 8 h, were obtained within 10 to 15 d. Cells of primary isolates and first passages exhibited epithelial cell ultrastructure including cell junctions, microvilli, and cilia. A dark-brown reaction product was observed in these cells when stained by the immunoperoxidase method with peroxidase-labeled peanut lectin (Arachis hypogaea), which binds specifically to human distal tubule and collecting duct cells. These cells were negative for Factor-VIII (a marker for endothelial cells) and gamma-glutamyltransferase (a marker for proximal tubule cells). High activities of the glycolytic enzyme pyruvate kinase and arginine vasopressin-stimulated cAMP production in these cells are consistent with a distal nephron origin. The results indicate that human collecting duct cells can be isolated and cultured to provide an in vitro system to probe pathogenetic mechanisms of potential nephrotoxins.
 ...
PMID:Characterization of an in vitro system of human renal papillary collecting duct cells. 216 26

Cultured inner medullary collecting duct (IMCD) cells have been shown to secrete protons (H+) by two mechanisms: an N-ethylmaleimide- and dicyclohexyl-carbodiimide-sensitive electrogenic H(+)-ATPase or H+ pump, and an amiloride-sensitive, secondary active Na+H+ exchanger. These cells also express Cl-/HCO3- exchange and carbonic anhydrase activity in common with other renal epithelial cells involved in acid-base transport. Video fluorescence microscopy of individual cells using 2',7'-biscarboxyethyl-5(6)-carboxyfluorescein has demonstrated that adjacent-cultured IMCD cells show substantial functional intercellular heterogeneity. The development of H(+)-pumping activity is associated with high-baseline intracellular pH and peanut agglutinin (PNA) affinity, and loss of mitotic activity and of Na+/H+ exchange. The H(+)-pumping activity may be further enhanced by removal of fetal calf serum for 6-54 h or by selecting cells with high PNA affinity. IMCD cells in their most differentiated state form domes, which consistently showed the highest rates of H(+)-pumping activity, as well as high affinity for peanut lectin. When IMCD were plated at low density, domes developed relatively late (2-4 weeks), at which time cells located in the center of nests of contiguously growing cells were quiescent and showed H(+)-pumping activity but no Na+/H+ exchange. On the other hand, dense plating was associated with early development of domes (end of 1st week), at which time adjacent cells showed a high mitotic activity and Na+/H+ exchange, but no H(+)-pumping activity. We speculate that differentiation of IMCD cells results in the development of cell polarity.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Differentiation of proton-pumping activity in cultured renal inner medullary collecting duct cells. 216 49

Histological sections of neonatal rabbit kidney of various ages were analysed to study the ontogeny of the collecting duct system. In addition, the sections were incubated with fluorescent wheat germ (WGA) and peanut agglutinin (PNA) to investigate the terminal differentiation of collecting duct cells. With both lectins we found different binding behaviours in the three segments of the collecting duct anlagen, the ampullary bud, the ampullary neck and the collecting duct. During the observed steps in development the lectin-binding pattern in the collecting duct and the ampullary neck appeared unchanged. In the collecting duct most cells reacted with WGA and only a few with PNA, while in the ampullary neck all cells bound both WGA and PNA. In the ampullary bud, however, the lectin-binding pattern changed between unlabelled and completely labelled stages with both lectins. The results indicate that both intercalated and principal cells originate from a common precursor cell.
 ...
PMID:Successive lectin-binding changes within the collecting duct during post-natal development of the rabbit kidney. 224 17

Thirty kidney tumours of various histological type were histochemically investigated under the light microscope by means of the ABC-method. We used four biotinylated lectins which are known to bind also to normal renal tubular epithelial cells of different nephron segments. The nuclear grade, the histological growth pattern, the cell type and the histogenesis of the tumours were studied. The lectin of Lotus tetragonolobus bound to nine out of ten renal cell carcinomas with low nuclear grade, but in contrast no binding was seen in eight poorly differentiated ones. Four carcinomas mimicking collecting duct epithelium were also negative after treatment with this lectin, but showed strong staining after treatment with peanut agglutinin, Dolichos biflorus agglutinin and soybean agglutinin. Five oncocytomas showed a high affinity only for Dolichos biflorus agglutinin and only one case was positive with Lotus tetragonolobus agglutinin; three tubulo-papillary adenomas of the renal cortex without any oncocytes were negative with all of the lectins used. The value of lectin histochemistry in tumour pathology and its significance in routine pathological examination of kidney tumours are discussed.
 ...
PMID:Lectin histochemistry of kidney tumours and its pathomorphological relevance. 241 30


1 2 3 4 5 6 7 8 Next >>