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B Kaissling

Publications and source records attributed to B Kaissling.

108 records · Page 6Linked to original sources
PubMed1978

Gap junctional coupling between the JGA and the glomerular tuft.

The juxtaglomerular apparatus (JGA) in the rabbit kidney was examined by transmission electron microscopy and by freeze fracturing. It was found, that the Goormaghtigh cells of the JGA are extensively coupled with the mesangial cells within the glomerular tuft by gap junctions. A broad band of gap junctions starting within the Goormaghtigh cells, traversing the transitional area at the root of the glomerular tuft and continuing along the mesangial cells has been revealed by freeze fracturing. No gap junctional connections to the macula densa cells have been found. In accordance with data from literature it may be stated that all smooth muscle derived cell groups at the vascular pole of the glomerulus (smooth muscle cells of the vas afferens and efferens, granular cells, Goormaghtigh cells, mesangial cells) are extensively coupled by gap junctions with each other. It is supposed that this cell system may act as a synchronized functional unit.

Animals↗
PubMed1977

The transition of the thick ascending limb of Henle's loop into the distal convoluted tubule in the nephron of the rat kidney.

Examination of serial semithin sections of rat kidney cortex and a subsequent electron microscopic study of selected areas revealed that the characteristic epithelium of the cortical part of the thick ascending limb of Henle extends for a varying distance beyond the macula densa. The transition from the relatively thin epithelium of the thick ascending limb at this site to the three--or even four--fold thicker epithelium of the convoluted part of the distal tubule is sharply defined and occurs without the interposition of an intermediate cell type. The position of the macula densa at the end but still clearly within the ascending limb of Henle's loop is functionally interpreted to guarantee the separation of the sensor point macula densa from disturbing influences which might arise from the secretory activity of the subsequent tubular portion.

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PubMed1975

The structural organization of the kidney of the desert rodent Psammomys obesus.

The architecture of the desert rodent Psammomys obesus has been studied by means of standard histologic procedures and by single nephron injections. As other rodent kidneys (rat, mouse), the Psammomys kidney consists of two types of nephrons, 66% short looped and 34% long looped nephrons. The cortex is composed of 4 to 5 layers of glomeruli, which lie closely put together, the glomeruli often touch each other. The superficial and the midcortical glomeruli give rise to short looped neophrons, the juxtamedullary to long looped nephrons. In the strongly developed medulla the inner stripe shows the most striking pattern. It consists of two distinct compartments, that of the giant vascular bundles and that of the interbundle regions. The giant vascular bundles consist of about 8 to 14% arterial vasa recta and 39 to 47% venous vasa recta; furthermore they include the thin descending limbs of the short loops of Henle which amount to 44 to 51% of the bundle structures. The tubules of the interbundle regions surround the bundles in a regular pattern. The inner zone is almost completely surrounded by the renal pelvis; the long broad papilla protrudes into the ureter. The thin descending limbs of short looped nephrons traverse the inner stripe inside the giant vascular bundles. Leaving the bundles they turn back within the inner stripe; their ascending limbs lie in the interbundle region. Both limbs of the long loops of Henle run in the interbundle region, together with the ascending limbs of the short loops and the collecting ducts. The long loops penetrate deeply the inner zone. Many bends are found near the tip of the papilla. The renal pelvis has a very specialized form. It penetrates the inner stripe with many complexely shaped extensions, which surround the giant vascular bundles. Large parts of the bundles with their thin walled structures are thus separated from the pelvic urine only by a single layer of cuboidal epithelium. The possible functional importance of the described specializations of the Psammomys kidney (giant vascular bundles, large inner zone, special shape of the renal pelvis) for the urine concentrating and urea recyclng mechanisms is discussed.

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PubMedDate not supplied

Anemia induces 5'-nucleotidase in fibroblasts of cortical labyrinth of rat kidney.

We recently observed a strong increase of 5'-nucleotidase in renal fibroblasts of rats that were anemic due to an immunity against erythropoietin. In order to test if the change of 5'-nucleotidase was related with anemia, we studied the distribution of the enzyme in irradiated rats treated with phenylhydrazine. The hematocrit of these rats decreased to 15% within 4 days and erythropoietin levels were more than 200 times over controls. After 7 days a histochemical study showed that the enzymatic activity and the immunoreactivity for 5'-nucleotidase was markedly enhanced in the fibroblasts of the cortical labyrinth. There was no modification of 5'-nucleotidase in other cell types of the kidney. The 5'-nucleotidase activity of renal fibroblasts in cell culture increased by 72% upon addition of 160 microM 5'-AMP to the culture medium for 8 days. We propose that anemia provokes an energy deficit in some structure in the cortical labyrinth. This might increase the concentration of 5'-AMP which would induce 5'-nucleotidase. An interesting consequence of these events would be an increased production of adenosine in the direct vicinity of some of its putative targets, the glomerular arterioles and the erythropoietin-producing cells.

5'-Nucleotidase↗
PubMedDate not supplied

Ultrastructural characterization of the connecting tubule and the different segments of the collecting duct system in the rabbit kidney.

In the rabbit kidney, the connecting tubule is a clearly delimited tubular portion interposed between the convoluted part of the distal tubule and the cortical collecting duct. Superficial nephrons have individual connecting tubules; the connecting tubules of deeper nephrons fuse together to form a so-called arcade. The collecting duct is subdivided, with respect to localization, into cortical, outer medullary and inner medullary collecting duct. Connecting tubule and collecting duct are lined by a total of three different cell types: the connecting tubule by the connecting tubule cell and the intercalated cell; the collecting duct by the principal cell and the intercalated cell present only in the cortical and outer medullary segment. The intercalated cell can have different manifestations ("gray", "black", and "light"). The principal cell undergoes gradual alterations from a very complicatedly organized prismatic cell (approximately 7.5 micron cellular height) in the cortical collecting duct to a very simply organized, high prismatic cell (approximately 75 micron cellular height) in the inner medullary collecting duct.

Animals↗
PubMedDate not supplied

Effects of inhibition of the vacuolar-type proton pump on nephron ultrastructure and acidification in the isolated perfused rat kidney.

The effects of bafilomycin, an inhibitor of the vacuolar-type (V-type) proton pump, on nephron ultrastructure and acidification were analyzed in isolated perfused kidneys from rats with acute metabolic acidosis. Acidic intracellular compartments were labelled with the weak base DAMP, that was subsequently visualized immunocytochemically. The distribution of the proton pump was studied by immunocytochemistry. Bafilomycin inhibited urinary acidification and caused pronounced ultrastructural changes in proximal tubule cells and B-type intercalated cells (B-IC cells). Immunoreactivity for DAMP showed that bafilomycin also inhibits intracellular acidification. The distribution of the proton pump was essentially unchanged by bafilomycin in A-IC cells. In B-IC cells, immunoreactivity accumulated over studded membrane material in the apical cytoplasm. The results indicate that the V-type proton pump is important both for intracellular and for urinary acidification.

Acids↗
PubMedDate not supplied

Effect of spironolactone treatment on the ultrastructure of cortical intercalated cells in the rat kidney.

The ultrastructure of intercalated cells in the rat renal cortex was investigated after 7 days of treatment with the mineralocorticoid inhibitor spironolactone. In untreated and treated animals, two subgroups of IC cells (A-IC and B-IC) could be recognized by electron microscopy, but a substantial fraction of IC cells that corresponded to neither A nor B forms, so-called NonA-NonB, was also found. After spironolactone treatment, qualitative and morphometric analyses showed a decrease in volume density of mitochondria, in cell cross-sectional area, and in boundary length of basolateral membranes in A-IC cells. Among the NonA-NonB-IC cells, some revealed especially abundant mitochondria. Although the frequency of NonA-NonB-IC cells did not change significantly, these mitochondria-rich cells appeared with increased frequency after spironolactone treatment. The ultrastructural changes in A-IC cells might reflect a direct effect of spironolactone on the A-IC cells. However, it is also conceivable that the changes are secondary to functional alterations induced in neighboring segment-specific cells by the experimental conditions.

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