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Biomedical subjects

W Kriz

Publications and source records attributed to W Kriz.

At least 145 records · Page 8Linked 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.

Animals↗
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.

Animals↗
PubMed1975

The ultrastructure of the thin loop limbs of the mouse kidney.

The thin limbs of the loops of Henle in the mouse kidney have been investigated by conventional electron microscopy. Resulting from light microscopic investigations, a distinction in the epithelia of short and long loops can be demonstrated. Ultrastructurally, the thin limbs (descending) of short loops are composed of a uniformly thin and simple epithelium. In contrast, long loops (thin descending and ascending) are composed of three different epithelial types which are representative of a distinctly more complex epithelial system. Two epithelial types were observed in the thin descending limbs of long loops and the third type was observed in the ascending thin limbs. Based upon these findings it is suggested that the thin descending limbs of short and long loops of Henle in the mouse kidney cannot perform the same functions in the renal concentrating mechanism.

Animals↗