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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was designed to evaluate whether a microfibrillary collagen hemostatic agent (Avitene) would cause retroperitoneal fibrosis and ureteric obstruction when applied along the side of the ureter and left in situ for a period of 6 months. The contralateral side served as a control. Serial intravenous urograms were obtained and histopathologic studies were conducted to evaluate these effects. No evidence of significant retroperitoneal fibrosis or ureteric obstruction was found either on serial intravenous urograms or on histopathologic examination of the ureter after 6 months.
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PMID:An evaluation of the tendency of Avitene to produce periureteral fibrosis in the dog. 633 96

The origin and development of mouse kidney vasculature were examined in chorioallantoic grafts of early kidney rudiments and of experimentally induced explants of separated metanephric mesenchymes. Whole kidney rudiments developed into advanced stages, expressed the segment-specific antigenic markers of tubules and the polyanionic coat of the glomeruli. In contrast to development in vitro, these grafts regularly showed glomeruli with an endothelial component and a basement membrane expressing type IV collagen and laminin. The glomerular endothelial cells in these grafts were shown to carry the nuclear structure of the host. This confirms the outside origin of these cells and the true hybrid nature of the glomeruli. When in vitro induced mesenchymes were grafted on chorioallantoic membranes, abundant vascular invasion was regularly found but properly vascularized glomeruli were exceptional. Uninduced, similarly grafted mesenchymal explants remained avascular as did the undifferentiated portions of partially induced mesenchymal blastemas. It is concluded that the stimulation of the host endothelial cells to invade into the differentiating mesenchyme requires the morphogenetic tissue interaction between the ureter bud and the mesenchyme. The induced metanephric cells presumably start to produce chemoattractants for endothelial cells at an early stage of differentiation. Kidney development thus seems to require an orderly, synchronized development of the three cell lineages: the branching ureter, the induced, tubule-forming mesenchyme, and the invading endothelial cells of outside origin.
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PMID:Differentiation and vascularization of the metanephric kidney grafted on the chorioallantoic membrane. 633

The use of stemmed patches and tubes from the seromuscular layer of the colon wall to replace part of the ureter has proven unreliable because of complications such as urinary leakage and invagination, fibrosis, bone formation, shrinkage and disappearance of the intestinal wall due to ischemia and necrosis, causing hydronephrosis and pyelonephritis. The use of tubes and patches of tanned and untanned collagen, implanted in order to study the ingrowth of urothelium and possibly muscle cells, resulted in fibrosis, bone formation, rejection of the material and, in the case of the tubes, complete obstruction with hydronephrosis and destruction of the kidney.
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PMID:Ureter replacement by collagen and seromuscular parts of the large bowel in dogs. 647 2

Upper excretory pathway musculature was studied by electron microscopy, both at the level of the obstruction and proximally. Two types of lesion were investigated: pyelo-ureteral junction anomalies and primary obstructive mega-ureter. Two types of muscle cell are recognized in the excretory pathway walls, typical and atypical cells, the latter being considered as possessing pace-maker activity and constituting almost total population of muscles of calices and pelvis. However, they were few in number in the pyelo-ureteral region and were practically absent from the ureter. Various conclusions can be drawn from the findings in this study. Both typical and atypical cells are modified in the obstructed upper excretory pathways. Ultrastructural appearances of lesions are identical at the site of an proximal to the obstruction. Modifications in these cells were: a rich sarcoplasmic reticulum, an increase in number of mitochondria and glycogen particles, disorganized distribution of contractile or cytoskeletal filaments, altered contact zones between contiguous smooth muscle cells, increased richness of granular endoplasmic reticulum and excessive development of the Golgi apparatus. More chronic lesions show enhanced fibrosis with reduced muscle contractility, the fibrosis affecting mainly elastic fibers in young patients and collagen fibers in more elderly subjects. The development of fibrosis may be due to changes in the granular endoplasmic reticulum and the Golgi apparatus. From the practical point of view, increase in fibrosis with duration of course of obstruction is an argument for as early as possible surgical intervention.
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PMID:[Ultrastructural modifications of the tunica muscularis in congenital obstruction of the upper urinary tract. Physiopathological interpretations and anatomo-clinical correlations]. 649 59

A series of experiments have been carried out in-vitro in order to assess the possibility of using a collagen membrane in the repair of various sections of the urinary tract following operative surgery such as the removal of a stone from the ureter. The collagen film has been tested for its compatability with urine, its ability to prevent leakage of fluid in a simulated wound in-vitro and for its ability to withstand any degradative effect of liver and kidney homogenates. The material was not significantly degraded by either urine or by tissue homogenates and was able to prevent leakage of fluid under the experimental conditions employed. Although some slight build-up of calcium and some trace elements took place after incubation in urine over a six-day period this was not significant. On the basis of the results obtained it has been decided to proceed to in-vivo trials on rabbits using the collagen membrane. The possibility of using such a material in partial nephrectomy operations is discussed.
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PMID:Preliminary development of a collagen membrane for use in urological surgery. 652 51

Chronic pyelonephritis was induced in young adult cats by the intravenous injection of a human or a feline strain of Escherichia coli after ligation of one ureter for 24 or 48 h. In the 3 cats infected with the feline strain, scarred kidneys from the obstructed side were removed at necropsy 3, 4 and 5 months later. Collagen was extracted from pyelonephritic and normal kidney tissue with dilute acetic acid and limited proteolysis with pepsin. Scarred kidneys gave higher yields of both acid-soluble collagen (normal = 0.57 +/- 0.12 mg per g tissue; scarred = 0.88 +/- 0.10 mg per g tissue) and pepsin-solubilized collagen (normal = 9.69 +/- 1.79 mg per g tissue; scarred = 20.02 +/- 2.84 mg per g tissue). There was no significant increase in the collagen yield from the kidneys of the 2 cats in which mild focal lesions were found 14 and 16 months after infection with the human strain of E. coli. Pepsin released collagens were separated by fractional salt precipitation and identified by agarose gel chromatography and polyacrylamide gel electrophoresis. Normal kidney was shown to contain collagen of Types I, IV and V (AB). The Type IV collagen extracted consisted of a mixture of 4 major pepsin-resistant chains of apparent molecular weights of 150 000, 115 000, 85 000 and 60 000. The collagen extracted from scarred kidneys was predominantly Type I, only trace amounts of Type IV and V components being present. These findings suggest that basement membrane collagens of the kidney are selectively degraded during the atrophy and scarring of chronic feline pyelonephritis and are preferentially replaced by interstitial Type I collagen.
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PMID:Experimental pyelonephritis in the cat: 3. Collagen alterations in renal fibrosis. 684 96

A method for initiating rapidly growing cultures of normal human transitional cells from ureter and embryonic bladder specimens has been developed and quantified. A new microdissection technique was used to nonenzymatically separate the urothelium. The use of enriched medium containing 10 micrograms/ml insulin, 5 micrograms/ml transferrin, and 1 microgram/ml hydrocortisone resulted in improved growth. The use of thin collagen gel substrates (0.6 ml/60 mm petri dish) resulted in 97% attachment of explants compared to 77% attachment on plastic. Explants grown on thicker collagen (2 ml/60 mm petri dish) showed, in addition to better attachment, enhanced growth of cells as determined both by measurements of colony size and cell density. Cultures of transitional cells that were initiated using explants could be passed three to five times using 0.1% EDTA for dispersion. Autoradiography of [3H]thymidine-labeled cells showed an initial phase of rapid cell division in primary explant cultures and restimulation of cell division in passaged cultures. Transmission electron microscopy showed that the cells growing out from the explants were continuous with the stratified urothelium maintained in the original explant. Stratification of transitional cells occurred in cultures of both ureter and embryonic bladder cells. Surface cells were joined near their apices by junctional complexes. Desmosomes and Golgi vesicles were present in all cells. Passage in culture did not alter the morphological characteristics of cells.
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PMID:Growth and characterization of normal human urothelium in vitro. 685 34

Conversion of the nephrogenic mesenchyme into epithelial tubules requires an inductive stimulus from the ureter bud. Here we show with immunofluorescence techniques that the undifferentiated mesenchyme before induction expresses uniformly type I and type III collagens. Induction both in vivo and in vitro leads to a loss of these proteins and to the appearance of basement membrane components including type IV collagen. This change correlates both spatially and temporally with the determination of the mesenchyme and precedes and morphological events. During morphogenesis, type IV collagen concentrates at the borders of the developing tubular structures where, by electron microscopy, a thin, often discontinuous basal lamina was seen to cover the first pretubular cell aggregates. Subsequently, the differentiating tubules were surrounded by a well-developed basal lamina. No loss of the interstitial collagens was seen in the metanephric mesenchyme when brought into contact with noninducing tissues or when cultured alone. Similar observations were made with nonnephrogenic mesenchyme (salivary, lung) when exposed to various heterotypic tissues known to induce tubules in the nephrogenic mesenchyme. The sequential shift in the composition of the extracellular matrix from an interstitial, mesenchymal type to a differentiated, epithelial type is so far the first detectable response of the nephrogenic mesenchyme to the tubule-inducing signal.
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PMID:Shift in collagen type as an early response to induction of the metanephric mesenchyme. 725 52

The right ureters of eight dogs were divided and the end of the proximal segments were attached to a spring generating a constant tension force of 26 to 30 mm Hg. After 2 weeks, the segments had elongated by an average of 33%; one segment did not elongate because of a spring failure. Six of the seven elongated segments were viable. Microscopically, the segments revealed muscular hypertrophy, increased collagen and elastic tissue, and periureteral inflammation and edema. This study indicates that a dog ureter may be mechanically elongated and its tissue viability maintained by applying a constant tension external stretching force.
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PMID:Experimental ureteral lengthening in dogs. 741 15

The normal structure of the ureter of the rat is described and compared with the results of earlier work. Research on arteries left in situ stimulated morphological investigation of the ligated ureter proximally and distally to the ligature. As in ligated blood vessels, an increase in modified muscle cells with accompanying increase in connective tissue (particularly proximally to the ligature) occurs in the ureter. In association with quantitative changes, qualitative changes in the formation of collagen and in the arrangement of fibrils were found, although not so marked as in arteries subjected to "load failure". During a comparison of the ureteric walls on either side of a ligature intracellular collagen was found. The results of earlier work on ligated ureters are discussed, together with the present findings. The reactions of ureteric and arterial walls subjected to similar "load failures" are compared. Qualitative changes in the intercellular substance are considered in connection with the findings in cases of pathological processes in the walls of blood vessels. Several possibilities are suggested with regard to the interpretation of the intracellular collagen.
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PMID:An investigation into the fine structure of the ligated rat ureter. 743 34


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