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

The ultrastructure of the ureter in the nonhuman primate is described. In experimentally produced chronic pyelonephritis, the ureter shows extensive ultrastructural changes throughout the wall. The epithelium has cellular damage progressing from the basal cells to the superficial cells. There is an invasion of leukocytes into the intercellular spaces at all levels. The connective tissue layer seems thickened with an increase in active fibroblasts, leukocytes, collagen, and elastic fibers. There are various stages of damage in the smooth muscle layer and an abnormal increase of connective tissues between bundles and smooth muscle cells. The interdigitating nexuses seem stretched and altered. The changes are similar to those seen in ureteral obstruction and are assumed to be reparative.
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PMID:Chronic pyelonephritis. Electron microscopic study. III. The ureter. 11 82

Transmission electron microscopy was used to study the interface between the ureter and the mesonephric blastema. When the blastema is induced in a functional organ, numerous pseudopodial protrusions of the ureter and of the mesonephric cells lead to a close appostion between the two structures. The presence of squamous material, perhaps of a mucopolysaccharidic nature, with a network of collagen fibres is always found on this interface. These particular processes seem to play a role as a morphological basis for the phenomenon of induction. The importance of the extracellular matrix is discussed. Neither the occurrence of zones of close contact, reported by several authors, in other species, nor the fusion of membranes has ever been observed in Amphibia.
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PMID:[Ultrastructural features of ureter-mesenchyme interaction, during nephrogenic induction in Amphibia]. 41 11

The ureters in neonates and infants can be anatomically and functionally so severely compromised to warrant the term "dysplasia". The clinicopathologic criteria for this diagnosis are: 1) a variable degree of dilatation on the excretory urogram and/or cystogram. 2) poor or absent ureteral motility as observed on cine-fluoroscopy or at operation, 3) poor muscularization and decreased muscle/connective tissue ratio under light microscopy and 4) small and deformed muscle cells with nexuses that are markedly decreased or absent and intracellular organelles that are poorly defined under electron microscopy. Excessive collagen and ground substance are present throughout the ureter. Although these qualitative and quantitative structural abnormalities are non-specific and can occur as a result of prenatal obstruction and postnatal infection, their severity in early postnatal life and their frequent association with dysplastic kidneys suggest congenital dysplasia as their etiology.
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PMID:Ureteral structure and ultrastructure. Part V. The dysplastic ureter. 51 25

Histological, histochemical and electron microscopic techniques have been used to compare dilated and normal calibre segments of ureter and renal pelvis in cases of idiopathic hydronephrosis and primary obstructive megaureter. In both conditions a marked increase in collagen and elastic tissue occurs in the wall of the distended segment and this infiltration extends throughout the proximal dilated ureter and renal pelvis. Evidence is presented to show that in the dilated segment, smooth muscle cells are directly involved in the synthesis of connective tissue elements. These findings support the view that the primary anomaly in idiopathic hydronephrosis and primary obstructive megaureter can be attributed to a malfunction of smooth muscle cells in the ureter and renal pelvis. However, the possibility remains that the changes in smooth muscle are secondary and have been induced by obstruction and distension caused in these pathological conditions by unknown aetiological factors.
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PMID:Functional obstruction of the ureter and renal pelvis. A histological and electron microscopic study. 75 49

The mesonephretic blastema is formed by cells with a large nucleus, a dense cytoplasm containing few differentiated organelles. At the contact between the ureter and the mesonephretic blastema, the cells of the primary ureter have special characteristics: existence of an abundant "coat", numerous "villous processes" and a dense network of fibres of collagen.
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PMID:[The ultrastructure of the primary ureter and of the mesonephritic blastema before its differentiation in Rana dalmatina (Amphibia, Anuran)]. 80 74

Hoyer-Grosser's organs were studied in human digital biopsies. The fine structure of both the supplying arteries and collecting veins was found to be inconspicuous. Endothelial cells in the AV canals form a continuous layer. They are characterized by their rich content of specific organelles (Weibel-Palade bodies), especially in the venous segments. The epitheloid zone is composed of a variety of ramified smooth muscle cells (RSM). These appear either dense, when well provided with bundles of myofilaments, or clear, when including only a few myofilaments. The nuclei of dense RSM show condensed chromatin, while those of clear RSM are larger with loose chromatin texture. In addition, all transitional forms occur. Cell organelles are rarely seen within all types of RSM. The cytoplasmic processes reach other as well as endothelial cells. The preservation of our material did not allow observation of specialized membrane contacts in these zones. All RSM are invested with a regular basal lamina and well provided with surface vesicles. Profiles of free basal lamina material and faint collagen (argyrophil) fibers are seen in the wide intercellular spaces. RSM poor in myofilaments are interpreted to represent "epitheloid cells" of light microscopy. Their number constantly decreases from the arterial segment of the AV canal to the venous segment. Here the cytoplasmic processes of RSM become less pronounced and the wall of the anastomotic segment continuously changes to that of the collecting vein. Dense RSM rich in myofilaments are compared with pacemaker cells found inthe ureter. Both internal and external elastic membranes are absent in AV canals. A dense network of unmyelinated nerve fibers is found in the adventitial layer of the AV canal, especially in its arterial segment. The axons branch out from small dermal nerves which also contain two or three myelinated axons. The myelin sheaths terminate where the axons reach the adventitia of the AV canals. Axon varicosities filled with mitochondria are thought to be terminals of myelinated axons and are interpreted as receptory. Axon varicosities with synaptic-type vesicles are assumed to be terminals of sympathetic and para sympathetic fibers. All axon profiles are confined to the adventitial layer of the anastomotic segment.
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PMID:The fine structure of human digital arterio-venous anastomoses (Hoyer-Grosser's organs). 86 21

A quantitative histological study of the dilated ureter of childhood was performed on 26 ureters. The specimens were from 15 male and 11 female patients 10 days to 12 years old (mean age 2.0 years). A color image analysis system was used to examine and compare collagen and smooth muscle components of the muscularis layers to normal control ureters of similar age. In comparing primary obstructed (12) to primary refluxing (14) megaureters and control ureters (6), there was a statistically different collagen-to-smooth muscle ratio (p < 0.001) between the primary obstructed and primary refluxing megaureter groups. For patients with primary refluxing megaureter there was a 2-fold increase in the tissue matrix ratio of collagen-to-smooth muscle when compared to patients with primary obstructed megaureter. In the primary obstructed megaureters the amount of collagen and smooth muscle was not statistically different from controls (p > 0.01). The increased tissue matrix ratio of 2.0 +/- 0.35 (collagen-to-smooth muscle) in the refluxing megaureter group compared to 0.78 +/- 0.22 in the obstructed megaureter group and 0.52 +/- 0.12 in controls was found to be due not only to a marked increase in collagen but also a significant decrease in the smooth muscle component of the tissue. Primary obstructed and normal control ureters had similar quantitative amounts of smooth muscle with 60 +/- 5% and 61 +/- 6%, respectively, while refluxing megaureters had only 40 +/- 5% smooth muscle. The percentage collagen was 36 +/- 5 in the obstructed megaureter group and 30 +/- 5 in controls, with refluxing megaureters having 58 +/- 5% collagen on analysis. Our findings emphasize the significant differences in the structural components (collagen and smooth muscle) of the dilated ureter of childhood, and provide us with further insight into the pathological nature of these dilated ureters and their surgical repair.
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PMID:A quantitative histological analysis of the dilated ureter of childhood. 143 52

We retrospectively analyzed pre- and postoperative sonographic and medical records of 335 children who had surgical or endoscopic treatment at the ureterovesical junction, in order to determine normal and atypical sonographic appearances. Normal sonographic findings after ureteral reimplantation include thickening of the posterior bladder wall, pseudodiverticular sacculations, bladder asymmetry, and transitory hydroureteronephrosis. Short-term or persistent (lasting more than 1 month) hydroureteronephrosis, urinoma, hematoma, bladder lithiasis, and diverticula were abnormal findings, occurring in 17% of the patients. After partial ureteronephrectomies, visualization of the residual ureter on sonograms was not possible in cases without complications; in one patient, reflux of fluid dilated the residual ureter and made the ureter visible on sonograms. After endoscopic incisions, the masslike appearance of a collapsed ureterocele was observed. Submucosally injected Teflon always appeared as a curvilinear hyperechoic area with an acoustic shadow. Marked acute or persistent hydroureteronephrosis or ectopic intracavitary Teflon particles were observed in 2% of patients. Granuloma formation was considered likely in 5% of the patients when the area of injected Teflon material was longer than 12 mm on sonograms. Submucosally injected collagen appeared less echogenic than Teflon and showed no acoustic shadowing. The various normal sonographic appearances after treatment must be known in order to distinguish them from significant abnormalities. In patients with anatomic anomalies, such as short-term or persistent hydroureteronephrosis, urinoma, hematoma, and lithiasis, complementary uroradiologic examinations may be necessary to clarify the diagnosis.
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PMID:The ureterovesical junction in children: sonographic findings after surgical or endoscopic treatment. 154 3

Endoscopic subureteral injection has become an established alternative means for treating vesicoureteral reflux in select children. However, which injection material to use remains a controversy. Polytetrafluoroethylene (Teflon) has been injected in more than a thousand patients with few complications, although experimental and clinical studies have demonstrated migration of the injected particles into distant organs, such as the lungs and the brain, as well as local and metastatic granuloma formation. Therefore, we introduced, following experimental studies in the mini-pig model, glutaraldehyde cross-linked, highly purified bovine collagen for injection. Between June 1988 and October 1991, 97 refluxing ureters in 66 children were treated by endoscopic subureteral collagen injection. In 58.8% of the ureters reflux was cured after 1 and in 77.3% after 2 injections. Considering improvement to grades I and II reflux without further treatment as success, the success rate increased to 68.0% after 1 and to 89.7% after 2 injections. Mean followup was 18.5 months (range 3 to 39 months). After 2 failed injections the patients either returned to antibiotic long-term prophylaxis or the reflux was operatively corrected. The operative procedure was never compromised by the preceding injection. A direct correlation between deficient length of the submucosal tunnel of the intravesical ureter and the iatrogenic malposition of the collagen deposits, and the failures could be demonstrated. Granuloma formation at the site of injection was not found. The results of the histological investigation of the collagen deposits removed at open ureteral reimplantation for failures are reported. It could be demonstrated that endogenous fibroblasts invade the bovine collagen implant and that these cells show active production of new human collagen, types I and III, replacing the implant.
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PMID:Subureteral collagen injection for the endoscopic treatment of vesicoureteral reflux in children. Followup study of 97 treated ureters and histological analysis of collagen implants. 164 May 54

In vitro tissue culture techniques were employed to study the effects of bacterial endotoxins on the growth of normal epithelial cells from the human ureter (NHU). Primary cultures of NHU cells were initiated from explant outgrowth cultures of human ureteral tissue and cultured on collagen gel in F-12* medium containing 1% fetal calf serum (FCS). Optimal clonal growth of secondary cultures of NHU cells seeded at relatively low seeding cell densities, directly on plastic dishes, was achieved in F-12* medium containing bovine pituitary extract (0.5% BPE) and 0.05% BSA. Results indicated that insulin in the F-12* medium could be replaced by three orders of magnitude less IGF-1. Further clonal growth experiments demonstrated that PGE1 is growth stimulatory and can replace BPE as a growth factor requirement. This finding was in agreement with the fact that BPE growth requirement could be replaced by cholera toxin or dibutyryl cAMP. These results suggested that both BPE and cholera toxin operated by activation of a cAMP-dependent mitogenic pathway. Seven gram-negative bacterial lipopolysaccharides (LPS) and three gram-positive bacterial lipotechoic acids (LT) were tested for their effects on NHU clonal growth. Three out of the five LPS derived from Escherichia coli (strains 055:B5, 0128:B12, and 0127:B8), LPS from Klebsiella pneumoniae, and LPS from Pseudomonas aeruginosa all showed significant growth inhibitory effects at minimally effective doses ranging from 5 to 25 micrograms/ml. LPS derived from E. coli strain (0111:B4) had no growth effects at the highest concentration tested (100 micrograms/ml). In contrast, LT derived from Streptococcus pyogenes, S. faecalis, Staphylococcus aureas, and Bacillus subtilis all markedly enhanced clonal growth at concentrations ranging from 1 microgram/ml less than [LT] less than 50 micrograms/ml. LT from Strep. pyogenes was inhibitory to clonal growth at 100 micrograms/ml. The growth inhibitory effects of LPS were shown to be sensitive to the presence of hydrocortisone in the growth medium, indicating that LPS effects on growth are mediated via the arachidonic acid cascade. We speculate that these results indicate a link between the susceptibility of uroepithelial tissue to the pathogenic microflora seen in urinary tract diseases and the differential sensitivity of proliferation-competent uroepithelial cells to growth inhibition by LPS produced by gram-negative bacteria. However, further studies with uropathogenic serotypes will be necessary to corroborate this possibility. The growth-stimulating activity of LTs produced by gram-positive bacteria may be due to their ability to bind to cell-associated fibronectin and to activate the fibronectin receptor as part of ligand receptor-induced mitogenic transmembrane signalling pathway.
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PMID:Effects of growth factors, hormones, bacterial lipopolysaccharides, and lipotechoic acids on the clonal growth of normal ureteral epithelial cells in serum-free culture. 173 Jul 86


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