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

In 39 normal pig pyeloureters, pelvic pressure was measured at the following perfusion rates: 0, 2, 4, 6, 8, 10 and 20 ml./min. The mean pelvic pressure increased from 7.09 to 21.53 cm. H2O. This increase showed 4 different phases. The first was a low pressure phase between 0 to 2 ml./min. where transport took place by peristalsis. The second was a high pressure phase between 2 and 4 ml./min. where the peristalsis opposed the passive interperistaltic filling of ureter. In the third phase, between 4 and 6 ml./min., a decreasing pressure increment was seen, probably caused by leakage through the contraction ring. In the fourth phase, between 6 and 20 ml./min., the pressure was proportional to the flow rate and ureter functioned hydrodynamically as a tube. The measurements were performed bilaterally in 19 animals. Fourteen animals showed a difference either in baseline pressure or in mean perfusion pressure between the 2 sides; in effect, no coherence in pressure exists between the pyeloureters in the individual pig. Ninety-five per cent confidence limits of the pelvic pressure were calculated at the different flow rates. The limits of the baseline pressure were 1.43 and 12.75 cm. H2O, respectively. During perfusion the upper limit of normal pressures increased markedly in the flow range 0 to 4 ml./min. being 25.46 cm. H2O at 4 ml./min. A further increase in flow rate caused only a modest increase in the upper limit. It is concluded that a comprehensive study of the pressure flow relationship provides new information concerning fluid transport in the upper urinary tract.
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PMID:Hydrodynamics of the normal multicalyceal pyeloureter in pigs: the pelvic pressure response to increasing flow rates, its normal ranges and intraindividual variations. 398 35

These experiments were designed to evaluate the hypothesis that K+ deficiency may be associated with decreased delivery of urea to the renal papillary collecting duct and/or decreased reabsorption of urea from the papillary collecting duct. Either of these factors would result in diminished capacity for urea recycling and might explain the mechanism of the urinary concentrating defect that is observed in K+ depletion. Munich-Wistar rats were fed 25 ml of water and 12 g of normal (CON) or K+-deficient (KD) diet each day for 21 days. Papillary collecting duct samples were obtained by micropuncture through the intact ureter. Fractional delivery of H2O to the base and tip of the papillary collecting duct was increased in KD as compared to CON rats (1.50 +/- 0.30% in KD vs 0.72 +/- 0.09% in CON at the base, P less than 0.01; and 0.55 +/- 0.08% in KD vs 0.30 +/- 0.05% in CON at the tip, P less than 0.01). However, fractional delivery of urea to the base and tip of the papillary collecting duct was not different between KD and CON rats (26.9 +/- 5.6% in KD vs 21.4 +/- 3.3% in CON at the base, P greater than 0.05; and 12.4 +/- 1.5% in KD vs 10.4 +/- 1.4% in CON at the tip, P greater than 0.05). Furthermore, reabsorption of water or urea between the base and tip of the papillary collecting duct was not decreased in KD as compared to CON rats (water reabsorption was 57.8 +/- 4.4% in KD and 55.9 +/- 5.11% in CON and urea reabsorption was 45.0 +/- 6.5% in KD and 45.9 +/- 5.4% in CON, P greater than 0.05). These results demonstrate that water reabsorption, but not urea reabsorption, is impaired in renal tubules proximal to the accessible papillary collecting duct in hydropenic rats.
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PMID:Urea reabsorption along the papillary collecting duct in potassium-deficient rats. 399 1

Muzolimine, a new diuretic, is known to act by inhibiting Na transport along the ascending limb of Henle's loop. Because of its ineffectiveness when perfused into the lumen, and as a result of experiments on frog skin, it is believed that muzolimine acts from the serosal cell side, unlike all other diuretics. We decided to assess the site of action of muzolimine (mucosa versus serosa) by experiments on rats. The animals were anesthetized, both ureters cannulated, and a hydronephrosis established in the left kidney by applying a counterpressure to the ureter, slowly and progressively increased up to 60 cm H2O in 3 minutes and kept stable for 20 minutes. Then either muzolimine 1.2 mg, or furosemide 4 mg, was injected i.v. together with 131I-Hypaque as a glomerular marker. Three minutes later the hydronephrosis was released in the left kidney by cutting the catheter, and urine collections were started simultaneously in both kidneys into 25 microliter glass capillaries, that were filled in continuous sequence and numbered progressively. In each urine sample from each glass capillary Na and 131I-Hypaque were measured. In 5 animals receiving furosemide, UNa rose in the left post-obstructed kidney and reached a plateau level by the 3rd to 5th sample. The rise in Na concentration, indicating delivery of urine whose Na reabsorption had been inhibited along the loop of Henle paralleled that in 131I-Hypaque, indicating that the diuretic and the glomerular marker had reached Henle's loop simultaneously, following filtration after the hydronephrosis had been discontinued.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Demonstration of action of muzolimine on the serosal side of Henle's loop cells. 400 94

Electron microscopic studies on the dynamics of changes in the epithelial cells and some elements of the intestinal mucosal lamina propria were performed on rats after bilateral high ureter ligation. Simultaneously, they were referred to blood serum biochemical and electrolyte disturbances. The ultrastructural changes indicate that as early as in the initial period of acute uraemia water-electrolyte disturbances become evident, which are still increasing. In the later period cell organelles alter and bacterial infection sets in. Ultrastructural abnormalities of the intestinal mucous membrane are increasing proportionally to biochemical and electrolyte disturbances of the blood serum.
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PMID:Ultrastructure of the epithelial cells of the small intestinal villi, the surface epithelium of the large intestinal mucosa and some elements of the intestinal mucosal lamina propria in rats with acute uraemia. 402 63

1. The capacity of adaptation of toads (Bufo bufo) to environments of high salinity was studied and the relative importance of skin, kidney and urinary bladder in controlling the balance of water and salt was assessed.2. Toads were kept in NaCl solutions of 20, 50, 110, 150 and 220 mM and studied in their fourth week of adaptation. A group of animals considered as ;control' was kept in wet soil with free access to water. Plasma, ureter urine, and bladder and colon contents were analysed for sodium, potassium, chloride and osmolality, and total body sodium and water were determined. Absorption of water and (22)Na through the skin, and water flow and sodium excretion through the ureter, of intact animals was studied. Hydrosmotic water transport through the isolated urinary bladder of ;control' and adapted animals was determined. The effects of pitressin and aldosterone on the water and sodium balance are described.3. The survival rates of toads kept in saline concentrations up to 150 mM were identical to that of ;control' animals, but half of the animals kept in 220 mM died within 4 weeks.4. There is a linear correlation between the sodium concentrations and osmolality of plasma and of the external media.5. The sodium concentration in colon contents rose with rising external concentrations, up to values higher than the values in plasma.6. Sodium concentrations and osmolalities of ureter and bladder urine increased in adapted animals, the values for bladder urine becoming much higher than those for ureter urine in animals adapted to 110, 150 and 220 mM.7. Total body water, as a percentage of total weight was kept within very narrow limits, although the total body sodium increased with adaptation.8. Absorption of water through the skin for the same osmotic gradients was smaller in adapted than in ;control' animals.9. The ureteral output of water of toads adapted to 110 and 150 mM-NaCl was larger than the water absorption through the skin.10. Skin absorption of sodium was lower in animals adapted to concentrated saline solutions than in ;control' animals.11. Sodium output by the ureter was identical to skin absorption in ;control' animals adapted to 20, 50 and 110 mM-NaCl but was higher in animals adapted to 150 mM-NaCl.12. Aldosterone increased the absorption of sodium in ;control' and adapted toads, but at all dose levels absorption by control was greater than by adapted animals.13. The stimulation of water absorption by vasopressin in vivo or in isolated bladders was not modified in animals adapted to high salinities.
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PMID:Salt adaptation in Bufo bufo. 463 11

1. Acute experiments were carried out on anaesthetized dogs during metabolic alkalosis produced by I.V. administration of NaHCO(3). Partial constriction of one ureter led to a significant rise in the HCO(3) (-) threshold, beyond the simultaneous value for the other kidney. The magnitude of the increase was not correlated with the reduction of glomerular filtration.2. Stop-flow analysis, following complete unilateral obstruction of urine flow, demonstrated proximal as well as distal tubular reabsorption of bicarbonate. At any given plasma P(co2) the detailed configuration of the concentration changes which developed depended on (a) the presence and concentration of mannitol, (b) the duration of urinary stasis, and (c) the plasma concentration of HCO(3) (-).3. If a solution containing 15% (w/v) mannitol was infused I.V., the HCO(3) (-) concentration in free flow urine was lower than in plasma, and it fell further during arrest of flow in the entire column of trapped fluid. If less mannitol was infused, or none at all, interruption of urine flow led to a striking increase of HCO(3) (-) concentration in the distal portion of the occluded column, and to a fall in the fluid arrested in the proximal segments.4. It was demonstrated that the HCO(3) (-) concentration attained after 2(1/2), 6, or 15 min of urinary stasis at any point in the trapped fluid column was due to the combined effects of water reabsorption and HCO(3) (-) reabsorption which proceeded independently, and with a different time course.5. If mannitol was administered the lowest urinary HCO(3) (-) concentration in the series moved progressively to a more distal location with increasing duration of urinary stasis. When HCO(3) (-) concentration peaks were present in distal fluid they were conspicuous only after short interruptions of urine flow; during extended stop-flow periods they became attenuated, or disappeared. If no mannitol was administered this did not occur.6. Provided the plasma level of HCO(3) (-) was sufficiently elevated, mannitol (15%, w/v) was administered, and the time available for reabsorption was lengthened by ureter obstruction, much larger concentration differences between plasma and trapped fluid developed than the largest that are ever found between the plasma and freely draining urine. The magnitude of the largest plasma-urine (P-U) concentration difference for HCO(3) (-) increased with intratubular ;contact time', and no limiting value was found.7. Potassium concentration in distal occluded fluid fell with prolonged duration of stasis. This was related to the slow and progressive diminution of distal HCO(3) (-) concentration. But if instead of bicarbonate a nonreabsorbable anion, such as phosphate, was the dominant distal anion, K(+) concentration in distal fractions remained high and rose further with time.
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PMID:Factors modifying renal tubular bicarbonate reabsorption in the dog. 563 89

The fine structure of the transitional epithelium of rat ureter has been studied in thin sections with the electron microscope, including some stained cytochemically to show nucleoside triphosphatase activity. The epithelium is three to four cells deep with cuboidal or columnar basal cells, intermediate cells, and superficial squamous cells. The basal cells are attached by half desmosomes, or attachment plates, on their basal membranes to a basement membrane which separates the epithelium from the lamina propria. Fine extracellular fibres, ca. 100 A in diameter, are to be found in the connective tissue layer immediately below the basement membrane of this epithelium. The plasma membranes of the basal and intermediate cells and the lateral and basal membranes of the squamous cells are deeply interdigitated, and nucleoside triphosphatase activity is associated with them. All the cells have a dense feltwork of tonofilaments which ramify throughout the cytoplasm. The existence of junctional complexes, comprising a zonula occludens, zonula adhaerens, and macula adhaerens or desmosome, between the lateral borders of the squamous cells is reported. It is suggested that this complex is the major obstacle to the free flow of water from the extracellular spaces into the hypertonic urine. The free luminal surface of the squamous cells and many cytoplasmic vesicles in these cells are bounded by an unusually thick plasma membrane. The three leaflets of this unit membrane are asymmetric, with the outer one about twice as thick as the innermost one. The vesicles and the plasma membrane maintain angular conformations which suggest the membrane to be unusually rigid. No nucleoside triphosphatase activity is associated with this membrane. Arguments are presented to support a suggestion that this thick plasma membrane is the morphological site of a passive permeability barrier to water flow across the cells, and that keratin may be included in the membrane structure. The possible origin of the thick plasma membrane in the Golgi complex is discussed. Bodies with heterogeneous contents, including characteristic hexagonally packed stacks of thick membranes, are described. It is suggested that these are "disposal units" for old or surplus thick membrane. A cell type is described, which forms only 0.1 to 0.5 per cent of the total cell population and contains bundles of tubular fibres or crystallites. Their origin and function are not known.
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PMID:The fine structure of the transitional epithelium of rat ureter. 585 20

Ureteral motility was studied in twenty-five sodium pentobarbital-anaesthetized sheep. Mean frequency of the peristaltic waves was 15 per min and the range was 11-19. Frequency was the same throughout the length of the ureter. Mean contraction pressure (cm H2O) was 40 in the upper ureter, 35 in the middle ureter and 31 in the lower ureter. Mean concentration time was 1 sec and range was 0.6-1.5. Mean relaxation time was 1.1 sec and range was 0.7-1.5. Diuresis induced by rapid intravenous administration of physiologic sodium chloride solution abolished the peristaltic activity.
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PMID:Ureteral motility in sheep. 616 12

Micropuncture of the rat renal papilla has disclosed an outward transepithelial gradient for NaCl at the bend of Henle's thin loop and an electrical potential difference, lumen positive, in the ascending thin limb. Substantial water extraction and urea secretion occur somewhere proximal to the bend, but direct evidence for transepithelial NaCl movement across the rat descending thin limb is lacking. In the hamster, water is extracted and urea secreted, but no NaCl gradient has been found, and in Psammomys there is indirect evidence for transepithelial entry of NaCl into the descending limb. Fluid is diluted in the ascending thin limb by reabsorption of NaCl. The lack of unequivocal evidence for active NaCl reabsorption has stimulated a search for alternative mechanisms of osmotic work in the inner medulla. The collecting duct plays a crucial role by its differential reabsorption of water (primarily in the cortex) and urea (exclusively in the inner medulla) but has not yet been shown to supply useful energy to the concentrating mechanism by active sodium reabsorption. Exposure of the papillary tip by ureteral excision impairs urinary osmolality. Ureteral peristalsis normally causes intermittent flow of fluid in the collecting duct, but abolition of intermittent flow by paralysis of the ureter does not decrease urinary osmolality. Superperfusion of the exposed papilla by a urea solution prevents the decline in osmolality but the amount of urea used greatly exceeds that available from the urine. Nevertheless, it is the intactness of the ureter that is somehow essential to maximum urinary concentration, perhaps by preventing loss of solute from the papilla rather than by supplying energy.
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PMID:The renal concentrating mechanism: micropuncture studies of the renal medulla. 634 Oct 87

We report about a case with simulated recurrent urolithiasis. The patient introduced foreign bodies (gypsum) into the bladder. Often the stones had to be removed from the bladder and the right refluxing ureter. The diagnosis of the foreign bodies was made after 2 years of malingering by X-ray diffraction (analysis: gypsum = CaSO4 . 2 H2O).
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PMID:[Recurring pseudo-urolithiasis]. 634 39


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