Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The first measurements of AVT-sensitive adenylate cyclase activity in specific segments of the nephron of the Australian arid-zone agamid lizard, Ctenophorus (=Amphibolurus) ornatus, are reported. All sections of the collecting-duct system of this lizard were found to be sensitive to AVT at a concentration of 1 x 10(-6) M. In addition, receptors to AVT were located in the thin-intermediate segment linking proximal and distal convoluted tubules. No significant response to AVT was detected in the glomeruli, in either proximal or distal convoluted tubules, or in the ureter. The physiological significance of these particular segments is discussed in terms of the action of AVT in stimulating water and salt reabsorption in the lizard kidney.
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PMID:Arginine vasotocin: locus of action along the nephron of the ornate dragon lizard, Ctenophorus ornatus. 881 98

Mechanical properties of ureters from rats with infravesical urinary outflow obstruction were studied in vitro. Urinary outflow obstruction was created by partial ligation of the urethra in female rats. After 10 days a marked hypertrophy of the urinary bladder and a dilatation of the ureters were observed. Proximal and distal segments of the ureters from these animals were isolated and mounted in a wire myograph for force registration. Comparisons were made with ureters from control rats. The ureters from the rats with urinary outflow obstruction exhibited a large increase in lumen diameter and an unchanged thickness of the muscle layer. These data suggest that the dilatation of the ureters is associated with growth of the smooth muscle in the wall. All ureter preparations were relaxed in normal physiological salt solution. When the extracellular K+ concentration was increased to 20 mM the dilated ureters became spontaneously active. At [K+] in the range 20-40 mM in the presence of noradrenaline (10(-5) M) all ureters exhibited high-frequency spontaneous contractions. The dilated ureters had a lower frequency of spontaneous contractions and a higher force. The results show a pronounced remodelling of the ureter wall following infravesical outlet obstruction. The structural changes were associated with alterations in the contraction pattern of the preparations, most probably reflecting changes in the excitation-contraction coupling of the growing cells.
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PMID:Contractile properties of ureters from rats with infravesical urinary outlet obstruction. 984 Mar 43

Green toads (Bufo viridis) were acclimated to either tap water, 230 mOsmol NaCl kg-1 H2O (saline), 500 mOsmol NaCl kg-1 H2O (high saline), or 500 mmol L-1 urea. Renal functions for each acclimation group were studied on conscious animals that had one ureter chronically catheterized. Reciprocal immersion of tap-water- and saline-acclimated toads in the opposite solution did not stress the animals osmotically, and plasma osmolality increased or decreased by no more than 15%. However, urine osmolality and ionic composition changed immediately and profoundly on exposure to the other solution. Exposure of tap-water-acclimated toads to saline decreased urine flow by 30%, whereas the reciprocal immersion led to an increase of 30%. Immersion of tap-water-acclimated toads in high saline led to immediate cessation of urine flow, whereas immersion of 500 NaCl- or urea-acclimated toads in tap water led to a large increase in urine flow, with an overshoot that lasted 10 h (as a result of either salt or urea diuresis). Urine flow then stabilized at a level 5-6 times higher than the value attained at high-salt environment. On immersion of 500 urea-acclimated toads in 500 NaCl, urine flow doubled, accompanied by a change in ion composition, without change in the osmolality. In all experimental conditions, plasma potassium concentration was maintained within a narrow range. The results show that the toad's kidneys contributed efficiently both to osmo- and ionoregulation in a wide range of ambient solutions.
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PMID:Renal response of euryhaline toad (Bufo viridis) to acute immersion in tap water, NaCl, or urea solutions. 1006 26

Coadministration of biphenyl and KHCO3 in the diet of male rats for 13 weeks produced urine crystals, which, by means of LC-MS/MS analyses, were determined to be composed of the potassium salt of 4-hydroxy-biphenyl-O-sulfate (4-HBPOSK). Biphenyl alone or biphenyl with KCl or NaHCO3 in the diet did not produce urine crystals. It was found that the higher concentration of potassium in the urine and the alkaline pH induced by feeding KHCO3 to rats resulted in the formation of urine crystals of 4-HBPOSK due to 4-HBPOSK solubility being lower in urine than in plasma. Urine crystals of 4-HBPOSK produced hyperplasia of the transitional epithelium of the ureter, ureteral obstruction, and hydronephrosis in the urinary tract.
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PMID:Mechanism of urinary tract crystal formation following biphenyl treatment. 1144 27

Urea transporter UT-B has been proposed to be the major urea transporter in erythrocytes and kidney-descending vasa recta. The mouse UT-B cDNA was isolated and encodes a 384-amino acid urea-transporting glycoprotein expressed in kidney, spleen, brain, ureter, and urinary bladder. The mouse UT-B gene was analyzed, and UT-B knockout mice were generated by targeted gene deletion of exons 3-6. The survival and growth of UT-B knockout mice were not different from wild-type littermates. Urea permeability was 45-fold lower in erythrocytes from knockout mice than from those in wild-type mice. Daily urine output was 1.5-fold greater in UT-B- deficient mice (p < 0.01), and urine osmolality (U(osm)) was lower (1532 +/- 71 versus 2056 +/- 83 mosM/kg H(2)O, mean +/- S.E., p < 0.001). After 24 h of water deprivation, U(osm) (in mosM/kg H(2)O) was 2403 +/- 38 in UT-B null mice and 3438 +/- 98 in wild-type mice (p < 0.001). Plasma urea concentration (P(urea)) was 30% higher, and urine urea concentration (U(urea)) was 35% lower in knockout mice than in wild-type mice, resulting in a much lower U(urea)/P(urea) ratio (61 +/- 5 versus 124 +/- 9, p < 0.001). Thus, the capacity to concentrate urea in the urine is more severely impaired than the capacity to concentrate other solutes. Together with data showing a disproportionate reduction in the concentration of urea compared with salt in homogenized renal inner medullas of UT-B null mice, these data define a novel "urea-selective" urinary concentrating defect in UT-B null mice. The UT-B null mice generated for these studies should also be useful in establishing the role of facilitated urea transport in extrarenal organs expressing UT-B.
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PMID:Urea-selective concentrating defect in transgenic mice lacking urea transporter UT-B. 1179 14

An ex vivo study was conducted in a porcine model to compare the tensile strength of tissue samples repaired by three different repair methods: (i) scaffold-enhanced light-activated albumin protein solder, (ii) scaffold-enhanced n-butyl-cyanoacrylate adhesive, and (iii) conventional sutures. Biodegradable polymer scaffolds of controlled porosity were fabricated with poly(L-lactic-co-glycolic acid) (PLGA) and salt particles using a solvent-casting and particulate-leaching technique. Repairs were conducted on seventeen different tissues including the carotid, femoral, splenic, coronary, and pulmonary arteries, aorta, small intestine, ureter, sciatic nerve, spleen, atrium, kidney, muscle, skin, lung, liver and pancreas. Acute breaking strengths were measured and the data were analyzed by Student's T-test. The resultant repairs using the scaffold-enhanced light-activated adhesive (Group I) were found to yield equivalent tensile strengths to conventional sutures (Group III), with significantly smaller mean standard deviations (8% vs. 25%). The cyanoacrylate-doped scaffold (Group II) repairs performed extremely well with tensile strengths approximately 30% higher for organ tissue and approximately 20% higher for vascular tissue than with the other two repair techniques evaluated in this study. The addition of the polymer scaffold assists in tissue alignment and reduces problems associated with adhesive runaway from the repair site. With appropriate packaging, scaffold-enhanced adhesives offer the potential for quick application in the field by less skilled professionals, paraprofessionals and bystanders in emergency situations--both military and civilian--outside a hospital or clinic setting.
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PMID:Scaffold-enhanced albumin and n-butyl-cyanoacrylate adhesives for tissue repair: ex vivo evaluation in a porcine model. 1272 12

Bioassays for the carcinogenicity of nitrilotriacetic acid, trisodium salt, monohydrate (Na3-NTA-H2O) were conducted at Stanford Research Institute (SRI), using Fischer 344 rats and at Litton Bionetics, Inc. (LBI), using both Fischer 344 rats, and B6C3F1 mice. Similar bioassays using rats and mice, were conducted at LBI on the free acid, nitrilotriacetic acid (NTA). Each chemical was mixed in respective diets and administered ad libitum. The Na3-NTA-H2O was tested in rats at SRI at 200, 2,000, and 20,000 ppm for a 24-month period. It was also tested in rats at LBI at 7,500 and 15,000 ppm and in mice at 2,500 and 5,000 ppm using 18-month feeding periods for both species. The NTA was tested in rats and mice at LBI at 7,500 and 15,000 ppm for the 18-month period. The numbers of animals used in tests at SRI were 24 of each sex for each dose group and for the controls; at LBI, 50 of each sex for each dose group and 20 of each sex for the controls. Since equimolar quantities of Na3-NTA-H2O and NTA were not used, given concentrations of Na3-NTA-H2O represented 30% less NTA than did equal concentrations of the free acid. Average weights attained by high-dose groups of rats and mice were consistently lower than those of control groups. Less difference was observed with the low-dose groups. Survival, however, was not decreased by the compounds administered, except in rats given 20,000 ppm Na3-NTA-H2O. Lesions of the urinary tract were found in most treated groups of both rats and mice. They were characterized, especially in the high-dose groups, by primary tumors of epithelial origin. These tumors were particularly significant since they were not found in the urinary tract of the control mice and only rarely occur spontaneously in the strains of animals on test. Lesions of the urinary tract were also characterized by hydronephrosis and/or nephritis in high-dose rats and by nephritis in both high- and low-dose mice. Statistical evidence of the carcinogenicity of Na3-NTA-H2O and NTA was provided by incidences of tumors at different sites in the urinary tract. For example, among animals given 20,000 ppm Na3-NTA-H2O at SRI, tumors of the kidney occurred in male (treated, 9/24; untreated, 0/24; P=0.001) and female (treated, 4/24; untreated, 0/24; P=0.054) rats; tumors of the ureter in male (treated, 8/24; untreated, 0/24; P=0.002) and female (treated, 6/24; untreated, 0/24; P=0.011) rats; and tumors of the bladder, in female rats (treated, 5/24; untreated, 0/22; P=0.031). Similarly, among animals given 15,000 ppm NTA at LBI, tumors of the bladder occurred in female rats (treated, 12/48; untreated, 0/18; P=0.014) and tumors of the kidney occurred in male mice (treated, 24/44; untreated, 0/20; P<0.001). Additional tests at LBI, using 15,000 and 7,500 ppm Na3-NTA-H2O and 7,500 ppm NTA in male and female rats, 15,000 ppm NTA in female mice, and 7,500 ppm NTA in male mice, also induced tumors of the urinary tract, but in numbers too low to be statistically significant. Metastatic tumors, appearing to have arisen from primary tumors of the urinary trac the urinary tract, were found in 5/24 male and 5/24 female rats given 20,000 ppm Na3-NTA-H2O at SRI and in one male rat given 15,000 ppm NTA at LBI; none were found in rats given lower doses or in mice. Thus, NTA and Na3-NTA-H2O were shown to be carcinogenic to the urinary tracts of both rats and mice at the higher doses tested. Lower doses, as delineated in this report, did not induce significant numbers of such lesions.
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PMID:Bioassays of nitrilotriacetic acid (NTA) and nitrilotriacetic acid, trisodium salt, monohydrate (Na3-NTA-H2O) for possible carcinogenicity. 1284 92

Glomerular filtration rate (GFR) is inversely and thus paradoxically related to dietary NaCl intake in rats and patients with early type 1 diabetes mellitus (DM). Enhanced sensitivity of proximal reabsorption to NaCl diet inducing secondary adaptations in GFR through actions of tubuloglomerular feedback causes this salt paradox. We studied the role of renal nerves for the salt paradox in rats with streptozotocin (STZ)-induced DM since a regulatory influence of renal nerves on proximal reabsorption is well established. The left kidney (LK) was denervated before induction of STZ-DM. Subsequently, the normal diet was continued or a low NaCl diet was initiated and 1 week later animals were prepared for clearance experiments under anesthesia including ureter catheterization to measure GFR for each kidney. In diabetic rats, the right innervated as well as the left denervated kidney showed higher values for GFR and kidney weight in animals on a low versus a normal NaCl diet indicating that the salt paradox occurs independent of renal innervation. In addition, evidence is provided that the renal nerves of non-diabetic rats do not contribute to renal Na(+) retention during dietary NaCl restriction but modulate renal hemodynamics and kidney weight under these conditions.
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PMID:The salt paradox of the early diabetic kidney is independent of renal innervation. 1461 Mar 39

Although ultrasonography is regarded as the gold standard in the diagnosis of obstructive nephropathy, dilatation is sometimes not observed by ultrasonography. We report upon a case of minimally dilated obstructive nephropathy due to an ureter stone in a kidney donor with volume depletion. A 54-year-old man was admitted due to anuria and abdominal pain of 2 days duration. Ten years previously, his right kidney was donated for transplantation, and one month before admission, he abstained from all food except water and salt, for 30 days for religious reasons. He had lost 8 kg of body weight. On admission, he had clinical signs of volume depletion, i.e., a dehydrated tongue and decreased skin turgor. Laboratory data confirmed severe renal failure, his blood urea nitrogen level was 107.3 mg/dL, and his serum creatinine 16.5 mg/dL. The plain X-ray was unremarkable and ultrasonography showed only minimal dilatation of the renal collecting system. On follow-up ultrasonography, performed on the 5th hospital day, the dilatation of the collecting system had slightly progressed and a small stone was found at ureter orifice by cystoscopy. Removal of stone initiated dramatic diuresis with a rapid return of renal function to normal by the third day.
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PMID:Minimally dilated obstructive nephropathy initially suspected as pre-renal azotemia in a kidney donor with volume depletion. 1471 34

Although the regulation of cyclooxygenase-2 (COX-2) expression in the kidney cortex has been extensively characterized, the physiological control mechanisms of COX-2 expression at the level of the kidney and at the level of the tubular cells are not well understood. Based on the current hypothesis that tubular salt transport might be a crucial regulator of COX-2 expression, this study aimed to determine the impact of salt delivery to the tubules (glomerular filtration) for the regulation of COX-2 in the kidney cortex in vivo. To this end, glomerular filtration of the right kidney was abrogated by the ligation of the right ureter of male Sprague-Dawley rats. After 1 wk of ligation, the animals were treated with subcutaneous infusions of furosemide (12 mg x kg(-1) x day(-1)) or with a low-salt or a high-salt diet (0.02% wt/wt; 8% wt/wt), and COX-2 as well as renin mRNA expression were determined in the ligated and the nonligated contralateral kidney. During ureteral ligation, hydronephrosis developed with a reduction of medullary mass, while the cortex was preserved. Expressions of the Na-K-2Cl cotransporter isoforms A and B were both reduced in the hydronephrotic cortex to 70 and 35% of the corresponding contralateral intact kidney. Despite the abrogation of glomerular filtration, detected by inulin clearance measurements, renocortical COX-2 mRNA abundance was stimulated by furosemide treatment (3.2-fold) or low-salt diet (2.9-fold) to similar degrees compared with the intact contralateral kidney (2.7-fold for both treatments), whereas a high-salt diet did not significantly suppress COX-2 mRNA in the macula densa region of either kidney. Renin mRNA expression was regulated strictly in parallel in both kidneys, a low-salt diet or furosemide treatment stimulating and a high-salt diet suppressing it. We conclude from these findings that salt delivery to the tubules is not an essential requirement for the upregulation of COX-2 by salt deficiency or by loop diuretics in the rat kidney cortex nor is it for chronic stimulation of renin mRNA expression.
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PMID:Upregulation of macula densa cyclooxygenase-2 expression is not dependent on glomerular filtration. 1518 Sep 25


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