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

In six dogs, a segment of the right ureter was replaced by a tubular segment of poly [L(-) lactic acid], a new absorbable biomaterial, with the hope that the foreign body would be absorbed or dissolved after a new mucosally lined channel had formed. The dogs were followed with excretory urograms, blood urea nitrogens, and serum creatinines. Postoperatively, four of the six dogs had deteriorating or total loss of function of the right kidney by 8 months attributable to obstruction of the ureter by disintegrating implant.
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PMID:Biodegradable ureteral grafts in dogs. 68 37

The mammalian renal pelvis has previously been regarded as having no physiological function other than that of a receptacle for the urine before it moves through the ureter. It has long been known that the renal pelvis in mammals shows elaborate extensions that bring the urine in intimate contact with outer and inner medullary tissue. The epithelium covering these areas is of a type that indicates that transport of solutes and water can take place across it. Physiological studies have shown that urea and water readily move across the renal papillary epithelium. The pronounced ability of ruminants to conserve urea when placed on a low protein diet coincides with a highly developed renal pelvis with specialized fornices and secondary pouches. It is suggested that urea conservation in low protein animals takes place partly in the renal pelvic extensions where urea is returned to the blood. A hypothesis is also proposed for the concentrating mechanism in which recycling of urea from the pelvic urine across the papillary epithelium plays an important role.
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PMID:Excretion in mammals: role of the renal pelvis in the modification of the urinary concentration and composition. 90 83

The authors report 22 cases of uretero-ileo-plasty for uretero-hydronephrosis due to schistosomiasis. The indications for operation depend on the following criteria: the degree of dilatation which varies from simple atonia to very large hydronephrosis which one must not wait for, ureteral stenosis, vesico-ureteral reflux, the degree of renal failure assessed by studies of creatinine and urea clearance and the resistance to treatment. The operative technique which is not specific for bilharziasis includes uretero-ileo-plasty which is often bilateral, for even in asymmetrical cases, the least affected ureter is often of poor quality. There were failures in two cases due to irreversible renal failure, and in two cases, due to peritonitis. The late results of the other cases appear very favourable: increased vesical capacity, diminution of cystalgia, comfort and improved, general health, were the main factors. Stenosis of the anastomosis, vesico-ureteral reflux and urinary infection, acidosis, lithiasis are rare or not very severe.
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PMID:[Uretero-ileoplasty in bilharzian uretero-hydronephrosis]. 95 96

1. The relative significance of reduced excretion of urinary constituents and reduced renal mass, as stimuli to growth of one kidney after the other has been removed, has been investigated. 2. To abolish the excretory function of one kidney without removing it, the right ureter was drained into the vena cava through a compound cannula for 6 weeks. Uretero-caval anastomoses were performed in twenty-four male rats at 10 weeks of age: six survived without evidence of ureteric obstruction (and a further five with minimal obstruction). 3. The rats with anastomoses grew less than six other rats from which the right kidney had been removed or six which had been submitted to a sham operation, and their plasma urea and creatinine concentrations were higher. 4. Relative to body weight, the dry weight of each kidney after uretero-caval anastomosis without obstruction was 18% greater than after sham operation; taking both kidneys together, the total increase was almost as much as in the left kidney alone after right nephrectomy (46%). 5. Histologically and in terms of DNA concentration, the growth of both kidneys after uretero-caval anastomosis was of the same kind as in the left kidney after right nephrectomy. 6. The return of urine from one kidney into the blood provided a powerful stimulus to renal growth in spite of the restraining effect of increased renal mass.
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PMID:Growth of rats' kidneys after unilateral uretero-caval anastomosis. 97 1

The concentration of major urinary solutes was studied in ureteral urine collected at 15- to 30-s intervals at the onset of acute diuresis induced in anesthetized dogs either by high-ceiling diuretics (mainly ethacrynic acid) or by osmotic diuretics. Phosphate/inulin clearance ratios remained unchanged; potassium/inulin clearance ratios rose rapidly. Principal attention is given to the mechanisms underlying a transient rise in urinary sodium and chloride concentrations during the onset of diuresis. When the data are corrected for washout artifacts from the pelvis and ureter, it can be shown that the initial collection periods are associated with a transient increase in free-water production and by the simultaneous secretion of urea from the interstitium into the tubular fluid. The former coincides in time with the rise in urinary chloride concentration and represents an augmentation of water reabsorbed in the collecting duct, which is relatively impermeable to chloride. Both responses are quantitatively consistent with the transition from a hyperosmotic to isosmotic medullary interstitium.
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PMID:Electrolyte excretion and free-water production during onset of acute diuresis. 113 May 34

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.
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PMID:The structural organization of the kidney of the desert rodent Psammomys obesus. 121 58

The clearance of furosemide (F), whose renal tubular transport shares the classical characteristics of the organic acid system, was determined in dogs with varying degrees of azotemia and compared with tetraethylammonium (TEA), an organic base. Two normal and eight azotemic dogs [blood urea nitrogen (BUN), 12-273] were studied. Azotemia was produced by bilateral uretero-venous anastomoses. The left renal vein and ureter were cannulated and renal blood flow (RBF) was measured by electromagnetic flowmeter. Simultaneous left renal clearances (C) of subpharmacological doses of TEA-14C and furosemide-14C were determined at seven 30-minute intervals. Initial loading doses were followed by continuous maintenance infusions. For TEA, clearance (1.5 ml/min-g +/- 0.2 S.E.M.) and extraction (E) (0.83 +/- 0.02) are independent of the degree of azotemia. Renal plasma flow (RPF), calculated as CTEA/ETEA, agreed closely with directly measured RPF (2.0 ml/g-min +/- 0.3). RPF was independent of azotemia. To allow for individual differences in the animals in RPF, the ratio CTEA/CF was used. CF (1.07-0.17 ml/min-g) and EF (0.54-0.06) decreased as a linear function of the increase in uremic serum: (see article). Furosemide and its principle metabolite were greater than or equal to 97% of the furosemide portion of the radioactivity. The metabolite did not increase with time in either plasma or urine. After acute administration of exogenous urea to two dogs (BUN 170 and 253) CTEA/CF was unrelated to BUN. Thus, the CF decreases proportionately with progressive azotemia and is not related to RBF, exogenous urea or metabolite. This suppression of renal tubular secretion of furosemide may partially account for reduced therapeutic efficacy of furosemide in azotemia.
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PMID:Effect of experimental azotemia on renal clearance of furosemide in the dog. 124 13

Dogs were made azotemic by bilateral ureteral-venous anastomosis. Subsequently, the left ureter, a systemic artery, and the left renal vein were cannulated. Left renal blood flow (RBF) was measured by an electromagnetic flowmeter. Left renal clearances and extractions of [14C]tetraethylammonium ([14C]TEA) and p-aminohippuric acid (PAH) were determined at five 40-min intervals after administraiton of loading doses and institution of a maintenance infusion containing PAH and [14C]TEA. The renal extraction of TEA was independent of blood urea nitrogen (BUN), whereas the extraction of PAH correlated inversely with BUN. Renal plasma flows calculated from urinary clearances and renal extractions agreed with renal plasma flows calculated from flowmeter data. The extraction of TEA remained constant over the 200-min experimental period, whereas the extraction of PAH increases progressively as a function of time. It is probable that those organic acids which accumulate in azotemia, and interfered with renal tubular secretion of PAH, were themselves eliminated after opening the ureteral-venous anastomosis. Thus, TEA is superior to PAH for evaluation of the renal circulation in azotemia.
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PMID:Effects of azotemia on renal extraction and clearance of PAH and TEA. 126 21

A 1.5-year-old male Belgian Malinosis Military Working Dog presented with a 1-month history of intermittent hematuria. Diagnostic ultrasound and contrast radiography demonstrated large blood clots in the urinary bladder and a filling defect in the right renal pelvis. At surgery, clotted blood was present in the right ureter and bladder. Following right nephrectomy, the dog returned to training. One month later, elevations in urea nitrogen and creatinine were noted. Hematuria recurred at 3 months and the dog was found dead in its kennel. Necropsy showed a blood-filled left renal pelvis and ureter.
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PMID:Idiopathic renal hematuria in a military working dog. 145 85

To assess the role of androgen receptors (ARs) in the expression of androgen-dependent seminal vesicle (SV) secretory proteins, tissue recombinants were prepared with rat seminal vesicle mesenchyme plus ureter epithelium of wild-type or Tfm mice (rat SVM plus wild-type mouse URE and rat SVM plus Tfm mouse URE, respectively). After growth in male hosts, both the wild-type and Tfm ureter epithelia were induced by SVM to differentiate into a simple columnar epithelium exhibiting the complex folded morphology characteristic of the SV. In SVM plus wild-type mouse URE recombinants, epithelial ARs were induced, and the epithelium expressed the full spectrum of SV secretory proteins. By contrast, in SVM plus Tfm mouse URE recombinants, the Tfm epithelium was genetically incapable of producing functional ARs and failed to produce SV secretory proteins. These data demonstrate in vivo that the induction of SV secretory proteins by androgens is an event requiring intraepithelial ARs. In contrast, androgen-dependent epithelial morphogenesis, columnar cytodifferentiation, and probably also proliferation can be expressed in Tfm epithelium grown in association with wild-type mesenchyme, strongly suggesting that these events are indirect effects on the epithelium mediated by mesenchymal ARs.
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PMID:Inability of Tfm (testicular feminization) epithelial cells to express androgen-dependent seminal vesicle secretory proteins in chimeric tissue recombinants. 203 92


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