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

The prevalence of kidney stones has steadily risen during this century; passage of a calculus and a positive family history increase the probability of recurrence. Findings from recent studies on the cause of renal calculi have stressed crystallization and crystal aggregation of stone minerals from supersaturated urine, rather than excessive organic matrix. Absence of normal urine inhibitors of calcium salts is also stressed. Formation of calcium oxalate stones is the major problem. Therapy with decreased calcium and oxalate intake, thiazides, phosphate salts and allopurinol in various combinations has substantially decreased the prevalence of recurrent stones. The rationale for the use of allopurinol is that uric acid salts enhance the tendency for calcium oxalate to crystallize from supersaturated urine. The hypercalciuria seen in 30 percent to 40 percent of patients with oxalate stones is usually caused by intestinal hyperabsorption of calcium. Although patients with uric acid calculi constitute only a small fraction of those in whom stones form, they represent a group in whom good medical therapy, based on sound physiologic principles, has proved extremely successful. Renal tubular syndromes lead to nephrocalcinosis and lithiasis through hypercalciuria, alkaline urine and hypocitraturia, the latter an inhibitor of calcium salt precipitation. Recent advances in surgical techniques are discussed, including the rationale for removing staghorn calculi. The ileal ureter and coagulum pyelolithotomy deserve special emphasis.
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PMID:Kidney stones. 738 35

Two hundred and twenty ureteric stones in 214 patients were fragmented intracorporeally by pneumatic lithotripsy under general/regional anaesthesia in a day care set-up. Patients were followed-up weekly and retreatment was done at 4 weeks where necessary. Majority (77%) of patients were in the age group 21-40 years with a male to female ratio of 2:1. Stone location was 86% in the lower third, 11% in the middle and 3% in the upper third ureter. Size of stones was less than 6 mm in 14%, 7-12 mm in 67% and more than 20 mm in 4% cases. All 81% stones of < 12 mm were fragmented in one treatment session while single treatment rate for stones 13-18 mm was 85% and 44% for more than 20 mm size. Overall non-fragmentation rate was 0.9%. Stone free state at four weeks was 95%. Complications were observed in 8.6% cases which included urosepsis, haematuria and perforations. Infrared spectroscopy (IR) in 45 stones showed majority (64%) to be composed of calcium oxalate. Our experience shows that PL is a safe and effective means of performing intracorporeal lithotripsy for both large and hard ureteric stones.
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PMID:Pneumatic lithotripsy: a new modality for treatment of ureteric stones. 773 Oct 87

It has been reported that up to half of renal stones and associated urine specimens have been positive on culture, and that up to 50% of such stones contain magnesium ammonium phosphate. In a prospective study using infrared and wet chemical analysis, we found positive cultures in only 7 of 132 renal, 5 of 105 ureteral and 6 of 21 bladder stones obtained surgically and handled with sterility. Of the culture positive calculi only 43% from the kidney, none from the ureter and 50% from the bladder contained detectable magnesium ammonium phosphate. However, magnesium ammonium phosphate was detectable in 20% of renal, 2% of ureteral and 27% of bladder stones with negative cultures. Of the culture positive renal and ureteral calculi 42% were predominantly calcium phosphate and 17% were predominantly calcium oxalate. For culture negative stones 25% and 51% from the kidney, and 15% and 82% from the ureter were composed of predominantly calcium phosphate and calcium oxalate, respectively. Among the culture positive stones, related positive urine cultures were noted in 100% of the renal, 20% of the ureteral and 50% of the bladder cases, compared to 26%, 10% and 27%, respectively, of culture negative calculi. The same organism was found in the stone and urine in only 38% of the cases. The lower frequency of positive urine cultures, of stones with magnesium ammonium phosphate, and especially of culture positive renal and ureteral stones (5%) than in previous reports suggests that stone culture may be of less value than indicated previously, except for bladder calculi and large renal stones, such as the branched type.
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PMID:Bacteriology of urinary tract stones. 786 88

The relation of chemical composition and structure of uroliths to lithotripsy effects was evaluated with regard to the concrement size, location, time of the intraureteral persistence, etc. Besides, a prognosis of the remote impulse lithotripsy (RIL) outcome was attempted by x-ray picture and crystallization alterations in the urine. 54 patients with nephroliths and 73 patients with ureteroliths (overall 137 concrements) were examined. By RIL results, the patients were divided into 2 groups: those who benefited from RIL and those who failed it. Worse results were obtained in cases of oxalate concrements with radial-concentric structure and with phosphate ones composed primarily of hydroxylapathite. RIL efficacy was found to depend on a number of interrelated factors (chemical structure, location, size of the concrement, duration of its existence in the ureter). In long-standing ureteroliths the outcomes are associated with stone structure. The denser is the concrement the more probable is its strangulation and more apparent is periureteritis. Changes in crystallization can prompt RIL prognosis as well as it is possible by x-ray picture.
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PMID:[The effect of the physicochemical structural properties of urinary calculi on the results of extracorporeal shockwave lithotripsy]. 820 63

The Electromechanical Impactor was conceived as a safe and effective device for intracorporeal stone fragmentation. It is a 3 French EHL electrode enclosed within a stainless steel sheath. The interior is irrigated with saline. Discharge of the system causes an EHL spark which vaporizes saline and produces a cavitation bubble and subsequent shock wave. The shock wave propels a conical titanium tip forward for a distance of 2.7 mm with an impact pressure of 900 bar. Bench and animal testing has proven its effectiveness for stone fragmentation and safety for use within the ureter. The mean lifetime of each probe is approximately 700 pulses. It is used under direct vision through the straight operating port of a rigid or semi-rigid 9.5 French ureteroscope. Clinical studies at the Massachusetts General Hospital (reported herein) and the Mayo Clinic demonstrate approximately 90% efficacy. It is especially effective on cystine, calcium oxalate dihydrate, struvite and mixed calcium oxalate monohydrate calculi. Shiny-smooth black calcium oxalate monohydrate calculi will fragment but are more resistant. There has been no evidence of ureteral wall injury. The EMI is currently 5 French and is used both safely and effectively under direct vision of fragment ureteral calculi. Larger sizes are designed for percutaneous use and for bladder stone fragmentation.
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PMID:The electromechanical impactor: a new device for intracorporeal stone fragmentation. 834 87

The Browne Pneumatic Impactor (BPI; Browne Medical Systems, Minneapolis, MN) is a new mechanical lithotripter that relies on a pneumatically driven metal probe. It can be employed through both rigid and actively deflectable flexible endoscopes. Prior in vivo studies have shown excellent fragmentation of hard human calculi while employing the BPI with active endoscope deflection of as much as 45 degrees. In this study, we set out to define the efficiency of stone fragmentation with active endoscope deflection and to quantify the extent of retrograde stone migration that is often noted when mechanical lithotripters are employed. Pressure transducer testing of the BPI revealed an inverse relation between increased deflection of the endoscope and transduced voltage. Calculus fragmentation tests showed that as the endoscope was actively deflected to 90 degrees, the BPI still was able to fragment human calcium oxalate monohydrate calculi into extractable fragments with as few as six pulses. The maximum active endoscope deflection was 95 degrees with the 0.020-inch Nitinol probe passed through the working channel. At this deflection, the BPI was able to fragment an 8 mm pure calcium oxalate monohydrate calculus into two fragments after 14 pulses. Retrograde migration was evaluated by employing the BPI in a simulated ureter in a waterbath. The travel distance of a 5-mm 5-g calculus with one pulse averaged 12.2 mm (range 1-44 mm). Smaller, less dense calculi travelled farther. A rebound effect was occasionally noted, and this was associated with an off-center delivery. In conclusion, the BPI is an efficient mechanical lithotrite able to fragment hard human calculi when employed with active endoscope deflection of as much as 95 degrees. Delivered energy decreased with active endoscope deflection, but this change did not prevent fragmentation. Retrograde migration was an important variable more notable with smaller calculi.
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PMID:Mechanical impactor employing Nitinol probes to fragment human calculi: fragmentation efficiency with flexible endoscope deflection. 858 Sep 34

The effects of Ca(2+)-precipitating anions (oxalate and phosphate) and effective inhibitors of endo/sarcoplasmic reticulum calcium pump (thapsigargin and cyclopiazonic acid) on azide-insensitive (5 mM) Mg2+,ATP-dependent Ca2+ accumulation in microsomes of ureter smooth muscle cells were studied. Oxalate (0-20 mM) and phosphate (0-60 mM) stimulate Mg2+,ATP-dependent Ca2+ accumulation. Thapsigargin and cyclopiazonic acid at 100 nM and 20 microM, respectively, completely inhibited (i.e., down to the level in the absence of oxalate) Ca2+ accumulation activated by 10 nM oxalate. These inhibitors only partially inhibited Ca2+ accumulation activated by 40 mM phosphate. Mg2+,ATP-dependent Ca2+ accumulation in microsomes, which is inhibited by thapsigargin and cyclopiazonic acid and activated by oxalate or phosphate, can result from functioning of calcium pump in endoplasmic reticulum of ureter myocytes. The inhibition constant, Ki, was calculated by the method of Hill and it was 0.3 nM and 0.2 microM for thapsigargin or cyclopiazonic acid, respectively. Mg2+,ATP-dependent Ca2+ accumulation in microsomes, which is insensitive to thapsigargin or cyclopiazonic acid and activated by phosphate, can result from functioning of calcium pump in plasma membranes of ureter myocytes.
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PMID:[Two components of sodium-azide insensitive Mg2+,ATP-dependent Ca2+ transport in ureteral smooth muscle membrane structures]. 903 37

28 patients with long-standing ureteroliths (present in the ureter for 2 months and longer, size 0.8-1.5 cm) were exposed to extracorporeal impulse lithotripsy (EIL). 26 of them were found to have inflammation in the kidneys and upper urinary tracts. Comparative data on EIL effect show that patients with long-standing ureteroliths need more intensive and long EIL treatment, that fragmentation is more troublesome in oxalate monohydrates and phosphate stones with hydroxylapatite. 4 cases eventuated in operative intervention, in 3 cases ureterolith extraction was performed. EIL results in long-standing ureteroliths depend on the presence of renal and urinary tract inflammation, severity of periureteritis, chemical composition, density and structure of the stones.
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PMID:[Extracorporeal shockwave lithotripsy in patients with the long-term presence of stones in the ureter]. 905 2

Forty-five patients with 46 ureteral stones were treated using a new pulsed dye laser (Pulsolith, TMI). A fiber of 250 micrometers was used through rigid (40 cases) or flexible (6 cases) ureteroscopes. Stones were located in the upper third (5 cases), middle third (5 cases), or lower third (36 cases) of the ureter. Stone composition was calcium oxalate dihydrate or monohydrate, struvite, or uric acid in 34, 7, 2, and 2 patients, respectively. Thirty-six stones (78%) were fragmented, including 14 cases that required basket removal of fragments at the same time. Ten stones were not fragmented, 6 because of the pure monohydrate composition and 4 due to a laser breakdown. No damage to the ureteral wall was noted. Retrograde rigid ureteroscopy with laser lithotripsy was effective for lower and middle third ureteral stones. Flexible ureteroscopy with laser lithotripsy was effective (impacted stones) but difficult for upper third ureteral stones. Laser lithotripsy was not effective for pure calcium oxalate monohydrate stones.
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PMID:Clinical experience with a new pulsed dye laser for ureteral stone lithotripsy. 1015 Jan 27

A 32-year-old man consulted Osaka National hospital with chief complaints of dysuria and macrohematuria. DIP and CT revealed that the right kidney deviated to the lower pole of the left kidney and they fused together. The right ureter crossed over the supine. The calcified shadow existed in the lower end of the left ureter with cobra head image. He had no external anomalies. Under diagnosing crossed fused kidney (inverted L shaped) complicated the left ureterocele with a stone, transurethral incision of ureterocele (TUI) was performed. We made transverse incision and extracted stone, 7 mm in size (calcium oxalate 96% and calcium phosphate 4%). Three months later after the operation, IVP, CG and VCG revealed the down-sized ureterocele and no VUR. Crossed renal ectopia complicated many anomalies about 50%. Among them anomalies of the urinary tract was most frequent about 30%. But crossed renal ectopia with ureterocele wasn't reported so far in Japanese literature.
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PMID:[A case of crossed fused kidney with simple ureterocele]. 1065 64


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