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PubMed1995

Vascular anatomy of the rabbit ureter.

BACKGROUND: The success of kidney transplant surgery and ureteral reconstruction requires the preservation of the ureteral blood supply. Because of its potential vulnerability to surgical trauma during transplant and reconstructive surgery, the ureteral vasculature merits a full anatomical description. METHODS: The microvascular anatomy of the ureter was studied in male New Zealand white rabbits by light microscopy and transmission electron microscopy and scanning electron microscopy of vascular corrosion casts and alkali digested tissue. RESULTS: The rabbit ureter is supplied predominantly by a branch of the renal artery proximally (cranial ureteral artery) and by a branch of the vesicular artery distally (caudal ureteral artery). Minor vascular continuities are also present between the capillary beds of the ureter and those of the renal pelvis cranially and the bladder wall caudally. There are no external vascular connections to the middle ureter with the exception of a single, small vein which drains into the inferior vena cava. A single group of longitudinal arteries and veins runs the full length of the ureter within the adventitia. Branches of these longitudinal vessels pass tangentially through the muscularis to supply a vascular complex within the lamina propria. This complex in turn supports a rich, mucosal capillary plexus located at the junction between the transitional epithelium and the lamina propria. In the fixed ureter the capillary plexus lies in grooves formed by displacement of the basal layers of the overlying transitional epithelium. The capillaries are continuous or fenestrated, are often invested with pericytes, and are distributed uniformly around the entire circumference of the ureter. CONCLUSIONS: The ureteral vasculature exhibits several unique features related to its function in urine conduction and its ability to accommodate expansion and contraction. The combination of techniques used provides a clear three-dimensional view of this vasculature. Our findings also confirm that, because of its limited blood supply, the ureter may be very susceptible to injury during renal transplantation or other abdominal surgery.

Animals↗
PubMed1994

Effect of Bay K 8644 and ryanodine on the refractory period, action potential and mechanical response of the guinea-pig ureter to electrical stimulation.

We have investigated the effect of the dihydropyridine calcium channel agonist, Bay K 8644, and of the plant alkaloid blocker of calcium-induced calcium release (CICR) from the sarcoplasmic reticulum, ryanodine, on the refractory period, action potential and mechanical response of the guinea-pig isolated ureter to electrical stimulation. All experiments were performed in ureters pre-exposed to 10 microM capsaicin to eliminate the inhibitory influence exerted by local release of sensory neuropeptides on ureteral excitability and contraction. In organ bath experiments, electrical field stimulation with parameters which produce direct excitation of ureteral smooth muscle (train of pulses at 10 Hz, 5 ms pulse width, 60 V for 1 s) produced tetrodotoxin- (1 microM) resistant phasic contractions. The response to EFS was abolished by nifedipine (1 nM-3 microM) and was enhanced by Bay K 8644 (1 nM-3 microM). In the presence of Bay K 8644 (1 microM), nifedipine (30 microM) abolished the evoked contractions. Ryanodine (10-100 microM) had no significant effect on the amplitude of evoked contraction. The response of the guinea-pig ureter to direct electrical stimulation of smooth muscle is characterized by a refractory period: at least 40 s interstimulus interval was required to produce a second response in all preparations tested. Bay K 8644 (1 microM) markedly reduced the refractory period of the ureter and a similar effect was observed with ryanodine (100 microM). To further analyze the effect of Bay K 8644 and ryanodine on the refractory period, the response of the ureter was investigated over a 10 s period of stimulation (other parameters as above). In control ureters, continuous stimulation for 10 s produced only one phasic contraction just after the beginning of the train of stimuli. In the presence of Bay K 8644 or ryanodine, more than one phasic contraction developed during a 10 s stimulation, i.e. the refractory period became shorter than the train duration. When both Bay K 8644 and ryanodine were tested on the same preparations, an additive excitatory effect was observed on the mechanical response to electrical stimulation. A slight elevation of KCl concentration (5-10 mM) reduced the refractory period of the ureter as observed with ryanodine or Bay K 8644. Application of KCl (80 mM) produced a biphasic contractile response of the ureter: a series of phasic contractions occurred first, which were then replaced by a slowly developing tonic response. Bay K 8644 (1 microM) enhanced both components of the response to KCl. Ryanodine (10 and 100 microM) markedly prolonged the duration of phasic contractions evoked by KCl and, at 100 microM, slightly (about 25%) reduced the amplitude of tonic contraction.(ABSTRACT TRUNCATED AT 400 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1999

Renal transplantation from a living related donor with a retrocaval ureter--a note of caution.

In our study we describe a renal transplant from a living related donor who was found to have a retrocaval ureter. The retrocaval ureter is a rare congenital anomaly resulting from a defect in the embryological development of the ureter and the inferior vena cava (IVC). The compression of the ureter between the IVC and the vertebrae can result in progressive hydronephrosis. The non-dilated segment of the ureter was used for the uretero-neocystostomy. The patient presented with ureteric obstruction in the immediate post-transplant period, and at surgical exploration the ureteroneocystostomy was revised using the dilated portion of the ureter. We recommend that when transplanting a kidney with a retrocaval ureter, caution should be exercised in using the non-dilated portion of the ureter, since either the blood supply may be compromised or the peristalsis may be interrupted.

Adult↗
PubMed1992

Presence and regional variation in peptide-containing nerves in the human ureter.

The occurrence, distribution and regional variation of neurones immunoreactive for the neuropeptides, vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), enkephalin (ENK), calcitonin gene-related peptide (CGRP), and substance P (SP) were investigated in human ureters by indirect immunohistochemistry. In addition, immunoreactivities to tyrosine hydroxylase (TH), a marker of noradrenergic neurones and to protein gene product (PGP) 9.5, a general marker of neurones, were also studied. Neurones displaying PGP-, NPY-, VIP- and TH-like immunoreactivity (-LIR) provided a rich innervation to the smooth muscle and blood vessels of the ureter, where they formed dense muscular and perivascular nerve plexuses. In contrast, there was only a moderate to sparse innervation by SP and CGRP-LIR neurones, most of which were distributed to blood vessels and to the sub mucosal layer, and only rarely to smooth muscle bundles. No ENK-LIR was detected in this study. Nerve fibre bundle densities were estimated for each of the localized neurochemicals according to a method described. NPY-LIR nerve fibre bundles were found to account for 80% of the total nerve fibre bundles (i.e. PGP-LIR) in the ureter. On the other hand, TH-LIR and VIP-LIR nerve fibre bundles each accounted for 50% of the total ureteral innervation, whereas SP- and CGRP-LIR nerve fibre bundles each comprised 20% of the total innervation. The abundance and pattern of tissues innervated by these immunoreactive neurones is consistent with the view that some of these neuropeptide substances co-exist with other peptide substances and/or with other known neurotransmitters, such as noradrenaline or acetylcholine. A gradient of innervation was found to exist for all the neurochemicals demonstrated in the ureter, whereby the lower ureter receives a greater density of innervation than the upper ureter. This finding suggests the human ureter is primarily innervated by fibres arising from or via the lower pelvis, i.e. the pelvic plexus. It also supports the view that the lower ureter may perform an important physiological role, such as coordinating the tone of this region during bladder filling and emptying.

Adult↗
PubMed1994

Patterns of neuronal colocalisation of tyrosine hydroxylase, neuropeptide Y, vasoactive intestinal polypeptide, calcitonin gene-related peptide and substance P in human ureter.

The patterns of colocalisation of neuropeptides, tyrosine hydroxylase (TH), and protein gene product 9.5 (PGP), were studied in nerve fibres supplying the upper and lower human ureter using a double labelling immunofluorescence technique. The majority (85%-95%) of nerve fibres within the ureter contained neuropeptide Y-like immunoreactivity (NPY-LIR), in combination with other peptides. Approximately 52%-63% of the total ureteral innervation was made up of NPY-LIR fibres also expressing TH-LIR, while 21%-42% of fibres contained NPY-LIR in combination with vasoactive intestinal polypeptide (VIP)-LIR. These two immunochemically defined classes did not overlap, since TH- and VIP-LIR were never present within the same nerve fibre. Other minor populations of neurones included those containing calcitonin gene-related peptide (CGRP)-LIR in combination with substance P (SP)-LIR (4%-17%) and those without SP (5%). Rare coexistences were also noted between CGRP- and VIP-LIR (1%-2%), CGRP- and NPY-LIR (< or = 1%), and CGRP- and TH-LIR (< 1%). Regional differences in innervation were found. There were fewer of each class of nerve fibres in the upper ureter compared to the lower ureter. In addition, the proportion of VIP/NPY-LIR fibres of the total innervation was less in the upper ureter, where they were very sparse. Differences in the distribution to various tissue targets were also observed. In the lower ureter, TH/NPY-LIR fibres were localised predominantly to the outer muscle fascicles and adventitia, while VIP/NPY immunoreactive nerves supplied the submucosa and inner smooth muscle fascicles. Both of these populations were also found around blood vessels. A population of presumptive sensory fibres expressing CGRP/SP-LIR were typically present immediately beneath the urinary epithelium and around blood vessels, and only very rarely within muscle fascicles. The finding that TH/NPY- and VIP/NPY-LIR fibres innervate different layers of the ureter raises the possibility that the muscle layers of the ureter may be independently controlled.

Aged↗
PubMed2001

Systemic and topical drug administration in the pig ureter: effect of phosphodiesterase inhibitors alpha1, beta and beta2-adrenergic receptor agonists and antagonists on the frequency and amplitude of ureteral contractions.

PURPOSE: We searched for compounds that are pharmacologically active on ureteral motility for treating ureteral colic to ease retrograde access into the ureter and improve the clearance of stones or stone particles from the ureter. The effects of the alpha1-adrenergic receptor agonist phenylephrine, the nonselective beta and beta2-adrenergic receptor agonists isoproterenol and fenoterol, and the phosphodiesterase inhibitors papaverine (nonspecific) and rolipram (type IV) on the frequency and amplitude of ureteral contractions when administered intravenously or topically were investigated in pigs. MATERIALS AND METHODS: A total of 52 pigs were anesthetized. A double lumen 6Fr catheter was inserted through each renal pelvis and into the ureter, allowing perfusion of saline or drug solution into the renal pelvis and the recording of contractions from the mid portion of the ureter. RESULTS: The alpha1 and beta-adrenergic receptors of the ureter are not tonically activated by endogenous epinephrine or norepinephrine. Phenylephrine administered intravenously at a dose of 0.01 to 3 mg./kg. and topically at 0.1 to 3 mg./ml. per minute increased contraction frequency 10 and 4-fold, respectively, and contraction amplitude 2-fold each in a dose dependent manner. Arterial blood pressure increased markedly during intravenous administration of phenylephrine but was minimally affected during topical application. The phenylephrine effects were reversed by the antagonist prazosin. Isoproterenol administered intravenously at a dose of 0.01 to 10 mg./kg. and topically at 0.1 to 200 microg./ml. per minute decreased contraction frequency to 13% and 31% of controls, respectively. Contraction amplitude was not affected by intravenous administration but decreased to 59% of controls when applied topically. These effects were also observed with a slight delay in the saline perfused contralateral ureter. The heart rate also increased, suggesting absorption of the drug by the urothelium. The isoproterenol effects were blocked by the antagonist propranolol. Fenoterol administered intravenously at a dose of 0.1 to 30 microg./kg. and topically at 0.003 to 1 mg./ml. per minute decreased contraction frequency to 14% and 10% of controls, and contraction amplitude to 84% and 65%, respectively. These effects on the drug perfused ureter were also observed on the contralateral saline perfused ureter but to a lesser extent. The fenoterol effects were blocked by the antagonist propranolol. Papaverine administered intravenously at a dose of 0.001 to 3 mg./kg. decreased contraction frequency to 33% of controls. Topically administered papaverine as well as intravenous and topically administered rolipram had no relevant effect on ureteral motility. CONCLUSIONS: Intravenous phenylephrine increases, and isoproterenol and fenoterol decrease the frequency and amplitude of ureteral contractions in the pig. The same effects are observed with the topical administration of phenylephrine, which causes a significant local but not systemic side effect. Topical administration of isoproterenol and fenoterol produced local as well as systemic effects, suggesting absorption by the urothelium. However, to our knowledge a drug that relaxes ureteral peristalsis in pigs without causing systemic side effects has not yet been identified.

Administration, Topical↗
PubMed1994

Calcitonin gene-related peptide (CGRP) regulates excitability and refractory period of the guinea pig ureter.

Previous studies have indicated that calcitonin gene-related peptide (CGRP), released from the peripheral endings of capsaicin-sensitive primary afferent neurons, may play a role as an inhibitory transmitter in the guinea pig ureter. The aim of this study was to compare the effect of capsaicin desensitization and administration of a CGRP receptor antagonist on the excitability and refractory period of the guinea pig ureter to electrical field stimulation. Electrical field stimulation using a long (5 msec.) pulse width produced phasic contractions of the ureter which were unaffected by tetrodotoxin, that is, were produced through direct excitation of ureteral smooth muscle. Human alpha CGRP (1 to 10 nM.) produced a concentration-dependent transient suppression of the evoked contractions, and its effect was prevented by the CGRP receptor antagonist human alpha CGRP(8-37) (1 microM.). In vitro capsaicin pretreatment (10 microM. for 15 minutes) to block neuropeptide release from peripheral endings of sensory nerves or administration of the CGRP receptor antagonist enhanced the responsiveness of the guinea pig ureter to electrical stimulation. In control ureters, the application of two trains of electrical stimuli failed to produce a second contraction at intertrain intervals greater than 20 seconds. The intertrain interval required to obtain a second contraction averaging 50% of the amplitude of the first response (ITI50) of control ureters was about 50 seconds. In vitro capsaicin pretreatment or administration of the CGRP receptor antagonist reduced the refractory period of the ureter to electrical field stimulation: ITI50 averaged 8.8 and 9.1 seconds after capsaicin or CGRP antagonist pretreatment, respectively. These findings demonstrate that capsaicin pretreatment or blockade of CGRP receptors produced qualitatively and quantitatively similar excitatory effects on ureteral excitability and refractory period and are in general agreement with the idea that CGRP is a primary inhibitory transmitter in guinea pig ureter. Inhibition of motility by CGRP could be important for setting the frequency of ureteral peristalsis and suppression of latent pacemakers to prevent the occurrence of antiperistaltic waves.

Animals↗
PubMed1988

Response of normal canine ureter to photodynamic therapy using a cylindrical fiber.

Photodynamic therapy (PDT) was performed utilizing a cylindrical optical fiber to determine feasibility of distal ureteral treatment on 10 study and two control NIH foxhounds. The study animals were administered three mg./kg. dihematoporphyrin ether (Photofrin II) intravenously followed 48 hours later by open cystotomy. One ureter was irradiated with 42 joules of 630 nm. light delivered by a 660 micron diameter optical fiber modified for cylindrical light distribution. Intravenous urography was performed both at three days and six weeks post PDT. Hydroureteronephrosis was revealed in one treated ureter and one untreated ureter. Mild dilatation of the ureter was noted by urography in another treated ureter and in one ureter that did not undergo light irradiation; no distal obstruction was revealed in either case by proximal infusion of saline or by histopathology. Nine of the 10 treated ureters were found to have either no abnormal pathology or only minimal lymphocytic infiltration. In this study, the normal ureter was shown to tolerate photodynamic therapy at energy densities equivalent to those used to effect tumor regression and the feasibility of using a cylindrical optical fiber for treatment of ureteral malignancies was confirmed.

Animals↗
PubMed2002

Intraluminal pressure changes in vivo in the middle and distal pig ureter during propagation of a peristaltic wave.

OBJECTIVES: To establish the characteristics of mechanical activity during ureteral peristalsis and unidirectional bolus transport, pressure changes in the middle and distal (juxtavesical and ureterovesical junction) porcine ureter were quantified in vivo. METHODS: Five female New Yorkshire pigs (50 to 60 kg) were studied under halothane anesthesia. The endoscopic approach was used to position an 8-channel 6 F perfusion catheter under direct vision into the distal ureter by way of the orifice. Ureteral activity was studied in two separate sessions at 1-week intervals. The pressure, propagation velocity, and length of the peristaltic waves were analyzed. RESULTS: The average maximal pressure in a not previously instrumented ureter amounted to 35.7 +/- 1.2 cm H(2)O in the mid-ureter, and decreased to 19.4 +/- 1.3 cm H(2)O in the juxtavesical ureter (P < 0.001) and further to 7.2 +/- 1.0 cm H(2)O (P < 0.001) in the submucosal segment. The propagation velocity of the peristaltic wave through the ureter was 2.1 +/- 1.3 cm/s. The length of the pressure peak was 5.9 +/- 1.6 cm. CONCLUSIONS: A ureteral peristaltic contraction wave travels at approximately 2 cm/s and is approximately 6 cm long. It is responsible for the unidirectional transport of a urinary bolus and itself acts as an "active" antireflux mechanism. The maximal pressure in the lumen of the ureter decreased from proximally to distally, but remains sufficiently high at the ureterovesical junction to prevent retrograde urine leakage when the ureter empties its urinary bolus into the bladder and the orifice is open.

Animals↗
PubMed1992

Endoluminal thermal occlusion of the ureter with the electromagnetic field-focusing device.

The authors attempted ureteral occlusion by means of heat application in nine ureters (24 sites) of New Zealand White rabbits with the electromagnetic field-focusing (EFF) device. The EFF device generates heat at the tip of a grounded probe by focusing eddy currents that have been induced within the tissues by an external radio-frequency field. The power settings were varied from 30 to 150 W. Heat was applied at multiple sites in each ureter. Immediate functional occlusion was seen in all nine ureters. Long-term complete occlusion was seen in six ureters at power settings ranging from 40 to 150 W, while long-term partial occlusion was seen in two ureters at 30-50 W. All sites at 30 W resulted in partial occlusions. Perforation of the ureter resulted in urinoma formation in one ureter at a site that was treated with 150 W. The EFF device can be used to endoluminally occlude the ureter by causing a fibrotic reaction to thermal injury. The effective power range for this application appears to be 40-100 W.

Animals↗
PubMed1998

Ureteric profilometry. A study of the ureteric pressure profile in the normal and pathologic ureter.

The ureteric pressure profile in the normal and pathologic ureter was studied. A 3F ureteric catheter was introduced through the ureteric orifice up to the mid-renal pelvis, and was connected to a pressure transducer. The catheter was pulled down to the urinary bladder and during withdrawal the pressures in the renal pelvis, uretero-pelvic junction (UPJ), ureter, ureterovesical junction (UVJ) and urinary bladder were recorded. The normal ureteric pressure profile started with a peak rise at the UPJ followed by a drop and fluctuations representing the peristaltic waves, and ended with a peak rise at the UVJ. The strictured moderately dilated ureter showed peristaltic waves with irregular rhythm and pressure amplitude, a condition we call "ureteroarryhthmia". The hugely dilated ureter exhibited no waves, i.e. a "silent" profile. The refluxing ureter with normal caliber showed an ureteroarrhythmic pressure profile, while the dilated ureter exhibited either a ureteroarrhythmic or a silent pattern. The study could define a characteristic profilometric pattern for the normal ureter. Two pathologic patterns could be identified: ureteroarrhythmic and silent. Ureteric pressure profilometry is suggested acts as a diagnostic tool in the various pathologic conditions of the ureter.

Adult↗
PubMed1986

Endoscopic correction of primary vesicoureteric reflux: results in 94 ureters.

Sixty one patients with primary vesicoureteric reflux were treated by endoscopic injection of Mentor Polytef paste. Seventy six of the 94 treated ureters showed complete disappearance of vesicoureteric reflux after one injection. Eight refluxing ureters required a second injection, one required a third, and one a fourth. Six ureters showed improvement in the grade of reflux after the first injection. Two ureters did not show any change in the grade of reflux after endoscopic injection. The amount of paste injected to correct reflux in the 94 ureters varied from 0.1 to 1.0 ml (mean 0.33 ml). Patients were followed up for three to 25 months (mean 13.4 months). Follow up micturating cystograms in the 94 ureters showed absence of reflux in 83. Eleven ureters showed recurrence of reflux. Recurrence of reflux was attributed to early technical difficulties and to insufficient amounts of polytef paste used in some cases. Follow up urograms did not show evidence of ureteric obstruction in the treated ureters. Endoscopic injection of polytef paste is a safe, simple, and effective procedure for primary vesicoureteric reflux and averts the need for open operation.

Adolescent↗
PubMed1998

Endoscopic correction of vesicoureteric reflux in failed reimplanted ureters.

PURPOSE: Persistent vesicoureteral reflux (VUR) after reimplantation of ureters requiring reoperation has been reported in up to 7.5% of cases. We report our experience with endoscopic subureteric Teflon injection (STING) in the treatment of VUR after failure of reimplantation of ureters. MATERIALS AND METHODS: Between 1985 and 1995, 31 children (18 male, 13 female) with persistent high-grade VUR after failure of reimplantation of ureters were referred to our hospital for endoscopic correction of VUR. The reflux was unilateral in 22 and bilateral in 9 (40 refluxing units). The ages at the time of STING ranged from 2 to 14 years. Ultrasound and voiding cystourethrography was performed in all patients at 3 months, 1 year and 3 years after STING procedure. Patients were followed-up for periods ranging from 1 to 11 years. RESULTS: VUR was successfully corrected in 27 ureters after a single injection. Seven ureters required two injections and 4 ureters three injections for the correction of reflux. Failure to correct reflux was noted in 2 ureters and these were corrected by reoperation. CONCLUSIONS: STING is a simple and effective day care procedure for the correction of VUR after failure of reimplantation of ureters.

Adolescent↗
PubMed2000

Bone morphogenetic protein 4 regulates the budding site and elongation of the mouse ureter.

In the normal mouse embryo, Bmp4 is expressed in mesenchymal cells surrounding the Wolffian duct (WD) and ureter stalk, whereas bone morphogenetic protein (BMP) type I receptor genes are transcribed either ubiquitously (Alk3) or exclusively in the WD and ureter epithelium (Alk6). Bmp4 heterozygous null mutant mice display, with high penetrance, abnormalities that mimic human congenital anomalies of the kidney and urinary tract (CAKUT), including hypo/dysplastic kidneys, hydroureter, ectopic ureterovesical (UV) junction, and double collecting system. Analysis of mutant embryos suggests that the kidney hypo/dysplasia results from reduced branching of the ureter, whereas the ectopic UV junction and double collecting system are due to ectopic ureteral budding from the WD and accessory budding from the main ureter, respectively. In the cultured metanephros deprived of sulfated glycosaminoglycans (S-GAGs), BMP4-loaded beads partially rescue growth and elongation of the ureter. By contrast, when S-GAGs synthesis is not inhibited, BMP4 beads inhibit ureter branching and expression of Wnt 11, a target of glial cell-derived neurotrophic factor signaling. Thus, Bmp4 has 2 functions in the early morphogenesis of the kidney and urinary tract. One is to inhibit ectopic budding from the WD or the ureter stalk by antagonizing inductive signals from the metanephric mesenchyme to the illegitimate sites on the WD. The other is to promote the elongation of the branching ureter within the metanephros, thereby promoting kidney morphogenesis.

Animals↗
PubMed1988

CT diagnosis of circumcaval ureter.

Variability in the normal course of the ureter makes it difficult to differentiate a normal variant from a congenital anomaly or deviation caused by a mass. CT can be useful in making this distinction. We present five cases of circumcaval ureter in which contrast-enhanced CT, by showing the ureter passing posterior and medial to the inferior vena cava (IVC), provided the definitive diagnosis. In addition, we studied the position of the inferior vena cava in the midlumbar region in 100 consecutive contrast-enhanced CT scans and compared the results with the position of the IVC in our five cases of circumcaval ureter plus one case of circumcaval ureter taken from the literature. Whereas only 6% of the normal patients had an IVC lateral to the right pedicle of the third lumbar vertebra, all of the patients with a circumcaval ureter and the one case in the literature had the IVC lateral to the pedicle. Therefore, the finding of a laterally placed IVC on CT is suggestive but not pathognomonic of circumcaval ureter. Contrast-enhanced CT can be used to prove the diagnosis of circumcaval ureter, and lateral placement of the IVC on non-contrast-enhanced CT suggests the diagnosis.

Adult↗
PubMed2004

Normal ureter size on unenhanced helical CT.

OBJECTIVE: Unenhanced helical CT is the imaging method of choice when evaluating patients with acute flank pain and suspected ureterolithiasis. In addition to directly identifying stones in the lumen of the ureter, CT secondary signs of obstruction such as ureteral dilatation are frequently present and can be helpful in establishing a diagnosis. The purposes of this study were to define ureteral dilatation on unenhanced helical CT and determine the range of normal ureter size. MATERIALS AND METHODS: We retrospectively reviewed the unenhanced helical CT studies of 212 consecutive patients with acute flank pain whose CT scans showed acute ureterolithiasis. The size of the ureter was determined on the asymptomatic side as well as on the obstructed side. Mean ureteral diameter was determined as the largest transverse dimension along the course of the ureter beginning 1-2 cm below the ureteropelvic junction. RESULTS: The mean size of ureters on the asymptomatic side was 1.8 mm with a standard deviation (SD) of 0.9 mm. The mean size of ureters on the obstructed side was 7 mm with an SD of 3.2 mm. In 96% of patients, the ureter diameter on the asymptomatic side was 3 mm or smaller. CONCLUSION: Three millimeters should be considered the upper limit of normal size for nonobstructed ureters on unenhanced helical CT.

Dilatation, Pathologic↗
PubMed1989

[Mechanical property of the human ureter].

This paper is the 10th report in a series of studies on the application of microexplosion to medicine and biology. In the application of microexplosion for destruction of ureteral calculi, the mechanical property of the ureter is an important factor for the prevention of complication. To clarify the factor in humans, tensile and expansive tests were performed on the middle portion of the normal ureter taken from fresh cadavers. Tensile test: Tensile test was performed using 11 ureters in the longitudinal direction and 7 in the transverse direction. 1) In the both directions a 3-phase curve was obtained between the elongation of the specimen and the load, turning at the two yield points. It was presumed that a small part of the mural element of the ureter was first torn at the first yield point, then all the element followed at the second point. 2) At the each yield point the tensile strength and maximum tensile stress of the transverse direction of the ureter were weaker than those of the longitudinal direction, although the elongation ratio at the two yield points was similar in the both directions. It was presumed, accordingly, that ureteral injury first occurred in the transverse direction. 3) The maximum tensile stress of the ureter was higher than that of the bladder. Expansive test: Expansive test was performed using 10 ureters. 1) At a leakage point, the internal pressure of the ureter was 1.9 kgf/cm2 and the internal diameter was 6.4 mm on average. 2) At the leakage point, the tensile strength and elongation ratio of the external diameter were 0.71 kgf/cm and 0.80 on average, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

[Arterial and venous vascularization of cow's ureter in the fetal and neonatal periods].

Investigations of ureter perfusion in cattle during fetal and neonatal period were carried out on 84 fetuses and 10 female newborn cattle. The fetuses 78-1000 mm long were of the 9th-40th week of pregnancy, whereas the newborn ones were 2 or 14 days old. Pelvis blood vessels were filled with rubber latex stained with pigment. This was obtained with the help of a special automatic injector made by ourselves. After coagulation of injection substance the blood vessels were examined under a stereoscopic microscope, some microsurgical instruments adapted to our needs were used. The analysis of morphology and artery developmental markers as well as of ureter veins was carried out with reference to its proximal, middle and distal parts. On the basis of the results it was noticed that transformations of investigated vessels referred mainly to their number. place, kind of ostium and the area of ureter perfusion. Quantitative transformations of analyzed vessels occur first of all in fetuses of the 13th-40th week of pregnancy. Apart from main ureteral+ branches of examined organs as components of renal artery and vein, ovarian artery and vein. uterine branch of vaginal artery and vein, and umbilical artery, they have additional uretal branches, which at the end of pregnancy are reduced and do not take part in the ureter perfusion in newborn cattle. Main uretal branches occur both in fetuses and newborn cattle and they are characterized by increasing occurrence and tendency to widen perfusion range of the ureter wall. The average image of ureter arteries and veins, observed in the oldest fetuses (40th week of pregnancy) and newborn cattle, is similar to the species standard for the mature cattle as presented in other works. There are, however, different results of observations which are due to constant developmental and individual changes of the examined fetuses.

Animals↗