Porcine Urinary Tract Research Articles

Evaluation of urine dipstick tests in experimental porcine urinary tract infection with uropathogenic Escherichia coli

Urinary tract infection is a common disease in pigs and a major reason for sows to be culled. The disease, however, is difficult to diagnose due to lack of distinct clinical signs in the animals. We evaluated the diagnostic value of two commercial urine dipstick tests in 10 pigs using an experimental model of Escherichia coli urinary tract infection. Urine collected at baseline and 48 h after inoculation were analyzed. We show that dipstick tests positive of blood, leucocytes and particularly nitrite are very specific for E. coli UTI with a 100% positive predictive value.

Occlusive Properties of Transrenal Ureteral Occlusion Self-Expandable Metallic Stents: 3D-Printed Phantom and Ex Vivo Studies

Newly developed transrenal ureteral occlusion self-expanding metallic stents (SEMSs) are applied in patients with inoperable fistulas. In this study, the occlusive properties of M- and D-type occlusion SEMSs were investigated in 3D-printed phantom and ex vivo porcine urinary tracts. In the former, the mean bursting pressure causing leakage of contrast medium through the occlusion SEMS was relatively higher in M-types (42.8 ± 3.8 mmHg) than in D-types (38.8 ± 3.8 mmHg), without a statistical difference (p = 0.075). In the latter, the bursting pressure causing leakage through the M-type occlusion SEMS (110.7 ± 8.6 mmHg) was significantly higher than that of the D-type occlusion SEMS (93.8 ± 11.2 mmHg, p = 0.015); however, the mean bursting pressures causing contrast blowout did not differ between the two types (178.7 ± 11.2 mmHg vs. 176.2 ± 11.8 mmHg, p = 0.715). In conclusion, M- and D-type occlusion SEMSs showed similar efficacy in occlusive properties in the 3D phantom study; however, the M-type was superior in the ex vivo porcine urinary tract model. Further in vivo experimental studies are required to confirm these experimental results.

Phenotypic, molecular and genomic characterization of Actinobaculum suis isolated from swine in Brazil

Urinary tract infections (UTI) are considered one of the most important diseases of sows due to its close relationship with reproductive problems such as reduced litter size, increase in the rate of return to estrous, vulvar discharge, abortion, mastitis and anestrus. Actinobaculum suis is one of the main agents involved in porcine urinary tract infection and is responsible for the most severe and fatal cases in sows. In the present report, 23 A. suis strains isolated from a sow and boars in Brazil were identified by PCR and further characterized by broth microdilution, molecular typing by pulsed-field gel electrophoresis (PFGE), single-enzyme amplified fragment length polymorphism (SE-AFLP), and whole-genome sequencing. All strains were sensitive to ceftiofur, linezolid, nitrofurantoin, quinupristin-dalfopristin and vancomycin. Ciprofloxacin, daptomycin, lincomycin, erythromycin and tylosin resistance was observed in 100% of tested strains. Tetracycline and tigecycline also presented high resistance rates (87% and 30.4%, respectively). PFGE with eight different restriction enzymes and three programs did not enable strain characterization; however, all strains were typed by SE-AFLP that clustered strains according to their origin, thus proving an effective tool for A. suis genotyping. Whole-genome sequencing and comparative analysis enabled species differentiation from closely related genus. This is the first report of genomic characterization of A. suis.

Experimental evaluation of human renal kidney stone spectra for intraoperative stone-tissue-instrument analysis using autofluorescence

The precision and safety of laser lithotripsy in the upper urinary tract is solely controlled by the surgeon. To our knowledge laser systems with integrated real-time analysis of target tissues are not available. An intelligent laser system with automated target differentiation and laser feedback control would provide tremendous improvement in patient safety and surgical precision. We evaluated the technical, medical and physical conditions for real-time analysis using fluorescence for future development of a new laser for lithotripsy. We collected data on the fluorescence spectra of 82 native human calculi covering the 8 most relevant subtypes compared to the spectra of endoscope components, the organic porcine urinary tract and pure samples of urinary stone compositions. Data analysis was performed to determine differences in sample signal intensities and emission wavelengths. All native stones showed a significant fluorescence signal compared to porcine urinary tract tissue or endoscope components. The amplitude of the fluorescence signal varied by a factor of 75. The weakest signal of stone material was 3.6-fold larger than the strongest signal of pig kidney tissue (mean ± SD 0.038 ± 0.043 vs 0.00058 ± 0.00058 arbitrary units). No fluorescence signal was observed for endoscope components. Fluorescence amplitude and spectral curve form were found to be unrelated to stone type. Our study provides essential information on the spectral differentiation of tissue, urinary stones and relevant endoscope components. The measurements indicate that differentiation by fluorescence is possible for all relevant stone types.

Aquaporin expression in the fetal porcine urinary tract changes during gestation.

The expression of aquaporins (AQPs) in the fetal porcine urinary tract and its relation to gestational age has not been established. Tissue samples from the renal pelvis, ureter, bladder and urethra were obtained from porcine fetuses. Samples were examined by RT-PCR (AQPs 1-11), QPCR (AQPs positive on RT-PCR), and immunohistochemistry. Bladder samples were additionally examined by Western blotting. RNA was extracted from 76 tissue samples obtained from 19 fetuses. Gestational age was 60 (n=11) or 100 days (n=8). PCR showed that AQP1, 3, 9 and 11 mRNA was expressed in all locations. The expression of AQP3 increased significantly at all four locations with gestational age, whereas AQP11 significantly decreased. AQP1 expression increased in the ureter, bladder and urethra. AQP9 mRNA expression increased in the urethra and bladder, but decreased in the ureter. AQP5 was expressed only in the urethra. Immunohistochemistry showed AQP1 staining in sub-urothelial vessels at all locations. Western blotting analysis confirmed increased AQP1 protein levels in bladder samples during gestation. Expression levels of AQP1, 3, 5, 9 and 11 in the urinary tract change during gestation, and further studies are needed to provide insights into normal and pathophysiological water handling mechanisms in the fetus.

Case report of urinary tract infection in sows of a commercial pig unit

In this paper, a case of urinary tract infection in sows of a commercial pig unit is presented for the first time in Greece. Within a period of one year, 21 cases of specific infection were recorded, representing 5.8% of the farrowings in the farm. The symptoms were obvious around the 3rd to 4th week post mating and were keeping on for 2 to 7 days. Anorexia, thirst, blood in the urine and subsequent death or survival with gradual loss of body condition were the main findings. A significant correlation between the number of sows that died, and the number of sows showing anorexia (p<0,05), or showing hypothermia (p<0,05) was observed. The average number of live born piglets at the last parturition compared to the respective figure during the previous parturitions was markedly reduced (p<0,05). The findings of microscopic and biochemical examination of the urine were indicative of infection, while biochemical examinations of blood samples of diseased sows have shown significantly increased urea (BUN) and creatinine levels (p<0,05). Bacteriological culture of urine samples have shown the presence of increased numbers of bacteria (>106/ml) such as Escherichia coli and Actinomyces suis in almost all ill sows. It is concluded that porcine urinary tract infections may cause serious problems for pig enterprises as may be directly correlated with reproductive performance and viability of the sows.

PD19-05 THE OPTIMAL GUIDEWIRE TYPE AND EFFECT OF PRIOR USE ON THE EASE OF URETERAL STENT INSERTION

INTRODUCTION AND OBJECTIVES: Ureteral stent insertion is a frequent procedure in endourology, with no clear consensus on the best wire type to facilitate stent insertion. Use of wires may result in deterioration of their protective coating, requiring greater force for stent insertion. The purpose of this study was to identify the effect of wire type, and prior use, upon average insertion force needed for a 6Fr ureteral stent. METHODS: Stent insertion was tested using an ex vivo porcine urinary tract model with continuous water infusion (1cc/min) to simulate urine production. For each trial, a new, soft, 6Fr Cook JJ ureteral stent was advanced over new and used 0.03800 diameter guide wires including the Glidewire (Terumo), Standard Teflon-coated wire (Cook), Superstiff wire (Cook), Sensor wire (Boston Scientific), Zip-wire (Boston Scientific), and Zebra wire (Boston Scientific). A Mark-10 digital force gauge was attached to the stent, and at a constant advancing rate of 2 rotations per second, the forces to advance the stent over the wire were calculated. 10 trials of stent insertion were randomly performed on 12 new and 12 used guide wires (total of 240 placements). RESULTS: The new Glidewire had the lowest average force required for stent advancement (0.18N). The forces for insertion of all other new wires were significantly higher; Standard (1.25N; p<0.01), Superstiff (2.03N; p<0.01), Sensor (1.87; p<0.01), Zip (0.22N; p<0.01), and Zebra (0.61; p<0.01). When comparing the average insertion force between new and used wires, the used wires required greater mean force in the Standard (2.42N vs. 1.25N; p <0.01), Superstiff (2.68N vs. 2.03N; p <0.01), and Zipwire (0.36N vs. 0.22N; p <.01), but there was no statistical difference between used and new fibers in the Glidewire (0.28N vs. 0.18N; p1⁄40.14), Sensor ( 1.66N vs. 1.87N; p1⁄40.18) and Zebra wire (0.59N vs.0.61N; p1⁄40.67). CONCLUSIONS: The Glidewire resulted in the lowest force for ureteral stent insertion. It may be used several times with no significant effect on ureteral stent insertion force due its resilient lubricious hydrophilic coating. Employing a used Standard, Superstiff and Zip-wire may result in additional stent insertion force. Knowledge of the forces required for stent insertion over various guide wires may allow surgeons to improve the ease and safety of stent placement.

1820 NEW MODIFIED TRAINING MODEL FOR UPPER URINARY TRACT ENDOSCOPY - USING PORCINE URINARY TRACT

You have accessJournal of UrologyStone Disease: SWL, Ureteroscopy or Percutaneous Stone Removal (III)1 Apr 20131820 NEW MODIFIED TRAINING MODEL FOR UPPER URINARY TRACT ENDOSCOPY - USING PORCINE URINARY TRACT Peter Liske, Volker Zimmermanns, and Sven Lahme Peter LiskePeter Liske Pforzheim, Germany More articles by this author , Volker ZimmermannsVolker Zimmermanns Pforzheim, Germany More articles by this author , and Sven LahmeSven Lahme Pforzheim, Germany More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2183AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Endourological procedures are of high significance in diagnosis and treatment of upper urinary tract diseases. In order to improve surgical skills it is advisable for the urological surgeon to perform in vitro exercises. So far just two-dimensional training models were available. A new three-dimensional training model using a porcine urinary tract allows to learn and practice endourological techniques close to reality. METHODS The transportable training model consists of a stainless steel torso covered with a neoprene cover. The relief of the retroperitoneum is imitated by a wire grating. The porcine urinary tracts are fixed by use of special granulate material. The urethra is fixed by suturing into a flexible silicone funnel to allow easy access to the urinary tract. All components are easy to clean and provide good hygienic conditions. RESULTS The elastic fixation of the urinary tract allows the use of semirigid and flexible ureterorenoscopes in conditions close to reality. It is possible to prepare the urinary tract with artificial stones to practice the use of holmium laserlithotrypsy. The training model was used successfully in many endourological workshops. So far more than 350 urologists have been trained successfully. CONCLUSIONS The newly developed and modified training model allows to learn and practice endourological techniques close to reality because of its special three-dimensional configuration and the use of porcine urinary tract. It was successfully used in education of urologists. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e748 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Peter Liske Pforzheim, Germany More articles by this author Volker Zimmermanns Pforzheim, Germany More articles by this author Sven Lahme Pforzheim, Germany More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...

105 Training of upper urinary tract endoscopy – experience with a new model using porcine urinary tract

105 Training of upper urinary tract endoscopy – experience with a new model using porcine urinary tract

Comparative analysis of antibiotic resistance and phylogenetic group patterns in human and porcine urinary tract infectious Escherichia coli

Urinary tract infections (UTIs) are one of the most common infectious diseases in humans and domestic animals such as pigs. The most frequent infectious agent in such infections is Escherichia coli. Virulence characteristics of E. coli UTI strains range from highly virulent pyelonephritis strains to relatively benign asymptomatic bacteriuria strains. Here we analyse a spectrum of porcine and human UTI E. coli strains with respect to their antibiotic resistance patterns and their phylogenetic groups, determined by multiplex PCR. The clonal profiles of the strains differed profoundly; whereas human strains predominantly belonged to clonal types B2 and D, these were not seen among the porcine strains, which all belonged to the E. coli clonal groups A and B1. Contrary to the human strains, the majority of the porcine strains were multidrug resistant. The distinct profiles of the porcine strains suggest selective pressure due to extensive antibiotic use.

Urine Derived Cells are a Potential Source for Urological Tissue Reconstruction

Contemporary approaches to tissue engineering and cell therapy for urinary tract reconstruction require invasive tissue biopsies to obtain autologous cells. However, these procedures are associated with potential complications. We determined whether the cells present in urine have characteristics of normal bladder cells and investigated their potential uses for urological reconstructive procedures. A total of 55 urine samples were collected from 15 healthy individuals and 8 patients with vesicoureteral reflux. Urine derived cells were isolated, expanded and tested for progenitor and differentiated cell specific markers using flow cytometry, immunofluorescence and Western immunoblotting. The chromosomal stability of cultured urine derived cells was determined by karyotype analysis. Clones were successfully established from primary cultures of urine derived cells. Isolated cells showed 3 phenotypes, including fully differentiated, differentiating and progenitor-like cells. Some urine derived cells stained positive for the surface markers c-Kit, SSEA4, CD105, CD73, CD91, CD133 and CD44. Two to 7 cells per 100 ml urine were multipoint progenitors that could expand extensively in culture. Single progenitor cells had the ability to differentiate into the cell lineages expressing urothelial, smooth muscle, endothelial and interstitial cell markers. The expression of lineage markers was characterized by Western blot and immunofluorescence analysis. Urine derived cells also maintained a normal karyotype after serial culture. A subpopulation of cells isolated from urine had progenitor cell features and the potential to differentiate into several bladder cell lineages. Urine derived cells could serve as an alternative cell source for urinary tract tissue engineering and reconstruction.

C-Kit receptor (CD117) in the porcine urinary tract

C-Kit positive interstitial cells of Cajal (ICC) play an important role in the regulation of the smooth muscle motility, acting as internal pacemakers to provide the slow wave activity within various luminal organs. Recently c-Kit-(CD117)-positive interstitial cells (IC) have been shown in the genitourinary tract, but systematic studies on the distribution and density of IC within the urinary tract are still lacking. Therefore the aim of the present study was to analyze systematically the localization and distribution of the c-Kit receptor in the urinary tract of the pig using immunohistochemical and molecular methods. Tissue samples were harvested from the porcine urinary tract including renal calices and pelvis, ureteropelvic junction, proximal, middle and distal ureter, ureteral orifice, fundus, and corpus of the bladder and the internal urethral orifice. Small and large intestine specimen served as controls. Immunohistochemistry (APAAP, IF) was applied on serial frozen sections using four monoclonal and polyclonal antibodies recognizing CD117. Whole mounts of the porcine upper urinary tract were prepared and investigated using conventional and confocal fluorescence microscopy followed by three-dimensional reconstruction. UV-laser microdissection and RT-PCR were applied to confirm the immunohistochemical results. CD117-immunoreactivity labeled bipolar IC and round-shaped mast cells (MC) throughout the adventitia, tunica muscularis and submucosa within the whole porcine urinary tract. While MC were found continuously in all investigated segments, a gradient of bipolar IC was evident. The whole mount preparations gave a detailed cytomorphology of IC within the various layers of the porcine urinary tract. Whole mount preparations revealed closed apposition of bi- and tripolar c-Kit positive IC parallel to the smooth muscle bundles and to veins of the tunica muscularis and adventitia. In the urothelium single CD117-positive interepithelial cells were found. The highest density of CD117-positive cells was found at the ureteropelvic junction, however the differences in between the segments were minimal. Microdissection and RT-PCR confirmed the results uncovered by immunohistochemistry. The ubiquitous distribution of IC and their close relationship to smooth muscle provides strong evidence that IC could contribute to the intrinsic pacemaker activity within the porcine (upper and lower) urinary tract. The role of the interepithelial CD117-positive cells as mechanosensors or as a precursor cell in the regeneration of the urothelium, is conceivable.

“UroMaix” Scaffolds: Novel Collagen Matrices for Application in Tissue Engineering of the Urinary Tract

Reconstruction of bladder and ureter tissue is indicated in cases of injury, stenosis, infection or tumor. Substitution by ileum, colon or pure synthetic polymers generates a variety of complications. Biohybrid tissue mimicking structural and functional attributes of the multilayered wall architecture of the urinary conduit may be the solution to current problems. This study reports on porcine urinary tract cells isolated and placed on UroMaix matrices with different degrees of cross-linking produced from highly purified type I collagen from medically approved porcine tissue. A patented procedure revealed membrane structures composed of a dense fibrous side and an open fibrous side. These scaffolds with the porcine urinary tract cells were incubated in a batch culture system for up to 14 days. Cell growth and topographical orientation were examined. Urothelial cells showed maximum attachment and a significant increase of living cells on the dense fiber layer of UroMaix-1. No attachment of urothelial cells occurred on the other prototypes. Smooth muscle cells showed similar behavior within the open fiber layer of all UroMaix matrices. Both urothelial and smooth muscle cells retained their phenotypes as demonstrated by the immunostaining of epithelial cytokeratin 18 and the smooth muscle myosin heavy chain respectively. Thus we could show that UroMaix scaffolds support the attachment and proliferation of urinary tract cells. The elastomeric properties of the collagenous matrices promise attractive applications in the tissue engineering of the urinary tract with its high mechanical demands.

EX VIVO TRAINING MODEL FOR PERCUTANEOUS RENAL SURGERY

Percutaneous endourological procedures require an advanced level of skills. To facilitate training in the proper technique, simulators are helpful. Non-biological models, useful for learning the basic steps, do not represent the clinical situation in an ideal way. Recently, we developed a porcine urinary tract model for ureteroscopy. Proceeding from this experience, we developed a further ex vivo model for training percutaneous endourological procedures. The kidney with the ureter is dissected off of the retroperitoneal organ package of freshly slaughtered pigs. It is embedded in silicon. The renal pelvis can be filled with saline to simulate hydronephrosis, stones can be implanted for percutaneous nephrolithotomy. This ex vivo model allows training of all percutaneous endourological procedures (e.g. percutaneous nephrostomy, percutaneous lithotomy, endopyelotomy). It is an ideal way to train these techniques, being superior to non-biological models in terms of “tissue feeling” for anatomic relations, and the great variety of procedures that can be trained. Nevertheless, it is readily available and inexpensive.

Ex vivo training model for percutaneous renal surgery

Percutaneous endourological procedures require an advanced level of skills. To facilitate training in the proper technique, simulators are helpful. Non-biological models, useful for learning the basic steps, do not represent the clinical situation in an ideal way. Recently, we developed a porcine urinary tract model for ureteroscopy. Proceeding from this experience, we developed a further ex vivo model for training percutaneous endourological procedures. The kidney with the ureter is dissected off of the retroperitoneal organ package of freshly slaughtered pigs. It is embedded in silicon. The renal pelvis can be filled with saline to simulate hydronephrosis, stones can be implanted for percutaneous nephrolithotomy. This ex vivo model allows training of all percutaneous endourological procedures (e.g. percutaneous nephrostomy, percutaneous lithotomy, endopyelotomy). It is an ideal way to train these techniques, being superior to non-biological models in terms of "tissue feeling" for anatomic relations, and the great variety of procedures that can be trained. Nevertheless, it is readily available and inexpensive.

Regulation by autonomic nerves of bladder neck sphincter function--mainly on inhibitory NANC nerves

This article describes current information concerning analyses of contraction and relaxation associated with electrical stimulation of efferent nerves in isolated mammalian sphincter muscles. Contractile responses of sphincters are mediated by alpha 1-adrenoceptors and muscarinic receptors stimulated by transmitters from adrenergic and cholinergic nerves, respectively, whereas those of the bladder body are almost exclusively mediated by transmitters from parasympathetic nerves. Relaxant responses to nerve stimulation are ascribed mainly to mechanisms that are sensitive and resistant to nitric oxide (NO) synthase inhibitors. Neurogenic calcitonin gene-related peptide and beta-adrenoceptor activation by neurogenic norepinephrine may also be involved in some mammals. Stimulus frequency is an important determinant to distinguish NO synthase-sensitive and -resistant components; responses at low frequencies are abolished by the enzyme inhibitors, whereas those at high frequencies are inhibited only partially. High and low frequency stimulation increases the cyclic GMP content in muscles, suggesting the involvement of neurogenic NO, although relaxation at high frequencies is only partially due to such a mechanism. From pharmacological studies so far analyzed, including ours performed with porcine urinary tract sphincters, it is concluded that NO synthase resistant-relaxation is not mediated by peptides nor compounds that open K+ channels in muscle cell membrane and stimulate beta-adrenoceptors. Contribution of NO and non-NO relaxing factor (s) in relaxant responses varies with animal species. Identification of this factor, determination of intracellular signaling processes and interaction with the NO/cyclic GMP system may give us a clue in developing new therapeutics to treat dysfunctions of the lower urinary tract sphincters.

Comparison of 2-octyl cyanoacrylate adhesive, fibrin glue, and suturing for wound closure in the porcine urinary tract

Objectives. To evaluate 2-octyl cyanoacrylate glue (OCG) for wound closure in the urinary tract and compare the ability of OCG, fibrin glue (FG), and suture to withstand physiologic and supraphysiologic stress, because the use of tissue adhesives such as OCG or FG might simplify laparoscopic surgery. Methods. Female domestic pigs (n = 22) underwent a 7.5-cm cystotomy. Of these, 8 had closure with OCG and 8 with FG (6 open and 2 laparoscopic in each group). The controls were closed with suture (n = 4) or not at all (n = 2). Postoperative catheter drainage was not used. At 2 days or 4 weeks postoperatively, the bladders were filled with saline to 200 mm Hg pressure and the cystotomy scars inspected for leakage. The excised scars were also examined histologically. Results. The 2 OCG and 2 FG pigs tested on postoperative day 2 leaked at less than 200 mm Hg. None of the 6 OCG pigs tested at 4 weeks leaked at less than 200 mm Hg, including the 2 closed laparoscopically. Of the 6 FG pigs intended for study at 4 weeks, 3 (including the 2 closed laparoscopically) died from a massive urine leak, 1 tested at 4 weeks leaked, and 2 did not leak. Thus, 4 of 6 FG pigs leaked by 4 weeks compared with none in the OCG group ( P = 0.06). The histologic examination was similar in the two groups. Conclusions. Preliminary results suggest that OCG provides enough strength to hold together a large bladder wound. In the same model, FG did not consistently provide adequate closure.

Porcine Urinary Tract as a Training Model for Ureteroscopy

Objectives: Endourological procedures as ureteroscopy require an advanced level of skills. To facilitate the training of the proper technique, simulators are helpful. Nonbiological models, useful to learn the basic steps, do not represent the clinical situation in an ideal way. We therefore looked for a biological but nevertheless easily available model. Methods: The complete urinary tract is dissected off the retroperitoneal organ package of freshly slaughtered pigs. Results: The porcine urinary tract model allows for training all aspects of diagnostic and therapeutic ureteroscopy including lithotripsy and stenting in a way which is almost identical to the clinical situation in humans. Conclusions: The porcine urinary tract model is an ideal ex vivo model. Concerning ‘tissue feeling’ and anatomic relations, it is superior to nonbiological simulators. Nevertheless, it is quite easily available and inexpensive. In training courses, we have used it with great success.

MR Imaging-guided Percutaneous Nephrostomy and Use of MR-compatible Catheters in the Nondilated Porcine Urinary Tract

To investigate technique and practicability of MR-guided percutaneous nephrostomy (MRPCN) and to test magnetic resonance (MR)-compatible catheters inside the urinary tract. In 10 healthy pigs, a percutaneous nephrostomy tube was placed into the nonobstructed pelvicaliceal system with use of exclusive MR guidance with a standard 1.5-T magnet. The urinary tract was visualized by intravenous injection of Gd-DTPA in combination with low-dose furosemide. The procedure was controlled with use of a T1-weighted turbo gradient-echo sequence in two orthogonal planes. The equipment for MRPCN included an 18-gauge MR-compatible puncture needle, a nitinol guide wire, and different 5-F MR catheters. In all 10 animals, the puncture needle was safely directed into the nondilated target calix. Slight deviations of the needle were detected on both MR image planes, which enabled immediate correction. This technique achieved a "first attempt" puncture of the targeted calix in each animal. MR images accurately demonstrated the dysprosium labelled tip of the different inserted catheters. It proved essential to inject a gadolinium-insaline solution via these catheters to preserve the endoluminal contrast enhancement as long as necessary. Balloon catheters were directed and inflated inside the ureter under exclusive MR guidance. Complications such as perforation and leakage were visualized by MR imaging. MRPCN is a promising technique for puncturing the pelvicaliceal system. The ability to successfully enter the urinary tract, even when it is nondilated, underscores the accuracy achievable with multiplanar MR imaging.

Mucinous vacuolar change of porcine urothelium induced by regional embolism or cryoablation.

Porcine urinary tract epithelium responds to systemic infections with an increase in mucin secretion that has been called "mucinous degeneration." Here we describe similar changes in calyceal, pelvic, and ureteric urothelium in pig renal tracts 14 days after local embolism and cryoablation (four kidneys) or cryoablation alone (six kidneys). Large mucin-filled vacuoles surrounded by smaller cytoplasmic vesicles were present in the affected urothelium but were rare in calyceal urothelium of normal kidneys. These mucinous vacuolar changes were proportional to the extent of renal necrosis and could be important in the pathologic responses of xenotransplanted pig kidneys.