Acute Ureteral Obstruction Research Articles

Inguinal Bladder Hernia With Acute Ureteral Obstruction 14 Years After Kidney Transplantation: A Case Report

An 82-year-old man with a history of renal transplantation 14 years earlier presented with acute obstructive renal failure secondary to inguinal herniation of the urinary bladder complicated by ureteroneocystostomy entrapment. After percutaneous nephrostomy tube and endoscopic stent placement, the bladder was reduced and the hernia repaired with the use of a preperitoneal mesh. The postoperative course was uneventful and the renal function returned to normal. Inguinal herniation of the transplant ureter is a rare cause of hydronephrosis, but it has been described in the literature. Bladder hernias do usually not cause urologic complications in the nontransplanted patient, but they can present as an emergency after renal transplantation.

Acute bilateral ureteral obstruction following Dextranomer/hyaluronic acid polymer injection: A case report

Ureteral obstruction following bulking agent injection for treatment of vesicoureteral reflux is rare. Herein we report a case of acute bilateral ureteral obstruction following bilateral Dextranomer/hyaluronic acid polymer injection. The obstruction which manifested hours following the injection, was treated with prompt insertion of bilateral ureteral stents. The stents were removed 4 weeks later with complete resolution of the obstruction. We believe that ureteral stenting is an excellent solution for acute ureteral obstruction following Dextranomer/hyaluronic acid polymer injection.

Low pressure ureteroscope in treatment of acute ureteral obstruction associated with infection

Objectives To explore the feasibility of low pressure technology in the treatment of ureteral calculus obstruction with serious infection. Methods 28 cases of patients with ureteral calculi associated with acute infection of first phase placed F5 double-J tube under ureteroscopy. F5 double-J tube was retained, F8 urine tube was indwelled in phase II and low perfusion pressure was used in small ureteroscopic holmium laser lithotripsy. Results 28 cases of ureteroscopies were performed successfully. 23 cases retained double-J tube during the operation, 5 cases did not retained the double-J tube. In the two groups, 2 cases had fever after operation, stones returned within the kidney in one case. All patients recovered renal function with different degree without residual stones after 3 months. Conclusions F5 double-J tube was retained under ureteroscopy in first phase and in phase II, F8 urine tube was indwelled and low perfusion pressure was used in small ureteroscopic holmium laser lithotripsy is the effective treatment of acute ureteral obstruction associated with infection. Key words: Ureteral Obstruction; Ureteroscopes; Infection

Nitric oxide and asymmetric dimethyl arginine (ADMA) levels in an experimental hydronephrotic kidney caused by unilateral partial ureteral obstruction.

ABSTRACTAim Our aim is to measure asymmetric dimethyl arginine and nitric oxide levels in rats with induced unilateral acute ureteral obstruction to research the effects on the kidney.Material and Methods The study included 21 adolescent (average age 6 weeks) Sprague-Dawley male rats weighing between 240-290g divided at random into 3 groups. Group-1: Control group (n=6): underwent no procedures. Group-2: Sham group (n=6): underwent the same procedures as the experimental group without ureter and psoas muscle dissection. Group-3: Group with induced partial unilateral ureteral obstruction (n=9). All rats were sacrificed after 12 weeks. Superoxide dismutase enzyme activity and nitrite and nitrate salt levels were measured in renal tissue. Plasma nitrite-nitrate and ADMA levels were examined.Results In the experimental group histopathological changes observed included renal pelvis dilatation, flattened papillae, sclerotic glomerulus and fibrosis. In the experimental group tissue SOD and blood ADMA levels were higher than the control and sham groups (p<0.05) while tissue NO and plasma NO values were lower than in the sham and control groups (p<0.05).Conclusion Oxidative stress and disruption of NO synthesis play an important role in renal function and histopathological changes after obstructive renal disease. To prevent renal complications developing after obstructive nephropathy we believe that a new strategy may be research on reducing ADMA.

Use of Phenazopyridine in Visualizing Ureteral Jet Stream During Cystoscopy [28A

INTRODUCTION: Cystoscopy is an important for evaluation of potential lower urinary tract injuries including urethral and bladder injury following gynecologic surgery. In such times when evaluation of the lower urinary tract is indicated; previously, patients were previously given indigo carmine to assist in the evaluation of ureteral jet flow. There is a void in safe, available options to assist with evaluation of the ureteral jet flow. The use of phenazopyridine could be an alternative. METHODS: Patients reviewed from the Sacred Heart Hospital Medical Oncology Group in Pensacola, Florida from October 1, 2014 to March 31, 2015. Patients were included in this study if the operative report indicated that cystoscopy was performed with documented oral phenazopyridine 200 mg given. The primary outcome was to identify if phenazopyridine aided in identifying the ureteral jet stream. RESULTS: A total of 241 patients had surgery. Of the 241 charts reviewed, 112 patients had cystoscopy performed with administration of phenazopyridine and documentation of cystoscopy findings. Phenazopyridine-stained urine with bilateral ureteral efflux was documented in 94 charts. Bilateral ureteral efflux without mention of phenazopyridine-stained urine was documented in 11%. In 6 charts, phenazopyridine was given preoperatively but was specified as not being seen. CONCLUSION: Studies have shown that routine use of cystoscopy in gynecologic surgeries can improve earlier detection of lower urinary tract injuries, which can prevent morbidity and long-term sequelae. It's more reliable in diagnosis of acute ureteral obstruction. The use of phenazopyridine is both safe and useful for visualization of the ureteral jet streams during intra-operative cystoscopy.

MP58-14 NEUTROPHIL GELATINASE-ASSOCIATED LIPOCALIN (NGAL) AS A BIOMARKER OF RENAL INJURY IN PATIENTS WITH URETERIC STONES

You have accessJournal of UrologyStone Disease: Basic Research & Pathophysiology I1 Apr 2016MP58-14 NEUTROPHIL GELATINASE-ASSOCIATED LIPOCALIN (NGAL) AS A BIOMARKER OF RENAL INJURY IN PATIENTS WITH URETERIC STONES Marco Bolgeri, Khaled Farrag, Antonio Reche, Padmini Manghat, and Seshadri Sriprasad Marco BolgeriMarco Bolgeri More articles by this author , Khaled FarragKhaled Farrag More articles by this author , Antonio RecheAntonio Reche More articles by this author , Padmini ManghatPadmini Manghat More articles by this author , and Seshadri SriprasadSeshadri Sriprasad More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.812AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES An accurate assessment of the risk of renal injury in the patient presenting with renal colic is challenging. Creatinine and urine output measurement have significant pitfalls in patients with normal contralateral kidneys. A biomarker of renal injury may offer the opportunity for early detection and aid clinical management. NGAL has shown good performance in the prediction of renal injury in several clinical scenarios. Our objective was to analyze the kinetics of NGAL in patients presenting with acute ureteric obstruction secondary to stone. METHODS Serum (sNGAL) and urine (uNGAL, normalized to urinary creatinine) levels were measured pre-, intra- and postoperatively in 37 subjects with acute ureteric colic, and compared with two control groups (13 patients with non-obstructive renal stones undergoing elective surgery and 10 healthy controls). Samples were analyzed with the NGAL Test (Bioporto Diagnostics, Denmark) a commercially available particle-enhanced turbidometric immunoassay. Uni- and multivariate analyses were conducted to evaluate correlation of NGAL levels with commonly adopted clinical parameters. RESULTS Levels of sNGAL decreased significantly after relief of ureteric obstruction (77ng/mL vs 82ng/mL, p=0.01), whereas uNGAL increased. uNGAL levels in the urine from the obstructed kidney were significantly higher than in the bladder (p=0.003). In patients who passed their stone, at a median 4 weeks follow-up NGAL levels were significantly lower (p=0.03). NGAL levels at presentation were significantly lower in healthy controls (p=0.003). In controls undergoing elective surgery, pre- and post-operative levels of pNGAL and uNGAL were not significantly different (p=0.61 and p=0.09) On multivariate analysis female gender and a higher white cell count were the only factors correlated with higher NGAL levels. CONCLUSIONS To our knowledge this is the first study evaluating the kinetics of NGAL at different time points in patients with obstruction due to ureteric stones. Relief of obstruction led to a significant decrease in sNGAL levels, though with a brief increase in urinary levels due to release of NGAL-rich urine from the obstructed side. Surgical intervention did not act as a confounder. These observations suggest that this biomarker could help estimating renal injury due to obstructive stones and help as a marker of de-obstruction during follow-up. Further studies are needed to establish the long-term significance of such subclinical renal injury and better define the potential role of NGAL in the clinical decision-making. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e781-e782 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Marco Bolgeri More articles by this author Khaled Farrag More articles by this author Antonio Reche More articles by this author Padmini Manghat More articles by this author Seshadri Sriprasad More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Perioperative morbidity and long-term outcome of unilateral nephrectomy in feline kidney donors: 141 cases (1998-2013).

OBJECTIVE To evaluate the outcome associated with unilateral nephrectomy in feline kidney donors. DESIGN Retrospective case series. ANIMALS 141 cats. PROCEDURES Medical records of cats that underwent nephrectomy for renal donation were reviewed for information on signalment, date of renal donation, results of blood and urine analyses, infectious disease history, anesthetic protocols, intra- and postoperative complications, and postoperative analgesic protocols. Long-term follow-up data were obtained via client telephone interview and review of referring veterinarian medical records. RESULTS All donors were healthy young adult cats with a median age of 1.5 years (range, 0.8 to 2 years). No cats died or were euthanized during the perioperative period. Intraoperative complications occurred in 2 cats, and postoperative complications occurred in 17. Median time from nephrectomy to hospital discharge was 3.6 days (range, 2 to 8 days). Long-term follow-up information was available for 99 cats, with a median interval between nephrectomy and follow-up of 10 years (range, 0.25 to 15 years). Six cats had a history of urinary tract disease including stable chronic kidney disease (n = 3), acute kidney injury (2), and cystitis (1). Nine cats were dead at follow-up; death was attributed to chronic renal failure in 2 and acute ureteral obstruction in 4. CONCLUSIONS AND CLINICAL RELEVANCE Feline donor nephrectomy had an acceptably low perioperative morbidity in this series. Most cats (84%) for which follow-up information was available had no associated long-term effects. However, a small subset (7%) developed renal insufficiency or died of urinary tract disease.

73 Acute unilateral ureteric obstruction with high serum creatinine. Is it true or false renal impairment?

73 Acute unilateral ureteric obstruction with high serum creatinine. Is it true or false renal impairment?

CT-based assessment of renal function impairment in patients with acute unilateral ureteral obstruction by urinary stones.

The purpose of our study was to evaluate computed tomography (CT) imaging factors related to renal function impairment in patients with acute unilateral ureteral obstruction by urinary stones. The study included 94 patients who had acute unilateral ureteral obstruction due to a urinary stone and a normal contralateral kidney. We retrospectively investigated the serum creatinine (SCr) levels immediately prior to CT examination and at least 1week after treatment. CT examinations were performed using a CT urography protocol, including pre- and post-contrast images. The 67 patients with a SCr change of less than 0.3mg/dL constituted group A. The other 27 patients with a SCr decrease of more than 0.3mg/dL constituted group B. To evaluate factors related to renal function impairment, differences in CT imaging factors between the two groups, including the cortical and medullary density, renal and pelvic anteroposterior diameter, and perinephric fluid, were statistically analyzed. The SCr immediately prior to CT examination significantly differed between the two groups. The follow-up SCr after resolution did not significantly differ between the two groups. The difference in the mean cortical and medullary HU on the nephrographic phase between the obstructed kidney and normal kidney was higher in group B than in group A (27.1±23.1 and 69.4±59.1 vs. 5.7±8.8 and 31.8±34.8; p<0.001 and p=0.004, respectively). The cut-off point for the difference in the mean cortical HU on the nephrographic phase between the obstructed kidney and normal kidney for renal function impairment was 15 HU, as determined by a receiver operating characteristic curve analysis. Patients with significantly impaired renal function due to an acute unilateral ureteral obstruction may show a decreased nephrogram of the affected kidney and a significant difference in the HU on the nephrographic phase between the obstructed and normal kidney.

Quercetin attenuates cyclooxygenase-2 expression in response to acute ureteral obstruction

Unilateral ureteral obstruction (UUO) is associated with increased hydrostatic pressure, inflammation, and oxidative stress in the renal parenchyma. Previous studies have demonstrated marked cyclooxygenase (COX)-2 induction in renal medullary interstitial cells (RMICs) in response to UUO. The aim of the present study was to evaluate the effect of quercetin, a naturally occurring antioxidant, on COX-2 induction in vivo and in vitro. Rats subjected to 24 h of UUO were treated intraperitoneally with quercetin (50 mg·kg(-1)·day(-1)). Quercetin partly prevented COX-2 induction in the renal inner medulla in response to UUO. Moreover, RMICs exposed to conditions associated with obstruction, inflammation (produced by IL-1β), oxidative stress (produced by H2O2), and mechanical stress (produced by stretch) showed increased COX-2 expression. Interestingly, quercetin reduced COX-2 induction in RMICs subjected to stretched. Similarly, PGE2 production was markedly increased in RMICs exposed to stretch and was reversed to control levels by quercetin treatment. Furthermore, stretch-induced phosphorylation of ERK1/2 was blocked by quercetin, and inhibition of ERK1/2 attenuated stretch-induced COX-2 induction in RMICs. These results indicate that quercetin attenuated the induction of COX-2 expression and activity in RMICs exposed to mechanical stress as a consequence of acute UUO and that the MAPK ERK1/2 pathway might be involved in this quercetin-mediated reduction in COX-2.

Intrarenal Doppler indices in acute ureteric obstruction.

Urolithiasis remains a major health problem despite advances in therapy. Obstruction results in an increase in pressure within the urinary tract, causing structural and physiologic changes. This study aimed to calculate the intra renal Resistivity Index (RI) of acutely obstructed kidney, to determine the significance of Resistivity Index Ratio (RIR) and difference in Resistivity Index of obstructed and contralateral non obstructed kidney. Prospective study with renal Doppler for patients presenting with acute unilateral ureteric obstruction. Seventy two patients between the age group 20-45 y presenting to the Department of Radiodiagnosis, between January - December 2006 with acute unilateral ureteric obstruction were included in the study. Gray scale and Doppler evaluation of the kidneys done; with assessment of the ureteric calculus. Renal Doppler indices calculated and follow up of the same done after relief of obstruction. Statistical analysis was done using SPSS Software V13 and p-value <0.05 was considered as statistically significant. Forty two patients (58.33%) had mild, 28 (38.89%) moderate and 2 (2.78%) severe hydronephrosis. The mean RI of the obstructed kidney was 0.66±0.88 and that of contralateral non obstructed kidney was 0.569±0.05. Delta RI between the obstructed and contralateral non obstructed kidney was 0.08±0.03. The mean RIR between the obstructed and non obstructed kidney was 1.12±0.04 and the same after relief of obstruction was 1.03±0.06. The intrarenal Resistivity indices are less sensitive indicators in predicting the diagnosis of acute ureteric obstruction, although Resistivity Index Ratio appears to be a better parameter. The indices within the normal range do not rule out the absence of obstruction. Hence these parameters should not be interpreted in isolation.

Changes in phosphorylated heat‐shock protein 27 in response to acute ureteral obstruction in rats

In vivo, renal medullary interstitial cells (RMICs) and collecting duct principal cells (mpkCCD cells) are subjected to inflammatory, oxidative and mechanical stress as a result of unilateral ureteral obstruction (UUO). Because heat-shock protein (HSP) 27 and HSP70 are induced by cellular stresses and play a role in cytoprotection, we hypothesized that HSP27 and HSP70 are increased in rats subjected to acute UUO and in RMICs and mpkCCD cells exposed to inflammatory, oxidative or mechanical stress. Rats were subjected to acute UUO for 6 h and 12 h. To examine the expression of HSP27, phosphorylated HSP27 (pHSP27) and HSP70 in response to inflammatory, oxidative and mechanical stress in vitro, we exposed RMICs and mpkCCD cells to interleukin 1β (IL-1β), hydrogen peroxide (H2 O2 ), and stretch stimulation over time. The phosphorylated form of HSP27 (pHSP27) was increased in the renal inner medulla (IM) after 6-h and 12-h UUO, while HSP27 and HSP70 were unchanged. Furthermore, after 6 h and 12 h of UUO, the expression of inflammatory (IL-1β) and oxidative [haem oxygenase 1 (HO-1)] markers was induced. Exposure to inflammatory, oxidative and mechanical stress changed HSP27 and pHSP27 expression in RMICs but not in mpkCCD cells, while HSP70 was not affected by any of the stress conditions. Exposure of RMICs to oxidative and mechanical stress induced HSP27 phosphorylation via a p38-dependent mechanism. These data demonstrate that, in response to acute UUO, different forms of cellular stresses modulate HSP27 expression and phosphorylation in RMICs. This may affect the ability of renal cells to mount an effective cytoprotective response.

Pre- or post-treatment with aminoguanidine attenuates a renal distal acidification defect induced by acute ureteral obstruction in rats

Acute unilateral ureteral obstruction (UUO) impairs distal nephron acid secretion and stimulates expression of inducible nitric oxide synthase (iNOS) in post-obstructed kidney (POK). This study investigated the influence of pre- or post-treatment with aminoguanidine as a selective iNOS inhibitor on UUO-induced renal functional disturbances. To induce acute UUO, the left ureter in rats was ligated and released after 24 h. Then, a 3 h clearance period followed by bicarbonate loading and thereafter a 30 min clearance period were allocated. Aminoguanidine was administered either prior to the UUO induction or after release of the obstruction in the different rat groups, while untreated and sham groups received normal saline. During the first clearance period, fractional bicarbonate excretion and urinary pH increased markedly in the POK of the untreated group compared with the left kidney of sham group, and a large drop in the difference between urine and blood pCO2 (U-B pCO2) was observed after bicarbonate loading; all of these parameters were ameliorated in the pre-treated and post-treated groups. However, the UUO-induced decreases in creatinine clearance, sodium reabsorption, urine osmolality, and free-water reabsorption in the POK were attenuated only in the post-treated group. Therefore, the in vivo application of a selective iNOS inhibitor partially improved the acute UUO-induced distal nephron acidification defect, while post-treatment but not pre-treatment with aminoguanidine ameliorated decrements of glomerular filtration, sodium reabsorption, and urine-concentrating ability.

The importance of renal Doppler ultrasonographic evaluation in acute ureteral obstruction in pregnant women

I read the article by Dr. Pepe and associate with interest [1]. They evaluated 234 pregnant women asymptomatic in 204 cases and with unilateral renal colic in 30 by duplex Doppler and conventional Ultrasonography to detect possible renal/ureteral pathology. The mean intra-arterial resistive index (RI) and the difference of mean resistive index between both kidneys (delta RI) were measured from interlobar arteries as we did in our study published recently [2]. A renal RI [ 0.70 and/or a 10 % difference between the kidneys were considered as diagnostic of obstructive uropathy. The detected mean RI for obstructed kidneys was significantly higher than a mean RI of contralateral normal kidneys. Accordingly, we were interested in the changes in renal Doppler ultrasonographic parameters in patients managed with rigid ureteroscopy [2]. In urology practice, during a ureteroscopic operation, because of the irrigation fluid used, the irrigation pressures generated within the collecting system can be elevated, and can cause pyelovenous and pyelolymphatic backflow. This backflow may create a pressure on intrarenal vasculature and may also contribute to the increase in renal vascular resistance. Amount of the irrigation pressures transmitted to the renal pelvis, collecting ducts and subsequently to the parenchyma determine the degree of the vasoconstrictive response that would eventually lead to an increase in RI values. As we hypothesized, RI and delta RI values of the operated kidneys were found to be significantly greater than the values for non-operated kidneys. Delta RI was regarded as the mean difference between the postoperative and preoperative RI values in the same kidney. In contrast, in the study by Pepe et al., the difference in mean RI of the obstructed and contralateral kidneys was accepted as delta RI. In anyway, both studies reveal the importance of RI measurements in obstructed cases. In current clinical practice, Doppler ultrasonographic measurements and relevant RI values are not regarded as the primary diagnostic modalities in the functional evaluation of the urinary tract. If we accept ureteroscopic investigation somehow a simulation of a ureteral obstruction, in all suspected ureteral/ renal obstructions (whatever the cause is), evaluation via Doppler ultrasonography may guide the clinician to determine the obstructive degree of renal units. With the calculation of delta RI, increase in RI values in renal units when compared to contralateral ones should be determined, thereby the amount of obstructive stress/pressure on diseased kidney might be suspected. In clinical perspective, by this way, the clinician can have an idea of the obstructive degree of a certain pathology. Hence, treatment options would more readily and correctly be decided. For example, a ureteral stone in a pregnant woman might be treated with conservative medical expulsive therapy if delta RI is low, or it may be eliminated by endoscopic surgery within a short period of time if delta RI is high. Difficulty in determining a certain threshold value for delta RI remains a problematic issue, since delta RI values range just between 0.00 and 0.10 as in our study. Percent calculations, as Dr. Pepe preferred (10 % RI difference between kidneys), can rather be more suggestive and discriminative. In conclusion, we advice delta RI measurements in acute renal colic to determine the degree of obstructive stress on O. Tokgoz (&) Department of Radiology, School of Medicine, Bulent Ecevit University, Hastanesi S-Blok Kat:4, Kozlu, Zonguldak 67600, Turkey e-mail: h_tokgoz@hotmail.com

Intrarenal urothelial transformation after obstruction: a novel metaplasia

Obstructive nephropathy is a major cause of acute renal failure and end-stage renal disease. We discuss the new findings of Girshovich et al., who show that transformation of intrarenal urothelium into a bladder-like urothelium depends on the activation of the FGF7-FGFR2 signaling pathway following acute ureteral obstruction. A possible link between hypoxia-inducible factor 1α and the FGF-FGFR signaling pathway is suggested.

Initial experience with a newly developed antirefluxive ureter stent

The objective of this study was to assess the functional efficacy of newly developed antirefluxive ureter stents (DJ), by performing immediate post-stenting cystograms on patients with acute ureteral obstruction requiring a DJ stent, and assessing stent-related symptoms by means of ureteral stent symptoms questionnaire (USSQ). Patients with acute hydronephrosis requiring internal drainage were randomized to receive either an antirefluxive DJ or a conventional DJ (7 Fr., 26 cm, polyurethane, Urovision(®), Germany). Mean stone size was 6.64 ± 3.33 and 6.5 ± 3.54 mm. Immediately after correct placement of the DJ, 200 ml of diluted contrast media was introduced into the bladder under fluoroscopic control to detect vesicoureteral reflux (VUR). Patients completed German versions of the USSQ on days 2 and 7 following stent placement, and 1 week after stent removal. The results were analyzed. 13 conventional and 16 antirefluxive stents were placed in 29 patients. Reflux was documented in eight conventionally stented patients (62.5%). Two of the 16 patients with antirefluxive stents (22%) presented reflux. 1 week after stent implantation, the mean pain value was 1.1 in the antirefluxive group and 3 in the standard group (p < 0.062). Flank pain during micturition occurred after 2 days in seven patients (58%) with standard stents and in three patients (33%) with antirefluxive stents (p < 0.23). 1 week after stent insertion, flank pain had dropped to 40% in the standard group and 11% in the antirefluxive group (p < 0.3). Our initial experience showed that the antirefluxive system might be effective in terms of reflux prevention and reduction of stent related symptoms especially during sexual intercourse.

The effect of nitric oxide on the pressure of the acutely obstructed ureter

Acute ureteral obstruction leads to changes in pressure inside the ureter, interrupting ureter function. The aim of our study is to explore the relationship between nitric oxide (NO) concentration and pressure in the ureter and to observe the effects of nitric oxide on the revival of renal function. We created the animal models by embedding balloons in the lower ureters of anesthetized dogs and expanding them to simulate acute ureteral obstruction. First, the test animals were pre-treated intravenously with different doses of L-NAME (non-selective nitric oxide synthase inhibitor) to inhibit nitric oxide synthase (NOS), and 10 min later, each subject was administered an intravenous dose of isoproterenol (10 μg/kg). We measured ureter pressure (UP), total and peak concentrations of NO (using an NO monitor, model inNO-T) in ureteral urine, and the volume of the urine (UFV) leaking from the balloon edge. After a certain amount of time had elapsed, it became clear that the dose of L-NAME was inversely related to the total and peak concentrations of NO, the rate of change in UP, and the volume of urine produced. We conclude that L-NAME prevents the NOS from inhibiting the release of NO, then inhibits the effect of isoproterenol reducing the pressure of the acute obstructive ureter. Inversely, we think that NO can reduce the pressure of the acute obstructive ureter and make the obstructive ureter recanalization. And when more the concentration of nitric oxide, the more the pressure will be reduced, and more urine will be collected.

Diffusion-weighted MR Imaging of Native and Transplanted Kidneys

Applications of diffusion-weighted (DW) magnetic resonance (MR) imaging outside the brain have gained increasing importance in recent years. Owing to technical improvements in MR imaging units and faster sequences, the need for noninvasive imaging without contrast medium administration, mainly in patients with renal insufficiency, can be met successfully by applying this technique. DW MR imaging is quantified by the apparent diffusion coefficient (ADC), which provides information on diffusion and perfusion simultaneously. By using a biexponential fitting process of the DW MR imaging data, these two entities can be separated, because this type of fitting process can serve as an estimate of both the perfusion fraction and the true diffusion coefficient. DW MR imaging can be applied for functional evaluation of the kidneys in patients with acute or chronic renal failure. Impairment of renal function is accompanied by a decreased ADC. Acute ureteral obstruction leads to perfusion and diffusion changes in the affected kidney, and renal artery stenosis results in a decreased ADC. In patients with pyelonephritis, diffuse or focal changes in signal intensity are seen on the high-b-value images, with increased signal intensity corresponding to low signal intensity on the ADC map. The feasibility and reproducibility of DW MR imaging in patients with transplanted kidneys have already been demonstrated, and initial results seem to be promising for the assessment of allograft deterioration. Overall, performance of renal DW MR imaging, presuming that measurements are of high quality, will further boost this modality, particularly for early detection of diffuse renal conditions, as well as more accurate characterization of focal renal lesions.

Ureteral Selectivity of Intravenous β-Adrenoceptor Agonists in Pig Model of Acute Ureteral Obstruction: Comparison of KUL-7211, a Selective β 2/β 3 Agonist, With Isoproterenol, Terbutaline, and CL-316243

To compare the potency and ureteral selectivity of the selective β(2)/β(3)-adrenoceptor agonist KUL-7211 with those of the nonselective β-adrenoceptor agonist isoproterenol, selective β(2)-adrenoceptor agonist terbutaline, and selective β(3)-adrenoceptor agonist CL-316243, we performed the study using an isolated porcine ureter and a porcine model of acute unilateral ureteral obstruction. The effects of the drugs on the 80-mM KCl-induced contraction of the ureteral segments isolated from male pigs were evaluated using a functional experimental technique. Anesthetized male miniature pigs with complete obstruction of the left lower ureter were used to evaluate the effects of the cumulative intravenous drug administration on the elevated intraureteral pressure and mean blood pressure. The KCl-induced contractions in the isolated ureter were concentration-dependently attenuated by KUL-7211, isoproterenol, terbutaline, and CL-316243, with a rank order of potency of 6.26, 6.98, 5.41, and 5.41, respectively. In the anesthetized pigs, all 4 drugs reduced the unilateral ureteral obstruction-induced elevated intraureteral pressure in a dose-dependent manner, with KUL-7211 reducing it with a lower hypotensive effect than either isoproterenol or terbutaline. The ureteral selectivity (defined as the ratio of the effective dose to decrease the mean blood pressure by 25% to the effective dose to decrease the intraureteral pressure by 50%) of KUL-7211 (1.5) was significantly greater than that of isoproterenol (0.04) or terbutaline (0.43). The present results have demonstrated that in pigs, KUL-7211 is a potent ureteral relaxant with a relatively small hypotensive effect. A selective β(2)/β(3)-adrenoceptor agonist, such as KUL-7211, warrants additional investigation as a potentially useful drug for the promotion of stone passage in patients with urolithiasis.

L‐carnitine improves oxidative stress and suppressed energy metabolism but not renal dysfunction following release of acute unilateral ureteral obstruction in rat

We recently showed that L-carnitine reduced oxidative stress and suppressed energy metabolism, while α-tocopherol only prevented redox imbalance, in the obstructed kidney of rats subjected to 24-hr of unilateral ureteral obstruction (UUO). The present study was undertaken to investigate the effects of both compounds on disturbed renal hemodynamics, solutes-excretion, and urine-concentrating ability as well as renal oxidative stress and suppressed metabolism at early hours following release of 24-hr UUO. UUO was induced in anaesthetized rats that received L-carnitine, α-tocopherol or their vehicles in four different groups. Each rat was re-anaesthetized, prepared for renal functional measurements, and its ureteral obstruction was released at 24-hr. Then, urines of both kidneys were separately collected during 30-90 min of post-release, with taking blood samples at beginning and end of it. Finally, both kidneys were removed and preserved at -80°C for future measuring their levels of ATP and ADP as well as malondialdehyde (MDA) and ferric reducing/antioxidant power (FRAP). There were also sham and control groups. Post-obstructed kidney (POK) of vehicle-treated groups compared to equivalent kidney of sham group had lower ATP, ATP/ADP, FRAP, creatinine clearance, absolute Na(+)- and K(+)-excretion, and effective free-water reabsorption, but higher MDA and ADP. L-carnitine could improve oxidative stress and suppressed energy metabolism and α-tocopherol normalized redox state, but both compounds did not have any effects on altered functional variables of the POK. Oxidative stress and suppressed energy metabolism may not be involved in the development of renal dysfunction during acute ureteral obstruction.