Investigating the flow dynamics in the obstructed and stented ureter by means of a biomimetic artificial model.

Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an artificial model of the ureter (i.e. ureter model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (?), volumetric flow rate (Q) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM

Pelvi-ureteric obstruction

In chapter 1 the history of pelvi-ureteric junction obstruction (PUJO) is described. In the past (Hippocrates and Tulp) this condition was recognized but it was not until the 17th century that the first operations were performed in order to drain the kidney or to remove stones. The first nephrectomy was described by Simon (1862). ... Zie: Summary

Discharge after acute kidney injury : recognising and managing risk

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Role of the immune system during the development of acute and chronic renal disease

PhD ThesisThe purpose of this thesis was to investigate the contribution of the inflammatory mediators Nuclear factor κB and complement during the progression of renal diseases. The first two results chapters in this thesis demonstrated a novel role for complement component 3 (C3) during the progression of chronic renal disease in the murine model of unilateral ureteric obstruction (UUO) C3 gene up-regulation and complement activation persisted throughout the course of UUO in wild type (WT) mice. In situ hybridisation showed that renal tubular epithelial cells were the primary site of C3 gene expression during early ureteric obstruction in the renal cortices of WT mice. Gene expression for transforming growth factor-beta (TGF-β) and collagen I in obstructed C3 deficient (C3-/-) mouse kidneys was significantly reduced compared with obstructed kidneys from WT mice. The decrease in TGF-β and collagen I also coincided with a significant reduction in mRNA expression for alpha-smooth muscle actin (α-SMA) as well as a significant decrease in interstitial collagen deposition. In addition to these observations, the number of infiltrating CD8+ T cells and F4/80+ macrophages counted within the cortical tubulointerstitial compartment, was significantly higher in C3-/- mice. Gene expression for the membrane-bound complement regulatory proteins complement receptor-related protein-y (crry), CD59a and decay accelerating factor 1 (DAF1) decreased in WT and C3-/- mice during the course of UUO. In particular, crry, CD59a and DAF1 mRNA expression was found to be much lower in C3-/- mice. A transition from membrane to cytoplasmic expression of crry protein was also demonstrated in tubular epithelial cells of obstructed WT mouse kidneys. In contrast to this, factor H gene expression was markedly elevated in WT mice, but not in C3-/- mice. 13 In vitro stimulation of mouse proximal tubular cells using lipopolysaccharide (LPS) resulted in complement activation, C3 gene up-regulation and production of C3 protein, providing an in vitro model to use for future targeting of proximal tubular epithelial cell C3 gene expression. The final results chapter of this thesis demonstrated an important role for nuclear factor kappa-B (NF-κB) subunit nfκb1 during the progression of renal inflammation in the nephrotoxic serum nephritis model of acute renal injury. nfκb1 deficient mice developed significantly worse glomerular injury and proteinuria and displayed sustained up-regulation of interleukin-6 and S100 calcium binding proteins A8 and A9. Finally, in contrast to observations in the nephrotoxic serum model, fibrosis, immune cell infiltration and cytokine mRNA expression were all unchanged in nfκb1 deficient mice compared with WT mice after ten days of ureteric obstruction.Northern Counties Kidney Researc

Management of ureteric endometriosis associated with hydronephrosis: An Australian case series of 13 patients

<p>Abstract</p> <p>Background</p> <p>Hydronephrosis is a rare but serious manifestation of ureteric endometriosis.</p> <p>Findings</p> <p>One hundred and twenty-six women underwent ureterolysis for ureteric endometriosis betweeen and October 1996 and June 2009. Thirteen of the 126 women were identified as having ureteric obstruction at the time of their procedure and were included in the case series. The median age was 39.5 (30 - 63). Chronic pelvic pain was the most common presenting symptom (53.8%). The point of ureteric obstruction was noted to occur most commonly at a small segment of distal left ureter, where it is crossed by the uterine artery (54%). Seven of the 13 women (53.8%) were successfully managed with ureterolysis only. Three of the 13 women (21.3%) underwent ureterolysis and placement of a double J ureteric stent. Three of the 13 (21.3%) required a segmental ureteric resection. There was one incidence of inadvertent thermal ureteric injury which was managed with a ureteric stent. In all cases the hydronephrosis had resolved at six months follow up.</p> <p>Conclusions</p> <p>Our findings support the growing body of literature supporting ureterolysis as the optimal treatment for ureteric endometriosis causing moderate to severe ureteric obstruction.</p

Functional evaluation of the urinary tract by duplex Doppler ultrasonography in patients with acute renal colic

Purpose: To determine the role of duplex Doppler ultrasonography (DDU) in Patients with acute unilateral renal obstruction. Subjects And Methods:A total of 161 Patients with suspected renal colic due to urolithiasis were evaluated by DDU followed by intravenous urography (IVU). The mean intra-arterial resistive index (RI) and the difference of mean resistive index between both kidneys (delta RI) were determined for each person. An RI value of ≥0.70 and a delta RI value of ≥0.06 were taken as the discriminatory threshold for obstruction. IVU results were considered the reference standard against which renal DDU findings were compared. Results: IVU showed both kidneys to be normal in 51 Patients and with unilateral ureteric obstruction in 110 Patients. The mean RI for obstructed kidneys was 0.67 (0.048), which was significantly higher (P-value Conclusion: Delta RI is more sensitive and specific than RI in acute renal obstruction. However, due to relatively low sensitivity for detection of partial obstruction, DDU cannot replace IVU as the standard imaging technique

Management of obstructive nephropathy in a tertiary hospital in North West Nigeria: A five-year review

Background: Obstructive nephropathy is managed initially with urinary diversion and possibly haemodialysis before definitive therapy. This study was aimed at determining the pattern of presentation, aetiology and management options of obstructive nephropathy in our practice.Methods: This was a five-year retrospective study of the patients managed for obstructive nephropathy at our facility from January 2011-December 2015. Data were collected via a pro forma and analysed using SPSS version 20.0.Results: There were 106 patients managed for obstructive nephropathy with a mean age of 48.3 ± 17. 4 years and age range of 4 months to 85 years. The male: female ratio was 10:1. The most common causes of obstructive nephropathy were bladder cancer (49.1%), benign prostatic hyperplasia (BPH, 22.6%), bilateral ureteric stone (5.7%) and bilateral schistosomal lower ureteric obstruction (4.7%). Urethral or suprapubic catheterisation (22.6%), nephrostomy (2.8%) and dialysis (10.4%) were the initial treatments. Chemoradiation was done for the patients with bladder cancer and 17.9% of the patients had operative interventions, which included ureteroneocystostomy, open prostatectomy or transurethral resection of the prostate, and ureteroscopy + lithotripsy. Fifty-two patients (49.1%) died while awaiting dialysis and four patients (3.8%) developed end-stage renal disease.Conclusions: Bladder carcinomas, BPH, ureteric obstruction are the commonest causes of obstructive nephropathy in our practice. The initial treatment includes urinary diversion and or dialysis before definitive treatment.Keywords: obstructive nephropathy; bladder cancer; acute kidney injury; chronic kidney injury; urinary diversion; dialysi

Investigating the flow dynamics in the obstructed and stented ureter by means of a biomimetic artificial model

Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an artificial model of the ureter (i.e. ureter model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (μ), volumetric flow rate (Q ) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM

Retroiliac ureter presenting as right upper ureteric obstruction – report of a rare case

Retroiliac ureter is an extremely rare urological entity in which the ureter passes deep to the iliac vessels. Congenital causes are most often secondary to vascular variants. A 39 year old lady presented with one month history of right loin pain. CECT showed right gross HUN till L3 and EC renogram showed 33% function in right kidney with obstructive pattern. RGP revealed Right Pelvic Ureteric Junction Obstruction (PUJO) obstruction, but at exploration was found to have retroiliac ureter. Ureteral division with anterior relocation and dismembered pyeloplasty was done. Anomalous vascular structures are often not diagnosed until surgical intervention for an obstruction of unknown etiology, unless vascular studies are considered, Most of these patients require surgical exploration to exclude tubercular stricture or malignant process