Duplex systems

Whitten, S. M.; Wilcox, Duncan T.

doi:10.1002/pd.206

Cited by 83 publications

(97 citation statements)

References 26 publications

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“…Ectopic ureters could be associated with RD, resulting either from fetal urinary obstruction or from a primary failure of UB to fully engage intermediate mesoderm. In some cases, double-ectopic UB might form, to generate duplex ureters and kidneys (45). This story has received a novel "molecular twist," with experiments using genetically engineered mice.…”

Section: Ub Ectopia and Rdmentioning

confidence: 99%

Evolving Concepts in Human Renal Dysplasia

Woolf¹,

Price²,

Scambler³

et al. 2004

Journal of the American Society of Nephrology

153

128

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Abstract. Human renal dysplasia is a collection of disorders in which kidneys begin to form but then fail to differentiate into normal nephrons and collecting ducts. Dysplasia is the principal cause of childhood end-stage renal failure. Two main theories have been considered in its pathogenesis: A primary failure of ureteric bud activity and a disruption produced by fetal urinary flow impairment. Recent studies have documented deregulation of gene expression in human dysplasia, correlating with perturbed cell turnover and maturation. Mutations of nephrogenesis genes have been defined in multiorgan dysmorphic disorders in which renal dysplasia can feature, including Fraser, renal cysts and diabetes, and Kallmann syndromes. Here, it is possible to begin to understand the normal nephrogenic function of the wild-type proteins and understand how mutations might cause aberrant organogenesis.Congenital anomalies of the kidney and urinary tract (CAKUT) account for one third of all anomalies detected by routine fetal ultrasonography (1). A recent UK audit of childhood end-stage renal failure reported that CAKUT was the cause in~40% of 882 individuals (2). Acquired glomerulonephritis and congenital nephrotic syndromes, respectively, accounted for just 18% and 8% of cases, with other diseases being rare (nephronophthisis, 5%; cystinosis, 3%; polycystic kidney diseases [PKD], 3%). With improvements in dialysis and transplantation, a new cohort of children with severe CAKUT is surviving to adulthood (3,4). The spectrum of diseases encompassed by the term "CAKUT" is wide, including kidney anomalies such as aplasia, hypoplasia, multicystic dysplastic kidneys, ureteric anomalies such as megaureter, ureteropelvic junction obstruction, ureterovesical junction obstruction or incompetence, duplex kidneys/ureters, and anomalies of the bladder and urethra (5). Approximately half of the CAKUT cases associated with end-stage renal failure in children have patent urinary tracts, whereas the rest have obstructive nephropathy (2). The latter are mainly boys with bladder outflow obstruction (BOO) and posterior urethral valves (2,6). Some renal functional impairment may be superimposed postnatally from bacterial pyelonephritis and/or persistent urinary flow impairment causing renal atrophy and fibrosis. However, the primary "hit" in CAKUT is clearly a developmental one, and the main renal pathology is renal dysplasia (RD). In her landmark book Normal and Abnormal Development of the Kidney published in 1972 (7), Edith Potter emphasized that one must understand normal development to generate realistic hypotheses on the pathogenesis of congenital malformations. Here, we summarize normal human kidney development, using Potter's work (7) as a basis but also incorporating recent summaries (8,9).The metanephric human kidney precursor forms 28 d after fertilization when ureteric bud (UB) branches from the mesonephric duct (MD). In the next few days, renal mesenchyme (RM) condenses from intermediate mesoderm around the UB tip, or ampulla. Ultimately...

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Section: Ub Ectopia and Rdmentioning

confidence: 99%

Evolving Concepts in Human Renal Dysplasia

Woolf¹,

Price²,

Scambler³

et al. 2004

Journal of the American Society of Nephrology

153

128

View full text Add to dashboard Cite

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“…5A to D). Duplicated ureters are known to arise as a consequence of either the formation of two separate UBs from the WD (complete duplication) or premature branching (bifurcation) of a single UB (incomplete duplication) (49). Among the mutant kidneys with duplicated ureters, 38% (Ror2 Ϫ/Ϫ ) and 50% (Wnt5a Ϫ/Ϫ ) of the kidneys showed complete duplicated ureters while the remainder showed incomplete duplicated ureters.…”

Section: Ror2mentioning

confidence: 99%

Role of Wnt5a-Ror2 Signaling in Morphogenesis of the Metanephric Mesenchyme during Ureteric Budding

Nishita

Qiao

Miyamoto

et al. 2014

Molecular and Cellular Biology

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f Development of the metanephric kidney begins with the induction of a single ureteric bud (UB) on the caudal Wolffian duct (WD) in response to GDNF (glial cell line-derived neurotrophic factor) produced by the adjacent metanephric mesenchyme (MM). Mutual interaction between the UB and MM maintains expression of GDNF in the MM, thereby supporting further outgrowth and branching morphogenesis of the UB, while the MM also grows and aggregates around the branched tips of the UB. Ror2, a member of the Ror family of receptor tyrosine kinases, has been shown to act as a receptor for Wnt5a to mediate noncanonical Wnt signaling. We show that Ror2 is predominantly expressed in the MM during UB induction and that Ror2-and Wnt5a-deficient mice exhibit duplicated ureters and kidneys due to ectopic UB induction. During initial UB formation, these mutant embryos show dysregulated positioning of the MM, resulting in spatiotemporally aberrant interaction between the MM and WD, which provides the WD with inappropriate GDNF signaling. Furthermore, the numbers of proliferating cells in the mutant MM are markedly reduced compared to the wild-type MM. These results indicate an important role of Wnt5a-Ror2 signaling in morphogenesis of the MM to ensure proper epithelial tubular formation of the UB required for kidney development.

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“…If the duplex system is associated with ectopic ureter then infection, urinary retention, dribbling incontinence and abdominal mass or prolapsing ureterocele may lead to the diagnosis. 5 Voiding cystourethrography (VCUG) demonstrates reflux in about 66% of cases of complete duplication and ureterocele in 6% of completely duplicated systems. 6 Renal scarring may be assessed with either dimercaptosuccinic acid (DMSA) or mercaptoacetyltriglycine (MAG3) renal scans.…”

Section: Discussionmentioning

confidence: 99%

“…Heminephrectomy should be considered for complex duplex systems where there is increasing renal damage, failure of antibiotic prophylaxis or a poorly functioning moiety (less than 10%). 5 Neuroblastoma is a tumour of the postganglionic sympathetic neurons and is the most common extracranial solid tumour of childhood with a prevalence of about 1 case per 7000 births. 7 More than 90% of prenatally diagnosed neuroblastomas are adrenal in origin.…”

Section: Discussionmentioning

confidence: 99%

Atrophic upper pole of a duplex collecting system masquerading as suprarenal mass: a case study and literature review

Kavanagh

McAuley

Longpre

et al. 2013

CUAJ

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The growing use of maternal fetal ultrasound is leading to the discovery of an increasing number of suprarenal masses. Our experience with a cystic suprarenal mass detected on antenatal ultrasound is described. Location and radiographic features could not rule out the possibility of a cystic neuroblastoma; therefore, surgical resection of the mass was performed. Despite the absence of common radiologic characteristics, the pathology of the specimen revealed a non-functioning upper pole of a duplex kidney with complete duplication of the collecting system. Neonatal evaluation and management and the differential diagnosis are discussed.Can Urol Assoc J 2010;4(4):E94-96 Case reportA routine second trimester ultrasound examination of a 28-year-old female (gravida 2, para 1) showed a well circumscribed, hypoechoic mass on the upper pole of the right fetal kidney. The mass measured about 6 cm in its largest diameter and appeared predominantly cystic in structure. The remainder of the detailed sonographic evaluation was unremarkable and no ureterectasis or ureterocele was observed. Size, echogenecity and structure of the mass remained unchanged throughout the pregnancy on repeated scans. An uneventful vaginal delivery at 38 weeks gestational age resulted in a female child with healthy Apgar scores.Postpartum examination of the neonate was completely normal, without palpable abdominal mass or lumbosacral abnormality. Abdominal ultrasound at 3 days demonstrated that the cystic structure remained unchanged in size and appeared contiguous with the upper pole of the kidney. The perinatal period was complicated with a simple, culture-positive urinary tract infection at 4 months, which was treated with oral cephalexin. The child was followed with serial ultrasounds at 3 month intervals during her first year of life (Fig. 1). Throughout this period, the cyst was noted to increase in size by a small amount (less than 1 cm in greatest diameter), but remained unchanged in echogenicity and structure. Renal size was comparable bilaterally throughout this period.At 11 months, the child was admitted to hospital with a second culture-positive urinary tract infection and treated with intravenous ampicillin and gentamicin. An ultrasound performed during her admission suggested that the cystic structure was more likely suprarenal in origin and displacing the right kidney. Subsequent imaging with a voiding cystogram was normal. A magnetic resonance imaging (MRI) scan at this time further suggested suprarenal origin of the cyst with compression and anterior displacement of the upper pole of the right kidney (Fig. 2). Neither hydroureter nor ureterocele was observed on MRI.Based on the location and radiologic appearance of the cyst, our differential diagnosis included simple renal cyst, duplex kidney and adrenal neuroblastoma. . Due to the inability to eliminate neuroblastoma from the differential diagnosis, the patient was referred to our centre for surgical resection of the mass at 15 months. Via a flank approach, we explored the ...

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Duplex systems

Cited by 83 publications

References 26 publications

Evolving Concepts in Human Renal Dysplasia

Evolving Concepts in Human Renal Dysplasia

Role of Wnt5a-Ror2 Signaling in Morphogenesis of the Metanephric Mesenchyme during Ureteric Budding

Atrophic upper pole of a duplex collecting system masquerading as suprarenal mass: a case study and literature review

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