[Special diagnostics in pediatric urology-Ultrasound, VCUG, CT and MRI : Part 1: tips for the practice]. / Spezielle Diagnostik in der Kinderurologie ­ konventionelle und spezielle Sonographie, MCU, CT und MRT : Teil 1: Tipps für die Praxis.

The diagnostics and treatment of pediatric urology patients in the clinical routine can be extremely challenging. In comparison to adult patients, congenital diseases, more time consuming examinations and limited options in addition to the parents' expectations must be taken into account in the diagnostic work up. In this first of two parts we will delve into ultrasound diagnostics as the cornerstone in the diagnostic pathway of children with hydronephrosis ans take a closer look on contrast enhanced ultrasound (CEUS). Conventional voiding cystourethrography still plays a major role in the diagnostic pathway of vesicoureteric reflux and will be treated in this article. Computed tomography should only be considered in pediatric patients in rare cases, always taking radiation into critical account. Magnetic resonance imaging provides an excellent anatomical overview without exposing the child to unnecessary radiation. This article provides an overview on the diagnostic imaging studies in pediatric urology and brings tips for the diagnostic evaluation.

Establishment of a Pediatric Surgical Unit at a University Hospital in Eastern Africa.

INTRODUCTION: Ethiopia is a rapidly developing country in Eastern Africa. In total, 43.2% of the population are younger than 15. In contrast, until a few years ago, pediatric surgery was only available in Addis Ababa. Now, Ethiopia is making great efforts to improve the care of children who require surgery. JimmaChild was established to set up a pediatric surgery in Jimma. MATERIAL AND METHODS: JimmaChild developed from a scientific collaboration between Jimma University (JU) and Ludwig-Maximilians-University. The project was developed and realized by Ethiopian and German colleagues. A curriculum was written for this purpose. The pediatric surgical training of the fellows was carried out on-site by German pediatric surgeons. RESULTS: A new pediatric surgery was established at JU with its own operating room, ward, and staff. After two and a half years, two fellows completed their final examinations as pediatric surgeons. Among others, 850 elective surgeries were performed, 82% assisted by the German colleagues. The German colleagues rated the preparation for the trip, the on-site support, and the professional progress of the fellows mostly as good to very good. Reported problems in the program flow were also recognized and solved in part. CONCLUSIONS: The best possible integration of the project into existing structures was achieved by close cooperation of Ethiopian and German colleagues during the project development. Problems were identified and addressed early on by external monitoring. As the project responsibility was mainly with the Ethiopian colleagues, a department was created that now exists independently of external funding and trains its own fellows.

A combined clinical and biological risk classification improves prediction of outcome in hepatoblastoma patients.

AIM: Stratification of hepatoblastoma (HB) patients is based on clinical and imaging characteristics obtained at the time of diagnosis. We aim to integrate biomarkers into a tool that accurately predicts survival of HB patients. METHODS: We retrospectively analysed 174 HB patients for the presence of four biomarkers and explored their prognostic potential by correlating with overall survival (OS) and event-free survival (EFS). RESULTS: Mutations of CTNNB1, NFE2L2 and TERT were found in 135 (78%), 10 (6%) and 10 (6%) patients, respectively, and the adverse C2 subtype of the 16-gene signature in 63 (36%) patients. C2-patients had more frequent metastatic disease, higher alpha-fetoprotein levels, non-fetal histology and significantly worse 3-year OS (68% versus 95%) and EFS (63% versus 87%) than C1-patients. Patients carrying a NFE2L2 mutation had a significantly worse 3-year OS (57% versus 88%) than NFE2L2 wild-type patients and were more likely to have vessel invasive growth and non-fetal histology. TERT mutations were almost exclusively found in older patients, whereas CTNNB1 mutations showed no association with any clinical feature or outcome. In a multivariable analysis, the C2 subtype remained a significant predictor of poor outcome with hazard ratios of 6.202 and 3.611 for OS and EFS, respectively. When added to the Children's Hepatic tumors International Collaboration risk stratification, the presence of the C2 subtype identified a group of high-risk patients with a very poor outcome. CONCLUSION: We propose a new stratification system based on the combination of clinical factors and the 16-gene signature, which may facilitate a risk-adapted management of HB patients.

Targeting excessive MYCN expression using MLN8237 and JQ1 impairs the growth of hepatoblastoma cells.

Hepatoblastoma (HB) is the most common liver tumor in children under the age of 3 years worldwide. While many patients achieve good outcomes with surgical resection and conventional chemotherapy, there is still a high­risk population that exhibits a poor treatment response and unfavorable prognosis, which warrants the search for novel treatment options. In recent years, it has become clear that genetic events alone are not sufficient to explain the aggressive phenotype of this embryonal malignancy. Instead, epigenetic modifications and aberrant gene expression seem to be key drivers of HB. In the present study, expression analyses such as reverse transcription­quantitative polymerase chain reaction revealed that the oncogene, MYCN proto­oncogene basic­helix­loop­helix transcription factor (MYCN) was upregulated in HB and other pediatric liver tumors, due to the transcriptional activity of its antisense transcript MYCN opposite strand (MYCNOS). Pyrosequencing demonstrated the hypomethylated regions in the promoter of MYCN and MYCNOS, suggesting that an epigenetic mechanism may underlie the induction of aberrant expression. Transient MYCN knockdown in HB cells resulted in growth inhibition over time. In addition, treating HB cells with the MYCN inhibitors JQ1 and MLN8237 led to the significant downregulation of MYCN either at the mRNA or protein levels, respectively. The underlying mechanism of action of the two inhibitors was revealed to be associated with the induction of dose­dependent growth arrest, by arresting cells at either the G1/G0 or G2 phase. Furthermore, MLN8237 and JQ1 were able to cause spindle disturbances and/or apoptosis in HB cells. The present results suggest that MYCN may be a promising biomarker for HB and a potential therapeutic target in patients with tumors overexpressing MYCN.

Truncated neurokinin-1 receptor is an ubiquitous antitumor target in hepatoblastoma, and its expression is independent of tumor biology and stage.

The substance P (SP; also known as TAC1)/neurokinin-1 receptor (NK1R; also known as TACR1) complex is a critical part in the development of cancer. Therefore, NK1R antagonists, such as the clinical drug aprepitant, are currently under investigation as future anticancer agents. In a previous study, NK1R (TACR1) was identified as a potent anticancer target in hepatoblastoma (HB). However, little is known regarding the exact distribution of this target among HB subsets and whether it correlates with clinical features and prognosis. In the present study, mRNA was isolated from 47 children with HB, and reverse transcription-quantitative polymerase chain reaction was performed on the samples to analyze the expression of full-length-TACR1 (fl-TACR1) and truncated-TACR1 (tr-TACR1). These data were correlated with data obtained from 9 tumor-free controls, as well as with the presence of metastasis, PRETEXT, vascular invasion, histology, age of diagnosis, multifocality, CTNNB1 mutation, gender and overall survival. Additionally, the present study investigated a recently described 16-gene signature characterizing HB known to correlate with prognosis. Compared with tumor-free liver tissue, tumorous tissue expressed TACR1 significantly higher for the truncated version (P=0.0301), and by trend also for the full-length version. Accordingly, the expression of fl-TACR1 correlated with the expression of the truncated version (P=0.0074). Furthermore, a low expression of fl-TACR1 correlated with characteristics of the 16-gene signature known to predict prognosis (P=0.0222). However, there was no correlation between tr-TACR1 and the tumor characteristics investigated, including outcome, although a clear trend was observed for some tumor characteristics. The current results reinforced the previously described findings that in HB, tr-TACR1 is overexpressed compared with tumor-free liver tissue. Furthermore, to the best of our knowledge, the present study demonstrated for the first time that tr-TACR1 is expressed ubiquitously among the different subsets of HB. Therefore, NK1R may serve as a potent anticancer target in a large variety of patients with HB, independent of tumor biology and clinical stage.

Low expression of N-myc downstream-regulated gene 2 (NDRG2) correlates with poor prognosis in hepatoblastoma.

BACKGROUND/PURPOSE OF THE STUDY: Despite tremendous progress in therapy, about 30% of patients with hepatoblastoma still succumb to the disease. Thus, the development of improved therapies as well as the identification of prognostic factors are urgently needed. METHODS: In the present study, expression and promoter methylation of the N-myc downstream-regulated gene (NDRG2), a tumor suppressor gene contributing to the regulation of the Wnt signalling pathway, was analysed in 38 hepatoblastoma samples by real-time reverse transcription-PCR and pyrosequencing, respectively. RESULTS: The NDRG2 gene was highly expressed in normal pediatric liver tissue, but was significantly downregulated in heptoblastoma primary tumors. Detailed methylation analysis of CpG sites in the NDRG2 promoter region revealed a general high degree of DNA methylation in hepatoblastoma, which correlated with the suppression of NDRG2. By analyzing clinicopathological features we could demonstrate a strong association between low NDRG2 expression and tumor metastasis. Importantly, the overall survival analysis by Kaplan-Meier revealed that high NDRG2 expression was correlated with a higher survival rate in hepatoblastoma patients. CONCLUSION: Our data show that downregulation of NDRG2 may play an important role in advanced hepatoblastomas.

Development of hypertension is less frequent after bilateral nephron sparing surgery for bilateral Wilms tumor in a long-term survey.

PURPOSE: The option of nephron sparing surgery for unilateral Wilms tumor has been debated in the recent literature. This procedure is being used increasingly to preserve kidney tissue and function. However, nephron sparing surgery is feasible only for selected cases, and a higher local relapse rate has been observed. Moreover, a significant reduction of nephrons is associated with development of renal hypertension and progressive renal failure. We analyzed outcomes after bilateral partial nephrectomy and unilateral partial plus contralateral total nephrectomy in patients with bilateral Wilms tumor. MATERIALS AND METHODS: We analyzed data from the Society of Pediatric Oncology and Hematology database on 22 patients with bilateral Wilms tumor. Kidney size was measured using volumetric analysis of magnetic resonance imaging. Patients were matched with children who had undergone magnetic resonance imaging of the abdomen for other malignancies. RESULTS: Mean kidney volumes after unilateral partial plus total contralateral nephrectomy (66.9 cm(3)) were significantly greater than the reference kidneys (p = 0.028), whereas controls were equal to the bilateral partial nephrectomy group (49.7 cm(3), p = 0.959). Total kidney volume was significantly larger after bilateral partial nephrectomy (102.1 cm(3)) vs unilateral partial plus total contralateral nephrectomy (66.9 cm(3), p = 0.0338). Eight patients (66.7%) had renal hypertension after unilateral partial plus total contralateral nephrectomy but only 2 (20%) after bilateral partial nephrectomy (p = 0.043). Overall survival and relapse rates were equal between the groups and did not correlate with unfavorable histology. CONCLUSIONS: Our findings suggest that patients with bilateral Wilms tumor benefit from bilateral nephron sparing surgery. Hypertension is less common after bilateral partial nephrectomy, and rates of local relapse or disease associated death are distributed equally between the groups.

Impact of postoperative complications on overall survival of patients with hepatoblastoma.

BACKGROUND: Complete resection of hepatoblastoma (HB) is a demanding procedure in advanced tumors. Perioperative complications are still common. The influence of complication rates on course of disease and survival of patients with HB has not been analyzed yet. PROCEDURES: Patients with high risk (HR) HB and standard-risk (SR) HB registered from 1999 to 2008 to the German prospective multicenter study HB99 were evaluated regarding perioperative complications, reasons (e.g., tumor size and vessel involvement) and impact on further treatment and overall survival (OS). RESULTS: Surgical data from 126 patients were available (47 HR-HB, 79 SR-HB). Postoperative complications occurred in 26 (21%) patients consisting of biliary leakage (n = 9), cholestasis (n = 5), deficit of liver perfusion (n = 5) and others (n = 7). Twenty of these 26 patients (77%) required a second operation. The rate of postoperative complications was higher in the HR-group (26%) compared to the SR-group (17%). Patients with vessel involvement had significantly more complications (17% vs. 54%, P = 0.01). Patients with PRETEXT I/II-tumors had the same rate of postoperative complications (19% vs. 20%) as patients with PRETEXT III/IV. Patients of HR-group with postoperative complications showed delayed start in adjuvant chemotherapy (>21 d) (75% vs. 25%, n.s.) combined with significant lower 5-year-OS (75% vs. 50%, P = 0.02). In multivariate analysis postoperative complications were an independent negative prognostic factor for HR-patients (HR 3.1, P = 0.04). CONCLUSIONS: Postoperative complications after HB resection are frequent and associated with worsened OS of patients with HR-HB. One possible reason is delay in postoperative chemotherapy. The approach to precarious liver resection should be carefully planned and executed by specialists.

DARPP-32 binds to tra2-beta1 and influences alternative splicing.

The majority of human genes undergo alternative splicing, which is frequently altered in response to physiological stimuli. DARPP-32 (dopamine and cAMP regulated phosphoprotein, 32kDa) is a component of PKA-dependent signaling pathways. Here we show that DARPP-32 binds directly to the splicing factor tra2-beta1 (transformer 2). DARPP-32 changes the usage of tra2-beta1 dependent alternative exons in a concentration-dependent manner, suggesting that the DARPP-32:tra2-beta1 interaction is a molecular link between signaling pathways and pre-mRNA processing.

Functional complementation of Glra1(spd-ot), a glycine receptor subunit mutant, by independently expressed C-terminal domains.

The oscillator mouse (Glra1(spd-ot)) carries a 9 bp microdeletion plus a 2 bp microinsertion in the glycine receptor alpha1 subunit gene, resulting in the absence of functional alpha1 polypeptides from the CNS and lethality 3 weeks after birth. Depending on differential use of two splice acceptor sites in exon 9 of the Glra1 gene, the mutant allele encodes either a truncated alpha1 subunit (spd(ot)-trc) or a polypeptide with a C-terminal missense sequence (spd(ot)-elg). During recombinant expression, both splice variants fail to form ion channels. In complementation studies, a tail construct, encoding the deleted C-terminal sequence, was coexpressed with both mutants. Coexpression with spd(ot)-trc produced glycine-gated ion channels. Rescue efficiency was increased by inclusion of the wild-type motif RRKRRH. In cultured spinal cord neurons from oscillator homozygotes, viral infection with recombinant C-terminal tail constructs resulted in appearance of endogenous alpha1 antigen. The functional rescue of alpha1 mutants by the C-terminal tail polypeptides argues for a modular subunit architecture of members of the Cys-loop receptor family.

Identification of the microdeletion breakpoint in a GLRA1null allele of Turkish hyperekplexia patients.

Hyperekplexia (startle disease) is a hereditary motor disease caused by mutations within the GLRA1 gene (Chr. 5q33.1), which encodes the alpha1 subunit of the inhibitory glycine receptor (GlyR). While most patients are diagnosed with dominant hyperekplexia associated with point mutations within or adjacent to the channel pore, recessive hyperekplexia is less frequent. Here, we report five new pedigrees of recessive hyperekplexia in apparently unrelated families of Kurdish origin associated with a deletion of exons 1-7 of the GLRA1 gene. The deletion was identical in all families, encompassing 329 Kb of genomic sequence. No other known functional genes were involved, indicating that the GLRA1null allele is distinct from the 5q syndrome. Analysis of the DNA sequence flanking the proximal and distal breakpoint revealed no significant homology of sequences immediately adjacent to the breaks. Consensus sites for Toposiomerase II were detected close to the breakpoint compatible with an illegitimate recombination event. No heterozygous carriers of the deletion allele were detected by screening of 500 individuals from the southeastern Mediterranean region belonging to four different ethnic groups. Hence, the identical nature of the breakpoint junction in all patients and carriers suggests a founder mutation in an ethnic population originating from Turkey.