Determination of tissue tracer transit of Technetium-99m-mercaptoacetyltriglycine diuretic renography in infants with suspected ureteropelvic junction obstruction - A multicenter prospective observational study.

INTRODUCTION: There is an ongoing controversy regarding management of ureteropelvic junction obstruction in infants, with a shift towards a non-operative approach. However, precise predictors of outcome are lacking. Recent studies postulated a high prognostic value of Technetium-99m-mercaptoacetyltriglycine tissue tracer transit with regard to the development of an impaired differential renal function and its potential improvement following pyeloplasty. OBJECTIVE: To evaluate the prognostic value of Technetium-99m-mercaptoacetyltriglycine tissue tracer transit for the occurrence of changes in differential renal function in infants with suspected unilateral ureteropelvic junction obstruction in a prospective observational multicenter study. STUDY DESIGN: Infants below 3 months of age with a unilateral isolated hydronephrosis ≥ grade 3 received ultrasound and Technetium-99m-mercaptoacetyltriglycine diuretic renography at two different time points (timepoint 1 and timepoint 2). Data were analyzed at local centers and at the study center and were collected in an internet-based database system. Tissue tracer transit was determined for each diuretic renography, inter-observer variation for tissue tracer transit and standard parameters for judgement of differential renal function development were assessed. RESULTS: Thirty-seven patients were analyzed. Median age was 11 weeks (7-15) at timepoint 1 and 26 weeks (19-33) at timepoint 2. A delayed tissue tracer transit at timepoint 1 was not associated with deterioration of differential renal function at timepoint 2 in both, locally (10/37 cases) and centrally (4/37) analyzed cases. However, sensitivity and specificity were poor. The intraclass correlation coefficient comparing local and central findings of tissue tracer transit and renal drainage demonstrated poor or fair agreement. Analysis of standard parameters for differential renal function development revealed a prognostic value only for the dichotomized anteroposterior renal pelvic diameter (APD, p = 0.03, 95%-CI 1.2-22.2). DISCUSSION: Regarding the primary endpoint of our study, we could not confirm the hypothesis that delayed tissue tracer transit reliably predicts a subsequent decline in differential renal function in the cohort of patients studied. Whether the low age of the patients, technical problems in the correct assessment of tissue tracer transit by the investigator in early infancy, the study design, or the parameter itself played a role is debated. CONCLUSION: In the presented setting tissue tracer transit was not useful as a predictive parameter for deterioration of differential renal function in infants with suspected unilateral ureteropelvic junction obstruction. Sensitivity and specificity of tissue tracer transit were not sufficient for risk stratification. Improved utility of tissue tracer transit as a marker might be achieved using a different study setting.

Human exome and mouse embryonic expression data implicate ZFHX3, TRPS1, and CHD7 in human esophageal atresia.

INTRODUCTION: Esophageal atresia with or without tracheoesophageal fistula (EA/TEF) occurs approximately 1 in 3.500 live births representing the most common malformation of the upper digestive tract. Only half a century ago, EA/TEF was fatal among affected newborns suggesting that the steady birth prevalence might in parts be due to mutational de novo events in genes involved in foregut development. METHODS: To identify mutational de novo events in EA/TEF patients, we surveyed the exome of 30 case-parent trios. Identified and confirmed de novo variants were prioritized using in silico prediction tools. To investigate the embryonic role of genes harboring prioritized de novo variants we performed targeted analysis of mouse transcriptome data of esophageal tissue obtained at the embryonic day (E) E8.5, E12.5, and postnatal. RESULTS: In total we prioritized 14 novel de novo variants in 14 different genes (APOL2, EEF1D, CHD7, FANCB, GGT6, KIAA0556, NFX1, NPR2, PIGC, SLC5A2, TANC2, TRPS1, UBA3, and ZFHX3) and eight rare de novo variants in eight additional genes (CELSR1, CLP1, GPR133, HPS3, MTA3, PLEC, STAB1, and PPIP5K2). Through personal communication during the project, we identified an additional EA/TEF case-parent trio with a rare de novo variant in ZFHX3. In silico prediction analysis of the identified variants and comparative analysis of mouse transcriptome data of esophageal tissue obtained at E8.5, E12.5, and postnatal prioritized CHD7, TRPS1, and ZFHX3 as EA/TEF candidate genes. Re-sequencing of ZFHX3 in additional 192 EA/TEF patients did not identify further putative EA/TEF-associated variants. CONCLUSION: Our study suggests that rare mutational de novo events in genes involved in foregut development contribute to the development of EA/TEF.

Association Between Exstrophy-epispadias Complex And Congenital Anomalies: A German Multicenter Study.

OBJECTIVE: To further investigate associated anomalies in exstrophy-epispadias complex (EEC) patients congenital uro-rectal malformations network (CURE-Net) database was systematically screened. In literature the EEC comprises a spectrum of anomalies, mainly occurring "isolated" without additional congenital defects. Nevertheless, previous epidemiological studies indicated a higher association with renal, anorectal, and lower neurotubular anomalies, which may originate from the same developmental morphogenetic fields. MATERIALS AND METHODS: Seventy-three prospectively (born since 2009) and 162 cross-sectional recruited EEC patients (born 1948-2008) were analyzed. Associated anomalies were derived from patient's medical data as well as from a physical examination during a physician's interview, classified according to the international statistical classification of diseases and related health problems and grouped with the London Dysmorphology Database. Descriptive statistical analyses were performed. RESULTS: Majority of participants were male (68%) and expressed the classical bladder exstrophy phenotype (71%). Exstrophy variants occurred significantly more often in newborns (21%, P < .0001). Anomalies such as inguinal hernias, skeleton, and joint anomalies were equally present in both groups (P = .65 and P = .67). Heart defects were seen more often in newborns (6%) than in the cross-sectional group (1%; P = .033) and the general German population (1%). In total, 59% of the prospective and 48% of the cross-sectional patients had associated anomalies outside the spectrum (P = .16). CONCLUSION: Phenomenological multicenter data confirmed the dimension of associated anomalies inside and outside the EEC spectrum. The detected anomalies are either important in preparing for the primary reconstruction or later in long-term follow-up. Associated anomalies of EEC should be spotlighted during routine check-up in all EEC patients.

Inosine attenuates spontaneous activity in the rat neurogenic bladder through an A2B pathway.

Neurogenic detrusor overactivity (NDO) is among the most challenging complications of spinal cord injury (SCI). A recent report by us demonstrated an improvement in NDO in SCI rats following chronic systemic treatment with the purine nucleoside inosine. The objective of this study was to investigate the mechanism of action of inosine underlying improvement of NDO. Male Sprague-Dawley rats underwent complete spinal cord transection at T8. Inosine (1 mM) delivered intravesically to SCI rats during conscious cystometry significantly decreased the frequency of spontaneous non-voiding contractions. In isolated tissue assays, inosine (1 mM) significantly decreased the amplitude of spontaneous activity (SA) in SCI bladder muscle strips. This effect was prevented by a pan-adenosine receptor antagonist CGS15943, but not by A1 or A3 receptor antagonists. The A2A antagonist ZM241385 and A2B antagonist PSB603 prevented the effect of inosine. The effect of inosine was mimicked by the adenosine receptor agonist NECA and the A2B receptor agonist BAY60-6583. The inhibition of SA by inosine was not observed in the presence of the BK antagonist, iberiotoxin, but persisted in the presence of KATP and SK antagonists. These findings demonstrate that inosine acts via an A2B receptor-mediated pathway that impinges on specific potassium channel effectors.

The Dilemma of Adolescent Varicoceles: Do They Really Have to Be Repaired?

The primary indication for varicocele repair in adults, that of failed paternity, must be substituted in the adolescent population with surrogate parameters of testicular size differential and semen analysis. Making recommendations based on these two parameters is incredibly difficult because studies often have contradictory findings, different patient populations, and lack of long-term follow up of the key endpoint, paternity. Therefore, it is not a surprise that recommendations for adolescent varicocele repair are general (with some exceptions) and necessarily so because of limitations in quality of evidence. Apart from pain, all indications for varicocele repair in adolescence remain controversial. This highlights the most important task for future studies: to prevent pediatric urologists from allowing a potentially damaging process to go untreated, while at the same time avoiding unnecessary intervention on a highly prevalent condition.

Neonatal Gardner Fibroma Leads to Detection of Familial Adenomatous Polyposis: Two Case Reports.

Gardner fibromas (GFs) have only recently been described as poorly circumscribed tumor-like lesions, which are exceedingly rare in children. GFs are associated with APC gene mutations and therefore with familial adenomatous polyposis (FAP). So far there is only very limited literature on GF in the neonatal period. We present two children with GF diagnosed at birth and subsequent FAP with very different clinical courses. In one case, the disease led to extensive surgery of the thoracic wall and detection of FAP in the father with the need of immediate proctocolectomy. In the other patient (with a positive family history for FAP) the disease remained stable. Our cases indicate that the diagnosis of GF in the neonatal period requires the exclusion of FAP both in the child as well as the parents. Since the clinical behavior of GF cannot be predicted, continuous monitoring is mandatory. Depending on tumor site and growth, individual therapeutic options must be thoroughly considered. Surgical resection, if necessary, has to be inevitably total to prevent recurrence.

More than fetal urine: enteral uptake of amniotic fluid as a major predictor for fetal growth during late gestation.

UNLABELLED: The purpose of our study was to investigate the importance of amniotic fluid (AF) for fetal growth during late gestation using esophageal atresia (EA) patients as a model. In this retrospective cohort study, we compared the z-scores adapted for birth weights (BW z-scores) for each of 517 European newborns with congenital pre-gastric intestinal atresia, i.e., EA, to a European reference population. To account for the influence of the intestinal atresia on fetal growth per se, we compared adapted birth weights for each of 504 European newborns with post colonic intestinal atresia (anorectal malformation (ARM) with atresia of the anus) to the same European reference population. Analysis of the complete cohort showed (i) a significantly higher rate of small for gestational age newborns among EA compared to ARM newborns (p < 0.001) and (ii) significantly lower BW z-scores among EA compared to ARM newborns (p < 0.001). BW z-scores of EA newborns were significantly lower in term compared to preterm newborns with an inverse correlation with gestational age (GA) (Spearman correlation coefficient, r = -0.185, p < 0.001). CONCLUSIONS: Enteral uptake of AF seems to play a pivotal role in fetal growth during late gestation. WHAT IS KNOWN: • Peak velocity of fetal weight gain occurs at 33 weeks of gestation and continues until birth. During this period, fetal growth is mainly characterized by cellular hypertrophy. • Amniotic fluid (AF) comprises large amounts of hormones and growth regulators. What is New: • A significantly higher rate of small for gestational age and lower birth weights and z-scores are observed among newborn infants with congenital pre-gastric intestinal atresia. • These findings suggest that enteral uptake of AF is a major predictor for fetal growth during late gestation.

Heterozygous FGF8 mutations in patients presenting cryptorchidism and multiple VATER/VACTERL features without limb anomalies.

BACKGROUND: The acronym VATER/VACTERL association describes the combination of at least three of the following cardinal features: vertebral defects, anorectal malformations, cardiac defects, tracheoesophageal fistula with or without esophageal atresia, renal malformations, and limb defects. Although fibroblast growth factor-8 (FGF8) mutations have mainly found in patients with Kallmann syndrome, mice with a hypomorphic Fgf8 allele or complete gene invalidation display, aside from gonadotropin-releasing hormone deficiency, parts or even the entire spectrum of human VATER/VACTERL association. METHODS: We performed FGF8 gene analysis in 49 patients with VATER/VACTERL association and 27 patients presenting with a VATER/VACTERL-like phenotype (two cardinal features). RESULTS: We identified two heterozygous FGF8 mutations in patients displaying either VATER/VACTERL association (p.Gly29_Arg34dup) or a VATER/VACTERL-like phenotype (p.Pro26Leu) without limb anomalies. Whereas the duplication mutation has not been reported before, p.Pro26Leu was once observed in a Kallmann syndrome patient. Both our patients had additional bilateral cryptorchidism, a key phenotypic feature in males with FGF8 associated Kallmann syndrome. Each mutation was paternally inherited. Besides delayed puberty in both and additional unilateral cryptorchidism in one of the fathers, they were otherwise healthy. Serum hormone levels downstream the gonadotropin-releasing hormone in both patients and their fathers were within normal range. CONCLUSION: Our results suggest FGF8 mutations to contribute to the formation of the VATER/VACTERL association. Further studies are needed to support this observation.

De novo 13q deletions in two patients with mild anorectal malformations as part of VATER/VACTERL and VATER/VACTERL-like association and analysis of EFNB2 in patients with anorectal malformations.

Anorectal malformations (ARMs) comprise a broad spectrum of conditions ranging from mild anal anomalies to complex cloacal malformations. In 40-50% of cases, ARM occurs within the context of defined genetic syndromes or complex multiple congenital anomalies, such as VATER/VACTERL (vertebral defects [V], ARMs [A], cardiac defects [C], tracheoesophageal fistula with or without esophageal atresia [TE], renal malformations [R], and limb defects [L]) association. Here, we report the identification of deletions at chromosome 13q using single nucleotide polymorphism-based array analysis in two patients with mild ARM as part of VATER/VACTERL and VATER/VACTERL-like associations. Both deletions overlap the previously defined critical region for ARM. Heterozygous Efnb2 murine knockout models presenting with mild ARM suggest EFNB2 as an excellent candidate gene in this region. Our patients showed a mild ARM phenotype, closely resembling that of the mouse. We performed a comprehensive mutation analysis of the EFNB2 gene in 331 patients with isolated ARM, or ARM as part of VATER/VACTERL or VATER/VACTERL-like associations. However, we did not identify any disease-causing mutations. Given the convincing argument for EFNB2 as a candidate gene for ARM, analyses of larger samples and screening of functionally relevant non-coding regions of EFNB2 are warranted. In conclusion, our report underlines the association of chromosome 13q deletions with ARM, suggesting that routine molecular diagnostic workup should include the search for these deletions. Despite the negative results of our mutation screening, we still consider EFNB2 an excellent candidate gene for contributing to the development of ARM in humans.

Inheritance of the VATER/VACTERL association.

VATER/VACTERL association refers to the non-random co-occurrence of the following component features: vertebral defects, anal atresia, cardiac malformations, tracheoesophageal atresia, renal abnormalities, and limb defects. Recently, Solomon et al. (Hum Genet 127:731-733, 2010) observed an increased prevalence of component features among first-degree relatives of VATER/VACTERL patients suggesting that in some patients, the disorder may be inherited. To replicate these findings, we investigated 87 VATER/VACTERL patients with the presence of a minimum of three component features and their first-degree relatives (n = 271). No increase in the overall prevalence of component features was observed in first-degree relatives compared to the general population (χ² = 2.68, p = 0.10). Separate analysis for the prevalence of single component features showed a higher prevalence of tracheoesophageal fistula/atresia among first-degree relatives compared to the general population (OR 17.65, 95% CI 2.47-126.05). However, this was based on occurrence in one family only. Our findings suggest that although familial occurrence renders a genetic contribution likely, the overall risk of recurrence among the first-degree relatives of patients with VATER/VACTERL association is probably very low. Since the patients in the present study were young and no offspring could be studied, estimation of the role of de novo mutations in the development of VATER/VACTERL was not possible.

Measurements of characteristics of time pattern in dose delivery in step-and-shoot IMRT.

BACKGROUND AND PURPOSE: Although intensity-modulated radiotherapy (IMRT) has already shown its clinical benefit, there are some issues which are not yet fully understood. Among these is the question whether the protracted dose delivery due to the lowered dose rate has any radiobiological consequences. To investigate this question, an exact characterization of dose rate profiles in typical clinical plans is needed. Furthermore, such a characterization may lead to an increased knowledge how to improve IMRT technically. MATERIAL AND METHODS: A new IMRT phantom which allows precise measurement of up to nine points of interest simultaneously with pin-point ionization chambers was developed. To examine dose rates, a new software tool (GRAYHOUND) was developed which can measure doses in short time intervals of up to 0.5 s. 250 points in four clinical IMRT plans were examined. A set of parameters was defined to describe the dose rate profiles including the effective fraction time (eft, which is the percentage of the fraction time in which any dose is delivered to a specific point), and a quotient of the percentage of dose delivered in high dose pulses (> 0.01 Gy/s) divided by the percentage of fraction time needed to deliver this dose (d(HD)/t(HD)). RESULTS: These quotients are excellent markers for the inhomogeneity of dose rate delivery in IMRT. In both parameters a wide variance in points of the same plan and between different plans was found. For example, eft ranged between 11.6% and 37.3% in high dose points and the time in which high dose rates are delivered to a single high dose point ranged between 3.6% and 10.1% of total fraction time. CONCLUSIONS: These data show a great inhomogeneity of dose rates not only between different plans but also between different points in the same plan. Biological investigations are needed to quantify the relevance of these inhomogeneities. The parameters which are introduced in this work may be suitable to compare different optimization algorithms in IMRT.

Radiobiological investigation of dose-rate effects in intensity-modulated radiation therapy.

BACKGROUND AND PURPOSE: Intensity-modulated radiation therapy (IMRT) has proven extraordinary capability in physical terms such as target conformity, dose escalation in the target volume, and sparing of neighboring organs at risk. The radiobiological consequences of the protracted dose delivery for cell survival and cell cycle progression are still unclear and shall be examined in this study. MATERIAL AND METHODS: Human lymphoblasts (TK6) and human melanoma cells (MeWo) were irradiated with protocols of increasing dose protraction. In addition, a new biophysical phantom was developed and used to transfer clinical IMRT plans to experimental cell irradiation. Clonogenic cell survival and cell cycle analysis were performed after various irradiation experiments. RESULTS: In a first series of experiments, melanoma cells showed a highly significant increase of survival of 6.0% after protracted dose delivery of 2 Gy compared to conventional fast application with the same dose. Lymphoblastoid cells also showed a significant increase of survival of 2.2%. Experiments with patient plans in the phantom confirmed the trend of increased cell survival after protracted dose delivery. Cells were irradiated at 13 points in four different IMRT plans. In comparison to irradiation with application of the same dose in a classic four-field box, a significantly increased survival of 5.1% (mean value) was determined. CONCLUSION: Even at fraction times of 15-30 min the protracted dose delivery increases the survival rates in cell culture. The altered survival rates indicate the importance of the dose rate in the effectivity of IMRT. Besides physical parameters the consideration of biological factors might contribute to the optimization of IMRT in the future.