The crystal structure of bacteriophage λ RexA provides novel insights into the DNA binding properties of Rex-like phage exclusion proteins

RexA and RexB function as an exclusion system that prevents bacteriophage T4rII mutants from growing on Escherichia coli λ phage lysogens. Recent data established that RexA is a non-specific DNA binding protein that can act independently of RexB to bias the λ bistable switch toward the lytic state, preventing conversion back to lysogeny. The molecular interactions underlying these activities are unknown, owing in part to a dearth of structural information. Here, we present the 2.05-Å crystal structure of the λ RexA dimer, which reveals a two-domain architecture with unexpected structural homology to the recombination-associated protein RdgC. Modelling suggests that our structure adopts a closed conformation and would require significant domain rearrangements to facilitate DNA binding. Mutagenesis coupled with electromobility shift assays, limited proteolysis, and double electron-electron spin resonance spectroscopy support a DNA-dependent conformational change. In vivo phenotypes of RexA mutants suggest that DNA binding is not a strict requirement for phage exclusion but may directly contribute to modulation of the bistable switch. We further demonstrate that RexA homologs from other temperate phages also dimerize and bind DNA in vitro. Collectively, these findings advance our mechanistic understanding of Rex functions and provide new evolutionary insights into different aspects of phage biology.

Polerovirus N-terminal readthrough domain structures reveal molecular strategies for mitigating virus transmission by aphids

Poleroviruses, enamoviruses, and luteoviruses are icosahedral, positive sense RNA viruses that cause economically important diseases in food and fiber crops. They are transmitted by phloem-feeding aphids in a circulative manner that involves the movement across and within insect tissues. The N-terminal portion of the viral readthrough domain (^NRTD) has been implicated as a key determinant of aphid transmission in each of these genera. Here, we report crystal structures of the ^NRTDs from the poleroviruses turnip yellow virus (TuYV) and potato leafroll virus (PLRV) at 1.53-Å and 2.22-Å resolution, respectively. These adopt a two-domain arrangement with a unique interdigitated topology and form highly conserved dimers that are stabilized by a C-terminal peptide that is critical for proper folding. We demonstrate that the PLRV ^NRTD can act as an inhibitor of virus transmission and identify ^NRTD mutant variants that are lethal to aphids. Sequence conservation argues that enamovirus and luteovirus ^NRTDs will follow the same structural blueprint, which affords a biological approach to block the spread of these agricultural pathogens in a generalizable manner.

Crystal structure of the potato leafroll virus coat protein and implications for viral assembly

Luteoviruses, poleroviruses, and enamoviruses are insect-transmitted, agricultural pathogens that infect a wide array of plants, including staple food crops. Previous cryo-electron microscopy studies of virus-like particles show that luteovirid viral capsids are built from a structural coat protein that organizes with T = 3 icosahedral symmetry. Here, we present the crystal structure of a truncated version of the coat protein monomer from potato leafroll virus at 1.80-Å resolution. In the crystal lattice, monomers pack into flat sheets that preserve the two-fold and three-fold axes of icosahedral symmetry and show minimal structural deviations when compared to the full-length subunits of the assembled virus-like particle. These observations have important implications in viral assembly and maturation and suggest that the CP N-terminus and its interactions with RNA play an important role in generating capsid curvature.

AraC-type regulators HilC and RtsA are directly controlled by an intestinal fatty acid to regulate Salmonella invasion

Invasion of the intestinal epithelium is an essential but energetically expensive survival strategy and is, therefore, tightly regulated by using specific cues from the environment. The enteric pathogen Salmonella controls its invasion machinery through the elegant coordination of three AraC-type transcription activators, HilD, HilC, and RtsA. Most environmental signals target HilD to control invasion, whereas HilC and RtsA are known only to augment these effects on HilD. Here we show that a fatty acid found in the murine colon, cis-2-hexadecenoic acid (c2-HDA), represses Salmonella invasion by directly targeting HilC and RtsA, in addition to HilD. c2-HDA directly binds each of these regulators and inhibits their attachment to DNA targets, repressing invasion even in the absence of HilD. Fatty acid binding, however, does not affect HilC and RtsA protein stability, unlike HilD. Importantly, we show that HilC and RtsA are highly effective in restoring HilD production and invasion gene expression after elimination of the repressive fatty acid c2-HDA. Together, these results illuminate a precise mechanism by which HilC and RtsA may modulate invasion as Salmonella navigates through different regions of the intestine, contributing to our understanding of how this enteric pathogen senses and adapts to a diverse intestinal environment while maintaining its virulence.

Bacteriophage λ RexA and RexB Functions Assist the Transition from Lysogeny to Lytic Growth

The CI and Cro repressors of bacteriophage λ create a bistable switch between lysogenic and lytic growth. In λ lysogens, CI repressor expressed from the P_RM promoter blocks expression of the lytic promoters P_L and P_R to allow stable maintenance of the lysogenic state. When lysogens are induced, CI repressor is inactivated and Cro repressor is expressed from the lytic P_R promoter. Cro repressor blocks P_RM transcription and CI repressor synthesis to ensure that the lytic state proceeds. RexA and RexB proteins, like CI, are expressed from the P_RM promoter in λ lysogens; RexB is also expressed from a second promoter, P_LIT , embedded in rexA. Here we show that RexA binds CI repressor and assists the transition from lysogenic to lytic growth, using both intact lysogens and defective prophages with reporter genes under control of the lytic P_L and P_R promoters. Once lytic growth begins, if the bistable switch does return to the immune state, RexA expression lessens the probability that it will remain there, thus stabilizing the lytic state and activation of the lytic P_L  and P_R  promoters. RexB modulates the effect of RexA and may also help establish phage DNA replication as lytic growth ensues.

The N-terminal domain of Staphylothermus marinus McrB shares structural homology with PUA-like RNA binding proteins

McrBC is a conserved modification-dependent restriction system that in Escherichia coli specifically targets foreign DNA containing methylated cytosines. Crystallographic data show that the N-terminal domain of Escherichia coli McrB binds substrates via a base flipping mechanism. This region is poorly conserved among the plethora of McrB homologs, suggesting that other species may use alternative binding strategies and/or recognize different targets. Here we present the crystal structure of the N-terminal domain from Stayphlothermus marinus McrB (Sm3-180) at 1.92 Å, which adopts a PUA-like EVE fold that is closely related to the YTH and ASCH RNA binding domains. Unlike most PUA-like domains, Sm3-180 binds DNA and can associate with different modified substrates. We find the canonical 'aromatic cage' binding pocket that confers specificity for methylated bases in other EVE/YTH domains is degenerate and occluded in Sm3-180, which may contribute to its promiscuity in target recognition. Further structural comparison between different PUA-like domains identifies motifs and conformational variations that correlate with the preference for binding either DNA or RNA. Together these data have important implications for PUA-like domain specificity and suggest a broader biological versatility for the McrBC family than previously described.

The full-length structure of Thermus scotoductus OLD defines the ATP hydrolysis properties and catalytic mechanism of Class 1 OLD family nucleases

OLD family nucleases contain an N-terminal ATPase domain and a C-terminal Toprim domain. Homologs segregate into two classes based on primary sequence length and the presence/absence of a unique UvrD/PcrA/Rep-like helicase gene immediately downstream in the genome. Although we previously defined the catalytic machinery controlling Class 2 nuclease cleavage, degenerate conservation of the C-termini between classes precludes pinpointing the analogous residues in Class 1 enzymes by sequence alignment alone. Our Class 2 structures also provide no information on ATPase domain architecture and ATP hydrolysis. Here we present the full-length structure of the Class 1 OLD nuclease from Thermus scotoductus (Ts) at 2.20 Å resolution, which reveals a dimerization domain inserted into an N-terminal ABC ATPase fold and a C-terminal Toprim domain. Structural homology with genome maintenance proteins identifies conserved residues responsible for Ts OLD ATPase activity. Ts OLD lacks the C-terminal helical domain present in Class 2 OLD homologs yet preserves the spatial organization of the nuclease active site, arguing that OLD proteins use a conserved catalytic mechanism for DNA cleavage. We also demonstrate that mutants perturbing ATP hydrolysis or DNA cleavage in vitro impair P2 OLD-mediated killing of recBC-Escherichia coli hosts, indicating that both the ATPase and nuclease activities are required for OLD function in vivo.

Do repeat ultrasounds affect orchiectomy rate in patients with testicular torsion treated at a pediatric institution?

INTRODUCTION

Testicular torsion is a urological emergency; as the testicular salvage rate decreases with time, prompt intervention is required to restore the blood flow. Interhospital transfers and ultrasound examinations, while clinically essential to proper treatment and diagnosis, may adversely affect outcomes by delaying surgical intervention. Patients transferred to another institution for treatment of testicular torsion may experience a further time delay by undergoing two ultrasound examinations: one at the initial admitting institution and one at the receiving institution. To the knowledge of the authors, no study has yet explored the time delays and outcomes associated with these repeat ultrasounds.

OBJECTIVE

The objective was to investigate the impact of repeat ultrasound imaging on time to treatment and patient outcomes in patients with testicular torsion.

STUDY DESIGN

A retrospective chart review of 133 patients, aged 0-20 years, treated at the authors' institution for testicular torsion was conducted. Neonate patients and patients who did not receive ultrasound were excluded. Demographic and clinical variables were collected from the electronic medical record. Pearson Chi-squared and t-tests were used for univariate comparisons, and multivariate logistic regression analysis was performed to measure the relationships between variables.

RESULTS

Forty-nine percent of patients were primary patients, and 51% were transfer patients. Fifty-two percent of transfer patients received repeat ultrasounds. In comparison to salvaged patients, those who underwent orchiectomy experienced a greater delay between presentation at the institution and surgical intervention (229 min vs 177 min, p = 0.048). The transfer status does not appear to be related to the outcome, i.e. orchiectomy versus salvage. Patients who underwent orchiectomy were more likely than salvaged patients to have received repeat ultrasounds (p = 0.008). Repeat ultrasound patients had three times the likelihood of orchiectomy of single ultrasound patients. In a subset analysis of transfer patients, repeat ultrasound patients were more likely than single ultrasound patients to receive an orchiectomy (p = 0.03).

DISCUSSION

In agreement with previous studies, patients who underwent orchiectomy were found to experience greater treatment delays and trend toward transfer. Specifically, repeat ultrasound and time between presentation and intervention appear to influence patient outcomes. The effect of repeat ultrasound on outcomes appears to be independent of the transfer status. The study was limited by its retrospective nature and small sample size.

CONCLUSION

The analysis suggests that efforts to prevent repeat ultrasounds and minimize the time between presentation and intervention would improve patient outcomes. It is proposed that standardized clinical decision-making procedures, such as the TWIST scoring system, be incorporated into hospital protocols.

Interdisciplinary pain management is beneficial for refractory orchialgia in children

INTRODUCTION

Idiopathic testicular/groin pain can be a difficult entity for children, their families, and caregivers. The role of interdisciplinary pain management has previously been demonstrated in treating chronic orchialgia at the present pediatric pain clinic.

OBJECTIVE

To evaluate the role of interdisciplinary pain management in managing refractory orchialgia. It was hypothesized that children with refractory orchialgia might respond well. Interdisciplinary care was defined as that which crosses two medical disciplines such as a surgical specialty and specialist in analgesia.

SUBJECTS AND METHODS

Pediatric patients were identified who were: ≥ 10 years old; evaluated in the pediatric urology clinic between 2002 and 2012; were diagnosed wtih ICD code 608.9 or had the diagnosis of male genital disorder NOS. Children were included if they presented with orchialgia without an identifiable cause and failed conservative management (rest, scrotal support, Sitz bath, timed voiding, constipation avoidance) including conventional anti-nociceptive analgesics (acetaminophen, non-steroidal anti-inflammatory drugs, opioids). Patient electronic medical records were reviewed retrospectively.

RESULTS

Twenty-two children met inclusion criteria. Mean age was 13.7 years (range 10-17). Nearly half (45%) of the children had chronic medical conditions such as asthma, allergies, and obesity. Twenty-one of the 22 children were referred to the pediatric pain clinic; 15 were evaluated, and one refused treatment. All children evaluated in the pediatric pain clinic were initially offered an empiric anti-neuropathic anti-convulsant (i.e. gabapentin) and/or an anti-depressant (i.e. amitriptyline) before being offered a nerve block. Of the 14 children accepting treatment in the pediatric pain clinic, six were treated solely with an empiric anti-neuropathic anti-convulsant and/or anti-depressant; eight received medications followed by nerve block (seven ilioinguinal-iliohypogastric blocks, one spinal and ilioinguinal-iliohypogastric block) (see Fig. 1). A total of eight of the 14 children (57%) treated by the pain clinic had resolution of pain, with 50% of those treated with medications alone (three out of six children) responding (two responding to gabapentin and a tricyclic antidepressant, one to gabapentin alone); and five out of eight (63%) treated with medications and then nerve block (ilioinguinal-iliohypogastric block) responding. Of the eight children undergoing nerve block, five required more than one block. The time between each block ranged from 4 to 22.6 weeks. Response to nerve block required an average of 1.4 procedures (range 1-2); mean follow-up after nerve block was 2.4 months (range 0.1-4.8).

DISCUSSION

Children with refractory orchialgia often have comorbidities that suggest a multidisciplinary approach would be useful for treating them. The present study found that the majority of children with refractory orchialgia treated in the pediatric pain clinic responded to management. Major limitations, however, included small cohort size and short follow-up, particularly in those children undergoing nerve block. There was also no objective assessment of pain improvement or improvement in quality of life, which could be rectified with a prospective study.

CONCLUSION

Collaboration and early referral for interdisciplinary pain management as one of these multidisciplinary approaches may help to coordinate care and ease patient suffering.

Effect of probiotic Propionibacterium jensenii 702 supplementation on layer chicken performance

The effects of the probiotic, Propionibacterium jensenii 702 (PJ 702), supplementation on egg productivity, egg shell thickness, fatty acid profile of eggs, and body weight in early layer hens were investigated. Twenty eight twenty-week-old starter pullets were evenly divided into a treatment and a control group for an eight week experiment. Each bird in the treatment group received 107 cfu PJ 702 daily in a total volume of 1 ml by oral administration. No adverse effect was observed due to administration of PJ 702, and successful gastrointestinal transit in the bird was demonstrated by recovery of PJ 702 from faeces of the treatment group. Layer production was significantly improved by the supplementation of PJ 702. Total egg weight in the treatment group was significantly higher than the control (P<0.001). Average egg weight for the treatment group was 55.26 g, 4.2% higher than the control which averaged 53.02 g. Moreover, the fatty acid profile was significantly altered by the supplementation of PJ 702. Myristic acid (P<0.001), palmitoleic acid (P=0.001) and all-cis-11,14-eicosadienoic acid (P=0.02) were significantly lower in the treatment group compared to the control group. No difference in egg shell thickness was observed between the treatment and control group (P=0.23). In conclusion, the application of novel probiotic PJ 702 in the early layer hen is safe and effective to promote production and the quality of products in layer husbandry.

Lactobacilli and dairy propionibacterium with potential as biopreservatives against food fungi and yeast contamination

Naturally fermented and raw foods contain a range of organisms that may have benefit as additives in some foods and food processing. In particular, potential anti-fungal properties of these organisms may be potentially utilised as natural alternatives to chemical additives used to delay and prevent spoilage by fungi and yeast. This study examined 12 novel bacteria previously isolated from food as possible biopreservatives. The bacteria from the lactobacilli and dairy propionibacterium groups were tested by agar overlay method for their ability to inhibit the growth of 10 fungi and one yeast commonly associated with food contamination. Eight among eleven tested lactic acid bacteria demonstrated broad spectrum of antifungal activity. Strong fungi inhibition was also demonstrated by the dairy propionibacterium, but efficacy was growth medium dependant. Only one fungi, Geotrichum candidum was highly resistant to the bacteria. Variation between the inhibition results for different bacteria identifies the importance of careful strain selection, and the benefits of strain combinations when selecting biopreservatives for foods.

Prophylactic role of maternal administration of probiotics in the prevention of irritable bowel syndrome

Neonatal stress is a common early life event which alters the development of the endocrine and immune systems. Specifically, exposure to neonatal stress results in alterations to the hypothalamic-pituitary-adrenal (HPA) axis resulting in offspring who hyper-respond to stress in adulthood. Recently, this concept has been applied to the ontogeny of functional gastrointestinal (GI) disturbances such as irritable bowel syndrome (IBS). The high prevalence of this disorder and the ineffectiveness of current treatments results in high direct and indirect costs to the society. Recently, administration of probiotics to neonates has been used as a safe and cost-effective preventative strategy to revoke the long term unfavourable imprinting induced on the gastrointestinal system by early life stressors in animal models of human IBS. It is not as yet known however, whether maternal supplementary probiotics may also contribute to improved GI integrity and gut-associated immune functioning in stressed neonates, if these possible improvements persist into adulthood, or how this protective effect may be mediated. Our hypothesis is an attempt to link this proposed nutritional approach and its possible preventive effects against GI dysfunctions provoked by neonatal stress.

First Stage Approximation of the Exstrophic Bladder in Patients With Cloacal Exstrophy—Should This be the Initial Surgical Approach in all Patients?

PURPOSE

Cloacal exstrophy is rare and it represents a reconstructive challenge. Options for managing the urinary tract include primary closure or approximation of the bladder halves in the midline with later closure. We present our observations and evolving thoughts concerning optimal treatment in these patients.

MATERIALS AND METHODS

We retrospectively reviewed the records of patients with cloacal exstrophy seen in the last 5 years. Initial management was examined, including complete primary closure vs a staged approach. We noted midline defects, spinal cord abnormalities or other anatomical reasons that precluded primary closure.

RESULTS

Seven patients, including 5 females and 2 males, were identified. An omphalocele noted in all 7 patients was closed in 5 at initial operation. All underwent preservation of the hindgut in the fecal stream. Spinal cord tethering was noted in 7 of 7 cases. Complete primary bladder closure was performed in 3 of the 7 patients, while the size of the bladder plates or a large abdominal wall defect precluded closure in the remainder. Continence was not achieved in the 3 cases closed primarily. All patients achieving urinary continence underwent bladder neck closure and augmentation cystoplasty with a continent catheterizable channel.

CONCLUSIONS

Patients with cloacal exstrophy have anatomical issues that can prevent complete primary bladder closure or preclude the achievement of urinary continence. The high incidence of tethered cord places these patients at risk for upper tract changes and bladder decompensation during followup. Despite successful primary closure in 3 of 7 patients all have a tiny bladder and require secondary procedures to become continent. Extensive dissection during the first operation can contribute to more difficult dissection with potential increased morbidity during subsequent surgeries. Therefore, the best initial approach for the typical patient may be closure of the abdominal wall and approximation of the exstrophied bladder halves in the midline. Secondary closure with continent diversion and reconstruction of the external genitalia can be performed at ages 18 to 24 months.

Continent catheterizable channels and the timing of their complications

PURPOSE

We reviewed our experience with continent catheterizable channels with interest in the timing of conduit related complications.

MATERIALS AND METHODS

A retrospective review was performed of the outcome of continent catheterizable channels in all patients between 1998 and 2003 who had undergone construction of an antegrade continence enema and/or a Mitrofanoff procedure using appendix, small bowel or continent cutaneous vesicostomy. We performed a total of 117 such stomas in 37 male and 41 female patients 2.5 to 20 years old (mean age 8.9). For the antegrade continence enema we used appendix in 92% of cases, an ileal Yang-Monti tube in 6% and a cecal tube in 2%. For the continent catheterizable channel we used appendix in 43% of cases, a Yang-Monti tube in 38% and continent cutaneous vesicostomy in 19%.

RESULTS

Continence was achieved in 98% of patients. Followup was 6 to 71 months (mean 28.4). There were 27 channel related complications (23%). Stomal stenosis occurred in 7 antegrade continence enema procedures (14%) within 1 to 10 months (mean 6.2) and in 9 continent bladder channels (13%), including 5 continent cutaneous vesicostomies, within 1 to 24 months (mean 9.4) after surgery. False passages occurred in 5 antegrade continence enema procedures (10%) within 1 to 13 months (mean 3.6) and in 4 continent catheterizable channels (6%) within 1 to 13 months (mean 6.5) after surgery. Of patients with stomal stenosis 50% were treated with surgical revision, while the remainder was successfully treated with dilation. Most false passages were managed by catheter drainage alone. Reasons for revision were contained perforation, colovesical fistula and inability to catheterize. Patient noncompliance appeared to have a role in stomal stenosis.

CONCLUSIONS

Continent catheterizable stomas help patients achieve bowel and bladder continence. Stomal incontinence after reconstruction is rare. In our experience most stoma related complications occurred in the first year after reconstruction. Experience with more patients and longer followup will help determine whether such problems continue to accumulate with time or whether continent stomas function well with time, particularly after the initial period of healing.

MANAGEMENT OF THE FAILED PYELOPLASTY: A CONTEMPORARY REVIEW

PURPOSE

We reviewed our experience with open dismembered pyeloplasty, with specific focus on the presentation and management of failed pyeloplasty in the pediatric population.

MATERIALS AND METHODS

We performed a retrospective review of patients who had undergone open dismembered pyeloplasty between 1998 and 2003. All patients with less than 6 months of followup were excluded from analysis. The patients were followed postoperatively with serial ultrasounds, with renograms reserved for those patients with prolonged, persistent or worsening hydronephrosis, or recurrent symptoms during followup.

RESULTS

A total of 105 pyeloplasties were performed in 103 patients (71 males and 32 females) 1 to 204 months old (mean 60), with an overall success rate of 93.3%. Followup ranged from 6 to 69 months (mean 23). The 7 patients with treatment failure were males 1 to 204 months old (mean 125), who presented most commonly with pain within 3 to 38 months (mean 13.1) after initial surgery. Subsequent ultrasound revealed worsening hydronephrosis, and renography in these patients showed a pattern consistent with obstruction. Five patients underwent initial balloon dilation, in which 1 was successful. In addition, 1 of these patients underwent an unsuccessful antegrade laser endopyelotomy. Six patients (86%) underwent open surgery, consisting of ureterocalicostomy in 3 and reoperative dismembered pyeloplasty in 3. Dense scarring was seen in all patients, 2 patients had a redundant pelvis causing kinking and 2 patients had unrecognized crossing vessels. Overall salvage rate was 100% with continued followup of 3 to 50 months (mean 18).

CONCLUSIONS

Dismembered pyeloplasty was successful in the vast majority of patients. In our series failures occurred as late as 3 years postoperatively, although most presented within 12 months of followup. Excluding routine postoperative nuclear renography did not seem to affect our ability to identify these cases. Although anatomical features such as renal pelvic size may have a role, failure is most likely secondary to technical issues, including missed crossing vessels and dependency of the anastomosis. In this series failed pyeloplasties did not respond well to balloon dilation, likely due to scar formation. Our current practice is to manage failures by open surgery, although endoscopic management by an incision may be an option.

Signal analysis of total internal reflection fluorescent speckle microscopy (TIR-FSM) and wide-field epi-fluorescence FSM of the actin cytoskeleton and focal adhesions in living cells

Fluorescent speckle microscopy (FSM) uses low levels of fluorescent proteins to create fluorescent speckles on cytoskeletal polymers in high-resolution fluorescence images of living cells. The dynamics of speckles over time encode subunit turnover and motion of the cytoskeletal polymers. We sought to improve on current FSM technology by first expanding it to study the dynamics of a non-polymeric macromolecular assembly, using focal adhesions as a test case, and second, to exploit for FSM the high contrast afforded by total internal reflection fluorescence microscopy (TIR-FM). Here, we first demonstrate that low levels of expression of a green fluorescent protein (GFP) conjugate of the focal adhesion protein, vinculin, results in clusters of fluorescent vinculin speckles on the ventral cell surface, which by immunofluorescence labelling of total vinculin correspond to sparse labelling of dense focal adhesion structures. This demonstrates that the FSM principle can be applied to study focal adhesions. We then use both GFP-vinculin expression and microinjected fluorescently labelled purified actin to compare quantitatively the speckle signal in FSM images of focal adhesions and the actin cytoskeleton in living cells by TIR-FM and wide-field epifluorescence microscopy. We use quantitative FSM image analysis software to define two new parameters for analysing FSM signal features that we can extract automatically: speckle modulation and speckle detectability. Our analysis shows that TIR-FSM affords major improvements in these parameters compared with wide-field epifluorescence FSM. Finally, we find that use of a crippled eukaryotic expression promoter for driving low-level GFP-fusion protein expression is a useful tool for FSM imaging. When used in time-lapse mode, TIR-FSM of actin and GFP-conjugated focal adhesion proteins will allow quantification of molecular dynamics within interesting macromolecular assemblies at the ventral surface of living cells.

An in vitro model for investigating intestinal adhesion of potential dairy propionibacteria probiotic strains using cell line C2BBe1

AIMS

The purposes of this study were to screen the adhesion properties of dairy propionibacteria strains and evaluate whether C2BBe1 could be used in the screening of potential probiotic strains.

METHODS AND RESULTS

Thirteen dairy propionibacteria strains and two control strains, Lactobacillus acidophilus MJLA1 and Bifidobacterium lactis BDBB2, were tested for adhesion to C2BBe1. Electron microscopic observations demonstrated that the control strains, L. acidophilus MJLA1 and B. lactis BDBB2, had similar adhesive ability to C2BBe1 as had been previously shown to Caco-2. Only one of the 13 strains of dairy propionibacteria, strain P. jensenii 702, demonstrated adhesion to C2BBe1.

CONCLUSIONS

C2BBe1 can provide an alternative to Caco-2 for assessing in vitro adhesion properties of probiotic strains. Adhesion properties of dairy propionibacteria were strain-dependent.

SIGNIFICANCE AND IMPACT OF THE STUDY

C2BBe1 is highly suitable for application in bacterial adhesion studies, and was used successfully to select a new potential probiotic.

Is postoperative cystography necessary after ureteral reimplantation?

OBJECTIVES

To evaluate the patients in our practice to determine whether postoperative cystography was useful in monitoring the outcome after ureteroneocystostomy. Surgical repair of vesicoureteral reflux is the treatment of choice after medical therapy failure. Radiographic evaluation by ultrasonography or voiding cystourethrography (VCUG) is commonly used postoperatively to evaluate for urinary tract obstruction or persistent reflux. However, imaging modalities are not without cost, both in monetary terms and in terms of radiation exposure and trauma to the child.

METHODS

We reviewed the records of all patients who underwent ureteroneocystostomy without ureteral tapering at our institution between January 1, 1996 and December 31, 1999 for primary vesicoureteral reflux. These records were evaluated with respect to the type of surgical procedure, preoperative and postoperative clinical course, and radiographic studies performed.

RESULTS

We performed reimplantation on 267 renal units in 153 patients. The surgical technique was the Cohen cross-trigonal in 120 renal units (45%), Glenn-Anderson ureteral advancement in 92 (35%), and modified Leadbetter-Politano ureteral advancement in 55 (20%). All patients underwent imaging with ultrasonography within 6 weeks of surgery. The follow-up ranged from 4 to 42 months (average 14.2). Between 3 and 8 months postoperatively, 61 patients underwent imaging with VCUG. We identified persistent reflux in six renal units. Four of six had marked improvement in their reflux. All the patients with persistent reflux were asymptomatic, including 2 patients who were no longer receiving antibiotics. Four patients developed febrile urinary tract infections postoperatively. Three of the four underwent imaging with VCUG after treatment; all three had no evidence of reflux.

CONCLUSIONS

In our population, the addition of VCUG to the postoperative evaluation did not allow us to identify those patients at risk of febrile urinary tract infections. Patients in whom persistent reflux was identified were all asymptomatic. We continue to monitor patients with ultrasonography, but believe that VCUG often provides little benefit to these children.

Early evolution of bladder emptying after myelomeningocele closure

OBJECTIVES

To analyze bladder emptying in newborns with spina bifida after closure of the myelomeningocele defect. Manipulation of the spinal cord and nerve roots results in temporary changes in bladder function in many settings.

METHODS

We reviewed 62 consecutive newborn patients who underwent closure of a myelomeningocele defect at our institution from January 1990 to December 1997. We examined the catheterized urine volumes obtained before and after closure, radiographic and urodynamic studies, and the subsequent need for intermittent catheterization. Poor bladder emptying was defined as most catheterized urine volumes greater than 10 mL (20% of expected bladder capacity). Adequate follow-up was available for 54 patients for a period of 4 to 96 months (mean 42). One patient with posterior urethral valves was excluded from the study, leaving 53 for evaluation.

RESULTS

Of the 53 patients, 4 with high outflow resistance and dyssynergy never emptied the bladder adequately before or after closure. Of the remaining 49 patients, 6 (12%) emptied well immediately after the myelomeningocele repair. In the other 43 (88%), the bladder did not empty as well after closure. The mean volume obtained with catheterization after closure was 20 mL, significantly higher (P <0.001) than the mean volume obtained before repair (6.5 mL) or after resumption of better spontaneous emptying (4 mL). Intermittent catheterization done for poor emptying was required for an average duration of 11 days (range 2 to 42). Of the 43 patients with poor emptying immediately after closure, 32 (74%) required catheterization for 2 weeks or less; the remaining 11 (26%) required catheterization for 2 to 6 weeks. Despite the relatively early resumption of good emptying, numerous patients (19 of 49) required additional intervention (clean intermittent catheterization or vesicostomy) before attempts to toilet train.

CONCLUSIONS

A clinical pattern similar to spinal shock does occur in most newborns after closure of a myelomeningocele defect. Resumption of near-complete emptying usually occurs less than 2 weeks after repair but may require up to 6 weeks.

Angiotensin type II receptor expression and ureteral budding

PURPOSE

Deletion of the angiotensin type II receptor gene (Agtr2) in mice results in a spectrum of urinary tract anomalies similar to that in humans. The mechanism behind this anomalous development is poorly understood. We evaluated Agtr2 expression as it relates to normal and abnormal ureteral budding.

MATERIALS AND METHODS

A total of 400 wild type mice were inspected at birth for gross evidence of a urinary tract anomaly. In addition, the urinary tracts of 30 wild type embryos were evaluated at 11.0/11.5 and 13.5 weeks of gestation. These embryos were examined for ureteral budding site via section and whole mount in situ hybridization with c-ret probe and Agtr2 expression via in situ hybridization with Agtr2 riboprobe. There were 740 newborn mice homozygous for the null mutation of Agtr2 also evaluated along with 55 angiotensin type II knockout embryos at the aforementioned gestational ages.

RESULTS

All wild type newborn animals were grossly normal. Of the angiotensin type II knockout newborns 23 (3.1%) had gross abnormalities of the urinary tract at birth. The predominant finding was a duplicated collecting system associated with a hydronephrotic upper pole moiety. These duplicated collecting systems fulfilled the Meyer-Weigert law. Interestingly, 25 (59.5%) of the knockout embryos showed abnormal ureteral budding. However, in wild type embryos Agtr2 was expressed at this "ectopic" cranial site between the wolffian duct and metanephric mesenchyme.

CONCLUSIONS

Although not the sole regulator, angiotensin type II receptor expression may have a role in the embryological development of the urinary tract by inhibiting aberrant ureteral budding. A defect in this inhibitory process appears to cause ectopic ureteral budding, and may subsequently lead to renal dysplasia and other congenital anomalies of the kidney and urinary tract.

Small intestinal submucosa as a urethral coverage layer

PURPOSE

Urethrocutaneous fistula is the most common complication of hypospadias surgery. Numerous techniques have been used to decrease the incidence of this complication and the use of biocompatible materials in surgery has expanded the options in difficult situations. We hypothesized that porcine small intestinal submucosa may be used as a coverage layer after urethral surgery. We evaluated the histological changes associated with small intestinal submucosa when used as a coverage layer over the urethra in a rabbit model.

METHODS AND METHODS

We performed urethral surgery in 16 New Zealand White rabbits divided into 4 animals each in groups 1-sham operation with penile degloving only, 2-penile degloving and small intestinal submucosa patch placement, 3-urethrotomy without a patch and 4-urethrotomy with a small intestinal submucosa patch. The graft edges were marked with permanent suture at surgery for later identification. All rabbits were maintained for 6 weeks before sacrifice. The urethra of each animal was then serially sectioned and examined histologically.

RESULTS

Histological examination of animals with an small intestinal submucosa patch revealed a foreign body tissue reaction with an infiltrate of histiocytes, giant cells and lymphocytes in the area of graft placement. There was no histological evidence of remaining small intestinal submucosa patch in any sections. The urethral mucosa healed normally in all cases in which it was disrupted. There was no evidence of acute or chronic inflammation in any group 1 or 2 nonsmall intestinal submucosa animals and none in the animals with a small intestinal submucosa graft in areas other than the former graft site. There were also no urethrocutaneous fistulas in any of the 8 rabbits that underwent urethrotomy.

CONCLUSIONS

Small intestine submucosa provides an adequate coverage layer in the rabbit penis after urethrotomy. Histologically the foreign material did not alter normal healing of the urethral mucosa, although it did appear to cause an infiltration of histiocytes, giant cells and lymphocytes. Small intestinal submucosa has previously been studied as a scaffold on which tissue may be remodeled or may regenerate. Our study shows that small intestinal submucosa did not interfere with normal tissue healing in this animal model. When used as a urethral coverage layer, it appears to provide extra tissue between the urethra and skin. Small intestinal submucosa may potentially decrease the incidence of urethrocutaneous fistula after urethral surgery.

Determination of the efficacy of preservation of non-eye area water-miscible cosmetic and toiletry formulations: collaborative study

A collaborative study was conducted to test a method developed to distinguish between adequately and inadequately preserved cosmetic formulations. Nineteen laboratories participated in the study. Samples tested included shampoos, hair conditioners, oil-in-water emulsions, and water-in-oil-emulsions. Triplicate samples of 4 adequately preserved and 4 inadequately preserved cosmetic products were tested by each collaborative laboratory. Results showed that all inadequately preserved shampoo and conditioner samples failed to meet the acceptance criteria for adequately preserved formulations. Of the 51 preserved samples, 49 shampoos and 48 conditioners met the criteria for adequate preservation. All samples of inadequately preserved water-in-oil emulsions and oil-in-water emulsions failed to meet the acceptance criteria, whereas all adequately preserved emulsion formulations met the acceptance criteria.

Congenital anomalies of the kidney and urinary tract--role of the loss of function mutation in the pluripotent angiotensin type 2 receptor gene

PURPOSE

Recent studies of the human genome and genetic engineering experiments in mice revealed that congenital anomalies of the kidney and urinary tract commonly seen in newborns in various anatomical forms are polygenic disease, that is a disease caused by simultaneous defects in multiple genes. We discuss some possible genetic explanations of the classic theories of the formation of congenital kidney and urinary tract anomalies.

MATERIALS AND METHODS

We reviewed classic and current theories regarding urinary tract development. Included in our review are recent results from our laboratory evaluating the genetic role of normal and abnormal urinary tract development.

RESULTS

We observed a genetic abnormality that may explain many classic anatomical theories of congenital kidney and urinary tract anomalies. One of the genes involved in urinary tract ontogenesis is the angiotensin type 2 receptor gene, which is the "other" angiotensin receptor. While the type 1 receptor mediates essentially all known actions of angiotensin, including its hypertensive effect, relatively little is known about the angiotensin type 2 receptor. Careful dissection studies in mutant mouse embryos selectively lacking the angiotensin type 2 receptor gene revealed that this gene is pleiotropic, that is its defect causes not only ectopic ureteral budding from the wolffian duct, but also disturbance in other subsequent ontogenic events that are critical for the normal growth of the kidney and urinary tract.

CONCLUSIONS

Many congenital anomalies of the kidney and urinary tract appear to share a common genetic cause. While these anomalies are caused by various genetic hits, abnormalities in the angiotensin type 2 receptor gene are often involved in this anomalous development. This review article offers a better understanding of the genetics involved in urinary tract development and ties some of the newly emerging genetic theories with classic anatomical theories.

The use of radiography, urodynamic studies and cystoscopy in the evaluation of voiding dysfunction

PURPOSE

Children with dysfunctional voiding disorder often undergo radiological, cystoscopic or urodynamic evaluation to identify an anatomical or organic cause. We determined the role of these studies in the evaluation, management and ultimate outcome of a large patient population with voiding dysfunction at a single institution.

MATERIALS AND METHODS

We retrospectively evaluated the records of 1, 153 children with dysfunctional voiding disorder treated from 1990 to 1999. A thorough history and physical examination with specific emphasis on voiding patterns were done and urinalysis was performed in all cases. Ultrasound of the urinary system and excretory urography were done in 1,050 (91%) and 24 (2%) patients, respectively, while voiding cystourethrography was performed in 672 (58%), including 564 with a history of nonfebrile urinary tract infection. Cystoscopy and a formal urodynamic study were performed in 61 (5%) and 40 (3.5%) cases, respectively.

RESULTS

Mean patient age at referral was 6 years (range 3 to 14). Of the children 74% were girls and 26% were boys. Physical examination of the abdomen, back, genitalia and neurological system was unremarkable in all cases. Ultrasound of the upper urinary system was normal in 1,018 patients (97%) and showed insignificant pyelectasis in 32 (3%). All 24 excretory urography studies were normal and voiding cystourethrography was normal in 470 of 672 cases (70%). Unilateral and bilateral low grade, and unilateral high grade reflux was present in 108, 19 and 3 patients, respectively. Urodynamic studies were performed in 40 children who did not respond to standard treatment. We noted detrusor instability in 16 patients, detrusor-sphincter dyssynergia in 6 and sensory abnormality in 3, while the study was completely normal in 10. Cystoscopy revealed normal findings in 17 cases, trabeculations in 21, inflammation in 20 and type 1 posterior urethral valves in 2.

CONCLUSIONS

The incidence of upper tract changes and positive anatomical findings in children with voiding dysfunction is too low to justify routine radiological evaluation and cystoscopy. However, in those who present with a nonfebrile urinary tract infection there remains an important role for voiding cystourethrography. We do not recommend routine urodynamics in children with voiding disorder because this study does not change therapy or influence the final outcome. Thorough history and physical examination lead to the correct diagnosis and treatment in the majority of children. A focus on correcting faulty voiding behavior with the judicious administration of antibiotics and anticholinergic therapy leads to a favorable outcome in most cases.

The urodynamic profile of myelodysplasia in childhood with spinal closure during gestation

PURPOSE

Spinal dysraphism is the most common cause of neurogenic bladder dysfunction in newborns. Urodynamic findings in these patients include uninhibited bladder contractions, bladder areflexia, decreased compliance and detrusor-sphincter dyssynergia. Early urodynamic studies are recommended for spina bifida to help identify bladder characteristics that may cause a risk of upper tract deterioration. We recently evaluated a new early type of intervention involving closure of the neural tube defect during gestation in 25 patients at our institution. We hypothesize that this procedure results in decreased exposure of the spinal cord to amniotic fluid, which may improve neurological function. To date we have evaluated 16 of the 25 patients with video urodynamics. We compared the results to those in the literature on patients with myelomeningocele and without prenatal intervention.

MATERIALS AND METHODS

We performed urodynamic testing in 16 patients with a mean age of 6.5 months, including cystometrography, fluoroscopic evaluation of filling and voiding, pelvic floor electromyography and post-void residual urine measurement. In addition, we retrospectively reviewed renal ultrasound, voiding cystourethrography, catheterization need, number of urinary tract infections and medication in these cases.

RESULTS

Uninhibited detrusor contractions and an areflexic bladder were identified in 6% and 43% of patients, respectively, while 19% had decreased compliance and 75% had leak point pressure greater than 40 cm. water. Mean bladder capacity was 40 cc and 31% of patients had much lower capacity than expected for age. Previous renal ultrasound and voiding cystourethrography showed evidence of upper tract dilatation and reflux in 2 cases, respectively. Intermittent catheterization and anticholinergic therapy were required by 1 patient each and 1 had a significant urinary tract infection.

CONCLUSIONS

Urodynamic findings in this population are comparable to those previously reported in the literature in patients with spina bifida without prenatal closure of the spinal defect. The lower incidence of urinary tract infection and reflux in our study probably represents more aggressive early urological management rather than neurological improvement. These urodynamic studies were performed early in life and future evaluation may ultimately reveal improved bladder function compared with that in others with myelodysplasia. However, at this time we recommend that patients who undergo spinal cord defect closure during gestation be evaluated and treated in the same manner as those with myelomeningocele but without fetal intervention.

How well do patients with exstrophy actually void?

PURPOSE

Achieving continence and preserving renal function are goals in the care of patients with bladder exstrophy. The Young-Dees-Leadbetter bladder neck reconstruction should ideally provide continence and normal voiding dynamics without the need for intermittent catheterization. We review our experience with bladder neck reconstruction in this population with emphasis on voiding dynamics among those patients doing well.

MATERIALS AND METHODS

We retrospectively analyzed all patients with the exstrophy-epispadias complex seen at our institutions since 1985. We reviewed staged reconstruction in 53 patients, including 31 with classic bladder exstrophy, 4 with exstrophy variants and 18 with incontinent epispadias. Patients with additional neurogenic dysfunction were excluded from study. Subjective and objective data regarding voiding function and complications were collected.

RESULTS

Complete reconstruction for continence was performed in 38 cases, of which 11 that required bladder augmentation with bladder neck reconstruction or who had a different primary continence procedure were excluded from study. The remaining 27 patients treated with the Young-Dees-Leadbetter bladder neck reconstruction had 2 or more years of followup (mean 5.9). Dry intervals of at least 2 hours were achieved by 18 patients and all were considered by parents to void well. Despite near or total subjective continence and "good" voiding, 13 of these 18 patients (72%) have clinical problems related to emptying, which include recurrent urinary tract infections in 10, epididymitis in 2 and bladder calculi in 4. Objective urodynamic parameters confirm poor voiding in most patients.

CONCLUSIONS

Bladder neck reconstruction in patients with exstrophy can achieve continence without intermittent catheterization. In our experience patients who achieve these goals have an alarming frequency of clinical and urodynamic problems related to emptying. One must question the normalcy of the voiding pattern and price to achieve continence among patients with exstrophy.

The role of hypercalciuria in a subgroup of dysfunctional voiding syndromes of childhood

PURPOSE

Idiopathic hypercalciuria is believed to be the cause of a variety of urinary tract complaints in clinical pediatrics, including urinary frequency, urgency, and/or dysuria, often associated with gross or microscopic hematuria. In children noncalculous manifestations of idiopathic hypercalciuria are reportedly more common than urolithiasis. We determine the use of the calcium-to-creatinine ratio for the evaluation of different subsets of functional voiding disorders.

MATERIALS AND METHODS

We retrospectively evaluated 288 patients with functional voiding disorders during the last 8 years. Patients presenting with isolated urinary tract infection were not included in the study. A thorough history with emphasis on voiding patterns was elicited and a routine urinalysis was performed in all patients. Patients were divided into 5 groups of 22 with total gross hematuria and dysfunctional voiding pattern, 102 with microhematuria and dysfunctional voiding pattern, 66 with isolated childhood daytime frequency, 45 with the isolated dysuria syndrome and 53 with combined childhood frequency-urgency-dysuria syndrome. The season at presentation was noted to determine a seasonal pattern. In 149 patients urine was evaluated for a spot calcium-to-creatinine ratio.

RESULTS

Mean age of the 95 (33%) males and 193 (67%) females was 6.1 years (range 2 to 14) and mean duration of symptoms was 10 months (1 week to 10 years). The incidence of idiopathic hypercalciuria was 28% in cases with gross hematuria and dysfunctional voiding, 30% with microscopic hematuria and dysfunctional voiding, 21% with pure childhood daytime frequency, 22% with pure dysuria, and 28% with frequency, urgency and dysuria. The patients were treated predominantly with behavioral therapy, correction of faulty voiding habits, anticholinergics and minor diet modification in some. Mean followup of 6.5 months (range 1 month to 10 years) was available for 153 patients (53%). Resolution of symptoms along with marked improvement in voiding habits was noted in 136 (89%) patients, moderate improvement in 10 (6.5%) and persistent symptoms with minimal improvement in 7 (4.5%). Treatment with thiazides was used in only 6 (2%) patients who had intractable symptoms and a markedly elevated urine calcium-to-creatinine ratio of whom 5 responded favorably.

CONCLUSIONS

Idiopathic hypercalciuria may have a significant role in cases of functional voiding disorders. It affects the different subsets of voiding disorders with remarkable consistency but the exact mechanism remains unknown. Although a significant number of patients with voiding dysfunction have an elevated calcium-to-creatinine ratio, the majority respond to standard behavioral therapy and pharmacotherapy in the form of anticholinergics, and treatment directed toward hypercalciuria is not required in most cases.

Y-to-I wrap: use of the distal spongiosum for hypospadias repair

PURPOSE

Rather than resecting the distal spongiosum lateral to the open urethra for hypospadias, we mobilized this tissue with the urethral plate away from the corpora cavernosa, subsequently wrapping it around various types of urethroplasty to prevent fistula formation.

MATERIALS AND METHODS

The distal spongiosum was preserved and used for coverage in 25 hypospadias repairs in 1 year. We initially applied it in this manner when the distal spongiosum persisted as a pillar of healthy erectile tissue but later when the distal tissue appeared more fibrous in nature. The wrap was used to cover various types of urethroplasty, including advancement in 6 cases, tubularization in 10, flip-flap repair in 6 and an island onlay pedicle graft in 3.

RESULTS

All patients have at least 1 year of followup. There has been no fistula formation or residual chordee. In 1 patient minor meatal retraction did not require a secondary procedure. Cosmetic results have been good.

CONCLUSIONS

A distal wrap of corpus spongiosum may be used to avoid fistula formation without causing residual or recurrent curvature. It re-creates a nearly normal urethra in some cases.

Coronal cuff: a problem site for buccal mucosal grafts

PURPOSE

Urethral reconstruction of complex hypospadias or epispadias continues to present a significant challenge. Buccal mucosa as an onlay or tube graft is an excellent option when faced with paucity of penile skin. We identified the factors that lead to success or failure in these repairs.

MATERIALS AND METHODS

During 6 years we placed 34 buccal mucosal grafts in 31 patients to repair complex hypospadias and epispadias. Penile skin was preferentially used for urethroplasty but a free buccal mucosal graft was used for reconstruction due to lack of adequate penile skin. The cases were complicated with an average of 5 previous unsuccessful repairs each in 16. Grafts ranged from 1.5 to 10 cm. and 10 patients required pieced grafts. We created 1 combination, 16 onlay and 17 full tube grafts. Buccal mucosa was used with a Thiersch-Duplay urethroplasty in 8 patients.

RESULTS

Anastomotic stricture in 5 patients was proximal in 4. Fistula was a complication in 13 grafts that generally developed on the distal shaft, particularly at the coronal cuff. Of the 7 patients who underwent proximal Thiersch-Duplay urethroplasty with a distal buccal graft 6 had a coronal fistula. Fistula was more common with tube and pieced than with onlay grafts.

CONCLUSIONS

Fistula is overwhelmingly the most common complication after buccal mucosal graft urethroplasty. Most fistulas develop at the coronal cuff, and we suspect that skin coverage and potential blood supply have not been good in that region. Anticipation of this problem during stage 1 of hypospadias repair would allow more advantageous distribution of the existing penile skin. Good distal skin coverage cannot be compromised in these complex cases.

Repair of hypospadias complications using the previously utilized urethral plate

OBJECTIVES

To review our results of patients who underwent repeat hypospadias surgery using local skin flaps with preservation of the urethral plate.

METHODS

We retrospectively reviewed the medical records of all patients who underwent a reoperative hypospadias repair using the urethral plate between 1988 and 1996. A total of 53 patients were identified who developed either a large fistula (47 patients) or severe stricture (6 patients) after the initial repair. Seventeen patients underwent a repeat Mathieu flip-flap and 36 an onlay flap. The mean age at the time of surgery was 5.2 years (range 1 to 27). The mean duration of follow-up was 17 months (range 6 to 108).

RESULTS

The initial failed hypospadias repair was corrected with a single procedure in 44 (83%) of the 53 patients. The 9 patients who had further complications required 17 additional procedures. A meatal-based flap had been used in 4 of these patients and an onlay flap in 5. Three of the 9 patients who had further complications presented with urethral strictures after the previous repair.

CONCLUSIONS

Fistula and stricture are common complications of hypospadias surgery. The use of the urethral plate in primary repairs has helped decrease the complication rate. We report the effectiveness of using local skin flaps and preserving the urethral plate in complex reoperative hypospadias surgery. These techniques were successful in 83% of these challenging patients. Patients with stricture after hypospadias surgery are at increased risk of further complications.

Does every patient with prenatal hydronephrosis need voiding cystourethrography?

PURPOSE

Prenatal ultrasound has allowed early identification of urinary tract abnormalities that may require urological followup or early intervention. While all children with prenatal hydronephrosis should undergo ultrasound within the first few weeks of life, we believe that there is a subset of postnatal hydronephrosis for which voiding cystourethrography can be avoided if careful observation is continued.

MATERIALS AND METHODS

For 5 years 175 infants with a history of prenatal hydronephrosis were evaluated by ultrasound. Of 60 infants with less than Society for Fetal Urology grade II unilateral or bilateral hydronephrosis 44 underwent voiding cystourethrography as part of the early evaluation and 16 were observed without voiding cystourethrography. Four infants for whom we would routinely obtain voiding cystourethrography were excluded from study due to severe prenatal hydronephrosis, renal duplication, hydroureter, ipsilateral small or echogenic kidney and grade II or higher hydronephrosis.

RESULTS

Voiding cystourethrography was positive in 6 of the 40 infants (15%) with less than grade II hydronephrosis. Of these cases 3 had grade III or higher vesicoureteral reflux and 1 with high grade reflux required reimplantation. None of the 16 patients followed without voiding cystourethrography has required further evaluation or intervention. In all patients with negative or no voiding cystourethrography parenchyma was preserved and hydronephrosis stabilized or resolved.

CONCLUSIONS

Prenatal and postnatal ultrasound in infants should be used to guide further urological evaluation. Among infants with less than grade II hydronephrosis postnatally 15% had reflux on voiding cystourethrography, which is significantly higher than that reported among normal children (approximately 1%). However, none of the 16 infants observed without voiding cystourethrography on short-term antibiotic prophylaxis had deleterious renal events with 6 months to 4.5 years of followup. Therefore, we question the actual significance of the reflux detected in the first cohort of infants. Voiding cystourethrography can provide a definitive answer. However, we also believe that it is not absolutely mandatory based on the outcome in the observed group. With careful counseling and followup most patients with less than grade II hydronephrosis can be observed without urological sequela.

How they begin and how they end: classic and new theories for the development and deterioration of congenital anomalies of the kidney and urinary tract, CAKUT

CAKUT are problems that often require surgical intervention or, in the worst case, lead to renal failure and the need for dialysis and/or renal transplantation. It is believed that these anomalies share a common genetic cause and to date there has been no good animal model with which to study these abnormalities. Although the abnormal interaction between the ureteral bud and metanephric blastema leads to renal hypodysplasia, vesicoureteral reflux, and ectopic ureters to name a few, the genetic and biochemical modulation of urinary tract development is not understood. Studies using the mouse strain mutant for angiotensin type 2 (AT2) receptors have given new insight into this mystery. The animals show defective apoptosis of undifferentiated mesenchymal cells in the area surrounding the developing kidney and urinary tract. This abnormal apoptosis may well interfere with the normal interaction between the ureteral bud and metanephric blastema resulting in CAKUT. This abnormal interaction would theoretically lead to preexisting intrinsic abnormalities of the kidney, which are programmed and take effect early in embryonic development. In the worst cases, the renal abnormalities would lead to progressive deterioration of renal function. Undoubtedly, there are more genes and biochemical modulators involved in this process other than the RAS and AT2 receptors. Our current animal model gives new and unique possibilities with which to study development of the kidney and urinary tract and ultimately seek ways of preventing an often debilitating disease process.

Concealed penis in childhood: a spectrum of etiology and treatment

PURPOSE

Concealed penis is an uncommon condition due to poor skin fixation at the base of the penis, cicatricial scarring after penile surgery and excessive obesity. The condition varies in severity and several surgical options are available, such as excision of previous scarring, degloving the penile shaft, reconstructing the penile shaft skin with flaps, fixing the penile skin at the penopubic and penoscrotal angles, and removing excess suprapubic fat.

MATERIALS AND METHODS

We reviewed the records of 43 patients treated for concealed penis from 1993 to 1998. We categorized the cases as type 1-congenital concealed penis, type 2-concealed penis due to scarring from previous surgery and type 3-complex cases involving excessive obesity. Cases were reviewed in regard to surgical techniques and outcomes. We identified 18 type 1, 18 type 2 and 7 type 3 cases. Mean age of type 1 patients at surgery was 12.4 months with 1 patient presented at age 7 years. None had previously undergone penile surgery. All patients underwent complete penile degloving. To reconstruct the penile shaft flaps or Z-plasties with penile skin were used in 12 patients and scrotal skin flaps were used in 2. In 12 patients the penile skin was fixed at the penoscrotal and penopubic angles to maintain penile length and in 2 excess fat was excised. Mean age of type 2 patients at surgery was 19.8 months. All had previously undergone surgery, including hypospadias in 1 and circumcision in 17. All patients underwent complete penile degloving and the cicatricial scar that trapped the penis was excised. Penile skin flaps and Z-plasties were used in 12 cases, scrotal skin flaps were used for reconstruction in 2 and skin grafting was done in 1. In 10 patients the penile skin was fixed with sutures to maintain penile length. Mean age of type 3 patients at surgery was 15.8 years. Of the 7 boys 6 had previously undergone penile surgery. All required extensive scar excision and complex reconstruction involving penile skin flaps in 3, scrotal flaps in 5 and penile skin fixation in 6. Excessive suprapubic fat was removed in 5 patients, of whom 3 underwent liposuction.

RESULTS

Surgical results were uniformly good in type 1 patients except in 1 who was believed to have excessive suprapubic fat. Results were good in 14 of the 18 type 2 patients, although 2 retained excessive suprapubic fat and 2 had some unsightly scarring. No type 1 or 2 patient required additional surgery. Of the 7 type 3 patients 6 had a good result and required no additional surgery. One patient has recurrent concealed penis after 2 procedures and awaits additional surgery.

CONCLUSIONS

Concealed penis has a varied etiology and requires a flexible surgical approach. The common surgical options in all cases include complete penile degloving, excising the scarring due to previous surgery, removing excess suprapubic fat, reconstructing the penile skin with local flaps, and fixing the penile skin at the penopubic and penoscrotal angles.

Does every patient with prenatal hydronephrosis need voiding cystourethrography?

PURPOSE

Prenatal ultrasound has allowed early identification of urinary tract abnormalities that may require urological followup or early intervention. While all children with prenatal hydronephrosis should undergo ultrasound within the first few weeks of life, we believe that there is a subset of postnatal hydronephrosis for which voiding cystourethrography can be avoided if careful observation is continued.

MATERIALS AND METHODS

For 5 years 175 infants with a history of prenatal hydronephrosis were evaluated by ultrasound. Of 60 infants with less than Society for Fetal Urology grade II unilateral or bilateral hydronephrosis 44 underwent voiding cystourethrography as part of the early evaluation and 16 were observed without voiding cystourethrography. Four infants for whom we would routinely obtain voiding cystourethrography were excluded from study due to severe prenatal hydronephrosis, renal duplication, hydroureter, ipsilateral small or echogenic kidney and grade II or higher hydronephrosis.

RESULTS

Voiding cystourethrography was positive in 6 of the 40 infants (15%) with less than grade II hydronephrosis. Of these cases 3 had grade III or higher vesicoureteral reflux and 1 with high grade reflux required reimplantation. None of the 16 patients followed without voiding cystourethrography has required further evaluation or intervention. In all patients with negative or no voiding cystourethrography parenchyma was preserved and hydronephrosis stabilized or resolved.

CONCLUSIONS

Prenatal and postnatal ultrasound in infants should be used to guide further urological evaluation. Among infants with less than grade II hydronephrosis postnatally 15% had reflux on voiding cystourethrography, which is significantly higher than that reported among normal children (approximately 1%). However, none of the 16 infants observed without voiding cystourethrography on short-term antibiotic prophylaxis had deleterious renal events with 6 months to 4.5 years of followup. Therefore, we question the actual significance of the reflux detected in the first cohort of infants. Voiding cystourethrography can provide a definitive answer. However, we also believe that it is not absolutely mandatory based on the outcome in the observed group. With careful counseling and followup most patients with less than grade II hydronephrosis can be observed without urological sequela.

Congenital dorsal penile curvature: a potential problem of the long phallus

PURPOSE

We report the results of surgical correction of severe congenital dorsal penile curvature associated with a long slender phallus.

MATERIALS AND METHODS

In the last 7 years we treated 16 boys with a mean age of 2 years 10 months who had severe dorsal penile curvature. The series included 5 patients with megameatus variant hypospadias and a full foreskin, 3 who presented with hypospadias and 8 who were referred when dorsal penile curvature was noticed by the family or primary physician. Mean penile length was 6.5 cm. without stretching. In each case length was greater than 2 standard deviations above the mean for patient age. Penile circumference decreased from a mean of 4.2 cm. at the base of the shaft to 4.1 cm. at the mid shaft and 3.7 cm. at the corona. Penile circumference was generally normal for patient age until corrected for length, when it was revealed to be small. Surgical correction of severe curvature was performed in 14 patients, while 2 who presented as newborns had remarkable spontaneous improvement in the first year of life. In each case curvature was due to corporeal disproportion.

RESULTS

All patients have erections postoperatively. There has been no residual or recurrent curvature and cosmetic results are good.

CONCLUSIONS

Congenital dorsal penile curvature is a potential problem of the long phallus. In severe cases surgical repair improves the appearance of the penis but it must also address the problem of corporeal disproportion.

Prenatal urinary ascites and persistent cloaca: risk factors for poor drainage of urine or meconium

PURPOSE

The unique confluence of the urinary, genital and gastrointestinal tracts in girls with persistent cloaca potentially results in aberrant drainage of urine and meconium that may be characteristic, allowing a prenatal diagnosis to be made.

MATERIALS AND METHODS

Three of our last 15 patients with cloacal anomalies presented with urinary ascites due to intraperitoneal reflux through the genital system. In 3 female patients a long, narrow cloaca was associated with a high confluence of the urethra, vagina and rectum. All 3 patients ultimately underwent creation of a cutaneous vesicostomy.

RESULTS

In all 3 cases cutaneous vesicostomy effectively diverted urine away from the cloaca before definitive repair.

CONCLUSIONS

The urethra-like persistent cloaca may result in significant outflow resistance. When combined with high confluence, it may cause aberrant drainage of urine and/or meconium. When such problems are noted prenatally, they are likely to persist postnatally and require intervention.

Role of the renin-angiotensin system in disorders of the urinary tract

PURPOSE

The role of the renin-angiotensin system in the homeostasis of fluid, electrolyte and blood pressure has been known for quite some time. Recent developments indicate that angiotensin has a profound role, not only in the developing urinary tract but also in the response of the urinary tract to injury. In this review we outline these characteristics.

MATERIALS AND METHODS

We summarize the clinical approach to congenital abnormalities of the kidney and urinary tract, and report new data obtained in genetically engineered mice. Furthermore, we present the connection between the mutant mice observations and human congenital abnormalities.

RESULTS

Genetically engineered mutants clearly indicate that the renin-angiotensin system is important for normal renal and urological development. As in glomerular disease, the renin-angiotensin system is involved in progressive damage due to urological disease.

CONCLUSIONS

While the renin-angiotensin system is important for blood pressure regulation, it also affects the embryogenesis of the urinary tract and modulates renal injury due to specific disease processes. The importance of angiotensin and its blockade provides an exciting avenue for possible early treatment in children with congenital anomalies of the kidney and urinary tract.

Etiology, management and surgical complications of congenital chordee without hypospadias

PURPOSE

We comprehensively evaluated the etiology, management and surgical complications of chordee without hypospadias.

MATERIALS AND METHODS

We reviewed the records of patients who underwent chordee correction between January 1985 and December 1996. A total of 87 patients with a median age of 14 months were treated for chordee without hypospadias. Mean followup was 10 months. Patients were treated in the standard fashion and a straight phallus was confirmed in all postoperatively. We grouped cases according to the etiology of chordee, including skin tethering, fibrotic dartos and Buck's fasciae, corporeal disproportion and urethral tethering.

RESULTS

Of the 87 patients 28 (32%) were successfully treated with release of the skin and superficial fascia. In 29 cases (33%) extensive resection of the fibrotic dartos and Buck's fasciae was necessary to straighten the phallus, including 2 (7%) in which chordee recurred. Corporeal disproportion was identified in 24 patients (28%), of whom 2 (8%) also had complications (urethrocutaneous fistula and recurrent chordee in 1 each). In 6 cases (7%) urethral tethering was the etiology of chordee, of which 3 (50%) had complications (urethrocutaneous fistula and recurrent chordee in 2 and 1, respectively). Overall 80 of the 87 patients (92%) were successfully treated with 1 operation.

CONCLUSIONS

In our series the etiology of chordee without hypospadias was evenly divided among skin tethering, fibrotic dartos and Buck's fasciae, and corporeal disproportion. A congenitally short urethra was a rare cause of isolated chordee. Surgical correction is highly successful with a low 8% complication rate.

Ureterocystoplasty: is it necessary to detubularize the distal ureter?

PURPOSE

The conventional technique for ureterocystoplasty includes complete mobilization and incision of the ureter. We describe a modified procedure in which the distal 3 cm. of ureter are left in place and intact.

MATERIALS AND METHODS

This modification has been used in our last 13 cases of ureterocystoplasty. The first 7 patients with followup of more than a year (mean 28 months) are included in this series, and 6 have undergone video urodynamic evaluation before and after reconstruction.

RESULTS

Clinical results have been good. Four patients who have been toilet trained are continent. There have been no problems from stagnant urine in the intact ureter with only 1 case of pyelonephritis and no bladder calculi. Mean bladder capacity on cystometrogram has increased from 103 to 236 ml. after reconstruction and reached 137% of expected capacity for age and size (range 110 to 155%). No uninhibited contractions or problems with compliance have been noted.

CONCLUSIONS

The distal ureter may be left intact for ureterocystoplasty to protect ureteral blood supply. This modified technique is sound from a physiological standpoint, technically easier and associated with good results.

Natural history of refluxing distal ureteral stumps after nephrectomy and partial ureterectomy for vesicoureteral reflux

PURPOSE

We evaluated the natural history of refluxing distal ureteral stumps after nephrectomy and partial ureterectomy.

MATERIALS AND METHODS

Between 1985 to 1996, 38 patients a mean age of 37 months underwent nephrectomy and partial ureterectomy for reflux into a nonfunctioning kidney. The diagnosis included primary reflux in 23 patients, reflux associated with posterior urethral valves in 10 and ipsilateral ureterocele in 5. Mean followup was 45 months.

RESULTS

Only 1 patient with an ipsilateral ureterocele and 1 with contralateral reflux (5%) had symptomatic infections during postoperative followup, and each underwent a secondary procedure to remove the ureteral stump. No patient with only primary unilateral reflux required surgery for the refluxing stump.

CONCLUSIONS

Because of the low risk of morbidity associated with a refluxing ureteral stump, we recommend nephrectomy and proximal ureterectomy in patients with reflux into a nonfunctioning kidney.

Renal angiotensin converting enzyme promotes renal damage during ureteral obstruction

PURPOSE

We and others have shown that angiotensin II has a pivotal role in renal damage in various renal injuries. Although most angiotensin II actions are associated with the angiotensin type 1 receptor, there is increasing evidence that the angiotensin type 2 receptor also transduces some important effects of angiotensin II. In this regard we recently observed that mice with genetically engineered disruption of the angiotensin type 2 receptor, termed Agtr2 mutants, are more susceptible to structural renal damage after ureteral obstruction. Recent evidence suggests that a genetically determined increase in angiotensin converting enzyme activity in humans promotes end organ damage. Therefore, we determined whether renal damage in Agtr2 mutants is associated with heightened angiotensin converting enzyme activity.

MATERIALS AND METHODS

We studied 28 wild type and 19 Agtr2 mutant mice with unilateral ureteral obstruction. Seven days after obstruction was created serum samples were obtained to evaluate angiotensin converting enzyme activity. The obstructed and contralateral kidneys were harvested for histological analysis and determination of renal angiotensin converting enzyme activity by high pressure liquid chromatography.

RESULTS

Renal angiotensin converting enzyme was uniformly higher than serum angiotensin converting enzyme in normal wild type and Agtr2 mutant mice. However, even at baseline Agtr2 mutant mice had strikingly higher renal angiotensin converting enzyme activity than normal wild type mice (mean plus or minus standard error 1,492+/-83 versus 450+/-60 milliunits per gm. tissue weight, p <0.0005). Histological analysis revealed more extensive parenchymal damage in the obstructed kidneys of mutant mice than in identically treated controls. Notably while unilateral ureteral obstruction decreased renal angiotensin converting enzyme activity in each group, activity remained persistently higher in the Agtr2 mutants than in normal mice (mean 742+/-146 versus 310+/-43 milliunits per gm. tissue weight, p <0.005).

CONCLUSIONS

We propose that elevated renal angiotensin converting enzyme activity contributes to more severe renal parenchymal damage in ureteral obstruction by promoting the availability of growth factors, such as angiotensin II, or depleting antiproliferation factors, such as bradykinin or nitric oxide. These findings complement previous observations that angiotensin converting enzyme inhibition preserves the renal parenchyma after injury, including obstruction.

Ureterocystoplasty: is it necessary to detubularize the distal ureter?

PURPOSE

The conventional technique for ureterocystoplasty includes complete mobilization and incision of the ureter. We describe a modified procedure in which the distal 3 cm. of ureter are left in place and intact.

MATERIALS AND METHODS

This modification has been used in our last 13 cases of ureterocystoplasty. The first 7 patients with followup of more than a year (mean 28 months) are included in this series, and 6 have undergone video urodynamic evaluation before and after reconstruction.

RESULTS

Clinical results have been good. Four patients who have been toilet trained are continent. There have been no problems from stagnant urine in the intact ureter with only 1 case of pyelonephritis and no bladder calculi. Mean bladder capacity on cystometrogram has increased from 103 to 236 ml. after reconstruction and reached 137% of expected capacity for age and size (range 110 to 155%). No uninhibited contractions or problems with compliance have been noted.

CONCLUSIONS

The distal ureter may be left intact for ureterocystoplasty to protect ureteral blood supply. This modified technique is sound from a physiological standpoint, technically easier and associated with good results.

Feminizing genitoplasty: state of the art

Surgical management of intersex states continues to evolve such that today's efforts achieve near normal cosmetic and functional results. In this article we discuss the reconstruction of the female genitalia in those that have had significant androgen stimulation as well as those with near normal external genitalia but significant urogenital sinus anomalies. The initial evaluation as well as postoperative follow-up management is addressed.

Rabbit urethral regeneration using small intestinal submucosa onlay grafts

OBJECTIVES

To determine if small intestinal submucosa (SIS) can evoke urethral regeneration.

METHODS

Twenty male white New Zealand rabbits were assigned to one of three experimental groups. Group 1 (n = 4) underwent simple urethrotomy and closure. Group 2 (n = 8), a second control group, underwent an onlay urethroplasty with a graft of full-thickness preputial skin from the host rabbit. Group 3 (n = 8) underwent an onlay urethroplasty with an SIS graft.

RESULTS

All eight SIS onlay grafts promoted regeneration of the normal rabbit epithelium supported by a well-vascularized collagen and smooth muscle backing. Preputial free onlay grafts maintained a keratinizing squamous cell epithelium with a poor supportive backing, which resulted in the formation of urethral diverticulum.

CONCLUSIONS

SIS onlay patch grafts for urethroplasty promote rabbit urethral regeneration.

Genital malformations and coexistent urinary tract or spinal anomalies in patients with imperforate anus

PURPOSE

Urinary tract malformations have been described in up to 50% of patients with imperforate anus but genital anomalies have been less well analyzed in the same patient population. We sought to evaluate the frequency of coexisting genital, urinary and spinal malformations in a population with imperforate anus.

MATERIALS AND METHODS

We reviewed 128 cases of imperforate anus, focusing on genital malformations and their relationship to anomalies of the urinary tract and spine. The series included 69 boys and 59 girls with low (59), intermediate (22) and high (47) imperforate anus.

RESULTS

Boys were much more likely to have a genital or upper urinary tract problem than girls (26 or 50 versus 5 or 30%, respectively). The risk for both sets of problems increased with the level of the anorectal lesion. The incidence of genital malformations increased from 14 to 26% in the presence of a renal lesion and from 10 to 23% with an associated spinal problem. Conversely, the incidence of urinary and spinal anomalies increased in patients with genital malformations.

CONCLUSIONS

The genitalia of children with imperforate anus should be carefully examined. Patients with anorectal malformations should also be evaluated for urinary tract and spinal problems. The yield of such studies increases in patients with recognized genital malformations.

Management of ectopic ureters: experience with the upper tract approach

PURPOSE

The necessity of removing the ureteral stump after upper tract surgery for an ectopic ureter has been debated. We reviewed the records of patients initially treated at the kidney level to evaluate indications for later stump removal.

MATERIALS AND METHODS

We reviewed the medical records of 32 patients with 33 ectopic ureters treated at the kidney level during the last 10 years.

RESULTS

Ectopic ureters were associated with duplicated collecting systems in 31 cases and with single systems in 2. Upper pole heminephrectomy and partial ureterectomy were performed in 23 units and upper tract reconstruction was done in 8. Both patients with single systems underwent nephrectomy. Four patients (12%) required repeat surgery at the bladder level, including 1 who underwent ureteral reimplantation for persistent ipsilateral lower pole reflux and simultaneous upper pole stump removal. Preoperative voiding cystourethrography revealed reflux into the ectopic ureter in 1 patient with postoperative reflux and infections. The remaining 2 patients required a repeat operation to remove the stump due to recurrent urinary tract infections and newly detected reflux into the stump, respectively.

CONCLUSIONS

The majority of patients with ectopic ureters can be treated by addressing only the upper urinary tract. No patient who presented with incontinence required ureteral stump removal. Whether noted preoperatively or postoperatively, reflux into the ectopic ureter necessitated ureteral stump removal. Three of the 6 patients (50%) who had reflux to the ipsilateral kidney required lower tract surgery.

Reconstruction of the high urogenital sinus: early perineal prone approach without division of the rectum

PURPOSE

Reconstruction of the vagina and external genitalia in the infant is quite challenging, particularly when a urogenital sinus is associated with high confluence of the vagina and urethra. Many surgeons believe that children with such a malformation should undergo staged or delayed reconstruction, so that vaginoplasty is done when the child is older and larger. Vaginoplasty early in life is thought to be difficult due to patient size and poor visualization. The posterior sagittal approach has been beneficial for acquiring exposure to high urogenital sinus anomalies but it has been thought to require splitting of the rectum and temporary colostomy. We report a modification of this technique.

MATERIALS AND METHODS

In the last 5 years all patients with urogenital sinus anomalies underwent reconstruction using a single stage approach regardless of the level of confluence. In 8 patients with a high level of confluence reconstruction was performed using a perineal prone approach. Exposure was achieved without division of the rectum. The operative technique is presented in detail.

RESULTS

This midline perineal prone approach has allowed excellent exposure of the high vagina even in infants. In all 8 patients reconstruction was done without difficulty and no patient required incision of the rectum or colostomy. This procedure did not preclude the use of a posteriorly based flap for vaginal reconstruction.

CONCLUSIONS

While patients with low confluence can be treated with single posteriorly based flap vaginoplasty, those with higher confluence may benefit from a perineal prone approach to achieve adequate exposure for pull-through vaginoplasty. This prone approach to the high urogenital sinus anomaly can be performed without division of the rectum, provides excellent exposure of the high confluence even in small children and does not preclude the use of posterior flaps for vaginal reconstruction.

Upsizing of the artificial urinary sphincter cuff to facilitate spontaneous voiding

OBJECTIVES

Following placement of an artificial urinary sphincter (AUS) in the male child, functional and mechanical alterations can ensue, resulting in an inability to void spontaneously. One possible mechanical etiology in the patient entering puberty is prostatic growth within the fixed mechanical confines of the AUS cuff, resulting in progressive bladder outlet obstruction. Unrecognized infravesical obstruction can, in turn, lead to upper urinary tract deterioration, sepsis, or renal failure. We evaluated the effect of somatic growth and maturation of the male urethra on voiding dynamics in boys with an AUS to specifically determine whether revision of the sphincter cuff (ie, upsizing) is beneficial in restoring the ability to void spontaneously.

METHODS

A retrospective review of 124 children with an AUS was performed. Eleven boys were identified whose bladder neck cuffs were later upsized in an attempt to improve bladder emptying. All boys were prepubertal at the time of original cuff placement. The average interval between the initial operation and cuff upsizing was 5 years.

RESULTS

Following original sphincter placement, 8 patients emptied to completion spontaneously and 3 patients emptied by intermittent catheterization. All eight of the spontaneous voiders experienced progressive difficulty emptying after they entered puberty and ultimately had to rely on clean intermittent catheterization to empty completely. Follow-up subsequent to cuff exchange averaged more than 5 years (range 1 to 10 years). Despite an average increase of 10 mm in cuff size, all patients continued to depend on intermittent catheterization to empty completely.

CONCLUSIONS

Upsizing the bladder cuff in the maturing male who experiences difficulty with bladder emptying does not restore the ability to void spontaneously.

Principles in management of complex pediatric genitourinary plexiform neurofibroma

Neurofibromatosis is a hamartomatous disorder of neural crest derivation characterized by cutaneous pigmentation and tumor formation in various tissues. Visceral involvement is typically insidious, progressive, and difficult to treat. Plexiform neurofibroma of the urinary tract is rare. Involvement of nearly every genitourinary structure by these lesions has been reported, with the bladder being most commonly involved. In part due to the small number of patients seen at any one institution and the highly variable location and extent of this disease process, a plan for management of individuals with genitourinary neurofibromatosis has not been proposed. In an attempt to define specific goals in treatment of such patients, we reviewed our population of 260 pediatric patients with type 1 neurofibromatosis. We present our series of 5 patients with complex genitourinary lesions and describe specific management principles.