Ectopic Insertion Research Articles

Ectopic vaginal insertion of an obstructed duplicated ureter in an adult female: demonstration by magnetic resonance imaging

The usual presentation of an ectopically inserted vaginal ureter is continuous dribbling of urine in an otherwise healthy girl. This case did not present with the usual symptomatology, as there was severe stenosis of the ectopically located ureteric orifice. Conventional imaging failed to show the vaginal insertion of an ectopic ureter. However, a magnetic resonance urogram readily depicted the collecting system from the kidney to the point of ureteric insertion.

Successful surgical correction of true diphallia, scrotal duplication, and associated hypospadias

A 1-year-old child with complete duplication of penis presented with continuous dribbling of urine. Examination revealed hypospadias of 1 penis and a duplicated scrotum with 2 normal testes. Cystourethrogram revealed a single bladder with a normal urethra in the dorsally placed phallus and ectopic insertion into the bladder of the ventral urethra. Abnormality was corrected by excision of the ventrally located penis bearing the ectopic urethra. The preputial skin of this ventral penis was used to repair the hypospadias of the dorsal penis. The case is being reported in view of its rarity and the successful surgical correction.

The Shwachman-Bodian-Diamond syndrome gene encodes an RNA-binding protein that localizes to the pseudopod ofDictyosteliumamoebae during chemotaxis

The Shwachman-Bodian-Diamond syndrome (SBDS) is an autosomal disorder with multisystem defects. The Shwachman-Bodian-Diamond syndrome gene (SBDS), which contains mutations in a majority of SBDS patients, encodes a protein of unknown function, although it has been strongly implicated in RNA metabolism. There is also some evidence that it interacts with molecules that regulate cytoskeletal organization. Recently, it has been demonstrated by computer-assisted methods that the single behavioral defect of polymorphonuclear leukocytes (PMNs) of SBDS patients is the incapacity to orient correctly in a spatial gradient of chemoattractant. We considered using the social amoeba Dictyostelium discoideum, a model for PMN chemotaxis, an excellent system for elucidating the function of the SBDS protein. We first identified the homolog of SBDS in D. discoideum and found that the amino acids that are altered in human disease were conserved. Given that several proteins involved in chemotactic orientation localize to the pseudopods of cells undergoing chemotaxis, we tested whether the SBDS gene product did the same. We produced an SBDS-GFP chimeric in-frame fusion gene, and generated transformants either with multiple ectopic insertions of the fusion gene or multiple copies of a non-integrated plasmid carrying the fusion gene. In both cases, the SBDS-GFP protein was dispersed equally through the cytoplasm and pseudopods of cells migrating in buffer. However, we observed differential enrichment of SBDS in the pseudopods of cells treated with the chemoattractant cAMP, suggesting that the SBDS protein may play a role in chemotaxis. In light of these results, we discuss how SBDS might function during chemotaxis.

Dribbling of Urine due to Ectopic Vaginal Insertion of an Upper Pole Ureter Diagnosed by Magnetic Resonance Urography

Imaging the urinary tract in children has been mainly based on ultrasound (US) and intravenous pyelography (IVP), but these imaging modalities rarely show ectopic insertion of the ureter and the condition is often under diagnosed due to unusual clinical presentations. Recently newer magnetic resonance urography sequences have been developed that provide better delineation of the urinary tract. We report a 3-year-old girl presenting continuous dribbling of urine in which magnetic resonance urography revealed ectopic vaginal insertion of the ureter.

Parameters determining the efficiency of gene targeting in the moss Physcomitrella patens.

In the moss Physcomitrella patens, transforming DNA containing homologous sequences integrates predominantly by homologous recombination with its genomic target. A systematic investigation of the parameters that determine gene targeting efficiency shows a direct relationship between homology length and targeting frequency for replacement vectors (a selectable marker flanked by homologous DNA). Overall homology of only 1 kb is sufficient to achieve a 50% yield of targeted transformants. Targeting may occur through homologous recombination in one arm, accompanied by non-homologous end-joining by the other arm of the vector, or by allele replacement following two homologous recombination events. Allele replacement frequency depends on the symmetry of the targeting vector, being proportional to the length of the shorter arm. Allele replacement may involve insertion of multiple copies of the transforming DNA, accompanied by ectopic insertions at non-homologous sites. Single-copy and single insertions at targeted loci (targeted gene replacements, ‘TGR’) occur with a frequency of 7–20% of all transformants when the minimum requirements for allele replacement are met. Homologous recombination in Physcomitrella is substantially more efficient than in any multicellular eukaryote, recommending it as the outstanding model for the study of homologous recombination in plants.

Dispersal and Evolution of the Sinorhizobium meliloti Group II RmInt1 Intron in Bacteria that Interact with Plants

Group II introns are both self-splicing RNAs and mobile retroelements found in bacterial and archaeal genomes and in organelles of eukaryotes. They are thought to be the ancestors of eukaryote spliceosomal introns and non-long terminal repeat retrotransposons. We show here that RmInt1, a bacterial group II intron first described in the nitrogen-fixing symbiont of alfalfa (Medicago sativa) Sinorhizobium meliloti, is also present in other Sinorhizobium and Rhizobium species. The intron-homing sites in these species are IS elements of the ISRm2011-2 group as in S. meliloti, but ectopic insertion is also observed. We present evidence that these related bacteria have acquired RmInt1 by vertical inheritance from a common ancestor and by independent horizontal transfer events. We also show that RmInt1 is mobile in related taxa of bacteria that interact with plants and tends to evolve toward an inactive form by fragmentation, with loss of the 3' terminus including the intron-encoded protein. Our results provide an overview of the evolution and dispersion of a bacterial group II intron.

ECTOPIC OPENING OF THE COMMON BILE DUCT INTO THE PYLORIC CHANNEL

Ectopic opening of the common bile duct is extremely rare. There are scant reports in the literature describing ectopic bile duct insertion, and the clinical implication of this finding is unclear. We describe a case of the common bile duct (CBD) opening into the pyloric channel. A previously healthy 47-year-old male presented with a 3 day history of right upper quadrant abdominal pain, fever, nausea and vomiting. On examination, he was febrile to 104°F, icteric, and tender to palpation of the right upper quadrant. Labs revealed leukocytosis with a left shift (WBC 11,100 and 93% PMN) and cholestasis with mild transaminitis (total bilirubin 4.9, direct bilirubin 2.7, alkaline phosphatase 211, ALT 140 and AST 212). Imaging showed mild CBD dilatation and gallstones within a gallbladder that had wall thickening and pericholecystic fluid. The patient was resuscitated with IV fluids and antibiotics with some improvement. The patient underwent ERCP for suspected choledocholithiasis and possible cholangitis. No papilla could be found after extensive examination of the duodenal wall during ERCP. The duodenoscope was withdrawn and a front-viewing endoscope was inserted. A small slit-like opening of the CBD was identified within the pyloric channel. The opening was cannulated using a standard catheter. Cholangiogram confirmed it was the CBD and revealed several small filling defects within a normal appearing CBD. While most of the filling defects were thought to be air bubbles, small stones cannot be ruled out. Due to the location of the opening, sphincterotomy cannot be performed and a biliary stent was inserted for drainage. The pancreatic duct could not be cannulated, and no separate opening for the pancreatic duct was found. The patient's symptoms subsequently resolved and he was later taken for cholecystectomy. Our case demonstrates an opening of the CBD into the pyloric channel. Other sites of bile duct insertion that have been described include the stomach, duodenal bulb, third and fourth portions of the duodenum. Clinical implications of these anomalous sites of insertion are not known. Some authors suggest these openings are at higher risk for biliary disease based on altered duct anatomy and lack of sphincter of Oddi function. In addition, when biliary disease occurs it may be more difficult to treat due to altered anatomy.

Sonographic diagnosis of urethral anomalies in infants: value of perineal sonography.

To assess the value of urethral sonography including a perineal approach in evaluating urethral anomalies in infants. A radiology database review identified 88 patients (mean age +/- SD, 64 +/- 84 days) who underwent voiding cystourethrography (VCUG) and urethral sonography as part of extended sonography of the urinary tract. Sonographic and VCUG images and reports were reviewed to assess agreement between both modalities for detection of urethral anomalies. Sonography facilitated the correct diagnosis of all 3 posterior urethral valves. The only urethral diverticulum, the only ectopic ureteric insertion into the urethra, the only urogenital sinus, and the only urethrovaginal fistula were also shown on sonography. In 73 (94%) of 78 cases, sonography correctly showed the absence of anomalies. In 5 infants, sonography could not reliably assess the urethra and showed indirect signs of urethral anomalies; however, these patients had normal urethras on VCUG. Our data show that sonography of the urethra is a valuable tool for diagnosis of urethral anomalies. Especially, negative findings on sonography are highly suggestive of the absence of urethral anomalies. Positive or equivocal sonographic findings should indicate VCUG.

Ectopic intra-aortic insertion of a subclavian central venous catheter: case report and review of the literature

Clinical Summary A 70-year-old Saudi female patient with a known case of end-stage renal disease had been receiving regular hemodialysis for the last 6 years. She underwent left subclavian venous catheter insertion as a temporary form of access. During dialysis through the catheter, the attending nurse observed a very good flow to the machine but high resistance back to the circulation. An ectopic intra-arterial insertion of the catheter was suspected. Angiography through the catheter showed the tip of the catheter inside the aortic arch (Figure 1). Computed tomographic scanning confirmed the intraaortic position of the catheter, with the point of entry at the root of the left common carotid artery (Figure 2). The patient underwent median sternotomy, removal of the catheter from the aortic arch, and closure of the entry site with a 2-0 Prolene suture (Ethicon, Inc, Somerville, NJ). The patient did well after the operation, the chest tube was removed on the third postoperative day, and the patient was discharged home after 10 days without complication.

New shuttle vectors for ectopic insertion of genes into Bacillus subtilis

We have constructed shuttle vectors for integration of genes via double homologous recombination into three ectopic sites on the chromosome of Bacillus subtilis. The sites of integration are the pyrD, gltA, and sacA genes located at 139°, 172°, and 333°, respectively, on the chromosome. Integration of the vectors into the target genes leads to antibiotic resistance as well as different metabolic phenotypes. B. subtilis strains with integrations of the empty vectors were able to sporulate at rates comparable to wild type cells. Similar levels of expression were obtained from constitutive lacZ fusions integrated at the different sites.

MAGNETIC RESONANCE UROGRAPHY: A NEW GOLD STANDARD FOR THE EVALUATION OF SOLITARY KIDNEYS AND RENAL BUDS?

We evaluated the diagnostic potential of magnetic resonance urography (MRU) in pediatric patients with a solitary kidney and/or dysplastic orthotopic or ectopic renal buds. We present our evolving experience with this imaging procedure. A total of 30 patients with a mean age of 43.8 months with a known or suspected solitary kidney with or without clinical symptoms underwent ultrasound of the urinary tract as well as voiding cystourethrogram, renal static dimercapto-succinic acid (DMSA) scintigraphy and MRU. The results of these diagnostic imaging studies were then compared with each other and set against the results of the final diagnosis established at surgery and by histology, if available. Dysplastic orthotopic or dystopic renal buds suspected on ultrasound in 11 of the 30 patients were confirmed in all 11 by MRU. While accompanying ectopic ureteral insertions were shown in only 3 patients by ultrasound, they were visualized in all 4 by MRU. The other 7 patients with dysplastic renal buds had orthotopic ureteral orifices. DMSA scintigraphy failed to detect 10 renal buds. The diagnostic value of MRU appears to be superior to that of other imaging tests, even to that of DMSA scintigraphy, which with voiding cystourethrography is currently considered the gold standard for evaluating sonographically suspected solitary kidneys with contralateral orthotopic or ectopic renal buds and ectopic ureteral insertion.

Accuracy of cystoscopy in the diagnosis of ureteral injury in benign gynecologic surgery.

Our objective was to review our experience and attempt to identify risk factors for ureteral injury during gynecologic surgery for benign conditions. A retrospective chart review was performed of all cases of ureteral injury during gynecologic surgery for benign conditions, at Temple University Hospital, from January 1992 to September 2002. We analyzed hospital records to determine whether the injury was diagnosed intraoperatively, with postprocedure cystoscopy, or if cystoscopy was ineffective in diagnosing the injury. There were nine ureteral injuries during the study period. Of these, two were diagnosed during the procedure, two were discovered by immediate postprocedure cystoscopy, and the other five were discovered during the postoperative period. Of these five, three patients had immediate postprocedure cystoscopy and the injuries were not detected. Risk factors associated with ureteral injury included: a large uterus (5), high-grade cystocele (3), ectopic insertion of the ureter into the bladder (1), and previous surgeries (4). Our conclusion was that negative cystoscopy cannot be solely relied on to rule out ureteral injury, as cases with partial obstruction and ureteral patency can be missed.

By-products of immunoglobulin somatic hypermutation.

The antigen receptor loci are the only loci in humans to undergo programmed somatic gene modification. Although aberrant V(D)J integration and class switch recombination can both give rise to chromosomal translocations, a role for somatic hypermutation in such genomic rearrangements has been suggested but is less clearly established. To characterize the types of by-products of somatic hypermutation, we analyzed aberrant rearrangements involving the immunoglobulin loci in a human B-cell line (Ramos) that performs Ig V gene hypermutation constitutively during culture. Single-nucleotide substitutions account for 95% of the mutational events in the VH gene, with small deletions and duplications accounting for most of the remaining mutations. However, larger genetic alterations can be detected at low frequency, accounting for 0.5% of VH-inactivating mutations. Examples include a large (13 kb) deletion, which entirely removes the expressed VH gene; a 3-kb deletion extending from the functional VHDJH into an upstream VH (generating a hybrid VHDJH gene reminiscent of VH replacement); and an ectopic insertion into the VH from chromosome 1. The results support the proposal that aberrant antibody hypermutation can lead to gross genomic alterations but indicate that such events are rare.

Anomalies of the distal ureter, bladder, and urethra in children: embryologic, radiologic, and pathologic features.

Congenital anomalies of the lower urinary tract are a significant cause of morbidity in infancy. Radiologic investigation is an important source of clinical information in lower urinary tract disorders but should not inconvenience the patient, expose the patient to unnecessary radiation, or delay surgical correction. In pediatric patients with suspected underlying urologic structural anomalies, screening ultrasonography is commonly the initial diagnostic study. If dilatation of the urinary tract is confirmed, voiding cystourethrography is performed to determine the presence of vesicoureteral reflux (VUR) and other causes of upper tract dilatation. If VUR is confirmed, follow-up with nuclear cystography or echo-enhanced cystosonography may be performed. If VUR is excluded, nuclear diuresis renography is the primary test for differentiating between obstructed and nonobstructed megaureter. Intravenous urography can be used to specifically identify an area of obstruction and to determine the presence of duplex collecting systems and a ureterocele. Computed tomography and magnetic resonance (MR) imaging are unsuitable for general screening but provide superb anatomic detail and added diagnostic specificity. MR imaging is mandatory in the evaluation of associated spinal anomalies. MR urography can demonstrate ectopic extravesical ureteric insertions, thereby providing a global view of the malformation. Familiarity with anomalies of the lower urinary tract is essential for correct diagnosis and appropriate management.

Post‐transcriptional Silencing of the Tomatinase Gene in Fusarium oxysporum f. sp lycopersici

Abstract Fusarium oxysporum f. sp. lycopersici produces an extracellular enzyme tomatinase, which has been known to detoxify α‐tomatine, a preformed inhibitor of fungal growth in tomato plants. To understand the role of the tomatinase in pathogenicity, we performed transformation‐mediated disruption of the tomatinase gene in F. oxysporum f. sp. lycopersici. Mutants obtained showed increase in sensitivity to α‐tomatine and decrease in tomatinase activity in vitro. Inoculation assay showed reduced pathogenicity of the mutants on tomato plants, suggesting an important role of tomatinase in pathogenicity of this fungus. However, Southern blot analysis revealed that the resident tomatinase gene of the mutants was not disrupted but the gene replacement vector was ectopically integrated into the genome of the mutants. To clarify the mechanisms involved, we examined one of the ectopic insertion mutants at both DNA and RNA levels. No methylation of the resident tomatinase gene was detected. Northern blot analysis revealed low level of the tomatinase gene expression and also the presence of antisense RNA in the ectopic mutant. Thus, post‐transcriptional gene silencing seems to be involved in the suppression of tomatinase in the ectopic mutant.

Non-cognate template usage and alternative priming by a group II intron-encoded reverse transcriptase

Group II introns are retroelements that site-specifically insert into DNA through homing. They are also implicated in related phenomena such as ectopic site insertions and precise intron deletions, but little is known about how group II intron reverse transcriptases (RTs) interact with non-cognate substrates. Here we show that wild-type aI2 RT readily reverse transcribes non-cognate RNAs in mitochondrial RNP particles when the aI2 intron structure is misfolded. In two closely related priming mutants, 1°2 ΔD5 and 1 +2 ΔD5, which contain wild-type RT but a disrupted intron structure, the RT has substantially lost specificity for aI2 RNA and copies multiple RNAs present in the RNP particles, using an alternative priming mechanism. The RT in 1°2 ΔD5 RNP particles can also copy exogenous RNAs but unlike the endogenous templates, a complementary primer is required, suggesting that the alternative priming event is specific to RT-RNA interactions formed in vivo. Alternatively primed cDNAs from strains 1°2 ΔD5, 1 +2 ΔD5 and 1°2 P714T (containing the mutation P714T in the RT) do not use homing site DNA as a primer, but appear to utilize a non-complementary DNA primer of approximately ten nucleotides. The alternative priming mechanism and reverse transcription of non-cognate templates has implications for in vivo reverse transcription of non-intronic RNAs, which is expected to occur during intron deletions and other retroprocessing events.

Elevated levels of intrachromosomal homologous recombination in Arabidopsis overexpressing the MIM gene.

The Arabidopsis MIM gene encodes a protein belonging to the SMC family (structure maintenance of chromosomes) which is required for intrachromosomal homologous recombination (ICR). Both ICR and MIM gene expression are enhanced by DNA-damaging treatments, suggesting that MIM is a factor limiting DNA repair by homologous recombination (HR) under genotoxic stress. We tested this hypothesis by measuring the levels of recombination in the mim mutant under genotoxic stress, using methyl methanesulfonate. Although the mutant clearly showed diminished basal and induced levels of ICR, enhancement of ICR by DNA-damaging treatments was similar to that observed in the wild type. This suggests that the MIM gene product is required for DNA repair by HR, but is not critical for HR induction. To determine whether enhanced availability of MIM would increase basal HR levels in Arabidopsis, we examined ICR frequencies in transgenic Arabidopsis strains overexpressing the MIM gene after ectopic insertion of additional MIM copies. Two independent lines showed a twofold increase in ICR frequency relative to the wild type. Thus MIM is required for efficient ICR in plants, and its manipulation can be used to change homologous recombination frequencies. Since MIM is one of the components responsible for chromatin dynamics, our results suggest that the chromatin environment determines the frequency of homologous recombination.

The management of children with complete ureteric duplication: selective use of uretero-ureterostomy as a primary and salvage procedure.

To determine the optimum management of duplex urinary tracts with refluxing or obstructed units. Sixty-three children (19 boys and 44 girls) with complete duplex-system anomalies (84 duplex system units) who underwent corrective surgery by one surgeon (H.C.) between March 1983 and June 1997 were reviewed, analysing their diagnosis and treatment. Most children had presented with urinary tract infection; a ureterocele was found in 26 renal units, reflux in 12 and a combined anomaly in 18. Ectopic insertion of the ureter causing incontinence was found in six and ureteric obstruction in nine ureteric units. Patients were managed so that whenever possible, functional renal tissue was preserved; thus surgical strategies were basically staged, conservative, and planned preoperatively on the basis of renal function. Initial surgery was undertaken in 71 units (all patients; ureterocele incision in 12, upper pole nephrectomy in 30, ureteric reimplantation in 14, uretero-ureterostomy in 13 and others in two). The median (range) follow-up was 7.6 (2.1-16) years. Secondary procedures were undertaken in 24 units (34%); ureterocele incision (11 of 12 units) was the most common procedure of additional surgery, followed by ureteric reimplantation (six of 27 units), upper pole nephrectomy (eight of 37 units) and uretero-ureterostomy (two of 18 units). Uretero-ureterostomy was the most successful nephron-sparing additional operation. When the upper pole is salvageable, uretero-ureterostomy may be the preferred alternative for managing complete duplex system anomalies.

Laparoscopy as the investigation and treatment of choice for urinary incontinence caused by small 'invisible' dysplastic kidneys with infrasphincteric ureteric ectopia.

To report our experience of using laparoscopy for the accurate location and simultaneous removal of small dysplastic kidneys with ectopic ureteric insertion causing urinary incontinence and that were not detected by conventional imaging modalities. Seven girls (mean age 7.9 years, range 3.5-13) presented with urinary leakage occurring between normal voids. Imaging studies including ultrasonography, renal scintigraphy, intravenous urography, computed tomography and/or magnetic resonance imaging in six of the seven patients revealed a single normal functioning kidney, but failed to detect the contralateral nonfunctioning dysplastic kidney. All patients were examined under anaesthesia, followed by transperitoneal laparoscopy for the simultaneous localization and removal of the dysplastic kidneys under the same setting. Laparoscopy in all seven patients revealed a small dysplastic kidney that could always be easily located by first finding the draining ureter over the iliac vessels and then following it upwards. Four dysplastic kidneys were found in the renal fossa (two left, two right). One kidney was found at the left iliac fossa just above the pelvic brim, one at the left lumbar region, and the other at the right iliac fossa. Laparoscopic nephroureterectomy was successful in all seven girls and the patients were discharged 48 h after surgery. The follow-up (mean 2.7 years, range 3 months-5.4 years) showed excellent cosmetic results and all the patients have remained completely dry. In patients with a classical picture of urinary incontinence caused by infrasphincteric ureteric ectopia associated with a small nonfunctioning kidney, video-laparoscopy, with its magnifying effect, can reliably confirm the diagnosis, locate the dysplastic kidney and allow its removal in the same setting. We propose that laparoscopy should be considered the investigation and treatment of choice in such patients, and should be undertaken without delay even if the dysplastic kidney or the ectopic ureteric orifice cannot be identified with all other conventional means.

The boundaries of the silenced HMR domain in Saccharomyces cerevisiae.

The chromosomes of eukaryotes are organized into structurally and functionally discrete domains that provide a mechanism to compact the DNA as well as delineate independent units of gene activity. It is believed that insulator/boundary elements separate these domains. Here we report the identification and characterization of boundary elements that flank the transcriptionally repressed HMR locus in the yeast Saccharomyces cerevisiae. Deletion of these boundary elements led to the spread of silenced chromatin, whereas the ectopic insertion of these elements between a silencer and a promoter blocked the repressive effects of the silencer on that promoter at HMR and at telomeres. Sequence analysis indicated that the boundary element contained a TY1 LTR, and a tRNA gene and mutational analysis has implicated the Smc proteins, which encode structural components of chromosomes, in boundary element function.