The long-term culture of porcine urothelial cells and induction of urothelial stratification

OBJECTIVE

To assess porcine urothelial cell cultures and the in vitro induction of urothelial stratification in long-term cultures, to study their morphological, functional and genetic behaviour, and thus provide potential autologous urothelium for tissue-engineered substitutes for demucosalized gastric or colonic tissue.

MATERIALS AND METHODS

Primary cultures of porcine urothelium were established and the cells passaged thereafter. Cell specificity was confirmed by cytokeratin analysis, cell membrane stability assessed using lactate dehydrogenase leakage, cell de-differentiation by gamma-glutamyl transferase activity and genomic stability by karyotype investigations. Histology and scanning electron microscopy were performed to study the cultured cells and the stratified constructs. Furthermore, collagen matrices were tested as cell scaffolds.

RESULTS

The cells were cultured for 180 days; 10 subcultures were established during this period. Stratification was induced in a culture flask and on a collagen matrix. Cytokeratins 7, 8, 17 and 18 were expressed in all cultures, and cell membranes were stable, with no evident de-differentiation. The cultures were stable in their genotype and no chromosomal aberrations were found. The histology and immunohistochemistry of the stratified porcine constructs, and cell membrane stability and cell de-differentiation, were compared with those in the human system.

CONCLUSION

Pig and human urothelial cells can be cultured over a long period with no signs of senescence. Urothelial stratification can be induced in vitro. The collagen matrix seems to be an excellent scaffold, allowing cell adherence and growth.

Evaluation of six commercial tests and the germ-tube test for presumptive identification of Candida albicans

Six commercial tests (Albicans ID, bioMérieux, France; CandiSelect, Sanofi Diagnostics Pasteur, France; CHROMagar Candida, Becton Dickinson, USA; Fluoroplate Candida, Merck, Germany; Fongiscreen 4H, Sanofi Diagnostics Pasteur; and Murex Candida albicans, Murex Diagnostics, USA) and the germ-tube test for presumptive identification of Candida albicans were evaluated using clinical isolates of Candida albicans (n = 350) and of non-albicans yeasts (n = 135). Sensitivities and specificities of all tests regarding the identification of Candida albicans were greater than 97%. The two tests that also allow presumptive identification of some non-albicans yeasts (CHROMagar Candida and Fongiscreen 4H) did not identify all isolates of Candida glabrata and Candida tropicalis. In addition, CHROMagar Candida identified as Candida glabrata some isolates belonging to different species of non-albicans yeasts.

The exstrophy-epispadias complex in the duplicated lower urinary tract

PURPOSE

The exstrophy-epispadias complex in combination with a duplicated lower urinary tract is an extremely rare congenital malformation. We describe 2 cases of bladder exstrophy in association with a duplicated lower urinary tract.

MATERIALS AND METHODS

We analyzed the case histories of 2 patients. The first case had anteroposterior duplication of the bladder communicating through an isthmus and a duplicate urethra. The anterior system was exstrophic and epispadiac. The second case had a duplicate bladder without epispadias. There was a communication between the anterior exstrophic and posterior normal bladders. No other malformations were present.

RESULTS

Both patients underwent excision of the duplicate exstrophic bladder in conjunction with primary closure of the abdominal wall. Postoperative continence was normal. Histological examination confirmed the diagnosed bladder duplication.

CONCLUSIONS

Although duplication of the lower urinary tract in combination with the exstrophy-epispadias complex is extremely rare, all children presenting with an exstrophic bladder and a normal urethra alone or in association with an epispadiac anterior urethra should be evaluated for a bladder duplication with possible isthmic communication.

Two amyloid precursor protein transgenic mouse models with Alzheimer disease-like pathology

Mutations in the amyloid precursor protein (APP) gene cause early-onset familial Alzheimer disease (AD) by affecting the formation of the amyloid beta (A beta) peptide, the major constituent of AD plaques. We expressed human APP751 containing these mutations in the brains of transgenic mice. Two transgenic mouse lines develop pathological features reminiscent of AD. The degree of pathology depends on expression levels and specific mutations. A 2-fold overexpression of human APP with the Swedish double mutation at positions 670/671 combined with the V717I mutation causes A beta deposition in neocortex and hippocampus of 18-month-old transgenic mice. The deposits are mostly of the diffuse type; however, some congophilic plaques can be detected. In mice with 7-fold overexpression of human APP harboring the Swedish mutation alone, typical plaques appear at 6 months, which increase with age and are Congo Red-positive at first detection. These congophilic plaques are accompanied by neuritic changes and dystrophic cholinergic fibers. Furthermore, inflammatory processes indicated by a massive glial reaction are apparent. Most notably, plaques are immunoreactive for hyperphosphorylated tau, reminiscent of early tau pathology. The immunoreactivity is exclusively found in congophilic senile plaques of both lines. In the higher expressing line, elevated tau phosphorylation can be demonstrated biochemically in 6-month-old animals and increases with age. These mice resemble major features of AD pathology and suggest a central role of A beta in the pathogenesis of the disease.

Endoscopic management of ureteroceles in children

OBJECTIVE

Treatment of ureteroceles in children varies according to the anatomicopathological form and the choice of the surgical team. This study tries to determine the exact value of the endoscopic management of ureteroceles in children.

METHODS

Between 1987 and 1993, 11 ureteroceles in 10 children were treated by endoscopic incision: 7 intravesical ureteroceles (4 single system and 3 duplex system) and 4 duplex-system ectopic ureteroceles. The procedure consists of a tiny transversal incision at the lower and median aspects of the ureterocele.

RESULTS

The dilation of the upper urinary tract disappeared or decreased in all cases of intravesical ureteroceles and in half the cases of ectopic ureteroceles. Endoscopic incision of the ureterocele led to a vesicoureteral reflux in the associated ureter in 6 cases: 54.5% (43% of the intravesical ureteroceles, 75% of the ectopic ureteroceles). Following endoscopic treatment, no further surgery was required in 5 of the 7 cases with intravesical ureteroceles (71.5%), while every case of ectopic ureterocele needed a further operation (lower tract surgery in 3 cases, upper tract surgery in 1 case).

CONCLUSIONS

Endoscopic incision of ureteroceles is a simple and quick procedure which allows obstruction to be removed and the dilation of the upper urinary tract and its corresponding kidney function to be improved, particularly in the neonate. The endoscopic management of ureteroceles may in itself suffice, without necessity of further surgery. These favorable results can more readily be seen in cases of intravesical ureterocele than in those of ectopic ureterocele.

Oligodendrocytes express different isoforms of beta-amyloid precursor protein in chemically defined cell culture conditions: in situ hybridization and immunocytochemical detection

The expression of beta-amyloid precursor protein (betaAPP) by astrocytes is well documented; however, data concerning oligodendrocytes remain controversial. The main goal of the present study was to determine whether or not oligodendrocytes in culture constitutively express the different betaAPP isoforms. Oligodendrocytes were cultured in a chemically defined medium that avoids putative effects of unknown serum factors on oligodendrocyte development. We have employed immunocytochemistry and in situ hybridization with antibodies and synthetic oligonucleotides recognizing, respectively, specific protein epitopes and mRNA transcripts of rat betaAPP isoforms. Oligodendrocytes, in both mixed primary cultures in the presence of serum or in secondary cultures in defined medium, were clearly labeled by antibodies directed to different betaAPP sequences. Antibodies against the serine protease inhibitor domain of betaAPP, also strongly labelled oligodendrocytes. Immunohistochemistry and in situ hybridization were combined to determine precisely the expression of different isoforms of betaAPP. In situ hybridization revealed the presence in oligodendrocytes of mRNA transcripts coding not only for betaAPP695 but also for betaAPP770 and betaAPP751. This indicates that betaAPP immunoreactivity found in oligodendrocytes corresponds to constitutive expression of betaAPP. Oligodendrocyte cultured in chemically defined medium are able to express not only betaAPP695 but also betaAPP770, betaAPP751 isoforms containing the Kunitz protease inhibitor domain. Although the role of betaAPP in the pathological processes of Alzheimer's disease (AD) remains unknown, possible disturbances of betaAPP processing and/or synthesis in oligodendrocytes may account for some myelin disorders observed in AD and other senile dementias.

GAX 65: new injectable cross-linked collagen for the endoscopic treatment of vesicoureteral reflux--a double-blind study evaluating its efficiency in children

PURPOSE

In the experimental model glutaraldehyde cross-linked collagen GAX 65 with a collagen concentration of 65 mg./ml. has proved to have more persistent implant volume and, therefore, a better antireflux effect than GAX 35, which is injected more commonly. The aim of this study was to evaluate the potential clinical application of GAX 65.

MATERIALS AND METHODS

Ten boys and 8 girls an average of 4.6 years old presented with unilateral or bilateral primary reflux and were randomly divided into 2 groups. All refluxing ureters received 1 endoscopic subureteral injection of an average of approximately 2.9 ml. collagen. In group 1, 16 refluxing ureters were treated with GAX 65 and in group 2, 12 were treated with GAX 35. In all patients voiding cystourethrography was performed immediately after injection and 3 months postoperatively, and ultrasound was done on day 1, and at 1 and 3 months. Implant volume was calculated at the day of injection and at 3 months. The distribution of reflux grades was comparable in the 2 groups.

RESULTS

Both materials had excellent injection properties. Immediately after injection all ureters were reflux-free. Of the 16 ureters treated with GAX 65 14 (87.5%) were reflux-free at the 3-month followup. Three months postoperatively ultrasound revealed an average implant volume increase of one-third. However, of the 12 ureters treated with GAX 35 reflux had resolved in 59.3% and the average implant volume had decreased by half 3 months after injection.

CONCLUSIONS

Three months after endoscopic subureteral injection of GAX 65 vesicoureteral reflux was absent in 87.5% of patients. Therefore, GAX 65 has greater potential for treating reflux in the short term than GAX 35. To define the final efficacy of GAX 65 for treating vesicoureteral reflux, long-term evaluation of this series is necessary. In addition, further studies are mandatory to prove the long-term advantage of this new injectable substance.

Color Doppler ultrasound for evaluation of collagen implants after endoscopic injection treatment of refluxing ureters in children

To determine whether color Doppler ultrasonography (CDUS) would add to the understanding of the bladder wall after endoscopic subureteral collagen injection (SCIN), 25 patients were studied with CDUS. The kidney length and echogenicity, the volume of the collagen, the mean length of the urinary jet, the longitudinal and transverse angles, and the distance between the origin of the jet and the midline of the bladder were measured 1 day, 1 month, and 3 months after SCIN and compared to the results of micturating cystourethrograms (MCUs) performed 3 months after SCIN. The collagen was hyperechogenic compared to the bladder wall at the time of injection, and was isoechogenic 1 and 3 months after SCIN. CDUS showed the relationship between the injected collagen and the position of the ureteral orifice. The measurements of jet length, angle, and distance of the ureteral orifice from the midline did not correlate with vesicoureteral reflux assessed by MCU. Although CDUS may demonstrate the location, the size of the injected collagen implant, and its relationship to the ureteral orifice, it is as yet unable to predict vesicoureteral reflux after SCIN.

Distinct processing of endogenous and overexpressed recombinant presenilin 1

The presenilin 1 (PS1) gene has been identified by positional cloning. More than 30 mutations were detected in this gene which cosegregate with Alzheimer's disease (AD). Understanding their role in disease pathogenesis requires a characterization of the PS1 protein. We have generated a set of antibodies against the three major hydrophilic domains of the deduced amino acid sequence. Analyzing cultured cells and brain samples, we identified the endogenous PS1 polypeptide as well as amino- and carboxy-terminal fragments. These metabolites were much more abundant than the full-length molecule, indicating substantial processing. Overexpression of human PS1 markedly increased the full-length polypeptide but hardly altered the amount of the metabolites. Instead, additional proteolytic fragments appeared suggesting a different metabolism of the excess PS1, which may impede studies in transfected cells. Our results indicate a tight regulation of the endogenous PS1 metabolites. PS1 and its fragments are shown to be integral membrane proteins of the endoplasmic reticulum. The mechanisms regulating the generation of the metabolites, their potential function, and role in AD remain to be studied.

Combined Fmoc-Alloc strategy for a general SPPS of phosphoserine peptides; preparation of phosphorylation-dependent tau antisera

A block method for the solid phase synthesis (SPPS) of serine phosphopeptides has been developed using a combination of Fmoc and Alloc strategies. Alloc-Ser[PO(OCH2CH CH2)2] OH2, prepared in a one pot procedure from Alloc-Ser-OH, was introduced at the N-terminus of a sequence prepared by standard Fmoc-SPPS. Global cleavage of the allyl ester based protecting groups, followed by coupling of a tripeptide fragment, led to the tau phosphopeptide, 1. Using tau phosphopeptides a series of phosphorylation state-dependent antisera to human tau protein have been raised. These antisera are valuable tools for studying the tau protein which is found in an abnormal, hyperphosphorylated form in Alzheimer's disease brain.

Augmentation cystoplasty using pedicled and de-epithelialized gastric patches in the mini-pig model

PURPOSE

The most common methods of bladder augmentation are gastrocystoplasty and enterocystoplasty. Gastrocystoplasty is advantageous due to minimal mucous secretion and a well developed muscular wall as well as good urodynamic properties of the patch. However, the permanent contact of urine with the gastric mucosa is not free of complications. We report the urodynamic, macroscopic and histological outcomes of a pedicled de-epithelialized gastric patch incorporated in the bladder. We compared the results to those of our previous study, which sought to analyze these techniques of patch coverage using sigmoid patches.

MATERIALS AND METHODS

We performed 20 augmentation cystoplasties in the mini-pig model using a pedicled de-epithelialized gastric patch and 5 techniques of patch coverage.

RESULTS

Three months after surgery all bladders had an increase in volume except those in which the auto-augmentation technique was used. However, all gastric patches were smaller compared to preoperative size. Many had irregular fibrosed inner surfaces and histological evaluation revealed a fibrosed newly formed submucosal layer with a complete urothelial coverage in every patch. No gastric mucosal remnant was found.

CONCLUSIONS

De-epithelialized gastrocystoplasty is an attractive procedure that can increase bladder capacity as well as provide a complete urothelial lining without mucosal remnants. However, the success of this procedure seems to be limited by increased morbidity and fibrotic changes, and decreased surface of the patch.

Peripheral axotomy induces increased expression of neurotensin in large neurons in rat lumbar dorsal root ganglia

In normal rat lumbar 4 and 5 dorsal root ganglia (DRGs) a few large neurons expressed neurotensin-like immunoreactivity (LI). Twenty hours after crushing the lumbar 4 and 5 dorsal roots or the sciatic nerve, accumulations of neurotensin-LI were seen in many nerve fibers on the ganglionic side of both crushes, indicating a significant centrifugal transport of neurotensin under normal circumstances. A distinct increase in expression of neurotensin (peptide and mRNA) was observed in many large neuron profiles in the ipsilateral lumbar 4 and 5 DRGs two days after unilateral sciatic nerve transection. Two weeks after axotomy the number of neurotensin-positive neuron profiles was reduced and had almost reached normal levels. In the superficial dorsal horn of the lesion side the number of neurotensin immunoreactive fibers in laminae I-II was markedly reduced 7 days after peripheral axotomy. There was no detectable increase in neurotensin-L1 in laminae III-IV of spinal dorsal horn, in the dorsal column nuclei or in the peripheral neuroma (2-28 days after axotomy), suggesting that the amounts of neurotensin transported centrifugally from DRG neurons after axotomy are low. Neurotensin-LI only sometimes colocalized with neuropeptide Y-LI, another peptide known to be upregulated in large DRG neurons. These two peptides may therefore partly be localized in different populations of large DRG neurons. The present results show that, in contrast to the nerve injury-induced general downregulation of neurotensin systems in the superficial dorsal horn and of neurotensin receptor mRNA expression in DRGs as shown in previous studies, axotomy causes upregulation of expression of neurotensin peptide in some large DRG neurons.

Bilateral anterior pubic osteotomy in bladder exstrophy closure

PURPOSE

We report our clinical experience with anterior pelvic osteotomy in 16 patients who underwent surgery for bladder exstrophy. The technique and its difficulties are discussed.

MATERIALS AND METHODS

Anterior pelvic osteotomy of the superior ramus of the public bone is a simple and efficient method to facilitate symphyseal approximation and abdominal wall closure without or with low tension on the suture lines in neonates who undergo surgery for bladder exstrophy. Older children in whom surgery has been delayed can also benefit from this method. Compared to other methods of osteotomy in exstrophy surgery it does not require additional incisions, nor does the patient need to be repositioned on the operating table. A successful operation does not depend on any particular orthopedic skills and it can easily be done by the pediatric urologist.

RESULTS

Immediate postoperative results regarding abdominal wall closure were excellent in all 16 patients. However, major postoperative complications developed in 2 patients. Despite antibiotic prophylaxis a severe soft tissue infection developed in 1 child, resulting in complete bladder dehiscence. In another patient an obturator nerve injury resulted in transient palsy, which resolved completely. While the first complication was not related to osteotomy, the second was osteotomy related.

CONCLUSIONS

Bilateral superior ramotomy of the pubic bones is a new alternative, easily performed technique to optimize bladder exstrophy surgery in children.

[Endoscopic treatment of vesicoureterorenal reflux in the child]

In the first part of this review reflux per se and its conventional surgical therapy are presented. Then the minimally invasive, endoscopic subureteral injection is discussed as an alternative treatment of reflux. Last, the advantages and disadvantages of the substances used are evaluated. In the second part our experience with endoscopic subureteral collagen injection is presented and the results are critically analysed.

Conformations of synthetic beta peptides in solid state and in aqueous solution: relation to toxicity in PC12 cells

The secondary structures of peptides beta 25-35 (the active toxic fragment) and beta 35-25 (reverse sequence and non-toxic fragment), as well as of the amidated beta (25-35)-NH2 peptide were investigated in aqueous solution and in the solid state by means of Fourier-transformed infrared spectroscopy and circular dichroism spectroscopy. The conformations of the beta 25-35 and beta 35-25 in solid state were identical and contained mostly beta-sheet structures. In solid state the amidated beta (25-35)-NH2 peptide also contained mostly beta-sheet structures. Freshly prepared aqueous solutions of the beta 25-32 (0.5 - 3.8 mM) contained a mixture of beta-sheet and random coil structures. Within 30-60 min incubation at 37 degrees C in water or in phosphate-buffered saline solution (PBS), beta 25-35 was almost fully converted to a beta-sheet structure. Decreasing the temperature from 37 degrees C to 20 degrees C decreased the rate of conversion from random coil to beta-sheet structures, 1-2 h being required for complete conversion. In contrast beta 35-25 in water or in PBS buffer had mostly a random coil structure and remained so for 6 days. The amidated beta(25-35)-NH2 peptide in water (2.7 mM) was also mostly random coil. However, when this peptide (2-2.7 mM) was dissolved in PBS (pH 7.4) or in 140 mM NaCl, a gel was formed and its conformation was mostly beta-sheet. Decreasing the concentration of beta (25-35)-NH2 peptide in 140 mM NaCl aqueous solution from 2 mM to 1 mM or below favored the conversion from beta-sheet structures to random coil structures. The beta 25-35 was toxic to PC12 cells while beta 35-25 was not. The amidated peptide beta (25-35)-NH2 was at least 500-fold less toxic than beta 25-35. Structural differences between these beta peptides in aqueous solutions may explain the difference in their respective toxicities.

Cardiac perforation after surgical repair of pectus excavatum

Five days after surgical repair of pectus excavatum, this 7-year-old boy had a right-sided Kirschner wire protruding beneath the skin. The wire was repositioned blindly. Severe congestive heart failure developed. Surgical exploration showed a pierced right atrium, a torn septal leaflet of the tricuspid valve and noncoronary aortic cusp, and a large traumatic ventricular septal defect. The outcome and the indications and possible complications of surgery are discussed.

Physical and histological behavior of a new injectable collagen (GAX 65) implanted into the submucosal space of the mini-pig bladder

The aim of our study was to analyze the physical and histological behavior of a second generation collagen (GAX 65*) in the mini-pig bladder, comparing it to the commonly used substance for injection (GAX 35*). GAX 65 is a glutaraldehyde cross-linked bovine collagen with a collagen concentration of 65 mg./ml. This much higher collagen concentration could be achieved due to sophisticated manufacturing technology. In 18 mini-pigs 2 to 4, 1 ml. deposits of GAX 65 and 35, respectively, were implanted into the submucosal space of the surgically opened bladder. The animals were sacrificed at months 1, 2, 4 and 6. The elevation (height equals protrusion of the implant into the bladder) and volume of the implants were measured and calculated immediately after injection and at necropsy. Histology was performed. The GAX 65 implants had a lesser decrease of elevation and volume during the 6-month observation period. Histology showed that the invasion of endogenous fibroblasts into the GAX 35 and 65 implants, and the formation of porcine collagen types I and III were almost identical. Clinically GAX 65 has better elevation properties than GAX 35 although statistical analysis did not show any significant difference (p = 0.07 to 0.25). However, preservation of the volume of the GAX 65 implant was significantly superior (p < or = 0.05) compared to that of GAX 35. Therefore, GAX 65 will most probably prove to be an excellent substance for the endoscopic treatment of vesicoureteral reflux and incontinence in children.

Endoscopic subureteral collagen injection for the treatment of vesicoureteral reflux in infants and children

Between June 1988 and September 1994, 100 girls and 32 boys 2 months to 15.5 years old (average 4.9 years) with 204 refluxing ureteral units were treated by endoscopic subureteral collagen injection. The collagen injected was of bovine origin and cross-linked with glutaraldehyde (Zyplast*). Followup ranged from 3 to 75 months (mean 33). Reflux was absent in 62.7% of cases 3 months after 1 endoscopic subureteral injection. Improvement to reflux grades I and II, generally not requiring further treatment, occurred in a further 15.2% of cases. A total of 66 ureters was injected twice. The overall cure rate after 1 or 2 injections was 79.4% 3 months after injection. There was no correlation between the risk of recurrent reflux and initial degree of reflux. Late recurrence of reflux following a reflux-free period occurred in 11.3% of the 204 units during the observation period, which varied from 3 months to 6 1/4 years. Reflux was absent after 1 or 2 injections, including late recurrence, in 70.6% of cases and in an additional 13.2% recurrent reflux was grade I or II, not necessitating any further treatment. Considering these results, subureteral collagen injection remains an adequate method of treatment for vesicoureteral reflux in children.