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Biomedical subjects

A Le Duc

Publications and source records attributed to A Le Duc.

At least 37 records · Page 2Linked to original sources
PubMed1999

BTA stat and BTA TRAK: A comparative evaluation of urine testing for the diagnosis of transitional cell carcinoma of the bladder.

OBJECTIVE: We compared the BTA (bladder tumor antigen) stat test with the BTA TRAK assay in patients highly suspicious of bladder cancer. METHODS: The BTA stat and the BTA TRAK tests are two immunoassays that detect human complement factor H related protein in urine, employing the same antibody pair. The BTA stat is a qualitative test which can be performed in a consultation setting. The BTA TRAK is a quantitative test that is performed in the laboratory. Consecutive patients highly suspicious of bladder cancer were included in this prospective blinded trial to assess the clinical performances of the two methods. RESULTS: A total of 81 patients were tested using BTA stat and BTA TRAK before cystoscopy. A tumor was identified in 49 patients. BTA TRAK (38/49 true-positive cases) was more sensitive than BTA stat (32/49) in detecting bladder cancer (p < 0.05). When considering the subgroups of bladder cancer by stage and grade, the difference remained significant for low-grade and low-stage tumors. There was no significant difference between BTA TRAK and BTA stat as regards specificity (20/32 and 23/32 true-negative cases, respectively; p = 0.2). CONCLUSION: BTA TRAK with a cutoff of 14 U/ml had a significantly higher sensitivity than BTA stat in the detection of low-grade and low-stage bladder cancer.

Aged↗
PubMed1999

Holmium laser resection of the prostate.

OBJECTIVE: This review of holmium laser resection of the prostate (HoLRP) summarises the evolution, points of technique, results of clinical trials and ongoing research concerning this procedure. METHODS: Over 3 years of experience with holmium resection/enucleation in two institutions is reviewed. Several open studies and 2 randomised trials are presented and the results discussed. Current work with holmium enucleation of the prostate (HoLEP) in combination with intracavitary morcellation is also reported. RESULTS: HoLRP results in fewer blood transfusions, less nursing contact time, less requirement for bladder irrigation, and a shorter catheter time and hospital stay than for patients treated with standard electrocautery resection of the prostate (TURP). Preliminary results suggest equivalent symptomatic relief, and relief of bladder outflow obstruction between the two procedures. CONCLUSIONS: Holmium prostatectomy continues to evolve. Preliminary experience suggests that it may be a viable alternative to TURP and appears to have some significant advantages. Newer techniques for tissue retrieval may significantly decrease the operating time.

Holmium↗
PubMed1999

Thermal radiofrequency induced porcine ureteral stricture: a convenient endourologic model.

PURPOSE: To establish a reliable model of iatrogenic ureteral stricture mimicking the human clinical situation in order to experiment with new site-specific endourologic treatment concepts. MATERIALS AND METHODS: After cystoscopic insertion of a 7F right ureteral catheter, we induced external thermal radiofrequency injury to the right upper third ureter at low power setting (10 W) using an open surgical approach in 13 pigs. Three pigs considered as controls underwent the same procedure without application of electrocautery. All 16 animals were initially assessed at 8 days; 3 study animals and the 3 controls were followed for 6 weeks. RESULTS: No control animals had strictures. Significant upper third ureteral strictures with marked hydronephrosis where achieved in all study animals after a mean interval of 9 days, as evidenced by ultrasound examination and retrograde ureteropyelography. Endoscopic retrograde access to these strictures was always possible (mean length 1.4 cm.). Histologic examination displayed severe disorganization of the muscular layer by dense fibrosis composed of collagen bundles with few scattered fibroblasts. No spontaneous improvement of the stricture was observed in the 3 animals reassessed at 6 weeks. CONCLUSIONS: Externally applied radiofrequency energy to porcine ureter provides a reproducible model of fibrous stricture resembling its clinical counterparts.

Animals↗
PubMed1999

A 3 trocar technique for transperitoneal laparoscopic nephrectomy.

PURPOSE: Additional trocars and retractor instruments may enhance the risk of iatrogenic injuries during laparoscopic nephrectomy. We describe a modified technique of laparoscopic nephrectomy requiring only 3 ports of entry and no extra instruments instead of the 5 ports, 2 of which are used for retractors, usually required. MATERIALS AND METHODS: With the patient in full flank position a 10 mm. trocar is inserted between the umbilicus and subcostal margin, a 5 mm. trocar is placed subcostal in the midclavicular line and a 12 mm. trocar is inserted over the iliac crest in the anterior axillary line. The first step is incision of the line of Toldt and medial reflection of the colon. During the second step of vascular controls the posterosuperior attachments of the kidney are left untouched, keeping the renal vessels stretched, with no need for an extra instrument. The third step consists of severing the remaining posterior and superior attachments of the kidney followed by specimen retrieval. A total of 14 consecutive patients underwent laparoscopic nephrectomy with this technique. RESULTS: All 14 procedures were completed without an additional port. There were no intraoperative or postoperative complications, except 1 abdominal wall hematoma. Mean operating time was 120 minutes (range 70 to 230) and mean hospital stay was 5 days (range 3 to 7). CONCLUSIONS: Transperitoneal laparoscopic nephrectomy with laparoscopic access limited to 3 trocars is a reliable and safe technique.

Adolescent↗
PubMed1999

Ureteral gene transfer to porcine induced strictures using endourologic delivery of an adenoviral vector.

PURPOSE: Direct gene transfer to the ureter is an attractive approach to prevent restenosis after endourologic management of ureteral strictures. We therefore assessed the rationale for adenovirus-mediated gene transfer in the ureter in vitro and in vivo using a porcine model. MATERIALS AND METHODS: Primary cultures of porcine ureteral epithelial and stromal cells were infected with an adenoviral solution carrying a nucleus-targeted beta-Galactosidase (beta-Gal) reporter gene (6.5 10(8) pfu/ml.). In addition, in order to mimic the human clinical situation, we have devised a model of thermally-induced stricture in porcine ureter which produced tight fibrotic stenosis within 8 days. Using a purposely designed channelled balloon catheter prototype, these strictures were endoscopically dilated and then instilled with the same beta-Gal adenoviral construction. RESULTS: Application of recombinant adenovirus harboring a nucleus-targeted beta-Gal reporter gene to cultured porcine urothelial and stromal cells resulted in high transduction efficiency of up to 99% and 84% respectively. Seven days after infection, X-Gal staining of the strictured ureters demonstrated transfection up to 2 mm. depth within the fibrosis, confirmed by polymerase chain reaction (PCR) analysis. Adjacent and distal spread of the virus was excluded by histochemistry (X-Gal staining) and PCR. CONCLUSION: This data represents the first report of adenovirus-mediated gene transfer to the ureter. It remained site specific by endourologic retrograde clinically applicable techniques.

Adenoviridae↗
PubMed1998

Assessment of microsatellite instability in urine in the detection of transitional-cell carcinoma of the bladder.

Loss of heterozygosity (LOH) and alterations in microsatellite DNA markers have been reported in bladder-cancer tumors. We have studied, in a blinded fashion, using PCR-based microsatellite analysis, genetic alterations of cells exfoliated in urine of 59 Caucasian patients and control patients; 31 with initially confirmed bladder transitional-cell carcinoma (TCC), 17 with signs and symptoms suggestive of bladder cancer, 6 control patients who underwent renal transplantation, and 5 control patients with urolithiasis. Microsatellite analysis of cells exfoliated in the urine allowed the diagnosis of 83% (10/12) of patients with bladder TCC recurrence confirmed by cystoscopy, while 100% of patients followed up for transitional-cell carcinoma of the bladder for up to 12 months without evidence of tumor recurrence upon routine cystoscopy showed no microsatellite alterations. None of the patients without neoplasia (negative controls) had any microsatellite alterations, whereas all patients who underwent renal transplantation had additional new alleles corresponding to contamination with donor's renal and urothelial cells (positive controls). No control patients had any evidence of transitional-cell carcinoma by cystoscopy. Our results provide objective evidence that non-invasive molecular detection of bladder TCC by microsatellite analysis is reproducible with a sensitivity of 83% and a specificity of 100% in Caucasian patients. This non-invasive procedure represents a potential clinical tool for the detection and the screening of bladder TCC.

Adult↗
PubMed1998

The role of laser-induced autofluorescence spectroscopy in bladder tumor detection. Dependence on the excitation wavelength.

We assessed the ability of laser-induced autofluorescence spectroscopy to distinguish neoplastic urothelial bladder lesions from normal or nonspecific inflammatory mucosa. Three different pulsed laser excitation wavelengths were used successively: 308 nm (xenium chloride excimer laser), 337 nm (nitrogen laser) and 480 nm (coumarin dye laser). The excitation light was delivered by a specially devised multifiber catheter connected to a 1-mm core diameter silica monofiber introduced through the working channel of a standard cystoscope with saline irrigation. The captured fluorescence light was focused onto an optical multichannel analyzer detection system. Performance of this device was evaluated in 25 patients after obtaining consent and immediately before transurethral resection of a bladder tumor. Spectroscopic results were compared with histological findings. At 337- and 480-nm excitation wavelengths, the overall fluorescence intensity of bladder tumors was clearly decreased compared to normal urothelial mucosa regardless of tumor stage and grade. At the 308-nm excitation wavelength, the shape of the tumor spectra, including carcinoma in situ, was markedly different from that of normal or nonspecific inflammatory mucosa. No absolute intensity determinations were required in this situation, since a definite diagnosis could be established based on the fluorescence intensity ratio at 360 and 440 nm. This spectroscopic study could be particularly useful in designing a simplified autofluorescence imaging device for detection of occult urothelial neoplasms.

Aged↗
PubMed1998

Total ureteral replacement by subcutaneous pyelovesical bypass in ureteral necrosis after renal transplantation.

OBJECTIVES: Ureteral necrosis is a rare complication of renal transplantation, and is seldom cured by endoscopic management alone. To avoid the potential hazard to the graft created by an open ureteral reconstruction in cases of renal transplant ureteral necrosis, we have appiled a new minimally invasive technique of total ureteral replacement, initially described for the palliative treatment of ureteral obstructions. The subcutaneous bypass technique is based on the use of a silicone-PTFE-bonded tube tunnelled underneath the skin. METHODS: Total ureteral replacement by subcutaneous pyelovesical bypass was performed in three renal transplant patients (two men and one woman; mean age 41 years, (range 23-58) years with ureteral necrosis after failure of primary endoscopic treatment. The ureteral lesion was distal necrosis in two patients, and a total necrosis in the other. Under general anaesthesia and fluoroscopic guidance, a percutaneous tract was created and progressively dilated. The ureteral prosthesis was introduced into the pyelocaliceal cavities through a 30 F Amplatz sheet, then subcutaneously tracked down to the suprapubic area, and introduced into the bladder via a short incision. RESULTS: There was no operative or postoperative morbidity. There was no obstruction, dislodgement or encrustation of the prosthesis. There were no bladder-related symptoms, or clinical reflux, and no abdominal wall complications. An asymptomatic episode of lower urinary tract infection (Staphylococcus epidermidis) was observed in the female patient. All the grafts were functioning with fine pyelocaliceal cavities, with a mean follow-up of 32 months (13-69 months). CONCLUSION: Total ureteral replacement by subcutaneous pyelovesical bypass is a simple and safe technique of ureteral reconstruction in renal transplantation. Late encrustation of the prosthesis may occur, and the prosthesis may need to be changed in such cases. Subcutaneous pyelovesical bypass can be regarded as an alternative to an open procedure to treat ureteral necrosis after renal transplantation.

Adult↗
PubMed1998

Artificial ureteral replacement for ureteral necrosis after renal transplantation: report of 3 cases.

PURPOSE: We applied a new minimally invasive technique of artificial ureteral replacement for renal transplant ureteral necrosis. MATERIALS AND METHODS: Artificial ureteral replacement was performed in 3 renal transplant recipients with ureteral necrosis (complete in 1 and distal in 2) after failure of primary endoscopic treatment. Under fluoroscopic guidance a percutaneous tract is created and progressively dilated. The ureteral silicone polytetrafluoroethylene bonded tube is introduced into the pyelocaliceal renal graft cavities, tracked subcutaneously down to the suprapubic area and introduced into the bladder via a short incision. RESULTS: There were no immediate postoperative complications except for transient postoperative acute prostatitis in 1 patient. No secondary complications were observed with a mean followup of 2.5 years. All grafts have good late function and all tubes are patent with no evidence of encrustation or obstruction. The tubes are well tolerated underneath the skin. Reflux was present in all 3 cases with no clinical manifestation. An asymptomatic episode of lower urinary tract infection was observed in the female patient. CONCLUSIONS: In select cases of ureteral necrosis after renal transplantation artificial ureteral replacement by subcutaneous pyelovesical bypass offers a possible alternative to open ureteral reconstruction.

Adult↗
PubMed1998

Urethral graciloplasty for treatment of female intrinsic sphincter deficiency: rationale for the transvaginal approach: an anatomical study.

PURPOSE: To compare the retropubic and transvaginal approaches in terms of the length of gracilis muscle available for female urethral graciloplasty. MATERIALS AND METHODS: Two groups of female cadavers were submitted to bilateral gracilis muscle dissection, followed by urethral graciloplasty using either the standard retropubic approach or the transvaginal approach. The two groups were studied in terms of various muscle characteristics, in particular the length of muscle that could effectively be wrapped around the bladder neck. RESULTS: Because muscle transfer to the perineum was more direct, the transvaginal approach provided a greater functional length of gracilis for effective periurethral wrapping than the retropubic approach (mean: 8.4 cm. versus 5.2 cm., p = 0.0022). CONCLUSION: The transvaginal approach allows a more "proximal" graciloplasty and should therefore be evaluated clinically to provide circumferential bladder neck support without tension.

Aged↗
PubMed1998

Predisposing gene for early-onset prostate cancer, localized on chromosome 1q42.2-43.

There is genetic predisposition associated with >=10% of all cancer of the prostate (CaP). By means of a genomewide search on a selection of 47 French and German families, parametric and nonparametric linkage (NPL) analysis allowed identification of a locus, on chromosome 1q42.2-43, carrying a putative predisposing gene for CaP (PCaP). The primary localization was confirmed with several markers, by use of three different genetic models. We obtained a maximum two-point LOD score of 2.7 with marker D1S2785. Multipoint parametric and NPL analysis yielded maximum HLOD and NPL scores of 2.2 and 3.1, respectively, with an associated P value of . 001. Homogeneity analysis with multipoint LOD scores gave an estimate of the proportion of families with linkage to this locus of 50%, with a likelihood ratio of 157/1 in favor of heterogeneity. Furthermore, the 9/47 families with early-onset CaP at age <60 years gave multipoint LOD and NPL scores of 3.31 and 3.32, respectively, with P = .001.

Age of Onset↗
PubMed1998

Encrusted cystitis and pyelitis.

PURPOSE: Encrusted cystitis and pyelitis are chronic inflammations of the bladder and collecting system associated with mucosal encrustations induced by urea splitting bacteria. We review these infectious diseases. MATERIALS AND METHODS: A literature search was performed of the MEDLINE database from 1985 to 1997. Additional articles published before 1985 were also selectively included. RESULTS: Most of the articles were case reports or short series. During the last 10 years increasing numbers of cases have been diagnosed, especially in immunodepressed patients, and particularly in renal transplant recipients. Many bacteria have been demonstrated in this infection but Corynebacterium group D2 is currently the most frequent. The development of encrusted cystitis or pyelitis requires the presence of specific bacteria with an alkaline urine, a preexisting urological procedure and a clinical context predisposing to infection. Clinical diagnosis can be difficult but the presence of alkaline urine containing abundant calcified mucopurulent debris is highly suggestive. Demonstration of the bacteria requires prolonged cultures in enriched media. Treatment is based on adapted antibiotic therapy, acidification of urine and excision of plaques of calcified encrustation. The consequences of treatment failure are serious and can result in graft nephrectomy in kidney transplant recipients. CONCLUSIONS: Early clinical and bacterial diagnosis of encrusted cystitis and pyelitis could improve the prognosis of these infectious diseases.

Calcium↗
PubMed1997

[Indications and results of treatments of bladder tumors].

Bladder tumours have a variety of appearances, ranging from a purely mucosal, minimally invasive lesion to an invasive cancer with definite metastatic potential. Each type of tumour corresponds to a particular treatment which takes into account multiple factors, none of which, at the present time, is able to definitely predict the outcome of a tumour at the time of its discovery. Treatments by endoscopic resection and intravesical instillation are designed to control recurrences of superficial bladder tumours. Surgical resection of the bladder, radiotherapy and chemotherapy, either alone or combined with radiotherapy, are designed to cure the bladder cancer or delay its progression. While awaiting a therapeutic revolution, recent efforts have attempted to improve the quality of life of patients escaping from treatment.

Humans↗
PubMed1997

A comparative study of guidewire electrical resistance.

OBJECTIVE: To evaluate the electrical resistance to current conduction of different guidewires used routinely in endourology and thus determine the risk of short circuits between the active electrode and the guide. MATERIALS AND METHODS: Using a standard resistance meter, the electrical resistance of four different types of guidewires was measured. Pure stainless-steel, polytetrafluoroethylene (PTFE)-painted, PTFE-sheathed and hydrogel-sheathed guidewires were tested, both when new and after mechanical abrasion of the external layer to reproduce their condition after use. RESULTS: The pure stainless-steel guidewire had no resistance to electrical current. The electrical insulation of the PTFE-painted guidewires was poor and was eliminated by mechanical abrasion of the paint. New PTFE-sheathed and hydrogel-sheathed guidewires had a safe electrical resistance (> 10 K omega) but this insulation was easily eliminated by mechanical abrasion of the external layer. CONCLUSIONS: To minimize the risk of electrosurgical adverse effects during a guidewire-assisted endoscopic procedure, the operator should preferably use a new guidewire for each procedure, use sheathed guidewires and ensure that the guidewire is in good condition, or cover it with a ureteric catheter, before applying current.

Electric Conductivity↗
PubMed1997

An in vitro comparison of urease-induced encrustation of JJ stents in human urine.

OBJECTIVE: To report the results of a comparative study of in vitro encrustation of five different types of JJ stents in human urine. MATERIALS AND METHODS: Samples of five JJ stents (polyurethane, silicone, Percuflex, C-Flex and hydrogel-coated C-Flex) were immersed for 24 h at 37 degrees C in fresh human urine supplemented with urease, and the surface photographed and dried. The crystals formed on the stents were dissolved in hydrochloric acid and the calcium and magnesium concentrations determined. RESULTS: Large crystals were deposited on the surface of the hydrogel-coated C-Flex stent and significantly higher levels of calcium and magnesium salts were obtained after acidic dissolution. There were no differences in crystal deposition among the remaining stents. CONCLUSION: Hydrogel-coated stents have an higher risk of becoming encrusted in vitro than do uncoated stents made of the same substrate polymer or made of different materials. These results emphasize the need for the regular follow-up of patients with hydrophilic stents in place.

Crystallization↗
PubMed1997

New experimental model of ureteropelvic junction obstruction allowing easy access for percutaneous surgery.

To assess the usefulness of an experimental model of ureteropelvic junction (UPJ) obstruction designed to facilitate subsequent percutaneous surgery, a right UPJ obstruction was created in 10 pigs by an open retroperitoneal surgical approach. With the pig in the left lateral decubitus position, a 0.038-inch Terumo guidewire was inserted via a 1-cm longitudinal upper-third ureterotomy and advanced up and down so as to bridge the UPJ from the flank to the urogenital opening. A UPJ obstruction was then induced by securing two 2-0 chromic gut ties, separated by an interval of 1 cm, over the Terumo guidewire and a 6F ureteral catheter, which was removed immediately after this procedure. After closure of the ureterotomy, the kidney was anchored horizontally to the muscle wall, and the Terumo guidewire was coiled subcutaneously in the flank and fixed to the urogenital opening. Each pig developed marked hydronephrosis, diagnosed by ultrasonography, after a mean interval of 8.3 days. Retrograde ureteropyelography confirmed this pronounced dilation of the right collecting system above a tight UPJ stricture (mean length 1.17 cm). Subsequent percutaneous access to the UPJ over the Terumo guidewire in the lateral decubitus position was facilitated by the almost-horizontal plane of dilation (mean operating time 14 minutes). Pathologic examination of the UPJ revealed mild periureteral fibrosis, but the muscle layer and urothelium remained normal. We have developed a reliable and reproducible model of secondary UPJ obstruction especially designed for percutaneous surgery. This model should provide a better understanding of current endoscopic techniques such as endopyelotomy and could help to promote new treatment concepts such as percutaneous endoscopic pyeloplasty.

Anastomosis, Surgical↗
PubMed1997

Spontaneous rupture of orthotopic detubularized ileal bladder replacement: report of 5 cases.

PURPOSE: We defined the mechanisms responsible for rupture of orthotopic, detubularized ileal bladder replacement. MATERIALS AND METHODS: We reviewed retrospectively the records of 5 cases of ileal neobladder rupture treated at our center between 1985 and 1995. RESULTS: The interval to perforation varied from 3 to 60 months after surgery. The perforation site was typically the upper part of the right limb of the reservoir. We observed an acute episode of bladder over distension immediately before perforation in 2 cases and a chronic state of neobladder over distension in the 3 remaining cases. Bacterial infection was associated in 4 cases. Intraperitoneal adhesions were an associated mechanism for rupture in only 1 case. We found chronic ischemic changes weakening the bladder wall to be an additional factor for rupture in the 3 cases associated with chronic over distension. CONCLUSIONS: Acute or chronic over distension of the neobladder is the main factor for spontaneous rupture of orthotopic detubularized ileal bladder replacement. Chronic ischemic changes of the bladder wall, possibly facilitated by detubularization and the variability of the mesenteric circulation, are additional factors that lead to perforation.

Aged↗