The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Michael T. Walsh - One of the best experts on this subject based on the ideXlab platform.
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preventing Urethral trauma from inadvertent inflation of catheter balloon in the Urethra during catheterization evaluation of a novel safety syringe after correlating trauma with Urethral distension and catheter balloon pressure
The Journal of Urology, 2017Co-Authors: Rory O C Mooney, Conor V. Cunnane, Eoghan M. Cunnane, John A. Thornhill, Niall F. Davis, Michael T. WalshAbstract:Purpose: We investigated Urethral diametric strain and threshold maximum inflation pressure for rupture during inadvertent inflation of a catheter anchoring balloon in the Urethra. In addition, we evaluated a novel safety device to prevent trauma based on these parameters.Materials and Methods: Inflation of a Urethral catheter anchoring balloon was performed in the bulbar Urethra of 21 ex vivo porcine models using 16Fr catheters. Urethral trauma was assessed with retrograde urethrography. Urethral rupture was correlated with internal Urethral diametric strain and maximal Urethral pressure threshold values in kPa. Urethral catheters were then inflated in the bulbar Urethras of 7 fresh male cadavers using a standard syringe and a prototype syringe. The plunger of the standard syringe was depressed until opposing resistance pressure generated by the Urethra prevented further inflation of the anchoring balloon. The plunger of the prototype safety syringe was depressed until sterile water in the syringe decant...
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Preventing Urethral trauma from inadvertent inflation of catheter balloon in the Urethra during catheterization: Evaluation of a novel safety syringe after correlating trauma with Urethral distension and catheter balloon pressure
Journal of Urology, 2015Co-Authors: Niall F. Davis, Rory O C Mooney, Conor V. Cunnane, Eoghan M. Cunnane, John A. Thornhill, Michael T. WalshAbstract:Purpose We investigated Urethral diametric strain and threshold maximum inflation pressure for rupture during inadvertent inflation of a catheter anchoring balloon in the Urethra. In addition, we evaluated a novel safety device to prevent trauma based on these parameters. Materials and Methods Inflation of a Urethral catheter anchoring balloon was performed in the bulbar Urethra of 21 ex vivo porcine models using 16Fr catheters. Urethral trauma was assessed with retrograde urethrography. Urethral rupture was correlated with internal Urethral diametric strain and maximal Urethral pressure threshold values in kPa. Urethral catheters were then inflated in the bulbar Urethras of 7 fresh male cadavers using a standard syringe and a prototype syringe. The plunger of the standard syringe was depressed until opposing resistance pressure generated by the Urethra prevented further inflation of the anchoring balloon. The plunger of the prototype safety syringe was depressed until sterile water in the syringe decanted through an activated safety threshold pressure valve. Results Retrograde urethrography demonstrated that porcine Urethral rupture consistently occurred at an internal Urethral diametric strain greater than 40% and a maximum inflation pressure greater than 150 kPa. The mean ± SD maximum human Urethral threshold inflation pressure required to activate the safety prototype syringe pressure valve was 153 ± 3 kPa. In comparison, maximum inflation pressure was significantly greater using the standard syringe than the activated prototype syringe (mean 452 ± 188 kPa, p
Niall F. Davis - One of the best experts on this subject based on the ideXlab platform.
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preventing Urethral trauma from inadvertent inflation of catheter balloon in the Urethra during catheterization evaluation of a novel safety syringe after correlating trauma with Urethral distension and catheter balloon pressure
The Journal of Urology, 2017Co-Authors: Rory O C Mooney, Conor V. Cunnane, Eoghan M. Cunnane, John A. Thornhill, Niall F. Davis, Michael T. WalshAbstract:Purpose: We investigated Urethral diametric strain and threshold maximum inflation pressure for rupture during inadvertent inflation of a catheter anchoring balloon in the Urethra. In addition, we evaluated a novel safety device to prevent trauma based on these parameters.Materials and Methods: Inflation of a Urethral catheter anchoring balloon was performed in the bulbar Urethra of 21 ex vivo porcine models using 16Fr catheters. Urethral trauma was assessed with retrograde urethrography. Urethral rupture was correlated with internal Urethral diametric strain and maximal Urethral pressure threshold values in kPa. Urethral catheters were then inflated in the bulbar Urethras of 7 fresh male cadavers using a standard syringe and a prototype syringe. The plunger of the standard syringe was depressed until opposing resistance pressure generated by the Urethra prevented further inflation of the anchoring balloon. The plunger of the prototype safety syringe was depressed until sterile water in the syringe decant...
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Preventing Urethral trauma from inadvertent inflation of catheter balloon in the Urethra during catheterization: Evaluation of a novel safety syringe after correlating trauma with Urethral distension and catheter balloon pressure
Journal of Urology, 2015Co-Authors: Niall F. Davis, Rory O C Mooney, Conor V. Cunnane, Eoghan M. Cunnane, John A. Thornhill, Michael T. WalshAbstract:Purpose We investigated Urethral diametric strain and threshold maximum inflation pressure for rupture during inadvertent inflation of a catheter anchoring balloon in the Urethra. In addition, we evaluated a novel safety device to prevent trauma based on these parameters. Materials and Methods Inflation of a Urethral catheter anchoring balloon was performed in the bulbar Urethra of 21 ex vivo porcine models using 16Fr catheters. Urethral trauma was assessed with retrograde urethrography. Urethral rupture was correlated with internal Urethral diametric strain and maximal Urethral pressure threshold values in kPa. Urethral catheters were then inflated in the bulbar Urethras of 7 fresh male cadavers using a standard syringe and a prototype syringe. The plunger of the standard syringe was depressed until opposing resistance pressure generated by the Urethra prevented further inflation of the anchoring balloon. The plunger of the prototype safety syringe was depressed until sterile water in the syringe decanted through an activated safety threshold pressure valve. Results Retrograde urethrography demonstrated that porcine Urethral rupture consistently occurred at an internal Urethral diametric strain greater than 40% and a maximum inflation pressure greater than 150 kPa. The mean ± SD maximum human Urethral threshold inflation pressure required to activate the safety prototype syringe pressure valve was 153 ± 3 kPa. In comparison, maximum inflation pressure was significantly greater using the standard syringe than the activated prototype syringe (mean 452 ± 188 kPa, p
Anthony Atala - One of the best experts on this subject based on the ideXlab platform.
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3d bioprinting of Urethra with pcl plcl blend and dual autologous cells in fibrin hydrogel an in vitro evaluation of biomimetic mechanical property and cell growth environment
Acta Biomaterialia, 2017Co-Authors: Anthony Atala, Kaile Zhang, Qiang Fu, Xiangxian Chen, Prafulla Chandra, Xiumei Mo, Lujie Song, Weixin ZhaoAbstract:Abstract Objective Urethral stricture is a common condition seen after Urethral injury. The currently available treatments are inadequate and there is a scarcity of substitute materials used for treatment of Urethral stricture. The traditional tissue engineering of Urethra involves scaffold design, fabrication and processing of multiple cell types. Methods In this study, we have used 3D bioprinting technology to fabricate cell-laden Urethra in vitro with different polymer types and structural characteristics. We hypothesized that use of PCL and PLCL polymers with a spiral scaffold design could mimic the structure and mechanical properties of natural Urethra of rabbits, and cell-laden fibrin hydrogel could give a better microenvironment for cell growth. With using an integrated bioprinting system, tubular scaffold was formed with the biomaterials; meanwhile, urothelial cells (UCs) and smooth muscle cells (SMCs) were delivered evenly into inner and outer layers of the scaffold separately within the cell-laden hydrogel. Results The PCL/PLCL (50:50) spiral scaffold demonstrated mechanical properties equivalent to the native Urethra in rabbit. Evaluation of the cell bioactivity in the bioprinted Urethra revealed that UCs and SMCs maintained more than 80% viability even at 7 days after printing. Both cell types also showed active proliferation and maintained the specific biomarkers in the cell-laden hydrogel. Conclusion These results provided a foundation for further studies in 3D bioprinting of Urethral constructs that mimic the natural Urethral tissue in mechanical properties and cell bioactivity, as well a possibility of using the bioprinted construct for in vivo study of Urethral implantation in animal model. Significance of Statements The 3D bioprinting is a new technique to replace traditional tissue engineering. The present study is the first demonstration that it is feasible to create a Urethral construct. Two kinds of biomaterials were used and achieved mechanical properties equivalent to that of native rabbit Urethra. Bladder epithelial cells and smooth muscle cells were loaded in hydrogel and maintained sufficient viability and proliferation in the hydrogel. The highly porous scaffold could mimic a natural Urethral base-membrane, and facilitate contacts between the printed epithelial cells and smooth muscle cells on both sides of the scaffold. These results provided a strong foundation for future studies on 3D bioprinted Urethra.
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penile Urethra replacement with autologous cell seeded tubularized collagen matrices
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Roger E De Filippo, Benjamin S Kornitzer, Anthony AtalaAbstract:Acellular collagen matrices have been used as an onlay material for Urethral reconstruction. However, cell-seeded matrices have been recommended for tubularized Urethral repairs. In this study we investigated whether long segmental penile Urethral replacement using autologous cell-seeded tubularized collagen-based matrix is feasible. Autologous bladder epithelial and smooth muscle cells from nine male rabbits were grown and seeded onto preconfigured tubular matrices constructed from decellularized bladder matrices obtained from lamina propria. The entire anterior penile Urethra was resected in 15 rabbits. Urethroplasties were performed with tubularized matrices seeded with cells in nine animals, and with matrices without cells in six. Serial urethrograms were performed at 1, 3 and 6 months. Retrieved Urethral tissues were analysed using histo- and immunohistochemistry, western blot analyses and organ bath studies. The urethrograms showed that animals implanted with cell-seeded matrices maintained a wide Urethral calibre without strictures. In contrast, the Urethras with unseeded scaffolds collapsed and developed strictures. Histologically, a transitional cell layer surrounded by muscle was observed in the cell-seeded constructs. The epithelial and smooth muscle phenotypes were confirmed with AE1/AE3 and α-actin antibodies. Organ bath studies of the neoUrethras confirmed both physiological contractility and the presence of neurotransmitters. Tubularized collagen matrices seeded with autologous cells can be used successfully for long segmental penile Urethra replacement, while implantation of tubularized collagen matrices without cells leads to poor tissue development and stricture formation. The cell-seeded collagen matrices are able to form new tissue, which is histologically similar to native Urethra. Copyright © 2012 John Wiley & Sons, Ltd.
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tissue engineered autologous Urethras for patients who need reconstruction an observational study
The Lancet, 2011Co-Authors: Diego R Esquiliano, Atlantida M Rayarivera, Esther Lopezbayghen, Shay Soker, Anthony AtalaAbstract:Summary Background Complex Urethral problems can occur as a result of injury, disease, or congenital defects and treatment options are often limited. Urethras, similar to other long tubularised tissues, can stricture after reconstruction. We aimed to assess the effectiveness of tissue-engineered Urethras using patients' own cells in patients who needed Urethral reconstruction. Methods Five boys who had Urethral defects were included in the study. A tissue biopsy was taken from each patient, and the muscle and epithelial cells were expanded and seeded onto tubularised polyglycolic acid:poly(lactide-co-glycolide acid) scaffolds. Patients then underwent Urethral reconstruction with the tissue-engineered tubularised Urethras. We took patient history, asked patients to complete questionnaires from the International Continence Society (ICS), and did urine analyses, cystourethroscopy, cystourethrography, and flow measurements at 3, 6, 12, 24, 36, 48, 60, and 72 months after surgery. We did serial endoscopic cup biopsies at 3, 12, and 36 months, each time in a different area of the engineered Urethras. Findings Patients had surgery between March 19, 2004, and July 20, 2007. Follow-up was completed by July 31, 2010. Median age was 11 years (range 10–14) at time of surgery and median follow-up was 71 months (range 36–76 months). AE1/AE3, α actin, desmin, and myosin antibodies confirmed the presence of cells of epithelial and muscle lineages on all cultures. The median end maximum urinary flow rate was 27·1 mL/s (range 16–28), and serial radiographic and endoscopic studies showed the maintenance of wide Urethral calibres without strictures. Urethral biopsies showed that the engineered grafts had developed a normal appearing architecture by 3 months after implantation. Interpretation Tubularised Urethras can be engineered and remain functional in a clinical setting for up to 6 years. These engineered Urethras can be used in patients who need complex Urethral reconstruction. Funding National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.
John O L Delancey - One of the best experts on this subject based on the ideXlab platform.
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age effects on Urethral striated muscle i changes in number and diameter of striated muscle fibers in the ventral Urethra
American Journal of Obstetrics and Gynecology, 2002Co-Authors: Daniele Perucchini, John O L Delancey, James A Ashtonmiller, U Peschers, Tripti KatariaAbstract:Abstract OBJECTIVE: This study was undertaken to test the null hypothesis that the number of striated muscle fibers in the ventral wall of the female Urethra remains constant with increasing age. STUDY DESIGN: The Urethra and surrounding tissues from 25 female cadavers, mean age 52 years (±SD 18, range 15-80 years), were selected for this study. Each specimen was divided along the midsagittal plane, and a Masson trichrome histologic section was prepared. A systematic count of striated muscle fibers in the ventral wall was then obtained at each decile of Urethral length. RESULTS: A decrease in the total number of fibers within the sampled area was found with increasing age. The mean of the total fibers across all Urethrae was 17,423 (±SD 9,624, range 4,788-35,867). Over the life span, an average of 364 fibers (2%) were lost per year (95% CI 197-531; P 2 and decreased by 13 fibers/mm 2 per year (95% CI 8-17; P P =.3). CONCLUSIONS: The number and density of Urethral striated muscle fibers decline with age. (Am J Obstet Gynecol 2002;186:351-5.)
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structural support of the Urethra as it relates to stress urinary incontinence the hammock hypothesis
American Journal of Obstetrics and Gynecology, 1994Co-Authors: John O L DelanceyAbstract:Abstract OBJECTIVE: This study examines the anatomic factors that could explain the mechanical basis for transmission of abdominal pressure to the Urethra. STUDY DESIGN: Dissection of 19 embalmed and 42 fresh cadavers and examination of 13 sets of serial pelvic sections were performed to study the structures involved in Urethral support. The effect of simulated increases in abdominal pressure on the pelvic floor and Urethra was observed in fresh specimens. RESULTS: The Urethra lies on a supportive layer that is composed of the endopelvic fascia and the anterior vaginal wall. This layer gains structural stability through its lateral attachment to the arcus tendineus fascia pelvis and levator ani muscle. Pressure from above compresses the Urethra against this hammock-like supportive layer, compressing its lumen closed. The stability of the subUrethral layer depends on the intact connection of the vaginal wall and endopelvic fascia to the arcus tendineus fasciae pelvis and levator ani muscles. CONCLUSION: Increases in Urethral closure pressure during a cough probably arise because the Urethra is compressed against a hammock-like supportive layer, rather than the Urethra being truly "intraabdominal." (AM J Obstet Gynecol 1994;170:1713-23.)
Giovanni Muzzonigro - One of the best experts on this subject based on the ideXlab platform.
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correlation between urodynamics and perineal ultrasound in female patients with urinary incontinence
Neurourology and Urodynamics, 2007Co-Authors: Daniele Minardi, El Z Asmar, Giulio Milanese, Anc Amadi, Vincenzo Piloni, Giovanni MuzzonigroAbstract:Aims We performed urodynamics and perineal ultrasound in female patients with urinary incontinence to assess morphology and function of the bladder base-Urethra complex and of the detrusor muscle, and to find the correlation between these investigations in the diagnosis of (a) bladder neck and Urethral hypermobility and (b) detrusor overactivity; we wanted to compare the tolerabililty of the urodynamic investigation and of the perineal ultrasound. Methods We considered 66 female patients referred to our outpatient clinic for urinary incontinence; we also studied 14 healthy control patients. After accurate case-history collection and physical examination, urodynamic investigation and perineal ultrasound were performed, with recording of parameters specific to both investigations. The statistical analysis was performed by ANOVA, Bonferroni post hoc test, and Spearman correlation test. The tolerability index between the diagnostic investigations performed was assessed by a 3-point scale suggested by the patient. Results In patients with stress incontinence the posterior urethro-vesical angle, the angle of Urethral inclination, and the proximal pubo-Urethral distance are significantly different under stress compared to the resting phase; in patients with urge incontinence, the detrusor wall is thicker and is accompanied by an increase in opening detrusor pressure and detrusor pressure at maximum flow; it is also accompanied by detrusor overactivity with increased Urethral functional length. Increased Urethral functional length is suggested on axial US images by alteration of its normal characteristic target-like appearance with four concentric rings of different echogenicity. In all cases the tolerability of perineal ultrasound has been higher than that of urodynamics. Conclusions There is a good correlation between urodynamic and perineal ultrasound in the diagnosis of bladder neck and Urethral hypermobility; perineal ultrasound can also be useful in the diagnosis of urge incontinence. Functional compressive Urethral obstruction can be diagnosed on the basis of the ultrasound aspect of the Urethral sphincter. Neurourol. Urodynam. 26:176–182, 2007. © 2006 Wiley-Liss, Inc.
