Currently, gastrointestinal segments are considered the gold standard for bladder reconstructive ... more Currently, gastrointestinal segments are considered the gold standard for bladder reconstructive procedures. However, significant complications including chronic urinary tract infection, metabolic abnormalities, urinary stone formation, bowel dysfunction, and secondary malignancies are associated with this approach. Biomaterials derived from silk fibroin may represent a superior alternative due their robust mechanical properties, biodegradable features, and processing plasticity. In the present study, we evaluated the efficacy of a gel spun silk-based matrix for bladder augmentation in a murine model. Over the course of 70 d implantation period, H&E and Masson's trichrome (MTS) analysis revealed that silk matrices were capable of supporting both urothelial and smooth muscle regeneration at the defect site. Prominent uroplakin and contractile protein expression (a-actin, calponin, and SM22a) was evident by immunohistochemical analysis demonstrating maturation of the reconstituted bladder wall compartments. Gel spun silk matrices also elicited a minimal acute inflammatory reaction following 70 d of bladder integration, in contrast to parallel assessments of small intestinal submucosa (SIS) and polyglycolic acid (PGA) matrices which routinely promoted evidence of fibrosis and chronic inflammatory responses. Voided stain on paper analysis revealed that silk augmented animals displayed similar voiding patterns in comparison to non surgical controls by 42 d of implantation. In addition, cystometric evaluations of augmented bladders at 70 d post-op demonstrated that silk scaffolds supported significant increases in bladder capacity and voided volume while maintaining similar degrees of compliance relative to the control group. These results provide evidence for the utility of gel spun silk-based matrices for functional bladder tissue engineering applications.
The natural history of caliceal diverticula in children is unknown. We review our series of child... more The natural history of caliceal diverticula in children is unknown. We review our series of children with caliceal diverticula to examine the presentation, natural history and management. We retrospectively reviewed the records of 22 children presenting with caliceal diverticula between 1983 and 2006. All pertinent clinical data were recorded, including demographics, imaging studies, treatment and clinical outcome. A total of 22 children had 23 caliceal diverticula. There were 14 girls and 8 boys who presented at a mean age of 5.4 +/- 3.1 years (range 0.2 to 12). At clinical presentation 10 patients had febrile urinary tract infection, 2 had hematuria, 2 had abdominal pain, 1 had flank pain and 8 were asymptomatic. Mean diameter of all caliceal diverticula was 2.2 +/- 1.7 cm. All patients underwent voiding cystourethrogram. Two patients (9%) had concomitant ipsilateral caliceal diverticula and vesicoureteral reflux. A total of 10 patients with caliceal diverticula (43%) were treated...
Silk fibroin scaffolds were investigated for their ability to support attachment, proliferation, ... more Silk fibroin scaffolds were investigated for their ability to support attachment, proliferation, and differentiation of human gastrointestinal epithelial and smooth muscle cell lines in order to ascertain their potential for tissue engineering. A bi-layer silk fibroin matrix composed of a porous silk fibroin foam annealed to a homogeneous silk fibroin film was evaluated in parallel with small intestinal submucosa scaffolds. AlamarBlue analysis revealed that silk fibroin scaffolds supported significantly higher levels of small intestinal smooth muscle cell, colon smooth muscle cell, and esophageal smooth muscle cell attachment in comparison to small intestinal submucosa. Following 7 days of culture, relative numbers of each smooth muscle cell population maintained on both scaffold groups were significantly elevated over respective 1-day levels-indicative of cell proliferation. Real-time reverse transcription polymerase chain reaction and immunohistochemical analyses demonstrated that...
Laboratory investigation; a journal of technical methods and pathology, 2006
Urinary bladder outlet obstruction results in sustained stretch of the detrusor muscle and can le... more Urinary bladder outlet obstruction results in sustained stretch of the detrusor muscle and can lead to pathological smooth muscle hyperplasia and hypertrophy. The epidermal growth factor receptor (EGFR) is a cognate receptor for mitogens implicated in bladder hyperplasia/hypertrophy. Here, we investigated the potential for modulation of this pathway by pharmacologic targeting with a clinically available EGFR antagonist using an organ culture model of bladder stretch injury as a test system. Urinary bladders from adult female rats were distended in vivo with medium containing the EGFR inhibitor ZD1839 (gefitinib, Iressa). The bladders were excised and incubated in ex vivo organ culture for 4-24 h. EGFR phosphorylation, DNA proliferation, and the extent of apoptosis in the cultured tissues were assessed. To verify that the smooth muscle cells (SMC) are a target of the EGFR inhibitor, primary culture human and rat bladder SMC were subjected to cyclic mechanical stretch in vitro in the ...
Page 1. 10 The Chemokine System and Arthritis Marlon P. Quinones, Fabio Jimenez, Carlos A. Estrad... more Page 1. 10 The Chemokine System and Arthritis Marlon P. Quinones, Fabio Jimenez, Carlos A. Estrada, Hernan G. Martiniez, and Seema S. Ahuja Summary Rheumatoid arthritis (RA) affects 1% of the US population, or 3 million people. ...
Objectives. To review our experience to better define pediatric renal cell carcinoma (RCC). Pedia... more Objectives. To review our experience to better define pediatric renal cell carcinoma (RCC). Pediatric RCC is rare, and recent data suggest it may be a unique disease. Methods. A retrospective review was conducted of hospital and pathology records from 1965 to 2003. Patients with RCC were identified, and the clinical and pathologic data were extracted. Results. Since 1965, 11 patients with RCC were treated, accounting for 3% of all renal tumors. In the first 20 years, 191 patients with renal tumor were treated, of whom 3 had RCC. In the most recent 15 years, 172 patients with renal tumor were treated, of whom 8 had RCC. The mean age at presentation was 14.7 years (range 9 to 17 years), with a female predominance (2.7:1). The clinical signs and symptoms included hematuria in 36%, flank pain in 27%, and an abdominal mass in 9%; 36% were discovered incidentally. Of the 11 RCC tumors, 45% were papillary and 55% were clear cell carcinoma. Papillary tumors presented at a worse stage and displayed more aggressive clinical behavior. Of 10 patients with available follow-up data, 6 had no evidence of RCC, 1 had died of other causes, 2 had died of metastatic RCC, and 1 was alive with recurrent RCC at a mean follow-up of 4.9 years. Conclusions. The clinical presentation, pathologic characteristics, and clinical behavior of pediatric RCC are different than those for adult RCC. A possible increasing incidence of RCC in children would parallel an increased incidence in adults. Our findings warrant additional and coordinated efforts to better characterize RCC in children. UROLOGY 66: 1296-1300, 2005.
Tricorporal priapism refers to priapism involving the corpora cavernosa and spongiosum. It is exc... more Tricorporal priapism refers to priapism involving the corpora cavernosa and spongiosum. It is exceedingly rare and, depending on the etiology, may be difficult or impossible to treat. We present a case of tricorporal priapism in a patient with metastatic esophageal cancer and complete thrombosis of all venous vasculature below the level of the renal veins. Ultimate management consisted of comfort measures and minimizing the risk of infection. In this case of tricorporal ischemic priapism, the recognized treatment options for ischemic priapism were not applicable, because no viable shunt targets were available. The treating urologist should be aware of this potential clinical entity and be prepared to offer conservative management. UROLOGY 61: 1259xiii-1259xiv, 2003.
The promise of stem cells is to provide a source of non-diseased material for the generation of p... more The promise of stem cells is to provide a source of non-diseased material for the generation of patient-specific cells or tissue for replacement and reconstruction. This review will provide a broad perspective on stem cell research, from the sentinel discoveries to recent developments, and also discuss translational implications.
Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to ... more Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a rabbit model of urethra repair. A bi-layer silk fibroin matrix was fabricated by a solvent-casting/salt leaching process in combination with silk fibroin film casting to generate porous foams buttressed by homogeneous silk fibroin films. Ventral onlay urethroplasty was performed with silk fibroin grafts (Group 1, N = 4) (Width6Length, 162 cm 2 ) in adult male rabbits for 3 m of implantation. Parallel control groups consisted of animals receiving small intestinal submucosa (SIS) implants (Group 2, N = 4) or urethrotomy alone (Group 3, N = 3). Animals in all groups exhibited 100% survival prior to scheduled euthanasia and achieved voluntary voiding following 7 d of initial catheterization. Retrograde urethrography of each implant group at 3 m post-op revealed wide urethral calibers and preservation of organ continuity similar to preoperative and urethrotomy controls with no evidence of contrast extravasation, strictures, fistulas, or stone formation. Histological (hematoxylin and eosin and Masson's trichrome), immunohistochemical, and histomorphometric analyses demonstrated that both silk fibroin and SIS scaffolds promoted similar extents of smooth muscle and epithelial tissue regeneration throughout the original defect sites with prominent contractile protein (a-smooth muscle actin and SM22a) and cytokeratin expression, respectively. De novo innervation and vascularization were also evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Following 3 m post-op, minimal acute inflammatory reactions were elicited by silk fibroin scaffolds characterized by the presence of eosinophil granulocytes while SIS matrices promoted chronic inflammatory responses indicated by mobilization of mononuclear cell infiltrates. The results of this study demonstrate that bi-layer silk fibroin scaffolds represent promising biomaterials for onlay urethroplasty, capable of promoting similar degrees of tissue regeneration in comparison to conventional SIS scaffolds, but with reduced immunogenicity.
Chemotactic factors known as chemokines play an important role in the pathogenesis of Multiple Sc... more Chemotactic factors known as chemokines play an important role in the pathogenesis of Multiple Sclerosis (MS). Transgenic expression of TNFα in the central nervous system (CNS) leads to the development of a demyelinating phenotype (TNFα-induced demyelination; TID) that is highly reminiscent of MS. Little is known about the role of chemokines in TID but insights derived from studying this model might extend our current understanding of MS pathogenesis and complement data derived from the classic autoimmune encephalomyelitis (EAE) model system. Here we show that in TID, chemokines and their receptors were significantly increased during the acute phases of disease. Notably, the CCL2 (MCP-1)-CCR2 axis and the closely related ligand-receptor pair CCR1-CCL3 (MIP-1α) were among the most up-regulated during disease. On the other hand, receptors like CCR3 and CCR4 were not elevated. This significant increase in the levels of chemokines/receptors correlated with robust immune infiltration of the CNS by inflammatory cells, i.e., macrophages, and immune cells particularly T and B cells. Immunostaining and confocal microscopy, along with in vitro studies revealed that astrocytes were a major source of locally produced chemokines and expressed functional chemokine receptors such as CCR2. Using an in vitro system we demonstrate ‡ that expression of CCR2 was functional in astrocytes and that signaling via this receptor lead to activation of NF-kB and Akt and was associated with increased astrocyte survival. Collectively, our data suggests that transgenic murine models of MS are useful to dissect mechanisms of disease and that in these models, up-regulation of chemokines and their receptors may be key determinants in TID.
In patients with stable penile deformity secondary to Peyronie&am... more In patients with stable penile deformity secondary to Peyronie's disease (PD) penile straightening can be achieved with plaque incision or partial excision and grafting. We present our experience with human cadaveric pericardium for tunica albuginea grafting for men undergoing penile reconstruction for Peyronie's disease. We retrospectively reviewed our experience with 40 men with PD who underwent penile straightening with partial plaque excision and grafting using human cadaveric pericardium from January 1999 to January 2003. All 40 men were evaluable for preoperative, operative and postoperative characteristics. Mean postoperative followup was 22.0 months. Mean preoperative penile curvature was 69.1 degrees. Subjectively 36 of the 40 patients (90%) graded preoperative erection as sufficiently rigid for coitus and 100% had sufficiently rigid erection for coitus following intracorporeal papaverine injection. Mean pericardial graft size was 4.9 x 4.8 cm. Postoperatively 39 of the 40 patients (98%) had successful penile straightening, 38 (95%) achieved coitus, 28 (70%) achieved full, unaided erection and 12 (30%) had some degree of erectile dysfunction (ED) requiring pharmacological assistance for intercourse. There were no significant differences in ED risk factors, plaque location, graft size or complications in men who did and did not have ED postoperatively (p >0.05). There were no major complications or graft related adverse events. Human cadaveric pericardium is a safe, readily available and pliable tissue for tunica albuginea grafting following PD plaque incision or partial excision. Careful patient selection must be emphasized and particular attention must be given to deformity stability and preoperative erectile function to maximize surgical outcome.
The mechanisms underlying ureteral cell regulation are largely unknown. Previous studies have ide... more The mechanisms underlying ureteral cell regulation are largely unknown. Previous studies have identified lipid rafts/caveolae as regulators of growth stimulatory signals in ureteral smooth muscle cells (USMCs). In this study we determined whether growth inhibitory signaling by transforming growth factor-beta1 (TGF-beta1) is also regulated by caveolae in USMC. Expression of components of the TGF-beta1 signaling axis in USMCs was determined by immunoblot and mRNA analyses. Growth regulatory activity of TGF-beta1 was assessed by H-thymidine incorporation. In select experiments caveolae were disrupted reversibly by cholesterol depletion and replenishment prior to TGF-beta1 treatment. TGF-beta1-responsive gene expression was evaluated using the TGF-beta1 responsive promoter-reporter construct 3TP-Lux. USMCs expressed TGF-beta1, types I and II TGF-beta1 receptors, and the effector Smad-2. TGF-beta1 potently inhibited DNA synthesis in USMCs (IC50 60 pM). TGF-beta1 mediated DNA synthesis inhibition was potentiated following the disruption of caveolae by cholesterol depletion. This effect was reversible with membrane cholesterol restoration. TGF-beta1 stimulated gene activity was augmented by caveolae disruption, while caveolae reformation returned promoter activity to baseline levels. TGF-beta1 is a potent growth inhibitor of USMCs and its activity can be enhanced by caveolae ablation. These findings suggest a role for TGF-beta1 in the growth regulation of normal ureteral cells and implicate caveolar membrane domains in the negative regulation of TGF-beta1 signaling. These studies may be relevant to ureteral pathologies that are characterized by smooth muscle dysplasia.
We prospectively evaluated the precision of ultrasound and computerized tomography to diagnose ur... more We prospectively evaluated the precision of ultrasound and computerized tomography to diagnose urinary stones in children and determined whether these differences in radiological findings have any impact on clinical management. Materials and Methods: A total of 50 consecutive patients with suspected urolithiasis underwent computerized tomography and ultrasound. Two radiologists reviewed each study independently in blinded fashion. When a difference in findings was detected, 8 pediatric urologists reviewed the case. Clinical management was based on the results of each radiological test independently. Statistical analysis was performed using Fisher's exact test. Results: Compared to computerized tomography ultrasound had 76% sensitivity and 100% specificity. In 8 patients stone(s) seen on computerized tomography was not seen on ultrasound. The average size of missed stones was 2.3 mm. In 7 patients computerized tomography showed stones bilaterally but stone was seen on only 1 side on ultrasound. When evaluating the clinical impact, the ultrasound/computerized tomography discrepancy did not result in any significant change in clinical management except in 4 cases. In these cases ultrasound findings suggested that additional imaging was required and, thus, stone(s) in the distal ureter would have been identified on subsequent imaging. Conclusions: Although computerized tomography is more sensitive for detecting urolithiasis than ultrasound, the difference in usefulness between the 2 radiological tests may not be clinically significant. Given concerns for the potentially harmful cumulative long-term effect of radiation, ultrasound should be considered the first imaging test in children with suspected urolithiasis.
We determined the resolution rate of vesicoureteral reflux and the factors that influence it to f... more We determined the resolution rate of vesicoureteral reflux and the factors that influence it to formulate nomograms to predict the probability of annual resolution for individual cases of reflux. Materials and Methods: We studied 2,462 children with primary vesicoureteral reflux diagnosed between 1998 and 2006. Cox proportional hazards regression was used to model time to resolution as a function of statistically significant demographic and clinical variables. The resulting model was used to construct nomograms predicting the annual cumulative probability of reflux resolution. Results: Multivariate analysis showed that all cases of unilateral reflux resolved earlier than female bilateral reflux (HR 1.42, p Ͻ0.001). Additionally age less than 1 year at presentation (HR 1.31, p Ͻ0.001), lower reflux grade (2.96, p Ͻ0.001 for grade I; 2.28, p Ͻ0.001 for grade II; 1.63, p Ͻ0.001 for grade III), reflux diagnosed on postnatal evaluation for prenatal hydronephrosis or sibling screening (1.24, p ϭ 0.002) and single ureter (1.55, p Ͻ0.001) were associated with significantly earlier resolution of reflux. Specific predicted cumulative probabilities of reflux resolution at annual intervals from diagnosis (1 to 5 years) were calculated for every possible combination of the significant variables. Conclusions: Our analyses demonstrate that resolution of vesicoureteral reflux is dependent on age at presentation, gender, grade, laterality, mode of clinical presentation and ureteral anatomy. We constructed nomogram tables containing estimates of annual reflux resolution rate as a function of these variables. This information is valuable for clinical counseling and management decisions.
One potential strategy for improving voiding diary completion rates and data quality is use of a ... more One potential strategy for improving voiding diary completion rates and data quality is use of a mobile electronic format. We evaluated the acceptability and feasibility of mobile voiding diaries for patients with nonneurogenic lower urinary tract dysfunction, and compared mobile and paper voiding diaries. We prospectively enrolled children presenting with daytime symptoms of lower urinary tract dysfunction between July 2012 and April 2013. We enrolled an initial cohort of patients who were provided a paper voiding diary and a subsequent cohort who were provided a mobile voiding diary. We conducted in person interviews and assessed completion rates and quality, comparing paper and mobile voiding diary groups. We enrolled 45 patients who received a paper voiding diary and 38 who received a mobile voiding diary. Completion rates were 78% for paper voiding diaries and 61% for mobile voiding diaries (p = 0.10). Data quality measures for patients completing paper vs mobile voiding diaries revealed a larger proportion (63% vs 52%) providing a full 5 days of data and a smaller proportion (20% vs 65%) with data gaps. However, the paper voiding diary also demonstrated a lower proportion (80% vs 100%) that was completely legible and a lower proportion (40% vs 65%) with completely prospective data entry. The use of a mobile voiding diary was acceptable and feasible for our patients with lower urinary tract dysfunction, although completion rates were somewhat lower compared to paper voiding diaries. Data quality was not clearly better for either version. The mobile voiding diary format may offer data quality advantages for select groups but it did not display significant superiority when provided universally.
Currently, gastrointestinal segments are considered the gold standard for bladder reconstructive ... more Currently, gastrointestinal segments are considered the gold standard for bladder reconstructive procedures. However, significant complications including chronic urinary tract infection, metabolic abnormalities, urinary stone formation, bowel dysfunction, and secondary malignancies are associated with this approach. Biomaterials derived from silk fibroin may represent a superior alternative due their robust mechanical properties, biodegradable features, and processing plasticity. In the present study, we evaluated the efficacy of a gel spun silk-based matrix for bladder augmentation in a murine model. Over the course of 70 d implantation period, H&E and Masson's trichrome (MTS) analysis revealed that silk matrices were capable of supporting both urothelial and smooth muscle regeneration at the defect site. Prominent uroplakin and contractile protein expression (a-actin, calponin, and SM22a) was evident by immunohistochemical analysis demonstrating maturation of the reconstituted bladder wall compartments. Gel spun silk matrices also elicited a minimal acute inflammatory reaction following 70 d of bladder integration, in contrast to parallel assessments of small intestinal submucosa (SIS) and polyglycolic acid (PGA) matrices which routinely promoted evidence of fibrosis and chronic inflammatory responses. Voided stain on paper analysis revealed that silk augmented animals displayed similar voiding patterns in comparison to non surgical controls by 42 d of implantation. In addition, cystometric evaluations of augmented bladders at 70 d post-op demonstrated that silk scaffolds supported significant increases in bladder capacity and voided volume while maintaining similar degrees of compliance relative to the control group. These results provide evidence for the utility of gel spun silk-based matrices for functional bladder tissue engineering applications.
The natural history of caliceal diverticula in children is unknown. We review our series of child... more The natural history of caliceal diverticula in children is unknown. We review our series of children with caliceal diverticula to examine the presentation, natural history and management. We retrospectively reviewed the records of 22 children presenting with caliceal diverticula between 1983 and 2006. All pertinent clinical data were recorded, including demographics, imaging studies, treatment and clinical outcome. A total of 22 children had 23 caliceal diverticula. There were 14 girls and 8 boys who presented at a mean age of 5.4 +/- 3.1 years (range 0.2 to 12). At clinical presentation 10 patients had febrile urinary tract infection, 2 had hematuria, 2 had abdominal pain, 1 had flank pain and 8 were asymptomatic. Mean diameter of all caliceal diverticula was 2.2 +/- 1.7 cm. All patients underwent voiding cystourethrogram. Two patients (9%) had concomitant ipsilateral caliceal diverticula and vesicoureteral reflux. A total of 10 patients with caliceal diverticula (43%) were treated...
Silk fibroin scaffolds were investigated for their ability to support attachment, proliferation, ... more Silk fibroin scaffolds were investigated for their ability to support attachment, proliferation, and differentiation of human gastrointestinal epithelial and smooth muscle cell lines in order to ascertain their potential for tissue engineering. A bi-layer silk fibroin matrix composed of a porous silk fibroin foam annealed to a homogeneous silk fibroin film was evaluated in parallel with small intestinal submucosa scaffolds. AlamarBlue analysis revealed that silk fibroin scaffolds supported significantly higher levels of small intestinal smooth muscle cell, colon smooth muscle cell, and esophageal smooth muscle cell attachment in comparison to small intestinal submucosa. Following 7 days of culture, relative numbers of each smooth muscle cell population maintained on both scaffold groups were significantly elevated over respective 1-day levels-indicative of cell proliferation. Real-time reverse transcription polymerase chain reaction and immunohistochemical analyses demonstrated that...
Laboratory investigation; a journal of technical methods and pathology, 2006
Urinary bladder outlet obstruction results in sustained stretch of the detrusor muscle and can le... more Urinary bladder outlet obstruction results in sustained stretch of the detrusor muscle and can lead to pathological smooth muscle hyperplasia and hypertrophy. The epidermal growth factor receptor (EGFR) is a cognate receptor for mitogens implicated in bladder hyperplasia/hypertrophy. Here, we investigated the potential for modulation of this pathway by pharmacologic targeting with a clinically available EGFR antagonist using an organ culture model of bladder stretch injury as a test system. Urinary bladders from adult female rats were distended in vivo with medium containing the EGFR inhibitor ZD1839 (gefitinib, Iressa). The bladders were excised and incubated in ex vivo organ culture for 4-24 h. EGFR phosphorylation, DNA proliferation, and the extent of apoptosis in the cultured tissues were assessed. To verify that the smooth muscle cells (SMC) are a target of the EGFR inhibitor, primary culture human and rat bladder SMC were subjected to cyclic mechanical stretch in vitro in the ...
Page 1. 10 The Chemokine System and Arthritis Marlon P. Quinones, Fabio Jimenez, Carlos A. Estrad... more Page 1. 10 The Chemokine System and Arthritis Marlon P. Quinones, Fabio Jimenez, Carlos A. Estrada, Hernan G. Martiniez, and Seema S. Ahuja Summary Rheumatoid arthritis (RA) affects 1% of the US population, or 3 million people. ...
Objectives. To review our experience to better define pediatric renal cell carcinoma (RCC). Pedia... more Objectives. To review our experience to better define pediatric renal cell carcinoma (RCC). Pediatric RCC is rare, and recent data suggest it may be a unique disease. Methods. A retrospective review was conducted of hospital and pathology records from 1965 to 2003. Patients with RCC were identified, and the clinical and pathologic data were extracted. Results. Since 1965, 11 patients with RCC were treated, accounting for 3% of all renal tumors. In the first 20 years, 191 patients with renal tumor were treated, of whom 3 had RCC. In the most recent 15 years, 172 patients with renal tumor were treated, of whom 8 had RCC. The mean age at presentation was 14.7 years (range 9 to 17 years), with a female predominance (2.7:1). The clinical signs and symptoms included hematuria in 36%, flank pain in 27%, and an abdominal mass in 9%; 36% were discovered incidentally. Of the 11 RCC tumors, 45% were papillary and 55% were clear cell carcinoma. Papillary tumors presented at a worse stage and displayed more aggressive clinical behavior. Of 10 patients with available follow-up data, 6 had no evidence of RCC, 1 had died of other causes, 2 had died of metastatic RCC, and 1 was alive with recurrent RCC at a mean follow-up of 4.9 years. Conclusions. The clinical presentation, pathologic characteristics, and clinical behavior of pediatric RCC are different than those for adult RCC. A possible increasing incidence of RCC in children would parallel an increased incidence in adults. Our findings warrant additional and coordinated efforts to better characterize RCC in children. UROLOGY 66: 1296-1300, 2005.
Tricorporal priapism refers to priapism involving the corpora cavernosa and spongiosum. It is exc... more Tricorporal priapism refers to priapism involving the corpora cavernosa and spongiosum. It is exceedingly rare and, depending on the etiology, may be difficult or impossible to treat. We present a case of tricorporal priapism in a patient with metastatic esophageal cancer and complete thrombosis of all venous vasculature below the level of the renal veins. Ultimate management consisted of comfort measures and minimizing the risk of infection. In this case of tricorporal ischemic priapism, the recognized treatment options for ischemic priapism were not applicable, because no viable shunt targets were available. The treating urologist should be aware of this potential clinical entity and be prepared to offer conservative management. UROLOGY 61: 1259xiii-1259xiv, 2003.
The promise of stem cells is to provide a source of non-diseased material for the generation of p... more The promise of stem cells is to provide a source of non-diseased material for the generation of patient-specific cells or tissue for replacement and reconstruction. This review will provide a broad perspective on stem cell research, from the sentinel discoveries to recent developments, and also discuss translational implications.
Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to ... more Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a rabbit model of urethra repair. A bi-layer silk fibroin matrix was fabricated by a solvent-casting/salt leaching process in combination with silk fibroin film casting to generate porous foams buttressed by homogeneous silk fibroin films. Ventral onlay urethroplasty was performed with silk fibroin grafts (Group 1, N = 4) (Width6Length, 162 cm 2 ) in adult male rabbits for 3 m of implantation. Parallel control groups consisted of animals receiving small intestinal submucosa (SIS) implants (Group 2, N = 4) or urethrotomy alone (Group 3, N = 3). Animals in all groups exhibited 100% survival prior to scheduled euthanasia and achieved voluntary voiding following 7 d of initial catheterization. Retrograde urethrography of each implant group at 3 m post-op revealed wide urethral calibers and preservation of organ continuity similar to preoperative and urethrotomy controls with no evidence of contrast extravasation, strictures, fistulas, or stone formation. Histological (hematoxylin and eosin and Masson's trichrome), immunohistochemical, and histomorphometric analyses demonstrated that both silk fibroin and SIS scaffolds promoted similar extents of smooth muscle and epithelial tissue regeneration throughout the original defect sites with prominent contractile protein (a-smooth muscle actin and SM22a) and cytokeratin expression, respectively. De novo innervation and vascularization were also evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Following 3 m post-op, minimal acute inflammatory reactions were elicited by silk fibroin scaffolds characterized by the presence of eosinophil granulocytes while SIS matrices promoted chronic inflammatory responses indicated by mobilization of mononuclear cell infiltrates. The results of this study demonstrate that bi-layer silk fibroin scaffolds represent promising biomaterials for onlay urethroplasty, capable of promoting similar degrees of tissue regeneration in comparison to conventional SIS scaffolds, but with reduced immunogenicity.
Chemotactic factors known as chemokines play an important role in the pathogenesis of Multiple Sc... more Chemotactic factors known as chemokines play an important role in the pathogenesis of Multiple Sclerosis (MS). Transgenic expression of TNFα in the central nervous system (CNS) leads to the development of a demyelinating phenotype (TNFα-induced demyelination; TID) that is highly reminiscent of MS. Little is known about the role of chemokines in TID but insights derived from studying this model might extend our current understanding of MS pathogenesis and complement data derived from the classic autoimmune encephalomyelitis (EAE) model system. Here we show that in TID, chemokines and their receptors were significantly increased during the acute phases of disease. Notably, the CCL2 (MCP-1)-CCR2 axis and the closely related ligand-receptor pair CCR1-CCL3 (MIP-1α) were among the most up-regulated during disease. On the other hand, receptors like CCR3 and CCR4 were not elevated. This significant increase in the levels of chemokines/receptors correlated with robust immune infiltration of the CNS by inflammatory cells, i.e., macrophages, and immune cells particularly T and B cells. Immunostaining and confocal microscopy, along with in vitro studies revealed that astrocytes were a major source of locally produced chemokines and expressed functional chemokine receptors such as CCR2. Using an in vitro system we demonstrate ‡ that expression of CCR2 was functional in astrocytes and that signaling via this receptor lead to activation of NF-kB and Akt and was associated with increased astrocyte survival. Collectively, our data suggests that transgenic murine models of MS are useful to dissect mechanisms of disease and that in these models, up-regulation of chemokines and their receptors may be key determinants in TID.
In patients with stable penile deformity secondary to Peyronie&am... more In patients with stable penile deformity secondary to Peyronie's disease (PD) penile straightening can be achieved with plaque incision or partial excision and grafting. We present our experience with human cadaveric pericardium for tunica albuginea grafting for men undergoing penile reconstruction for Peyronie's disease. We retrospectively reviewed our experience with 40 men with PD who underwent penile straightening with partial plaque excision and grafting using human cadaveric pericardium from January 1999 to January 2003. All 40 men were evaluable for preoperative, operative and postoperative characteristics. Mean postoperative followup was 22.0 months. Mean preoperative penile curvature was 69.1 degrees. Subjectively 36 of the 40 patients (90%) graded preoperative erection as sufficiently rigid for coitus and 100% had sufficiently rigid erection for coitus following intracorporeal papaverine injection. Mean pericardial graft size was 4.9 x 4.8 cm. Postoperatively 39 of the 40 patients (98%) had successful penile straightening, 38 (95%) achieved coitus, 28 (70%) achieved full, unaided erection and 12 (30%) had some degree of erectile dysfunction (ED) requiring pharmacological assistance for intercourse. There were no significant differences in ED risk factors, plaque location, graft size or complications in men who did and did not have ED postoperatively (p >0.05). There were no major complications or graft related adverse events. Human cadaveric pericardium is a safe, readily available and pliable tissue for tunica albuginea grafting following PD plaque incision or partial excision. Careful patient selection must be emphasized and particular attention must be given to deformity stability and preoperative erectile function to maximize surgical outcome.
The mechanisms underlying ureteral cell regulation are largely unknown. Previous studies have ide... more The mechanisms underlying ureteral cell regulation are largely unknown. Previous studies have identified lipid rafts/caveolae as regulators of growth stimulatory signals in ureteral smooth muscle cells (USMCs). In this study we determined whether growth inhibitory signaling by transforming growth factor-beta1 (TGF-beta1) is also regulated by caveolae in USMC. Expression of components of the TGF-beta1 signaling axis in USMCs was determined by immunoblot and mRNA analyses. Growth regulatory activity of TGF-beta1 was assessed by H-thymidine incorporation. In select experiments caveolae were disrupted reversibly by cholesterol depletion and replenishment prior to TGF-beta1 treatment. TGF-beta1-responsive gene expression was evaluated using the TGF-beta1 responsive promoter-reporter construct 3TP-Lux. USMCs expressed TGF-beta1, types I and II TGF-beta1 receptors, and the effector Smad-2. TGF-beta1 potently inhibited DNA synthesis in USMCs (IC50 60 pM). TGF-beta1 mediated DNA synthesis inhibition was potentiated following the disruption of caveolae by cholesterol depletion. This effect was reversible with membrane cholesterol restoration. TGF-beta1 stimulated gene activity was augmented by caveolae disruption, while caveolae reformation returned promoter activity to baseline levels. TGF-beta1 is a potent growth inhibitor of USMCs and its activity can be enhanced by caveolae ablation. These findings suggest a role for TGF-beta1 in the growth regulation of normal ureteral cells and implicate caveolar membrane domains in the negative regulation of TGF-beta1 signaling. These studies may be relevant to ureteral pathologies that are characterized by smooth muscle dysplasia.
We prospectively evaluated the precision of ultrasound and computerized tomography to diagnose ur... more We prospectively evaluated the precision of ultrasound and computerized tomography to diagnose urinary stones in children and determined whether these differences in radiological findings have any impact on clinical management. Materials and Methods: A total of 50 consecutive patients with suspected urolithiasis underwent computerized tomography and ultrasound. Two radiologists reviewed each study independently in blinded fashion. When a difference in findings was detected, 8 pediatric urologists reviewed the case. Clinical management was based on the results of each radiological test independently. Statistical analysis was performed using Fisher's exact test. Results: Compared to computerized tomography ultrasound had 76% sensitivity and 100% specificity. In 8 patients stone(s) seen on computerized tomography was not seen on ultrasound. The average size of missed stones was 2.3 mm. In 7 patients computerized tomography showed stones bilaterally but stone was seen on only 1 side on ultrasound. When evaluating the clinical impact, the ultrasound/computerized tomography discrepancy did not result in any significant change in clinical management except in 4 cases. In these cases ultrasound findings suggested that additional imaging was required and, thus, stone(s) in the distal ureter would have been identified on subsequent imaging. Conclusions: Although computerized tomography is more sensitive for detecting urolithiasis than ultrasound, the difference in usefulness between the 2 radiological tests may not be clinically significant. Given concerns for the potentially harmful cumulative long-term effect of radiation, ultrasound should be considered the first imaging test in children with suspected urolithiasis.
We determined the resolution rate of vesicoureteral reflux and the factors that influence it to f... more We determined the resolution rate of vesicoureteral reflux and the factors that influence it to formulate nomograms to predict the probability of annual resolution for individual cases of reflux. Materials and Methods: We studied 2,462 children with primary vesicoureteral reflux diagnosed between 1998 and 2006. Cox proportional hazards regression was used to model time to resolution as a function of statistically significant demographic and clinical variables. The resulting model was used to construct nomograms predicting the annual cumulative probability of reflux resolution. Results: Multivariate analysis showed that all cases of unilateral reflux resolved earlier than female bilateral reflux (HR 1.42, p Ͻ0.001). Additionally age less than 1 year at presentation (HR 1.31, p Ͻ0.001), lower reflux grade (2.96, p Ͻ0.001 for grade I; 2.28, p Ͻ0.001 for grade II; 1.63, p Ͻ0.001 for grade III), reflux diagnosed on postnatal evaluation for prenatal hydronephrosis or sibling screening (1.24, p ϭ 0.002) and single ureter (1.55, p Ͻ0.001) were associated with significantly earlier resolution of reflux. Specific predicted cumulative probabilities of reflux resolution at annual intervals from diagnosis (1 to 5 years) were calculated for every possible combination of the significant variables. Conclusions: Our analyses demonstrate that resolution of vesicoureteral reflux is dependent on age at presentation, gender, grade, laterality, mode of clinical presentation and ureteral anatomy. We constructed nomogram tables containing estimates of annual reflux resolution rate as a function of these variables. This information is valuable for clinical counseling and management decisions.
One potential strategy for improving voiding diary completion rates and data quality is use of a ... more One potential strategy for improving voiding diary completion rates and data quality is use of a mobile electronic format. We evaluated the acceptability and feasibility of mobile voiding diaries for patients with nonneurogenic lower urinary tract dysfunction, and compared mobile and paper voiding diaries. We prospectively enrolled children presenting with daytime symptoms of lower urinary tract dysfunction between July 2012 and April 2013. We enrolled an initial cohort of patients who were provided a paper voiding diary and a subsequent cohort who were provided a mobile voiding diary. We conducted in person interviews and assessed completion rates and quality, comparing paper and mobile voiding diary groups. We enrolled 45 patients who received a paper voiding diary and 38 who received a mobile voiding diary. Completion rates were 78% for paper voiding diaries and 61% for mobile voiding diaries (p = 0.10). Data quality measures for patients completing paper vs mobile voiding diaries revealed a larger proportion (63% vs 52%) providing a full 5 days of data and a smaller proportion (20% vs 65%) with data gaps. However, the paper voiding diary also demonstrated a lower proportion (80% vs 100%) that was completely legible and a lower proportion (40% vs 65%) with completely prospective data entry. The use of a mobile voiding diary was acceptable and feasible for our patients with lower urinary tract dysfunction, although completion rates were somewhat lower compared to paper voiding diaries. Data quality was not clearly better for either version. The mobile voiding diary format may offer data quality advantages for select groups but it did not display significant superiority when provided universally.
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Papers by Carlos Estrada