Scaling laws for step bunching on vicinal surfaces: Role of the dynamical and chemical effects.

We study the evolution of step bunches on vicinal surfaces using a thermodynamically consistent step-flow model. By accounting for the dynamics of adatom diffusion on terraces and attachment-detachment at steps (referred to collectively as the dynamical effect), this model circumvents the quasistatic approximation that prevails in the literature. Furthermore, it generalizes the expression of the step chemical potential by incorporating the necessary coupling between the diffusion fields on adjacent terraces (referred to as the chemical effect). Having previously shown that these dynamical and chemical effects can explain the onset of step bunching without recourse to the inverse Ehrlich-Schwoebel (iES) barrier or other extraneous mechanisms, we are here interested in the evolution of step bunches beyond the linear-stability regime. In particular, the numerical resolution of the step-flow free boundary problem yields a robust power-law coarsening of the surface profile, with the bunch height growing in time as H∼t^{1/2} and the minimal interstep distance as a function of the number of steps in the bunch cell obeying ℓ_{min}∼N^{-2/3}. Although these exponents have previously been reported, the novelty of the present approach is that these scaling laws are obtained in the absence of an iES barrier or adatom electromigration. In order to validate our simulations, we take the continuum limit of the discrete step-flow system via Taylor expansions with respect to the terrace size, leading to a novel nonlinear evolution equation for the surface height. We investigate the existence of self-similar solutions of this equation and confirm the 1/2 coarsening exponent obtained numerically for H. We highlight the influence of the combined dynamical-chemical effect and show that it can be interpreted as an effective iES barrier in the setting of the standard Burton-Cabrera-Frank theory. Finally, we use a Padé approximant to derive an analytical expression for the velocity of steadily moving step bunches and compare it to numerical simulations.

Economic analysis of healthcare-associated infection prevention and control interventions in medical and surgical units: systematic review using a discounting approach.

Nosocomial or healthcare-associated infections (HCAIs) are associated with a financial burden that affects both patients and healthcare institutions worldwide. The clinical best care practices (CBPs) of hand hygiene, hygiene and sanitation, screening, and basic and additional precautions aim to reduce this burden. The COVID-19 pandemic has confirmed these four CBPs are critically important prevention practices that limit the spread of HCAIs. This paper conducted a systematic review of economic evaluations related to these four CBPs using a discounting approach. We searched for articles published between 2000 and 2019. We included economic evaluations of infection prevention and control of Clostridioides difficile-associated diarrhoea, meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and carbapenem-resistant Gram-negative bacilli. Results were analysed with cost-minimization, cost-effectiveness, cost-utility, cost-benefit and cost-consequence analyses. Articles were assessed for quality. A total of 11,898 articles were screened and seven were included. Most studies (4/7) were of overall moderate quality. All studies demonstrated cost effectiveness of CBPs. The average yearly net cost savings from the CBPs ranged from $252,847 (2019 Canadian dollars) to $1,691,823, depending on the rate of discount (3% and 8%). The average incremental benefit cost ratio of CBPs varied from 2.48 to 7.66. In order to make efficient use of resources and maximize health benefits, ongoing research in the economic evaluation of infection control should be carried out to support evidence-based healthcare policy decisions.

Stability of Vicinal Surfaces: Beyond the Quasistatic Approximation.

We revisit the step bunching instability without recourse to the quasistatic approximation and show that the stability diagrams are significantly altered, even in the low-deposition regime where it was thought sufficient. In particular, steps are unstable against bunching for attachment-detachment limited growth. By accounting for the dynamics and chemical effects, we can explain the onset of step bunching in Si(111)-(7×7) and GaAs(001) without resort to the inverse Schwoebel barrier or step-edge diffusion. Further, the size-scaling analysis of step-bunch growth, as induced by these two combined effects, agrees with the bunching regime observed at 750 °C in Si(111)-(7×7).

Synthesis and biological evaluation of novel 2 (4`-hydroxynaphthyl) chromen-4-one as a CK2 inhibitor.

Protein kinase CK2 is a potential drug target for many diseases including cancer, inflammatory disorders, Alzheimer's disease, Parkinson's disease and viral infections. Significant efforts have been made for the discovery of potent inhibitors of this enzyme. Herein, we report on the synthesis, characterization, and biological evaluation of novel flavonoid compounds as CK2 inhibitors. The tested compounds were 2 (4`-hydroxynaphthyl) chromen-4-one which is a naphthyl backbone flavonoid with an IC50 value of 0.45±0.059 µM and 2(4-hydroxyphenyl)-4H-chromen-4-one a phenyl based derivative with an IC50 value of 0.33±0.048 µM. Cell viability was tested using MCF-7 cells. Both compounds were able to reduce the cell viability around 50 % in concentration of 100 µM after 48 h. Molecular modeling studies were performed to understand the binding mode of both compounds.

The immune microenvironment in cutaneous leishmaniasis.

BACKGROUND: Cutaneous leishmaniasis is an infection that has spread to non-endemic regions, stimulating recent interest for the enhanced understanding of this disease. Downregulation of the CD1a receptor on Langerhans cells has been described in various cutaneous infections. OBJECTIVE: In this study, the immune response across different Ridley patterns and parasitic indices is outlined in a case series of cutaneous leishmaniasis. METHODS: Skin punch biopsies from the interface of normal and lesional cutaneous leishmaniasis were collected from 33 patients with molecularly confirmed Leishmania tropica or L. major infection. Ridley patterns (2-5) were assessed for various clinicopathological features including age, gender, disease duration, parasitic index and constituents of the inflammatory infiltrate. CD1a, CD68, CD3, CD4, CD8, CD20 and CD138 stains were performed on normal skin tissue, cutaneous leishmaniasis biopsies and cytospin/cell block cytology preparations of cultured leishmania promastigotes. CD1a was quantified per mm2 in the epidermis and dermis. The remaining stains were graded according to a 4-tiered grading system [0 (0-4%); 1 (5-24%); 2 (25-49%); 3 (50-74%) and 4 (75-100%). RESULTS: Total CD1a expression significantly decreased (14-fold) from parasitic indices (0-2) to (5-6); (ρ < 0.001). CD1a expression in the epidermis was at least 5-fold lower than normal skin (58 vs. 400 cells/mm2), inversely correlating with the parasitic index. There was an increase in dermal CD1a Langerhans cells (33 vs. 0 cells/mm² in the dermis). CD1a and CD68 staining of amastigotes was strong and diffuse, whereas promastigotes were negative. The major inflammatory infiltrate, in all Ridley patterns, consisted of macrophages and double-negative CD3(+) CD4(-) CD8(-) T lymphocytes. The double-negative CD3 T cells formed a ring around the parasitic laden macrophages. Apart from CD1a, there was no significant difference in inflammatory markers between the various Ridley patterns and parasitic indices. Disease duration did not correlate with Ridley pattern. CONCLUSION: The significant decrease in CD1a expression is postulated by two mechanisms; either via direct CD1a receptor uptake by leishmania amastigotes and/or negative feedback inhibition of CD1a Langerhans cells by double-negative CD3 T-regulatory cells. Modulation of the immune microenvironment in cutaneous leishmaniasis represents a potential therapeutic and prophylactic target.

Primary effusion lymphoma in an elderly patient effectively treated by lenalidomide: case report and review of literature.

Primary effusion lymphoma (PEL) is a rare aggressive subset of non-Hodgkin B-cell lymphoma. It is caused by Kaposi sarcoma-associated herpesvirus/human herpesvirus type 8 (KSHV/HHV8). It occurs mainly, but not exclusively, in HIV-positive patients. PEL predominantly develops in serous cavities and occasionally in extracavitary regions. PEL carries a very poor prognosis with a median survival time of <6 months. Indeed, currently used treatment modalities such as CHOP chemotherapy are far from achieving complete and sustainable remission. Therefore, there is no clear standard of care established in the treatment of PEL patients, stressing the need for novel-targeted approaches. Here, we have attempted a comprehensive assessment of the treatment of PEL, discussed avant-garde therapies and updated the state of preclinical research with promising clinical applications in the field. These include inhibitors of viral replication, modulators of cell signaling and inflammation, nuclear factor kappa B (NF-κB) and histone deacetylase inhibitors, and recently the combination of arsenic trioxide and interferon-alpha. Some of these targeted therapies have not yet reached clinical studies, although others were used in a few individual case reports with low numbers of patients. We also describe the first case of a 77-year-old, HIV-negative, HHV8-positive patient diagnosed with PEL limited to the pleural and peritoneal cavities. He received lenalidomide 25 mg/day for 21 days every 28 days. Treatment was well tolerated with no side effects. He rapidly improved after 1 month of treatment and progressively achieved complete remission persistent after 18 months of therapy. We believe that this review will bridge an important gap between classical chemotherapy and modern approaches of targeted therapy. Finally, our findings warrant further evaluation of lenalidomide in future prospective clinical studies.

Baseline determinants of global diet quality in older men and women from the NuAge cohort.

UNLABELLED: Judicious food choices are of prime importance during aging. OBJECTIVES: This study was conducted to identify individual and collective attributes determining global diet quality (DQ). METHODOLOGY: Participants were 1,793 adults (52% women) from the NuAge study on nutrition and successful aging. Subjects aged 67 to 84 years in relatively good health were recruited from the Québec Medicare Database. Sociodemographic, affective, and cognitive data, health conditions, perceived physical health and functional status, dietary habits and dietary attributes and community resources were obtained using questionnaires. Body weight and height were measured and body mass index (BMI) was calculated. Three non-consecutive 24-hour diet recalls were collected at recruitment. DQ, assessed using the Canadian Healthy Eating Index (C-HEI, /100), was computed on the mean intakes from the diet recalls. Analyses were stratified by gender. Variables significantly related to DQ in bivariate analyses (p<.05) were entered into backward stepwise multiple regression analyses. RESULTS: Among men, the final model showed higher education (ß=0.23, p=.01), diet knowledge (ß=0.96, p<.0001), number of daily meals (ß=1.91, p=.02) and perceived physical health (ß=0.06, p=.01) to be positive determinants of DQ, whereas alcohol consumption (ß=-2.25, p=.05), wearing dentures (ß=-2.31, p=.01) and eating regularly in restaurants (ß=-1.65, p=.03) were negative determinants of DQ (adjusted R2 = 13.7%). Among women, higher education (ß=0.29, p=.002), diet knowledge (ß=0.54, p=.002), number of daily meals (ß=3.61, p<.0001), and hunger (ß=0.61, p<.0001) were positive determinants of global DQ; greater BMI (ß=-0.16, p=.03) and chewing problems (ß=-0.48, p=.03) were negative determinants of DQ (adjusted R2 = 7.8%). DISCUSSION: These results point to several key factors influencing global DQ in older adults and also show gender-based differences. More research must be done to better understand how these factors change with aging and exert their impact on diet, particularly since variance in DQ was largely unexplained. As diet knowledge was an independent predictor for both genders, targeted, sustainable interventions are needed to ensure good diet quality as people age.

Hematopoietic SCT for adult T-cell leukemia/lymphoma: a review.

Adult T-cell leukemia/lymphoma is a T-cell malignancy caused by the human T-cell lymphotropic virus type 1. The aggressive forms of the disease carry a poor prognosis with standard therapies. The role of high-dose treatment with blood and marrow transplantation has, therefore, been examined mainly by Japanese groups in the form of retrospective studies. In this study, we review the literature, discuss some of the challenges facing successful transplantation approaches and stress the need for more innovative studies including in the Western hemisphere.

Endoscopic removal of a bleeding colonic polypoid angiodysplasia: case report.

Arteriovenous malformations are common causes of lower gastrointestinal bleeding in the elderly. Among them, angiodysplasia is one subtype that appears on endoscopy as red, flat superficial lesions, and sometimes slightly elevated. Colonic angiodysplasia is very rarely seen as a polypoid lesion. The present case describes a bleeding large polypoid colonic angiodysplasia in a 60-year-old man. It was removed endoscopically using a PolyLoop ligature device without complications.

Homotopic dynamics of telomeric loops in mammalian chromatids.

Asymmetric transfer of a solitonic kink between telomeric loops shared by template-replica chromatids is conceptualized in terms of homotopic dynamics. Downscaled to B-Z DNA these ideas lead to interesting possibilities regarding duplication and/or selective activation of genes located at or near DNA "hybrid" chiralities.

[Conservative treatment of upper urinary tract tumors]. / Traitement conservateur des tumeurs des voies excrétrices supérieures.

The histological appearance and the clinical behaviour of upper urinary tract urothelial tumours are almost identical to those of the bladder. Superficial papillary tumours rarely progress and turn to invasive disease despite a high frequency of recurrence. Technical developments in the endourology field have allowed full endoscopic access to upper tract tumours. Endoscopic resection or ablation of the tumour can be undertaken safely and effectively through ureteroscopy or percutaneous nephroscopy with low risk of extra-renal tumour seeding. For superficial (Ta, T1), low grade (I, II) tumours, a conservative approach can be selected without compromising survival and prognosis. For muscle invasive > T2 or high grade (III) tumours, nephroureterectomy remains the treatment of choice. Intracavitary BCG used after percutaneous resection reduces the risk of recurrence of upper tract urothelial tumours regardless of the grade. Finally, the world literature and our personal experience have shown that the tumour grade and stage are the two independent factors that affect survival of patients with upper urinary tract tumours.

Endopyelotomy failure is associated with reduced urinary transforming growth factor-beta1 levels in patients with upper urinary tract obstruction.

BACKGROUND AND PURPOSE: We previously demonstrated that obstructed ureteropelvic junction (UPJ) segments from patients who had secondary pyeloplasty after endopyelotomy failure expressed transforming growth factor-beta1 (TGF-beta1) at levels significantly lower than patients who had primary pyeloplasty. In order to determine whether these differences in secreted TGF-beta1 are detectable preoperatively in the urine, the TGF-beta1 concentration of urine from patients undergoing endopyelotomy was determined and compared with that from subjects without urologic disease. MATERIALS AND METHODS: Bladder and renal pelvic urine from the obstructed side was obtained from patients (N = 34) undergoing primary endopyelotomy for UPJ obstruction. Bladder urine was also obtained from sex- and age-matched patients (N = 26) having no evidence of urinary tract obstruction. The TGF-beta1 concentration was determined by ELISA and normalized to the creatinine concentration. RESULTS: The bladder urine TGF-beta1 concentration was significantly (P < 0.02) higher in patients with UPJ obstruction (86.1+/-20.5 pg/mg of creatinine) than in those without obstruction (29.7+/-8.0 pg/mg creatinine). The TGF-beta1 concentration in the bladder urine of patients who underwent endopyelotomy and later returned because of UPJ obstruction (25.7+/-12.3 pg/mg of creatinine; N = 6) was not significantly different from the value in unobstructed patients but was significantly lower (P < 0.01) than in patients for whom endopyelotomy was successful (100+/-24.29 pg/mg of creatinine; N = 28). The renal pelvic urinary TGF-beta1 concentration was higher in patients for whom endopyelotomy was successful (772+/-490.1 pg/mg of creatinine) than in patients who underwent endopyelotomy and later returned because of UPJ obstruction (126.1+/-41.9 pg/mg of creatinine). CONCLUSIONS: These data suggest that preoperative concentration of TGF-beta1 in the bladder urine of patients with UPJ obstruction who fail endopyelotomy is not significantly different from that in subjects with no urologic disease and significantly lower than in those patients for whom endopyelotomy is successful. Thus, the preoperative bladder urine concentration of TGF-beta1 may assist in selecting patients for this operation, although further investigation is necessary.

Percutaneous implantation of subcutaneous prosthetic ureters: long-term outcome.

PURPOSE: We have used an extra-anatomic subcutaneous alloplastic ureteral replacement initially to bypass ureteral obstruction secondary to advanced pelvic malignancies in patients with a short life expectancy. Following the encouraging preliminary results, our list of indications has broadened to include complex benign ureteral strictures. We herein report the long-term outcome. PATIENTS AND METHODS: A series of 35 subcutaneous prosthetic ureters were implanted percutaneously in 27 patients (19 unilateral and 8 bilateral) to bypass extrinsic ureteral obstructions. The nature of obstruction was neoplastic in 22 patients and benign in 5. A composite prosthesis, consisting of two coaxial tubes--internal pure smooth silicone covered by coiled e-PTFE--has been designed to serve as the ureteral replacement. This tube is inserted percutaneously into the renal pelvis, tunnelled subcutaneously, and introduced through a small suprapubic incision in the bladder. All patients were followed to date or until death from tumor. The mean follow-up was 6.3 months for the deceased patients and 47 months for the surviving ones, the longest follow-up being 84 months. RESULTS: No operative or immediate postoperative deaths were observed. Initial difficulty in placing the prosthesis was encountered in 5 of the 27 patients (19%). Secondary parietal complications occurred in 8.5% of cases (3/35). The prosthetic ureter had to be removed in one patient because of skin erosion. Return to a standard percutaneous nephrostomy was needed in two patients because of local tumor progression with bladder fistulae. Five patients are alive with the prosthesis in place and a follow-up as long as 84 months without encrustation, infection, obstruction, or skin problems and with normally functioning kidneys. CONCLUSION: The subcutaneous urinary diversion using a silicone-PTFE prosthesis is an efficient and minimally invasive way to bypass malignant or complex benign obstructions of the ureters that otherwise would necessitate permanent nephrostomy drainage.

Hand-assisted laparoscopic live donor nephrectomy in a patient with renal artery aneurysm.

Among the transplantation teams there is an increasing interest in laparoscopic live donor nephrectomy. For technical reasons, the use of the left kidney is recommended. However, considering the shortage of organ donors, it is likely that right-side laparoscopic live donor nephrectomy will need to be considered in selected donors, even those with vascular anomalies. Here we report the first case of right-side live donor laparoscopic nephrectomy in a patient with a renal artery aneurysm. Arteriography showed a 3-cm saccular aneurysm of the main right renal artery located at the bifurcation of the secondary branches and associated with an inferior polar artery coming directly from the aorta. The patient was placed in the lumbotomy position. An 8-cm midline incision was made above the umbilicus to insert the HandPort system (Smith & Nephew S.A., 72019 Le Mans Cedex2, France). Four additional trocars were introduced. Dissection of the renal artery was carried out beyond the level of relieving the aneurysm behind the vena cava. The main and polar arteries were clipped, and the renal vein was stapled. The kidney was removed through the HandPort and perfused cold ex vivo. The warm ischemia time for the kidney was 1 min, and the total operative time was 280 min. Vascular abnomalies were corrected ex vivo. The postoperative course of the donor was uneventful. At 6 months after transplantation, the graft function was normal. The hand-assisted approach is of particular value on the right side where the dissection must be carried out behind the vena cava. The HandPort may save few precious minutes over the sac extraction technique of the standard laparoscopic procedure.

Primary percutaneous approach to upper urinary tract transitional cell carcinoma.

The optimal approach to upper tract TCC remains to be redefined. A routine nephroureterectomy for every filling defect in the upper urinary system, even in the case of a normal contralateral kidney, constitutes an unnecessary mutilation in more than two thirds of the cases. Nephroureterectomy does not reduce the need for a long-term cystoscopic follow-up because of the high rate of bladder tumor recurrence that may happen years later after nephroureterectomy. Relying solely on radiography and cytology, lacking sensitivity and specificity, to recommend a nephroureterectomy is against the principles of oncologic surgery, especially now that preoperative histologic proof is easy to obtain endoscopically without compromising cancer control. Ureteroscopy, rigid and flexible, provides a complete assessment of the upper urinary system. Biopsy specimens taken with ureteroscopy may be sufficient for grading but less adequate for staging of the tumor. The authors reserve ureteroscopy for ureteral tumors and small (< 1.5 cm) single tumors of the renal pelvis. They approach large or multiple tumors of the renal pelvis percutaneously, in which a full histologic assessment is possible along with a complete resection of the tumor. The decision on the therapeutic approach is made only after the final pathologic report is reviewed. Grade I and grade II superficial disease (Ta, T1) can be treated endoscopically with minimal morbidity and with an efficiency comparable with the standard more invasive nephroureterectomy (Table 5). The indications for endourologic treatment in these cases can be extended safely beyond a solitary kidney or a high surgical risk to include any healthy individual with a normal contralateral kidney who is willing to commit to a rigorous lifelong follow-up. Patients with grade II T1 lesions require a more vigilant follow-up. For grade III Ta disease, more caution should be exercised in selecting these patients for elective endourologic management. When criteria of good prognosis are found, such as absence of carcinoma in situ, presence of diploidy, low p53 expression and a single-tumor, endoscopic management can be offered [table: see text] with a closer follow-up and resorting always to immediate nephroureterectomy at the first evidence of upstaging. Because of the high incidence of recurrence and progression, elective endourologic management for grade III T1 tumors is not recommended. Endoscopic conservative surgery still can be offered in the cases of a solitary kidney or chronic renal insufficiency or for poor surgical candidates. Patients with localized stages (T2, T3) TCC should be offered immediate nephroureterectomy. The authors do not expect adequate endoscopic extirpation with muscle invasive tumors. Although the tissue removed may include deep layers, deep resection is precluded by the thin renal pelvic wall and the associated risk for perforation. Patients with more extensive disease (T3, T4) have a bad prognosis regardless of the form of therapy. Achieving local control percutaneously while preserving as many nephrons as possible for the future chemotherapy can be a reasonable option.

Necrotizing fasciitis in children in eastern Ontario: a case-control study.

BACKGROUND: Early recognition and treatment are important factors that can help improve survival following necrotizing fasciitis. However, early recognition is complicated by the difficulty in distinguishing the infection from other, less serious soft-tissue infections such as cellulitis. We reviewed the charts of children presenting with necrotizing fasciitis at a tertiary care pediatric hospital in Ontario to document potential increases in the frequency of cases and to identify clinical and laboratory features that could help distinguish between necrotizing fasciitis and cellulitis. METHODS: Necrotizing fasciitis was defined as a soft-tissue infection characterized by necrosis of subcutaneous tissue and confirmed at surgery or on pathological examination. A retrospective chart review was conducted to identify cases of necrotizing fasciitis that occurred between June 1, 1983, and May 31, 1999. The characteristics of the identified cases, their clinical manifestations and the laboratory features at presentation were compared with those of matched controls admitted to the hospital with cellulitis. RESULTS: In total, 8 cases of necrotizing fasciitis were identified during the study period. There were no cases from 1983 to 1987, 1 from 1988 to 1991, 1 from 1992 to 1995, and 6 cases from 1996 to 1999. Compared with the children who had cellulitis, those who had necrotizing fasciitis were more likely to present with a generalized erythematous rash (odds ratio [OR] 11.0; 95% confidence interval [CI] 1.5-81.6) and a toxic appearance (OR 23.0; 95% CI 2.0-262.5). They were also more likely than the children with cellulitis to have a history of fever (8/8 v. 10/24, p = 0.004), a higher temperature (mean 38.7 degrees C v. 37.8 degrees C, p = 0.006), a higher respiratory rate (mean 31.5 v. 25.4 breaths/min, p = 0.02) and a lower platelet count on presentation (mean 194.0 v. 299.3 x 10(9)/L, p = 0.03). INTERPRETATION: On presentation, factors that may help distinguish necrotizing fasciitis from cellulitis include a generalized erythematous rash, toxic appearance, fever and low platelet count.

Percutaneous management of grade II upper urinary tract transitional cell carcinoma: the long-term outcome.

PURPOSE: We report the long-term outcome of our experience with percutaneous treatment of grade II upper urinary tract transitional cell carcinoma. MATERIALS AND METHODS: A total of 61 patients with transitional cell carcinoma of the upper urinary tract were treated percutaneously between 1984 and 1998. Of the patients 24 (39%) had grade II disease. Immediate nephroureterectomy was performed due to muscle invasive disease in 2 patients, bleeding in 1 and inability to resect the whole tumor in 1. Percutaneous resection was the actual treatment in 15 patients with stage Ta and 5 with stage T1 disease. RESULTS: Recurrence was noted in 5 patients (25%), including 3 (20%) with stage Ta tumors and 2 (40%) with stage T1 disease after a median followup of 48 months (range 9 months to 12 years). All stage Ta disease recurrences were superficial. In 1 patient with a stage T1 tumor invasive and metastatic disease developed. Disease specific survival was 95% overall, and 100% for stage Ta and 80% for stage T1 disease. No tumor seeding was detected along the percutaneous tract. CONCLUSIONS: Percutaneous surgery has proved safe and effective in treating superficial grade II upper tract transitional cell carcinoma. Offering an endoscopic approach electively to healthy individuals with a normal contralateral kidney seems viable.

Acute ureteral elongation in two animal models using a balloon expander.

BACKGROUND AND OBJECTIVE: Repair of ureteral injuries and strictures often necessitates a major reconstructive procedure such as a psoas hitch, Boari flap, renal mobilization, ileal interposition, or autotransplantation. Tissue expanders have been used to elongate nerves and arteries. We examined the effects of acute ureteral elongation in two animal models. MATERIALS AND METHODS: In eight female rabbits, we exposed the left ureter through a midline incision and placed a Ruiz-Cohen balloon beneath the undermined portion. The expander was then inflated until the ureter was tightly stretched across it. After deflation, the expanded segment was measured in situ and compared with its original length. Follow-up urography was performed, and the tissue was harvested and examined by a pathologist. The same procedure was performed in five pigs; however, in these animals, a segment of ureter was excised, and a ureteroureterostomy was performed, after the acute expansion. RESULTS: We were able to achieve acute elongation of the expanded ureteral segment. The mean elongation was 31.3% in the rabbits and 32.0% in the pigs. An intravenous urogram (IVU) 6 weeks after the elongation showed a functioning kidney and a patent ureter. Histologic examination of the ureter within 24 hours after the expansion revealed that all segments were viable, the luminal epithelium was intact, and the muscular layers appeared normal. At 6 weeks, the expanded segment showed mild inflammatory changes, but the overall morphology, size, and cytology findings were similar to those of a normal control. CONCLUSIONS: Acute ureteral elongation using a tissue expander is a new method of increasing ureteral length. It may be useful to cover defects that would need major operations with greater morbidity.

13-year survival comparison of percutaneous and open nephroureterectomy approaches for management of transitional cell carcinoma of renal collecting system: equivalent outcomes.

BACKGROUND AND OBJECTIVE: Transitional cell carcinoma (TCC) of the renal collecting system traditionally has been managed by open nephroureterectomy with en bloc resection of a bladder cuff. However, for a select patient population with a solitary kidney or bilateral disease, the morbidity and mortality associated with chronic renal insufficiency and dialysis is deterring. In these situations, a more conservative approach such as antegrade percutaneous resection should be considered. The long-term disease-free outcome of percutaneous management in comparison with open nephroureterectomy has not been previously reported. We evaluated our experience with two surgical approaches to treat upper tract TCC: percutaneous resection and nephroureterectomy/nephrectomy to assess the clinical efficacy of these surgical modalities. PATIENTS AND METHODS: We retrospectively identified 162 patients who had clinically localized TCC of the upper urinary tract. Records were reviewed to identify those with 13-year follow-up (N = 110) in respect to tumor grade, stage, disease-free status, length of cancer-specific survival, and overall survival. Statistical analysis of the results of open nephroureterectomy/nephrectomy (N = 60) and percutaneous resection (N = 50) was performed using Kaplan-Meier survival curves and Student's t-test. RESULTS: All patients had disease in clinical stage Ta through T3. During a mean follow-up of 46.6 (range 6-150) months, grade 1 disease demonstrated little invasive potential. Of the disease-specific deaths, 60% (17/26) were of patients with grade 3 lesions, with a mean cancer survival period of 15.2 months after the initial procedure. Disease-specific survival rates after open and percutaneous approaches for grade 2 disease were 53.8 and 53.3 months, respectively (P > 0.05). CONCLUSIONS: Tumor grade appeared to be the most important prognostic indicator in patients with renal TCC regardless of the surgical approach. Grade 3 tumors were more aggressive, presenting in an advanced stage with invasion, and recurrences were usually associated with metastasis. In this population, nephroureterectomy is warranted if the patient is a surgical candidate. The percutaneous option for grade 1 or 2 disease may be extended beyond the population with solitary kidneys and a risk of chronic renal failure to be offered to healthy individuals with normal contralateral kidneys who are willing to abide by a strict and lengthy follow-up.