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We investigate the existence of a global classical solution to the Goursat problem for linearly degenerate quasilinear hyperbolic systems. As the result in [A. Bressan, Contractive metrics for nonlinear hyperbolic systems, Indiana Univ. Math. J. 37 (1988) 409-421] suggests that one may achieve global smoothness even if the C1 norm of the initial data is large, we prove that, if the C1 norm of the boundary data is bounded but possibly large, and the BV norm of the boundary data is sufficiently small, then the solution remains C1 globally in time. Applications include the equation of time-like extremal surfaces in Minkowski space R1 + (1 + n) and the one-dimensional Chaplygin gas equations. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This work is a continuation of our previous work (Shao, Nonlinear Anal. Real World Appl. 11 (2010) 3791–3808) ‘Global structure stability of Riemann solutions for linearly degenerate hyperbolic conservation laws under small BV perturbations of the initial data’. In the present paper, we prove the global structure instability of the Lax's Riemann solution u=U(x/t) containing only shocks and contact discontinuities, and at least a shock wave, of general n×n quasilinear hyperbolic systems of conservation laws under small BV perturbations of the Riemann initial data. The perturbations are in BV but they are assumed to be C1 smooth, with bounded and possibly large C1 norms. We prove the non-existence of global piecewise C1 solution to a class of the generalized Riemann problem, which can be regarded as a small BV perturbation of the corresponding Riemann problem, for general n×n quasilinear hyperbolic systems of conservation laws. Some applications to quasilinear hyperbolic systems of conservation laws arising in physics, particularly to one-dimensional Euler equations of gas dynamics for a compressible, inviscid, non-heat conducting gas in Eulerian coordinates, are also given. [ABSTRACT FROM AUTHOR]

Objective.The aim of this study was to report the authors' experience with percutaneous intrarenal marsupialization of symptomatic peripelvic renal cysts. Material and methods. Thirty-one patients (16 male and 15 female, with a mean age of 49 years) with a peripelvic renal cyst associated with chronic flank or lumbar pain or urinary infection were selected for percutaneous intrarenal marsupialization with a 2 μm laser in the authors' centre from January 2005 to December 2010. Cyst size ranged from 4.5 to 10.5 (mean 6.0) cm. The cysts were punctured by a percutaneous technique guided by ultrasonography, a 20.8 F nephroscope was introduced and the whole internal surface of the cyst was inspected. Methylene blue was injected through the ureteral catheter to help identify the collecting system. A 1.5-4 cm incision was made at the avascular area of the cystic wall by the 2 μm laser to achieve intrarenal marsupialization of the cyst into the renal collecting system. One or two 6 F double-J stents were placed with the proximal end in the cyst for 2-3 months. Results.The mean operation time was 50 (25-120) min. No serious complications such as massive bleeding, urine leak or infected haematoma occurred. The patients were followed up for a mean of 12 (range 3-36) months. All patients were relieved of their symptoms. Eighteen cysts disappeared after surgery, while 13 cysts reduced in size by over one-third and communicated with the renal collecting system. No enlargement of cysts was observed. Conclusions.Percutaneous intrarenal marsupialization with a 2 μm laser is an effective and safe procedure and may offer a minimally invasive alternative for the management of symptomatic peripelvic renal cysts. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the asymptotic behavior of global classical solutions to the mixed initial-boundary value problem with large bounded total variation (BV) data for linearly degenerate quasilinear hyperbolic systems of diagonal form with general non-linear boundary conditions in the half space {(t, x)|t≥0, x≥0}. Based on the existence result on the global classical solution, we prove that when t tends to the infinity, the solution approaches a combination of C1 travelling wave solutions, provided that the C1 norm and the BV norm of the initial and boundary data are bounded but possibly large. Applications include the 1D Born–Infeld system arising in the string theory and high energy physics. [ABSTRACT FROM AUTHOR]

Objective: To explore the surgical approaches, efficacy and safety of percutaneous nephroscopic 2 µm laser incision and drainage in the treatment of peripelvic renal cysts., Methods: The peripelvic renal cysts were punctured percutaneously. A 1.5 - 4.0 cm incision was made at thin avascular area between cyst and pelvis by the 2 µm laser to connect the cyst with the renal collecting system with the help of injecting methylene blue solution into renal pelvis through ureteral catheter. The double-J tube was placed for drainage., Results: The operations were successful in all cases. There were 16 males and 15 females with a mean age of 49 years old. The operative durations ranged from 25 to 120 minutes. And no severe complications occurred. The patients were followed up for an average of 12 months (range: 3 - 36). Among them, cysts disappeared in 18 cases and diminished over 1/3 in 13 cases. There was no recurrence of peripelvic renal cyst., Conclusion: Percutaneous nephroscopic 2 µm laser incision and drainage for peripelvic renal cyst is safe, effective and mini-invasive.

Objective: To evaluate the clinical efficacy of extracorporeal shockwave lithotripsy (ESWL) for bilateral ureteral stones with renal colic in emergency., Methods: We retrospectively analyzed the clinical data of 86 patients suffered with sudden renal colic due to bilateral ureteral stones and treated with ESWL between January 2005 and January 2009., Results: The success rate was 74.4% after a single ESWL session, and the overall success rate was 82.6%. Significant difference in stone length was observed between successful group and failed group (P<0.01). The stone position did not produce significant impact on the outcome of the treatment (P>0.05)., Conclusion: ESWL is an effective treatment modality in emergency for small-length and short-term obstruction bilateral ureteral stones with remal colic.

Objective: To compare the therapeutic effect of 3 minimally invasive approaches for ureteral calculi removal and analyze their respective advantages and limitations., Methods: A retrospective analysis was conducted in 326 patients receiving extracorporeal shock wave lithotripsy (ESWL), ureteroscopic lithotripsy (URL) or percutaneous nephrolithotripsy (PCNL) for ureteral calculi. The clinical data including the stone-free rate and complications were analyzed., Results: The stone free rate was 78.5% (146/186), 91.2 (93/102) and 100% (38/38) in the 3 groups, respectively. According to the stone size, the ESWL group were divided into 3 groups with stone sizes of 0.5-1.0 cm, 1.0-2.0 cm and beyond 2.0 cm, and the stone-free rates were 90.8% (89/98), 69.3% (52/75), and 30.8% (5/13), respectively, showing significant difference between them (P<0.01). In URL group, surgical failure occurred in 9 cases, including 3 cases with difficult entry of the ureter, 5 with stone displacement to the kidneys, and 1 with residual stones over 4 mm. In PCNL group, the percutaneous renal access was successfully established and immediate phase I lithotripsy was performed in all the patients without severe complications recorded during nephrolithotripsy., Conclusion: ESWL is the best option for cases with stone smaller than 10 mm. URL suits most of ureteral calculus cases, but successful entrance of the ureteroscope is a prerequisite and retrograde stone displacement is the primary reason for surgical failure. PCNL is effective in the management of complex upper ureteral stones, especially in cases of failed ESWL or ureteroscopy.

Objective: To evaluate the factors affecting the efficacy of extracorporeal shock wave lithotripsy (ESWL) for renal calculi., Methods: Between January, 2004 and January, 2007, 316 patients (212 men and 104 women) with renal stone underwent ESWL. The correlations of the patients' age, gender, body mass index (BMI), disease course, pain, hematuria, stone size, location, side, number and hydronephrosis to the outcome of the treatment was analyzed. The treatment success was defined as complete clearance of the stones or residual stone fragments <0.4 cm, and ESWL was considered unsuccessful with residual stones>0.4 cm., Results: The overall success rate was 75.3% (238/316) in these patients. Significant difference in stone clearance rates was observed in patients with stone size of 0.5-1.0 cm (90.3%, 167/185), 1.0-2.0 cma(69.6%, 55/79), and >2.0 cm (30.8%, 16/52) (P<0.05). The success rates differed significantly between cases of pelvic stones (83.1%, 118/142) and those of caliceal stones (69.0%, 120/174) (P<0.05). But in cases of caliceal stones, the success rates were comparable between cases with stones at the upper calyx (71.7%, 43/60), middle calyx (68.9%, 31/45), and lower calix (66.7%, 46/69) (P>0.05). Patients with single stones had significantly higher success rate (82.9%,170/205) than those with multiple stones (61.3%, 68/111) (P<0.05). The patients' gender, age, disease course, pain, hematuria, stone side and hydronephrosis did not produce significant impact on the outcome of the treatment (P>0.05)., Conclusion: Stone size, location and quantity are significant independent factors affecting the outcome of ESWL for renal stones.

Objective: To investigate the factors affecting the efficacy of extracorporeal shockwave lithotripsy (ESWL) for upper urinary tract stones., Methods: Between January 2003 and January 2006, 366 patients with upper urinary tract stone underwent ESWL, and the results were identified by regular KUB/IVU or ultrasonography and evaluated 3 months after the treatment. The treatment success was defined as complete clearance of the stones without residual fragments. The stone-free rate was analyzed in relation to the stone features and the patients' clinical characteristics, and the factors identified to significant affect the results were further analyzed using multivariate regression analysis., Results: Three months after the treatment, the overall stone-free (success) rate was 63.4% (232/366) in these patients. Chi square test and t test identified the disease course, stone length and width as the factors with significant impact on the stone-free rate. Multivariate analysis excluded the disease course and stone width from the logistic regression model, and identified the stone length as the independent factor affecting the outcome of ESWL., Conclusion: The stone length is an independent factor influencing the efficacy of ESWL for upper urinary tract stones.

Objective: To explore the expression of hypoxia inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in renal cell carcinoma (RCC) and their relationship., Methods: The expression of HIF-1alphaand VEGF was examined in 42 patients with renal cell carcinoma by SABC methods of immunohistochemistry., Results: The positivity rate of HIF-1alpha was 57.1% in the RCC tissues, and there was no expression in the tissue adjacent to the tumor and normal tissues. The positivity rate of VEGF was 61.9% in the tumor tissues, with significant difference from the control tissues (P<0.05). The expression levels of HIF-1alpha and VEGF were significantly higher in metastatic RCC than in non-metastatic RCC (P<0.01) tissues, and there was a significant correlation between HIF-1alpha and VEGF expressions (Kappa=0.41, P<0.01)., Conclusions: HIF-1alpha is highly expressed in renal cell carcinoma tissues in close correlation with VEGF. HIF-1alpha and VEGF may serve as important indicators to evaluate the biological behaviors of RCC such as metastasis and prognosis. HIF-1alpha is an important regulator of VEGF.

Objective: To evaluate the clinical effects of nephron-sparing surgery in patients with early-stage small renal cell carcinoma., Methods: Nephron-sparing surgery was performed in 21 patients with renal cell carcinoma including 1 with solitary kidney, 3 with unilateral tumor and contralateral renal compromise, and 17 with unilateral tumor and normal contralateral kidney. The diameter of the tumors ranged from 1.5 to 6.0 cm, with a mean of 2.8 cm. The tumor diameter in 17 patients with normal contralateral kidney was less than 4 cm (mean 2.5 cm) and the average diameter in 4 patients with contralateral renal compromise was 4.2 cm. Sixteen cases were in stage T(1), 4 in stage T(2), and 1 in stage T(3). Of the 21 patients, 4 underwent tumor enucleation, 10 polar nephrectomy and 7 wedge resection., Results: All patients were followed up for an average of 40.8 months (7 to 66 months). One patient suffered a right lung and mediastinum metastasis 3 years after the surgery later and 1 with chronic glomerulonephritis required dialysis 27 months after the operation. No surgical complication or local recurrence were found in other patients., Conclusion: As a safe and effective therapy for early-stage small renal cell carcinoma, nephron-sparing surgery can be considered as the gold-standard therapy for patients with lesions less than 4 cm in T(1) and T(2) stages of localized unilateral tumor with normal contralateral kidney.