Is the Supine Position Suitable for Ultrasound-Guided Percutaneous Nephrolithotomy in Patients with Complex Renal Stones?

INTRODUCTION: The aim of the study was to assess the safety and efficacy of ultrasound (US)-guided percutaneous nephrolithotomy (PCNL) for complex renal stones when performed in a modified supine position. METHODS: We retrospectively reviewed the charts of patients who underwent PCNL for complex renal stones at our institution between August 2018 and December 2021. During this time, 188 consecutive patients underwent US-guided PCNL in the prone position (P group, n = 129) or in the flank-free modified supine position (S group, n = 59). Patient demographics and intraoperative and postoperative data were analyzed. RESULTS: Successful renal access was achieved in all patients. The baseline demographics were comparable between the two groups. The numbers of renal access were significantly higher (2.1 ± 0.4 vs. 1.2 ± 0.2, p = 0.002), and the operation time was comparable (79.1 ± 14.6 min vs. 96.2 ± 19.6 min, p = 0.06) between the two groups. The postoperative hospital stay was also shorter in the P group (6.2 ± 1.5 d vs. 10.2 ± 1.7 d, p = 0.008). The postoperative hemoglobin loss was similar between the P and S groups (1.7 ± 0.4 g/dL vs. 1.8 ± 0.3 g/dL, p = 0.12). The stone-free rate was significantly lower in the S group (57.5% vs. 82.7%, p < 0.001). There were no embolization or septic complications. Twelve patients (20.3%) in the S group underwent simultaneous or staged retrograde flexible ureteroscopy to remove residual stones. CONCLUSION: US-guided PCNL in the modified supine position was a safe treatment for complex renal stones. However, the single-session stone clearance rate was not ideal. The supine flank-free position may be unsuitable for US-guided PCNL in patients with complex renal stones according to our preliminary findings.

Effects of Atomic Ratio on the Mechanical Properties of Amorphous Silicon Carbon Nitride.

This paper evaluates the mechanical properties of amorphous silicon carbon nitride (a-SiCxNy) films with different atomic ratios via molecular dynamics simulation. The Si-C-N ternary amorphous model is constructed using ReaxFF potential and melt-quenching method. The results demonstrate that the density range of constructed model spans a wide range of densities (2.247-2.831 g/cm3). The short- and medium-range order of the constructed a-SiCxNy structures show a good correlation with the experimental observations. Based on the structural feasibility, the elastoplastic performance is analyzed. There is significant ductility during the uniaxial tension process of a-SiCxNy, except for Si(CN2)2. The calculated elastic modulus ranges from 206.80 GPa to 393.58 GPa, close to the experimental values of coating films. In addition, the elastic modulus of a-SiCxNy does not change monotonically with the carbon or silicon content but is related to the atomic ratio. This article provides an understanding of the chemical composition dependence of the mechanical properties of amorphous compounds at the molecular level.

Control of the Longitudinal Compression and Transverse Focus of Ultrafast Electron Beam for Detecting the Transient Evolution of Materials.

Ultrafast detection is an effective method to reveal the transient evolution mechanism of materials. Compared with ultra-fast X-ray diffraction (XRD), the ultra-fast electron beam is increasingly adopted because the larger scattering cross-section is less harmful to the sample. The keV single-shot ultra-fast electron imaging system has been widely used with its compact structure and easy integration. To achieve both the single pulse imaging and the ultra-high temporal resolution, magnetic lenses are typically used for transverse focus to increase signal strength, while radio frequency (RF) cavities are generally utilized for longitudinal compression to improve temporal resolution. However, the detection signal is relatively weak due to the Coulomb force between electrons. Moreover, the effect of RF compression on the transverse focus is usually ignored. We established a particle tracking model to simulate the electron pulse propagation based on the 1-D fluid equation and the 2-D mean-field equation. Under considering the relativity effect and Coulomb force, the impact of RF compression on the transverse focus was studied by solving the fifth-order Rung-Kutta equation. The results show that the RF cavity is not only a key component of longitudinal compression but also affects the transverse focusing. While the effect of transverse focus on longitudinal duration is negligible. By adjusting the position and compression strength of the RF cavity, the beam spot radius can be reduced from 100 µm to 30 µm under the simulation conditions in this paper. When the number of single pulse electrons remains constant, the electrons density incident on the sample could be increased from 3.18×1012 m-2 to 3.54×1013 m-2, which is 11 times the original. The larger the electron density incident on the sample, the greater the signal intensity, which is more conducive to detecting the transient evolution of the material.

Multiphoton Absorption Simulation of Sapphire Substrate under the Action of Femtosecond Laser for Larger Density of Pattern-Related Process Windows.

It is essential to develop pattern-related process windows on substrate surface for reducing the dislocation density of wide bandgap semiconductor film growth. For extremely high instantaneous intensity and excellent photon absorption rate, femtosecond lasers are currently being increasingly adopted. However, the mechanism of the femtosecond laser developing pattern-related process windows on the substrate remains to be further revealed. In this paper, a model is established based on the Fokker-Planck equation and the two-temperature model (TTM) equation to simulate the ablation of a sapphire substrate under the action of a femtosecond laser. The transient nonlinear evolutions such as free electron density, absorption coefficient, and electron-lattice temperature are obtained. This paper focuses on simulating the multiphoton absorption of sapphire under femtosecond lasers of different wavelengths. The results show that within the range of 400 to 1030 nm, when the wavelength is large, the number of multiphoton required for ionization is larger, and wider and shallower ablation pits can be obtained. When the wavelength is smaller, the number of multiphoton is smaller, narrower and deeper ablation pits can be obtained. Under the simulation conditions presented in this paper, the minimum ablation pit depth can reach 0.11 µm and the minimum radius can reach 0.6 µm. In the range of 400 to 1030 nm, selecting a laser with a shorter wavelength can achieve pattern-related process windows with a smaller diameter, which is beneficial to increase the density of pattern-related process windows on the substrate surface. The simulation is consistent with existing theories and experimental results, and further reveals the transient nonlinear mechanism of the femtosecond laser developing the pattern-related process windows on the sapphire substrate.

Outcomes of ultrasound-guided percutaneous nephrolithotomy for the treatment of large stones within non-functioning atrophic kidneys.

OBJECTIVES: To evaluate outcomes in patients who underwent total ultrasound-guided percutaneous nephrolithotomy for the management of large stones (>2 cm) within non-functioning atrophic kidneys, and to identify risk factors associated with postoperative persistence of urinary tract infection symptoms in such patients. METHODS: Between December 2014 and May 2019, 56 patients with large stones within non-functioning atrophic kidneys were treated at Beijing Tsinghua Changgung Hospital, Beijing, China, with total ultrasound-guided percutaneous nephrolithotomy. Factors including age, sex, previous medical history, stone burden, stone composition, stone-free rate, complication rate and postoperative urinary tract infection symptoms were retrospectively evaluated. Uni- and multivariate analyses were carried out to identify risk factors that predict persistence of urinary tract infection symptoms after percutaneous nephrolithotomy in such patients. RESULTS: The final stone-free rate after auxiliary treatments was 87.5%. The overall complication rate was 17.9%. After a median follow-up period of 12 months (range 6-40 months), three patients (5.4%) ultimately underwent nephrectomy. A total of 44 patients (78.6%) had no symptoms of urinary tract infection during follow up, whereas 63.6% of patients with diabetes continued to show persistent urinary tract infection symptoms at the latest follow up. Five patients (8.9%) showed improved total renal function, while most patients (83.9%) showed a stable estimated glomerular filtration rate. Diabetes was the only factor showing statistical significance in both univariate and multivariate analyses that predicted persistence of urinary tract infection symptoms after treatment with percutaneous nephrolithotomy. CONCLUSIONS: Ultrasound-guided percutaneous nephrolithotomy is a safe and feasible procedure that can be carried out in patients with large stones within non-functioning atrophic kidneys. However, for such patients with diabetes, percutaneous nephrolithotomy is not recommended.

Percutaneous Nephrolithotomy Under X-Ray-Free Technique in Upper Urinary Stone Patients with Autosomal Dominant Polycystic Kidney Disease: Experience from a Large-Volume Stone Management Center.

Objectives: To present our large single-center experience in the management of autosomal dominant polycystic kidney disease (ADPKD) with total ultrasound (US)-guided percutaneous nephrolithotomy (PNL) and to evaluate the role of PNL under US in these patients. Patients and Methods: We retrospectively reviewed the charts of patients with ADPKD who underwent PNL from August 2011 to December 2019. A total of 56 patients were included in this study; all procedures were completed by the total US-guided technique. Demographic characteristics, operative parameters, and postoperative data were collected and analyzed. Results: Effective renal access was achieved in all patients. The mean stone size was 3.1 cm (range 1.7-6.5 cm). The initial stone-free rate was 70.6% (36/51); five patients underwent second-look PNL to remove residual stones. The other patients underwent oral medication therapy. No severe intraoperative complications occurred; one patient received selective embolization for bleeding on the contralateral side and one patient needed percutaneous drainage for perinephric abscess. Clavien I or II complications were seen in nine patients. Renal function was improved or stable in most patients; the condition of only one patient deteriorated after surgery. Conclusion: Total US-guided PNL is a safe and efficient treatment for kidney stones in patients with ADPKD; perioperative renal function was not adversely affected and complications were acceptable compared with patients in the general population.

Let-7d inhibits intratumoral macrophage M2 polarization and subsequent tumor angiogenesis by targeting IL-13 and IL-10.

The microRNA let-7d has been reported to be a tumor suppressor in renal cell carcinoma (RCC). Tumor-associated macrophages (TAM) are M2-polarized macrophages that can enhance tumor growth and angiogenesis in many human cancers. However, the role of let-7d in TAM-associated RCC progression remains elusive. First, we observed a strongly inverse correlation between let-7d expression and microvessel density in RCC tissues. Furthermore, the proliferation, migration, and tube formation of HUVECs were significantly inhibited by conditioned medium from a coculture system of the phorbol myristate acetate pretreated human THP-1 macrophages and let-7d-overexpressing RCC cells. Moreover, the proportion of M2 macrophages was significantly lower in the group that was cocultured with let-7d-overexpressing RCC cells. Subcutaneous xenografts formed by the injection of let-7d-overexpressing RCC cells together with THP-1 cells resulted in a significant decrease in the M2 macrophage ratio and microvessel density compared with those formed by the injection of control RCC cells with THP-1 cells. In silico and experimental analysis revealed interleukin-10 (IL-10) and IL-13 as let-7d target genes. Importantly, the addition of IL-10 and IL-13 counteracted the inhibitory effects of the conditioned medium from the coculture system with let-7d-overexpressing RCC cells in vitro. Additionally, overexpression of IL-10 and IL-13 reversed the effects of let-7d on macrophage M2 polarization and tumor angiogenesis in vivo. Finally, the expression of IL-10 and IL-13 were inversely correlated with the expression of let-7d in RCC clinical specimens. These results suggest that let-7d may inhibit intratumoral macrophage M2 polarization and subsequent tumor angiogenesis by targeting IL-10 and IL-13.

A Novel Surgical Technique for Treatment of Renal Stones in Preschool-aged Patients: Initial Experience With Needle-perc.

OBJECTIVE: To describe and evaluate our newly developed minimal instrumentation technique, needle-perc, for treatment of preschool-aged patients with renal stones. To the best of our knowledge, this is the smallest endoscopic equipment for percutaneous nephrolithotomy reported thus far. MATERIALS AND METHODS: Needle-perc was performed in 8 patients using a 4.2-Fr needle to achieve access to the collecting system under ultrasonic guidance alone. The mean patient age was 2.4 years (range, 0-5 years). Five of the 8 patients were boys, while 3 were girls. Six patients had unilateral stones and 2 patients had bilateral stones. Six renal units exhibited single calculus, 2 exhibited staghorn stones, and 2 exhibited multiple stones. The mean calculus size was 1.6 cm (range, 0.8-4.5 cm). Preoperative, intraoperative, and postoperative parameters were analyzed prospectively. RESULTS: Access was successfully achieved in all patients. Puncturing was fully guided by ultrasound. Five patients underwent needle-perc alone. Two patients were transferred to 16-Fr access because of intrarenal infection and large stone burden. One patient underwent reduction of tract number. The mean operative time was 49.2 minutes (range, 22-75 minutes); mean hemoglobin loss was 5.2 g/L (range, 0-13.8 g/L). The mean postoperative hospital stay was 5 days (range, 3-7 days). Preplaced catheters were kept for 2-3 days to facilitate fragment discharge. Complications occurred in 2 patients: fever >38.5°C. The stone-free rate was 100% at 1 month postoperatively. CONCLUSION: Our initial data indicate that needle-perc is feasible and safe for preschool-aged renal patients. Further studies are required to define its usefulness in treatment of larger stones.

MiR-21 promotes calcium oxalate-induced renal tubular cell injury by targeting PPARA.

Kidney stone disease is a crystal concretion formed in the kidneys that has been associated with an increased risk of chronic kidney disease. MicroRNAs are functionally involved in kidney injury. Data mining using a microRNA array database suggested that miR-21 may be associated with calcium oxalate monohydrate (COM)-induced renal tubular cell injury. Here, we confirmed that COM exposure significantly upregulated miR-21 expression, inhibited proliferation, promoted apoptosis, and caused lipid accumulation in an immortalized renal tubular cell line (HK-2). Moreover, inhibition of miR-21 enhanced proliferation and decreased apoptosis and lipid accumulation in HK-2 cells upon COM exposure. In a glyoxylate-induced mouse model of renal calcium oxalate deposition, increased miR-21 expression, lipid accumulation, and kidney injury were also observed. In silico analysis and subsequent experimental validation confirmed the peroxisome proliferator-activated receptor (PPAR)-α gene (PPARA) a key gene in fatty acid oxidation, as a direct miR-21 target. Suppression of miR-21 by miRNA antagomiR or activation of PPAR-α by its selective agonist fenofibrate significantly reduced renal lipid accumulation and protected against renal injury in vivo. In addition, miR-21 was significantly increased in urine samples from patients with calcium oxalate renal stones compared with healthy volunteers. In situ hybridization of biopsy samples from patients with nephrocalcinosis revealed that miR-21 was also significantly upregulated compared with normal kidney tissues from patients with renal cell carcinoma who underwent radical nephrectomy. These results suggested that miR-21 promoted calcium oxalate-induced renal tubular cell injury by targeting PPARA, indicating that miR-21 could be a potential therapeutic target and biomarker for nephrolithiasis.

Analysis of Factors Influencing Mayo Adhesive Probability Score in Partial Nephrectomy.

BACKGROUND To retrospectively explore the factors influencing Mayo Adhesive Probability (MAP) score in the setting of partial nephrectomy. MATERIAL AND METHODS Data of 93 consecutive patients who underwent laparoscopic and open partial nephrectomy from September 2015 to June 2016 were collected and analyzed retrospectively. Preoperative radiological elements were independently assessed by 2 readers. Ordinal logistic regression analyses were performed to evaluate radiological and clinicopathologic influencing factors of MAP score. RESULTS On univariate analysis, MAP score was associated with male sex, older age, higher body mass index (BMI), history of hypertension and diabetes mellitus, and perirenal fat thickness (posterolateral, lateral, anterior, anterolateral, and medial). On multivariate analysis, only posterolateral perirenal fat thickness (odds ratio [OR]=0.88 [0.82-0.95], p=0.001), medial perirenal fat thickness (OR=0.90 [0.83-0.98], p=0.01), and history of diabetes mellitus (OR=5.42 [1.74-16.86], p=0.004) remained statistically significant. Tumor type (malignant vs. benign) was not statistically different. In patients with renal cell carcinoma (RCC), there was no difference in tumor stage or grade. CONCLUSIONS MAP score is significantly correlated with some preoperative factors such as posterolateral and medial perirenal fat thickness and diabetes mellitus. A new radioclinical scoring system including these patient-specific factors may become a better predictive tool than MAP score alone.

Taurine drinking attenuates the burden of intestinal adult worms and muscle larvae in mice with Trichinella spiralis infection.

The parasitic nematode Trichinella spiralis can cause trichinellosis, which leads to pathological processes in the intestine and muscle. The intestinal invasion determines the development, subsequent course, and consequences of the disease. Gastrointestinal nematode infection, including with T. spiralis, is accompanied by a rapid and reversible expansion of mucosal mast cell and goblet cell in the intestinal epithelium, which play important roles in the host immune response to parasite and worm expulsion from the intestine. Taurine and its derivatives have anti-infection and anti-inflammatory properties. We investigated whether taurine supplementation in mice could influence the development and pathological processes of infection with T. spiralis. Supplementing 1% taurine in drinking water in mice infected with T. spiralis could alleviate the burden of intestinal adult worms on days 7 and 10 postinfection (all p < 0.01) and the formation of infective muscle larvae in striated muscle during T. spiralis infection (p < 0.01). As compared with T. spiralis infection alone, taurine treatment increased the number of goblet cells on days 7, 10, and 15 (p < 0.01 and p < 0.05) and alleviated intestinal mucosal mast cell hyperplasia on days 10 and 15 (all p < 0.01). So taurine supplementation in drinking water increased infection-induced intestinal goblet cell hyperplasia and ameliorated mucosal mastocytosis. Thus, taurine can ameliorate the pathological processes of trichinellosis and may be of great value for the treatment and prevention of infection with T. spiralis and other gastrointestinal nematodes.