Low-pressure Pneumoperitoneum With Abdominal Wall Lifting Versus Standard Pressure Pneumoperitoneum in Laparoscopic Fundoplication for Gastroesophageal Reflux Disease: A Propensity Score-matched Analysis.

OBJECTIVE: The objective of this study was to compare the treatment results of low-pressure pneumoperitoneum with abdominal wall lifting (AWL+LP, 6 mm Hg) versus standard pressure pneumoperitoneum (SP, 12 mm Hg) during laparoscopic fundoplication for gastroesophageal reflux disease (GERD), using propensity score matching (PSM). MATERIALS AND METHODS: A retrospective analysis was made of 362 patients, 123 in the AWL+LP group and 239 in the SP group, who underwent laparoscopic fundoplication for GERD from January 2010 to December 2017. Perioperative and prognostic outcomes were compared after PSM with 1:1 match. RESULTS: After PSM, 107 matched pairs were obtained. Compared with the SP group at 30 and 60 minutes after pneumoperitoneal initiation, the AWL+LP group showed significantly lower end-tidal carbon dioxide value (P<0.001, <0.001, respectively), lower partial pressure of carbon dioxide value (P<0.001, 0.016, respectively) and significantly higher pH value (P<0.001, <0.001, respectively). However, postoperative shoulder pain, abdominal pain, and arrhythmia in the AWL+LP group were less than those in SP group (P=0.01, 0.017, 0.005, respectively). There was no significant difference in operative time (106.54±27.80 vs. 107.38±24.78 min), blood loss [15 mL (interquartile range: 12.5 to 20 mL) vs.15 mL (interquartile range: 10 to 20 mL)], length of stay (4 vs. 4 d), the wound ecchymosis [2 (1.87%) vs. 3 (2.80%)] and rates of recurrence [8 (7.48%) vs. 5 (4.67%)] between AWL+LP group and SP group. CONCLUSION: AWL+LP resulted in comparable perioperative and prognostic outcomes with less impact on changes in cardiorespiratory function compared with SP approaches of laparoscopic fundoplication for GERD.

Case Report: MDM4 Amplified in a Thymoma Patient With Autoimmune Enteropathy and Myocarditis.

Introduction: Thymoma is a type of mediastinal malignant tumors which always associated with autoimmune diseases. Although surgery is the predominant treatment method for thymoma, the pathogenesis of thymoma and thymoma-associated autoimmune diseases is still unknown. However, the case study here provided a possible pathogenesis and treatment to cure the thymoma with autoimmune enteropathy and myocarditis. Case presentation: A thymoma case with autoimmune enteropathy and myocarditis undergoing surgery was reported. The symptoms and laboratory results of the patient had dramatically fluctuated after tumor resection and gradually alleviated. The whole exome sequencing found MDM4 amplified in tumor cells. Immunohistochemistry indicated that thymoma cells were positive for MDM4. The result of drug sensitivity tests showed thymoma cells were highly sensitive to Nutlin-3a. Conclusion: MDM4 could play an important role in the pathogenesis of this thymoma case with autoimmune enteropathy and myocarditis. This discovery may provide a novel idea of pathogenesis and treatment for thymoma and autoimmune diseases.

Placing covered self-expanding metal stents by suspension laryngoscope in benign tracheal stenosis.

BACKGROUND: Tracheobronchial stent placement for malignant airway strictures has been proved to improve respiratory function, but experience for benign tracheobronchial stenoses is limited. The purpose of our study is to investigate the efficacy of covered expandable metallic stents, inserted through a suspension laryngoscope, treating tracheal stenosis following intubation or tracheostomy. METHODS: From 2010 to 2018, 67 adult patients with the benign tracheal stenosis, underwent stent placement, using a suspension laryngoscope. According to the date of stent placement and stent caliber, these patients have been subdivided into two groups: Group 1 (from 2010 to 2013, stent caliber ranging from 16 to 20 mm) and Group 2 (from 2014 to 2018, stent caliber ranging from 18 to 22 mm). Complications, related reinterventions, and long-term prognosis were retrospectively evaluated. RESULTS: Primary successful stent placement was achieved and symptoms were improved in all patients. Complications occurred in 27 (40.3%) cases. Among these, there were 14 (20.9%) cases with stent migration, 10 (14.93%) with granulation tissue formation and 3 (4.48%) with pneumonia. Stent migration in Group 1 was nearly 30% higher than that in Group 2 (P = 0.002). Five of the 8 patients who had placement of 16 mm stents had stent migration, more often than with 20 mm stents (P = 0.002). Ten patients' trachea had slight narrowing but without any symptoms. Six patients still had granulation tissue but without any growth at least two-year follow-up (2 patients whose stents were removed more than 1 year after placement). Even without tracheal narrowing and granulation tissue, 5 patients felt persistent shortness of breath. 92.5% of the patients reported to be satisfied with significant improvement in symptoms. CONCLUSIONS: Patients with tracheal obstruction secondary to intubation or tracheostomy can benefit from tracheal stents. Placing 16 mm stents might lead to stent migration more easily than 20 mm stents. Tracheal stents placed by a suspension laryngoscope provide a reasonable alternative to open surgery for patients with benign tracheal stenosis or obstruction.

Surgical feasibility and long-term outcome of superior vena cava replacement for advanced thymoma in patients undergoing preoperative chemotherapy or chemoradiotherapy.

BACKGROUND: The aim of this study was to investigate the long-term outcome of superior vena cava (SVC) replacement after chemotherapy or chemoradiotherapy for advanced thymoma. METHODS: The medical information of patients with advanced thymoma who underwent thymoma resection and SVC replacement in Beijing Tongren Hospital from 2002 to 2017 were reviewed. We compared surgical outcomes, postoperative complications and long-term prognosis in the chemoradiotherapy + surgery group (CRT + surgery group, 19 cases) and the surgery group (26 cases). RESULTS: The operation time (486.05 ± 148.01 vs. 370.77 ± 124.32 min; p = 0.007) and intraoperative blood loss (1400 ml [IQR 1125-2105 ml] vs. 855 ml [IQR 555-1682.5 ml], p = 0.036), poor wound healing (three cases [15.79%] vs. zero cases [0.0%], p = 0.036) in the CRT + surgery group were significantly higher than those of the surgery group. There was no significant difference between the CRT + surgery group and the surgery group in postoperative chest tube drainage time, hospitalization time, postoperative arrhythmia and incidence of pneumonia. Kaplan Meier analysis showed that the recurrence-free survival (RFS) curves of the CRT + surgery group patients were better than those of the surgery group (p = 0.031). However, overall survival (OS) between the two groups was not significantly different (p = 0.069). CONCLUSIONS: Thymoma resection and SVC replacement is feasible for patients undergoing preoperative induction chemotherapy or chemoradiotherapy for advanced thymoma. Although patients in the CRT + surgery group had a longer operation time and increased intraoperative bleeding, the RFS rate seemed to be better than that in the surgery group.

Clinical and Genetic Characteristics of Thymoma Patients With Autoimmune Hepatitis and Myocarditis.

BACKGROUND: Our study investigated a special series of thymoma with autoimmune hepatitis and myocarditis and tried to reveal the gene expression profiles of this series of thymoma. METHODS: From 2011 to 2019, a total of 13 special thymoma patients presented with autoimmune hepatitis and myocarditis, accounting for about 1.26% of thymoma patients undergoing surgery in Beijing TongRen Hospital. Clinical data were retrospectively collected. All samples were harvested during surgical procedures, and analyzed to identify changes in gene expression using the CapitalBio mRNA microarray analysis, the Whole exome sequencing analysis (WES), qPCR and immunohistochemistry (IHC) tools. RESULTS: After surgery, patient symptoms were relieved gradually. Levels of lactate dehydrogenase (LDH), creatine kinase MB (CK-MB), aspartate transaminase (AST), and alanine amiotransferase (ALT) increased to some extent within 1 to 3 months after surgery, and fluctuated, and then, gradually decreased close to normal within 6 months after surgery. Enrichment analysis of Kyoto Genome and Genome Encyclopedia (KEGG) pathway was performed and enrichment results were visualized. It indicated that gene expression of 5 signaling pathways, including cell cycle and p53 signaling pathway, were generally abnormal. P53 expression was up-regulated in all tumor tissues. However, IHC and qPCR analysis showed that there was no significant difference in p21 expression between normal and tumor tissue. Results of WES showed that only one driver gene-MDM4 amplified 4 fold in 53.2% thymoma cells. Further qPCR and IHC analysis confirmed the up-regulation of the expression of p53 and mdm4 in 13 thymoma patients with autoimmune hepatitis and myocarditis. CONCLUSION: Our study reveals the clinical and genetic characteristics of thymoma patients with autoimmune hepatitis and myocarditis. For this special category of thymoma, the up-regulation of p53 and mdm4 plays an important role in the occurrence of thymoma and autoimmune hepatitis/myocarditis.

Evaluating the effectiveness of chemotherapy for thymic epithelial tumors using the CD-DST method.

BACKGROUND: Thymic epithelial tumors (TET) are frequently eligible for curative-intent surgical resection. For locally advanced TETs, chemotherapy has been used to both reduce the tumor burden and achieve prolonged disease control. However, effective therapy for this disease largely remains to be determined. Here, we report the chemosensitivity of 100 patients with TETs determined by the collagen gel droplet embedded culture-drug sensitivity test (CD-DST). METHODS: A total of 100 patients with TETs underwent surgical resection. The efficacy of antitumor agents on TET cells was tested by CD-DST. RESULTS: Thymic epithelial tumors were pathologically confirmed after surgery: two cases were type A thymoma, 17 were type AB, 12 were type B1, 44 were type B2, 12 were type B3, and there were 13 cases with thymic carcinoma. A total of 36% patients with TETs were sensitive to different types of chemotherapeutic agents. There was no significant differences in age, histological type, clinical staging, or association with autoimmune diseases between sensitive and nonsensitive cases. Type B1 and B2 thymoma were relatively more sensitive to chemotherapeutic agents (6/12 and 18/44, respectively), while sensitivity of type B3 cases to chemotherapeutic agents was much lower (only 2/12). Cases with type A thymoma were not sensitive to any antitumor drugs. Among 11 chemotherapeutic agents tested in our study, the sensitivity of TETs to EPI was the highest (16%). No patients with thymoma were sensitive to Alimta (Pemetrexed). CONCLUSIONS: Our work illuminates the effectiveness of chemotherapy for TETs and provides important clues for choosing antitumor drugs with relatively high drug sensitivity to TETs in advance.

Temporal and Spatial Evolution of Vegetation Coverage in the Mianyuan River Basin Influenced by Strong Earthquake Disturbance.

The 2008 Wenchuan earthquake caused significant economic losses and degradation of regional ecosystems, including the terrestrial vegetation. Since the vegetation root system can enhance the soil's anti-erosion capacity and therefore mitigate the occurrence of slope instabilities, it is beneficial to study the spatial and temporal evolution of vegetation for a long-term assessment of co-seismic secondary disasters. The Mianyuan River Basin, an uninhabited area passing through an active fault located in the earthquake-affected region, was selected as the study area. The Normal Difference Vegetation Index (NDVI) was calculated using remote sensing images from 1994 to 2017 to analyze the process of vegetation growth, loss, fluctuation and recovery. Statistical results suggest that the area in the middle and lower reaches, near the river network, and with a slope of 30 to 40 degrees were variable regions, showing more significant vegetation destruction during the earthquake and faster repair after the seismic event. Besides, vegetation near the fault was damaged more severely after the earthquake, but the active fault did not play an essential role in the vegetation recovery period. In the Mianyuan River Basin, vegetation experienced a volatility period (5 plus or minus one year) before entering the recovery period. In 8 to 9 years after the earthquake, the surficial vegetation could recover to the state before the earthquake.

The effect of tetrahedron framed permeable weirs on river bed stability in a mountainous area under clear water conditions.

A flexible riverbed protection called tetrahedron framed permeable weirs (TFPW) is proposed to protect riverbeds in mountainous areas from scouring. Under clear water conditions, a series of laboratory flume experiments were performed to study the effects of TFPW with different layout types on the stability of riverbeds. The objectives of this paper were to advance understanding of the role that TFPW play in the erosion process of river beds and to optimize the TFPW design for reducing velocity, promoting sediment deposition and good structural stability. Data on velocity distribution and variation, equilibrium bathymetry, flow resistance, bed form characteristics and structural stability were collected and analyzed. The results indicate that (1) with good structural stability, all the TFPW with different layout types had significant effects on the stabilization of the riverbed by reducing velocity, raising the water level, increasing the roughness coefficient, protecting the riverbed from degradation and promoting deposition; and (2) the random Double TFPW with large rates of deceleration, large deposition ranges, and good structural stability, and the paved Single TFPW with small rates of deceleration but large deposition ranges and perfect structural stability, were suitable and optimal for riverbed protection in a clear water channel.

An analysis of the entrainment effect of dry debris avalanches on loose bed materials.

Substrate entrainment can greatly influence the mass movement process of a debris avalanche because it can enlarge the landslide volume and change the motion characteristics of the sliding masses. To study the interaction between debris avalanches and erodible substrate, physical modeling experiments varying in the mass of granular flow and substrate thickness were performed. The experimental results show that both the entrained materials and the maximum erosion depth are increased with increasing mass of the debris avalanche and decreasing substrate thickness. During the experiment, several tests were recorded using a high-speed digital camera with a frequency of 500 frames per second, so that the process of entrainment could be clearly observed. Combined with the experiment result and results of previous studies from predecessors, the entrainment mechanism during debris avalanches are analyzed and discussed. The entrainment effect of the sliding masses on the loose bed materials include basal abrasion and impact erosion of the avalanche front, the latter of which can contribute to the former by failing or yielding the erodible bed.

Forecasting and prevention of water inrush during the excavation process of a diversion tunnel at the Jinping II Hydropower Station, China.

INTRODUCTION: Estimating groundwater inflow into a tunnel before and during the excavation process is an important task to ensure the safety and schedule during the underground construction process. CASE DESCRIPTION: Here we report a case of the forecasting and prevention of water inrush at the Jinping II Hydropower Station diversion tunnel groups during the excavation process. The diversion tunnel groups are located in mountains and valleys, and with high water pressure head. Three forecasting methods are used to predict the total water inflow of the #2 diversion tunnel. Furthermore, based on the accurate estimation of the water inrush around the tunnel working area, a theoretical method is presented to forecast the water inflow at the working area during the excavation process. DISCUSSION AND EVALUATION: The simulated results show that the total water flow is 1586.9, 1309.4 and 2070.2 m(3)/h using the Qshima method, Kostyakov method and Ochiai method, respectively. The Qshima method is the best one because it most closely matches the monitoring result. According to the huge water inflow into the #2 diversion tunnel, reasonable drainage measures are arranged to prevent the potential disaster of water inrush. The groundwater pressure head can be determined using the water flow velocity from the advancing holes; then, the groundwater pressure head can be used to predict the possible water inflow. The simulated results show that the groundwater pressure head and water inflow re stable and relatively small around the region of the intact rock mass, but there is a sudden change around the fault region with a large water inflow and groundwater pressure head. Different countermeasures are adopted to prevent water inrush disasters during the tunnel excavation process. CONCLUSION: Reasonable forecasting the characteristic parameters of water inrush is very useful for the formation of prevention and mitigation schemes during the tunnel excavation process.

Experimental research on the dam-break mechanisms of the Jiadanwan landslide dam triggered by the Wenchuan earthquake in China.

Dam breaks of landslide dams are always accompanied by large numbers of casualties, a large loss of property, and negative influences on the downstream ecology and environment. This study uses the Jiadanwan landslide dam, created by the Wenchuan earthquake, as a case study example. Several laboratory experiments are carried out to analyse the dam-break mechanism of the landslide dam. The different factors that impact the dam-break process include upstream flow, the boulder effect, dam size, and channel discharge. The development of the discharge channel and the failure of the landslide dam are monitored by digital video and still cameras. Experimental results show that the upstream inflow and the dam size are the main factors that impact the dam-break process. An excavated discharge channel, especially a trapezoidal discharge channel, has a positive effect on reducing peak flow. The depth of the discharge channel also has a significant impact on the dam-break process. The experimental results are significant for landslide dam management and flood disaster prevention and mitigation.