[Development and validation of a prognostic prediction model for patients with stage Ⅰ to Ⅲ colon cancer incorporating high-risk pathological features]

Objective: To examine a predictive model that incorporating high risk pathological factors for the prognosis of stage Ⅰ to Ⅲ colon cancer. Methods: This study retrospectively collected clinicopathological information and survival outcomes of stage Ⅰ~Ⅲ colon cancer patients who underwent curative surgery in 7 tertiary hospitals in China from January 1, 2016 to December 31, 2017. A total of 1 650 patients were enrolled, aged (M(IQR)) 62 (18) years (range: 14 to 100). There were 963 males and 687 females. The median follow-up period was 51 months. The Cox proportional hazardous regression model was utilized to select high-risk pathological factors, establish the nomogram and scoring system. The Bootstrap resampling method was utilized for internal validation of the model, the concordance index (C-index) was used to assess discrimination and calibration curves were presented to assess model calibration. The Kaplan-Meier method was used to plot survival curves after risk grouping, and Cox regression was used to compare disease-free survival between subgroups. Results: Age (HR=1.020, 95%CI: 1.008 to 1.033, P=0.001), T stage (T3:HR=1.995,95%CI:1.062 to 3.750,P=0.032;T4:HR=4.196, 95%CI: 2.188 to 8.045, P<0.01), N stage (N1: HR=1.834, 95%CI: 1.307 to 2.574, P<0.01; N2: HR=3.970, 95%CI: 2.724 to 5.787, P<0.01) and number of lymph nodes examined (≥36: HR=0.438, 95%CI: 0.242 to 0.790, P=0.006) were independently associated with disease-free survival. The C-index of the scoring model (model 1) based on age, T stage, N stage, and dichotomous variables of the lymph nodes examined (<12 and ≥12) was 0.723, and the C-index of the scoring model (model 2) based on age, T stage, N stage, and multi-categorical variables of the lymph nodes examined (<12, 12 to <24, 24 to <36, and ≥36) was 0.726. A scoring system was established based on age, T stage, N stage, and multi-categorical variables of lymph nodes examined, the 3-year DFS of the low-risk (≤1), middle-risk (2 to 4) and high-risk (≥5) group were 96.3% (n=711), 89.0% (n=626) and 71.4% (n=313), respectively. Statistically significant difference was observed among groups (P<0.01). Conclusions: The number of lymph nodes examined was an independent prognostic factor for disease-free survival after curative surgery in patients with stage Ⅰ to Ⅲ colon cancer. Incorporating the number of lymph nodes examined as a multi-categorical variable into the T and N staging system could improve prognostic predictive validity.

[Analysis of influencing factors and clinical value of anterior peritoneal reflection for patients with rectal cancer]

Objectives: To investigate the factors influencing the height of anterior peritoneal reflection (APR) for patients with rectal cancer, and to analyze the relationship between the APR and the lateral lymph node metastasis. Methods: Clinical data of 432 patients with tumor located within and below APR were retrospectively collected from the rectal cancer database at the Department of General Surgery, Peking Union Medical College Hospital from August 2020 to September 2022. Ninty-eight non-rectal cancer patients were also enrolled as a control group. There were 308 males and 124 females in the tumor group, aged (M(IQR)) 62 (16) years (range: 24 to 85 years) and 53 males and 45 females in the control group, aged 60 (22) years (range: 27 to 87 years). The APR height, pelvis, and tumor-related parameters were measured by MRI. A multifactor linear regression model was established to analyze the dependent correlation factors of APR height. These factors of the two groups were matched by propensity score matching and their APR heights were compared after matching. An ordinal Logistic regression model was established to explore the relationship between APR-related parameters and radiographic lateral lymph node metastasis. Results: The APR height of the tumor group was (98.7±14.4) mm (range: 43.3 to 154.0 mm) and the control group was (95.1±12.7) mm (range: 68.0 to 137.9 mm). Multivariable linear regression revealed that the greater the weight (B=0.519, 95%CI: 0.399 to 0.640, P<0.01), the anterior pelvic depth (B=0.109, 95%CI: 0.005 to 0.213, P=0.039) and the smaller the bi-ischial diameter (B=-0.172, 95%CI:-0.294 to -0.049, P=0.006), the higher the APR height. The tumor group had a higher APR height than the control group after propensity score matching ((98.3±14.2) mm vs. (95.1±12.7) mm, t=-1.992, P=0.047). Ordinal Logistic regression indicated that the longer segment of the tumor invade the nonperitoneal rectum was an independent influencing factor of radiographic lateral lymph node metastasis (OR=1.016, 95%CI: 1.002 to 1.030, P=0.021), while the distance between the anal verge and the tumor was not (OR=0.986, 95%CI: 0.972 to 1.000, P=0.058). Conclusions: The higher the weight, the deeper and narrower the pelvis, the higher the APR height. There is a certain relationship between APR and lateral lymph node metastasis on imaging.

[Advances in three-dimensional tumor models for colorectal cancer]

Conventional tumor culture models include two-dimensional tumor cell cultures and xenograft models. The former has disadvantages including lack of tumor heterogeneity and poor clinical relevance, while the latter are limited by the slow growth, low engraftment successful rate, and high cost. In recent years, in vitro three-dimensional (3D) tumor models have emerged as the tool to better recapitulate the spatial structure and the in vivo environment of tumors. In addition, they preserve the pathological and genetic features of tumor cells and reflect the complex intracellular and extracellular interactions of tumors, which have become a powerful tool for investigating the tumor mechanism, drug screening, and personalized cancer treatment. 3D tumor model technologies such as spheroids, organoids, and microfluidic devices are maturing. Application of new technologies such as co-culture, 3D bioprinting, and air-liquid interface has further improved the clinical relevance of the models. Some models recapitulate the tumor microenvironment, and some can even reconstitute endogenous immune components and microvasculature. In recent years, some scholars have combined xenograft models with organoid technology to develop matched in vivo/in vitro model biobanks, giving full play to the advantages of the two technologies, and providing an ideal research platform for individualized precision therapy for specific molecular targets in certain subtypes of tumors. So far, the above technologies have been widely applied in the field of colorectal cancer research. Our research team is currently studying upon the application of patient-derived tumor cell-like clusters, a self-assembly 3D tumor model, in guiding the selection of postoperative chemotherapy regimens for colorectal cancer. A high modeling success rate and satisfactory results in the drug screening experiments have been achieved. There is no doubt that with the advancement of related technologies, 3D tumor models will play an increasingly important role in the research and clinical practice of colorectal cancer.

Improved Measurement of the Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Reactor neutrino experiments play a crucial role in advancing our knowledge of neutrinos. In this Letter, the evolution of the flux and spectrum as a function of the reactor isotopic content is reported in terms of the inverse-beta-decay yield at Daya Bay with 1958 days of data and improved systematic uncertainties. These measurements are compared with two signature model predictions: the Huber-Mueller model based on the conversion method and the SM2018 model based on the summation method. The measured average flux and spectrum, as well as the flux evolution with the ^{239}Pu isotopic fraction, are inconsistent with the predictions of the Huber-Mueller model. In contrast, the SM2018 model is shown to agree with the average flux and its evolution but fails to describe the energy spectrum. Altering the predicted inverse-beta-decay spectrum from ^{239}Pu fission does not improve the agreement with the measurement for either model. The models can be brought into better agreement with the measurements if either the predicted spectrum due to ^{235}U fission is changed or the predicted ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu spectra are changed in equal measure.

Precision Measurement of Reactor Antineutrino Oscillation at Kilometer-Scale Baselines by Daya Bay

We present a new determination of the smallest neutrino mixing angle θ_{13} and the mass-squared difference Δm_{32}^{2} using a final sample of 5.55×10^{6} inverse beta-decay (IBD) candidates with the final-state neutron captured on gadolinium. This sample is selected from the complete dataset obtained by the Daya Bay reactor neutrino experiment in 3158 days of operation. Compared to the previous Daya Bay results, selection of IBD candidates has been optimized, energy calibration refined, and treatment of backgrounds further improved. The resulting oscillation parameters are sin^{2}2θ_{13}=0.0851±0.0024, Δm_{32}^{2}=(2.466±0.060)×10^{-3}  eV^{2} for the normal mass ordering or Δm_{32}^{2}=-(2.571±0.060)×10^{-3}  eV^{2} for the inverted mass ordering.

[Predictive value of MRI pelvic measurements for "difficult pelvis" during total mesorectal excision]

Objective: Total mesorectal resection (TME) is difficult to perform for rectal cancer patients with anatomical confines of the pelvis or thick mesorectal fat. This study aimed to evaluate the ability of pelvic dimensions to predict the difficulty of TME, and establish a nomogram for predicting its difficulty. Methods: The inclusion criteria for this retrospective study were as follows: (1) tumor within 15 cm of the anal verge; (2) rectal cancer confirmed by preoperative pathological examination; (3) adequate preoperative MRI data; (4) depth of tumor invasion T1-4a; and (5) grade of surgical difficulty available. Patients who had undergone non-TME surgery were excluded. A total of 88 patients with rectal cancer who underwent TME between March 2019 and November 2021 were eligible for this study. The system for scaling difficulty was as follows: Grade I, easy procedure, no difficulties; Grade II, difficult procedure, but no impact on specimen quality (complete TME); Grade III, difficult procedure, with a slight impact on specimen quality (near-complete TME); Grade IV: very difficult procedure, with remarkable impact on specimen quality (incomplete TME). We classified Grades I-II as no surgical difficulty and grades III-IV as surgical difficulty. Pelvic parameters included pelvic inlet length, anteroposterior length of the mid-pelvis, pelvic outlet length, pubic tubercle height, sacral length, sacral depth, distance from the pubis to the pelvic floor, anterior pelvic depth, interspinous distance, and inter-tuberosity distance. Univariate and multivariate logistic regression analyses were performed to identify the factors associated with the difficulty of TME, and a nomogram predicting the difficulty of the procedure was established. Results: The study cohort comprised 88 patients, 30 (34.1%) of whom were classified as having undergone difficult procedures and 58 (65.9%) non-difficult procedures. The median age was 64 years (56-70), 51 patients were male and 64 received neoadjuvant therapy. The median pelvic inlet length, anteroposterior length of the mid-pelvis, pelvic outlet length, pubic tubercle height, sacral length, sacral depth, distance from the pubis to the pelvic floor, anterior pelvic depth, interspinous distance, and inter-tuberosity distance were 12.0 cm, 11.0 cm, 8.6 cm, 4.9 cm, 12.6 cm, 3.7 cm, 3.0 cm, 13.3 cm, 10.2 cm, and 12.2 cm, respectively. Multivariable analyses showed that preoperative chemoradiotherapy (OR=4.97,95% CI: 1.25-19.71, P=0.023), distance between the tumor and the anal verge (OR=1.31, 95% CI: 1.02-1.67, P=0.035) and pubic tubercle height (OR=3.36, 95% CI: 1.56-7.25, P=0.002) were associated with surgical difficulty. We then built and validated a predictive nomogram based on the above three variables (AUC = 0.795, 95%CI: 0.696-0.895). Conclusion: Our research demonstrated that our system for scaling surgical difficulty of TME is useful and practical. Preoperative chemoradiotherapy, distance between tumor and anal verge, and pubic tubercle height are risk factors for surgical difficulty. These data may aid surgeons in planning appropriate surgical procedures.

[Risk factor and early diagnosis of anastomotic leakage after rectal cancer surgery]

Anastomotic leakage (AL) is one of the most serious complications after sphincter- preserving surgery for rectal cancer, which can significantly prolong the length of stay of patients, increase perioperative mortality, cause dysfunction, shorten overall survival and recurrence-free survival of patients. In order to reduce the serious consequences caused by AL, prediction of AL through preoperative and intraoperative risk factors are of great importance. However, the influences of neoadjuvant chemoradiotherapy, protective stoma, laparoscopic surgery and some intraoperative manipulations on AL are still controversial. Through the auxiliary judgment of anastomotic blood supply during operation, such as indocyanine green imaging, hemodynamic ultrasound, etc., it is expected to achieve the source control of AL. Early diagnosis of AL can be achieved by attention to clinical manifestations and drainage, examination of peripheral blood, drainage and intestinal flora, identification of high risk factors such as fever, diarrhea and increased infectious indicators, and timely administration of CT with contrast enema.

Safely Modified Laparoscopic Liver Resection for Segment VI and/or VII Hepatic Lesions Using the Left Lateral Decubitus Position

Purpose

To explore the feasibility and safety of using the left lateral decubitus position (LLDP) to perform laparoscopic liver resection (LLR) for the treatment of hepatic lesions in segment VI and/or VII.

Patients and Methods

Clinical data concerning 50 patients underwent LLR including 25 patients in the LLDP and the other 25 patients in the routine operative position (ROP) at Shulan (Hangzhou) Hospital Affiliated to Zhejiang Shuren University Shulan International Medical College (Hangzhou, China) and Shulan (Quzhou) Hospital between March 2019 and May 2022 were retrospectively analyzed. All of the patients underwent LLR while in the LLDP or the ROP for the treatment of hepatic lesions located in segment VI and/or VII.

Results

The preoperative clinical and laboratory parameters were comparable between the two groups (P > 0.05). All patients completed the surgery successfully. There were two patients required conversion to open resection in the ROP comparing with zero in the LLDP. The mean operative time was 256.9 ± 132.7 minutes in LLDP and 255.7 ± 92.1 minutes in ROP, while the median perioperative blood loss was 100 mL (range: 50–300 mL) in LLDP and 200 mL (range: 50–425 mL), respectively. The postoperative pathological examination showed that margin-negative resection was achieved all of the cases. The important postoperative parameters all returned to normal within five days after the LLR. The mean postoperative hospital stay (15.6 vs 19.3 days; p < 0.05) and the extraction of the drainage tube time (7.8 vs 10.4 days; p < 0.05) were shorter for patients in LLDP.

Conclusion

The LLDP represents a safe and feasible position for performing LLR in selected patients with lesions in segment VI and/or VII. LLR in the LLDP is helpful in terms of the exposure of the surgical field and the recovery of the patient.

First Measurement of High-Energy Reactor Antineutrinos at Daya Bay

This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12 MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10 MeV is rejected with a significance of 6.2 standard deviations. A 29% antineutrino flux deficit in the prompt energy region of 8-11 MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-Q_{β} isotopes in commercial reactors.

[Analysis of prognosis factors of postoperative cardiac complications in colorectal cancer patients with comorbid coronary artery disease]

Objective: To examine the prognosis factors of postoperative cardiac complications in colorectal cancer patients co-morbidated with coronary artery disease. Methods: Clinical data of 449 patients colorectal cancer patients co-morbidated with coronary artery disease accepted redical surgery from April 2013 to April 2020 at Department of General Surgery, Peking Union Medical College Hospital were analyzed retrospectively. There were 306 males and 143 females, aging (68.7±8.9) years (range: 44 to 89 years). Postoperative acute coronary syndrome, new-onset arrhythmia and heart failure that causes clinical symptoms were recorded as cardiac complications. t test, χ2 test and Fisher exact test were used for univariate analysis of prognosis factors of postoperative cardiac events. The variables with P<0.05 were included in the multivariate Logistic regression was used to determine the independent prognosis factors. Results: After surgery, 44 patients (9.8%) suffered from at least one cardiac event, including 30 patients with acute coronary syndrome, 19 patients with new-onset arrhythmia and 9 patients with heart failure. There were 3 deaths in the cohort within 30 days after surgery. Two patients died from cardiac-related complications, and one from septic shock due to postoperative anastomotic leaks. On Univariate analysis showed that cardiac complications were associated with age ≥80 years, co-morbidated diabetes, emergency surgery, re-operation, anastomotic leakage, intestinal flora disorder and elevation of preoperative neutrophil-lymphocyte ratio (χ2: 4.308 to 12.219, all P<0.05). Multivariate Logistic regression analysis identified age ≥80 years(OR=3.195, 95%CI: 1.379 to 7.407, P=0.007), co-morbidated diabetes (OR=2.551, 95%CI: 1.294 to 5.025, P=0.007), emergency surgery (OR=4.717, 95%CI: 1.052 to 20.833, P=0.043), and elevated preoperative neutrophil-lymphocyte ratio (OR=1.114, 95%CI: 1.018 to 1.218, P=0.018) as independent prognosis factors for cardiac complications. Conclusions: Emergency surgery, advanced age, co-morbidated type 2 diabetes and elevated preoperative neutrophil-lymphocyte ratio may increase the risk of postoperative cardiac complications in colorectal cancer patients with coronary artery disease. Surgeons should strictly master surgical indications, pay attention to preoperative assessment, perioperative monitoring, and diagnosis and treatment of postoperative complications in order to reduce the risk of complications.

[Safety and prognosis analysis of transanal total mesorectal excision versus laparoscopic mesorectal excision for mid-low rectal cancer]

Objective: To compare the short-term and long-term outcomes between transanal total mesorectal excision (taTME) and laparoscopic total mesorectal excision (laTME) for mid-to-low rectal cancer and to evaluate the learning curve of taTME. Methods: This study was a retrospective cohort study. Firstly, consecutive patients undergoing total mesorectal excision who were registered in the prospective established database of Division of Colorectal Diseases, Department of General Surgery, Peking Union Medical College Hospital during July 2014 to June 2020 were recruited. The enrolled patients were divided into taTME and laTME group. The demographic data, clinical characteristics, neoadjuvant treatment, intraoperative and postoperative complications, pathological results and follow-up data were extracted from the database. The primary endpoint was the incidence of anastomotic leakage and the secondary endpoints included the 3-year disease-free survival (DFS) and the 3-year local recurrence rate. Independent t-test for comparison between groups of normally distributed measures; skewed measures were expressed as M (range). Categorical variables were expressed as examples (%) and the χ(2) or Fisher exact probability was used for comparison between groups. When comparing the incidence of anastomotic leakage, 5 variables including sex, BMI, clinical stage evaluated by MRI, distance from tumor to anal margin evaluated by MRI, and whether receiving neoadjuvant treatment were balanced by propensity score matching (PSM) to adjust confounders. Kaplan-Meier curve and Log-rank test were used to compare the DFS of two groups. Cox proportional hazard model was used to analyze and determine the independent risk factors affecting the DFS of patients with mid-low rectal cancer. Secondly, the data of consecutive patients undergoing taTME performed by the same surgical team (the trananal procedures were performed by the same main surgeon) from February 2017 to March 2021 were separately extracted and analyzed. The multidimensional cumulative sum (CUSUM) control chart was used to draw the learning curve of taTME. The outcomes of 'mature' taTME cases through learning curve were compared with laTME cases and the independent risk factors of DFS of 'mature' cases were also analyzed. Results: Two hundred and forty-three patients were eventually enrolled, including 182 undergoing laTME and 61 undergoing taTME. After PSM, both fifty-two patients were in laTME group and taTME group respectively, and patients of these two groups had comparable characteristics in sex, age, BMI, clinical tumor stage, distance from tumor to anal margin by MRI, mesorectal fasciae (MRF) and extramural vascular invasion (EMVI) by MRI and proportion of receiving neoadjuvant treatment. After PSM, as compared to laTME group, taTME group showed significantly longer operation time [(198.4±58.3) min vs. (147.9±47.3) min, t=-4.321, P<0.001], higher ratio of blood loss >100 ml during surgery [17.3% (9/52) vs. 0, P=0.003], higher incidence of anastomotic leakage [26.9% (14/52) vs. 3.8% (2/52), χ(2)=10.636, P=0.001] and higher morbidity of overall postoperative complications [55.8%(29/52) vs. 19.2% (10/52), χ(2)=14.810, P<0.001]. Total harvested lymph nodes and circumferential resection margin involvement were comparable between two groups (both P>0.05). The median follow-up for the whole group was 24 (1 to 72) months, with 4 cases lost, giving a follow-up rate of 98.4% (239/243). The laTME group had significantly better 3-year DFS than taTME group (83.9% vs. 73.0%, P=0.019), while the 3-year local recurrence rate was similar in two groups (1.7% vs. 3.6%, P=0.420). Multivariate analysis showed that and taTME surgery (HR=3.202, 95%CI: 1.592-6.441, P=0.001) the postoperative pathological staging of UICC stage II (HR=13.862, 95%CI:1.810-106.150, P=0.011), stage III (HR=8.705, 95%CI: 1.104-68.670, P=0.040) were independent risk factors for 3-year DFS. Analysis of taTME learning curve revealed that surgeons would cross over the learning stage after performing 28 cases. To compare the two groups excluding the cases within the learning stage, there was no significant difference between two groups after PSM no matter in the incidence of anastomotic leakage [taTME: 6.7%(1/15); laTME: 5.3% (2/38), P=1.000] or overall complications [taTME: 33.3%(5/15), laTME: 26.3%(10/38), P=0.737]. The taTME was still an independent risk factor of 3-year DFS only analyzing patients crossing over the learning stage (HR=5.351, 95%CI:1.666-17.192, P=0.005), and whether crossing over the learning stage was not the independent risk factor of 3-year DFS for mid-low rectal cancer patients undergoing taTME (HR=0.954, 95%CI:0.227-4.017, P=0.949). Conclusions: Compared with conventional laTME, taTME may increase the risk of anastomotic leakage and compromise the oncological outcomes. Performing taTME within the learning stage may significantly increase the risk of postoperative anastomotic leakage.

[Quality of life of patients with locally advanced rectal cancer after neoadjuvant therapy and sphincter-preserving surgery]

Objective: To investigate quality of life (QoL) of patients with locally advanced rectal cancer (LARC) who underwent low anterior resection with protective stoma under neoadjuvant therapy mode, and to explore the changes of QoL of patients from before neoadjuvant therapy to 12 months after stoma reversal. Methods: A descriptive case series study was carried out. A retrospective study was performed on patients with mid and low LARC who received complete neoadjuvant long course radiotherapy and chemotherapy, followed by radical low anterior resection (LAR) combined with protective stoma at Peking Union Medical College Hospital from December 2017 to January 2020. Inclusion criteria: (1) patients with rectal MRI assessment of mT3-4b or mN1-2 without distant metastasis (M0) before neoadjuvant therapy; (2) distance from tumor lower margin to the anal verge <12 cm; (3) rectal adenocarcinoma confirmed by biopsy before neoadjuvant therapy; (4) complete cycle of neoadjuvant therapy; (5) patients undergoing radical LAR with sphincter preservation and protective ostomy; (6) patients receiving follow-up for more than 12 months after stoma reversal. Exclusion criteria: (1) patients as grade Ⅳ to Ⅴclassified by the American Society of Anesthesiologists (ASA); (2) patients with multiple primary colorectal cancer; (3) patients with history of other malignant tumors in the past 5 years; (4) patients of emergency surgery; (5) pregnant or lactating women; (6) patients with history of severe mental illness; (7) patients with contraindication of MRI, radiotherapy, chemotherapy, or surgical treatment. A total of 83 patients were enrolled, including 51 males and 28 females with median age of 59 years and mean BMI of (24.4±3.1) kg/m(2). EORTC QLQ-CR29, international erectile function index (IIEF), Wexner constipation score and low anterior resection syndrome (LARS) score were applied to investigate the QoL of the patients before neoadjuvant therapy, 3 and 12 months after ostomy reversal, including rectal anal function and sexual function. M (P25, P75) was used for the scores of the scale. Results: (1) EORTC QLQ-CR29 score showed that before neoadjuvant therapy, before surgery, 3 months and 12 months after ostomy reversal, anxiety [64.4 (52, 0, 82.5), 75.3 (66.0, 89.5), 82.6 (78.5, 90.0), 83.6 (78.0, 91.0)] and concern about body image [76.8 (66.0, 92.0), 81.1 (76.5, 91.5), 85.5 (82.5, 94.0), 86.1 (82.0, 92.0)] were improved (all P<0.01); pelvic pain [5.4 (2.0, 8.0), 5, 0 (2.0, 7.8), 3.9 (1.0, 5.0), 3.0 (1.0, 5.0)], urinary incontinence [15.7 (7.0, 22.0), 11.1 (0, 17.5), 10.0 (0, 17.0), 9.9 (0, 16.0)], impotence [14.3 (4.2, 19.0), 12.2 (0, 16.8), 5.6 (0, 10.0), 5.2 (0.2, 8.0)], urinate [26.4 (13.0, 38.5), 13.9 (0, 20.0), 13.4 (2.5, 21.5), 13.2 (2.0, 20.0)] and mucous bloody stool [4.7 (3.0, 6.0), 2.6 (0, 5.0), 2.2 (0, 5.0), 1.9 (0, 4.0)] were improved as well (all P<0.01). The scores fluctuated in the improvement of male sexual function, abdominal pain, dry mouth, worry about body mass change, skin pain and dyspareunia, but the symptoms were significantly improved after ostomy reversal compared with before neoadjuvant therapy (all P<0.05). There were no significant changes in female sexual function, dysuria, dysgeusia and fecal incontinence after ostomy reversal compared with before neoadjuvant therapy (all P>0.05). (2) IIEF scale showed that all scores were similar before and after neoadjuvant therapy (all P>0.05). (3) Rectal and anal function scale revealed that before neoadjuvant therapy, before operation, 3 months and 12 months after stoma reversal, gas incontinence [3.1 (0, 4.0), 2.3 (0, 4.0), 1.8 (0, 4.0), 1.2 (0, 3.0)] and urgent defecation [7.2 (0, 11.0), 5.2 (0, 11.0), 2.9 (0, 9.0), 1.7 (0, 0)] were improved (all P<0.001). In terms of improving incomplete emptying sensation, the symptoms fluctuated, but the symptoms improved significantly after ostomy reversal compared with before neoadjuvant therapy (all P<0.05). While the symptoms of assistance with defecation [0 (0, 0), 0.7 (0, 1.0), 0.6 (0, 1.0), 0.7 (0, 1.0)] and defecation failure [0.2 (0, 0), 1.0 (0, 2.0), 0.8 (0, 1.5), 0.8 (0, 1.0)] showed a worsening trend (all P<0.001). Stratified analysis was performed on patients with different efficacy of neoadjuvant therapy to compare the changes in QoL before and after neoadjuvant therapy. Patients with less sensitive and more sensitive neoadjuvant therapy showed similar changes in function and symptoms. Patients with less sensitive therapy showed significant improvement in dysuria, urinary incontinence, skin pain and dyspareunia (all P<0.05), and the symptom of defecation frequency in more sensitive patients was significantly improved (P<0.05). Conclusions: For patients with LARC, neoadjuvant radiochemotherapy combined with radical LAR and protective stoma can improve QoL in many aspects. It is noted that patients show a worsening trend in the need for assistance with defecation and in defecation failure.

[Risk factors of postoperative surgical site infection in colon cancer based on a single center database]

Objective: To explore the incidence and risk factors of postoperative surgical site infection (SSI) after colon cancer surgery. Methods: A retrospective case-control study was performed. Patients diagnosed with colon cancer who underwent radical surgery between January 2016 and May 2021 were included, and demographic characteristics, comorbidities, laboratory tests, surgical data and postoperative complications were extracted from the specialized prospective database at Department of General Surgery, Peking Union Medical College Hospital. Case exclusion criteria: (1) simultaneously multiple primary colon cancer; (2) segmental resection, subtotal colectomy, or total colectomy; (3) patients undergoing colostomy/ileostomy during the operation or in the state of colostomy/ileostomy before the operation; (4) patients receiving natural orifice specimen extraction surgery or transvaginal colon surgery; (5) patients with the history of colectomy; (6) emergency operation due to intestinal obstruction, perforation and acute bleeding; (7) intestinal diversion operation; (8) benign lesions confirmed by postoperative pathology; (9) patients not following the colorectal clinical pathway of our department for intestinal preparation and antibiotic application. Univariate analysis and multivariate analysis were used to determine the risk factors of SSI after colon cancer surgery. Results: A total of 1291 patients were enrolled in the study. 94.3% (1217/1291) of cases received laparoscopic surgery. The incidence of overall SSI was 5.3% (69/1291). According to tumor location, the incidence of SSI in the right colon, transverse colon, left colon and sigmoid colon was 8.6% (40/465), 5.2% (11/213), 7.1% (7/98) and 2.1% (11/515) respectively. According to resection range, the incidence of SSI after right hemicolectomy, transverse colectomy, left hemicolectomy and sigmoid colectomy was 8.2% (48/588), 4.5% (2/44), 4.8% (8 /167) and 2.2% (11/492) respectively. Univariate analysis showed that preoperative BUN≥7.14 mmol/L, tumor site, resection range, intestinal anastomotic approach, postoperative diarrhea, anastomotic leakage, postoperative pneumonia, and anastomotic technique were related to SSI (all P<0.05). Multivariate analysis revealed that anastomotic leakage (OR=22.074, 95%CI: 6.172-78.953, P<0.001), pneumonia (OR=4.100, 95%CI: 1.546-10.869, P=0.005), intracorporeal anastomosis (OR=5.288, 95%CI: 2.919-9.577,P<0.001) were independent risk factors of SSI. Subgroup analysis showed that in right hemicolectomy, the incidence of SSI in intracorporeal anastomosis was 19.8% (32/162), which was significantly higher than that in extracorporeal anastomosis (3.8%, 16/426, χ(2)=40.064, P<0.001). In transverse colectomy [5.0% (2/40) vs. 0, χ(2)=0.210, P=1.000], left hemicolectomy [5.4% (8/148) vs. 0, χ(2)=1.079, P=0.599] and sigmoid colectomy [2.1% (10/482) vs. 10.0% (1/10), χ(2)=2.815, P=0.204], no significant differences of SSI incidence were found between intracorporeal anastomosis and extracorporeal anastomosis (all P>0.05). Conclusions: The incidence of SSI increases with the resection range from sigmoid colectomy to right hemicolectomy. Intracorporeal anastomosis and postoperative anastomotic leakage are independent risk factors of SSI. Attentions should be paid to the possibility of postoperative pneumonia and actively effective treatment measures should be carried out.

Joint Determination of Reactor Antineutrino Spectra from ^{235}U and ^{239}Pu Fission by Daya Bay and PROSPECT

A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.

[Application of electric tube stapler in laparoscopic colorectal tumor surgery]

Objective: To investigate the application of electric tube stapler in laparoscopic colorectal tumor surgery. Methods: A descriptive case series study was conducted. Clinical data of patients who underwent laparoscopic colorectal surgery in Peking Union Medical College Hospital in August 2021 using domestic electric tube stapler were collected to analyze the occurrence of postoperative anastomotic leakage, anastomotic bleeding and other complications as well as postoperative intestinal function recovery. Results: A total of 11 patients with colorectal tumor were enrolled in this study, including 8 males and 3 females. Eight patients underwent laparoscopic low anterior resection (1 patient underwent protective ileostomy), and three patients underwent laparoscopic sigmoid carcinoma radical resection. During operation, power system failure of stapler occurred in 1 patient, and the replacement manual device was used to complete the anastomosis. No anastomotic leakage or bleeding occurred in the cohort of patients. There was no conversion to laparotomy or conventional anastomosis. One patient developed acute myocardial infarction 2 days after surgery. The average time to the first flatus after surgery was (2.4±0.8) days and the average length of hospital stay was (10.0±6.1) days. Conclusions: The application of electric tube stapler in laparoscopic colorectal tumor surgery has many advantages, such as safe and effective anastomosis, low morbidity of postoperative complications, and rapid recovery of intestinal function. Domestic electric tube stapler can be applied in minimally invasive surgery for colorectal tumor.

[Questionnaire investigation of radiation rectal injury with anxiety, depression and somatic disorder]

Objective: To observe the incidence and treatment of radiation rectal injury complicated with anxiety, depression and somatic symptom disorder. Methods: A cross-sectional survey research method was carried out. Patients with radiation rectal injury managed by members of the editorial board of Chinese Journal of Gastrointestinal Surgery were the subjects of investigation. The inclusion criteria of the survey subjects: (1) patients suffered from pelvic tumors and received pelvic radiotherapy; (2) colonoscopy showed inflammatory reaction or ulcer in the rectum. Exclusion criteria: (1) patient had a history of psycho-somatic disease before radiotherapy; (2) patient was unable to use a smart phone, unable to read and understand the questions in the questionnaire displayed on the phone; (3) patient refused to sign an informed consent form. According to the SOMA self-rating scale, PHQ-15 self-rating scale, GAD-7 and PHQ-9 self-rating scale, the electronic questionnaire of "Psychological Survey of Radiation Proctitis" was designed. The questionnaire was sent to patients with radiation rectal injury managed by the committee through the WeChat group. Observational indicators: (1) radiation rectal injury symptom assessment: using SOMA self-rating scale, radiation rectal injury symptom classification: mild group (≤3 points), moderate group (4-6 points) and severe group (> 6 points); (2) incidence of anxiety, depression and physical disorder: using GAD-7, PHQ-9 and PHQ-15 self-rating scales respectively for assessment; (3) correlation of radiation rectal injury symptom grading with anxiety, depression, and somatic symptom disorder. Results: Seventy-one qualified questionnaires were collected, of which 41 (56.9%) were from Guangzhou. Among the 71 patients, 6 were males and 65 were females; the mean age was (55.7±9.3) years old and 48 patients (67.6%) were less than 60 years old; the median confirmed duration of radiation rectal injury was 2.0 (1.0, 5.0) years. (1) Evaluation of symptoms of radiation rectal injury: 18 cases of mild (25.4%), 27 cases of moderate (38.0%), and 26 cases of severe (36.6%). (2) Incidence of anxiety, depression and somatic disorder: 12 patients (16.9%) without comorbidities; 59 patients (83.1%) with anxiety, depression, or somatic disorder, of whom 2 patients only had anxiety, 1 patient only had depression, 9 only had somatic disorder, 2 had anxiety plus depression, 4 had anxiety plus somatic disorder, 2 had depression plus somatic disorder, and 40 had all three symptoms. (3) correlation of radiation rectal injury grading with anxiety, depression, and somatic symptom disorder: as compared to patients in mild group and moderate group, those in severe group had higher severity of anxiety and somatic symptom disorder (Z=-2.143, P=0.032; Z=-2.045, P=0.041), while there was no statistically significant difference of depression between mild group and moderate group (Z=-1.176, P=0.240). Pearson correlation analysis revealed that radiation rectal injury symptom score was positively correlated with anxiety (r=0.300, P=0.013), depression (r=0.287, P=0.015) and somatic symptom disorder (r=0.344, P=0.003). Conclusions: The incidence of anxiety, depression, and somatic symptom disorder in patients with radiation rectal injury is extremely high. It is necessary to strengthen the diagnosis and treatment of somatic symptom disorder, so as to alleviate the symptoms of patients with pelvic perineum pain and improve the quality of life.

[Diagnosis and treatment of anastomotic leak after low anterior resection for rectal cancer: current status and future prospect]

Anastomotic leak is one of inevitable postoperative complications of rectal cancer. With the improvement of surgical techniques, the enhancement of the cognization of rectal cancer, and the development of surgical instruments, surgical procedures of rectal cancer are getting more sophisticated. The anastomosis is performed lower and lower, however the incidence of anastomotic leak is not significantly decreased. In addition, different from intraperitoneal anastomotic leak, the low rectal anastomotic leak after low anterior resection has many special issues in the diagnosis and treatment in clinic. The incidence of peritonitis caused by low anastomotic leak is low, the onset time is late, and symptoms of peritonitis are mild. So most low anastomotic leak is treated conservatively, second surgical repair or resection of anastomotic site is rarely performed, and proximal intestinal diversion is commonly performed. In the prevention of low anastomotic leak, some techniques and precautions during the perioperative period and identification of high risk factors might play important roles. Combined our clinical experiences, we introduced the diagnosis, treatment, prevention and research progression of low anastomotic leak after anterior resection of low rectal cancer, we hope it would be helpful.

[Protective colostomy and protective ileostomy for the prevention of anastomotic leak in patients with rectal cancer after neoadjuvant chemoradiotherapy and radical surgery]

Objective: To investigate whether protective colostomy and protective ileostomy have different impact on anastomotic leak for rectal cancer patients after neoadjuvant chemoradiotherapy (nCRT) and radical surgery. Methods: A retrospectively cohort study was conducted. Inclusion criteria: (1) Standard neoadjuvant therapy before operation; (2) Laparoscopic rectal cancer radical resection was performed; (3) During the operation, the protective enterostomy was performed including transverse colostomy and ileostomy; (4) The patients were followed up regularly; (5) Clinical data was complete. Exclusion criteria: (1) Colostomy and radical resection of rectal cancer were not performed at the same time; (2) Intestinal anastomosis is not included in the operation, such as abdominoperineal resection; (3) Rectal cancer had distant metastasis or multiple primary colorectal cancer. Finally 208 patients were included in this study. They suffered from rectal cancer and underwent protective stoma in radical surgery after nCRT at our hospital from January 2014 to December 2018. There were 148 males and 60 females with age of (60.5±11.1) years. They were divided into protective transverse colostomy group (n=148) and protective ileostomy group (n=60). The main follow up information included whether the patient has anastomotic leak and the type of leak according to ISREC Grading standard. Besides, stoma opening time, stoma flow, postoperative hospital stay, stoma related complications and postoperative intestinal flora were also collected. Results: A total of 28 cases(13.5%) suffered from anastomotic leak and 26 (92.9%) of them happened in the early stage after surgery (less than 30 days) . As for these early-stage leak, ISREC Grade A happened in 11 cases(42.3%), grade B in 15 cases(57.7%) and no grade C occurred. There was no significant difference in the incidence [12.8% (19/148) vs. 15.0% (9/60) , χ(2)=0.171, P=0.679] or type [Grade A: 5.4%(8/147) vs. 5.1%(3/59); Grade B: 6.8%(10/147) vs. 8.5%(5/59), Z=0.019, P=1.000] of anastomotic leak between the transverse colostomy group and ileostomy group (P>0.05), as well as operation time, postoperative hospital stay, drainage tube removal time or stoma reduction time (P>0.05). There were 10 cases (6.8%) and 24 cases (40.0%) suffering from intestinal flora imbalance in protective transverse colostomy and protective ileostomy group, respectively (χ(2)=34.503, P<0.001). Five cases (8.3%) suffered from renal function injury in the protective ileostomy group, while protective colostomy had no such concern (P=0.002). The incidence of peristomal dermatitis in the protective colostomy group was significantly lower than that in the protective ileostomy group [12.8% (9/148) vs. 33.3%(20/60), χ(2)=11.722, P=0.001]. Conclusions: It is equally feasible and effective for rectal cancer patients after nCRT to carry out protective transverse colostomy or ileostomy in radical surgery. However, we should pay more attention to protective ileostomy patients, as they are at high risk of intestinal flora imbalance, renal function injury and peristomal dermatitis.

[Prognosis and complications of local excision for rectal cancer after neoadjuvant chemoradiotherapy]

Objective: To investigate the prognosis and postoperative complications of local excision for rectal cancer after neoadjuvant chemoradiotherapy (nCRT). Methods: A descriptive case series study was carried out. Patient inclusion criteria: (1) patients who underwent local excision by transanal endoscopic microsurgery (TEM) after nCRT; (2) magnetic resonance evaluated tumor regression grade (mrTRG) as 1, 2 after nCRT;(3) American Society of Anesthesiologists class I to III. Patient exclusion criteria: (1) with multiple primary colorectal cancers; (2) with other malignant tumors within five years; (3) with emergency surgicery indications like digestive tract obstruction, perforation or bleeding. Clinicopathological and follow-up data of rectal cancer patients with obvious tumor regression after nCRT who underwent local excision in Peking Union Medical College Hospital from January 2010 to August 2019 were retrospectively collected. Outcome measures included disease-free survival (DFS), short-term postoperative complications, and at postoperative 1-year during follow up, gas continence, fecal continence, and quality of life (using the EORTC QLQ-CR29 scale, higher score indicated worse quality of life) at postoperative 1-year. Results: A total of 40 patients were included in this study. There were 27 males and 13 females with an average age of (66.7±12.3) years. Preoperative rectal ultrasound and other imaging examinations indicated that the tumor was located in the anterior wall in 16 cases, the lateral wall in 12 cases, and the posterior wall in 12 cases. The distance between the lower margin of the tumor and the anal verge was (4.3±1.2) cm before nCRT and (5.1±0.9) cm after nCRT. According to mrTRG, 31 cases were assessed as mrTRG 1 and 9 cases as mrTRG 2. All the patients received local extended excision of rectal cancer using TEM platform. A total of 19 cases(47.5%) suffered from complications within one month postoperatively. Clavien-Dindo grade I complications happened in 14 cases, grade II in 3 patients, and grade III in 2 cases, who all were healed by conservative treatment. Except that 2 patient presented severe low anterior resection syndrome (LARS) at 1 year postoperatively, no severe anal dysfunction was found in this cohort patients. EORTC QLQ CR29 scale results for quality of life showed that at 1 year after TEM excision, except taste (Z=-1.968, P=0.049), anxiety (Z=-3.624, P<0.001) and skin irritation (Z=-2.420, P=0.023) were worse than the situation before neoadjuvant therapy, there were no statistically significant differences in other assessment results between pre-operation and post-operation (all P>0.05). Postoperative pathological results indicated complete tumor regression (pTRG0) in 17 cases, moderate remission (pTRG1) in 13, and mild remission (pTRG2) in 10. During the follow-up of (49.1±29.6) months, 3 patients had local recurrence and 4 had distant metastasis (3 patients with liver metastasis and 1 patient with lung metastasis followed by liver metastasis). No death was found and the 5-year disease-free survival (DFS) was 84.3%. Conclusions: Local excision through TEM following nCRT not only can be adopted as an important means to accurately determine complete clinical remission (cCR), but also has high therapeutic value for rectal cancer patients presenting cCR or near cCR, with little impact on defecatory function and quality of life. However, the morbidity of complication of TEM excision after nCRT is relatively high and there is a risk of recurrence and metastasis. Therefore, it is still necessary to strictly select the indications of local excision.

[Clinicopathological characteristics, diagnosis, and treatment of 29 cases of signet ring cell carcinoma of the rectum and sigmoid colon]

Objective: To investigate the clinicopathological characteristics and the therapeutic effects of signet ring cell carcinoma (SRCC) of rectum and sigmoid colon. Methods: Clinical data and the follow-up information of 29 SRCC patients treated in our tertiary care center from 2008 to 2018 were retrospectively reviewed. The clinicopathological features, diagnostic and therapeutic effects, and the prognostic outcomes were analyzed. Results: Among the 29 patients, 17 were male, 12 were female. The average age was (48.7±14.3) years. Colonoscopy revealed the features of diffuse circumferential thickening of the bowel wall in 20/29 cases (69.0%), while in 9/29 cases (31.0%), endoscopic biopsies showed false negative results. Twenty-five% (4/16) and 17.6% (3/17) lesions were misdiagnosed as the inflammatory changes by endoscopic rectal ultrasonography exam and rectal MRI scan, respectively. Thirteen of the 29 patients received the neoadjuvant chemoradiotherapy (NCRT), 27 patients underwent the radical resection surgeries, and 8 underwent the postoperative radiotherapy. With a median follow-up of 38.5 (3.5-87.0) months, the cumulative 3-years overall survival (OS) rate was 54.0%, and the cumulative 3-years disease-free survival (DFS) rate was 43.0%. The OS rates of patients treated with or without NCRT (non-NCRT) were 46.2% and 69.2%, respectively, without significant difference (P>0.05). The DFS rates of patients treated with or without NCRT were 45.8% and 39.2%, respectively, without significant difference (P>0.05). Parameters including age younger than 40 years and tumor size larger than 5 cm were independent potential risk factors for shortened OS (P<0.05). Conclusions: SRCC of the rectum and sigmoid colon is a rare malignant tumor with special clinical manifestations. It is younger-onset, highly malignant and with very poor prognosis. Therefore, in-depth researches with focus upon the progress of molecular oncology are urgently needed to substantially improve the therapeutic effect of this disease.

Improved Constraints on Sterile Neutrino Mixing from Disappearance Searches in the MINOS, MINOS+, Daya Bay, and Bugey-3 Experiments

Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θ_{μe} mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Δm_{41}^{2}, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CL_{s} for Δm_{41}^{2}<13  eV^{2}. Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CL_{s} for Δm_{41}^{2}<1.6 eV^{2}.

[Comparison of protective ileostomy and transverse colostomy through specimen extraction auxiliary incision following laparoscopic low anterior resection for rectal cancer]

Objective: To introduce a new technique of protective ostomy using the specimen extraction auxiliary incision following laparoscopic low anterior resection for rectal cancer, and to compare the pros and cons of loop ileostomy (LI) and loop transverse colostomy (LTC). Methods: A retrospective cohort study was performed. The data of patients who underwent laparoscopic low anterior resection for rectal cancer and ostomy using the auxiliary incision in Peking Union Medical College Hospital from January 2010 to December 2017 were retrospectively analyzed. Inclusion criteria: (1) patient underwent neoadjuvant chemoradiotherapy before operation; (2) patient was classified as tumor stage II or III; (3) patient was followed up and underwent stoma closure at our center; (4) ostomy was performed through specimen extraction incision. Patients with multiple gastrointestinal carcinomas or inflammatory bowel disease were excluded. Two hundred and eight patients were included in the study and divided into the LI group (n=86) and LTC group (n=122). The operation parameters and postoperative complications were compared between the two groups. Results: There were 135 males and 73 females (1.85∶1.00). Mean age of the 208 patients was (59.6±11.6) years (range 29-85 years). There were no significant differences between LI and LTC groups in baseline data (all P>0.05). All of the patients completed surgery successfully. The severe complication rate after ostomy was 2.9% (6/208). In the fecal diversion period, LI group showed significantly faster defecation [(1.6±1.0) days vs. (2.2±1.9) days, t=-2.918, P=0.004] and lower incidence of parastomal hernia [8.1% (7/86) vs. 19.7% (24/122), χ(2)=5.290, P=0.021], but higher incidence of peristomal dermatitis [18.6% (16/86) vs. 4.9% (6/122), χ(2)=9.990, P=0.002] as compared to LTC group. The incidence of renal insufficiency was lower in LTC group, though the difference was not significant [4.9% (6/122) vs. 10.5% (9/86), χ(2)=2.320, P=0.128]. The severe complication rate after stoma closure was 1.9% (4/208). In the stoma closure period, a significantly higher incidence of wound infection was noted in LTC group [18.0% (22/122) vs. 4.7% (4/86), χ(2)=8.258, P=0.004]. There were no significant differences between the two groups in the incidence of anastomotic leakage, stenosis, and incisional hernia (all P>0.05). All complications were improved after treatment. Conclusions: Both LI and LTC through auxiliary incision following laparoscopic low anterior resection for rectal cancer are safe and feasible. LTC is an optional method for those patients with sensitive skin.

Extraction of the ^{235}U and ^{239}Pu Antineutrino Spectra at Daya Bay

This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.

[An initial exploration of the application of transanal endoscopic microsurgery in rectal cancer patients with clinical complete response after neoadjuvant chemoradiotherapy]

Objective: To preliminarily explore the value of transanal endoscopic microsurgery (TEM) in rectal cancer patients with clinical complete response (cCR) following neoadjuvant chemoradiotherapy (nCRT). Methods: Using descriptive case series method, Clinical data of 13 patients who met the criteria of nCRT and were considered to be cCR after MRI or CT scanning, digital rectal examination and colonoscopic biopsy, as well as no lymph node or distant metastasis were found, then underwent TEM from 2013 to 2016 at the Department of General Surgery of Peking Union Medical College Hospital were collected retrospectively. A 3-course combination of capecitabine and oxaliplatin (XELOX) was used for chemotherapy. Besides, a 6MV-X ray radiation was used as radiotherapy simultaneously. Six to eight weeks after completion of radiotherapy, a preoperative assessment was carried out with intrarectal ultrasound, MRI, or pelvic abdominal CT examination. TEM was performed afterwards with informed consent. Postoperative pathological findings and follow-up results were used to evaluate the value of diagnosis and treatment of TEM on those patients. Results: There were 8 males and 5 females with a median age of 63 (27-80) years. Preoperative examination showed that the lesions were located in the anterior wall in 3 cases, the posterior wall in 3 cases, the left side wall in 4 cases, and the right side wall in 3 cases. Before nCRT, the distance between tumor and anal margin was (4.8±1.1) (2.0-7.5) cm; after nCRT, this distance was (5.2±1.3) (3.0-7.5) cm. All the 13 patients underwent extended local resection of rectal cancer via TEM with the placement of urethral catheter. The average operative time was (52.2±3.7) (42-70) minutes, and the average intraoperative blood loss was (19.2±2.8) (5-30) ml. All the patients could engage in daily activities on postoperative day 1, and could cater themselves orally on postoperative day 2. The main discomfort was postoperative anal pain and foreign body sensation (n=5), which could be alleviated by non-steroidal anti-inflammatory drugs. One case had postoperative lung infection and was cured by antibiotic treatment. One case had urinary retention after removing urine catheter, and then a urine catheter was re-inserted. Average postoperative hospital stay was (2.8±2.4) (2-12) days. All specimens were completely resected via TEM. Histopathological examination confirmed that 7 specimens had achieved pathologic complete response (pCR) and the other 6 specimens had obtained partial tumor response of CAP grade 2. Seven patients with pCR received a median follow-up of 24 (8-48) months and no local recurrence or distant metastasis was reported during follow-up period. Among these 7 cases, one developed defecation dysfunction after discharge, mainly for defecation pain and even dare to defecate, who returned to normal defecation within 2 months after surgery; One developed severe anal pain within six months after surgery and the pain disappeared after symptomatic pain relief. The other 6 patients with CAP grade 2 refused to undergo further radical operation because of their strong desire in preserving anus, and received remedial adjuvant chemotherapy instead. Conclusion: For rectal cancer patients with cCR after nCRT, TEM does have certain application values if the patient has a strong desire to preserve anus.

[Analysis of Clavien-Dindo classification and its prognosis factors of complications after laparoscopic right hemicolectomy]

Objective: To analyze the Clavien-Dindo classification of complications after right hemicolectomy and to explore the prognosis factors for postoperative complications. Methods: The retrospective case-control study was adopted. The clinical data of 176 patients who underwent right hemicolectomy at Department of General Surgery, Peking Union Medical College Hospital from October 2016 to February 2018 were collected. There were 95 male and 81 female patients with age of (62.4±12.7) years. The Clavien-Dindo classification was used for postoperative complications. Univariate and multivariate analysis were used to analyze the independent prognosis factors of complications after right colon resection. Results: Of the 176 patients, 2 patients had intraoperative complications (1.1%) and 39 patients had postoperative complications (22.2%), of which 10 cases had more than two complications, with a total of 53 complications. The proportions of Clavien-Dindo grade Ⅰ, Ⅱ, Ⅲ and Ⅳ complications were 41.5% (22/53), 49.1% (26/53), 7.5% (4/53), and 1.9%(1/53). Postoperative complications were associated with age, smoking history of the last 1 year, combined organ resection, lymph node dissection, intracorporeal anastomosis, and preoperative blood AST and Ca levels (all P<0.05). The results of multivariate analysis showed that intracorporeal anastomosis (OR=5.62, 95% CI: 2.46 to 12.85, P=0.00), preoperative blood AST (OR=-0.009, 95% CI: -0.018 to 0.000, P=0.04) and Ca (OR=0.51, 95% CI: 0.08 to 0.95, P=0.02) levels were independent prognosis factors affecting complications after right hemicolectomy. Conclusions: Complications of right hemicolectomy were mainly Clavien-Dindo grade Ⅰ and Ⅱ. Laparoscopic intracorporeal anastomosis should be carefully chosen, which may increase postoperative complications.

Measurement of the Electron Antineutrino Oscillation with 1958 Days of Operation at Daya Bay

We report a measurement of electron antineutrino oscillation from the Daya Bay Reactor Neutrino Experiment with nearly 4 million reactor ν[over ¯]_{e} inverse β decay candidates observed over 1958 days of data collection. The installation of a flash analog-to-digital converter readout system and a special calibration campaign using different source enclosures reduce uncertainties in the absolute energy calibration to less than 0.5% for visible energies larger than 2 MeV. The uncertainty in the cosmogenic ^{9}Li and ^{8}He background is reduced from 45% to 30% in the near detectors. A detailed investigation of the spent nuclear fuel history improves its uncertainty from 100% to 30%. Analysis of the relative ν[over ¯]_{e} rates and energy spectra among detectors yields sin^{2}2θ_{13}=0.0856±0.0029 and Δm_{32}^{2}=(2.471_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the normal hierarchy, and Δm_{32}^{2}=-(2.575_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the inverted hierarchy.

[Oncological outcomes analysis of colorectal cancer with unfavorable histological features]

Objective: To explore the effect of unfavorable histological features on the clinical outcomes of patients receiving radical resection of colorectal cancer. Methods: A retrospective analysis of patients with colorectal cancer who received radical surgery between January 2013 and December 2015 at Department of General Surgery, Peking Union Medical College Hospital was performed. The impact of unfavorable histological features on the oncological outcomes of patients with lymph node-negative colorectal cancer were analyzed.A total of 167 patients were enrolled, including 98 males and 69 females with age of (63.6±11.6) years. Observation indicators included age, T stage, lymphovascular invasion, perineural invasion, tumor deposits, number of lymph node dissection, degree of differentiation, tissue type, and circumferential margin. Univariate analysis was performed with χ(2) test and multivariate analysis was performed with Cox regression model. Results: Univariate analysis showed that positive circumferential margins (CRM), tumor deposits and age were associated with disease free survival (DFS) rate; positive CRM, age, tumor deposits, and lymph nodes dissection less than 12 were significantly associated with overall survival (OS) rate (all P<0.05). Multivariate analysis showed that over 70 years of age (HR=1.053, 95% CI: 1.013 to 1.095, P=0.009), poorly differentiated adenocarcinoma (HR=7.572, 95%CI: 1.815 to 31.587, P=0.005), tumor deposits (HR=4.711, 95% CI: 1.809 to 12.264, P=0.002), mucinous adenocarcinoma (HR=3.063, 95% CI: 1.003 to 9.354, P=0.049), lymphovascular invasion (HR=2.885, 95% CI: 1.062 to 7.832, P=0.038), and nerve infiltration (HR=6.610, 95% CI: 1.037 to 42.122, P=0.046) were adverse prognostic factors of DFS rate; poorly differentiated adenocarcinoma (HR=12.200, 95% CI: 1.985 to 74.972, P=0.007), tumor nodules (HR=5.379, 95% CI: 1.636 to 17.685, P=0.006), over 70 years of age (HR=1.062, 95% CI: 1.013 to 1.114, P=0.013), and perineural invasion (HR=8.043, 95% CI: 1.026 to 63.055, P=0.047) were adverse prognostic factors of OS rate. There was no significant difference in the 3-year DFS rate and 3-year OS rate between T1-2 group and T3-4 group (P>0.05). Conclusion: Over 70 years of age, poorly differentiated adenocarcinoma, mucinous adenocarcinoma, tumor nodules, lymphovascular invasion, and perineural invasion are independent adverse prognostic factors of lymph node-negative colorectal cancer.

Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW_{th} reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective ^{239}Pu fission fractions F_{239} from 0.25 to 0.35, Daya Bay measures an average IBD yield σ[over ¯]_{f} of (5.90±0.13)×10^{-43}  cm^{2}/fission and a fuel-dependent variation in the IBD yield, dσ_{f}/dF_{239}, of (-1.86±0.18)×10^{-43}  cm^{2}/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the ^{239}Pu fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1σ. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes ^{235}U, ^{239}Pu, ^{238}U, and ^{241}Pu. Based on measured IBD yield variations, yields of (6.17±0.17) and (4.27±0.26)×10^{-43}  cm^{2}/fission have been determined for the two dominant fission parent isotopes ^{235}U and ^{239}Pu. A 7.8% discrepancy between the observed and predicted ^{235}U yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin^{2}2θ_{μe} are set over 6 orders of magnitude in the sterile mass-squared splitting Δm_{41}^{2}. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm_{41}^{2}<0.8  eV^{2} at 95%  CL_{s}.

Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2×10^{-4}≲|Δm_{41}^{2}|≲0.3  eV^{2} mass range. The resulting limits on sin^{2}2θ_{14} are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the |Δm_{41}^{2}|≲0.2  eV^{2} region.

GOLM1 Modulates EGFR/RTK Cell-Surface Recycling to Drive Hepatocellular Carcinoma Metastasis

The mechanism of cancer metastasis remains poorly understood. Using gene profiling of hepatocellular carcinoma (HCC) tissues, we have identified GOLM1 as a leading gene relating to HCC metastasis. GOLM1 expression is correlated with early recurrence, metastasis, and poor survival of HCC patients. Both gain- and loss-of-function studies determine that GOLM1 acts as a key oncogene by promoting HCC growth and metastasis. It selectively interacts with epidermal growth factor receptor (EGFR) and serves as a specific cargo adaptor to assist EGFR/RTK anchoring on the trans-Golgi network (TGN) and recycling back to the plasma membrane, leading to prolonged activation of the downstream kinases. These findings reveal the functional role of GOLM1, a Golgi-related protein, in EGFR/RTK recycling and metastatic progression of HCC.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

New measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

MicroRNA-219-5p functions as a tumor suppressor partially by targeting platelet-derived growth factor receptor alpha in colorectal cancer

Platelet-derived growth factor receptor (PDGFR) signaling pathway was involved in the progress of colorectal cancer (CRC). By using the bioinformatic system online, we found that PDGFRα is a potential target of miR-219-5p. However, the expression pattern and underlying mechanisms of miR-219-5p had not been elucidated in CRC. Herein, we first evaluated the expression of miR-219-5p in tumor tissues by real-time polymerase chain reaction. Next, we confirmed that PDGFRα is the target of miR-219-5p by using luciferase report. And then, we investigated the biological functions of miR-219-5p in vitro in cell proliferation and apoptosis as well as cell cycle by gain and loss of function strategies. Data shown that miR-219-5p is down-regulated in CRC tissues compared with the corresponding matched normal tissues. PDGFRα was a direct target of miR-219-5p. Overexpression of miR-219-5p could inhibit cell proliferation, promote cell apoptosis and induce cell cycle arrest at the G1 phase. Furthermore, miR-219-5p suppressed the activation of the phosphatidylinositol 3-kinase/Akt signaling pathway and downregulated G1 cell-cycle-related protein cyclin D1, cyclin-dependent kinase (CDK) 4, and CDK6. Taken together, our results demonstrate that miR-219-5p functions as a tumor suppressor partially by targeting PDGFRα in colorectal cancer.

Search for a light sterile neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)<|Δm(41)(2) |< 0.3 eV(2) range. The relative spectral distortion due to the disappearance of electron antineutrinos was found to be consistent with that of the three-flavor oscillation model. The derived limits on sin(2) 2θ(14) cover the 10(-3) eV(2) ≲ |Δm(41)(2)| ≲ 0.1 eV(2) region, which was largely unexplored.

A laparoscopic approach to benign retrorectal tumors

BACKGROUND

Retrorectal tumors (RTs) are rare in adults. Their surgical excision is often difficult because of their anatomic location. The aim of this study was to evaluate the results of straight laparoscopic resection of RTs in our institution.

METHODS

Eight patients (six women and two men) with benign RTs were treated by laparoscopic resection in our tertiary care center between September 2012 and June 2013. Exclusion criteria included malignant tumors, lesions with fistula formation, and anterior sacral meningoceles. Clinical data, imaging features, operative details, pathological results, and treatment outcomes were reviewed and analyzed.

RESULTS

Eight cases of benign RT with an average diameter of 8.9 ± 1.7 cm were treated by a straight laparoscopic procedure. The mean operative time was 122 ± 36 min, and the average intraoperative blood loss was 46 ± 33 ml. The median postoperative stay was 5 days (range 3-8 days), and all patients were discharged without serious complications. During a median follow-up of 11 months, no tumor recurrence was observed.

CONCLUSIONS

In our experience, a laparoscopic approach is safe for removing benign tumors in the retrorectal space. This approach may provide access to this difficult-to-reach space and has the advantages of allowing excellent visualization, meticulous dissection, less morbidities, and fast recuperation.

Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay

A measurement of the energy dependence of antineutrino disappearance at the Daya Bay reactor neutrino experiment is reported. Electron antineutrinos (ν¯(e)) from six 2.9  GW(th) reactors were detected with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41 589 (203 809 and 92 912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude sin(2)2θ(13)=0.090(-0.009)(+0.008) and the first direct measurement of the ν¯(e) mass-squared difference |Δm(ee)2|=(2.59(-0.20)(+0.19))×10(-3)  eV2 is obtained using the observed ν¯(e) rates and energy spectra in a three-neutrino framework. This value of |Δm(ee)2| is consistent with |Δm(μμ)2| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.

Observation of electron-antineutrino disappearance at Daya Bay

The Daya Bay Reactor Neutrino Experiment has measured a nonzero value for the neutrino mixing angle θ(13) with a significance of 5.2 standard deviations. Antineutrinos from six 2.9 GWth reactors were detected in six antineutrino detectors deployed in two near (flux-weighted baseline 470 m and 576 m) and one far (1648 m) underground experimental halls. With a 43,000 ton-GWth-day live-time exposure in 55 days, 10,416 (80,376) electron-antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to expected number of antineutrinos at the far hall is R=0.940±0.011(stat.)±0.004(syst.). A rate-only analysis finds sin(2)2θ(13)=0.092±0.016(stat.)±0.005(syst.) in a three-neutrino framework.

Neonatal corticosterone administration impairs adult eyeblink conditioning and decreases glucocorticoid receptor expression in the cerebellar interpositus nucleus

Neonatal maternal separation alters adult learning and memory. Previously, we showed that neonatal separation impaired eyeblink conditioning in adult rats and increased glucocorticoid receptor (GR) expression in the cerebellar interpositus nucleus, a critical site of learning-related plasticity. Daily neonatal separation (1 h/day on postnatal days 2-14) increases neonatal plasma corticosterone levels. Therefore, effects of separation on GR expression in the interpositus and consequently adult eyeblink conditioning may be mediated by neonatal increases in corticosterone. As a first step in exploring a potential role for corticosterone in the neonatal separation effects we observed, we assessed whether systemic daily (postnatal days 2-14) corticosterone injections mimic neonatal separation effects on adult eyeblink conditioning and GR expression in the interpositus. Control uninjected animals were compared to animals receiving either daily corticosterone injections or daily injections of an equal volume of vehicle. Plasma corticosterone values were measured in a separate group of control, neonatally separated, vehicle injected, or corticosterone injected pups. In adulthood, rats underwent surgery for implantation of recording and stimulating electrodes. After recovery from surgery, rats underwent 10 daily sessions of eyeblink conditioning. Then, brains were processed for GR immunohistochemistry and GR expression in the interpositus nucleus was assessed. Vehicle and corticosterone injections both produced much larger increases in neonatal plasma corticosterone than did daily maternal separation, with the largest increases occurring in the corticosterone-injected group. Neonatal corticosterone injections impaired adult eyeblink conditioning and decreased GR expression in the interpositus nucleus, while the effects of vehicle injections were intermediate. Thus, while neonatal injections and maternal separation both produce adult impairments in learning and memory, these manipulations produce opposite changes in GR expression. This suggests an inverted U-shaped relationship may exist between both neonatal corticosterone levels and adult GR expression in the interpositus nucleus, and adult GR expression in the interpositus and eyeblink conditioning.

Chronic stress alters neural activity in medial prefrontal cortex during retrieval of extinction

Chronic restraint stress produces morphological changes in medial prefrontal cortex and disrupts a prefrontally mediated behavior, retrieval of extinction. To assess potential physiological correlates of these alterations, we compared neural activity in infralimbic and prelimbic cortex of unstressed versus stressed rats during fear conditioning and extinction. After implantation of microwire bundles into infralimbic or prelimbic cortex, rats were either unstressed or stressed via placement in a plastic restrainer (3 h/day for 1 week). Rats then underwent fear conditioning and extinction while activity of neurons in infralimbic or prelimbic cortex was recorded. Percent freezing and neural activity were assessed during all phases of training. Chronic stress enhanced freezing during acquisition of conditioned fear, and altered both prelimbic and infralimbic activity during this phase. Stress did not alter initial extinction or conditioned stimulus (CS)-related activity during this phase. However, stress impaired retrieval of extinction assessed 24 h later, and this was accompanied by alterations in neuronal activity in both prelimbic and infralimbic cortex. In prelimbic cortex, unstressed rats showed decreased activity in response to CS presentation, whereas stressed rats showed no change. In infralimbic cortex, neurons in unstressed rats exhibited increased firing in response to the CS, whereas stressed rats showed no increase in infralimbic firing during the tone. Finally, CS-related firing in infralimbic but not prelimbic cortex was correlated with extinction retrieval. Thus, the stress-induced alteration of neuronal activity in infralimbic cortex may be responsible for the stress-induced deficit in retrieval of extinction.

Loss of heterozygosity at D8S298 is a predictor for long-term survival of patients with tumor-node-metastasis stage I of hepatocellular carcinoma

PURPOSE

Our previous studies have shown that chromosome 8p deletion correlates with metastasis of hepatocellular carcinoma (HCC). This study was to determine whether 8p deletion could be used in predicting the prognosis of patients with HCC, particularly in those with early stage of HCC.

EXPERIMENTAL DESIGN

A total of 131 patients with tumor-node-metastasis (TNM) stage I of HCC who underwent curative liver resection were enrolled. Loss of heterozygosity (LOH) was examined using 10 microsatellite markers at chromosome 8p, as well as 14 microsatellites at chromosome 1p, 17p, 4q, 13q, and 16q, and their association with 5-year overall survival (OS) and disease-free survival (DFS) of patients was analyzed.

RESULTS

In the entire cohort of patients, the mean LOH frequency at these 24 loci was 43.2%; LOH frequencies at D8S298 and D1S199 were 31.5% and 33.7%, respectively. LOH at D8S298 was associated with a worse 5-year OS (P = 0.008) and DFS (P = 0.038) in patients with TNM stage I of HCC. Likewise, the patients with LOH at D1S199 had a worse 5-year OS (P < 0.001) and DFS (P = 0.014) compared with those without LOH at D1S199. In multivariate analyses, LOH at D8S298 was an independent predictor of decreased DFS (hazard ratio, 0.372; 95% 95% confidence interval, 0.146-0.948; P = 0.038), whereas LOH at D1S199 was an independent predictor of decreased OS (hazard ratio, 0.281; 95% confidence interval, 0.123-0.643; P = 0.003).

CONCLUSIONS

LOH at D8S298 and D1S199 is independently associated with a worse survival in patients with TNM stage I of HCC after curative resection and could serve as novel prognostic predictors for this subgroup of patients.

[Loss of heterozygosity of plasma circulating DNA from hepatocellular carcinoma patients and its clinical significance]

OBJECTIVES

To detect the loss of heterozygosity (LOH) of circulating DNA in the plasma of patients with hepatocellular carcinoma (HCC), and to assess its potential as a clinical predictive marker.

METHODS

Three high-polymorphic microsatellite markers D8S277, D8S298 and D8S1771 located at chromosome 8p were selected to detect LOH in plasma DNA of 62 HCC patients. The associations between LOH and its clinicopathological features, including HBsAg, liver cirrhosis, serum AFP level, tumor size, tumor cell differentiation, and intrahepatic metastasis were also examined.

RESULTS

In plasma DNA of the 62 HCC patients, LOH was found at one or several loci in 36 (58.1%), and heterozygosity at D8S277, D8S298, and D8S1771 loci was 74.2% (46/62), 75.8% (47/62), and 69.4% (43/62), respectively. LOH frequency at D8S277, D8S298 and D8S1771 was 32.6% (15/46), 44.7% (21/47), and 46.5% (20/43), respectively. LOH in plasma DNA was more frequently detected in the patients with intrahepatic cancer metastasis than those without metastasis (62.5 percent vs. 26.1 percent, P < 0.05); however, no statistically significant correlations were observed between LOH at these loci and other clinicopathological features analyzed in this study.

CONCLUSIONS

LOH at D8S298 in plasma DNA may be a potential predictive marker of intrahepatic metastatic recurrence after surgical resection of the HCC.

Relations of Budd-Chiari syndrome to prothrombin gene mutation

BACKGROUND

Budd-Chiari syndrome (BCS) is a type of disease characterized by portal hypertension and/or hypertension of the inferior vena cava (IVC) due to the obstruction of the hepatic veins (HV) and/or intrahepatic IVC outlet. Being etiologically complicated and obscure, BCS can be acquired or idiopathic and several gene mutations may be contributable. This study was to explore whether prothrombin gene mutation (FII G20210A) takes part in the pathogenesis of BCS and to investigate their correlativity.

METHODS

In 38 proven BCS patients and 70 controls, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to find FII G20210A mutation. To detect whether there are any mutations, four steps were taken: purification of genome DNA from whole blood, amplification of special fragment by polymerase chain reaction, digestion of the fragment via restriction endonuclease, and analysis of results by polyacrylamide gel electrophoresis.

RESULTS

FII G20210A mutation was not detected in all patients and controls.

CONCLUSIONS

No FII G20210A mutation exists in Chinese patients with BCS, nor correlativity between the occurrence of BCS and FII G20210A mutation. The etiology of BCS in the Chinese needs further investigation.

Effect of ionizing radiation on liver mitochondrial respiratory functions in mice

OBJECTIVE

To investigate the radiation effect on mitochondria of the mouse liver in vivo.

METHODS

Livers of BALB/c mice were squeezed out through openings cut on the upper abdomen and radiation doses were delivered only to the livers. Radiation effects on the structure and function of liver mitochondria were evaluated from both respiratory control ratio (RCR) and ADP/O (adenosine 5'-diphosphate/oxygen) ratio supported by two substrates, succinate and glutamate/malate mixtures.

RESULTS

The data showed that both state 3 and state 4 respiratory rates were significantly decreased concomitantly with the increase of radiation dose up to 20 Gy. Succinate-supported, but not glutamate/malate-supported, respiratory control ratio, was also decreased with the increase of radiation dose. ADP/O ratios measured from the support of both succinate and glutamate/malate were not changed by gamma-radiation. This differential radiation damage indicated that respiratory control ratio was more vulnerable to radiation than oxidative phosphorylation.

CONCLUSIONS

Although the functional integrity of ATP synthetic machinery of the mitochondria was not perturbed by ionizing radiation under 20 Gy, the structural integrity of mitochondrial membrane might be affected by ionizing radiation at a dose-dependent manner.