[Pre-clinical in vivo evaluation study on a new Chinese-made surgical biopatch for atrial septum].

Objective: To evaluate the safety and effectiveness of a new Chinese-made surgical biopatch for atrial septum under the establishment of atrial septal defect animal model in miniature pigs. Methods: From June 2018 to April 2019, 26 pigs were divided into experimental group (15 pigs) and the control group (11 pigs). Animal models of atrial septal defect were established by traditional surgical methods. The to-be-evaluated and listed surgical biological patches (with a diameter of 10 mm) were implanted in the experimental group and the control group to repair the atrial septal defect. Cardiac ultrasound and blood examination of all animals were performed before and at 7, 30, 90, 180 days after operation, the results were analyzed with repetitive measurement and analysis of variance. At 90 days and 180 days after the operation, tissue samples were taken from animals after euthanasia. Pathological examination of heart and major organs were conducted. The independent sample t test and rank sum test were used to compare the data between the two groups, and the nonparametric was used to compare the patch calcification score between the two groups. Results: In total of 26 animals, 14 animals in the experimental group(6 at 90 days, 8 at 180 days) and 9 animals in the control group(4 at 90 days, 5 at 180 days) reached the end of the experiment. The other 3 animals (1 in the experimental group and 2 in the control group) died of arrhythmia, whole heart failure and right heart failure, the results of pathological examination showed that the causes of death were unrelated to the experimental materials. Cardiac ultrasound showed no patch leakage in all animals. There was no statistically significant difference in cardiac ultrasound and blood examination between the two groups at different time points after operation (all P>0.05). The pathological results showed that all the implants were intact and had good biocompatibility. There was no significant difference in the mean endothelialization rate between the experimental group and the control group at 90 and 180 days after operation ((80.8±29.1)% vs. (82.5±23.6)%, t=0.095, P=0.927; (78.8±36.4)% vs. (82.0±19.2)%, t=0.182, P=0.859) on 90 and 180 days, there was no significant difference in the patch calcification score between the two groups (1.00(1.25) vs. 2.00(0.75), Z=6.500, P=0.214; 0(0.75) vs. 1.00(2.00), Z=12.000, P=0.139). Conclusion: The new Chinese-made surgical biopatch for atrial septum has comparable safety and efficacy to that of the marketable patch in miniature pig atrial septal defect animal model.

[Treatment efficiency evaluation of left cardiac sympathetic denervation for patients with inherited arrhythmia by exercise-stress test].

Objective: To evaluate the efficiency of left cardiac sympathetic denervation (LCSD) in inherited arrhythmia patients with adrenergic activity-induced malignant ventricular arrhythmia, and observe exercise-stress test features before and after LCSD. Methods: This retrospective observational study included catecholaminergic polymorphic ventricular tachycardia(CPVT) and long QT syndromes(LQTS) patients who underwent video-assisted LCSD at Beijing Tsinghua Changgung Hospital and Peking University People's Hospital from September 2006 to May 2020. The indications for LCSD surgery were intolerant or refractory to beta-blocker medication. Clinical and exercise-stress tests data of included patients were collected before and 1 month after LCSD. Heart rate, exercise tolerance, atrial and ventricular arrhythmia, QTc interval and predictors for sudden cardiac death were analyzed. Patents were regularly followed up at 1, 3, 6, and 12 months after LCSD and then once every year thereafter. Cardiac events and medication adjustment records were collected. Results: Five patients (2 CPVT, 1 LQT1, and 2 LQT2)were included in the study. All patients experienced syncope as first symptom at the median age of 12(10, 16)years, and underwent LCSD at the median age of 21(16, 26)years, Baseline heart rate was similar before and after LCSD ((65.6±6.5) beats/min vs. (68.0±11.1) beats/min, P=0.57); while maximum workload tended to be lower after LCSD ((12.1±2.8) metabolic equivalents (METS) before surgery vs. (10.5±2.4) METS after surgery, P=0.07). Incidence of atrial and ventricular arrhythmia were significantly reduced post LCSD, and the ventricular arrhythmia score was decreased after LCSD in CPVT patients (4 points before LCSD vs. 3 points after LCSD in case 1;5 points before LCSD vs. 3 points after LCSD in case 2). QTc interval was shortened significantly in three LQTs patients (QTc interval at baseline heart rate: (546.6±72.3) ms before surgery vs. (493±61.1) ms after LCSD, P=0.047; QTc interval at maximal exercise heart rate: (516.3±73.7) ms before surgery vs. (486.7±64.2)ms after LCSD, P=0.035). Additionally, sudden cardiac death risk indicator ΔHRR1 (heart rate decreasing value within the first 1 min during recovery phase) decreased from (51.5±21.1) beats/min before surgery to (32.0±13.9) beats/min after surgery (P=0.035). During a median follow-up of 1(1, 4) year, all five patients were on low dosage of propranolol (37.0±21.7) mg/d. Cardiac events free survival was achieved in four out of 5 patients (80%) after sympathectomy, while 1 case suffered from sudden cardiac death after emotional stress. Conclusion: LCSD surgery can be safely and effectively performed in most hereditary arrhythmia patients with adrenergic activity-induced life-threatening cardiac events. Exercise stress test results show that LCSD could reduce malignant arrhythmias and improve sudden cardiac death risk indicators without decreasing heart rate.

[Application of pump-controlled retrograde trial off in weaning from veno-arterial extracorporeal membrane oxygenation in adult patients].

Objective: To Summarize the experience of pump-controlled retrograde trial off (PCRTO) in the process of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) withdrawal in adult patients. Methods: Adult patients who received ECMO assistance in Intensive Care Unit for Cardiac Surgery from March to July 2019 were collected. According to our strategies, PCRTO was used if the patients can wean from VA-ECMO and hemodynamic indexes were recorded during the process. The statistics data was collected, including the 48 hours survival rate, ECMO re-assistance rate, thrombus complications, Intensive Care Unit (ICU) stay time and hospital stay time after weaning from VA-ECMO. The patients who failed in the test were continued to be assisted by ECMO. Results: There were 46 patients assisted by VA-ECMO in our center. In total, 21 adults who met the offline test standard underwent 26 PCRTOs, including 10 male adults (47.6%), with an age of 65 (55, 68) years old. Eighteen adults passed the withdrawal test. No new thrombus was found in the arteriovenous ultrasound of the lower extremity after weaning from ECMO, and no pulmonary embolism was found in the chest X-ray. The success rate of weaning from ECMO was 69.23%(18/26). The D-dimer decreased [584(348,2 107)µg/L vs 1 440(631,2 916)µg/L, P=0.014] and the left ventricular ejection fraction (LVEF) increased (51.4%±8.5% vs 46.9%±10.6%, P=0.013) on the next day after weaning. There were significant differences in heart rate (HR), central venous pressure (CVP), oxygenation index and lactate (Lac) during the PCRTO in the group which involved the cases of the 8 failed experiments (all P<0.05). Compared with the failure group, there were significant differences in age, blood flow rate, CVP before the test, HR, pulse oxygen saturation(SpO(2)), CVP, Lac and oxygenation index after the test, and the variations of SpO(2), CVP and Lac. Conclusion: PCRTO is a simple, reversible, safe and effective weaning method. It can be used in the process of VA-ECMO withdrawal in adult patients.

Transgenic rice expressing a cassava (Manihot esculenta Crantz) plasma membrane gene MePMP3-2 exhibits enhanced tolerance to salt and drought stresses.

Plasma membrane proteolipid 3 (PMP3) is a class of small hydrophobic proteins found in many organisms including higher plants. Some plant PMP3 genes have been shown to respond to abiotic stresses and to participate in the processes of plant stress tolerance. In this study, we isolated the cassava (Manihot esculenta Crantz) MePMP3-2 gene and functionally characterized its role in tolerance to abiotic stress by expressing it in rice (Oryza sativa L.). MePMP3-2 encodes a 77-amino acid protein belonging to a subgroup of plant PMP3s that have long hydrophylic C-terminal tails of unknown function. In silico analysis and co-localization studies indicated that MePMP3-2 is a plasma membrane protein with two transmembrane domains, similar to other PMP3s. In cassava leaves, MePMP3-2 expression was up-regulated by salt and drought stresses. Heterologous constitutive expression of MePMP3-2 in rice did not alter plant growth and development but increased tolerance to salt and drought stresses. In addition, under stress conditions MePMP3-2 transgenic plants accumulated less malondialdehyde, had increased levels of proline, and exhibited greater up-regulation of the stress-related genes OsProT and OsP5CS, but led to only minor changes in OsDREB2A and OsLEA3 expression. These findings indicate that MePMP3-2 may play an important role in salt and drought stress tolerance in transgenic rice.

[Research progress of sexual dysfunction following rectal cancer surgery].

Sexual dysfunction with the incidence of 5%-90% is a common postoperative complication of rectal cancer and the ratio of men and women is similar. Sexual function is innervated by the abdominal-pelvic autonomic nerve. Different sexual dysfunctions can be caused by different parts and degrees of injury in autonomic nerve during operations of rectal cancer. With the development of pelvic autonomic nerves preservation in rectal cancer radical resection, postoperative sexual function can be protected. There may be many factors increasing the incidence of postoperative sexual dysfunction in rectal cancer, such as postoperative psychological factors, stoma, abdominal-perineal resection and radiotherapy. The effects of laparoscopic surgery, robotic surgery, transanal total mesorectal excision and lateral lymph node dissection on postoperative sexual function remain controversial. Based on the multidisciplinary cooperation model, attention should be paid to psychological intervention of patients and their partners. In clinical practice, for male using phosphodiesterase-5 inhibitors, vacuum erectile devices, injection of vasodilators through the penis or urethra, and for female local application of estrogen and lubricants in the vagina are effective treatment for postoperative sexual dysfunction of rectal cancer. In addition, stem cell therapy has a promising prospect for sexual dysfunction.

[Immunofluorescent localization of associated antigen of anti-human nasopharyngeal carcinoma cell monoclonal antibody].

The immunofluorescent localization of associated antigen of anti-human nasopharyngeal carcinoma (NPC) cell monoclonal antibody (McAb) was performed in different tissues (NPC, non-NPC tumor, chronic inflammation of nasopharyngeal mucosa, adult normal tissue and embryo tissue) with 5 control experiments. McAb (CN-1, Cs-C1) was produced by Department of Microbiology of our college and all the specimens were confirmed by pathology. The results revealed that Cs-C1 antigen was mainly found on the surface of NPC cells with a positive rate of 80.3%. Majority of the positive cells showed yellow-greenish linear fluorescence surrounding the cell membrane while some cells manifested granular fluorescence. In addition, Cs-C1 antigen was also found in a few embryo tissues, epithelial cells of the normal gastric mucosa and cells of the gastric cancer. It is suggested that Cs-C1 antigen be a kind of molecular structure, being gradually produced or increased in quantity during carcinogenesis, and belong to the tumor associated antigen. Cs-C1 antigen could be important in the study of carcinogenic mechanism of NPC cells and valuable to clinical immunodiagnosis.

[Investigation on the changing regularity of the relationship between retention index and temperature of the GDX series stationary phases].

A systematical measure of the polarity scale of the Chinese porous polymer beads of this series of stationary phase has been carried out, including the McReynolds constant at 120 degrees C by using squalane as non-polar stationary phase and the relative constant to GDX-103 at 180 degrees C. Based on the above work, two kinds stationary phases GDX-101 and GDX-103 were selected, on which the changing regularity of the relationship between retention index and temperature of the five "probes" of stationary polarity determination, including benzene, butanol, 1-nitropropane, 2-pentanone and pyridine were investigated. At the same time, the changing regularity with temperature of the relative McReynolds constant delta I of GDX-101 to GDX-103 was studied. It is found that Ip-theta c curve and delta I-theta c curve all showed a turning point at the temperature of 180 degrees C and that there was a maximum value of delta I at the temperature of 180 degrees C. So we think that the retention mechanism of this kind of stationary phase changed at 180 degrees C.

A vascular endothelial cell antigen with restricted distribution in human foetal, adult and malignant tissues.

Human vascular endothelial cells were isolated by collagenase digestion of umbilical veins. Hybridomas secreting monoclonal antibodies were raised by fusing a mouse myeloma cell line to spleen cells from mice immunized with the isolated endothelial cells. A clone was selected which produced an antibody binding strongly to human umbilical vein endothelial cells. This antibody, EN 3, was shown to be directed against a major antigen on the surface of the cells, and appeared to be distinct from other antigens previously described on vascular tissues. The antibody bound to a lesser extent to umbilical artery endothelial cells and syncytiotrophoblast. Capillary endothelial cells in adult oesophageal tissues and tonsil were also labelled by the antibody, as were capillaries in a seminoma and infiltrating duct carcinoma of the breast. This well defined distribution in some foetal, adult and malignant tissues suggests that there is structural heterogeneity amongst endothelial cells in different sites, which may be linked to differences in differentiation or function.