[Clinical experience of minimal invasive coronary surgery-coronary artery bypass grafting: a series of 244 cases]

Objective: To examine the safety and efficacy of minimally invasive coronary surgery-coronary artery bypass grafting (MICS-CABG). Methods: From the first case in November 2015 to November 2019, a total of 244 cases of MICS-CABG were performed in Department of Cardiovascular Surgery, Peking University Third Hospital. There were 197 males and 47 females, aging (62.3±8.7)years (range: 36 to 88 years). The operations were performed via the 5(th) intercostal space of left thoracic lateral incision (length: 4 to 5 cm extended for 8 to 10 cm), and were performed under off-pump, with the help of the chest wall suspension device and cardiac fixator. The proximal anastomosis on ascending aorta and the distal anastomosis of left anterior descending branch, circumflex branch and right coronary system were completed according to procedure. In all 244 cases, the proportion of 2 grafts was 53.7% (131 cases), 3 grafts was 36.1% (88 cases), 4 grafts was 9.8% (24 cases) and 5 grafts was 0.4% (1 case). The average of grafts was 2.6±0.7 (range: 2 to 5). The proportion of hybrid was 14.3% (35 cases), sequential bypass procedure was 43.0% (105 cases) and multiple artery grafts was 25.4% (62 cases). The perioperative complications of the patients were collected, the patency rate of the grafts was evaluated by coronary angiography or CT within 7 days after the operation, and main adverse cardiovascular and cerebrovascular events (MACCE) were followed up. The survival curve was drawn by Kaplan-Meier method, and the 1-year MACCE rate was calculated by survival analysis. Results: All cases had no transition to thoracotomy and cardiopulmonary bypass procedure, and no cases needed intra aortic balloon pumping and extracorporeal membrane oxygenation during the operation.There were 2 cases of poor incision healing, and reoperation was performed in 10 cases (6 cases of postoperative bleeding, 2 cases of incision debridement, and 2 cases of grafts problems). The rate of MACCE in 30 days was 2.6% (10 cases), which contained 3 cases of death (2 cases of grafts occlusion, 1 case of serious hemorrhage after thoracic puncture drainage), 3 cases of stroke and 5 cases of non-fatal myocardial infarction. By the re-examination of angiography in 7 days after operation, the overall patency of the grafts was 96.1%, and the patency of the left anterior descending was 98.6%. Kaplan-Meier survival analysis was conducted for 235 patients (96.3%) with 1 to 36 months follow-up results, and the 1-year MACCE rate was 5.6% (95%CI: 4.2% to 7.0%) . There was no significant difference among the incidences of MACCE at each stage of learning curve. Surgeon could reduce the operation time and complete more anastomosis with the accumulation of experience after the early 30 cases. Conclusions: MICS-CABG can safely achieve completed revascularization, which has good operative effects in short and medium-long term. There is no significant risk in the early cases of learning curve.

The role of miR-145 in promoting the fibrosis of pulmonary fibroblasts

The effects of miR-145 (microRNA 145) on M. pneumoniae (MP)-infected MRC-5 (Medical Research Council cell strain 5) cell TGF-β/Smad (transforming growth factor beta/Smad) fibrosis pathway were explored through constructing MP-infected MRC-5 cell models. In addition, the qPCR (quantitative real-time polymerase chain reaction) and Western blot were applied to detect the mRNA and protein expressions of miR-145, TGF-β1 (transforming growth factor beta 1), Smad3, Smad4, MMP2 (matrix metalloproteinase 2), FN1 (fibronectin 1), ELN (elastin) and COLI α1 (collagen type I alpha 1) signaling molecules in TGF-β/Smad fibrosis pathway. The results showed that the expression of miR-145 in MRC-5 cells was significantly increased after MP infection. In addition, miR-145 inhibited the fibrosis promoting TGF-β/Smad pathway by targeting Smad3, a key factor in the TGF-β/Smad pathway. It can be concluded that, in the process of MP infection, the expression of miR-145 is stimulated to negatively regulate the fibrosis-promoting pathway of TGF-β/Smad.

[Early clinical outcomes of minimally invasive coronary surgery-total arterial coronary revascularization]

Objective: To summarize the early experience and clinical value of minimally invasive coronary surgery-total arterial coronary revascularization (MICS-TACR) through the left anterior small incision. Methods: Between May 2015 and June 2018, a total of 31 consecutive cases [21 males and 10 females, aged (63.2±9.3) years] in Peking University Third Hospital who were performed MICS-TACR with bilateral internal mammary artery and radial artery were enrolled. Meanwhile, 1 489 cases of conventional median sternal incision off-pump coronary artery bypass grafting (OPCABG) were matched as control group. According to exclusion criteria and matching score, 90 cases [55 males and 35 females, aged (63.8±9.5) years] were selected as the control group, and the perioperative data of the two groups were compared. All patients in MICS-TACR group underwent postoperative angiography and the graft patency was evaluated. Results: There were no statistically significant differences in baseline data between the two groups. The perioperative blood transfusion of MICS-TACR group was less than control group [0(0,0) U vs 0(0,4) U, P=0.003]. There were no statistically significant differences in operative mortality, intraoperative and postoperative intra-aortic balloon pump (IABP) and extracorporeal membrane oxygenation (ECMO) use, re-operation rate, perioperative major adverse cardiac and cerebrovascular events (MACCE), new-onset renal failure, atrial fibrillation, and multiple organ failure between the two groups. Postoperative angiography showed that there was no significant difference in the patency rate between the MICS-TACR group and control group(all P>0.05). Conclusion: Total arterial coronary revascularization can be successfully accomplished under the left anterior small incision, and the early clinical outcome is satisfied.

Online monitoring of oil film using electrical capacitance tomography and level set method

In the application of oil-air lubrication system, electrical capacitance tomography (ECT) provides a promising way for monitoring oil film in the pipelines by reconstructing cross sectional oil distributions in real time. While in the case of small diameter pipe and thin oil film, the thickness of the oil film is hard to be observed visually since the interface of oil and air is not obvious in the reconstructed images. And the existence of artifacts in the reconstructions has seriously influenced the effectiveness of image segmentation techniques such as level set method. Besides, level set method is also unavailable for online monitoring due to its low computation speed. To address these problems, a modified level set method is developed: a distance regularized level set evolution formulation is extended to image two-phase flow online using an ECT system, a narrowband image filter is defined to eliminate the influence of artifacts, and considering the continuity of the oil distribution variation, the detected oil-air interface of a former image can be used as the initial contour for the detection of the subsequent frame; thus, the propagation from the initial contour to the boundary can be greatly accelerated, making it possible for real time tracking. To testify the feasibility of the proposed method, an oil-air lubrication facility with 4 mm inner diameter pipe is measured in normal operation using an 8-electrode ECT system. Both simulation and experiment results indicate that the modified level set method is capable of visualizing the oil-air interface accurately online.

Design of the radiation shielding for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

A radiation shielding has been designed to reduce scattered neutrons and background gamma-rays for the new double-ring Time Of Flight Enhanced Diagnostics (TOFED). The shielding was designed based on simulation with the Monte Carlo code MCNP5. Dedicated model of the EAST tokamak has been developed together with the emission neutron source profile and spectrum; the latter were simulated with the Nubeam and GENESIS codes. Significant reduction of background radiation at the detector can be achieved and this satisfies the requirement of TOFED. The intensities of the scattered and direct neutrons in the line of sight of the TOFED neutron spectrometer at EAST are studied for future data interpretation.

Light output function and assembly of the time-of-flight enhanced diagnostics neutron spectrometer plastic scintillators for background reduction by double kinematic selection at EAST

The 2.5 MeV neutron spectrometer TOFED (Time-Of-Flight Enhanced Diagnostics) has been constructed to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas on EAST. The instrument has a double-ring structure which, in combination with pulse shape digitization, allows for a dual kinematic selection in the time-of-flight/recoil proton energy (tof/Ep) space, thus improving the spectrometer capability to resolve fast ion signatures in the neutron spectrum, in principle up to a factor ≈100. The identification and separation of features from the energetic ions in the neutron spectrum depends on the detailed knowledge of the instrument response function, both in terms of the light output function of the scintillators and the effect of undesired multiple neutron scatterings in the instrument. This work presents the determination of the light output function of the TOFED plastic scintillator detectors and their geometrical assembly. Results from dedicated experiments with γ-ray sources and quasi-monoenergetic neutron beams are presented. Implications on the instrument capability to perform background suppression based on double kinematic selection are discussed.

Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G.

Data acquisition system with pulse height capability for the TOFED time-of-flight neutron spectrometer

A new time-of-flight neutron spectrometer TOFED has been constructed for installation at Experimental Advanced Superconducting Tokamak. A data acquisition system combining measurements of flight time and energy from the interaction of neutrons with the TOFED scintillators has been developed. The data acquisition system can provide a digitizing resolution better than 1.5% (to be compared with the >10% resolution of the recoil particle energy in the plastic scintillators) and a time resolution <1 ns. At the same time, it is compatible with high count rate event recording, which is an essential feature to investigate phenomena occurring on time scales faster than the slowing down time (≈100 ms) of the beam ions in the plasma. Implications of these results on the TOFED capability to resolve fast ion signatures in the neutron spectrum from EAST plasmas are discussed.

Monte Carlo simulation of a Bonner sphere spectrometer for application to the determination of neutron field in the Experimental Advanced Superconducting Tokamak experimental hall

To assess the neutron energy spectra and the neutron dose for different positions around the Experimental Advanced Superconducting Tokamak (EAST) device, a Bonner Sphere Spectrometer (BSS) was developed at Peking University, with totally nine polyethylene spheres and a SP9 (3)He counter. The response functions of the BSS were calculated by the Monte Carlo codes MCNP and GEANT4 with dedicated models, and good agreement was found between these two codes. A feasibility study was carried out with a simulated neutron energy spectrum around EAST, and the simulated "experimental" result of each sphere was obtained by calculating the response with MCNP, which used the simulated neutron energy spectrum as the input spectrum. With the deconvolution of the "experimental" measurement, the neutron energy spectrum was retrieved and compared with the preset one. Good consistence was found which offers confidence for the application of the BSS system for dose and spectrum measurements around a fusion device.

[The protective effects of tea catechins on the injury of cerebral ischemia and reperfusion in rats]

OBJECT

The protective effects of tea catechins on the injury of cerebral ischemia and reperfusion in rats were observed with rat cerebral ischemia and reperfusion model produced by bilaterally clamping the common carotid arteries and vagus nerves for 60 min and then removing the occlusion for 30 min.

METHOD

Wistar rats were divided into normal control group, model group and catechin group (30 mg.kg-1 and 50 mg.kg-1 i.p., qd x 7 d). The changes of biochemical indications and pathology were observed.

RESULT

The results presented that the concentration of MDA in brain tissue and serum of model rats were higher than that of control rats(P < 0.01). Compared with model group, tea catechin groups could decrease the concentration of MDA in brain tissue and serum, and tea catechin group (50 mg.kg-1 i.p., qd x 7 d) could improve the injury of blood brain barrier.

CONCLUSION

Tea catechins have protective effects on the injury of cerebral ischemia and reperfusion in rats.

[Prophylactic and therapeutic effect of jiawei zhigancao tang injection on experimental arrhythmia in rats]

The antiarrhythmic effect of Jiawei Zhigancao Tang injection (JZTI) was studied in experimental arrhythmia induced by aconitine or by CaCl2 in anesthetized rats. The prophylactic dose of JZTI (5g/kg, i.v.) reduced the incidence rate of premature ventricular complexes, ventricular tachycardia (P < 0.01), delayed the onset time of arrhythmia induced by CaCl2 (P < 0.01), and the recovery time of sinus rhythm occurred earlier than that of control group (P < 0.01). The therapeutic dose of JZTI (10g/kg, i.v.) raised the rate of aconitine-induced arrhythmia to sinus rhythm conversion (P < 0.05). The results showed that JZTI could significantly antagonize arrhythmia induced by aconitine or by Cacl2 in rats.