Up-regulation of connexin45 in heart failure

INTRODUCTION: Heart failure is associated with reduced expression of the major gap junction protein connexin43 (Cx43), which may contribute to arrhythmias and sudden cardiac death in this patient population. Other cardiac connexins may be altered as well. Because connexin45 (Cx45) has been shown to colocalize with Cx43, we determined whether the number, size, or distribution of Cx45 gap junctions is altered in the failing heart. METHODS AND RESULTS: Cx45 expression levels were measured by immunoblotting and quantitative immunostaining in failing and control human left ventricles. Total Cx45 protein was significantly (P = 0.021) up-regulated 1.8-fold in failing hearts. Cx45 immunohistochemical signal was increased by 80% (P = 0.005) due to a 3.5-fold increase in the number of gap junctions containing Cx45. Cx45 mRNA was not altered in failing hearts, suggesting reduced degradation of Cx45 protein in the failing heart. Cx43 signal, on the other hand, was reduced by 49% in failing hearts. Double-label experiments demonstrated colocalization of Cx45 and Cx43 in the same gap junctions. CONCLUSION: Cx45 is markedly enhanced in the failing heart. Up-regulation of Cx45 in conjunction with down-regulation of Cx43 could result in abnormal impulse propagation and generation of ventricular arrhythmias, thereby predisposing patients in heart failure to sudden cardiac death.     

常规QA设备对脊柱转移瘤SRS/SBRT计划的验证及存在问题探讨

目的:对比aSi-1200 EPID与Octavius 1500电离室矩阵在6 MV非均整脊柱转移瘤计划验证中的应用,探讨可能存在的问题。方法:23例计划在全局归一方式下以不同标准和阈值行2D γ通过率（GPR）评估,将治疗计划系统（TPS）中患者数据导入Verisoft软件重建剂量。引入不同类型和量值的误差:MLC的透射率（TF）和剂量叶片间隙（DLG）、治疗等中心和MU误差,使用GPR方法量化Octavius 1500识别这些误差的灵敏度,并通过评估靶区和危及器官（OARs）剂量学指标变化研究TF和DLG误差的临床意义。结果:与Octavius 1500矩阵相比,EPID方式在同一标准不同阈值下GPR均值更大数据离散程度更小,重建与计算的剂量体积直方图分析表明临床靶区和计划靶区Dmin、Dmax和Dmean的百分剂量偏差（DD%）较大,其中临床靶区最大DD%值为50.00%、11.31%和-8.71%,计划靶区最大DD%值为-25.86%、9.31%和-8.22%。治疗等中心和+3%、+5%的MU误差都被检测到,所有标准均未检测到TF误差,+0.3 mm的DLG误差只被2%/3 mm的标准检测到。TF值增大0.023 6％模型误差和DLG增加0.3 mm模型误差均导致靶区和OARs的剂量增加,其中OARs剂量增加较明显,尤其健侧肺的V20分别增加9.80%和8.85%,脊髓D0.1 cc均增加5.35%。结论:使用GPR方法识别引入误差的MLC模型可靠性不够,提示鉴别TPS问题的根源需要更有效的独立质量保证方法以确保通过TPS计算得出的陡峭剂量梯度的可信度。剂量验证系统软件算法的独立验证研究是有必要的,以确定算法局限性导致的重建剂量不确定性范围。     

Effects of Deposition and Annealing Temperature on the Structure and Optical Band Gap of MoS2 Films

In this study, molybdenum disulfide (MoS₂) film samples were prepared at different temperatures and annealed through magnetron sputtering technology. The surface morphology, crystal structure, bonding structure, and optical properties of the samples were characterized and analyzed. The surface of the MoS₂ films prepared by radio frequency magnetron sputtering is tightly coupled and well crystallized, the density of the films decreases, and their voids and grain size increase with the increase in deposition temperature. The higher the deposition temperature is, the more stable the MoS₂ films deposited will be, and the 200 °C deposition temperature is an inflection point of the film stability. Annealing temperature affects the structure of the films, which is mainly related to sulfur and the growth mechanism of the films. Further research shows that the optical band gaps of the films deposited at different temperatures range from 0.92 eV to 1.15 eV, showing semiconductor bandgap characteristics. The optical band gap of the films deposited at 200 °C is slightly reduced after annealing in the range of 0.71–0.91 eV. After annealing, the optical band gap of the films decreases because of the two exciton peaks generated by the K point in the Brillouin zone of MoS₂. The blue shift of the K point in the Brillouin zone causes a certain change in the optical band gap of the films.     

关于急性心肌梗死早期阴离子间隙的研究

目的:探讨急性心肌梗死（AMI）与阴离子间隙（AG）的关系。方法:对352例AMI患者和268例不稳定型心绞痛（UA）患者进行回顾性分析。比较两组初始AG的差异;将AMI组按左室射血分数（LVEF）水平分为射血分数减低的心力衰竭（HFrEF）,射血分数中间值的心力衰竭（HFmrEF）和射血分数保留的心力衰竭（HFpEF）3个亚组,观察AG与AMI患者院内心力衰竭程度的关系。结果:与UA组相比,AMI组AG明显升高（P＜0.001）,二氧化碳结合力（CO2CP）明显降低（P＜0.001）。AMI亚组分析发现初始AG水平与院内心力衰竭程度呈正相关,组间比较均有统计学差异（P＜0.05）。Logistic回归分析表明,AMI院内心力衰竭程度与初始AG水平有关（OR=1.156,P=0.004,95%CI:1.047~1.275）。结论:初始AG水平可作为AMI的临床状态和危重度的评估,也是AMI患者发生心功能损害轻重的独立预测因子。     

缝隙连接在血管内皮和平滑肌细胞中的作用及其与高血压的关系

细胞间的直接通讯--缝隙连接在控制和协调血管功能方面起重要作用。缝隙连接是沟通相邻细胞质膜的唯一一类通道,为离子、小分子代谢物质、第二信使等细胞间信号分子的直接交换提供一个通道。血管内皮细胞和平滑肌细胞表达多种类型缝隙连接蛋白(connexin,Cx),多种Cx 在心血管系统中的共同表达并协调一致地工作,对心血管系统的发育、平滑肌和内皮细胞功能的整合、以及对血管壁细胞功能协调等起着重要作用。在血管发生疾病时Cx表达相应发生改变,以与缝隙连接调节血管紧张度和动脉血压的作用相一致。本综述讨论了在血管内皮和平滑肌细胞在生理和病理情况下(以高血压为例)缝隙连接对血管结构和功能的影响。     

Intramural injection with botulinum toxin significantly elongates the pig esophagus

Background/Purpose

Surgical treatment of long-gap esophageal atresia (LGEA) is challenging. Methods which facilitate stretching of the esophageal pouches may allow primary anastomosis. Botulinum toxin type A (BTX-A) blocks acetylcholine release in neuromuscular junctions, thereby causing muscle relaxation. We hypothesized that intramural injections with BTX-A into the esophageal wall of piglets would significantly elongate the tissue upon stretch.

Methods

Twenty-four piglets were randomized to receive BTX-A of placebo (saline). After one hour, the esophagus was removed en bloc and tested in a stretch-tension device.

Results

The mean esophageal elongation was 84% (range 83–101) in the BTX-A-group and 65% (50–78) in the control group. The mean difference between the two groups was 18%, which was significant (p < 0.001).

Conclusion

Intramural injections with botulinum toxin type A elongate the esophagus significantly. Clinically, this could be a potential method to achieve primary anastomosis in LGEA. Additional clinical studies are necessary to evaluate the method before it can be generally recommended.     

Posterior Femoral Condylar Offset After Total Knee Replacement in The Risk of Knee Flexion Contracture

The aim of this study was to clarify the risk of knee flexion contracture associated with a posterior femoral condylar offset after total knee replacement (TKR). Radiographs from 100 healthy Japanese volunteers were included in the study. We evaluated femoral component posterior offset in various implants and compared them with the normal Japanese knee. Posterior offset of the femoral condyle is up to a maximum of 4.7 times greater than that of the healthy Japanese knee in all knee implants. Excess posterior offset of the femoral condyle in TKR prostheses may cause knee joint flexion contracture due to the relative shortening of the posterior soft tissue.