Efficacy of Arthroscopy-Assisted Minimally Invasive Surgery in the Treatment of Patients with Tibial Plateau Fractures.

Objective: This study analyzes the therapeutic effect of arthroscopy-assisted minimally invasive surgery in patients with tibial plateau fractures (TPFs) and its influence on knee function and range of motion (ROM) recovery. Methods: This study enrolled 84 patients with TPFs admitted to the researchers' hospital between March 2021 and May 2022 as the study subjects, including 42 patients treated with open reduction and internal fixation (observation group) and 42 patients treated with arthroscopy-assisted minimally invasive surgery (experimental group). Then, perioperative indexes, knee symptom scores, knee function scores, knee ROM, and postoperative complications were compared between these two groups. Results: Surgery time was significantly shorter, intraoperative bleeding was less, and the time of the first off-bed activity was signally earlier in the experimental group than in the observation group (P < .05). All postoperative Lysholm and Rasmussen scores in both groups increased compared with preoperative scores, and the degree of increase was higher in the experimental group than in the observation group (P < .05). The range of flexion, extension, and internal/external rotation angles of patients was more extensive in both groups after surgery than before surgery, and the improvement of the experimental group was greater than that of the observation group (P < .05). The experimental group had a considerably lower incidence of postoperative complications than the observation group (P < .05). Conclusion: Arthroscopy-assisted minimally invasive surgery is highly effective in treating TPFs. Specifically, this surgery further improves knee symptoms, promotes the recovery of knee function, elevates knee ROM, and reduces the risk of postoperative complications compared to traditional open reduction and internal fixation.

Ahf-Caltide, a Novel Polypeptide Derived from Calpastatin, Protects against Oxidative Stress Injury by Stabilizing the Expression of CaV1.2 Calcium Channel.

Reperfusion after ischemia would cause massive myocardial injury, which leads to oxidative stress (OS). Calcium homeostasis imbalance plays an essential role in myocardial OS injury. CaV1.2 calcium channel mediates calcium influx into cardiomyocytes, and its activity is modulated by a region of calpastatin (CAST) domain L, CSL54-64. In this study, the effect of Ahf-caltide, derived from CSL54-64, on myocardial OS injury was investigated. Ahf-caltide decreased the levels of LDH, MDA and ROS and increased heart rate, coronary flow, cell survival and SOD activity during OS. In addition, Ahf-caltide permeated into H9c2 cells and increased CaV1.2, CaVß2 and CAST levels by inhibiting protein degradation. At different Ca2+ concentrations (25 nM, 10 µM, 1 mM), the binding of CSL to the IQ motif in the C terminus of the CaV1.2 channel was increased in a H2O2 concentration-dependent manner. CSL54-64 was predicted to be responsible for the binding of CSL to CaV1.2. In conclusion, Ahf-caltide exerted a cardioprotective effect on myocardial OS injury by stabilizing CaV1.2 protein expression. Our study, for the first time, proposed that restoring calcium homeostasis by targeting the CaV1.2 calcium channel and its regulating factor CAST could be a novel treatment for myocardial OS injury.

Binding characteristics of calpastatin domain L to NaV1.5 sodium channel and its IQ motif mutants.

NaV1.5 channel is an integral membrane protein involved in the initiation and conduction of action potentials. IQ motif is located in the C-terminal domain of NaV1.5 sodium channel, which is highly conserved in human sodium channel subtypes. IQ motif is involved in the Ca2+-dependent regulation through interaction with the regulatory proteins such as calpastatin domain L (CSL). Mutations in SCN5A, the gene encoding NaV1.5 channel, have been linked to many cardiac arrhythmias, such as Long QT syndrome type 3 (LQT3) and Brugada syndrome (BRS). LQT3-associated mutations in NaV1.5 IQ motif, IQQ1909R and IQR1913H, have been reported to affect the late INa. A BRS-associated mutation in NaV1.5 IQ motif, IQA1924T, has been reported to affect the peak INa. But the detailed pathogenic mechanisms of LQT3 and BRS remains unclear. To explore the binding properties of CSL to IQ motif and its muants associated with LQT3/BRS, molecular docking and GST pull down assay were performed in this study. As a result, S58 and E59 in CSL activating channel effect region L54-64 were involved in the conformation of the CSL/IQWT complex by protein-protein docking. IQ motif could bind to CSL in a [CSL]-dependent and [Ca2+]-dependent manner by pull down assay. However, the binding affinities of IQQ1909R and IQR1913H to CSL were decreased and its reaction rates with CSL were slower. The binding characteristics of IQA1924T to CSL was opposite in a [Ca2+]-dependent manner and its binding efficacy became smaller. The changes of the binding characteristics of IQmutants to CSL would affect the regulation of NaV1.5 channel, which may be related to LQT3 and BRS.

A Highly Accurate Positioning Solution for C-V2X Systems.

Cellular vehicle-to-everything (C-V2X) is essential in enabling safe, reliable, and efficient transportation services. It serves as serve as the foundation for vehicles to communicate with each other and everything around them. One fundamental element in C-V2X is positioning, namely extracting the vehicle's absolute and relative positions concerning other objects such as buildings, pedestrians, traffic signs, and other vehicles. However, its feasibility in enabling vehicular positioning has not been fully explored yet. In this paper, key performance indicators (KPIs) for C-V2X positioning have been described firstly. Then positioning challenges and conventional positioning methods for C-V2X are reviewed. Afterward, two user equipment (UE)-based and UE-assisted C-V2X positioning architectures are proposed, and key technologies are also described. Lastly, testing and typical application cases are provided.