Inter‐ and intramuscular differences in training‐induced hypertrophy of the quadriceps femoris: association with muscle activation during the first training session

The purpose of this study was to examine whether inter‐ and intramuscular differences in hypertrophy induced by resistance training correspond to differences in muscle activation during the first training session. Eleven young men completed 12 weeks of training intervention for knee extension. Before and after the intervention, T1‐weighted magnetic resonance (MR) images were recorded to determine the volume and anatomical cross‐sectional area (CSA) along the length of the individual muscles of the quadriceps femoris. The T2‐weighted MR images were also acquired before and immediately after the first training session. The T2 was calculated for each pixel within the quadriceps femoris, from which the muscle activation was evaluated as %activated volume and area. The results showed that the %activated volume after the first training session was significantly higher in the vastus intermedius than the vastus medialis. However, the relative change in muscle volume after the training intervention was significantly greater in the rectus femoris than the vasti muscles (vastus lateralis, intermedius and medialis). Within the rectus femoris, both the %activated area and relative increase in CSA were significantly greater in the distal region than the proximal region. In contrast, the %activated area and relative increase in CSA of the vasti were nearly uniform along each muscle. These results suggest that the muscle activation during the first training session is associated with the intramuscular difference in hypertrophy induced by training intervention, but not with the intermuscular difference.     

A novel cell line generated using the CRISPR/Cas9 technology as universal quality control material for KRAS G12V mutation testing

Background

KRAS mutations are the key indicator for EGFR monoclonal antibody‐targeted therapy and acquired drug resistance, and their accurate detection is critical to the clinical decision‐making of colorectal cancer. However, no proper quality control material is available for the current detection methods, particularly next‐generation sequencing (NGS). The ideal quality control material for NGS needs to provide both the tumor mutation gene and the matched background genomic DNA, which is uncataloged in public databases, to accurately distinguish germline polymorphisms and somatic mutations.

Methods

We developed a novel KRAS G12V mutant cell line using the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR‐associated protein 9 (Cas9) technique to make up for the deficiencies in existing quality control material and further validated the feasibility of the cell line as quality control material by amplification refractory mutation system (ARMS), Sanger sequencing, digital PCR (dPCR), and NGS.

Results

We verified that the edited cell line specifically had the G12V mutation, and the validation results presented a high consistency among the four methods of detection. The three cell lines screened contained the G12V mutation and the mutation allele fractions of G12V‐1, G12V‐2, and G12V‐3 were 52.01%, 82.06%, and 17.29%, respectively.

Conclusion

The novel KRAS G12V cell line generated using the CRISPR/Cas9 gene editing system is suitable as a quality control material for all current detection methods and provides a new direction in the development of quality control material.

     

Contrast‐enhanced ultrasound using bolus injections of contrast agent for assessment of postprandial microvascular blood volume in human skeletal muscle

Methods capable of measuring blood flow in a tissue‐specific manner are needed. The purpose of this study was to investigate whether contrast‐enhanced ultrasound (CEUS) using bolus injections of SonoVue^® is an useful method for assessing postprandial changes in microvascular perfusion in the vastus lateralis muscle. Ten healthy, young subjects were recruited for this study. Six subjects participated in washout and reproducibility protocols to assess washout time of SonoVue^® and the reproducibility of the method when measuring microvascular blood volume (MBV). Six subjects (two of which also participated in the washout and reproducibility protocols) participated in exercise and nutrition protocols, to assess the ability of the method to detect changes in MBV in response to these interventions. Intraday variation (coefficients of variation) for MBV indices, as assessed by peak signal intensity (PI) or mean plateau signal intensity (mPI), was high (PI: 19 ± 4·2%; mPI: 23 ± 3·3%). The exercise protocol induced significant increases in MBV indices (PI:+113%, P?0·0001; mPI:+218%, P?0·0001) acutely after exercise cessation. There were no changes in MBV indices in response to feeding during the nutrition protocol (PI: P = 0·51; mPI: P = 0·51). We conclude that CEUS using bolus injections of SonoVue^® is not capable of detecting changes in MBV of vastus lateralis in response to feeding. This is probably due to the low reproducibility of the method. However, the method is capable of measuring changes in MBV in response to exercise. This method could therefore be used when investigating exercise‐induced changes in microvascular perfusion.     

爱通立溶栓治疗脑梗死患者的人性化护理

目的:探讨爱通立溶栓治疗脑梗死患者的人性化护理体会.方法:选择53例脑梗死患者作为研究对象,给予爱通立溶栓治疗,并配合密切的人性化护理.结果:51例患者病情得到缓解(96.2%),2例死亡(3.8%),患者对护理服务均表示满意.结论:人性化护理对促进患者保持良好的身心状态和顺利康复具有重要意义.