Objective To explore the clinical value of shear wave elastography in the evaluation of quadriceps femoris lesions in patients with chronic obstructive pulmonary disease (COPD). Methods Fifty-eight COPD patients who were admitted to Chengdu First People’s Hospital and 55 healthy controls were included in the study between August 2021 and February 2022. The thickness, circumference, cross-sectional area and Young's modulus of quadriceps femoris in all subjects were measured using shear wave elastography combined with conventional two-dimensional ultrasound. The differences in ultrasound parameters between the two groups were compared, and the correlation between each ultrasound parameter and clinical evaluation indicators (modified British Medical Research Council Scale, COPD Assessment Test, six-minute walk test, and five-time sit-to-stand test) was analyzed. Results Young’s modulus values of the quadriceps femoris muscle were smaller in the COPD group than those in the healthy control group [COPD Group: rectus femoris 6.72 (6.22, 7.36) kPa, vastus medialis 6.25 (5.82, 6.79) kPa, vastus lateralis 6.94 (6.17, 7.48) kPa; healthy control group: rectus femoris 11.40 (10.23, 12.11) kPa, vastus medialis 10.77 (9.62, 11.42) kPa, vastus lateralis 11.14 (10.42, 12.52) kPa]. The differences were statistically significant (all P<0.05). The Young's modulus value of the rectus femoris muscle correlates with the aforementioned clinical evaluation indicators, with positive correlation with six-minute walk distance and negative correlation with COPD Assessment Test, modified British Medical Research Council Scale, five-time sit-to-stand time (P<0.05). Quadriceps thickness, circumference, and cross-sectional area measured by conventional two-dimensional ultrasound were not significantly different between the two groups, nor were there significant correlations between each parameter and clinical parameters (P>0.05). In addition, shear wave elastography has good reproducibility in the measurement of Young's modulus in quadriceps. Conclusions Shear wave elastography can identify quadriceps lesions earlier than conventional two-dimensional ultrasound in COPD patients, and there is a significant correlation between its measurements and the clinical condition of COPD patients. Shear wave elastography may provide a simple and noninvasive method for clinical evaluation of quadriceps femoris lesions in COPD patients.
The purpose of this study is to investigate the effects of self-assembling peptide GFS-4 on three-dimen-sional myocardial cell culture and tissue repair of myocardial infarction. The circular dichroism (CD) spectrum was used to detect secondary structure of GFS-4, and atomic force microscope (AFM) was used to analyze the microstructure of self-assembly. The nanofiber scaffolds self-assembled by GFS-4 were used as the three-dimensional culture material to observe the growth effect of cardiomyocytes. The model of myocardial infarction was established and the effect of GFS-4 on myocardial infarction was studied. The results indicated that self-assembling peptide GFS-4 could form mainly β-sheet structure that can form dense nanofiber scaffolds after 24 hours’ self-assembling. The myocardial cells had a favorable growth status in GFS-4 nanofiber scaffold hydrogel when cells treated in three-dimen-sional cell culture. The experiment of repairing myocardial infarction in vitro proved that peptide GFS-4 hydrogel scaffold could alleviate tissue necrosis in a myocardial infarction area. As a new nanofiber scaffold material, self-assembling peptide GFS-4 can be used for three-dimensional cell culture and tissue repairing in myocardial infarction area.