Evaluation of Myocardial Microcirculation in Rats under a High-Altitude Hypoxic Environment by Computed Tomography Myocardial Perfusion Imaging.

This study aims to examine the changes in myocardial microcirculation in rats in a high-altitude hypoxic environment via computed tomography (CT) myocardial perfusion imaging technology. Rats in two groups were raised in different environments from 4 weeks of age for a period of 24 weeks. At 28 weeks of age, both groups underwent CT myocardial perfusion scanning, and the following myocardial perfusion parameters were measured: time to peak (TTP), mean transit time (MTT), blood flow (BF), and blood volume (BV). Following the scan, the rats were sacrificed, the cardiac index and right ventricular hypertrophy index were obtained, and hematoxylin-eosin (HE) staining was utilized to observe the pathological changes in the myocardium. In the group of rats that are subject to a high-altitude hypoxic environment for 24 weeks (the high-altitude group), the TTP and MTT values were increased (P < 0.05), the BF and BV values were lower (P < 0.05), the right heart mass was higher (P < 0.05) than that in the low-altitude group. As shown by the pathological results of HE staining, the gap between cardiomyocytes in the high-altitude group was widened, the arrangement of cardiomyocytes was irregular, and the cells were filled with a few fat vacuoles. The myocardial microcirculation is altered in a high-altitude hypoxic environment. In particular, the myocardium is in a state of inadequate perfusion, the BF in the myocardium slows down, and the right heart displays compensatory hypertrophy.

Biomimetic soft micro-swimmers: from actuation mechanisms to applications.

Underwater robot designs inspired by the behavior and morphological characteristics of aquatic animals can provide reinforced mobility and energy efficiency. In the past two decades, the emerging materials science and integrated circuit technology have been combined and applied to various types of bionic soft underwater miniaturized robots by researchers around the world. Further, the potential applications of biomimetic soft micro-swimmers in the biological and medical fields have been explored. Here, this paper reviews the development of biomimetic soft tiny swimmers, which are designed based on a variety of intelligent materials and control strategies. This review focuses on the various actuation mechanisms of soft tiny swimmers reported in the past two decades and classifies these robots into four categories: fish-like, snake-like, jellyfish-like and microbial-inspired ones. Besides, this review considers the practical challenges faced by actuation mechanisms of each type of robot, and summarizes and prospects how these challenges affect the potential applications of robots in real environments.

Evaluation of cardiac index and right ventricular hypertrophy index in rats under a chronic hypoxic environment at high altitude.

High-altitude areas are characterized by low pressure and hypoxia, which have a significant impact on various body systems. This study aimed to investigate the alterations in cardiac index and right ventricular hypertrophy index(RVHI) in rats at different altitudes.Twenty-one male Sprague-Dawley (SD) rats aged 4 weeks were randomly divided into three groups based on altitude. The rats were raised for 28 weeks and then transferred to Qinghai University Plateau Medicine Laboratory. Body weight was measured, heart organs were isolated and weighed, and cardiac index and right ventricular hypertrophy index were determined. Statistical analysis was performed on the data from the three groups. Compared with the plain group, the body weight of the middle-altitude group was significantly decreased (P < 0.05), and cardiac index, RVHI-1, RVHI-2 increased significantly ((P < 0.05). The body weight, whole heart mass, right ventricular mass were significantly decreased in high-altitude group (P < 0.05), RVHI-1 and RVHI-2 were significantly increased (P < 0.05). Compared with the middle-altitude group, the body weight, whole heart mass and right ventricular mass of the high-altitude group were significantly decreased (P < 0.05), and RVHI-1 and RVHI-2 were significantly increased (P < 0.05). Increasing altitude led to a decrease in body weight, whole heart mass, and right ventricular mass in rats, indicating structural changes in the right heart. Additionally, the proportion of right heart to body weight and whole heart increased with altitude.

Correlation of the Gut Microbiota and Antitumor Immune Responses Induced by a Human Papillomavirus Therapeutic Vaccine.

Human papillomavirus (HPV) is the most common sexually transmitted pathogen worldwide and the major risk factor for cervical cancer. According to our previous study, antitumor immune responses induced by a therapeutic vaccine based on HPV E7 peptide are highly variable among individuals. Many studies have demonstrated that the discrepancy in the gut microbiota is an important factor in the development and regulation of the immune system. Therefore, we performed a systematic comparative analysis of gut microbiota in two groups of mice with significant differences in antitumor effects induced by the vaccine, as well as the correlation between immune cells and gut microbiota. We divided the mice into group A, in which the tumor continued growing, and group B, in which the tumor volume was significantly reduced. In group B mice, the vaccination induced a stronger antitumor activity with significantly enhanced IFN-γ-producing CD4+ and CD8+ T lymphocytes, as well as decreased immunosuppressive cells. A detailed gut microbiota analysis revealed a positive Spearman correlation between the percentage of CD8+ T cells and the relative abundance of Corynebacteriales, Parabacteroides, and Bacteroides_sp. Furthermore, the percentage of CD4+ and CD8+ T cells negatively correlated with the abundance of Proteobacteria and Bilophila. By contrast, the abundance of Proteobacteria, Desulfovibrio, and Bilophila positively correlated with the percentage of myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), and type 2-polarized tumor-associated macrophages (M2-TAMs). Overall, the composition of gut microbiota is related to vaccine-induced antitumor effects, and there is a correlation between some gut bacteria and vaccine-induced immune responses.

Development and validation of a deep learning model for survival prognosis of transcatheter arterial chemoembolization in patients with intermediate-stage hepatocellular carcinoma.

PURPOSE: We aimed to develop a deep learning-based approach to evaluate both time-to-progression (TTP) and overall survival (OS) prognosis of transcatheter arterial chemoembolization (TACE) in treatment-naïve patients with intermediate-stage hepatocellular carcinoma (HCC) and compare the approach's performance with those of radiomics and clinical models. METHODS: EfficientNetV2 was used to build a prognosis model for treatment-naïve patients with HCC. Data of 414 intermediate-stage HCC patients from one participant center were collected to construct the training and validation datasets (70%:30%) for TTP prognosis, while data of 129 intermediate-stage HCC patients from another participant center were collected as the test dataset for both TTP and OS prognosis. Three radiomics and three clinical models were then constructed for comparison. RESULTS: Patients with EfficientNetV2-based model score ≤ 0.5 had better TTP than those with higher scores (hazard ratio [HR]: 0.32, 95%CI: 0.22-0.46, P < 0.0001; HR: 0.28, 95%CI: 0.20-0.41, P < 0.0001; and HR: 0.55, 95%CI: 0.36-0.88, P = 0.005 in the training, validation, and test datasets, respectively). Patients with model score ≤ 0.5 had better OS (38.8 months vs 20.9 months, HR: 0.58, 95%CI: 0.37-0.90, P = 0.008). Compared with the radiomics (intra-tumoral and peri-tumoral) and three clinical models, the EfficientNetV2-based model showed better survival prognosis for TACE (P < 0.05) in the test dataset. CONCLUSIONS: The EfficientNetV2-based model enables assessment of both TTP and OS prognosis of TACE in treatment-naïve, intermediate-stage HCC. Patients with lower scores will benefit from TACE. The model can potentially be used by clinicians to improve decision making regarding TACE treatment choices.

Visible Light-Driven Jellyfish-like Miniature Swimming Soft Robot.

Soft actuators that exhibit large deformation and can move at a fast speed in response to external stimuli have been in high demand for biomimetic applications. In this paper, we propose a convenient approach to fabricate a reversible and thermal-responsive composite hydrogel. Under the irradiation of visible light, the striped hydrogel can bend at a speed of up to 65.72°/s with carbon nanotubes loaded at a concentration of 3 mg/mL. A jellyfish-like miniature soft robot is made using this hydrogel. When driven by visible light, the robot can move at a maximum speed of 3.37 mm/s. Besides swimming, other motion modes, including walking and jumping, are also achieved by the robot. In addition, the robot can perform directional transportation of tiny objects. As a new actuation approach for the research of jellyfish-like miniature soft robots, this work is of great significance to the development of flexible bionic robots. Moreover, this work also offers some important insights into the research of biomimetic robots driven by visible light.