Numerical methods for hemolysis and thrombus evaluation in the percutaneous ventricular assist device.

BACKGROUND: A percutaneous ventricular assist device (pVAD) is an effective method to treat heart failure, but its complications, mainly hemolysis and thrombus formation, cannot be ignored. Accurate evaluation of hemolysis and thrombus formation in pVAD is essential to guide the development of pVAD and reduce the incidence of complications. METHODS: This study optimized the numerical model to predict hemolysis and thrombus formation in pVAD. The hemolysis model is based on the power law function, and the multi-component thrombus prediction model is improved by introducing the von Willebrand factor. RESULTS: The error between the numerical simulation and the hydraulic performance experiment is within 5%. The numerical results of hemolysis are in good agreement with those of in vitro experiments. Meanwhile, the thrombus location predicted by the numerical model is the same as that found in the in vivo experiment. CONCLUSION: The numerical model suggested in this study may therefore accurately assess the possible hemolytic and thrombotic dangers in pVAD, making it an effective tool to support the development of pVAD.

Liver extracellular volume fraction values obtained with magnetic resonance imaging can quantitatively stage liver fibrosis: a validation study in monkeys with nonalcoholic steatohepatitis.

OBJECTIVES: This study was to evaluate the diagnostic value of liver extracellular volume (LECV) for the staging of liver fibrosis in a cynomolgus monkey model of nonalcoholic steatohepatitis (NASH). METHODS: Forty-eight cynomolgus monkeys were enrolled in this prospective study. There are 17 healthy monkeys and 31 monkeys with NASH. Ten of these monkeys were used for repeatability assessment. The remaining 38 monkeys were used to compare LECV with other indicators including pathology fibrosis score, native T1, and serum chemical indexes by Spearman, Pearson correlation test, and ROC curves. The inter-reader variability was assessed by interclass correlation. The repeatability measurement of LECV was analyzed using Bland-Altman plots and the coefficient of variation. Partial correlation analysis was performed to assess the effects of fat content and inflammation scores on the correlation between LECV/T1 and liver fibrosis score. RESULTS: This study demonstrated a good intra-reader agreement (intraclass correlation = 0.79) of LECV in all monkeys and an excellent repeatability in 10 monkeys (coefficient of variation = 2.01%). The LECV has a strong correlation with the fibrosis score (r = 0.949; p < 0.0001), low-density lipoprotein (r = 0.72; p < 0.0001), and cholesterol (r = 0.70; p < 0.0001). LECV showed high diagnostic efficacy in the diagnosis of liver fibrosis (area under the curve of ROC, 0.945~1; p < 0.001). CONCLUSIONS: LECV may serve as a noninvasive valuable biomarker for the quantification and differentiating of the non-severe liver fibrosis (stage ≤ F3). However, circulating serum markers low-density lipoprotein and cholesterol (CHO) may not serve for this purpose. KEY POINTS: • This paper demonstrated the excellent repeatability (intraclass correlation coefficient = 0.79) of LECV in monkey animal model. • LECV-MRI has a strong correlation with histopathological fibrosis score stage (r = 0.949; p < 0.0001) and shows high diagnostic efficacy in the staging of non-severe liver fibrosis (the area under ROC curve ≥ 0.945). • The new fibrosis score maps appeared to provide a better imaging tool for the spatial assessment of liver fibrosis. It may eventually facilitate the diagnosis of liver fibrosis distribution.

microRNA-137 promotes endothelial progenitor cell proliferation and angiogenesis in cerebral ischemic stroke mice by targeting NR4A2 through the Notch pathway.

Cerebral ischemic stroke (CIS) is one of the common causes of death and disability worldwide. This study aims to investigate effect of miR-137 on endothelial progenitor cells and angiogenesis in CIS by targeting NR4A2 via the Notch pathway. Brain tissues were extracted from CIS and normal mice. Immunohistochemistry was used to determine positive rate of NR4A2 expression. Serum VEGF, Ang, HGF, and IκBα levels were determined by ELISA. RT-qPCR and Western blotting were used to determine expression of related factors. Endothelial progenitor cells in CIS mice were treated and grouped into blank, NC, miR-137 mimic, miR-137 inhibitor, siRNA-NR4A2, and miR-137 inhibitor + siRNA-NR4A2 groups, and cells in normal mice into normal group. Proliferation and apoptosis were determined by MTT and flow cytometry, respectively. NR4A2 protein expression was strongly positive in CIS mice, which showed higher serum levels of VEGF, Ang, and HGF but lower IκBα than normal mice. Compared with normal group, the rest groups (endothelial progenitor cells from CIS mice) showed decreased expressions of miR-137, Hes1, Hes5, and IκBα but elevated NR4A2, Notch, Jagged1, Hey-2, VEGF, Ang, and HGF, inhibited proliferation and enhanced apoptosis. Compared with blank and NC groups, the miR-137 mimic and siRNA-NR4A2 groups exhibited increased expression of miR-137, Hes1, Hes5, and IκBα, but decreased NR4A2, Notch, Jagged1, and Hey-2, with enhanced proliferation and attenuated apoptosis. The miR-137 inhibitor group reversed the conditions. miR-137 enhances the endothelial progenitor cell proliferation and angiogenesis in CIS mice by targeting NR4A2 through the Notch signaling pathway.

Central blockage of sympathetic nerves inhibits the abnormal vital signs and disturbance of the gut microbiota caused by continuous light exposure.

Background: Continuous light exposure increases sympathetic excitation in rats, leading to hypertension, left ventricular hypertrophy, and fibrosis. This study was aimed to investigate whether continuous light exposure causes destabilization of vital signs and gut microbiota (GM) in Sprague Dawley (SD) rats and whether clonidine hydrochloride (CH), a central sympathetic depressant drug, could prevent these changes. Methods: Eight-week-old male SD rats were divided into three groups with different interventions for 14 weeks: control group (CG), 2-mL pure water gavaged daily while on a normal 12-h light/dark cycle; continuous illumination group (CI), 2-mL pure water gavaged daily while receiving continuous exposure to light (300 lx); and drug administration group (DA), CH (10 µg/kg) gavaged daily while receiving continuous exposure to light (300 lx). Results: The results showed that blood pressure, heart rate, and body weight were significantly higher in the CI group than in the CG and DA groups (P < 0.05). Moreover, the Shannon index was higher in the DA group than in the CI group (P = 0.012). The beta diversity index in the CG group was significantly higher in the CI group (P = 0.039). The pairwise comparison results of the linear discriminant analysis effect size showed that Oscillospirales were enriched in the DA group, whereas the Prevotellaceae lineage (family level) > Prevotella (genus level) > Prevotellaceae_bacterium (species level) were enriched in the CI group. The Muribaculaceae family was more abundant in the CG group than in the CI group. Conclusion: Sympathetic nerve inhibition restored the abnormal vital signs and GM changes under continuous light exposure.

Imaging characterization of myocardial function, fibrosis, and perfusion in a nonhuman primate model with heart failure-like features.

Introduction: The availability of a human-like chronic heart failure (HF) animal model was critical for affiliating development of novel therapeutic drug treatments. With the close physiology relatedness to humans, the non-human primate (NHP) HF model would be valuable to better understand the pathophysiology and pharmacology of HF. The purpose of this work was to present preliminary cardiac image findings using echocardiography and cardiovascular magnetic resonance (CMR) in a HF-like cynomolgus macaque model. Methods: The NHP diet-induced model developed cardiac phenotypes that exhibited diastolic dysfunction with reduced left ventricular ejection fraction (LVEF) or preserved LVEF. Twenty cynomolgus monkeys with cardiac dysfunction were selected by echocardiography and subsequently separated into two groups, LVEF < 65% (termed as HFrEF, n = 10) and LVEF ≥ 65% with diastolic dysfunction (termed as HFpEF, n = 10). Another group of ten healthy monkeys was used as the healthy control. All monkeys underwent a CMR study to measure global longitudinal strain (GLS), myocardial extracellular volume (ECV), and late gadolinium enhancement (LGE). In healthy controls and HFpEF group, quantitative perfusion imaging scans at rest and under dobutamine stress were performed and myocardial perfusion reserve (MPR) was subsequently obtained. Results: No LGE was observed in any monkey. Monkeys with HF-like features were significantly older, compared to the healthy control group. There were significant differences among the three groups in ECV (20.79 ± 3.65% in healthy controls; 27.06 ± 3.37% in HFpEF group, and 31.11 ± 4.50% in HFrEFgroup, p < 0.001), as well as for stress perfusion (2.40 ± 0.34 ml/min/g in healthy controls vs. 1.28 ± 0.24 ml/min/g in HFpEF group, p < 0.01) and corresponding MPR (1.83 ± 0.3 vs. 1.35 ± 0.29, p < 0.01). After adjusting for age, ECV (p = 0.01) and MPR (p = 0.048) still showed significant differences among the three groups. Conclusion: Our preliminary imaging findings demonstrated cardiac dysfunction, elevated ECV, and/or reduced MPR in this HF-like NHP model. This pilot study laid the foundation for further mechanistic research and the development of a drug testing platform for distinct HF pathophysiology.

Computed tomography-guided biopsy of small lung nodules: diagnostic accuracy and analysis for true negatives.

OBJECTIVE: We evaluated the diagnostic accuracy of computed tomography (CT)-guided transthoracic core needle biopsy (TCNB) for small (≤20-mm) lung nodules and identified predictive factors for true negatives among benign biopsy results. METHODS: From March 2010 to June 2015, 222 patients with small lung nodules underwent CT-guided TCNB. We retrospectively analysed data regarding technical success, diagnostic accuracy, and predictors of true negatives. RESULTS: The technical success rate was 100%. The TCNB results of the 222 lung nodules included malignancy (n = 136), suspected malignancy (n = 8), specific benign lesion (n = 17), and nonspecific benign lesion (n = 61). The final diagnosis of 222 lung nodules included malignant (n = 160), benign (n = 60), and nondiagnostic lesions (n = 2). The sensitivity, specificity, and overall diagnostic accuracy of CT-guided TCNB for small lung nodules were 90.0%, 100%, and 92.7%, respectively. Pneumothorax and haemoptysis occurred in 23 and 41 patients, respectively. Based on the Cox regression analysis, the significant independent predictive factor for true negatives was a biopsy result of chronic inflammation with fibroplasia. CONCLUSIONS: CT-guided TCNB offers high diagnostic accuracy for small lung nodules, and a biopsy result of chronic inflammation with fibroplasia can predict a true-negative result.

[Determining the relationship between coronary artery and coronary sinus and its tributaries using multislice computed tomography].

OBJECTIVE: To obtain the coronary artery and coronary sinus (CS) and its tributaries imaging with multislice computed tomography (MSCT), measure the distance between coronary artery and CS and its tributaries and analyze their spatial relationships. METHODS: The MSCT scans of 117 patients (67 men, 50 women, age 56 +/- 10 years) were obtained, 3D image reconstructed and the vessels courses evaluated. The concomitant distances and spatial relationships of the vessels were determined. RESULTS: Right coronary artery domination was found in 107 cases (91.4%), left coronary artery domination in 7 cases (6.0%), and co-domination in 3 cases (2.6%). Left circumflex artery (LCX) was concomitant with CS or the great cardiac vein (GCV) in 81 cases (69.2%), intersected with left posterior vein in 62 cases (53.0%) and with middle cardiac vein (MCV) in 5 cases (4.3%), respectively. The dominant coronary artery branched out into the posterior descending artery (PDA) and the left posterior artery (LPA) in 112 cases (95.7%). PDA was concomitant with MCV in 93 cases (79.5%) and intersected with MCV in 44 cases (37.6%). LPA was intersected with MCV in 106 cases (90.6%), and concomitant with CS in 50 cases (42.7%). CONCLUSIONS: MSCT is a reliable tool to visualize the relationship between coronary artery and CS and its tributaries. Owing to the multiple possibilities inherent to this technique, MSCT has broad potential for more clinical use.

Complete genome sequence analysis of a predominant infectious bronchitis virus (IBV) strain in China.

Infectious bronchitis (IB) is one of the major diseases in poultry flocks all over the world caused by infectious bronchitis virus (IBV). In the study, the complete genome sequence of strain A2 was sequenced and analyzed, which was a predominant IBV strain in China. The results indicated that there were mutations, insertions, and deletions distributed in the whole genome. The A2 virus had the highest identity to S14 and BJ in terms of full genome, whereas had a further distance to Massachusetts strains. Phylogenetic analysis showed that A2 isolate clustered together with most Chinese strains. The results of this study suggest that strain A2 may play an important role in IBV's evolution and A2-like IBVs are predominant strains in China.