Feasibility and reproducibility of semi-automated longitudinal strain analysis: a comparative study with conventional manual strain analysis.

BACKGROUND: Conventional approach to myocardial strain analysis relies on a software designed for the left ventricle (LV) which is complex and time-consuming and is not specific for right ventricular (RV) and left atrial (LA) assessment. This study compared this conventional manual approach to strain evaluation with a novel semi-automatic analysis of myocardial strain, which is also chamber-specific. METHODS: Two experienced observers used the AutoStrain software and manual QLab analysis to measure the LV, RV and LA strains in 152 healthy volunteers. Fifty cases were randomly selected for timing evaluation. RESULTS: No significant differences in LV global longitudinal strain (LVGLS) were observed between the two methods (-21.0% ± 2.5% vs. -20.8% ± 2.4%, p = 0.230). Conversely, RV longitudinal free wall strain (RVFWS) and LA longitudinal strain during the reservoir phase (LASr) measured by the semi-automatic software differed from the manual analysis (RVFWS: -26.4% ± 4.8% vs. -31.3% ± 5.8%, p < 0.001; LAS: 48.0% ± 10.0% vs. 37.6% ± 9.9%, p < 0.001). Bland-Altman analysis showed a mean error of 0.1%, 4.9%, and 10.5% for LVGLS, RVFWS, and LASr, respectively, with limits of agreement of -2.9,2.6%, -8.1,17.9%, and -12.3,33.3%, respectively. The semi-automatic method had a significantly shorter strain analysis time compared with the manual method. CONCLUSIONS: The novel semi-automatic strain analysis has the potential to improve efficiency in measurement of longitudinal myocardial strain. It shows good agreement with manual analysis for LV strain measurement.

Early detect left ventricular subclinical myocardial dysfunction in patients with systemic lupus erythematosus by a left ventricular pressure-strain loop.

OBJECTIVE: Noninvasive myocardial work (MW) is a new technology which is based on strain after considering the load influence on myocardial deformation. We aimed to investigate the feasibility of quantitatively assessing left ventricular myocardial work (LVMW) in patients with systemic lupus erythematosus (SLE) using a left ventricular pressure-strain loop (LVPSL). METHODS: 76 patients with SLE were included in the study (A), further divided into two subgroups according to the presence of lupus nephritis (LN). Global longitudinal strain (GLS), peak strain dispersion (PSD), global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were obtained. RESULTS: 1: Patients with SLE demonstrated a significantly reduced GWE and GLS compared with control group, GWW and PSD were increased, above changes were more pronounced in patients with LN. There was no significant difference in GWI and GCW. 2: Receiver operating characteristic (ROC) analysis demonstrated that GWE was the most powerful tool for detecting myocardial insufficiency early in SLE patients, and the area under the curve (AUC) was 0.804, and was superior to GLS (AUC = 0.707). GWE remains the best indicator of subclinical myocardial injury in patients with LN. The AUC was 0.910, and the best cutoff point was 96.5% (sensitivity 83.3%, specificity 73.3%). CONCLUSIONS: LVPSL can be used to noninvasively assess changes in MW in patients with SLE. Noninvasive GWE is a more sensitive index than GLS to detect subclinical myocardial injury early in SLE patients. This is a potential valuable clinical tool to assist in the early-find myocardial damage.

Nanomedicines based on nanoscale metal-organic frameworks for cancer immunotherapy.

Cancer immunotherapy, with an aim to enhance host immune responses, has been recognized as a promising therapeutic treatment for cancer. A diversity of immunomodulatory agents, including tumor-associated antigens, adjuvants, cytokines and immunomodulators, has been explored for their ability to induce a cascading adaptive immune response. Nanoscale metal-organic frameworks (nMOFs), a class of crystalline-shaped nanomaterials formed by the self-assembly of organic ligands and metal nodes, are attractive for cancer immunotherapy because they feature tunable pore size, high surface area and loading capacity, and intrinsic biodegradability. In this review we summarize recent progress in the development of nMOFs for cancer immunotherapy, including cancer vaccine delivery and combination of in situ vaccination with immunomodulators to reverse immune suppression. Current challenges and future perspectives for rational design of nMOF-based cancer immunotherapy are also discussed.

Production of Bioactive Recombinant Bovine Chymosin in Tobacco Plants.

Chymosin (also known as rennin) plays an essential role in the coagulation of milk in the cheese industry. Chymosin is traditionally extracted from the rumen of calves and is of high cost. Here, we present an alternative method to producing bovine chymosin from transgenic tobacco plants. The CYM gene, which encodes a preprochymosin from bovine, was introduced into the tobacco nuclear genome under control of the viral 35S cauliflower mosaic promoter. The integration and transcription of the foreign gene were confirmed with Southern blotting and reverse transcription PCR (RT-PCR) analyses, respectively. Immunoblotting analyses were performed to demonstrate expression of chymosin, and the expression level was quantified by enzyme-linked immunosorbent assay (ELISA). The results indicated recombinant bovine chymosin was successfully expressed at an average level of 83.5 ng/g fresh weight, which is 0.52% of the total soluble protein. The tobacco-derived chymosin exhibited similar native milk coagulation bioactivity as the commercial product extracted from bovine rumen.

Chloroplast-expressed MSI-99 in tobacco improves disease resistance and displays inhibitory effect against rice blast fungus.

Rice blast is a major destructive fungal disease that poses a serious threat to rice production and the improvement of blast resistance is critical to rice breeding. The antimicrobial peptide MSI-99 has been suggested as an antimicrobial peptide conferring resistance to bacterial and fungal diseases. Here, a vector harboring the MSI-99 gene was constructed and introduced into the tobacco chloroplast genome via particle bombardment. Transformed plants were obtained and verified to be homoplastomic by PCR and Southern hybridization. In planta assays demonstrated that the transgenic tobacco plants displayed an enhanced resistance to the fungal disease. The evaluation of the antimicrobial activity revealed that the crude protein extracts from the transgenic plants manifested an antimicrobial activity against E. coli, even after incubation at 120 °C for 20 min, indicating significant heat stability of MSI-99. More importantly, the MSI-99-containing protein extracts were firstly proved in vitro and in vivo to display significant suppressive effects on two rice blast isolates. These findings provide a strong basis for the development of new biopesticides to combat rice blast.

Stable Expression of Basic Fibroblast Growth Factor in Chloroplasts of Tobacco.

Basic fibroblast growth factor (bFGF) is a multifunctional factor in acceleration of cell proliferation, differentiation and transference, and therefore widely used in clinical applications. In this study, expression vector pWX-Nt03 harboring a codon-optimized bFGF gene was constructed and introduced into the tobacco chloroplasts by particle bombardment. After four rounds of selection, bFGF was proved to integrate into the chloroplast genome of regenerated plants and two of four transgenic plants were confirmed to be homoplastomic by PCR and Southern hybridization. ELISA assay indicated that bFGF represented approximately 0.1% of total soluble protein in the leaves of transplastomic tobacco plants. This is the first report of bFGF expression via chloroplast transformation in model plant, providing an additional option for the production of chloroplast-produced therapeutic proteins.

Functional Connectivity Alterations and Molecular Characterization of the Anterior Cingulate Cortex in Tinnitus Pathology without Hearing Loss.

Compared with individuals with hearing loss, tinnitus patients without hearing loss have more psychological or emotional problems. Tinnitus is closely associated to abnormal metabolism and function of the limbic system, a key brain region for emotion experience, but the underlying molecular mechanism remains unknown. Using whole-brain microvasculature dynamics imaging, the anterior cingulate cortex (ACC) is identified as a key brain region of limbic system involve in the onset of salicylate-induced tinnitus in mice. In the tinnitus group, there is enhanced purine metabolism, oxidative phosphorylation, and a distinct pattern of phosphorylation in glutamatergic synaptic pathway according to the metabolome profiles, quantitative proteomic, and phosphoproteomic data of mice ACC tissue. Electroencephalogram in tinnitus patients with normal hearing thresholds show that the functional connectivity between pregenual anterior cingulate cortex and the primary auditory cortex is significantly increased for high-gamma frequency band, which is positively correlated with the serum glutamate level. These findings indicate that ACC plays an important role in the pathophysiology of tinnitus by interacting with the primary auditory cortex and provide potential molecular targets in the ACC for tinnitus treatment.

Left atrial reservoir and pump function after catheter ablation with persistent atrial fibrillation: a two-dimensional speckle tracking imaging study.

OBJECTIVE: By using ultrasound strain rate (SR) imaging to evaluate the left atrial (LA) reservoir and pump function after catheter ablation (CA) with persistent atrial fibrillation (PAF). METHODS: A total of 45 patients with PAF underwent echocardiography examination before and after ablation as well as during 6 months of follow-up. Peak SR was measured at each LA segment (septal, lateral, anterior, inferior and posterior) during systole (LAs) and late diastole (LAa). RESULTS: During 6 months after CA, 30 patients were free of atrial fibrillation recurrence (AFR). left atrial area index (LAAI), left atrial maximum volume index (LAVImax), and E/Ea were obviously higher in patients with before CA, left atrial ejection fraction (LAEF), SR-LAs were lower than in normal cases, the SR-LAa was disappeared. Shortly after ablation, SR-LAa was recovered, and SR-LAs was reduced compared to those at baseline. At midterm follow-up, LAEF and SR-LAs were still lower than the control group, and LAAI and LAVImax were higher. SR-LAa was recovered slowly over time, but still lower. CONCLUSION: LA reservoir function was seriously damaged and LA pump function disappeared in patients with PAF. LA reservoir function impairment appeared shortly after ablation, it showed improvement at midterm follow-up, but some degree of damage to the LA reservoir and pump function was still present. Speckle tracking imaging is a feasible technique for the assessment of LA function in patients with PAF, which is a potentially valuable clinical tool to assist in the early detection of atrial remodelling and reverse remodelling.