A two-step method of cyclolinopeptide (linusorb) preparation from flaxseed cake via dry-screening.

Linusorbs (LO), cyclolinopeptides, are a group of cyclic hydrophobic peptides and considered a valuable by-product of flaxseed oil due to numerous health benefits. Currently applied acetone or methanol extraction could contaminate the feedstocks for further food-grade application. Using flaxseed cake as feedstock, this study established a practical method for preparing LO from pressed cake. Firstly, LO composition of 15 flaxseed cultivars was analyzed. Next, cold-pressed cake was milled and screened mechanically. The kernel and hull fractions were separated based on the disparity of their mechanical strength. Monitored by hyperspectral fluorescence, the LO-enriched kernel fraction separated from cold-pressed flaxseed cake was further used as feedstock for LO production. After ethanol extraction, partition, and precipitation, LOs were extracted from cold-pressed flaxseed cake with a purity of 91.4%. The proposed method could serve as feasible flaxseed cake valorization strategy and enable the preparation of other polar compounds such as flax lignan and mucilage.

Stability of tryptophan-containing LOs in flaxseed oil and their response towards γ-tocopherol.

Linusorbs (LOs), significantly influence oil quality and sensory properties of flaxseed oil. Trp-containing LOs exhibit distinct oxidative behavior when γ-tocopherol (γ-T) is present. Polar fractions of crude flaxseed oil were stripped via silica absorption, and reintroduced (LO and γ-T) separately into the oil matrix to investigate their interaction during storage. Compared with crude oil, LOs account for 18.49% reduction of p-anisidine value, while LOs with γ-T contributed to most of the endogenous antioxidant effect in crude oil. γ-T was found to suppress oxidation of Trp-containing LO at early stage (Met form), while facilitate oxidation while at their mid-stage (MetO form, Methionine sulfoxide). In vitro oxidation shows that CLD more likely cleaved into peptide fragments, while few products retain intact ring structures. LC-MS/MS analysis and silicon simulation revealed proximity between MetO and Trp residues, facilitating inter- or intra-molecular reactions and ring structure rupture. Remarkably, the presence of γ-T facilitate these phenomena.

Temporal and Spatial Changes of Proarrhythmic Substrate in Premature Ventricular Contraction-Induced Cardiomyopathy.

BACKGROUND: The changes in proarrhythmic substrates and malignant ventricular arrhythmia mechanisms caused by premature ventricular contraction-induced cardiomyopathy (PVCCM) remain unclear. OBJECTIVES: The goal of this study was to establish the electrophysiological mechanism of how high-load PVC causes malignant arrhythmia. METHODS: Thirteen swine were exposed to 50% paced PVC from the right ventricular apex for 12 weeks (PVCCM, n = 6) and no pacing for 12 weeks (control, n = 7). Cardiac function was quantified biweekly with echocardiography. Computed tomography scans and electrophysiological examinations were performed monthly to dynamically evaluate the changes in the cardiac structure and the arrhythmogenic substrate. RESULTS: The decreases in the cardiac function and ventricular enlargement in the PVCCM group were significant after 12 weeks of PVC stimulation compared with the control group (P < 0.001). Electrophysiological examination found that the ventricular effective refractory period dispersion (0.071 ± 0.008), area of the low-voltage zone (9.41 ± 1.55 cm2), and malignant ventricular arrhythmia inducibility (33.3%) of the PVCCM group increased significantly at week 8 after pacing (P < 0.001 vs the control group); these changes slowed down after 8 weeks. Moreover, the distribution of the low-voltage zone presented obvious spatial heterogeneity, especially in the anterior wall of the right ventricle, accompanied by delayed activation in the sinus rhythm (67 ± 13 milliseconds). Consistently, the proportion of ventricular fibrosis- and expression-related proteins were significantly increased in the PVCCM group (P < 0.001), especially in the right ventricle. Moreover, proteomic analysis confirmed the spatial profile of these fibrotic changes in the PVCCM group. CONCLUSIONS: High-burden PVC can cause significant temporal and spatial heterogeneity changes in proarrhythmic substrates, which are potentially related to the upregulation of calcium signaling caused by asynchronous activation.

Absence of Rgs5 Influences the Spatial and Temporal Fluctuation of Cardiac Repolarization in Mice.

AIMS: This study investigated the contribution of the regulator of G-protein signaling 5 (Rgs5) knockout to the alteration of the action potential duration (APD) restitution and repolarizing dispersion in ventricle. METHODS AND RESULTS: The effects of Rgs5-/- were investigated by QT variance (QTv) and heart rate variability analysis of Rgs5-/- mice. Monophasic action potential analysis was investigated in isolated Rgs5-/- heart. Rgs5-/- did not promote ventricular remodeling. The 24-h QTv and QT variability index (QTVI) of the Rgs5-/- mice were higher than those of wild-type (WT) mice (P < 0.01). In WT mice, a positive correlation was found between QTv and the standard deviation of all NN intervals (r = 0.62; P < 0.01), but not in Rgs5-/- mice (R = 0.01; P > 0.05). The absence of Rgs5 resulted in a significant prolongation of effective refractory period and APD in isolated ventricle. In addition, compared with WT mice, the knockout of Rgs5 significantly deepened the slope of the APD recovery curve at all 10 sites of the heart (P < 0.01) and increased the spatial dispersions of Smax (COV-Smax) (WT: 0.28 ± 0.03, Rgs5-/-: 0.53 ± 0.08, P < 0.01). Compared with WT heart, Rgs5-/- increased the induced S1-S2 interval at all sites of heart and widened the window of vulnerability of ventricular tachyarrhythmia (P < 0.05). CONCLUSION: Our findings indicate that Rgs5-/- is an important regulator of ventricular tachyarrhythmia in mice by prolonging ventricular repolarization and increasing spatial dispersion in ventricle.

Clinical Safety and Efficacy of Ablation for Atrial Fibrillation Patients With a History of Stroke.

Objectives: To evaluate the clinical safety and efficacy of radiofrequency catheter ablation for atrial fibrillation patients with a history of stroke. Methods and Results: A total of 116 symptomatic, drug-refractory AF patients with a history of stroke, and 1:2 matched patients without a history of stroke were enrolled. Of these, 28 cases occurred stroke within 3 months (Group 1), 88 cases with stroke history longer than 3 months (Group 2), and 232 cases without stroke (Group 3). PVI was performed in all patients, extended to ablation of linear lesions ablation. The periprocedural stroke rates and other procedure-related in-hospital complications did not differ significantly among the three groups. The maintenance rate of SR after the procedure showed no significant difference (p = 0.333), 52.7, 66.4, and 70.7% in Group 1, 2, and 3, respectively. Furthermore, the comparison between a history of stroke and those without it were also shown no significant difference (p = 0.351). Conclusions: Radiofrequency ablation for AF patients occurred stroke, even within 3 months is safe and effective, without higher periprocedural complication rate and recurrence rate.

Overexpression of NDC80 is correlated with prognosis of pancreatic cancer and regulates cell proliferation.

AIMS: NDC80/Hec1, one of four proteins of the outer kinetochore NDC80 complex, is involved in the tumorigenesis of a variety of cancers. In this study, we focused on that NDC80 is overexpressed in human pancreatic cancer and investigates the role of NDC80-knockdown in pancreatic cancer cells proliferation. MATERIALS AND METHODS: We determined the expression levels of NDC80 on both mRNA and protein levels in fresh pancreatic cancer tissues and cells by quantitative real-time polymerase chain reaction and immunoblotting, respectively. Furthermore, protein level of NDC80 was identified using immunochemistry in paraffin-embedded tumor specimen, with correlation between NDC80 expression and various clinicopathological parameters evaluated. The role of NDC80 in pancreatic cancer cells (Panc-1) growth was investigated by lentivirus-mediated silencing of NDC80. The effect of NDC80 deletion on cell proliferation was analyzed by MTT assay and clone formation assay, while cell cycle distributions and apoptosis were analyzed by flow cytometry. RESULTS: The mRNA and protein of NDC80 were overexpressed in pancreatic cancer tissues and cells. The statistical analysis based on immunohistochemical evaluation suggested that NDC80 overexpression was signifi cantly associated with clinicopathological parameters including pathological T staging and N staging, which may be served as an predictor for poor outcomes. The silencing of NDC80 in Panc-1 cells could suppress cell proliferation and colony formation. Furthermore, the NDC80-siRNA infected Panc-1 cells lead to cell cycle arrest at G2/M phase and induction of apoptosis. CONCLUSION: These results demonstrated that NDC80 plays an essential role in the tumorigenesis of pancreatic cancer, and might serve as potential prognostic and therapeutic target for treatment of pancreatic cancer.