BackgroundStudies on the relationship between osteoporosis and intervertebral disc degeneration (IVDD) are inconsistent. Therefore, we assessed whether IVDD is affected by vertebral osteoporosis in ovariectomized mice and investigated the underlying pathogenesis of IVDD related to osteoporosis.MethodsThirty healthy female C57BL/6 J mice aged 8 weeks were randomly divided into two groups: a control group (sham operation, n = 15) and an ovariectomy group (OVX; bilateral ovariectomy, n = 15). At 12 weeks after surgery, the bone quantity and microstructure in the lumbar vertebra and endplate as well as the volume of the L4/5 disc space were evaluated by microcomputed tomography (micro-CT). The occurrence and characteristic alterations of IVDD were identified via histopathological staining. The osteoclasts were detected using tartrate-resistant acid phosphatase (TRAP) staining. Type II collagen (Col II), osterix (OSX), osteopontin (OPN), and vascular endothelial growth factor (VEGF) expression in the intervertebral disc were detected by immunohistochemical analysis.ResultsOVX significantly increased the body weight and decreased the uterus weight. Micro-CT analysis showed that osteoporosis of the vertebra and osteochondral remodeling of the endplate were accompanied by an increase in the endplate porosity and a decrease in the disc volume in the OVX group. Likewise, histological evaluation revealed that IVDD occurred at 12 weeks after ovariectomy, with features of endochondral ossification of the endplate, loose and broken annulus fibrosus, and degeneration of nucleus pulposus. TRAP staining showed that numerous active osteoclasts appeared in the subchondral bone and cartilaginous endplate of OVX mice, whereas osteoclasts were rarely detected in control mice. Immunohistochemical analysis demonstrated that the expression of osterix was significantly increased, notably in the endplate of OVX mice. In addition, Col II was decreased in the ossification endplate and the degenerative annulus fibrosus, where OPN and VEGF expressions were elevated in OVX mice.ConclusionsOVX induced vertebral osteoporosis and osteochondral remodeling of the cartilaginous endplate contributing to the angiogenesis and an increase in porosity of the bone-cartilage surface, and also affected the matrix metabolism which consequently had detrimental effects on the intervertebral disc. Our study suggests that preserving the structural integrity and the function of the adjacent structures, including the vertebrae and endplates, may protect the disc against degeneration.Electronic supplementary materialThe online version of this article (10.1186/s13075-018-1701-1) contains supplementary material, which is available to authorized users.

With the popularity of social networking sites, enterprises start to establish their own brand communities to manage and maintain customer relationships. Consumer stickiness is regarded as one of the critical determinants for the success of a brand community. Enhancing consumers' stickiness to online communities can lead to repurchase behavior and positive word-of-mouth and thereby increase sales volume and customer recruitment. This study endeavors to explore the antecedents of consumers' stickiness to a SNS-based online brand community from the aspects of enterprises and consumers. Data were collected through online questionnaires conducted on Do-Survey website with a hyperlink posted on the PTT, the largest BBS website of Taiwan. After excluding non-usable data, the final sample size was 516. The results indicated that information quality, perceived value, and community identification have positive effects on consumers' stickiness to online brand communities. Moreover, stickiness to online brand communities has positive impacts on customer loyalty.

The electrocardiogram (ECG) is one of the physiological signals applied in medical clinics to determine the health status. The physiological complexity of the cardiac system is related to age, disease, etc. For the investigation of the effects of age and cardiovascular disease on the cardiac system, we then construct multivariate recurrence networks with multiple scale factors from multivariate time series. We propose a new concept of cross-clustering coefficient entropy to construct a weighted network, and calculate the average weighted path length and the graph energy of the weighted network to quantitatively probe the topological properties. The obtained results suggest that these two network measures show distinct changes between different subjects. This is because, with aging or cardiovascular disease, a reduction in the conductivity or structural changes in the myocardium of the heart contribute to a reduction in the complexity of the cardiac system. Consequently, the complexity of the cardiac system is reduced. After that, the support vector machine (SVM) classifier is adopted to evaluate the performance of the proposed approach. The accuracy of 94.1% and 95.58% between healthy and myocardial infarction on two datasets. Therefore, this method can be adopted for the development of a noninvasive and low-cost clinical prognostic system to identify heart-related diseases and detect hidden state changes in the cardiac system.

With the popularity of social networking sites, enterprises start to establish their own brand communities to manage and maintain customer relationships. Consumer stickiness is regarded as one of the critical determinants for the success of a brand community. Enhancing consumers' stickiness to online communities can lead to repurchase behavior and positive word-of-mouth and thereby increase sales volume and customer recruitment. This study endeavors to explore the antecedents of consumers' stickiness to a SNS-based online brand community from the aspects of enterprises and consumers. Data were collected through online questionnaires conducted on Do-Survey website with a hyperlink posted on the PTT, the largest BBS website of Taiwan. After excluding non-usable data, the final sample size was 516. The results indicated that information quality, perceived value, and community identification have positive effects on consumers' stickiness to online brand communities. Moreover, stickiness to online brand communities has positive impacts on customer loyalty.