Is paroxysmal supraventricular tachycardia truly benign? Insightful association between PSVT and stroke from a National Inpatient Database Study.

BACKGROUND: Atrial fibrillation and flutter are well-known causes of stroke. Whether other atrial arrhythmias categorized as paroxysmal supraventricular tachycardia (PSVT) are associated with stroke is less clear. We aimed to evaluate the association of PSVT with ischemic and embolic stroke and its impact on short-term outcomes in hospitalized stroke patients. METHODS: National Inpatient Sample database of the USA was used to assess the association of PSVT with ischemic stroke. Atrial fibrillation and flutter were excluded to minimize the confounding effects. The association of PSVT with stroke was evaluated using univariate and multivariate analysis. Subgroup analyses by gender, age, and stroke type were also performed. RESULTS: PSVT was associated with increased odds of overall ischemic stroke in univariate [OR 1.18 (95% CI 1.09-1.27) p < 0.001] analysis. No such association was observed in multivariate analysis (OR 1.06 (95% CI 0.98-1.14) p = 0.1) or with subgroup analysis by gender and age. However, PSVT was associated with embolic stroke in both univariate (OR 2.01 (95%CI 1.67-2.43, p < 0.001) and multivariate analysis (OR 1.7 (95%CI 1.4-2.14) p < 0.001) as well as in subgroup analyses by gender and age. Furthermore, the presence of PSVT was associated with increased mortality in embolic stroke (OR 4.11, CI 2.29 to 7.39, p < 0.001) and increased total hospital cost and length of hospital stay in all stroke types. CONCLUSIONS: PSVT is independently associated with higher prevalence of embolic stroke but not with overall ischemic stroke. Patients with embolic stroke in the presence of PSVT have worse in-hospital outcomes with increased mortality.

Properties of synthetic spider silk fibers based on Argiope aurantia MaSp2.

Spiders have evolved a complex system of silk producing glands. Each of the glands produces silk with strength and elasticity tailored to its biological purpose. Sequence analysis of the major ampullate silk reveals four highly conserved concatenated blocks of amino acids: (GA) n , A n , GPGXX, and GGX. While the GPGXX motif, which has been hypothesized to be responsible for the extensibility of the fiber, displays natural variation in its precise sequence arrangement and content, correlating these differences with particular fiber properties has been difficult. Three genetic constructs based on the Argiope aurantia sequence were engineered to progressively increase the number of GPGXX repeats in a head-to-tail assembly prior to interruption by another motif. Circular dichroism and Fourier transform infrared spectroscopy of synthetic spider silk spin dopes show secondary structures that correspond to an increase in the repeat number of GPGXX regions and an increase in the extensibility of synthetically spun recombinant fibers.

Wnt signaling and cardiac differentiation.

The Wnt family of secreted glycoproteins participates in a wide array of biological processes, including cellular differentiation, proliferation, survival, apoptosis, adhesion, angiogenesis, hypertrophy, and aging. The canonical Wnt signaling primarily utilizes ß-catenin-mediated activation of transcription, while the noncanonical mechanisms involve a calcium-dependent protein kinase C-mediated Wnt/Ca(2+) pathway and a dishevelled-dependent c-Jun N-terminal kinase-mediated planar cell polarity pathway. Although both canonical and noncanonical Wnts have been implicated in cardiac specification, morphogenesis, and differentiation; the molecular events remain unclear and often depend on the cell type and biological context. In this regard, growing evidence indicates that Wnt11 is able to induce cardiogenesis not only during embryonic development but also in adult cells. The cardiogenic properties of Wnt11 may prove useful for preprogramming adult stem cells before myocardial transplantation. Further, elucidation of the molecular steps in Wnt11-induced cardiac differentiation will be necessary to enhance the outcomes of cardiac cell therapy.