1,261 research outputs found

    Reduced systemic vascular resistance is the underlying hemodynamic mechanism in nitrate-stimulated vasovagal syncope during head-up tilt-table test

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    AbstractBackgroundNitroglycerin (NTG) challenge during head-up tilt-table testing (HUTT) is often utilized to determine the etiology of unexplained vascular syncope. However, conflicting results concerning nitrate-induced hemodynamic changes during HUTT have been reported. The purpose of this study was to assess the determinants of presyncopal symptoms during NTG-stimulated HUTT.MethodsWe evaluated 40 patients with suspected vasovagal syncope. Beat-to-beat changes in blood pressure, heart rate (HR), cardiac index (CI), and systemic vascular resistance (SVR) during HUTT were measured with thoracic impedance cardiography and a plethysmographic finger arterial pressure monitoring device.ResultsNone of the 40 patients complained of presyncopal symptoms during passive HUTT. However, after the administration of NTG 28 patients showed presyncopal symptoms (NTG+ group) and the remaining 12 patients did not (NTG– group). HR, CI, and the stroke index did not significantly differ between the two groups, whereas mean arterial pressure and SVR were significantly lower in the NTG+ group.ConclusionsPresyncopal symptoms during NTG-stimulated HUTT are SVR mediated, not cardiac output mediated. This study challenges the conventional idea of a decrease in cardiac output mediated by NTG as the overriding cause of presyncopal symptoms during HUTT

    Micro solid oxide fuel cell fabricated on porous stainless steel: a new strategy for enhanced thermal cycling ability

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    Miniaturized solid oxide fuel cells (micro-SOFCs) are being extensively studied as a promising alternative to Li batteries for next generation portable power. A new micro-SOFC is designed and fabricated which shows enhanced thermal robustness by employing oxide-based thin-film electrode and porous stainless steel (STS) substrate. To deposit gas-tight thin-film electrolyte on STS, nano-porous composite oxide is proposed and applied as a new contact layer on STS. The micro-SOFC fabricated on composite oxide- STS dual layer substrate shows the peak power density of 560 mW cm−2 at 550 °C and maintains this power density during rapid thermal cycles. This cell may be suitable for portable electronic device that requires high power-density and fast thermal cycling.1111Ysciescopu

    The seroprevalence of Japanese encephalitis virus in goats raised in Korea

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    Japanese encephalitis virus (JEV) causes a mosquito-borne viral zoonosis that is becoming increasingly important to public health in east and south Asia. Although JEV is primarily associated with reproductive failure in swine, JEV infection can cause fever and headache in humans and is associated with aseptic meningitis and encephalitis. The exact mode of transmission, including host range and possible source of viral amplification within livestock, is still not completely clear. This study consisted of a serological survey of JEV infection in goats. A total of 804 goat serum samples were collected from 144 farms in Korea between May 2005 and May 2006. The incidence of positive cases was 12.1% (97 out of 804 goats). The seroprevalence of JEV infection in the 144 farms screened was 31.3% (45/144), indicating that JEV infection is frequent in goat farms in Korea. In addition, three districts of Korea (mainly in the southern region) had a higher seroprevalence of JEV compared to other areas. The results suggest that goats could be monitored epidemiologically as a sentinel animal for JEV transmission in Korea

    Intracellular Membrane Association of the Aplysia cAMP Phosphodiesterase Long and Short Forms via Different Targeting Mechanisms

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    Phosphodiesterases (PDEs) play key roles in cAMP compartmentalization, which is required for intracellular signaling processes, through specific subcellular targeting. Previously, we showed that the long and short forms of Aplysia PDE4 (ApPDE4), which are localized to the membranes of distinct subcellular organelles, play key roles in 5-hydroxytryptamineinduced synaptic facilitation in Aplysia sensory and motor synapses. However, the molecular mechanism of the isoform-specific distinct membrane targeting was not clear. In this study, we further investigated the molecular mechanism of the membrane targeting of the ApPDE4 long and short forms. We found that the membrane targeting of the long form was mediated by hydrophobic interactions, mainly via 16 amino acids at the N-terminal region, whereas the short form was targeted solely to the plasma membrane, mainly by nonspecific electrostatic interactions between theirNtermini and the negatively charged lipids such as the phosphatidylinositol polyphosphates PI4P and PI(4,5)P<inf>2</inf>, which are embedded in the inner leaflet of the plasma membrane. Moreover, oligomerization of the long or short form by interaction of their respective upstream conserved region domains, UCR1 and UCR2, enhanced their plasma membrane targeting. These results suggest that the long and short forms of ApPDE4 are distinctly targeted to intracellular membranes through their direct association with the membranes via hydrophobic and electrostatic interactions, respectively. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.1

    Polyneuropathy Associated with IgA Paraproteinemia and Amyloidosis: A Case Report and Literature Review

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    Paraproteinemia potentially causes peripheral neuropathy via an unknown underlying pathogenetic mechanism. We report a case of pathologically proven amyloid neuropathy with AL amyloidosis with an IgA kappa light chain, which was initially diagnosed as neuropathy associated with monoclonal gammopathy of undetermined significance. This case indicates that in cases of neuropathy with paraproteinemia, the other potential causes should be excluded by appropriate means, especially pathological evaluations

    Primary Cardiac Angiosarcoma Presenting With Cardiac Tamponade

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    Primary cardiac angiosarcoma is a very rare disease with a poor prognosis. We report a case of a patient with a primary cardiac angiosarcoma who presented with cardiac tamponade; the angiosarcoma was successfully resected surgically
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