33 research outputs found

    Endothelial Function as a Possible Significant Determinant of Cardiac Function during Exercise in Patients with Structural Heart Disease

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    This study was investigated the role that endothelial function and systemic vascular resistance (SVR) play in determining cardiac function reserve during exercise by a new ambulatory radionuclide monitoring system (VEST) in patients with heart disease. The study population consisted of 32 patients. The patients had cardiopulmonary stress testing using the treadmill Ramp protocol and the VEST. The anaerobic threshold (AT) was autodetermined using the V-slope method. The SVR was calculated by determining the mean blood pressure/cardiac output. Flow-mediated vasodilation (FMD) was measured in the brachial artery to evaluate endotheilial function. FMD and the percent change f'rom rest to AT in SVR correlated with those from rest to AT in ejection fraction and peak ejection ratio by VEST, respectively. Our findings suggest that FMD in the brachial artery and the SVR determined by VEST in patients with heart disease can possibly reflect cardiac function reserve during aerobic exercise

    Detailed study of the ac susceptibility of Sr2RuO4 in oriented magnetic fields

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    We have investigated the ac susceptibility of the spin triplet superconductor Sr2_2RuO4_4 as a function of magnetic field in various directions at temperatures down to 60 mK. We have focused on the in-plane field configuration (polar angle θ90\theta \simeq 90^{\circ}), which is a prerequisite for inducing multiple superconducting phases in Sr2_2RuO4_4. We have found that the previous attribution of a pronounced feature in the ac susceptibility to the second superconducting transition itself is not in accord with recent measurements of the thermal conductivity or of the specific heat. We propose that the pronounced feature is a consequence of additional involvement of vortex pinning originating from the second superconducting transition.Comment: Accepted for publication in Phys. Rev.

    Interface superconductivity in the eutectic Sr2RuO4-Ru: 3-K phase of Sr2RuO4

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    The eutectic system Sr2RuO4-Ru is referred to as the 3-K phase of the spin-triplet supeconductor Sr2RuO4 because of its enhanced superconducting transition temperature Tc of ~3 K. We have investigated the field-temperature (H-T) phase diagram of the 3-K phase for fields parallel and perpendicular to the ab-plane of Sr2RuO4, using out-of-plane resistivity measurements. We have found an upturn curvature in the Hc2(T) curve for H // c, and a rather gradual temperature dependence of Hc2 close to Tc for both H // ab and H // c. We have also investigated the dependence of Hc2 on the angle between the field and the ab-plane at several temperatures. Fitting the Ginzburg-Landau effective-mass model apparently fails to reproduce the angle dependence, particularly near H // c and at low temperatures. We propose that all of these charecteric features can be explained, at least in a qualitative fashion, on the basis of a theory by Sigrist and Monien that assumes surface superconductivity with a two-component order parameter occurring at the interface between Sr2RuO4 and Ru inclusions. This provides evidence of the chiral state postulated for the 1.5-K phase by several experiments.Comment: 7 pages and 5 figs; accepted for publication in Phys. Rev.

    A Posteriori Conditional General Expected Value with Product-product Operation in Nondeterministic Decision Processes

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    We introduce the a posteriori conditional general expected value with product-product operation in finite horizon discrete nondeterministic decision processes. The term nondeterministic is a type of transition systems. It means that a single state yields more than one state in the next stage. In this paper, we derive the recursive equations by using invariant imbedding technique

    The Null technique as a novel, potential first-line method of device delivery for complicated lesions during percutaneous coronary intervention

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    Aim: During percutaneous coronary intervention (PCI), complicated lesions in the target coronary artery often hinder device delivery. Fluid lubricants have commonly been used to reduce friction between adjacent solid materials in manufacturing, thus achieving smoother action. This ex vivo experimental study examined whether a contrast medium could function as a fluid lubricant during PCI. Methods and results: We used two different coronary artery lesion models with distinct complexities made from silicon. Each model was fit into the ex vivo PCI-simulation system. This ex vivo laboratory equipment consisted of ordinary PCI instruments and an aorta model from the Valsalva sinus to the descending aorta. A Wolverine™ cutting balloon catheter was advanced through each lesion model via a guide catheter set into the system. The maximum force required to push the catheter through the lesion models was measured while the vessel system was filled with either normal saline or contrast medium. The maximum force required was significantly lower with the contrast medium (1.38 ± 0.21 N in the normal-saline condition vs. 0.92 ± 0.05 N in the contrast-medium condition in the lesion model A, p < 0.001; 1.30 ± 0.07 N in the normal-saline condition vs. 1.14 ± 0.04 N in the contrast-medium condition in the lesion model B, p < 0.001). Conclusions: The contrast medium for vessel system filling reduced the force required to push the devices through the lesion models. This contrast medium represents a potential candidate for a liquid lubricant to facilitate device delivery for complicated coronary lesions

    Surgical treatment of HCC in a patient with lamivudine-resistant hepatitis B cirrhosis with adefovir dipivoxil

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    We describe a 77-year-old woman with chronic hepatitis B who became resistant to lamivudine. She was started on adefovir (10 mg daily) while still continuing lamivudine therapy. Four mo later her liver function improved and serum Hepatitis B virus (HBV)-DNA level became undetectable. Three years after the start of additional adefovir treatment, hepatocellular carcinoma (HCC) was detected and the patient underwent a successful hepatectomy. Our findings suggest that the addition of adefovir to ongoing lamivudine therapy cannot completely suppress hepatocarcinogenesis, but is useful for improving liver function in patients with lamivudine-resistant HBV-related cirrhosis, allowing HCC surgery
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