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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 4699-4701 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Recently, the wavelet analysis is being applied to the various fields, such as image data compression in informatics and spectrum analysis of the electrocardiogram. In the present article, we propose the two approaches, employing the wavelet analysis for the human heart diagnosis. One is the data base approach, and the other is an inverse approach searching for the magnetic field source of the human heart. The data base approach is an application of the data compression to the magnetocardiogram. Also, the magnetic field source searching is an application of the spectrum analysis to the magnetocardiogram. The results reveal that the data base approach makes it possible to identify the normal or abnormal heart, and the magnetic field source search is capable of estimating the current distribution of a distinct heart. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Melbourne, Australia : Blackwell Science Pty
    Clinical and experimental pharmacology and physiology 28 (2001), S. 0 
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. Extracts of Ginkgo biloba (EGb) and ginsenosides (GS) have been reported to induce vasorelaxation. In the present study, the role of K+ channels in the action of EGb and GS to activate nitric oxide synthase (NOS) activity was investigated in cultured endothelial cells.2. Nitric oxide synthase activity of cultured endothelial cells detected by the reduced nicotinamide adenine dinucleotide phosphate (NADPH) histochemistry method was significantly increased after treatment with 20 μg/mL EGb or 40 μg/mL GS plus 10 mmol/L L-arginine. The effect was completely abolished by the addition of 0.5 μmol/L Nω-nitro-L-arginine, an inhibitor of NOS, to the incubation medium and partially inhibited by 10 μmol/L tetraethylammonium (TEA), an inhibitor of Ca2+-activated K+ (KCa) channels.3. Application of EGb to the intracellular surface of excised inside-out patches activated K+ channels in a concentration-dependent manner in the concentration range 1–100 μg/mL. Channel activity was also activated by application of GS at concentrations ranging from 1 to 300 μg/mL. The modulation of channel activity was inhibited by 0.5 mmol/L TEA but not by 0.5 mmol/L glibenclamide, an inhibitor of ATP-sensitive K+ channels.4. Thus, in cultured endothelial cells, the increase in NOS activity induced by EGb or GS depends on the activity of KCa channels. These compounds may regulate nitric oxide release by changing the cell membrane potential in vascular endothelial cells.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Helicobacter pylori infection is involved in the formation of chronic peptic ulcer. However, a previously reported hypothesis concerning the involvement of central autonomic nervous disorder in this condition cannot be ruled out.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To use spectrum analysis of heart rate viability to examine autonomic nervous activity before and after H. pylori eradication.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Twenty patients with chronic duodenal ulcer (duodenal ulcer group) and 20 age-matched normal adults (N group). In both groups, 24-h Holter electrocardiograms (ECGs) were recorded and spectrum analysis of heartrate variability was performed. In the duodenal ulcer group, Holter ECG was recorded before and after H. pylori eradication.〈section xml:id="abs1-4"〉〈title type="main"〉Results:In the N group, analysis of heart rate variability showed that high frequency (HF) power, an index of parasympathetic activity, was high at night, while the low frequency (LF)/HF ratio, an index of sympathetic function, was high during the daytime. In the duodenal ulcer group, HF power was higher at night than during the daytime, showing a similar pattern to the N group, but the power value was higher than in the N group (P 〈 0.05). In the duodenal ulcer group, LF/HF at night was significantly higher than that of the N group. In addition, in the duodenal ulcer group, autonomic activity after H. pylori eradication did not differ significantly from that before H. pylori eradication.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:In patients with chronic peptic ulcer, both sympatheticotonia and parasympatheticotonia may occur at night, and this abnormality in autonomic nervous activity may cause increased gastric acid secretion and gastric mucosal vasoconstriction. Abnormalities in autonomic activity persist even after H. pylori eradication, suggesting that they may be an independent risk factor in the formation of chronic peptic ulcer in addition to H. pylori infection.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: The relationship between 1/f fluctuation of the heart rate variability and Helicobacter pylori infection was evaluated, in order to clarify whether autonomic nervous dysfunction is a necessary condition for chronic peptic ulcer formation. Methods: The subjects were 11 patients with recurrent chronic peptic ulcer and 20 age-matched normal subjects. Holter ECGs were recorded over 24 h, and the 1/f –x fluctuation of the heart rate was computed. The 1/f –x fluctuation of the heart rate is a novel index of autonomic function that has been shown to reflect a patient's pleasant mood. For 1/f –x fluctuation, the slope of the regression line (–x) was determined and cosine fitting of the absolute slope of the regression line over a 24-h period was performed. Results: For the normal group, the absolute slope of the regression line during daytime and night-time were 0.53 ± 0.16 and 1.05 ± 0.18, respectively. For the peptic ulcer group, the corresponding values during daytime and night-time were 0.94 ± 0.15 and 1.84 ± 0.18, respectively. The mean value of the cosine curve was 0.76 ± 0.23 in the normal group and 1.12 ± 0.25 in the peptic ulcer group. Thus, these values were significantly higher for the latter group than for the former group (P 〈 0.05). No statistically significant difference in H. pylori infection between the two groups was observed. Conclusions: Autonomic nervous dysfunction as well as H. pylori infection appears to be a necessary condition for chronic peptic ulcer formation.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background : Nitrates decrease the tone of the lower oesophageal sphincter, and may thus induce gastro-oesophageal reflux.Aim : In the present study, we evaluated electrogastrographic changes and heart-rate variability before and after the administration of nitrates.Methods : In 15 patients with chest pain treated with nitrates, electrocardiography and percutaneous electrogastrography were performed before and after administration of nitrates. Autonomic nervous system function was evaluated by spectral analysis of heart-rate variability and serial changes in low frequency and high frequency power, and the low frequency/high frequency ratio were compared. Electrogastrograms were analysed by obtaining peak power amplitudes and their dominant frequencies.Results : After the administration of nitrates (isosorbide dinitrate), high frequency power, an index of parasympathetic nervous activity, was significantly decreased, whereas the low frequency/high frequency ratio, an index of sympathetic nervous activity, was significantly increased. The mean peak amplitude of the electrogastrogram significantly increased postprandially both before and after treatment. After isosorbide dinitrate treatment, however, mean peak amplitudes after a meal were significantly lower than those obtained before treatment. The mean dominant frequency of the electrogastrogram did not vary before and after treatment.Conclusions : The present study suggests that nitrates inhibit gastrointestinal motility by decreasing autonomic nervous activity.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism 487 (1977), S. 422-430 
    ISSN: 0005-2760
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 193 (1993), S. 240-247 
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 190 (1993), S. 263-269 
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    FEBS Letters 345 (1994), S. 47-49 
    ISSN: 0014-5793
    Keywords: ATP-sensitive K^+ channel ; Endothelium-derived hyperpolarizing factor ; Endotoxin ; Nitric oxide
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    FEBS Letters 255 (1989), S. 281-284 
    ISSN: 0014-5793
    Keywords: Ca^2^+, external ; K channel ; Smooth muscle ; Vasodilator
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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