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  • 1
    ISSN: 1439-6327
    Keywords: Cycle ergometry ; Myocardial function ; Left ventricular ejection fraction ; Radionuclide ventricular scintigraphy ; Inflection of heart rate/performance curve
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The heart rate/work performance (f c/W) curve is usually S-shaped but a flattening at the top is not always seen. By means of radionuclide ventricular scintigraphy, the left ventricular ejection fraction (LVEF) of 15 sports students was investigated. The behaviour of the f c/W curve during cycle ergometry with increasing exercise intensities was examined. During exercise, the LVEF showed a distinct initial increase reaching roughly constant values at stress levels below-maximum, and sometimes even falling again. The inflections of the f c/W curve and left ventricular ejection fraction/performance curve (LVEFPC) were calculated from a second degree polynomial fit. From this function, the slopes of the tangents at the points of aerobic threshold and maximum performance were calculated together with the differences of the angles as a measure of the f c/W curve and LVEFPC inflections. It follows that the f c/W curve inflection became less pronounced or was even absent altogether when the decrease in LVEF towards the end of the ergometer exercise became more distinct. A significant negative correlation was found between the existence and extent of the f c/W curve inflection and the stress-dependent myocardial function, expressed as the inflection of the LVEFPC (P〈0.01, r=0.673). Thus, it would seem that the absence of a f c/W curve inflection was related to a diminished stress-dependent myocardial function.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 39 (1994), S. 1930-1934 
    ISSN: 1573-2568
    Keywords: Crohn's disease ; anemia ; erythropoietin ; iron ; interleukin-6
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Intestinal blood loss as well as chronic inflammation are regarded as the most important mechanisms in the pathogenesis of anemia in Crohn's disease. In addition, cytokines such as interleukin-6 can suppress erythropoietin production. This study was performed to investigate the importance of iron status, inflammatory activity, and endogenous erythropoietin concentrations for the development of anemia in Crohn's disease. In 49 consecutive patients with Crohn's disease, hemoglobin, inflammatory activity (Crohn's disease activity index, C-reactive protein, α1-acid glycoprotein), iron status (serum iron, transferrin, transferrin saturation, ferritin), and serum erythropoietin levels were studied. Anemic (Hb〈12.0 g/dl;N=16) vs nonanemic patients (Hb≥12 g/dl;N=33) showed reduced iron compartments (eg, ferritin 28.7±12.9 µg/liter vs 63.2±15.0 µg/liter, transferrin saturation 6.2±1.4% vs 11.5±1.3%,P〈0.01) but no differences in inflammatory activity. An inverse correlation between erythropoietin and hemoglobin concentrations was found (r=-0.62;P〈0.001), but the increase in erythropoietin levels was inadequate to the degree of anemia. There was no correlation between erythropoietin and interleukin-6 serum levels. Four of five anemic patients with hemoglobin below 10.5 g/dl and erythropoietin levels within the normal range were treated with parenteral iron (200 mg iron saccharate in 250 ml NaCl, weekly, intravenously). Two of them additionally received recombinant human erythropoietin (150 units/kg, 3× weekly, subcutaneously). After five weeks all patients had a marked increase in hemoglobin. However, the mean increase in erythropoietin-treated patients was 5.0 g/dl compared to 2.0 g/dl in the patients with iron therapy only. No side effects were seen. Our data demonstrate that inadequate erythropoietin production and iron deficiency are pathogenetic factors of anemia in Crohn's disease. The therapeutic management using recombinant human erythropoietin and parenteral iron is reasonable and effective.
    Type of Medium: Electronic Resource
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