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  • 1
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The effects of ventricular pacing on left ventricular (LV) dynamic geometry, function, and myocardial oxygen consumption (MVO2) were measured in 12 conscious dogs using sonomicrometry, micromanometry, ultrasonic flow probes, and oximetry catheters during right atrial (A-) and right ventricular (V-) pacing at 150 beats/mm. Systolic function was quantified using slopes (Mw) and volume-intercepts (Vw) of linear relationships between end-di-astolic volume (EDV) and stroke work (SW) for data obtained during vena caval occlusion. V-pacing shifted SW-EDV relationships downward (Mw decreased from 97 ± 21 to 81 ± 21 Kerg/mL) and to the right (Vw increased from 14 ± 11 to 20 ± 12 mL) in comparison with A-pacing (P 〈 0.05). These functional changes correlated with altered contractile geometry manifest as early shortening in the septal free wall relative to anterior-posterior dimension (increased minor axis mid-wall eccentricity at end-diastole and begin-ejection). Steady-state LV power output decreased from 802 ± 213 mW during A-pacing to 514 ± 170 mW during V-pacing (P 〈 0.05), while MVO2 remained relatively unchanged during V-pacing (10 ± 3 mL O2/min vs 11 ± 3 mL O2/min during A-pacing, P = NS). As a result, overall LV efficiency decreased from 0.24 ± 0.08 during A-pacing to 0.16 ± 0.06 during V-pacing (P 〈 0.05). These data illustrate the impact of V-pacing on dynamic LV geometry and function, including impaired LV work output at all physiological levels of preload. Most importantly, the relationship between LV work output and MVO2 is depressed during V-pacing, emphasizing the interaction between LV mechanics and pump efficiency in intact subjects. As a result, measures taken to restore normal contractile geometry might improve LV efficiency and performance when V-pacing is necessary.
    Type of Medium: Electronic Resource
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  • 2
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    New York : Periodicals Archive Online (PAO)
    Journal of International Affairs. 49:1 (1995:Summer) 255 
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  • 3
    ISSN: 1573-0719
    Keywords: Ageing ; Comparative study ; Epidemiology ; Japanese ; Japanese-Americans ; Osteoporosis ; Risk factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Ethnic Sciences , Sociology
    Notes: Abstract Health characteristics were compared among 1193 Japanese in Hiroshima, and 2306 Japanese-Americans in Hawaii. Japanese women experienced later menarche, earlier menopause, and a shorter interval between menarche and menopause than Japanese-Americans. Japanese men and women were shorter and lighter and the men bad lower body mass index than Japanese-Americans. Differences between populations were also found for the prevalence of artificial menopause, number of live births, lactation period, smoking, and alcohol consumption. Within one or both populations, significant trends with birth year were found for age at menarche, age at menopause, interval between menarche and menopause, lactation period, height, weight, and body mass index, suggesting the existence of cohort effects. Some of these trends may also reflect age-related changes. Environmental factors likely contribute to the differences in physique and reproductive factors, which may explain differences in frequency of osteoporosis, cardiovascular diseases, and cancer between the two populations.
    Type of Medium: Electronic Resource
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