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31.
William J. Engellenner Lloyd Rozboril Valerie P. Perdue Richard G. Burright Peter J. Donovick 《Physiology & behavior》1982,28(1):177-179
An inexpensive and easily constructed metabolic cage for mice is presented. This apparatus can reliably monitor food and fluid consumption, as well as urine and fecal output, in a relatively non-intrusive manner. 相似文献
32.
Stringer WW Whipp BJ Wasserman K Pórszász J Christenson P French WJ 《European journal of applied physiology》2005,93(5-6):634-639
Published literature asserts that cardiac output (=O2×1/C(a-v)O2) increases as a linear function of oxygen uptake with a slope of approximately 5–6 during constant work rate exercise. However, we have previously demonstrated that C(a-v)O2 has a linear relationship as a function of O2 during progressively increasing work rate incremental exercise. Therefore, we hypothesized that may indeed have a non-linear relationship with respect to O2 during incremental, non-steady state exercise. To investigate this hypothesis, we performed five maximal progressive work rate exercise studies in healthy human subjects. was determined every minute during exercise using measured breath-by-breath O2, and arterial and pulmonary artery measurements of PO2, hemoglobin saturation, and content. was plotted as a function of O2 and the linear and non-linear (first order exponential and hyperbolic) fits determined for each subject. Tests for linearity were performed by assessing the significance of the quadratic terms added to the linear relation using least squares estimation in linear regression. Linearity was inadequate in all cases (group P<0.0001). We conclude that cardiac output is a non-linear function of O2 during ramp-incremental exercise; the pattern of non-linearity suggests that while the kinetics of are faster than those of O2 they progressively slow as work rate (and O2) increases. 相似文献
33.
P. H. Langsjoen K. Folkers K. Lyson K. Muratsu T. Lyson P. Langsjoen 《Journal of molecular medicine (Berlin, Germany)》1988,66(13):583-590
Summary Coenzyme Q10 (CoQ10) is indispensable in mitochondrial bioenergetics and for human life to exist. 88/115 patients completed a trial of therapy with CoQ10 for cardiomyopathy. Patients were selected on the basis of clinical criteria,X-rays, electrocardiograms, echocardiography, and coronary angiography. Responses were monitored by ejection fractions, cardiac output, and improvements in functional classifications (NYHA). Of the 88 patients 75%–85% showed statistically significant increases in two monitored cardiac parameters. Patients with the lowest ejection fractions (approx. 10%–30%) showed the highest increases (115%–210%) and those with higher ejection fractions (50%–80%) showed increases of approx. 10%–25% on therapy. By functional classification, 17/21 in class IV, 52/62 in class III, and 4/5 in class II improved to lower classes. Clinical responses appeared over variable times, and are presumably based on mechanisms of DNA-RNA-protein synthesis of apoenzymes which restore levels of CoQ10 enzymes in a deficiency state. 10/21 (48%) of patients in class IV, 26/62 (42%) in class III, and 2/5 (40%) in class II had exceptionally low control blood levels of CoQ10. Clinical responses on therapy with CoQ10 appear maximal with blood levels of approx. 2.5 µg CoQ10/ml and higher during therapy.Abbreviations CHF
Congestive heart failure
- CO
Cardiac output
- CoQ10
Coenzyme Q10
- EF
Ejection fraction
- IC
Impedance cardiography
- NYHA
New York Heart Association
- STI
Systolic time interval 相似文献
34.
There is a prevailing hypothesis that an acute change in the fraction of oxygen in inspired air (F
IO2) has no effect on maximal cardiac output (
), although maximal oxygen uptake (
) and exercise performance do vary along with F
IO2. We tested this hypothesis in six endurance athletes during progressive cycle ergometer exercise in conditions of hypoxia
(F
IO2=0.150), normoxia (F
IO2=0.209) and hyperoxia (F
IO2=0.320). As expected,
decreased in hypoxia [mean (SD) 3.58 (0.45) l·min–1, P<0.05] and increased in hyperoxia [5.17 (0.34) l·min–1, P<0.05] in comparison with normoxia [4.55 (0.32) l·min–1]. Similarly, maximal power (
) decreased in hypoxia [334 (41) W, P<0.05] and tended to increase in hyperoxia [404 (58) W] in comparison with normoxia [383 (46) W]. Contrary to the hypothesis,
was 25.99 (3.37) l·min–1 in hypoxia (P<0.05 compared to normoxia and hyperoxia), 28.51 (2.36) l·min–1 in normoxia and 30.13 (2.06) l·min–1 in hyperoxia. Our results can be interpreted to indicate that (1) the reduction in
in acute hypoxia is explained both by the narrowing of the arterio-venous oxygen difference and reduced
, (2) reduced
in acute hypoxia may be beneficial by preventing a further decrease in pulmonary and peripheral oxygen diffusion, and (3)
reduced
and
in acute hypoxia may be the result rather than the cause of the reduced
and skeletal muscle recruitment, thus supporting the existence of a central governor.
Electronic Publication 相似文献
35.
Acute hypervolemia induced in experiments on dogs by infusion of dextran, did not produce decompensation of the circulation in animals whose cardiac output was sharply depressed in the postresuscitation period after circulatory arrest lasting 15 min. The increase in the venous return and change in the conditions of the peripheral circulation as a result of dextran administration temporarily increased the central venous pressure, caused a lasting increase in the arterial pressure, cardiac output, stroke volume, work of the left ventricle, and total oxygen consumption by the body, and lowered the peripheral vascular resistance. In model experiments on dogs subjected to isolated compression ischemia of the brain for 20 min, a low cardiac output syndrome also developed.Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Fedorov.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 787–789, July, 1976. 相似文献
36.
本文研究了大鼠慢性高输出量型心功能不全发展过程中心室舒,缩功能和顺应性的变化规律及其与心泵功能的关系。疾病模型采用动静脉造瘘(ACF)加单侧肾动脉缩窄(RAS)的方法建立。本实验中,全部ACF+RAS大鼠均呈现出慢性高输出量型心功能不全的特征,在静息状态下心脏指数(CI)显著升高,而心泵贮备功能(CORF)却不同程度地降低。结果表明:随心泵功能的恶化,心室的舒、缩功能进行性降低,心室的舒张顺应性显著升高,心室的舒,缩性能和顺应性在心功能不全发展的不同阶段对心泵功能所起的作用不同。 相似文献
37.
Victor A. Convertino Karen L. Mathes Mary L. Lasley Clare M. Tomaselli Mary A. B. Frey G. Wyckliffe Hoffler 《European journal of applied physiology》1993,67(6):492-498
Hemodynamic, cardiac, and hormonal responses to lower-body negative pressure (LBNP) were examined in 24 healthy men to test the hypothesis that responsiveness of reflex control of blood pressure during orthostatic challenge is associated with interactions between strength and aerobic power. Subjects underwent treadmill tests to determine peak oxygen uptake (
O2max) and isokinetic dynamometer tests to determine knee extensor strength. Based on predetermined criteria, subjects were classified into one of four fitness profiles of six subjects each, matched for age, height, and body mass: (a) low strength/average aerobic fitness, (b) low strength/high aerobic fitness, (c) high strength/average aerobic fitness, and (d) high strength/high aerobic fitness. Following 90 min of 0.11 rad (6°) head-down tilt (HDT), each subject underwent graded LBNP to –6.7 kPa or presyncope, with maximal duration 15 min, while hemodynamic, cardiac, and hormonal responses were measured. All groups exhibited typical hemodynamic, hormonal, and fluid shift responses during LBNP, with no intergroup differences between high and low strength characteristics. Subjects with high aerobic power exhibited greater (P < 0.05) stroke volume and lower (P < 0.05) heart rate, vascular peripheral resistance, and mean arterial pressure during rest, HDT, and LBNP. Seven subjects, distributed among the four fitness profiles, became presyncopal. These subjects showed greatest reduction in mean arterial pressure during LBNP, had greater elevations in vasopressin, and lesser increases in heart rate and peripheral resistance. Neither
O2max nor leg strength were associated with fall in arterial pressure or with syncopal episodes. We conclude that interactions between aerobic and strength fitness characteristics do not influence responses to LBNP challenge. 相似文献
38.
For planning or co-ordinating health services it is necessary to have reference points for evaluating similar departments
in which homogeneous or equivalent activities are carried out. It is also necessary to consider the cost/benefit of the services.
The paper presents several new indices of performance which may be applied to this problem and which enable quantitative comparisons
to be made between hospitals and between departments. These indices include assessment of electrical hazards and service ability
of equipment as well as the ratio of technical support staff to inpatient stay. The indices have been evaluated in a few large
hospitals and found to be an effective management tool. 相似文献
39.
Radiocardiography was used to measure cardiac output, stroke volume and left ventricular ejection fraction at rest and during muscular exercise in relation with age in 148 healthy subjects (age range: 6–78 years). A clear dependence of these parameters on age was found. The mean annual decrease at rest was 22±9 ml/min/m2 for cardiac index, 0.22±0.04 ml/m2 for stroke index and 0.0017±0.0003 for left ventricular ejection fraction. Male subjects had significantly (p < 0.001) greater cardiac (9±4%) and stroke indices (11±23%) than females. During submaximal exercise cardiac index increased from 3.5±0.7 l/min/m' to 8.1±1.6 l/min/m2 in male subjects (mean age: 32 years) and from 3.1±0.4 l/min/m2 to 7.2±1.2 l/min/ m2 in female subjects (mean age: 29 years). The corresponding increases in stroke index and left ventricular ejection fraction were: from 52±7 ml/m2 to 62±9 ml/m2. from 46±7 ml/m2 to 51±9 ml/m2 and from 0.66±0.08 to 0.79±0.05 and from 0.64±0.10 to 0.72±0.10. In subjects who were 60 years and older the increases of these parameters during exercise were considerably smaller. 相似文献
40.