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  • 1
    ISSN: 1432-1041
    Keywords: left ventricular hypertrophy ; diastolic function ; verapamil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We evaluated the effect of verapamil therapy on left ventricular hypertrophy and left ventricular diastolic function in 13 patients with mild to moderate hypertension. Left ventricular hypertrophy was determined by M-mode echocardiographic measurements of interventricular septal thickness (IVST), posterior wall thickness (PWT) and left ventricular mass index (LVMI) both before (T0) and after 3 months (T3) of verapamil therapy. Left ventricular diastolic transmitral flow was measured by pulsed Doppler indices of early (E) and atrial (A) velocity, E/A ratio, total area (Ta), A area (Aa), Aa/Ta ratio, E-pressure half-time (E-PHT), A-pressure half-time (A-PHT) and E-PHT/A-PHT ratio both before and after 3 months of verapamiI therapy. No significant changes occurred in mean heart rate, systolic function or body weight. We conclude that 3 months' therapy with verapamil resulted in an improvement in left ventricular hypertrophy and left ventricular diastolic function and a normalization of blood pressure, without a corresponding deterioration in left ventricular systolic function.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Applied Surface Science 69 (1993), S. 185-192 
    ISSN: 0169-4332
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1439-6327
    Keywords: Key words Exercise ; 1H nuclear magnetic resonance ; 31P nuclear magnetic resonance ; Perfused muscle ; Lactate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated whether localized 1H nuclear magnetic resonance spectroscopy (NMRS) using stimulated echoes (STEAM) with a long mixing time (t m) allowed the suppression of the fat signal and detection of lactate in skeletal muscle. The 1H NMRS sequence was first validated in three isolated and perfused rabbit biceps brachii muscles. Spectra were obtained on a wide-bore spectrometer using a dual-tuned probe (1H and 31P). Death was simulated by ceasing the muscle perfusion, which allowed post-mortem changes to be followed. During and after the simulated death, changes in levels of pH and in content of energy-rich compounds were observed with 31P NMRS. Our results showed an inverse linear relationship between pH and lactate in each of the three rabbits (r = 0.93, P 〈 0.001; r = 0.92, P 〈 0.01; r = 0.89, P 〈 0.01) and a decrease in phosphocreatine and concomitant increase in lactate. We then investigated whether this sequence allowed repeated detection of lactate in human soleus muscle during the recovery between periods of intense exercise (force-velocity test, F-v test). Seven subjects mean age 25.1 (SEM 0.8) years participated in this study. Soleus muscle lactate was detected at rest and for 3 min 30 s of the 5-min recovery between periods using a 2.35-T 40-cm bore magnet spectrometer. Arm venous plasma lactate concentration was measured at rest, during the F-v test when the subject stopped pedalling (S1), and at the end of each 5-min recovery between periods (S2). Results showed that the venous plasma lactate concentration at S1 and S2 increased significantly from the beginning of the F-v test to peak anaerobic power (W an,peak) (P 〈 0.001). The spectra showed that muscle lactate resonance intensity rose markedly when W an,peak was achieved. The muscle lactate resonance intensity plotted as a percentage of the resting value increased significantly at W an,peak compared with submaximal braking forces (P 〈 0.05). We concluded from these results that localized 1H NMRS using STEAM with a long t m allows suppression of the fat signal and repeated detection of lactate on isolated perfused skeletal muscle in animals and between periods of intense exercise in humans.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 66 (1993), S. 461-466 
    ISSN: 1439-6327
    Keywords: Force-velocity test ; Anaerobic power ; Aerobic power ; Maximal oxygen uptake ; Swimmers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of this investigation was to compare anaerobic and aerobic components measured during arm exercise in sprint and middle-distance swimmers and to investigate whether the peak anaerobic power :peak aerobic power ratio (W an, peak :W aer, peak) was related to specialization for the event and to performance. TheW an, peak force at zero velocity (F 0), and velocity at zero-force (ν0),W aer, peak, peak oxygen uptake ( $$\dot V$$ O2peak), and ventilatory threshold (Th v ) were compared during arm exercise tests in sprint (group I,n = 8) and middle-distance (group II,n = 9) competitive male swimmers. Anaerobic indices were estimated by the force-velocity test, an anaerobic test using incremental braking forces; aerobic indices were measured during an incremental aerobic exercise test (30 W · min−1). TheW an, peak andW aer, peak were greater in group I [828 (SEM 70) W; 236 (SEM 12) W] than in group II [678 (SEM 28) W; 230 (SEM 5) W], but the differences were not significant. There were also no significant differences observed between the mean values ofF 0, ν0, $$\dot V$$ O2peak, and Th v . TheW an, peak:W aer, peak, however, was significantly higher in sprint swimmers (t = 3.08,P 〈 0.01). In seven of the swimmers, who had recently performed both the 100-m and 400-m front crawl, a relationship existed between their swim time and theW an, peak:Waer,peak (100m:r = −0.80,P〈0.05 and 400m:r=+0.75,P〈0.05). In conclusion, during arm-crank exercise, we did not observe significant differences in anaerobic and aerobic components between sprint and middle-distance swimmers. However, the results of the present study demonstrated the usefulness of theW an, peak :W aer, peak in the physiological evaluation of swimmers as it reflects the proportion of anaerobic to aerobic systems involved in the supply of energy.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1439-6327
    Keywords: 2-Chloropropionate ; Force-velocity test ; Anaerobic power ; Venous plasma lactate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the effects of a stimulation of pyruvate dehydrogenase (PDH) activity induced by 2-chloropropionate (2-CP) on venous plasma lactate concentration and peak anaerobic power (W an, peak) during periods (6 s) of incremental intense exercise, i.e. a force-velocity (F-ν) test known to induce a marked accumulation of lactate in the blood. TheF-ν test was performed twice by six subjects according to a double-blind randomized crossover protocol: once with placebo and once with 2-CP (43 mg · kg−1 body mass). Blood samples were taken at ingestion of the drug, at 10, 20, and 40 Min into the pretest period, at the end of each period of intense exercise, at the end of each 5-min recovery period, and after completion of theF-ν test at 5, 10, 15, and 30 min. During theF-ν test, venous plasma lactate concentrations with both placebo and 2-CP increased significantly when measured at the end of each period of intense exercise (F = 33.5,P 〈 0.001), and each 5-min recovery period (F = 24.6,P 〈 0.001). Venous plasma lactate concentrations were significantly lower with 2-CP at the end of each recovery period (P 〈 0.01), especially for high braking forces, i.e. 8 kg (P 〈 0.05), 9 kg (P 〈 0.02), and maximal braking force (P 〈 0.05). After completion of theF-ν test, venous plasma lactate concentrations were also significantly lower with 2-CP (P 〈 0.001). The percentage of lactate decrease between 5- and 30-min recovery was significantly higher with 2-CP than with the placebo [59 (SEM 4)% vs 44.6 (SEM 5.5)%,P 〈 0.05]. Furthermore,W an, peak was significantly higher with 2-CP than with the placebo [1016 (SEM 60) W vs 957 (SEM 55) W,P 〈 0.05]. In conclusion, PDH activation by 2-CP attenuated the increase in venous plasma lactate concentration during theF-ν test. Ingestion of 2-CP led to an increasedW an, peak.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 70 (1995), S. 58-65 
    ISSN: 1439-6327
    Keywords: Oxygen uptake ; Lactate ; Wingate test ; Runners
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the aerobic and anaerobic contributions to performance during the Wingate test in sprint and middle-distance runners and whether they were related to the peak aerobic and anaerobic performances determined by two commonly used tests: the force-velocity test and an incremental aerobic exercise test. A group of 14 male competitive runners participated: 7 sprinters, aged 20.7 (SEM 1.3) years, competing in 50, 100 and 200-m events and 7 middle-distance runners, aged 20.0 (SEM 1.0) years, competing in 800, 1,000 and 1,500 m-events. The oxygen uptake ( $$\dot V{\text{O}}_{\text{2}} $$ ) was recorded breath-by-breath during the test (30 s) and during the first 20 s of recovery. Blood samples for venous plasma lactate concentrations were drawn at rest before the start of the test and during the 20-min recovery period. During the Wingate test mean power ( $$\dot W$$ ) was determined and three values of mechanical efficiency, one individual and two arbitrary, 16% and 25%, were used to calculate the contributions of work by aerobic ( $$\dot W$$ aer,ind,16%,25%) and anaerobic ( $$\dot W$$ an,ind,16%,25%) processes. Peak anaerobic power ( $$\dot W$$ an,peak) was estimated by the force-velocity test and maximal aerobic energy expenditure ( $$\dot W$$ aer,peak) was determined during an incremental aerobic exercise test. During the Wingate test, the middle-distance runners had a significantly greater $$\dot V{\text{O}}_{\text{2}} $$ than the sprinters (P 〈 0.001), who had significantly greater venous plasma lactate concentrations (P 〈 0.001). Moreover, $$\dot W$$ aer,ind,16%,25% were also significantly higher (P 〈 0.05) in the middle-distance runners [ $$\dot W$$ aer,ind 45 (SEM 4) % vs 28 (SEM 2) %; $$\dot W$$ aer,16% 30 (SEM 3) % vs 19 (SEM 2) %; $$\dot W$$ aer,25% 46 (SEM 3) % vs 29 (SEM 2)%]; $$\dot W$$ an,ind,16%,25% in the sprint runners (P 〈 0.05) [ $$\dot W$$ an,ind 72 (SEM 3) % vs 55 (SEM 4) %; $$\dot W$$ an,16% 81 (SEM 2) % vs 70 (SEM 3) %; $$\dot W$$ an,25% 71 (SEM 2) % vs 54 (SEM 3) %]. The $$\dot W$$ aer,ind/ $$\dot W$$ aer,peak and $$\dot W$$ × $$\dot W$$ an,ind/ $$\dot W$$ an,peak ratios, however, were not significantly different between the two groups of athletes. These results would indicate that the sprinters and middle-distance runners used preferentially a metabolic system according to their speciality. Nevertheless, under the conditions of its experiment, they seemed to rely on the same percentage of both peak anaerobic and peak aerobic performance for a given exercise task.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1439-6327
    Keywords: Arterio-venous difference ; Lactate ; Force-velocity test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the role of the forearm skeletal muscles in the removal of lactate during repeated periods of short-term intensive leg exercise, i.e. a force-velocity (FV) test known to induce a marked accumulation of lactate in the blood. The leg FV test was performed by seven untrained male subjects. Arterial and venous blood samples for determination of arterial ([la−]a) and venous ([la−]v) plasma lactate concentrations were concomitantly taken at rest before the test, during the FV test at the end of each period of intensive exercise just before the 5-min between-sprint recovery period, and after the completion of the test at 2, 4, 6, 8, 10, 15, and 20 min of the final recovery. The arteriovenous difference in concentration for plasma lactate ([la−]a−v) was determined for each blood sample. During the test, [la−]a and [la−]v increased significantly (P 〈 0.001;P 〈 0.001) with significantly higher values for [la−]a (P 〈 0.001). At the onset of the test, [la−]a−v became positive and increased up to a braking force of 6 kg, correlating significantly with [la−]a (r = 0.61,P 〈 0.001) with power (r = 0.58,P 〈 0.001) during the test. At the end of the test, [la−]a, [la−]v and [la−]a−v decreased (P 〈 0.001;P 〈 0.001;P 〈 0.001 respectively) but were still higher than the basal values after 20-min of passive recovery. In conclusion, forearm skeletal muscles would seem to have been involved in the removal of lactate from the blood during the leg FV test, with an increase in lactate uptake proportional to the increase in plasma lactate concentration and power.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 73 (1996), S. 465-470 
    ISSN: 1439-6327
    Keywords: Endurance-trained ; Sprinter ; Lactate kinetics ; Recovery ; Lactate removal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the effects of passive and partially active recovery on lactate removal after exhausting cycle ergometer exercise in endurance and sprint athletes. A group of 14 men, 7 endurance-trained (ET) and 7 sprint-trained (ST), performed two maximal incremental exercise tests followed by either passive recovery (20 min seated on cycle ergometer followed by 40 min more of seated rest) or partially active recovery [20 min of pedalling at 40% maximal oxygen uptake ( $$\dot V$$ O2max) followed by 40 min of seated rest]. Venous blood samples were drawn at 5 min and 1 min prior to exercise, at the end of exercise, and during recovery at 1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 30, 40, 50, 60 min post-exercise. The time course of changes in lactate concentration during the recovery phases were fitted by a bi-exponential time function to assess the velocity constant of the slowly decreasing component (τ2) expressing the rate of blood lactate removal. The results showed that at the end of maximal exercise and during the 1st min of recovery, ET showed higher blood lactate concentrations than ST. Furthermore, ET reached significantly higher maximal exercise intensities [5.1 (SEM 0.5) W · kg−1 vs 4.0 (SEM 0.3) W · kg−1,P 〈 0.05] and $$\dot V$$ O2max [68.4 (SEM 1.1) ml · kg−1 · min−1 vs 55.5 (SEM 5.1) ml · kg−1 · min−1,P 〈 0.01]. There was no significant difference between the two groups during passive recovery for τ2 During partially active recovery, τ2 was higher than during passive recovery for both groups (P 〈 0.001), but ET recovered faster and sooner than ST (P 〈 0.05). Compared to passive recovery, the τ2 measured during partially active recovery was increased threefold in ET and only 1.5-fold in ST. We concluded that partially active recovery potentiates the enhanced ability to remove blood lactate induced by endurance training.
    Type of Medium: Electronic Resource
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