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  • 1
    Electronic Resource
    Electronic Resource
    Regional oxygen supply and consumption balance in experimental left ventricular hypertrophy (1990)
    Springer
    Basic research in cardiology 85 (1990), S. 575-584 
    Details
    ISSN: 1435-1803
    Keywords: aortic valvestenosis ; coronaryblood flow ; myocardialO 2 consumption ; cardiachypertrophy ; dog
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study was to determine if the relationship between myocardial O2 supply and O2 consumption was preserved after prolonged pressure overload due to aortic valve stenosis. This was examined in anesthetized open-chest dogs in which the aortic valve was plicated 6 months previously. We measured coronary blood flow with radioactive microspheres and regional small vessel O2 saturation with microspectrophotometry, to obtain O2 supply, and O2 consumption. Regional O2 consumption was calculated as the product of flow and O2 extraction. The left ventricular weight/body weight ratio was 81% greater in the dogs with aortic valve stenosis. There were no hemodynamic differences between the groups except that left ventricular systolic pressure was 38±22 mm Hg greater than aortic in the hypertrophied group. Coronary blood flow did not differ between the control and hypertrophied groups nor were there subepicardial vs subendocardial differences. When maximal coronary flow was determined with chromonar (10 mg/kg), the flow increase was significantly attenuated in the hypertrophied subendocardium (242.1±82.3 (hypertrophy) vs 512.4±204.1 ml·min−1·100 g−1 (control)). There were no significant differences in O2 extraction or O2 consumption/g between control and hypertrophied animals. There was a significantly lower O2 supply/consumption ratio in the subendocardium compared to the subepicardium of both groups. However, the O2 supply/consumption ratio was not decreased by hypertrophy. Thus, despite significant hypertrophy, a loss of flow reserve and a high left ventricular pressure, O2 supply/consumption balance is preserved in valvular aortic stenosis at rest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01907892
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  • 2
    Electronic Resource
    Electronic Resource
    Regional asynchrony of segmental contraction may explain the “oxygen consumption paradox” in stunned myocardium (1994)
    Springer
    Basic research in cardiology 89 (1994), S. 149-162 
    Details
    ISSN: 1435-1803
    Keywords: Myocardial ischemia ; coronary reperfusion ; stunned myocardium ; postischemic dysfunction ; oxygen consumption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Despite apparently depressed function, stunned myocardium maintains oxygen consumption and has the capacity to increase contractility with inotropic stimulation. We hypothesized that during stunning, O2 demand is maintained because regional segment work is performed, but is asynchronous with global left ventricular contraction, and that inotropic stimulation would restore regional work and synchrony. Thirteen open-chest anesthetized dogs were subjected to three left anterior descending (LAD) coronary artery occlusions (10 min) and reperfusions (15 min) to produce regional myocardial stunning. Segment shortening and force development were measured independently and simultaneously in the LAD (experimental) region and circumflex (control) regions. Regional myocardial work was calculated as the integrated product of instantaneous force and shortening, during two periods: 1) over the entire cardiac cycle (Positive Work), and 2) limited to the systolic portion of the cardiac cycle (Systolic Work). Regional myocardial O2 consumption (MVO2) was calculated from regional blood flow (radiolabeled microspheres) and O2 saturation data (microspectrophotometry). Occlusion of the LAD produced a delay in onset of segment shortening in the ischemic region, but not in regional force development. A time delay of 67–81 ms persisted through the three stages of occlusions and reperfusion. Systolic regional work was depressed to a greater extent (924±182 to 149±118 g*mm*min−1) than total positive regional work (1437±337 to 857±174 g*mm*min−1). Regional subepicardial MVO2 in the stunned region was not different than in the control region (7.3±1.5 vs. 6.9±1.4 ml O2*min−1*100 g−1). Local infusion of isoproterenol reversed the delay in regional shortening from 73±7 to 21±8 ms, thereby augmenting systolic work (298%) more than positive work (60%), without a significant increase in MVO2 (7.3±1.5 to 10.5±3.2 ml O2*min−1*100 g−1). It is concluded that myocardial stunning decreases regional systolic work due to regional mechanical asynchrony, while MVO2 is used supported total positive work which was not significantly reduced. Isoproterenol restores regional work by restoring synchrony, without greatly affecting regional MVO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00788734
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  • 3
    Electronic Resource
    Electronic Resource
    Arylvanadium(III)-Verbindungen. VI. Darstellung und Eigenschaften von Lithium-trimesityl-organyl-vanadaten(III) (1980)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 460 (1980), S. 51-55 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arylvanadium (III) Compounds. VI. Preparation and Properties of Lithium Trimesityl organyl VanadatesTrimesityl vanadium reacts with LiR (R = Ph, o-Tol, Dmop, CH3, CPh3) forming complexes Li(thf)4 VMes3R. With Li2C6H4 and Li2C2 the compounds Li2(thf) 8 V(μ-C6H4)Mes6 and Li2(thf)8V(μ-C2)Mes6 are obtained. All compounds are characterized by their thermal, magnetical, and spectral properties.
    Notes: Durch Reaktion von Trimesitylvanadium mit Lithiumorganylen, LiR (R = Ph, o-Tol, Dmop, Me, CPh3)Verwendete Abkürzungen: Bu = n-C4H9; Dmop = 2,6-(CH3O)2C6H3; Me = CH3; Mes = 2,4,6-(CH3)3C6H2; Ph = C6H5; o-Tol = 2-CH3C6H4; thf (THF) = C4H8O., sind Complexe des Typs Li(thf)4 VMes3R zugänglich. Mit geeigneten Dilithiumverbindungen können auch verbrückte Zweiternvanadate wie Li2(thf)8V2-(μ-C6H4)Mes6 und Li2(thf)8V2(μ-C2)Mes6 erhalten werden. Die thermischen, magnetischen und spektralen Eigenschaften dieser neuen Verbindungen werden untersucht.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19804600105
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