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  • 1
    ISSN: 0392-6737
    Keywords: Biophysical instrumentation and techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto È stato usato un apparato di misurazione a un fotone per misurare la chemiluminescenza emessa durante la perossidazione dei fosfolipidi della membrana cellulare di un cuore di ratto isolato e perfuso sottoposto ad uno stress perossidativo. Lo stress perossidativo è stato ottenuto aggiungendo idroperossidi al liquido di perfusione. I differenti idroperossidi usati hanno prodotto tipiche evoluzioni temporali di chemi-luminescenza altamente riproducibili. La disponibilità di ossigeno influenza fortemente l'intensità e la cinetica di emissione della chemiluminescenza. Nell'àmbito di uno studio sull'effetto di differenti idroperossidi sul cuore di ratto isolato e perfuso, la misura della chemiluminescenza si è dimostrata un interessante e promettente strumento per il monitoraggio in continuo dei danni perossidativi nelle membrane biologiche. La sensibilità di questo metodo per la valutazione della perossidazione dei fosfolipidi delle biomembrane è circa dieci volte maggiore rispetto agli ordinari metodi di chimica analitica.
    Abstract: Резюме В этой статъе описывается аппаратура для ретистрации отделъных фотонов для непрерывного мониторнта улътраслабой хемилюминесценции, испус-каемой во время пероксидации фосфолипидов клеточной мембраны изолированного и перфузированного сердца крысы. В частности, аппаратура для ретистрации отделъ-ных фотонов исполъзуется для оценки напряжениь, индуцированных в сердце при добавлении тидроперекиси в пербузирующую жидкостъ. для этого исполъзуутся различные тидропероксиды, которые дают типичные временные эволюции улътса-слабой хемиюминесценции. Также получается, что наличие кислорода силъно влияет на интенсивиостъ и кинетику улътраслабои хемилюминесценции. Показывается, что улътраслабая хемилюминесценция представляет оченъ интересный и перспективный инструмент для мониторинга пероксидативных повреждений биологических мембран. Чувствителъностъ этого метода для пценки пероксидации босболинидов биомембран почти в десятъ раз выше, чем обычнын методов аналитической химии.
    Notes: Summary This paper describes the use of a single-photon counting apparatus (SPCA) for the continuous monitoring of the ultraweak chemiluminescence (UWC) emitted by isolated and perfused rat hearts and deriving from phospholipid peroxydation. Specifically the SPCA was used to assess the peroxidative stress induced in the heart by the addition of an hydroperoxide to the perfusing medium. To this purpose, different hydroperoxides were used and each one produced a tipical and highly reliable temporal evolution of UWC. It was also found that the oxygen availability strongly influences the intensity and the kinetic of the UWC emission. UWC was proved to be a very interesting and promising tool for monitoring the peroxidative damage of biological membranes, both because it makes a continuous assessment possible and because the sensitivity of this method is approximately ten times greater than usual analytical chemistry methods.
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  • 2
    ISSN: 0167-4889
    Keywords: (Rat heart) ; Chemiluminescence ; Glutathione depletion ; Lipid peroxidation
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0167-4889
    Keywords: (Heart) ; Chemiluminescence ; Hydroperoxide
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1435-1803
    Keywords: regional myocardial metabolish ; regional myocardial flow ; autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1435-1803
    Keywords: myocardial mitochondria ; palmitic acid oxidation rate ; pyruvic acid oxidation rate ; Krebs cycle enzymes ; beta-oxidation enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Mitochondria were prepared from the subendocardial and subepicardial layers of the canine left ventricle. The oxidation rates of palmitate, palmitoyl carnitine and pyruvate of the mitochondria obtained from the two cardiac layers were measured. The cytochrome content and the specific activities of different beta oxidation and Krebs cycle enzymes were also measured in the two mitochondrial populations. Mitochondria isolated from the ENDO layer showed significantly higher oxidation rates than mitochondria from the EPI layer for all the three substrates. No statistically significant differences in cytochrome c+c1 and a+a3 content were found in mitochondria isolated from the two regions. No significant transmural differences were found in fatty acyl CoA, L-3-hydroxy fatty acyl CoA, succinic and malic dehydrogenase specific activities, whilst isocitric dehydrogenase (NADP) specific activity was significantly higher in mitochondria isolated from the inner layer. In conclusion, the mitochondria isolated from the inner left ventricular layer of the canine heart show a higher oxidative capacity than subepicardial mitochondria. This difference could partly be explained by the higher specific activity of isocitric dehydrogenase in this layer. These properties of subendocardial mitochondria could represent a metabolic support for the greater contractile performance of this layer.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Basic research in cardiology 90 (1995), S. 285-287 
    ISSN: 1435-1803
    Keywords: Coronary artery disease ; myocardial ischemia ; ventricular dysfunction ; positron emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1435-1803
    Keywords: Afferents ; cardio-cardiac reflex ; deoxyglucoseuptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study was to evaluate the effect of autonomic reflexes as initiated by stimulation of the right recurrent cardiopulmonary nerve afferent axons on myocardial deoxyglucose uptake and to determine how such uptake can be modified by selective neural ablation. The afferent axon in the right recurrent cardiopulmonary nerve was stimulated 30 s/min for 1 h in five anesthetized open-chest dogs in which 14-C labeled deoxyglucose was i.v. injected at the beginning of the stimulation period. Three additional sham-operated dogs served as neurally intact controls. Concentrations of label and glucose were measured in plasma. Regional myocardial deoxyglucose concentration was measured by quantitative autoradiography, following the calibration of plasma samples autoradiographic density by β counting. Stimulation of right recurrent cardiopulmonary nerve afferent axons in the intact nervous system preparation did not significantly enhance deoxyglucose uptake as compared to neurally intact controls. When the right cervical vagosympathetic complex was cut a similar uptake was observed. Following decentralization of the right stellate ganglion, uptake was markedly reduced, as well as when the right cervical vagosympathetic was cut and the right stellate ganglion decentralized. Conclusions: Activation of afferent axons from cardiopulmonary receptors does not alter myocardial deoxyglucose uptake. Reducton in uptake occurs following unilateral stellate ganglion decentralization.
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  • 8
    ISSN: 1435-1803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Conclusion The results of the PET studies reported in Table 1 and Table 2 demonstrate that on average resting myocardial blood flow in hibernating segments is within the range of flows measured in normal subjects and on average is only slightly reduced (approximately by 15–20%) compared with normal remote regions in the same patients. Direct measurements in conscious animals have demonstrated that a 20% reduction in transmural flow (which in dogs involves no decrease in subepicardial flow) accounts for less than a 40% reduction in function (5) which is far less severe than the functional impairment seen in most patients. Therefore, some other phenomenon must account for the severe ventricular dysfunction observed in most patients with hibernating myocardium. In patients with coronary artery disease, coronary flow reserve decreases as the degree of stenosis is increased and is abolished for stenoses equal to 80% or more of the luminal diameter. Under these circumstances, any increase in cardiac workload above baseline conditions cannot be met by an adequate increase in myocardial blood flow, leading to myocardial ischemia. In their pioneering study, Vanoverschelde et al. (12) have demonstrated that in patients with proximal occlusion of the left anterior descending (LAD) coronary artery and normal resting myocardial blood flow, the only discriminant between those with normal wall motion and those with severe dysfunction in the territory subtended by the LAD was the inability to increase flow following dipyridamole administration in the latter group They conclude (12) that “in these patients, impaired function probably results from repetitive episodes of ischemia with a persistent stunning effect ...”.
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