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  • 1
    Electronic Resource
    Electronic Resource
    A simple operation of a plasma-electrode pockel's cell for the laser megajoules (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 2631-2636 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on a simple way to operate plasma-electrode pockel's cells (PEPC), which are used as large-aperture optical switches in laser drivers for inertial-confinement fusion facilities. In the basic operation of a PEPC, one needs to produce a plasma in each of two gas-filled cells placed on opposite sides of an appropriate crystal plate. Between the resulting highly conductive electrodes, a high-voltage pulse is applied to produce a uniform electric field in the crystal, which then undergoes the Pockel's effect. We have developed a simple PEPC design in which the high-voltage pulse can be directly applied between the gascells without prior ionization of the gas (by a high-current plasma discharge). With reasonable operating parameters, this regime meets the PEPC optical switching requirements for the laser megajoules. In this paper, we present experimental results of this simple regime that strongly simplifies the PEPC concept and improves its reliability. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1446243
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  • 2
    Electronic Resource
    Electronic Resource
    Oxygen Free Radical-Mediated Heart Injury in Animal Models and during Bypass Surgery in Humans Effects of α-Tocopherol (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 570 (1989), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1989.tb14924.x
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  • 3
    Electronic Resource
    Electronic Resource
    Metal-on-Metal Articulation in Total Hip Arthroplasty (2000)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 192-195 (Sept. 2000), p. 975-978 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/45/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.192-195.975.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    The blood perfused isolated heart: characterization of the model (1999)
    Springer
    Basic research in cardiology 94 (1999), S. 215-222 
    Details
    ISSN: 1435-1803
    Keywords: Key words Isolated heart – blood perfusion – myocardial metabolism – pentobarbital anaesthesia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have characterized the aerobic blood-perfused isolated heart model evaluating the hemodynamics and metabolism of both the blood donor animal and the isolated organ. Anaesthesia of the blood donor with sodium pentobarbital (30 mg/kg) increases arterial concentration of non esterified fatty acids (NEFA) from 80 ± 6 to 452 ± 70 μM; p 〈 0.01. Injection of 1.000 U/kg heparin causes a second significant increase from 452 ± 70 to 1012 ± 104 μM; p 〈 0.01. Insertion of the perfusion circuit, without the isolated heart, causes a reduction in blood pressure of the blood donor and a significant increase in norepinephrine from 277 ± 44 to 634 ± 130 pg/ml; p 〈 0.05. Two hours of aerobic perfusion of the isolated heart inserted in the perfusion circuit, decreases arterial pressure of the blood donor with a concomitant increase of plasma norepinephrine from 475 ± 150 to 841 ± 159 pg/ml; p k〈 0.05. Developed pressure, oxygen consumption, glucose and NEFA uptake of the isolated heart remain constant during two hours of aerobic perfusion, NEFA being the preferred substrate. Tissue content of high energy phosphates at the end of the perfusion is high and similar to that observed “in vivo”. Despite this, there is a release of lactate and CPK from the isolated heart. We conclude that: 1) the model allows accurate measurement of hemodynamics and metabolism of both the isolated heart and the blood donor animal; 2) the perfusion procedure modifies the substrates concentration of the blood donor animal which, in turn, results in the preferential NEFA utilization of the isolated heart. These changes do not affect the functional parameters of the perfused heart.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003950050145
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  • 5
    Electronic Resource
    Electronic Resource
    Lipid peroxidation during myocardial reperfusion (1992)
    Springer
    Molecular and cellular biochemistry 111 (1992), S. 49-54 
    Details
    ISSN: 1573-4919
    Keywords: thiobarbituric acid test ; liquid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Reperfusion of heart muscle after prolonged ischaemia is associated with metabolic and functional abnormalities and eventual cell death. Free radical induced lipid peroxidation of cell membranes is thought to be a major mechanism in the evolution of reperfusion damage. The evidences in support for this kind of damage are based on tissue malondialdehyde quantitation by the thiobarbituric acid test (TBA-test). In an attempt to verify this topic we have subjected isolated and Langendorff perfused rabbit hearts to a period of 60 minutes of severe ischaemia plus 30 minutes of reperfusion. At appropriate time points malondialdehyde was determined in the tissue by means of TBA-test and directly by reversed phase, high pressure, liquid chromatography (HPLC). We have found no correlation between the two compared assays. During reperfusion, there was the formation of non-lipid related, malondialdehyde-like, TBA-reactive substance which leads to overstimations of the extent of lipid peroxidation. On the contrary, by direct HPLC quantitation, there was a decrease of tissue malondialdehyde during ischaemia and during the early phases of reperfusion. Our results demonstrate that TBA-test is not a reliable index of malondialdehyde accumulation in organ system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229573
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of prolonged treatment with propionyl-L-carnitine on erucic acid-induced myocardial dysfunction in rats (1992)
    Springer
    Molecular and cellular biochemistry 112 (1992), S. 117-123 
    Details
    ISSN: 1573-4919
    Keywords: propionyl-L-carnitine ; erucic acid ; cardiomyopathy ; heart failure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The aim of this study was to evaluate the ability of propionyl-L-carnitine to prevent cardiac damage induced by erucic acid. Rats were fed for 10 days with normal or 10% erucic acid—enriched diets with or without propionyl-L-carnitine intraperitoneally injected, (1 mM/kg daily, for 10 days). The erucic acid diet produced increases in triglycerides (from 5.6 to 12.4 mg/gww, P 〈 0.01), and free fatty acids (from 2.0 to 5.1 mg/gww, P 〈 0.01), but no changes in phospholipids. When the hearts were perfused aerobically with an isovolumic preparation there was no difference in mechanical activity. On the contrary, when pressure-volume curves were determined, the pressure developed by hearts from the erucic acid-treated rats were reduced. Independent of diet, propionyl-L-carnitine treatment always produced positive inotropy. This was concomitant with improved mitochondrial respiration (RCI 5.1 vs 9.3, P 〈 0.01), higher tissue ATP content (10.3 vs 18.4 μmol/gdw P 〈 0.01) and reduction of triglycerides (12.4 vs 8.0 mg/gww, P 〈 0.01). These data suggest that propionyl-L-carnitine, when given chronically, is able to prevent erucic acid-induced cardiotoxicity, probably by reducing triglyceride accumulation and improving energy metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227568
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of felodipine on the ischemic heart: Insight into the mechanism of cytoprotection (1996)
    Springer
    Cardiovascular drugs and therapy 10 (1996), S. 425-437 
    Details
    ISSN: 1573-7241
    Keywords: calcium antagonist ; felodipine ; myocardial ischemia ; reperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To assess whether the administration of felodipine protects the myocardium in a dose-dependent manner against ischemia and reperfusion, isolated rabbit hearts were infused with three different concentrations of felodipine: 10-10, 10-9, and 10-8 M. Diastolic and developed pressures were monitored; coronary effluent was collected and assayed for CPK activity and for noradrenaline concentration; mitochondria were harvested and assayed for respiratory activity; and ATP production and calcium content and tissue concentration of ATP, creatine phosphate (CP), and calcium were determined. The occurrence of oxidative stress during ischemia and reperfusion was also monitored in terms of tissue content and release of reduced (GSH) and oxidized (GSSG) glutathione. Treatment with felodipine at 10-10 and 10-9 M had no effect on the hearts when perfused under aerobic conditions, whilst the higher dose reduced developed pressure from 57.7 ± 2.6 to 30.0 ± 2.6 mmHg (p 〈 0.01). On reperfusion treated hearts recovered better than the untreated hearts with respect to left ventricular performance, replenishment of ATP and CP stores, and mitochondrial function. Recovery of developed pressure was 100% at 10-8 M, 55% at 10-9 M, and 46% at 10-10 M. The reperfusion-induced tissue and mitochondrial calcium overload, release of CPK and noradrenaline, and oxidative stress were also significantly reduced. The effects of felodipine were dose dependent. Felodipine inhibited the initial rate of ATP-driven calcium uptake but failed to affect the initial rate of mitochondrial calcium transport. It is concluded that felodipine infusion provides dose-dependent protection of the heart against ischemia and reperfusion. Because this protection also occurred at 10-9 M and 10-10 M in the absence of a negative inotropic effect during normoxia and of a coronary dilatory effect during ischaemia, it cannot be attributed to an energy-sparing effect or to improvement in oxygen delivery. From our data we can envisage two other major mechanisms—(1) membrane protection and (2) reduction in oxygen toxicity. The ATP-sparing effect occurring at 10-8 M is likely to be responsible for the further protection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00051107
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of propionyl-L-carnitine on mechanical function of isolated rabbit heart (1991)
    Springer
    Cardiovascular drugs and therapy 5 (1991), S. 17-23 
    Details
    ISSN: 1573-7241
    Keywords: propionyl-L-carnitine ; myocardial contractility ; pharmacokinetic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied the acute and chronic effects of propionyl-L-carnitine (PLC) on mechanical function of isolated rabbit heart. Propionyl-L-carnitine was either directly delivered in the perfusate (10-9 to 10-3 M) or intraperitoneally injected (250 mg/kg) for 10 days to the animals. When added acutely, propionyl-L-carnitine had no effect on inotropism, heart rate, or coronary perfusion pressure. When added chronically, propionyl-L-carnitine induced a positive inotropic effect, with no changes in heart rate or in coronary perfusion pressure, and it ameliorated the pressure-volume relationship. This effect of propionyl-L-carnitine was independent of the calcium concentration of the perfusion medium, but it was correlated with an increase in the myocardial content of propionyl-L-carnitine. The effect was not apparent after 5 days of treatment, although the tissue content of propionyl-L-carnitine remained unchanged. These data suggest that propionyl-L-carnitine, when given chronically, exerts a positive inotropic effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00128239
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  • 9
    Electronic Resource
    Electronic Resource
    Heat shock protein 72 in cardiac and skeletal muscles during hypertension (1995)
    Springer
    Molecular and cellular biochemistry 146 (1995), S. 1-6 
    Details
    ISSN: 1573-4919
    Keywords: heat shock protein ; hypertension ; aging ; myocardium ; skeletal muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract In order to elucidate the relationship between hypertension and hypertrophy in the production of heat shock proteins, we studied the induction of the HSP72 synthesis by the heart and gracilis muscles of normo (WKY) and hypertensive (SHR) rats subjected to hyperthermia (42°C±0.5 for 15 min). Two age groups were investigated in each strain: young (2 months, with developing cardiac hypertrophy) and old (18 months, with fully developed chronic cardiac hypertrophy). The gracilis muscle never developed hypertrophy, independently of hypertension or aging. 72 kDa inducible protein was determined by Western blot analysis using a specific monoclonal antibody. We also used a commercial standard, loaded on each blot, to quantitate densitometrically the signal. The heart of young SHR responds to heat shock more than their normotensive age-matched control (298.8±24.7% vs 88.3 ±8.5%, p〈0.001). This response is not maintained during aging as we did not find any significant difference between normo-and hypertensive old rats after exposure to hyperthermia (43.6±5.3% vs 65.3±10.4%). Unlike the heart, the gracilis muscle shows a basal spontaneous HSP72 synthesis in both the SHR (71.4±10.8%) and WKY (40.6±11.7%) animals. There was a significant increase in HSP72 synthesis in the gracilis muscle of young SHR with respect to their control (186.2±18.7% vs 115.8±9.9%, p〈0.02) which was maintained also during aging (171.9±17.3% vs 95.2±10.5%, p〈0.01). In conclusion, these data show that hypertension results in an increased synthesis of HSP72 both in cardiac and gracilis muscle in response to heat shock. This abnormal response is attenuated by aging in the heart but not in the gracilis muscle. Thus, the abnormality seems to be independent from hypertrophy and linked to genetic determination of the disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00926874
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  • 10
    Electronic Resource
    Electronic Resource
    The effect of propionyl-L-carnitine on the ischemic and reperfused intact myocardium and on their derived mitochondria (1991)
    Springer
    Cardiovascular drugs and therapy 5 (1991), S. 57-65 
    Details
    ISSN: 1573-7241
    Keywords: Propionyl-L-carnitine ; ischemia ; reperfusion ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To assess whether propionyl-L-carnitine protects rabbit heart against the deterioration caused by ischemia and reperfusion, isolated hearts were infused with a medium containing it in different concentrations. During control, normoxic perfusion, and 60 minutes of low-flow ischemia (37°C) followed by 30 minutes of reperfusion, diastolic, and developed pressures were monitored; coronary effluent was collected and assayed for lactate and creatine phosphokinase (CPK); mitochondria were harvested and assayed for oxidative phosphorylation and calcium content; and tissues for concentration of adenosine triphosphate (ATP) and creatine phosphate. Propionyl-L-carnitine reduced the ischemic deterioration of mitochondrial function and the depletion of tissue stores of ATP. On reperfusion, hearts treated with it recovered better than the untreated hearts with respect to left ventricular performance, replenishment of ATP and CP stores, and mitochondrial function. The reperfusion-induced mitochondrial calcium overload and release of CPK were also reduced. The effect of propionyl-L-carnitine was dose dependent. At 10-8 M it failed to modify ischemic and reperfusion damage but protected well at 10-7 M. No further protection was obtained at 10-6 M. Propionyl-L-carnitine thus protects the myocardium against some of the deleterious effects of ischemia and reperfusion. In particular it protects mitochondrial function, perhaps partly by preventing mitochondrial calcium overload. Because this protection occurs in the absence of a negative inotropic effect during normoxia or of a coronary dilatatory effect during ischemia, it cannot be attributed to an energy-sparing effect or to the improvement of oxygen delivery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00128244
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