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  • Miniaturschwein  (3)
  • electrical conductivity  (2)
  • Acute occlusion of femoral-popliteal bypass  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Research in experimental medicine 166 (1975), S. 115-129 
    ISSN: 1433-8580
    Keywords: Adrenal ; minipig ; scanning electron-microscope ; X-ray microanalysis ; epinephrine ; norepinephrine ; dopamine ; serotonin ; Nebenniere ; Miniaturschwein ; Rasterelektronenmikroskop ; Röntgenmikroanalyse ; Adrenalin ; Noradrenalin ; Dopamin ; Serotonin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es werden an der Nebenniere des erwachsenen Miniaturschweins die technischen Möglichkeiten des histochemischen Nachweises verschiedener biogener Amine durch argentaffine oder chromaffine Reaktionen mittels Rasterelektronenmikroskop und Röntgenmikroanalyse dargestellt. Neben der morphologischen Darstellung lassen sich gleichzeitig die zum Niederschlag gekommenen Mengen an Silber bzw. Chrom durch Summenanalysen aus beliebig großen Arealen nachweisen und aus der Intensität der element-spezifischen Röntgenstrahlung semiquantitativ bestimmen. Daneben erlauben die hohen Aminkonzentrationen im Nebennierenmark auch die Erstellung von Linienanalysen und Elementverteilungsbildern für Silber bzw. Chrom und damit eine einfache Lokalisierung der Amine über das Präparat. Im Nebennierenmark sind fünfmal höhere Mengen an Adrenalin als Noradrenalin nachzuweisen. Kleine Mengen an Adrenalin und Noradrenalin finden sich auch in der Rinde, wo sie auf Grund der Linienanalyse besonders im marknahen Bereich lokalisiert sind. Serotonin ist ebenfalls in Mark und Rinde im Verhältnis von 4,6:1 nachweisbar, obwohl es in diesem Organ nicht gebildet wird.
    Notes: Summary Technical possibilities for the histochemical demonstration of some biogenous amines with the scanning electron-microscope and X-ray microanalysis were shown by using argentaffine and chromaffine reactions. Objects were adrenals of adult minipigs. Beside morphologic studies the amounts of silver or chromium can be determined semiquantitatively by the intensity of the specific X-radiate from "sum up-analysis" out of punctual areas. Furthermore the high amine concentrations in the adrenal medulla permit the performance of "line-analysis" and of "element-distribution-pictures" for silver or chromium. At the points chosen for analysis the concentration of epinephrine + norepinephrine is six times as high in the adrenal medulla as in the cortex; for norepinephrine alone it is only three times higher. Line-analysis shows that the concentration of katecholamines in the cortex is very low in the periphery and high near the medulla. The chromaffine reaction for serotonin leads to a distinct chromium peak in the medulla with a distribution quotient of 4.6 : 1 versus the cortex showing that there must be remarkable amounts of serotonin in the adrenal medulla, inspite of the fact that serotonin cannot be synthetized there from its natural precursor.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Research in experimental medicine 178 (1981), S. 201-210 
    ISSN: 1433-8580
    Keywords: Carbon monoxide ; Haemorheology ; Platelet function ; Arterial wall ; Minipig ; Kohlenmonoxid ; Hämorheologie ; Thrombozytenfunktion ; Arterienwand ; Miniaturschwein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Im Rahmen von Untersuchungen über hämorheologische und gefäßwandschädigende Wirkungen niedriger Kohlenmonoxidkonzentrationen, auch in Hinblick auf den Angiopathierisikofaktor inhalierendes Rauchen, wurden Miniaturschweine Kohlenoxid-Luft-Gemischen mit 160, 185 und 420 ppm CO für 4h/Tag an 1 bis 16 Tagen exponiert. Unter Exposition gegen 160 und 185 ppm CO kam es zu einem signifikanten Anstieg der Plättchenaggregationsneigung. Eine Menge von 420ppm CO führte zu einem Anstieg von Hämatokrit, Blut- und Plasmaviskosität und der Plättchenaggregationsneigung. Während lichtmikroskopisch die Arterienwand nach diesen Expositionen unverändert war, erbrachten rasterelektronenmikroskopische Untersuchungen Adhäsionen von formveränderten Thrombozyten auf dem Arterienendothel, vereinzelt bereits nach einmaliger 4stündiger Exposition gegen 160 oder 185ppm CO. Bei 420 ppm CO konnten nach 4mal 4stündiger Exposition gemischte Mikroparietalthromben auf dem Arterienendothel gefunden werden. Nach vorläufigen transmissionselektronenmikroskopischen Untersuchungen konnten diese Thrombozytenadhäsionen und auch Adhäsionen mononukleärer Elemente immer intraendothelialen Schädigungsherden zugeordnet werden. Diese Untersuchungen zeigen, daß bereits niedrige CO-Konzentrationen im akuten Experiment zu hämorheologischen und an der Arterienwand zu morphologischen Veränderungen führen können. Die weitere Entwicklung dieser Veränderungen bei chronischer Einwirkung und damit eine mögliche Bedeutung für die Umwelthygiene über das Zigarettenrauchen hinaus muß durch entsprechend langfristige Experimente geklärt werden.
    Notes: Summary While investigating the initial effects of low carbon monoxide concentrations on haemorheology and the arterial wall, minipigs were exposed to CO-air mixtures with 160, 185, and 420 ppm CO. The daily exposure time was 4 h. Exposure to 160 and 185 ppm CO led to a significant increase of platelet aggregation. Four hundred twenty parts per million CO caused an increase in haematocrit, blood and plasma viscosity, and in platelet aggregation. When examined by light microscopy, there were no changes in the arterial wall, whereas scanning electron-microscopic examinations revealed adhesions of shape-changed platelets on the arterial endothelium, in some cases already after a single 4-h exposure to 160 or 185 ppm CO. After 4 × 4-h exposures to 420 ppm CO there were mixed microthrombi on the arterial endothelium. According to preliminary transmission electron-microscopic studies these adhesions of platelets and also adhesions of mononuclear elements can always be related to foci of degeneration in the endothelial cells. These examinations showed that low concentrations of carbon monoxide can cause both haemorheological and morphological changes in the arterial wall. The further development of these changes under chronic CO exposure and a possible significance for the environmental hygiene beyond cigarette smoking has to be clarified by long-term experiments.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Research in experimental medicine 157 (1972), S. 300-316 
    ISSN: 1433-8580
    Keywords: Miniature Pig ; Housing ; Catheter Implantations ; Physiological Data ; Miniaturschwein ; Haltung ; Katheterimplantationen ; Physiologische Normalwerte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über Erfahrungen berichtet, die in 5 Jahren an Hanford-Miniaturschweinen gesammelt wurden. Den Schwerpunkt der beschriebenen operativen Techniken bilden chronische Katheterimplantationen zur streßfreien Injektion oder Infusion und Materialentnahme (Blut, Magensaft, Urin) am wachen Tier. Unter anderem wird eine Methode zur simultanen Katheterisierung einer Mesenterialvene und der Pfortader beschrieben, die neben den oben erwähnten Möglichkeiten Pfortaderdruck- und Pfortaderflowmessungen erlaubt. Daneben werden physiologische Größen, die an einer größeren Zahl von Hanford-Miniaturschweinen gewonnen wurden, mitgeteilt.
    Notes: Summary Hanford miniature pigs have been used as experimental animals in our laboratory for 5 years. Main object of the operative procedures, developped during this time, was the chronic implantation of catheters for injection and infusion or withdrawal of body fluids (blood, gastric juice, urine) without stress in unaesthetized animals. Thus a method for simultaneous catheterisation of a mesenteric vein and vena portae is described which allows besides the already mentioned possibilities the measuring of portal venous pressure and portal blood flow. Physiological data observed in these animals are reported.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Langenbeck's archives of surgery 372 (1987), S. 655-656 
    ISSN: 1435-2451
    Keywords: Local thrombolytic therapy ; Acute occlusion of peripheral artery ; Acute occlusion of femoral-popliteal bypass ; Lokale Thrombolyse ; Akuter Arterienverschluss ; Akuter Transplantatverschluss
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 7 Jahre Erfahrung mit der lokalen niedrig dosierten thrombolytischen Behandlung von 564 Beinarterienverschlüssen ergaben: Embolische Verschlüsse liessen sich bis zu einer Dauer ihres Bestehens von 6 Wochen in 72,7% beseitigen, ältere noch in 42,3%. Thrombotische Verschlüsse bis zu einem Alter von 6 Monaten konnten in 58% erfolgreich behandelt werden, ältere nur noch in 36,2%. Die kumulative Durchgängigkeit erfolgreich behandelter Verschlüsse beträgt nach 5 Jahren 89,5% für embolische und 58,8% für thrombotische. Die Differentialtherapie der akuten Beindurchblutungsstörungen muss mit den Gefässchirurgen neu überdacht werden.
    Notes: Summary The results of local low-dose thrombolytic treatments of 564 peripheral arterial occlusions were as follows: Embolic occlusions up to 6 weeks could be removed in 72.7%, the longer lasting occlusions in 42.3%. Thrombotic occlusions lasting up to 6 months were successfully treated in 58%, still older ones in 36.2%. The cumulative patency after 5 years was 89.5% in embolic and 58.8% in thrombotic occlusions. Therefore, the differential therapy of acute peripheral ischemia has to be thought over anew together with the vascular surgeons.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 20 (1999), S. 1279-1288 
    ISSN: 1572-9567
    Keywords: compressibility ; electrical conductivity ; emissivity ; specific heat ; thermal conductivity ; thermal expansion coefficient ; tungsten
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Wire explosion experiments were used to obtain thermophysical properties of tungsten. These properties are specific heat, thermal expansion coefficient, compressibility, and electrical and thermal conductivities and their dependences on temperature. There are strong indications that the emissivity in the liquid range should be dependent on temperature. A proposal has been made for determining the emissivity from comparison of experiments with model calculations. The temperature range is extended up to 10,000 K, and first indications for the near-critical-point behavior were obtained. Other properties such as diffusivity, viscosity, and surface tension may possibly also be derived in this range.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 19 (1998), S. 983-991 
    ISSN: 1572-9567
    Keywords: critical point ; electrical conductivity ; evaporation ; exploding wires ; high temperatures ; refractory metals ; thermal expansion ; tungsten
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Experimental results on exploding tungsten wires in air at atmospheric pressure at current densities ≥107 A·cm−2 and a current rise ≥1010 A·s−1 are presented. Besides the current through the probe and the voltage across it, the diameter of the wire material and its surface temperature have been measured. The final aim of this investigation is the determination of the thermophysical properties of a high-melting liquid metal up to its critical point. Here a first step should be made to demonstrate the reliability of the method and to justify the crucial assumptions. To determine the limits for the applicability of a homogeneous approach used so far, a one-dimensional numerical model in Z-pinch geometry has been used which gives the time evolution of the profiles of temperature, density, and pressure across the wire. The model describes well the main features observed in these experiments. A physical explanation for the maximum in the time dependences of the surface temperature is proposed. This behavior is related to special thermodynamic properties of a two-phase (liquid–gas) mixture forming in a peripheral layer around the liquid metal. The temperature limit is determined for which there are no remarkable gradients of temperature and density across the wire. The specific heat, the thermal expansion coefficient, and the electrical as well as thermal conductivity of liquid tungsten can now, in principle, be obtained. The parameters of the critical point of the liquid-vapor phase transition can also be estimated.
    Type of Medium: Electronic Resource
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