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  • 2000-2004  (2)
  • 1890-1899
  • Gas chromatography  (1)
  • Nuclear imaging  (1)
  • 1
    ISSN: 1434-0879
    Keywords: Key words Nitric oxide metabolites ; Erectile dysfunction ; Griess reaction ; Gas chromatography ; Mass spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Recent research implicated that the relaxation of cavernous arterial and trabecular smooth muscle – the crucial event in penile erection – is initiated by the release of nitric oxide (NO) from nerve terminals within the cavernous tissue as well as from the endothelia that line the lacunar spaces and the intima of penile arteries. The present study was undertaken to determine whether plasma levels of the NO metabolites nitrate (NO− 3) and nitrite (NO− 2) in the systemic and cavernous blood of male subjects change during different penile conditions, and whether there is a difference in the NO− 3 and NO− 2 levels of normal males and patients with erectile dysfunction (ED). Twenty-four potent adult male volunteers and 15 patients with ED were exposed to visual and tactile erotic stimuli in order to elicit penile tumescence and, in the group of healthy volunteers, rigidity. Whole blood was aspirated from the corpus cavernosum and the cubital vein, and NO− 3 and NO− 2 levels were determined in plasma aliquots by means of the Griess reaction and a method combining gas chromatography and mass spectrometry (GC-MS). The mean systemic and cavernous plasma NO3 −/NO2 − level in blood samples obtained from the healthy volunteers was 25–31 μM when determined by means of the Griess reaction and 37–41 μM when measured by GC-MS. Both approaches revealed that NO3 −/NO2 − levels in the peripheral and cavernous blood do not change appreciably during developing erection, rigidity and detumescence. Moreover, no significant differences were found between NO3 −/NO2 − plasma levels in the systemic and cavernous blood samples taken from the normal subjects and patients during penile flaccidity, tumescence and detumescence. Our results may reflect the fact that NO metabolism in the corpora cavernosa in the phases of penile tumescence and rigidity may account for only a minor fraction of local levels of NO3 − and NO2 −, which may also derive from exogenous sources. Moreover, the basal levels of NO metabolites in the blood flushing the lacunar spaces of the cavernous body in the state of developing erection could conceal any release of NO that may occur within the penile tissue. Thus, we conclude that the quantification of NO metabolites by means of advanced detection methods, such as GC-MS, is of no use in the workup of ED.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 40 (2000), S. 103-110 
    ISSN: 1432-2102
    Keywords: Schlüsselwörter ; Kardiale Bildgebung ; Angiographie ; Nuklearmedizin ; Magnetresonanztomographie ; Computertomographie ; Key word ; Cardiac imaging ; Angiography ; Nuclear imaging ; Magnetic resonance tomography ; Computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Purpose: Cardiac imaging includes determination of the size and structure of the cardiac chambers, valves, great vessels and the coronary arteries, chamber and valvular function, myocardial perfusion, viability and metabolism. Material and methods: Chest roentgenography, angiography, echocardiography and nuclear imaging are commonly used but computed tomography and magnetic resonance imaging also offer a promising potential. Results: Coronary angiography is the gold standard in assessing coronary anatomy. Fast CT technologies such as electron-beam and multi-row-CT are promising non-invasive imaging modalities in the assessment of coronary artery disease. With intravascular ultrasound early stages of coronary atherosclerosis can be detected. For the assessment of myocardial perfusion and viability as well as cardiac function, scintigraphic methods are widely accepted. However, MRI methods have also reached a high degree of accuracy. Evaluation of chamber and valvular function is, due to its wide availability, the field of echocardiography. Conclusions: In clinical routine chest roentgenography, angiography, echocardiography and nuclear imaging are well established. The value of computed tomography and magnetic resonance imaging in the evaluation of coronary artery disease, myocardial perfusion, viability and metabolism is yet to be defined.
    Notes: Zusammenfassung Zielsetzung: Anforderungen an die kardiale Bildgebung sind die Darstellung der Anatomie der Herzhöhlen, Herzklappen, Koronararterien und der großen Gefäße, Parameter der Ventrikel- und Klappenfunktion, der Myokardperfusion, Myokardvitalität und des myokardialen Stoffwechsels. Material und Methode: In der Bildgebung kommen neben den etablierten Standardverfahren wie Röntgen, Angiographie, Echokardiographie und nuklearmedizinischen Methoden auch neuere Verfahren der Computer- und Magnetresonanztomographie zum Einsatz. Ergebnisse: Die Koronarangiographie ist der Goldstandard in der Darstellung des gesamten Koronarsystems. In der Diagnostik der koronaren Herzerkrankung zeigen schnelle CT-Verfahren wie die Elektronenstrahltomographie (EBT) und die Mehrzeilendetektor-CT (MDCT) Vorteile gegenüber der Kernspintomographie. Frühstadien der koronaren Arteriosklerose können nur mit dem intravaskulären Ultraschall (IVUS) erkannt werden. Nuklearmedizinische Methoden sind in der Untersuchung der Myokardperfusion und -vitalität etabliert. Mit der MRT scheint eine qualitative und quantitative Bestimmung der regionalen Perfusion, Funktion und Vitalität möglich zu sein. Die Untersuchung der linksventrikulären Funktion und der Herzklappen ist die Domäne der Echokardiographie. Schlussfolgerung: In der klinischen Routine sind die Angiographie, Echokardiographie und die Nuklearmedizin etablierte Methoden. Der Stellenwert der Magnetresonanz- und Computertomographie in der Diagnostik der koronaren Herzerkrankung und der Herzfunktion, Perfusion und Vitaltät ist noch nicht definiert.
    Type of Medium: Electronic Resource
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