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  • 1
    Electronic Resource
    Electronic Resource
    Wideband harmonic imaging: A novel contrast ultrasound imaging technique (1999)
    Springer
    European radiology 9 (1999), S. S364 
    Details
    ISSN: 1432-1084
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. A novel ultrasonic imaging method, wideband harmonic imaging, for nonlinear imaging of microbubble contrast agents is evaluated. In wideband harmonic mode, two pulses of alternate phase are send out. The image is then processed from the sum of both pulses, resulting in an image of nonlinear scatterers such as microbubbles. A prototype ultrasound system, Siemens Elegra, was evaluated with in vitro investigations and animal trials, using conventional, harmonic and wideband harmonic settings with the galactose based ultrasound contrast agent Levovist. Wideband harmonic imaging offers superior sensitivity for ultrasound contrast agents compared to conventional imaging and harmonic imaging. At low transmit power settings (MI 0.1–0.5) the nonlinear response is already sufficient to generate a image of the blood pool distribution of Levovist in the rabbit kidney including the microvasculature, with clear delineation of vessels and perfused parenchyma. At high transmit amplitudes, nonlinear tissue response reduced the apparent image contrast between contrast agent and tissue. The results suggest that wideband harmonic imaging is currently the most sensitive contrast imaging technique, maintaining highest spatial resolution. This may add to image quality and offer new clinical potential for the use of ultrasound contrast agents such as Levovist.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00014075
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Investigations of droloxifene and other hormone manipulations onN-nitrosomethylurea-induced rat mammary tumours (1992)
    Springer
    Journal of cancer research and clinical oncology 119 (1992), S. 91-96 
    Details
    ISSN: 1432-1335
    Keywords: NMU-induced rat mammary tumours ; Hormonal manipulation ; Droloxifene ; Tumour growth behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of droloxifene, a new anti-oestrogenic drug, onN-nitrosomethylurea-induced mammary tumours of Sprague-Dawley rats was investigated and compared with that of tamoxifen. The response of tumour growth to ovariectomy or to treatment with aminoglutethimide or high doses of oestradiol was also studied. Ovariectomy was by far the most effective treatment for mammary-tumour-bearing animals. More than 75% of the tumours in ovariectomized rats did not grow progressively but remained in remission for up to 12 weeks after castration when the experiment was terminated. The inhibitory effects of droloxifene and tamoxifen on mammary tumour growth were similar, but body weight loss of animals treated with tamoxifen was more marked than that of animals treated with droloxifene at the same dose and schedule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01209662
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Investigations of droloxifene and other hormonal manipulations onN-nitrosomethylurea-induced rat mammary tumours (1992)
    Springer
    Journal of cancer research and clinical oncology 119 (1992), S. 97-100 
    Details
    ISSN: 1432-1335
    Keywords: Droloxifene ; Endocrine-acting drugs ; NMU-induced rat mammary carcinoma ; oestradiol receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary InN-nitrosomethylurea-induced rat mammary tumours, tamoxifen is found to compete at the binding sites of the oestradiol receptor if a receptor determination is performed 1 day following the last drug application to animals. Despite a higher binding affinity of droloxifene (3-OH-tamoxifen) to oestradiol receptor, compared to tamoxifen, its influence on the measurable receptor quantity is only very weak or not demonstrable. Therefore, binding affinity is not a valid explanation for the different influences of the two anti-oestrogens on the receptor. These only can be attributed to different behaviour patterns of both substances in relation to their half-lives and metabolism and accumulation in the organism. Owing to the short half-life of droloxifene, even 1 day after the last application too little drug is available to compete for oestradiol binding sites. In the case of both anti-oestrogenic substances, cessation of drug application for 8 weeks abolished any influence on the oestradiol receptor. Furthermore, failure of aminoglutethimide to influence the oestradiol receptor could be observed because this substance does not act via this receptor. The experiments performed confirm literature data regarding the effect of aminoglutethimide therapy on oestradiol receptors breast tumour tissue of human beings. In summary: receptor investigations ofN-nitrosomethylurea-induced rat mammary tumours, used as a model to test therapy regimens with droloxifene or other drugs with a short half-life, may be of limited value only.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01209663
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    Paper (German National Licenses)
    Fulltext
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