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  • 1
    ISSN: 0942-0940
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An Albinoratten wurde eine Kälteläsion in der linken Hirnrinde histologisch und mittels131J-RISA-Autoradiographie untersucht. Das Eindringen von14C-Urea und3H-Wasser in Gehirn- und Muskelgewebe wurde zu verschiedenen Zeitpunkten nach der intravenösen Injektion der radioaktiven Isotopen bestimmt; diese wurden in einer Probeserie in Salzlösung, in einer anderen in Urovert gegeben. An der Läsionsseite ergab sich eine vierprozentige Zunahme des Wassergehalts der Hirnrinde und des Marklagers. Die14C-Harnstoff-Aufnahme im ungeschädigten Hirngewebe zeigte einen bemerkbaren Bluthirnschrankeneffekt; an der betroffenen Seite war sie gekennzeichnet von einer Störung der Schranke. Die gestörte Schrankentätigkeit ließ sich histologisch darstellen durch das Austreten von Exsudat in der geschädigten Rinde, und ebenfalls durch die Verbreitung des Exsudats in das unterliegende Marklager, wie die Autoradiographie zeigte. Das Eindringen von3H-Wasser wurde von keiner Schrankenwirkung gehemmt. Die verzögerte Aufnahme des3H-Wassers im geschädigten Hirngewebe gab einen Hinweis für eine verringerte örtliche Durchblutung. Die Wirkung von Urovert zeigte sich vornehmlich in einer Verdünnung der Plasmaradioaktivität; eine Entwässerung der Gewebe konnte nicht nachgewiesen werden.
    Abstract: Résumé Chez des rats albinos une étude histologique et autoradiographique à la serum albumine radioiodée-I131 a été faite sur une lésion corticale gauche provoquée par refroidissement. Le passage de l'urée-C14 et de l'eau-H3 dans le cerveau et le tissu musculaire fut déterminé au diverses intervalles après l'injection intraveineuse des radioisotopes, ceux-ci donnés dans la solution de sel chez l'une série experimentale, et dans l'urovert chez l'autre série. Il résulta une élévation de 4% du taux de l'eau dans le cortex et la substance blanche du côté lésé. Le passage de l'urée-C14 dans le tissu cérébral normal montra un effet démontrable de la barrière hémato-encéphalique; dans le tissu lésé il fut caractérisé par une perturbation de la barrière. Cette perturbation fut mise en évidence chez l'examen histologique par une exsudation dans le cortex refroidi; et aussi bien par la diffusion de l'exsudat dans la substance blanche sous-jacente, comme démontrée par l'autoradiographie. La pénétration de l'eau-H3 ne fut pas empêchée par aucune barrière. Dans le tissu lésé le passage ralenti de l'eau-H3 suggéra l'existence d'un débit sanguin localement baissé. L'effet de l'urovert se révéla principalement par une dilution de la radioactivité plasmique; une déshydratation des tissus n'était pas démontrable.
    Notes: Summary In albino rats a left-sided cortical cold injury was studied histologically and by131I-RISA-autoradiography. The penetration of14C-urea and3H-water into brain and skeletal muscle was determined at various time intervals after intravenous injection of the markers, given in saline in one experimental series, and in urovert in another series. There was a 4% increase of water content in cortex and white matter on the side of the lesion. The14C-urea uptake by the uninjured brain tissue showed a demonstrable blood-brain barrier effect; on the injured side it was characterized by a breakdown of the barrier. The impaired barrier function was also apparent histologically from the leakage of exudate in the cortical lesion, and from the spreading of the exudate into the underlying white matter as shown by RISA-autoradiography. The3H-water penetration was not impeded by any barrier. In the injured tissue a delayed3H-water uptake suggested a decreased local blood flow. The effect of urovert was mainly apparent from a dilution of plasma radioactivity; a dehydration of the tissues was not demonstrated.
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  • 2
    ISSN: 1619-7089
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Practical aspects of the measurement of the specificity of immunoassay are reviewed. Antibody heterogeneity in an antiserum makes a pragmatic rather than a theoretical approach necessary. A new method for the measurement of immunoassay specificity is described. This method is based on the errors caused by the cross-reacting antigens and is directly relevant to the validity of results obtained by immunoassay methods. The effect of selectively blocking the least specific antibodies in antisera raised against steroid haptens is tested. The practical consequences of these considerations are tested using steroid radioimmunoassay and enzyme-immunoassay.
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  • 3
    ISSN: 1619-7089
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The specificity of immunoassays can be improved by using a second antiserum to bind substances that cross-react. Both theory and practice show that the effectiveness of the procedure is dependent of the complex interplay of the concentrations of the two antibodies, the concentrations of the three antigens involved (the labelled tracer, the antigen whose concentration is to be measured and the substance that cross reacts) and the affinities of the antibodies for these antigens. Measured cross-reactions can frequently be reduced to zero in the most important concentration ranges thereby enabling one to perform assays upon unpurified materials which other wise would not be possible. Limitations of the method are discussed.
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  • 4
    ISSN: 1619-7089
    Keywords: Polyamine ; Spermidine ; Malignant melanoma ; Polychemotherapie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Before, during, and after 19 courses of chemotherapy given to patients with disseminated malignant melanoma plasma spermidine levels were determined with a radioimmunoassay. Baseline values were normal in 17 courses, a doubling of plasma levels following chemotherapy occurred in 13 courses. There was no relation between the occurrence of a tumor response and an increase in spermidine levels nor between hematological toxicity or digestive tract toxicity and spermidine levels.
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  • 5
    ISSN: 1619-7089
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract 57Co-bleomycin is useful in the detection and staging of lung cancer, but the long half-life of 57Co (270 days) has discouraged its widespread acceptance. We investigated the shorter living positron emitting 55Co (half-life 18.2 h) as a label for bleomycin. In eleven patients with proven lung cancer scintigraphy with 55Co-bleomycin, using a positron camera, demonstrated the tumor in ten cases. Tumor to lung ratios were calculated. The results were superior to those obtained with 55Co-bleomycin single photon imaging but inferior to those obtained with 57Co-bleomycin scintigraphy.
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  • 6
    ISSN: 1619-7089
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The theory of the measurement of the specificity of antigen binding by antibodies is reviewed. The specificity of steroid immunoassay has been investigated using a new solid phase radioimmunoassay system. The effects of plasma proteins on the specificity of the immunoassays have been tested. The methods used and the conclusions reached have been tested with homogeneous antibodies in order to simplify the interpretation of the results obtained. A new criterium of antibody homogeneity is proposed. The importance of correcting all results accurately for “non-specific binding” is emphasised. A new method for plotting radioimmunoassay standard curves is presented.
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  • 7
    ISSN: 1619-7089
    Keywords: Metabolic imaging ; PET ; NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using positron emission tomography (PET) in combination with compounds labelled with positron-emitting radionuclides like 11C, 13N and 15O, it is possible to study metabolism in vivo in a non-invasive way. Nuclear magnetic resonance (NMR) imaging takes advantage of the spin of protons in water molecules to measure both their number and relaxation times in vivo, but is, in principle, not limited to protons and can also be used for other nuclei with a non-zero spin, e.g. 13C and 31P. The use of 13C opens the possibility of studying the metabolism of a large number of compounds. In order to choose the appropriate methodology for metabolic imaging, i.e. PET or NMR, it is important to know the sensitivity of each modality. The present study outlines the sensitivity of both techniques.
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  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 183 (1959), S. 1395-1396 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In this communication results on the effect of ethylenediamine tetraacetate on the intestinal absorption of radioactive vitamin B12 by gastrectomized rats are presented. We preferred the use of animals in which the entire stomach had been resected because in this way a possible influence of ...
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Pharmacy world & science 3 (1981), S. 1285-1301 
    ISSN: 1573-739X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Good Manufacturing Practice (GMP) is concerned with both manufacturing and quality control procedures. Good radiopharmacy practice means GMP applied to radiopharmaceuticals by taking into account the special nature of these products. Because radioactive substances are the essential basis for the acquisition of data from nuclear medicine investigations, attention has to be paid to the control of all parameters of quality assurance. This is particularly important in those cases where quality control tests have to be performed on apost factum basis,i.e. after administration to the patient, because of the short half-life time of the radionuclide. Radiopharmaceutical quality control is a necessity in all nuclear medicine departments. If a laboratory does not institute radiopharmaceutical quality control until the cause of a ‘poor image’ in the diagnostic process must be identified, the problem will be compounded. The quality control tests must be mastered before they can be used to resolve problems.
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  • 10
    ISSN: 1619-7089
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The level of the aminoterminal propeptide Col 1–3 of type III procollagen (PC-III) was determined in patients with paroxysmal nocturnal haemoglobinuria (PNH) and primary myelofibrosis (PMF), to study whether PC-III can be used as a parameter for the rate and/or degree of bone marrow replacement with collagen. Normal PC-III levels were found in PNH (6.6±1.1 μg/l; N: 8.6±1.8 μg/l), while significantly increased levels were found in PMF (24.8±2.2 μg/l). During a follow-up of 1 year, a slight increase of 2 μg/l occurred in three patients with a stable fibrosis, while one patient with more active disease demonstrated an increase of 25 μg/l. Treatment with acetylsalicylic acid led to a decline of PC-III as well as β-thromboglobulin level, although normalization did not occur. It was demonstrated by means of gel filtration that the antigens related to the PC-III peptide were heterogenous, and that in PMF at least two main peaks were present, with molecular masses equal to and smaller than PC-III peptide. These data demonstrate that the radioimmunoassay cannot be used for the quantitative determination of PC-III; nevertheless it gives some insight in the process of bone marrow fibrosis.
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