Abstract: The present invention relates to methods for detecting the multidrug resistance phenotype in vivo and in vitro. The invention particularly relates to methods of diagnosing the multidrug resistance phenotype by imaging, particularly scintigraphic imaging, in solid tumors in vivo or in tumors and biopsies in vitro. The methods of the present invention allow the diagnosis of multidrug-resistant tumor and other multidrug-resistant phenotypes without invasive surgical methods.

Abstract: The present invention relates to methods for detecting the multidrug resistance phenotype in vivo and in vitro. The invention particularly relates to methods of diagnosing the multidrug resistance phenotype by imaging, particularly scintigraphic imaging, in solid tumors in vivo or in tumors and biopsies in vitro. The methods of the present invention allow the diagnosis of multidrug-resistant tumor and other multidrug-resistant phenotypes without invasive surgical methods. The present invention is also directed to methods of treating multidrug resistant tumors with novel agents that bind to P-glycoprotein. The novel compounds of the present invention are co-administered with a chemotherapeutic agent in order to enhance accumulation of the drug.

Abstract: The invention relates to compositions that comprise (1) lipophilic cationic organometallic complexes, particularly hexakis(2-methoxyisobutylisonitrile)technetium(I) complex, and (2) an agent that decreases the intramembrane potential of a living cell. Agents which decrease the intramembrane potential of a living cell include the lipophilic anions, especially tetraphenylborate anion. The invention also relates to methods in which the compositions are administered in vivo and in vitro when it is desirable to obtain enhanced cellular accumulation of lipophilic cationic organometallic complexes. The compositions and methods are useful for diagnosis and treatment, pSTATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENTPart of the work performed during development of this invention utilized U.S. Government funds. The U.S. Government has certain rights in this invention.

Abstract: The invention relates to compositions that comprise (1) lipophilic cationic organometallic complexes, particularly hexakis(2-methoxyisobutylisonitrile)technetium(I) complex, and (2) an agent that decreases the intramembrane potential of a living cell. Agents which decrease the intramembrane potential of a living cell include the lipophilic anions, especially tetraphenylborate anion. The invention also relates to methods in which the compositions are administered in vivo and in vitro when it is desirable to obtain enhanced cellular accumulation of lipophilic cationic organometallic complexes. The compositions and methods are useful for diagnosis and treatment, particularly in vivo tissue imaging.