Martin Wenzel

Cytostatika-Konzentrationen in Organen und Tumoren: Vergleich nach intravenöser und intratumoraler Injektion

SummaryThe cytostatic drugs Chlorambucil and Bleomycin were labeled with 131I and with 57Co, respectively; Ruthenocenealdehyde-(N-methyl-N-β-chlorethyl)-hydrazone and Ruthencoene-3-phenyl-prop.1-en-3-one were labelled with the γ-emitter 103Ru.In tumor-bearing mice the elimination and organ distribution of these radioactive substances were tested after intravenous (i.v.) and intratumoral (i.t.) injection of the drugs. The organ load showed lower values after i.t. than after i.v. application, while the radioactivity concentrations in the tumor were considerably increased after i.t. injection. The integrals of the concentration-time curves showed 10–80 times higher concentrations in the tumor after i.t. compared to i.v. injection of the drugs.ZusammenfassungDie Cytostatika Chlorambucil und Bleomycin wurden mit 131J bzw. 57Co markiert, Ruthenocenaldehyd-(N-methyl-N β-chloräthyl)-hydrazo und Ruthenocen-3-phenyl-prop-1-en-3-on mit dem γ-Strahler 103Ru. Diese radioaktiven Modell-Substanzen wurden Tumor-tragenden Mäusen intravenös und intratumoral injiziert und anschließend Exkretion und Organ-Verteilung gemessen.Nach intratumoraler (i.t.) Injektion war die Konzentration im Tumor langanhaltend höher und in den übrigen Organen niedriger als nach i.v.-Injektion. Die im Zeitraum 1–24 Std post inj. dem Tumorgebiet zur Verfügung stehenden Dosen (Integration der Konzentrations-Zeit-Kurven) sind bei i.t.-Injektion 10–80 mal höher als nach i.v. Gabe.The cytostatic drugs Chlorambucil and Bleomycin were labeled with 131I and with 57Co, respectively: Ruthenocenealdehyde-(N-methyl-N-beta-chlorethyl)-hydrazone and Ruthenocene-3-phenyl-prop.1-en-3-one were labeled with the gamma emitter 103Ru. In tumor-bearing mice the elimination and organ distribution of these radioactive substances were tested after intravenous (i.v.) and intratumoral (i.t.) injection of the drugs. The organ load showed lower values after i.t. than after i.v. application, while the radioactivity concentrations in the tumor were considerably increased after i.t. injection. The integrals of the concentration-time curves showed 10--80 times higher concentrations in the tumor after i.t. compared to i.v. injection of the drugs.

Ru-labeled ruthenocenoyl-glycine: comparison of clearance with hippuran

Ruthenocenoyl-glycine (ruppuran) is a metallocene analog of iodo-labeled hippuran. After injection of 103Ru-labeled ruppuran and ruthenocenoyl-1,1′-diglycine in rabbits, measurement with external detectors revealed a very rapid accumulation in the kidneys followed by rapid excretion of the 103Ru activity. By measurement of the radioactivity concentration in plasma and urine samples collected 1–60 min after IV injection, the plasma clearance was calculated and compared with the clearance of 125I-labeled hippuran injected simultaneously. The clearance of ruppuran and ruthenocenoyl-diglycine in rabbits was found to be somewhat higher than that of hippuran. Extrapolating to man (1.73 m3), plasma clearance with both ruthenocene derivatives was approximately 500–600 ml/min. Biochemical data as well as the nuclear properties of 97Ru indicate the usefulness of 97Ru-labeled ruthenocenoyl-glycine as a radiopharmaceutical for kidney function studies.

The use of Auger and conversion-electrons for the detection of γ-emitting radionuclides: Chromatographic quality control of radiopharmaceuticals

The extremely weak β-particles produced by the energy-transfer of the γ-rays of radionuclides on orbital electrons (Auger- and/or conversion electrons) can be measured by a windowless proportional counter with external field. This effect can be used to detect γ-emitting radioisotopes on chromatograms with a reasonable efficiency and a better resolution of narrow spots than by detecting their γ-rays and X-rays with a NaI-detector with collimator. Therefore the purity of compounds labelled with γ-emitters (125I, 99mTc, 75Se) on one- or two-dimensional chromatograms can be checked with scanning equipment used for tritium.

Sex-dependent organ distribution of radiopharmaceuticals: effect of hormones on localization of acetyl-103Ru-ruthenocene

This paper demonstrates modification of organ distribution of a radiopharmaceutical, acetyl-103Ru-ruthenocene, by competing drugs. This radiopharmaceutical concentrates in kidneys of male Wistar rats 15-fold higher than in females of the same strain and age. This concentration in the male is age-dependent. Moreover, the retention of that radiopharmaceutical in male rats kidneys is markedly reduced by pre-treatment of the rats with estradiol, and this effect is dose-dependent. Estradiol is competetively inhibiting the retention of acetyl-ruthenocene by the kidneys, the same effect also being obtained by tamoxifen, an anti-estrogen used clinically for regression of mammary carcinoma. Blocking the retention of acetyl-ruthenocene was also obtained by testosterone and cyproterone-acetate, as well as by ovariectomy, but the block after castration was partially compensated with time. Blood clearance of acetyl-ruthenocene is biphasic, with a first t 1/2 of about 12 h, and a second t 1/2 of about 48 h. The retention of the label is sex-specific also in mice, but only the female mice show a high adrenal affinity and significant changes in its organ distribution. These effects may be due to competition of acetyl-ruthenocene for steroid receptors, or due to its activation of enzymes that are responsible for its transformation into a bindable moiety.

Metabolisierung von [103Ru]-Ruthenocen—In vitro untersuchungen und ein möglicher in vivo test für hydroxylasen

Zusammenfassung Die metallorganische Verbindung Ruthenocen wird in der Leber von Mausen und Ratten hydroxyliert. Diese Reaktion benotigt Sauerstoff und NADPH als Coenzym. Mit Mikrosomen aus Mause-Leber ergibt sich ein K M -Wert von 1,3·10 −4 Mol/1. Mit Hilfe von Ruthenocen, da mit dem γ-Strahler 103 Ru markiert worden ist, kann die Aktivitat von Hydroxylasen in vivo erfast werden. Analog zu den Befunden mit Leberschnitten zeigt sich mit dem in vivo Test eine Sexualspezifitat der Ruthenocen-Hydroxylierung (♂ > ♀) und eine verstarkte Hydroxylierung nach Induktion unspezifischer Hydroxylasen durch Bariturat. Die 103 Ru-Konzentration in Lunge und Niere ise—bei oraler-Applikation von [ 103 Ru]-Ruthenocen—nach Barbiturat-Vorbenhandlung drastisch vermindert.

Autoradiographical investigations on the affinity of acetyl-(103Ru)-ruthenocene for the adrenal glands of mice

Whole-body autoradiography was used to investigate the distribution of acetyl-103-ruthenium-(103Ru)-ruthenocene in female mice 2 and 24 h after intravenous application. Two hours after the application of acetyl-(103Ru)-ruthenocene, the nasal mucosa, colon, lung, liver, spleen and especially the adrenal glands were labelled. After 24 h, apart from the absence of labelling of the colon, the labelling pattern did not differ from that obtained 2 h after application. Again, the adrenal glands were particularly strongly labelled. Microautoradiography was performed to investigate the distribution of acetyl-(103Ru)-ruthenocene within the adrenal glands. It was shown that acetyl-(103Ru)-ruthenocene labelling was restricted to the zona reticularis and the inner zona fasciculata of the adrenal cortex. After the stimulation of glucocorticoid synthesis in the adrenal cortex by adrenocorticotropic hormone (ACTH) pretreatment, the labelled area in the zone fasciculata was clearly enlarged. It is concluded that acetyl-(103Ru)-ruthenocene has an affinity for those regions of the adrenal glands where adrogen and glucocorticoid synthesis occur.

Automatic and nondestructive scanning of 14C and 3H on two-dimensional chromatograms

Abstract With a usual chromatogram-scanner, programmable for movement of chromatogram and recorder-paper along the X- and Y-axes, the scanning of two-dimensional chromatograms with 14C- and 3H-labeled substances is demonstrated. The only additional equipment needed is a dot-printer, which is exchanged for the pen-recorder of the scanner. The radioactivity distribution on thin-layer chromatograms containing 0.001 μCi 14C and for 0.008 μCi 3H separated in several spots can be detected in an overnight scan without modifying the chromatogram in any way. Quantitative evaluation of the radioactivity in different spots by counting the number of the corresponding dots showed a good agreement with the relation of actual radioactivity in the spots. Resolution of narrow spots and the sensitivity can be increased by electronic background subtraction. The separation of double-labeled compounds (i.e., 3 H 14 C on the same spot is possible.

[The detection of serum proteins on cellulose acetate with IR. A simplified method for the evaluation of unstained electropherograms on cellulose acetate membranes (author's transl)].

Das Absorptionsmaximum von Proteinen im Infrarot-Licht bei 6//m entspricht dem Absorptionsminimum von Cellulose-Acetat. Es läßt sich daher ungefärbtes Protein auf Cellulose-Acetat-Folie im Bereich von 10—300 g quantitativ bestimmen. Wegen der geringen Streuung im Infrarot im Vergleich zu sichtbaren Licht ist es nicht nötig, die Folie transparent zu machen. Es ist somit prinzipiell möglich, die Auswertung von Serum-Elektropherogrammen auf Cellulose-Acetat-Folie erheblich zu vereinfachen.