Peripheral blood parameters (hematocrit, counts of red blood cells, reticulocytes, white blood cells and platelets, differential blood count) were analyzed after single injections of the cytostatic agents titanocene dichloride; (ED90, 40 mg/kg; LD10, 60 mg/kg) and cisplatin (ED90, 10 mg/kg). Whereas cisplatin depressed the number of reticulocytes and polychromatophilic erythrocytes to near zero level, titanocene dichloride did not obviously affect the supply of young erythrocytes from bone marrow; red blood cell count and hematocrit values were never reduced after application either of titanocene dichloride or of cisplatin. In the case of leukocytes, white blood cells count did not leave the normal range after treatment with titanocene dichloride, whereas a diminution under control values was observed after application of cisplatin. Finally, the number of circulating platelets transiently decreased beneath control range as well after application of titanocene dichloride as of cisplatin. The results indicate an only slight myelotoxicity induced by titanocene dichloride, the platelets being the only cells affected in a reversible manner. Thus, myelosuppression by titanocene dichloride is apparently even less pronounced than in the case of cisplatin.
The pattern of organ toxicity after single injections of the antitumor agent titanocene dichloride in ED90 (40 mg/kg) and LD10 (60 mg/kg) doses to female mice was investigated by analyzing various blood chemical parameters and the composition of urine at intervals between 30 min and 16 days after administration. Whereas the serum levels of electrolytes, blood urea nitrogen, creatinine, total bilirubin and cholesterol did not alter, marked and simultaneous increase in serum concentrations of the enzymes gultamate dehydrogenase, glutamine-oxaloacetic transaminase and glutamic-pyruvic transaminase occurred pointing to cellular damage within liver parenchyma; these lesions were apparently reversible within 8 and 16 days after application of titanocene dichloride even at the LD10 dose. Moreover, glucose concentration decreased immediately after titanocene dichloride administration, obviously stimulating a regulative output of glucagon and cortisol; these effects were also reversible within 4 to 8 days after titanocene dichloride administration. No hints to nephrotoxicity induced by titanocene dichloride became manifest in the present study.
The effect of a single application of toxicologically equivalent doses of the cytostatically active metal complexes titanocene dichloride, upon the morphologic appearance and the functional behavior of the kidneys was analyzed in mice by use of light and electron microscopy, by determination of blood retention values and by urine analysis. The dichlorides of titanium caused only slight morphologic alterations such as increased vacuolation in the proximal tubular cells even after administration of LD50 doses; severe pathologic injuries within the kidneys were always lacking.
In the present study, the subcellular distribution of titanium in the liver of mice was determined 24 and 48 hr after application of a therapeutic (ED100; ED = effective dose) and a toxic (LD25; LD= lethal dose) dose (60 and 80 mg/kg, respectively) of the antitumor agent titanocene dichloride by electron spectroscopic imaging at the ultrastructural level. At 24 hr titanium was mainly accumulated in the cytoplasm of endothelial and Kupffer cells, lining the hepatic sinusoids. Titanium was detected in the nucleoli and the euchromatin of liver cells, packaged as granules together with phosphorus and oxygen. One day later titanium was still present in cytoplasmic inclusions within endothelial and Kupffer cells, whereas in hepatocyte nucleoli only a few deposits of titanium were observed at 48 hr. At this time titanium was mainly accumulated in the form of highly condensed granules in the euchromatin and the perinucleolar heterochromatin. It was found in the cytoplasm of liver cells, incorporated into cytoplasmic inclusion bodies which probably respresent lysosomes. Sometimes these inclusions were situated near bile canaliculi and occasionally extruded their content into the lumen of bile capillaries. This observation suggests a mainly biliary elimination of titanium containing metabolites. These results confirm electron spectroscopic imaging to be an appropriate method for determining the subcellular distribution of light and medium weight elements within biological tissues. Insights into the cellular mode of action of titanocene complexes or titanocene metabolites can be deduced from the findings of the present study.
The passage of titaniun containing metabolites across the placenta into the embryonal compartment was investigated by analyzing the titanium content in embryos/fetuses at various intervals between 1 hr and 24 hr after treatment of pregnant mice with single doses of the antitumor agent titanocene dichloride (60 mg/kg) on days 10, 12, 14 or 16 of gestation. After treatment on days 10, 12 or 14, the titanium concentrations were not elevated in comparison to untreated embryos. Only on day 16, beyond the end of organogenesis, small amounts of titanium were detectable in the fetal compartment 4-24 hr after substance application, exceeding the control values by ranging between 2 and 3. These results explain the absence of histologic lesions in developing embryonal organs and the lack of multiple teratogenic effects in new-borns after application of therapeutic doses of titanocene dichloride to pregnant mice during the embryonal organogenesis.
The pharmacokinetics and organ distribution of titanium were analyzed at various intervals up to 96 hr after a single ip injection of a therapeutic dose of the antitumor agent titanocene dichloride (60 mg/kg). Highest organ concentrations were found in the liver and the intestine where 80-90 mg titanium/kg dry weight were accumulated at 24 and 48 hr, corresponding to liver/blood and intestine/blood ratios of 8-9.
The serum concentrations of cortisol, aldosterone, progesterone and catecholamines were determined 30 min, 1, 2, 4, 8, 24 and 48 hr after application of single doses of titanocene dichloride (60 mg/kg) to non-pregnant and to pregnant mice (treatment on day 10 of gestation). Titanocene dichloride induced 5-6 fold increases in serum cortisol concentration of pregnant as well as of non-pregnant mice within 1-2 hr after substance application. The serum levels of aldosterone, progesterone and catecholamines were not influenced by treatment with titanocene dichloride. It is supposed that the augmentation of cortisol in the serum is due to a rapid release of cortisol from the suprarenal glands after application of titanocene dichloride thus mediating indirectly the induction of cleft palate in mice.
In the present study, the subcellular distribution of titanium in the liver of mice was determined 24 and 48 hr after application of a therapeutic (ED100; ED = effective dose) and a toxic (LD25; LD= lethal dose) dose (60 and 80 mg/kg, respectively) of the antitumor agent titanocene dichloride by electron spectroscopic imaging at the ultrastructural level. At 24 hr titanium was mainly accumulated in the cytoplasm of endothelial and Kupffer cells, lining the hepatic sinusoids. Titanium was detected in the nucleoli and the euchromatin of liver cells, packaged as granules together with phosphorus and oxygen. One day later titanium was still present in cytoplasmic inclusions within endothelial and Kupffer cells, whereas in hepatocyte nucleoli only a few deposits of titanium were observed at 48 hr. At this time titanium was mainly accumulated in the form of highly condensed granules in the euchromatin and the perinucleolar heterochromatin. It was found in the cytoplasm of liver cells, incorporated into cytoplasmic inclusion bodies which probably respresent lysosomes. Sometimes these inclusions were situated near bile canaliculi and occasionally extruded their content into the lumen of bile capillaries. This observation suggests a mainly biliary elimination of titanium containing metabolites. These results confirm electron spectroscopic imaging to be an appropriate method for determining the subcellular distribution of light and medium weight elements within biological tissues. Insights into the cellular mode of action of titanocene complexes or titanocene metabolites can be deduced from the findings of the present study.
