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At least 127 records · Page 7Linked to original sources
PubMed1981

Cytokinetic behavior of Ehrlich ascites tumor after in vivo treatment with cis-diamminedichloroplatinum(II) and metallocene dichlorides.

The influence of an in vivo treatment with optimally tumor-inhibiting doses of cis-diamminedichloroplatinum(II) (DDP), titanocene dichloride (TDC), and vanadocene dichloride (VDC) on the DNA distribution pattern, determined by pulse-cytophotometry, and on the mitotic activity of EAT cells is investigated. Whereas DDP causes an immediate and long-lasting decrease of mitoses but no disturbances of the EAT cell kinetics, a marked G2 block with a maximum at 10-12 h a. t. and an irreversible and extensive mitotic depression is evoked by TDC. In the case of DDP and TDC, the tumor cells are removed several days a. t. by cells belonging to the defensive system of the host animals. In contrast, VDC induces partially synchronized waves after a transient suppression of mitoses and reversible cell accumulation in the late S and in the G2 phases. Additionally, 5-16% of the cells become polyploid after VDC treatment.

Animals↗
PubMed1980

Tumor inhibition by metallocenes: antitumor activity of titanocene dihalides (C5H5)2TiX2 (X=F, Cl, Br, I, NCS) and their application in buffered solutions as a method for suppressing drug-induced side effects.

The antitumor activity of titanocene dihalides (C5H5)2TiX2 with X=F, Cl, Br, I, NCS is investigated against Ehrlich ascites tumor in CF 1 mice. Varying doses of the compounds are applied as single i.p. injections 24 h p.t.t. both in non-buffered (pH 1.4-3.9) and buffered (pH 4.2-5.9) solutions or suspensions, all of the substances achieving in optimum doses cure rates of 100% on day 120 p.t.t. This corresponds to I.L.S. values of 600-750% referred to the untreated controls. Some drug-induced side effects, especially the appearance of postperitonitic symptoms several weeks after i.p. application of higher doses of titanocene dihalides, are strikingly reduced by pH elevation in the injected drug solutions.

Animals↗
PubMed1977

[Biochemistry of metallocenes. III. Thymus-affinity for (103Ru)-ruthenocenyl-3-phenyl-propen-1-one].

103Ru labelled 1-Ruthenocenyl-3-phenyl-propen-1-one was administered to mice introperitoneally. The organ distribution was determined in liver, spleen, lung, muscle, blood, kidney and thymus. The highest concentration was found in the thymus-up to 22% of the injected dose/g with corresponding thymus to muscle ratios of up to 364:1. The consequences for nuclear medicine are discussed.

Animals↗
PubMed1984

Cytologic observations on the effects of metallocene dichlorides on human fibroblasts cultivated in vitro.

The effects of the organometallic cytostatic agents titanocene dichloride (TDC) and vanadocene dichloride (VDC) and of the inorganic cytostatic drug cis-diamminedichloroplatinum(II) (DDP) on the morphologic appearance of human embryonal fibroblasts cultivated as monolayers in vitro were analyzed by light and electron microscopy. All three substances induced similar structural changes which consisted of nuclear as well as cytoplasmic alterations. Many fibroblasts enlarged but the nuclear volume increased more extensively than that of the cytoplasm. The nuclear envelopes underwent invagination so that segmented nuclei were formed and the nucleoli increased in size and density. Within the cytoplasm there was evidence of conspicuous protein synthesis, characterized morphologically by an increase in the size and number of mitochondria, Golgi apparatuses and of cisternae of the rER. The phenomena observed are interpreted as indicating unbalanced cell growth characterized by a selective inhibition of DNA synthesis, coupled with progressive RNA and protein syntheses.

Cell Nucleus↗
PubMed1983

Tumor inhibition by metallocenes: ultrastructural localization of titanium and vanadium in treated tumor cells by electron energy loss spectroscopy.

The intracellular distribution patterns of the metal atoms titanium and vanadium after in vivo as well as in vitro treatment of Ehrlich ascites tumor with the antitumor agents titanocene dichloride (TDC) or vanadocene dichloride (VDC) have been investigated by use of electron energy loss spectroscopy (EELS). The metals were found mainly accumulated in the nuclear heterochromatin and, to a minor extent, in the nucleolus and in the cytoplasmic ribosomes. In connection with other experimental results it is argued that this accumulation is indicative of the molecular interaction of the metal-containing species with the nucleic acids, especially with the DNA.

Animals↗
PubMed1986

Organ toxicity of metallocene dichlorides. The effect of (C5H5)2TiCl2 and (C5H5)2VCl2 on renal structure.

The effect of a single application of toxicologically equivalent doses of the cytostatically active metal complexes titanocene dichloride (TDC), vanadocene dichloride (VDC) or cis-diamminedichloroplatinum(II) (DDP) 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. Whereas DDP induced severe structural lesions of the epithelial cells of the proximal and distal tubules as well as profound functional disturbances of the kidneys, the dichlorides of titanium and vanadium 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 correspondence to these morphologic findings, no impairment of renal function was detectable after treatment with TDC either in effective or in toxic doses.

Animals↗
PubMed2005

[Metallocenes and malaria: a new therapeutic approach].

Rapid development of significant resistance to antimalarial drugs has been a major force driving research to identify and develop new compounds. The use of synthetic organometallic complexes seems to be promising for treatment of malaria infections. Recent progress in identification and development of new drugs promises to lead to a much greater range of antimalarial agents. Organometallic complexes and metalloporphyrins have shown in vitro activity against Plasmodium falciparum. Ferroquine (ferrocenyl chloroquine) is more active than chloroquine against strains and isolates of P. falciparum and shows efficacy against murine parasites.

Animals↗
PubMed2002

Reference potential calibration and voltammetry at macrodisk electrodes of metallocene derivatives in the ionic liquid [bmim][PF6].

Reference potential scales are not generally available in ionic liquids. Consequently, comparison of data with those obtained in conventional solvent (electrolyte) media is not possible. The process [Co(Cp)2](+/0) (Co(Cp)2 = cobaltocene) has been studied at gold, glassy carbon and platinum macrodisk electrodes to test the feasibility of using this redox couple as a voltammetric reference standard in the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]). A reversible, one-electron reduction process was observed, and the measured reversible potential versus a silver quasi-reference electrode was independent of the working electrode material, the concentration, and the scan rate. Ferrocene, the other traditionally used reference compound, is poorly soluble in this ionic liquid. However, the solution-phase voltammetry of ethylferrocene could be readily studied in [bmim][PF6], and a reversible oxidation process was observed. A reversible potential of +1285 +/- 5 mV versus the [Co(Cp)2](+/0) reference potential scale was obtained, and this value is comparable with that obtained in CH3CN (0.1 M Bu4NPF6) when referenced to the same potential scale. Ferrocene, decamethylferrocence, 1,1'-dimethylferrocene, 1,1'-diacetylferrocene, and ferrocenecarboxaldehyde were adhered to the working electrode surface and immersed in [bmim][PF6]. In each case, solid-state voltammetry provided well-defined, reversible one-electron oxidation processes that had the appearance of being diffusion controlled, with charge neutralization occurring via the ionic liquid. Reversible potentials of the solid-state processes referenced against the [Co(Cp)2](+/0) scale were similar to solution-phase values obtained in CH3CN (0.1 M Bu4NPF6).

Journal Article↗
PubMed2002

Effect of asymmetry on the electronic delocalization in diiron and iron-cobalt mixed valence metallocenic compounds.

In this work, we report the synthesis and a study on the degree of electronic delocalization in the asymmetric mixed valence complexes [CpFe(C(8)H(6))Fe(C(8)H(7))](+), 3a(+), and [CpCo(C(8)H(6))Fe(C(8)H(7))](+), 3b(+), (Cp = C(5)Me(5), C(8)H(6) = pentalenyde, C(8)H(7) = hydropentalenyde, and = ((3,5(CF(3))(2)C(6)H(3))(4)B(-))). Electrochemical methods, (57)Fe Mössbauer spectroscopy, electronic spectroscopy, and electron paramagnetic resonance were used for this purpose. Although the anti conformation of the complexes precludes any metal-metal interaction, all the techniques employed show that 3a(+) is a electronic delocalized system, while 3b(+) behaves as two individual metallic centers with localized electron density.

Journal Article↗
PubMed2003

Syntheses and structures of metallocene methyltrihydroborate derivativies: Cp2ZrCl[(mu-H)2BHCH3], Cp2Zr[(mu-H)2BHCH3]2, and Cp2Ti[(mu-H)2BHCH3].

In reactions of zirconocene dichloride, Cp(2)ZrCl(2), with 1 equiv and an excess amount of LiBH(3)CH(3), the methyltrihydroborate complexes, Cp(2)ZrCl[(mu-H)(2)BHCH(3)], 1, and Cp(2)Zr[(mu-H)(2)BHCH(3)](2), 2, were isolated. The reaction of titanocene dichloride, Cp(2)TiCl(2), with an excess amount of LiBH(3)CH(3) produced the monosubstituted methyltrihydroborate complex, Cp(2)Ti[(mu-H)(2)BHCH(3)], 3. The titanium was reduced from Ti(IV) to Ti(III), producing a 17-electron, paramagnetic titanocene complex. Under a dynamic vacuum at room temperature, compound 2 decomposed and produced the zirconium hydride compound Cp(2)ZrH[(mu-H)(2)BHCH(3)]. Single crystal X-ray structures of 1, 2, and 3 were determined. Crystal data for 1: space group P2(1)/c, a = 13.7921(3) A, b = 13.4227(3) A, c = 13.0868(3) A, beta = 91.6448(12) degrees, Z = 8. Crystal data for 2: space group Pna2(1), a = 15.2949(4) A, b = 9.3417(2) A, c = 9.3211(2) A, Z = 4. Crystal data for 3: space group Fmm2, a = 9.1795(3) A, b = 13.0993(5) A, c = 8.8520(3) A, Z = 4.

Journal Article↗