Impact of aliphatic acyl and aromatic thioamide substituents on the anticancer activity of Ru(II)-p-cymene complexes with acylthiourea ligands-in vitro and in vivo studies

Six different acylthiourea ligands (L1-L6) and their corresponding Ru(II)-p-cymene complexes (P1-P6) were designed to explore the structure-activity relationship of the complexes upon aliphatic chain and aromatic conjugation on the C- and N-terminals, respectively. The compounds were synthesized and adequately characterized using various analytical and spectroscopic techniques. The structures of P2-P6, solved using single crystal X-ray diffraction (XRD), confirmed the neutral monodentate coordination of the S atoms of the acylthiourea ligands to Ru(II) ions. In silico studies showed an increase of lipophilicity for the ligands with an increase in alkyl chain length or aromatic conjugation at the C- or N-terminal, respectively. Subsequently, mitogen-activated protein kinases (MAPK) were predicted as one of the primary targets for the complexes, which showed good binding affinity towards extracellular signal-regulated kinases (ERK1, ERK2 and ERK5), c-Jun N-terminal kinase (JNK) and p38 of the MAPK pathway. Henceforth, the complexes were tested for their anticancer activity in lung carcinoma (A549) and cisplatin-resistant lung carcinoma (cisA549R) cells and human umbilical vein epithelial normal cells (HUVEC). Interestingly, an increase in chain length or aromatic conjugation led to an increase in the activity of the complexes, with P5 (7.73 and 13.04 μM) and P6 (6.52 and 14.45 μM) showing the highest activity in A549 and cisA549R cells, which is better than the positive control, cisplatin (8.72 and 44.28 μM). Remarkably, we report the highest activity yet observed for complexes of the type [(η6-p-cymene)RuIICl2(S-acylthiourea)] in the tested cell lines. Aqueous solution studies showed that complexes P5 and P6 are rapidly hydrolyzed to produce solely aquated species that remained stable for 24 h. Staining assays and flow cytometric analyses of P5 and P6 in A549 cells revealed that the complexes induced apoptosis and arrested the cell cycle predominantly in the S phase. In vivo studies demonstrated the higher toxicity of cisplatin and a comparatively higher survival rate of mice injected with the most active complex P6. Histological analyses revealed that treatment with P6 at high doses of up to 8 mg kg-1 did not cause any palpable damage to the tested organs.

Gold nanorod-loaded thermosensitive liposomes facilitate the targeted release of ruthenium(II) polypyridyl complexes with anti-tumor activity

Ruthenium(II) polypyridyl complexes (Ru) show high anti-tumor activity, but their poor solubility and low biocompatibility impede their use in anti-tumor therapy. Here,we circumvented the problem of low solubility by encapsulating the Ru in thermosensitive liposomes (LTSLs) and used gold nanorods (Au NRs) modified on the surface of the liposomes to permit the precise release of Ru at the tumor site. A facile and simple method was developed to synthesize Ru-loaded Au NR-decorated LTSL (Au@LTSL-Ru NPs). The loaded Au NRs improved the anti-tumor effect of Ru and enhanced the photothermal therapeutic properties of the nanosystem. A characterization experiment indicated that the average particle size of Au@LTSL-Ru was approximately 300 nm and that the Au NRs were successfully modified on the surface of LTSL. In thein vitroanti-tumor test, Au@LTSL-Ru and NIR significantly inhibited the proliferation of SGC-7901 cells. The IC₅₀value of Au@LTSL-Ru + NIR was 7.1 ± 1.2μM (13μg ml^-1), and the inhibition rate was greater than 90% when the concentration reached 30μg ml^-1.In vivostudies revealed that Au@LTSL-Ru and NIR had a significant inhibitory effect on subcutaneous tumor tissues derived from SGC-7901 cells. Analysis of histopathology and immunocytotoxicity indicated that Au@LTSL-Ru has fewer side effects and high biocompatibility. Our results confirm that Au@LTSL-Ru can effectively inhibit tumor growth and aid the development of Ru for use in the thermal response in anti-tumor activity research.

Controlled synthesis and size effects of multifunctional mesoporous silica nanosystem for precise cancer therapy

Nanomaterials-based drug delivery systems display potent applications in cancer therapy, owing to the enhanced permeability and retention effect and diversified chemical modification. In this study, we have tailored and synthesized different sized mesoporous silica nanoparticles (MSNs) through reactant control to investigate the relevancy of nanoparticle size toward anticancer efficacy and suppressing cancer multidrug resistance. The different sized MSNs loaded with anticancer ruthenium complex (RuPOP) and conjugated with folate acid (FA) to enhance the selectivity between cancer and normal cells. The nanosystem (Ru@MSNs) can specifically recognize HepG2 hepatocellular carcinoma cells, thus enhance accumulation and selective cellular uptake. The smaller sized (20 nm) Ru@MSNs exhibit higher anticancer activity against HepG2 cells, while the larger sized (80 nm) Ru@MSNs exhibit higher inhibitory effect against DOX-resistant hepatocellular carcinoma cells (R-HepG2). Moreover, Ru@MSNs induced ROS overproduction in cancer cells, leading to DNA damage and p53 phosphorylation, consequently promoting cancer cells apoptosis. Ru@MSNs (80 nm) also inhibited ABCB1 and ABCG2 expression in R-HepG2 cells to prevent drug efflux, thus overcome multidrug resistance. Ru@MSNs also inhibited tumor growth in vivo without obvious toxicity in major organs of tumor-bearing nude mice. Taken together, these results verify the size effects of MSNs nanosystem for precise cancer therapy.

Human topoisomerase inhibition and DNA/BSA binding of Ru(II)-SCAR complexes as potential anticancer candidates for oral application

Three ruthenium(II) phosphine/diimine/picolinate complexes were selected aimed at investigating anticancer activity against several cancer cell lines and the capacity of inhibiting the supercoiled DNA relaxation mediated by human topoisomerase IB (Top 1). The structure-lipophilicity relationship in membrane permeability using the Caco-2 cells have also been evaluated in this study. SCAR 5 was found to present 45 times more cytotoxicity against breast cancer cell when compared to cisplatin. SCAR 4 and 5 were both found to be capable of inhibiting the supercoiled DNA relaxation mediated by Top 1. Interaction studies showed that SCAR 4 and 5 can bind to DNA through electrostatic interactions while SCAR 6 is able to bind covalently to DNA. The complexes SCAR were found to interact differently with bovine serum albumin (BSA) suggesting hydrophobic interactions with albumin. The permeability of all complexes was seen to be dependent on their lipophilicity. SCAR 4 and 5 exhibited high membrane permeability (P _app  > 10 × 10^-6 cm·s^-1) in the presence of BSA. The complexes may pass through Caco-2 monolayer via passive diffusion mechanism and our results suggest that lipophilicity and interaction with BSA may influence the complexes permeation. In conclusion, we demonstrated that complexes have powerful pharmacological activity, with different results for each complex depending on the combination of their ligands.

In vitro evaluation of ruthenium complexes for photodynamic therapy

BACKGROUND

Photodynamic therapy (PDT) is a promising anti-tumor treatment strategy. Photosensitizer is one of the most important components of PDT. In this work, the anticancer activities of PDT mediated by six new ruthenium porphyrin complexes were screened. The mechanisms of the most efficacious candidate were investigated.

METHODS

Photocytotoxicity of the six porphyrins was tested. The most promising complex, Rup-03, was further investigated using Geimsa staining, which indirectly detects reactive oxygen species (ROS) and subcellular localization. Mitochondrial membrane potential (MMP), cell apoptosis, DNA fragmentation, c-Myc gene expression, and telomerase activities were also assayed.

RESULTS

Rup-03 and Rup-04 had the lowest IC₅₀ values. Rup-03 had an IC₅₀ value of 29.5±2.3μM in HepG2 cells and 59.0±6.1μM in RAW264.7 cells, while Rup-04 had an IC₅₀ value of 40.0±3.8μM in SGC-7901 cells. The complexes also induced cellular morphological changes and impaired cellular ability to scavenge ROS, and accumulated preferentially in mitochondria and endoplasmic reticulum. Rup-03 reduced MMP levels, induced apoptosis, and repressed both c-Myc mRNA expression and telomerase activity in HepG2 cells.

CONCLUSIONS

Among six candidates, Rup-03-mediated PDT is most effective against HepG2 and RAW264.7, with a similar efficacy as that of Rup-04-mediated PDT against SGC-7901 cells. Repression of ROS scavenging activities and c-Myc expression, which mediated DNA damage-induced cell apoptosis and repression of telomerase activity, respectively, were found to be involved in the anticancer mechanisms of Rup-03.

Ruthenium-Clotrimazole complex has significant efficacy in the murine model of cutaneous leishmaniasis

In previous studies we reported a novel series of organometallic compounds, Ru^II complexed with clotrimazole, displaying potent trypanosomatid activity with unnoticeable toxicity toward normal mammalian cells. In view of the promising activity of Ru-clotrimazole complexes against Leishmania major (L. major), the present work sought to investigate the anti-leishmanial activity of the AM162 complex in the murine model of cutaneous leishmaniasis. In addition, to facilitate the design of new therapeutic strategies against this disease, we investigated the mode of action of two Ru-clotrimazole complexes in L. major promastigotes. Overall, we demonstrate that AM162 significantly reduced the lesion size in mice exposed to L. major infection. In addition, Ru-clotrimazole compounds are able to induce a mitochondrial dependent apoptotic-like death in the extracellular form of the parasite based on labeling of DNA fragments, mitochondrial depolarization, cell cycle alteration profile and plasma membrane phospholipid externalization. Our findings reveal a promising efficacy of the Ru-clotrimazole AM162 complex for the treatment of cutaneous leishmaniasis, as well as pro-apoptotic activity and thus guarantees further evaluation in pre-clinical studies.

Functionalized Multiwalled Carbon Nanotubes as Carriers of Ruthenium Complexes to Antagonize Cancer Multidrug Resistance and Radioresistance

Multidrug resistance and radioresistance are major obstacles for successful cancer therapy. Due to the unique characteristics of high surface area, improved cellular uptake, and the possibility to be easily bound with therapeutics, carbon nanotubes (CNTs) have attracted increasing attention as potential nanodrug delivery systems. In this study, a CNT-based radiosensitive nanodrug delivery system was rationally designed to antagonize the multidrug resistance in hepatocellular carcinoma. The nanosystem was loaded with a potent anticancer ruthenium polypyridyl complex (RuPOP) via π-π interaction and formation of a hydrogen bond. The functionalized nanosystem (RuPOP@MWCNTs) enhanced the cellular uptake of RuPOP in liver cancer cells, especially drug-resistant R-HepG2 cells, through endocytosis. Consistently, the selective cellular uptake endowed the nanosystem amplified anticancer efficacy against R-HepG2 cells but not in normal cells. Interestingly, RuPOP@MWCNTs significantly enhanced the anticancer efficacy of clinically used X-ray against R-HepG2 cells through induction of apoptosis and G0/G1 cell cycle arrest, with the involvement of ROS overproduction, which activated several downstream signaling pathways, including DNA damage-mediated p53 phosphorylation, activation of p38, and inactivation of AKT and ERK. Moreover, the nanosystem also effectively reduces the toxic side effects of loaded drugs and prolongs the blood circulation in vivo. Taken together, the results demonstrate the rational design of functionalized carbon nanotubes and their application as effective nanomedicine to overcome cancer multidrug resistance.

Biochemical action of new complexes of ruthenium with quinolones as potential antitumor agents

BACKGROUND

The aim of the present study paper was to identify the role of reactive oxygen species (ROS) in apoptosis signaling mechanisms. We used for this purpose two ruthenium complex compounds based on that overproduce these reactive species by their metabolism thus manifesting their antitumor activity too.

MATERIALS AND METHODS

In vivo studies were performed in Walker 256 carcinoma-bearing Wistar rats treated with two ruthenium (III) (Ru(III)) complexes with -fluoroquinolones norfloxacin and ofloxacin. The treatment started 7 days after tumor grafting. We assayed the dynamics of apoptosis by flow-cytometry and the biochemical oxidative status parameters. The biological samples used were serum and whole-tumor tissues; the results were compared to the untreated control group.

RESULTS

The results showed an increase of apoptosis from 14.79% to 59.72% 14.79% to 59.72% in tumor cells treated with the most active combination, ruthenium complex with norfloxacin. We also noted an increase of the oxidative status and ROS production during treatment.

CONCLUSION

The newly-synthesized complexes are less toxic and their activity is based on the induction of oxidative stress.

Nanostructured lipid systems as a strategy to improve the in vitro cytotoxicity of ruthenium(II) compounds

: Tuberculosis is an ancient disease that is still present as a global public health problem. Our group has been investigating new molecules with anti-TB activity. In this context, inorganic chemistry has been a quite promising source of such molecules, with excellent results seen with ruthenium compounds. Nanostructured lipid systems may potentiate the action of drugs by reducing the required dosage and side effects and improving the antimicrobial effects. The aim of this study was to develop a nanostructured lipid system and then characterize and apply these encapsulated compounds (SCARs1, 2 and 4) with the goal of improving their activity by decreasing the Minimum Inhibitory Concentration (MIC₉₀) and reducing the cytotoxicity (IC₅₀). The nanostructured system was composed of 10% phase oil (cholesterol), 10% surfactant (soy oleate, soy phosphatidylcholine and Eumulgin^®) and 80% aqueous phase (phosphate buffer pH = 7.4). Good activity against Mycobacterium tuberculosis was maintained after the incorporation of the compounds into the nanostructured lipid system, while the cytotoxicity decreased dramatically, in some cases up to 20 times less toxic than the unencapsulated drug.

Novel ruthenium - gamma-linolenic acid complex inhibits C6 rat glioma cell proliferation in vitro and in the orthotopic C6 model in vivo after osmotic pump infusion

AIM

Gliomas are primary brain tumours. Gamma-linolenic acid (GLA) exerts anti-proliferative effects. Several ruthenium-containing complexes have antiproliferative effects and can be used as adjuvant therapies in cisplatin-resistant cancer. The present study reports on the anti-proliferative properties and effects on tumour morphology of a novel diruthenium-GLA complex (Ru2GLA) and its comparison with GLA in the C6 rat glioma model both in vitro and in vivo.

MATERIALS AND METHODS

In vitro and in vivo experiments were performed on C6 glioma rat cells, and in an orthotopic model.

RESULTS

Ru2GLA (100 μM) appears to be an inhibitor of C6 rat glioma cell proliferation. The nuclear area of Ru2GLA-treated cells was 2.18-times larger than that of control cells, suggesting DNA replication occurred but mitosis was blocked in the G2-M phase. Ru2GLA (2 mM) inhibited C6 cell proliferation in vivo and the changes in tumor morphology confirm both cellular uptake and collagen fibre-binding in the extracellular matrix.

CONCLUSION

Ru2GLA appears to be a low-toxicity drug and a potential candidate for anti-proliferative therapy of glioma.

Analysis of the cytotoxic effects of ruthenium-ketoconazole and ruthenium-clotrimazole complexes on cancer cells

Ruthenium-based compounds have intriguing anti-cancer properties, and some of these novel compounds are currently in clinical trials. To continue the development of new metal-based drug combinations, we coupled ruthenium (Ru) with the azole compounds ketoconazole (KTZ) and clotrimazole (CTZ), which are well-known antifungal agents that also display anticancer properties. We report the activity of a series of 12 Ru-KTZ and Ru-CTZ compounds against three prostate tumor cell lines with different androgen sensitivity, as well as cervical cancer and lymphoblastic lymphoma cell lines. In addition, human cell lines were used to evaluate the toxicity against non-transformed cells and to establish selectivity indexes. Our results indicate that the combination of ruthenium and KTZ/CTZ in a single molecule results in complexes that are more cytotoxic than the individual components alone, displaying in some cases low micromolar CC50 values and high selectivity indexes. Additionally, all compounds are more cytotoxic against prostate cell lines with lower cytotoxicity against non-transformed epidermal cell lines. Some of the compounds were found to primarily induce cell death via apoptosis yet weakly interact with DNA. Our studies also demonstrate that the cytotoxicity induced by our Ru-based compounds is not directly related to their ability to interact with DNA.

Photodynamic inactivation of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus with Ru(II)-based type I/type II photosensitizers

BACKGROUND

The introduction of new disinfection and sterilization methods, such as antimicrobial photodynamic therapy, is urgently needed for the healthcare industry, in particular to address the pervasive problem of antibiotic resistance. This study evaluated the efficacy and the mechanisms of photodynamic antimicrobial chemotherapy (PACT), also known as photodynamic inactivation (PDI) of microorganisms, induced by novel Ru(II)-based photosensitizers against Staphylococcus aureus and methicillin-resistant S. aureus strains.

METHODS

The photodynamic antibacterial effects of a new class of Ru(II)-based photosensitizers (TLD1411 and TLD1433) were evaluated against a strain of S. aureus (ATCC 25923) and a methicillin-resistant strain of S. aureus (MRSA, ATCC 33592). Bacterial samples were dosed with a range of photosensitizer concentrations (0.3-12 μM) and exposed to 530 nm light (90J cm(-2)) in normoxic conditions (ambient atmosphere) and in hypoxic conditions (0.5% O2).

RESULTS

Both photosensitizers exerted photodynamic inactivation (PDI) of the microorganisms in normoxia, and this activity was observed in the nanomolar regime. TLD1411 and TLD1433 maintained this PDI potency under hypoxic conditions, with TLD1433 becoming even more active in the low-oxygen environment.

CONCLUSION

The observation of activity in hypoxia suggests that there exists an oxygen-independent, Type I photoprocess for this new class of compounds in addition to the typical Type II pathway mediated by singlet oxygen. The intrinsic positive charge of the Ru(II) metal combined with the oxygen independent activity demonstrated by this class of photosensitizers presents a new strategy for eradicating both gram-positive and gram-negative bacteria regardless of oxygenation level.

[Retinal angiomatosis. Ocular manifestation of von Hippel-Lindau disease]

Von Hippel-Lindau disease (VHL disease) is a rare multisystem disorder of autosomal dominant inheritance with high penetrance. Inactivation of the VHL-protein leads to an increased expression of hypoxia induced growth factors. Predilection sites for tumor growth are the retina, the central nervous system and various visceral organs. Retinal capillary hemangioblastoma is one of the earliest manifestations of VHL disease. The lifetime risk of permanent visual loss defined as a visual acuity of 0.5 or less is about 35% in gene carriers. It increases to 60% if there is already retinal capillary hemangioblastoma. If VHL disease is suspected, a careful ophthalmological examination should be included in the clinical screening program. Having confirmed the diagnosis, regular ophthalmoscopic monitoring is essential in order to detect developing tumors at an early stage. Therapeutic options for small to medium sized peripheral tumors are laser or cryocoagulation; larger- hemangioblastomas can be treated by brachytherapy using ruthenium plaques, while asymptomatic juxtapapillary tumors can be observed at regular intervals.

Pharmaceutical development of a parenteral lyophilized formulation of the antimetastatic ruthenium complex NAMI-A

This paper describes the development of a stable pharmaceutical dosage form for NAMI-A, a novel antimetastatic ruthenium complex, for Phase I testing. NAMI-A drug substance was characterized using several spectrometric and chromatographic techniques. In preformulation studies, it was found that NAMI-A in aqueous solution was not stable enough to allow sterilization by moist heat. The effect of several excipients on the stability of the formulation solution was investigated. None of them provided sufficient stability to allow long-term storage of an aqueous solution of NAMI-A. Therefore, a lyophilized product was developed. Five different formulations were prepared and subjected to thermogravimetric (TG) analysis and stability studies at various conditions for 1 year. Minimal degradation during the production process is achieved with a formulation solution of pH 3-4. Of the acids tested, only hydrochloric acid (HCl 0.1 mM) both stabilized the formulation solution and was compatible with the lyophilized product. This product was stable for at least 1 year when stored at -20 degrees C, 25 degrees C/60% relative humidity (RH) and 40 degrees C/75% RH, and was also photostable.

[Results of combined radiotherapy of choroid melanomas]

Method of combined radiotherapy of choroid melanomas, proposed by the authors, includes transscleral irradiation of the tumor by rutenium ophthalmoapplicators and simultaneous intracorporeal irradiation with 59Fe. Twenty-seven patients were treated. Morphological examination of enucleated eyes showed the capacity of 57Fe to incorporate in tumor cell, and observations indicate that this method of treatment not only extends the indications for organ-sparing radiotherapy of uveal melanomas, but delays the development of distant metastases as well.

Kinetics of systemic ruthenium in human blood using a stable tracer

The biokinetics of ruthenium after oral and intravenous administration has been investigated in two human subjects using the stable isotope 101Ru as a tracer. Tracer concentrations in blood plasma have been determined using activation analysis with protons. The results presented here prove that the stable tracer technique is a valuable tool for obtaining relevant information about the biokinetics of ruthenium in humans. From these pilot studies, it may be argued that the clearance of systemic ruthenium from plasma is significantly slower than the predictions of the biokinetic model currently recommended by the International Commission on Radiological Protection (ICRP). The experimental data for the orally administered tracer, which reflect the gastrointestinal absorption process, differ from the curve derived from the ICRP model, suggesting that the uptake into the systemic circulation may be lower than predicted. On the basis of these preliminary data, investigations on a larger number of subjects with improvements in the experimental design are scheduled.

Retention and dosimetry of 106Ru inhaled along with inert particles by Fischer-344 rats

This study was done to provide data useful for predicting the deposition, retention and radiation dose patterns for humans who might be exposed to an aerosol containing 106RuO4 and respirable particles. Ruthenium-106 tetroxide was introduced into air containing inert particles. The inert particles were monodisperse. 0.69 micrometer diameter fused aluminosilicate and very small residue particles from nebulized droplets. A complex exposure atmosphere resulted. In addition to condensation of 106RuO4 on pre-existing particles, self-nucleation occurred, presumably resulting from the formation of RuO2. It appears there was a significant amount of 106RuO4 present in the inhalation exposure system. When a group of Fischer-344 rats inhaled this exposure atmosphere, approx. 12% of the initial body burden reached the pulmonary region of the respiratory tract. Of the remaining 88% of the initial burden, 60% was deposited in the upper respiratory tract, 10% in the tracheobronchial region and 18% was external contamination, primarily on the nares and head skin. Most of the initial body burden was cleared via the gastrointestinal system and excreted via feces. Clearance of 106Ru from the pulmonary region had an effective half-time of approx. 30 days and was predominantly by dissolution. Relative radiation doses accumulated to 100 days after inhalation exposure, normalized to a lung dose of 1.0, were nasopharyngeal mucosa, 11; trachea and larynx, 5; lower large intestine, 5; upper large intestine, 2; liver, 0.9; and kidneys, 0.9. Other tissues and organs received lesser relative doses. Comparable results are predicted for man inhaling a similar exposure atmosphere, which could be encountered under certain circumstances in nuclear industry operations.

Microspheres in cardiac lymph: control and ischemic states

The cardiac lymph from conscious animals was monitored for the presence or absence of radiolabelled 15 micrometer microspheres during: 1) control periods after left atrial injection of microspheres and b) after circumflex coronary artery (CFX) occlusions (10--20 min total or less than 40 mins 50% of control flow) followed by full reperfusions. Microspheres (15 mu) numbering 7--150 were present in the lymph within 2 hrs after the occlusions; and in three experiments, the presence of a small number in the lymph on the following day implied continual release overnight. No microspheres were present in 8--48 hr lymph samples prior to occlusions. This study suggests that some microspheres escape from the intravascular space of the myocardium and are channeled into the cardiac lymphatics; this is apparent even after short-term ischemic events.

[Radiotherapy of intraocular tumours, particularly of melanoma of the choroid (author's transl)]

From 1964 to 1976 a number of 131 patients, suffering from melanoma of the choroid have been treated with 106Ru/106Rh beta-ray applicators. In 81 cases (61.8%) this treatment has been successful. 26 eyes (19.9%) had to be enucleated in spite of the irradiation. 24 patients (18.3%) died, 13 of them of metastases. Only in 46 patients, out of 81, we have reached total destruction of the tumor with flat chorioatrophic scar. In 27 cases visual acuity of 1.5 to 0.5 could be preserved. Radiogenic late complications in the capillary system with disturbances of the retinal blood circulation were the cause of visual deterioration. The 107 surviving patients were controlled during a period of 6.5 years in the average. Survival rate 91.2% after 5 and 84% after 10 years. Another group of 214 patients with melanoma of the choroid, who had been treated from 1955 to 1970 by enucleation reached a survival rate of 72% after 5 years. Treatment with 106Rh beta-irradiation therefore leads to no increased danger of metastases. The following indications for this treatment are suggested: 1. Prominence of the tumor not exceeding 5 mm, largest diameter at its base not more than 15 mm. 2. Distance of the dorsal edge of the tumor at least 1-2 optic disc diameters from the nerve head. 3. Peripheral delimitation against the ciliary body. 4. No tumor growth outside the eye.

[Complications of the irradiation therapy with beta applicators in malign melanomas (author's transl)]

Depending on prominence and localization of malign melanomas of the choroid, there are - besides enucleation - other clinical treatments possible. Irradiation therapy with beta applicators (106Ru/106Rh) gives also radiogenous complications. But contrarily to a treatment with cobalt-60 applicators, these complications are less important.

Convulsions or flaccid paralysis induced by ruthenium red depending on route of administration

Ruthenium red was administered to mice and cats intracranially or intraperitoneally. In mice, intracisternal administration produced status epilepticus and tonic convulsions. In contrast, intraperitoneal administration induced total flaccid paralysis lasting several hours. These effects of Ruthenium red were partially blocked by the simultaneous administration of CaCl2. EDTA, at doses much greater than those of Ruthenium red, produced effects similar to those of the dye, which were also blocked by CaCl2 administration. In cats, intraventricular or intrahippocampal administration of Ruthenium red through a permanently implanted cannula produced after a few minutes subclinical paroxysmal activity in all brain regions recorded. After several hours the animals developed typical grand mal seizures. Intraperitoneal injection of Ruthenium red to cats did not affect the EEG but markedly depressed muscular activity. Administration of carbachol to the latter animals produced myoclonic responses. These results are discussed in relation to the inhibitory effect of Ruthenium red on Ca2+ transport and binding to membranes, and to the role of this cation on neurotransmitter release.