Cytotoxic, clastogenic and genotoxic effects of cis-tetraammine(oxalato)ruthenium(III) dithionate on human peripheral blood lymphocytes

There is a concern about stablishing the clinical risk of drugs used for cancer treatment. In this study, the cytotoxic, clastogenic and genotoxic properties of cis-tetraammine(oxalato)ruthenium(III) dithionite - cis-[Ru(C2O4)(NH3)4]2(S2O6), were evaluated in vitro in human lymphocytes. The mitotic index (MI), chromosomal aberrations (CA) and DNA damage by comet assay were also analyzed. The MTT test revealed that the ruthenium compound showed a slight cytotoxic effect at the highest concentration tested. The IC50 value for the compound after 24 hours of exposure was 185.4 µM. The MI values of human peripheral blood lymphocytes treated with 0.015, 0.15, 1.5 and 150 µM of cis-[Ru(C2O4)(NH3)4]2(S2O6) were 6.1, 3.9, 3.2 and 0.2%, respectively. The lowest concentration, 0.015 µM, did not show any cytotoxic activity. The CA values for the 0.015, 0.15 and 1.5 µM concentrations presented low frequency (1.5, 1.6 and 2.3%, respectively), and did not express clastogenic activity when compared to the negative control, although it was observed clastogenic activity in the highest concentration tested (150 µM). The results obtained by the comet assay suggest that this compound does not present genotoxic activity at lower concentrations. The results show that cis-[Ru(C2O4)(NH3)4]2(S2O6) has no cytotoxic, clastogenic or genotoxic in vitro effects at concentrations less than or equal to 0.015 µM. This information proves as promising in the treatment of cancer and is crucial for future trials.

Efeitos do nitrosil rutênio na lesão cerebral induzida porisquemia e reperfusão em ratos

Efeitos do nitrosil rutênio na lesão cerebral induzida por isquemia e reperfusão em ratos. MARCIO WILKER SOARES CAMPELO. Pós-Graduação Stricto Sensu do Departamento de Cirurgia, Faculdade de Medicina, Universidade Federal do Ceará (Grau de Mestre em Cirurgia). Novembro, 2009. Orientador: Prof. Dr. Paulo Roberto Leitão de Vasconcelos. Introdução e objetivo: Doadores de NO podem diminuir a lesão neuronal durante a isquemia e reperfusão cerebral (I/R) por aumento do fluxo sanguíneo cerebral. O objetivo deste estudo é avaliar se um novo complexo de nitrosilo complexo de rutênio (Rut-bpy) capaz liberar NO direto na musculatura lisa vascular apresenta algum efeito durante I/R. Método: Foram utilizados 96 ratos machos, da linhagem Wistar, com peso médio de 290.27 g, distribuídos em 2 fases com 8 grupos cada: Fase de isquemia 4 grupos sham (SF, Rut-bpy,L-NAME e L-NAME+Rut-bpy) e 4 grupos isquemia (SF, Rut-bpy,L-NAME e L-NAME+Rut-bpy); da mesma forma foi dividido a fase de reperfusão ( 4 grupos sham e 4 grupos isquemia/reperfusão) com as mesmas drogas teste da fase de isquemia. Foi utilizado um modelo de isquemia cerebral global incompleta, com oclusão da artéria carótida comum bilateral e administração do SF, Rut-bpy e L-NAME via intraperitoneal. No final do experimento os animais foram decapitados e o cérebro fatiado para ser avaliado à área de lesão por histoquímica. Durante todo o experimento a PAM dos animais foi monitorizada...

Effects of nitrosyl ruthenium in injury brain induced by ischemia and reperfusion of rats.MARCIO WILKER SOARES CAMPELO. Stricto SensuPost-graduation. Department of Surgery, Medicine School, Federal University of Ceará (Degree of Master of Surgery). November, 2009. Advisor: Prof. Dr. Paulo Roberto Leitão de Vasconcelos. Background and purpose - Nitric oxide (NO) donors are known to reduce neuronal damage during brain ischemia and reperfusion by increasing the blood flow. Rut-bpy is a novel nitrosyl-ruthenium complex releasing NO directly into the vascular smooth musculature. The objective of the study was to evaluate the effect of Rut-bpy on a rat model of brain ischemia and reperfusion. Methods - Ninety-six male Wistar rats weighing approximately 290g were randomly assigned to 16 groups. Four groups and their respective sham groups were submitted to ischemia (Stage 1), while four groups and their respective sham groups were submitted to ischemia + reperfusion (Stage 2). At each stage of the experiment the groups were treated pairwise with saline solution (SS), Rut-bpy, L-NAME and L-NAME+Rut-bpy, respectively. The study was based on an incomplete global brain ischemia model with occlusion of the common bilateral carotid arteries and intraperitoneal administration of the study drugs. Following the experiment the animals were decapitated and the brain was sectioned for histochemical evaluation of the area of damage. The mean arterial blood pressure (MABP) was monitored throughout the experiment...

Estudo de propriedades físico-químicas de metalofármacos de dirutênio com anti-inflamatórios não esteroides / Study of physico-chemical properties of diruthenium metallodrugs with non-steroidal anti-inflammatory drugs

Complexos de rutênio, em razão da menor toxicidade e por poderem exibir atividade citotóxica ou antimetastática, tem sido considerados como alternativas potencialmente promissoras aos complexos de platina para tratamento de câncer. Nosso grupo de pesquisa tem investigado a interação de íons metálicos com fármacos anti-inflamatórios não esteroides (FAINEs) e já obteve sucesso na preparação de metalofármacos de dirutênio(II,III)-FAINEs, os quais se mostraram promissores com relação à atividade frente a modelos de glioma. Com a finalidade de contribuir para o entendimento das propriedades físico-químicas desses complexos, o presente trabalho teve como principal objetivo analisar propriedades consideradas particularmente essenciais a um potencial candidato a fármaco, tais como, estabilidade no estado sólido, lipofilicidade, solubilidade aquosa e dissolução intrínseca. Um complexo inédito de fórmula [Ru2Cl(feno)4], em que feno = fenoprofenato, foi sintetizado e caracterizado por meio de análise elementar, espectroscopia eletrônica, espectroscopia vibracional, difratometria de raios X, análise térmica e espectrometria de massas. Os complexos já testados anteriormente para atividade biológica, [Ru2Cl(ibp)4], ibp = ibuprofenato, e [Ru2(cet)4Cl], cet = cetoprofenato, foram analisados quanto à estabilidade no estado sólido por meio da determinação isotérmica de variação de massa. As lipofilicidades desses dois complexos, juntamente com a dos fármacos de origem e a do precursor sintético [Ru2(O2CH3)4Cl], foram avaliadas pelo método shake flask, e suas solubilidade aquosas foram investigadas em presença de co-solventes alcoólicos. Investigou-se ainda a velocidade de dissolução intrínseca do [Ru2Cl(ibp)4] que se encontra em estágio avançado de estudos biológicos. Os resultados obtidos trazem novas informações sobre o comportamento térmico dos complexos e sobre suas características biofarmacêutica

Ruthenium complexes, mainly due to the lower toxicity and the cytotoxic and anti-metastatic activities, have been considered as potentially promising alternatives to platinum drugs for cancer treatment. Our research group has investigated the interactions of diruthenium metal cores with anti-inflammatory non-steroidal drugs (NSAIDs) and succeeded in preparing diruthenium(II,III)-NSAIDs metallodrugs which show promising activity against glioma models. With the aim of elucidating the physico-chemical properties of these complexes, the major objective of the present work was to investigate properties which are considered as essential for a potential candidate to drug, e.g., stability in the solid state, lipophilicity, aqueous solubility and intrinsic dissolution. A new complex of formula [Ru2Cl(feno)4], where feno = fenoprofen, was synthesized and characterized by elemental analysis, electronic spectroscopy, vibrational spectroscopy, X-rays difractommetry, thermal analysis and mass spectrometry. The complexes previously tested for biological properties, [Ru2Cl(ibp)4], ibp = ibuprofenate, and [Ru2(cet)4Cl], cet = cetoprofenate, were inv estigated for the stability in the solid state by isothermal thermogravimetry. The lipophilicity of the se complexes, as well as those of the parent drugs and of the precursor [Ru2(O2CH3)4Cl], was evaluated by the shake flask method, and their aqueous solubility in the presence of alcohol co-solvents was investigated. In addition, the intrinsic dissolution rate was determined for [Ru2Cl(ibp)4], which is undergoing advanced biological studies. The results provide important new information on the thermal behavior of the complexes and also on their biopharmaceutical propertie

Clinical use of a ceramide-based moisturizer for treating dogs with atopic dermatitis

In humans, skin barrier dysfunction is thought to be responsible for enhanced penetration of allergens. Similar to conditions seen in humans, canine atopic dermatitis (CAD) is characterized by derangement of corneocytes and disorganization of intercellular lipids in the stratum corenum (SC) with decreased ceramide levels. This study was designed to evaluate the effects of a moisturizer containing ceramide on dogs with CAD. Dogs (n = 20, 3~8 years old) with mild to moderate clinical signs were recruited and applied a moisturizer containing ceramide for 4 weeks. Transepidermal water loss (TEWL), skin hydration, pruritus index for canine atopic dermatitis (PICAD) scores, and canine atopic dermatitis extent and severity index (CADESI) scores of all dogs were evaluated. Skin samples from five dogs were also examined with transmission electron microscopy (TEM) using ruthenium tetroxide. TEWL, PICAD, and CADESI values decreased (p < 0.05) and skin hydration increased dramatically over time (p < 0.05). Electron micrographs showed that the skin barrier of all five dogs was partially restored (p < 0.05). In conclusion, these results demonstrated that moisturizer containing ceramide was effective for treating skin barrier dysfunction and CAD symptoms.

Identification of mechanisms involved in the relaxation of rabbit cavernous smooth muscle by a new nitric oxide donor ruthenium compound

PURPOSE: The aim of this study was to evaluate the relaxation in vitro of cavernous smooth muscle induced by a new NO donor of the complex nitrosil-ruthenium, named trans-[Ru(NH3)4(caffeine)(NO)]C13 (Rut-Caf) and sodium nitroprusside (SNP). MATERIALS AND METHODS: The tissues, immersed in isolated bath systems, were pre-contracted with phenilephrine (PE) (1 µM) and then concentration-response curves (10-12 - 10-4 M) were obtained. To clarify the mechanism of action involved, it was added to the baths ODQ (10 µM, 30 µM), oxyhemoglobin (10 µM), L-cysteine (100 µM), hydroxicobalamine (100 µM), glibenclamide, iberotoxin and apamine. Tissue samples were frozen in liquid nitrogen to measure the amount of cGMP and cAMP produced. RESULTS: The substances provoked significant relaxation of the cavernous smooth muscle. Both Rut-Caf and SNP determined dose-dependent relaxation with similar potency (pEC50) and maximum effect (Emax). The substances showed activity through activation of the soluble guanylyl cyclase (sGC), because the relaxations were inhibited by ODQ. Oxyhemoglobin significantly diminished the relaxation effect of the substances. L-cysteine failed to modify the relaxations caused by the agents. Hydroxicobalamine significantly diminished the relaxation effect of Rut-Caf. Glibenclamide significantly increased the efficacy of Rut-Caf (pEC50 4.09 x 7.09). There were no alterations of potency or maximum effect of the substances with the addition of the other ion channel blockers. Rut-Caf induced production of significant amounts of cGMP and cAMP during the relaxation process. CONCLUSIONS: In conclusion, Rut-Caf causes relaxation of smooth muscle of corpus cavernosum by means of activation of sGC with intracellular production of cGMP and cAMP; and also by release of NO in the intracellular environment. Rut-Caf releases the NO free radical and it does not act directly on the potassium ion channels.

Nitric oxide synthesis and biological functions of nitric oxide released from ruthenium compounds

During three decades, an enormous number of studies have demonstrated the critical role of nitric oxide (NO) as a second messenger engaged in the activation of many systems including vascular smooth muscle relaxation. The underlying cellular mechanisms involved in vasodilatation are essentially due to soluble guanylyl-cyclase (sGC) modulation in the cytoplasm of vascular smooth cells. sGC activation culminates in cyclic GMP (cGMP) production, which in turn leads to protein kinase G (PKG) activation. NO binds to the sGC heme moiety, thereby activating this enzyme. Activation of the NO-sGC-cGMP-PKG pathway entails Ca2+ signaling reduction and vasodilatation. Endothelium dysfunction leads to decreased production or bioavailability of endogenous NO that could contribute to vascular diseases. Nitrosyl ruthenium complexes have been studied as a new class of NO donors with potential therapeutic use in order to supply the NO deficiency. In this context, this article shall provide a brief review of the effects exerted by the NO that is enzymatically produced via endothelial NO-synthase (eNOS) activation and by the NO released from NO donor compounds in the vascular smooth muscle cells on both conduit and resistance arteries, as well as veins. In addition, the involvement of the nitrite molecule as an endogenous NO reservoir engaged in vasodilatation will be described.

Treatability of resin effluents by electrochemical oxidation using batch recirculation reactor

Electro oxidation processes are developed throughout the world for ambient temperature destruction of organic wastes. Several of these processes are based on mediated electrochemical oxidation. This article presents the experimental results of electro chemical study based on mediated electrochemical oxidation process conducted for synthetic organic ion exchange resin materials. Investigation was carried out using the traditional noble metal oxide coated anode, ruthenium oxide-titanium and the mediator used for the experiment was ferrous sulphate, with sodium chloride as supporting electrolyte. The concentration of sodium chloride was maintained at 5, 8, 12 gm/L. The experiment was carried out in batch recirculation reactor with varied current densities for various flow rates. The study highlighted that in batch reactor set up the best effect of total organic content reduction was found to occur at 3.75 A/dm[2] with flow rate of 20 L/h. The simulated studies were carried out for different volumes of effluent and current densities. A graphical analysis was made between the experimental and simulated values and it was found that both the values are very close

Relaxation of rabbit corpus cavernosum smooth muscle and aortic vascular endothelium induced by new nitric oxide donor substances of the nitrosyl-ruthenium complex

INTRODUCTION: Endothelial dysfunction characterized by endogenous nitric oxide (NO) deficiency made 56 percent of patients affected with erectile dysfunction decline treatment with PDE-5 inhibitors. New forms of treatment are currently being developed for this group of patients. MATERIALS AND METHODS: The study compared the effect of sodium nitroprusside (SNP) and two substances of the nitrosyl-ruthenium complex, cis-[Ru(bpy)2(SO3)(NO)]PF-6-9 ("FONO1”) and trans-[Ru(NH3)4(caffeine)(NO)]C13 ("LLNO1”) on relaxation of rabbit corpus cavernosum smooth muscle and aortic vascular endothelium. The samples were immersed in isolated baths and precontracted with 0.1 µM phenylephrine (PE) and the corresponding relaxation concentration/response curves were plotted. In order to investigate the relaxation mechanisms involved, 100 µM ODQ (a soluble guanylate cyclase-specific inhibitor), 3 µM or 10 µM oxyhemoglobin (an extracellular NO scavenger) or 1 mM L-cysteine (a nitrosyl anion-specific scavenger) was added to the samples. RESULTS: All the NO donors tested produced a significant level of relaxation in the vascular endothelium. In corpus cavernosum samples, FONO1 produced no significant effect, but LLNO1 and SNP induced dose-dependent relaxation with comparable potency (pEC50 = 6.14 ± 0.08 and 6.4 ± 0.14, respectively) and maximum effect (Emax = 82 percent vs. 100 percent, respectively). All NO donors were found to activate soluble guanylate cyclase, since the addition of the corresponding inhibitor (100 µM ODQ) completely neutralized the relaxation effect observed. The addition of oxyhemoglobin reduced the relaxation effect, but did not inhibit it completely. In aortic vascular endothelium 3 µM oxyhemoglobin decreased the relaxation effect by 26 percent on the average, while 10 µM oxyhemoglobin reduced it by over 52 percent. The addition of 100 µM L-cysteine produced no significant inhibiting effect. CONCLUSIONS: These results suggest that LLNO1...

Plaque radiotherapy in recurrent or incomplete-excised conjunctival squamous cell carcinoma and melanoma

To assess the results of brachytherapy in patients with recurrent or incomplete excised conjunctival squamous cell carcinoma [SCC] and malignant melanoma. Three patients underwent brachytherapy of one eye and one patient underwent brachytherapy of both eyes with ruthenium-106 [RU-106] plaques, all of them had a history of incomplete resection or recurrence of the tumor after surgery. All patients were male with an average age at diagnosis of 54 years [range, 34-76 years].The shape and the size of plaques were determined based on location and size of the suspected area. The plaque was inserted to deliver a target dose of 80-100 Gy in the region of conjunctival malignancy. The diagnosis was squamous cell carcinoma in three eyes and conjunctival melanoma in two eyes. All patients had surgical history of one to three previous excisions with or without cryotherapy before brachytherapy. There were microscopic residual tumors after excision in 2 eyes and recurrent lesion was evident in 3 other eyes. A mean dose of 95 Gy was delivered to the tumor bed. Complete tumor regression without any evidence of recurrent lesion was obtained in all five eyes. The patients were followed for 32 months on average [range, 18-42 months]. No radiation related complication was detected, with an exception of a dry eye in the last follow up. Brachytherapy with RU-106 plaque is an alternative method for treatment of selected patients with recurrent or residual conjunctival SCC and melanoma

Anti-HIV and cytotoxic ruthenium(II) complexes containing flavones: biochemical evaluation in mice.

Ru(II) polypyridyl complexes containing 3-hydroxyflavone derivatives as coligands were screened for anti-HIV and cytotoxic activities against eleven tumor cell lines. In order to check the effect of flavones containing Ru(II) complexes in vivo on a mammal, a representative complex Ru(L)2(DMSO)2 x 5H2O (LH-3-Hdroxy-4'-benzyloxyflavone; M5) was orally administered to adult male mice. Its effects on protein content and LDH were studied in different tissues of the animal. The compound got absorbed and retained in the blood between 1-3 hr after feeding. As compared to the normal and DMSO control sets, tissue specific significant reversible changes in the protein content as well as in LDH activity were observed between 1-4 hr of treatment. However, on polyacrylamide gel electrophoresis, except some tissue specific transitory alterations, expression patterns of five LDH isozymes were unchanged after feeding the compound. The present results suggested that in addition to its potent cytotoxic and anti-HIV effects on cell lines in vitro, M5 inhibited LDH activity, but reversibly with a little effect on biosynthetic status of the enzyme in mice.

Topoisomerase II poisoning by indazole and imidazole complexes of ruthenium.

Trans-imidazolium (bis imidazole) tetrachloro ruthenate (RuIm) and trans-indazolium (bis indazole) tetrachloro ruthenate (RuInd) are ruthenium coordination complexes, which were first synthesized and exploited for their anticancer activity. These molecules constitute two of the few most effective anticancer ruthenium compounds. The clinical use of these compounds however was hindered due to toxic side effects on the human body. Our present study on topoisomerase II poisoning by these compounds shows that they effectively poison the activity of topoisomerase II by forming a ternary cleavage complex of DNA, drug and topoisomerase II. The thymidine incorporation assays show that the inhibition of cancer cell proliferation correlates with topoisomerase II poisoning. The present study on topoisomerase II poisoning by these two compounds opens a new avenue for renewing further research on these compounds. This is because they could be effective lead candidates for the development of more potent and less toxic ruthenium containing topoisomerase II poisons. Specificity of action on this molecular target may reduce the toxic effects of these ruthenium-containing molecules and thus improve their therapeutic index.

Thin molecular films of supramolecular porphyrins

A relevant series of symmetric supramolecular porphyrins has been obtained by attaching four [RuII(bipy)2Cl] groups to the pyridyl substituents of meso-tetra(4-pyridyl)porphyrin and its metallated derivatives. These compounds display a rich electrochemistry and versatile catalytic, electrocatalytic and photochemical properties, associated with the ruthenium-bipyridine and the porphyrin complexes. These properties can be transferred to the electrodes by attaching thin molecular films of the compounds, by dip-coating, electrostatic assembly or electropolymerization. In this way, the interesting properties of those supermolecules and supramolecular assemblies can be used to prepare molecular devices and sensors

Supramolecular effects in dentritic systems containing photoactive groups

In this article are described dendritic structures containing photoactive groups at the surface or in the core. The observed supramolecular effects can be attributed to the nature of the photoactive group and their location in the dendritic architecture. The peripheric azobenzene groups in these dendrimeric compounds can be regarded as single residues that retain the spectroscopic and photochemical properties of free azobenzene moiety. The E and Z forms of higher generation dendrimer, functionalized with azobenzene groups, show different host ability towards eosin dye, suggesting the possibility of using such dendrimer in photocontrolled host-guest systems. The photophysical properties of many dendritic-bipyridine ruthenium complexes have been investigated. Particularly in aerated medium more intense emission and a longer excited-state lifetime are observed as compared to the parent unsubstituted bipyridine ruthenium complexes. These differences can be attributed to a shielding effect towards dioxygen quenching originated by the dendritic branches

Molecular mechanics aided design of antineoplastic agents from ruthenium coordinate complexes.

Through energy minimization using molecular mechanics force field four ruthenium cordinate complexes have been synthesized. Compound I to IV showed antineoplastic activity with varying degree on EAC bearing mice. Mode of action may be through inhibition of antioxidant property of tumor cell as evident from lipid peroxidase activity. Among the complexes Bis pyridine tetrachloro ruthenium exhibits highest order of activity with respect to increase mean survival time, inhibition of tumour volume, total blood count, hemoglobin and lipid peroxidase activity.