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1.
Pharmacogenomics J ; 18(1): 56-63, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-27958379

RESUMO

This study was designed to investigate the mode of action of trabectedin in myelomonocytic leukemia cells by applying systems biology approaches to mine gene expression profiling data and pharmacological assessment of the cellular effects. Significant enrichment was found in regulons of target genes inferred for specific transcription factors, among which MAFB was the most upregulated after treatment and was central in the transcriptional network likely to be relevant for the specific therapeutic effects of trabectedin against myelomonocytic cells. Using the Connectivity Map, similarity among transcriptional signatures elicited by treatment with different compounds was investigated, showing a high degree of similarity between transcriptional signatures of trabectedin and those of the topoisomerase I inhibitor, irinotecan, and an anti-dopaminergic antagonist, thioridazine. The study highlights the potential importance of systems biology approaches to generate new hypotheses that are experimentally testable to define the specificity of the mechanism of action of drugs.


Assuntos
Antineoplásicos Alquilantes/uso terapêutico , Leucemia Mieloide/tratamento farmacológico , Trabectedina/farmacologia , Linhagem Celular Tumoral , Perfilação da Expressão Gênica/métodos , Redes Reguladoras de Genes/efeitos dos fármacos , Humanos , Biologia de Sistemas/métodos , Transcrição Gênica/efeitos dos fármacos
2.
Ann Oncol ; 27(8): 1511-9, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27194815

RESUMO

BACKGROUND: Clinical and pathological parameters of patients with epithelial ovarian cancer (EOC) do not thoroughly predict patients' outcome. Despite the good outcome of stage I EOC compared with that of stages III and IV, the risk assessment and treatments are almost the same. However, only 20% of stage I EOC cases relapse and die, meaning that only a proportion of patients need intensive treatment and closer follow-up. Thus, the identification of cell mechanisms that could improve outcome prediction and rationalize therapeutic options is an urgent need in the clinical practice. PATIENTS AND METHODS: We have gathered together 203 patients with stage I EOC diagnosis, from whom snap-frozen tumor biopsies were available at the time of primary surgery before any treatment. Patients, with a median follow-up of 7 years, were stratified into a training set and a validation set. RESULTS AND CONCLUSIONS: Integrated analysis of miRNA and gene expression profiles allowed to identify a prognostic cell pathway, composed of 16 miRNAs and 10 genes, wiring the cell cycle, 'Activins/Inhibins' and 'Hedgehog' signaling pathways. Once validated by an independent technique, all the elements of the circuit resulted associated with overall survival (OS) and progression-free survival (PFS), in both univariate and multivariate models. For each patient, the circuit expressions have been translated into an activation state index (integrated signature classifier, ISC), used to stratify patients into classes of risk. This prediction reaches the 89.7% of sensitivity and 96.6% of specificity for the detection of PFS events. The prognostic value was then confirmed in the external independent validation set in which the PFS events are predicted with 75% sensitivity and 94.7% specificity. Moreover, the ISC shows higher classification performance than conventional clinical classifiers. Thus, the identified circuit enhances the understanding of the molecular mechanisms lagging behind stage I EOC and the ISC improves our capabilities to assess, at the time of diagnosis, the patient risk of relapse.


Assuntos
Biomarcadores Tumorais/genética , Regulação Neoplásica da Expressão Gênica/genética , Neoplasias Epiteliais e Glandulares/genética , Neoplasias Ovarianas/genética , Prognóstico , Adulto , Idoso , Carcinoma Epitelial do Ovário , Intervalo Livre de Doença , Feminino , Humanos , MicroRNAs/genética , Análise em Microsséries , Pessoa de Meia-Idade , Proteínas de Neoplasias/genética , Estadiamento de Neoplasias , Neoplasias Epiteliais e Glandulares/patologia , Neoplasias Ovarianas/patologia
3.
Ann Oncol ; 27(4): 625-34, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26782955

RESUMO

BACKGROUND: Neoadjuvant chemotherapy (NACT) has been recognized as a reliable therapeutic strategy in patients with unresectable advanced epithelial ovarian cancer (EOC). The molecular events leading to platinum (Pt) response in NACT settings have hitherto not been explored. In the present work, longitudinal changes of miRNA expression profile were investigated to identify miRNA families with prognostic role in high-grade serous EOC patients who received the NACT regimen. PATIENTS AND METHODS: One hundred sixty-four matched tumor biopsies taken at initial laparoscopic evaluation and at interval-debulking surgery (IDS) after four courses of Pt-based therapy were selected from 82 stage IIIC-IV high-grade serous-EOC patients that were judged unsuitable for complete primary debulking and subjected the NACT protocol. miRNA profiling by microarray, real-time PCR and immuno-histochemical staining for Smad2 phosphorylation (P-Smad2) were used for data analysis. RESULTS: Analysis revealed that 369 miRNAs were differentially expressed in matched biopsies (referred to as DEMs). DEMs were not scattered across the genome, but clustered into families: miR-199, let-7, miR-30, miR-181 and miR-29. Multivariate analysis showed that miR-199a-3p, miR-199a-5p, miR-181a-5p and let-7g-5p associated with overall and progression-free survival (P < 0.05); miR-199a-3p, miR-199a-5p and miR-181a-5p associated with residual tumor volume and Pt-free interval (P < 0.05). Immuno-histochemical staining confirmed an enrichment of P-Smad2, a marker of transforming growth factor-ß activation, in tumors from patients with shorter PFS and OS, and with high levels of expression of miR-181a-5p (P < 0.05). Kaplan-Meier curves plotting concomitant expression of P-Smad2 and miR-181a-5p show significant differences in PFS and OS compared with those depicting the expression of each biomarker alone (P < 0.001). CONCLUSIONS: This study describes several miRNA families with a prognostic role in the NACT setting. It also confirms that concomitant analysis of P-Smad2 and miR-181a-5p in surgical samples may be capable of identifying those ovarian cancer patients with poor outcome and little chance of response to Pt-based NACT.


Assuntos
Cistadenocarcinoma Seroso/tratamento farmacológico , MicroRNAs/biossíntese , Terapia Neoadjuvante , Neoplasias Ovarianas/tratamento farmacológico , Proteína Smad2/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Biomarcadores Tumorais/biossíntese , Biomarcadores Tumorais/genética , Biópsia , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/patologia , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , MicroRNAs/genética , Pessoa de Meia-Idade , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Prognóstico , Proteína Smad2/genética
4.
Oral Implantol (Rome) ; 9(Suppl 1/2016 to N 4/2016): 65-70, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28280534

RESUMO

Modern implantology is based on the use of endosseous dental implants and on the study of osseointegration processes. The loss of marginal bone around a dental implant can be caused by many factors; the proper distribution of the masticatory loads is important and is closely dependent on the quality and quantity of bone tissue surrounding the implant. In fact, bone has the ability to adapt its microstructure, through processes of resorption and neoformation of new bone matrix, as a result of the mechanical stimuli that are generated during the chewing cycles. The purpose of this article is to redefine in a modern key and in light of current industrial and engineering technology, clinical and biomechanical concepts that characterize the monophasic implants, in order to assess proper use by evaluating the biomechanical differences with the biphasic implants.

5.
Ann Oncol ; 26(7): 1363-71, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25846551

RESUMO

BACKGROUND: The majority of patients with stage III-IV epithelial ovarian cancer (EOC) relapse after initially responding to platinum-based chemotherapy, and develop resistance. The genomic features involved in drug resistance are unknown. To unravel some of these features, we investigated the mutational profile of genes involved in pathways related to drug sensitivity in a cohort of matched tumors obtained at first surgery (Ft-S) and second surgery (Sd-S). PATIENTS AND METHODS: Matched biopsies (33) taken at Ft-S and Sd-S were selected from the 'Pandora' tumor tissue collection. DNA libraries for 65 genes were generated using the TruSeq Custom Amplicon kit and sequenced on MiSeq (Illumina). Data were analyzed using a high-performance cluster computing platform (Cloud4CARE project) and independently validated. RESULTS: A total of 2270 somatic mutations were identified (89.85% base substitutions 8.19% indels, and 1.92% unknown). Homologous recombination (HR) genes and TP53 were mutated in the majority of Ft-S, while ATM, ATR, TOP2A and TOP2B were mutated in the entire dataset. Only 2% of mutations were conserved between matched Ft-S and Sd-S. Mutations detected at second surgery clustered patients in two groups characterized by different mutational profiles in genes associated with HR, PI3K, miRNA biogenesis and signal transduction. CONCLUSIONS: There was a low level of concordance between Ft-S and Sd-S in terms of mutations in genes involved in key processes of tumor growth and drug resistance. This result suggests the importance of future longitudinal analyses to improve the clinical management of relapsed EOC.


Assuntos
Adenocarcinoma de Células Claras/genética , Adenocarcinoma Mucinoso/genética , Cistadenocarcinoma Seroso/genética , Neoplasias do Endométrio/genética , Genes Neoplásicos/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Mutação/genética , Neoplasias Ovarianas/genética , Adenocarcinoma de Células Claras/mortalidade , Adenocarcinoma de Células Claras/secundário , Adenocarcinoma de Células Claras/terapia , Adenocarcinoma Mucinoso/mortalidade , Adenocarcinoma Mucinoso/secundário , Adenocarcinoma Mucinoso/terapia , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biópsia , Terapia Combinada , Cistadenocarcinoma Seroso/mortalidade , Cistadenocarcinoma Seroso/secundário , Cistadenocarcinoma Seroso/terapia , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias do Endométrio/mortalidade , Neoplasias do Endométrio/secundário , Neoplasias do Endométrio/terapia , Feminino , Seguimentos , Recombinação Homóloga , Humanos , Estudos Longitudinais , Metástase Linfática , Pessoa de Meia-Idade , Gradação de Tumores , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/mortalidade , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/terapia , Estadiamento de Neoplasias , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/terapia , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
6.
J Mech Behav Biomed Mater ; 40: 127-139, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25222871

RESUMO

Fiber-reinforced composites (FRC) could be feasible materials for fracture fixation devices if the mechanical properties of the composites are congruent with the local structural properties of bone. In a recently developed FRC implant, bisphenol A dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) resin was reinforced with unidirectional E-glass fibers. The addition of a braided glass fiber sleeving to the unidirectional fibers increased the torsional strength (99.5MPa) of the FRC implants at the expense of the flexural strength (602.0MPa). The flexural modulus was 15.3GPa. Two types of FRC intramedullary nails were prepared; first type was FRC as such, second type was FRC with a surface layer of bioactive glass (BG) granules. Experimental oblong subtrochanteric defect was created in 14 rabbits. The defect, which reduced the torsional strength of the bones by 66%, was fixed with an FRC intramedullary nail of either type. The contralateral intact femur served as the control. This model simulated surgical stabilization of bone metastasis. After 12 weeks of follow-up, the femurs were harvested and analyzed by torsional testing, micro-CT and hard tissue histology. Healed undisplaced peri-implant fractures were noticed in half of the animals irrespective of the type of FRC implant. Torsional testing showed no significant differences between the implantation groups. The torsional strength of the bones stabilized by either type of FRC implant was 83% of that of the contralateral femurs. In histological analysis, no implant debris and no adverse tissue reactions were observed. While the mechanical properties of the modified FRCs were suboptimal, the FRC intramedullary nails supported the femurs without structural failure, even in the cases of peri-implant fractures.


Assuntos
Compostos Benzidrílicos/química , Pinos Ortopédicos , Teste de Materiais , Fenômenos Mecânicos , Metacrilatos/química , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Suporte de Carga , Animais , Fêmur/diagnóstico por imagem , Fêmur/fisiologia , Masculino , Coelhos , Relação Estrutura-Atividade , Microtomografia por Raio-X
7.
Minerva Stomatol ; 59(6): 305-13, 2010 Jun.
Artigo em Inglês, Italiano | MEDLINE | ID: mdl-20588217

RESUMO

AIM: The aim of the present study was to analyze stress and strain distribution in dental implants with different abutment's inclination inserted in D1 and D4 bone. METHODS: The biomechanical behavior of 5 mm x 16 mm dental implants with straight, 15 degrees and 25 degrees angulated abutments subjected to static loads, in contact with D1 and D4 bone, was evaluated by Finite Element Analysis (FEA). RESULTS: The lowest stress and strain values were found in the system composed by implants with straight abutments loaded with a 200-N vertical strength, while the highest stress and strain values were found in implants with 15 degrees angulated abutment loaded with a tilted strength (FY=200 N and FZ=140 N). Stress value increased from D1 to D4 bone, while strain value decreased due to the effect of normal elasticity mode of biological tissues. CONCLUSION: The different stress and strain distribution in D1 and D4 bone tissue surrounding dental implants with a tapered neck could favor prosthetic load and play a role in implant long-term success.


Assuntos
Implantes Dentários , Fenômenos Biomecânicos , Dente Suporte , Implantação Dentária Endóssea/métodos , Planejamento de Prótese Dentária , Análise de Elementos Finitos , Estresse Mecânico
8.
Eur J Paediatr Dent ; 8(4): 173-8, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18163851

RESUMO

AIM: This study was carried out with the purpose to show on a virtual model of oral cavity the mechanical behaviour of different kinds of pacifiers with different pressure levels that can be likened to a condition of rest and deglutition. MATERIALS AND METHODS: Three different types of dummies, orthodontic- (A), cherry- (B) and drop- (C) shaped from an anatomical point of view, were inserted between the palate and the tongue in a virtual system by means of a finite element simulation. The palatal structure was recreated through tridimensional laser scanning, while the tongue structure was reconstructed by a software suitable for reproducing solids. Also the image of the pacifiers was developed by computer-aided scanning and reproduction. Suitable constraints were inserted and high and low pressure levels were exerted on these systems. FEA simulation allowed us to distribute the strain on the palate according to the different geometrical structures of the objects. RESULTS: Dummy A shows a more uniform and wider crosswise stress distribution with also a lesser load on the anterior palatal crest. Dummy B and C, on the contrary, show a more dot-like behaviour inducing a higher stress due to contact on restricted points. CONCLUSION: The characteristics of dummy A, although they have not been clinically investigated yet, seem to be the fittest ones to guarantee the maintenance of the transversal diameters of the premaxilla and reduce the risk of open bite.


Assuntos
Simulação por Computador , Análise do Estresse Dentário/métodos , Análise de Elementos Finitos , Modelos Dentários , Chupetas , Fenômenos Biomecânicos/métodos , Arco Dental/anatomia & histologia , Desenho de Equipamento , Humanos , Imageamento Tridimensional , Manequins , Maxila/anatomia & histologia , Desenvolvimento Maxilofacial , Mordida Aberta/prevenção & controle , Aparelhos Ortodônticos , Palato/anatomia & histologia , Comportamento de Sucção , Propriedades de Superfície , Língua/anatomia & histologia
9.
Biochim Biophys Acta ; 1502(3): 363-79, 2000 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-11068179

RESUMO

Using (13)C NMR, we tested the hypothesis that protection by preconditioning is associated with reduced glycogenolysis during ischemia. Preconditioned rat hearts showed improved postischemic function and reduced ischemic damage relative to ischemic controls after 30 min stop-flow ischemia and 30 min reperfusion (contractility: 30+/-10 vs. 2+/-2%; creatine kinase release: 41+/-4 vs. 83+/-15 U/g; both P<0.05). Preconditioning decreased preischemic [(13)C]glycogen by 24% (a 10% decrease in total glycogen), and delayed ischemic [(13)C]glycogen consumption by 5-10 min, reducing ischemic glycogenolysis without changing acidosis relative to controls. Upon reperfusion, glycogen synthesis resumed only after preconditioning. Glutamate (13)C-isotopomer analysis showed recovery of Krebs cycle activity with higher anaplerosis than before ischemia (23+/-4 vs. 11+/-3%, P<0.05), but in controls reperfusion failed to restore flux. Compared to control, preconditioning before 20 min ischemia increased contractility (86+/-10 vs. 29+/-14%, P<0.05) and restored preischemic anaplerosis (13+/-3 vs. 39+/-9%, P<0.05). Preconditioning is associated with reduced glycogenolysis early during ischemia. However, protection does not rely on major variations in intracellular pH, as proposed earlier. Our isotopomer data suggest that preconditioning accelerates metabolic and functional recovery during reperfusion by more efficient/active replenishment of the depleted Krebs cycle.


Assuntos
Glicogênio/metabolismo , Coração/fisiologia , Isquemia Miocárdica/metabolismo , Alanina/análise , Animais , Ciclo do Ácido Cítrico , Ácido Glutâmico/análise , Glicogênio/biossíntese , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Ácido Láctico/análise , Espectroscopia de Ressonância Magnética , Masculino , Contração Miocárdica , Reperfusão Miocárdica , Ratos , Ratos Sprague-Dawley , Extratos de Tecidos/metabolismo
10.
J Biomed Mater Res ; 50(3): 381-7, 2000 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-10737880

RESUMO

It is well known that osteolysis induced by polyethylene wear debris is the main cause of long-term failure of hip and knee prostheses. We developed a treatment of medical-grade ultra-high molecular-weight polyethylene (UHMWPE) in order to improve its tribologic properties and reduce its wear. Medical-grade UHMWPE was irradiated with a 200 kGy dose of radiation, thermally stabilized at a temperature close to the melting point, and then sterilized with ethylene oxide. The irradiation treatment was performed to crosslink the UHMWPE. The thermal stabilization treatment, contributing to the reaction between the free radicals generated by the irradiation process, was chosen to enhance crosslinking and to prevent oxidation and the shortening of chains. The non-invasive sterilization process with ethylene oxide was chosen to prevent the re-formation of free radicals. The wear performance of this material was compared to UHMWPE, untreated or treated with different sterilization techniques, using gamma and beta irradiation. Insoluble crosslinked constituents were measured with an extraction method. Wear was evaluated using a flat-on-ring wear test machine. While small differences were found among the different sterilization processes, 200 kGy-irradiated UHMWPE followed by thermal treatment and sterilization with ethylene oxide had the least wear and the greatest amount of crosslinking.


Assuntos
Materiais Biocompatíveis , Prótese Articular , Polietilenos , Reagentes de Ligações Cruzadas , Humanos , Propriedades de Superfície
11.
Cardioscience ; 5(2): 101-6, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7919046

RESUMO

The development of delayed doxorubicin cardiomyopathy in the rat is accompanied by profound anorexia, dramatically reducing the caloric intake. To assess the contribution of a restriction in food to the alterations in cardiac function, animals treated with doxorubicin were compared with a group of pair-fed control animals and with a second group of controls with unrestricted access to food. Prolongation of the Q alpha T interval of the electrocardiogram developed in rats treated with doxorubicin, but not in pair-fed controls. Myofibrillar ATPase activity and the contractile strength of isolated papillary muscles were depressed in rats treated with doxorubicin, but not in pair-fed rats. The reduction in ventricular weight was proportional to the reduction in the body weight in pair-fed rats, whereas a higher ratio of ventricular to body weight was observed in rats treated with doxorubicin. These results indicate that the alterations in cardiac function observed in delayed doxorubicin cardiomyopathy are not due to a reduction in the intake of food.


Assuntos
Cardiomiopatias/induzido quimicamente , Doxorrubicina/toxicidade , Ingestão de Alimentos , Coração/efeitos dos fármacos , Miocárdio/metabolismo , Adenosina Trifosfatases/metabolismo , Análise de Variância , Animais , Cardiomiopatias/enzimologia , Cardiomiopatias/fisiopatologia , Eletrocardiografia , Feminino , Coração/fisiologia , Modelos Biológicos , Miocárdio/enzimologia , Tamanho do Órgão , Ratos , Ratos Sprague-Dawley , Hormônios Tireóideos/sangue , Redução de Peso
12.
Free Radic Biol Med ; 16(2): 283-8, 1994 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8005524

RESUMO

The involvement of Se enzymes in the protection against the oxidative stress induced by adriamycin (ADR) in rat heart has been studied in animals fed for 10 weeks at three different levels of Se content (low = 0.02 ppm; normal = 0.5 ppm; high = 1.0 ppm) and receiving a weekly injection of 3 mg/kg ADR for 4 weeks. ECG (QaT duration) and contractility of isolated atria were measured. The high-Se diet showed a significant protection on both parameters. To assess the hypothesis that an increase of specific activity of antioxidant Se enzymes may account for the cardioprotective effect of selenium, glutathione peroxidase (GPX), and phospholipid hydroperoxide glutathione peroxidase (PHGPX) were tested. The assays were performed on ventricles isolated from treated rats. At the end of the experimental period, GPX (cytosolic enzyme) did not show any significant difference between controls and ADR-treated at any level of Se content, thus excluding its involvement in the cardioprotection observed in high-Se ADR-treated animals. PHGPX, which is present both in cytosol and in the cell membrane, showed a trend to increase its activity in the presence of ADR treatment only in the membrane fraction; however, the statistical significance was reached only in the low-Se group (+100%). This observation suggests that membrane PHGPX might be involved in the cellular mechanism of adaptation of the heart to the toxic effects of ADR; however, the behavior of these enzymes does not seem to account for the significant protection of selenium supplementation both on ECG and on contractile indices of ADR cardiotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Doxorrubicina/toxicidade , Eletrocardiografia/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Coração/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Miocárdio/enzimologia , Selênio/farmacologia , Animais , Membrana Celular/enzimologia , Citosol/enzimologia , Dieta , Feminino , Coração/fisiologia , Técnicas In Vitro , Miocárdio/patologia , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , Ratos , Ratos Sprague-Dawley , Selênio/administração & dosagem , Fatores de Tempo
13.
Anticancer Res ; 13(5A): 1607-12, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8239541

RESUMO

The possibility of preventing the myelo- and cardiotoxicity of adriamycin (ADR), was explored in in vivo experiments in the rat. Assuming that free radicals play a key role in the ADR organotoxicity, a new anti-radical approach was set up by administering a spin trapping compound (PBN) which is taken up by the cells and specifically interacts with radicals. ADR was given i.v., 3 mg/kg every 3rd day for 3 times. PBN was continuously administered throughout the persistence time of ADR in myocardium (15 days). Serial ECG and leukocyte counting were performed during 10 weeks, then hearts were isolated and Langendorff-perfused; functional parameters (heart rate, contractility, coronary flow) were evaluated. PBN improved ECG and prevented the myelotoxicity, while functional parameters were not significantly different from those of control. Cytotoxicity was evaluated in vitro in 3 different human tumour cell lines; PBN did not modify the cytotoxicity of ADR, thus excluding a free radical involvement in this activity. The present results suggest that a proper administration schedule of spin traps might be a promising approach for improving the therapeutic index of ADR.


Assuntos
Medula Óssea/efeitos dos fármacos , Doxorrubicina/efeitos adversos , Coração/efeitos dos fármacos , Óxidos de Nitrogênio/farmacologia , Marcadores de Spin , Animais , Relação Dose-Resposta a Droga , Doxorrubicina/farmacologia , Eletrocardiografia/efeitos dos fármacos , Espectroscopia de Ressonância de Spin Eletrônica , Feminino , Radicais Livres , Contagem de Leucócitos/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley
14.
Eur J Pharmacol ; 234(1): 113-6, 1993 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-8472754

RESUMO

The role and site of free radical generation in myocardial ischemia/reperfusion injury were investigated using the hydrophilic spin trapping agent, 5,5-dimethyl-1-pyrroline-1-oxide (DMPO). DMPO (40 mM) proved ineffective in preserving the contractile performance and energy metabolism of Langendorff-perfused rat hearts following ischemia and reperfusion. This result, which is in contrast with the cardioprotection observed with hydrophobic spin traps, suggests that free radicals are generated intracellularly under these conditions.


Assuntos
Óxidos N-Cíclicos/farmacologia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Marcadores de Spin , Animais , Metabolismo Energético/efeitos dos fármacos , Radicais Livres/metabolismo , Técnicas In Vitro , Masculino , Contração Miocárdica/efeitos dos fármacos , Traumatismo por Reperfusão Miocárdica/metabolismo , Ratos , Ratos Sprague-Dawley
15.
Ann Nutr Metab ; 37(6): 289-94, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8109887

RESUMO

Our work on isolated rat intestine aimed at studying the hypothesis that the intestinal transport of manganese was carrier-mediated and, consequently, subjected to saturation. Our results confirm this hypothesis, assessing the concentration of carrier saturation for manganese at 0.5 mM. As this concentration, which may determine self-limitation in the intestinal absorption of this metal, is much higher than the maximal allowed concentration of the EEC Standard (50 mg/l), food and water should be carefully monitored for their manganese content in order to avoid reaching toxic concentrations in blood and tissues.


Assuntos
Absorção Intestinal , Manganês/metabolismo , Animais , Feminino , Cinética , Ratos , Ratos Sprague-Dawley
16.
Biomed Mater Eng ; 3(3): 127-36, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8193564

RESUMO

Using Air Plasma Spraying (APS) and Vacuum Plasma Spraying (VPS) techniques, hydroxylapatite (HA) and mixtures of HA and titanium (Ti) were deposited on a Ti6A14V alloy (and on an AISI 316L steel) subjected to different surface treatments. The deposits were investigated for their crystallinity, thickness, and adhesion properties. Higher adhesion values were obtained with VPS rather than with APS. By utilising VPS, the deposition conditions were selected in order to achieve crystallinity values between 70 and 90%. The adhesion results depend on the crystallinity (increasing with its decrease), on the thickness (decreasing slightly with its increase) and especially on the surface finish of the metallic substrate. A porous Ti precoat was more effective than either chemical etching in HCl or sandblasting; sandblasting being the least effective. In particular, the double deposits consisting of a porous Ti precoat and a successive layer of HA proved to be most interesting for their higher adhesion properties and for their capability of providing primary stability due to the presence of the HA and secondary stability, in the case of its reabsorption, due to the porous metal.


Assuntos
Ligas , Cimentos Ósseos/normas , Durapatita/normas , Prótese Articular , Titânio , Titânio/normas , Cimentos Ósseos/química , Cristalização , Durapatita/química , Teste de Materiais , Osseointegração , Porosidade , Propriedades de Superfície , Resistência à Tração , Titânio/química , Vácuo
17.
Pharmacol Res ; 26(2): 143-50, 1992 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1409255

RESUMO

The role of free radical generation in the development of the acute cardiotoxicity induced by doxorubicin (DXR) in the rat and the protective activity of anti-radical drugs were investigated in in vivo experiments by evaluating the body weight curve, ECG, contractile performance and coronary flow up to 10 days after DXR. A lipophilic spin trap (alpha-phenyl-tert-butyl nitrone, PBN) was continuously administered at a dose of 0.65 mg/kg every hour for 2 weeks by an intraperitoneal osmotic pump. DXR was administered i.v. at a dose of 9 mg/kg 3 days after beginning the PBN infusion. DXR impaired ECG and body weight gain after 3 days (partly reversible at later times), while contractility and coronary flow were significantly impaired throughout the experimental time. PBN was shown to prevent the DXR-induced alterations of contractility and coronary flow, while ECG was non-significantly improved. The body weight curve was not affected. Since the dose of PBN used does not produce pharmacological effects, the protective activity in rats receiving DXR indicates that free radicals may play a causal role in the acute cardiotoxicity in vivo. The use of suitable spin traps and administration schedules seems to be an interesting approach for the prevention of radical-dependent pathologies.


Assuntos
Cardiopatias/prevenção & controle , Óxidos de Nitrogênio/farmacologia , Animais , Peso Corporal/efeitos dos fármacos , Óxidos N-Cíclicos , Doxorrubicina , Eletrocardiografia/efeitos dos fármacos , Feminino , Radicais Livres , Cardiopatias/induzido quimicamente , Hemodinâmica/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Óxidos de Nitrogênio/administração & dosagem , Ratos , Ratos Sprague-Dawley , Marcadores de Spin
18.
J Mol Cell Cardiol ; 24(4): 375-86, 1992 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1619668

RESUMO

The aim of this work was to ascertain whether free radicals play a causal role in the injury occurring in myocardial ischemia and reperfusion. To this purpose we observed whether spin-trapping compounds protect the heart when used at a concentration capable of reacting with free radicals. The lipophilic spin trap alpha-phenyl-t-butyl nitrone (PBN) was used because it is taken up by the myocites. Isolated Langendorff rat hearts were subjected to ischemia according to two schemes: "Model A" = 30 min zero-flow ischemia followed by 30 min reperfusion; "Model B" = 60 min of low-flow ischemia (10% of the individual value; N2 saturated) followed by 30 min reperfusion. Treated groups received in addition 5.0 mM PBN which was supplied continuously. The following parameters were measured throughout the experiment: contractile performance (RPP); coronary flow (CF); CPK; phosphocreatine (PCr), ATP, inorganic phosphate (Pi), intracellular pH (pHi). The pathology obtained by "Model A" is more severe than that of Model B, and partly irreversible. During the ischemic phase in "Model A", contractility, PCr and ATP dropped to near zero; during initial reflow CPK rose about 13-fold and Pi rose 2.5-fold, while pHi decreased to 6.1. During reperfusion, a partial recovery of PCr, Pi and pHi was observed, while RPP and ATP did not increase; PBN treatment improved significantly PCr and CPK, while the other parameters were unaffected. During ischemia, "Model B" hearts showed a drop of contractility to near zero, of PCr to 35%, of ATP to 50%; CPK rose 7-fold and Pi 1.5-fold; pHi was not modified. During reperfusion, all parameters recovered in part, with exception of Pi. PBN developed a marked protective activity on all tested parameters, which gained a nearly normal value. The results of the present investigations show that the lipophilic spin trap PBN partly protects the heart from the ischemia/reperfusion injury, thus confirming that free radicals play a causal role in this pathology; the continuous loading of the tissue with the drug can be an important factor for obtaining the protective effect.


Assuntos
Traumatismo por Reperfusão Miocárdica/prevenção & controle , Óxidos de Nitrogênio/farmacologia , Marcadores de Spin , Trifosfato de Adenosina/metabolismo , Animais , Creatina Quinase/metabolismo , Óxidos N-Cíclicos , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Masculino , Miocárdio/metabolismo , Fosfatos/metabolismo , Fosfocreatina/efeitos dos fármacos , Fosfocreatina/metabolismo , Ratos , Ratos Endogâmicos
19.
Free Radic Res Commun ; 14(1): 41-5, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-2022345

RESUMO

Adriamycin (ADR) is known to exert a severe negative inotropic effect on isolated myocardial preparations; a role for free radical generation has been hypothesized. Spin-trapping of free radicals has been extensively exploited in ESR studies, both in cell-free systems and in intact tissues. The interaction between spin-traps and free radicals should in principle stop the reaction cascade leading to cellular damage. Based on this hypothesis, the possible cardioprotective action of three spin-trapping agents, 5,5-dimethyl-l-pyrroline-N-oxide (DMPO), N-tert-butyl-alpha-phenylnitrone (PBN) and alpha-(4-pyridyl 1-oxide) N-tert-butylnitrone (POBN), was tested on isolated rat atria incubated in the presence of ADR; maximal non-cardiotoxic concentrations were used (50, 10 and 50 mM respectively) in order to achieve a maximal spin-trapping effect. A varying degree of protection was observed with the three compounds, directly correlated to their hydrophobicity, as assessed by chloroform/water partition coefficients. It is proposed that ADR-induced free radical generation is responsible for the acute cardiotoxic effects of the drug; this seems to be a site-specific mechanism restricted to one or more hydrophobic cellular compartment/s, since only lipophilic spin-trapping agents are able to prevent the development of the negative inotropic effect of ADR.


Assuntos
Cardiomiopatias/induzido quimicamente , Doxorrubicina/toxicidade , Contração Miocárdica/efeitos dos fármacos , Marcadores de Spin , Animais , Cardiomiopatias/fisiopatologia , Óxidos N-Cíclicos/farmacologia , Depressão Química , Doxorrubicina/farmacologia , Feminino , Radicais Livres , Cinética , Óxidos de Nitrogênio/farmacologia , Piridinas , Ratos , Ratos Endogâmicos
20.
Cancer Lett ; 50(1): 79-85, 1990 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-2353985

RESUMO

The effects of angiotensin II (AII) on the antitumor activity and cardiotoxicity of doxorubicin (DXR) were tested in rats bearing Walker 256/A carcinoma. The animals received 2, 4 or 6 mg/kg of DXR as a bolus i.v. injection, with or without a concurrent i.v. infusion of 2 micrograms/kg/min of AII, starting 1 h prior to DXR administration for a total of 6 h. Neither the antitumor activity, nor the myocardial toxicity of DXR, as assessed by ECG evaluation (Q alpha T duration), were affected by AII at the tested dose. 100% of the animals receiving 6 mg/kg of DXR with or without AII were cured from the tumor, but subsequently some of them developed toxic signs and eventually died within the 12th week after treatment. Rats receiving DXR + AII showed a higher long-term survival than those receiving DXR alone; therefore, a possible interference with other DXR-induced side effects, such as nephrotoxicity, is hypothesized.


Assuntos
Angiotensina II/farmacologia , Doxorrubicina/toxicidade , Coração/efeitos dos fármacos , Neoplasias Experimentais/tratamento farmacológico , Animais , Peso Corporal/efeitos dos fármacos , Doxorrubicina/uso terapêutico , Feminino , Rim/efeitos dos fármacos , Ratos , Ratos Endogâmicos
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