RESUMO
Poly(lactic-acid) (PLA) is a biodegradable polymer widely used as a packaging material. Its monomer, lactic acid, and its derivatives have been used in the food, cosmetic, and chemical industries. The accumulation of PLA residues leads to the development of green degrading methodologies, such as enzymatic degradation. This work evaluates the potential use of three cutinolytic enzymes codified in the Aspergillus nidulans genome to achieve this goal. The results are compared with those obtained with proteinase K from Tritirachium album, which has been reported as a PLA-hydrolyzing enzyme. The results show that all three cutinases act on the polymer, but ANCUT 1 releases the highest amount of lactic acid (25.86 mM). Different reaction conditions assayed later led to double the released lactic acid. A decrease in weight (45.96%) was also observed. The enzyme showed activity both on poly L lactic acid and on poly D lactic acid. Therefore, this cutinase offers the potential to rapidly degrade these package residues, and preliminary data show that this is feasible.
RESUMO
INTRODUCTION: Radiation resistance is a major cause of death in cancer patients. Cancer cells react during radiotherapy by re-programming specific cell functions that may confer resistance to radiation. The understanding of this complex process is hindered due to the lack of appropriate study models. We describe an experimental development of a radioresistant isogenic cancer cell line, and its molecular characterization. MATERIALS AND METHODS: A431-cultured cells were irradiated for 7 month until 85 Gy. Then, a selected single cell was left to grow as stable A431-R cell line. Clonogenic assay was used to determine cell survival, the α and ß parameters of the LQ model, and the mean inactivation dose. The DNA repair ability of cells was evaluated by pulsed-field electrophoresis method. Differential effect of fractionated radiation was ultimately tested in xenografts. Furthermore, we used a wound healing assay, Western blot for EGFR, AKT and ERK1/2 and ELISA test for vascular endothelial growth factor (VEGF) secretion. Finally we explored CD44 marker and cell cycle distribution. RESULTS: The established A431-R cell line showed radiation resistance in clonogenic assays, repair of radiation-induced DNA fragmentation and xenografted tumours. The radiation resistance was associated with in vitro higher cell growth and migration, increased levels of former oncoproteins, and secretion of VEGF. CONCLUSIONS: In this model, the emergence of radiation resistance was associated with the acquisition of biological traits that support more aggressive behaviour of cancer cells. We have generated a model that will be useful for mechanistic studies and development of rational treatments against radiation resistance in cancer.
Assuntos
Carcinoma de Células Escamosas/patologia , Tolerância a Radiação , Animais , Apoptose , Western Blotting , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/radioterapia , Ciclo Celular , Movimento Celular , Proliferação de Células , Relação Dose-Resposta à Radiação , Feminino , Citometria de Fluxo , Raios gama , Humanos , Receptores de Hialuronatos/metabolismo , Camundongos , Camundongos Nus , Fenótipo , Células Tumorais Cultivadas , Fator A de Crescimento do Endotélio Vascular/metabolismo , Cicatrização , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
INTRODUCTION: The aim of this study is to determine the interobserver variability (IV) between radiation oncologists (RO) in target volume delineation for postoperative gastric cancer (GC) radiotherapy planning. MATERIALS AND METHODS: Four physicians were asked to delimitate clinical target volume (CTV) on the same 3D CT images in 9 postoperative radiochemotherapy GC patients. Instructions were given to include tumour bed, remaining stomach, anastomosis, duodenal loop and local lymph nodes. The principal variable was spatial volume discrepancy between the main observer (called "A") and other observers (all called "B"), which were compared using the mathematical formula Aâ£B/Aâ¢B, applied to the 3D CT images using Boolean operators. Analysis of variance with two random effects (observers and patients) was performed. RESULTS: Mean volumes were 1410 cm(3) for OBA, 1231 cm(3) for OB2, 734.6 cm(3) for OB3 and 1350 cm(3) for OB4. Discrepancies were 519.9±431.6 cm(3) for OB2, 652.1±294.36 cm(3) for OB3 and 225.90±237.07 cm(3) for OB4. Standard deviation ascribed to patients as random effect was 898.6 cm(3) and that ascribed to observers was 198.10 cm(3), considered as a statistically significant difference. CONCLUSIONS: A significant IV in target delineation that can be attributed to many factors depends more on patients' characteristics than RO delineating decisions.
Assuntos
Quimiorradioterapia , Variações Dependentes do Observador , Padrões de Prática Médica , Radioterapia (Especialidade) , Planejamento da Radioterapia Assistida por Computador , Neoplasias Gástricas/diagnóstico por imagem , Neoplasias Gástricas/terapia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Feminino , Fluoruracila/administração & dosagem , Seguimentos , Humanos , Leucovorina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/diagnóstico por imagem , Recidiva Local de Neoplasia/terapia , Projetos Piloto , Prognóstico , Estudos Prospectivos , Tomografia Computadorizada por Raios XRESUMO
The goal of this paper is to expose the clinical results and review of the literature of the treatment of spinal metastases with Stereotactic Body Radiation Therapy (SBRT) presenting one case. A spinal metastases from rectal cancer treated with a single dose of 18Gy is presented. The following physics aspects are exposed: Treatment volume, tumor volume marginal doses and maximum doses in organs at risk. Clinical and radiographic follow up is presented. Local control and pain relief after one year of follow up was excellent. In properly selected patients, the treatment of limited metastatic disease with SBRT appears to be feasible and safe.
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Radiocirurgia , Neoplasias Retais/patologia , Neoplasias da Coluna Vertebral/secundário , Neoplasias da Coluna Vertebral/cirurgia , Terapia Combinada , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Retais/terapia , Resultado do TratamentoRESUMO
The esterification of phenylpropanoid and hydrophenylpropanoid acids, catalyzed by candida antarctica lipase B (CAL-B), with several alcohols has demonstrated that the substitution pattern on the aromatic ring has a very significant influence on the reactivity of the carboxyl group due, mainly, to electronic effects, when compared to the unsaturated acids with the hydrogenated acids. It is also clear that in the saturated acids there still remain some unclear effects related to the aromatic substituents.
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Esterificação , Fenilpropionatos/metabolismo , Lipase/metabolismo , Catálise , Cromatografia Líquida de Alta Pressão , Candida/enzimologia , Enzimas Imobilizadas/metabolismo , Enzimas Imobilizadas/química , Fenilpropionatos/química , Lipase/química , SolventesRESUMO
We used Daphnia magna bioassays to determine the LC(50) and the effects on the heart of the cardioactive drugs ouabain, verapamil, metaproterenol and metoprolol. Distinctions were made between the pharmacological and toxicological effects of these drugs and the adequacy of physicochemical characteristics of its habitat (reconstituted water). Video microscopy and digital image processing were used to study the pharmacological effects on the heart. D. magna exhibited the expected sensitivity to the reference toxicant sodium dodecyl sulfate with a LC(50) of 15.6+/-4.5 mg/l. All drugs were toxic with 48 h-LC(50) of 2.03 mg/l ouabain, 7.04 mg/l verapamil, 32.45 mg/l metaproterenol and 76.21 mg/l metoprolol. Ouabain was the most toxic and caused a positive concentration-dependent inotropic effect. Verapamil caused positive chronotropic and inotropic effects, while metaproterenol showed positive concentration-dependent chronotropic effects at high concentrations (10(-3) and 10(-4) M). Metoprolol induced a positive chronotropic effect at low concentrations (10(-8), 10(-7), 10(-6) M) and a negative chronotropic effect at high concentration (10(-4) M). Ouabain, metaproterenol and metoprolol in D. magna caused similar effects to those produced in mammals. In contrast, verapamil caused opposite effects. The results suggest the presence of Na(+), K(+)-ATPase receptors to verapamil and of non-specific adrenergic receptors in heart of D. magna.
Assuntos
Cardiotônicos/toxicidade , Daphnia , Coração/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Coração/fisiopatologia , Frequência Cardíaca/efeitos dos fármacos , Dose Letal Mediana , Metaproterenol/toxicidade , Metoprolol/toxicidade , Ouabaína/toxicidade , Dodecilsulfato de Sódio/farmacologia , Verapamil/toxicidadeRESUMO
Bovinos, principalmente, e eqüinos foram utilizados como bioindicadores para se avaliar a poluição ambiental ocasionada poruma indústria metalífera, numa localidade rural no estado do Paraná Os animais eram criados nas circunvizinhanças de umafábrica produtora de grande quantidade de baterias para veículos automotores. Análises da água de beber, solo, capim e salmineral foram efetuadas para se investigar as fontes tóxicas aos animais. Um total de 25 animais foram monitorados atravésdos exames clínicos e análises hematológicas, para se investigar a presença de chumbo inorgânico, considerado comoelemento metálico prioritário e/ou essencial na manufatura de baterias automotivas. Os resultados demonstraram ter havido. comprometimento da saúde dos animais pela poluição ambiental nos efluentes industriais líquidos e gasosos incorporadosàs pastagens e fontes de água.
RESUMO
Bovinos, principalmente, e eqüinos foram utilizados como bioindicadores para se avaliar a poluição ambiental ocasionada poruma indústria metalífera, numa localidade rural no estado do Paraná Os animais eram criados nas circunvizinhanças de umafábrica produtora de grande quantidade de baterias para veículos automotores. Análises da água de beber, solo, capim e salmineral foram efetuadas para se investigar as fontes tóxicas aos animais. Um total de 25 animais foram monitorados atravésdos exames clínicos e análises hematológicas, para se investigar a presença de chumbo inorgânico, considerado comoelemento metálico prioritário e/ou essencial na manufatura de baterias automotivas. Os resultados demonstraram ter havido. comprometimento da saúde dos animais pela poluição ambiental nos efluentes industriais líquidos e gasosos incorporadosàs pastagens e fontes de água.