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2.
J Nutr Health Aging ; 23(8): 739-745, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31560032

RESUMO

OBJECTIVES: Autophagy is a physiological and highly regulated mechanism, crucial for cell homeostasis maintenance. Its impairment seems to be involved in the onset of several diseases, including muscular dystrophies, myopathies and sarcopenia. According to few papers, chemotherapeutic drug treatment is able to trigger side effects on skeletal muscle tissue and, among these, a defective autophagic activation, which leads to the persistence of abnormal organelles within cells and, finally, to myofiber degeneration. The aim of this work is to find a strategy, based on diet modulation, to prevent etoposide-induced damage, in a model of in vitro skeletal muscle cells. METHODS: Glutamine supplementation and nutrient deprivation have been chosen as pre-treatments to counteract etoposide effect, a chemotherapeutic drug known to induce oxidative stress and cell death. Cell response has been evaluated by means of morpho-functional, cytofluorimetric and molecular analyses. RESULTS: Etoposide treated cells, if compared to control, showed dysfunctional mitochondria presence, ER stress and lysosomal compartment damage, confirmed by molecular investigations. CONCLUSIONS: Interestingly, both dietary approaches were able to rescue myofiber from etoposide-induced damage. Glutamine supplementation, in particular, seemed to be a good strategy to preserve cell ultrastructure and functionality, by preventing the autophagic impairment and partially restoring the normal lysosomal activity, thus maintaining skeletal muscle homeostasis.


Assuntos
Autofagia/fisiologia , Dieta/métodos , Músculo Esquelético/fisiopatologia , Humanos
3.
Leukemia ; 32(1): 1-10, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28951560

RESUMO

CK2 is a ubiquitously expressed, constitutively active Ser/Thr protein kinase, which is considered the most pleiotropic protein kinase in the human kinome. Such a pleiotropy explains the involvement of CK2 in many cellular events. However, its predominant roles are stimulation of cell growth and prevention of apoptosis. High levels of CK2 messenger RNA and protein are associated with CK2 pathological functions in human cancers. Over the last decade, basic and translational studies have provided evidence of CK2 as a pivotal molecule driving the growth of different blood malignancies. CK2 overexpression has been demonstrated in nearly all the types of hematological cancers, including acute and chronic leukemias, where CK2 is a key regulator of signaling networks critical for cell proliferation, survival and drug resistance. The findings that emerged from these studies suggest that CK2 could be a valuable therapeutic target in leukemias and supported the initiation of clinical trials using CK2 antagonists. In this review, we summarize the recent advances on the understanding of the signaling pathways involved in CK2 inhibition-mediated effects with a particular emphasis on the combinatorial use of CK2 inhibitors as novel therapeutic strategies for treating both acute and chronic leukemia patients.


Assuntos
Caseína Quinase II/metabolismo , Leucemia/tratamento farmacológico , Leucemia/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Humanos , Transdução de Sinais/efeitos dos fármacos
4.
Leukemia ; 30(11): 2142-2151, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27461062

RESUMO

Sphingolipids, such as ceramide, sphingosine and sphingosine 1-phosphate (S1P) are bioactive molecules that have important functions in a variety of cellular processes, which include proliferation, survival, differentiation and cellular responses to stress. Sphingolipids have a major impact on the determination of cell fate by contributing to either cell survival or death. Although ceramide and sphingosine are usually considered to induce cell death, S1P promotes survival of cells. Sphingosine kinases (SPHKs) are the enzymes that catalyze the conversion of sphingosine to S1P. There are two isoforms, SPHK1 and SPHK2, which are encoded by different genes. SPHK1 has recently been implicated in contributing to cell transformation, tumor angiogenesis and metastatic spread, as well as cancer cell multidrug-resistance. More recent findings suggest that SPHK2 also has a role in cancer progression. This review is an overview of our understanding of the role of SPHKs and S1P in hematopoietic malignancies and provides information on the current status of SPHK inhibitors with respect to their therapeutic potential in the treatment of hematological cancers.


Assuntos
Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/enzimologia , Terapia de Alvo Molecular/métodos , Progressão da Doença , Humanos , Lisofosfolipídeos/antagonistas & inibidores , Fosfotransferases (Aceptor do Grupo Álcool)/antagonistas & inibidores , Inibidores de Proteínas Quinases/uso terapêutico , Esfingosina/análogos & derivados , Esfingosina/antagonistas & inibidores
5.
Leukemia ; 28(3): 543-53, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24253024

RESUMO

Constitutively active casein kinase 2 (CK2) signaling is a common feature of T-cell acute lymphoblastic leukemia (T-ALL). CK2 phosphorylates PTEN (phosphatase and tensin homolog) tumor suppressor, resulting in PTEN stabilization and functional inactivation. Downregulation of PTEN activity has an impact on PI3K/Akt/mTOR signaling, which is of fundamental importance for T-ALL cell survival. These observations lend compelling weight to the application of CK2 inhibitors in the therapy of T-ALL. Here, we have analyzed the therapeutic potential of CX-4945-a novel, highly specific, orally available, ATP-competitive inhibitor of CK2α. We show that CX-4945 treatment induced apoptosis in T-ALL cell lines and patient T lymphoblasts. CX-4945 downregulated PI3K/Akt/mTOR signaling in leukemic cells. Notably, CX-4945 affected the unfolded protein response (UPR), as demonstrated by a significant decrease in the levels of the main UPR regulator GRP78/BIP, and led to apoptosis via upregulation of the ER stress/UPR cell death mediators IRE1α and CHOP. In vivo administration of CX-4945 to a subcutaneous xenotransplant model of human T-ALL significantly delayed tumor growth. Our findings indicate that modulation of the ER stress/UPR signaling through CK2 inhibition could be exploited for inducing apoptosis in T-ALL cells and that CX-4945 may be an efficient treatment for those T-ALLs displaying upregulation of CK2α/PI3K/Akt/mTOR signaling.


Assuntos
Antineoplásicos/uso terapêutico , Caseína Quinase II/antagonistas & inibidores , Naftiridinas/uso terapêutico , Proteínas de Neoplasias/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Transdução de Sinais , Resposta a Proteínas não Dobradas , Animais , Divisão Celular , Chaperona BiP do Retículo Endoplasmático , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Proteínas de Neoplasias/química , Fenazinas , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia
6.
Leukemia ; 28(6): 1196-206, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24310736

RESUMO

Constitutively active phosphoinositide 3-kinase (PI3K) signaling is a common feature of T-cell acute lymphoblastic leukemia (T-ALL), where it upregulates cell proliferation, survival and drug resistance. These observations lend compelling weight to the application of PI3K inhibitors in the therapy of T-ALL. Here, we have analyzed the therapeutic potential of the pan-PI3K inhibitor NVP-BKM120 (BKM120), an orally bioavailable 2,6-dimorpholino pyrimidine derivative, which has entered clinical trials for solid tumors, on both T-ALL cell lines and patient samples. BKM120 treatment resulted in G2/M phase cell cycle arrest and apoptosis, being cytotoxic to a panel of T-ALL cell lines and patient T lymphoblasts, and promoting a dose- and time-dependent dephosphorylation of Akt and S6RP. BKM120 maintained its pro-apoptotic activity against Jurkat cells even when cocultured with MS-5 stromal cells, which mimic the bone marrow microenvironment. Remarkably, BKM120 synergized with chemotherapeutic agents currently used for treating T-ALL patients. Moreover, in vivo administration of BKM120 to a subcutaneous xenotransplant model of human T-ALL significantly delayed tumor growth, thus prolonging survival time. Taken together, our findings indicate that BKM120, either alone or in combination with chemotherapeutic drugs, may be an efficient treatment for T-ALLs that have aberrant upregulation of the PI3K signaling pathway.


Assuntos
Aminopiridinas/farmacologia , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Morfolinas/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Animais , Western Blotting , Citometria de Fluxo , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Farm Hosp ; 37(2): 103-10, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23789754

RESUMO

OBJECTIVE: Two clobazam aqueous suspensions for paediatric oral usage (5 mg/ml) were investigated to determinate its physicochemical stability under different storage conditions. METHOD: Formulations were stored at 4 and 25 °C and the clobazam content was determined by High Performance Liquid Chromatography. Each sample was analyzed by triplicate at different time points (0, 7, 14, 28 and 56 days). RESULTS: Liquid suspensions were successfully formulated from pure drug and commercially available tablets. In both cases, samples showed suitable physical stability. Clobazam was chemically stable in aqueous suspension during the 56 days of the study at the two storage temperatures. CONCLUSIONS: All the tried oral liquid formulations can be conserved at 4 and 25 °C at least 56-day period.


Objetivo: Dos suspensiones orales acuosas de clobazam para uso pediátrico (5 mg/ml) fueron evaluadas para determinar su estabilidad fisicoquimica bajo diferentes condiciones de almacenamiento. Métodos: Las formulaciones fueron conservadas a 4 y 25 °C y el contenido de clobazam fue determinado mediante Cromatografía Líquida de Alta Performance. Cada una de las muestras fue analizada por triplicado a diferentes tiempos (0, 7, 14, 28 y 56 días). Resultados: Las suspensiones fueron formuladas satisfactoriamente a partir del principio activo puro y de comprimidos disponibles comercialmente. En ambos casos, las muestras presentaron una adecuada estabilidad física. El clobazam fue químicamente estable en las suspensiones acuosas durante los 56 días de duración del estudio a las dos temperaturas elegidas para su conservación. Conclusiones: Todas las formulaciones orales líquidas formuladas y evaluadas en este estudio pueden ser conservadas a 4 y 25 °C por al menos 56 días.


Assuntos
Anticonvulsivantes , Benzodiazepinas , Clobazam , Composição de Medicamentos , Estabilidade de Medicamentos , Pediatria , Suspensões , Comprimidos
8.
Farm. hosp ; 37(2): 103-110, mar.-abr. 2013. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-115661

RESUMO

Objective: Two clobazam aqueous suspensions for paediatric oral usage (5 mg/ml) were investigated to determinate its physicochemical stability under different storage conditions. Method: Formulations were stored at 4 and 25 oC and the clobazam content was determined by High Performance Liquid Chromatography. Each sample was analyzed by triplicate at different time points (0, 7, 14, 28 and 56 days). Results: Liquid suspensions were successfully formulated from pure drug and commercially available tablets. In both cases, samples showed suitable physical stability. Clobazam was chemically stable in aqueous suspension during the 56 days of the study at the two storage temperatures. Conclusions: All the tried oral liquid formulations can be conserved at 4 and 25 oC at least 56-day period (AU)


Objetivo: Dos suspensiones orales acuosas de clobazam para uso pediátrico (5 mg/ml) fueron evaluadas para determinar su estabilidad fisicoquimica bajo diferentes condiciones de almacenamiento. Métodos: Las formulaciones fueron conservadas a 4 y 25 oC y el contenido de clobazam fue determinado mediante Cromatografía Líquida de Alta Performance. Cada una de las muestras fue analizada por triplicado a diferentes tiempos (0, 7, 14, 28 y 56 días). Resultados: Las suspensiones fueron formuladas satisfactoriamente a partir del principio activo puro y de comprimidos disponibles comercialmente. En ambos casos, las muestras presentaron una adecuada estabilidad física. El clobazam fue químicamente estable en las suspensiones acuosas durante los 56 días de duración del estudio a las dos temperaturas elegidas para su conservación. Conclusiones: Todas las formulaciones orales líquidas formuladas y evaluadas en este estudio pueden ser conservadas a 4 y 25 oC por al menos 56 días (AU)


Assuntos
Humanos , Masculino , Feminino , Criança , Epilepsia/tratamento farmacológico , Anticonvulsivantes/administração & dosagem , Estabilidade de Medicamentos , Suspensões/análise , Estabilidade de Medicamentos
9.
Artigo em Inglês | MEDLINE | ID: mdl-23215723

RESUMO

The phosphatidylinositol 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR) are two major signaling molecules in the PI3K/Akt/mTOR signal transduction cascade. This pathway is a key regulator of a wide range of physiological cell processes which include proliferation, differentiation, survival, metabolism, exocytosis, motility, and autophagy. However, aberrantly upregulated PI3K/Akt/mTOR signaling characterizes many types of cancers where it negatively influences response to therapeutic treatments. Therefore, targeting PI3K/Akt/mTOR signaling with small molecule inhibitors could improve cancer patient outcome. The PI3K/Akt/mTOR signaling network is activated in acute leukemias of both myelogenous and lymphoid lineage, where it correlates with poor prognosis and enhanced drug-resistance. The catalytic sites of PI3K and mTOR share a high degree of sequence homology. This feature has allowed the synthesis of ATP-competitive compounds that targeted the catalytic site of both PI3K and mTOR (e.g. PI-103, NVP-BEZ235). In preclinical settings, dual PI3K/mTOR inhibitors displayed a much stronger cytotoxicity against leukemic cells than either PI3K inhibitors or allosteric mTOR inhibitors, such as rapamycin and its derivatives (rapalogs). At variance with rapamycin/rapalogs, dual PI3K/mTOR inhibitors targeted both mTOR complex 1 and mTOR complex 2, and inhibited the rapamycin-resistant phosphorylation of eukaryotic initiation factor 4E-binding protein 1, resulting in a marked inhibition of oncogenetic protein translation in leukemic cells. Hence, they strongly reduced the proliferation rate and induced an important apoptotic response. Here, we reviewed the evidence documenting that dual PI3K/mTOR inhibitors represent a promising option for future targeted therapies of leukemic patients.

10.
Farm. hosp ; 36(6): 492-497, nov.-dic. 2012. graf, tab
Artigo em Inglês | IBECS | ID: ibc-135942

RESUMO

Objective: To study the stability of Coenzyme Q10 (CoQ10), used as therapeutic agent in treatment of cardiovascular and mitochondrial diseases, in three liquid formulations: two soybean oil solutions (50 mg/ml), one of them with the addition of vitamin E and an O/W emulsion (20 mg/ml) for pediatric use. Furthermore, optimize and validate a stabilityindicating HPLC method for the analysis of CoQ10 in the studied formulations. Method: All samples were stored at 25°C. CoQ10 content of each formulation was analyzed in duplicate using fast microbore high performance liquid chromatography (Micro HPLC) at 0, 3, 6, 15, 30, 60 and 110 days. Results: All formulations stayed stable at 25°C during the 110 days of the study. However, the oil solutions presented greater content variations through all the study period. Conclusions: The CoQ10 emulsion can be stored for at least 110 days at 25 °C and it has proven to be safer when narrow dose adjustment is required. The proposed analytical method was suitable for the study of stability of different formulations meeting the validation parameters according to international guidelines (AU)


Objetivo: Estudiar la estabilidad de Coenzima Q10 (CoQ10), utilizada como agente terapéutico en el tratamiento de enfermedades cardiovasculares y mitocondriales en 2 soluciones con aceite de soja como vehículo (50 mg/ml), una de ellas con el agregado de vitamina E y una emulsión O/W (20 mg/ml) para uso pediátrico. Asimismo, optimizar y validar un método indicativo de estabilidad por HPLC aplicado al análisis de CoQ10 en las respectivas formulaciones estudiadas. Método: Todas las muestras fueron almacenadas a temperatura ambiente (25 °C) y su contenido fue analizado utilizando Micro HPLC. Cada muestra fue analizada por duplicado a los 0, 3, 6, 15, 30, 60 y 110 días. Resultados: La coenzima Q10 se mantuvo estable en las formulaciones durante los 110 días a una temperatura de 25°C. Sin embargo, se detectó una mayor variación en las concentraciones obtenidas para las dos soluciones en aceite de soja. Conclusiones: La emulsión O/W de CoQ10 puede ser almacenada por al menos 110 días a 25°C y demostró ser más segura cuando se requiere ajustar la dosis. El método analítico propuesto fue adecuado para realizar el estudio de estabilidad de las distintas formulaciones cumpliendo con los parámetros de validación acorde a las guías internacionales (AU)


Assuntos
Humanos , Criança , Vitaminas/análise , Ubiquinona/análogos & derivados , Ubiquinona/análise , Óleo de Soja , Emulsões , Armazenamento de Medicamentos , Administração Oral , Química Farmacêutica , Cromatografia Líquida de Alta Pressão , Formas de Dosagem , Estabilidade de Medicamentos
11.
Farm Hosp ; 36(6): 492-7, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23461442

RESUMO

OBJECTIVE, To study the stability of Coenzyme Q10 (CoQ10), used as therapeutic agent in treatment of cardiovascular and mitochondrial diseases, in three liquid formulations: two soybean oil solutions (50 mg/ml), one of them with the addition of vitamin E and an O/W emulsion (20 mg/ml) for pediatric use. Furthermore, optimize and validate a stabilityindicating HPLC method for the analysis of CoQ10 in the studied formulations. METHOD, All samples were stored at 25°C. CoQ10 content of each formulation was analyzed in duplicate using fast microbore high performance liquid chromatography (Micro HPLC) at 0, 3, 6, 15, 30, 60 and 110 days. RESULTS, All formulations stayed stable at 25°C during the 110 days of the study. However, the oil solutions presented greater content variations through all the study period. CONCLUSIONS, The CoQ10 emulsion can be stored for at least 110 days at 25 °C and it has proven to be safer when narrow dose adjustment is required. The proposed analytical method was suitable for the study of stability of different formulations meeting the validation parameters according to international guidelines.


Assuntos
Ubiquinona/análogos & derivados , Vitaminas/análise , Administração Oral , Química Farmacêutica , Criança , Cromatografia Líquida de Alta Pressão , Formas de Dosagem , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Emulsões , Humanos , Óleo de Soja , Ubiquinona/análise
12.
Farm. hosp ; 34(6): 293-297, nov.-dic. 2010. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-107083

RESUMO

Objective Two carvedilol aqueous solutions and one carvedilol aqueous suspension for paediatric oral use (1mg/ml) were studied to determine their stability. Method All samples were stored at 4, 25 and 40°C. Carvedilol content of each of the three formulations was tested using high performance liquid chromatography (HPLC). Each sample was analysed in triplicate at 0, 3, 7, 14, 28 and 56 days. Results Carvedilol stayed stable in the acidic aqueous solution at the three different temperatures during the 56 days of the study. In the alkaline solution, carvedilol was stable during 56 days at 25°C, but only 28 days at 4 and 40°C. In the aqueous suspension, carvedilol was stable during 56 days at 4 and 25°C, but only 28 days at 40°C.ConclusionsAll the formulations that were tested can be stored at 25°C for at least 56 days(AU)


Objetivo Se estudió la estabilidad de carvedilol (1mg/ml) en 2 soluciones acuosas y una suspensión acuosa para uso pediátrico. Método Las formulaciones fueron almacenadas a 4, 25 y 40°C. El contenido de carvedilol de cada una de las 3 formulaciones fue analizado por cromatografía líquida de alta eficacia (HPLC). Cada muestra fue analizada por triplicado a tiempos 0, 3, 7, 14, 28 y 56 días. Resultados Carvedilol se mantuvo estable en la solución acuosa de pH ácido durante los 56 días del ensayo a las 3 temperaturas estudiadas. En la solución alcalina fue estable 56 días a 25°C, pero sólo 28 días a 4 y 40°C. En la suspensión acuosa carvedilol fue estable 56 días a 4 y 25°C, y sólo 28 días a 40°C.ConclusionesTodas las formulaciones ensayadas pueden ser conservadas a 25°C al menos por un período de 56 días (AU)


Assuntos
Humanos , Criança , Carbazóis/farmacologia , Propanolaminas/farmacologia , Estabilidade de Medicamentos , Soluções Farmacêuticas , Propanolaminas/administração & dosagem , Suspensões
13.
Farm Hosp ; 34(6): 293-7, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20418137

RESUMO

OBJECTIVE: Two carvedilol aqueous solutions and one carvedilol aqueous suspension for paediatric oral use (1mg/ml) were studied to determine their stability. METHOD: All samples were stored at 4, 25 and 40°C. Carvedilol content of each of the three formulations was tested using high performance liquid chromatography (HPLC). Each sample was analysed in triplicate at 0, 3, 7, 14, 28 and 56 days. RESULTS: Carvedilol stayed stable in the acidic aqueous solution at the three different temperatures during the 56 days of the study. In the alkaline solution, carvedilol was stable during 56 days at 25°C, but only 28 days at 4 and 40°C. In the aqueous suspension, carvedilol was stable during 56 days at 4 and 25°C, but only 28 days at 40°C. CONCLUSIONS: All the formulations that were tested can be stored at 25°C for at least 56 days.


Assuntos
Carbazóis/farmacologia , Propanolaminas/farmacologia , Administração Oral , Carbazóis/administração & dosagem , Carvedilol , Criança , Estabilidade de Medicamentos , Humanos , Soluções Farmacêuticas , Propanolaminas/administração & dosagem , Suspensões
14.
Med. infant ; 15(3): 233-239, sept. 2008. tab
Artigo em Espanhol | LILACS, BINACIS, UNISALUD | ID: lil-544699

RESUMO

El estudio del crecimiento a largo plazo de niños con raquitismo hipofosfatémico familiar, demostró que 18 de los 30 pacientes estudiados no crecían adecuadamente, y que a su vez este pobre crecimiento estaba asociado a una falta de cumplimiento de la ingesta de fósforo indicada por el médico tratante, medicación que forma parte esencial de la terapia. Entre las principales causas identificadas de falta de cumplimiento se encontró la incapacidad de muchas farmacias del país de preparar la solución de sales de fósforo, las dificultades de transporte y conservación de dichas sales, la inestabilidad de la solución, la falta de recursos de los pacientes sin cobertura, la dificultad de las obras sociales en financiar las sales en los pacientes con cobertura. Luego de reuniones mantenidas entre miembros de un equipo multidiciplinarios formado ad hoc, la farmacia del hospital logró preparar una cápsula con sales de fósforo para ser disuelta en agua en el hogar, se estableció un circuito de entrega gratuita del medicamento al paciente aprobado por las autoridades del Hospital, y un sistema de cobro a los organismos pagadores en los casos que correspondiera. La autorización de la Dirección fue tomada en base a la necesidad de mejorar la calidad de atención en estos pacientes, al relativo bajo costo del medicamento (1180 pesos por pacientes por año), y el escaso número de pacientes bajo tratamiento. La vigilancia del crecimiento en pacientes crónicos probó en este caso ser una herramienta confiable y sencilla para detectar un problema generalizado en el tratamiento de una enfermedad y mejorar la calidad de la atención.


Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Criança , Adolescente , Calcitriol/uso terapêutico , Comercialização de Medicamentos , Crescimento e Desenvolvimento , Fósforo/uso terapêutico , Hipofosfatemia Familiar , Insuficiência de Crescimento/prevenção & controle
15.
SAR QSAR Environ Res ; 17(5): 451-71, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17050186

RESUMO

Recent literature has demonstrated the applicability of genetic programming to induction of decision trees for modelling toxicity endpoints. Compared with other decision tree induction techniques that are based upon recursive partitioning employing greedy searches to choose the best splitting attribute and value at each node that will necessarily miss regions of the search space, the genetic programming based approach can overcome the problem. However, the method still requires the discretization of the often continuous-valued toxicity endpoints prior to the tree induction. A novel extension of this method, YAdapt, is introduced in this work which models the original continuous endpoint by adaptively finding suitable ranges to describe the endpoints during the tree induction process, removing the need for discretization prior to tree induction and allowing the ordinal nature of the endpoint to be taken into account in the models built.


Assuntos
Árvores de Decisões , Modelos Teóricos , Relação Quantitativa Estrutura-Atividade , Software , Toxicologia/métodos , Determinação de Ponto Final/métodos
16.
SAR QSAR Environ Res ; 17(1): 53-73, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16513552

RESUMO

The principle of using a singe model to predict the toxicity of mixtures of chemicals based on the characterisation of the degrees of similarity and dissimilarity of the constituent chemicals using descriptors has been demonstrated in a previous work. The current study introduces a feature extraction technique, independent component analysis, to the method to remove the correlations and dependencies between descriptors and reduce the dimension prior to similarity and dissimilarity calculations. In addition, a goal attainment multi-objective optimisation technique is used for the determination of the fuzzy membership function parameters. For three mixtures, which include a new mixture and two previously studied mixtures that all inhibit reproduction (via different mechanisms of action) in green freshwater algae scenedesmus vacuolatus, the approach showed better or equivalent prediction performance than either concentration addition or independent action models. Unlike QSARs for pure compounds that require large collections of data, the new approach for mixtures only requires one mixture at a particular composition to determine the necessary fuzzy membership function parameter values. These values can then be used to predict the toxicity of the mixture at any other compositions. This could potentially lead to a reduction in the frequency of bioassay tests. Use of the fuzzy membership functions and parameter values obtained for one mixture when used to predict the toxicity of a completely different mixture is also tested and it is found that the approach also gives prediction results with good accuracy.


Assuntos
Lógica Fuzzy , Relação Quantitativa Estrutura-Atividade , Testes de Toxicidade/métodos , Clorófitas/efeitos dos fármacos
17.
Biochem Biophys Res Commun ; 314(1): 138-42, 2004 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-14715257

RESUMO

Growing evidence supports the critical role of lipid peroxidation products in the control of cell proliferation. In previous studies we demonstrated the efficient restriction of the proliferation rate in several cell lines resulting from the in vitro treatment with endogenous lipid polar components of cell membranes. Among these, 9-hydroxystearic acid (9-HSA), a primary intermediate of lipid peroxidation, induced a significant arrest in G0/G1 in HT29 colon cancer cells. In response to 9-HSA treatment of HT29 we observed cell growth arrest and increase in p21(WAF1) expression both at the transcriptional and the translational levels. Growth of p21(WAF1)-deleted HCT116 human colon carcinoma cells was not inhibited by 9-HSA. We present evidence that p21(WAF1) is required for 9-HSA mediated growth arrest in human colon carcinoma cells.


Assuntos
Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Ciclinas/metabolismo , Ácidos Esteáricos/metabolismo , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Linhagem Celular Tumoral/patologia , Inibidor de Quinase Dependente de Ciclina p21 , Humanos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Ácidos Esteáricos/farmacologia , Regulação para Cima/efeitos dos fármacos
18.
Med. infant ; 4(4): 243-245, dic. 1997. tab
Artigo em Espanhol | LILACS | ID: lil-526972

RESUMO

El servicio de Farmacia tiene la esponsabilidad de satisfacer los requerimientos de los pacientes que por su edad o patología no pueden ingerir medicamentos con formas farmacéuticas sólidas. El objetivo de este trabajo fue realizar una suspensión extemporánea oral de Zidovudina. La farmacia Oncológica entre medicamentos a pacientes HIV ambulatorios cada 15 días, para garantir el cumplimiento terpéutico; por tal motivo, se tomó como período arbitrario 30 días, para el estudio de la suspensión, se partió de cápsulas originales de Zidovudina y se midió la estabilidad de la suspensión oral de 10 mg/ml, a treinta días y a 4º C, 25º C y 37º C de temperatura, por técnica cromatográfica con HPLC. zidovudina suspensión oral 10 mg/ml, resultó estable a 4º C, 25º C y 37º C de temperatura, durante 30 días.


Assuntos
Estabilidade de Medicamentos , Suspensões , Zidovudina
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