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1.
Environ Monit Assess ; 191(12): 708, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31677112

RESUMO

This work focuses on the Thermophilic Aerobic Membrane Reactor (TAMR) process. The research was carried out on a full-scale facility where, all along a 12-year period, daily monitoring and process audit tests were conducted for the process analysis and optimization. The plant treated -light and high-strength aqueous wastes and two different configurations were adopted: (1) thermophilic biological reactor + ultrafiltration (TAMR) and (2) TAMR + nanofiltration (TAMR + NF). In the latter case, the average chemical oxygen demand removal yield was equal to 89% and an effective denitrification (nitrogen oxides removal equal to 96%) was achieved by reducing the dissolved oxygen concentration in the bioreactor. Low specific sludge production was observed. Poor sludge settling properties were measured by a lab-scale settling test; respirometric tests (nitrogen uptake rate and ammonia uptake rate) showed the presence of denitrification and the inhibition of nitrification. Hydrodynamic tests revealed the presence of a significant dead space, thus showing room for improving the overall process performance. Finally, the rheological properties of the sludge were measured as a function of the biomass concentration, pH, temperature, and aeration scheme.


Assuntos
Reatores Biológicos , Ultrafiltração , Eliminação de Resíduos Líquidos , Análise da Demanda Biológica de Oxigênio , Biomassa , Desnitrificação , Monitoramento Ambiental , Nitrificação , Nitrogênio , Esgotos/química , Águas Residuárias/química
2.
Phys Med Biol ; 63(18): 185021, 2018 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-30229740

RESUMO

Evaluation of the radioisotopic purity of technetium-99m (99mTc) produced in GBq amounts by proton bombardment of enriched molibdenum-100 (100Mo) metallic targets at low proton energies (i.e. within 15-20 MeV) is conducted. This energy range was chosen since it is easily achievable by many conventional medical cyclotrons already available in the nuclear medicine departments of hospitals. The main motivation for such a study is in the framework of the research activities at the international level that have been conducted over the last few years to develop alternative production routes for the most widespread radioisotope used in medical imaging. The analysis of technetium isotopes and isomeric states (9xTc) present in the pertechnetate saline Na99mTcO4 solutions, obtained after the extraction/purification procedure, reveals radionuclidic purity levels basically in compliance with the limits recently issued by European Pharmacopoeia 9.3 (2018 Sodium pertechnetate (99mTc) injection 4801-3). Moreover, the impact of 9xTc contaminant nuclides on the final image quality is thoroughly evaluated, analyzing the emitted high-energy gamma rays and their influence on the image quality. The spatial resolution of images from cyclotron-produced 99mTc acquired with a mini-gamma camera was determined and compared with that obtained using technetium-99m solutions eluted from standard 99Mo/99mTc generators. The effect of the increased image background contribution due to Compton-scattered higher-energy gamma rays (E γ > 200 keV), which could cause image-contrast deterioration, was also studied. It is concluded that, due to the high radionuclidic purity of cyclotron-produced 99mTc using 100Mo(p,2n)99mTc reaction at a proton beam energy in the range 15.7-19.4 MeV, the resulting image properties are well comparable with those from the generator-eluted 99mTc.


Assuntos
Compostos Radiofarmacêuticos/normas , Tecnécio/normas , Ciclotrons , Isótopos/química , Molibdênio/química , Prótons , Compostos Radiofarmacêuticos/química , Pertecnetato Tc 99m de Sódio/química , Tecnécio/química
3.
Oncogene ; 37(6): 787-797, 2018 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-29059168

RESUMO

In acute myeloid leukemia (AML), internal tandem duplication mutations in the FLT3 tyrosine kinase receptor (FLT3-ITD) account for up to 25% of cases and are associated with a poor outcome. In order to better target this AML subtype, a comprehensive view of how FLT3-ITD impacts AML cell biology is required. Here, we found that FLT3-ITD expression increased basal autophagy in AML cells, and that both pharmacological and genetic inhibition of the receptor reduced autophagy in primary AML samples and cell lines. Conditional expression of shRNAs against key autophagy proteins demonstrated that autophagy is required for AML cell proliferation in vitro and for leukemic cells survival in a mouse model of xenograft. Importantly, autophagy inhibition also overcame FLT3 inhibitor resistance both in vitro and in vivo. The transcription factor ATF4 was identified as an essential actor of FLT3-ITD-induced autophagy. Cellular levels of ATF4 were highly dependent on FLT3-ITD activity, and downregulation of ATF4 inhibited autophagy-dependent AML cell proliferation and improved overall mouse survival similarly to autophagy inhibition. These results suggest that targeting autophagy or ATF4 in patients expressing FLT3 mutations may represent a novel promising and innovative therapeutic strategy for AML.


Assuntos
Fator 4 Ativador da Transcrição/metabolismo , Autofagia , Biomarcadores Tumorais/metabolismo , Resistencia a Medicamentos Antineoplásicos , Leucemia Mieloide Aguda/patologia , Tirosina Quinase 3 Semelhante a fms/metabolismo , Fator 4 Ativador da Transcrição/genética , Animais , Biomarcadores Tumorais/genética , Proliferação de Células , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Mutação , Inibidores de Proteínas Quinases/farmacologia , Sequências de Repetição em Tandem , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto , Tirosina Quinase 3 Semelhante a fms/genética
4.
Oncogene ; 36(26): 3781-3788, 2017 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-28192398

RESUMO

The phosphatase CDC25A is a key regulator of cell cycle progression by dephosphorylating and activating cyclin-CDK complexes. CDC25A is an unstable protein expressed from G1 until mitosis. CDC25A overexpression, which can be caused by stabilization of the protein, accelerates the G1/S and G2/M transitions, leading to genomic instability and promoting tumorigenesis. Thus, controlling CDC25A protein levels by regulating its stability is a critical mechanism for timing cell cycle progression and to maintain genomic integrity. Herein, we show that CDC25A is phosphorylated on Ser40 throughout the cell cycle and that this phosphorylation is established during the progression from G1 to S phase. We demonstrate that CyclinD-CDK4/CDK6 complexes mediate the phosphorylation of CDC25A on Ser40 during G1 and that these complexes directly phosphorylate this residue in vitro. Importantly, we also find that CyclinD1-CDK4 decreases CDC25A stability in a ßTrCP-dependent manner and that Ser40 and Ser88 phosphorylations contribute to this regulation. Thus our results identify cyclinD-CDK4/6 complexes as novel regulators of CDC25A stability during G1 phase, generating a negative feedback loop allowing control of the G1/S transition.


Assuntos
Ciclina D/metabolismo , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Fosfatases cdc25/metabolismo , Pontos de Checagem do Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Ciclina D/genética , Quinase 4 Dependente de Ciclina/genética , Quinase 6 Dependente de Ciclina/genética , Fase G1/fisiologia , Células HEK293 , Humanos , Fosforilação , Estabilidade Proteica , Fase S/fisiologia , Transfecção , Fosfatases cdc25/genética
5.
Ecotoxicol Environ Saf ; 123: 81-8, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26232851

RESUMO

Potential environmental impacts of engineered nanoparticles (ENPs) can be understood taking into consideration phytotoxicity. We reported on the effects of ionic (FeCl3), micro- and nano-sized zerovalent iron (nZVI) about the development of three macrophytes: Lepidium sativum, Sinapis alba and Sorghum saccharatum. Four toxicity indicators (seed germination, seedling elongation, germination index and biomass) were assessed following exposure to each iron concentration interval: 1.29-1570mg/L (FeCl3), 1.71-10.78mg/L (micro-sized iron) and 4.81-33,560mg/L (nano-iron). Exposure effects were also observed by optical and transmission electron microscopy. Results showed that no significant phytotoxicity effects could be detected for both micro- and nano-sized zerovalent irons, including field nanoremediation concentrations. Biostimulation effects such as an increased seedling length and biomass production were detected at the highest exposure concentrations. Ionic iron showed slight toxicity effects only at 1570mg/L and, therefore, no median effect concentrations were determined. By microscopy, ENPs were not found in palisade cells or xylem. Apparently, aggregates of nZVI were found inside S. alba and S. saccharatum, although false positives during sample preparation cannot be excluded. Macroscopically, black spots and coatings were detected on roots of all species especially at the most concentrated treatments.


Assuntos
Cloretos/toxicidade , Compostos Férricos/toxicidade , Lepidium sativum/efeitos dos fármacos , Sinapis/efeitos dos fármacos , Sorghum/efeitos dos fármacos , Fenômenos Químicos , Cloretos/química , Compostos Férricos/química , Germinação/efeitos dos fármacos , Lepidium sativum/crescimento & desenvolvimento , Nanopartículas/química , Nanopartículas/toxicidade , Raízes de Plantas/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Sinapis/crescimento & desenvolvimento , Sorghum/crescimento & desenvolvimento
6.
Metallomics ; 7(2): 267-76, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25561341

RESUMO

The use of platinum, palladium and rhodium (Platinum Group Elements - PGEs) and the possibility of exposure to their ultratrace levels is increasing. In fact, the exponential development of metallic PGE-based nanoparticles (<100 nm in size) opens extraordinary perspectives in the areas of electrocatalysts and catalytic converters, magnetic nanopowders, polymer membranes, cancer therapy, coatings, plastics, nanofibres and textiles. Like other metal-based nanoparticles, exposure to PGEs nanoparticles may result in a release of ultratrace amounts of Pt, Pd, Rh ions in the body whose metabolic fate and toxicity still need to be evaluated. Furthermore, PGEs can act as allergic sensitizers by acting as haptens and inducing both type I and IV allergic reactions. In this work we studied the in vivo metabolic patterns of ultratrace levels of potent allergens and sensitizers PGE halogenated salts. (191)Pt, (103)Pd and (101m)Rh radioisotopes were prepared via cyclotron irradiation and used for radiolabelling Na2(191)PtCl4, Na2(103)PdCl4 and Na2(101m)RhCl6 salts. These anionic chlorocomplexes were intraperitoneally injected into rats (114 ng Pt kg(-1) bodyweight; 24 ng Pd kg(-1) b.w.; 16 ng Rh kg(-1) b.w.). At 16 h post-exposure, PGEs were poorly but significantly retained in all tissues analysed. Kidneys, spleen, adrenal gland, liver, pancreas and small intestine were the organs with the highest Pt, Pd, Rh concentrations. In the blood 30-35% of (103)Pd and (191)Pt and 10% of (101m)Rh were recovered in the plasma, mainly bound to albumin and to a less extent to transferrin. The hepatic and renal intracellular distribution showed the highest recovery of (191)Pt, (103)Pd and (101m)Rh in the nuclear fraction (liver) and in the cytosol (kidney). Chromatographic separation and ultrafiltration experiments on kidney and liver cytosols showed the strong ability of biochemical macromolecules to bind (191)Pt, (103)Pd and (101m)Rh, and being responsible for the retention of the three elements in the body. The link to macromolecules is the basis for the sensitizing capacity of PGEs.


Assuntos
Paládio/metabolismo , Platina/metabolismo , Ródio/metabolismo , Animais , Ânions , Proteínas Sanguíneas/metabolismo , Fracionamento Celular , Cromatografia em Gel , Cromatografia por Troca Iônica , Citosol/metabolismo , Injeções Intraperitoneais , Espaço Intracelular/metabolismo , Rim/metabolismo , Fígado/metabolismo , Masculino , Paládio/sangue , Platina/sangue , Ratos , Ratos Sprague-Dawley , Ródio/sangue , Frações Subcelulares/metabolismo , Distribuição Tecidual , Ultrafiltração
7.
Leukemia ; 28(2): 293-301, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23748345

RESUMO

Phosphorylation by Akt on Ser 280 was reported to induce cytoplasmic retention and inactivation of CHK1 with consequent genetic instability in PTEN-/- cells. In acute myeloid leukemia cells carrying the FLT3-internal tandem duplication (ITD) mutation, we observed high rates of FLT3-ITD-dependent CHK1 Ser 280 phosphorylation. Pharmacological inhibition and RNA interference identified Pim1/2, not Akt, as effectors of this phosphorylation. Pim1 catalyzed Ser 280 phosphorylation in vitro and ectopic expression of Pim1/2-induced CHK1 phosphorylation. Ser 280 phosphorylation did not modify CHK1 localization, but facilitated its cell cycle and resistance functions in leukemic cells. FLT3, PIM or CHK1 inhibitors synergized with DNA-damaging agents to induce apoptosis, allowing cells to bypass the etoposide-induced G2/M arrest. Consistently, etoposide-induced CHK1-dependent phosphorylations of CDC25C on Ser 216 and histone H3 on Thr11 were decreased upon FLT3 inhibition. Accordingly, ectopic expression of CHK1 improved the resistance of FLT3-ITD cells and maintained histone H3 phosphorylation in response to DNA damage, whereas expression of unphosphorylated Ser 280Ala mutant did not. Finally, FLT3- and Pim-dependent phosphorylation of CHK1 on Ser 280 was confirmed in primary blasts from patients. These results identify a new pathway involved in the resistance of FLT3-ITD leukemic cells to genotoxic agents, and they constitute the first report of CHK1 Ser 280 regulation in myeloid malignancies.


Assuntos
Leucemia Mieloide Aguda/metabolismo , Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas c-pim-1/metabolismo , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem , Duplicação Gênica , Humanos , Espaço Intracelular/metabolismo , Leucemia Mieloide Aguda/genética , Fosforilação , Transporte Proteico , Serina/metabolismo , Transdução de Sinais , Tirosina Quinase 3 Semelhante a fms/metabolismo
8.
Leukemia ; 27(11): 2129-38, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23568147

RESUMO

Previous reports demonstrate that metformin, an anti-diabetic drug, can decrease the risk of cancer and inhibit cancer cell growth. However, its mechanism in cancer cells is still unknown. Metformin significantly blocks cell cycle and inhibits cell proliferation and colony formation of leukemic cells. However, the apoptotic response to metformin varies. Furthermore, daily treatment with metformin induces apoptosis and reduces tumor growth in vivo. While metformin induces early and transient activation of AMPK, inhibition of AMPKα1/2 does not abrogate anti-proliferative or pro-apoptotic effects of metformin. Metformin decreases electron transport chain complex I activity, oxygen consumption and mitochondrial ATP synthesis, while stimulating glycolysis for ATP and lactate production, pentose phosphate pathway for purine biosynthesis, fatty acid metabolism, as well as anaplerotic and mitochondrial gene expression. Importantly, leukemic cells with high basal AKT phosphorylation, glucose consumption or glycolysis exhibit a markedly reduced induction of the Pasteur effect in response to metformin and are resistant to metformin-induced apoptosis. Accordingly, glucose starvation or treatment with deoxyglucose or an AKT inhibitor induces sensitivity to metformin. Overall, metformin elicits reprogramming of intermediary metabolism leading to inhibition of cell proliferation in all leukemic cells and apoptosis only in leukemic cells responding to metformin with AKT phosphorylation and a strong Pasteur effect.


Assuntos
Apoptose/efeitos dos fármacos , Hipoglicemiantes/farmacologia , Leucemia/tratamento farmacológico , Leucemia/patologia , Metformina/farmacologia , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Quinases Ativadas por AMP/antagonistas & inibidores , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Western Blotting , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida , Glucose/metabolismo , Glicólise/efeitos dos fármacos , Humanos , Técnicas Imunoenzimáticas , Ácido Láctico/metabolismo , Leucemia/metabolismo , Camundongos , Camundongos Nus , Mitocôndrias/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , RNA Interferente Pequeno/genética , Espectrometria de Massas por Ionização por Electrospray , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Oncogene ; 32(42): 5123-8, 2013 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-23160377

RESUMO

Cdc25B phosphatases have a key role in G2/M cell-cycle progression by activating the CDK1-cyclinB1 complexes and functioning as important targets of checkpoints. Overexpression of Cdc25B results in a bypass of the G2/M checkpoint and illegitimate entry into mitosis. It can also cause replicative stress, which leads to genomic instability. Thus, fine-tuning of the Cdc25B expression level is critical for correct cell-cycle arrest in response to DNA damage. In response to genotoxic stress, Cdc25B is mainly regulated by post-transcriptional mechanisms affecting either Cdc25B protein stability or translation. Here, we show that upon DNA damage Cdc25B can be regulated at the transcriptional level. Although ionizing radiation downregulates Cdc25B in a p53-dependent pathway, doxorubicin transcriptionally upregulates Cdc25B in p53-proficient cancer cells. We show that in the presence of wild-type p53, doxorubicin activates the Cdc25B promoter by preventing the binding of Sp1 and increasing the binding of NF-Y on the Cdc25B promoter, thus preventing p53 from downregulating this promoter. Our results highlight the mechanistically distinct regulation of the three Cdc25 phosphatases by checkpoint signalling following doxorubicin treatment.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Doxorrubicina/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Fator de Transcrição Sp1/metabolismo , Fosfatases cdc25/genética , Fator de Ligação a CCAAT/genética , Fator de Ligação a CCAAT/metabolismo , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/genética , Doxorrubicina/efeitos da radiação , Genes p53 , Células HCT116/efeitos dos fármacos , Humanos , Regiões Promotoras Genéticas , Fator de Transcrição Sp1/genética , Regulação para Cima , Fosfatases cdc25/metabolismo
10.
Leukemia ; 27(2): 325-35, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22902361

RESUMO

Several receptor tyrosine kinases (TKs) are involved in the pathogenesis of acute myeloid leukemia (AML). Here, we have assessed the expression of the Recepteur d'Origine Nantais (RON) in leukemic cell lines and samples from AML patients. In a series of 86 AML patients, we show that both the full length and/or the short form (sf) of RON are expressed in 51% and 43% of cases, respectively. Interestingly, sfRON is not expressed in normal CD34+ hematopoietic cells and induces part of its oncogenic signaling through interaction with the Src kinase Lyn. sfRON-mediated signaling in leukemic cells also involves mTORC1, the proapoptotic bcl2-family member, BAD, but not the phosphatidylinositol 3-kinase/Akt pathway. Furthermore, the expression of sfRON was specifically downregulated by 5-azacytidine (AZA). Conversely, AZA could induce the expression of sfRON in sfRON-negative leukemic cells suggesting that the activity of this drug in AML and myelodysplastic syndromes could involve modulation of TKs. cMET/RON inhibitors exhibited an antileukemic activity exclusively in AML samples and cell lines expressing sfRON. These results might support clinical trials evaluating cMET/RON inhibitors in AML patients expressing sfRON.


Assuntos
Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Leucemia Mieloide Aguda/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Receptores Proteína Tirosina Quinases/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antimetabólitos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Azacitidina/farmacologia , Western Blotting , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Feminino , Citometria de Fluxo , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Humanos , Imunoprecipitação , Indóis/farmacologia , Leucemia Mieloide Aguda/metabolismo , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina , Pessoa de Meia-Idade , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação/efeitos dos fármacos , Piperazinas/farmacologia , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-met/genética , Proteínas Proto-Oncogênicas c-met/metabolismo , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Receptores Proteína Tirosina Quinases/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Sulfonamidas/farmacologia , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Adulto Jovem , Proteína de Morte Celular Associada a bcl/genética , Proteína de Morte Celular Associada a bcl/metabolismo , Quinases da Família src/genética , Quinases da Família src/metabolismo
11.
Environ Sci Technol ; 45(18): 7670-7, 2011 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-21809844

RESUMO

Radioactive emissions into the atmosphere from the damaged reactors of the Fukushima Dai-ichi nuclear power plant (NPP) started on March 12th, 2011. Among the various radionuclides released, iodine-131 ((131)I) and cesium isotopes ((137)Cs and (134)Cs) were transported across the Pacific toward the North American continent and reached Europe despite dispersion and washout along the route of the contaminated air masses. In Europe, the first signs of the releases were detected 7 days later while the first peak of activity level was observed between March 28th and March 30th. Time variations over a 20-day period and spatial variations across more than 150 sampling locations in Europe made it possible to characterize the contaminated air masses. After the Chernobyl accident, only a few measurements of the gaseous (131)I fraction were conducted compared to the number of measurements for the particulate fraction. Several studies had already pointed out the importance of the gaseous (131)I and the large underestimation of the total (131)I airborne activity level, and subsequent calculations of inhalation dose, if neglected. The measurements made across Europe following the releases from the Fukushima NPP reactors have provided a significant amount of new data on the ratio of the gaseous (131)I fraction to total (131)I, both on a spatial scale and its temporal variation. It can be pointed out that during the Fukushima event, the (134)Cs to (137)Cs ratio proved to be different from that observed after the Chernobyl accident. The data set provided in this paper is the most comprehensive survey of the main relevant airborne radionuclides from the Fukushima reactors, measured across Europe. A rough estimate of the total (131)I inventory that has passed over Europe during this period was <1% of the released amount. According to the measurements, airborne activity levels remain of no concern for public health in Europe.


Assuntos
Poluentes Radioativos do Ar/análise , Radioisótopos de Césio/análise , Radioisótopos do Iodo/análise , Liberação Nociva de Radioativos , Europa (Continente) , Japão , Centrais Nucleares , Monitoramento de Radiação
12.
Aliment Pharmacol Ther ; 34(1): 92-9, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21539589

RESUMO

BACKGROUND: There is recent evidence that mast cells may play important roles in the gut, especially concerning visceral hypersensitivity and motor activity. However, most data are only available for clinical conditions characterised by diarrhoea, where MC have chiefly investigated in the mucosal layer of the colon and there is almost no information concerning constipation. AIM: To investigate mast cells distribution in all colonic layers in controls and severely constipated patients. METHODS: Full-thickness specimens from colons of patients undergoing surgery for slow transit constipation (n=29), compared with controls, were obtained and the number of mast cells (evaluated by specific monoclonal antibodies) counted as a whole and in single colonic segments (caecum, ascending, transverse, descending and sigmoid). RESULTS: Compared with controls, constipated patients revealed significantly higher number of mast cells, both as overall number and in single colonic segments. The distribution of mast cells resulted fairly homogeneous in the various segment of the large bowel, in both controls and patients, and no significant difference in the percentage of degranulated cells was found between groups. CONCLUSIONS: Colonic mast cells display a homogeneous distribution within the viscus. This cell population is shown to increase in severely constipated patients, which might represent a mechanism trying to compensate for the impaired propulsive activity of these patients.


Assuntos
Colo/patologia , Constipação Intestinal/patologia , Trânsito Gastrointestinal , Mastócitos/metabolismo , Mastócitos/patologia , Adulto , Idoso , Anticorpos Monoclonais , Estudos de Casos e Controles , Colo/fisiopatologia , Constipação Intestinal/fisiopatologia , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade
13.
Appl Radiat Isot ; 68(9): 1595-601, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20399107

RESUMO

Very high specific activity (A(S)) (186g)Re could be produced by either proton or deuteron cyclotron irradiation on highly enriched (186)W target in no-carrier-added (NCA) form, leading to a A(S) very close to the theoretical carrier free (CF) value of 6.88GBqmicrog(-1). Thick target yields (TTYs), obtained irradiating both thick metal W targets of natural isotopic composition and highly enriched pressed powdered (186)W targets, were measured at different particles energies taking into account high accuracy and precision on both yield and beam energy. The measurement of radionuclidic purity of (186g)Re obtained activating highly enriched (186)W by both p and d beams were also carried out and accurately compared. The excitation function as thin-target yields (tty, i.e. proportional to the reaction cross-sections) and the integrated TTYs for all Re (A=181, 182, 183, 184, 186 and their metastable levels), W and Ta co-produced radionuclides will be presented elsewhere in deep details.


Assuntos
Deutério/química , Deutério/efeitos da radiação , Marcação por Isótopo/métodos , Radioisótopos/química , Radioisótopos/efeitos da radiação , Rênio/química , Rênio/efeitos da radiação , Ciclotrons , Prótons , Doses de Radiação
14.
Cell Death Differ ; 16(2): 208-18, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18927589

RESUMO

The cellular level of the CDC25A phosphatase is tightly regulated during both the normal and genotoxic-perturbed cell cycle. Here, we describe a caspase-dependent cleavage of this protein at residue D223 in non-genotoxic apoptotic conditions. This specific proteolysis generates a catalytically active C-terminal fragment that localizes to the nuclear compartment. Accumulation of this active CDC25A fragment leads to reduced inhibitory phosphorylation of the CDC25A substrate cyclin-dependent kinase 2 (CDK2) on Tyr15. Moreover, CDK2 was found stably associated with this fragment, as well as with an ectopically expressed CDC25A224-525 truncation mutant that mimicks the cleavage product. Ectopic expression of this mutant induced CDK2 Tyr15 dephosphorylation, whereas its catalytically inactive version did not. Finally, this 224-525 mutant initiated apoptosis when transfected into HeLa cells, whereas its catalytic inactive form did not. Altogether, this study demonstrates for the first time that caspase-dependent cleavage of CDC25A is a central step linking CDK2 activation with non-genotoxic apoptotic induction.


Assuntos
Apoptose , Caspases/metabolismo , Quinase 2 Dependente de Ciclina/metabolismo , Fosfatases cdc25/metabolismo , Células HeLa , Humanos , Células Jurkat , Mutagênese Sítio-Dirigida , Fosforilação , Isoformas de Proteínas/metabolismo , Células U937
15.
Br J Cancer ; 98(6): 1046-52, 2008 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-18283310

RESUMO

This cross-sectional survey aimed to evaluate the prevalence of burnout and estimated psychiatric disorders among haemato-oncology healthcare professionals in Italy. The aspects of work that respondents perceive as stressful and satisfying have also been examined. The assessments were made using the Maslach Burnout Inventory (MBI), General Health Questionnaire and a study-specific questionnaire. Logistic regression models were applied to show associations between different sources of work-related stress and burnout. Three hundred and eighty-seven out of 440 (87.95%) returned their questionnaires. The scores on MBI subscales indicate a high level of emotional exhaustion in 32.2% of the physicians and 31.9% of the nurses; a high level of Depersonalisation in 29.8 and 23.6%, respectively; and a low level of personal accomplishment in 12.4 and 15.3% respectively. The estimated prevalence of psychiatric disorders was 36.4% in physicians and 28.8% in nurses. Statistical analysis confirmed age, sex, personal dissatisfaction, physical tiredness and working with demanding patients to be associated with burnout. In conclusion, haemato-oncology healthcare professionals report a level of burnout and estimated psychiatric morbidity comparable to other oncological areas. Knowledge of the mechanisms of burnout and preventing and dealing with them is therefore a fundamental requirement for the improvement of quality in health services and job satisfaction.


Assuntos
Esgotamento Profissional/epidemiologia , Coleta de Dados , Pessoal de Saúde , Hematologia , Oncologia , Fatores Etários , Humanos , Itália , Satisfação no Emprego , Transtornos Mentais/epidemiologia , Saúde Mental , Enfermeiras e Enfermeiros , Médicos , Qualidade de Vida , Fatores Sexuais
16.
Oncogene ; 27(27): 3811-20, 2008 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-18212737

RESUMO

Acute myeloid leukemia (AML) cells exposed to genotoxic agents arrest their cell cycle at the G2/M checkpoint and are inherently chemoresistant. To understand the mechanism of this chemoresistance, we compared the ability of immature CD34+ versus mature CD34- AML cell lines (KG1a and U937, respectively) to recover from a DNA damage-induced cell cycle checkpoint in G2. Here, we report that KG1a cells have a more stringent G2/M checkpoint response than U937 cells. We show that in both cell types, the CDC25B phosphatase participates in the G2/M checkpoint recovery and that its expression is upregulated. Furthermore, we show that CHK1 inhibition by UCN-01 in immature KG1a cells allows checkpoint exit and induces sensitivity to genotoxic agents. Similarly, UCN-01 treatment potentializes genotoxic-induced inhibition of colony formation efficiency of primary leukemic cells from AML patients. Altogether, our results demonstrate that checkpoint stringency varies during the maturation process and indicate that targeting checkpoint mechanisms might represent an attractive therapeutic opportunity for chemoresistant immature AML cells.


Assuntos
Divisão Celular , Fase G2 , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Antígenos CD/análise , Antígenos CD34/análise , Antineoplásicos/toxicidade , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ensaio de Unidades Formadoras de Colônias , Humanos , Mitose/efeitos dos fármacos , Nocodazol/farmacologia , Estaurosporina/análogos & derivados , Estaurosporina/toxicidade , Células U937 , Fosfatases cdc25/metabolismo
17.
Leukemia ; 20(7): 1211-6, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16688229

RESUMO

Activation of the Wnt/beta-catenin pathway has recently been shown to be crucial to the establishment of leukemic stem cells in chronic myeloid leukemia. We sought to determine whether beta-catenin was correlated to clonogenic capacity also in the acute myeloid leukemia (AML) setting. Eighty-two patients were retrospectively evaluated for beta-catenin expression by Western blot. beta-Catenin was expressed (although at various protein levels) in 61% of patients, and was undetectable in the remaining cases. In our cohort, beta-catenin expression was correlated with the clonogenic proliferation of AML-colony forming cells (AML-CFC or CFU-L) in methylcellulose in the presence of 5637-conditioned medium, and more strikingly with self-renewing of leukemic cells, as assessed in vitro by a re-plating assay. In survival analyses, beta-catenin appeared as a new independent prognostic factor predicting poor event-free survival and shortened overall survival (both with P<0.05). Furthermore, variations in beta-catenin protein levels were dependent on post-transcriptional mechanisms involving the Wnt/beta-catenin pathway only in leukemic cells. Indeed, beta-catenin negative leukemic cells were found to increase beta-catenin in response to Wnt3a agonist in contrast to normal counterparts. Altogether, our data pave the way to the evaluation of Wnt pathway inhibition as a new rationale for eradicating the clonogenic pool of AML cells.


Assuntos
Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Células-Tronco Neoplásicas/fisiologia , beta Catenina/genética , Linhagem Celular Tumoral , Células Clonais , Feminino , Regulação Leucêmica da Expressão Gênica , Humanos , Leucemia Monocítica Aguda/metabolismo , Leucemia Monocítica Aguda/mortalidade , Leucemia Monocítica Aguda/patologia , Leucemia Mieloide Aguda/metabolismo , Leucemia Mielomonocítica Aguda/metabolismo , Leucemia Mielomonocítica Aguda/mortalidade , Leucemia Mielomonocítica Aguda/patologia , Masculino , Pessoa de Meia-Idade , Células-Tronco Neoplásicas/patologia , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Transdução de Sinais , Análise de Sobrevida , Proteínas Wnt/metabolismo
18.
Oncogene ; 25(22): 3113-22, 2006 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-16407823

RESUMO

Relapses following chemotherapy are a major hindrance to patients' survival in acute myeloid leukemia (AML). To investigate the role of the hematopoietic niche in the chemoresistance of leukemic cells, we examined two pathways: one mediated by adhesion molecules/integrins, and the other by soluble factors of the morphogen Wnt pathway. In our study, both the adhesion of leukemic blasts to fibronectin and the addition of Wnt antagonists induced, independently, resistance of AML cells to daunorubicin in a cell survival assay. Using pharmacological inhibitors and siRNA, we showed that both resistance pathways required the activity of the glycogen synthase kinase 3beta (GSK3beta). Moreover, the AML cell protection downstream of GSK3beta was mediated by NF-kappaB. A link between the adhesion and the Wnt pathway was found, as adhesion of U937 on human osteoblasts, a component of the hematopoietic niche, triggered the secretion of the Wnt antagonist sFRP-1 and supported resistance to daunorubicin. The osteoblast-conditioned medium could also confer chemoresistance to U937 cells cultured in suspension, and this cell protective effect was abrogated after depletion of sFRP-1. In the context of this potential double in vivo resistance, modulators of the common signal GSK3beta and of its target NF-kappaB could represent important novel therapeutic tools.


Assuntos
Adesão Celular/efeitos dos fármacos , Daunorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos , Leucemia Mieloide Aguda/tratamento farmacológico , Transdução de Sinais , Proteínas Wnt/metabolismo , Antibióticos Antineoplásicos/farmacologia , Crise Blástica , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Meios de Cultivo Condicionados/farmacologia , Fibronectinas/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Proteínas de Membrana/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , Osteoblastos/citologia , Osteoblastos/metabolismo , RNA Interferente Pequeno/farmacologia , Células U937/metabolismo
19.
Curr Pharm Des ; 11(16): 2119-34, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15974963

RESUMO

The microenvironment is now considered as an important source of potential therapeutic targets in diverse pathologies. In cardiovascular diseases and in cancer, common processes involving stromal remodeling, cell invasion, and angiogenesis can promote progression of the pathology. At each step of the pathogenesis, cell adhesion needs to be modulated to allow adaptation of cell survival/motility/proliferation functions to the microenvironment. Among adhesion receptors, integrins, responsible for cell/matrix or cell/cell interactions, play a key role in the cellular responses. Moreover, their engagement conditions the sensitivity to apoptosis induced by therapeutic drugs. Targeting of the extracellular side of integrins in order to modulate their adhesive functions is under development and has reached clinical indications. However, improvement of oral availability and of cell signaling control is required in the future. Targeting of the extracellular or the intracellular key proteins involved in integrin-dependent signaling pathway seems promising. Yet, although some common key enzyme inhibitors are under development, a better knowledge of the specificity of integrin activation and interaction with partners upon pathogenesis is of major importance in envisaging the antagonism of integrin-linked signals as a therapeutic tool alone or in association with other therapies.


Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Integrinas/fisiologia , Neoplasias/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Doenças Cardiovasculares/fisiopatologia , Humanos , Neoplasias/fisiopatologia , Transdução de Sinais/fisiologia
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