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1.
Appl Opt ; 59(14): 4271-4278, 2020 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-32400400

RESUMEN

This paper presents a novel, to the best of our knowledge, and simple technique for achieving a higher spectral resolution in classical static Fourier transform spectrometers. This is achieved by heterodyning the frequency of a standard interferogram to a lower spatial frequency by placing a single transmission grating at the image plane of two mutually coherent beams produced by the interferometer. The grating splits the beams into diffraction orders, which overlap to produce the heterodyned interferogram, similar to that seen in techniques such as spatial heterodyne spectroscopy. The increase in spectral resolution for such a system is shown to be related to the angle between the beams and the groove period of the transmission grating. The theoretical performance of this design is compared with a proof-of-concept system built using off-the-shelf components and tested at visible wavelengths. The experimental results agree well with those produced from a theoretical simulation.

2.
J Chem Phys ; 147(22): 224303, 2017 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-29246058

RESUMEN

The single-photon, photoelectron-photoion coincidence spectrum of N2 has been recorded at high (∼1.5 cm-1) resolution in the region between the N2+ X Σg2+, v+ = 0 and 1 ionization thresholds by using a double-imaging spectrometer and intense vacuum-ultraviolet light from the Synchrotron SOLEIL. This approach provides the relative photoionization cross section, the photoelectron energy distribution, and the photoelectron angular distribution as a function of photon energy. The region of interest contains autoionizing valence states, vibrationally autoionizing Rydberg states converging to vibrationally excited levels of the N2+ X Σg2+ ground state, and electronically autoionizing states converging to the N2+A2Π and B 2Σu+ states. The wavelength resolution is sufficient to resolve rotational structure in the autoionizing states, but the electron energy resolution is insufficient to resolve rotational structure in the photoion spectrum. A simplified approach based on multichannel quantum defect theory is used to predict the photoelectron angular distribution parameters, ß, and the results are in reasonably good agreement with experiment.

3.
J Chem Phys ; 145(2): 024306, 2016 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-27421404

RESUMEN

Resonantly enhanced multiphoton ionization via the EF(1)Σg (+), v' = 6 double-well state has been used to probe the energy region below the third dissociation limit of H2 where several high vibrational levels of the 4(1)Σu (+) state are expected. Theoretical ab initio potential energy curves for this state predict a deep inner well and shallow outer well where vibrational levels above v = 8 are expected to exhibit the double-well character of the state. Since the 4(1)Σu (+) state has f-state character, transitions to it from the ground state are nominally forbidden. However, the d character of the outer well of the EF(1)Σg (+) state allows access to this state. We report observations of transitions to the v = 9-12 levels of the 4(1)Σu (+) state and compare their energies to predicted energies calculated from an ab initio potential energy curve with adiabatic corrections. Assignments are based on measured energies and linewidths, rotational constants, and expected transition strengths. The amount of agreement between the predicted values and the observations is mixed, with the largest discrepancies arising for the v = 9 level, owing to strong nonadiabatic electronic mixing in this energy region.

4.
J Chem Phys ; 144(1): 014307, 2016 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-26747806

RESUMEN

Double-resonance laser spectroscopy via the EF (1)Σg (+),v(')=6,J(')=0-2 state was used to probe the high vibrational levels of the B('')B̄ (1)Σu (+) state of molecular hydrogen. Resonantly enhanced multiphoton ionization spectra were recorded by detecting ion production as a function of energy using a time of flight mass spectrometer. New measurements of energies for the v = 51-66 levels for the B('')B̄ state of H2 are reported, which, taken with previous results, span the v = 46-69 vibrational levels. Results for energy levels are compared to theoretical close-coupled calculations [L. Wolniewicz, T. Orlikowski, and G. Staszewska, J. Mol. Spectrosc. 238, 118-126 (2006)]. The average difference between the 84 measured energies and calculated energies is -3.8 cm(-1) with a standard deviation of 5.3 cm(-1). This level of agreement showcases the success of the theoretical calculations in accounting for the strong rovibronic mixing of the (1)Σu (+) and (1)Πu (+) states. Due to the ion-pair character of the outer well, the observed energies of the vibrational levels below the third dissociation limit smoothly connect with previously observed energies of ion-pair states above this limit. The results provide an opportunity for testing a heavy Rydberg multi-channel quantum defect analysis of the high vibrational states below the third dissociation limit.

5.
J Chem Phys ; 137(3): 034306, 2012 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-22830701

RESUMEN

A continuous wave quantum cascade laser (cw-QCL) operating at 10 µm has been used to record absorption spectra of low pressure samples of OCS in an astigmatic Herriott cell. As a result of the frequency chirp of the laser, the spectra show clearly the effects of rapid passage on the absorption line shape. At the low chirp rates that can be obtained with the cw-QCL, population transfer between rovibrational quantum states is predicted to be much more efficient than in typical pulsed QCL experiments. This optical pumping is investigated by solving the Maxwell Bloch equations to simulate the propagation of the laser radiation through an inhomogeneously broadened two-level system. The calculated absorption profiles show good quantitative agreement with those measured experimentally over a range of chirp rates and optical thicknesses. It is predicted that at a low chirp rate of 0.13 MHz ns(-1), the population transfer between rovibrational quantum states is 12%, considerably more than that obtained at the higher chirp rates utilised in pulsed QCL experiments.

6.
Neuropathol Appl Neurobiol ; 37(2): 189-205, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20819169

RESUMEN

AIMS: brain metastasis is a common cause of mortality in cancer patients, and associated with poor prognosis. Our objective was to develop a clinically relevant animal model by transplanting human biopsy spheroids derived from metastatic lesions into brains of immunodeficient rats. METHODS: nine different patient brain metastases from four different primary cancers were implanted into brains of immunodeficient rats. The xenografts were compared with patient tumours by magnetic resonance imaging, histochemistry, immunohistochemistry and DNA copy number analysis. RESULTS: after transplantation, tumour growth was achieved in seven out of nine human brain metastases. Spheroids derived from four of the metastases initiated in the rat brains were further serially transplanted into new animals and a 100% tumour take was observed during second passage. Three of the biopsies were implanted subcutaneously, where no tumour take was observed. The animal brain metastases exhibited similar radiological features as observed clinically. Histological comparisons between the primary tumours from the patients, the patient brain metastases and the derived xenografts showed striking similarities in histology and growth patterns. Also, immunohistochemistry showed a strong marker expression similarity between the patient tumours and the corresponding xenografts. DNA copy number analysis between the brain metastases, and the corresponding xenografts revealed strong similarities in gains and losses of chromosomal content. CONCLUSION: we have developed a representative in vivo model for studying the growth of human metastatic brain cancers. The model described represents an important tool to assess responses to new treatment modalities and for studying mechanisms behind metastatic growth in the central nervous system.


Asunto(s)
Neoplasias Encefálicas/secundario , Modelos Animales de Enfermedad , Ensayos Antitumor por Modelo de Xenoinjerto , Animales , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Dosificación de Gen , Humanos , Inmunohistoquímica , Microscopía Confocal , Análisis de Secuencia por Matrices de Oligonucleótidos , Ratas , Análisis de Matrices Tisulares , Células Tumorales Cultivadas
7.
Opt Lett ; 36(24): 4725-7, 2011 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-22179863

RESUMEN

Two 5 µm continuous wave quantum cascade lasers are used to perform a counterpropagating pump and probe experiment on a low pressure sample of nitric oxide. The strong pump field excites a fundamental rovibrational transition and the weaker probe field is tuned to the corresponding rotationally resolved hot band transition. When both light fields are in resonance, rapid passage is observed in the hot band absorption lineshape arising from a minimally damped and velocity-selected sample of molecules in the v=1 state. The measured rapid passage signals are well described by a two-level model based on the optical Bloch equations.

8.
J Phys Chem A ; 114(42): 11175-88, 2010 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-20593817

RESUMEN

The ionization of H(2) Rydberg states at a metal surface is investigated using a molecular beam incident at grazing incidence on a gold surface. The H(2) molecules, excited by stepwise two-color laser excitation, are selected in each of the accessible Stark eigenstates of the N(+) = 2, n = 17 Rydberg manifold in turn and the ionization at the surface is characterized by applying a field to extract the ions formed. Profiles of extracted ion signal versus applied field show resonances that can be simulated by assuming an enhancement of surface ionization at fields corresponding to energy-level crossings between the populated N(+) = 2 manifold and the near-degenerate N(+) = 0 Stark manifolds. It is concluded that the slow (microsecond time scale) rotation-electronic energy transfer to N(+) = 0 states occurring at these crossings takes place in the time interval following application of the field ramp when the molecule is still distant from, and unperturbed by, the surface. However, the energy levels are strongly perturbed by image-dipole interactions as the molecule approaches close to the surface, leading to additional energy-level crossings. Adiabatic behavior at such crossings affects the intensity of the observed resonances in the surface ionization signal but not their field positions. Resonances are also observed in the surface ionization profiles at fields above the field-ionization threshold; some of these show asymmetric "Fano-type" line shapes due to quantum interference in the nonradiative coupling to degenerate bound and continuum states.


Asunto(s)
Oro/química , Hidrógeno/química , Teoría Cuántica , Propiedades de Superficie
9.
Gene ; 699: 110-114, 2019 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-30844479

RESUMEN

Tricho-hepatic-enteric syndrome (THES) is a genetically heterogeneous rare syndrome (OMIM: 222470 (THES1) and 614602 (THES2)) that typically presents in the neonatal period with intractable diarrhoea, intra-uterine growth retardation (IUGR), facial dysmorphism, and hair and skin changes. THES is associated with pathogenic variants in either TTC37 or SKIV2L; both are components of the human SKI complex, an RNA exosome cofactor. We report an 8 year old girl who was diagnosed with THES by the Undiagnosed Disease Program-WA with compound heterozygous pathogenic variants in SKIV2L. While THES was considered in the differential diagnosis, the absence of protracted diarrhoea delayed definitive diagnosis. We therefore suggest that SKIV2L testing should be considered in cases otherwise suggestive of THES, but without the characteristic diarrhoea. We expand the phenotypic spectrum while reviewing the current knowledge on SKIV2L.


Asunto(s)
Diarrea Infantil/diagnóstico , Diarrea Infantil/genética , Diarrea/diagnóstico , Diarrea/genética , Retardo del Crecimiento Fetal/diagnóstico , Retardo del Crecimiento Fetal/genética , Enfermedades del Cabello/diagnóstico , Enfermedades del Cabello/genética , ADN Helicasas/genética , Facies , Heterocigoto , Humanos
10.
Leukemia ; 19(5): 687-706, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15759039

RESUMEN

From the early inception of the transplant models through to contemporary genetic and xenograft models, evolution of murine leukaemic model systems have been critical to our general comprehension and treatment of cancer, and, more specifically, disease states such as acute myelogenous leukaemia (AML). However, even with modern advances in therapeutics and molecular diagnostics, the majority of AML patients die from their disease. Thus, in the absence of definitive in vitro models which precisely recapitulate the in vivo setting of human AMLs and failure of significant numbers of new drugs late in clinical trials, it is essential that murine AML models are developed to exploit more specific, targeted therapeutics. While various model systems are described and discussed in the literature from initial transplant models such as BNML and spontaneous murine leukaemia virus models, to the more definitive genetic and clinically significant NOD/SCID xenograft models, there exists no single compendium which directly assesses, reviews or compares the relevance of these models. Thus, the function of this article is to provide clinicians and experimentalists a chronological, comprehensive appraisal of all AML model systems, critical discussion on the elucidation of their roles in our understanding of AML and consideration to their efficacy in the development of AML chemotherapeutics.


Asunto(s)
Modelos Animales de Enfermedad , Leucemia Mieloide Aguda , Animales , Ingeniería Genética , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Leucemia Mieloide Aguda/terapia , Trasplante de Neoplasias , Ensayos Antitumor por Modelo de Xenoinjerto
11.
Oncogene ; 5(3): 377-86, 1990 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-1690379

RESUMEN

A series of monoclonal antibodies (mAbs) against transforming growth factor alpha (TGF alpha) have been produced. The generation of these reagents, as well as their biochemical and immunochemical characterization is described. TGF alpha peptides, mutant recombinant TGF alpha proteins and two-site immunoradiometric assays were used to identify the epitopes recognized by each antibody. This approach has allowed the specific localization of immunodominant domains on the molecule. Certain mAbs were found to be useful for selected procedures. mAb 134A-2B3 was used for immunoblotting both the precursor and mature forms of TGF alpha from conditioned media of tumor cells. One mAb 189-2130.1, which reacted with the carboxyl terminal seventeen amino acids, was able to block TGF alpha binding to the EGF receptor. mAb 213-4.4 was used for immunohistochemical detection of TGF alpha in fixed tumor cells. mAbs 137-178 and 134A-2B3 were used to develop a two-site immunoradiometric immunoassay which was sensitive to 1 ng ml-1 and detected TGF alpha from a variety of tumor cells. A series of mAbs such as these could prove useful in studying the biochemical properties as well as the immunochemical localization of TGF alpha in normal tissues and tumors.


Asunto(s)
Anticuerpos Monoclonales , Epítopos/análisis , Factores de Crecimiento Transformadores/análisis , Animales , Anticuerpos Monoclonales/inmunología , Línea Celular , Clonación Molecular , Ensayo de Inmunoadsorción Enzimática , Receptores ErbB/metabolismo , Escherichia coli/genética , Técnica del Anticuerpo Fluorescente , Genes , Humanos , Hibridomas/inmunología , Immunoblotting , Isotipos de Inmunoglobulinas/inmunología , Ratones , Ratones Endogámicos BALB C/inmunología , Proteínas Recombinantes/análisis , Proteínas Recombinantes/inmunología , Factores de Crecimiento Transformadores/genética , Factores de Crecimiento Transformadores/inmunología
12.
Front Biosci ; 2: a37-45, 1997 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-9351895

RESUMEN

Reversible inhibitors of the cell cycle such as the TGF-betas have been exploited to protect dividing cells from exposure to anticancer drugs and radiation. Here, rat embryo fibroblast (REF) lines expressing different p53 mutations were used to test whether the p53 growth arrest could also chemoprotect cells from high doses of anticancer drugs. Whereas the doubling times of the different REF lines at 37 degrees C were similar, cells bearing temperature-sensitive mutations (mouse 135V or human 143A) were growth arrested at 31 degrees C. Temperature-dependent p53 activity was associated with increased levels of MDM2 and p21/WAF1, and the induction of an integrated p53-responsive luciferase gene. The REF lines exhibited similar sensitivities to common anticancer drugs when grown at 37 degrees C. However, when exposed to the same agents following transient incubation at 31 degrees C, the p53-arrested cells exhibited a marked survival advantage as shown by colony-forming assays. Chemoprotection was not universal, in that colony formation was not enhanced significantly after treatment with cisplatin or 5-fluorouracil, two drugs which can cause cellular damage throughout the cell cycle. Like other negative growth regulators, an activated p53 checkpoint may mediate the survival of cells exposed to drugs that target DNA synthesis or mitosis.


Asunto(s)
Antineoplásicos/toxicidad , Proteína p53 Supresora de Tumor/fisiología , Animales , Técnicas de Cultivo de Célula , Supervivencia Celular , ADN/biosíntesis , Fibroblastos , Mitosis , Ratas/embriología , Células Madre , Temperatura , Proteína p53 Supresora de Tumor/biosíntesis , Proteína p53 Supresora de Tumor/genética
13.
Biochem Pharmacol ; 53(8): 1149-59, 1997 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-9175720

RESUMEN

The transforming growth factor-beta (TGF-beta) family of regulatory growth factors can reversibly arrest cell division in the G1 phase of the cell cycle. Previously, TGF-beta3 was shown to protect epithelial cells and hematopoietic cells from cytotoxic damage in vitro and in vivo, and to reduce the severity and duration of oral mucositis induced by 5-fluorouracil (5-FU) in vivo. In the present study, we tested whether TGF-beta3 can protect epithelial cells from a range of chemotherapy drugs with differing mechanisms of action, using the CCL64 cell line as a model system. We report that preincubation of cells with TGF-beta3 for 24 hr resulted in enhanced clonogenicity following exposure to vinblastine, vincristine, etoposide, taxol, ara-C, methotrexate, or 5-FU. Protection was measured in colony-forming assays, which demonstrated that the protected cells could re-enter the cell cycle and undergo multiple rounds of cell division. At high cytotoxic drug concentrations, absolute colony counts were increased for the cultures prearrested by TGF-beta3, as compared with the proliferating control cultures. The effects of TGF-beta3 were reduced for cisplatin and doxorubicin, drugs that are toxic to cells throughout the cell cycle. Thus, TGF-beta3 can effectively reduce the cytotoxicity of anticancer drugs that act predominantly in S or M phase of the cell cycle.


Asunto(s)
Antineoplásicos/farmacología , Factor de Crecimiento Transformador beta/farmacología , Animales , Antimetabolitos Antineoplásicos/farmacología , Antineoplásicos Fitogénicos/farmacología , Ciclo Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Epitelio/efectos de los fármacos , Visón , Fase S
14.
Br J Radiol ; 87(1044): 20140239, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25270608

RESUMEN

OBJECTIVE: Phyllodes tumours (PTs) are rare neoplasms accounting for <1% of breast lesions. With increased breast awareness and screening programmes, smaller PTs are being detected. The purpose of this study was to determine the clinical, radiological and pathological presentation of PTs and to evaluate the role of imaging follow-up, for which there are no specific guidelines. METHODS: A retrospective study of all patients diagnosed with PT in a symptomatic unit between January 2006 and March 2013 was carried out. Patients were identified using breast care and electronic patient record databases. RESULTS: 53 patients with 54 lesions were diagnosed as having a PT. The median age was 27.5, 35.0 and 38.5 years for benign, borderline and malignant PT, respectively. Borderline and malignant PTs were larger than benign PTs, with mean sizes of 33 and 42 mm compared with 29 mm. 38% of PTs were labelled by the reporting radiologist as fibroadenomas, including two borderline PTs and one malignant PT. In 24% of cases, the radiologist raised the possibility of PT in the report. 17 patients (40%) developed a new fibroepithelial breast lesion during follow-up of which 4 were recurrent PTs. CONCLUSION: Despite adequate surgical management, the development of further fibroepithelial lesions in the ipsilateral breast is common. 3-year clinical surveillance, with the addition of 6-monthly ultrasound is advised for females with initial borderline or malignant PT histology. ADVANCES IN KNOWLEDGE: We propose a follow-up protocol with ultrasound based on the grade of the PT diagnosed for 3 years to detect recurrence.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Mamografía/métodos , Mastectomía/métodos , Tumor Filoide/diagnóstico por imagen , Adolescente , Adulto , Neoplasias de la Mama/cirugía , Registros Electrónicos de Salud , Femenino , Estudios de Seguimiento , Humanos , Persona de Mediana Edad , Tumor Filoide/cirugía , Pronóstico , Estudios Retrospectivos , Adulto Joven
15.
Cancer Gene Ther ; 21(11): 457-62, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25277132

RESUMEN

Our phase I Hepatic Immunotherapy for Metastases (HITM) trial tested the safety of chimeric antigen receptor-modified T-cell (CAR-T) hepatic artery infusions (HAI) for unresectable carcinoembryonic antigen (CEA)+ liver metastases (LM). High neutrophil:lymphocyte ratios (NLR) predict poor outcome in cancer patients and we hypothesized that NLR changes would correlate with early responses to CAR-T HAI. Six patients completed the protocol. Three patients received CAR-T HAI in dose escalation (1 × 10(8), 1 × 10(9) and 1 × 10(10) cells) and the remainder received three doses (1 × 10(10) cells) with interleukin (IL)2 support. Serum cytokines and NLR were measured at multiple time points. The mean NLR for all patients was 13.9 (range 4.8-38.1). NLR increased in four patients following treatment with a mean fold change of 1.9. Serum IL6 levels and NLR fold changes demonstrated a trend towards a positive correlation (r=0.77, P=0.10). Patients with poor CEA responses were significantly more likely to have higher NLR level increases (P=0.048). Increased NLR levels were associated with poor responses following CAR-T HAI. NLR variations and associated cytokine changes may be useful surrogates of response to CAR-T HAI.


Asunto(s)
Arteria Hepática/metabolismo , Inmunoterapia/métodos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/inmunología , Neoplasias Hepáticas/secundario , Receptores de Antígenos de Linfocitos T/uso terapéutico , Proteínas Recombinantes de Fusión/uso terapéutico , Biomarcadores de Tumor/sangre , Recuento de Células Sanguíneas , Citocinas/sangre , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Infusiones Intraarteriales/métodos , Interleucina-17/sangre , Interleucina-6/sangre , Linfocitos/citología , Masculino , Persona de Mediana Edad , Neutrófilos/citología , Pronóstico
16.
Cell Death Dis ; 4: e516, 2013 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-23449452

RESUMEN

We show that cyclic AMP (cAMP) elevating agents protect blasts from patients with acute promyelocytic leukemia (APL) against death induced by first-line anti-leukemic anthracyclines like daunorubicin (DNR). The cAMP effect was reproduced in NB4 APL cells, and shown to depend on activation of the generally cytoplasmic cAMP-kinase type I (PKA-I) rather than the perinuclear PKA-II. The protection of both NB4 cells and APL blasts was associated with (inactivating) phosphorylation of PKA site Ser118 of pro-apoptotic Bad and (activating) phosphorylation of PKA site Ser133 of the AML oncogene CREB. Either event would be expected to protect broadly against cell death, and we found cAMP elevation to protect also against 2-deoxyglucose, rotenone, proteasome inhibitor and a BH3-only mimetic. The in vitro findings were mirrored by the findings in NSG mice with orthotopic NB4 cell leukemia. The mice showed more rapid disease progression when given cAMP-increasing agents (prostaglandin E2 analog and theophylline), both with and without DNR chemotherapy. The all-trans retinoic acid (ATRA)-induced terminal APL cell differentiation is a cornerstone in current APL treatment and is enhanced by cAMP. We show also that ATRA-resistant APL cells, believed to be responsible for treatment failure with current ATRA-based treatment protocols, were protected by cAMP against death. This suggests that the beneficial pro-differentiating and non-beneficial pro-survival APL cell effects of cAMP should be weighed against each other. The results suggest also general awareness toward drugs that can affect bone marrow cAMP levels in leukemia patients.


Asunto(s)
Antibióticos Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , AMP Cíclico/metabolismo , Daunorrubicina/farmacología , 1-Metil-3-Isobutilxantina/farmacología , Animales , Antibióticos Antineoplásicos/uso terapéutico , Línea Celular Tumoral , AMP Cíclico/agonistas , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Proteína Quinasa Tipo I Dependiente de AMP Cíclico/metabolismo , Proteína Quinasa Tipo II Dependiente de AMP Cíclico/antagonistas & inhibidores , Proteína Quinasa Tipo II Dependiente de AMP Cíclico/genética , Proteína Quinasa Tipo II Dependiente de AMP Cíclico/metabolismo , Daunorrubicina/uso terapéutico , Dinoprostona/análogos & derivados , Dinoprostona/farmacología , Dinoprostona/uso terapéutico , Progresión de la Enfermedad , Células HL-60 , Humanos , Leucemia Promielocítica Aguda/tratamiento farmacológico , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patología , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Teofilina/farmacología , Teofilina/uso terapéutico , Trasplante Heterólogo , Tretinoina/farmacología , Tretinoina/uso terapéutico , Proteína Letal Asociada a bcl/metabolismo
17.
Leukemia ; 26(5): 910-7, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22064349

RESUMEN

Although TP53 mutations are rare in acute myeloid leukemia (AML), wild type p53 function is habitually annulled through overexpression of MDM2 or through various mechanisms including epigenetic silencing by histone deacetylases (HDACs). We hypothesized that co-inhibition of MDM2 and HDACs, with nutlin-3 and valproic acid (VPA) would additively inhibit growth in leukemic cells expressing wild type TP53 and induce p53-mediated apoptosis. In vitro studies with the combination demonstrated synergistic induction of apoptosis in AML cell lines and patient cells. Nutlin-3 and VPA co-treatment resulted in massive induction of p53, acetylated p53 and p53 target genes in comparison with either agent alone, followed by p53 dependent cell death with autophagic features. In primary AML cells, inhibition of proliferation by the combination therapy correlated with the CD34 expression level of AML blasts. To evaluate the combination in vivo, we developed an orthotopic, NOD/SCID IL2rγ(null) xenograft model of MOLM-13 (AML FAB M5a; wild type TP53) expressing firefly luciferase. Survival analysis and bioluminescent imaging demonstrated the superior in vivo efficacy of the dual inhibition of MDM2 and HDAC in comparison with controls. Our results suggest the concomitant targeting of MDM2-p53 and HDAC inhibition, may be an effective therapeutic strategy for the treatment of AML.


Asunto(s)
Apoptosis/efectos de los fármacos , Genes p53 , Imidazoles/farmacología , Leucemia Mieloide Aguda/patología , Piperazinas/farmacología , Ácido Valproico/farmacología , Acetilación , Animales , Antígenos CD34/metabolismo , Apoptosis/genética , Línea Celular Tumoral , Citometría de Flujo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Inhibidores de Histona Desacetilasas/farmacología , Humanos , Leucemia Mieloide Aguda/genética , Ratones , Ratones Endogámicos NOD , Ratones SCID , Microscopía Electrónica de Transmisión , Proteínas Proto-Oncogénicas c-mdm2/antagonistas & inhibidores
18.
FEBS Lett ; 583(4): 782-6, 2009 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-19183552

RESUMEN

Actin is dependent on the type-II chaperonin CCT (chaperonin containing TCP-1) to reach its native state. In vitro, yeast CCT folds yeast and also mammalian cytoplasmic (beta/gamma) actins but is now found to be incapable of folding mammalian skeletal muscle alpha-actin. Arrest of alpha-actin on yeast CCT at a folding cycle intermediate has been observed by electron microscopy. This discovery explains previous observations in vivo that yeast mutants expressing only the muscle actin gene are non-viable. Mutational analysis identified a single specific alpha-actin residue, Asn-297, that confers this species/isoform folding specificity. The implications of this incompatibility for chaperonin mechanism and actin-CCT co-evolution are discussed.


Asunto(s)
Actinas/química , Actinas/metabolismo , Aminoácidos/metabolismo , Chaperoninas/química , Chaperoninas/metabolismo , Actinas/genética , Actinas/aislamiento & purificación , Actinas/ultraestructura , Secuencia de Aminoácidos , Animales , Asparagina/metabolismo , Chaperonina con TCP-1 , Chaperoninas/genética , Chaperoninas/aislamiento & purificación , Chaperoninas/ultraestructura , Escherichia coli/genética , Humanos , Modelos Moleculares , Datos de Secuencia Molecular , Músculo Esquelético/química , Mutación , Conformación Proteica , Pliegue de Proteína , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Conejos , Saccharomyces cerevisiae/metabolismo , Homología de Secuencia de Aminoácido , Termodinámica
19.
Transplant Proc ; 41(9): 3863-7, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19917402

RESUMEN

BACKGROUND: Tandem high-dose melphalan therapy with autologous peripheral stem cell support has emerged as the standard of care for patients without prohibitive comorbidities. Mucositis and gastrointestinal side effects are the most common extrahematologic side effects. Two previously published studies presented a triple transplant with a conditioning regimen of melphalan 100 mg/m(2) (MEL100) with peripheral stem cell support every 2 to 5 months for patients with prohibitive comorbidities for high-dose tandem transplantation. We present a novel approach that investigates the triple melphalan 100/m(2) approach on a dose-dense, every-3-weeks schedule in a patient population without significant comorbidities. PATIENTS AND METHODS: Thirteen standard or high-risk patients with stage III multiple myeloma were prospectively treated. This population contained eight patients with immunoglobin G clonality, three immunoglobin A, one nonsecretory, and one light chain isotype. The induction regimens of the 13 patients were heterogenous and included five VAD, three DCIE, two Thal/Dex, two CIE, and one pulse decadron. Patients underwent peripheral blood leukopheresis, and these cells were divided into three equal sets and frozen. The patients were scheduled to receive melphalan at 100 mg/m(2) on days 1, 20, and 41, and then the autologous infusions occurred at days 0, 21, and 42. RESULTS: All patients were able to receive all three cycles of the MEL100 regimen. Seven patients (54%) received the treatments on the every-3-weeks schedule; three treatments (23%) during the second cycle and six treatments (46%) of the third cycle had to be delayed a median of 6 and 4 days, respectively. Three patients were managed completely in the outpatient setting, and the average total hospital stay for the three transplants was 18 days. Median progression-free survival was 854 days (range 73 to 1571), and the overall survival of this cohort has yet to be reached. No patient had worse than grade II mucositis, and no serious adverse events were recorded. CONCLUSION: Our regimen of three consecutive autologous peripheral stem cell transplants with a reduced dose of melphalan at 100 mg/m(2) given every 3 weeks was very well tolerated. The progression-free survival and overall survival are similar and can be compared favorably with the standard tandem myeloma regimens. Our data is intriguing, and further studies with larger numbers need to be performed to confirm these results.


Asunto(s)
Melfalán/uso terapéutico , Mieloma Múltiple/tratamiento farmacológico , Mieloma Múltiple/cirugía , Antineoplásicos Alquilantes/administración & dosificación , Antineoplásicos Alquilantes/uso terapéutico , Terapia Combinada , Progresión de la Enfermedad , Esquema de Medicación , Humanos , Melfalán/administración & dosificación , Mieloma Múltiple/mortalidad , Mieloma Múltiple/patología , Estadificación de Neoplasias , Trasplante de Células Madre , Trasplante Autólogo
20.
Oncogene ; 27(27): 3765-79, 2008 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-18264136

RESUMEN

The use of genetically engineered mice (GEM) have been critical in understanding disease states such as cancer, and none more so than acute myelogenous leukaemia (AML), a disease characterized by over 100 distinct chromosomal translocations. A substantial proportion of cases exhibiting recurrent reciprocal translocations at diagnosis, such as t(8;21) or t(15;17) have been exhaustively studied and are currently employed in clinical diagnosis. However, a definitive conclusion regarding the leukaemogenic potential of defined transgenes for this disease remains elusive. While it is increasingly apparent that a number of cooperating mutations are necessary to develop a leukaemic phenotype, the number of models reflecting these synergisms remains few. Furthermore, little emphasis has been paid to the effect of chromosomal translocations other than recurrent genetic abnormalities, with no models reflecting the multiple abnormalities observed in high-risk cases of AML accounting for 8-10% of adult AML. Here we review the differing technologies employed in generation of GEM of AML. We discuss the relevance of GEM AML from embryonic stem cell-mediated (for example retinoic acid receptor-alpha fusions and AML1/ETO) models; through to the valuable retroviral-mediated gene transfer models. The latter have been used to great effect in defining the transforming properties of chromosomal translocation products such as MLL (found in 5-6% of all AML cases) and NUP98 (denoting poor prognosis in therapy-related disease) and particularly when co-transduced with bad prognostic factors such as Flt3 mutations. Finally, we comment on the emergence of newer transduction technologies, which can regulate the level of expression to defined cell lineages in both primary murine and human xenografts, and discuss how combining multiple genetic modalities, more relevant models of this complex disease are being generated.


Asunto(s)
Animales Modificados Genéticamente/genética , Leucemia Mieloide Aguda/genética , Modelos Genéticos , Animales , Aberraciones Cromosómicas , Modelos Animales de Enfermedad , Exones , Humanos , Leucemia Mieloide Aguda/patología , Leucemia Promielocítica Aguda/genética , Ratones , Ratones Transgénicos , Pronóstico
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