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1.
Appl Opt ; 59(14): 4271-4278, 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32400400

RESUMO

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.
Gene ; 699: 110-114, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30844479

RESUMO

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.


Assuntos
Diarreia Infantil/diagnóstico , Diarreia Infantil/genética , Diarreia/diagnóstico , Diarreia/genética , Retardo do Crescimento Fetal/diagnóstico , Retardo do Crescimento Fetal/genética , Doenças do Cabelo/diagnóstico , Doenças do Cabelo/genética , DNA Helicases/genética , Fácies , Heterozigoto , Humanos
3.
J Chem Phys ; 147(22): 224303, 2017 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-29246058

RESUMO

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.

4.
J Chem Phys ; 145(2): 024306, 2016 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-27421404

RESUMO

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.

5.
J Chem Phys ; 144(1): 014307, 2016 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-26747806

RESUMO

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.

6.
Cancer Gene Ther ; 21(11): 457-62, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25277132

RESUMO

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.


Assuntos
Artéria Hepática/metabolismo , Imunoterapia/métodos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/secundário , Receptores de Antígenos de Linfócitos T/uso terapêutico , Proteínas Recombinantes de Fusão/uso terapêutico , Biomarcadores Tumorais/sangue , Contagem de Células Sanguíneas , Citocinas/sangue , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Infusões Intra-Arteriais/métodos , Interleucina-17/sangue , Interleucina-6/sangue , Linfócitos/citologia , Masculino , Pessoa de Meia-Idade , Neutrófilos/citologia , Prognóstico
7.
Br J Radiol ; 87(1044): 20140239, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25270608

RESUMO

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.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Mamografia/métodos , Mastectomia/métodos , Tumor Filoide/diagnóstico por imagem , Adolescente , Adulto , Neoplasias da Mama/cirurgia , Registros Eletrônicos de Saúde , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Tumor Filoide/cirurgia , Prognóstico , Estudos Retrospectivos , Adulto Jovem
8.
Cell Death Dis ; 4: e516, 2013 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-23449452

RESUMO

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.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , AMP Cíclico/metabolismo , Daunorrubicina/farmacologia , 1-Metil-3-Isobutilxantina/farmacologia , Animais , Antibióticos Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , AMP Cíclico/agonistas , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Proteína Quinase Tipo I Dependente de AMP Cíclico/metabolismo , Proteína Quinase Tipo II Dependente de AMP Cíclico/antagonistas & inibidores , Proteína Quinase Tipo II Dependente de AMP Cíclico/genética , Proteína Quinase Tipo II Dependente de AMP Cíclico/metabolismo , Daunorrubicina/uso terapêutico , Dinoprostona/análogos & derivados , Dinoprostona/farmacologia , Dinoprostona/uso terapêutico , Progressão da Doença , Células HL-60 , Humanos , Leucemia Promielocítica Aguda/tratamento farmacológico , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologia , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Teofilina/farmacologia , Teofilina/uso terapêutico , Transplante Heterólogo , Tretinoína/farmacologia , Tretinoína/uso terapêutico , Proteína de Morte Celular Associada a bcl/metabolismo
9.
J Chem Phys ; 137(3): 034306, 2012 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-22830701

RESUMO

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.

10.
Leukemia ; 26(5): 910-7, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22064349

RESUMO

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.


Assuntos
Apoptose/efeitos dos fármacos , Genes p53 , Imidazóis/farmacologia , Leucemia Mieloide Aguda/patologia , Piperazinas/farmacologia , Ácido Valproico/farmacologia , Acetilação , Animais , Antígenos CD34/metabolismo , Apoptose/genética , Linhagem Celular Tumoral , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores de Histona Desacetilases/farmacologia , Humanos , Leucemia Mieloide Aguda/genética , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Microscopia Eletrônica de Transmissão , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores
11.
Opt Lett ; 36(24): 4725-7, 2011 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-22179863

RESUMO

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.

12.
Neuropathol Appl Neurobiol ; 37(2): 189-205, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20819169

RESUMO

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.


Assuntos
Neoplasias Encefálicas/secundário , Modelos Animais de Doenças , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Dosagem de Genes , Humanos , Imuno-Histoquímica , Microscopia Confocal , Análise de Sequência com Séries de Oligonucleotídeos , Ratos , Análise Serial de Tecidos , Células Tumorais Cultivadas
13.
J Phys Chem A ; 114(42): 11175-88, 2010 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-20593817

RESUMO

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.


Assuntos
Ouro/química , Hidrogênio/química , Teoria Quântica , Propriedades de Superfície
14.
Transplant Proc ; 41(9): 3863-7, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19917402

RESUMO

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.


Assuntos
Melfalan/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/cirurgia , Antineoplásicos Alquilantes/administração & dosagem , Antineoplásicos Alquilantes/uso terapêutico , Terapia Combinada , Progressão da Doença , Esquema de Medicação , Humanos , Melfalan/administração & dosagem , Mieloma Múltiplo/mortalidade , Mieloma Múltiplo/patologia , Estadiamento de Neoplasias , Transplante de Células-Tronco , Transplante Autólogo
15.
FEBS Lett ; 583(4): 782-6, 2009 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-19183552

RESUMO

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.


Assuntos
Actinas/química , Actinas/metabolismo , Aminoácidos/metabolismo , Chaperoninas/química , Chaperoninas/metabolismo , Actinas/genética , Actinas/isolamento & purificação , Actinas/ultraestrutura , Sequência de Aminoácidos , Animais , Asparagina/metabolismo , Chaperonina com TCP-1 , Chaperoninas/genética , Chaperoninas/isolamento & purificação , Chaperoninas/ultraestrutura , Escherichia coli/genética , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Músculo Esquelético/química , Mutação , Conformação Proteica , Dobramento de Proteína , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Coelhos , Saccharomyces cerevisiae/metabolismo , Homologia de Sequência de Aminoácidos , Termodinâmica
16.
Oncogene ; 27(27): 3765-79, 2008 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-18264136

RESUMO

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.


Assuntos
Animais Geneticamente Modificados/genética , Leucemia Mieloide Aguda/genética , Modelos Genéticos , Animais , Aberrações Cromossômicas , Modelos Animais de Doenças , Éxons , Humanos , Leucemia Mieloide Aguda/patologia , Leucemia Promielocítica Aguda/genética , Camundongos , Camundongos Transgênicos , Prognóstico
17.
J Chem Phys ; 126(18): 184702, 2007 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-17508819

RESUMO

The ionization of a beam of H2 Rydberg molecules in collision with a metal surface (evaporated Au or Al) is studied. The Rydberg states are excited in an ultraviolet-vacuum ultraviolet double-resonant process and are state selected with a core rotational quantum number N+=0 or 2 and principal quantum numbers n=17-22 (N+=2) or n=41-45 (N+=0). It is found that the N+=0 states behave in a very similar manner to previous studies with atomic xenon Rydberg states, the distance of ionization from the surface scaling with n2. The N+=2 states, however, undergo a process of surface-induced rotational autoionization in which the core rotational energy transfers to the Rydberg electron. In this case the ionization distance scales approximately with nu0(2), the effective principal quantum number with respect to the adiabatic threshold. This process illustrates the close similarity between field ionization in the gas phase and the surface ionization process which is induced by the field due to image charges in the metal surface. The surface ionization rate is enhanced at certain specific values of the field, which is applied in the time interval between excitation and surface interaction. It is proposed here that these fields correspond to level crossings between the N+=0 and N+=2 Stark manifolds. The population of individual states of the N+=2, n=18 Stark manifold in the presence of a field shows that the surface-induced rotational autoionization is more facile for the blueshifted states, whose wave function is oriented away from the surface, than for the redshifted states. The observed processes appear to show little dependence on the chemical nature of the metallic surface, but a significant change occurs when the surface roughness becomes comparable to the Rydberg orbit dimensions.

18.
Leukemia ; 19(5): 687-706, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15759039

RESUMO

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.


Assuntos
Modelos Animais de Doenças , Leucemia Mieloide Aguda , Animais , Engenharia Genética , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/terapia , Transplante de Neoplasias , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Artigo em Inglês | MEDLINE | ID: mdl-17282177

RESUMO

We applied the concept of "phase synchronization" from nonlinear dynamics to the complex relationship between intracranial pressure (ICP) and arterial blood pressure (ABP) signals. This method is based on multiresolution wavelet transform (MRWT) in which the signals are divided into different frequency bands. We examined ICP and ABP signals from anaesthetized dogs, exploring normal ICP and elevated ICP by 1~3 ml injection of saline into the cerebral ventricles. Phase synchronization analyses show an interesting phenomenon of phase reset from relatively uniform phase distribution to phase clustering around 0° after injection. To further quantitatively measure phase synchronization, phase coherence is used to distinguish the dynamics of normal ICP and elevated ICP by saline injection. Elevated ICP exhibits higher phase coherence than that of normal ICP. The results suggest that the association between ICP and ABP may involve nonlinear mechanisms of regulation. The clinical application of this method is in investigation.

20.
J Struct Biol ; 135(2): 185-97, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11580268

RESUMO

The three-dimensional reconstruction of apo-CCT-alpha-actin by cryoelectron microscopy shows that actin binds either the CCTbeta-CCTdelta or the CCTepsilon-CCTdelta subunit pairs of the chaperonin in an open and apparently quasi-native conformation. The CCT-binding sites are seen located at the tips of the two arms of actin and these same regions of actin have been implicated in CCT binding through beta-actin peptide-array screening. Three main CCT binding regions exist: actin Sites I, II, and III, which are composed of loops that are surface-exposed in native actin. Sixty-eight amino acid residues on beta-actin have been screened by mutagenesis for effects on CCT interaction in quantitative in vitro translation assays in rabbit reticulocyte lysate. Actin seems to be folding cooperatively on chaperonin, since certain mutants discriminate CCT binding from processing. Actin Site II, located at the tip of actin subdomain 4, is the major determinant for CCT binding. Site II is composed of two anti-parallel extended beta-strands, with F200-T203 and D244 contributing substantially to the binding site. The substrate recognition chemistry of CCT thus seems different from that of Group I chaperonins and probably reflects the fact that it needs to be highly specific to enable capture and folding of the actins and tubulins.


Assuntos
Actinas/química , Chaperoninas/metabolismo , Proteínas do Citoesqueleto , Proteínas de Drosophila , Proteínas dos Microfilamentos , Mutagênese Sítio-Dirigida , Dobramento de Proteína , Actinas/genética , Actinas/metabolismo , Animais , Sítios de Ligação , Proteínas de Ciclo Celular , Sistema Livre de Células , Chaperonina com TCP-1 , Chaperoninas/química , Citosol , Células Eucarióticas , Humanos , Cinética , Camundongos , Ligação Proteica , Estrutura Terciária de Proteína , Especificidade por Substrato
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