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1.
Rev Sci Instrum ; 89(10): 10F111, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30399723

RESUMO

The paper reports on the optimization process of the soft X-ray pulse height analyzer installed on the Wendelstein 7-X (W7-X) stellarator. It is a 3-channel system that records X-ray spectra in the range from 0.6 to 19.6 keV. X-ray spectra, with a temporal and spatial resolution of 100 ms and 2.5 cm (depending on selected slit sizes), respectively, are line integrated along a line-of-sight that crosses near to the plasma center. In the second W7-X operation phase with a carbon test divertor unit, light impurities, e.g., carbon and oxygen, were observed as well as mid- to high-Z elements, e.g., sulfur, chlorine, chromium, manganese, iron, and nickel. In addition, X-ray lines from several tracer elements have been observed after the laser blow-off injection of different impurities, e.g., silicon, titanium, and iron, and during discharges with prefill or a gas puff of neon or argon. These measurements were achieved by optimizing light absorber-foil selection, which defines the detected energy range, and remotely controlled pinhole size, which defines photon flux. The identification of X-ray lines was confirmed by other spectroscopic diagnostics, e.g., by the High-Efficiency XUV Overview Spectrometer, HEXOS, and high-resolution X-ray imaging spectrometer, HR-XIS.

2.
Rev Sci Instrum ; 87(11): 11D304, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27910389

RESUMO

Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters in December 2015. At the end of the 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were in operation, allowing detailed studies of many interesting plasma phenomena. For example, fast neutral gas manometers supported by video cameras (including one fast-frame camera with frame rates of tens of kHz) as well as visible cameras with different interference filters, with field of views covering all ten half-modules of the stellarator, discovered a MARFE-like radiation zone on the inboard side of machine module 4. This structure is presumably triggered by an inadvertent plasma-wall interaction in module 4 resulting in a high impurity influx that terminates some discharges by radiation cooling. The main plasma parameters achieved in OP1.1 exceeded predicted values in discharges of a length reaching 6 s. Although OP1.1 is characterized by short pulses, many of the diagnostics are already designed for quasi-steady state operation of 30 min discharges heated at 10 MW of ECRH. An overview of diagnostic performance for OP1.1 is given, including some highlights from the physics campaigns.

3.
Oncogene ; 35(13): 1643-56, 2016 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-26165839

RESUMO

Resistance to therapies targeting the estrogen pathway remains a challenge in the treatment of estrogen receptor-positive breast cancer. To address this challenge, a systems biology approach was used. A library of small interfering RNAs targeting an estrogen receptor (ER)- and aromatase-centered network identified 46 genes that are dispensable in estrogen-dependent MCF7 cells, but are selectively required for the survival of estrogen-independent MCF7-derived cells and multiple additional estrogen-independent breast cancer cell lines. Integration of this information identified a tumor suppressor gene TOB1 as a critical determinant of estrogen-independent ER-positive breast cell survival. Depletion of TOB1 selectively promoted G1 phase arrest and sensitivity to AKT and mammalian target of rapmycin (mTOR) inhibitors in estrogen-independent cells but not in estrogen-dependent cells. Phosphoproteomic profiles from reverse-phase protein array analysis supported by mRNA profiling identified a significant signaling network reprogramming by TOB1 that differed in estrogen-sensitive and estrogen-resistant cell lines. These data support a novel function for TOB1 in mediating survival of estrogen-independent breast cancers. These studies also provide evidence for combining TOB1 inhibition and AKT/mTOR inhibition as a therapeutic strategy, with potential translational significance for the management of patients with ER-positive breast cancers.


Assuntos
Neoplasias da Mama/patologia , Proliferação de Células/genética , Resistencia a Medicamentos Antineoplásicos/genética , Estrogênios/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Supressoras de Tumor/genética , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Células MCF-7 , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Proteínas Supressoras de Tumor/metabolismo
4.
Rev Sci Instrum ; 85(11): 11D818, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25430231

RESUMO

An overview of the diagnostics which are essential for the first operational phase of Wendelstein 7-X and the set of diagnostics expected to be ready for operation at this time are presented. The ongoing investigations of how to cope with high levels of stray Electron Cyclotron Resonance Heating (ECRH) radiation in the ultraviolet (UV)/visible/infrared (IR) optical diagnostics are described.

5.
Brain Res ; 1576: 63-72, 2014 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-24976583

RESUMO

We report activation of the immediate-early gene Egr-1 in the lateral amygdala (LA), hippocampus (CA1), and medial prefrontal cortex (mPFC) 30-min following the training phase in the context pre-exposure facilitation effect (CPFE) and standard context fear conditioning (180 s context exposure→shock). On day one of the CPFE paradigm, postnatal day (PD) 31 rats (±1) were pre-exposed to Context A (Pre) or Context B (Alt-Pre) for 5 min followed by five additional 1-min exposures. A day later, Pre and Alt-Pre rats received a 2-s, 1.5 mA footshock immediately upon placement in Context A. Animals included in in situ hybridization were then sacrificed 30 (±3) min later. On day three, the behaviorally-tested Pre rats showed significantly more fear-conditioned freezing in Context A than Alt-Pre rats. Standard context fear conditioning groups showed much greater freezing than the Pre group, as well as no shock and immediate-shock controls. Thirty minutes after immediate shock training, Pre rats showed increased Egr-1 mRNA in the prelimbic mPFC relative to Alt-Pre rats. Standard context conditioning selectively increased Egr-1 in CA1. In the LA and mPFC, Egr-1 increased to a similar extent in no shock, immediate shock, and standard context conditioning relative to homecage controls. The present study demonstrates that Egr-1 mRNA expression has a complex relationship to fear learning in different brain regions and variants of context conditioning.


Assuntos
Tonsila do Cerebelo/metabolismo , Condicionamento Clássico/fisiologia , Proteína 1 de Resposta de Crescimento Precoce/genética , Medo/fisiologia , Reação de Congelamento Cataléptica/fisiologia , Genes Precoces , Hipocampo/metabolismo , Proteínas do Tecido Nervoso/genética , Córtex Pré-Frontal/metabolismo , RNA Mensageiro/biossíntese , Fatores Etários , Tonsila do Cerebelo/fisiologia , Animais , Proteína 1 de Resposta de Crescimento Precoce/biossíntese , Proteína 1 de Resposta de Crescimento Precoce/fisiologia , Eletrochoque , Feminino , Manobra Psicológica , Hipocampo/fisiologia , Masculino , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/fisiologia , Plasticidade Neuronal , Córtex Pré-Frontal/fisiologia , RNA Mensageiro/genética , Ratos , Ratos Long-Evans , Fatores de Tempo
6.
Neuroscience ; 265: 274-90, 2014 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-24513389

RESUMO

Neonatal alcohol exposure impairs cognition and learning in adulthood and permanently damages the hippocampus. Wheel running (WR) improves hippocampus-associated learning and memory and increases the genesis and survival of newly generated neurons in the hippocampal dentate gyrus. WR significantly increases proliferation of newly generated dentate granule cells in alcohol-exposed (AE) and control rats on Postnatal Day (PD) 42 but only control rats show an increased number of surviving cells thirty days after WR (Helfer et al., 2009b). The present studies examined whether proliferation-promoting WR followed by survival-enhancing environmental complexity (EC) during adolescence could increase survival of new neurons in AE rats. On PD 4-9, pups were intubated with alcohol in a binge-like manner (5.25g/kg/day, AE), were sham-intubated (SI), or were reared normally (suckle control, SC). On PD 30 animals were assigned to WR (PD 30-42) followed by EC (PD 42-72; WR/EC) or were socially housed (SH/SH) for the duration of the experiment. All animals were injected with 200mg/kg bromodeoxyuridine (BrdU) on PD 41. In Experiment 1, survival of newly generated cells was significantly enhanced in the AE-WR/EC group in comparison with AE-SH/SH group. Experiment 2A examined trace eyeblink conditioning. In the SH/SH condition, AE impaired trace eyeblink conditioning relative to SI and SC controls. In the WR/EC condition, AE rats performed as well as controls. In Experiment 2B, the same intervention was examined using the context preexposure facilitation effect (CPFE); a hippocampus-dependent variant of contextual fear conditioning. Again, the WR/EC intervention reversed the deficit in conditioned fear to the context that was evident in the SH/SH condition. Post-weaning environmental manipulations promote cell survival and reverse learning deficits in rats that were exposed to alcohol during development. These manipulations may provide a basis for developing interventions that ameliorate learning impairments associated with human fetal alcohol spectrum disorders.


Assuntos
Meio Ambiente , Etanol/toxicidade , Terapia por Exercício , Hipocampo/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Condicionamento Clássico/efeitos dos fármacos , Condicionamento Palpebral/efeitos dos fármacos , Medo/fisiologia , Feminino , Hipocampo/crescimento & desenvolvimento , Hipocampo/fisiologia , Atividade Motora , Gravidez , Ratos , Ratos Long-Evans
7.
Alcohol ; 48(1): 35-42, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24387902

RESUMO

Alcohol exposure on postnatal days (PND) 4-9 in the rat adversely affects hippocampal anatomy and function and impairs performance on a variety of hippocampus-dependent tasks. Exposure during this developmental window reveals a linear relationship between alcohol dose and spatial learning impairment in the context preexposure facilitation effect (CPFE), a hippocampus-dependent variant of contextual fear conditioning. The purpose of the current report was to examine the effect of a range of alcohol doses administered during a narrower window, PND7-9, than previously reported (Experiment 1) and to begin to determine which memory processes involved in this task are impaired by developmental alcohol exposure (Experiment 2). In Experiment 1, rats pups received a single day binge alcohol dose of either 2.75, 4.00, 5.25 g/kg/day or were sham-intubated (SI) from PND7-9. Conditioned freezing during the test day was evident in all dosing groups, except for Group 5.25 g, indicating no graded dose-related behavioral deficits with alcohol exposure limited to PND7-9. In Experiment 2, rat pups were exposed to the highest effective dose from Experiment 1 (5.25 g/kg/day) or were sham intubated over PND7-9. During training, rats remained in the conditioning context for 5-min following immediate shock delivery. During this test of post-shock freezing, both SI and alcohol-exposed rats given prior exposure to the conditioning context showed comparable freezing levels. Since alcohol-exposed rats showed normal post-shock freezing, deficits by these rats on the test day likely reflect a failure to consolidate or retrieve a context-shock association, rather than a deficit in hippocampal conjunctive processes (consolidation, pattern completion) that occur prior to shock on the training day. These findings illustrate the value of the CPFE for characterizing the separable memory processes that are impaired by neonatal alcohol exposure in this task.


Assuntos
Condicionamento Psicológico/efeitos dos fármacos , Etanol/toxicidade , Medo/efeitos dos fármacos , Memória/efeitos dos fármacos , Envelhecimento , Animais , Animais Recém-Nascidos , Peso Corporal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Etanol/sangue , Feminino , Masculino , Ratos , Ratos Long-Evans
8.
Behav Brain Res ; 256: 140-50, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-23933466

RESUMO

In the novel object recognition (OR) paradigm, rats are placed in an arena where they encounter two sample objects during a familiarization phase. A few minutes later, they are returned to the same arena and are presented with a familiar object and a novel object. The object location recognition (OL) variant involves the same familiarization procedure but during testing one of the familiar objects is placed in a novel location. Normal adult rats are able to perform both the OR and OL tasks, as indicated by enhanced exploration of the novel vs. the familiar test item. Rats with hippocampal lesions perform the OR but not OL task indicating a role of spatial memory in OL. Recently, these tasks have been used to study the ontogeny of spatial memory but the literature has yielded conflicting results. The current experiments add to this literature by: (1) behaviorally characterizing these paradigms in postnatal day (PD) 21, 26 and 31-day-old rats; (2) examining the role of NMDA systems in OR vs. OL; and (3) investigating the effects of neonatal alcohol exposure on both tasks. Results indicate that normal-developing rats are able to perform OR and OL by PD21, with greater novelty exploration in the OR task at each age. Second, memory acquisition in the OL but not OR task requires NMDA receptor function in juvenile rats [corrected]. Lastly, neonatal alcohol exposure does not disrupt performance in either task. Implications for the ontogeny of incidental spatial learning and its disruption by developmental alcohol exposure are discussed.


Assuntos
Envelhecimento/efeitos dos fármacos , Envelhecimento/psicologia , Depressores do Sistema Nervoso Central/farmacologia , Etanol/farmacologia , Reconhecimento Psicológico/fisiologia , Percepção Espacial/fisiologia , Análise de Variância , Animais , Depressores do Sistema Nervoso Central/sangue , Etanol/sangue , Comportamento Exploratório/efeitos dos fármacos , Comportamento Exploratório/fisiologia , Feminino , Masculino , Testes Neuropsicológicos , Ratos Long-Evans , Receptores de N-Metil-D-Aspartato/metabolismo , Reconhecimento Psicológico/efeitos dos fármacos , Percepção Espacial/efeitos dos fármacos
9.
Dev Psychobiol ; 55(5): 483-95, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22644967

RESUMO

In rodents, voluntary exercise and environmental complexity increases hippocampal neurogenesis and reverses spatial learning and long-term potentiation deficits in animals prenatally exposed to alcohol. The present experiment extended these findings to neonatal alcohol exposure and to delay, trace, and contextual fear conditioning. Rats were administered either 5.25 g/kg/day alcohol via gastric intubation or received sham-intubations (SI) between Postnatal Day (PD) 4 and 9 followed by either free access to a running wheel on PD 30-41 and housing in a complex environment on PD 42-72 (wheel-running plus environmental complexity; WREC) or conventional social housing (SHSH) from PD 30 to 72. Adult rats (PD 80 ± 5) received 5 trials/day of a 10-s flashing-light conditioned stimulus (CS) paired with .8 mA footshock either immediately (delay conditioning) or after a 10-s trace interval (trace conditioning) for 2 days. Neonatal alcohol exposure impaired context and trace conditioning, but not short-delay conditioning. The WREC intervention did not reverse these deficits, despite increasing context-related freezing in ethanol-exposed and SI animals.


Assuntos
Condicionamento Psicológico/efeitos dos fármacos , Meio Ambiente , Etanol/farmacologia , Medo/efeitos dos fármacos , Condicionamento Físico Animal/fisiologia , Animais , Animais Recém-Nascidos , Condicionamento Psicológico/fisiologia , Modelos Animais de Doenças , Medo/fisiologia , Feminino , Transtornos do Espectro Alcoólico Fetal , Reação de Congelamento Cataléptica/efeitos dos fármacos , Reação de Congelamento Cataléptica/fisiologia , Abrigo para Animais , Ratos
10.
Rev Sci Instrum ; 83(2): 02B105, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22380262

RESUMO

This contribution reports particle-in-cell numerical studies of deuteron beam acceleration by a picosecond laser pulse of circular polarization. The effect of laser wavelength λ and the I(L)λ(2) product (I(L) is laser intensity) on the ion beam parameters is investigated. It is shown that at the I(L)λ(2) product fixed, the beam parameters (, I(i), F(i)) as well as the laser-ions energy conversion efficiency quickly increase with a decrease in the laser wavelength and the best results are achieved for a KrF laser (λ = 0.248 µm). In particular, a 2-ps KrF laser pulse of I(L)λ(2) ∼ 2 × 10(20) Wcm(-2) µm(2) interacting with a 10-µm deuteron target produces a quasi-monoenergetic, solid-density deuteron beam of parameters approaching those required for inertial confinement fusion fast ignition.

11.
Nutr Hosp ; 26(5): 1025-32, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22072348

RESUMO

INTRODUCTION: The aim of this study was to assess non-microcellular lung cancer patients´ nutritional status impact on psychomotor performance, muscle strength and functional activity. MATERIAL AND METHODS: The study involved 60 consecutive patients admitted to the clinic for surgical treatment due to histologically verified non-microcellular lung cancer. The patients were divided, depending on the stage of weight loss, into two groups: relatively well-nourished--29 patients and those with malnutrition--31 patients. History, physical examination, anthropometric data, biochemical parameters as well as functional tests were carefully noted. RESULTS: Patients qualified for particular groups differed significantly in age, p<0.002. Mean values of albumin, transferrin and total protein for the well nourished patients ranged within proper values. In the malnourished patients they were respectively: 34.05±0.27 g/l, 1.764±0.27 g/l, 68.90±6.39 g/l and the differences were statistically significant. Total loss of urea nitrogen was significantly higher in malnourished patients 13.32±2.92 g/l (p<0.005). The average percentage weight loss in both groups differed significantly 0.111±0.044 vs. 0.031±0.028 at p<0.0005. In the group of malnourished patients the right hand average strength was 26.52±8.06 kg and the left one amounted to 25.35±6.04 kg, The values were significantly lower than the results recorded in well nourished patients: 34.93±11.27 kg, 32,37±11.72 kg, p<0.001. The tapping test average time of the right hand was 19.24±4.04 vs. 16.72±3.06 and of the left one 19.69±3.59 kg vs. 17.48±2.79 kg and were significantly longer in patients suffering from malnutrition (p<0.01). Simple reaction times for dominating hand were longer in the group of patients with malnutrition, for the visual stimulus 0.50±0.08 s vs. 0.45±0.087 s, (p<0.05) and for auditory one 0.43±0.08 vs. 0.39±0.08 s (non significant). CONCLUSIONS: Malnutrition in the course of non-microcellular lung cancer significantly reduces psychomotor function assessed by reaction time to visual and acoustic stimuli as well as efficiency of the functional tests evaluated by tapping test and muscle strength measurement.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/metabolismo , Desnutrição/diagnóstico , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Contagem de Células Sanguíneas , Estatura/fisiologia , Índice de Massa Corporal , Peso Corporal/fisiologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/cirurgia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/cirurgia , Masculino , Desnutrição/fisiopatologia , Pessoa de Meia-Idade , Força Muscular/fisiologia , Estado Nutricional , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia
12.
Brain Res ; 1412: 88-101, 2011 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-21816390

RESUMO

Developmental alcohol exposure can permanently alter brain structures and produce functional impairments in many aspects of behavior, including learning and memory. This study evaluates the effect of neonatal alcohol exposure on adult neurogenesis in the dentate gyrus of the hippocampus and the implications of such exposure for hippocampus-dependent contextual fear conditioning. Alcohol-exposed rats (AE) received 5.25g/kg/day of alcohol on postnatal days (PD) 4-9 (third trimester in humans), in a binge-like manner. Two control groups were included: sham-intubated (SI) and suckle-control (SC). Animals were housed in social cages (3/cage) after weaning. On PD80, animals were injected with 200mg/kg BrdU. Half of the animals were sacrificed 2h later. The remainder were sacrificed on PD114 to evaluate cell survival; separate AE, SI, and SC rats not injected with BrdU were tested for the context preexposure facilitation effect (CPFE; ~PD117). There was no difference in the number of BrdU+ cells in AE, SI and SC groups on PD80. On PD114, cell survival was significantly decreased in AE rats, demonstrating that developmental alcohol exposure damages new cells' ability to incorporate into the network and survive. Behaviorally tested SC and SI groups preexposed to the training context 24h prior to receiving a 1.5mA 2s footshock froze significantly more during the context test than their counterparts preexposed to an alternate context. AE rats failed to show the CPFE. The current study shows the detrimental, long-lasting effects of developmental alcohol exposure on hippocampal adult neurogenesis and contextual fear conditioning.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Condicionamento Psicológico/efeitos dos fármacos , Etanol/farmacologia , Medo/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Proliferação de Células , Feminino , Hipocampo/crescimento & desenvolvimento , Masculino , Neurônios/efeitos dos fármacos , Ratos , Ratos Long-Evans
13.
Methods Inf Med ; 45(4): 359-66, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16964350

RESUMO

OBJECTIVES: The exchange of medical data from research and clinical routine across institutional borders is essential to establish an integrated healthcare platform. In this project we want to realize the standardized exchange of medical data between different healthcare institutions to implement an integrated and interoperable information system supporting clinical treatment and research of glaucoma. METHODS: The central point of our concept is a standardized communication model based on the Clinical Document Architecture (CDA). Further, a communication concept between different health care institutions applying the developed document model has been defined. RESULTS: With our project we have been able to prove that standardized communication between an Electronic Medical Record (EMR), an Electronic Health Record (EHR) and the Erlanger Glaucoma Register (EGR) based on the established conceptual models, which rely on CDA rel.1 level 1 and SCIPHOX, could be implemented. The HL7-tool-based deduction of a suitable CDA rel.2 compliant schema showed significant differences when compared with the manually created schema. Finally fundamental requirements, which have to be implemented for an integrated health care platform, have been identified. CONCLUSIONS: An interoperable information system can enhance both clinical treatment and research projects. By automatically transferring screening findings from a glaucoma research project to the electronic medical record of our ophthalmology clinic, clinicians could benefit from the availability of a longitudinal patient record. The CDA as a standard for exchanging clinical documents has demonstrated its potential to enhance interoperability within a future shared care paradigm.


Assuntos
Redes de Comunicação de Computadores/normas , Prestação Integrada de Cuidados de Saúde/organização & administração , Glaucoma/terapia , Registro Médico Coordenado , Sistemas Computadorizados de Registros Médicos/normas , Oftalmologia/organização & administração , Semântica , Integração de Sistemas , Sistemas de Gerenciamento de Base de Dados , Alemanha , Humanos , Linguagens de Programação , Pesquisa
14.
Oncogene ; 25(44): 5960-8, 2006 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-16652148

RESUMO

The neurofibromatosis type 2 NF2 gene product, merlin, is a tumor suppressor frequently inactivated in malignant mesothelioma (MM). To investigate a possible correlation between merlin inactivation and MM invasiveness, we restored merlin expression in NF2-deficient MM cells. Re-expression of merlin markedly inhibited cell motility, spreading and invasiveness, properties connected with the malignant phenotype of MM cells. To test directly whether merlin inactivation promotes invasion in a nonmalignant system, we used small interfering RNA to silence Nf2 in mouse embryonic fibroblasts (MEFs) and found that downregulation of merlin resulted in enhanced cell spreading and invasion. To delineate signaling events connected with this phenotype, we investigated the effect of merlin expression on focal adhesion kinase (FAK), a key component of cellular pathways affecting migration and invasion. Expression of merlin attenuated FAK phosphorylation at the critical phosphorylation site Tyr397 and disrupted the interaction of FAK with its binding partners Src and p85, the regulatory subunit of phosphatidylinositol-3-kinase. In addition, NF2-null MM cells stably overexpressing FAK showed increased invasiveness, which decreased significantly when merlin expression was restored. Collectively, these findings suggest that merlin inactivation is a critical step in MM pathogenesis and is related, at least in part, with upregulation of FAK activity.


Assuntos
Proteína-Tirosina Quinases de Adesão Focal/antagonistas & inibidores , Mesotelioma/patologia , Mesotelioma/prevenção & controle , Neurofibromina 2/biossíntese , Neurofibromina 2/genética , Animais , Linhagem Celular Tumoral , Inibição de Migração Celular , Células Cultivadas , Regulação para Baixo/genética , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Proteína-Tirosina Quinases de Adesão Focal/fisiologia , Humanos , Mesotelioma/enzimologia , Camundongos , Invasividade Neoplásica/prevenção & controle , Neurofibromina 2/fisiologia , Transdução de Sinais/genética
15.
Cancer Biol Ther ; 2(3): 236-41, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12878855

RESUMO

Microtubule poisons such as taxol and vinblastine are widely used to treat a variety of cancers. These drugs are believed to kill cells by blocking mitosis. However, there is a critical need to identify new drugs because tumors can often become refractory to treatment with existing drugs. Studies over the past decade on chromosome segregation have uncovered a plethora of novel proteins that function specifically in mitosis. Centrosomes and kinetochores are two organelles that specify formation of the spindle and the attachment of chromosomes to the spindle, respectively. The focus of this review is to highlight the kinetochore as a rich source of targets for the development of mitosis-specific drugs.


Assuntos
Antineoplásicos/farmacologia , Cinetocoros/efeitos dos fármacos , Proteínas Associadas aos Microtúbulos/antagonistas & inibidores , Mitose/efeitos dos fármacos , Animais , Centrossomo/efeitos dos fármacos , Humanos , Fuso Acromático/efeitos dos fármacos
16.
Phys Rev Lett ; 87(21): 215001, 2001 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-11736343

RESUMO

The results of studies of fast-proton generation from foil targets irradiated by 1-ps laser pulse at 10(17) W/cm (2) are presented. It is shown that a considerable increase in proton energy and current is possible when a double-layer foil target containing a high- Z layer and a low- Z hydrogen-rich layer is used instead of a single-layer target. Proton energies and current increase with the Z of the high- Z layer and depend essentially on the target and the layer thicknesses. Above 10(9) forward-emitted protons of energy >100 keV have been recorded within a cone angle <3 degrees.

17.
J Biol Chem ; 276(28): 26559-67, 2001 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-11352911

RESUMO

The mRNA export factor RAE1 (also called GLE2) and the mitotic checkpoint protein BUB3 share extensive sequence homology in yeast as well as higher eukaryotes, although the biological relevance of their similarity is unclear. Previous work in HeLa cells has shown that human (h)RAE1 binds the nuclear pore complex protein hNUP98 via a short NUP98 motif called GLEBS (for GLE2p-binding sequence). Here we report that the two known binding partners of hBUB3, the mitotic checkpoint proteins hBUB1 and hBUBR1, both carry a region with remarkable similarity to the GLEBS motif of hNUP98. We show that the GLEBS-like motifs of mouse (m)BUB1 and mBUBR1 are sufficient for mBUB3 binding. mBUB3 lacks affinity for the hNUP98 GLEBS, demonstrating its binding specificity for GLEBS motifs of mitotic checkpoint proteins. Interestingly, mRAE1 does not exclusively bind to the GLEBS motif of hNUP98 and can cross-interact with the mBUB1 GLEBS. We show that full-length RAE1 and BUB1 proteins interact in mammalian cells and accumulate both at the kinetochores of prometaphase chromosomes. Our findings demonstrate that GLEBS motifs reside in mammalian nucleoporins and mitotic checkpoint proteins and apparently serve as specific binding sites for either BUB3, RAE1, or both.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular , Proteínas Associadas à Matriz Nuclear , Proteínas Nucleares/metabolismo , Proteínas de Transporte Nucleocitoplasmático , Proteínas/metabolismo , Proteínas de Schizosaccharomyces pombe , Células 3T3 , Sequência de Aminoácidos , Animais , Sítios de Ligação , Proteínas Cromossômicas não Histona , Células HeLa , Humanos , Camundongos , Mitose , Dados de Sequência Molecular , Proteínas de Ligação a Poli-ADP-Ribose , Ligação Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Transdução de Sinais
18.
Nat Cell Biol ; 2(12): 944-7, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11146660

RESUMO

Here we show that human Zeste White 10 (Zw10) and Rough deal (Rod) are new components of the mitotic checkpoint, as cells lacking these proteins at kinetochores fail to arrest in mitosis when exposed to microtubule inhibitors. Checkpoint failure and premature mitotic exit may explain why cells defective for hZw10 and hRod divide with lagging chromosomes. As Zw10 and Rod are not conserved in yeast, our data, combined with an accompanying study of Drosophila Zw10 and Rod, indicate that metazoans may require an elaborate spindle checkpoint to monitor complex kinetochore functions.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Cinetocoros/metabolismo , Mitose/fisiologia , Sítios de Ligação , Proteínas Cromossômicas não Histona/metabolismo , Células HeLa , Humanos , Microscopia de Fluorescência , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Nocodazol/farmacologia , Ligação Proteica , Fuso Acromático/metabolismo
20.
J Cell Biol ; 146(5): 941-54, 1999 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-10477750

RESUMO

Human cells express two kinases that are related to the yeast mitotic checkpoint kinase BUB1. hBUB1 and hBUBR1 bind to kinetochores where they are postulated to be components of the mitotic checkpoint that monitors kinetochore activities to determine if chromosomes have achieved alignment at the spindle equator (Jablonski, S.A., G.K.T. Chan, C.A. Cooke, W.C. Earnshaw, and T.J. Yen. 1998. Chromosoma. 107:386-396). In support of this, hBUB1 and the homologous mouse BUB1 have been shown to be important for the mitotic checkpoint (Cahill, D.P., C. Lengauer, J. Yu, G.J. Riggins, J.K. Willson, S.D. Markowitz, K.W. Kinzler, and B. Vogelstein. 1998. Nature. 392:300-303; Taylor, S.S., and F. McKeon. 1997. Cell. 89:727-735). We now demonstrate that hBUBR1 is also an essential component of the mitotic checkpoint. hBUBR1 is required by cells that are exposed to microtubule inhibitors to arrest in mitosis. Additionally, hBUBR1 is essential for normal mitotic progression as it prevents cells from prematurely entering anaphase. We establish that one of hBUBR1's checkpoint functions is to monitor kinetochore activities that depend on the kinetochore motor CENP-E. hBUBR1 is expressed throughout the cell cycle, but its kinase activity is detected after cells have entered mitosis. hBUBR1 kinase activity was rapidly stimulated when the spindle was disrupted in mitotic cells. Finally, hBUBR1 was associated with the cyclosome/anaphase-promoting complex (APC) in mitotically arrested cells but not in interphase cells. The combined data indicate that hBUBR1 can potentially provide two checkpoint functions by monitoring CENP-E-dependent activities at the kinetochore and regulating cyclosome/APC activity.


Assuntos
Proteínas Cromossômicas não Histona/metabolismo , Cinetocoros/metabolismo , Ligases/metabolismo , Mitose , Proteínas Quinases/metabolismo , Complexos Ubiquitina-Proteína Ligase , Anáfase/efeitos dos fármacos , Ciclossomo-Complexo Promotor de Anáfase , Apoptose , Proteínas de Ciclo Celular , Cromossomos Humanos/efeitos dos fármacos , Cromossomos Humanos/genética , Cromossomos Humanos/metabolismo , Ativação Enzimática/efeitos dos fármacos , Expressão Gênica , Células HeLa , Humanos , Células K562 , Cinetocoros/efeitos dos fármacos , Metáfase/efeitos dos fármacos , Mitose/efeitos dos fármacos , Nocodazol/farmacologia , Fosforilação , Testes de Precipitina , Ligação Proteica , Proteínas Quinases/genética , Proteínas Serina-Treonina Quinases , Deleção de Sequência , Fuso Acromático/efeitos dos fármacos , Fuso Acromático/metabolismo , Ubiquitina-Proteína Ligases
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