RESUMO
To search for low-energy resonant structures in isospin T=3/2 three-body systems, we have performed the experiments ^{3}H(t,^{3}He)3n and ^{3}He(^{3}He,t)3p at intermediate energies. For the 3n experiment, we have newly developed a thick Ti-^{3}H target that has the largest tritium thickness among targets of this type ever made. The 3n experiment for the first time covered the momentum-transfer region as low as 15 MeV/c, which provides ideal conditions for producing fragile systems. However, in the excitation-energy spectra we obtained, we did not observe any distinct peak structures. This is in sharp contrast to tetraneutron spectra. The distributions of the 3n and 3p spectra are found to be similar, except for the displacement in energy due to Coulomb repulsion. Comparisons with theoretical calculations suggest that three-body correlations exist in the 3n and 3p systems, although not enough to produce a resonant peak.
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Chromosome damage combined with defective recombinase activity has been widely considered to render cells inviable, owing to deficient double-strand break repair. However, temperature-sensitive recAts polA cells grow well upon induction of DNA damage and supplementation with catalase at restrictive temperatures. These treatments reduce intracellular reactive oxygen species (ROS) levels, which suggests that recAts polA cells are susceptible to ROS, but not chronic chromosome damage. Therefore, we investigated whether polA cells can tolerate a complete lack of recombinase function. We introduced a ΔrecA allele in polA cells in the presence or absence of the hslO-encoding redox molecular chaperon Hsp33 expression plasmid. Induction of the hslO gene with IPTG resulted in increased cell viability in ΔrecA polA cells with the hslO expression plasmid. ΔrecA polA cells in the absence of the hslO expression plasmid showed rich medium sensitivity with increasing ROS levels. Adding catalase to the culture medium considerably rescued growth arrest and decreased ROS. These results suggest that hslO expression manages oxidative stress to an acceptable level in cells with oxidative damage and rescues cell growth. Overall, ROS may regulate several processes, from damage response to cell division, via ROS-sensitive cell metabolism.
Assuntos
Dano ao DNA , Estresse Oxidativo , Catalase/genética , Catalase/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Recombinases/metabolismoRESUMO
Although the introduction of tyrosine kinase inhibitors (TKIs) has improved overall survival of patients with chronic myeloid leukemia (CML), about half of the patients eventually relapse after cessation of TKIs. In contrast, the remainder of the patients maintain molecular remission without TKIs, indicating that the patients' immune system could control proliferation of TKI-resistant leukemic stem cells (LSCs). However, the precise mechanism of immunity against CML-LSCs is not fully understood. We have identified a novel immune target, CXorf48, expressed in LSCs of CML patients. Cytotoxic T cells (CTLs) induced by the epitope peptide derived from CXorf48 recognized CD34+CD38- cells obtained from the bone marrow of CML patients. We detected CXorf48-specific CTLs in the peripheral blood mononuclear cells from CML patients who have discontinued imatinib after maintaining complete molecular remission for more than 2 years. Significantly, the relapse rate of CXorf48-specific CTL-negative patients was 63.6%, compared to 0% in CXorf48-specific CTL-positive patients. These results indicate that CXorf48 could be a promising therapeutic target of LSCs for immunotherapy to obtain durable treatment-free remission in CML patients.
Assuntos
Células da Medula Óssea/imunologia , Linfócitos T CD8-Positivos/imunologia , Regulação Leucêmica da Expressão Gênica/imunologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/imunologia , Proteínas de Neoplasias/imunologia , Células-Tronco Neoplásicas/imunologia , Células da Medula Óssea/patologia , Linfócitos T CD8-Positivos/patologia , Feminino , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Humanos , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Masculino , Células-Tronco Neoplásicas/patologia , Células THP-1Assuntos
Alelos , Transtornos Plaquetários/complicações , Transtornos Plaquetários/genética , Transformação Celular Neoplásica/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Predisposição Genética para Doença , Haploinsuficiência , Leucemia Mieloide Aguda/etiologia , Adulto , Transtornos Plaquetários/diagnóstico , Feminino , Estudos de Associação Genética , Humanos , Leucemia Mieloide Aguda/diagnóstico , Masculino , Pessoa de Meia-Idade , LinhagemRESUMO
Post-transplant lymphoproliferative disorder (PTLD) is one of the life-threatening complications after hematopoietic stem cell transplantation (HSCT) and solid organ transplantation (SOT), and it is associated almost exclusively with Epstein-Barr virus (EBV). We herein report 2 cases of EBV-associated PTLD after allogeneic HSCT localized in the adrenal gland. Both patients developed adrenal tumor within 3 months after HSCT and were successfully treated with rituximab or tapering immunosuppressive agents. Both remained alive without recurrence. A literature review revealed 12 reported cases of PTLD involving the adrenal gland, but the adrenal gland was involved as one of the lesions of advanced-stage PTLD after SOT. To the best of our knowledge, this is the first report to show cases of isolated EBV-associated adrenal PTLD after HSCT. PTLD should be recognized as one of the causes of isolated adrenal tumor after HSCT.
Assuntos
Doenças das Glândulas Suprarrenais/etiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Transtornos Linfoproliferativos/etiologia , Doenças das Glândulas Suprarrenais/tratamento farmacológico , Doenças das Glândulas Suprarrenais/patologia , Adulto , Antineoplásicos/uso terapêutico , Relação Dose-Resposta a Droga , Feminino , Humanos , Imunossupressores/administração & dosagem , Imunossupressores/uso terapêutico , Transtornos Linfoproliferativos/tratamento farmacológico , Transtornos Linfoproliferativos/patologia , Masculino , Rituximab/uso terapêutico , Adulto JovemRESUMO
Adenine nucleotide translocases (ANTs) transport ADP and ATP through mitochondrial inner membrane, thus playing an essential role for energy metabolism of eukaryotic cells. Mice have three ANT paralogs, Ant1 (Slc25a4), Ant2 (Slc25a5) and Ant4 (Slc25a31), which are expressed in a tissue-dependent manner. While knockout mice have been characterized with Ant1 and Ant4 genes, which resulted in exercise intolerance and male infertility, respectively, the role of the ubiquitously expressed Ant2 gene in animal development has not been fully demonstrated. Here, we generated Ant2 hypomorphic mice by targeted disruption of the gene, in which Ant2 expression is largely depleted. The mice showed apparently normal embryonic development except pale phenotype along with a reduced birth rate. However, postnatal growth was severely retarded with macrocytic anemia, B lymphocytopenia, lactic acidosis and bloated stomach, and died within 4 weeks. Ant2 depletion caused anemia in a cell-autonomous manner by maturation arrest of erythroid precursors with increased reactive oxygen species and premature deaths. B-lymphocyte development was similarly affected by Ant2 depletion, and splenocytes showed a reduction in maximal respiration capacity and cellular ATP levels as well as an increase in cell death accompanying mitochondrial permeability transition pore opening. In contrast, myeloid, megakaryocyte and T-lymphocyte lineages remained apparently intact. Erythroid and B-cell development may be particularly vulnerable to Ant2 depletion-mediated mitochondrial dysfunction and oxidative stress.
Assuntos
Translocador 2 do Nucleotídeo Adenina/deficiência , Linfócitos B/citologia , Eritrócitos/citologia , Eritropoese/fisiologia , Linfopoese/fisiologia , Translocases Mitocondriais de ADP e ATP/metabolismo , Translocador 2 do Nucleotídeo Adenina/genética , Translocador 2 do Nucleotídeo Adenina/metabolismo , Trifosfato de Adenosina/metabolismo , Anemia/genética , Anemia/metabolismo , Animais , Linfócitos B/metabolismo , Eritrócitos/metabolismo , Eritropoese/genética , Feminino , Técnicas de Inativação de Genes , Transtornos do Crescimento/genética , Transtornos do Crescimento/metabolismo , Humanos , Linfopoese/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/genética , Mitocôndrias/metabolismoRESUMO
Cortical microtubules are involved in plant resistance to hypergravity, but their roles in resistance to 1 g gravity are still uncertain. To clarify this point, we cultivated an Arabidopsis α-tubulin 6 mutant (tua6) in the Cell Biology Experiment Facility on the Kibo Module of the International Space Station, and analyzed growth and cell wall mechanical properties of inflorescences. Growth of inflorescence stems was stimulated under microgravity conditions, as compared with ground and on-orbit 1 g conditions. The stems were 10-45% longer and their growth rate 15-55% higher under microgravity conditions than those under both 1 g conditions. The degree of growth stimulation tended to be higher in the tua6 mutant than the wild-type Columbia. Under microgravity conditions, the cell wall extensibility in elongating regions of inflorescences was significantly higher than the controls, suggesting that growth stimulation was caused by cell wall modifications. No clear differences were detected in any growth or cell wall property between ground and on-orbit 1 g controls. These results support the hypothesis that cortical microtubules generally play an important role in plant resistance to the gravitational force.
Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Meio Ambiente Extraterreno , Inflorescência/crescimento & desenvolvimento , Mutação/genética , Tubulina (Proteína)/genética , Ausência de Peso , Arabidopsis/citologia , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fenômenos Biomecânicos , Parede Celular/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação , Inflorescência/metabolismo , Fatores de Tempo , Tubulina (Proteína)/metabolismoRESUMO
The chronic toxicity of enzymatically decomposed rutin, which consists mainly of isoquercitrin, was evaluated in male and female Wistar rats with dietary administration at concentrations of 0%, 0.04%, 0.2%, 1% and 5% for 52 weeks. No toxicological findings were found in the mortality, body weights, food consumption, hematology, clinical biochemistry or organ weights in either sex. Obvious clinical signs were chromaturia that could be attributed to the color of test substance in the 5% groups of both sexes. Coloration of the urine collected over 24h in the 1% and 5% groups of both sexes was noted. Increased daily urinary calcium excretion was observed in the 5% groups of both sexes and an increase in urinary calcium concentration was observed in the male 5% group. On histopathological examination, incidences of mineralization, inflammatory cell debris, inflammatory cell infiltration and/or transitional cell hyperplasia in the renal pelvis were increased in the 5% male group, whereas treated females showed no apparent difference in these incidences. Based on the above findings, the no observed adverse effect level (NOAEL) was estimated to be 1% in both sexes (542.4 mg/kg body weight/day for males and 674.0mg/kg body--weight/day for females).
Assuntos
Rutina/toxicidade , Animais , Peso Corporal/efeitos dos fármacos , Cálcio/urina , Dieta , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Aditivos Alimentares , Nefropatias/induzido quimicamente , Nefropatias/patologia , Nefropatias/urina , Masculino , Nível de Efeito Adverso não Observado , Quercetina/análogos & derivados , Quercetina/metabolismo , Quercetina/toxicidade , Ratos , Ratos Wistar , Rutina/metabolismo , Organismos Livres de Patógenos Específicos , Testes de Toxicidade CrônicaRESUMO
It is very important to investigate the confinement of alpha particles, which will be produced by nuclear reactions in ITER and fusion reactors. The pellet charge exchange (PCX) measurement is one of the most powerful methods because it can directly provide the profile of the alpha particle energy spectra in a plasma. In the large helical device, PCX using tracer encapsulated solid pellet (TESPEL) has been tried in many hydrogen and helium plasmas, including helium accelerated by using the cyclotron resonance heating. In the PCX, we use the compact neutral particle analyzer without simultaneous mass separation ability. The helium particle measurement can be achieved by the application of voltage in the condenser plate. The scattering of hydrogen particle is carefully considered during the estimation of the helium amount. The radial helium profiles can also be obtained by comparing four TESPEL injection shots with/without higher harmonic fast wave heating and at applied plate voltages for He or H, respectively.
RESUMO
A wave detector, a newly designed magnetic probe, is installed in the large helical device (LHD). This wave detector is a 100-turn loop coil with electrostatic shield. Comparing a one-loop coil to this detector, this detector has roughly constant power coupling in the lower frequency range of 40 MHz, and it can easily detect magnetic wave in the frequency of a few megahertz. During high-harmonic fast wave heating, lower frequency waves (<10 MHz) were observed in the LHD for the first time, and for the power density threshold of lower frequency wave excitation (7.5 MHz) the power density of excited pumped wave (38.47 MHz) was approximately -46 dBmHz. These lower frequencies are kept constant for electron density and high energy particle distribution, and these lower frequency waves seem to be ion cyclotron waves caused by nonlinear wave-particle interaction, for example, parametric decay instability.
RESUMO
An O-mode reflectometer at a frequency of 25.85 GHz was applied to plasmas heated by the high harmonic fast wave (21 MHz) in the TST-2 spherical tokamak. An oscillation in the phase of the reflected microwave in the rf range was observed directly for the first time. In TST-2, the rf (250 kW) induced density oscillation depends mainly on the poloidal rf electric field, which is estimated to be about 0.2 kV/m rms by the reflectometer measurement. Sideband peaks separated in frequency by ion cyclotron harmonics from 21 MHz, and peaks at ion cyclotron harmonics which are suggested to be quasimodes generated by parametric decay, were detected.
Assuntos
Elétrons , Gases/química , Gases/efeitos da radiação , Oscilometria/instrumentação , Ondas de Rádio , Radiometria/instrumentação , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Oscilometria/métodos , Doses de Radiação , Radiometria/métodos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeAssuntos
Cateterismo Cardíaco/métodos , Seio Coronário/fisiopatologia , Infarto do Miocárdio/fisiopatologia , Infarto do Miocárdio/terapia , Reperfusão Miocárdica/métodos , Regeneração/fisiologia , Terapia Trombolítica/métodos , Adulto , Idoso , Terapia Combinada , Reestenose Coronária/fisiopatologia , Reestenose Coronária/terapia , Vasos Coronários/fisiopatologia , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Vasodilatação/fisiologiaRESUMO
The first successful high power heating of a high dielectric constant spherical tokamak plasma by an electron Bernstein wave (EBW) is reported. An EBW was excited by mode conversion (MC) of an mode cyclotron wave injected from the low magnetic field side of the TST-2 spherical tokamak. Evidence of electron heating was observed as increases in the stored energy and soft x-ray emission. The increased emission was concentrated in the plasma core region. A heating efficiency of over 50% was achieved, when the density gradient in the MC region was sufficiently steep.
RESUMO
Hypoxia represents an endogenous pathophysiological signal underlying cell growth, adaptation and death in a variety of diseases, including ischemic heart diseases, stroke and solid tumors. A vigilant vector system depends on a gene switch which can sense the hypoxia signal occurring in ischemic events and turn on/off protective gene expressions when necessary. This system uses the oxygen-dependent degradation domain derived from hypoxia-inducible factor 1alpha as the hypoxia sensor and a double-vector system as signal amplifier. For treating ischemic heart diseases, a cardiac-specific MLC-2v promoter is used to deliver transgenes specifically to the heart. When tested in cardiomyocyte cultures, it produced a rapid and robust gene induction upon exposure to low oxygen. In a mouse model for myocardial infarction, the vigilant vectors turned on therapeutic genes such as heme oxygenase-1 in response to ischemia, significantly reduced apoptosis in the infarct area and improved cardiac functions. The hypoxia-regulated gene transfer afforded by the vigilant vectors may provide a powerful tool for delivering therapeutic proteins specifically to ischemic tissues with optimal physiological control.
Assuntos
Regulação da Expressão Gênica , Terapia Genética/métodos , Vetores Genéticos/administração & dosagem , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Infarto do Miocárdio/terapia , Miócitos Cardíacos/metabolismo , Animais , Apoptose , Células Cultivadas , Genes de Troca , Engenharia Genética , Vetores Genéticos/genética , Heme Oxigenase-1/genética , Humanos , Hipóxia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Modelos Animais , Estrutura Terciária de Proteína , Ratos , Ratos Sprague-Dawley , Ativação TranscricionalRESUMO
We investigated the biochemical function of the birch pollen allergen Bet v 6 and its role in the IgE-cross-reactivity between birch pollen and plant foods, and characterized Pyr c 5, a Bet v 6-related food allergen, from pear; the proteins were expressed as His-Tag fusion proteins in Eschershia coli and purified by Ni-chelate affinity chromatography under native conditions. Nonfusion proteins were obtained by factor Xa protease treatment. The highest degree of amino-acid sequence identity of Pyr c 5 and Bet v 6 was found with a plant protein related to a defense mechanism, which we have named phenylcoumaran benzylic ether reductase (PCBER) based on its ability to catalyze the NADPH-dependent reduction of 8-5' linked lignans such as dehydrodiconiferyl alcohol to give isodihydrodehydrodiconiferyl alcohol. Enzymatic assays with recombinant Pyr c 5 and Bet v 6 showed PCBER catalytic activity for both recombinant allergens. Both Pyr c 5 and Bet v 6 allergens had similar IgE binding characteristics in immunoblotting and enzyme allergosorbent tests (EAST), and bound IgE from 10 sera of birch-pollen-allergic patients including six pear-allergic subjects. EAST inhibition experiments with Pyr c 5 as the solid phase antigen suggested that homologous allergens may be present in many vegetable foods such as apple, peach, orange, lychee fruit, strawberry, persimmon, zucchini (courgette), and carrot. In extracts of pear, apple, orange, and persimmon, the presence of proteins of approximately 30-35 kDa containing Bet v 6 cross-reactive epitopes was demonstrated with two Bet v 6-specific monoclonal antibodies. Recombinant Pyr c 5 triggered a strong, dose-dependent mediator release from basophils of a pear-allergic subject, suggesting that Pyr c 5 has the potential to elicit type I allergic reactions.
Assuntos
Alérgenos/imunologia , Betula/enzimologia , Betula/imunologia , Frutas/imunologia , Oxirredutases atuantes sobre Doadores de Grupo CH-CH , Oxirredutases/imunologia , Pólen/imunologia , Verduras/imunologia , Alérgenos/química , Alérgenos/genética , Alérgenos/metabolismo , Sequência de Aminoácidos , Betula/genética , Clonagem Molecular , Reações Cruzadas/imunologia , Hipersensibilidade Alimentar/imunologia , Frutas/enzimologia , Liberação de Histamina , Humanos , Hipersensibilidade/imunologia , Soros Imunes/imunologia , Immunoblotting , Imunoglobulina E/imunologia , Dados de Sequência Molecular , NADP/metabolismo , Oxirredutases/química , Oxirredutases/genética , Oxirredutases/metabolismo , Pólen/enzimologia , Homologia de Sequência de Aminoácidos , Verduras/enzimologiaRESUMO
A number of different phenotypes emerge from the mesoderm-derived cardiomyogenic cells of the embryonic tubular heart, including those comprising the cardiac conduction system. The transcriptional regulation of this phenotypic divergence within the cardiomyogenic lineage remains poorly characterized. A relationship between expression of the transcription factor Nkx-2.5 and patterning to form cardiogenic mesoderm subsequent to gastrulation is well established. Nkx-2.5 mRNA continues to be expressed in myocardium beyond the looped, tubular heart stage. To investigate the role of Nkx-2.5 in later development, we have determined the expression pattern of Nkx-2.5 mRNA by in situ hybridization in embryonic chick, fetal mouse, and human hearts, and of Nkx-2.5 protein by immunolocalization in the embryonic chick heart. As development progresses, significant nonuniformities emerge in Nkx-2.5 expression levels. Relative to surrounding force-generating ("working") myocardium, elevated Nkx-2.5 mRNA signal becomes apparent in the specialized cells of the conduction system. Similar differences are found in developing chick, human, and mouse fetal hearts, and nuclear-localized Nkx-2.5 protein is prominently expressed in differentiating chick conduction cells relative to adjacent working myocytes. This tissue-restricted expression of Nkx-2.5 is transient and correlates with the timing of spatio-temporal recruitment of cells to the central and the peripheral conduction system. Our data represent the first report of a transcription factor showing a stage-dependent restriction to different parts of the developing conduction system, and suggest some commonality in this development between birds and mammals. This dynamic pattern of expression is consistent with the hypothesis that Nkx-2.5, and its level of expression, have a role in regulation and/or maintenance of specialized fate selection by embryonic myocardial cells.
Assuntos
Fascículo Atrioventricular/embriologia , Coração/embriologia , Proteínas de Homeodomínio/biossíntese , Miocárdio/citologia , Ramos Subendocárdicos/embriologia , Fatores de Transcrição , Proteínas de Xenopus , Animais , Fascículo Atrioventricular/metabolismo , Embrião de Galinha , Desenvolvimento Embrionário e Fetal , Idade Gestacional , Proteína Homeobox Nkx-2.5 , Proteínas de Homeodomínio/genética , Humanos , Hibridização In Situ , Camundongos , Miocárdio/metabolismo , Ramos Subendocárdicos/metabolismo , RNA Mensageiro/metabolismo , Especificidade da EspécieRESUMO
A DNA nonbinding mutant of the NK2 class homeoprotein Nkx2.5 dominantly inhibits cardiogenesis in Xenopus embryos, causing a small heart to develop or blocking heart formation entirely. Recently, ten heterozygous CSX/NKX2.5 homeoprotein mutations were identified in patients with congenital atrioventricular (AV) conduction defects. All four missense mutations identified in the human homeodomain led to markedly reduced DNA binding. To examine the effect of a DNA binding-impaired mutant of mouse Csx/Nkx2.5 in the embryonic heart, we generated transgenic mice expressing one such allele, I183P, under the beta-myosin heavy chain promoter. Unexpectedly, transgenic mice were born apparently normal, but the accumulation of Csx/Nkx2.5(I183P) mutant protein in the embryo, neonate, and adult myocardium resulted in progressive and profound cardiac conduction defects and heart failure. P-R prolongation observed at 2 weeks of age rapidly progressed into complete AV block as early as 4 weeks of age. Expression of connexins 40 and 43 was dramatically decreased in the transgenic heart, which may contribute to the conduction defects in the transgenic mice. This transgenic mouse model may be useful in the study of the pathogenesis of cardiac dysfunction associated with CSX/NKX2.5 mutations in humans.