Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 431
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Phys Rev Lett ; 132(13): 131001, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38613296

RESUMO

We searched for antideuterons (d[over ¯]'s) in the 4.7×10^{9} cosmic-ray events observed during the BESS-Polar II flight at solar minimum in 2007-2008 but found no candidates. The resulting 95% C.L. upper limit on the d[over ¯] flux is 6.7×10^{-5} (m^{2} s sr GeV/n)^{-1} in an energy range from 0.163 to 1.100 GeV/n. The result has improved by more than a factor of 14 from the upper limit of BESS97, which had a potential comparable to that of BESS-Polar II in the search for cosmic-origin d[over ¯]'s and was conducted during the former solar minimum. The upper limit of d[over ¯] flux from BESS-Polar II is the first result achieving the sensitivity to constrain the latest theoretical predictions.

2.
Phys Rev Lett ; 129(10): 101102, 2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-36112450

RESUMO

A precise measurement of the cosmic-ray proton spectrum with the Calorimetric Electron Telescope (CALET) is presented in the energy interval from 50 GeV to 60 TeV, and the observation of a softening of the spectrum above 10 TeV is reported. The analysis is based on the data collected during ∼6.2 years of smooth operations aboard the International Space Station and covers a broader energy range with respect to the previous proton flux measurement by CALET, with an increase of the available statistics by a factor of ∼2.2. Above a few hundred GeV we confirm our previous observation of a progressive spectral hardening with a higher significance (more than 20 sigma). In the multi-TeV region we observe a second spectral feature with a softening around 10 TeV and a spectral index change from -2.6 to -2.9 consistently, within the errors, with the shape of the spectrum reported by DAMPE. We apply a simultaneous fit of the proton differential spectrum which well reproduces the gradual change of the spectral index encompassing the lower energy power-law regime and the two spectral features observed at higher energies.

3.
Phys Rev Lett ; 128(13): 131103, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35426700

RESUMO

The relative abundance of cosmic ray nickel nuclei with respect to iron is by far larger than for all other transiron elements; therefore it provides a favorable opportunity for a low background measurement of its spectrum. Since nickel, as well as iron, is one of the most stable nuclei, the nickel energy spectrum and its relative abundance with respect to iron provide important information to estimate the abundances at the cosmic ray source and to model the Galactic propagation of heavy nuclei. However, only a few direct measurements of cosmic-ray nickel at energy larger than ∼3 GeV/n are available at present in the literature, and they are affected by strong limitations in both energy reach and statistics. In this Letter, we present a measurement of the differential energy spectrum of nickel in the energy range from 8.8 to 240 GeV/n, carried out with unprecedented precision by the Calorimetric Electron Telescope (CALET) in operation on the International Space Station since 2015. The CALET instrument can identify individual nuclear species via a measurement of their electric charge with a dynamic range extending far beyond iron (up to atomic number Z=40). The particle's energy is measured by a homogeneous calorimeter (1.2 proton interaction lengths, 27 radiation lengths) preceded by a thin imaging section (3 radiation lengths) providing tracking and energy sampling. This Letter follows our previous measurement of the iron spectrum [1O. Adriani et al. (CALET Collaboration), Phys. Rev. Lett. 126, 241101 (2021).PRLTAO0031-900710.1103/PhysRevLett.126.241101], and it extends our investigation on the energy dependence of the spectral index of heavy elements. It reports the analysis of nickel data collected from November 2015 to May 2021 and a detailed assessment of the systematic uncertainties. In the region from 20 to 240 GeV/n our present data are compatible within the errors with a single power law with spectral index -2.51±0.07.

4.
Phys Rev Lett ; 126(24): 241101, 2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34213922

RESUMO

The Calorimetric Electron Telescope (CALET), in operation on the International Space Station since 2015, collected a large sample of cosmic-ray iron over a wide energy interval. In this Letter a measurement of the iron spectrum is presented in the range of kinetic energy per nucleon from 10 GeV/n to 2.0 TeV/n allowing the inclusion of iron in the list of elements studied with unprecedented precision by space-borne instruments. The measurement is based on observations carried out from January 2016 to May 2020. The CALET instrument can identify individual nuclear species via a measurement of their electric charge with a dynamic range extending far beyond iron (up to atomic number Z=40). The energy is measured by a homogeneous calorimeter with a total equivalent thickness of 1.2 proton interaction lengths preceded by a thin (3 radiation lengths) imaging section providing tracking and energy sampling. The analysis of the data and the detailed assessment of systematic uncertainties are described and results are compared with the findings of previous experiments. The observed differential spectrum is consistent within the errors with previous experiments. In the region from 50 GeV/n to 2 TeV/n our present data are compatible with a single power law with spectral index -2.60±0.03.

5.
Br J Cancer ; 113(3): 492-9, 2015 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-26086877

RESUMO

BACKGROUND: SIRT4, which is localised in the mitochondria, is one of the least characterised members of the sirtuin family of nicotinamide adenine dinucleotide-dependent enzymes that play key roles in multiple cellular processes such as metabolism, stress response and longevity. There are only a few studies that have characterised its function and assessed its clinical significance in human cancers. METHODS: We established colorectal cancer cell lines (SW480, HCT116, and HT29) overexpressing SIRT4 and investigated their effects on proliferation, migration and invasion, as well as E-cadherin expression, that negatively regulates tumour invasion and metastases. The associations between SIRT4 expression in colorectal cancer specimens and clinicopathological features including prognosis were assessed by immunohistochemistry. RESULTS: SIRT4 upregulated E-cadherin expression and suppressed proliferation, migration and invasion through inhibition of glutamine metabolism in colorectal cancer cells. Moreover, SIRT4 expression in colorectal cancer decreased with the progression of invasion and metastasis, and a low expression level of SIRT4 was correlated with a worse prognosis. CONCLUSIONS: SIRT4 has a tumour-suppressive function and may serve as a novel therapeutic target in colorectal cancer.


Assuntos
Neoplasias Colorretais/genética , Genes Supressores de Tumor , Proteínas Mitocondriais/fisiologia , Sirtuínas/fisiologia , Movimento Celular/genética , Proliferação de Células/genética , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/patologia , Progressão da Doença , Glutamina/metabolismo , Células HCT116 , Células HT29 , Humanos , Invasividade Neoplásica , Prognóstico , Células Tumorais Cultivadas
6.
J Appl Microbiol ; 116(5): 1218-28, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24450783

RESUMO

AIMS: The aims of this study were to evaluate the effectiveness of nisin A to control the growth of spore-forming bacteria, Bacillus and Paenibacillus, in chilled high-fat, milk pudding and to reduce heat treatment to improve aroma and flavour. METHODS AND RESULTS: Nisin A was added to milk pudding containing 5·0 and 7·5% fat to final concentrations of 40, 80, 120 and 240 IU ml(-1). Spores from Bacillus thuringiensis, Bacillus cereus and Paenibacillus jamilae were inoculated into samples at 10 spores ml(-1) prior to pasteurization at 130°C for 2 s. Milk pudding without inoculation was pasteurized using less heat condition (100, 110 and 120°C for 2 s) to measure the effect of adjusting the ingredients to prevent naturally occurring bacteria. The viable cells during storage at 15, 20 and 30°C showed nisin A inhibited spiked bacteria to varying degrees depending on species, sensitivities to nisin A concentration and fat content, and inhibited natural populations at 80 IU g(-1) nisin A in 5·0% fat and at 120 IU g(-1) in 7·5% fat milk pudding. An aroma compound analysis and organoleptic assessment showed processing at 110 and 120°C decreased the temperature-dependent unpleasant odours, for example, reduced dimethyl sulfide and dimethyl disulfide by 1·2-1·5 times and increased rankings in taste tests compared with 130°C treated pudding. CONCLUSIONS: Nisin A was found to be effective as a natural preservative to control spoilage bacteria in high-fat milk pudding and extend its shelf life, when using reduced heat treatments to improve the flavour and aroma without compromising food safety. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report showing nisin A is effective in reducing spoilage bacteria in high-fat, chilled dessert, milk pudding. Therefore, nisin A can be used to improve milk puddings to satisfy both industry and consumer demand for food quality and safety.


Assuntos
Antibacterianos/farmacologia , Laticínios/microbiologia , Conservantes de Alimentos/farmacologia , Nisina/farmacologia , Bacillus cereus/efeitos dos fármacos , Bacillus thuringiensis/efeitos dos fármacos , Armazenamento de Alimentos , Temperatura Alta , Paenibacillus/efeitos dos fármacos , Esporos Bacterianos/efeitos dos fármacos
7.
Eur Radiol ; 23(10): 2854-60, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23903994

RESUMO

OBJECTIVES: To propose a new classification for ecchordosis physaliphora (EP) using fast imaging employing steady-state acquisition (FIESTA). METHODS: We evaluated 974 consecutive patients and selected for further study 78 (8.0 %) who manifested an excrescence on the dorsal surface of the clivus (DSC) and/or clivus lesions. Lesions were defined as "classical EP" when they appeared as a hyperintense excrescence (cyst-like component) on DSC. Other lesions were defined as "possible EP". RESULTS: Of the 78 patients, 17 (22 %) were diagnosed with classical EP, the other 61 with possible EP. The 61 patients with possible EP were further classified into "incomplete EP = EP bud" (n = 55, 90.2 %), characterised by a T2 hypointense protrusion of the clivus, and into "EP variant" (n = 6, 9.8 %), characterised by hyperintense lesions within only clivus. FIESTA findings of incomplete EP were similar to those of classical EP except for lack of the hyperintense excrescence on DSC. Most lesions were located at the level of the Dorello canal at the midline of the craniospinal axis. CONCLUSION: Our results suggest that the magnetic resonance imaging appearance of EP is diverse. Based on our FIESTA results we propose a new classification for EP, i.e. classical EP, incomplete EP (EP bud) and EP variant. KEY POINTS: • Ecchordosis physaliphora (EP) is a rare benign cystic congenital lesion arising from notochord. • The classical type of EP is frequently associated with a T2 hypointense protrusion. • T2 hypointense protrusions without clivus cysts may represent an incomplete type of EP. • Third type of EP variant only harbours lesions within the clivus.


Assuntos
Neoplasias Encefálicas/epidemiologia , Neoplasias Encefálicas/patologia , Cordoma/epidemiologia , Cordoma/patologia , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Fossa Craniana Posterior/patologia , Diagnóstico Diferencial , Feminino , Humanos , Japão/epidemiologia , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Prevalência , Reprodutibilidade dos Testes , Fatores de Risco , Sensibilidade e Especificidade , Adulto Jovem
8.
J Wound Care ; 22(2): 90-2, 94-7, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23665664

RESUMO

OBJECTIVE: To investigate the hypothesis that stereophotogrammetric wound size monitoring shows suitable inter-observer reliability and user acceptance for clinical practice use. METHOD: Veterans admitted for conservative management of severe pressure ulcers were eligible for inclusion in the study. Three-dimensional (3D) digital wound images were independently captured by two expert and two non-expert nurse-observers using a commercially available stereophotogrammetry system,weekly for 6 weeks.A double-blinded analyst generated 3D wound reconstructions, using software to determine geometry. Clinical opinion of wound progression was provided by an expert physician. RESULTS: Thirteen wounds were assessed with more than 80% of all images being readable. Interclass correlation of 0.9867 (p < 0.000 I) was observed. Compared with clinical opinion, 3D wound measurement was sensitive between improving and static wounds for wound perimeter, volume, depth and length. CONCLUSION: These preliminary findings suggest that 3D wound measurement minimises differences in wound measurement between expert and non-expert observers, suggesting it could be implemented with high reliability in health-care settings where several observers are involved in wound care management.


Assuntos
Fotogrametria/enfermagem , Úlcera por Pressão/patologia , Adulto , Atitude do Pessoal de Saúde , Método Duplo-Cego , Humanos , Imageamento Tridimensional , Variações Dependentes do Observador , Fotogrametria/métodos , Úlcera por Pressão/enfermagem , Estudos Prospectivos , Reprodutibilidade dos Testes , Veteranos
9.
Phys Rev Lett ; 108(5): 051102, 2012 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-22400920

RESUMO

The energy spectrum of cosmic-ray antiprotons (p's) from 0.17 to 3.5 GeV has been measured using 7886 p's detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This shows good consistency with secondary p calculations. Cosmologically primary p's have been investigated by comparing measured and calculated p spectra. BESS-Polar II data show no evidence of primary p's from the evaporation of primordial black holes.

10.
Phys Rev Lett ; 108(13): 131301, 2012 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-22540691

RESUMO

In two long-duration balloon flights over Antarctica, the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) collaboration has searched for antihelium in the cosmic radiation with the highest sensitivity reported. BESS-Polar I flew in 2004, observing for 8.5 days. BESS-Polar II flew in 2007-2008, observing for 24.5 days. No antihelium candidate was found in BESS-Polar I data among 8.4×10(6) |Z|=2 nuclei from 1.0 to 20 GV or in BESS-Polar II data among 4.0×10(7) |Z|=2 nuclei from 1.0 to 14 GV. Assuming antihelium to have the same spectral shape as helium, a 95% confidence upper limit to the possible abundance of antihelium relative to helium of 6.9×10(-8)} was determined combining all BESS data, including the two BESS-Polar flights. With no assumed antihelium spectrum and a weighted average of the lowest antihelium efficiencies for each flight, an upper limit of 1.0×10(-7) from 1.6 to 14 GV was determined for the combined BESS-Polar data. Under both antihelium spectral assumptions, these are the lowest limits obtained to date.

11.
Lett Appl Microbiol ; 50(4): 406-11, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20156306

RESUMO

AIM: The study aimed for the complete purification and recharacterization of the highly hydrophobic circular bacteriocins, gassericin A and reutericin 6. METHODS AND RESULTS: Gassericin A and reutericin 6 were purified to homogeneity using previously described method and reverse-phase HPLC with an octyl column and eluents of aqueous acetonitrile and 2-propanol. Mass analysis, N-terminal sequencing and bacteriocin assay of the HPLC-purified bacteriocins showed the two bacteriocins had identical seamless circular structures with the same m/z value (5651) of [M + H](+) and both had the same specific activity. D/L-amino acid composition analysis using two distinct methods with the chiral fluorescent derivatization reagents (+)-1-(9-fluorenyl)ethyl chloroformate and O-phthalaldehyde/N-acetyl-L-cystein revealed neither gassericin A nor reutericin 6 contained D-alanine residues contrary to our previous results. CONCLUSION: Purified gassericin A and reutericin 6 are chemically identical circular molecules containing no D-alanine residues. SIGNIFICANCE AND IMPACT OF THE STUDY: The HPLC conditions developed in this study will facilitate advanced purification and correct characterization of other highly hydrophobic bacteriocins.


Assuntos
Bacteriocinas/química , Bacteriocinas/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Lactobacillus/química , Espectrometria de Massas
12.
Science ; 258(5082): 618-25, 1992 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-17748896

RESUMO

The Japanese Yohkoh satellite is now in orbit observing the sun with a set of x-ray imagers and x-ray and gamma-ray spectrometers. The data from this successful mission provide new information on solar flares and the sun's corona. This paper discusses the Yohkoh observations and presents a sample of the first scientific results from the mission.

13.
Science ; 257(5072): 954-8, 1992 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-17789640

RESUMO

(40)Ar/(39)Ar dating of drill core samples of a glassy melt rock recovered from beneath a massive impact breccia contained within the 180-kilometer subsurface Chicxulub crater in Yucatán, Mexico, has yielded well-behaved incremental heating spectra with a mean plateau age of 64.98 +/- 0.05 million years ago (Ma). The glassy melt rock of andesitic composition was obtained from core 9 (1390 to 1393 meters) in the Chicxulub 1 well. The age of the melt rock is virtually indistinguishable from (40)Ar/(39)Ar ages obtained on tektite glass from Beloc, Haiti, and Arroyo el Mimbral, northeastern Mexico, of 65.01 +/- 0.08 Ma (mean plateau age for Beloc) and 65.07 +/- 0.10 Ma (mean total fusion age for both sites). The (40)Ar/(39)Ar ages, in conjunction with geochemical and petrological similarities, strengthen the recent suggestion that the Chicxulub structure is the source for the Haitian and Mexican tektites and is a viable candidate for the Cretaceous-Tertiary boundary impact site.

14.
J Dairy Sci ; 92(6): 2365-72, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19447968

RESUMO

Lactobacillus gasseri LA39 and LA158 isolated from human-infant feces produce bacteriocins named gassericins A and T, respectively. Both gassericins have high heat stability (121 degrees C, 10 min), good pH tolerance (pH 2-11), and strong bactericidality against many gram-positive bacteria, especially lactic acid bacteria, and thus are expected to be effective food preservatives. A microwell plate assay against 12 strains of custard cream spoilage bacteria showed that the gassericins had broader antibacterial spectra than nisin A. Although the gassericins allowed gram-negative isolates to grow, they successfully inhibited the growth of all tested bacterial strains in microwells with the addition of glycine. Glycine was bacteriostatic against many strains except lactic acid bacteria. For practical use, gassericin A was efficiently produced by cultivation in a food-grade medium improved using cheese whey, nourishing proteose peptone, and surfactant yolk lecithin. The practical preservative effect of gassericin A and glycine was verified from the viability of 4 isolated strains, Bacillus cereus, Lactococcus lactis ssp. lactis, Achromobacter denitrificans, and Pseudomonas fluorescens, in custard creams. Custard cream containing 123 arbitrary units of gassericin A per milliliter entirely growth-inhibited the 2 gram-positive strains. In custard cream containing an insufficient amount of gassericin A (49 arbitrary units/mL), the gram-positive strains gradually grew but were completely inhibited by the addition of 0.5% (wt/wt) glycine. The 2 gram-negative strains did not multiply even in the additive-free custard cream, probably because of the unsuitable growth environment. This is the first report showing the combined effect of bacteriocin and glycine and their application for food preservation, which may be helpful for future use in the food industry.


Assuntos
Antibiose , Bacteriocinas , Laticínios , Conservação de Alimentos , Glicina , Lactobacillus/química , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Bacteriocinas/farmacologia , Laticínios/análise , Laticínios/microbiologia , Laticínios/normas , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Conservação de Alimentos/normas , Glicina/farmacologia , Acetato de Sódio/farmacologia
15.
J Dairy Sci ; 91(8): 2938-46, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18650270

RESUMO

Custard cream is made from highly nutritive raw materials such as milk and sugar and is easily spoiled by the multiplication of specific microbial contaminants or residents. However, this spoilage microbial community has not been studied. We determined the spoilage microbiota in commercial custard creams using culture-dependent and independent methods. Using the culture-dependent analysis with various agar media, 185 bacterial colonies and 43 eukaryal colonies were isolated from 7 commercial custard cream products. All bacterial isolates were morphologically, physiologically, and genetically identified as bacilli, staphylococci, lactic acid bacteria, and psychrotrophic gram-negative rods. Using culture-independent molecular analysis, the PCR-denaturing gradient gel electrophoresis technique, spoilage of the commercial custard creams was found to be caused by bacilli, staphylococci, lactic acid bacteria, psychrotrophic gram-negative rods, Anoxybacillus sp., Caurobacter sp., and Streptococcus sp. bacteria. The detected spoilage bacteria were the same species as previously detected in spoiled milk products and shown in other reports, suggesting that spoilage bacteria in a raw material easily grow in processed foods made from milk. We determined the spoilage microbial communities in commercial custard creams, and these are the first data concerning spoilage microbiota in nonfermented processed foods using a culture-independent analysis. Our study will be useful for the manufacture and safe preservation of dairy products because the first step toward safe food preservation by food manufacturers is to understand the spoilage microbiota in a target food to select optimal preservatives and to reduce the use of food additives.


Assuntos
Bactérias/classificação , Bactérias/isolamento & purificação , Laticínios/microbiologia , Microbiologia de Alimentos , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Fenômenos Fisiológicos Bacterianos , Técnicas de Tipagem Bacteriana , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , Especificidade da Espécie
16.
Br J Pharmacol ; 151(7): 1014-24, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17549043

RESUMO

BACKGROUND AND PURPOSE: The intravesical administration of dimethyl sulphoxide (DMSO) is used to alleviate the symptoms of interstitial cystitis. We investigated the relaxant effect of DMSO and its underlying mechanism in the detrusor muscle. EXPERIMENTAL APPROACH: The effects of DMSO on contraction, on Ca2+ sensitivity of myofilaments, and on myosin light chain (MLC) phosphorylation were investigated in both intact and alpha-toxin-permeabilized strips of rabbit detrusor muscle. KEY RESULTS: In fura-PE3-loaded strips, DMSO (>1%) induced a significant relaxation during sustained contractions induced by 60 mM K+-depolarization or 10 microM carbachol, while having no effect on the [Ca2+](i) level. DMSO decreased the level of MLC phosphorylation during the contractions induced by 60 mM K+ and 10 microM carbachol. DMSO also inhibited both the contraction and MLC phosphorylation induced by calyculin-A in intact strips. In the alpha-toxin-permeabilized preparations, DMSO relaxed the Ca2+-induced contraction and also inhibited the tension development induced by a stepwise increment of Ca2+ concentrations. Such a relaxant effect of DMSO was enhanced in the presence of phosphate. CONCLUSIONS AND IMPLICATIONS: DMSO relaxes rabbit detrusor muscle by decreasing the Ca2+ sensitivity of myofilaments. Inhibition of the kinase activities involved in myosin phosphorylation may play a major role in DMSO-induced Ca2+ desensitization. Inhibition of the cross-bridge cycling at the step of phosphate release may also contribute to the relaxant effect of DMSO. Such relaxant effects of DMSO could be linked to the therapeutic effect of DMSO in interstitial cystitis.


Assuntos
Cálcio/farmacologia , Dimetil Sulfóxido/farmacologia , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Bexiga Urinária/efeitos dos fármacos , Actinas/metabolismo , Analgésicos não Narcóticos/farmacologia , Androstadienos/farmacologia , Animais , Aorta/efeitos dos fármacos , Aorta/metabolismo , Aorta/fisiologia , Cálcio/metabolismo , Calmodulina/farmacologia , Carbacol/farmacologia , Agonistas Colinérgicos/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Técnicas In Vitro , Masculino , Relaxamento Muscular/efeitos dos fármacos , Músculo Liso/fisiologia , Cadeias Leves de Miosina/metabolismo , Quinase de Cadeia Leve de Miosina/metabolismo , Fosfatos/metabolismo , Fosforilação/efeitos dos fármacos , Cloreto de Potássio/farmacologia , Coelhos , Ratos , Fosfolipases Tipo C/farmacologia , Bexiga Urinária/metabolismo , Bexiga Urinária/fisiologia , Wortmanina
17.
Br J Pharmacol ; 150(4): 434-44, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17220909

RESUMO

BACKGROUND AND PURPOSE: Although vascular smooth muscle cells are known to express the Na+-Ca2+ exchanger (NCX), its functional role has remained unclear, mainly because of its relatively low expression. We thus investigated the involvement of NCX in the mechanism for the forskolin-induced vaso-relaxation, using wild type (WT) and transgenic (TG) mice that specifically over-express NCX1.3 in smooth muscle. EXPERIMENTAL APPROACH: We examined the relaxing effect of forskolin during the pre-contraction induced by 100 nM U46619, a thromboxane A2 analogue in the mouse isolated thoracic aorta. We also measured the intracellular Ca2+ concentration ([Ca2+]i) in fura-PE3-loaded aortic strips. KEY RESULTS: The forskolin-induced decreases in [Ca2+]i and tension were much greater in aortas from TG mice than in those from WT mice. In a low Na+ solution, forskolin-induced decreases in [Ca2+]i and tension were greatly inhibited in both groups of aortas. In WT aortas, the presence of 100 nM SEA0400, an NCX inhibitor, had only a little effect on the forskolin-induced decreases in [Ca2+]i, but inhibited the forskolin-induced relaxation. However, in TG aortas, the presence of SEA0400 greatly inhibited the forskolin-induced decreases in [Ca2+]i and tension. CONCLUSIONS AND IMPLICATIONS: The NCX was involved in the forskolin-induced reduction of [Ca2+]i and tension in the mouse thoracic aorta. Measurement of [Ca2+]i and tension in aortas of the TG mouse is thus considered to be a useful tool for evaluating the role of NCX in vascular tissue.


Assuntos
AMP Cíclico/fisiologia , Músculo Liso Vascular/fisiologia , Trocador de Sódio e Cálcio/fisiologia , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacologia , Compostos de Anilina/farmacologia , Animais , Aorta/citologia , Aorta/efeitos dos fármacos , Aorta Torácica/citologia , Aorta Torácica/efeitos dos fármacos , Cálcio/metabolismo , Colforsina/antagonistas & inibidores , Colforsina/farmacologia , Dinoprosta/farmacologia , Cães , Corantes Fluorescentes , Fluorometria , Fura-2/análogos & derivados , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Contração Muscular/efeitos dos fármacos , Contração Muscular/fisiologia , Relaxamento Muscular/fisiologia , Éteres Fenílicos/farmacologia , Sódio/fisiologia , Trocador de Sódio e Cálcio/genética , Vasoconstritores/farmacologia
18.
Cancer Res ; 49(9): 2405-8, 1989 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-2706628

RESUMO

Modulation of the synthesis of heat shock proteins in HL-60 human promyelocytic leukemia cells during differentiation was studied by metabolic labeling with [35S]methionine and Northern blot analysis. HL-60 cells were found to synthesize constitutively a high level of a Mr 90,000 protein (heat shock cognate protein, hsc90), which was very closely related to Mr 90,000 heat shock protein, hsp90, as far as molecular weight, isoelectric point, peptide maps, immunoreactivity, and encoded mRNA were concerned. Differentiation induction by dimethyl sulfoxide markedly decreased the level of the hsc90 expression, but preserved the ability to preferentially express hsp90 in response to heat stress. These results suggest distinct regulatory mechanisms of the synthesis between hsc90 and hsp90 although they are indistinguishable by conventional protein or mRNA analysis, and indicate that hsc90 has some role in cell growth and differentiation.


Assuntos
Granulócitos/patologia , Proteínas de Choque Térmico/biossíntese , Leucemia Promielocítica Aguda/patologia , Diferenciação Celular , Proteínas de Choque Térmico/genética , Temperatura Alta , Humanos , Leucemia Promielocítica Aguda/metabolismo , Peso Molecular , RNA Mensageiro/análise , Células Tumorais Cultivadas
19.
Cancer Res ; 55(14): 3192-6, 1995 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-7606740

RESUMO

The cell line AR230 was established from the peripheral blood mononuclear cells of a patient with chronic myeloid leukemia and t(9;22) translocation bearing a variant type of BCR/ABL rearrangement. AR230 expresses a BCR/ABL fusion protein with a molecular mass of 230 kilodaltons (kDa) due to the insertion of 180 amino acids encoded by 3' exons of BCR (b4 to c3). An immune complex kinase assay showed that the 230-kDa BCR/ABL protein ahd autophosphorylation activity. Immunoprecipitation analysis revealed a stable complex of GRB2 and 230-kDa BCR/ABL proteins, indicating that the Ras activation pathway is involved in the process of transformation. AR230 expressed another short transcript consisting of a BCRc2/ABL junction, which is associated with a stop signal shortly after the junction. To our knowledge, this is the first cell line expressing a 230-kDa fusion product of BCR/ABL. AR230 will be useful for studying the biological function of divergent BCR/ABL proteins.


Assuntos
Proteínas de Fusão bcr-abl/biossíntese , Proteínas de Fusão bcr-abl/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Células Tumorais Cultivadas , Sequência de Aminoácidos , Complexo Antígeno-Anticorpo/metabolismo , Antígenos de Superfície/análise , Sequência de Bases , Southern Blotting , Cromossomos Humanos Par 22 , Cromossomos Humanos Par 9 , Éxons , Feminino , Rearranjo Gênico , Genes abl , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Pessoa de Meia-Idade , Dados de Sequência Molecular , Fosfotransferases/metabolismo , Testes de Precipitina , Translocação Genética
20.
Astrophys J ; 822(2)2016 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32713958

RESUMO

The BESS-Polar Collaboration measured the energy spectra of cosmic-ray protons and helium during two long-duration balloon flights over Antarctica in December 2004 and December 2007, at substantially different levels of solar modulation. Proton and helium spectra probe the origin and propagation history of cosmic rays in the galaxy, and are essential to calculations of the expected spectra of cosmic-ray antiprotons, positrons, and electrons from interactions of primary cosmic-ray nuclei with the interstellar gas, and to calculations of atmospheric muons and neutrinos. We report absolute spectra at the top of the atmosphere for cosmic-ray protons in the kinetic energy range 0.2-160 GeV and helium nuclei 0.15-80 GeV/nucleon. The corresponding magnetic rigidity ranges are 0.6-160 GV for protons and 1.1-160 GV for helium. These spectra are compared to measurements from previous BESS flights and from ATIC-2, PAMELA, and AMS-02. We also report the ratio of the proton and helium fluxes from 1.1 GV to 160 GV and compare to ratios from PAMELA and AMS-02.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA