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1.
Phys Rev Lett ; 127(11): 113601, 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34558916

RESUMO

This theoretical work initiates contact between two frontier disciplines of physics, namely, atomic superfluid rotation and cavity optomechanics. It considers an annular Bose-Einstein condensate, which exhibits dissipationless flow and is a paradigm of rotational quantum physics, inside a cavity excited by optical fields carrying orbital angular momentum. It provides the first platform that can sense ring Bose-Einstein condensate rotation with minimal destruction, in situ and in real time, unlike demonstrated techniques, all of which involve fully destructive measurement. It also shows how light can actively manipulate rotating matter waves by optomechanically entangling persistent currents. Our work opens up a novel and useful direction in the sensing and manipulation of atomic superflow.

2.
Br J Dermatol ; 185(3): 627-635, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33733456

RESUMO

BACKGROUND: Cutaneous immune-related adverse events (cirAEs) are a common side-effect of immune checkpoint inhibitors (ICIs). However, prior work examining these toxicities in detail has considered only the fraction of events evaluated by dermatologists. Associations between dermatology referral, cirAE treatment and survival outcomes remain underexplored across care settings. OBJECTIVES: To comprehensively categorize cirAE patterns among all patients treated with immunotherapy at our institution, and to evaluate: (i) the effect of dermatology referral on cirAE treatment and (ii) the impact of cirAE treatment on survival. METHODS: This was a retrospective cohort analysis of patients with cancer who initiated ICI therapy between 1 January 2016 and 8 March 2019 and developed one or more cirAEs, as screened for using International Classification of Diseases 10th revision codes and confirmed via manual chart review (n = 358). All relevant information documented prior to 31 March 2020 was included. RESULTS: CirAEs evaluated by dermatologists were significantly more likely to be treated than cirAEs that were not referred (odds ratio 6·08, P < 0·001). Patients who received any cirAE treatment had improved progression-free survival [hazard ratio (HR) 0·59, P = 0·001] and overall survival (HR 0·58, P = 0·007) compared with those who did not. CONCLUSIONS: CirAEs evaluated by dermatologists were significantly more likely to be treated than cirAEs that were not referred, and patients who received any treatment for a cirAE had improved survival outcomes.


Assuntos
Imunoterapia , Neoplasias , Humanos , Neoplasias/tratamento farmacológico , Intervalo Livre de Progressão , Encaminhamento e Consulta , Estudos Retrospectivos
3.
Phys Rev Lett ; 121(25): 250401, 2018 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-30608846

RESUMO

We demonstrate synthetic azimuthal gauge potentials for Bose-Einstein condensates from engineering atom-light couplings. The gauge potential is created by adiabatically loading the condensate into the lowest energy Raman-dressed state, achieving a coreless vortex state. The azimuthal gauge potentials act as effective rotations and are tunable by the Raman coupling and detuning. We characterize the spin textures of the dressed states, in agreements with the theory. The lowest energy dressed state is stable with a 4.5-s half-atom-number-fraction lifetime. In addition, we exploit the azimuthal gauge potential to demonstrate the Hess-Fairbank effect, the analogue of Meissner effect in superconductors. The atoms in the absolute ground state has a zero quasiangular momentum and transits into a polar-core vortex when the synthetic magnetic flux is tuned to exceed a critical value. Our demonstration serves as a paradigm to create topological excitations by tailoring atom-light interactions where both types of SO(3) vortices in the |⟨F[over →]⟩|=1 manifold, coreless vortices and polar-core vortices, are created in our experiment. The gauge field in the stationary Hamiltonian opens a path to investigating rotation properties of atomic superfluids under thermal equilibrium.

7.
Nature ; 465(7298): 590-3, 2010 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-20520708

RESUMO

A network is frustrated when competing interactions between nodes prevent each bond from being satisfied. This compromise is central to the behaviour of many complex systems, from social and neural networks to protein folding and magnetism. Frustrated networks have highly degenerate ground states, with excess entropy and disorder even at zero temperature. In the case of quantum networks, frustration can lead to massively entangled ground states, underpinning exotic materials such as quantum spin liquids and spin glasses. Here we realize a quantum simulation of frustrated Ising spins in a system of three trapped atomic ions, whose interactions are precisely controlled using optical forces. We study the ground state of this system as it adiabatically evolves from a transverse polarized state, and observe that frustration induces extra degeneracy. We also measure the entanglement in the system, finding a link between frustration and ground-state entanglement. This experimental system can be scaled to simulate larger numbers of spins, the ground states of which (for frustrated interactions) cannot be simulated on a classical computer.

9.
Br J Cancer ; 104(1): 166-74, 2011 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-21119667

RESUMO

BACKGROUND: The underlying mechanisms involved in the activation of hypoxia-inducible factor-1 (HIF-1) in gastric cancer remain unclear. As nuclear factor-κB (NF-κB) as well as HIF-1 have been implicated in angiogenesis of various cancers, we investigated their relationship in gastric cancer. METHODS: Nuclear expressions of HIF-1α and NF-κB/RelA were assessed in 251 human gastric carcinoma specimens by immunohistochemical tissue array analysis. Stable human gastric cancer cells, infected with a retroviral vector containing super-suppressive mutant form of IκBα (IκBαM), were used for animal studies as well as cell culture experiments. Xenografted tumours were measured and IκBαM effects on angiogenesis and HIF-1α activation were assessed by immunohistochemistry, western blotting, luciferase reporter assay, and semiquantitative reverse transcription-polymerase chain reaction. In addition, NF-κB effects on the HIF-1α degradation and synthesis were examined. RESULTS: Hypoxia-inducible factor-1α activation positively correlated with RelA activation in clinical gastric cancer samples (P<0.001). The IκBαM overexpression suppressed tumour growth, microvessel density, and HIF-1α activation in xenografted tumours. Cell culture experiments showed that hypoxia-induced HIF-1α expression was reduced by NF-κB inhibition under hypoxic conditions at the translational level. CONCLUSION: The hypoxia-dependent activation of the NF-κB/HIF-1α/VEGF pathway contributes, at least in part, to gastric cancer promotion via enhancement of angiogenesis.


Assuntos
Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Hipóxia , NF-kappa B/metabolismo , Neovascularização Patológica , Neoplasias Gástricas/irrigação sanguínea , Neoplasias Gástricas/patologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Apoptose , Western Blotting , Movimento Celular , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Proteínas I-kappa B/genética , Proteínas I-kappa B/metabolismo , Técnicas Imunoenzimáticas , Luciferases/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Inibidor de NF-kappaB alfa , NF-kappa B/antagonistas & inibidores , NF-kappa B/genética , Invasividade Neoplásica , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Neoplasias Gástricas/metabolismo , Células Tumorais Cultivadas , Fator A de Crescimento do Endotélio Vascular/genética , Ensaios Antitumorais Modelo de Xenoenxerto
10.
J Eur Acad Dermatol Venereol ; 24(2): 163-7, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19614858

RESUMO

BACKGROUND: Eruptive pseudo-angiomatosis (EPA) is a rare, relatively newly described cutaneous disorder characterized by the sudden onset of several bright red, angioma-like papules surrounded by blanched halo. Its aetiology is unknown; however, viral infection or mosquito bites have been speculated as possible causes. OBJECTIVE: This study aims to determine the clinical and histopathological features of EPA, and whether it is associated with Epstein-Barr virus (EBV) infection. METHODS: We conducted a retrospective chart review of 25 EPA cases from 2006 to 2008. In order to determine latent EBV infection, EBV-encoded small RNA (EBER) in situ hybridization was performed in 18 subjects. To determine EPA's distinguishing histological characteristics, we compared the cases with 22 control cases of perivascular lymphocytic infiltration for haematoxylin and eosin, CD3, CD4, CD8, CD31 and c-kit staining patterns. RESULTS: The patient sample's female-to-male ratio was 2.1 : 1, and the patients' age ranged from 5 to 79 years (average 46 years). The lesions appeared during the months of July to September in all but 3 patients. Skin biopsies demonstrated capillary ectasia with perivascular mononuclear cellular infiltrates in the upper dermis. Most patients were otherwise healthy, and routine laboratory results were all normal except in one patient who had diabetes. The skin lesions faded without any treatment in 1-2 weeks. Results of EBER in situ hybridization were all negative. The only histological distinguishing feature of EPA was the presence of intravascular neutrophils, which was found to be present in 19 of the 20 EPA cases (95%), in contrast to only 3 of the 22 control subjects (14%) (P < 0.0001). CONCLUSION: The sudden onset of lesions during the summer months among our patients supports the 'paraviral eruption' concept of this probably underdiagnosed condition. The significant presence of intravascular neutrophils may be a diagnostic clue of EPA in South Korea.


Assuntos
Angiomatose/patologia , Herpesvirus Humano 4/isolamento & purificação , Neutrófilos/patologia , Adulto , Idoso , Angiomatose/virologia , Estudos de Casos e Controles , Pré-Escolar , Feminino , Herpesvirus Humano 4/genética , Humanos , Hibridização In Situ , Masculino , Pessoa de Meia-Idade , RNA Viral/genética , RNA Viral/isolamento & purificação , Estudos Retrospectivos
11.
J Int Med Res ; 37(1): 154-62, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19215685

RESUMO

The effects of midazolam used with low concentration inhaled anaesthetics on the bispectral index (BIS) was investigated after fetal expulsion during caesarean section. Forty-five patients undergoing caesarean section received either normal saline (control, n = 15), or an intravenous bolus of 0.03 mg/kg (n = 15) or 0.05 mg/kg (n = 15) midazolam. Changes in BIS and maternal haemodynamics were monitored before induction, on intubation, at uterine incision, on delivery, at 3, 5 and 10 min after fetal expulsion, at subcutaneous tissue closure, at skin closure, on eye opening and at extubation. BIS values in the group that received 0.05 mg/kg midazolam were significantly lower than in the other two groups at 3, 5 and 10 min after fetal expulsion, and at subcutaneous tissue closure and skin closure. Values of BIS < 60 could only be maintained with 0.05 mg/kg midazolam and there was no delay in maternal emergence or recovery.


Assuntos
Anestesia Geral , Cesárea , Éteres Metílicos/farmacologia , Midazolam/farmacologia , Adulto , Período de Recuperação da Anestesia , Feminino , Humanos , Recém-Nascido , Sevoflurano , Resultado do Tratamento
12.
Genes Immun ; 9(8): 668-79, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18769441

RESUMO

We identified a novel soluble protein, mouse (m)IL-20R1a, generated by alternative splicing of the mIL-20R1 gene, which encodes one subunit of the receptor complex for mIL-19, mIL-20 and mIL-24. mIL-20R1a has 77.14% amino-acid identity with the extracellular domain of mIL-20R1. However, no significant interaction between mIL-20R1a and mIL-19 or mIL-20 was detected. Consequently, we aimed to clarify whether mIL-20R1a might function as a novel effector on certain cells. Competitive binding assays demonstrated that mIL-20R1a bound to cell surfaces and resulted in AKT and JNK phosphorylation in primary mesangial cells (MCs) isolated from either the wild-type mice, DBA/W mice, or the SLE-prone mice, NZB/W mice. NZB/W MCs expressed more mIL-20R1a transcript than DBA/W MCs did. Furthermore, mIL-20R1a-treated NZB/W MCs produced higher level of chemokines, renal fibrogenic factors and ROS than mIL-20R1a-treated DBA/W MCs did. These factors are involved in the pathogenesis of lupus nephritis. Endogenous mIL-20R1a was upregulated in the bladder, colon and spleen tissue of NZB/W mice. Elevated mIL-20R1a in the spleen tissue of NZB/W mice was expressed mainly in monocytes and B cells. mIL-20R1a further induced mIL-10 production by the anti-IgM antibody-stimulated B cells in NZB/W mice. Therefore, mIL-20R1a-mediated effects may exacerbate the disease outcome of lupus nephritis.


Assuntos
Citocinas/metabolismo , Nefrite Lúpica/imunologia , Células Mesangiais/imunologia , Receptores de Interleucina/genética , Angiotensina II/farmacologia , Animais , Citocinas/imunologia , Modelos Animais de Doenças , Mesângio Glomerular/efeitos dos fármacos , Mesângio Glomerular/imunologia , Mesângio Glomerular/metabolismo , Lipopolissacarídeos/farmacologia , Nefrite Lúpica/metabolismo , Células Mesangiais/efeitos dos fármacos , Células Mesangiais/metabolismo , Camundongos , Camundongos Endogâmicos DBA , Camundongos Endogâmicos NZB , Fator de Crescimento Derivado de Plaquetas/farmacologia , Espécies Reativas de Oxigênio/imunologia , Espécies Reativas de Oxigênio/metabolismo , Receptores de Interleucina/imunologia , Receptores de Interleucina/isolamento & purificação , Receptores de Interleucina/metabolismo
13.
Genes Immun ; 9(5): 395-404, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18496552

RESUMO

Acute renal failure is an abrupt decrease in renal function. Interleukin (IL)-10 inhibits ischemic and cisplatin-induced acute renal failure. We aimed to determine whether IL-20 affects renal tubular epithelial cells and is associated with acute renal failure. We analyzed the expression of IL-20 and its receptor (R) in the kidneys of rats with HgCl(2)-induced acute renal failure. Reverse transcription-PCR showed upregulated IL-20, and its receptors and immunohistochemical staining showed strongly expressed IL-20 protein in proximal tubular epithelial cells. We analyzed human proximal tubular epithelial (HK-2) cells, which expressed both IL-20 and its receptors. IL-20 specifically induced mitochondria-dependent apoptosis by activating caspase 9 in HK-2 cells. IL-20 also activated c-Jun N-terminal kinase and extracellular signal-regulated kinase 1/2, the downstream signals implicated in the apoptosis of HK-2 cells. Furthermore, IL-20 upregulated the transcripts of transforming growth factor (TGF)-beta1, a critical mediator of renal injury. In hypoxic HK-2 cells, IL-20 and IL-22R1 transcripts increased, and IL-20 upregulated IL-1 beta transcripts. In vivo study further demonstrated that anti-IL-20 antibody reduced the expression of TGF-beta1 and IL-1 beta and the number of damaged tubular cells in the kidneys of rats with acute renal failure. We concluded that IL-20 may be involved in the injury of renal epithelial cells in acute renal failure.


Assuntos
Injúria Renal Aguda/tratamento farmacológico , Anticorpos Monoclonais , Interleucinas/fisiologia , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/imunologia , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/imunologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Sequência de Bases , Western Blotting , Morte Celular , Linhagem Celular , Células Cultivadas , Humanos , Imuno-Histoquímica , Interleucinas/genética , Interleucinas/imunologia , Túbulos Renais Proximais/efeitos dos fármacos , Masculino , Cloreto de Mercúrio/farmacologia , Dados de Sequência Molecular , Ratos , Ratos Sprague-Dawley , Transdução de Sinais
14.
Sci Rep ; 8(1): 9570, 2018 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-29934557

RESUMO

We theoretically investigate the light scattering of super- and subradiant states of an atomic ring prepared by single excitation with a photon which carries an orbital angular momentum (OAM). For excitations with linear polarizations, the helical phase imprinted (HPI) atomic ring presents a discrete C4 rotational symmetry when number of atoms N = 4n with integers n, while for circular polarizations with arbitrary N, the continuous and C N symmetries emerge for the super- and subradiant modes, respectively. The HPI superradiant modes predominantly scatter photons in the forward-backward direction, and the forward scattering can be further enhanced as atomic rings are stacked along the excitation direction. The HPI subradiant modes then preferentially scatter photons in the transversal directions, and when rings are stacked concentrically and on a plane, crossover from sub- to superradiance is observed which leads to splitting and localization of the far-field scattering patterns in the polar angle. The HPI super- and subradiant states are thus detectable through measuring the far-field radiation patterns, which further allow quantum storage and detection of a single photon with an OAM.

15.
J Clin Invest ; 78(6): 1462-71, 1986 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3782467

RESUMO

Differences in aortic impedance between normotensives and hypertensives are not well characterized. We examined impedance in 8 normotensive and 11 hypertensive (mean 96.7 vs. 122.2 mmHg) age-matched, Chinese patients undergoing cardiac catheterization at rest, during nitroprusside, and handgrip exercise before and after beta blockade (propranolol). Hypertensives had higher resistance (2,295 vs. 1713 dyn-s/cm5), characteristic impedance (145.7 vs. 93.9 dyn-s/cm5), total external power (1,579 vs. 1174 mW), peripheral reflections (ratio of backward to forward wave components of 0.54 vs. 0.44), and first zero crossing of impedance phase angle (4.15 vs. 2.97 Hz). These abnormalities were eliminated with vasodilatation. Differences between groups were not further exacerbated when pressure was increased during handgrip exercise. Beta blockade further increased resistance and reflections. Thus, hemodynamic abnormalities of essential hypertension (increased resistance, reflections, and pulse wave velocity, and decreased compliance) are compatible with an increased vasomotor tone that is further unmasked during generalized beta blockade.


Assuntos
Hemodinâmica , Hipertensão/fisiopatologia , Adulto , Fatores Etários , Aorta/fisiopatologia , Artérias/fisiopatologia , Condutividade Elétrica , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Nitroprussiato/farmacologia , Esforço Físico , Propranolol/farmacologia
16.
J Int Med Res ; 35(1): 52-8, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17408055

RESUMO

We investigated the effect of IV nicardipine on haemodynamic and bispectral index responses to the induction of general anaesthesia and intubation. Forty patients were randomly allocated to two groups of 20 to receive normal saline or nicardipine 15 microg/kg IV 30 s after induction. Ninety seconds later, tracheal intubation was performed. Systolic blood pressure, heart rate and bispectral index were measured at baseline, 1 min after induction, pre-intubation, and every minute until 5 min after endotracheal intubation. Rate-pressure product values were calculated. In the nicardipine group, systolic blood pressure decreased compared with the control group, and heart rate increased comparedwith the control group. Bispectral index and rate-pressure product showed no differences between the two groups. In conclusion, the administration of 15 microg/kg nicardipine IV does not affect anaesthetic depth in response to the induction of general anaesthesia and intubation.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Bloqueadores dos Canais de Cálcio/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Intubação Intratraqueal , Nicardipino/farmacologia , Adolescente , Adulto , Humanos , Pessoa de Meia-Idade
17.
Aliment Pharmacol Ther ; 45(8): 1073-1083, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28225186

RESUMO

BACKGROUND: Oltipraz is a synthetic dithiolethione with an antisteatotic effect by inhibiting the activity of liver X receptor alpha (LXR-α). Recent studies demonstrated the disruptive role of oltipraz on LXR-α-dependent lipogenesis in hepatocytes and a high-fat diet mouse model. AIM: To evaluate the efficacy and safety of oltipraz for reducing liver fat in subjects with non-alcoholic fatty liver disease (NAFLD). METHODS: We performed a multicentre, double-blind, placebo-controlled, phase II study. Subjects with a liver fat >20% and hypertransaminasemia were randomised to the three groups: placebo (n = 22), 30 mg of oltipraz (n = 22) or 60 mg of oltipraz (n = 24) twice daily for 24 weeks. Changes in the liver fat from baseline to 24 weeks quantified using magnetic resonance spectroscopy were the primary outcome. RESULTS: Compared with the placebo group (-3.2 ± 11.1%), absolute changes in the liver fat content increased in a dose-dependent manner: -7.7 ± 7.0% and -13.9 ± 10.7% for the low-dose and high-dose groups (P = 0.13 and P < 0.01). Per cent reduction in the liver fat content was also significantly greater in the high-dose group than in the placebo group (-34.6 ± 29.4% vs. -0.6 ± 62.9%, P = 0.046). Body mass indices (-1.0 ± 0.9% vs. -0.5 ± 1.4%, P = 0.04) significantly decreased in the high-dose group compared to the placebo group. However, absolute changes in insulin resistance, liver enzymes, lipids and cytokines were not significantly different among groups. The incidence of adverse events was comparable among groups. CONCLUSIONS: Twenty-four-week oltipraz treatment significantly reduced the liver fat content in patients with NAFLD. Clinicaltrials.gov (NCT01373554).


Assuntos
Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Pirazinas/uso terapêutico , Adulto , Animais , Método Duplo-Cego , Fígado Gorduroso/diagnóstico , Fígado Gorduroso/tratamento farmacológico , Fígado Gorduroso/metabolismo , Feminino , Humanos , Receptores X do Fígado/antagonistas & inibidores , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Hepatopatia Gordurosa não Alcoólica/metabolismo , Pirazinas/farmacocinética , Tionas , Tiofenos , Resultado do Tratamento , Ultrassonografia
18.
Cancer Res ; 59(9): 2023-8, 1999 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-10232579

RESUMO

Using the palindromic PCR-cDNA display method, we have cloned a novel gene overexpressed by human colon carcinoma relative to normal colon. Among normal tissues examined, only testis expresses it at a high level. Sequence analysis revealed its extensive homology with checkpoint genes rad17 of Schizosaccharomyces pombe and RAD24 of Saccharomyces cerevisiae. This novel gene designated as hRad17 is localized to chromosome 5q12,13.1, a region known to be deleted in a variety of human cancers. Promoter region and one pseudogene of hRad17 have been identified. Whereas the increased expression of hRad17 by human colon carcinomas may be related to the known resistance of these cells to DNA-damaging agents during therapy, the deletion of hRad17 in a variety of cancers may predispose them to increased rate of mutation and heightened sensitivity to DNA-damaging agents, including radiation and anticancer drugs.


Assuntos
Carcinoma/metabolismo , Proteínas de Ciclo Celular/biossíntese , Proteínas de Ciclo Celular/genética , Ciclo Celular/genética , Cromossomos Humanos Par 5/genética , Neoplasias Colorretais/metabolismo , Proteínas Fúngicas/genética , Regulação Neoplásica da Expressão Gênica , Genes , Proteínas de Neoplasias/biossíntese , Saccharomyces cerevisiae/genética , Schizosaccharomyces/genética , Animais , Sequência de Bases , Carcinoma/genética , Chlorocebus aethiops/genética , Clonagem Molecular , Neoplasias Colorretais/genética , Dano ao DNA , DNA Complementar/genética , Proteínas de Ligação a DNA , Deleção de Genes , Genes Fúngicos , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Camundongos , Dados de Sequência Molecular , Proteínas de Neoplasias/genética , Proteínas Nucleares , Reação em Cadeia da Polimerase , Regiões Promotoras Genéticas , Pseudogenes/genética , Proteínas de Saccharomyces cerevisiae , Proteínas de Schizosaccharomyces pombe , Testículo/metabolismo
19.
J Neurosci ; 21(24): 9619-28, 2001 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11739572

RESUMO

G-protein-coupled receptors (GPCRs) induce the phosphorylation of mitogen-activated protein (MAP) kinase by actions on any of a number of signal transduction systems. Previous studies have revealed that activation of the G(q)-coupled metabotropic glutamate receptor 5 (mGluR5) induces phosphorylation of the MAP kinase extracellular signal-regulated kinase 2 (ERK2) in cultured rat cortical astrocytes. We performed a series of studies to determine the mechanisms underlying mGluR5-induced phosphorylation of MAP kinase in these cells. Interestingly, our studies suggest that mGluR5-mediated ERK2 phosphorylation is dependent on the activation of G(alphaq) but is not mediated by the activation of phospholipase Cbeta1, activation of protein kinase C, or increases in intracellular calcium. Studies with peptide inhibitors suggest that this response is not dependent on G(betagamma) subunits. However, the activation of ERK2 was dependent on activation of the epidermal growth factor (EGF) receptor and activation of a Src family tyrosine kinase. Furthermore, activation of mGluR5 induced an association of this receptor and the EGF receptor, suggesting the formation of a signaling complex involved in the activation of ERK2. These data suggest that mGluR5 increases ERK2 phosphorylation in astrocytes by a novel mechanism involving the activation of G(alphaq) and both receptor and nonreceptor tyrosine kinases but that is independent of the activation of phospholipase Cbeta1.


Assuntos
Astrócitos/metabolismo , Receptores ErbB/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Ativação Transcricional/fisiologia , Animais , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Células Cultivadas , Inibidores Enzimáticos/farmacologia , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Agonistas de Aminoácidos Excitatórios/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP , Proteínas de Ligação ao GTP/metabolismo , Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Proteína Quinase 3 Ativada por Mitógeno , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Peptídeos/farmacologia , Fosfatidilinositóis/metabolismo , Fosfolipase C beta , Fosforilação/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , Subunidades Proteicas , Proteínas Tirosina Fosfatases/antagonistas & inibidores , Quinazolinas , Ratos , Ratos Sprague-Dawley , Receptor de Glutamato Metabotrópico 5 , Receptores de Glutamato Metabotrópico/agonistas , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Fosfolipases Tipo C/antagonistas & inibidores , Fosfolipases Tipo C/metabolismo , Tirfostinas/farmacologia , Quinases da Família src/metabolismo
20.
Biochim Biophys Acta ; 655(2): 230-42, 1981 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-7284385

RESUMO

Proteins extracted from wheat germ 60 S ribosomal subunits and rat liver 60 S and 40 S ribosomal subunits with 3 M NH4Cl/75 mM MgCl2 were able to prevent the ricin A chain-mediated inactivation of untreated 80 S rat liver ribosomes. The protection of polyphenylalanine synthetic capability of 80 S ribosomes was saturable and reached 100% protection in the presence of about 20 micrograms of extracted protein using a uniform set of assay conditions. No protection was observed using proteins extracted from wheat germ 40 S subunits or the core fraction of rat liver 60 S subunits or protein extracted from Escherichia coli ribosomes or ribosomal subunits. The conclusion that the protective effect of extracted 60 S subunit proteins was specific, was further strengthened by showing that unrelated proteins such as alpha-lactalbumin, bovine serum albumin and lysozyme, and polypeptides such as polylysine and poly(aspartic acid), also showed no protection. If 80 S ribosomes were first treated with ricin A chain and then incubated with proteins extracted from rat liver 60 S subunits, no protection was observed. Proteins extracted with NH4Cl/MgCl2 from 60 S rat liver subunits were applied to carboxymethylcellulose column equilibrated with 6 M urea. Stepwise elution with increasing concentrations of LiCl resulted in seven fractions. One fraction (D) contained most of the protective factor; one fraction (E) contained a lesser amount of the protective factor. Two-dimensional polyacrylamide gel electrophoresis of fraction D showed the presence of ten proteins. These data are consistent with the idea that the enzymatic target of ricin A chain is protein is nature and that fraction D contains one or more proteins that appear to act as a inhibitor against ricin A chain.


Assuntos
Cloreto de Amônio/farmacologia , Fígado/metabolismo , Magnésio/farmacologia , Proteínas Ribossômicas/fisiologia , Ribossomos/metabolismo , Ricina/farmacologia , Animais , Cinética , Fígado/efeitos dos fármacos , Cloreto de Magnésio , Lectinas de Plantas , Plantas/metabolismo , Biossíntese de Proteínas/efeitos dos fármacos , Ratos , Ribossomos/efeitos dos fármacos , Ribossomos/ultraestrutura , Triticum/metabolismo
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