RESUMO
Painful diagnostic and therapeutic procedures are common in the emergency department. Adequately treating pain, including the pain of procedures is an essential component of the practice of emergency medicine. Pain management is also part of the core competency for emergency medicine residencies and pediatric emergency medicine fellowships. There are many benefits to providing local and/or topical anesthesia before performing a medical procedure, including better patient and family satisfaction and increased procedural success rates. Local and topical anesthetics when used appropriately, generally, have few, if any, systemic side effects, such as hypotension or respiratory depression, which is an advantage over procedural sedation. Use of local and topical anesthetics can do much toward alleviating the pain and anxiety of pediatric patients undergoing procedures in the emergency department.
Assuntos
Anestésicos Locais , Medicina de Emergência , Manejo da Dor/métodos , Anestésicos Locais/uso terapêutico , Criança , Serviço Hospitalar de Emergência , Humanos , Dor , Medição da DorRESUMO
This paper presents an investigation of the reconstructibility of coherent X-ray diffractive imaging diffraction patterns for a class of binary random `bitmap' objects. Combining analytical results and numerical simulations, the critical fluence per bitmap pixel is determined, for arbitrary contrast values (absorption level and phase shift), both for the optical near- and far-field. This work extends previous investigations based on information theory, enabling a comparison of the amount of information carried by single photons in different diffraction regimes. The experimental results show an order-of-magnitude agreement.
Assuntos
Dor Aguda/diagnóstico , Guias de Prática Clínica como Assunto , Escroto , Torção do Cordão Espermático/diagnóstico , Triagem/métodos , Procedimentos Cirúrgicos Urológicos Masculinos/métodos , Dor Aguda/etiologia , Dor Aguda/cirurgia , Criança , Humanos , Masculino , Torção do Cordão Espermático/complicações , Torção do Cordão Espermático/cirurgiaRESUMO
BACKGROUND: The aim of the study was to examine whether the efficacy of psychoeducation in patients with schizophrenia is dependent on their cognitive performance and if a preceding cognitive training can enhance the therapeutic effects of psychoeducation. PATIENTS AND METHODS: A total of 116 inpatients were randomly assigned to either a standardized cognitive training (COGPACK) or to routine occupational therapy, followed by a psychoeducational group program of 8 sessions within 4 weeks for all study patients. The effects of cognitive training and psychoeducation were assessed directly afterwards and in a follow-up after 9 months. RESULTS: The patient knowledge and compliance improved. Neurocognition and especially memory acquisition significantly predicted illness knowledge after psychoeducation, whereas psychopathology did not. No differential effects of the COGPACK training were found. After 9 months 75% of the patients showed a very good compliance and the readmission rate was 18%. The results were comparable under both study conditions. CONCLUSION: Besides baseline illness knowledge neurocognition was the only significant predictor for illness knowledge after psychoeducation. Patients with cognitive deficits can profit from psychoeducation in the long run as well. In future it should be examined whether a modified cognitive training program could achieve a faster improvement of the illness knowledge.
Assuntos
Transtornos Cognitivos/terapia , Testes Neuropsicológicos/estatística & dados numéricos , Educação de Pacientes como Assunto/métodos , Psicoterapia/métodos , Esquizofrenia/terapia , Psicologia do Esquizofrênico , Terapia Assistida por Computador/métodos , Conscientização , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/epidemiologia , Transtornos Cognitivos/psicologia , Terapia Combinada , Comorbidade , Humanos , Cooperação do Paciente/psicologia , Cooperação do Paciente/estatística & dados numéricos , Readmissão do Paciente/estatística & dados numéricos , Prognóstico , Escalas de Graduação Psiquiátrica/estatística & dados numéricos , Psicometria , Esquizofrenia/diagnóstico , Esquizofrenia/epidemiologia , Resultado do TratamentoRESUMO
BACKGROUND: Many patients with schizophrenia exhibit neurocognitive impairments, namely, in attentional, mnestic and executive functions. While these deficits limit psychosocial rehabilitation, their effect on psychoeducation is unknown. Within the framework of the longitudinal Munich Cognitive Determinants of Psychoeducation and Information in Schizophrenic Psychoses (COGPIP) study, we examined: (a) whether illness knowledge after psychoeducation could be predicted more precisely from the neurocognitive than from the psychopathological status of the patients; (b) which neurocognitive domains are best predictors. METHOD: A total of 116 in-patients with schizophrenic or schizoaffective disorders were randomized to a neurocognitive training or control condition (2 weeks) followed by a manualized psychoeducational group programme (4 weeks) and then observed over a 9-month follow-up. Repeated measurements included - among others - the Positive and Negative Syndrome Scale and a comprehensive neuropsychological test battery from which normative T scores were used to calculate one global and five domain-specific neurocognitive composite scores. Illness knowledge was measured by a questionnaire (WFB-52) tailored to the psychoeducational programme. RESULTS: Multiple linear regression analyses showed that, apart from baseline illness knowledge, neurocognition significantly predicted knowledge outcome as well as knowledge gain (measured by reliable change indices) after psychoeducation. This was not true for psychopathology. Among the domain-specific neurocognitive composite scores, only memory acquisition was a significant predictor of knowledge outcome and gain. CONCLUSIONS: Neurocognition, not psychopathology, is a significant predictor of illness knowledge after psychoeducation in schizophrenia. This finding should guide efforts to tailor psychoeducational interventions more closely to the patient's needs and resources.
Assuntos
Educação de Pacientes como Assunto , Psicologia do Esquizofrênico , Adulto , Cognição , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Modelos Lineares , Masculino , Testes Neuropsicológicos , Esquizofrenia/terapia , Resultado do TratamentoRESUMO
Trauma is the leading cause of death in children nationwide. Proper management of the pediatric trauma patient involves many of the components contained within standard trauma protocols. By paying strict attention to the anatomical and physiological differences in the pediatric population, clinicians will be assured the best possible outcomes. This article outlines the fundamentals of proper management of pediatric trauma patients.
Assuntos
Ferimentos e Lesões/diagnóstico , Ferimentos e Lesões/terapia , Traumatismos Abdominais/diagnóstico , Traumatismos Abdominais/terapia , Adolescente , Criança , Pré-Escolar , Emergências , Humanos , Lactente , Intubação Intratraqueal , Monitorização Fisiológica , Pediatria , Exame Físico , Traumatismos Torácicos/diagnóstico , Traumatismos Torácicos/terapia , Traumatismos do Sistema Nervoso/diagnóstico , Traumatismos do Sistema Nervoso/terapiaRESUMO
Lubrication of the tooling (punches and dies) is necessary to produce tablets. The most commonly used lubricant is magnesium stearate. Adding and blending magnesium stearate to the tablet mass often has negative effects on the properties of the compressed tablets (e.g., decreasing the tensile strength of the tablet). To avoid these negative effects, external lubrication systems were developed. This study investigated the functionality and the influence of a new press chamber coating system called the PKB II. The major difference between the PKB II and previous systems is its ability to spray a mixture of powdered magnesium stearate and air directly onto the punches and dies which was determined to allow the running of the rotor at higher speeds. The data showed a clear correlation between the spray rate of the lubricant and the concentration of the magnesium stearate per tablet. The PKB II was designed to allow for adjustments, in order to optimize the spray rate, by using the ejection force. The concentration of magnesium stearate was reduced to approximately 0.04% per tablet, using the PKB II. Additionally, the most common negative effects, such as the decrease in tablet tensile strength, were avoided by using this system.
Assuntos
Composição de Medicamentos/instrumentação , Lubrificação , Calibragem , Desenho de Equipamento , Excipientes , Lactose/química , Manitol/química , Sorbitol/química , Espectrofotometria Atômica , Amido/química , Ácidos Esteáricos/análise , Comprimidos , Resistência à TraçãoRESUMO
OBJECTIVE: To assess whether alexithymia is a risk factor for exacerbation in spasmodic torticollis (ST). METHODS: ST patients (2 x 10) with high vs. low alexithymia scores (mean score on the 20-item Toronto Alexithymia Scale [TAS-20]=69.2 vs. 28.7) were compared on physiological, motor and subjective responses to a cognitive and an emotional laboratory stressor. Changes in sustained abnormal head/shoulder positions and maximum range of motion (ROM) of the cervical spine were kinematically quantified. Skin conductance level (SCL), nonspecific skin conductance fluctuations (NS.SCF), heart rate (HR) and skin temperature (T) were measured. RESULTS: High alexithymia had no effect on the abnormal head posture or movements, but high-alexithymic ST patients showed generally increased levels of autonomic arousal (more NS.SCF, higher SCL; analysis of variance [ANOVA]: P=.016 and P=.051, respectively) under all experimental conditions. When ST symptom severity (TSUI-score) was partialled out, these group differences were somewhat reduced (analysis of covariance [ANCOVA]: P=.052 and P=.143). CONCLUSIONS: High alexithymia did not lead to increased abnormal head movements to stressors, but may result in a subtle increase in tonic level of sympathetic activity.
Assuntos
Sintomas Afetivos/complicações , Sintomas Afetivos/psicologia , Torcicolo/etiologia , Torcicolo/psicologia , Adulto , Idoso , Sistema Nervoso Autônomo/fisiologia , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Índice de Gravidade de Doença , Fenômenos Fisiológicos da Pele , Temperatura Cutânea , Estresse PsicológicoRESUMO
Las hortalizas son las más importantes fuentes de transmisión parásitos a los seres humanos. El objetivo de este trabajo fue evaluar la ocurrencia de transmisión de parásitos en hortalizas producidas por productores rurales de Umuarama, Paraná, Brasil. La investigación analizó 133 muestras de hortalizas y 25 fueron positivas para algún parásito, entre estas 8/ 71 (el 8,4%) fueron de lechuga flamenca, 6/ 33 (el 18,2%) de lechuga lisa, 8/ 18 (el 44,4%) (almeirão este término no hay correspondiente en lengua española porque esta verdura es propria de clima tropical. Creo que lo mejor será dejarla en bastardilla {itálico} y si se quiere hacer una nota de pie de página) almeirón y 3/ 11 (27,3%) de achicoria. El análisis de las hortalizas evidenció helmintos en 23 (el 17,3%) y protozoarios en 6 (el 4,5%) de las 133 muestras. Los parásitos observados fueron Ascaris sp (el 9,7%), Ancilostomatidae (el 9,7%), Enterobius vermiculares (el 1,5%) y Strongyloides sp (el 1,5%) entre los helmintos y Entamoeba sp (el 3,7%) y Giardia sp (el 0,7%) entre los protozoarios. Estos datos demuestran la necesidad de realización de medidas preventivas sobre las hortalizas, por las autoridades sanitarias y consumidores, para disminuir el peligro de infección por parásitos a través de esta vía de transmisión.
Assuntos
Eucariotos , Produção Agrícola/estatística & dados numéricos , Helmintos/parasitologia , VerdurasRESUMO
BACKGROUND: CSF concentrations of tau and beta-amyloid protein-42 (Abeta42) have been extensively studied in AD. Few data are available concerning CSF levels of both proteins in patients with frontotemporal degeneration (FTD). METHODS: The authors investigated CSF tau and Abeta42 concentrations in 34 patients with FTD, 74 patients with AD, and 40 cognitively healthy control subjects. CSF levels of tau and Abeta42 were measured by ELISA. With use of receiver operating characteristic-derived cutoff points and linear discrimination lines, the diagnostic sensitivity and specificity of both markers were determined. RESULTS: CSF tau concentrations were significantly higher in FTD than in control subjects but were significantly lower than in AD. CSF Abeta42 levels were significantly lower in FTD than in control subjects but were significantly higher than in AD. In subjects with FTD, neither tau nor Abeta42 levels correlated with the severity of dementia. The best discrimination between the diagnostic groups was obtained by simultaneous measurement of tau and Abeta42, yielding a sensitivity of 90% at a specificity of 77% (FTD vs controls) and a sensitivity of 85% at a specificity of 85% (FTD vs AD). CONCLUSIONS: In FTD, CSF levels of tau are elevated and Abeta42 levels are decreased. With use of these markers, subjects with FTD can be distinguished from control subjects and from patients with AD with reasonable accuracy.
Assuntos
Peptídeos beta-Amiloides/líquido cefalorraquidiano , Demência/líquido cefalorraquidiano , Fragmentos de Peptídeos/líquido cefalorraquidiano , Proteínas tau/líquido cefalorraquidiano , Idoso , Doença de Alzheimer/líquido cefalorraquidiano , Doença de Alzheimer/patologia , Biomarcadores , Demência/patologia , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placa Amiloide/patologia , Sensibilidade e EspecificidadeRESUMO
B-CLL cells are arrested in G0/early G1 phase of the cell cycle and are characterized by a marked hyporesponsiveness towards a variety of polyclonal B cell activators. We have previously demonstrated that costimulation with CpG-ODN and IL-2 can overcome this proliferative defect. Cyclin D3 is the principal D-type cyclin which mediates G1 progression in normal B cells, but in B-CLL cells both cyclin D2 and cyclin D3, were strongly upregulated upon stimulation. Both cyclins were associated with cdk4 but not with cdk6, which is the catalytic partner of D-type cyclins in normal B cells. Moreover, immune complexes consisting of cyclin D2 and cdk4 or cyclin D3 and cdk4 were both functional and phosphorylated the RB protein in vitro. The cell cycle inhibitor p27 plays a pivotal role in cell cycle progression of B lymphocytes and has been shown to be overexpressed in B-CLL cells. P27 was rapidly downregulated in B-CLL cells even when stimulated with a non-CpG-ODN or IL-2 alone, while only moderate regulation could be observed in normal B cells. Taken together, our findings demonstrate that regulation of early cell cycle progression differs between B-CLL cells and normal B cells. These findings do not only contribute to the understanding of B-CLL pathophysiology, but might ultimately lead to the identification of new therapeutic targets.
Assuntos
Proteínas de Ciclo Celular/metabolismo , Ciclo Celular/fisiologia , Quinases Ciclina-Dependentes/metabolismo , Ciclinas/metabolismo , Leucemia Linfocítica Crônica de Células B/metabolismo , Proteínas Proto-Oncogênicas , Proteínas Supressoras de Tumor/metabolismo , Apoptose , Linfócitos B/efeitos dos fármacos , Linfócitos B/metabolismo , Ciclina D1/metabolismo , Ciclina D2 , Ciclina D3 , Quinase 4 Dependente de Ciclina , Inibidor de Quinase Dependente de Ciclina p27 , Primers do DNA/química , Combinação de Medicamentos , Citometria de Fluxo , Humanos , Immunoblotting , Interleucina-2/farmacologia , Oligodesoxirribonucleotídeos/farmacologia , Fosforilação , Testes de Precipitina , Proteína do Retinoblastoma/metabolismo , Timidina/metabolismo , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismoRESUMO
Grb4 is an adaptor protein consisting of three src homology (SH) 3 domains and a single SH2 domain. We previously cloned Grb4 as a direct interacting partner of Bcr-Abl and v-Abl via the Grb4 SH2 domain. We now show that overexpression of Grb4 results in significant inhibition of v-Abl-induced transcriptional activation from promitogenic enhancer elements such as activator protein 1 (AP-1) and serum-responsive element (SRE). We demonstrate that the inhibitory activity of Grb4 is independent of the direct interaction of v-Abl and Grb4: a Grb4 mutant that lacks a functional SH2 domain shows an even more pronounced inhibition of AP-1/SRE. Further mutational analysis revealed that the first two SH3 domains primarily mediate the inhibitory function. The inhibitory activity of Grb4 is specific for c-jun/c-fos-regulated promoter elements and is located downstream of MEKK1 and JNK because co-expression of Grb4 resulted in down-regulation of MEKK1-induced AP-1 activity without affecting JNK activity. Thus, the nuclear pool of Grb4 is likely to mediate this inhibition. Indeed, cell fractionation and fluorescence microscopy studies revealed that the stronger inhibitory potential of the Grb4 SH2 mutant occurred in conjunction with increased nuclear localization of this mutant. Our results suggest a novel role for Grb4 in the inhibition of promitogenic enhancer elements such as 12-O-tetradecanoylphorbol-13-acetate-responsive element and SRE.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Núcleo Celular/metabolismo , Proteínas Oncogênicas v-abl/metabolismo , Proteínas Oncogênicas/metabolismo , Proteínas Oncogênicas/fisiologia , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-jun/genética , Transcrição Gênica , Células 3T3 , Ágar/metabolismo , Animais , Células COS , Linhagem Celular , Citoplasma/metabolismo , Genes Reporter , Humanos , Immunoblotting , Camundongos , Mutação , Proteínas Oncogênicas/química , Testes de Precipitina , Ligação Proteica , Proteínas Recombinantes de Fusão/metabolismo , Retroviridae/genética , Elemento de Resposta Sérica/genética , Acetato de Tetradecanoilforbol/farmacologia , Ativação Transcricional , Transfecção , Domínios de Homologia de srcRESUMO
P-type ATPases convert chemical energy into electrochemical gradients that are used to energize secondary active transport. Analysis of the structure and function of P-type ATPases has been limited by the lack of active recombinant ATPases in quantities suitable for crystallographic studies aiming at solving their three-dimensional structure. We have expressed Arabidopsis thaliana plasma membrane H+-ATPase isoform AHA2, equipped with a His(6)-tag, in the yeast Saccharomyces cerevisiae. The H+-ATPase could be purified both in the presence and in the absence of regulatory 14-3-3 protein depending on the presence of the diterpene fusicoccin which specifically induces formation of the H+-ATPase/14-3-3 protein complex. Amino acid analysis of the purified complex suggested a stoichiometry of two 14-3-3 proteins per H+-ATPase polypeptide. The purified H(+)-ATPase readily formed two-dimensional crystals following reconstitution into lipid vesicles. Electron cryo-microscopy of the crystals yielded a projection map at approximately 8 A resolution, the p22(1)2(1) symmetry of which suggests a dimeric protein complex. Three distinct regions of density of approximately equal size are apparent and may reflect different domains in individual molecules of AHA2.
Assuntos
Arabidopsis/enzimologia , Membrana Celular/enzimologia , Microscopia Crioeletrônica , ATPases Translocadoras de Prótons/química , ATPases Translocadoras de Prótons/isolamento & purificação , Proteínas 14-3-3 , Arabidopsis/genética , Cristalização , Dimerização , Glicosídeos/farmacologia , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/isolamento & purificação , Isoenzimas/ultraestrutura , Lipossomos/química , Lipossomos/metabolismo , Ligação Proteica/efeitos dos fármacos , Estrutura Quaternária de Proteína , ATPases Translocadoras de Prótons/genética , ATPases Translocadoras de Prótons/metabolismo , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/genética , Relação Estrutura-Atividade , Tirosina 3-Mono-Oxigenase/química , Tirosina 3-Mono-Oxigenase/isolamento & purificação , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Two-dimensional crystals of a membrane protein, the proton ATPase from plant plasma membranes, have been obtained by a new strategy based on the use of functionalized, fluorinated lipids spread at the air-water interface. Monolayers of the fluorinated lipids are stable even in the presence of high concentrations of various detergents as was established by ellipsometry measurements. A nickel functionalized fluorinated lipid was spread into a monolayer at the air-water interface. The overexpressed His-tagged ATPase solubilized by detergents was added to the subphase. 2D crystals of the membrane protein, embedded in a lipid bilayer, formed as the detergent was removed by adsorption. Electron microscopy indicated that the 2D crystals were single layers with dimensions of 10 microm or more. Image processing yielded a projection map at 9 A resolution, showing three well-separated domains of the membrane-embedded proton ATPase.
Assuntos
Microscopia Crioeletrônica , Detergentes/metabolismo , Metabolismo dos Lipídeos , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Membranas Artificiais , Adsorção , Ar , Arabidopsis/química , Arabidopsis/enzimologia , Quelantes/síntese química , Quelantes/química , Quelantes/metabolismo , Cristalização , Detergentes/farmacologia , Flúor/metabolismo , Processamento de Imagem Assistida por Computador , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Lipídeos/síntese química , Lipídeos/química , Proteínas de Membrana/ultraestrutura , Micelas , Níquel/antagonistas & inibidores , Níquel/metabolismo , Pressão , Ligação Proteica , Estrutura Terciária de Proteína , ATPases Translocadoras de Prótons/química , ATPases Translocadoras de Prótons/metabolismo , ATPases Translocadoras de Prótons/ultraestrutura , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/ultraestrutura , Solubilidade/efeitos dos fármacos , Água/metabolismoAssuntos
Atenção , Sinais (Psicologia) , Fenômenos Eletromagnéticos/métodos , Extinção Psicológica , Transtornos da Percepção/fisiopatologia , Transtornos da Percepção/terapia , Córtex Somatossensorial/metabolismo , Córtex Somatossensorial/fisiopatologia , Tato , Adulto , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos da Percepção/diagnóstico , Propriocepção/fisiologia , Índice de Gravidade de Doença , Tomografia Computadorizada de EmissãoRESUMO
Despite its frequency in right brain damaged patients crucial mechanisms of tactile extinction are still obscure and treatments are unavailable. Recent PET observations suggest a hypometabolism in the primary and secondary somatosensory cortex of the lesioned hemisphere in patients with tactile extinction. Functional and morphological investigations have shown that the sensorimotor cortex has a remarkable capability of reorganization when the sensory inflow is changed. Repetitive peripheral magnetic stimulation (RPMS) applied in patients suffering from central paresis alleviates sensorimotor as well as cognitive deficits by the induction of proprioceptive inflow, thereby activating plasticity in the CNS. Based on the observation of reduced metabolic activity in patients suffering from tactile extinction we applied RPMS to explore the effects of peripheral sensory stimulation on tactile extinction. Fourteen right-hemisphere lesioned patients with tactile extinction were randomly allocated to an experimental and a control group. The experimental group received one single RPMS treatment of the left forearm as well as a condition of attentional cueing known to improve visual extinction. The control group, with comparable tactile extinction scores, neither received RPMS nor verbal cueing, but was tested twice to evaluate possible learning or test repetition effects. In the experimental group RPMS led to a significant reduction of left-sided extinctions in the recognition of different tactual surfaces, but had no effect on ipsilesional errors. In contrast, attentional cueing had no significant effect on left-sided extinction errors but unexpectedly increased right-hand extinction errors slightly but significantly. The control group showed stable extinction scores of the left- and right-hand stimulus across two measurements, thus ruling out learning or test repetition effects. These results show that sensory inflow is an important modulatory factor in tactile extinction. Furthermore, multiple RPMS may prove a promising way for the rehabilitation of patients with this disorder.
Assuntos
Lesões Encefálicas/complicações , Córtex Cerebral/fisiopatologia , Extinção Psicológica/fisiologia , Magnetismo/uso terapêutico , Distúrbios Somatossensoriais/fisiopatologia , Adulto , Idoso , Atenção/fisiologia , Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Córtex Cerebral/patologia , Terapia por Estimulação Elétrica , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos da Percepção/patologia , Transtornos da Percepção/fisiopatologia , Transtornos da Percepção/terapia , Periodicidade , Nervos Periféricos/fisiologia , Desempenho Psicomotor/fisiologia , Distúrbios Somatossensoriais/patologia , Tato/fisiologiaRESUMO
We report here the characterization of an adapter protein identified in a yeast 2-hybrid screen with the use of Bcr-Abl as the bait. Grb4 bound to Bcr-Abl in a variety of systems, both in vitro and in vivo, and is an excellent substrate of the Bcr-Abl tyrosine kinase. The association of Grb4 and Bcr-Abl in intact cells was mediated by an src homology (SH)2-mediated phosphotyrosine-dependent interaction as well as an SH3-mediated phosphotyrosine-independent interaction. Grb4 has 68% homology to the adapter protein Nck and has similar but distinct binding specificities in K562 lysates. Subcellular localization studies indicate that Grb4 localizes to both the nucleus and the cytoplasm. Coexpression of kinase-active Bcr-Abl with Grb4 resulted in the translocation of Grb4 from the cytoplasm and the nucleus to the cytoskeleton to colocalize with Bcr-Abl. In addition, expression of Grb4 with kinase-active Bcr-Abl resulted in a redistribution of actin-associated Bcr-Abl. Finally, coexpression of Grb4 and oncogenic v-Abl strongly inhibited v-Abl-induced AP-1 activation. Together, these data indicate that Grb4 in conjunction with Bcr-Abl may be capable of modulating the cytoskeletal structure and negatively interfering with the signaling of oncogenic Abl kinases. Grb4 may therefore play a role in the molecular pathogenesis of chronic myelogenous leukemia. (Blood. 2000;96:618-624) (Blood. 2000;96:618-624)
Assuntos
Proteínas de Fusão bcr-abl/metabolismo , Proteínas Oncogênicas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Animais , Células COS , Núcleo Celular/metabolismo , Clonagem Molecular , Glutationa Transferase , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/farmacologia , Proteínas Oncogênicas v-abl/farmacologia , Fragmentos de Peptídeos/genética , Fosforilação , Fosfotirosina/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Fator de Transcrição AP-1/metabolismoRESUMO
14-3-3 proteins play a regulatory role in a diverse array of cellular functions such as apoptosis, regulation of the cell cycle, and regulation of gene transcription. The phytotoxin fusicoccin specifically induces association of virtually any 14-3-3 protein to plant plasma membrane H(+)-ATPase. The 14-3-3 binding site in the Arabidopsis plasma membrane H(+)-ATPase AHA2 was localized to the three C-terminal residues of the enzyme (Tyr(946)-Thr-Val). Binding of 14-3-3 protein to this target was induced by phosphorylation of Thr(947) (K(D) = 88 nM) and was in practice irreversible in the presence of fusicoccin (K(D) = 7 nM). Mass spectrometry analysis demonstrated that AHA2 expressed in yeast was phosphorylated at Thr(947). We conclude that the extreme end of AHA2 contains an unusual high-affinity binding site for 14-3-3 protein.
Assuntos
Arabidopsis/metabolismo , Proteínas/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Transdução de Sinais , Tirosina 3-Mono-Oxigenase , Proteínas 14-3-3 , Sequência de Aminoácidos , Membrana Celular/metabolismo , Dados de Sequência Molecular , Fosforilação , Treonina , Tirosina , ValinaRESUMO
The plasma membrane H+-ATPase is a proton pump belonging to the P-type ATPase superfamily and is important for nutrient acquisition in plants. The H+-ATPase is controlled by an autoinhibitory C-terminal regulatory domain and is activated by 14-3-3 proteins which bind to this part of the enzyme. Alanine-scanning mutagenesis through 87 consecutive amino acid residues was used to evaluate the role of the C-terminus in autoinhibition of the plasma membrane H+-ATPase AHA2 from Arabidopsis thaliana. Mutant enzymes were expressed in a strain of Saccharomyces cerevisiae with a defective endogenous H+-ATPase. The enzymes were characterized by their ability to promote growth in acidic conditions and to promote H+ extrusion from intact cells, both of which are measures of plasma membrane H+-ATPase activity, and were also characterized with respect to kinetic properties such as affinity for H+ and ATP. Residues that when altered lead to increased pump activity group together in two regions of the C-terminus. One region stretches from K863 to L885 and includes two residues (Q879 and R880) that are conserved between plant and fungal H+-ATPases. The other region, incorporating S904 to L919, is situated in an extension of the C-terminus unique to plant H+-ATPases. Alteration of residues in both regions led to increased binding of yeast 14-3-3 protein to the plasma membrane of transformed cells. Taken together, our data suggest that modification of residues in two regions of the C-terminal regulatory domain exposes a latent binding site for activatory 14-3-3 proteins.
Assuntos
Arabidopsis/enzimologia , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Mapeamento de Peptídeos , ATPases Translocadoras de Prótons/antagonistas & inibidores , ATPases Translocadoras de Prótons/metabolismo , Proteínas de Saccharomyces cerevisiae , Tirosina 3-Mono-Oxigenase , Proteínas 14-3-3 , Sequência de Aminoácidos , Substituição de Aminoácidos/genética , Arabidopsis/genética , Membrana Celular/enzimologia , Ativação Enzimática/genética , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Cinética , Dados de Sequência Molecular , Mutagênese Insercional , Mutagênese Sítio-Dirigida , Fragmentos de Peptídeos/fisiologia , Proteínas/metabolismo , Proteínas/fisiologia , ATPases Translocadoras de Prótons/genética , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genéticaRESUMO
From the dichloromethane extract of the tropical marine sponge Strepsichordaia lendenfeldi collected from the Great Barrier Reef, Australia, three new (1, 2, and 9) and seven known (3-8 and 10) scalarane-based sesterterpenes were isolated. All molecular structures were secured by spectroscopic methods, particularly 1D and 2D NMR, and accurate mass measurement.