Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
Radiography (Lond) ; 30(2): 582-588, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38310658

RESUMO

INTRODUCTION: The breathing and suspended inspiration techniques are often used interchangeably for spine X-ray examinations. However, these techniques are not always adequately supported by clinical evidence. This study aimed to determine the two techniques' diagnostic value and adverse image outcomes. METHODS: A total of 400 participants were examined on a Siemens Ysio Max system and randomized into four examination groups: suspended inspiration or breathing techniques with exposure times of 1, 2, and 3.2 s, respectively. Two consultant radiologists conducted the evaluation of the X-ray images. If disagreement was present, the radiologists collaboratively reviewed the X-ray images until a consensus was reached. RESULTS: The final 394 study population comprised 275 women and 119 men with a mean age of 64 years (range:18-96 years). The proportions of visually sharp reproduction of the endplates and trabecular structures did not differ significantly with regards to differences in exposure times between groups. The breathing technique groups had significantly higher proportions of blurring and motion artifacts (p < 0.001). However, adverse image outcomes (motions artifacts) were significantly lower in the 1-s exposure group. CONCLUSIONS: The suspended inspiration and breathing techniques performed equally well regarding visually sharp reproduction. However, the suspended inspiration technique was superior to the breathing technique. regarding adverse image outcomes, although the latter could be improved by using a shorter exposure time. IMPLICATIONS FOR PRACTICE: The suspended inspiration and breathing technique appeared to perform at equal diagnostic levels. The suspended inspiration technique should be preferred due to its reduced risk of adverse image outcomes. However, the risk could also be reduced using a short exposure time with the breathing technique.


Assuntos
Respiração , Tomografia Computadorizada por Raios X , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor nas Costas/diagnóstico por imagem , Radiografia , Tomografia Computadorizada por Raios X/métodos , Raios X , Adolescente , Adulto Jovem , Adulto , Idoso , Idoso de 80 Anos ou mais
2.
Nano Lett ; 22(13): 5365-5371, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35699569

RESUMO

Time-resolved optical measurements of vibrating metal nanoparticles have been used extensively to probe the ultrafast mechanical properties of the nanoparticles and of the surrounding liquid, but nearly all investigations so far have been limited to the linear regime. Here, we report the observation of a low-frequency oscillating signal in transient-absorption measurements of nanoparticles with octahedral gold cores and cubic silver shells; the signal appears at the difference of two mechanical vibrational frequencies in the particles, suggesting a nonlinear mixing process. We tentatively attribute this proposed mixing to a nonlinear coupling between a vibrational mode of the nanoparticle and its optical-frequency plasmon resonance. The optimization of this nonlinear transduction may enable high-efficiency opto-mechanical frequency mixing in the GHz-THz frequency regime.


Assuntos
Nanopartículas Metálicas , Vibração , Ouro
3.
Tech Coloproctol ; 26(5): 333-349, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35192122

RESUMO

BACKGROUND: Hospital readmissions after creation of an ileostomy are common and come with a high clinical and financial burden. The aim of this review with pooled analysis was to determine the incidence of dehydration-related and all-cause readmissions after formation of an ileostomy, and the associated costs. METHODS: A systematic literature search was conducted for studies reporting on dehydration-related and overall readmission rates after formation of a loop or end ileostomy between January 1990 and April 2021. Analyses were performed using R Statistical Software Version 3.6.1. RESULTS: The search yielded 71 studies (n = 82,451 patients). The pooled incidence of readmissions due to dehydration was 6% (95% CI 0.04-0.09) within 30 days, with an all-cause readmission rate of 20% (CI 95% 0.18-0.23). Duration of readmissions for dehydration ranged from 2.5 to 9 days. Average costs of dehydration-related readmission were between $2750 and $5924 per patient. Other indications for readmission within 30 days were specified in 15 studies, with a pooled incidence of 5% (95% CI 0.02-0.14) for dehydration, 4% (95% CI 0.02-0.08) for stoma outlet problems, and 4% (95% CI 0.02-0.09) for infections. CONCLUSIONS: One in five patients are readmitted with a stoma-related complication within 30 days of creation of an ileostomy. Dehydration is the leading cause for these readmissions, occurring in 6% of all patients within 30 days. This comes with high health care cost for a potentially avoidable cause. Better monitoring, patient awareness and preventive measures are required.


Assuntos
Ileostomia , Readmissão do Paciente , Desidratação/epidemiologia , Desidratação/etiologia , Desidratação/prevenção & controle , Humanos , Ileostomia/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Fatores de Risco
4.
J Chem Phys ; 154(10): 104305, 2021 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-33722049

RESUMO

Vibrational strong coupling of molecules to optical cavities based on plasmonic resonances has been explored recently because plasmonic near-fields can provide strong coupling in sub-diffraction limited volumes. Such field localization maximizes coupling strength, which is crucial for modifying the vibrational response of molecules and, thereby, manipulating chemical reactions. Here, we demonstrate an angle-independent plasmonic nanodisk substrate that overcomes limitations of traditional Fabry-Pérot optical cavities because the design can strongly couple with all molecules on the surface of the substrate regardless of molecular orientation. We demonstrate that the plasmonic substrate provides strong coupling with the C=O vibrational stretch of deposited films of PMMA. We also show that the large linewidths of the plasmon resonance allow for simultaneous strong coupling to two, orthogonal water symmetric and asymmetric vibrational modes in a thin film of copper sulfate monohydrate deposited on the substrate surface. A three-coupled-oscillator model is developed to analyze the coupling strength of the plasmon resonance with these two water modes. With precise control over the nanodisk diameter, the plasmon resonance is tuned systematically through the modes, with the Rabi splitting from both modes varying as a function of the plasmon frequency and with strong coupling to both modes achieved simultaneously for a range of diameters. This work may aid further studies into manipulation of the ground-state chemical landscape of molecules by perturbing multiple vibrational modes simultaneously and increasing the coupling strength in sub-diffraction limited volumes.

5.
Nanoscale ; 13(8): 4687, 2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33616135

RESUMO

Correction for 'Strong coupling of emitters to single plasmonic nanoparticles: exciton-induced transparency and Rabi splitting' by Matthew Pelton et al., Nanoscale, 2019, 11, 14540-14552, DOI: 10.1039/C9NR05044B.

6.
Nano Lett ; 21(4): 1599-1605, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33306403

RESUMO

Monolayer transition metal dichalcogenides, coupled to metal plasmonic nanocavities, have recently emerged as new platforms for strong light-matter interactions. These systems are expected to have nonlinear-optical properties that will enable them to be used as entangled photon sources, compact wave-mixing devices, and other elements for classical and quantum photonic technologies. Here, we report the first experimental investigation of the nonlinear properties of these strongly coupled systems, by observing second harmonic generation from a WSe2 monolayer strongly coupled to a single gold nanorod. The pump-frequency dependence of the second-harmonic signal displays a pronounced splitting that can be explained by a coupled-oscillator model with second-order nonlinearities. Rigorous numerical simulations utilizing a nonperturbative nonlinear hydrodynamic model of conduction electrons support this interpretation and reproduce experimental results. Our study thus lays the groundwork for understanding the nonlinear properties of strongly coupled nanoscale systems.

7.
Nanoscale ; 11(31): 14540-14552, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31364684

RESUMO

Strong coupling between plasmons in metal nanoparticles and single excitons in molecules or semiconductor nanomaterials has recently attracted considerable experimental effort for potential applications in quantum-mechanical and classical optical information processing and for fundamental studies of light-matter interaction. Here, we review the theory behind strong plasmon-exciton coupling and provide analytical expressions that can be used for fitting experimental data, particularly the commonly measured scattering spectra. We re-analyze published data using these expressions, providing a uniform method for evaluating and quantifying claims of strong coupling that avoids ambiguities in distinguishing between Rabi splitting and exciton-induced transparency (or Fano-like interference between plasmons and excitons).

8.
Nature ; 476(7361): 425-8, 2011 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-21866155

RESUMO

Active galactic nuclei, which are powered by long-term accretion onto central supermassive black holes, produce relativistic jets with lifetimes of at least one million years, and the observation of the birth of such a jet is therefore unlikely. Transient accretion onto a supermassive black hole, for example through the tidal disruption of a stray star, thus offers a rare opportunity to study the birth of a relativistic jet. On 25 March 2011, an unusual transient source (Swift J164449.3+573451) was found, potentially representing such an accretion event. Here we report observations spanning centimetre to millimetre wavelengths and covering the first month of evolution of a luminous radio transient associated with Swift J164449.3+573451. The radio transient coincides with the nucleus of an inactive galaxy. We conclude that we are seeing a newly formed relativistic outflow, launched by transient accretion onto a million-solar-mass black hole. A relativistic outflow is not predicted in this situation, but we show that the tidal disruption of a star naturally explains the observed high-energy properties and radio luminosity and the inferred rate of such events. The weaker beaming in the radio-frequency spectrum relative to γ-rays or X-rays suggests that radio searches may uncover similar events out to redshifts of z ≈ 6.

9.
Allergol Immunopathol (Madr) ; 33(1): 7-14, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15777517

RESUMO

BACKGROUND: Specific immunotherapy for hymenoptera venom allergy (venom immunotherapy [VIT]) is safe and effective. The duration of treatment is still open for discussion because there is no reliable routine test to determine the real risk of serious anaphylactic reactions. This prospective study, which spans more than 25 years, was conducted to ensure unlimited protection through continuous VIT. To reduce workload and cost, the maintenance interval was increased to 6 months without increasing the rate of adverse events. Only patients with continuous follow-up by our service were included in this study. PATIENTS AND METHODS: VIT was conducted in 176 patients (125 allergic to wasp venom, 20 to bee venom, 31 to both) over a mean of 7.14 years (1.16-25.49). Total and specific IgE were determined on a regular basis. RESULTS: A total of 162 re-stings were reported. Of these, 154 produced a strictly local reaction, seven produced non-serious reactions and one produced a systemic reaction similar to that produced by the initial sting before VIT. Total and specific IgE diminished during VIT. Substantial adverse effects were rare and never life-threatening. The effects occurred during observation in the ward and were controlled according to the treatment protocol recommended by a German expert consensus meeting on the treatment of anaphylactoid reactions. VIT was terminated in only one patient due to recurrent adverse effects. CONCLUSION: Continuous VIT at 6-monthly maintenance intervals conferred permanent protection in patients allergic to bee and wasp venoms and was found to be a safe and effective alternative to current standard protocols.


Assuntos
Anafilaxia/prevenção & controle , Venenos de Abelha/uso terapêutico , Dessensibilização Imunológica/métodos , Mordeduras e Picadas de Insetos/complicações , Venenos de Vespas/uso terapêutico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anafilaxia/etiologia , Animais , Venenos de Abelha/efeitos adversos , Venenos de Abelha/imunologia , Esquema de Medicação , Feminino , Humanos , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Mordeduras e Picadas de Insetos/imunologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Risco , Venenos de Vespas/efeitos adversos , Venenos de Vespas/imunologia
10.
Allergol. immunopatol ; 33(1): 7-14, ene. 2005. tab
Artigo em En | IBECS | ID: ibc-037691

RESUMO

Background: Specific immunotherapy for hymenoptera venom allergy (venom immunotherapy [VIT]) is safe and effective. The duration of treatment is still open for discussion because there is no reliable routine test to determine the real risk of serious anaphylactic reactions. This prospective study, which spans more than 25 years, was conducted to ensure unlimited protection through continuous VIT. To reduce workload and cost, the maintenance interval was increased to 6 months without increasing the rate of adverse events. Only patients with continuous follow-up by our service were included in this study. Patients and methods: VIT was conducted in 176 patients (125 allergic to wasp venom, 20 to bee venom, 31 to both) over a mean of 7.14 years (1.16-25.49). Total and specific IgE were determined on a regular basis. Results: A total of 162 re-stings were reported. Of these, 154 produced a strictly local reaction, seven produced non-serious reactions and one produced a systemic reaction similar to that produced by the initial sting before VIT. Total and specific IgE diminished during VIT. Substantial adverse effects were rare and never life-threatening. The effects occurred during observation in the ward and were controlled according to the treatment protocol recommended by a German expert consensus meeting on the treatment of anaphylactoid reactions. VIT was terminated in only one patient due to recurrent adverse effects. Conclusion: Continuous VIT at 6-monthly maintenance intervals conferred permanent protection in patients allergic to bee and wasp venoms and was found to be a safe and effective alternative to current standard protocols


Antecedentes: La inmunoterapia al veneno de hymenopteros (ITVH) se considera segura y eficaz. La discusión sobre la duración del tratamiento está todavía abierta dado que no existe un método fiable para determinar el riesgo real de reacción anafiláctica grave. Este estudio prospectivo que abarca un periodo de 25 años, se llevó a cabo para asegurar la protección ilimitada de la ITVH con el intervalo entre dosis ampliado a 6 meses, que disminuía costes y esfuerzos y sin incremento del índice de reacciones adversas. Únicamente se incluyeron en el estudio a pacientes de nuestro servicio en fase de seguimiento. Pacientes y métodos: La inmunoterapia frente a venenos se llevó a cabo en 176 pacientes (125 alérgicos al veneno de avispa, 20 al veneno de abeja y 31 a ambos) durante una media de 7,14 años (1,16-25,49). La IgE, total y específica, se determinó de forma habitual. Resultados: Se comunicaron un total de 162 re-pi-caduras, 154 de ellas con reacciones estrictamente locales, 7 con reacciones menos que intensas y sólo 1 con una reacción comparable a la primera picadura antes de la ITVH. Tanto la IgE total como específica disminuyeron durante la ITVH. Lo importante sobre los efectos secundarios es que fueron poco habituales y nunca amenazaron la vida de los pacientes. Las reacciones se presentaron durante el periodo de observación en el servicio y se trataron según el protocolo recomendado por un grupo de expertos de Alemania tras una reunión de consenso sobre reacciones anafilácticas. Sólo 1 paciente abandonó el tratamiento con ITVH por repetidos efectos adversos. Conclusión: Se demostró una protección permanente en pacientes alérgicos al veneno de abeja y/o avispa con una inmunoterapia de continuación frente a venenos, administrada a intervalos de 6 meses que se consideró una alternativa segura y eficaz a los actuales protocolos utilizados de forma estándar


Assuntos
Masculino , Feminino , Adulto , Idoso , Idoso de 80 Anos ou mais , Humanos , Anafilaxia/prevenção & controle , Venenos de Abelha/uso terapêutico , Dessensibilização Imunológica/métodos , Mordeduras e Picadas de Insetos/complicações , Venenos de Vespas/uso terapêutico , Anafilaxia/etiologia , Venenos de Abelha/efeitos adversos , Venenos de Abelha/imunologia , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Mordeduras e Picadas de Insetos/imunologia , Estudos Prospectivos
11.
Muscle Nerve ; 27(5): 631-5, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12707986

RESUMO

Tourniquet paralysis is an uncommon complication of surgery, and self-inflicted tourniquet paralysis has never been documented to our knowledge. We report a patient with bilateral self-induced tourniquet paralysis of the lower extremities, whose symptoms were initially attributed to an acute demyelinating sensorimotor polyneuropathy based on clinical presentation and electrodiagnostic study. After investigations failed to reveal a cause, he was found to have placed tourniquets on his legs because of a rare obsession with limb amputation known as apotemnophilia. Significant spontaneous partial resolution of clinical symptoms was noted after 6 weeks. Electrophysiologic evidence of segmental demyelination of multiple motor nerves localized to the same region may help to distinguish this condition from other forms of acute demyelinating polyneuropathy.


Assuntos
Doenças Desmielinizantes/diagnóstico , Paralisia/diagnóstico , Paralisia/etiologia , Comportamento Autodestrutivo/complicações , Torniquetes/efeitos adversos , Doença Aguda , Adulto , Amputação Cirúrgica/psicologia , Diagnóstico Diferencial , Eletrodiagnóstico , Humanos , Masculino , Condução Nervosa , Comportamento Obsessivo/complicações , Comportamento Obsessivo/psicologia , Paralisia/psicologia , Comportamento Autodestrutivo/diagnóstico , Comportamento Autodestrutivo/psicologia
12.
Brain Res Mol Brain Res ; 71(1): 50-60, 1999 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-10407186

RESUMO

Whole-cell [(32)P]-protein phosphorylation assays and two-dimensional gel electrophoresis (2-DGE) were applied to the analysis of the beta-adrenoceptor (betaAR)-linked signal transduction pathway. Rat C6 glioma cells were stimulated with isoproterenol and the protein lysates were resolved by 2-DGE. Two dimensional [(32)P]-phosphoprotein 'maps' were generated depicting the modulation of intracellular proteins after isoproterenol stimulation versus unstimulated cells. A total of 274 distinct phosphoprotein spots were detected, of which 200 were up-regulated, 69 were down-regulated, and 5 remained unchanged. An evaluation of isoproterenol's activity across several kinase pathways was performed using a computer-generated 2-DGE template incorporating the location and identification of individual signaling phosphoprotein intermediaries. The template served as a 'reference map' for drug treatment comparisons. We observed a significant increase in the phosphorylation states of several nuclear transcription factors, notably CREB-1, ATF-1, NFkappaB/IkappaBalpha and ELK-1, but not c-Jun. A parallel series of radioimmunoprecipitation studies confirmed our 2-DGE findings. Moreover, isoproterenol increased the phosphorylation state of PKC and of several MAPK-dependent pathway kinases which correlated with a significant increase in their endogenous kinase activity. Isoproterenol's effects on PKA, PKC and ERK-dependent activities were blocked by propranolol, a betaAR antagonist. In conclusion, an acute isoproterenol stimulus induced multiplex pathway modulation via the betaAR in the C6 glioma cell indicating that signaling pathway cross-talk is an essential feature for the regulation of cellular function. Moreover, the immediate advantages of the 2-DGE analytical approach were apparent, and further development of the protein database will provide a valuable tool to screen for broad-based drug-mediated signaling activities.


Assuntos
Isoproterenol/farmacologia , Fosfoproteínas/metabolismo , Proteína Quinase C/metabolismo , Receptores Adrenérgicos beta/fisiologia , Transdução de Sinais/efeitos dos fármacos , Fatores de Transcrição/metabolismo , Animais , Neoplasias Encefálicas , AMP Cíclico/metabolismo , Eletroforese em Gel Bidimensional/métodos , Glioma , Cinética , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas de Neoplasias/isolamento & purificação , Proteínas de Neoplasias/metabolismo , Fosfoproteínas/isolamento & purificação , Fosforilação , Propranolol/farmacologia , Ratos , Receptores Adrenérgicos beta/efeitos dos fármacos , Fatores de Transcrição/isolamento & purificação , Células Tumorais Cultivadas
13.
Neuroreport ; 5(5): 629-31, 1994 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-7912962

RESUMO

Glutamate toxicity in retinal ganglion cells has well documented both in vitro and in vivo, and has been suggested to play a role in the neuronal loss in glaucoma. Of note, glaucoma selectively damages larger retinal ganglion cells first, and we therefore sought to explore whether glutamate-mediated cell death was likewise more pronounced in larger retinal ganglion cells. We now report that glutamate--which exerts its toxic effect on neurons predominantly through the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor--is more toxic to larger retinal ganglion cells both in tissue culture and in the intact rat eye. Cells smaller than 10 microns were relatively unaffected by glutamate or NMDA. These agents are, however, markedly toxic to retinal ganglion cells larger than 10 microns. These observations indicate that glutamate-mediated loss is seen first in larger retinal ganglion cells, in a similar fashion to the pattern of loss seen in glaucoma.


Assuntos
N-Metilaspartato/toxicidade , Células Ganglionares da Retina/efeitos dos fármacos , Animais , Morte Celular , Tamanho Celular , Resistência a Medicamentos , Glutamatos/toxicidade , Ácido Glutâmico , Ratos , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Células Ganglionares da Retina/ultraestrutura
14.
Toxicol Lett ; 67(1-3): 201-10, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8451761

RESUMO

We demonstrate here consistent point mutations of the c-raf-1 proto-oncogene, within a small region of the kinase domain, in a mouse model for chemical tumor induction. This is the first demonstration of point mutated raf genes in vivo, and the first isolation of activating in vivo point mutations in the kinase domain of a proto-oncogene. The specific region where these mutations are clustered also has biological significance. This is precisely the region where 5/5 independently generated monoclonal antibodies raised against Raf-1 map to [29], and predictions based upon the crystal structure of A kinase identify this as the substrate pocket. The tumors examined show a selective specificity for Raf-1 mutations in that another family of genes, the ras proto-oncogenes which are frequently activated by point mutation in both animal and human tumors [15-21,26], is not involved. Our consistent finding of Raf-1 mutations in a mouse tumor model also has consequences for further evaluation of the role of Raf-1 in human tumor development, as it emphasizes the need to examine c-raf-1 at the sequence level. In fact preliminary screening of human lung tumors indicates point mutations at amino acid 533 (John Lyons, personal communication). Finally, the cumulative data on the critical role of Raf-1 in signal transduction and the occurrence of oncogenic Raf-1 in tumors [32-41] highlight this enzyme as an attractive target for development of novel anticancer regimens.


Assuntos
Mutação , Neoplasias Experimentais/genética , Neoplasias/genética , Oncogenes/genética , Animais , Hidroxitolueno Butilado , Cruzamentos Genéticos , Análise Mutacional de DNA , Etilnitrosoureia , Regulação Neoplásica da Expressão Gênica , Genes ras , Humanos , Neoplasias Pulmonares/genética , Camundongos , Camundongos Endogâmicos AKR , Família Multigênica , Neoplasias Experimentais/química , Mutação Puntual , Proto-Oncogene Mas
15.
Artigo em Alemão | MEDLINE | ID: mdl-1441689

RESUMO

The Vanderbilt-Psychotherapy-Scales appeared to be useful instruments for the identification of process characteristics determining the outcome of brief dynamic psychotherapies. The German versions of the two scales measuring important components of the psychotherapeutic process and of negative indicators are described in this article. It could be shown that--similar to the original versions--both scales can be used economically and that rater agreement soon reaches satisfactory levels. To demonstrate the potential use of the scales, their application in two different short term treatments are described which are presently analysed in a multi-center study of "single case oriented process research" using a variety of different methods. The example demonstrates that both scales are useful to discriminate both different theoretical foundations of the treatments as well as specific features of the patients and their therapists. The usefulness of the scales in a broader context is mainly based upon the experience that they reveal a lot of important informations about the psychotherapeutic process with a minimum of expense.


Assuntos
Desenvolvimento da Personalidade , Inventário de Personalidade/estatística & dados numéricos , Terapia Psicanalítica , Psicoterapia Breve , Transtornos de Ansiedade/psicologia , Transtornos de Ansiedade/terapia , Seguimentos , Humanos , Masculino , Transtorno Obsessivo-Compulsivo/psicologia , Transtorno Obsessivo-Compulsivo/terapia , Avaliação de Processos e Resultados em Cuidados de Saúde , Relações Médico-Paciente , Psicometria
16.
Oncogene ; 5(3): 345-51, 1990 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1690378

RESUMO

We have determined RNA expression patterns of raf family proto-oncogenes in a variety of normal NFS/n mouse tissues, and several murine cell lines. Tissues were collected from male and female adults, and 16 day old fetuses. Raf-1 transcripts of 3.1 kb were found to be expressed in all tissues examined with highest levels in striated muscle, cerebellum and fetal brain. In contrast, A-raf showed wider variation in its range of expression, with the 2.6 kb transcripts being most abundant in epididymis and ovary. B-raf was found to have a very restricted expression pattern, with high levels in fetal brain and adult cerebrum. In addition to the 10 and 13 kb transcripts common to all B-raf expressing tissues, alternate sized B-raf RNAs were detected in testes, placenta and fetal membranes. We found no effect of gender on raf expression in non-sex related tissues, nor does tissue germline of origin correlate with levels of expression for any of the three genes.


Assuntos
Expressão Gênica , Proteínas Tirosina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Proto-Oncogenes , Animais , Northern Blotting , Feminino , Feto , Masculino , Camundongos , Camundongos Endogâmicos , Família Multigênica , Hibridização de Ácido Nucleico , Especificidade de Órgãos , Proteínas Proto-Oncogênicas c-raf , RNA/genética , RNA/isolamento & purificação
17.
Crit Rev Oncog ; 2(1): 1-8, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2091747

RESUMO

There are three active raf genes in man and at least two in Xenopus and Drosophila. The mammalian c- and A-raf genes have 16 coding exons, which span 40 and 20 kb, respectively. B-raf is larger and extends over greater than 46 kb. Human c-raf-1 maps to chromosome 3p25 and A-raf-1 to Xp21. c-raf-1 RNA is present in many tissues, while A-raf and B-raf expression is restricted. A- and c-raf encode cytoplasmic ser/thr protein kinases of 68 and 74 kDa, which contain three conserved regions (CR). CR1 and 2 are in the amino terminal half, CR1 comprises the presumed ligand binding site, and CR3 represents the carboxy terminal kinase domain. All three genes can be artificially activated by deletions, provided CR3 is preserved. However, only c-raf-1 occurs naturally in truncated versions, such as v-raf and v-mil in the acutely transforming retroviruses 3611-MSV and MH2. raf transformation can also be affected by point mutation, suggesting that this mechanism may activate c-raf-1 as an oncogene in carcinogenesis.


Assuntos
Neoplasias/genética , Proteínas Proto-Oncogênicas/genética , Proto-Oncogenes , Animais , Humanos , Neoplasias Experimentais/genética , Proteínas Tirosina Quinases/genética , Proteínas Proto-Oncogênicas c-raf
18.
J Immunol ; 140(10): 3528-33, 1988 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-3361124

RESUMO

A murine mAb, STEGI 1, was generated against a 30-kDa raf protein purified from an Escherichia coli expression vector. Immunoblot analysis confirmed that this antibody recognized the original immunizing protein as well as a 44- to 48-kDa protein from several raf-transformed cell lines. Immunoprecipitation experiments isolated a 48-kDa protein from a cell line transfected with a c-raf construct as well as from normal NIH 3T3 fibroblasts. Parallel experiments with polyvalent antiserum prepared against E. coli-derived v-raf (C terminus)-precipitated proteins with apparent Mr of 48 and 74 kDa, as had been described previously. Immunofluorescence flow cytometry of raf-transformed cell lines revealed intense intracytoplasmic staining. This staining was specifically inhibited by preincubation of STEGI 1 with purified raf 30-kDa protein. It should now be possible to more easily assess the role of the raf oncogene product in malignant transformation.


Assuntos
Anticorpos Monoclonais/análise , Proteínas dos Retroviridae/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/isolamento & purificação , Especificidade de Anticorpos , Eletroforese em Gel de Poliacrilamida , Citometria de Fluxo , Imunoensaio , Líquido Intracelular/análise , Camundongos , Camundongos Endogâmicos BALB C , Peso Molecular , Proteínas Oncogênicas v-raf , Testes de Precipitina , Proteínas dos Retroviridae/genética , Proteínas dos Retroviridae/isolamento & purificação
20.
Princess Takamatsu Symp ; 17: 55-74, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3332021

RESUMO

raf oncogenes were shown to act synergistically with myc in transformation. The contribution of myc was identified as that of a "second messenger" in signal transduction of at least some, competence inducing, growth factors. The role of raf appears to be that of a cytosolic ser/thr specific protein kinase which was placed downstream of ras in the signal transduction of serum growth factors by ras and raf antibody microinjection experiments. Because of the inability of raf to abrogate a cells need for myc inducing competence factors, as well as its synergistic effect with myc, raf was placed downstream of ras in the progression pathway of cellular growth control. We speculate that the basis for synergism with myc might be the ability of raf to activate competence factor induced myc protein or a myc induced protein by phosphorylation. The role of raf in lung tumors was examined by the development of a high incidence mouse model system using ethylnitrosourea as carcinogen and butylated hydroxytoluene as promoter. raf proteins of normal size were expressed at high levels, raf protein vaccination was apparently effective in eliminating the promoted phase of tumor induction.


Assuntos
Transformação Celular Neoplásica , Oncogenes , Sequência de Aminoácidos , Humanos , Dados de Sequência Molecular
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...