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1.
Radiología (Madr., Ed. impr.) ; 65(2): 99-105, mar.- abr. 2023. ilus, tab, graf
Artigo em Espanhol | IBECS | ID: ibc-217612

RESUMO

Objetivos Evaluar la seguridad y la eficacia de la embolización de arterias bronquiales y arterias sistémicas no bronquiales con n-butil-cianoacrilato en pacientes con hemoptisis. Métodos Se han analizado un total de 55 pacientes consecutivos con hemoptisis (14 leves, 31 moderadas y 10 masivas) tratados mediante embolización de arterias bronquiales y arterias sistémicas no bronquiales con n-butil- cianoacrilato entre noviembre de 2013 y enero de 2020. Las variables principales estudiadas son tasa de éxito técnico, tasa de éxito clínico, tasas de recurrencia y complicaciones. Se ha realizado un análisis estadístico descriptivo y un análisis de supervivencia mediante el método de Kaplan-Meier. Resultados En 55 (100%) pacientes se ha realizado la embolización con éxito técnico y en 54 (98,2%), con éxito clínico. Durante el seguimiento (media, 23,8 meses; rango intercuartílico, 9,7-38,2) ha recurrido en 5 de los 54 (9,3%) pacientes. La tasa de no recurrencia al año ha sido del 91,9%, y a los 2 y 4 años, del 88,7% después del procedimiento inicial. Ha habido 6 (10,9%) complicaciones menores relacionadas con el procedimiento y ninguna mayor. Conclusiones La embolización de arterias bronquiales y arterias sistémicas no bronquiales con n-butil-cianoacrilato es segura y eficaz para controlar la hemoptisis con tasas de recurrencia bajas (AU)


Objectives To evaluate the safety and efficacy of the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate (NBCA) in patients with hemoptysis. Methods We analyzed a total of 55 consecutive patients with hemoptysis (14 mild, 31 moderate, and 10 massive) treated with the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate between November 2013 and January 2020. The main variables analyzed were the rates of technical success, of clinical success, of recurrence, and of complications. Statistics included a descriptive analysis and Kaplan-Meier survival curves. Result Embolization was a technical success in 55 (100%) and a clinical success in 54 (98.2%). During follow-up (mean, 23.8 months; interquartile range, 9.7 – 38.2 months), hemoptysis recurred in 5 (9.3%) patients. The nonrecurrence rate was 91.9% one year after the initial procedure and 88.7% two years and four years after the initial procedure. Minor complications related with the procedure occurred in 6 (10.9%); no major complications occurred. Conclusions The embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate is safe and efficacious for controlling hemoptysis, resulting in low recurrence rates (AU)


Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Hemoptise/tratamento farmacológico , Embucrilato/uso terapêutico , Embolização Terapêutica/métodos , Artérias Brônquicas , Estudos Retrospectivos , Resultado do Tratamento , Índice de Gravidade de Doença , Estimativa de Kaplan-Meier , Recidiva
2.
Radiologia (Engl Ed) ; 65(2): 99-105, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37059585

RESUMO

OBJECTIVES: To evaluate the safety and efficacy of the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate (NBCA) in patients with hemoptysis. METHODS: We analyzed a total of 55 consecutive patients with hemoptysis (14 mild, 31 moderate, and 10 massive) treated with the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate between November 2013 and January 2020. The main variables analyzed were the rates of technical success, of clinical success, of recurrence, and of complications. Statistics included a descriptive analysis and Kaplan-Meier survival curves. RESULTS: Embolization was a technical success in 55 (100%) and a clinical success in 54 (98.2%). During follow-up (mean, 23.8 months; interquartile range, 9.7-38.2 months), hemoptysis recurred in 5 (9.3%) patients. The nonrecurrence rate was 91.9% one year after the initial procedure and 88.7% two years and four years after the initial procedure. Minor complications related with the procedure occurred in 6 (10.9%); no major complications occurred. CONCLUSIONS: The embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate is safe and efficacious for controlling hemoptysis, resulting in low recurrence rates.


Assuntos
Embolização Terapêutica , Embucrilato , Humanos , Artérias Brônquicas , Hemoptise/tratamento farmacológico , Hemoptise/etiologia , Embucrilato/uso terapêutico , Estudos Retrospectivos , Embolização Terapêutica/métodos
3.
Radiologia (Engl Ed) ; 2021 Feb 03.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-33549318

RESUMO

OBJECTIVES: To evaluate the safety and efficacy of the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate (NBCA) in patients with hemoptysis. METHODS: We analyzed a total of 55 consecutive patients with hemoptysis (14 mild, 31 moderate, and 10 massive) treated with the embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate between November 2013 and January 2020. The main variables analyzed were the rates of technical success, of clinical success, of recurrence, and of complications. Statistics included a descriptive analysis and Kaplan-Meier survival curves. RESULTS: Embolization was a technical success in 55 (100%) and a clinical success in 54 (98.2%). During follow-up (mean, 23.8 months; interquartile range, 9.7 - 38.2 months), hemoptysis recurred in 5 (9.3%) patients. The nonrecurrence rate was 91.9% one year after the initial procedure and 88.7% two years and four years after the initial procedure. Minor complications related with the procedure occurred in 6 (10.9%); no major complications occurred. CONCLUSIONS: The embolization of bronchial arteries and nonbronchial systemic arteries with n-butyl-cyanoacrylate is safe and efficacious for controlling hemoptysis, resulting in low recurrence rates.

4.
Radiologia (Engl Ed) ; 60(2): 128-135, 2018.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-29395109

RESUMO

OBJECTIVE: To evaluate the diagnostic performance of imaging-guided core needle biopsy of nodules and diffuse infiltration of the omentum or of the peritoneum. MATERIAL AND METHODS: We retrospectively evaluated 57 patients who underwent core needle biopsy of the peritoneum or of the omentum between March 2014 and January 2017. We used computed tomography (CT) to plan the biopsy. Biopsies were guided by CT or ultrasonography (US). We classified the results as diagnostic (benign / malignant) or inconclusive (inadequate sample). We calculated the sensitivity, specificity, positive-predictive value, and negative predictive value. We analyzed whether the specimen was diagnostic depending on the imaging technique used (CT or US) and on the type of omental or peritoneal involvement from which the specimen was obtained (mass, nodule, or diffuse involvement). RESULTS: All (100%) the percutaneous biopsies were diagnostic. The sensitivity of the technique was 98.18% and the specificity was 100%. The positive predictive value was 100% and the negative predictive value was 50%. Both the specimens obtained under CT guidance (n=10) and those obtained under US guidance (n=47) were diagnostic. Likewise, biopsies of masses (n=24), of nodules (n=17), and even of diffuse infiltration (n=16) of the peritoneum or omentum enabled the histologic diagnosis. The rate of complications was 1.75% (one death). CONCLUSION: Percutaneous core needle biopsy has high sensitivity regardless of the imaging technique used to guide the technique (CT or US) and of the type of lesion biopsied (mass, nodule, diffuse infiltration). It is a useful technique with a very low rate of complications, although severe complications can occur.


Assuntos
Mesentério/patologia , Doenças Peritoneais/patologia , Peritônio/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia com Agulha de Grande Calibre , Feminino , Humanos , Biópsia Guiada por Imagem , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
5.
Radiología (Madr., Ed. impr.) ; 55(4): 323-330, jul.-ago. 2013.
Artigo em Espanhol | IBECS | ID: ibc-113665

RESUMO

Objetivo. Definir los hallazgos radiológicos en tomografía computarizada (TC) de los tumores carcinoides bronquiales y determinar si estos hallazgos permiten clasificarlos en típicos o atípicos. Material y métodos. Se revisaron retrospectivamente los TC de tórax de pacientes con diagnóstico histológico de tumor carcinoide bronquial realizados en nuestro hospital entre el 1 de enero de 2001 y el 31 de diciembre de 2009. La muestra estaba formada por 52 pacientes (23 mujeres y 29 varones) con una edad media de 47 años (rango de edad11-77 años). Se catalogaron los 52 casos como típicos o atípicos en función del tamaño, localización, focalidad, tipo de crecimiento, calcificaciones, signos secundarios a obstrucción bronquial y presencia de adenopatías de tamaño significativo o de metástasis. Posteriormente se compararon los resultados con la anatomía patológica. Resultados. Los tumores carcinoides típicos fueron los más prevalentes (46 casos). Las variables asociadas a los atípicos fueron el sexo masculino, edad tardía de presentación y tamaño> 3 cm. Cuantas más variables atípicas reúnen los tumores carcinoides, mayor es la sensibilidad de la TC para diagnosticarlos correctamente. La ausencia de variables atípicas permite excluir el diagnóstico de tumor carcinoide atípico hasta en un 95% de los casos. Conclusión. La TC es una técnica que ayuda a definir y caracterizar radiológicamente los tumores carcinoides como típicos o atípicos, aunque por ahora no existe una fórmula precisa para diferenciarlos (AU)


Objective. To define the CT findings for bronchial carcinoid tumors and to determine whether these findings enable these tumors to be classified as typical or atypical. Material and methods. We reviewed the chest CT studies performed between 1 January 2001 and 31 December 2009 in patients at our hospital diagnosed with bronchial carcinoid tumors. The sample consisted of 52 patients (23 women and 29 men) with a mean age of 47 years (range 11-77 years). The 52 cases were classified as typical or atypical on the basis of the following radiological findings: size, location, focality, type of growth, calcifications, signs secondary to bronchial obstruction, and the presence of significant lymph node enlargement or metastases. These findings were then compared with the histological findings. Results. Typical carcinoid tumors were the most prevalent (46 cases). The variables associated with atypical tumors were: male sex, advanced age at onset, and size > 3 cm. The accuracy of CT in classifying atypical tumors correctly increased with the number of variables indicative of atypical carcinoid tumors. A negative result for atypical nature made it possible to rule out an atypical carcinoid tumor in 95% of the cases. Conclusion. CT is useful for defining and characterizing carcinoid tumors into typical or atypical, although a precise formula for differentiating between the two types remains to be defined (AU)


Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Tumor Carcinoide , /instrumentação , /métodos , Tumores Neuroendócrinos , Neoplasias Brônquicas/complicações , Neoplasias Brônquicas , Estudos Retrospectivos , Tórax , Tomografia Computadorizada Multidetectores/instrumentação , Tomografia Computadorizada Multidetectores/métodos , Tomografia Computadorizada Multidetectores , Broncoscopia/métodos , Broncoscopia/tendências , Intervalos de Confiança
6.
Radiologia ; 55(4): 323-30, 2013.
Artigo em Espanhol | MEDLINE | ID: mdl-22305010

RESUMO

OBJECTIVE: To define the CT findings for bronchial carcinoid tumors and to determine whether these findings enable these tumors to be classified as typical or atypical. MATERIAL AND METHODS: We reviewed the chest CT studies performed between 1 January 2001 and 31 December 2009 in patients at our hospital diagnosed with bronchial carcinoid tumors. The sample consisted of 52 patients (23 women and 29 men) with a mean age of 47 years (range 11-77 years). The 52 cases were classified as typical or atypical on the basis of the following radiological findings: size, location, focality, type of growth, calcifications, signs secondary to bronchial obstruction, and the presence of significant lymph node enlargement or metastases. These findings were then compared with the histological findings. RESULTS: Typical carcinoid tumors were the most prevalent (46 cases). The variables associated with atypical tumors were: male sex, advanced age at onset, and size >3cm. The accuracy of CT in classifying atypical tumors correctly increased with the number of variables indicative of atypical carcinoid tumors. A negative result for atypical nature made it possible to rule out an atypical carcinoid tumor in 95% of the cases. CONCLUSION: CT is useful for defining and characterizing carcinoid tumors into typical or atypical, although a precise formula for differentiating between the two types remains to be defined.


Assuntos
Neoplasias Brônquicas/diagnóstico por imagem , Neoplasias Brônquicas/patologia , Tumor Carcinoide/diagnóstico por imagem , Tumor Carcinoide/patologia , Tomografia Computadorizada Multidetectores , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
7.
Rev Neurol ; 40(3): 163-5, 2005.
Artigo em Espanhol | MEDLINE | ID: mdl-15750902

RESUMO

INTRODUCTION: Transient ischemic attacks (TIA) occur as the clinical manifestation of a pulmonary arteriovenous malformation in up to 20% of cases. CASE REPORT: We report the case of a 41-year-old female with an episode of TIA lasting half an hour, with right-side hemiparesis caused by a paradoxical embolisation due to the presence of a single pulmonary arteriovenous fistula (PAVF). Complementary analytical and imaging tests (CAT scan of the head without contrast, brain RMI and intra and extracranial MR-angiography) were normal. A transthoracic echocardiogram showed the presence of a patent foramen ovale which obstructed the passage of hemoce, although it was observed in the left auricle after presumably arriving through the pulmonary arteries. Since a pulmonary vascular malformation was suspected, a computerised tomographic angiography scan of the thorax was performed and this confirmed the presence of a single PAVF in the right lung. A pulmonary arteriography was then carried out to confirm the presence of the malformation, which was later embolised. Two months later, the patient was asymptomatic and the fistula did not appear in the computerised tomographic angiography scan of the thorax. CONCLUSIONS: PAVFs can give rise to neurological conditions due to paradoxical embolisms that can produce abscesses and infarcts and/or concomitant lesions in the central nervous system. This is a certain indication of treatment of the malformation and the preferred technique is endovascular embolisation with coils, while surgery is reserved for cases in which endovascular treatment is not possible.


Assuntos
Fístula Arteriovenosa/complicações , Fístula Arteriovenosa/diagnóstico , Ataque Isquêmico Transitório/diagnóstico , Ataque Isquêmico Transitório/etiologia , Artéria Pulmonar/anormalidades , Adulto , Angiografia , Fístula Arteriovenosa/patologia , Ecocardiografia , Feminino , Humanos , Ataque Isquêmico Transitório/patologia , Tomografia Computadorizada por Raios X
8.
Gac Sanit ; 15(3): 245-50, 2001.
Artigo em Espanhol | MEDLINE | ID: mdl-11423029

RESUMO

OBJECTIVES: To determine the opinions of hospital and other research organizations managers concerning three questions: 1) the desirability of healthcare centers' managing biomedical research as a specific product; 2) the characteristics that define a "research management" culture as opposed to the current "administration of research" culture and 3) the management instruments needed to implement a "research management" culture. MATERIALS AND METHODS: A meeting was held with 14 experts from healthcare centers or research organizations from Barcelona, Madrid and Valencia to discuss the three questions and evaluate the relative importance of items comprising the last two with a score system from 1 (little relevance) to 9 (extremely relevant). RESULTS: The group was in favor of healthcare centers' managing research as a specific and differentiated product. Keys to achieving a management culture (items scoring higher than 7 with the above system) included the development of a culture to evaluate work and external auditing, transversal support and sharing infrastructures and intellectual capital, specific accounting, unified management, prioritization of research lines and capacity for cooperation, and strategic alliances between centers. Management instruments deemed essential (items scoring 7 or higher with the above system) were: support to research foundations or other organizational formulae to ensure autonomy, specific budgetary control, development of support structures and contractual formulae to support autonomy, creativity and researchers' accountability. CONCLUSIONS: Research conducted in healthcare centers should be managed just as any other product derived from the center's activities. Key points to success are prioritization, evaluation and clear assignation of responsibilities, which requires organizational structures with greater flexibility and specific information systems.


Assuntos
Atitude do Pessoal de Saúde , Administradores Hospitalares/psicologia , Pesquisa/organização & administração , Humanos , Cultura Organizacional , Pesquisa/estatística & dados numéricos , Apoio à Pesquisa como Assunto/estatística & dados numéricos , Espanha , Inquéritos e Questionários
9.
Gac. sanit. (Barc., Ed. impr.) ; 15(3): 245-250, mayo-jun. 2001.
Artigo em Es | IBECS | ID: ibc-1643

RESUMO

Objetivo: Conocer las opiniones de directivos de hospitales y organizaciones de investigación con relación a: a) si es deseable que los centros sanitarios gestionen la investigación biomédica de manera específica y diferenciada; b) las características que definen la gestión de la investigación, y c) determinar qué instrumentos son necesarios para poder introducir criterios de gestión en investigación. Material y métodos: Grupo nominal con 14 responsables de centros hospitalarios u organizaciones de investigación de Barcelona, Madrid y Valencia, que respondieron y discutieron los tres aspectos planteados en los objetivos y valoraron la importancia relativa de los dos últimos mediante una puntuación de 9 (muy relevante) a uno (poco relevante). Resultados: El grupo se mostró partidario de gestionar la investigación en los centros sanitarios como un producto específico y diferenciado. Las respuestas que alcanzaron más de 7 puntos en la segunda pregunta incluyen: el desarrollo de una cultura de evaluación y auditoría externa, el soporte transversal y uso común de las infraestructuras y el capital intelectual, la contabilidad específica, la dirección unitaria, la priorización de líneas de investigación y la capacidad para cooperar y establecer alianzas estratégicas entre centros. Las respuestas que alcanzaron 7 o más puntos en la tercera pregunta incluyen: el apoyo a las fundaciones de investigación u otras fórmulas organizativas para impulsar la autonomía de la gestión de la investigación, la gestión presupuestaria específica, el desarrollo de estructuras de apoyo y el desarrollo de fórmulas contractuales de soporte a la autonomía, creatividad y responsabilidad de los investigadores. Conclusiones: El grupo mostró un amplio consenso en que la investigación en los centros sanitarios debería ser gestionada al igual que se hace con otras áreas de la actividad sanitaria; esta gestión se caracterizaría por la priorización, la evaluación y la responsabilidad, y requiere fórmulas organizativas con mayor flexibilidad y sistemas de información específicos (AU)


Assuntos
Humanos , Atitude do Pessoal de Saúde , Espanha , Cultura Organizacional , Pesquisa , Apoio à Pesquisa como Assunto , Inquéritos e Questionários , Administradores Hospitalares
11.
Gac Sanit ; 14(5): 391-7, 2000.
Artigo em Espanhol | MEDLINE | ID: mdl-11187458

RESUMO

At the end of the present century a significant coincidence underpins the growing interest for the social legitimation of the public health systems by means of a scientific knowledge base as well as an unprecedented transformation of some research organizative features--multidisciplinarity, resource concentration and common utilisation of the support infrastructures--the paradigms and the technological domain related to genomics and molecular engineering. Under such circumstances there has been a renewed interest about strategic thinking from the perspective of biomedical science and technology. The central question addressed by this report aims to review some issues related with the economic analysis of biomedical research as a collectively provided public good and to discuss the impact of the new economics of information on creating research strategies.


Assuntos
Financiamento Governamental/economia , Apoio à Pesquisa como Assunto/economia , Alocação de Recursos para a Atenção à Saúde , Serviços de Informação
12.
Mol Cell Biol ; 16(9): 4700-9, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8756627

RESUMO

alpha-Factor, a 13-amino-acid pheromone secreted by haploid alpha cells of Saccharomyces cerevisiae, binds to Ste2p, a seven-transmembrane, G-protein-coupled receptor present on haploid alpha cells, to activate a signal transduction pathway required for conjugation and mating. To determine the structural requirements for alpha-factor activity, we developed a genetic screen to identify from random and semirandom libraries novel peptides that function as agonists or antagonists of Ste2p. The selection scheme was based on autocrine strains constructed to secrete random peptides and respond by growth to those that were either agonists or antagonists of Ste2p. Analysis of a number of peptides obtained by this selection procedure indicates that Trp1, Trp3, Pro8, and Gly9 are important for agonist activity specifically. His2, Leu4, Leu6, Pro10, a hydrophobic residue 12, and an aromatic residue 13 are important for both agonist and antagonist activity. Our results also show that activation of Ste2p can be achieved with novel, unanticipated combinations of amino acids. Finally, the results suggest the utility of this selection scheme for identifying novel ligands for mammalian G-protein-coupled receptors heterologously expressed in S. cerevisiae.


Assuntos
Peptídeos/farmacologia , Peptídeos/fisiologia , Receptores de Peptídeos/fisiologia , Saccharomyces cerevisiae/fisiologia , Transdução de Sinais/efeitos dos fármacos , Fatores de Transcrição , Sequência de Aminoácidos , Aminoácidos/química , Sequência de Bases , Fator de Acasalamento , Técnicas Microbiológicas , Dados de Sequência Molecular , Peptídeos/química , Estrutura Terciária de Proteína , Receptores de Fator de Acasalamento , Receptores de Peptídeos/agonistas , Receptores de Peptídeos/antagonistas & inibidores , Saccharomyces cerevisiae/efeitos dos fármacos , Seleção Genética , Relação Estrutura-Atividade
13.
Immunology ; 69(1): 104-9, 1990 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2312149

RESUMO

The inhibitory effect of cyclosporin (CsA) was investigated on human lymphocytes stimulated by anti-T-cell antibodies (anti-CD3 and -CD2) or mitogenic lectins. Whereas inhibition of cell proliferation (50%) occurred at 10 ng/ml CsA after cell activation via CD3 or CD2, higher CsA concentrations (300 ng/ml) were necessary to inhibit lectin-mediated cell activation (PHA, Con A). Exogenous recombinant interleukin-2 (rIL-2) partially reversed the inhibitory effect on antibody-stimulated cells only; however, at higher CsA concentrations (300 ng/ml) proliferation was again inhibited. Thus, CsA affected IL-2R expression and/or function at higher concentrations (300 ng/ml). CsA had no effect on receptor function as measured on IL-2-dependent cell growth of CTLL cells or preactivated lymphocytes. However, CsA inhibited both high and low affinity receptor expression as shown by [125I]IL-2 equilibrium binding studies on anti-CD3-stimulated cells. Cross-linking studies revealed that both p55 (TAC) and p75 chains of the IL-2R were not induced at low CsA concentrations (10 ng/ml). However, addition of rIL-2 reversed CsA inhibition of IL-2R expression. It is concluded that CsA, at least in anti-CD3-stimulated cells, inhibits IL-2R expression and cell proliferation with similar potency. Exogenous rIL-2 reverses CsA inhibition of IL-2R expression. This might be due to binding of rIL-2 to receptors which escape CsA inhibition, thereby up-regulating receptor expression which is drug resistant.


Assuntos
Antígenos CD/imunologia , Ciclosporinas/farmacologia , Receptores de Interleucina-2/efeitos dos fármacos , Linfócitos T/imunologia , Anticorpos Monoclonais/imunologia , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Ciclosporinas/antagonistas & inibidores , Humanos , Interleucina-2/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Linfócitos T/citologia
15.
Mol Cell Biol ; 8(5): 2042-51, 1988 May.
Artigo em Inglês | MEDLINE | ID: mdl-3386632

RESUMO

The report that human growth hormone pre-mRNA is not processed in transgenic plant tissues (A. Barta, K. Sommergruber, D. Thompson, K. Hartmuth, M.A. Matzke, and A.J.M. Matzke, Plant Mol. Biol. 6:347-357, 1986) has suggested that differences in mRNA splicing processes exist between plants and animals. To gain more information about the specificity of plant pre-mRNA processing, we have compared the splicing of the soybean leghemoglobin pre-mRNA with that of the human beta-globin pre-mRNA in transfected plant (Orychophragmus violaceus and Nicotiana tabacum) protoplasts and mammalian (HeLa) cells. Of the three introns of leghemoglobin pre-mRNA, only intron 2 was correctly and efficiently processed in HeLa cells. The 5' splice sites of the remaining two introns were faithfully recognized, but correct processing of the 3' sites took place only rarely (intron 1) or not at all (intron 3); cryptic 3' splice sites were used instead. While the first intron in human beta-globin pre-mRNA was not spliced in transfected plant protoplasts, intron 2 processing occurred at a low level, indicating that some mammalian introns can be recognized by the plant intron-splicing machinery. However, excision of intron 2 proved to be incorrect, involving the authentic 5' splice site and a cryptic 3' splice site. Our results indicate that the mechanism of 3'-splice-site selection during intron excision differs between plants and animals. This conclusion is supported by analysis of the 3'-splice-site consensus sequences in animal and plant introns which revealed that polypyrimidine tracts, characteristic of animal introns, are not present in plant pre-mRNAs. It is proposed that an elevated AU content of plant introns is important for their processing.


Assuntos
Plantas/metabolismo , Precursores de RNA/metabolismo , Splicing de RNA , Sequência de Bases , Células HeLa/metabolismo , Humanos , Leghemoglobina/genética , Dados de Sequência Molecular , Plantas/genética , Protoplastos/metabolismo , Especificidade da Espécie
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