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1.
Rev. MVZ Córdoba ; 23(2): 6681-6695, May-Aug. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-957363

RESUMO

Abstract Objectives. The aim of this study is to evaluate the relationship among ovulatory follicle (OF) size, corpus luteum (CL) volume, and progesterone (P4) serum levels with pregnancy success. Materials and methods. Nineteen Holstein cows located in Bogotá, Colombia with a history of 2 to 6 previous calving were used in the study. Following 40 day postpartum, two consecutive phases were evaluated as follows: 1) estrous cycle; 2) early pregnancy or return to estrus after Artificial Insemination (AI). Ultrasound exam was performed twice daily after first sign of estrus to evaluate OF diameter and CL volume, and serum P4 levels were evaluated on days 6, 9, 12 and 15 after ovulation. Cows were inseminated 12 hours post estrus signs and pregnancy was diagnosed 30 days post AI. Results. 47.36% of the cows were diagnosed as pregnant after AI. Pregnant cows had smaller OF diameters (17.85±2.39 mm) than non-pregnant females (21.10±2.86 mm) (p<0.05). Cows with smaller OF were more likely to become pregnant (OR=0.624, IC=95% (0.4-0.9) (p<0.05). There were non significant differences in the CL volume (p=0.10) and P4 serum values (p=0.39) between pregnant and no pregnant cows on days 6, 9, 12 and 15 post ovulation. Serum P4 levels were not correlated to CL size and reproductive status. Conclusions. This study shows that there was not significant difference in serum P4 levels and the CL volume when comparing pregnant with non-pregnant cows. A relationship was found between the OF diameter and the CL volume. Small OF diameter was a factor associated with early pregnancy.


Resumen Objetivo. Evaluar la relación entre el diámetro del folículo ovulatorio (FO), el volumen del cuerpo lúteo (CL), los niveles séricos de progesterona (P4) con el éxito de la gestación. Materiales y métodos. En 19 vacas Holstein que habían tenido 2 a 6 partos ubicadas en Bogotá, se evaluaron dos fases consecutivas a partir del día 40 postparto, la primera correspondió al ciclo estral y la segunda correspondió a la gestación temprana o repetición de celo. En cada fase se detectó el celo, se realizó ultrasonografía para evaluar el diámetro del FO, confirmar ovulación, y el volumen del CL los días 6, 9, 12 y 15; en estos días también se evaluó los niveles séricos de P4. En la segunda fase se realizó inseminación artificial (IA) y se diagnosticó la gestación 30 días post-IA. Resultados. El 47.36% de las vacas se diagnosticaron como gestantes y el 52.63% como no gestantes. Las gestantes presentaron diámetros de FO menores 17.85±2.39 mm al de las no gestantes (21.10±2.86 mm; p<0.05). Las vacas que presentaron diámetros de FO más pequeños tuvieron mayor posibilidad de quedar gestantes (OR=0.624, IC=95% (0.4-0.9) (p<0.05). Los animales gestantes y no gestantes presentaron similares volúmenes de CL (p=0.10) y niveles séricos de P4 (p=0.39) los días 6, 9, 12 y 15. Conclusiones. No hubo diferencias en los niveles séricos de p4 y el volúmen del CL. Vacas con FO de menor diámetro tuvieron mayor probabilidad de gestación. Otras variables como CL y niveles de P4 no fueron predictivos del éxito de la gestación.


Assuntos
Animais , Ovário , Progesterona , Gravidez , Bovinos , Ciclo Estral , Período Pós-Parto
2.
Rev. MVZ Córdoba ; 22(2): 5951-5958, May-Aug. 2017. graf
Artigo em Inglês | LILACS | ID: biblio-896937

RESUMO

ABSTRACT Objective. To determine the effect of hypobaric hypoxia exposition in pulmonary arterioles expression of endothelin-1 (ET-1). Materials and methods. Two groups of commercial broiler chickens were used: one of them were raised at 2638 (hypobaric hypoxia) and the other one at 300 m (relative normoxia) above sea level. Incidence of pulmonary hypertension (PH) was evaluated by calculating the cardiac mass index values and ET-1 protein expression was established in pulmonary arterioles by immunohistochemistry and morphometry. Results . ET-1 expression was higher in arterioles of animals exposed to hypoxia as compared to the low altitude exposed broilers (p<0.01). Arterioles from pulmonary hypertensive chickens (PHC) showed ET-1 higher expression than arterioles from healthy chickens (non-hypertensive, NHC) at low altitude, those exposed to hypobaric hypoxia (p<0.01). 53% of chickens subjected to altitude conditions developed pulmonary hypertension. Under normoxia, no chickens developed that pathology. Conclusions. Quantitative characteristics and sites of ET-1 expression in the lungs are important in the understanding of PH pathogenesis in broilers and the adapting mechanisms to hypobaric hypoxia, as to design new pharmacological approaches. This is a first approach which accounts for the abovementioned features in broilers subjected to natural conditions of normoxia and hypobaric hypoxia.


RESUMEN Objetivo. Determinar el efecto de la exposición a hipoxia hipobárica sobre la expresión de Endotelina-1 en arteriolash pulmonares. Material y métodos. Se utilizaron 2 grupos de pollos de engorde de una estirpe comercial: uno de ellos criados a 2638 y el otro, a 300 m de altitud. La incidencia de HAP se evaluó según los valores del índice de masa cardiaca y se compararon los niveles de expresión de la proteína ET-1 en arteriolas pulmonares de pollos de engorde sanos y enfermos por HAP mediante inmunohistoquímica y morfometría. Resultados. La expresión de la proteína ET-1 fue mayor en las arteriolas de los pollos expuestos a hipoxia hipobárica que en los criados bajo condiciones de normoxia relativa (p<0.01). Los animales enfermos por HAP presentaron mayor expresión de la proteína ET-1 en las arteriolas pulmonares que los animales sanos ubicados en las dos altitudes (p<0.01). 53% de los animales desarrollaron hipertensión pulmonar y ninguno de los mantenidos en normoxia lo hicieron. Conclusiones. El conocimiento de las características cuantitativas y lo sitios de expresión de la ET-1 son elementos importantes para entender aún más la patogenia de la HAP y el diseño de fármacos para su control. Este estudio constituye la primera aproximación cuantitativa relacionada con la expresión de ET-1 en pollos de engorde con HAP de origen hipóxico no inducida.

3.
Transplant Proc ; 37(8): 3358-60, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16298595

RESUMO

INTRODUCTION: One-year serum creatinine (SCr) level has been used as a surrogate marker for graft survival in kidney transplantation. We evaluated the importance of different factors on this parameter, emphasizing the importance of adequate exposure to Cyclosporine (CyA). METHODS: Ninety-six consecutive renal transplant recipients who underwent transplantation between 1996 and 2002 were treated with CyA, steroids, and azathioprine. Univariate and multivariate regression analyses were performed for 1-year SCr, acute rejection episodes (ARE), and duration of delayed graft function (DGF). We considered adequate CyA levels within 1 week to be >250 ng/mL trough levels (38%) or 3 hour postdose level (C3) >1100 ng/mL (62%). RESULTS: Mean 1-year SCr was 1.52 +/- 0.5, ARE rate was 27%, and DGF rate was 31%. Overall, 53% of patients achieved adequate exposure to CyA at 1 week (68% on those monitored by C3). Univariate analysis identified female recipient gender, decreasing donor age, absence of ARE, and decreased DGF duration to yield lower 1-year SCr (P < .05). On multivariate analysis for donor age (lower), ARE rate, and duration of DGF (shorter) were the only factors considered to be significant for a lower 1-year SCr level. Multivariate analysis for ARE showed that adequate CyA exposure and lower HLA mismatch decreased ARE, whereas the ability to achieve adequate exposure to CyA and shorter cold ischemia time (CIT) correlated with a reduced incidence of DGF. CONCLUSIONS: One-year SCr level is affected primarily by the incidence of ARE, by donor age, and by duration of DGF. Adequate CyA exposure is related to lower ARE; however, its relation to DGF may be influenced by the reluctance to increase exposure on patients with a nonfunctioning graft.


Assuntos
Ciclosporina/uso terapêutico , Transplante de Rim/fisiologia , Creatinina/sangue , Ciclosporina/administração & dosagem , Esquema de Medicação , Feminino , Rejeição de Enxerto/epidemiologia , Humanos , Imunossupressores/administração & dosagem , Imunossupressores/uso terapêutico , Transplante de Rim/imunologia , Masculino , Análise Multivariada , Resultado do Tratamento
4.
Transplant Proc ; 37(8): 3361-3, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16298596

RESUMO

INTRODUCTION: Delayed graft function has been associated with worse long-term kidney allograft survival. Adequate diagnosis of the etiology of dysfunction is crucial, often requiring routine early biopsies. The aim of this article was to report the results and safety of early kidney allograft biopsies and how they influenced its management. METHOD: Between September 1994 and July 2004, 134 renal transplant recipients were prescribed cyclosporine (CsA; Neoral, Novartis, Chile), steroids, and a third agent (azathioprine in 92% of the graft recipients). Thirty-four patients (26%) had a kidney biopsy performed within the first week because of allograft dysfunction. RESULTS: The main diagnosis was acute tubular necrosis (ATN) in 22 patients (65%), whereas 6 (18%) were diagnosed with an acute rejection episode (ARE), allowing prompt initiation of therapy with reversal of rejection in 4 of them. Two patients (6%) showed signs of thrombotic microangiopathy (TMA) induced by CsA, which subsided following a switch from CsA to tacrolimus (Prograf Pharmainvesti, Chile). In 2 patients, the biopsy specimen showed signs of CsA nephrotoxicity that reverted following dose reduction. Finally, in 2 patients, the biopsy specimen showed chronic nephropathy of donor origin, which had not been previously recognized, resulting in graft loss. There was only one major complication related to the biopsy, intraperitoneal bleeding that required surgical treatment. CONCLUSIONS: Early allograft biopsy is safe and, in a significant number of cases (30%), it detects important allograft pathology (ARE, TMA, and drug toxicity), which when adequately and promptly treated may rescue the graft.


Assuntos
Transplante de Rim/patologia , Doença Aguda , Adulto , Biópsia , Feminino , Humanos , Transplante de Rim/fisiologia , Túbulos Renais/patologia , Masculino , Microcirculação/patologia , Necrose , Circulação Renal , Estudos Retrospectivos , Resultado do Tratamento
5.
Transplant Proc ; 37(3): 1583-5, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15866680

RESUMO

INTRODUCTION: C2 (2-hour post-absorption levels) monitoring of cyclosporine (CsA) seems to reduce the rate of acute rejection episodes (ARE) without increasing nephrotoxicity during the first months after transplant. There are a few reports on the impact of adopting this strategy in patients with stable renal transplants. We herein report a prospective trial in long-term renal transplant patients (>6 months) monitored by C0 or C3 who were switched to C2 monitoring. METHODS: Seventy-six (mean age = 43 +/- 11 years) kidney transplant patients (mean = 37 +/- 21 months after transplant) receiving CsA, steroids, and azathioprine were switched to C2 monitoring, seeking to achieve a target range of 800 +/- 100 ng/mL. The patients were followed for at least 6 months. RESULTS: At conversion the C2 values of 61% of the patients were above and 17% below the therapeutic range. Six months after conversion there was a significant reduction in BUN (29 +/- 11 vs 27 +/- 10, P < .01), Creatinine (Cr), cholesterol, and triglyceride levels were unchanged. Mean CsA dose was decreased 10% from 244 +/- 63 to 220 +/- 52 (P < .01), implying a net savings of 390 US dollars per patient per year. Among the group of patients who showed a high C2 level, there was also a reduction in BUN (30 +/- 12 vs 27 +/- 10, P < .01) and a nonsignificant decrease in Cr (1.53 +/- 0.6 vs 1.50 +/- 0.6). CONCLUSIONS: C2 monitoring in stable kidney transplant recipients is feasible and safe. The strategy results in reduced drug costs and improved renal function.


Assuntos
Ciclosporina/uso terapêutico , Imunossupressores/uso terapêutico , Transplante de Rim/fisiologia , Adulto , Nitrogênio da Ureia Sanguínea , Chile , Custos e Análise de Custo , Creatinina/sangue , Ciclosporina/economia , Ciclosporina/farmacocinética , Monitoramento de Medicamentos/métodos , Feminino , Hematócrito , Humanos , Imunossupressores/economia , Imunossupressores/farmacocinética , Testes de Função Renal , Transplante de Rim/imunologia , Metabolismo dos Lipídeos , Masculino , Taxa de Depuração Metabólica , Fatores de Tempo
6.
Sci Total Environ ; 276(1-3): 83-92, 2001 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-11516141

RESUMO

Ambient air measurements collected from 1994 to 1995 were used in a preliminary assessment of potential source and spatial influences in the Ambos Nogales border region (Nogales, Arizona, USA and Nogales, Sonora, Mexico). In this assessment, volatile organic compounds (VOC) and particulate matter (PM) species were used from four sites, two on either side of the border. An examination of median levels and principal component analysis indicated the dominance of soil dusts and mobile sources. Pairwise comparisons of sites for VOCs associated with mobile sources revealed statistically significant differences between sites in the central Nogales area vs. the two sites furthest from the border. Particulate lead at Mexican sites was higher and significantly different vs. US sites. Although further analyses are necessary, findings suggest that local and immediate mobile/other anthropogenic and soil dust influences are present throughout Nogales, with particulate lead from leaded motor vehicle exhaust or soldering operations being a possible influence on the Mexican side.


Assuntos
Poluição do Ar/análise , Monitoramento Ambiental , Movimentos do Ar , Poeira , México , Compostos Orgânicos/análise , Tamanho da Partícula , Poluentes do Solo/análise , Estados Unidos , Volatilização
7.
Artigo em Espanhol | LILACS | ID: lil-213257

RESUMO

La fractura de Monteggia es muy rara y comprende solo el 2 por ciento de las fracturas que afectan el codo en niños, con una incidencia por edades que va desde 7 a 10 años, pero puede aparecer en lactantes y adolescentes. Su rareza ha despertado enorme interés por las complicaciones graves que conlleva su tratamiento inadecuado, o cuando en el peor de los casos no se le diagnostica. Presentamos un escolar femenino de 10 años de edad quien posterior a caida desde sus propios pies con el codo en hiperextensión presentó deformidad e impotencia funcional del codo izquierdo. En estudios radiológicos diagnostica luxo-fractura de Monteggia tipo I, realizando cerrada y colocación de yeso braquipalmar en supinación evolucionando satisfactoriamente


Assuntos
Humanos , Feminino , Luxações Articulares , Fratura de Monteggia/cirurgia , Ferimentos e Lesões/complicações
8.
Bol. Hosp. Niños J. M. de los Ríos ; 33(2): 49-53, mayo-ago. 1997. tab
Artigo em Espanhol | LILACS | ID: lil-203386

RESUMO

Se trata de una revisión retrospectiva de los traumatismos en menores de 18 años que ingresaron a la emergencia del Hospital de Emergencia del El Valle "Dr. Leopoldo Manrique Terrero". Con el diagnóstico de traumatismo abdominal puro, en el período comprendido entre enero de 1992 y diciembre de 1996. Durante ese lapso ingresaron 140 pacientes de los cuales 134 (95,72 por ciento) fueron de sexo masculino. El rango de edad más frecuente varió entre los 13 y 18 años con un 87,56 por ciento. El agente causal más frecuente fue herida por arma de fuego con un 74,28 por ciento. De los 140 pacientes a 126(90 por ciento) se le realizó laparotomía, de los cuales se complicaron 33 pacientes (26 por ciento) y tuvimos 10 defunciones que representaron el 7.1 por ciento


Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Adolescente , Traumatismos Abdominais/diagnóstico , Traumatismos Abdominais/etiologia , Criança
12.
Exp Parasitol ; 66(1): 7-12, 1988 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3366216

RESUMO

Nine hybridoma cell lines secreting monoclonal antibodies specific for Nematospiroides dubius were produced by fusion of the mouse myeloma cell line NS-1 to either spleen cells or mesenteric lymph node cells from mice repeatedly infected with N. dubius. Seven of the antibodies were identified as IgM and two as IgG1. Each monoclonal antibody bound to polypeptide epitopes on both infective larvae (L3) and adult worms. However, five antibodies bound preferentially to L3 and three to adult worms. All nine antibodies reacted with high molecular weight protein antigens. Passive protective immunity in Balb/c mice was demonstrated with monoclonal antibodies Nd2 and Nd3 in ascites fluid which stunted both male and female worms and reduced parasite fecundity.


Assuntos
Anticorpos Monoclonais/imunologia , Heligmosomatoidea/imunologia , Imunização Passiva , Infecções por Nematoides/imunologia , Nematospiroides dubius/imunologia , Animais , Anticorpos Anti-Helmínticos/imunologia , Ensaio de Imunoadsorção Enzimática , Fezes/parasitologia , Feminino , Hibridomas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Nematoides/parasitologia , Nematospiroides dubius/crescimento & desenvolvimento , Contagem de Ovos de Parasitas
13.
Aust J Exp Biol Med Sci ; 63 ( Pt 4): 423-30, 1985 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-4084141

RESUMO

Various preparations of somatic Nematospiroides dubius antigens were emulsified in Freund's complete adjuvant and assayed in Quackenbush mice for efficacy as vaccines against homologous infection. Soluble and particulate fractions were given by two different routes. Only minimal protection was induced by vaccination with either soluble or particulate parasite fractions used independently when compared with the adjuvant control. Fewer and smaller worms were recovered from, and significantly fewer parasite eggs were voided by, mice which had been treated previously with both soluble somatic protein (15 micrograms N. dubius per mouse) by the intraperitoneal route and particulate antigen by subcutaneous injection. These mice showed higher antibody titres in comparison with other mice treated with either fraction alone. Further, treatment with both antigen fractions together appeared to exert a synergistic effect in comparison with either fraction administered alone.


Assuntos
Heligmosomatoidea/imunologia , Infecções por Nematoides/prevenção & controle , Nematospiroides dubius/imunologia , Vacinas/isolamento & purificação , Animais , Formação de Anticorpos , Antígenos/administração & dosagem , Antígenos/isolamento & purificação , Feminino , Camundongos , Infecções por Nematoides/imunologia , Infecções por Nematoides/parasitologia , Contagem de Ovos de Parasitas , Solubilidade , Vacinação , Vacinas/administração & dosagem
14.
J Clin Invest ; 73(1): 116-23, 1984 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-6690472

RESUMO

The concurrence of sickle cell anemia and alpha-thalassemia results in less severe hemolytic anemia apparently as a result of reduced intraerythrocytic concentration of hemoglobin S and its retarded polymerization. We have evaluated the effect of alpha-globin gene number on several interrelated properties of sickle erythrocytes (RBC) that are expected to correlate with the hemolytic and rheologic consequences of sickle cell disease. The irreversibly sickled cell number, proportion of very dense sickle RBC, and diminished deformability of sickle RBC each varied directly with alpha-globin gene number. Sickle RBC density was a direct function of the mean corpuscular hemoglobin concentration (MCHC). Even in nonsickle RBC, alpha-globin gene number varied directly with RBC density. Despite differences in alpha-globin gene number, sickle RBC of the same density had the same degree of deformability and dehydration. These data indicate that the fundamental effect of alpha-thalassemia is to inhibit the generation of sickle RBC having high density and MCHC, and that the other beneficial effects of sickle RBC are secondary to this process. The less consistent effect on overall clinical severity reported for subjects with this concurrence may reflect an undefined detrimental effect of alpha-thalassemia, possibly on the whole blood viscosity or on sickle RBC membrane-mediated adherence phenomena.


Assuntos
Anemia Falciforme/sangue , Anemia Falciforme/complicações , Eritrócitos Anormais/patologia , Talassemia/sangue , Anemia Falciforme/genética , Contagem de Eritrócitos , Índices de Eritrócitos , Eritrócitos Anormais/fisiologia , Genes Reguladores , Globinas/genética , Hemoglobina Falciforme/metabolismo , Humanos , Substâncias Macromoleculares , Fragilidade Osmótica , Talassemia/complicações , Talassemia/genética
16.
Proc Natl Acad Sci U S A ; 75(10): 4793-7, 1978 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-217000

RESUMO

We have isolated from vaccinia virus cores an enzyme, 5'-phosphate-polyribonucleotide kinase, that in the presence of ATP and Mg2+ catalyzes the conversion of 5'-phosphate and 5'-diphosphate termini of RNA to the 5'-triphosphate species. With the exception of dATP, other nucleoside triphosphates were inactive as phosphate donors; activity with dATP was 10% of that observed with ATP. The purified enzyme did not phosphorylate 5'-hydroxyl- or 5'-monophosphate-terminated polydeoxyribonucleotides, although a variety of 5'- monophosphate-terminated RNA chains were active as phosphate acceptors. By using a coupled system of 5'-phosphate-polyribonucleotide kinase and guanylyltransferase in the presence of ATP, GTP, Mg2+, and S-adenosylmethionine, capping of 5'-P-, 5'-PP-, and 5'-PPP-RNA was demonstrated; in the absence of 5'-phosphate-polyribonucleotide kinase only 5'-PPP-RNA was capped by guanylyltransferase.


Assuntos
Fosfotransferases/metabolismo , RNA/metabolismo , Trifosfato de Adenosina/metabolismo , Nucleotídeos de Desoxiadenina/metabolismo , Guanosina Trifosfato , Magnésio/metabolismo , Nucleotidiltransferases/metabolismo , Fosforilação , Fosfotransferases (Aceptor do Grupo Fosfato) , Polirribonucleotídeos , Especificidade por Substrato , Vaccinia virus/enzimologia
17.
J Biol Chem ; 253(12): 4481-9, 1978 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-659428

RESUMO

GTP:RNA guanylyltransferase, the enzyme which catalyzes the guanylylation of the 5' termini of viral mRNAs, has been isolated and purified approximately 10,000-fold from cores of vaccinia virus. S-adenosyl-methionine:mRNA (guanine-7)-methyltransferase copurified with guanylyltransferase activity through chromatography on DNA agarose, phosphocellulose, and centrifugation in glycerol gradients, suggesting that the two activities are closely associated. The molecular weight of native guanylyltransferase- and 7-methyltransferase-associated activities was approximately 120,000 as determined by glycerol gradient centrifugation. Guanylytransferase purified by electrophoresis on polyacrylamide gels at pH 4.5 lacked 7-methyltransferase activity. Analysis by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels of electrophoretically purified native guanylyltransferase showed the presence of one major band of polypeptide which had a molecular weight of approximately 59,000.


Assuntos
Nucleotidiltransferases/isolamento & purificação , Vaccinia virus/enzimologia , Nucleotídeos de Guanina , Metiltransferases/isolamento & purificação , Metiltransferases/metabolismo , Nucleotidiltransferases/metabolismo , RNA Mensageiro , Vírion/enzimologia
19.
Cold Spring Harb Symp Quant Biol ; 39 Pt 2: 1033-41, 1975.
Artigo em Inglês | MEDLINE | ID: mdl-169005

RESUMO

In this report we have presented evidence that viral sequences in the genome of AMV-infected myeloblasts can be transcribed in vitro. The RNA products synthesized in either nuclei isolated from these cells or by eukaryotic RNA polymerase B from the isolated chromatin contained approximately 1% virus-specific sequences. This result, which is in agreement with the fraction of viral RNA in infected cells (Garapin et al. 1971), is higher than expected from a random transcription of the genome, and thus shows that a degree of selectivity in transcription is maintained in both systems. The inhibition of synthesis of viral sequences in nuclei by alpha-amanitin as well as the finding that RNA polymerase B catalyzed the synthesis of viral sequences from chromatin support the hypothesis that the expression of viral information is mediated by nucleoplasmic RNA polymerase. An investigation of the properties of the chromatin-directed products led to the suggestion that RNA synthesis in vitro was initiated on single-stranded or denatured regions of the template; a limiting factor in the synthesis of large molecular weight RNA from isolated chromatin appeared to be the extent of the denatured region available to the enzyme. These findings are consistent with the suggestion that gene activation in eukaryotic organisms results from the unwinding of segments of chromatin DNA (Crick 1971).


Assuntos
Vírus da Leucose Aviária/metabolismo , Vírus da Mieloblastose Aviária/metabolismo , Cromatina/metabolismo , DNA Viral/metabolismo , RNA Viral/biossíntese , Transcrição Gênica , Amanitinas/farmacologia , Animais , Núcleo Celular/metabolismo , Sistema Livre de Células , Células Cultivadas , Galinhas , DNA Viral/biossíntese , RNA Polimerases Dirigidas por DNA/metabolismo , Depressão Química , Peso Molecular , RNA Viral/análise , RNA Viral/metabolismo , Transcrição Gênica/efeitos dos fármacos
20.
Proc Natl Acad Sci U S A ; 72(1): 194-9, 1975 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1090933

RESUMO

RNA transcribed in vitro from myeloblast chromatin by exogenously added RNA polymerase B predominantly consists of short chains that remain in hybrid structure with the template; the remainder of the product is free RNA of heterogeneous size. Addition of polyanions during synthesis caused an increase in the size and amount of free RNA with a concomitant decrease in the proportion of small RNA. The large molecular weight RNA is derived from the short RNA chains, which are synthesized de novo during the reaction in vitro. The effect of polyanions on the size and nature of the product may be related to structural changes induced in the template rather than to an inhibition of nuclease activity.


Assuntos
Cromatina/metabolismo , RNA Viral/biossíntese , Animais , Vírus da Mieloblastose Aviária/metabolismo , Centrifugação com Gradiente de Concentração , Galinhas , DNA de Cadeia Simples/metabolismo , DNA Viral/metabolismo , RNA Polimerases Dirigidas por DNA/metabolismo , Escherichia coli , Vírus da Leucemia Murina de Friend , Células HeLa , Heparina/farmacologia , Humanos , Peso Molecular , Conformação de Ácido Nucleico , Biossíntese de Proteínas , Moldes Genéticos , Transcrição Gênica
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