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1.
Biol. Res ; 46(3): 265-273, 2013. ilus, graf, tab
Artigo em Inglês | LILACS | ID: lil-692193

RESUMO

Purpose: The G-protein β3-subunit gene C825T polymorphism (GNB3-C825T) has been reported to be associated with essential hypertension (EH), but results from previous studies are conflicting. The present study aimed at investigating the association between this polymorphism and risk of EH using a meta-analysis on the published studies. Materials and Methods: PubMed, Embase, CBM (China Biological Medicine Database), Wanfang and VIP databases were searched to identify eligible studies published in English and Chinese before March 2013. Data were extracted using standardized methods. The association was assessed by the odds ratio (OR) with 95% confidence intervals (CI). Begg's test was used to measure publication bias. Results: A total of 40 case-control studies containing 16,518 EH patients and 20,284 controls were involved in this meta-analysis. Overall, a significant association was found between GNB3 C825T polymorphism and risk of EH when all studies were pooled with a random-effects model for T versus C (OR=1.09, 95% CI: 1.04-1.19). In the subgroup analysis, the same association was found in overall Caucasian (T versus C, OR=1.16, 95% CI 1.08-1.24) and Chinese populations (TT versus CC, OR=1.23, 95% CI 1.06-1.57). No associations were detected between GNB3-C825T and the risk of EH overall in Asian and Japanese people. Conclusions: Meta-analysis results suggest that the GNB3-C825T polymorphism is associated with risk of EH in the overall population, the Caucasians and the Chinese. The effect of the variants on the expression levels and the possible functional role of the variants in EH should be addressed in further studies.


Assuntos
Humanos , Predisposição Genética para Doença/genética , Proteínas Heterotriméricas de Ligação ao GTP/genética , Hipertensão/genética , Polimorfismo Genético/genética , China , Frequência do Gene , Genótipo , Fatores de Risco
2.
Caracas; s.n; jul. 2006. 81 p. ilus, tab, graf.
Tese em Espanhol | LILACS | ID: lil-551804

RESUMO

La activación muscarínica del músculo liso traqueal de bovino (MLTB) genera de dos señales de GMPc (20 y 60s), la primera atribuida a la Guanililciclasa soluble (sGC) y la segunda a la Guanililciclasa particulada (NPR-GC). Existen evidencias que la activación muscarínica es mediada. En este sentido determinamos el efecto del tetradecapéptido desacoplante de las proteínas G Mastoparán sobre dicha activación, evaluando los niveles de GMPc y la actividad contráctil del MLTB. Mastoparán inhibió en un 63 por ciento la primera señal de GMPc y desapareció la segunda. Posteriormente evaluamos el efecto de Mastoparán sobre las sGC y NPR-GC. La enzima sGG se evalúo utilizando el Nitroprusiato de Sodio (SNP), el cual indujo un patrón bifásico de acumulación GMPc, las NPR-GC, fueron evaluadas utilizando los péptidos natriuréticos ANP y CNP-53 los cuales indujeron patrones monotónico y bifásicos respectivamente. Observando en los tres casos que la preincubación con Mastoparán, disminuyó los niveles de GMPc de manera significativa (p<0.05). Dicho efecto fue atribuido a proteínas Gi ya que al pre-tratar el MLTB con PTX desaparecía el efecto de Mastoparán. También evaluamos la actividad contráctil del MLTB, encontrándose que Mastoparán se comportan como un "inhibidor no competitivo" de la contracción muscarínica, sin comprometer la integridad funcional de la maquinaria contráctil ya que las aminas biogenas histamina y serotonina produjeron potentes contracciones. Estos hallazgos nos sugieren que la inhibición selectiva de las señales de GMPc esta relacionada con el bloqueo de la contracción muscarínica.


Assuntos
Animais , Guanilato Ciclase , Proteínas Heterotriméricas de Ligação ao GTP , Músculo Liso , Peptídeos , Receptores Muscarínicos , Venenos de Vespas , Fisiologia
3.
Mem. Inst. Oswaldo Cruz ; 97(suppl.1): 77-84, Oct. 2002. ilus, tab
Artigo em Inglês | LILACS | ID: lil-325040

RESUMO

The human nuclear protein RbAp48 is a member of the tryptophan/aspartate (WD) repeat family, which binds to the retinoblastoma (Rb) protein. It also corresponds to the smallest subunit of the chromatin assembly factor and is able to bind to the helix 1 of histone H4, taking it to the DNA in replication. A cDNA homologous to the human gene RbAp48 was isolated from a Schistosoma mansoni adult worm library and named SmRbAp48. The full length sequence of SmRbAp48 cDNA is 1036 bp long, encoding a protein of 308 amino acids. The transcript of SmRbAp48 was detected in egg, cercariae and schistosomulum stages. The protein shows 84% similarity with the human RbAp48, possessing four WD repeats on its C-terminus. A hypothetical tridimensional structure for the SmRbAp48 C-terminal domain was constructed by computational molecular modeling using the b-subunit of the G protein as a model. To further verify a possible interaction between SmRbAp48 and S. mansoni histone H4, the histone H4 gene was amplified from adult worm genomic DNA using degenerated primers. The gene fragment of SmH4 is 294 bp long, encoding a protein of 98 amino acids which is 100% identical to histone H4 from Drosophila melanogaster


Assuntos
Animais , Humanos , Proteínas de Helminto , Histonas , Proteínas Nucleares , Schistosoma mansoni , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , DNA Complementar , Expressão Gênica , Biblioteca Gênica , Genes de Helmintos , Proteínas Heterotriméricas de Ligação ao GTP , Estágios do Ciclo de Vida , Dados de Sequência Molecular , Schistosoma mansoni
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