RESUMO
Direct injection of the vascular endothelial growth factor (VEGF) gene plasmid DNA into the myocardium was shown to induce development of new blood vessels to increase the circulation in the heart of patients with coronary artery diseases. However, such angiogenic gene therapy (via naked DNA) was limited by low level of gene expression. Furthermore, the temporal and spatial characteristics of VEGF gene transfer in the heart are not known. In this study, we demonstrated that a plasmid vector, containing the human cytomegalovirus immediate early (HCMV IE) promoter and enhancer, induces greater expression of gene in the rat heart monitored by gene fused to the chloramphenicol acetyl transferase (CAT) reporter, than four different viral and cellular promoters. Interestingly, expression of VEGF121 protein showed an earlier peak, a shorter duration, and a wider distribution than that of CAT only. Therefore, a plasmid vector with an HCMV IE promoter/enhancer provides clear advantages over other previously developed plasmids. Furthermore, expression profile of VEGF121 gene may provide useful information in the design of angiogenic gene therapy in the heart
Assuntos
Animais , Masculino , Ratos , Cloranfenicol O-Acetiltransferase/análise , Estudo Comparativo , Citomegalovirus/genética , DNA Viral/administração & dosagem , Fatores de Crescimento Endotelial/análise , Elementos Facilitadores Genéticos , Regulação Viral da Expressão Gênica , Fusão Gênica , Técnicas de Transferência de Genes , Genes Virais , Vetores Genéticos , Peptídeos e Proteínas de Sinalização Intercelular/análise , Linfocinas/análise , Miocárdio/metabolismo , Plasmídeos/genética , Regiões Promotoras Genéticas , Ratos Sprague-Dawley , Fatores de Tempo , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
Direct injection of the vascular endothelial growth factor (VEGF) gene plasmid DNA into the myocardium was shown to induce development of new blood vessels to increase the circulation in the heart of patients with coronary artery diseases. However, such angiogenic gene therapy (via naked DNA) was limited by low level of gene expression. Furthermore, the temporal and spatial characteristics of VEGF gene transfer in the heart are not known. In this study, we demonstrated that a plasmid vector, containing the human cytomegalovirus immediate early (HCMV IE) promoter and enhancer, induces greater expression of gene in the rat heart monitored by gene fused to the chloramphenicol acetyl transferase (CAT) reporter, than four different viral and cellular promoters. Interestingly, expression of VEGF121 protein showed an earlier peak, a shorter duration, and a wider distribution than that of CAT only. Therefore, a plasmid vector with an HCMV IE promoter/enhancer provides clear advantages over other previously developed plasmids. Furthermore, expression profile of VEGF121 gene may provide useful information in the design of angiogenic gene therapy in the heart
Assuntos
Animais , Masculino , Ratos , Cloranfenicol O-Acetiltransferase/análise , Estudo Comparativo , Citomegalovirus/genética , DNA Viral/administração & dosagem , Fatores de Crescimento Endotelial/análise , Elementos Facilitadores Genéticos , Regulação Viral da Expressão Gênica , Fusão Gênica , Técnicas de Transferência de Genes , Genes Virais , Vetores Genéticos , Peptídeos e Proteínas de Sinalização Intercelular/análise , Linfocinas/análise , Miocárdio/metabolismo , Plasmídeos/genética , Regiões Promotoras Genéticas , Ratos Sprague-Dawley , Fatores de Tempo , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
BACKGROUND & OBJECTIVES: Haemophilus influenzae causes a variety of life threatening infections in humans. Early detection of antimicrobial resistance is of importance in the treatment and management of infection. The modified Slack's method, a simple assay, has been evaluated in this study for the early detection of chloramphenicol resistance. METHODS: Fifty isolates of H. influenzae from invasive and non-invasive sites were included. Antimicrobial susceptibility testing was done by disc diffusion method and minimum inhibitory concentration (MIC) determination was performed for chloramphenicol only. Modified Slack's method was used to test for the production of chloramphenicol acetyl transferase (CAT). RESULTS: Invasive isolates showed higher degree of resistance to chloramphenicol (72%) compared to non-invasive ones (28%). One hundred per cent association was found between results of disc diffusion, MIC and CAT production amongst strains resistant to chloramphenicol. INTERPRETATION & CONCLUSION: The findings suggested that chloramphenicol still remains the drug of choice for treatment for non-invasive infection caused by H. influenzae. Modified Slack's method is a simple, rapid, inexpensive and reliable method for the detection of chloramphenicol resistance amongst H. influenzae.