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- Andersson, Bert, 1952, et al.
(author)
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Angiotensin-II type 1 receptor gene polymorphism and long-term survival in patients with idiopathic congestive heart failure.
- 1999
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In: European journal of heart failure. - 1388-9842. ; 1:4, s. 363-9
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Journal article (peer-reviewed)abstract
- It has been suggested that a genetic polymorphism in the angiotensin II type 1 receptor gene (ATRG) and the ACE gene DD genotype might have a synergistic influence on the risk of developing cardiovascular disease.To study the possible interaction between polymorphisms in the ACE gene and the ATRG, regarding survival and left ventricular function.Polymorphism of the two genes was studied in a population-based cohort of 194 patients with idiopathic heart failure, recruited from the western part of Sweden 1985-1988. The patients were investigated by echocardiography. The survival status was checked during the 7-year follow-up period.Although there was no statistically significant additive risk of the ATRG polymorphism, patients carrying the ACE gene DD genotype in combination with a C allele of the ATRG tended to have a poorer prognosis. DD +AA, OR 1.24 (95% CI 0.67-2.32, P = 0.49); DD +AC, OR 1.64 (95% CI 0.95-2.83, P = 0.08); DD + CC, OR 3.54 95% CI 0.78-16.1, P = 0.10); DD +AC/CC, OR 1.84 (95% CI 1.10-3.08, P = 0.02). Patients with the DD +AC/CC genotypes tended to have lower ejection fraction and increased left ventricular mass.There was a trend toward a worse prognosis in patients with the combination of a C-allele in the ATRG and the ACE gene DD genotype, suggesting an interaction of these two genetic polymorphisms on disease severity.
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- Drvota, V, et al.
(author)
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The effect of amiodarone on the beta-adrenergic receptor is due to a downregulation of receptor protein and not to a receptor-ligand interaction.
- 1999
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In: Biochemical and biophysical research communications. - : Elsevier BV. - 0006-291X. ; 255:2, s. 515-20
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Journal article (peer-reviewed)abstract
- Downregulation of beta adrenergic receptors (beta-AR) by amiodarone (Am) have been reported in several studies both in vivo and in vitro. The mechanism underlying the antiadrenergic effect of Am is, however, still unclear. The aim of this study was to characterize whether the antiadrenergic effect of amiodarone is due to binding to the beta-AR or to downregulation of the beta-AR receptor protein. All experiments were performed on confluent mouse AT-1 cardiomyocytes cultured for 6 days. In acute experiments, equilibrium binding with [3H]-CGP-12177 to beta-AR was not directly inhibited by Am and the equilibrium binding constant did not change during prolonged exposure up to 72 hours. After Am exposure for 48 hours beta-AR density was decreased by 26% (p<0.005). T3 partially prevented the downregulation elicited by Am (p<0.05). A Western blot analysis with beta1-AR antibodies revealed a decreased signal intensity in cells treated with Am for 48 h as compared to control (p<0.05). Isoproterenol-provoked cAMP response did not change after acute exposure to Am. After incubation for 48 hours with Am there was, however, a 20% decrease in cAMP response as compared to control (p<0.05). This study shows that the effect of Am on beta-AR is due to a downregulation of the beta-AR protein and not to a competitive or non-competitive receptor-ligand interaction. This indicates a new pharmacological mechanism for modulation of beta-AR, which probably is transcriptionally regulated.
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