RESUMEN
BACKGROUND: Body size is associated with increased brachial systolic blood pressure (SBP) and aortic stiffness. The aims of this study were to determine the relationships between central SBP and body size (determined by body mass index (BMI), waist circumference and waist/hip ratio) in health and disease. We also sought to determine if aortic stiffness was correlated with body size, independent of BP. METHODS: BMI, brachial BP and estimated central SBP (by SphygmoCor and radial P2) were recorded in controls (n=228), patients with diabetes (n=211), coronary artery disease (n=184) and end-stage kidney disease (n=68). Additional measures of waist circumference and arterial stiffness (aortic and brachial pulse wave velocity (PWV)) were recorded in a subgroup of 75 controls (aged 51 ± 12 years) who were carefully screened for factors affecting vascular function. RESULTS: BMI was associated with brachial (r=0.30; P<0.001) and central SBP (r=0.29; P<0.001) in the 228 controls, but not the patient populations (r<0.13; P>0.15 for all comparisons). In the control subgroup, waist circumference was also significantly correlated with brachial SBP (r=0.29; P=0.01), but not central SBP (r=0.22; P=0.07). Independent predictors of aortic PWV in the control subgroup were brachial SBP (ß=0.43; P<0.001), age (ß=0.37; P<0.001), waist circumference (ß=0.39; P=0.02) and female sex (ß=-0.24; P=0.03), but not BMI. CONCLUSION: In health, there are parallel increases in central and brachial SBP as BMI increases, but these relationships are not observed in the presence of chronic disease. Moreover, BP is a stronger correlate of arterial stiffness than body size.
Asunto(s)
Presión Sanguínea , Índice de Masa Corporal , Enfermedades Cardiovasculares/fisiopatología , Diabetes Mellitus Tipo 2/fisiopatología , Fallo Renal Crónico/fisiopatología , Rigidez Vascular , Velocidad del Flujo Sanguíneo , Arteria Braquial/fisiopatología , Enfermedades Cardiovasculares/sangre , Enfermedades Cardiovasculares/epidemiología , Enfermedad Crónica , Estudios Transversales , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/epidemiología , Ecocardiografía , Femenino , Humanos , Fallo Renal Crónico/sangre , Fallo Renal Crónico/epidemiología , Masculino , Manometría , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Flujo Pulsátil , Factores de Riesgo , Esfigmomanometros , Circunferencia de la Cintura , Relación Cintura-CaderaRESUMEN
The X-ray crystal structure of the apo-form of the Fur protein from Rhizobium leguminosarum has been solved at 2.7 A resolution. Small-angle X-ray scattering was used to give information on the solution conformation of the protein. The Fur homodimer folds into two domains. The N-terminal domain is formed from the packing of two helix-turn-helix motifs while the C-terminal domain appears primarily to stabilize the dimeric state of the protein.