Universal features of the order-parameter fluctuations : reversible and irreversible aggregation

We discuss the universal scaling laws of order parameter fluctuations in any system in which the second-order critical behaviour can be identified. These scaling laws can be derived rigorously for equilibrium systems when combined with the finite-size scaling analysis. The relation between order parameter, criticality and scaling law of fluctuations has been established and the connexion between the scaling function and the critical exponents has been found. We give examples in out-of-equilibrium aggregation models such as the Smoluchowski kinetic equations, or of at-equilibrium Ising and percolation models.Comment: 19 pages, 10 figure

Gamma-glutamyltransferase, arterial remodeling and prehypertension in a healthy population at low cardiometabolic risk

Plasma gamma-glutamyltransferase (GGT) was suggested to reflect the level of systemic oxidative stress. Oxidative stress induces changes in arterial structure and function and contributes to the development of hypertension. Therefore, GGT may be associated with arterial remodeling and blood pressure (BP) increment, even in absence of disease. To test this hypothesis, we evaluated, in 825 healthy subjects at low cardiometabolic risk, the associations of plasma GGT with carotid artery intima-media thickness (IMT), luminal diameter and prehypertension; in 154 subjects was evaluated also the association with aortic stiffness (cfPWV). Associations were controlled for insulin sensitivity, C-reactive protein, and life-style habits. In the main population, BP was remeasured after 3 years. Carotid diameter and cfPWV, but not IMT, were directly and independently related to plasma GGT. Subjects with prehypertension (N = 330) had higher GGT as compared with subjects with normal BP (22 [14] vs 17 [11] IU/L; adjusted P = 0.001), and within prehypertensive subjects, those who developed hypertension during 3 years had higher GGT than those without incident hypertension (27 [16] vs 21 [14] IU/L; adjusted P < 0.05). Within subjects with arterial stiffness measurement, those with prehypertension (N = 79) had higher both GGT and arterial stiffness (25 [14] vs 16 [20] IU/L and 9.11 ± 1.24 vs 7.90 ± 0.94 m/s; adjusted P < 0.01 and <0.05). In the view of previous evidence linking plasma GGT concentration to the level of systemic oxidative stress, our findings suggest a role of oxidative stress in subclinical arterial damage and in prehypertension, even in healthy subjects free of cardiometabolic risk. Arterial organ damage may represent the link between GGT and hypertension. © 2020, The Author(s), under exclusive licence to Springer Nature Limited

Ethnic-specific normative reference values for echocardiographic la and LV size, LV mass, and systolic function: The EchoNoRMAL study

Abstract OBJECTIVES: This study sought to derive age-, sex-, and ethnic-appropriate adult reference values for left atrial (LA) and left ventricular (LV) dimensions and volumes, LV mass, fractional shortening, and ejection fraction (EF) derived from geographically diverse population studies. BACKGROUND: The current recommended reference values for measurements from echocardiography may not be suitable to the diverse world population to which they are now applied. METHODS: Population-based datasets of echocardiographic measurements from 22,404 adults without clinical cardiovascular or renal disease, hypertension, or diabetes were combined in an individual person data meta-analysis. Quantile regression was used to derive reference values at the 95th percentile (upper reference value [URV]) and fifth percentile (lower reference value [LRV]) of each measurement against age (treated as linear), separately within sex and ethnic groups. RESULTS: The URVs for left ventricular end-diastolic volume (LVEDV), LV end-systolic volume, and LV stroke volume (SV) were highest in Europeans and lowest in South Asians. Important sex and ethnic differences remained after indexation by body surface area or height for these measurements, as well as for the LRV for SV. LVEDV and SV decreased with increasing age for all groups. Importantly, the LRV for EF differed by ethnicity; there was a clear apparent difference between Europeans and Asians. The URVs for LV end-diastolic diameter and LV end-systolic diameter were higher for Europeans than those for East Asian, South Asian, and African people, particularly among men. Similarly, the URVs for LA diameter and volume were highest for Europeans. CONCLUSIONS: Sex- and/or ethnic-appropriate echocardiographic reference values are indicated for many measurements of LA and LV size, LV mass, and EF. Reference values for LV volumes and mass also differ across the age range

The effect of menopause on carotid artery remodeling, insulin sensitivity, and plasma adiponectin in healthy women

Background: The mechanisms by which menopause may influence the systemic subclinical atherosclerosis are unexplained. The aim of this cross-sectional study was to evaluate the associations between early menopause, established cardiovascular (c-v) risk factors, metabolic parameters (insulin secretion and sensitivity, plasma adiponectin), and carotid intima-media thickness (IMT) in healthy women. Methods: In 74 menopausal women (mean age = 51 ± 3 years, mean duration of menopause = 2.9 ± 1.2 years) and in 74 nonmenopausal women comparable for age and body mass index (BMI), common carotid artery (CCA) luminal diameter, and IMT in different carotid segments were measured in digitized ultrasound images. Insulin sensitivity and secretion were assessed using the euglycemic hyperinsulinemic clamp technique and oral glucose tolerance test (OGTT). Insulin secretion was reconstructed by mathematical modeling. Results: CCA diameter (5.55 ± 0.46 vs. 5.21± 0.51 mm, P < 0.001), CCA IMT (608 ± 78 vs. 576 ± 74 νm, P < 0.01) and systolic blood pressure (BP) (117 ± 12 vs. 113 ± 11 mm Hg, P < 0.05) were higher in menopausal women, whereas CCA IMT/diameter ratio and IMT in other carotid segments did not differ between the groups. By multivariate models, independent predictors of CCA diameter were menopause and body weight (cumulative R2= 0.37) and independent correlates of CCA IMT were luminal diameter, systolic BP and low-density lipoprotein (LDL) cholesterol (cumulative R2= 0.48). Fasting insulin, insulin secretion, and sensitivity and plasma adiponectin were similar in the two groups and were not related to carotid IMT. Conclusions: Early menopause is associated with CCA remodeling, characterized by a proportional increase in luminal diameter and wall thickness, independent of atherosclerotic risk factors and metabolic variables. © 2009 American Journal of Hypertension, Ltd