Carotid wave analysis in young adults with a history of adolescent anorexia nervosa: a case control study.

BACKGROUND: Anorexia nervosa (AN) is associated with abnormalities that may increase the risk of future cardiovascular disease. This study assessed the cardiovascular health of individuals who recovered from AN during adolescence by conducting wave power analysis. METHODS: Former AN patients discharged from the Royal Children's and Monash Children's Hospitals (N = 17) in Melbourne, Australia underwent ultrasound imaging of the right carotid artery. Wave power analysis was conducted to assess biomechanical interactions of the cardiovascular system. Patient measures were compared to healthy controls (N = 51). RESULTS: Eighty-eight percent of the former AN patients and controls were female, aged approximately 25 years, with a healthy body mass index. Mean carotid flow and pulsatility index were not different between groups. Carotid arterial strain and distensibility were lower, and the wave speed and beta stiffness index higher in the former AN patients. Characteristic impedance was not different nor were the forward and backward wave amplitudes. However, wave reflection indices (ratios of backward-to-forward compression wave area, and wave-related effect on pressure and hydraulic power) were 12-18% lower in the former AN patients (p < 0.05). CONCLUSIONS: Increased carotid artery stiffness and reduced wave reflection are evident in young adults who recovered from adolescent AN. This may relate to an adaptive process that helps to maintain or restore flow and characteristic impedance despite increased vessel stiffness, with this warranting future investigation.

Anorexia nervosa (AN) is an eating disorder which may cause permanent changes in the heart and blood vessels. Blood flow properties can provide information on the health of a patient's heart and blood vessels. In this study of young adults who recovered from adolescent AN, blood flow analysis revealed altered properties compared to controls who had never experienced an eating disorder. These alterations may help to maintain or restore blood flow despite unhealthy changes in the blood vessels themselves. Further investigation is needed to better understand how the heart and blood vessels change during and after AN to guide treatments and ongoing care. Regular assessment of the heart and blood vessels after AN recovery could identify and monitor possible health risks early.

Long-term cardiovascular consequences of adolescent anorexia nervosa.

BACKGROUND: Anorexia nervosa (AN) is associated with maladaptive cardiovascular changes. This study investigated whether individuals who recovered from AN during adolescence experience long-term cardiovascular risk in early adulthood. METHODS: Former AN patients discharged from the Royal Children's and Monash Children's Hospital Eating Disorder Services in Melbourne, Australia underwent cardiovascular testing. Measurements were performed using an oscillometric device for blood pressure and pulse wave velocity, ultrasound for carotid wall structure/function, resting electrocardiogram for heart-rate variability, and the EndoPat 2000 (Itamar) system for endothelial function. Patient measures were compared to healthy controls and/or normal thresholds. RESULTS: Ninety-one percent of the former AN patients (N = 22) and controls (N = 66) were female, aged approximately 25 years, with a healthy body mass index. The mean time interval from AN recovery to participation was 7.4 years. Pulse wave velocity was lower in the former AN patients than controls. Carotid intima-media thickness was not different; however, carotid distensibility and compliance were lower, and the elastic modulus higher in the former AN patients. Greater vagal tone was observed and endothelial dysfunction was evident in 46% of the former patients. CONCLUSIONS: Young adults who recovered from adolescent AN exhibit persistent cardiovascular adaptations. Routine cardiovascular monitoring could manage potential disease risk. IMPACT: Cardiovascular complications are common in patients with anorexia nervosa (AN) and population studies have revealed that developmental adaptations in response to undernutrition have long-term consequences for cardiovascular health. In this study of young adults treated for AN during adolescence, there was evidence of increased carotid artery stiffness, reduced aortic stiffness, vagal hyperactivity, and endothelial dysfunction in early adulthood when compared to healthy controls. It is important to consider the cardiovascular health of patients with AN beyond achieving medical stability. Interventions that monitor cardiovascular health could minimise the burden of future cardiovascular disease.

Response of pre-crystallized CAD/CAM zirconia-reinforced lithium silicate glass ceramic to cyclic nanoindentation.

This paper reports on a cyclic nanoindentation approach of a pre-crystallized zirconia-reinforced lithium silicate glass ceramic (ZLS) to understand its material behavior associated with its machinability in dental CAD/CAM diamond abrasive milling. The material response to the cyclic nanoindentation using a Berkovich diamond tip was quantitatively determined in terms of the indentation contact hardness, elastic modulus, elasticity and plasticity for each loading cycle at peak loads of 2.5-10 mN. The cyclic load-displacement curves at different load levels indicate discrete discontinuities and hysteresis loops, which might have arisen from viscoelasticity behavior. Material properties degraded with an increasing number of loading cycles due to the mechanical softening which may facilitate machining in dental CAD/CAM milling. Elastic and plastic displacements and indentation energies revealed the pre-crystallized ZLS experiences predominantly elastic deformation and thus has a high capacity to retain its structure and shape. Furthermore, elastic energy dominated cyclic loading led to pseudoelasticity due to plastic strain accumulation. In situ scanning probe microscopy (SPM) images of cyclic indentation imprints reveal the fracture-free plastic deformation of the pre-crystallized ZLS under cyclic nanoindentation conditions. The outcomes of this study provide the mechanics model of diamond milling of the pre-crystallized ZLS due to the cyclic loading nature of dental CAD/CAM abrasive processing.

Nano-scale mechanical behavior of pre-crystallized CAD/CAM zirconia-reinforced lithium silicate glass ceramic.

This paper reports on the mechanical behavior of pre-crystallized CAD/CAM zirconia-reinforced lithium silicate glass ceramic (ZLS) using nanoindentation with a Berkovich diamond tip and in situ scanning probe microscopy (SPM). The indentation contact hardness, the elastic modulus, and the elasticity and plasticity of the material were determined using the Oliver-Pharr method, the Sakai model and the Meyer's law at peak loads of 2.5-10 mN and a loading rate of 0.5 mN/s. The load-displacement curves at all applied loads indicate that ZLS deformed plastically without fracture. The discrete discontinuities in the load-displacement curves might have arisen from the shear plane activation for plastic deformation. The measured hardness and elastic modulus were load-independent (ANOVA, p > 0.05), in ranges of 8.17 ±â€¯1.23 GPa to 9.86 ±â€¯1.24 GPa and 98.55 ±â€¯7.38 GPa to 105.78 ±â€¯9.98 GPa, respectively. The resistance to plasticity of ZLS significantly showed a second-order polynomial load relationship or a power law load dependency. Meanwhile, both the elastic and plastic displacements also significantly revealed power law load dependencies. However, the elastic and plastic deformation components were load-independent. Increased indentation loads resulted in significant decreases in the normalized elastic strain energy (p < 0.05) accompanied by significant increases in the normalized indentation absorbed energy (p < 0.05). The equivalent elasticity and plasticity of ZLS during indentation occurred at 7.5 mN. The outcomes of this study provide insights into fabrication and mechanical functions of ZLS restorations, particularly facilitating abrasive machining in dental CAD/CAM processing in the ductile regime.