In vivo estimation of the contribution of elastin and collagen to the mechanical properties in the human abdominal aorta: effect of age and sex

Astrand H, Stalhand J, Karlsson J, Karlsson M, Sonesson B, Lanne T. In vivo estimation of the contribution of elastin and collagen to the mechanical properties in the human abdominal aorta: effect of age and sex. J Appl Physiol 110: 176-187, 2011. First published November 11, 2010; doi:10.1152/japplphysiol.00579.2010.-The mechanical properties of the aorta affect cardiac function and are related to cardiovascular morbidity/mortality. This study was designed to evaluate the isotropic (mainly elastin, elastin(iso)) and anisotropic (mainly collagen, collagen(ani)) material parameters within the human aorta in vivo. Thirty healthy men and women in three different age categories (23-30, 41-54, and 67-72 yr) were included. A novel mechanical model was used to identify the mechanical properties and the strain field with aid of simultaneously recorded pressure and radius in the abdominal aorta. The magnitudes of the material parameters relating to both the stiffness of elastin(iso) and collagen(ani) were in agreement with earlier in vitro studies. The load-bearing fraction attributed to collagen(ani) oscillated from 10 to 30% between diastolic and systolic pressures during the cardiac cycle. With age, stiffness of elastin(iso) increased in men, despite the decrease in elastin content that has been found due to elastolysis. Furthermore, an increase in stiffness of collagen(ani) at high physiological pressure was found. This might be due to increased glycation, as well as changed isoforms of collagen in the aortic wall with age. A marked sex difference was observed, with a much less age-related effect, both on elastin(iso) and collagen(ani) stiffness in women. Possible factors of importance could be the effect of sex hormones, as well as differing collagen isoforms, between the sexes

Validation of reported dentoalveolar relationships in the Swedish Quality Registry for Cleft Lip and Palate

Objectives: The present study validated data that had been reported to the Swedish Quality Registry for Cleft Lip and Palate (CLP) under new requirements from 2016, when use of the 5-year-old (5YO) and the Modified Huddart and Bodenham (MHB) indices for rating occlusion in children born with unilateral CLP (UCLP) was introduced. Materials and methods: The sample included blinded study casts (n = 97) and photos (n = 4) of 5-year-old children who had been born with UCLP in 2009−2011 and were enrolled at one of six cleft centres in Sweden. Fourteen orthodontists from the centres assessed the patients (n = 101) using the 5YO and the MHB indices. Median 5YO and MHB scores of the 14 assessments were compared with original registry data (n = 61). Each centre devised code keys to protect the identities of their patients in the registry. Results: Interrater agreement among the 14 orthodontists was good for the 5YO index (quadratic-weighted kappa: 0.72−0.92) and the MHB index (intraclass correlation coefficient: 0.991−0.994). Comparisons of median 5YOs for each identifiable child with their registry data (n = 61) found total agreement for 70.5 per cent. Comparisons between median MHBs and registry data showed very good or good agreement in 93.4 per cent of the cases. Limitations: Two teams lost their code keys, which reduced the sample to 61 patients. Conclusions: The dentoalveolar outcome data in the CLP registry was trustworthy. There was good agreement among the Swedish cleft teams assessing the 5YO and MHB indices in children born with UCLP at age 5 years