Three-dimensional numerical simulation of blood flow in mouse aortic arch around atherosclerotic plaques

Atherosclerosis is a progressive disease, involving the build-up of lipid streaks in artery walls, leading to plaques. Understanding the development of atherosclerosis and plaque vulnerability is critically important since plaque rupture can result in heart attack or stroke. Plaques can be divided into two distinct types: those likely to rupture (vulnerable) or less likely to rupture (stable). In the last decade, researchers have been interested in studying the influence of the mechanical effects (blood shear stress, pressure forces and structural stress) on the plaque formation, progression and rupture processes but no general agreement has been found. The purpose of the present work is to include more realistic conditions for the numerical calculations of the blood flow by implementing real geometries with plaques in the numerical model. Hemodynamical parameters are studied in both diseased and healthy configurations. The healthy configuration is obtained by removing numerically the plaques from three dimensional geometries obtained by micro-computed tomography. A new hemodynamical parameter is also introduced to relate the location of plaques to the characteristics of the flow in the healthy configuration. © 2014 .

Maternal and neonatal influences on, and reproducibility of, neonatal aortic pulse wave velocity

Aortic pulse wave velocity (aPWV), a noninvasive measure of vascular stiffness, is an independent predictor of cardiovascular disease both before and in overt vascular disease. Its characteristics in early life and its relationship to maternal factors have hardly been studied. To test the hypothesis that infant aPWV was positively related to maternal anthropometry and blood pressure (BP) at 28 weeks gestation, after adjusting for neonatal anthropometry and BP, 148 babies born in Manchester were measured 1 to 3 days after birth. A high reproducibility of aPWV, assessed in 30 babies within 3 days of birth, was found with a mean difference between occasions of –0.04 m/s (95% CI: –0.08 to 0.16 m/s). Contrary to our hypothesis, a significant inverse relation was found between neonatal aPWV (mean: 4.6 m/s) and maternal systolic BP (mean: 108.9 mm Hg; r=–0.57; 95% CI: –0.67 to –0.45) but not maternal height nor weight. Neonatal aPWV was positively correlated with birth length, birth weight, and systolic BP. In multiple regression, neonatal aPWV remained significantly inversely associated with maternal systolic BP (adjusted ß coefficient: –0.032; 95% CI: –0.040 to –0.024; P<0.001), after adjustment for maternal age, birth weight, length, and neonatal BP (all independently and positively related to aPWV) and for gestational age, maternal weight, and height (unrelated). These results suggest that infant aPWV may be a useful index of infant vascular status, is less disturbing to measure than infant BP, and is sensitive to the gestational environment marked by maternal BP.

Current developments and future challenges for the creation of aortic heart valve

The concept of tissue-engineered heart valves offers an alternative to current heart valve replacements that is capable of addressing shortcomings such as life-long administration of anticoagulants, inadequate durability, and inability to grow. Since tissue engineering is a multifaceted area, studies conducted have focused on different aspects such as hemodynamics, cellular interactions and mechanisms, scaffold designs, and mechanical characteristics in the form of both in vitro and in vivo investigations. This review concentrates on the advancements of scaffold materials and manufacturing processes, and on cell–scaffold interactions. Aside from the commonly used materials, polyglycolic acid and polylactic acid, novel polymers such as hydrogels and trimethylene carbonate-based polymers are being developed to simulate the natural mechanical characteristics of heart valves. Electrospinning has been examined as a new manufacturing technique that has the potential to facilitate tissue formation via increased surface area. The type of cells utilized for seeding onto the scaffolds is another factor to take into consideration; currently, stem cells are of great interest because of their potential to differentiate into various types of cells. Although extensive studies have been conducted, the creation of a fully functional heart valve that is clinically applicable still requires further investigation due to the complexity and intricacies of the heart valve.

Repairing the rupture : restorative justice and the rehabilitation of offenders

Restorative justice is a social justice movement that aims to deal with consequences of crime through repairing and restoring relationships of three key stakeholders: victims, offenders, and communities. Unfortunately, it is often unclear where offender rehabilitation fits within the constructs of repair and reintegration that drive this justice paradigm. An analysis of the relationship between restorative justice theory and offender rehabilitation principles reveals tensions between the two normative frameworks and a lack of appreciation that correctional treatment programs have a legitimate role alongside restorative practices. First, we outline the basic tenets of the Risk–Need–Responsivity Model and the Good Lives Model in order to provide a brief overview of two recent models of offender rehabilitation. We then consider the claims made by restorative justice proponents about correctional rehabilitation programs and their role in the criminal justice system. We conclude that restorative justice and rehabilitation models are distinct, although overlapping, normative frameworks and have different domains of application in the criminal justice system, and that it is a mistake to attempt to blend them in any robust sense.

Effects of electric fields on pollen rupture

RATIONALE: To determine whether the potential for previous termpollennext term fragmentation is increased during thunderstorms by exploring the previous termeffectsnext term of previous termelectricnext termprevious termfieldsnext term, with magnitude as found in the outdoor environment.

METHODS: Fresh previous termpollennext term grains were collected from bermudagrass flowers. A light microscope was modified with the addition of an previous termelectricnext termprevious termfieldnext term generated from a DC source (0-20 V) that was applied to the stage. Water was added to test for previous termpollennext termprevious termrupturenext term and to assess previous termpollennext term viability.

RESULTS: Bermuda grass previous termpollennext term did not previous termrupturenext term within 1 h of contact with water. Only after exposure to an previous termelectricnext termprevious termfieldnext term did Bermudagrass previous termpollennext term show a considerable amount of rupturing immediately upon immersion in water. The higher the voltage the previous termpollennext term is exposed to before coming into contact with water, the higher the percentage of previous termrupturenext term of the previous termpollennext term. previous termElectricnext termprevious termfieldsnext term, generated in the laboratory and of magnitude found during thunderstorms, affected the previous termpollennext term after as little as a 5 s exposure. The highest percentage of previous termrupturenext term occurred after exposures of at least 10 s: 80% previous termrupturenext term occurred after 10 s exposure at 10kVolts/m. This previous termeffectnext term is sustained for at least 15 min.

CONCLUSIONS: Thunderstorm regularly generate previous termelectricnext termprevious termfieldsnext term up to 5 kV/m in strength, and can reach 10kV/m, and cover several km in distance. The magnitude of the previous termelectricnext termprevious termfieldsnext term that affects the previous termpollennext term grains in the laboratory is low enough to be commonly found in the outdoor environment during thunderstorms. These previous termelectricnext termprevious termfields prime previous termpollen grains for more rapid release of allergenic particles.

Birch pollen rupture and the release of aerosols of respirable allergens

Backgound Birch pollen allergens have been implicated as asthma triggers; however, pollen grains are too large to reach the lower airways where asthmatic reactions occur. Respirable-sized particles containing birch pollen allergens have been detected in air filters, especially after rainfall but the source of these particles has remained speculative.

Objective To determine the processes by which birch pollen allergens become airborne particles of respirable size with the potential to contribute to airways inflammation.

Methods Branches with attached male catkins were harvested and placed in a controlled emission chamber. Filtered dry air was passed through the chamber until the anthers opened, then they were humidified for 5 h and air-dried again. Flowers were disturbed by wind generated from a small electric fan. Released particles were counted, measured and collected for immuno-labelling and high-resolution microscopy.

Results Birch pollen remains on the dehisced anther and can rupture in high humidity and moisture. Fresh pollen takes as long as 3 h to rupture in water. Drying winds released an aerosol of particles from catkins. These were fragments of pollen cytoplasm that ranged in size from 30 nm to 4 μm and contained Bet v 1 allergens.

Conclusion When highly allergenic birch trees are flowering and exposed to moisture followed by drying winds they can produce particulate aerosols containing pollen allergens. These particles are small enough to deposit in the peripheral airways and have the potential to induce an inflammatory response.

A case of Kingella kingae endocarditis complicated by native mitral valve rupture

We report a case of Kingella kingae endocarditis in a patient with a history of recent respiratory tract infection and dental extraction. This case is remarkable for embolic and vasculitic phenomena in association with a large valve vegetation and valve perforation. Kingella kingae is an organism known to cause endocarditis, however early major complications are uncommon. Our case of Kingella endocarditis behaved in a virulent fashion necessitating a combined approach of intravenous antibiotic therapy and a valve replacement. It highlights the importance of expedited investigation for endocarditis in patients with Kingella bacteraemia.

Aortic intima-media thickness measured by trans-abdominal ultrasound as an early life marker of subclinical atherosclerosis

Atherosclerosis is a chronic inflammatory process that begins in early life. Improved identification of markers of early atherosclerosis via neonatal aortic intima-media thickness (aIMT) measurement may allow the development of interventions to prevent or reduce later cardiovascular disease.

Reproducibility of aortic intima-media thickness in infants using edge-detection software and manual caliper measurements

Background: Aortic intima-media thickness measured by transabdominal ultrasound (aIMT) is an intermediate phenotype of cardiovascular risk. We aimed to (1) investigate the reproducibility of aIMT in a population-derived cohort of infants; (2) establish the distribution of aIMT in early infancy; (3) compare measurement by edge-detection software to that by manual sonographic calipers; and (4) assess the effect of individual and environmental variables on image quality. Methods. Participants were term infants recruited to a population-derived birth cohort study. Transabdominal ultrasound was performed at six weeks of age by one of two trained operators. Thirty participants had ultrasounds performed by both operators on the same day. Data were collected on environmental (infant sleeping, presence of a sibling, use of sucrose, timing during study visit) and individual (post-conception age, weight, gender) variables. Two readers assessed image quality and measured aIMT by edge-detection software and a subset by manual sonographic calipers. Measurements were repeated by the same reader and between readers to obtain intra-observer and inter-observer reliability. Results: Aortic IMT was measured successfully using edge-detection in 814 infants, and 290 of these infants also had aIMT measured using manual sonographic calipers. The intra-reader intra-class correlation (ICC) (n = 20) was 0.90 (95% CI 0.76, 0.96), mean difference 1.5 μm (95% LOA -39, 59). The between reader ICC using edge-detection (n = 20) was 0.92 (95% CI 0.82, 0.97) mean difference 2 μm (95% LOA -45.0, 49.0) and with manual caliper measurement (n = 290) the ICC was 0.84 (95% CI 0.80, 0.87) mean difference 5 μm (95% LOA -51.8, 61.8). Edge-detection measurements were greater than those from manual sonographic calipers (mean aIMT 618 μm (50) versus mean aIMT 563 μm (49) respectively; p < 0.001, mean difference 44 μm, 95% LOA -54, 142). With the exception of infant crying (p = 0.001), no associations were observed between individual and environmental variables and image quality. Conclusion: In a population-derived cohort of term infants, aIMT measurement has a high level of intra and inter-reader reproducibility. Measurement of aIMT using edge-detection software gives higher inter-reader ICC than manual sonographic calipers. Image quality is not substantially affected by individual and environmental factors. © 2014 McCloskey et al.; licensee BioMed Central Ltd.

Blood pressure and cognitive function: the role of central aortic and brachial pressures

Central (aortic) blood pressures differ from brachial pressures and may be more relevant to the study of cognitive function, given that blood is delivered to the brain through the central large arteries. Pulse-pressure amplification reflects the augmentation of blood pressure between the central and peripheral arteries, which diminishes with aging. We aimed to determine the association between central blood pressure and cognitive function in independently living adults aged 20 to 82 years (N = 493). In adjusted regression models, higher central systolic pressure and higher central pulse pressure were each associated with poorer processing speed, Stroop processing, and recognition memory. Lower amplification was associated with poorer Stroop processing, working memory, and recognition memory. Higher brachial systolic pressure and brachial pulse pressure were both associated with poorer Stroop processing. In summary, central pressures and amplification were sensitive indicators of cognitive aging, predicting aspects of cognitive performance not predicted by brachial blood pressure.

Prognostic value of fat mass and skeletal muscle mass determined by computed tomography in patients who underwent transcatheter aortic valve implantation

Body composition (fat mass [FM] and skeletal muscle mass [SMM]) predicts clinical outcomes. In particular, loss of SMM (sarcopenia) is associated with frailty and mortality. There are no data on the prevalence and impact of FM and SMM in patients undergoing transcatheter aortic valve implantation (TAVI). The objective of this study is to determine body composition from pre-TAVI computed tomography (CT) and evaluate its association with clinical outcomes in patients who underwent TAVI. A total of 460 patients (mean age 81 ± 8 years, men: 51%) were included. Pre-TAVI CTs of the aorto-ilio-femoral axis were analyzed for FM and SMM cross-sectional area at the level of the third lumbar vertebrae (L3). Regression equations correlating cross-sectional area at L3 to total body FM and SMM were used to determine prevalence of sarcopenia, obesity, and sarcopenic obesity in patients (64%, 65%, and 46%, respectively). Most TAVI procedures were performed through a transfemoral approach (59%) using a balloon-expandable valve (94%). The 30-day and mid-term (median 12 months [interquartile range 6 to 27]) mortality rates were 6.1% and 29.6%, respectively. FM had no association with clinical outcomes, but sarcopenia predicted cumulative mortality (hazard ratio 1.55, 95% confidence interval 1.02 to 2.36, p = 0.04). In conclusion, body composition analysis from pre-TAVI CT is feasible. Sarcopenia, obesity, and sarcopenic obesity are prevalent in the TAVI population, with sarcopenia predictive of cumulative mortality.