THREE DIMENSIONAL RECONSTRUCTION OF THE COMPONENTS OF THE CAROTID PLAQUE FROM STANDARD CT MEDICAL IMAGES

ABSTRACT The present study compares plaque and calcium volumes between sixteen diseased human carotid arteries. Half were from symptomatic patients, and half were from asymptomatic patients. In-house software was developed for the 3-D reconstruction of the plaque components from computerized tomography (CT) images. Results revealed higher mean total volume (TV) in the symptomatic group compared to the asymptomatic group. In contrast, the mean ratio of calcium volume (CV) to TV was lower for the symptomatic group compared to the asymptomatic group. This shows that symptomatic patients have a significantly greater plaque burden with minimal plaque calcification. The process of acquiring the data helped understand what tools/features are needed to conduct this work. One important feature of this software is the ability to create automated regions of interest (ROI) in addition to simple manual selection/modification of the ROIs in a GUI environment

An \u3cem\u3eFTO\u3c/em\u3e Gene Variant Moderates the Association between Parental Restriction and Child BMI

Objective: This study aimed to explore whether a common variant in the FTO gene moderates the relationship between parental restriction and child BMI. Methods: This study reports on baseline data from 178 parent-child (ages 9–10 years) dyads. Parents completed the Child Feeding Questionnaire and reported on socio-demographic characteristics. Each child’s height, weight and FTO rs9939609 genotype was assessed. Ordinary least squares regression was used to fit the child’s BMI-percentile on parental restriction and the child’s FTO genotype, adjusted for covariates. A likelihood ratio test was used to compare a model with and without a multiplicative interaction term between restriction and genotype. Results: Most participants (93.3%) were white, non-Hispanic. Twenty-three percent of children were overweight/obese and FTO genotype was associated with weight status. Mean parental restriction was statistically higher among overweight/obese vs. normal weight children: 3.3 (SD 0.8) vs. 2.8 (SD 1.0); t-test p-value = 0.002. Parental restriction was positively associated with child BMI-percentile and BMI-z only among children with two copies of the high-risk FTO allele (p for interaction = 0.02), where each one-point increase in parental restriction was associated with a 14.7 increase in the child’s BMI-percentile or a 0.56-point increase in the child’s BMI z-score. Conclusion: For only the children with two high-risk alleles, parental restriction was positively associated with child BMI-percentile

Evaluating the Effects of Cerebrospinal Fluid Protein Content on the Performance of Differential Pressure Valves and Antisiphon Devices Using a Novel Benchtop Shunting Model

BACKGROUNDHydrocephalus is managed by surgically implanting flow-diversion technologies such as differential pressure valves and antisiphoning devices; however, such hardware is prone to failure. Extensive research has tested them in flow-controlled settings using saline or de-aerated water, yet little has been done to validate their performance in a setting recreating physiologically relevant parameters, including intracranial pressures, cerebrospinal fluid (CSF) protein content, and body position.OBJECTIVETo more accurately chart the episodic drainage characteristics of flow-diversion technology. A gravity-driven benchtop model of flow was designed and tested continuously during weeks-long trials.METHODSUsing a hydrostatic pressure gradient as the sole driving force, interval flow rates of 6 valves were examined in parallel with various fluids. Daily trials in the upright and supine positions were run with fluid output collected from distal catheters placed at alternating heights for extended intervals.RESULTSSignificant variability in flow rates was observed, both within specific individual valves across different trials and among multiple valves of the same type. These intervalve and intravalve variabilities were greatest during supine trials and with increased protein. None of the valves showed evidence of overt obstruction during 30 d of exposure to CSF containing 5 g/L protein.CONCLUSIONDay-to-day variability of ball-in-cone differential pressure shunt valves may increase overdrainage risk. Narrow-lumen high-resistance flow control devices as tested here under similar conditions appear to achieve more consistent flow rates, suggesting their use may be advantageous, and did not demonstrate any blockage or trend of decreasing flow over the 3 wk of chronic use

Can it be harmful for parents to talk to their child about their weight? A meta-analysis

Many parents express concern that raising the issue of weight risks harming their child's physical self-perceptions and wellbeing. Such concerns can deter families from engaging with weight management services. This systematic review aimed to investigate the evidence behind these concerns by analysing the association between parent-child weight-talk and child wellbeing. A systematic search of eight databases identified four intervention studies and 38 associative studies. Meta-analysis was only possible for the associative studies; to facilitate more meaningful comparisons, weight-talk was categorized into four communication types and effect size estimates for the association between these and wellbeing indicators were calculated through a random effects model. Encouraging children to lose weight and criticizing weight were associated with poorer physical self-perceptions and greater dieting and dysfunctional eating (effect sizes: 0.20 to 0.47). Conversely, parental encouragement of healthy lifestyles without explicit reference to weight was associated with better wellbeing, but this was only measured in two studies. Of the four intervention studies, only one isolated the effects of parents' communication on wellbeing outcomes, reporting a positive effect. There was no effect of age on the strength of associations, but dysfunctional eating was more strongly associated with parent communication for girls than boys. The findings indicate that some forms of parent-child weight-talk are associated with poor wellbeing, but suggest that this is not inevitable. Encouraging healthy behaviours without reference to weight-control, and positive parental involvement in acknowledging and addressing weight-concern may avoid such outcomes. More longitudinal research is needed to analyse the direction of these effects

Velocity and wall shear measurements inside a vascular graft model under steady and pulsatile flow conditions

Ph.D.Don P. Gidden

The Influence of Coughing on Cerebrospinal Fluid Pressure in an in Vitro Syringomyelia Model with Spinal Canal Stenosis

Five in vitro models were constructed which were representative of various pathologies of the spinal canal (SC) associated with syringomyelia (SM). The models were subjected to a cough type flow impulse while monitoring the pressure environment in the syrinx and subarachnoid space (SAS) regions of the model. The results indicated that conditions can arise during a cough which would provide pressure forces to encourage cerebrospinal fluid (CSF) movement into the syrinx cavity

The influence of coughing on cerebrospinal fluid pressure in an <it>in vitro </it>syringomyelia model with spinal subarachnoid space stenosis

Abstract Background The influence of coughing, on the biomechanical environment in the spinal subarachnoid space (SAS) in the presence of a cerebrospinal fluid flow stenosis, is thought to be an important etiological factor in craniospinal disorders, including syringomyelia (SM), Chiari I malformation, and hydrocephalus. The aim of this study was to investigate SAS and syrinx pressures during simulated coughing using in vitro models and to provide information for the understanding of the craniospinal fluid system dynamics to help develop better computational models. Methods Four in vitro models were constructed to be simplified representations of: 1) non-communicating SM with spinal SAS stenosis; 2) non-communicating SM due to spinal SAS stenosis with a distensible spinal column; 3) non-communicating SM post surgical removal of a spinal SAS stenosis; and 4) a spinal SAS stenosis due to spinal trauma. All of the models had a flexible spinal cord. To simulate coughing conditions, an abrupt CSF pressure pulse (~ 5 ms) was imposed at the caudal end of the spinal SAS by a computer-controlled pump. Pressure measurements were obtained at 4 cm intervals along the spinal SAS and syrinx using catheter tip transducers. Results Pressure measurements during a simulated cough, showed that removal of the stenosis was a key factor in reducing pressure gradients in the spinal SAS. The presence of a stenosis resulted in a caudocranial pressure drop in the SAS, whereas pressure within the syrinx cavity varied little caudocranially. A stenosis in the SAS caused the syrinx to balloon outward at the rostral end and be compressed at the caudal end. A >90% SAS stenosis did not result in a significant Venturi effect. Increasing compliance of the spinal column reduced forces acting on the spinal cord. The presence of a syrinx in the cord when there was a stenosis in the SAS, reduced pressure forces in the SAS. Longitudinal pressure dissociation acted to suck fluid and tissue caudocranially in the SAS with a stenosis. Conclusions Pressures in the spinal SAS during a simulated cough in vitro had similar peak, transmural, and longitudinal pressures to in vivo measurements reported in the literature. The pressure wave velocities and pressure gradients during coughing (longitudinal pressure dissociation and transmural pressure) were impacted by alterations in geometry, compliance, and the presence of a syrinx and/or stenosis.</p