The existence of an insulin-stimulated glucose and non-essential but not essential amino acid substrate interaction in diabetic pigs

<p>Abstract</p> <p>Background</p> <p>The generation of energy from glucose is impaired in diabetes and can be compensated by other substrates like fatty acids (Randle cycle). Little information is available on amino acids (AA) as alternative energy-source in diabetes. To study the interaction between insulin-stimulated glucose and AA utilization in normal and diabetic subjects, intraportal hyperinsulinaemic euglycaemic euaminoacidaemic clamp studies were performed in normal (n = 8) and streptozotocin (120 mg/kg) induced diabetic (n = 7) pigs of ~40-45 kg.</p> <p>Results</p> <p>Diabetic vs normal pigs showed basal hyperglycaemia (19.0 ± 2.0 vs 4.7 ± 0.1 mmol/L, <it>P </it>< .001) and at the level of individual AA, basal concentrations of valine and histidine were increased (<it>P </it>< .05) whereas tyrosine, alanine, asparagine, glutamine, glutamate, glycine and serine were decreased (<it>P </it>< .05). During the clamp, diabetic vs normal pigs showed reduced insulin-stimulated glucose clearance (4.4 ± 1.6 vs 16.0 ± 3.0 mL/kg·min, <it>P </it>< .001) but increased AA clearance (166 ± 22 vs 110 ± 13 mL/kg· min, <it>P </it>< .05) at matched arterial euglycaemia (5-7 mmol/L) and euaminoacidaemia (2.8-3.5 mmol/L). The increase in AA clearance was mainly caused by an increase in non-essential AA clearance (93.6 ± 13.8 vs 46.6 ± 5.4 mL/kg·min, <it>P </it>< .01), in particular alanine (14.2 ± 2.4 vs 3.2 ± 0.4 mL/kg·min, <it>P </it>< .001)<b/>. Essential AA clearance was largely unchanged (72.9 ± 8.5 vs 63.3 ± 8.5 mL/kg· min), however clearances of threonine (<it>P </it>< .05) and tyrosine (<it>P </it>< .01) were increased in diabetic vs normal pigs (8.1 ± 1.3 vs 5.2 ± 0.5, and 14.3 ± 2.5 vs 6.4 ± 0.7 mL/kg· min, respectively).</p> <p>Conclusions</p> <p>The ratio of insulin-stimulated glucose versus AA clearance was decreased 5.4-fold in diabetic pigs, which was caused by a 3.6-fold decrease in glucose clearance and a 2.0-fold increase in non-essential AA clearance. In parallel with the Randle concept (glucose - fatty acid cycle), the present data suggest the existence of a glucose and non-essential AA substrate interaction in diabetic pigs whereby reduced insulin-stimulated glucose clearance seems to be partly compensated by an increase in non-essential AA clearance whereas essential AA are preferentially spared from an increase in clearance.</p

Sexual maturation in relation to polychlorinated aromatic hydrocarbons: Sharpe and Skakkebaek's hypothesis revisited.

Polychlorinated aromatic hydrocarbons (PCAHs) have been described as endocrine disruptors in animals and in accidentally or occupationally exposed humans. In the present study we examined the effect of moderate exposure to PCAHs on sexual maturation. Two hundred adolescents (mean age, 17.4 years) who resided in two polluted suburbs and a rural control area in Flanders (Belgium) participated. We measured the serum concentration of polychlorinated biphenyl (PCB) congeners 138, 153, and 180 and dioxin-like compounds [chemically activated luciferase expression (CALUX) assay] as biomarkers of exposure. School physicians assessed the pubertal development of boys and girls and measured testicular volume. In one suburb near two waste incinerators, compared with the other suburb and the control area, fewer boys (p < 0.001) had reached the adult stages of genital development (62% vs. 92% and 100%, respectively) and pubic hair growth (48% vs. 77% and 100%). Also, in the same suburb, fewer girls (p = 0.04) had reached the adult stage of breast development (67% vs. 90% and 79%). In individual boys, a doubling of the serum concentration of PCB congener 138 increased the odds of not having matured into the adult stage of genital development by 3.5 (p = 0.04); similarly for PCB congener 153 in relation to male pubic hair growth, the odds ratio was 3.5 (p = 0.04). In girls, a doubling of the serum dioxin concentration increased the odds of not having reached the adult stage of breast development by 2.3 (p = 0.02). Left plus right testicular volume was lower in both polluted areas than in the control area (42.4 mL vs. 47.3 mL, p = 0.005) but was not related to the current exposure of the adolescents to PCAHs. Through endocrine disruption, environmental exposure to PCAHs may interfere with sexual maturation and in the long-run adversely affect human reproduction

Computer-based estimation of the hip joint reaction force and hip flexion angle in three different sitting configurations

Sitting is part of our daily work and leisure activities and can be performed in different configurations. To date, the impact of different sitting configurations on hip joint loading has not been studied. We therefore evaluated the hip joint reaction force (HJRF) and hip flexion angle in a virtual representative male Caucasian population by means of musculoskeletal modelling of three distinct sitting configurations: a simple chair, a car seat and a kneeling chair configuration. The observed median HJRF in relation to body weight and hip flexion angle, respectively, was 22.3% body weight (%BW) and 63° for the simple chair, 22.5%BW and 79° for the car seat and 8.7%BW and 50° for the kneeling chair. Even though the absolute values of HJRF are low compared to the forces generated during dynamic activities, a relative reduction of over 50% in HJRF was observed in the kneeling chair configuration. Second, the hip flexion angles were both in the kneeling chair (-29°) and simple chair configuration (-16°) lower compared to the car seat and, as such, did not reach the threshold value for femoroacetabular conflict. In conclusion, the kneeling chair appears to hold the greatest potential as an ergonomic sitting configuration for the hip joint.Van Houcke J., Schouten A., Steenackers G., Vandermeulen D., Pattyn C., Audenaert E.A., ''Computer-based estimation of the hip joint reaction force and hip flexion angle in three different sitting configurations'', Applied ergonomics, vol. 63, pp. 99-105, September 2017.status: publishe

Automatic detection of myocardial infarction through a global shape feature based on local statistical modeling

© Springer International Publishing Switzerland 2016. This paper presents a local-to-global statistical approach for modeling the major components of left ventricular (LV) shape using its 3-D landmark representation. The rationale for dividing the LV into local areas is bi-fold: (1) to better identify abnormalities that lead to local shape remodeling and, (2) to decrease the number of shape variables by using a limited set of landmark points for an efficient statistical parametrization. Principal Component Analysis (PCA) is used for the statistical modeling of the local regions and subsets of the learned parameters that provide significant discriminatory information are taken from each local model in a feature selection stage. The selected local parameters are then concatenated to form a global representation of the LV and to train a classifier for differentiating between normal and infarcted LV shapes.Tabassian M., Alessandrini M., Claes P., De Marchi L., Vandermeulen D., Masetti G., D'hooge J., ''Automatic detection of myocardial infarction through a global shape feature based on local statistical modeling'', Proceedings 6th international workshop on statistical atlases and computational models of the heart: imaging and modelling challenges - STACOM’15, held in conjunction with MICCAI 2015, 9 pp., October 9, 2015, Munich, Germany.status: publishe

Cascaded statistical shape model based segmentation of the full lower limb in CT

Image segmentation has become an important tool in orthopedic and biomechanical research. However, it greatly remains a time-consuming and laborious task. In this manuscript, we propose a fully automatic model-based segmentation pipeline for the full lower limb in computed tomography (CT) images. The method relies on prior shape model fitting, followed by a gradient-defined free from deformation. The technique allows for the generation of anatomically corresponding surface meshes, which can subsequently be applied in anatomical and mechanical simulation studies. Starting from an initial, small (n <= 10) sample of manual segmentations, the model is continuously updated and refined with newly segmented training samples. Validation of the segmentation pipeline was performed by comparing the automatic segmentations against corresponding manual segmentations. Convergence of the segmentation pipeline was obtained in 250 cases and failed in three samples. The average distance error ranged from 0.53 to 0.76 mm and maximal error ranged from 2.0 to 7.8 mm for the 7 different osteological structures that were investigated. The accuracy of the shape model-based segmentation gradually increased as the number of training shapes in the updated population also increased. When optimized with the free form deformation, however, average segmentation accuracy rapidly plateaued from already as little as 20 training samples on. The maximum segmentation error plateaued from 100 training samples on

The New Highwind Carousel for Outdoor Rotational Start Experiments

status: accepte