IBD: Is measuring bone age in children with Crohn's disease useful?

The different distribution of enzymatic collagen cross-links found in adult and children bone result in different mechanical behavior of collagen

Enzymatic collagen cross-linking has been shown to play an important role in the macroscopic elastic and plastic deformation of bone across ages. However, its direct contribution to collagen fibril deformation is unknown. The aim of this study is to determine how covalent intermolecular connections from enzymatic collagen cross-links contribute to collagen fibril elastic and plastic deformation of adults and children's bone matrix. We used ex vivo data previously obtained from biochemical analysis of children and adults bone samples (n = 14; n = 8, respectively) to create 22 sample-specific computational models of cross-linked collagen fibrils. By simulating a tensile test for each fibril, we computed the modulus of elasticity (E), ultimate tensile and yield stress (σ_u and σ_y), and elastic, plastic and total work (W_e, W_p and W_tot) for each collagen fibril. We present a novel difference between children and adult bone in the deformation of the collagen phase and suggest a link between collagen fibril scale and macroscale for elastic behavior in children bone under the influence of immature enzymatic cross-links. We show a parametric linear correlation between W_e and immature enzymatic collagen cross-links at the collagen fibril scale in the children population that is similar to the one we found at the macroscale in our previous study. Finally, we suggest the key role of covalent intermolecular connections to stiffness parameters (e.g. elastic modulus and W_e) in children's collagen fibril and to toughness parameters in adult's collagen fibril, respectively.

Nondestructive estimation of growth year in ginseng cultivars using the means of mathematical modeling on the basis of allometry

Growth-year authentication has extraordinary significance for plant growth, structure and development research, and has a wide range of applications in value assessment of economic crops. Panax ginseng is the most commonly used medicinal plant in Asian countries. The fix number of growth-year is an important quality evaluation which is difficult to be obtained accurately in current technical conditions. Preliminary authentication theory for growth-year has been described in previous studies using a short-lived perennial medicinal plant (Paeonia lactiflora pall.) as the research material. In this research, we focused on the growth-year estimation in ginseng cultivars, and attempt to explore the age estimation method for vascular plants according to mathematical simulation of the root structure development. Micro data was obtained from 204 individuals of 3 different kinds of ginseng cultivars, which have a series of gradient age and a clear growth record. Outer diameter of the vascular cambium (b) and the radius of cross section (r) were measured with ordinary stereo microscope. We further designed and established two different kinds of authentication model based on the taproot structure development for growth year authentication (P =β*M-α and M = K*X1 (a) (1) X2 (a) (2) ). Moreover, the models were applied to identify the growth year of ginseng without damage using Micro-CT or DEI reconstruction. A potential method, have been recently described, the age of ginseng can be analyzed by telomere length and telomerase activity. However, we found that there are different results indicated in other species. We concluded that microscopic methods perceived currently were provided a more effective means for growth-year authentication.

Impaired growth and puberty in pediatric patients with inflammatory bowel disease: Etiology and treatment

Growth failure associated with delayed puberty is a unique feature in pediatric patients with inflammatory bowel disease (IBD), especially those with Crohn's disease, which has a negative effect on quality of life, emotional functioning, social functioning, and body image. Although the underlying mechanisms are not fully clear, the condition may be induced by the effects of malnutrition, inflammatory process and glucocorticoid on the growth hormone/insulin-like growth factor-1 axis or on the growth plate. Nutrition, biologic agents, intestinal resection and glucocorticoids are main treatments. Standards for monitoring and treatment of impaired growth and development in pediatric IBD patients need to be formulated. To achieve optimal growth, the efforts of hospitals, families and society are necessary.

In vitro ultrasonic and mechanic characterization of the modulus of elasticity of children cortical bone

The assessment of elastic properties in children's cortical bone is a major challenge for biomechanical engineering community, more widely for health care professionals. Even with classical clinical modalities such as X-ray tomography, MRI, and/or echography, inappropriate diagnosis can result from the lack of reference values for children bone. This study provides values for elastic properties of cortical bone in children using ultrasonic and mechanical measurements, and compares them with adult values. 18 fibula samples from 8 children (5-16 years old, mean age 10.6 years old ±4.4) were compared to 16 fibula samples from 3 elderly adults (more than 65 years old). First, the dynamic modulus of elasticity (Edyn) and Poisson's ratio (ν) are evaluated via an ultrasonic method. Second, the static modulus of elasticity (Esta) is estimated from a 3-point microbending test. The mean values of longitudinal and transverse wave velocities measured at 10 MHz for the children's samples are respectively 3.2mm/μs (±0.5) and 1.8mm/μs (±0.1); for the elderly adults' samples, velocities are respectively 3.5mm/μs (±0.2) and 1.9 mm/μs (±0.09). The mean Edyn and the mean Esta for the children's samples are respectively 15.5 GPa (±3.4) and 9.1 GPa (±3.5); for the elderly adults' samples, they are respectively 16.7 GPa (±1.9) and 5.8 GPa (±2.1). Edyn, ν and Esta are in the same range for children's and elderly adults' bone without any parametric statistical difference; a ranking correlation between Edyn and Esta is shown for the first time.