Evaluation of the Trabecular Structure of Mandibular Condyles in Children Using Fractal Analysis

Objective: To evaluate the trabecular internal structure of the mandibular condyle with fractal analysis on panoramic radiography in children. Study Design: 159 panoramic radiographs were separated into 8 groups according to age and gender. The radiographs were standardized as 8-bit images. Regions of interest, located on both mandibular condyles, were selected as 64x64 pixel squares. Image J v1.50i software was used to obtain the fractal dimension (FD) values by the box-counting method. Results: The data obtained from the right and left condyles were analyzed in terms of gender and age groups. No statistically significant difference was observed between the genders in respect of the mean FD values for both condyles (p>0.05). Mean, standard deviations and the 95% confidence intervals for the FD values of the left and right condyles were obtained according to age. A statistically significant difference was observed in the mean FD values for both left (p= 0.019) and right (p= 0.000) condyles when all groups were compared and no statistically significant difference was found between all groups except the 6-year-old group for both condyles. In both condyles, the significantly lowest mean FD values were determined in the 6 years age group. Conclusions: The FD values of the mandibular condyle trabecular structure changed with age. It will be possible to evaluate these changes from panoramic radiographs by making calculations using the fractal analysis method.

Growth and development of trabecular structure in the calcaneus of Japanese macaques (Macaca fuscata) reflects locomotor behavior, life-history, and neuromuscular development.

We aim to broaden the analysis of bone structure by suggesting a new way to incorporate the interactions between behavior, neuromuscular development, and life-history. We examine the associations between these variables and age-related variation in trabecular structure in the calcaneus of Japanese macaques (Macaca fuscata). If skeletal markers linking these variables can be established, our inferences of the biology and behavior of fossil species would be significantly improved. We μCT scanned the calcaneus in a cross-sectional sample of 36 juveniles aged between 0 and 7 years old and 5 adults at the Primate Research Institute, Japan. We calculated whole bone averages of standard trabecular properties and generated whole-bone morphometric maps of bone volume fraction and Youngs modulus. Trabecular structure is increasingly heterogeneous in older individuals. BV/TV decreases during the first month of life and increases afterwards, coinciding with the onset of independent locomotion. At birth, primary Youngs modulus is oriented orthogonal to the ossification center, but after locomotor onset bone structure becomes stiffest in the direction of joint surfaces and muscle attachments. Age-related variation in bone volume fraction is best predicted by an interaction between neuromaturation, body mass, and locomotor independence. Results support the common assumption that trabecular structure dynamically adapts to novel joint loading conditions during ontogeny. The timing of independent locomotion, body size, and neuromuscular development, are all correlated to age-related variation in the trabecular structure of the macaque calcaneus. The causal mechanisms behind the observed patterns cannot be directly inferred from our cross-sectional study. If the model presented in this paper holds up under longitudinal experimental conditions, trabecular structure can be used both to infer behavior from fossil morphology and to serve as a valuable proxy for neuromuscular maturation and life history events like locomotor onset and the achievement of an adult-like gait.

RAP1GAP is a novel marker of trabecular pattern and poor sorafenib treatment response in hepatocellular carcinoma

Background The trabecular pattern is one of the most common features of hepatocellular carcinoma (HCC). In this study, we aimed to identify the molecular mechanisms underlying different trabecular patterns in HCC, and their interaction with current therapies. Methods To screen potential biomarkers of different trabecular patterns, we first linked gene expression data to haematoxylin and eosin (H&E) images from The Cancer Genome Atlas (TCGA). The Gene Expression Omnibus (GEO) database was used to explore potential targets of sorafenib treatment. Selected candidate biomarkers were further verified by immunohistochemistry, and their relationship with sorafenib efficacy was evaluated in 107 HCC samples with trabecular patterns. Results Analysis of RNA sequencing data from TCGA showed that the increasing number of cells in the trabecular structure correlated with increase in the expression of related signalling pathways—Ras, Rap1, IL17, TNF, AGE-RAGE, oestrogen, toll-like receptor signalling, and ubiquitin-mediated proteolysis—and genes related to response to oxygen levels and neoangiogenesis. In contrast, the expression of bile acid and carton, tryptophan, butanoate, and lipid metabolism-related pathways was reduced. The GEO database showed that RAP1GAP, TOB1, ACO2, and SCNN1D expression levels were selectively up-regulated in sorafenib non-responders. Based on the combined analysis of the two datasets and our previous studies, two candidate biomarkers, RAP1GAP and HIF1α, were selected. Immunohistochemical staining showed that RAP1GAP and HIF1α were expressed in the tumour tissues. Interestingly, RAP1GAP was also expressed in the tumour sinusoids. Overexpression of RAP1GAP in sinusoids were associated with trabecular patterns. Multivariate analysis also showed that RAP1GAP expression in the sinusoid was an independent predictor of progressive free survival (PFS) and overall survival (OS) in response to sorafenib treatment. Conclusions RAP1GAP is an essential microenvironment marker in the trabecular structure of HCC and exhibits an adverse association with outcome in sorafenib treatment.