Open reading frame dominance indicates protein-coding potential of RNAs.

Recent studies have identified numerous RNAs with both coding and noncoding functions. However, the sequence characteristics that determine this bifunctionality remain largely unknown. In the present study, we develop and test the open reading frame (ORF) dominance score, which we define as the fraction of the longest ORF in the sum of all putative ORF lengths. This score correlates with translation efficiency in coding transcripts and with translation of noncoding RNAs. In bacteria and archaea, coding and noncoding transcripts have narrow distributions of high and low ORF dominance, respectively, whereas those of eukaryotes show relatively broader ORF dominance distributions, with considerable overlap between coding and noncoding transcripts. The extent of overlap positively and negatively correlates with the mutation rate of genomes and the effective population size of species, respectively. Tissue-specific transcripts show higher ORF dominance than ubiquitously expressed transcripts, and the majority of tissue-specific transcripts are expressed in mature testes. These data suggest that the decrease in population size and the emergence of testes in eukaryotic organisms allowed for the evolution of potentially bifunctional RNAs.

Prognostic biomarker study in patients with clinical stage I esophageal squamous cell carcinoma: JCOG0502-A1.

We undertook genomic analyses of Japanese patients with stage I esophageal squamous cell carcinoma (ESCC) to investigate the frequency of genomic alterations and the association with survival outcomes. Biomarker analysis was carried out for patients with clinical stage T1bN0M0 ESCC enrolled in JCOG0502 (UMIN000000551). Whole-exome sequencing (WES) was performed using DNA extracted from formalin-fixed, paraffin-embedded tissue of ESCC and normal tissue or blood sample. Single nucleotide variants (SNVs), insertions/deletions (indels), and copy number alterations (CNAs) were identified. We then evaluated the associations between each gene alteration with a frequency of 10% or more and progression-free survival (PFS) using a Cox regression model. We controlled for family-wise errors at 0.05 using the Bonferroni method. Among the 379 patients who were enrolled in JCOG0502, 127 patients were successfully analyzed using WES. The median patient age was 63 years (interquartile range, 57-67 years), and 78.0% of the patients ultimately underwent surgery. The 3-year PFS probability was 76.3%. We detected 20 genes with SNVs, indels, or amplifications with a frequency of 10% or more. Genomic alterations in FGF19 showed the strongest association with PFS with a borderline level of statistical significance of P = .00252 (Bonferroni-adjusted significance level is .0025). Genomic alterations in FGF4, MYEOV, CTTN, and ORAOV1 showed a marginal association with PFS (P < .05). These genomic alterations were all CNAs at chromosome 11q13.3. We have identified new genomic alterations associated with the poor efficacy of ESCC (T1bN0M0). These findings open avenues for the development of new potential treatments for patients with ESCC.

Single-cell DNA and RNA sequencing reveals the dynamics of intra-tumor heterogeneity in a colorectal cancer model.

BACKGROUND: Intra-tumor heterogeneity (ITH) encompasses cellular differences in tumors and is related to clinical outcomes such as drug resistance. However, little is known about the dynamics of ITH, owing to the lack of time-series analysis at the single-cell level. Mouse models that recapitulate cancer development are useful for controlled serial time sampling. RESULTS: We performed single-cell exome and transcriptome sequencing of 200 cells to investigate how ITH is generated in a mouse colorectal cancer model. In the model, a single normal intestinal cell is grown into organoids that mimic the intestinal crypt structure. Upon RNAi-mediated downregulation of a tumor suppressor gene APC, the transduced organoids were serially transplanted into mice to allow exposure to in vivo microenvironments, which play relevant roles in cancer development. The ITH of the transcriptome increased after the transplantation, while that of the exome decreased. Mutations generated during organoid culture did not greatly change at the bulk-cell level upon the transplantation. The RNA ITH increase was due to the emergence of new transcriptional subpopulations. In contrast to the initial cells expressing mesenchymal-marker genes, new subpopulations repressed these genes after the transplantation. Analyses of colorectal cancer data from The Cancer Genome Atlas revealed a high proportion of metastatic cases in human subjects with expression patterns similar to the new cell subpopulations in mouse. These results suggest that the birth of transcriptional subpopulations may be a key for adaptation to drastic micro-environmental changes when cancer cells have sufficient genetic alterations at later tumor stages. CONCLUSIONS: This study revealed an evolutionary dynamics of single-cell RNA and DNA heterogeneity in tumor progression, giving insights into the mesenchymal-epithelial transformation of tumor cells at metastasis in colorectal cancer.

Cohesin complex-associated holoprosencephaly.

Marked by incomplete division of the embryonic forebrain, holoprosencephaly is one of the most common human developmental disorders. Despite decades of phenotype-driven research, 80-90% of aneuploidy-negative holoprosencephaly individuals with a probable genetic aetiology do not have a genetic diagnosis. Here we report holoprosencephaly associated with variants in the two X-linked cohesin complex genes, STAG2 and SMC1A, with loss-of-function variants in 10 individuals and a missense variant in one. Additionally, we report four individuals with variants in the cohesin complex genes that are not X-linked, SMC3 and RAD21. Using whole mount in situ hybridization, we show that STAG2 and SMC1A are expressed in the prosencephalic neural folds during primary neurulation in the mouse, consistent with forebrain morphogenesis and holoprosencephaly pathogenesis. Finally, we found that shRNA knockdown of STAG2 and SMC1A causes aberrant expression of HPE-associated genes ZIC2, GLI2, SMAD3 and FGFR1 in human neural stem cells. These findings show the cohesin complex as an important regulator of median forebrain development and X-linked inheritance patterns in holoprosencephaly.

Comprehensive analysis of DNA adducts (DNA adductome analysis) in the liver of rats treated with 1,4-dioxane.

1,4-Dioxane is a genotoxic carcinogen, and its mutagenic properties were recently observed in the liver of guanine phosphoribosyl transferase (gpt) delta transgenic rats. However, the mechanisms of its genotoxicity remain unclear. We analyzed DNA adduct formation in rat livers following 1,4-dioxane treatment. After administering 1,4-dioxane in drinking water at doses of 0, 20, 200, and 5,000 ppm, liver adduct formation was analyzed by DNA adductome analysis. Adducts in treated rat livers were dose-dependently increased compared with those in the control group. Principal component analysis-discriminant analysis (PCA-DA) clearly revealed two clusters of DNA adducts, associated with 0 ppm and low-dose (20 ppm) 1,4-dioxane-treatment versus middle- and high-dose (200, 5,000 ppm)-treated rats. After confirming the intensity of each adduct, three adducts were screened as characteristic of 1,4-dioxane treatment. Two of the three candidates contained thymine or cytidine/uracil moieties. Another candidate was identified as 8-oxo-dG based on mass fragmentation together with high-resolution accurate-mass (HRAM) mass spectrometry data. Oxidative stress responses may partly explain the mechanisms of increased mutations in the liver of gpt delta rats following 1,4-dioxane treatment.

Feasibility and utility of a panel testing for 114 cancer-associated genes in a clinical setting: A hospital-based study.

Next-generation sequencing (NGS) of tumor tissue (ie, clinical sequencing) can guide clinical management by providing information about actionable gene aberrations that have diagnostic and therapeutic significance. Here, we undertook a hospital-based prospective study (TOP-GEAR project, 2nd stage) to investigate the feasibility and utility of NGS-based analysis of 114 cancer-associated genes (the NCC Oncopanel test). We examined 230 cases (comprising more than 30 tumor types) of advanced solid tumors, all of which were matched with nontumor samples. Gene profiling data were obtained for 187 cases (81.3%), 111 (59.4%) of which harbored actionable gene aberrations according to the Clinical Practice Guidelines for Next Generation Sequencing in Cancer Diagnosis and Treatment (Edition 1.0) issued by 3 major Japanese cancer-related societies. Twenty-five (13.3%) cases have since received molecular-targeted therapy according to their gene aberrations. These results indicate the utility of tumor-profiling multiplex gene panel testing in a clinical setting in Japan. This study is registered with UMIN Clinical Trials Registry (UMIN 000011141).

DNA Adductome Analysis Identifies N-Nitrosopiperidine Involved in the Etiology of Esophageal Cancer in Cixian, China.

Esophageal cancer is prevalent in Cixian, China, but the etiology of this disease remains largely unknown. Therefore, we explored this by conducting a DNA adductome analysis. Both tumorous and nontumorous tissues were collected from patients who underwent surgical procedures at Cixian Cancer Hospital and the Fourth Hospital of Hebei Medical University, which is in a low-incidence area. N2-(3,4,5,6-Tetrahydro-2H-pyran-2-yl)deoxyguanosine (THP-dG) was the major adduct detected in samples from esophageal cancer patients in Cixian. The precursor of THP-dG, N-nitrosopiperidine (NPIP), exhibited a strong mutagenic activity under metabolic activation in the Ames test and a significant dose-dependent increase in mutation frequency during an in vivo mutagenicity test with guanine phosphoribosyltransferase (gpt) delta rats. The NPIP-induced mutation was dominated by A:T to C:G transversions, followed by G:C to A:T and A:T to G:C transitions, in the liver and esophagus of animal samples. A similar mutational pattern was observed in the mutational signature of esophageal cancer patients that demonstrated weak correlation with THP-dG levels. These findings suggested that NPIP exposure is partly involved in the development of esophageal cancer in Cixian residents.

Remobilization causes site-specific cyst formation in immobilization-induced knee cartilage degeneration in an immobilized rat model.

An understanding of the articular cartilage degenerative process is necessary for the prevention and treatment of joint disease. The present study aimed to examine how long-term immobilization-induced cartilage degeneration is aggravated by remobilization. Sixty 8-week-old male Wistar rats were used in this study. The unilateral knee joint was immobilized using an external fixator for 8 weeks. The rats were killed at 0 and 3 days, and at 1, 2, 4 and 8 weeks after removing the fixator. After the rats were killed, the maximum knee extension angles were measured. Histological sections at the medial mid-condylar region (non-contact, transitional and contact regions of the femur and tibia) were prepared and scored. The cartilage thickness and number of chondrocytes were measured, and CD44 and Col2-3/4c expression levels were assessed immunohistochemically. The histological assessment revealed progressive aggravation of cartilage degeneration in the transitional region, with a decreased number of chondrocytes and CD44-positive chondrocytes as well as poor scoring over time, particularly in the tibia. Cyst formation was confirmed in the transitional region of the tibia at 8 weeks post-remobilization. The cartilage thickness in the transitional region was thicker than that in the contact region, particularly in the tibia. Col2-3/4c expression was observed in the non-contact and transitional regions, and the knee extension angle was recovered. In conclusion, immobilization-induced cartilage degeneration was aggravated by remobilization over time in the transitional region, followed by observations of a decreased number of chondrocytes and morphological disparity between different cartilage regions.

Alteration of cartilage surface collagen fibers differs locally after immobilization of knee joints in rats.

The purpose of this study was to examine the ultrastructural changes of surface cartilage collagen fibers, which differ by region and the length of the experimental period in an immobilization model of rat. Male Wistar rats were randomly divided into histological or macroscopic and ultrastructural assessment groups. The left knees of all the animals were surgically immobilized by external fixation for 1, 2, 4, 8 or 16 weeks (n = 5/time point). Sagittal histological sections of the medial mid-condylar region of the knee were obtained and assessed in four specific regions (contact and peripheral regions of the femur and tibia) and two zones (superficial and deep). To semi-quantify the staining intensity of the collagen fibers in the cartilage, picrosirius red staining was used. The cartilage surface changes of all the assessed regions were investigated by scanning electron microscopy (SEM). From histological and SEM observations, the fibrillation and irregular changes of the cartilage surface were more severe in the peripheral region than in the contact region. Interestingly, at 16 weeks post-immobilization, we observed non-fibrous structures at both the contact and peripheral regions. The collagen fiber staining intensity decreased in the contact region compared with the peripheral region. In conclusion, the alteration of surface collagen fiber ultrastructure and collagen staining intensity differed by the specific cartilage regions after immobilization. These results demonstrate that the progressive degeneration of cartilage is region specific, and depends on the length of the immobilization period.

Effect of microfabricated microgroove-surface devices on the morphology of mesenchymal stem cells.

The surface of a material that is in contact with cells is known to affect cell morphology and function. To develop an appropriate surface for tendon engineering, we used zigzag microgroove surfaces, which are similar to the tenocyte microenvironment. The purpose of this study was to investigate the effect of microgroove surfaces with different ridge angles (RAs), ridge lengths (RLs), ridge widths (RWs), and groove widths (GWs) on human bone marrow-derived mesenchymal stem cell (MSC) shape. Dishes with microgroove surfaces were fabricated using cyclic olefin polymer by injection-compression molding. The other parameters were fixed, and effects of different RAs (180 - 30 °), RLs (5 - 500 µm), RWs (5 - 500 µm), and GWs (5 - 500 µm) were examined. Changes in the zigzag shape of the cell due to different RAs, RLs, RWs, and GWs were observed by optical microscopy and scanning electron microscopy. Cytoskeletal changes were investigated using Phalloidin immunofluorescence staining. As observed by optical microscopy, MSCs changed to a zigzag shape in response to microgroove surfaces with different ridge and groove properties. . As observed by scanning electron microscopy, the cell shape changed at turns in the microgroove surface. Phalloidin immunofluorescence staining indicated that F-actin, not only in cell filopodia but also inside the cell body, changed orientation to conform to the microgrooves. In conclusion, the use of zigzag microgroove surfaces microfabricated by injection-compression molding demonstrated the property of MSCs to alter their shapes to fit the surface.

Evaluation of reference genes for human chondrocytes cultured in several different thermal environments.

PURPOSE: The purpose of this study was to identify reference genes showing stable expression in chondrocytes cultured under several different thermal environments and in different culture systems. MATERIALS AND METHODS: Human articular chondrocytes were cultured by monolayer or pellet culture system at 32 °C, 37 °C, and 41 °C for 3 days. Thereafter, the total RNA was extracted, and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was performed. The qRT-PCR data was analysed using three different algorithms (geNorm, NormFinder, and BestKeeper) to identify reference genes exhibiting stable expression from among the seven candidate reference genes (B2M, ACTB, GAPDH, HSPCB, RPL13a, YWHAZ, and 18S). RESULTS: The candidate reference genes, except for HSPCB and YWHAZ, showed systematic variations in expression. In the monolayer culture, RPL13a was the most stable gene identified using NormFinder and BestKeeper; on using geNorm, ACTB and GAPDH showed the highest expression stability. In the pellet culture, ACTB was the most stable gene identified using NormFinder and BestKeeper, whereas GAPDH and RPL13a were the most stable reference genes as determined using geNorm. In the combined group, B2M and GAPDH were the most stable genes identified using geNorm, whereas RPL13a and YWHAZ were the most stable as per NormFinder and BestKeeper, respectively. The best combination of two candidate reference genes among all the groups determined using NormFinder was RPL13a and YWHAZ. CONCLUSION: The combination of RPL13a and YWHAZ might be suitable as reference genes for human chondrocytes cultured at 32 °C, 37 °C, and 41 °C in monolayer, pellet, or combined cultures.

Optimum temperature for extracellular matrix production by articular chondrocytes.

PURPOSE: The purpose of this study was to investigate the influence of temperature on the ability of the chondrocytes to produce extracellular matrix (ECM). MATERIALS AND METHODS: Articular chondrocytes were isolated from porcine knee joints. The chondrocytes were cultured at three different temperatures: 32 °C, 37 °C, and 41 °C. The ability to produce ECM was assessed by gene expression analysis, histological, and biochemical evaluation in a pellet culture system. RESULTS: Wet weight of the pellets generated after 21 days, was significantly heavier when cultured at lower temperatures. Picrosirius red staining, employed to evaluate collagen production, was higher at lower temperatures, and safranin-O staining, used to evaluate sulphated glycosaminoglycan (GAG), was lower at 32 °C than at 37 °C and 41 °C. Collagen type IIA1 mRNA expression was markedly up-regulated at 41 °C. However, picrosirius red staining was inhibited at 41 °C. GAG and DNA content were measured by 1,9-dimethylmethylene blue (DMMB) assay and PicoGreen® assay, respectively. The GAG content per pellet was significantly low at 41 °C compared to that at 32 °C and 37 °C. The DNA content per pellet was larger at lower temperatures. The GAG content normalised with the DNA content per pellet was significantly lower at 32 °C compared to that at 37 °C and 41 °C. CONCLUSION: Our results suggest that a culture temperature of approximately 41 °C inhibits ECM production by decreasing DNA content and perhaps by collagen misfolding. Taken together, the optimum temperature for ECM production in articular chondrocytes may be between 32 °C and 37 °C.

Contributions of biarticular myogenic components to the limitation of the range of motion after immobilization of rat knee joint.

BACKGROUND: Muscle atrophy caused by immobilization in the shortened position is characterized by a decrease in the size or cross-sectional area (CSA) of myofibers and decreased muscle length. Few studies have addressed the relationship between limitation of the range of motion (ROM) and the changes in CSA specifically in biarticular muscles after atrophy because of immobilization. We aimed to determine the contribution of 2 distinct muscle groups, the biarticular muscles of the post thigh (PT) and those of the post leg (PL), to the limitation of ROM as well as changes in the myofiber CSAs after joint immobilization surgery. METHODS: Male Wistar rats (n = 40) were randomly divided into experimental and control groups. In the experimental group, the left knee was surgically immobilized by external fixation for 1, 2, 4, 8, or 16 weeks (n = 5 each) and sham surgery was performed on the right knee. The rats in the control groups (n = 3 per time point) did not undergo surgery. After the indicated immobilization periods, myotomy of the PT or PL biarticular muscles was performed and the ROM was measured. The hamstrings and gastrocnemius muscles from the animals operated for 1 or 16 weeks were subjected to morphological analysis. RESULTS: In immobilized knees, the relative contribution of the PT biarticular myogenic components to the total restriction reached 80% throughout the first 4 weeks and decreased thereafter. The relative contribution of the PL biarticular myogenic components remained <20% throughout the immobilization period. The ratio of the myofiber CSA of the immobilized to that of the sham-operated knees was significantly lower at 16 weeks after surgery than at 1 week after surgery only in the hamstrings. CONCLUSIONS: The relative contribution of the PT and PL components to myogenic contracture did not significantly change during the experimental period. However, the ratio of hamstrings CSAs to the sham side was larger than the ratio of medial gastrocnemius CSAs to the sham side after complete atrophy because of immobilization.

Immature articular cartilage and subchondral bone covered by menisci are potentially susceptive to mechanical load.

BACKGROUND: The differences of mechanical and histological properties between cartilage covered by menisci and uncovered by menisci may contribute to the osteoarthritis after meniscectomy and these differences are not fully understood. The purpose of this study is to investigate potential differences in the mechanical and histological properties, and in particular the collagen architecture, of the superficial cartilage layer and subchondral bone between regions covered and uncovered by menisci using immature knee. METHODS: Osteochondral plugs were obtained from porcine tibial cartilage that was either covered or uncovered by menisci. Investigation of the thickness, mechanical properties, histology, and water content of the cartilage as well as micro-computed tomography analysis of the subchondral bone was performed to compare these regions. Collagen architecture was also assessed by using scanning electron microscopy. RESULTS: Compared to the cartilage uncovered by menisci, that covered by menisci was thinner and showed a higher deformity to compression loading and higher water content. In the superficial layer of cartilage in the uncovered regions, collagen fibers showed high density, whereas they showed low density in covered regions. Furthermore, subchondral bone architecture varied between the 2 regions, and showed low bone density in covered regions. CONCLUSIONS: Cartilage covered by menisci differed from that uncovered in both its mechanical and histological properties, especially with regards to the density of the superficial collagen layer. These regional differences may be related to local mechanical environment in normal condition and indicate that cartilage covered by menisci is tightly guarded by menisci from extreme mechanical loading. Our results indicate that immature cartilage degeneration and subchondral microfracture may occur easily to extreme direct mechanical loading in covered region after meniscectomy.

Immunogenomic pan-cancer landscape reveals immune escape mechanisms and immunoediting histories.

Immune reactions in the tumor microenvironment are an important hallmark of cancer, and emerging immune therapies have been proven effective against several types of cancers. To investigate cancer genome-immune interactions and the role of immunoediting or immune escape mechanisms in cancer development, we analyzed 2834 whole genome and RNA sequencing datasets across 31 distinct tumor types with respect to key immunogenomic aspects and provided comprehensive immunogenomic profiles of pan-cancers. We found that selective copy number changes in immune-related genes may contribute to immune escape. Furthermore, we developed an index of the immunoediting history of each tumor sample based on the information of mutations in exonic regions and pseudogenes and evaluated the immunoediting history of each tumor. Our immuno-genomic analyses of pan-cancers have the potential to identify a subset of tumors with immunogenicity and diverse backgrounds or intrinsic pathways associated with their immune status and immunoediting history.

The 40th Anniversary of the Congenital Anomaly Research Center, Kyoto University Graduate School of Medicine.

The Congenital Anomaly Research Center at Kyoto University's Graduate School of Medicine was established in 1975; in 2015 the center celebrated its 40th anniversary. The celebration of this anniversary included three special projects: (1) forming an achievement list, (2) preparing for a specimen exhibition, and (3) holding an anniversary symposium. This special issue of The Anatomical Record is devoting to detailing these anniversary projects. Anat Rec, 301:947-950, 2018. © 2018 Wiley Periodicals, Inc.

Three-dimensional models of the segmented human fetal brain generated by magnetic resonance imaging.

Recent advances in imaging technology have enabled us to obtain more detailed images of the human fetus in a nondestructive and noninvasive manner. Through detailed images, elaborate three-dimensional (3D) models of the developing brain can be reconstructed. The segmentation of the developing brain has been determined by serial sections. Therefore, in this study, we attempted to develop a 3D model of the fetal brain using magnetic resonance image (MRI). MR images from 19 specimens (11 embryonic specimens and eight fetal specimens from 5.2 to 225 mm in crown rump length) were used to reconstruct 3D models of regionalized developing brains. From this analysis, we succeeded in registering a maximum of nine landmarks on MR images and reconstructing 19 sequential models of the regionalized developing brain. To confirm the validity of the landmarks, we also compared our results with three serial sections from the Kyoto Collection; the same morphological characteristics were observed on both serial sections and MRI. The morphological minutiae could be found on MR images, and regionalized models of the developing brain could be reconstructed. These results will be useful for clinical diagnosis of living fetuses in utero.

Integrated genetic and epigenetic analysis of myxofibrosarcoma.

Myxofibrosarcoma (MFS) is a common adult soft tissue sarcoma characterized by an infiltrative growth pattern and a high local recurrence rate. Here we report the genetic and epigenetic landscape of MFS based on the results of whole-exome sequencing (N = 41), RNA sequencing (N = 29), and methylation analysis (N = 41), using 41 MFSs as a discovery set, and subsequent targeted sequencing of 140 genes in the entire cohort of 99 MFSs and 17 MFSs' data from TCGA. Fourteen driver genes are identified, including potentially actionable therapeutic targets seen in 37% of cases. There are frequent alterations in p53 signaling (51%) and cell cycle checkpoint genes (43%). Other conceivably actionable driver genes including ATRX, JAK1, NF1, NTRK1, and novel oncogenic BRAF fusion gene are identified. Methylation patterns cluster into three subtypes associated with unique combinations of driver mutations, clinical outcomes, and immune cell compositions. Our results provide a valuable genomic resource to enable the design of precision medicine for MFS.

A computational tool to detect DNA alterations tailored to formalin-fixed paraffin-embedded samples in cancer clinical sequencing.

Advanced cancer genomics technologies are now being employed in clinical sequencing, where next-generation sequencers are used to simultaneously identify multiple types of DNA alterations for prescription of molecularly targeted drugs. However, no computational tool is available to accurately detect DNA alterations in formalin-fixed paraffin-embedded (FFPE) samples commonly used in hospitals. Here, we developed a computational tool tailored to the detection of single nucleotide variations, indels, fusions, and copy number alterations in FFPE samples. Elaborated multilayer noise filters reduced the inherent noise while maintaining high sensitivity, as evaluated in tumor-unmatched normal samples using orthogonal technologies. This tool, cisCall, should facilitate clinical sequencing in everyday diagnostics. It is available at https://www.ciscall.org .

Ultrasound Parameters for Human Osteoarthritic Subchondral Bone ex Vivo: Comparison with Micro-Computed Tomography Parameters.

The aim of this study was to identify ultrasound parameters reflecting subchondral porosity (Po), subchondral plate thickness (Tpl) and bone volume fraction at the trabecular bone region (BV/TVTb). Sixteen osteoarthritic human lateral femoral condyles were evaluated ex vivo using a 15-MHz pulsed-echo ultrasound 3-D scanning system. The cartilage-subchondral bone (C-B) surface region (layer 1) and inner subchondral bone region (layer 2) were analyzed; we newly introduced entropy (ENT) and correlation (COR) of ultrasound texture parameters of the parallel (x) or perpendicular (z) direction to the C-B interface for this analysis. Po, Tpl and BV/TVTb were evaluated as reference measurements using micro-computed tomography. ENTL1x (ENT of layer 1, x-direction) and ENTL1z were significantly correlated with Po (both r values = 0.58), CORL2x with Tpl (r = -0.73) and CORL2z with BV/TVTb (r = -0.66). These are efficient indicators of the characteristics of osteoarthritis-related subchondral bone; the other texture parameters were not significant.