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Bone Measurements by Peripheral Quantitative Computed Tomography in Rodents. Methods Mol Biol 2019; 1914:533-558. [PMID: 30729485 DOI: 10.1007/978-1-4939-8997-3_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
Abstract
This chapter provides information for the in vivo use of peripheral quantitative computed tomography in rats and mice to determine bone density and cortical geometric data, including suggestions for study design, instrument setting, and data interpretation. This update also provides guidance for the use of pQCT to extract muscle and fat cross-sectional area information from the bone scans.
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Yakar S, Isaksson O. Regulation of skeletal growth and mineral acquisition by the GH/IGF-1 axis: Lessons from mouse models. Growth Horm IGF Res 2016; 28:26-42. [PMID: 26432542 PMCID: PMC4809789 DOI: 10.1016/j.ghir.2015.09.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/16/2015] [Accepted: 09/24/2015] [Indexed: 12/31/2022]
Abstract
The growth hormone (GH) and its downstream mediator, the insulin-like growth factor-1 (IGF-1), construct a pleotropic axis affecting growth, metabolism, and organ function. Serum levels of GH/IGF-1 rise during pubertal growth and associate with peak bone acquisition, while during aging their levels decline and associate with bone loss. The GH/IGF-1 axis was extensively studied in numerous biological systems including rodent models and cell cultures. Both hormones act in an endocrine and autocrine/paracrine fashion and understanding their distinct and overlapping contributions to skeletal acquisition is still a matter of debate. GH and IGF-1 exert their effects on osteogenic cells via binding to their cognate receptor, leading to activation of an array of genes that mediate cellular differentiation and function. Both hormones interact with other skeletal regulators, such as sex-steroids, thyroid hormone, and parathyroid hormone, to facilitate skeletal growth and metabolism. In this review we summarized several rodent models of the GH/IGF-1 axis and described key experiments that shed new light on the regulation of skeletal growth by the GH/IGF-1 axis.
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Affiliation(s)
- Shoshana Yakar
- David B. Kriser Dental Center, Department of Basic Science and Craniofacial Biology New York University College of Dentistry New York, NY 10010-408
| | - Olle Isaksson
- Institute of Medicine, Sahlgrenska University Hospital, University of Gothenburg, SE-41345 Gothenburg, Sweden
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3
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Lemon G, Reinwald Y, White LJ, Howdle SM, Shakesheff KM, King JR. Interconnectivity analysis of supercritical CO₂-foamed scaffolds. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2012; 106:139-149. [PMID: 20837373 DOI: 10.1016/j.cmpb.2010.08.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 05/18/2010] [Accepted: 08/15/2010] [Indexed: 05/29/2023]
Abstract
This paper describes a computer algorithm for the determination of the interconnectivity of the pore space inside scaffolds used for tissue engineering. To validate the algorithm and its computer implementation, the algorithm was applied to a computer-generated scaffold consisting of a set of overlapping spherical pores, for which the interconnectivity was calculated exactly. The algorithm was then applied to micro-computed X-ray tomography images of supercritical CO(2)-foamed scaffolds made from poly(lactic-co-glycolic acid) (PLGA), whereby the effect of using different weight average molecular weight polymer on the interconnectivity was investigated.
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Affiliation(s)
- Greg Lemon
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
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4
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Gasser JA, Willnecker J. Bone measurements by peripheral quantitative computed tomography in rodents. Methods Mol Biol 2012; 816:477-498. [PMID: 22130945 DOI: 10.1007/978-1-61779-415-5_28] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This chapter provides information for the use of peripheral quantitative computed tomography in small animals, including suggestions for study design, instrument setting, and data interpretation.
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Affiliation(s)
- Jürg A Gasser
- Department of Musculoskeletal Diseases, Novartis Institutes for BioMedical Research, Basel, Switzerland.
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5
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Abstract
In nerve tissue engineering, scaffolds act as carriers for cells and biochemical factors and as constructs providing appropriate mechanical conditions. During nerve regeneration, new tissue grows into the scaffolds, which degrade gradually. To optimize this process, researchers must study and analyze various morphological and structural features of the scaffolds, the ingrowth of nerve tissue, and scaffold degradation. Therefore, visualization of the scaffolds as well as the generated nerve tissue is essential, yet challenging Visualization techniques currently used in nerve tissue engineering include electron microscopy, confocal laser scanning microscopy (CLSM), and micro-computed tomography (micro-CT or μCT). Synchrotron-based micro-CT (SRμCT) is an emerging and promising technique, drawing considerable recent attention. Here, we review typical applications of these visualization techniques in nerve tissue engineering. The promise, feasibility, and challenges of SRμCT as a visualization technique applied to nerve tissue engineering are also discussed.
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Abstract
With recent advances in molecular medicine and disease treatment in osteoporosis, quantitative image processing of three-dimensional bone structures is critical in the context of bone quality assessment. Biomedical imaging technology such as MRI or CT is readily available, but few attempts have been made to expand the capabilities of these systems by integrating quantitative analysis tools and by exploring structure-function relationships in a hierarchical fashion. Nevertheless, such quantitative end points are an important factor for success in basic research and in the development of novel therapeutic strategies. CT is key to these developments, as it images and quantifies bone in three dimensions and provides multiscale biological imaging capabilities with isotropic resolutions of a few millimeters (clinical CT), a few tens of micrometers (microCT) and even as high as 100 nanometers (nanoCT). The technology enables the assessment of the relationship between microstructural and ultrastructural measures of bone quality and certain diseases or therapies. This Review focuses on presenting strategies for three-dimensional approaches to hierarchical biomechanical imaging in the study of microstructural and ultrastructural bone failure. From this Review, it can be concluded that biomechanical imaging is extremely valuable for the study of bone failure mechanisms at different hierarchical levels.
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Affiliation(s)
- Ralph Müller
- Institute for Biomechanics, Department of Mechanical and Process Engineering, ETH Zürich, Zürich, Switzerland.
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Zagorchev L, Mulligan-Kehoe MJ. Molecular imaging of vessels in mouse models of disease. Eur J Radiol 2009; 70:305-11. [PMID: 19304428 PMCID: PMC2757633 DOI: 10.1016/j.ejrad.2009.01.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 01/14/2009] [Indexed: 12/29/2022]
Abstract
Vascular imaging of angiogenesis in mouse models of disease requires multi modal imaging hardware capable of targeting both structure and function at different physical scales. The three dimensional (3D) structure and function vascular information allows for accurate differentiation between biological processes. For example, image analysis of vessel development in angiogenesis vs. arteriogenesis enables more accurate detection of biological variation between subjects and more robust and reliable diagnosis of disease. In the recent years a number of micro imaging modalities have emerged in the field as preferred means for this purpose. They provide 3D volumetric data suitable for analysis, quantification, validation, and visualization of results in animal models. This review highlights the capabilities of microCT, ultrasound and microPET for multimodal imaging of angiogenesis and molecular vascular targets in a mouse model of tumor angiogenesis. The basic principles of the imaging modalities are described and experimental results are presented.
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Affiliation(s)
- Lyubomir Zagorchev
- Angiogenesis Research Center, Dartmouth Medical School, Lebanon, NH
- Clinical Sites Research Program, Philips Research North America, Briarcliff Manor, NY
| | - Mary J. Mulligan-Kehoe
- Angiogenesis Research Center, Dartmouth Medical School, Lebanon, NH
- Department of Surgery, Vascular Section, Dartmouth Medical School, Lebanon, NH
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8
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Ghanem A, Röll W, Hashemi T, Dewald O, Djoufack PC, Fink KB, Schrickel J, Lewalter T, Lüderitz B, Tiemann K. Echocardiographic assessment of left ventricular mass in neonatal and adult mice: accuracy of different echocardiographic methods. Echocardiography 2007; 23:900-7. [PMID: 17069614 DOI: 10.1111/j.1540-8175.2006.00323.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Echocardiography is an established method to estimate left-ventricular mass (LVM) in mice. Accuracy is determined by cardiac size and morphology and influenced by mathematical models. We investigated accuracy of three common algorithms in three early developmental stages. High-resolution echocardiography was performed in 35 C57/BL6-mice. Therefore, two-dimensional-guided M-mode echocardiography and parasternal short- and long-axis views in B-mode were obtained. LVM was assessed in vivo applying Penn (P), Area Length (AL), and Truncated Ellipsoid (TE) algorithms and validated with histomorphometry. Regression analysis of all mice showed fair estimation of LVM assessed with M-mode-based Penn algorithm (y = 0.6*x - 0.12, r: 0.71). In contrast two-dimensional assessment of LVM revealed close linear relationship with histomorphometry (y(AL)= 1.21*x - 12.1, r: 0.88, y(TE)= 1.38*x - 2.88, r: 0.86). Bias was lowest for LVM-AL at diastole underestimating 3.2%. In concordance with the summarized data, LVM-P revealed lower regression coefficients and significant underestimation in all three subgroups. Small hearts (<50 mg, n = 12) correlated best with LVM-AL at systole. Hearts of adolescent (50-75 mg, n = 13) and adult (75-100 mg, n = 10) mice revealed close linear relationship with LVM-AL and LVM-TE at diastole. Echocardiographic assessment of LVM is feasible in hearts weighting less than 50 mg and can be estimated best in systole. Hearts weighting more than 50 mg are estimated most accurately by means of LVM-AL at diastole.
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Affiliation(s)
- Alexander Ghanem
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, Bonn, Germany
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van Lenthe GH, Stauber M, Müller R. Specimen-specific beam models for fast and accurate prediction of human trabecular bone mechanical properties. Bone 2006; 39:1182-9. [PMID: 16949356 DOI: 10.1016/j.bone.2006.06.033] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 05/19/2006] [Accepted: 06/23/2006] [Indexed: 11/19/2022]
Abstract
Direct assessment of bone competence in vivo is not possible, hence, it is inevitable to predict it using appropriate simulation techniques. Although accurate estimates of bone competence can be obtained from micro-finite element models (muFE), it is at the expense of large computer efforts. In this study, we investigated the application of structural idealizations to represent individual trabeculae by single elements. The objective was to implement and validate this technique. We scanned 42 human vertebral bone samples (10 mm height, 8 mm diameter) with micro-computed tomography using a 20 microm resolution. After scanning, direct mechanical testing was performed. Topological classification and dilation-based algorithms were used to identify individual rods and plates. Two FE models were created for each specimen. In the first one, each rod-like trabecula was modeled with one thickness-matched beam; each plate-like trabecula was modeled with several beams. From a simulated compression test, assuming one isotropic tissue modulus for all elements, the apparent stiffness was calculated. After reducing the voxel size to 40 microm, a second FE model was created using a standard voxel conversion technique. Again, one tissue modulus was assumed for all elements in all models, and a compression test was simulated. Bone volume fraction ranged from 3.7% to 19.5%; Young's moduli from 43 MPa to 649 MPa. Both models predicted measured apparent moduli equally well (R2 = 0.85), and were in excellent agreement with each other (R2 = 0.97). Tissue modulus was estimated at 9.0 GPa and 10.7 GPa for the beam FE and voxel FE models, respectively. On average, the beam models were solved in 219 s, reducing CPU usage up to 1150-fold as compared to 40 microm voxel FE models. Relative to 20 microm voxel models 10,000-fold reductions can be expected. The presented beam FE model is an abstraction of the intricate real trabecular structure using simple cylindrical beam elements. Nevertheless, it enabled an accurate prediction of global mechanical properties of microstructural bone. The strong reduction in CPU time provides the means to increase throughput, to analyze multiple loading configuration and to increase sample size, without increasing computational costs. With upcoming in vivo high-resolution imaging systems, this model has the potential to become a standard for mechanical characterization of bone.
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Affiliation(s)
- G H van Lenthe
- Institute for Biomedical Engineering, University and ETH Zürich, Moussonstrasse 18, 8044 Zürich, Switzerland.
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Abstract
Although biomedical imaging technology is now readily available, few attempts have been made to expand the capabilities of these systems by adding not only quantitative but also functional analysis tools combining microimaging with time-lapsed mechanical testing. An area of special interest is multiscale functional imaging of trabecular bone to assess the relative importance of bone "quality" in the assessment of the mechanical competence of bone. First, relevant studies dealing with hierarchical imaging of trabecular bone and classic analyses such as quantitative morphometry and finite-element analysis to predict bone strength are reviewed. Second, studies are presented investigating failure mechanisms of three-dimensional trabecular bone through dynamic, time-lapsed microimaging, including image-guided techniques developed for this purpose and utilizing microcompression. For the first time, these allow the direct three-dimensional visualization and quantification of failure initiation and progression at the microstructural level.
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Affiliation(s)
- Ralph Müller
- Institute for Biomedical Engineering, University and ETH Zürich, Switzerland.
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Abstract
In this report, we present a new noninvasive 3-dimensional (3D) imaging technology for in vivo monitoring of the skeletal development of mice: flat-panel volumetric Computed Tomography (fpvCT). Long-term investigations of 4 mice are presented, with up to 14 scans of each mouse from postnatal day 0 to 86. Examinations of a newborn and an adult mouse, performed with fpvCT and clinical multislice CT (MSCT), demonstrate the superior image quality of high-resolution fpvCT.
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Affiliation(s)
- Martin Obert
- Universitätsklinikum Giessen, Abteilung Neuroradiologie, D-35385 Giessen, Germany.
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12
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Guldberg RE, Ballock RT, Boyan BD, Duvall CL, Lin AS, Nagaraja S, Oest M, Phillips J, Porter BD, Robertson G, Taylor WR. Analyzing bone, blood vessels, and biomaterials with microcomputed tomography. ACTA ACUST UNITED AC 2004; 22:77-83. [PMID: 14699940 DOI: 10.1109/memb.2003.1256276] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- R E Guldberg
- Woodruff School of Mechanical Engineering, Coulter School of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405, USA.
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Sjögren K, Sheng M, Movérare S, Liu JL, Wallenius K, Törnell J, Isaksson O, Jansson JO, Mohan S, Ohlsson C. Effects of liver-derived insulin-like growth factor I on bone metabolism in mice. J Bone Miner Res 2002; 17:1977-87. [PMID: 12412805 DOI: 10.1359/jbmr.2002.17.11.1977] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Insulin-like growth factor (IGF) I is an important regulator of both skeletal growth and adult bone metabolism. To better understand the relative importance of systemic IGF-I versus locally expressed IGF-I we have developed a transgenic mouse model with inducible specific IGF-I gene inactivation in the liver (LI-IGF-I-/-). These mice are growing normally up to 12 weeks of age but have a disturbed carbohydrate and lipid metabolism. In this study, the long-term effects of liver-specific IGF-I inactivation on skeletal growth and adult bone metabolism were investigated. The adult (week 8-55) axial skeletal growth was decreased by 24% in the LI-IGF-I-/- mice whereas no major reduction of the adult appendicular skeletal growth was seen. The cortical cross-sectional bone area, as measured in the middiaphyseal region of the long bones, was decreased in old LI-IGF-I-/- mice. This reduction in the amount of cortical bone was caused mainly by decreased periosteal circumference and was associated with a weaker bone determined by a decrease in ultimate load. In contrast, the amount of trabecular bone was not decreased in the LI-IGF-I-/- mice. DNA microarray analysis of 30-week-old LI-IGF-I-/- and control mice indicated that only four genes were regulated in bone whereas approximately 40 genes were regulated in the liver, supporting the hypothesis that liver-derived IGF-I is of minor importance for adult bone metabolism. In summary, liver-derived IGF-I exerts a small but significant effect on cortical periosteal bone growth and on adult axial skeletal growth while it is not required for the maintenance of the trabecular bone in adult mice.
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Affiliation(s)
- Klara Sjögren
- RCEM, Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden
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15
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Eckstein F, Lochmüller EM, Koller B, Wehr U, Weusten A, Rambeck W, Hoeflich A, Wolf E. Body composition, bone mass and microstructural analysis in GH-transgenic mice reveals that skeletal changes are specific to bone compartment and gender. Growth Horm IGF Res 2002; 12:116-125. [PMID: 12175649 DOI: 10.1054/ghir.2002.0272] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Experimental and clinical studies suggest that high serum levels of growth hormone (GH) increase cortical but not trabecular bone. We studied body composition and bone structure in transgenic mice (MT-bGH) with systemic overexpression of GH. Body composition was examined with dual-energy X-ray absorptiometry (DXA), ashing, and chemical analysis, and the femora with DXA and micro computerized tomography. The absolute fat and bone tissue contents were significantly higher in GH transgenic mice vs controls (P < or = 0.05), but no significant difference was noted when normalizing the values to body weight. Male transgenics displayed no change in apparent (volumetric) femoral bone density, relative cortical area and trabecular bone volume fraction. Female transgenic mice demonstrated an increase in apparent femoral density and in trabecular bone volume fraction (+130%; P < or = 0.01). The mineralized tissue matrix density was decreased in male and female transgenic mice (P < or = 0.05). The results show that chronic GH excess affects trabecular bone in a gender-specific manner and that bone changes depend on the compartment investigated.
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Affiliation(s)
- F Eckstein
- Musculoskeletal Research Group, Institute of Anatomy, Ludwig-Maximilians-Universität München, Pettenkoferstr. 11, Germany.
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Alexander JM, Bab I, Fish S, Müller R, Uchiyama T, Gronowicz G, Nahounou M, Zhao Q, White DW, Chorev M, Gazit D, Rosenblatt M. Human parathyroid hormone 1-34 reverses bone loss in ovariectomized mice. J Bone Miner Res 2001; 16:1665-73. [PMID: 11547836 DOI: 10.1359/jbmr.2001.16.9.1665] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The experimental work characterizing the anabolic effect of parathyroid hormone (PTH) in bone has been performed in nonmurine ovariectomized (OVX) animals, mainly rats. A major drawback of these animal models is their inaccessibility to genetic manipulations such as gene knockout and overexpression. Therefore, this study on PTH anabolic activity was carried out in OVX mice that can be manipulated genetically in future studies. Adult Swiss-Webster mice were OVX, and after the fifth postoperative week were treated intermittently with human PTH(1-34) [hPTH(1-34)] or vehicle for 4 weeks. Femoral bones were evaluated by microcomputed tomography (microCT) followed by histomorphometry. A tight correlation was observed between trabecular density (BV/TV) determinations made by both methods. The BV/TV showed >60% loss in the distal metaphysis in 5-week and 9-week post-OVX, non-PTH-treated animals. PTH induced a approximately 35% recovery of this loss and a approximately 40% reversal of the associated decreases in trabecular number (Tb.N) and connectivity. PTH also caused a shift from single to double calcein-labeled trabecular surfaces, a significant enhancement in the mineralizing perimeter and a respective 2- and 3-fold stimulation of the mineral appositional rate (MAR) and bone formation rate (BFR). Diaphyseal endosteal cortical MAR and thickness also were increased with a high correlation between these parameters. These data show that OVX osteoporotic mice respond to PTH by increased osteoblast activity and the consequent restoration of trabecular network. The Swiss-Webster mouse model will be useful in future studies investigating molecular mechanisms involved in the pathogenesis and treatment of osteoporosis, including the mechanisms of action of known and future bone antiresorptive and anabolic agents.
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Affiliation(s)
- J M Alexander
- Division of Bone and Mineral Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02115, USA
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Abstract
We present an archetypal digital atlas of the mouse embryo based on microscopic magnetic resonance imaging. The atlas is composed of three modules: (1) images of fixed embryos 6 to 15.5 days postconception (dpc) [Theiler Stages (TS) 8 to 24]; (2) an annotated atlas of the anterior portion of a 13.5 dpc (TS 22) mouse with anatomical structures delineated and linked to explanatory files; and (3) three-dimensional renderings of the entire 13.5 dpc embryo and specific organ systems. The explanatory files include brief descriptions of the structure at each volume element in the image and links to 3D reconstructions, allowing visualization of the shape of the isolated structures. These files can also contain or be linked to other types of information and data including detailed anatomical and physiological information about structures with pointers to online references, relationships between structures, temporal characteristics (cell lineage patterns, size, and shape changes), and gene expression patterns (both spatial and temporal). As an example, we have "painted" in the expression pattern of Dlx5/Dlx6 genes. This digital atlas provides a means to put specific data within the context of normal specimen anatomy, to analyze the information in 3D, and to examine relationships between different types of information.
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Affiliation(s)
- M Dhenain
- Division of Biology, Beckman Institute, Pasadena, California 91125, USA
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Stammberger T, Eckstein F, Michaelis M, Englmeier KH, Reiser M. Interobserver reproducibility of quantitative cartilage measurements: comparison of B-spline snakes and manual segmentation. Magn Reson Imaging 1999; 17:1033-42. [PMID: 10463654 DOI: 10.1016/s0730-725x(99)00040-5] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of this work was to develop a segmentation technique for thickness measurements of the articular cartilage in MR images and to assess the interobserver reproducibility of the method in comparison with manual segmentation. The algorithm is based on a B-spline snakes approach and is able to delineate the cartilage boundaries in real time and with minimal user interaction. The interobserver reproducibility of the method, ranging from 3.3 to 13.6% for various section orientations and joint surfaces, proved to be significantly superior to manual segmentation.
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Affiliation(s)
- T Stammberger
- Institute for Medical Informatics, GSF National Research Center, Oberschleissheim, Germany.
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