Quantification of osteocyte lacunar density and anisotropy of vascular canals in compact bone

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Quantification of osteocyte lacunar density and anisotropy of vascular canals in compact bone -Introduction, bone structure, remodelation, osteoporosis, Remodelling of Haversian bone may result in both spatial and temporal variability of osteocyte lacunar density and arrangement of vascular canals. -Parameters and methods in bone histomorphometry, tetracycline labeling, disector The most commonly used histomorphometric parameters: [1] 1- Structural parameters Measures that describe the biopsy specimen -Core width (mm) C.Wi Overall size of the biopsy specimen, refers to the width of the entire biopsy specimen or core. It is the distance between the inner and outer periosteal surfaces -Cortical width (μm) Ct.Wi Distance between periosteal and endocortical surfaces, he sum of

the widths of inner and outer cortices of the biopsy specimen. -Bone volume / tissue volume (%) BV/TV Space taken up by mineralized and unmineralized bone relative to the total size of a bone compartmen, is cancellous bone volume as a percentage of tissue volume. The numerator includes matrix, whether mineralized or not, and the denominator includes cancellous bone, marrow, and associated soft tissue. Measures that describe the configuration of trabeculae in space: Trabecular thickness (μm) Tb.Th Is the mean distance across individual trabeculae Trabecular number (/mm) Tb.N Number of trabeculae that a line through a trabecular compartment would hit per millimeter of its length, (BV/TV)/Tb.Th - Trabecular separation Tb.Sp Is the mean distance between individual trabeculae 2-

Static formation parameters Osteoid thickness (μm) O.Th Distance between the surface of the osteoid seam and mineralized bone Osteoid surface / bone surface (%) OS/BS Percentage of bone surface covered by osteoid Osteoid volume / bone volume (%) OV/BV Percentage of bone volume consisting of unmineralized osteoid Osteoblast surface / bone surface (%) Ob.S/BS Percentage of bone surface covered by osteoblasts Wall thickness (μm) W.Th Mean thickness of bone tissue that has been deposited at a remodeling site, is the mean distance between resting trabecular surfaces and cement lines 3- Dynamic formation parameters Mineralizing surface / bone surface (%) MS/BS Percentage of bone surface showing mineralizing activity Mineral apposition rate (μm/d) MAR Distance between two

tetracycline labels divided by the length of the labeling interval Mineralization lag time (d) Mlt Time interval between the deposition and mineralization of matrix Bone formation rate / bone surface (μm3×μm−2*y−1) BFR/BS Amount of bone formed per year on a given bone surface 4- Static resorption parameters Eroded surface / bone surface (%) ES/BS Percentage of bone surface presenting a scalloped appearance Osteoclast surface / bone surface (%) Oc.S/BS Percentage of bone surface covered by osteoclasts -Aims of the study The aim of the study was to assess locally specific numerical density of lacunes with a three-dimensional unbiased counting method and to analyze anisotropy of profiles of vascular canals in an embedded section of human tibia. -Material and methods –

optical disector – Delaunay triangulation - bone biopsy An undecalcified 150 micrometers thick transversal section was sawed from the diaphysis of tibia of a 70-year-old female, grinded to a 70-80 micrometers thick section, polished, stained with basic fuchsin, and observed with an optical microscope. We quantified numerical density of osteocyte lacunes in compact bone underlying the lateral, medial, and posterior surface. Image frames (n=42) were sampled in an systematic uniform random manner from cortical and medullar layer round the tibial circumference. Each of the layers comprised one half of the local thickness of the bone section. Series of seven optical sections registered with respect to the Z-axis were photographed in each image frame. The unbiased counting rule of