Polychrome labeling of bone with seven different fluorochromes: Enhancing fluorochrome discrimination by spectral image analysis

Pautke, Christoph; Vogt, Stephan; Tischer, Thomas; Wexel, Gabriele; Deppe, Herbert; Milz, Stefan; Schieker, Matthias; Kolk, Andreas

doi:10.1016/j.bone.2005.05.008

Cited by 111 publications

(87 citation statements)

References 14 publications

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“…Two animals were administered a series of bone labels: calcein green (10 mg/kg; Sigma C0875) at 4 weeks, xylenol orange (100 mg/kg; Sigma 398187) at 8 weeks, and calcein blue (10 mg/kg; Sigma M1255) at 12 weeks postsurgery as subcutaneous injections to identify temporal mineralization patterns [15,29,33,42]. Fixed samples were processed into cryoblocks, and nondecalcified sections (5 lm) were obtained to qualitatively observe repair, the mineral deposition pattern visualized by bone labels, and alkaline phosphatase (AP) staining for osteoblastic activity [21,22,41,44].…”

Section: Vital Bone Labelsmentioning

confidence: 99%

Hydrogel-based Delivery of rhBMP-2 Improves Healing of Large Bone Defects Compared With Autograft

Krishnan

Priddy

Esancy

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background Autologous bone grafting remains the gold standard in the treatment of large bone defects but is limited by tissue availability and donor site morbidity. Recombinant human bone morphogenetic protein-2 (rhBMP-2), delivered with a collagen sponge, is clinically used to treat large bone defects and complications such as delayed healing or nonunion. For the same dose of rhBMP-2, we have shown that a hybrid nanofiber mesh-alginate (NMA-rhBMP-2) delivery system provides longer-term release and increases functional bone regeneration in critically sized rat femoral bone defects compared with a collagen sponge. However, no comparisons of healing efficiencies have been made thus far between this hybrid delivery system and the gold standard of using autograft. Questions/purposes We compared the efficacy of the NMA-rhBMP-2 hybrid delivery system to morselized autograft and hypothesized that the functional regeneration of large bone defects observed with sustained BMP delivery would be at least comparable to autograft treatment as measured by total bone volume and ex vivo mechanical properties. Methods Bilateral critically sized femoral bone defects in rats were treated with either live autograft or with the NMA-rhBMP-2 hybrid delivery system such that each animal received one treatment per leg. Healing was monitored by radiography and histology at 2, 4, 8, and 12 weeks. Defects were evaluated for bone formation by longitudinal micro-CT scans over 12 weeks (n = 14 per group). The bone volume, bone density, and the total new bone formed beyond 2 weeks within the defect were calculated from micro-CT reconstructions and values compared for the 2-, 4-, 8-, and 12-week scans within and across the two treatment groups. Two animals were used for bone labeling with subcutaneously injected dyes at 4, 8, and 12 weeks followed by histology at 12 weeks to

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Section: Vital Bone Labelsmentioning

confidence: 99%

Hydrogel-based Delivery of rhBMP-2 Improves Healing of Large Bone Defects Compared With Autograft

Krishnan

Priddy

Esancy

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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“…Source energy was 70 kV, current was 160 mA, scan time was 20.6 min, and voxel resolution was 8 mm. 28,29 A fixed global threshold method was used in this study based on manufacturer recommendations and preliminary studies, which showed that mineral variation between groups was not high enough to warrant adaptive thresholds. Porosity was calculated as (1-BV/TV), where BV/ TV is the relative bone volume as measured by voxel counting.…”

Section: Microct Analysismentioning

confidence: 99%

Effects of ovariectomy on bone turnover, porosity, and biomechanical properties in ovine compact bone 12 months postsurgery

Kennedy

Brennan

Rackard

et al. 2009

Journal Orthopaedic Research

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Compact bone makes up approximately 80% of the human skeleton by mass; but there are little data available on the effects of increased bone turnover on compact bone mechanical and material properties. This study addresses this question by measuring intracortical remodeling, resorption cavity number, and porosity in an ovariectomized (OVX) sheep model, and measures changes in biomechanical properties. Thirty-eight sheep were divided into two groups. Group 1 were controls (n ¼ 19), and Group 2 were ovariectomized (OVX; n ¼ 19). Fluorochrome dyes were administered intravenously to both groups at five time points over 12 months post-OVX to label sites of bone turnover. At 12 months post-OVX all animals were euthanized. Samples were harvested from the left metatarsal and were analyzed for intracortical bone turnover at five time points, the number of resorption cavities, and the level of intracortical porosity. The effects of these parameters on bone biomechanical properties were then measured. Bone turnover was increased in the OVX group at 6, 9, and 12 months (p < 0.05). Resorption was also higher in the OVX group at 12 months (p < 0.05). Furthermore, porosity was significantly increased in the OVX group at 12 months (p < 0.05). Stiffness and yield strength were reduced in the OVX group compared to controls (p ¼ 0.05). Ultimate compressive strength and work to fracture did not differ between groups. These findings provide new insights into the mechanisms and effects of increased bone turnover on bone material and microstructural properties. Keywords: bone turnover; porosity; ovariectomy; ovine animal model Bone turnover is an important determinant of the structural integrity of bone. It is a crucial process of tissue renewal that normally occurs at an optimal physiological rate for maximum bone strength in a healthy individual. 1 Any change to the optimal bone turnover rate, such as the increase that occurs following ovariectomy (OVX) or menopause, has the potential to dramatically change the bone at microstructural and material levels. High bone turnover can have the effect of increasing remodeling spaces, accelerating bone loss, increasing stress concentrations, and increasing cortical porosity, each of which can undermine bone mechanical properties. A precise definition of bone quality remains elusive, however; bone turnover and microarchitecture are considered to be two important contributors to this phenomenon along with mineralization, microdamage, and collagen content. Thus, these parameters are important considerations in the pathophysiology of skeletal diseases such as osteoporosis and the mechanisms that underlie fracture. 2 Previous studies have shown that bone turnover has a direct influence on fracture risk. 3 It is thought that compact bone is affected by accelerated turnover in two ways. First, more mineralized bone is removed and replaced with younger, less mineralized bone, which reduces the material's local stiffness. Second, the presence of more resorption cavities creates stress concen...

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“…To avoid cardiovascular side effects of an additional general anesthesia for intravenous polychrome application, we choose the subcutaneous application as described by another group (Pautke et al 2005).…”

Section: Assessmentsmentioning

confidence: 99%

Osseointegration of Titanium Prostheses on the Stapes Footplate

Neudert

Beleites

Ney

et al. 2010

JARO

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The success of middle ear reconstructive surgery depends on stable coupling between the prosthesis and residual ossicles. To establish a stable fixed point on the stapes footplate for subsequent prosthesis reconstruction, a titanium footplate anchor was coated with osteoinductive substances to induce a controlled osseointegration on the footplate. Various studies have shown that collagen-based matrices with and without bone growth and differentiation factors can induce and enhance bone formation and consequently increase implant stability. The ears of 23 oneyear-old Merino sheep (n=46) were divided into five groups and implanted with a specially designed footplate anchor. The surface of each implant was modified by applying a collagenous matrix (collagen I or II) either with immobilized bone morphogenic protein (BMP-4) or transforming growth factor-ß, respectively, to stimulate osteoblastic activation and differentiation on the stapes footplate with subsequent osseointegration. Polychrome labeling was used to assess new bone formation and remodeling during the study. After study termination on day 84, synchrotron radiation-based computed microtomography and histomorphometry were used to identify bone implant contact. Eight implants showed radiographical and/or histological evidence of integration by newly formed bone. An osseointegration could histologically be proven in two of these eight specimens, and additional ectopic bone formations were seen in another 21 specimens. In all animals, bone turnover on the footplate was proven by polychrome labeling. This study proves the general ability to induce a controlled osseointegration of titanium implants biologically activated with artificial extracellular matrices on their surfaces on the stapes footplate in a mammalian organism.

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Polychrome labeling of bone with seven different fluorochromes: Enhancing fluorochrome discrimination by spectral image analysis

Cited by 111 publications

References 14 publications

Hydrogel-based Delivery of rhBMP-2 Improves Healing of Large Bone Defects Compared With Autograft

Hydrogel-based Delivery of rhBMP-2 Improves Healing of Large Bone Defects Compared With Autograft

Effects of ovariectomy on bone turnover, porosity, and biomechanical properties in ovine compact bone 12 months postsurgery

Osseointegration of Titanium Prostheses on the Stapes Footplate

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