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      1. Author :
        Greg M. Thurber, Jose L. Figueiredo, Ralph Weissleder
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        PLoS One
      6. Products :
      7. Volume :
        4
      8. Issue :
        11
      9. Page Numbers :
        N/A
      10. Research Area :
        Cancer
      11. Keywords :
        FLIM; fluorescent intravital live microscopy; in vivo imaging; multicolor FLIM
      12. Abstract :
        BACKGROUND: Complete surgical resection of neoplasia remains one of the most efficient tumor therapies. However, malignant cell clusters are often left behind during surgery due to the inability to visualize and differentiate them against host tissue. Here we establish the feasibility of multicolor fluorescent intravital live microscopy (FILM) where multiple cellular and/or unique tissue compartments are stained simultaneously and imaged in real time.

        METHODOLOGY/PRINCIPAL FINDINGS: Theoretical simulations of imaging probe localization were carried out for three agents with specificity for cancer cells, stromal host response, or vascular perfusion. This transport analysis gave insight into the probe pharmacokinetics and tissue distribution, facilitating the experimental design and allowing predictions to be made about the localization of the probes in other animal models and in the clinic. The imaging probes were administered systemically at optimal time points based on the simulations, and the multicolor FILM images obtained in vivo were then compared to conventional pathological sections. Our data show the feasibility of real time in vivo pathology at cellular resolution and molecular specificity with excellent agreement between intravital and traditional in vitro immunohistochemistry.

        CONCLUSIONS/SIGNIFICANCE: Multicolor FILM is an accurate method for identifying malignant tissue and cells in vivo. The imaging probes distributed in a manner similar to predictions based on transport principles, and these models can be used to design future probes and experiments. FILM can provide critical real time feedback and should be a useful tool for more effective and complete cancer resection.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/19956597
      14. Call Number :
        PKI @ sarah.piper @
      15. Serial :
        4516
      1. Author :
        von Wallbrunn A, Höltke C, Zühlsdorf M, Heindel W, Schäfers M, Bremer C
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2007
      5. Publication :
        European Journal of Nuclear Medicine and Molecular Imaging
      6. Products :
      7. Volume :
        34
      8. Issue :
        5
      9. Page Numbers :
        N/A
      10. Research Area :
        Cancer
      11. Keywords :
        Optical imaging; Fluorescence-mediated tomography; Fluorescence reflectance imaging; in vivo imaging
      12. Abstract :
        PURPOSE: Optical imaging would be desirable for cancer diagnostics since it can potentially resolve relevant oncological target structures in vivo. We therefore synthesised an alpha v beta(3) targeted fluorochrome and imaged tumour xenografts with different alpha v beta(3) expression levels using both planar and tomographic optical imaging methods.
        METHODS: An alpha v beta(3)-targeted RGD peptide was labelled with a cyanine dye (Cy 5.5). Binding of the optical tracer was tested on M21 melanoma (n=5), HT-1080 fibrosarcoma (n=6) and MCF-7 adenocarcinoma (n=5) cells and their tumour xenografts. All optical imaging studies were performed using two-dimensional planar fluorescence reflectance imaging (FRI) technology and three-dimensional fluorescence-mediated tomography (FMT).
        RESULTS: In vitro, the peptide-dye conjugate showed a clear binding affinity to alpha v beta(3)-positive M21 and HT-1080 cells while alpha v beta(3)-negative MCF-7 cells and pre-dosing with the free RGD peptide revealed little to no fluorescence. In vivo, tumour xenografts were clearly visualised by FRI and FMT up to 24 h post injection. FMT allowed quantification of the fluorochrome distribution in deeper tissue sections showing an average fluorochrome concentration of 417.61 +/- 105.82 nM Cy 5.5 (M21), 353.68 +/- 54.02 nM Cy 5.5 (HT-1080) and 262.83 +/- 155.36 nM Cy 5.5 (MCF-7) in the target tissue 60 min after tracer administration. Competition with the free RGD peptide resulted in a reduction in the fluorochrome concentration in M21 tumour tissue (294.35 +/- 84.27 nM).
        CONCLUSION: RGD-Cy 5.5 combined with novel tomographic optical imaging methods allows non-invasive imaging of tumour-associated alpha v beta(3) expression and may thus be a promising strategy for sensitive evaluation of tumour target expression.
      13. URL :
        In vivo imaging of integrin alpha v beta 3 expression using fluorescence-mediated tomography
      14. Call Number :
        PKI @ sarah.piper @
      15. Serial :
        4521
      1. Author :
        Jan Grimm; David G. Kirsch; Stephen D. Windsor; Carla F. Bender Kim; Philip M. Santiago; Vasilis Ntziachristos; Tyler Jacks; Ralph Weissleder
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2005
      5. Publication :
        PNAS
      6. Products :
      7. Volume :
        102
      8. Issue :
        40
      9. Page Numbers :
        N/A
      10. Research Area :
        Cancer
      11. Keywords :
        gene expression profiling; lung cancer; immunohistochemistry; Western blotting; in vivo imaging; moleuclar imaging; fluorescence molecular tomography
      12. Abstract :
        Using gene expression profiling, we identified cathepsin cysteine proteases as highly up-regulated genes in a mouse model of human lung adenocarcinoma. Overexpression of cathepsin proteases in these lung tumors was confirmed by immunohistochemistry and Western blotting. Therefore, an optical probe activated by cathepsin proteases was selected to detect murine lung tumors in vivo as small as 1 mm in diameter and spatially separated. We generated 3D maps of the fluorescence signal and fused them with anatomical computed tomography images to show a close correlation between fluorescence signal and tumor burden. By serially imaging the same mouse, optical imaging was used to follow tumor progression. This study demonstrates the capability for molecular imaging of a primary lung tumor by using endogenous proteases expressed by a tumor. It also highlights the feasibility of using gene expression profiling to identify molecular targets for imaging lung cancer.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1242291/
      14. Call Number :
        PKI @ sarah.piper @
      15. Serial :
        4524
      1. Author :
        Kenneth M. Kozloff, Luisa Quinti, Somying Patntirapong, Peter V. Hauschka, Ching-Hsuan Tung, Ralph Weissleder and Umar Mahmood
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2009
      5. Publication :
        Bone
      6. Products :
      7. Volume :
        44
      8. Issue :
        2
      9. Page Numbers :
        N/A
      10. Research Area :
        Physiology
      11. Keywords :
        FMT; ProSense; OsteoSense; bone; osteoclast; cathepsin K; non-invasive imaging; molecular imaging; fluorescence; in vivo imaging
      12. Abstract :
        Osteoclasts degrade bone matrix by demineralization followed by degradation of type I collagen through secretion of the cysteine protease, cathepsin K. Current imaging modalities are insufficient for sensitive observation of osteoclast activity, and in vivo live imaging of osteoclast resorption of bone has yet to be demonstrated. Here, we describe a near-infrared fluorescence reporter probe whose activation by cathepsin K is shown in live osteoclast cells and in mouse models of development and osteoclast upregulation. Cathepsin K probe activity was monitored in live osteoclast cultures and correlates with cathepsin K gene expression. In ovariectomized mice, cathepsin K probe upregulation precedes detection of bone loss by micro-computed tomography. These results are the first to demonstrate non-invasive visualization of bone degrading enzymes in models of accelerated bone loss, and may provide a means for early diagnosis of upregulated resorption and rapid feedback on efficacy of treatment protocols prior to significant loss of bone in the patient.
      13. URL :
        http://www.thebonejournal.com/article/S8756-3282(08)00816-8/abstract
      14. Call Number :
        PKI @ sarah.piper @
      15. Serial :
        4526
      1. Author :
        Kozloff KM, Volakis LI, Marini JC and Caird MS
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2010
      5. Publication :
        Journal of Bone and Mineral Research
      6. Products :
      7. Volume :
        25
      8. Issue :
        8
      9. Page Numbers :
        N/A
      10. Research Area :
        Physiology
      11. Keywords :
        FMT; bone; OsteoSense; FRFP; in vivo imaging
      12. Abstract :
        Bisphosphonate use has expanded beyond traditional applications to include treatment of a variety of low-bone-mass conditions. Complications associated with long-term bisphosphonate treatment have been noted, generating a critical need for information describing the local bisphosphonate-cell interactions responsible for these observations. This study demonstrates that a fluorescent bisphosphonate analogue, far-red fluorescent pamidronate (FRFP), is an accurate biomarker of bisphosphonate deposition and retention in vivo and can be used to monitor site-specific local drug concentration. In vitro, FRFP is competitively inhibited from the surface of homogenized rat cortical bone by traditional bisphosphonates. In vivo, FRFP delivery to the skeleton is rapid, with fluorescence linearly correlated with bone surface area. Limb fluorescence increases linearly with injected dose of FRFP; injected FRFP does not interfere with binding of standard bisphosphonates at the doses used in this study. Long-term FRFP retention studies demonstrated that FRFP fluorescence decreases in conditions of normal bone turnover, whereas fluorescence was retained in conditions of reduced bone turnover, demonstrating preservation of local FRFP concentration. In the mandible, FRFP localized to the alveolar bone and bone surrounding the periodontal ligament and molar roots, consistent with findings of osteonecrosis of the jaw. These findings support a role for FRFP as an effective in vivo marker for bisphosphonate site-specific deposition, turnover, and long-term retention in the skeleton.
      13. URL :
        http://www.ncbi.nlm.nih.gov/pubmed/20200982
      14. Call Number :
        PKI @ sarah.piper @
      15. Serial :
        4527
      1. Author :
        Kenneth M Kozloff, Ralph Weissleder and Umar Mahmood
      2. Title :
      3. Type :
        Journal Article
      4. Year :
        2007
      5. Publication :
        Journal of Bone and Mineral Research
      6. Products :
      7. Volume :
        22
      8. Issue :
        8
      9. Page Numbers :
        N/A
      10. Research Area :
        Physiology
      11. Keywords :
        FMT; OsteoSense; ProSense bone mineralization; bone turnover markers; molecular imaging; bisphosphonates; in vivo imaging
      12. Abstract :
        Abstract: FRFP binds to mineral at osteoblastic, osteoclastic, and quiescent surfaces, with accumulation likely modulated by vascular delivery. In vivo visualization and quantification of binding can be accomplished noninvasively in animal models through optical tomographic imaging.

        Introduction: The development of near-infrared optical markers as reporters of bone metabolism will be useful for early diagnosis of disease. Bisphosphonates bind differentially to osteoblastic and osteoclastic surfaces depending on choice of side-chain and dose, and fluorescently tagged bisphosphonates provide a convenient way to visualize these sites. This study examines the ability of a fluorescently labeled pamidronate imaging probe to bind to regions of bone formation and resorption in vivo.

        Materials and Methods: In vitro binding of a far-red fluorescent pamidronate (FRFP) to mineral was assessed using intact and demineralized dentine slices. In vivo, FRFP binding was studied in three models: developing neonatal mouse, bone healing after injury, and metastasis-induced osteolysis and fracture. 3D fluorescence molecular tomographic (FMT) imaging was used to visualize signal deep within the body.

        Results: FRFP binding to bone depends on the quantity of mineral present and can be liberated from the bone during decalcification. In vivo, FRFP binds to surfaces of actively forming bone, as assessed by alkaline phosphatase staining, surfaces undergoing active resorption, as noted by scalloped bone border and presence of osteoclasts, and to quiescent surfaces not involved in formation or resorption. Binding is likely modulated by vascular delivery of the imaging agent to the exposed mineral surface and total quantity of surface exposed.FMT imaging is capable of visualizing regions of bone formation because of a large volume of labeled surface, but like radiolabeled bone scans, cannot discriminate pure osteolysis caused by metastasis.

        Conclusions: FRFP may function as a local biomarker of bisphosphonate deposition to assess interplay between drug and cellular environment or may be combined with other imaging agents or fluorescent cells for the noninvasive assessment of local bone metabolism in vivo.
      13. URL :
        http://onlinelibrary.wiley.com/doi/10.1359/jbmr.070504/references?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nat%20Med&rft.atitle=Shedding%20light%20onto%20live%20molecular%20targets&rft.volume=9&rf
      14. Call Number :
        PKI @ sarah.piper @
      15. Serial :
        4530
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