bluuebunny/crossref_metadata_2025 huggingface dataset:
A Team Observed Structured Clinical Encounter (TOSCE) for Pre-Licensure Learners in Maternity Care: A Short Report on the Development of an Assessment Tool for Collaboration
Authors: Murray-Davis Beth , Solomon Patricia , Malott Anne , Marshall Denise , Mueller Valerie , Shaw Elizabeth , Dore Kelly , Burns Sheri
Published: March 2018

Background: Despite the support for Interprofessional Education (IPE) among policymakers, educators and professional regulating bodies, the research literature is limited with respect to the evaluation of effective assessment strategies. This short report outlines the development of a Team Observed Structured Clinical Encounter (TOSCE), which brings together learners from three health professions involved in primary care obstetrics-family physicians, midwives, and obstetricians-as a strategy for assessing collaborative competencies.Methods: An interprofessional research team was brought together to develop and implement the TOSCE. The process by which the team generated TOSCE scenario stations is outlined, including the consensus-building process, based on a modified Delphi technique, to include expert input from others in the field of practice.Findings: The scenarios developed by the research team for the TOSCE are highlighted including the assessment criteria, based on the Canadian InterprofessionalHealth Collaborative's National Competency Framework.Conclusions: The TOSCE is an emerging and innovative learning tool that encourages the development of essential collaborative competencies. The process of developing a TOSCE outlined in this report offers an affordable, streamlined approach that could be used by educators in many disciplines as a summative or formative assessment strategy.
Exploring Social Media’s Potential in Interprofessional Education
Authors: Cain Jeff , Chretien Katherine
Published: March 2018

Social media applications such as Facebook, Twitter, and blogs have become part of mainstream society and are currently being used throughout health professions education. The asynchronous nature and conversational aspects of social media permit learners to collaborate with and learn from others in different fields. Interprofessional education (IPE) is a growing paradigm in health professions schools for a variety of reasons, including the desire to teach future practitioners how to communicate with each other and engage in collaborative care. Due to the interdisciplinary nature of IPE curricula, those programs must overcome numerous logistical barriers to be successful. Finding suitable times and locations for interprofessional students to meet and arranging opportunities for them to collaborate on healthcare issues are just two of the logistical impediments to IPE implementation. Fortunately, the asynchronous, conversational, and collaborative aspects of social media applications enable them to facilitate interprofessional communication and alleviate some of the time and space issues. In this article, we describe in further detail the merits of social media relevant to IPE, provide specific examples of how social media can be used to enhance aspects of IPE programs, and make a call for further research in this area.
What Does Collaborative Practice Mean Within Mental Health Care?: A Qualitative Study Exploring Understandings and Proposing a Definition.
Authors: Jones Gabrielle Margaret , Delany Toni
Published: March 2018

Background: Despite frequent appearances in service documents, the concept ofcollaborative practice is ill defined in mental health practice. The purposes of this pilot study were to gain insight into professionals’ conceptual and practical understandings of collaborative mental health practice (CMHP), to use these insights to develop a proposed definition, and to inform the development of a collaborative practice assessment tool.Methods and findings: This pilot study involved semi-structured interviews with four mental health professionals who have knowledge of a service model that endorses collaborative practice as a service principle. Thematic analysis of interview data revealed the importance of contextualized collaborative practice, a shared belief in the importance of equalized communication with clients, and concerns about the impacts of structural disincentives on collaborative practice. Using Habermas’ theory of communicative action, the findings were applied to develop a proposed definition of CMHP. The main limitations of the study relate to small sample size; however, efforts have been expended to ensure rich data were collected from all participants.Conclusion: These findings illustrate the importance of context-sensitive team formation and shared philosophical understandings regarding collaborative practice, which both provide a foundation for CMHP to improve client outcomes. Further research is required to build upon the proposed definition of CMHP, as well as the assessment tool that is suggested within the article.
Observed Interprofessional Collaboration (OIPC) During Interdisciplinary Team Meetings: Development and Validation of a Tool in a Rehabilitation Setting
Authors: Careau Emmanuelle , Vincent Claude , Swaine Bonnie R.
Published: March 2018

Background: Despite all the efforts made in the past few years, interprofessional collaboration (IPC) in clinical settings is not always optimal. In addition, there are only a few instruments that healthcare managers and practitioners can use to evaluate the quality of IPC practice. Therefore, we developed an observationbased tool to evaluate IPC interactional factors occurring during interdisciplinary team meetings, and we examined the initial validation of the tool in a rehabilitation setting.Methods and Findings: The items were developed and pre-tested iteratively by construct experts (N = 7) and non-experts (N = 4). Interrater reliability was determined between two observers, following the analysis of 30 video recordings of meetings in two rehabilitation centres involving a total of 152 participants. An observation grid (OIPC) consisting of 20 items that can be answered on a threepoint scale and demonstrating acceptable interrater reliability was developed.Conclusions: The OIPC is a tool aimed at evaluating IPC interactional factors during interdisciplinary meetings based on team performance rather than individual behaviours. It can be useful for healthcare managers and practitioners who want to evaluate the quality of IPC practices.
"Walking the Walk”: Promoting Competencies for Interprofessional Learning through Team Meetings—A Case Study
Authors: Links Matthew
Published: March 2018

Background: Interprofessional learning is a key aspect of improving team-based healthcare. Core competencies for interprofessional education (IPE) activities have recently been developed, but there is a lack of guidance as to practical application. Methods and Findings: Cancer Forum is a weekly multi-professional meeting used as the case study for this report. Power was identified as a critical issue and six questions were identified as the basis for a structured reflection on the conduct of Cancer Forum. Results were then synthesised using Habermas’ delineation of learning as instrumental, normative, communicative, dramaturgical, and emancipatory. Power was a key issue in identified obstacles to inter professional learning. Leadership emerged as a cross-cutting theme and was added as a seventh question. The emancipatory potential of interprofessional learning benefited from explicit consideration of the meeting agenda to promote competencies of sharing role knowledge, teamwork and communication. Modelling of required skills fulfils a dramaturgical and normative role. Conclusions: The structured reflection tool highlighted the relationship between power and IPE competencies. It was essential to walk the walk as well as talk. The process followed provides a practical guide for using team meetings to promote interprofessional learning competencies and thereby improving patient care.
Moving the Interprofessional Education Research Agenda Beyond the Limits of Evaluating Student Satisfaction
Authors: Lawn Sharon
Published: March 2018

Background: Much of the research on the impact of interprofessional education (IPE) interventions is hampered by a lack of focus on whether they were successfully translated to effective interprofessional practice (IPP).Methods and Findings: This article reports the outcomes of a think tank of Australian IPE researchers who articulated these gaps and brainstormed types of research and research questions needed to help address these gaps. A social constructivist theoretical approach was proposed, including more ethnographic and longitudinal investigation.Conclusions: A greater focus on theory is needed to understand the underlying processes involved in IPE, IPP, and the transition between them. This will involve researchers employing more qualitative and mixed-method approaches in addition to the quantitative methods that appear to dominate this field, currently.
Interprofessional Education: Graduate Students’ Perspectives
Authors: Leflore Judy L. , Bond Mary Lou , Anderson Mindi , Baxley Susan , Díaz Desiree A.
Published: March 2018

Background: This program evaluation used qualitative methodology to describestudents’ expectations, concerns, needed supports, and experiences in a yearlongInterprofessional Education program.Methods and Findings: Focus groups were used to obtain the views of nurse practitionerand Master of social work students. Students participated in focus groups atthe program beginning and completion. Interprofessional education competencies,expectations, and concerns were examined. Results showed that at the beginning,students indicated a desire to understand the other’s professional role. They alsoexpressed concerns. During the post-program interviews, students indicated adesire to have had more classes and work together in clinical practice. Limitationsincluded a lack of participation of all students in the final focus groups.Conclusions: Student input in a program is essential. Further research is needed.Keywords: Interprofessional education (IPE); Qualitative research; Student evaluation;Graduate education
Highly thermally resistant hydrophobic poly(vinyl alcohol)-silica hybrid nanofibers
Authors: Hulusi Ugur , Oktay Burcu , Gungor Atilla , Kayaman-Apohan Nilhan
Published: March 2018

In this paper, the preparation of hydrophobic and crosslinked poly- (vinyl alcohol)/silica organic?inorganic hybrid nanofibers via the sol?gel electrospinning method is reported. Silica was produced through the acetic acid catalyzed reaction of a silica precursor consisting of dimethyldimethoxysilane (DMDMOS), methyltrimethoxysilane (MTMS), tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane (FAS1313; Dynasylan? F 8261) and phenyltrimethoxysilane (PTMS; Dynasylan? 9165) in a 2-propanol?water mixture. Hybrid nanofibers were obtained by electrospinning the silica precursor and an aqueous PVA solution. Chemical, structural, thermal and surface analyses were conducted by Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and water contact angle (WCA) methods, respectively. The obtained hybrid nanofibers were insoluble in aqueous solution. SEM images displayed that highly crosslinked and porous structures were obtained and the average fiber diameters of poly(vinyl alcohol) (PVA)/silica nanocomposites were around 70 nm. A nanofiber surface with a water contact angle of 130? was achieved.
Practical Vessel Imaging by Computed Tomography in Live Transgenic Mouse Models for Human Tumors
Authors: Kindlmann Gordon L. , Weinstein David M. , Jones Greg M. , Johnson Christopher R. , Capecchi Mario R. , Keller Charles
Published: March 2018

Contrast-enhanced small-animal computed tomography is an economical and highly quantitative tool for serially examining tumor development in situ, for analyzing the network of blood vessels that nourish them, and for following the response of tumors to preclinical therapeutic intervention(s). We present practical considerations for visualizing the vascular network of transgenic mouse tumors. Using a long-acting iodinated triglyceride blood-pool contrast agent, we present optimized scanner acquisition parameters and volume-rendering techniques for examining the intermediate and large vessels of complex spontaneous tumors (e.g., alveolar rhabdomyosarcomas) in transgenic mice. Our findings indicate that multiple-frame, 360–720 view acquisitions were mandatory for clarifying bone and soft tissue from vessel contrast. This finding was consistent in visualizations using a one-dimensional transfer function where voxel color and opacity was assigned in proportion to CT value and a two-dimensional transfer function where voxel color and opacity was assigned in proportion to CT value and gradient magnitude. This study lays a groundwork for the qualitative and quantitative assessment of anti-angiogenesis preclinical studies using transgenic mice.
Microimaging Characterization of a B16-F10 Melanoma Metastasis Mouse Model
Authors: Winkelmann Christopher T. , Figueroa Said Daibes , Rold Tammy L. , Volkert Wynn A. , Hoffman Timothy J.
Published: March 2018

Metastatic mouse models of melanoma have been characterized by gross necropsy examination, histopathology, and optical imaging. To determine if the time progression, extent, and metabolism of melanoma metastases could be monitored noninvasively, serial micro-CT and small-animal PET imaging studies were performed by using a mouse model of melanoma. Juvenile female C57BL/6 mice were injected intravenously with syngenic B16-F10 melanoma cells. Serial micro-CT imaging studies were performed on anesthetized mice. Mice were necropsied at the development of adverse clinical signs or at postinjection Day 30, and tissues were collected for histopathology. In a separate study of four mice, tumor viability was assessed with 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) and studied by using small-animal PET imaging. A total of 59% of the mice developed metastatic tumors. Micro-CT image analysis was able to identify and follow up to 36% of metastatic lesions. Examples of metastatic lesions identified and followed up by micro-CT imaging included a lung metastasis, mandibular metastasis, subcutaneous metastasis, and tibial/femoral metastasis. Micro-CT and small-animal PET fusion imaging successfully correlated anatomic localization of glucose metabolism of the metastatic tumors. Micro-CT and small-animal PET imaging were found to be highly effective in detection and characterization of lesions produced by this metastatic melanoma model.
Imaging of Proteolytic Activity Using a Conditional Cell Surface Receptor
Authors: Bhojani Mahaveer Swaroop , Hamstra Daniel A. , Chang Daniel C. , Coppola Julia M. , Khan Amjad P. , Reddy G. Ramachandra , Ross Brian D. , Rehemtulla Alnawaz
Published: March 2018

Programmed cell death (apoptosis) is a ubiquitous means utilized by multicellular organisms for elimination of unwanted cells during development and homeostasis. Dysregulated apoptosis is implicated in an array of clinical disorders including cancer, autoimmune diseases, neurodegenerative disorders, and ischemia. During programmed cell death, a series of proteases, known as caspases, with different specificities play crucial roles in the apoptotic process. Caspase-3, a group II cysteine aspartate protease, recognizes and cleaves substrates harboring the amino acid sequence aspartic acid–glutamic acid–valine–aspartic acid (DEVD), and it plays an important role in the terminal phase of apoptosis. Here we report the development of a novel imaging platform for sensing the activation of cellular proteases. A recombinant chimeric protein was constructed, composed of a cell-surface-targeted single-chain antibody (sFv) fused to a Golgi retention signal. The DEVD tetrapeptide sequence was included between the single-chain antibody and the Golgi retention signal as a caspase-3 protease cleavage site. When expressed in cultured cells this fusion protein was localized to Golgi bodies and was not detected on the cell surface. Induction of apoptosis resulted in cleavage of the fusion protein releasing the single-chain antibody from the Golgi retention signal in a caspase-dependent manner. As a result, in cells undergoing apoptosis the single-chain antibody was visualized at the cell surface by immunofluorescence microscopy. The expression of sFv on the surface of cells in a protease-dependent manner provides a unique opportunity for real-time imaging through the use of targeted nanoparticles. This methodology may provide for a multimodal noninvasive real-time imaging of apoptosis and a new opportunity for high-throughput screening of cell-death-modulating therapeutic agents.
Synthesis of Poly[APMA]-DOTA-64Cu Conjugates for Interventional Radionuclide Therapy of Prostate Cancer: Assessment of Intratumoral Retention by Micro–Positron Emission Tomography
Authors: Yuan Jianchao , You Yezi , Lu Xin , Muzik Otto , Oupicky David , Peng Fangyu
Published: March 2018

To develop new radiopharmaceuticals for interventional radionuclide therapy of locally recurrent prostate cancer, poly[ N-(3-aminopropyl)methacrylamide] [poly(APMA)] polymers were synthesized by free radical precipitation polymerization in acetonedimethylsulfoxide using N,N‘-azobis(isobutyronitrile) as the initiator. The polymers were characterized with nuclear magnetic resonance, size exclusion chromatography, and dynamic light scattering ( Mn 5 2.40 × 104, Mw/ Mn = 1.87). Subsequently, poly[APMA] was coupled with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride as an activator, followed by conjugation with 64Cu radionuclide. Prolonged retention of poly[APMA]-DOTA-64Cu conjugates within the tumor tissues was demonstrated by micro–positron emission tomography at 24 hours following intra-tumoral injection of the conjugates to human prostate xenografts in mice. The data suggest that the poly[APMA]-DOTA-64Cu conjugates might be useful for interventional radionuclide therapy of locally recurrent prostate cancer in humans.
Red-Shifted Aequorin-Based Bioluminescent Reporters for in Vivo Imaging of Ca2+ Signaling
Authors: Curie Thomas , Rogers Kelly L. , Colasante Cesare , BrûClet Philippe
Published: March 2018

Real-time visualization of calcium (Ca2+) dynamics in the whole animal will enable important advances in understanding the complexities of cellular function. The genetically encoded bioluminescent Ca2+ reporter green fluorescent protein–aequorin (GA) allows noninvasive detection of intracellular Ca2+ signaling in freely moving mice. However, the emission spectrum of GA is not optimal for detection of activity from deep tissues in the whole animal. To overcome this limitation, two new reporter genes were constructed by fusing the yellow fluorescent protein (Venus) and the monomeric red fluorescent protein (mRFP1) to aequorin. Transfer of aequorin chemiluminescence energy to Venus (VA) is highly efficient and produces a 58 nm red shift in the peak emission spectrum of aequorin. This substantially improves photon transmission through tissue, such as the skin and thoracic cage. Although the Ca2+-induced bioluminescence spectrum of mRFP1-aequorin (RA) is similar to that of aequorin, there is also a small peak above 600 nm corresponding to the peak emission of mRFP1. Small amounts of energy transfer between aequorin and mRFP1 yield an emission spectrum with the highest percentage of total light above 600 nm compared with GA and VA. Accordingly, RA is also detected with higher sensitivity from brain areas. VA and RA will therefore improve optical access to Ca2+ signaling events in deeper tissues, such as the heart and brain, and offer insight for engineering new hybrid molecules.
Bioluminescence Imaging of Period1 Gene Expression in Utero
Authors: Saxena Meera T. , Aton Sara J. , Hildebolt Charles , Prior Julie L. , Abraham Ute , Piwnica-Worms David , Herzog Erik D.
Published: March 2018

The use of real-time reporters has accelerated our understanding of gene expression in vivo. This study examined the feasibility of a luciferase-based reporter to image spatiotemporal changes in fetal gene expression in utero. We chose to monitor Period1 ( Per1) because it is expressed broadly in the body and plays a role in circadian rhythmicity. Using rats carrying a Per1::luc transgene, we repetitively imaged fetuses in utero throughout gestation. We found that bioluminescence was specific to transgenic pups, increased dramatically on embryonic day 10 (10 days after successful mating), and continued to increase logarithmically until birth. Diurnal fluctuations in Per1 expression were apparent several days prior to birth. These results demonstrate the feasibility of in utero imaging of mammalian gene expression, tracking of fetal gene expression from the same litter, and early detection of mammalian clock gene expression. We conclude that luciferase-based reporters can provide a sensitive, noninvasive measure of in utero gene expression.
Magnetic Targeting of Rhodamine-Labeled Superparamagnetic Liposomes to Solid Tumors: In Vivo Tracking by Fibered Confocal Fluorescence Microscopy
Authors: Martina Marie-Sophie , Fortin Jean-Paul , Fournier Laure , Ménager Christine , Gazeau Florence , Clément Olivier , Lesieur Sylviane
Published: March 2018

Polyethylene glycol (PEG)ylated and rhodamine-labeled liposomes loaded with maghemite nanocrystals provide a novel nanoscaled hybrid system for magnetic targeting to solid tumors in possible combination with double in vivo imaging by fluorescence microscopy and magnetic resonance imaging (MRI). Human prostate adenocarcinoma tumors implanted in mice were used as a system model. A magnetic field gradient was produced at the tumor level by external apposition of a magnet. Noninvasive fibered confocal fluorescence microscopy was successfully used to track the liposomes in vivo within organs and tumor blood vessels. Active targeting to the magnet-exposed tumors was clearly shown, in agreement with previous MRI studies. The liposomes were driven and accumulated within the microvasculature through a process that preserved vesicle structure and content.
Color Transformation and Fluorescence of Prussian Blue–Positive Cells: Implications for Histologic Verification of Cells Labeled with Superparamagnetic Iron Oxide Nanoparticles
Authors: Frank Joseph A. , Kalish Heather , Jordan E. Kay , Anderson Stasia A. , Pawelczyk Edyta , Arbab Ali S.
Published: March 2018

Superparamagnetic iron oxide (SPIO) nanoparticles, either modified or in combination with other macromolecules, are being used for magnetic labeling of stem cells and other cells to monitor cell trafficking by magnetic resonance imaging (MRI) in experimental models. The correlation of histology to MRI depends on the ability to detect SPIO-labeled cells using Prussian blue (PB) stain and fluorescent tags to cell surface markers. Exposure of PB-positive sections to ultraviolet light at a wavelength of 365 nm commonly used fluorescence microscopy can result in color transformation of PB-positive material from blue to brown. Although the PB color transformation is primarily an artifact that may occur during fluorescence microscopy, the transformation can be manipulated using imaging process software for the detection of low levels of iron labeled cells in tissues samples
Multitracer Positron Emission Tomographic Imaging of Exogenous Gene Expression Mediated by a Universal Herpes Simplex Virus 1 Amplicon Vector
Authors: Kummer Christiane , Winkeler Alexandra , Dittmar Claus , Bauer Bernd , Rueger Maria Adele , Rueckriem Benedikt , Heneka Michael T. , Vollmar Stefan , Wienhard Klaus , Fraefel Cornel , Heiss Wolf-Dieter , Jacobs Andreas H.
Published: March 2018

To develop efficient and safe gene therapy approaches, the herpes simplex virus type 1 thymidine kinase gene (HSV-1- tk) has been shown to function as a marker gene for the direct noninvasive in vivo localization of thymidine kinase (TK) expression by positron emission tomography (PET) using radiolabeled nucleoside analogues as specific TK substrates. Moreover, the gene encoding dopamine type 2 receptor ( d2r) could be used as a PET marker gene using specific radiolabeled receptor binding compounds. Here we describe the quantitative colocalization of d2r and HSV-1- tk gene expression mediated from a universal HSV-1 amplicon vector in a subcutaneous human Gli36dEGFR glioma model by PET. The HSV-1 amplicon vector was constructed using a bicistronic gene cassette to contain (1) the d2r80A mutant, which is able to bind its ligand racloprid but unable to activate downstream signal transduction pathways, and (2) the tk39 mutant with enhanced enzymatic activity toward guanosine analogues fused to the green fluorescent protein gene ( tk39gfp) serving as a marker gene in cell culture. After infection of human Gli36dEGFR glioma cells with the HSV- d2r80AIRES tk39gfp (HSV-DITG) amplicon vector in cell culture, D2 receptor expression and its targeting to the cell surface were determined by Western blotting and immunolabeling. Vector application in vivo served for quantitative colocalization of d2r80A- and tk39gfp-derived PET signals employing the specific D2 receptor binding compound [11C]racloprid and the specific TK39 substrate 9-(4-[18F]fluoro-3-hydroxymethylbutyl)guanine. Our results demonstrate that for the range of gene expression studied in vivo, both enzymatic and receptor binding assays give comparable quantitative information on the level of vector-mediated gene expression in vivo. The d2r80A in combination with a specific binding compound passing the intact blood-brain barrier might be an alternative marker gene for the noninvasive assessment of vector-mediated gene expression in the brain using PET.
In Vivo Resolution of Multiexponential Decays of Multiple Near-Infrared Molecular Probes by Fluorescence Lifetime-Gated Whole-Body Time-Resolved Diffuse Optical Imaging
Authors: Akers Walter , Lesage Frederic , Holten Dewey , Achilefu Samuel
Published: March 2018

The biodistribution of two near-infrared fluorescent agents was assessed in vivo by time-resolved diffuse optical imaging. Bacteriochlorophyll a (BC) and cypate-glysine-arginine-aspartic acid-serine-proline-lysine-OH (Cyp-GRD) were administered separately or combined to mice with subcutaneous xenografts of human breast adenocarcinoma and slow-release estradiol pellets for improved tumor growth. The same excitation (780 nm) and emission (830 nm) wavelengths were used to image the distinct fluorescence lifetime distribution of the fluorescent molecular probes in the mouse cancer model. Fluorescence intensity and lifetime maps were reconstructed after raster-scanning whole-body regions of interest by time-correlated single-photon counting. Each captured temporal point-spread function (TPSF) was deconvolved using both a single and a multiexponental decay model to best determine the measured fluorescence lifetimes. The relative signal from each fluorophore was estimated for any region of interest included in the scanned area. Deconvolution of the individual TPSFs from whole-body fluorescence intensity scans provided corresponding lifetime images for comparing individual component biodistribution. In vivo fluorescence lifetimes were determined to be 0.8 ns (Cyp-GRD) and 2 ns (BC). This study demonstrates that the relative biodistribution of individual fluorophores with similar spectral characteristics can be compartmentalized by using the time-domain fluorescence lifetime gating method.
Improved in Vivo Whole-Animal Detection Limits of Green Fluorescent Protein–Expressing Tumor Lines by Spectral Fluorescence Imaging
Authors: Tam Jenny M. , Upadhyay Rabi , Pittet Mikael J. , Weissleder Ralph , Mahmood Umar
Published: March 2018

Green fluorescent protein (GFP) has been used for cell tracking and imaging gene expression in superficial or surgically exposed structures. However, in vivo murine imaging is often limited by several factors, including scatter and attenuation with depth and overlapping autofluorescence. The autofluorescence signals have spectral profiles that are markedly different from the GFP emission spectral profile. The use of spectral imaging allows separation and quantitation of these contributions to the total fluorescence signal seen in vivo by weighting known pure component profiles. Separation of relative GFP and autofluorescence signals is not readily possible using epifluorescent continuous-wave single excitation and emission bandpass imaging (EFI). To evaluate detection thresholds using these two methods, nude mice were subcutaneously injected with a series of GFP-expressing cells. For EFI, optimized excitation and emission bandpass filters were used. Owing to the ability to separate autofluorescence contributions from the emission signal using spectral imaging compared with the mixed contributions of GFP and autofluorescence in the emission signal recorded by the EFI system, we achieved a 300-fold improvement in the cellular detection limit. The detection limit was 3 × 103 cells for spectral imaging versus 1 × 106 cells for EFI. Despite contributions to image stacks from autofluorescence, a 100-fold dynamic range of cell number in the same image was readily visualized. Finally, spectral imaging was able to separate signal interference of red fluorescent protein from GFP images and vice versa. These findings demonstrate the utility of the approach in detecting low levels of multiple fluorescent markers for whole-animal in vivo applications.
In Vivo Bioluminescence Visualization of Antitumor Effects by Human MUC1 Vaccination
Authors: Jeon Yong Hyun , Choi Yun , Kim Hyun Joo , Kang Joo Hyun , Kim Chul Woo , Jeong Jae Min , Lee Dong Soo , Chung June-Key
Published: March 2018

Recently, the use of a cancer deoxyribonucleic acid (DNA) vaccine encoding tumor-associated antigens has emerged as an immunotherapeutic strategy. In this study, we monitored tumor growth inhibition by pcDNA3-hMUC1 immunization in mice using optical imaging. To determine the anti-hMUC1-associated immune response generated by pcDNA3.1 or pcDNA3-hMUC1, we determined the concentration of interferon-γ (IFN-γ) protein and CD8+IFN-γ cell numbers among lymphocytes from the draining lymph nodes of mice immunized with pcDNA3.1 or pcDNA3-hMUC1. After subcutaneously injecting CT26/hMUC1-F luc into mice immunized with pcDNA3-hMUC1, we monitored in vivo tumor growth inhibition using an optical imaging method. The concentration of IFN-γ protein in pcDNA3-hMUC1 was higher than that of the pcDNA3.1 group (2.7 ⩽ 0.08 ng/mL and 1.6 ± 0.07 ng/mL, respectively, p < .001. The number of hMUC1-associated CD8+IFN-γ cells in pcDNA3-hMUC1-immunized animals was 30-fold higher than in the pcDNA3.1 group. Bioluminescent images showed tumor growth inhibition in pcDNA3-hMUC1 immunized animals up to 25 days after immunization. A good correlation ( r2 = .9076: pcDNA3/hMUC1 group; r2 = .7428: pcDNA3.1 group) was observed between bioluminescence signals and tumor weights in two mice in each group. We conclude that optical bioluminescent imaging offers a useful means of monitoring the antitumor effects of cancer DNA immunization in living animals.
Bioluminescence Imaging of Vascular Endothelial Growth Factor Promoter Activity in Murine Mammary Tumorigenesis
Authors: Faley Shannon L. , Takahashi Keiko , Crooke Cornelia E. , Beckham Joshua T. , Tomemori Takuya , Shappell Scott B. , Jansen E. Duco , Takahashi Takamune
Published: March 2018

Vascular endothelial growth factor (VEGF) is a major inducer of angiogenesis. We generated a transgenic reporter mouse, VEGF-GL, in which an enhanced green fluorescent protein-luciferase fusion protein is expressed under the control of a human VEGF-A promoter. The VEGF-GL mouse exhibited intense bioluminescence throughout the body at 1 week of age. The signals rapidly declined to a relatively low level as the mice grew. The adult VEGF-GL mouse showed restricted bioluminescence to the areas undergoing wound healing. In contrast, the VEGF-GL mice, which were crossed with mouse mammary tumor virus-polyoma virus middle T antigen transgenic mammary tumor mice, exhibited prominent bioluminescence in the tumors, correlating with VEGF transcription. Tumor bioluminescence was observed in the bigenic mice as early as 8 weeks, before tumors were palpable, and the signals increased with tumor growth. In conclusion, the VEGF-GL mouse permits longitudinal and quantitative assessment of VEGF promoter activity in vivo. The model should facilitate understanding of the molecular controls and pathways that regulate VEGF transcription in vivo.
In Vivo Time Domain Optical Imaging of Renal Ischemia-Reperfusion Injury: Discrimination Based on Fluorescence Lifetime
Authors: Abulrob Abedelnasser , Brunette Eric , Slinn Jacqueline , Baumann Ewa , Stanimirovic Danica
Published: March 2018

Fluorescence lifetime is an intrinsic parameter of the fluorescent probe, independent of the probe concentration but sensitive to changes in the surrounding microenvironment. Therefore, fluorescence lifetime imaging could potentially be applied to in vivo diagnostic assessment of changes in the tissue microenvironment caused by disease, such as ischemia. The aim of this study was to evaluate the utility of noninvasive fluorescence lifetime imaging in distinguishing between normal and ischemic kidney tissue in vivo. Mice were subjected to 60-minute unilateral kidney ischemia followed by 6-hour reperfusion. Animals were then injected with the near-infrared fluorescence probe Cy5.5 or saline and imaged using a time-domain small-animal optical imaging system. Both fluorescence intensity and lifetime were acquired. The fluorescence intensity of Cy5.5 was clearly reduced in the ischemic compared with the contralateral kidney, and the fluorescence lifetime of Cy5.5 was not detected in the ischemic kidney, suggesting reduced kidney clearance. Interestingly, the two-component lifetime analysis of endogenous fluorescence at 700 nm distinguished renal ischemia in vivo without the need for Cy5.5 injection for contrast enhancement. The average fluorescence lifetime of endogenous tissue fluorophores was a sensitive indicator of kidney ischemia ex vivo. The study suggests that fluorescence lifetime analysis of endogenous tissue fluorophores could be used to discriminate ischemic or necrotic tissues by noninvasive in vivo or ex vivo organ imaging.
Radiolabeling Rhesus Monkey CD34+ Hematopoietic and Mesenchymal Stem Cells with 64Cu-Pyruvaldehyde-Bis(N4-Methylthiosemicarbazone) for MicroPET Imaging
Authors: Huang Joanne , Lee C. Chang I. , Sutcliffe Julie L. , Cherry Simon R. , Tarantal Alice F.
Published: March 2018

Noninvasive positron emission tomography (PET) provides a potential method for in vivo tracking of radiolabeled cells. The goal of this study was to assess the potential toxicity of 64Cu-pyruvaldehyde-bis(N4-methylthiosemicarbazone) (PTSM) on rhesus monkey CD34+ hematopoietic and mesenchymal stem cells in vitro in preparation for developing imaging protocols posttransplantation. CD34+ hematopoietic cells were radiolabeled with 0 to 40 μCi/mL 64Cu-PTSM and viability and colony formation were assessed. Rhesus monkey mesenchymal stem cells (rhMSCs) were placed in culture postradiolabeling for assessments of growth and differentiation toward adipogenic, osteogenic, and chondrogenic lineages. The results indicated that CD34+ cells radiolabeled with 20 μCi/mL and rhMSCs radiolabeled with 10 μCi/mL 64Cu-PTSM did not result in adverse effects on growth or differentiation. Nonradioactive copper was also evaluated and showed that the presence of copper was not harmful to the cells. CD34+ cells and rhMSCs radiolabeled with the optimized concentrations of 20 and 10 μCi/mL, respectively, were also assessed using the microPET scanner. Studies showed that a minimum of 2.50 × 104 CD34+ cells (1.1 pCi/cell) and 6.25 × 103 rhMSCs (4.4 pCi/cell) could be detected. These studies indicate that CD34+ hematopoietic cells and rhMSCs can be safely radiolabeled with 64Cu-PTSM without adverse cellular effects.
Optical Imaging of Matrix Metalloproteinase-7 Activity in Vivo Using a Proteolytic Nanobeacon
Authors: Scherer Randy L. , VanSaun Michael N. , McIntyre J. Oliver , Matrisian Lynn M.
Published: March 2018

Matrix metalloproteinases (MMPs) are extracellular proteolytic enzymes involved in tumor progression. We present the in vivo detection and quantitation of MMP7 activity using a specific near-infrared polymer-based proteolytic beacon, PB-M7NIR. PB-M7NIR is a pegylated polyamidoamine PAMAM-Generation 4 dendrimer core covalently coupled to a Cy5.5-labeled peptide representing a selective substrate that monitors MMP7 activity (sensor) and AF750 as an internal reference to monitor relative substrate concentration (reference). In vivo imaging of tumors expressing MMP7 had a median sensor to reference ratio 2.2-fold higher than a that of a bilateral control tumor. Ex vivo imaging of intestines of multiple intestinal neoplasia (APCMin) mice injected systemically with PB-M7NIR revealed a sixfold increase in the sensor to reference ratio in the adenomas of APCMin mice compared with control intestinal tissue or adenomas from MMP7-null Min mice. PB-M7NIR detected tumor sizes as small as 0.01 cm 2 , and the sensor to reference ratio was independent of tumor size. Histologic sectioning of xenograft tumors localized the proteolytic signal to the extracellular matrix; MMP7-overexpressing tumors displayed an approximately 300-fold enhancement in the sensor to reference ratio compared with nonexpressing tumor cells. In APCMin adenomas, the proteolytic signal colocalized with the endogenously expressed MMP7 protein, with sensor to reference ratios approximately sixfold greater than that of normal intestinal epithelium. PB-M7NIR provides a useful reagent for the in vivo and ex vivo quantitation and localization of MMP-selective proteolytic activity.
Molecular Imaging of Hypoxia-Inducible Factor 1α and von Hippel-Lindau Interaction in Mice
Authors: Choi Clara Y.H. , Chan Denise A. , Paulmurugan Ramasamy , Sutphin Patrick D. , Le Quynh-Thu , Koong Albert C. , Zundel Wayne , Gambhir Sanjiv S. , Giaccia Amato J.
Published: March 2018

Tumor hypoxia plays a crucial role in tumorigenesis. Under hypoxia, hypoxia-inducible factor 1α (HIF-1α) regulates activation of genes promoting malignant progression. Under normoxia, HIF-1α is hydroxylated on prolines 402 and 564 and is targeted for ubiquitin-mediated degradation by interacting with the von Hippel-Lindau protein complex (pVHL). We have developed a novel method of studying the interaction between HIF-1α and pVHL using the split firefly luciferase complementation-based bioluminescence system in which HIF-1α and pVHL are fused to amino-terminal and carboxy-terminal fragments of the luciferase, respectively. We demonstrate that hydroxylation-dependent interaction between the HIF-1α and pVHL leads to complementation of the two luciferase fragments, resulting in bioluminescence in vitro and in vivo. Complementation-based bioluminescence is diminished when mutant pVHLs with decreased affinity for binding HIF-1α are used. This method represents a new approach for studying interaction of proteins involved in the regulation of protein degradation.
Radiosynthesis and Evaluation of 5-[125I]Iodoindol-3-yl-β-d-Galactopyranoside as a β-Galactosidase Imaging Radioligand
Authors: Van Dort Marcian E. , Lee Kuei C. , Hamilton Christin A. , Rehemtulla Alnawaz , Ross Brian D.
Published: March 2018

The synthesis and investigation of 5-[125I]iodoindol-3-yl-β-d-galactopyranoside ([125I]IBDG) as a radioligand for single-photon emission computed tomography (SPECT) imaging of β-galactosidase expression are described. No-carrier-added [125I]IBDG was synthesized by a radioiododestannylation approach in > 75% overall radiochemical yield and > 99% radiochemical purity. [125I]IBDG was evaluated as a substrate using β-galactosidase-expressing (D54L) and nonexpressing (D54) human glioma cell lines. A 24-hour incubation of this substrate with cultured cells revealed a 6.5-fold greater intracellular trapping of radioactivity in D54L cells compared with D54 cells. Systemic delivery of [125I]IBDG in nude mice bearing D54L tumors failed to show significant trapping of radioactivity within these tumors by SPECT imaging. In contrast, intratumoral injection of the substrate resulted in efficient trapping of radioactivity in D54L tumors but not D54 tumors, resulting in clear SPECT visualization of the former tumor. Based on dynamic SPECT imaging and blood metabolite analysis, we conclude that although [125I]IBDG is an efficient in vivo substrate for β-galactosidase, its rapid renal clearance hampers its intratumoral availability on systemic administration.
In Vivo Optical Imaging of Neurogenesis: Watching New Neurons in the Intact Brain
Authors: Couillard-Despres Sebastien , Finkl Rudolf , Winner Beate , Ploetz Sonja , Wiedermann Dirk , Aigner Robert , Bogdahn Ulrich , Winkler Juergen , Hoehn Mathias , Aigner Ludwig
Published: March 2018

Adult neurogenesis is a highly dynamic process modulated by several pathologic and environmental factors, as well as by various compounds. So far, available techniques to study neurogenesis are lengthy and personnel and cost intensive. We developed a new tool based on the doublecortin promoter driving the expression of the luciferase reporter gene (DCX-promo-luciferase) in transgenic mice to perform in vivo imaging of neurogenesis. Indeed, the DCX-promo-luciferase mice allowed optical in vivo imaging of the onset of and increase in neurogenesis in developing fetal brains, as well as imaging of neurogenesis in the intact adult mouse central nervous system. Moreover, the capacity to specifically detect a small number of migrating neuronal precursors in vivo after transplantation is for the first time feasible using this DCX-promo-luciferase transgenic tool. The present imaging approach offers several crucial advantages over methods currently available, such as bromodeoxyuridine incorporation or labeling using iron oxide nanoparticles. Hence, it allows longitudinal study of neurogenesis in intact animals without the requirement of cellular prelabeling. Moreover, it guarantees that detection is specific for neuronal precursors and restricted to viable cells. Hence, our DCX-promo-luciferase transgenic model constitutes an effective tool that answers the pressing need for rapid investigation of the impact on neurogenesis of a large number of candidate compounds waiting to be tested.
Lipoprotein Nanoplatform for Targeted Delivery of Diagnostic and Therapeutic Agents
Authors: Glickson Jerry D. , Lund-Katz Sissel , Zhou Rong , Choi Hoon , Chen I-Wei , Li Hui , Corbin Ian , Popov Anatoliy V. , Cao Weiguo , Song Liping , Qi Chenze , Marotta Diane , Nelson David S. , Chen Juan , Chance Britton , Zheng Gang
Published: March 2018

Low-density lipoprotein (LDL) provides a highly versatile natural nanoplatform for delivery of visible or near-infrared fluorescent optical and magnetic resonance imaging (MRI) contrast agents and photodynamic therapy and chemotherapeutic agents to normal and neoplastic cells that overexpress low-density lipoprotein receptors (LDLRs). Extension to other lipoproteins ranging in diameter from about 10 nm (high-density lipoprotein [HDL]) to over a micron (chylomicrons) is feasible. Loading of contrast or therapeutic agents onto or into these particles has been achieved by protein loading (covalent attachment to protein side chains), surface loading (intercalation into the phospholipid monolayer), and core loading (extraction and reconstitution of the triglyceride/cholesterol ester core). Core and surface loading of LDL have been used for delivery of optical imaging agents to tumor cells in vivo and in culture. Surface loading was used for delivery of gadolinium-bis-stearylamide contrast agents for in vivo MRI detection in tumor-bearing mice. Chlorin and phthalocyanine near-infrared photodynamic therapy agents (≤ 400/LDL) have been attached by core loading. Protein loading was used to reroute the LDL from its natural receptor (LDLR) to folate receptors and could be used to target other receptors. A semisynthetic nanoparticle has been constructed by coating magnetite iron oxide nanoparticles with carboxylated cholesterol and overlaying a monolayer of phospholipid to which apolipoprotein A1 or E was adsorbed for targeting HDL or adsorbing synthetic amphipathic helical peptides ltargeting LDL or folate receptors. These particles can be used for in situ loading of magnetite into cells for MRI-monitored cell tracking or gene expression.
RGD-Human Serum Albumin Conjugates as Efficient Tumor Targeting Probes
Authors: Chen Kai , Xie Jin , Chen Xiaoyuan
Published: March 2018

Cyclic arginine-glycine-aspartate (RGD) peptides and their derivatives have been intensively studied as tumor targeting probes. One major drawback, however, is their short blood circulation half-lives, which greatly compromises their targeting efficacy. To address this issue, a cyclic peptide, c(RGDyK), and an organic dye (IRDye800 or Cy5.5) were covalently conjugated onto human serum albumin (HSA). The conjugates were subjected to in vitro cell staining, in vivo near-infrared fluorescence (NIRF) imaging, ex vivo NIRF imaging, and histologic studies to evaluate their feasibility as tumor imaging probes. As a control, RAD peptide was also coupled with HSA and labeled with IRDye800 for in vivo imaging. The HSA-RGD-IRDye800 exhibited integrin αvβ3-specific binding in cell staining experiment. In vivo NIRF imaging showed higher tumor accumulation and tumor to background contrast of HSA-RGD-IRDye800 over RGD-IRDye800. The integrin specificity of HSA-RGD-IRDye800 is confirmed by both successful inhibition of tumor uptake in the presence of c(RGDyK) and the inability to accumulate in integrin-positive tumors by RAD-HSA-IRDye800. Histologic examination revealed initial tumor vascular binding and eventually both tumor vasculature and tumor cell integrin binding in vivo. In summary, we successfully developed an RGD-based protein conjugate with prolonged circulation half-life for NIRF imaging of tumor integrin αvβ3 expression. The success of this study may be generalizable for other peptide-based probes to be conjugated with HSA for prolonged tumor contrast and improved pharmacokinetics.