Citation Details

Journal Article

Bioware; Imaging systems; PC-3M-luc; Spectroscopy, fluorescence and luminescence

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Journal Article

Animals, Ceftriaxone/therapeutic use, Cephalosporins/therapeutic use, Disease Models, Animal, Disease Susceptibility, Drosophila Proteins, Inflammation/genetics/immunology/microbiology/pathology, Listeria Infections/genetics/immunology, Listeria monocytogenes/genetics/immunology, Membrane Glycoproteins/ deficiency/genetics, Meningitis, Bacterial/ genetics/ immunology/microbiology/pathology, Mice, Mice, Inbred C57BL, Mice, Knockout, Pneumococcal Infections/genetics/immunology/microbiology/pathology, Receptors, Cell Surface/ deficiency/genetics, Streptococcus pneumoniae/ immunology, Time Factors, Toll-Like Receptor 2, Toll-Like Receptors IVIS, Xenogen, Xen10

Toll-like receptor-2 (TLR2) mediates host responses to gram-positive bacterial wall components. TLR2 function was investigated in a murine Streptococcus pneumoniae meningitis model in wild-type (wt) and TLR2-deficient (TLR2(-/-)) mice. TLR2(-/-) mice showed earlier time of death than wt mice (P<.02). Plasma interleukin-6 levels and bacterial numbers in blood and peripheral organs were similar for both strains. With ceftriaxone therapy, none of the wt but 27% of the TLR2(-/-) mice died (P<.04). Beyond 3 hours after infection, TLR2(-/-) mice had higher bacterial loads in brain than did wt mice, as assessed with luciferase-tagged S. pneumoniae by means of a Xenogen-CCD (charge-coupled device) camera. After 24 h, tumor necrosis factor activity was higher in cerebrospinal fluid of TLR2(-/-) than wt mice (P<.05) and was related to increased blood-brain barrier permeability (Evans blue staining, P<.02). In conclusion, the lack of TLR2 was associated with earlier death from meningitis, which was not due to sepsis but to reduced brain bacterial clearing, followed by increased intrathecal inflammation.

Journal Article

Animals; Bioware; Diagnostic Imaging; Fluorescent Dyes; Green Fluorescent Proteins; Luciferases; Luminescent Measurements; Luminescent Proteins; Mice; Mice, Inbred BALB C; Neoplasms; PC-3M-luc; Pneumonia

In vivo imaging of cells tagged with light-emitting probes, such as firefly luciferase or fluorescent proteins, is a powerful technology that enables a wide range of biological studies in small research animals. Reporters with emission in the red to infrared (>600 nm) are preferred due to the low absorption in tissue at these wavelengths. Modeling of photon diffusion through tissue indicates that bioluminescent cell counts as low as a few hundred can be detected subcutaneously, while approximately 10(6) cells are required to detect signals at approximately 2 cm depth in tissue. Signal-to-noise estimates show that cooled back-thinned integrating charge coupled devices (CCDs) are preferred to image-intensified CCDs for this application, mainly due to their high quantum efficiency (approximately 85%) at wavelengths >600 nm where tissue absorption is low. Instrumentation for in vivo imaging developed at Xenogen is described and several examples of images of mice with bioluminescent cells are presented.

Journal Article

Animals; Bioware; Diagnostic Imaging; Genes, Reporter; Green Fluorescent Proteins; Humans; Luciferases; Luminescent Proteins; Neoplasms; PC-3M-luc; Time Factors; Tumor Cells, Cultured

Revealing the cellular and molecular changes associated with cancer, as they occur in intact living animal models of human neoplastic disease, holds tremendous potential for understanding disease mechanisms and elucidating effective therapies. Since light is transmitted through mammalian tissues, at a low level, optical signatures conferred on tumor cells by expression of reporter genes encoding bioluminescent and fluorescent proteins can be detected externally using sensitive photon detection systems. Expression of reporter genes, such as the bioluminescent enzyme firefly luciferase (Luc) or variants of green fluorescent protein (GFP) in transformed cells, can effectively be used to reveal molecular and cellular features of neoplasia in vivo. Tumor cell growth and regression in response to various therapies have been evaluated non-invasively in living experimental animals using these reporter genes. Detection of Luc-labeled cells in vivo was extremely sensitive with signals over background from as few as 1000 human tumor cells distributed throughout the peritoneal cavity of a mouse with linear relationships between cell number and signal intensity over five logs. GFP offers the strength of high-resolution ex vivo analyses following in vivo localization of the tumor. The dynamic range of Luc detection allows the full disease course to be monitored since disease progression from small numbers of cells to extensive disease can be assessed. As such, therapies that target minimal disease as well as those designed for late stage disease can be readily evaluated in animal models. Real time spatiotemporal analyses of tumor cell growth can reveal the dynamics of neoplastic disease, and facilitate rapid optimization of effective treatment regimens. Thus, these methods improve the predictability of animal models of human disease as study groups can be followed over time, and can accelerate the development of therapeutic strategies.

Journal Article

atherosclerosis; in vivo imaging; monocytes; VivoTag; FMT; fluorescence molecular tomography

Monocytes and macrophages play active roles in atherosclerosis, a chronic inflammatory disease that is a leading cause of death in the developed world. The prevailing paradigm states that, during human atherogenesis, monocytes accumulate in the arterial intima and differentiate into macrophages, which then ingest oxidized lipoproteins, secrete a diverse array of proinflammatory mediators, and eventually become foam cells, the key constituents of a vulnerable plaque. Yet monocytes are heterogeneous. In the mouse, one subset (Ly-6Chi) promotes inflammation, expands in hypercholesterolemic conditions, and selectively gives rise to macrophages in atheromata. A different subset (Ly-6Clo) attenuates inflammation and promotes angiogenesis and granulation tissue formation in models of tissue injury, but its role in atherosclerosis is largely unknown. In the human, monocyte heterogeneity is preserved but it is still unresolved how subsets correspond functionally. The contradistinctive properties of these cells suggest commitment for specific function before infiltrating tissue. Such commitment argues for discriminate targeting of deleterious subsets while sparing host defense and repair mechanisms. In addition to advancing our understanding of atherosclerosis, the ability to target and image monocyte subsets would allow us to evaluate drugs designed to selectively inhibit monocyte subset recruitment or function, and to stratify patients at risk for developing complications such as myocardial infarction or stroke. In this review we summarize recent advances of our understanding of the behavioral heterogeneity of monocytes during disease progression and outline emerging molecular imaging approaches to address key questions in the field.