Citation Details

Journal Article

Anti-Infective Agents; Biofilms; Dental Pulp Cavity; Dental Pulp Diseases; Endodontics; Humans; Luminescence; Photochemotherapy; Polyethyleneimine; Porphyrins; Proteus Infections; Proteus mirabilis; Pseudomonas aeruginosa; Pseudomonas Infections; Xen5; Xen44

BACKGROUND AND OBJECTIVE To compare the effectiveness of antimicrobial photodynamic therapy (PDT), standard endodontic treatment and the combined treatment to eliminate bacterial biofilms present in infected root canals. STUDY DESIGN/MATERIALS AND METHODS Ten single-rooted freshly extracted human teeth were inoculated with stable bioluminescent Gram-negative bacteria, Proteus mirabilis and Pseudomonas aeruginosa to form 3-day biofilms in prepared root canals. Bioluminescence imaging was used to serially quantify bacterial burdens. PDT employed a conjugate between polyethylenimine and chlorin(e6) as the photosensitizer (PS) and 660-nm diode laser light delivered into the root canal via a 200-micro fiber, and this was compared and combined with standard endodontic treatment using mechanical debridement and antiseptic irrigation. RESULTS Endodontic therapy alone reduced bacterial bioluminescence by 90% while PDT alone reduced bioluminescence by 95%. The combination reduced bioluminescence by >98%, and importantly the bacterial regrowth observed 24 hours after treatment was much less for the combination (P<0.0005) than for either single treatment. CONCLUSIONS Bioluminescence imaging is an efficient way to monitor endodontic therapy. Antimicrobial PDT may have a role to play in optimized endodontic therapy.

Journal Article

Animals; Cattle; Escherichia coli; Female; Genitalia, Female; Optical Phenomena; Photons; Xen14

The objectives of this study were to (1) characterize the photonic properties of Escherichia coli-Xen14 and (2) conduct photonic imaging of E. coli-Xen14 within bovine reproductive tract segments (RTS) ex vivo (Bos indicus). E. coli-Xen14 was grown for 24h in Luria Bertani medium (LB), with or without kanamycin (KAN). Every 24h, for an 8-d interval, inoculums were imaged and photonic emissions (PE) collected. Inoculums were subcultured and plated daily to determine the colony forming units (CFU) and ratio of photon emitters to nonemitters. In the second objective, abattoir-derived bovine reproductive tracts (n=9) were separated into posterior and anterior vagina, cervix, uterine body, and uterine horns. Two concentrations (3.2x10(8) and 3.2x10(6) CFU/200microL for relative [High] and [Low], respectively) of E. coli-Xen14 were placed in translucent tubes for detection of PE through RTS. The CFU did not differ (P=0.31) over time with or without KAN presence; they remained stable with 99.93% and 99.98% photon emitters, respectively. However, PE were lower (P<0.0001) in cultures containing KAN than in those containing no KAN (629.8+/-117.7 vs. 3012.0+/-423.5 relative lights units per second [RLU/sec], respectively). On average, the percentage of PE between RTS, for both concentrations, was higher (P<0.05) in the uterine body. In summary, E. coli-Xen14 remained stable with respect to the proportions of photon emitters with or without KAN (used to selectively culture E. coli-Xen14). However, KAN presence suppressed photonic activity. The ability to detect PE through various segments of the reproductive tract demonstrated the feasibility of monitoring the presence of E. coli-Xen14 in the bovine reproductive tract ex vivo.

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

FMT-CT; molecular imaging; atherosclerosis; protease activity; inflammation; in vivo imaging; fluorescence molecular tomography; ProSense

Objective: Proteases are emerging biomarkers of inflammatory diseases. In atherosclerosis, these enzymes are often secreted by inflammatory macrophages, digest the extracellular matrix of the fibrous cap and destabilize atheromata. Protease function can be monitored with protease activatable imaging probes and quantitated in vivo by fluorescence molecular tomography (FMT). To address two major constraints currently associated with imaging of murine atherosclerosis (lack of highly sensitive probes and absence of anatomical information), we compared protease sensors (PS) of variable size and pharmacokinetics and co-registered FMT datasets with computed tomography (FMT-CT).

Methods and results: Co-registration of FMT and CT was achieved with a multimodal imaging cartridge containing fiducial markers detectable by both modalities. A high-resolution CT angiography protocol accurately localized fluorescence to the aortic root of atherosclerotic apoE-/- mice. To identify suitable sensors, we first modeled signal kinetics in-silico and then compared three probes with identical oligo-L-lysine cleavage sequences: PS-5, 5nm in diameter containing 2 fluorochromes , PS-25, a 25nm version with an elongated lysine chain and PS-40, a polymeric nanoparticle. Serial FMT-CT showed fastest kinetics for PS-5 but, surprisingly, highest fluorescence in lesions of the aortic root for PS-40. PS-40 robustly reported therapeutic effects of atorvastatin, corroborated by ex vivo imaging and qPCR for the model protease cathepsin B.

Conclusions: FMT-CT is a robust and observer-independent tool for non-invasive assessment of inflammatory murine atherosclerosis. Reporter-containing nanomaterials may have unique advantages over small molecule agents for in vivo imaging.

Journal Article

Animals; Bioware; Disease Susceptibility; DNA, Bacterial; Lung; Mannose-Binding Lectin; Mice; Mice, Knockout; Reference Values; Reverse Transcriptase Polymerase Chain Reaction; Spleen; Staphylococcal Infections; Xen8.1

Gram-positive organisms like Staphylococcus aureus are a major cause of morbidity and mortality worldwide. Humoral response molecules together with phagocytes play a role in host responses to S. aureus. The mannose-binding lectin (MBL, also known as mannose-binding protein) is an oligomeric serum molecule that recognizes carbohydrates decorating a broad range of infectious agents including S. aureus. Circumstantial evidence in vitro and in vivo suggests that MBL plays a key role in first line host defense. We tested this contention directly in vivo by generating mice that were devoid of all MBL activity. We found that 100% of MBL-null mice died 48 h after exposure to an intravenous inoculation of S. aureus compared with 45% mortality in wild-type mice. Furthermore, we demonstrated that neutrophils and MBL are required to limit intraperitoneal infection with S. aureus. Our study provides direct evidence that MBL plays a key role in restricting the complications associated with S. aureus infection in mice and raises the idea that the MBL gene may act as a disease susceptibility gene against staphylococci infections in humans.