Journal Article

IVIS, RediJect Inflammation Probe, chemiluminescence, XenoLight

Due to complex injurious environment where multiple blast effects interact with the body parallel, blast-induced neurotrauma is a unique clinical entity induced by systemic, local, and cerebral responses. Activation of autonomous nervous system; sudden pressure increase in vital organs such as lungs and liver; and activation of neuroendocrine-immune system are among the most important mechanisms that contribute significantly to molecular changes and cascading injury mechanisms in the brain. It has been hypothesized that vagally mediated cerebral effects play a vital role in the early response to blast: this assumption has been supported by experiments where bilateral vagotomy mitigated bradycardia, hypotension, and apnea, and also prevented excessive metabolic alterations in the brain of animals exposed to blast. Clinical experience suggests specific blast-body-nervous system interactions such as (1) direct interaction with the head either through direct passage of the blast wave through the skull or by causing acceleration and/or rotation of the head; and (2) via hydraulic interaction, when the blast overpressure compresses the abdomen and chest, and transfers its kinetic energy to the body's fluid phase, initiating oscillating waves that traverse the body and reach the brain. Accumulating evidence suggests that inflammation plays important role in the pathogenesis of long-term neurological deficits due to blast. These include memory decline, motor function and balance impairments, and behavioral alterations, among others. Experiments using rigid body- or head protection in animals subjected to blast showed that head protection failed to prevent inflammation in the brain or reduce neurological deficits, whereas body protection was successful in alleviating the blast-induced functional and morphological impairments in the brain.

Journal Article

Xen31, Xen 31, MRSA, S. aureus, IVIS, Bioluminescence

Biofilms that develop on indwelling devices are a major concern in clinical settings. While removal of colonized devices remains the most frequent strategy for avoiding device-related complications, antibiotic lock therapy constitutes an adjunct therapy for catheter-related infection. However, currently used antibiotic lock solutions are not fully effective against biofilms, thus warranting a search for new antibiotic locks. Metal-binding chelators have emerged as potential adjuvants due to their dual anticoagulant/antibiofilm activities, but studies investigating their efficiency were mainly in vitro or else focused on their effects in prevention of infection. To assess the ability of such chelators to eradicate mature biofilms, we used an in vivo model of a totally implantable venous access port inserted in rats and colonized by either Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, or Pseudomonas aeruginosa. We demonstrate that use of tetrasodium EDTA (30 mg/ml) as a supplement to the gentamicin (5 mg/ml) antibiotic lock solution associated with systemic antibiotics completely eradicated Gram-positive and Gram-negative bacterial biofilms developed in totally implantable venous access ports. Gentamicin-EDTA lock was able to eliminate biofilms with a single instillation, thus reducing length of treatment. Moreover, we show that this combination was effective for immunosuppressed rats. Lastly, we demonstrate that a gentamicin-EDTA lock is able to eradicate the biofilm formed by a gentamicin-resistant strain of methicillin-resistant S. aureus. This in vivo study demonstrates the potential of EDTA as an efficient antibiotic adjuvant to eradicate catheter-associated biofilms of major bacterial pathogens and thus provides a promising new lock solution.

Journal Article

OsteoSense, IVIS, Animals; Bone Marrow Cells/*cytology/metabolism/physiology; Bone Marrow Transplantation/*methods/physiology; Cells, Cultured; Cellular Microenvironment/genetics/*physiology; Hematopoiesis, Extramedullary/genetics/*physiology; Humans; Hypoxia-Inducible Factor 1, alpha Subunit/genetics/metabolism; Interleukin Receptor Common gamma Subunit/genetics; Mice; Mice, Inbred NOD; Mice, SCID; Mice, Transgenic; Models, Animal; Osteogenesis/genetics/physiology; Species Specificity; *Transplantation, Heterotopic

The interactions between hematopoietic cells and the bone marrow (BM) microenvironment play a critical role in normal and malignant hematopoiesis and drug resistance. These interactions within the BM niche are unique and could be important for developing new therapies. Here, we describe the development of extramedullary bone and bone marrow using human mesenchymal stromal cells and endothelial colony-forming cells implanted subcutaneously into immunodeficient mice. We demonstrate the engraftment of human normal and leukemic cells engraft into the human extramedullary bone marrow. When normal hematopoietic cells are engrafted into the model, only discrete areas of the BM are hypoxic, whereas leukemia engraftment results in widespread severe hypoxia, just as recently reported by us in human leukemias. Importantly, the hematopoietic cell engraftment could be altered by genetical manipulation of the bone marrow microenvironment: Extramedullary bone marrow in which hypoxia-inducible factor 1alpha was knocked down in mesenchymal stromal cells by lentiviral transfer of short hairpin RNA showed significant reduction (50% +/- 6%; P = .0006) in human leukemic cell engraftment. These results highlight the potential of a novel in vivo model of human BM microenvironment that can be genetically modified. The model could be useful for the study of leukemia biology and for the development of novel therapeutic modalities aimed at modifying the hematopoietic microenvironment.

Journal Article

Bioware; PC-3M-luc; hVEGF-luc-PC3M

Background: Preclinical cancer studies increasingly utilize non-invasive imaging modalities. In the current study we have monitored tumor growth and vascular changes using two in vivo imaging tools: surface bioluminescence (BLI) and ultrasound biomicroscopy (UBM). BLI permits visualization of tumor location in the context of the whole body, including metastases localization. UBM imaging then permits high resolution 3D volumetric tumor measurements as well as blood flow estimates down to 200 microns/s. Measurements obtained from these complementary modalities were analyzed and compared to conventional, biochemical markers. Methods: Human prostate cancer cells expressing Firefly Luciferase constitutively (PC-3M-luc-C6) or under the control of hVEGF promoter (hVEGF-luc/PC3M) were implanted into male nude mice via an intradermal or subcutaneous injection. Tumor-bearing mice were subsequently imaged every week for nine weeks starting at week 2, by UBM to measure tumor burden using 3D volumetric analysis, or to estimate blood flow using speckle-variance flow processing. Surface bioluminescence was also acquired 10 minutes post i.p. injection of D-luciferin. In a longitudinal drug intervention study anti-hVEGF antibody (Bevacizumab, 200 ug) was injected i.p. into nude mice with subcutaneous xenografts of PC-3M-luc-C6 or hVEGF-luc/PC-3M twice per week for three weeks, starting at 14 days post-xenograft. UBM and surface BLI imaging were conducted every week. In order to study the correlation between VEGF expression in hVEGF-luc/PC3M xenografts (estimated by BLI) to tumor hypoxia level, mice were injected with pimonidazole hydrochloride (60 mg/kg i.v.) after three weeks of treatment and tumors were harvested for immunostaining analysis. Results: Surface BLI outputs (photons/s) from subcutaneous PC-3M-luc-C6 xenografts were highly correlated to tumor volumes measured using 3D UBM for small tumors (<100 mm3, r=0.92, n=8), yet poorly correlated to tumors of large size (>100 mm3, r=0.079, n=8). BLI signals in subcutaneous hVEGF-luc/PC3M xenografts showed an inverse trend to tumor blood flow. PC-3M-luc-C6 tumors treated with Bevacizumab showed growth inhibition by day 28 as demonstrated by 3D UBM (control vs treated = 67.27 vs 48.54 mm3). Moreover, control xenografts showed increased average BLI output over time, whereas treated tumors showed variation in BLI output. Necrosis, hypoxia and blood flow estimates were also investigated. Conclusions: Surface bioluminescence imaging demonstrated high correlations to accurate 3D UBM volumetric measurements of small tumor volumes, suggesting its usefulness in tracking early tumor growth quantitatively in drug intervention studies. A complementary imaging modality, like ultrasound biomicroscopy, is recommended to monitor tumor burden in advanced stages.

Journal Article

In vivo imaging; AngioSPARK

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