Previous work (Wheeler et al, Gene Therapy 1999; 6: 271-be generated. The SPLP produced could be isolated from 281) has shown that plasmid DNA can be entrapped in empty vesicles by sucrose density gradient centrifugation, 'stabilized plasmid-lipid particles' (SPLP) containing the and exhibited a narrow size distribution (62 ± 8 nm, as fusogenic lipid dioleoylphosphatidylethanolamine (DOPE), determined by freeze-fracture electron microscopy) and a low levels (5-10 mol%) of cationic lipid, and stabilized by high plasmid-to-lipid ratio of 65 g/ mol (corresponding to a polyethyleneglycol (PEG) coating. The PEG moieties are one plasmid per particle) regardless of the DODAC conattached to a ceramide anchor containing an arachidoyl tent. It was found that isolated SPLP containing 20-acyl group (PEG-CerC 20 ). These SPLP exhibit low trans-24 mol% DODAC resulted in optimum transfection of COSfection potencies in vitro, due in part to the long residence 7 and HepG2 cells in vitro, with luciferase expression levels time of the PEG-CerC 20 on the SPLP surface. In this work comparable to those achieved for plasmid DNA-cationic we employed SPLP stabilized by PEG attached to ceralipid complexes. In vivo studies employing an intraperimide containing an octanoyl acyl group (PEG-CerC 8 ), toneal B16 tumor model and intraperitoneal administration which is able to quickly exchange out of the SPLP, to of SPLP also demonstrated maximum luciferase develop systems that give rise to optimized in vitro and in expression for DODAC contents of 20-24 mol% and sigvivo (regional) transfection. A particular objective was to nificantly improved gene expression in tumor tissue as achieve cationic lipid contents that give rise to maximum compared with complexes. We conclude that SPLP stabiltransfection levels. It is shown that by performing the dialyized by PEG-CerC 8 and containing 20-24 mol% cationic sis procedure in the presence of increasing concentrations lipid are attractive alternatives to plasmid DNA-cationic of citrate, SPLP containing up to 30 mol% of the cationic lipid complexes for regional gene therapy applications. lipid dioleoydimethylammonium chloride (DODAC) could

Promising recent investigations have shown that breast malignancies exhibit restricted diffusion on diffusion-weighted imaging (DWI) and may be distinguished from normal tissue and benign lesions in the breast based on differences in apparent diffusion coefficient (ADC) values. In this study, we assessed the influence of intravoxel fat signal on breast diffusion measures by comparing ADC values obtained using a diffusion-weighted single shot fast spin echo sequence with and without fat suppression. The influence of breast density on ADC measures was also evaluated. ADC values were calculated for both tumor and normal fibroglandular tissue in a group of twenty-one women with diagnosed breast cancer. There were systematic underestimations of ADC for both tumor and normal breast tissue due to intravoxel contribution from fat signal on non-fat-suppressed DWI. This ADC underestimation was more pronounced for normal tissue values (mean difference = 40%) than for tumors (mean difference = 27%, p<0.001) and was worse in women with low breast tissue density versus those with extremely dense breasts (p<0.05 for both tumor and normal tissue). Tumor conspicuity measured by contrast-to-noise ratio was significantly higher on ADC maps created with fat suppression and was not significantly associated with breast density. In summary, robust fat suppression is important for accurate breast ADC measures and optimal lesion conspicuity on DWI.

Ultrasound (US)-mediated gene delivery has emerged as a promising non-viral method for safe and selective gene delivery. When enhanced by the cavitation of microbubbles (MBs), US exposure can induce sonoporation that transiently increases cell membrane permeability for localized delivery of DNA. The present study explores the effect of generalizable MB customizations on MB facilitation of gene transfer compared to Definity®, a clinically available contrast agent. These modifications are 1) increased MB shell acyl chain length (RN18) for elevated stability and 2) addition of positive charge on MB (RC5K) for greater DNA associability. The MB types were compared in their ability to facilitate transfection of luciferase and GFP reporter plasmid DNA in vitro and in vivo under various conditions of US intensity, MB dosage, and pretreatment MB-DNA incubation. The results indicated that both RN18 and RC5K were more efficient than Definity®, and that the cationic RC5K can induce even greater transgene expression by increasing payload capacity with prior DNA incubation without compromising cell viability. These findings could be applied to enhance MB functions in a wide range of therapeutic US/MB gene and drug delivery approach. With further designs, MB customizations have the potential to advance this technology closer to clinical application.

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Camera-based in-vivo optical imaging can provide detailed images of living tissue that reveal structure, function, and disease. High-speed, high resolution imaging can reveal dynamic events such as changes in blood flow and responses to stimulation. Despite these benefits, commercially available scientific cameras rarely include software that is suitable for in-vivo imaging applications, making this highly versatile form of optical imaging challenging and time-consuming to implement. To address this issue, we have developed a novel, open-source software package to control high-speed, multispectral optical imaging systems. The software integrates a number of modular functions through a custom graphical user interface (GUI) and provides extensive control over a wide range of inexpensive IEEE 1394 Firewire cameras. Multispectral illumination can be incorporated through the use of off-the-shelf light emitting diodes which the software synchronizes to image acquisition via a programmed microcontroller, allowing arbitrary high-speed illumination sequences. The complete software suite is available for free download. Here we describe the software’s framework and provide details to guide users with development of this and similar software.