Dual-reporter Imaging and its Potential Application in Tracking Studies.

By tracking reporter molecules such as green fluorescent protein and luciferase, researchers can determine physiological status and follow processes both in vitro and in vivo.Here, we describe a dual-reporter imaging method, in which a fusion of eGFP and Luc2 is introduced into hosts using lentiviral particles based on HIV-1. The fusion molecule is both fluorescent and bioluminescent, and is therefore ideal as an optical marker in clinical and research applications.We characterized multiple technical indices of the molecule,including sensibility, biocompatibility, lifetime, and others.Lentiviral particles carrying the reporter were strongly infective in endothelial progenitor (EPC) and GL261 glioma cells,as well as in live mice. By transforming Luc2-eGFP into hosts, morphological and quantitative data can be collected not only from tissue specimens but also from live animal models.

[Cement leakages in percutaneous vertebroplasty:analysis of postoperative computed tomography].

OBJECTIVE: To evaluate the influencing factors of cement leakage in vertebroplasty for the treatment of osteoporosis vertebral compression fracture (OVCF) and vertebral metastases (VM). METHODS: Retrospective analysis was conducted for 653 vertebrae in 356 patients undergoing vertebroplasty at our hospital from May 2007 to January 2011. 251 cases had 438 vertebrae with painful OVCF while 105 cases had 215 vertebrae with VM. Pre-operative computed tomography (CT) was performed to determine the presence of cortical defects or osteolysis and within 3 days after PVP to observe the distribution of polymethylmethacrylate (PMMA) in vertebrae and whether leakage occurred. Volume of PMMA injected into each vertebral body and types of cement leakage were compared between the OVCF and VM groups by Z test or χ². The correlation between cortical defects and cement leakages around vertebrae was assessed with Pearson correlation coefficient. RESULTS: The successful rate of PVP was 100%. The mean volume of PMMA injected into each vertebra was (5.0 ± 2.0) ml and (4.0 ± 1.7) ml in the OVCF and VM groups respectively (P < 0.05). Asymptomatic PMMA leakage was demonstrated by CT in 93 vertebrae (21.2%) in the OVCF group and in 53 vertebrae (28.8%) in the VM group respectively (P < 0.05). Cement leakages into disk were found in 58 vertebrae in the OVCF group and 16 vertebrae in the VM group respectively (P = 0.025). Cement leakages into paravertebral vein were found in 12 vertebrae in the OVCF group and 26 vertebrae in the VM group respectively (P < 0.0001). Correlation was found between cortical defects and cement leakage into paravertebral soft tissues in the OVCF group (r = 0.14) or in the VM group (r = 0.27), between end-plate defects and cement leakage into disk in the OVCF group (r = 0.29) or in the VM group (r = 0.31). CONCLUSION: As a common occurrence in vertebroplasty, cement extravasation is well-tolerated in most patients. It occurs more frequently in the patients with VM than those with OVCF, especially in cases of leakage into paravertebral vein. Cement leakage into disc or paravertebral soft tissue is predisposed in vertebrae with end plate, cortical defects or osteolysis.

Biodegradable PTX-PLGA-coated magnesium stent for benign esophageal stricture: An experimental study.

Biodegradable stents can degrade step by step and thereby avoid secondary removal by endoscopic procedures in contrast to metal stents. Herein, a biodegradable composite stent, a magnesium (Mg)-based braided stent with a surface coating of poly (lactic-co-glycolic acid) (PLGA) containing paclitaxel (PTX), was designed and tested. By adding this drug-loaded polymer coating, the radial force of the stent increased from 33 Newton (N) to 83 N. PTX was continuously released as the stent degraded, and the in vitro cumulative drug release in phosphate-buffered saline for 28 days was 115 ± 13.5 µg/mL at pH = 7.4 and 176 ± 12 µg/mL at pH = 4.0. There was no statistically significant difference in the viability of fibroblasts of stent extracts with different concentration gradients (P > 0.05), while the PTX-loaded stents effectively promoted fibroblast apoptosis. In the animal experiment, the stents were able to maintain esophageal patency during the 3-week follow-up and to reduce the infiltration of inflammatory cells and the amount of fibrous tissue. These results showed that the PTX-PLGA-coated Mg stent has the potential to be a safe and effective approach for benign esophageal stricture. STATEMENT OF SIGNIFICANCE: We designed a biodegradable composite stent, having poly (lactic-co-glycolic acid) (PLGA) containing paclitaxel (PTX) coated the surface of the magnesium (Mg)-based braided stent. We evaluated in vitro and in vivo characteristics of the Mg esophageal stent having a PLGA coating plus a variable concentration of PTX in comparison with the absence of PTX PLGA coating. The PTX PLGA stents exerted higher radial force than stents without coating, degraded more quickly in an acid medium, and effectively promoted fibroblast apoptosis in vitro experiments. In a rabbit model of caustic-induced esophageal stricture, there was an increased lumen and decreased inflammation of the esophageal wall in the animals stented with PTX-PLGA versus the sham group, indicating a potential approach for benign esophageal stricture.

The Exploration of a Novel Biodegradable Drug-Eluting Biliary Stent: Preliminary Work.

PURPOSE: To explore the degradation, drug release, and mechanical properties of drug-incorporated films made of different ratios of poly(lactic-co-glycolic acid) (PLGA) and different amounts of paclitaxel (PTX), which may serve as the material platform for the manufacturing of biodegradable drug-eluting biliary stents. MATERIALS AND METHODS: PLGA of different lactic acid/glycolic acid ratios (50/50, 70/30, and 80/20) and 0%, 10, 20, and 30% weight by weight (w/w) PTX was mixed to make PLGA films, which were then cut into small pieces for further testing. Films were immersed in phosphate-buffered saline (pH 7.4) for a maximum of 11 weeks. Samples were taken randomly at Day 2, 4, 6, 8, 10, 12, 14, and weekly thereafter until Week 11 to test tensile strength, weight loss, pH value of the soaking solution, and drug release. The morphology of films was observed using scanning electron microscope (SEM). RESULTS: At Week 10 of degradation, PLGA 80/20 still withstood a tensile strength of 9.7 newton (N), while PLGA 50/50 and 70/30 cracked spontaneously since Day 4. At Week 11, weight loss of PLGA 50/50, 70/30, and 80/20 was 95.15, 82.32, and 16.17%, respectively; and the lowest pH value of soaking solution was 1.87, 1.95, and 6.58, respectively. Drug release of 10, 20, and 30% PTX groups was 3.52-4.48%, 1.90-2.26%, and 1.44-2.06%, respectively. SEM proved smooth films before degradation; however, after the tensile strength was lost, cracks could be seen. CONCLUSION: The degradation rate of PLGA can be controlled by altering lactic acid/glycolic acid ratio. Overall, PLGA 50/50 and 70/30 degrade significantly faster than 80/20. PLGA can serve as an effective drug carrier for PTX while being the stent strut, and PTX can be slowly released as PLGA degrades.

Seeding endothelial progenitor cells on a self-expanding metal stent: an in vitro study.

PURPOSE: To demonstrate the feasibility of seeding a self-expanding metal stent with endothelial progenitor cells to enhance rapid reendothelialization, which is postulated to prevent local thrombus formation and restenosis after vascular intervention. MATERIALS AND METHODS: Endothelial progenitor cells and fibrinogen were isolated from the peripheral blood of a domestic swine and then cultured and identified. Ten self-expanding nitinol stents were incubated in the culture medium with a cell concentration of 1 x 10(6)/mL with (n = 5, study group) or without (n = 5, control group) fibrin gel (5 mg/mL fibrinogen and 0.10 NIHU/mL thrombin) for 24 hours. The cell coverage of the stents was documented with en face photography and scanning electron microscopy. After simulated use in vitro, the cells were removed from each stent, counted with a cytometer, sequentially cultured for three passages, and identified again to compare their properties with those of the original seeding line. RESULTS: After seeding the stent with the combination of endothelial progenitor cells and the fibrin gel coating, the stents took on a tube-like appearance with a confluent monolayer membrane. After digestion with trypsin, a mean of 2.5 x 10(5) +/- 1.3 cells were obtained from the fibrin gel stent (study group); fewer cells (4 x 10(4) +/- 1.5) were recovered from the bare stents (control group) (P < .01). The recovered cells, after amplification with culture, demonstrated the properties of the original endothelial progenitor cells. CONCLUSIONS: An endothelial progenitor cell-coated stent can be successfully fabricated by using fibrin gel as the bonding agent in vitro. Further in vivo research is warranted.

[Value of intraosseous venography in percutaneous vertebroplasty for treatment of symptomatic vertebral hemangiomas].

OBJECTIVE: To evaluate the clinical efficacy of percutaneous vertebroplasty (PVP) in patients with symptomatic vertebral hemangiomas and determine whether prior intraosseous venography decreases extravertebral leakage of PMMA and improves clinical outcomes in these procedures. METHODS: Retrospective review was conducted on 45 consecutive patients with 53 symptomatic vertebral hemangiomas associated with chronic pain (all cases) or paralysis caused by spinal cord compression (1 case) or vertebral compression fractures (3 cases) treated with PVP at our institution to define two populations. Group A consisted of 27 vertebral hemangiomas in 23 patients who underwent intraosseous venography before injection polymethylmethacrylate (PMMA). Group B consisted of 26 vertebrae in 22 patients who underwent injection PMMA without prior venography. CT was done 1 to 3 days after PVP to observe PMMA distribution in vertebrae and whether leakage. Clinical outcomes, included pain relief, leakage of PMMA, volume of PMMA injected, expense and X-ray exposure times in each vertebral body, were compared in the two groups by using χ(2) or t test. RESULTS: No significant difference was seen between the groups with respect to age, sex, the number of treated vertebrae, or preprocedural degrees of pain. The successful rate of technique of PVP was 100%. The mean volume of PMMA injected in each vertebra was 3.96 ml. CR, PR and NR was obtained respectively 84.5%, 13.3% and 2.2% during 6 months to 5 years of follow-up expect one case had unrelieved pain in group A. At 6 months after PVP, 22 cases (95.7%) in group A and 22 cases (100%) in group B achieved adequate pain relief (P = 0.323). 6 vertebrae (6/27) in group A and 2 vertebrae (2/26) in group B with asymptomatic leakage of PMMA were demonstrated by CT (P = 0.140). The mean volume of PMMA injected in each vertebra was 3.70 ml in group A and 4.23 ml in group B (P = 0.157). The mean expense of each vertebra was ¥7.24 × 10(3) in group A and ¥5.84 × 10(3) in group B (P = 0.000), the mean decreases were ¥1.4 × 10(3) in group B than group A. The mean X-ray exposure times on each vertebral body was 13.28 minutes in group A and 8.78 minutes in group B (P = 0.000), the mean decreases were 4.5 minutes in group B than group A. CONCLUSIONS: PVP is an effective and safe procedure for treating symptomatic vertebral hemangiomas. Prior intraosseous venography does not significantly improve the effectiveness or safety of PVP for vertebral hemangiomas performed by qualified, experienced operators, on the other hand, it increases the expense and X-ray exposure times of PVP.

Nomogram for Predicting Intradiscal Cement Leakage Following Percutaneous Vertebroplasty in Patients with Osteoporotic Related Vertebral Compression Fractures.

BACKGROUND: Intradiscal cement leakage (ICL) is a common complication following percutaneous vertebroplasty (PVP). However, the risk factors for such a complication are under debate and there is no accurate predictive nomogram to predict ICL. OBJECTIVES: To establish an effective and novel nomogram for ICL following PVP in patients with osteoporotic-related vertebral compression fractures (OVCFs). STUDY DESIGN: This was a retrospective study approved by the Institutional Review Board of our institution. SETTING: This study consists of patients from a large academic center. METHODS: Patients with OVCFs who underwent their first PVP in our department between January 2007 and December 2013 were included in this study. All the potential risk factors of ICL after PVP were recorded. Univariate and multivariate analyses were used to identify the independent risk factors. The nomogram was then created based on the identified independent risk factors. RESULTS: A total of 241 patients and 330 vertebrae were included. The mean age of the patients was 73.5 (SD 7.9) years old, and the mean number of treated vertebrae was 1.4 per person. ICL was observed in 93 (28.2%) of the treated vertebrae. Greater fracture severity (P = 0.016), cortical disruption of the endplate (P < 0.0001), absence of Kummell's disease (P = 0.010), and higher computed tomography (CT) values (P = 0.050) were the independent risk factors for ICL. LIMITATIONS: The main limitation of this study is that it is a retrospective study. CONCLUSION: Greater fracture severity, cortical disruption of the endplate, absence of Kummell's disease, and higher CT values are the independent risk factors for ICL. The novel nomogram gives an accurate prediction of ICL.

Rational Design of Branched Nanoporous Gold Nanoshells with Enhanced Physico-Optical Properties for Optical Imaging and Cancer Therapy.

Reported procedures on the synthesis of gold nanoshells with smooth surfaces have merely demonstrated efficient control of shell thickness and particle size, yet no branch and nanoporous features on the nanoshell have been implemented to date. Herein, we demonstrate the ability to control the roughness and nanoscale porosity of gold nanoshells by using redox-active polymer poly(vinylphenol)-b-(styrene) nanoparticles as reducing agent and template. The porosity and size of the branches on this branched nanoporous gold nanoshell (BAuNSP) material can be facilely adjusted by control of the reaction speed or the reaction time between the redox-active polymer nanoparticles and gold ions (Au3+). Due to the strong reduction ability of the redox-active polymer, the yield of BAuNSP was virtually 100%. By taking advantage of the sharp branches and nanoporous features, BAuNSP exhibited greatly enhanced physico-optical properties, including photothermal effect, surface-enhanced Raman scattering (SERS), and photoacoustic (PA) signals. The photothermal conversion efficiency can reach as high as 75.5%, which is greater than most gold nanocrystals. Furthermore, the nanoporous nature of the shells allows for effective drug loading and controlled drug release. The thermoresponsive polymer coated on the BAuNSP surface serves as a gate keeper, governing the drug release behavior through photothermal heating. Positron emission tomography imaging demonstrated a high passive tumor accumulation of 64Cu-labeled BAuNSP. The strong SERS signal generated by the SERS-active BAuNSP in vivo, accompanied by enhanced PA signals in the tumor region, provide significant tumor information, including size, morphology, position, and boundaries between tumor and healthy tissues. In vivo tumor therapy experiments demonstrated a highly synergistic chemo-photothermal therapy effect of drug-loaded BAuNSPs, guided by three modes of optical imaging.

ANVCFV Score System: Assessment for Probability of New Vertebral Compression Fractures after Percutaneous Vertebroplasty in Patients with Vertebral Compression Fractures.

BACKGROUND: Percutaneous vertebroplasty (PVP) is widely used for the treatment of painful vertebral compression fractures (VCFs). However, new VCFs occur frequently after PVP. OBJECTIVES: We aim to establish an objective risk score system to assess the possibility of new vertebral fractures in patients with VCFs undergoing PVP. STUDY DESIGN: This study was a retrospective study, and it was approved by the Institutional Review Board of our 2 institutions. SETTING: This study consists of patients from 2 large academic centers. METHODS: Patients with VCFs who underwent their first PVP and met the inclusion criteria between January 2007 and December 2013 at Hospital A (training cohort) and Hospital B (validation cohort) were included. In the training cohort, the independent risk factors for new VCFs after PVP were identified by multivariate stepwise backward Cox regression analysis from the risk factors selected by univariate analysis and Harrell's C-statistics and used to develop the score system (assessment for new VCFs after PVP [ANVCFV]) to predict the probability of new VCFs. RESULTS: In total, 397 patients (training cohort: n = 241; validation cohort: n = 156) were included in this study. In the training cohort, the ANVCFV score was developed based on 5 independent risk factors for the new VCFs after PVP, including lower computed tomography (CT) values, pre-existing old VCFs, intradiscal cement leakage, more than one vertebra treated, and superior or inferior marginal cement distribution in the vertebra. The patients were divided into 2 groups by the ANVCFV score of -1.5 to 8.5 vs. > 8.5 points in the probability of new VCFs (median fracture-free time: 1846 vs. 732 days; P < 0.001) in the training cohort. The accuracy of this score system was 77.4% for the training cohort and 85.3% for the validation cohort. LIMITATIONS: The main limitations of this study are that it is a retrospective study and that there is a significant difference of the treated vertebrae of PVP per session between the 2 cohorts. CONCLUSION: Patients who underwent their first PVP with an ANVCFV score > 8.5 points may exhibit an increased chance of suffering from new VCFs.

Magnetic resonance imaging of post-ischemic blood-brain barrier damage with PEGylated iron oxide nanoparticles.

Blood-brain barrier (BBB) damage during ischemia may induce devastating consequences like cerebral edema and hemorrhagic transformation. This study presents a novel strategy for dynamically imaging of BBB damage with PEGylated supermagnetic iron oxide nanoparticles (SPIONs) as contrast agents. The employment of SPIONs as contrast agents made it possible to dynamically image the BBB permeability alterations and ischemic lesions simultaneously with T2-weighted MRI, and the monitoring could last up to 24 h with a single administration of PEGylated SPIONs in vivo. The ability of the PEGylated SPIONs to highlight BBB damage by MRI was demonstrated by the colocalization of PEGylated SPIONs with Gd-DTPA after intravenous injection of SPION-PEG/Gd-DTPA into a mouse. The immunohistochemical staining also confirmed the leakage of SPION-PEG from cerebral vessels into parenchyma. This study provides a novel and convenient route for imaging BBB alteration in the experimental ischemic stroke model.

Ghrelin suppression and fat loss after left gastric artery embolization in canine model.

PURPOSE: To evaluate the effects of left gastric artery embolization (LGAE) on plasma ghrelin levels, abdominal fat, and body weight in beagles. METHODS: The institutional animal care and use committee approved this study. Fifteen healthy adult beagles (12 male and three female animals) were randomly divided into three experimental groups: LGAE was proceeded with mixed emulsion of bleomycin A(5) hydrochloride and lipiodol (group A), and polyvinyl alcohol particles (group B). Transcatheter saline injections in the left gastric artery were performed as a control. Weight and fasting plasma ghrelin levels were obtained at baseline and at weekly intervals for 8 weeks after the procedure in all animals. All animals were scanned and measured by multidetector computed tomography at baseline and at week 8 for evaluation of abdominal fat. RESULTS: In LGAE-treated animals, plasma ghrelin and body weight significantly decreased compared to control animals (group A: P = 0.007 and P = 0.000; group B: P = 0.004 and P = 0.000, respectively). Subcutaneous fat size was also significantly reduced (P = 0.011 and P = 0.027 for groups A and B, respectively). The decreasing percentage in ghrelin levels at week 6 (peak of recovery) of LGAE-treated animals were negatively correlated with the size of area supplied by left gastric artery (r = -0.693, P = 0.026). CONCLUSION: LGAE could suppress the plasma concentration of ghrelin, which results in subcutaneous fat size reduction and weight loss. Compensatory ghrelin production might occur in the remnant gastric fundus after LGAE.

Enhancement of p53 gene transfer efficiency in hepatic tumor mediated by transferrin receptor through trans-arterial delivery.

Transferrin-DNA complex mediated by transferrin receptor in combination with interventional trans-arterial injection into a target organ may be a duel-target-oriented delivery means to achieve an efficient gene therapy. In this study, transferrin receptor expression in normal human hepatocyte and two hepatocellular-carcinoma cells (Huh7/SK-Hep1) was determined. p53-LipofectAMINE with different amounts of transferrin was transfected into the cells and the gene transfection efficiency was evaluated. After VX2 rabbit hepatocarcinoma model was established, the transferrin-p53-LipofectAMINE complex was delivered into the hepatic artery via interventional techniques to analyze the therapeutic p53 gene transfer efficiency in vivo by Western blot, immunohistochemical/immunofluorescence staining analysis and survival time. The results were transferrin receptor expression in Huh7 and SK-Hep1 cells was higher than in normal hepatocyte. Transfection efficiency of p53 was increased in vitro in both Huh7 and SK-Hep1 cells with increasing transferrin in a dose-dependent manner. As compared to intravenous administration, interventional injection of p53-gene complex into hepatic tumor mediated by transferrin-receptor, could enhance the gene transfer efficiency in vivo as evaluated by Western blot, immunohistochemical/immunofluorenscence staining analyses and improved animal survival (H = 12.567, p = 0.0019). These findings show the transferrin-transferrin receptor system combined with interventional techniques enhanced p53-gene transfer to hepatic tumor and the duel-target-oriented gene delivery may be an effective approach for gene therapy.

A simplified method of opacifying and mixing acrylic cement for percutaneous vertebroplasty: a clinical and in vitro study.

The objective of this study was to simplify the opacifying mixing process of the bone cement and contrast used for percutaneous vertebroplasty (PVP). We performed a biomechanical study of polymethyl methacrylate (PMMA) (Corinplast 3) using three different mixtures of PMMA, monomer, and contrast: group I, 2:1; group II, 3:2; group III, 3:2:1 ratio of powder/monomer/iodinated contrast (Omnipaque). In vitro biomechanical testing of ultimate compressive strength was carried out in all samples. Following the conclusion of a proper bone cement mixture regimen drawn from the in vitro study, PVP was performed in 125 patients: 58 with cancer, 12 with hemangioma, and 54 with osteoporotic fracture. The ultimate compressive strength in group III was decreased by 38% compared to groups II and I. Proper fluoroscopic visualization was achieved in all PVP procedures using this mixture. There were no major complications associated with injection of the cement mixture. Complete (CR) and partial response (PR) was obtained in 64% and 32.8%, respectively. No further vertebral collapse occurred during follow-up. The regimen using iodinated contrast for cement visualization during PVP provides a simple and convenient new method for mixing. Although the biomechanical strength is altered by the contrast medium added, it seems insignificant in clinical practice based on the authors' limited experience.