Can Magnetic Resonance Imaging Be the Key Technique to Visualize and Investigate Endovascular Biomaterials?

OBJECTIVE

Magnetic resonance imaging (MRI) is an established modality in clinical use but may be potentially underutilized to visualize and investigate biomaterials. As its use is totally contraindicated only for ferromagnetic devices, it was employed to visualize deployment, biofonctionality, healing, and biodurability of a commercially available endovascular device, namely the Medtronic-AVE AneuRx. The quality of the observations coupled with the absence of ionizing radiations are likely to make this technique an attractive imaging modality in the future.

METHOD

The potential benefits of the MRI technique were investigated in a GE Vectra-MR 0.5T MRI for the Medtronic-AVE AneuRx endovascular prosthesis, under different conditions: undeployed i.e., inserted in the delivery cartridge as received from the manufacturer (step 1), deployed in a mock glass-aneurysm tube (step 2), and as a pathological explant harvested at the autopsy of a patient (step 3). The device was submitted to X-rays for examination in addition to MRI. At step 3, the device was further investigated with light microscopy and scanning electron microscopy (SEM) together with X-ray diffraction.

RESULTS

The device which was inserted and pleated in the delivery cartridge did not demonstrate any significant observation either in MRI or in X-rays. When it was deployed in the mock aneurysmal glass tube, light artefacts were associated with the T2 weighed FSE images around the Nitinol whereas X-rays gave images of indisputable interest. Similar results were noted using the explanted device. Very high contrasts were obtained with T1 whereas T2 images were almost defect free. The X-rays allowed to accurate imaging of the Nitinol skeleton but were poor to discriminate between the different tissues. Pathology observations using light microscopy were not really challenged, as the magnetic resonance imaging was performed using a 0.5T machine.

DISCUSSION

The benefits of magnetic resonance imaging as a quality control technique to examine an endovascular device within its cartridge remains ill defined. Similarly, the role of conventional X-rays is unknown. The observation of devices fully deployed in a mock aneurysmal glass-tube under MRI are potentially useful but X-rays images allowed better definition. The MRI examination of the explanted device does permit observations related to the healing of the device that might be obtained in vivo and, thus offers new avenues for the follow-up of implanted devices. The pathological investigations brought additional informations about the tissues and the corrosion of the Nitinol. However, it is unlikely that MRI will permit detailed analysis of the biomaterials and in particular the corrosion process of the stents.

CONCLUSION

These early observations of the follow-up of devices using MRI warrant further investigation. The absence of ionizing radiation with MRI makes this technique particularly attractive. As there is no emission of ionizing radiation associated with magnetic resonance, it is recommended that further investigation using this environment friendly technique for the follow-up of devices made of biomaterials that are MRI compatible.

Combination of beta-TCP and BMP-2 gene-modified bMSCs to heal critical size mandibular defects in rats

OBJECTIVE

To investigate the effects of mandibular defects repaired by a tissue engineered bone complex with beta-tricalcium phosphate (beta-TCP) and bone morphogenic protein-2 (BMP-2) gene-modified bone marrow stromal cells (bMSCs).

MATERIALS AND METHODS

bMSCs derived from Fisher 344 rats were cultured and transduced with adenovirus AdBMP-2, AdEGFP gene in vitro. Osteogenic differentiation of bMSCs was determined by alkaline phosphatase staining, von Kossa assay and reverse transcription-polymerase chain reaction. Gene transduced or untransduced bMSCs were seeded on beta-TCP scaffolds to repair mandibular full thickness defects with a diameter of 5 mm. Eight weeks post-operation, X-ray examination, micro-computerized tomography and histological and histomorphological analysis were used to evaluate the bone healing effects.

RESULTS

Alkaline phosphatase staining and mineralized nodules formation were more pronounced in AdBMP-2 group 14 days after gene transduction when compared with that of AdEGFP or untransduced group. The mRNA expression of osteopontin and osteocalcin also significantly increased 9 days after AdBMP-2 gene transduction. Mandibular defects were successfully repaired with AdBMP-2-transduced bMSCs/beta-TCP constructs. The percentage of new bone formation in AdBMP-2 group was significantly higher than that of other control groups.

CONCLUSIONS

Bone morphogenic protein-2 regional gene therapy together with beta-TCP scaffold could be used to promote mandibular repairing and bone regeneration.

Variants in KCNQ1 are associated with susceptibility to type 2 diabetes in the population of mainland China

AIMS/HYPOTHESIS

Two recent genome-wide association studies have identified several novel type 2 diabetes susceptibility variants in intron 15 of the KCNQ1 gene. We aimed to evaluate the effects of the variants in KCNQ1 on type 2 diabetes and metabolic traits in the population of mainland China.

METHODS

Three candidate single nucleotide polymorphisms were genotyped in 1,912 individuals with type 2 diabetes and 2,041 normal controls using the ligase detection reaction method.

RESULTS

We confirmed the association of KCNQ1 with type 2 diabetes in the population of mainland China. Allele frequency ORs of the three single nucleotide polymorphisms (SNPs) were: rs2237892 (OR 1.19, 95% CI 1.08-1.31, p = 3.0 x 10(-4)); rs2237895 (OR 1.20, 95% CI 1.09-1.32, p = 1.9 x 10(-4)); and rs2237897 (OR 1.24, 95% CI 1.13-1.36, p = 3.9 x 10(-5)). We also found a significant difference in the distribution of the global haplotypes between the type 2 diabetes group and the normal control group (p = 2.6 x 10(-5)). In addition, in the control group SNP rs2237892 was marginally associated with increasing fasting plasma glucose and SNPs rs2237892 and rs2237897 were associated with HbA(1c). Furthermore, for all three variants, homozygous carriers of the diabetes-associated allele had significantly decreased BMI and waist circumferences.

CONCLUSIONS/INTERPRETATION

Our investigation confirmed the effects of KCNQ1 variants on type 2 diabetes risk in the Chinese population.

The Archaeotools project: faceted classification and natural language processing in an archaeological context

This paper describes 'Archaeotools', a major e-Science project in archaeology. The aim of the project is to use faceted classification and natural language processing to create an advanced infrastructure for archaeological research. The project aims to integrate over 1 x 10(6) structured database records referring to archaeological sites and monuments in the UK, with information extracted from semi-structured grey literature reports, and unstructured antiquarian journal accounts, in a single faceted browser interface. The project has illuminated the variable level of vocabulary control and standardization that currently exists within national and local monument inventories. Nonetheless, it has demonstrated that the relatively well-defined ontologies and thesauri that exist in archaeology mean that a high level of success can be achieved using information extraction techniques. This has great potential for unlocking and making accessible the information held in grey literature and antiquarian accounts, and has lessons for allied disciplines.

Distribution of phthalate esters in soil of e-waste recycling sites from Taizhou city in China

In recent years, increasing concern has surrounded the consequences of improper electric and electronic waste (e-waste) disposal. In this paper, Phthalate esters (PAEs) including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), Di-(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP) in the e-waste soils were collected and analyzed from sites Fengjiang, Nanshan and Meishu in Taizhou city. The result showed that the total PAEs concentrations ranged from 12.566 to 46.669 mg/kg in these three sites. DEHP, DBP and DEP were the major phthalates accounting for more than 94% of total phthalates studied. Comparing to the results from other studies, the e-waste soils from Taizhou city were severely contaminated with PAEs.

Altered mechanosensitive properties of vagal afferent fibers innervating the stomach following gastric surgery in rats

BACKGROUND AND AIMS

Several types of gastric surgeries have been associated with early satiety, dyspepsia and food intolerances. We aimed to examine alterations in gastric vagal afferents following gastric surgery-fundus ligation.

METHODS

Six week old, male Sprague-Dawley rats underwent chronic ligation (CL) of the fundus. Sham rats underwent abdominal surgery, but without ligation. Another group of rats underwent acute ligation (AL) of the fundus immediately prior to experiments. CL and sham rats were allowed to grow to age 3-4 months. Food intake and weights were recorded post-operatively. Gastric compliance and gastric wall thickness was measured at baseline and during gastric distension (GD). Extracellular recordings were made to examine response characteristics of vagal afferent fibers to GD and to map the stomach receptive field (RF). The morphological structures of afferent terminals in the stomach were examined with retrograde tracings from the nodose ganglion.

RESULTS

The CL group consumed significantly less food and weighed less than sham control. The mean compliance of the CL group was significantly less than control, but higher than the AL group. The spontaneous firing and responses to GD of afferent fibers from the CL rats were significantly higher than AL rats. There was a marked expansion of the gastric RF in the CL rats with significant reorganization and regeneration of intramuscular array (IMA) terminals. There was no difference in total wall or muscle thickness among the groups.

CONCLUSION

CL results in aberrant remodeling of IMAs with expansion of the gastric RF and alters the mechanotransduction properties of vagal afferent fibers. These changes could contribute to altered sensitivity following gastric surgery.

A phase I study assessing the feasibility and safety of intraductal pegylated liposomal doxorubicin (PLD) in women with breast cancer

e11506

Background: Most breast cancers originate in epithelial cells lining the breast ducts. Preclinical data suggest that intraductal administration of chemotherapy including PLD decrease tumor volume, prevent the development of new lesions, and eradicate pre-malignant disease. We initiated a clinical trial to determine the feasibility, safety, and maximum tolerated dose of PLD administered into one duct of women awaiting mastectomy. Methods: Women 18 or older awaiting mastectomy for breast cancer were eligible. Preoperative chemotherapy was allowed. T4 tumors, prior breast irradiation, or surgeries that may have altered the ductal system were excluded. Nipple aspiration and ductal cannulation were completed and the first 3 women received 5 mL of intraductal dextrose. PLD was administered to subsequent participants on a dose escalation schema based on preclinical pharmacokinetic and safety data. Serial doxorubicin (Dox) and doxorubicinol (Doxol) concentrations were determined in plasma by LC/MS/MS. At mastectomy (completed at least 2 weeks after intraductal administration of PLD), blue dye was injected into the treated duct and tissue was obtained for pharmacokinetic and biomarker analysis. Results: From 2/06 to 6/08, 14 women enrolled, and 12 underwent all study procedures. All dose levels up to 10 mg PLD per one duct were completed without serious adverse events. Median pain score was 0.9 (0–2.3). Intraductal PLD resulted in a dose-dependent increase in both systemic and local exposure to dox and doxol. Neither dox nor the metabolite was detected in the contralateral breast. Systemic exposure was lower than with conventionally administered PLD. Inflammatory changes were not observed on histopathological review of mastectomy specimens. Conclusions: We have established the logistics of intraductal administration of agents in an outpatient setting and it is feasible in women with and without prior chemotherapy. Biomarker data will be completed prior to the meeting. Future studies will evaluate other agents administered to one or more ducts.

[Table: see text]

Phase I study of enzastaurin (ENZ) and bevacizumab (BV) in patients with advanced cancer: Safety, pharmacokinetics (PK), and response assessment

3517

Background: ENZ, an oral kinase inhibitor, suppresses tumor growth through PKC and PI-3 kinase/AKT. BV binds VEGF and inhibits angiogenesis. Since ENZ and BV are complementary in inhibiting angiogenesis, we conducted a Phase I study of ENZ / BV. Methods: Eligible patients (pts) had advanced cancer, adequate organ function and no co-morbidities for increased risk of drug-related toxicities. Six pts were enrolled per cohort; if ≤1 DLT the next cohort opened. A loading dose of ENZ 1125 mg was given on Day 1, C1. After 1 cohort combining ENZ 500 mg/QD and BV at 5mg/kg IV q 2 wks, subsequent cohorts alternated pts between BV 10 mg/kg IV q 2 wks and BV 15 mg/kg IV q 3wks with escalating doses of ENZ (500 mg/QD, 250 mg/BID, and 375 mg/BID) for a total of 7 cohorts. DLT was defined as C1: Grade (G)4 neutropenia ≥7 days, febrile neutropenia, G3 thrombocytopenia with bleeding or G4 thrombocytopenia; G3/G4 non-hematological toxicities, and toxicities associated with BV. ENZ PK was performed at steady-state on Day 1, C2. Results: 43 pts (21 with ovarian cancer) are evaluable for toxicity. Two DLTs (G3 elevated aminotransferase and intraparenchymal hemorrhage) occurred at different dose levels. No apparent increase in ENZ or BV toxicity was seen. Two SAEs (DVT and myocardial ischemia) in two pts occurred at DL 3 after 3 cycles and 13 cycles, respectively. Common toxicities included fatigue, chromaturia, dry/sore mouth, nausea and diarrhea. Nine of 43 pts (21%) had a response (CR, PR), 6 responses were in the ovarian subset (29%). Median time to progression was 3.9 mos (range 0–19.2 mos) and 7.7 mos for ovarian pts (range 0.3–19.2 mos). Overall, 43% remained on study without disease progression for >6 mos (51% of ovarian pts remained on study for >6 mos). Mean steady-state ENZ concentrations (%CV) at 500 mg/QD, 250mg/BID and 375mg/BID were 1080 nmol/L (82.8 %), 516 nmol/L (102%) and 1120 nmol/L (93.3%), respectively. Conclusions: The addition of ENZ to BV in any of the currently approved BV dosing schedules is well tolerated and clinically active in advanced cancer pts. ENZ exposures are highly variable and comparable across the three dose groups. The combination of ENZ / BV demonstrates encouraging activity, specifically in our population of ovarian cancer pts.

[Table: see text]

A pilot study of biological markers (BM) as predictors for response and prognosis in patients (pts) with R0 resected gastric cancer (GC)

e22076

Background: To evaluate clinical value of biological markers and their prognostic significance in gastric cancer as well as prediction to clinic outcome; To select preference marker for targeted therapy in high risk patients hence to guide personalized treatment. Methods: Retrieved from total 394 patients treated during the period of Jan 2004 to June 2006 of Cancer Hospital, Fudan University with complete medical records and follow up data, 84 patients with pre- and post- operative biological markers examined were selected. All of these patients underwent R0 gastrectomy, 61 (72.6%) patients underwent D2 resection. Forty- one (48.8%) patients received ≥ 4 cycles adjuvant chemotherapy. Preoperative tumor markers include: CEA, AFP, CA199, CA50, CA72–4, CA24–2 and postoperative immunohistochemical examination include: Bax, Bcl-2, P27, CyclinD1, TOPO2, MDR, GST-π, Ki67, AgNOR, EGFR, P21, P53, PCNA, C-myc and Neu were analyzed. Univariate, multivariate and Logistic regression analysis were performed and Kapan-Meier estimates were calculated. Results: For the whole group, 2-year OS and PFS were 76% and 66% respectively. Logistic regression analysis showed bcl-2, ki67, c-myc2 and Neu were relative with more nodal involvement. Patients with lower level of CEA, CA72–4 and higher level of cyclin D1 suivived longer than the other patients. There were different clinical significance with those biomarkers. Patients with lower level of cyclinD1, CEA had more local regional recurrence (p=0.026) while patients with higher PCNA experienced more distant metastasis (p=0.005). Univariate analysis showed that clinical staging, level of cyclinD1 and CEA were correlated with OS (p<0.05). Conclusions: Biological markers may be helpful in predicting the clinical outcome and prognosis for R0 resected gastric cancer patients. Further study are needed to confirm their clinical significance.

No significant financial relationships to disclose.

Comparison of cisplatin (CDDP) and radiation (RT) to cetuximab (C) and RT for locally advanced head and neck cancer (LAHNC): A preliminary analysis

6042

Background: Both concurrent CDDP/RT and C/RT have been shown in randomized trials to yield superior disease control compared to RT alone in LAHNC, but no randomized trial has compared them. We evaluated our center's experience with these regimens. Methods: From 3/1/06 - 4/1/08, 175 patients were retrospectively identified who received definitive treatment for LAHNC with CDDP (planned total dose 100 mg/m2 Q3 weeks X 3) and RT (n = 125) or C (400 mg/m2 load; 250 mg/m2 weekly) and RT (n = 50). Patients who received prior RT, additional systemic therapy, and/or surgery to the primary site were excluded. C was given for the following reasons: auditory 30%, renal 4%, cardiac 2%, performance status 18%, patient choice 16%, neuropathy 4%, unknown 2%, and a combination of factors 24%. The median age: CDDP group 56, 6% >71; C group 66.5, 40% >71. Additional CDDP and C features: male sex, 86 v 78%; stage IV, 70 v 68%; and oropharynx, 78 v 70%. Median RT dose (70 Gy), RT length (46 days), and Karnofsky performance status (KPS) (90%) were the same; alcohol/tobacco use was similar. Results: At a median follow up of 18.7 months, with death without local failure (LF) as a competing risk, the 18 month LF incidence rate was 2.5% in the CDDP group and 43.3% in the C group (p < 0.0001), with the latest event occurring at 16.5 months. The 18 month disease-free survival (DFS) and overall survival (OS) rates were 85.7 v 40.9%, and 96.8 v 73.1%, in favor of CDDP (p < 0.0001 for both). Initially, 21 variables were assessed for significance, and when Cox proportional hazards model was used for multivariate analysis to address prognostic imbalances, treatment with CDDP still predicted for improved LF, DFS, and OS (p < 0.0001 for LF and DFS; p = 0.0017 for OS). For OS analysis, the concordance probability estimates were .67 for using drug choice alone and .80 for using drug choice, T stage, RT dose, and KPS. Conclusions: CDDP/RT and C/RT were used to treat somewhat different populations with LAHNC. The observed superiority of CDDP/RT compared to C/RT in LF, DFS, and OS may reflect patient selection issues. However, preliminary multivariate modeling suggests that CDDP/RT remains the preferred option for fit patients pending further analyses and prospective studies comparing these regimens.

[Table: see text]

Cellular magnetic resonance imaging: potential for use in assessing aspects of cardiovascular disease

There is rapidly increasing interest in the use of magnetic resonance imaging (MRI) to track cell migration in vivo. Iron oxide MR contrast agents can be detected at micromolar concentrations of iron, and offer sufficient sensitivity for T2*-weighted imaging. Cellular MRI shows potential for assessing aspects of cardiovascular disease. Labeling in vivo and tracking macrophages using iron oxide nanoparticles has been a goal for cellular MRI because macrophages play a pivotal role in the pathophysiology of many human diseases, including atherosclerosis. Cellular MRI has also been using to track transplanted therapeutic cells in myocardial regeneration. This review looked at iron oxide nanoparticles, methods of cell labeling, image acquisition techniques and limitations encountered for visualization. Particular attention was paid to stem cells and macrophages for the cardiovascular system.

Superparamagnetic iron oxide nanoparticle-labeled cells as an effective vehicle for tracking the GFP gene marker using magnetic resonance imaging

BACKGROUND

Detection of a gene using magnetic resonance imaging (MRI) is hindered by the magnetic resonance (MR) targeting gene technique. Therefore it may be advantageous to image gene-expressing cells labeled with superparamagnetic iron oxide (SPIO) nanoparticles by MRI.

METHODS

The GFP-R3230Ac (GFP) cell line was incubated for 24 h using SPIO nanoparticles at a concentration of 20 microg Fe/mL. Cell samples were prepared for iron content analysis and cell function evaluation. The labeled cells were imaged using fluorescent microscopy and MRI.

RESULTS

SPIO was used to label GFP cells effectively, with no effects on cell function and GFP expression. Iron-loaded GFP cells were successfully imaged with both fluorescent microscopy and T2*-weighted MRI. Prussian blue staining showed intracellular iron accumulation in the cells. All cells were labeled (100% labeling efficiency). The average iron content per cell was 4.75+/-0.11 pg Fe/cell (P<0.05 versus control).

DISCUSSION

This study demonstrates that the GFP expression of cells is not altered by the SPIO labeling process. SPIO-labeled GFP cells can be visualized by MRI; therefore, GFP, a gene marker, was tracked indirectly with the SPIO-loaded cells using MRI. The technique holds promise for monitoring the temporal and spatial migration of cells with a gene marker and enhancing the understanding of cell- and gene-based therapeutic strategies.

[Studies on immunoprotection in mice after immunization with Schistosoma japonicum 22.6 kDa recombinant protein]

AIM

To evaluate the immunoprotective effect of Schistosoma japonicum recombinant 22.6 kDa (rSj22.6) and Sj22.6/Sj26 GST fusion protein.

METHODS

The Sj22.6/Sj26 GST fusion protein was prepared by affinity chromatography using glutathione Sepharose 4B. The purified rSj22.6 could be cleaved easily from the fusion protein with Thrombin. 17 and 12 mice immunized with rSj22.6 and Sj22.6/Sj26 GST separately were each challenged with 40 +/- 1 S. japonicum cercariae.

RESULTS

In BALB/c mice, the rSj22.6 and Sj22.6/Sj26 GST could induce 32.1 (P < 0.005) and 34.9% (P < 0.02) worm reduction, respectively, as well as 28.4% (P < 0.02) and 45.1% (P < 0.005) total egg reduction, respectively.

CONCLUSION

Bpth rSj22.6 and Sj22.6/Sj26 GST fusion protein are partially effective against S. japonicum.

Morphology-controlled synthesis and a comparative study of the physical properties of SnO2 nanostructures: from ultrathin nanowires to ultrawide nanobelts

Controlled synthesis of one-dimensional materials, such as nanowires and nanobelts, is of vital importance for achieving the desired properties and fabricating functional devices. We report a systematic investigation of the vapor transport growth of one-dimensional SnO(2) nanostructures, aiming to achieve precise morphology control. SnO(2) nanowires are obtained when SnO(2) mixed with graphite is used as the source material; adding TiO(2) into the source reliably leads to the formation of nanobelts. Ti-induced modification of crystal surface energy is proposed to be the origin of the morphology change. In addition, control of the lateral dimensions of both SnO(2) nanowires (from approximately 15 to approximately 115 nm in diameter) and nanobelts (from approximately 30 nm to approximately 2 microm in width) is achieved by adjusting the growth conditions. The physical properties of SnO(2) nanowires and nanobelts are further characterized and compared using room temperature photoluminescence, resonant Raman scattering, and field emission measurements.