Publications by authors named "Sophie Laurent"

218 Publications

A new method of extracting polyphenols from honey using a biosorbent compared to the commercial resin amberlite XAD2.

J Sep Sci 2021 Mar 4. Epub 2021 Mar 4.

NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, Mons, Belgium.

A new extraction method of polyphenols from honey using a biodegradable resin was developed and compared with the common commercial resin amberlite XAD2. For this purpose, three honey samples of Algerian origin were selected for the different physicochemical and biochemical parameters study. After extraction of the target compounds by both resins, the polyphenol content was determined, the antioxidant activity was tested, and liquid chromatography-mass spectrometry analyses were performed for identification and quantification. The results showed that physicochemical and biochemical parameters meet the norms of the International Honey Commission, and the H1 sample seemed to be of high quality. The optimal conditions of extraction by biodegradable resin were a pH of 3, an adsorption dose of 40 g/L, a contact time of 50 min, an extraction temperature of 60°C, and no stirring. The regeneration and reuse number of both resins was three cycles. The polyphenol contents demonstrated a higher extraction efficiency of biosorbent than of XAD2, especially in H1. Liquid chromatography-mass spectrometry analyses allowed for the identification and quantification of 15 compounds in the different honey samples extracted using both resins and the most abundant compound was 3,4,5-trimethoxybenzoic acid. In addition, the biosorbent extracts showed stronger antioxidant activities than the XAD2 extracts.
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http://dx.doi.org/10.1002/jssc.202001221DOI Listing
March 2021

Mn Complexes with Pyclen-Based Derivatives as Contrast Agents for Magnetic Resonance Imaging: Synthesis and Relaxometry Characterization.

Inorg Chem 2021 Mar 24;60(6):3604-3619. Epub 2021 Feb 24.

General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, 7000 Mons, Belgium.

Magnetic resonance imaging (MRI) has a leading place in medicine as an imaging tool of high resolution for anatomical studies and diagnosis of diseases, in particular for soft tissues that cannot be accessible by other modalities. Many research works are thus focused on improving the images obtained with MRI. This technique has indeed poor sensitivity, which can be compensated by using a contrast agent (CA). Today, the clinically approved CAs on market are solely based on gadolinium complexes that may induce nephrogenic systemic fibrosis for patients with kidney failure, whereas more recent studies on healthy rats also showed Gd retention in the brain. Consequently, researchers try to elaborate other types of safer MRI CAs like manganese-based complexes. In this context, the synthesis of Mn complexes of four 12-membered pyridine-containing macrocyclic ligands based on the pyclen core was accomplished and described herein. Then, the properties of these Mn(II) complexes were studied by two relaxometric methods, O NMR spectroscopy and H NMR dispersion profiles. The time of residence (τ) and the number of water molecules () present in the inner sphere of coordination were determined by these two experiments. The efficacy of the pyclen-based Mn(II) complexes as MRI CAs was evaluated by proton relaxometry at a magnetic field intensity of 1.41 T near those of most medical MRI scanners (1.5 T). Both the O NMR and the nuclear magnetic relaxation dispersion profiles indicated that the four hexadentate ligands prepared herein left one vacant coordination site to accommodate one water molecule, rapidly exchanging, in around 6 ns. Furthermore, it has been shown that the presence of an additional amide bond formed when the paramagnetic complex is conjugated to a molecule of interest does not alter the inner sphere of coordination of Mn, which remains monohydrated. These complexes exhibit relaxivities, large enough to be used as clinical MRI CAs (1.7-3.4 mM·s, at 1.41 T and 37 °C).
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http://dx.doi.org/10.1021/acs.inorgchem.0c03120DOI Listing
March 2021

Gold nanoparticle-mediated bubbles in cancer nanotechnology.

J Control Release 2021 Feb 16;330:49-60. Epub 2020 Dec 16.

Nano Drug Delivery Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran. Electronic address:

Microbubbles (MBs) have been extensively investigated in the field of biomedicine for the past few decades. Ultrasound and laser are the most frequently used sources of energy to produce MBs. Traditional acoustic methods induce MBs with poor localized areas of action. A high energy level is required to generate MBs through the focused continuous laser, which can be harmful to healthy tissues. As an alternative, plasmonic light-responsive nanoparticles, such as gold nanoparticles (AuNPs), are preferably used with continuous laser to decrease the energy threshold and reduce the bubbles area of action. It is also well-known that the utilization of the pulsed lasers instead of the continuous lasers decreases the needed AuNPs doses as well as laser power threshold. When well-confined bubbles are generated in biological environments, they play their own unique mechanical and optical roles. The collapse of a bubble can mechanically affect its surrounding area. Such a capability can be used for cargo delivery to cancer cells and cell surgery, destruction, and transfection. Moreover, the excellent ability of light scattering makes the bubbles suitable for cancer imaging. This review firstly provides an overview of the fundamental aspects of AuNPs-mediated bubbles and then their emerging applications in the field of cancer nanotechnology will be reviewed. Although the pre-clinical studies on the AuNP-mediated bubbles have shown promising data, it seems that this technique would not be applicable to every kind of cancer. The clinical application of this technique may basically be limited to the good accessible lesions like the superficial, intracavity and intraluminal tumors. The other essential challenges against the clinical translation of AuNP-mediated bubbles are also discussed.
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http://dx.doi.org/10.1016/j.jconrel.2020.12.022DOI Listing
February 2021

Antifungal potential of extracts, fractions and compounds from (Annonaceae) and (Rubiaceae).

Nat Prod Res 2020 Nov 27:1-5. Epub 2020 Nov 27.

Laboratory No. 3 of Organic Chemistry, Department of Organic Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.

Phytochemical study of afforded an alkaloid, 8,9-dimethoxy-5-phenanthridin-6-one (), isolated and characterised (assignment of H and C NMR) for the first time from a natural source along with two flavonoids, (2S)-5-hydroxy-7,8-dimethoxyflavanone () and (2S)-7-hydroxy-5-methoxy-6,8-dimethylflavone (). Clethric acid (), oleanoic acid (), β-sitosterol 3-O-β-D-glucopyranoside (), β-sitosterol palmitate () and a mixture of stigmasterol () and β-sitosterol () were isolated from . The structures of these compounds were elucidated using modern spectroscopic techniques including1D and 2D Nuclear Magnetic Resonance (NMR) Spectroscopy (H, C, H-H COSY, HSQC, HMBC) and Mass Spectrometry. Some fractions and compounds from exhibited good antifungal activity against clinical isolates and standard strains of yeast species of and genera while extracts from displayed weak antifungal activity. The results obtained show that could be a potential source of antifungal drugs.
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http://dx.doi.org/10.1080/14786419.2020.1828409DOI Listing
November 2020

Hepatocarcinoma Induces a Tumor Necrosis Factor-Dependent Kupffer Cell Death Pathway That Favors Its Proliferation Upon Partial Hepatectomy.

Front Oncol 2020 16;10:547013. Epub 2020 Oct 16.

Institute for Medical Immunology, Université Libre de Bruxelles, Brussels, Belgium.

Partial hepatectomy (PH) is the main treatment for early-stage hepatocellular carcinoma (HCC). Yet, a significant number of patients undergo recursion of the disease that could be linked to the fate of innate immune cells during the liver regeneration process. In this study, using a murine model, we investigated the impact of PH on HCC development by bioluminescence imaging and flow cytometry. While non-resected mice were able to control and reject orthotopic implanted Hepa1-6 hepatocarcinoma cells, resected liver underwent an increased tumoral proliferation. This phenomenon was associated with a PH-induced reduction in the number of liver-resident macrophages, i.e., Kupffer cells (KC). Using a conditional ablation model, KC were proved to participate in Hepa1-6 rejection. We demonstrated that in the absence of Hepa1-6, PH-induced KC number reduction was dependent on tumor necrosis factor-alpha (TNF-α), receptor-interacting protein kinase (RIPK) 3, and caspase-8 activation, whereas interleukin (IL)-6 acted as a KC pro-survival signal. In mice with previous Hepa1-6 encounter, the KC reduction switched toward a TNF-α-RIPK3-caspase-1 activation. Moreover, KC disappearance associated with caspase-1 activity induced the recruitment of monocyte-derived cells that are beneficial for tumor growth, while caspase-8-dependent reduction did not. In conclusion, our study highlights the importance of the TNF-α-dependent death pathway induced in liver macrophages following partial hepatectomy in regulating the antitumoral immune responses.
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http://dx.doi.org/10.3389/fonc.2020.547013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7597592PMC
October 2020

VCAM-1 Target in Non-Invasive Imaging for the Detection of Atherosclerotic Plaques.

Biology (Basel) 2020 Oct 29;9(11). Epub 2020 Oct 29.

Laboratory of Cardiology, Faculty of Medicine and Pharmacy, Université de Mons, 7000 Mons, Belgium.

Atherosclerosis is a progressive chronic arterial disease characterised by atheromatous plaque formation in the intima of the arterial wall. Several invasive and non-invasive imaging techniques have been developed to detect and characterise atherosclerosis in the vessel wall: anatomic/structural imaging, functional imaging and molecular imaging. In molecular imaging, vascular cell adhesion molecule-1 (VCAM-1) is a promising target for the non-invasive detection of atherosclerosis and for the assessment of novel antiatherogenic treatments. VCAM-1 is an adhesion molecule expressed on the activated endothelial surface that binds leucocyte ligands and therefore promotes leucocyte adhesion and transendothelial migration. Hence, for several years, there has been an increase in molecular imaging methods for detecting VCAM-1 in MRI, PET, SPECT, optical imaging and ultrasound. The use of microparticles of iron oxide (MPIO), ultrasmall superparamagnetic iron oxide (USPIO), microbubbles, echogenic immunoliposomes, peptides, nanobodies and other nanoparticles has been described. However, these approaches have been tested in animal models, and the remaining challenge is bench-to-bedside development and clinical applicability.
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http://dx.doi.org/10.3390/biology9110368DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7692297PMC
October 2020

Control of Biological Hazards in Insect Processing: Application of HACCP Method for Yellow Mealworm () Powders.

Foods 2020 Oct 24;9(11). Epub 2020 Oct 24.

INRAe, Oniris, Secalim UMR 1014, route de Gachet, CS 40706, 44307 Nantes, France.

Entomophagy has been part of human diets for a long time in a significant part of the world, but insects are considered to be a novel food everywhere else. It would appear to be a strategic alternative in the future of human diet to face the challenge of ensuring food security for a growing world population, using more environmentally sustainable production systems than those required for the rearing of other animals. , called yellow mealworm, is one of the most interesting insect species in view of mass rearing, and can be processed into a powder that ensures a long shelf life for its use in many potential products. When considering insects as food or feed, it is necessary to guarantee their safety. Therefore, manufacturers must implement a Hazard Analysis Critical Control plan (HACCP), to limit risks for consumers' health. The aim of this case study was to develop a HACCP plan for larvae powders for food in a risk-based approach to support their implementation in industry. Specific purposes were to identify related significant biological hazards and to assess the efficiency of different manufacturing process steps when used as Critical Control Points. Then, combinations of four different processes with four potential uses of powders by consumers in burger, protein shake, baby porridge, and biscuits were analyzed with regard to their safety.
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http://dx.doi.org/10.3390/foods9111528DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7690899PMC
October 2020

Myeloid tumor necrosis factor and heme oxygenase-1 regulate the progression of colorectal liver metastases during hepatic ischemia-reperfusion.

Int J Cancer 2021 Mar 19;148(5):1276-1288. Epub 2020 Oct 19.

Institut d'Immunologie Médicale, Université Libre de Bruxelles, Belgium.

The liver ischemia-reperfusion (IR) injury that occurs consequently to hepatic resection performed in patients with metastases can lead to tumor relapse for not fully understood reasons. We assessed the effects of liver IR on tumor growth and the innate immune response in a mouse model of colorectal (CR) liver metastasis. Mice subjected to liver ischemia 2 days after intrasplenic injection of CR carcinoma cells displayed a higher metastatic load in the liver, correlating with Kupffer cells (KC) death through the activation of receptor-interating protein 3 kinase (RIPK3) and caspase-1 and a recruitment of monocytes. Interestingly, the immunoregulatory mediators, tumor necrosis factor-α (TNF-α) and heme oxygenase-1 (HO-1) were strongly upregulated in recruited monocytes and were also expressed in the surviving KC following IR. Using TNF LysM mice, we showed that TNF deficiency in macrophages and monocytes favors tumor progression after IR. The antitumor effect of myeloid cell-derived TNF involved direct tumor cell apoptosis and a reduced expression of immunosuppressive molecules such as transforming growth factor-β, interleukin (IL)-10, inducible nitric oxyde synthase (iNOS), IL-33 and HO-1. Conversely, a monocyte/macrophage-specific deficiency in HO-1 (HO-1 LysM ) or the blockade of HO-1 function led to the control of tumor progression post-liver IR. Importantly, host cell RIPK3 deficiency maintains the KC number upon IR, inhibits the IR-induced innate cell recruitment, increases the TNF level, decreases the HO-1 level and suppresses the tumor outgrowth. In conclusion, tumor recurrence in host undergoing liver IR is associated with the death of antitumoral KC and the recruitment of monocytes endowed with immunosuppressive properties. In both of which HO-1 inhibition would reinforce their antitumoral activity.
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http://dx.doi.org/10.1002/ijc.33334DOI Listing
March 2021

Development of an LDL Receptor-Targeted Peptide Susceptible to Facilitate the Brain Access of Diagnostic or Therapeutic Agents.

Biology (Basel) 2020 Jul 11;9(7). Epub 2020 Jul 11.

NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, Avenue Maistriau 19, Mendeleïev Building, B-7000 Mons, Belgium.

Blood-brain barrier (BBB) crossing and brain penetration are really challenging for the delivery of therapeutic agents and imaging probes. The development of new crossing strategies is needed, and a wide range of approaches (invasive or not) have been proposed so far. The receptor-mediated transcytosis is an attractive mechanism, allowing the non-invasive penetration of the BBB. Among available targets, the low-density lipoprotein (LDL) receptor (LDLR) shows favorable characteristics mainly because of the lysosome-bypassed pathway of LDL delivery to the brain, allowing an intact discharge of the carried ligand to the brain targets. The phage display technology was employed to identify a dodecapeptide targeted to the extracellular domain of LDLR (ED-LDLR). This peptide was able to bind the ED-LDLR in the presence of natural ligands and dissociated at acidic pH and in the absence of calcium, in a similar manner as the LDL. In vitro, our peptide was endocytosed by endothelial cells through the caveolae-dependent pathway, proper to the LDLR route in BBB, suggesting the prevention of its lysosomal degradation. The in vivo studies performed by magnetic resonance imaging and fluorescent lifetime imaging suggested the brain penetration of this ED-LDLR-targeted peptide.
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http://dx.doi.org/10.3390/biology9070161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7407834PMC
July 2020

Novel Polymeric Micelles-Coated Magnetic Nanoparticles for In Vivo Bioimaging of Liver: Toxicological Profile and Contrast Enhancement.

Materials (Basel) 2020 Jun 15;13(12). Epub 2020 Jun 15.

Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095 Bucharest, Romania.

Magnetic nanoparticles are intensively studied for magnetic resonance imaging (MRI) as contrast agents but yet there remained some gaps regarding their toxicity potential and clinical implications of their biodistribution in organs. This study presents the effects induced by magnetite nanoparticles encapsulated in polymeric micelles (MNP-DSPE-PEG) on biochemical markers, metabolic functions, and MRI signal in CD1 mice liver. Three groups of animals, one control and the other ones injected with a suspension of five, respectively, 15 mg Fe/kg bw nanoparticles, were monitored up to 14 days. The results indicated the presence of MNP-DSPE-PEG in the liver in the first two days of the experiment. The most significant biochemical changes also occurred in the first 3 days after exposure when the most severe histological changes were observed. The change of the MRI signal intensity on the T2-weighted images and increased transverse relaxation rates R in the liver were observed after the first minutes from the nanoparticle administration. The study shows that the alterations of biomarkers level resulting from exposure to MNP-DSPE-PEG are restored in time in mice liver. This was associated with a significant contrast on T2-weighted images and made us conclude that these nanoparticles might be potential candidates for use as a contrast agent in liver medical imaging.
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http://dx.doi.org/10.3390/ma13122722DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7345181PMC
June 2020

Heterophynone and methyl ester of Colic acid, two new compounds with antimicrobial activity from (Sterculiaceae).

Nat Prod Res 2020 Jun 12:1-10. Epub 2020 Jun 12.

Laboratory of NMR and Molecular Imaging, Department of General, Organic Chemistry and Biochemistry, Univerisy of Mons, Mons, Belgium.

The ethyl acetate fraction, the stem bark and the residual methanolic extracts from the leaves of (Sterculiaceae) led to the isolation of two new compounds: Heterophynone () and methyl ester of Colic acid (), along with four known triterpenes: betulinic acid (), oleanolic acid (), ursolic acid () and chletric acid (). Structures of compounds were established by different spectroscopic methods that included 1D and 2D NMR experiment. The antimicrobial activity of isolated compounds was evaluated against two yeasts, NR 29456 and 1415; and five Gram-positive bacterial, , NR 46003, NR46374 and HM 601). Among tested compounds, Heterophynone was found to be the most active with significant antimicrobial activity against (MIC = 7.82 μg/mL and MBC = 62.5 μg/mL) and good activity against NR 29456 (MIC = 62.5 μg/mL).
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http://dx.doi.org/10.1080/14786419.2020.1777412DOI Listing
June 2020

Anti-Inflammatory and Analgesic Effect of Arachic Acid Ethyl Ester Isolated from Propolis.

Biomed Res Int 2020 3;2020:8797284. Epub 2020 May 3.

Department of Biological Sciences, Faculty of Science, University of Ngaoundéré, P.O. Box 454, Ngaoundéré, Cameroon.

Inflammatory diseases are a real public health problem worldwide. Many synthetic drugs used in the treatment of inflammatory diseases such as steroidal anti-inflammatory drugs, nonsteroidal anti-inflammatory drugs (NSAIDs) and immunosuppressive drugs have harmful side effects. However, there are natural products like propolis, which is traditionally used in the treatment of pain. The objective of this work was to evaluate the anti-inflammatory and analgesic activities of the ethyl ester of arachic acid, a compound isolated from Cameroonian propolis. The ethyl ester of arachic acid was isolated by chromatography of the ethanolic extract of propolis harvested at Tala-Mokolo (Far North Region of Cameroon) and identified by nuclear magnetic resonance (NMR) spectra and the H-H correlated spectroscopy. The anti-inflammatory and analgesic properties of oral administration of arachic acid ethyl ester (12.5, 25.0, and 50.0 mg/kg bw) were evaluated using carrageenan-induced paw edema, xylene-induced ear edema, cotton pellets-induced granuloma formation, and hot plate test in rat. Arachic acid ethyl ester produced maximum inhibition at 50.0 mg/kg for carrageenan-induced paw edema (62.5%), xylene-induced ear edema (54.5%), cotton pellet-induced granuloma (47.4%), and increased mean latency for hot plate test in rats. These results show clearly that the arachic acid ethyl ester has acute and chronic anti-inflammatory properties as well as central analgesic properties. This justifies the use of propolis in the treatment of pain in traditional medicine.
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http://dx.doi.org/10.1155/2020/8797284DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7222486PMC
March 2021

Multi-Level Vertebroplasty for 6 or More Painful Osteoporotic Vertebral Body Compression Fractures Performed in the Same Procedural Setting: A Safety and Efficacy Report in Cancer Patients.

Cardiovasc Intervent Radiol 2020 Jul 7;43(7):1041-1048. Epub 2020 May 7.

Department Interventional Radiology Unit, Imaging Department, Gustave Roussy Cancer Campus, 114 rue Edouard Vaillant, 94805, Villejuif, France.

Purpose: To assess safety and efficacy of multi-level vertebroplasty, when treating 6 or more levels in the same procedural setting for the management of osteoporotic vertebral compression fractures (oVCF) in cancer patients.

Materials And Methods: Single institution retrospective review from 2015 to 2019 of patients treated for multi-level oVCF in a single session procedural setting by vertebroplasty of 6 or more levels. Procedure outcomes collected included procedural complications, pre- and 4 week post-procedure pain score by numeric rating scale, opioid usage, and vertebral height changes.

Results: In total, 197 vertebral levels were treated in 24 procedures (mean 8.2 ± 1.8 levels). Mean procedure duration was 167 + / - 41 min, and mean postoperative hospitalization duration was 2.1 + / - 1.9 days. Four grade I or II complications occurred according to CIRSE classification. Two patients had a symptomatic pulmonary cement embolism; although there was no statistical difference between pre- and postoperative mean blood saturation (95.9 + / - 1.7% and 94.8 + / - 2.0%, respectively, p = 0.066). Pain score significantly improved after treatment (6.5 ± 1.3 vs 3.2 + / - 1.4, p < 0.0001) with a mean decrease of 3.3 (51%). Post-procedure daily opioid use also significantly improved (mean 35.8 + / - 36.8 mg/24 h vs 18.5 + / - 27.8 mg/24 h, p = 0.0089), with a mean decrease of 17.3 mg/24 h (48%). Refracture was found in 2 of 105 levels treated (1.9%), and no difference was found in thoraco-lumbar height and angulation. Five patients experienced new painful fractures at a non-treated level.

Conclusion: Multi-level vertebroplasty for 6 or more levels is a safe and effective treatment for the management of multi-level oVCF in cancer patients.
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http://dx.doi.org/10.1007/s00270-020-02480-yDOI Listing
July 2020

Influence of Experimental Parameters of a Continuous Flow Process on the Properties of Very Small Iron Oxide Nanoparticles (VSION) Designed for T-Weighted Magnetic Resonance Imaging (MRI).

Nanomaterials (Basel) 2020 Apr 15;10(4). Epub 2020 Apr 15.

Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, B-7000 Mons, Belgium.

This study reports the development of a continuous flow process enabling the synthesis of very small iron oxide nanoparticles (VSION) intended for T-weighted magnetic resonance imaging (MRI). The influence of parameters, such as the concentration/nature of surfactants, temperature, pressure and the residence time on the thermal decomposition of iron(III) acetylacetonate in organic media was evaluated. As observed by transmission electron microscopy (TEM), the diameter of the resulting nanoparticle remains constant when modifying the residence time. However, significant differences were observed in the magnetic and relaxometric studies. This continuous flow experimental setup allowed the production of VSION with high flow rates (up to 2 mL·min), demonstrating the efficacy of such process compared to conventional batch procedure for the scale-up production of VSION.
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http://dx.doi.org/10.3390/nano10040757DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7221927PMC
April 2020

Molecular Imaging of Galectin-1 Expression as a Biomarker of Papillary Thyroid Cancer by Using Peptide-Functionalized Imaging Probes.

Biology (Basel) 2020 Mar 14;9(3). Epub 2020 Mar 14.

Department of General, Organic and Biomedical Chemistry, UMONS, Avenue Victor Maistriau 19, 7000 Mons, Belgium.

Thyroid cancers are the most frequent endocrine cancers and their incidence is increasing worldwide. Thyroid nodules occur in over 19-68% of the population, but only 7-15% of them are diagnosed as malignant. Diagnosis relies on a fine needle aspiration biopsy, which is often inconclusive and about 90% of thyroidectomies are performed for benign lesions. Galectin-1 has been proposed as a confident biomarker for the discrimination of malignant from benign nodules. We previously identified by phage display two peptides (P1 and P7) targeting galectin-1, with the goal of developing imaging probes for non-invasive diagnosis of thyroid cancer. The peptides were coupled to ultra-small superparamagnetic particles of iron oxide (USPIO) or to a near-infrared dye (CF770) for non-invasive detection of galectin-1 expression in a mouse model of papillary thyroid cancer (PTC, as the most frequent one) by magnetic resonance imaging and fluorescence lifetime imaging. The imaging probes functionalized with the two peptides presented comparable image enhancement characteristics. However, those coupled to P7 were more favorable, and showed decreased retention by the liver and spleen (known for their galectin-1 expression) and high sensitivity (75%) and specificity (100%) of PTC detection, which confirm the aptitude of this peptide to discriminate human malignant from benign nodules (80% sensitivity, 100% specificity) previously observed by immunohistochemistry.
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http://dx.doi.org/10.3390/biology9030053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7150867PMC
March 2020

Correction to: Preventive Vertebroplasty for Long-Term Consolidation of Vertebral Metastases.

Cardiovasc Intervent Radiol 2020 May;43(5):807

Interventional Radiology Unit, Imaging Department, Gustave Roussy Cancer Campus, 114 rue Edouard Vaillant, 94805, Villejuif, France.

In the original article, the following author name was incorrectly published and the corrected name is given below.
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http://dx.doi.org/10.1007/s00270-020-02445-1DOI Listing
May 2020

Modulation of adiponectin receptors AdipoR1 and AdipoR2 by phage display-derived peptides in and models.

J Drug Target 2020 Aug-Sep;28(7-8):831-851. Epub 2020 Jan 10.

Department of General, Organic and Biomedical Chemistry, Faculty of Medicine and Pharmacy, University of Mons - UMONS, Mons, Belgium.

Type 2 diabetes (T2D) is often linked to metabolic syndrome, which assembles various risk factors related to obesity. Plasma levels of adiponectin are decreased in T2D and obese subjects. Aiming to develop a peptide able to bind adiponectin receptors and modulate their signalling pathways, a 12-amino acid sequence homologous in AdipoR1/R2 has been targeted by phage display with a linear 12-mer peptide library. The selected peptide P17 recognises AdipoR1/R2 expressed by skeletal muscle, liver and pancreatic islets. In HepaRG and C2C12 cells, P17 induced the activation of AMPK (AMPKα-pT172) and the expression of succinate dehydrogenase and glucokinase; no cytotoxic effects were observed on HepaRG cells. In db/db mice, P17 promoted body weight and glycaemia stabilisation, decreased plasma triglycerides to the range of healthy mice and increased adiponectin (in high fat-fed mice) and insulin (in chow-fed mice) levels. It restored to the range of healthy mice the tissue levels and subcellular distribution of AdipoR1/R2, AMPKα-pT172 and PPARα-pS12. In liver, P17 reduced steatosis and apoptosis. The docking of P17 to AdipoR is reminiscent of the binding mechanism of adiponectin. To conclude, we have developed an AdipoR1/AdipoR2-targeted peptide that modulates adiponectin signalling pathways and has therapeutic relevance for T2D and obesity associated pathologies.
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http://dx.doi.org/10.1080/1061186X.2019.1710840DOI Listing
January 2020

Silica Coated Iron/Iron Oxide Nanoparticles as a Nano-Platform for T Weighted Magnetic Resonance Imaging.

Molecules 2019 Dec 17;24(24). Epub 2019 Dec 17.

CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, F-31077 Toulouse CEDEX 4, France.

The growing concern over the toxicity of Gd-based contrast agents used in magnetic resonance imaging (MRI) motivates the search for less toxic and more effective alternatives. Among these alternatives, iron-iron oxide (Fe@FeOx) core-shell architectures have been long recognized as promising MRI contrast agents while limited information on their engineering is available. Here we report the synthesis of 10 nm large Fe@FeOx nanoparticles, their coating with a 11 nm thick layer of dense silica and functionalization by 5 kDa PEG chains to improve their biocompatibility. The nanomaterials obtained have been characterized by a set of complementary techniques such as infra-red and nuclear magnetic resonance spectroscopies, transmission electron microscopy, dynamic light scattering and zetametry, and magnetometry. They display hydrodynamic diameters in the 100 nm range, zetapotential values around -30 mV, and magnetization values higher than the reference contrast agent RESOVIST. They display no cytotoxicity against 1BR3G and HCT116 cell lines and no hemolytic activity against human red blood cells. Their nuclear magnetic relaxation dispersion (NMRD) profiles are typical for nanomaterials of this size and magnetization. They display high r relaxivity values and low r leading to enhanced r/r ratios in comparison with RESOVIST. All these data make them promising contrast agents to detect early stage tumors.
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http://dx.doi.org/10.3390/molecules24244629DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6943426PMC
December 2019

Tailored ultra-small Prussian blue-based nanoparticles for MRI imaging and combined photothermal/photoacoustic theranostics.

Chem Commun (Camb) 2019 Dec;55(98):14844-14847

Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris Sud Paris Saclay, 91405 Orsay, France.

Ultrasmall sub-10 nm nanoparticles of Prussian blue analogues incorporating GdIII ions at their periphery revealed longitudinal relaxivities above 40 mM-1 s-1 per GdIII regardless of the nature of the core and the polymer coating. Large T1-weighted contrast enhancements were achieved in addition to a highly efficient photothermal effect and in vivo photoacoustic imaging in tumors.
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http://dx.doi.org/10.1039/c9cc07116dDOI Listing
December 2019

Backbone Cleavages of Protonated Peptoids upon Collision-Induced Dissociation: Competitive and Consecutive B-Y and A-Y Reactions.

J Am Soc Mass Spectrom 2019 Dec 21;30(12):2726-2740. Epub 2019 Nov 21.

Organic Synthesis & Mass Spectrometry Laboratory, Interdisciplinary Center for Mass Spectrometry (CISMa), Center of Innovation and Research in Materials and Polymers (CIRMAP), University of Mons - UMONS, 23 Place du Parc, 7000, Mons, Belgium.

Mass spectrometric techniques and more particularly collision-induced dissociation (CID) experiments represent a powerful method for the determination of the primary sequence of (bio)molecules. However, the knowledge of the ion fragmentation patterns say the dissociation reaction mechanisms is a prerequisite to reconstitute the sequence based on fragment ions. Previous papers proposed that protonated peptoids dissociate following an oxazolone-ring mechanism starting from the O-protonation species and leading to high mass Y sequence ions. Here we revisit this backbone cleavage mechanism by performing CID and ion mobility experiments, together with computational chemistry, on tailor-made peptoids. We demonstrated that the B/Y cleavages of collisionally activated O-protonated peptoids must involve the amide nitrogen protonated structures as the dissociating species, mimicking the CID behavior of protonated peptides. Upon the nucleophilic attack of the oxygen atom of the N-terminal adjacent carbonyl group on the carbonyl carbon atom of the protonated amide, the peptoid ions directly dissociate to form an ion-neutral complex associating an oxazolone ion to the neutral truncated peptoid residue. Dissociation of the ion/neutral complex predominantly produces Y ions due to the high proton affinity of the secondary amide function characteristic of truncated peptoids. Whereas the production of Y ions from acetylated peptoids also involves the B/Y pathway, the observation of abundant Y ions from non-acetylated peptoid ions is shown in the present study to arise from an A-Y mechanism. The consecutive and competitive characters of the A-Y and the B/Y mechanisms are also investigated by drift time-aligned CID experiments.
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http://dx.doi.org/10.1007/s13361-019-02342-zDOI Listing
December 2019

MRI-based numerical modeling strategy for simulation and treatment planning of nanoparticle-assisted photothermal therapy.

Phys Med 2019 Oct 7;66:124-132. Epub 2019 Oct 7.

Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran. Electronic address:

Nanoparticle-assisted photothermal therapy (NPTT) has recently emerged as a promising alternative to traditional thermal therapy methods. Computational modeling for simulation and treatment planning of NPTT seems to be essential for clinical translation of this modality. Non-invasive identification of nanoparticle distribution within the tissue is a key perquisite for accurate prediction of NPTT in real conditions. In the present study, we have developed a magnetic resonance imaging (MRI)-based numerical modeling strategy for simulation and treatment planning of NPTT. To this end, we have utilized the core-shell γ-FeO@Au nanoparticle comprising a gold layer with plasmonic properties and a magnetic core that enables to track the location of this structure via MRI. The map of nanoparticle distribution in the tumor derived from T-weighted MR image was imported into a finite element simulation software, and Pennes bioheat equation and Arrhenius damage model were applied to simulate the temperature and damage distributions, respectively. The validation of the model developed herein was assessed by monitoring the superficial and the central temperature variations of the tumor in experiment. Both the numerical modeling and experimental study proved that a localized heating and then a focused damage could be achieved due to nanoparticle inclusion. There is quite satisfactory agreement between the numerical and experimental results. The model developed in this study has a good capability to be used as a promising planning method for NPTT of cancer.
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http://dx.doi.org/10.1016/j.ejmp.2019.10.002DOI Listing
October 2019

Synthesis and Relaxometric Characterization of New Poly[N,N-bis(3-aminopropyl)glycine] (PAPGly) Dendrons Gd-Based Contrast Agents and Their in Vivo Study by Using the Dynamic Contrast-Enhanced MRI Technique at Low Field (1 T).

Chem Biodivers 2019 Nov 29;16(11):e1900322. Epub 2019 Oct 29.

General, Organic and Biomedical Chemistry Unit, NMR and Molecular Imaging Laboratory, University of Mons, 19 avenue Maistriau, B-7000, Mons, Belgium.

The synthesis of poly[N,N-bis(3-aminopropyl)glycine] (PAPGly) dendrons Gd-based contrast agents (GdCAs) via an orthogonal protection of the different functional groups and an activation/coupling strategy wherein a specific number of synthetic steps add a generation to the existing dendron has been described. The aim of this protocol is to build up two different generations of dendrons (G-0 or dendron's core, and G-1) with peripheral NH groups to conjugate a 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3A) derivative and afterwards to chelate with Gd paramagnetic ions. These complexes, which have a well-defined molecular weight, are of relevance to MRI as an attempt to gain higher H relaxivity by slowing down the rotation of molecule compared to monomeric Gd(III) complexes used as contrast agents and to increase the number of paramagnetic centers present in one molecular structure. From the study of their water H longitudinal relaxation rate at different magnetic fields (NMRD, Nuclear Magnetic Relaxation Dispersion) and by evaluating the variable temperature O-NMR data we determined the parameters characterizing the water exchange rate and the rotational correlation time of each complex, both affecting H relaxivity. Furthermore, these two novel PAPGly GdCAs were objects of i) an in vivo study to determine their biodistributions in healthy C57 mice at several time points, and ii) the Dynamic Contrast-Enhanced MRI (DCE-MRI) approach to assess their contrast efficiency measured in the tumor region of C57BL/6 mice transplanted subcutaneously with B16-F10 melanoma cells. The aim of the comparison of these two dendrons GdCAs, having different molecular weights (MW), is to understand how MW and relaxivity may influence the contrast enhancement capabilities in vivo at low magnetic field (1 T). Significant contrast enhancement was observed in several organs (vessel, spleen and liver), already at 5 min post-injection, for the investigated CAs. Moreover, these CAs induced a marked contrast enhancement in the tumor region, thanks to the enhanced permeability retention effect of those macromolecular structures.
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http://dx.doi.org/10.1002/cbdv.201900322DOI Listing
November 2019

Gold nanomaterials as key suppliers in biological and chemical sensing, catalysis, and medicine.

Biochim Biophys Acta Gen Subj 2020 01 14;1864(1):129435. Epub 2019 Sep 14.

Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, United States.

Background: Gold nanoparticles (AuNPs) with unique physicochemical properties have received a great deal of interest in the field of biological, chemical and biomedical implementations. Despite the widespread use of AuNPs in chemical and biological sensing, catalysis, imaging and diagnosis, and more recently in therapy, no comprehensive summary has been provided to explain how AuNPs could aid in developing improved sensing and catalysts systems as well as medical settings.

Scope Of Review: The chemistry of Au-based nanosystems was followed by reviewing different applications of Au nanomaterials in biological and chemical sensing, catalysis, imaging and diagnosis by a number of approaches, and finally synergistic combination therapy of different cancers. Afterwards, the clinical impacts of AuNPs, future application of AuNPs, and opportunities and challenges of AuNPs application were also discussed.

Major Conclusions: AuNPs show exclusive colloidal stability and are considered as ideal candidates for colorimetric detection, catalysis, imaging, and photothermal transducers, because their physicochemical properties can be tuned by adjusting their structural dimensions achieved by the different manufacturing methods.

General Significance: This review provides some details about using AuNPs in sensing and catalysis applications as well as promising theranostic nanoplatforms for cancer imaging and diagnosis, and sensitive, non-invasive, and synergistic methods for cancer treatment in an almost comprehensive manner.
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http://dx.doi.org/10.1016/j.bbagen.2019.129435DOI Listing
January 2020

Preliminary studies of Ga-NODA-USPION-BBN as a dual-modality contrast agent for use in positron emission tomography/magnetic resonance imaging.

Nanotechnology 2020 Jan 13;31(1):015102. Epub 2019 Sep 13.

NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, 23 Place du Parc, B-7000, Mons, Belgium.

The aim of this study was to propose a new dual-modality nanoprobe for positron emission tomography/magnetic resonance imaging (PET/MRI) for the early diagnosis of breast cancer. For synthesis of the nanoprobe, polyethylene glycol-coated ultra-small superparamagnetic iron-oxide nanoparticles (USPION) armed with NODA-GA chelate and grafted with bombesin (BBN) were radiolabeled with Ga. After characterization, in vitro studies to evaluate the cell binding affinity of the nanoprobe were done by performing Perl's Prussian blue cell staining and MRI imaging. Finally, for in vivo studies, magnetic resonance images were taken in SCID mice bearing breast cancer tumor pre- and post-injection, and a multimodal nanoScan PET/computed tomography was used to perform preclinical imaging of the radiolabeled nanoparticles. Afterwards, a biodistribution study was done on sacrificed mice. The results showed that the highest r and r values were measured for USPIONs at 20 and 60 MHz, respectively. From the in vitro studies, the optical density of the cells after incubation increased with the increase of the iron concentration and the duration of incubation. However, the T values decreased when the iron concentration increased. Furthermore, from in vivo studies, the T and signal intensity decreased during the elapsed time post-injection in the tumor area. In this study, the in vitro studies showed that the affinity of cancer cells to nanoprobe increases meaningfully after conjugation with BBN, and also by increasing the duration of incubation and the iron concentration. Meanwhile, the in vivo results confirmed that the blood clearance of the nanoprobe happened during the first 120 min post-injection of the radiolabeled nanoprobe and also confirmed the targeting ability of that to a gastrin-releasing peptide receptor positive tumor.
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http://dx.doi.org/10.1088/1361-6528/ab4446DOI Listing
January 2020

Comparison of MRI Properties between Multimeric DOTAGA and DO3A Gadolinium-Dendron Conjugates.

Inorg Chem 2019 Oct 9;58(19):12798-12808. Epub 2019 Sep 9.

Institut de Chimie Moléculaire de Reims, CNRS UMR 7312 , Université de Reims Champagne-Ardenne URCA , F-51685 Reims Cedex 2 , France.

The inherent lack of sensitivity of MRI needs the development of new Gd contrast agents in order to extend the application of this technique to cellular imaging. For this purpose, two multimeric MR contrast agents obtained by peptidic coupling between an amido amine dendron and GdDOTAGA chelates (premetalation strategy, G1-4GdDOTAGA) or DO3A derivatives which then were postmetalated (G1-4GdDO3A) have been prepared. By comparison to the monomers, an increase of longitudinal relaxivity has been observed for both structures. Especially for G1-4GdDO3A, a marked increase is observed between 20 and 60 MHz. This structure differs from G1-4GdDOTAGA by an increased rigidity due to the aromatic linker between each chelate and the organic framework. This has the effect of limiting local rotational movements, which has a positive impact on relaxivity.
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http://dx.doi.org/10.1021/acs.inorgchem.9b01747DOI Listing
October 2019

Percutaneous Fixation by Internal Cemented Screws of the Sternum.

Cardiovasc Intervent Radiol 2020 Jan 3;43(1):103-109. Epub 2019 Sep 3.

Interventional Radiology Unit, Medical Imaging Department, Gustave Roussy - Cancer Center, 114 Rue Edouard Vaillant, 94805, Villejuif, France.

Purpose: To evaluate the feasibility, efficacy and safety of sternal percutaneous fixation by internal cemented screw (FICS) using fluoroscopy and/or CT needle guidance.

Materials And Methods: This retrospective single-center study analyzed 9 consecutive cancer patients managed with percutaneous FICS for sternal fracture fixation or osteolytic metastasis consolidation, from May 2014 to February 2019. Eastern Cooperative Oncology Group performance status, Numeric Pain Rating Scale (NPRS) and opioid use were studied preoperatively and postoperatively. Sternal images at last follow-up appointment were also collected.

Results: Among the 9 patients, 7 had a sternal fracture with 5 being displaced. The technical feasibility was 100%. Both NPRS score significantly decreased from 5.6/10 ± 2.8 to 1.1/10 ± 1.6, and analgesic consumption was significantly improved (p = 0.03) after intervention. No post-procedural complications requiring surgical correction or screw displacement occurred after a mean imaging follow-up that exceeded 1 year (mean follow-up duration, 401.8 days ± 305.8).

Conclusion: Image-guided sternal percutaneous FICS is feasible and safe. It reduces pain and analgesic consumption related to pathologic fracture of the sternum.
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http://dx.doi.org/10.1007/s00270-019-02334-2DOI Listing
January 2020

Simulation-guided photothermal therapy using MRI-traceable iron oxide-gold nanoparticle.

J Photochem Photobiol B 2019 Oct 22;199:111599. Epub 2019 Aug 22.

Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran. Electronic address:

Despite the immense benefits of nanoparticle-assisted photothermal therapy (NPTT) in cancer treatment, the limited method and device for detecting temperature during heat operation significantly hinder its overall progress. Development of a pre-treatment planning tool for prediction of temperature distribution would greatly improve the accuracy and safety of heat delivery during NPTT. Reliable simulation of NPTT highly relies on accurate geometrical model description of tumor and determining the spatial location of nanoparticles within the tissue. The aim of this study is to develop a computational modeling method for simulation of NPTT by exploiting the theranostic potential of iron oxide‑gold hybrid nanoparticles (IO@Au) that enable NPTT under magnetic resonance imaging (MRI) guidance. To this end, CT26 colon tumor-bearing mice were injected with IO@Au nanohybrid and underwent MR imaging. The geometrical model description of tumor and nanoparticle distribution map were obtained from MR image of the tumor and involved in finite element simulation of heat transfer process. The experimental measurement of tumor temperature confirmed the validity of the model to predict temperature distribution. The constructed model can help to predict temperature distribution during NPTT and then allows to optimize the heating protocol by adjusting the treatment parameters prior to the actual treatment operation.
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http://dx.doi.org/10.1016/j.jphotobiol.2019.111599DOI Listing
October 2019

Discrimination of Regioisomeric and Stereoisomeric Saponins from Aesculus hippocastanum Seeds by Ion Mobility Mass Spectrometry.

J Am Soc Mass Spectrom 2019 Nov 26;30(11):2228-2237. Epub 2019 Aug 26.

Organic Synthesis and Mass Spectrometry Laboratory (S2MOs), University of Mons, 23 Place du Parc, 7000, Mons, Belgium.

Modern mass spectrometry methods provide a huge benefit to saponin structural characterization, especially when combined with collision-induced dissociation experiments to obtain a partial description of the saponin (ion) structure. However, the complete description of the structures of these ubiquitous secondary metabolites remain challenging, especially since isomeric saponins presenting small differences are often present in a single extract. As a typical example, the horse chestnut triterpene glycosides, the so-called escins, comprise isomeric saponins containing subtle differences such as cis-trans ethylenic configuration (stereoisomers) of a side chain or distinct positions of an acetyl group (regioisomers) on the aglycone. In the present paper, the coupling of liquid chromatography and ion mobility mass spectrometry has been used to distinguish regioisomeric and stereoisomeric saponins. Ion mobility arrival time distributions (ATDs) were recorded for the stereoisomeric and regioisomeric saponin ions demonstrating that isomeric saponins can be partially separated using ion mobility on a commercially available traveling wave ion mobility (TWIMS) mass spectrometer. Small differences in the ATD can only be monitored when the isomeric saponins are separated with liquid chromatography prior to the IM-MS analysis. However, gas phase separation between stereoisomeric and regioisomeric saponin ions can be successfully realized, without any LC separation, on a cyclic ion mobility-enabled quadrupole time-of-flight (Q-cIM-oaToF) mass spectrometer. The main outcome of the present paper is that the structural analysis of regioisomeric and stereoisomeric natural compounds that represents a real challenge can take huge advantages of ion mobility experiments but only if increased ion mobility resolution is attainable.
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http://dx.doi.org/10.1007/s13361-019-02310-7DOI Listing
November 2019

Preventive Vertebroplasty for Long-Term Consolidation of Vertebral Metastases.

Cardiovasc Intervent Radiol 2019 Dec 23;42(12):1726-1737. Epub 2019 Aug 23.

Interventional Radiology Unit, Imaging Department, Gustave Roussy Cancer Campus, 114 rue Edouard Vaillant, 94805, Villejuif, France.

Introduction: To evaluate the long-term consolidation of vertebral metastases (VM) after preventive vertebroplasty (PV) and to report risk factors of pathological fracture despite PV.

Materials And Methods: Files of 100 consecutives cancer patients referred for PV of VM were retrospectively analyzed. We enumerated 215 VM at the time of the PV procedure (T0): 138 VM were considered at risk of pathological fracture and had PV (treated-VM), and 77 VM were not cemented. We compared the VM characteristics using the spine instability neoplastic score (SINS) at T0 and the rate of pathologic fracture between treated-VM and untreated-VM using Kaplan-Meier method. We analyzed risk factors of pathological fracture despite PV using treated-VM characteristics and quality of cement injection criteria.

Results: Despite a lower SINS value at T0 (p < 0.001), the rate of pathological fracture was significantly higher among untreated-VM compared to the treated-VM, (log-rank, p < 0.001). Major risk factors of fracture among treated-VM were: SINS value ≥ 8 (p < 0.012), mechanical pain (p = 0.001), osteolytic lesion (p = 0.033), metastatic vertebral body involvement > 50% with no collapse (p < 0.001) and unilateral posterior involvement by the vertebral metastasis (p = 0.024), Saliou score < 9 (p = 0.008), vertebral metastasis filling with cement < 50% (p = 0.007) and the absence of cement's contact with vertebral endplates (p = 0.014).

Conclusion: PV is long-term effective for consolidation of VM and must be discussed at the early diagnosed. Quality of cement injection matters, suggesting that techniques that improve the quantity and the quality of cement diffusion into the VM must be developed.
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http://dx.doi.org/10.1007/s00270-019-02314-6DOI Listing
December 2019

Embedding of superparamagnetic iron oxide nanoparticles into membranes of well-defined poly(ethylene oxide)-block-poly(ε-caprolactone) nanoscale magnetovesicles as ultrasensitive MRI probes of membrane bio-degradation.

J Mater Chem B 2019 07;7(30):4692-4705

Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, 19 avenue Maistriau B-7000 Mons, Belgium. and Center for Microscopy and Molecular Imaging, 8 rue Adrienne Bolland, B-6041 Charleroi, Belgium.

The present study reports the preparation of poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) polymer vesicles via a nanoprecipitation method and the loading of two different size hydrophobically coated ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles (a magnetic core size of 4.2 nm and 7.6 nm) into the membrane of these nanovesicles, whose thickness was measured precisely by small angle neutron scattering (SANS). Spherical nano-assemblies with a high USPIO payload and a diameter close to 150 nm were obtained as confirmed by dynamic light scattering (DLS), transmission electron microscopy (TEM) and cryo-TEM. The vesicular structure of these hybrid nano-assemblies was confirmed by multi-angle light scattering (MALS) measurements. Their magnetic properties were evaluated by T1 and T2 measurements (20 and 60 MHz) and by nuclear magnetic relaxation dispersion (NMRD) profiles. The size of USPIO entrapped in the membranes of PEO-b-PCL vesicles has a strong impact on their magnetic properties. It affects both their longitudinal and their transverse relaxivities and thus their magnetic resonance imaging (MRI) sensitivity. Acid-catalyzed hydrolysis of the PCL membrane also influences their relaxivities as shown by measurements carried out at pH 7 vs. pH 5. This property was used to monitor the membrane hydrolytic degradation in vitro, as a proof of concept of potential monitoring of drug delivery by nanomedicines in vivo and non-invasively, by MRI.
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http://dx.doi.org/10.1039/c9tb00909dDOI Listing
July 2019