Michèle Cottier

Long-term in vivo clearance of gadolinium-based AGuIX nanoparticles and their biocompatibility after systemic injection.

We previously reported the synthesis of gadolinium-based nanoparticles (NPs) denoted AGuIX (activation and guiding of irradiation by X-ray) NPs and demonstrated their potential as an MRI contrast agent and their efficacy as radiosensitizing particles during X-ray cancer treatment. Here we focus on the elimination kinetics of AGuIX NPs from the subcellular to whole-organ scale using original and complementary methods such as laser-induced breakdown spectroscopy (LIBS), intravital two-photon microscopy, inductively coupled plasma optical emission spectrometry (ICP-OES), transmission electron microscopy (TEM), and electrospray ionization mass spectrometry (ESI-MS). This combination of techniques allows the exact mechanism of AGuIX NPs elimination to be elucidated, including their retention in proximal tubules and their excretion as degraded or native NPs. Finally, we demonstrated that systemic AGuIX NP administration induced moderate and transient effects on renal function. These results provide useful and promising preclinical information concerning the safety of theranostic AGuIX NPs.

Accuracy and Feasibility of Electromagnetic Navigated Bronchoscopy under Nitrous Oxide Sedation for Pulmonary Peripheral Opacities: An Outpatient Study

Background: Recent studies have described the promising method of electromagnetic navigated bronchoscopy (ENB) for diagnosis of peripheral solitary nodules. However, they require general anaesthesia or intravenous sedation. We wanted to know if ENB could be applied more easily in outpatients. Objectives: We prospectively evaluated the accuracy and the feasibility of ENB under local anaesthesia and nitrous oxide/oxygen inhalation as unique sedation in outpatients. Methods: After mapping time, the bronchoscopic procedure was carried out under local anaesthesia and nitrous oxide/oxygen inhalation with the unique help of the ENB to confirm the right position of the extended working channel before sampling. The primary end point was the accuracy of ENB and the secondary end point was the feasibility in outpatients. Results: Among 54 screened patients, 53 completed the study protocol. The overall diagnostic success rate to diagnose malignancy was 71.4% in tumours of 28 mm in median size. ENB classified correctly peripheral lesions according to malignity in 41 cases (30 cases of cancer, 11 benign diagnosis) and failed in 12 cases (1 probable lung metastasis, 11 lung cancers). All patients but 1 were dismissed 1 h after the procedure and the tolerance of the procedure was excellent in all cases except 2 (agitation and anxiety). In two cases (4%) a pneumothorax was recorded, 1 requiring drainage with a chest tube during a short hospitalisation. Conclusions: ENB under nitrous oxide/oxygen sedation seems to be an accurate and safe procedure. In our series, it allowed us to obtain the diagnosis in 71.4% of the tumours, with a good tolerance and an outpatient strategy.

Prospective flow cytometric DNA analysis of hepatocellular carcinoma specimens collected by ultrasound‐guided fine needle aspiration

Background. The survival of 52 patients with hepatocellular carcinoma (HCC) seen during the last 4 years was analyzed prospectively on the basis of disease stage and nuclear DNA content.

Plastinated nasal model: a new concept of anatomically realistic cast.

BACKGROUND For many years, researchers have been interested in investigating airflow and aerosol deposition in the nasal cavities. The nasal airways appear to be a complex geometrical system. Thus, in vitro experimental studies are frequently conducted with a more or less biomimetic nasal replica. AIM This study is devoted to the development of an anatomically realistic nose model with bilateral nasal cavities, i.e. nasal anatomy, airway geometry and aerodynamic properties as close as possible to in vivo behaviour. METHODS A specific plastination technique of cephalic extremities was developed by the Anatomy Laboratory at the Saint-Etienne University in the last 10 years. The plastinated models obtained were anatomically, geometrically and aerodynamically validated using several techniques (endoscopy, CT scans, acoustic rhinometry and rhinomanometry). RESULTS Our plastination model exhibited a high level of anatomic quality, including a very good mucosa preservation. Aerodynamical and geometrical investigations highlighted a global behaviour of plastinated models perfectly in accordance with a nasal decongested healthy subject. CONCLUSIONS The present plastination model provides a realistic cast of nasal airways, and may be a useful tool for nasal flow, drug delivery and aerosol deposition studies.

Quantification of microsized fluorescent particles phagocytosis to a better knowledge of toxicity mechanisms

Background: The use of micro- or nanometric particles is in full expansion for the development of new technologies. These particles may exhibit variable toxicity levels depending on their physicochemical characteristics. We focused our attention on macrophages (MA), the main target cells of the respiratory system responsible for the phagocytosis of the particles. The quantification of the amount of phagocytosed particles seems to be a major element for a better knowledge of toxicity mechanisms. The aim of this study was to develop a quantitative evaluation of uptake using both flow cytometry (FCM) and confocal microscopy to distinguish entirely engulfed fluorescent microsized particles from those just adherent to the cell membrane and to compare these data to in vitro toxicity assessments. Methods: Fluorescent particles of variable and well-characterised sizes and surface coatings were incubated with MA (RAW 264.7 cell line). Analyses were performed using confocal microscopy and FCM. The biological toxicity of the particles was evaluated [lactate dehydrogenase (LDH) release, tumor necrosis factor (TNF)-α, and reactive oxygen species (ROS) production]. Results and conclusion: Confocal imaging allowed visualization of entirely engulfed beads. The amount of phagocytic cells was greater for carboxylate 2-µm beads (49 ± 11%) than for amine 1-µm beads (18 ± 5%). Similarly, side scatter geometric means, reflecting cellular complexity, were 446 ± 7 and 139 ± 12, respectively. These results confirm that the phagocytosis level highly depends on the size and surface chemical groups of the particles. Only TNF-α and global ROS production varied significantly after 24-h incubation. There was no effect on LDH and H2O2 production.

Impact of acoustic airflow nebulization on intrasinus drug deposition of a human plastinated nasal cast: New insights into the mechanisms involved

PURPOSE The impact of 100 Hz (Hertz) acoustic frequency airflow on sinus drug deposition of aerosols was investigated using a human plastinated nasal cast. The influence of drug concentration and endonasal anatomical features on the sinus deposition enhanced by the 100 Hz acoustic airflow was also examined. METHODS Plastinated models were anatomically, geometrically and aerodynamically validated (endoscopy, CT scans, acoustic rhinometry and rhinomanometry). Using the gentamicin as a marker, 286 experiments of aerosol deposition were performed. Changes of airborne particles metrology produced under different nebulization conditions (100 Hz acoustic airflow and gentamicin concentration) were also examined. RESULTS Aerodynamic and geometric investigations highlighted a global behaviour of plastinated models in perfect accordance with a nasal decongested healthy subject. The results of intrasinus drug deposition clearly demonstrated that the aerosols can penetrate into the maxillary sinuses. The 100 Hz acoustic airflow led to increase the deposition of drug into the maxillary sinuses by a factor 2-3 depending on the nebulization conditions. A differential intrasinus deposition of active substance depending on maxillary ostium anatomical features and drug concentration was emphasized. CONCLUSION The existence of a specific transport mechanism of penetration of nebulized particles delivered with acoustic airflow was proposed.

In vitro cellular responses to silicon carbide nanoparticles: impact of physico-chemical features on pro-inflammatory and pro-oxidative effects

Silicon carbide is an extremely hard, wear resistant, and thermally stable material with particular photoluminescence and interesting biocompatibility properties. For this reason, it is largely employed for industrial applications such as ceramics. More recently, nano-sized SiC particles were expected to enlarge their use in several fields such as composite supports, power electronics, biomaterials, etc. However, their large-scaled development is restricted by the potential toxicity of nanoparticles related to their manipulation and inhalation. This study aimed at synthesizing (by laser pyrolysis or sol–gel methods), characterizing physico-chemical properties of six samples of SiC nanopowders, then determining their in vitro biological impact(s). Using a macrophage cell line, toxicity was assessed in terms of cell membrane damage (LDH release), inflammatory effect (TNF-α production), and oxidative stress (reactive oxygen species generation). None of the six samples showed cytotoxicity while remarkable pro-oxidative reactions and inflammatory response were recorded, whose intensity appears related to the physico-chemical features of nano-sized SiC particles. In vitro data clearly showed an impact of the extent of nanoparticle surface area and the nature of crystalline phases (α-SiC vs. β-SiC) on the TNF-α production, a role of surface iron on free radical release, and of the oxidation state of the surface on cellular H2O2 production.

Detection and analysis of nanoparticles in patients: A critical review of the status quo of clinical nanotoxicology.

On the cusp of massive commercialization of nanotechnology-enhanced products and services, the physical and chemical analysis of nanoparticles in human specimens merits immediate attention from the research community as a prerequisite for a confident clinical interpretation of their occurrence in the human organism. In this review, we describe the caveats in current practices of extracting and isolating nanoparticles from clinical samples and show that they do not help truly define the clinical significance of detected exogenous nano-sized objects. Finally, we suggest a systematic way of tackling these demanding scientific tasks. More specifically, a precise and true qualitative evaluation of nanoparticles in human biological samples is still hindered by various technical reasons. Such a procedure is more refined when the nature of the pollutants is known, like in the case of nano-sized wear debris originating from biomedical prostheses. Nevertheless, nearly all available analytical methods provide unknown quantitative accuracy and qualitative precision due to the challenging physical and chemical nature of nanoparticles. Without trustworthy information to describe the nanoparticulate load of clinical samples, it is impossible to accurately assess its pathological impact on isolated cases or allow for relevant epidemiological surveys on large populations. Therefore, we suggest that the many and various specimens stored in hospitals be used for the refinement of methods of exhaustive quantitative and qualitative characterization of prominent nanoparticles in complex human milieu.

Size of submicrometric and nanometric particles affect cellular uptake and biological activity of macrophages in vitro.

Background: Micrometric and nanometric particles are increasingly used in different fields and may exhibit variable toxicity levels depending on their physicochemical characteristics. The aim of this study was to determine the impact of the size parameter on cellular uptake and biological activity, working with well-characterized fluorescent particles. We focused our attention on macrophages, the main target cells of the respiratory system responsible for the phagocytosis of the particles. Methods: FITC fluorescent silica particles of variable submicronic sizes (850, 500, 250 and 150 nm) but with similar surface coating (COOH) were tailored and physico-chemically characterized. These particles were then incubated with the RAW 264.7 macrophage cell line. After microscopic observations (SEM, TEM, confocal), a quantitative evaluation of the uptake was carried out. Fluorescence detected after a quenching with trypan blue allows us to distinguish and quantify entirely engulfed fluorescent particles from those just adhering to the cell membrane. Finally, these data were compared to the in vitro toxicity assessed in terms of cell damage, inflammation and oxidative stress (evaluated by LDH release, TNF-α and ROS production respectively). Results and conclusion: Particles were well characterized (fluorescence, size distribution, zeta potential, agglomeration and surface groups) and easily visualized after cellular uptake using confocal and electron microscopy. The number of internalized particles was precisely evaluated. Size was found to be an important parameter regarding particles uptake and in vitro toxicity but this latter strongly depends on the particles doses employed.

Aluminum content of human semen: implications for semen quality.

A deterioration of human semen quality has been observed over recent decades. A possible explanation could be an increased exposure to environmental pollutants, including aluminum. Our aim was to measure the aluminum concentration in the semen of 62 patients and to carry out a preliminary evaluation on its impact on specific semen parameters. For each patient, semen analyses were performed according to WHO guidelines. A graphite furnace atomic absorption spectrometry method was used to determine semen aluminum concentration. A cytological analysis using an aluminum-specific fluor, lumogallion, was also performed. The mean aluminum concentration in human semen was 339 μg/L. Patients with oligozoospermia had a statistically higher aluminum concentration than others. No significant difference was observed for other semen parameters. Cytological analysis showed the presence of aluminum in spermatozoa. This study provided unequivocal evidence of high concentrations of aluminum in human semen and suggested possible implications for spermatogenesis and sperm count.