Reconstruction microchirurgicale et prise en charge globale des patients porteurs de cancer ORL : l’importance d’une approche qualité et d’un circuit protocolisé [Microsurgical reconstruction and full management of patients with head and neck cancer: Importance of a quality approach and a circuit protocolisation]

Main of study: Management and surgical reconstruction of head and neck cancers remain a challenge. From the first consultation to surgery and radiotherapy, it is necessary to save time to ensure optimum treatment and better survival rates. Objectif: To establish a kind of quality approach to the management of patients with head and neck cancers. 54 patients who had microsurgical reconstruction after head and neck cancer were included in this study between 1997 and 2006. Results : Multiple data were considered: body mass index (BMI), ASA stage, age, existence of a pre-or postoperative radiotherapy, the surgeon's experience and the number of veins drainage. The success rate is superior when more than one draining vein is sutured to the flap for patients with a BMI > 20. Radiotherapy does not seem to affect the survival of the flap. Conclusion: According to current literature, the survival rate of these patients is better when the overall time care is less than 100 days. That period is possible with a perfect organization of the medical and paramedical team. Therefore, we propose to include these patients in a circuit protocolisation care, which saves time, to better inform patients and improve survival rates. Buts: la prise en charge et la reconstruction chirurgicale des cancers ORL restent un challenge. De la première consultation à la chirurgie et la radiothérapie, il est nécessaire de gagner du temps afin d’assurer une traitement optimum et un meilleur taux de survie. Objectif : établir une sorte d’approche qualité de la prise en charge des patients porteurs de cancers ORL. 54 patients qui ont bénéficié d’une reconstruction microchirurgicale suite à un cancer ORL ont été inclus dans cette étude entre 1997 et 2006. Résultats : plusieurs données ont été étudiées : l’index de masse corporelle (IMC), le stade ASA, l’âge, l’existence d’une radiothérapie pré ou post opératoire, l’expérience du chirurgien ainsi que le nombre de veines de drainage. Le taux de succès se révèle supérieur lorsque plus d’une veine de drainage est suturée au lambeau, pour des patients ayant un IMC > 20. La radiothérapie ne semble pas avoir de répercussion sur la survie du lambeau. Conclusion : conformément à la littérature actuelle, le taux de survie de ces patients est meilleur lorsque le temps global de prise en charge est inférieur à 100 jours. Ce délai court n’est possible qu’avec une parfaite organisation de l’équipe médicale et paramédicale. De ce fait, nous proposons d’inclure ces patients dans un circuit de prise en charge protocolisé, ce qui permet de gagner du temps, de mieux informer le patient et d’améliorer le taux de survie

Anxiety modulates cognitive deficits in a perinatal glutathione deficit animal model of schizophrenia.

In this study, we investigated long-term repercussion of early glutathione deficit by l-buthionine-(S,R)-sulfoximine (BSO) injections as a rat model of schizophrenia. BSO rats were tested through various behavioral tasks requiring animals to take into account previously delivered information. We showed that relative to controls, BSO rats (1) were less active and more anxious in an Elevated Plus Maze test, allowing us to split them into two subgroups with high and low anxiety levels; (2) demonstrated normal abilities of behavioral flexibility tested with a rat-adapted version of the Wisconsin Card Sorting Test (WCST), with even higher abilities in anxious BSO rats suggesting reduced interference of previously acquired rules; (3) did not forage normally in radial arm mazes and mainly used clockwise strategies; (4) exhibited a lack of habituation during a startle response task; and (5) showed a normal prepulse inhibition of the startle response (PPI) and a normal conditioned taste aversion (CTA). All these results indicate that early glutathione deficit provokes persistent changes in adulthood and improves the validity of this animal model of schizophrenia. They further suggest difficulties binding temporally separated events (WCST), except when the salience of this information is very strong (CTA). We propose that the transient glutathione deficit during cerebral development could alter a "cognitive binding" process in interaction with the emotional state that could possibly account for the disruption of integrative function that characterizes schizophrenia

PIXSIC, a wireless radiosensitive intracerebral probe to monitor PET radiotracers in anaesthetized and awake rat

Présentation oraleAim. In neuroscience, PET functional imaging and behavioural assays in rodents are complementary approaches, despite the fact that they are rarely associated simultaneously because general anaesthesia inherent to PET precludes behavioural studies. To address this methodological limit, we have developed a radiosensitive pixelated intracerebral probe, PIXSIC, that provides access to the combination of simultaneous observations of molecular and behavioural parameters on rodents. Material and Methods. PIXSIC proposes a novel strategy for in vivo recording of the local time-activity curves of PET radiopharmaceuticals. It relies on a sub-millimetre pixelated probe of Si (17 mm long hosting 10 pixels with dimension 200 µm x 500 µm) implanted into the brain region of interest by stereotaxic surgery. Positrons are detected by reverse-biased, high-resistivity silicon diodes. The system Aims at time-resolved high sensitivity measurements in a volume of a few mm3. The pixelated detection scheme adds "imaging" features as it allows recording of the time-activity curves in different brain regions along the probe position. PIXSIC has a compact and autonomous design based on a radiofrequency data exchange link that allows for full freedom in the animals motion and behavioural activity while limiting stress during acquisition. Results and Conclusion. The first biological validations were performed on anaesthetized rats implanted with two probes, one in the region of interest (hippocampus or striatum, according to the radiotracer) and the other one in a control region (cerebellum). We used [11C]-raclopride for dopamine D2 receptors and [18F]-MPPF for serotonin 5HT1A receptors. According to our previous studies with the Beta-Microprobe (J Nucl Med 2002, 43(2):227-33; Eur J Nucl Med 2002 29(9) 1237-47), the radioactive signals measured with the PIXSIC pixels are reproducible and well-correlated with the distributions of the targeted receptors. The simultaneous measurement of implanted rats in a small animal PET camera confirmed the similarity between PIXSIC and microPET time-activity curves. Moreover, the binding curves highlighted the possibility for PIXSIC to distinguish different tracer kinetics within the structure of interest (cortex/striatum or cortex/hippocampus) in accordance to the stereotaxic location of the pixels. In addition, PIXSIC allowed us to perform the first kinetic measurements of [11C]-raclopride and [18F]-MPPF on awake and freely moving rats. In conclusion, PIXSIC constitutes an unprecedented instrumental methodology for connecting PET molecular imaging and behavioral measurements with freely-moving rodents

Combined effect of carbon dioxide and sulfur on vapor-liquid partitioning of metals in hydrothermal systems

Although CO2 is a ubiquitous volatile in geological fluids typically ranging from a few to more than 50 wt%, its effect on metal vapor-liquid fractionation during fluid boiling and immiscibility phenomena in the Earth's crust remains virtually unknown. Here we conducted first experiments to quantify the influence of CO2 on the partition of different metals in model water + salt + sulfur + CO2 systems at 350 degrees C and CO2 pressures up to 100 bar, which are typical conditions of formation of many hydrothermal ore deposits. In addition, we performed in situ Raman spectroscopy measurements on these two-phase systems, to determine sulfur and carbon speciation in the liquid and vapor phases. Results show that, in S-free systems and across a CO2 concentration range of 0-50 wt% in the vapor phase, the absolute vapor-liquid partitioning coefficients of metals (K-vap/liq = C-vap/C-liq, where C is the mass concentration of the metal in the corresponding vapor and liquid phase) are in the range 10(-6)-10(-5) for Mo; 10(-4)-10(-3) for Na, K, Cu, Fe, Zn, Au; 10(-3)-10(-2) for Si; and 10(-4)-10(-1) for Pt. With increasing CO2 from 0 to 50 wt%, K-vap/liq values decrease for Fe, Cu and Si by less than one order of magnitude, remain constant within errors (+/- 0.2 log unit) for Na, K and Zn, and increase by 0.5 and 2 orders of magnitude, respectively for Au and Pt. The negative effect of CO2 on the partitioning of some metals is due to weakening of hydration of chloride complexes of some metals (Cu, Fe) in the vapor phase and/or salting-in effects in the liquid phase (Si), whereas both phenomena are negligible for complexes of other metals (Na, K, Zn, Mo). The only exception is Pt (and in a lesser extent Au), which partitions significantly more to the vapor of S-free systems in the presence of CO2, likely due to formation of volatile carbonyl (CO) complexes. In the S-bearing system, with H2S content of 0.1-1.0 wt% in the vapor, K-vap/liq values of Cu, Fe, Mo, and Au are in the range 0.01-0.1, those of Pt 0.5-2.0, those of alkali metals are similar to the S-free system, and the partitioning of none of the studied metals is influenced by the presence of CO2 (up to 50 wt% in the vapor). Our data thus confirm the large enhancement of volatility in the presence of reduced sulfur (H2S) due to formation of sulfide complexes for chalcophile metals such as Au, Pt, Mo and, to a lesser extent, Cu and Fe, as reported in previous studies of CO2-free water-salt systems. The negligible effect of CO2 on vapor-liquid partitioning of the studied metals in S-bearing systems is due to the lack of hydration of metal sulfide species making them little sensitive to changes in water activity and solvation power of CO2-H2O vapor. Our findings, combined with existing data over a wide range of temperature on vapor-liquid partitioning of metals in H2O-dominated systems, suggest that CO2 exerts mostly an indirect impact on metal fractionation, by extending vapor-liquid immiscibility to higher temperatures and pressures or depth compared to a CO2-free H2O-S-salt system. The deeper vapor-liquid separation, in particular in S-bearing systems, is expected to cause more significant partitioning of precious metals and molybdenum (Au, Pt, Mo) into the vapor phase while base metals (Fe, Zn, Cu) remain concentrated in the salt-rich (NaCl, KCl) liquid phase. In addition, irrespective of the presence of sulfur, an expansion of the immiscibility domain to higher temperature and pressure conditions in the presence of CO2 will also increase the depth of ore deposition and affect the vertical metal zonation in hydrothermal systems

MAPSSIC, a communicating MAPS-based intracerebral positrons probe for deep brain imaging in awake and freely-moving rats

Radioisotope imaging is a powerful tool to understand the biological mechanisms in-vivo, especially in the brain of small animals, providing a significant model to study the human brain. In this context, we have developed and built a pixelated intracerebral positron probe to be embedded on awake and freely moving small animals, typically rats. This pixelated probe will represent a key instrument for neuroscientists to study neural mechanisms and correlate them to behavioral experiments. We describe in this paper the simulations carried out to design the intracerebral sensor, its architecture, and the detection of positrons in a volume with a couple of sensors assembled back-to-back. We also depict the architecture of the wireless acquisition system. Finally, we present the first measurements performed in real-time by this miniaturized probe with sealed radioactive sources and a 18F solution

MAPSSIC, a communicating MAPS-based intracerebral positrons probe for deep brain imaging in awake and freely-moving rats

International audienceRadioisotope imaging is a powerful tool to understand the biological mechanisms in-vivo, especially in the brain of small animals, providing a significant model to study the human brain.In this context, we have developed and built a pixelated intracerebral positron probe to be embedded on awake and freely moving small animals, typically rats. This pixelated probe will represent a key instrument for neuroscientists to study neural mechanisms and correlate them to behavioral experiments.We describe in this paper the simulations carried out to design the intracerebral sensor, its architecture, and the detection of positrons in a volume with a couple of sensors assembled back-to-back. We also depict the architecture of the wireless acquisition system. Finally, we present the first measurements performed in real-time by this miniaturized probe with sealed radioactive sources and a 18F solution.Key words: Active pixel sensors / Animal behavior / CMOS Image sensors / Implants / Molecular imaging / Monte Carlo methods / Nuclear Imaging / Positron emission tomograph