Search

During severe septic shock and/or severe acute respiratory distress syndrome (ARDS) patients present with a limited cardio-ventilatory reserve (low cardiac output and blood pressure, low mixed venous saturation, increased lactate, low PaO2/FiO2 ratio, etc.), especially when elderly patients or co-morbidities are considered. Rescue therapies (low dose steroids, adding vasopressin to noradrenaline, proning, almitrine, NO, extracorporeal membrane oxygenation, etc.) are complex. Fever, above 38.5-39.5°C, increases both the ventilatory (high respiratory drive: large tidal volume, high respiratory rate) and the metabolic (increased O2 consumption) demands, further limiting the cardio-ventilatory reserve. Some data (case reports, uncontrolled trial, small randomized prospective trials) suggest that control of elevated body temperature (“fever control”) leading to normothermia (35.5-37°C) will lower both the ventilatory and metabolic demands: fever control should simplify critical care management when limited cardio-ventilatory reserve is at stake. Usually fever control is generated by a combination of general anesthesia (“analgo-sedation”, light total intravenous anesthesia), antipyretics and cooling. However general anesthesia suppresses spontaneous ventilation, making the management more complex. At variance, alpha-2 agonists (clonidine, dexmedetomidine) administered immediately following tracheal intubation and controlled mandatory ventilation, with prior optimization of volemia and atrio-ventricular conduction, will reduce metabolic demand and facilitate normothermia. Furthermore, after a rigorous control of systemic acidosis, alpha-2 agonists will allow for accelerated emergence without delirium, early spontaneous ventilation, improved cardiac output and micro-circulation, lowered vasopressor requirements and inflammation. Rigorous prospective randomized trials are needed in subsets of patients with a high fever and spiraling toward refractory septic shock and/or presenting with severe ARDS. [ABSTRACT FROM AUTHOR]

This paper aims at reviewing recent work dedicated in this lab to the elaboration and applications in the biomedical domain of hydrophilic stimuli-responsive latex particles based on the use of various polyalkyl(meth)acrylamides together with functional monomers bearing bioreactive groups. At first, a brief description is provided on the synthesis of such particles, differing in their surface and internal morphology, through radical-initiated polymerization processes in heterogeneous media. Then, it is shown that several colloidal properties of these particles drastically change, not only as a function of temperature, but also vs. pH and salinity. Knowledge of these characteristics is a prerequisite for optimal control of the immobilization of various biologically-active macromolecules, mostly by covalent binding. Finally, some applications of these particles are described, especially for improving sensitivity in gene diagnostics or for the separation and concentration of biomolecules. [ABSTRACT FROM AUTHOR]

A very accurate inverse scattering method for reconstructing the contours of perfectly conducting cylinders of arbitrary cross-section illuminated by electromagnetic waves under TM polarization with time-harmonic dependence is presented. No assumption is made on the shapes of the contours nor on their number. Inversion strategy consists in computing a special deformation velocity, defined on the contours of the objects, and allowing to decrease a cost function at each interation. Level set methods, used in as diverse fields as fluid dynamics, image processing and crystal growth, are used to perform the evolution of the contours. These methods allow to handle automatically topological changes by using a Eulerian point of view built on a level set representation of the contours. Hence, several objects can be retrieved from one single initial contour. Moreover, contours regularization is easily performed by adding a curvature term to the velocity. The inverse scattering method is based on a very accurate forward scattering algorithm characterized by the use of well-behaved pseudo-currents which are developed in Fourier series along the contours. The frequency hopping technique turns out to play a key role in the inversion process. The method is proved to be flexible, allowing to reconstruct accurately complex and multiple shape contours from one single initial guess. The deformation velocity is even able to retrieve very sharp corners and is quite robust with respect to high noise levels. [ABSTRACT FROM AUTHOR]

The activation of various synthetic oligodeoxyribonucleotides (ODNs), bearing a hexamethylamine arm at their 5′-end, with the 2,4-phenylenediisothiocyanate (PDC) was studied. The activation reaction had to be performed within 40 min, because of competitive hydrolysis of the isothiocyanate functions. ODN modifications were then characterized by different analytical methods i.e. gel capillary electrophoresis, Matrix-Assisted Laser Desorption-Ionization-Time of Flight (MALDI-TOF) mass spectrometry. Moreover, activation of the amine groups of the nucleic bases was evidenced through the chemical analysis of the enzymatic-digested conjugate (PDC-ODN) by reverse phase HPLC. Preliminary results on the covalent grafting of activated ODN molecules onto the aminated latex particles showed that the amount of grafted ODNs was directly related to the number of potential grafting sites on the nucleic acid probe (primary amine group of hexamethyl arm and amine functions of the nucleic bases). [ABSTRACT FROM AUTHOR]

(Polymer-oligonucleotide) conjugates were obtained via direct ON synthesis from the poly(ethylene-alt-maleic anhydride: PEMA) grafted onto glass bead surfaces. The effect of the ON number per polymer chain on binding was evaluated through Tm experiments. Results were correlated with ELOSA (Enzyme Linked Oligosorbent Assay) tests run with conjugates in the capture step. [ABSTRACT FROM AUTHOR]