Diagnostic accuracy of procalcitonin in critically ill immunocompromised patients

<p>Abstract</p> <p>Background</p> <p>Recognizing infection is crucial in immunocompromised patients with organ dysfunction. Our objective was to assess the diagnostic accuracy of procalcitonin (PCT) in critically ill immunocompromised patients.</p> <p>Methods</p> <p>This prospective, observational study included patients with suspected sepsis. Patients were classified into one of three diagnostic groups: no infection, bacterial sepsis, and nonbacterial sepsis.</p> <p>Results</p> <p>We included 119 patients with a median age of 54 years (interquartile range [IQR], 42-68 years). The general severity (SAPSII) and organ dysfunction (LOD) scores on day 1 were 45 (35-62.7) and 4 (2-6), respectively, and overall hospital mortality was 32.8%. Causes of immunodepression were hematological disorders (64 patients, 53.8%), HIV infection (31 patients, 26%), and solid cancers (26 patients, 21.8%). Bacterial sepsis was diagnosed in 58 patients and nonbacterial infections in nine patients (7.6%); 52 patients (43.7%) had no infection. PCT concentrations on the first ICU day were higher in the group with bacterial sepsis (4.42 [1.60-22.14] vs. 0.26 [0.09-1.26] ng/ml in patients without bacterial infection, <it>P </it>< 0.0001). PCT concentrations on day 1 that were > 0.5 ng/ml had 100% sensitivity but only 63% specificity for diagnosing bacterial sepsis. The area under the receiver operating characteristic (ROC) curve was 0.851 (0.78-0.92). In multivariate analyses, PCT concentrations > 0.5 ng/ml on day 1 independently predicted bacterial sepsis (odds ratio, 8.6; 95% confidence interval, 2.53-29.3; <it>P </it>= 0.0006). PCT concentrations were not significantly correlated with hospital mortality.</p> <p>Conclusion</p> <p>Despite limited specificity in critically ill immunocompromised patients, PCT concentrations may help to rule out bacterial infection.</p

The role of renal hypoperfusion in development of renal microcirculatory dysfunction in endotoxemic rats

To study the role of renal hypoperfusion in development of renal microcirculatory dysfunction in endotoxemic rats. Rats were randomized into four groups: a sham group (n = 6), a lipopolysaccharide (LPS) group (n = 6), a group in which LPS administration was followed by immediate fluid resuscitation which prevented the drop of renal blood flow (EARLY group) (n = 6), and a group in which LPS administration was followed by delayed (i.e., a 2-h delay) fluid resuscitation (LATE group) (n = 6). Renal blood flow was measured using a transit-time ultrasound flow probe. Microvascular perfusion and oxygenation distributions in the renal cortex were assessed using laser speckle imaging and phosphorimetry, respectively. Interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α were measured as markers of systemic inflammation. Furthermore, renal tissue samples were stained for leukocyte infiltration and inducible nitric oxide synthase (iNOS) expression in the kidney. LPS infusion worsened both microvascular perfusion and oxygenation distributions. Fluid resuscitation improved perfusion histograms but not oxygenation histograms. Improvement of microvascular perfusion was more pronounced in the EARLY group compared with the LATE group. Serum cytokine levels decreased in the resuscitated groups, with no difference between the EARLY and LATE groups. However, iNOS expression and leukocyte infiltration in glomeruli were lower in the EARLY group compared with the LATE group. In our model, prevention of endotoxemia-induced systemic hypotension by immediate fluid resuscitation (EARLY group) did not prevent systemic inflammatory activation (IL-6, IL-10, TNF-α) but did reduce renal inflammation (iNOS expression and glomerular leukocyte infiltration). However, it could not prevent reduced renal microvascular oxygenatio

Micro Raman spectroscopy and Raman imaging for the study of (photo)reactivity and heterogeneity of single levitated droplets

International audienceIn atmospheric chemistry, each aerosol particle acts as a small mobile reactor where several heterogeneous chemical reactions lead to the modification of its size, chemical composition and structure; as well as the consumption and release of chemical agents from its gaseous environment. Despite its relevance, information on the chemical and photochemical processes that occur in atmospheric aerosols is still scarce, mainly due to the instrumental difficulties involved in studying such processes on a surface scale. In this regard, Micro-Raman spectroscopy coupled to a levitation technique, through an environmental levitation cell, is especially useful for studying - at micrometric scale - the in-situ modifications of aerosol when exposed to reactive or damp environments without the influence of a contacting surface (Krieger, et al. 2012). This work deals with two main objectives. On one hand, the monitoring of physical- and photo-chemical processes occurring in levitated single particles; and in the other hand, the coupling and instrumental developments carried out to perform Raman imaging studies of single levitated particles. We will show the coupling between the confocal Raman microscope and the adapted photochemical environmental levitation cell, as well as the heterogeneous distribution of (photo)chemical products on levitated particles (less than 10 µm of size) evidenced by reconstruction of the Raman spectral image.This work was supported by funds from the “Laboratoire d’Excellence” (LABEX) -CaPPA- (ANR-11-LABX-0005-01) and CPER research project CLIMIBIO.Andreae, M. O., and Crutzen, P. J. (1997). Science 276, 1052-1058. Krieger, U. K., Marcolli, C., and Reid, J. P. (2012). Chem. Soc. Rev. 41, 6631-6662

Hydrothermal preparation of MoS₂/TiO₂/Si nanowires composite with enhanced photocatalytic performance under visible light

International audienceIn this paper, we report on a simple, low cost and environmentally friendly method for the synthesis of 3D hierarchical molybdenum disulfide (MoS2) nano-sheets on TiO2 coated Si nanowires (SiNW). The synthetic method has several advantages such as low temperature, short reaction time and does not require any additives or surfactants. Characterization of the obtained composite material was performed by using scanning electron microscopy (SEM), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) patterns and high resolution transmission electron microscopy (HR-TEM). The photocatalytic activity of the as-prepared MoS2 nanosheets was investigated for the degradation of Rhodamine B (RhB) under visible light irradiation. We found that MoS2/TiO2/SiNW interface exhibited stable and good catalytic activity as compared to other MoS2-based photocatalytic materials. The photocatalytic mechanism is believed to occur through photocatalytic and photosensitization processes

CO2 laser–induced precipitation of semiconductor nanoparticles in a dense glass

International audienceNanostructures based on II-VI semiconductor nanocrystallites (NCs) embedded in glass have been studied for many years. Among these systems, the pseudo-binary CdSxSe1-x nanostructures are of particular interest, owing to their optical absorption and emission spectra that cover the entire visible spectral region. Laser irradiation methods have been shown to allow the local growth of several types of NCs in various kinds of matrices. Unfortunately, in the case of the CdSxSe1-x doped silicate glasses, a near-infrared fs laser irradiation, instead of nucleating NCs, leads to permanent refractive index changes in micro-size regions within the glass and may even provoke glass damages at the highest pulse energies. A novel method allowing the local growth of semiconductor nanoparticles in dense silicate glasses is presented. In this method, combining a continuous middle-infrared laser irradiation and a heat-treatment in open air, a transparent melt-quenched borosilicate glass containing CdSxSe1-x nanocrystals was annealed at a temperature below the softening point. Simultaneously, a continuous infrared laser irradiation at 10.6 µm was applied, acting as a thermal addition. Spectroscopic studies reveal the local growth of CdSxSe1-x nanoparticles, with a homogeneous composition and average particle radii ranging from 1.9 to 5.5 nm. These results demonstrate the feasibility of coupling a laser irradiation with an appropriate heat-treatment in order to achieve the spatial organization

Synthesis and photocatalytic activity of iodine-doped ZnO nanoflowers

The paper reports on the preparation and photocatalytic activity of thin films of iodine-doped ZnO nanoflowers deposited on glass substrate using a simple growth process based on hydrothermal synthesis. Addition of iodic acid (5-20 vol%) in the reaction mixture allows the introduction of iodine ions in the form of I− or IO3− in the ZnO lattice, as suggested by X-ray photoelectron spectroscopy. Doping ZnO nanostructured films with iodine did not impact their morphology, while it has a significant influence on their optical properties. Indeed, the nanostructured ZnO films, prepared in the presence of iodic acid, display a large increase of the visible luminescence, which reaches a maximum at a concentration of 10 vol%. Finally, the photocatalytic activity of the ZnO nanostructured films for the photodegradation of a model pollutant, rhodamine B, was evaluated under UV and visible light irradiation. While under UV light irradiation, both undoped and iodine-doped ZnO films show a similar behavior, the photocatalytic performance of iodine-doped under visible light irradiation is significantly enhanced in comparison to that of undoped ZnO