Monitoring of circulating monocyte HLA-DR expression in a large cohort of intensive care patients: relation with secondary infections.

INTRODUCTION: The reports of an early and profound acquired immunodepression syndrome (AIDs) in ICU patients had gained sufficient credence to modify the paradigm of acute inflammation. However, despite several articles published on AIDs and its assessment by monocytic HLA-DR monitoring, several missing informations remained: 1-Which patients' are more prone to benefit from mHLA-DR measurement, 2-Is the nadir or the duration of the low mHLA-DR expression the main parameter to consider? 3-What are the compared performances of leukocytes' count analyses (lymphocyte, monocyte). MATERIAL AND METHOD: We conducted an observational study in a surgical ICU of a French tertiary hospital. A first mHLA-DR measurement (fixed flow cytometry protocol) was performed within the first 3 days following admission and a 2nd, between day 5 and 10. The other collected parameters were: SAPS II and SOFA scores, sex, age, comorbidities, mortality and ICU-acquired infections (IAI). The associations between mHLA-DR and outcomes were tested by adjusted Fine and Gray subdistribution competing risk models. RESULTS: 1053 patients were included in the study, of whom 592 had a 2nd mHLA-DR measurement. In this cohort, 223 patients (37.7%) complicated by IAI. The initial decrement in mHLA-DR was not associated with the later occurrence of IAI, (p = 0.721), however, the persistence of a low mHLA-DR (< 8000 AB/C), measured between day 5 and day 7, was associated with the later occurrence of IAI (p = 0.01). Similarly, a negative slope between the first and the second value was significantly associated with subsequent IAI (p = 0.009). The best performance of selected markers was obtained with the combination of the second mHLA-DR measurement with SAPSII on admission. Persisting lymphopenia and monocytopenia were not associated with later occurrence of IAI. CONCLUSION: Downregulation of mHLA-DR following admission is observed in a vast number of patients whatever the initial motif for admission. IAI mostly occurs among patients with a high severity score on admission suggesting that immune monitoring should be reserved to the most severe patients. The initial downregulation did not preclude the later development of IAI. A decreasing or a persisting low mHLA-DR expression below 8000AB/C within the first 7 days of ICU admission was independently and reliably associated with subsequent IAI among ICU patients with performances superior to leukocyte subsets count alone.

Comparative structural and vibrational investigations between cocoa butter (CB) and cocoa butter equivalent (CBE) by ESI/MALDI-HRMS, XRD, DSC, MIR and Raman spectroscopy.

A high quality chocolate requires not only a shiny surface, a crunchy and pleasant texture, but also a proper resistance to blooming. All these characteristics are influenced by the physical and chemical properties of the components, which are directly related to their crystalline structure. Some works found that the proportion of cocoa butter (CB), cocoa butter equivalent (CBE) and milk fatty acid (AMF) tend to strongly delay the blooming when mixing them. The goal of our research is to determine how the choice of adding CBE to the mixture delays chocolate blooming. ESI/MALDI-HRMS, X-ray, DSC, MIR and Raman investigations were used to analyze the structure features and the vibrational modes of CB and CBE. The comparison of these experimental results between CB and CBE made it possible to highlight markers of differentiation between CB and CBE which seems to explain the impact of CBE in the chocolate blooming. Part of these triglycerides remains in form IV instead. The presence of the latter seems to be a key parameter that favors the transformation deceleration to the form VI, which is responsible for the fat bloom development.

Lipid-based Janus nanoparticles for pharmaceutical and cosmetic applications: Kinetics and mechanisms of destabilization with time and temperature.

The aim of this paper is to investigate the time and thermal stability of innovative multicompartmental nanoparticles. These particles, having a hydrophilic side and a hydrophobic side, belong to the family of Janus particles and are promising tools to carry active ingredients with opposite solubilities in a unique nanocarrier. The stability of nanoparticles obtained with mainly two types of polyoxylglycerides (Labrafil® M2125 CS and Labrafil® M1944 CS) has been investigated. The suspensions describe a two-step maturation/destabilization process with an Ostwald ripening phase followed by the coalescence of the particles. The effect of lipid composition and temperature on these steps has been investigated in deep as stability with temperature is a critical parameter to consider in order to envisage the development of any formulation for pharmaceutical or cosmetic uses. These nanoparticles were particularly stable at room temperature as their hydrodynamic diameter did not change significantly for 20 months. Contrarily, a strong dependency to temperature appears when storage temperature increases from 25 °C to 43 °C. Indeed, Labrafil® M1944 CS seemed to undergo a progressive destabilization where a significant increase of particles size is visible from 25 °C and phase separation occurred after 4 months at 32 °C. At the opposite, Labrafil® M2125 CS remained stable until 36 °C and reached a threshold temperature between 32 °C and 36 °C after which Labrafil® M2125 CS underwent a consequent increase of particles size at the longer time, i.e. after 6 months. Moreover, Labrafil® M2125 CS formulation was stable at least 3 months at 43 °C.

Critical steps during the prilling process of molten lipids: Main stumbling blocks due to pharmaceutical excipient properties.

Prilling by ultrasonic jet break-up is an efficient process to produce perfectly spherical microparticles homogeneous in size. However, the material properties could affect the manufacturability and the final product properties especially with lipid-based excipients which often exhibit complex structural properties. This work presents the characterisation of six lipid-based excipients differing by their melting point and polymorphic behaviour which were used to produce microspheres using a pilot-scale prilling equipment. The experimental results were compared to theoretical calculations, especially the droplet solidification time which is a key-parameter for this process. This work highlighted that monotropic polymorphism of excipients and supercooling effect have a significant impact on process parameters which should be considered with care during formulation design.

Temperature dependent Raman and X-ray diffraction studies of anhydrous milk fat.

Raman spectroscopy was used to characterize the polymorphs and liquid state of anhydrous milk fat, with emphasis placed on the thermal evolution of the ester carbonyl stretching modes (1800-1700cm-1) and the comparative study of the Raman-active CC (1660cm-1) and CH (3000-2700cm-1) vibrational modes. Specific Raman signatures in the crystalline phase were found and attributed to the coexistence of two groups of triglycerides. This was confirmed using differential scanning calorimetry and X-ray diffraction methods. In the ester carbonyl band, the effect of changing temperature on both the number of modes and new defined intensity ratios was studied and enabled polymorph discrimination. CH stretching signals increased with polymorph stability, indicating the dominance of antisymmetric CH methylene vibrations as the anhydrous milk fats crystal lattice became more ordered. The change in intensity of the CH stretching bands as a function of temperature was used to probe the order-disorder transition.

Superparamagnetic lipid-based hybrid nanosystems for drug delivery.

INTRODUCTION: The development of multifunctional drug carriers provides many opportunities in the field of drug delivery. Among them, carriers loaded with both drug and superparamagnetic iron oxide nanoparticles would allow the combination of chemotherapy with the possibility of monitoring or controlling the distribution of the nanocarrier in the body, triggering drug release and/or applying a synergistic hyperthermia treatment. AREAS COVERED: The present review covers biocompatible lipid-based nanotechnologies that have been employed to co-encapsulate drug and iron oxide. Depending on their physico-chemical properties, lipids are able to generate monophasic lipophilic nanodispersions or more complex structures containing both lipidic and aqueous domains. This review describes the rationale behind these nanoobjects and how they can be prepared. EXPERT OPINION: This review focuses on the co-encapsulation aspects of these hybrid systems and discusses in particular the possible heterogeneities in drug-to-iron oxide ratio and the difficulties that could be encountered in the construction of these biocompatible multifunctional drug carriers.

Lyotropic behavior of Gelucire 50/13 by XRD, Raman and IR spectroscopies according to hydration.

The present paper discuss the structural and vibrational properties of polyoxyethylene glycol glycerides (Gelucire 50/13) during the hydration with increasing water from 0% to 80%. The Gelucire 50/13 used as sustained release matrix forming agent in pharmaceutical applications and it was essentially studied by Small and Wide Angle X-ray Scattering (SWAXS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy according to the rate of hydration. The hydration behavior of this amphiphilic excipient has been investigated in the spectral range 4000-0cm-1 in Raman spectroscopy, and 4000-600cm-1 in FTIR. At increasing water contents Gelucire 50/13 forms successive bicontinuous to micellar supramolecular structures, and the vibrational changes were directly correlated with this conformational changes of the Gelucire structure. Overall, Raman and IR spectroscopy clearly demonstrated that the different functional groups studied could be characterized independently, allowing for the understanding of their role in Gelucire polymorphism.

[Diagnosis of essential thrombocythemia after myocardial infarction and cardiac arrest: A case report]. / Diagnostic d'une thrombocytémie essentielle après infarctus du myocarde compliqué d'arrêt cardio-circulatoire : un cas clinique.

Acute coronary syndrome is now a well-known disease, with codified treatments. The main presentation is chest pain, but more and more cases are revealed by cardiorespiratory arrest thanks to pre-hospital care. And, depending on the evolution in such situations, cardiocirculatory support techniques like extracorporeal membrane oxygenation (ECMO) can be implemented. If the more common cause of SCA is atherosclerosis, consequence of the combination of one or more cardiovascular risk factors, there are rare aetiologies, which include myeloproliferative syndromes, in particular essential thrombocythemia. We describe the case of a 34-year-old man presenting with anterior ST-elevation myocardial infarction complicated by an initial cardiac arrest, whose aetiology is unknown essential thrombocythemia, and its therapeutic management requiring circulatory support by ECMO and IMPELLA(®) techniques.

Critical parameters involved in producing microspheres by prilling of molten lipids: from theoretical prediction of particle size to practice.

The aim of this work was to identify the key parameters which influence the running of the prilling process with lipid material from the initial melting to the formation of solid microspheres. The microsphere size would essentially result from break-up at the Rayleigh-Weber's wavelength which mostly depends on the liquid properties (mass density, surface tension and dynamic viscosity). After molten liquid extrusion through the nozzle, the cooling rate is very fast and the instantaneous temperature of the liquid jet decreases rapidly of 0.2-0.3 °C during the duration of the droplet formation (1-2 ms). This leads to no significant modification of the physical characteristics of the lipids and only a very slight change in the dynamic viscosity. Consequently, no significant effect on the optimal wavelength λ(W) and on droplet formation can occur. However, coalescence of liquid droplets has been observed during their fall, probably caused by turbulence into the air column, leading to a minor population of larger microspheres.

Is monocyte HLA-DR expression monitoring a useful tool to predict the risk of secondary infection?

Downregulation of the immune response is common among Intensive Care Unit (ICU) patients after an acute inflammatory injury, whether it was septic or not. Such a modification could be seen as an adaptation to attenuate the effects of the inflammatory storm on tissues, but it exposes the subject to the risk of nosocomial infection and impairs recovery processes. The intensity of immunity downregulation is difficult to characterize, since clinical presentation is silent and non-specific, which urges the use of tools for immune monitoring. This review focuses on the use of monocyte HLA-DR expression to detect immune hyporesponsiveness and to select the appropriate immunomodulating therapy, as well as the efficiency of this technique in controlling secondary infections.

Anti-inflammatory profile of circulating immune cells after surgery for seizure.

AIM: The central nervous system has been described as the coordinator of the inflammatory response to infection through the hypothalamo-pituitary axis and the autonomic nervous system. Brain lesions have been associated with impaired immunity and postoperative infections. We studied alterations of the inflammatory response in relation to neurohormonal patterns after neurosurgery for seizure. METHODS: Nine patients were studied before, during and immediately after operation, and then on days 1, 2 and 4 post-operatively. Monocyte HLA-DR (mHLA-DR) expression and plasma interleukin (IL)-10, IL-12 and MIF were measured ex vivo and after an in vitro 6-h our lipopolysaccharide (LPS) stimulation of whole blood. Corticotropin (ACTH), cortisol, arginine vasopressin, prolactin, epinephrine and norepinephrine were quantified in plasma. The effect of plasma mediators on LPS stimulation was studied by replacing plasma with standard culture medium. RESULTS: Surgery resulted in decreased ex vivo mHLA-DR expression, but no change in IL-10 or IL-12 plasma levels. mHLA-DR was low in LPS culture over the 4 postoperative days, whereas IL-10 release was increased and not counterbalanced by IL-12p40 production. The hormonal plasma pattern showed increased prolactin during anesthesia and peaks of cortisol, ACTH and arginine vasopressin during waking, but no alteration in catecholamine levels. mHLA-DR expression in LPS culture was not modified by plasma replacement, except immediately after surgery. CONCLUSION: Postoperatively, mHLA-DR expression was associated with an anti-inflammatory phenotype of whole blood. The anti-inflammatory profile was not related to the plasma mediators measured, suggesting that neural control might take place upstream in the circulation, at the level of progenitors in bone marrow.

Expression of monocyte human leukocyte antigen-DR in relation with sepsis severity and plasma mediators.

AIM: After an initial septic hit, the immune response to a new antigen changes as time progresses, with an unpredictable efficiency. The aim of this study was to characterize the monocyte functional phenotype by HLA-DR expression in septic patients at the onset of sepsis and during recovery in relation to organ failure and plasma mediators. METHODS: Twenty-six patients were analyzed as either single organ failure at worst (SOF) or multiple organ failure (MOF) over 14 days. Twelve patients received immunosuppressive (IS) drugs before sepsis. We measured: 1) monocyte HLA-DR expression (mHLA-DR); 2) plasma pro-inflammatory mediators (IL-12p40, macrophage Migration Inhibitory Factor [MIF]); 3) plasma anti-inflammatory mediators (IL-10, cortisol); and 4) in vitro lipopolysaccharide (LPS) stimulated mHLA-DR in 6-hour whole blood culture or after plasma replacement with standard milieu. RESULTS: mHLA-DR expression was equally decreased in patients who were treated with IS drugs as those who were not. Despite the difference in severity, SOF patients showed a similar profound mHLA-DR downregulation as MOF patients at day 0, but tended to recover earlier. MOF patients presented higher plasma IL-10 and cortisol levels than SOF patients but similar plasma IL-12p40 and MIF levels. In vitro LPS stimulation showed an impaired mHLA-DR response in both groups. Plasma replacement by milieu elicited a slight improvement in the response to LPS in SOF but not MOF patients. CONCLUSIONS: At the onset of sepsis, an initial low mHLA-DR was not related to any prior IS drug regimen, the severity of the sepsis or the outcome. The duration of mHLA-DR downregulation could be related to plasma factors in SOF, while other mechanisms may be implicated in MOF evolution.

Accelerated in vitro differentiation of blood monocytes into dendritic cells in human sepsis.

Summary Sepsis-induced immune depression is characterized by infection susceptibility and monocyte early deactivation. Because monocytes are precursors for dendritic cells (DC), alterations in their differentiation into DC may contribute to defective immune responses in septic patients. We therefore investigated the ability of monocytes to differentiate into functional DC in vitro in patients undergoing surgery for peritonitis. Monocytes from 20 patients collected immediately after surgery (D0), at week 1 and at weeks 3-4 and from 11 control donors were differentiated into immature DC. We determined the phenotype of monocytes and derived DC, and analysed the ability of DC to respond to microbial products and to elicit T cell responses in a mixed leucocyte reaction (MLR). We show that, although monocytes from septic patients were deactivated with decreased responses to lipopolysaccharide (LPS) and peptidoglycan and low human leucocyte antigen D-related (HLA-DR) expression, they expressed the co-stimulatory molecule CD80, CD40 and CCR7. Monocytes collected from patients at D0 and week 1 differentiated faster into DC with early loss of CD14 expression. Expression of HLA-DR increased dramatically in culture to reach control levels, as did responses of DC to LPS and peptidoglycan. However, although patient and control immature DC had similar abilities to induce T cell proliferation in MLR, maturation of DC derived from patients did not increase T cell responses. These results show that circulating monocytes from septic patients express markers of activation and/or differentiation despite functional deactivation, and differentiate rapidly into phenotypically normal DC. These DC fail, however, to increase their T cell activation abilities upon maturation.

Gastroretentive dosage forms: overview and special case of Helicobacter pylori.

The challenge to develop efficient gastroretentive dosage forms began about 20 years ago, following the discovery of Helicobacter pylori by Warren and Marshall. In order to understand the real difficulty of increasing the gastric residence time of a dosage form, we have first summarized the important physiologic parameters, which act upon the gastric residence time. Afterwards, we have reviewed the different drug delivery systems designed until now, i.e. high-density, intragastric floating, expandable, superporous hydrogel, mucoadhesive and magnetic systems. Finally, we have focused on gastroretentive dosage forms especially designed against H. pylori, including specific targeting systems against this bacterium.

Characterization of transport of chlorhexidine-loaded nanocapsules through hairless and wistar rat skin.

Nanocapsules appear a promising approach as a drug system for topical application. However, the transport mechanism of nanocapsule-associated drug through the skin is still being questioned. In the present study, the transport of chlorhexidine-loaded poly(epsilon-caprolactone) nanocapsules through full-thickness and stripped hairless rat skin was investigated in static-diffusion cell. The chlorhexidine permeation profiles fitting the Fickian diffusion model showed that the drug encapsulation reduced the percutaneous drug absorption through stripped skin. Possible nanocapsule transport within skin conducts was suggested from the analysis of permeation parameters and confirmed by confocal laser microscopy studies. Furthermore, the chlorhexidine permeation and drug release data were highly correlated, suggesting that the magnitude of percutaneous absorption was controlled by the diffusion across the polymeric carrier. The behavior of nanocapsules at the skin interface was investigated by contact angle and surface tension measurements. The small 'wetting' of the nanocapsule on the stratum corneum surface preserved the mechanical integrity of the carrier characterized by a high specific surface at the skin interface. The flexibility of the nanocapsules assured a satisfying bioadhesion to the skin, whereas the rigidity of the carrier limited the molecular 'spill' into the skin and controlled the drug delivery to the skin.

Molecular organization of the human serotonin transporter at the air/water interface.

The serotonin transporter (SERT) is the target of several important antidepressant and psychostimulant drugs. It has been shown that under defined conditions, the transporter spread at the air/water interface was able to bind its specific ligands. In this paper, the interfacial organization of the protein has been assessed from dynamic surface pressure and ellipsometric measurements. For areas comprising between 10,400 and 7,100 A(2)/molecule, ellipsometric measurements reveal an important change in the thickness of the SERT film. This change was attributed to the reorientation of the transporter molecules from a horizontal to their natural predictive transmembrane orientation. The thickness of the SERT film at 7,100 A(2)/molecule was found to be approximately equal to 84 A and coincided well with the theoretical value estimated from the calculations based on the dimensions of alpha-helices containing membrane proteins. These data suggest that the three-dimensional arrangement of the SERT may be represented as a box with lengths d(z)=83--85 A and d(y) or d(x)=41--47 A.

Fucosyled neoglycolipids: synthesis and interaction with a phospholipid.

The interfacial behavior of the neoglycolipids formed of Guerbet alcohol (G(28)) bound to a triethylene glycol spacer (E(3)) and to a sugar moiety (alpha- and beta-fucose) spread at the air/water interface has been studied under dynamic conditions of compression. Although the alpha (alpha-FucE3G28)- and beta-fucose (beta-FucE3G28) derivatives possessed the same chemical structure, the positioning of the sugar moiety relative to the whole molecule had a significant influence on the organization of neoglycolipid molecules in the spread monolayers. Thus, beta-fucose molecules exhibited higher compressibilities and larger molecular areas than a alpha/beta (84/16%) mixture (alpha(84)-FucE3G28). The comparison of the compressional behavior of the fucose derivatives with that of Guerbet alcohol in the absence and in the presence of the triethylene glycol spacer shows that the presence of the E(3) chain is necessary to stabilize the lipid at the interface and that the incorporation of a sugar moiety into the molecule resulted in an important expansion of a monolayer. Despite their different interfacial behaviors, the two sugar derivatives formed ideal mixtures when cospread at the air/water interface. Conversely, in the presence of a phospholipid, such as DMPC, repulsive interactions were observed and appeared to be stronger for DMPC/alpha(84)-FucE3G28 mixed monolayers. The membrane fluidity of DMPC liposomes bearing the studied amphiphilic molecules was assessed by fluorescence depolarization measurements. The results reveal that whereas G(28) was deeply inserted into the liposome bilayers, the presence of a E(3) chain and of a sugar moiety in these bilayers induced a transfer of the amphiphilic derivatives from the hydrophobic core towards polar headgroups of phospholipid molecules.

Assessment of immunological status in the critically ill.

The systemic inflammatory response (SIRS) results from various types of injuries such as severe infection, trauma, ischemia-reperfusion and major surgery including cardiac surgery with cardio-pulmonary bypass. This response involves immune cell activation and a complex network of proinflammatory cytokines, which may induce multiple organ failure when uncontrolled. The monocyte plays a central role in the response to infection with the release of TNF, IL-1, and IL-12. In addition, monocytes present antigens to T lymphocytes. An optimal antigen presentation requires the expression of MHC class II HLA-DR on monocytes surface and of co-stimulatory molecules such as CD54 on monocytes and LFA-1 on lymphocytes. It has become increasingly apparent that the pro-inflammatory response is balanced by concomitant anti-inflammatory mechanisms that results in monocyte deactivation, characterized by a decrease in HLA-DR expression and the release of anti-inflammatory cytokines such as IL-10. This counterregulatory response, if prolonged or predominant, may predispose the patient to a higher risk of infection. Further studies need to be conducted to precise: 1) the intensity of depression of the surface molecule expression assessing monocyte function, such as HLA DR and CD54; 2) the level of IL-10 and IL-12 release in patients with severe sepsis; 3) the immunomodulating effects of frequently used treatments in these patients with severe sepsis and in surgical patients; 4) the time course of recovery; 5) if the monitoring of HLA-DR, CD54, IL-10 and IL-12 will better predict the clinical outcome than clinical parameters.

Ligand interaction with the purified serotonin transporter in solution and at the air/water interface.

The purified serotonin transporter (SERT) was spread at the air/water interface and the effects both of its surface density and of the temperature on its interfacial behavior were studied. The recorded isotherms evidenced the existence of a stable monolayer undergoing a lengthy rearrangement. SERT/ligand interactions appeared to be dependent on the nature of the studied molecules. Whereas an unrelated drug (chlorcyclizine) did not bind to the spread SERT, it interacted with its specific ligands. Compared to heterocyclic drugs, for which binding appeared to be concentration-dependent, a 'two-site' mechanism was evidenced for pinoline and imipramine.

Assessment of immunological status in the critically ill.

The systemic inflammatory response (SIRS) results from various types of injuries such as severe infection, trauma, ischemia-reperfusion and major surgery including cardiac surgery with cardio-pulmonary bypass. This response involves immune cell activation and a complex network of proinflammatory cytokines, which may induce multiple organ failure when uncontrolled. The monocyte plsys a central role in the response to infection with the release of TNF-alpha, IL-1 beta, and IL-12. In addition, monocytes present antigens to T lymphocytes. An optimal antigen presentation requires the expression of MHC class II HLA-DR on monocytes surface and of costimulatory molecules such as CD54 on monocytes and LFA-1 on lymphocytes. It has become increasingly apparent that the proinflammatory response is balanced by concomitant anti-inflammatory mechanisms that results in monocyte deactivation, characterized by a decrease in HLA-DR expression and the release of anti-inflammatory cytokines such as IL-10. This counterregulatory response, if prolonged or predominant, may predispose the patient to a higher risk of infection. Further studies need to be conducted to precise: i) the intensity of depression of the surface molocule expression assessing monocyte function, such as HLA DR and CD54; ii) the level of IL-10 and IL-12 release in patients with severe sepsis; iii) the immuno-modulating effects of frequently used treatments in these patients with severe sepsis and in surgical patients; iv) the time course of recovery; v) if the monitoring of HLA-DR, CD54, IL-10 and IL-12 will better predict the clinical outcome than clinical parameters.