Validation of in vitro-produced and freeze-dried whole cell lysate antigens for ELISA Trypanosoma evansi antibody detection in camels

Trypanosoma evansi is a blood parasite responsible for surra in mammals, with a high impact in camels and horses. The WOAH-recommended reference method for detecting immunoglobulin G directed against T. evansi is ELISA, using whole cell lysate antigens (WCLAs). WCLAs are prepared with T. evansi produced in laboratory rodents, separated from blood cells using DE-cellulose anion exchange chromatography. As parasite lysates are fragile, antigens are preserved frozen pending use. For these reasons and others, T. evansi WCLAs are not commercially available. They are produced in small quantities, in a limited number of specialized laboratories, and they require a reliable and expensive cold chain for their shipment. In this study, we assessed and validated in vitro production of T. evansi and lyophilization of WCLAs in comparison with the reference method using frozen WCLAs prepared with parasites produced in rodents. Using a set of 400 samples monthly collected from 12 naturally infected camels followed-up for 1384 days, and two batches of referenced serum samples (infected, n = 12; non-infected, n = 15), statistical studies on qualitative and semi-quantitative results of the ELISAs did not show any significant difference when comparing the four combinations of parasites produced in vivo or in vitro, and frozen or freeze-dried WCLSAs. A repeatability study (28 repeats in 9 serum samples) was fully satisfying (p-value = 0.055). With the more convenient in vitro-produced freeze-dried WCLAs it was possible to: (i) avoid the ethical concern of in vivo production, (ii) improve the standardization of antigen production, (iii) secure antigen preservation during shipment and (iv) save a considerable amount of money (DE52-cellulose and dry-ice cold chain being avoided). Additional studies with other Trypanosoma spp are required for further extending ELISA to regional laboratories in enzootic areas, especially in view of the current progress in the "Progressive Control Pathway" (PCP) for trypanosomes in Africa.

Consistent Kaluza-Klein Truncations and Two-Dimensional Gauged Supergravity

We consider generalized Scherk-Schwarz reductions of E_{9} exceptional field theory to D=2 space-time dimensions and, in particular, construct the resulting scalar potential of all gauged supergravities that can be obtained in this way. This provides the first general expression for a multitude of theories with an interesting structure of vacua, covering potentially many new AdS_{2} cases. As an application, we prove the consistency of the truncation of eleven-dimensional supergravity on S^{8}×S^{1} to SO(9) gauged maximal supergravity. Fluctuations around its supersymmetric SO(9)-invariant vacuum describe holographically the dynamics of interacting D0-branes.

In vitro Activity of a Novel Series of Polyoxosilicotungstates against Human Myxo-, Herpes- and Retroviruses

A series of silicon-containing polyoxotungstates belonging to the ‘Keggin-type’ (‘Keggin’, ‘Keggin sandwich’) were evaluated for their antiviral activity against enveloped viruses (myxo-, herpes- and retroviruses). The compounds exhibited antiviral activity against influenza virus type A, respiratory syncytial virus (RSV), herpes simplex virus type-1 (HSV-1), type-2 (HSV-2), thymidine kinase-deficient (TIC) HSV-1, human cytomegalovirus (HCMV), human immunodeficiency virus type-1 (HIV-1) and type-2 (HIV-2) at concentrations that were well below their cytotoxic threshold. The ‘Keggin’ compound JM2815 (K5[Si-(TiCp)W11O39].12H2O) and the ‘Keggin sandwich’ compound JM1590 (K13[Ce(SiW11O39)2].26H2O) resulted in the highest selectivity indices against HIV-1 and HIV-2, and compound JM2820 ([Me3NH]8.[Si2Nb6W18O77]) was the most potent inhibitor of HSV and HCMV replication. These compounds proved active against HCMV and HSV when present during virus adsorption, and against influenza virus A and RSV when present after virus adsorption. Polyoxosilicotungstates inhibited the binding of radiolabeled HCMV particles to the cells at concentrations that were antivirally active, and the compounds were able to displace HCMV particles that were bound to a heparin-Sepharose matrix. Presumably, the polyoxosilicotungstates interact with positively charged domains on the viral envelope site(s) involved in the attachment of the (HCMV) virions to the cell surface receptor heparan sulphate.

Stress (Tako-tsubo) cardiomyopathy in critically-ill patients

BACKGROUND

Stress cardiomyopathy (SC) is a transient ventricular dysfunction rarely described in the critical care setting.

OBJECTIVE

To evaluate the mechanisms, incidence, treatment and prognosis of SC.

METHOD

This is a retrospective observational study of every critically-ill patient admitted to the ICU over a period of two years.

RESULTS

Among 1314 patients admitted in the ICU, 20 patients (1.5%) were diagnosed with SC. A total of 249 patients experienced cardiogenic shock, whereas 8% were suffering from SC. SC was suspected because of hemodynamic impairment (80% of cases), ECG modifications (15%) and/or dyspnea (15%). SC was apical (typical Tako-tsubo) in 90% and atypical in 10% of cases. Several mechanisms or conditions may explain the occurrence of SC and are may be combined: catecholamine toxicity (45%), psychological stress, seizures or neurological impairment (35%), non-epicardial coronary ischemia (20%) and left ventricular outflow track (LVOT) obstruction (10%). SC could have indirectly caused death by worsening heart failure in three patients and arrhythmias were seen in 40% of patients. SAPS2, renal impairment, malnutrition, norepinephrine infusion and thrombocytopenia were associated with death in the univariate analysis. Catecholamines were required in 85% and intra-aortic balloon pump in 20% of patients.

CONCLUSIONS

SC is a rare reversible cardiac impairment in the critically-ill patient that can induce arrhythmias and cardiogenic shock. The likely mechanisms are combined: catecholamine toxicity, stress or neurological involvement and less frequently ischemia or LVOT obstruction.

CHADS2 and CHA2DS2-VASc scores can predict thromboembolic events after supraventricular arrhythmia in the critically ill patients

PURPOSE

Prediction of arterial thromboembolic events (ATEs) in relation to supraventricular arrhythmia (SVA) has been poorly investigated in the intensive care unit (ICU). We aimed at evaluating CHADS2 and CHA2DS2-VASc scores to predict SVA-related ATE in the ICU.

METHODS

We conducted a prospective observational study including all the patients except those in the postoperative course of cardiac surgery who presented SVA lasting 30 seconds or longer during their ICU stay. We looked for ATE during ICU stay, at the first and sixth month of follow-up after ICU discharge.

RESULTS

During the 15-month study period, 108 (12.8%) of 846 ICU patients experienced SVA with 12 SVA-related ATE occurring 6 days (3; 13) (median, 10%-90% percentiles) after SVA onset. In our SVA patients, CHADS2 score was 2 (0; 5), and CHA2DS2-VASc score 3 (0; 7). Both CHADS2 (odds ratio (OR), 1.6 [1.1; 2.4]; P = .01) and CHA2DS2-VASc scores (OR, 1.4 [1.04; 1.8]; P = .03) were significantly associated with ATE onset. However, the most accurate threshold for predicting ATE was CHADS2 score of 4 or higher. Using a multivariate analysis, only patient's history of stroke was associated with ATE onset (OR, 9.2 [2.4; 35]; P = .001).

CONCLUSION

CHADS2 and CHA2DS2-VASc scores are predictive of SVA-related thromboembolism in the critically ill patient.

[Severe cases of A(H1N1)v2009 infection in Réunion Island in 2009 and 2010]

Dans l’hémisphère sud, La Réunion est la sentinelle des infections survenant préférentiellement au cours de l’hiver austral, susceptibles de gagner quelques mois plus tard l’hémisphère nord, telle l’infection à A(H1N1)v2009. Nous rapportons les caractéristiques des patients admis en 2009 et 2010 dans notre service de réanimation principalement pour détresse respiratoire aiguë, à la suite d’une infection à A(H1N1)v2009. Les données démographiques, cliniques, biologiques, ainsi que les traitements et le devenir des patients admis pour infection virale à A(H1N1)v2009 exclusivement confirmée par RT-PCR ont été recueillis de façon prospective. Au cours des années 2009 et 2010, 25 patients ont répondu aux critères définis d’infection à A(H1N1)v2009. L’âge médian était de 40,4 (±17,4) ans. La plupart d’entre eux (22/25) présentaient des facteurs de comorbidité: pathologies chroniques, surpoids ou obésité, grossesse, trisomie. Les principaux motifs d’admission en réanimation ont été les pneumonies virales avec tableau de syndrome de détresse respiratoire aiguë. Le recours à la ventilation artificielle a été nécessaire chez 22 des 25 patients, avec recours à des méthodes sophistiquées et réservées à quelques centres au niveau national, telles que les techniques d’oxygénation extracorporelle (ECMO) ou ventilation à haute fréquence (HFO). Au cours des deux années, 12 décès (48 %) sont survenus essentiellement dans des tableaux de défaillance multiviscérale. Au cours des hivers et automnes australs 2009 et 2010 et pendant une période de plusieurs semaines, l’infection à A(H1N1) v2009 a entraîné une surcharge d’activité notable dans les services de réanimation de La Réunion. L’échec de la campagne de vaccination, notamment des personnes à risques, a eu pour conséquence la survenue de nouveaux cas graves en 2010, notamment parmi les personnes à risques. Le recueil de ces données peut aider à la planification et à l’anticipation de la prise en charge d’autres épidémies grippales.

[Medical paediatric simulation: a European survey]

OBJECTIVE

To present the effective applications of paediatric medical simulation in terms of education, evaluation, density, development, goals and constraints.

STUDY DESIGN

Survey realized within 38 paediatric simulation centres (PSC) in Europe, identified by Web search and through the Society in Europe for Simulation Applied to Medicine (SESAM.

RESULTS

Twenty centers answered the questionnaire (52%). Ninety-four percent of the PSC had beforehand acquired an experience of adult medical simulation, 94.6% of the PSC were created before 2006. Ninety percent of the PSC owned at least one high-fidelity pediatric simulator. The 80% of the PSC indicated multiple funding sources. Eighty percent of the PSC had at least one specific instructor for the paediatric simulation (average=2.7 paediatric instructors per centre). The PCS reported to get onto various topics: neonatology (25% of the PCS), prehospital medicine (36.8%), paediatric anaesthesiology (74%) and paediatric intensive care (89%). Simulation allowed 70% of the centers to lead some research project. Ninety-five percent of the centers agreed about an European collaboration on research projects or about the mutualization of the created scenarios.

CONCLUSION

The material, financial and human means of the interviewed centres are consequential but heterogeneous in Europe. MSP offers numerous and various application fields and generates some research activity.