[Changes in kaliemia following rapid sequence induction with succinylcholine in critically ill patients].

Objective: Evaluate the changes in potassium following rapid sequence induction with succinylcholine in critically ill-patients and determine whether hospital length of stay could influence the succinylcholine-induced hyperkaliemia.

Study Design: Prospective and observational study.

Patients And Methods: After approval by our local ethical committee, we prospectively included 36 patients admitted from more than 24hours in ICU and who required succinylcholine for rapid tracheal intubation (1mg/kg).

Ambivalent role of the innate immune response in rabies virus pathogenesis.

The neurotropic rabies virus (RABV) has developed several evasive strategies, including immunoevasion, to successfully infect the nervous system (NS) and trigger a fatal encephalomyelitis. Here we show that expression of LGP2, a protein known as either a positive or negative regulator of the RIG-I-mediated innate immune response, is restricted in the NS. We used a new transgenic mouse model (LGP2 TG) overexpressing LGP2 to impair the innate immune response to RABV and thus revealed the role of the RIG-I-mediated innate immune response in RABV pathogenesis.

Secreted dengue virus nonstructural protein NS1 is an atypical barrel-shaped high-density lipoprotein.

Dengue virus (DENV) causes the major arboviral disease of the tropics, characterized in its severe forms by signs of hemorrhage and plasma leakage. DENV encodes a nonstructural glycoprotein, NS1, that associates with intracellular membranes and the cell surface. NS1 is eventually secreted as a soluble hexamer from DENV-infected cells and circulates in the bloodstream of infected patients.

Attenuation of rabies virulence: takeover by the cytoplasmic domain of its envelope protein.

The capacity of a rabies virus to promote neuronal survival (a signature of virulence) or death (a marker of attenuation) depends on the cellular partners recruited by the PDZ-binding site (PDZ-BS) of its envelope glycoprotein (G). Neuronal survival requires the selective association of the PDZ-BS of G with the PDZ domains of two closely related serine-threonine kinases, MAST1 and MAST2. Here, we found that a single amino acid change in the PDZ-BS triggered the apoptotic death of infected neurons and enabled G to interact with additional PDZ partners, in particular the tyrosine phosphatase PTPN4.

Toll-like receptor 3 (TLR3) plays a major role in the formation of rabies virus Negri Bodies.

Human neurons express the innate immune response receptor, Toll-like receptor 3 (TLR3). TLR3 levels are increased in pathological conditions such as brain virus infection. Here, we further investigated the production, cellular localisation, and function of neuronal TLR3 during neuronotropic rabies virus (RABV) infection in human neuronal cells.

Detrimental contribution of the immuno-inhibitor B7-H1 to rabies virus encephalitis.

Rabies virus is the etiological agent of an acute encephalitis, which in absence of post exposure treatment is fatal in almost all cases. Virus lethality rests on its ability to evade the immune response. In this study, we analyzed the role of the immuno-inhibitory molecule B7-H1 in this virus strategy.

Modulation of HLA-G and HLA-E expression in human neuronal cells after rabies virus or herpes virus simplex type 1 infections.

Human Leukocyte Antigen (HLA)-G and E are nonclassical human MHC class I molecules. They may promote tolerance leading to virus and tumor immune escape. We recently described that the herpes simplex virus type 1 (HSV-1), a neurotropic virus inducing chronic infection and neuron latency, and rabies virus (RABV), a neuronotropic virus triggering acute neuron infection, up-regulate HLA-G expression in human neurons (NT2-N).

The innate immune facet of brain: human neurons express TLR-3 and sense viral dsRNA.

Inflammation is an important factor in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease or multiple sclerosis, and during microbial infections of the nervous system. Glial cells were thought to be the main contributor for cytokine and chemokine production and Toll-like receptor (TLR) expression in the brain. Here, we report that human neurons express TLR-3, a major receptor in virus-mediated innate immune response.

Modulation of HLA-G expression in human neural cells after neurotropic viral infections.

HLA-G is a nonclassical human major histocompatibility complex class I molecule. It may promote tolerance, leading to acceptance of the semiallogeneic fetus and tumor immune escape. We show here that two viruses-herpes simplex virus type 1 (HSV-1), a neuronotropic virus inducing acute infection and neuron latency; and rabies virus (RABV), a neuronotropic virus triggering acute neuron infection-upregulate the neuronal expression of several HLA-G isoforms, including HLA-G1 and HLA-G5, the two main biologically active isoforms.

Virus infection switches TLR-3-positive human neurons to become strong producers of beta interferon.

To study the capacity of human neurons to mount innate immunity responses to viral infections, we infected cells of a human postmitotic neuron-derivative cell line, NT2-N, with rabies virus (RABV) and herpes simplex type 1 (HSV-1). Changes in neuronal gene expression were analyzed by use of Affymetrix microarrays. Applying a twofold cutoff, RABV increased the transcription of 228 genes, and HSV-1 increased the transcription of 263 genes.

Immunopotentiation of the antibody response against influenza HA with apoptotic bodies generated by rabies virus G-ERA protein-driven apoptosis.

Apoptosis is considered to be a way of eliminating unwanted cells without causing major inflammation. Nevertheless, several lines of evidence show that apoptotic cell-derived antigens can be strong immunogens. The rabies virus glycoprotein G-ERA is an apoptotic molecule.

Mapping of a dengue virus neutralizing epitope critical for the infectivity of all serotypes: insight into the neutralization mechanism.

Dengue virus infections are a growing public health concern and strategies to control the spread of the virus are urgently needed. The murine monoclonal antibody 4E11 might be of interest, since it neutralizes dengue viruses of all serotypes by binding to the 296-400 segment of the major dengue virus envelope glycoprotein (DE). When phage-displayed peptide libraries were screened by affinity for 4E11, phage clone C1 was selected with a 50% frequency.

Dengue virus type 1 nonstructural glycoprotein NS1 is secreted from mammalian cells as a soluble hexamer in a glycosylation-dependent fashion.

Nonstructural glycoprotein NS1, specified by dengue virus type 1 (Den-1), is secreted from infected green monkey kidney (Vero) cells in a major soluble form characterized by biochemical and biophysical means as a unique hexameric species. This noncovalently bound oligomer is formed by three dimeric subunits and has a molecular mass of 310 kDa and a Stokes radius of 64.4 A.

A recombinant Fab neutralizes dengue virus in vitro.

A recombinant Fab that recognizes a neutralizing epitope located in the (296-400) region of protein E of dengue virus was obtained from cloned hybridoma cells secreting the mouse monoclonal antibody (mAb) 4E11. The Fd and light chain antibody genes were amplified by polymerase chain reaction, cloned into the phagemid vector pMad, expressed in bacteria to produce Fab fragments and sequenced. The mAb 4E11, in particular its light chain complementary-determining regions, shared homologies with two other anti-viral mAbs.

Affinity-purified dengue-2 virus envelope glycoprotein induces neutralizing antibodies and protective immunity in mice.

We constructed a recombinant baculovirus which produces a dengue (DEN)-2 virus envelope (E) protein containing a six-histidine (H6) tag in place of the last 100 amino acids at its C-terminus. The recombinant protein was purified from the supernatant of baculovirus-infected Spodoptera frugiperda insect cell cultures to apparent homogeneity by cation-chelation chromatography (TALON) in which the H6-tagged E-protein was eluted under non-denaturing conditions with 100 mM imidazole at pH 8.0.

Dengue 1 virus binding to human hepatoma HepG2 and simian Vero cell surfaces differs.

We analysed the binding and infectivity of dengue virus serotype 1 (DEN-1) for the human hepatoma cell line HepG2 in comparison with the simian kidney cell line Vero. The higher susceptibility of Vero cells to DEN-1 correlated with greater binding affinity of DEN-1 to these cells. In contrast, the capacity of virus attachment was higher for HepG2 than for Vero cells.

Identification of helper T cell epitopes of dengue virus E-protein.

The T cell proliferative response to dengue 2 (Jamaica) E-glycoprotein (495 amino acids) was analyzed in vitro using either killed virus or E-protein fragments or synthetic peptides. Inactivated dengue virus stimulated dengue-specific lymph node (LN) CD4+T cell proliferation in BALB/c (H-2d), C3H (H-2k) and DBA/1 (H-2q) but not in C57BL/6 (H-2b) mice. Moreover, LN cells from dengue-virus primed BALB/c mice proliferated in vitro in response to three purified non-overlapping E-protein fragments expressed in E.

Use of recombinant fusion proteins and monoclonal antibodies to define linear and discontinuous antigenic sites on the dengue virus envelope glycoprotein.

Sixteen overlapping fragments of the dengue-2 virus envelope (E) protein, expressed as trpE-E fusion products in Escherichia coli, were used to map the epitopes defined by a panel of 20 monoclonal antibodies (MAbs) by immunoblotting. Using this technique, the amino acid sequence of six antigenic domains on the E protein was characterized. Nonneutralizing MAbs were found to define either linear-specific, subcomplex-specific (amino acids 22-58), and complex-specific (amino acids 304-332) epitopes or a subcomplex conformational-dependent epitope requiring the presence of two closely linked amino acid sequences from the E protein, 60-97 and 298-397.

Processing, secretion, and immunoreactivity of carboxy terminally truncated dengue-2 virus envelope proteins expressed in insect cells by recombinant baculoviruses.

Two recombinant baculoviruses were constructed by inserting via the transfer vector pAcYM1 the genes coding for the structural proteins of dengue (DEN)-2 virus downstream from the polyhedrin promoter of Autographa californica nuclear polyhedrosis virus. The two recombinants differed in truncation of 26 and 71 amino acids, respectively, in the carboxy-terminal sequence of DEN-specific envelope (E) glycoprotein. Recombinant DEN-2 E glycoproteins were processed and transported to the surface of Spodoptera frugiperda Sf9 cells infected with both viruses.

Modulation of leukotriene generation by pertussis toxin.

The purpose of our study was to characterize the properties of the interaction of pertussis toxin with human polymorphonuclear leukocytes for the modulation of leukotriene generation and metabolism. The cells were stimulated with either the Ca ionophore A23187, opsonized zymosan, or the bacterial peptide formyl-methionyl-leucyl phenylalanine. Incubation of the cells with pertussis toxin led to a rapid inhibition of LTB4 generation when formyl-methionyl-leucyl phenylalanine was used as the stimulus, whereas there was no effect with the Ca ionophore and just a low effect with opsonized zymosan.

Solid phase enzyme immunoassays of pertussis toxin using peroxidase or biotin labelled antibodies.

The quantitative determination of pertussis toxin (PT) is generally estimated by biological tests which are time-consuming, cumbersome and unsuitable for simultaneous testing of a large number of samples. The present work describes a rapid and sensitive ELISA procedure allowing PT assay based on a sandwich technique amplified via avidin-biotin interaction. As low as 0.

Pertussis toxin facilitates the progesterone-induced maturation of Xenopus oocyte. Possible role of protein phosphorylation.

Progesterone triggers the first meiotic cell division of Xenopus oocyte and inhibits cAMP synthesis. The effect of pertussis toxin purified from Bordetella pertussis was tested on the maturation of Xenopus oocyte. The toxin did not inhibit progesterone-induced resumption of meiosis or the hormone-induced drop in cAMP level.

Comparative toxicity, protective, histamine sensitizing and leucocytosis promoting activities in mice of Bordetella pertussis culture fluid, bacterial cells and cell extracts.

Bordetella pertussis bacterial cells, bacterial extracts, and concentrated culture supernatant fluid were comparatively examined for histamine sensitizing and leucocytosis promoting activities, toxicity (mouse weight gain test), immunoprotective potency and lipopolysaccharide bioassay. The activity of histamine sensitizing factor always paralleled that of leucocytosis promoting factor. In contrast, important differences were demonstrated regarding the toxicity and protective activity of the three preparations.

[Pertussis toxin stimulates brain adenyl cyclase and induces ADP ribosylation of a 40,000 dalton membrane protein].

The adenylate cyclase activity of Rat brain synaptosomal membranes is strongly activated by forskolin. This study demonstrates: 1. That GTP or its analogs, when added to forskolin, decrease the enzyme stimulation by a factor of 40 to 60%; 2.