[Moods in critical care units: emotions and moral duties of care providers]. / États d'âme en réanimation COVID-19 : des émotions aux devoirs moraux des acteurs du soin.

The Covid-19 pandemic instills emotions that can be understood in the pathological sense of mental disorder and/or in the heuristic sense of a moral dimension. So what about this distinction in critical care and resuscitation services where caregivers are at the forefront of events? What to do with emotions? The objective of this work is to pose a medico-psychological and ethical perspective on these questions, starting from the hypothesis that emotions have a specific use during the pandemic. The first step will be to show that anguish and fear, although different from an epistemological point of view, arise from the same historical place, which is the discourse of the medical world with death. The awareness of the inevitable makes share the same need of the caregiver and the citizen of a psychic economy which will lead to differentiating two possible reactions to emotions: one to face up and one to come to terms with. This psychic interlacing, inherent to the pandemic context, calls for critical care on a moral dimension related to the issue of abandonment of the human person and the poorly understood notion of "mass death". An answer to this difficulty would be found in the concept of "being-caregiver-close" but its application also supposes an ethical reflection on the outlets and the personal virtues.

[Deployment of a mobile RT-PCR laboratory molecular biology to deal with the A(H1N1) challenge in Kaboul]. / Déploiement d'un laboratoire mobile de biologie moléculaire face au défi A(H1N1) à Kaboul.

Since October 2009, the fear of swine flu spread in Afghanistan and severe cases were observed among NATO soldiers. Two patients were hospitalized in an Intensive Care Unit. To face this new challenge, the French Health Service decided the deployment of a mobile RT-PCR laboratory molecular biology in the Kabul International Military Hospital. We describe the implementation of the mobile RT-PCR laboratory for the diagnosis of A(H1N1). The analysis of the first nasopharyngeal samples confirmed the presence of this virus in Afghanistan. The peak of positive cases was observed in mid-November 2009, and some cluster cases were observed among units deployed on the field.

[Convulsions induced by ropivacaine after midhumeral block]. / Convulsions induites par la ropivacaïne lors d'un bloc au canal huméral.

We report a case of central nervous system toxicity induced by ropivacaine following a brachial block at the humeral canal. Forty millilitres 0.75% ropivacaine (4.28 mg.kg-1) were used uneventfully, with slow injections and negative intermittent aspirations. Fifteen minutes later, the patient presented two episodes of generalised convulsions treated by diazepam, 20 mg. The total venous ropivacaine concentration measured two hours after the block was 2.3 mg.l-1.

[Chance discovery of methanol poisoning during a state of inebriation]. / Découverte fortuite d'une intoxication au méthanol lors d'un état d'ébriété.

We report a case of wood alcohol (methylated spirits) poisoning in a 40-year-old chronic alcoholic. The initial diagnosis of state of drunkenness was supported by the increased plasma level of ethanol (4.66 g.L-1) obtained with enzymatic method. The confirmation, using gas chromatography (GC), showed an unexpected peak with a retention time at 1.19 min, characteristic of methanol (0.41 g.L-1). The GC analysis of the absorbed beverage revealed a 5% methanol content. The osmolal gap was 115 mOsm.kg-1, with 13 mOsm.kg-1 due to methanol and 90 mOsm.kg-1 to ethanol. Seven hours after the ingestion, the anion gap was at 13 mmol-1. This result reflected the inhibition of methanol oxidation by alcohol-dehydrogenase, when the plasma ethanol concentration was above 1 g.L-1. This concentration was maintained by continuous intravenous administration of (Curéthyl-A) a 95% ethanol containing solution, until methanol concentration decreased below 0.2 g.L-1. The outcome was favourable without neurological and ophthalmological sequelae.

[Suprascapular palsy: a complication of surgical positioning?]. / Paralysie sus-scapulaire: une complication de la posture opératoire?

We report a case of persisting suprascapular nerve palsy after surgery under general anaesthesia of short duration in a conventional position. Surgical exploration, eight months later, showed a suprascapular notch narrowed by a hypertrophied and calcified superior transverse ligament. Such a lesion and the practice of volley-ball by the patient are in favour of a pre-existing infraclinical neuropathy.

[Remifentanil: postoperative respiratory depression after purging of the infusion line]. / Rémifentanil: dépression respiratoire postopératoire à l'occasion d'une purge de la tubulure de perfusion.

We report a case of postoperative apnoea in the recovery room, 25 minutes after tracheal extubation, in a fully awake patient. This event occurred after flushing of an obstructed IV line into which remifentanil had been injected through a 3-way stopcock during anaesthesia. The means for prevention of such an adverse event are discussed.

Crucial domains are conserved in Enterobacteriaceae porins.

With the recent resolution of the crystal structures of several bacterial porins, it is worthwhile to define the generality of their organization throughout the Enterobacteriaceae. The distribution of specific epitopes was analysed among various Gram-negative bacterial porins using anti-peptide antibodies specific to exposed, transmembrane spanning, or pore-forming regions of Escherichia coli porins. Anti-peptide antibodies which recognized the exposed epitopes indicated a great variability among the bacterial porins analysed. Interestingly, an antigenic site located in the internal loop L3 constricting the pore diameter was present in the majority of the bacterial porins tested. Two epitopes located in domains involved in subunit interaction were also highly conserved. The presence of these common peptides suggested a conservation of specific regions involved in the functional organization of the enterobacterial porins.

[Chatergee syndrome and anesthesia. Apropos of a case]. / Syndrome de Chattergee et anesthésie. A propos d'un cas.

A combination of complete left bundle branch block (LBBB) and symmetrical negative T waves on the ECG characterizes the Chattergee syndrome. This pattern is infrequently and fortuitously detected in the absence of clinical symptoms. However, when appearing during general anaesthesia, it may lead to diagnostic difficulties to rule out a myocardial ischaemia. One case of this pattern was observed near the end of an otherwise non-complicated cholecystectomy in a ASA II 45 year old man, ECG abnormalities lasted for only a short time. Recovery and outcome were uneventful. Investigations were negative except for an early LBBB during the exercise test. Echocardiography and coronarography were normal. No therapy was given. In such perioperative cases, it is recommended to keep a very cautious attitude and to search for an incipient coronary disease which cannot be completely excluded in some cases.

Structural and functional alterations of a colicin-resistant mutant of OmpF porin from Escherichia coli.

A strain of Escherichia coli, selected on the basis of its resistance to colicin N, reveals distinct structural and functional alterations in unspecific OmpF porin. A single mutation [Gly-119-->Asp (G119D)] was identified in the internal loop L3 that contributes critically to the formation of the construction inside the lumen of the pore. X-ray structure analysis to a resolution of 3.0 A reveals a locally altered peptide backbone, with the side chain of residue Asp-119 protruding into the channel, causing the area of the constriction (7 x 11 A in the wild type) to be subdivided into two intercommunicating subcompartments of 3-4 A in diameter. The functional consequences of this structural modification consist of a reduction of the channel conductance by about one-third, of altered ion selectivity and voltage gating, and of a decrease of permeation rates of various sugars by factors of 2-12. The structural modification of the mutant protein affects neither the beta-barrel structure nor those regions of the molecule that are exposed at the cell surface. Considering the colicin resistance of the mutant, it is inferred that in vivo, colicin N traverses the outer membrane through the porin channel or that the dynamics of the exposed loops are affected in the mutant such that these may impede the binding of the toxin.

Involvement of exposed polypeptide loops in trimeric stability and membrane insertion of Escherichia coli OmpF porin.

Different ompF-ompC gene fusions were used to analyse the regions involved in the stable trimerization and membrane insertion of the Escherichia coli OmpF porin. The stability of the trimers formed from the various hybrids was analysed. Three classes of trimer instability are observed related to the presence of different exposed polypeptide loops of OmpF. In all cases, amino acids located between residue 115 and residue 144 of OmpF are necessary to promote a correct and stable trimeric conformation. However, immunogold labelling studies indicate the correct insertion of the protein in the outer membrane despite a marked instability of some hybrid porins. The location of the residues involved in trimer stability is discussed with regards to both the three-dimensional structure and the folding of OmpF.

The orientation of porin OmpF in the outer membrane of Escherichia coli.

The in vivo orientation of the channel forming porin OmpF from the outer membrane of Escherichia coli was assessed by immunological, biochemical and structural techniques. Porin OmpF exists as a trimer of channels formed by 16 antiparallel beta-strands. These are connected by long hydrophilic loops on one side of the bilayer and short loops or beta-turns on the other. The former constitute the rough side of the porin channel, the latter the smooth side. Epitopes at the cell surface have all been mapped within the long loops, suggesting a rough-side-out orientation of OmpF in the membrane. We analyzed detergent solubilized OmpF trimers, reconstituted 2-D OmpF crystals, OmpF containing outer membranes (sacculi) and intact cells of an E. coli strain overexpressing OmpF. Both solubilized OmpF and OmpF containing sacculi were exposed to proteases, and distinct cleavage sites were identified by protein sequencing. Solubilized OmpF, reconstituted 2-D OmpF crystals and detergent extracted sacculi were tested for their capacity to adsorb colicin N. We used antibodies directed against surface exposed epitopes for immunogold labeling of reconstituted 2-D OmpF crystals and sacculi. The surfaces of intact cells and extracted sacculi were analyzed by electron microscopy and image processing. Finally, a full 3-D reconstruction of negatively stained OmpF containing sacculi revealed the OmpF trimer in its native conformation within the outer membrane. Colicin N and antibody experiments, as well as the 3-D map of the sacculi demonstrated that OmpF exposes the long loops to the extracellular space. In contrast, reconstituted crystalline OmpF vesicles and double layered sheets were found to be in an inside-out conformation, hence hiding colicin or antibody binding epitopes. Two proteinase K cleavage sites were identified, one on a protruding loop and the other inside the channel on the loop penetrating the pore.

Specific regions of Escherichia coli OmpF protein involved in antigenic and colicin receptor sites and in stable trimerization.

Four different mutations were obtained by selecting for resistance to colicin N and screening for continued production of the OmpF protein of Escherichia coli. Two of them also conferred resistance to colicin A. The substitutions C for R-168 (R168C) and E284K caused the loss of the E21 epitope, while the transition G285D altered the E18, E19, and E20 antigenic sites. The substitution G119D drastically affected the stability of the trimeric conformation.

Immunological cross-reactivity between outer membrane pore proteins of Campylobacter jejuni and Escherichia coli.

Immunocrossreactivity between the major outer membrane protein (MOMP) of Campylobacter jejuni 85H and the OmpC porin of Escherichia coli K-12 was observed. These results indicate that a common antigenic domain is conserved in both MOMP and OmpC. This antigenic region is detected only after a 96 degrees C treatment suggesting that it is buried in the native conformation of the respective porins. In addition, differences were observed between the major outer membrane proteins from various C. jejuni strains. About 60% of the C. jejuni pathogenic strains tested contained a protein exhibiting a similar electrophoretic profile to the 85H porin.

Dynamics of the exposure of epitopes on OmpF, an outer membrane protein of Escherichia coli.

The OmpF protein is the major outer membrane trimeric porin of Escherichia coli B. The exposure of several cell-surface-exposed epitopes, that are recognized by various monoclonal antibodies directed against the protein, is investigated. Kinetic analyses show that two epitopes (E18 and E19) appear early during the in-vivo assembly on the folded monomer, just after the removal of the signal peptide, and are conserved in the native trimer. The trimerization that immediately follows or occurs in conjunction with the folding of monomers exposes another antigenic site (E21) at the surface of metastable forms. The binding of nascent lipopolysaccharide promotes the conversion of the heat-modifiable intermediate to a stable trimer and ensures the exposure of E20, E1, E3, E4 and E7. Late epitopes, E1, E3, E4 and E7 are only detected in the outer membrane fraction. These results suggest that different steps induce the sequential exposure of native antigenic sites. The detection of these epitopes depends on conformational changes occurring during the OmpF insertion into the outer membrane.

Characterization of ompF domains involved in Escherichia coli K-12 sensitivity to colicins A and N.

Various ompF-ompC, ompC-ompF, and ompF-ompC-ompF chimeric genes were used to locate the domains of the OmpF protein involved in cellular sensitivity to colicins. Various parts of the porin participate in the entry of colicins. Colicin N receptor activity was found to require three regions: RN1, located between residues 1 and 63; RN2, located between residues 115 and 262; and RN3, located between residues 279 and 297. The central domain from residues 143 to 262 is involved during the translocation step after the binding step. A large region, including residues 1 to 262, is necessary during colicin A entry. The locations and interactions between these domains specifically required for the uptake of colicins to occur are described and discussed with regard to the homology and topology of the OmpC, OmpF, and PhoE porins.

Immunological approach of assembly and topology of OmpF, an outer membrane protein of Escherichia coli.

Various monoclonal antibodies (MoF) directed against cell-surface-exposed epitopes of OmpF, one major outer membrane pore protein of Escherichia coli B and K-12, have been used to study the assembly and the topology of the protein. This paper firstly describes the characterization of the OmpF epitopes recognized by the various monoclonal antibodies. A comparison between OmpC, OmpF and PhoE porins with respect to their primary amino acid sequence and their cell-surface exposed regions allows us to propose a rough model including 2 antigenic sites. The second part is focused on the assembly of the OmpF protein in the outer membrane. Various forms, precursor, unassembled monomer, metastable oligomer (pre-trimer) and trimer are detected with immunological probes directed against OmpF during a kinetic analysis of the process. The requirement for a concomitant lipid synthesis during the trimerization has been demonstrated by investigating the presence of a specific native epitope. The role of lipopolysaccharide during the stabilization of the conformation is discussed with regard to the various steps of assembly.

Cytotoxic T lymphocyte recognition of secreted HLA class I molecules.

The cytolytic responses of DBA/2 mice against syngeneic transfected P815 mastocytoma cells expressing either membrane-associated (HLA-Cw3) or -secreted hybrid (HLA-Cw3 x H-2 Q10b) molecules were compared. In spite of the absence of serologically detectable hybrid molecules on their plasma membrane, cells secreting these molecules elicited a CTL response similar to that of cells expressing the membrane associated HLA-Cw3 molecules, in terms of both MHC-restriction and peptide specificity. Together with the observation that syngeneic mice were capable of rejecting the injected secreting cells, these results imply that secreted HLA class I molecules can function as minor histocompatibility Ag and suggest that processing of both the membrane-bound and the -secreted forms of a protein may follow common or overlapping pathways.