[The contribution of teleconsultation and isolation of symptomatic cases in control of the COVID-19 outbreak a military base]. / Apport de la téléconsultation et de l'isolement des cas symptomatiques dans la maîtrise de l'épidémie COVID-19 au sein d'une base militaire.

BACKGROUND: The first wave of COVID-19 swept over France during the first quarter of 2020, leading to saturation of the health care system. We wished to study, in a French military medical unit assisting one of the country's largest armed forces populations, the impact of teleconsultation and the systematic isolation of all possible, probable and confirmed cases of COVID-19. METHODS: This is a retrospective study carried out from March 9 to May 31, 2020 on the basis of our activity register. The variables collected included type of medical consultation procedure, occupational status, classification of cases and date of onset of first symptoms. We have paralleled our activity with that of SOS Médecins and the emergency departments of the Île-de-France region. RESULTS/DISCUSSION: During this period, 1719 episodes of care (teleconsultations or physical consultations) were recorded, of which 91% (n=1561) were linked to COVID-19. We identified 598 "suspected" (possible and probable) and confirmed cases. "Isolated" teleconsultations (not followed by a face-to-face medical consultation, sample taking or necessitating the dispatch of prompt assistance) represented 86% of episodes of care (n=1482). Comparison of our activity and the number of new cases with the databases of SOS Médecins and the Île-de-France emergency services suggests that our isolation strategy was timely and effective. CONCLUSION: The contribution of teleconsultation was substantial and reassuring. Teleconsultation makes it possible to absorb a large volume of patients, is easy to implement, and entails no nosocomial risk. Isolation of infected patients should be a priority during an outbreak. Once it has become a priority to rapidly bring an epidemic under control, this attitude must be extended to all symptomatic patients.

Inheritance of skeletal deformities in gilthead seabream (Sparus aurata) - lack of operculum, lordosis, vertebral fusion and LSK complex.

Morphological abnormalities in farmed gilthead seabream (Sparus aurata) are a major problem as it entails significant economic losses. In this study, 3 large scale experiments under different conditions of spawning, offspring handling and breeders phenotype were performed to analyze the inheritance of 4 types of deformities in this species: lack of operculum, lordosis, vertebral fusion, which are 3 of the most important skeletal deformities, and LSK, which is a consecutive repetition of lordosis/scoliosis/kyphosis. In Exp. [1] (mass spawning and fingerling sorting), 900 fish were analyzed at 509 d post-hatching: 846 fish that had been on-grown in a farm and 54 LSK-deformed fish that had been reared separately after being selected during the fingerling sorting process. A total of 89 families were represented. A statistically significant association between 5 of these families (from 6 breeders) and LSK-deformed fish was found. In Exp. [2] (mass spawning and no fingerling sorting), 810 fish were analyzed at 2 ages: 179 and 689 d post-hatching. Significant relationships between 2 of the breeders and 2 of the families with the lack of operculum prevalence of their descendants were found at 689 d but not at 179 d. Heritabilities: 0.09 ± 0.09 at 179 d and 0.17 ± 0.08 at 689 d. Column deformities prevalence was low and no association with family was observed. Family relationships were determined by microsatellites multiplex PCR in both experiments. In Exp. [3] (designed mating), sires suffering from lordosis or lack of operculum or vertebral fusion deformities were mated with non-deformed dams and a mass-spawning mating was considered as a control. After analyzing 11,503 offspring at 159 d post-hatching, a significant relationship between each deformity prevalence and the mating of breeders suffering from the same deformity was observed. In addition, a significant prevalence of lack of operculum in offspring from lordotic matings was observed. Heritabilities ranged from 0.34 to 0.46 for the 3 deformities. The results of the present study suggest that these deformities have a genetic origin. They also suggest that the sorting process is not recommended and that producers should consider these deformities in genetic breeding programs to significantly improve their fish morphological quality and to minimize farmed fish deformities incidence.

A rare case of paraplegia complicating a lumbar epidural infiltration.

OBJECTIVE: We report the case of a patient who developed paraplegia following a low lumbar epidural steroid injection. Alternative approaches to (or alternative means of) performing transforaminal injections should be considered, in order to avoid devastating neurological complications. CASE REPORT: A 54-year-old man (who had undergone surgery 14 years earlier to cure an L5-S1 slipped disc with right S1 radiculopathy) presented with low back pain (which had begun 6 weeks previously) and left S1 radiculopathy. During a second infiltration of prednisolone acetate, the patient reported feeling a heat sensation in his legs and concomitantly developed facial flushing. Immediately after the injection, the patient developed complete, flaccid T7 ASIA A motor and sensory paraplegia. Three days later, T2 magnetic resonance imaging (MRI) of the spine revealed a spontaneous hypersignal in the conus medullaris and from T6 to T9, suggesting medullary ischemia. Recovery has been slow; after 4 months of treatment in a physical and rehabilitation medicine department, urinary and sensory disorders are still present (T7 ASIA D paraplegia). The patient can walk 200 m unaided. Three months later, the MRI data had not changed. DISCUSSION: This is a rare case report of paraplegia following low lumbar epidural infiltration via an interlaminar route. The mechanism is not clear. Most of authors suggest that the pathophysiological basis of this type of complication is ischemia caused by accidental interruption of the medullary blood supply. Direct damage to a medullary artery, arterial spasm or corticosteroid-induced occlusion due to undetected intra-arterial injection could result in medullary infarction. This serious incident should prompt us to consider how to avoid further problems in the future. It also raises the issue of providing patients with information on the risks inherent in this type of procedure. CONCLUSION: Despite the rarity of this complication, patients should be made aware of its potential occurrence. In the case reported here, the functional prognosis is uncertain.

Potential interaction between annexin VI and a 56-kDa protein kinase in T cells.

Annexins belong to a large family of calcium-dependent phospholipid binding proteins known to undergo post-translational modifications such as phosphorylation. Physiological function of each annexin is still unclear since they may participate in signal transduction. We have tested the presence of annexins in a T cell line (Jurkat) and studied their phosphorylation by protein tyrosine kinases of the src family. Among annexins I, II, V and VI found in Jurkat cells, annexin VI was shown to be phosphorylated in vitro by p56lck and annexins I and II by p60src. We could not detect the phosphorylation of A-VI in vivo, even after cell stimulation. However, a 56-kDa phosphoprotein was found to be associated with A-VI after T cell activation. This 56-kDa protein shares some characteristics with p56lck.

Contribution of p56lck to the upregulation of cytokine production and T cell proliferation by IL-2 in human CD3-stimulated T cell clones.

Interaction of the interleukin 2 receptor (IL-2R) beta chain with the lymphocyte-specific protein tyrosine kinase (PTK), p56lck, has led to the speculation that p56lck participates in growth signal transduction. Although activation of T cells with interleukin 2 (IL-2) results in the activation of p56lck, accumulating data support the notion that Lck does not play an essential role in mitogenic signal delivery from the IL-2R. Since this src-related PTK has been shown to enhance TCR/CD3-mediated T cell responsiveness, here we investigated whether activation of Lck by IL-2 could contribute to enhance TCR/CD3-mediated T cell functions. This was achieved by using human CD4(+)-cloned T cells and comparing the effects of IL-2 on p56lck kinase activation and cytokine production. Results show that p56lck kinase activity increased as early as 1 min, reached a maximum within 5 min and decreased within 60 min after IL-2 stimulation. Such treatment with IL-2 also resulted in enhancing T cell responsiveness to CD3+PMA stimulation, as assessed by IL-2 and IFN-gamma secretion and by T cell proliferation. This increase of T cell functions was correlated with IL-2-induced p56lck activation in both dose-response and time-course experiments. Taken together these results strongly suggest that activation of Lck by IL-2 may play a role in regulating CD3-mediated T cell functions.

Contribution of tyrosine kinases to the selective orientation of human CD4+ bifunctional cloned T cells toward proliferation or cytolytic function.

We show that T cell activation of human CD4+ cloned T cells through the CD2 molecule can induce either autocrine proliferation or cytolysis, depending on the pair of anti-CD2 mAbs used for stimulation, that is, D66/T11(1) or GT2/T11(1), respectively. As the earliest biochemical event after CD2 stimulation is likely the induction of tyrosine phosphorylation of various proteins, we investigated whether differential activation of protein tyrosine kinases (PTKs) could contribute to the selective induction of each function. Results show that herbimycin A, a potent PTK inhibitor, markedly decreased the induction of both proliferation and cytolysis. This implies a regulatory role for tyrosine phosphorylation in the induction of each function by CD2. However, that PTKs are differentially activated upon induction of proliferation by D66/T11(1) or cytotoxic function by GT2/T11(1) emanated from two different approaches. First, immunoblotting total cellular extracts with an anti-phosphotyrosine mAb showed different patterns of tyrosine phosphorylation depending on the pair of CD2 mAbs used for stimulation. Second, a differential activation of p56lck, a src-related PTK, was observed after stimulation with D66/T11, and GT2/T11(1). Although induction of proliferation by D66/T11(1) was correlated with increased Lck activity, this was not observed when cells were triggered to lyse by GT2/T11(1). Thus, by providing striking correlative evidences linking differences in PTK activation with induction of different functions in bifunctional cloned T cells, our results strongly suggest that PTKs may contribute to the selective orientation of T cell functions at a single-cell level.

P56lck A lymphocyte specific protein tyrosine kinase: activation, regulation and signal transduction.

p56lck, a src family protein tyrosine kinase interacts with several T cell receptors, like: CD4, CD8, CD2 and the beta-chain of the IL2, thereby receptors devoid of kinase activity may transduce signals via tyr phosphorylation. Tyr 192 and ser 194, located in the SH2 domain of p56lck is phosphorylated upon CD3 triggering, which can change interactions of tyr-P proteins with this SH2 domain. Upon activation through the CD2 or the CD45 receptors the kinase activity of p56lck is temporarily increased. By immunofluorescent and confocal microscopy we observed that a significant proportion of p56lck and CD2 receptors are localized in endosomal vesicles after stimulation. By Western blot we showed a parallel recruitment of the PTK p70-ZAP in this vesicles. The role of p56lck away from the plasma membrane localized in vesicles is under study.

LFA-1-mediated antigen-independent T cell adhesion is regulated by CD4 and p56lck tyrosine kinase.

We examined the role of CD4 and p56lck in the regulation of LFA-1-dependent T cell adhesion to B cells and to fibroblasts expressing ICAM-1 and HLA-DR by using various transfectant constructions. Although CD4 transfection in CD4low HUT78 T cell lines did not significantly modify their maximal binding to B cells and fibroblasts, it made the LFA-1-dependent adhesion sensitive to inhibition by anti-CD4 Ab, HIV-1 (env) gp 160, and a 12-mer peptide encompassing the 35-46 sequence of the beta 1 domain of the MHC class II molecule. CD4low HUT78 T cell adhesion to B cells was stable over 60 min, whereas expression of CD4 led to a transient adhesion. In addition, adhesion of CD4+ T cells to MHC class II- B cells was also stable. The CD4-dependent alteration of adhesion required the association of CD4 with p56lck because expression of mutant forms of CD4 unable to bind p56lck resulted in a lack of CD4-dependent regulation of adhesion. Herbimycin A, an inhibitor of tyrosine kinase activity, reversed the effect of CD4 transfection on adhesion. These results indicate that ligand binding to CD4 delivers a signal-inducing cell dissociation by activating p56lck tyrosine kinase. This regulatory pathway may provide a quick and reliable way for multiple and subsequent Ag-independent adhesion events of CD4+ T cells.

Anti-CD3 and phorbol ester induce distinct phosphorylated sites in the SH2 domain of p56lck.

P56lck is a protein tyrosine kinase of the Src family specifically expressed in T lymphocytes. Triggering of T cells with anti-CD3 or with phorbol 12-myristate 13-acetate (PMA) results in the appearance of slower migrating forms (shift) of p56lck. To investigate the phosphorylation sites on the shifted forms of p56lck and to assess the role of protein kinase C in this phosphorylation, Jurkat cells were treated with a selective inhibitor of this kinase (GF 109203X). This inhibitor completely reversed the shift induced by PMA but only partially reversed the one induced after triggering with anti-CD3. To analyze the shift further, p56lck was immunoprecipitated from in vivo labeled cells treated either with anti-CD3 or with PMA. Tryptic phosphopeptides were generated and analyzed by using a combination of thin layer chromatography, high reticulation polyacrylamide gel electrophoresis, reverse phase chromatography, and phosphopeptide sequencing. We identified serine 158 as a newly phosphorylated site after PMA treatment and tyrosine 192 and serine 194 in the major tryptic phosphopeptide obtained after anti-CD3 triggering. The three sites identified are located in the SH2 domain of p56lck; this suggests that their phosphorylation may regulate the interaction with other proteins or with other internal domains in p56lck.

Human immunodeficiency virus gp120 and derived peptides activate protein tyrosine kinase p56lck in human CD4 T lymphocytes.

Human immunodeficiency virus binds to CD4 T lymphocytes by interaction between its envelope glycoprotein gp120 and the CD4 molecule. The latter is non-covalently associated with a src-related tyrosine kinase, p56lck. CD4 cross-linking increases the activity of p56lck, leading to phosphorylation of several cellular substrates. We report here that gp160/120 increases both the autophosphorylation of p56lck and its enzymatic activity (reflected by phosphorylation of an exogenous substrate) in normal T cells and the HUT78 CD4+ T cell line. This effect was detectable 5 min after activation and persisted for 40 min in normal T cells. It did not require gp120 cross-linking and was associated with phosphorylation of tyrosine residue on several proteins, as shown by phosphotyrosine Western blot analysis. The pattern of proteins phosphorylated on tyrosine residues in response to gp120 activation was distinct from that induced by anti-CD4 antibodies. p56lck activation required its association with CD4, since p56lck activity was not modified in HUT78 T cell lines expressing a truncated or mutated form of CD4 unable to associate with p56lck. Peptides mimicking residues 418 to 434 and 449 to 464 of HIV-1 Bru gp120, regions known to participate in gp120 binding to CD4, also increased p56lck activity and triggered phosphorylation of similar substrates. Taken together, these results show that gp160/120 and derived peptides can transiently increase p56lck activity without the need for CD4 cross-linking. This activation led to a specific pattern of tyrosine phosphorylation on cellular proteins that may be of significance in the biological effects of the gp120/CD4 interaction, e.g. syncytium formation and inhibition of T cell activation.

Cost-utility analysis of early thrombolytic therapy.

167 patients suffering from acute myocardial infarction (AMI) were recruited from 12 cardiology centres and given thrombolytic treatment. Cost-utility analyses were performed and a cost-utility ratio was computed according to time of initiation of thrombolysis after the AMI and the location of the infarct. Early thrombolysis ( less than 3 hours) proved to cost about the same per QALY ($US3734 vs $US3577) as late thrombolysis ( greater than 3 hours), although posterior infarcts cost slightly more per QALY ($3433 vs $2996) than anterior infarcts. Quality of life coefficients for all patients after the AMI were judged to be about 40% less than before the AMI. Thus, in terms of resources consumed and patient well-being, time of treatment initiation or location of the infarct were less significant than the fact of having an AMI. In terms of quality of life, the best strategy is that which seeks to prevent AMI occurring.

Interaction of human immunodeficiency virus glycoprotein 160 with CD4 in Jurkat cells increases p56lck autophosphorylation and kinase activity.

The tyrosine protein kinase p56lck, specifically expressed in lymphoid cells, undergoes modifications of its autophosphorylation and kinase activity when these cells are triggered by mAbs to the T cell determinants. The kinase activity and the autophosphorylation of p56lck were analysed following triggering Jurkat cells with the human immunodeficiency virus (HIV) glycoprotein gp160 which interacts with CD4: both the autophosphorylation and the kinase activity are increased within 1-5 min following addition of gp160, this increase is maximum at 5 min and is followed by a gradual return to the basal level within 2 h. Similar to observations made with anti-CD4 mAbs the increase in kinase activity of p56lck is not associated with changes in the gel mobility nor is it associated with T cell activation. Triggering of T cells with a combination of anti-CD3 mAbs which activate T cells but not p56lck and gp160 greatly potentiated the increase of p56lck autophosphorylation and kinase activity.

Elevated level of p60c-src in virus-transformed murine megakaryocytic cell lines.

Megakaryocytic cell lines derived from mouse bone marrow cells transformed by the Myeloproliferative Leukemia Virus (MPLV) contain elevated levels of p60c-src. Northern blot analysis revealed the presence of a 4 kb normal sized c-src transcript only in MPLV-transformed megakaryocytic cell lines containing a high percentage of acetylcholinesterase positive cells (AChE+ greater than 10%), but not in MPLV-transformed erythroblastic or myeloblastic cell lines. The p60c-src protein was identified in lysates from in vivo labelled cells and in in vitro labelled membrane extracts by immunoblotting analysis and by immunoprecipitations with specific anti-src antibodies. In dimethylsulfoxide (DMSO) treated cells, the number of AChE+ cells increased together with p60c-src kinase activity indicating a possible correlation between p60c-src expression/activity and megakaryocytic differentiation.

Phosphorylation of p56lck by external ATP in intact cells.

Recent studies have suggested a role for extracellular ATP. In this report we show that extracellular labelled ATP crosses the plasma membrane of intact lymphoma cells and peripheral blood lymphocytes and phosphorylates p56lck a tyrosine protein kinase specific of lymphoid cells. Two other phosphoproteins of 92Kd and 35Kd become detectable on alkali treated gels. Phosphorylation occurs within minutes following addition of ATP. ATP, GTP, ADP and an ATP analog prevent phosphorylation but not AMP nor Pi; trypsinization of cells abolishes labelling. The possible involvement of P2 purinergic receptors is discussed.