Médecine d’urgence : ce qui a changé en 2022 [Emergency medicine: what's new in 2022]

Emergency medicine is facing many challenges, particularly related to the consequences of the pandemic on the pressure of patient flows and the lack of human resources. More than ever, our discipline seeks to offer our patients quality care based on several recent studies, of which the following is a section: a) Gender effect in the administration of tranexamic acid; b) External validation of the Canadian Syncope Risk Score; c) Role of neuro-imaging in psychiatric decompensation; d) Choice of analgesia in renal colic; e) Use of carotid ultrasound for pulse control in cardiac arrest and f) The safetyness of performing simple sutures in non-sterile conditions

Prognostic value of donor cytotoxic T-lymphocyte precursor frequencies for acute graft-versus-host disease in hematopoietic stem cell transplantation from HLA-matched siblings: A single center experience in a cohort of 92 patients

We investigated the prognostic value of cytotoxic T-lymphocyte precursor frequencies (CTL-p-f) for the development of graft-versus-host disease (GvHD) in a cohort of 92 recipients of a hematopoietic stem cell transplantation from HLA-matched sibling donors. CTL-p-f and clinical variables were correlated with acute GvHD and chronic GvHD in univariate and multivariate analyses. CTL-p-f resulted an independent risk factor for severe acute GvHD. Moreover, a trend towards a correlation between CTL-p-f and chronic GvHD was observed. In summary CTL-p-f may be considered as a functional assay useful for identifying patients at high risk of severe GVHD. ©2006 Ferrata Storti Foundation

Cytotoxic T lymphocyte precursor frequency as a predictor of acute graft-versus-host disease in bone marrow transplantation from HLA-identical siblings

The measurement of precursor frequencies of donor anti-recipient cytotoxic T lymphocytes (CTL-p) has been shown to predict the incidence and the severity of acute graft-versus-host disease (aGVHD) in unrelated donor bone marrow transplantation (BMT). In HLA-identical sibling BMT, where aGVHD is most likely caused by minor histocompatibility antigen mismatches, this assay did not appear to be sensitive enough to provide similar predictive information. In this study, the CTL-p frequencies and the incidence and severity of aGVHD in 51 onco-hematological patients transplanted from HLA-identical siblings were compared. Sibling donors were selected on the basis of HLA identity using serological typing for HLA-A, B, C antigens, whereas HLA-DRB was tested by molecular analysis. Sibling identity was also confirmed by DNA heteroduplex analyses. Fifteen out of 21 (71%) patients with high precursor frequency (>1:100 x 103) and 12 out of 30 (40%) with low precursor frequency (<1:100 x 103) experienced clinically significant (II-IV) aGVHD. A significant correlation (P = 0.04) between CTL-p frequency and severe aGVHD was demonstrated. Moreover there was a positive trend for a high frequency response according to an increasing grade of aGVHD, which was statistically significant (P = 0.04). In our experience the CTL-p assay is a helpful predictive test for aGVHD in HLA-identical sibling BMT, indicating high risk patients possibly requiring additional prophylaxis

A comparison of cytotoxic T lymphocyte precursor frequencies in responder/stimulator pairs with increasing degrees of mismatch

Limiting dilution assays of helper or cytotoxic T cell precursor (HTL-p and CTL-p) frequencies have been developed to measure, with high sensitivity and specificity, donor/recipient alloreactivity before bone marrow transplantation (BMT). Most studies demonstrated a significant correlation between the frequency of donor host-specific CTL-p before transplant and the incidence of severe (≥ grade II) acute graft-versus-host disease (aGvHD) in unrelated donor BMT. Recently we demonstrated that the CTL-p assay was sensitive enough to provide similar predictive information also in HLA-identical sibling BMT. In the present study, the CTL-p frequencies were compared in four groups of responder/stimulator pairs with different degree of mismatch: (1) monozygotic twins (MZ) (n=7), (2) HLA-identical sibling pairs (SIB) (n=67), (3) HLA-matched unrelated pairs (HLA-A, B serologically and HLA-DRBI allele-matched) (MUP) (n=59), (4) 2-4 antigen HLA-mismatched pairs (MM) (n=27). Logistic regression analysis showed that as mismatch increased, the probability of a high (>1:100.000) CTL-p frequency (HF) significantly increased. Then, MUP group was divided in two subgroups: (3a) well-matched pairs (WM) (n=20): matched for HLA-DRB3, B4, B5 alleles and, by DNA heteroduplex analysis, for HLA-A, B genes; (3b) matched pairs (M) (n=39): with either a single HLA-A, B mismatch as revealed by DNA heteroduplex analysis, or a single mismatch in HLA-DRB3, B4, B5 alleles. The CTL-p frequencies were analysed again in the five groups, re-using a logistic regression model. The probability of a HF response was significantly higher in the M than in SIB group. Otherwise, WM and SIB groups had the same probability of a HF response. The probability of a HF response in the M group was significantly higher than in WM group, and lower, though not significantly, than in MM group. The results confirmed not only the power of CTL-p assay in the identification of functionally significant polymorphisms, but also in measuring the degree of mismatch in responder/stimulator pairs. They also showed that when unrelated pairs were more closely matched, CTL-p frequencies approached those of SIB. In conclusion, the CTL-p assay may be an important "in vitro" tool in BMT helping also to predict alloreactivity due to minor histocompatibility antigen differences, which still remain difficult to define despite the improvements in unrelated donor matching. © 2001 Blackwell Science Ltd,

Sustained calcium signalling and caspase-3 activation involve NMDA receptors in thymocytes in contact with dendritic cells

L-glutamate, the major excitatory neurotransmitter, also has a role in non-neuronal tissues and modulates immune responses. Whether NMDA receptor (NMDAR) signalling is involved in T-cell development is unknown. In this study, we show that mouse thymocytes expressed an array of glutamate receptors, including NMDARs subunits. Sustained calcium (Ca2+) signals and caspase-3 activation in thymocytes were induced by interaction with antigen-pulsed dendritic cells (DCs) and were inhibited by NMDAR antagonists MK801 and memantine. NMDARs were transiently activated, triggered the sustained Ca2+ signal and were corecruited with the PDZ-domain adaptor postsynaptic density (PSD)-95 to thymocyte-DC contact zones. Although T-cell receptor (TCR) activation was sufficient for relocalization of NMDAR and PSD-95 at the contact zone, NMDAR could be activated only in a synaptic context. In these T-DC contacts, thymocyte activation occurred in the absence of exogenous glutamate, indicating that DCs could be a physiological source of glutamate. DCs expressed glutamate, glutamate-specific vesicular glutamate transporters and were capable of fast glutamate release through a Ca2+-dependent mechanism. We suggest that glutamate released by DCs could elicit focal responses through NMDAR-signalling in T cells undergoing apoptosis. Thus, synapses between T and DCs could provide a functional platform for coupling TCR activation and NMDAR signalling, which might reflect on T-cell development and modulation of the immune response

Cavezzo, the first Italian meteorite recovered by the PRISMA fireball network. Orbit, trajectory, and strewn-field

International audienceTwo meteorite pieces have been recovered in Italy, near the town of Cavezzo (Modena), on 2020 January 4th. The associated fireball was observed on the evening of New Year's Day 2020 by eight all-sky cameras of the PRISMA fireball network, a partner of FRIPON. The computed trajectory had an inclination angle of approximately 68° and a velocity at infinity of 12.8 km s-1. Together with the relatively low terminal height, estimated as 21.5 km, those values were indicating the significant possibility of a meteorite dropping event, as additionally confirmed by the non-zero residual total mass. The strewn-field was computed taking into account the presence of two bright light flashes, revealing that the meteoroid had been very likely subject to fragmentation. Three days after the event, two samples, weighing 3.1 and 52.2 g, were collected as a result of a dedicated field search and thanks to the involvement of the local people. The two pieces were immediately recognized as freshly fallen fragments of meteorite. The computed orbital elements, compared with the ones of known Near-Earth Asteroids from the NEODyS database, are compatible with one asteroid only; 2013 VC10. The estimated original mass of the meteoroid, 3.5 kg, and size, approximately 13 cm, is so far the smallest among the current 35 cases in which meteorites were recovered from precise strewn-field computation thanks to observational data. This result demonstrates the effectiveness of accurate processing of fireball network data even on challenging events generated by small size meteoroids