Investigation de l'effet du peptide antimicrobien KSL-W sur les cellules souches de la pulpe dentaire : une perspective de traitement endodontique

En endodontie, les peptides antimicrobiens (AMP) pourraient résoudre les limitations potentielles liées à l'utilisation d'antibiotiques. L’objectif de cette étude était d’évaluer l’effet du KSL-W sur l’adhésion, la prolifération et la migration des cellules souches de la pulpe dentaire (DPSC). Méthodes : Les DPSC ont été cultivées en présence et en l'absence de KSL-W à différentes concentrations ou d’une combinaison de deux (ciprofloxacine et métronidazole ; DAP) ou trois (ciprofloxacine, métronidazole et minocycline ; TAP) antibiotiques. L'adhésion cellulaire a été évaluée à l’aide de coloration au cristal violet et d’observations microscopiques. La viabilité/l’activité métabolique (V/AM) des DPSC a été étudiée par un test MTT. L'effet de KSL-W sur la migration cellulaire / la guérison des blessures a été évaluée à l'aide du test de blessure de la culture dite ″scratch test″. Les données collectées ont été analysées par ANOVA. Une différence significative a été considérée à P ≤ 0.05. Résultats : Le KSL-W n’a pas d’effet inhibiteur sur l’adhésion des DPSC, comparativement au DAP et au TAP. Ces observations sont confirmées par nos analyses de viabilité/activité métaboliques (V/AM) des cellules. En effet, les résultats du MTT ont montré une V/AM plus adéquate en présence de KSL-W. À titre d’exemple, les cellules en présence de KSL-W à 10 et 50 µg/ml, montrent une V/AM comparable au contrôle (cellules non traitées). Il est important de noter que le KSL- W a favorisé la migration cellulaire après une blessure. Les DPSC ont pu migrer et recouvrir la blessure plus rapidement avec KSL- W qu’avec les antibiotiques. Conclusion : Comparativement aux antibiotiques, le KSL-W n’a pas d’effets négatifs sur l'adhésion et la V/AM. Ce peptide semble favoriser la migration cellulaire. Ces travaux suggèrent l’utilisation du KSL-W comme un agent antimicrobien pouvant être utilisé en endodontie

Efficacy and safety of tocilizumab in COVID-19 patients: a living systematic review and meta-analysis

ObjectivesCytokine release syndrome with elevated interleukin-6 (IL-6) levels is associated with multiorgan damage and death in severe coronavirus disease 2019 (COVID-19). Our objective was to perform a living systematic review of the literature concerning the efficacy and toxicity of the IL-6 receptor antagonist tocilizumab in COVID-19 patients. MethodsData sources were Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, Web of Science, Scopus up, preprint servers and Google up to October 8, 2020. Study eligibility criteria were randomized controlled trials (RCTs) and observational studies at low or moderate risk of bias. Participants were hospitalized COVID-19 patients. Interventions included tocilizumab versus placebo or standard of care. We pooled crude risk ratios (RRs) of RCTs and adjusted RRs from cohorts, separately. We evaluated inconsistency between studies with I2. We assessed the certainty of evidence using the GRADE approach. ResultsOf 1156 citations, 24 studies were eligible (five RCTs and 19 cohorts). Five RCTs at low risk of bias, with 1325 patients, examined the effect of tocilizumab on short-term mortality; pooled RR was 1.09 (95%CI 0.80–1.49, I2 = 0%). Four RCTs with 771 patients examined the effect of tocilizumab on risk of mechanical ventilation; pooled RR was 0.71 (95%CI 0.52–0.96, I2 = 0%), with a corresponding number needed to treat of 17 (95%CI 9–100). Among 18 cohorts at moderate risk of bias with 9850 patients, the pooled adjusted RR for mortality was 0.58 (95%CI 0.51–0.66, I2 = 2.5%). This association was observed over all degrees of COVID-19 severity. Data from the RCTs did not show a higher risk of infections or adverse events with tocilizumab: pooled RR 0.63 (95%CI 0.38–1.06, five RCTs) and 0.83 (95%CI 0.55–1.24, five RCTs), respectively. ConclusionsCumulative moderate-certainty evidence shows that tocilizumab reduces the risk of mechanical ventilation in hospitalized COVID-19 patients. While RCTs showed that tocilizumab did not reduce short-term mortality, low-certainty evidence from cohort studies suggests an association between tocilizumab and lower mortality. We did not observe a higher risk of infections or adverse events with tocilizumab use. This review will continuously evaluate the role of tocilizumab in COVID-19 treatment

Senolytics and senostatics as adjuvant tumour therapy

Cell senescence is a driver of ageing, frailty, age-associated disease and functional decline. In oncology, tumour cell senescence may contribute to the effect of adjuvant therapies, as it blocks tumour growth. However, this is frequently incomplete, and tumour cells that recover from senescence may gain a more stem-like state with increased proliferative potential. This might be exaggerated by the induction of senescence in the surrounding niche cells. Finally, senescence will spread through bystander effects, possibly overwhelming the capacity of the immune system to ablate senescent cells. This induces a persistent system-wide senescent cell accumulation, which we hypothesize is the cause for the premature frailty, multi-morbidity and increased mortality in cancer survivors. Senolytics, drugs that selectively kill senescent cells, have been developed recently and have been proposed as second-line adjuvant tumour therapy. Similarly, by blocking accelerated senescence following therapy, senolytics might prevent and potentially even revert premature frailty in cancer survivors. Adjuvant senostatic interventions, which suppress senescence-associated bystander signalling, might also have therapeutic potential. This becomes pertinent because treatments that are senostatic in vitro (e.g. dietary restriction mimetics) persistently reduce numbers of senescent cells in vivo, i.e. act as net senolytics in immunocompetent hosts

Rôle du transport endosomal dépendant du rétromère dans la formation des podosomes en réponse à l'activation de V-SRC

À mon arrivée dans le laboratoire, les travaux réalisés indiquaient que le trafic des endosomes de recyclage (ERs) vers le Golgi était régulé par les kinases de la famille Src (KFS) et contribuait au remodelage de l’actine induit par différents stress (E4orf4, staurosporine). Or les KFS coordonnent la dynamique de l’actine et le trafic membranaire, mais les mécanismes impliqués demeurent peu caractérisés. Des évidences récentes indiquaient aussi que le trafic endosomal contribuait à la transformation cellulaire induite par des formes oncogéniques des KFS, laquelle est associée à l’assemblage de structures invasives riches en actine (podosomes). En se basant sur ces données, notre hypothèse de recherche était que le transport des ERs vers le Golgi sous le contrôle du rétromère, un régulateur majeur des voies de transport rétrograde, pourrait contribuer à la formation des podosomes lors de la transformation cellulaire induite par v-Src. Les objectifs du travail présenté dans ce mémoire étaient de caractériser les changements précoces dans le trafic endosomal dépendant du rétromère suivant l’activation de v-Src et d’adresser leur contribution dans la formation des podosomes. Mes travaux ont tiré profit de l’utilisation d’un modèle permettant l’activation rapide d’un mutant thermosensible de v-Src dans des cellules épithéliales MDCK. J’ai ainsi pu observer dans ce modèle une polarisation précoce des ERs autour des podosomes en formation. Une augmentation dans le nombre et la morphologie des endosomes rétromère-dépendants (Vps26) a été mesurée et coïncidait avec un transport accru de cargos dépendants du rétromère vers le Golgi. Notamment, l’inhibition de Rab7, un régulateur du rétromère, interfère avec la formation des endosomes Vps26-positifs et des podosomes. En conclusion, mes résultats suggèrent que v-Src active les voies de transport dépendantes du rétromère pour mobiliser des protéines de signalisation et/ou des lipides bioactifs nécessaires au remodelage polarisé de l’actine et à la formation des structures invasives

Anti-degradative Total-Etch Adhesive to Preserve Bonded Interfaces

Background: Preserving resin composite bonded interfaces with teeth from biochemical degradation could increase their longevity. Objective: Investigate the effect of loading octenidine dihydrochloride drug-silica particles (OCT-DSPs) into a model total-etch adhesive (TE) on the physical integrity of resin-dentin interface, incubated in simulated human salivary esterase (SHSE). Methods: Miniature Short Rod specimens were made from resin-composite bonded to dentin using TE only, OCT-DSP-TE or C-DSP-TE (calcined particles without drug). Specimens were tested for fracture toughness (FT) and analyzed for fracture mode immediately or after 30-days and 180-days SHSE incubation. Results: OCT-DSPs or C-DSPs had no significant effect on FT vs TE at any time point. All groups showed a significant FT reduction after 180-days incubation. The fracture plane for all groups moved from resin to dentin after 180-days incubation. Conclusion: The addition of DSPs did not preserve the FT of the resin-dentin interface, suggesting that neither the particles nor the drug affects biostability.M.Sc

Redesigning the Door to Doctor (D2D) Process in Emergency Department: The Key to a Successful Patient-Centered Story

Lean management, when adopted in health care settings, will influence clinicians to find better ways for providing health care services to patients. In ED’s everyday processes, lean focuses on improving the ED process flow through facilitating communication among ED staff and eliminating any unnecessary steps (wastes) along the process. An observational cross-sectional study has been conducted at the Emergency Department (ED) of the American University of Beirut- Medical Center (AUBMC), to assess the extent upon which AUBMC-ED is lean. The time it takes the patient to be examined by an attending doctor, from the moment s/he hits the ED door, denoted as Door-to Doctor (D2D), was measured. A sample size (n) of 135 D2D timings was collected over a period of twenty nine days (October 28th till November 21st, and November 29th till December 2nd, 2013). Average D2D timing was found to be 25 minutes. The current process map of AUBMC-ED was also assessed and analyzed to identify any non-value added steps and obstacles that contributed to such D2D timings. These are increasing the crowding in ED and hindering the ED staff from performing their duties efficiently. These include: ED door being utilized by individuals not directly heading to ED, entrance of more than two relatives per patient in to the different ED units, security guards performing duties not inherent to their jobs such as greeting, and patients and/or relatives being unaware of steps to do after they are done with registration. The paper then proposes multiple feasible recommendations that would redesign the current process map of AUBMC-ED for it to become leaner. These recommendations can serve as a point of reference to promote lean thinking in EDs of other academic hospitals in Lebanon and the region

Bacterial DNA delays apoptosis of human neutrophils through TLR9.

<p>(<b>A</b>) Co-localisation of CpG DNA and TLR9. Neutrophils were incubated with Alexa Fluor 488-labeled CpG DNA and then stained with R-PE-conjugated anti-TLR9 eB72-1665 and 4′,6-diamidino-2-phenylindole (DAPI). Images were captured using a Leica DMRI fluorescence microscope and are representative of 3 neutrophil preparations from different blood donors. Scale bar: 10 µm. (<b>B</b>) Concentration-dependence of the effects of CpG DNA on neutrophil apoptosis. Neutrophils (5×10⁶ cells/ml) were cultured for 24 h with increasing concentrations of CpG DNA and viability (propidium iodide staining), mitochondrial transmembrane potential (ΔΨ_m) (CMXRos staining) and apoptosis (annexin-V-FITC binding and nuclear DNA content) were assessed. (<b>C–F</b>) Telomere-derived iODN inhibits the actions of CpG DNA. Neutrophils were incubated for 10 min with iODN (0.6 or 2.4 µM) or ctlr-ODN (2.4 µM) and then challenged with CpG DNA (1.6 µg/ml) for 24 h. (<b>G, H</b>) K12-DNA delays neutrophil apoptosis. Neutrophils were cultured for 24 h with LPS-free K-12-DNA (1.6 µg/ml) or ultra pure LPS (1 µg/ml) and viability (<b>G</b>) and annexin-V-FITC binding (<b>H</b>) were assessed. Data are means ±SEM (n = 3–5). *P<0.05; **P<0.01; ***P<0.001 vs. untreated.^#P<0.05; ^##P<0.01.</p

CpG DNA induces Mcl-1 gene transcription.

<p>Neutrophils (10⁷ cells/ml) ± CpG DNA (1.6 µg/ml) were incubated for the indicated times. Mcl-1 gene expression was assessed by quantitative real-time PCR and was normalized using 18s rRNA as an endogenous control. Data are means ±SEM (n = 3–5). *P<0.05 vs. untreated at time 0.</p

Blastic plasmacytoid dendritic cell neoplasm: challenges in diagnosis and treatment with potential of venetoclax as an alternative to vincristine in high-risk patients—a case report

Abstract Background Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and challenging cancer for diagnosis and treatment. Accurate diagnosis plays a crucial role guiding appropriate treatment, typically involving high-intensity lymphoblastic leukemia regimens which typically include vincristine. However, the use of vincristine may be particularly limited in patients with pre-existing neuropathy or individuals at high risk of developing it. Here, we present a case of BPDCN that was initially diagnosed as marginal zone lymphoma (MZL) and subsequently as non-specific T-cell lymphoma, thus highlights the importance of accurate diagnosis and modified treatment. Case presentation A 49-year-old Arab man with a medical history of diabetes, peripheral neuropathy, hypertension, and depression presented with widespread, painless multiple skin lesions. After undergoing a biopsy at another institution, the patient was initially diagnosed with MZL, and received two cycles of bendamustine and rituximab. However, the disease relapsed and was later diagnosed with non-specific T-cell lymphoma, which proved refractory to a single cycle of CHOP chemotherapy. The patient was subsequently referred to our centre, where a comprehensive evaluation revealed BPDCN with a unique finding on bone marrow exam: signet ring plasmacytoid dendritic cells. Due to the patient's pre-existing neuropathy and previous treatment, we administered the Hyper-CVAD regimen with a 50% reduction in vincristine dosage, which resulted in an excellent response. During the second part of cycle one, when new skin lesions started appearing, venetoclax was added to the treatment regimen. Subsequently, we discontinued vincristine due to worsening neuropathic pain and neuropathy-related weakness. Venetoclax was continued in cycle two and led to a complete response. The patient achieved a disease-free state for the first time in disease course, maintaining it for a period of over six weeks before experiencing a relapse. Conclusions Accurate diagnosis is crucial for guiding appropriate treatment. Our case highlights the challenges associated with diagnosis and treatment, as well as the potential of venetoclax as an alternative to vincristine, particularly in patients with pre-existing neuropathy or those at a high risk of developing it. Further research is needed to evaluate the effectiveness of BCL2 inhibitors as a replacement for essential drugs and its potential as a bridging therapy until patients can undergo a stem cell transplant