Direct contact of platelets and their released products exert different effects on human dendritic cell maturation

<p>Abstract</p> <p>Background</p> <p>Dendritic cells (DCs) are antigen presenting cells capable of inducing innate and adaptive immune responses. According to the stimulus and their maturation state, DCs induce immunogenic or tolerogenic responses. Platelets (PLTs), which are involved in haemostasis and inflammation, can also interact with DCs. In this study, we examined the effect of PLTs on DC maturation <it>in vitro</it>. Human monocyte-derived DCs were co-cultured for 2 days with homologous PLTs either in the same well or in 0.4 μm-pore size filter-separated compartments.</p> <p>Results</p> <p>Confocal microscopy showed the attachment of PLTs to DC membranes. The DC receptor involved in this interactions was found to be CD162. In addition, we observed that DCs co-cultured with PLTs in filter-separated compartments acquired a mature phenotype (high CD80, CD86, and intermediate CD83 expression; IL-12(p70) production; efficient stimulation of autologous CD4+ T cell proliferation), while DCs co-cultured with PLTs in the same compartment did not undergo phenotypic maturation, did not secrete IL-12(p70) or IL-1β, but instead induced moderate Th2-polarized T cell proliferation.</p> <p>Conclusion</p> <p>These data indicate that (i) PLTs secrete a soluble DC-activating factor that was demonstrated not to be soluble CD40-Ligand (CD154; as could have been expected from <it>in vivo </it>and previous <it>in vitro </it>work) but to be nucleotide, and (ii) that cell-to-cell contact did not induce DC maturation, possibly because nucleotide release by PLTs was prevented by direct contact with DCs. This work demonstrates that PLTs are active elements of the immune system that might play a role in balancing the ability of DCs to polarize T cell responses, therefore making them critical factors in transfusion processes.</p

Release of immune modulation factors from platelet concentrates during storage after photochemical pathogen inactivation treatment

Background: Blood platelets (PLTs) are critical for hemostasis, and they contain biologically active constituents with the potential to modulate inflammatory responses. This study examined the effects of photochemical pathogen inactivation treatment (PCT) on the release of cytokines and/or chemokines from PLT components. Study desing and methods: Double-dose apheresis PLT components were suspended in plasma-PLT additive solution mixtures and divided into paired therapeutic units. One unit served as an untreated control and the other unit was treated with PCT. PLT concentrations, pH, and levels of cytokines and/or chemokines (CD62p, platelet-derived growth factor-AB, interleukin [IL]-8, soluble CD40 ligand [sCD40L], IL-1 beta, and tumor necrosis factor alpha) were measured during 7 days of storage in PLT component supernatants and PLT lysates. Results: PLT content, pH, and cytokine and/or chemokine content and release from PLT component prepared with PCT were not different (p > 0.05) from paired control components during storage. Levels of sCD40L, however, increased significantly during storage while decreasing in parallel within PLT lysates, although no differences were detected between paired PCT and control PLT component. Conclusion: PCT did not increase the release or secretion of PLT chemokines and/or cytokines over a 7-day period compared to conventional PLT component

A Computerized Prediction Model of Hazardous Inflammatory Platelet Transfusion Outcomes

International audiencePlatelet component (PC) transfusion leads occasionally to inflammatory hazards. Certain BRMs that are secreted by the platelets themselves during storage may have some responsibility. First, we identified non-stochastic arrangements of platelet-secreted BRMs in platelet components that led to acute transfusion reactions (ATRs). These data provide formal clinical evidence that platelets generate secretion profiles under both sterile activation and pathological conditions. We next aimed to predict the risk of hazardous outcomes by establishing statistical models based on the associations of BRMs within the incriminated platelet components and using decision trees. We investigated a large (n = 65) series of ATRs after platelet component transfusions reported through a very homogenous system at one university hospital. Herein, we used a combination of clinical observations, ex vivo and in vitro investigations, and mathematical modeling systems. We calculated the statistical association of a large variety (n = 17) of cytokines, chemokines, and physiologically likely factors with acute inflammatory potential in patients presenting with severe hazards. We then generated an accident prediction model that proved to be dependent on the level (amount) of a given cytokine-like platelet product within the indicated component, e.g., soluble CD40-ligand (>289.5 pg/109 platelets), or the presence of another secreted factor (IL-13, >0). We further modeled the risk of the patient presenting either a febrile non-hemolytic transfusion reaction or an atypical allergic transfusion reaction, depending on the amount of the chemokine MIP-1α (20.4 pg/109 platelets, respectively). This allows the modeling of a policy of risk prevention for severe inflammatory outcomes in PC transfusion

Har bakterieidentifikasjon og resistensbestemmelse innvirkning på valg av antibiotikaregime ved bakteriemi? : en studie gjort ved Universitetssykehuset i Nord- Norge

Bakgrunn: Antibiotikaresistens er i dag blitt et signifikant problem på grunn av vårt misbruk – både overforbruk, underforbruk, feilbruk, manglende compliance, inadekvat dosering og ikke minst en likegyldighet til bruk. For alvorlige infeksjonssykdommer som sepsis kan dette gi dramatiske konsekvenser, da man er avhengig av effektive terapimidler da sykdommen er forbundet med høy morbiditet og mortalitet. Selv om Norge enda er et av de landene hvor resistensproblemet er minst så er det viktig at det tas på alvor, og at terapi følger gitte retningslinjer - blant annet ved sepsis hvor en initial bredspektret empirisk terapi raskest mulig bør endres til mer smalspektret terapi for å redusere risikoen for resistensutvikling. Formål: Formålet med denne studien var å undersøke om diagnostisk informasjon i form av mikrobiologisk bakterieidentifikasjon og resistensbestemmelse førte til endringer av bredspektret empirisk terapi ved bakteriemi. Karakterisering av endringer gjort og behandlingsregimer, og vurdere disse i forhold til gitte retningslinjer utarbeidet ved UNN i 2005 var også et mål med studien. Studien ble utført ved Avdeling for Mikrobiologi og Smittevern ved UNN, og sammenlignet med tilsvarende studie utført ved UNN i 2005 og ved St. Olavs Hospital i 2003. Metode: Studien er en deskriptiv observasjonsstudie basert på retrospektive data. Studiepopulasjonen var pasienter innlagt på UNN og med positive blodkulturer i 2006. Pasientjournaler og mikrobiologiske arbeidsskjemaer ble gjennomgått, og det ble registrert antibiotikabehandling og mikrobiologiske besvarelser for gitte registreringsperioder. Resultater: Av 276 episoder med reell bakteriemi ble det registrert endringer i terapiregimene i 34,1 % av besvarte episoder etter mikroskopifunn, 36,2 % etter preliminær resistensbestemmelse og 12,0 % etter definitiv resistensbestemmelse. Ved mistenkt bakteriemi var monoterapi med cefalosporiner eller kombinasjonsterapi med penicilliner og aminoglykosider mest fremtredende. Etter at mikrobiologiske data forelå bestod behandlingen av episoder med gram negative bakterier i hovedsak av monoterapi med cefalosporiner eller kombinasjonsterapi med enten penicilliner og aminoglykosider eller cefalosporiner og aminoglykosider. Behandlingen av episoder med gram positive bakterier bestod i hovedsak av monoterapi med penicilliner eller kombinasjonsterapi med penicilliner og aminoglykosider. Konklusjon: Resultatene tyder på at mikrobiologiske data hadde innvirkning på valg av antibiotikaregime ved bakteriemi. Det ble benyttet empirisk terapi anbefalt i antibiotikaveilederen i større grad ved UNN i 2006 enn ved UNN i 2002 og St. Olavs Hospital i 2002. Andelen monoterapi økte ved UNN fra 2002 til 2006. Resultatene av studien gir inntrykk av at terapien endret seg i henhold til bakterieidentifikasjon og resistensbestemmelse

Study of the Early Effects of Chitosan Nanoparticles with Glutathione in Rats with Osteoarthrosis

Due to cartilage’s limited capacity for regeneration, numerous studies have been conducted to find new drugs that modify osteoarthrosis’s progression. Some evidence showed the capability of chitosan nanoparticles with glutathione (Np-GSH) to regulate the oxide-redox status in vitro in human chondrocytes. This work aimed to evaluate the capacity of Np-GSH in vivo, using Wistar rats with induced surgical osteoarthritis. Radiographic, biochemical (GSH and TBARS quantification), histopathological, and immunohistochemical (Col-2 and MMP-13) analyses were performed to evaluate the progress of the osteoarthritic lesions after the administration of a single dose of Np-GSH. According to the results obtained, the GSH contained in the NPs could be vectored to chondrocytes and used by the cell to modulate the oxidative state reduction, decreasing the production of ROS and free radicals induced by agents oxidizing xenobiotics, increasing GSH levels, as well as the activity of GPx, and decreasing lipid peroxidation. These results are significant since the synthesis of GSH develops exclusively in the cell cytoplasm, and its quantity under an oxidation–reduction imbalance may be defective. Therefore, the results allow us to consider these nanostructures as a helpful study tool to reduce the damage associated with oxidative stress in various diseases such as osteoarthritis

A flow cytometry technique to study intracellular signals NF-κB and STAT3 in peripheral blood mononuclear cells-2

<p><b>Copyright information:</b></p><p>Taken from "A flow cytometry technique to study intracellular signals NF-κB and STAT3 in peripheral blood mononuclear cells"</p><p>http://www.biomedcentral.com/1471-2199/8/64</p><p>BMC Molecular Biology 2007;8():64-64.</p><p>Published online 31 Jul 2007</p><p>PMCID:PMC1949834.</p><p></p>) activation (versus untreated) from B-cells, T-lymphocytes and monocytes/macrophages. PBMCs were stimulated for the appropriate time and concentration of sCD40L (A) and IL10 (B) (as identified previously). The graphs represent the difference in percentage of phosphorylated nuclear factor between stimulated and untreated cells. Statistical significance (wilcoxon paired test; p < 0.05) was represented by an asterisk (*). Data represented the mean (± SD) of seven experiments

Stratégies de comptage par analyse d'image de l'endothélium des cornées conservées en organoculture : détection de contour versus pointage du centre . Counting strategies for endothelial assessment of organ cultured corneas using image analysis: comparison of border versus center method

International audienceAim To compare two different cell count strategies, border and center methods for endothelial assessment during corneal storage. Material and Methods Seven observers determined the endothelial cell density (ECD), coefficient of variation (CV) of cell area, and percentage hexagonality of 30 organ cultured corneas by the border (contour detection and manual retouch) and center method (indicating cell centers) using Sambacornea analyser. Interobserver variability for ECD and agreement between the two methods was determined. The accuracy of the center method was verified by counting on ten standard photolithographic mosaics (called keratotest) by border (reference method) and center methods, first as fast and next as precise as possible (fast and slow modes respectively) and the time noted. Data between border and center methods was compared using nonparametric paired tests. Results For stored corneas, interobserver variability was ±9.6% (95%CI [6.5-12.7]) for border method and ±9.3% (95%CI[6.3-12.3]) for center method. ECD [mean±SD (range), median] was [2948±565 (1644-3878), 3081] and [2961±568 (1736-3914), 3037] respectively and showed excellent correlation (Pearson coefficient r=0.998, p<0.001). The center method underestimated the CV by a mean 9.5%95%CI [8.3-10.7] and overestimated the hexagonality by a mean 2.5% (95%CI [1.4-3.7])(p<0.001 for both). Precision of indication of cell center influenced only the CV (mean for slow and fast modes being 3.6±0.7% and 7.4±1.3% respectively, p<0.001) but was more time consuming (p=0.005). Discussion The center method gives accurate and reproducible measurement of ECD and is comparable to the border method (reference). However, morphometric evaluation is not fully reliable. Conclusion Given that center method is easier to use in poor quality images, we recommend its use only for these cases

Pearson correlation matrix of 16 soluble factors in 65 ATRs supernatants.

<p>The bold values were different from 0 at a significance level of α = 0.05.</p