O2 Level Controls Hematopoietic Circulating Progenitor Cells Differentiation into Endothelial or Smooth Muscle Cells

BACKGROUND:Recent studies showed that progenitor cells could differentiate into mature vascular cells. The main physiological factors implicated in cell differentiation are specific growth factors. We hypothesized that simply by varying the oxygen content, progenitor cells can be differentiated either in mature endothelial cells (ECs) or contractile smooth muscle cells (SMCs) while keeping exactly the same culture medium. METHODOLOGY/PRINCIPAL FINDINGS:Mononuclear cells were isolated by density gradient were cultivated under hypoxic (5% O2) or normoxic (21% O2) environment. Differentiated cells characterization was performed by confocal microscopy examination and flow cytometry analyses. The phenotype stability over a longer time period was also performed. The morphological examination of the confluent obtained cells after several weeks (between 2 and 4 weeks) showed two distinct morphologies: cobblestone shape in normoxia and a spindle like shape in hypoxia. The cell characterization showed that cobblestone cells were positive to ECs markers while spindle like shape cells were positive to contractile SMCs markers. Moreover, after several further amplification (until 3(rd) passage) in hypoxic or normoxic conditions of the previously differentiated SMC, immunofluorescence studies showed that more than 80% cells continued to express SMCs markers whatever the cell environmental culture conditions with a higher contractile markers expression compared to control (aorta SMCs) signature of phenotype stability. CONCLUSION/SIGNIFICANCE:We demonstrate in this paper that in vitro culture of peripheral blood mononuclear cells with specific angiogenic growth factors under hypoxic conditions leads to SMCs differentiation into a contractile phenotype, signature of their physiological state. Moreover after amplification, the differentiated SMC did not reverse and keep their contractile phenotype after the 3rd passage performed under hypoxic and normoxic conditions. These aspects are of the highest importance for tissue engineering strategies. These results highlight also the determinant role of the tissue environment in the differentiation process of vascular progenitor cells

Detection of codon 12 K- ras mutations in non-neoplastic mucosa from bronchial carina in patients with lung adenocarcinomas

K- ras activation by point mutation in codon 12 has been reported in lung adenocarcinomas in various models of experimental lung tumours induced by chemical carcinogens. The hypothesis of the presence of cells containing K- ras mutation in non neoplastic bronchial carina, the main site of impaction of airborne contaminants, was investigated by evaluating concurrent lung tumour and non-neoplastic proximal bronchial carinae from 19 patients with lung adenocarcinomas. The restriction fragment length polymorphism enriched PCR method used can detect one mutant allele among 103normal alleles. A mutation was detected in 42% of lung adenocarcinoma samples. No mutation was detected in either tumour or bronchial carinae in nine patients (47%). K- ras mutation was detected in the lung tumour but not in bronchial carinae in four patients (21%), in both the lung tumour and bronchial carinae in four other patients (21%). In two patients (11%), K- ras mutation was detected in at least one bronchial carina, but not in the lung tumour. Mutations of codon 12, confirmed by sequencing analysis of ten samples, were G to T transversion, mostly TGT and GTT in bronchial carinae and lung tumours. Our data show that activated K- ras by point mutation can be present in non-neoplastic bronchial carina mucosa even when no mutation is detected in tumour samples. © 2000 Cancer Research Campaig

Fragile finance: The revenue models of oppositional news outlets in repressive regimes

For journalists promoting the free flow of information in repressive or restrictive media environments, the issue of financial sustainability is complex. Both media in exile (out-of-country news outlets feeding independent information into the country of origin) and news outlets in restrictive news environments (in-country providing counter-information) exist in flawed market situations and often rely on grant funding. This is the first academic study of the revenue streams of these media, providing scarce empirical data and a typology of funding structures of these media. This article examines three main revenue categories: grant funding, earned income and donations. The major factors influencing revenue streams compared to online media startups in open markets are discussed. The article finds significant barriers to revenue creation and identifies the need for alternative approaches, particularly partnerships, to promote economic resilience for media under threat

Un cas de pythiose cutanée chez un chien vivant en Afrique

National audienc

Cellularized alginate sheets for blood vessel reconstruction

International audienc

Un cas de pythiose cutanée chez un chien vivant en Afrique

National audienc

Validation de la pertinence d'un simulateur d'arthroscopie en réalité virtuelle pour caractériser les chirurgiens expérimentés

National audienceIntroduction: La simulation par réalité virtuelle (VR) est adaptée à l'apprentissage de l'arthroscopie. Malgré de nombreuses études, il reste néanmoins difficile de distinguer des niveaux de compétence (Construct Validity) parmi les chirurgiens expérimentés. Il semble donc adéquat de rechercher de nouvelles méthodes de mesure de compétence en utilisant l'analyse des trajectoires instrumentales au lieu des mesures couramment utilisées. Hypothèse: Nous avons émis l'hypothèse qu'une plus grande expérience en arthroscopie d’épaule serait corrélée à une meilleure performance sur simulateur VR d'arthroscopie d’épaule et que les opérateurs expérimentés partageraient des trajectoires instrumentales similaires. Matériels andamp; méthodes: Après réponse à un questionnaire standardisé, 104 trajectoires de 52 chirurgiens répartis en 2 cohortes (26 intermédiaires et 26 experts) ont été enregistrées sur simulateur d'arthroscopie. La procédure analysée était le retrait de corps étranger dans une articulation d’épaule droite. Dix mesures ont été calculées sur les trajectoires, notamment la durée de procédure, la distance instrumentale, l’économie de mouvement et la fluidité. De plus, le Dynamic Time Warping (DTW) a été calculé sur les trajectoires pour une classification hiérarchique non supervisée des chirurgiens. Résultats: Les experts furent significativement plus rapides (Médiane 70,9s Écart Interquartile [56,4–86,3] vs. 116,1s [82,8–154,2], p andlt; 0,01), plus fluides (4,6,105 mm.s−3 [3,1,105–7,2,105] vs. 1,5,106 mm.s−3 [2,6,106–3,5,106], p = 0,05), et plus économes en mouvement (19,3 mm2 [9,1–25,9] vs. 33,8 mm2 [14,8–50,5], p andlt; 0,01), mais il n'y avait pas de différence significative de performance sur la distance (671,4 mm [503,8–846,1] vs. 694,6 mm [467,0–1090,1], p = 0,62). Le clustering par DTW a différencié deux groupes de trajectoires similaires liées à l'expertise avec respectivement 48 trajectoires d'experts pour le premier groupe et 52 trajectoires d'intermédiaires et 4 d'experts pour le second groupe (Sensibilité de 92 %, Spécificité de 100 %). Le clustering hiérarchique avec DTW a identifié significativement les chirurgiens experts des intermédiaires en trouvant des trajectoires similaires pour 24/26 experts. Conclusion: Cette étude a démontré la Construct Validity du simulateur VR d'arthroscopie d’épaule au sein d'un groupe de chirurgiens expérimentés. Grâce à de nouveaux types de mesures simplement basées sur les trajectoires, il a été possible de distinguer de manière significative les niveaux d'expertise. Nous avons démontré que l'analyse par clustering avec Dynamic Time Warping est capable de distinguer de manière fiable les opérateurs experts des opérateurs intermédiaires. Pertinence clinique: Les résultats ont des implications pour l'avenir de la formation en chirurgie arthroscopique ou des programmes d'accréditation postuniversitaire utilisant la simulation par réalité virtuelle. Niveau de preuve: III; étude comparative prospective. © 2021 Elsevier Masson SA