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Vernonia species (Asteraceae) are indigenous medicinal and food leaf vegetables commonly consumed in some African countries like Cameroon where they constitute a staple dish called "ndolé." Previous studies have demonstrated the nutritional importance of Vernonia, but there is little knowledge of their agronomic value and genetic potentials. Wide genetic variability in the genus has been established earlier through the study of its pollen. However, to the best of our understanding, no such study has been undertaken on the genetic variability of Vernonia with respect to its secondary metabolites. This study was therefore aimed at evaluating the genetic variability of Vernonia amygdalina (VAA and VALF) and V. calvoana (VCAB, VCAV, VCSB, and VCSV) morphotypes in 2016 based on secondary metabolite content and antimicrobial properties. This involved phytochemical analysis by HPLC/MS for the detection of alkaloids, flavonoids, phenols, and tannins in leaves from each of the six genotypes. Results showed that all tested genotypes are rich in phenols (18 analyzed), flavonoids, and tannins with, VAA richer in phenols (206.1 ± 3.12 µg/g of dry extract), followed by VCAV (197.9 ± 18.03 µg/g). The lowest level of flavonoid was found in VCSV (81.6 ± 7.21 µg/g), while the highest was from VCAB (132.8 ± 31.5 µg/g). VCSV (56.3 ± 4.08 µg/g) had the lowest level of tannins, while VCAB (97.8 ± 23.8 µg/g) had the highest levels. Assessment of antimicrobial activity of leaf extracts from the six genotypes was done by culture on Mueller Hinton (MH) agar and MH broth agar for bacteria and in Sabouraud dextrose agar and Sabouraud dextrose broth media for fungi, respectively. All morphotypes exhibited inhibitory activity on bacteria except VAA, with isoquercetin characteristic of VCSV. Chemotaxonomic analyses of Vernonia morphotypes highlighted the genetic diversity within species and variability of antimicrobial properties of ethanolic leaf extracts among morphotypes. These results provide baseline data in the valuation of genetic resources and the establishment of improvement programs.

Summary Background Coarctation of the aorta (CoA) is still challenging to diagnose in neonates with patent ductus arteriosus (PDA). Speckle tracking echocardiography allows reliable analysis of myocardial deformation in newborns and seems to provide important insides into regional changes in patients with left ventricular (LV) outflow tract obstruction. Aims To assess the interest of LV global longitudinal strain (GLS) measurement for predicting CoA in neonates with PDA and prenatal suspicion. Methods Prospective single-center study. Twenty-two newborns with prenatal suspicion of CoA were included. All newborns were evaluated in the first 12 hours of life. To assess the feasibility and the reproducibility of GLS, 14 healthy full-term newborns with PDA (group 3) were screened. CoA was diagnosed when DA closed, according to usual echocardiographic criteria. Results Six neonates developed CoA after DA closure (group 1) whereas 16 did not (group 2). Mean gestational age and birth weight were not different between the groups. GLS measurements were possible in 100%. Intra- and inter-observer variability of strain measurements was acceptable. GLS values were significantly lower in neonates who developed CoA (P = 0.015). To predict CoA, cut-off value of −17.42% gave the best compromise for sensitivity (83%) and specificity (72%). Aortic arch dimensions were modestly correlated with strain values. The presence of a bicuspid aortic valve was not associated with significant lower GLS values. Conclusion LV GLS analysis is a feasible and reproducible echocardiographic technique in newborns with PDA. Newborns who will develop CoA seem to have lower values of GLS than healthy neonates. Further studies are needed to confirm these preliminary results.

The study of pollen dispersal and mode of fertilization of Vernonia amygdalina and Vernonia calvoana is a prerequisite to the understanding of genetic diversity and elaboration of improvement programs for the Vernonia genus. In this study, precise experimental designs were made for morphological and biological observations on Vernonia species capitulum in order to assess the distinctive effects of each of the three possible pollen transportation agents (insects, wind and rain water) on pollination. Results obtained show that the exclusive mode of pollen dispersal is entomophilous. Even though allogamy and autogamy are observed as two possible modes of fertilization in Vernonia spp., some arguments tend to favour allogamy. However, there is no clear cut position on the issue, hence the need for confirmation by further experimentation in controlled pollination. This study paves the way for the establishment of a genetic improvement program for this genus based on the results on pollen dispersal. Key words: Vernonia species, allogamy, autogamy, pollination agent.

The mechanisms underlying pulmonary hypertension (PH) are complex and multifactorial, and involve different cell types that are interconnected through gap junctional channels. Although connexin (Cx)-43 is the most abundant gap junction protein in the heart and lungs, and critically governs intercellular signalling communication, its contribution to PH remains unknown. The focus of the present study is thus to evaluate Cx43 as a potential new target in PH.Expressions of Cx37, Cx40 and Cx43 were studied in lung specimens from patients with idiopathic pulmonary arterial hypertension (IPAH) or PH associated with chronic hypoxaemic lung diseases (chronic hypoxia-induced pulmonary hypertension (CH-PH)). Heterozygous Cx43 knockdown CD1 (Cx43+/−) and wild-type littermate (Cx43+/+) mice at 12 weeks of age were randomly divided into two groups, one of which was maintained in room air and the other exposed to hypoxia (10% oxygen) for 3 weeks. We evaluated pulmonary haemodynamics, remodelling processes in cardiac tissues and pulmonary arteries (PAs), lung inflammation and PA vasoreactivity.Cx43 levels were increased in PAs from CH-PH patients and decreased in PAs from IPAH patients; however, no difference in Cx37 or Cx40 levels was noted. Upon hypoxia treatment, the Cx43+/− mice were partially protected against CH-PH when compared to Cx43+/+ mice, with reduced pulmonary arterial muscularisation and inflammatory infiltration. Interestingly, the adaptive changes in cardiac remodelling in Cx43+/− mice were not affected. PA contraction due to endothelin-1 (ET-1) was increased in Cx43+/− mice under normoxic and hypoxic conditions.Taken together, these results indicate that targeting Cx43 may have beneficial therapeutic effects in PH without affecting compensatory cardiac hypertrophy.

The focusing cubic NLS is a canonical model for the propagation of laser beams. In dimensions 2 and 3, it is known that a large class of initial data leads to finite time blow-up. Now, physical experiments suggest that this blow-up does not always occur. This might be explained by the fact that some physical phenomena neglected by the standard NLS model become relevant at large intensities of the beam. Many ad hoc variants of the focusing NLS equation have been proposed to capture such effects. In this paper, we derive some of these variants from Maxwell's equations and propose some new ones. We also provide rigorous error estimates for all the models considered. Finally, we discuss some open problems related to these modified NLS equations.

Background and objectives Chronic hypoxemia induces pulmonary hypertension (PH) leading to cardiac insufficiency, and fish oil (EPA+DHA) seems beneficial to prevent PH. We aimed at investigating the effects of DHA from glycerophospholipids (GPL-DHA) or from algal oil (triglycerides) in preventing experimental PH and heart insufficiency. Procedure The study was conducted in Wistar males rats (n=10 per group) over 7 weeks: a control group (C) in normoxic conditions, two groups maintained in normoxic conditions for 4 weeks and under hypoxic conditions (hypobaric chamber, 0.5 Bar) for the last 3 weeks receiving no DHA (H) or 60-120 mg/kg/ day of DHA as GPL (GPL-D60, GPL-D120) or triglycerides (TG-D120). The thickness of the right ventricle (RV) and the pulmonary artery acceleration time (PAAT) were measured weekly by echocardiography. At the end of the study, pulmonary artery pressure (PAP, invasive catheterization) and the fatty acid profile of lungs and heart were determined. Statistics were done by Mann-Whitney test (p Results Hypoxemia led to i) a high increase of the thickness of the RV and RV hypertrophy, ii) a decrease in PAAT (increase in vascular resistance), ii) a change in DHA level in heart (increase) and in lungs (decrease). The DHA supplementation i) limitated the development of RV dysfunction (–19%/–24% thickness), ii) attenuated the decrease in PAAT (+41% or +76% for GPLDHA60 or 120, +46% for TG-DHA120) and the vascular resistance (–12% PAP), iii) increased DHA level slightly in heart (C: 9.3±2.0a; H: 12.4±3.0b; GPL-D60: 14.2±4.4bc; GPL-D120: 15.6±2.8c; TG-DHA120: 14.3±1.5bc) and highly in lungs (C: 2.1±0.2a; H: 1.9±0.2b; GPL-D60: 2.5±0.4c; GPL-D120: 3.5±0.9d; TG-DHA120: 3.7±0.8d). Conclusions GPL-DHA and TG-DHA partially prevented PH and cardiac remodeling. The effects seem not related only to the total level of DHA in tissues suggesting plausible changes in phospholipid classes. The author hereby declares no conflict of interest

In this thesis, we present 3 different projects that aim to support clinical translation in neonatal lung research.First, we use state-of-the-art approach to study normal human lung development at a single-cell level. We report the cellular composition, cell trajectories and cell-to-cell communication in developing human lungs with single nuclei RNA sequencing (snRNA-seq) on 23.251 nuclei isolated from nine human fetuses with gestational ages between 14 to 19 weeks of gestation. We describe nine different cell types, including rare cell populations such as pulmonary neuroendocrine cells. For each cell type, marker genes are reported and use for spatial validation using fluorescent RNA in situ hybridization. Enrichment and developmental trajectory analysis provide insight into molecular mechanisms and signaling pathways changes within cell type according to gestational age. Last, ligand-receptor analysis highlights determinants of cell-to-cell communication among the different cell types. These findings will provide a clinically relevant background for research hypotheses generation in projects studying normal or impaired lung development and help to develop and validate surrogate models to study human lung development such as human lung organoids.Second, we use a model of organotypic culture called Precision Cut Lung Slices (PCLS) from human fetal lung tissue to validate the clinical relevance of a viral vector (Adeno-associated virus AAV) for gene therapy for surfactant B deficiency in neonates. We develop a protocol to obtain and culture PCLS from human fetal lung tissues. We reported that these PCLS can be maintained up to 7 days in culture with a preserved metabolic activity and architecture. These PCLS were then successfully used to provide proof of concept that the AAV vector can efficiently transfect human lung parenchyma. PCLS were incubated at day 3 of culture with different titers of AAV (and with different cargos: mouse SPB and human SPB) for 24 hours. On day 7 of culture, we confirmed by bioluminescence and immunofluorescence that AAV can transfect human lung parenchyma with a dose dependent effect. Furthermore, assessment of the PCLS (by metabolic activity and architecture) demonstrated the absence of adverse effects on human lung tissue transfected by AAV vector. Therefore, PCLS from human lung tissue (healthy or diseased) represent a versatile tool to assess pathophysiology or therapeutics in an organotypic culture setting. It aligns with the need for more complex and holistic models and the use of human tissue in translational research.Last, we aim to develop a consensus definition for Mesenchymal Stromal Cell (MSC) and reporting guidelines for clinical trials of MSC therapy to enhance rigour, reproducibility, transparency in the MSC research and ultimately the safe translation of effective cell-based therapies in humans. Our research protocol uses the unique attributes of a consensus-building method called modified Delphi method in combination with an ‘integrated knowledge translation’ approach where key stakeholders and end-users are involved from inception and participate in every step of the study to support dissemination and implementation of the findings. We present here our detailed research protocol, and the results of a scoping review conducted to describe how MSC were defined and characterized in preclinical and clinical research. In this scoping review, we report that previous minimal criteria to define MSC provided by the International Society for Cell and Gene Therapy (ISCT) were poorly implemented with inconstant reporting among in both preclinical and clinical studies. More concerning, the clinical studies showed inconsistent completeness in reporting relevant and important information on MSC characterization and cell manufacturing processes. This project highlights important points for consensus-building strategies and the critical step of knowledge translation in translational research., Dans ce travail, nous rapportons 3 projets visant à améliorer et soutenir la translation clinique en recherche sur le poumon néonatal.Premièrement, nous décrivons l’utilisation du séquençage d'ARN sur noyaux uniques (single nuclei RNA sequencing ou snRNA-seq) pour étudier le développement pulmonaire humain. Le snRNAseq sur 23,251 noyaux cellulaires isolés à partir de neuf fœtus humains (âges gestationnels de 14 à 19 semaines de gestation) a permis de décrire neuf types cellulaires, incluant des populations cellulaires rares telles que les cellules pulmonaires neuroendocrines. Pour chaque type cellulaire, des gènes marqueurs ont été identifiés et utilisés pour confirmer la répartition spatiale cellulaire au sein du tissu par hybridation in situ en fluorescence (FISH). Les analyses d’enrichissement et de trajectoires développementales ont permis de décrire les modifications des voies moléculaires et de signalisation au sein d’un même type cellulaire en fonction de l'âge gestationnel. L’analyse des interactions ligands-récepteurs a mis en évidence les voies de communications entre les différents types cellulaires. Ces résultats offrent une perspective clinique majeure pour générer des hypothèses de recherche pertinentes pour tout projet étudiant le développement pulmonaire normal ou altéré et développer et valider des modèles de substitution pour étudier le développement pulmonaire humain (organoïdes pulmonaires humains).Le second projet décrit l’utilisation de culture organotypique dérivée de tissu pulmonaire humain pour valider l’utilisation potentielle chez l’humain d’un virus adéno-associé (AAV pour adeno-associated virus) comme vecteur de thérapie génique pour traiter le déficit en protéine B du surfactant pulmonaire. Nous avons développé un modèle de “precision cut lung slices” (PCLS) obtenues à partir de poumons fœtaux humains, ces PCLS pouvaient être maintenues en culture et conserver leur activité métabolique et architecture pendant plus de 7 jours. Les PCLS ont ensuite été utilisées pour valider avec succès la transfection du vecteur AAV dans le parenchyme pulmonaire humain. Cette transfection suivait un effet dose-dépendant et ne présentait pas d’effet délétère (évalué par le niveau d’activité métabolique et l’architecture des PCLS). Ces données démontrent l’intérêt des PCLS issues de poumons humains pour évaluer des thérapeutiques, soulignant l’importance de modèles expérimentaux complexes utilisant du tissu humain en recherche translationnelle.Le troisième projet vise à développer une définition consensuelle pour les cellules stromales mésenchymateuses (Mesenchymal Stromal Cells ou MSC) et des lignes directrices pour reporter des essais cliniques utilisant des MSC pour améliorer la rigueur, la reproductibilité, la transparence de la recherche utilisant les MSC afin de garantir une translation sûre de thérapies cellulaires efficaces en clinique. Notre protocole de recherche combine une méthodologie utilisée pour le développement de consensus appelée méthode Delphi en combinaison avec une stratégie de transmission des connaissances. Nous présentons ici notre protocole de recherche détaillé et les résultats d'une synthèse de la littérature (scoping review) menée pour décrire comment les MSC sont définies et caractérisées en recherche préclinique et clinique. L’analyse de notre échantillon d’études originales a mis en évidence une grande variabilité et des incohérences dans la description des MSC, leurs caractéristiques et leurs conditions de culture. De plus, la majorité des essais cliniques rapportaient de façon variable et non exhaustive ces caractéristiques importantes des MSC. Ce projet souligne l'importance du choix de la méthode d'élaboration de consensus et l’aspect fondamental des stratégies de transmission de savoir en recherche translationnelle.