Bioprinting has emerged as a novel technological approach with the potential to address unsolved questions in the field of tissue engineering. We have recently shown that Laser Assisted Bioprinting ...(LAB), due to its unprecedented cell printing resolution and precision, is an attractive tool for the in situ printing of a bone substitute. Here, we show that LAB can be used for the in situ printing of mesenchymal stromal cells, associated with collagen and nano-hydroxyapatite, in order to favor bone regeneration, in a calvaria defect model in mice. Also, by testing different cell printing geometries, we show that different cellular arrangements impact on bone tissue regeneration. This work opens new avenues on the development of novel strategies, using in situ bioprinting, for the building of tissues, from the ground up.
This study aimed to describe the health status of children and how social deprivation affects their use of healthcare services and mortality. Children living in mainland France were selected from the ...national health data system (SNDS) on their date of birth or birthday in 2018 (< 18 years) and followed for one year. Information included data on healthcare reimbursements, long-term chronic diseases (LTDs) eligible for 100% reimbursement, geographic deprivation index (FDep) by quintile (Q5 most disadvantaged), and individual complementary universal insurance (CMUc) status, granted to households with an annual income below the French poverty level. The number of children who had at least one annual visit or hospital admission was compared using the ratio of geographic deprivation (rQ5/Q1) and CMUc (rCMUc/Not) after gender and age-standardization. Over 13 million children were included; 17.5% had CMUc, with an increase across quintiles (rQ5/Q1 = 3.5) and 4.0% a LTD (rQ5/Q1 = 1.44). The 10 most frequent LTDs (6 psychiatric) were more common as the deprivation increased. Visits to general practitioners (GPs) were similar (≈84%) for each FDep quintile and the density of GPs similar. The density decreased with increasing deprivation for specialists and visits: paediatricians (rQ5/Q1 = 0.46) and psychiatrists (rQ5/Q1 = 0.26). Dentist visits also decreased (rQ5/Q1 = 0.86) and deprived children were more often hospitalised for dental caries (rQ5/Q1 = 2.17, 2.1% vs 0.7%). Emergency department (ED) visits increased with deprivation (rCMUc/Not = 1.35, 30% vs 22%) but 50% of CMUc children lived in a municipality with an ED vs. 25% without. Approximately 9% of children were admitted for a short stay and 4.5% for a stay > 1 night (rQ5/Q1 = 1.44). Psychiatric hospitalization was more frequent for children with CMUc (rCMUc/Not = 3.5, 0.7% vs 0.2%). Higher mortality was observed for deprived children < 18 years (rQ5/Q1 = 1.59). Our results show a lower use of pediatricians, other specialists, and dentists among deprived children that may be due, in part, to an insufficient supply of care in their area of residence. These results have been used to recommend optimization and specifically adapted individual or area-wide policies on the use of healthcare services, their density, and activities.
Abstract
Background
Nationwide data for children for short-stay hospitalisation (SSH) and associated factors are scarce. This retrospective study of children in France < 18 years of age followed ...after their birth or birthday in 2018 focused on at least one annual SSH, stay < 1 night or ≥ 1 night, or 30-day readmission ≥ 1 night.
Methods
Children were selected from the national health data system (SNDS), which includes data on long-term chronic disease (LTD) status with full reimbursement and complementary universal coverage based on low household income (CMUC). Uni and multivariate quasi-Poisson regression were applied for each outcome.
Results
Among 13.211 million children (94.4% population, 51.2% boys), CMUC was identified for 17.5% and at least one LTD for 4% (0-<1 year: 1.5%; 14-<18 year: 5.2%). The most frequent LTDs were pervasive developmental diseases (0.53%), asthma (0.24%), epilepsy (0.17%), and type 1 diabetes (0.15%). At least one SSH was found for 8.8%: SSH < 1 night (4.9%), SSH ≥ 1 night (4.5%), readmission (0.4%). Children with at least one SSH were younger (median 6 vs. 9 years) and more often had CMUC (21%), a LTD (12%), an emergency department (ED) visit (56%), or various primary healthcare visits than all children. Those with a SSH ≥1 night vs. < 1 night were older (median: 9 vs. 4 years). They had the same frequency of LTD (13.4%) but more often an ED visit (78% vs. 42%). Children with readmissions were younger (median 3 years). They had the highest levels of CMUC (29.3%), LTD (34%), EDs in their municipality (35% vs. 29% for the whole population) and ED visits (87%). In adjusted analysis, each outcome was significantly less frequent among girls than boys and more frequent for children with CMUC. LTDs with the largest association with SSH < 1 night were cystic fibrosis, sickle cell diseases (SCD), diabetes type 1, those with SSH ≥1 night type 1 diabetes epilepsy and SCD, and those for readmissions lymphoid leukaemia, malignant neoplasm of the brain, and SCD. Among all SSH admissions of children < 10 years, 25.8% were potentially preventable.
Conclusion
Higher SSH and readmission rates were found for children with certain LTD living in low-income households, suggesting the need or increase of specific policy actions and research.
The reconstruction of bones following tumor excision and radiotherapy remains a challenge. Our previous study, performed using polysaccharide-based microbeads that contain hydroxyapatite, found that ...these have osteoconductivity and osteoinductive properties. New formulations of composite microbeads containing HA particles doped with strontium (Sr) at 8 or 50% were developed to improve their biological performance and were evaluated in ectopic sites. In the current research, we characterized the materials by phase-contrast microscopy, laser dynamic scattering particle size-measurements and phosphorus content, before their implantation into two different preclinical bone defect models in rats: the femoral condyle and the segmental bone. Eight weeks after the implantation in the femoral condyle, the histology and immunohistochemistry analyses showed that Sr-doped matrices at both 8% and 50% stimulate bone formation and vascularization. A more complex preclinical model of the irradiation procedure was then developed in rats within a critical-size bone segmental defect. In the non-irradiated sites, no significant differences between the non-doped and Sr-doped microbeads were observed in the bone regeneration. Interestingly, the Sr-doped microbeads at the 8% level of substitution outperformed the vascularization process by increasing new vessel formation in the irradiated sites. These results showed that the inclusion of strontium in the matrix-stimulated vascularization in a critical-size model of bone tissue regeneration after irradiation.
Introduction : Devant le vieillissement de la population et la prévalence croissante de la maladie d’Alzheimer et des autres troubles neurocognitifs majeurs affectant les personnes âgées, les modèles ...d’hébergement conventionnels sont remis en question, ce qui a contribué à l’émergence de nouveaux modèles d’hébergement et de soins. L’objectif de l’étude est de décrire quatre milieux de vie novateurs destinés à une clientèle atteinte de troubles neurocognitifs majeurs afin de mieux comprendre les caractéristiques de ce type de modèles d’hébergement au Québec. Méthodes : Un devis de recherche descriptif, basé sur une étude de cas multiples, permet de décrire les perceptions de résidents (n=25 entrevues), de proches aidants (n=60 entrevues) ainsi que de soignants et d’employés (n=91 entrevues) sur un intervalle de 12 mois. Résultats : Cette étude permet de souligner les principales sources de satisfaction et les incontournables à la conception de ce type de milieux de vie, soit : 1) l’approche adaptée aux besoins de cette clientèle; 2) la création d’environnements physiques dégageant une ambiance familiale; 3) l’offre d’interactions sociales et d’activités occupationnelles; 4) l’organisation du travail dans le respect du rythme et des préférences des résidents; et 5) l’ouverture à la latitude décisionnelle et à la prise d’initiatives. Discussion et conclusion : S’inscrivant dans les préoccupations des instances politiques et des établissements de santé visant à favoriser l’amélioration des soins et des services pour cette clientèle, cette étude souligne les principales forces de ces milieux de vie. Ces données permettront d’éclairer les décideurs et la communauté scientifique sur certaines pratiques cliniques et organisationnelles novatrices à privilégier dans le domaine de l’hébergement pour aînés.
Background. Q fever is a zoonosis caused by Coxiella burnetii. After a large outbreak occurred in the Chamonix Valley in the French Alps in 2002, an extensive surveillance was conducted, to describe ...the variations in the clinical expression of acute Q fever according to host factors, as well as to monitor the risk of evolution of acute Q fever to chronic Q fever in patients at risk. Methods. Three groups of patients with risk factors for evolution of acute Q fever to chronic Q fever were considered: 376 pregnant women, 19 immunocompromised patients, and 91 patients with valvular or vascular abnormalities. A group of 578 people without risk factors for evolution of acute Q fever to chronic Q fever was also tested. Diagnosis of Q fever was based on serologic testing by immunofluorescence assay. Results. Between 30 August 2002 and 31 July 2003, a total of 1946 serum samples obtained from 1064 persons were tested. A total of 101 patients (9.3%) had acute Q fever diagnosed, and 5 patients (0.5%) had chronic Q fever diagnosed. A diagnosis of acute Q fever was established for 11 pregnant women (2.6% of 379 pregnancies), 5 patients with valvular disease (5.5%), and 85 people without risk factors (14.7%) (71 27.9% of 254 symptomatic patients and 14 4.3% of 324 asymptomatic patients). A new pregnancy in a woman with negative results of serologic tests for Q fever exposes the woman to a new risk for acute Q fever able to evolve to chronic Q fever. The rates of clinical expression were 90.6% in adult men, 75% in adult women, and 33.3% in children, and they were significantly lower (9.1%) in pregnant women. Evolution to chronic Q fever was observed in 5 patients. Conclusion. This study emphasizes the importance of active surveillance in postepidemic conditions, especially among patients at risk, as well as the importance of systematic serologic testing during pregnancy.
Magnetic Resonance Imaging (MRI) appears as a good surrogate to Computed Tomography (CT) scan as it does not involve radiation. In this context, a 3D anatomical and perfusion MR imaging protocol was ...developed to follow the evolution of bone regeneration and the neo-vascularization in femoral bone defects in rats. For this, three different biomaterials based on Pullulan-Dextran and containing either Fucoidan or HydroxyApatite or both were implanted. In vivo MRI, ex vivo micro-CT and histology were performed 1, 3 and 5 weeks after implantation. The high spatially resolved (156 × 182 × 195 µm) anatomical images showed a high contrast from the defects filled with biomaterials that decreased over time due to bone formation. The 3D Dynamic Contrast Enhanced (DCE) imaging with high temporal resolution (1 image/19 s) enabled to detect a modification in the Area-Under-The-Gadolinium-Curve over the weeks post implantation. The high sensitivity of MRI enabled to distinguish which biomaterial was the least efficient for bone regeneration, which was confirmed by micro-CT images and by a lower vessel density observed by histology. In conclusion, the methodology developed here highlights the efficiency of longitudinal MRI for tissue engineering as a routine small animal exam.
We have created entirely biological tissue-engineered vascular grafts (TEVGs) using sheets of cell-assembled extracellular matrix (CAM) produced by human fibroblasts in vitro. A large animal TEVG ...would allow long-term pre-clinical studies in a clinically relevant setting (graft size and allogeneic setting). Therefore, canine, porcine, ovine, and human skin fibroblasts were compared for their ability to form CAM sheets. Serum sourcing greatly influenced CAM production in a species-dependent manner. Ovine cells produced the most homogenous and strongest animal CAM sheets but remained ≈3-fold weaker than human sheets despite variations of serum, ascorbate, insulin, or growth factor supplementations. Key differences in cell growth dynamics, tissue development, and tissue architecture and composition were observed between human and ovine. This study demonstrates critical species-to-species differences in fibroblast behavior and how they pose a challenge when attempting to substitute animal cells for human cells during the development of tissue-engineered constructs that require long-term cultures.
Tissue engineering strategies aim at characterizing and at optimizing the cellular component that is combined with biomaterials, for improved tissue regeneration. Here, we present the immunoMap of ...apical papilla, the native tissue from which SCAPs are derived. We characterized stem cell niches that correspond to a minority population of cells expressing Mesenchymal stromal/Stem Cell (CD90, CD105, CD146) and stemness (SSEA4 and CD49f) markers as well as endothelial cell markers (VWF, CD31). Based on the colocalization of TKS5 and cortactin markers, we detected migration-associated organelles, podosomes-like structures, in specific regions and, for the first time, in association with stem cell niches in normal tissue. From six healthy teenager volunteers, each with two teeth, we derived twelve cell banks, isolated and amplified under 21 or 3% O
. We confirmed a proliferative advantage of all banks when cultured under 3% versus 21% O
. Interestingly, telomerase activity was similar to that of the highly proliferative hiPSC cell line, but unrelated to O
concentration. Finally, SCAPs embedded in a thixotropic hydrogel and implanted subcutaneously in immunodeficient mice were protected from cell death with a slightly greater advantage for cells preconditioned at 3% O
.
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