RÉSUMÉ
The human head can sometimes experience impact loads that result in skull fractures or other injuries, leading to the need for a craniectomy. Cranioplasty is a procedure that involves replacing the removed portion with either autologous bone or alloplastic material. While titanium has traditionally been the preferred material for cranial implants due to its excellent properties and biocompatibility, its limitations have prompted the search for alternative materials. This research aimed to explore alternative materials to titanium for cranial implants in order to address the limitations of titanium implants and improve the performance of the cranioplasty process. A 3D model of a defective skull was reconstructed with a cranial implant, and the implant was simulated using various stiff and soft materials (such as alumina, zirconia, hydroxyapatite, zirconia-reinforced PMMA, and PMMA) as alternatives to titanium under 2000N impact forces. Alumina and zirconia implants were found to reduce stresses and strains on the skull and brain compared to titanium implants. However, PMMA implants showed potential for causing skull damage under current loading conditions. Additionally, PMMA and hydroxyapatite implants were prone to fracture. Despite these findings, none of the implants exceeded the limits for tensile and compressive stresses and strains on the brain. Zirconia-reinforced PMMA implants were also shown to reduce stresses and strains on the skull and brain compared to PMMA implants. Alumina and zirconia show promise as alternatives to titanium for the production of cranial implants. The use of alternative implant materials to titanium has the potential to enhance the success of cranial reconstruction by overcoming the limitations associated with titanium implants.
Sujet(s)
Matériaux biocompatibles , Analyse des éléments finis , Test de matériaux , , Crâne , Contrainte mécanique , Titane , Zirconium , Humains , Crâne/chirurgie , Titane/composition chimique , Matériaux biocompatibles/composition chimique , Zirconium/composition chimique , /méthodes , Prothèses et implants , Durapatite/composition chimique , Poly(méthacrylate de méthyle)/composition chimique , Oxyde d'aluminium/composition chimique , Résistance à la traction , Fractures du crâne/chirurgie , Résistance à la compressionRÉSUMÉ
Cranial sutures separate neighboring skull bones and are sites of bone growth. A key question is how osteogenic activity is controlled to promote bone growth while preventing aberrant bone fusions during skull expansion. Using single-cell transcriptomics, lineage tracing, and mutant analysis in zebrafish, we uncover key developmental transitions regulating bone formation at sutures during skull expansion. In particular, we identify a subpopulation of mesenchyme cells in the mid-suture region that upregulate a suite of genes including BMP antagonists (e.g. grem1a) and pro-angiogenic factors. Lineage tracing with grem1a:nlsEOS reveals that this mid-suture subpopulation is largely non-osteogenic. Moreover, combinatorial mutation of BMP antagonists enriched in this mid-suture subpopulation results in increased BMP signaling in the suture, misregulated bone formation, and abnormal suture morphology. These data reveal establishment of a non-osteogenic mesenchyme population in the mid-suture region that restricts bone formation through local BMP antagonism, thus ensuring proper suture morphology.
Sujet(s)
Protéines morphogénétiques osseuses , Sutures crâniennes , Mésoderme , Ostéogenèse , Protéines de poisson-zèbre , Danio zébré , Animaux , Danio zébré/embryologie , Danio zébré/génétique , Sutures crâniennes/métabolisme , Sutures crâniennes/embryologie , Sutures crâniennes/croissance et développement , Protéines de poisson-zèbre/métabolisme , Protéines de poisson-zèbre/génétique , Protéines morphogénétiques osseuses/métabolisme , Protéines morphogénétiques osseuses/génétique , Mésoderme/métabolisme , Mésoderme/embryologie , Mésoderme/cytologie , Régulation de l'expression des gènes au cours du développement , Transduction du signal , Crâne/embryologie , Analyse sur cellule unique , MutationRÉSUMÉ
The study of evolutionary rates and patterns is the key to understand how natural selection shaped the current and past diversity of phenotypes. Phylogenetic comparative methods offer an array of solutions to undertake this challenging task, and help understanding phenotypic variation in full in most circumstances. However, complex, three-dimensional structures such as the skull and the brain serve disparate goals, and different portions of these phenotypes often fulfil different functions, making it hard to understand which parts truly were recruited by natural selection. In the recent past, we developed tools apt to chart evolutionary rate and patterns directly on three-dimensional shapes, according to their magnitude and direction. Here, we present further developments of these tools, which now allow to restitute the mapping of rates and patterns with full biological realism. The tools are condensed in a new R software package.
Sujet(s)
Évolution biologique , Phénotype , Phylogenèse , Logiciel , Animaux , Imagerie tridimensionnelle , Crâne/anatomie et histologie , Humains , Sélection génétiqueRÉSUMÉ
Cranioplasty is the surgical repair of a bone defect in the skull resulting from a previous operation or injury, which involves lifting the scalp and restoring the contour of the skull with a graft made from material that is reconstructed from scans of the patient's own skull. The paper introduces a 3D printing technology in creating molds, which are filled with polymethyl methacrylate (PMMA) to reconstruct the missing bone part of the skull. The procedure included several steps to create a 3D model in an STL format, conversion into a G-code which is further used to produce the mold itself using a 3D printer. The paper presents our initial experience with 5 patients who undergone cranioplasty utilizing 3D printed molds. Making a patient-specific model is a very complex process and consists of several steps. The creation of a patient-specific 3D model loading of DICOM images obtained by CT scanning, followed by thresholding-based segmentation and generation of a precise 3D model of part of the patient's skull. Next step is creating the G-code models for 3D printing, after which the actual models are printed using Fused Deposition Modeling printer and PLA material. All surgeries showed good match of the missing bone part and part created using 3D printed mold, without additional steps in refinement. In such a way, 3D printing technology helps in creating personalized and visually appealing bone replacements, at a low cost of the final product.
Sujet(s)
, Impression tridimensionnelle , Crâne , Humains , Crâne/chirurgie , Crâne/imagerie diagnostique , /instrumentation , /méthodes , Poly(méthacrylate de méthyle) , Tomodensitométrie , Médecine de précision , MâleRÉSUMÉ
Considering the lack of consensus related to the impact of selective IL-6 receptor inhibition on bone remodeling and the scarcity of reports, especially on large bone defects, this study proposed to evaluate the biological impact of the selective inhibitor of interleukin-6 receptor (tocilizumab) in an experimental model of critical calvarial defect in rats. In this preclinical and in vivo study, 24 male Wistar rats were randomly divided into two groups (n=12/group): defect treated with collagen sponge (CG) and defect treated with collagen sponge associated with 2 mg/kg tocilizumab (TCZ). The defect in the parietal bone was created using an 8-mm diameter trephine drill. After 90 days, the animals were euthanized, and tissue samples (skull caps) were evaluated through micro-CT, histological, immunohistochemistry, cytokines, and RT-qPCR analyses. Tocilizumab reduced mononuclear inflammatory infiltration (P<0.05) and tumor necrosis factor (TNF)-α levels (P<0.01) and down-regulated tissue gene expression of BMP-2 (P<0.001), RUNX-2 (P<0.05), and interleukin (IL)-6 (P<0.05). Moreover, it promoted a stronger immunostaining of cathepsin and RANKL (P<0.05). Micro-CT and histological analyses revealed no impact on general bone formation (P>0.05). The bone cells (osteoblasts, osteoclasts, and osteocytes) in the defect area were similar in both groups (P>0.05). Tocilizumab reduced inflammatory cytokines, decreased osteogenic protein, and increased proteases in a critical bone defect in rats. Ninety days after the local application of tocilizumab in the cranial defect, we did not find a significant formation of bone tissue compared with a collagen sponge.
Sujet(s)
Cytokines , Modèles animaux de maladie humaine , Rat Wistar , Récepteurs à l'interleukine-6 , Crâne , Animaux , Mâle , Cytokines/métabolisme , Récepteurs à l'interleukine-6/antagonistes et inhibiteurs , Crâne/effets des médicaments et des substances chimiques , Rats , Anticorps monoclonaux humanisés/pharmacologie , Anticorps monoclonaux humanisés/usage thérapeutique , Microtomographie aux rayons X , Peptide hydrolases/métabolisme , Immunohistochimie , Répartition aléatoireRÉSUMÉ
PURPOSE: Decompressive craniectomy is occasionally performed as a life-saving neurosurgical intervention in patients with acute severe brain injury to reduce refractory intracranial hypertension. Subsequently, cranioplasty (CP) is performed to repair the skull defect. In the meantime, patients are living without cranial bone protection, and little is known about their daily life. This study accordingly explored daily life among patients living without cranial bone protection after decompressive craniectomy while awaiting CP. METHODS: A multiple-case study examined six purposively sampled patients, patients' family members, and healthcare staff. The participants were interviewed and the data were analyzed using qualitative content analysis. RESULTS: The cross-case analysis identified five categories: "Adapting to new ways of living," "Constant awareness of the absence of cranial bone protection," "Managing daily life requires available staff with adequate qualifications," "Impact of daily life depends on the degree of recovery," and "Daily life stuck in limbo while awaiting cranioplasty." The patients living without cranial bone protection coped with daily life by developing new habits and routines, but the absence of cranial bone protection also entailed inconveniences and limitations, particularly among the patients with greater independence in their everyday living. Time spent awaiting CP was experienced as being in limbo, and uncertainty regarding planning was perceived as frustrating. CONCLUSION: The results indicate a vulnerable group of patients with brain damage and communication impairments struggling to find new routines during a waiting period experienced as being in limbo. Making this period safe and reducing some problems in daily life for those living without cranial bone protection calls for a person-centered approach to care involving providing contact information for the correct healthcare institution and individually planned scheduling for CP.
Sujet(s)
Craniectomie décompressive , Recherche qualitative , Crâne , Humains , Mâle , Craniectomie décompressive/méthodes , Femelle , Adulte , Adulte d'âge moyen , Crâne/chirurgie , Activités de la vie quotidienne , /méthodes , Sujet âgé , Lésions encéphaliques/chirurgie , Hypertension intracrânienne/chirurgie , Hypertension intracrânienne/prévention et contrôleRÉSUMÉ
Purpose: The treatment of craniofacial bone defects caused by trauma, tumors, and infectious and degenerative diseases is a significant issue in current clinical practice. Following the rapid development of bone tissue engineering (BTE) in the last decade, bioactive scaffolds coupled with multifunctional properties are in high demand with regard to effective therapy for bone defects. Herein, an innovative bone scaffold consisting of GO/Cu nanoderivatives and GelMA-based organic-inorganic hybrids was reported for repairing full-thickness calvarial bone defect. Methods: In this study, motivated by the versatile biological functions of nanomaterials and synthetic hydrogels, copper nanoparticle (CuNP)-decorated graphene oxide (GO) nanosheets (GO/Cu) were combined with methacrylated gelatin (GelMA)-based organic-inorganic hybrids to construct porous bone scaffolds that mimic the extracellular matrix (ECM) of bone tissues by photocrosslinking. The material characterizations, in vitro cytocompatibility, macrophage polarization and osteogenesis of the biohybrid hydrogel scaffolds were investigated, and two different animal models (BALB/c mice and SD rats) were established to further confirm the in vivo neovascularization, macrophage recruitment, biocompatibility, biosafety and bone regenerative potential. Results: We found that GO/Cu-functionalized GelMA/ß-TCP hydrogel scaffolds exhibited evidently promoted osteogenic activities, M2 type macrophage polarization, increased secretion of anti-inflammatory factors and excellent cytocompatibility, with favorable surface characteristics and sustainable release of Cu2+. Additionally, improved neovascularization, macrophage recruitment and tissue integration were found in mice implanted with the bioactive hydrogels. More importantly, the observations of microCT reconstruction and histological analysis in a calvarial bone defect model in rats treated with GO/Cu-incorporated hydrogel scaffolds demonstrated significantly increased bone morphometric values and newly formed bone tissues, indicating accelerated bone healing. Conclusion: Taken together, this BTE-based bone repair strategy provides a promising and feasible method for constructing multifunctional GO/Cu nanocomposite-incorporated biohybrid hydrogel scaffolds with facilitated osteogenesis, angiogenesis and immunoregulation in one system, with the optimization of material properties and biosafety, it thereby demonstrates great application potential for correcting craniofacial bone defects in future clinical scenarios.
Sujet(s)
Régénération osseuse , Cuivre , Graphite , Hydrogels , Rat Sprague-Dawley , Crâne , Ingénierie tissulaire , Structures d'échafaudage tissulaires , Animaux , Régénération osseuse/effets des médicaments et des substances chimiques , Structures d'échafaudage tissulaires/composition chimique , Cuivre/composition chimique , Cuivre/pharmacologie , Graphite/composition chimique , Hydrogels/composition chimique , Hydrogels/pharmacologie , Crâne/effets des médicaments et des substances chimiques , Crâne/traumatismes , Rats , Souris , Ingénierie tissulaire/méthodes , Ostéogenèse/effets des médicaments et des substances chimiques , Souris de lignée BALB C , Matériaux biocompatibles/composition chimique , Matériaux biocompatibles/pharmacologie , Mâle , Nanoparticules métalliques/composition chimique , Nanostructures/composition chimique , Gélatine/composition chimique , Cellules RAW 264.7RÉSUMÉ
While brain size in primates and their relatives within Euarchontoglires is well-studied, less research has examined brain shape, or the allometric trajectories that underlie the relationship between size and shape. Defining these patterns is key to understanding evolutionary trends. 3D geometric morphometric analyses of endocranial shape were performed on 140 species of extant euarchontoglirans using digital cranial endocasts. Principal component analyses on Procrustes shape variables show a clear phylogenetic pattern in endocranial shape, supported by an ANOVA which identified significant differences in shape among several groups (e.g., Platyrrhini, Strepsirrhini, Scandentia, Rodentia, and Lagomorpha). ANOVAs of shape and size also indicate that allometry has a small but significant impact on endocranial shape across Euarchontoglires, with homogeneity of slopes tests finding significant differences in the scaling relationship between shape and size among these same groups. While most of these clades possess a distinct endocranial morphotype, the highly derived platyrrhines display the strongest relationship between size and shape. Rodents show the most diversity in endocranial shape, potentially attributed to their comparatively weak relationship between shape and size. These results suggest fundamental differences in how shape and size covary among Euarchontoglires, which may have facilitated the adaptive radiations that characterize members of this group.
Sujet(s)
Évolution biologique , Phylogenèse , Crâne , Animaux , Crâne/anatomie et histologie , Fossiles/anatomie et histologie , Analyse en composantes principales , Encéphale/anatomie et histologie , Primates/anatomie et histologieRÉSUMÉ
The design of three-dimensional (3D) scaffolds should focus on creating highly porous, 3D structures with an interconnected pore network that supports cell growth. The scaffold's pore interconnectivity is directly linked to vascularization, cell seeding, guided cell migration, and transportation of nutrients and metabolic waste. In this study, different types of food flavors including monosodium glutamate, sugar, and sodium chloride were used as the porogens along with PCL/PVP blend polymer for solvent casting/particulate leaching method. The morphology, porosity, interconnectivity, chemical composition, water absorption, and mechanical properties of the fabricated scaffolds are carefully characterized. The scaffolds are biocompatible in bothin vitroandin vivoexperiments and do not trigger any inflammatory response while enhancing new bone formation and vascularization in rabbit calvaria critical-sized defects. The new bone merges and becomes denser along with the experiment timeline. The results indicate that the 3D PCL/PVP scaffolds, using monosodium glutamate as porogen, exhibited suitable biological performance and held promise for bone tissue engineering in oral and maxillofacial surgery.
Sujet(s)
Matériaux biocompatibles , Glutamate de sodium , Solvants , Ingénierie tissulaire , Structures d'échafaudage tissulaires , Animaux , Structures d'échafaudage tissulaires/composition chimique , Lapins , Ingénierie tissulaire/méthodes , Porosité , Solvants/composition chimique , Matériaux biocompatibles/composition chimique , Matériaux biocompatibles/pharmacologie , Polyesters/composition chimique , Test de matériaux , Crâne/effets des médicaments et des substances chimiques , Polyvinyles/composition chimique , Régénération osseuse/effets des médicaments et des substances chimiques , Ostéogenèse/effets des médicaments et des substances chimiques , Substituts osseux/composition chimique , Substituts osseux/pharmacologie , Os et tissu osseux/métabolismeRÉSUMÉ
Constraint is a fundamental concept in evolutionary theory. Morphology and ecology both are limited by functional, historical and developmental factors to a subset of the theoretical range species could occupy. Cat-like carnivorans (Feliformia) offer a unique opportunity to investigate phenotypic constraint, as several feliform clades are purported to be limited to generalized ecomorphological roles, while others possess extremely specialized durophagous (bone-crushing) and sabretooth morphology. We investigated the evolutionary history of feliforms by considering their phylogeny, morphological disparity and rates of evolution. We recover results that show a mosaic pattern exists in the degree of morphological disparity per anatomical region per clade and ecology. Non-hypercarnivores, such as viverrids (civets and genets), Malagasy euplerids and lophocyonids (extinct hypocarnivores), have the greatest dental disparity, while hypercarnivores (felids, nimravids, many hyaenids) have the lowest dental disparity but highest cranial and mandibular disparity (excluding dentition). However, high disparity is not necessarily associated with high rates of evolution, but instead with ecological radiations. We reveal that relationships between specialization and disparity are not as simple as past research has concluded. Instead, morphological disparity results from an anatomical mosaic of evolution, where different ecologies correlate with and likely channel unique patterns/combinations of disparity per anatomical partition.
Sujet(s)
Évolution biologique , Phylogenèse , Animaux , Crâne/anatomie et histologie , Fossiles/anatomie et histologieRÉSUMÉ
Fossil identification practices have a profound effect on our interpretation of the past because these identifications form the basis for downstream analyses. Therefore, well-supported fossil identifications are necessary for examining the impact of past environmental changes on populations and communities. Here we apply an apomorphic identification framework in a case study identifying fossil lizard remains from Hall's Cave, a late Quaternary fossil site located in Central Texas, USA. We present images and descriptions of a broad comparative sample of North American lizard cranial elements and compile new and previously reported apomorphic characters for identifying fossil lizards. Our fossil identifications from Hall's Cave resulted in a minimum of 11 lizard taxa, including five lizard taxa previously unknown from the site. Most of the identified fossil lizard taxa inhabit the area around Hall's Cave today, but we reinforce the presence of an extirpated species complex of horned lizard. A main goal of this work is to establish a procedure for making well-supported fossil lizard identifications across North America. The data from this study will assist researchers endeavoring to identify fossil lizards, increasing the potential for novel discoveries related to North American lizards and facilitating more holistic views of ancient faunal assemblages.
Sujet(s)
Fossiles , Lézards , Crâne , Animaux , Fossiles/anatomie et histologie , Lézards/anatomie et histologie , Crâne/anatomie et histologie , Texas , GrottesRÉSUMÉ
Therocephalia are an important clade of non-mammalian therapsids that evolved a diverse array of morphotypes and body sizes throughout their evolutionary history. The postcranial anatomy of therocephalians has largely been overlooked, but remains important towards understanding aspects of their palaeobiology and phylogenetic relationships. Here, we provide the first postcranial description of the large akidnognathid eutherocephalian Moschorhinus kitchingi by examining multiple specimens from fossil collections in South Africa. We also compare the postcranial anatomy with previously described therocephalian postcranial material and provide an updated literature review to ensure a reliable foundation of comparison for future descriptive work. Moschorhinus shares all the postcranial features of eutherocephalians that differentiate them from early-diverging therocephalians, but is differentiated from other eutherocephalian taxa by aspects concerning the scapula, interclavicle, sternum, manus, and femur. The novel anatomical data from this contribution shows that Moschorhinus possessed a stocky bauplan with a particularly robust scapula, humerus, and femur. These attributes, coupled with the short and robust skull bearing enlarged conical canines imply that Moschorhinus was well equipped to grapple with and subdue prey items. Additionally, the combination of these attributes differ from those of similarly sized coeval gorgonopsians, which would have occupied a similar niche in late Permian ecosystems. Moreover, Moschorhinus was the only large carnivore known to have survived the Permo-Triassic mass extinction. Thus, the subtle but important postcranial differences may suggest a type of niche partitioning in the predator guild during the Permo-Triassic mass extinction interval.
Sujet(s)
Évolution biologique , Fossiles , Animaux , République d'Afrique du Sud , Phylogenèse , Crâne/anatomie et histologie , Dinosaures/anatomie et histologie , Dinosaures/physiologie , Os et tissu osseux/anatomie et histologieRÉSUMÉ
With increases in life expectancy, the number of patients requiring joint replacement therapy and experiencing periprosthetic osteolysis, the most common complication leading to implant failure, is growing or underestimated. In this study, we found that osteolysis progression and osteoclast differentiation in the surface of the skull bone of adult mice were accompanied by significant expansion of lymphatic vessels within bones. Using recombinant VEGF-C protein to activate VEGFR3 and promote proliferation of lymphatic vessels in bone, we counteracted excessive differentiation of osteoclasts and osteolysis caused by titanium alloy particles or inflammatory cytokines LPS/TNF-α. However, this effect was not observed in aged mice because adipogenically differentiated mesenchymal stem cells (MSCs) inhibited the response of lymphatic endothelial cells to agonist proteins. The addition of the JAK inhibitor ruxolitinib restored the response of lymphatic vessels to external stimuli in aged mice to protect against osteolysis progression. These findings suggest that inhibiting SASP secretion by adipogenically differentiated MSCs while activating lymphatic vessels in bone offers a new method to prevent periprosthetic osteolysis during joint replacement follow-up.
Sujet(s)
Vaisseaux lymphatiques , Cellules souches mésenchymateuses , Ostéolyse , Animaux , Ostéolyse/prévention et contrôle , Souris , Vaisseaux lymphatiques/effets des médicaments et des substances chimiques , Vaisseaux lymphatiques/métabolisme , Cellules souches mésenchymateuses/métabolisme , Cellules souches mésenchymateuses/effets des médicaments et des substances chimiques , Vieillissement , Souris de lignée C57BL , Ostéoclastes/métabolisme , Ostéoclastes/effets des médicaments et des substances chimiques , Différenciation cellulaire/effets des médicaments et des substances chimiques , Mâle , Phénotype , Facteur de croissance endothéliale vasculaire de type C/métabolisme , Facteur de croissance endothéliale vasculaire de type C/génétique , Crâne/anatomopathologie , Crâne/effets des médicaments et des substances chimiques , Récepteur-3 au facteur croissance endothéliale vasculaire/métabolisme , Récepteur-3 au facteur croissance endothéliale vasculaire/génétique , TitaneRÉSUMÉ
The mechanosensory lateral line (LL) system of salmonid fishes has been the focus of comparative morphological studies and behavioral and physiological analyses of flow sensing capabilities, but its morphology and development have not been studied in detail in any one species. Here, we describe the post-embryonic development of the cranial LL system in Brook Trout, Salvelinus fontinalis, using vital fluorescent staining (4-Di-2-ASP), scanning electron microscopy, µCT, and clearing and staining to visualize neuromasts and the process of cranial LL canal morphogenesis. We examined the relationship between the timing of LL development, the prolonged life history of salmonids, and potential ecological implications. The LL system is composed of seven canals containing canal neuromasts (CNs) and four lines of superficial neuromasts (SNs) on the skin. CNs and SNs increase in number and size during the alevin (larval) stage. CN number stabilizes as canal morphogenesis commences, but SN number increases well into the parr (juvenile) stage. CNs become larger and more elongated than SNs, but the relative area occupied by sensory hair cells decreases during ontogeny in both types of neuromasts. Neuromast-centered canal morphogenesis starts in alevins (yolk sac larvae), as they swim up into the water column from their gravel nests (~4 months post-fertilization), after which yolk sac absorption is completed and exogenous feeding begins. Canal morphogenesis proceeds asynchronously within and among canal series and is not complete until ~8 months post-fertilization (the parr stage). Three characters in the LL system and associated dermal bones were used to identify their homologs in other actinopterygians and to consider the evolution of LL canal reduction, thus demonstrating the value of salmonids for the study of LL evolution. The prolonged life history of Brook Trout and the onset of canal morphogenesis at swim-up are predicted to have implications for neuromast function at these critical behavioral and ecological transitions.
Sujet(s)
Évolution biologique , Système de la ligne latérale , Truite , Animaux , Système de la ligne latérale/embryologie , Système de la ligne latérale/ultrastructure , Système de la ligne latérale/croissance et développement , Truite/anatomie et histologie , Truite/croissance et développement , Truite/embryologie , Larve/croissance et développement , Crâne/anatomie et histologie , Crâne/croissance et développement , Crâne/embryologie , MorphogenèseRÉSUMÉ
Mounting evidence indicates that the immune response triggered by brain disorders (e.g., brain ischemia and autoimmune encephalomyelitis) occurs not only in the brain, but also in the skull. A key step toward analyzing changes in immune cell populations in both the brain and skull bone marrow after brain damage (e.g., stroke) is to obtain sufficient numbers of high-quality immune cells for downstream analyses. Here, two optimized protocols are provided for isolating immune cells from the brain and skull bone marrow. The advantages of both protocols are reflected in their simplicity, speed, and efficacy in yielding a large quantity of viable immune cells. These cells may be suitable for a range of downstream applications, such as cell sorting, flow cytometry, and transcriptomic analysis. To demonstrate the effectiveness of the protocols, immunophenotyping experiments were performed on stroke brains and normal brain skull bone marrow using flow cytometry analysis, and the results aligned with findings from published studies.
Sujet(s)
Encéphale , Cytométrie en flux , Crâne , Animaux , Souris , Encéphale/cytologie , Encéphale/immunologie , Crâne/cytologie , Crâne/chirurgie , Cytométrie en flux/méthodes , Cellules de la moelle osseuse/cytologie , Cellules de la moelle osseuse/immunologie , Accident vasculaire cérébral/immunologie , Immunophénotypage/méthodesRÉSUMÉ
Biological variation in the mammalian skull is the product of a series of factors including changes in gene expression, developmental timing, and environmental pressures. When considering the diversity of extant mammalian crania, it is important to understand these mechanisms that contribute to cranial growth and in turn, how differences in cranial morphology have been attained. Various researchers, including Dr. Sue Herring, have proposed a variety of mechanisms to explain the process of cranial growth. This work has set the foundation on which modern analysis of craniofacial morphology happens today. This study focused on the analysis of modularity in three mammalian taxa, all of which exhibit facial reduction. Specifically, we examined facial reduction as a morphological phenomenon through the use of two-module and six-module modularity hypotheses. We recorded three-dimensional coordinate data for 55 cranial landmarks that allowed us to analyze differences in cranial shape in these three taxa (primates n = 88, bats n = 64, dogs n = 81). When assessing modularity within the two-module modularity hypothesis specifically, dogs exhibited the lowest levels of modularity, while bats and primates both showed a slightly more modular covariance structure. We further assessed modularity in the same sample using the Goswami six-module model, where again dogs exhibited a low degree of modularity, with bats and primates being more moderate. We then broke the sample into subsets by analyzing each morphotype separately. We hypothesized that the modularity would be more pronounced in the brachycephalic morphotype. Surprisingly, we found that in brachycephalic dogs, normocephalic dogs, brachycephalic primates, and normocephalic primates, there was a moderate degree of modularity. Brachycephalic bats had a low degree of modularity, while normocephalic bats were the most modular group observed in this study. Based on these results, it is evident that facial reduction is a complex and multifaceted phenomenon with unique morphological changes observed in each of the three taxa studied.
Sujet(s)
Chiroptera , Face , Primates , Crâne , Animaux , Chiroptera/anatomie et histologie , Crâne/anatomie et histologie , Chiens/anatomie et histologie , Primates/anatomie et histologie , Face/anatomie et histologie , Évolution biologiqueRÉSUMÉ
Osteoporotic vertebral compression fractures (OVCFs) are the most prevalent fractures among patients with osteoporosis, leading to severe pain, deformities, and even death. This study explored the use of ectopic embryonic calvaria derived mesenchymal stem cells (EE-cMSCs), which are known for their superior differentiation and proliferation capabilities, as a potential treatment for bone regeneration in OVCFs. We evaluated the impact of EE-cMSCs on osteoclastogenesis in a RAW264.7 cell environment, which was induced by the receptor activator of nuclear factor kappa-beta ligand (RANKL), using cytochemical staining and quantitative real-time PCR. The osteogenic potential of EE-cMSCs was evaluated under various hydrogel conditions. An osteoporotic vertebral body bone defect model was established by inducing osteoporosis in rats through bilateral ovariectomy and creating defects in their coccygeal vertebral bodies. The effects of EE-cMSCs were examined using micro-computed tomography (µCT) and histology, including immunohistochemical analyses. In vitro, EE-cMSCs inhibited osteoclast differentiation and promoted osteogenesis in a 3D cell culture environment using fibrin hydrogel. Moreover, µCT and histological staining demonstrated increased new bone formation in the group treated with EE-cMSCs and fibrin. Immunostaining showed reduced osteoclast activity and bone resorption, alongside increased angiogenesis. Thus, EE-cMSCs can effectively promote bone regeneration and may represent a promising therapeutic approach for treating OVCFs.
Sujet(s)
Différenciation cellulaire , Modèles animaux de maladie humaine , Cellules souches mésenchymateuses , Ostéogenèse , Ostéoporose , Crâne , Animaux , Cellules souches mésenchymateuses/métabolisme , Cellules souches mésenchymateuses/cytologie , Rats , Crâne/anatomopathologie , Souris , Ostéoporose/anatomopathologie , Ostéoporose/métabolisme , Ostéoporose/thérapie , Femelle , Cellules RAW 264.7 , Ostéoclastes/métabolisme , Régénération osseuse , Rat Sprague-Dawley , Transplantation de cellules souches mésenchymateuses/méthodes , Corps vertébral/métabolisme , Microtomographie aux rayons X , Fractures ostéoporotiques/thérapie , Fractures ostéoporotiques/métabolisme , Fractures ostéoporotiques/anatomopathologieRÉSUMÉ
Sahelanthropus tchadensis has raised much debate since its initial discovery in Chad in 2001, given its controversial classification as the earliest representative of the hominin lineage. This debate extends beyond the phylogenetic position of the species, and includes several aspects of its habitual behavior, especially in what regards its locomotion. The combination of ancestral and derived traits observed in the fossils associated with the species has been used to defend different hypotheses related to its relationship to hominins. Here, the cranial morphology of Sahelanthropus tchadensis was assessed through 16 linear craniometric measurements, and compared to great apes and hominins through Principal Component Analysis based on size and shape and shape information alone. The results show that S. tchadensis share stronger morphological affinities with hominins than with apes for both the analysis that include size information and the one that evaluates shape alone. Since TM 266-01-060-1 shows a strong morphological affinity with the remaining hominins represented in the analysis, our results support the initial interpretations that S. tchadensis represents an early specimen of our lineage or a stem basal lineage more closely related to hominins than to Panini.
Sujet(s)
Céphalométrie , Fossiles , Hominidae , Crâne , Animaux , Hominidae/anatomie et histologie , Hominidae/classification , Fossiles/anatomie et histologie , Crâne/anatomie et histologie , Analyse en composantes principales , PhylogenèseRÉSUMÉ
The research was designed to use computed tomography (CT) with 3D-CT reconstruction imaging techniques and the various anatomical sections-plana transversalia, frontalis, and dorsalia-to describe the anatomical architecture of the Zebu cattle head. Our study used nine mature heads. The CT bone window created detailed images of cranial bones, mandibles, teeth, and hyoid bones. All of the head cavities were evaluated, including the cranial, orbital, oral, auricular, and nasal cavities with their paranasal and conchal sinuses. The septum nasi, attached to the vomer and maxillary bones, did not reach the nasal cavity floor caudally at the level of the second premolar teeth, resulting in a single median channel from the choanae to the nasopharynx. The positions, boundaries, and connections of the paranasal sinuses were clearly identified. There were four nasal conchal sinuses (that were named the dorsal, middle, ethmoidal, and ventral) and five paranasal sinuses that were described as the following: sinus frontalis, maxillaris, palatinorum, and lacrimalis, as defined in the different anatomical sections and computed tomographic images. The complicated sinus frontalis caused the pneumatization of all bones that surrounded the cranial cavity, with the exception of the ethmoidal and body of basisphenoid bones. The sinus maxillaris was connected to the sinus lacrimalis and palatinorum through the maxillolacrimal and palatomaxillary openings, and to the middle nasal meatus through the nasomaxillary opening. Our findings provide a detailed anatomical knowledge for disease diagnosis to internal medicine veterinarians and surgeons by offering a comprehensive atlas of the Zebu cattle anatomy.