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Current Topics in Developmental Biology 2015The skull vault is a complex, exquisitely patterned structure that plays a variety of key roles in vertebrate life, ranging from the acquisition of food to the support... (Review)
Review
The skull vault is a complex, exquisitely patterned structure that plays a variety of key roles in vertebrate life, ranging from the acquisition of food to the support of the sense organs for hearing, smell, sight, and taste. During its development, it must meet the dual challenges of protecting the brain and accommodating its growth. The bones and sutures of the skull vault are derived from cranial neural crest and head mesoderm. The frontal and parietal bones develop from osteogenic rudiments in the supraorbital ridge. The coronal suture develops from a group of Shh-responsive cells in the head mesoderm that are collocated, with the osteogenic precursors, in the supraorbital ridge. The osteogenic rudiments and the prospective coronal suture expand apically by cell migration. A number of congenital disorders affect the skull vault. Prominent among these is craniosynostosis, the fusion of the bones at the sutures. Analysis of the pathophysiology underling craniosynostosis has identified a variety of cellular mechanisms, mediated by a range of signaling pathways and effector transcription factors. These cellular mechanisms include loss of boundary integrity, altered sutural cell specification in embryos, and loss of a suture stem cell population in adults. Future work making use of genome-wide transcriptomic approaches will address the deep structure of regulatory interactions and cellular processes that unify these seemingly diverse mechanisms.
Topics: Animals; Cranial Sutures; Craniosynostoses; Gene Expression Regulation, Developmental; Humans; Mesoderm; Morphogenesis; Neural Crest; Signal Transduction; Skull
PubMed: 26589924
DOI: 10.1016/bs.ctdb.2015.07.004 -
Journal of Stomatology, Oral and... Feb 2023Oligodontia is a developmental dental anomaly defined by the absence of 6 or more permanent teeth, excluding the third molars. We performed a review with a systematic... (Review)
Review
Oligodontia is a developmental dental anomaly defined by the absence of 6 or more permanent teeth, excluding the third molars. We performed a review with a systematic approach and proposed a guideline for the choice of the bone augmentation surgery. The different bone augmentation technique terms were searched in the PubMed and Science Direct database. Clinical studies were eligible if they reported on pre-implant surgery in patients with oligodontia. The database search yielded 400 studies after duplicates removed. Thirty studies were finally included, involving 410 patients. Sixty-three sinus lifts were performed in 37 patients with no failure. Thirteen out of 33 patients with iliac bone transplantation and two out of 24 with parietal bone transplantation had resorption, one out of 4 patients who received allogeneic bone block had complete failure. Seventy-eight patients underwent guided bone regeneration, none had bone loss. No failure was found with the alveolar distraction osteogenesis technique. Four out of thirteen patients developed permanent hypoesthesia after inferior alveolar nerve transposition. The cumulative implant survival rate was 94.4% after bone augmentation procedures. Extensive edentulous areas should be grafted with parietal bone, as iliac grafts present a greater risk of resorption. Smaller edentulous areas should be treated by endobuccal harvesting or guided bone regeneration. Osteogenesis distraction and nerve transposition are effective surgeries for medium-to-large mandibular edentulous spaces. The implant survival rate is not significantly different between implants placed in grafted and nongrafted bone, the appropriate choice of bone augmentation technique can reduce the risk of peri‑implant bone resorption.
Topics: Humans; Dental Implantation, Endosseous; Dental Implants; Alveolar Ridge Augmentation; Bone Transplantation; Mouth, Edentulous
PubMed: 36567052
DOI: 10.1016/j.jormas.2022.101370 -
Developmental Biology Sep 2023The skull is a fundamental bone that protects the development of brain and consists of several bony elements, such as the frontal and parietal bones. Frontal bone...
The skull is a fundamental bone that protects the development of brain and consists of several bony elements, such as the frontal and parietal bones. Frontal bone exhibited superior in osteogenic potential and regeneration of cranial defects compared to parietal bone. However, how this regional difference is regulated remains largely unknown. In this study, we identified an Ap-2β transcriptional factor with a higher expression in frontal bone, but its molecular function in osteoblasts needs to be elucidated. We found that Ap-2β knockdown in preosteoblasts leads to reduced proliferation, increased cell death and impaired differentiation. Through RNA-seq analysis, we found that Ap-2β influences multiple signaling pathways including the Wnt pathway, and overexpression of Ap-2β showed increased nuclear β-catenin and its target genes expressions in osteoblasts. Pharmacological activation of Wnt/β-catenin signaling using LiCl treatment cannot rescue the reduced luciferase activities of the β-catenin/TCF/LEF reporter in Ap-2β knockdown preosteoblasts. Besides, transient expression of Ap-2β via the lentivirus system could sufficiently rescue the inferior osteogenic potential in parietal osteoblasts, while Ap-2β knockdown in frontal osteoblasts resulted in reduced osteoblast activity, reduced active β-catenin and target genes expressions. Taken together, our data demonstrated that Ap-2β modulates osteoblast proliferation and differentiation through the regulation of Wnt/β-catenin signaling pathway and plays an important role in regulating regional osteogenic potential in frontal and parietal bone.
Topics: Wnt Signaling Pathway; beta Catenin; Transcription Factors; Cell Differentiation; Skull; Osteogenesis; Osteoblasts; Cells, Cultured
PubMed: 37355029
DOI: 10.1016/j.ydbio.2023.06.015 -
Revista Brasileira de Ortopedia Jun 2022To evaluate the systemic effect of latex on bone neoformation and mineralization in rats. For that, the latex was first collected, and its composition was...
To evaluate the systemic effect of latex on bone neoformation and mineralization in rats. For that, the latex was first collected, and its composition was analyzed. A total of 30 male Wistar rats were used, which were simultaneously submitted to two surgical procedures: extraction of an incisor and creation of a defect with 2 mm in diameter in the parietal bone. The rats were divided into two groups: systemic control (SC) systemic latex (SX) which were administered, orally and daily, 1.5 mL of water or a solution containing 50% of water and 50% of latex by gavage, respectively. After 15 days of the treatment, the animals were euthanized and their samples were collected. The results were statistically analyzed, and the level of significance was set at 0.05. We showed that latex contained calcium. The oral and daily administration of the latex for 15 days increased the contents of calcium and phosphorus in the basal bone and newly-formed bone in the mandibular alveolus of rats. The present was a pioneer study demonstrating the potential of latex in increasing bone mineralization. Our results may aid in the conception and development of a natural drug.
PubMed: 35785126
DOI: 10.1055/s-0041-1741020 -
Legal Medicine (Tokyo, Japan) Mar 2022Anatomical or morphological variations of the skull bones usually do not attract much attention among forensic pathologists. However, these variations can sometimes be...
Anatomical or morphological variations of the skull bones usually do not attract much attention among forensic pathologists. However, these variations can sometimes be an important marker in forensic identification of a person or represent a missing piece when solving a cranial trauma puzzle. In this article, we were interested in peculiar presentation of the thinning of both parietal bones (biparietal osteodystrophy). The course and etiology of this condition still remain unknown. In three autopsy cases with biparietal osteodystrophy (three females aged 95, 90 and 83) and no head trauma, we used conventional (CT) and microcomputed tomography (micro-CT) imaging of the skull and parietal bone specimens containing normal bone, transitional zone and thinned bone with osteodystrophy. CT images demonstrated an oval-shaped resorptive parietal bone depression with smooth contours, without marginal osteosclerotic changes or involvement of cranial sutures. In the transitional zone, micro-CT scans showed a decrease in total bone thickness and the thickness of diplöe, while inner and outer tables showed increased porosity. At the site of maximal thinness of the parietal bone, inner and outer tables fused and formed a thin layer of cortical bone. Skull thinning appeared due to the reduced thickness of diplöe, leading to egg-shell thinning in the central area of the parietal bones. A forensic pathologist should be familiar with this benign condition in order not to confuse it with resorptive bone diseases.
Topics: Autopsy; Cranial Sutures; Female; Humans; Parietal Bone; Skull; X-Ray Microtomography
PubMed: 35066334
DOI: 10.1016/j.legalmed.2022.102025 -
Animals : An Open Access Journal From... Jul 2023The present investigation endeavours to discern dental and non-dental pathologies affecting cranial structures of raccoon dogs, while focusing on cases of periodontitis....
The present investigation endeavours to discern dental and non-dental pathologies affecting cranial structures of raccoon dogs, while focusing on cases of periodontitis. Furthermore, the study aims to conduct a comparative analysis based on sex and the nature of the pathologies encountered. The number of investigated skulls amounted to 126, including 76 males and 50 females. The predominant pathology identified was hypodontia, which accounted for 26.7% of males and 20% of females. Notably, the majority of hypodontia cases involved the absence of the mandibular third molar. Another noteworthy pathology was various stages of periodontitis, with rates ranging from 21.3% in males to 8% in females. Other pathologies, like tooth fractures and abrasion, were significantly less encountered. Excessive bone formation was relatively abundant and localized in specific areas-the parietal bone and the occipital regions. This tendency was observed in 8% of male cases and 6% of females. We found that the total number of dental and skull-bone pathologies is significantly more common in males than in females ( = 0.003). Additionally, the total number of various cases of periodontitis is more common in males too ( = 0.04).
PubMed: 37570246
DOI: 10.3390/ani13152437 -
The Journal of Craniofacial Surgery Sep 2022Unilateral coronal craniosynostosis (UCS) is a congenital disorder resulting from the premature suture fusion, leading to complex primary and compensatory morphologic...
BACKGROUND
Unilateral coronal craniosynostosis (UCS) is a congenital disorder resulting from the premature suture fusion, leading to complex primary and compensatory morphologic changes in the shape of not only the calvarium and but also into the skull base. This deformity typically requires surgery to correct the shape of the skull and prevent neurologic sequelae, including increased intracranial pressure, sensory deficits, and cognitive impairment.
METHODS
The present multicenter study sought to reverse-engineer the bone dysmorphogenesis seen in non-syndromic UCS using a geometric morphometric approach. Computed tomography scans for 26 non-syndromic UCS patients were converted to three-dimensional mesh models. Two hundred thirty-six unique anatomical landmarks and semi-landmarked curves were then plotted on each model, creating wireframe representations of the Patients' skulls.
RESULTS
Generalized Procrustes superimposition, Principal Component Analysis, and heatmaps identified significant superior displacement of the ipsilateral orbit ("harlequin" eye deformity), anterior displacement of the ear ipsilateral to the fused coronal suture, acute deviation of midline skull base structures ipsilateral to the fused coronal suture and flattening of the parietal bone and associated failure to expand superiorly.
CONCLUSIONS
The described technique illustrates the impact of premature coronal suture fusion on the development of the entire skull and proposes how bone dysmorphology contributes to the Patients' neurologic sequelae. By bridging novel basic science methodologies with clinical research, the present study quantitatively describes craniofacial development and bone dysmorphogenesis.
Topics: Cranial Sutures; Craniosynostoses; Humans; Infant; Orbit; Skull; Skull Base; Tomography, X-Ray Computed
PubMed: 35013073
DOI: 10.1097/SCS.0000000000008464 -
Journal of Orthopaedic Surgery and... Feb 2020Ketamine is a widely used anesthetic in experimental medicine. We have also used ketamine for surgical interventions and imaging in rats and found significantly impaired...
BACKGROUND
Ketamine is a widely used anesthetic in experimental medicine. We have also used ketamine for surgical interventions and imaging in rats and found significantly impaired ossification between identically performed experiments, which only differed in the number of anesthetic events. In order to investigate this phenomenon, we estimated the absorbed ionizing radiation and also studied whether ketamine administration has disadvantageous effect on bone cell viability.
METHODS
Spongious bone chips and parietal bone disks were harvested from rats. Explants were incubated in stem cell media containing 0.02, 0.2 and 2 mM ketamine. After 3 days of incubation, tetrazolium-based spectrophotometric assay was performed to measure cell viability. Size-specific dose estimation was used to calculate ionizing radiation of computed tomography imaging.
RESULTS
We found that ketamine supplementation with 0.2 mM slightly decreased cell viability, while 2 mM caused significant reduction both in the spongious and cortical explants. The cumulative ionizing radiation was found to be negligible compared to irradiation dosages used to impair ossification.
CONCLUSIONS
We conclude that multiple ketamine administration was responsible for the diminished regenerative potential of bone tissue in the present experimental setup. For this reason, we suggest that ketamine anesthesia should be avoided in studies investigating bone regeneration.
Topics: Analgesics; Animals; Cell Survival; Cells, Cultured; Dose-Response Relationship, Drug; Ketamine; Male; Parietal Bone; Rats; Rats, Wistar; Wound Healing
PubMed: 32046745
DOI: 10.1186/s13018-020-1579-x -
Journal of Biomechanical Engineering Feb 2017This review was prepared for the American Society of Mechanical Engineers Lissner Medal. It specifically discusses research performed in the Orthopaedic Biomechanics... (Review)
Review
This review was prepared for the American Society of Mechanical Engineers Lissner Medal. It specifically discusses research performed in the Orthopaedic Biomechanics Laboratories on pediatric cranial bone mechanics and patterns of fracture in collaboration with the Forensic Anthropology Laboratory at Michigan State University. Cranial fractures are often an important element seen by forensic anthropologists during the investigation of pediatric trauma cases litigated in courts. While forensic anthropologists and forensic biomechanists are often called on to testify in these cases, there is little basic science developed in support of their testimony. The following is a review of studies conducted in the above laboratories and supported by the National Institute of Justice to begin an understanding of the mechanics and patterns of pediatric cranial bone fracture. With the lack of human pediatric specimens, the studies utilize an immature porcine model. Because much case evidence involves cranial bone fracture, the studies described below focus on determining input loading based on the resultant bone fracture pattern. The studies involve impact to the parietal bone, the most often fractured cranial bone, and begin with experiments on entrapped heads, progressing to those involving free-falling heads. The studies involve head drops onto different types and shapes of interfaces with variations of impact energy. The studies show linear fractures initiating from sutural boundaries, away from the impact site, for flat surface impacts, in contrast to depressed fractures for more focal impacts. The results have been incorporated into a "Fracture Printing Interface (FPI)," using machine learning and pattern recognition algorithms. The interface has been used to help interpret mechanisms of injury in pediatric death cases collected from medical examiner offices. The ultimate aim of this program of study is to develop a "Human Fracture Printing Interface" that can be used by forensic investigators in determining mechanisms of pediatric cranial bone fracture.
Topics: Animals; Animals, Newborn; Child; Child Abuse; Child, Preschool; Compressive Strength; Computer Simulation; Elastic Modulus; Female; Forensic Medicine; Humans; Infant; Infant, Newborn; Male; Models, Biological; Parietal Bone; Skull Fractures; Stress, Mechanical; Swine; Wounds, Nonpenetrating
PubMed: 27537363
DOI: 10.1115/1.4034430 -
Ultrasound in Medicine & Biology Mar 2021We investigate guided (Lamb) waves in a human cadaver skull through experiments and computational simulations. Ultrasonic wedge transducers and scanning laser Doppler...
We investigate guided (Lamb) waves in a human cadaver skull through experiments and computational simulations. Ultrasonic wedge transducers and scanning laser Doppler vibrometry are used respectively to excite and measure Lamb waves propagating in the cranial bone of a degassed skull. Measurements are performed over a section of the parietal bone and temporal bone spanning the squamous suture. The experimental data are analyzed for the identification of wave modes and the characterization of dispersion properties. In the parietal bone, for instance, the A wave mode is excited between 200 and 600 kHz, and higher-order Lamb waves are excited from 1 to 1.8 MHz. From the experimental dispersion curves and average thickness extracted from the skull computed tomography scan, we estimate average isotropic material properties that capture the essential dispersion characteristics using a semi-analytical finite-element model. We also explore the leaky and non-leaky wave behavior of the degassed skull with water loading in the cranial cavity. Successful excitation of leaky Lamb waves is confirmed (for higher-order wave modes with phase velocity faster than the speed of sound in water) from 500 kHz to 1.5 MHz, which may find applications in imaging and therapeutics at the brain periphery or skull-brain interface (e.g., for metastases). The non-leaky A Lamb wave mode propagates between 200 and 600 kHz, with or without fluid loading, for potential use in skull-related diagnostics and imaging (e.g., for sutures).
Topics: Cadaver; Computer Simulation; Finite Element Analysis; Humans; Skull; Ultrasonic Waves
PubMed: 33358510
DOI: 10.1016/j.ultrasmedbio.2020.11.019