micro-CT Scanning Research Articles

Development of A Micro-CT Scanner with Dual-Energy Option and Endovascular Contrast Agent Administration Protocol for Fetal and Neonatal Virtual Autopsy.

The rate of parental consent for fetal and perinatal autopsy is decreasing, whereas parents are more likely to agree to virtual autopsy by non-invasive imaging methods. Fetal and perinatal virtual autopsy needs high-resolution and good soft-tissue contrast for investigation of the cause of death and underlying trauma or pathology in fetuses and stillborn infants. This is offered by micro-computed tomography (CT), as opposed to the limited resolution provided by clinical CT scanners, and this is one of the most promising tools for non-invasive perinatal postmortem imaging. We developed and optimized a micro-CT scanner with a dual-energy imaging option. It is dedicated to post-mortem CT angiography and virtual autopsy of fetuses and stillborn infants in that the chamber can be cooled down to around 5 °C; this increases tissue rigidity and slows decomposition of the native specimen. This, together with the dedicated gantry-based architecture, attempts to reduce potential motion artifacts. The developed methodology is based on prior endovascular injection of a BaSO4-based contrast agent. We explain the design choices and considerations for this scanner prototype. We give details of the treatment of the optimization of the dual-energy and virtual mono-energetic imaging option that has been based on minimizing noise propagation and maximizing the contrast-to-noise ratio for vascular features. We demonstrate the scanner capabilities with proof-of-concept experiments on phantoms and stillborn piglets.

Morphological examination of abdominal vertebral bodies from grass carp using high-resolution micro-CT scans.

The vertebral column, a defining trait of all vertebrates, is organized as a concatenated chain of vertebrae, and therefore its support to the body depends on individual vertebral morphology. Consequently, studying the morphology of the vertebral centrum is of anatomical and clinical importance. Grass carp (GC) is a member of the infraclass Teleostei (teleost fish), which accounts for the majority of all vertebrate species; thus, its vertebral anatomical structure can help us understand vertebrate development and vertebral morphology. In this study, we have investigated the morphology and symmetry of the grass carp vertebral centrum using high-resolution micro-CT scans. To this end, three abdominal vertebrae (V9, V10, & V11) from eight grass carp were micro-CT scanned and then segmented using Dragonfly (ORS Inc.). Grass carp vertebral centrum conformed to the basic teleost pattern and demonstrated an amphicoelous shape (biconcave hourglass). The centrum's cranial endplate was smaller, less circular, and shallower compared to the caudal endplate. While the vertebral centrum demonstrated bilateral symmetry along the sagittal plane (left/right), the centrum focus was shifted dorsally and cranially, breaking dorsoventral and craniocaudal symmetry. The sum of these findings implies that the caudal aspect of grass carp vertebral centrum is bigger and more robust. Currently, we have no information whether this is due to nature, for example, differences in gene expression, or nurture, for example, environmental effect. As the vertebral parapophyses and spinous processes are slanted caudally, the direction of muscle action during swimming may create a gradient of stresses from cranial to caudal, resulting in a more robust caudal aspect of the vertebral centrum. Expanding our study to include additional quadrupedal and bipedal (i.e., human) vertebrae, as well as testing if these morphological aspects of the vertebrae are indeed plastic and can be affected by environmental factors (i.e., temperature or other stressors) may help answer this question.

A novel porous titanium with engineered surface for bone defect repair in load-bearing position.

Porous titanium exhibits low elastic modulus and porous structure is thought to be a promising implant in bone defect repair. However, the bioinert and low mechanical strength of porous titanium have limited its clinical application, especially in load-bearing bone defect repair. Our previous study has reported an infiltration casting and acid corrosion (IC-AC) method to fabricate a novel porous titanium (pTi) with 40% porosity and 0.4 mm pore diameter, which exerts mechanical property matching with cortical bone and interconnected channels. In this study, we introduced a nanoporous coating and incorporated an osteogenic element strontium (Sr) on the surface of porous titanium (named as Sr-micro arch oxidation [MAO]) to improve the osteogenic ability of the pTi by MAO. Better biocompatibility of Sr-MAO was verified by cell adhesion experiment and cell counting kit-8 (CCK-8) test. The in vitro osteogenic-related tests such as immunofluorescence staining, alkaline phosphatase staining and real-time polymerase chain reaction (RT-PCR) demonstrated better osteogenic ability of Sr-MAO. Femoral bone defect repair model was employed to evaluate the osseointegration of samples in vivo. Results of micro-CT scanning, sequential fluorochrome labeling and Van Gieson staining suggested that Sr-MAO showed better in vivo osteogenic ability than other groups. Taking results of both in vitro and in vivo experiment together, this study indicated the Sr-MAO porous titanium could be a promising implant load-bearing bone defect.

The Effect of Gravity on Marginal Integrity of Different Flowable Bulk-Fill Resin Composites.

Background and Objectives: The aim of this quantitative research was to investigate the effect of gravitational forces on the marginal integrity of different bulk-fill composites by micro-CT imaging. Materials and Methods: Fifty caries-free human third molars extracted for prophylactic purposes were used in this study. Each tooth was prepared with two proximal box cavities, with dimensions of 3 mm × 3 mm × 5 mm. Five distinct groups, each comprising 20 cavities, thus totaling 100 cavities for this study: (1, Group CON): Clearfil Majesty Flow + Clearfil Majesty Esthetic (as the control); (2, Group FBR): Filtek Bulk-fill Flowable Restorative + Clearfil Majesty Esthetic; (3, Group XTB): Voco Extrabase + Clearfil Majesty Esthetic; (4, Group SDR): SDR + Clearfil Majesty Esthetic; and (5, Group SNC): Sonicfill. When restoring the mesial cavities, the occlusal surfaces of the teeth in the mold were positioned upwards, counteracting the force of gravity. In contrast, for the restoration of the distal cavities, the occlusal surfaces were aligned downwards, to be parallel with the gravitational pull. After restorative procedures, each tooth was treated with 5000 thermal cycles. A solution of ammoniacal silver nitrate (AgNO3) was employed as a tracing agent. The micro-CT scans were conducted and the total volume of silver nitrate and the total volume of restorations within the relevant region of interest were calculated in "mm3" with software. Two-way ANOVA and Tukey tests were performed at a significance level of p = 0.05 with Graphpad Prism v 8.2.1 software. Results: Both gravity effect and interaction showed no statistical differences (p > 0.05). Statistically significant differences were observed in the restorative materials (p < 0.05). Conclusions: Gravitational forces do not emerge as a major factor affecting the marginal integrity of flowable bulk-fill composites in class II restorations. The chemical composition of the composites plays a more crucial role, with the XTB composite showing higher microleakage ratios compared to the others.

Comment on “Bacterial bioerosion of bones is a post-skeletonisation phenomenon and appears contingent on soil burial” [Quat. Int. 660 (2023) 75–83]

Histotaphonomic analysis, through thin section microscopy, SEM and micro-CT scanning, has become an increasingly popular approach for archaeologists in recent years. The method relies on assessing the character of degradation in bone microstructure, placing particular importance on the degree and nature of bacterial bioerosion. However, there remains considerable disagreement about the origins and timing of bacterial bioerosion and this has major ramifications for the interpretative potential of the approach. Turner-Walker et al. (2023) p resent a firm case for the origins of bacteria being exclusively exogenous (from the soil) with bioerosion occurring only after skeletonisation. This scenario means that information gained from analysis of histotaphonomy relates entirely to the nature of the burial environment and its suitability for collagenolytic bacteria to thrive and thus provides very little useful information about human behaviour and mortuary practice. This contrasts with the common position that the origins of bacteria can be enteric (from the gut) and can effect bioerosion during putrefaction in the early post-mortem phase, thus potentially informing on mortuary practice.In this response, we present the alternative view to Turner-Walker et al. (2023) and demonstrate strong and wide-ranging evidence for bacteria from the gut microbiome to have the potential to cause bioerosion. A review of previous studies is used to evidence the impact of mortuary practice on variable microstructural preservation. We counter some of Turner-Walker et al.‘s key lines of evidence and present alternative, evidence-based explanations. Importantly, we acknowledge that the origins of bacteria are not always enteric and that current interpretations that only consider bacteria as either enteric or exogenous cannot account for the variability seen in the archaeological record.

The effect of root canal preparation tapers on planktonic bacteria and biofilm reduction in the apical third: A correlative microtomography and microbiological laboratory study.

To evaluate the influence of different preparation tapers on the reduction in planktonic bacteria and biofilms of Enterococcus faecalis and Candida albicans in the apical third (4 mm) of the mesial roots of mandibular molars, correlating decontamination with canal shape. After microtomography analysis for morphological standardization of the canals, 48 mandibular molar roots, each containing two canals (96 canals), were contaminated with E. faecalis and C. albicans and divided into four groups (n = 11) for canal instrumentation using ProDesign Logic 2 files with different tapers G (.03): # 25.03; G (.04): # 25.04; G (.05): # 25.05; and G (.06): # 25.06 and irrigation with 2.5% sodium hypochlorite. Four roots were examined under a scanning electron microscope (SEM) to qualitatively assess biofilm formation. Eight roots were used as the negative control group (samples were not contaminated). Bacteriological samples were taken exclusively from the apical third of the roots before and after chemical-mechanical preparation and bacterial counts were determined (CFU/mL). The final micro-CT scan was used to quantify the volume variation and unprepared canal area in the apical third. Statistical analysis was performed using the Kruskal-Wallis, Student-Newman-Keuls and Wilcoxon tests for analysis of microbiological data. anova and the Tukey or Games-Howell test were used for analysis of micro-CT data and Spearman's test for correlations (α = 5%). All groups showed a significant reduction in bacteria (p < .05), with no statistically significant difference between groups. There was no significant difference in per cent volume increase between groups. The unprepared area (Δ%) was affected by the file used (p = .026) and was significantly lower for G (.06) compared to G (.03). There was no statistically significant correlation among bacterial reduction, volume and unprepared area (p > .05). The different preparation tapers influenced root canal shaping in the apical third but did not improve decontamination in this region.

Unpacking the terminology used in human cochlear dimension methodologies

Many definitions of the dimensions of cochlear measurements are described in the literature. However, these terminologies are typically not standardised or vary among disciplines. Confusion of the defined parameters may lead to ambiguity in the derived dimensions. Inconsistent terminology may, therefore, contribute to the variations reported in cochlear morphology. This article proposes using a standard set of terminology, including its associated landmarks and measurements, to describe the shape and dimensions of the human cochlea. To provide a basis for comparison for the dimensional description of ambiguous terms in the literature and to supplement existing data where terms are unique, micro-CT (μCT) scans of thirty temporal bones were subjected to landmarking and measuring according to the terminology standard. The results confirm that methodological techniques and definitions of cochlear measurements may affect the quantification of dimensions that describe cochlear morphology and may, therefore, introduce variations when reporting these measurements. Histology and μCT images, for example, could provide a more accurate and comprehensive measure of cochlear dimensions than measurements on casts.

Effect of Freeze–Thaw Cycles on Microstructure and Hydraulic Characteristics of Claystone: A Case Study of Slope Stability from Open-Pit Mines in Wet Regions

The action of freeze–thaw (F–T) cycles of claystone exerts a profound impact on the slope stability of open-pit mines in water-rich regions. Microstructural changes are observed as a crucial factor in determining the hydraulic characteristics and mechanical behaviors of claystone. The present work integrates a micro-X-ray computed tomography (Micro-CT) scanner, equipped with image processing and three-dimensional (3D) reconstruction capabilities, employed to observe the microstructure of claystone under varying numbers of F–T cycles (0, 10, 20, 30, and 50). Furthermore, seepage numerical simulations based on Micro-CT measurements are conducted to evaluate the hydraulic characteristics. Through meticulous microscopic observation and mechanical analysis, the damage mechanism induced by F–T cycles is revealed and the evolutionary characteristics are analyzed. The two-dimensional (2D) images of 3D reconstructed models unveil the gradual initiation propagation and coalescence of an intricate fissuring network in claystone during the F–T cycles. As the number of F–T cycles increases from 0 to 50, the 3D porosity exhibits exponential growth. Additionally, the influence of F–T cycles substantially enhances the connectivity of fissures. The seepage numerical simulations demonstrate that the evolutionary progression of fissures substantially augments the number of flow paths and enhances permeability. The increase in permeability follows an exponential trend, reflecting the distribution and evolution of fissures under F–T cycles. The impact on permeability arises from a combination of micromechanical properties and the microstructure of claystones. The present research tries to elucidate the microscopic evolution of fissures and their corresponding hydraulic properties in water-saturated claystone, offering significant insights for investigating the slope stability of open-pit mines in regions.

A polylactic acid/hydroxyapatite/scholzite composite scaffold for promoting healing of osteoporotic bone defects in rats

To investigate the release kinetics of Zn2+ from nZCP-loaded polylactic acid/hydroxyapatite (PLA/HA) composite scaffold (PHZ) and determine the optimal nZCP content in the scaffold. The particle size of nZCP was measured by DLS measurement, and PXRD, FTIR, and SEM were used to characterize the scaffolds and nZCP distribution; EDS was used to analyze element composition of the scaffold. Compression strength of the scaffold was determined, and ion release profile was investigated using ICP-MS. The biocompatibility of the materials was evaluated by CCK-8 assay and dead/alive staining of rat bone marrow stem cells (BMSCs) incubated with their aqueous extracts. ALP staining, alizarin red staining, RT-qPCR, and Western blotting were used to assess the osteogenic potential of the treated cells. In a rat model of bilateral ovariectomy (OVX) with femoral condylar bone defect, PHZ-1, PHZ-2, PHZ-3 or PLA/HA scaffold was implanted into the bone defect, and bone repair was observed using a microCT scanner and histological staining at 6 and 12 weeks. DLS, PXRD, SEM, FTIR, and EDS confirmed successful synthesis of 10-nm ZCP and efficient nZCP loading in the scaffold. PHZ-2 and PHZ-3 had significantly greater compression strength than PLA/HA. ICP-MS showed that Zn2+ release from PHZ-1, PHZ-2 and PHZ-3 were all optimal for promoting osteogenesis. In rat BMSCs, all the 4 scaffolds showed good biocompatibility, and their extracts enhanced ALP activity and extracellular matrix mineralization and promoted expressions of ALP, RUNX2, and OCN in the cells. In the rat models, nZCP in the implants improved bone graft integration at 6 weeks, and PHZ-2 and PHZ-3 more effectively induced new bone formation at 12 weeks (P < 0.05). PHZ scaffold is capable of stable Zn2+ release to promote osteoporotic bone defect healing, and PHZ-2 and PHZ-3 scaffolds with nZCP mass fraction of 4.5%-7.5% have better osteogenic activity.

Bioarchaeological investigation of individuals with suspected multibacillary leprosy from the mediaeval leprosarium of St Mary Magdalen, Winchester, Hampshire, UK.

Introduction. We have examined four burials from the St Mary Magdalen mediaeval leprosarium cemetery in Winchester, Hampshire, UK. One (Sk.8) was a male child, two (Sk.45 and Sk.52) were adolescent females and the fourth (Sk.512) was an adult male. The cemetery was in use between the 10th and 12th centuries. All showed skeletal lesions of leprosy. Additionally, one of the two females (Sk.45) had lesions suggestive of multi-cystic tuberculosis and the second (Sk.52) of leprogenic odontodysplasia (LO), a rare malformation of the roots of the permanent maxillary incisors.Gap statement. Relatively little is known of the manifestations of lepromatous leprosy (LL) in younger individuals from the archaeological record.Aims and Methodology. To address this, we have used ancient DNA testing and osteological examination of the individuals, supplemented with X-ray and microcomputed tomography (micro-CT) scan as necessary to assess the disease status.Results and Conclusions. The presence of Mycobacterium leprae DNA was confirmed in both females, and genotyping showed SNP type 3I-1 strains but with a clear genotypic variation. We could not confirm Mycobacterium tuberculosis complex DNA in the female individual SK.45. High levels of M. leprae DNA were found within the pulp cavities of four maxillary teeth from the male child (Sk.8) with LO, consistent with the theory that the replication of M. leprae in alveolar bone may interfere with root formation at key stages of development. We report our biomolecular findings in these individuals and review the evidence this site has contributed to our knowledge of mediaeval leprosy.

Cichoric acid targets RANKL to inhibit osteoclastogenesis and prevent ovariectomy-induced bone loss.

Osteoporosis, a systemic metabolic bone disease, is characterized by the decline of bone mass and quality due to excessive osteoclast activity. Currently, drug-targeting osteoclasts show promising therapy for osteoporosis. In this study, we investigated the effect of cichoric acid (CA) on receptor activator of nuclear kappa-B ligand (RANKL)-induced osteoclastogenesis and the bone loss induced by ovariectomy in mice. Molecular docking technologies were employed to examine the interaction between CA and RANKL. CCK8 assay was used to evaluate the cell viability under CA treatment. TRAcP staining, podosome belt staining, and bone resorption assays were used to test the effect of CA on osteoclastogenesis and osteoclast function. Further, an OVX-induced osteoporosis mice model was employed to identify the effect of CA on bone loss using micro-CT scanning and histological examination. To investigate underlying mechanisms, network pharmacology was applied to predict the downstream signaling pathways, which were verified by Western blot and immunofluorescence staining. The molecular docking analysis revealed that CA exhibited a specific binding affinity to RANKL, engaging multiple binding sites. CA inhibited RANKL-induced osteoclastogenesis and bone resorption without cytotoxic effects. Mechanistically, CA suppressed RANKL-induced intracellular reactive oxygen species, nuclear factor-kappa B, and mitogen-activated protein kinase pathways, followed by abrogated nuclear factor activated T-cells 1 activity. Consistent with this finding, CA attenuated post-ovariectomy-induced osteoporosis by ameliorating osteoclastogenesis. CA inhibited osteoclast activity and bone loss by targeting RANKL. CA might represent a promising candidate for treating osteoclast-related diseases, such as osteoporosis.

Are Artificial Intelligence-Assisted Three-Dimensional Histological Reconstructions Reliable for the Assessment of Trabecular Microarchitecture?

Objectives: This study aimed to create a three-dimensional histological reconstruction through the AI-assisted classification of tissues and the alignment of serial sections. The secondary aim was to evaluate if the novel technique for histological reconstruction accurately replicated the trabecular microarchitecture of bone. This was performed by conducting micromorphometric measurements on the reconstruction and comparing the results obtained with those of microCT reconstructions. Methods: A bone biopsy sample was harvested upon re-entry following sinus floor augmentation. Following microCT scanning and histological processing, a modified version of the U-Net architecture was trained to categorize tissues on the sections. Detector-free local feature matching with transformers was used to create the histological reconstruction. The micromorphometric parameters were calculated using Bruker's CTAn software (version 1.18.8.0, Bruker, Kontich, Belgium) for both histological and microCT datasets. Results: Correlation coefficients calculated between the micromorphometric parameters measured on the microCT and histological reconstruction suggest a strong linear relationship between the two with p-values of 0.777, 0.717, 0.705, 0.666, and 0.687 for BV/TV, BS/TV, Tb.Pf Tb.Th, and Tb.Sp, respectively. Bland-Altman and mountain plots suggest good agreement between BV/TV measurements on the two reconstruction methods. Conclusions: This novel method for three-dimensional histological reconstruction provides researchers with a tool that enables the assessment of accurate trabecular microarchitecture and histological information simultaneously.

Trans-scale analysis of 3D braided composites with voids based on micro-CT imaging and unsupervised machine learning

Voids are unavoidable during the manufacturing of 3D braided composites. This study proposes an unsupervised machine learning method combined with micro-computed tomography (micro-CT) scanning and a progressive damage analysis to analyze defects in these composites at a trans-scale level. The method enables the creation of real multiscale models and the determination of the porosity in both the intra-yarn (1.52 %) and inter-yarn (5.04 %) planes. Here, the unsupervised machine learning method is introduced in a trans-scale damage analysis to reduce calculation dimensions and to visualize the clustering data. A user-defined material subroutine (UMAT) is also developed to implement the trans-scale damage model. The experimental validation of the simulation results demonstrates the effective trans-scale damage analysis, showing the predominant pull-shear damage in the yarns, which is primarily located at the interfaces both between the yarns and between the yarns and the matrix. Finally, based on the scanned geometric data the degradation in modulus and strength of 3D braided composites with porosity is studied.

Targeted Overexpression of Claudin 11 in Osteoblasts Increases Trabecular Bone Mass by Stimulating Osteogenesis at the Expense of Adipogenesis in Mice.

Mice lacking Claudin11 (Cldn11) manifest reduced trabecular bone mass. However, the impact of Cldn11 expression in osteoblasts in vivo remains understudied. Herein, we generated osteoblast-specific transgenic (Tg) mice expressing Cldn11 and characterized their skeletal phenotype. Micro-CT analyses of the distal metaphysis of the femur showed a 50% and a 38% increase in trabecular bone mass in Tg male and female mice, respectively, due to a significant increase in trabecular number and a reduction in trabecular separation. Histomorphometry and serum biomarker studies uncovered that increased trabecular bone mass in Cldn11 Tg mice was the consequence of enhanced bone formation. Accordingly, an abundance of bone formation (Alp, Bsp), but not bone resorption (Ctsk), markers were augmented in the femurs of Cldn11 Tg mice. Since the trabecular bone density is known to inversely correlate with the amount of marrow adipose tissue (MAT), we measured the MAT in osmium-tetroxide-labeled bones by micro-CT scanning. We found 86% less MAT in the proximal tibia of the Tg males. Consistently, the expression levels of the adipogenic markers, adiponectin and leptin, were 50% lower in the femurs of the Tg males. Our data are consistent with the possibility that claudin11 exerts anabolic effects in osteoblastic lineage cells that act via promoting the differentiation of marrow stem cells towards osteoblasts at the expense of adipocytes.

Cutaneous burn injury represents a major risk factor for the development of traumatic ectopic bone formation following blast-related extremity injury

Blast-related traumatic heterotopic ossification (tHO) impacts clinical outcomes in combat-injured patients, leading to delayed wound healing, inflammatory complications, and reduced quality of life. Blast injured patients often have significant burns. This study investigated whether a partial thickness thermal burn injury exacerbates blast-related tHO in a clinically relevant polytrauma animal model. Adult male Sprague Dawley rats were subjected to an established model involving a whole-body blast overpressure exposure (BOP), complex extremity trauma followed by hind limb amputation (CET) followed by the addition of a 10 % total body surface area (TBSA) second degree thermal burn (BU). Micro-CT scans on post-operative day 56 showed a significant increase in HO volume in the CET + BU as compared to the CET alone injury group (p < .0001; 22.83 ± 3.41 mm3 vs 4.84 ± 5.77 mm3). Additionally, CET + BU concomitant with BOP significantly increased HO (p < .0001; 34.95 ± 7.71 mm3) as compared to CET + BU alone, confirming BOP has a further synergistic effect. No HO was detectable in rats in the absence of CET. Serum analysis revealed similar significant elevated (p < .0001) levels of pro-inflammatory markers (Cxcl1 and Il6) at 6 h post-injury (hpi) in the CET + BU and BOP + CET + BU injury groups as compared to naïve baseline values. Real-time qPCR demonstrated similar levels of chondrogenic and osteogenic gene expression in muscle tissue at the site of injury at 168 hpi in both the CET + BU and BOP+CET + BU injury groups. These results support the hypothesis that a 10 % TBSA thermal burn markedly enhances tHO following acute musculoskeletal extremity injury in the presence and absence of blast overpressure. Furthermore, the influence of BOP on tHO cannot be accounted for either in regards to systemic inflammation induced from remote injury or inflammatory-osteo-chondrogenic expression changes local to the musculoskeletal trauma, suggesting that another mechanism beyond BOP and BU synergistic effects are at play. Therefore, these findings warrant future investigations to explore other mechanisms by which blast and burn influence tHO, and testing prophylactic measures to mitigate the local and systemic inflammatory effects of these injuries on development of HO.

Reentry of endodontic access cavities: composite residue and loss of tooth substance.

The purpose of this study was to investigate the ability of dentists to remove composite fillings from endodontic access cavities using illumination from a conventional light source (CLS) versus the fluorescence-aided identification technique (FIT) in terms of completeness, selectivity and treatment duration. Therefore, two independent operators removed composite resin from six sets of root-filled incisors in a maxillary model under simulated clinical conditions using the CLS or FIT method (twelve teeth per operator and technique). The duration of treatment was recorded and before-after micro-CT scans were superimposed for volumetric assessment of treatment completeness and selectivity. Statistical significance was determined by t-testing and two-way ANOVA for operator comparison. Overall, there was no significant difference between FIT and CLS in terms of volume, height and area of composite residues (p=0.98 / p=0.75 / p=0.64) and regarding hard tissue loss in terms of volume, depth and area (p= 0.93 / p= 0.70 / p= 0.14). However, there was a significant difference between the two groups regarding treatment time (FIT= 428s, CLS=523s; p=0.023). Significant differences between operators regardless of method were found for volume, height and area of composite residues (p<0.05) and also for defect area (p=0.01) and time (p<0.001). Significant differences between operators including the method was only found for height of composites (p=0.037). It can be concluded, that composite remnants and tooth structure losses may occur after reentry of root-filled teeth regardless of the illumination method (conventional vs. fluorescence-aided) and operator, but preparation was less time-consuming with FIT.

Use of hare bone for the manufacture of a Clovis bead

A tubular bone bead dating to ~ 12,940 BP was recovered from a hearth-centered activity area at the La Prele Mammoth site in Converse County, Wyoming, USA. This is the oldest known bead from the Western Hemisphere. To determine the taxonomic origin of the bead, we extracted collagen for zooarchaeology by mass spectrometry (ZooMS). We also used micro-CT scanning for morphological analysis to determine likely skeletal elements used for its production. We conclude that the bead was made from a metapodial or proximal phalanx of a hare (Lepus sp.). This find represents the first secure evidence for the use of hares during the Clovis period. While the use of hare bone for the manufacture of beads was a common practice in western North America during the Holocene, its origins can now be traced back to at least the terminal Pleistocene.

Apigenin alleviates osteoporosis by orchestrating SIRT1/HIF1α signaling in mesenchymal stem cells

Osteoporosis (OP) is a systemic skeletal disease characterized by reduced bone mass and a degenerative bone microarchitecture. Apigenin (API), a flavonoid derived mainly from celery, has been reported to be beneficial for the treatment of OP; however, the underlying mechanisms remain unclear. Moreover, the effects of API on bone-forming cells, including mesenchymal stem cells and osteoblasts, remain unclear. In the present study, we first determined that API treatment could promote bone formation, improve bone metabolism in ovariectomized (OVX) mice, and effectively ameliorate bone loss, as supported by micro-CT scanning and histological staining of mouse femurs. In vitro investigations have confirmed that API has a bidirectional regulatory effect on bone metabolism, promoteing osteogenic differentiation and inhibiting osteoclastogenesis. The further study displayed that the promotion of osteogenesis of bone marrow-derived mesenchymal stem cells from OVX mice mainly through regulating SIRT1 and its downstream HIF1α signaling. In summary, API treatment may be a novel and promising therapeutic strategy for the treatment of OP.

Casticin ameliorates osteoarthritic cartilage damage in rats through PI3K/AKT/HIF-1α signaling

Knee osteoarthritis (KOA) is a chronic, disabling knee joint lesion in which degeneration and defects in articular cartilage are the most important features. Casticin (CAS) is a flavonoid extracted from the Chinese herb Vitex species that has anti-inflammatory and antitumor effects. The aim of this study was to investigate the therapeutic and mechanistic effects of CAS on cartilage damage in KOA. A KOA rat model was established by anterior cruciate ligament transection (ACLT), and cartilage morphological changes were assessed by histological analysis and micro-CT scans. Subsequently, chondrocytes were treated with 10 ng/mL IL-1β to establish an OA model. CCK-8 assays and EdU assays were performed to assess the viability of CAS-treated chondrocytes. Western blotting, flow cytometry and Hoechst 33342/PI Double Stain were used to detect chondrocyte apoptosis. Western blotting, qRT‒PCR and ELISA were used to detect changes in inflammatory mediators. In addition, cartilage matrix-related indices were detected by Western blotting, qRT‒PCR and immunofluorescence (IF) analysis. Immunohistochemistry (IHC) and Western blotting were performed to detect the expression of p-PI3K, p-AKT and HIF-1α in vivo and in vitro. Micro-CT, pathological sections and related scores showed that CAS improved the alterations in bony structures and reduced cartilage damage and osteophyte formation in the ACLT model. In vivo, CAS attenuated IL-1β-induced cartilage matrix degradation, apoptosis and the inflammatory response. In addition, CAS inhibited the expression of the PI3K/AKT/HIF-1α signaling pathway in the ACLT animal model and IL-1β cell model. CAS may ameliorate cartilage damage in OA by inhibiting the PI3K/AKT/HIF-1α signaling pathway, suggesting that CAS is a potential strategy for the treatment of OA.

Semi-Automated MicroCT Analysis of Bone Anatomy and Mineralization in Mouse Models.

The skeletal system mirrors several processes in the vertebrate body that impact developmental malfunctions, hormonal disbalance, malfunction of calcium metabolism and turn over, and inflammation processes such as arthrosis. X-ray micro computed tomography is a useful tool for 3D in situ evaluation of the skeletal system in a time-related manner, but results depend highly on resolution. Here, we provide the methodological background for a graduated evaluation from whole-body analysis of skeletal morphology and mineralization to high-resolution analysis of femoral and vertebral microstructure. We combine an expert-based evaluation with a machine-learning-based computational approach, including pre-setup analytical task lists. © 2024 Wiley Periodicals LLC. Basic Protocol 1: In vivo microCT scanning and skeletal analysis in mice Basic Protocol 2: Ex vivo high-resolution microCT scanning and microstructural analysis of the femur and L4 vertebra.