Exploring the anatomy of Linguatula serrata using micro-computed tomography.

Micro-computed tomography (micro-CT) is an emerging tool in parasitology that can assist in analysing morphology and host-parasitic interactions. It is a non-destructive, cross-sectional imaging technique that offers good resolution and the ability to create three-dimensional (3D) reconstructions. Here, we used micro-CT to study Linguatula serrata, which is a zoonotic pentastome parasite that infects dogs and ruminants throughout the world. The aims of this study were to describe the internal and external anatomy of adult L. serrata specimens using micro-CT, and to describe and compare specimens stained with 0.3% phosphotungstic acid (PTA) and 1% iodine (I2). Ten adult L. serrata specimens were subjected to micro-CT examination. The specimens were fixed in 70% ethanol and stained with 0.3% PTA or 1% I2. Both stains offered good tissue contrast. The main identifying external features of L. serrata (hooks, mouth, buccal cadre) were clearly visible. Virtual sections and 3D reconstructions provided a good overview of the coelomic cavity, with visualisation of the digestive tract, nervous system, and male and female reproductive organs. These micro-CT images and morphological descriptions may serve as an anatomical reference for L. serrata, in particular, the internal anatomy which has not been described in recent years.

Comparison of Micro-CT and Morphometric Outcomes in a Modified Experimental Rat Model of Periodontitis.

AIM: To assess the correlation between micro-computed tomography (micro-CT) and linear morphometric measurements in terms of mandibular bone levels in a modified experimental periodontitis model in rodents to study the mechanisms of association between periodontal destruction and neuroinflammation. METHODS: The proposed in vivo experimental periodontitis model involves the administration of oral rinses with Porphyromonas gingivalis and Fusobacterium nucleatum, four times per week during 4, 8 or 12 weeks, in 24 male Wistar Hannover rats (180 g, 5 weeks old). After euthanasia, hemi-mandibles were collected. One hemi-mandible was analysed using morphometry, while the other was assessed with micro-CT. Linear measurements were taken at the buccal aspect and furcation level for both techniques, and volumetric measurements were also obtained with micro-CT. Passing-Bablok regression analysis was used to compare the results of both techniques, with morphometric measurements serving as the reference. Moreover, Lin's Concordance correlation coefficient was calculated to assess the level of agreement. Periodontal clinical variables with neuroinflammatory parameters from the frontal cortex were used to evaluate the association between the resulting condition and neuroinflammation. RESULTS: Twenty-one out of the initial 24 rats were analysed. The micro-CT linear measurements demonstrated high concordance values with the linear morphometric measurements at the buccal surfaces of the roots in molars (r = 0.714) but not at the furcation area (r = 0.052). At 12 weeks, there was a significant impact on neuroinflammation with significant decreases in iNOS levels and p-mTOR levels at 4 and 8 weeks. CONCLUSION: The proposed in vivo experimental periodontitis model demonstrated a high degree of correlation between morphometric and micro-CT measurements in buccal areas but not at the furcation level. Concomitantly, there was a significant temporary modulation of the neuroinflammatory response.

Longitudinal Micro-Computed Tomography Detects Onset and Progression of Pulmonary Fibrosis in Conditional Nedd4-2 Deficient Mice.

OBJECTIVES: Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease which is usually diagnosed late in advanced stages. Little is known about the subclinical development of IPF. We previously generated a mouse model with conditional Nedd4-2 deficiency (Nedd4-2-/-) that develops IPF-like lung disease. The aim of this study was to characterize the onset and progression of IPF-like lung disease in conditional Nedd4-2-/- mice by longitudinal micro-computed tomography (CT). METHODS: In vivo micro-CT was performed longitudinally in control and conditional Nedd4-2-/- mice at 1, 2, 3, 4 and 5 months after doxycycline induction. Further, terminal in vivo micro-CT followed by pulmonary function testing and post mortem micro-CT was performed in age-matched mice. Micro-CT images were evaluated for pulmonary fibrosis using an adapted fibrosis scoring system. Histological assessment of lung collagen content was conducted as well. RESULTS: Micro-CT is sensitive to detect onset and progression of pulmonary fibrosis in vivo and to quantify distinct radiological IPF-like features along disease development in conditional Nedd4-2-/- mice. Nonspecific interstitial alterations were detected from 3 months, whereas key features such as honeycombing-like lesions were detected from 4 months onwards. Pulmonary function correlated well with in vivo (r=-0.738) and post mortem (r=-0.633) micro-CT fibrosis scores and collagen content. CONCLUSION: Longitudinal micro-CT enables in vivo monitoring of onset and progression and detects radiologic key features of IPF-like lung disease in conditional Nedd4-2-/- mice. Our data support micro-CT as sensitive quantitative endpoint for preclinical evaluation of novel antifibrotic strategies.

Root canal cleanliness and debris extrusion following retreatment of thermoplastic injection technique and bioceramic-based root canal sealer.

OBJECTIVES: To evaluate the amount of apically extruded debris and to determine the remaining filling material on the root canal walls by microcomputed tomography (micro-CT), following the root canal retreatment of root canals filled with different obturation techniques (single cone technique, thermoplasticised injection technique) and the different root canal sealers [bioceramic-based, epoxy resin-based root canal sealer]. MATERIALS AND METHODS: 60 single rooted human premolar teeth were prepared with the ProTaper Gold system (Dentsply Maillefer) up to the F4 file and the samples were divided into 4 groups according to obturation procedures: Single cone technique + AH Plus sealer(epoxy resin-based root canal sealer, Dentsply International Inc., York, PA, USA); Single cone technique + Sure-Seal Root(bioceramic-based root canal sealer, Sure Dent Corporation, Gyeonggi-do, South Korea); thermoplastic injection technique[Calamus Dual Obturation System(Dentsply-Tulsa Dental, Tulsa, OK, USA)] + AH Plus(Dentsply International Inc.); Sure-Seal Root(Sure Dent Corporation) + Calamus Dual Obturation System (Dentsply-Tulsa Dental). The teeth were inserted into preweighed Eppendorf tubes and retreatment was performed. The tubes were kept in an incubator at 37 °C for 14 days to obtain the dry debris weight. Following the removal of the root canal fillings, the samples were scanned with a micro-CT device to analyse the volume of filling residues. RESULTS: Retreatment of samples obturated with epoxy-resin or bioceramic based root sealers combined with Calamus system resulted in higher amount of apical extrusion compared to their combination with single cone technique (p = 0.026 for Single cone technique + AH Plus sealer vs Calamus + AH Plus sealer and p = 0.005 for Single cone technique + Sure-Seal root sealer vs Calamus + Sure-Seal root sealer). The most debris was observed in the Calamus + Sure-Seal root sealer group, the least debris was observed in the Single cone technique + AH Plus sealer group. The percentage of residues was the highest in the Single cone technique + Sure-Seal root sealer and the lowest in the Calamus + AH Plus sealer group, but there were no significant differences between groups (p = 0.463). CONCLUSIONS: No correlation was observed among the groups in terms of extruded debris and remnants inside the root canal. When combined with bioceramic based sealer, thermoplasticised injection technique did not affect the cleanliness of root canal walls; however, it increased its apical extrusion potential during retreatment. CLINICAL RELEVANCE: The obturation method does not play a role in the removability of bioceramic based root canal sealer, however the use of bioceramic-based root canal sealers with cold obturation techniques may be beneficial in preventing apical extrusion.

Lead Toxicity and Maternal Exposure: Characterisation of Alveolar Bone Changes on Offspring Rats.

Lead poisoning is a global public health concern. Maternal exposure during intrauterine and lactational periods can present a higher susceptibility of harm to the offspring. Thus, pregnant female Wistar rats (Rattus norvegicus) were randomly divided in two experimental groups: control group and Lead group. The animals were exposed to 50 mg/kg of Lead Acetate daily for 42 days (21 days of gestational period + 21 days of lactational period). After the exposure period, the mandibles of the offspring were collected for lead quantification, Raman spectroscopy analysis, micro-CT, morphometric e histochemical analysis. Lead exposure altered the physical-chemical composition of alveolar bone and caused histological damage associated with a reduction in osteocyte density and collagen area fraction, increase in collagen maturity, as well as a reduction in bone volume fraction. An increase in trabecular spaces with anatomical compromise of the vertical dimensions of the bone was observed. Thus, the results suggest that developing alveolar bone is susceptible to toxic effects of lead when organisms are exposed during intrauterine and lactation periods.

Three-Dimensional Internal Voids and Marginal Adaptation in Deep Margin Elevation Technique: Efficiency of Highly Filled Flowable Composites.

PURPOSE: To evaluate interfacial three-dimensional adaptation and internal voids of different flowable materials before and after cyclic fatigue in a simulated deep-margin elevation scenario. METHODS: Eighty (n = 80) extracted premolars were selected and two Class II cavities were prepared. The mesial one with cervical margin 1 mm above the cementum-enamel junction (CEJ) and the distal one with cervical margin 1 mm below the CEJ. After performing adhesive procedures, specimens were divided into four groups according to the employed materials for 2 mm horizontal deep-margin relocation: nanohybrid composite (Clearfil ES2, Kuraray); conventional viscosity flowable composite (Tetric Flow, Ivoclar); medium viscosity flowable composite (Majesty ES2 Low Flow, Kuraray); high viscosity flowable composite (Majesty ES2 Super Low Flow, Kuraray). All restorations were finalized by oblique layering with nanohybrid composite (Clearfil ES2, Kuraray). To reveal interfacial and internal gap progression, specimens were scanned with a micro-CT (SkyScan 1172), before and after 500,000 cycles of mechanical chewing simulation (50 N, 1 Hz). Data were imported into Mimics software after smoothing and region growing. Only the 2 mm margin relocation volumes were considered. Obtained masks were analyzed for noise removal and volume calculation. At baseline, interfacial gap progression and internal voids, expressed in mm3, were collected and statistically analyzed with two-way ANOVA (α 0.05) for the variables substrate and restorative materials followed by Tukey post-hoc test. An additional two-way ANOVA test, followed by Tukey post-hoc test, was performed to evaluate variation in interfacial gap progression after mechanical aging. RESULTS: At baseline, the ANOVA test showed a significant difference for the variable restorative materials (p = 0.01). More specifically, the Tukey post-hoc test revealed that the highly filled medium viscosity composite performed better than the conventional viscosity composite at baseline for the interfacial gap. The internal voids ANOVA test at baseline reported no significant differences for the variable tested. Analysis of variance for internal gap progression after thermocycling showed no differences for both substrate and restorative material employed. CONCLUSIONS: Highly filled medium viscosity composite performed significantly better than the conventional viscosity flowable composite for what concern baseline interfacial gaps. Artificial aging with a chewing simulator and thermocycling did not affect interfacial gap progression on enamel and dentin. The tested restorative materials performed equally after aging.

Physicochemical and Morphological Changes in Long-Grain Brown Rice Milling: A Study Using Image Visualization Technologies.

This study evaluated the changes in physicochemical properties and appearance quality of long-grain rice during the grinding process using image technologies and aimed to provide reference for future research. The brown rice milling process was divided into three stages, and flatbed scanning, scanning electron microscopy (SEM), X-ray micro-computed tomography (micro-CT), low-field nuclear magic resonance (LF-NMR), and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) were employed to examine the physicochemical and volatile properties of the samples. Results revealed a continuous increase in the degree of milling, with a broken rice rate and a whiteness value increasing by 50.84% and 21.13%, respectively, compared with those during the initial stage; dietary fiber and vitamin B1 contents were reduced by 54.41% and 66.67%, respectively. The image results visualized showed that the cortex of brown rice was gradually peeled off with the increase in milling degree; the cortical thickness was gradually reduced, the endosperm was gradually exposed, and the surface was smoother and shinier. T2 populations exhibited a shift toward longer relaxation times, followed by a decrease in relaxation time during the milling process. Additionally, 31 target compounds impacting rice flavor, mainly ketones, alcohols, and esters, were identified, and the concentration of volatile substances in the B region decreased with the reduction in the bran layer; the concentration of volatile substances in the C region provided rice flavor, which increased with the milling process. This study showed changes in the physicochemical properties and appearance quality of long-grain brown rice during milling. Furthermore, the use of various image processing techniques offers significant insights for optimizing processing parameters and enhancing overall quality and taste.

Microarchitectural properties of compacted cancellous bone allografts: A morphology micro-computed tomography analysis.

Massive bone loss poses a significant challenge in defect reconstruction. The use of compacted allografts is a valuable technique to reconstruct bone stock. This study aimed to assess the impact of compression on the microstructure of native cancellous bone chips with a micro-CT analysis. Bone samples were harvested from 15 femoral heads donated by patients who underwent total hip arthroplasty. Bone chips were prepared using a bone mill. All samples with the same weight were compressed by 25% and 50% of their original volume and subsequently scanned with a micro-CT scanner to determine the microarchitectural morphology of the bone chips. Uniaxial compression test was carried out before and after a standardized compaction procedure. Comparing the samples without compaction to 50%, the number of trabeculae doubled, the volume ratio doubled, and the trabeculae spacing was reduced, showing voids of 800 µm on average. The number of interlocking possibilities tripled, while no differences were seen in the trabeculae morphology. Uniaxial compression test showed a yield limit after compaction of 0.125 MPa. Interlocking might occur three times more with a denser material than in a non-compacted sample. The increase in density comparable to manual intraoperative compaction did not lead to significant fragmentation of the allograft material. The assessed microarchitecture should, therefore, reassemble the intraoperative situation during a manual bone impaction procedure.

Influence of Endodontic Cavity Design on Interfacial Voids, Class II Resin Composites Sealing Ability and Tooth Fracture Resistance: An In Vitro Study.

Objective: The aim of this in vitro investigation is to study the effect of endodontic cavity design on interfacial voids, class II resin composite sealing ability, and fracture resistance in mandibular premolars. Methods: A total of 48 single-rooted mandibular premolars received compound class II preparations with either traditional flare access cavities (group A) or contracted endodontic cavity preparations (group B). Each study group was subdivided according to the coronal restoration into two sub-groups as α and ß. In the α group, a microhybrid composite was used after etch-and-rinse bonding technique using an MDP-containing universal adhesive. In the ß group, a self-adhesive composite was used as coronal restoration after endodontic treatment (n = 12) for each subgroup. A micro-CT analysis was performed to assess the obturation interfacial voids and tracing of class II cervical interfacial adaptation. The tooth fracture resistance testing was then performed adding an extra group of 12 sound non-prepared teeth, which were tested as the control for fracture strength testing. A one-way ANOVA and post-hoc testing were used together with descriptive statistics for an analysis of the mean values of obturation interfacial voids. A two-way ANOVA was used to assess the fracture resistance test results, and to find the influence of endodontic access design and the type of composite material on the fracture resistance testing. Chi-square testing was employed to analyze the cervical interfacial seal of the class II restorations. Results: A one-way ANOVA revealed that there were no statistically significant differences between test groups in the amount of obturation interfacial voids (p > 0.05). There were no statistically significant differences between test groups in terms of cervical interfacial sealing ability (p > 0.05). A two-way ANOVA revealed that no statistically significant differences between test groups including the control group existed in terms of the fracture resistance testing (p > 0.05). Conclusions: Although it does not improve tooth fracture resistance, the contracted endodontic access cavity does not deteriorate the quality of obturation in terms of the interfacial porosity. The self-adhesive composite does not improve the efficiency of cervical interfacial adaptation or tooth fracture resistance regardless of the endodontic access cavity shape, yet it revealed a substantial load-bearing capacity.

Contrast-Enhanced Micro-CT Imaging of Murine Mandibles: A Multi-Method Approach for Simultaneous Hard and Soft Tissue Analysis.

AIM: To develop and evaluate a novel multi-method micro-computed tomography (µCT) imaging protocol for enhanced visualization of both hard and soft tissues in murine mandibles, addressing the limitations of traditional imaging techniques in dental research. MATERIALS AND METHODS: We employed a contrast-enhanced (CE) µCT imaging technique using Lugol's iodine as a contrast agent to visualize the intricate structures of murine mandibles. The protocol involved the combination of conventional µCT imaging as well as CE-µCT, including decalcification with EDTA, allowing for simultaneous assessment of hard and soft tissues. The method is compared with standard imaging modalities, and the ability to visualize detailed anatomical features is discussed. RESULTS: The CE-µCT imaging technique provided superior visualization of murine mandibular structures, including dental pulp, periodontal ligaments and the surrounding soft tissues, along with conventional µCT imaging of alveolar bone and teeth. This method revealed detailed anatomical features with high specificity and contrast, surpassing traditional imaging approaches. CONCLUSION: Our findings demonstrate the potential of CE-µCT imaging with Lugol's iodine as a powerful tool for dental research. This technique offers a comprehensive view of the murine mandible, facilitating advanced studies in tissue engineering, dental pathology and the development of dental materials.

Variation in air sac morphology and postcranial skeletal pneumatization patterns in the African grey parrot.

The anatomy of the avian lower respiratory system includes a complex interaction between air-filled pulmonary tissues, pulmonary air sacs, and much of the postcranial skeleton. Hypotheses related to the function and phylogenetic provenance of these respiratory structures have been posed based on extensive interspecific descriptions for an array of taxa. By contrast, intraspecific descriptions of anatomical variation for these features are much more limited, particularly for skeletal pneumatization, and are essential to establish a baseline for evaluating interspecific variation. To address this issue, we collected micro-computed tomography (µCT) scans of live and deceased African grey parrots (Psittacus erithacus) to assess variation in the arrangement of the lungs, the air sacs, and their respective invasion of the postcranial skeleton via pneumatic foramina. Analysis reveals that the two pairs of caudalmost air sacs vary in size and arrangement, often exhibiting an asymmetric morphology. Further, locations of the pneumatic foramina are more variable for midline, non-costal skeletal elements when compared to other pneumatized bones. These findings indicate a need to better understand contributing factors to variation in avian postcranial respiratory anatomy that can inform future intraspecific and interspecific comparisons.

Laser-assisted Root Canal Filling Removal of Lower Incisors - A Micro-CT Study.

Aim: To compare the efficiency of root canal filling removal from oval-shaped root canals with high-energy Er:YAG laser and additional instrumentation with a rotary Ni-Ti XP-Endo Finisher R system. Materials and Methods: The in vitro study was accomplished on 12 freshly extracted single-rooted mandibular incisors with one straight oval-shaped root canal, shaped with XP-Endo Shaper 30/.04 and obturated by using the warm vertical condensation technique subjected to further endodontic orthograde retreatment. Group 1: the first retreatment was carried out using a high-energy Er:YAG laser (n = 12). Group 2: the additional retreatment of the same specimens was performed with the XP-Endo Finisher-R system (n = 12). The effectiveness of the retreatment techniques was evaluated by a threefold micro-CT examination. The amount of the remaining root canal filling material was analyzed by Mann-Whitney U test and Friedman tests. Results: A significant decrease in the quantity of the root canal filling was found following the first and after the second retreatment, compared to the initial values in all examined sections (P < 0.001). Within groups, additional application of the Ni-Ti system resulted in no significant removal of the filling materials (P > 0.05). Conclusions: None of the systems resulted in complete root canal filling removal. Despite the improved results after the application of the supplementary retreatment protocol, none of the root canal walls were completely clean in the apical area. The high-energy Er:YAG laser and XP-Endo Finisher R rotary system can be successfully used in endodontic orthograde retreatment under relevant operating parameters.

A perspective view of salt crystallization from solution in porous media: morphology, mechanism, and salt efflorescence.

Salt efflorescence is one of the major hazards to cultural heritages, masonries, and highways etc. It is now generally accepted that damages caused by salt efflorescence are mainly due to continuous cycles of salt crystallization/dissolution or hydration/dehydration in confined spaces. The position where salt efflorescence occurs and its type are closely related to the degree of damages caused by salt efflorescence. It is known that water is the key environmental factor determining the salt crystallization position. But influence of the correlation between water supply and evaporation on the position of salt crystallization is still not clearly understood. In this work, a set of experiments are designed to investigate salt efflorescence in porous matrix. It is found that the types and positions of salt efflorescence have little to do with nucleation, but are mainly governed by crystal growth, which is controlled by the rates of water evaporation, water and salt supply, capillary forces and surface properties of the porous matrices.

Mechanical and Corrosion Behaviour in Simulated Body Fluid of As-Fabricated 3D Porous L-PBF 316L Stainless Steel Structures for Biomedical Implants.

Laser powder bed fusion (L-PBF) is one of the most promising additive manufacturing technologies for creating customised 316L Stainless Steel (SS) implants with biomimetic characteristics, controlled porosity, and optimal structural and functional properties. However, the behaviour of as-fabricated 3D 316L SS structures without any surface finishing in environments that simulate body fluids remains largely unknown. To address this knowledge gap, the present study investigates the surface characteristics, the internal porosity, the corrosion in simulated body fluid (SBF), and the mechanical properties of as-fabricated 316L SS structures manufactured by L-PBF with rhombitruncated cuboctahedron (RTCO) unit cells with two distinct relative densities (10 and 35%). The microstructural analysis confirmed that the RTCO structure has a pure austenitic phase with a roughness of ~20 µm and a fine cellular morphology. The micro-CT revealed the presence of keyholes and a lack of fusion pores in both RTCO structures. Despite the difference in the internal porosity, the mechanical properties of both structures remain within the range of bone tissue and in line with the Gibson and Ashby model. Additionally, the as-fabricated RTCO structures demonstrated passive corrosion behaviour in the SBF solution. Thus, as-fabricated porous structures are promising biomaterials for implants due to their suitable surface roughness, mechanical properties, and corrosion resistance, facilitating bone tissue growth.

A comparison between in vitro and randomized in situ models for remineralization of artificial enamel lesions.

The randomized study aimed to evaluate the comparability of in situ (iS) and in vitro (iV) study protocols regarding remineralization of artificial enamel lesions. Two toothpastes (group A: 1450 ppm sodium fluoride, group B: placebo 0 ppm F-), were investigated. IV, a pH-cycling model with toothpaste slurry treatment was applied for 10d. IS, remineralization was performed in 9 participants wearing splints with embedded enamel samples for 10 and 21d, randomly allocated to groups A and B. Samples were scanned by X-ray micro-computed tomography (µCT) and grayscale value line profiles corresponding to mineral density (rel.ΔZ) were analyzed. Statistical analyses were performed using MedCalc Statistical Software, v22.021. T-Test for dependent and independent data and analysis of variance (ANOVA) were used for further analyses (α = 0.05). Rel.ΔZ of fluoride treated samples (A) were iV = 40.2%, iS 10d = 11.5% and iS 21d = 46.1% (p > 0.05). Rel.ΔZ of placebo treated samples (B) were: iV = - 6.2%, iS 10d = 25.2% and iS 21d = 11.0% (p > 0.05). Remineralization potential of both toothpastes was significantly different regarding iV (p < 0.001) and iS after 21d (p = 0.034), while in case of iS 10d no significant difference was detected (p = 0.4). Despite different study protocols the µCT results after remineralization were comparable between iV and iS. The results suggest that selected studies can be carried out in faster, simplified iV studies using pH-cycling instead of iS studies.

On the influence of structural and chemical properties on the elastic modulus of woven bone under healing.

Introduction: Woven bone, a heterogeneous and temporary tissue in bone regeneration, is remodeled by osteoblastic and osteoclastic activity and shaped by mechanical stress to restore healthy tissue properties. Characterizing this tissue at different length scales is crucial for developing micromechanical models that optimize mechanical parameters, thereby controlling regeneration and preventing non-unions. Methods: This study examines the temporal evolution of the mechanical properties of bone distraction callus using nanoindentation, ash analysis, micro-CT for trabecular microarchitecture, and Raman spectroscopy for mineral quality. It also establishes single- and two-parameter power laws based on experimental data to predict tissue-level and bulk mechanical properties. Results: At the macro-scale, the tissue exhibited a considerable increase in bone fraction, controlled by the widening of trabeculae. The Raman mineral-to-matrix ratios increased to cortical levels during regeneration, but the local elastic modulus remained lower. During healing, the tissue underwent changes in ash fraction and in the percentages of Calcium and Phosphorus. Six statistically significant power laws were identified based on the ash fraction, bone fraction, and chemical and Raman parameters. Discussion: The microarchitecture of woven bone plays a more significant role than its chemical composition in determining the apparent elastic modulus of the tissue. Raman parameters were demonstrated to provide more significant power laws correlations with the micro-scale elastic modulus than mineral content from ash analysis.

Osteoarthritis early-, mid- and late-stage progression in the rat medial meniscus transection model.

Osteoarthritis is a degenerative disease of synovial joints affecting all tissues, including articular cartilage and subchondral bone. Osteoarthritis animal models can recapitulate aspects of human disease progression and are used to test efficacy of drugs, biomaterials, and cell therapies. The rat medial meniscus transection (MMT) model is a surgically induced posttraumatic osteoarthritis model commonly used for preclinical therapeutic screening. We describe herein, the qualitative and quantitative changes to articular cartilage, subchondral bone, and formation of osteophytes at early-, mid-, and late-stages of osteoarthritis progression. Tibia of MMT-operated animals showed proteoglycan loss and fibrillation along articular cartilage surfaces as early as 3-weeks post-surgery. With contrast-enhanced micro-CT technique, quantitative, 3-dimensional analysis of the tibia showed that the articular cartilage thickened at 3- and 6-weeks post-surgery and decreased at 12-weeks post-surgery. This decreased cartilage thickness corresponded with increased lesions in the articular cartilage that led to its full degradation and exposing the subchondral bone layer. Further, subchondral bone thickening was significant at 6-weeks post-surgery and followed cartilage damage. Osteophytes were found as early as 3-weeks post-surgery and coincided with articular cartilage degradation. Cartilaginous osteophytes preceded mineralization, suggesting endochondral ossification. The rat MMT model has predominantly been used out to 3-weeks, and most studies determined the effect of therapies to delay or prevent the onset of osteoarthritis. We provide evidence that an extension of the rat MMT model out to 6- and 12-weeks more resembled severe phenotypes of human osteoarthritis. Thus, evaluating novel therapeutics at late-stage will be important for eventual clinical translation.

Phylogeny and systematics of the colubrid snake genera Liopeltis and Gongylosoma (Squamata: Colubridae) and description of a new Himalayan endemic genus and species.

The colubrid snakes of the genera Gongylosoma Fitzinger, 1843 and Liopeltis Fitzinger, 1843 are distributed across south and southeast Asia with five and eight nominate species, respectively. Despite their wide distribution, members of these genera are among some of the least-known colubrids. The two genera were considered synonymous in the past only to be separated later, and are defined on rather nebulose characters with a lack of support from molecular data. To test the monophyly of the two genera, we generated molecular data for the type species of Gongylosoma and species representing the two genera, including samples of Liopeltis rappii (Günther, 1860) from the western Himalayas. Results recovered paraphyly of Liopeltis, especially with regard to the genus Gongylosoma. Morphological data supports recognizing the western and eastern populations of L. rappii as two distinct species. The findings from our integrative taxonomic approach advocate establishing a new genus to embody Liopeltis rappii and a new allied species from the central and western Himalayas. A rediagnosis and revised classification of the genera Gongylosoma and Liopeltis is presented. The results further hint at cryptic diversity across members of the two genera, warranting scrutiny of the most widespread members of the group.

Computationally derived endosteal strain and strain gradients correlate with increased bone formation in an axially loaded murine tibia model.

Osteoporosis is a common metabolic bone disorder characterized by low bone mass and microstructural degradation of bone tissue due to a derailed bone remodeling process. A deeper understanding of the mechanobiological phenomena that modulate the bone remodeling response to mechanical loading in a healthy bone is crucial to develop treatments. Rodent models have provided invaluable insight into the mechanobiological mechanisms regulating bone adaptation in response to dynamic mechanic stimuli. This study sheds light on these aspects by means of assessing the mechanical environment of the cortical and cancellous tissue to in vivo dynamic compressive loading within the mouse tibia using microCT-based finite element model in combination with diaphyseal strain gauge measures. Additionally, this work describes the relation between the mid-diaphyseal strains and strain gradients from the finite element analysis and bone formation measures from time-lapse in vivo tibial loading with a fluorochrome-derived histomorphometry analysis. The mouse tibial loading model demonstrated that cancellous strains were lower than those in the midshaft cortical bone. Sensitivity analyses demonstrated that the material property of cortical bone was the most significant model parameter. The computationally-modeled strains and strain gradients correlated significantly to the histologically-measured bone formation thickness at the mid-diaphyseal cross-section of the mouse tibia.

African cichlid fishes: morphological data and taxonomic insights from a genus-level survey of supraneurals, pterygiophores, and vertebral counts (Ovalentaria, Blenniiformes, Cichlidae, Pseudocrenilabrinae).

Background: The iconic freshwater cichlid fishes (Cichlidae) comprise about 1750 validly named species and hundreds more that are known, but not yet described and named. Cichlids are an important source of protein for millions of people on several continents, are model organisms in studies of evolution, speciation, ecology, development, behaviour and physiology and are popular as aquarium fishes. Yet, comparative studies of cichlid internal anatomy are rare. Even their osteology has not been taxonomically surveyed. The cichlid postcranial skeleton has been especially neglected. New information: Here, I provide the first survey in cichlids of the considerable variation in numbers of vertebrae, supraneurals and dorsal- and anal-fin supports (pterygiophores), as well as the patterns with which the pterygiophores insert between the neural or haemal spines. The study includes some 1700 specimens of nearly 400 cichlid species. Focusing on the largest subfamily, the African cichlids or Pseudocrenilabrinae, the survey furnishes data from species in all but one of its 166 genera. Limited data from species in the other cichlid subfamilies (Etroplinae, Ptychochrominae and Cichlinae) and from the related leaffishes, Polycentridae, are also presented. Key examples of pterygiophore insertion patterns from throughout the range of variation are illustrated and discussed. Detailed analytical tables and all raw data are provided in supplementary files.A bizarre specialisation in Cyprichromis is noted, evidently for the first time. Uniquely in this Lake Tanganyikan genus, five to seven anal pterygiophores are abdominal in position, located anterior to the anal fin and inserting toward or between successive pairs of pleural ribs.Taxonomic changes: The most speciose tribe of African cichlids, currently known as Haplochromini, is correctly called Pseudocrenilabrini. Based chiefly on the molecular phylogenetic findings of other workers, I propose four pseudocrenilabrine subtribes, one occurring in rivers and three endemic to Lake Malawi. I also re-assign the Lake Tanganyikan tribe Tropheini as another subtribe of Pseudocrenilabrini, in line with numerous molecular studies placing tropheines firmly within this tribe. The remaining genera of Pseudocrenilabrini remain incertae sedis in this tribe pending clarification of their phylogenetic relationships.The character complex here surveyed is a promising source of taxonomically and phylogenetically informative characteristics distinguishing or uniting cichlid taxa at multiple hierarchical levels, from species through subfamily. This reference set of novel character data can also provide information for palaeontological studies of African cichlids. These attributes are skeletal features potentially available for study in well preserved fossils and may help determine their correct taxonomic placement.