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Cdc42, a Rho family small GTPase, regulates cytoskeleton organization, vesicle trafficking, and other cellular processes in development and homeostasis. However, Cdc42's roles in prenatal tooth development remain elusive. Here, we investigated Cdc42 functions in mouse enamel organ. Cdc42 showed highly dynamic temporospatial patterns in the developing enamel organ, with robust expression in the outer enamel epithelium, stellate reticulum (SR), and stratum intermedium layers. Strikingly, epithelium-specific Cdc42 deletion resulted in cystic lesions in the enamel organ. Cystic lesions were first noted at embryonic day 15.5 and progressively enlarged during gestation. At birth, cystic lesions occupied the bulk of the entire enamel organ, with intracystic erythrocyte accumulation. Ameloblast differentiation was retarded upon epithelial Cdc42 deletion. Apoptosis occurred in the Cdc42 mutant enamel organ prior to and synchronously with cystogenesis. Transmission electron microscopy examination showed disrupted actin assemblies, aberrant desmosomes, and significantly fewer cell junctions in the SR cells of Cdc42 mutants than littermate controls. Autophagosomes were present in the SR cells of Cdc42 mutants relative to the virtual absence of autophagosome in the SR cells of littermate controls. Epithelium-specific Cdc42 deletion attenuated Wnt/β-catenin and Shh signaling in dental epithelium and induced aberrant Sox2 expression in the secondary enamel knot. These findings suggest that excessive cell death and disrupted cell-cell connections may be among multiple factors responsible for the observed cystic lesions in Cdc42 mutant enamel organs. Taken together, Cdc42 exerts multidimensional and pivotal roles in enamel organ development and is particularly required for cell survival and tooth morphogenesis. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate prostate cancer-related genes and lncRNAs by using a high throughput sequencing dataset. MATERIALS AND METHODS: RNA-seq data were obtained from the sequencing read archive database, including both benign and malignant tumor samples. After aligning the RNA-seq reads to human genome reference, gene expression profile as well as lncRNA expression profile was obtained. Next, Student's t-test was used to screen both the differentially expressed genes (DEGs) and lncRNAs (DELs) between benign and malignant samples. Finally, Goseq was used to conduct the functional annotation of DEGs. RESULTS: A total of 7112 DEGs were screened, such as ZNF512B, UCKL1, STMN3, GMEB2, and PTK6. The top 10 enriched functions of DEGs were mainly related to organism development, including multi-cellular development, system development and anatomical structure development. Also, we discovered 26 differentially expressed lncRNAs. CONCLUSIONS: The analysis used in this study is reliable in screening prostate cancer markers including both genes and lncRNAs by using RNA-seq data, which provides new insight into the understanding of molecular mechanism of prostate cancer. [ABSTRACT FROM AUTHOR]

Closed-form mixed potential Green's functions (MPGFs) for cylindrically stratified media are derived in terms of quasistatic-wave and surface-wave contributions. In order to avoid possible overflow/underflow problems in the numerical calculations of special cylindrical functions such as Bessel and Hankel functions, a novel form of the spectral-domain MPGFs is developed. Then, a two-level methodology is used for the approximation of the spectral-domain MPGFs. In the first step, the qusistatic components are extracted from the spectral-domain MPGFs, and then transformed into the space domain with the use of the Sommerfeld identity and its derivatives. In the second step, the remaining parts of the spectral-domain MPGFs are approximated in terms of pole-residue expressions via the rational function fitting method (RFFM). The proposed method is efficient and fully automatic, which avoids an analytical cumbersome extraction of the surface wave poles (SWPs), prior to the spectrum fitting. In addition, this method can evaluate the spatial-domain MPGFs accurately and efficiently for both the near- and far-fields. Finally, numerical results for the spatial-domain MPGFs of a two-layer structure are presented and discussed. [ABSTRACT FROM AUTHOR]

In this paper, an improved CBFM/p-FFT algorithm is presented, which can be applied to solve electromagnetic scattering problems of large-scale periodic composite metallic/dielectric arrays, even when the array has electrically small periodicity or separating distance. Using characteristic basis function method (CBFM), scattering characteristics of any inhomogeneous targets can be represented by special responses derived from a set of incident plane waves (PWs). In order to reserve the dominant scattering characteristics of the targets and remove the redundancy of the overfull responses, a singular value decomposition (SVD) procedure is applied, then, new series of basis functions are built based on the left singular vectors after SVD whose corresponding singular values beyond a predefined threshold. However, the algorithm of CBFM combined with method of moments (MoM) still requires a lot of memory and CPU resources to some large scale problems, so the precorrected-fast Fourier transform (p-FFT) method is applied based on the novel built basis functions, with which, the required memory and solve time for solution can be reduced in an extraordinary extent. For a near correction technique is applied to process the interactions between cells placed within a distance less than a predefined near-far field threshold, arrays with electrically small periodicity can be analyzed accurately. Moreover, the incomplete LU factorization with thresholding (ILUT) preconditioner is applied to improve the condition number of the combined algorithm, which improves the convergence speed greatly. [ABSTRACT FROM AUTHOR]

Tooth regeneration by cell delivery encounters translational hurdles. We hypothesized that anatomically correct teeth can regenerate in scaffolds without cell transplantation. Novel, anatomically shaped human molar scaffolds and rat incisor scaffolds were fabricated by 3D bioprinting from a hybrid of poly-?-caprolactone and hydroxyapatite with 200-?m-diameter interconnecting microchannels. In each of 22 rats, an incisor scaffold was implanted orthotopically following mandibular incisor extraction, whereas a human molar scaffold was implanted ectopically into the dorsum. Stromal-derived factor-1 (SDF1) and bone morphogenetic protein-7 (BMP7) were delivered in scaffold microchannels. After 9 weeks, a putative periodontal ligament and new bone regenerated atthe interface of rat incisor scaffold with native alveolar bone. SDF1 and BMP7 delivery not only recruited significantly more endogenous cells, but also elaborated greater angiogenesis than growthfactor-free control scaffolds. Regeneration of tooth-like structures and periodontal integration by cell homing provide an alternative to cell delivery, and may accelerate clinical applications. [ABSTRACT FROM AUTHOR]

Craniofacial tissue engineering promises the regeneration or de novo formation of dental, oral, and craniofacial structures lost to congenital anomalies, trauma, and diseases. Virtually all craniofacial structures are derivatives of mesenchymal cells. Mesenchymal stem cells are the offspring of mesenchymal cells following asymmetrical division, and reside in various craniofacial structures in the adult. Cells with characteristics of adult stem cells have been isolated from the dental pulp, the deciduous tooth, and the periodontium. Several craniofacial structures—such as the mandibular condyle, calvarial bone, cranial suture, and subcutaneous adipose tissue—have been engineered from mesenchymal stem cells, growth factor, and/or gene therapy approaches. As a departure from the reliance of current clinical practice on durable materials such as amalgam, composites, and metallic alloys, biological therapies utilize mesenchymal stem cells, delivered or internally recruited, to generate craniofacial structures in temporary scaffolding biomaterials. Craniofacial tissue engineering is likely to be realized in the foreseeable future, and represents an opportunity that dentistry cannot afford to miss. [ABSTRACT FROM AUTHOR]

Craniosynostosis is a congenital disorder of premature ossification of cranial sutures, occurring in one of approximately every 2500 live human births. This work addressed a hypothesis that a cranial suture can be tissue-engineered from autologous cells. Dermal fibroblasts were isolated subcutaneously from growing rabbits, culture-expanded, and seeded in a gelatin scaffold. We fabricated a composite tissue construct by sandwiching the fibroblast-seeded gelatin scaffold between two collagen sponges loaded with recombinant human BMP2. Surgically created, full-thickness parietal defects were filled with the composite tissue construct in the same rabbits from which dermal fibroblasts had been obtained. After four-week in vivo implantation, there was de novo formation of tissue-engineered cranial suture, microscopically reminiscent of the adjacent natural cranial suture. The tissue-engineered cranial suture showed radiolucency on radiographic images, in contrast to radio-opacity of microscopically ossified calvarial defects filled with fibroblast-free, BMP2-loaded constructs. This approach may be refined for tissue engineering of cranial sutures for craniosynostosis patients. [ABSTRACT FROM AUTHOR]

The mechanical properties of craniofacial sutures have rarely been investigated. Three facial sutures-the pre-maxillomaxillary (PMS), the nasofrontal (NFS), and the zygomaticotemporal (ZTS)-and their corresponding sutural mineralization fronts in 8 young New Zealand White rabbits were subjected to nano-indentation with atomic force microscopy as a test of the hypothesis that they have different mechanical properties. The average elastic modulus of the PMS was 1.46 ± 0.24 MPa (mean ± SD), significantly higher than both the ZTS (1.20 ± 0.20) and NFS (1.16 ± 0.18). The average elastic moduli of sutural mineralization fronts 30 μm away were significantly higher than their corresponding sutures and had the same distribution pattern: the PMS (2.07 ± 0.24 MPa) significantly higher than both the ZTS (1.56 ± 0.29) and NFS (1.71 ± 0.22). Analysis of these data suggests that facial sutures and their immediately adjacent sutural mineralization fronts have different capacities for mechanical deformation. The elastic properties of sutures and sutural mineralization fronts are potentially useful for improving our understanding of their roles in development. [ABSTRACT FROM AUTHOR]

The temporomandibular joint is susceptible to diseases and trauma that may ultimately lead to structural degeneration. Current approaches for replacing degenerated mandibular condyles suffer from deficiencies such as donor site morbidity, immunorejection, implant wear and tear, and pathogen transmission. The hypothesis of this study was that a human-shaped mandibular condyle can be tissue-engineered from rat mesenchymal stem cells (MSCs) encapsulated in a biocompatible polymer. Rat bone marrow MSCs were isolated and induced to differentiate into chondrogenic and osteogenic cells in vitro, and encapsulated in poly(ethylene glycol)-based hydrogel in two stratified layers molded into the shape of a cadaver human mandibular condyle. Eight weeks following in vivo implantation of the bilayered osteochondral constructs in the dorsum of immunodeficient mice, mandibular condyles formed de novo. Microscopic evaluation of the tissue-engineered mandibular condyle demonstrated two stratified layers of histogenesis of cartilaginous and osseous phenotypes. The current approach is being refined for ultimate therapeutic applications. [ABSTRACT FROM AUTHOR]

Craniofacial sutures are soft connective-tissue joints between mineralized skull bones. Suture mechanobiology refers to the understanding of how mechanical stimuli modulate sutural growth. This review's hypothesis is that novel mechanical stimuli can effectively modulate sutural growth. Exogenous forces with static, sinusoidal, and square waveforms induce corresponding waveforms of sutural strain. Sutural growth is accelerated upon small doses of oscillatory strain, as few as 600 cycles delivered 10 min/day over 12 days. Interestingly, both oscillatory tensile and compressive strains induce anabolic sutural responses beyond natural growth. Mechanistically, oscillatory strain likely turns on genes and transcription factors that activate cellular machinery via mechanotransduction pathways. Thus, sutural growth is determined by hereditary and mechanical signals via the common pathway of genes. It is concluded that small doses of oscillatory mechanical stimuli have the potential to modulate sutural growth effectively: either accelerating it or initiating net sutural bone resorption for various therapeutic objectives. [ABSTRACT FROM AUTHOR]

Whereas the growth of the cranial base cartilage is thought to be regulated solely by genes, epiphyseal growth plates are known to respond to mechanical stresses. This disparity has led to our hypothesis that chondrocyte proliferation is accelerated by mechanical stimuli above natural growth. Two-Newton tensile forces with static and cyclic waveforms were delivered in vivo to the premaxillae of actively growing rabbits for 20 min/day over 12 consecutive days. The average number of BrdU-labeled chondrocytes in the proliferating zone treated with cyclic forces was significantly higher than both static forces of matching peak magnitude and sham controls representing natural chondral growth. Cyclic forces also evoked greater area of the proliferating zone than both static forces and sham controls. Thus, chondrocyte proliferation is enhanced by mechanical stresses in vivo, especially those with oscillatory waveform. Analysis of these data suggests that genetically coded chondral growth is up-regulated by mechanical signals. [ABSTRACT FROM AUTHOR]

Craniofacial bone strain upon orthopedic loading has rarely been characterized, despite its fundamental importance in our understanding of the anabolic and catabolic effects of orthopedic forces. The present study tested the hypothesis that zygomatic bone strain is modulated upon loading by headgear, a device widely used in craniofacial orthopedics. Ramp forces from 0 to 50 Newtons were applied via headgear attached to the permanent maxillary first molars in four juvenile and five adult human skulls. The average peak bone strain of the juvenile temporal articular eminence was significantly higher than the adult articular eminence (p < 0.05). Contrasting bone strain patterns were identified in the zygomatic arch: tensile in its lateral surface but compressive in its medial surface. The peak bone strain of the temporal articular eminence and the zygomatic arch both depend upon loading direction. Thus, headgear-generated orthopedic forces evoke bending of the zygomatic arch and stresses of the temporal articular eminence in vitro, suggesting the need to verify whether bone strain induces in vivo bone modeling and remodeling. [ABSTRACT FROM AUTHOR]

The vertebrate articular tissue consists of collagen fibers embedded in a ground substance. Collagen resists tensile forces, while proteoglycans in the ground substance provide resilience and resistance to compression. It was hypothesized that unilateral bite raise would induce increasing expression of proteoglycans in TMJ articular tissues. As a test of this hypothesis, six- and nine-week-old Sprague-Dawley rats received unilateral bite-raising appliances bonded to their right upper molars for 4 wks. A group of nine-week-old rats was housed for an additional 4 wks after removal of the appliances they had worn for 4 wks. Proteoglycans that carry abundant chondroitin sulfate and keratan sulfate side-chains, most likely aggrecans, were detected by safranin O in the fibrocartilaginous zone of the condyle in parasagittal sections. A monoclonal antibody against a large chondroitin sulfate proteoglycan related to versican reacted strongly in the surface fibrous layer of the mandibular condyle and moderately in the discs of the treated specimens. Computer quantification for safranin O and anti-versican antibody staining revealed that the average intensities of the treated specimens were significantly higher than those of their corresponding sham-operated controls, and the average intensities of the treatment-reversal specimens had no significant differences from their corresponding sham-operated controls. Thus, unilateral bite raise appeared to have induced an increase in the expression of aggrecan in the condylar cartilage and a proteoglycan related to versican in the TMJ disc and the articular surface of the condyle. The elevated proteoglycan expression is interpreted to suggest that unilateral bite raise leads to an increase in the magnitude of compressive forces in the rat temporomandibular joint. [ABSTRACT FROM AUTHOR]

Objective: To determine the incidence of and risk factors for dose-limiting chemotherapy induced peripheral neuropathy (CIPN) in non-metastatic breast cancer. Methods: This retrospective cohort study included 488 women with an adjuvant or neoadjuvant treatment plan with docetaxel or paclitaxel from June 1, 2009 to December 31, 2011. Exclusion criteria were: metastatic disease, previous neurotoxic chemotherapy, preexisting neuropathy, pregnant or within 3 months post-partum, and prosthetic limb. The primary outcome was dose-limiting CIPN, defined as a treatment modification event (dose delay, dose reduction, or treatment discontinuation) attributed to CIPN. The primary risk factor of interest was obesity (BMI 30). Covariates included race, age, menopausal status, diabetes, and other comorbidities, node status, tumor size, regimen, and oncologist. With 80% power and 0.05 type I error rate, the study could detect a risk ratio of 1.8 in the obese versus non-obese. Results: Fifty (10.2%) women had a treatment modification event attributed to CIPN (TMCIPN). TM-CIPN incidence differed significantly by agent (docetaxel = 2.4% (N = 5/209), paclitaxel=16.1% (N = 45/279); p < 0.001). In analyses restricted to patients treated with paclitaxel with complete covariate data (N = 273), the odds of TM-CIPN did not differ by obesity, OR = 1.17 (95% CI 0.59-2.35). After adjusting for black race, menopausal status, disease severity, and type II diabetes the TM-CIPN and obesity association was attenuated. The attenuation occurred after adjustment for black race, which was a confounder of the obesity and TM-CIPN relationship, and associated with obesity (OR = 3.78, p = <0.001). Post-menopausal status, disease severity, and type II diabetes were associated with obesity, but were not confounders. Compared to whites, and after controlling for disease severity, menopausal status, and oncologist, blacks and other nonwhites had significantly increased odds of CIPN-TM (OR = 2.5, p < 0.02; OR = 4.8, p < 0.01; respectively). Tests of homogeneity indicated the race and TM-CIPN association was not modified by oncologist or disease severity. Conclusion: Obese and non-obese women have a comparable likelihood of having their treatment modified due to CIPN. Women of racial minorities had over 2-to 4-fold increased odds of TM-CIPN compared to white women. Investigations addressing the mechanistic explanations for this association are warranted. [ABSTRACT FROM AUTHOR]

Insulin-like peptides (ILPs) act through a conserved insulin signaling pathway and play crucial roles in insect metabolism, growth, reproduction, and aging. Application of bovine insulin is able to increase vitellogenin (Vg) mRNA and protein levels in female insects. Here, we first show that injection of bovine insulin into previtellogenic Chrysopa septempunctata female adults promoted ovarian growth, increased Vg protein abundance, elevated reproductive performance, and enhanced protease activity. These data suggested that ILPs play crucial roles in reproductive regulation of the green lacewing, C. septempunctata.

Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose.

Dentin in permanent teeth rarely undergoes resorption in development, homeostasis, or aging, in contrast to bone that undergoes periodic resorption/remodeling. The authors hypothesized that cells in the mesenchymal compartment of dental pulp attenuate osteoclastogenesis. Mononucleated and adherent cells from donor-matched rat dental pulp (dental pulp cells [DPCs]) and alveolar bone (alveolar bone cells [ABCs]) were isolated and separately cocultured with primary rat splenocytes. Primary splenocytes readily aggregated and formed osteoclast-like cells in chemically defined osteoclastogenesis medium with 20 ng/mL of macrophage colony-stimulating factor (M-CSF) and 50 ng/mL of receptor activator of nuclear factor κB ligand (RANKL). Strikingly, DPCs attenuated osteoclastogenesis when cocultured with primary splenocytes, whereas ABCs slightly but significantly promoted osteoclastogenesis. DPCs yielded ~20-fold lower RANKL expression but >2-fold higher osteoprotegerin (OPG) expression than donor-matched ABCs, yielding a RANKL/OPG ratio of 41:1 (ABCs:DPCs). Vitamin D3 significantly promoted RANKL expression in ABCs and OPG in DPCs. In vivo, rat maxillary incisors were atraumatically extracted (without any tooth fractures), followed by retrograde pulpectomy to remove DPCs and immediate replantation into the extraction sockets to allow repopulation of the surgically treated root canal with periodontal and alveolar bone-derived cells. After 8 wk, multiple dentin/root resorption lacunae were present in root dentin with robust RANKL and OPG expression. There were areas of dentin resoprtion alternating with areas of osteodentin formation in root dentin surface in the observed 8 wk. These findings suggest that DPCs of the mesenchymal compartment have an innate ability to attenuate osteoclastogenesis and that this innate ability may be responsible for the absence of dentin resorption in homeostasis. Mesenchymal attenuation of dentin resorption may have implications in internal resorption in the root canal, pulp/dentin regeneration, and root resorption in orthodontic tooth movement., (© International & American Associations for Dental Research 2015.)

Objective: There are limited clinical treatments for temporomandibular joint (TMJ) pathologies, including degenerative disease, disc perforation and heterotopic ossification (HO). One barrier hindering the development of new therapies is that animal models recapitulating TMJ diseases are poorly established. The objective of this study was to develop an animal model for TMJ cartilage degeneration and disc pathology, including disc perforation and soft tissue HO., Methods: New Zealand white rabbits (n = 9 rabbits) underwent unilateral TMJ disc perforation surgery and sham surgery on the contralateral side. A 2.5 mm defect was created using a punch biopsy in rabbit TMJ disc. The TMJ condyles and discs were evaluated macroscopically and histologically after 4, 8 and 12 weeks. Condyles were blindly scored by four independent observers using OARSI recommendations for macroscopic and histopathological scoring of osteoarthritis (OA) in rabbit tissues., Results: Histological evidence of TMJ condylar cartilage degeneration was apparent in experimental condyles following disc perforation relative to sham controls after 4 and 8 weeks, including surface fissures and loss of Safranin O staining. At 12 weeks, OARSI scores indicated experimental condylar cartilage erosion into the subchondral bone. Most strikingly, HO occurred within the TMJ disc upon perforation injury in six rabbits after 8 and 12 weeks., Conclusion: We report for the first time a rabbit TMJ injury model that demonstrates condylar cartilage degeneration and disc ossification, which is indispensible for testing the efficacy of potential TMJ therapies., (Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The temporomandibular joint (TMJ) undergoes degenerative changes among patients who suffer from arthritis, and yet the pathogenesis of TMJ osteoarthritis and rheumatoid arthritis is poorly understood. We hypothesized that sustained inflammation in the TMJ induces structural abnormalities, and accordingly characterized the disc and synovium in a novel model with double injections of complete Freund's adjuvant (CFA), using behavioral, morphological, cellular, and molecular assessments. Thirty-five days following double CFA injections in seven-week-old female Sprague-Dawley rats, the disc in the CFA-induced inflammation group demonstrated multiple degenerative changes, including marked thickening, opacity, and deformation. The discs in the CFA group further showed significantly greater wet and net weights, and elevated collagen, aggrecan, and total glycosaminoglycan contents. The synovium in the CFA-induced inflammation group showed marked infiltration of mononucleated cells and accumulated sub-synovial adipose tissue. Both the disc and synovium had significantly higher iNOS and IL-1β mRNA expression than controls (saline injections). These findings are consistent with our hypothesis that sustained TMJ inflammation, even within the presently observed 35 days, may be a predisposing factor for structural abnormalities. Insight into TMJ inflammation and degeneration is anticipated to improve our understanding of the pathogenesis of TMJ arthritis and help design clinically relevant strategies for tissue engineering.

Dental pulp has intrinsic capacity for self-repair. However, it is not clear whether dental pulp cells can be recruited endogenously for regenerating pulp tissues, including mineralizing into dentin. This work is based on a hypothesis that dental pulp stem/progenitor cells can be induced to migrate by chemotactic cytokines and act as endogenous cell sources for regeneration and mineralization. Dental stem cells (DSCs) were isolated from adult human tooth pulp and seeded on the surfaces of 3D collagen gel cylinders that were incubated in chemically defined media with stromal-derived factor-1α (SDF1), basic fibroblast growth factor (bFGF), or bone morphogenetic protein-7 (BMP7). Significantly more cells were recruited into collagen gel by SDF1 or bFGF than without cytokines in 7 days, whereas BMP7 had little effect on cell recruitment. BMP7, however, was highly effective, equally to dexamethasone, in orchestrating mineralization of cultured DSCs. Cell membrane receptors for SDF1, bFGF, and BMP7 were up-regulated in treated DSCs. Upon in vivo delivery, bFGF induced re-cellularization and re-vascularization in endodontically treated human teeth implanted into the dorsum of rats. Thus, endogenous dental pulp cells, including stem/progenitor cells, may be recruited and subsequently differentiated by chemotaxis of selective cytokines in the regeneration of dental pulp.