The mechanisms related to fibroblasts in burn surface.

PURPOSE: Mesenchymal stem cells (MSCs) can promote burn wound healing, skin appearance, and function recovery by promoting the differentiation and migration of fibroblasts of a wound. The burn environment can activate the autophagy of MSCs. However, it is not clear whether this autophagy can affect the proliferation and migration of fibroblasts. METHODS: In this study, pretreated MSCs with rapamycin and 3-methyladenine modulated autophagy and co-cultured with fibroblasts of burn. Cell migration was detected by immunofluorescence chemical staining. Western blot analysis and enzyme-linked immunosorbent assay were performed to detect 2,3-Dioxygenase (IDO), cytokine synthesis inhibitory factor 10 (IL-10), cytokine synthesis inhibitory factor 6 (IL-6), prostaglandin E2 (PGE2), transforming growth factor beta 1 (TGF-ß1) proteins levels, and the autophagy proteins p62 and microtubule-associated protein LC3-II/I. RESULTS: We demonstrated that autophagy regulates MSCs survival and proliferation in burn wound transplants and found that autophagy inhibition with 3-methyladenine reduced MSCs-mediated, fibroblast proliferation and migration in burn environment. However, rapamycin-induced autophagy had the opposite effect and increased the TGF-ß1 expression. Therefore, we speculate that MSCs may promote fibroblast proliferation and migration by secreting TGF-ß1 via the AKT/mTOR (RAC-alpha serine/threonine-protein kinase/mammalian target of rapamycin) pathway. CONCLUSION: Autophagy of MSCs regulates burn wound fibroblast proliferation and migration by affecting TGF-ß1 and prostaglandin E2 production adjacent to MSCs transplanted on the burn wound. The results of this study provide a potential strategy for promoting MSCs treatment of burns.

The effect of the root dilaceration on the treatment duration and prognosis of unilateral impacted immature maxillary central incisors.

INTRODUCTION: This study aimed to investigate the effect of root dilaceration on the closed-eruption technique treatment and prognosis on impacted immature maxillary central incisors. METHODS: In this retrospective study, we compared the age at the beginning of the treatment, the treatment duration, root development, and alveolar bone mass after the closed-eruption technique between the impacted immature maxillary central incisors with dilacerated roots (group 1) and those with straight roots (group 2). RESULTS: The mean age at the time of the surgery of group 1 was 0.9 years younger than that of group 2 (P = 0.008). The mean traction time was greater in group 1 (8.0 ± 1.8 months), with a difference of 1.4 months than in group 2 (6.6 ± 2.1 months) (P = 0.042). The measurements of lingual bone thickness at the alveolar crest (C) showed significant differences between the 2 groups (P = 0.025). No significant differences were found in other treatment duration or measurements of root development and alveolar bone mass between the 2 groups. CONCLUSIONS: Patients with impacted immature incisors with dilacerated roots were younger at the beginning of the closed-eruption treatment and had a longer traction time than those with impacted immature incisors having straight roots. The root dilaceration had little or no effect on root development and alveolar bone mass after the closed-eruption treatment. The closed-eruption treatment of impacted immature incisors with root dilaceration is suggested to commence as early as possible.

Orrella daihaiensis sp. nov., a bacterium isolated from Daihai Lake in Inner Mongolia.

A novel aerobic, Gram-staining-negative, non-motile, short-rod-shaped strain, designated f23T, was obtained from Daihai Lake, Inner Mongolia, Republic of China. 16S rRNA gene sequences analysis showed that f23T belongs to the genus Orrella and is most closely related to Orrella marina H-Z20T with 98.35% sequence similarity. The strain was oxidase positive, catalase positive and had well growth at pH 6.5-8.5, at temperature 28-40 °C and at 0-4.5% (w/v) NaCl. Colonies incubated at 37 °C on marine 2216 agar for 3 days were white, smooth, transparent, circular and less than 1.0 mm in diameter. The total genome size of f23T was 2,803,849 bp with a G + C content of 52.79%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain f23T and O. marina H-Z20T were 69.62% and 20.5%, which both below the species delineation threshold. Chemotaxonomic analysis showed that C16:0, cyclo-C17:0, C18:0, Sum Feature 3 (C16:1ω7c and/or C16:1ω6c) and Sum Feature 8 (C18:1ω6c and C18:1ω7c) as the major fatty acids, ubiquinone-8 as the major isoprenoid quinone, phosphatidylethanolamine as the major cellular polar lipids. Based on the polyphasic analysis, f23T represents a novel species within the genus Orrella, for which the name Orrella daihaiensis sp. nov. is proposed. The type strain is f23T (= CGMCC 1.18761 T = KCTC 82425 T).

CircRNA circ_0006892 regulates miR-24/PHLPP2 axis to mitigate cigarette smoke extract-induced bronchial epithelial cell injury.

Chronic obstructive pulmonary disease (COPD) is a chronic airway disorder mainly resulted from cigarette smoke exposure. The dysregulated circular RNAs (circRNAs) are relevant to the pathogenesis of COPD. This study aims to explore the function and mechanism of circRNA hsa_circ_0006892 (circ_0006892) in cigarette smoke extract (CSE)-induced bronchial epithelial injury. The lung tissues were collected from 17 nonsmokers and 23 smokers with COPD. The bronchial epithelial cells (BEAS-2B and 16HBE) were stimulated via CSE. Circ_0006892, microRNA-24 (miR-24), and PH domain and leucine-rich repeat protein phosphatase 2 (PHLPP2) abundances were examined via a quantitative reverse transcription polymerase chain reaction or Western blot. Cell viability, apoptosis, and inflammatory response were assessed via cell counting kit-8 (CCK-8), flow cytometry, and enzyme-linked immunosorbent assay (ELISA). The target relationship of miR-24 and circ_0006892 or PHLPP2 was tested via dual-luciferase reporter analysis, RNA immunoprecipitation, and RNA pull-down. Circ_0006892 expression was reduced in lung tissues of smokers with COPD and CSE-stimulated bronchial epithelial cells. Circ_0006892 overexpression alleviated CSE-induced viability reduction and promotion of apoptosis and inflammatory response. MiR-24 was bound via circ_0006892, and miR-24 overexpression reversed the effect of circ_0006892 on CSE-induced injury. PHLPP2 was targeted via miR-24, and miR-24 knockdown mitigated CSE-induced viability reduction and promotion of apoptosis and inflammatory response via regulating PHLPP2. Circ_0006892 could promote PHLPP2 expression via regulating miR-24. Circ_0006892 attenuated CSE-induced bronchial epithelial cell apoptosis and inflammatory response via regulating miR-24/PHLPP2 axis.

A novel ENAM mutation causes hypoplastic amelogenesis imperfecta.

OBJECTIVES: To identify the genetic cause of one Chinese family with hypoplastic amelogenesis imperfecta (AI) and explore the relationship between genotype and its phenotype. MATERIAL AND METHODS: One Chinese family with generalized hypoplastic AI was recruited. One deciduous tooth from the proband was subjected to scanning electron microscopy. Whole-exome sequencing was performed and identified mutation was confirmed by Sanger sequencing. Bioinformatics studies were further conducted to analyze potential deleterious effects of the mutation. RESULTS: The proband presented a typical hypoplastic AI phenotype whose teeth in deciduous and permanent dentitions showed thin, yellow, and hard enamel surface. The affected enamel in deciduous tooth showed irregular, broken, and collapsing enamel rods with borders of the enamel prisms undulated and structural shapes of prisms irregular. A novel homozygous nonsense mutation in the last exon of the enamelin (ENAM) gene (NM_031889.3; c.2078C>G) was identified in the proband, which was predicted to produce a highly truncated protein (NP_114095.2; p.(Ser693*)). This mutation was also identified in the proband's parents in heterozygous form. Surprisingly, the clinical phenotype of the heterozygous parents varied from a lack of penetrance to mild enamel defects. Additional bioinformatics studies demonstrated that the detected mutation could change the 3D structure of the ENAM protein and severely damaged the function of ENAM. CONCLUSION: The novel homozygous ENAM mutation resulted in hypoplastic AI in the present study. Our results provide new genetic evidence that mutations involved in ENAM contribute to hypoplastic AI.

Energy Loss and Radial Force Variation Caused by Impeller Trimming in a Double-Suction Centrifugal Pump.

Impeller trimming is an economical method for broadening the range of application of a given pump, but it can destroy operational stability and efficiency. In this study, entropy production theory was utilized to analyze the variation of energy loss caused by impeller trimming based on computational fluid dynamics. Experiments and numerical simulations were conducted to investigate the energy loss and fluid-induced radial forces. The pump's performance seriously deteriorated after impeller trimming, especially under overload conditions. Energy loss in the volute decreased after trimming under part-load conditions but increased under overload conditions, and this phenomenon made the pump head unable to be accurately predicted by empirical equations. With the help of entropy production theory, high-energy dissipation regions were mainly located in the volute discharge diffuser under overload conditions because of the flow separation and the mixing of the main flow and the stalled fluid. The increased incidence angle at the volute's tongue after impeller trimming resulted in more serious flow separation and higher energy loss. Furthermore, the radial forces and their fluctuation amplitudes decreased under all the investigated conditions. The horizontal components of the radial forces in all cases were much higher than the vertical components.

New Function of RUNX2 in Regulating Osteoclast Differentiation via the AKT/NFATc1/CTSK Axis.

Cleidocranial dysplasia is an autosomal dominant skeletal disorder resulting from RUNX2 mutations. The influence of RUNX2 mutations on osteoclastogenesis and bone resorption have not been reported. To investigate the role of RUNX2 in osteoclast, RUNX2 expression in macrophages (RAW 264.7 cells) was detected. Stable RAW 264.7 cell lines expressing wild-type RUNX2 or mutated RUNX2 (c.514delT, p.172 fs) were established, and their functions in osteoclasts were investigated. Wild-type RUNX2 promoted osteoclast differentiation, formation of F-actin ring, and bone resorption, while mutant RUNX2 attenuated the positive differentiation effect. Wild-type RUNX2 increased the expression and activity of mTORC2. Subsequently, mTORC2 specifically promoted phosphorylation of AKT at the serine 473 residue. Activated AKT improved the nuclear translocation of NFATc1 and increased the expression of downstream genes, including CTSK. Inhibition of AKT phosphorylation abrogated the osteoclast formation of wild-type macrophages, whereas constitutively activated AKT rescued the osteoclast formation of mutant macrophages. The present study suggested that RUNX2 promotes osteoclastogenesis and bone resorption through the AKT/NFATc1/CTSK axis. Mutant RUNX2 lost the function of regulating osteoclast differentiation and bone remodeling, resulting in the defective formation of the tooth eruption pathway and impaction of permanent teeth in cleidocranial dysplasia. This study, for the first time, verifies the effect of RUNX2 on osteoclast differentiation and bone resorption and provides new insight for the explanation of cleidocranial dysplasia.

Differentiating atypical hemangiomas and vertebral metastases: a field-of-view (FOV) and FOCUS intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) study.

PURPOSE: Some atypical vertebral hemangiomas (VHs) may mimic metastases on routine MRI and can result in misdiagnosis and ultimately to additional imaging, biopsy and unnecessary costs. The purpose of this study is to assess the utility of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) on account of field-of-view optimized and constrained undistorted single shot (FOCUS) in distinguishing atypical VHs and vertebral metastases. METHODS: A total of 25 patients with vertebral metastases and 25 patients with atypical VHs were confirmed by clinical follow-up or pathology. IVIM-DWI imaging was performed at different b values (0, 30, 50, 100, 150, 200, 400, 600, 800, 1000 mm2/s). IVIM parameters [the true diffusion coefficient (D), pseudodiffusion coefficient (D*), standard apparent diffusion coefficient (ADC), and perfusion fraction (f)] were calculated and compared between two groups by using Student's t test. A receiver operating characteristic analysis was performed. RESULTS: Quantitative analysis of standard ADC and D parameters showed significantly lower values in vertebral metastases when compared to atypical hemangiomas [ADC value: (0.70 ± 0.12) × 10-3 mm2/s vs (1.14 ± 0.28) × 10-3 mm2/s; D value: (0.47 ± 0.07) × 10-3 mm2/s vs (0.76 ± 0.14) × 10-3 mm2/s, all P < 0.01]. The sensitivity and specificity of D value were 93.8% and 92.3%, respectively. CONCLUSION: The standard ADC value and D value may be used as an indicator to distinguish vertebral metastases from atypical VHs. FOCUS IVIM-derived parameters provide potential value in the quantitatively differentiating vertebral metastases from vertebral atypical hemangiomas.

Cd uptake by Phytolacca americana L. promoted by cornstalk biochar amendments in Cd-contaminated soil.

Cadmium (Cd) contamination is the most extensive pollution in China farmland. A greenhouse pot trial was conducted to investigate the effects of cornstalk biochar on Cd accumulation by Phytolacca americana L. (pokeweed) in Cd-contaminated soil. The Cd concentration increased in leaves, shoots, and roots of plants amended with 5% biochar by 79%, 113%, and 32%, respectively, compared with the pokeweed without biochar. The Cd availability, soil Cd speciation, soil fertility, root biomass, and Cd chemical forms in root were investigated to explore the mechanism by which Cd uptake increased in presence of biochar. The extractability of Cd by DTPA decreased in presence of biochar by 30% compared with that of soil without biochar. The increases occurred with dose of biochar increased in available phosphorus, labile organic carbon, and C/N atom ratio. Although, the dry weight of the aboveground part of the pokeweed decreased by 38.5%, however, the weight of roots increased by 20.8%. Root biomass and microbial activity reached maximum in the treatment that recieved 5% biochar. Cd forms extracted by NaCl and acetic acid (HAc) were predominant in root. When 5% biochar applied to soil, HAc-extracted Cd took up maximum of the increase in root.

Magnetic field assisted laser fabrication and electrical characterizations of metal dry Biolectrode with surface microstructures.

Magnetic field assisted laser fabrication is proposed to process metal dry bioelectrode with surface microstructures. The effects of magnetic flux density on the geometrical dimension of surface microstructures of bioelectrode is investigated. The electrode-skin contact impedance is then studied using the two-electrode measurement method. Finally, electromyography (EMG) signal is recorded using bioelectrodes processed in different magnetic flux density. Our results show that the magnetic field has obvious influences on the height and bottom width of microstructure of bioelectrode. When a magnetic field of 100 mT is selected, larger height-width ratio of microstructures is obtained, which provides a stronger ability to penetrate stratum corneum. Consequently, much lower contact impedance is obtained. Signal-noise ratio (SNR) of EMG signal shows a correlation coefficient of 0.9836 with height-width ratio of microstructures on the surface of metal dry bioelectrodes. Raw EMG signals recorded by metal dry bioelectrodes in 100 mT magnetic field show a high SNR up to 27.350, which is slightly higher than that of traditional Ag/AgCl wet bioelectrodes (26.689). By stationary wavelet transform (SWT) de-noising, noise interfused in raw EMG signals is suppressed effectively. Moreover, the de-noised EMG signal recorded using metal dry bioelectrodes processed in 100 mT magnetic field still remains a fairly high SNR.

FOXO1 regulates VEGFA expression and promotes angiogenesis in healing wounds.

Angiogenesis is a critical aspect of wound healing. We investigated the role of keratinocytes in promoting angiogenesis in mice with lineage-specific deletion of the transcription factor FOXO1. The results indicate that keratinocyte-specific deletion of Foxo1 reduces VEGFA expression in mucosal and skin wounds and leads to reduced endothelial cell proliferation, reduced angiogenesis, and impaired re-epithelialization and granulation tissue formation. In vitro FOXO1 was needed for VEGFA transcription and expression. In a porcine dermal wound-healing model that closely resembles healing in humans, local application of a FOXO1 inhibitor reduced angiogenesis. This is the first report that FOXO1 directly regulates VEGFA expression and that FOXO1 is needed for normal angiogenesis during wound healing. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

RUNX2 mutation reduces osteogenic differentiation of dental follicle cells in cleidocranial dysplasia.

Disturbed permanent tooth eruption is common in cleidocranial dysplasia (CCD), a skeletal disorder caused by heterozygous mutation of RUNX2, but the mechanism underlying is still unclear. As it is well known that dental follicle cells (DFCs) play a critical role in tooth eruption, the changed biological characteristics of DFCs might give rise to disturbance of permanent tooth eruption in CCD patients. Thus, primary DFCs from one CCD patient and normal controls were collected to investigate the effect of RUNX2 mutation on the bone remodeling activity of DFCs and explore the mechanism of impaired permanent tooth eruption in this disease. Conservation and secondary structure analysis revealed that the RUNX2 mutation (c.514delT, p.172fs) found in the present CCD patient was located in the highly conserved RUNT domain and converted the structure of RUNX2. After osteogenic induction, we found that the mineralised capacity of DFCs and the expression of osteoblast-related genes, including RUNX2, ALP, OSX, OCN and Col Iα1, in DFCs was severely interfered by the RUNX2 mutation found in CCD patients. To investigate whether the osteogenic deficiency of DFCs from the CCD patient can be rescued by RUNX2 restoration, we performed 'rescue' experiments. Surprisingly, the osteogenic deficiency and the abnormal expression of osteoblast-associated genes in DFCs from the CCD patient were almost rescued by overexpression of wild-type RUNX2 using lentivirus. All these findings indicate that RUNX2 mutation can reduce the osteogenic capacity of DFCs through inhibiting osteoblast-associated genes, thereby disturbing alveolar bone formation, which serves as a motive force for tooth eruption. This effect may provide valuable explanations and implications for the mechanism of delayed permanent tooth eruption in CCD patients.

A novel FAM83H mutation in one Chinese family with autosomal-dominant hypocalcification amelogenesis imperfecta.

Autosomal-dominant hypocalcification amelogenesis imperfecta (ADHCAI) is characterized by soft enamel that easily disintegrates and exposed dark dentin. ADHCAI is caused by mutations in a gene called family with sequence similarity 83 member H (FAM83H). To investigate the molecular genetics of ADHCAI, a Chinese family in which three generations exhibited ADHCAI was recruited. The enamel ultrastructure was analysed by environmental scanning electron microscopy (ESEM), which showed altered enamel rod (prism) structures in ADHCAI patients compared to the structures in healthy controls. Mutational analysis of the FAM83H gene identified a novel nonsense mutation (c.1222A>T) in the affected family members that encodes a stop codon at amino acid position 408, causing premature protein truncation (p. K408X). Green fluorescent protein (GFP) and FAM83H fusion protein analyses in vitro showed that normal cytoplasmic accumulation of the FAM83H protein was prevented by the K408X mutation in both rat dental epithelial SF2 cells and human embryonic kidney 293T cells. The mutant fusion protein localized primarily to the nucleus, in contrast to the cytoplasmic subcellular localization of the wild-type FAM83H protein. Our results provide new genetic evidence that mutations in FAM83H contribute to ADHCAI.

Abnormal bone remodelling activity of dental follicle cells from a cleidocranial dysplasia patient.

OBJECTIVES: To explore the role of dental follicle cells (DFCs) with a novel cleidocranial dysplasia (CCD) causative gene RUNX2 mutation (DFCsRUNX2+/m ) in delayed permanent tooth eruption. MATERIALS AND METHODS: A CCD patient with typical clinical features was involved in this study. DFCsRUNX2+/m were cultured and DNA was extracted for RUNX2 mutation screening. Measurements of cell proliferation, alkaline phosphatase (ALP) activity, alizarin red staining and osteoblast-specific genes expression were performed to assess osteogenesis of DFCsRUNX2+/m . Co-culture of DFCs and peripheral blood mononuclear cells (PBMCs), followed tartrate-resistant acid phosphatase (TRAP) staining, real-time PCR and western blot were performed to evaluate osteoclast-inductive capacity of DFCsRUNX2+/m . RESULTS: A missense RUNX2 mutation (c. 557G>C) was found in DFCsRUNX2+/m from the CCD patient. Compared with normal controls, this mutation did not affect the proliferation of DFCsRUNX2+/m , but down-regulated the expression of osteogenesis-related genes, leading to a decrease in ALP activity and mineralisation. Co-culture results showed that DFCsRUNX2+/m reduced the formation of TRAP+ multinucleated cells and the expression of osteoclastogenesis-associated genes. Furthermore, the mutation reduced the ratio of RANKL/OPG in DFCsRUNX2+/m . CONCLUSIONS: DFCsRUNX2+/m disturbs bone remodelling activity during tooth eruption through RANK/RANKL/OPG signalling pathway and may thus be responsible for impaired permanent tooth eruption in CCD patients.

High-Q Wafer Level Package Based on Modified Tri-Layer Anodic Bonding and High Performance Getter and Its Evaluation for Micro Resonant Pressure Sensor.

In order to achieve and maintain a high quality factor (high-Q) for the micro resonant pressure sensor, this paper presents a new wafer level package by adopting cross-layer anodic bonding technique of the glass/silicon/silica (GSS) stackable structure and integrated Ti getter. A double-layer structure similar to a silicon-on-insulator (SOI) wafer is formed after the resonant layer and the pressure-sensitive layer are bonded by silicon direct bonding (SDB). In order to form good bonding quality between the pressure-sensitive layer and the glass cap layer, the cross-layer anodic bonding technique is proposed for vacuum package by sputtering Aluminum (Al) on the combination wafer of the pressure-sensitive layer and the resonant layer to achieve electrical interconnection. The model and the bonding effect of this technique are discussed. In addition, in order to enhance the performance of titanium (Ti) getter, the prepared and activation parameters of Ti getter under different sputtering conditions are optimized and discussed. Based on the optimized results, the Ti getter (thickness of 300 nm to 500 nm) is also deposited on the inside of the glass groove by magnetron sputtering to maintain stable quality factor (Q). The Q test of the built testing system shows that the number of resonators with a Q value of more than 10,000 accounts for more than 73% of the total. With an interval of 1.5 years, the Q value of the samples remains almost constant. It proves the proposed cross-layer anodic bonding and getter technique can realize high-Q resonant structure for long-term stable operation.

RUNX2 mutation impairs bone remodelling of dental follicle cells and periodontal ligament cells in patients with cleidocranial dysplasia.

RUNX2 is an important osteo-specific factor with crucial functions in bone formation and remodelling as well as resorption of teeth. Heterozygous mutation of RUNX2 can cause cleidocranial dysplasia (CCD), a systemic disease with extensive skeletal dysplasia and abnormality of tooth growth. In our study, dental follicle cells (DFCs) and periodontal ligament cells (PDLCs) were isolated, cultured and identified from one patient with CCD and compared with normal controls. This CCD patient was confirmed to have a heterozygous frameshift mutation of RUNX2 (c.514delT, p.Ser172fs) in the previous study. The results showed that the proliferation abilities of DFCs and PDLCs were both disturbed by the RUNX2 mutation in the CCD patient compared with the normal control. A co-culture system of these cells with human peripheral blood mononuclear cells was then used to investigate the effect of RUNX2 mutation on osteoclastogenesis. We found that the RUNX2 mutation in CCD reduced the expression of osteoclast-related genes, such as RUNX2, CTR, CTSK, RANKL and OPG The ability of osteoclastogenesis in DFCs and PDLCs detected by tartrate-resistant acid phosphatase staining in the co-culture system was also reduced by the RUNX2 mutation compared with the normal control. These outcomes indicate that the RUNX2 mutation disturbs the modulatory effects of DFCs and PDLCs on the differentiation of osteoclasts and osteoblasts, thereby interfering with bone remodelling. These effects may contribute in part to the pathological manifestations of retention of primary teeth and delayed eruption of permanent teeth in patients with CCD.

Evaluation of root and alveolar bone development of unilateral osseous impacted immature maxillary central incisors after the closed-eruption technique.

INTRODUCTION: In this study, we evaluated root and alveolar bone development in unilateral osseous impacted immature maxillary central incisors by cone-beam computed tomography before and after closed-eruption treatment, in comparison with naturally erupted contralateral immature maxillary central incisors. METHODS AND RESULTS: The study included 30 patients, 20 boys and 10 girls, with a mean age of 8.44 ± 1.20 years (range, 6.5-11.2 years). After treatment, the root lengths of both the impacted maxillary central incisors (10.66 ± 2.10 mm) and the contralateral maxillary central incisors (11.04 ± 1.76 mm) were significantly greater than their pretreatment values (6.67 ± 1.94 and 9.02 ± 2.13 mm, respectively). The root canal widths of the incisors decreased significantly after treatment. From the posttreatment cone-beam computed tomography images, the ratio of exposed root length to total root length and the thickness of the alveolar bone at 1 mm under the alveolar crest and at the apex were calculated to evaluate alveolar bone development. Impacted immature maxillary central incisors differed significantly from contralateral immature maxillary central incisors in labial exposed root length, labial ratio to total root length, and lingual alveolar crest. Clinical crown height was higher (statistically but not clinically) for the impacted incisors (9.87 mm) than for the contralateral incisors (9.37 mm). CONCLUSIONS: Impacted immature incisors grew to the same stage as did erupted contralateral incisors after closed-eruption treatment. Both incisor types had some alveolar bone loss, and thin alveolar bone surrounded the roots.

A novel mutation in GPR68 causes hypomaturation amelogenesis imperfecta.

OBJECTIVES: To identify the genetic cause of a Chinese family with hypomaturation amelogenesis imperfecta (AI) and to characterize the structure of GPR68 mutated enamel in order to develop a deeper understanding of the role of the GPR68 protein during the intricate process of amelogenesis. DESIGN: One Chinese family with generalized hypomaturation AI was recruited. Two of the third molars from the proband were subjected to scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Whole exome sequencing (WES) was performed, and the identified mutation was confirmed by Sanger sequencing. Bioinformatics studies were further conducted to analyze the potential deleterious effects of the mutation. RESULTS: The proband presented with a hypomaturation AI phenotype, characterized by fragile and discolored enamel surface. The AI enamel showed prismatic structure, which was sporadically obscured by areas of amorphous material and porous structure. EDX analysis showed the proband's enamel demonstrated a significant decrease in calcium and phosphorus content and a significant increase in oxygen compared with normal enamel. A novel homozygous mutation of G protein-coupled receptor 68 (GPR68) (c .149 T > A, p.Ile50Asn) was identified in the proband. Bioinformatics analysis indicated that the mutation site displayed a high level of evolutionary conservation among species, and the mutation might impact the stability and conformation of the protein. CONCLUSION: The novel homozygous GPR68 mutation resulted in hypomaturation AI. We first described the effect of GPR68 mutation on enamel structure. Our results provide new genetic evidence that mutations involved in GPR68 contribute to hypomaturation AI.

A novel nonsense mutation in PAX9 is associated with sporadic hypodontia.

The most important events during the regulation of tooth development were inductive interactions between the epithelial and mesenchymal tissues. The expression of Pax9 had been shown to specifically mark the mesenchymal regions at the prospective sites of all teeth prior to any morphological manifestations. Here, we investigated the PAX9 gene as a candidate gene for hypodontia in five unrelated Chinese patients with tooth agenesis. Direct sequencing and restriction enzyme analysis revealed a novel heterozygous mutation c.480C>G (p.160Tyr>X, Y160X) in a patient who was missing 20 permanent teeth (the third molars excluded) and 6 primary teeth. The mutation was a nonsense mutation, leading to a premature stop codon in exon 2 of PAX9 gene. PCR analysis of complementary DNA from cultured lymphocytes of the affected individual could not indicate the complete degradation of the mutated transcript. Promoter reporter assays revealed reduced transcriptional activity of the mutated PAX9 protein suggesting that the severe phenotype may result from haploinsufficiency of PAX9. In another patient with 15 missing permanent teeth (the third molars excluded), we found the c.219insG mutation previously reported by Stockton.

Solitary Median Maxillary Central Incisor Syndrome: An Exploration of the Pathogenic Mechanism.

This study aimed to identify the genetic cause of one Chinese family with solitary median maxillary central incisor (SMMCI) and explore the relationship between genotype and its phenotype. One Chinese family with clinical diagnosis of SMMCI was collected. Single Nucleotide Polymorphism (SNP) array was performed and identified variation was confirmed by whole-genome sequencing (WGS). The reported chromosomal abnormalities and pathogenic genes in patients with SMMCI in literature were reviewed and summarized. The proband was an 8-year-old boy presenting a typical solitary median maxillary central incisor with a range of other phenotypic anomalies, including ptosis. SNP array revealed a 14.3 Mbp heterozygous deletion at chromosome 18p11.32-p11.21 in the proband but not in the unaffected parents. WGS further confirmed the identified deletion. 194 genes were involved in the chromosome region. Among them, 12 genes had been shown to be associated with diseases, including TGIF1, a reported SMMCI gene. The de novo 18p deletion resulted in SMMCI in the present study. Our results provide new genetic evidence that structural abnormality in chromosome 18p contributes to solitary median maxillary central incisor.