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A bimetallic, two-coordinated carbene-metal-amine (cMa) Au(I) complex featuring a twisted tandem carbene structure (NHC1-Au-NHC2-Au-carbazolyl) was synthesized. The molecular structure in single crystals revealed a large dihedral angle between the two carbene ligands, while the bridged carbene NHC2 and carbazolyl (Cz) ligands were coplanar. A bluish green thermally stimulated delayed phosphorescence (TSDP) was observed in crystals with an emission lifetime over 70 µs, which can be attributed to the spin allowed diabatic population of a high-lying emissive triplet state from the 3LE characterized low-lying ones. The small rotation energy barrier of Cz along the coordination bond allowed conformers with large dihedral angles between NHC2 and Cz. The ICT characterized S1 state was consequently stabilized to achieve a thermally accessible energy gap to facilitate ISC between triplets and the S1, leading to the thermally activated delayed fluorescence (TADF). Simultaneous TSDP and TADF dual emission can be recorded in its doped polymer film owing to the coexistence of these different conformers.
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Since the emergence of the first green light emission from a fluorescent thin-film organic light emitting diode (OLED) in the mid-1980s, a global consumer market for OLED displays has flourished over the past few decades. This growth can primarily be attributed to the development of noble metal phosphorescent emitters that facilitated remarkable gains in electrical conversion efficiency, a broadened color gamut, and vibrant image quality for OLED displays. Despite these achievements, the limited abundance of noble metals in the Earth's crust has spurred ongoing efforts to discover cost-effective electroluminescent materials. One particularly promising avenue is the exploration of thermally activated delayed fluorescence (TADF), a mechanism with the potential to fully harness excitons in OLEDs. Recently, investigations have unveiled TADF in a series of two-coordinate coinage metal (Cu, Ag, and Au) complexes. These organometallic TADF materials exhibit distinctive behavior in comparison to their organic counterparts. They offer benefits such as tunable emissive colors, short TADF emission lifetimes, high luminescent quantum yields, and reasonable stability. Impressively, both vacuum-deposited and solution-processed OLEDs incorporating these materials have achieved outstanding performance. This review encompasses various facets on two-coordinate TADF coinage metal complexes, including molecular design, photophysical characterizations, elucidation of structure-property relationships, and OLED applications.
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Coordinated manganese (Mn) electrocatalysts owing to their electronic structure flexibility, non-toxic and earth abundant features are promising for electrocatalytic reactions. However, achieving selective hydrogen peroxide (H2 O2 ) production through two electron oxygen reduction (2e-ORR) is a challenge on Mn-centered catalysts. Targeting this goal, we report on the creation of a secondary Mn(II)-coordinated active environment with reactant enrichment effect on boundary-rich porous carbon-based electrocatalysts, which facilitates the selective and rapid synthesis of H2 O2 through 2e-ORR. The catalysts exhibit nearly 100 % Faradaic efficiency and H2 O2 productivity up to 15.1â mol gcat -1 h-1 at 0.1â V versus reversible hydrogen electrode, representing the record high activity for Mn-based electrocatalyst in H2 O2 electrosynthesis. Mechanistic studies reveal that the epoxide and hydroxyl groups surrounding Mn(II) centers improve spin state by modifying electronic properties and charge transfer, thus tailoring the adsorption strength of *OOH intermediate. Multiscale simulations reveal that the high-curvature boundaries facilitate oxygen (O2 ) adsorption and result in local O2 enrichment due to the enhanced interaction between carbon surface and O2 . These merits together ensure the efficient formation of H2 O2 with high local concentration, which can directly boost the tandem reaction of hydrolysis of benzonitrile to benzamide with nearly 100 % conversion rate and exclusive benzamide selectivity.
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A phytochemical investigation of the steroidal saponins from the rhizomes of Paris polyohylla var. latifolia led to the discovery and characterization of three new spirostanol saponins, papolatiosides A-C (1-3), and nine known compounds (4-12). Their structures were established via extensive spectroscopic data analysis and chemical methods. Interestingly, compounds 1 and 2 possessed a fructosyl in their oligosaccharide moiety, which is rare in natural product and was firstly reported in family Melanthiaceae. The cytotoxicity of these saponins against several human cancer cell lines was evaluated by a CCK-8 experiment. As a result, compound 1 exhibited a significant cytotoxic effect on LN229, U251, Capan-2, HeLa, and HepG2 cancer cells with IC50 values of 4.18 ± 0.31, 3.85 ± 0.44, 3.26 ± 0.34, 3.30 ± 0.38 and 4.32 ± 0.51 µM, respectively. In addition, the result of flow cytometry analysis indicated that compound 1 could induce apoptosis of glioma cells LN229. The underlying mechanism was explored by network pharmacology and western bolt experiments, which indicated that compound 1 could induce glioma cells LN229 apoptosis by regulating the EGFR/PI3K/Akt/mTOR pathway.
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Antineoplásicos , Glioma , Liliaceae , Melanthiaceae , Saponinas , Humanos , Rizoma/química , Fosfatidilinositol 3-Quinasas , Liliaceae/química , Antineoplásicos/análisis , Saponinas/farmacología , Saponinas/químicaRESUMEN
Four new polyhydroxylated steroidal saponins, parisverticillatosides A-D (1-4), together with four known spirostanol saponins (5-8) were isolated from the roots of Paris verticillata. Their structures were elucidated on the basis of extensive spectroscopic analysis and chemical evidences. The discovery of the new compounds 1-4 extended the diversity and complexity of this spirostanol saponin family. The saponins 5 and 6 exhibited cytotoxicities against two human glioma cell lines.
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Thermally activated delayed fluorescence (TADF) from linear two-coordinate coinage metal complexes is sensitive to the geometric arrangement of the ligands. Herein we realize the tuning of configuration from coplanar to orthogonal gradually by variation of substituents. In a complex with confined twist configuration, its blue emission peaking at 458â nm presents a high ΦPL of 0.74 and a short τTADF of 1.9 µs, which indicates a fast enough kr,TADF of 3.9×105 â s-1 and a depressed knr of 1.4×105 â s-1 . Such outstanding luminescent properties are attributed to the proper overlap of HOMO and LUMO on CuI d orbitals that guarantees not only small ΔEST but also sufficient transition oscillator strength for fast k r , S 1 ${{k}_{{\rm r},{{\rm S}}_{1}}}$ . Vacuum-deposited blue OLEDs with either doped or host-free emissive layer present external quantum efficiencies over 20 % and 10 %, respectively, demonstrating the practicality of the configurationally confined strategy for efficient linear CuI TADF emitters.
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The chemical constituent investigation on the root bark of Ailanthus altissima leads to the isolation of a new ß-carboline alkaloid, 14(S),15-dihydroxy-6-methoxy-ß-carboline (1), along with nine known alkaloids. The structure of new compound was elucidated on basis of extensive spectroscopic analysis, especially two-dimensional (2D) NMR techniques and the absolute configuration of C-14 was determined by ECD calculation. The neuroprotective effect of the isolated compounds on PC12 cells against the serum deprivation injury was evaluated by MTT method. As a result, compound 7 revealed protective effect on PC12 cells and the cell survival rate was significantly increased.
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Phytochemical investigation on the rhizomes of Paris fargesii var. petiolata (Baker ex C. H. Wright) Wang et Tang led to the isolation of five previously undescribed steroidal saponins, parpetiosides A-E (1-5), and six known analogs (6-11). Their structures were established by extensive spectroscopic data analysis and chemical methods. Compound 5 was a rare steroidal saponin with disaccharide moiety linked at C-26 of dehydrokryptogenin that was hardly seen in the genus Paris. The cytotoxicities of the isolated compounds against three human cancer cell lines (U87, HepG2 and SGC-7901) were evaluated, and compound 1 displayed certain inhibitory effect with IC50 values of 8.02 ± 0.45, 8.24 ± 0.57 and 6.20 ± 0.79 µM, respectively. Moreover, the preliminary mechanism of 1 inhibiting the proliferation of the three cancer cell lines might be related to cell cycle distribution and the induction of S phase arrest.
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Antineoplásicos , Liliaceae , Neoplasias , Saponinas , Humanos , Rizoma/química , Antineoplásicos/farmacología , Antineoplásicos/análisis , Liliaceae/química , Esteroides/farmacología , Esteroides/química , Saponinas/farmacología , Saponinas/químicaRESUMEN
Aiming at the complex structure, small output displacement, and low positioning accuracy of the two-degree-of-freedom (2-DOF) precision positioning platform, theoretical analyses and experimental tests are carried out so that the platform has the characteristics of compact structure, large output stroke, and high positioning accuracy. First, to optimize the structural parameters of the positioning platform, a modeling method to improve the modeling accuracy of the compliant mechanism of the positioning platform is proposed. A static model of the positioning platform based on Euler-Bernoulli beam theory and the sixth-order compliance matrix method is established, and the accuracy of the model is verified by simulation. In addition, the single-objective genetic optimization algorithm is used to optimize the structural size parameters of the positioning platform, and the optimal solution set of the structural size parameters of the positioning platform is obtained by taking the displacement amplification rate of the positioning platform as the optimization target. Finally, according to theoretical and simulation analysis and optimization results, an experimental prototype was fabricated, and a series of experimental tests were carried out on the working stroke, displacement magnification, and output stiffness. The experimental results show that the displacement magnification of the positioning platform reaches 3.39, the positioning stroke is 89.2 × 85.9 µm2, and the displacement resolutions of the x-axis and y-axis are 35 and 31 nm, respectively. The positioning platform designed in this paper meets the requirements of large output stroke and high positioning accuracy.
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Accidente Cerebrovascular , Humanos , Simulación por ComputadorRESUMEN
Urolithin A (UA) is a metabolite produced in the gut following the consumption of ellagic acid (EA) rich foods. EA has shown anti-inflammatory, antioxidant, and anticancer properties. Because EA is poorly absorbed in the gastrointestinal tract, urolithins are considered to play a major role in bioactivity. Helicobacter pylori (H. pylori) infection is the most common chronic bacterial infection all over the world. It is potentially hazardous to humans because of its relationship to various gastrointestinal diseases. In this study, we investigated the effect of UA on inflammation by H. pylori. The results indicated that UA attenuated H. pylori-induced inflammation in vitro and in vivo. UA also reduced the secretion of H. pylori virulence factors and tissue injuries in mice. Furthermore, UA decreased the relative abundance of Helicobacteraceae in feces of H. pylori-infected mice. In summary, taking UA effectively inhibited the injury caused by H. pylori.
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Infecciones por Helicobacter , Helicobacter pylori , Animales , Antioxidantes/farmacología , Cumarinas/farmacología , Ácido Elágico/metabolismo , Infecciones por Helicobacter/tratamiento farmacológico , Humanos , Inflamación , Ratones , Factores de VirulenciaRESUMEN
Light hydrocarbons (LHs) separation is an important process in petrochemical industry. The current separation technology predominantly relies on cryogenic distillation, which results in considerable energy consumption. Adsorptive separation using porous solids has received widespread attention due to its lower energy footprint and higher efficiency. Thus, tremendous efforts have been devoted to the design and synthesis of high-performance porous solids. Among them, porous carbons display exceptional stability, tunable pore structure, and surface chemistry and thus represent a class of novel adsorbents upon achieving the matched pore structures for LHs separations. In this review, the modulation strategies toward advanced carbon-based adsorbents for LHs separation are firstly reviewed. Then, the relationships between separation performances and key structural parameters of carbon adsorbents are discussed by exemplifying specific separation cases. The research findings on the control of the pore structures as well as the quantification of the adsorption sites are highlighted. Finally, the challenges of carbonaceous adsorbents facing for LHs separation are given, which would motivate us to rationally design more efficient absorbents and separation processes in future.
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Highly responsive organic photodetectors allow a plethora of applications in fields like imaging, health, security monitoring, etc. Photomultiplication-type organic photodetectors (PM-OPDs) are a desirable option due to their internal amplification mechanism. However, for such devices, significant gain and low dark currents are often mutually excluded since large operation voltages often induce high shot noise. Here, a fully vacuum-processed PM-OPD is demonstrated using trap-assisted electron injection in BDP-OMe:C60 material system. By applying only -1 V, compared with the self-powered working condition, the responsivity is increased by one order of magnitude, resulting in an outstanding specific detectivity of ≈1013 Jones. Remarkably, the superior detectivity in the near-infrared region is stable and almost voltage-independent up to -10 V. Compared with two photovoltaic-type photodetectors, these PM-OPDs exhibit the great potential to be easily integrated with state-of-the-art readout electronics in terms of their high responsivity, fast response speed, and bias-independent specific detectivity. The employed vacuum fabrication process and the easy-to-adapt PM-OPD concept enable seamless upscaling of production, paving the way to a commercially relevant photodetector technology.
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ElectrónicaRESUMEN
OBJECTIVES: This study aimed to clarify the characteristics of Tn7-derivatives transposons in MDR Proteus mirabilis strains isolated from anal swabs of chicken and swine in China from 2015-2020. METHODS: The Tn7 tnsA gene was screened in 207 P. mirabilis isolates by polymerase chain reaction (PCR). These strains were subjected to antimicrobial susceptibility testing. Illumina Hiseq (200 × coverage) was used for genome sequencing. Transposon maps were completed by PCR and Sanger sequencing and analysed by BLAST. RESULTS: The Tn7 tnsA gene was detected in 21 strains by PCR. Eight novel Tn7-derivatives, named Tn6667, Tn6668, Tn6669, Tn6670, Tn7095, Tn7096, Tn7097 and Tn7098, were characterised. Three types of hybrid class 2/1 integrons were found at the right end of Tn7 derivatives. A novel Tn7-like transposon Tn6666 with an active integrase gene intI2, whose transposition module shows 93% nucleotide identity to the corresponding region of Tn7, was characterised in three strains. Tn6666 is also found next to Tn7097 or Tn7098 in the chromosomes of two clonally related P. mirabilis strains. The number of resistance genes carried by the novel transposons varied from 1 to 18. A novel variant of class A extended-spectrum beta-lactamase gene, blaPER-16, with eight base substitutions compared with blaPER-12, was harboured by Tn7098. CONCLUSION: Our study characterised diverse novel Tn7-derivatives and a new Tn7-like transposon in P. mirabilis. An active integrase gene intI2 might promote the diversification of Tn7-like transposons. More attention should be paid to the prevalence and evolution of Tn7-derivatives and Tn7-like transposons and antimicrobial resistance genes they carry.
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Integrones , Proteus mirabilis , Animales , Pollos , China , Integrasas , Integrones/genética , Proteus mirabilis/genética , PorcinosRESUMEN
The emergence of the phenicol-oxazolidinone-tetracycline resistance gene poxtA becomes a significant challenge for public health, since it confers a decreased susceptibility not only to the last resort drug linezolid, but also to florfenicol and doxycycline widely used in veterinary medicine. To determine the dissemination mechanism of poxtA in enterococci isolates from different healthy pigs in the swine farm, a total of 178 florfenicol-resistant enterococci isolates were collected from 400 fresh faecal swabs in a swine farm in China. The poxtA gene was detected in 11 (6.18 %) enterococci isolates, including 8 E. faecium, 2 E. hirae and 1 E. casseliflavus isolates. Whole genome sequencing indicated that the eight poxtA-harbouring E. faecium strains belonged to four different sequence types, including ST156 and three new STs, ST1818, ST1819 and ST1820. Five out of the 11 poxtA-positive enterococci isolates also harboured optrA gene. Moreover, E. casseliflavus strain DY31 co-harboured poxtA, optrA and cfr. Seven different poxtA-harbouring plasmids were obtained through Nanopore combined with Illumina sequencing. The poxtA-harbouring plasmids exhibited high genetic variation, six out of which belonged to rep2 plasmid of Inc18 family. The poxtA gene was flanked by IS1216E in the left and/or right ends.The optrA and cfr genes were located on different plasmids, respectively, but those genes could be co-transferred with poxtA gene into the recipient E. faecalis strain by electrotransformation. Our study highlights that both clonal spread and horizontal transfer mediated by Inc18 plasmid and IS1216E promote the dissemination of poxtA in enterococci isolates from different healthy pigs in the swine farm.
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Enterococcaceae , Enterococcus faecium , Transferencia de Gen Horizontal , Infecciones por Bacterias Grampositivas , Oxazolidinonas , Enfermedades de los Porcinos , Resistencia a la Tetraciclina , Animales , Antibacterianos/farmacología , China , Farmacorresistencia Bacteriana/genética , Enterococcaceae/efectos de los fármacos , Enterococcaceae/genética , Enterococcus faecalis/efectos de los fármacos , Enterococcus faecalis/genética , Enterococcus faecium/efectos de los fármacos , Enterococcus faecium/genética , Granjas , Transferencia de Gen Horizontal/genética , Infecciones por Bacterias Grampositivas/epidemiología , Infecciones por Bacterias Grampositivas/microbiología , Infecciones por Bacterias Grampositivas/veterinaria , Pruebas de Sensibilidad Microbiana/veterinaria , Oxazolidinonas/farmacología , Porcinos , Enfermedades de los Porcinos/epidemiología , Resistencia a la Tetraciclina/genéticaRESUMEN
Persistent luminescence from triplet excitons in organic molecules is rare, as fast non-radiative deactivation typically dominates over radiative transitions. This work demonstrates that the substitution of a hydrogen atom in a derivative of phenanthroimidazole with an N-phenyl ring can substantially stabilize the excited state. This stabilization converts an organic material without phosphorescence emission into a molecular system exhibiting efficient and ultralong afterglow phosphorescence at room temperature. Results from systematic photophysical investigations, kinetic modeling, excited-state dynamic modeling, and single-crystal structure analysis identify that the long-lived triplets originate from a reduction of intrinsic non-radiative molecular relaxations. Further modification of the N-phenyl ring with halogen atoms affects the afterglow lifetime and quantum yield. As a proof-of-concept, an anticounterfeiting device is demonstrated with a time-dependent Morse code feature for data encryption based on these emitters. A fundamental design principle is outlined to achieve long-lived and emissive triplet states by suppressing intrinsic non-radiative relaxations in the form of molecular vibrations or rotations.
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OBJECTIVE: To investigate whether Hydrolyzed Seawater Pearl tablet (HSPT) could modulate the Th1/Th2 imbalance in an immunosuppressed mouse model with Th1 to Th2 shift induced by Cyclosporine A (CsA) which can be used in the clinical treatment of Th2 to Th1 shift diseases, and explore the possible mechanism for the adjuvant therapeutic efficacy of HSPT on recurrent respiratory infections (RRI) and acquired immune deficiency syndrome (AIDS). METHODS: The mice were randomly divided into six groups of five animals each, namely normal group, model group, lentinan polysaccharide tablet (LPT) group and three HPST treated groups. HPST treated groups were administered with HPST (0.51, 1.02, 2.04 g/kg) via intragastric gavage (i.g) for 30 consecutive days. LPT used as reference drug for positive control, LPT group was administered with LPT (8.2 mg/kg) for 30 consecutive days. Normal group and model group were received distilled water. The animals in model group, LPT group and HPST treated groups were injected intraperitoneally with CsA (50 mg/kg) to establish the immunosuppressed mice model with Th1 to Th2 shift on the 20th, 22nd and 24th day, one hour after the administration of the respective treatment. Animals were sacrificed one hour after the last administration to collect blood and splenic tissue. The proportion of T cells including CD8+ and CD4+ T cells, Th1 and Th2 in peripheral blood of experimental mice were measured by flow cytometric. The protein level in serum and mRNA level in splenic tissue of experimental mice for interleukin (IL)-2, IL-12, interferon-γ (IFN-γ), IL-4, IL-6, IL-10 and IL-13 were measured by enzyme linked immunosorbent assay and fluorescence quantitative polymerase chain reaction respectively. RESULTS: HSPT elevated the proportion of T cells including both CD8+ and CD4+ T cells, in which the proportion of Th1 and Th2 cells increased, while the ratio of Th1/Th2 cells decreased in peripheral blood of the immunosuppressed mouse model with Th1 to Th2 shift induced by CsA. Furthermore, HSPT elevated both protein and mRNA level of Th1-type cytokines IL-2 and IFN-γ, while had no significant effect on protein and mRNA level of Th1-type cytokine IL-12 and Th2-type cytokines IL-4, IL-6, IL-10, IL- 13 in mouse model. CONCLUSION: Our findings suggest that HSPT can increase proportion of T cells including both CD8+ and CD4+ T cells and induce Th2 to Th1 shift in both cells and cytokines, which probably was the mechanism to account for the adjuvant therapeutic efficacy of HSPT on RRI and AIDS.
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Células TH1 , Células Th2 , Animales , Citocinas , Interferón gamma , Ratones , Agua de Mar , ComprimidosRESUMEN
A luminescent bimetallic AuI complex comprised of N-heterocyclic carbene (NHC) and carbazole (Cz) ligands, that is, (NHC')Au(NHC)AuCz has been synthesized and studied. Both carbene ligands in the bimetallic complex act as electron acceptors in tandem to increase the energy separation between the ground and excited state, which is higher than those found in either monometallic analogue, (NHC)AuCz and (NHC')AuCz. A coplanar geometry designed into the tandem complex ensures sufficient electronic coupling between the π-orbitals of the ligands to impart a strong oscillator strength to the singlet intra-ligand charge-transfer (1 ICT) transition. Theoretical modelling indicates that the emissive ICT excited state involves both NHC ligands. The tandem complex gives blue luminescence (λmax =480â nm) with a high photoluminescent quantum yield (ΦPL =0.80) with a short decay lifetime (τ=0.52â µs). Temperature-dependent photophysical studies indicate that emission is via thermally assisted delayed fluorescence (TADF) and give a small singlet-triplet energy difference (ΔEST =50â meV, 400â cm-1 ) consistent with the short TADF lifetime.
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OBJECTIVE: This study aimed to assess the effect and mechanism of i-type lysozyme on cutaneous wound healing animal model and Multiple cell models both in vivo and in vitro. METHODS: Therefore, to evaluate its regenerative efficacy on wound healing process, we daily applied i-type lysozyme on murine full-thickness excisional wounds. After sacrifice on indicated days, skin tissues around surgical defects were harvested and assessed for re-epithelialization, granulation tissue formation, neovascularization and remodeling. To elucidate the underlying mechanisms, i-type lysozyme was analyzed for its tissue regenerative potency on the proliferation, invasion, migration and tube formation against keratinocytes, fibroblasts and endothelial cells. Antioxidant and antimicrobial experiments were also conducted to elucidate protective ability of i-type lysozyme to wound bed. RESULTS: It displayed excellent bi-directional regulation in wound repair, with significant acceleration of epidermal and dermal regeneration as well as the efficient attenuation of excessive collagen deposition and fibrosis in the surgical lesion. I-type lysozyme treatment augmented the proliferation and migration of HaCaT, NIH 3T3 and HUVECs, enhanced the invasion of HaCaT and HUVECs as well as accelerated tube formation of HUVECs. Additionally, it significantly recovered the proliferation of H2O2-damaged cells, whereas represented no microbicidal effect under effective concentration of wound healing. CONCLUSION: Our findings demonstrate the bi-directional regulation of i-type lysozyme in wound healing process through promoting tissue regeneration while hampering scar formation, implying that it is a promising therapeutic agent for wound repair.
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Muramidasa/farmacología , Cicatrización de Heridas/efectos de los fármacos , Animales , Movimiento Celular/efectos de los fármacos , Colágeno/metabolismo , Células HaCaT , Células Endoteliales de la Vena Umbilical Humana , Humanos , Queratinocitos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Células 3T3 NIH , Repitelización/efectos de los fármacos , Regeneración/efectos de los fármacos , Cicatrización de Heridas/fisiologíaRESUMEN
RATIONALE: Vitamin D-dependent rickets type I (VDDR-I) is a rare form of rickets, which is an autosomal recessive disease caused by 1α-hydroxylase enzyme deficiency. However, long-term dental management and microscopic morphology of teeth remain largely unclear. PATIENT CONCERNS: We report the case of a 10-year-old Chinese boy complaining of yellowish-brown teeth with extensive caries. DIAGNOSES: Clinical and laboratory examinations were performed, and VDDR-I was confirmed. Scanning electron microscopy confirmed amelogenesis imperfecta. INTERVENTIONS: The patient had been taking drugs intervention for VDDR-I from the age of 3 years. The decayed teeth were treated, and metal-preformed crowns were placed to prevent further impairment. Sequence tooth extraction and remineralization therapy were also performed. OUTCOMES: After 3 years of follow-up, the patient exhibited normal tooth replacement and an acceptable oral hygiene status. However, the new erupted teeth had amelogenesis imperfecta. LESSONS: This case is the first to confirm amelogenesis imperfecta in a patient with VDDR-I that was not prevented by drug intervention. Importantly, it provides evidence that long-term dental intervention in patients with VDDR-I can result in an acceptable oral hygiene status. Therefore, early and long-term dental intervention is necessary in VDDR-I patients.