Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 115
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
J Am Chem Soc ; 146(10): 7105-7115, 2024 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-38417151

RESUMO

The binding of nucleotides is crucial for signal transduction as it induces conformational protein changes, leading to downstream cellular responses. Synthetic receptors that bind nucleotides and transduce the binding event into global conformational rearrangements are highly challenging to design, especially those that operate in an aqueous solution. Much work is focused on evaluating functionalized dyes to detect nucleotides, whereas coupling of a nucleotide-induced conformational switching to a sensing event has not been reported to date. We disclose synthetic receptors that undergo a global conformational rearrangement upon nucleotide binding. Integrating naphthalimide and the pyridinium ion into the structure enables stabilization of the folded conformation and efficient fluorescence quenching. The binding of a nucleotide rearranges the receptor conformation and alters the strong fluorescence enhancement. The methylpyridinium-containing receptor demonstrated high sensing selectivity for adenosine 5'-triphosphate (ATP) and a record 160-fold fluorescence enhancement. It can detect fluctuations of ATP in HeLa cells and possesses low cytotoxicity. The developed systems present an attractive approach for designing ATP-responsive artificial molecular switches that operate in water and integrate a strong fluorescence response.


Assuntos
Trifosfato de Adenosina , Receptores Artificiais , Humanos , Trifosfato de Adenosina/química , Fluorescência , Células HeLa , Nucleotídeos/metabolismo , Tomografia por Emissão de Pósitrons , Espectrometria de Fluorescência , Conformação Proteica , Corantes Fluorescentes/química , Difosfato de Adenosina/metabolismo
2.
Small ; 20(24): e2306738, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38161257

RESUMO

Adoptive immunotherapy utilizing natural killer (NK) cells has demonstrated remarkable efficacy in treating hematologic malignancies. However, its clinical intervention for solid tumors is hindered by the limited expression of tumor-specific antigens. Herein, lipid-PEG conjugated hyaluronic acid (HA) materials (HA-PEG-Lipid) for the simple ex-vivo surface coating of NK cells is developed for 1) lipid-mediated cellular membrane anchoring via hydrophobic interaction and thereby 2) sufficient presentation of the CD44 ligand (i.e., HA) onto NK cells for cancer targeting, without the need for genetic manipulation. Membrane-engineered NK cells can selectively recognize CD44-overexpressing cancer cells through HA-CD44 affinity and subsequently induce in situ activation of NK cells for cancer elimination. Therefore, the surface-engineered NK cells using HA-PEG-Lipid (HANK cells) establish an immune synapse with CD44-overexpressing MIA PaCa-2 pancreatic cancer cells, triggering the "recognition-activation" mechanism, and ultimately eliminating cancer cells. Moreover, in mouse xenograft tumor models, administrated HANK cells demonstrate significant infiltration into solid tumors, resulting in tumor apoptosis/necrosis and effective suppression of tumor progression and metastasis, as compared to NK cells and gemcitabine. Taken together, the HA-PEG-Lipid biomaterials expedite the treatment of solid tumors by facilitating a sequential recognition-activation mechanism of surface-engineered HANK cells, suggesting a promising approach for NK cell-mediated immunotherapy.


Assuntos
Receptores de Hialuronatos , Ácido Hialurônico , Imunoterapia , Células Matadoras Naturais , Células Matadoras Naturais/imunologia , Receptores de Hialuronatos/metabolismo , Animais , Humanos , Imunoterapia/métodos , Ácido Hialurônico/química , Linhagem Celular Tumoral , Ligantes , Camundongos , Polietilenoglicóis/química , Neoplasias/terapia , Neoplasias/imunologia
3.
Histochem Cell Biol ; 158(6): 595-602, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35857110

RESUMO

Tumor progression is profoundly affected by crosstalk between cancer cells and their stroma. In the past decades, the development of bioinformatics and the establishment of organoid model systems have allowed extensive investigation of the relationship between tumor cells and the tumor microenvironment (TME). However, the interaction between tumor cells and the extracellular matrix (ECM) in odontogenic epithelial neoplasms and the ECM remodeling mechanism remain unclear. In the present study, transcriptomic comparison and histopathologic analysis revealed that TME-related genes were upregulated in ameloblastoma compared to in odontogenic keratocysts. Tumoroid analysis indicated that type I collagen is required for ameloblastoma progression. Furthermore, ameloblastoma shows the capacity to remodel the ECM independently of cancer-associated fibroblasts. In conclusion, ameloblastoma-mediated ECM remodeling contributes to the formation of an invasive collagen architecture during tumor progression.


Assuntos
Colágeno , Microambiente Tumoral
4.
Anal Chem ; 93(44): 14778-14783, 2021 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-34705435

RESUMO

ß-Galactosidase (ß-gal), well known as a useful reporter enzyme, is a potent biomarker for various diseases such as colorectal and ovarian cancers. We have developed a highly stable red-emissive ratiometric fluorescent probe (CCGal1) for quantitatively monitoring the ß-gal enzyme activity in live cells and tissues. This ratiometric probe showed a fast emission color change (620-662 nm) in response to ß-gal selectively, which was accompanied by high enzyme reaction efficacy, cell-staining ability, and outstanding stability with minimized cytotoxicity. Confocal fluorescence microscopy ratiometric images, combined with fluorescence-activated cell sorting flow cytometry, demonstrated that CCGal1 could provide useful information for the diagnosis, prognosis, and treatment of ß-gal enzyme activity-related diseases such as colorectal and ovarian cancers. Further, it may yield meaningful strategies for designing and modifying multifunctional bioprobes with different biomedical applications.


Assuntos
Corantes Fluorescentes , Citometria de Fluxo , Microscopia Confocal , Microscopia de Fluorescência , beta-Galactosidase
5.
Anal Chem ; 93(50): 16821-16827, 2021 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-34886662

RESUMO

Inappropriate cancer management can be prevented by simultaneous cancer diagnosis, treatment, and real-time assessment of therapeutic processes. Here, we describe the design of a two-photon (TP) photosensitizer (PS), ACC-B, for high temporal and spatioselective near-infrared cancer therapy. ACC-B consisting of a biotin unit significantly enhanced the cancer sensitivity of the PS. Upon TP irradiation, ACC-B generated reactive oxygen species (ROS) through the type I photodynamic therapy (PDT) process and triggered highly selective cancer ablation. In addition, fluorescence microscopy images revealed that ACC-B-loaded live human colon tissues showed a marked difference in ACC-B uptake between normal and cancer tissues, and this property was used for real-time imaging. Upon 770 nm TP treatment, ACC-B generated ROS efficiently in live colon cancer tissues with high spatial selectivity. During PDT, ACC-B can provide in situ spatioselective visualization of cellular behavior and molecular information for therapeutic assessment in specific regions.


Assuntos
Neoplasias , Fotoquimioterapia , Compostos Azo , Colo/diagnóstico por imagem , Humanos
6.
Cell Tissue Res ; 386(2): 415-421, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34302527

RESUMO

Different stem cell-based strategies, especially induced pluripotent stem cells (iPSCs), have been exploited to regenerate teeth or restore biological and physiological functions after tooth loss. Further research is needed to establish an optimized protocol to effectively differentiate human iPSCs (hiPSCs) into dental epithelial cells (DECs). In this study, various factors were precisely modulated to facilitate differentiation of hiPSCs into DECs, which are essential for the regeneration of functional teeth. Embryoid bodies (EBs) were formed from hiPSCs as embryo-like aggregates, retinoic acid (RA) was used as an early ectodermal inducer, and bone morphogenic protein 4 (BMP4) activity was manipulated. The characteristics of DECs were enhanced and preserved after culture in keratinocyte serum-free medium (K-SFM). The yielded cell population exhibited noticeable DEC characteristics, consistent with the expression of epithelial cell and ameloblast markers. DECs demonstrated odontogenic abilities by exerting an inductive effect on human dental pulp stem cells (hDPSCs) and forming a tooth-like structure with the mouse tooth mesenchyme. Overall, our differentiation protocol provides a practical approach for applying hiPSCs for tooth regeneration.


Assuntos
Células Epiteliais/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Dente/citologia , Diferenciação Celular , Linhagem Celular , Linhagem da Célula , Humanos , Odontogênese , Dente/crescimento & desenvolvimento
7.
Biochem Biophys Res Commun ; 511(3): 637-643, 2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30826055

RESUMO

Metabolic bone diseases are global public health concerns and are primarily caused by uncontrolled osteoclast (OC) formation and activation. During OC differentiation, intracellular reactive oxygen species (ROS) stimulated by receptor activator of nuclear factor kappa-B ligand (RANKL) can serve as the signaling molecules to promote osteoclastic genes expression. Nuclear factor erythroid-2 related factor 2 (NRF2), a master mediator of cellular antioxidant response, also plays a critical role in OC differentiation through the regulation of redox homeostasis. In this study, we investigated the effects of three NRF2 inducers on osteoclastogenesis, including Bardoxolone methyl (CDDO-Me), Sulforaphane (SFN), and tert-butylhydroquinone (tBHQ). By treating RAW cells with three compounds, we found that NRF2 was activated and its downstream antioxidant genes were upregulated, and the RANKL-induced intracellular ROS production and osteoclastogenesis were impaired. Additionally, the expression of nuclear factor of activated T cells c1 (NFATC1), C-FOS and tumor necrosis factor alpha (TNFα) were inhibited after acute exposures (6 h) to the three compounds. Furthermore, suppressed the expression of osteoclast differentiation-associated genes, tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), matrix metalloproteinase-9 (MMP-9) and dendritic cell-specific transmembrane protein (DC-STAMP) were observed after prolonged exposures (5 days) to the compounds. Taken together, these results suggest that CDDO-Me, SFN and tBHQ attenuate RANKL-induced osteoclastogenesis via activation of NRF2-mediated antioxidant response. Among these compounds, relatively low concentrations of CDDO-Me showed stronger active and inhibitory effects on antioxidant response and osteoclastogenesis, respectively.


Assuntos
Antioxidantes/farmacologia , Hidroquinonas/farmacologia , Isotiocianatos/farmacologia , Ácido Oleanólico/análogos & derivados , Osteogênese/efeitos dos fármacos , Ligante RANK/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Células Cultivadas , Masculino , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/metabolismo , Ácido Oleanólico/farmacologia , Osteoclastos/citologia , Osteoclastos/efeitos dos fármacos , Osteoclastos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sulfóxidos
8.
Histochem Cell Biol ; 151(3): 229-238, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30392058

RESUMO

The skin wound healing ability of animals differs depending on the environment. The gerbil wound model showed a different wound healing mechanism than was known thus far. Many other wound healing mechanisms have been found to involve transforming growth factor-beta 1 (TGF-ß1). However, in the wound healing of gerbil skin, the expression of TGF-ß1 seems to be not enough compared to mouse. In this study, we compared the wound healing process of gerbil and mouse back skin. At 3 days after wounding, the TGF-ß1 level was downregulated in gerbil skin wound healing compared mouse. In addition, gerbils have fewer integrin signals related to the regulation of TGF-ß activation and signaling. Despite lacking these factors, the wound healing results in the gerbil are similar to those for skin wound healing in mice. In contrast, in gerbil skin wound healing, the basal skin layer showed hyperplasia in re-epithelialization, more production of hair follicles, and low probability of collagen infiltration at the late stages of wound healing. These data suggest that different wound healing mechanisms are present in the mammals.


Assuntos
Gerbillinae/metabolismo , Pele/metabolismo , Cicatrização , Animais , Camundongos , Camundongos Endogâmicos ICR , Pele/patologia , Fator de Crescimento Transformador beta1/metabolismo
9.
Orthod Craniofac Res ; 22 Suppl 1: 127-133, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31074145

RESUMO

OBJECTIVE: The pore size of the scaffold is a critical factor in repairing large bone defect. Here, we investigated the potential of bone regeneration using novel nanocomposite polydopamine-laced hydroxyapatite collagen calcium silicate (HCCS-PDA) scaffolds with two different pore sizes, 250 and 500 µm. SAMPLES/SETTING: A total of 12 male Sprague-Dawley rats were implanted with HCCS-PDA scaffold with pore size of either 250 or 500 µm into surgically created critical-sized defect (CSD). METHODS: HCCS-PDA scaffolds were fabricated using mould printing technique. The effect of pore size on mechanical strength of the scaffolds was assessed by compression testing. After seeding with rat mesenchymal stem cells (rMSCs), the scaffolds were implanted, and new bone formation was evaluated using microCT and histomorphometric analysis after 8 weeks. RESULTS: MicroCT and histology analysis demonstrated restricted peripheral new bone formation in either dural or periosteal side and limited new bone formation in the 250 µm pore scaffold. Conversely, the 500-µm pore scaffold showed more penetration of new bone into the scaffold and greater bone regeneration in the rat CSD. CONCLUSION: Based on our results, which demonstrated improved new bone formation in 500 µm pores scaffold, we can conclude that effective scaffold pore size that induces osteointegration and bone regeneration is around 500 µm for HCCS-PDA nanocomposite scaffold.


Assuntos
Cálcio , Durapatita , Animais , Regeneração Óssea , Compostos de Cálcio , Colágeno , Indóis , Masculino , Polímeros , Porosidade , Impressão Tridimensional , Ratos , Ratos Sprague-Dawley , Silicatos , Engenharia Tecidual , Alicerces Teciduais
10.
Clin Oral Investig ; 23(5): 2129-2141, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30269174

RESUMO

OBJECTIVES: To synthesize two different sizes of bioactive glass-coated mesoporous silica nanoparticles (BGN@MSNs) and to investigate their effects on dentinal tubule occlusion and remineralization. MATERIALS AND METHODS: Two different sizes of mesoporous silica nanoparticles (MSNs) were synthesized using the Stöber method (368A, 1840A) and coated with bioactive glass nanoparticles (BGNs) using a modified quick alkali-mediated sol-gel method (368B, 1840B). Sensitive tooth disc models were prepared and divided into six groups and the following treatments were applied: group 1-no treatment, group 2-bioglass, group 3-368A, group 4-368B, group 5-1840A, and group 6-1840B. Then, five discs were selected from each group and soaked in 6 wt% citric acid to test acid resistance. Dentinal tubule occlusion and occlusion ratio were observed using field-emission scanning electron microscopy. In vitro mineralization tests using simulated body fluid solution were performed to evaluate the remineralization effect of the treatment. RESULTS: All samples effectively occluded the dentinal tubule and formed a membrane-like layer. After acid treatment, 1840B (group 6) exhibited the highest rate of dentinal tubule occlusion. Remineralization was observed in 368B and 1840B, and 1840B exhibited the fastest remineralization. CONCLUSIONS: Dentinal tubule remineralization induced by the BGN@MSN biocomposite can be used to stabilize long-term prognosis in dentin hypersensitivity. The 1840B induced the most efficient remineralization, and its smaller size and larger surface area were effective for remineralization. CLINICAL RELEVANCE: The BGN@MSN biocomposite with its smaller size and larger surface area was more effective for remineralization and dentinal tubule sealing.


Assuntos
Dessensibilizantes Dentinários/química , Sensibilidade da Dentina , Nanopartículas/química , Dióxido de Silício/química , Remineralização Dentária , Dentina , Humanos , Microscopia Eletrônica de Varredura , Tamanho da Partícula
11.
Sensors (Basel) ; 19(13)2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31261698

RESUMO

We present the practical resolution limit of a fine electrical structure based on a fiber-coupled electro-optic probing system. The spatial resolution limit was experimentally evaluated on the sub-millimeter to micrometer scale of planar electrical transmission lines. The electrical lines were fabricated to have various potential differences depending on the dimensions and geometry. The electric field between the lines was measured through an electro-optic probe, which was miniaturized up to the optical bare fiber scale so as to investigate the spatial limit of electrical signals with minimal invasiveness. The experimental results show that the technical resolution limitation of a fiber-coupled probe can reasonably approach a fraction of the mode field diameter (~10 µm) of the fiber in use.

12.
Appl Opt ; 56(6): 1701-1707, 2017 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-28234379

RESUMO

We present a magneto-optic sensing system based on the "off-axis" optical probing technique to control the measurement sensitivity of magnets with various field strengths. The magnetic field is experimentally investigated in the absolute scale through a photonic calibration method with a standard electromagnet. Our all-dielectric magnetic field probe has a wide dynamic range (20 mT-3 T) with good responsivity and low probe invasiveness against the magnetic field being measured. Utilizing this magnetic-field-calibrated probing system, we obtain the magnetic field distribution of permanent magnets. Subsequently, we compare our results with numerical analyses to confirm the effectiveness of the probing system. Finally, we measure the intense magnetic field inside the bore of a 3.0-T clinical magnetic resonance imaging system with our probe.

13.
Opt Express ; 24(10): 10547-55, 2016 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-27409877

RESUMO

We present a field-calibrated electro-optic sensing system for measurement of the electric field radiating from a high-power vacuum oscillator at ~95 GHz. The intense electric field is measured in absolute scale via two probe-calibration steps, associated with a photonic heterodyne scheme. First, a micro-electro-optic probe, fabricated to less than one-tenth the oscillation wavelength scale to minimize field-perturbation due to the probe, is placed on the aperture of a field-calculable WR-10 waveguide to calibrate the probe in V/m scale. Then, using this arrangement as a calibrated reference probe at the first-tier position, another probe-bulkier, and thus more robust and sensitive but not accessible to the aperture-is calibrated at the second-tier position away from the waveguide aperture. This two-tier calibrated probe was utilized to diagnose the sub-MV/m scale of intense electric fields and emissions from a high-power W-band gyrotron. The experimental results obtained proved consistent with calculated analytical results-verifying the efficacy of the developed system.

14.
Histochem Cell Biol ; 144(3): 273-9, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26126650

RESUMO

Gastrin-releasing peptide (GRP) is considered to be one of the cancer growth factors. This peptide's receptor (GRPR) is known as a G protein-coupled receptor, regulating intracellular calcium storage and releasing signals. This study is the first to investigate the function of GRP during mouse incisor development. We hypothesized that GRP is one of the factors that affects the regulation of calcification during tooth development. To verify the expression pattern of GRP, in situ hybridization was processed during incisor development. GRP was expressed at the late bell stage and hard tissue formation stage in the epithelial tissue. To identify the genuine function of GRP during incisor development, a gain-of-function analysis was performed. After GRP overexpression in culture, the phenotype of ameloblasts, odontoblasts and predentin was altered compared to control group. Moreover, enamel and dentin thickness was increased after renal capsule transplantation of GRP-overexpressed incisors. With these results, we suggest that GRP plays a significant role in the formation of enamel and dentin by regulating ameloblasts and predentin formation, respectively. Thus, GRP signaling is strongly related to calcium acquisition and secretion during mouse incisor development.


Assuntos
Calcificação Fisiológica/genética , Peptídeo Liberador de Gastrina/genética , Peptídeo Liberador de Gastrina/fisiologia , Incisivo/crescimento & desenvolvimento , Ameloblastos/fisiologia , Animais , Células Cultivadas , Esmalte Dentário/metabolismo , Dentina/metabolismo , Células Epiteliais/fisiologia , Vetores Genéticos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos ICR , Odontoblastos/fisiologia , Odontogênese/genética
15.
J Mater Sci Mater Med ; 26(2): 92, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25649517

RESUMO

Low mechanical strengths and inadequate bioactive material-tissue interactions of current synthetic materials limit their clinical applications in bone regeneration. Here, we demonstrate gelatin modified siloxane-calcium silicate (GEMOSIL-CS), a nanocomposite made of gelatinous hydroxyapatite with in situ pozzolanic formation of calcium silicate (CS) interacting among gelatin, silica and Calcium Hydroxide (Ca(OH)2). It is shown the formation of CS matrices, which chemically bonds to the gelatinous hydroxyapatite, provided hygroscopic reinforcement mechanism and promoted both in vitro and in vivo osteogenic properties of GEMOSIL-CS. The formation of CS was identified by Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction. The interfacial bindings within nanocomposites were studied by FTIR and thermogravimetric analysis. Both gelatin and CS have been found critical to the structure integrity and mechanical strengths (93 MPa in compressive strength and 58.9 MPa in biaxial strength). The GEMOSIL-CS was biocompatible and osteoconductive as result of type I collagen secretion and mineralized nodule formation from MC3T3 osteoblasts. SEM and TEM indicated the secretion of collagen fibers and mineral particles as the evidence of mineralization in the early stage of osteogenic differentiation. In vivo bone formation capability was performed by implanting GEMOSIL-CS into rat calvarial defects for 12 weeks and the result showed comparable new bone formation between GEMOSIL-CS group (20%) and the control (20.19%). The major advantage of GEMOSIL-CS composites is in situ self-hardening in ambient or aqueous environment at room temperature providing a simple, fast and cheap method to produce porous scaffolds.


Assuntos
Substitutos Ósseos/química , Compostos de Cálcio/química , Durapatita/química , Nanocompostos/química , Silicatos/química , Células 3T3 , Animais , Fenômenos Biofísicos , Regeneração Óssea , Gelatina/química , Masculino , Teste de Materiais , Camundongos , Microscopia Eletrônica , Nanocompostos/ultraestrutura , Osteogênese , Ratos , Ratos Sprague-Dawley , Siloxanas/química , Crânio/lesões , Crânio/fisiopatologia , Crânio/cirurgia , Espectroscopia de Infravermelho com Transformada de Fourier , Alicerces Teciduais/química , Difração de Raios X
16.
Opt Express ; 22(22): 27542-52, 2014 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-25401901

RESUMO

Visualizing the electromagnetic field transformation inside a microwave mode conversion region has been considered to be only realizable by simulation studies. For the first time, we present a comprehensive experimental observation of the electric field transformation occurring inside a metallic waveguide TE(01)-to-TE(02) mode converter. An efficient electro-optic (EO) probe and its associated probing system were used for measuring the electric field pattern in the external near-field region as well as in the internal and penetrated region of the mode converter. Utilizing the optically measured field patterns at the aperture of the mode converter, the conversion performance from the TE(01) mode to the TE(02) mode can be also evaluated. Experimentally measured field patterns near the apertures show excellent agreement with simulation data. The mode conversion to the next higher-order mode (TE(01) to TE(02)) was experimentally demonstrated with phase-stabilized and field-animated post processing. The presented in situ endoscopic photonic measurement technique for the field evolution inside a semi-enclosed structure could be used for visually inspecting manufacturing errors in fabricated structures, and could be of great interest for research on higher-order mode formation and transmission.

17.
Opt Express ; 22(3): 2897-909, 2014 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-24663582

RESUMO

We numerically and experimentally investigate the field invasiveness of microwave signals using an electro-optic technique. The distortion of the standing wave voltage and pulse waveform probed by the electro-optic technique is explored through both minimally invasive external and non-invasive internal sensing configurations. First, we analyzed the continuous wave microwave field imaging on a millimeter- scale coaxial transmission line using a highly accurate and stable electro- optic scanning system. The electric field images from the microwave device are attained virtually non-invasively using a miniaturized fiber-coupled electro-optic probe. The accuracy of the field imaging associated with various probe styles is investigated by numerical analysis and experiment. Then, we analyzed the waveform of the coaxial transmission line up to 50 GHz using a pulsed electro-optic system with an external probe set. Finally, the invasive analysis was extended to the sub-millimeter-scale on-wafer coplanar waveguides, where the voltage waveforms are measured using a minimally invasive external probe as well as an internal wafer probe for non-invasive sampling.


Assuntos
Condutometria/instrumentação , Tecnologia de Fibra Óptica/instrumentação , Micro-Ondas , Radiometria/instrumentação , Refratometria/instrumentação , Transdutores , Desenho de Equipamento , Análise de Falha de Equipamento
18.
Sci Rep ; 14(1): 2602, 2024 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-38297106

RESUMO

Based on anti-inflammatory and osteogenic properties of hesperidin (HE), we hypothesized its systemic administration could be a cost-effective method of improving BMP-induced bone regeneration. Sprague-Dawley rats were allocated into 4 groups (n = 10/group): a 5-mm critical-sized mandible defect + collagen scaffold or, scaffold + 1 µg of BMP2 with and without dietary HE at 100 mg/kg. HE was administered by oral gavage 4 weeks prior to surgeries until euthanasia at day 7 or 14 post-surgery. The healing tissue within the defect collected at day 7 was subjected to gene expression analysis. Mandibles harvested at day 14 were subjected to microcomputed tomography and histology. HE + BMP2-treated rats had a statistically significant decrease in expression of inflammatory genes compared to BMP2 alone. The high-dose BMP2 alone caused cystic-like regeneration with incomplete defect closure. HE + BMP2 showed virtually complete bone fusion. Collagen fibril birefringence pattern (red color) under polarized light indicated high organization in BMP2-induced newly formed bone (NFB) in HE-supplemented group (p < 0.05). Clear changes in osteocyte lacunae as well as a statistically significant increase in osteoclasts were found around NFB in HE-treated rats. A significant increase in trabecular volume and thickness, and trabecular and cortical density was found in femurs of HE-supplemented rats (p < 0.05). Our findings show, for the first time, that dietary HE has a remarkable modulatory role in the function of locally delivered high-dose BMP2 in bone regeneration possibly via control of inflammation, osteogenesis, changes in osteocyte and osteoclast function and collagen maturation in regenerated and native bone. In conclusion, HE had a significant skeletal bone sparing effect and the ability to provide a more effective BMP-induced craniofacial regeneration.


Assuntos
Hesperidina , Ratos , Animais , Ratos Sprague-Dawley , Hesperidina/farmacologia , Microtomografia por Raio-X , Regeneração Óssea , Osteogênese , Proteína Morfogenética Óssea 2/farmacologia , Proteína Morfogenética Óssea 2/genética , Colágeno/farmacologia , Inflamação
19.
Exp Mol Med ; 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38945953

RESUMO

The asymmetric division of stem cells permits the maintenance of the cell population and differentiation for harmonious progress. Developing mouse incisors allows inspection of the role of the stem cell niche to provide specific insights into essential developmental phases. Microtubule-associated serine/threonine kinase family member 4 (Mast4) knockout (KO) mice showed abnormal incisor development with low hardness, as the size of the apical bud was decreased and preameloblasts were shifted to the apical side, resulting in amelogenesis imperfecta. In addition, Mast4 KO incisors showed abnormal enamel maturation, and stem cell maintenance was inhibited as amelogenesis was accelerated with Wnt signal downregulation. Distal-Less Homeobox 3 (DLX3), a critical factor in tooth amelogenesis, is considered to be responsible for the development of amelogenesis imperfecta in humans. MAST4 directly binds to DLX3 and induces phosphorylation at three residues within the nuclear localization site (NLS) that promotes the nuclear translocation of DLX3. MAST4-mediated phosphorylation of DLX3 ultimately controls the transcription of DLX3 target genes, which are carbonic anhydrase and ion transporter genes involved in the pH regulation process during ameloblast maturation. Taken together, our data reveal a novel role for MAST4 as a critical regulator of the entire amelogenesis process through its control of Wnt signaling and DLX3 transcriptional activity.

20.
Mater Today Bio ; 26: 101050, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38654935

RESUMO

Periodontal ligament (PDL) cells play a crucial role in maintaining periodontal integrity and function by providing cell sources for ligament regeneration. While biophysical stimulation is known to regulate cell behaviors and functions, its impact on epigenetics of PDL cells has not yet been elucidated. Here, we aimed to investigate the cytoskeletal changes, epigenetic modifications, and lineage commitment of PDL cells following the application of stretch stimuli to PDL. PDL cells were subjected to stretching (0.1 Hz, 10 %). Subsequently, changes in focal adhesion, tubulin, and histone modification were observed. The survival ability in inflammatory conditions was also evaluated. Furthermore, using a rat hypo-occlusion model, we verified whether these phenomena are observed in vivo. Stretched PDL cells showed maximal histone 3 acetylation (H3Ace) at 2 h, aligning perpendicularly to the stretch direction. RNA sequencing revealed stretching altered gene sets related to mechanotransduction, histone modification, reactive oxygen species (ROS) metabolism, and differentiation. We further found that anchorage, cell elongation, and actin/microtubule acetylation were highly upregulated with mechanosensitive chromatin remodelers such as H3Ace and histone H3 trimethyl lysine 9 (H3K9me3) adopting euchromatin status. Inhibitor studies showed mechanotransduction-mediated chromatin modification alters PDL cells behaviors. Stretched PDL cells displayed enhanced survival against bacterial toxin (C12-HSL) or ROS (H2O2) attack. Furthermore, cyclic stretch priming enhanced the osteoclast and osteoblast differentiation potential of PDL cells, as evidenced by upregulation of lineage-specific genes. In vivo, PDL cells from normally loaded teeth displayed an elongated morphology and higher levels of H3Ace compared to PDL cells with hypo-occlusion, where mechanical stimulus is removed. Overall, these data strongly link external physical forces to subsequent mechanotransduction and epigenetic changes, impacting gene expression and multiple cellular behaviors, providing important implications in cell biology and tissue regeneration.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA