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1.
Nat Chem Biol ; 18(4): 385-393, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35177837

RESUMO

Cell-free biosensors are powerful platforms for monitoring human and environmental health. Here, we expand their capabilities by interfacing them with toehold-mediated strand displacement circuits, a dynamic DNA nanotechnology that enables molecular computation through programmable interactions between nucleic acid strands. We develop design rules for interfacing a small molecule sensing platform called ROSALIND with toehold-mediated strand displacement to construct hybrid RNA-DNA circuits that allow fine-tuning of reaction kinetics. We use these design rules to build 12 different circuits that implement a range of logic functions (NOT, OR, AND, IMPLY, NOR, NIMPLY, NAND). Finally, we demonstrate a circuit that acts like an analog-to-digital converter to create a series of binary outputs that encode the concentration range of the molecule being detected. We believe this work establishes a pathway to create 'smart' diagnostics that use molecular computations to enhance the speed and utility of biosensors.


Assuntos
Técnicas Biossensoriais , DNA , DNA/metabolismo , Humanos , Nanotecnologia , RNA , Recombinação Genética
2.
J Nanosci Nanotechnol ; 18(2): 1323-1326, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29448583

RESUMO

In the present work, a facile method for the preparation of nanocomposite adsorbents composed of carbon and iron compounds was demonstrated. The adsorbents were produced by pyrolyzing an iron-coordinated 1,8-diaminonaphthalene at various temperatures under an N2 stream (FeDN X, where X represents the pyrolysis temperatures 600, 700, and 800 °C). Prepared FeDNs were employed as adsorbents for the removal of Cr (VI). The Cr (VI)-adsorption behavior of FeDNs were well-fitted to a Langmuir isotherm model. Among the samples prepared, FeDN 700 showed the best performance for the removal of Cr (VI). In particular, the maximum adsorption capacity of FeDN 700 was evaluated to be 34.81 mg/g. A variety of characterizations were carried out to elucidate the relationship between physical properties of adsorbents and their adsorption behaviors.

3.
Phytother Res ; 31(6): 838-848, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28382688

RESUMO

Epimedii Herba (EH) is an herbal medicine originating from several plants of the genus Epimedium. It is a major therapeutic option for kidney yang deficiency syndrome, which is closely related to androgen hormones and also has been used to treat hemiplegia following a stroke in traditional medicine of Korea and PR China. To date, many clinical and basic researches of EH have shown the activities on functional recovery from brain diseases. Recently, neuroplasticity, which is the spontaneous reaction of the brain in response to diseases, has been shown to accelerate functional recovery. In addition, androgen hormones including testosterone are known to be the representative of neuroplasticity factors in the brain recovery processes. In this review, we described the neuro-pharmacological activities of EH, focusing on neuroplasticity. Thirty-three kinds of papers from MEDLINE/PubMed, EMBASE, and CNKI were identified and analyzed. We categorized the results into five types based on neuroplasticity mechanisms and presented the definition of each category and briefly described the results of these papers. Altogether, we can suggest that neuroplasticity is a novel viewpoint for guiding future brain research of EH and provide the evidence for the development of new clinical applications using EH in the treatment of brain diseases. Copyright © 2017 John Wiley & Sons, Ltd.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Epimedium/química , Plasticidade Neuronal/efeitos dos fármacos , Animais , Encéfalo/efeitos dos fármacos , China , Humanos , Medicina Tradicional Chinesa , Fitoterapia , Plantas Medicinais/química , República da Coreia
4.
JOR Spine ; 7(1): e1297, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38222801

RESUMO

Background: Intervertebral disc degeneration is associated with low back pain, which is a leading cause of disability. While the precise causes of disc degeneration are unknown, inadequate nutrient and metabolite transport through the cartilage endplate (CEP) may be one important factor. Prior work shows that CEP transport properties depend on the porosity of the CEP matrix, but little is known about the role of CEP characteristics that could influence transport properties independently from porosity. Here, we show that CEP transport properties depend on the extent of non-enzymatic glycation of the CEP matrix. Methods and Results: Using in vitro ribosylation to induce non-enzymatic glycation and promote the formation of advanced glycation end products, we found that ribosylation reduced glucose partition coefficients in human cadaveric lumbar CEP tissues by 10.7%, on average, compared with donor- and site-matched CEP tissues that did not undergo ribosylation (p = 0.04). These reductions in glucose uptake were observed in the absence of differences in CEP porosity (p = 0.89) or in the amounts of sulfated glycosaminoglycans (sGAGs, p = 0.47) or collagen (p = 0.61). To investigate whether ribosylation altered electrostatic interactions between fixed charges on the sGAG molecules and the mobile free ions, we measured the charge density in the CEP matrix using equilibrium partitioning of a cationic contrast agent using micro-computed tomography. After contrast enhancement, mean X-ray attenuation was 11.9% lower in the CEP tissues that had undergone ribosylation (p = 0.02), implying the CEP matrix was less negatively charged. Conclusions: Taken together, these findings indicate that non-enzymatic glycation negatively impacts glucose transport in the CEP independent of matrix porosity or sGAG content and that the effects may be mediated by alterations to matrix charge density.

5.
bioRxiv ; 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38712145

RESUMO

Cell-free systems are powerful synthetic biology technologies because of their ability to recapitulate sensing and gene expression without the complications of living cells. Cell-free systems can perform even more advanced functions when genetic circuits are incorporated as information processing components. Here we expand cell-free biosensing by engineering a highly specific isothermal signal amplification circuit called polymerase strand recycling (PSR) that leverages T7 RNA polymerase off-target transcription to recycle nucleic acid inputs within DNA strand displacement circuits. We develop design rules for PSR circuit components and use these rules to construct modular biosensors that can directly sense different RNA targets with limits of detection in the nM range and high specificity. We then use PSR for signal amplification within allosteric transcription factor-based biosensors for small molecule detection. We use a double equilibrium model of transcription factor:DNA and transcription factor:ligand binding interactions to predict biosensor sensitivity enhancement by PSR, and then demonstrate this approach experimentally by achieving 3.6-4.6-fold decreases in biosensor EC50 to sub micromolar ranges. We believe this work expands the current capabilities of cell-free circuits by incorporating PSR, which we anticipate will have a wide range of uses within biotechnology.

6.
bioRxiv ; 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-39005318

RESUMO

Recent years have seen intense interest in the development of point-of-care nucleic acid diagnostic technologies to address the scaling limitations of laboratory-based approaches. Chief among these are combinations of isothermal amplification approaches with CRISPR-based detection and readouts of target products. Here, we contribute to the growing body of rapid, programmable point-of-care pathogen tests by developing and optimizing a one-pot NASBA-Cas13a nucleic acid detection assay. This test uses the isothermal amplification technique NASBA to amplify target viral nucleic acids, followed by Cas13a-based detection of amplified sequences. We first demonstrate an in-house formulation of NASBA that enables optimization of individual NASBA components. We then present design rules for NASBA primer sets and LbuCas13a guide RNAs for fast and sensitive detection of SARS-CoV-2 viral RNA fragments, resulting in 20 - 200 aM sensitivity without any specialized equipment. Finally, we explore the combination of high-throughput assay condition screening with mechanistic ordinary differential equation modeling of the reaction scheme to gain a deeper understanding of the NASBA-Cas13a system. This work presents a framework for developing a mechanistic understanding of reaction performance and optimization that uses both experiments and modeling, which we anticipate will be useful in developing future nucleic acid detection technologies.

7.
Microsc Microanal ; 19 Suppl 5: 210-4, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23920208

RESUMO

The in vitro corrosion mechanism of the biodegradable cast Mg-10% Ca binary alloy in Hanks' solution was evaluated through transmission electron microscopy observations. The corrosion behavior depends strongly on the microstructural peculiarity of Mg2Ca phase surrounding the island-like primary Mg phase and the fast corrosion induced by the interdiffusion of O and Ca via the Mg2Ca phase of lamellar structure. At the corrosion front, we found that a nanosized crack-like pathway was formed along the interface between the Mg2Ca phase and the primary Mg phase. Through the crack-like pathway, O and Ca are atomically exchanged each other and then the corroded Mg2Ca phase was transformed to Mg oxides. The in vitro corrosion by the exchange of Ca and O at the nanosized pathway led to the rapid bulk corrosion in the Mg-Ca alloys.

8.
ACS Synth Biol ; 12(10): 2909-2921, 2023 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-37699423

RESUMO

As the field of synthetic biology expands, the need to grow and train science, technology, engineering, and math (STEM) practitioners is essential. However, the lack of access to hands-on demonstrations has led to inequalities of opportunity and practice. In addition, there is a gap in providing content that enables students to make their own bioengineered systems. To address these challenges, we develop four shelf-stable cell-free biosensing educational modules that work by simply adding water and DNA to freeze-dried crude extracts of non-pathogenic Escherichia coli. We introduce activities and supporting curricula to teach the structure and function of the lac operon, dose-responsive behavior, considerations for biosensor outputs, and a "build-your-own" activity for monitoring environmental contaminants in water. We piloted these modules with K-12 teachers and 130 high-school students in their classrooms─and at home─without professional laboratory equipment. This work promises to catalyze access to interactive synthetic biology education opportunities.


Assuntos
Biologia Sintética , Qualidade da Água , Humanos , Biologia Sintética/educação
9.
Methods Mol Biol ; 2433: 325-342, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34985754

RESUMO

ROSALIND (RNA Output Sensors Activated by Ligand Induction) is an in vitro biosensing system that detects small molecules using regulated transcription reactions. It consists of three key components: (1) RNA polymerases, (2) allosteric protein transcription factors, and (3) synthetic DNA transcription templates that together regulate the synthesis of a fluorescence-activating RNA aptamer. The system can detect a wide range of chemicals including antibiotics, small molecules, and metal ions. We have demonstrated that ROSALIND can be lyophilized and transported at ambient conditions for water testing on-site. Here, we describe how to set up a ROSALIND reaction for detecting various chemical contaminants in water using a model transcription factor as well as how to build a new ROSALIND sensor.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Aptâmeros de Nucleotídeos/química , Metais , RNA/metabolismo , Fatores de Transcrição/metabolismo
10.
Materials (Basel) ; 14(13)2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34279299

RESUMO

The precursor prepared by co-precipitation method was sintered at various temperatures to synthesize crystalline manganese tungstate (MnWO4). Sintered MnWO4 showed the best crystallinity at a sintering temperature of 800 °C. Rare earth ion (Dysprosium; Dy3+) was added when preparing the precursor to enhance the magnetic and luminescent properties of crystalline MnWO4 based on these sintering temperature conditions. As the amount of rare earth ions was changed, the magnetic and luminescent characteristics were enhanced; however, after 0.1 mol.%, the luminescent characteristics decreased due to the concentration quenching phenomenon. In addition, a composite was prepared by mixing MnWO4 powder, with enhanced magnetism and luminescence properties due to the addition of dysprosium, with epoxy. To one of the two prepared composites a magnetic field was applied to induce alignment of the MnWO4 particles. Aligned particles showed stronger luminescence than the composite sample prepared with unsorted particles. As a result of this, it was suggested that it can be used as phosphor and a photosensitizer by utilizing the magnetic and luminescent properties of the synthesized MnWO4 powder with the addition of rare earth ions.

11.
Artigo em Inglês | MEDLINE | ID: mdl-34267944

RESUMO

Tracking progress towards Target 6.1 of the United Nations Sustainable Development Goals, "achieving universal and equitable access to safe and affordable drinking water for all", necessitates the development of simple, inexpensive tools to monitor water quality. The rapidly growing field of synthetic biology has the potential to address this need by taking DNA-encoded sensing elements from nature and reassembling them to create field-deployable 'biosensors' that can detect pathogenic or chemical water contaminants. Here we describe water quality monitoring strategies enabled by synthetic biology and compare them to previous approaches used to detect three priority water contaminants: fecal pathogens, arsenic, and fluoride in order to explain the potential for engineered biosensors to simplify and decentralize water quality monitoring. We also briefly discuss expanding biosensors to detect emerging contaminants including metals and pharmaceuticals. We conclude with an outlook on the future of biosensor development, in which we discuss adaptability to emerging contaminants, outline current limitations, and propose steps to overcome the field's outstanding challenges to facilitate global water quality monitoring.

12.
J Mech Behav Biomed Mater ; 111: 103991, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32823075

RESUMO

Chitons are herbivorous invertebrates that use rows of ultrahard magnetite-based teeth connected to a flexible belt (radula) to rasp away algal deposits growing on and within rocky outcrops along coastlines around the world. Each tooth is attached to the radula by an organic structure (stylus) that provides mechanical support during feeding. However, the underlying structures within the stylus, and their subsequent function within the chiton have yet to be investigated. Here, we investigate the macrostructural architecture, the regional material and elemental distribution and subsequent nano-mechanical properties of the stylus from the Northern Pacific dwelling Cryptochiton stelleri. Using a combination of µ-CT imaging, optical and electron microscopy, as well as elemental analysis, we reveal that the stylus is a highly contoured tube, mainly composed of alpha-chitin fibers, with a complex density distribution. Nanoindentation reveals regiospecific and graded mechanical properties that can be correlated with both the elemental composition and material distribution. Finite element modeling shows that the unique macroscale architecture, material distribution and elemental gradients have been optimized to preserve the structural stability of this flexible, yet robust functionally-graded fiber-reinforced composite tube, providing effective function during rasping. Understanding these complex fiber-based structures offers promising blueprints for lightweight, multifunctional and integrated materials.


Assuntos
Poliplacóforos , Dente , Animais , Óxido Ferroso-Férrico , Microscopia Eletrônica
13.
Nat Biotechnol ; 38(12): 1451-1459, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32632301

RESUMO

Lack of access to safe drinking water is a global problem, and methods to reliably and easily detect contaminants could be transformative. We report the development of a cell-free in vitro transcription system that uses RNA Output Sensors Activated by Ligand Induction (ROSALIND) to detect contaminants in water. A combination of highly processive RNA polymerases, allosteric protein transcription factors and synthetic DNA transcription templates regulates the synthesis of a fluorescence-activating RNA aptamer. The presence of a target contaminant induces the transcription of the aptamer, and a fluorescent signal is produced. We apply ROSALIND to detect a range of water contaminants, including antibiotics, small molecules and metals. We also show that adding RNA circuitry can invert responses, reduce crosstalk and improve sensitivity without protein engineering. The ROSALIND system can be freeze-dried for easy storage and distribution, and we apply it in the field to test municipal water supplies, demonstrating its potential use for monitoring water quality.


Assuntos
Técnicas Biossensoriais/métodos , Poluentes Químicos da Água/análise , Aptâmeros de Nucleotídeos/metabolismo , Fluorescência , Liofilização , Genes Reporter , Ligantes , Metais/metabolismo , RNA/metabolismo , Bibliotecas de Moléculas Pequenas/química , Fatores de Transcrição/metabolismo , Transcrição Gênica
14.
J Mater Sci Mater Med ; 20(12): 2441-53, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19593649

RESUMO

The primary goal of this investigation was to develop a calcium phosphate film hybridized with 1alpha,25-dihydroxyvitamin D(3) for the improvement of osteoconductivity of bone substitutes. The hybrid films (hCaP) were prepared at the different concentrations of 1 x 10(-10), 1 x 10(-8), and 1 x 10(-6) M designated as hCaPL, hCaPM, and hCaPH, respectively. The change of the hormone concentration during the preparation of the hybrid films did not cause significant variations on the physical properties of hCaPs, i.e. surface morphology and roughness. On the other hand, X-ray photon spectroscope (XPS) measurements revealed that the concentration change affected the chemical composition of the hybrid films. Recruitment of osteoblast-like MG-63 cells was considerably improved on hCaPs compared to tissue culture plate (TCP). However, cell proliferation on hCaPs was substantially suppressed and inversely proportional to the hormone concentration used. It was observed that bone-like nodules which consisted of bead-like components and well-developed matrix were rapidly formed on hCaPs. Masson's trichrome and safranin-O stainings elucidated that the bead-like components were MG-63 cells. Safranin-O staining showed that proteoglycan was produced actively. These results indicate that the cells cultured on hCaPs were strongly stimulated by the hormone to produce proteoglycan which can be considered as an induction of premature bone formation. The number of the nodules was increased with hormone concentration and most pronounced at the hCaPH. Gene expression patterns of alkaline phosphatase (ALP), transforming growth factor-beta (TGF-beta), and osteopontin (OPN) were strongly modulated by hybridized the hormone. For ALP and OPN, gene expressions were activated earlier on hCaPs than untreated calcium phosphate (CaP) confirming the effect of the hybridization was substantial. The TGF-beta gene expression was immediately activated after seeding but difference between samples was not significant suggesting that the gene expression was modulated not by the hormone hybridization but by CaP itself. As a result, hybridization of 1,25(OH)(2)D(3) with CaP can be a potentially strong candidate to promote osteoconductivity of implant materials.


Assuntos
Calcitriol/química , Fosfatos de Cálcio/química , Sequência de Bases , Adesão Celular , Linhagem Celular Tumoral , Proliferação de Células , Primers do DNA , Regulação da Expressão Gênica , Humanos , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise Espectral/métodos
15.
ACS Biomater Sci Eng ; 5(5): 2122-2133, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-33405715

RESUMO

As with most biological materials, natural bone has hierarchical structure. The microstructural features of compact bone are of various length scales with its porosity consisting of larger osteons (∼100 µm diameter) and vascular channels, as well as smaller lacuna spaces (∼10 µm diameter). In this study, the freeze-casting process, which has been previously used to form biocompatible porous scaffolds (made with hydroxyapatite, HA) has been improved to mimic the intrinsic hierarchical structure of natural bone by implementing an extrinsic 3D printed template. The results of pore characterization showed that this novel combined method of 3D printing and freeze-casting is able to produce porosity at multiple length scales. Nonporous, microporous (created with freeze-casting alone), and macro-micro porous (created with freeze-casting and 3D printed templating) scaffolds were compared as substrates to evaluate cellular activities using osteoblast-like MG63 cell lines. The number of cells oriented parallel to the HA wall structures in the freeze-cast scaffold was found to increase on the microporous and macro-micro porous samples when compare to the nonporous samples, mimicking the natural alignment of the lamella of natural bone. Regarding the cell morphologies, cells on microporous and macro-micro porous samples showed narrowly aligned shapes, whereas those on nonporous samples had polygonal shapes with no discernible orientation. Proliferation and differentiation tests demonstrated that no toxicity or functional abnormalities were found in any of the substrates due to potential chemical and mechanical residues that may have been introduced by the freeze-casting process. Monitoring of the three-dimensional distribution of cells in the scaffolds through microcomputed tomography indicates that the cells were well distributed in the interior pore spaces via the interpenetrating macro-micro pore networks. In summary, we demonstrate this novel approach can create porosity at multiple length scales and is highly favorable in creating a biocompatible, osteoconductive, and structurally hierarchical HA scaffolds for biomedical applications.

16.
Adv Mater ; 31(43): e1901561, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31268207

RESUMO

Biological materials found in Nature such as nacre and bone are well recognized as light-weight, strong, and tough structural materials. The remarkable toughness and damage tolerance of such biological materials are conferred through hierarchical assembly of their multiscale (i.e., atomic- to macroscale) architectures and components. Herein, the toughening mechanisms of different organisms at multilength scales are identified and summarized: macromolecular deformation, chemical bond breakage, and biomineral crystal imperfections at the atomic scale; biopolymer fibril reconfiguration/deformation and biomineral nanoparticle/nanoplatelet/nanorod translation, and crack reorientation at the nanoscale; crack deflection and twisting by characteristic features such as tubules and lamellae at the microscale; and structure and morphology optimization at the macroscale. In addition, the actual loading conditions of the natural organisms are different, leading to energy dissipation occurring at different time scales. These toughening mechanisms are further illustrated by comparing the experimental results with computational modeling. Modeling methods at different length and time scales are reviewed. Examples of biomimetic designs that realize the multiscale toughening mechanisms in engineering materials are introduced. Indeed, there is still plenty of room mimicking the strong and tough biological designs at the multilength and time scale in Nature.


Assuntos
Materiais Biomiméticos , Fenômenos Mecânicos , Animais , Materiais Biomiméticos/química , Biopolímeros/química , Humanos
17.
Trials ; 20(1): 216, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30987662

RESUMO

BACKGROUND: Low back pain (LBP) is common, with a lifetime prevalence of 80%, and as such it places substantial social and economic burden on individuals and society. Chuna manual therapy (CMT) combines aspects of physiology, biodynamics of spine and joint motion, and basic theory of movement dynamics. This study aimed to test the comparative effectiveness and safety of CMT for non-acute LBP. METHODS: A three-arm, multicenter, pragmatic, randomized controlled pilot trial was conducted from 28 March 2016 to 19 September 2016, at four medical institutions. A total of 60 patients were randomly allocated to the CMT group (n = 20), usual care (UC) group (n = 20), or combined treatment (CMT + UC) group (n = 20), and received the relevant treatments for 6 weeks. The primary outcome was a numeric rating scale (NRS) representation of LBP intensity, while secondary outcomes included NRS of leg pain, Oswestry disability index (ODI), Patient Global Impression of Change (PGIC), the EuroQol-5 dimensions (EQ-5D), lumbar range of motion, and safety. RESULTS: A total of 60 patients were included in the intention-to-treat analysis and 55 patients (CMT, 18; UC, 18; CMT + UC, 19) were included in the per-protocol analysis (drop-out rate 5.3%). Over the treatment period there were significant differences in the NRS score for LBP (CMT mean - 3.28 (95% CI - 4.08, - 2.47); UC - 1.95 (- 2.82, - 1.08); CMT + UC - 1.75 (- 2.70, - 0.80), P < 0.01) and the ODI scores in each group (CMT - 12.29 (- 16.86, - 7.72); UC - 10.34 (- 14.63, - 6.06); CMT + UC - 9.27 (- 14.28, - 4.26), P < 0.01). The changes in other secondary outcomes did not significantly differ among the three groups. Sixteen minor-to-moderate safety concerns were reported. CONCLUSIONS: Our results suggest that CMT has comparative efficacy for non-acute LBP and is generally safe. As this was a preliminary study, a well-powered (over 192 participants) two-arm (CMT versus UC) verification trial will be performed to assess the generalizability of these results. TRIAL REGISTRATION: Clinical Research Information Service (CRIS), KCT0001850 . Registered on 12 March 2016.


Assuntos
Dor Lombar/terapia , Manipulações Musculoesqueléticas/métodos , Adulto , Pesquisa Comparativa da Efetividade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Manipulações Musculoesqueléticas/efeitos adversos , Projetos Piloto , Amplitude de Movimento Articular
18.
Exp Neurobiol ; 28(2): 183-215, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31138989

RESUMO

In the brain, a reduction in extracellular osmolality causes water-influx and swelling, which subsequently triggers Cl-- and osmolytes-efflux via volume-regulated anion channel (VRAC). Although LRRC8 family has been recently proposed as the pore-forming VRAC which is activated by low cytoplasmic ionic strength but not by swelling, the molecular identity of the pore-forming swelling-dependent VRAC (VRACswell) remains unclear. Here we identify and characterize Tweety-homologs (TTYH1, TTYH2, TTYH3) as the major VRACswell in astrocytes. Gene-silencing of all Ttyh1/2/3 eliminated hypo-osmotic-solution-induced Cl- conductance (ICl,swell) in cultured and hippocampal astrocytes. When heterologously expressed in HEK293T or CHO-K1 cells, each TTYH isoform showed a significant ICl,swell with similar aquaporin-4 dependency, pharmacological properties and glutamate permeability as ICl,swell observed in native astrocytes. Mutagenesis-based structure-activity analysis revealed that positively charged arginine residue at 165 in TTYH1 and 164 in TTYH2 is critical for the formation of the channel-pore. Our results demonstrate that TTYH family confers the bona fide VRACswell in the brain.

19.
J Mech Behav Biomed Mater ; 84: 273-280, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29852315

RESUMO

Woodpeckers peck at trees without any reported brain injury despite undergoing high impact loads. Amongst the adaptations allowing this is a highly functionalized impact-absorption system consisting of the head, beak, tongue and hyoid bone. This study aims to examine the anatomical structure, composition, and mechanical properties of the skull to determine its potential role in energy absorption and dissipation. An acorn woodpecker and a domestic chicken are compared through micro-computed tomography to analyze and compare two- and three-dimensional bone morphometry. Optical and scanning electron microscopy with energy dispersive X-ray spectroscopy are used to identify the structural and chemical components. Nanoindentation reveals mechanical properties along the transverse cross-section, normal to the direction of impact. Results show two different strategies: the skull bone of the woodpecker shows a relatively small but uniform level of closed porosity, a higher degree of mineralization, and a higher cortical to skull bone ratio. Conversely, the chicken skull bone shows a wide range of both open and closed porosity (volume fraction), a lower degree of mineralization, and a lower cortical to skull bone ratio. This structural difference affects the mechanical properties: the skull bones of woodpeckers are slightly stiffer than those of chickens. Furthermore, the Young's modulus of the woodpecker frontal bone is significantly higher than that of the parietal bone. These new findings may be useful to potential engineered design applications, as well as future work to understand how woodpeckers avoid brain injury.


Assuntos
Galinhas , Fenômenos Mecânicos , Crânio , Animais , Fenômenos Biomecânicos , Teste de Materiais , Nanotecnologia , Crânio/química , Crânio/diagnóstico por imagem , Microtomografia por Raio-X
20.
J Ethnopharmacol ; 225: 198-201, 2018 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-30009978

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Dangguisusan (DGSS) is a widely used prescription for the treatment of traumatic injury in Korean medicine. AIM OF THE STUDY: To demonstrate the effects of DGSS on a mouse model of traumatic brain injury (TBI) for providing scientific evidence in clinical use. MATERIALS AND METHODS: TBI was induced in a mouse model using the controlled cortical impact method. Water extract of DGSS (50, 150, and 450 mg/kg) was administered twice a day for 8 d. Histological analyses were performed 8 d after TBI. Moreover, beam-walking, grip-strength, and novel object recognition (NOR) tests were conducted to evaluate the effects on motor function, muscle strength, and cognitive memory function, respectively. RESULT: DGSS inhibited body weight loss, hippocampal damage, and neuronal loss in the thalamic region. Furthermore, it reduced transverse time and foot faults in the beam-walking test at 3 d and increased the muscle strength in the grip-strength test at 3 and 8 d. It also improved the recognition index (%) in the NOR test. However, DGSS did not show protective effects against total damage. CONCLUSIONS: DGSS might improve sensory-motor and cognitive functions after TBI with partial protective effects against brain damage. The present findings provide a scientific basis for the clinical use of DGSS in TBI.


Assuntos
Lesões Encefálicas Traumáticas/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Extratos Vegetais/uso terapêutico , Animais , Comportamento Animal/efeitos dos fármacos , Modelos Animais de Doenças , Hipocampo/efeitos dos fármacos , Masculino , Camundongos Endogâmicos ICR , Neurônios/efeitos dos fármacos
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