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American Journal of Orthodontics and... Aug 2007We have successfully treated skeletal open bite by intruding posterior teeth with the skeletal anchorage system. Our aim in this study was to morphologically and...
INTRODUCTION
We have successfully treated skeletal open bite by intruding posterior teeth with the skeletal anchorage system. Our aim in this study was to morphologically and hemodynamically evaluate the changes in pulp tissues when molars are radically intruded.
METHODS
The mandibular fourth premolars of 9 adult beagle dogs were divided into 3 groups: a sham operated group (n = 6, 3 dogs), 4-month intrusion group (n = 6, 3 dogs), and a further 4-month retention group (n = 6, 3 dogs). We evaluated the morphological changes of the pulp and dentin-the amount of vacuolar degeneration in the odontoblast layer, the predentin width and nervous continuity in the pulp tissue, and the pulpal blood-flow response evoked by electrical stimulation in the dental pulp.
RESULTS
Extreme molar intrusion with the skeletal anchorage system caused slight degenerative changes in the pulp tissue, followed by recovery after the orthodontic force was released. Circulatory system and nervous functions were basically maintained during the intrusion, although a certain level of downregulation was observed. These morphologic and functional regressive changes in the pulp tissue after molar intrusion improved during the retention period.
CONCLUSIONS
Histologic changes and changes in pulpal blood flow and function are reversible, even during radical intrusion of molars.
Topics: Animals; Dental Pulp; Dogs; Electric Stimulation; Female; Laser-Doppler Flowmetry; Molar; Open Bite; Orthodontic Anchorage Procedures; Pilot Projects; Radiography; Reproducibility of Results; Tooth Movement Techniques
PubMed: 17693370
DOI: 10.1016/j.ajodo.2005.07.029 -
ACS Omega Feb 2017A microporous pH- and light-responsive membrane that enables remote control over its interfacial properties has been fabricated. pH-Responsiveness was imparted to a...
A microporous pH- and light-responsive membrane that enables remote control over its interfacial properties has been fabricated. pH-Responsiveness was imparted to a porous polypropylene film via grafting of poly(methacrylic acid) brushes from the substrate using argon-plasma-induced free-radical graft polymerization. Morphological changes as a function of grafting level were analyzed using atomic force microscopy. Conversion into a light-responsive membrane was performed via postpolymerization modification to covalently attach photochromic spiropyran moieties to the grafted polymer brushes. Reversible switches in wettability and permeability were determined upon changing from acidic to basic pH or upon alternating UV- and visible-light irradiation. Additionally, light-responsive membranes show a switch in color upon UV exposure.
PubMed: 31457450
DOI: 10.1021/acsomega.6b00394 -
Journal of Biomedical Materials Research Sep 1995The clinical success of any implant is directly dependent upon the cellular behavior in the immediate vicinity of the interface established between the host tissue and...
The clinical success of any implant is directly dependent upon the cellular behavior in the immediate vicinity of the interface established between the host tissue and the biomaterial(s) used to fabricate the device. All biomaterials have morphologic, chemical, and electrical surface characteristics that influence the cellular response to the implant. Quantitative measurement of specific aspects of this local host response to different but well-characterized biomaterial surfaces provides a crucial link in the understanding of the overall phenomenon of implant biocompatibility. A system has been devised for in vitro examination of responses of cells to controlled but independent changes in both the chemistry and morphology of polystyrene (PS) tissue culture surfaces. Micromachined silicon wafers were used as templates to solvent-cast PS replicas [using 0, 1, or 2 wt % styrene (S) monomer additions] with either none, 0.5- or 5.0-microns-deep surface grooves arranged in a radial array. When all possible morphologies were combined with all possible polymers, nine model biomaterial surfaces (MBSs) were produced. The chemical characteristics of the MBSs were determined using electron spectroscopy for chemical analysis, secondary ion mass spectroscopy, and contact angle techniques and were found to be distinct. The types and amount of proteins that adsorb onto these surfaces from serum containing media were examined and found to consist of multiple molecular layers of relatively uniform composition. Self-contained tissue culture vessels formed from the MBSs were capable of supporting the growth of confluent cultures of rat calvarial cells. The model biomaterial system described here can be used to examine how simultaneous stimuli resulting from the chemical and morphological characteristics of a test material may influence biologic responses. Such multifactorial biocompatibility research is needed to properly document material-host interactions.
Topics: Absorption; Animals; Animals, Newborn; Biocompatible Materials; Blood Proteins; Cattle; Cell Survival; Cells, Cultured; Culture Media; Electron Probe Microanalysis; Electrophoresis, Polyacrylamide Gel; Polystyrenes; Rats; Rats, Sprague-Dawley; Skull; Spectrometry, Mass, Secondary Ion; Surface Properties
PubMed: 8567707
DOI: 10.1002/jbm.820290909 -
Journal of Biomedical Materials... Jan 2021Like many other cell types, neuroblastoma cells are also known to respond to mechanical cues in their microenvironment in vitro. They were shown to have...
Like many other cell types, neuroblastoma cells are also known to respond to mechanical cues in their microenvironment in vitro. They were shown to have mechanotransduction pathways, which result in enhanced neuronal morphology on stiff substrates. However, in previous studies, the differentiation process was monitored only by morphological parameters. Motivated by the lack of comprehensive studies that investigate the effects of mechanical cues on neuroblastoma differentiation, we used SH-SY5Y cells differentiated on polyacrylamide (PA) gels as a model. Cells differentiated on the surface of PA hydrogels with three different elastic moduli (0.1, 1, and 50 kPa) were morphologically evaluated and their electrophysiological responsiveness was probed using calcium imaging. Immunodetection of neural marker TUJ1 and p-FAK was used for biochemical characterization. Groups with defined stiffness that are matching and nonmatching to neural tissue extracellular matrix were used to distinguish biomimetic results from other effects. Results show that while cells display morphologies that do not resemble neurons on soft substrates, they are in fact electrophysiologically more responsive and abundant in neuronal marker TUJ1. Our findings suggest that while neuronal differentiation occurs more efficiently in microenvironments mechanically mimicking neural tissue, the SH-SY5Y model demonstrates morphologies that conflict with neuronal behavior under these conditions. These results are expected to contribute considerable input to researchers that use SH-SY5Y as a neuron model.
Topics: Acrylic Resins; Biomarkers; Cell Differentiation; Focal Adhesion Kinase 1; Humans; Hydrogels; Mechanical Phenomena; Mechanotransduction, Cellular; Neuroblastoma; Neurons; Surface Properties; Tubulin
PubMed: 32627383
DOI: 10.1002/jbm.b.34684 -
Frontiers in Zoology 2014Sexually selected traits contribute substantially to evolutionary diversification, for example by promoting assortative mating. The contributing traits and their...
INTRODUCTION
Sexually selected traits contribute substantially to evolutionary diversification, for example by promoting assortative mating. The contributing traits and their relevance for reproductive isolation differ between species. In birds, sexually selected acoustic and visual signals often undergo geographic divergence. Clines in these phenotypes may be used by both sexes in the context of sexual selection and territoriality. The ways conspecifics respond to geographic variation in phenotypes can give insights to possible behavioural barriers, but these may depend on migratory behaviour. We studied a migratory songbird, the Stonechat, and tested its responsiveness to geographic variation in male song and morphology. The traits are acquired differently, with possible implications for population divergence. Song can evolve quickly through cultural transmission, and thus may contribute more to the establishment of geographic variation than inherited morphological traits. We first quantified the diversity of song traits from different populations. We then tested the responses of free-living Stonechats of both sexes to male phenotype with playbacks and decoys, representing local and foreign stimuli derived from a range of distances from the local population.
RESULTS
Both sexes discriminated consistently between stimuli from different populations, responding more strongly to acoustic and morphological traits of local than foreign stimuli. Time to approach increased, and time spent close to the stimuli and number of tail flips decreased consistently with geographic distance of the stimulus from the local population. Discriminatory response behaviour was more consistent for acoustic than for morphological traits. Song traits of the local population differed significantly from those of other populations.
CONCLUSIONS
Evaluating an individual's perception of geographic variation in sexually selected traits is a crucial first step for understanding reproductive isolation mechanisms. We have demonstrated that in both sexes of Stonechats the responsiveness to acoustic and visual signals decreased with increasing geographic distance of stimulus origin. These findings confirm consistent, fine discrimination for both learned song and inherited morphological traits in these migratory birds. Maintenance or further divergence in phenotypic traits could lead to assortative mating, reproductive isolation, and potentially speciation.
PubMed: 25484906
DOI: 10.1186/s12983-014-0085-6 -
Toxicologic Pathology Aug 2011The heart is increasingly recognized as a target for toxicity. As studies in laboratory rodents are commonly used to investigate the potential toxicity of various...
The heart is increasingly recognized as a target for toxicity. As studies in laboratory rodents are commonly used to investigate the potential toxicity of various agents, the identification and characterization of lesions of cardiotoxicity is of utmost importance. Although morphologic criteria have been established for degenerative myocardial lesions in rats and mice, differentiation of spontaneously occurring lesions from toxin-induced or toxin-related lesions remains difficult. A retrospective light microscopic evaluation was performed on the hearts of F344 rats and B6C3F(1) mice from National Toxicology Program (NTP) studies of six chemicals identified in the NTP database in which treatment-induced myocardial toxicity was present. Two previously defined myocardial lesions were observed: "cardiomyopathy" that occurred spontaneously or as a treatment-related effect and "myocardial degeneration" that occurred as a treatment-related effect. Both lesions consisted of the same basic elements, beginning with myofiber degeneration and necrosis, with varying amounts of inflammation, interstitial cell proliferation, and eventual fibrosis. This observation is indicative of the heart's limited repertoire of responses to myocardial injury, regardless of the nature of the inciting agent. A prominent differentiating factor between spontaneous and treatment-induced lesions was distribution and lesion onset. Once the respective lesions had undergone fibrosis, however, they generally appeared morphologically indistinguishable.
Topics: Animals; Biomedical Research; Cardiomyopathies; Cardiotoxins; Government Programs; Heart; Histocytochemistry; Mice; Microscopy; Myocardium; Myocytes, Cardiac; Oxymetholone; Rats; Rats, Inbred F344; Retrospective Studies; Toxicity Tests; United States; United States Dept. of Health and Human Services; Urethane; Vacuoles
PubMed: 21747121
DOI: 10.1177/0192623311413788 -
Molecular Cell Oct 2019The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development. The auxin response factor (ARF) transcription factor family regulates...
The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development. The auxin response factor (ARF) transcription factor family regulates auxin-responsive gene expression and exhibits nuclear localization in regions of high auxin responsiveness. Here we show that the ARF7 and ARF19 proteins accumulate in micron-sized assemblies within the cytoplasm of tissues with attenuated auxin responsiveness. We found that the intrinsically disordered middle region and the folded PB1 interaction domain of ARFs drive protein assembly formation. Mutation of a single lysine within the PB1 domain abrogates cytoplasmic assemblies, promotes ARF nuclear localization, and results in an altered transcriptome and morphological defects. Our data suggest a model in which ARF nucleo-cytoplasmic partitioning regulates auxin responsiveness, providing a mechanism for cellular competence for auxin signaling.
Topics: Arabidopsis; Arabidopsis Proteins; Cell Nucleus; Cytoplasm; Gene Expression Regulation, Plant; Indoleacetic Acids; Intrinsically Disordered Proteins; Plant Growth Regulators; Protein Binding; Protein Folding; Protein Interaction Domains and Motifs; Structure-Activity Relationship; Transcription Factors
PubMed: 31421981
DOI: 10.1016/j.molcel.2019.06.044 -
Journal of Experimental Botany Aug 2022Soil mechanical impedance precludes root penetration, confining root system development to shallow soil horizons where mobile nutrients are scarce. Using a...
Soil mechanical impedance precludes root penetration, confining root system development to shallow soil horizons where mobile nutrients are scarce. Using a two-phase-agar system, we characterized Arabidopsis responses to low and high mechanical impedance at three root penetration stages. We found that seedlings whose roots fail to penetrate agar barriers show a significant reduction in leaf area, root length, and elongation zone and an increment in root diameter, while those capable of penetrating show only minor morphological effects. Analyses using different auxin-responsive reporter lines, exogenous auxins, and inhibitor treatments suggest that auxin responsiveness and PIN-mediated auxin distribution play an important role in regulating root responses to mechanical impedance. The assessment of 21 Arabidopsis accessions revealed that primary root penetrability varies widely among accessions. To search for quantitative trait loci (QTLs) associated to root system penetrability, we evaluated a recombinant inbred population derived from Landsberg erecta (Ler-0, with a high primary root penetrability) and Shahdara (Sha, with a low primary root penetrability) accessions. QTL analysis revealed a major-effect QTL localized in chromosome 3, ROOT PENETRATION INDEX 3 (q-RPI3), which accounted for 29.98% (logarithm of odds=8.82) of the total phenotypic variation. Employing an introgression line (IL-321) with a homozygous q-RPI3 region from Sha in the Ler-0 genetic background, we demonstrated that q-RPI3 plays a crucial role in root penetrability. This multiscale study reveals new insights into root plasticity during the penetration process in hard agar layers, natural variation, and genetic architecture behind primary root penetrability in Arabidopsis.
Topics: Agar; Arabidopsis; Indoleacetic Acids; Quantitative Trait Loci; Soil
PubMed: 35512438
DOI: 10.1093/jxb/erac188 -
IEEE Transactions on Nanobioscience Dec 2017Self-assembled nanoformulations have been finding various applications in biomedical sciences. Here, we have designed and synthesized a small molecule-based amphiphilic...
Self-assembled nanoformulations have been finding various applications in biomedical sciences. Here, we have designed and synthesized a small molecule-based amphiphilic conjugate of azobenzene, Azo-PEG-OMe, which self-assembles into nanostructures in an aqueous environment. The formation of nanostructures was evidenced by light scattering and electron microscopic analyses, which revealed the size of the so formed nanostructures ~199 and ~42 nm, respectively. Responsiveness of these nanostructures to various stimuli was demonstrated by enzyme and UV-Vis light exposure, pH and chemical reductant, sodium dithionite. Morphological alterations in the nanostructures on exposure to these stimuli were recorded and subsequently, these nanostructures were demonstrated as efficient carrier of drugs by entrapping an antiprotozoan drug, ornidazole, with ~82% entrapment efficiency. Under influence of different stimuli (light, pH, and enzyme), the drug release behavior displayed good response to each stimulus implying that the projected nanostructures could be used as efficient drug delivery system. Response to azoreductase enzyme further established that the formulation can be used for site specific drug delivery particularly useful for colonic drug delivery.
Topics: Azo Compounds; Colonic Neoplasms; Drug Carriers; Humans; MCF-7 Cells; Nanostructures; Ornidazole; Particle Size; Polyethylene Glycols
PubMed: 28976319
DOI: 10.1109/TNB.2017.2757958 -
Materials & Design Jun 2023After the pandemic of SARS-CoV-2, the use of face-masks is considered the most effective way to prevent the spread of virus-containing respiratory fluid. As the virus...
After the pandemic of SARS-CoV-2, the use of face-masks is considered the most effective way to prevent the spread of virus-containing respiratory fluid. As the virus targets the lungs directly, causing shortness of breath, continuous respiratory monitoring is crucial for evaluating health status. Therefore, the need for a smart face mask (SFM) capable of wirelessly monitoring human respiration in real-time has gained enormous attention. However, some challenges in developing these devices should be solved to make practical use of them possible. One key issue is to design a wearable SFM that is biocompatible and has fast responsivity for non-invasive and real-time tracking of respiration signals. Herein, we present a cost-effective and straightforward solution to produce innovative SFMs by depositing graphene-based coatings over commercial surgical masks. In particular, graphene nanoplatelets (GNPs) are integrated into a polycaprolactone (PCL) polymeric matrix. The resulting SFMs are characterized morphologically, and their electrical, electromechanical, and sensing properties are fully assessed. The proposed SFM exhibits remarkable durability (greater than1000 cycles) and excellent fast response time (∼42 ms), providing simultaneously normal and abnormal breath signals with clear differentiation. Finally, a developed mobile application monitors the mask wearer's breathing pattern wirelessly and provides alerts without compromising user-friendliness and comfort.
PubMed: 37162811
DOI: 10.1016/j.matdes.2023.111970