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1.
Neuropathol Appl Neurobiol ; 46(4): 344-358, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31600825

RESUMO

AIMS: Globular glial tauopathy (GGT) is a new category within the 4-repeat tauopathies that is characterised neuropathologically by tau-positive globular glial inclusions (GGIs), namely, globular oligodendrocytic and astrocytic inclusions (GOIs and GAIs). Occurrence of tau-positive neuronal cytoplasmic inclusions (NCIs) is also a feature. GGT is classified into three pathological subtypes (Types I, II and III). We studied the tau pathology in 6 cases of GGT (Type II, n = 3; Type III, n = 3), with special reference to GAIs and NCIs. METHODS: Neuropathological examinations were conducted, along with immunohistochemistry, morphometry and three-dimensional imaging, and biochemical and genetic analysis of tau. RESULTS: The cortical GAIs in Type II and those in Type III were distinguishable from each other. In the motor cortex, GAIs were much more numerous in Type III than in Type II. Prominent occurrence of perikaryal globular structures was a feature of GAIs in Type III. By contrast, prominent occurrence of radiating process-like structures was a feature of GAIs in Type II. Overall, the GAIs were significantly smaller in Type III than in Type II. NCIs were divisible into three subgroups in terms of shape: diffuse granular, thick cord-like, and round/horseshoe-shaped structures. In all cases, NCIs were a feature of the upper and lower motor neurons. Interestingly, the round/horseshoe-shaped NCIs were observed only in Type III cases. CONCLUSIONS: These findings, which characterised GAIs and NCIs, indicated that Type II and Type III constitute two distinct pathological subtypes, and also further strengthen the concept of GGT as a distinct entity.


Assuntos
Encéfalo/patologia , Neuroglia/patologia , Neurônios/patologia , Tauopatias/patologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Corpos de Inclusão/patologia , Masculino
2.
Pharmazie ; 74(1): 62-63, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30782252

RESUMO

Our case was a 70-year-old male (height: 168 cm, weight: 74.3 kg) with polypharmacy (total 15 drugs including 10 tablets) who was treated for HIV infection. His dosing schedule of raltegravir was changed from BID (a 400 mg tablet, twice) to QD (2x600 mg tablet, once). After a month, we found that he miss-took raltegravir for 1x600 mg tablet at once. His HIV-1 RNA increased from undetectable levels to < 20 copies per mL. Pharmaceutical companies should therefore carefully consider swallowing difficulties in old patients, such as by reformulating medications so that only one dosing is required per day and decreasing the size of tablets to 7-8 mm in diameter or orally distinguish tablet.


Assuntos
Fármacos Anti-HIV/administração & dosagem , Infecções por HIV/tratamento farmacológico , RNA Viral/sangue , Raltegravir Potássico/administração & dosagem , Idoso , Transtornos de Deglutição/fisiopatologia , Relação Dose-Resposta a Droga , Esquema de Medicação , Humanos , Masculino , Polimedicação , Comprimidos
3.
Eur J Neurol ; 25(2): 313-319, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29078025

RESUMO

BACKGROUND AND PURPOSE: The present study was conducted to accurately determine the presence of mild cognitive impairment, which is often difficult to evaluate using only simple tests. Our approach focused on discrepancy analysis of fluid intelligence relative to crystallized intelligence using internationally recognized neuropsychological tests. METHODS: One-hundred and five patients diagnosed with asymptomatic carotid artery stenosis were assessed. The neuropsychological tests included the two subtests (information and picture completion) of Wechsler Adult Intelligence Scale-Revised (WAIS-R-two-subtests): crystallized intelligence tests and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) (immediate memory, visuospatial/constructional, language, attention, delayed memory and total score) as fluid intelligence tests. Discrepancy analysis was used to assess cognitive impairment. The score for RBANS was subtracted from the score for WAIS-R-two-subtests, and if the score difference was greater than the 5% confidence limit for statistical significance, it was defined as a decline in cognitive function. RESULTS: The WAIS-R-two-subsets was within normal limits when compared with the standardized values. However, all RBANS domains showed significant declines. Frequencies of decline in each RBANS domain were as follows: 69 patients (66%) in immediate memory, 26 (25%) in visuospatial/constructional, 54 (51%) in language, 63 (60%) in attention, 54 (51%) in delayed memory and 78 (74%) in the total score. Moreover, 99 patients (94%) showed decline in at least one RBANS domain. CONCLUSIONS: Cognitive function is only preserved in a few patients with asymptomatic carotid artery stenosis. Mild cognitive impairment can be precisely detected by performing the discrepancy analysis between crystallized and fluid intelligence tests.


Assuntos
Estenose das Carótidas/complicações , Disfunção Cognitiva/diagnóstico , Interpretação Estatística de Dados , Testes de Inteligência , Testes Neuropsicológicos , Idoso , Idoso de 80 Anos ou mais , Disfunção Cognitiva/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
4.
Andrologia ; 50(7): e13024, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29665107

RESUMO

Klinefelter syndrome is a condition in which a male patient has one Y chromosome and one or more extra X chromosomes. It is the most common sex chromosome disorder. Klinefelter syndrome is distinguished by many clinical features, such as infertility, high gonadotropin and low testosterone levels, increased height, and sparse body and facial hair. We report the case of a 32-year-old man who visited our hospital complaining of male infertility. Semen analysis showed azoospermia, and chromosomal analysis revealed a 47,XY,i(X)(q10) karyotype, which is a rare variant of Klinefelter syndrome. No spermatozoon was found on microdissection testicular sperm extraction, and the testis biopsy histology showed only Sertoli cells and hyalinised seminiferous tubules. 47,XY, i(X)(q10) has an additional isochromosome made of the long arm of the X chromosome, which shares some features of classical Klinefelter syndrome in many aspects, but patients are usually shorter than average height and have normal intelligence. In addition, to the best of our knowledge, no successful sperm extractions from 47,XY, i(X)(q10) patients were reported in the literature. The reports of patients who have undergone microdissection testicular sperm extraction are very rare. Further reports and studies of this chromosomal abnormality are needed.


Assuntos
Azoospermia/genética , Aberrações Cromossômicas , Cromossomos Humanos Y/genética , Síndrome de Klinefelter/genética , Adulto , Azoospermia/diagnóstico , Azoospermia/patologia , Biópsia , Humanos , Cariótipo , Cariotipagem , Síndrome de Klinefelter/diagnóstico , Síndrome de Klinefelter/patologia , Masculino , Testículo/patologia
5.
J Nanobiotechnology ; 14(1): 74, 2016 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-27809857

RESUMO

BACKGROUND: The field of structural dynamics of cytoskeletons in living cells is gathering wide interest, since better understanding of cytoskeleton intracellular organization will provide us with not only insights into basic cell biology but may also enable development of new strategies in regenerative medicine and cancer therapy, fields in which cytoskeleton-dependent dynamics play a pivotal role. The nanoneedle technology is a powerful tool allowing for intracellular investigations, as it can be directly inserted into live cells by penetrating through the plasma membrane causing minimal damage to cells, under the precise manipulation using atomic force microscope. Modifications of the nanoneedles using antibodies have allowed for accurate mechanical detection of various cytoskeletal components, including actin, microtubules and intermediate filaments. However, successful penetration of the nanoneedle through the plasma membrane has been shown to vary greatly between different cell types and conditions. In an effort to overcome this problem and improve the success rate of nanoneedle insertion into the live cells, we have focused here on the fluidity of the membrane lipid bilayer, which may hinder nanoneedle penetration into the cytosolic environment. RESULTS: We aimed to reduce apparent fluidity of the membrane by either increasing the approach velocity or reducing experimental temperatures. Although changes in approach velocity did not have much effect, lowering the temperature was found to greatly improve the detection of unbinding forces, suggesting that alteration in the plasma membrane fluidity led to increase in nanoneedle penetration. CONCLUSIONS: Operation at a lower temperature of 4 °C greatly improved the success rate of nanoneedle insertion to live cells at an optimized approach velocity, while it did not affect the binding of antibodies immobilized on the nanoneedle to vimentins for mechanical detection. As these experimental parameters can be applied to various cell types, these results may improve the versatility of the nanoneedle technology to other cell lines and platforms.


Assuntos
Anticorpos Imobilizados/química , Proteínas do Citoesqueleto/análise , Nanotecnologia/instrumentação , Análise de Célula Única/instrumentação , Anticorpos Imobilizados/metabolismo , Proteínas do Citoesqueleto/química , Proteínas do Citoesqueleto/metabolismo , Células HeLa , Humanos , Células MCF-7 , Microscopia de Força Atômica , Microscopia de Fluorescência , Agulhas , Análise de Célula Única/métodos
6.
Eur Cell Mater ; 30: 187-99, 2015 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-26412389

RESUMO

Odontogenic ameloblast-associated (ODAM) belongs to the secretory calcium-binding phosphoprotein (SCPP) gene cluster. It is expressed by the epithelial ameloblasts during the accrued mineralisation of enamel and by cells of the junctional epithelium (JE), a specialised portion of the gingiva that plays a critical role in periodontal health. In both cases, ODAM localises at the interface between the cells and the tooth surface. It is also present among the cells of the JE, and is distinctively highly expressed in many epithelial tumours. ODAM has been proposed to be a matricellular protein implicated in the adhesion of epithelial cells to tooth surfaces, and possibly in mediating cell status. To gain further understanding of the role of ODAM, we have created an Odam knockout (KO) mouse by deleting coding exons 2-6. Inactivation of the gene was verified by Southern blot, PCR, real-time qPCR and loss of immunostaining for the protein. Young Odam KO mice showed no readily apparent phenotype. No significant differences were observed in enamel volume and density, rod-interrod organisation, and its attrition. However, in older animals, the JE presented some detachment, an increase in inflammatory infiltrate, and apical down-growth. In addition, its regeneration was delayed following a gingivectomy challenge. Our results indicate that inactivation of Odam expression has no dramatic consequence on enamel but the phenotype in older animals replicates some JE changes seen during human periodontal disease. Altogether, our results suggest that ODAM plays a role in maintaining integrity of the JE.


Assuntos
Ameloblastos/citologia , Inserção Epitelial/citologia , Células Epiteliais/citologia , Odontogênese/genética , Regeneração/genética , Cicatrização , Animais , Gengiva/citologia , Camundongos Knockout , Regeneração/fisiologia
7.
Clin Oral Implants Res ; 26(5): 581-5, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25040888

RESUMO

OBJECTIVES: To achieve ideal functional and aesthetic requirements, ridge augmentation is often required before dental implant placement. Bone augmentation (especially vertical), which normally consists of complex and invasive surgeries, still remains challenge. This study seeks to investigate the feasibility of an injectable in situ gel-forming system containing strontium hydroxyapatite (SrHA) and alginate for minimally invasive bone augmentation in a rat calvarial model. MATERIAL AND METHODS: SrHA-alginate solution was prepared by mixing SrHA powder with alginate solution (20 mg/mL) to the final concentration of 0.5% (w/v). Each animal received a 200-µL single subperiosteal injection of either SrHA-alginate solution or alginate solution. The new bone formation was assessed at 0, 4, and 8 weeks histologically and radiologically. RESULTS: The SrHA-alginate solution materials could form solid gel once injected. As such, no sutures were required to close the injection site. Significantly greater amount of new bone formation was observed in the SrHA-alginate group compared with the alginate group both by micro-CT and by histological section. The newly formed bone in the SrHA-alginate group originated both from the underlying original bone and from the elevated periosteum. A 2.3-fold increase of the vertical bone height was observed in the SrHA-alginate group compared with 1.3-fold increase in the alginate group. CONCLUSIONS: Rat calvarial bone augmentation was achieved by a single subperiosteal injection of SrHA-alginate solution without any administration of stem cells or growth factors. The in situ gel-forming material may hold potential therapeutic benefits for local bone augmentation in a minimally invasive manner.


Assuntos
Hidroxiapatitas/farmacologia , Osteogênese/efeitos dos fármacos , Estrôncio/farmacologia , Alginatos/farmacologia , Animais , Materiais Biocompatíveis/farmacologia , Regeneração Óssea/efeitos dos fármacos , Implantação Dentária Endóssea , Estudos de Viabilidade , Géis , Ácido Glucurônico/farmacologia , Ácidos Hexurônicos/farmacologia , Modelos Animais , Ratos , Crânio
8.
Phys Rev Lett ; 112(3): 034802, 2014 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-24484144

RESUMO

A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [P. Raimondi and A. Seryi, Phys. Rev. Lett. 86, 3779 (2001)]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3 GeV electron beam down to below 65 nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider.

10.
J R Soc Interface ; 21(214): 20230439, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38807527

RESUMO

We present a novel approach to traction force microscopy (TFM) for studying the locomotion of 10 cm long walking centipedes on soft substrates. Leveraging the remarkable elasticity and ductility of kudzu starch gels, we use them as a deformable gel substrate, providing resilience against the centipedes' sharp leg tips. By optimizing fiducial marker size and density and fine-tuning imaging conditions, we enhance measurement accuracy. Our TFM investigation reveals traction forces along the centipede's longitudinal axis that effectively counterbalance inertial forces within the 0-10 mN range, providing the first report of non-vanishing inertia forces in TFM studies. Interestingly, we observe waves of forces propagating from the head to the tail of the centipede, corresponding to its locomotion speed. Furthermore, we discover a characteristic cycle of leg clusters engaging with the substrate: forward force (friction) upon leg tip contact, backward force (traction) as the leg pulls the substrate while stationary, and subsequent forward force as the leg tip detaches to reposition itself in the anterior direction. This work opens perspectives for TFM applications in ethology, tribology and robotics.


Assuntos
Artrópodes , Locomoção , Locomoção/fisiologia , Animais , Artrópodes/fisiologia , Microscopia/métodos
11.
Phys Chem Chem Phys ; 15(5): 1518-25, 2013 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-23238425

RESUMO

Solutions of Nafion® with an ion exchange capacity (IEC) of 0.91 meq g(-1), which are on the verge of the formation of SO(3)H nanoclusters, were spin coated on silicon (Si), glassy carbon (GC) and platinum/silicon (Pt/Si) substrates to form films of up to 256 nm thickness. Nanostructure of the films was studied using Doppler broadening of annihilation radiation (DBAR), positron annihilation lifetime (PAL), X-ray photoelectron spectroscopy (XPS), an atomic force microscope (AFM) and contact angle measurements. Contact angles as low as 10 degrees indicate that the surface of dry ultrathin Nafion® films on Si is highly hydrophilic. XPS data of 10 nm thick, ultrathin film on Si show that oxygen concentration is enhanced and the SO(3)H group concentration, in other words, IEC on the surface is much higher than other films. The S parameter measured by DBAR of an ultrathin Nafion® film on Si is much higher than that of the films on the other substrates. We consider that a large number of hydrophilic, reversed micelle like SO(3)H groups are on the surface of the ultrathin Nafion® film on Si but not on the surface of other films. Positrons implanted into the film are trapped by the SO(3)H clusters, annihilating with the electrons of oxygen and exhibit the high S parameter. The SO(3)H concentration on the surface of thin Nafion® films on GC and Pt/Si substrates may not be so high as the threshold for the formation of a large number of SO(3)H clusters. Positrons implanted into the films annihilate mostly with fluorine atoms, resulting in a low S parameter. The film-substrate interaction plays an essential role in nanostructuring of Nafion® thin films, which may also be the case for Nafion® on the catalysts of polymer electrolyte fuel cells.

12.
J Oral Rehabil ; 40(4): 239-46, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23398635

RESUMO

Parafunctional habits, such as prolonged clenching and bruxism, have been associated with dysfunctional overloading in the temporomandibular joint (TMJ). In this study, stress distributions in the TMJ were analysed during prolonged clenching, using three-dimensional finite element (FE) models of the TMJ with and without disc displacement. The aim of this study was to investigate stress distribution of the cartilaginous tissues in the TMJ with and without disc displacement. Finite element models were developed on the basis of magnetic resonance images from two subjects with and without anterior disc displacement. Condylar movements recorded during a 5-min clenching were used as the loading condition for stress analysis. In the asymptomatic model, the highest von Mises stresses were located in the lateral area (4·91 MPa) of the disc surfaces, and after 5-min clenching, the higher stresses were still located at the lateral area (3·65 MPa). In all the cartilaginous tissues, 30-50% of stress reduction occurred during 5-min clenching. In contrast, the von Mises stress in the cartilaginous tissues of the symptomatic model with disc displacement was markedly lower, compared with the asymptomatic model. However, in the condylar cartilage, stress relaxation during clenching was not recognised. Furthermore, relatively high stresses were observed in the retrodiscal tissues throughout clenching. The present results indicate that disc position could be involved in the stress distribution of the TMJ components during prolonged clenching.


Assuntos
Análise de Elementos Finitos , Luxações Articulares/fisiopatologia , Contração Muscular/fisiologia , Disco da Articulação Temporomandibular/fisiopatologia , Transtornos da Articulação Temporomandibular/fisiopatologia , Articulação Temporomandibular/fisiopatologia , Adulto , Algoritmos , Fenômenos Biomecânicos , Cartilagem Articular/patologia , Cartilagem Articular/fisiopatologia , Simulação por Computador , Módulo de Elasticidade , Feminino , Fricção , Humanos , Imageamento Tridimensional/métodos , Luxações Articulares/patologia , Imageamento por Ressonância Magnética , Côndilo Mandibular/patologia , Côndilo Mandibular/fisiopatologia , Músculos da Mastigação/fisiopatologia , Modelos Biológicos , Estresse Mecânico , Osso Temporal/patologia , Osso Temporal/fisiopatologia , Articulação Temporomandibular/patologia , Disco da Articulação Temporomandibular/patologia , Transtornos da Articulação Temporomandibular/patologia , Adulto Jovem
13.
J Periodontal Res ; 47(2): 180-7, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21972924

RESUMO

BACKGROUND AND OBJECTIVE: The tooth root is one of the critical parts to maintain tooth function; however, the molecular mechanisms of root development remain unknown. We aimed to identify specific factors for root morphogenesis using a newly developed experimental system. MATERIAL AND METHODS: Tentative cementoblasts and periodontal ligament cells from mouse mandibular molars were isolated using laser capture microdissection. More than 500 cementoblasts and periodontal ligament cells were separately captured. After RNA extraction and amplification, mRNA expression in isolated cementoblasts was compared with that of periodontal ligament cells by cDNA microarray analysis. Then, putative cementoblast-specific genes were subjected to in situ hybridization analysis to confirm the results in mouse mandible. RESULTS: Approximately 2000 genes were differentially expressed between these tissues. Among those genes, zinc finger helicase (ZFH), also termed chromodomain-helicase-DNA-binding protein 3 (Chd3), was one of the highly expressed transcripts in tentative cementoblasts. In situ hybridization revealed that ZFH/Chd3 was strongly expressed in Hertwig's epithelial root sheath rather than in cementum. Moreover, its expression disappeared when root formation was advanced in the first molar. In contrast, Chd3 was continuously expressed in dental epithelial cells of the cervical loop, in which root extension is never terminated. CONCLUSION: These results suggest that ZFH/Chd3 might play an important role in tooth root development and subsequent cementogenesis.


Assuntos
DNA Helicases/genética , Proteínas de Ligação a DNA/genética , Odontogênese/genética , Raiz Dentária/crescimento & desenvolvimento , Ameloblastos/fisiologia , Animais , Técnicas de Cultura de Células , Montagem e Desmontagem da Cromatina/genética , Cemento Dentário/fisiologia , Órgão do Esmalte/crescimento & desenvolvimento , Células Epiteliais/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento/genética , Incisivo/crescimento & desenvolvimento , Microdissecção e Captura a Laser , Masculino , Mandíbula/citologia , Camundongos , Camundongos Endogâmicos ICR , Dente Molar/crescimento & desenvolvimento , Morfogênese/genética , Hibridização de Ácido Nucleico , Análise de Sequência com Séries de Oligonucleotídeos , Ligamento Periodontal/citologia , Germe de Dente/crescimento & desenvolvimento
14.
Curr Opin Cell Biol ; 11(5): 591-6, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10508646

RESUMO

Reports in the past two years have shown that Cdc42, Rac1, and Rho - belonging to the Rho small GTPase family - participate in the regulation of cadherin-mediated cell-cell adhesion. IQGAP1, an effector of Cdc42 and Rac1, interacts with cadherin and beta-catenin and induces the dissociation of alpha-catenin from the cadherin-catenins complex leading to disruption of cell-cell adhesion: activated Cdc42 and Rac1 counteract the effect of IQGAP1. Thus, Cdc42 and Rac1 appear to regulate cadherin-mediated cell-cell adhesion acting through IQGAP1.


Assuntos
Adesão Celular/fisiologia , Transativadores , Proteínas Ativadoras de ras GTPase , Proteínas rho de Ligação ao GTP/fisiologia , Animais , Caderinas/fisiologia , Proteínas de Transporte/fisiologia , Linhagem Celular , Proteínas do Citoesqueleto/fisiologia , Citoesqueleto/fisiologia , Cães , Humanos , alfa Catenina , beta Catenina , Proteína cdc42 de Ligação ao GTP/fisiologia , Proteínas rac1 de Ligação ao GTP/fisiologia
15.
J Mater Sci Mater Med ; 22(6): 1489-99, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21567286

RESUMO

A sputtering technique followed by a low temperature hydrothermal treatment has been demonstrated to produce a dense-and-bioactive hydroxyapatite thin film coating. The purpose of the present study was to investigate osteoblast and osteoclast responses to the hydroxyapatite coated plates and titanium plates with similar roughness. Rat bone marrow stromal cells were cultured on these plates to induce osteoblasts. The cells showed a significantly enhanced proliferation on the hydroxyapatite surface, accompanied by increase of osteoblastic phenotypes. The co-cultured osteoclasts exhibited the significantly different cell number and morphology between the hydroxyapatite and the titanium surfaces. A series of osteoclast marker genes were more stimulated on the hydroxyapatite and thirty two percent of the hydroxyapatite surface area could be resorbed by osteoclasts. The thin film sputtered hydroxyapatite could provide a favorable surface for both osteoblast and osteoclast formation and their function, indicating its good osteoconductivity and biodegradability.


Assuntos
Materiais Revestidos Biocompatíveis/farmacologia , Durapatita/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/fisiologia , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Materiais Revestidos Biocompatíveis/química , Durapatita/química , Galvanoplastia/métodos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Osteoblastos/fisiologia , Osteoclastos/fisiologia , Ratos , Ratos Wistar , Propriedades de Superfície , Regulação para Cima/efeitos dos fármacos
16.
J Periodontal Res ; 45(6): 709-13, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20572917

RESUMO

BACKGROUND AND OBJECTIVE: It has been suggested that epithelial cell rests of Malassez (ERM) may express enamel matrix proteins and play an important role in periodontal regeneration. Two novel proteins, apin (APIN) and amelotin (AMTN), produced by maturation-stage ameloblasts and junctional epithelium, have recently been identified. The objective of this study was to evaluate whether the ERM express APIN and AMTN under normal conditions and after periodontal challenge. MATERIAL AND METHODS: Gingivectomy and orthodontic tooth movement were carried out on the left side of the maxillae of rats. The control group included the untreated contralateral side of these animals and the maxillae of normal, untreated rats. Animals were sacrificed by intracardiac perfusion on days 3 and 5 after the experimental procedures and maxillary molars were decalcified and processed for paraffin embedding. Immunohistochemistry was used to evaluate the expression of various ameloblast products, including APIN, AMTN, ameloblastin (AMBN) and amelogenin (AMEL). RESULTS: At 3 and 5 days after periodontal challenge, ERM were more evident in the periodontal ligament along the root surface and in the root furcations. Immunodetection of APIN, but not of the other three proteins, was observed in the ERM following the disruption of periodontal integrity. No immunolabeling for APIN, AMTN, AMBN and AMEL was detected in the ERM under normal conditions. CONCLUSION: The expression of APIN at an early time-point following disruption of periodontal integrity suggests that this protein may be part of the cascade of events leading to the activation of ERM during periodontal healing and regeneration.


Assuntos
Proteínas de Transporte/biossíntese , Análise do Estresse Dentário , Células Epiteliais/metabolismo , Ligamento Periodontal/metabolismo , Técnicas de Movimentação Dentária , Ameloblastos/metabolismo , Amiloide , Animais , Proteínas do Esmalte Dentário/biossíntese , Inserção Epitelial/citologia , Inserção Epitelial/lesões , Inserção Epitelial/metabolismo , Proteínas da Matriz Extracelular/biossíntese , Gengivectomia , Técnicas Imunoenzimáticas , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Proteínas de Neoplasias , Ligamento Periodontal/citologia , Ligamento Periodontal/lesões , Ratos , Ratos Wistar , Regeneração
17.
Nat Commun ; 11(1): 4821, 2020 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973165

RESUMO

Materials that possess nontrivial topology and magnetism is known to exhibit exotic quantum phenomena such as the quantum anomalous Hall effect. Here, we fabricate a novel magnetic topological heterostructure Mn4Bi2Te7/Bi2Te3 where multiple magnetic layers are inserted into the topmost quintuple layer of the original topological insulator Bi2Te3. A massive Dirac cone (DC) with a gap of 40-75 meV at 16 K is observed. By tracing the temperature evolution, this gap is shown to gradually decrease with increasing temperature and a blunt transition from a massive to a massless DC occurs around 200-250 K. Structural analysis shows that the samples also contain MnBi2Te4/Bi2Te3. Magnetic measurements show that there are two distinct Mn components in the system that corresponds to the two heterostructures; MnBi2Te4/Bi2Te3 is paramagnetic at 6 K while Mn4Bi2Te7/Bi2Te3 is ferromagnetic with a negative hysteresis (critical temperature  ~20 K). This novel heterostructure is potentially important for future device applications.

18.
Osteoarthritis Cartilage ; 17(11): 1408-15, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19477310

RESUMO

The human masticatory system consists of a mandible which is able to move with respect to the skull at its bilateral temporomandibular joint (TMJ) through contractions of the masticatory muscles. Like other synovial joints, the TMJ is loaded mechanically during function. The articular surface of the mandibular condyle is covered with cartilage that is composed mainly of collagen fibers and proteoglycans. This construction results in a viscoelastic response to loading and enables the cartilage to play an important role as a stress absorber during function. To understand its mechanical functions properly, and to assess its limitations, detailed information about the viscoelastic behavior of the mandibular condylar cartilage is required. The purpose of this paper is to review the fundamental concepts of the biomechanical behavior of the mandibular condylar cartilage. This review consists of four parts. Part 1 is a brief introduction of the structure and function of the mandibular condylar cartilage. In Part 2, the biochemical composition of the mandibular condylar cartilage is summarized. Part 3 explores the biomechanical properties of the mandibular condylar cartilage. Finally, Part 4 relates this behavior to the breakdown mechanism of the mandibular condylar cartilage which is associated with the progression of osteoarthritis in the TMJ.


Assuntos
Ácido Hialurônico/metabolismo , Côndilo Mandibular/patologia , Osteoartrite/fisiopatologia , Disco da Articulação Temporomandibular/patologia , Articulação Temporomandibular/patologia , Envelhecimento/fisiologia , Animais , Fenômenos Biomecânicos/fisiologia , Força Compressiva/fisiologia , Humanos , Côndilo Mandibular/metabolismo
19.
J Cell Biol ; 120(5): 1187-95, 1993 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8436590

RESUMO

Evidence is accumulating that the rho family, a member of the ras p21-related small GTP-binding protein superfamily, regulates cell morphology, cell motility, and smooth muscle contraction through the actomyosin system. The actomyosin system is also known to be essential for cytoplasmic division of cells (cytokinesis). In this study, we examined the action of rho p21, its inhibitory GDP/GTP exchange protein, named rho GDI, its stimulatory GDP/GTP exchange protein, named smg GDS, and botulinum ADP-ribosyltransferase C3, known to selectively ADP-ribosylate rho p21 and to impair its function, in the cytoplasmic division using Xenopus embryos. The sperm-induced cytoplasmic division of Xenopus embryos was not affected by microinjection into the embryos of either smg GDS or the guanosine-5'-(3-O-thio)triphosphate (GTP gamma S)-bound form of rhoA p21, one member of the rho family, but completely inhibited by microinjection of rho GDI or C3. Under these conditions, nuclear division occurred normally but the furrow formation, which was induced by the contractile ring consisting of actomyosin just beneath the plasma membrane, was impaired. Comicroinjection of rho GDI with the GTP gamma S-bound form of rhoA p21 prevented the rho GDI action. Moreover, the sperm-induced cytoplasmic division of Xenopus embryos was inhibited by microinjection into the embryos of the rhoA p21 pre-ADP-ribosylated by C3 which might serve as a dominant negative inhibitor of endogenous rho p21. These results indicate that rho p21 together with its regulatory proteins regulates the cytoplasmic division through the actomyosin system.


Assuntos
ADP Ribose Transferases/metabolismo , Toxinas Botulínicas , Divisão Celular , Fase de Clivagem do Zigoto/fisiologia , Proteínas de Ligação ao GTP/fisiologia , Inibidores de Dissociação do Nucleotídeo Guanina , Xenopus laevis/embriologia , Citoesqueleto de Actina/ultraestrutura , Animais , Fase de Clivagem do Zigoto/ultraestrutura , Proteínas de Ligação ao GTP/química , Microinjeções , Processamento de Proteína Pós-Traducional , Relação Estrutura-Atividade , Proteínas rab3 de Ligação ao GTP , Inibidores da Dissociação do Nucleotídeo Guanina rho-Específico , Proteína rhoA de Ligação ao GTP
20.
J Cell Biol ; 144(3): 403-11, 1999 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-9971736

RESUMO

By the yeast two-hybrid screening of a rat brain cDNA library with the regulatory domain of protein kinase C zeta (PKCzeta) as a bait, we have cloned a gene coding for a novel PKCzeta-interacting protein homologous to the Caenorhabditis elegans UNC-76 protein involved in axonal outgrowth and fasciculation. The protein designated FEZ1 (fasciculation and elongation protein zeta-1) consisting of 393 amino acid residues shows a high Asp/Glu content and contains several regions predicted to form amphipathic helices. Northern blot analysis has revealed that FEZ1 mRNA is abundantly expressed in adult rat brain and throughout the developmental stages of mouse embryo. By the yeast two-hybrid assay with various deletion mutants of PKC, FEZ1 was shown to interact with the NH2-terminal variable region (V1) of PKCzeta and weakly with that of PKCepsilon. In the COS-7 cells coexpressing FEZ1 and PKCzeta, FEZ1 was present mainly in the plasma membrane, associating with PKCzeta and being phosphorylated. These results indicate that FEZ1 is a novel substrate of PKCzeta. When the constitutively active mutant of PKCzeta was used, FEZ1 was found in the cytoplasm of COS-7 cells. Upon treatment of the cells with a PKC inhibitor, staurosporin, FEZ1 was translocated from the cytoplasm to the plasma membrane, suggesting that the cytoplasmic translocation of FEZ1 is directly regulated by the PKCzeta activity. Although expression of FEZ1 alone had no effect on PC12 cells, coexpression of FEZ1 and constitutively active PKCzeta stimulated the neuronal differentiation of PC12 cells. Combined with the recent finding that a human FEZ1 protein is able to complement the function of UNC-76 necessary for normal axonal bundling and elongation within axon bundles in the nematode, these results suggest that FEZ1 plays a crucial role in the axon guidance machinery in mammals by interacting with PKCzeta.


Assuntos
Axônios/fisiologia , Proteínas de Caenorhabditis elegans , Proteínas de Ligação a DNA/metabolismo , Genes Supressores de Tumor , Neuropeptídeos/metabolismo , Proteína Quinase C/metabolismo , Proteínas Supressoras de Tumor , Proteínas Adaptadoras de Transdução de Sinal , Sequência de Aminoácidos , Animais , Sítios de Ligação/genética , Células COS , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Diferenciação Celular , Clonagem Molecular , DNA Complementar/genética , Proteínas de Ligação a DNA/genética , Expressão Gênica , Humanos , Camundongos , Dados de Sequência Molecular , Proteínas do Tecido Nervoso , Neuropeptídeos/genética , Células PC12 , Proteína Quinase C/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Saccharomyces cerevisiae/genética , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
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