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1.
Cancer Sci ; 111(11): 3993-3999, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32897597

RESUMO

Various clinical and experimental findings have revealed the causal relationship between autophagy failure and oncogenesis, and several mechanisms have been suggested to explain this relationship. We recently proposed two additional mechanisms: centrosome number dysregulation and the failure of autophagic cell death. Here, we detail the mechanical relationship between autophagy failure and oncogenesis.


Assuntos
Autofagia , Transformação Celular Neoplásica , Neoplasias/etiologia , Neoplasias/metabolismo , Animais , Biomarcadores , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Centrossomo/metabolismo , Progressão da Doença , Suscetibilidade a Doenças , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias/patologia , Transdução de Sinais
2.
EMBO J ; 35(18): 1991-2007, 2016 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-27511903

RESUMO

Autophagy is a cellular process that degrades subcellular constituents, and is conserved from yeast to mammals. Although autophagy is believed to be essential for living cells, cells lacking Atg5 or Atg7 are healthy, suggesting that a non-canonical degradation pathway exists to compensate for the lack of autophagy. In this study, we show that the budding yeast Saccharomyces cerevisiae, which lacks Atg5, undergoes bulk protein degradation using Golgi-mediated structures to compensate for autophagy when treated with amphotericin B1, a polyene antifungal drug. We named this mechanism Golgi membrane-associated degradation (GOMED) pathway. This process is driven by the disruption of PI(4)P-dependent anterograde trafficking from the Golgi, and it also exists in Atg5-deficient mammalian cells. Biologically, when an Atg5-deficient ß-cell line and Atg7-deficient ß-cells were cultured in glucose-deprived medium, a disruption in the secretion of insulin granules from the Golgi occurred, and GOMED was induced to digest these (pro)insulin granules. In conclusion, GOMED is activated by the disruption of PI(4)P-dependent anterograde trafficking in autophagy-deficient yeast and mammalian cells.


Assuntos
Complexo de Golgi/metabolismo , Membranas Intracelulares/metabolismo , Redes e Vias Metabólicas , Proteólise , Saccharomyces cerevisiae/metabolismo , Anfotericina B/metabolismo , Animais , Antifúngicos/metabolismo , Proteína 5 Relacionada à Autofagia/deficiência , Células Cultivadas , Células Secretoras de Insulina/metabolismo , Camundongos Endogâmicos C57BL , Proinsulina/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae
3.
Int Arch Allergy Immunol ; 178(4): 355-362, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30759444

RESUMO

BACKGROUND: Chronic obstructive pulmonary disease (COPD) and asthma have similar clinical features and are both exacerbated by airway infection. OBJECTIVE: To determine whether garenoxacin mesylate hydrate (GRNX) added to the standard care for bacterial infection-induced acute exacerbation of asthma or COPD in adults has clinical benefits. METHOD: This single-arm clinical trial was conducted from January 2015 to March 2016. Adults with a history of asthma or COPD for more than 12 months were recruited within 48 h of presentation with fever and acute deterioration of asthma or COPD requiring additional intervention. Participants were administered 400 mg GRNX daily for 7 days without additional systemic corticosteroids or other antibiotics. The primary outcome was efficacy of GRNX based on clinical symptoms and blood test results after 7 days of treatment. Secondary outcomes were: (1) comparison of the blood test results, radiograph findings, and bacterial culture surveillance before and after treatment; (2) effectiveness of GRNX after 3 days of administration; (3) analyzation of patient symptoms based on patient diary; and (4) continued effectiveness of GRNX on 14th day after the treatment (visit 3). RESULTS: The study included 44 febrile patients (34 asthma and 10 COPD). Frequently isolated bacteria included Moraxella catarrhalis (n = 6) and Klebsiella pneumoniae (n = 4). On visit 2, 40 patients responded, and no severe adverse events were observed. All secondary outcomes showed favorable results. CONCLUSION: GRNX effectively treated asthma and COPD patients with acute bacterial infection without severe adverse events. Further research with a larger study population is needed.


Assuntos
Antibacterianos/uso terapêutico , Asma/tratamento farmacológico , Infecções Bacterianas/complicações , Fluoroquinolonas/uso terapêutico , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Doença Aguda , Idoso , Bactérias/isolamento & purificação , Infecções Bacterianas/tratamento farmacológico , Feminino , Fluoroquinolonas/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade
5.
Proc Jpn Acad Ser B Phys Biol Sci ; 93(6): 378-385, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28603209

RESUMO

ATG5 and ATG7 are considered to be essential molecules for the induction of autophagy. However, we found that cells lacking ATG5 or ATG7 can still form autophagosomes/autolysosomes and perform autophagic protein degradation when subjected to certain types of stress. Although the lipidation of LC3 is accepted as a good indicator of autophagy, this did not occur during ATG5/ATG7-independent alternative autophagy. Unlike conventional autophagy, autophagosomes appeared to be generated in a Rab9-dependent manner by the fusion of the phagophores with vesicles derived from the trans-Golgi and late endosomes. Therefore, mammalian autophagy can occur via at least two different pathways; the ATG5/ATG7-dependent conventional pathway and an ATG5/ATG7-independent alternative pathway.


Assuntos
Proteína 5 Relacionada à Autofagia/fisiologia , Proteína 7 Relacionada à Autofagia/fisiologia , Autofagia , Animais , Autofagossomos/metabolismo , Proteína 5 Relacionada à Autofagia/deficiência , Proteína 5 Relacionada à Autofagia/genética , Proteína 7 Relacionada à Autofagia/deficiência , Proteína 7 Relacionada à Autofagia/genética , Complexo de Golgi/metabolismo , Humanos , Lisossomos/química , Lisossomos/metabolismo
6.
Nature ; 461(7264): 654-8, 2009 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-19794493

RESUMO

Macroautophagy is a process that leads to the bulk degradation of subcellular constituents by producing autophagosomes/autolysosomes. It is believed that Atg5 (ref. 4) and Atg7 (ref. 5) are essential genes for mammalian macroautophagy. Here we show, however, that mouse cells lacking Atg5 or Atg7 can still form autophagosomes/autolysosomes and perform autophagy-mediated protein degradation when subjected to certain stressors. Although lipidation of the microtubule-associated protein light chain 3 (LC3, also known as Map1lc3a) to form LC3-II is generally considered to be a good indicator of macroautophagy, it did not occur during the Atg5/Atg7-independent alternative process of macroautophagy. We also found that this alternative process of macroautophagy was regulated by several autophagic proteins, including Unc-51-like kinase 1 (Ulk1) and beclin 1. Unlike conventional macroautophagy, autophagosomes seemed to be generated in a Rab9-dependent manner by the fusion of isolation membranes with vesicles derived from the trans-Golgi and late endosomes. In vivo, Atg5-independent alternative macroautophagy was detected in several embryonic tissues. It also had a function in clearing mitochondria during erythroid maturation. These results indicate that mammalian macroautophagy can occur through at least two different pathways: an Atg5/Atg7-dependent conventional pathway and an Atg5/Atg7-independent alternative pathway.


Assuntos
Autofagia/fisiologia , Proteínas Associadas aos Microtúbulos/deficiência , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Autofagia/efeitos dos fármacos , Proteína 5 Relacionada à Autofagia , Proteína 7 Relacionada à Autofagia , Proteína Homóloga à Proteína-1 Relacionada à Autofagia , Proteína Beclina-1 , Etoposídeo/farmacologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Privação de Alimentos , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Fagossomos/efeitos dos fármacos , Fagossomos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo
7.
Jpn Dent Sci Rev ; 60: 190-197, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38974884

RESUMO

Most reports on duplicate dentures are introduction to fabrication methods or clinical case reports. Only a few studies have verified their clinical effectiveness; hence, evidence to construct useful clinical guidelines for duplicate denture use is lacking. This review aimed to comprehensively investigate reports on duplicate dentures to accumulate evidences that will contribute to the formulation of clinical practice guidelines. Duplicate dentures are effectively used for impression making and bite registration when fabricating new dentures, thereby reducing the number of clinic visits and treatment time. Duplicate denture can also be used as temporary or new dentures. Older people in whom various adaptive abilities have declined, may find it difficult to adjust to new dentures and experience stress, even if the shape is appropriate. Duplicate dentures, which reproduces the shape of old dentures that they are used to, have the advantage of being more familiar to older people and less stressful. When manufacturing duplicate dentures, digital methods such as milling and three-dimensional printing are superior to conventional methods regarding working time and cost. A notable advantage of the digital method is that the denture shape can be saved as digital data, and the denture can be easily duplicated if lost.

8.
J Biomed Mater Res B Appl Biomater ; 112(7): e35447, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38997799

RESUMO

With dental implant treatment becoming the gold standard, the need for effective bone augmentation prior to implantation has grown. This study aims to evaluate a bone augmentation strategy integrating three key growth factors: bone morphogenetic protein-2 (BMP-2), insulin-like growth factor 1 (IGF-1), and vascular endothelial growth factor (VEGF). Collagen scaffolds incorporating BMP-2, IGF-1, or VEGF were fabricated and categorized into five groups based on their content: scaffold alone; BMP-2 alone (BMP-2); BMP-2 and IGF-1 (BI); BMP-2, IGF-1, and VEGF (BIV); and BMP-2 and IGF-1 with an earlier release of VEGF (BI + V). The prepared scaffolds were surgically implanted into the calvarias of C57BL/6JJcl mice, and hard tissue formation was assessed after 10 and 28 days through histological, tomographic, and biochemical analyses. The combination of BMP-2 and IGF-1 induced a greater volume of hard tissue augmentation compared with that of BMP-2 alone, regardless of VEGF supplementation, and these groups had increased levels of cartilage compared with others. The volume of hard tissue formation was greatest in the BIV group. In contrast, the BI + V group exhibited a hard tissue volume similar to that of the BI group. While VEGF and CD31 levels were highest in the BIV group at 10 days, there was no correlation at the same time point between hard tissue formation and the quantity of M2 macrophages. In conclusion, the simultaneous release of BMP-2, IGF-1, and VEGF proved to be effective in promoting bone augmentation.


Assuntos
Proteína Morfogenética Óssea 2 , Fator de Crescimento Insulin-Like I , Fator A de Crescimento do Endotélio Vascular , Animais , Proteína Morfogenética Óssea 2/farmacologia , Camundongos , Fator de Crescimento Insulin-Like I/farmacologia , Fator de Crescimento Insulin-Like I/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/farmacologia , Alicerces Teciduais/química , Crânio/metabolismo , Camundongos Endogâmicos C57BL , Masculino
9.
J Oral Sci ; 66(2): 102-106, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38417878

RESUMO

PURPOSE: Alveolar osteitis (dry sockets) is a painful condition characterized by a limited immune response. It is typically caused by the removal of blood clots from extracted tooth sockets, which leads to the fermentation of trapped food remnants by oral bacteria in the cavities, producing high concentrations of short-chain fatty acids (SCFAs). This study examined the effects of SCFAs on immunity and bone metabolism. METHODS: Mouse macrophage Raw264.7 cells were treated with oral bacteria supernatants or SCFA mixtures, and inducible nitric oxide synthase (iNOS) levels were determined by western blot. The same cells were treated with SCFA mixtures in the presence of receptor activator of nuclear factor-kappa B ligand (RANKL), and osteoclast-like cells were counted. MC3T3-E1 cells were treated with SCFA mixtures and stained with alizarin red S. RESULTS: Raw264.7 cells treated with oral bacterial culture supernatants of Porphyromonas gingivalis and Fusobacterium nucleatum inhibited lipopolysaccharide (LPS)-induced iNOS production, likely due to SCFA content. SCFA mixtures mimicking these supernatants inhibited the number of RANKL-induced tartrate-resistant acid phosphatase (TRAP)-positive cells and MC3T3-E1 cell mineralization. CONCLUSION: These data suggest that SCFAs produced by P. gingivalis and F. nucleatum may reduce the inflammatory response and mildly induce mineralization of the alveolar walls. These results may contribute to the understanding of alveolar osteitis.


Assuntos
Alvéolo Seco , Camundongos , Animais , Alvéolo Seco/metabolismo , Osteoclastos , Porphyromonas gingivalis , Fosfatase Ácida Resistente a Tartarato/metabolismo , Ácidos Graxos Voláteis/metabolismo , Ácidos Graxos Voláteis/farmacologia
10.
J Dent Sci ; 18(2): 893-897, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37021231

RESUMO

Three-dimensional (3D) cell culture systems are reported to be more physiologically similar to the in vivo state than 2-dimensional (2D) models, which are extensively employed in periodontal research. Herein, we developed a 3D gingival tissue model with both epithelial and lamina propria layers using human gingival epithelial Ca9-22 cells and primary gingival fibroblasts. The epithelial layer of the developed 3D gingival tissue culture was treated with butyrate, a metabolite of oral bacteria, and the treatment induced the release of damage-associated molecular patterns, such as DNA and Sin3A associated protein 130 kDa (SAP130). Taken together, butyrate exposure to the epithelium of 3D gingival epithelial-connective tissue hybrid systems could induce epithelial cell death and the subsequent release of damage-associated molecular patterns.

11.
Juntendo Iji Zasshi ; 69(1): 42-49, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38854847

RESUMO

Objectives: The role of autophagy in pancreatic ß cells has been reported, but the relationship between autophagy and insulin metabolism is complex and is not fully understood yet. Design: We here analyze the relationship between autophagy and insulin metabolism from a morphological aspect. Methods: We observe the morphological changes of ß cell-specific Atg7-deficient mice and Atg5-deficient MIN6 cells with electron microscopy. Results: We find that Atg7-deficient ß cells exhibit a marked expansion of the endoplasmic reticulum (ER). We also find that the inhibitory state of insulin secretion causes morphological changes in the Golgi, including ministacking and swelling. The same morphological alterations are observed when insulin secretion is suppressed in Atg5-deficient MIN6 cells. Conclusions: The defect of autophagy induces ER expansion, and inhibition of insulin secretion induces Golgi swelling, probably via ER stress and Golgi stress, respectively.

12.
Cells ; 12(24)2023 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-38132137

RESUMO

Autophagy is a cellular mechanism that utilizes lysosomes to degrade its own components and is performed using Atg5 and other molecules originating from the endoplasmic reticulum membrane. On the other hand, we identified an alternative type of autophagy, namely, Golgi membrane-associated degradation (GOMED), which also utilizes lysosomes to degrade its own components, but does not use Atg5 originating from the Golgi membranes. The GOMED pathway involves Ulk1, Wipi3, Rab9, and other molecules, and plays crucial roles in a wide range of biological phenomena, such as the regulation of insulin secretion and neuronal maintenance. We here describe the overview of GOMED, methods to detect autophagy and GOMED, and to distinguish GOMED from autophagy.


Assuntos
Autofagia , Complexo de Golgi , Complexo de Golgi/metabolismo , Autofagia/fisiologia , Lisossomos/metabolismo , Retículo Endoplasmático
13.
Heliyon ; 8(8): e10361, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36060989

RESUMO

Two oval sandwich type magnetic attachments set up in various angulations and spacing, then the pattern of retentive force against horizontal displacement studied. A measuring device and methodology that matches ISO 13017 was used. A pair of magnetic attachments fixed on the same plane at a specific distance on the measuring device and set in various angulations. Retentive force readings of magnetic attachments in various setup positions against the horizontal displacement along the major or minor axis directions were taken. The pattern of decline in retentive force as horizontal displacement increased was different across the various set-ups. It was found that the decrease in retentive forces associated with horizontal displacement can be suppressed when the angle between the major axis and the direction of movement is as small as possible. Formation of a 90° angle between major axes of any pair of magnetic attachments led to nullification of the decline in retentive forces associated with displacement in any direction. Therefore, 90° is the practical, ideal set-up angle between any pair of dental magnetic attachments critical for suppression of the loss in retentive force associated with horizontal gap.

14.
J Am Med Dir Assoc ; 23(4): 638-645.e2, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35219603

RESUMO

OBJECTIVES: Oral bacteria may contribute to postoperative infectious complications including postoperative pneumonia or surgical site infection. The aim of this study was to investigate the impact of preoperative dental care on postoperative outcomes among surgical patients under general anesthesia. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: We analyzed clinical records of major surgical patients at a university hospital between 2016 and 2018. Subjects were categorized into either the preoperative dental care group, those being referred to dentists by their surgeons based on an individual surgeon's judgment for dental care before surgery, or the control group. METHODS: The primary outcome was postoperative infectious complications. Secondary outcomes were postoperative inflammation markers (C-reactive protein and fever), and economic outcomes (postoperative length of hospital stay and medical expenses). As the main analysis, the average treatment effects of the preoperative dental care were obtained from the augmented inverse-probability weighting (AIPW) method with consideration of demographics and perioperative risk factors to estimate causal effect of the intervention from the observational data. Then, stratified analyses by age and surgical sites were conducted with the inverse-probability weighting and linear regression methods, respectively. RESULTS: In the AIPW estimation, compared with the control group, the care group saw a significantly lower rate of postoperative infection (average treatment effect -3.02) and shorter fever duration (-2.79 days). The stratified analysis by age revealed significant positive impact of dental care in all age groups, including the highest treatment effects observed among patients younger than 60. Also, treatment effect was observed in wider surgical sites than previously known. CONCLUSION/IMPLICATIONS: This study indicates a significant impact of preoperative dental care on preventing postoperative infection and inflammation. Along with old age or certain types of surgeries in which advantages of dental referral have been already known, preoperative dental referral could be beneficial for broader types of patients.


Assuntos
Procedimentos Cirúrgicos Eletivos , Cuidados Pré-Operatórios , Humanos , Tempo de Internação , Complicações Pós-Operatórias/prevenção & controle , Período Pós-Operatório , Cuidados Pré-Operatórios/métodos , Encaminhamento e Consulta , Estudos Retrospectivos
15.
Nat Commun ; 13(1): 689, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-35115514

RESUMO

As one of the great survivors of the plant kingdom, barnyard grasses (Echinochloa spp.) are the most noxious and common weeds in paddy ecosystems. Meanwhile, at least two Echinochloa species have been domesticated and cultivated as millets. In order to better understand the genomic forces driving the evolution of Echinochloa species toward weed and crop characteristics, we assemble genomes of three Echinochloa species (allohexaploid E. crus-galli and E. colona, and allotetraploid E. oryzicola) and re-sequence 737 accessions of barnyard grasses and millets from 16 rice-producing countries. Phylogenomic and comparative genomic analyses reveal the complex and reticulate evolution in the speciation of Echinochloa polyploids and provide evidence of constrained disease-related gene copy numbers in Echinochloa. A population-level investigation uncovers deep population differentiation for local adaptation, multiple target-site herbicide resistance mutations of barnyard grasses, and limited domestication of barnyard millets. Our results provide genomic insights into the dual roles of Echinochloa species as weeds and crops as well as essential resources for studying plant polyploidization, adaptation, precision weed control and millet improvements.


Assuntos
Produtos Agrícolas/genética , Echinochloa/genética , Evolução Molecular , Genoma de Planta/genética , Genômica/métodos , Plantas Daninhas/genética , Adaptação Fisiológica/genética , Produtos Agrícolas/classificação , Domesticação , Echinochloa/classificação , Fluxo Gênico , Genes de Plantas/genética , Especiação Genética , Geografia , Resistência a Herbicidas/genética , Filogenia , Plantas Daninhas/classificação , Polimorfismo de Nucleotídeo Único , Especificidade da Espécie
16.
Ann Bot ; 108(2): 367-80, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21725064

RESUMO

BACKGROUND AND AIMS: The subgenus Ceratotropis in the genus Vigna is widely distributed from the Himalayan highlands to South, Southeast and East Asia. However, the interspecific and geographical relationships of its members are poorly understood. This study investigates the phylogeny and biogeography of the subgenus Ceratotropis using chloroplast DNA sequence data. METHODS: Sequence data from four intergenic spacer regions (petA-psbJ, psbD-trnT, trnT-trnE and trnT-trnL) of chloroplast DNA, alone and in combination, were analysed using Bayesian and parsimony methods. Divergence times for major clades were estimated with penalized likelihood. Character evolution was examined by means of parsimony optimization and MacClade. KEY RESULTS: Parsimony and Bayesian phylogenetic analyses on the combined data demonstrated well-resolved species relationships in which 18 Vigna species were divided into two major geographical clades: the East Asia-Southeast Asian clade and the Indian subcontinent clade. Within these two clades, three well-supported eco-geographical groups, temperate and subtropical (the East Asia-Southeast Asian clade) and tropical (the Indian subcontinent clade), are recognized. The temperate group consists of V. minima, V. nepalensis and V. angularis. The subtropical group comprises the V. nakashimae-V. riukiuensis-V. minima subgroup and the V. hirtella-V. exilis-V. umbellata subgroup. The tropical group contains two subgroups: the V. trinervia-V. reflexo-pilosa-V. trilobata subgroup and the V. mungo-V. grandiflora subgroup. An evolutionary rate analysis estimated the divergence time between the East Asia-Southeast Asia clade and the Indian subcontinent clade as 3·62 ± 0·3 million years, and that between the temperate and subtropical groups as 2·0 ± 0·2 million years. CONCLUSIONS: The findings provide an improved understanding of the interspecific relationships, and ecological and geographical phylogenetic structure of the subgenus Ceratotropis. The quaternary diversification of the subgenus Ceratotropis implicates its geographical dispersal in the south-eastern part of Asia involving adaptation to climatic condition after the collision of the Indian subcontinent with the Asian plate. The phylogenetic results indicate that the epigeal germination is plesiomorphic, and the germination type evolved independently multiple times in this subgenus, implying its limited taxonomic utility.


Assuntos
Evolução Molecular , Fabaceae/classificação , Fabaceae/genética , Sudeste Asiático , Sequência de Bases , DNA de Cloroplastos/genética , DNA Intergênico/genética , Ásia Oriental , Dados de Sequência Molecular , Filogenia , Filogeografia
17.
Dent Mater J ; 40(1): 61-67, 2021 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32848101

RESUMO

Binary Ti-Fe alloys of varying concentrations of Fe between 5-25% were made, and their castings evaluated in terms of microstructures formed and mechanical properties. The aim of this study was to explore the composition of Ti-Fe alloys that offers improved wear resistance of titanium. X-ray diffraction and microstructural observation revealed that 5-7% Fe, 8-15% Fe, and 20-25% Fe consisted of α+ß, single ß, and ß+Ti-Fe phases, respectively. The hardness of alloys with 8-13% Fe was almost equal to that of Co-Cr alloys but lower than of the other Ti-Fe alloys. Elongation of the Ti-Fe alloys was negligible. However, dimples were observed in specimen containing 7-11% Fe. Alloys with 9% Fe demonstrated the highest strength of more than 850 MPa. We believe that Ti-Fe alloys with 8-11% Fe may be applicable in development of an alloy with good wear resistance due to the exhibited properties of high hardness and ductility albeit low.


Assuntos
Ligas , Titânio , Ligas Dentárias , Dureza , Teste de Materiais , Resistência à Tração , Difração de Raios X
18.
Dent Mater J ; 40(1): 68-73, 2021 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32848102

RESUMO

Binary Ti-Fe alloys with 5-25 mass% Fe were prepared, and subjected to reciprocating wear test. The aim of this study was to investigate the relationship between mechanical properties and the wear resistance of titanium and Ti-Fe alloys. The dimensions (length, width and depth) of wear marks on Ti-Fe alloys were less than those observed on pure Ti specimen. Wear resistance of Ti-Fe alloys was better than that of pure titanium. It was established that hardness was the main factor that influenced wear resistance of Ti-Fe alloys. Single ß Ti-Fe alloys showed better wear resistance than α+ß Ti-Fe alloys. Increase in concentration of Fe in the ß phase of Ti-Fe alloys leads to improved wear resistance of the alloy. Ti-Fe alloys with 11-15 mass% Fe form ideal candidates for fabrication of dental titanium alloys with excellent wear resistance.


Assuntos
Ligas Dentárias , Titânio , Ligas , Dureza , Teste de Materiais
19.
Chemistry ; 16(33): 10150-9, 2010 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-20645347

RESUMO

The synthesis of a protected dephosphofostriecin, and thereby a formal synthesis of fostriecin, has been accomplished. The synthetic challenges were the construction of four stereogenic centers and the conformationally labile cis-cis-trans-triene moiety. Previous total syntheses have employed at least two asymmetric reactions that required the use of an external chiral auxiliary. Although remote stereoinduction in a 1,4-relationship is considered difficult, we have developed a notable 1,4-asymmetric induction that utilizes an alkyne-cobalt complex for the control of C5 stereochemistry by the C8 stereogenic center. The stereochemistry at C11 was established by 1,3-asymmetric induction with a higher-order alkynyl-zinc reagent. Thus, only one asymmetric reaction requiring an external chiral auxiliary was employed in this route. The labile cis-cis-trans-triene unit was constructed at a late stage of the synthesis by diastereoselective coupling of a dienyne and an aldehyde unit, followed by reduction.


Assuntos
Alcinos/química , Cobalto/química , Polienos/síntese química , Pironas/síntese química , Catálise , Estrutura Molecular , Compostos Organometálicos/química , Polienos/química , Pironas/química , Estereoisomerismo , Streptomyces/química
20.
Biol Pharm Bull ; 33(7): 1250-2, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20606323

RESUMO

The blood-brain barrier (BBB) expresses transporters that influence both dopaminergic neuronal function and drug therapy for Parkinson's disease (PD). The purpose of the present study was to clarify changes of transporter mRNA expression at the BBB in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as a model of PD, in order to understand the pathophysiological role of BBB transport function in PD. At 7 d after MPTP treatment, mice showed a motor deficit and a loss of dopaminergic neurons. At the same time, L-type amino acid transporter 1 (LAT1) mRNA expression in the brain capillary fraction of the MPTP-treated mice was significantly reduced by 62.6% compared with saline-treated mice, while no significant change was observed in the expression of glucose transporter 1, creatine transporter 1, taurine transporter, organic cation transporter 2, serotonin transporter, norepinephrine transporter and dopamine transporter. LAT1 mRNA expression in whole brain was not affected at 1, 3 and 5 d after the treatment, but was reduced by 46.3% at 7 d. LAT1 mediates the transport of large neutral amino acids, including tyrosine, as well as the PD-therapeutic drug levodopa, across the BBB. Our findings indicate that decreased LAT1 expression at the BBB in PD patients may adversely affect amino acid supply from the circulating blood and levodopa distribution into the brain.


Assuntos
Sistemas de Transporte de Aminoácidos/genética , Encéfalo/irrigação sanguínea , Capilares/metabolismo , Modelos Animais de Doenças , Doença de Parkinson/metabolismo , RNA Mensageiro/genética , Animais , Sequência de Bases , Primers do DNA , Camundongos
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