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1.
Heliyon ; 8(11): e11271, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36387451

RESUMO

Background: Familial lecithin: cholesterol acyltransferase (LCAT) deficiency (FLD) is a severe inherited disease without effective treatment. Patients with FLD develop severe low HDL, corneal opacity, hemolytic anemia, and renal injury. Objective: We developed genetically modified adipocytes (GMAC) secreting LCAT (LCAT-GMAC) for ex vivo gene therapy. GMACs were prepared from the patient's adipocytes to express LCAT by retroviral gene transduction to secrete functional enzymes. This study aimed to evaluate the safety and efficacy of LCAT-GMAC implantation in an FLD patient. Methods: Proliferative preadipocytes were obtained from a patient using a ceiling culture and retrovirally transduced with LCAT. After obtaining enough cells by expansion culture of the transduced cells, the resulting LCAT-GMACs were implanted into a patient with FLD. To evaluate the safety and efficacy, we analyzed the outcome of the autologous implantation for 24 weeks of observation and subsequent 240 weeks of the follow-up periods. Results: This first-in-human autologous implantation of LCAT-GMACs was shown to be safe by evaluating adverse events. The LCAT-GMAC implantation increased serum LCAT activity by approximately 50% of the baseline and sustained over three years. Consistent with increased LCAT activity, intermediate-density lipoprotein (IDL) and free cholesterol levels of the small and very small HDL fractions decreased. We found the hemoglobin/haptoglobin complex in the hemolyzed pre-implantation sera of the patient. After one week of the implantation, the hemoglobin/haptoglobin complex almost disappeared. Immediately after the implantation, the patient's proteinuria decreased temporarily to mild levels and gradually increased to the baseline. At 48 weeks after implantation, the patient's proteinuria deteriorated with the development of mild hypertension. By the treatment with antihypertensives, the patient's blood pressure normalized. With the normalization of blood pressure, the proteinuria rapidly decreased to mild proteinuria levels. Conclusions: LCAT-GMAC implantation in a patient with FLD is shown to be safe and appears to be effective, in part, for treating anemia and proteinuria in FLD.

2.
Cells ; 9(6)2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32492819

RESUMO

To identify factors involved in the earliest phase of the differentiation of human embryonic stem cells (hESCs) into brown adipocytes (BAs), we performed multi-time point microarray analyses. We found that growth/differentiation factor 15 (GDF15) expressions were specifically upregulated within three days of differentiation, when expressions of immature hESC markers were sustained. Although GDF15 expressions continued to increase in the subsequent differentiation phases, GDF15-deficient hESCs differentiated into mature BAs (Day 10) without apparent abnormalities. In addition, GDF15-deficient mice had normal brown adipose tissue (BAT) and were metabolically healthy. Unexpectedly, we found that interleukin-6 (IL6) expression was significantly lowered in the BAT of GDF15-/- mice. In addition, GDF15-/- hESCs showed abortive IL6 expressions in the later phase (>Day 6) of the differentiation. Interestingly, GDF15 expression was markedly repressed throughout the whole course of the differentiation of IL6-/- hESCs into BAs, indicating IL6 is essential for the induction of GDF15 in the differentiation of hESCs. Finally, intraperitoneally transplanted BAT grafts of GDF15-/- donor mice, but not those of wild-type (WT) mice, failed in the long-term survival (12 weeks) in GDF15-/- recipient mice. Collectively, GDF15 is required for long-term survival of BAT grafts by creating a mutual gene induction loop with IL6.


Assuntos
Tecido Adiposo Marrom/transplante , Fator 15 de Diferenciação de Crescimento/metabolismo , Interleucina-6/metabolismo , Sobrevivência de Tecidos/fisiologia , Adipócitos Marrons/metabolismo , Animais , Diferenciação Celular/genética , Linhagem Celular , Regulação da Expressão Gênica , Fator 15 de Diferenciação de Crescimento/deficiência , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Camundongos Knockout , Modelos Biológicos
3.
Cells ; 8(4)2019 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-31022954

RESUMO

We previously established a method for a directed differentiation of human pluripotent stem cells into classical brown adipocytes (BA) by forming aggregates via massive floating culture in the presence of a specific cytokine cocktail. However, use of recombinant cytokines requires significant cost. Moreover, an enforced differentiation by exogenously added cytokines may amend skewed differentiation propensity of patient's pluripotent stem cells, providing unsatisfactory disease models. Therefore, an exogenous cytokine-free method, where cytokines required for differentiation are provided in an auto/paracrine manner mimicking natural developmental process, is beneficial. Here we show that, if human pluripotent stem cells are cultured as size-controlled spheroids (100-120 µm radius, 2000-2500 cells/spheroid) in a mutually segregated manner with half-change of the medium every other day, they differentiate into classical BA via an authentic MYF5-positive myoblast route in the absence of exogenous cytokines. Differentiated BA exerted thermogenic activity in transplanted mice in response to beta-adrenergic receptor agonist stimuli. The cytokine-free differentiation method has further advantages in exploring BATokines, BA-derived physiologically active substances. Indeed, we have found that BA produces an unknown small (<1000 Da), highly hydrophilic molecule that augments insulin secretion from pancreatic beta cells. Our upgraded technique will contribute to an advancement of stem cell study for diverse purposes.


Assuntos
Adipócitos Marrons/citologia , Diferenciação Celular/fisiologia , Células-Tronco Pluripotentes/citologia , Adipócitos Marrons/metabolismo , Adipócitos Marrons/fisiologia , Animais , Técnicas de Cultura de Células/métodos , Células Cultivadas , Citocinas/farmacologia , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células Secretoras de Insulina/citologia , Camundongos , Células-Tronco Pluripotentes/metabolismo , Esferoides Celulares/metabolismo , Termogênese
4.
Sci Rep ; 8(1): 14446, 2018 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-30262832

RESUMO

Brown adipose tissue (BAT), which is composed of thermogenic brown adipocytes (BA) and non-parenchymal components including vasculatures and extracellular matrix, contribute to the maintenance of body temperature. BAT distribution is detected by positron emission tomography-computed tomography (PET/CT) using 18F-fluorodeoxy glucose (18F-FDG) or single-photon-emission computed tomography-computed tomography (SPECT/CT) using [123/125I]-beta-methyl-p-iodophenyl-pentadecanoic acid. Although sympathetic nerve activity and thermogenic capacity of BA is downregulated under fasting conditions in mice, fasting-dependent structural changes and fluid kinetics of BAT remain unknown. Here we show that the fasting induces fine and reversible structural changes in the non-parenchymal region in murine BAT with widened intercellular spaces and deformed collagen bands as revealed by electron microscopy. Interestingly, a newly introduced near infrared fluorescent probe of single-walled carbon nanotubes (CNTs) coated with phospholipid polyethylene glycol (PLPEG) easily demonstrated enhanced vascular permeability in BAT by the fasting. PLPEG-CNTs extravasated and remained in intercellular spaces or further redistributed in parenchymal cells in fasted mice, which is a previously unknown phenomenon. Thus, PLPEG-CNTs provide a powerful tool to trace fluid kinetics in sub-tissue levels.


Assuntos
Tecido Adiposo Marrom , Permeabilidade Capilar , Materiais Revestidos Biocompatíveis , Corantes Fluorescentes , Nanotubos de Carbono/química , Imagem Óptica/métodos , Tecido Adiposo Marrom/irrigação sanguínea , Tecido Adiposo Marrom/diagnóstico por imagem , Animais , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Feminino , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus
5.
Anim Sci J ; 89(4): 727-732, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29280539

RESUMO

Changes in mastitis-causing pathogens, pH and water content in composted manure solids (CMS) prepared from digested slurry were evaluated during turning at 2-day intervals for 8 days (C1-C4). The numbers of streptococci, coagulase-negative staphylococci and coliforms were 2.6 × 101 , 1.7 × 102 and 1.0 × 101  colony-forming units (cfu)/g in CMS (C4) (summer), and these counts were markedly lower (P < 0.05) than those in CMS (C0 and C1). The bacterial counts ranged from 101 to 1.7 × 102  cfu/g in CMS (C4) (summer) and were within approved levels, <1 × 106  cfu/g, indicating a minimal mastitis risk. The temperatures in CMS (C1-C4) increased to 63°C-74°C in summer and 67°C-70°C in winter. The mean pH values in CMS (C0-C4) were 9.2 in summer and 8.7 in winter, and water contents ranged from 61.7% to 69.6% in summer and 73.2% to 66.2% in winter. The significant decrease of pathogenic bacteria in CMS appears to be closely related to temperature >63°C for 8 days, pH 8.7-9.2, and water content 62% to 73%. This study demonstrates that prepared CMS has value as a recycled material with the potential to alleviate udder health issues in dairy cows.


Assuntos
Anaerobiose , Abrigo para Animais , Esterco/microbiologia , Animais , Bovinos , Indústria de Laticínios , Enterobacteriaceae/isolamento & purificação , Enterococcus/isolamento & purificação , Escherichia coli/isolamento & purificação , Feminino , Concentração de Íons de Hidrogênio , Mastite Bovina/microbiologia , Risco , Estações do Ano , Streptococcus/isolamento & purificação , Temperatura , Água
6.
World J Virol ; 6(3): 49-52, 2017 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-28868242

RESUMO

The occurrence of lipodystrophy in patients taking anti-human immunodeficiency virus (HIV) medications is a serious problem as it is irreversible even after drug withdrawal. Although it was first recognized in patients taking proteinase inhibitors, other types of anti-HIV agents can also cause lipodystrophy. In a recent publication by Jones et al entitled "Highly active antiretroviral therapy dysregulates proliferation and differentiation of human pre-adipocytes" in World Journal of Virology, it was reported that simultaneous treatment of human subcutaneous adipocytes with anti-HIV drugs with different mechanisms of action synergistically exerted anti-adipogenesis effects in vitro, warning us to take utmost care in every case receiving combination antiretroviral therapy (cART). For elucidation of the molecular basis for cART-related lipodystrophy, multi-faceted approaches should be taken, based on a deeper understanding of the development and organization of adipose tissues.

7.
Nat Commun ; 8(1): 286, 2017 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-28819169

RESUMO

Adipose tissue resident macrophages have important roles in the maintenance of tissue homeostasis and regulate insulin sensitivity for example by secreting pro-inflammatory or anti-inflammatory cytokines. Here, we show that M2-like macrophages in adipose tissue regulate systemic glucose homeostasis by inhibiting adipocyte progenitor proliferation via the CD206/TGFß signaling pathway. We show that adipose tissue CD206+ cells are primarily M2-like macrophages, and ablation of CD206+ M2-like macrophages improves systemic insulin sensitivity, which was associated with an increased number of smaller adipocytes. Mice genetically engineered to have reduced numbers of CD206+ M2-like macrophages show a down-regulation of TGFß signaling in adipose tissue, together with up-regulated proliferation and differentiation of adipocyte progenitors. Our findings indicate that CD206+ M2-like macrophages in adipose tissues create a microenvironment that inhibits growth and differentiation of adipocyte progenitors and, thereby, control adiposity and systemic insulin sensitivity.Adipose tissue contains macrophages that can influence both local and systemic metabolism via the secretion of cytokines. Here, Nawaz et al. report that M2-like macrophages, present in adipose tissue, create a microenvironment that inhibits proliferation of adipocyte progenitors due to the secretion of TGF-ß1.


Assuntos
Adipócitos/citologia , Glucose/metabolismo , Lectinas Tipo C/metabolismo , Macrófagos/metabolismo , Lectinas de Ligação a Manose/metabolismo , Obesidade/metabolismo , Receptores de Superfície Celular/metabolismo , Adipócitos/metabolismo , Adipócitos Brancos/metabolismo , Adipócitos Brancos/patologia , Tecido Adiposo Branco/citologia , Tecido Adiposo Branco/metabolismo , Animais , Diferenciação Celular , Proliferação de Células , Dieta Hiperlipídica/efeitos adversos , Resistência à Insulina , Lectinas Tipo C/genética , Receptor de Manose , Lectinas de Ligação a Manose/genética , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptores de Superfície Celular/genética , Transdução de Sinais , Células-Tronco/citologia , Células-Tronco/metabolismo , Fator de Crescimento Transformador beta/metabolismo
8.
Sci Rep ; 7: 44760, 2017 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-28317858

RESUMO

Near-infrared photoluminescent single-walled carbon nanotubes (CNTs) are expected to provide effectual bio-imaging tools, although, as yet, only limited applications have been reported. Here, we report that CNTs coated with an amphiphilic and biocompatible polymer, poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate; PMB), generate high-quality images of brown fat. Brown fat is a heat-productive adipose tissue, which is attracting increasing attention as a new therapeutic target for obesity-associated metabolic disorders. Its brown colour is mainly attributed to densely packed capillaries, which facilitate its high heat-exchanging efficiency. Currently, positron emission tomography-computed tomography is the only practical technique to identify brown fat distribution in the living body; however, it is expensive to use. By virtue of their high affinity to apolipoproteins and exemption from macrophage phagocytosis, PMB-CNTs selectively accumulate on capillary endothelial cells but not larger vessels in adipose tissue. Therefore, the image brightness of adipose tissue can directly reflect the capillary density, and indirectly the thermogenic capability and brownness. PMB-CNTs provide clearer images than conventional organic dyes, as the high level of transmitted light passes through the body with less light scattering. Thus, PMB-CNT-based imaging methods could open a new phase in thermogenic adipose tissue research.


Assuntos
Tecido Adiposo Marrom/anatomia & histologia , Imageamento Tridimensional , Medições Luminescentes/métodos , Nanotubos de Carbono/química , Espectroscopia de Luz Próxima ao Infravermelho , Tecido Adiposo Marrom/citologia , Tecido Adiposo Marrom/ultraestrutura , Tecido Adiposo Branco/ultraestrutura , Animais , Apolipoproteínas/metabolismo , Células Endoteliais/citologia , Metacrilatos/química , Camundongos Endogâmicos BALB C , Camundongos Nus , Nanotubos de Carbono/ultraestrutura , Fosforilcolina/análogos & derivados , Fosforilcolina/química
9.
Curr Biol ; 25(15): 2026-33, 2015 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-26166782

RESUMO

Centromeres are the chromosomal regions promoting kinetochore assembly for chromosome segregation. In many eukaryotes, the centromere consists of up to mega base pairs of DNA. On such "regional centromeres," kinetochore assembly is mainly defined by epigenetic regulation [1]. By contrast, a clade of budding yeasts (Saccharomycetaceae) has a "point centromere" of 120-200 base pairs of DNA, on which kinetochore assembly is defined by the consensus DNA sequence [2, 3]. During evolution, budding yeasts acquired point centromeres, which replaced ancestral, regional centromeres [4]. All known point centromeres among different yeast species share common consensus DNA elements (CDEs) [5, 6], implying that they evolved only once and stayed essentially unchanged throughout evolution. Here, we identify a yeast centromere that challenges this view: that of the budding yeast Naumovozyma castellii is the first unconventional point centromere with unique CDEs. The N. castellii centromere CDEs are essential for centromere function but have different DNA sequences from CDEs in other point centromeres. Gene order analyses around N. castellii centromeres indicate their unique, and separate, evolutionary origin. Nevertheless, they are still bound by the ortholog of the CBF3 complex, which recognizes CDEs in other point centromeres. The new type of point centromere originated prior to the divergence between N. castellii and its close relative Naumovozyma dairenensis and disseminated to all N. castellii chromosomes through extensive genome rearrangement. Thus, contrary to the conventional view, point centromeres can undergo rapid evolutionary changes. These findings give new insights into the evolution of point centromeres.


Assuntos
Centrômero/genética , DNA Fúngico/genética , Evolução Molecular , Saccharomycetales/genética , Centrômero/metabolismo , DNA Fúngico/metabolismo , Saccharomycetales/metabolismo
10.
Nat Cell Biol ; 14(6): 614-24, 2012 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-22561345

RESUMO

Kinetochores attach the replicated chromosomes to the mitotic spindle and orchestrate their transmission to the daughter cells. Kinetochore-spindle binding and chromosome segregation are mediated by the multi-copy KNL1(Spc105), MIS12(Mtw1) and NDC80(Ndc80) complexes that form the so-called KMN network. KMN-spindle attachment is regulated by the Aurora B(Ipl1) and MPS1(Mps1) kinases. It is unclear whether other mechanisms exist that support KMN activity during the cell cycle. Using budding yeast, we show that kinetochore protein Cnn1 localizes to the base of the Ndc80 complex and promotes a functionally competent configuration of the KMN network. Cnn1 regulates KMN activity in a spatiotemporal manner by inhibiting the interaction between its complexes. Cnn1 activity peaks in anaphase and is driven by the Cdc28, Mps1 and Ipl1 kinases.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Cinetocoros/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Anáfase , Proteínas de Ciclo Celular/genética , Cromossomos Fúngicos/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Fosforilação , Ligação Proteica , Proteínas Serina-Treonina Quinases/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Fuso Acromático/metabolismo
11.
Phys Rev Lett ; 98(21): 213904, 2007 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-17677774

RESUMO

We performed optical pulse propagation experiments in a system in which two ultrahigh-Q silica microspheres of different diameters were coupled in tandem to a fiber taper to yield coupled-resonator-induced transparency. Nearly Gaussian-shaped optical pulses propagated with a large positive delay of 8.5 ns through a transparent frequency window, without significant attenuation, amplification, or pulse deformation, demonstrating classical analogy of the extremely slow light obtained with electromagnetically induced transparency.

12.
Genes Cells ; 12(3): 375-85, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17352741

RESUMO

c-Ski, originally identified as an oncogene product, induces myogenic differentiation in nonmyogenic fibroblasts through transcriptional activation of muscle regulatory factors. Although c-Ski does not bind to DNA directly, it binds to DNA through interaction with Smad proteins and regulates signaling activities of transforming growth factor-beta (TGF-beta). In the present study, we show that c-Ski activates the myogenin promoter independently of regulation of endogenous TGF-beta signaling. Expression of myogenin is regulated by a transcription factor complex containing proteins of the MyoD family and the myocyte enhancer factor 2 (MEF2) family. c-Ski acts on the MyoD-MEF2 complex and modulates the activity of MyoD in myogenin promoter regulation. Interestingly, histone deacetylase (HDAC) inhibitors up-regulated basal activity of transcription from a MyoD-responsive reporter, although c-Ski failed to further augment this transcription in the presence of HDAC inhibitors. c-Ski is observed both in the cytoplasm and in the nucleus, but its nuclear localization is required for myogenic differentiation. We conclude that c-Ski induces myogenic differentiation through acting on MyoD and inhibiting HDAC activity in the nucleus of myogenic cells.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Histona Desacetilases/metabolismo , Proteína MyoD/metabolismo , Mioblastos Esqueléticos/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Animais , Proteínas Reguladoras de Apoptose , Proteínas de Transporte/metabolismo , Diferenciação Celular , Linhagem Celular , Núcleo Celular/metabolismo , DNA/genética , DNA/metabolismo , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Inibidores de Histona Desacetilases , Fatores de Transcrição MEF2 , Camundongos , Proteínas Mitocondriais/metabolismo , Mioblastos Esqueléticos/citologia , Fatores de Regulação Miogênica/metabolismo , Miogenina/genética , Regiões Promotoras Genéticas , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismo
13.
Genes Cells ; 11(11): 1267-80, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17054724

RESUMO

c-Ski is a proto-oncogene product that induces morphologic transformation, anchorage independence, and myogenic differentiation when it is over-expressed in mesenchymal cells. c-Ski also inhibits signaling of transforming growth factor-beta (TGF-beta) superfamily members through interaction with Smad proteins. Although c-Ski is predominantly localized in the nucleus, aberrant cytoplasmic localization of it has also been reported in some tumor tissues and cell lines. In the present study, we identified the nuclear localization signal (NLS) in c-Ski. By introducing a mutation to abolish NLS activity, we examined the function of cytoplasmic c-Ski. Although cytoplasmic c-Ski suppressed TGF-beta superfamily-induced Smad signaling through sequestration of activated Smad complex to the cytoplasm, it failed to exhibit some of the activities that require nuclear localization of c-Ski, including suppression of basal transcription of the Smad7 gene. These findings indicate that subcellular localization of c-Ski affects its biologic activities. We also found that c-Ski accumulated in the cytoplasm when proteasome activity was inhibited. Mapping of the regions required for cytoplasmic accumulation by proteasome inhibitors suggests that subcellular localization of c-Ski may be regulated by proteasome-sensitive processes through amino acid residues 94-210 and 491-548.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Sequência de Bases , Proteínas Morfogenéticas Ósseas/metabolismo , Células COS , Linhagem Celular , Núcleo Celular/metabolismo , Chlorocebus aethiops , Citoplasma/metabolismo , DNA/genética , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Estabilidade de Medicamentos , Células HeLa , Humanos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Sinais de Localização Nuclear/química , Sinais de Localização Nuclear/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transdução de Sinais , Proteínas Smad/metabolismo , Transfecção , Fator de Crescimento Transformador beta/metabolismo
14.
J Dent ; 33(1): 57-63, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15652169

RESUMO

OBJECTIVES: In order to obtain an insight on the internal stress caused by both polymerization and thermal shrinkage during the fabrication process of heat-cured denture resin, the effect of bench cooling on the dimensional accuracy of a heat-cured denture base resin was examined. METHODS: A dimensional change of a dumbbell-shaped specimen during the fabrication process was measured directly by using the strain gauge method. After polymerization, the specimens were treated in one of the following two processing methods: (1) rapid cooling: the specimen was removed from a stone mold within a container of boiling water at 100 degrees C and then left to cool in a thermo-stabilized room of 20+/-1 degrees C; (2) bench cooling: the flask was left to cool in a thermo-stabilized room of 20+/-1 degrees C for 140min, after which, the specimen was removed from the stone mold. The strain from deflasking was derived from the difference in the strain, before and after the removal of the specimen from the stone mold. The strain differential, before and after cooling, was determined as the total strain. RESULTS: The bench cooling for the heat-cured denture base resin reduced the strain caused by thermal shrinkage during the fabrication process. The observed reduction in the strain was 26% for the C(L) (direction of center's length), 11% for the E(L) (direction of left-edge's length), and 12% for the E(W) (direction of left-edge's width), when compared with the results obtained from the rapid-cooling method. CONCLUSIONS: The flask should be slowly cooled to room temperature, since the internal stress developed by thermal shrinkage will be relaxed during the cooling process.


Assuntos
Resinas Acrílicas , Bases de Dentadura , Análise de Variância , Análise do Estresse Dentário , Teste de Materiais , Transição de Fase , Estresse Mecânico , Temperatura
15.
Blood ; 102(9): 3186-95, 2003 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-12855588

RESUMO

To investigate the roles of c-myc during hematopoietic proliferation induced by growth factors, we used factor-dependent human leukemic cell lines (MO7e and F36P) in which proliferation, cell cycle progression, and c-Myc expression were strictly regulated by granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3). In these cell lines, both c-myc mRNA and c-Myc protein stability were not affected by GM-CSF and IL-3, suggesting a regulation of c-Myc protein at the translational level. However, rapamycin, an inhibitor of cap-dependent translation, did not block c-myc induction by GM-CSF and IL-3. Thus, we studied the cap-independent translation, the internal ribosome entry site (IRES), during c-Myc protein synthesis using dicistronic reporter gene plasmids and found that GM-CSF and IL-3 activated c-myc IRES to initiate translation. c-myc IRES activation, c-Myc protein expression, and cell cycle progression were all blocked by a phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002. In another factor-dependent cell line, UT7, we observed the cell cycle progression and up-regulation of c-Myc protein, c-myc mRNA, and c-myc IRES simultaneously, which were all inhibited by LY294002. Results indicate that hematopoietic growth factors induce cell cycle progression via IRES-mediated translation of c-myc though the PI3K pathway in human factor-dependent leukemic cells.


Assuntos
Ciclo Celular/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/fisiologia , Interleucina-3/fisiologia , Leucemia/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Biossíntese de Proteínas/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-myc/biossíntese , Linhagem Celular Tumoral , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Substâncias de Crescimento/farmacologia , Humanos , Interleucina-3/farmacologia , Iniciação Traducional da Cadeia Peptídica/efeitos dos fármacos , RNA Mensageiro/biossíntese , Ribossomos , Transdução de Sinais , Regulação para Cima/efeitos dos fármacos
16.
Biochem J ; 368(Pt 3): 705-20, 2002 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-12206715

RESUMO

We investigated intracellular signalling pathways for apoptosis induced by epigallocatechin-3-gallate (EGCG) as compared with those induced by a toxic chemical substance (etoposide, VP16) or the death receptor ligand [tumour necrosis factor (TNF)]. EGCG as well as VP16 and TNF induced activation of two apoptosis-regulating mitogen-activated protein (MAP) kinases, namely c-Jun N-terminal kinase (JNK) and p38 MAP kinase, in both human leukaemic U937 and OCI-AML1a cells. In U937 cells, the apoptosis and activation of caspases-3 and -9 induced by EGCG but not VP16 and TNF were inhibited with SB203580, a specific inhibitor of p38, while those induced by EGCG and VP16 but not TNF were inhibited with SB202190, a rather broad inhibitor of JNK and p38. In contrast, the EGCG-induced apoptosis in OCI-AML1a cells was resistant to SB203580 but not to SB202190. Unlike TNF, EGCG did not induce the activation of nuclear factor-kappaB but rather induced the primary activation of caspase-9. N -Acetyl-L-cysteine (NAC) almost completely abolished apoptosis induced by EGCG under conditions in which the apoptosis induced by VP16 or TNF was not affected. The JNK/p38 activation by EGCG was also potently inhibited by NAC, whereas those by VP16 and TNF were either not or only minimally affected by NAC. In addition, dithiothreitol also suppressed both apoptosis and JNK/p38 activation by EGCG, and EGCG-induced activation of MAP kinase kinase (MKK) 3/6, MKK4 and apoptosis-regulating kinase 1 (ASK1) was suppressed by NAC. Dominant negative ASK1, MKK6, MKK4 and JNK1 potently inhibited EGCG-induced cell death. EGCG induced an intracellular increase in reactive oxygen species and GSSG, both of which were also inhibited by NAC, and the decreased synthesis of glutathione rendered the cell susceptible to EGCG-induced apoptosis. Taken together these results strongly suggest that EGCG executed apoptotic cell death via an ASK1, MKK and JNK/p38 cascade which is triggered by NAC-sensitive intracellular oxidative events in a manner distinct from chemically induced or receptor-mediated apoptosis.


Assuntos
Antioxidantes/farmacologia , Catequina/análogos & derivados , Catequina/farmacologia , Flavonoides , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Oxigênio/metabolismo , Apoptose , Western Blotting , Caspase 8 , Caspase 9 , Caspases/metabolismo , Morte Celular , Fragmentação do DNA , Relação Dose-Resposta a Droga , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Etoposídeo/farmacologia , Citometria de Fluxo , Glutationa/metabolismo , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno , MAP Quinase Quinase Quinase 5 , MAP Quinase Quinase Quinases/metabolismo , Sistema de Sinalização das MAP Quinases , Modelos Biológicos , NF-kappa B/metabolismo , Inibidores da Síntese de Ácido Nucleico/farmacologia , Oxirredução , Fenóis/metabolismo , Polímeros/metabolismo , Espécies Reativas de Oxigênio , Transdução de Sinais , Fatores de Tempo , Transfecção , Células Tumorais Cultivadas , Fator de Necrose Tumoral alfa/metabolismo , Células U937 , Ativador de Plasminogênio Tipo Uroquinase/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno
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