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1.
Materials (Basel) ; 16(13)2023 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-37445177

RESUMO

Anchor bolts are often used for fixing information boards, supports, and soundproof walls in various facilities. Corrosion of anchor bolts and fatigue cracks occur frequently due to the various external environments, and visual inspection and hammering inspection are mainly used. In visual inspection, it is difficult to confirm corrosion or fatigue cracks of anchor bolts in the area where foundations, nuts, and base plates are installed. Additionally, the hammering inspection is easily affected by the surrounding environment and the subjective reaction of the tester. Therefore, it is necessary to develop a method that can easily and accurately detect defects such as cracks and corrosion occurring in anchor bolts installed in road facilities using non-destructive testing techniques. In this paper, the possibility and reliability of anchor bolt defects such as corrosion and cracks were experimentally verified by applying ultrasonic inspection among non-destructive inspection techniques for anchor bolt maintenance.

2.
ACS Appl Mater Interfaces ; 13(19): 22926-22934, 2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-33960762

RESUMO

Recently, wearable sensors, due to their ability to exhibit characteristics, have been appealing for health monitoring through detection of human motions and vital signals. The development of strain sensors with high sensing performance and wearability has been a great challenge to date. In this study, a textile-based strain sensor with good skin affinity was fabricated through a simple fabrication process of dip-coating 2D triaxial-braided fabrics using carbon ink and then drying. The macro crack aligned on the 2D triaxial-braided fabric with a high-density structure and good recovery force. The sensitivity of textile-based strain sensor can be enhanced due to aligned macro crack formed by prestrained fabricating process and characteristic of the 2D triaxial braided fabric with high dense structure. The optimized sensor exhibits high sensitivity (gauge factor: 128) in a strain range of 0-30%, durability (5000 cycles), washability, low hysteresis, and fast response time (90 ms). Therefore, it can be applied as a wearable sensor that can monitor human motions (large strain) and biosignals (subtle strain).


Assuntos
Carbono/química , Monitorização Fisiológica/instrumentação , Dispositivos Eletrônicos Vestíveis , Humanos , Têxteis
3.
ACS Omega ; 6(3): 1960-1970, 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33521436

RESUMO

The objective of this study is to fabricate an electrode by frictional sliding caused by a rough paper surface. The pressure exerted during drawing induces adsorption of the graphite particles by the rough paper and simultaneously reduces the surface roughness of the paper electrode. Repetitive drawing in one-way direction reduced the roughness of the paper surface, decreasing the grain boundaries of graphite. This increases the electron pathway at the electrode, thus reducing the resistance to less than 50 Ω. At the same time, repetitive drawing could confirm that unstable errors caused by the hand could help converge within a certain margin of error. We quantified the relationship between pressure and resistance when drawing on the electrode using a pencil hardness tester. In addition, the electrodes formed by repeated drawing generated a new surface grain and boundary, parallel to the drawing direction, and changed the electrode characteristics with respect to the drawing direction. The grain boundary difference based on the drawing direction was measured via a heating test of the foldable device, a sound pressure level, and laser scattering vibrometer measurements of a linear speaker. The fabricated graphite electrodes can be used in disposable foldable paper electronics because they are prepared using inexpensive materials.

4.
Biomedicines ; 8(6)2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32498454

RESUMO

Patients with dementia suffer from psychological symptoms such as depression, agitation, and aggression. One purpose of dementia intervention is to manage patients' inappropriate behaviors and psychological symptoms while taking into consideration their quality of life (QOL). Animal-assisted intervention (AAI) and pet-robot intervention (PRI) are effective intervention strategies for older people with cognitive impairment and dementia. In addition, AAI and PRI have been shown to have positive effects on behavioral and psychological symptoms of dementia (BPSD). However, studies into the association between AAI/PRI and BPSD have elicited inconsistent results. Thus, we performed a meta-analysis to investigate this association. We analyzed nine randomized controlled trials on AAI and PRI for dementia patients published between January 2000 and August 2019 and evaluated the impact of AAI/PRI on agitation, depression, and QOL. We found that AAI and PRI significantly reduce depression in patients with dementia. Subsequent studies should investigate the impact of AAI and PRI on the physical ability and cognitive function of dementia patients and conduct a follow-up to investigate their effects on the rate of progression and reduction of symptoms of dementia. Our research will help with neuropsychological and environmental intervention to delay or improve the development and progression of BPSD.

5.
Artigo em Inglês | MEDLINE | ID: mdl-27483298

RESUMO

There has been increased deconstruction and demolition of reinforced concrete structures due to the aging of the structures and redevelopment of urban areas resulting in the generation of massive amounts of construction. The production volume of waste concrete is projected to increase rapidly over 100 million tons by 2020. However, due to the high cement paste content, recycled aggregates have low density and high absorption ratio. They are mostly used for land reclamation purposes with low added value instead of multiple approaches. This study was performed to determine an effective method to remove cement paste from recycled aggregates by using the abrasion and substituting the process water with acidic water. The aim of this study is to analyze the quality of the recycled fine aggregates produced by a complex method and investigate the optimum manufacturing conditions for recycled fine aggregates based on the design of experiment. The experimental parameters considered were water ratio, coarse aggregate ratio, and abrasion time and, as a result of the experiment, data concerning the properties of recycled sand were obtained. It was found that high-quality recycled fine aggregates can be obtained with 8.57 min of abrasion-crusher time and a recycled coarse aggregate ratio of over 1.5.


Assuntos
Materiais de Construção , Resíduos Industriais/análise , Melhoria de Qualidade , Reciclagem/métodos , Ácidos Sulfúricos/química , Dióxido de Silício , Água
6.
Appl Opt ; 55(9): 2457-62, 2016 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-27140588

RESUMO

This paper presents a micro-optical pattern-based selective transmission mechanism with a simple modulation principle. The mechanism is composed of a patterned plate and liquid medium, and it does not contain a transparent conductor. The pattern uses 50 µm rectangular pyramid shapes that satisfy a retro-reflection condition. An ultraprecision diamond-cutting machine is used to precisely fabricate the metallic patterned mold, and a hot embossing process creates the micro-optical pattern. The measurement results show that the proposed mechanism displays a much higher optical performance and more durability than the existing switchable glasses in the specific condition. It has specular transmittances of 84.1% in the transparent state and 0.2% in the translucent state, and its total reflectance is 50.4%. An optical simulation verifies the measurement results with a specific analysis.

7.
Materials (Basel) ; 9(5)2016 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-28773470

RESUMO

CO2 emitted from building materials and the construction materials industry has reached about 67 million tons. Controls on the use of consumed fossil fuels and the reduction of emission gases are essential for the reduction of CO2 in the construction area as one reduces the second and third curing to emit CO2 in the construction materials industry. In this study, a new curing method was addressed by using a low energy curing admixture (LA) in order to exclude autoclave curing. The new curing method was applied to make panels. Then, its physical properties, depending on the mixed amount of fiber, type of fiber and mixed ratio of fiber, were observed. The type of fiber did not appear to be a main factor that affected strength, while the LA mixing ratio and mixing amount of fiber appeared to be major factors affecting the strength. Applying the proposed new curing method can reduce carbon and restrain the use of fossil fuels through a reduction of the second and third curing processes, which emit CO2 in the construction materials industry. Therefore, it will be helpful to reduce global warming.

8.
Materials (Basel) ; 9(7)2016 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-28773711

RESUMO

There have been frequent cases of civil complaints and disputes in relation to floor impact noises over the years. To solve these issues, a substantial amount of sound resilient material is installed between the concrete slab and the foamed concrete during construction. A new place-type resilient material is made from cement, silica powder, sodium sulfate, expanded-polystyrene, anhydrite, fly ash, and acrylic polymer emulsion resin. Its physical characteristics such as density, compressive strength, dynamic stiffness, and remanent strain are analyzed to assess the acoustic performance of the material. The experimental results showed the density and the dynamic stiffness of the proposed resilient material is increased with proportional to the use of cement and silica powder due to the high contents of the raw materials. The remanent strain, related to the serviceability of a structure, is found to be inversely proportional to the density and strength. The amount of reduction in the heavyweight impact noise is significant in a material with high density, high strength, and low remanent strain. Finally, specimen no. R4, having the reduction level of 3 dB for impact ball and 1 dB for bang machine in the single number quantity level, respectively, is the best product to obtain overall acoustic performance.

9.
Mol Med Rep ; 7(1): 127-33, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23064235

RESUMO

Protamine from salmon spermaries is a novel dietary protein. Chitooligosaccharide (COS) is an oligosaccharide derived from chitin or chitosan, a long-chain polymer, by chemical or enzymatic hydrolysis. These two compounds are known to enhance lipid metabolism by interrupting the digestion and absorption of fat in the body. Cardiovascular disease (CVD) refers to any type of specific disease that affects the heart and circulatory system. Dyslipidemia, a condition involving high levels of low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol, is generally known to be a primary cause of CVD development. The risk of CVD is usually associated with the atherogenic index (AI) and cardiac risk factor (CRF). The CVD risk is also closely associated with serum levels of total cholesterol (T-CHO), LDL cholesterol and HDL cholesterol. In the present study, we evaluated alterations in serum lipid contents following the administration of protamine, COS and mixtures of these two compounds to male Sprague-Dawley (SD) rats, and their ability to reduce CVD risk. Based on the results of a serum lipid assay, protamine, COS and their mixtures were found to significantly reduce AI, CRF and CVD risk by decreasing serum levels of TG, T-CHO and LDL cholesterol and increasing serum HDL cholesterol levels. By contrast, TG and T-CHO concentrations in feces were markedly increased. Accumulation of lipids in the liver tissues of the SD rats fed high-fat diets was also inhibited by the intake of protamine and COS. Our findings suggest that protamine, COS and combinations of the two compounds may be used as a dietary therapy for preventing CVD due to their suppressive effects on hyperlipidemia and hypercholesterolemia.


Assuntos
Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/prevenção & controle , Quitosana/química , Suplementos Nutricionais , Oligossacarídeos , Protaminas , Animais , Dieta Hiperlipídica , Modelos Animais de Doenças , Metabolismo dos Lipídeos , Lipídeos/sangue , Fígado/metabolismo , Fígado/patologia , Masculino , Ratos , Ratos Sprague-Dawley , Fatores de Risco
10.
Lab Anim Res ; 28(1): 31-8, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22474472

RESUMO

Overweight and obesity are usually related with high fat and calorie intake, and seriously causative of lifestyle-related diseases such as cardiovascular disorders, arteriosclerosis, and colon cancer. In this study, we propose a novel dietary therapy against overweight and obesity using mixtures of protamine and chitooligosaccharide (COS), which are known to interrupt the lipid metabolism in the body. Protamine is a dietary protein originated from salmon reproductive organ, and COS is an oligosaccharide made from chitin or chitosan by chemical or enzymatic hydrolysis. In the enzyme activity analysis in vitro, protamine and COS strongly suppressed the activity of pancreatic lipase, which is the primary enzyme for the digestion and absorption of lipids in the intestine. In in vivo animal test, the mixtures of protamine and COS significantly reduced the serum levels of triglyceride (TG), total cholesterol (T-CHO), and low density lipoprotein-cholesterol (LDLC) and inhibited the accumulation of lipids in liver tissue of Sprague Dawley (SD) rats fed high fat diets. On the other hand, they increased fecal TG and T-CHO contents. From these alterations in lipid metabolism, we verified that protamine and COS mixtures could effectively interrupt the digestion and absorption of dietary lipids in the body by inhibiting pancreatic lipase activity. In addition, protamine and COS mixtures increased the serum level of high density lipoprotein-cholesterol (HDLC), responsible for removing cholesterol from cells and protecting atherosclerosis, and therefore decreased the potential risks of cardiovascular diseases by lowering values of the atherogenic index (AI) and cardiac risk factor (CRF). Taken together, we suggest protamine and COS mixtures as a prominent dietary therapy for the prevention of overweight, obesity, and further cardiovascular diseases related with hyperlipidemia.

11.
Food Chem Toxicol ; 49(9): 2453-8, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21745528

RESUMO

In the present study, we examined the effect of a mixture of dietary components, including red grape extract, soy isoflavone and L-carnitine (RISC), on obesity. RISC substantially inhibited high-fat diet (HFD)-induced increase in body weight in a dose-dependent manner in C57BL/6 mice. The amount of subcutaneous and mesenteric fat was also significantly decreased by RISC treatment in HFD-fed C57BL/6 mice, whereas epididymal fat was not affected. Moreover, HFD-induced plasma leptin levels were down-regulated by RISC treatment. In these mice, RISC treatment significantly increased the plasma level of high density lipoprotein cholesterol without affecting the level of low density lipoprotein cholesterol and triglycerides. In addition, HFD-induced increase in liver weight and lipid accumulation in liver was significantly suppressed by RISC treatment in C57BL/6mice. Plasma level of glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase was also inhibited by RISC treatment. These results demonstrate that RISC suppresses HFD-induced obesity and suggest that RISC supplementation might be a promising adjuvant therapy for the treatment of obesity and its complications, such as cardiovascular and non-alcoholic fatty liver diseases.


Assuntos
Doenças Cardiovasculares/prevenção & controle , Carnitina/farmacologia , Gorduras na Dieta/administração & dosagem , Fígado Gorduroso/prevenção & controle , Glycine max/química , Isoflavonas/farmacologia , Obesidade/prevenção & controle , Extratos Vegetais/farmacologia , Vitis/química , Animais , Lipídeos/sangue , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/etiologia , Tamanho do Órgão/efeitos dos fármacos
12.
Phytother Res ; 25(12): 1789-95, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21480410

RESUMO

To develop a therapeutic agent for obesity-related metabolic disorders, a mixture of dietary components was prepared, including grape extract, green tea extract and l-carnitine (RGTC), and its effects on obesity, hyperlipidemia and non-alcoholic fatty liver disease examined. The RGTC dramatically inhibited the high-fat diet (HFD)-induced increase in body weight and fat in C57BL/6 mice, whereas food consumption was not affected by RGTC treatment. The RGTC also concentration-dependently suppressed the HFD-induced increase in plasma lipids, such as low-density lipoprotein cholesterol and triglycerides. In addition, increases in liver weight and liver steatosis were returned to normal by RGTC treatment in HFD-fed C57BL/6 mice. The plasma levels of glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase were also significantly down-regulated by RGTC treatment. These results suggest that RGTC suppressed HFD-induced obesity, hyperlipidemia and non-alcoholic fatty liver disease, suggesting that RGTC supplementation might be a promising adjuvant therapy for the treatment of these metabolic disorders.


Assuntos
Carnitina/farmacologia , Fígado Gorduroso/tratamento farmacológico , Hiperlipidemias/tratamento farmacológico , Obesidade/tratamento farmacológico , Extratos Vegetais/farmacologia , Tecido Adiposo/efeitos dos fármacos , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Peso Corporal/efeitos dos fármacos , Dieta Hiperlipídica , Leptina/sangue , Lipídeos/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica , Chá/química , Vitis/química
13.
J Med Food ; 14(4): 334-43, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21303262

RESUMO

A combination of green tea extract and l-theanine (LGNC-07) has been reported to have beneficial effects on cognition in animal studies. In this randomized, double-blind, placebo-controlled study, the effect of LGNC-07 on memory and attention in subjects with mild cognitive impairment (MCI) was investigated. Ninety-one MCI subjects whose Mini Mental State Examination-K (MMSE-K) scores were between 21 and 26 and who were in either stage 2 or 3 on the Global Deterioration Scale were enrolled in this study. The treatment group (13 men, 32 women; 57.58 ± 9.45 years) took 1,680 mg of LGNC-07, and the placebo group (12 men, 34 women; 56.28 ± 9.92 years) received an equivalent amount of maltodextrin and lactose for 16 weeks. Neuropsychological tests (Rey-Kim memory test and Stroop color-word test) and electroencephalography were conducted to evaluate the effect of LGNC-07 on memory and attention. Further analyses were stratified by baseline severity to evaluate treatment response on the degree of impairment (MMSE-K 21-23 and 24-26). LGNC-07 led to improvements in memory by marginally increasing delayed recognition in the Rey-Kim memory test (P = .0572). Stratified analyses showed that LGNC-07 improved memory and selective attention by significantly increasing the Rey-Kim memory quotient and word reading in the subjects with MMSE-K scores of 21-23 (LGNC-07, n = 11; placebo, n = 9). Electroencephalograms were recorded in 24 randomly selected subjects hourly for 3 hours in eye-open, eye-closed, and reading states after a single dose of LGNC-07 (LGNC-07, n = 12; placebo, n = 12). Brain theta waves, an indicator of cognitive alertness, were increased significantly in the temporal, frontal, parietal, and occipital areas after 3 hours in the eye-open and reading states. Therefore, this study suggests that LGNC-07 has potential as an intervention for cognitive improvement.


Assuntos
Transtornos Cognitivos/tratamento farmacológico , Glutamatos/uso terapêutico , Memória/efeitos dos fármacos , Fitoterapia , Extratos Vegetais/uso terapêutico , Chá/química , Idoso , Atenção/efeitos dos fármacos , Método Duplo-Cego , Combinação de Medicamentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos
14.
Proc Natl Acad Sci U S A ; 105(26): 9087-92, 2008 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-18579781

RESUMO

Neuroligin-1 is a potent trigger for the de novo formation of synaptic connections, and it has recently been suggested that it is required for the maturation of functionally competent excitatory synapses. Despite evidence for the role of neuroligin-1 in specifying excitatory synapses, the underlying molecular mechanisms and physiological consequences that neuroligin-1 may have at mature synapses of normal adult animals remain unknown. By silencing endogenous neuroligin-1 acutely in the amygdala of live behaving animals, we have found that neuroligin-1 is required for the storage of associative fear memory. Subsequent cellular physiological studies showed that suppression of neuroligin-1 reduces NMDA receptor-mediated currents and prevents the expression of long-term potentiation without affecting basal synaptic connectivity at the thalamo-amygdala pathway. These results indicate that persistent expression of neuroligin-1 is required for the maintenance of NMDAR-mediated synaptic transmission, which enables normal development of synaptic plasticity and long-term memory in the amygdala of adult animals.


Assuntos
Tonsila do Cerebelo/metabolismo , Medo/fisiologia , Potenciação de Longa Duração , Proteínas de Membrana/metabolismo , Memória/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Tonsila do Cerebelo/citologia , Animais , Moléculas de Adesão Celular Neuronais , Ativação do Canal Iônico , Masculino , Proteínas de Membrana/deficiência , Proteínas do Tecido Nervoso/deficiência , Células Piramidais/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/metabolismo , Transmissão Sináptica , Tálamo/metabolismo
15.
Anticancer Drugs ; 19(4): 381-9, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18454048

RESUMO

9-anilinoacridine contains a tricyclic and planar aromatic structure that enables DNA intercalation and inhibition of topoisomerase II. Two recently developed sulfide derivatives of 9-anilinoacridines, 2-({4-[4-(acridin-9-ylamino)phenylthio]phenyl}(2-hydroxyethyl)amino)ethan-1-ol (CK0402) and 3-({4-[4-(acridin-9-ylamino)phenylthio]phenyl}(3-hydroxypropyl)amino)propan-1-ol (CK0403), displayed potent cytotoxic activity in multiple cancer cell lines. In-vitro enzymatic assay demonstrated that CK0402 and CK0403 directly inhibit decatenation reaction of topoisomerase IIalpha. Cells exposed to CK0403 showed DNA fragmentation, and activation of caspase-3 and caspase-2, indicating that it triggers caspase-dependent apoptosis. This was further supported by the fact that cytotoxicity of these drugs is attenuated by pharmacological inhibition of caspases with z-VAD-FMK. Studies with wild-type and p53 primary mouse embryonic fibroblasts demonstrated that p53 does not play a significant role in cell death process initiated by this kind of drug. In addition, pharmacological inhibition of poly(ADP-ribose) polymerase-1activity moderately enhanced cytotoxic activity of sulfide 9-anilinoacridine, suggesting that poly(ADP-ribose) polymerase-1 may have a protective function against 9-anilinoacridine-induced cell death process.


Assuntos
Acridinas/farmacologia , Antineoplásicos/farmacologia , Apoptose , Caspases/fisiologia , Sulfetos/farmacologia , Animais , Western Blotting , Linhagem Celular Transformada , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Fragmentação do DNA/efeitos dos fármacos , DNA Topoisomerases Tipo II/metabolismo , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Camundongos , Inibidores de Poli(ADP-Ribose) Polimerases , Poli(ADP-Ribose) Polimerases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Inibidores da Topoisomerase II , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/fisiologia
16.
Photodermatol Photoimmunol Photomed ; 23(5): 155-62, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17803593

RESUMO

BACKGROUND: Naturally occurring antioxidants were used to regulate the skin damage caused by ultraviolet (UV) radiation because several antioxidants have demonstrated that they can inhibit wrinkle formation through prevention of matrix metalloproteinases (MMPs) and/or increase of collagen synthesis. OBJECTIVE: We examined the effect of oral administration of the antioxidant mixture of vitamin C, vitamin E, pycnogenol, and evening primrose oil on UVB-induced wrinkle formation. In addition, we investigated the possible molecular mechanism of photoprotection against UVB through inhibition of collagen-degrading MMP activity or through enhancement of procollagen synthesis in mouse dorsal skin. METHODS: Female SKH-1 hairless mice were orally administrated the antioxidant mixture (test group) or vehicle (control group) for 10 weeks with UVB irradiation three times a week. The intensity of irradiation was gradually increased from 30 to 180 mJ/cm2. Microtopographic and histological assessment of the dorsal skins was carried out at the end of 10 weeks to evaluate wrinkle formation. Western blot analysis and EMSA were also carried out to investigate the changes in the balance of collagen synthesis and collagen degradation. RESULTS: Our antioxidant mixture significantly reduced UVB-induced wrinkle formation, accompanied by significant reduction of epidermal thickness, and UVB-induced hyperplasia, acanthosis, and hyperkeratosis. This antioxidant mixture significantly prevented the UVB-induced expressions of MMPs, mitogen-activated protein (MAP) kinase, and activation of activator protein (AP)-1 transcriptional factor in addition to enhanced type I procollagen and transforming growth factor-beta2 (TGF-beta2) expression. CONCLUSION: Oral administration of the antioxidant mixture significantly inhibited wrinkle formation caused by chronic UVB irradiation through significant inhibition of UVB-induced MMP activity accompanied by enhancement of collagen synthesis.


Assuntos
Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Flavonoides/farmacologia , Ácidos Linoleicos/farmacologia , Óleos de Plantas/farmacologia , Envelhecimento da Pele/efeitos dos fármacos , Raios Ultravioleta , Vitamina E/farmacologia , Ácido gama-Linolênico/farmacologia , Administração Oral , Animais , Antioxidantes/administração & dosagem , Ácido Ascórbico/administração & dosagem , Flavonoides/administração & dosagem , Ácidos Linoleicos/administração & dosagem , Camundongos , Camundongos Pelados , Oenothera biennis , Extratos Vegetais , Óleos de Plantas/administração & dosagem , Vitamina E/administração & dosagem , Ácido gama-Linolênico/administração & dosagem
17.
Int J Oncol ; 30(2): 341-8, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17203215

RESUMO

von Hippel Lindau (VHL) disease is a hereditary cancer syndrome caused by biallelic inactivation of the VHL tumor suppressor gene. The most widely known function of VHL is to limit normoxic protein expression of hypoxia-inducible factor-alpha (HIF-alpha). Loss of the functional VHL gene causes constitutive stabilization of HIF-alpha that primarily up-regulates hypoxia-inducible genes even at normal oxygen concentration, which in turn contribute to VHL tumor progression. We report on the novel function of VHL in hepatic glucose storage and disposal. VHL deletion in adult mouse liver quickly leads to increased accumulation of glycogen granules as well as lipid droplets. This abnormal glycogen storage in VHL-inactivated liver arises at least in part from significantly reduced expression of two key liver-specific glucose metabolism genes, glucose transporter-2 (GLUT2) and glucose-6-phosphatase (G-6-Pase). The expression pattern of these genes in VHL knock-out liver was in contrast to that of well-known HIF target genes, such as PGK, Glut-1, VEGF, and EPO, all of which are highly elevated upon VHL inactivation. Our findings suggest that two distinct signaling pathways exist at the downstream of VHL controlling different sets of gene expression. Following VHL inactivation, one pathway causes oxygen-independent overexpression of classic hypoxia-inducible genes and the other one described here suppresses expression of the genes important for liver glucose metabolism.


Assuntos
Regulação Neoplásica da Expressão Gênica , Transportador de Glucose Tipo 2/metabolismo , Glucose-6-Fosfatase/metabolismo , Glucose/metabolismo , Fígado/metabolismo , Proteína Supressora de Tumor Von Hippel-Lindau/fisiologia , Alelos , Animais , Primers do DNA/química , Deleção de Genes , Genótipo , Glicogênio/metabolismo , Hipóxia , Imuno-Histoquímica , Camundongos , Oxigênio/metabolismo , Proteína Supressora de Tumor Von Hippel-Lindau/metabolismo
18.
Mol Pharmacol ; 71(3): 942-8, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17178925

RESUMO

HIF-1alpha not only enables cells to survive under hypoxic conditions but also promotes cell cycle arrest and apoptosis. Therefore, its expression should be controlled at optimal levels in growing tumors. We recently reported that bafilomycin A1 exorbitantly expressed HIF-1alpha and induced the p21(WAF1/Cip1)-mediated growth arrest of tumors (Mol Pharmacol 70:1856-1865, 2006). In the present study, we addressed the mechanism underlying bafilomycin-induced HIF-1alpha expression. Bafilomycin stabilized HIF-1alpha under normoxic conditions without changes in intracellular pH. However, when ATP6V0C, the target protein of bafilomycin, was knocked down, this bafilomycin effect was significantly attenuated. Inversely, ATP6V0C expression increased HIF-1alpha levels in a gene dose-dependent manner. ATP6V0C competed with Von Hippel-Lindau protein in HIF-1alpha binding by directly interacting with HIF-1alpha, which was stimulated by bafilomycin. In confocal images, ATP6V0C was normally present in the cytoplasm but was translocated in company with HIF-1alpha to the nucleus by bafilomycin. The N-terminal end (amino acids 1-16) of HIF-1alpha was identified as the ATP6V0C-interacting motif. These results suggest that ATP6V0C, a novel regulator of HIF-1alpha, mediates HIF-1alpha expression by bafilomycin.


Assuntos
Inibidores Enzimáticos/farmacologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Macrolídeos/farmacologia , ATPases Vacuolares Próton-Translocadoras/metabolismo , Proteína Supressora de Tumor Von Hippel-Lindau/metabolismo , Motivos de Aminoácidos , Ligação Competitiva , Humanos , Concentração de Íons de Hidrogênio , Subunidade alfa do Fator 1 Induzível por Hipóxia/química , ATPases Vacuolares Próton-Translocadoras/antagonistas & inibidores
19.
Mol Pharmacol ; 70(6): 1856-65, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16940187

RESUMO

Bafilomycin A1, a macrolide antibiotic isolated from Streptomyces species, has been used as an inhibitor of vacuolar H(+) ATPase (V-ATPase). Bafilomycin has been also evaluated as a potential anticancer agent because it inhibits cell proliferation and tumor growth. Although these anticancer effects of bafilomycin are considered to be attributable to the intracellular acidosis by V-ATPase inhibition, the exact mechanism remains unclear. In the present study, we tested the possibility that bafilomycin targets a tumor-promoting factor, hypoxia-inducible factor-1alpha (HIF-1alpha). Bafilomycin A1 and its analog, concanamycin A, were found to up-regulate HIF-1alpha in eight human cancer cell-lines, and this effect is attributed to inhibited degradation of HIF-1alpha protein. Furthermore, the HIF-1alpha induction by bafilomycin was augmented by hypoxia, which caused a robust induction of p21 and cell cycle arrest in cancer cells. The cell cycle inhibition was shown only in cancer cells expressing both HIF-1alpha and p21. In HIF-1alpha(+/+) or HIF-1alpha(-/-) fibrosarcomas grafted in nude mice, bafilomycin showed the HIF-1alpha-dependent anticancer effect. Based on these results, the exorbitant expression of HIF-1alpha is likely to contribute to the anticancer action of bafilomycin.


Assuntos
Antineoplásicos/farmacologia , Divisão Celular/efeitos dos fármacos , Hipóxia Celular , Subunidade alfa do Fator 1 Induzível por Hipóxia/biossíntese , Macrolídeos/farmacologia , Animais , Western Blotting , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Inibidor de Quinase Dependente de Ciclina p21/biossíntese , Humanos , Imunoprecipitação , Marcação In Situ das Extremidades Cortadas , Masculino , Camundongos , Camundongos Nus , Reação em Cadeia da Polimerase Via Transcriptase Reversa
20.
Nat Med ; 12(7): 793-800, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16799557

RESUMO

Vascular endothelial growth factor (VEGF) exerts crucial functions during pathological angiogenesis and normal physiology. We observed increased hematocrit (60-75%) after high-grade inhibition of VEGF by diverse methods, including adenoviral expression of soluble VEGF receptor (VEGFR) ectodomains, recombinant VEGF Trap protein and the VEGFR2-selective antibody DC101. Increased production of red blood cells (erythrocytosis) occurred in both mouse and primate models, and was associated with near-complete neutralization of VEGF corneal micropocket angiogenesis. High-grade inhibition of VEGF induced hepatic synthesis of erythropoietin (Epo, encoded by Epo) >40-fold through a HIF-1alpha-independent mechanism, in parallel with suppression of renal Epo mRNA. Studies using hepatocyte-specific deletion of the Vegfa gene and hepatocyte-endothelial cell cocultures indicated that blockade of VEGF induced hepatic Epo by interfering with homeostatic VEGFR2-dependent paracrine signaling involving interactions between hepatocytes and endothelial cells. These data indicate that VEGF is a previously unsuspected negative regulator of hepatic Epo synthesis and erythropoiesis and suggest that levels of Epo and erythrocytosis could represent noninvasive surrogate markers for stringent blockade of VEGF in vivo.


Assuntos
Eritropoetina/fisiologia , Fígado/fisiologia , Fator A de Crescimento do Endotélio Vascular/fisiologia , Animais , Hematócrito , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Camundongos Transgênicos , Modelos Animais , Policitemia/fisiopatologia , Receptores de Fatores de Crescimento do Endotélio Vascular/fisiologia , Vasos Retinianos/fisiologia
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