Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Ann Palliat Med ; 10(12): 12742-12749, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35016439

RESUMO

BACKGROUND: Atrial fibrosis is a landmark of cardiac remodeling to perpetuate atrial fibrillation (AF), and recent studies have indicated that microRNAs (miRNAs) are essential regulators of multiple cardiovascular disease processes. Herein, we aimed to investigate the relationship between circulating microRNA-21 (miR-21), atrial fibrosis, and AF in patients with atrial enlargement. METHODS: A total of 60 persistent AF patients and 60 matched sinus rhythm (SR) controls were enrolled in the study. We measured their plasma miR-21 levels by using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Then, each patient underwent transthoracic echocardiography (TTE), while persistent AF patients underwent delayed enhancement magnetic resonance imaging (MRI). RESULTS: The plasma miR-21 concentrations in the AF group were significantly higher than in the controls, and highly correlated [R=0.689, 95% confidence interval (CI): 0.527 to 0.802; P<0.001] with left atrial (LA) fibrosis measured by delayed enhancement MRI. Receiver operating characteristics (ROC) curve analysis showed that the area under the curve (AUC) of plasma miR-21 to identify AF was 0.813 (95% CI: 0.731 to 0.878). The increasing levels of circulating miR-21 were significantly associated with the higher risk of AF by using logistic regression analysis, even after adjustment for known confounding variables. CONCLUSIONS: Circulating miR-21 highly correlates with the quantification of LA fibrosis by using delayed enhancement MRI and is associated with the risk of persistent AF in patients with LA enlargement.


Assuntos
Fibrilação Atrial , MicroRNA Circulante , Átrios do Coração , MicroRNAs , Fibrilação Atrial/genética , MicroRNA Circulante/sangue , Fibrose , Átrios do Coração/diagnóstico por imagem , Átrios do Coração/patologia , Humanos , MicroRNAs/sangue
2.
Zhongguo Zhong Yao Za Zhi ; 44(5): 996-1003, 2019 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-30989861

RESUMO

In this study,in-depth systematic evaluation of rat of acute kidney injury(AKI) caused by renal arteriovenous ligation was conducted to better master and apply this model for drug research. Male SD rats of 2-3 months old were employed in this study.The left kidney was removed,and the right kidney received ligation for 40 min and reperfusion for 24 h. Serum creatinine(Crea),urea nitrogen(BUN) and the renal tissue sections were assayed as the basic indicators to evaluate their renal function. The mRNA expression of inflammatory necrosis factors and apoptotic factors was used to evaluate the mechanism of molecular pathophysiological changes. The results showed that the serum Crea and BUN caused by ligation of both renal arteries and veins were significantly higher than those of rats with renal artery ligation. After renal arteriovenous ligation for 40 min and reperfusion for 24 h in rats,the serum Crea of the rats varied from less than 100 µmol·L-1 to more than 430 µmol·L-1. Among them,5 rats showed less than 100 µmol·L-1 serum Crea,20 rats with 100-200 µmol·L-1 serum Crea and 12 rats with more than 430 µmol·L-1. Rats with serum Crea between 300-430 µmol·L-1 accounted for 66.3%(122/184) of the total number of the experiment rats. After 72 h reperfusion,serum Crea in the group of Crea 370-430 µmol·L-1 continued to increase,while the serum Crea in the group of Crea 200-300 µmol·L-1 and the group of Crea 300-370 µmol·L-1 recovered quickly. No matter serum Crea was elevated or decreased,the renal tubules showed pathological changes such as vacuolar degeneration or even necrosis. The mRNA expression levels of Toll-like receptor(TLR4),tumor necrosis factor(TNF-α) and interleukin(IL-6) in renal tissueswere significantly up-regulated,and the effect was most obvious in the group of serum Crea 370-430 µmol·L-1. The study indicated that the model for AKI caused by renal arteriovenous ligation and reperfusion is easy to operate,and the serum Crea and BUN have the characteristics of continuous increase,beneficial to the observation of drug effects. This acute kidney injury is mainly related to the pathophysiological response of inflammatory necrosis.


Assuntos
Injúria Renal Aguda/patologia , Traumatismo por Reperfusão , Animais , Nitrogênio da Ureia Sanguínea , Creatinina/sangue , Modelos Animais de Doenças , Rim/patologia , Túbulos Renais/patologia , Ligadura , Masculino , Ratos , Ratos Sprague-Dawley , Artéria Renal
3.
Medicine (Baltimore) ; 97(25): e11204, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29924045

RESUMO

The aim of this study is to compare the differences in the stress distributions in the temporomandibular joints (TMJs) of the patients with facial asymmetry before and after bilateral sagittal split ramus osteotomy (BSSRO) under the symmetric occlusions using the three-dimensional (3D) finite element method.Ten facial asymmetry patients (Preoperative group, age 24.6 ±â€Š4.8 years) and 10 asymptomatic subjects (Control group, age 26.8 ±â€Š4.9 years) were recruited. After the patients underwent BSSRO, they were further assigned as the Postoperative group. 3D geometries of the finite element models of the mandible, disc, maxilla, and teeth were reconstructed according to cone-beam computed tomography (CBCT) image data. Contact elements were used to simulate the interaction of the disc-condyle, disc-temporal bone, and upper-lower dentition. The muscle forces and boundary conditions corresponding to the central and anterior occlusions were applied on the models of the 3 groups. The finite element models were validated with experimental data showing the accuracy of the simulation results.The simulation predicted preoperative significant differences of stresses between non-deviated sides and deviated sides were disappeared after the surgery under the central and anterior occlusions (P < .05). Almost all stresses in the patient models had significantly decreased after BSSRO, leveling it to the stress values of the normal subjects. Moreover, the simulation results coincided with the clinical cases which showed that BSSRO had helped to release or remove the signs and symptoms of temporomandibular disorders (TMD).In conclusion, BSSRO could correct the asymmetric stress distributions of TMJs and decrease the magnitude of the stresses for the patients with facial asymmetry. Those decreases also associated with the recovery of TMD.


Assuntos
Assimetria Facial/cirurgia , Osteotomia Sagital do Ramo Mandibular/efeitos adversos , Estresse Mecânico , Transtornos da Articulação Temporomandibular/cirurgia , Articulação Temporomandibular/anatomia & histologia , Adulto , Tomografia Computadorizada de Feixe Cônico/métodos , Feminino , Análise de Elementos Finitos , Humanos , Imageamento Tridimensional/métodos , Masculino , Mandíbula/patologia , Mandíbula/cirurgia , Osteotomia Sagital do Ramo Mandibular/métodos , Simulação de Paciente , Período Pós-Operatório , Período Pré-Operatório , Prognatismo/cirurgia , Articulação Temporomandibular/fisiologia , Dente , Adulto Jovem
4.
Medicine (Baltimore) ; 95(13): e3052, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27043669

RESUMO

Signs and symptoms of temporomandibular joint (TMJ) dysfunction are commonly found in patients with facial asymmetry. Previous studies on the TMJ position have been limited to 2-dimensional (2D) radiographs, computed tomography (CT), or cone-beam computed tomography (CBCT). The purpose of this study was to compare the differences of TMJ position by using 2D CBCT and 3D model measurement methods. In addition, the differences of TMJ positions between patients with facial asymmetry and asymptomatic subjects were investigated. We prospectively recruited 5 patients (cases, mean age, 24.8 ±â€Š2.9 years) diagnosed with facial asymmetry and 5 asymptomatic subjects (controls, mean age, 26 ±â€Š1.2 years). The TMJ spaces, condylar and ramus angles were assessed by using 2D and 3D methods. The 3D models of mandible, maxilla, and teeth were reconstructed with the 3D image software. The variables in each group were assessed by t-test and the level of significance was 0.05. There was a significant difference in the horizontal condylar angle (HCA), coronal condylar angle (CCA), sagittal ramus angle (SRA), medial joint space (MJS), lateral joint space (LJS), superior joint space (SJS), and anterior joint space (AJS) measured in the 2D CBCT and in the 3D models (P < 0.05). The case group had significantly smaller SJS compared to the controls on both nondeviation side (P = 0.009) and deviation side (P = 0.004). In the case group, the nondeviation SRA was significantly larger than the deviation side (P = 0.009). There was no significant difference in the coronal condylar width (CCW) in either group. In addition, the anterior disc displacement (ADD) was more likely to occur on the deviated side in the case group. In conclusion, the 3D measurement method is more accurate and effective for clinicians to investigate the morphology of TMJ than the 2D method.


Assuntos
Assimetria Facial/diagnóstico por imagem , Assimetria Facial/patologia , Imageamento Tridimensional/métodos , Articulação Temporomandibular/anatomia & histologia , Articulação Temporomandibular/diagnóstico por imagem , Adulto , Tomografia Computadorizada de Feixe Cônico , Feminino , Humanos , Masculino , Mandíbula/anatomia & histologia , Mandíbula/diagnóstico por imagem , Maxila/anatomia & histologia , Maxila/diagnóstico por imagem , Estudos Prospectivos , Dente/anatomia & histologia , Dente/diagnóstico por imagem
5.
Huan Jing Ke Xue ; 37(1): 366-76, 2016 Jan 15.
Artigo em Chinês | MEDLINE | ID: mdl-27078979

RESUMO

The data on nitrogen gas (NH3, N2O, NO) emissions during sludge bio-drying process in China is scarce, especially NO due to its unstable chemical property. In this study, effect of two aeration modes on emissions of methane and nitrogenous gas was compared during the continuous aerated turning pile sludge bio-drying process at full scale. In these two aeration strategies, the one currently used in the plant was set as the control, and the other was set as the test in which the aeration was used for oxygen supply, pile temperature control, and moisture removal in the start-up, middle and final stages, respectively. The results showed that the aeration strategy used in the test could not only obviously accelerate the rate of sludge drying (the moisture contents of the test and the control were 36.6% and 42% on day 11) , but also had a better drying performance (the final moisture contents of the test and the control were 33.6% and 37.6%, respectively) and decreased the ammonia cumulative emission by 5%, (ammonia cumulative emission of the test and the control were 208 mg x m(-3) and 219.8 mg x m(-3), respectively). Though a lower accumulated emission (eCO2) of greenhouse gas in the test at 3.61 kg x t(-1) was observed than that of the control (3.73 kg x t(-1) dry weight) , the cumulative emission of NO in the test at 1.9 g x m(-2) was 15. 9% higher than that of the control (1.6 g x m(-2)).


Assuntos
Metano/análise , Nitrogênio/análise , Esgotos , Eliminação de Resíduos Líquidos/métodos , Amônia/análise , China , Dessecação , Temperatura
6.
Huan Jing Ke Xue ; 35(7): 2798-806, 2014 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-25244871

RESUMO

There is a lack of observation data on greenhouse gas (GHG) and ammonia emissions from sewage sludge composting, though the emissions can result in environmental issue and nitrogen loss. In this study, GHG and ammonia emissions were monitored under different operating parameters during sludge composting with continuous aerated turning pile at full scale. Results illustrated that the reduction of amendment addition could result in low organic matter transformation (1.38% and 8.85% for the test group and the control group, respectively). Though low C/N ratio might slightly increase the ammonia emission (8.68% higher than the control group), it was helpful to reduce both GHG emission (1.70 g x kg(-1)) DC for the test group and 2.85 g x kg(-1) DC for the control group, respectively) and total nitrogen loss (16.1% and 21.8% for the test and control groups, respectively). Through applying an aertion strategy in which the airflow rate was lower in the beginning and higher in the end of sludge composting, a higher GHG emission and a lower ammonia emission were observed in the test group, e. g., 55.1% higher of GHG emission than the control, and 66.86 g x m(-2) and 72.04 g x m(-2) of ammonia emission in the test and the control, respectively. And a good conversation of total nitrogen thus occurred in the test as a result of such aeration strategy, with only 51.34% of TN loss as compared to the control.


Assuntos
Amônia/análise , Gases/análise , Eliminação de Resíduos/métodos , Esgotos/química , Nitrogênio/análise , Solo/química
7.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 44(5): 787-91, 2013 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-24325113

RESUMO

OBJECTIVE: To observe stress distributions around the acetabular prosthesis and the bones of a patient who underwent total hip arthroplasty (THA). METHODS: Finite element analysis (FEA) was performed with an osteoarthritis patient who underwent THA for her secondary hip high dislocations: Scenario A--deepened acetabulum at the true acetabulum with a small 44 mm cup; Scenario B--structural bone graft at lateral acetabular with a 48 mm cup; Scenario C--place tantalum metal acetabular reconstruction at the lateral acetabular with a 48 mm cup; Scenario D--the normal side of the hip. According to the Wasielewski methods, acetabular was divided into four zones, in the same way on the lining surface. Ten points were taken in each zone for measuring the Von Mises stress values. RESULTS: Scenario A generated significantly greater stress values in the bones in zone one than the other three scenarios. Significantly greater stress was also found in the inner surface of polyethylene over all of the four zones under scenario A compared with those of the scenario B and C, especially in zone one and two. The cup initial micro-mobility for scenario A was 49. 18 microm, 19 times of that of scenario B and 8 times of that of scenario C. CONCLUSION: (1) Deepened acetabulum with small cup can cause stress concentration in the acetabular bones and liner, leading to large cup initial micro-mobility. (2) Acetabular lateral structural bone grafting and placement of tantalum metal reconstruction have better biomechanical properties, which can enable the use of bigger cups.


Assuntos
Acetábulo/cirurgia , Artroplastia de Quadril , Análise de Elementos Finitos , Luxação do Quadril/cirurgia , Prótese de Quadril , Fenômenos Biomecânicos , Transplante Ósseo/métodos , Feminino , Luxação do Quadril/diagnóstico por imagem , Luxação do Quadril/etiologia , Luxação Congênita de Quadril/complicações , Luxação Congênita de Quadril/diagnóstico por imagem , Luxação Congênita de Quadril/cirurgia , Humanos , Imageamento Tridimensional , Pessoa de Meia-Idade , Radiografia , Estresse Mecânico , Tantálio
8.
J Ethnopharmacol ; 143(3): 896-904, 2012 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-22967667

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Ramulus Mori, the branch of Morus alba, is widely used in traditional Chinese medicine prescriptions to treat gout and hyperuricemia. AIM OF THIS STUDY: To evaluate the uricosuric and nephroprotective effects of ethanol extract of Ramulus Mori (ERM) and explore its possible mechanisms in hyperuricemic mice. MATERIALS AND METHODS: HPLC analysis was employed to determine the main constituents. Hyperuricemia was induced by potassium oxonate (250 mg/kg) in male mice. ERM (10, 20 and 40 mg/kg) was orally administered to hyperuricemic and normal mice for 7 days. Serum and urine levels of uric acid, creatinine and blood urea nitrogen (BUN) were measured. Simultaneously, renal mRNA and protein levels of mouse urate transporter 1 (mURAT1), glucose transporter 9 (mGLUT9), organic anion transporter 1 (mOAT1) and organic cation/carnitine transporters (mOCT1/2, mOCTN1/2) were analyzed by RT-PCR and Western blotting methods. RESULTS: ERM mainly contained mulberroside A, oxyresveratrol, 4-hydroxycinnamic acid, resveratrol, 7-hydroxycumarin and morin. ERM significantly reduced serum urate levels and increased 24h-urine urate excretion and fractional excretion of uric acid in hyperuricemic mice. It effectively restored oxonate-induced expression alteration of renal mURAT1, mGLUT9 and mOAT1, resulting in urate excretion enhancement. Moreover, ERM decreased serum creatinine and BUN levels and increased creatinine clearance, and up-regulated expression of mOCT1/2 and mOCTN1/2, contributing to kidney function improvement in this model. CONCLUSION: These results suggest that ERM exerts the uricosuric and nephroprotective actions by the regulation of these renal organic ion transporters in hyperuricemic mice, and provide scientific support for the empirical use of Ramulus Mori.


Assuntos
Hiperuricemia/tratamento farmacológico , Morus , Extratos Vegetais/uso terapêutico , Substâncias Protetoras/uso terapêutico , Animais , Nitrogênio da Ureia Sanguínea , Creatinina/sangue , Creatinina/urina , Etanol/química , Hiperuricemia/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Masculino , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Fitoterapia , Extratos Vegetais/análise , Substâncias Protetoras/análise , Solventes/química , Ácido Úrico/sangue , Ácido Úrico/urina
9.
Artigo em Chinês | MEDLINE | ID: mdl-18279593

RESUMO

OBJECTIVE: To investigate the effects of chronic ethanol ingestion and lipopolysaccharide (LPS) on airway epithelium barrier function and the expression of tight junction protein occludin and adherens junction protein E-cadherin. METHODS: Forty Sprague-Dawley (SD) rats were assigned to control, ethanol, LPS and ethanol+LPS groups. The bronchoalveolar epithelial permeability was assessed by the bronchoalveolar lavage fluid (BALF): serum fluorescein isothiocyanate (FITC)-dextran (FD(4)) fluorescence ratio. Protein localization and expression of occludin and E-cadherin in airway epithelium of rats lung were examined by immunofluorescence. The protein, messenger RNA expression of occludin and E-cadherin in the lung were examined by Western blotting and reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The bronchoalveolar epithelial permeability in the ethanol group and LPS group were approximately 2-fold higher than those in the control group (both P<0.05). The permeability in the ethanol+LPS group was increased further (P<0.01). Occludin and E-cadherin appeared as a continuous and uniform expression in the airway epithelium of control rats. In ethanol group and LPS group partial breakdown of membrane staining and decreased cytoplasm staining of occludin and E-cadherin were seen in the airway epithelium. In ethanol plus LPS group, there was breakdown of epithelial membrane and obvious disappearance of cytoplasm staining pattern of occludin and E-cadherin. Western blotting and RT-PCR showed that both in ethanol and LPS groups protein levels of occludin and E-cadherin were depressed in lung. Treatment with ethanol together with LPS further depressed the protein and mRNA levels of occludin and E-cadherin in lung. RT-PCR showed that messenger RNA levels of occludin and E-cadherin in ethanol group and LPS group were lower than those in the control group (both P< 0.05). Treatment with ethanol plus LPS had the greatest depressive effect on these messenger RNA levels (ethanol+LPS group vs. the other groups, all P<0.01). CONCLUSION: These data suggest that chronic ethanol ingestion impairs the airway epithelial barrier function through down-regulation the messenger RNA expression and disruption of membrane localization of occludin and E-cadherin. Those deterioration of occludin and E-cadherin predisposes to acute lung injury induced by LPS.


Assuntos
Lesão Pulmonar Aguda/metabolismo , Caderinas/metabolismo , Epitélio/metabolismo , Etanol/farmacologia , Proteínas de Membrana/metabolismo , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/fisiopatologia , Animais , Modelos Animais de Doenças , Endotoxinas/toxicidade , Epitélio/efeitos dos fármacos , Epitélio/fisiopatologia , Junções Intercelulares/metabolismo , Masculino , Ocludina , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Traqueia/efeitos dos fármacos , Traqueia/metabolismo , Traqueia/fisiopatologia
10.
Shock ; 28(2): 245-52, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17515855

RESUMO

Previous studies show that chronic alcohol abuse is an independent risk factor for acute lung injury (ALI) and impairs alveolar epithelial barrier function through glutathione depletion. However, the precise molecular structures that are damaged by chronic ethanol ingestion have not been identified. To test whether chronic ethanol ingestion impairs the alveolar epithelium barrier by tight junction protein deterioration and predisposes to ALI, this study determined the alterations in tight junction proteins occludin, zonula occludens (ZO)-1, and adherens junction protein E-cadherin in alveolar epithelium and observed the protective effect of glutamine (Gln) supplementation. Sixty Sprague-Dawley rats were assigned to control, ethanol (6 weeks' ethanol feeding), lipopolysaccharide ([LPS] 2 mg/kg, i.v.), ethanol plus LPS, ethanol plus Gln (0.3 g/kg, gavage daily), and ethanol plus Gln plus LPS groups. Treatment with both ethanol and LPS significantly increased bronchoalveolar epithelial permeability, and treatment with ethanol plus LPS further increased the permeability. Using immunofluorescence, immunoblotting, and reverse transcriptase-polymerase chain reaction, this study shows that treatment with both ethanol and LPS induced partial breakdown of membrane staining and decreased cytoplasm staining in alveolar epithelium and decreased the messenger RNA and protein expression of those molecules in alveolar epithelial cells. Treatment with ethanol plus LPS caused further deterioration. Moreover, Gln supplementation markedly attenuated the enhanced bronchoalveolar epithelial permeability and decreased messenger RNA and protein expression of those molecules induced by ethanol and ethanol plus LPS. These data suggest that chronic ethanol ingestion impairs the alveolar epithelial barrier function via occludin, ZO-1, and E-cadherin deterioration, and predisposes to ALI. Glutamine supplementation has protective effect.


Assuntos
Etanol/administração & dosagem , Proteínas de Membrana/metabolismo , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/metabolismo , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo , Animais , Células Cultivadas , Epitélio/efeitos dos fármacos , Epitélio/metabolismo , Masculino , Concentração Osmolar , Ratos , Ratos Sprague-Dawley
11.
J Lipid Res ; 48(5): 1108-21, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17277355

RESUMO

Prior studies have suggested that FAs liberated in the small intestine from ingested 1,3-diacylglycerol (DAG) are inefficiently incorporated into triglyceride (TG) in enterocytes, with less chylomicron TG entering the circulation postprandially. We found less TG, but more monacylglyerol and DAG, with similar total acylglycerol in newly secreted chylomicrons after oral DAG or triacylglycerol (TAG). However, clearance of DAG-chylomicrons was more rapid than that of TAG-chylomicrons; this was associated with more efficient in vitro LPL-mediated lipolysis of DAG-derived chylomicrons. Intravenously infused DAG was also cleared faster than TAG in normal mice, via both LPL-mediated lipolysis and apolipoprotein E (apoE)-dependent hepatic uptake. Infusions of TAG, but not DAG, increased plasma TG levels. Greater delivery of DAG-derived FA to the liver during infusion of DAG led to greater TG secretion versus TAG; this allowed the maintenance of similar hepatic TG levels after DAG and TAG infusions. Of note, apoB secretion was similar after DAG versus TAG, indicating the assembly of larger very low density lipoproteins after DAG. In conclusion, reduced plasma TG levels, after oral or intravenous DAG, result from more efficient clearance of DAG by both LPL lipolysis and apoE-mediated hepatic endocytosis. DAG emulsions may by useful for intravenous nutrition in people with preexisting hypertriglyceridemia.


Assuntos
Apolipoproteínas B/metabolismo , Diglicerídeos/farmacologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Óleos/farmacologia , Triglicerídeos/farmacologia , Administração Oral , Animais , Quilomícrons/isolamento & purificação , Quilomícrons/metabolismo , Diglicerídeos/metabolismo , Emulsões , Glicerídeos/metabolismo , Hidrólise , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Óleos/metabolismo , Oxirredução , Tamanho da Partícula , Polietilenoglicóis , RNA Mensageiro/genética , Triglicerídeos/metabolismo
12.
J Biol Chem ; 281(49): 37603-15, 2006 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-16971390

RESUMO

Insulin-resistant apoB/BATless mice have hypertriglyceridemia because of increased assembly and secretion of very low density apolipoprotein B (apoB) and triglycerides compared with mice expressing only apoB (Siri, P., Candela, N., Ko, C., Zhang, Y., Eusufzai, S., Ginsberg, H. N., and Huang, L. S. (2001) J. Biol. Chem. 276, 46064-46072). Despite increased very low density lipoprotein secretion, apoB/BATless mice have fatty livers. We found that hepatic mRNA levels of key lipogenic enzymes, acetyl-CoA carboxylase, fatty-acid synthase, and stearoyl-CoA desaturase-1 were increased in apoB/BATless mice compared with levels in apoB mice, suggesting increased lipogenesis in apoB/BATless mice. This was confirmed by determining incorporation of tritiated water into fatty acids. Neither the hepatic mRNA of the lipogenic transcription factor, SREBP-1c (sterol-response element-binding protein 1c), nor the nuclear levels of the mature form of SREBP-1 protein were elevated in apoB/BATless mice. By contrast, hepatic levels of peroxisomal proliferator-activated receptor 2 (PPARgamma2) mRNA and protein were specifically increased in apoB/BATless mice, as were hepatic mRNA levels of two targets of PPARgamma, CD36 and aP2. Treatment of apoB/BATless mice for 4 weeks with intraperitoneal injections of a PPARgamma antisense oligonucleotide resulted in dramatic reductions of both PPARgamma1 and PPARgamma2 mRNA, PPARgamma2 protein, and mRNA levels of fatty-acid synthase and acetyl-CoA carboxylase. These changes were associated with decreased hepatic de novo lipogenesis and hepatic triglyceride concentrations. We conclude that hepatic steatosis in apoB/BATless mice is associated with elevated rates of hepatic lipogenesis that are linked directly to increased hepatic expression of PPARgamma2. The mechanism whereby hepatic Ppargamma2 gene expression is increased and how PPARgamma2 stimulates lipogenesis is under investigation.


Assuntos
Dislipidemias/metabolismo , Fígado Gorduroso/metabolismo , Resistência à Insulina/fisiologia , Fígado/metabolismo , Obesidade/metabolismo , PPAR gama/genética , PPAR gama/metabolismo , Tecido Adiposo Marrom/metabolismo , Animais , Apolipoproteínas B/genética , Sequência de Bases , Primers do DNA/genética , Modelos Animais de Doenças , Dislipidemias/genética , Fígado Gorduroso/genética , Feminino , Expressão Gênica , Humanos , Resistência à Insulina/genética , Lipogênese/genética , Lipogênese/fisiologia , Masculino , Camundongos , Camundongos Congênicos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Obesidade/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
14.
Arch Med Res ; 36(3): 232-40, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15925013

RESUMO

Increased plasma levels of triglycerides (TG) in very low density lipoproteins (VLDL) are not only common characteristics of the dyslipidemia associated with insulin resistance and type 2 diabetes mellitus (T2DM) but are the central pathophysiologic feature of the abnormal lipid profile. Overproduction of VLDL leads to increased plasma levels of TG which, via an exchange process mediated by cholesterol ester transfer protein (CETP), results in low levels of high density lipoprotein (HDL) cholesterol and apolipoprotein A-I, and the generation of small, dense, cholesterol ester depleted low density lipoproteins (LDL). Increased assembly and secretion of VLDL by the liver results from the complex, post-transcriptional regulation of apolipoprotein B (apoB) metabolism in the liver. In the presence of low levels of hepatic TG and cholesterol, much of the constitutively synthesized apoB is degraded by both proteasomal and non-proteasomal pathways. When excess TG, and to a lesser extent, cholesterol, are present, and in the presence of active microsomal triglycerides transfer protein, apoB is targeted for secretion. The major sources of TG in the liver: uptake of fatty acids (FA) released by lipolysis of adipose tissue TG, uptake of TGFA in VLDL and chylomicrons remnants, and hepatic de novo lipogenesis (the synthesis of FA from glucose) are all abnormally increased in insulin resistance. Treatment of the dyslipidemia in insulin resistant individuals and patients with T2DM has been successful in reducing cardiovascular disease; LDL cholesterol, TG, and HDL cholesterol are all appropriate targets for therapy when diet, exercise, and weight loss do not achieve goals.


Assuntos
Diabetes Mellitus Tipo 2/sangue , Resistência à Insulina , Triglicerídeos/sangue , Tecido Adiposo/metabolismo , Animais , Apolipoproteína A-I/metabolismo , Apolipoproteínas B/metabolismo , Colesterol/metabolismo , Quilomícrons/metabolismo , Ácidos Graxos/metabolismo , Humanos , Metabolismo dos Lipídeos , Lipoproteínas/metabolismo , Lipoproteínas HDL/metabolismo , Lipoproteínas VLDL/química , Fígado/metabolismo , Modelos Biológicos
15.
J Clin Invest ; 113(9): 1277-87, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15124019

RESUMO

How omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) lower plasma lipid levels is incompletely understood. We previously showed that marine omega-3 PUFAs (docosahexaenoic acid [DHA] and eicosapentaenoic acid) stimulate a novel pathway, post-ER presecretory proteolysis (PERPP), that degrades apolipoprotein B100 (ApoB100), thereby reducing lipoprotein secretion from liver cells. To identify signals stimulating PERPP, we examined known actions of omega-3 PUFA. In rat hepatoma or primary rodent hepatocytes incubated with omega-3 PUFA, cotreatment with the iron chelator desferrioxamine, an inhibitor of iron-dependent lipid peroxidation, or vitamin E, a lipid antioxidant, suppressed increases in thiobarbituric acid-reactive substances (TBARSs; a measure of lipid peroxidation products) and restored ApoB100 recovery and VLDL secretion. Moreover, omega-6 and nonmarine omega-3 PUFA, also prone to peroxidation, increased ApoB100 degradation via intracellular induction of TBARSs. Even without added fatty acids, degradation of ApoB100 in primary hepatocytes was blocked by desferrioxamine or antioxidant cotreatment. To extend these results in vivo, mice were infused with DHA, which increased hepatic TBARSs and reduced VLDL-ApoB100 secretion. These results establish a novel link between lipid peroxidation and oxidant stress with ApoB100 degradation via PERPP, and may be relevant to the hypolipidemic actions of dietary PUFAs, the basal regulation of ApoB100 secretion, and hyperlipidemias arising from ApoB100 overproduction.


Assuntos
Apolipoproteínas B/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Lipoproteínas VLDL/biossíntese , Fígado/metabolismo , Estresse Oxidativo , Animais , Antioxidantes/metabolismo , Linhagem Celular Tumoral , Células Cultivadas , Quelantes/farmacologia , Desferroxamina/farmacologia , Gorduras na Dieta/farmacologia , Ácidos Docosa-Hexaenoicos/farmacologia , Retículo Endoplasmático/metabolismo , Ácidos Graxos Ômega-3/metabolismo , Óleos de Peixe/farmacologia , Hepatócitos/citologia , Fígado/citologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Processamento de Proteína Pós-Traducional , Ratos , Fatores de Tempo , Vitamina E/farmacologia
16.
J Biol Chem ; 279(18): 19362-74, 2004 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-14970200

RESUMO

The in vivo effects of increased delivery of fatty acids (FA) to the liver are poorly defined. Therefore, we compared the effects of infusing either 6 mM oleic acid (OA) bound to albumin, 0.5-20% Intralipid, or saline for 3 or 6 h into male C57BL/6J mice. Infusions were followed by studies of triglyceride (TG) and apoB secretion. Although plasma FA levels increased similarly after either 20% Intralipid or 6 mM OA, TG secretion increased only after infusion of 4-20% Intralipid; TG secretion was unchanged by 6 mM OA. By contrast, 6-h infusions of either 6 mM OA or 4-20% Intralipid increased apoB secretion. 6 mM OA and 20% Intralipid each increased secretion of apoB from primary hepatocytes ex vivo. Importantly, 0.5-2% Intralipid, which delivered more FA to the liver than 6 mM OA, did not stimulate apoB secretion. Hepatic apoB mRNA levels were unaffected by either 6 mM OA or 20% Intralipid, but microsomal triglyceride transfer protein mRNA was significantly lower after 6-h infusions with 6 mM OA versus either saline or 20% Intralipid. Lower microsomal triglyceride transfer protein mRNA levels were associated with reduced hepatic TG mass after 6-h infusions of 6 mM OA. We conclude that 1) increased FA delivery to the liver in vivo increases secretion of apoB-lipoproteins via post-transcriptional mechanisms, 2) OA-induced apoB-lipoprotein secretion occurred at least in part via mechanisms other than by providing substrate for TG synthesis, and 3) the route of delivery of FA is important for its effects on apoB secretion.


Assuntos
Apolipoproteínas B/metabolismo , Ácidos Graxos/farmacologia , Fígado/metabolismo , Animais , Apolipoproteínas B/genética , Proteínas de Transporte/genética , Ácidos Graxos/administração & dosagem , Lipoproteínas/metabolismo , Fígado/citologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microssomos Hepáticos/química , Ácidos Oleicos/administração & dosagem , Ácidos Oleicos/farmacologia , RNA Mensageiro/análise , RNA Mensageiro/efeitos dos fármacos , Triglicerídeos/metabolismo
18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 22(1): 89-91, 2002 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-12940037

RESUMO

A direct method was reported for the determination of total sulfur in coal by inductively coupled plasma atomic emission spectrometry (ICP-AES). The dissolution conditions of coal samples as well as interference conditions of hydrochloric acid and matrix were studied. The recommended method not only proved to be simple and rapid than traditional gravimetric method but show satisfying precision and accuracy as well. The results of samples are as same as gravimetry. The recoveries are more than 96%, and the relative standard deviation of six samples are less than 3%.


Assuntos
Carvão Mineral/análise , Enxofre/análise , Poluentes Atmosféricos/análise , Espectrometria de Massas/métodos , Espectrofotometria Atômica/métodos , Dióxido de Enxofre/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...