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1.
Cardiol Young ; 34(3): 659-666, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37724575

RESUMO

BACKGROUND: This meta-analysis aimed to consolidate existing data from randomised controlled trials on hypoplastic left heart syndrome. METHODS: Hypoplastic left heart syndrome specific randomised controlled trials published between January 2005 and September 2021 in MEDLINE, EMBASE, and Cochrane databases were included. Regardless of clinical outcomes, we included all randomised controlled trials about hypoplastic left heart syndrome and categorised them according to their results. Two reviewers independently assessed for eligibility, relevance, and data extraction. The primary outcome was mortality after Norwood surgery. Study quality and heterogeneity were assessed. A random-effects model was used for analysis. RESULTS: Of the 33 included randomised controlled trials, 21 compared right ventricle-to-pulmonary artery shunt and modified Blalock-Taussig-Thomas shunt during the Norwood procedure, and 12 regarded medication, surgical strategy, cardiopulmonary bypass tactics, and ICU management. Survival rates up to 1 year were superior in the right ventricle-to-pulmonary artery shunt group; this difference began to disappear at 3 years and remained unchanged until 6 years. The right ventricle-to-pulmonary artery shunt group had a significantly higher reintervention rate from the interstage to the 6-year follow-up period. Right ventricular function was better in the modified Blalock-Taussig-Thomas shunt group 1-3 years after the Norwood procedure, but its superiority diminished in the 6-year follow-up. Randomised controlled trials regarding medical treatment, surgical strategy during cardiopulmonary bypass, and ICU management yielded insignificant results. CONCLUSIONS: Although right ventricle-to-pulmonary artery shunt appeared to be superior in the early period, the two shunts applied during the Norwood procedure demonstrated comparable long-term prognosis despite high reintervention rates in right ventricle-to-pulmonary artery shunt due to pulmonary artery stenosis. For medical/perioperative management of hypoplastic left heart syndrome, further randomised controlled trials are needed to deliver specific evidence-based recommendations.


Assuntos
Procedimento de Blalock-Taussig , Síndrome do Coração Esquerdo Hipoplásico , Humanos , Síndrome do Coração Esquerdo Hipoplásico/cirurgia , Ponte Cardiopulmonar , Bases de Dados Factuais , Ventrículos do Coração/cirurgia , Ensaios Clínicos Controlados Aleatórios como Assunto
2.
Int J Tuberc Lung Dis ; 24(4): 390-395, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32317062

RESUMO

SETTING: In Korea, the price of a pack of cigarettes increased 80% from US$2.2 to US$4 in 2015. The smoking rate decreased in 2015. However, it rebounded in the following year.OBJECTIVE: To evaluate the characteristics associated with this rebound in smoking rate following the price increase.DESIGN: We analysed the KNHANES (Korean National Health and Nutrition Examination Survey) data of 44 015 participants to evaluate current smoking rate and the proportion of smokers planning to quit within 6 months from 2010 to 2016. We also performed focused analysis of 18 303 participants between 2014 and 2016 KNHANES to determine the current smoking rate according to their demographic and socio-economic characteristics.RESULTS: Individuals who were older, female, unemployed, had a low household income or a shorter total smoking period, or smoked less per day were more likely to stop or reduce smoking after the price increase. The current smoking rate increased to 18.8% in 2016 from 17.7% in 2015; this difference was significant in men, those in the lower-middle quartile of household income, those with a middle-school or college education, and those who were employed.CONCLUSION: The rebound in smoking after the price increase was significantly related to the individual's sex, income, education and employment status.


Assuntos
Abandono do Hábito de Fumar , Produtos do Tabaco , Comércio , Feminino , Humanos , Masculino , Inquéritos Nutricionais , República da Coreia/epidemiologia , Fumar/epidemiologia , Nicotiana
3.
Allergy ; 73(9): 1833-1841, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29517808

RESUMO

BACKGROUND: Few studies have investigated the incidence of anaphylaxis induced by individual or structurally similar cephalosporins. The aims of the study were to assess the incidence of cephalosporin-induced anaphylaxis and evaluate the clinical efficacy of screening skin tests. METHODS: In this retrospective cohort study, we obtained information on total cephalosporin use and cephalosporin-induced anaphylaxis in intravenous cephalosporin recipients in 12 general hospitals between 2013 and 2015. Cephalosporins were divided into 4 groups according to similar side-chain structures. The incidence of cephalosporin-induced anaphylaxis was assessed for each cephalosporin, cephalosporin generation, and side-chain group. To verify the efficacy of screening intradermal tests (IDT) with cephalosporin, the 12 hospitals were assigned to the intervention or control group depending on whether they performed screening IDT before the administration of cephalosporins. RESULTS: We identified 76 cases of cephalosporin-induced anaphylaxis with 1 123 345 exposures to intravenous cephalosporins (6.8 per 100 000 exposures), and the incidence of fatal anaphylaxis by cephalosporin was 0.1 cases per 100 000 exposures. The highest incidences of anaphylaxis occurred in the ceftizoxime (13.0 cases per 100 000 exposures) and side-chain group 1 (cefepime, cefotaxime, ceftizoxime, ceftriaxone, and cefuroxime; 9.3 per 100 000). There was no case of anaphylaxis induced by cefoxitin, cefmetazole, cefminox, and cefotiam. The clinical effectiveness of routine screening IDT was not significant (P = .06). CONCLUSIONS: The incidence of cephalosporin-induced anaphylaxis differed according to individual drugs and side-chain structure. Screening IDT showed no clinical efficacy at a population level.


Assuntos
Anafilaxia/epidemiologia , Anafilaxia/etiologia , Antibacterianos/efeitos adversos , Cefalosporinas/efeitos adversos , Hipersensibilidade a Drogas/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anafilaxia/diagnóstico , Anafilaxia/mortalidade , Antibacterianos/administração & dosagem , Antibacterianos/química , Cefalosporinas/administração & dosagem , Cefalosporinas/química , Hipersensibilidade a Drogas/diagnóstico , Feminino , Humanos , Incidência , Testes Intradérmicos/métodos , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Vigilância em Saúde Pública , Estudos Retrospectivos
4.
Transplant Proc ; 44(3): 765-8, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22483490

RESUMO

PURPOSE: To assess the incidence and management of postoperative abdominal bleeding after orthotopic liver transplantation (OLT) and to identify risk factors for abdominal bleeding. METHODS: We retrospectively reviewed the medical records of 1039 patients who underwent OLT at our institution from January 2008 to December 2010 seeking to identify subjects with posttransplantation abdominal bleeding, defined as any hemorrhage requiring radiologic intervention or laparotomy within the first month. RESULTS: Among the 1039 patients, 94 (9%) showed abdominal bleeding, occurring at a mean of 6.1 days (range, day 1 to 21 days). Active bleeding was controlled by endovascular interventional techniques (n = 37; 39%), by surgical ligation or vascular reconstruction (n = 43; 46%), or by sequential combinations of endovascular intervention and surgery (n = 14; 15%). The most frequent bleeding sites for radiologic intervention were the right inferior phrenic artery (n = 14), right and left epigastric arteries (n = 7), intercostal artery (n = 5) and right renal capsular artery (n = 4). The most frequent bleeding sites requiring laparotomy were the hepatic artery (n = 9), diaphragm (n = 8), inferior vena cava (n = 5), abdominal drain insertion site (n = 4), portal vein anastomosis site (n = 4), abdominal wall (n = 3), liver graft cut surface (n = 3), hilar plate (n = 3), and greater omentum (n = 3). Bleeding episodes were associated with greater patient age and increased intraoperative blood loss. CONCLUSIONS: The risk of bleeding from coagulopathy and iatrogenic injury is high during the early posttransplantation period. This risk of bleeding can be minimized by meticulous surgical dissection and bleeding control.


Assuntos
Abdome , Transplante de Fígado , Hemorragia Pós-Operatória/terapia , Adulto , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Hemorragia Pós-Operatória/complicações
5.
Int J Obes (Lond) ; 35(8): 1019-30, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21157426

RESUMO

INTRODUCTION: Globally, non-alcoholic fatty liver disease (NAFLD) continues to rise and isoflavones exert antisteatotic effects by the regulation of hepatic lipogenesis/insulin resistance or adiposity/a variety of adipocytokines are related to hepatic steatosis. However, there is very little information regarding the potential effects of daidzein, the secondary abundant isoflavone, on NAFLD. Here, we have assessed the hepatic global transcription profiles, adipocytokines and adiposity in mice with high fat-induced NAFLD and their alteration by daidzein supplementation. METHODS: C57BL/6J mice were fed with normal fat (16% fat of total energy), high fat (HF; 36% fat of total energy) and HF supplemented with daidzein (0.1, 0.5, 1 and 2 g per kg diet) for 12 weeks. RESULTS: Daidzein supplementation (≥ 0.5 g per kg diet) reduced hepatic lipid concentrations and alleviated hepatic steatosis. The hepatic microarray showed that daidzein supplementation (1 g per kg diet) downregulated carbohydrate responsive element binding protein, a determinant of de novo lipogenesis, its upstream gene liver X receptor ß and its target genes encoding for lipogenic enzymes, thereby preventing hepatic steatosis and insulin resistance. These results were confirmed by lower insulin and blood glucose levels as well as homeostasis model assessment insulin resistance scores. In addition, daidzein supplementation inhibited adiposity by the upregulation of genes involved in fatty acid ß-oxidation and the antiadipogeneis, and moreover augmented antisteatohepatitic leptin and adiponectin mRNA levels, whereas it reduced the mRNA or concentration of steatotic tumor necrosis factor α and ghrelin. CONCLUSIONS: These findings show that daidzein might alleviate NAFLD through the direct regulation of hepatic de novo lipogenesis and insulin signaling, and the indirect control of adiposity and adipocytokines by the alteration of adipocyte metabolism.


Assuntos
Adipócitos/efeitos dos fármacos , Adipocinas/metabolismo , Tecido Adiposo/efeitos dos fármacos , Fígado Gorduroso/prevenção & controle , Isoflavonas/farmacologia , Lipogênese/efeitos dos fármacos , Fitoestrógenos/farmacologia , Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Animais , Peso Corporal , Dieta , Fígado Gorduroso/tratamento farmacológico , Fígado Gorduroso/metabolismo , Perfilação da Expressão Gênica , Insulina/metabolismo , Resistência à Insulina , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica , Reação em Cadeia da Polimerase Via Transcriptase Reversa
6.
Cell Prolif ; 43(6): 594-605, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21039998

RESUMO

OBJECTIVES: One aspect of the effects of isoflavones against fat deposition might be at least associated with the mechanism by which Wnt/ß-catenin signalling inhibits adipocyte differentiation. However, it remains completely unknown as to whether isoflavones might influence Wnt signalling during commitment of pluripotent mesenchymal stem cells (MSCs) to adipose lineages. In the present study, we have investigated the mechanisms underlying effects of genistein and daidzein, the major soy isoflavones, on anti-adipogenic Wnt/ß-catenin signalling. MATERIALS AND METHODS: Adipose tissue-derived (AD) MSCs were exposed continuously to genistein and daidzein (0.01-100 µm) during adipogenic differentiation (21 days). An oestrogen antagonist, ICI 182,780, was used to determine whether or not the isoflavones activated Wnt signalling via oestrogen receptors (ERs). RESULTS: Genistein and daidzein suppressed adipogenic differentiation of AD-MSCs in a dose-dependent manner and inhibited expression of adipogenic markers, PPARγ, SREBP-1c and Glut 4, from mid-phase differentiation. Microarrays showed that anti-adipogenic effects of genistein were principally attributable to activation of Wnt signalling via ERs-dependent pathway, such as Erk/JNK signalling and LEF/TCF4 co-activators. These findings were supported by evidence that the effects of genistein were offset by ICI182,780. Unlike genistein, daidzein inhibited adipogenesis through stimulation of lipolysis, with for example, PKA-mediated hormone sensitive lipase. This is consistent with the increase in glycerol released from AD-MSCs. In conclusion, understanding that different sets of mechanisms of the two isoflavones on adipogenesis will help the design of novel strategies to prevent observed current epidemic levels of obesity, using isoflavones.


Assuntos
Tecido Adiposo/citologia , Genisteína/farmacologia , Isoflavonas/farmacologia , Lipólise/efeitos dos fármacos , Células-Tronco Mesenquimais/efeitos dos fármacos , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Adipogenia/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Transdução de Sinais/efeitos dos fármacos
7.
Cell Prolif ; 43(1): 19-28, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20070733

RESUMO

OBJECTIVES: In recent years, obesity has become a global epidemic, highlighting the necessity for basic research into mechanisms underlying growth of adipose tissue and differentiation of stem cells into adipocytes, in humans. For better understanding of cell signalling in adipogenesis, the role of DNER (delta/Notch-like EGF-related receptor) in adipogenic differentiation of human adipose tissue-derived mesenchymal stem cells (hAMSC) was investigated. MATERIALS AND METHODS: To assess the role of DNER in hAMSC adipogenesis, hAMSCs were transfected with DNER small interfering RNA (siDNER). Real-time quantitative reverse transcriptase polymerase chain reactions to assess expression levels of adipogenesis-related genes regulated by siDNER, cell cycle and immunoblot analyses were performed. RESULTS: First, it was determined that DNER mRNA was profoundly expressed in hAMSCs and reduced during adipogenic differentiation. Knockdown of DNER altered cell morphology, inhibited proliferation and increased frequency and efficiency of adipogenesis in hAMSC. Expression of CCAAT/enhancer-binding protein delta increased and proportion of cells in S phase decreased by knockdown of DNER, using specific siRNA. Moreover, adipocyte-specific genes including peroxisome proliferator-activated receptor gamma, fatty acid binding protein 4 and perilipin were up-regulated in siDNER compared to the siControl group during adipogenesis in hAMSC. CONCLUSIONS: These results indicate that DNER knockdown in hAMSC accelerated onset of adipogenic differentiation by bypassing mitotic clonal expansion during the early stages of adipogenesis.


Assuntos
Adipogenia , Tecido Adiposo/citologia , Células-Tronco Mesenquimais/citologia , Proteínas do Tecido Nervoso/metabolismo , Receptores de Superfície Celular/metabolismo , Tecido Adiposo/metabolismo , Proteína delta de Ligação ao Facilitador CCAAT/genética , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Proteínas de Ligação a Ácido Graxo/genética , Proteínas de Ligação a Ácido Graxo/metabolismo , Técnicas de Silenciamento de Genes , Humanos , Células-Tronco Mesenquimais/metabolismo , Mitomicina/farmacologia , Proteínas do Tecido Nervoso/genética , Inibidores da Síntese de Ácido Nucleico/farmacologia , PPAR gama/genética , PPAR gama/metabolismo , RNA Interferente Pequeno/metabolismo , Receptores de Superfície Celular/genética , Fase S , Regulação para Cima
8.
Cell Prolif ; 42(6): 711-20, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19689470

RESUMO

OBJECTIVES: Histone deacetylase (HDAC) is an important therapeutic target in cancer. Two of the main anticancer mechanisms of HDAC inhibitors are induction of terminal differentiation and inhibition of cell proliferation. To investigate the role of HDAC in maintenance of self-renewal and cell proliferation, we treated mesenchymal stem cells (MSCs) that originated from adipose tissue or umbilical cord blood with valproic acid (VPA) and sodium butyrate (NaBu). MATERIALS AND METHODS: Human MSCs were isolated from mammary fat tissue and cord blood. We performed MTT assay and flow cytometry-based cell cycle analysis to assess self-renewal of MSCs. In vitro differentiation assays into osteogenic, adipogenic, neurogenic and chondrogenic lineages were conducted to investigate MSC multipotency. Immunocytochemistry, Western blot and reverse transcription-polymerase chain reaction were used to interrogate molecular pathways. RESULTS: VPA and NaBu flattened the morphology of MSCs and inhibited their growth. VPA and NaBu activated the transcription of p21(CIP1/WAF1) by increasing the acetylation of histone H3 and H4 and eventually blocked the cell cycle at G2/M phase. The expression level of p16(INK4A), a cdk inhibitor that is closely related to cellular senescence, was not changed by HDAC inhibitor treatment. We performed controlled differentiation into bone, fat, cartilage and nervous tissue to elucidate the role of HDAC in the pluripotency of MSC to differentiate into functional tissues. VPA and NaBu decreased the efficiency of adipogenic, chondrogenic, and neurogenic differentiation as visualized by specific staining and reverse transcription-polymerase chain reaction. In contrast, osteogenic differentiation was elevated by HDAC inhibitor treatment. CONCLUSION: HDAC activity is essential for maintaining the self-renewal and pluripotency of MSCs.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Linhagem da Célula , Proliferação de Células/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Inibidores de Histona Desacetilases , Células-Tronco Mesenquimais/efeitos dos fármacos , Western Blotting , Ciclo Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Humanos , Imuno-Histoquímica , Células-Tronco Mesenquimais/citologia , Osteogênese , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para Cima
9.
Cell Prolif ; 41(6): 859-874, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19040566

RESUMO

OBJECTIVES: The canonical Wnt signalling pathway performs an important function in the control of adipogenesis. However, the mechanisms and mediators underlying these interactions have yet to be defined in detail. Thus, this study was performed in order to elucidate the roles of the Wnt family during adipogenic differentiation of human adipose tissue-derived mesenchymal stem cells (hAMSCs). MATERIALS AND METHODS: We assessed several members of the Frizzled (FZD) family, the receptors of Wnts, inhibitors including the secreted frizzled-related protein (sFRP) family and Dickkopfs (Dkks), and the downstream factor, beta-catenin. Expressional levels of adipogenic markers regulated by the small interfering RNA of Dkk1 (siDkk1) and sFRP4 (sisFRP4) were assessed using real-time quantitative PCR and Western blot analysis. RESULTS: The mRNA level of Dkk1 was expressed abundantly in the early stages of adipogenesis and decreased rapidly during the late stages of adipogenesis. However, sFRP4 mRNA was up-regulated gradually during adipogenic differentiation in hAMSCs. Expression of FZD1, FZD7 and beta-catenin were reduced during adipogenic differentiation. Transfection of hAMSCs with siDkk1 or sisFRP4 partially inhibited differentiation of hAMSCs into adipocytes and restored levels of beta-catenin. CONCLUSIONS: We determined that Dkk1 was up-regulated transiently in the early stages of adipogenesis, and that sFRP4 levels increased gradually during adipogeneis via inhibition of Wnt signalling. Collectively, these results show that Dkk1 and sFRP4 perform an important function in adipogenesis in hAMSCs.


Assuntos
Adipogenia , Tecido Adiposo/citologia , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Células-Tronco Mesenquimais/citologia , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Wnt/antagonistas & inibidores , Tecido Adiposo/metabolismo , Separação Celular , Células Cultivadas , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Células-Tronco Mesenquimais/metabolismo , Proteínas Proto-Oncogênicas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Superfície Celular/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais
10.
Clin Exp Allergy ; 32(12): 1706-12, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12653160

RESUMO

BACKGROUND: Although asthma is a common cause of morbidity in adults, relatively few objectively measured population studies of asthma prevalence in adult populations have been conducted. OBJECTIVE: To evaluate the prevalence of asthma, based on both a questionnaire and methacholine bronchial provocation test, and to determine the risk factors of asthma prevalence in an adult population. METHODS: A total of 2,467 adults, who were randomly selected from metropolitan urban, non-metropolitan urban and rural areas, responded to the modified ISAAC questionnaire, and underwent methacholine bronchial provocation tests and skin prick tests to locally common aeroallergens. RESULTS: The prevalence of current asthma based on the questionnaire and the methacholine challenge was 2.0% in adults younger than 40, 3.8% in 40- to 54-year-olds, 7.7% in 55- to 64-year-olds and 12.7% in those aged 65 or higher. For subjects of 55-64 years, active smoking was found to be significantly related with the prevalence of current asthma and bronchial hyper-responsiveness, although smoking was positively associated with percentage predictive value of forced expiratory volume of 1 s (FEV1). CONCLUSION: The prevalence of current asthma is common among the elderly, and active smoking may play an important role in the development of asthma and bronchial hyper-responsiveness among the elderly.


Assuntos
Asma/epidemiologia , Asma/etiologia , Fumar/efeitos adversos , Adulto , Distribuição por Idade , Idoso , Asma/fisiopatologia , Testes de Provocação Brônquica , Broncoconstritores , Feminino , Humanos , Hipersensibilidade Imediata/epidemiologia , Coreia (Geográfico)/epidemiologia , Modelos Logísticos , Pulmão/fisiopatologia , Masculino , Cloreto de Metacolina , Pessoa de Meia-Idade , Prevalência , Saúde da População Rural , Testes Cutâneos , Fumar/epidemiologia , Saúde da População Urbana
11.
Eur J Biochem ; 268(3): 582-91, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11168397

RESUMO

Melanocortins are known to be involved in the regulation of feeding behavior. These hormones mediate their effects through G-protein-coupled receptors by stimulating adenylate cyclase. In this study we describe the functional response of melanocortin 4 receptor (MC4R) and melanocortin 3 receptor (MC3R) in HEK 293T cells, by using a luciferase reporter gene under the transcriptional control of a cAMP-responsive element (CRE) as a monitor of intracellular cAMP levels and cAMP-regulated gene expression. We were able to show that MC4R and MC3R expressed in the human cell line HEK 293T stimulate transcription induced by stimulation with different analogs of alpha-melanocyte-stimulating hormone (alpha-MSH) at different levels. In our assay of CRE-mediated gene transcription activity, alpha-MSH-ND was the most efficient alpha-MSH analog for MC4R whereas NDP-MSH was the most efficient for MC3R. Changing the His6 residue of alpha-MSH-ND to Gln or Lys markedly decreased CRE-mediated luciferase activity for MC3R compared with MC4R. On analysis by modeling the receptor-ligand complex by NMR, [Gln6]alpha-MSH-ND and [Lys6]alpha-MSH-ND showed different conformational interactions between MC3R and MC4R. Furthermore, the maximum coupling efficiency of MC4R and MC3R to G proteins was different; MC4R showed only 30-50% of the maximum activity induced by MC3R. In total, our results suggest that a differential receptor-ligand interaction is involved and that the relative interactions of MC3R and MC4R with G protein are possibly quantitatively and qualitatively different.


Assuntos
Hormônio Adrenocorticotrópico/metabolismo , AMP Cíclico/metabolismo , Regulação da Expressão Gênica , Receptores da Corticotropina/metabolismo , Transcrição Gênica , Hormônio Adrenocorticotrópico/análogos & derivados , Hormônio Adrenocorticotrópico/química , Aminoácidos/química , Animais , Sítios de Ligação , Northern Blotting , Células CHO , Linhagem Celular , Cricetinae , Genes Reporter , Humanos , Ligantes , Luciferases/metabolismo , Espectroscopia de Ressonância Magnética , Modelos Químicos , Modelos Moleculares , Mutação , Ligação Proteica , Receptor Tipo 3 de Melanocortina , Receptor Tipo 4 de Melanocortina , Receptores da Corticotropina/química , Elementos de Resposta , Fatores de Tempo , alfa-MSH/química , alfa-MSH/metabolismo
12.
Biochem Biophys Res Commun ; 276(3): 1278-85, 2000 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-11027623

RESUMO

A designed peptide, PGAa showed an excellent antifungal activity as well as an efficient bactericidal activity toward gram-positive, especially in the pathogenic yeast Candida albicans 28838. The solution structures of PGAa have been determined both in 40% TFE/water solution and DPC micelle by CD and NMR spectroscopy. Based on NOEs, vicinal coupling constants, backbone amide exchange rates, and chemical shift indices, PGAa formed a long amphipathic alpha-helical conformation in both TFE and DPC micelle environments, spanning the residues Ile(2)-Ala(19) in TFE and Lys(5)-Ala(19) in DPC micelle, respectively. Solution structures suggested that the hydrophobic residues would interact with the fatty acyl chains of the lipid bilayer, while the positively charged side-chains exposed to aqueous environments. Therefore, we conclude that the alpha-helical structure as well as the highly amphiphatic nature of PGAa peptide may play a critical role in its antimicrobial activity as well as selectivities in different species.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Candida/efeitos dos fármacos , Peptídeos/química , Peptídeos/farmacologia , 1,2-Dipalmitoilfosfatidilcolina/metabolismo , Sequência de Aminoácidos , Anti-Infecciosos/síntese química , Anti-Infecciosos/metabolismo , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Peptídeos Catiônicos Antimicrobianos , Candida/crescimento & desenvolvimento , Dicroísmo Circular , Ligação de Hidrogênio , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Micelas , Testes de Sensibilidade Microbiana , Modelos Moleculares , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular , Peptídeos/síntese química , Peptídeos/metabolismo , Estrutura Secundária de Proteína , Soluções , Especificidade da Espécie , Relação Estrutura-Atividade , Ácido Trifluoracético/metabolismo , Água/metabolismo
13.
Protein Sci ; 9(7): 1294-303, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10933494

RESUMO

The active sites and substrate bindings of Rhizobium trifolii molonyl-CoA synthetase (MCS) catalyzing the malonyl-CoA formation from malonate and CoA have been determined based on NMR spectroscopy, site-directed mutagenesis, and comparative modeling methods. The MCS-bound conformation of malonyl-CoA was determined from two-dimensional-transferred nuclear Overhauser effect spectroscopy data. MCS protein folds into two structural domains and consists of 16 alpha-helices, 24 beta-strands, and several long loops. The core active site was determined as a wide cleft close to the end of the small C-terminal domain. The catalytic substrate malonate is placed between ATP and His206 in the MCS enzyme, supporting His206 in its catalytic role as it generates reaction intermediate, malonyl-AMP. These findings are strongly supported by previous biochemical data, as well as by the site-directed mutagenesis data reported here. This structure reveals the biochemical role as well as the substrate specificity that conservative residues of adenylate-forming enzymes have.


Assuntos
Proteínas de Bactérias , Coenzima A Ligases/química , Coenzima A Ligases/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Coenzima A/metabolismo , Coenzima A Ligases/genética , Malonatos/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Conformação Proteica
14.
Biochem J ; 344 Pt 1: 159-66, 1999 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-10548546

RESUMO

Malonyl-CoA synthetase (MCS) catalyses the formation of malonyl-CoA in a two-step reaction consisting of the adenylation of malonate with ATP followed by malonyl transfer from malonyl-AMP to CoA. In order to identify amino acid residues essential for each step of the enzyme, catalysis based on chemical modification and database analysis, Arg-168, Lys-170, and His-206 were selected for site-directed mutagenesis. Glutathione-S-transferase-fused enzyme (GST-MCS) was constructed and mutagenized to make R168G, K170M, R168G/K170M and H206L mutants, respectively. The MCS activity of soluble form GST-MCS was the same as that of wild-type MCS. Circular dichroism spectra for the four mutant enzymes were nearly identical to that for the GST-MCS, indicating that Arg-168, Lys-170 and His-206 are not important for conformation but presumably for substrate binding and/or catalysis. HPLC analysis of products revealed that the intermediate malonyl-AMP is not accumulated during MCS catalysis and that none of the mutant enzymes accumulated it either. Kinetic analysis of the mutants revealed that Lys-170 and His-206 play a critical role for ATP binding and the formation of malonyl-AMP, whereas Arg-168 is critical for formation of malonyl-CoA and specificity for malonyl-AMP. Molecular modelling based on the crystal structures of luciferase and gramicidin S synthetase 1 provided MCS structure which could fully explain all these biochemical data even though the MCS model was generated by comparative modelling.


Assuntos
Proteínas de Bactérias , Coenzima A Ligases/metabolismo , Rhizobium/enzimologia , Trifosfato de Adenosina/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Sequência de Bases , Domínio Catalítico/genética , Dicroísmo Circular , Coenzima A Ligases/química , Coenzima A Ligases/genética , Primers do DNA/genética , Cinética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Conformação Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Rhizobium/genética , Especificidade por Substrato
15.
Biochemistry ; 38(8): 2340-6, 1999 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-10029527

RESUMO

Single-chain monellin (SCM), which is an engineered 94-residue polypeptide, has proven to be as sweet as native two-chain monellin. SCM is more stable than the native monellin for both heat and acidic environments. Data from gel filtration HPLC and NMR indicate that the SCM exists as a monomer in aqueous solution. The solution structure of SCM has been determined by nuclear magnetic resonance (NMR) spectroscopy and dynamical simulated annealing calculations. A stable alpha-helix spanning residues Phe11-Ile26 and an antiparallel beta-sheet formed by residues 2-5, 36-38, 41-47, 54-64, 69-75, and 83-88 have been identified. The sheet was well defined by backbone-backbone NOEs, and the corresponding beta-strands were further confirmed by hydrogen bond networks based on amide hydrogen exchange data. Strands beta2 and beta3 are connected by a small bulge comprising residues Ile38-Cys41. A total of 993 distance and 56 dihedral angle restraints were used for simulated annealing calculations. The final simulated annealing structures (k) converged well with a root-mean-square deviation (rmsd) between backbone atoms of 0.49 A for secondary structural regions and 0.70 A for backbone atoms excluding two loop regions. The average restraint energy-minimized (REM) structure exhibited root-mean-square deviations of 1.19 A for backbone atoms and 0.85 A for backbone atoms excluding two loop regions with respect to 20 k structures. The solution structure of SCM revealed that the long alpha-helix was folded into the concave side of a six-stranded antiparallel beta-sheet. The side chains of Tyr63 and Asp66 which are common to all sweet peptides showed an opposite orientation relative to H1 helix, and they were all solvent-exposed. Residues at the proposed dimeric interface in the X-ray structure were observed to be mostly solvent-exposed and demonstrated high degrees of flexibility.


Assuntos
Simulação por Computador , Modelos Moleculares , Proteínas de Plantas/química , Edulcorantes/química , Algoritmos , Sequência de Aminoácidos , Cristalografia por Raios X , Computação Matemática , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular/métodos , Estrutura Secundária de Proteína , Soluções , Termodinâmica
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