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1.
J Public Health (Oxf) ; 40(4): e586-e593, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29688551

RESUMO

Background: Translational research is required to ensure exercise referral schemes (ERSs) are evidence-based and reflect local needs. This article reports process data from the co-development phase of an ERS, providing an insight into (i) factors that must be considered when translating evidence to practice in an ERS setting, and (ii) challenges and facilitators of conducting participatory research involving multiple stakeholders. Methods: An ERS was iteratively co-developed by a multidisciplinary stakeholder group (commissioners, managers, practitioners, patients and academics) via five participatory meetings and an online survey. Audio data (e.g. group discussions) and visual data (e.g. whiteboard notes) were recorded and analysed using NVivo-10 electronic software. Results: Factors to consider when translating evidence to practice in an ERS setting included (i) current ERS culture; (ii) skills, safety and accountability; and (iii) resources and capacity. The co-development process was facilitated by needs-analysis, open questions, multidisciplinary debate and reflective practice. Challenges included contrasting views, irregular attendance and (mis)perceptions of evaluation. Conclusion: The multidisciplinary co-development process highlighted cultural and pragmatic issues related to exercise referral provision, resulting in an evidence-based intervention framework designed to be implemented within existing infrastructures. Further work is required to establish the feasibility and effectiveness of the co-developed intervention in practice.


Assuntos
Exercício Físico , Encaminhamento e Consulta/organização & administração , Pesquisa Participativa Baseada na Comunidade , Humanos , Avaliação das Necessidades , Desenvolvimento de Programas , Inquéritos e Questionários , Pesquisa Translacional Biomédica
2.
Aliment Pharmacol Ther ; 39(10): 1213-24, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24654657

RESUMO

BACKGROUND: Risks and benefits of protease inhibitor (PI) (telaprevir or boceprevir) triple therapy in hepatitis C virus (HCV)-infected patients with mildly decompensated cirrhosis, including those wait-listed for liver transplantation (LT), are incompletely known. AIM: To assess virological responses and safety of PI triple therapy in patients with mildly decompensated Child-Pugh (CP) CP ≥6 vs. compensated (CP = 5) cirrhosis. METHODS: Multicentre cohort of 160 adults with cirrhosis treated with peginterferon/ribavirin (peg-IFN/RBV) plus telaprevir (69%) or boceprevir (31%), comparing outcomes between those with CP = 5 and CP ≥6. RESULTS: Patients, 47% with CP ≥6 cirrhosis (CP range 6-10), received PI triple therapy for a targeted duration of 48 weeks. The cohort was median age 59 years, 32% female, 59% genotype 1a, 35% previous null/partial responders. Sustained virological response at 12 weeks (SVR12) was achieved by 35% of patients with CP ≥6 vs. 54% of those with CP = 5 (P = 0.02). CP = 5, achievement of rapid virological response and genotype 1b/other, independently predicted SVR12. Compared to those with CP = 5, patients with CP ≥6 had more peg-IFN dose reductions, eltrombopag use, transfusions and hospitalisations to manage adverse events (all P < 0.05). Overall, 67 (42%) discontinued treatment early. Nine wait-listed patients were treated for a median of 97 days (IQR 60-160) prior to liver transplantation and five achieved post-LT SVR. CONCLUSIONS: In the presence of mild decompensation (Child-Pugh ≥6), SVR12 rates with protease inhibitor triple therapy are significantly reduced and adverse events increased. Thus, treatment with protease inhibitor triple therapy, if judged as necessary, should be undertaken with close monitoring and awareness of the significant risks.


Assuntos
Antivirais/uso terapêutico , Hepatite C Crônica/tratamento farmacológico , Cirrose Hepática/tratamento farmacológico , Antivirais/administração & dosagem , Antivirais/farmacologia , Estudos de Coortes , Quimioterapia Combinada , Feminino , Genótipo , Hepacivirus/genética , Humanos , Interferon-alfa/uso terapêutico , Cirrose Hepática/patologia , Transplante de Fígado , Masculino , Pessoa de Meia-Idade , Oligopeptídeos/administração & dosagem , Oligopeptídeos/farmacologia , Oligopeptídeos/uso terapêutico , Prolina/administração & dosagem , Prolina/análogos & derivados , Prolina/farmacologia , Prolina/uso terapêutico , Inibidores de Proteases/administração & dosagem , Inibidores de Proteases/farmacologia , Inibidores de Proteases/uso terapêutico , Estudos Retrospectivos , Ribavirina/administração & dosagem , Ribavirina/uso terapêutico , Índice de Gravidade de Doença
3.
J Anim Physiol Anim Nutr (Berl) ; 98(1): 56-64, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23298172

RESUMO

Previous studies from our laboratory have shown positive benefits of linoleic acid (LA) feeding for attenuation of rat heart failure (HF). However, another research group concluded LA feeding was detrimental to cardiac function, using the American Institute of Nutrition 76A (AIN) diet as a background diet for the experimental animals only. To reconcile these conflicting results and determine whether (i) AIN has effects on cardiovascular function, and (ii) AIN reverses the positive effects of LA feeding, studies were performed using spontaneously hypertensive heart failure (SHHF) rats in both a survival study with lifetime feeding of AIN (control: Purina 5001) and a 2 × 2 factorial design for 6 weeks in young male SHHF rats with background diet and LA as variables. During a lifetime of AIN feeding, mortality from heart failure is significantly accelerated, cardiolipin altered and triglycerides increased. In young rats, 6 weeks on the AIN diet promoted increased systolic and diastolic blood pressure, increased fed and fasting blood glucose, increased serum inflammatory eicosanoids, decreased docosahexanoic acid, increased posterior wall thickness in diastole and an altered cardiolipin subspecies profile. The addition of LA to the AIN diet was able to rescue blood pressure. However, the combination increased retroperitoneal fat mass, body weight and fed blood glucose beyond the levels with the AIN diet alone. Because the AIN diet has wide ranging effects on cardiovascular parameters, our results suggest that it should not be used in animal studies involving the cardiovascular system unless induction of cardiac dysfunction is the desired outcome.


Assuntos
Ração Animal/análise , Dieta , Insuficiência Cardíaca/induzido quimicamente , Animais , Pressão Sanguínea , Peso Corporal , Feminino , Masculino , Estado Nutricional , Ratos , Ratos Endogâmicos SHR
4.
AJNR Am J Neuroradiol ; 35(3): 609-14, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24029387

RESUMO

BACKGROUND AND PURPOSE: The clinical impact of facet joint bone scan activity is not fully understood. The hypothesis of this study is that facet joints targeted for percutaneous treatment in clinical practice differ from those with reported activity on technetium Tc99m methylene diphosphonate SPECT/CT. MATERIALS AND METHODS: All patients with a technetium Tc99m methylene diphosphonate SPECT/CT scan of the lumbar or cervical spine who underwent subsequent percutaneous facet joint steroid injection or comparative medial branch blocks at our institution between January 1, 2008, and February 19, 2013, were identified. Facet joints with increased activity were compared with those treated. A chart review characterized the clinical reasons for treatment discrepancies. RESULTS: Of 74 patients meeting inclusion criteria, 52 (70%) had discrepant imaging findings and treatment selection of at least 1 facet joint, whereas 34 patients (46%) had a side (right vs left) discrepancy. Only 92 (70%) of 132 facet joints with increased activity were treated, whereas 103 (53%) of 195 of treated facet joints did not have increased activity. The most commonly documented clinical rationale for discrepancy was facet joint activity that was not thought to correlate with clinical findings, cited in 18 (35%) of 52 patients. CONCLUSIONS: Facet joints undergoing targeted percutaneous treatment were frequently discordant with those demonstrating increased technetium Tc99m methylene diphosphonate activity identified by SPECT/CT at our institution, in many cases because the active facet joint(s) did not correlate with clinical findings. Further prospective double-blinded investigations of the clinical significance of facet joint activity by use of technetium Tc99m methylene diphosphonate SPECT/CT and comparative medial branch blocks are needed.


Assuntos
Compostos Radiofarmacêuticos , Medronato de Tecnécio Tc 99m , Tomografia Computadorizada de Emissão de Fóton Único , Articulação Zigapofisária/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Vértebras Cervicais/diagnóstico por imagem , Feminino , Humanos , Injeções Intra-Articulares , Vértebras Lombares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Bloqueio Nervoso
5.
Pediatr Radiol ; 31(12): 879-81, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11727025

RESUMO

We report a case of extramedullary hematopoiesis presenting as an adrenal mass in a young male with hereditary spherocytosis. The unilateral adrenal mass was discovered during an abdominal ultrasound performed for jaundice. CT and MR imaging were subsequently performed, followed by an excisional biopsy at the time of splenectomy and cholecystectomy. Although extramedullary hematopoiesis is a rare cause of an adrenal mass, the diagnosis must be considered in any patient with a history of a congenital hemolytic disorder such as hereditary spherocytosis. In this regard, the morbidity of an unnecessary procedure may be avoided.


Assuntos
Neoplasias das Glândulas Suprarrenais/diagnóstico , Hematopoese Extramedular , Esferocitose Hereditária/diagnóstico , Neoplasias das Glândulas Suprarrenais/diagnóstico por imagem , Criança , Diagnóstico Diferencial , Humanos , Imageamento por Ressonância Magnética , Masculino , Esferocitose Hereditária/diagnóstico por imagem , Esplenectomia , Tomografia Computadorizada por Raios X , Ultrassonografia
6.
7.
Toxicology ; 169(1): 1-15, 2001 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-11696405

RESUMO

An inflammatory response accompanies the reversible pneumotoxicity caused by butylated hydroxytoluene (BHT) administration to mice. Lung tumor formation is promoted by BHT administration following an initiating agent in BALB/cByJ mice, but not in CXB4 mice. To assess the contribution of inflammation to this differential susceptibility, we quantitatively characterized inflammation after one 150 mg/kg body weight, followed by three weekly 200 mg/kg ip injections of BHT into male mice of both strains. This examination included inflammatory cell infiltrate and protein contents in bronchoalveolar lavage (BAL) fluid, cyclooxygenase (COX)-1 and COX-2 expression in lung extracts, and PGE(2) and PGI(2) production by isolated bronchiolar Clara cells. BAL macrophage and lymphocyte numbers increased in BALB mice (P<0.0007 and 0.02, respectively), as did BAL protein content (P<0.05), COX-1 and COX-2 expression (P<0.05 for each), and PGI(2) production (P<0.05); conversely, these indices were not perturbed by BHT in CXB4 mice. BALB mice fed aspirin (400 mg/kg of chow) for two weeks prior to BHT treatment had reduced inflammatory cell infiltration. Our results support a hypothesis that resistance to BHT-induced inflammation in CXB4 mice accounts, at least in part, for the lack of effect of BHT on lung tumor multiplicity in this strain.


Assuntos
Antioxidantes/farmacologia , Hidroxitolueno Butilado/farmacologia , Carcinógenos/farmacologia , Neoplasias Pulmonares/induzido quimicamente , Pneumonia/induzido quimicamente , 6-Cetoprostaglandina F1 alfa/biossíntese , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Antioxidantes/toxicidade , Aspirina/farmacologia , Líquido da Lavagem Broncoalveolar/química , Hidroxitolueno Butilado/toxicidade , Carcinógenos/toxicidade , Ciclo-Oxigenase 1 , Ciclo-Oxigenase 2 , Dinoprostona/biossíntese , Immunoblotting , Técnicas Imunoenzimáticas , Imuno-Histoquímica , Isoenzimas/biossíntese , Pulmão/efeitos dos fármacos , Pulmão/enzimologia , Pulmão/patologia , Neoplasias Pulmonares/patologia , Masculino , Proteínas de Membrana , Camundongos , Camundongos Endogâmicos BALB C , Pneumonia/metabolismo , Pneumonia/patologia , Prostaglandina-Endoperóxido Sintases/biossíntese , Estatísticas não Paramétricas
8.
J Biol Chem ; 276(51): 48539-48, 2001 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-11602607

RESUMO

Two yeast enzymes, Psd1p and Psd2p, catalyze the decarboxylation of phosphatidylserine to produce phosphatidylethanolamine (PtdEtn). Mitochondrial Psd1p provides approximately 90% of total cellular phosphatidylserine decarboxylase activity. When the PSD1 gene is deleted, the resultant strain (psd1Delta) grows normally at 30 degrees C in glucose and in the absence of exogenous choline or ethanolamine. However, at elevated temperature (37 degrees C) or on the nonfermentable carbon source lactate, the growth of psd1Delta strains is minimal without ethanolamine supplementation. The reduced growth and viability correlate with a PtdEtn content below 4% of total phospholipid. These results suggest that there is a critical level of PtdEtn required to support growth. This theory is supported by growth data revealing that a psd1Delta psd2Delta dpl1Delta strain can only grow in the presence of ethanolamine. In contrast, a psd1Delta psd2Delta strain, which makes low levels of PtdEtn from sphingolipid breakdown, can be rescued by ethanolamine, choline, or the ethanolamine analogue propanolamine. psd1Delta psd2Delta cells grown in 2 mm propanolamine accumulate a novel lipid, which was determined by mass spectrometry to be phosphatidylpropanolamine (PtdPrn). PtdPrn can comprise up to 40% of the total phospholipid content in supplemented cells at the expense of phosphatidylcholine and PtdEtn. The absolute level of PtdEtn required for growth when PtdPrn is present appears to be 1% of the total phospholipid content. The essential function of the PtdEtn in the presence of propanolamine does not appear to be the formation of hexagonal phase lipid, insofar as PtdPrn readily forms hexagonal phase structures detectable by (31)P NMR.


Assuntos
Fosfatidiletanolaminas/fisiologia , Saccharomyces cerevisiae/fisiologia , Cromatografia Líquida , Espectrometria de Massas , Ressonância Magnética Nuclear Biomolecular , Fenótipo , Fosfatidiletanolaminas/química , Propanolaminas/metabolismo , Conformação Proteica , Saccharomyces cerevisiae/crescimento & desenvolvimento
9.
J Pharmacol Exp Ther ; 299(2): 691-7, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11602682

RESUMO

Leukotriene B4 (LTB4) is a potent mediator of inflammation that recruits granulocytes to the site of injury during the inflammatory response. The biological activity of LTB4 is terminated by its metabolism into inactive metabolites. Recent studies have suggested that LTB4 may have additional activity as an endogenous ligand for the transcription factor peroxisome proliferator-activated receptor alpha (PPARalpha). Based on the data presented, a model was proposed in which LTB4 acts in a negative feedback manner by inducing the transcription of genes involved its own metabolism. In the present study the effect of PPARalpha activation on LTB4 metabolism was directly investigated. Primary cultures of rat hepatocytes were treated with LTB4 or the PPARalpha agonist WY-14,643, and LTB4 metabolism was assessed by measuring levels of LTB4 and the formation of LTB4 metabolites. In addition, the effect of PPARalpha activation on levels of acyl-CoA oxidase mRNA and expression of CYP4F proteins, which are specific omega-hydroxylases for LTB4, was determined. Treatment of hepatocytes with WY-14,643, but not LTB4, was found to increase acyl-CoA oxidase mRNA and enhance expression of rat hepatic CYP4F proteins and CYP4A1. Neither WY-14,643 nor LTB4 caused an increase of the basal levels of LTB4 metabolism, and no novel metabolites were observed. These results do not support the hypothesis that a pathway of negative feedback regulation of LTB4 metabolism involving PPARalpha exists in hepatocytes, because activation of PPARalpha by LTB4 or other PPARalpha agonists did not correlate with an increase in LTB4 metabolism.


Assuntos
Hepatócitos/metabolismo , Leucotrieno B4/metabolismo , Receptores Citoplasmáticos e Nucleares/fisiologia , Fatores de Transcrição/fisiologia , Animais , Biotransformação , Northern Blotting , Cromatografia Líquida de Alta Pressão , Hepatócitos/efeitos dos fármacos , Técnicas In Vitro , Masculino , Microssomos Hepáticos/metabolismo , RNA Mensageiro/biossíntese , RNA Mensageiro/isolamento & purificação , Ratos , Ratos Sprague-Dawley , Receptores Citoplasmáticos e Nucleares/agonistas , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Ultravioleta , Fatores de Transcrição/agonistas
10.
J Am Soc Mass Spectrom ; 12(7): 763-71, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11444597

RESUMO

The cysteinyl leukotrienes, LTC4, LTD4 and LTE4, and the recently described cysteinyl eicosanoid, 5-oxo-7-glutathionyl-8,11,14-eicosatrienoic acid (FOG7) have been analyzed by tandem mass spectrometry. Both [M-H]- and [M+H]+ ions were produced by electrospray ionization and collision-induced dissociation of these molecular ion species were studied using both an ion trap and a triple quadrupole instrument. Product ion spectra obtained were characteristic of the structure of the cysteinyl leukotrienes and mechanisms of ion formation were investigated by using deuterium-labeled analogs. The product ion spectrum obtained following collision-induced dissociation of the [M-H]- anion from FOG7 was devoid of significant structural information and further studies of collision activation of the [M+H]+ spectrum were therefore examined. Positive ion MS3 spectra obtained in the ion trap from the gamma-glutamate cleavage products of FOG7 and its derivative (d7-FOG7) afforded an abundant ion not observed in spectra generated from the cysteinyl leukotrienes. Formation of this fragment ion likely occurred via a McLafferty-type rearrangement to afford cleavage of the C6-C7 bond adjacent to the sulfur atom and was valuable for the identification of the structure of FOG7 and defining the biosynthetic pathway as a 1,4-Michael addition of glutathione to 5-oxo-eicosatetraenoic acid (5-oxo-ETE).


Assuntos
Ácido Araquidônico/análise , Fatores Quimiotáticos/análise , Glutationa/análise , Leucotrieno C4/análise , Ácido Araquidônico/síntese química , Fatores Quimiotáticos/síntese química , Glutationa/síntese química , Leucotrieno C4/síntese química , Espectrometria de Massas por Ionização por Electrospray
11.
Proc Natl Acad Sci U S A ; 98(12): 6877-82, 2001 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-11381122

RESUMO

The expression of virulence determinants in Staphylococcus aureus is controlled by global regulatory loci (e.g., sarA and agr). The sar (Staphylococcus accessory regulator) locus is composed of three overlapping transcripts (sarA P1, P3, and P2, transcripts initiated from the P1, P3, and P2 promoters, respectively), all encoding the 124-aa SarA protein. The level of SarA, the major regulatory protein, is partially controlled by the differential activation of the sarA promoters. We previously partially purified a 13.6-kDa protein, designated SarR, that binds to the sarA promoter region to down-modulate sarA transcription from the P1 promoter and subsequently SarA expression. SarR shares sequence similarity to SarA, and another SarA homolog, SarS. Here we report the 2.3 A-resolution x-ray crystal structure of the dimeric SarR-MBP (maltose binding protein) fusion protein. The structure reveals that the SarR protein not only has a classic helix-turn-helix module for DNA binding at the major grooves, but also has an additional loop region involved in DNA recognition at the minor grooves. This interaction mode could represent a new functional class of the "winged helix" family. The dimeric SarR structure could accommodate an unusually long stretch of approximately 27 nucleotides with two or four bending points along the course, which could lead to the bending of DNA by 90 degrees or more, similar to that seen in the catabolite activator protein (CAP)-DNA complex. The structure also demonstrates the molecular basis for the stable dimerization of the SarR monomers and possible motifs for interaction with other proteins.


Assuntos
Proteínas de Bactérias/química , Staphylococcus aureus/química , Transativadores , Sequência de Aminoácidos , Cristalização , DNA/metabolismo , Dimerização , Dados de Sequência Molecular
13.
FEBS Lett ; 497(2-3): 73-6, 2001 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-11377415

RESUMO

The molecular mechanism(s) by which Bcl-2 regulates apoptosis is poorly understood. Bcl-2 suppresses apoptosis by inhibiting calcium activation of the permeability transition of mitochondria. In this patch-clamp study, overexpression of Bcl-2 in mitochondria of cultured cells suppressed calcium activation of a high conductance channel that may underlie the permeability transition. All other single channel parameters were identical when multiple conductance channel activities of mitochondria from control and Bcl-2 overexpressing cells were compared. Bcl-2 forms channels in artificial membranes; however, no novel channel activities could be linked to Bcl-2 overexpression, suggesting Bcl-2 does not form channels in native inner membranes of mitochondria.


Assuntos
Neoplasias da Mama/metabolismo , Cálcio/metabolismo , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Western Blotting , Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Canais de Cálcio/metabolismo , Relação Dose-Resposta a Droga , Feminino , Humanos , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/metabolismo , Mitocôndrias/efeitos dos fármacos , Técnicas de Patch-Clamp , Permeabilidade/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/farmacologia , Transfecção , Células Tumorais Cultivadas
14.
J Lipid Res ; 42(4): 587-96, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11290831

RESUMO

Unmitigated oxidative stress is deleterious, as epitomized by CCl4 intoxication. In this well-characterized model of free radical-initiated damage, liver metabolism of CCl4 to CCl3. causes lipid peroxidation, F-ring isoprostane formation, and pathologic leukocyte activation. The nature of the mediator that couples oxidation to the hepatotoxic inflammatory response is uncharacterized. We found that oxidatively modified phosphatidylcholines were present in the livers of CCl4-exposed rats and not in livers from control animals, that CCl4 metabolism generated lipids that activated 293 cells stably transfected with the human platelet-activating factor (PAF) receptor, and that this PAF-like activity was formed as rapidly as isoprostane-containing phosphatidylcholine (iPC) during oxidation. iPC and the PAF-like activity also had similar chromatographic properties. The potential for iPC activation of the PAF receptor has been unexplored, but we conclude that iPC themselves did not activate the PAF receptor, as phospholipase A1 hydrolysis completely destroyed iPC, but none of the PAF-like bioactivity. Oxidatively fragmented phospholipids are potent agonists of the PAF receptor, but mass spectrometry characterized PAF as the major inflammatory component coeluting with iPC. Oxidatively fragmented phospholipids and iPC are markers of free radical generation in CCl4-intoxicated liver, but PAF generation by activated hepatic cells generated the inflammatory agent.


Assuntos
Tetracloreto de Carbono/metabolismo , Diterpenos , Mediadores da Inflamação/metabolismo , Fígado/metabolismo , Fosfatidilcolinas/metabolismo , Fator de Ativação de Plaquetas/metabolismo , Glicoproteínas da Membrana de Plaquetas/metabolismo , Receptores de Superfície Celular , Receptores Acoplados a Proteínas G , Animais , Tetracloreto de Carbono/toxicidade , Linhagem Celular , Cromatografia Líquida de Alta Pressão , Corantes Fluorescentes/metabolismo , Sequestradores de Radicais Livres/farmacologia , Radicais Livres/metabolismo , Fura-2/análogos & derivados , Fura-2/metabolismo , Ginkgolídeos , Humanos , Inflamação/metabolismo , Lactonas/farmacologia , Lipoproteínas LDL/metabolismo , Oxirredução , Fosfatidilcolinas/química , Fosfolipases A/farmacologia , Fosfolipases A1 , Fator de Ativação de Plaquetas/química , Ratos , Proteínas Recombinantes/metabolismo
15.
J Biol Chem ; 276(19): 16015-23, 2001 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-11279149

RESUMO

Synthetic high affinity peroxisome proliferator-activated receptor (PPAR) agonists are known, but biologic ligands are of low affinity. Oxidized low density lipoprotein (oxLDL) is inflammatory and signals through PPARs. We showed, by phospholipase A(1) digestion, that PPARgamma agonists in oxLDL arise from the small pool of alkyl phosphatidylcholines in LDL. We identified an abundant oxidatively fragmented alkyl phospholipid in oxLDL, hexadecyl azelaoyl phosphatidylcholine (azPC), as a high affinity ligand and agonist for PPARgamma. [(3)H]azPC bound recombinant PPARgamma with an affinity (K(d)((app)) approximately 40 nm) that was equivalent to rosiglitazone (BRL49653), and competition with rosiglitazone showed that binding occurred in the ligand-binding pocket. azPC induced PPRE reporter gene expression, as did rosiglitazone, with a half-maximal effect at 100 nm. Overexpression of PPARalpha or PPARgamma revealed that azPC was a specific PPARgamma agonist. The scavenger receptor CD36 is encoded by a PPRE-responsive gene, and azPC enhanced expression of CD36 in primary human monocytes. We found that anti-CD36 inhibited azPC uptake, and it inhibited PPRE reporter induction. Results with a small molecule phospholipid flippase mimetic suggest azPC acts intracellularly and that cellular azPC accumulation was efficient. Thus, certain alkyl phospholipid oxidation products in oxLDL are specific, high affinity extracellular ligands and agonists for PPARgamma that induce PPAR-responsive genes.


Assuntos
Lipoproteínas LDL/metabolismo , Monócitos/metabolismo , Fosfatidilcolinas/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Tiazolidinedionas , Fatores de Transcrição/metabolismo , Animais , Sítios de Ligação , Ligação Competitiva , Antígenos CD36/fisiologia , Linhagem Celular , Proteínas de Ligação a DNA/metabolismo , Genes Reporter , Humanos , Técnicas In Vitro , Cinética , Ligantes , Oxirredução , Fosfatidilcolinas/química , Receptores Citoplasmáticos e Nucleares/agonistas , Receptores Citoplasmáticos e Nucleares/genética , Proteínas Recombinantes de Fusão/metabolismo , Rosiglitazona , Tiazóis/farmacocinética , Fatores de Transcrição/agonistas , Fatores de Transcrição/genética , Transfecção
16.
J Pharmacol Exp Ther ; 296(2): 293-305, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11160610

RESUMO

The metabolism of arachidonic acid by the 5-lipoxygenase pathway not only leads to the formation of leukotrienes but also to the biologically active eicosanoid 5-oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE). The synthesis of 5-oxo-ETE was investigated in the elicited peritoneal macrophage and the formation of 5-hydroxyeicosatetraenoic acid (5-HETE) as well as 5-oxo-ETE was quantitated using stable isotope dilution tandem mass spectrometry. The metabolism of 5-oxo-ETE in these same cells led to the formation of a series of novel less lipophilic metabolites oxidized near the methyl terminus that were structurally characterized using electrospray LC/MS and LC/MS/MS. Five novel metabolites of 5-oxo-ETE were identified including 5,18-diHETE, 5,19-diHETE, 5-oxo-19-HETrE, 5-oxo-18-HETrE, and 5,19-diHETrE. These metabolites corresponded to omega-1 and omega-2 oxidation of 5-oxo-ETE presumably formed by a specific cytochrome P450. There was no evidence for the formation of omega-oxidation (20-hydroxy metabolites), which are known products of metabolism of 5-oxo-ETE in other cell types. None of the metabolites were found to elevate intracellular calcium release, suggesting that this metabolic pathway may result in inactivation of 5-oxo-ETE. This is the first report of the biosynthesis of 5-oxo-ETE by tissue resident cell outside of the blood and the formation of novel omega-1 and omega-2 oxidation of this eicosanoid.


Assuntos
Ácidos Araquidônicos/síntese química , Macrófagos/metabolismo , Animais , Ácidos Araquidônicos/metabolismo , Biotransformação , Cálcio/metabolismo , Catálise , Separação Celular , Cromatografia Líquida de Alta Pressão , Citosol/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Hidrogênio/química , Ácidos Hidroxieicosatetraenoicos/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Oxirredução , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Ultravioleta
17.
Mol Ther ; 3(1): 113-21, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11162318

RESUMO

Organotypic slice cultures from postnatal day 12 mouse cerebellum were transfected using three nonviral methods: biolistics (gene gun), lipotransfection, and electroporation. The plasmid transferred, pHD17-25Q-GFP, encoded a fusion protein with a green fluorescent protein (GFP) component. Optimal conditions for both lipotransfection and electroporation are the same as those previously found in live animal models. Electroporation (26 +/- 6) and biolistics (34 +/- 4.4) provide a better rate of transfer than lipotransfection (15 +/- 2.2) in slice cultures and are comparable to each other. Each of the transfer methods produced positive signals in a heterogeneous population of glial and neuronal cells. These data provide a base for optimal transfection of slice cultures, allowing the development of therapeutic constructs, and support the idea that successful refinement of nonviral delivery methods for in vivo use is possible using brain slice cultures.


Assuntos
Biolística/métodos , Sistema Nervoso Central/citologia , Eletroporação/métodos , Técnicas de Transferência de Genes , Transfecção/métodos , Animais , Relação Dose-Resposta a Droga , Proteínas de Fluorescência Verde , Imuno-Histoquímica , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Plasmídeos/genética , Plasmídeos/metabolismo
18.
Free Radic Biol Med ; 29(7): 620-32, 2000 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-11033414

RESUMO

Oxidation of 1-O-hexadec-1'-enyl-arachidonoyl glycerophosphocholine (16:0p/20:4-GPC) by hydroxyl radical generated from Cu(II)/H(2)O(2) was found to yield major products corresponding to free carboxylic acids of 5-hydroxyeicosatetraenoic acid and several 5, 12-dihydroxyeicosatetraenoic acid. These products were characterized by electrospray tandem mass spectrometry based upon characteristic product ion spectra, as well as HPLC retention time. Several products were found to be biologically active in terms of elevating neutrophil intracellular calcium ion concentration. When mixed micelles of 16:0p/20:4-GPC were treated with Cu(II)/H(2)O(2), oxidation of the arachidonate esterified to the plasmalogen glycerophosphocholine lipid resulted in the most abundant products oxidized at carbon-5 of esterified arachidonate, but free carboxylic acid products were not formed. The mechanism of formation of these oxidized products is suggested to involve a cooperation between the sn-1 vinyl ether substituent and the arachidonoyl substituent at sn-2 of the glycerophospholipid to direct oxidation of the arachidonate ester at carbon-5. Since arachidonic acid is found in high abundance within most plasmalogen glycerophospholipids, the susceptibility of plasmalogens to free radical oxidation likely involves concomitant oxidation of the arachidonyl radyl group esterified at the sn-2 position.


Assuntos
Ácido Araquidônico/química , Ácidos Carboxílicos/química , Ésteres/síntese química , Glicerilfosforilcolina/química , Ácidos Hidroxieicosatetraenoicos/química , Cromatografia Líquida de Alta Pressão , Cobre , Glicerilfosforilcolina/análogos & derivados , Peróxido de Hidrogênio , Espectrometria de Massas , Micelas , Oxirredução , Relação Estrutura-Atividade , Trítio
19.
Free Radic Biol Med ; 28(12): 1762-70, 2000 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-10946218

RESUMO

Oxidation of phospholipids results in chain-shortened fragments and oxygenated derivatives of polyunsaturated sn-2 fatty acyl residues, generating a myriad of phospholipid products. Certain oxidation products of phosphatidylcholine bind to and activate the human receptor for PAF, and these PAF-like lipids are potent, selective inflammatory mediators. Formation of PAF-like lipids is nonenzymatic and so their accumulation is unregulated. PAF-like lipids are produced in vivo in response to oxidative stresses and are responsible for attendant acute inflammatory responses. PAF-like lipids almost exclusively contain an ether-linked alkyl residue at the sn-1 position of the phosphatidylcholine backbone and molecular identification of these is facilitated by phospholipase A(1) treatment to remove the bulk of the inactive phospholipids. The identity of biologically active species generated by oxidative fragmentation and oxidation can be elucidated by understanding relevant reactions leading to the formation of PAF-like lipids, and then their structure can be established by tandem mass spectrometry and chemical synthesis.


Assuntos
Peroxidação de Lipídeos/fisiologia , Fosfolipídeos/química , Fosfolipídeos/metabolismo , Receptores de Superfície Celular , Receptores Acoplados a Proteínas G , Animais , Cricetinae , Radicais Livres/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Glicerofosfolipídeos/química , Glicerofosfolipídeos/metabolismo , Humanos , Inflamação/induzido quimicamente , Inflamação/metabolismo , Lipoproteínas LDL/metabolismo , Espectrometria de Massas , Oxirredução , Fosfatidilcolinas/química , Fator de Ativação de Plaquetas/metabolismo , Glicoproteínas da Membrana de Plaquetas/metabolismo , Fumaça/efeitos adversos
20.
J Biol Chem ; 275(39): 29931-4, 2000 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-10924496

RESUMO

A biologically active glutathione adduct of the eicosanoid 5-oxo-eicosatetraenoic acid has been observed as a product formed within the murine peritoneal macrophage. This five-oxo glutathione adduct (FOG(7)) was structurally characterized using electrospray tandem mass spectrometry as a 1,4 Michael addition product 5-oxo-7-glutathionyl-8,11,14-eicosatrienoic acid. FOG(7) was found to be highly potent in stimulating eosinophil as well as neutrophil chemotaxis, also capable of initiating actin polymerization, without elevating intracellular free calcium ion concentration within either the eosinophil or polymorphonuclear leukocyte. These biological responses suggest that either FOG(7) activates a subset of receptors mediating the broader biological activity of the parent eicosanoid 5-oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE) or that a receptor not activated by 5-oxo-ETE participates in the chemotactic activity of FOG(7). The only other known biologically active glutathione adduct has been leukotriene C(4) (LTC(4)), another eicosanoid that exerts potent effects through the Cys-LT receptor. The biochemical parallel between the formation of LTC(4) and FOG(7) suggests an interesting mechanism by which biologically active eicosanoids derived from electrophilic intermediates may have unique distribution and prolonged efficacy in vivo.


Assuntos
Ácido Araquidônico/química , Fatores Quimiotáticos/farmacologia , Quimiotaxia de Leucócito , Glutationa/química , Granulócitos/efeitos dos fármacos , Actinas , Animais , Eosinófilos/efeitos dos fármacos , Citometria de Fluxo , Humanos , Leucotrieno C4/análogos & derivados , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Peso Molecular , Neutrófilos/efeitos dos fármacos
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