Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 106
Filtrar
1.
Ultrasound Obstet Gynecol ; 62(2): 248-254, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36971026

RESUMO

OBJECTIVE: To examine the relationship between umbilical cord insertion site, placental pathology and adverse pregnancy outcome in a cohort of normal and complicated pregnancies. METHODS: Sonographic measurement of the cord insertion and detailed placental pathology were performed in 309 participants. Associations between cord insertion site, placental pathology and adverse pregnancy outcome (pre-eclampsia, preterm birth, small-for-gestational age) were examined. RESULTS: A total of 93 (30%) participants were identified by pathological examination to have a peripheral cord insertion site. Only 41 of the 93 (44%) peripheral cords were detected by prenatal ultrasound. Peripherally inserted cords were associated significantly (P < 0.0001) with diagnostic placental pathology (most commonly with maternal vascular malperfusion (MVM)); of which 85% had an adverse pregnancy outcome. In cases of isolated peripheral cords, without placental pathology, the incidence of adverse outcome was not statistically different when compared to those with central cord insertion and no placental pathology (31% vs 18%; P = 0.3). A peripheral cord with an abnormal umbilical artery (UA) pulsatility index (PI) corresponded to an adverse outcome in 96% of cases compared to 29% when the UA-PI was normal. CONCLUSIONS: This study demonstrates that peripheral cord insertion is often part of the spectrum of findings of MVM disease and is associated with adverse pregnancy outcome. However, adverse outcome was uncommon when there was an isolated peripheral cord insertion and no placental pathology. Therefore, additional sonographic and biochemical features of MVM should be sought when a peripheral cord is observed. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.


Assuntos
Placenta , Resultado da Gravidez , Cordão Umbilical , Feminino , Humanos , Recém-Nascido , Gravidez , Placenta/patologia , Nascimento Prematuro , Artérias Umbilicais/diagnóstico por imagem , Cordão Umbilical/diagnóstico por imagem , Cordão Umbilical/patologia
2.
Cytokine ; 96: 274-278, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28554144

RESUMO

Excessive inflammation reduces skeletal muscle protein synthesis leading to wasting and weakness. The janus kinase/signal transducers and activators of transcription-3 (JAK/STAT3) pathway is important for the regulation of inflammatory signaling. As such, suppressor of cytokine signaling-3 (SOCS3), the negative regulator of JAK/STAT signaling, is thought to be important in the control of muscle homeostasis. We hypothesized that muscle-specific deletion of SOCS3 would impair the anabolic response to leucine during an inflammatory insult. Twelve week old (n=8 per group) SOCS3 muscle-specific knockout mice (SOCS3-MKO) and littermate controls (WT) were injected with lipopolysaccharide (LPS, 1mg/kg) or saline and were studied during fasted conditions or after receiving 0.5g/kg leucine 3h after the injection of LPS. Markers of inflammation, anabolic signaling, and protein synthesis were measured 4h after LPS injection. LPS injection robustly increased mRNA expression of inflammatory molecules (Socs3, Socs1, Il-6, Ccl2, Tnfα and Cd68). In muscles from SOCS3-MKO mice, the Socs3 mRNA response to LPS was significantly blunted (∼6-fold) while STAT3 Tyr705 phosphorylation was exacerbated (18-fold). Leucine administration increased protein synthesis in both WT (∼1.6-fold) and SOCS3-MKO mice (∼1.5-fold) compared to basal levels. LPS administration blunted this effect, but there were no differences between WT and SOCS3-MKO mice. Muscle-specific SOCS3 deletion did not alter the response of AKT, mTOR, S6 or 4EBP1 under any treatment conditions. Therefore, SOCS3 does not appear to mediate the early inflammatory or leucine-induced changes in protein synthesis in skeletal muscle.


Assuntos
Anabolizantes , Inflamação/metabolismo , Leucina/administração & dosagem , Músculo Esquelético/metabolismo , Biossíntese de Proteínas , Proteína 3 Supressora da Sinalização de Citocinas/fisiologia , Animais , Quimiocina CCL2/genética , Modelos Animais de Doenças , Interleucina-6/genética , Leucina/metabolismo , Lipopolissacarídeos/administração & dosagem , Masculino , Camundongos , Camundongos Knockout , Fosforilação , Fator de Transcrição STAT3/metabolismo , Proteína 3 Supressora da Sinalização de Citocinas/deficiência , Proteína 3 Supressora da Sinalização de Citocinas/genética , Fator de Necrose Tumoral alfa/genética
3.
Minerva Cardioangiol ; 63(3): 217-29, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25690178

RESUMO

In the recent years it has become apparent that angiography-based assessment of coronary artery stenosis suffers from considerable inaccuracy and pitfalls. Besides interobserver variability in assessing stenosis severity, the correlation between angiographic severity and ischemia is suboptimal. Percutaneous coronary intervention (PCI) guided by the physiologic lesion assessment employing fractional flow reserve (FFR) is rendered superior to angiographic lesion assessment and proven to improve cardiovascular outcomes and reduce cost. In this manuscript we discuss the accepted and emerging clinical indications for FFR use. The correlation between FFR and symptoms, stress imaging and intravascular ultrasound are reviewed along with the inherent limitations and pitfalls of these diagnostic technologies. The data regarding the correlation between Instantaneous (vasodilator free) wave-free ratio (iFR) and conventional FFR is summarized.


Assuntos
Angiografia Coronária/métodos , Estenose Coronária/diagnóstico , Reserva Fracionada de Fluxo Miocárdico , Estenose Coronária/fisiopatologia , Estenose Coronária/terapia , Humanos , Isquemia Miocárdica/diagnóstico , Isquemia Miocárdica/fisiopatologia , Variações Dependentes do Observador , Intervenção Coronária Percutânea/métodos , Índice de Gravidade de Doença , Vasodilatadores/administração & dosagem
4.
Thromb Haemost ; 112(2): 323-31, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24763965

RESUMO

Aspirin and statin therapy are mainstay treatments in patients with coronary artery disease (CAD). The relation between statin therapy, in vivo thromboxane (Tx) generation; a marker of inflammation, and blood thrombogenicity has never been explored. Urinary 11-dehydro (dh) TxB2 was determined in patients with suspected CAD on 325 mg daily aspirin therapy prior to undergoing cardiac catheterisation (n=281). Thrombogenicity was estimated by thrombelastographic measurement of thrombin-induced platelet-fibrin clot strength (TIP-FCS) and lipids/lipoproteins were determined by vertical density gradient ultracentrifugation/ELISA. The influence of statin therapy and dose was analysed by the atorvastatin equivalent dose (5-10 mg, 20-40 mg, or 80 mg daily). Statin therapy (n=186) was associated with a dose-dependent reduction in urinary 11-dh TxB2 (p=0.046) that was independent of LDL and apo B100 levels but was strongly related to TIP-FCS (p=0.006). By multivariate analysis, no statin therapy (n=95) and female gender were independently associated with high urinary 11-dh TxB2 [OR=2.95 (0.1.57-5.50, p=0.0007); OR=2.25 (1.24-4.05, p=0.007)], respectively. In aspirin-treated patients, statin therapy was independently and inversely associated with inflammation in a dose-dependent manner. Elevated 11-dh TxB2 was associated with a prothrombotic state indicated by high TIP-FCS. Our data suggest that measurement of urinary 11-dTxB2 may be a useful method to optimise statin dosing in order to reduce thrombotic risk.


Assuntos
Aspirina/administração & dosagem , Doença da Artéria Coronariana/tratamento farmacológico , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Mediadores da Inflamação/urina , Inibidores da Agregação Plaquetária/administração & dosagem , Tromboxano B2/análogos & derivados , Idoso , Biomarcadores/urina , Coagulação Sanguínea/efeitos dos fármacos , Distribuição de Qui-Quadrado , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/urina , Relação Dose-Resposta a Droga , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Modelos de Riscos Proporcionais , Fatores de Risco , Fatores Sexuais , Tromboelastografia , Tromboxano B2/urina , Resultado do Tratamento , Ultracentrifugação
5.
J Mol Cell Cardiol ; 65: 67-75, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24080183

RESUMO

Cardiac metabolic stress is a hallmark of many cardiac pathologies, including diabetes. Cardiac glycogen mis-handling is a frequent manifestation of various cardiopathologies. Diabetic females have a higher risk of heart disease than males, yet sex disparities in cardiac metabolic stress settings are not well understood. Oestrogen acts on key glycogen regulatory proteins. The goal of this study was to evaluate sex-specific metabolic stress-triggered cardiac glycogen handling responses. Male and female adult C57Bl/6J mice were fasted for 48h. Cardiac glycogen content, particle size, regulatory enzymes, signalling intermediates and autophagic processes were evaluated. Female hearts exhibited 51% lower basal glycogen content than males associated with lower AMP-activated-kinase (AMPK) activity (35% decrease in pAMPK:AMPK). With fasting, glycogen accumulated in female hearts linked with decreased particle size and upregulation of Akt and AMPK signalling, activation of glycogen synthase and inactivation of glycogen phosphorylase. Fasting did not alter glycogen content or regulatory proteins in male hearts. Expression of glycogen autophagy marker, starch-binding-protein-domain-1 (STBD1), was 63% lower in female hearts than males and increased by 69% with fasting in females only. Macro-autophagy markers, p62 and LC3BII:I ratio, increased with fasting in male and female hearts. This study identifies glycogen autophagy ('glycophagy') as a potentially important component of the response to cardiac metabolic stress. Glycogen autophagy occurs in association with a marked and selective accumulation of glycogen in the female myocardium. Our findings suggest that sex-specific differences in glycogen handling may have cardiopathologic consequences in various settings, including diabetic cardiomyopathy.


Assuntos
Autofagia , Glicogênio/metabolismo , Miocárdio/metabolismo , Estresse Fisiológico , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Biomarcadores/metabolismo , Jejum/metabolismo , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miocárdio/ultraestrutura , Tamanho da Partícula , Proteínas Proto-Oncogênicas c-akt/metabolismo , Caracteres Sexuais , Transdução de Sinais
6.
Minerva Cardioangiol ; 61(3): 281-93, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23681131

RESUMO

The adoption of early revascularization as the preferred strategy in all ST-elevation myocardial infarctions (STEMI) and high risk acute coronary syndromes (ACS) without ST elevation resulted in a considerable reduction in the incidence of post-ACS cardiogenic shock (CS) however the incidence of CS on hospital arrival has not changed. In-hospital and 30 day mortality from CS remains excessively high in facilities with coronary revascularization capabilities. Trials investigating the incremental value of either intra-aortic counter-pulsation (IACP) or advanced MCS did not demonstrate a meaningful mortality reduction. Mortality remains 45-60% and depends on clinical characteristics of the patient, timely and successful revascularization and advanced MCS in suitable candidates. Most CS survivors demonstrate satisfactory functional capacity and quality of life. The authors propose the "Guthrie classification" for post-ACS CS. This classification promotes better characterization of CS patients enrolled in clinical trials and registries. It also allows the clinician to better define the goals and benefits of therapy for the CS subjects. The precise pathophysiology of post-ACS CS remains poorly understood at the biochemical and cellular level. Uncovering and modifying these processes remains key to any fundamental change in post-ACS CS outcomes.


Assuntos
Síndrome Coronariana Aguda/terapia , Angioplastia Coronária com Balão , Infarto do Miocárdio/terapia , Choque Cardiogênico/prevenção & controle , Choque Cardiogênico/terapia , Tempo para o Tratamento , Síndrome Coronariana Aguda/mortalidade , Síndrome Coronariana Aguda/fisiopatologia , Angioplastia Coronária com Balão/métodos , Cardiotônicos/uso terapêutico , Ensaios Clínicos como Assunto , Dopamina/uso terapêutico , Quimioterapia Combinada , Sistema de Condução Cardíaco/fisiopatologia , Humanos , Incidência , Infarto do Miocárdio/mortalidade , Infarto do Miocárdio/fisiopatologia , Norepinefrina/uso terapêutico , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Respiração Artificial , Prevenção Secundária , Choque Cardiogênico/etiologia , Choque Cardiogênico/mortalidade , Choque Cardiogênico/fisiopatologia , Taxa de Sobrevida , Resultado do Tratamento , Estados Unidos/epidemiologia , Vasoconstritores/uso terapêutico
7.
Diabetologia ; 56(3): 675-9, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23242170

RESUMO

AIMS/HYPOTHESIS: A key morphological feature of diabetic nephropathy is the accumulation and deposition of glycogen in renal tubular cells, known as Armanni-Ebstein lesions. While this observation has been consistently reported for many years, the molecular basis of these lesions remains unclear. METHODS: Using biochemical and histochemical methods, we measured glycogen concentration, glycogen synthase and glycogen phosphorylase enzyme activities, and mRNA expression and protein levels of glycogenin in kidney lysates from control and transgenic (mRen-2)27 rat models of diabetes that had been treated with and without a new anti-fibrotic agent, FT011. RESULTS: Diabetic nephropathy was associated with increased glycogen content, increased glycogen synthase activity and decreased glycogen phosphorylase activity. Glycogenin, the key protein responsible for initiating the synthesis of each glycogen particle, had very high levels in the diabetic kidney together with increased mRNA expression compared with control kidneys. Treatment with FT011 did not change glycogen synthase or glycogen phosphorylase enzyme activities but prevented both glycogenin mRNA synthesis and accumulation of Armanni-Ebstein lesions in the diabetic kidney. CONCLUSIONS/INTERPRETATION: Armanni-Ebstein lesions found in diabetic nephropathy are due to aberrant glycogenin protein levels and mRNA expression, providing an explanation for the increased glycogen concentration found within the diabetic kidney. FT011 treatment in diabetic rats reduced glycogenin levels and, subsequently, renal glycogen concentration.


Assuntos
Anti-Inflamatórios/uso terapêutico , Ácidos Cafeicos/uso terapêutico , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/enzimologia , ortoaminobenzoatos/uso terapêutico , Animais , Nefropatias Diabéticas/metabolismo , Ativação Enzimática/efeitos dos fármacos , Feminino , Glucosiltransferases/metabolismo , Glicogênio/metabolismo , Glicogênio Fosforilase/metabolismo , Glicogênio Sintase/metabolismo , Glicoproteínas/metabolismo , Ratos , Ratos Transgênicos
8.
Am J Physiol Renal Physiol ; 300(6): F1437-47, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21429972

RESUMO

Deficiency of the intrinsic lysosomal protein human scavenger receptor class B, member 2 (SCARB2; Limp-2 in mice) causes collapsing focal and segmental glomerular sclerosis (FSGS) and myoclonic epilepsy in humans, but patients with no apparent kidney damage have recently been described. We now demonstrate that these patients can develop tubular proteinuria. To determine the mechanism, mice deficient in Limp-2, the murine homolog of SCARB2, were studied. Most low-molecular-weight proteins filtered by the glomerulus are removed in the proximal convoluted tubule (PCT) by megalin/cubilin-dependent receptor-mediated endocytosis. Expression of megalin and cubilin was unchanged in Limp-2(-/-) mice, however, and the initial uptake of injected Alexa Fluor 555-conjugated bovine serum albumin (Alexa-BSA) was similar to wild-type mice, indicating that megalin/cubilin-dependent, receptor-mediated endocytosis was unaffected. There was a defect in proteolysis of reabsorbed proteins in the Limp-2(-/-) mice, demonstrated by the persistence of Alexa-BSA in the PCT compared with controls. This was associated with the failure of the lysosomal protease cathepsin B to colocalize with Alexa-BSA and endogenous retinol-binding protein in kidneys from Limp-2(-/-) mice. The data suggest that tubular proteinuria in Limp-2(-/-) mice is due to failure of endosomes containing reabsorbed proteins to fuse with lysosomes in the proximal tubule of the kidney. Failure of proteolysis is a novel mechanism for tubular proteinuria.


Assuntos
Nefropatias/genética , Rim/metabolismo , Proteínas de Membrana Lisossomal/genética , Proteinúria/genética , Receptores Depuradores/genética , Animais , Imunofluorescência , Humanos , Nefropatias/metabolismo , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteínas de Membrana Lisossomal/metabolismo , Lisossomos/metabolismo , Espectrometria de Massas , Camundongos , Camundongos Knockout , Proteinúria/metabolismo , Receptores Depuradores/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
9.
Parassitologia ; 47(3-4): 353-60, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16866041

RESUMO

Lewis W. Hackett joined the staff of the International Health Board (IHB) in 1914. He was sent to Brazil in 1916, where his original responsibility was hookworm control, but he was gradually and inevitably drawn into combating other diseases. Hackett had a strong influence on public health in Brazil. In 1922 he instituted grass-roots (local) health units and programs. The next year, he negotiated with the federal government a cooperative yellow fever control program, which was described in the IHB's 1923 annual report as the "new and final campaign against yellow fever" in Brazil. Eleven offices were established in northern Brazil, where it was expected that yellow fever would quickly be eradicated. Just as the new program got underway Hackett was reassigned to Italy, where he remained until the beginning of World War II. Nonetheless, Hackett had done a classic job of developing the IHB program in Brazil, moving carefully but authoritatively from the initial focus on hookworm, to the development of a more comprehensive public health program, and then to the strategic thrust toward yellow fever.


Assuntos
Agências Internacionais/história , Cooperação Internacional/história , Febre Amarela/história , Ancilostomíase/história , Ancilostomíase/terapia , Animais , Brasil/epidemiologia , Cultura , História do Século XX , Humanos , Agências Internacionais/organização & administração , Malária/epidemiologia , Malária/história , Malária/prevenção & controle , Controle de Mosquitos/história , Estados Unidos , Febre Amarela/epidemiologia , Febre Amarela/prevenção & controle
12.
J Pediatr Gastroenterol Nutr ; 33(3): 319-25, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11593129

RESUMO

BACKGROUND: Many children with cystic fibrosis grow poorly and are malnourished. This study was undertaken to determine whether extensive anthropometry could detect early signs of malnutrition in prepubertal children with cystic fibrosis to prevent deficits in height and weight. METHODS: Height, weight, six skin folds (triceps, subscapular, supraspinale, abdominal, front thigh, and medial calf) and five girths (arm relaxed, forearm, chest, thigh, and calf) were measured in a cross-sectional study of children aged 6 to 11 years with cystic fibrosis. RESULTS: The children with cystic fibrosis were shorter and lighter for their age and gender than those in the reference groups. The mean weight and height z scores for the girls with cystic fibrosis were lower than those for the boys, significantly so for z weight ( P < 0.05). Although, the mean percent ideal body weight value of 98.6% suggested that the children with cystic fibrosis were adequately nourished, most of the measures of muscularity and adiposity of the children with cystic fibrosis were significantly lower than those of the reference group ( P < 0.05). The z scores of the anthropometric measures revealed that the deficit in muscularity of the children with cystic fibrosis was relatively much greater than the deficit in adiposity. CONCLUSIONS: The percent ideal body weight index does not seem to be an adequate measure of nutritional status in children with cystic fibrosis. Anthropometric assessments should include skin-fold and circumference measurements of numerous sites on the upper and lower body, the trunk, and the limbs to detect deterioration in nutritional status early. Early detection of deficits in nutritional status may result in the adverse effects of malnutrition on height and weight, and possibly clinical status, being prevented.


Assuntos
Transtornos da Nutrição Infantil/diagnóstico , Transtornos da Nutrição Infantil/etiologia , Fibrose Cística/complicações , Antropometria , Estatura , Peso Corporal , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Valores de Referência , Testes de Função Respiratória , Fatores Sexuais
13.
FEBS Lett ; 500(3): 163-8, 2001 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-11445078

RESUMO

The AMP-activated protein kinase (AMPK) is a heterotrimeric protein composed of a catalytic alpha subunit and two regulatory subunits, beta and gamma. The gamma subunit is essential for enzyme activity by virtue of its binding to the C-terminus of the alpha subunit and appears to play some role in the determination of AMP sensitivity. We demonstrate that a gamma1R70Q mutation causes a marked increase in AMPK activity and renders it largely AMP-independent. This activation is associated with increased phosphorylation of the alpha subunit activation loop T172. These in vitro characteristics of AMPK are also reflected in increased intracellular phosphorylation of one of its major substrates, acetyl-CoA carboxylase. These data illustrate the importance of the gamma1 subunit in the regulation of AMPK and its modulation by AMP.


Assuntos
Proteínas de Transporte , Mutagênese Sítio-Dirigida , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Subunidades Proteicas , Proteínas de Saccharomyces cerevisiae , Proteínas Quinases Ativadas por AMP , Substituição de Aminoácidos , Animais , Células COS , Linhagem Celular , Ativação Enzimática/genética , Expressão Gênica , Humanos , Isoenzimas/genética , Fosforilação , Estrutura Terciária de Proteína/genética , Alinhamento de Sequência , Relação Estrutura-Atividade , Fatores de Transcrição/genética , Transfecção , Leveduras
14.
J Biol Chem ; 276(21): 17625-8, 2001 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-11292821

RESUMO

Endothelial nitric-oxide synthase (eNOS) is an important regulatory enzyme in the cardiovascular system catalyzing the production of NO from arginine. Multiple protein kinases including Akt/PKB, cAMP-dependent protein kinase (PKA), and the AMP-activated protein kinase (AMPK) activate eNOS by phosphorylating Ser-1177 in response to various stimuli. During VEGF signaling in endothelial cells, there is a transient increase in Ser-1177 phosphorylation coupled with a decrease in Thr-495 phosphorylation that reverses over 10 min. PKC signaling in endothelial cells inhibits eNOS activity by phosphorylating Thr-495 and dephosphorylating Ser-1177 whereas PKA signaling acts in reverse by increasing phosphorylation of Ser-1177 and dephosphorylation of Thr-495 to activate eNOS. Both phosphatases PP1 and PP2A are associated with eNOS. PP1 is responsible for dephosphorylation of Thr-495 based on its specificity for this site in both eNOS and the corresponding synthetic phosphopeptide whereas PP2A is responsible for dephosphorylation of Ser-1177. Treatment of endothelial cells with calyculin selectively blocks PKA-mediated dephosphorylation of Thr-495 whereas okadaic acid selectively blocks PKC-mediated dephosphorylation of Ser-1177. These results show that regulation of eNOS activity involves coordinated signaling through Ser-1177 and Thr-495 by multiple protein kinases and phosphatases.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Endotélio Vascular/metabolismo , Óxido Nítrico Sintase/metabolismo , Proteína Quinase C/metabolismo , Animais , Bovinos , Células Cultivadas , Óxido Nítrico Sintase Tipo III , Fosforilação , Transdução de Sinais
15.
Biochem J ; 354(Pt 2): 275-83, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11171104

RESUMO

The AMP-activated protein kinase (AMPK) is a ubiquitous mammalian protein kinase important in the adaptation of cells to metabolic stress. The enzyme is a heterotrimer, consisting of a catalytic alpha subunit and regulatory beta and gamma subunits, each of which is a member of a larger isoform family. The enzyme is allosterically regulated by AMP and by phosphorylation of the alpha subunit. The beta subunit is post-translationally modified by myristoylation and multi-site phosphorylation. In the present study, we have examined the impact of post-translational modification of the beta-1 subunit on enzyme activity, heterotrimer assembly and subcellular localization, using site-directed mutagenesis and expression of subunits in mammalian cells. Removal of the myristoylation site (G2A mutant) results in a 4-fold activation of the enzyme and relocalization of the beta subunit from a particulate extranuclear distribution to a more homogenous cell distribution. Mutation of the serine-108 phosphorylation site to alanine is associated with enzyme inhibition, but no change in cell localization. In contrast, the phosphorylation site mutations, SS24, 25AA and S182A, while having no effects on enzyme activity, are associated with nuclear redistribution of the subunit. Taken together, these results indicate that both myristoylation and phosphorylation of the beta subunit of AMPK modulate enzyme activity and subunit cellular localization, increasing the complexity of AMPK regulation.


Assuntos
Complexos Multienzimáticos/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Quinases Ativadas por AMP , Animais , Células COS , Domínio Catalítico/genética , Proteínas de Fluorescência Verde , Humanos , Cinética , Proteínas Luminescentes/metabolismo , Complexos Multienzimáticos/química , Complexos Multienzimáticos/genética , Mutagênese Sítio-Dirigida , Ácido Mirístico/metabolismo , Fosforilação , Conformação Proteica , Dobramento de Proteína , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Subunidades Proteicas , Proteínas Recombinantes de Fusão/metabolismo , Relação Estrutura-Atividade
16.
Soc Secur Bull ; 64(1): 84-114, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-12428519

RESUMO

The Supplemental Security Income (SSI) and Aid to Families with Dependent Children (AFDC) programs serve populations with similar characteristics. SSI serves adults and children with disabilities who are in low-income families, and AFDC serves low-income families with children. Because of that overlap, policy changes in one program can affect the other. In 1996, Congress enacted the Personal Responsibility and Work Opportunity Reconciliation Act, which transformed AFDC into the Temporary Assistance for Needy Families (TANF) program. Many people have expected that implementing that welfare reform legislation would eventually increase SSI participation, for two reasons. First, TANF includes new work requirements and time limits that induce more AFDC/TANF recipients with disabilities to obtain SSI benefits. Second, the change in the funding mechanism--from open-ended funding on a matching basis for AFDC to cash assistance block grants for TANF--gives states a stronger incentive to shift welfare recipients to SSI. This article examines the interaction between the SSI and AFDC programs in the prereform period (1990 to 1996) and discusses the potential implications of welfare reform on that interaction. Using matched data from the Survey of Income and Program Participation and Social Security Administration (SSA) records, our analysis focuses on how the interaction of those programs affects young women (aged 18 to 40) and children (aged 0 to 17). We find a very strong link between AFDC and SSI for young women and children. Significant portions of young female and child SSI beneficiaries in the 1990-1993 period were in AFDC families or had received AFDC in the past. In addition, a substantial share of young women and children who received AFDC during that period eventually entered SSI. Because the SSI program is now serving a much larger population of families with young women and children than in the past, SSA might need to develop policies to better serve that group. The findings also suggest that the prereform period is a poor baseline against which to measure the impact of TANF, primarily because of the instability in programs and policies.


Assuntos
Ajuda a Famílias com Filhos Dependentes/estatística & dados numéricos , Política Pública , Previdência Social/estatística & dados numéricos , Adolescente , Adulto , Ajuda a Famílias com Filhos Dependentes/organização & administração , Criança , Pré-Escolar , Tomada de Decisões , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Modelos Econométricos , Análise Multivariada , Modelos de Riscos Proporcionais , Previdência Social/organização & administração , Estados Unidos
18.
Congest Heart Fail ; 6(6): 333-336, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-12189340

RESUMO

The use of a multisite transvenous pacemaker in a patient with refractory heart failure who experienced short-term symptomatic improvement is described. The improvement in heart failure symptoms was most likely related to resynchronization of atrioventricular and interventricular asynchrony. Large, multicenter, randomized trials of this technology are being performed to evaluate the importance of this therapeutic modality in the treatment of heart failure. (c)2000 by CHF, Inc.

19.
Congest Heart Fail ; 6(3): 164-166, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-12029185

RESUMO

The authors describe the use of milrinone as a bridge to beta blockade in a patient with severe heart failure. This case is clinically important because in patients with severe heart failure phosphodiesterase inhibitors, unlike beta agonists, will retain their positive inotropic and vasodilator effects in the presence of beta blockade and, in addition, these agents will attenuate the negative inotropic side effects of beta blockers. Conversely, a beta blocker associated with a phosphodiesterase inhibitor will protect against myocyte loss and arrhythmias, may prevent sudden death, and will improve long-term symptoms and exercise tolerance. This combination is being investigated in a large, multicenter, double-blind, randomized trial of intravenous milrinone vs. placebo as a therapeutic tool to allow the initiation of carvedilol orally in patients hospitalized with class III/IV heart failure. (c)2000 by CHF, Inc.

20.
Congest Heart Fail ; 6(2): 115-117, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-12029197

RESUMO

The authors describe the use of spironolactone, an aldosterone receptor blocker, in a patient with heart failure refractory to conventional therapy. The clinical importance of this case is that not only does spironolactone improve symptoms, but its use also improves survival in patients with severe heart failure. Clinicians should be aware that this therapy has to be added to the medical armamentarium for patients with severe heart failure. In addition, it is important to point out that the use of the aldosterone receptor blockers and their beneficial effects in morbidity and mortality in heart failure has helped to understand more clearly the relationship between aldosterone and its importance in the pathophysiology of heart failure. (c)2000 by CHF, Inc.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA