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1.
J Vasc Interv Radiol ; 30(8): 1244-1250.e1, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31349978

RESUMO

PURPOSE: This randomized, placebo-controlled, double-blind, dose-escalation acute ischemic stroke trial was designed to demonstrate maximum tolerated dose, characterize adverse events (AEs), and explore clinical outcomes when intravenous dodecafluoropentane emulsion (DDFPe) was used as neuroprotection. METHODS: Acute ischemic stroke patients (n = 24) with National Institutes of Health Stroke Scale (NIHSS) score of 2-20 were randomized to either 3 doses of intravenous DDFPe or placebo, 1 every 90 minutes, starting within 12 hours of symptom onset. Doses were given without affecting standard stroke care. Each of the 3 dose cohorts included 8 patients, with 2 receiving placebo and 6 receiving DDFPe. Primary outcomes were serious adverse events (SAEs), AEs, NIHSS score, and modified Rankin Score (mRS). RESULTS: No dose-limiting toxicities were encountered, and no maximum tolerated dose was defined. One unrelated delayed death occurred in a DDFPe patient, and another occurred in the placebo group. Group SAEs and AEs were similar in incidence and severity. Early initiation of DDFPe treatment resulted in better NIHSS score response than late initiation (P = .03). Thirty- and 90-day mRS after high-dose therapy suggested clinical improvement (P = .01 and P = .03, respectively). However, the significance of differences in clinical outcomes was limited by small patient numbers and differences in stroke severity between cohorts. CONCLUSIONS: Intravenous DDFPe appears to be safe at all doses tested. Clinical improvements in NIHSS score and mRS were significant but compromised by small sample size.


Assuntos
Isquemia Encefálica/tratamento farmacológico , Fluorocarbonos/administração & dosagem , Fármacos Neuroprotetores/administração & dosagem , Acidente Vascular Cerebral/terapia , Administração Intravenosa , Arkansas , Isquemia Encefálica/diagnóstico , Isquemia Encefálica/fisiopatologia , Avaliação da Deficiência , Método Duplo-Cego , Esquema de Medicação , Feminino , Fluorocarbonos/efeitos adversos , Humanos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Fármacos Neuroprotetores/efeitos adversos , Recuperação de Função Fisiológica , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/fisiopatologia , Fatores de Tempo , Resultado do Tratamento
3.
Europace ; 15(6): 827-34, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23512155

RESUMO

AIMS: Differentiation between supraventricular tachycardia (SVT) and ventricular tachycardia (VT) remains a substantial clinical challenge in patients with single-chamber implantable cardioverter-defibrillators (ICDs) due to absence of visible P waves. Innovative optimization of intrathoracic electrogram (EGM) configuration will facilitate P-wave detection and rhythm differentiation during tachycardia. METHODS AND RESULTS: Innovative optimization of EGM configuration was originally performed to improve patient care. In this retrospective cohort study, we examined our database for records of 140 consecutive patients undergoing single-chamber ICD implantation. During the follow-ups of 61 included patients with optimized EGM configuration, 27 patients were identified to have VT and/or SVT. EGMs in the Can (generator) to superior vena cava (Can-SVC) configuration were compared with those conventionally from the Can to right ventricular coil (Can-RV coil) source in the same patients. In Can-SVC EGMs, the ratio of P/QRS amplitude was 14-fold higher (0.57 ± 0.08 vs. 0.04 ± 0.00, P < 0.001) compared with those in Can-RV coil EGMs during sinus rhythm. With Can-SVC configuration, the odds of atrioventricular dissociation detection in patients with VT was increased 15-fold (61.9% vs. 9.5% with Can-RV coil; odds ratio, 15.4; 95% confidence interval, 2.8 to 84.7; P = 0.0009). In patients with SVT, P-waves or retrograde P-waves were markedly more identifiable in Can-SVC configuration compared with Can-RV coil (odds ratio, 40; 95% confidence interval, 3.6 to 447.1; P = 0.0010). CONCLUSION: P-wave recognition by optimizing EGM configuration provides a novel diagnostic tool for differentiation between VT and SVT in single-chamber ICDs. A potential discrimination algorithm would provide a cost-effective approach to improving the qualitative outcomes.


Assuntos
Desfibriladores Implantáveis , Eletrocardiografia/métodos , Taquicardia Supraventricular/diagnóstico , Taquicardia Supraventricular/prevenção & controle , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/prevenção & controle , Terapia Assistida por Computador/métodos , Algoritmos , Diagnóstico por Computador/métodos , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade , Resultado do Tratamento
4.
Stroke ; 39(3): 1042-8, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18258828

RESUMO

BACKGROUND AND PURPOSE: Statins are widely used to reduce the risk of stroke in patients with coronary artery disease (CAD), but less so in patients without CAD. We reviewed recent trials for new evidence for the reduction in risk of stroke. SUMMARY OF REVIEW: In patients with CAD, moderate-intensity statin treatment has been associated with reductions in risk of stroke, with no increase in hemorrhagic stroke. Additionally, in the TNT trial, intensive lipid lowering provided further stroke risk reduction compared with moderate lipid lowering in patients with stable CAD. Evidence is now available that statin therapy also reduces stroke risk in patients without CAD but at high cardiovascular risk, or with diabetes mellitus. The SPARCL trial showed that intensive statin therapy started within 6 months after a cerebrovascular event significantly reduced stroke risk and stroke severity. Low cholesterol levels have been associated with increased risk of hemorrhagic stroke, but although an increased risk of hemorrhagic stroke was observed in patients with prior hemorrhagic stroke in SPARCL, this was not related to low-density lipoprotein cholesterol levels. Clinical trials have recruited few patients with both coronary and cerebrovascular disease, but these patients are also expected to experience significant cardiovascular benefit with statin therapy. CONCLUSIONS: Trial data show that statins reduce the risk of stroke, in addition to providing cardiovascular benefits. Consequently, physicians should consider statin therapy in all patients at high risk of stroke.


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Acidente Vascular Cerebral/prevenção & controle , Hemorragia Cerebral/complicações , Transtornos Cerebrovasculares/complicações , Transtornos Cerebrovasculares/tratamento farmacológico , Colesterol/sangue , Doença da Artéria Coronariana/complicações , Doença da Artéria Coronariana/tratamento farmacológico , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Prevenção Secundária , Acidente Vascular Cerebral/induzido quimicamente , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/etiologia
5.
J Pharmacol Exp Ther ; 325(1): 37-46, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18184831

RESUMO

Calcium influx through long-lasting ("L-type") Ca(2+) channels (Ca(V)) drives excitation-contraction in the normal heart. Dysregulation of this process contributes to Ca(2+) overload, and interventions that reduce expression of the pore-forming alpha(1) subunit may alleviate cytosolic Ca(2+) excess. As a molecular approach to disrupt the assembly of Ca(V)1.2 (alpha(1C)) channels at the cell membrane, we targeted the Ca(2+) channel beta(2) subunit, an intracellular chaperone that interacts with alpha(1C) via its beta interaction domain (BID) to promote Ca(V)1.2 channel expression. Recombinant adenovirus expressing either the full beta(2) subunit (Full-beta(2)) or truncated beta(2) subunit constructs lacking either the C terminus, N terminus, or both (N-BID, C-BID, and BID, respectively) fused to green fluorescent protein were developed as potential decoys and overexpressed in HL-1 cells. Fluorescence microscopy revealed that the localization of Full-beta(2) at the surface membrane was associated with increased Ca(2+) current mainly attributed to Ca(V)1.2 channels. In contrast, truncated N-BID and C-BID constructs showed punctate intracellular expression, and BID showed a diffuse cytosolic distribution. Total expression of the alpha(1C) protein of Ca(V)1.2 channels was similar between groups, but HL-1 cells overexpressing C-BID and BID exhibited reduced Ca(2+) current. C-BID and BID also attenuated Ca(2+) current associated with another L-type Ca(2+) channel, Ca(V)1.3, but they did not reduce transient Ca(2+) currents attributed to Ca(V)3 channels. These results suggest that beta(2) subunit mutants lacking the N terminus may preferentially disrupt the proper localization of L-type Ca(2+) channels in the cell membrane. Cardiac-specific delivery of these decoy molecules in vivo may represent a gene-based treatment for pathologies involving Ca(2+) overload.


Assuntos
Canais de Cálcio Tipo L/efeitos dos fármacos , Desenho de Fármacos , Terapia Genética/métodos , Mimetismo Molecular , Mutação , Miocárdio/química , Animais , Cálcio/metabolismo , Canais de Cálcio Tipo L/genética , Linhagem Celular , DNA Complementar/genética , Regulação para Baixo/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Humanos , Miocárdio/citologia , Engenharia de Proteínas/métodos , Subunidades Proteicas/genética , Subunidades Proteicas/uso terapêutico , Ratos
6.
Trans Am Clin Climatol Assoc ; 119: 171-82; discussion 182-3, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18596857

RESUMO

Modifying ion channel expression and function in the heart and vasculature are potentially useful, novel approaches to managing cardiac hypertrophy, atrial fibrillation and hypertension. Calcium channels play a pivotal role in the heart and vasculature in controlling muscle contraction as well as other aspects of calcium-dependent signaling. The present investigation reports development of mutated L-type calcium channel beta subunits that are delivered by an adenoviral vector to vascular smooth muscle tissue. Wild type subunits serve a chaperone function for the pore-forming alpha(1C) subunit of the calcium channel, localize to the cell membrane and enhance calcium current. Conversely, mutated subunits function as dominant negative, defective chaperone molecules that disrupt targeting to the cell membrane and decrease calcium current. The dominant negative genes can be delivered in vitro and ex vivo, and have the potential to decrease arterial tone and lower blood pressure in vivo.


Assuntos
Doenças Cardiovasculares/genética , Doenças Cardiovasculares/terapia , Terapia Genética/métodos , Canais Iônicos/genética , Animais , Canais de Cálcio Tipo L/química , Canais de Cálcio Tipo L/genética , Canais de Cálcio Tipo L/fisiologia , Doenças Cardiovasculares/fisiopatologia , Células Cultivadas , Vetores Genéticos , Hipertensão/genética , Hipertensão/fisiopatologia , Hipertensão/terapia , Canais Iônicos/fisiologia , Artérias Mesentéricas/citologia , Artérias Mesentéricas/fisiologia , Miócitos de Músculo Liso/fisiologia , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo
7.
Acad Med ; 93(4): 565-573, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28991849

RESUMO

The U.S. physician-scientist (PS) workforce is invaluable to the nation's biomedical research effort. It is through biomedical research that certain diseases have been eliminated, cures for others have been discovered, and medical procedures and therapies that save lives have been developed. Yet, the U.S. PS workforce has both declined and aged over the last several years. The resulting decreased inflow and outflow to the PS pipeline renders the system vulnerable to collapsing suddenly as the senior workforce retires. In November 2015, the Alliance for Academic Internal Medicine hosted a consensus conference on the PS workforce to address issues impacting academic medical schools, with input from early-career PSs based on their individual experiences and concerns. One of the goals of the conference was to identify current impediments in attracting and supporting PSs and to develop a new set of recommendations for sustaining the PS workforce in 2016 and beyond. This Perspective reports on the opportunities and factors identified at the conference and presents five recommendations designed to increase entry into the PS pipeline and nine recommendations designed to decrease attrition from the PS workflow.


Assuntos
Pesquisa Biomédica , Médicos/provisão & distribuição , Pesquisadores/provisão & distribuição , Recursos Humanos , Conferências de Consenso como Assunto , Estados Unidos
8.
Circ Res ; 97(10): 1009-17, 2005 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-16210547

RESUMO

Increases in Ca2+ influx through the L-type Ca2+ channel (LTCC, Cav1.2) augment sarcoplasmic reticulum (SR) Ca2+ loading and the amplitude of the cytosolic Ca2+ transient to enhance cardiac myocyte contractility. Our hypothesis is that persistent increases in Ca2+ influx through the LTCC cause apoptosis if the excessive influx results in SR Ca2+ overload. Feline ventricular myocytes (VMs) in primary culture were infected with either an adenovirus (Ad) containing a rat Cav1.2 beta2a subunit-green fluorescent protein (GFP) fusion gene (Adbeta2a) to increase Ca2+ influx or with AdGFP as a control. Significantly fewer beta2a-VMs (21.4+/-5.6%) than GFP-VMs (99.6+/-1.7%) were viable at 96 hours. A fraction of beta2a-VMs (20.8+/-1.8%) contracted spontaneously (SC-beta2a-VMs), and viability was significantly correlated with the percentage of SC-beta2a-VMs. Higher percentages of apoptotic nuclei, DNA laddering, and cytochrome C release were detected in beta2a-VMs. This apoptosis was prevented with pancaspase or caspase-3 or caspase-9 inhibitors. L-type calcium current (I(Ca-L)) density was greater in beta2a-VMs (23.4+/-2.8 pA/pF) than in GFP-VMs (7.6+/-1.6 pA/pF). SC-beta2a-VMs had higher diastolic intracellular Ca2+ (Indo-1 ratio: 1.1+/-0.1 versus 0.7+/-0.03, P<0.05) and systolic Ca2+ transients (1.89+/-0.27 versus 0.80+/-0.08) than GFP-VMs. Inhibitors of Ca2+ influx, SR Ca2+ uptake and release, mitochondrial Ca2+ uptake, mitochondrial permeation transition pore, calpain, and Bcl-2-associated X protein protected beta2a-VMs from apoptosis. These results show that persistent increases in Ca2+ influx through the I(Ca-L) enhance contractility but lead to apoptosis through a mitochondrial death pathway if SR Ca2+ overload is induced.


Assuntos
Apoptose , Canais de Cálcio Tipo L/fisiologia , Cálcio/metabolismo , Mitocôndrias Cardíacas/fisiologia , Miócitos Cardíacos/patologia , Retículo Sarcoplasmático/metabolismo , Animais , Canais de Cálcio Tipo L/análise , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Proteínas Quinases Dependentes de Cálcio-Calmodulina/fisiologia , Caspase 8 , Caspases/fisiologia , Gatos , Células Cultivadas , Ventrículos do Coração , Contração Miocárdica , Miócitos Cardíacos/metabolismo , Fosforilação , Subunidades Proteicas , Ratos , Proteína Killer-Antagonista Homóloga a bcl-2/fisiologia , Proteína X Associada a bcl-2/fisiologia
9.
Acad Med ; 92(11): 1564-1568, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28471777

RESUMO

Recruiting faculty leaders to work in colleges of medicine is a ubiquitous, time-consuming, costly activity. Little quantitative information is available about contemporary leadership recruiting processes and outcomes. In this article, the authors examine current recruiting methods and outcomes in colleges of medicine and compare academic search approaches with the approaches often employed in intellectual-capital-rich industries.In 2015, the authors surveyed chairs of internal medicine at U.S. medical schools regarding their recruiting practices and outcomes-specifically their selection methods, the duration of searches, the recruitment of women and minorities underrepresented in medicine (URM), and their satisfaction with search outcomes.The authors found that department chairs were extensively engaged in numerous searches for leaders. The recruitment process most commonly required 7 to 12 months from initiation to signed contract. Interestingly, longer searches (19+ months) were much more frequently associated with a recruitment outcome that chairs viewed as unsatisfactory or very unsatisfactory. Most leadership searches produced very few women and URM finalists. The biggest perceived hurdles to successful recruitment were the need to relocate the candidate and family and the shortage of good candidates.The process of recruiting leaders in academic medicine has changed little in more than 25 years. Process improvement is important and should entail carefully structured search processes, including both an overhaul of search committees and further emphasis on leadership development within the college of medicine. The authors propose specific steps to enhance recruitment of members of URM groups and women to leadership positions in academic medicine.


Assuntos
Docentes de Medicina , Medicina Interna , Liderança , Seleção de Pessoal , Humanos , Grupos Minoritários , Faculdades de Medicina , Inquéritos e Questionários , Estados Unidos , Mulheres
10.
J Am Heart Assoc ; 6(5)2017 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-28522678

RESUMO

BACKGROUND: Cigarette smoking plays a major role in cardiovascular diseases. The acute effects of cigarette smoking produce central nervous system-mediated activation of the sympathetic nervous system. The overactive sympathetic nervous system stimulates the secretion of serotonin (5-HT) and catecholamine into blood at supraphysiological levels. The correlation between these pathological conditions induced by smoking and the increased risk of thrombosis has not been thoroughly investigated. The goal of our study was to explore cigarette smoking-associated changes in platelet biology mediated by elevated 5-HT and catecholamine levels in blood plasma. METHODS AND RESULTS: Using blood samples collected from healthy nonsmokers and smokers (15 minutes after smoking), we determined that cigarette smoking increased the plasma 5-HT/catecholamine concentration by several fold and the percent aggregation of platelets 2-fold. Liquid chromatography-tandem mass spectrometry analysis of proteins eluted from platelet plasma membranes of smokers and nonsmokers demonstrated that GTPase-activating proteins and proteins participating in the actin cytoskeletal network were differentially and significantly elevated in smokers' platelet membranes compared with those of nonsmokers. Interestingly, Matrix-assisted laser desorption/ionization-mass spectrometry analyses of the glycans eluted from platelet plasma membranes of the smokers demonstrated that the level and structures of glycans are different from the nonsmokers' platelet surface glycans. Pharmacological blockade of 5-HT or catecholamine receptors counteracted the 5-HT/catecholamine-mediated aggregation and altered the level and composition of glycan on platelet surfaces. CONCLUSIONS: Based on our findings, we propose that smoking-associated 5-HT/catecholamine signaling accelerates the trafficking dynamics of platelets, and this remodels the surface proteins and glycans and predisposes platelets to hyperactive levels. Smokers' platelets also had correspondingly higher resting concentrations of intracellular calcium and transglutaminase activity. These findings suggest a link among smoking, platelet 5-HT, catecholamine signaling, and their downstream effectors-including phospholipase C and inositol-1,4,5-triphosphate pathways-resulting in an increased tonic level of platelet activation in smokers.


Assuntos
Plaquetas/metabolismo , Membrana Celular/metabolismo , Epinefrina/sangue , Ativação Plaquetária , Serotonina/sangue , Transdução de Sinais , Fumar/sangue , Antagonistas Adrenérgicos beta/farmacologia , Adulto , Plaquetas/efeitos dos fármacos , Cálcio/sangue , Estudos de Casos e Controles , Membrana Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Humanos , Masculino , Ativação Plaquetária/efeitos dos fármacos , Agregação Plaquetária , Inibidores da Agregação Plaquetária/farmacologia , Polissacarídeos/sangue , Transporte Proteico , Antagonistas do Receptor 5-HT2 de Serotonina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Fumar/efeitos adversos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em Tandem , Fatores de Tempo , Transglutaminases/sangue , Regulação para Cima
11.
Diabetes ; 54(2): 540-5, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15677513

RESUMO

Apoptosis plays a critical role in normal vascular development and atherosclerosis. To test the hypothesis that diabetic vasculopathy may be due in part to altered apoptosis pathways, we investigated the effects of high glucose treatment on serum withdrawal-induced apoptosis, expression of Bcl-2 family members, and inhibitor of apoptosis protein (IAP)-1 in vascular smooth muscle cells (VSMCs). Treatment with a high concentration of glucose (22 mmol/l) significantly attenuated apoptosis in response to serum withdrawal in cultured rat VSMCs compared with cells treated with a normal glucose concentration (5.5 mmol/l). This attenuation was accompanied by a significant decrease in the caspase-3 activity in comparison with the normal glucose group. Furthermore, exposure of VSMCs to high glucose markedly increased the abundance of Bcl-2 and Bcl-xl mRNAs compared with treatment with normal glucose, while expression of bax and IAP-1 mRNA remained unchanged. Our results suggest that high glucose suppresses serum withdrawal-induced apoptosis in VSMCs by upregulating expression of Bcl-2 and Bcl-xl, suggesting that enhanced expression of antiapoptotic proteins may play an important role in the development of macrovascular complications in diabetes.


Assuntos
Apoptose/efeitos dos fármacos , Glucose/farmacologia , Músculo Liso Vascular/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Animais , Aorta , Sequência de Bases , Técnicas de Cultura de Células , Meios de Cultura Livres de Soro , Primers do DNA , Marcação In Situ das Extremidades Cortadas , Proteínas Inibidoras de Apoptose , Manitol/farmacologia , Músculo Liso Vascular/efeitos dos fármacos , Proteínas/efeitos dos fármacos , Proteínas/genética , RNA Mensageiro/genética , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteína bcl-X
12.
Vascul Pharmacol ; 44(3): 131-42, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16427812

RESUMO

Long-lasting Ca(2+) (Ca(L)) channels of the Ca(v)1.2 gene family are heteromultimeric structures that are minimally composed of a pore-forming alpha(1C) subunit and regulatory beta and alpha(2)delta subunits in vascular smooth muscle cells. The Ca(L) channels are the primary pathways for voltage-gated Ca(2+) influx that trigger excitation-contraction coupling in small resistance vessels. Notably, vascular smooth muscle cells of hypertensive rats show an increased expression of Ca(L) channel alpha(1C) subunits, which is associated with elevated Ca(2+) influx and the development of abnormal arterial tone. Indeed, blood pressure per se appears to promote Ca(L) channel expression in small arteries, and even short-term rises in pressure may alter channel expression. Membrane depolarization has been shown to be one stimulus associated with elevated blood pressure that promotes Ca(L) channel expression at the plasma membrane. Future studies to define the molecular processes that regulate Ca(L) channel expression in vascular smooth muscle cells will provide a rational basis for designing antihypertensive therapies to normalize Ca(L) channel expression and the development of anomalous vascular tone in hypertensive pathologies.


Assuntos
Canais de Cálcio Tipo L/metabolismo , Hipertensão/metabolismo , Músculo Liso Vascular/fisiologia , Animais , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Canais de Cálcio Tipo L/química , Canais de Cálcio Tipo L/genética , Regulação da Expressão Gênica , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/fisiopatologia , Ativação do Canal Iônico , Potenciais da Membrana , Músculo Liso Vascular/efeitos dos fármacos , Conformação Proteica
13.
Biochim Biophys Acta ; 1577(3): 401-11, 2002 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-12359330

RESUMO

Expression of L-type calcium channels in cardiac myocytes and vascular smooth muscle cells (VSMC) critically regulates the contractile state of these cells. In order to discover the elements in the promoter region of the Ca(v)1.2 gene encoding the vascular/cardiac calcium channel alpha(1C) subunit that are important for the basal gene expression, approximately 2 kb of the 5'-flanking sequence of the Ca(v)1.2 gene has been cloned in our lab. In this study, using various lengths of the 5'-flanking DNA fused with a luciferase gene as a reporter, we have defined a 493-bp fragment of the cis-regulatory DNA which carries the majority of promoter activity in pulmonary artery smooth muscle (PAC1) cells. DNase I footprinting analysis of this 493-bp DNA using nuclear extracts from PAC1 cells revealed a 27-bp DNA sequence that contains a c-Ets like motif (CAGGATGC). Mutation of the Ets-like site and the respective flanking sequence within the DNase I footprinting protection region induced a marked change in the promoter activity in PAC1 cells. Electrophoretic mobility shift assays (EMSA) confirmed the presence of specific binding factor(s) in PAC1 cells' nuclear extracts for this 27-bp DNA. Competition studies with the wild-type and mutated DNA fragments established the importance of the 27 bp DNA sequence for high-affinity binding of the nuclear proteins to the promoter. We conclude that there is a 27 bp region in the promoter of the Ca(v)1.2 gene to which nuclear proteins from VSMC bind and strongly regulate the basal promoter activity.


Assuntos
Canais de Cálcio Tipo L/genética , Músculo Liso Vascular/metabolismo , Regiões Promotoras Genéticas/fisiologia , Animais , Sequência de Bases , Sítios de Ligação , Canais de Cálcio Tipo L/biossíntese , Linhagem Celular , Pegada de DNA , Ensaio de Desvio de Mobilidade Eletroforética , Dados de Sequência Molecular , Mutação , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-ets , Artéria Pulmonar , Ratos , Sequências Reguladoras de Ácido Nucleico , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica
15.
Eur J Endocrinol ; 152(3): 479-83, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15757866

RESUMO

Variation between the sexes in cardiac function have been established. The extent to which sex hormones are responsible for these differences is unclear. The current study was designed to determine whether testosterone acts acutely to enhance contractility of cultured rat ventricular myocytes. Following a 24-h treatment with testosterone (1 microM), isolated rat ventricular myocytes display a 21% increase (P < 0.01) in peak shortening and an 18% decrease (P < 0.02) in time to peak shortening. In accordance with this change, testosterone treatment produced an 18% decline (P < 0.002) in the time to relengthening when compared to vehicle-treated controls. These results provide the first evidence that short-term androgen exposure acts directly to stimulate contractility of isolated rat ventricular myocytes and thus may play a role in regulating cardiac performance in males and thereby contribute to sex differences in cardiac function.


Assuntos
Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/fisiologia , Testosterona/farmacologia , Função Ventricular/efeitos dos fármacos , Animais , Separação Celular , Células Cultivadas , Masculino , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Androgênicos/metabolismo , Propionato de Testosterona/farmacologia , Fatores de Tempo
16.
Am J Health Syst Pharm ; 59(21 Suppl 7): S15-26, 2002 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-12434711

RESUMO

The early use of glycoprotein (GP) IIb/IIIa-receptor inhibitors in patients with non-ST-segment-elevation (NSTE) acute coronary syndromes (ACSs) is discussed. Unstable angina and NSTE myocardial infarction, collectively known as NSTE ACSs, are among the leading causes of morbidity and mortality in the United States. Updated guidelines from the American College of Cardiology and the American Heart Association for the management of NSTE ACSs strongly recommend that patients with intermediate- to high-risk features (e.g., ST-segment depression, elevated cardiac markers, and recurrent ischemia) be managed with an early invasive or other aggressive strategy (diagnostic angiography within 48 hours and, if warranted, percutaneous or surgical revascularization) and immediate treatment with a GP IIb/IIIa-receptor inhibitor. In low-risk patients, either an early invasive or an early conservative strategy (diagnostic angiography only for recurrent or refractory ischemia or a positive stress test result) is appropriate. For patients managed with an early conservative approach, the guidelines recommend GP IIb/IIIa-receptor inhibitor therapy with eptifibatide or tirofiban hydrochloride, especially in high-risk patients. Abciximab should not be used in patients in whom percutaneous coronary intervention is not planned. Greater implementation of the recommendations concerning the early use of GP IIb/IIIa-receptor inhibitors may result in reduced mortality rates. A large body of clinical evidence supports the updated ACC and AHA recommendations for managing patients with NSTE ACSs.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Doença das Coronárias/tratamento farmacológico , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Peptídeos/uso terapêutico , Inibidores da Agregação Plaquetária/uso terapêutico , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Abciximab , Doença Aguda , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/efeitos adversos , Ensaios Clínicos como Assunto , Doença das Coronárias/mortalidade , Doença das Coronárias/fisiopatologia , Eptifibatida , Hemorragia/induzido quimicamente , Humanos , Fragmentos Fab das Imunoglobulinas/administração & dosagem , Fragmentos Fab das Imunoglobulinas/efeitos adversos , Peptídeos/administração & dosagem , Peptídeos/efeitos adversos , Inibidores da Agregação Plaquetária/administração & dosagem , Inibidores da Agregação Plaquetária/efeitos adversos
17.
Vasc Health Risk Manag ; 9: 187-93, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23662064

RESUMO

BACKGROUND: A dual antiplatelet regimen has been shown to reduce the risk of major adverse cardiovascular events after percutaneous coronary intervention. However, there is little information available on inhibition of platelet aggregation in patients with a prior coronary stent presenting with chest pain. This study evaluated the prevalence of hyporesponsiveness to clopidogrel and factors associated with this in patients presenting to our emergency department with chest pain who had previously undergone coronary stent placement and were prescribed dual antiplatelet therapy. METHODS: Responsiveness to clopidogrel was evaluated in a cohort of 533 consecutive stented patients presenting to the emergency department with chest pain. P2Y12 reaction units (PRU) and percent P2Y12 inhibition with clopidogrel were measured in all patients. Of 533 patients, 221 (41.6%) had PRU ≥ 230. A multivariate logistic regression model was used to determine the relationship between hyporesponsiveness to clopidogrel (defined as PRU ≥ 230) and several potential risk factors, ie, gender, age, race, type 1 or type 2 diabetes, hypertension, smoking, chronic renal failure, and obesity. RESULTS: There was a greater risk of hyporesponsiveness in African Americans than in non-African American patients (adjusted odds ratio [OR] = 2.165), in patients with type 2 diabetes than in those without (adjusted OR = 2.109), and in women than in men (adjusted OR = 1.813), as well as a greater risk of hyporesponsiveness with increasing age (adjusted OR = 1.167 per decade). CONCLUSION: There was a high prevalence of hyporesponsiveness to clopidogrel in patients presenting with chest pain and a prior coronary stent. Non-insulin-dependent diabetes mellitus and African American race were the strongest predictors of hyporesponsiveness to clopidogrel, followed by gender and age.


Assuntos
Plaquetas/efeitos dos fármacos , Dor no Peito/etiologia , Serviço Hospitalar de Emergência , Inibidores da Agregação Plaquetária/uso terapêutico , Testes de Função Plaquetária , Antagonistas do Receptor Purinérgico P2Y/uso terapêutico , Ticlopidina/análogos & derivados , Negro ou Afro-Americano , Fatores Etários , Idoso , Plaquetas/metabolismo , Dor no Peito/sangue , Dor no Peito/etnologia , Clopidogrel , Diabetes Mellitus Tipo 2/complicações , Resistência a Medicamentos , Quimioterapia Combinada , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Intervenção Coronária Percutânea/efeitos adversos , Intervenção Coronária Percutânea/instrumentação , Inibidores da Agregação Plaquetária/efeitos adversos , Valor Preditivo dos Testes , Estudos Prospectivos , Antagonistas do Receptor Purinérgico P2Y/efeitos adversos , Receptores Purinérgicos P2Y12/sangue , Receptores Purinérgicos P2Y12/efeitos dos fármacos , Medição de Risco , Fatores de Risco , Fatores Sexuais , Stents , Ticlopidina/efeitos adversos , Ticlopidina/uso terapêutico , Resultado do Tratamento
19.
Vasc Health Risk Manag ; 8: 65-75, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22371653

RESUMO

The substantial reduction in ischemic events provided by the dual antiplatelet regimen with aspirin and clopidogrel is well documented in patients with acute coronary syndrome and patients undergoing percutaneous coronary intervention. Recently the variable response to the antiplatelet agents has received considerable attention after several "boxed warnings" on clopidogrel. This led to intense controversy on pharmacokinetic, pharmacodynamic, and pharmacogenomic issues of antiplatelet drugs, especially clopidogrel. Research use of platelet function testing has been successfully validated in identifying new antiplatelet drugs like prasugrel and ticagrelor. These platelet function assays are no longer regarded just as a laboratory phenomenon but rather as tools that have been shown to predict mortality in several clinical trials. It is believed that suboptimal response to an antiplatelet regimen (pharmacodynamic effect) may be associated with cardiovascular, cerebrovascular, and peripheral arterial events. There has been intense controversy about this variable response of antiplatelet drugs and the role of platelet function testing to guide antiplatelet therapy. While the importance of routine platelet function testing may be uncertain, it may be useful in high-risk patients such as those with diabetes mellitus, diffuse three vessels coronary artery disease, left main stenosis, diffuse atherosclerotic disease, and those with chronic renal failure undergoing percutaneous coronary intervention. It could also be useful in patients with suspected pharmacodynamic interaction with other drugs to assure the adequacy of platelet inhibition. While we wait for definitive trials, a predictive prognostic algorithm is necessary to individualize antiplatelet therapy with P2Y12 inhibitors based on platelet function assays and genetic testing.


Assuntos
Síndrome Coronariana Aguda/tratamento farmacológico , Angioplastia Coronária com Balão , Plaquetas/efeitos dos fármacos , Doença da Artéria Coronariana/terapia , Inibidores da Agregação Plaquetária/uso terapêutico , Testes de Função Plaquetária , Antagonistas do Receptor Purinérgico P2Y/uso terapêutico , Síndrome Coronariana Aguda/sangue , Algoritmos , Angioplastia Coronária com Balão/efeitos adversos , Angioplastia Coronária com Balão/instrumentação , Animais , Doença da Artéria Coronariana/sangue , Técnicas de Apoio para a Decisão , Monitoramento de Medicamentos , Quimioterapia Combinada , Medicina Baseada em Evidências , Humanos , Inibidores da Agregação Plaquetária/efeitos adversos , Inibidores da Agregação Plaquetária/farmacocinética , Valor Preditivo dos Testes , Antagonistas do Receptor Purinérgico P2Y/efeitos adversos , Antagonistas do Receptor Purinérgico P2Y/farmacocinética , Medição de Risco , Fatores de Risco , Stents , Resultado do Tratamento
20.
J Am Coll Cardiol ; 56(9): 683-91, 2010 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-20723798

RESUMO

The decline in stroke incidence and mortality in the U.S. over the past 20 years is reaching a plateau, and the number of strokes may actually start to increase as the population ages. However, recent clinical trials have demonstrated that there are numerous opportunities to improve stroke prevention strategies and also opportunities to effectively intervene in and treat acute strokes. For patients with diabetes and for those with prior strokes or transient ischemic attacks, it has become evident that aggressive low-density lipoprotein lowering with statin medications will decrease the risk for total and fatal strokes. Optimal anticoagulation and antiplatelet therapy for primary and secondary stroke prevention in atrial fibrillation is being carefully defined. With numerous novel factor Xa and direct thrombin inhibitor drugs completing phase III clinical trials, it is likely that additional oral anticoagulant drugs will be clinically available for stroke prevention soon. Additionally, a major clinical trial is nearing completion that may resolve the role of carotid stenting and carotid endarterectomy in primary and secondary stroke prevention. There are recent notable advances in the acute treatment of stroke. It is likely that the time window for thrombolysis for appropriate patients with strokes will be increased from 3 to 4.5 h, permitting the inclusion of more patients in this treatment approach. There is ongoing investigation of intra-arterial thrombolysis and of acute intra-arterial thrombus extraction for treatment of selected patients with strokes. Unlike the progress in treatment of ischemic strokes, treatment of hemorrhagic stroke is progressing more slowly.


Assuntos
Acidente Vascular Cerebral/prevenção & controle , Anticoagulantes/administração & dosagem , Fibrilação Atrial/complicações , Isquemia Encefálica/terapia , LDL-Colesterol/efeitos dos fármacos , Angiopatias Diabéticas/prevenção & controle , Endarterectomia das Carótidas , Forame Oval Patente/complicações , Cardiopatias/complicações , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Hipertensão/complicações , Coeficiente Internacional Normatizado , Hemorragias Intracranianas/terapia , Stents , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/terapia , Trombectomia , Terapia Trombolítica , Trombose/complicações , Estados Unidos/epidemiologia , Varfarina/administração & dosagem
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