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1.
Cell ; 133(7): 1175-87, 2008 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-18585352

RESUMO

Haploidization of the genome in meiosis requires that chromosomes be sorted exclusively into pairs stabilized by synaptonemal complexes (SCs) and crossovers. This sorting and pairing is accompanied by active chromosome positioning in meiotic prophase in which telomeres cluster near the spindle pole to form the bouquet before dispersing around the nuclear envelope. We now describe telomere-led rapid prophase movements (RPMs) that frequently exceed 1 microm/s and persist throughout meiotic prophase. Bouquet formation and RPMs depend on NDJ1, MPS3, and a new member of this pathway, CSM4, which encodes a meiosis-specific nuclear envelope protein required specifically for telomere mobility. RPMs initiate independently of recombination but differ quantitatively in mutants that fail to complete recombination, suggesting that RPMs respond to recombination status. Together with recombination defects described for ndj1, our observations suggest that RPMs and SCs balance the disruption and stabilization of recombinational interactions, respectively, to regulate crossing over.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Cromossomos Fúngicos/metabolismo , Meiose , Proteínas de Membrana/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/citologia , Telômero/metabolismo , Transporte Biológico , Proteínas de Ciclo Celular/genética , Pareamento Cromossômico , Segregação de Cromossomos , Troca Genética , Proteínas de Membrana/genética , Mutação , Proteínas Nucleares , Recombinação Genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Complexo Sinaptonêmico
2.
Clin Chem ; 61(10): 1283-91, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26283690

RESUMO

BACKGROUND: The association between increases in cardiac troponin and adverse cardiac outcomes is well established. There is a growing interest in exploring routine cardiac troponin monitoring as a potential early indicator of adverse heart health trends. Prognostic use of cardiac troponin measurements requires an assay with very high sensitivity and outstanding analytical performance. We report development and preliminary validation of an investigational assay meeting these requirements and demonstrate its applicability to cohorts of healthy individuals and patients with heart failure. METHODS: On the basis of single molecule array technology, we developed a 45-min immunoassay for cardiac troponin I (cTnI) for use on a novel, fully automated digital analyzer. We characterized its analytical performance and measured cTnI in healthy individuals and heart failure patients in a preliminary study of assay analytical efficacy. RESULTS: The assay exhibited a limit of detection of 0.01 ng/L, a limit of quantification of 0.08 ng/L, and a total CV of 10% at 2.0 ng/L. cTnI concentrations were well above the assay limit of detection for all samples tested, including samples from healthy individuals. cTnI was significantly higher in heart failure patients, and exhibited increasing median and interquartile concentrations with increasing New York Heart Association classification of heart failure severity. CONCLUSIONS: The robust 2-log increase in sensitivity relative to contemporary high-sensitivity cardiac troponin immunoassays, combined with full automation, make this assay suitable for exploring cTnI concentrations in cohorts of healthy individuals and for the potential prognostic application of serial cardiac troponin measurements in both apparently healthy and diseased individuals.


Assuntos
Insuficiência Cardíaca/diagnóstico , Imunoensaio/métodos , Troponina I/sangue , Adulto , Feminino , Insuficiência Cardíaca/sangue , Humanos , Imunoensaio/economia , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Análise Serial de Proteínas/economia , Análise Serial de Proteínas/métodos , Troponina I/análise , Adulto Jovem
4.
PLoS Genet ; 8(5): e1002730, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22654677

RESUMO

Chromosome pairing in meiotic prophase is a prerequisite for the high fidelity of chromosome segregation that haploidizes the genome prior to gamete formation. In the budding yeast Saccharomyces cerevisiae, as in most multicellular eukaryotes, homologous pairing at the cytological level reflects the contemporaneous search for homology at the molecular level, where DNA double-strand broken ends find and interact with templates for repair on homologous chromosomes. Synapsis (synaptonemal complex formation) stabilizes pairing and supports DNA repair. The bouquet stage, where telomeres have formed a transient single cluster early in meiotic prophase, and telomere-promoted rapid meiotic prophase chromosome movements (RPMs) are prominent temporal correlates of pairing and synapsis. The bouquet has long been thought to contribute to the kinetics of pairing, but the individual roles of bouquet and RPMs are difficult to assess because of common dependencies. For example, in budding yeast RPMs and bouquet both require the broadly conserved SUN protein Mps3 as well as Ndj1 and Csm4, which link telomeres to the cytoskeleton through the intact nuclear envelope. We find that mutants in these genes provide a graded series of RPM activity: wild-type>mps3-dCC>mps3-dAR>ndj1Δ>mps3-dNT = csm4Δ. Pairing rates are directly correlated with RPM activity even though only wild-type forms a bouquet, suggesting that RPMs promote homologous pairing directly while the bouquet plays at most a minor role in Saccharomyces cerevisiae. A new collision trap assay demonstrates that RPMs generate homologous and heterologous chromosome collisions in or before the earliest stages of prophase, suggesting that RPMs contribute to pairing by stirring the nuclear contents to aid the recombination-mediated homology search.


Assuntos
Pareamento Cromossômico/genética , Meiose , Saccharomyces cerevisiae , Telômero , Proteínas de Ciclo Celular/genética , Núcleo Celular , Centrômero/genética , Segregação de Cromossomos/genética , Hibridização in Situ Fluorescente , Meiose/genética , Proteínas de Membrana/genética , Mutação , Proteínas Nucleares/genética , Prófase/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Telômero/genética
5.
J Thromb Thrombolysis ; 36(4): 361-7, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23328883

RESUMO

Chest pain is one of the most common reasons for presentation to the Emergency Department and the ability to rapidly and correctly diagnose the minority of patients who have a myocardial infarction is of critical importance. We assessed the diagnostic performance of a multimarker strategy using heart-type fatty acid binding protein (H-FABP) in combination with a contemporary sensitive troponin (cTn) assay. We measured H-FABP (Randox) and a sensitive cTn (TnI-Ultra, Siemens) at baseline in 343 patients with chest pain enrolled in the prospective BWH-TIMI ED chest pain study. Final presenting diagnosis was adjudicated using all diagnostic data, including the local cTnI results, but reviewers were blinded to H-FABP and the sensitive cTn assays. The diagnostic accuracy of H-FABP and local cTn together (AUC 0.962) was superior to local cTn alone (AUC 0.910, p = 0.0009) with an especially marked improvement in early presenters (AUC 0.983 vs. 0.840, p = 0.0098). In contrast, when combined with the sensitive cTn assay, there was no significant difference in the AUC with H-FABP as compared with the sensitive cTn alone, either in the overall cohort (AUC 0.963 vs. 0.956, p = 0.23) or in early presenters (AUC 0.999 for both). In early presenters, the addition of H-FABP resulted in a NPV of 100% when combined with either the local or sensitive cTn assay. In our study, the addition of H-FABP significantly enhanced the sensitivity and accuracy of diagnosis as compared to a prior-generation troponin assay alone, especially in patients who presented early. H-FABP but did improve overall diagnostic accuracy when added to a current-generation sensitive troponin assay; however, their combination offered the best NPV in early presenters. Further studies are needed to determine the utility a very rapid "rule out" of MI with a single blood draw of troponin and H-FABP at presentation.


Assuntos
Dor no Peito/sangue , Dor no Peito/diagnóstico , Proteínas de Ligação a Ácido Graxo/sangue , Infarto do Miocárdio/sangue , Infarto do Miocárdio/diagnóstico , Adulto , Idoso , Proteína 3 Ligante de Ácido Graxo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Troponina I/sangue
6.
Am J Clin Pathol ; 157(6): 809-813, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35038719

RESUMO

OBJECTIVES: In vitro hemolysis generates a spurious increase in potassium. Roche Diagnostics recently revised its recommended guidelines for potassium reporting on cobas analyzers. By dramatically reducing the allowable degree of hemolysis, these guidelines would increase specimen rejection rates. We attempted to balance the desire to avoid inaccurate results with the clinical implications of increased specimen rejection rates. METHODS: We downloaded hemolytic indices (HI) for 80,795 specimens tested at our institution on cobas chemistry analyzers in 1 month and evaluated potential specimen rejection rates based on the new criteria. We also spiked nonhemolyzed samples with hemolyzed blood to assess the influence of HI values on potassium measurements. RESULTS: The new recommendations would lead to specimen rejection rates of 76% in the neonatal intensive care unit (NICU), 41% in the emergency department (ED), 16% in inpatient specimens, and 9% in outpatient samples. Our current criteria of reporting potassium concentrations in inpatient and outpatient specimens with HI ≤100 and in NICU and ED specimens with HI ≤300 and additional interpretive guidance for HI values between 100 and 300 reduce unnecessary specimen rejections to 3% in NICU, 2% in ED and inpatients, and less than 1% in outpatients without significantly increasing the number of clinically consequential incorrect results. CONCLUSIONS: The new recommendations would lead to unacceptably high specimen rejection rates. Laboratories should develop context-specific, evidence-based reporting criteria that minimize reporting of inaccurate results without disrupting delivery of care.


Assuntos
Hemólise , Potássio , Testes Hematológicos , Humanos , Recém-Nascido , Laboratórios
7.
J Pathol Inform ; 13: 100010, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35186704

RESUMO

The ability to access and analyze data is critical to manage a laboratory and respond and adapt to changes, particularly during a pandemic. Data analytic tools can not only improve laboratory operations, but also increase the visibility of the laboratory in the healthcare system and demonstrate the positive impact of the laboratory on patient care. In this article, we describe the creation and utility of laboratory dashboards. Several dashboards were designed to assist with pandemic response. For each dashboard, a stored procedure was created that performed a SQL query of our laboratory information system mirror database. We utilized the business analytics platform, Tableau, for data visualization. Users could modify the data by selecting a specific date range, time window, work shift, institution(s), specific test(s), and/or testing platform(s). Access was controlled by OKTA integration to the host server over the web, behind the hospital firewall. During the April 2020 surge, we saw an increase in blood gas testing and corresponding decrease in non-critical testing such as Vitamin D. At our institution, SARS-CoV-2 molecular testing was performed using four primary platforms, four in-house and one send-out. Weekly and hourly testing volumes as well as turnaround times fluctuated based on reagent availability, new testing requests, staffing, and operational changes. Productivity dashboards indicated that coagulation testing volumes were highest on the third shift and that all three analyzers may not be necessary. Further, specimen volumes and productivity of accessioning staff varied throughout the day. Phlebotomy venipuncture volumes and patient wait times also varied throughout the pandemic. A decrease in ambulatory draws was seen during the surge but after reopening draw volumes, particularly at offsite locations, surpassed prepandemic volumes. We demonstrate that data analytics and interactive dashboards are powerful tools, are helpful in response to a pandemic and lead to improved TAT, supply utilization, staffing and workflows. Furthermore, dashboards provide objective data to review with hospital leadership and promote collaboration.

8.
Lab Med ; 52(4): 329-337, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33438745

RESUMO

OBJECTIVES: To investigate the benefits and challenges of introducing next generation chemistry and coagulation automation. METHODS: We replaced the Roche modular preanalytic system attached to Roche Cobas 6000 analyzers with the Roche 8100 preanalytical line attached to the Roche Cobas 8000 and Stago STA R Max analyzers. The system included 2 add-on buffers (AOBs) for automated specimen archival and retrieval and primary-tube specimen processing. We measured turnaround time (TAT) from specimen receipt to result for chemistry and coagulation tests before, during, and after system implementation. TAT for add-on tests was also measured. RESULTS: We completed the system implementation during a 17-month period using existing laboratory space. The TAT for chemistry, coagulation, and add-on tests decreased significantly (P <.005, P <.001, and P <.005, respectively). We encountered several challenges, including barcode-label errors, mechanical problems, and workflow issues due to lack of bidirectional track for coagulation testing. CONCLUSIONS: Next generation laboratory automation yielded significantly shortened and less-variable TAT, particularly for add-on testing. Our approach could help other laboratories in the process of implementing and configuring automated systems.


Assuntos
Automação Laboratorial , Coagulação Sanguínea , Testes de Coagulação Sanguínea , Humanos , Laboratórios , Fluxo de Trabalho
9.
Curr Biol ; 30(7): 1207-1216.e4, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32059771

RESUMO

Telomere-led rapid chromosome movements or rapid prophase movements direct fundamental meiotic processes required for successful haploidization of the genome. Critical components of the machinery that generates rapid prophase movements are unknown, and the mechanism underlying rapid prophase movements remains poorly understood. We identified S. cerevisiae Mps2 as the outer nuclear membrane protein that connects the LINC complex with the cytoskeleton. We also demonstrate that the motor Myo2 works together with Mps2 to couple the telomeres to the actin cytoskeleton. Further, we show that Csm4 interacts with Mps2 and is required for perinuclear localization of Myo2, implicating Csm4 as a regulator of the Mps2-Myo2 interaction. We propose a model in which the newly identified functions of Mps2 and Myo2 cooperate with Csm4 to drive chromosome movements in meiotic prophase by coupling telomeres to the actin cytoskeleton.


Assuntos
Cromossomos Fúngicos/fisiologia , Proteínas de Membrana/genética , Cadeias Pesadas de Miosina/genética , Miosina Tipo V/genética , Proteínas Nucleares/genética , Prófase/fisiologia , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/fisiologia , Citoesqueleto de Actina/fisiologia , Citoesqueleto/fisiologia , Meiose/fisiologia , Proteínas de Membrana/metabolismo , Cadeias Pesadas de Miosina/metabolismo , Miosina Tipo V/metabolismo , Membrana Nuclear/metabolismo , Proteínas Nucleares/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Telômero/fisiologia
11.
Can J Cardiol ; 35(4): 462-470, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30935637

RESUMO

BACKGROUND: Growth differentiation factor-15 (GDF-15) is a stress-inducible cytokine and member of the transforming growth factor-ß cytokine superfamily that refines prognostic assessment in subgroups of patients with heart failure (HF). We evaluated its role in HF patients with chronic kidney disease (CKD, estimated glomerular filtration rate <60 mL/min/1.73 m2). METHODS: A total of 358 patients with stable systolic HF were followed for a median of 1121 (interquartile range, 379-2600) days. Comprehensive evaluation including B-type natriuretic peptide (BNP) and GDF-15 testing was performed at study entry; the analysis was stratified according to kidney function. RESULTS: Patients with CKD (33.8%) were older, had more often diabetes, and were less often treated with angiotensin converting enzyme inhibitors (ACEi)/angiotensin receptor blockers (ARB). GDF-15 was associated with estimated glomerular filtration rate, whereas BNP was associated with left ventricular-end diastolic diameter and ejection fraction (P < 0.01). During follow-up, 244 patients (68.2%) experienced an adverse outcome (death, urgent transplantation, implantation of mechanical circulatory support). In patients with HF and CKD, the Cox proportional hazard model identified BNP, GDF-15, sex, systolic blood pressure, sodium, total cholesterol, and ACEi/ARB treatment as significant variables associated with an adverse outcome (P < 0.05). In multivariable analysis, BNP was replaced by GDF-15. Net reclassification improvement confirmed prognostic superiority of the model encompassing GDF-15 (GDF-15, sodium, total cholesterol, ACEi/ARB treatment) compared with the model without GDF-15 (BNP, sex, sodium, ACEi/ARB treatment), net reclassification improvement 0.62, P = 0.005. In contrast, in patients with HF and normal kidney function, BNP remained superior to GDF-15 in a multivariable model. CONCLUSIONS: In patients with systolic HF and CKD, GDF-15 is more strongly associated with adverse outcomes than the conventionally used BNP.


Assuntos
Fator 15 de Diferenciação de Crescimento/sangue , Insuficiência Cardíaca Sistólica/sangue , Insuficiência Cardíaca Sistólica/mortalidade , Transplante de Coração/estatística & dados numéricos , Coração Auxiliar/estatística & dados numéricos , Insuficiência Renal Crônica/epidemiologia , Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Biomarcadores/sangue , Pressão Sanguínea , Colesterol/sangue , Feminino , Seguimentos , Taxa de Filtração Glomerular , Insuficiência Cardíaca Sistólica/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeo Natriurético Encefálico/sangue , Modelos de Riscos Proporcionais , Insuficiência Renal Crônica/tratamento farmacológico , Fatores Sexuais , Sódio/sangue , Sístole
12.
Clin Chim Acta ; 395(1-2): 57-61, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18515084

RESUMO

BACKGROUND: While more sensitive cardiac troponin (cTn) assays may overcome current limitations in diagnosing acute coronary syndrome (ACS), clinicians and laboratorians are concerned about the clinical impact of higher rates of cTn positivity. METHODS: We collected statistics on test volume and positivity rates before and after the implementation of a more sensitive assay. We divided patients into 6 groups based on their cardiac troponin I (cTnI) results and utilized additional laboratory test results to determine the impact of the new assay. In addition, we assessed the clinical significance of low-positive cTnI results (0.05-0.10 microg/l). RESULTS: Lowering the diagnostic cutoff from 0.10 to 0.04 microg/l increased the number of positive test results by 44.2% hospital-wide and 114.4% in the emergency department without significantly changing test volume. In some patients, low-positive results were part of the typical rise and fall of cTnI consistent with myocardial damage. Diagnosis was more challenging in patients with consistently low-positive results. Patients in this group were significantly more likely to have impaired renal function than those with cTnI elevations >0.10 microg/l. CONCLUSIONS: More sensitive cTn assays will increase the number of positive results and allow for earlier detection of cardiac injury while also detecting non-ACS related pathologies.


Assuntos
Síndrome Coronariana Aguda/sangue , Insuficiência Renal Crônica/sangue , Troponina I/sangue , Síndrome Coronariana Aguda/diagnóstico , Taxa de Filtração Glomerular , Humanos , Testes de Função Renal/métodos , Valor Preditivo dos Testes , Insuficiência Renal Crônica/diagnóstico , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Volume Sistólico
13.
Transplantation ; 101(1): 182-190, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26910333

RESUMO

BACKGROUND: Approximately 200 000 kidney transplant recipients are living in the United States; they are at increased risk for cardiovascular and other adverse outcomes. Biomarkers predicting these outcomes are needed. Using specimens collected during the Folic Acid for Vascular Outcome Reduction in Transplantation trial, we determined whether plasma levels of B-type natriuretic peptide (BNP) and cardiac troponin I are associated with adverse outcomes in stable kidney transplant recipients. METHODS: Five hundred ten subjects were selected randomly from the 4110 Folic Acid for Vascular Outcome Reduction in Transplantation participants. This cohort was then enriched for all additional subjects with adverse outcomes (death, dialysis-dependent kidney failure (DDKF), and cardiovascular outcomes) for a total of 1131 participants studied. Quartiles of BNP and high-sensitivity cardiac troponin I (hs-cTnI) were included in adjusted models. Combinations of normal and elevated hs-cTnI (>26.2 ng/L) and BNP (>100 pg/mL) were also studied. RESULTS: Median concentrations (interquartile ranges) were 5.6 (3.3-10.5) ng/L for hs-cTnI and 39 (15, 94) pg/mL for BNP. Hazard ratios for each adverse outcome were higher with higher quartiles of BNP after adjustment and remained statistically significant after adding hs-cTnI to the model. The highest quartile hazard ratio for DDKF was 2.47 (95% confidence interval [95% CI], 1.21-5.05). Simultaneous elevations of BNP and hs-cTnI over clinical cutoffs were strongly associated with adverse outcomes with hazard ratios 8.8 (95% CI, 3.4-23.1) for DDKF and 6.3 (95% CI, 2.7-15.0) for cardiovascular outcomes. CONCLUSIONS: Higher BNP is associated with mortality and cardiovascular and kidney outcomes in stable kidney transplant recipients. Elevated BNP and hs-cTnI identify candidates for targeted risk reduction.


Assuntos
Doenças Cardiovasculares/sangue , Transplante de Rim/efeitos adversos , Peptídeo Natriurético Encefálico/sangue , Transplantados , Troponina I/sangue , Adulto , Biomarcadores/sangue , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/mortalidade , Estudos de Casos e Controles , Feminino , Humanos , Transplante de Rim/mortalidade , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco , Resultado do Tratamento , Regulação para Cima
14.
J Interv Card Electrophysiol ; 47(1): 69-74, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26971332

RESUMO

BACKGROUND: Radiofrequency ablation results in intentional cardiac injury. We aimed to assess the kinetics of cardiac injury as measured by cardiac troponin release following ventricular ablation and atrial ablation. METHODS: Patients undergoing ablation for ventricular tachycardia (VT) with structural heart disease (19 patients) or atrial fibrillation (AF, 24 patients) were prospectively enrolled. High-sensitivity cardiac troponin T (hs-cTnT) and high-sensitivity cardiac troponin I (hs-cTnI) were measured before ablation as well as 30 min, 60 min, 90 min, 120 min, 4 h, 8 h, and 24 h after applying the first ablation lesion. RESULTS: Median ablation time, power used, and energy delivered were 28 min, 39 W, and 69,713 J in VT ablations and 55 min, 29 W, and 95,425 J in AF ablations, respectively. Release of hs-cTnT occurred promptly with both, but reached greater levels earlier for ventricular compared to atrial ablation (hs-cTnT after 30 min 191 vs. 31 ng/l, after 1 h 467 vs. 80 ng/l; hs-cTnI after 30 min 132 vs. 30 ng/l, after 1 h 331 vs. 76 ng/l; p < 0.001 for all comparisons). After 24 h, levels were similar (hs-cTnT 1325 vs. 1303 ng/l, p = 0.92; hs-cTnI 2165 vs. 1996 ng/l, p = 0.55). Levels of hs-cTnT after 24 h correlated well with the energy delivered in AF ablations (r = 0.81 and r = 0.75, p < 0.001), but not in VT ablations (r = 0.35 and r = 0.44, p = ns). CONCLUSIONS: Evidence of cardiac injury as indicated by the release of hs-cTnT and hs-cTnI occurs early with atrial and ventricular ablation. Higher early levels are observed in ventricular ablations, but levels are similar after 24 h. The extent of total troponin release seems to correlate well with the amount of energy delivered in AF ablations, but not in VT ablations.


Assuntos
Fibrilação Atrial/cirurgia , Ablação por Cateter/efeitos adversos , Traumatismos Cardíacos/sangue , Traumatismos Cardíacos/etiologia , Taquicardia Ventricular/cirurgia , Troponina I/sangue , Idoso , Fibrilação Atrial/sangue , Fibrilação Atrial/diagnóstico , Biomarcadores/sangue , Ablação por Cateter/métodos , Traumatismos Cardíacos/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Taquicardia Ventricular/sangue , Taquicardia Ventricular/diagnóstico , Resultado do Tratamento
15.
Mutat Res ; 570(2): 163-73, 2005 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-15708575

RESUMO

Pds5p is a cohesin related protein. It is required for maintenance of sister chromatid cohesion in mitosis and meiosis. Here we report that pds5-1 causes cell death in yeast Saccharomyces cerevisiae during early meiosis. The pds5-1 caused cell death possesses characteristics of apoptosis and necrosis, including externalization of phosphatidylserine at cytoplasmic membrane, accumulation of DNA breaks, chromatin condensation and fragmentation, nuclei fragmentation, membrane degeneration and cell size enlargement. Our results also suggest that (1) The defect of DNA repair; (2) The production of reactive oxygen species, in pds5-1 mutant are involved in pds5-1 induced cell death.


Assuntos
Proteínas de Ciclo Celular/genética , Meiose/genética , Mutação , Saccharomyces cerevisiae/genética , Reparo do DNA , Genes Fúngicos , Microscopia Eletrônica , Espécies Reativas de Oxigênio , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/efeitos da radiação , Proteínas de Saccharomyces cerevisiae , Raios Ultravioleta
16.
Dis Markers ; 2015: 157812, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25960590

RESUMO

OBJECTIVE: To determine the proportion of initial troponin (cTn) elevations associated with Type I MI versus other cardiovascular and noncardiovascular diagnoses in an emergency department (ED) and whether or not a relationship exists between the cTn level and the likelihood of Type I MI. BACKGROUND: In the ED, cTn is used as a screening test for myocardial injury. However, the differential diagnosis for an initial positive cTn result is not clear. METHODS: Hospital medical records were retrospectively reviewed for visits associated with an initial positive troponin I-ultra (cTnI), ≥0.05 µg/L. Elevated cTnI levels were stratified into low (0.05-0.09), medium (0.1-0.99), or high (≥1.0). Discharge diagnoses were classified into 3 diagnostic groups (Type I MI, other cardiovascular, or noncardiovascular). RESULTS: Of 23,731 ED visits, 4,928 (21%) had cTnI testing. Of those tested, 16.3% had initial cTnI ≥0.05. Among those with elevated cTn, 11% were classified as Type I MI, 34% had other cardiovascular diagnoses, and 55% had a noncardiovascular diagnosis. Type I MI was more common with high cTnI levels (41% incidence) than among subjects with medium (9%) or low (6%). CONCLUSION: A positive cTn is most likely a noncardiovascular diagnosis, but Type I MI is far more common with cTnI levels ≥1.0.


Assuntos
Serviço Hospitalar de Emergência/estatística & dados numéricos , Infarto do Miocárdio/sangue , Troponina I/sangue , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
17.
Eur Heart J Acute Cardiovasc Care ; 4(5): 431-40, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25538086

RESUMO

BACKGROUND: Newer troponin assays offer the ability to quantify circulating troponin levels at an order of magnitude lower than contemporary assays, fueling continued debate over the prognostic implications of very low-level increases in concentration. We evaluated the prognostic implications of low-level increases in cardiac troponin I (cTnI) using an investigational single-molecule high-sensitivity assay in patients with acute coronary syndrome (ACS). METHODS: We measured cTnI using both a high-sensitivity troponin I (hsTnI) assay (Erenna, Singulex, 99(th) percentile 9 pg/ml) and a current generation sensitive assay (TnI-Ultra, Siemens, 99(th) percentile 40 pg/ml) at baseline in 1807 patients with non-ST elevation ACS and compared their prognostic ability for adverse cardiovascular events at 30 days and one year. RESULTS: Among patients with TnI-Ultra<99(th) percentile, patients with elevated hsTnI (≥ 9 pg/ml) had a significantly higher risk than patients with hsTnI<9 pg/ml: cardiovascular death (CVD) or myocardial infarction (MI) at one year (7.0% vs 3.8%; p<0.001, hazard ratio (HR) 2.05, confidence interval (CI) 1.23-3.41); including a higher risk of CVD (3.5% vs 1.5%, p<0.001) and MI (5.0% vs 2.8%, p<0.001) individually. This higher risk of CVD/MI was independent of clinical risk stratification using the TIMI Risk Score (adj. HR 1.76, CI 1.05-2.90). Moreover, hsTnI showed a trend toward a gradient of risk even below the hsTnI 99 percentile. CONCLUSIONS: Low-level cardiac troponin detected using a single-molecule technique, below the cutpoint of a contemporary sensitive assay, identified a significant gradient of risk. These findings support the prognostic relevance of low-level cardiac troponin elevation with increasingly sensitive assays in patients with ACS.


Assuntos
Síndrome Coronariana Aguda/sangue , Biomarcadores/sangue , Troponina I/sangue , Síndrome Coronariana Aguda/diagnóstico , Síndrome Coronariana Aguda/tratamento farmacológico , Idoso , Fármacos Cardiovasculares/administração & dosagem , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/mortalidade , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Ranolazina/administração & dosagem , Fatores de Risco , Sensibilidade e Especificidade
18.
Clin Cardiol ; 38(4): 230-5, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25737394

RESUMO

BACKGROUND: High-sensitivity cardiac troponin T (hsTnT) is used in many countries, but is not available in the United States. Prior evidence has been viewed as inconclusive as to whether low cardiac troponin T (cTnT) concentrations detected with hsTnT are prognostically meaningful compared with fourth-generation cTnT. HYPOTHESIS: The aim of this study was to assess the prognostic performance of low-level cTnT elevations using the hsTnT assay compared with the assay (fourth-generation) currently available in the United States. METHODS: We measured serum cTnT in 4160 patients with non-ST-elevation acute coronary syndrome using both the hsTnT and fourth-generation assays. Patients were stratified at the 99th percentile cut point for each assay. RESULTS: Patients with baseline hsTnT ≥14 ng/L (n = 3697) vs <14 ng/L were at higher 30-day risk of cardiovascular death (CVD) or myocardial infarction (MI) (9.1% vs 1.9%, P < 0.0001). After adjusting for all other elements of the Thrombolysis In Myocardial Infarction risk score, hsTnT ≥14 carried a 5.2-fold higher risk of CVD/MI (95% confidence interval [CI]: 2.6-10.1, P < 0.0001). Low levels of hsTnT (14-50 ng/L) also revealed increased risk (CVD/MI: 6.4%, P = 0.002). Importantly, patients with negative fourth-generation cTnT but positive hsTnT were at 4.5-times higher risk of CVD/MI (95% CI: 1.9-11.0, P = 0.0008) than patients with negative hsTnT. In contrast, patients with a negative hsTnT but positive fourth-generation cTnT result had a lower rate of CVD/MI than with a positive hsTnT (1.3% vs 8.2%, P = 0.0005). CONCLUSIONS: Low-level increases in cTnT detected using the hsTnT assay identified patients at a meaningfully higher risk and who might otherwise be missed, and improves upon risk stratification using the cTnT assay currently available in the United States.


Assuntos
Síndrome Coronariana Aguda/sangue , Síndrome Coronariana Aguda/diagnóstico , Troponina T/sangue , Bioensaio/normas , Biomarcadores/sangue , Testes de Química Clínica/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico
19.
Clin Lab Med ; 34(1): 59-73, vi, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24507787

RESUMO

Measurement of circulating cardiac troponins I and T has become integral to the diagnosis of myocardial infarction. This article discusses the structure and function of the troponin complex and the release of cardiac troponin molecules from the injured cardiomyocyte into the circulation. An overview of current cardiac troponin assays and their classification according to sensitivity is presented. The diagnostic criteria, role, and usefulness of cardiac troponin for myocardial infarction are discussed. In addition, several examples are given of the usefulness of high-sensitivity cardiac troponin assays for short-term and long-term prediction of adverse events.


Assuntos
Síndrome Coronariana Aguda/diagnóstico , Infarto do Miocárdio/diagnóstico , Troponina/sangue , Humanos , Prognóstico , Processamento de Proteína Pós-Traducional , Troponina/genética
20.
J Cell Biol ; 205(5): 643-61, 2014 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-24914236

RESUMO

The chromosome-like mitotic stability of the yeast 2 micron plasmid is conferred by the plasmid proteins Rep1-Rep2 and the cis-acting locus STB, likely by promoting plasmid-chromosome association and segregation by hitchhiking. Our analysis reveals that stable plasmid segregation during meiosis requires the bouquet proteins Ndj1 and Csm4. Plasmid relocalization from the nuclear interior in mitotic cells to the periphery at or proximal to telomeres rises from early meiosis to pachytene. Analogous to chromosomes, the plasmid undergoes Csm4- and Ndj1-dependent rapid prophase movements with speeds comparable to those of telomeres. Lack of Ndj1 partially disrupts plasmid-telomere association without affecting plasmid colocalization with the telomere-binding protein Rap1. The plasmid appears to engage a meiosis-specific motor that orchestrates telomere-led chromosome movements for its telomere-associated segregation during meiosis I. This hitherto uncharacterized mode of germ-line transmission by a selfish genetic element signifies a mechanistic variation within the shared theme of chromosome-coupled plasmid segregation during mitosis and meiosis.


Assuntos
DNA Fúngico/genética , Regulação Fúngica da Expressão Gênica , Meiose , Sequências Repetitivas de Ácido Nucleico/genética , Saccharomyces cerevisiae/genética , Telômero/ultraestrutura , Proteínas de Ciclo Celular/genética , Segregação de Cromossomos , Cromossomos Fúngicos/genética , Proteínas do Citoesqueleto/genética , Genes Reporter , Proteínas de Fluorescência Verde/metabolismo , Cinetocoros , Proteínas de Membrana/genética , Mitose , Proteínas Nucleares/genética , Plasmídeos/metabolismo , Prófase , Proteínas de Saccharomyces cerevisiae/genética , Complexo Shelterina , Fuso Acromático/genética , Proteínas de Ligação a Telômeros/genética , Fatores de Transcrição/genética
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