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1.
Europace ; 25(12)2023 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-38006390

RESUMO

AIMS: The mechanisms of transition from regular rhythms to ventricular fibrillation (VF) are poorly understood. The concordant to discordant repolarization alternans pathway is extensively studied; however, despite its theoretical centrality, cannot guide ablation. We hypothesize that complex repolarization dynamics, i.e. oscillations in the repolarization phase of action potentials with periods over two of classic alternans, is a marker of electrically unstable substrate, and ablation of these areas has a stabilizing effect and may reduce the risk of VF. To prove the existence of higher-order periodicities in human hearts. METHODS AND RESULTS: We performed optical mapping of explanted human hearts obtained from recipients of heart transplantation at the time of surgery. Signals recorded from the right ventricle endocardial surface were processed to detect global and local repolarization dynamics during rapid pacing. A statistically significant global 1:4 peak was seen in three of six hearts. Local (pixel-wise) analysis revealed the spatially heterogeneous distribution of Periods 4, 6, and 8, with the regional presence of periods greater than two in all the hearts. There was no significant correlation between the underlying restitution properties and the period of each pixel. CONCLUSION: We present evidence of complex higher-order periodicities and the co-existence of such regions with stable non-chaotic areas in ex vivo human hearts. We infer that the oscillation of the calcium cycling machinery is the primary mechanism of higher-order dynamics. These higher-order regions may act as niduses of instability and may provide targets for substrate-based ablation of VF.


Assuntos
Ventrículos do Coração , Coração , Humanos , Arritmias Cardíacas , Fibrilação Ventricular/cirurgia , Potenciais de Ação/fisiologia
2.
medRxiv ; 2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37662394

RESUMO

Background: Repolarization alternans, defined as period-2 oscillation in the repolarization phase of the action potentials, provides a mechanistic link between cellular dynamics and ventricular fibrillation (VF). Theoretically, higher-order periodicities (e.g., periods 4, 6, 8,...) are expected but have minimal experimental evidence. Methods: We studied explanted human hearts obtained from recipients of heart transplantation at the time of surgery. Optical mapping of the transmembrane potential was performed after staining the hearts with voltage-sensitive fluorescent dyes. Hearts were stimulated at an increasing rate until VF was induced. Signals recorded from the right ventricle endocardial surface prior to induction of VF and in the presence of 1:1 conduction were processed using the Principal Component Analysis and a combinatorial algorithm to detect and quantify higher-order dynamics. Results were correlated to the underlying electrophysiological characteristics as quantified by restitution curves and conduction velocity. Results: A prominent and statistically significant global 1:4 peak (corresponding to period-4 dynamics) was seen in three of the six studied hearts. Local (pixel-wise) analysis revealed the spatially heterogeneous distribution of periods 4, 6, and 8, with the regional presence of periods greater than two in all the hearts. There was no significant correlation between the underlying restitution properties and the period of each pixel. Discussion: We present evidence of higher-order periodicities and the co-existence of such regions with stable non-chaotic areas in ex-vivo human hearts. We infer from the independence of the period to the underlying restitution properties that the oscillation of the excitation-contraction coupling and calcium cycling mechanisms is the primary mechanism of higher-order dynamics. These higher-order regions may act as niduses of instability that can degenerate into chaotic fibrillation and may provide targets for substrate-based ablation of VF.

3.
bioRxiv ; 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37205562

RESUMO

Background: Repolarization alternans, defined as period-2 oscillation in the repolarization phase of the action potentials, is one of the cornerstones of cardiac electrophysiology as it provides a mechanistic link between cellular dynamics and ventricular fibrillation (VF). Theoretically, higher-order periodicities (e.g., period-4, period-8,...) are expected but have very limited experimental evidence. Methods: We studied explanted human hearts, obtained from the recipients of heart transplantation at the time of surgery, using optical mapping technique with transmembrane voltage-sensitive fluorescent dyes. The hearts were stimulated at an increasing rate until VF was induced. The signals recorded from the right ventricle endocardial surface just before the induction of VF and in the presence of 1:1 conduction were processed using the Principal Component Analysis and a combinatorial algorithm to detect and quantify higher-order dynamics. Results: A prominent and statistically significant 1:4 peak (corresponding to period-4 dynamics) was seen in three of the six studied hearts. Local analysis revealed the spatiotemporal distribution of higher-order periods. Period-4 was localized to temporally stable islands. Higher-order oscillations (period-5, 6, and 8) were transient and primarily occurred in arcs parallel to the activation isochrones. Discussion: We present evidence of higher-order periodicities and the co-existence of such regions with stable non-chaotic areas in ex-vivo human hearts before VF induction. This result is consistent with the period-doubling route to chaos as a possible mechanism of VF initiation, which complements the concordant to discordant alternans mechanism. The presence of higher-order regions may act as niduses of instability that can degenerate into chaotic fibrillation.

6.
ESC Heart Fail ; 8(3): 2349-2353, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33787080

RESUMO

AIMS: Outflow graft obstruction is a poorly described complication following left ventricular assist device (LVAD) surgery. We sought to define the incidence of LVAD outflow graft obstruction and assess clinical outcomes with a percutaneous treatment strategy. METHODS AND RESULTS: From January 2012 to October 2020, 322 patients with LVAD were managed at our institution. Patients with LVAD outflow graft obstruction were identified by cardiac computed tomography with angiography and invasive haemodynamic assessment and were subsequently treated with percutaneous intervention. Poisson regression was used to analyse time-dependent differences in the incidence of LVAD outflow graft obstruction. Kaplan-Meier analysis was used to estimate survival. Twenty patients (6.2%) developed haemodynamically significant LVAD outflow graft obstruction at a rate of 0.03 events per patient-year. Outflow graft obstruction presented a median of 33 (26-49) months after surgery. Patients presented with low estimated LVAD pump flow (95%), heart failure (90%), or both (85%), and 59% developed cardiogenic shock prior to intervention. The most common aetiology identified by cardiac computed tomography with angiography was external compression of the outflow graft (78%). On presentation, the median peak gradient in the outflow graft was 78 (64-100) mmHg. Outflow graft stenting was 100% successful with no in-hospital mortality, and it reduced the peak outflow graft gradient to 10 (2-17) mmHg (P < 0.001). Outflow graft stenting was durable with two patients (10%) requiring a repeat procedure over a median follow-up of 13 (7-20) months and did not impact survival. CONCLUSIONS: Left ventricular assist device outflow graft obstruction is a relatively common and underappreciated cause of recurrent heart failure and LVAD dysfunction. Outflow graft stenting can be achieved with low morbidity and provides a long-term solution to this complication.


Assuntos
Insuficiência Cardíaca , Coração Auxiliar , Coração Auxiliar/efeitos adversos , Mortalidade Hospitalar , Humanos , Estudos Retrospectivos , Choque Cardiogênico/epidemiologia , Choque Cardiogênico/etiologia
7.
Circ Cardiovasc Genet ; 10(4)2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28798024

RESUMO

BACKGROUND: The screening of Icelandic patients clinically diagnosed with hypertrophic cardiomyopathy resulted in identification of 8 individuals from 2 families with X-linked Fabry disease (FD) caused by GLA(α-galactosidase A gene) mutations encoding p.D322E (family A) or p.I232T (family B). METHODS AND RESULTS: Familial screening of at-risk relatives identified mutations in 16 family A members (8 men and 8 heterozygotes) and 25 family B members (10 men and 15 heterozygotes). Clinical assessments, α-galactosidase A (α-GalA) activities, glycosphingolipid substrate levels, and in vitro mutation expression were used to categorize p.D322E as a classic FD mutation and p.I232T as a later-onset FD mutation. In vitro expression revealed that p.D322E and p.I232T had α-GalA activities of 1.4% and 14.9% of the mean wild-type activity, respectively. Family A men had markedly decreased α-GalA activity and childhood-onset classic manifestations, except for angiokeratoma and cornea verticillata. Family B men had residual α-GalA activity and developed FD manifestations in adulthood. Despite these differences, all family A and family B men >30 years of age had left ventricular hypertrophy, which was mainly asymmetrical, and had similar late gadolinium enhancement patterns. Ischemic stroke and severe white matter lesions were more frequent among family A men, but neither family A nor family B men had overt renal disease. Family A and family B heterozygotes had less severe or no clinical manifestations. CONCLUSIONS: Men with classic or later-onset FD caused by GLA missense mutations developed prominent and similar cardiovascular disease at similar ages, despite markedly different α-GalA activities.


Assuntos
Cardiomiopatia Hipertrófica/diagnóstico , Doença de Fabry/diagnóstico , Adolescente , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Cardiomiopatia Hipertrófica/complicações , Cardiomiopatia Hipertrófica/genética , Criança , Doença de Fabry/complicações , Doença de Fabry/genética , Feminino , Genótipo , Heterozigoto , Humanos , Nefropatias/complicações , Nefropatias/diagnóstico , Transtornos de Início Tardio , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Linhagem , Fenótipo , Adulto Jovem , alfa-Galactosidase/genética
8.
Brachytherapy ; 15(6): 760-767, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27720202

RESUMO

PURPOSE: Cost estimates through traditional hospital accounting systems are often arbitrary and ambiguous. We used time-driven activity-based costing (TDABC) to determine the true cost of low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy for prostate cancer and demonstrate opportunities for cost containment at an academic referral center. METHODS AND MATERIALS: We implemented TDABC for patients treated with I-125, preplanned LDR and computed tomography based HDR brachytherapy with two implants from initial consultation through 12-month followup. We constructed detailed process maps for provision of both HDR and LDR. Personnel, space, equipment, and material costs of each step were identified and used to derive capacity cost rates, defined as price per minute. Each capacity cost rate was then multiplied by the relevant process time and products were summed to determine total cost of care. RESULTS: The calculated cost to deliver HDR was greater than LDR by $2,668.86 ($9,538 vs. $6,869). The first and second HDR treatment day cost $3,999.67 and $3,955.67, whereas LDR was delivered on one treatment day and cost $3,887.55. The greatest overall cost driver for both LDR and HDR was personnel at 65.6% ($4,506.82) and 67.0% ($6,387.27) of the total cost. After personnel costs, disposable materials contributed the second most for LDR ($1,920.66, 28.0%) and for HDR ($2,295.94, 24.0%). CONCLUSIONS: With TDABC, the true costs to deliver LDR and HDR from the health system perspective were derived. Analysis by physicians and hospital administrators regarding the cost of care afforded redesign opportunities including delivering HDR as one implant. Our work underscores the need to assess clinical outcomes to understand the true difference in value between these modalities.


Assuntos
Braquiterapia/economia , Custos de Cuidados de Saúde/estatística & dados numéricos , Neoplasias da Próstata/economia , Neoplasias da Próstata/radioterapia , Centros Médicos Acadêmicos/economia , Braquiterapia/métodos , California , Controle de Custos/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/cirurgia , Dosagem Radioterapêutica
9.
Sci Rep ; 6: 22235, 2016 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-26917049

RESUMO

Cardiomyopathy is an important cause of heart failure in Sub-Saharan Africa, accounting for up to 30% of adult heart failure hospitalisations. This high prevalence poses a challenge in societies without access to resources and interventions essential for disease management. Over 80 genes have been implicated as a cause of cardiomyopathy. Mutations in the phospholamban (PLN) gene are associated with dilated cardiomyopathy (DCM) and severe heart failure. In Africa, the prevalence of PLN mutations in cardiomyopathy patients is unknown. Our aim was to screen 315 patients with arrhythmogenic right ventricular cardiomyopathy (n = 111), DCM (n = 95), hypertrophic cardiomyopathy (n = 40) and peripartum cardiomyopathy (n = 69) for disease-causing PLN mutations by high resolution melt analysis and DNA sequencing. We detected the previously reported PLN c.25C > T (p.R9C) mutation in a South African family with severe autosomal dominant DCM. Haplotype analysis revealed that this mutation occurred against a different haplotype background to that of the original North American family and was therefore unlikely to have been inherited from a common ancestor. No other mutations in PLN were detected (mutation prevalence = 0.2%). We conclude that PLN is a rare cause of cardiomyopathy in African patients. The PLN p.R9C mutation is not well-tolerated, emphasising the importance of this gene in cardiac function.


Assuntos
Displasia Arritmogênica Ventricular Direita/genética , Proteínas de Ligação ao Cálcio/genética , Cardiomiopatia Dilatada/genética , Cardiomiopatia Hipertrófica/genética , Mutação , Complicações Cardiovasculares na Gravidez/genética , Displasia Arritmogênica Ventricular Direita/diagnóstico , Sequência de Bases , Cardiomiopatia Dilatada/diagnóstico , Cardiomiopatia Hipertrófica/diagnóstico , Análise Mutacional de DNA/métodos , Saúde da Família , Feminino , Predisposição Genética para Doença/genética , Testes Genéticos/métodos , Haplótipos , Humanos , Masculino , Linhagem , Período Periparto , Gravidez , Complicações Cardiovasculares na Gravidez/diagnóstico , Homologia de Sequência de Aminoácidos , África do Sul
10.
Cancer ; 122(3): 447-55, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26524087

RESUMO

BACKGROUND: Given the costs of delivering care for men with prostate cancer remain poorly described, this article reports the results of time-driven activity-based costing (TDABC) for competing treatments of low-risk prostate cancer. METHODS: Process maps were developed for each phase of care from the initial urologic visit through 12 years of follow-up for robotic-assisted laparoscopic prostatectomy (RALP), cryotherapy, high-dose rate (HDR) and low-dose rate (LDR) brachytherapy, intensity-modulated radiation therapy (IMRT), stereotactic body radiation therapy (SBRT), and active surveillance (AS). The last modality incorporated both traditional transrectal ultrasound (TRUS) biopsy and multiparametric-MRI/TRUS fusion biopsy. The costs of materials, equipment, personnel, and space were calculated per unit of time and based on the relative proportion of capacity used. TDABC for each treatment was defined as the sum of its resources. RESULTS: Substantial cost variation was observed at 5 years, with costs ranging from $7,298 for AS to $23,565 for IMRT, and they remained consistent through 12 years of follow-up. LDR brachytherapy ($8,978) was notably cheaper than HDR brachytherapy ($11,448), and SBRT ($11,665) was notably cheaper than IMRT, with the cost savings attributable to shorter procedure times and fewer visits required for treatment. Both equipment costs and an inpatient stay ($2,306) contributed to the high cost of RALP ($16,946). Cryotherapy ($11,215) was more costly than LDR brachytherapy, largely because of increased single-use equipment costs ($6,292 vs $1,921). AS reached cost equivalence with LDR brachytherapy after 7 years of follow-up. CONCLUSIONS: The use of TDABC is feasible for analyzing cancer services and provides insights into cost-reduction tactics in an era focused on emphasizing value. By detailing all steps from diagnosis and treatment through 12 years of follow-up for low-risk prostate cancer, this study has demonstrated significant cost variation between competing treatments.


Assuntos
Braquiterapia/economia , Custos de Cuidados de Saúde , Vigilância da População , Prostatectomia/economia , Neoplasias da Próstata/economia , Neoplasias da Próstata/terapia , Radiocirurgia/economia , Radioterapia de Intensidade Modulada/economia , Idoso , Idoso de 80 Anos ou mais , Análise Custo-Benefício , Estudos de Viabilidade , Humanos , Laparoscopia/economia , Masculino , Pessoa de Meia-Idade , Prostatectomia/métodos , Neoplasias da Próstata/patologia , Medição de Risco , Fatores de Risco , Procedimentos Cirúrgicos Robóticos/economia , Estados Unidos , Conduta Expectante/economia
11.
Urol Pract ; 3(3): 180-186, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-37592506

RESUMO

INTRODUCTION: We report the implementation of time driven, activity based costing for competing treatments of small renal masses at an academic referral center. METHODS: To use time driven, activity based costing we developed a process map outlining the steps to treat small renal masses. We then derived the costs of supplying every resource per unit time. Known as the capacity cost rate, this included equipment and its depreciation (eg price per minute of the operating room table), personnel and space (eg cost per minute to rent clinic space). We multiplied each capacity cost rate by the time for each step. Time driven, activity based costing was defined as the sum of the products for each intervention. RESULTS: Robot-assisted laparoscopic partial nephrectomy was the most expensive treatment for small renal masses. It was 69.7% more costly than the most inexpensive inpatient modality, laparoscopic radical nephrectomy ($17,841.79 vs $10,514.05). Equipment costs were greater for laparoscopic radical nephrectomy than for open partial nephrectomy. However for laparoscopic radical nephrectomy vs open partial nephrectomy the lower personnel capacity cost rate due to faster operating room time (195.2 vs 217.3 minutes, p = 0.001) and shorter length of stay (2.4 vs 3.7 days, p = 0.13) were the primary drivers in lowering costs. Radiofrequency ablation was 48.4% less expensive than laparoscopic radical nephrectomy ($5,093.83 vs $10,514.05) largely by avoiding inpatient costs. Renal biopsy contributed 3.5% vs 12.2% to the overall cost of robot-assisted laparoscopic partial nephrectomy vs radiofrequency ablation but it may allow for increased active surveillance. CONCLUSIONS: Using time driven, activity based costing we determined the relative resource utilization of competing small renal mass treatments, finding significant cost differences among various treatments. This informs value considerations, which are particularly relevant in the current health care milieu.

12.
Neurosurgery ; 75(2): 99-109; discussion 109, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24681644

RESUMO

Reliable delivery of optimal care can be challenging for care providers. Health care leaders have integrated various business tools to assist them and their teams in ensuring consistent delivery of safe and top-quality care. The cornerstone to all quality improvement strategies is the detailed understanding of the current state of a process, captured by process mapping. Process mapping empowers caregivers to audit how they are currently delivering care to subsequently strategically plan improvement initiatives. As a community, neurosurgery has clearly shown dedication to enhancing patient safety and delivering quality care. A care redesign strategy named NERVS (Neurosurgery Enhanced Recovery after surgery, Value, and Safety) is currently being developed and piloted within our department. Through this initiative, a multidisciplinary team led by a clinician neurosurgeon has process mapped the way care is currently being delivered throughout the entire episode of care. Neurosurgeons are becoming leaders in quality programs, and their education on the quality improvement strategies and tools is essential. The authors present a comprehensive review of process mapping, demystifying its planning, its building, and its analysis. The particularities of using process maps, initially a business tool, in the health care arena are discussed, and their specific use in an academic neurosurgical department is presented.


Assuntos
Neurocirurgia/normas , Assistência ao Paciente/normas , Avaliação de Processos em Cuidados de Saúde/normas , Garantia da Qualidade dos Cuidados de Saúde , Melhoria de Qualidade , Humanos , Segurança do Paciente/normas , Indicadores de Qualidade em Assistência à Saúde
13.
FASEB J ; 26(11): 4685-95, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22874833

RESUMO

Sucrose nonfermenting 1 (Snf1)-related kinase (SNRK) is a serine/threonine kinase with sequence similarity to AMP-activated protein kinase (AMPK); however, its function is not well characterized. We conducted a gene array to determine which genes are regulated by SNRK. The array demonstrated that SNRK overexpression increased the levels of genes involved in cell proliferation, including calcyclin-binding protein (CacyBP), a member of the ubiquitin ligase complex that targets nonphosphorylated ß-catenin for degradation. We confirmed that SNRK increased CacyBP mRNA and protein, and decreased ß-catenin protein in HCT116 and RKO colon cancer cells. Furthermore, SNRK inhibited colon cancer cell proliferation, and CacyBP down-regulation reversed the SNRK-mediated decrease in proliferation and ß-catenin. SNRK overexpression also decreased ß-catenin nuclear localization and target gene transcription, and ß-catenin down-regulation reversed the effects of SNRK knockdown on proliferation. SNRK transcript levels were reduced in human colon tumors compared to normal tissue by 35.82%, and stable knockdown of SNRK increased colon cancer cell tumorigenicity. Our results demonstrate that SNRK is down-regulated in colon cancer and inhibits colon cancer cell proliferation through CacyBP up-regulation and ß-catenin degradation, resulting in reduced proliferation signaling. These findings reveal a novel function for SNRK in the regulation of colon cancer cell proliferation and ß-catenin signaling.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Neoplasias do Colo/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , beta Catenina/metabolismo , Proteínas de Ligação ao Cálcio/genética , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias do Colo/patologia , Regulação Neoplásica da Expressão Gênica/fisiologia , Técnicas de Silenciamento de Genes , Humanos , Proteínas Serina-Treonina Quinases/genética , Transdução de Sinais/fisiologia , Transcriptoma , beta Catenina/genética
14.
Am Heart J ; 161(5): 832-41, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21570511

RESUMO

Clopidogrel use is associated with a significant decrease in major adverse cardiac events when used in patients with non-ST elevation acute coronary syndromes (NSTE-ACS), and guidelines give a class I level of evidence A recommendation for the use of clopidogrel in these patients. The optimal timing of clopidogrel use has not been conclusively determined, but nearly all data available support early use in patients with NSTE-ACS. Despite this, clopidogrel usage is far less than expected based on current guidelines because of concern for bleeding at the time of possible subsequent coronary artery bypass grafting (CABG). Clopidogrel use has been associated with increased perioperative bleeding at the time of CABG, but data are mixed. Numerous studies have conclusively shown that this bleeding risk is confined to those patients receiving clopidogrel within 5 days of CABG. The absolute number of patients exposed to this possible bleeding risk is very small relative to the >1 million patients who present annually with NSTE-ACS and is estimated to be <0.8% of these patients. Recent data have shown that (1) holding clopidogrel for 5 days before CABG is safe in patients with NSTE-ACS and (2) clopidogrel use in patients with NSTE-ACS decreases ischemic events in patients referred for CABG compared to patients who are not given clopidogrel. These data strongly challenge the notion that clopidogrel should be withheld until it is determined if the patient will be referred for CABG.


Assuntos
Síndrome Coronariana Aguda/terapia , Ponte de Artéria Coronária/métodos , Inibidores da Agregação Plaquetária/uso terapêutico , Ticlopidina/análogos & derivados , Síndrome Coronariana Aguda/fisiopatologia , Clopidogrel , Humanos , Ticlopidina/uso terapêutico , Resultado do Tratamento
15.
J Biol Chem ; 284(4): 2080-7, 2009 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-19017630

RESUMO

Overexpression of the receptor tyrosine kinase erbB2 (Her2 in humans) is correlated with a poor prognosis in breast and ovarian cancers. Treatment with trastuzumab (a monoclonal antibody against erbB2) improves survival; however, it also causes cardiomyopathy. We hypothesized that blockade of the erbB2 receptor induces cardiomyocyte death through a mitochondrial pathway that is dependent on the production of reactive oxygen species (ROS). We first showed that levels of erbB2 receptor are significantly decreased in an animal model of ischemic heart disease and in human ischemic cardiomyopathy. We treated neonatal rat cardiomyocytes with an inhibitory erbB2 antibody to study the mechanism behind the deleterious effects of erbB2 blockade. These cells displayed a dose-dependent increase in ROS production and cell death compared with control IgG-treated cells; these processes were reversed by the antioxidant, N-acetylcysteine. The effects of erbB2 antibody on both cell death and ROS production were also reversed by cyclosporine A and diazoxide, chemicals that regulate the pro- and anti-apoptotic channels in the mitochondria, respectively. Furthermore, mouse embryonic fibroblasts lacking Bax and Bak (proteins that mediate cell death through a mitochondrial pathway) were resistant to the deleterious effects of erbB2 antibody. These effects of erbB2 blockade appear to occur through a pathway involving AKT and PKC-alpha. Our results suggest that erbB2 plays a role in cardiomyocyte survival, and that the deleterious effects of trastuzumab on the heart occur through a mitochondrial pathway and is mediated by ROS production. Manipulation of redox signaling may be beneficial in cancer patients receiving trastuzumab.


Assuntos
Mitocôndrias/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Receptor ErbB-2/antagonistas & inibidores , Receptor ErbB-2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Anticorpos/imunologia , Morte Celular , Cães , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Humanos , Mitocôndrias/efeitos dos fármacos , Isquemia Miocárdica/enzimologia , Isquemia Miocárdica/genética , Isquemia Miocárdica/patologia , Miócitos Cardíacos/efeitos dos fármacos , Proteína Quinase C-alfa/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Interferente Pequeno/genética , Receptor ErbB-2/genética , Receptor ErbB-2/imunologia , Fatores de Tempo
16.
Circ Res ; 102(2): 164-76, 2008 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-18239147

RESUMO

ATP-binding cassette (ABC) proteins are highly conserved and widely expressed throughout nature and found in all organisms, both prokaryotic and eukaryotic. They mediate myriad critical cellular processes, from nutrient import to toxin efflux using the energy derived from ATP hydrolysis. Most ABC proteins mediate transport of substances across lipid membranes. However, there are atypical ABC proteins that mediate other processes. These include, but are not limited to, DNA repair (bacterial MutS), ion transport (cystic fibrosis transmembrane receptor), and mRNA trafficking (yeast Elf1p). The sulfonylurea receptor (SUR) is another atypical ABC protein that regulates activity of the potassium ATP channel (K(ATP)). K(ATP) is widely expressed in nearly all tissues of higher organisms and couples cellular energy status to membrane potential. K(ATP) is particularly important in the regulation of insulin secretion from pancreatic beta-cells and in regulating action potential duration in muscle cells. SUR is indispensable for normal channel function, and mutations in genes encoding SURs increase the susceptibility to diabetes, myocardial infarction, and heart failure. Here, we review the structure and function of ABC proteins and discuss SUR, its regulation of the K(ATP) channel, and its role in cardiovascular disease.


Assuntos
Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/fisiologia , Canais KATP/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/química , Canais de Potássio Corretores do Fluxo de Internalização/fisiologia , Canais de Potássio/química , Canais de Potássio/fisiologia , Receptores de Droga/química , Receptores de Droga/fisiologia , Doenças Cardiovasculares , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G , Humanos , Conformação Proteica , Receptores de Sulfonilureias
17.
Heart Fail Rev ; 12(1): 23-36, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17345160

RESUMO

B-Type natriuretic peptide (BNP) is elevated in states of increased ventricular wall stress. BNP is most commonly used to rule out congestive heart failure (CHF) in dyspneic patients. BNP levels are influenced by age, gender and, to a surprisingly large extent, by body mass index (BMI). In addition, it can be elevated in a wide variety of clinical settings with or without CHF. BNP is elevated in other cardiac disease states such as the acute coronary syndromes, diastolic dysfunction, atrial fibrillation (AF), amyloidosis, restrictive cardiomyopathy (RCM), and valvular heart disease. BNP is elevated in non-cardiac diseases such as pulmonary hypertension, chronic obstructive pulmonary disease, pulmonary embolism, and renal failure. BNP is also elevated in the setting of critical illness such as in acute decompensated CHF (ADHF) and sepsis. This variation across clinical settings has significant implications given the increasing frequency with which BNP testing is being performed. It is important for clinicians to understand how to appropriately interpret BNP in light of the comorbidities of individual patients to maximize its clinical utility. We will review the molecular biology and physiology of natriuretic peptides as well as the relevant literature on the utilization of BNP in CHF as well as in other important clinical situations, conditions that are commonly associated with CHF and or dyspnea.


Assuntos
Dispneia/sangue , Cardiopatias/sangue , Peptídeo Natriurético Encefálico/metabolismo , Animais , Biomarcadores , Comorbidade , Estado Terminal , Cardiopatias/metabolismo , Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/metabolismo , Humanos , Pneumopatias/sangue , Peptídeo Natriurético Encefálico/genética , Valor Preditivo dos Testes , Insuficiência Renal/sangue , Sensibilidade e Especificidade
18.
Dev Dyn ; 227(3): 315-22, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12815617

RESUMO

Involution of the mammary gland after weaning occurs in two stages. The first stage is reversible, whereas the second stage is characterized by the irreversible collapse of the alveolar structure. A differential display analysis using cDNAs from tissues obtained at various times after forced weaning of pups identified cathepsin L as up-regulated during early involution. Levels of cathepsin L mRNA were dramatically increased within 24 hr after weaning. Cathepsin L protein detected by immunoblot was also increased during involution, reaching near maximal levels by 36 hr after weaning. In situ immunohistochemistry detected pronounced cathepsin L protein in the cytoplasm and cell periphery. Mice treated with a specific inhibitor of cathepsin L exhibited substantially reduced numbers of apoptotic cells at times up to 72 hr after weaning when compared with untreated animals. The cathepsin L inhibitor did not alter levels of cathepsin L detected in immunoblots or influence molecular weight of the cathepsin L species detected. These data suggest that cathepsin L plays a regulatory role early in the process of mammary gland involution.


Assuntos
Catepsinas/fisiologia , Glândulas Mamárias Animais/crescimento & desenvolvimento , Desmame , Animais , Apoptose , Northern Blotting , Catepsina L , Cisteína Endopeptidases , Citoplasma/metabolismo , DNA Complementar/metabolismo , Feminino , Perfilação da Expressão Gênica , Imuno-Histoquímica , Glândulas Mamárias Animais/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , RNA Mensageiro/metabolismo , Fatores de Tempo , Regulação para Cima
19.
Urol Clin North Am ; 30(2): 295-304, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12735505

RESUMO

The wide-ranging effects of prostate cancer can be an emotional burden to the patient and his family. Recognizing important periods during the diagnosis and treatment that can be particularly stressful, the symptoms indicating patients are at high risk for emotional distress, and the signs and symptoms of emotional distress can encourage improved communication, education, treatment, and referral to minimize the effects of the emotional distress.


Assuntos
Neoplasias da Próstata/psicologia , Neoplasias Ósseas/secundário , Comunicação , Emoções , Humanos , Masculino , Relações Médico-Paciente , Neoplasias da Próstata/patologia , Neoplasias da Próstata/terapia , Qualidade de Vida , Cônjuges , Estresse Psicológico , Incontinência Urinária/etiologia
20.
Cancer ; 94(11): 2923-9, 2002 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-12115380

RESUMO

BACKGROUND: The psychological adaptation to a cancer diagnosis is characterized by significant distress. Although distress levels in cancer patients have been reported to be the highest shortly after diagnosis and before treatment, few attempts have been made to study emotional adjustment during the diagnostic period of prostate cancer patients. This study's purpose was to determine whether differences in distress levels can be attributed to differences in diagnostic status, optimism, and/or coping strategies. METHODS: This study followed patients across 4 weeks, from prebiopsy to 2 weeks postdiagnosis, using these two time points as measurements. Data were collected between 1995 and 1998 at the Miami and Palo Alto VA Medical Center urology clinics. Biopsies were performed on 101 men (ages 46-87) to determine whether prostate cancer was present. These men completed prebiopsy and postdiagnosis questionnaires. RESULTS: Of optimism, coping, and cancer status, the only significant predictor of increased distress at postdiagnosis was dispositional avoidance at prebiopsy for both cancer and noncancer groups. CONCLUSIONS: Although these findings complement other studies linking avoidance with increased distress, the similarities between the cancer and noncancer groups underscore the need to consider both of these groups during the first few weeks of the prostate cancer diagnostic process.


Assuntos
Adaptação Psicológica , Neoplasias da Próstata/psicologia , Idoso , Idoso de 80 Anos ou mais , Biópsia/psicologia , Humanos , Entrevista Psicológica , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Próstata/patologia , Neoplasias da Próstata/patologia , Testes Psicológicos , Qualidade de Vida , Classe Social , Estresse Psicológico , Inquéritos e Questionários
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