Microarray analysis reveals a major direct role of DNA copy number alteration in the transcriptional program of human breast tumors

Genomic DNA copy number alterations are key genetic events in the development and progression of human cancers. Here we report a genome-wide microarray comparative genomic hybridization (array CGH) analysis of DNA copy number variation in a series of primary human breast tumors. We have profiled DNA copy number alteration across 6,691 mapped human genes, in 44 predominantly advanced, primary breast tumors and 10 breast cancer cell lines. While the overall patterns of DNA amplification and deletion corroborate previous cytogenetic studies, the high-resolution (gene-by-gene) mapping of amplicon boundaries and the quantitative analysis of amplicon shape provide significant improvement in the localization of candidate oncogenes. Parallel microarray measurements of mRNA levels reveal the remarkable degree to which variation in gene copy number contributes to variation in gene expression in tumor cells. Specifically, we find that 62% of highly amplified genes show moderately or highly elevated expression, that DNA copy number influences gene expression across a wide range of DNA copy number alterations (deletion, low-, mid- and high-level amplification), that on average, a 2-fold change in DNA copy number is associated with a corresponding 1.5-fold change in mRNA levels, and that overall, at least 12% of all the variation in gene expression among the breast tumors is directly attributable to underlying variation in gene copy number. These findings provide evidence that widespread DNA copy number alteration can lead directly to global deregulation of gene expression, which may contribute to the development or progression of cancer.     

Safety and efficacy of radiofrequency energy catheter ablation of atrial fibrillation in patients with pacemakers and implantable cardiac defibrillators

BACKGROUND: Catheter ablation has significantly transformed the clinical management of atrial fibrillation (AF). The safety and efficacy of this procedure are not well understood in patients with pacemakers and defibrillators. OBJECTIVES: The purpose of this study was to study the impact of radiofrequency catheter ablation of AF in patients with pacemakers and implantable cardiac defibrillators. METHODS: We studied 86 patients with pacemakers and defibrillators (group I) and a similar number of age- and gender-matched controls (group II) who underwent AF ablation between 1999 and 2004. Clinical and procedural variables were compared between the two groups. In group I, various generator and lead parameters were compared before and after the procedure. Resurgence of clinical AF after 2 months was considered recurrence. RESULTS: Both groups were similar with regard to age, gender, body mass index, and type of AF. Group I had a higher incidence of diabetes (17% vs 6%, P = .03), coronary artery disease (25% vs 13%, P = .05), less prolonged AF (31 +/- 21 vs 45 +/- 30 months, P <.001), lower left ventricular ejection fraction (49 +/- 13% vs 52 +/- 9%, P = .03), and left ventricular end-diastolic dimensions (4.97 +/- 0.81 vs 4.72 +/- 0.67, P = .03). No changes in the sensing and pacing thresholds, impedance of atrial and ventricular leads, or defibrillator coil impedance after AF ablation were observed in group I. Atrial lead dislodgment was seen in two patients. Transient abnormal but "expected" pulse generator behavior was seen in 25% of patients without permanent malfunction. Stroke (1% vs 1%, P = 1.000), pulmonary vein stenosis (2% vs 1%, P = .77), and AF recurrence rates at 12 months were similar between groups I and II, respectively (19% vs 21%, P = .73). CONCLUSION: AF ablation is safe and efficacious in patients with pacemakers and defibrillators.     

G-protein-coupled receptor kinase activity in human heart failure: effects of beta-adrenoceptor blockade

OBJECTIVES: In human end-stage heart failure as well as in experimental animal models of heart failure, G-protein-coupled receptor kinase activity (GRK) is increased while beta-adrenoceptor responsiveness is diminished. In animal studies, beta-adrenoceptor blockers reverse the GRK-mediated desensitization and down-regulation of myocardial beta-adrenoceptors. The aim of this study was to investigate whether alterations in GRK activity are an early or late accompaniment of human heart failure and whether also in humans beta-adrenoceptor blocker treatment is able to influence myocardial GRK activity. METHODS: We assessed in right atria, obtained from patients at different stages of heart failure, treated with or not treated with beta-adrenoceptor blockers, and in the four chambers of explanted hearts, obtained from patients with end-stage heart failure, beta-adrenoceptor density (by (-)-[(125)I]-iodocyanopindolol binding) and GRK activity (by an in vitro rhodopsin phosphorylation assay). RESULTS: With increasing severity of heart failure, plasma noradrenaline levels increased while myocardial beta-adrenoceptor density decreased with a maximum in GRK activity in end-stage heart failure. However, in relation to the progression of heart failure, we found that GRK activity transiently increased at an early stage of heart failure (NYHA I and II) but decreased back to control values in patients at NYHA III and IV. beta-Adrenoceptor blockers were able to reduce the early increase in GRK activity at NYHA I and II to control levels, whereas in those patients who did not have increased GRK activity (NYHA III and IV), they had only a marginal effect. CONCLUSION: According to our results, an increase in GRK activity is an early and transient event in the course of heart failure that can be prevented by beta-adrenoceptor blocker treatment.     

Fractional Flow Reserve Derived From Computed Tomographic Angiography in Patients With Multivessel CAD

Background

The functional SYNTAX score (FSS) has been shown to improve the discrimination for major adverse cardiac events compared with the anatomic SYNTAX score (SS) while reducing interobserver variability. However, evidence supporting the noninvasive FSS in patients with multivessel coronary artery disease (CAD) is scarce.

Validation of Prosthetic Mitral Regurgitation Quantification Using Novel Angiographic Platform by Mock Circulation

ObjectivesThis study aimed to validate a dedicated software for quantitative videodensitometric angiographic assessment of mitral regurgitation (QMR).BackgroundQuantitative videodensitometric aortography of aortic regurgitation using the time-density principle is a well-documented technique, but the angiographic assessment of mitral regurgitation (MR) remains at best semi-quantitative and operator dependent.MethodsFourteen sheep underwent surgical mitral valve replacement using 2 different prostheses. Pre-sacrifice left ventriculograms were used to assess MR fraction (MRF) using QMR and MR volume (MRV). In an independent core lab, the CAAS QMR 0.1 was used for QMR analysis. In vitro MRF and MRV were assessed in a mock circulation at a comparable cardiac output to the in vivo one by thermodilution. The correlations and agreements of in vitro and in vivo MRF, MRV, and interobserver reproducibility for QMR analysis were assessed using the averaged cardiac cycles (CCs).ResultsIn vivo derived MRF by QMR strongly correlated with in vitro derived MRF, regardless of the number of the CCs analyzed (best correlation: 3 CCs y = 0.446 + 0.994x; R = 0.784; p =0.002). The mean absolute difference between in vitro derived MRF and in vivo derived MRF from 3 CCs was 0.01 ± 4.2% on Bland-Altman analysis. In vitro MRV and in vivo MRV from 3 CCs were very strongly correlated (y = 0.196 + 1.255x; R = 0.839; p < 0.001). The mean absolute difference between in vitro MRV and in vivo MRV from 3 CCs was –1.4 ± 1.9 ml. There were very strong correlations of in vivo MRF between 2 independent analysts, regardless of the number of the CCs.ConclusionsIn vivo MRF using the novel software is feasible, accurate, and highly reproducible. These promising results have led us to initiate the first human feasibility study comprising patients undergoing percutaneous mitral valve edge-to-edge repair.     

Comparison of effects on low-density lipoprotein cholesterol and high-density lipoprotein cholesterol with rosuvastatin versus atorvastatin in patients with type IIa or IIb hypercholesterolemia.

This randomized, double-blind, placebo-controlled trial was conducted in 52 centers in North America to compare the effects of the new, highly effective statin, rosuvastatin, with atorvastatin and placebo in hypercholesterolemic patients. After a 6-week dietary run-in, 516 patients with low-density lipoprotein (LDL) cholesterol > or =4.14 mmol/L (160 mg/dl) and < 6.47 mmol/L (250 mg/dl) and triglycerides < or =4.52 mmol/L (400 mg/dl) were randomized to 12 weeks of once-daily placebo (n = 132), rosuvastatin 5 mg (n = 128), rosuvastatin 10 mg (n = 129), or atorvastatin 10 mg (n = 127). The primary efficacy end point was percent change in LDL cholesterol. Secondary efficacy variables were achievement of National Cholesterol Education Program (NCEP) Adult Treatment Panel II (ATP II), ATP III, and European Atherosclerosis Society LDL cholesterol goals and percent change from baseline in high-density lipoprotein (HDL) cholesterol, total cholesterol, triglycerides, non-HDL cholesterol, apolipoprotein B, and apolipoprotein A-I. Rosuvastatin 5 and 10 mg compared with atorvastatin 10 mg were associated with greater LDL cholesterol reductions (-40% and -43% vs 35%; p <0.01 and p <0.001, respectively) and HDL cholesterol increases (13% and 12% vs 8%, p <0.01 and p <0.05, respectively). Total cholesterol and apolipoprotein B reductions and apolipoprotein A-I increases were also greater with rosuvastatin; triglyceride reductions were similar. Rosuvastatin 5 and 10 mg were associated with improved achievement in ATP II (84% in both rosuvastatin groups vs 73%) and ATP III (84% and 82% vs 72%) LDL cholesterol goals, and rosuvastatin 10 mg was more effective than atorvastatin in achieving European Atherosclerosis Society LDL cholesterol goals. Both treatments were well tolerated.     

Tyrosines 559 and 807 in the cytoplasmic tail of the macrophage colony-stimulating factor receptor play distinct roles in osteoclast differentiation and function

Osteoclast (OC) differentiation requires that precursors, such as macrophage colony-stimulating factor (M-CSF)-dependent bone marrow macrophages, receive signals transduced by receptor activator of nuclear factor kappaB (RANK) and c-Fms, receptors for RANK ligand (RANKL) and M-CSF, respectively. Activated c-Fms autophosphorylates cytoplasmic tail tyrosine residues, which, by recruiting adaptor molecules, initiate specific signaling pathways. To identify which tyrosine residues are involved in c-Fms signaling in primary cells, we retrovirally transduced M-CSF-dependent bone marrow macrophages with a chimera comprising the external domain of the erythropoietin (Epo) receptor linked to the transmembrane and cytoplasmic domains of c-Fms. Transduced cells differentiate into bone-resorbing osteoclasts when treated with RANKL and either M-CSF or Epo, confirming that both endogenous and chimeric receptors transmit osteoclastogenic signals. Cells expressing chimeric receptors with Y(697)F, Y(706)F, Y(721)F, and Y(921)F single point mutations generate normal numbers of bone-resorbing OCs, with normal bone-resorbing activity when treated with RANKL and Epo. In contrast, those expressing Y(559)F generate fewer OCs, whereas theY807F mutant is incapable of osteoclastogenesis. Finally, although mature OCs expressing Y(559)F exhibit impaired bone resorption, those bearing Y807F do not. Thus, we have identified specific tyrosine residues in the cytoplasmic tail of c-Fms that are critical for transmitting M-CSF-initiated signals individually required for OC formation or function, respectively.     

Managing and recognizing complications after treatment of acromioclavicular joint repair or reconstruction

Complications of the acromioclavicular joint injuries can occur as a result of the injury itself, conservative management, or surgical treatment. Fortunately, the majority of acromioclavicular surgeries utilizing modern techniques and instrumentation result in successful outcomes. However, clinical failures do occur with frequency. The ability to identify the causative factor of failures makes revision surgery more likely to be successful. The purposes of this review are to highlight common problems that can occur following acromioclavicular joint surgery and discuss techniques that can be utilized in revision surgery.