The disease mutation A77V in Ryanodine receptor RyR2 induces changes in energy conduction pathways in the protein

Energetically responsive residues of the 217 amino acid N-terminal domain of the cardiac Ryanodine receptor RyR2 are identified by a simple elastic net model. These residues lie along a hydrogen bonded path through the protein. The evolutionarily conserved residues of the protein are all located on this path or in its close proximity. All of the residues of the path are either located on the two Mir domains of the protein or are hydrogen bonded to them. Two calcium binding residues, E171 and E173, are proposed as potential binding residues, based on insights gained from the elastic net analysis of another calcium channel receptor, the inositol 1,4,5-triphosphate receptor, IP3R. Analysis of the disease causing A77V mutated RyR2 showed that the path is disrupted by the loss of energy responsiveness of certain residues

QR in V1 - an ECG sign associated with right ventricular strain and adverse clinical outcome in pulmonary embolism

Aims To test the hypothesis that Qr in V1is a predictor of pulmonary embolism, right ventricular strain, and adverse clinical outcome. Methods and Results ECG's from 151 patients with suspected pulmonary embolism were blindly interpreted by two observers. Echocardiography, troponin I, and pro-brain natriuretic peptide levels were obtained in 75 patients with pulmonary embolism. Qr in V1(14 vs 0 in controls; p<0.0001) and ST elevation in V1≥1mV (15 vs 1 in controls; p=0.0002) were more frequently present in patients with pulmonary embolism. Sensitivity and specificity of Qr in V1and T wave inversion in V2for predicting right ventricular dysfunction were 31/97% and 45/94%, respectively. Three of five patients who died in-hospital and 11 of 20 patients with a complicated course, presented with Qr in V1. After adjustment for right ventricular strain including ECG, echocardiography, pro-brain natriuretic peptide and troponin I levels, Qr in V1(OR 8.7, 95%CI 1.4-56.7; p=0.02) remained an independent predictor of adverse outcome. Conclusions Among the ECG signs seen in patients with acute pulmonary embolism, Qr in V1is closely related to the presence of right ventricular dysfunction, and is an independent predictor of adverse clinical outcom

Assessment of cardiac rejection by MR-imaging and MR-spectroscopy

Background: Detection of cardiac rejection is a major problem in cardiac transplantation. The gold standard is, and remains, endomyocardial biopsy. Purpose: Evaluation of MR-imaging and MR-spectroscopy for detection of cardiac rejection. Methods: Orthotopic cardiac transplantation (HTX) was performed in 13 pigs (body weight 30 kg). All animals obtained immunosuppressive (triple) therapy for 1 week after the operation. Thereafter immunosuppression was stopped to induce cardiac rejection. MRI and MRS (1.5 Tesla General Electrics Signa) were performed pre- and post-operatively on days 10, 17, 24 and 31. The degree of rejection was determined post-operatively using endomyocardial biopsy (Texas grading score). Results: (1) MR-imaging: LV function remained unchanged after HTX. LV mass increased (+42%; P<0.05) with cardiac rejection. (2) MR-spectroscopy: a marked reduction in the ratio of phosphocreatine and adenosine triphosphate, respectively, to inorganic phosphate was observed in the rejecting hearts. (3) Histologic grading confirmed cardiac rejection after stopping immunosuppression. The Texas score was 5.7±0.8 at autopsy. Conclusions: MR-imaging and MR-spectroscopy allow the detection of changes associated with cardiac rejection. Both techniques are correlated with histologic rejection. However, endomyocardial biopsy remains the gold standard for reliable detection of cardiac rejection

Assessment of cardiac rejection by MR-imaging and MR-spectroscopy

Background: Detection of cardiac rejection is a major problem in cardiac transplantation. The gold standard is, and remains, endomyocardial biopsy. Purpose: Evaluation of MR-imaging and MR-spectroscopy for detection of cardiac rejection. Methods: Orthotopic cardiac transplantation (HTX) was performed in 13 pigs (body weight 30 kg). All animals obtained immunosuppressive (triple) therapy for 1 week after the operation. Thereafter immunosuppression was stopped to induce cardiac rejection. MRI and MRS (1.5 Tesla General Electrics Signa) were performed pre- and post-operatively on days 10, 17, 24 and 31. The degree of rejection was determined post-operatively using endomyocardial biopsy (Texas grading score). Results: (1) MR-imaging: LV function remained unchanged after HTX. LV mass increased (+42%; P<0.05) with cardiac rejection. (2) MR-spectroscopy: a marked reduction in the ratio of phosphocreatine and adenosine triphosphate, respectively, to inorganic phosphate was observed in the rejecting hearts. (3) Histologic grading confirmed cardiac rejection after stopping immunosuppression. The Texas score was 5.7±0.8 at autopsy. Conclusions: MR-imaging and MR-spectroscopy allow the detection of changes associated with cardiac rejection. Both techniques are correlated with histologic rejection. However, endomyocardial biopsy remains the gold standard for reliable detection of cardiac rejectio

Percutaneous coronary intervention in Europe 1992-2003

peer reviewedAims: The purpose of this registry is to collect data on trends in interventional cardiology within Europe. Special interest focuses on relative increases and ratios in newer revascularization approaches and its distribution in different regions in Europe. We report the data of the year 2003 and give an overview of the development of coronary interventions since 1992, when the first data collection was performed. Methods and results: Questionnaires were distributed yearly to delegates of all national societies of cardiology represented in the European Society of Cardiology to collect the case numbers of all local institutions and operators. The overall numbers of coronary angiographies increased from 1992 to 2003 from 684,000 to 1,993,000 (from 1,250 to 3,500 per million inhabitants). The respective numbers for percutaneous coronary interventions (PCI-coronary angioplasty) and coronary stenting procedures increased from 184,000 to 733,000 (from 335 to 1,300) and from 3,000 to 610,000 (from 5 to 1,100), respectively. Germany has been the most active country for the past years with 653,000 angiographies (7,800), 222,000 angioplasties (2,500), and 180,000 stenting procedures (2,200) in 2003. The indication has shifted towards acute coronary syndromes, as demonstrated by raising rates of interventions for acute myocardial infarction over the last decade. The procedures are more readily performed and safer, as shown by increasing rate of “ad hoc” PCI and decreasing need for emergency coronary artery bypass surgery (CABG). In 2003, use of drug-eluting stents had further increased. However, an enormous variability is reported with the highest rate in Portugal (55%). Conclusion: Interventional cardiology in Europe is still expanding, mainly but not exclusively due to rapid growth in the eastern European countries. A number of new coronary revascularization procedures introduced over the years have all but disappeared. Only stenting has experienced an exponential growth. The same can be forecast for drug-eluting stenting

Regulation of ryanodine receptor RyR2 by protein-protein interactions: prediction of a PKA binding site on the N-terminal domain of RyR2 and its relation to disease causing mutations [v1; ref status: indexed, http://f1000r.es/4tw]

Protein-protein interactions are the key processes responsible for signaling and function in complex networks. Determining the correct binding partners and predicting the ligand binding sites in the absence of experimental data require predictive models. Hybrid models that combine quantitative atomistic calculations with statistical thermodynamics formulations are valuable tools for bioinformatics predictions. We present a hybrid prediction and analysis model for determining putative binding partners and interpreting the resulting correlations in the yet functionally uncharacterized interactions of the ryanodine RyR2 N-terminal domain. Using extensive docking calculations and libraries of hexameric peptides generated from regulator proteins of the RyR2 channel, we show that the residues 318-323 of protein kinase A, PKA, have a very high affinity for the N-terminal of RyR2. Using a coarse grained Elastic Net Model, we show that the binding site lies at the end of a pathway of evolutionarily conserved residues in RyR2. The two disease causing mutations are also on this path. The program for the prediction of the energetically responsive residues by the Elastic Net Model is freely available on request from the corresponding author

Data of predicted PKA binding sites on RyR2

<p>Highly conserved residues that lie along a path between ALA77, ARG176 and the ligand FKGPGD of PKA are shown. Amplitude for each residue is indicated.</p