A mitotic chromatin phase transition prevents perforation by microtubules.

Dividing eukaryotic cells package extremely long chromosomal DNA molecules into discrete bodies to enable microtubule-mediated transport of one genome copy to each of the newly forming daughter cells1-3. Assembly of mitotic chromosomes involves DNA looping by condensin4-8 and chromatin compaction by global histone deacetylation9-13. Although condensin confers mechanical resistance to spindle pulling forces14-16, it is not known how histone deacetylation affects material properties and, as a consequence, segregation mechanics of mitotic chromosomes. Here we show how global histone deacetylation at the onset of mitosis induces a chromatin-intrinsic phase transition that endows chromosomes with the physical characteristics necessary for their precise movement during cell division. Deacetylation-mediated compaction of chromatin forms a structure dense in negative charge and allows mitotic chromosomes to resist perforation by microtubules as they are pushed to the metaphase plate. By contrast, hyperacetylated mitotic chromosomes lack a defined surface boundary, are frequently perforated by microtubules and are prone to missegregation. Our study highlights the different contributions of DNA loop formation and chromatin phase separation to genome segregation in dividing cells.

Cohesin-mediated DNA loop extrusion resolves sister chromatids in G2 phase.

Genetic information is stored in linear DNA molecules, which are highly folded inside cells. DNA replication along the folded template path yields two sister chromatids that initially occupy the same nuclear region in an intertwined arrangement. Dividing cells must disentangle and condense the sister chromatids into separate bodies such that a microtubule-based spindle can move them to opposite poles. While the spindle-mediated transport of sister chromatids has been studied in detail, the chromosome-intrinsic mechanics presegregating sister chromatids have remained elusive. Here, we show that human sister chromatids resolve extensively already during interphase, in a process dependent on the loop-extruding activity of cohesin, but not that of condensins. Increasing cohesin's looping capability increases sister DNA resolution in interphase nuclei to an extent normally seen only during mitosis, despite the presence of abundant arm cohesion. That cohesin can resolve sister chromatids so extensively in the absence of mitosis-specific activities indicates that DNA loop extrusion is a generic mechanism for segregating replicated genomes, shared across different Structural Maintenance of Chromosomes (SMC) protein complexes in all kingdoms of life.

Conformation of sister chromatids in the replicated human genome.

The three-dimensional organization of the genome supports regulated gene expression, recombination, DNA repair, and chromosome segregation during mitosis. Chromosome conformation capture (Hi-C)1,2 analysis has revealed a complex genomic landscape of internal chromosomal structures in vertebrate cells3-7, but the identical sequence of sister chromatids has made it difficult to determine how they topologically interact in replicated chromosomes. Here we describe sister-chromatid-sensitive Hi-C (scsHi-C), which is based on labelling of nascent DNA with 4-thio-thymidine and nucleoside conversion chemistry. Genome-wide conformation maps of human chromosomes reveal that sister-chromatid pairs interact most frequently at the boundaries of topologically associating domains (TADs). Continuous loading of a dynamic cohesin pool separates sister-chromatid pairs inside TADs and is required to focus sister-chromatid contacts at TAD boundaries. We identified a subset of TADs that are overall highly paired and are characterized by facultative heterochromatin and insulated topological domains that form separately within individual sister chromatids. The rich pattern of sister-chromatid topologies and our scsHi-C technology will make it possible to investigate how physical interactions between identical DNA molecules contribute to DNA repair, gene expression, chromosome segregation, and potentially other biological processes.

Arterial Accesses in Coronary Angiography and Intervention-Review with a Focus on Prognostic Relevance.

Arterial access in coronary angiography has always been an important issue. Convincing prognostic data from large randomized controlled trials (RCTs) in the first place but also safe performance of same-day-discharge after diagnostic and interventional procedures, improved patient comfort and cost-effectiveness led to a paradigm shift from the transfemoral approach (TFA) to the transradial approach (TRA) in several clinical situations. Consequently, today's relevant guidelines recommend a radial-first strategy as default approach. However, there is still strong controversy among interventional cardiologists resulting in delayed spread of the TRA causing significant regional differences. One major critics point is the rate of postprocedural radial artery occlusion (RAO) after using the traditional puncture site at the proximal radial artery (pTRA) which was registered too high in certain centers. A new access using the distal radial artery (dTRA) in the area of the snuff box (SB) and the dorsal box (DB) has been proven to minimize RAO and enabling even complex interventions using 7F guiding catheters. Although, dTRA seems to be an advantageous option, this approach is still not widely used. This review-addressed to beginners and even advanced interventionalists-presents all arterial access routes in interventional cardiology. It focusses on those to be routinely preferred and also on the possibility to guide the puncture with ultrasound. Thereby, the various approaches, including the transulnar (TRU) but also the still relevant TFA approach, are discussed in detail. Thereby, we introduce our philosophy of "radial freedom" and a new classification for TRA.

Applicability and accuracy of pretest probability calculations implemented in the NICE clinical guideline for decision making about imaging in patients with chest pain of recent onset.

OBJECTIVES: To analyse the implementation, applicability and accuracy of the pretest probability calculation provided by NICE clinical guideline 95 for decision making about imaging in patients with chest pain of recent onset. METHODS: The definitions for pretest probability calculation in the original Duke clinical score and the NICE guideline were compared. We also calculated the agreement and disagreement in pretest probability and the resulting imaging and management groups based on individual patient data from the Collaborative Meta-Analysis of Cardiac CT (CoMe-CCT). RESULTS: 4,673 individual patient data from the CoMe-CCT Consortium were analysed. Major differences in definitions in the Duke clinical score and NICE guideline were found for the predictors age and number of risk factors. Pretest probability calculation using guideline criteria was only possible for 30.8 % (1,439/4,673) of patients despite availability of all required data due to ambiguity in guideline definitions for risk factors and age groups. Agreement regarding patient management groups was found in only 70 % (366/523) of patients in whom pretest probability calculation was possible according to both models. CONCLUSIONS: Our results suggest that pretest probability calculation for clinical decision making about cardiac imaging as implemented in the NICE clinical guideline for patients has relevant limitations. KEY POINTS: • Duke clinical score is not implemented correctly in NICE guideline 95. • Pretest probability assessment in NICE guideline 95 is impossible for most patients. • Improved clinical decision making requires accurate pretest probability calculation. • These refinements are essential for appropriate use of cardiac CT.

Correction to: Applicability and accuracy of pretest probability calculations implemented in the NICE clinical guideline for decision making about imaging in patients with chest pain of recent onset.

The original version of this article, published on 19 March 2018, unfortunately contained a mistake. The following correction has therefore been made in the original: The names of the authors Philipp A. Kaufmann, Ronny Ralf Buechel and Bernhard A. Herzog were presented incorrectly.

Transradial Coronary Angiography--Insights to the One-Catheter Concept.

Transradial coronary angiography (TRC) can be performed applying only one catheter fitting into the right and left coronary ostia (R/LCO). In this bicentric study (n = 2953), we analyzed the ostial performance of the Tiger_II_catheter widely used in TRC. Compared to Judkins catheters, the Tiger_II is frequently associated with ostial instability within the LCO but fits better into the RCO-irrespective of tube size. Judkins catheters generally need more peri-procedural contrast and radiation exposure. TRC may be started using a 5F_Tiger_II on the right side in order to be switched to 5F Judkins in case of propable LCO instability.

Systematic genetic analysis of muscle morphogenesis and function in Drosophila.

Systematic genetic approaches have provided deep insight into the molecular and cellular mechanisms that operate in simple unicellular organisms. For multicellular organisms, however, the pleiotropy of gene function has largely restricted such approaches to the study of early embryogenesis. With the availability of genome-wide transgenic RNA interference (RNAi) libraries in Drosophila, it is now possible to perform a systematic genetic dissection of any cell or tissue type at any stage of the lifespan. Here we apply these methods to define the genetic basis for formation and function of the Drosophila muscle. We identify a role in muscle for 2,785 genes, many of which we assign to specific functions in the organization of muscles, myofibrils or sarcomeres. Many of these genes are phylogenetically conserved, including genes implicated in mammalian sarcomere organization and human muscle diseases.

Late enhanced computed tomography in Hypertrophic Cardiomyopathy enables accurate left-ventricular volumetry.

OBJECTIVES: Late enhancement (LE) multi-slice computed tomography (leMDCT) was introduced for the visualization of (intra-) myocardial fibrosis in Hypertrophic Cardiomyopathy (HCM). LE is associated with adverse cardiac events. This analysis focuses on leMDCT derived LV muscle mass (LV-MM) which may be related to LE resulting in LE proportion for potential risk stratification in HCM. METHODS: N=26 HCM-patients underwent leMDCT (64-slice-CT) and cardiovascular magnetic resonance (CMR). In leMDCT iodine contrast (Iopromid, 350 mg/mL; 150mL) was injected 7 minutes before imaging. Reconstructed short cardiac axis views served for planimetry. The study group was divided into three groups of varying LV-contrast. LeMDCT was correlated with CMR. RESULTS: The mean age was 64.2 ± 14 years. The groups of varying contrast differed in weight and body mass index (p < 0.05). In the group with good LV-contrast assessment of LV-MM resulted in 147.4 ± 64.8 g in leMDCT vs. 147.1 ± 65.9 in CMR (p > 0.05). In the group with sufficient contrast LV-MM appeared with 172 ± 30.8 g in leMDCT vs. 165.9 ± 37.8 in CMR (p > 0.05). Overall intra-/inter-observer variability of semiautomatic assessment of LV-MM showed an accuracy of 0.9 ± 8.6 g and 0.8 ± 9.2 g in leMDCT. All leMDCT-measures correlated well with CMR (r > 0.9). CONCLUSIONS: LeMDCT primarily performed for LE-visualization in HCM allows for accurate LV-volumetry including LV-MM in > 90% of the cases. KEY POINTS: • LeMDCT of relatively low contrast allows for LV planimetry in HCM. • The correlation of leMDCT-based LV volumetry with gold-standard CMR was excellent (r > 0.9). • LeMDCT requires approximately 2.0mL/kgBW of dye to achieve acceptable contrast.

Myocardial Fibrosis in Hypertrophic Cardiomyopathy: Volumetric Assessment of Late Enhancement Provided by Cardiac Computed Tomography.

INTRODUCTION: With subgroups of patients with hypertrophic cardiomyopathy (HCM) confers a 4% to 5% risk for adverse prognosis. Besides left-ventricular muscle mass (LV-MM) myocardial fibrosis (MF) assessable by late gadolinium enhancement in cardiovascular magnetic resonance (LGE-CMR) has been related to that. Myocardial fibrosis can also be demonstrated by late enhancement (LE) in late-enhanced multislice computed tomography (leMDCT). This analysis investigates leMDCT whether to enable quantification of LE load in terms of LE mass by percent LV-MM in HCM. METHODS: In a prospective validation study, we included 30 consecutive patients with HCM who underwent leMDCT (64 slice) and LGE-CMR (1.5 T). The leMDCT scan was performed 7 minutes after injection of iodine contrast (Iopromid). Endocardial and epicardial planimetry served for the assessment of LV-MM. Visually detectable LE was quantified using the manual quantification method resulting in LE by percent LV-MM (%LE). The LGE-CMR data served for validation. RESULTS: Mean (SD) age was 64.1 (13.9) years. Myocardial fibrosis prevalence was 63.3% (19/30 patients indentified by both leMDCT and LGE-CMR). In leMDCT, tissue density in LE areas compared with normal myocardium was higher (138.2 [23.9] HU vs 98.4 [16.5] HU, P < 0.001) but lower than in the LV cavity (138.2 [23.9] HU vs 169.2 [35.9] HU, P < 0.001). Late enhancement mass in leMDCT seemed to be 7.9 (8.5) g LE versus 8.6 [11] g LGE in CMR (P = 0.497, r = 0.95) resulting in a leMDCT/LGE-CMR relation of 1.2. Referring LE mass to LV-MM gave an LE proportion measured by leMDCT of 4 (3.9) %LE versus 3.9 (4.1) %LGE in LGE-CMR (r = 0.88, P = 0.75). Intraobserver/interobserver reliability of LE mass assessment showed an intraclass correlation coefficient of 0.99 and 0.97. CONCLUSIONS: In patients with HCM, leMDCT provides volumetric assessment of LE mass-absolutely and by percent LV-MM.

The effectiveness of coronary computed tomography angiography and functional testing for the diagnosis of obstructive coronary artery disease: results from the individual patient data Collaborative Meta-Analysis of Cardiac CT (COME-CCT).

AIM: To determine the effectiveness of functional stress testing and computed tomography angiography (CTA) for diagnosis of obstructive coronary artery disease (CAD). METHODS AND RESULTS: Two-thousand nine-hundred twenty symptomatic stable chest pain patients were included in the international Collaborative Meta-Analysis of Cardiac CT consortium to compare CTA with exercise electrocardiography (exercise-ECG) and single-photon emission computed tomography (SPECT) for diagnosis of CAD defined as ≥ 50% diameter stenosis by invasive coronary angiography (ICA) as reference standard. Generalised linear mixed models were used for calculating the diagnostic accuracy of each diagnostic test including non-diagnostic results as dependent variables in a logistic regression model with random intercepts and slopes. Covariates were the reference standard ICA, the type of diagnostic method, and their interactions. CTA showed significantly better diagnostic performance (p < 0.0001) with a sensitivity of 94.6% (95% CI 92.7-96) and a specificity of 76.3% (72.2-80) compared to exercise-ECG with 54.9% (47.9-61.7) and 60.9% (53.4-66.3), SPECT with 72.9% (65-79.6) and 44.9% (36.8-53.4), respectively. The positive predictive value of CTA was ≥ 50% in patients with a clinical pretest probability of 10% or more while this was the case for ECG and SPECT at pretest probabilities of ≥ 40 and 28%. CTA reliably excluded obstructive CAD with a post-test probability of below 15% in patients with a pretest probability of up to 74%. CONCLUSION: In patients with stable chest pain, CTA is more effective than functional testing for the diagnosis as well as for reliable exclusion of obstructive CAD. CTA should become widely adopted in patients with intermediate pretest probability. SYSTEMATIC REVIEW REGISTRATION: PROSPERO Database for Systematic Reviews-CRD42012002780. CRITICAL RELEVANCE STATEMENT: In symptomatic stable chest pain patients, coronary CTA is more effective than functional testing for diagnosis and reliable exclusion of obstructive CAD in intermediate pretest probability of CAD. KEY POINTS: Coronary computed tomography angiography showed significantly better diagnostic performance (p < 0.0001) for diagnosis of coronary artery disease compared to exercise-ECG and SPECT. The positive predictive value of coronary computed tomography angiography was ≥ 50% in patients with a clinical pretest probability of at least 10%, for ECG ≥ 40%, and for SPECT 28%. Coronary computed tomography angiography reliably excluded obstructive coronary artery disease with a post-test probability of below 15% in patients with a pretest probability of up to 74%.

Elite athletes with mitral or aortic regurgitation and their cardiopulmonary capability.

BACKGROUND: Aortic or mitral valvular regurgitation (left cardiac valvular regurgitation, LCVR) of less than second-degree (< degree II) occasionally found in competitive athletes is of questionable relevance. Precisely detectable by echocardiography there is scarce published data that clarifies cardiopulmonary capacity or any limitations LCVR < degree ll may cause. METHODS: In this single-centre study we consecutively recruited highly trained athletes (n= 14) with LCVR < degree ll detected in 2D echo. Not included were athletes with multi- or right-cardiac valvular dysfunction and structural heart disease other than bicuspid aortic valve or mitral valve prolaps. Target parameters were determined by 2D echo and spiroergometry. RESULTS: There were no significant differences with regard to age and body mass index. Echocardiographically determined muscle mass index was increased in both groups (134 14.7 vs 129.6+/-27.5; P=0.69), whereas the left-ventricular end-diastolic diameter index was significant higher in the LCVR < degree II group (27.3 +/- 1.3 vs 25.2 +/- 2.4; P = 0.04). However, there were no significant differences with regard to (oxygen uptake) V02, at baseline (athletes with LCVR < degree II 5.7 +/- 0.9 vs controls 5 +/- 0.96, P= 0.06), at the anaerobic threshold (athletes with LCVR < degree II 47.3 +/-8.4 vs controls 47.4 +/- 5, P= 0.97) and maximally (VO2max; athletes with LCVR < degree II 57.7 6.3 vs controls 57.1 +/- 5.1, P= 0.81). Neither levels of lactate nor of brain natriuretic peptide differed significantly. CONCLUSION: High level athletes presenting with aortic or mitral regurgitation < degree II in are not disadvantaged with regard to their cardiopulmonary capability.

HiCognition: a visual exploration and hypothesis testing tool for 3D genomics.

Genome browsers facilitate integrated analysis of multiple genomics datasets yet visualize only a few regions at a time and lack statistical functions for extracting meaningful information. We present HiCognition, a visual exploration and machine-learning tool based on a new genomic region set concept, enabling detection of patterns and associations between 3D chromosome conformation and collections of 1D genomics profiles of any type. By revealing how transcription and cohesion subunit isoforms contribute to chromosome conformation, we showcase how the flexible user interface and machine learning tools of HiCognition help to understand the relationship between the structure and function of the genome.

Effects of percutaneous coronary intervention on dyspnea in stable coronary artery disease.

BACKGROUND: Dyspnea is a frequent symptom in patients with stable coronary artery disease (CAD) and is recognized as a possible angina equivalent. OBJECTIVES: This study was to assess the impact of percutaneous coronary intervention (PCI) on dyspnea, quality of life, and angina pectoris in patients with stable CAD. METHODS: The prospective, multi-center PLA-pCi-EBO-pilot trial included 144 patients with symptomatic stable CAD and successful PCI. The prespecified endpoints angina pectoris (Seattle Angina Questionnaire-SAQ) and dyspnea (NYHA scale) were assessed 6 months after PCI. Predictors for symptomatic improvement were assessed with uni- and multivariable logistic regression analyses. RESULTS: Patients with concomitant dyspnea had worse SAQ physical limitation scores at baseline (49.5 ± 21.0 vs 58.9 ± 22.0, p = 0.013) but showed no difference for angina frequency or quality of life. Overall, symptomatic burden of angina pectoris and dyspnea was alleviated by PCI. However, patients with concomitant dyspnea had markedly worse scores for physical limitation (78.9 ± 25.0 vs 94.3 ± 10.6, p < 0.001), angina frequency (77.9 ± 22.8 vs 91.1 ± 12.4, p < 0.001), and quality of life (69.4 ± 24.1 vs 82.5 ± 14.4, p < 0.001) after PCI. The prevalence of dyspnea (NYHA class ≥ 2) declined from 73% before PCI to 54%. Of 95 initially dyspneic patients, 57 (60%) improved at least one NYHA class 6 months after PCI. In a multivariable logistic regression analysis, "atypical angina pectoris" was associated with improved NYHA class, whereas "diabetes mellitus" had a negative association. CONCLUSION: PCI effectively reduced dyspnea, which is a frequent and demanding symptom in patients with CAD. The German Clinical Trials Register registration number is DRKS0001752 ( www.drks.de ).

First-in-man experience with a new 7F vascular closure device (EXOSEAL™): the 7F ECLIPSE study.

OBJECTIVE: This feasibility study examined safety and effectiveness of the new EXOSEAL™ Vascular Closure Device (VCD) designed to promote hemostasis and early ambulation after percutaneous procedures. BACKGROUND: Most VCDs currently approved by the United States FDA have been associated with significantly shorter time-to-hemostasis (TTH) and time-to-ambulation (TTA) compared to standard manual or mechanical compression, but their ease of use, patient comfort during deployment, and safety profiles are variable. METHODS: Patients underwent diagnostic or interventional procedures using 7F introducer sheaths. Primary safety endpoint was the 30-day combined rate of access-related complications and primary effectiveness endpoints were TTH and TTA. RESULTS: Sixty patients were enrolled prospectively (mean age 63.3 ± 11.3 year, 17% diabetics). Device and procedural success was achieved in 92% and 93%, respectively. Mean TTH and TTA was 3.2 ± 3.0 minutes and 3.0 ± 6.2 hours, respectively. No deaths or serious access-related adverse events occurred. A ≥6 cm access-site hematoma was the only adverse event, observed in 3 patients. CONCLUSIONS: Use of the 7F EXOSEAL™ VCD was associated with short TTH and TTA, as well as low rates of procedural and 30-day access-related complications.

Cheyne-Stokes respiration and obstructive sleep apnoea are independent risk factors for malignant ventricular arrhythmias requiring appropriate cardioverter-defibrillator therapies in patients with congestive heart failure.

AIMS: The aim of this first large-scale long-term study was to investigate whether obstructive sleep apnoea (OSA) and/or central sleep apnoea (CSA) are associated with an increased risk of malignant cardiac arrhythmias in patients with congestive heart failure (CHF). METHODS AND RESULTS: Of 472 CHF patients who were screened for sleep disordered breathing (SDB) 6 months after implantation of a cardiac resynchronization device with cardioverter-defibrillator, 283 remained untreated [170 with mild or no sleep disordered breathing (mnSDB) and 113 patients declined ventilation therapy] and were included into this study. During follow-up (48 months), data on appropriately monitored ventricular arrhythmias as well as appropriate cardioverter-defibrillator therapies were obtained from 255 of these patients (90.1%). Time period to first monitored ventricular arrhythmias and to first appropriate cardioverter-defibrillator therapy were significantly shorter in patients with either CSA or OSA. Forward stepwise Cox models revealed an independent correlation for CSA and OSA regarding monitored ventricular arrhythmias [apnoea-hypopnoea index (AHI) ≥5 h(-1): CSA HR 2.15, 95% CI 1.40-3.30, P < 0.001; OSA HR 1.69, 95% CI 1.64-1.75, P = 0.001; AHI ≥15 h(-1): CSA HR 2.06, 95% CI 1.40-3.05, P < 0.001; OSA HR 1.69, 95% CI 1.14-2.51, P = 0.02] and appropriate cardioverter-defibrillator therapies (AHI ≥5 h(-1): CSA HR 3.24, 95% CI 1.86-5.64, P < 0.001; OSA HR 2.07, 95% CI 1.14-3.77, P = 0.02; AHI ≥15 h(-1): CSA HR 3.41, 95% CI 2.10-5.54, P < 0.001; OSA HR 2.10, 95% CI 1.17-3.78, P = 0.01). CONCLUSION: In patients with CHF, CSA and OSA are independently associated with an increased risk for ventricular arrhythmias and appropriate cardioverter-defibrillator therapies.

The occurrence of atrial fibrillation in former top-level handball players above the age of 50.

OBJECTIVE: Cardiac adaptation to sports activity in endurance athletes is considerably different from that in power athletes. The effects of a high-level team sport like handball, one of the most popular sports in the world, performed at a younger age, on cardiac rhythm in individuals above the age of 50 have not been investigated to date. METHODS: Thirty-three former top-level handball players from the first German league (6 former world champions and numerous Olympians) (57.5 +/- 5.5 y) joined our screening programme for former athletes and underwent electrocardiography, echocardiography and spiroergometry. Data were compared to 24 sedentary healthy controls. RESULTS: Ten of the 33 athletes suffered from atrial fibrillation (AF). Left ventricular diameter was 53.68 +/- 4.88 mm in the athletes group and 50.58 +/- 4.12 mm in the healthy controls. Analysing the subgroups of handball players ('AF group' and 'non-AF group'), spiroergometry showed oxygen consumption at the anaerobic threshold of 27.54 +/- 6.77 ml/kg/min in the AF group and 31.24 +/- 10.33 ml/kg/min in the non-AF group (P = 0.228). Absolute left atrial diameter was 44.34 +/- 4.41 mm in the AF group (non-AF group 38.94 +/- 3.77 mm, P < 0.001) (healthy controls 37.54 +/- 4.34 mm, compared with all athletes P = 0.015). In all individuals left ventricular wall thickness was within normal limits. However, myocardial walls were thicker in the AF group (11.28 +/- 1.83 mm) than in the non-AF group (9.44 +/- 1.26 mm, P = 0.002). Athletes in the AF group (187.6 +/- 6.42 cm) were significantly taller than in the non-AF group (180.91 +/- 7.31 cm, P = 0.018). CONCLUSION: Not only endurance training, but also sports activity with a relevant static component, like team handball, might predispose for AF above the age of 50. LA size, height and myocardial wall thickness seem to affect the risk of developing AF. More data in non-endurance sports are mandatory to confirm this hypothesis.

Sister chromatid-sensitive Hi-C to map the conformation of replicated genomes.

Chromosome conformation capture (Hi-C) techniques map the 3D organization of entire genomes. How sister chromatids fold in replicated chromosomes, however, cannot be determined with conventional Hi-C because of the identical DNA sequences of sister chromatids. Here, we present a protocol for sister chromatid-sensitive Hi-C (scsHi-C) that enables the distinction of DNA contacts within individual sister chromatids (cis sister contacts) from those between sister chromatids (trans sister contacts), thereby allowing investigation of the organization of replicated genomes. scsHi-C is based on live-cell labeling of nascent DNA by the synthetic nucleoside 4-thio-thymidine (4sT), which incorporates into a distinct DNA strand on each sister chromatid because of semi-conservative DNA replication. After purification of genomic DNA and in situ Hi-C library preparation, 4sT is chemically converted into 5-methyl-cytosine in the presence of OsO4/NH4Cl to introduce T-to-C signature point mutations on 4sT-labeled DNA. The Hi-C library is then sequenced, and ligated fragments are assigned to sister chromatids on the basis of strand orientation and the presence of signature mutations. The ensemble of scsHi-C contacts thereby represents genome-wide contact probabilities within and across sister chromatids. scsHi-C can be completed in 2 weeks, has been successfully applied in HeLa cells and can potentially be established for any cell type that allows proper cell cycle synchronization and incorporation of sufficient amounts of 4sT. The genome-wide maps of replicated chromosomes detected by scsHi-C enable investigation of the molecular mechanisms shaping sister chromatid topologies and the relevance of sister chromatid conformation in crucial processes like DNA repair, mitotic chromosome formation and potentially other biological processes.

Scanning electron microscopic analysis of different drug eluting stents after failed implantation: from nearly undamaged to major damaged polymers.

BACKGROUND: Implantation of drug eluting stents (DES) in tortuous and/or calcified vessels is much more demanding compared with implantation of bare metal stents (BMS) due to their larger diameters. It is unknown whether drug eluting stent coatings get damaged while crossing these lesions. METHODS: In 42 patients (34 male, 68.1 +/- 10 years) with 45 calcified lesions (15.9 mm +/- 7.9 mm), DES could not be implanted, even after predilatation. Diabetes was present in 19 patients (45%). Sixty-one stents were used; 19 Cypher select, 18 Taxus Liberté, 10 CoStar, 5 Endeavor RX, 4 Xience V. 3 Janus Carbostent, 1 Yukon Choice S, and 1 Axxion DES. The entire accessible surface area of these stents, in either the unexpanded and expanded state, were examined with an environmental scanning electron microscope (XL30 ESEM, Philips) to evaluate polymer or surface damage. RESULTS: The polymers of Taxus Liberte, Cypher Select, Xience V, CoStar, and Janus DES were only slightly damaged (less than 3% of surface area), whereas the Endeavor RX Stents showed up to 20% damaged surface area. In DES without a polymer (Yukon and Axxion), it could be shown that most of the stent surface (up to 40%) were without any layer of drug. CONCLUSION: Placement of drug eluting stents in tortuous vessels and/or calcified lesions could cause major surface damage by scratching and scraping of the polymer or drug by the arterial wall, even before implantation. There were remarkable differences among the stents examined, only minor damage with the Cypher, Taxus Costar, Janus, and Xience V, whereas the Endeavor, the Yukon, and the Janus DES showed large areas of surface injury.

Systolic and early diastolic left ventricular velocities assessed by tissue Doppler imaging in 100 top-level handball players.

BACKGROUND AND OBJECTIVE: Echocardiographic tissue Doppler imaging (TDI) has been proposed for the differentiation of physiologic left ventricular hypertrophy and pathologic left ventricular hypertrophy in athletes. In addition, cutoff values for systolic (S'<9 cm/s) and early diastolic (E'<9 cm/s) myocardial velocities had been defined. The aim of our study was the analysis of the morphologic cardiac changes by standard echocardiography, and the myocardial velocities S' and E' by TDI in top-level handball players with respect to the predefined cutoff values. PATIENTS AND METHODS: Pulsed-wave TDI of the systolic and early diastolic velocities was performed at the lateral and septal mitral annulus (MA) in the four-chamber view in 100 athletes (100 Caucasian men; professional handball players of the first German handball league and the German national team; mean age 25.8+/-4.8 years). RESULTS: Global and regional left ventricular systolic function was normal in all athletes. They showed an eccentric hypertrophy of the left ventricle (LV), which was characterized by an increased mass of the LV (287.3+/-58.4 g), and an increased end diastolic diameter of the LV (LVEDD: 58+/-5.9 mm), but no echomorphologic signs of pathologic hypertrophy or hypertrophic cardiomyopathy. TDI showed a systolic velocity S' of the MA of 9.3+/-1.5 cm/s at the septal and 10.5+/-2.1 at the lateral MA. Ten of the 100 athletes showed a S'<9 cm/s at both sides of the MA. TDI showed an early diastolic velocity E' of the MA of 13.2+/-2.8 cm/s at the septal and of 16.6+/-3.4 cm/s at the lateral MA. None of the 100 athletes showed reduced systolic or early diastolic velocities below the proposed cutoff values (S' and E'<9 cm/s) at any sides of the MA. CONCLUSION: Our study provides further insights into systolic and diastolic function as assessed by TDI in top-level handball players. Owing to the large cohort of individuals, our findings might be helpful as reference values for the echocardiographic assessment of handball players, who are performing a moderate static and high dynamic sport.