Emergency Department Chest Pain Patients With or Without Ongoing Pain: Characteristics, Outcome, and Diagnostic Value of the Electrocardiogram.

BACKGROUND: In emergency department (ED) chest pain patients, it is believed that the diagnostic accuracy of the electrocardiogram (ECG) for acute coronary syndrome (ACS) is higher during ongoing than abated chest pain. OBJECTIVES: We compared patient characteristics and the diagnostic performance of the ECG in ED patients presenting with ongoing, vs. abated, chest pain. METHODS: In total, 1132 unselected ED chest pain patients were analyzed. The patient characteristics and diagnostic accuracy for index visit ACS of the emergency physicians' interpretation of the ECG was compared in patients with and without ongoing chest pain. Logistic regression analysis was performed to control for possible confounders. RESULTS: Patients with abated chest pain (n = 508) were older, had more comorbidities, and had double the risk of index visit ACS (15%) and major adverse cardiac events (MACE) at 30 days (15.6%) compared with patients with ongoing pain (n = 631; ACS 7.3%, 30-day MACE 7.4%). Sensitivity of the ECG for ACS was 24% in patients with ongoing pain and 35% in those without, specificity was 97% in both groups, negative predictive value was 94% and 89%, respectively, and positive likelihood ratio 10.6 and 7.8, respectively. When the diagnostic performance was controlled for confounders, there was no significant difference between the groups. CONCLUSION: Our results indicate that ED chest pain patients with ongoing pain at arrival are younger, healthier, and have less ACS and 30-day MACE than patients with abated pain, but that there is no difference in the diagnostic accuracy of the ECG for ACS between the two groups.

ABC om - Förmaksflimmer på akuten.

The ABC of atrial fibrillation at the emergency care department Atrial fibrillation (AF) is the most common tachyarrhythmia. When handling patients with AF at the emergency care department it is of utmost importance to take a structural approach, make the right diagnosis, take care of the risk and/or trigger factors, treat and make sure there is an adequate follow-up.

Intratumour diversity of chromosome copy numbers in neuroblastoma mediated by on-going chromosome loss from a polyploid state.

Neuroblastomas (NBs) are tumours of the sympathetic nervous system accounting for 8-10% of paediatric cancers. NBs exhibit extensive intertumour genetic heterogeneity, but their extent of intratumour genetic diversity has remained unexplored. We aimed to assess intratumour genetic variation in NBs with a focus on whole chromosome changes and their underlying mechanism. Allelic ratios obtained by SNP-array data from 30 aneuploid primary NBs and NB cell lines were used to quantify the size of clones harbouring specific genomic imbalances. In 13 cases, this was supplemented by fluorescence in situ hybridisation to assess copy number diversity in detail. Computer simulations of different mitotic segregation errors, single cell cloning, analysis of mitotic figures, and time lapse imaging of dividing NB cells were used to infer the most likely mechanism behind intratumour variation in chromosome number. Combined SNP array and FISH analyses showed that all cases exhibited higher inter-cellular copy number variation than non-neoplastic control tissue, with up to 75% of tumour cells showing non-modal chromosome copy numbers. Comparisons of copy number profiles, resulting from simulations of different segregation errors to genomic profiles of 120 NBs indicated that loss of chromosomes from a tetraploid state was more likely than other mechanisms to explain numerical aberrations in NB. This was supported by a high frequency of lagging chromosomes at anaphase and polyploidisation events in growing NB cells. The dynamic nature of numerical aberrations was corroborated further by detecting substantial copy number diversity in cell populations grown from single NB cells. We conclude that aneuploid NBs typically show extensive intratumour chromosome copy number diversity, and that this phenomenon is most likely explained by continuous loss of chromosomes from a polyploid state.

Alternative lengthening of telomeres--an enhanced chromosomal instability in aggressive non-MYCN amplified and telomere elongated neuroblastomas.

Telomere length alterations are known to cause genomic instability and influence clinical course in several tumor types, but have been little investigated in neuroblastoma (NB), one of the most common childhood tumors. In the present study, telomere-dependent chromosomal instability and telomere length were determined in six NB cell lines and fifty tumor biopsies. The alternative lengthening of telomeres (ALT) pathway was assayed by scoring ALT-associated promyelocytic leukemia (PML) bodies (APBs). We found a reduced probability of overall survival for tumors with increased telomere length compared to cases with reduced or unchanged telomere length. In non-MYCN amplified tumors, a reduced or unchanged telomere length was associated with 100% overall survival. Tumor cells with increased telomere length had an elevated frequency of APBs, consistent with activation of the ALT pathway. The vast majority of tumor biopsies and cell lines exhibited an elevated rate of anaphase bridges, suggesting telomere-dependent chromosomal instability. This was more pronounced in tumors with increased telomere length. In cell lines, there was a close correlation between lack of telomere-protective TTAGGG-repeats, anaphase bridging, and remodeling of oncogene sequences. Thus, telomere-dependent chromosomal instability is highly prevalent in NB, and may contribute to the complexity of genomic alterations as well as therapy resistance in the absence of MYCN amplification and in this tumor type.

Binomial mitotic segregation of MYCN-carrying double minutes in neuroblastoma illustrates the role of randomness in oncogene amplification.

BACKGROUND: Amplification of the oncogene MYCN in double minutes (DMs) is a common finding in neuroblastoma (NB). Because DMs lack centromeric sequences it has been unclear how NB cells retain and amplify extrachromosomal MYCN copies during tumour development. PRINCIPAL FINDINGS: We show that MYCN-carrying DMs in NB cells translocate from the nuclear interior to the periphery of the condensing chromatin at transition from interphase to prophase and are preferentially located adjacent to the telomere repeat sequences of the chromosomes throughout cell division. However, DM segregation was not affected by disruption of the telosome nucleoprotein complex and DMs readily migrated from human to murine chromatin in human/mouse cell hybrids, indicating that they do not bind to specific positional elements in human chromosomes. Scoring DM copy-numbers in ana/telophase cells revealed that DM segregation could be closely approximated by a binomial random distribution. Colony-forming assay demonstrated a strong growth-advantage for NB cells with high DM (MYCN) copy-numbers, compared to NB cells with lower copy-numbers. In fact, the overall distribution of DMs in growing NB cell populations could be readily reproduced by a mathematical model assuming binomial segregation at cell division combined with a proliferative advantage for cells with high DM copy-numbers. CONCLUSION: Binomial segregation at cell division explains the high degree of MYCN copy-number variability in NB. Our findings also provide a proof-of-principle for oncogene amplification through creation of genetic diversity by random events followed by Darwinian selection.

Distinct evolutionary mechanisms for genomic imbalances in high-risk and low-risk neuroblastomas.

BACKGROUND: Neuroblastoma (NB) is the most common extracranial solid tumour of childhood. Several genomic imbalances correlate to prognosis in NB, with structural rearrangements, including gene amplification, in a near-diploid setting typically signifying high-risk tumours and numerical changes in a near-triploid setting signifying low-risk tumours. Little is known about the temporal sequence in which these imbalances occur during the carcinogenic process. METHODS: We have reconstructed the appearance of cytogenetic imbalances in 270 NBs by first grouping tumours and imbalances through principal component analysis and then using the number of imbalances in each tumour as an indicator of evolutionary progression. RESULTS: Tumours clustered in four sub-groups, dominated respectively by (1) gene amplification in double minute chromosomes and few other aberrations, (2) gene amplification and loss of 1p sequences, (3) loss of 1p and other structural aberrations including gain of 17q, and (4) whole-chromosome gains and losses. Temporal analysis showed that the structural changes in groups 1-3 were acquired in a step-wise fashion, with loss of 1p sequences and the emergence of double minute chromosomes as the earliest cytogenetic events. In contrast, the gains and losses of whole chromosomes in group 4 occurred through multiple simultaneous events leading to a near-triploid chromosome number. CONCLUSION: The finding of different temporal patterns for the acquisition of genomic imbalances in high-risk and low-risk NBs lends strong support to the hypothesis that these tumours are biologically diverse entities, evolving through distinct genetic mechanisms.