Cardiac arrest as a reportable condition: a cohort study of the first 6 years of the Norwegian out-of-hospital cardiac arrest registry.

OBJECTIVES: The Norwegian Cardiac Arrest Registry (NorCAR) was established in 2013 when cardiac arrest became a mandatory reportable condition. The aim of this cohort study is to describe how the world's first mandatory, population-based cardiac arrest registry evolved during its first 6 years. SETTING: Norway has a total population of 5.3 million inhabitants with a population density that varies considerably. All residents are assigned a unique identifier number, giving nationally approved registries access to information about all births and deaths in the country. Data in the registry are entered by data processors; public employees with close links to the emergency medical services. All data processors undergo a standardised training and meet for yearly retraining and updates. PARTICIPANTS: All events of cardiac arrest where bystanders or healthcare professionals have started cardiopulmonary resuscitation or performed defibrillation are included into the NorCAR. PRIMARY AND SECONDARY OUTCOME MEASURES: Since the establishment of the registry, the number of reporting health trusts, the number of reported events and the corresponding population at risk were followed year by year. Outcome is measured as changes in inclusion rate, incidence per 100 000 inhabitants and survival to 30 days after cardiac arrest. RESULTS: In total, 14 849 cases were registered over 6 years, between 2013 and 2018. The number of health trusts reporting rose steadily from 2013. Within 3 years, all trusts reported to the registry with an increasing number of events reported; going from 1101 to 3400 per year. The prevalence of bystander cardiopulmonary resuscitation increased slightly, but the population incidence of survival did not change. CONCLUSION: Declaring cardiac arrest as a reportable condition and close follow-up of all reporting areas is essential when building a national registry.

Calculating the 30-day Survival Rate in Acute Myocardial Infarction: Should we Use the Treatment Chain or the Hospital Catchment Model?

INTRODUCTION: Acute myocardial infarction (AMI) is a potentially deadly disease and significant efforts have been concentrated on improving hospital performance. A 30-day survival rate has become a key quality of care indicator. In Northern Norway, some patients undergoing AMI are directly transferred to the Regional Cardiac Intervention Center at the University Hospital of North Norway in Tromsø. Here, coronary angiography and percutaneous coronary intervention is performed. Consequently, local hospitals may be bypassed in the treatment chain, generating differences in case mix, and making the treatment chain model difficult to interpret. We aimed to compare the treatment chain model with an alternative based on patients' place of living. METHODS: Between 2013 and 2015, a total of 3,155 patients were registered in the Norwegian Patient Registry database. All patients were categorized according to their local hospital's catchment area. The method of Guo-Romano, with an indifference interval of 0.02, was used to test whether a hospital was an outlier or not. We adjusted for age, sex, comorbidity, and number of prior hospitalizations. CONCLUSIONS: We revealed the 30-day AMI survival figure ranging between 88.0% and 93.5% (absolute difference 5.5%) using the hospital catchment method. The treatment chain rate ranged between 86.0% and 94.0% (absolute difference 8.0%). The latter figure is the one published as the National Quality of Care Measure in Norway. Local hospitals may get negative attention even though their catchment area is well served. We recommend the hospital catchment method as the first choice when measuring equality of care.

Planar cell polarity gene expression correlates with tumor cell viability and prognostic outcome in neuroblastoma.

BACKGROUND: The non-canonical Wnt/Planar cell polarity (PCP) signaling pathway is a major player in cell migration during embryonal development and has recently been implicated in tumorigenesis. METHODS: Transfections with cDNA plasmids or siRNA were used to increase and suppress Prickle1 and Vangl2 expression in neuroblastoma cells and in non-tumorigenic cells. Cell viability was measured by trypan blue exclusion and protein expression was determined with western blotting. Transcriptional activity was studied with luciferase reporter assay and mRNA expression with real-time RT-PCR. Immunofluorescence stainings were used to study the effects of Vangl2 overexpression in non-tumorigenic embryonic cells. Statistical significance was tested with t-test or one-way ANOVA. RESULTS: Here we show that high expression of the PCP core genes Prickle1 and Vangl2 is associated with low-risk neuroblastoma, suppression of neuroblastoma cell growth and decreased Wnt/ß-catenin signaling. Inhibition of Rho-associated kinases (ROCKs) that are important in mediating non-canonical Wnt signaling resulted in increased expression of Prickle1 and inhibition of ß-catenin activity in neuroblastoma cells. In contrast, overexpression of Vangl2 in MYC immortalized neural stem cells induced accumulation of active ß-catenin and decreased the neural differentiation marker Tuj1. Similarly, genetically modified mice with forced overexpression of Vangl2 in nestin-positive cells showed decreased Tuj1 differentiation marker during embryonal development. CONCLUSIONS: Our experimental data demonstrate that high expression of Prickle1 and Vangl2 reduce the growth of neuroblastoma cells and indicate different roles of PCP proteins in tumorigenic cells compared to normal cells. These results suggest that the activity of the non-canonical Wnt/PCP signaling pathway is important for neuroblastoma development and that manipulation of the Wnt/PCP pathway provides a possible therapy for neuroblastoma.

Exosome-like Extracellular Vesicles from MYCN-amplified Neuroblastoma Cells Contain Oncogenic miRNAs.

BACKGROUND: In recent years, evidence has accumulated indicating that both normal and cancer cells communicate via the release and delivery of macromolecules packed into extracellular membrane vesicles. MATERIALS AND METHODS: We isolated nano-sized extracellular vesicles from MYCN-amplified neuroblastoma cell lines using ultracentrifugation and exosome precipitation (Exoquick) protocols. These vesicles were characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis and western blotting. Exosomal miRNA profiles were obtained using a reverse transcription-polymerase chain reaction (RT-PCR) ready-to-use panel measuring a total of 742 miRNAs. RESULTS: In this study, we showed that MYCN-amplified neuroblastoma cell lines secrete populations of miRNAs inside small exosome-like vesicular particles. These particles were shown to be taken-up by recipient cells. By profiling the miRNA content, we demonstrated high expression of a group of established oncomirs in exosomes from two MYCN-amplified neuroblastoma cell lines. Despite the fact that other studies have demonstrated the ability of exosomal miRNAs both to repress mRNA targets and to stimulate Toll-like receptor-8 (TLR8) signaling in recipient cells, we did not observe these effects with exosomes from MYCN-amplified neuroblastoma cells. However, functional enrichment analysis reveals that mRNA targets of highly expressed exosomal miRNAs are associated with a range of cellular and molecular functions related to cell growth and cell death. CONCLUSION: MYCN-amplified neuroblastoma cell lines secrete exosome-like particles containing oncogenic miRNAs. This work showed for the first time that neuroblastoma cells secrete exosome-like particles containing miRNAs with potential roles in cancer progression. These findings indicate a new way for MYCN-amplified neuroblastoma cells to interact with the tumor environment.

Pacemaker implantation in small hospitals: complication rates comparable to larger centres.

AIMS: Some countries have a demography that makes it necessary to maintain relatively small pacemaker centres. We wanted to assess the quality of pacemaker surgery in two such hospitals. METHODS AND RESULTS: Through patient records we gathered information on ∼535 consecutive primary pacemaker implantations in two small pacemaker centres with 30 and 80 annual operations, respectively. All patients were followed for 3 years. All complications documented in the patient records were registered. Furthermore, we performed a non-systematic literature search comparing our data with reports from major centres published over the last 10 years.We found 72 complications in 64 (12.0%) of the patients, the most common being bleeding, lead failure, and pneumothorax. If minor bleedings without any consequences for the patients are excluded, the number of complications was 46 in 40 patients (7.5%). We had to reoperate on 5.2% of the patients. There was no statistically significant difference in complication rates between the two hospitals. Education candidates generated statistically significant more complications than experienced doctors (13.7 vs. 7.1%, P < 0.05). CONCLUSION: There are no generally accepted norms of complication rates in pacemaker surgery. However, we found no indications that our centres have a rate of complications that is unacceptably high.

MYCN-regulated miRNA-92 inhibits secretion of the tumor suppressor DICKKOPF-3 (DKK3) in neuroblastoma.

The MYCN oncogene is frequently amplified in neuroblastoma. It is one of the most consistent markers of bad prognosis for this disease. Dickkopf-3 (DKK3) is a secreted protein of the DKK family of Wnt regulators. It functions as a tumor suppressor in a range of cancers, including neuroblastoma. MYCN was recently found to downregulate DKK3 mRNA. In this study, we show that MYCN knockdown in MYCN-amplified (MNA) neuroblastoma cell lines increases secretion of endogenous DKK3 to the culture media. MicroRNAs (miRNAs) are ∼20 nt long single-stranded RNA molecules that downregulate messenger RNAs by targeting the 3' untranslated region (3'UTR). Many miRNAs regulate genes involved in the pathogenesis of cancer and are extensively deregulated in different tumors. Using miRNA target prediction software, we found several MYCN-regulated miRNAs that could target the 3'UTR sequence of DKK3, including mir-92a, mir-92b and let-7e. Luciferase expression from a reporter vector containing the DKK3-3'UTR was decreased when this construct was cotransfected with mir-92a, mir-92b or let-7e in HEK293 cells. Mutation of the mir-92 seed sequence in the 3'UTR completely rescued the observed decrease in reporter expression when cotransfected with mir-92a and mir-92b. Antagomir and miRNA-mimic transfections in neuroblastoma cell lines confirmed that DKK3 secretion to the culture media is regulated by mir-92. Consistent with reports from other cancers, we found DKK3 to be expressed in the endothelium of primary neuroblastoma samples and to be absent in tumors with MYCN amplification. Our data demonstrate that MYCN-regulated miRNAs are able to modulate the expression of the tumor suppressor DKK3 in neuroblastoma.

Conditional expression of retrovirally delivered anti-MYCN shRNA as an in vitro model system to study neuronal differentiation in MYCN-amplified neuroblastoma.

BACKGROUND: Neuroblastoma is a childhood cancer derived from immature cells of the sympathetic nervous system. The disease is clinically heterogeneous, ranging from neuronal differentiated benign ganglioneuromas to aggressive metastatic tumours with poor prognosis. Amplification of the MYCN oncogene is a well established poor prognostic factor found in up to 40% of high risk neuroblastomas.Using neuroblastoma cell lines to study neuronal differentiation in vitro is now well established. Several protocols, including exposure to various agents and growth factors, will differentiate neuroblastoma cell lines into neuron-like cells. These cells are characterized by a neuronal morphology with long extensively branched neurites and expression of several neurospecific markers. RESULTS: In this study we use retrovirally delivered inducible short-hairpin RNA (shRNA) modules to knock down MYCN expression in MYCN-amplified (MNA) neuroblastoma cell lines. By addition of the inducer doxycycline, we show that the Kelly and SK-N-BE(2) neuroblastoma cell lines efficiently differentiate into neuron-like cells with an extensive network of neurites. These cells are further characterized by increased expression of the neuronal differentiation markers NFL and GAP43. In addition, we show that induced expression of retrovirally delivered anti-MYCN shRNA inhibits cell proliferation by increasing the fraction of MNA neuroblastoma cells in the G1 phase of the cell cycle and that the clonogenic growth potential of these cells was also dramatically reduced. CONCLUSION: We have developed an efficient MYCN-knockdown in vitro model system to study neuronal differentiation in MNA neuroblastomas.

Inhibition of mir-21, which is up-regulated during MYCN knockdown-mediated differentiation, does not prevent differentiation of neuroblastoma cells.

BACKGROUND: Neuroblastoma is a malignant childhood tumour arising from precursor cells of the sympathetic nervous system. Genomic amplification of the MYCN oncogene is associated with dismal prognosis. For this group of high-risk tumours, the induction of tumour cell differentiation is part of current treatment protocols. MicroRNAs (miRNAs) are small non-coding RNA molecules that effectively reduce the translation of target mRNAs. MiRNAs play an important role in cell proliferation, apoptosis, differentiation and cancer. In this study, we investigated the role of N-myc on miRNA expression in MYCN-amplified neuroblastoma. We performed a miRNA profiling study on SK-N-BE (2) cells, and determined differentially expressed miRNAs during differentiation initiated by MYCN knockdown, using anti-MYCN short-hairpin RNA (shRNA) technology. RESULTS: Microarray analyses revealed 23 miRNAs differentially expressed during the MYCN knockdown-mediated neuronal differentiation of MNA neuroblastoma cells. The expression changes were bidirectional, with 11 and 12 miRNAs being up- and down-regulated, respectively. Among the down-regulated miRNAs, we found several members of the mir-17 family of miRNAs. Mir-21, an established oncomir in a variety of cancer types, became strongly up-regulated upon MYCN knockdown and the subsequent differentiation. Neither overexpression of mir-21 in the high-MYCN neuroblastoma cells, nor repression of increased mir-21 levels during MYCN knockdown-mediated differentiation had any significant effects on cell differentiation or proliferation. CONCLUSIONS: We describe a subset of miRNAs that were altered during the N-myc deprived differentiation of MYCN-amplified neuroblastoma cells. In this context, N-myc acts as both an activator and suppressor of miRNA expression. Mir-21 was up-regulated during cell differentiation, but inhibition of mir-21 did not prevent this process. We were unable to establish a role for this miRNA during differentiation and proliferation of the two neuroblastoma cell lines used in this study.

[Reliability of air ambulances--a survey in three municipalities in Helgeland?]. / Luftambulansens pålitelighet - en undersøkelse i tre kommuner på Helgeland.

BACKGROUND: The Norwegian health authorities have promised the population equal health service, also in the most remote areas; the air ambulance system is important in reaching this goal. It is likely that changes in hospitals' systems for emergency preparedness will increasingly require air ambulance transport. We wanted to find out how reliable the air ambulance is in a remote area with difficult accessibility. MATERIAL AND METHODS: Data have been retrieved from the air ambulance's database and quality-assured against the database for the acute medical services in a three-month period (1 November 2006 - to 31 October 2007). RESULTS: 105 calls were recorded from the area assessed. Reliability of the services was best in June and July, when all requests were served. The helicopter was only available for 7 of 24 requests from November to February. During the entire year, 79 requests were considered medically necessary and of these the helicopter was only available for 42. INTERPRETATION: Our survey indicates that a considerable part of the population has poor air ambulance regularity during the winter. This must be taken into consideration when planning emergency health service.

Pacemaker implantation in patients with persistent left superior vena cava.

Implantation of a permanent pacemaker system is most commonly performed by puncturing the left subclavian vein and introducing the pacemaker lead(s) through the superior caval vein to the right atrium and/or ventricle. Occasionally, a persistent left superior caval vein is encountered peroperatively, complicating the procedure. This article describes three such patients and provides a review of the literature regarding one of the most common anomalies of the thoracic vessels.