Scalable 30 fs laser source with 530 W average power.

We present a power-scalable laser source with 30 fs pulse duration, 530 W average power at 500 kHz repetition rate, and beam quality M2<1.2. The compact and efficient setup consists of ytterbium-based Innoslab amplifiers and subsequent nonlinear pulse compression with an argon-filled Herriott cell.

Triggered activity in atrial myocytes is influenced by Na+/Ca2+ exchanger activity in genetically altered mice.

AIMS: In atrial fibrillation, increased function of the Na+/Ca2+-exchanger (NCX) is one among several electrical remodeling mechanisms. METHODS/RESULTS: Using the patch-clamp- and Ca2+ imaging-methods, we investigated atrial myocytes from NCX-homozygous-overexpressor (OE)- and heterozygous-knockout (KO)-mice and their corresponding wildtypes (WTOE; WTKO). NCX mediated Ca2+ extrusion capacity was reduced in KO and increased in OE. There was no evidence for structural or molecular remodeling. During a proarrhythmic pacing-protocol, the number of low amplitude delayed afterdepolarizations (DADs) was unaltered in OE vs. WTOE and KO vs. WTKO. However, DADs triggered full spontaneous action potentials (sAP) significantly more often in OE vs. WTOE (ratio sAP/DAD: OE:0.18±0.05; WTOE:0.02±0.02; p<0.001). Using the same protocol, a DAD triggered an sAP by tendency less often in KO vs. WTKO (p=0.06) and significantly less often under a more aggressive proarrhythmic protocol (ratio sAP/DAD: KO:0.01±0.003; WT KO: 0.12±0.05; p=0.007). The DAD amplitude was increased in OE vs. WTOE and decreased in KO vs. WTKO. There were no differences in SR-Ca2+-load, the number of spontaneous Ca2+-release-events or IKACh/IK1. CONCLUSIONS: Atrial myocytes with increased NCX expression exhibited increased vulnerability towards sAPs while atriomyocytes with reduced NCX expression were protected. The underlying mechanism consists of a modification of the DAD-amplitude by the level of NCX-activity. Thus, although the number of spontaneous Ca2+-releases and therefore DADs is unaltered, the higher DAD-amplitude in OE made a transgression of the voltage-threshold of an sAP more likely. These findings indicate that the level of NCX activity could influence triggered activity in atrial myocytes independent of possible remodeling processes.

Cardiac expression of the CREM repressor isoform CREM-IbΔC-X in mice leads to arrhythmogenic alterations in ventricular cardiomyocytes.

Chronic ß-adrenergic stimulation is regarded as a pivotal step in the progression of heart failure which is associated with a high risk for arrhythmia. The cAMP-dependent transcription factors cAMP-responsive element binding protein (CREB) and cAMP-responsive element modulator (CREM) mediate transcriptional regulation in response to ß-adrenergic stimulation and CREM repressor isoforms are induced after stimulation of the ß-adrenoceptor. Here, we investigate whether CREM repressors contribute to the arrhythmogenic remodeling in the heart by analyzing arrhythmogenic alterations in ventricular cardiomyocytes (VCMs) from mice with transgenic expression of the CREM repressor isoform CREM-IbΔC-X (TG). Patch clamp analyses, calcium imaging, immunoblotting and real-time quantitative RT-PCR were conducted to study proarrhythmic alterations in TG VCMs vs. wild-type controls. The percentage of VCMs displaying spontaneous supra-threshold transient-like Ca(2+) releases was increased in TG accompanied by an enhanced transduction rate of sub-threshold Ca(2+) waves into these supra-threshold events. As a likely cause we discovered enhanced NCX-mediated Ca(2+) transport and NCX1 protein level in TG. An increase in I NCX and decrease in I to and its accessory channel subunit KChIP2 was associated with action potential prolongation and an increased proportion of TG VCMs showing early afterdepolarizations. Finally, ventricular extrasystoles were augmented in TG mice underlining the in vivo relevance of our findings. Transgenic expression of CREM-IbΔC-X in mouse VCMs leads to distinct arrhythmogenic alterations. Since CREM repressors are inducible by chronic ß-adrenergic stimulation our results suggest that the inhibition of CRE-dependent transcription contributes to the formation of an arrhythmogenic substrate in chronic heart disease.

Targeted Therapy for Neuroblastoma: ALK Inhibitors.

Treatment for neuroblastoma, the most common extracranial childhood tumor, spans a broad range of aggressiveness that mirrors the risk profiles of disease subtypes, with high-risk neuroblastoma still presenting a clinical challenge. Currently, most patients with relapsed neuro-blastoma die of disease and present a major challenge for treatment. New therapeutic options are urgently needed to improve patient survival. Activating mutations in the gene encoding the anaplastic lymphoma kinase (ALK) remain the most frequent druggable mutations identified in neuroblastomas to date. Preclinical data support an oncogene addiction of neuroblastoma cells to mutated ALK and demonstrate that ALK inhibitory therapy strongly combats tumor models. Most recently, pediatric phase I testing has been completed for the first approved ALK inhibitor, Crizotinib, showing very encouraging antitumoral results in neuroblastoma patients. Subsequently, an international phase I study with the second generation ALK inhibitor, LDK-378, will be launched that makes ALK inhibitory therapy also available to pediatric patients in Germany.

Exon-level expression analyses identify MYCN and NTRK1 as major determinants of alternative exon usage and robustly predict primary neuroblastoma outcome.

BACKGROUND: Using mRNA expression-derived signatures as predictors of individual patient outcome has been a goal ever since the introduction of microarrays. Here, we addressed whether analyses of tumour mRNA at the exon level can improve on the predictive power and classification accuracy of gene-based expression profiles using neuroblastoma as a model. METHODS: In a patient cohort comprising 113 primary neuroblastoma specimens expression profiling using exon-level analyses was performed to define predictive signatures using various machine-learning techniques. Alternative transcript use was calculated from relative exon expression. Validation of alternative transcripts was achieved using qPCR- and cell-based approaches. RESULTS: Both predictors derived from the gene or the exon levels resulted in prediction accuracies >80% for both event-free and overall survival and proved as independent prognostic markers in multivariate analyses. Alternative transcript use was most prominently linked to the amplification status of the MYCN oncogene, expression of the TrkA/NTRK1 neurotrophin receptor and survival. CONCLUSION: As exon level-based prediction yields comparable, but not significantly better, prediction accuracy than gene expression-based predictors, gene-based assays seem to be sufficiently precise for predicting outcome of neuroblastoma patients. However, exon-level analyses provide added knowledge by identifying alternative transcript use, which should deepen the understanding of neuroblastoma biology.

CREB critically regulates action potential shape and duration in the adult mouse ventricle.

The cAMP response element binding protein (CREB) belongs to the CREB/cAMP response element binding modulator/activating transcription factor 1 family of cAMP-dependent transcription factors mediating a regulation of gene transcription in response to cAMP. Chronic stimulation of ß-adrenergic receptors and the cAMP-dependent signal transduction pathway by elevated plasma catecholamines play a central role in the pathogenesis of heart failure. Ion channel remodeling, particularly a decreased transient outward current (I(to)), and subsequent action potential (AP) prolongation are hallmarks of the failing heart. Here, we studied the role of CREB for ion channel regulation in mice with a cardiomyocyte-specific knockout of CREB (CREB KO). APs of CREB KO cardiomyocytes were prolonged with increased AP duration at 50 and 70% repolarization and accompanied by a by 51% reduction of I(to) peak amplitude as detected in voltage-clamp measurements. We observed a 29% reduction of Kcnd2/Kv4.2 mRNA in CREB KO cardiomyocytes mice while the other I(to)-related channel subunits Kv4.3 and KChIP2 were not different between groups. Accordingly, Kv4.2 protein was reduced by 37% in CREB KO. However, we were not able to detect a direct regulation of Kv4.2 by CREB. The I(to)-dependent AP prolongation went along with an increase of I(Na) and a decrease of I(Ca,L) associated with an upregulation of Scn8a/Nav1.6 and downregulation of Cacna1c/Cav1.2 mRNA in CREB KO cardiomyocytes. Our results from mice with cardiomyocyte-specific inactivation of CREB definitively indicate that CREB critically regulates the AP shape and duration in the mouse ventricle, which might have an impact on ion channel remodeling in situations of altered cAMP-dependent signaling like heart failure.

Biological Impact on the Stability and Reliability of Acute and Chronic Platinum based Thin Film Neural Interfaces in Vivo.

Reliability, stability and biocompatibility of an im-plant are the keys to transferring a preclinical study into the re-ality of clinical applications for diagnostics and therapy of pa-tients. Amongst the smallest and most critical components of neuroprostheses are the neural interfaces to the tissue. These could be seen as the most functional and yet most sensitive parts to connect to and interact with the nervous system. Thin film systems in the submicro- to nanometers range with a high num-ber of channels record biological signals and excite nerves aspiring high spatial sensitivity at the scale of few neurons. The im-pairments of the technical material caused by the harsh environ-ment of the human body and potential damage to the tissue by the foreign body state the greatest obstacle to overcome. Here, we present an analysis on impact of acutely and chronically im-planted subdural electrocorticography (ECoG) recording arrays on the neural tissue and the accompanied material failure mechanisms of the thin film neural interfaces in vivo.

Evolutionary origins and diversification of dragon lizards in Australia's tropical savannas.

Australia's monsoonal tropics are dominated by the largest and least modified savanna woodlands in the world, and they are globally significant for their high biodiversity and regional endemism. Despite this, there have been very few molecular studies of the evolutionary origins and diversification of vertebrates in this region. The semi-arboreal dragon lizards of Lophognathus and Amphibolurus are widely distributed in the savanna and dry sclerophyll woodlands of Australasia, including the monsoon tropics. We sequenced a ~1400 bp region of mitochondrial DNA and a ~1400 bp nuclear gene (RAG1) to investigate the phylogenetic relationships and phylogeographic structuring of all seven species of Lophognathus and Amphibolurus. Our analyses show that there is a higher level of species and generic diversity in the monsoon tropics than previously thought, and a full morphological review and taxonomic revision of these genera is required. Relaxed molecular clock analyses indicate that species across both genera originated in the late Miocene and early Pliocene, with significant phylogeographic structure within species. We did not find any evidence that the monsoon tropics species were a monophyletic group that had diversified within the region; instead Amphibolurus and Lophognathus represent at least three independent evolutionary colonizations of the monsoon tropics. It is probable that the origins and phylogeographic patterns of the northern Lophognathus species have evolved under the climatic influence of the Australian monsoon, rather than being either an ancient Gondwanan lineage that pre-dates the monsoon or the result of a more recent dispersal event across Wallace's Line.

Habitat use affects morphological diversification in dragon lizards.

Habitat use may lead to variation in diversity among evolutionary lineages because habitats differ in the variety of ways they allow for species to make a living. Here, we show that structural habitats contribute to differential diversification of limb and body form in dragon lizards (Agamidae). Based on phylogenetic analysis and ancestral state reconstructions for 90 species, we find that multiple lineages have independently adopted each of four habitat use types: rock-dwelling, terrestriality, semi-arboreality and arboreality. Given these reconstructions, we fit models of evolution to species' morphological trait values and find that rock-dwelling and arboreality limit diversification relative to terrestriality and semi-arboreality. Models preferred by Akaike information criterion infer slower rates of size and shape evolution in lineages inferred to occupy rocks and trees, and model-averaged rate estimates are slowest for these habitat types. These results suggest that ground-dwelling facilitates ecomorphological differentiation and that use of trees or rocks impedes diversification.

Antiretroviral therapy and preterm delivery-a pooled analysis of data from the United States and Europe.

OBJECTIVE: To investigate reported differences in the association between highly active antiretroviral therapy (HAART) in pregnancy and the risk of preterm delivery among HIV-infected women. DESIGN: Combined analysis of data from three observational studies. SETTING: USA and Europe. POPULATION: A total of 19, 585 singleton infants born to HIV-infected women, 1990-2006. METHODS: Data from the Pediatric Spectrum of HIV Disease project (PSD), a US monitoring study, the European Collaborative Study (ECS), a consented cohort study, and the National Study of HIV in Pregnancy and Childhood (NSHPC), the United Kingdom and Ireland surveillance study. MAIN OUTCOME MEASURE: Preterm delivery rate (<37 weeks of gestation). RESULTS: Compared with monotherapy, HAART was associated with increased preterm delivery risk in the ECS (adjusted odds ratio [AOR] 2.40, 95% CI 1.49-3.86) and NSHPC (AOR 1.43, 95% CI 1.10-1.86), but not in the PSD (AOR 0.92, 95% CI 0.67-1.26), after adjusting for relevant covariates. Because of heterogeneity, data were not pooled for this comparison, but heterogeneity disappeared when HAART was compared with dual therapy (P = 0.26). In a pooled analysis, HAART was associated with 1.5-fold increased odds of preterm delivery compared with dual therapy (95% CI 1.19-1.87, P=0.001), after adjusting for covariates. CONCLUSIONS: Heterogeneity in the association between HAART and preterm delivery was not explained by study design, adjustment for confounders or a standard analytical approach, but may have been the result of substantial differences in populations and data collected. The pooled analysis comparing HAART with dual therapy showed an increased risk of preterm delivery associated with HAART.

Insulin-like growth factor-1 receptor acts as a growth regulator in synovial sarcoma.

Synovial sarcomas account for 5-10% of all soft tissue sarcomas and the majority of synovial sarcomas display characteristic t(X;18) translocations that result in enhanced transcription of the insulin-like growth factor-2 (IGF-2) gene. IGF-2 is an essential fetal mitogen involved in the pathogenesis of different tumours, leading to cellular proliferation and inhibition of apoptosis. Here we asked whether activation of IGF signalling is of functional importance in synovial sarcomas. We screened human synovial sarcomas for expression of IGF-2 and the phosphorylated IGF-1 receptor (IGF-1R), which mainly mediates the proliferative and anti-apoptotic effects of IGF-2. Since both the phosphatidylinositol 3'-kinase (PI3K)-AKT pathway and the MAPK signalling cascade are known to be involved in the transmission of IGF-1R signals, expression of phosphorylated (p)-AKT and p-p44/42 MAPK was additionally assessed. All tumours expressed IGF-2 and 78% showed an activated IGF-1R. All tumours were found to express p-AKT and 92% showed expression of activated p44/42 MAPK. To analyse the functional and potential therapeutic relevance of IGF-1R signalling, synovial sarcoma cell lines were treated with the IGF-1R inhibitor NVP-AEW541. Growth was impaired by the IGF-1R antagonist, which was consistently accompanied by a dose-dependent reduction of phosphorylation of AKT and p44/42 MAPK. Functionally, inhibition of the receptor led to increased apoptosis and diminished mitotic activity. Concurrent exposure of selected cells to NVP-AEW541 and conventional chemotherapeutic agents resulted in positive interactions. Finally, synovial sarcoma cell migration was found to be dependent on signals transmitted by the IGF-1R. In summary, our data show that the IGF-1R might represent a promising therapeutic target in synovial sarcomas.

High-flux ultrafast extreme-ultraviolet photoemission spectroscopy at 18.4 MHz pulse repetition rate.

Laser-dressed photoelectron spectroscopy, employing extreme-ultraviolet attosecond pulses obtained by femtosecond-laser-driven high-order harmonic generation, grants access to atomic-scale electron dynamics. Limited by space charge effects determining the admissible number of photoelectrons ejected during each laser pulse, multidimensional (i.e. spatially or angle-resolved) attosecond photoelectron spectroscopy of solids and nanostructures requires high-photon-energy, broadband high harmonic sources operating at high repetition rates. Here, we present a high-conversion-efficiency, 18.4-MHz-repetition-rate cavity-enhanced high harmonic source emitting 5 × 105 photons per pulse in the 25-to-60-eV range, releasing 1 × 1010 photoelectrons per second from a 10-µm-diameter spot on tungsten, at space charge distortions of only a few tens of meV. Broadband, time-of-flight photoelectron detection with nearly 100% temporal duty cycle evidences a count rate improvement between two and three orders of magnitude over state-of-the-art attosecond photoelectron spectroscopy experiments under identical space charge conditions. The measurement time reduction and the photon energy scalability render this technology viable for next-generation, high-repetition-rate, multidimensional attosecond metrology.

A new role for extracellular Ca2+ in gap-junction remodeling: studies in humans and rats.

We wanted to elucidate whether extracellular calcium may regulate the expression of the cardiac gap-junction proteins connexin 40 and connexin43. In the free wall of the left atria of 126 cardiac surgery patients with either sinus rhythm (SR) or chronic atrial fibrillation (AF), we determined the expression of the cardiac gap-junction proteins Cx43 and Cx40 by Western blot and immunohistology. For deeper investigation, we incubated cultured neonatal rat cardiomyocytes at 2 or 4 mM Ca(++) for 24 h and determined intercellular coupling, Cx40, Cx43 protein and mRNA expression, protein trafficking and sensitivity to verapamil (10-100 nM), cyclosporin A (1 microM),and BMS605401 (100 nM), a specific inhibitor of Ca(2+)-sensing receptor (CaSR). We found in patients that both Cx are up-regulated in AF in the left atrium (by 100-200%). Interestingly, Cx40 was mainly up-regulated, if total serum calcium was >or=2.2 mM, while Cx43 was independent from extracellular [Ca(++)]. In cultured cells, 4 mM Ca(++)-exposure lead to up-regulation of Cx40, but not Cx43. We found enhanced Cx40 in the plasma membrane and reduced Cx40 in the Golgi apparatus. The membrane Cx40 up-regulation resulted in enhanced gap-junction intercellular coupling with a shift in the Boltzmann fit of voltage-dependent inactivation indicating a higher contribution of Cx40 as revealed by dual whole cell voltage clamp experiments. BMS605401 could prevent all Ca(2+)-induced changes. Moreover, cyclosporin A completely abolished the Ca(2+)-induced changes, while verapamil was ineffective. We conclude that extracellular calcium (24 h exposure) seems to up-regulate Cx40 but not Cx43.

CREM-transgene mice: An animal model of atrial fibrillation and thrombogenesis.

BACKGROUND: The molecular pathomechanisms underlying atrial thrombogenesis are multifactorial and still require detailed investigations. Transgenic mice with cardiomyocyte-directed expression of the transcriptional repressor CREM-IbΔC-X (CREM-TG) represent an experimental model of atrial fibrillation (AF) that shows a gradual, age-dependent progression from atrial ectopy to persistent AF. Importantly, this model develops biatrial thrombi. The molecular characteristics related to the thrombogenesis in CREM-TG mice have not been studied, yet. METHODS: The inflammatory and prothrombotic state was evaluated at the transcriptional (qRT-PCR) and protein level in the left (LA) and right atria (RA) from CREM-TG mice at the age of 20weeks and compared to wild-type controls. Moreover, histological analyses of atrial thrombi were performed. RESULTS: The endocardial dysfunction was mirrored by diminished levels of eNOS-mRNA in both atria (RA: 0.79±0.04, LA: 0.72±0.06; each P<0.05). Moreover, the PAI-1/t-PA mRNA ratio was significantly increased in both atria (RA: 3.6±0.6; P<0.01, LA: 4.0±1.0; P<0.05) indicating a high risk of thrombus formation. However, the inflammatory phenotype was more pronounced in the RA and was reflected by a significant increase in the mRNA levels encoding adhesion molecules ICAM-1 (2.1±0.2; P<0.01), VCAM-1 (2.3±0.5; P<0.05), and selectin P (3.6±0.5: P<0.05). CONCLUSIONS: CREM-TG mice represent a valuable model for studying atrial thrombogenesis and assessing therapeutic approaches preventing embolic events in the systemic and pulmonary circulation.

Subchronic alpha- and beta-adrenergic regulation of cardiac gap junction protein expression.

Gap junction channels are essential for intercellular electrical communication in the heart. The most important cardiac gap junction proteins are connexin43 (predominantly) (Cx43), connexin40 (Cx40), and in early developmental stages connexin45. Since catecholamines play an important role in cardiac (patho)physiology, we wanted to elucidate whether catecholamines may affect expression of Cx43 and Cx40. Cultured neonatal rat cardiomyocytes were exposed for 24 h to increasing concentrations of noradrenaline (1-10000 nM) (physiological agonist at alpha and beta-adrenoceptors), resulting in significantly increased Cx43-expression, while Cx40 was unaffected. In further experiments cells were incubated with either phenylephrine (alpha-adrenergic agonist) or isoproterenol (beta-adrenergic agonist) (0.1-1000 nM) for 24 h. Both catecholamines lead to a concentration-dependent increase in Cx43 protein and mRNA expression (EC50: 10-20 nM). Inhibition experiments showed that the phenylephrine effect was transduced via PKC, while the isoproterenol effect was mediated by PKA. Dual whole-cell voltage clamp demonstrated that increased Cx43-expression was accompanied by significant increases in gap junction current. In additional in vivo experiments, adult rats were subjected to 24-h infusion of isoproterenol or phenylephrine showing again significant increase in Cx43 but not Cx40. Adrenergic stimulation of cardiomyocytes can enhance Cx43 expression thereby increasing cellular coupling, indicating a possible role for catecholamines in the regulation of cardiac gap junction expression in cardiac disease.

Two cases of intoxication with new synthetic opioid, U-47700.

BACKGROUND: Novel substances often referred to as "designer drugs" have emerged as drugs of abuse, and recognition of these is difficult as routine blood and urine screening tests do not detect these agents. U-47700 is a synthetic selective µ-opioid agonist that can be bought online for as little as $40 per gram. We report two patients presenting after insufflation of U-47700, with subsequent confirmation of this substance in urine samples. CASE DETAILS: A 26-year-old man and 24-year-old woman insufflated a substance they believed to be "synthetic cocaine." The man was found down with cyanosis and agonal respirations. He was intubated and taken to hospital where he recovered well with supportive care. The woman presented with anxiety, tremors and drowsiness and was admitted for observation. Urine samples from both patients were analyzed using GC/MS/MS and LC/QToF, and U-47700 was isolated in both cases. No other opioids were detected. DISCUSSION: These cases are concerning because U-47700 is a relatively new agent that is easy to obtain over the internet and has the potential to cause significant morbidity and mortality.

Developmental outcome of the use of etamsylate for prevention of periventricular haemorrhage in a randomised controlled trial.

OBJECTIVE: To compare neurodevelopmental outcome of survivors of the multicentre trial of etamsylate (the iRNN for ethamsylate) for prevention of periventricular haemorrhage in very low birthweight infants. DESIGN: Double blind, single observer, prospective follow up of placebo controlled study. SETTING: Six neonatal intensive care units in the United Kingdom. Neurodevelopmental outcome was assessed in health premises or children's homes. SUBJECTS: 268 of 276 survivors of the original study were seen between 3.5 and 4.2 years of age. All were inborn and weighed 1500 g or less at birth. INTERVENTION: Etamsylate 12.5 mg/kg or placebo six hourly from within one hour of delivery for four days. MAIN OUTCOME MEASURES: McCarthy scales of children's abilities, standardised neurological examination, full physical examination, functional assessment, seven letter Stycar vision test, and audiometry. RESULTS: There was no difference between the groups in neuromotor outcome (cerebral palsy) or in the general cognitive index (GCI) of the McCarthy scales (mean GCI was 93.3 for the etamsylate group (n = 133) and 89.7 for the placebo group (n = 131); p = 0.10). There were more children with GCI < 70 (9 v 19; p = 0.047) or

Large-scale analysis of 73 329 physcomitrella plants transformed with different gene disruption libraries: production parameters and mutant phenotypes.

Gene targeting in the moss Physcomitrella patens has created a new platform for plant functional genomics. We produced a mutant collection of 73 329 Physcomitrella plants and evaluated the phenotype of each transformant in comparison to wild type Physcomitrella. Production parameters and morphological changes in 16 categories, such as plant structure, colour, coverage with gametophores, cell shape, etc., were listed and all data were compiled in a database (mossDB). Our mutant collection consists of at least 1804 auxotrophic mutants which showed growth defects on minimal Knop medium but were rescued on supplemented medium. 8129 haploid and 11 068 polyploid transformants had morphological alterations. 9 % of the haploid transformants had deviations in the leaf shape, 7 % developed less gametophores or had a different leaf cell shape. Other morphological deviations in plant structure, colour, and uniformity of leaves on a moss colony were less frequently observed. Preculture conditions of the plant material and the cDNA library (representing genes from either protonema, gametophore or sporophyte tissue) used to transform Physcomitrella had an effect on the number of transformants per transformation. We found correlations between ploidy level and plant morphology and growth rate on Knop medium. In haploid transformants correlations between the percentage of plants with specific phenotypes and the cDNA library used for transformation were detected. The number of different cDNAs present during transformation had no effect on the number of transformants per transformation, but it had an effect on the overall percentage of plants with phenotypic deviations. We conclude that by linking incoming molecular, proteome, and metabolome data of the transformants in the future, the database mossDB will be a valuable biological resource for systems biology.

Development of communication networks and water quality early warning detection systems at drinking water utilities in the Ohio River Valley Basin.

Source water quality is of major concern to all drinking water utilities. The accidental introduction of contaminants to their source water is a constant threat to utilities withdrawing water from navigable or industrialized rivers. The events of 11 September, 2001 in the United States have heightened concern for drinking water utility security as their source water and finished water may be targets for terrorist acts. Efforts are underway in several parts of the United States to strengthen early warning capabilities. This paper will focus on those efforts in the Ohio River Valley Basin.

A Cre-conditional MYCN-driven neuroblastoma mouse model as an improved tool for preclinical studies.

Neuroblastoma, a childhood cancer that originates from neural crest-derived cells, is the most common deadly solid tumor of infancy. Amplification of the MYCN oncogene, which occurs in approximately 20-25% of human neuroblastomas, is the most prominent genetic marker of high-stage disease. The availability of valid preclinical in vivo models is a prerequisite to develop novel targeted therapies. We here report on the generation of transgenic mice with Cre-conditional induction of MYCN in dopamine ß-hydroxylase-expressing cells, termed LSL-MYCN;Dbh-iCre. These mice develop neuroblastic tumors with an incidence of >75%, regardless of strain background. Molecular profiling of tumors revealed upregulation of the MYCN-dependent miR-17-92 cluster as well as expression of neuroblastoma marker genes, including tyrosine hydroxylase and the neural cell adhesion molecule 1. Gene set enrichment analyses demonstrated significant correlation with MYC-associated expression patterns. Array comparative genome hybridization showed that chromosomal aberrations in LSL-MYCN;Dbh-iCre tumors were syntenic to those observed in human neuroblastomas. Treatment of a cell line established from a tumor derived from a LSL-MYCN;Dbh-iCre mouse with JQ1 or MLN8237 reduced cell viability and demonstrated oncogene addiction to MYCN. Here we report establishment of the first Cre-conditional human MYCN-driven mouse model for neuroblastoma that closely recapitulates the human disease with respect to tumor localization, histology, marker expression and genomic make up. This mouse model is a valuable tool for further functional studies and to assess the effect of targeted therapies.