ALBERT

Description: We present results from multiwavelength observations of the BL Lacertae object 1ES 1741 + 196, including results in the very high energy -ray regime using the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The VERITAS time-averaged spectrum, measured above 180 GeV, is well modelled by a power law with a spectral index of 2.7 ± 0.7 stat ± 0.2 syst . The integral flux above 180 GeV is (3.9 ± 0.8 stat ± 1.0 syst ) x 10 –8 m –2  s –1 , corresponding to 1.6 per cent of the Crab nebula flux on average. The multiwavelength spectral energy distribution of the source suggests that 1ES 1741+196 is an extreme-high-frequency-peaked BL Lacertae object. The observations analysed in this paper extend over a period of six years, during which time no strong flares were observed in any band. This analysis is therefore one of the few characterizations of a blazar in a non-flaring state.

Description: Muscles are composed of multinucleated muscle fibers with different contractile and physiological properties, which result from specific slow or fast gene expression programs in the differentiated muscle cells. In the zebra fish embryo, the slow program is under the control of Hedgehog signaling from the notochord and floor plate. This pathway activates the expression of the conserved transcriptional repressor, Prdm1 (Blimp1), which in turn represses the fast program and promotes the slow program in adaxial cells of the somite and their descendants. In the mouse embryo, myogenesis is also initiated in the myotomal compartment of the somite, but the slow muscle program is not confined to a specific subset of cells. We now show that Prdm1 is expressed in the first differentiated myocytes of the early myotome from embryonic day (E)9.5–E11.5. During this period, muscle formation depends on the myogenic regulatory factors, Myf5 and Mrf4. In their absence, Prdm1 is not activated, in apparent contrast to zebra fish where Prdm1 is expressed in the absence of Myf5 and MyoD that drive myogenesis in adaxial cells. However, as in zebra fish, Prdm1 expression in the mouse myotome does not occur in the absence of Hedgehog signaling. Analysis of the muscle phenotype of Prdm1 mutant embryos shows that myogenesis appears to proceed normally. Notably, there is no requirement for Prdm1 activation of the slow muscle program in the mouse myotome. Furthermore, the gene for the transcriptional repressor, Sox6, which is repressed by Prdm1 to permit slow muscle differentiation in zebra fish, is not expressed in the mouse myotome. We propose that the lack of functional conservation for mouse Prdm1, that can nevertheless partially rescue the adaxial cells of zebra fish Prdm1 mutants, reflects differences in the evolution of the role of key regulators such as Prdm1 or Sox6, in initiating the onset of the slow muscle program, between teleosts and mammals.

Description: Congenital heart defects affect at least 0.8% of newborn children and are a major cause of lethality prior to birth. Malformations of the arterial pole are particularly frequent. The myocardium at the base of the pulmonary trunk and aorta and the arterial tree associated with these great arteries are derived from splanchnic mesoderm of the second heart field (SHF), an important source of cardiac progenitor cells. These cells are controlled by a gene regulatory network that includes Fgf8 , Fgf10 and Tbx1. Prdm1 encodes a transcriptional repressor that we show is also expressed in the SHF. In mouse embryos, mutation of Prdm1 affects branchial arch development and leads to persistent truncus arteriosus (PTA), indicative of neural crest dysfunction. Using conditional mutants, we show that this is not due to a direct function of Prdm1 in neural crest cells. Mutation of Prdm1 in the SHF does not result in PTA, but leads to arterial pole defects, characterized by mis-alignment or reduction of the aorta and pulmonary trunk, and abnormalities in the arterial tree, defects that are preceded by a reduction in outflow tract size and loss of caudal pharyngeal arch arteries. These defects are associated with a reduction in proliferation of progenitor cells in the SHF. We have investigated genetic interactions with Fgf8 and Tbx1 , and show that on a Tbx1 heterozygote background, conditional Prdm1 mutants have more pronounced arterial pole defects, now including PTA. Our results identify PRDM1 as a potential modifier of phenotypic severity in TBX1 haploinsufficient DiGeorge syndrome patients.

Description: Bacteria of the genus Xenorhabdus are symbionts of soil entomopathogenic nematodes of the genus Steinernema . This symbiotic association constitutes an insecticidal complex active against a wide range of insect pests. Unlike other Xenorhabdus species, Xenorhabdus poinarii is avirulent when injected into insects in the absence of its nematode host. We sequenced the genome of the X. poinarii strain G6 and the closely related but virulent X. doucetiae strain FRM16. G6 had a smaller genome (500–700 kb smaller) than virulent Xenorhabdus strains and lacked genes encoding potential virulence factors (hemolysins, type 5 secretion systems, enzymes involved in the synthesis of secondary metabolites, and toxin–antitoxin systems). The genomes of all the X. poinarii strains analyzed here had a similar small size. We did not observe the accumulation of pseudogenes, insertion sequences or decrease in coding density usually seen as a sign of genomic erosion driven by genetic drift in host-adapted bacteria. Instead, genome reduction of X. poinarii seems to have been mediated by the excision of genomic blocks from the flexible genome, as reported for the genomes of attenuated free pathogenic bacteria and some facultative mutualistic bacteria growing exclusively within hosts. This evolutionary pathway probably reflects the adaptation of X. poinarii to specific host.

Description: Bacteria of the genus Xenorhabdus are symbionts of soil entomopathogenic nematodes of the genus Steinernema . This symbiotic association constitutes an insecticidal complex active against a wide range of insect pests. Within Xenorhabdus bovienii species, the X. bovienii CS03 strain ( Xb CS03) is nonvirulent when directly injected into lepidopteran insects, and displays a low virulence when associated with its Steinernema symbiont. The genome of Xb CS03 was sequenced and compared with the genome of a virulent strain, X. bovienii SS-2004 ( Xb SS-2004). The genome size and content widely differed between the two strains. Indeed, Xb CS03 had a large genome containing several specific loci involved in the inhibition of competitors, including a few NRPS-PKS loci (nonribosomal peptide synthetases and polyketide synthases) producing antimicrobial molecules. Consistently, Xb CS03 had a greater antimicrobial activity than Xb SS-2004. The Xb CS03 strain contained more pseudogenes than Xb SS-2004. Decay of genes involved in the host invasion and exploitation (toxins, invasins, or extracellular enzymes) was particularly important in Xb CS03. This may provide an explanation for the nonvirulence of the strain when injected into an insect host. We suggest that Xb CS03 and Xb SS-2004 followed divergent evolutionary scenarios to cope with their peculiar life cycle. The fitness strategy of Xb CS03 would involve competitor inhibition, whereas Xb SS-2004 would quickly and efficiently kill the insect host. Hence, Xenorhabdus strains would have widely divergent host exploitation strategies, which impact their genome structure.

Description: Best practices and international standards for determining n-year return period extreme wave (sea states) conditions allow wave energy converter designers and project developers the option to apply simple univariate or more complex bivariate extreme value analysis methods. The present study compares extreme sea state estimates derived from univariate and bivariate methods and investigates the performance of spectral wave models for predicting extreme sea states at buoy locations within several regional wave climates along the US East and West Coasts. Two common third-generation spectral wave models are evaluated, a WAVEWATCH III® model with a grid resolution of 4 arc-minutes (6–7 km), and a Simulating WAves Nearshore model, with a coastal resolution of 200–300 m. Both models are used to generate multi-year hindcasts, from which extreme sea state statistics used for wave conditions characterization can be derived and compared to those based on in-situ observations at National Data Buoy Center stations. Comparison of results using different univariate and bivariate methods from the same data source indicates reasonable agreement on average. Discrepancies are predominantly random. Large discrepancies are common and increase with return period. There is a systematic underbias for extreme significant wave heights derived from model hindcasts compared to those derived from buoy measurements. This underbias is dependent on model spatial resolution. However, simple linear corrections can effectively compensate for this bias. A similar approach is not possible for correcting model-derived environmental contours, but other methods, e.g., machine learning, should be explored.

Description: Opportunities and constraints for wave energy conversion technologies and projects are evaluated by identifying and characterizing the dominant wave energy systems for United States (US) coastal waters using marginal and joint distributions of the wave energy in terms of the peak period, wave direction, and month. These distributions are computed using partitioned wave parameters generated from a 30 year WaveWatch III model hindcast, and regionally averaged to identify the dominant wave systems contributing to the total annual available energy ( A A E ) for eleven distinct US wave energy climate regions. These dominant wave systems are linked to the wind systems driving their generation and propagation. In addition, conditional resource parameters characterizing peak period spread, directional spread, and seasonal variability, which consider dependencies of the peak period, direction, and month, are introduced to augment characterization methods recommended by international standards. These conditional resource parameters reveal information that supports project planning, conceptual design, and operation and maintenance. The present study shows that wave energy resources for the United States are dominated by long-period North Pacific swells (Alaska, West Coast, Hawaii), short-period trade winds and nor’easter swells (East Coast, Puerto Rico), and wind seas (Gulf of Mexico). Seasonality, peak period spread, and directional spread of these dominant wave systems are characterized to assess regional opportunities and constraints for wave energy conversion technologies targeting the dominant wave systems.

Description: We have taken a genetic strategy to define the mechanisms underlying the increased risk of VTE in myeloma patient treated with thalidomide using clinical trial data derived from the MRC, ECOG, Little Rock and HOVON trial groups. Baseline VTE rates in the MRC IX study, (CTD vs CVAD; n=748 no prophylactic anticoagulation), were 14%. Rates in both arms were equal but in the thalidomide arm, thrombotic events were all DVT’s or PE’s, whereas in the CVAD arm they split equally between line related and VTE’s. In the other comparison (CTD vs MP; n=542), the VTE rate was 17%, all in the thalidomide arm. Rates were similar or higher (30%) in the other trials depending on the intensity of treatment used. We carried out a nested case control on DNA from MRC IX on 90 VTE (45 thalidomide, 45 non-thalidomide related), matched to 180 controls. SNPlex analysis for 60 SNPs in the coagulation cascade, DNA repair, thalidomide, metabolism and myeloma specific pathways, identified 7 genes which affected risk (NBS1, MTHFR, Ku80, Cyp3A5, LGAL52 and IL12B). This suggests three major pathways contribute to the risk of thalidomide related VTE, metabolism of thalidomide, tumour responsiveness and some pro-thrombotic factors. These factors differ from non-thalidomide related risk where a strong pro-inflammatory response is most relevant. We tested this hypothesis further using an expanded panel of 3,404 SNPs (BOAC panel), using the Megalle system. Statistical analysis of this data defined the top 20 thalidomide and non-thalidomide associated SNPs, which were consistent with the initial hypothesis, the results of which exclude variation in the coagulation cascade as being a significant risk factor. We explored this hypothesis further using pathway-based analysis focussing on the MTHFR, DNA repair and WNT pathways on data from the ECOG, HOVON and Little Rock data sets. The biological relevance of the SNPs and genes identified was validated by correlating the level of expression using the Affymetrix U133 CHIP with genetic variation at the DNA level. To verify the relevance of DNA repair variability to tumour response further, we correlated gene expression profiling with response and again Ku80 was identified as one of a cluster of genes defining increased risk. The data suggests that the risk of thalidomide related VTE relates to rapid tumour lysis combined with a prothrombotic tendency, whereas in line related thrombosis, risk is dependent upon a strong proinflammatory response. We are building this genetic data into a clinical risk model in order to allow us to develop a rationale for intervention strategies.

Description: Background: Cytotoxic T-cell infiltrates are a nearly universal finding in the bone marrow of patients with multiple myeloma. It has been postulated that presence of T-cells in the bone marrow of multiple myeloma (MM) patients represents an immune response against the tumor and therefore, might be associated with an improved prognosis. However, the impact of bone marrow T-cells on the prognosis of multiple myeloma patients has not been studied systematically. Methods: Bone marrow biopsies of patients with newly diagnosed multiple myeloma were stained by immnohistochemistry for the CD8 antigen and reviewed by a blinded hematopathologist. Three high power fields are reviewed for each biopsy and the total number of CD8 positive cells counted and reported. For patients with more than 300 cells per 3 fields, results were reported as 〉300. The number of bone marrow CD8 positive cells was then correlated with patients’ clinical data, including other prognostic factors and overall survival. Results: Bone marrow biopsy specimens from 100 patients, performed within the week of a diagnosis of multiple myeloma and collected between May 1998 and January 2001 were evaluated. The median number of CD8 positive cells was 270 (33 – 〉300). Patients’ characteristics are shown in Table 1. Median follow up was 30 months (0–80). The number of cytotoxic T-cells as a continuous variable was a risk factor for shortened overall survival, HR 1.86 (95% CI 1.11–3.35). Using minimal p value approach, the cutoff of 270 cells (the median) risk stratified patients into two groups: the median survival of patients with 〉 270 CD8 positive cells was 16 months vs. 48 months in patients with ≤270 cells, p=0.005 (Figure). In multivariate analysis including age, B2M, albumin, CRP, bone marrow plasma cell percentage and plasma cell labeling index, the number of cytotoxic T-cells was an independent predictor of overall survival was HR 3.1, p=0.0017. Conclusion: We show that the number of cytotoxic T-cells in the bone marrow is a strong and independent prognostic factor in patients with newly diagnosed multiple myeloma. Our observation does not contradict the hypothesis that cytotoxic T-cells participate in an immune response against the tumor since our findings may represent a higher level of immune response associated with baseline aggressive disease biology. However, our study suggests for the first time that increased marrow cytotoxic T-cells have an adverse effect on outcome in myeloma, and suggest that these cells may have a direct facilitating effect on tumor growth and on the marrow microenvironment. Further studies of the biology of behind this observation are warranted. Characteristic N Median (range) Gender male 61 CRP 81 0.4mg/L (0.01–11.2) Albumin 99 3.6 g/dL (2.6–5.4) B2microglobulin 94 4.0 (0.9–28) μg/mL Marrow PC% 90 45% (11–99) PC labeling index 90 high (〉1%) 36 BM CD8 cells 100 270 (33 – 〉300) ISS 94 1 19 2 41 3 34 Figure Figure

Description: Background: In patients (pts) with newly diagnosed myeloma (MM) eligible for high dose therapy and autologous stem cell transplantation (ASCT), the standard approach is 4–6 months of induction therapy followed by ASCT. The combination of thalidomide and dexamethasone is one of the commonly used induction regimens, and has superior response rates compared to dexamethasone or VAD. Almost all patients undergoing an ASCT relapse at a median interval of 18–24 months. The choice of treatments at first relapse is variable, but re-application of the original induction regimen, if effective is often considered. It is not clear if the responses obtained at the time of induction therapy can be replicated at the time of relapse. We studied the response of thalidomide based regimens when used as first treatment after relapse from an ASCT in patients receiving thalidomide as induction treatment. Methods: Pts who received thalidomide and dexamethasone as induction therapy, and thalidomide ± dexamethasone at first relapse after ASCT were identified for the current study. A group of patients receiving dexamethasone as induction therapy and thalidomide ± dexamethasone at first relapse after ASCT was used as the control group. Results: There were 20 pts in the study group (group 1) and 14 patients in the control group (group 2) identified between 2002 and 2007. There were 15 (75%) males in group 1 and 10 (71%) in group 2. In group 1 there was 1(5%) complete response (CR), 5 (25%) very good partial response (VGPR) and 14 (70%) partial responses (PR) to induction therapy. In group 2 there was 1 (7%)VGPR, 12 (86%) PR and 1 (7%)stable disease following dexamethasone induction. Upon treatment with thalidomide based regimens at first relapse after ASCT, there was a high rate of treatment failures in group 1 as compared to group 2 (no response in 14 out of 20 patients (70%) versus 5 of 14 pts (35%), respectively, p = 0.04). Of the 10 patients with progressive disease in group 1 post transplant, 30% had previously achieved a VGPR and 70% had previously achieved a PR to thalidomide/dexamethasone pre-ASCT. Conclusions: Our study provides evidence toward the lack of efficacy of thalidomide based regimens on post ASCT relapse in patients who had thalidomide responsive disease prior to ASCT. It is possible that this applies to other induction regimens when used at post ASCT relapse and raises the possibility of selection of drug resistant clones with initial therapy. Response rates seen with drug regimens prior to ASCT may not be reproducible at the time of relapse after ASCT.