JAK2V617F homozygosity arises commonly and recurrently in PV and ET, but PV is characterized by expansion of a dominant homozygous subclone

Subclones homozygous for JAK2V617F are more common in polycythemia vera (PV) than essential thrombocythemia (ET), but their prevalence and significance remain unclear. The JAK2 mutation status of 6495 BFU-E, grown in low erythropoietin conditions, was determined in 77 patients with PV or ET. Homozygous-mutant colonies were common in patients with JAK2V617F-positive PV and were surprisingly prevalent in JAK2V617F-positive ET and JAK2 exon 12-mutated PV. Using microsatellite PCR to map loss-of-heterozygosity breakpoints within individual colonies, we demonstrate that recurrent acquisition of JAK2V617F homozygosity occurs frequently in both PV and ET. PV was distinguished from ET by expansion of a dominant homozygous subclone, the selective advantage of which is likely to reflect additional genetic or epigenetic lesions. Our results suggest a model in which development of a dominant JAK2V617F-homzygous subclone drives erythrocytosis in many PV patients, with alternative mechanisms operating in those with small or undetectable homozygous-mutant clones.

Identifying PV module mismatch faults by a thermography-based temperature distribution analysis

Photovoltaic (PV) solar power generation is proven to be effective and sustainable but is currently hampered by relatively high costs and low conversion efficiency. This paper addresses both issues by presenting a low-cost and efficient temperature distribution analysis for identifying PV module mismatch faults by thermography. Mismatch faults reduce the power output and cause potential damage to PV cells. This paper first defines three fault categories in terms of fault levels, which lead to different terminal characteristics of the PV modules. The investigation of three faults is also conducted analytically and experimentally, and maintenance suggestions are also provided for different fault types. The proposed methodology is developed to combine the electrical and thermal characteristics of PV cells subjected to different fault mechanisms through simulation and experimental tests. Furthermore, the fault diagnosis method can be incorporated into the maximum power point tracking schemes to shift the operating point of the PV string. The developed technology has improved over the existing ones in locating the faulty cell by a thermal camera, providing a remedial measure, and maximizing the power output under faulty conditions.

Thermography-based virtual MPPT scheme for improving PV energy efficiency under partial shading conditions

This paper proposes a new thermography-based maximum power point tracking (MPPT) scheme to address photovoltaic (PV) partial shading faults. Solar power generation utilizes a large number of PV cells connected in series and in parallel in an array, and that are physically distributed across a large field. When a PV module is faulted or partial shading occurs, the PV system sees a nonuniform distribution of generated electrical power and thermal profile, and the generation of multiple maximum power points (MPPs). If left untreated, this reduces the overall power generation and severe faults may propagate, resulting in damage to the system. In this paper, a thermal camera is employed for fault detection and a new MPPT scheme is developed to alter the operating point to match an optimized MPP. Extensive data mining is conducted on the images from the thermal camera in order to locate global MPPs. Based on this, a virtual MPPT is set out to find the global MPP. This can reduce MPPT time and be used to calculate the MPP reference voltage. Finally, the proposed methodology is experimentally implemented and validated by tests on a 600-W PV array. 

Chp8, a diguanylate cyclase from Pseudomonas syringae pv tomato DC3000 suppresses the PAMP flagellin, increases EPS and promotes plant immune evasion.

The bacterial plant pathogen Pseudomonas syringae causes disease in a wide range of plants. The associated decrease in crop yields results in economic losses and threatens global food security. Competition exists between the plant immune system and the pathogen, the basic principles of which can be applied to animal infection pathways. P. syringae uses a type III secretion system (T3SS) to deliver virulence factors into the plant that promote survival of the bacterium. The P. syringae T3SS is a product of the hypersensitive response and pathogenicity (hrp) and hypersensitive response and conserved (hrc) gene cluster, which is strictly controlled by the codependent enhancer-binding proteins HrpR and HrpS. Through a combination of bacterial gene regulation and phenotypic studies, plant infection assays, and plant hormone quantifications, we now report that Chp8 (i) is embedded in the Hrp regulon and expressed in response to plant signals and HrpRS, (ii) is a functional diguanylate cyclase, (iii) decreases the expression of the major pathogen-associated molecular pattern (PAMP) flagellin and increases extracellular polysaccharides (EPS), and (iv) impacts the salicylic acid/jasmonic acid hormonal immune response and disease progression. We propose that Chp8 expression dampens PAMP-triggered immunity during early plant infection.

A new polycythaemia vera-associated SOCS3 SH2 mutant (SOCS3(F136L)) cannot regulate erythropoietin responses

Recently several different JAK2 exon12 mutations have been identified in V617F negative polycythaemia vera (PV) or idiopathic erythrocytosis (IE) patients. The patients present with erythrocytosis, ligand-independent cell growth and low serum erythropoietin (EPO) levels. Within this group, a deletion of amino acids 542-543 (N542-E543del) of JAK2 is most prevalent. We have previously shown that in the presence of JAK2(V617F), suppressor of cytokine signalling 3 (SOCS3) is unable to negatively regulate EPO signalling and proliferation of V617F-expressing cells. Here we report a PV patient heterozygous for the somatic JAK2(N542-E543del) mutation and a previously unreported germline mutation within the SH2 domain of SOCS3 (F136L). Interestingly, the SOCS3(F136L) mutation was detected in a Japanese myeloproliferative disorder patient cohort at double the frequency of healthy controls. Cells expressing SOCS3(F136L) had markedly elevated EPO-induced proliferation and extended EPO-induced JAK2 phosphorylation. Additionally, compared to wild-type SOCS3, mutant SOCS3 had an extended half-life in the presence of JAK2 and JAK2(N542-E543del). Our findings suggest that this loss-of-function SOCS3 mutation may have contributed to disease onset by causing deregulated JAK2 signalling in the presence of a constitutively active JAK2(N542-E543del) mutant.

Molecular and clinical features of the myeloproliferative neoplasm associated with JAK2 exon 12 mutations

Although approximately 95% of patients with polycythemia vera (PV) harbor the V617F mutation in JAK2 exon 14, several mutations in exon 12 have been described in the remaining patients. We conducted a European collaborative study to define the molecular and clinical features of patients harboring these mutations. Overall, 106 PVs were recruited and 17 different mutations identified. Irrespective of the mutation, two-thirds of patients had isolated erythrocytosis, whereas the remaining subjects had erythrocytosis plus leukocytosis and/or thrombocytosis. Compared with JAK2 (V617F)-positive PV patients, those with exon 12 mutations had significantly higher hemoglobin level and lower platelet and leukocyte counts at diagnosis but similar incidences of thrombosis, myelofibrosis, leukemia, and death. In a multivariable analysis, age more than 60 years and prior thrombosis predicted thrombosis. These findings suggest that, despite the phenotypical difference, the outcome of JAK2 exon 12 mutations-positive PV is similar to that of JAK2 (V617F)positive PV. (Blood. 2011; 117(10):2813-2816)

Philadelphia-Negative Classical Myeloproliferative Neoplasms: Critical Concepts and Management Recommendations From European LeukemiaNet

We present a review of critical concepts and produce recommendations on the management of Philadelphia-negative classical myeloproliferative neoplasms, including monitoring, response definition, first-and second-line therapy, and therapy for special issues. Key questions were selected according the criterion of clinical relevance. Statements were produced using a Delphi process, and two consensus conferences involving a panel of 21 experts appointed by the European LeukemiaNet (ELN) were convened. Patients with polycythemia vera (PV) and essential thrombocythemia (ET) should be defined as high risk if age is greater than 60 years or there is a history of previous thrombosis. Risk stratification in primary myelofibrosis (PMF) should start with the International Prognostic Scoring System (IPSS) for newly diagnosed patients and dynamic IPSS for patients being seen during their disease course, with the addition of cytogenetics evaluation and transfusion status. High-risk patients with PV should be managed with phlebotomy, low-dose aspirin, and cytoreduction, with either hydroxyurea or interferon at any age. High-risk patients with ET should be managed with cytoreduction, using hydroxyurea at any age. Monitoring response in PV and ET should use the ELN clinicohematologic criteria. Corticosteroids, androgens, erythropoiesis-stimulating agents, and immunomodulators are recommended to treat anemia of PMF, whereas hydroxyurea is the first-line treatment of PMF-associated splenomegaly. Indications for splenectomy include symptomatic portal hypertension, drug-refractory painful splenomegaly, and frequent RBC transfusions. The risk of allogeneic stem-cell transplantation-related complications is justified in transplantation-eligible patients whose median survival time is expected to be less than 5 years.

Natural history of idiopathic erythrocytosis - A retrospective case series review

Idiopathic Erythrocytosis (IE) is a diagnosis given to patients who have an absolute erythrocytosis (red cell mass more than 25% above their mean normal predicted value) but who do not have a known form of primary or secondary erythrocytosis (BCSH guideline, 2005). We report here the results of a follow-up study of 80 patients (44 male and 36 female) diagnosed with IE from the United Kingdom and the Republic of Ireland over a 10 year period. Baseline information was initially collected when investigating for molecular causes of erythrocytosis in this group. The diagnosis of IE was made on the basis of a raised red cell mass >25% above mean normal predicted value, absence of Polycythaemia Vera (PV) based on the criteria of Pearson and Messinezy (1996), and the exclusion of secondary erythrocytosis (oxygen saturation >92% on pulse oximetry, no history of sleep apnoea, no renal or hepatic pathology, and a normal oxygen dissociation curve (if indicated). The average age at diagnosis of erythrocytosis was 34.5 (2–74 years). Erythropoietin levels were available for 77/80 of the patients and were low in 18 (23%) and normal or high in 59 (74%). Ultrasound imaging was carried out in 67 patients (84%) at time of diagnosis and no significant abnormalities found. Fourteen patients had a family history of erythrocytosis. These patients have now been followed up for an average of 9.4 years (range 1–39). Out of 80 patients 56 patients can still be classified as having IE, of whom 52 are living (cause of death in the other 4 - lung cancer, RTA, sepsis, unknown). Thirty-five of these patients are regularly venesected, 3 take hydroxyurea (one also venesected), 11 receive no treatment while treatment is unknown in 2. Twenty take aspirin, 1 warfarin and 31 no thromboprophylaxis. Four of these patients had suffered thromboembolic complications (3 with CVA/TIAs and 1 with recurrent DVT) at or before their original diagnosis. Since diagnosis 8 patients have had 9 thrombotic events of which 7 were arterial (1 CVA, 3 TIAs, 1 MI, 2 PVD) and 2 venous (DVT/PE). Twenty take aspirin, 1 dipyridamole, 1 warfarin and 30 take no thromboprophylaxis. Out of the 24 patients who now have a diagnosis other than IE, 8 have been diagnosed with myelo-proliferative disease. Thirteen patients have a molecular abnormality which is likely to account for their erythrocytosis (11 VHL, 1 PHD-2, 1 EPO-receptor mutations). Three patients have secondary erythrocytosis. Older case studies identified a heterogenous group of patients, some of whom probably had apparent erythrocytosis and some who had either primary polycythaemia or secondary causes later identified (Modan and Modan, Najean et al). More recent reviews have identified a more homogenous group with low rates of transformation to myelofibrosis/acute leukaemia and low rates of thrombosis of around 1% patient-year. Follow up of our initial patient group does indeed reveal a heterogeneous group of patients with 10% now diagnosed with an MPD, although when analysis is confined to those patients who continue to fulfil the criteria for IE, the clinical course has been more stable. There has been no progression to MDS or leukaemia in this group (one patient with PV progressed to AML). The rate of thrombosis is 1.6% patient-years which is lower than the rate seen in PV and is consistent with the rate identified in other series. Molecular defects continue to be identified in this group and future investigation is likely to reveal further abnormalities.

The incidences of trisomy 8, trisomy 9 and D20S108 deletion in polycythaemia vera: an analysis of blood granulocytes using interphase fluorescence in situ hybridization:an analysis of blood granulocytes using interphase fluorescence in situ hybridization

We have used interphase fluorescence in situ hybridization (IFISH) to detect trisomy 8, trisomy 9 and 20q deletion in circulating granulocytes from patients with polycythaemia vera (PV). Out of 64 PV patients, 15 (23%) exhibited an abnormality. Two patients had trisomy 9, three had trisomy 8 and 10 patients had hemizygous deletion of D20S108 (a locus in the 20q common deleted region). Aberrant nuclei ranged from 10% to 80% in these 15 cases. There was no correlation between the presence of a marker and sex, age, interval between presentation and IFISH analysis, neutrophil or platelet count or therapy. Conventional marrow cytogenetic karyotype results were available in 23 cases and there was concurrence between these and blood IFISH in 16 cases (13 normal and three with 20q/D20S108 deletion by both methods). Three patients with D20S108 deletion by IFISH were normal by previous marrow cytogenetic testing and four cases with 20q deletion by previous marrow cytogenetics had normal blood granulocytes according to IFISH. Thus, we confirm that trisomies 8 and 9 and deletion of 20q are diagnostically useful markers of PV. IFISH analysis of blood granulocytes is a practical method for detecting these markers, but as an adjunct to, not as a substitute for, conventional marrow cytogenetics.

Erythropoietin receptor and hematological disease

This review will discuss evidence for the role of the erythropoietin (Epo) receptor in the development of erythrocytosis and other hematological disorders, The possible causative role of mutations of other genes in the pathogenesis of idiopathic erythrocytosis will be considered, Polycythemia vera (PV) is a myeloproliferative disorder that is caused by an undefined stem cell abnormality, characterized by a significant erythrocytosis, leukocytosis, and thrombocytosis. However, erythrocytosis may arise from apparent (or relative) polycythemia in which the hematocrit is raised due to a low plasma volume. In such cases the red cell mass is normal. A group of disorders with increased red cell mass caused by stimulation of erythrocyte production is known as secondary polycythemia, Investigation of such patients may reveal a congenital abnormality such as high affinity hemoglobin or an acquired abnormality caused, for example, by smoking, renal Vascular impairment, or an Epo-producing tumor. Even after thorough examination there remains a cohort of patients for whom no definite cause for the erythrocytosis can be established, A careful clinical history may reveal whether this idiopathic erythrocytosis is likely to be congenital and/or familial, in which case the term

Identification, expression, and DNA sequence of the GDP-mannose biosynthesis genes encoded by the O7 rfb gene cluster of strain VW187 (Escherichia coli O7:K1)

The O7-specific lipopolysaccharide (LPS) in strains of Escherichia coli consists of a repeating unit made of galactose, mannose, rhamnose, 4-acetamido-2,6-dideoxyglucose, and N-acetylglucosamine. We have recently cloned and characterized genetically the O7-specific LPS biosynthesis region (rfbEcO7) of the E. coli O7:K1 strain VW187 (C. L. Marolda, J. Welsh, L. Dafoe, and M. A. Valvano, J. Bacteriol. 172:3590-3599, 1990). In this study, we localized the gnd gene encoding gluconate-6-phosphate dehydrogenase at one end of the rfbEcO7 gene cluster and sequenced that end of the cluster. Three open reading frames (ORF) encoding polypeptides of 275, 464, and 453 amino acids were identified upstream of gndEcO7, all transcribed toward the gnd gene. ORF275 had 45% similarity at the protein level with ORF16.5, which occupies a similar position in the Salmonella enterica LT2 rfb region, and presumably encodes a nucleotide sugar transferase. The polypeptides encoded by ORFs 464 and 453 were expressed under the control of the ptac promoter and visualized in Coomassie blue-stained sodium dodecyl sulfate-polyacrylamide gels and by maxicell analysis. ORF464 expressed GDP-mannose pyrophosphorylase and ORF453 encoded a phosphomannomutase, the enzymes for the biosynthesis pathway of GDP-mannose, one of the nucleotide sugar precursors for the formation of the O7 repeating unit. They were designated rfbMEcO7 and rfbKEcO7, respectively. The RfbMEcO7 polypeptide was homologous to the corresponding protein in S. enterica LT2, XanB of Xanthomonas campestris, and AlgA of Pseudomonas aeruginosa, all GDP-mannose pyrophosphorylases. RfbKEcO7 was very similar to CpsG of S. enterica LT2, an enzyme presumably involved in the biosynthesis of the capsular polysaccharide colanic acid, but quite different from the corresponding RfbK protein of S. enterica LT2.

The machinist landscape:Land Art Generator Initiative (Competition)

THE MACHINIST LANDSCAPE: AN ENTROPIC GRID OF VARIANCE
‘By drawing a diagram, a ground plan of a house, a street plan to the location of a site, or a topographic map, one draws a “logical two dimensional picture”. A “logical picture” differs from a natural or realistic picture in that it rarely looks like the thing it stands for.’
A Provisional Theory of Non-Sites, Robert Smithson (1968)

Between design and ground there are variances, deviations and gaps. These exist as physical interstices between what is conceptualised and what is realised; and they reveal moments in the design process that resist the reconciliation of people and their environment (McHarg 1963). The Machinist Landscape interrogates the significance of these variances through the contrasting processes of coppice and photovoltaic energy. It builds on the potential of these gaps, and in doing so proposes that these spaces of variance can reveal the complexity of relationships between consumption and remediation, design and nature.
Fresh Kills Park, and in particular the draft master plan (2006), offers a framework to explore this artificial construct. Central to the Machinist Landscape is the analysis of the landfill gas collection system, planned on a notional 200ft grid. Variations are revealed between this diagrammatic grid measure and that which has been constructed on the site. These variances between the abstract and the real offer the Machinist Landscape a powerful space of enquiry. Are these gaps a result of unexpected conditions below ground, topographic nuances or natural phenomena? Does this space of difference, between what is planned and what is constructed, have the potential to redefine the dynamic processes and relations with the land?
The Machinist Landscape is structured through this space of variance with an ‘entropic grid’, the under-storey of which hosts a carefully managed system of short-rotation coppice (SRC). The coppice, a medieval practice related to energy, product, and space, operates on theoretical and programmatic levels. It is planted along a structure of linear bunds, stabilized through coppice pole retaining structures and enriched with nutrients from coppice produced bio-char. Above the coppice is built an upper-storey of photovoltaic (PV); its structures fabricated from the coppiced timber and the PV produced with graphene from coppice charcoal processes.