Showing papers by "David W. Johnson published in 2008"

Promoting early adolescents' achievement and peer relationships: the effects of cooperative, competitive, and individualistic goal structures.

Abstract: Emphasizing the developmental need for positive peer relationships, in this study the authors tested a social-contextual view of the mechanisms and processes by which early adolescents' achievement and peer relationships may be promoted simultaneously. Meta-analysis was used to review 148 independent studies comparing the relative effectiveness of cooperative, competitive, and individualistic goal structures in promoting early adolescents' achievement and positive peer relationships. These studies represented over 8 decades of research on over 17,000 early adolescents from 11 countries and 4 multinational samples. As predicted by social interdependence theory, results indicate that higher achievement and more positive peer relationships were associated with cooperative rather than competitive or individualistic goal structures. Also as predicted, results show that cooperative goal structures were associated with a positive relation between achievement and positive peer relationships. Implications for theory and application are discussed.

Effects of statins in patients with chronic kidney disease: meta-analysis and meta-regression of randomised controlled trials

Abstract: Objective To analyse the benefits and harms of statins in patients with chronic kidney disease (pre-dialysis, dialysis, and transplant populations). Design Meta-analysis. Data sources Cochrane Central Register of Controlled Trials, Medline, Embase, and Renal Health Library (July 2006). Study selection Randomised and quasi-randomised controlled trials of statins compared with placebo or other statins in chronic kidney disease. Data extraction and analysis Two reviewers independently assessed trials for inclusion, extracted data, and assessed trial quality. Differences were resolved by consensus. Treatment effects were summarised as relative risks or weighted mean differences with 95% confidence intervals by using a random effects model. Results Fifty trials (30 144 patients) were included. Compared with placebo, statins significantly reduced total cholesterol (42 studies, 6390 patients; weighted mean difference −42.28 mg/dl (1.10 mmol/l), 95% confidence interval −47.25 to −37.32), low density lipoprotein cholesterol (39 studies, 6216 patients; −43.12 mg/dl (1.12 mmol/l), −47.85 to −38.40), and proteinuria (g/24 hours) (6 trials, 311 patients; −0.73 g/24 hour, −0.95 to −0.52) but did not improve glomerular filtration rate (11 studies, 548 patients; 1.48 ml/min (0.02 ml/s), −2.32 to 5.28). Fatal cardiovascular events (43 studies, 23 266 patients; relative risk 0.81, 0.73 to 0.90) and non-fatal cardiovascular events (8 studies, 22 863 patients; 0.78, 0.73 to 0.84) were reduced with statins, but statins had no significant effect on all cause mortality (44 studies, 23 665 patients; 0.92, 0.82 to 1.03). Meta-regression analysis showed that treatment effects did not vary significantly with stage of chronic kidney disease. The side effect profile of statins was similar to that of placebo. Most of the available studies were small and of suboptimal quality; mortality data were provided by a few large trials only. Conclusion Statins significantly reduce lipid concentrations and cardiovascular end points in patients with chronic kidney disease, irrespective of stage of disease, but no benefit on all cause mortality or the role of statins in primary prevention has been established. Reno-protective effects of statins are uncertain because of relatively sparse data and possible outcomes reporting bias.

Deletions of CDKN2C in Multiple Myeloma : Biological and Clinical Implications

Abstract: Purpose: Deletions of chromosome 1 have been described in 7% to 40% of cases of myeloma with inconsistent clinical consequences. CDKN2C at 1p32.3 has been identified in myeloma cell lines as the potential target of the deletion. We tested the clinical impact of 1p deletion and used high-resolution techniques to define the role of CDKN2C in primary patient material. Experimental Design: We analyzed 515 cases of monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and newly diagnosed multiple myeloma using fluorescence in situ hybridization (FISH) for deletions of CDKN2C. In 78 myeloma cases, we carried out Affymetrix single nucleotide polymorphism mapping and U133 Plus 2.0 expression arrays. In addition, we did mutation, methylation, and Western blotting analysis. Results: By FISH we identified deletion of 1p32.3 (CDKN2C) in 3 of 66 MGUS (4.5%), 4 of 39 SMM (10.3%), and 55 of 369 multiple myeloma cases (15%). We examined the impact of copy number change at CDKN2C on overall survival (OS), and found that the cases with either hemizygous or homozygous deletion of CDKN2C had a worse OS compared with cases that were intact at this region (22 months versus 38 months; P = 0.003). Using gene mapping we identified three homozygous deletions at 1p32.3, containing CDKN2C, all of which lacked expression of CDKN2C. Cases with homozygous deletions of CDKN2C were the most proliferative myelomas, defined by an expression-based proliferation index, consistent with its biological function as a cyclin-dependent kinase inhibitor. Conclusions: Our results suggest that deletions of CDKN2C are important in the progression and clinical outcome of myeloma.

Relationship between symptom load of gastro-oesophageal reflux disease and health-related quality of life, work productivity, resource utilization and concomitant diseases: survey of a US cohort.

Abstract: BACKGROUND: Analysis of the burden of gastro-oesophageal reflux disease (GERD) in relation to the severity and frequency of symptoms is essential to identify individuals and groups in whom targeted ...

Low thermal conductivity in nanoscale layered materials synthesized by the method of modulated elemental reactants

Abstract: We report the room-temperature, cross-plane thermal conductivities, and longitudinal speeds of sound of multilayer films [(TiTe2)3(Bi2Te3)x(TiTe2)3(Sb2Te3)y]i (x=1−5,y=1−5) and misfit-layer dichalcogenide films [(PbSe)m(TSe2)n]i (T=W or Mo, m=1–5, and n=1–5) synthesized by the modulated elemental reactants method. The thermal conductivities of these nanoscale layered materials fall below the predicted minimum thermal conductivity of the component compounds: two times lower than the minimum thermal conductivity of Bi2Te3 for multilayer [(TiTe2)3(Bi2Te3)x(TiTe2)3(Sb2Te3)y]i films and five to six times lower than the minimum thermal conductivity of PbSe for misfit-layer dichalcogenides [(PbSe)m(TSe2)n]i. We attribute the low thermal conductivities to the anisotropic bonding of the layered crystals and orientational disorder in the stacking of layered crystals along the direction perpendicular to the surface.

Pure Red Cell Aplasia Induced by Erythropoiesis-Stimulating Agents

Abstract: Pure red cell aplasia in patients who are treated for anemia of chronic kidney disease with erythropoiesis-stimulating agents such as epoetin was first reported in 1998. Although the incidence of pure red cell aplasia peaked in 2002, it remains important for nephrologists to know how to investigate a suspected case of pure red cell aplasia and how to identify other causes of hyporesponsiveness to erythropoiesis-stimulating agents, which account for the vast majority of such cases. The authors reviewed the current status of information in the literature and drew on their personal experiences with patients regarding the diagnosis and management of epoetin-induced pure red cell aplasia. The mechanism for development of epoetin-induced pure red cell aplasia remains unconfirmed. It generally occurs after the production of neutralizing anti-erythropoietin antibodies. Elucidation of a suspected pure red cell aplasia case requires a systematic approach, beginning with simple measurements such as blood cell counts, because most cases of erythropoiesis-stimulating agent hyporesponsiveness are attributable to other causes. If these criteria indicate that the patient's response to erythropoiesis-stimulating agent therapy is very poor, then bone marrow examination and measurement of anti-erythropoietin antibodies is justified. If pure red cell aplasia is confirmed, then cessation of erythropoiesis-stimulating agent therapy and initiation of immunosuppressive therapy are recommended. Continued study of epoetin-induced pure red cell aplasia is needed to help nephrologists prevent or manage future cases and will have implications for the use of other protein-based therapeutic agents.

The impact of automated eGFR reporting and education on nephrology service referrals

Abstract: Background. Serum creatinine concentration is an unreliable and insensitive marker of chronic kidney disease (CKD). To improve CKD detection, the Australasian Creatinine Consensus Working Committee recommended reporting of estimated glomerular filtration rate (eGFR) using the four-variable Modification of Diet in Renal Disease (MDRD) formula with every request for serum creatinine concentration. The aim of this study was to evaluate the impact of automated laboratory reporting of eGFR on the quantity and quality of referrals to nephrology services in Southeast Queensland, Australia. Methods. Outpatient referrals to a tertiary and regional renal service, and a single private practice were prospectively audited over 3-12 months prior to and 12 months following the introduction of automated eGFR reporting and concomitant clinician education. The appropriateness of referrals to a nephrologist was assessed according to the Kidney Check Australia Taskforce (KCAT) criteria. Significant changes in the quantity and/or quality of referrals over time were analysed by exponentially weighed moving average (EWMA) charts with control limits based on ±3 standard deviations. Results. A total of 1019 patients were referred to the centres during the study period. Monthly referrals overall increased by 40% following the introduction of eGFR reporting, and this was most marked for the tertiary renal service (52% above baseline). The appropriateness of nephrologist referrals, as adjudicated by the KCAT criteria, fell significantly from 74.3% in the 3 months pre-eGFR reporting to 65.2% in the 12 months thereafter (P < 0.05). Nevertheless, a greater absolute number of CKD patients were appropriately being referred for nephrologist review in the post-eGFR period (24 versus 15 per month). Patients referred following the introduction of eGFR were significantly more likely to be older (median 63.2 versus 59.3 years, P < 0.05), diabetic (25 versus 18%, P = 0.05) and have stage 3 CKD (48% versus 36%, P < 0.01). Conclusion. The introduction of automated eGFR calculation has led to an overall increase in referrals with a small but significant decrease in referral quality. The increase in referrals was seen predominantly in older and diabetic patients with stage 3 CKD and appeared to result in net benefit.

Kidneys from patients with small renal tumours: a novel source of kidneys for transplantation.

Abstract: OBJECTIVE To report the use of a novel donor source as a further option to increase the number of patients who might be able to receive a renal transplant. PATIENTS AND METHODS Between May 1996 and July 2007, 43 kidneys were transplanted using kidneys obtained from patients with small (<3 cm diameter) incidentally detected tumours. After bench surgery to excise the tumour, they were all successfully transplanted into patients who were elderly or had significant comorbidities. RESULTS Apart from four patients who died from unrelated illnesses, all grafts continued to function with a median and mean follow-up of 25 and 32 months. The follow-up, which included 3-monthly renal ultrasonography and chest X-rays, showed only one case of tumour recurrence, which occurred 9 years after transplantation; the patient remains stable under observation after 18 months. CONCLUSIONS From our experience we consider that where nephrectomy is used for small, localized, incidentally detected renal tumours, the kidney should be considered for transplantation into carefully selected patients. Such patients with numerous medical comorbidities might benefit from renal transplantation, but not survive the waiting period if they are dependent on a deceased donor graft. Paradoxically the use of these marginal kidneys has the potential to increase the quality and length of life of these patients, despite the apparent contradiction of an intuitive principle of organ transplantation and immunosuppression.

Determination of the composition of Ultra-thin Ni-Si films on Si: constrained modeling of electron probe microanalysis and x-ray reflectivity data

Abstract: The homogeneous bulk assumption used in traditional electron probe microanalysis (EPMA) can be applied for thin-layered systems with individual layers as thick as 50 nm provided the penetration depth of the lowest accelerating voltage exceeds the total film thickness. Analysis of an NIST Ni-Cr thin film standard on Si using the homogeneous model yielded certified compositions and application of the same model to ultra-thin Ni-Si layers on GaAs yielded their expected compositions. In cases where the same element is present in multiple layers or in the substrate as well as the film, the homogeneous assumption in EPMA alone is not sufficient to determine composition. By combining x-ray reflectivity (XRR) thickness and critical angle data and using an iterative approach, quantitative compositional data in EPMA can be achieved. This technique was utilized to determine the composition of Ni-Si ultra-thin films grown on silicon. The Ni-Si composition determined using this multi-instrumental technique matched that of Ni-Si films simultaneously deposited on GaAs. Copyright © 2008 John Wiley & Sons, Ltd.

Contribution of plant photosynthate to soil respiration and dissolved organic carbon in a naturally recolonising cutover peatland

Abstract: The aim of this study was to investigate how three vascular plant species (Calluna vulgaris, Eriophorum angustifolium and Eriophorum vaginatum) colonising an abandoned cutover peatland affect fluxes of recent photosynthate to dissolved organic carbon (DOC), soil and plant respiration and shoot biomass. We used in situ 13CO2 pulse labelling to trace carbon (C) throughout a 65 day pulse chase period. Between 16 and 35% of the pulse of 13C remained in shoot biomass after 65 days with significant differences between C. vulgaris and E. angustifolium (P = 0.009) and between C. vulgaris and E. vaginatum (P = 0.04). A maximum of 29% was detected in DOC beneath labelled plants and losses of 13C from peat respiration never exceeded 0.16% of the original pulse, showing that little newly fixed C was allocated to this pool. There were no significant differences between the different plant species with respect to 13C recovered from DOC or via peat respiration. More C was lost via shoot respiration; although amounts varied between the three plant species, with 4.94–27.33% of the 13C pulse respired by the end of the experiment. Significant differences in 13C recovered from shoot respiration were found between C. vulgaris and E. angustifolium (P = 0.001) and between E. angustifolium and E. vaginatum (P = 0.032). Analysis of δ13C of microbial biomass indicated that recently assimilated C was allocated to this pool within 1 day of pulse labelling but there were no significant differences in the 13C enrichment of the microbial biomass associated with the different plant species. The data suggest that peat respiration represents a small flux of recent assimilate compared to other fluxes and pools and that different vascular plant species show considerable variation in the quantities and dynamics of C allocated to DOC.

Plant community composition, not diversity, regulates soil respiration in grasslands

Abstract: Soil respiration is responsible for recycling considerable quantities of carbon from terrestrial ecosystems to the atmosphere. There is a growing body of evidence that suggests that the richness of plants in a community can have significant impacts on ecosystem functioning, but the specific influences of plant species richness (SR), plant functional-type richness and plant community composition on soil respiration rates are unknown. Here we use 10-year-old model plant communities, comprising mature plants transplanted into natural non-sterile soil, to determine how the diversity and composition of plant communities influence soil respiration rates. Our analysis revealed that soil respiration was driven by plant community composition and that there was no significant effect of biodiversity at the three levels tested (SR, functional group and species per functional group). Above-ground plant biomass and root density were included in the analysis as covariates and found to have no effect on soil respiration. This finding is important, because it suggests that loss of particular species will have the greatest impact on soil respiration, rather than changes in biodiversity per se.

Long-term nitrogen deposition increases phosphorus limitation of bryophytes in an ombrotrophic bog

Abstract: Here we investigate the effect of 4 years simulated atmospheric deposition of ammonium (NH4) and nitrate (NO3), applied alone or in combination with phosphorus and potassium (PK), on the surface phosphatase activities and nutrient acquisition behaviour of two species of moss (Sphagnumcapillifolium and Hypnum jutlandicum) from an ombrotrophic peatland. Phosphatase activity was significantly enhanced by both the NH4 and NO3 treatments, particularly for Sphagnum, but the activity decreased when exposed to additions of PK. Regression analysis revealed that phosphatase activity on Sphagnum was positively related with tissue N and negatively related to tissue P concentrations. For Hypnum, a negative relationship between shoot P concentration and phosphatase activity was observed. Using a 32P tracer, mosses removed from plots receiving PK in combination with NH4 maintained their affinity for increased phosphorus uptake. These findings suggest that enhanced nutrient supply, even at modest doses, significantly alter the nutrient recycling behaviour of bryophytes.

A flow injection electrospray ionization tandem mass spectrometric method for the simultaneous measurement of trimethylamine and trimethylamine N-oxide in urine.

Abstract: Key metabolites for the diagnosis of the genetic disorder trimethylaminuria are trimethylamine (TMA) and trimethylamine N-oxide (TMAO) A rapid, automatable flow injection ESI-MS/MS method for their measurement in urine has been developed The TMA was derivatized with ethyl bromoacetate to form ethyl betaine bromide The 2 min ESI-MS/MS analysis employed four multiple reaction monitoring (MRM) ion pairs for derivatized TMA (1461, 1181), derivatized (2)H(9)-TMA (1551, 1271), TMAO (761, 581) and (2)H(9)-TMAO (851, 661) In control urine samples (n = 27) referred for suspected metabolic problems TMA was 011-119 mmol/mol creatinine, TMAO was 135-181 mmol/mol creatinine and the TMA/TMAO ratio was 00025-0055 In five patients with diagnosed trimethylaminuria, TMA was 53-230 mmol/mol creatinine, TMAO was 036-607 mmol/mol creatinine and the TMA/TMAO ratio was 020-134

Species-specific effects of plants colonising cutover peatlands on patterns of carbon source utilisation by soil microorganisms

Abstract: Root exudates and litter are the main sources of inputs of labile carbon into the microbial pool in successional ecosystems. Here we studied whether typical pioneer species (Eriophorum vaginatum, Eriophorum angustifolium and Calluna vulgaris) alter the functional response of the microbial community of a previously cutover peatland. Peat was sampled at three depths (0-5, 20-25 and 40-45 cm) from beneath these species and from bare soil areas. MicroResp analysis using ecologically relevant, radiolabelled, carbon sources showed significant separation in community level physiological profiles (CLPP) of soil microorganisms according to peat depth. This effect was also reflected in microbial biomass carbon, which also decreased with increasing depth. Furthermore, distinct differences in CLPP were observed between the three plant species and the bare soil in the absence of an effect on microbial biomass carbon or total soil carbon. The plant species effects were driven by differential utilisation of xylose, glutamic acid, lysine and phenylethylamine. The data suggest that 'new' carbon inputs from plants colonising abandoned cutover peatland may support communities of microorganisms that have functionally distinct roles in carbon turnover.

In vitro activation of rat brain protein kinase C by polyenoic very-long-chain fatty acids.

Abstract: A variety of fatty acids including the cis-polyunsaturated very-long-chain fatty acids (VLCFA) (> 22 carbon atoms) common in retina, spermatozoa, and brain were examined for their ability to activate protein kinase C (PKC) purified from rat brain. Arachidonic [20:4(n-6)], eicosapentaenoic [20:5(n-3)], and docosahexaenoic [22:6(n-3)] acids as well as the VLCFA dotriacontatetraenoic [32:4(n-6)] and tetratriacontahexaenoic [34:6(n-3)] were equally capable of activating PKC in vitro with maximal activity being between 25 and 50 microM. The phorbol ester 12-O-tetradecanoylphorbol 13-acetate further enhanced the in vitro activation of PKC when added to the protein kinase assay system with the fatty acids. The fully saturated arachidic acid (20:0) was inactive in both assay systems. The potential significance of the in vitro activation of PKC by the VLCFA is discussed.

Sustaining ecosystem services in ancient limestone grassland: importance of major component plants and community composition

Abstract: Summary 1Limestone grasslands are among the most floristically rich ecosystems in northern Europe and have recently been shown to sustain ecosystem functioning under conditions of heavy nitrogen (N) deposition. Here we report a long-term mesocosm experiment, designed to measure the importance of major component plants and community composition in providing ecosystem services (in particular preventing leaching of inorganic N). 2A number of important steps were taken in the experimental design to increase conformity of the experimental communities to real limestone pasture, including using natural soils, plant cuttings of limestone grassland provenance and simulated management. Furthermore, communities were allowed to establish for 8 years before measurements were made. 3Leaching of and were found to differ by up to a considerable two orders of magnitude according to functional group composition, with sedges and forbs leaching the most. Grass communities and communities containing all three functional groups (grasses, sedges and forbs) leached similarly low amounts of and . 4Levels of soil and followed a similar pattern of inter-community differences to leaching, while vegetation biomass and vegetation N stocks were very similar between communities consisting of only grasses, only sedges and the most species rich community (4 grasses + 4 sedges + 4 forbs). 5Perennial grasses appeared to play the key role in inorganic N retention, with communities consisting of these plants having equally low leaching as more species rich communities. Indeed, most ecosystem services were performed comparatively well by grass communities as by the most species rich community. 6No overall effects on provision of services resulted from mixing functional groups or increasing the number of species representing each functional group. 7Synthesis. This work shows that more than order-of-magnitude differences in provision of ecosystem services can occur between species that coexist naturally in ancient limestone pasture. However, despite these large differences, because of the key role played by grasses, expected shifts in community composition anticipated as a result of N pollution may not impair the capacity of these systems to provide ecosystems services.

Viability and fertilizing capacity of cryopreserved sperm from three North American acipenseriform species: a retrospective study

Abstract: Populations of sturgeon across the globe are threatened due to unregulated harvest and habitat loss, and the status varies among species across North America. Ready access to viable and functional sperm would contribute to recovery programmes for these species. In this study, we examined the motility, viability (cell membrane integrity) of cryopreserved sperm from three North American acipenseriform species and fertilizing capacity. Milt samples were collected from captive shortnose sturgeon (Acipenser brevirostrum), wild paddlefish (Polyodon spathula) and pallid sturgeon (Scaphirhynchus albus) and cryopreserved using combinations of Modified Tsvetkova �s (MT) extender, Original Tsvetkova�s extender, and modified Hanks� balanced salt solution, along with the cryoprotectants methanol (MeOH) or dimethyl sulfoxide (DMSO). A dual-staining technique using the fluorescent stains SYBR-14 and propidium iodide was employed with flow cytometry to determine the percentages of spermatozoa that were viable by virtue of having intact membranes. The percentage of viable spermatozoa ranged from 5% to 12% in shortnose sturgeon, 30–59% in paddlefish, and 44–58% in pallid sturgeon. In the first experiment with shortnose sturgeon sperm, methanol allowed for higher values for dependent variables than did DMSO, and sperm viability generally correlated with post-thaw motility. However, fertilization rate, neurulation, or hatching rates were independent from these factors. In the second experiment with shortnose sturgeon, 5% MeOH combined with MT yielded higher values for all parameters tested than the other combinations: viability was correlated with motility, fertilization rate, and hatching rate. Overall, viability and post-thaw motility was not affected by the use of hyperosmotic extenders (OT) or cryoprotectants (DMSO), but their use decreased fertilization percentages. For paddlefish sperm (experiment 3), MT combined with 10% MeOH was clearly a good choice for cryopreservation; viability and motility results were correlated, but independent of fertilization. For pallid sturgeon sperm (experiment 4), MT with 5–10% MeOH showed significantly higher sperm quality and fertilization parameters. Membrane integrity can be used as a predictor of fertilization by cryopreserved sperm, however additional sperm quality parameters, supplementary to motility and membrane integrity, would be useful in the refining and optimizing cryopreservation protocols with acipenseriform sperm.

Designed Synthesis of Families of Misfit‐Layered Compounds

Abstract: The synthesis of several new families of misfit-layered compounds is demonstrated. These compounds are crystalline along the c-axis and in the ab-plane, but show very short coherence lengths between ab-planes. This disorder leads to ultra-low and tunable thermal conductivity. Annealing isostructural samples under a chalcogen vapour until equilibrium is reached results in reproducible Seebeck and resistivity values. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

A new prognosticator for post-transplant lymphoproliferative disorders after renal transplantation.

Abstract: Antonioli, E., Guglielmelli, P., Pancrazzi, A., Bogani, C., Verrucci, M., Ponziani, V., Longo, G., Bosi, A. & Vannucchi, A.M. (2005) Clinical implications of the JAK2 V617F mutation in essential thrombocythemia. Leukemia, 19, 1847–1849. Campbell, P.J. & Green, A.R. (2006) The myeloproliferative disorders. New England Journal of Medicine, 355, 2452–2466. Campbell, P.J., Scott, L.M., Buck, G., Wheatley, K., East, C.L., Marsden, J.T., Duffy, A., Boyd, E.M., Bench, A.J., Scott, M.A., Vassiliou, G.S., Milligan, D.W., Smith, S.R., Erber, W.N., Bareford, D., Wilkins, B.S., Reilly, J.T., Harrison, C.N. & Green, A.R. (2005) Definition of subtypes of essential thrombocythaemia and relation to polycythaemia vera based on JAK2 V617F mutation status: a prospective study. Lancet, 366, 1945–1953. Campbell, P.J., Scott, L.M., Baxter, E.J., Bench, A.J., Green, A.R. & Erber, W.N. (2006) Methods for the detection of the JAK2 V617F mutation in human myeloproliferative disorders. Methods in Molecular Medicine, 125, 253–264. Cheung, B., Radia, D., Pantelidis, P., Yadegarfar, G. & Harrison, C. (2006) The presence of the JAK2 V617F mutation is associated with a higher haemoglobin and increased risk of thrombosis in essential thrombocythaemia. British Journal of Haematology, 132, 244–245. Finazzi, G., Rambaldi, A., Guerini, V., Carobbo, A. & Barbui, T. (2007) Risk of thrombosis in patients with essential thrombocythemia and polycythemia vera according to JAK2 V617F mutation status. Haematologica, 92, 135–136. Imbert, M., Pierre, R., Thiele, J., Vardiman, J.W., Brunning, R.D. & Flandrin, G. (2001) Essential thrombocythaemia. In: WHO classification of tumors: tumors of hematopoietic and lymphoid tissues (ed. by E.S. Jaffe, N.L. Harris, H. Stein and J.W. Vardiman), pp. 39–41. IARC Press, Lyon. Wolanskyj, A.P., Lasho, T.L., Schwager, S.M., McClure, R.F., Wadleigh, M., Lee, S.J., Gilliland, D.G. & Tefferi, A. (2005) JAK2 mutation in essential thrombocythaemia: clinical associations and long-term prognostic relevance. British Journal of Haematology, 131, 208–213.